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 24 (2017): Heft 3 (September 2017)

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

Suche

41 Artikel
Open Access

The Possibilities and Development of In-Cylinder Catalytic Coating

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 7 - 14

Zusammenfassung

Abstract

Due to the legal changes in the exhaust emission limits in the European Union meeting the new norms becomes more challenging for car manufacturers. The recent progress in the exhaust aftertreatment technology and commercially available aftertreatment systems. However, as the exhaust, systems become more and more complex the problem of high emissions in many engine-operating points that are not currently a part of the type approval tests remains. The article aims to address the limitations of the oxidation catalysts in current aftertreatment systems, mainly their light-off temperature, by investigating new options for in-cylinder catalysts. Placing the catalytic layer within the combustion chamber avoids a number of problems associated with these catalysts being a part of the aftertreatment system. Engine emission tests have been performed comparing the effects of using an in-cylinder Pt-Rh catalytic layer in relation to hydrocarbon and nitrogen oxides emissions. The viable methods of producing a catalytic layer on engine components along with the choice of components to use for catalytic surfaces have also been discussed.

Schlüsselwörter

  • combustion engine
  • in-cylinder catalyst
  • exhaust emissions
Open Access

Engine Fuel Characterisation Through Ultraviolet Absorption Spectra

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 15 - 19

Zusammenfassung

Abstract

In the article, light absorption properties of the fuel oil are considered with a view to create basis for establish optical indicator of the type and quality of this kind of crude oil derivative, in this case the Diesel fuel. The organic solvent – n-hexane – was chosen as a solvent to prepare samples of dilutions of Diesel fuel in several oil concentration. Spectrophotometer Aqualog Horiba were applied to record the absorbance spectra in the ultraviolet and visual range of the light (from 240 to 600 nm) for each previously prepared samples. Obtained results allow concluding that the changes of absorbance occur primarily in the wavelength range from 240 nm to 355 nm. Moreover, the absorbance spectra are characterized by the characteristic sharp peak located at 270 nm for excitation wavelength. Spectra of absorbance were converted to spectra of absorption coefficient based on Lambert-Beer law. Due to the independence the absorption coefficient from the fuel concentration, this parameter could be used as a potential indicator to access composition and quality Diesel fuel used in the diesel engine system. Therefore, preliminary tests allow concluding that absorption coefficient for selected wavelength located at 270 nm could be a sensitive indicator for quick access to fuel quality.

Schlüsselwörter

  • fuel
  • spectroscopy
  • absorptivity
  • diesel engine system
Open Access

Idea of Use of Hydraulic Booster in High-Pressure Fuel Pump with Hypocycloid Drive

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 21 - 28

Zusammenfassung

Abstract

Common rail (CR) injection systems have been universally applied in passenger car engines for twenty years. Moreover, they are applied on a wide scale in trucks, machinery and stationary engines. They have many advantages such as very good fuel spraying due to high injection pressure, injection dose distribution to several smaller, or less heat generation compared to traditional systems. At the same time, the use of this type of system involves a number of problems. They are characterized, among other things, by the high cost of manufacturing and the high sensitivity to changes in the quality of the used fuel.

The most important component of the common rail injection system is the high-pressure injection pump. The authors propose a new, alternative pump design with the hypocycloid drive – the article presents the issue of using this type of pump. Further sections describe the design of a pump utilizing a hypocycloid mechanism; demonstrate beneficial functional features and present selected results of the assembly’s dynamic simulation.

The pump is also characterized by the possibility of multiplying the piston’s pitch while maintaining its diameter. It makes it possible to obtain much greater discharge per operating cycle. Taking into account the considerable quantity of fuel transferring by the pump, was also possible to propose an idea of use of hydraulic booster in such pump. In this field, the authors have presented schematic diagram of a pressure booster with a description of its operation.

Schlüsselwörter

  • high-pressure fuel pump
  • hypocycloid drive
  • hydraulic booster
  • common rail
  • simulation
  • combustion engines
Open Access

Research Injection Pressure with the Kistler 4067E Pressure Transmitter on Sulzer Engine 3AL25/30

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 29 - 36

Zusammenfassung

Abstract

Commonly used in the shipbuilding are combustion piston diesel engines that serve as power generators and main propulsion engines. More stringent of environmental regulations, however, require a more detailed understanding of the processes involved in piston engine combustion to reduce emissions to the environment. Also, the main reason for interest in research in the injection system is also the desire to obtain the highest piston engine power at the lowest fuel consumption. The article presents a study of changes in fuel injection pressure, which allows the operator to analyse the thermodynamic processes taking place in the cylinder. The injection pressure measurement allows you to make proper operating, maintenance and even repair decisions on the object under test. The purpose of this article is to investigate the operation of the injection pressure sensor and to compare the pressure curves measured by the Kistler 4067E sensor in various piston engine-operating states and the simulated failures of the SULZER 3AL25/30 diesel engine. The study was conducted on the SULZER 3AL25/30 engine at the Marine Engine Laboratory at the Gdynia Maritime University. Tests carried out with a measuring instrument for sampling are equipped with a Kistler 4067E pressure transducer, a Kistler 4624A amplifier and a Unitest 2008 computer system serviced with a recorder, processing and signal recording. For a thorough analysis, research conducted at different loads and different simulated engine failure.

Schlüsselwörter

  • diesel
  • engine
  • marine engine
  • injection pressure
Open Access

CFD Analysis of Influence of Axial Position of Shaft on Hydrodynamic Lubrication of Slide Conical Bearing

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 37 - 44

Zusammenfassung

Abstract

During the operation of a slide bearing, the position of its shaft or sleeve varies due to many factors, such as vibrations, load changes, changes in the lubricating viscosity. The vibrations or varying load can cause, that the position of the bearing shaft, measured along its axis of rotation, changes. This is particularly important for sliding bearing with conical geometry. Due to the geometry of this kind of bearing, i.e. where the radius of this bearing (of the shaft and sleeve) has not a constant value, as in the case of a journal bearing, it is more difficult to obtain proper values and describe its hydrodynamic lubrication.

This article shows the results of hydrodynamic lubrication of the slide conical bearing, for which the changes in the position of the bearing shaft in the longitudinal direction, i.e. along its axis of rotation, were taken into account. The commercial CFD software, designed for solving general for flow phenomena problems, was used in the simulations. This article shows the results of simulations, assuming that the lubricating oil behaves as a generalized Newtonian fluid. The hydrodynamic pressure distributions, load carrying capacities and friction torques were calculated for the concerned bearing.

The aim of this work is to show how the operating parameters of the slide conical bearing can be influenced, by only changes of the position of the shaft along the axis of its rotation.

Schlüsselwörter

  • hydrodynamic lubrication
  • conical bearing
  • slide bearing
  • radial clearance
  • CFD
Open Access

Influence of Selected Parameters on Micro Gas Turbine Compressor Design

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 45 - 52

Zusammenfassung

Abstract

The design a micro gas turbine engine is a process that requires analysis of a number of parameters. The initial stage requires consideration of more than 40 parameters [3]. The whole analysis can be made with analytical tools. However, these kinds of tools are limited to preliminary designs. After 1D-calculations and the establishment of the first CAD model, it is recommended to identify the sensitivity of the design. With a modern numerical environment such as ANSYS CFX, it is possible to predict a trend that gives the designer a 3D feedback about the initial design behaviour. For presented centrifugal compressor case, the selected parameters are vaneless diffuser space, design angle and number of stator blades. For qualitative evaluation – important results that influence design are mass flow rate, total pressure and isentropic efficiency. These results are important to turbojet engine performance and efficiency. All chosen parameters respond to given criteria. Validation and verification is still required due numerical errors that are included in CFD modelling. The advantage of 3D prediction is the possibility to eliminate gross errors before parts are sent into production.

Schlüsselwörter

  • jet engine
  • gas turbine
  • design
  • trend prediction
  • centrifugal compressor
Open Access

Experimental and Numerical Three-Point Bending Test for Sandwich Beams

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 53 - 62

Zusammenfassung

Abstract

The article deals with an experimental investigation of mechanical properties of sandwich beams obtained from bending tests. The tested specimens consisted of foam or honeycomb core and face sheets made of aluminium alloys, plywood or composite material. The face sheets and the core were bonded with glue material. Beams of different dimensions, namely beam width, as well as core and face sheets thickness, were tested. Three point bending tests were carried out, which mid span deflections of the beam versus applied force were recorded. Experimental test results were compared with simulations on the basis of finite element method. The full, non-linear analysis, taking into account large displacements and using contact elements was performed. The obtained results are presented in load-deflection diagrams. Some conclusions concerning ultimate loads and failure behaviour of tested beams made of different materials have been derived.

Schlüsselwörter

  • numerical simulation
  • bending tests
  • composite materials
  • sandwich beams
  • honeycomb
Open Access

The Burnishing Process of the Stainless Steel in Aspect of the Reduction Roughness and Surface Hardening

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 63 - 69

Zusammenfassung

Abstract

In the article were presented influence of technological parameters of burnishing process on the degree of hardness and reduction roughness. Burnishing process carried out for stainless steels X2CrNiMo17-12-2. The experimental research were obtained in the surface layer increase in hardness and the material ratio curve a convex shaped, which, taking into account the load capacity of the surface will be directly affected by its resistance to wear and corrosion. The experimental research by application of the burnishing rolling – pressuring process (BRP) method were made in the Laboratory of Production Engineering at the Department of Marine Maintenance at the Faculty of Marine Engineering at the Gdynia Maritime University. After the studies it was found that the hardness of the surface layer and the roughness of the shaft necks an important influenced by technological parameters of processing (burnishing speed, feed and depth of burnishing). The objective of applying burnishing process may be, for example, the need to increase surface smoothness and dimensional accuracy of part. To achieve the objectives strengthen and smooth of burnishing stainless steel should be used the one pass burnisher roller and feed fn = 0.2 mm/rev and disk burnishing tool feed an = 1.0 mm and burnishing speed vn = 70 m/min.

Schlüsselwörter

  • burnishing rolling – pressuring process (BRP)
  • surface roughness reduction ratio
  • degree of relative strain hardening
  • stainless steel
Open Access

Model Testing of the Internal Leaks of Valve Body in Automatic Transmission

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 71 - 78

Zusammenfassung

Abstract

The article presents the working conditions and the functions of the ATF fluid in an automatic transmission. It was noted that the correct operation of the automatic transmission is heavily influenced by the quality of the ATF fluid, which operates in disadvantageous conditions of oxidising environment, is subject to contamination and undergoes intense shearing, thus changing its physical and chemical properties during use. The analysis included the disadvantageous, from the point of view of loss of fluid pressure in the automatic transmission’s hydraulic system, phenomenon of the fluid’s flow through fractures (clearances) of the hydraulic precise pairs “called the rate of flow through internal leaks” or an “internal leak”. The model of the rate of flow through internal leaks was proposed to determine the impact of the precise pairs’ wear and the hydraulic fluid’s properties on the aggregated leaks in the hydraulic system controller of the automatic transmission. The modelling utilised the dependency between the rate of flow through internal leaks of the hydraulic precise pair and the coaxial circular fracture. The model’s assumptions were formulated. The values of clearances of the electrohydraulic controller’s precise pairs were determined during the measurements of the actual structure – based on the automatic transmission’s mileage. The measurements featured relevant diameters of pushers and sliders, as well as internal diameters of cylindrical openings of manifold sliders and hydraulic suppressors. Variant model testing was conducted with various degrees of the fluid’s wear and temperature (viscosity and density) for conditions of driving with transmission “1” and “2”.

Schlüsselwörter

  • automatic transmission
  • hydraulic system
  • hydraulic precise pair
  • wear of hydraulic couplings
  • internal leaks
  • ATF fluid flow rate model
Open Access

Ecological and Economic Conditions for Implementing Hydrogen Fuel

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 79 - 86

Zusammenfassung

Abstract

Hydrogenation of the motor transport has become the highest form of broadly understood contemporary electro mobility, with the use of hybrid vehicles through fully electrical vehicles to fuel cell vehicles. This article presents development of hydrogen technology applying fuel cells, in particular in road transport.

The emission of greenhouse gases in the production cycles of the said fuel were discussed, depending on the use of various energy carriers in its production. Emphasis was given to the rationale underlying the production of hydrogen for the needs of fuel cells. Furthermore, the advantages were presented of exploiting electrical power for the production of hydrogen with the use of renewable sources of energy. The example of France was used to discuss the advantages of the hydrogen fuel technology for reducing the emission of combustion pollutants, in particular the emission of carbon dioxide.

The article also evaluates – on the example of Poland – average unit costs (PLN/km) for using fuel cell vehicles. At present, they will be higher than in case of vehicles with conventional drivers. High cost is one of the causes – apart from limited production of fuel cell vehicles – of slacked development of the hydrogen fuel technology. The article also presents premises for the road transport hydrogenation national plan in Poland.

Schlüsselwörter

  • road transport
  • hydrogenation
  • ecological
  • economic conditions
Open Access

Nitrogen Oxides Emission Estimator for a Diesel Engine Use to Reduce the Emission of Harmful Substances in Exhaust Gas to Environment

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 87 - 94

Zusammenfassung

Abstract

This article reports the results of experimental and numerical analysis of emissions of nitrogen oxides in exhaust gas to the environment from a turbocharged diesel engine of a tractor. The problem of identifying nitrogen oxides emissions from the exhaust gases was formulated and subsequently solved, based on data gained from measurements. The results of estimation of nitrogen oxides emissions were verified on the basis of research on a test object. The object of the study and a non-linear static model of nitrogen oxides emission were also described for two systems – with and without exhaust gas recirculation. The article demonstrates that the use of an adequately selected mathematical model can lead to the estimation of emissions of nitrogen oxides contained in the exhaust gas of diesel engines in an off-road vehicle. The created model can be used to control the valve of the exhaust gas of recirculation system and so reduce the emission of harmful substances to the environment. The presented research results show the comparison of estimated and measured nitrogen oxides concentration. The estimated value from the mathematical model concentration is about from 0.7 s to 1 s earlier than the value measured by the sensor, therefore the exhaust gas recirculation system could be controlled accordingly before nitrogen oxides are formed.

