Assessment of Engine Performance and Characteristics of Soot and NO<sub>X</sub> Emissions in the VCR Engine Fuelled with Different Sustainable Fuel Blends

In last few decades, many researchers working on the alternative fuel such as biodiesel that used in CI engine. It is proposed that the biodiesel can be good replace to the diesel due to the lower exhaust emissions, agricultural origin and improve the combustion process and engine performance. Rapeseed methyl ester (RME) blended with diesel fuel as sutainable fuel by 10% R10D, 20% R20D and 30% R30D in this study. Various compression ratio (CR) of 15 and 18 and different engine loads (25%, 50%, 75% and 100%) with keep engine speed constant. The results showed that the BTE increased with compression ratio and load. High brake thermal efficiency (BTE) was obtained from the combustion of R30D blend by 4.76% compared to the other blend and diesel under high load and 18 of CR. With increasing the engine load and CR, the thermal efficiency also gets better. The rewults showed that the BTE improved with increasing CR for all sutainable fuel blends, and it was more clear with R30D.The maximum brake specific fuel consumption (BSFC) was produced by R30D by 0.39 kg/kWh when CR is 17 and engine running at peak load. Furthermore, clear reduction was in case of R30D in comparison with R10D, R20D and diesel, espicaly with CR 18. The blends of RME showing enhancing in the engine performance compared to the diesel. With increasing both CR and engine load, the indicated mean effective pressure increases. It is indicated that the NOX emissions decreased with increasing the proportion of RME into the fuel blend and CR, while the high reduction was noted in HC and CO. A slight reduction in soot emission from the blends of RME was obtained compared to the diesel with increasing the CR.