Multidimensional engine modeling: NO and soot emissions in a diesel enginewith exhaust gas recirculation

The effects of EGR(Exhaust Gas Recirculation) on heavy-duty diesel engine p erformance, NO and soot emissions were numerically investigated using the m odified KIVA-3V code. For the fuel spray, the atomization model based on th e linear stability analysis and spray wall impingement model were developed for the KIVA-3V code. The Zeldovich mechanism for the formation of nitric oxide and the soot model suggested by Hiroyasu et al. were used to predict the diesel emissions. In this paper, the computational results of fuel spra y, cylinder pressure, and emissions were compared with experimental data, a nd the optimum EGR rates were sought from the NO and soot emissions trade-o ff. The results showed that the EGR is effective in suppressing NO but the soot emission was increased considerably by EGR. Using cooled EGR, soot emi ssion could be enhanced without worsening of NO.