Zeitschriften und Ausgaben

Volumen 26 (2019): Heft 4 (December 2019)

Volumen 26 (2019): Heft 3 (September 2019)

Volumen 26 (2019): Heft 2 (June 2019)

Volumen 26 (2019): Heft 1 (March 2019)

Volumen 25 (2018): Heft 4 (December 2018)

Volumen 25 (2018): Heft 3 (September 2018)

Volumen 25 (2018): Heft 2 (June 2018)

Volumen 25 (2018): Heft 1 (March 2018)

Volumen 24 (2017): Heft 4 (December 2017)

Volumen 24 (2017): Heft 3 (September 2017)

Volumen 24 (2017): Heft 2 (June 2017)

Volumen 24 (2017): Heft 1 (March 2017)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2354-0133
Erstveröffentlichung
20 Dec 2019
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

Volumen 25 (2018): Heft 3 (September 2018)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2354-0133
Erstveröffentlichung
20 Dec 2019
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

68 Artikel
Uneingeschränkter Zugang

Effect of the Type of Aging after Supersaturating on Hardness and AW-7020 Stop Structure

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 9 - 16

Zusammenfassung

Abstract

Aluminum alloy AW-7020 is characterized by high fatigue strength. It is used primarily in welded constructions, which should be characterized by high strength and resistance to cyclically variable operational loads. They have found wide application in light welded ship constructions, bridge-carrying elements, cranes, hoists, vehicles, roof beams in roof constructions, and security barriers. The paper attempts to determine the influence of selected types of applied heat treatment on the structure and hardness of the AW-7020 alloy used in the shipbuilding industry. Heat treatment processes have been described in the aspect of improving the mechanical and strength properties of the tested alloy and its impact on ductility. Several supersaturation and aging sequences were used in the course of the study. The results of hardness tests of aluminum alloy after its earlier supersaturation and aging (natural and artificial) have been presented. Photographs of internal structures in individual sequences were taken. The obtained hardness measurement results and analysis of structures in individual states were compared with the delivery condition. To illustrate selected heat treatment processes, transient tests were also performed to accurately verify the effect of aging after saturation on hardness and changes occurring in the material structures. The results of the material tests showed that the type of heat treatment after saturation is of significant importance for the hardness and structures of the AW-7020 alloy. As a result of the research, it was proved that the tested alloy obtained in the artificial aging process more favourable strength properties, in a shorter period, compared to the use of the natural aging process.

Schlüsselwörter

  • AW 7020 alloy
  • natural aging
  • artificial aging
  • saturation
  • hardness
  • ductility
  • internal structure
Uneingeschränkter Zugang

Study of the Pilot’s Attention in the Cabin During the Flight

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 17 - 24

Zusammenfassung

Abstract

The pilot, while performing certain tasks or being in the battlefield environment works in a time lag. He is forced to properly interpret the information and quickly and correctly take action. Therefore, the instruments in the cabin should be arranged in such a way that they are legible and the operator have always-easy access to them. Due to the dynamics of the aircraft and the time needed to process the information by the pilot, a reaction delay occurs, resulting in the plane flying in an uncontrolled manner even up to several hundred meters. This article discusses the VFR and IFR flight characteristics, the pilot’s attention during flight, cabin ergonomics, and the placement of on-board instruments having a significant impact on the safety of the task performed in the air. In addition, tests have been carried out to determine exactly what the pilot’s eye is aimed at while completing the aerial task. Six basic devices were identified: altimeter, artificial horizon, speedometer, turn indicator with transverse gauge, variometer and heading indicator. They also started to think about how to position them in relation to each other in order to achieve the best results in terms of ergonomics, which include, minimizing time of reading individual parameters, grouping devices with parameters closely related to each other, reducing to a minimum the value of errors during reading and the smallest possible pilot’s effort.

Schlüsselwörter

  • transport
  • battlefield environment
  • pilot reaction delay
  • device parameters
  • parameters reading time
Uneingeschränkter Zugang

Aerodynamics of Articulated Multilink Trucks

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 25 - 32

Zusammenfassung

Abstract

Development of new generations of supersize heavy-duty highway trucks for cargoes transportation on long and super long distances between Europe, Asia and Far East is actual now. New trucks shall reduce amount of transport on roads and quantity of drivers, involved in the transportation, will raise economic efficiency and safety of transportations and reduce fuel consumption, CO2, and harmful emissions. Multilink trucks (number of trailed links is three and more and the total truck length is above 40 m) are to achieve designated purposes and thus are under the scope in the article. The advantages of multilink trucks are formed mainly by reducing the cost of power to overcome the aerodynamic resistance of each co-trailer unit in comparison with the head element. However, the airflow in every trailer-trailer gap has been not studied for articulated vehicles such as multilink highway trucks. This zone of the truck is characterized by a rather large length and height, and the condition of the air mass is influenced by airflow from the roof, side panels and area under the bottom of a truck links. A study of this task will help us to analyse aerodynamic losses mechanics in the trailer-trailer gap and to come to new effective and substantiated decision allowing power loss and thus fuel consumption reduction. The study lists the general calculation method evaluating the aerodynamic characteristics of the multilink truck on the base of numerical simulation of fluid dynamics using Flow Vision software. During calculation, there were determined speed distribution and power lines along the truck, the distribution of pressure on the truck surface, power and full drag coefficient. The results obtained allowed numerically evaluate the effect of the distance between the links on fuel consumption for multilink trucks and define the desired changes in their design.

Schlüsselwörter

  • truck
  • aerodynamic resistance
  • articulated truck
  • trailer-trailer gap
  • modelling
Uneingeschränkter Zugang

Torgas Condensate Combustion in the SI Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 33 - 38

Zusammenfassung

Abstract

The article presents results from IC engine tests on combustion of alcohol fuel with the addition of torgas condensate. Torgas is a by-product created from the torrefaction of Sida hermaphrodita. It was obtained from torrefaction carried out at a temperature of 400°C. Torgas was condensed in a tubular cooler. The basic fuel was butanol. This fuel was chosen, because regular hydrocarbon based fuels got delaminated while blended with torgas condensate. The condensate dissolves in alcohol therefore the choice was justified. In the mixture, the volume ratio of alcohol to condensate was 4:1. The combustion was carried out in a spark-ignition, single-cylinder engine with a cubic capacity of 650 cm3. The engine was able to vary its compression ratio. The engine worked at full load at maximum open throttle. The engine body was heated to a temperature of 95°C and this temperature was maintained throughout the testing period. The engine was running at 850 rpm. The first stage of the experiment included determination of the optimal ignition angle for butanol as a reference fuel and for a mixture of butanol and torgas condensate. The optimal spark angle was estimated based on the maximum indicated work. Three compression ratios, i.e.: CR=8.8, 10 and 11.2 were used. All tests were performed for a stoichiometric air fuel ratio. The obtained in-cylinder pressure diagrams for the reference fuel and the fuel with the addition of condensate were compared with each other. The rate of pressure increase inside the cylinder was calculated. For all tests, the following exhaust components were measured: CO2, CO and HC.

Schlüsselwörter

  • SI engine
  • butanol
  • bio-oil
  • torgas condensate
  • exhaust emission
  • torrefaction
Uneingeschränkter Zugang

Optimisation of Aircraft Position in the Formation Flight for the Drag Reduction

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 39 - 50

Zusammenfassung

Abstract

This article presents optimisation of necessary flight thrust in a V-shaped flight formation of small-unmanned plane “Sikorka”. At the beginning is showed analyse of birds behaviour. Their formation flying was the cause of attention in order to minimalize fuel consumption. Afterwards there are overlooked scientific articles about the formation flying subject contain pure physic analyses, and articles about researches which was made in order to explain economic beneficial for airlines. Thus, the article presents mathematical model, which was optimised for three different starting position of a longitudinal axis. After optimisation there are presented results of the wingman position in regard of the leader. Influence of the calculation results on the formation flying was analysed, allowing for some conclusions about the future of the UAV’s flights. The given process is aimed to achieve the best (optimal) solution from the point of view of the specific criterion. The following most important terms can be distinguished within the optimization process: decisive variables – parameters determining the basic project assumptions. The basic design variables and design constrains are described.

Schlüsselwörter

  • UAV
  • formation flying
  • optimisation
  • dynamic of flight
  • aerodynamic
Uneingeschränkter Zugang

Numerical Analysis of Heat Conduction Influence on SCR Aftertreatment Systems Efficiency

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 51 - 58

Zusammenfassung

Abstract

Selective Catalytic Reduction (SCR) is well known method for reducing NOx emission in diesel engine exhaust gas. Urea-water solution (UWS) injected into hot stream decomposes due to thermolysis into ammonia and isocyanic acid which hydrolyses further into more ammonia and carbon dioxide. Resultant ammonia is the NOx reductor, producing water vapour and carbon dioxide from the reduction reaction. To provide sufficient NOx reduction efficiency, UWS needs to be properly atomized and mixed with exhaust gas. However, due to more and more restrictive emissions regulations provided by European Union and Close Coupled trend of aftertreatment systems in vehicles the design process is very complex and demanding. Computational Fluid Dynamics (CFD) simulations are integral part of product development, allowing save time and reduce costs of preparing prototypes for further tests. However, it is necessary to understand all the processes and problems connected with NOx reduction in SCR system. Strong turbulent flow of hot stream gas, urea-water solution spray injection, droplets interaction with wall, wallfilm generation are included. The objective of this work is to investigate the impact of heat transfer modelling inside mixing elements of SCR system on urea mixing uniformity and wallfilm deposit on the walls of the system. Simplified and more complex approach is compared with no heat transfer cases. All the simulations were conducted using AVL FIRETM software. Results showed that wall heat transfer might have an impact on mixing efficiency and wallfilm formulation. It is necessary to take into account the effect of mixing elements heat conduction in CFD simulations during the aftertreatment design process.

Schlüsselwörter

  • SCR
  • simulation
  • heat conduction
  • aftertreatment
Uneingeschränkter Zugang

Light Absorption Properties of ‘Petrobaltic’ Oil-in-Water Emulsion Present in Seawater

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 59 - 64

Zusammenfassung

Abstract

In the article, the characteristic of crude oil ‘Petrobaltic’ potentially present in the Baltic Sea water masses is considered in relation to the protection of marine environment. The main spectroscopic method to characterize various oils (crudes and refinery products like fuels and lubricating oils) is fluorescence. However, the absorbance measurements of oils are necessary due to the partial overlapping the spectra of natural seawater components and oil substances. Therefore, properties of crude oil are considered to expand the basis of spectroscopic properties of oils – typical marine organic pollutants – based on absorption measurements. Oils potentially found in the marine environment are, in addition to surface forms, also in-depth ones as oil-in-water emulsion. Therefore, in the article crude oil as oil-in-water emulsion form is considered. As a solvent demineralised water with salinity, corresponding to Baltic Sea salinity was used. Several concentrations of dispersed crude oil were prepared. The absorbance spectra in the UV and visual range of the light in the range from 240 to 600 nm, for each prepared samples are discussed. Based on the Lambert-Beer law for each wavelength of excitation, in the range 240-600 nm, the specific parameter absorption coefficient was determined. Obtained results indicate the rapid decreasing of the absorbance for this kind of oil in the wavelength range from 240 nm to 420 nm. However, in the shape of absorbance spectra is observed the characteristic wide and flat peak located at 260 nm for excitation wavelength, which could be a specific point for this kind of oil.

Schlüsselwörter

  • crude oil
  • absorbance
  • absorption spectra of dispersed oil
  • absorption coefficient
  • oil-in-water emulsion
Uneingeschränkter Zugang

Analysis of the Procedure of Evaluation of the Technical Condition of a High-Pressure Common Rail Fuel Pump Using a Test Bed

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 65 - 70

Zusammenfassung

Abstract

Piston displacement pumps use in common rail fuel injection systems generates very high pressure, reaching even 300 MPa. Maintaining such a high pressure is possible thanks to very precise machining resulting in as little clearance between the piston-cylinder assemblies. Due to very high forces operating in the systems and relatively unfavourable lubrication conditions resulting from using fuel as lubricants, the pumps are subject to wear and consequently lose their operating parameters. The high cost of production of the pumps, resulting from their technological advancement, forced their manufacturers to introduce technologies for diagnosing and regenerating them. The diagnostics consists in removing the pump from the engine and having it verified using a test bed. The first stage consists of evaluating the pump’s flow at null pressure; follow by evaluation of its maximal delivery for the pressure of 100 MPa. The obtained values are compared to the values achieved by a new pump. The effect of negative evaluation on a test bed is the disassembly of the pump, verification of the condition of its parts and replacement of the damaged elements. The authors examined new and used pumps on a tested, aiming to determine the characteristics of delivery of a pump for various pressures. The objective of the research was to identify the actual points in the pump’s operation at which the delivery drops the most due to the wear. The highest difference in delivery was found to exist for the maximal compression pressure. The obtained results were analysed and the possibility of changing the pump diagnostics procedure with the use of a test bed was determined.

Schlüsselwörter

  • common rail
  • test bench
  • diagnostic
Uneingeschränkter Zugang

Evaluation of the Possibility of Occurrence of Selected Damage to a Car Engine Turbocharger Using the Event Tree Analysis (ETA)

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 71 - 76

Zusammenfassung

Abstract

The subject of the article is the identification of factors behind the incorrect operation of a car turbocharger that, in longer perspective, lead to the damage of the device. Due to the operating principle and design features, the device works with many engine systems – intake, exhaust, lubrication systems and also, increasingly more often, with the cooling system. A multitude of relations, complexity, and working conditions are reasons due to which the device is sensitive to disturbances of quality parameters of the working media (e.g. oil). In the article based on the selected causes of damage of turbochargers, we focused on the following initiating event, concerning the bearings lubrication system, which is clogged oil strainer. The authors aims at performing an analysis allowing to increase the detectability of emerging malfunctions that lead to deterioration of operating conditions of the device. For this task tool such as ETA (Event Tree Analysis) was used. It is a tool for assessing system and process safety. It facilitates detecting potential risks, as well as relations existing between actions or events. This method explores the path from the initiating event to the outcome (most often representing the immobilization of the tested object), with particular emphasis on intermediate stages affecting the technical condition of the object. Unlike the FTA analyses, which have a deductive nature, the ETA analysis is inductive. The analysis of the obtained results, supported with validation by means of ETA, allowed proving that, given the current state of knowledge and advancements in technology, it is possible to apply additional sensors for monitoring the operation of a turbocharger. The proposed modifications were considered minor design changes that significantly increase the reliability of the device.

Schlüsselwörter

  • turbocharger
  • combustion engines
  • Event Tree Analysis
  • ETA
Uneingeschränkter Zugang

Volatile Organic Compounds Removal From Vehicle Interior Based on Photocatalytic Solution

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 77 - 84

Zusammenfassung

Abstract

The article presents results of research work which aim was development of solution for volatile organic compounds (VOCs) removal from vehicle indoor air. VOCs, especially benzene, toluene, and xylene (BTX), are air pollutants responsible for many civilizational diseases because of its carcinogenic and mutagenic properties. Concentration of those substances can be even few times higher in micro atmosphere of vehicle cabin than in other indoor atmospheres [1]. The aim of the scientific cooperation between Dr. Schneider Automotive Polska and the Wroclaw University of Science and Technology (WUST) is research on innovative (international range), product development – photocatalytic reactor characterized by Volatile Organic Compounds, especially BTX removal properties. The BTX reduction effectiveness, caused by photocatalytic reactor application in vehicle ventilation system, was subjected to in-depth analysis. The results showed difference on not only maximal benzene, toluene, and xylene reduction (separately) but also in the pattern of response surface. In some tested parameters, the hazardous compounds (as a BTX sum) were reduced for almost 70%. The photocatalytic reactor seems to be prospective solution for air quality improvement in any vehicle cabin.

Schlüsselwörter

  • automotive vehicle
  • benzene-toluene-xylene compounds
  • vehicle interior
  • indoor air
  • photocatalysis
Uneingeschränkter Zugang

Criteria of Similarity in Analysis of Main Dimensions and Propulsion Power of Ships at Preliminary Stage of Design

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 85 - 91

Zusammenfassung

Abstract

The article presents the methodology of calculation of principal parameters of ship’s hull dimensions, called „significant ships list”, at preliminary stage of design process. Knowledge collected in the database is related to new buildings classified according to type, displacement, or DWT, shipping class, maximum speed etc. Are analysed dimensional constraints due of Froude Number, ships dimensional coefficients block and weigh coefficient, relations of main dimensions such as L/B, B/T, L/H, B/H etc. [7]. Those parameters coming out from ship-owners requirements like type of ship, load capacity, type of cargo, shipping zone, speed and some more. Very helpful tool for such analysis is list of significant ships created for specified types of ships. Mentioned lists are very effective under conditions that cover broad-spectrum new buildings and data included are credible. Uncritical taking values included in significant ships list can lead to critical errors in selection of main dimensions of a ship or its propulsion powering. For that reasons, basing on analysis, as main criteria of similarity of ship’s hull were assumed mass coefficient, block coefficient and Froude Number [2]. That procedure has significant impact at proper estimation of propulsion power. Another reliable parameter of evaluation of power seems to be relation between power and load capacity Ne/D.

Schlüsselwörter

  • shipbuilding
  • calculation of hulls dimensions of ship and propulsive marine power
Uneingeschränkter Zugang

Effectiveness of the Active Pneumatic Suspension of the Operator’s Seat of the Mobile Machine in Depend of the Vibration Reduction Strategies

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 94 - 98

Zusammenfassung

Abstract

Low speeds of heavy mobile machines combined with large inertia result in the excitation of low frequency vibrations. Dissipation of vibration energy in the case of unsprung machines is performed only through tires, which slightly reduces the intensity of vibrations. Effective reduction of vibrations of mobile machines is possible only with active or semi-active methods. In unsprung mobile machines, on the way of propagation of vibrations between the source of vibrations and the protected object (machine operator), are vibroisolation systems located. These are most often controlled seat suspensions. In the case of the active suspensions, it is necessary to provide external energy, e.g. in the form of compressed air. The compressed air has the advantage that it is generally available in working machines as the working fluid and has its environmentally friendly properties (leaks do not contaminate the environment). This article is the result of the continuation of work on active methods of vibro-activity lowering in mobile machines, which resulted in, among others, elaboration of simulation model of the active operator’s seat suspension with controlled pneumatic actuator and its experimental identification. In particular, it was verifying the effectiveness of the adopted solution made the identification the friction model and thermodynamic phenomena in the controlled pneumatic cylinder. The aim of this work is parametric optimization of the suspension system and searching for the optimal control strategy. Experimental tests were carried out under conditions of harmonic excitations, coming from the electromechanical vibration exciter with controllable pitch and frequency. Data acquisition system and control circuit of the proportional directional control valve, supplying compressed air to the actuator were implemented using MATLAB-Simulink Real-Time software.

Schlüsselwörter

  • unsprung mobile machines
  • active vibration reduction
  • controlled suspension seats
  • pneumatic actuator
Uneingeschränkter Zugang

Test Flights in the Aircraft Operation Process

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 99 - 109

Zusammenfassung

Abstract

The article presents theoretical and practical aspects of aircraft reliability and safety of the performance of test flights in the operation process. The selected issues of operation of the means of transport in the aspect of the aircraft reliability, as well as the intensity of damage during the performance of test flights were presented. In short, the rules for operating the aircraft during test flights are described. A brief description of the causes of air crashes during test flights was presented, and the main hazards and risk occurring at the same time were shown. Subsequently, the authors’ methodology including a diagram for studying the aircraft features in terms of aerodynamic characteristics and performance and a model of the maintenance system of aircraft to perform the test flights, were demonstrated. The elements of the decision-making model, developed for this purpose, were briefly presented, showing the required and defined decision variables, constraints and an objective criterion function. The algorithm of the method was presented, and the examples of practical application and graphical data presentation in the DOSPIL application were indicated. The article was concluded with a short summary in which the main effects and directions of further work were presented.

Schlüsselwörter

  • aircraft test flights
  • organisation of test flights
  • testing of aircraft properties
Uneingeschränkter Zugang

Organization of the Highway Strip Repair Process

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 111 - 120

Zusammenfassung

Abstract

The article presents the possibilities of advance development of detailed organization-technical plans for the repair of Highway Strips, which will enable their effective use, particularly during combat operations – while maintaining the required time and technical standards at the same time. The main objectives of Highway Strips were presented; their role in securing military aviation activities and historical conditions for their creation. The concept of HS (Highway Strip) was defined along with the modern principles for their construction, modernization and renovation. Based on a selected example, the principles for evaluating the technical condition of their pavement and the repair possibility assessment were presented. At the same time, typical damage to HSs and factors affecting such damage were presented. Next, the methods and technologies for repairing various types of bituminous pavement damage repairs were discussed, with particular emphasis on the methods of repairing cracks, surface damage, deep damage and asphalt renovation. A schedule for the “Wielbark” highway strip was also developed, and the necessary calculations of the repair times, as well as the resources and resources for securing these operations were made. The article is concluded with a short summary and a proposal for further work, aimed at inhibiting the destructive processes of Highway Strips in Poland.

Schlüsselwörter

  • Highway strip
  • airfields
  • airstrips
  • runway repair processes
Uneingeschränkter Zugang

Implementation the GLONASS System in Aeronautical Application

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 121 - 128

Zusammenfassung

Abstract

The article determines the accuracy of positioning of the aircraft with the use of a satellite system GLONASS. In addition, the SPP (Single Point Positioning) absolute positioning method was utilized in research test in article. Research test was carried out in the new software APS (Aircraft Positioning Software), used for precise GPS/GLONASS satellite positioning in air navigation. The article describes the research method and presents mathematical formulas of the SPP positioning method. In the research test, the positioning accuracy of the Cessna 172 aircraft was obtained based on comparison of results between APS and RTKLIB software. The difference of Cessna 172 aircraft coordinates in the XYZ geocentric frame between the APS and RTKLIB solution is between −7 m to +6 m. The research material developed in the article comes from an aeronautical experiment carried out with the Cessna 172 aircraft for the EPDE military airport in Deblin.