Schlüsselwörter

  • nitrogen oxides emission
  • diesel engine
  • estimation
  • combustion engines
  • air pollution
  • environmental protection
Open Access

Utilization Possibility of Marine Trent 30 Gas Turbine as Prime Mover on Vessels

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 95 - 100

Zusammenfassung

Abstract

Gas turbines are used as marine prime movers but the market is dominated by the diesel engines (of course turbocharged but they are still diesels). The share of gas turbines is on a level of 4-5% in the worldwide shipping.

It was presented the chosen parameters of Rolls-Royce gas turbine MT30 with nominal power 36 MW or 40 MW prepared for marine utilization. It is a good example of development of marine gas turbines with the trial to eliminate the effect of ambient temperature especially on turbine load.

It was discussed the significance presented data for possibility of utilization on vessels. It was indicated the advantages and disadvantages of gas turbine sharing.

It was mentioned the installation problems: pressure drop in inlet and outlet ducts on the accessible turbine power and specific fuel consumption.

It was discussed what important parameters ought to be known for safe turbine operation and maintenance. There is a little information lack. The gas turbine ought not to be treat as a black box. In the end, some final remarks are presented.

Schlüsselwörter

  • marine prime mover
  • gas turbine
  • propulsion
  • gas-electric plant
  • gas turbine utilization
Open Access

Automated Guided Vehicles – The Survey

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 102 - 110

Zusammenfassung

Abstract

Transport has always been a fundamental impulse for the development of civilization. The first fully automatically controlled vehicles for industrial application (previously called driverless vehicles) was design in 1954 year. This has been achieved more than 60 years ago. Unmanned Ground Vehicles are a whole family of autonomous vehicles use modern tools with all power today available electronics for navigation task and decision making process on the base artificial intelligence and (AI) algorithms. At present time a problem of the realization a fully reconfiguration navigation system working in real time mode for UGV vehicles is the subject of the research for many scientific units of the entire scientific world. The object of the statement constitute AGV short historical outline with actual trends marking. The special authors’ attention was focused on the solutions dedicated for so-called e-tools functionalities implementing in modern AGV vehicles. The main purpose of the article was focused on the set of issues involving the most problems in the whole material handling (MHD) family devices with any autonomous factor. The article is focused on the localization problem, trajectories founding, path planning, scheduling, workspace with environment mapping and AGV control issues. Described methods and tools are connected with chosen artificial intelligence solutions dedicated or adapted for autonomous vehicles’ needs.

Schlüsselwörter

  • AGV
  • navigation
  • patch planning
  • scheduling
  • workspace mapping
  • control
  • telematics
Open Access

Mathematical System Model for Acoustics Based Telematic Micro Services in Iot for Transportation Setting

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 111 - 118

Zusammenfassung

Abstract

Despite the wide adoption of Internet of things (IoT) with several webs standards and cloud technologies, building of city wide IoT based smart city platform for solving transportation problem remains a daunting task. Owing to the dynamic nature of IoT and components of transportation systems, smart city architecture would require development of a scalable, distributed and evolving architecture on the web. With the advancement in autonomous transportation system there is a need for in adaptive telematic system for communicating with other vehicles, sensor nodes etc. As transport, services have special requirements of which are related to the size and type of information to be exchanged between vehicles (vehicle-to-vehicle communication) and the control centre. . By the time the data makes its way to the cloud for analysis, the opportunity to act on it might be gone. Thus handling such huge streams of data on the fly is a daunting task. In the study we present an interoperable swarm, logic based mobile terminals running multimedia micro services based telematic system.

Schlüsselwörter

  • Telematic micro services
  • Acoustics based Internet of Things
  • Telematic
  • Smart City
Open Access

Structure of Transport Model on Strategic Level of Management for Assessment of its Configuration

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 119 - 126

Zusammenfassung

Abstract

The aim of the article is to present the issues related to the use of the transport model for ex-ante evaluation of the functional and operational configuration of ITS. Variants of ITS configuration have been presented based with use of ITS user needs from FRAME methodology and with use of ITS user services implemented in cities of Poland. The structure of the transport model on strategic level of traffic management has been presented in the context of the following impact of ITS configuration: changes in the use of paths in network, changes in the use of transport system modes, changes in the destinations of trips, and changes in the number of trips for various purposes. The results of transport model enable a comparison, using an incremental method, results of transport decisions of users, obtained in specified forecast horizons for the ITS variants of configuration. Structure of transport model presented in article is suitable for strategic level of traffic management with long-term results. While transport models for tactical level of traffic management with medium-term results, and for operational level of traffic management with short-term results are used to determine the characteristics, describing traffic conditions in a transport network, for example expected smoothness of traffic flows, and to determine dynamic characteristics describing for example information spread processes in dynamic traffic networks.

Schlüsselwörter

  • ITS configuration
  • intelligent transport systems
  • transport model
  • ITS user services
  • ITS configuration
Open Access

Maritime Radio Information Systems

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 127 - 134

Zusammenfassung

Abstract

The article presents and evaluates the technical and operational possibilities of the maritime radio communications systems to be used especially for the exchange of information between the land users and ships. The basic functional requirements and regulations for Global Maritime Distress and Safety System (GMDSS) referring to the maritime radio information systems, resulting from the provisions of the International Convention for the Safety of Life at Sea (SOLAS) and Radio Regulations have been described. The article presents the role of information systems in the shipping and GMDSS as well. A current status of the maritime radio communication systems responsible for the exchange of information between the land users and ships has been presented. Operational and technical characteristics of the maritime radio systems used for the exchange of safety information and ships’ operating information have been described. The analysis of the systems responsible for broadcasting to the vessels the Maritime Safety Information (MSI) has been made. In this context, the operation, methods and ranges of broadcast of the Maritime Safety Information by the NAVTEX system and Inmarsat SafetyNet system have been discussed. The analysis of the systems responsible for the ships’ operating communications has been made too. The article also outlines the future of maritime radio information systems. In this context, two projects currently being implemented in the framework of the International Maritime Organization (IMO) by the Sub-Committee on Navigation, Communications, Search, and Rescue (NCSR) have been presented. The first of these projects under the name of e-Navigation refers to the use of the latest information and communication technologies in shipping. The second one concerns the modernization of the GMDSS. It is expected that as the outcome of these project works, among others, new maritime radio information systems presented here will be adopted.

Schlüsselwörter

  • communication systems
  • maritime safety communication
  • ships’ operating communication
Open Access

Experimental Testing of the Vehicle Heating System

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 135 - 141

Zusammenfassung

Abstract

An important problem in the design of machinery and equipment at the stage of determining their structure is the issue of providing adequate thermal comfort to users while operating in variable climatic and environmental conditions. This issue is of particular importance because all types of machinery and devices are equipped with very expensive and automated control and monitoring system, which should guarantee adequate warming conditions and should work under different climatic conditions. Examples of these tendencies are special solutions for vibroacoustic insulation of the inside of the devices, special air conditioning equipment, special constructions, ergonomic inside solutions. The process of shaping the discussed structural design of vehicles in terms of meeting the relevant technical and operational criteria is currently being increasingly realized through experimental tests of prototypes supported by numerical calculations. The purpose of this paper is to present the methodology of conducting test stand as a stage for the experimental determination and verification of temperature distribution, the location of heating and air conditioning devices in a prototype vehicle in variable climatic conditions (minus 15ºC). The research was carried out in a large-scale climate chamber. It covered the process of heating up the passenger area of the bus and the time of temperature stabilization on the inside of the vehicle while operating the heating systems. An additional attempt was made to test the heating system while the vehicle was in motion and to open the vehicle door to simulate the stopping of the vehicle at the bus stop. Another aspect that was analysed was the impact of the installed convector on the vehicle when the liquid heater was off.

Schlüsselwörter

  • heating system
  • temperature distribution
  • temperature tests
  • thermal chamber
Open Access

Ecological Indicators of the Perkins 1104D-E44TA Engine After Its Adaptation for Being Powered with Natural Gas and Diesel Fuel

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 143 - 150

Zusammenfassung

Abstract

The contemporary progress of automotive industry and transportation is determined to a large extent by the increasing environmental requirements, aimed at limiting the harmful impact of vehicles upon human life and people’s health. A crucial issue linked with operating vehicles is the exhaust gases generated by internal combustion engines. In order to reduce this hazardous impact upon the natural environment, the construction of the engines is continuously improved, electronic controlling is being developed for managing the course of working processes taking place in cylinders and auxiliary systems, exhaust gases cleaning systems are being developed, alternative fuels are being sought for and the possibilities of their optimal use are being examined. Natural gas is the fuel that is highly expected and hoped to be used more widely for powering internal combustion engines in vehicles. This article presents the values of selected ecological indicators of the Perkins 1104D-E44TA Diesel engine, powered by compressed natural gas and Diesel fuel (CNG + ON). For comparison reasons, the engine was powered with both fuels at the same time and then only by Diesel fuel (ON) in the same working conditions. Before the tests, the powering system control unit had been calibrated so as to enable obtaining similar values of torque while the engine was powered with the Diesel fuel only and with both CNG and ON while working with external speed characteristics; the calibration was also set up to allow for the maximum share of the natural gas in the total fuel amount supplied into the engine cylinders without engine knocking. When powering the engine with both CNG and Diesel fuel, the concentration levels of nitric oxides and carbon dioxide in exhaust gases were lower. However, the total content of hydrocarbons in the exhaust gases grew multiple times, and the content of the carbon monoxide was significantly increased. In addition, the obtained measurement results of the smokiness of the exhaust gases and the content of the soot with the engine powered with two fuels were not satisfactory.

Schlüsselwörter

  • piston combustion engines
  • engine fuels
  • harmful exhaust gases components
  • bi-fuelling
  • natural gas
  • experimental tests
Open Access

Validation of Selected Presented Method Measured of Length Fatigue Gap on Compressor Blades Forming During Resonant Tests

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 152 - 158

Zusammenfassung

Abstract

In this work, the validation of selected presented method measured of length fatigue gap was shown. The article describes three methods of determining fatigue gaps. The object of the study was the first stage compressor blade from aircraft engine. Blades have defects on the leading edge. This defect on the blade (as a result of the resonance vibration) was the origin point of the fatigue gap. Two of the methods, fluorescent and thermovision, were optical. The fluorescent method was a direct measurement, whereas direct-indirect thermography. The last of the presented methods was an analytical method, showing an algorithm based on amplitude-frequency characteristics. The advantages and disadvantages of these methods were compared. As a result of the analysis performed by the algorithm, there were specified patterns defining the dependence of change in crack length depending on the asymmetry of AF characteristics. The accuracy of the following methods and the results obtained for chord length were determined. Thanks to such use, these results have a utilitarian meaning. Such a compilation allowed us to evaluate the usefulness of particular measurement methods. Proposed methods of measuring the length of fatigue crack are used in experimental studies. It is also possible to implement them for research conducted during the operation of an aircraft engine.

Schlüsselwörter

  • crack propagation
  • gap
  • thermovision
  • turbine engine
  • blades
Open Access

Description of Strength of Wood Composite in Compound State of Load

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 159 - 165

Zusammenfassung

Abstract

All constructions are subject to the most compound loads and therefore a suitable effort hypothesis should be used for their calculation. For anisotropic materials, a hypothesis should be used to describe the properties of such materials. In the work have been shown the strength of the layers composite on the example of construction wood in a compound stress state. Wood composite is an orthotropic material. Wood is composed of alternating layers of soft wood and hard wood. Single layers are monotropic material. The use of a stress hypothesis, which describes the strength of an orthotropic material, requires will make an investigation. Studies is purposed to determine the tensile strength along and across the fibres. The compressive strengths along and across the fibres and the shear strength. Particularly the determination of shear strength requires special tooling so that in the case of flat samples in the measuring part it is possible to determine the shear stresses. Therefore, a research stand was designed and constructed. Known stress hypotheses for anisotropic materials have been analysed. The analysis showed that the strength of the wood composite could be described by the Tai-Wu stress hypothesis. Based on the results of the research, numerical calculations were performed. Calculations allowed determining the distribution of stresses in the sample measuring part. The results tests and numerical calculations have shown that obtaining a homogeneous stress (shear) condition for anisotropic materials is very difficult. Wood belongs to materials whose mechanical properties depend on many parameters, so the description of the effort of this material is a compound issue. Studies have shown that wood reinforcement by polymer saturation is best suited to the compressed loaded structures.

Schlüsselwörter

  • compound state of stress
  • modified wood
  • effort criterion
  • strengthening of the material
Open Access

The Economic Dimension of the Electromagnetic Process – Comparison Study of Costs of Repairs of Electric Vehicles and Powered with Conventional Fuels

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 167 - 172

Zusammenfassung

Abstract

The development of electro-mobility in Poland is one of the inevitable processes awaiting the Polish automotive industry. For each potential electric vehicle user, the information on the vehicle’s operating costs therefore becomes an imperative of tremendous importance. The analysis of market prices of passenger cars clearly indicates that the costs of acquiring a new electric vehicle are much higher than conventional fuel vehicles. Therefore, the expectations of customers themselves become fundamentally significant, who in relation to the spare parts in the case of this category of vehicles expect the highest technological and quality standards while maintaining the suitable price parameter.

The article attempts to signal the issues related to the evaluation of electro-mobility parameters by presenting the comparative study of the costs of repairing electric vehicles and vehicles fuelled by conventional fuels. Considerations were supplemented by authoritative cost simulations, including the comparison of the same models of vehicles equipped with both the conventional and ecological power units. The aim of the article is to draw attention to the essence of the research problem and to answer the question whether the total costs of operating electric vehicles are in reality significantly lower than that of vehicles fuelled by conventional fuel.

