Engine Performance, Emission and Combustion Characteristics of a Common-rail Diesel Engine Fuelled with Bioethanol as a Fuel Additive in Coconut Oil Biodiesel Blends

Abstract

In the present work, an experimental investigation was conducted to investigate the effect of using bioethanol as additive to biodiesel-diesel blends on the engine performance, emissions and combustion characteristics of a four-cylinder, high-pressure common-rail direct injection diesel engine. Two different mixes fuels: B20 (20% coconut biodiesel+80% diesel) and B20E5 (20% coconut biodiesel+5% ethanol+75% diesel) were tested and compared with baseline diesel. The tests were performed under steady state conditions at constant speed of 2000rpm with three different engine load (0.17MPa, 0.69MPa and 1.20MPa). The results indicated that higher brake thermal efficiency and brake specific fuel consumption were observed when operating with biodiesel and ethanol-biodiesel fuel blends. The ethanol-biodiesel blends showed lower NOx, smoke and CO emissions compared to baseline diesel fuel. In terms of combustion characteristics, B20E5 shows slightly lower in peak pressure and peak HRR at an operating load of 0.17MPa.