Schlüsselwörter

  • Remote Maintenance System
  • air navigation
  • GLONASS
  • accuracy
  • Single Point Positioning method
Uneingeschränkter Zugang

Decomposition of Harmonic Wavelets of Torsional Vibrations as Basis for Evaluation of Combustion in Compression-Ignition Engines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 129 - 135

Zusammenfassung

Abstract

The aim of analysis presented in the article is results of measurements of torsional deflections of a crankshaft of three-cylinder internal combustion diesel engine. The wavelets of the run of torsional twists were processed by decomposition to harmonics using FFT. In order to exactly recognize all dynamic aspects of gas forces acting during working stroke, decomposition was done in two ways: first one relaying on records encompassing one working cycle (two revolutions), the second one based at separated periods encompassing angular an interval from TDC (Top Dead Centre) of one cylinder to TDC of subsequent in firing order. For three-cylinder engine, width of the interval is 240 degrees of crank angle. In order to obtain reliable results, torsional deflection signals acquisitions were recorded numerous times including changes of outer conditions (temperature, atmospheric pressure) and different values of the engine loads. The main goal of conducted experiments was looking for an answer of a question if exist any differences between frequency spectrums of harmonics of run of full cycle ( two revolutions) and the same cycle divided by three separate intervals. Analysis was conducted in order to state any possibility of diagnostic signals acquisition caused by abnormalities of combustion process. Results were presented in form of comparison of frequency spectra taken from full cycle and divided intervals.

Schlüsselwörter

  • diagnostics
  • diesel engine
  • torsional vibrations
  • signal processing
Uneingeschränkter Zugang

Physicochemical Properties of Fuel Compositions Obtained from Diesel Fuel and Different Kinds of Fatty Raw Material

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 137 - 143

Zusammenfassung

Abstract

Increased interest in development of alternative fuels used to power combustion engines is caused by excessive use of fuels obtained from mineral sources. Depletion of resources, political aspects as well as the negative impact on the environment are commonly discussed issues in relation to fossil fuels. On the other hand, biodegradability, lower toxic components emissions and interchangeability with mineral fuels are commonly described benefits related to biodiesel, interpreted as fatty acid methyl esters obtained from fatty raw material. Also the multiplicity of raw materials that can be used for production promotes popularization of the biodiesel. However the variety of raw materials can have significant impact on the number of physicochemical properties of alternative fuels due to the differences in molecular structures forming given type of raw material.

The article presents analysis of properties of different types of biodiesel and its mixtures with diesel according to the outlines presented in the quality standards for mineral and alternative fuels. Alternative fuels were produced in the laboratory setup from swine, poultry, rape and sunflower fatty raw material. Such parameters as: density, kinematic viscosity, flash point, acid value, oxidation stability, cold filter plugging point, sulphur content, water content and total contamination were examined, based on the results, the quality of the biofuels was evaluated. Study confirms that biofuels derived from plant origin fatty raw material present favorable results in the aspect water content, total contamination, acid value and cold flow properties, thus biofuels derived from animal origin raw fatty material presents lower density and sulphur content.

Schlüsselwörter

  • Biodiesel quality examination
  • biodiesel mixtures
  • animal fat biodiesel
  • vegetable oil biodiesel
  • transesterification
Uneingeschränkter Zugang

Influence of Biodiesel Origin on the Exhaust Gasses Concentration in Compression Ignition Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 145 - 152

Zusammenfassung

Abstract

The use of renewable fuels can reduce consumption of fossil fuels as well as diversify the range of alternative energy carriers. The advantage of biofuels is that they can be obtained from waste materials. Biofuels derived from vegetable or animal raw fatty material, as a result of transesterification, are characterized by similar physicochemical properties to mineral diesel fuel in terms of quality standards, however the fatty acid composition of the raw material can significantly influence exhaust gas emissions. The aim of the research is to determine the impact of the origin of various renewable biocomponents on exhaust gasses concentration emitted by compression ignition engine. The tests were conducted on a Common Rail, direct injection engine, operating under steady state conditions. Two kinds of biofuels produced from different fatty raw materials (rapeseed oil and swine lard) were used. All the experiments were performed on fuels containing a total of 50% biocomponent shares admixed to commercial diesel fuel. The tested samples included both: binary and ternary mixtures. During the experiments the differences in: hydrocarbons, carbon monoxide and nitrogen oxides concentrations were examined as a result of different fuel composition. The study shows that the best results were achieved for fuel containing both plant and animal biocomponents.

Schlüsselwörter

  • exhaust gas emission
  • common rail. biodiesel combustion
  • animal fat biodiesel mixtures
  • vegetable oil biodiesel mixtures
Uneingeschränkter Zugang

Engineering Support of the Quality of Surface Layer of Tab Grooves in the Discs Made From Heat-Resistant Steel

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 153 - 158

Zusammenfassung

Abstract

The main idea of the work is to create scientifically grounded technological conditions for treatment of tab grooves in the discs from heat resisting steel, which stipulate formation of roughness of treated surfaces at the level of design requirements, useful compressive residual stresses and a defective surface layer, which increases reliability of operation of interlock in the absence of any defects on the working surfaces of tab grooves of various types, under conditions of maximizing efficiency of their treatment method. Dependences of roughness of the treated surface on the technological factors of the broaching process Ra = f (V, S, γ, HRC) have been proposed. As a result of experimental studies, the nature of distribution of residual stresses, depth and degree of strengthening of the surface layer, depending on the technological conditions of the tab grooves treatment, has been established. The article presents research of surface quality parameters; study all the selected parameters of the surface quality and surface layer and an algorithm to perform experimental work. The algorithm has been built on major principles of control and fixation methods, which stipulate use of non-destructive methods of control. Graphs of strengthening the surface layer of samples, depending on their processing modes and graphs of the distribution of residual stresses in the surface layer are also presented.

Schlüsselwörter

  • surface quality parameters
  • tab grooves and interlocks
  • heat-resistant steel
Uneingeschränkter Zugang

X-ray Stress Measurements in the Institute of Aviation Possibilities and Examples

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 159 - 166

Zusammenfassung

Abstract

From the point of view of the airplane construction, its fatigue lifetime and exploitation process, the stress states and levels are of crucial importance. The most appropriate experimental methods to determine stress values are diffraction methods with different radiation type employed. These methods allow the determination of the elastic lattice deformation and distortion (effectively the stress state) from the displacement and broadening of the diffraction peak. Diffraction methods are widely known as the experimental methods for determining not only the stress values but also the elastic properties of polycrystalline materials (also of all alloys types used in the aerospace industry). The advantages of diffraction experiments result from their non-destructive character and the possibility to obtain absolute values of stresses in different phases of each type of crystal material (the measurements are performed selectively only for crystallites contributing to the measured diffraction peak, i.e. for the grains having lattice orientations for which the Bragg condition is fulfilled). In the frame of this work, the laboratory possibilities of the Institute of Aviation in this area are presented as well as the exemplary results of stress measurements performed there.

Schlüsselwörter

  • X-ray diffraction
  • residual stress measurements
  • fatigue
Uneingeschränkter Zugang

Preliminary Study of an Airplane for Electric Propulsion Testing at High Altitudes

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 167 - 174

Zusammenfassung

Abstract

Technology of photovoltaic cells and lithium batteries is being developed rapidly. As a result, attempts to build solar High Altitude Long Endurance (HALE) airplanes are more and more frequent. In the future, such airplanes may appear very useful for the economy because they may replace geostationary satellites in several applications. Unfortunately, data on altitude effect on photovoltaic cells and batteries performance are not easily available. Moreover, acquisition cost of cells is very high. Therefore, a tool for inexpensive testing of cells is needed. This article shows a study of very light unmanned airplane that could be used as a testbed for this purpose. Weight assumptions are presented together with concept of geometry and aerodynamic characteristics. Propulsion system is proposed, so also airplane performance is estimated. Finally, results are discussed leading to the conclusion. It appears that unmanned airplane with maximum take-off weight of 1.3 kg can climb to the altitude of 10 km within 4 hours during sunny summer day about the noon. However, only 30% of such days can be used because of strong winds blowing at high altitudes, quite small optimal airspeed of the airplane and constraints due to Air Traffic Management. Moreover, application of variable pitch propeller is recommended as well as some kind of take-off assist. For example, towing or take-off from the hill is desirable to avoid threats resulting from small climb rate.

Schlüsselwörter

  • Electric propulsion
  • flight testing
  • unmanned aerial vehicle
Uneingeschränkter Zugang

A Mobility Analysis of Using the Rhex-Type Mobile Robot in Various Surroundings

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 175 - 181

Zusammenfassung

Abstract

Mobile robots are becoming increasingly popular, finding a great deal of applications, especially in situations where conventional mobility systems, such as wheels or tracks, prove ineffective. Exploration of an unknown environment or a place, in which Man is incapable of staying, for example exploring remote planets in the Solar System, is often linked with operating a device in a rough terrain. This requires an adjustment of the robot locomotion system to the ground. The problem of high mobility in diverse surroundings is still a major challenge. Therefore, the concept of mobile robots is extremely popular and is still being developed. Using this type of propulsion carries several advantages, namely the possibility of applicability of this type of solutions in an environment, which is not easily accessible to wheeled vehicles (sandy, mountainous terrain, etc.). There is still a large interest of constructors and scientists in unconventional drive systems, adapted directly from nature, which often offers very efficient solutions. Quite frequently, designers copy the construction of animal locomotion system, attempting at implementing them in their designs. The aim of this article is to present an original construction, known as the Rhex-type robot in the available literature. In addition, it presents a number of conducted investigations, which describe the platform’s mobility in various terrains, such as sands, rocks and rubbles, as well as the possibility to overcome the terrain obstacles. It ends with conclusions and potential application areas of this type of a design.

Schlüsselwörter

  • mobile robot
  • Rhex
  • mobility
  • animal locomotion system
Uneingeschränkter Zugang

Android Application Used in Diagnostic System of Engineering Devices and Machines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 183 - 188

Zusammenfassung

Abstract

Users of machines and engineering devices force continuous improvement of their functionality and efficiency while reducing energy consumption. For this purpose, numerous sensors are installed in the machines in both drive systems and execution systems. Sensors are a source of information for control units and also allow reading parameters during diagnostic tests. The diagnostician should have the appropriate interface and knowledge of the operating principles of the tested machine. In order to facilitate the implementation of the diagnostic process even by less experienced service personnel, it is proposed to use a diagnostic interface based on the application developed in the Android system, which main element is a QR code scanner. The system uses MATLAB-Simulink, database and PHP script to work properly. This system allows performing a diagnostic test and identifying potential causes of device failure. The system has friendly interface where is implemented many useful things like graphs and visualization of device movement. The application reads the nominal operating parameters stored in the QR code of the machine and displays the next steps necessary to assess the technical condition of the object. On the basis of a comparison of registered and nominal machine parameters, the application indicates possible fault locations. The implementation of the database on an external server allows the application to run anywhere on android devices that have access to the internet. Through the registration process, it is possible to create a database of employees who have access to the system. The diagnostic system for storing all information, such as employee data or current sensor measurement values uses the MySQL database. Preliminary tests of the application carried out during diagnostics of the hydraulic and mechanical system of the building manipulator confirmed the functionality of the developed system.

Schlüsselwörter

  • QR code scanner
  • diagnostic interface
  • MySQL database
  • hydraulic manipulator
Uneingeschränkter Zugang

Comparative Analysis of NEDC and WLTC Homologation Tests for Vehicle Tests on a Chassis Dynamometer

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 189 - 196

Zusammenfassung

Abstract

In 2015, the number of vehicles in the world exceeded 1.1 billion units. In the coming years, it is expected that the largest increase in the number of vehicles will take place in developing countries. This is a problem in particular in terms of emissions of harmful substances from vehicles. Considering that all manufactured vehicle models have to undergo a detailed homologation and meet the exhaust emission requirements before placing on the market, it is necessary to refine test procedures, including test cycles, in which vehicle emissions are determined. At present, the NEDC approval test is valid in Europe. It is a cycle reproduced on a chassis dynamometer in steady conditions. It consists of an urban section repeated four times and an extra urban part. From 2019, a new test procedure will take effect, which uses the WLTC cycle, also reproduced on a chassis dynamometer in fixed conditions. It is much more complex and better reflects the real traffic conditions. For a better illustration of the differences that occur between the current NEDC cycle and the new WLTC, the article presents a comparative analysis of both driving cycles. This is to present the justifiability of using a new driving cycle and to present its complexity. The article presents own research of a vehicle with a spark-ignition engine, which has been tested both in the NEDC and WLTC cycle. On the basis of the obtained data, it was possible to determine the differences in the emission of harmful exhaust gas components and indicate how the new homologation procedure affects the emissions from the vehicle.

Schlüsselwörter

  • combustion engines
  • homologation procedure
  • NEDC test
  • WLTC test
  • exhaust emissions
Uneingeschränkter Zugang

Possibilities of Using a Wireless Telemetry System of a Recreational Vehicle (Off-Road)

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 197 - 203

Zusammenfassung

Abstract

The development of electronic systems has significantly contributed to the rapid increase in the number of controllers working in vehicles, and thus the amount of data transferred between them. The large amount of information sent prevents the driver from directly mastering or understanding them, hence it was necessary to limit the displayed parameters on the instrument cluster to the most important ones, so that the driver can focus on driving. However, in motor sports and in various types of road tests or research, where the driver is supported by an additional team of engineers, information sent between vehicle controllers can prove extremely valuable. Most often, the whole staff of people responsible for conducted traction tests does not occupy the vehicle, so as not to disturb the conditions. Their analysis usually takes place in a designated service spot, in which case the parameters from the on-board data transmission network are usually transmitted by radio from the vehicle to the archiving system. Therefore, research into the development of wireless data transmission systems from vehicle controllers is also carried out at the Opole University of Technology. This article describes the possibilities of using a system built at the Opole University of Technology for wireless conduction of diagnostics and analysis of current operating parameters of a recreational All-Terrain Vehicle (ATV). In addition, in the designed system, it is also possible to connect external sensors to analyse parameters normally not registered during the course on normal vehicle operation.

Schlüsselwörter

  • telemetry
  • wireless data acquisition
  • all-terrain vehicle
  • CAN bus
Uneingeschränkter Zugang

Flame Propagation in Gas Feeding Pipelines to the IC Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 205 - 212

Zusammenfassung

Abstract

Results from experimental investigation on flame propagation in a pipeline filled with gaseous combustible mixture consisted of hydrogen, methane or 20% hydrogen-methane is presented in the article. The mixture was prepared in separate cylinders and premixed before filling the pipeline. The tests were conducted under various relative equivalence ratio – lambda from 1.0 to 3.0 at pressure of 1 bar and temperature of 25ºC. Hydrogen and methane were selected because these gases are main combustible fractions in several gaseous engine fuels (e.g. natural gas, syngas, biogas). Additionally, the mixture 20% hydrogen and methane, as potential engine fuel, was also under investigation. Flame front was detected with aid of IR photodetectors. Hence, the flame speed was resulted from distance divided by time. As observed, the flame propagation speed was over 100 m/s for both hydrogen and methane premixed mixtures. It was several times higher if compared with the laminar flame speed for these gases. It can be explained by additional acoustic effects (standing waves) taking place inside the pipeline. Results from this investigation can be useful in design and construction of the gas feeding system in the gas fuelled internal combustion engine.

Schlüsselwörter

  • flame propagation
  • laminar flame speed
  • methane
  • hydrogen
  • combustion
Uneingeschränkter Zugang

Issues during Assembly New Type of Electric Brake Prototype and Initial Tests of Individual Components

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 213 - 218

Zusammenfassung

Abstract

In this article, the author focused on the two main issues. Firstly, the assembly phase of the new type of electric brake prototype was described and secondly author introduced the initial tests of individual components. The assembly phase of the new prototype of the electric brake was very significant. In this stage, the parts were fitted and mounted. The new functionality of new type prototype was checked and the designing was verified. If there were some mounting problems this was proper time to correct the dimensions and exchange parts. Sometimes the materials or even or heat treatment of some part were exchanged. In that kind of prototype, it was really important to check electric parts like motors during the load. The most important issue was to find the best solution. The motors weight should have been as small as possible and the nominal torque should have been enough for normal working of prototype. In the initial tests of individual components, the real parameters were tested and possibility of using the parts was checked too. During designing phase, the parameters were defined and the tests results gave the answers for the possibility of real working on the object. The most important parameters there were the motors parameters and the possibility of mechanism force transmission.

Schlüsselwörter

  • assembly
  • electric brake
  • prototype
  • mounting
  • new designing
Uneingeschränkter Zugang

Resistance to Aging Research in Sea Water Composites with the Polyester-Glass Recyclate

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 219 - 225

Zusammenfassung

Abstract

Composites are materials used for various types of constructions in the automotive industry, aviation, and shipbuilding. Due to the wide use of these materials, there is a problem with their recycling. Such material requires appropriate processing technology, which has been developed to obtain a recyclate with a specific granulation. The use of hand laminating technology made composites with the addition of polyester and glass recyclate with granulation of 1.2, as well as content: 0%, 20%, 30%. These types of materials are exposed to various types of atmospheric factors that affect their durability. Aging is defined as changes in the composite when exposed to atmospheric conditions, such as sunlight, temperature, thermal cycles, water in various forms and wind. This article uses recycled polyester and glass composites to investigate the effect of aging in seawater on their strength properties. These tests can be used to pre-assess the applicability of newly developed materials as construction or protective coatings. They were carried out on a specially prepared station for accelerated tests, with elevated temperature (35ºCC), as well as brine spray imitating sea atmosphere. The method is used to accelerate the aging processes occurring in composite materials. Samples were subjected to cycles of 5, 30 and 60 days respectively. Samples were weighed and measured before and after each cycle. In order to investigate the effect of aging on strength properties, the composites underwent a static tensile test in accordance with the standard for plastics. Studies have shown that as a result of the aging process, the strength properties decrease slightly, which affects the favourable assessment of these materials as constructional.

Schlüsselwörter

  • recycling
  • polyester-glass recyclate
  • aging of composites
  • tensile test
Uneingeschränkter Zugang

Laminar Burning Velocity Predictions of Single-Fuel Mixtures of C1-C7 Normal Hydrocarbon and Air

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 227 - 235

Zusammenfassung

Abstract

The numerical modelling of combustion phenomena is an important task due to safety issues and development and optimization of engines. Laminar burning velocity (LBV) is one of the most important physical properties of a flammable mixture. Knowing its exact value if crucial for assessment of flame stabilization, turbulent flame structure. It influences strongly safety, probability of knocking combustion and it is one of parameters used for assessment and development of detailed chemical kinetic mechanisms. Hence, the goal of this work is to develop models by means of Machine Learning algorithms for predicting laminar burning velocities of single-fuel C1-C7 normal hydrocarbon and air mixtures. Development of the models is based on a large experimental data set collected from literature. In total more than 1000, LBVs were accumulated for hydrocarbons from methane up to n-heptane. The models are developed in MATLAB 2018a with use of Machine Learning toolbox. Algorithms taken into account are multivariate regression, support vector machine, and artificial neural network. Performance of the models is compared with most widely used detailed chemical kinetics mechanisms’ predictions obtained with use of LOFEsoft. These kind of models might be efficiently used in CFD combustion models based on flamelet approach. The main advantage in comparison to chemical kinetics calculation is much shorter computational time needed for computations of a single value and comparable performance in terms of R2 (coefficient of determination), RMSE (root-mean-square error) and MAE (mean absolute error).

Schlüsselwörter

  • laminar burning velocity
  • hydrocarbon
  • machine learning
  • LOGEsoft
  • alkane
  • MATLAB
Uneingeschränkter Zugang

Modelling of the Over-Expanded Cycle Combustion Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 238 - 245

Zusammenfassung

Abstract

The study concerns numerical tests of an internal combustion engine operating according to the over-expanded cycle carried out in the AVL Fire software. The research covered the modelling of a full working cycle of a conventional engine operating in accordance with the classic Otto cycle and an engine operating on the basis of an over-expanded cycle – the Atkinson cycle. As part of the work, three cases of Atkinson’s cycle were analysed, by closing the inlet valve before BDC (21º before BDC) and closing the valve after BDC (41º and 75º after BDC). As a result of modelling, space-time distributions of velocity, pressure and temperature in the cylinder of the modelled engine were obtained. Optimizations of the analysed cycles were carried out, finding the best ignition timing, at which it is possible to obtain the highest efficiency and the highest indicated mean effective pressure. The calculations showed that the engine operating according to the over-expanded cycle in order to obtain the best operating parameters requires earlier ignition timing compared to the conventional engine. In addition, in the engine operating according to the Atkinson cycle, there is a drop in the indicated mean effective pressure and an increase in the indicated thermal efficiency compared to the engine operating by the classical cycle.

Schlüsselwörter

  • over-expanded cycle
  • methane
  • gas engine
  • modelling
Uneingeschränkter Zugang

Numerical Analysis of a Velocity Distribution of a Fluid Flow Inside a Reversing Chamber

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 247 - 251

Zusammenfassung

Abstract

Axisymmetric stream, which is directed into an obstacle, is an important type of a fluid flow for technical applications in a large amount of thermal and flow devices. The article presents a case wherein stream of a fluid is directed into a flat surface and changes the direction of a flow by an angle equal to 90°. After that, the free stream is changing a character of a flow into impinging stream. The article presents a methodology of numerical calculations preparation in ANSYS Fluent environment for a velocity distribution of an airflow inside a reversing chamber. Numerical calculations were prepared for a three-dimensional model as an unsteady simulation with Delayed Detached Eddy Simulation model of turbulence. A stream of an air, which was analysed inside a reversing chamber, was not initially swirled. Obtained results of realized calculations were compared with experimental analysis and numerical calculations, which was realized in a different environment by co-author. Model of reversing chamber, which was implemented into numerical analysis has the same dimensions as used in experimental research. Obtained results show areas of intense flow turbulence inside reversing chamber. Prepared numerical calculations agreed with experimental results of research and allowed to designate areas of stream core and impinging stream inside modelled chamber.