Schlüsselwörter

  • electro-mobility
  • alternative power sources
  • conventional fuels
  • operating costs
  • economic dimension
  • repair costs
  • spare parts
Open Access

Analysis of General Aviation Domestic Air Traffic Structure in Controlled Airspace of Poland with Refer to Sesar 2020, PJ.06-02 Project Solution

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 173 - 180

Zusammenfassung

Abstract

Civil air traffic in Poland is organized in accordance with international regulations provided by International Civil Aviation Organization (ICAO). Flight operations are performed in controlled airspace (CAS) or uncontrolled airspace. The division contains different approach to flight planning (FP) and group specific types of airspace users (AUs) and aircrafts types. Typically, General Aviation (GA) operations are placed in uncontrolled airspace while airline operations in CAS. This practice results from air operations types and aircrafts flight performance. GA includes sport, school, private transport or business flights and therefore the uncontrolled airspace with its vertical border form the ground to FL 95 contains most of the GA operations. However, there is a part of GA operations performed in CAS according to Instrument Flight Rules (IFR). The aim of the work is to describe the structure of domestic GA operations in IFR flights in CAS of Poland. Using the archival air traffic data from previous five years (2012-2016) the defined subject was analysed. In the first part, the aircraft fleet is presented. It contains the description of aircrafts types with relation to route distances, number of flights, propulsion type and wake turbulence category (WTC). In the second part, the network of defined air traffic was shown. It contains data about departure and destinations airports, the airports loading, month statistic of flights and trend in traffic changes. The traffic data are obtained from Eurocontrol database Demand Data Repository (DDR2) and using the NEST Eurocontrol software. The article arose during author’s traineeship in Eurocontrol within a framework of SESAR 2020 project, PJ.06-02 solution. Presented analyses are useful from the FP point of view since the PJ.06-02 solution refers to “Management of Performance Based Free Routing in lower Airspace” and need to consider the features of every airspace users.

Schlüsselwörter

  • general aviation
  • controlled air traffic
  • SESAR 2020
  • IFR flights
  • domestic flights in Poland
Open Access

Mathematical and Graphical Modelling of Aerobatic Flight Trajectories

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 181 - 187

Zusammenfassung

Abstract

The article presents the current state of knowledge related to mathematical and graphical modelling of aircraft trajectories, particularly those of aerobatic flights. The first part of the article is an introduction to the subject of training and aerobatic flight. In the second chapter of this work, the authors describe the basic definitions related to mathematical modelling, rules for glider aerobatics (rules for the pilots and for the judges) and specification of navigation software, which is using during competitions. In the further part of the article the authors present example possibilities of application of the mathematical modelling tools in General Aviation and describe the possibilities of implementing the obtained models in selected navigation and tracking systems. In the same part of the article there is a description of the AeroSafetyShow Demonstrator PL – an intelligent system of flights supervision and safety (ASSD+PL), which will be using to compare the real flights trajectory and the models build trough the mathematical software. ASSD+PL in also only tracking system using by the judges at glider aerobatic World Championships. The aim of this article is to validate the applicability of the system comparing to the actual aircraft trajectory with the models referred to as ‘ideal’ for aerobatic purposes.

Schlüsselwörter

  • mathematical models
  • flight trajectory
  • aerobatics
  • flight safety
  • glider aerobatics
Open Access

Selected Problems of Real Driving Emissions Measurement

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 189 - 196

Zusammenfassung

Abstract

The article compares driving test data using the latest legislative proposals applicable to passenger cars. Real Driving Emissions procedures have been introduced in the Commission Regulation (EU) 2016/427. Currently, quantitative RDE requirements have been established to limit emissions from exhaust systems in all operating conditions in accordance with the road emission limits set out in Regulation (EC) No. 715/2007. Several measurements were performed on the same test route in accordance with the RDE test guidelines, which requires a number of criteria to be met. These criteria include the length of the measuring segments, their overall test timeshare, and the dynamic characteristics of the drive. A mobile device for reading the EOBD System information was used to record the engine and vehicle operating parameters during tests. This allowed for the monitoring of parameters such as: load value, engine speed and vehicle velocity. The obtained results were then analysed for their compatibility with the RDE procedure requirements. Despite the same research route, the obtained results were not the same. The analysis also uses the two-dimensional operating time-share characteristics expressed in vehicle velocity and acceleration co-ordinates. As a result, it was possible to compare the dynamic properties, share of operating time and, consequently, to check the validity of conducted drive tests in terms of their practicability and emission values.

Schlüsselwörter

  • exhaust emissions
  • road test
  • real driving emissions
  • environmental protection
Open Access

The Environmental and Social Costs of the Intermodal Transport of Semi-Trailers By Rail

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 197 - 201

Zusammenfassung

Abstract

The dynamic development of transport recorded in recent decades is an important factor in the economic development of the world on the one hand, and on the other hand, it is a significant source of nuisance and environmental problems. The adverse impact of transport can be felt both in the natural environment and in society, where the dynamic development of this sector has enabled significant civilization development, with the effects varying depending on the level of economic development, the degree of advancement and use of the various transport sectors, geographical location (including climate), and also the sensitivity of the elements of the environment. Considering contemporary transport hazards, it is important to prevent them from occurring, and when that is not possible – limiting their impact on the environment and reducing the scale and extent of negative impacts.

In the article, the environmental and social nuisance of transport of goods loaded in semitrailers was analysed. The transport of semitrailers using intermodal wagons pulled by the diesel locomotive in accordance with the assumptions adopted in the railway with the maximum length of train composition was taken into account.

Schlüsselwörter

  • railway
  • intermodal transport
  • semi-trailer
  • environmental costs
  • social costs
Open Access

Carrying Capacity and Friction Forces in a Transverse Journal Bearing, Lubricated with Non-Newtonian Oil

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 203 - 210

Zusammenfassung

Abstract

In this article, the authors present the results of numerical calculations. Calculations concern dimensionless carrying capacity and friction forces in a transverse journal bearing, lubricated by the oil of non-Newtonian properties. For analytical-numerical considerations a model of apparent viscosity changes based on exploitation time, pressure, temperature, shear rate was assumed The non-Newtonian properties of lubricating oil were characterized by increasing viscosity with increasing shear rate and described as an additional part in the constitutive equationβ3·tr(A12)A1.

Analytical-numerical calculations were performed for smooth, non-porous plain bearing with full angle of wrap. Non-isothermal, laminar and fixed flow of lubricant in the lubrication gap of the journal bearing was assumed. Numerical calculations of hydrodynamic pressure distribution were made for Reynolds boundary conditions. The finite difference method was used to determine the Reynolds equation and the successive approximation method by taking into account the influence of pressure, temperature and non-Newtonian properties on the change of apparent viscosity. The results of the calculations are presented in the form of graphs and tables illustrating the influence of relative eccentricity and pressure, temperature and non-Newtonian properties on changes in the dimensionless load and friction force. Analysis of the obtained results illustrates the high-pressure effect on the increase of the carrying capacity and friction force for high relative eccentricities. A similar situation is by considering the non-Newtonian properties.

Schlüsselwörter

  • slide journal bearing
  • hydrodynamic pressure
  • load carrying capacity
  • friction force
  • non-Newtonian oil
Open Access

Model of Vehicle Electric Drive System

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 211 - 220

Zusammenfassung

Abstract

Models of electrical energy storage devices – a battery and a supercapacitor – as well as models of motor and a control system, were used to feature the work of a hybrid electric drive system. The models were adapted to simulate driving with a given driving cycle, in a quasi-static method, with the use of MATLAB-Simulink software. The advantage of this method is that calculations can be done quickly and results can be easily compared.

A battery model enables determining voltage and charge level in relation to load current and temperature. The basic parameter of a battery is a nominal capacity. It is a measure of energy stored in the battery, which can be absorbed within discharge time, in conditions of temperature and current. The energy can be absorbed until the minimal voltage is reached in the clips. The article presents simulation of calculations lead that the described electric drive model. The model makes it possible to analyse different concepts of steering the whole system already in the initial phase. In particular, the article presents PMSM model and trajectories of selected parameters during a trapezoidal driving cycle.

Schlüsselwörter

  • transport
  • electric vehicle
  • energy storage
  • electric drive
  • driving cycle
  • battery model
Open Access

Intensity of Motor Trucks Operation Versus Vehicles’ Age, in Several Categories of Engine Cubic Capacity

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 221 - 228

Zusammenfassung

Abstract

Changes in the vehicle operation process, which take place with vehicle’s age, have been analysed on the grounds of data collected for over 3 000 motor trucks of more than 3 500 kg gross vehicle mass (GVM), being now in use in Poland. The analysis has covered a 20-year vehicle operation period (referred to as “service life planned”); the distance travelled by a vehicle during this period has been called “target mileage” (expressed in kilometres). As a measure of the intensity of vehicle operation, the “monthly mileage” has been adopted. The monthly mileage values specified in the article strongly depend on the category of engine cubic capacity. Some important characteristics of the mileage growth process, noticed in the recent years along with an intensive development of the road transport, have been presented. The vehicle mileage growth process has been shown for four categories of engine cubic capacity, on the grounds of regression lines based on a polynomial model.

The vehicles with engines of more than 10 000 cm3 capacity reach more than 1/3 (i.e. 34.7-36.6%) of their target mileage for the first 60 months of operation, while covering only 2-5.3% of this target mileage during the last two years of their 20-year service life planned. During the first 5 years, the intensity of operation of vehicles belonging to this engine capacity category is four to five times as high as that determined for the last 5 years of the 20-year vehicle operation period under analysis. Calculations carried out have shown that the dataset under analysis includes vehicle categories where 90% of the target mileage is reached as early as after 69-70% of the service life planned. This shows that motor vehicles having been used for a short time predominate in the road transport of goods in Poland and that there is an interrelation between the rates of changes in the vehicle operation intensity and the engine capacity.

Schlüsselwörter

  • motor vehicle operation management
  • motor truck mileage
  • intensity of vehicle operation
Open Access

Control of Fiat Multiair Valve-Lift System Using Atmega Microcontroller

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 229 - 236

Zusammenfassung

Abstract

The article presents a device based on the ATmega microcontroller for precise Fiat MultiAir valve-lift system control. The Fiat MultiAir system is the patented electromechanical actuation system of the inlet valves. It allows a control of the inlet valves open time for each combustion chamber independently. The described device has been installed in the Fiat 0.9 TwinAir CNG 80 HP internal combustion engine controlled by the ECU Master open motor controller. As the ECU Master Controller software and hardware does not support Fiat’s MultiAir system control, the above-mentioned device had to be designed. The device consists of the ATmega88 microcontroller, which analyses the signals from the shaft and the cam sensors. Then, the DC converter is powering the solenoid valves of the MultiAir system via two transistors. When the solenoid valve is closed, the incompressible hydraulic fluid transmits the inlet-cam lobe’s motion to the valve as in a traditional engine. When the solenoid valve is open, the oil bypasses the passage, decoupling the valve, which then closes conventionally via spring pressure. In order to find the specific moments of turning the solenoids on and off the measurements on the original Fiat motor controller have been performed. The acquired oscillograms have been analysed and presented in the article. Studied Fiat 0.9 TwinAir engine is a part of the power generation unit and has been coupled with the three-phase electric power generator MeccAlte 16 kW with an AC exciter.

Schlüsselwörter

  • Fiat MultiAir system
  • valve-lift system
  • variable valve timing
  • open motor controller
Open Access

Aerodynamic Interference Between Pusher Propeller Slipstream and an Airframe – Literature Review

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 237 - 244

Zusammenfassung

Abstract

In the article, an aerodynamic interference between pusher propeller slipstream and the airframe of the aircraft powered by it has been presented, based on a literature study. A pusher propeller is one of popular types of the airplane propulsion. It is applied mainly in light sport aircrafts, in the UAVs (Unmanned Aerial Vehicles), unorthodox vehicles, like compound helicopters, canard and joined wing aircrafts etc. The main advantage of pusher propeller is that the engine with the pusher propeller does not affect the visibility from the cockpit and allows placing an electronic equipment in the front part of the UAV’s fuselage. Furthermore, reduced cabin noise and increase in stability due to acting normal force aft of the centre of gravity are other benefits of this configuration. The pusher propeller impact on the airframe, especially on the wing, is qualitatively different from the tractor configuration. Main differences between both propulsions has been discussed, as well as aerodynamic benefits of the pusher propeller – like reduction of separated flow area and extending area of laminar boundary layer. However, an application of pusher propeller may have also negative impact, especially lower performance than tractor propeller. In the article the reasons of this suppression has been briefly discussed.

Schlüsselwörter

  • air transport
  • air propulsion
  • pusher propeller
Open Access

Experimental Research on Identifying Data for Modelling Special Purpose Vehicles

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 245 - 252

Zusammenfassung

Abstract

The work presents selected results of experimental research on special purpose vehicles used on military training grounds, and bench tests of their main structural elements. The results are connected mainly with identifying the main vibration parameters of those vehicles (regarding weight, resilience and damping), and with the assessment of the level of dynamic loads. The more output data experimental research provides, the more input data we have for designing models. Determined in laboratory tests, weight parameters (regarding weight and moments of inertia), coefficients of stiffness and damping, as well as selected resilience and damping characteristics, are applied in the process of creating the numerical models of assemblies, systems, and complete vehicles. The numerical models created are subject to full verification in order to minimize the differences between the real objects and their representations. The models are applied in multivariate simulation tests of the existing design solutions, upgrading them, or creating new designs. Due to a certain sensitivity of the range of special purpose vehicles, the results of experimental tests and simulation analyses presented in the work are mainly qualitative rather than quantitative.

