Abstract: The original air duct of a certain car engine has a relatively simple structure and there is no smooth transition at the junction of the inlet and outlet sections of the air duct, resulting in significant cross-sectional shrinkage and increased gas flow loss. We are now analyzing and adjusting the engine characteristic parameters to increase engine power and reduce engine fuel consumption. This article has made a preliminary modification to the original intake and exhaust duct model. After raising the protrusions where the intake and exhaust valve ducts are located by 2 mm, there is not much difference in the simulation results of the flow field between the intake and exhaust ducts and the original engine. The flow rate of the intake and exhaust ducts is only increased by about 1%, and the effect of improving the flow rate of the exhaust duct is slightly better. Therefore, in order to significantly improve the inflation efficiency and engine performance, it is necessary to improve the overall geometric structure of the duct. Therefore, this article has redesigned three schemes for the intake duct structure. From the calculation results, it can be seen that each scheme has a significant increase in intake flow rate, which can support the improvement of engine power. The analysis and research in this article can reduce oil consumption and improve the combustion efficiency of automotive engines.

Key words: Engine; Inlet and exhaust airways; Flow; Simulation analysis

摘要： 某车用发动机原气道由于结构较为简单，且在气道的进口段和出口段的交接处没有圆 滑过渡，截面收缩较大，导致气体流量损失增加。现对发动机特征参数进行分析调整，从而 提高发动机功率，降低发动机油耗。文章对原始进排气道模型进行了初步改型，将进排气门 导管所在凸台均抬高 2 mm 之后的进排气道与原机进排气道在流场的仿真结果上差异并不大， 进气道流量仅提高 1%左右，排气道流量的提升效果要稍好一些，所以，要想对充气效率和发 动机性能有大幅度的提升，须从气道的整体几何结构着手进行改进。因此，文章对进气道结 构重新设计了三个方案，从计算结果来看，各方案进气流量都有明显的提升，可支撑发动机 动力的提升。通过文章的分析研究可以减少石油的消耗，提高车用发动机燃烧效率。

关键词: 发动机；进排气道；流量；仿真分析