Schlüsselwörter

  • numerical analysis
  • reversing flow
  • fluent
  • axisymmetric flow
Uneingeschränkter Zugang

In-Cylinder Combustion Analysis of a SI Engine Fuelled with Hydrogen Enriched Compressed Natural Gas (HCNG): Engine Performance, Efficiency and Emissions

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 253 - 260

Zusammenfassung

Abstract

The main objective of this study was to investigate the effect of hydrogen addition on spark ignition (SI) engine’s performance, thermal efficiency, and emission using variable composition hydrogen/CNG mixtures. The hydrogen was used in amounts of 0%, 20%, 40% by volume fraction at each engine speed and load. Experimental analysis was performed at engine speed of 1200 rpm, load of 120 Nm corresponding BMEP = 0.24 MPa, spark timing 26 CAD BTDC, and at engine speed of 2000 rpm, load of 350 Nm corresponding BMEP = 0.71 MPa, spark timing 22 CAD BTDC. The investigation results show that increasing amounts of hydrogen volume fraction contribute to shorten ignition delay time and decrease of the combustion duration, that also affect main combustion phase. The combustion duration analysis of mass fraction burned (MFB) was presented in the article. Decrease of CO2 in the exhaust gases was observed with increase of hydrogen amounts to the engine. However, nitrogen oxides (NOX) were found to increase with hydrogen addition if spark timing was not optimized according to hydrogen’s higher burning speed.

Schlüsselwörter

  • Hydrogen
  • CNG
  • SI engine
  • combustion
  • emission
  • MFB
Uneingeschränkter Zugang

Combustion of RME – Diesel and NExBTL – Diesel Blends with Hydrogen in the Compression Ignition Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 261 - 274

Zusammenfassung

Abstract

The article presents the test results of the single cylinder compression ignition engine with common rail injection system operating on biofuels and conventional diesel blends with hydrogen. Two types of liquid fuels were tested: blend of the 7% Rapeseed Methyl Ester (RME) with conventional diesel fuel and Neste Pro Diesel – blend of the 15% Hydrotreated Vegetable Oil (HVO), produced by Neste Oil Corporation with conventional diesel fuel. The purpose of this investigation was to examine the influence of the hydrogen addition to biofuels and diesel blends on combustion phases, autoignition delay, engine performance efficiency and exhaust emissions. Hydrogen fraction was changed within the range from 0 to 43% by energy. Hydrogen was injected into the intake manifold, where it created homogeneous mixture with air. Tests were performed at both fixed and optimal injection timings at low, medium, and nominal engine load. After analysis of the engine bench tests and simulation with AVL BOOST software, it was observed that increasing hydrogen fraction shortened the fuel ignition delay phase and it affected the main combustion phase. Moreover, decrease of carbon monoxide (CO), carbon dioxide (CO2) and smoke opacity was observed with increase of hydrogen amounts to the engine. However, increase of the nitrogen oxide (NOx) concentration in the engine exhaust gases was observed.

Schlüsselwörter

  • hydrogen
  • RME
  • HVO
  • NExBTL
  • PRO Diesel
  • diesel fuel
  • CI engine
  • combustion
  • emission
Uneingeschränkter Zugang

Mechanical and Thermal Stresses Issues Related to a Size of a Four-Stroke Piston Based on a Renault Premium DXi11 430 460 EEV Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 275 - 282

Zusammenfassung

Abstract

The size of an engine is one of the factors affecting its thermal efficiency. It is known that with an increase of the size of the engine, the cubic capacity and heat generation grows in the third power, whereas thermal losses are proportional only to the second power of the size (due to heat exchange surface). However, the increase in the size of the engine generates some problems related to its mass, rotational speed and heat load, the last of which is a subject of these considerations. In the article, the influence of the piston size on its thermal and mechanical stresses is considered. Similar boundary conditions for both cases were assumed. Simulation of the steady-state heat transfer and mechanical simulation were carried out using the Finite Element Method. In each analysis, both the original version of the piston and its scaled version were considered. The boundary conditions were adopted on the basis of engine catalogue data and available literature. The results of analyses were discussed.

Schlüsselwörter

  • heat transfer
  • temperature distribution
  • four-stroke engine piston
  • finite element method
  • size related issues
Uneingeschränkter Zugang

The Influence of Injection Timing on the Combustion Characteristics for the Heterogeneous Combustion Field Using Impinging Injection

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 283 - 288

Zusammenfassung

Abstract

It is very important to achieve the low particulate and low emissions under high power operation conditions in practical industrial engine and turbine combustion. Several techniques for reducing the emissions have been proposed and a large amount of experimental data has been published. It is well known that the combustion field in practical industrial diesel engine are strongly influenced by the behaviour of injection, distribution of droplets and the premixed ratio of the combustion chamber. As the first step of this study, experiments have been carried out to examine the combustion characteristics of heterogeneous combustion field by using impinging injection and Split injection in a closed chamber. The combustion chamber is equipped with pintle type injection nozzles on each of the opposite walls along the length of the bomb. In this study, we call it “impinging injection” when the injection is performed at same time by two nozzles facing each other and “split injection” when the impinging injection is performed at two different timing. The main conclusions are as follows: 1) the most suitable conditions of injection timing exists for improving the maximum burning pressure and total burning time by using impinging injection; 2) the flame speed can be possible to control by using impinging injection timing from the ignition; 3) the heat release rate for Split injection is larger than that of standard impinging injection.

Schlüsselwörter

  • impinging injection
  • split injection
  • heat release rate
Uneingeschränkter Zugang

Selected Aspects of the Maintenance System Optimisation of the Polish Armed Forces Helicopters

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 289 - 297

Zusammenfassung

Abstract

The maintenance of helicopters at the airports of the Polish Armed Forces in the state of technical efficiency determines the possession – by the entity securing their maintenance, repair – of appropriate resources and the maintenance system. The article presents the current state of the operation processes of helicopters in the Polish Army. The characteristics of the helicopter maintenance system model and the basic assumptions were described, and the mathematical records of input data to the system were identified and presented. The selected elements of the optimisation task, its decision variables, and constraints were formulated. The initial assessment of the quality of the proposed solution of the helicopter maintenance system model. The essence of the system optimisation problem, which relates to minimising the cost function and maximising the system’s readiness function, was emphasised. In addition, an example of appropriateness of applying such an approach is presented on the basis of the School Aviation Base. The article was concluded with a short summary, which stressed the importance of this type of the optimisation system.

Schlüsselwörter

  • helicopters
  • maintenance system
  • optimisation of systems
Uneingeschränkter Zugang

Automatic Taxi Directional Control System for General Aviation Aircraft

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 299 - 306

Zusammenfassung

Abstract

The article presents a concept of an automatic directional control system for a General Aviation class aircraft during the taxiing phase. In particular, it shows the concept of the system and the control laws synthesis – mathematical model and simulation of taxiing aircraft. Several reasons have emerged in recent years that make the automation of taxiing an important design challenge including decreased safety, performance and pilot workload. The adapted methodology follows the model based design approach in which the control system and the aircraft are mathematically modelled to allow control laws synthesis using the Adaptive Disturbance Rejection Control method. The computer simulations are carried out to analyze the control system behavior. Chosen methodology and modelling technique, especially tire-ground contact model, resulted in a taxing aircraft model that can be used for directional control law synthesis. Aerodynamic forces and moments were identified in the wind tunnel tests for the full range of the slip angle. The results can be used for the preliminary performance assessment of the ADRC method applied in the taxi directional control system. Such system has not been introduced to General Aviation yet. Therefore, the model of taxiing aircraft including aerodynamic characteristics for the full range of the slip angle and a directional control system have a big value in the process of design and implementation of the future automatic taxi systems.

Schlüsselwörter

  • General Aviation
  • taxiing
  • automatic control
  • mechanics of flight
  • aerodynamic tests
Uneingeschränkter Zugang

The Use of Fuzzy Expert System for an Automatic Control of the Propulsion System in the Aircraft Zlin 143LSi

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 307 - 314

Zusammenfassung

Abstract

The article discusses the manner of controlling the propulsion system in the aircraft Zlin 143LSi, which is equipped with a piston engine driving a variable-pitch propeller. All the operating procedures are carried out manually by the pilot in accordance with the flight manual. The authors attempted at developing the project of a controller based on fuzzy logic, whose main goal was automating the control system of the propulsion unit, thus lowering the level of difficulty of pilotage, and increasing the economics of the operation. The project was made in an interactive environment FuzzyLogic Toolbox of the MATLAB programme. In the analysis, three input parameters were taken into account, exerting an impact on changing the rotational speed of the propeller: the charging pressure of the propulsion unit expressed in inches of mercury, the speed of the aircraft (TAS) in knots and the angle of attack, at which the flight is made, expressed in degrees. On the basis of the above-mentioned input signals, the rotation speed of the propeller was determined, by changing the blade pitch and the recommended angle of attack for the parameters in order to make an optimal use of the data of the flight conditions. The article presents the project of the controller and its optimization. The authors simulated the controller operation in the package MATLAB “Simulink”. The article ends with data analysis and final conclusions.

Schlüsselwörter

  • fuzzy logic
  • fuzzy expert system
  • propulsion system
  • aircraft Zlin 143LSi
Uneingeschränkter Zugang

Necessary Wind Tunnel Tests Conditions of Proper Two- and Three-Dimensional Measurements

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 315 - 322

Zusammenfassung

Abstract

In this article, the conditions to be met by a two- and three dimensional wind tunnel tests in order to ensure their correctness are presented. First of all, they relate to the flow similarity between the real and wind tunnel conditions. This similarity enforces a wind tunnel calibration, a proper design and manufacturing of the tested models, a proper research, as well as processing of obtained test data including the usage of the wind tunnel corrections. In this work, the majority of these conditions were presented but in particular, the influence of the wind tunnel corrections on the tested models aerodynamic characteristics is consider. The two-dimensional airfoil studies and three-dimensional aircraft model balance investigation were performed in two low speed wind tunnels of a different sizes of theirs test section. The wind tunnel tests were performed in two Institute of Aviation low speed wind tunnels, namely in the wind tunnel T-1 (of the 1.5 m diameter test section) and in the wind tunnel T-3 (of the 5 m diameter test section), at the same undisturbed velocity, V∞ = 40 m/s. The comparison of the lift coefficient characteristic obtained in two different wind tunnels using the same two and three-dimensional models and same measurement techniques enabled to discuss the problem of necessity of the wind tunnel corrections usage.

Schlüsselwörter

  • applied aerodynamics
  • tests reliability
  • aerodynamic measurements
Uneingeschränkter Zugang

The Evaluation of the Fiat 0.9 TwinAir Engine Powered by Petrol and LPG Gas Work Cycles Uniqueness

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 323 - 330

Zusammenfassung

Abstract

The article describes the test results of the uniqueness of the work cycle of two-cylinder internal combustion piston FIAT 0.9 TwinAir engine, while being powered by 95 octane petrol fuel and LPG gas. The engine was working according to load characteristics. The engine mounted on the test bench was equipped with a sequential LPG gas fuel supply system. The gas fuels differ significantly from the petrol fuels in their physiochemical properties. In order to rationally utilize gas fuels to power internal combustion engines, the knowledge about basic fuel burning process of these fuels is required. The article shows the analysis of individual engine work cycles of the technologically advanced engine in order to evaluate the influence of powering by LPG gas fuel on the rate of uniqueness of its work cycles. The measure of uniqueness of the inter-cylinder processes are the work cycle uniqueness indicators, which are as follows: the maximum work cycle pressure uniqueness indicator, the average measured work cycle pressure uniqueness indicator, the measured pressure work cycle graph uniqueness indicator and the measured pressure work cycle partial graph uniqueness. The carried out research and its analysis has shown that powering the engine with LPG gas has an influence on the engine work cycles and its uniqueness. The burning process of the mixture consisting of air and LPG gas is quicker, which has an effect on the higher speed of pressure increase rate in comparison with the engine being powered by petrol fuel. Achieved maximum in-cylinder pressure values while the engine was powered by LPG gas were higher in comparison with it being fuelled with conventional fuel. This causes an increase of the gas lads on crank-piston system, which are influencing directly the piston with higher heat load, and the thermal load of the engine.

Schlüsselwörter

  • spark ignition engines
  • gas engines
  • gasoline engines
  • uniqueness of work cycle of internal combustion engine
  • indicator diagram
Uneingeschränkter Zugang

Application of Similarity Method of Distance Courses Describing the Elements Content in Cement Concrete after Frost Resistance Test

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 331 - 337

Zusammenfassung

Abstract

The work concerns test results of cement concrete and the use of similarity analysis of distance course. Research procedure was presented and the obtained laboratory tests results were discussed. Composition of concrete mixes was designed. The cement concrete composition includes cement, coarse aggregate, fine aggregate, water, admixtures and a ceramic addition. The addition of ceramic was used as a replacement for part of the fine aggregate Fresh concrete mixture parameters were tested and basic parameters of hardened concrete were defined (density, compression strength and tensile strength). The scope of works included concretes intended for airfield pavements and this concretes after frost resistance test. The test has been conducted in diversified media generally used in the course of winter maintenance. Subject to observations of internal structure of concretes and conducted chemical microanalyses using scanning electron microscope, the contents of diversified elements in four zones were specified. The following zones were subject to analysis: cement matrix, contact area between air pores and cement matrix, contact area between fine aggregate and cement matrix and contact area between coarse aggregate and cement matrix. Based on the results obtained diagrams similarity of the analysed concretes were prepared.

Schlüsselwörter

  • airfield pavements
  • cement concrete
  • ceramic additive
  • frost resistance
  • analysis of similarity
Uneingeschränkter Zugang

Device for Control the Valvetrain and Cylinder Pressure of a Spark-Ignition Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 339 - 346

Zusammenfassung

Abstract

This article describes the method of controlling an electric magnetic linear actuator that moves an inlet valve of an internal combustion engine. Thanks to the use of the electric control of the inlet valve of the internal combustion engine, it was possible to implement a variable effective compression ratio of the operating power unit, adapting it to the current needs and engine load. In this design, valvetrain was modified by introducing an autonomous intake valve operation with the use of a specially designed electromagnetic actuator. The introduction of this system necessitated an additional modification of the intake camshaft. The control was carried out with the use of a real-time controller with a built-in FPGA unit. The proposed design of a system with an electromagnetic actuator will allow obtaining an additional degree of freedom in the control unit. Particular attention should be paid to registered values or air pressure in the intake stroke for a closed or partially opened throttle, which generates significant pumping losses. The use of an electromagnetic actuator in the intake can help reduce said losses.

Schlüsselwörter

  • combustion engines
  • environmental protection
  • variable compression ratio
  • valve control
Uneingeschränkter Zugang

Preliminary Analysis of Thermodynamic Cycle of Turbofan Engine Fuelled by Hydrogen

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 347 - 354

Zusammenfassung

Abstract

Presented article is focus on analysis of the effect of hydrogen fuel on turbofan engine performance. Selected properties of hydrogen and possibility of introduction in civil aviation were discussed. Hydrogen implementation as aviation fuel offers obvious advantages such as low emission of combustion product, higher payload, lower fuel consumption, general availability but also poses great technical challenges. The most important aspect is to ensure engine operational safety at very high level. Hydrogen implementation would eliminate the aviation dependence of exhausting sources of fossil fuels especially of crude oil. The thermodynamic model of turbofan engine was implemented in MATLAB environment. Accepted assumptions have been discussed. Turbine cooling process has been included in the numerical model. Working fluid was modelled as semi-perfect gas. Analysis was carried out for take-off and design point conditions. Engine performances were compared for two kinds of applied fuels: liquid hydrogen and commonly used in turbine engines kerosene. Combustion heat of hydrogen is about three time higher than in comparison with conventional turbine engine fuel, what exert significant influence on engine performance. The results of engine thermodynamic cycle analysis indicate the increase in specific thrust and significant reduction of specific fuel consumption. The results are presented in tabular form and on the graphs. Obtained results have been discussed and the direction of further research was indicated.

Schlüsselwörter

  • liquid hydrogen
  • turbofan engine
  • turbine cooling
  • engine thermodynamic cycle
  • engine performance
Uneingeschränkter Zugang

Analysis of the Influence of the Changes in the Value of Dynamic Viscosity Coefficient in the Direction of Oil Film Thickness on the Journal Bearing Load Carrying Capacity

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 355 - 362

Zusammenfassung

Abstract

This article presents the results of numerical calculations of the hydrodynamic pressure distribution, load carrying capacity, friction force and friction coefficient of the slide journal bearing, if the assumed model of hydrodynamic lubrication takes into account the dependence of oil viscosity values on its temperature in all three directions of the adopted coordinate system, in particular, also across the thickness of the lubricant layer. This research considered the slide journal bearing lubricated with the Newtonian oil. The flow of oil was modelled as laminar and stationary. The bearing bushing had a full angle of wrap and its surfaces were smooth. In order to obtain hydrodynamic pressure distributions, the Reynolds type equation was numerically solved by application of the finite difference method (FDM). The numerical procedures for this research were prepared with the Mathcad 15 software. When adopting the classic models and simplifications for the hydrodynamic lubrication and a thin boundary layer, it is assumed, that the hydrodynamic pressure of lubricating oil does not depend on the position measured across the height of the lubrication gap. On the other hand, it is known, that the dynamic viscosity strongly depends on the temperature, which is a function of all three spatial variables. The aim of this work is to include, in the hydrodynamic lubrication model, the changes of viscosity in the direction of oil film thickness, and to investigate how it will affect the hydrodynamic pressure distribution and load carrying capacity of the journal bearing.

Schlüsselwörter

  • slide journal bearing
  • load carrying capacity
  • friction force
  • friction coefficient
  • numerical calculation
Uneingeschränkter Zugang

Measurement of Axial Motions of Piston Rings in a Two-Stroke Engine by Using Back Light of LED

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 363 - 369

Zusammenfassung

Abstract

In two-stroke engines of the crankcase-compression type, the piston rings slide over not only the cylinder wall but also the cylinder ports. It is important for piston ring designers to understand how piston rings behave over cylinder ports. In order to clarify the axial motion of piston rings in two-stroke engines, we established a measurement method using light-emitting diodes (LEDs). We attached LEDs inside the piston, and leaked the backlight of LEDs through the side clearance between the piston ring side face and the piston ring groove side face. From the position of the leaked backlight in the piston ring groove, we determined the axial ring position in the ring groove. Our experiments set this piston with LEDs in an experimental two-stroke engine with a transparent cylinder, and investigated the effects of intake and exhaust ports on axial ring motion under motoring operations. Results indicated that the rings moved in the axial direction by the ring projection and catching in the intake and exhaust ports.

Schlüsselwörter

  • two-stroke engine
  • piston ring
  • cylinder port
  • axial motion of piston ring
  • LED
  • transparent cylinder
Uneingeschränkter Zugang

Analysis of the Wind Dependent Duration of the Cruise Phase on Jet Engine Exhaust Emissions

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 371 - 376

Zusammenfassung

Abstract

Nowadays more and more attention is paid to minimizing the costs of air operations. The largest share in the cost of the flight is the cost of consumed fuel. Taking into account the external conditions, having impact on the aircraft, such as wind direction and magnitude when planning the aircraft trajectory it is possible to reduce flight time and thus reduce fuel consumption. An additional advantage is the simultaneous reduction of pollutants in the jet engines exhausts. In the times of pro-ecological trends and concepts (e.g. Clean Sky, Single European Sky, CORSIA) this aspect is of crucial importance. The emission of selected pollutants in the jet engine exhausts (NOx, CO and HC) emitted during the flight of a business jet on the route whose cruise phase was assumed 1000 km long was determined in the article. The aircraft used in the research was Gulfstream GIV, powered by two Rolls Royce TAY 611-C engines, for which a cruising altitude of 10 km and a flight speed of 0.8 Ma were assumed. The thrust necessary for the flight at these cruise parameters was set, and then the engine thrust appropriate for the flight and the corresponding specific fuel consumption were determined. On this basis, based on the available ICAO data, the emission of selected pollutants in tis engines exhausts was determined for windless conditions. Next, the analysis of the impact of wind - its magnitude and direction – on the emission of these pollutants was made. The results of the conducted analyses are presented in diagrams and discussed in the conclusions.

Schlüsselwörter

  • air transport
  • jet engines
  • air pollution
  • emission
  • exhausts
  • wind impact
Uneingeschränkter Zugang

The Importance of Mixture Preparation for Industrial Heat and Power Gas Engines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 385 - 392

Zusammenfassung

Abstract

The main task of a gas mixer is to mix the fuel (gas) with air in such a way that in the gas engine optimal combustion takes place. A high efficiency of the whole combustion process and low emissions are the decisive optimization parameters. An industrial gas engine operates mostly with a lean air-gas combustion mixture with an air excess coefficient ratio of → λ=1.6. Most often heat and power industrial gas engines operate with biogas. The biogas is produced by anaerobic digestion, where biodegradable materials in the absence of oxygen are fermented. That is why the biogas fuel consists mostly of methane → CH4 (up to 70 [%]), carbon dioxide → CO2 and traces of other contaminant gases. It is well known, that the performance of industrial gas engines strongly depends on the quality of air and fuel mixing and therefore homogeneity of the mixture. Improper air-gas mixture can lead to unstable operation of the entire gas engine and excessive emissions beyond the applicable environmental standards. Therefore, in this article numerical investigations were performed using the open source computational fluid dynamics software OpenFOAM to show the importance of mixture preparation for industrial heat and power gas engines by describing in detail the mixing behaviour in a Venturi gas mixer model.