Schlüsselwörter

  • special purpose vehicle
  • combat vehicle
  • loads
  • experimental research
  • modelling
Open Access

Security of Telecommunications Systems in Transport

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 253 - 260

Zusammenfassung

Abstract

The article presents the selected elements affecting reliability and security of the telecommunications networks, which support transport services. In terms of telecommunications security, the selected methods and mechanisms, which allow providing the required level of reliability and availability of the telecommunications networks, in the fault-free operation and emergency modes, were discussed. In the article, attention was paid to the impact of a way of operation and maintenance on security of the telecommunications networks, and also on a correlation between the telecommunications system security and the security culture within the administrative and decision-making bodies.

The telecommunications networks used in transport ensure the broadly understood safe provision of data transmission services. Telecommunications networks consist of hardware and software systems, and the data transmission security depends both on hardware and software. It is a set of methods and mechanisms, which provides a high level of the system’s reliability and availability by selecting the appropriate system structure.

Schlüsselwörter

  • security
  • transport
  • telecommunications
  • reliability
  • availability
Open Access

A Novel Device with Variable Friction for Shock and Vibration Control

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 261 - 268

Zusammenfassung

Abstract

In this article a passive system, which exploits the properties of the Coulomb friction and leads to high affordability of controlling shocks and vibrations by means of cheap devices is presented. The friction force developed by the proposed device is dependent on the motion stroke by convenient modulation of contact force between the elements of friction coupling. For providing the system self-centring properties or necessary vertical load capacity, coil springs can be incorporated into the device structure. The device hysteresis characteristic can be simply adjusted to comply with requirements of the considered application. A general mathematical model of device dynamic behaviour is developed and applied to shock and vibration isolation systems.

The article presents a novel passive device with variable friction which hysteresis force-displacement characteristics have “butterfly” shape, achieved by appropriate design of friction coupling. This shape of hysteresis loops can mitigate the drawbacks of constant friction devices. The schematic of mechanical systems to analyse the dynamic behaviour of shock and vibration isolation systems with variable friction device are shown.

Schlüsselwörter

  • variable friction
  • hysteresis
  • shock and vibration isolation
  • simulation
Open Access

Water Emulsions of Hydrocarbons as Diesel Engines Fuel

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 269 - 274

Zusammenfassung

Abstract

Testing of internal combustion engine engines with hydrocarbon emulsions with water has its tradition. Previous attempts have been made using emulsions obtained chemically. This article presents similar results with the fact that emulsions of water and fuel were obtained using the cavitation phenomenon. The studies included standardized tests and non-standard measurements of polycyclic aromatic hydrocarbons (PAHs) emissions. The author, at the Wroclaw University of Science and Technology (Department of Vehicle Engineering) has developed a specific cavitator, which has been used to make emulsions of mineral and synthetic hydrocarbons. Both fuels (mineral and synthetic hydrocarbons) and their emulsions, with a water content of twenty percent (by volume), were used for testing. The engine ESC test conditions were developed. The engine was tested under the conditions of this test. Emissions of exhaust gas components (including polycyclic aromatic hydrocarbons) and fuel consumption were determined. It has been found that the use of emulsions leads to a reduction in the consumption of hydrocarbons. It has also been found that the engine power emulsion leads to a significant reduction in the emission of carcinogenic aromatic hydrocarbons, the highest concentrations of which in the exhaust gas are determined when the engine is powered by mineral diesel. Concentrations of other, considered “neutral”, polycyclic aromatic hydrocarbons changed with respect to some as they rose, others diminished, and others remained at a constant level. The “neutrality” of these hydrocarbons is due to the fact that the effects on living organisms were evaluated for each hydrocarbon separately. In exhaust gas, however, they always occur in groups, which mean that it is necessary to explain their influence when they are in coincidence.

Schlüsselwörter

  • cavitation
  • emulsions
  • IC engines
  • fuel consumption
  • emissions
Open Access

Verification the Mathematical Model of Energy Efficiency of Hydraulic System

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 275 - 281

Zusammenfassung

Abstract

The article presents the laboratory verification of the mathematical description of losses and energy efficiency of the hydraulic transmission with proportionally controlled cylinder supplied by the constant capacity pump in the system of constant pressure is presented. The axial piston pump with pivoting rotor supplied to the system consisted of proportional directional control valve and linear motor – hydraulic cylinder at constant pressure, cooperating with an overflow valve. The choice of the analysed system is not accidental. There is always a view in literature about the very limited energy capabilities of a proportional control system. For this purpose, measurement methods were developed and a test stand was adapted. It consists of two systems: tested and loading. Measurements during the tests were recorded up to date on the computer hard disk. In order to allow for comparison of the total efficiency of the system with the efficiency derived from the simulation, the ki coefficients determining the energy losses of the individual components were calculated. Investigations have shown a high convergence mathematical description of energy losses in the elements of the system efficiency and reality. This allows accurate simulation determining the energy efficiency of the field at every point in its operation, i.e. at any speed and any load-controlled hydraulic cylinder. The speed and load range of the hydraulic cylinder can also be accurately simulated.

Schlüsselwörter

  • hydraulic systems
  • hydraulic transmission
  • energy efficiency
  • constant capacity pump
  • energy losses
  • mathematical model
Open Access

Experimental and Numerical Investigation of Connector with Elastomer Joint

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 283 - 289

Zusammenfassung

Abstract

This article presents works associated with the design, numerical analyses and experimental tests of an energy-absorbing mat designed for increasing the safety of the soldiers inside military vehicles, especially their legs. One of the most important branches of engineering interests is high technologies accompanying the safety of soldiers. Energy absorbing mats are one of an additional equipment of a military vehicle, which is directly targeted to increase leg safety during explosion of IED (Improvised Explosive Device) under vehicle. The presented invention allows protection legs of the crew’s feet resting on the floor of the vehicle during explosion of a mine or IED. In most solutions, crewmembers’ foot rests directly on the floor, causing serious injuries. The value of the load on the metatarsus and tibia is closely related to the overall vehicle structure, which generally has limitations in the use of available external and internal protection solutions. Energy absorbing mats are a universal solution because they are adaptable to any type of vehicle. Their role is particularly important in flat-bottomed armoured vehicles. The article will show the results of the analysis showing how the mat works. Experimental results will be compared with the results of numerical analysis. The analysis is conducted using the LS-DYNA explicit code.

Schlüsselwörter

  • elastomer
  • energy absorbing
  • LS-DYNA
  • experimental tests
  • FEM analysis
Open Access

Design Modifications of Pressure Boilers with Flat Endplates with Stress Relief Groove

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 309 - 316

Zusammenfassung

Abstract

Stress concentration is still present in the vicinities of structural notches in engineering structures. Zones with higher level of stress are particularly dangerous for structures subjected to fatigue or dynamic loads. The vessels with flat endplates with stress relief grooves are the common examples of such structures. Unfortunately, no clear evidence is given in existing codes how optimally to choose the circular groove radius and the optimal value of that radius depends on the dimensions of the boiler, operating conditions and the material used in manufacturing. Additionally, commonly used grooves with circular shapes are not optimal. Series of experimental tests, numerical or analytical studies presented in numerous articles confirmed these facts. In the presented article, the Authors proposed two-stage modification of the investigated vessel. The first step relies on change of the shape of the groove in the endplate, which provides certain reduction of stress concentration but still plastic deformations in the groove vicinity are not eliminated. The second step of the design modification is proposed for the boiler with the optimal elliptic groove configuration. In this step, some material is added around the top of the outer edge of the endplate. Two simple shapes are proposed for these parts - the short cylindrical ring or alternatively the circular ring welded on the top the endplate is used. For both concepts, the search of optimal dimension/parameters is performed. The numerical results of that study clearly show that the full elimination of plastic deformations near the groove is possible. The numerical analysis and optimizations were made with the well- established finite element software ANSYS, which is accepted by commonly used codes for designing of pressure vessels.

Schlüsselwörter

  • pressure boilers
  • flat ends
  • stress concentration
  • FEM analysis
Open Access

Diagnostics of a Common Rail System Using a Signal Analyser

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 317 - 324

Zusammenfassung

Abstract

Self-ignition engines are currently used to drive lorries, agricultural and road construction machines, as well as passenger cars. Common Rail supply systems are widely used in such engines. Arguments for using these systems include the simple construction of a system as well as practically unlimited control of fuel feeding (division of a fuel dose into several portions), which allows for controlling the fuel combustion process. This facilitates optimisation of the combustion process in limiting toxic emissions, which is the main evaluation criterion for modern combustion engines. Operation of an engine with a Common Rail system is controlled by an Electronic Diesel Control (EDC), which is responsible not only for controlling the supply system, but also for the diagnostics of the whole engine. The diagnostic monitors embedded in the controller supervise the operation of the supply system, but also of the whole engine, including the systems responsible for reducing toxic emissions released to the atmosphere, in accordance with the European On Board Diagnostic (EOBD) standard. Unfortunately, despite sophisticated diagnostic functions, defects sometimes occur in vehicles with engines with a CR system, which are not signalled by EOBD systems. In such cases, an additional tool is needed to help a diagnostician to identify the cause of improper operation of an engine. This article presents several examples to describe the diagnostics of a Common Rail system using an analyser of diagnostic electric signals to detect the cause of such defects.

Schlüsselwörter

  • Common Rail
  • EOBD
  • signals
  • electric
  • signal analyser
  • on-board diagnostics
Open Access

New Gyroplane Hub Connector with Positive Coning Angle

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 325 - 330

Zusammenfassung

Abstract

The article presents advantages and disadvantages of two blade teetering rotors with constructional dihedral angle greater than 0o. Several structural design solutions of rotor hub connector are shown in this work. However, the main attention is focused on innovative hub connector design and manufactured by Trendak Aviation Company during the project “Research and development works on innovative construction of aircrafts of weight over 560 kilograms”. Discusses structural advantages of the new rotor hub connector according to other construction. Also were raised issues related to the load of the gyroplane rotor during the flight, in particular the load of rotor blades root, during a gyroplane break manoeuvre, according to conning angle of rotor hub connector. The disadvantages of using the structural dihedral angle in teetering rotors are also presented, focusing on the rotor aeroelastic instability so-called waving, which from the literature analysed is concerned only with two blades teetering rotors. Performed a coarse analysis in SMOG program, prepared at the Institute of Aviation for the analysis of helicopter and gyroplanes rotors. The stability analysis of the rotor for a number of structural dihedral angle and blades setting pitch was performed. Basis of this analysis the stability boundary were determined for the analysed gyroplane rotor with connector hub with positive coning angle of 2.8o.

Schlüsselwörter

  • blade dihedral angle
  • waving
  • rotor instability
  • teetering rotor
Open Access

Optimizing of Parameters Dipping Metallization of Taguchi Method

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 332 - 337

Zusammenfassung

Abstract

Zinc coatings obtained by immersion metallization are an effective and economical way to protect against corrosion also for high carbon steels, foundry iron alloys. However, the difficulties encountered in surface preparation due to oxide contamination, as well as the presence of carbon (graphite) from the casting process or cast iron sludge, make cast irons zinc-plated by manufacturers reluctantly. The technological properties of the zinc baths and the technological properties of the coatings obtained vary considerably depending on the various impurity and alloying additives. The effect of zincing time significantly affects the thickness of zinc coatings and is dependent on the mass and thickness of the sample. The submerged object heats up faster or slower, depending on the thickness, and its temperature first reaches and then exceeds the melting point of the zinc. However, to avoid zinc over time, it is appropriate to respond to the current ISO standard EN 1461:2009, which specifies the minimum thickness of zinc coatings on steel substrate. The subject of the study was the optimization of parameters metallization using the Taguchi Method. The analysis took into account the influence of the immersion time and temperature of the bath of molten zinc on the thickness of the zinc coating. The test was conducted for three different times, i.e. 30, 60 and 150 seconds and for three different values of the temperature of the bath: 440, 460, 480 [°C]. In order to predict the thickness of the coating, multiple regression analysis was applied, which showed that the experiment was carried out correctly and falling within the limits of tolerance error

Schlüsselwörter

  • metallization
  • galvanizing
  • Taguchi method
  • optimizing
Open Access

Analysis of Wing-Engine Nacelle Aerodynamic Interference

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 339 - 344

Zusammenfassung

Abstract

The article presents an analysis of the wing-engine nacelle flow interference phenomenon on the example of a light twin-engine commuter aircraft. The problems of propulsion system integration with the wing in airplanes are now frequently the subject of advanced optimization research performed by aircraft manufacturers. The shape of the engine nacelle and its connection with the wing determines the quality of the flow around the wing in that area. This is important for high-lift devices placed at the wing trailing edge behind engine nacelle used during the take-off and landing process. Additionally the flow is effected by the disturbances generated by working propellers, the presence of air inlets and an exhaust system of the engine. The article presents a process of numerical optimization of an engine nacelle rear part shape. The main goal of the process was to eliminate the flow disturbances caused by the engine nacelle-wing interference phenomenon. During analysis, the Adjoint Solver method was used to designate nacelle body areas where modification should have the most important impact on the flow quality. The results obtained from adjoint solver were used in the process of finding the optimum shape of the rear part of the nacelle using a parametric geometry generator powered by Ansys Design Modeler and PARADES software. Comparative computational analysis for selected geometries of the engine nacelle was performed using commercial Ansys Fluent solver. Ansys Fluent is an advanced computational solver based on the finite volume method for solving the Navier-Stokes flow equations. Several dozen of geometric shapes were analysed in the optimization process of the nacelle rear part. The final result was the shape of the engine nacelle with correct flow without separation and vortex structures. The article presents results of calculations and visualization of the flow pattern for analysed cases.

