Optimization of LPG/Ethanol Blend for Better Performance and Reduced Emissions

Strict environmental regulations and depleting conventional fuel resources have forced us on finding alternatives fuel resources. LPG and Alcohols have gained attention of many researchers as reliable energy source because of their high octane number and also a clean energy source. In this study, experiment was conducted to determine the effects of ethanol blend with liquefied petroleum gas (LPG) on SI engine performance and exhaust emissions. The experiment was conducted on 4.4kW SI engine at 100% throttle in which the LPG was fed using gas carburettor and ethanol using gas fuel inductor installed on injection manifold. The ethanol was converted to gaseous form using external heating source. Tests were conducted to determine the thermal efficiency, brake power and analyze the exhaust emissions from the engine at 20%, 30% and 40% of ethanol concentration at a speed of 1500rpm, varied loads on engine and different equivalence ratios. We found that Carbon Monoxide and Hydrocarbon emissions were reduced drastically due to the leaning effect caused by Ethanol. Also there was an increase in thermal efficiency and brake power of engine as the equivalence ratio was increased. The optimum percentage of ethanol in the blend was found to be 30% for maximum power and least emissions.