Schlüsselwörter

  • gas engine
  • environmental friendly power generation
  • combustion processes
  • mixture preparation
Uneingeschränkter Zugang

Experimental Studies of Leading Edge Vortex Control of Delta Wing Micro Aerial Vehicle

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 393 - 402

Zusammenfassung

Abstract

It is known, that small disturbances generated by the micro actuators can alter large-scale vortex structures, and consequently, generate appreciable aerodynamic moments along all three axes for flight control. In the current study, we explored the possibility of independently controlling these moments. We perform analytical simulations showing optimal position of LEX generators, and water tunnel measurements showing effectiveness of MEX generators as MAV control devices. We applied array of actuators located on either the forward or the rear half section of the leading edge. Both one- and two-sided control configurations have also been investigated. Experimental results showed that asymmetric vortex pairs were formed, which leads to the generation of significant torques in all three axes. The article presents typical vortical flow over a delta wing, water tunnel at Wroclaw University of Technology, experimental setup and procedures, static test results on water tunnel testing including normal forces, pitching and yawing moments, maximum values of rolling, pitching, and yawing moment coefficients, effectiveness of pitching and yawing control.

Schlüsselwörter

  • Micro Aerial Vehicles
  • Unconventional control effectors
Uneingeschränkter Zugang

A Method of Engines’ Diagnosis in Operation

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 403 - 410

Zusammenfassung

Abstract

It was found that there are discrepancies between the values of diagnostic parameters obtained in the test and natural exploitation. In addition, no appropriate tests are carried out which would be based on the degree of engine degradation in long-term natural use. One of the reasons is the lack of adequate, non-invasive diagnostic methods. The aim of the work was to show the possibility of creating a new diagnostic parameter of combustion engines in their natural operation. The parameter can be determined by a new method (presented in the article). The method is based on the assumption that the technical condition of the engine can be judged on the basis of the run-up curve, and in particular, on the basis of the linear direction coefficient, which is approximated by the points of the run-up curve at particular moments of the run-up. An additional requirement is that the points of the run-up curve are the average value of the speed from many runs. In addition, the statistical distributions of the speed values in the individual moments of the run-up should be of the same type. The direction coefficient of the straight line determined is a diagnostic parameter. The value of the new coefficient is the value of the straight-line factor. Further works are underway to determine the relationship between the directional coefficient and the technical condition of the engine.

Schlüsselwörter

  • transport
  • combustion engine
  • engine diagnostic
  • diagnostic methods
  • engine technical conditions
Uneingeschränkter Zugang

Influence the Applied Control Structure on Energy Efficiency of the Hydrostatic System

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 411 - 418

Zusammenfassung

Abstract

A control system with a proportional directional throttling control valve or a directional control servo valve, controlling a cylinder (linear hydraulic motor) is used in the ship steering gear drive, in the controllable pitch propeller control, in the variable capacity pump control system for hydraulic deck equipment motors or fixed pitch propellers in small ships (for example ferries). The hydraulic system is designed first of all taking into consideration the nominal parameters of the cylinder load and speed. For such parameters, the energy efficiency of the elements and complete system is described. Meanwhile the exploitation conditions can vary in full range changes of the cylinder load and speed coefficients. The article presents a comparison of the energy behaviour of two widespread structures of hydrostatic systems: a standard individual systems with a throttling steering fed by a constant capacity pump. Both hydraulic solutions are described and equations of the total efficiency η of the system are presented. Diagrams of energy efficiency of two hydraulic systems working at the same parameters of a speed and a load of hydraulic linear motor, which were different due to structure are presented and compared, as well ability of energy saving. This publication also presents analyses and compares the areas of the power fields of energy losses occurring in the elements of two hydraulic systems with different structures of the hydraulic linear motor speed control.

Schlüsselwörter

  • energy efficiency
  • power of losses
  • hydrostatic system
  • throttling steering
  • pump
  • hydraulic linear motor
  • proportional directional valve
  • deck machinery
Uneingeschränkter Zugang

Research on the Effect of Diesel Fuel Injection Parameters on the Combustion Process in the Turbocharged CI Engine Operating on Propane

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 419 - 429

Zusammenfassung

Abstract

Results presented in the article regard the research on a turbocharged dual-fuel CI engine operating on propane. The research indicated that such engine might operate even if 70% of the standard fuel energy is replaced by propane. The research indicated that at such high share of the gaseous fuel, there is necessary to adjust diesel fuel injection parameters but it is important that there is no need to change the engine structure. Injection parameters may be adjusted in a wide range due to the modern fuelling system of the common rail type. The investigated engine was equipped with such system. Adjustments regarding the fuel charge division, fuel charge quantities, and injection timing enabled to influence combustion in such way to obtain its specific parameters, i.e. maximum combustion pressure, rate of pressure rise, maximum pressure, and the burn out ratio similar to those obtained for diesel fuel operation. The obtained results were presented in form of adjustment characteristics of the injection timing of diesel fuel pilot dose for a few chosen values of the boost pressure as well as injection timing of the main dose. The investigations were carried out for three values of the boost pressure, i.e. 200; 400 and 600 [mbar] but also for the naturally aspirated version. Injection timing of the first dose varied in a broad range and depended on the boost pressure. Injection timing of the second dose varied in a narrower range, mainly due to considerable changes in the combustion process. The obtained results answered a number of questions regarding the strategy of selection of diesel fuel injection parameters taking into consideration engine performances as well as combustion at a high share of the gaseous fuel.

Schlüsselwörter

  • combustion engines
  • dual fuel
  • propane
  • control of injection parameters
Uneingeschränkter Zugang

LoRaWAN Networks in Automotive Applications

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 431 - 435

Zusammenfassung

Abstract

Development of IoT is tightly coupled with the use of the wireless communication solutions. Nowadays there are several standard wireless protocols, which are responsible for carrying information. The increase of the communication traffic tends to specialize the kind of used data interchange methods for the sake of demanded size of data packet, frequency of connections, meaning of the data, security and safety of the transmission as well as many others. One of the intensively spreading wireless networks is LoRaWAN. Because of its low energy consumption, long distance range, and high flexibility, it seems to be very effective solution to apply in the field of road traffic. The article presented the base features of LoRaWAN as well as the conception of virtual local traffic system based on the data yield from the board systems of cars. Accessed from OBD information about f. e.g. temporary cars speed or accelerations associated with their current position can be significant factor in creating the real image of the traffic situation.

Schlüsselwörter

  • automotive
  • communication networks
  • car parameter monitoring
  • CAN
  • modular system
Uneingeschränkter Zugang

Simulation of Rime Icing and Its Effects on Aerodynamic Characteristics of an Airfoil

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 437 - 443

Zusammenfassung

Abstract

A mathematical model for simulation of icing dedicated to simulation of ice accretion and its effects on aircraft aerodynamic characteristics in conditions of rime icing is presented. Pure rime icing occurs at lower temperatures than glaze icing and results in higher roughness of the surface of deposited ice. The model accounts for increased surface roughness, in terms of equivalent sand grain roughness, caused by deposited rime ice, which influences generation and dispersion of heat in the boundary layer. Increase of surface roughness is determined by analytical models created upon experimental data obtained in icing wind tunnels. Increased generation of heat is a result of increased tangential stress on the surface and is quantified in the temperature recovery factor determined numerically by a CFD solver. Effects of surface roughness on the intensity of forced convection are quantified by application of Colburn analogy between heat and momentum transfer in the boundary layer, which allows assessment of heat transfer coefficient for known friction coefficient, determined by CFD. The computational method includes determination of the surface distribution of mass of captured water in icing conditions. The model of freezing of captured water accounts for generation of heat due to latent heat of captured water droplets, temperature recovery in boundary layer and kinetic energy of captured droplets. The sinks of heat include forced convection, heating of super cooled droplets, conduction of heat through the ice layer and sublimation. The mathematical model is implemented as user-defined function module in ANSYS Fluent solver. The results include effects of deposited ice, including increased surface roughness on aerodynamic characteristics of an airfoil.

Schlüsselwörter

  • computational fluid dynamics
  • aerodynamics
  • two-phase flow
  • simulations of ice accretion
  • heat exchange
  • aircraft engineering
  • transport
  • vehicles
Uneingeschränkter Zugang

Level of Manipulation of Digital Recording Devices in Light of Introducing ERRU System in European Countries

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 445 - 452

Zusammenfassung

Abstract

The tachograph is the oldest recording device, which belongs to the Group of ORD (On Board Recording Devices). It was introduced in the USA in 1939. Digital tachograph, the new advanced type of recording device in road transport, was introduced by Council Regulation No 2135/98 of 24 September 1998 with the beginning of May 2006, in the area of the European Union. “In contrast to its analogue predecessors the digital tachograph was introduced to facilitate the control of rest and driving times and to prevent manipulation attempt. In order to prevent abuse, it has been made the system of cryptologic keys and certificates stored in cards and devices, allowing creating explicit laws of users and authentic data recorded in, cards and devices. The Hasler Event Recorder was introduced in the 1920s. Regrettably, the construction of analogue tachograph, an original type of tachograph is used in road transport, encouraged to numerous frauds and counterfeits of social rules for drivers. Secure digital tachograph system is indisputably a means having the great influence on road safety, enforcement of the social conditions for drivers in road transport as well as supporting the fair competition between road transport undertakings. In order to better monitor the compliance of road transport with the rules in force, inter alia the provisions on usage the digital tachographs, the European Union regulation introduces the European Registers of Road Transport Undertakings (ERRU), a system that allows a better exchange of information between Member States.

Schlüsselwörter

  • digital recording device
  • procedure
  • safety
  • system
  • European Registers of Road Transport Undertakings
Uneingeschränkter Zugang

Influence of Internal Space Frame in Body Shell on Change of its Response as a Result of Impulse Forcing

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 453 - 458

Zusammenfassung

Abstract

In order to increase the stiffness anybody chassis in Wheeled Armoured Vehicle on impact of the shock wave, the space frame part in body shell was conducted. The aim of this action is to reduce deformation and damage as a result of the detonation of the mine or an Improvised Explosive Device (IED) under the vehicle. To verify the conducted modernization, numerical calculations of the system response to a blast wave effect were carried out. The mass of the detonated explosive was increased from 6 to 20 kg of TNT. An explosive material was detonated centrally under the vehicle front part according to NATO requirements [1, 2]. The results of the calculations allowed for a deformation assessment of the floor plate and its displacement before and after modernization. A model and numerical calculations were performed using the following software: CATIA, HyperMesh, LS-PrePost, LS-Dyna. CONWEP approach was used to describe an influence of a pressure wave on the structure.

Schlüsselwörter

  • blast wave
  • Light Armoured Vehicle (LAV)
  • CONWEP
  • chassis
  • space frame
  • body shell
Uneingeschränkter Zugang

Multi-Parametric and Multi-Objective Thermodynamic Optimization of a Spark-Ignition Range Extender ICE

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 459 - 466

Zusammenfassung

Abstract

The current legislation pushes for the increasing level of vehicle powertrain electrification. A series hybrid electric vehicle powertrain with a small Range Extender (REx) unit – comprised of an internal combustion engine and an electric generator – has the technical potential to overcome the main limitations of a pure battery electric vehicle: driving range, heating, and air-conditioning demands. A typical REx ICE operates only in one or few steady-states operating points, leading to different initial priorities for its design. These design priorities, compared to the conventional ICE, are mainly NVH, package, weight, and overall concept functional simplicity – hence the cost-effectiveness. The design approach of the OEMs is usually rather conservative: parting from an already-existing ICE or components and adapting it for the REx application. The fuel efficiency potential of a one-point operation of the REx ICE is therefore not fully exploited. This article presents a multi-parametric and multi-objective optimization study of a REx ICE. The studied ICE concept uses a well-known and proven technology with a favourable production and development costs: it is a two-cylinder, natural aspirated, port injected, four-stroke SI engine. The goal of our study is to find its thermodynamic optimum and fuel efficiency potential for different feasible brake power outputs. Our optimization tool-chain combines a parametric GT-Suite ICE simulation model and modeFRONTIER optimization software with various optimization strategies, such as genetic algorithms, gradient based methods or various hybrid methods. The optimization results show a great fuel efficiency improvement potential by applying this multi-parametric and multi-objective method, converging to interesting short-stroke designs with Miller valve timings.

Schlüsselwörter

  • Range Extender
  • hybrid electric vehicle
  • battery electric vehicle
  • internal combustion engine
  • spark-ignition
  • thermodynamic optimization
  • genetic algorithm
Uneingeschränkter Zugang

Statistical Analysis of Ground-Related Incidents at Airports

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 467 - 472

Zusammenfassung

Abstract

In recent years, the aviation sector has been developing dynamically. The constant increase in the number of passengers contributes to an escalation in the number of air operations. This trend is mainly due to the increased traffic not only in airspace but also within airports. The large concentration of aircraft at the largest airports makes ground-flying phases such as taxiing or take-off becoming a challenge for pilots, ground services, and air traffic controllers. An intensive operation of many objects on the airport's manoeuvring areas can lead to collisions between them. Global air traffic is growing constantly, with record numbers of air operations and passengers carried. The probability of a collision increases, which leads not only to the cancellation of the flight but also to the significant costs of the aircrafts repair. The statistical analysis allows to highlight the problems related to the issue of ground collisions at airports and can also confirm the thesis concerning the growth and density of air traffic.

Schlüsselwörter

  • air transport
  • statistical analysis
  • airports incidents
Uneingeschränkter Zugang

Effects of Renewable Energy Sources on Air-Fuel Ratio

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 473 - 477

Zusammenfassung

Abstract

Environmental emission of road transport is a key problem. Periodic environmental test are designed to ensure minimum emission. Periodic checks are based on measurements. In this emission measurements fuel type plays an important role. The Brettschneider equation is a method used to compare the idealized and actual air fuel ratio. Brettschneider established a method to calculate ratio of oxygen to fuel by comparing the ratio of oxygen molecules to carbon and hydrogen molecules in the exhaust. In this article, authors have investigated blended ethanol effect on idealized and actual air fuel ratio based on Brettschneider equation. The main result of the article that blended ethanol has insignificant effect on air-fuel ratio. The article presents inter alia difference in stoichiometric air fuel ratios in case of different fuels, changes in λ due to blending ethanol and comparison of influence of emissions of different types of transport. In the article authors focus particularly on periodic checks and gasoline driven cars. The main research question was if ethanol blends have effect on idealized and actual air fuel ratio based on Brettschneider equation.

Schlüsselwörter

  • air-fuel ratio
  • lambda
  • gasoline
  • ethanol
  • combustion engines
  • air pollution
  • environmental protection
Uneingeschränkter Zugang

Wind Power Plants – Types, Design and Operation Principles

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 479 - 487

Zusammenfassung

Abstract

Many countries worldwide support green energy production on large scale mostly by solar or wind energy subsidizing manufacture and operation of such systems. During the last two decades, there has been significant increase in wind energy production globally. Statistics show continuously growing investments in the development and installation of wind turbines and farms. Currently, wind energy is the second most important source of renewable energy after water energy. By 2016 global cumulative installed wind capacity surpassed 432 k MW [GWEC]. In last several years, most dynamic growth in wind power generation investments was recorded in Asia. Europe, in comparison, has less impressive but steady growth in wind power plants through the years. In this article, authors present global demand on energy in comparison to efficiency of wind power plants in relation to the local and global location as well as to the scale of installed system. Authors also present statistical data concerning wind power plants development. General classification, using number of criteria (ex. power output, construction size, rotor axis orientation and other) of wind to electric power converting devices is presented. Various types of devices, which authors describe in this article, can perform conversion of wind blow energy to the electric energy using different yet similar methods.

Schlüsselwörter

  • wind energy
  • wind power plants
  • energy conversion
  • renewable energy
Uneingeschränkter Zugang

Area of the Unstable Solution of Rolling Equation – Jumps of the Oscillations Amplitude

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 489 - 496

Zusammenfassung

Abstract

The most interesting motion of the ship is rolling. This is because the rolling amplitudes are much bigger than amplitudes of other degrees of freedom and under resonance conditions, which can exceed 40º. In such a case, when the maximum of the righting arm curve is placed at relatively small angles, the roll equation reveals a strongly nonlinear character and bistability areas as well as an area of unstable solutions of the roll equation occurs. Together with the appearance of the above-mentioned areas, amplitude jumps are possible. In the study, the case of strongly nonlinear rolling is analysed. For the purpose of numerical simulations, the 1DOF mathematical model of rolling with damping dependent on amplitude and frequency is used. The article presents the roll spectrum including the bistability areas and the area of unstable solutions for one loading condition of the offshore support vessel. It is demonstrated that for strongly nonlinear rolling, rolling with two different amplitudes for the same value of excitation is possible. It is also shown that transitions (jumps) between these amplitudes are possible too. A few scenarios of jumps of the rolling amplitude within the region of unstable solutions of the rolling equation are presented. The presented rolling scenarios show that under some circumstances rolling can be observed as chaotic.

Schlüsselwörter

  • ship rolling
  • nonlinear oscillations
  • nonlinear resonance
  • bistability
  • bifurcations
  • amplitude jumps
Uneingeschränkter Zugang

The Method of Lubrication for Vegetable Grease

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 497 - 504

Zusammenfassung

Abstract

This article covers new aspects and a method of hydrodynamic lubrication of various friction pair using vegetable non-Newtonian greases. Biological greases and oils are applied in slide journal bearing lubrication occurring in farm and consumption machines working in pollution sensitive areas. Further applications can be found in humanoid robots joint lubrication as well as lubricants in various friction pairs, for example in gear and other friction nods. The following belong to new vegetable greases: Accu-Lube LB10000 as medium to heavy duty machining oil, Accu-Lube LB 4000 – light to medium duty machining oil. Bio-vegetable greases have very important characteristic features and they offer the following benefits: prevention of corrosion protection-preventing premature failure, maximum penetration-ensuring protection at the cable core, extreme wash-off resistance that guarantees protection in wet conditions. Furthermore, the presented vegetable greases have biodegradability properties; hence, this fact has important meaning in temporary environmental problems. The aim of this article is to present a new general analytical and numerical solution of the hydrodynamic lubrication problem, to determine the influence of the vegetable grease and its biological additions on the temperature distribution in the internal surfaces of the slide bearing sleeve and pressure distribution in the bearing gap or on the cooperating surfaces of the friction pair. The research methods and materials used in this article include the following: the Mathcad 15 Professional Program and new semi-analytical methods applied in connection with the theory of hydrodynamic lubrication extended to the curvilinear orthogonal surface and coordinates. Particular solutions are introduced to the cylindrical coordinates. The obtained results of the lubrication of the movable sleeve surface include a new model of the hydrodynamic lubrication theory. As a consequence of the new method of calculation indicated the intervals are provided of the increases and decreases of the dynamic viscosity of greases and the intervals of the hydrodynamic pressure increments and decrements versus of the pH (power hydrogen ion concentration) of greases and wettability of vegetable greases into cooperating surfaces.

Schlüsselwörter

  • biological greases
  • hydrodynamic lubrication
  • biodegradability aspects
  • corrosion protection
  • new model of calculations
Uneingeschränkter Zugang

Chosen Development Problems of Wheeled Armoured Transporters

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 505 - 510

Zusammenfassung

Abstract

Modern wheeled armoured vehicles are constructed as multipurpose. Universal construction of vehicle is achieved in two separate ways: as specialized versions of vase model or by using exchangeable mission-modules. Realization of various tasks requires different equipment; ensure adequate level of protection and firepower. Increase of protection level, implementation of weapon systems, characterized by high firepower despite technological advancement in this field affect vehicles weight increase and therefore, it also affects requirements for other vehicle systems. Ensuring high mobility requires use of high power, turbocharged diesel engines, hydro mechanical transmission, hydro pneumatics suspension, possibility of clearance adjustment, use of central wheel pumping system enabling tire pressure change according to the surface on witch vehicle runs. This study gathers and compares characteristics of selected wheeled armoured personnel carriers and determines possible directions of development for future wheeled vehicles.

Schlüsselwörter

  • wheeled armoured transporter
  • construction development
  • tendencies
Uneingeschränkter Zugang

Properties of Corrosive Coated Coatings Multi-Groove Hardfacing on Stainless Steel

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 511 - 516

Zusammenfassung

Abstract

Using the pad welding technique it is possible to regenerate machine parts or improve surface properties such as abrasion, corrosion and aging resistance. To ensure optimum processing conditions and economic efforts should be made, while providing a high deposition efficiency for the small amount of metal in the pad weld substrate. The pad welding process for the test subject should be carried out by preheating to evaporate the moisture and reduce the porosity of the weld. This treatment is required depending on the carbon equivalent. The article presents the results of corrosion tests of multi-groove pads made with the MIG method on a steel substrate. The samples were made of C45E steel. The additional material was a wire made of stainless steel with the factory name CASTOMAG 4554S. The results of previously performed tests allowed determining the optimal process parameters at which we obtain the smallest share of the base material in the padding. Steel samples were prepared and preheated to 300ºC. The hardfacing process was carried out with constant parameters, i.e. current intensity, arc voltage, surfacing speed). Two protective gases were used to apply the additional material: CO2 and argon. The samples were subjected to corrosion tests in two environments (3.5% sodium chloride solution and 0.001 sulfuric acid solution). The assessment of corrosive properties was made on the basis of constant current measurements (potentiodynamic method). The influence of shielding gas on corrosion properties was demonstrated based on the tests.