Schlüsselwörter

  • air transport
  • nacelle-wing integration
  • flow separation
  • adjoint solver
  • parametric design
41 Artikel
Open Access

The Possibilities and Development of In-Cylinder Catalytic Coating

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 7 - 14

Zusammenfassung

Abstract

Due to the legal changes in the exhaust emission limits in the European Union meeting the new norms becomes more challenging for car manufacturers. The recent progress in the exhaust aftertreatment technology and commercially available aftertreatment systems. However, as the exhaust, systems become more and more complex the problem of high emissions in many engine-operating points that are not currently a part of the type approval tests remains. The article aims to address the limitations of the oxidation catalysts in current aftertreatment systems, mainly their light-off temperature, by investigating new options for in-cylinder catalysts. Placing the catalytic layer within the combustion chamber avoids a number of problems associated with these catalysts being a part of the aftertreatment system. Engine emission tests have been performed comparing the effects of using an in-cylinder Pt-Rh catalytic layer in relation to hydrocarbon and nitrogen oxides emissions. The viable methods of producing a catalytic layer on engine components along with the choice of components to use for catalytic surfaces have also been discussed.

Schlüsselwörter

  • combustion engine
  • in-cylinder catalyst
  • exhaust emissions
Open Access

Engine Fuel Characterisation Through Ultraviolet Absorption Spectra

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 15 - 19

Zusammenfassung

Abstract

In the article, light absorption properties of the fuel oil are considered with a view to create basis for establish optical indicator of the type and quality of this kind of crude oil derivative, in this case the Diesel fuel. The organic solvent – n-hexane – was chosen as a solvent to prepare samples of dilutions of Diesel fuel in several oil concentration. Spectrophotometer Aqualog Horiba were applied to record the absorbance spectra in the ultraviolet and visual range of the light (from 240 to 600 nm) for each previously prepared samples. Obtained results allow concluding that the changes of absorbance occur primarily in the wavelength range from 240 nm to 355 nm. Moreover, the absorbance spectra are characterized by the characteristic sharp peak located at 270 nm for excitation wavelength. Spectra of absorbance were converted to spectra of absorption coefficient based on Lambert-Beer law. Due to the independence the absorption coefficient from the fuel concentration, this parameter could be used as a potential indicator to access composition and quality Diesel fuel used in the diesel engine system. Therefore, preliminary tests allow concluding that absorption coefficient for selected wavelength located at 270 nm could be a sensitive indicator for quick access to fuel quality.

Schlüsselwörter

  • fuel
  • spectroscopy
  • absorptivity
  • diesel engine system
Open Access

Idea of Use of Hydraulic Booster in High-Pressure Fuel Pump with Hypocycloid Drive

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 21 - 28

Zusammenfassung

Abstract

Common rail (CR) injection systems have been universally applied in passenger car engines for twenty years. Moreover, they are applied on a wide scale in trucks, machinery and stationary engines. They have many advantages such as very good fuel spraying due to high injection pressure, injection dose distribution to several smaller, or less heat generation compared to traditional systems. At the same time, the use of this type of system involves a number of problems. They are characterized, among other things, by the high cost of manufacturing and the high sensitivity to changes in the quality of the used fuel.

The most important component of the common rail injection system is the high-pressure injection pump. The authors propose a new, alternative pump design with the hypocycloid drive – the article presents the issue of using this type of pump. Further sections describe the design of a pump utilizing a hypocycloid mechanism; demonstrate beneficial functional features and present selected results of the assembly’s dynamic simulation.

The pump is also characterized by the possibility of multiplying the piston’s pitch while maintaining its diameter. It makes it possible to obtain much greater discharge per operating cycle. Taking into account the considerable quantity of fuel transferring by the pump, was also possible to propose an idea of use of hydraulic booster in such pump. In this field, the authors have presented schematic diagram of a pressure booster with a description of its operation.

Schlüsselwörter

  • high-pressure fuel pump
  • hypocycloid drive
  • hydraulic booster
  • common rail
  • simulation
  • combustion engines
Open Access

Research Injection Pressure with the Kistler 4067E Pressure Transmitter on Sulzer Engine 3AL25/30

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 29 - 36

Zusammenfassung

Abstract

Commonly used in the shipbuilding are combustion piston diesel engines that serve as power generators and main propulsion engines. More stringent of environmental regulations, however, require a more detailed understanding of the processes involved in piston engine combustion to reduce emissions to the environment. Also, the main reason for interest in research in the injection system is also the desire to obtain the highest piston engine power at the lowest fuel consumption. The article presents a study of changes in fuel injection pressure, which allows the operator to analyse the thermodynamic processes taking place in the cylinder. The injection pressure measurement allows you to make proper operating, maintenance and even repair decisions on the object under test. The purpose of this article is to investigate the operation of the injection pressure sensor and to compare the pressure curves measured by the Kistler 4067E sensor in various piston engine-operating states and the simulated failures of the SULZER 3AL25/30 diesel engine. The study was conducted on the SULZER 3AL25/30 engine at the Marine Engine Laboratory at the Gdynia Maritime University. Tests carried out with a measuring instrument for sampling are equipped with a Kistler 4067E pressure transducer, a Kistler 4624A amplifier and a Unitest 2008 computer system serviced with a recorder, processing and signal recording. For a thorough analysis, research conducted at different loads and different simulated engine failure.

Schlüsselwörter

  • diesel
  • engine
  • marine engine
  • injection pressure
Open Access

CFD Analysis of Influence of Axial Position of Shaft on Hydrodynamic Lubrication of Slide Conical Bearing

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 37 - 44

Zusammenfassung

Abstract

During the operation of a slide bearing, the position of its shaft or sleeve varies due to many factors, such as vibrations, load changes, changes in the lubricating viscosity. The vibrations or varying load can cause, that the position of the bearing shaft, measured along its axis of rotation, changes. This is particularly important for sliding bearing with conical geometry. Due to the geometry of this kind of bearing, i.e. where the radius of this bearing (of the shaft and sleeve) has not a constant value, as in the case of a journal bearing, it is more difficult to obtain proper values and describe its hydrodynamic lubrication.

This article shows the results of hydrodynamic lubrication of the slide conical bearing, for which the changes in the position of the bearing shaft in the longitudinal direction, i.e. along its axis of rotation, were taken into account. The commercial CFD software, designed for solving general for flow phenomena problems, was used in the simulations. This article shows the results of simulations, assuming that the lubricating oil behaves as a generalized Newtonian fluid. The hydrodynamic pressure distributions, load carrying capacities and friction torques were calculated for the concerned bearing.

The aim of this work is to show how the operating parameters of the slide conical bearing can be influenced, by only changes of the position of the shaft along the axis of its rotation.

Schlüsselwörter

  • hydrodynamic lubrication
  • conical bearing
  • slide bearing
  • radial clearance
  • CFD
Open Access

Influence of Selected Parameters on Micro Gas Turbine Compressor Design

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 45 - 52

Zusammenfassung

Abstract

The design a micro gas turbine engine is a process that requires analysis of a number of parameters. The initial stage requires consideration of more than 40 parameters [3]. The whole analysis can be made with analytical tools. However, these kinds of tools are limited to preliminary designs. After 1D-calculations and the establishment of the first CAD model, it is recommended to identify the sensitivity of the design. With a modern numerical environment such as ANSYS CFX, it is possible to predict a trend that gives the designer a 3D feedback about the initial design behaviour. For presented centrifugal compressor case, the selected parameters are vaneless diffuser space, design angle and number of stator blades. For qualitative evaluation – important results that influence design are mass flow rate, total pressure and isentropic efficiency. These results are important to turbojet engine performance and efficiency. All chosen parameters respond to given criteria. Validation and verification is still required due numerical errors that are included in CFD modelling. The advantage of 3D prediction is the possibility to eliminate gross errors before parts are sent into production.

Schlüsselwörter

  • jet engine
  • gas turbine
  • design
  • trend prediction
  • centrifugal compressor
Open Access

Experimental and Numerical Three-Point Bending Test for Sandwich Beams

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 53 - 62

Zusammenfassung

Abstract

The article deals with an experimental investigation of mechanical properties of sandwich beams obtained from bending tests. The tested specimens consisted of foam or honeycomb core and face sheets made of aluminium alloys, plywood or composite material. The face sheets and the core were bonded with glue material. Beams of different dimensions, namely beam width, as well as core and face sheets thickness, were tested. Three point bending tests were carried out, which mid span deflections of the beam versus applied force were recorded. Experimental test results were compared with simulations on the basis of finite element method. The full, non-linear analysis, taking into account large displacements and using contact elements was performed. The obtained results are presented in load-deflection diagrams. Some conclusions concerning ultimate loads and failure behaviour of tested beams made of different materials have been derived.

Schlüsselwörter

  • numerical simulation
  • bending tests
  • composite materials
  • sandwich beams
  • honeycomb
Open Access

The Burnishing Process of the Stainless Steel in Aspect of the Reduction Roughness and Surface Hardening

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 63 - 69

Zusammenfassung

Abstract

In the article were presented influence of technological parameters of burnishing process on the degree of hardness and reduction roughness. Burnishing process carried out for stainless steels X2CrNiMo17-12-2. The experimental research were obtained in the surface layer increase in hardness and the material ratio curve a convex shaped, which, taking into account the load capacity of the surface will be directly affected by its resistance to wear and corrosion. The experimental research by application of the burnishing rolling – pressuring process (BRP) method were made in the Laboratory of Production Engineering at the Department of Marine Maintenance at the Faculty of Marine Engineering at the Gdynia Maritime University. After the studies it was found that the hardness of the surface layer and the roughness of the shaft necks an important influenced by technological parameters of processing (burnishing speed, feed and depth of burnishing). The objective of applying burnishing process may be, for example, the need to increase surface smoothness and dimensional accuracy of part. To achieve the objectives strengthen and smooth of burnishing stainless steel should be used the one pass burnisher roller and feed fn = 0.2 mm/rev and disk burnishing tool feed an = 1.0 mm and burnishing speed vn = 70 m/min.

Schlüsselwörter

  • burnishing rolling – pressuring process (BRP)
  • surface roughness reduction ratio
  • degree of relative strain hardening
  • stainless steel
Open Access

Model Testing of the Internal Leaks of Valve Body in Automatic Transmission

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 71 - 78

Zusammenfassung

Abstract

The article presents the working conditions and the functions of the ATF fluid in an automatic transmission. It was noted that the correct operation of the automatic transmission is heavily influenced by the quality of the ATF fluid, which operates in disadvantageous conditions of oxidising environment, is subject to contamination and undergoes intense shearing, thus changing its physical and chemical properties during use. The analysis included the disadvantageous, from the point of view of loss of fluid pressure in the automatic transmission’s hydraulic system, phenomenon of the fluid’s flow through fractures (clearances) of the hydraulic precise pairs “called the rate of flow through internal leaks” or an “internal leak”. The model of the rate of flow through internal leaks was proposed to determine the impact of the precise pairs’ wear and the hydraulic fluid’s properties on the aggregated leaks in the hydraulic system controller of the automatic transmission. The modelling utilised the dependency between the rate of flow through internal leaks of the hydraulic precise pair and the coaxial circular fracture. The model’s assumptions were formulated. The values of clearances of the electrohydraulic controller’s precise pairs were determined during the measurements of the actual structure – based on the automatic transmission’s mileage. The measurements featured relevant diameters of pushers and sliders, as well as internal diameters of cylindrical openings of manifold sliders and hydraulic suppressors. Variant model testing was conducted with various degrees of the fluid’s wear and temperature (viscosity and density) for conditions of driving with transmission “1” and “2”.

Schlüsselwörter

  • automatic transmission
  • hydraulic system
  • hydraulic precise pair
  • wear of hydraulic couplings
  • internal leaks
  • ATF fluid flow rate model
Open Access

Ecological and Economic Conditions for Implementing Hydrogen Fuel

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 79 - 86

Zusammenfassung

Abstract

Hydrogenation of the motor transport has become the highest form of broadly understood contemporary electro mobility, with the use of hybrid vehicles through fully electrical vehicles to fuel cell vehicles. This article presents development of hydrogen technology applying fuel cells, in particular in road transport.

The emission of greenhouse gases in the production cycles of the said fuel were discussed, depending on the use of various energy carriers in its production. Emphasis was given to the rationale underlying the production of hydrogen for the needs of fuel cells. Furthermore, the advantages were presented of exploiting electrical power for the production of hydrogen with the use of renewable sources of energy. The example of France was used to discuss the advantages of the hydrogen fuel technology for reducing the emission of combustion pollutants, in particular the emission of carbon dioxide.

The article also evaluates – on the example of Poland – average unit costs (PLN/km) for using fuel cell vehicles. At present, they will be higher than in case of vehicles with conventional drivers. High cost is one of the causes – apart from limited production of fuel cell vehicles – of slacked development of the hydrogen fuel technology. The article also presents premises for the road transport hydrogenation national plan in Poland.

Schlüsselwörter

  • road transport
  • hydrogenation
  • ecological
  • economic conditions
Open Access

Nitrogen Oxides Emission Estimator for a Diesel Engine Use to Reduce the Emission of Harmful Substances in Exhaust Gas to Environment

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 87 - 94

Zusammenfassung

Abstract

This article reports the results of experimental and numerical analysis of emissions of nitrogen oxides in exhaust gas to the environment from a turbocharged diesel engine of a tractor. The problem of identifying nitrogen oxides emissions from the exhaust gases was formulated and subsequently solved, based on data gained from measurements. The results of estimation of nitrogen oxides emissions were verified on the basis of research on a test object. The object of the study and a non-linear static model of nitrogen oxides emission were also described for two systems – with and without exhaust gas recirculation. The article demonstrates that the use of an adequately selected mathematical model can lead to the estimation of emissions of nitrogen oxides contained in the exhaust gas of diesel engines in an off-road vehicle. The created model can be used to control the valve of the exhaust gas of recirculation system and so reduce the emission of harmful substances to the environment. The presented research results show the comparison of estimated and measured nitrogen oxides concentration. The estimated value from the mathematical model concentration is about from 0.7 s to 1 s earlier than the value measured by the sensor, therefore the exhaust gas recirculation system could be controlled accordingly before nitrogen oxides are formed.

