Pollutant emissions and fuel efficiency prediction for a downsized spark ignition engine using a 0-dimensional combustion model

摘要

Today, gasoline engines often have the reputation of low cost but high fuel consuming engines. However, the spark ignition (SI) engine still has a great potential in terms of thermal efficiency, notably through the use of the downsizing approach combined with direct injection, variable valve actuation technologies and alternative fuels such as biomass derived alcohols. Combining all the aforesaid solutions opens new perspectives of development for SI engines with a high number of parameters to optimize (supercharging architecture, VVA, injection strategies, nature of the fuel...). In this context, powertrain simulation tools are an interesting complement to tests. In fact, they allow to rapidly evaluate the real potential of a given combination, provided the models correctly describe aerodynamic and combustion processes in the cylinder. Notably, the occurrence of knock should be predicted and the effect of enrichment or spark advance variations on auto-ignition and pollutant emissions must be reproduced. For this purpose, a 0D coherent flame model based on the reduction of a 3D CFD combustion model is proposed in this study. This model is validated on a highly downsized GDI engine fuelled with pure gasoline or gasoline ethanol blends and is used to recover maps of specific consumption and pollutant emissions.