Schlüsselwörter

  • corrosion
  • hardfacing
  • MIG
  • Taguchi method
  • seawater
Uneingeschränkter Zugang

Investigation of Knock Suppression Characteristics in a Boosted Methane – Gasoline Blended Fuelled SI Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 517 - 525

Zusammenfassung

Abstract

Natural gas has a higher knock suppression effect than gasoline which makes it possible to operate at higher compression ratio and higher loads resulting in increased thermal efficiency in a spark ignition engine However, using port fuel injected natural gas instead of gasoline reduces the volumetric efficiency from the standpoints of the charge displacement of the gaseous fuel and the charge cooling that occurs from liquid fuels. This article investigates the combustion and engine performance characteristics by utilizing experimental and simulation methods varying the natural gas-gasoline blending ratio at constant engine speed, load, and knock level. The experimental tests were conducted on a single cylinder prototype spark ignited engine equipped with two fuel systems: (i) a Direct Injection system for gasoline and (ii) a Port Fuel Injection (PFI) system for compressed natural gas. For the fuels, gasoline with 10% ethanol by volume (commercially known as E10) with a research octane number of 91.7 is used for gasoline via the DI system, while methane is injected through PFI system. The knock suppression tests were conducted at 1500 rpm, 12 bar net indicated mean effective pressure wherein the engine was boosted using compressed air. At 60% of blending methane with E10 gasoline, the results show high knock suppression. The net indicated specific fuel consumption is 7% lower, but the volumetric efficiency is 7% lower compared to E10 gasoline only condition. A knock prediction model was calibrated in the 1-D simulation software GT-Power by Gamma Technologies. The calibration was conducted by correlating the simulated engine knock onset with the experimental results. The simulation results show its capability to predict knock onset at various fuel blending ratios.

Schlüsselwörter

  • knock
  • methane
  • gasoline
  • E10
  • blend fuel
  • knock onset prediction
  • simulation
Uneingeschränkter Zugang

Testing of an Engine fuelled with Rapeseed Oil

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 527 - 532

Zusammenfassung

Abstract

Rapeseed oil in a few applications can be used as an engine fuel. Although it has worse properties than its methyl esters, it can be considered as an alternative fuel in engines adapted to its use. The article describes some problems resulting from the use of pure rapeseed oil as a fuel for compression ignition internal combustion engines. Differences between basic physical and chemical properties between diesel oil and rapeseed oil will be discussed and their impact on the theoretical engine performance and emission of pollutants from the exhaust system, with a focus on viscosity of rapeseed oil and the impact of this parameter on the fuel injection process. The basic changes in the engine design to be able to run on the rapeseed oil are discussed. The results of author’s own tests of the engine adapted to operate on the rapeseed oil and its blends with diesel oil carried out on the engine dynamometer test bench are presented. The theoretical assumptions presented in the Introduction were tested experimentally in the dynamometric test. Combination of higher density of rapeseed oil and its smaller stoichiometric value caused by the presence of oxygen and a smaller share of hydrogen in the fuel, means that a larger mass of fuel can be injected into the charge compressed into the cylinder. Thanks to this, the engine powered by rapeseed oil and diesel oil can reach similar powers.

Schlüsselwörter

  • transport
  • road transport
  • combustion engines
  • air pollution
  • environmental protection
  • emissions testing
Uneingeschränkter Zugang

Emissions from Engines Fuelled with Biofuels

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 533 - 539

Zusammenfassung

Abstract

In recent years, the interest in the use of renewable fuels in transport has increased. This is due to the European Union’s policy to reduce greenhouse gas emissions. These fuels, in addition to the effect of reducing carbon dioxide and the other greenhouse gases, may increase the emissions of other exhaust components. The article describes the problems of pollutants emissions from the engine exhaust system, related to the use of biofuels in combustion engines or their additives in conventional fuels. The influence of the chemical composition of selected biofuels on the emissions properties of vehicles and their engines will be discussed. The tests results of engines fuelled with selected biofuels, carried out by the authors of the article, will be presented. These tests will be carried out on chassis dynamometer and engine test bench, in standard research tests used in measurements of pollutants emissions like NEDC, ESC, ETC, etc. Furthermore, selected operational parameters of vehicles and engines will be compared with biofuels and conventional fuels.

Schlüsselwörter

  • biofuels
  • emissions
  • road transport
  • combustion engines
  • environmental protection
Uneingeschränkter Zugang

The Use of Parametric Structure Modelling in the Design Process

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 541 - 548

Zusammenfassung

Abstract

Automation of processes related to design and manufacturing is one of the essential goals of most manufacturing companies. The use of modern computer-aided design systems CAD allows partial automation of such processes. The parametric model can be built in some CAD systems. In the parametric model, selected dimensions are treated as control parameters. By changing the values of these parameters, we can control the remaining geometrical dimensions of the model. These dimensions can be associated with linear control parameters using mathematical relationships. Parameterization allows you to associate a geometric model with a mathematical model and allows you to automatically make changes to all elements associated with the currently modified parameter. When working on a non-parameterized model, the changes in the modelled object must be applied separately for each part and subassembly of which it is composed. In a parametric model, changing one parameter entails changes in other parameters dependent on it. Parameterization of the model allows its use for further modification of the designed structure related to customer requirements, even for that very complex, as well as accelerating the design process itself. The article presents a three-dimensional geometric model of a boat davit created with the use of the Siemens NX 9.0 software. In the work, the geometry of the crane model was parameterized for the assumed values of its height and reach. As a result of parametric modelling, the values of the individual geometric dimensions of the device’s structure elements and their mass were obtained. It was justified that thanks to the use of parameterized models, the time of design and construction processes can be significantly reduced, which makes the process more efficient.

Schlüsselwörter

  • parameterization
  • control parameters
  • modelling
  • davit
  • automation
Uneingeschränkter Zugang

Aircraft Docking Guidance System to the Gate Using Fuzzy Logic

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 549 - 556

Zusammenfassung

Abstract

The article presents the concept of automated final process of aircraft taxiing to the gate at the terminal. On the basis of an analysis of the possibilities of aircraft taxiing in civil airports, the authors attempted at optimizing this process. The main objective of the project is to reduce the taxiing time, consequently reducing fuel consumption as well as the rotation time. As a result of the work, the authors designed a controller based on fuzzy logic, which, depending on the initial parameters, calculates the set values for the execution system of aircraft control in the horizontal plane and for the taxi speed. The controller receives two input signals, which determine two output signals. The designed controller allows comprehensive and fully automated aircraft steering. The project relies on data with regard to the apron class D, suited to handle aircraft with a wingspan of up to 52 m and the characteristics of a Boeing 767-200 in speed taxiing and the maximum turn of the nose gear. The measurements of the apron have been adopted in accordance with international regulations in the ICAO DOC 9157 “Aerodrome Design Manual”. The maximum deviation of the nose gear from the centre line was assumed 2.5 m in each direction and a safe distance behind the immobile aircraft equal to 25 m. The length of the Boeing aircraft 767-200 is below 48 m, therefore the input boundary parameters are equal to +/− 2.5 m from the centre line and 80 m from the designated aircraft stand (nose gear). The article presents the project of the controller and its optimization. The authors simulated the controller operation in the package MATLAB “Simulink”. The article ends with data analysis and final conclusions.

Schlüsselwörter

  • fuzzy logic
  • fuzzy expert system
  • aircraft taxiing
  • aircraft steering
68 Artikel
Uneingeschränkter Zugang

Effect of the Type of Aging after Supersaturating on Hardness and AW-7020 Stop Structure

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 9 - 16

Zusammenfassung

Abstract

Aluminum alloy AW-7020 is characterized by high fatigue strength. It is used primarily in welded constructions, which should be characterized by high strength and resistance to cyclically variable operational loads. They have found wide application in light welded ship constructions, bridge-carrying elements, cranes, hoists, vehicles, roof beams in roof constructions, and security barriers. The paper attempts to determine the influence of selected types of applied heat treatment on the structure and hardness of the AW-7020 alloy used in the shipbuilding industry. Heat treatment processes have been described in the aspect of improving the mechanical and strength properties of the tested alloy and its impact on ductility. Several supersaturation and aging sequences were used in the course of the study. The results of hardness tests of aluminum alloy after its earlier supersaturation and aging (natural and artificial) have been presented. Photographs of internal structures in individual sequences were taken. The obtained hardness measurement results and analysis of structures in individual states were compared with the delivery condition. To illustrate selected heat treatment processes, transient tests were also performed to accurately verify the effect of aging after saturation on hardness and changes occurring in the material structures. The results of the material tests showed that the type of heat treatment after saturation is of significant importance for the hardness and structures of the AW-7020 alloy. As a result of the research, it was proved that the tested alloy obtained in the artificial aging process more favourable strength properties, in a shorter period, compared to the use of the natural aging process.

Schlüsselwörter

  • AW 7020 alloy
  • natural aging
  • artificial aging
  • saturation
  • hardness
  • ductility
  • internal structure
Uneingeschränkter Zugang

Study of the Pilot’s Attention in the Cabin During the Flight

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 17 - 24

Zusammenfassung

Abstract

The pilot, while performing certain tasks or being in the battlefield environment works in a time lag. He is forced to properly interpret the information and quickly and correctly take action. Therefore, the instruments in the cabin should be arranged in such a way that they are legible and the operator have always-easy access to them. Due to the dynamics of the aircraft and the time needed to process the information by the pilot, a reaction delay occurs, resulting in the plane flying in an uncontrolled manner even up to several hundred meters. This article discusses the VFR and IFR flight characteristics, the pilot’s attention during flight, cabin ergonomics, and the placement of on-board instruments having a significant impact on the safety of the task performed in the air. In addition, tests have been carried out to determine exactly what the pilot’s eye is aimed at while completing the aerial task. Six basic devices were identified: altimeter, artificial horizon, speedometer, turn indicator with transverse gauge, variometer and heading indicator. They also started to think about how to position them in relation to each other in order to achieve the best results in terms of ergonomics, which include, minimizing time of reading individual parameters, grouping devices with parameters closely related to each other, reducing to a minimum the value of errors during reading and the smallest possible pilot’s effort.

Schlüsselwörter

  • transport
  • battlefield environment
  • pilot reaction delay
  • device parameters
  • parameters reading time
Uneingeschränkter Zugang

Aerodynamics of Articulated Multilink Trucks

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 25 - 32

Zusammenfassung

Abstract

Development of new generations of supersize heavy-duty highway trucks for cargoes transportation on long and super long distances between Europe, Asia and Far East is actual now. New trucks shall reduce amount of transport on roads and quantity of drivers, involved in the transportation, will raise economic efficiency and safety of transportations and reduce fuel consumption, CO2, and harmful emissions. Multilink trucks (number of trailed links is three and more and the total truck length is above 40 m) are to achieve designated purposes and thus are under the scope in the article. The advantages of multilink trucks are formed mainly by reducing the cost of power to overcome the aerodynamic resistance of each co-trailer unit in comparison with the head element. However, the airflow in every trailer-trailer gap has been not studied for articulated vehicles such as multilink highway trucks. This zone of the truck is characterized by a rather large length and height, and the condition of the air mass is influenced by airflow from the roof, side panels and area under the bottom of a truck links. A study of this task will help us to analyse aerodynamic losses mechanics in the trailer-trailer gap and to come to new effective and substantiated decision allowing power loss and thus fuel consumption reduction. The study lists the general calculation method evaluating the aerodynamic characteristics of the multilink truck on the base of numerical simulation of fluid dynamics using Flow Vision software. During calculation, there were determined speed distribution and power lines along the truck, the distribution of pressure on the truck surface, power and full drag coefficient. The results obtained allowed numerically evaluate the effect of the distance between the links on fuel consumption for multilink trucks and define the desired changes in their design.

Schlüsselwörter

  • truck
  • aerodynamic resistance
  • articulated truck
  • trailer-trailer gap
  • modelling
Uneingeschränkter Zugang

Torgas Condensate Combustion in the SI Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 33 - 38

Zusammenfassung

Abstract

The article presents results from IC engine tests on combustion of alcohol fuel with the addition of torgas condensate. Torgas is a by-product created from the torrefaction of Sida hermaphrodita. It was obtained from torrefaction carried out at a temperature of 400°C. Torgas was condensed in a tubular cooler. The basic fuel was butanol. This fuel was chosen, because regular hydrocarbon based fuels got delaminated while blended with torgas condensate. The condensate dissolves in alcohol therefore the choice was justified. In the mixture, the volume ratio of alcohol to condensate was 4:1. The combustion was carried out in a spark-ignition, single-cylinder engine with a cubic capacity of 650 cm3. The engine was able to vary its compression ratio. The engine worked at full load at maximum open throttle. The engine body was heated to a temperature of 95°C and this temperature was maintained throughout the testing period. The engine was running at 850 rpm. The first stage of the experiment included determination of the optimal ignition angle for butanol as a reference fuel and for a mixture of butanol and torgas condensate. The optimal spark angle was estimated based on the maximum indicated work. Three compression ratios, i.e.: CR=8.8, 10 and 11.2 were used. All tests were performed for a stoichiometric air fuel ratio. The obtained in-cylinder pressure diagrams for the reference fuel and the fuel with the addition of condensate were compared with each other. The rate of pressure increase inside the cylinder was calculated. For all tests, the following exhaust components were measured: CO2, CO and HC.

Schlüsselwörter

  • SI engine
  • butanol
  • bio-oil
  • torgas condensate
  • exhaust emission
  • torrefaction
Uneingeschränkter Zugang

Optimisation of Aircraft Position in the Formation Flight for the Drag Reduction

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 39 - 50

Zusammenfassung

Abstract

This article presents optimisation of necessary flight thrust in a V-shaped flight formation of small-unmanned plane “Sikorka”. At the beginning is showed analyse of birds behaviour. Their formation flying was the cause of attention in order to minimalize fuel consumption. Afterwards there are overlooked scientific articles about the formation flying subject contain pure physic analyses, and articles about researches which was made in order to explain economic beneficial for airlines. Thus, the article presents mathematical model, which was optimised for three different starting position of a longitudinal axis. After optimisation there are presented results of the wingman position in regard of the leader. Influence of the calculation results on the formation flying was analysed, allowing for some conclusions about the future of the UAV’s flights. The given process is aimed to achieve the best (optimal) solution from the point of view of the specific criterion. The following most important terms can be distinguished within the optimization process: decisive variables – parameters determining the basic project assumptions. The basic design variables and design constrains are described.

Schlüsselwörter

  • UAV
  • formation flying
  • optimisation
  • dynamic of flight
  • aerodynamic
Uneingeschränkter Zugang

Numerical Analysis of Heat Conduction Influence on SCR Aftertreatment Systems Efficiency

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 51 - 58

Zusammenfassung

Abstract

Selective Catalytic Reduction (SCR) is well known method for reducing NOx emission in diesel engine exhaust gas. Urea-water solution (UWS) injected into hot stream decomposes due to thermolysis into ammonia and isocyanic acid which hydrolyses further into more ammonia and carbon dioxide. Resultant ammonia is the NOx reductor, producing water vapour and carbon dioxide from the reduction reaction. To provide sufficient NOx reduction efficiency, UWS needs to be properly atomized and mixed with exhaust gas. However, due to more and more restrictive emissions regulations provided by European Union and Close Coupled trend of aftertreatment systems in vehicles the design process is very complex and demanding. Computational Fluid Dynamics (CFD) simulations are integral part of product development, allowing save time and reduce costs of preparing prototypes for further tests. However, it is necessary to understand all the processes and problems connected with NOx reduction in SCR system. Strong turbulent flow of hot stream gas, urea-water solution spray injection, droplets interaction with wall, wallfilm generation are included. The objective of this work is to investigate the impact of heat transfer modelling inside mixing elements of SCR system on urea mixing uniformity and wallfilm deposit on the walls of the system. Simplified and more complex approach is compared with no heat transfer cases. All the simulations were conducted using AVL FIRETM software. Results showed that wall heat transfer might have an impact on mixing efficiency and wallfilm formulation. It is necessary to take into account the effect of mixing elements heat conduction in CFD simulations during the aftertreatment design process.

Schlüsselwörter

  • SCR
  • simulation
  • heat conduction
  • aftertreatment
Uneingeschränkter Zugang

Light Absorption Properties of ‘Petrobaltic’ Oil-in-Water Emulsion Present in Seawater

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 59 - 64

Zusammenfassung

Abstract

In the article, the characteristic of crude oil ‘Petrobaltic’ potentially present in the Baltic Sea water masses is considered in relation to the protection of marine environment. The main spectroscopic method to characterize various oils (crudes and refinery products like fuels and lubricating oils) is fluorescence. However, the absorbance measurements of oils are necessary due to the partial overlapping the spectra of natural seawater components and oil substances. Therefore, properties of crude oil are considered to expand the basis of spectroscopic properties of oils – typical marine organic pollutants – based on absorption measurements. Oils potentially found in the marine environment are, in addition to surface forms, also in-depth ones as oil-in-water emulsion. Therefore, in the article crude oil as oil-in-water emulsion form is considered. As a solvent demineralised water with salinity, corresponding to Baltic Sea salinity was used. Several concentrations of dispersed crude oil were prepared. The absorbance spectra in the UV and visual range of the light in the range from 240 to 600 nm, for each prepared samples are discussed. Based on the Lambert-Beer law for each wavelength of excitation, in the range 240-600 nm, the specific parameter absorption coefficient was determined. Obtained results indicate the rapid decreasing of the absorbance for this kind of oil in the wavelength range from 240 nm to 420 nm. However, in the shape of absorbance spectra is observed the characteristic wide and flat peak located at 260 nm for excitation wavelength, which could be a specific point for this kind of oil.

Schlüsselwörter

  • crude oil
  • absorbance
  • absorption spectra of dispersed oil
  • absorption coefficient
  • oil-in-water emulsion
Uneingeschränkter Zugang

Analysis of the Procedure of Evaluation of the Technical Condition of a High-Pressure Common Rail Fuel Pump Using a Test Bed

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 65 - 70

Zusammenfassung

Abstract

Piston displacement pumps use in common rail fuel injection systems generates very high pressure, reaching even 300 MPa. Maintaining such a high pressure is possible thanks to very precise machining resulting in as little clearance between the piston-cylinder assemblies. Due to very high forces operating in the systems and relatively unfavourable lubrication conditions resulting from using fuel as lubricants, the pumps are subject to wear and consequently lose their operating parameters. The high cost of production of the pumps, resulting from their technological advancement, forced their manufacturers to introduce technologies for diagnosing and regenerating them. The diagnostics consists in removing the pump from the engine and having it verified using a test bed. The first stage consists of evaluating the pump’s flow at null pressure; follow by evaluation of its maximal delivery for the pressure of 100 MPa. The obtained values are compared to the values achieved by a new pump. The effect of negative evaluation on a test bed is the disassembly of the pump, verification of the condition of its parts and replacement of the damaged elements. The authors examined new and used pumps on a tested, aiming to determine the characteristics of delivery of a pump for various pressures. The objective of the research was to identify the actual points in the pump’s operation at which the delivery drops the most due to the wear. The highest difference in delivery was found to exist for the maximal compression pressure. The obtained results were analysed and the possibility of changing the pump diagnostics procedure with the use of a test bed was determined.

Schlüsselwörter

  • common rail
  • test bench
  • diagnostic
Uneingeschränkter Zugang

Evaluation of the Possibility of Occurrence of Selected Damage to a Car Engine Turbocharger Using the Event Tree Analysis (ETA)

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 71 - 76

Zusammenfassung

Abstract

The subject of the article is the identification of factors behind the incorrect operation of a car turbocharger that, in longer perspective, lead to the damage of the device. Due to the operating principle and design features, the device works with many engine systems – intake, exhaust, lubrication systems and also, increasingly more often, with the cooling system. A multitude of relations, complexity, and working conditions are reasons due to which the device is sensitive to disturbances of quality parameters of the working media (e.g. oil). In the article based on the selected causes of damage of turbochargers, we focused on the following initiating event, concerning the bearings lubrication system, which is clogged oil strainer. The authors aims at performing an analysis allowing to increase the detectability of emerging malfunctions that lead to deterioration of operating conditions of the device. For this task tool such as ETA (Event Tree Analysis) was used. It is a tool for assessing system and process safety. It facilitates detecting potential risks, as well as relations existing between actions or events. This method explores the path from the initiating event to the outcome (most often representing the immobilization of the tested object), with particular emphasis on intermediate stages affecting the technical condition of the object. Unlike the FTA analyses, which have a deductive nature, the ETA analysis is inductive. The analysis of the obtained results, supported with validation by means of ETA, allowed proving that, given the current state of knowledge and advancements in technology, it is possible to apply additional sensors for monitoring the operation of a turbocharger. The proposed modifications were considered minor design changes that significantly increase the reliability of the device.

Schlüsselwörter

  • turbocharger
  • combustion engines
  • Event Tree Analysis
  • ETA
Uneingeschränkter Zugang

Volatile Organic Compounds Removal From Vehicle Interior Based on Photocatalytic Solution

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 77 - 84

Zusammenfassung

Abstract

The article presents results of research work which aim was development of solution for volatile organic compounds (VOCs) removal from vehicle indoor air. VOCs, especially benzene, toluene, and xylene (BTX), are air pollutants responsible for many civilizational diseases because of its carcinogenic and mutagenic properties. Concentration of those substances can be even few times higher in micro atmosphere of vehicle cabin than in other indoor atmospheres [1]. The aim of the scientific cooperation between Dr. Schneider Automotive Polska and the Wroclaw University of Science and Technology (WUST) is research on innovative (international range), product development – photocatalytic reactor characterized by Volatile Organic Compounds, especially BTX removal properties. The BTX reduction effectiveness, caused by photocatalytic reactor application in vehicle ventilation system, was subjected to in-depth analysis. The results showed difference on not only maximal benzene, toluene, and xylene reduction (separately) but also in the pattern of response surface. In some tested parameters, the hazardous compounds (as a BTX sum) were reduced for almost 70%. The photocatalytic reactor seems to be prospective solution for air quality improvement in any vehicle cabin.