Schlüsselwörter

  • nitrogen oxides emission
  • diesel engine
  • estimation
  • combustion engines
  • air pollution
  • environmental protection
Open Access

Utilization Possibility of Marine Trent 30 Gas Turbine as Prime Mover on Vessels

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 95 - 100

Zusammenfassung

Abstract

Gas turbines are used as marine prime movers but the market is dominated by the diesel engines (of course turbocharged but they are still diesels). The share of gas turbines is on a level of 4-5% in the worldwide shipping.

It was presented the chosen parameters of Rolls-Royce gas turbine MT30 with nominal power 36 MW or 40 MW prepared for marine utilization. It is a good example of development of marine gas turbines with the trial to eliminate the effect of ambient temperature especially on turbine load.

It was discussed the significance presented data for possibility of utilization on vessels. It was indicated the advantages and disadvantages of gas turbine sharing.

It was mentioned the installation problems: pressure drop in inlet and outlet ducts on the accessible turbine power and specific fuel consumption.

It was discussed what important parameters ought to be known for safe turbine operation and maintenance. There is a little information lack. The gas turbine ought not to be treat as a black box. In the end, some final remarks are presented.

Schlüsselwörter

  • marine prime mover
  • gas turbine
  • propulsion
  • gas-electric plant
  • gas turbine utilization
Open Access

Automated Guided Vehicles – The Survey

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 102 - 110

Zusammenfassung

Abstract

Transport has always been a fundamental impulse for the development of civilization. The first fully automatically controlled vehicles for industrial application (previously called driverless vehicles) was design in 1954 year. This has been achieved more than 60 years ago. Unmanned Ground Vehicles are a whole family of autonomous vehicles use modern tools with all power today available electronics for navigation task and decision making process on the base artificial intelligence and (AI) algorithms. At present time a problem of the realization a fully reconfiguration navigation system working in real time mode for UGV vehicles is the subject of the research for many scientific units of the entire scientific world. The object of the statement constitute AGV short historical outline with actual trends marking. The special authors’ attention was focused on the solutions dedicated for so-called e-tools functionalities implementing in modern AGV vehicles. The main purpose of the article was focused on the set of issues involving the most problems in the whole material handling (MHD) family devices with any autonomous factor. The article is focused on the localization problem, trajectories founding, path planning, scheduling, workspace with environment mapping and AGV control issues. Described methods and tools are connected with chosen artificial intelligence solutions dedicated or adapted for autonomous vehicles’ needs.

Schlüsselwörter

  • AGV
  • navigation
  • patch planning
  • scheduling
  • workspace mapping
  • control
  • telematics
Open Access

Mathematical System Model for Acoustics Based Telematic Micro Services in Iot for Transportation Setting

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 111 - 118

Zusammenfassung

Abstract

Despite the wide adoption of Internet of things (IoT) with several webs standards and cloud technologies, building of city wide IoT based smart city platform for solving transportation problem remains a daunting task. Owing to the dynamic nature of IoT and components of transportation systems, smart city architecture would require development of a scalable, distributed and evolving architecture on the web. With the advancement in autonomous transportation system there is a need for in adaptive telematic system for communicating with other vehicles, sensor nodes etc. As transport, services have special requirements of which are related to the size and type of information to be exchanged between vehicles (vehicle-to-vehicle communication) and the control centre. . By the time the data makes its way to the cloud for analysis, the opportunity to act on it might be gone. Thus handling such huge streams of data on the fly is a daunting task. In the study we present an interoperable swarm, logic based mobile terminals running multimedia micro services based telematic system.

Schlüsselwörter

  • Telematic micro services
  • Acoustics based Internet of Things
  • Telematic
  • Smart City
Open Access

Structure of Transport Model on Strategic Level of Management for Assessment of its Configuration

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 119 - 126

Zusammenfassung

Abstract

The aim of the article is to present the issues related to the use of the transport model for ex-ante evaluation of the functional and operational configuration of ITS. Variants of ITS configuration have been presented based with use of ITS user needs from FRAME methodology and with use of ITS user services implemented in cities of Poland. The structure of the transport model on strategic level of traffic management has been presented in the context of the following impact of ITS configuration: changes in the use of paths in network, changes in the use of transport system modes, changes in the destinations of trips, and changes in the number of trips for various purposes. The results of transport model enable a comparison, using an incremental method, results of transport decisions of users, obtained in specified forecast horizons for the ITS variants of configuration. Structure of transport model presented in article is suitable for strategic level of traffic management with long-term results. While transport models for tactical level of traffic management with medium-term results, and for operational level of traffic management with short-term results are used to determine the characteristics, describing traffic conditions in a transport network, for example expected smoothness of traffic flows, and to determine dynamic characteristics describing for example information spread processes in dynamic traffic networks.

Schlüsselwörter

  • ITS configuration
  • intelligent transport systems
  • transport model
  • ITS user services
  • ITS configuration
Open Access

Maritime Radio Information Systems

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 127 - 134

Zusammenfassung

Abstract

The article presents and evaluates the technical and operational possibilities of the maritime radio communications systems to be used especially for the exchange of information between the land users and ships. The basic functional requirements and regulations for Global Maritime Distress and Safety System (GMDSS) referring to the maritime radio information systems, resulting from the provisions of the International Convention for the Safety of Life at Sea (SOLAS) and Radio Regulations have been described. The article presents the role of information systems in the shipping and GMDSS as well. A current status of the maritime radio communication systems responsible for the exchange of information between the land users and ships has been presented. Operational and technical characteristics of the maritime radio systems used for the exchange of safety information and ships’ operating information have been described. The analysis of the systems responsible for broadcasting to the vessels the Maritime Safety Information (MSI) has been made. In this context, the operation, methods and ranges of broadcast of the Maritime Safety Information by the NAVTEX system and Inmarsat SafetyNet system have been discussed. The analysis of the systems responsible for the ships’ operating communications has been made too. The article also outlines the future of maritime radio information systems. In this context, two projects currently being implemented in the framework of the International Maritime Organization (IMO) by the Sub-Committee on Navigation, Communications, Search, and Rescue (NCSR) have been presented. The first of these projects under the name of e-Navigation refers to the use of the latest information and communication technologies in shipping. The second one concerns the modernization of the GMDSS. It is expected that as the outcome of these project works, among others, new maritime radio information systems presented here will be adopted.

Schlüsselwörter

  • communication systems
  • maritime safety communication
  • ships’ operating communication
Open Access

Experimental Testing of the Vehicle Heating System

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 135 - 141

Zusammenfassung

Abstract

An important problem in the design of machinery and equipment at the stage of determining their structure is the issue of providing adequate thermal comfort to users while operating in variable climatic and environmental conditions. This issue is of particular importance because all types of machinery and devices are equipped with very expensive and automated control and monitoring system, which should guarantee adequate warming conditions and should work under different climatic conditions. Examples of these tendencies are special solutions for vibroacoustic insulation of the inside of the devices, special air conditioning equipment, special constructions, ergonomic inside solutions. The process of shaping the discussed structural design of vehicles in terms of meeting the relevant technical and operational criteria is currently being increasingly realized through experimental tests of prototypes supported by numerical calculations. The purpose of this paper is to present the methodology of conducting test stand as a stage for the experimental determination and verification of temperature distribution, the location of heating and air conditioning devices in a prototype vehicle in variable climatic conditions (minus 15ºC). The research was carried out in a large-scale climate chamber. It covered the process of heating up the passenger area of the bus and the time of temperature stabilization on the inside of the vehicle while operating the heating systems. An additional attempt was made to test the heating system while the vehicle was in motion and to open the vehicle door to simulate the stopping of the vehicle at the bus stop. Another aspect that was analysed was the impact of the installed convector on the vehicle when the liquid heater was off.

Schlüsselwörter

  • heating system
  • temperature distribution
  • temperature tests
  • thermal chamber
Open Access

Ecological Indicators of the Perkins 1104D-E44TA Engine After Its Adaptation for Being Powered with Natural Gas and Diesel Fuel

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 143 - 150

Zusammenfassung

Abstract

The contemporary progress of automotive industry and transportation is determined to a large extent by the increasing environmental requirements, aimed at limiting the harmful impact of vehicles upon human life and people’s health. A crucial issue linked with operating vehicles is the exhaust gases generated by internal combustion engines. In order to reduce this hazardous impact upon the natural environment, the construction of the engines is continuously improved, electronic controlling is being developed for managing the course of working processes taking place in cylinders and auxiliary systems, exhaust gases cleaning systems are being developed, alternative fuels are being sought for and the possibilities of their optimal use are being examined. Natural gas is the fuel that is highly expected and hoped to be used more widely for powering internal combustion engines in vehicles. This article presents the values of selected ecological indicators of the Perkins 1104D-E44TA Diesel engine, powered by compressed natural gas and Diesel fuel (CNG + ON). For comparison reasons, the engine was powered with both fuels at the same time and then only by Diesel fuel (ON) in the same working conditions. Before the tests, the powering system control unit had been calibrated so as to enable obtaining similar values of torque while the engine was powered with the Diesel fuel only and with both CNG and ON while working with external speed characteristics; the calibration was also set up to allow for the maximum share of the natural gas in the total fuel amount supplied into the engine cylinders without engine knocking. When powering the engine with both CNG and Diesel fuel, the concentration levels of nitric oxides and carbon dioxide in exhaust gases were lower. However, the total content of hydrocarbons in the exhaust gases grew multiple times, and the content of the carbon monoxide was significantly increased. In addition, the obtained measurement results of the smokiness of the exhaust gases and the content of the soot with the engine powered with two fuels were not satisfactory.

Schlüsselwörter

  • piston combustion engines
  • engine fuels
  • harmful exhaust gases components
  • bi-fuelling
  • natural gas
  • experimental tests
Open Access

Validation of Selected Presented Method Measured of Length Fatigue Gap on Compressor Blades Forming During Resonant Tests

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 152 - 158

Zusammenfassung

Abstract

In this work, the validation of selected presented method measured of length fatigue gap was shown. The article describes three methods of determining fatigue gaps. The object of the study was the first stage compressor blade from aircraft engine. Blades have defects on the leading edge. This defect on the blade (as a result of the resonance vibration) was the origin point of the fatigue gap. Two of the methods, fluorescent and thermovision, were optical. The fluorescent method was a direct measurement, whereas direct-indirect thermography. The last of the presented methods was an analytical method, showing an algorithm based on amplitude-frequency characteristics. The advantages and disadvantages of these methods were compared. As a result of the analysis performed by the algorithm, there were specified patterns defining the dependence of change in crack length depending on the asymmetry of AF characteristics. The accuracy of the following methods and the results obtained for chord length were determined. Thanks to such use, these results have a utilitarian meaning. Such a compilation allowed us to evaluate the usefulness of particular measurement methods. Proposed methods of measuring the length of fatigue crack are used in experimental studies. It is also possible to implement them for research conducted during the operation of an aircraft engine.

Schlüsselwörter

  • crack propagation
  • gap
  • thermovision
  • turbine engine
  • blades
Open Access

Description of Strength of Wood Composite in Compound State of Load

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 159 - 165

Zusammenfassung

Abstract

All constructions are subject to the most compound loads and therefore a suitable effort hypothesis should be used for their calculation. For anisotropic materials, a hypothesis should be used to describe the properties of such materials. In the work have been shown the strength of the layers composite on the example of construction wood in a compound stress state. Wood composite is an orthotropic material. Wood is composed of alternating layers of soft wood and hard wood. Single layers are monotropic material. The use of a stress hypothesis, which describes the strength of an orthotropic material, requires will make an investigation. Studies is purposed to determine the tensile strength along and across the fibres. The compressive strengths along and across the fibres and the shear strength. Particularly the determination of shear strength requires special tooling so that in the case of flat samples in the measuring part it is possible to determine the shear stresses. Therefore, a research stand was designed and constructed. Known stress hypotheses for anisotropic materials have been analysed. The analysis showed that the strength of the wood composite could be described by the Tai-Wu stress hypothesis. Based on the results of the research, numerical calculations were performed. Calculations allowed determining the distribution of stresses in the sample measuring part. The results tests and numerical calculations have shown that obtaining a homogeneous stress (shear) condition for anisotropic materials is very difficult. Wood belongs to materials whose mechanical properties depend on many parameters, so the description of the effort of this material is a compound issue. Studies have shown that wood reinforcement by polymer saturation is best suited to the compressed loaded structures.

Schlüsselwörter

  • compound state of stress
  • modified wood
  • effort criterion
  • strengthening of the material
Open Access

The Economic Dimension of the Electromagnetic Process – Comparison Study of Costs of Repairs of Electric Vehicles and Powered with Conventional Fuels

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 167 - 172

Zusammenfassung

Abstract

The development of electro-mobility in Poland is one of the inevitable processes awaiting the Polish automotive industry. For each potential electric vehicle user, the information on the vehicle’s operating costs therefore becomes an imperative of tremendous importance. The analysis of market prices of passenger cars clearly indicates that the costs of acquiring a new electric vehicle are much higher than conventional fuel vehicles. Therefore, the expectations of customers themselves become fundamentally significant, who in relation to the spare parts in the case of this category of vehicles expect the highest technological and quality standards while maintaining the suitable price parameter.

The article attempts to signal the issues related to the evaluation of electro-mobility parameters by presenting the comparative study of the costs of repairing electric vehicles and vehicles fuelled by conventional fuels. Considerations were supplemented by authoritative cost simulations, including the comparison of the same models of vehicles equipped with both the conventional and ecological power units. The aim of the article is to draw attention to the essence of the research problem and to answer the question whether the total costs of operating electric vehicles are in reality significantly lower than that of vehicles fuelled by conventional fuel.

