废气再循环对侧卷流燃烧系统性能的影响

A lateral-swirl combustion system(LSCS) was used to deal with the challenges of deteriorated combustion performance and increased soot emission after implementing exhaust gas recirculation(EGR) in direct-injection diesel engines. An in-cylinder combustion 3-dimensional simulation of the LSCS and a traditional ω combustion system was conducted under medium and high load conditions at the speed of 1 800 r/min and 2 500 r/min，respectively. The results indicate that，under the same NO_x emission levels，the LSCS allows a higher EGR rate compared to the ω combustion system，resulting in an increase of the indicated power from 1.1% to 1.3%. Under the same indicated power conditions，the LSCS can accommodate a higher EGR rate while reducing NO_x emissions by 35.9% to 45.6% and soot emissions by 27.9% to 49.4%，respectively. Furthermore，the results suggest that the wall-flow-guided structure of the LSCS promotes the fuel jet expansion in the cylinder to be fully mixed with the air，enhancing its compatibility with EGR.