基于一台直列三缸Atkinson循环混合动力专用汽油机的试验数据，针对混合动力发动机常用工况点（2 000 r/min，0.6 MPa）创建了二次喷射下的发动机缸内工作过程CFD仿真模型，并进行了有效性验证。在此基础上，开展了无EGR与7%EGR率条件下的点火提前角扫描仿真研究，分析不同EGR率对Atkinson循环发动机燃烧和排放的综合影响。结果表明：引入EGR可将平均涡流比提高0.05，降低燃烧过程的湍动能，使滞燃期平均延长5°，燃烧持续期平均延长10°；同时，EGR可将NOx排放降低超过80%，但导致CO升高2倍。点火正时对涡流比和湍动能的影响甚微；在7%EGR率工况下，随着点火提前角增加，NOx排放的增幅更小，CO排放下降更快。

Based on experiments conducted on an inline three-cylinder Atkinson cycle gasoline engine designed for hybrid applications, the CFD model of in-cylinder combustion under dual injection was developed for a common hybrid engine according to the operating conditions of 2 000 r/min and 0.6 MPa. The model was further validated for accuracy. Then the ignition timing sweep simulations were carried out under conditions of no EGR and 7% EGR rate to investigate the comprehensive effects of varying EGR rates on combustion and emissions in the Atkinson cycle engine. The results showed that the introduction of EGR increased the average tumble ratio by 0.05, reduced the turbulent kinetic energy during combustion, extended the ignition delay period by an average of 5° and prolonged the combustion duration by an average of 10°. Furthermore, EGR reduced NOx emissions by over 80%, but doubled the increase of CO emissions. Ignition timing had little effect on the tumble ratio and turbulent kinetic energy. Under the 7% EGR condition, increasing the ignition advance angle led to a smaller increase in NOx and a more significant reduction in CO emissions.