Modeling the effects of split injection scheme on soot and NO emissions of direct-injection diesel engines by a phenomenological combustion model

摘要

A multizone phenomenological combustion model, in which the fuel burn rate is governed by the rate of fuel vaporization and mixing, is developed to study the effects of split injection schemes on NO and soot emission of direct-injection diesel engines. This model is calibrated with the experimental data of a single injection case. Comparison between the results calculated by the model and experimental results shows that the model has a good predictive capability for cylinder pressure, heat release rate, NO and soot emissions. The study of split injection parameters, including the delay dwell between injection pulses, the fuel quantity injected in the second pulse and the fuel pressure of the second injection, is carried out. The results predicted by the model show that the soot can be effectively reduced without increasing NO emission and fuel consumption with the split injection in which 10-30% of total fuel is injected in the second injection at about 15 deg CA after top dead center.