Influence of fuel injection timing in a DME based CI engine at low load

Dimethyl Ether (DME) is a possible clean substitute to diesel for CI engines. A computational study was done to understand the influence of time of injection on performance and emissions from a DME based CI engine. Due to the symmetry of the engine, the simulations were conducted on a 60 o sector of the cylinder from closure of intake valve to opening of exhaust valve. The start of fuel injection (SOI) time was varied from - 25 o b T D C to - 2 o b T D C . Simulated results for pressure traces, heat release rates, IMEP, and CO and NO emissions are presented. Maximum IMEP was obtained for SOI of - 2 o b T D C , and it decreased with advanced injection. The decrease was small up to advance of - 10 o b T D C . NO emissions peaked around SOI of - 10 o b T D C to - 15 o b T D C . In contrast, CO emissions showed an opposite trend.