Impact of compression ratio, fuel injection pressure and timing on the behaviour of compression ignition engine operating with ethanol-enriched WCOME blends

Abstract

Compression ignition engines’ performance, emission and combustion characteristics are studied using ethanol-enriched waste cooking oil methyl ester (WCOME) varying compression ratio, fuel injection pressure and timing under full load conditions. The fuel blend of base fuel (10% WCOME and rest diesel) with 5% ethanol was tested at different compression ratios of 18, 19, 20 and 21; injection pressures of 200, 220, 240 and 260 bar, and injection timing of 21°, 23°, 25° and 27° before top dead centre. The carbon monoxide, hydrocarbon emission and smoke opacity of the blend were 16.3%, 19.6% and 36.8% less respectively than that of diesel at a fuel injection pressure of 240 bar. The lowest brake-specific energy consumption obtained is 1.06% less than that of diesel. Higher brake thermal efficiency, lower brake specific energy consumption, and reduced carbon monoxide and hydrocarbon emissions except nitrogen oxides are obtained for fuel injection timing of 25° before the top dead centre. The peak of cylinder pressure at 65.47 bar is obtained for the fuel blend at 9° after the top dead centre and 240 bar fuel injection pressure.