Influence of ethanol-gasoline fuel fractions on variable compression ratio engine

Abstract

Increase in demand of ethanol as blending fuel with gasoline is increasing. For noting the performance of the engine, experimentations are required to be done on engine, fuelled with various percentages of ethanol in gasoline. In this study, fuel fractions of ethanol and gasoline were taken for observing the performance of spark ignition engine. One-cylinder gasoline engine was used for conducting the experiments and to analyse the effects of ethanol-gasoline fuel fraction on performance of the engine. The engine was tested at Full Open Throttle condition. The load on the engine was changed by changing the load on Eddy Current Dynamometer to vary the engine speed from 1300 to 1700 rpm in the interval of 100 rpm. Gasoline is blended with ethanol to make five fuel fractions from 0 % ethanol (E0) to 40 % ethanol (E40) in gasoline at the interval of 10% by volume. Engine performance was observed at various Compression Ratio (CR) of the engine as 7,8,9 and 10. Calorific Value (CV) of the fuel fractions observed decreasing from E0 to E40 as CV of ethanol is less than base gasoline. Increase in Brake Specific Fuel Consumption was not very significant with rise in ethanol percentage. Power outputs in terms of Brake Power (BP) was increasing with increase in speed of the engine and observed decreasing with increase in ethanol percentage at constant CR. However various engine output parameters like BP, Mechanical Efficiency found decreasing with increase in fuel fractions ratio. Brake Thermal Efficiency (BTE) was observed decreasing with increase in fuel fractions. However, BTE was observed increasing with increase in CR.