Optimizations of diesel fuel injection parameters and in-bowl mixture preparation

摘要

To improve fuel economy in heavy-duty diesel engines under stringent emissions regulations. an examination was made of injection parameter optimization by means of electronically controlled common rail injection system and engine modifications.Firstly a new pilot injection concept was studied. Secondly, the swirl ratio and combustion chamber geometry were modified so as to optimize air-fuel mixing and to strengthen the pilot injection effects. Finally, for the purpose of further NO{sub}xreductions, the potential of the combined use of EGR and pilot injection was examined. However, the combination of pilot injection with EGR showed little improvement in the NO{sub}x-PM trade-off since smoke increased especially in low-load conditions.