The Performance and Emission Characteristics Assessment of Hybrid Biodiesel/Ethanol Blends in a Diesel Engine

In this study, a biodiesel blend was developed from the waste cooking oil methyl ester (WCOME) and soya bean oil methyl ester (SBME), namely, the optimum blend of WCOME-SBME (BM100) biodiesel. This biodiesel-biodiesel mixture (hybrid biodiesel) was in turn blended with 15 % of ethanol to give a biodiesel mixture-ethanol blend (BME15). The biodiesel-biodiesel mixture has a better density than the individual biodiesels, SBME had lower viscosity compared to BM100 and WCOME. The presence of ethanol in the hybrid biodiesel blend reduced both kinematic viscosity and the high density of the blend. BM100 also exhibited a better heating value compared to the individual biodiesels. Engine performance and emissions were tested using diesel (D100), WCOME, SBME, BM100, and BME15, and experimental results obtained compared with predicted using Diesel-RK software. The results indicated that at the maximum speed of 2500 rpm, BM100 performed better in terms of brake power (BP), brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), and brake mean effective pressure compared to the individual biodiesels (WCOME and SBME) but marginally poorer to D100. The BTE of BME15 is comparable to BM100. On the other hand, BME15 exhibited better emission characteristics having the lowest NO, particulate matter (PM), and hydrocarbon (HC) emissions compared to D100, WCOME, SBME, and BM100. Overall, when both engine performance and emission are considered BM100 increased engine performance compared to WCOME and SBME while BME15 is more effective in decreasing NO, PM, and HC emissions.