Schlüsselwörter

  • electro-mobility
  • alternative power sources
  • conventional fuels
  • operating costs
  • economic dimension
  • repair costs
  • spare parts
Open Access

Analysis of General Aviation Domestic Air Traffic Structure in Controlled Airspace of Poland with Refer to Sesar 2020, PJ.06-02 Project Solution

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 173 - 180

Zusammenfassung

Abstract

Civil air traffic in Poland is organized in accordance with international regulations provided by International Civil Aviation Organization (ICAO). Flight operations are performed in controlled airspace (CAS) or uncontrolled airspace. The division contains different approach to flight planning (FP) and group specific types of airspace users (AUs) and aircrafts types. Typically, General Aviation (GA) operations are placed in uncontrolled airspace while airline operations in CAS. This practice results from air operations types and aircrafts flight performance. GA includes sport, school, private transport or business flights and therefore the uncontrolled airspace with its vertical border form the ground to FL 95 contains most of the GA operations. However, there is a part of GA operations performed in CAS according to Instrument Flight Rules (IFR). The aim of the work is to describe the structure of domestic GA operations in IFR flights in CAS of Poland. Using the archival air traffic data from previous five years (2012-2016) the defined subject was analysed. In the first part, the aircraft fleet is presented. It contains the description of aircrafts types with relation to route distances, number of flights, propulsion type and wake turbulence category (WTC). In the second part, the network of defined air traffic was shown. It contains data about departure and destinations airports, the airports loading, month statistic of flights and trend in traffic changes. The traffic data are obtained from Eurocontrol database Demand Data Repository (DDR2) and using the NEST Eurocontrol software. The article arose during author’s traineeship in Eurocontrol within a framework of SESAR 2020 project, PJ.06-02 solution. Presented analyses are useful from the FP point of view since the PJ.06-02 solution refers to “Management of Performance Based Free Routing in lower Airspace” and need to consider the features of every airspace users.

Schlüsselwörter

  • general aviation
  • controlled air traffic
  • SESAR 2020
  • IFR flights
  • domestic flights in Poland
Open Access

Mathematical and Graphical Modelling of Aerobatic Flight Trajectories

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 181 - 187

Zusammenfassung

Abstract

The article presents the current state of knowledge related to mathematical and graphical modelling of aircraft trajectories, particularly those of aerobatic flights. The first part of the article is an introduction to the subject of training and aerobatic flight. In the second chapter of this work, the authors describe the basic definitions related to mathematical modelling, rules for glider aerobatics (rules for the pilots and for the judges) and specification of navigation software, which is using during competitions. In the further part of the article the authors present example possibilities of application of the mathematical modelling tools in General Aviation and describe the possibilities of implementing the obtained models in selected navigation and tracking systems. In the same part of the article there is a description of the AeroSafetyShow Demonstrator PL – an intelligent system of flights supervision and safety (ASSD+PL), which will be using to compare the real flights trajectory and the models build trough the mathematical software. ASSD+PL in also only tracking system using by the judges at glider aerobatic World Championships. The aim of this article is to validate the applicability of the system comparing to the actual aircraft trajectory with the models referred to as ‘ideal’ for aerobatic purposes.

Schlüsselwörter

  • mathematical models
  • flight trajectory
  • aerobatics
  • flight safety
  • glider aerobatics
Open Access

Selected Problems of Real Driving Emissions Measurement

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 189 - 196

Zusammenfassung

Abstract

The article compares driving test data using the latest legislative proposals applicable to passenger cars. Real Driving Emissions procedures have been introduced in the Commission Regulation (EU) 2016/427. Currently, quantitative RDE requirements have been established to limit emissions from exhaust systems in all operating conditions in accordance with the road emission limits set out in Regulation (EC) No. 715/2007. Several measurements were performed on the same test route in accordance with the RDE test guidelines, which requires a number of criteria to be met. These criteria include the length of the measuring segments, their overall test timeshare, and the dynamic characteristics of the drive. A mobile device for reading the EOBD System information was used to record the engine and vehicle operating parameters during tests. This allowed for the monitoring of parameters such as: load value, engine speed and vehicle velocity. The obtained results were then analysed for their compatibility with the RDE procedure requirements. Despite the same research route, the obtained results were not the same. The analysis also uses the two-dimensional operating time-share characteristics expressed in vehicle velocity and acceleration co-ordinates. As a result, it was possible to compare the dynamic properties, share of operating time and, consequently, to check the validity of conducted drive tests in terms of their practicability and emission values.

Schlüsselwörter

  • exhaust emissions
  • road test
  • real driving emissions
  • environmental protection
Open Access

The Environmental and Social Costs of the Intermodal Transport of Semi-Trailers By Rail

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 197 - 201

Zusammenfassung

Abstract

The dynamic development of transport recorded in recent decades is an important factor in the economic development of the world on the one hand, and on the other hand, it is a significant source of nuisance and environmental problems. The adverse impact of transport can be felt both in the natural environment and in society, where the dynamic development of this sector has enabled significant civilization development, with the effects varying depending on the level of economic development, the degree of advancement and use of the various transport sectors, geographical location (including climate), and also the sensitivity of the elements of the environment. Considering contemporary transport hazards, it is important to prevent them from occurring, and when that is not possible – limiting their impact on the environment and reducing the scale and extent of negative impacts.

In the article, the environmental and social nuisance of transport of goods loaded in semitrailers was analysed. The transport of semitrailers using intermodal wagons pulled by the diesel locomotive in accordance with the assumptions adopted in the railway with the maximum length of train composition was taken into account.

Schlüsselwörter

  • railway
  • intermodal transport
  • semi-trailer
  • environmental costs
  • social costs
Open Access

Carrying Capacity and Friction Forces in a Transverse Journal Bearing, Lubricated with Non-Newtonian Oil

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 203 - 210

Zusammenfassung

Abstract

In this article, the authors present the results of numerical calculations. Calculations concern dimensionless carrying capacity and friction forces in a transverse journal bearing, lubricated by the oil of non-Newtonian properties. For analytical-numerical considerations a model of apparent viscosity changes based on exploitation time, pressure, temperature, shear rate was assumed The non-Newtonian properties of lubricating oil were characterized by increasing viscosity with increasing shear rate and described as an additional part in the constitutive equationβ3·tr(A12)A1.

Analytical-numerical calculations were performed for smooth, non-porous plain bearing with full angle of wrap. Non-isothermal, laminar and fixed flow of lubricant in the lubrication gap of the journal bearing was assumed. Numerical calculations of hydrodynamic pressure distribution were made for Reynolds boundary conditions. The finite difference method was used to determine the Reynolds equation and the successive approximation method by taking into account the influence of pressure, temperature and non-Newtonian properties on the change of apparent viscosity. The results of the calculations are presented in the form of graphs and tables illustrating the influence of relative eccentricity and pressure, temperature and non-Newtonian properties on changes in the dimensionless load and friction force. Analysis of the obtained results illustrates the high-pressure effect on the increase of the carrying capacity and friction force for high relative eccentricities. A similar situation is by considering the non-Newtonian properties.

Schlüsselwörter

  • slide journal bearing
  • hydrodynamic pressure
  • load carrying capacity
  • friction force
  • non-Newtonian oil
Open Access

Model of Vehicle Electric Drive System

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 211 - 220

Zusammenfassung

Abstract

Models of electrical energy storage devices – a battery and a supercapacitor – as well as models of motor and a control system, were used to feature the work of a hybrid electric drive system. The models were adapted to simulate driving with a given driving cycle, in a quasi-static method, with the use of MATLAB-Simulink software. The advantage of this method is that calculations can be done quickly and results can be easily compared.

A battery model enables determining voltage and charge level in relation to load current and temperature. The basic parameter of a battery is a nominal capacity. It is a measure of energy stored in the battery, which can be absorbed within discharge time, in conditions of temperature and current. The energy can be absorbed until the minimal voltage is reached in the clips. The article presents simulation of calculations lead that the described electric drive model. The model makes it possible to analyse different concepts of steering the whole system already in the initial phase. In particular, the article presents PMSM model and trajectories of selected parameters during a trapezoidal driving cycle.

Schlüsselwörter

  • transport
  • electric vehicle
  • energy storage
  • electric drive
  • driving cycle
  • battery model
Open Access

Intensity of Motor Trucks Operation Versus Vehicles’ Age, in Several Categories of Engine Cubic Capacity

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 221 - 228

Zusammenfassung

Abstract

Changes in the vehicle operation process, which take place with vehicle’s age, have been analysed on the grounds of data collected for over 3 000 motor trucks of more than 3 500 kg gross vehicle mass (GVM), being now in use in Poland. The analysis has covered a 20-year vehicle operation period (referred to as “service life planned”); the distance travelled by a vehicle during this period has been called “target mileage” (expressed in kilometres). As a measure of the intensity of vehicle operation, the “monthly mileage” has been adopted. The monthly mileage values specified in the article strongly depend on the category of engine cubic capacity. Some important characteristics of the mileage growth process, noticed in the recent years along with an intensive development of the road transport, have been presented. The vehicle mileage growth process has been shown for four categories of engine cubic capacity, on the grounds of regression lines based on a polynomial model.

The vehicles with engines of more than 10 000 cm3 capacity reach more than 1/3 (i.e. 34.7-36.6%) of their target mileage for the first 60 months of operation, while covering only 2-5.3% of this target mileage during the last two years of their 20-year service life planned. During the first 5 years, the intensity of operation of vehicles belonging to this engine capacity category is four to five times as high as that determined for the last 5 years of the 20-year vehicle operation period under analysis. Calculations carried out have shown that the dataset under analysis includes vehicle categories where 90% of the target mileage is reached as early as after 69-70% of the service life planned. This shows that motor vehicles having been used for a short time predominate in the road transport of goods in Poland and that there is an interrelation between the rates of changes in the vehicle operation intensity and the engine capacity.

Schlüsselwörter

  • motor vehicle operation management
  • motor truck mileage
  • intensity of vehicle operation
Open Access

Control of Fiat Multiair Valve-Lift System Using Atmega Microcontroller

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 229 - 236

Zusammenfassung

Abstract

The article presents a device based on the ATmega microcontroller for precise Fiat MultiAir valve-lift system control. The Fiat MultiAir system is the patented electromechanical actuation system of the inlet valves. It allows a control of the inlet valves open time for each combustion chamber independently. The described device has been installed in the Fiat 0.9 TwinAir CNG 80 HP internal combustion engine controlled by the ECU Master open motor controller. As the ECU Master Controller software and hardware does not support Fiat’s MultiAir system control, the above-mentioned device had to be designed. The device consists of the ATmega88 microcontroller, which analyses the signals from the shaft and the cam sensors. Then, the DC converter is powering the solenoid valves of the MultiAir system via two transistors. When the solenoid valve is closed, the incompressible hydraulic fluid transmits the inlet-cam lobe’s motion to the valve as in a traditional engine. When the solenoid valve is open, the oil bypasses the passage, decoupling the valve, which then closes conventionally via spring pressure. In order to find the specific moments of turning the solenoids on and off the measurements on the original Fiat motor controller have been performed. The acquired oscillograms have been analysed and presented in the article. Studied Fiat 0.9 TwinAir engine is a part of the power generation unit and has been coupled with the three-phase electric power generator MeccAlte 16 kW with an AC exciter.

Schlüsselwörter

  • Fiat MultiAir system
  • valve-lift system
  • variable valve timing
  • open motor controller
Open Access

Aerodynamic Interference Between Pusher Propeller Slipstream and an Airframe – Literature Review

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 237 - 244

Zusammenfassung

Abstract

In the article, an aerodynamic interference between pusher propeller slipstream and the airframe of the aircraft powered by it has been presented, based on a literature study. A pusher propeller is one of popular types of the airplane propulsion. It is applied mainly in light sport aircrafts, in the UAVs (Unmanned Aerial Vehicles), unorthodox vehicles, like compound helicopters, canard and joined wing aircrafts etc. The main advantage of pusher propeller is that the engine with the pusher propeller does not affect the visibility from the cockpit and allows placing an electronic equipment in the front part of the UAV’s fuselage. Furthermore, reduced cabin noise and increase in stability due to acting normal force aft of the centre of gravity are other benefits of this configuration. The pusher propeller impact on the airframe, especially on the wing, is qualitatively different from the tractor configuration. Main differences between both propulsions has been discussed, as well as aerodynamic benefits of the pusher propeller – like reduction of separated flow area and extending area of laminar boundary layer. However, an application of pusher propeller may have also negative impact, especially lower performance than tractor propeller. In the article the reasons of this suppression has been briefly discussed.

Schlüsselwörter

  • air transport
  • air propulsion
  • pusher propeller
Open Access

Experimental Research on Identifying Data for Modelling Special Purpose Vehicles

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 245 - 252

Zusammenfassung

Abstract

The work presents selected results of experimental research on special purpose vehicles used on military training grounds, and bench tests of their main structural elements. The results are connected mainly with identifying the main vibration parameters of those vehicles (regarding weight, resilience and damping), and with the assessment of the level of dynamic loads. The more output data experimental research provides, the more input data we have for designing models. Determined in laboratory tests, weight parameters (regarding weight and moments of inertia), coefficients of stiffness and damping, as well as selected resilience and damping characteristics, are applied in the process of creating the numerical models of assemblies, systems, and complete vehicles. The numerical models created are subject to full verification in order to minimize the differences between the real objects and their representations. The models are applied in multivariate simulation tests of the existing design solutions, upgrading them, or creating new designs. Due to a certain sensitivity of the range of special purpose vehicles, the results of experimental tests and simulation analyses presented in the work are mainly qualitative rather than quantitative.