Schlüsselwörter

  • automotive vehicle
  • benzene-toluene-xylene compounds
  • vehicle interior
  • indoor air
  • photocatalysis
Uneingeschränkter Zugang

Criteria of Similarity in Analysis of Main Dimensions and Propulsion Power of Ships at Preliminary Stage of Design

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 85 - 91

Zusammenfassung

Abstract

The article presents the methodology of calculation of principal parameters of ship’s hull dimensions, called „significant ships list”, at preliminary stage of design process. Knowledge collected in the database is related to new buildings classified according to type, displacement, or DWT, shipping class, maximum speed etc. Are analysed dimensional constraints due of Froude Number, ships dimensional coefficients block and weigh coefficient, relations of main dimensions such as L/B, B/T, L/H, B/H etc. [7]. Those parameters coming out from ship-owners requirements like type of ship, load capacity, type of cargo, shipping zone, speed and some more. Very helpful tool for such analysis is list of significant ships created for specified types of ships. Mentioned lists are very effective under conditions that cover broad-spectrum new buildings and data included are credible. Uncritical taking values included in significant ships list can lead to critical errors in selection of main dimensions of a ship or its propulsion powering. For that reasons, basing on analysis, as main criteria of similarity of ship’s hull were assumed mass coefficient, block coefficient and Froude Number [2]. That procedure has significant impact at proper estimation of propulsion power. Another reliable parameter of evaluation of power seems to be relation between power and load capacity Ne/D.

Schlüsselwörter

  • shipbuilding
  • calculation of hulls dimensions of ship and propulsive marine power
Uneingeschränkter Zugang

Effectiveness of the Active Pneumatic Suspension of the Operator’s Seat of the Mobile Machine in Depend of the Vibration Reduction Strategies

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 94 - 98

Zusammenfassung

Abstract

Low speeds of heavy mobile machines combined with large inertia result in the excitation of low frequency vibrations. Dissipation of vibration energy in the case of unsprung machines is performed only through tires, which slightly reduces the intensity of vibrations. Effective reduction of vibrations of mobile machines is possible only with active or semi-active methods. In unsprung mobile machines, on the way of propagation of vibrations between the source of vibrations and the protected object (machine operator), are vibroisolation systems located. These are most often controlled seat suspensions. In the case of the active suspensions, it is necessary to provide external energy, e.g. in the form of compressed air. The compressed air has the advantage that it is generally available in working machines as the working fluid and has its environmentally friendly properties (leaks do not contaminate the environment). This article is the result of the continuation of work on active methods of vibro-activity lowering in mobile machines, which resulted in, among others, elaboration of simulation model of the active operator’s seat suspension with controlled pneumatic actuator and its experimental identification. In particular, it was verifying the effectiveness of the adopted solution made the identification the friction model and thermodynamic phenomena in the controlled pneumatic cylinder. The aim of this work is parametric optimization of the suspension system and searching for the optimal control strategy. Experimental tests were carried out under conditions of harmonic excitations, coming from the electromechanical vibration exciter with controllable pitch and frequency. Data acquisition system and control circuit of the proportional directional control valve, supplying compressed air to the actuator were implemented using MATLAB-Simulink Real-Time software.

Schlüsselwörter

  • unsprung mobile machines
  • active vibration reduction
  • controlled suspension seats
  • pneumatic actuator
Uneingeschränkter Zugang

Test Flights in the Aircraft Operation Process

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 99 - 109

Zusammenfassung

Abstract

The article presents theoretical and practical aspects of aircraft reliability and safety of the performance of test flights in the operation process. The selected issues of operation of the means of transport in the aspect of the aircraft reliability, as well as the intensity of damage during the performance of test flights were presented. In short, the rules for operating the aircraft during test flights are described. A brief description of the causes of air crashes during test flights was presented, and the main hazards and risk occurring at the same time were shown. Subsequently, the authors’ methodology including a diagram for studying the aircraft features in terms of aerodynamic characteristics and performance and a model of the maintenance system of aircraft to perform the test flights, were demonstrated. The elements of the decision-making model, developed for this purpose, were briefly presented, showing the required and defined decision variables, constraints and an objective criterion function. The algorithm of the method was presented, and the examples of practical application and graphical data presentation in the DOSPIL application were indicated. The article was concluded with a short summary in which the main effects and directions of further work were presented.

Schlüsselwörter

  • aircraft test flights
  • organisation of test flights
  • testing of aircraft properties
Uneingeschränkter Zugang

Organization of the Highway Strip Repair Process

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 111 - 120

Zusammenfassung

Abstract

The article presents the possibilities of advance development of detailed organization-technical plans for the repair of Highway Strips, which will enable their effective use, particularly during combat operations – while maintaining the required time and technical standards at the same time. The main objectives of Highway Strips were presented; their role in securing military aviation activities and historical conditions for their creation. The concept of HS (Highway Strip) was defined along with the modern principles for their construction, modernization and renovation. Based on a selected example, the principles for evaluating the technical condition of their pavement and the repair possibility assessment were presented. At the same time, typical damage to HSs and factors affecting such damage were presented. Next, the methods and technologies for repairing various types of bituminous pavement damage repairs were discussed, with particular emphasis on the methods of repairing cracks, surface damage, deep damage and asphalt renovation. A schedule for the “Wielbark” highway strip was also developed, and the necessary calculations of the repair times, as well as the resources and resources for securing these operations were made. The article is concluded with a short summary and a proposal for further work, aimed at inhibiting the destructive processes of Highway Strips in Poland.

Schlüsselwörter

  • Highway strip
  • airfields
  • airstrips
  • runway repair processes
Uneingeschränkter Zugang

Implementation the GLONASS System in Aeronautical Application

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 121 - 128

Zusammenfassung

Abstract

The article determines the accuracy of positioning of the aircraft with the use of a satellite system GLONASS. In addition, the SPP (Single Point Positioning) absolute positioning method was utilized in research test in article. Research test was carried out in the new software APS (Aircraft Positioning Software), used for precise GPS/GLONASS satellite positioning in air navigation. The article describes the research method and presents mathematical formulas of the SPP positioning method. In the research test, the positioning accuracy of the Cessna 172 aircraft was obtained based on comparison of results between APS and RTKLIB software. The difference of Cessna 172 aircraft coordinates in the XYZ geocentric frame between the APS and RTKLIB solution is between −7 m to +6 m. The research material developed in the article comes from an aeronautical experiment carried out with the Cessna 172 aircraft for the EPDE military airport in Deblin.

Schlüsselwörter

  • Remote Maintenance System
  • air navigation
  • GLONASS
  • accuracy
  • Single Point Positioning method
Uneingeschränkter Zugang

Decomposition of Harmonic Wavelets of Torsional Vibrations as Basis for Evaluation of Combustion in Compression-Ignition Engines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 129 - 135

Zusammenfassung

Abstract

The aim of analysis presented in the article is results of measurements of torsional deflections of a crankshaft of three-cylinder internal combustion diesel engine. The wavelets of the run of torsional twists were processed by decomposition to harmonics using FFT. In order to exactly recognize all dynamic aspects of gas forces acting during working stroke, decomposition was done in two ways: first one relaying on records encompassing one working cycle (two revolutions), the second one based at separated periods encompassing angular an interval from TDC (Top Dead Centre) of one cylinder to TDC of subsequent in firing order. For three-cylinder engine, width of the interval is 240 degrees of crank angle. In order to obtain reliable results, torsional deflection signals acquisitions were recorded numerous times including changes of outer conditions (temperature, atmospheric pressure) and different values of the engine loads. The main goal of conducted experiments was looking for an answer of a question if exist any differences between frequency spectrums of harmonics of run of full cycle ( two revolutions) and the same cycle divided by three separate intervals. Analysis was conducted in order to state any possibility of diagnostic signals acquisition caused by abnormalities of combustion process. Results were presented in form of comparison of frequency spectra taken from full cycle and divided intervals.

Schlüsselwörter

  • diagnostics
  • diesel engine
  • torsional vibrations
  • signal processing
Uneingeschränkter Zugang

Physicochemical Properties of Fuel Compositions Obtained from Diesel Fuel and Different Kinds of Fatty Raw Material

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 137 - 143

Zusammenfassung

Abstract

Increased interest in development of alternative fuels used to power combustion engines is caused by excessive use of fuels obtained from mineral sources. Depletion of resources, political aspects as well as the negative impact on the environment are commonly discussed issues in relation to fossil fuels. On the other hand, biodegradability, lower toxic components emissions and interchangeability with mineral fuels are commonly described benefits related to biodiesel, interpreted as fatty acid methyl esters obtained from fatty raw material. Also the multiplicity of raw materials that can be used for production promotes popularization of the biodiesel. However the variety of raw materials can have significant impact on the number of physicochemical properties of alternative fuels due to the differences in molecular structures forming given type of raw material.

The article presents analysis of properties of different types of biodiesel and its mixtures with diesel according to the outlines presented in the quality standards for mineral and alternative fuels. Alternative fuels were produced in the laboratory setup from swine, poultry, rape and sunflower fatty raw material. Such parameters as: density, kinematic viscosity, flash point, acid value, oxidation stability, cold filter plugging point, sulphur content, water content and total contamination were examined, based on the results, the quality of the biofuels was evaluated. Study confirms that biofuels derived from plant origin fatty raw material present favorable results in the aspect water content, total contamination, acid value and cold flow properties, thus biofuels derived from animal origin raw fatty material presents lower density and sulphur content.

Schlüsselwörter

  • Biodiesel quality examination
  • biodiesel mixtures
  • animal fat biodiesel
  • vegetable oil biodiesel
  • transesterification
Uneingeschränkter Zugang

Influence of Biodiesel Origin on the Exhaust Gasses Concentration in Compression Ignition Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 145 - 152

Zusammenfassung

Abstract

The use of renewable fuels can reduce consumption of fossil fuels as well as diversify the range of alternative energy carriers. The advantage of biofuels is that they can be obtained from waste materials. Biofuels derived from vegetable or animal raw fatty material, as a result of transesterification, are characterized by similar physicochemical properties to mineral diesel fuel in terms of quality standards, however the fatty acid composition of the raw material can significantly influence exhaust gas emissions. The aim of the research is to determine the impact of the origin of various renewable biocomponents on exhaust gasses concentration emitted by compression ignition engine. The tests were conducted on a Common Rail, direct injection engine, operating under steady state conditions. Two kinds of biofuels produced from different fatty raw materials (rapeseed oil and swine lard) were used. All the experiments were performed on fuels containing a total of 50% biocomponent shares admixed to commercial diesel fuel. The tested samples included both: binary and ternary mixtures. During the experiments the differences in: hydrocarbons, carbon monoxide and nitrogen oxides concentrations were examined as a result of different fuel composition. The study shows that the best results were achieved for fuel containing both plant and animal biocomponents.

Schlüsselwörter

  • exhaust gas emission
  • common rail. biodiesel combustion
  • animal fat biodiesel mixtures
  • vegetable oil biodiesel mixtures
Uneingeschränkter Zugang

Engineering Support of the Quality of Surface Layer of Tab Grooves in the Discs Made From Heat-Resistant Steel

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 153 - 158

Zusammenfassung

Abstract

The main idea of the work is to create scientifically grounded technological conditions for treatment of tab grooves in the discs from heat resisting steel, which stipulate formation of roughness of treated surfaces at the level of design requirements, useful compressive residual stresses and a defective surface layer, which increases reliability of operation of interlock in the absence of any defects on the working surfaces of tab grooves of various types, under conditions of maximizing efficiency of their treatment method. Dependences of roughness of the treated surface on the technological factors of the broaching process Ra = f (V, S, γ, HRC) have been proposed. As a result of experimental studies, the nature of distribution of residual stresses, depth and degree of strengthening of the surface layer, depending on the technological conditions of the tab grooves treatment, has been established. The article presents research of surface quality parameters; study all the selected parameters of the surface quality and surface layer and an algorithm to perform experimental work. The algorithm has been built on major principles of control and fixation methods, which stipulate use of non-destructive methods of control. Graphs of strengthening the surface layer of samples, depending on their processing modes and graphs of the distribution of residual stresses in the surface layer are also presented.

Schlüsselwörter

  • surface quality parameters
  • tab grooves and interlocks
  • heat-resistant steel
Uneingeschränkter Zugang

X-ray Stress Measurements in the Institute of Aviation Possibilities and Examples

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 159 - 166

Zusammenfassung

Abstract

From the point of view of the airplane construction, its fatigue lifetime and exploitation process, the stress states and levels are of crucial importance. The most appropriate experimental methods to determine stress values are diffraction methods with different radiation type employed. These methods allow the determination of the elastic lattice deformation and distortion (effectively the stress state) from the displacement and broadening of the diffraction peak. Diffraction methods are widely known as the experimental methods for determining not only the stress values but also the elastic properties of polycrystalline materials (also of all alloys types used in the aerospace industry). The advantages of diffraction experiments result from their non-destructive character and the possibility to obtain absolute values of stresses in different phases of each type of crystal material (the measurements are performed selectively only for crystallites contributing to the measured diffraction peak, i.e. for the grains having lattice orientations for which the Bragg condition is fulfilled). In the frame of this work, the laboratory possibilities of the Institute of Aviation in this area are presented as well as the exemplary results of stress measurements performed there.

Schlüsselwörter

  • X-ray diffraction
  • residual stress measurements
  • fatigue
Uneingeschränkter Zugang

Preliminary Study of an Airplane for Electric Propulsion Testing at High Altitudes

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 167 - 174

Zusammenfassung

Abstract

Technology of photovoltaic cells and lithium batteries is being developed rapidly. As a result, attempts to build solar High Altitude Long Endurance (HALE) airplanes are more and more frequent. In the future, such airplanes may appear very useful for the economy because they may replace geostationary satellites in several applications. Unfortunately, data on altitude effect on photovoltaic cells and batteries performance are not easily available. Moreover, acquisition cost of cells is very high. Therefore, a tool for inexpensive testing of cells is needed. This article shows a study of very light unmanned airplane that could be used as a testbed for this purpose. Weight assumptions are presented together with concept of geometry and aerodynamic characteristics. Propulsion system is proposed, so also airplane performance is estimated. Finally, results are discussed leading to the conclusion. It appears that unmanned airplane with maximum take-off weight of 1.3 kg can climb to the altitude of 10 km within 4 hours during sunny summer day about the noon. However, only 30% of such days can be used because of strong winds blowing at high altitudes, quite small optimal airspeed of the airplane and constraints due to Air Traffic Management. Moreover, application of variable pitch propeller is recommended as well as some kind of take-off assist. For example, towing or take-off from the hill is desirable to avoid threats resulting from small climb rate.

Schlüsselwörter

  • Electric propulsion
  • flight testing
  • unmanned aerial vehicle
Uneingeschränkter Zugang

A Mobility Analysis of Using the Rhex-Type Mobile Robot in Various Surroundings

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 175 - 181

Zusammenfassung

Abstract

Mobile robots are becoming increasingly popular, finding a great deal of applications, especially in situations where conventional mobility systems, such as wheels or tracks, prove ineffective. Exploration of an unknown environment or a place, in which Man is incapable of staying, for example exploring remote planets in the Solar System, is often linked with operating a device in a rough terrain. This requires an adjustment of the robot locomotion system to the ground. The problem of high mobility in diverse surroundings is still a major challenge. Therefore, the concept of mobile robots is extremely popular and is still being developed. Using this type of propulsion carries several advantages, namely the possibility of applicability of this type of solutions in an environment, which is not easily accessible to wheeled vehicles (sandy, mountainous terrain, etc.). There is still a large interest of constructors and scientists in unconventional drive systems, adapted directly from nature, which often offers very efficient solutions. Quite frequently, designers copy the construction of animal locomotion system, attempting at implementing them in their designs. The aim of this article is to present an original construction, known as the Rhex-type robot in the available literature. In addition, it presents a number of conducted investigations, which describe the platform’s mobility in various terrains, such as sands, rocks and rubbles, as well as the possibility to overcome the terrain obstacles. It ends with conclusions and potential application areas of this type of a design.

Schlüsselwörter

  • mobile robot
  • Rhex
  • mobility
  • animal locomotion system
Uneingeschränkter Zugang

Android Application Used in Diagnostic System of Engineering Devices and Machines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 183 - 188

Zusammenfassung

Abstract

Users of machines and engineering devices force continuous improvement of their functionality and efficiency while reducing energy consumption. For this purpose, numerous sensors are installed in the machines in both drive systems and execution systems. Sensors are a source of information for control units and also allow reading parameters during diagnostic tests. The diagnostician should have the appropriate interface and knowledge of the operating principles of the tested machine. In order to facilitate the implementation of the diagnostic process even by less experienced service personnel, it is proposed to use a diagnostic interface based on the application developed in the Android system, which main element is a QR code scanner. The system uses MATLAB-Simulink, database and PHP script to work properly. This system allows performing a diagnostic test and identifying potential causes of device failure. The system has friendly interface where is implemented many useful things like graphs and visualization of device movement. The application reads the nominal operating parameters stored in the QR code of the machine and displays the next steps necessary to assess the technical condition of the object. On the basis of a comparison of registered and nominal machine parameters, the application indicates possible fault locations. The implementation of the database on an external server allows the application to run anywhere on android devices that have access to the internet. Through the registration process, it is possible to create a database of employees who have access to the system. The diagnostic system for storing all information, such as employee data or current sensor measurement values uses the MySQL database. Preliminary tests of the application carried out during diagnostics of the hydraulic and mechanical system of the building manipulator confirmed the functionality of the developed system.

Schlüsselwörter

  • QR code scanner
  • diagnostic interface
  • MySQL database
  • hydraulic manipulator
Uneingeschränkter Zugang

Comparative Analysis of NEDC and WLTC Homologation Tests for Vehicle Tests on a Chassis Dynamometer

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 189 - 196

Zusammenfassung

Abstract

In 2015, the number of vehicles in the world exceeded 1.1 billion units. In the coming years, it is expected that the largest increase in the number of vehicles will take place in developing countries. This is a problem in particular in terms of emissions of harmful substances from vehicles. Considering that all manufactured vehicle models have to undergo a detailed homologation and meet the exhaust emission requirements before placing on the market, it is necessary to refine test procedures, including test cycles, in which vehicle emissions are determined. At present, the NEDC approval test is valid in Europe. It is a cycle reproduced on a chassis dynamometer in steady conditions. It consists of an urban section repeated four times and an extra urban part. From 2019, a new test procedure will take effect, which uses the WLTC cycle, also reproduced on a chassis dynamometer in fixed conditions. It is much more complex and better reflects the real traffic conditions. For a better illustration of the differences that occur between the current NEDC cycle and the new WLTC, the article presents a comparative analysis of both driving cycles. This is to present the justifiability of using a new driving cycle and to present its complexity. The article presents own research of a vehicle with a spark-ignition engine, which has been tested both in the NEDC and WLTC cycle. On the basis of the obtained data, it was possible to determine the differences in the emission of harmful exhaust gas components and indicate how the new homologation procedure affects the emissions from the vehicle.

Schlüsselwörter

  • combustion engines
  • homologation procedure
  • NEDC test
  • WLTC test
  • exhaust emissions
Uneingeschränkter Zugang

Possibilities of Using a Wireless Telemetry System of a Recreational Vehicle (Off-Road)

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 197 - 203

Zusammenfassung

Abstract

The development of electronic systems has significantly contributed to the rapid increase in the number of controllers working in vehicles, and thus the amount of data transferred between them. The large amount of information sent prevents the driver from directly mastering or understanding them, hence it was necessary to limit the displayed parameters on the instrument cluster to the most important ones, so that the driver can focus on driving. However, in motor sports and in various types of road tests or research, where the driver is supported by an additional team of engineers, information sent between vehicle controllers can prove extremely valuable. Most often, the whole staff of people responsible for conducted traction tests does not occupy the vehicle, so as not to disturb the conditions. Their analysis usually takes place in a designated service spot, in which case the parameters from the on-board data transmission network are usually transmitted by radio from the vehicle to the archiving system. Therefore, research into the development of wireless data transmission systems from vehicle controllers is also carried out at the Opole University of Technology. This article describes the possibilities of using a system built at the Opole University of Technology for wireless conduction of diagnostics and analysis of current operating parameters of a recreational All-Terrain Vehicle (ATV). In addition, in the designed system, it is also possible to connect external sensors to analyse parameters normally not registered during the course on normal vehicle operation.

Schlüsselwörter

  • telemetry
  • wireless data acquisition
  • all-terrain vehicle
  • CAN bus
Uneingeschränkter Zugang

Flame Propagation in Gas Feeding Pipelines to the IC Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 205 - 212

Zusammenfassung

Abstract

Results from experimental investigation on flame propagation in a pipeline filled with gaseous combustible mixture consisted of hydrogen, methane or 20% hydrogen-methane is presented in the article. The mixture was prepared in separate cylinders and premixed before filling the pipeline. The tests were conducted under various relative equivalence ratio – lambda from 1.0 to 3.0 at pressure of 1 bar and temperature of 25ºC. Hydrogen and methane were selected because these gases are main combustible fractions in several gaseous engine fuels (e.g. natural gas, syngas, biogas). Additionally, the mixture 20% hydrogen and methane, as potential engine fuel, was also under investigation. Flame front was detected with aid of IR photodetectors. Hence, the flame speed was resulted from distance divided by time. As observed, the flame propagation speed was over 100 m/s for both hydrogen and methane premixed mixtures. It was several times higher if compared with the laminar flame speed for these gases. It can be explained by additional acoustic effects (standing waves) taking place inside the pipeline. Results from this investigation can be useful in design and construction of the gas feeding system in the gas fuelled internal combustion engine.

