Effects of oxygenate additive mixture on the performance and emission characteristics of a biodiesel fuelled compression ignition engine

An experimental investigation was conducted to discover the effects of oxygenate mixture as additives in Jatropha biodiesel on the performance and emission characteristics of a direct injection compression ignition engine. The experiments were conducted in an instrumented single cylinder air cooled four stroke direct injection diesel engine (running at constant speed of 1500 rpm and injection timing of 26 degrees bTDC), AC alternator and an electric loading device. Four oxygenate additives, namely, Dimethyl carbonate (C3H6O3), Ethylene glycol (C2H6O2), Propylene glycol (C3H8O2) and 2-Butoxyethanol (C6H14O2) were selected, and nine different combinational oxygenate test fuels were prepared attaining ratios of 1, 2 and 4% volume of oxygenates with biodiesel. Reduction in CO by 60%, Unburned HC by 11% and smoke emissions by 27% were observed for the test fuels without conciliating the brake thermal efficiency improvement by 6%, while NO emission increased marginally by 4%.