ABSTRACT
In this paper, low pressure EGR and water addition were considered as candidate solutions for NOx reduction in the high BTE region, where HP EGR is insufficient to reduce NOx emission. To overcome possible wet wall and lubricant dilution issues caused by water addition, a reliable intake port water injection strategy is proposed in this study, which ensures the water entering the cylinder in the form of vapour. This water injection strategy has been studied and compared with the LP EGR strategy at high load operating conditions with respect to combustion, emission and performance. What is more, the potential of combined water injection and HP EGR strategy for further NOx emission reduction was also tested, with the aim of meeting future near-zero emission regulation.