Schlüsselwörter

  • flame propagation
  • laminar flame speed
  • methane
  • hydrogen
  • combustion
Uneingeschränkter Zugang

Issues during Assembly New Type of Electric Brake Prototype and Initial Tests of Individual Components

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 213 - 218

Zusammenfassung

Abstract

In this article, the author focused on the two main issues. Firstly, the assembly phase of the new type of electric brake prototype was described and secondly author introduced the initial tests of individual components. The assembly phase of the new prototype of the electric brake was very significant. In this stage, the parts were fitted and mounted. The new functionality of new type prototype was checked and the designing was verified. If there were some mounting problems this was proper time to correct the dimensions and exchange parts. Sometimes the materials or even or heat treatment of some part were exchanged. In that kind of prototype, it was really important to check electric parts like motors during the load. The most important issue was to find the best solution. The motors weight should have been as small as possible and the nominal torque should have been enough for normal working of prototype. In the initial tests of individual components, the real parameters were tested and possibility of using the parts was checked too. During designing phase, the parameters were defined and the tests results gave the answers for the possibility of real working on the object. The most important parameters there were the motors parameters and the possibility of mechanism force transmission.

Schlüsselwörter

  • assembly
  • electric brake
  • prototype
  • mounting
  • new designing
Uneingeschränkter Zugang

Resistance to Aging Research in Sea Water Composites with the Polyester-Glass Recyclate

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 219 - 225

Zusammenfassung

Abstract

Composites are materials used for various types of constructions in the automotive industry, aviation, and shipbuilding. Due to the wide use of these materials, there is a problem with their recycling. Such material requires appropriate processing technology, which has been developed to obtain a recyclate with a specific granulation. The use of hand laminating technology made composites with the addition of polyester and glass recyclate with granulation of 1.2, as well as content: 0%, 20%, 30%. These types of materials are exposed to various types of atmospheric factors that affect their durability. Aging is defined as changes in the composite when exposed to atmospheric conditions, such as sunlight, temperature, thermal cycles, water in various forms and wind. This article uses recycled polyester and glass composites to investigate the effect of aging in seawater on their strength properties. These tests can be used to pre-assess the applicability of newly developed materials as construction or protective coatings. They were carried out on a specially prepared station for accelerated tests, with elevated temperature (35ºCC), as well as brine spray imitating sea atmosphere. The method is used to accelerate the aging processes occurring in composite materials. Samples were subjected to cycles of 5, 30 and 60 days respectively. Samples were weighed and measured before and after each cycle. In order to investigate the effect of aging on strength properties, the composites underwent a static tensile test in accordance with the standard for plastics. Studies have shown that as a result of the aging process, the strength properties decrease slightly, which affects the favourable assessment of these materials as constructional.

Schlüsselwörter

  • recycling
  • polyester-glass recyclate
  • aging of composites
  • tensile test
Uneingeschränkter Zugang

Laminar Burning Velocity Predictions of Single-Fuel Mixtures of C1-C7 Normal Hydrocarbon and Air

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 227 - 235

Zusammenfassung

Abstract

The numerical modelling of combustion phenomena is an important task due to safety issues and development and optimization of engines. Laminar burning velocity (LBV) is one of the most important physical properties of a flammable mixture. Knowing its exact value if crucial for assessment of flame stabilization, turbulent flame structure. It influences strongly safety, probability of knocking combustion and it is one of parameters used for assessment and development of detailed chemical kinetic mechanisms. Hence, the goal of this work is to develop models by means of Machine Learning algorithms for predicting laminar burning velocities of single-fuel C1-C7 normal hydrocarbon and air mixtures. Development of the models is based on a large experimental data set collected from literature. In total more than 1000, LBVs were accumulated for hydrocarbons from methane up to n-heptane. The models are developed in MATLAB 2018a with use of Machine Learning toolbox. Algorithms taken into account are multivariate regression, support vector machine, and artificial neural network. Performance of the models is compared with most widely used detailed chemical kinetics mechanisms’ predictions obtained with use of LOFEsoft. These kind of models might be efficiently used in CFD combustion models based on flamelet approach. The main advantage in comparison to chemical kinetics calculation is much shorter computational time needed for computations of a single value and comparable performance in terms of R2 (coefficient of determination), RMSE (root-mean-square error) and MAE (mean absolute error).

Schlüsselwörter

  • laminar burning velocity
  • hydrocarbon
  • machine learning
  • LOGEsoft
  • alkane
  • MATLAB
Uneingeschränkter Zugang

Modelling of the Over-Expanded Cycle Combustion Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 238 - 245

Zusammenfassung

Abstract

The study concerns numerical tests of an internal combustion engine operating according to the over-expanded cycle carried out in the AVL Fire software. The research covered the modelling of a full working cycle of a conventional engine operating in accordance with the classic Otto cycle and an engine operating on the basis of an over-expanded cycle – the Atkinson cycle. As part of the work, three cases of Atkinson’s cycle were analysed, by closing the inlet valve before BDC (21º before BDC) and closing the valve after BDC (41º and 75º after BDC). As a result of modelling, space-time distributions of velocity, pressure and temperature in the cylinder of the modelled engine were obtained. Optimizations of the analysed cycles were carried out, finding the best ignition timing, at which it is possible to obtain the highest efficiency and the highest indicated mean effective pressure. The calculations showed that the engine operating according to the over-expanded cycle in order to obtain the best operating parameters requires earlier ignition timing compared to the conventional engine. In addition, in the engine operating according to the Atkinson cycle, there is a drop in the indicated mean effective pressure and an increase in the indicated thermal efficiency compared to the engine operating by the classical cycle.

Schlüsselwörter

  • over-expanded cycle
  • methane
  • gas engine
  • modelling
Uneingeschränkter Zugang

Numerical Analysis of a Velocity Distribution of a Fluid Flow Inside a Reversing Chamber

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 247 - 251

Zusammenfassung

Abstract

Axisymmetric stream, which is directed into an obstacle, is an important type of a fluid flow for technical applications in a large amount of thermal and flow devices. The article presents a case wherein stream of a fluid is directed into a flat surface and changes the direction of a flow by an angle equal to 90°. After that, the free stream is changing a character of a flow into impinging stream. The article presents a methodology of numerical calculations preparation in ANSYS Fluent environment for a velocity distribution of an airflow inside a reversing chamber. Numerical calculations were prepared for a three-dimensional model as an unsteady simulation with Delayed Detached Eddy Simulation model of turbulence. A stream of an air, which was analysed inside a reversing chamber, was not initially swirled. Obtained results of realized calculations were compared with experimental analysis and numerical calculations, which was realized in a different environment by co-author. Model of reversing chamber, which was implemented into numerical analysis has the same dimensions as used in experimental research. Obtained results show areas of intense flow turbulence inside reversing chamber. Prepared numerical calculations agreed with experimental results of research and allowed to designate areas of stream core and impinging stream inside modelled chamber.

Schlüsselwörter

  • numerical analysis
  • reversing flow
  • fluent
  • axisymmetric flow
Uneingeschränkter Zugang

In-Cylinder Combustion Analysis of a SI Engine Fuelled with Hydrogen Enriched Compressed Natural Gas (HCNG): Engine Performance, Efficiency and Emissions

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 253 - 260

Zusammenfassung

Abstract

The main objective of this study was to investigate the effect of hydrogen addition on spark ignition (SI) engine’s performance, thermal efficiency, and emission using variable composition hydrogen/CNG mixtures. The hydrogen was used in amounts of 0%, 20%, 40% by volume fraction at each engine speed and load. Experimental analysis was performed at engine speed of 1200 rpm, load of 120 Nm corresponding BMEP = 0.24 MPa, spark timing 26 CAD BTDC, and at engine speed of 2000 rpm, load of 350 Nm corresponding BMEP = 0.71 MPa, spark timing 22 CAD BTDC. The investigation results show that increasing amounts of hydrogen volume fraction contribute to shorten ignition delay time and decrease of the combustion duration, that also affect main combustion phase. The combustion duration analysis of mass fraction burned (MFB) was presented in the article. Decrease of CO2 in the exhaust gases was observed with increase of hydrogen amounts to the engine. However, nitrogen oxides (NOX) were found to increase with hydrogen addition if spark timing was not optimized according to hydrogen’s higher burning speed.

Schlüsselwörter

  • Hydrogen
  • CNG
  • SI engine
  • combustion
  • emission
  • MFB
Uneingeschränkter Zugang

Combustion of RME – Diesel and NExBTL – Diesel Blends with Hydrogen in the Compression Ignition Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 261 - 274

Zusammenfassung

Abstract

The article presents the test results of the single cylinder compression ignition engine with common rail injection system operating on biofuels and conventional diesel blends with hydrogen. Two types of liquid fuels were tested: blend of the 7% Rapeseed Methyl Ester (RME) with conventional diesel fuel and Neste Pro Diesel – blend of the 15% Hydrotreated Vegetable Oil (HVO), produced by Neste Oil Corporation with conventional diesel fuel. The purpose of this investigation was to examine the influence of the hydrogen addition to biofuels and diesel blends on combustion phases, autoignition delay, engine performance efficiency and exhaust emissions. Hydrogen fraction was changed within the range from 0 to 43% by energy. Hydrogen was injected into the intake manifold, where it created homogeneous mixture with air. Tests were performed at both fixed and optimal injection timings at low, medium, and nominal engine load. After analysis of the engine bench tests and simulation with AVL BOOST software, it was observed that increasing hydrogen fraction shortened the fuel ignition delay phase and it affected the main combustion phase. Moreover, decrease of carbon monoxide (CO), carbon dioxide (CO2) and smoke opacity was observed with increase of hydrogen amounts to the engine. However, increase of the nitrogen oxide (NOx) concentration in the engine exhaust gases was observed.

Schlüsselwörter

  • hydrogen
  • RME
  • HVO
  • NExBTL
  • PRO Diesel
  • diesel fuel
  • CI engine
  • combustion
  • emission
Uneingeschränkter Zugang

Mechanical and Thermal Stresses Issues Related to a Size of a Four-Stroke Piston Based on a Renault Premium DXi11 430 460 EEV Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 275 - 282

Zusammenfassung

Abstract

The size of an engine is one of the factors affecting its thermal efficiency. It is known that with an increase of the size of the engine, the cubic capacity and heat generation grows in the third power, whereas thermal losses are proportional only to the second power of the size (due to heat exchange surface). However, the increase in the size of the engine generates some problems related to its mass, rotational speed and heat load, the last of which is a subject of these considerations. In the article, the influence of the piston size on its thermal and mechanical stresses is considered. Similar boundary conditions for both cases were assumed. Simulation of the steady-state heat transfer and mechanical simulation were carried out using the Finite Element Method. In each analysis, both the original version of the piston and its scaled version were considered. The boundary conditions were adopted on the basis of engine catalogue data and available literature. The results of analyses were discussed.

Schlüsselwörter

  • heat transfer
  • temperature distribution
  • four-stroke engine piston
  • finite element method
  • size related issues
Uneingeschränkter Zugang

The Influence of Injection Timing on the Combustion Characteristics for the Heterogeneous Combustion Field Using Impinging Injection

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 283 - 288

Zusammenfassung

Abstract

It is very important to achieve the low particulate and low emissions under high power operation conditions in practical industrial engine and turbine combustion. Several techniques for reducing the emissions have been proposed and a large amount of experimental data has been published. It is well known that the combustion field in practical industrial diesel engine are strongly influenced by the behaviour of injection, distribution of droplets and the premixed ratio of the combustion chamber. As the first step of this study, experiments have been carried out to examine the combustion characteristics of heterogeneous combustion field by using impinging injection and Split injection in a closed chamber. The combustion chamber is equipped with pintle type injection nozzles on each of the opposite walls along the length of the bomb. In this study, we call it “impinging injection” when the injection is performed at same time by two nozzles facing each other and “split injection” when the impinging injection is performed at two different timing. The main conclusions are as follows: 1) the most suitable conditions of injection timing exists for improving the maximum burning pressure and total burning time by using impinging injection; 2) the flame speed can be possible to control by using impinging injection timing from the ignition; 3) the heat release rate for Split injection is larger than that of standard impinging injection.

Schlüsselwörter

  • impinging injection
  • split injection
  • heat release rate
Uneingeschränkter Zugang

Selected Aspects of the Maintenance System Optimisation of the Polish Armed Forces Helicopters

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 289 - 297

Zusammenfassung

Abstract

The maintenance of helicopters at the airports of the Polish Armed Forces in the state of technical efficiency determines the possession – by the entity securing their maintenance, repair – of appropriate resources and the maintenance system. The article presents the current state of the operation processes of helicopters in the Polish Army. The characteristics of the helicopter maintenance system model and the basic assumptions were described, and the mathematical records of input data to the system were identified and presented. The selected elements of the optimisation task, its decision variables, and constraints were formulated. The initial assessment of the quality of the proposed solution of the helicopter maintenance system model. The essence of the system optimisation problem, which relates to minimising the cost function and maximising the system’s readiness function, was emphasised. In addition, an example of appropriateness of applying such an approach is presented on the basis of the School Aviation Base. The article was concluded with a short summary, which stressed the importance of this type of the optimisation system.

Schlüsselwörter

  • helicopters
  • maintenance system
  • optimisation of systems
Uneingeschränkter Zugang

Automatic Taxi Directional Control System for General Aviation Aircraft

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 299 - 306

Zusammenfassung

Abstract

The article presents a concept of an automatic directional control system for a General Aviation class aircraft during the taxiing phase. In particular, it shows the concept of the system and the control laws synthesis – mathematical model and simulation of taxiing aircraft. Several reasons have emerged in recent years that make the automation of taxiing an important design challenge including decreased safety, performance and pilot workload. The adapted methodology follows the model based design approach in which the control system and the aircraft are mathematically modelled to allow control laws synthesis using the Adaptive Disturbance Rejection Control method. The computer simulations are carried out to analyze the control system behavior. Chosen methodology and modelling technique, especially tire-ground contact model, resulted in a taxing aircraft model that can be used for directional control law synthesis. Aerodynamic forces and moments were identified in the wind tunnel tests for the full range of the slip angle. The results can be used for the preliminary performance assessment of the ADRC method applied in the taxi directional control system. Such system has not been introduced to General Aviation yet. Therefore, the model of taxiing aircraft including aerodynamic characteristics for the full range of the slip angle and a directional control system have a big value in the process of design and implementation of the future automatic taxi systems.

Schlüsselwörter

  • General Aviation
  • taxiing
  • automatic control
  • mechanics of flight
  • aerodynamic tests
Uneingeschränkter Zugang

The Use of Fuzzy Expert System for an Automatic Control of the Propulsion System in the Aircraft Zlin 143LSi

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 307 - 314

Zusammenfassung

Abstract

The article discusses the manner of controlling the propulsion system in the aircraft Zlin 143LSi, which is equipped with a piston engine driving a variable-pitch propeller. All the operating procedures are carried out manually by the pilot in accordance with the flight manual. The authors attempted at developing the project of a controller based on fuzzy logic, whose main goal was automating the control system of the propulsion unit, thus lowering the level of difficulty of pilotage, and increasing the economics of the operation. The project was made in an interactive environment FuzzyLogic Toolbox of the MATLAB programme. In the analysis, three input parameters were taken into account, exerting an impact on changing the rotational speed of the propeller: the charging pressure of the propulsion unit expressed in inches of mercury, the speed of the aircraft (TAS) in knots and the angle of attack, at which the flight is made, expressed in degrees. On the basis of the above-mentioned input signals, the rotation speed of the propeller was determined, by changing the blade pitch and the recommended angle of attack for the parameters in order to make an optimal use of the data of the flight conditions. The article presents the project of the controller and its optimization. The authors simulated the controller operation in the package MATLAB “Simulink”. The article ends with data analysis and final conclusions.

Schlüsselwörter

  • fuzzy logic
  • fuzzy expert system
  • propulsion system
  • aircraft Zlin 143LSi
Uneingeschränkter Zugang

Necessary Wind Tunnel Tests Conditions of Proper Two- and Three-Dimensional Measurements

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 315 - 322

Zusammenfassung

Abstract

In this article, the conditions to be met by a two- and three dimensional wind tunnel tests in order to ensure their correctness are presented. First of all, they relate to the flow similarity between the real and wind tunnel conditions. This similarity enforces a wind tunnel calibration, a proper design and manufacturing of the tested models, a proper research, as well as processing of obtained test data including the usage of the wind tunnel corrections. In this work, the majority of these conditions were presented but in particular, the influence of the wind tunnel corrections on the tested models aerodynamic characteristics is consider. The two-dimensional airfoil studies and three-dimensional aircraft model balance investigation were performed in two low speed wind tunnels of a different sizes of theirs test section. The wind tunnel tests were performed in two Institute of Aviation low speed wind tunnels, namely in the wind tunnel T-1 (of the 1.5 m diameter test section) and in the wind tunnel T-3 (of the 5 m diameter test section), at the same undisturbed velocity, V∞ = 40 m/s. The comparison of the lift coefficient characteristic obtained in two different wind tunnels using the same two and three-dimensional models and same measurement techniques enabled to discuss the problem of necessity of the wind tunnel corrections usage.

Schlüsselwörter

  • applied aerodynamics
  • tests reliability
  • aerodynamic measurements
Uneingeschränkter Zugang

The Evaluation of the Fiat 0.9 TwinAir Engine Powered by Petrol and LPG Gas Work Cycles Uniqueness

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 323 - 330

Zusammenfassung

Abstract

The article describes the test results of the uniqueness of the work cycle of two-cylinder internal combustion piston FIAT 0.9 TwinAir engine, while being powered by 95 octane petrol fuel and LPG gas. The engine was working according to load characteristics. The engine mounted on the test bench was equipped with a sequential LPG gas fuel supply system. The gas fuels differ significantly from the petrol fuels in their physiochemical properties. In order to rationally utilize gas fuels to power internal combustion engines, the knowledge about basic fuel burning process of these fuels is required. The article shows the analysis of individual engine work cycles of the technologically advanced engine in order to evaluate the influence of powering by LPG gas fuel on the rate of uniqueness of its work cycles. The measure of uniqueness of the inter-cylinder processes are the work cycle uniqueness indicators, which are as follows: the maximum work cycle pressure uniqueness indicator, the average measured work cycle pressure uniqueness indicator, the measured pressure work cycle graph uniqueness indicator and the measured pressure work cycle partial graph uniqueness. The carried out research and its analysis has shown that powering the engine with LPG gas has an influence on the engine work cycles and its uniqueness. The burning process of the mixture consisting of air and LPG gas is quicker, which has an effect on the higher speed of pressure increase rate in comparison with the engine being powered by petrol fuel. Achieved maximum in-cylinder pressure values while the engine was powered by LPG gas were higher in comparison with it being fuelled with conventional fuel. This causes an increase of the gas lads on crank-piston system, which are influencing directly the piston with higher heat load, and the thermal load of the engine.

Schlüsselwörter

  • spark ignition engines
  • gas engines
  • gasoline engines
  • uniqueness of work cycle of internal combustion engine
  • indicator diagram
Uneingeschränkter Zugang

Application of Similarity Method of Distance Courses Describing the Elements Content in Cement Concrete after Frost Resistance Test

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 331 - 337

Zusammenfassung

Abstract

The work concerns test results of cement concrete and the use of similarity analysis of distance course. Research procedure was presented and the obtained laboratory tests results were discussed. Composition of concrete mixes was designed. The cement concrete composition includes cement, coarse aggregate, fine aggregate, water, admixtures and a ceramic addition. The addition of ceramic was used as a replacement for part of the fine aggregate Fresh concrete mixture parameters were tested and basic parameters of hardened concrete were defined (density, compression strength and tensile strength). The scope of works included concretes intended for airfield pavements and this concretes after frost resistance test. The test has been conducted in diversified media generally used in the course of winter maintenance. Subject to observations of internal structure of concretes and conducted chemical microanalyses using scanning electron microscope, the contents of diversified elements in four zones were specified. The following zones were subject to analysis: cement matrix, contact area between air pores and cement matrix, contact area between fine aggregate and cement matrix and contact area between coarse aggregate and cement matrix. Based on the results obtained diagrams similarity of the analysed concretes were prepared.

Schlüsselwörter

  • airfield pavements
  • cement concrete
  • ceramic additive
  • frost resistance
  • analysis of similarity
Uneingeschränkter Zugang

Device for Control the Valvetrain and Cylinder Pressure of a Spark-Ignition Engine

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 339 - 346

Zusammenfassung

Abstract

This article describes the method of controlling an electric magnetic linear actuator that moves an inlet valve of an internal combustion engine. Thanks to the use of the electric control of the inlet valve of the internal combustion engine, it was possible to implement a variable effective compression ratio of the operating power unit, adapting it to the current needs and engine load. In this design, valvetrain was modified by introducing an autonomous intake valve operation with the use of a specially designed electromagnetic actuator. The introduction of this system necessitated an additional modification of the intake camshaft. The control was carried out with the use of a real-time controller with a built-in FPGA unit. The proposed design of a system with an electromagnetic actuator will allow obtaining an additional degree of freedom in the control unit. Particular attention should be paid to registered values or air pressure in the intake stroke for a closed or partially opened throttle, which generates significant pumping losses. The use of an electromagnetic actuator in the intake can help reduce said losses.

Schlüsselwörter

  • combustion engines
  • environmental protection
  • variable compression ratio
  • valve control
Uneingeschränkter Zugang

Preliminary Analysis of Thermodynamic Cycle of Turbofan Engine Fuelled by Hydrogen

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 347 - 354

Zusammenfassung

Abstract

Presented article is focus on analysis of the effect of hydrogen fuel on turbofan engine performance. Selected properties of hydrogen and possibility of introduction in civil aviation were discussed. Hydrogen implementation as aviation fuel offers obvious advantages such as low emission of combustion product, higher payload, lower fuel consumption, general availability but also poses great technical challenges. The most important aspect is to ensure engine operational safety at very high level. Hydrogen implementation would eliminate the aviation dependence of exhausting sources of fossil fuels especially of crude oil. The thermodynamic model of turbofan engine was implemented in MATLAB environment. Accepted assumptions have been discussed. Turbine cooling process has been included in the numerical model. Working fluid was modelled as semi-perfect gas. Analysis was carried out for take-off and design point conditions. Engine performances were compared for two kinds of applied fuels: liquid hydrogen and commonly used in turbine engines kerosene. Combustion heat of hydrogen is about three time higher than in comparison with conventional turbine engine fuel, what exert significant influence on engine performance. The results of engine thermodynamic cycle analysis indicate the increase in specific thrust and significant reduction of specific fuel consumption. The results are presented in tabular form and on the graphs. Obtained results have been discussed and the direction of further research was indicated.

