ABSTRACT
Good thermal efficiency and high fuel economy of diesel engines are actually welcome attributes from the standpoints of suppressing global warming and conserving energy sources. However, high emission of oxides of nitrogen (NOx) and particulate matter associated with their unresolved trade-off is a major challenge that needs to be addressed by the researchers. Exhaust gas recirculation (EGR) and retardation of injection timings (ITs) are widely adopted in-cylinder techniques to lower NO emissions from diesel engines. Of late, a split/multiple injection strategy is being increasingly adopted for its potential to effectively address NOx, soot, and piston work trade-offs. The present work deals with the development of a quasi-dimensional numerical model to predict engine performance and emissions under various operating parameters. EGR levels have been varied from 0 to 30%, IT has been varied from 16° before top dead center (bTDC) to TDC, and two stages of split injections (25/75 and 75/25) are employed and their effect on emissions is discussed. Split injection of 25/75 is observed to be superior in controlling NO emissions than increasing EGR levels and retarded ITs without a penalty on engine performance.
