Effects of ethanol blending with methanol-gasoline fuel on spark ignition engine performance and emissions

Abstract

This research investigated the effects of ethanol blending with methanol-gasoline as fuels in spark ignition engine and how it affects engine performance and emissions. Four ethanol-methanol-gasoline (GEM) blends were prepared with variable ethanol concentrations (0%, 5%, 10%, 15%) and constant methanol concentration (10%) and denoted as M10, E5M10, E10M10, and E15M10 in reference to each respective alcohol constituents. Physicochemical properties testing revealed that density and kinematic viscosity of GEM fuel blends increases with ethanol concentration. E15M10 has shown the most increase in density and kinematic viscosity with 10.7% and 18.7% increase respectively. In contrast, calorific value decreased as ethanol concentration decreases. E15M10 displayed the lowest calorific value at 16.9% lower than gasoline. Meanwhile, engine performance and emissions test showed that GEM fuels generally possess increased average Brake Thermal Efficiency (BTE) than pure gasoline. However, average Brake Specific Fuel Consumption (BSFC) for pure gasoline is lower. E15M10 displayed highest increment of BSFC at 17.2% average increase. Meanwhile, E10M10 displayed the highest improvement in BTE with an average of 9.4% increase. Exhaust emissions indicate that all GEM blends produced increased carbon dioxide (CO2) and oxides of nitrogen (NOx) emissions while carbon monoxide (CO) emissions decreases. E15M10 showed the most reduction in CO emissions with 90.6% decrease while E10M10 has shown the most increased CO2 and NOx emissions with 110% and 6.7 times increase respectively. In conclusion, up to 15% volume of ethanol blending with 10% volume methanol-gasoline was able to improve engine performance and emissions in terms of BTE and CO emissions.