DETERMINING THE OPTIMAL SPARK IGNITION TIMING AND AMOUNT OF FUEL INJECTION OF A MOTORCYCLE ENGINE FUELED BY HIGH ETHANOL RATIO- GASOLINE ETHANOL BLENDS

Abstract

This paper presents the results of an experimental study that determined the optimal amount of injection and ignition timing of a motorcycle engine fueled by gasoline – ethanol blends at high ethanol proportion. Tests were carried out with the electronic fuel injection motorcycle engine on a specialized engine test bench. With 30% and 50% of ethanol (in volume) in blends (called E30 and E50) and without any adjustment, the maximum brake torque decreased by 8,20% and 23,44% as compared to case of gasoline fueled. When extending the fuel injection time to ensure air/fuel ratio around threshold 1, the brake torque of the engine increased but remained lower than the original gasoline engine by about 4,34% to 5,84% with the E30 and 5,11% to 6,47% with E50 fueling. When ignition timing is adjusted to reach maximum brake torque values, the engine performance of the ethanol-gasoline fueled engine is significantly improved. The useful torque of the E30 and E50 engines can be equal or even higher than the conventional gasoline engines, the improvement of 1,16% to 2,21% with E30 and 0,97% to 1,92% with E50 fueling were observed. Engine efficiency improved as energy consumption dropped on average from 2,69% to 8,87% with the E30 and 1,93% to 9,14% for the E50. HC, CO and NOx emissions tend to decrease by 17,83%, 3,43% and 8,46% on average with E30 and 34,09%, 11,70% and 28,65% with E50 at a speed of 4000 rpm, when the load changes.