The effect of diesel fuel blending with rapeseed oil and rme on engine performance and exhaust emissions

The purpose of this research is to determine the effect of Diesel fuel blending with rapeseed oil (RO) and RME on the brake specific fuel consumption of a direct-injection Diesel engine, fuel energy conversion efficiency and evaluate the quantitative emission composition changes and smoke opacity of the exhausts. Test results show that the application for engine fuelling of Diesel fuel and rapeseed oil RO25 (1:4 by volume) as well as rapeseed methyl ester RME20 (1:5 by volume) blends at low-to-moderate revolutions does not affect greatly the brake specific fuel consumption (bsfc) however at the rated speed and fully opened throttle the bsfc for blends RO25 and RME20 is higher by 4.7% and 11.9%, respectively. The maximum emission of nitrogen oxides NOx at the rated power for blend RO25 is lower by 11.7% and for blend RME20 is higher by 44.7% related to Diesel fuel. The smoke opacity, emissions of carbon dioxide CO2, monoxide CO and unburned hydrocarbons HC released into atmosphere from the engine run at fully opened throttle on blend RO25 are more or less similar to that of Diesel fuel whereas during operation at the rated power on blend RME20, because of higher specific fuel consumption, the smoke opacity increases to 42.6% and emission of CO2 to 9.9%.