Impact of high fuel injection pressure on the characteristics of CRDI diesel engine powered by mahua methyl ester blend

Highlights: • Mahua biodiesel blend is used as alternate fuel for the CRDI diesel engine. • Poor performance characteristics of biodiesel blend are enhanced through high fuel injection pressure. • High fuel injection pressure, improved the fuel atomization. • BTE increased and harmful emissions like HC, CO and smoke reduced. - Abstract: In this study, the effects of fuel injection pressure on the combustion, performance and emission characteristics of a common-rail diesel engine using mahua methyl ester blend (MME20) have been deliberated. When the mahua methyl ester blend was used as fuel, the specific fuel consumption (SFC) and NO_x emission increased, and brake thermal efficiency (BTE) decreased due to the combustion characteristics and fuel properties of MME20. The physical properties of the methyl ester blend such as viscosity and volatility affected the combustion process, in turn the engine performance. Particularly the atomization of fuel during the injection is related to the higher viscosity of methyl ester blend. In order to better utilization of mahua methyl ester blend, fuel injection pressure increased from 22 MPa to 88 MPa. High fuel injection pressure (88 MPa) exhibit higher BTE and better combustion characteristics when compared to that of other injection pressures. HC, CO and smoke level gradually falls with increase in the fuel injection pressure due to better mixture formation because of the well-atomized spray.