Schlüsselwörter

  • liquid hydrogen
  • turbofan engine
  • turbine cooling
  • engine thermodynamic cycle
  • engine performance
Uneingeschränkter Zugang

Analysis of the Influence of the Changes in the Value of Dynamic Viscosity Coefficient in the Direction of Oil Film Thickness on the Journal Bearing Load Carrying Capacity

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 355 - 362

Zusammenfassung

Abstract

This article presents the results of numerical calculations of the hydrodynamic pressure distribution, load carrying capacity, friction force and friction coefficient of the slide journal bearing, if the assumed model of hydrodynamic lubrication takes into account the dependence of oil viscosity values on its temperature in all three directions of the adopted coordinate system, in particular, also across the thickness of the lubricant layer. This research considered the slide journal bearing lubricated with the Newtonian oil. The flow of oil was modelled as laminar and stationary. The bearing bushing had a full angle of wrap and its surfaces were smooth. In order to obtain hydrodynamic pressure distributions, the Reynolds type equation was numerically solved by application of the finite difference method (FDM). The numerical procedures for this research were prepared with the Mathcad 15 software. When adopting the classic models and simplifications for the hydrodynamic lubrication and a thin boundary layer, it is assumed, that the hydrodynamic pressure of lubricating oil does not depend on the position measured across the height of the lubrication gap. On the other hand, it is known, that the dynamic viscosity strongly depends on the temperature, which is a function of all three spatial variables. The aim of this work is to include, in the hydrodynamic lubrication model, the changes of viscosity in the direction of oil film thickness, and to investigate how it will affect the hydrodynamic pressure distribution and load carrying capacity of the journal bearing.

Schlüsselwörter

  • slide journal bearing
  • load carrying capacity
  • friction force
  • friction coefficient
  • numerical calculation
Uneingeschränkter Zugang

Measurement of Axial Motions of Piston Rings in a Two-Stroke Engine by Using Back Light of LED

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 363 - 369

Zusammenfassung

Abstract

In two-stroke engines of the crankcase-compression type, the piston rings slide over not only the cylinder wall but also the cylinder ports. It is important for piston ring designers to understand how piston rings behave over cylinder ports. In order to clarify the axial motion of piston rings in two-stroke engines, we established a measurement method using light-emitting diodes (LEDs). We attached LEDs inside the piston, and leaked the backlight of LEDs through the side clearance between the piston ring side face and the piston ring groove side face. From the position of the leaked backlight in the piston ring groove, we determined the axial ring position in the ring groove. Our experiments set this piston with LEDs in an experimental two-stroke engine with a transparent cylinder, and investigated the effects of intake and exhaust ports on axial ring motion under motoring operations. Results indicated that the rings moved in the axial direction by the ring projection and catching in the intake and exhaust ports.

Schlüsselwörter

  • two-stroke engine
  • piston ring
  • cylinder port
  • axial motion of piston ring
  • LED
  • transparent cylinder
Uneingeschränkter Zugang

Analysis of the Wind Dependent Duration of the Cruise Phase on Jet Engine Exhaust Emissions

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 371 - 376

Zusammenfassung

Abstract

Nowadays more and more attention is paid to minimizing the costs of air operations. The largest share in the cost of the flight is the cost of consumed fuel. Taking into account the external conditions, having impact on the aircraft, such as wind direction and magnitude when planning the aircraft trajectory it is possible to reduce flight time and thus reduce fuel consumption. An additional advantage is the simultaneous reduction of pollutants in the jet engines exhausts. In the times of pro-ecological trends and concepts (e.g. Clean Sky, Single European Sky, CORSIA) this aspect is of crucial importance. The emission of selected pollutants in the jet engine exhausts (NOx, CO and HC) emitted during the flight of a business jet on the route whose cruise phase was assumed 1000 km long was determined in the article. The aircraft used in the research was Gulfstream GIV, powered by two Rolls Royce TAY 611-C engines, for which a cruising altitude of 10 km and a flight speed of 0.8 Ma were assumed. The thrust necessary for the flight at these cruise parameters was set, and then the engine thrust appropriate for the flight and the corresponding specific fuel consumption were determined. On this basis, based on the available ICAO data, the emission of selected pollutants in tis engines exhausts was determined for windless conditions. Next, the analysis of the impact of wind - its magnitude and direction – on the emission of these pollutants was made. The results of the conducted analyses are presented in diagrams and discussed in the conclusions.

Schlüsselwörter

  • air transport
  • jet engines
  • air pollution
  • emission
  • exhausts
  • wind impact
Uneingeschränkter Zugang

The Importance of Mixture Preparation for Industrial Heat and Power Gas Engines

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 385 - 392

Zusammenfassung

Abstract

The main task of a gas mixer is to mix the fuel (gas) with air in such a way that in the gas engine optimal combustion takes place. A high efficiency of the whole combustion process and low emissions are the decisive optimization parameters. An industrial gas engine operates mostly with a lean air-gas combustion mixture with an air excess coefficient ratio of → λ=1.6. Most often heat and power industrial gas engines operate with biogas. The biogas is produced by anaerobic digestion, where biodegradable materials in the absence of oxygen are fermented. That is why the biogas fuel consists mostly of methane → CH4 (up to 70 [%]), carbon dioxide → CO2 and traces of other contaminant gases. It is well known, that the performance of industrial gas engines strongly depends on the quality of air and fuel mixing and therefore homogeneity of the mixture. Improper air-gas mixture can lead to unstable operation of the entire gas engine and excessive emissions beyond the applicable environmental standards. Therefore, in this article numerical investigations were performed using the open source computational fluid dynamics software OpenFOAM to show the importance of mixture preparation for industrial heat and power gas engines by describing in detail the mixing behaviour in a Venturi gas mixer model.

Schlüsselwörter

  • gas engine
  • environmental friendly power generation
  • combustion processes
  • mixture preparation
Uneingeschränkter Zugang

Experimental Studies of Leading Edge Vortex Control of Delta Wing Micro Aerial Vehicle

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 393 - 402

Zusammenfassung

Abstract

It is known, that small disturbances generated by the micro actuators can alter large-scale vortex structures, and consequently, generate appreciable aerodynamic moments along all three axes for flight control. In the current study, we explored the possibility of independently controlling these moments. We perform analytical simulations showing optimal position of LEX generators, and water tunnel measurements showing effectiveness of MEX generators as MAV control devices. We applied array of actuators located on either the forward or the rear half section of the leading edge. Both one- and two-sided control configurations have also been investigated. Experimental results showed that asymmetric vortex pairs were formed, which leads to the generation of significant torques in all three axes. The article presents typical vortical flow over a delta wing, water tunnel at Wroclaw University of Technology, experimental setup and procedures, static test results on water tunnel testing including normal forces, pitching and yawing moments, maximum values of rolling, pitching, and yawing moment coefficients, effectiveness of pitching and yawing control.

Schlüsselwörter

  • Micro Aerial Vehicles
  • Unconventional control effectors
Uneingeschränkter Zugang

A Method of Engines’ Diagnosis in Operation

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 403 - 410

Zusammenfassung

Abstract

It was found that there are discrepancies between the values of diagnostic parameters obtained in the test and natural exploitation. In addition, no appropriate tests are carried out which would be based on the degree of engine degradation in long-term natural use. One of the reasons is the lack of adequate, non-invasive diagnostic methods. The aim of the work was to show the possibility of creating a new diagnostic parameter of combustion engines in their natural operation. The parameter can be determined by a new method (presented in the article). The method is based on the assumption that the technical condition of the engine can be judged on the basis of the run-up curve, and in particular, on the basis of the linear direction coefficient, which is approximated by the points of the run-up curve at particular moments of the run-up. An additional requirement is that the points of the run-up curve are the average value of the speed from many runs. In addition, the statistical distributions of the speed values in the individual moments of the run-up should be of the same type. The direction coefficient of the straight line determined is a diagnostic parameter. The value of the new coefficient is the value of the straight-line factor. Further works are underway to determine the relationship between the directional coefficient and the technical condition of the engine.

Schlüsselwörter

  • transport
  • combustion engine
  • engine diagnostic
  • diagnostic methods
  • engine technical conditions
Uneingeschränkter Zugang

Influence the Applied Control Structure on Energy Efficiency of the Hydrostatic System

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 411 - 418

Zusammenfassung

Abstract

A control system with a proportional directional throttling control valve or a directional control servo valve, controlling a cylinder (linear hydraulic motor) is used in the ship steering gear drive, in the controllable pitch propeller control, in the variable capacity pump control system for hydraulic deck equipment motors or fixed pitch propellers in small ships (for example ferries). The hydraulic system is designed first of all taking into consideration the nominal parameters of the cylinder load and speed. For such parameters, the energy efficiency of the elements and complete system is described. Meanwhile the exploitation conditions can vary in full range changes of the cylinder load and speed coefficients. The article presents a comparison of the energy behaviour of two widespread structures of hydrostatic systems: a standard individual systems with a throttling steering fed by a constant capacity pump. Both hydraulic solutions are described and equations of the total efficiency η of the system are presented. Diagrams of energy efficiency of two hydraulic systems working at the same parameters of a speed and a load of hydraulic linear motor, which were different due to structure are presented and compared, as well ability of energy saving. This publication also presents analyses and compares the areas of the power fields of energy losses occurring in the elements of two hydraulic systems with different structures of the hydraulic linear motor speed control.

Schlüsselwörter

  • energy efficiency
  • power of losses
  • hydrostatic system
  • throttling steering
  • pump
  • hydraulic linear motor
  • proportional directional valve
  • deck machinery
Uneingeschränkter Zugang

Research on the Effect of Diesel Fuel Injection Parameters on the Combustion Process in the Turbocharged CI Engine Operating on Propane

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 419 - 429

Zusammenfassung

Abstract

Results presented in the article regard the research on a turbocharged dual-fuel CI engine operating on propane. The research indicated that such engine might operate even if 70% of the standard fuel energy is replaced by propane. The research indicated that at such high share of the gaseous fuel, there is necessary to adjust diesel fuel injection parameters but it is important that there is no need to change the engine structure. Injection parameters may be adjusted in a wide range due to the modern fuelling system of the common rail type. The investigated engine was equipped with such system. Adjustments regarding the fuel charge division, fuel charge quantities, and injection timing enabled to influence combustion in such way to obtain its specific parameters, i.e. maximum combustion pressure, rate of pressure rise, maximum pressure, and the burn out ratio similar to those obtained for diesel fuel operation. The obtained results were presented in form of adjustment characteristics of the injection timing of diesel fuel pilot dose for a few chosen values of the boost pressure as well as injection timing of the main dose. The investigations were carried out for three values of the boost pressure, i.e. 200; 400 and 600 [mbar] but also for the naturally aspirated version. Injection timing of the first dose varied in a broad range and depended on the boost pressure. Injection timing of the second dose varied in a narrower range, mainly due to considerable changes in the combustion process. The obtained results answered a number of questions regarding the strategy of selection of diesel fuel injection parameters taking into consideration engine performances as well as combustion at a high share of the gaseous fuel.

Schlüsselwörter

  • combustion engines
  • dual fuel
  • propane
  • control of injection parameters
Uneingeschränkter Zugang

LoRaWAN Networks in Automotive Applications

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 431 - 435

Zusammenfassung

Abstract

Development of IoT is tightly coupled with the use of the wireless communication solutions. Nowadays there are several standard wireless protocols, which are responsible for carrying information. The increase of the communication traffic tends to specialize the kind of used data interchange methods for the sake of demanded size of data packet, frequency of connections, meaning of the data, security and safety of the transmission as well as many others. One of the intensively spreading wireless networks is LoRaWAN. Because of its low energy consumption, long distance range, and high flexibility, it seems to be very effective solution to apply in the field of road traffic. The article presented the base features of LoRaWAN as well as the conception of virtual local traffic system based on the data yield from the board systems of cars. Accessed from OBD information about f. e.g. temporary cars speed or accelerations associated with their current position can be significant factor in creating the real image of the traffic situation.

Schlüsselwörter

  • automotive
  • communication networks
  • car parameter monitoring
  • CAN
  • modular system
Uneingeschränkter Zugang

Simulation of Rime Icing and Its Effects on Aerodynamic Characteristics of an Airfoil

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 437 - 443

Zusammenfassung

Abstract

A mathematical model for simulation of icing dedicated to simulation of ice accretion and its effects on aircraft aerodynamic characteristics in conditions of rime icing is presented. Pure rime icing occurs at lower temperatures than glaze icing and results in higher roughness of the surface of deposited ice. The model accounts for increased surface roughness, in terms of equivalent sand grain roughness, caused by deposited rime ice, which influences generation and dispersion of heat in the boundary layer. Increase of surface roughness is determined by analytical models created upon experimental data obtained in icing wind tunnels. Increased generation of heat is a result of increased tangential stress on the surface and is quantified in the temperature recovery factor determined numerically by a CFD solver. Effects of surface roughness on the intensity of forced convection are quantified by application of Colburn analogy between heat and momentum transfer in the boundary layer, which allows assessment of heat transfer coefficient for known friction coefficient, determined by CFD. The computational method includes determination of the surface distribution of mass of captured water in icing conditions. The model of freezing of captured water accounts for generation of heat due to latent heat of captured water droplets, temperature recovery in boundary layer and kinetic energy of captured droplets. The sinks of heat include forced convection, heating of super cooled droplets, conduction of heat through the ice layer and sublimation. The mathematical model is implemented as user-defined function module in ANSYS Fluent solver. The results include effects of deposited ice, including increased surface roughness on aerodynamic characteristics of an airfoil.

Schlüsselwörter

  • computational fluid dynamics
  • aerodynamics
  • two-phase flow
  • simulations of ice accretion
  • heat exchange
  • aircraft engineering
  • transport
  • vehicles
Uneingeschränkter Zugang

Level of Manipulation of Digital Recording Devices in Light of Introducing ERRU System in European Countries

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 445 - 452

Zusammenfassung

Abstract

The tachograph is the oldest recording device, which belongs to the Group of ORD (On Board Recording Devices). It was introduced in the USA in 1939. Digital tachograph, the new advanced type of recording device in road transport, was introduced by Council Regulation No 2135/98 of 24 September 1998 with the beginning of May 2006, in the area of the European Union. “In contrast to its analogue predecessors the digital tachograph was introduced to facilitate the control of rest and driving times and to prevent manipulation attempt. In order to prevent abuse, it has been made the system of cryptologic keys and certificates stored in cards and devices, allowing creating explicit laws of users and authentic data recorded in, cards and devices. The Hasler Event Recorder was introduced in the 1920s. Regrettably, the construction of analogue tachograph, an original type of tachograph is used in road transport, encouraged to numerous frauds and counterfeits of social rules for drivers. Secure digital tachograph system is indisputably a means having the great influence on road safety, enforcement of the social conditions for drivers in road transport as well as supporting the fair competition between road transport undertakings. In order to better monitor the compliance of road transport with the rules in force, inter alia the provisions on usage the digital tachographs, the European Union regulation introduces the European Registers of Road Transport Undertakings (ERRU), a system that allows a better exchange of information between Member States.

Schlüsselwörter

  • digital recording device
  • procedure
  • safety
  • system
  • European Registers of Road Transport Undertakings
Uneingeschränkter Zugang

Influence of Internal Space Frame in Body Shell on Change of its Response as a Result of Impulse Forcing

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 453 - 458

Zusammenfassung

Abstract

In order to increase the stiffness anybody chassis in Wheeled Armoured Vehicle on impact of the shock wave, the space frame part in body shell was conducted. The aim of this action is to reduce deformation and damage as a result of the detonation of the mine or an Improvised Explosive Device (IED) under the vehicle. To verify the conducted modernization, numerical calculations of the system response to a blast wave effect were carried out. The mass of the detonated explosive was increased from 6 to 20 kg of TNT. An explosive material was detonated centrally under the vehicle front part according to NATO requirements [1, 2]. The results of the calculations allowed for a deformation assessment of the floor plate and its displacement before and after modernization. A model and numerical calculations were performed using the following software: CATIA, HyperMesh, LS-PrePost, LS-Dyna. CONWEP approach was used to describe an influence of a pressure wave on the structure.

Schlüsselwörter

  • blast wave
  • Light Armoured Vehicle (LAV)
  • CONWEP
  • chassis
  • space frame
  • body shell
Uneingeschränkter Zugang

Multi-Parametric and Multi-Objective Thermodynamic Optimization of a Spark-Ignition Range Extender ICE

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 459 - 466

Zusammenfassung

Abstract

The current legislation pushes for the increasing level of vehicle powertrain electrification. A series hybrid electric vehicle powertrain with a small Range Extender (REx) unit – comprised of an internal combustion engine and an electric generator – has the technical potential to overcome the main limitations of a pure battery electric vehicle: driving range, heating, and air-conditioning demands. A typical REx ICE operates only in one or few steady-states operating points, leading to different initial priorities for its design. These design priorities, compared to the conventional ICE, are mainly NVH, package, weight, and overall concept functional simplicity – hence the cost-effectiveness. The design approach of the OEMs is usually rather conservative: parting from an already-existing ICE or components and adapting it for the REx application. The fuel efficiency potential of a one-point operation of the REx ICE is therefore not fully exploited. This article presents a multi-parametric and multi-objective optimization study of a REx ICE. The studied ICE concept uses a well-known and proven technology with a favourable production and development costs: it is a two-cylinder, natural aspirated, port injected, four-stroke SI engine. The goal of our study is to find its thermodynamic optimum and fuel efficiency potential for different feasible brake power outputs. Our optimization tool-chain combines a parametric GT-Suite ICE simulation model and modeFRONTIER optimization software with various optimization strategies, such as genetic algorithms, gradient based methods or various hybrid methods. The optimization results show a great fuel efficiency improvement potential by applying this multi-parametric and multi-objective method, converging to interesting short-stroke designs with Miller valve timings.

Schlüsselwörter

  • Range Extender
  • hybrid electric vehicle
  • battery electric vehicle
  • internal combustion engine
  • spark-ignition
  • thermodynamic optimization
  • genetic algorithm
Uneingeschränkter Zugang

Statistical Analysis of Ground-Related Incidents at Airports

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 467 - 472

Zusammenfassung

Abstract

In recent years, the aviation sector has been developing dynamically. The constant increase in the number of passengers contributes to an escalation in the number of air operations. This trend is mainly due to the increased traffic not only in airspace but also within airports. The large concentration of aircraft at the largest airports makes ground-flying phases such as taxiing or take-off becoming a challenge for pilots, ground services, and air traffic controllers. An intensive operation of many objects on the airport's manoeuvring areas can lead to collisions between them. Global air traffic is growing constantly, with record numbers of air operations and passengers carried. The probability of a collision increases, which leads not only to the cancellation of the flight but also to the significant costs of the aircrafts repair. The statistical analysis allows to highlight the problems related to the issue of ground collisions at airports and can also confirm the thesis concerning the growth and density of air traffic.

Schlüsselwörter

  • air transport
  • statistical analysis
  • airports incidents
Uneingeschränkter Zugang

Effects of Renewable Energy Sources on Air-Fuel Ratio

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 473 - 477

Zusammenfassung

Abstract

Environmental emission of road transport is a key problem. Periodic environmental test are designed to ensure minimum emission. Periodic checks are based on measurements. In this emission measurements fuel type plays an important role. The Brettschneider equation is a method used to compare the idealized and actual air fuel ratio. Brettschneider established a method to calculate ratio of oxygen to fuel by comparing the ratio of oxygen molecules to carbon and hydrogen molecules in the exhaust. In this article, authors have investigated blended ethanol effect on idealized and actual air fuel ratio based on Brettschneider equation. The main result of the article that blended ethanol has insignificant effect on air-fuel ratio. The article presents inter alia difference in stoichiometric air fuel ratios in case of different fuels, changes in λ due to blending ethanol and comparison of influence of emissions of different types of transport. In the article authors focus particularly on periodic checks and gasoline driven cars. The main research question was if ethanol blends have effect on idealized and actual air fuel ratio based on Brettschneider equation.

Schlüsselwörter

  • air-fuel ratio
  • lambda
  • gasoline
  • ethanol
  • combustion engines
  • air pollution
  • environmental protection
Uneingeschränkter Zugang

Wind Power Plants – Types, Design and Operation Principles

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 479 - 487

Zusammenfassung

Abstract

Many countries worldwide support green energy production on large scale mostly by solar or wind energy subsidizing manufacture and operation of such systems. During the last two decades, there has been significant increase in wind energy production globally. Statistics show continuously growing investments in the development and installation of wind turbines and farms. Currently, wind energy is the second most important source of renewable energy after water energy. By 2016 global cumulative installed wind capacity surpassed 432 k MW [GWEC]. In last several years, most dynamic growth in wind power generation investments was recorded in Asia. Europe, in comparison, has less impressive but steady growth in wind power plants through the years. In this article, authors present global demand on energy in comparison to efficiency of wind power plants in relation to the local and global location as well as to the scale of installed system. Authors also present statistical data concerning wind power plants development. General classification, using number of criteria (ex. power output, construction size, rotor axis orientation and other) of wind to electric power converting devices is presented. Various types of devices, which authors describe in this article, can perform conversion of wind blow energy to the electric energy using different yet similar methods.

Schlüsselwörter

  • wind energy
  • wind power plants
  • energy conversion
  • renewable energy
Uneingeschränkter Zugang

Area of the Unstable Solution of Rolling Equation – Jumps of the Oscillations Amplitude

Online veröffentlicht: 10 Oct 2019
Seitenbereich: 489 - 496