Investigation of high fuel injection pressure variation on compression ignition engines powered by jatropha oil methyl ester-heptanol-diesel blends

Abstract

The fast depletion of the petroleum reserves and the rising environmental threats have created an urgent need for sustainable-alternate fuels for the transport and agricultural sectors. In this regard, the ternary blends (diesel–biodiesel-alcohol) have the potential to address the above concerns as they offer huge potential in mitigating exhaust emissions and enhancing engine performance. In the present work, jatropha biodiesel and heptanol have been used as oxygenated additives in the ternary blends in order to save considerable quanta of diesel fuel by restricting its volumetric content to only 40 %. In addition, the fuel injection pressure (IP) is a vital factor that determines the performance and emissions of CI (Compression Ignition) engines. The impact of variations of IP on the performance and emission of CI engine fuelled with ternary blends needs fresh investigation. The previous works lack the analysis of high IP variation in diesel engine fuelled with ternary blend that involve higher alcohol. This experimental work aims to investigate the improvement in CI engine performance and reduction in the exhaust emissions by applying varied IP to the engine powered with diesel-jatropha biodiesel-heptanol blends. In this context, four different ternary blends were prepared by varying biodiesel and heptanol contents from 20 to 50 % and 10–40 %, respectively. The ternary blends were tested in a single-cylinder, four-stroke, direct-injection CI engine by varying the IP from 400 to 500 bar at 10 and 20 Nm engine loads while maintaining the engine speed at 1800 rpm. The results indicated that DBOHep20 achieved a maximum reduction of CO and smoke emissions by 57.4 % and 91.6 %, respectively. The lowest NOx emission was achieved by DBHep40 which was found to be 13.27 % lower than diesel. In the case of engine performance, DBHep40 resulted in lowest BSFC and highest BTE which were found to be just 12.5 % higher and 3.9 % lower than diesel, respectively. The lower IP leads to lesser emissions with a slight compromise with engine performance.