Numerical Investigation on the Effect of Injection Timing on Combustion and Emissions in a DI Diesel Engine at Low Temperature Combustion Condition

One promising way to achieve low temperature combustion regime is the use of a large amount of cooled EGR. In this paper, the effect of injection timing on low temperature combustion process and emissions were investigated via three dimensional computational fluid dynamics (CFD) procedures in a DI diesel engine using high EGR rates. The results show when increasing EGR from low levels to levels corresponding to reduced temperature combustion, soot emission after first increasing, is decreased beyond ۴۰% EGR and get the lowest value at ۵۸% EGR rate. Soot and NOx emissions are simultaneously decreased at advanced injection timing before ۲۰.۵ ºCA BTDC in conjunction with ۵۸% cooled EGR rate in compared to baseline case.

Keywords:

Diesel engine , Low Temperature Combustion High EGR Rates , Combustion , emissions