Investigating the role of fuel injection pressure change on performance characteristics of a DI-CI engine fuelled with methyl ester

This paper intended to investigate the impact of corn oil methyl-ester and diesel blends on performance, cornbustion and emission characteristics at varying injection pressure (210 and 230 bar). The tests were performed at a constant engine speed of 2000 rpm, and at two different engine loads of 5 and 10 Nm. Corn oil methyl-ester was produced by transesterification method in the study and then blended at 10%, 20% and 50% by volume into neat diesel fuel. The results presented that corn oil methyl-ester could improve combustion process owing to its high oxygen content in comparison with that of B0 fuel. High-injection pressure reduced the droplet diameter and accelerated the combustion process. This case has generally caused to high cylinder pressures. With respect to emissions, it was observed that CO (down to 66.67% at 230 bar) and HC (down to 52.38% at 230 bar) were sharply reduced depending on the increment of the blending rates of biodiesel while NOx (up to 22.45% at 230 bar) increased significantly. Depending on the increasing rate of corn oil methyl-ester in the blends, more fuel mass was injected into the combustion chamber and specific fuel consumption in biodiesel content-fuels were, therefore, higher than that of low injection pressure. Additionally, thermal efficiency decreased with the increment of biodiesel content owing to the lower heating value of biodiesel.