Effect of compression ratio on the performance, combustion and emission of DI diesel engine fueled with ethanol - Diesel blend

The present work investigates the influence of compression ratio on the performance, combustion and emission characteristics of a single cylinder four stroke direct injections naturally aspirated diesel engine. Compression ratios such as 17.5:1, 18.5:1 and 19.5:1 were considered and varied by altering the dimensions of piston bowl by keeping the standard stroke volume. Tests were performed with five different blends of ethanol [E0, E10, E20, E30 and E40]. To maintain homogeneity and to prevent the phase separation, 1% of Ethyl Acetate plus 1% diethyl carbonate are added to ethanol diesel blend. The brake thermal efficiency found to increase at full load with higher percentage of ethanol at maximum compression ratio. The increase in compression ratio and ethanol blended fuel improves combustion and improves the performance of engine. Further there is a significant decrease in hydrocarbon (HC), Carbon monoxide (CO) and smoke emissions however there is an increase in Nitrogen oxides (NOx).