Schlüsselwörter

  • special purpose vehicle
  • combat vehicle
  • loads
  • experimental research
  • modelling
Open Access

Security of Telecommunications Systems in Transport

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 253 - 260

Zusammenfassung

Abstract

The article presents the selected elements affecting reliability and security of the telecommunications networks, which support transport services. In terms of telecommunications security, the selected methods and mechanisms, which allow providing the required level of reliability and availability of the telecommunications networks, in the fault-free operation and emergency modes, were discussed. In the article, attention was paid to the impact of a way of operation and maintenance on security of the telecommunications networks, and also on a correlation between the telecommunications system security and the security culture within the administrative and decision-making bodies.

The telecommunications networks used in transport ensure the broadly understood safe provision of data transmission services. Telecommunications networks consist of hardware and software systems, and the data transmission security depends both on hardware and software. It is a set of methods and mechanisms, which provides a high level of the system’s reliability and availability by selecting the appropriate system structure.

Schlüsselwörter

  • security
  • transport
  • telecommunications
  • reliability
  • availability
Open Access

A Novel Device with Variable Friction for Shock and Vibration Control

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 261 - 268

Zusammenfassung

Abstract

In this article a passive system, which exploits the properties of the Coulomb friction and leads to high affordability of controlling shocks and vibrations by means of cheap devices is presented. The friction force developed by the proposed device is dependent on the motion stroke by convenient modulation of contact force between the elements of friction coupling. For providing the system self-centring properties or necessary vertical load capacity, coil springs can be incorporated into the device structure. The device hysteresis characteristic can be simply adjusted to comply with requirements of the considered application. A general mathematical model of device dynamic behaviour is developed and applied to shock and vibration isolation systems.

The article presents a novel passive device with variable friction which hysteresis force-displacement characteristics have “butterfly” shape, achieved by appropriate design of friction coupling. This shape of hysteresis loops can mitigate the drawbacks of constant friction devices. The schematic of mechanical systems to analyse the dynamic behaviour of shock and vibration isolation systems with variable friction device are shown.

Schlüsselwörter

  • variable friction
  • hysteresis
  • shock and vibration isolation
  • simulation
Open Access

Water Emulsions of Hydrocarbons as Diesel Engines Fuel

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 269 - 274

Zusammenfassung

Abstract

Testing of internal combustion engine engines with hydrocarbon emulsions with water has its tradition. Previous attempts have been made using emulsions obtained chemically. This article presents similar results with the fact that emulsions of water and fuel were obtained using the cavitation phenomenon. The studies included standardized tests and non-standard measurements of polycyclic aromatic hydrocarbons (PAHs) emissions. The author, at the Wroclaw University of Science and Technology (Department of Vehicle Engineering) has developed a specific cavitator, which has been used to make emulsions of mineral and synthetic hydrocarbons. Both fuels (mineral and synthetic hydrocarbons) and their emulsions, with a water content of twenty percent (by volume), were used for testing. The engine ESC test conditions were developed. The engine was tested under the conditions of this test. Emissions of exhaust gas components (including polycyclic aromatic hydrocarbons) and fuel consumption were determined. It has been found that the use of emulsions leads to a reduction in the consumption of hydrocarbons. It has also been found that the engine power emulsion leads to a significant reduction in the emission of carcinogenic aromatic hydrocarbons, the highest concentrations of which in the exhaust gas are determined when the engine is powered by mineral diesel. Concentrations of other, considered “neutral”, polycyclic aromatic hydrocarbons changed with respect to some as they rose, others diminished, and others remained at a constant level. The “neutrality” of these hydrocarbons is due to the fact that the effects on living organisms were evaluated for each hydrocarbon separately. In exhaust gas, however, they always occur in groups, which mean that it is necessary to explain their influence when they are in coincidence.

Schlüsselwörter

  • cavitation
  • emulsions
  • IC engines
  • fuel consumption
  • emissions
Open Access

Verification the Mathematical Model of Energy Efficiency of Hydraulic System

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 275 - 281

Zusammenfassung

Abstract

The article presents the laboratory verification of the mathematical description of losses and energy efficiency of the hydraulic transmission with proportionally controlled cylinder supplied by the constant capacity pump in the system of constant pressure is presented. The axial piston pump with pivoting rotor supplied to the system consisted of proportional directional control valve and linear motor – hydraulic cylinder at constant pressure, cooperating with an overflow valve. The choice of the analysed system is not accidental. There is always a view in literature about the very limited energy capabilities of a proportional control system. For this purpose, measurement methods were developed and a test stand was adapted. It consists of two systems: tested and loading. Measurements during the tests were recorded up to date on the computer hard disk. In order to allow for comparison of the total efficiency of the system with the efficiency derived from the simulation, the ki coefficients determining the energy losses of the individual components were calculated. Investigations have shown a high convergence mathematical description of energy losses in the elements of the system efficiency and reality. This allows accurate simulation determining the energy efficiency of the field at every point in its operation, i.e. at any speed and any load-controlled hydraulic cylinder. The speed and load range of the hydraulic cylinder can also be accurately simulated.

Schlüsselwörter

  • hydraulic systems
  • hydraulic transmission
  • energy efficiency
  • constant capacity pump
  • energy losses
  • mathematical model
Open Access

Experimental and Numerical Investigation of Connector with Elastomer Joint

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 283 - 289

Zusammenfassung

Abstract

This article presents works associated with the design, numerical analyses and experimental tests of an energy-absorbing mat designed for increasing the safety of the soldiers inside military vehicles, especially their legs. One of the most important branches of engineering interests is high technologies accompanying the safety of soldiers. Energy absorbing mats are one of an additional equipment of a military vehicle, which is directly targeted to increase leg safety during explosion of IED (Improvised Explosive Device) under vehicle. The presented invention allows protection legs of the crew’s feet resting on the floor of the vehicle during explosion of a mine or IED. In most solutions, crewmembers’ foot rests directly on the floor, causing serious injuries. The value of the load on the metatarsus and tibia is closely related to the overall vehicle structure, which generally has limitations in the use of available external and internal protection solutions. Energy absorbing mats are a universal solution because they are adaptable to any type of vehicle. Their role is particularly important in flat-bottomed armoured vehicles. The article will show the results of the analysis showing how the mat works. Experimental results will be compared with the results of numerical analysis. The analysis is conducted using the LS-DYNA explicit code.

Schlüsselwörter

  • elastomer
  • energy absorbing
  • LS-DYNA
  • experimental tests
  • FEM analysis
Open Access

Design Modifications of Pressure Boilers with Flat Endplates with Stress Relief Groove

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 309 - 316

Zusammenfassung

Abstract

Stress concentration is still present in the vicinities of structural notches in engineering structures. Zones with higher level of stress are particularly dangerous for structures subjected to fatigue or dynamic loads. The vessels with flat endplates with stress relief grooves are the common examples of such structures. Unfortunately, no clear evidence is given in existing codes how optimally to choose the circular groove radius and the optimal value of that radius depends on the dimensions of the boiler, operating conditions and the material used in manufacturing. Additionally, commonly used grooves with circular shapes are not optimal. Series of experimental tests, numerical or analytical studies presented in numerous articles confirmed these facts. In the presented article, the Authors proposed two-stage modification of the investigated vessel. The first step relies on change of the shape of the groove in the endplate, which provides certain reduction of stress concentration but still plastic deformations in the groove vicinity are not eliminated. The second step of the design modification is proposed for the boiler with the optimal elliptic groove configuration. In this step, some material is added around the top of the outer edge of the endplate. Two simple shapes are proposed for these parts - the short cylindrical ring or alternatively the circular ring welded on the top the endplate is used. For both concepts, the search of optimal dimension/parameters is performed. The numerical results of that study clearly show that the full elimination of plastic deformations near the groove is possible. The numerical analysis and optimizations were made with the well- established finite element software ANSYS, which is accepted by commonly used codes for designing of pressure vessels.

Schlüsselwörter

  • pressure boilers
  • flat ends
  • stress concentration
  • FEM analysis
Open Access

Diagnostics of a Common Rail System Using a Signal Analyser

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 317 - 324

Zusammenfassung

Abstract

Self-ignition engines are currently used to drive lorries, agricultural and road construction machines, as well as passenger cars. Common Rail supply systems are widely used in such engines. Arguments for using these systems include the simple construction of a system as well as practically unlimited control of fuel feeding (division of a fuel dose into several portions), which allows for controlling the fuel combustion process. This facilitates optimisation of the combustion process in limiting toxic emissions, which is the main evaluation criterion for modern combustion engines. Operation of an engine with a Common Rail system is controlled by an Electronic Diesel Control (EDC), which is responsible not only for controlling the supply system, but also for the diagnostics of the whole engine. The diagnostic monitors embedded in the controller supervise the operation of the supply system, but also of the whole engine, including the systems responsible for reducing toxic emissions released to the atmosphere, in accordance with the European On Board Diagnostic (EOBD) standard. Unfortunately, despite sophisticated diagnostic functions, defects sometimes occur in vehicles with engines with a CR system, which are not signalled by EOBD systems. In such cases, an additional tool is needed to help a diagnostician to identify the cause of improper operation of an engine. This article presents several examples to describe the diagnostics of a Common Rail system using an analyser of diagnostic electric signals to detect the cause of such defects.

Schlüsselwörter

  • Common Rail
  • EOBD
  • signals
  • electric
  • signal analyser
  • on-board diagnostics
Open Access

New Gyroplane Hub Connector with Positive Coning Angle

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 325 - 330

Zusammenfassung

Abstract

The article presents advantages and disadvantages of two blade teetering rotors with constructional dihedral angle greater than 0o. Several structural design solutions of rotor hub connector are shown in this work. However, the main attention is focused on innovative hub connector design and manufactured by Trendak Aviation Company during the project “Research and development works on innovative construction of aircrafts of weight over 560 kilograms”. Discusses structural advantages of the new rotor hub connector according to other construction. Also were raised issues related to the load of the gyroplane rotor during the flight, in particular the load of rotor blades root, during a gyroplane break manoeuvre, according to conning angle of rotor hub connector. The disadvantages of using the structural dihedral angle in teetering rotors are also presented, focusing on the rotor aeroelastic instability so-called waving, which from the literature analysed is concerned only with two blades teetering rotors. Performed a coarse analysis in SMOG program, prepared at the Institute of Aviation for the analysis of helicopter and gyroplanes rotors. The stability analysis of the rotor for a number of structural dihedral angle and blades setting pitch was performed. Basis of this analysis the stability boundary were determined for the analysed gyroplane rotor with connector hub with positive coning angle of 2.8o.

Schlüsselwörter

  • blade dihedral angle
  • waving
  • rotor instability
  • teetering rotor
Open Access

Optimizing of Parameters Dipping Metallization of Taguchi Method

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 332 - 337

Zusammenfassung

Abstract

Zinc coatings obtained by immersion metallization are an effective and economical way to protect against corrosion also for high carbon steels, foundry iron alloys. However, the difficulties encountered in surface preparation due to oxide contamination, as well as the presence of carbon (graphite) from the casting process or cast iron sludge, make cast irons zinc-plated by manufacturers reluctantly. The technological properties of the zinc baths and the technological properties of the coatings obtained vary considerably depending on the various impurity and alloying additives. The effect of zincing time significantly affects the thickness of zinc coatings and is dependent on the mass and thickness of the sample. The submerged object heats up faster or slower, depending on the thickness, and its temperature first reaches and then exceeds the melting point of the zinc. However, to avoid zinc over time, it is appropriate to respond to the current ISO standard EN 1461:2009, which specifies the minimum thickness of zinc coatings on steel substrate. The subject of the study was the optimization of parameters metallization using the Taguchi Method. The analysis took into account the influence of the immersion time and temperature of the bath of molten zinc on the thickness of the zinc coating. The test was conducted for three different times, i.e. 30, 60 and 150 seconds and for three different values of the temperature of the bath: 440, 460, 480 [°C]. In order to predict the thickness of the coating, multiple regression analysis was applied, which showed that the experiment was carried out correctly and falling within the limits of tolerance error

Schlüsselwörter

  • metallization
  • galvanizing
  • Taguchi method
  • optimizing
Open Access

Analysis of Wing-Engine Nacelle Aerodynamic Interference

Online veröffentlicht: 13 Aug 2021
Seitenbereich: 339 - 344

Zusammenfassung

Abstract

The article presents an analysis of the wing-engine nacelle flow interference phenomenon on the example of a light twin-engine commuter aircraft. The problems of propulsion system integration with the wing in airplanes are now frequently the subject of advanced optimization research performed by aircraft manufacturers. The shape of the engine nacelle and its connection with the wing determines the quality of the flow around the wing in that area. This is important for high-lift devices placed at the wing trailing edge behind engine nacelle used during the take-off and landing process. Additionally the flow is effected by the disturbances generated by working propellers, the presence of air inlets and an exhaust system of the engine. The article presents a process of numerical optimization of an engine nacelle rear part shape. The main goal of the process was to eliminate the flow disturbances caused by the engine nacelle-wing interference phenomenon. During analysis, the Adjoint Solver method was used to designate nacelle body areas where modification should have the most important impact on the flow quality. The results obtained from adjoint solver were used in the process of finding the optimum shape of the rear part of the nacelle using a parametric geometry generator powered by Ansys Design Modeler and PARADES software. Comparative computational analysis for selected geometries of the engine nacelle was performed using commercial Ansys Fluent solver. Ansys Fluent is an advanced computational solver based on the finite volume method for solving the Navier-Stokes flow equations. Several dozen of geometric shapes were analysed in the optimization process of the nacelle rear part. The final result was the shape of the engine nacelle with correct flow without separation and vortex structures. The article presents results of calculations and visualization of the flow pattern for analysed cases.

Schlüsselwörter

  • air transport
  • nacelle-wing integration
  • flow separation
  • adjoint solver
  • parametric design

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