基于多缸运动的天然气发动机进气均匀性计算方法

Calculation Method of Intake Uniformity of Natural Gas Engine Based on Multi-Cylinder Motion

针对常规废气再循环(exhaust gas recirculation,EGR)率均匀性计算方法不适用于各缸进气量分析的问题,基于CONVERGE软件建立了考虑气门和活塞运动的多缸计算方法,并分析了某国六天然气发动机的进气均匀性。结果表明:采用多缸方法得到的EGR率均匀性计算结果与采用常规方法得到的结果一致,并且多缸方法还能获得各缸的进气量和当量比及各缸的涡流比、滚流比和湍动能等表征缸内流动状态的参数,拓展了计算能力。基于仿真分析和台架试验的结果表明该款发动机的进气均匀性满足设计要求。

Due to the conventional calculation method of exhaust gas recirculation rate(EGR)uniformity was not suitable for the analysis of intake quantity of each cylinder,a multi-cylinder calculation method considering the movement of valves and pistons was established based on CONVERGE.The intake uniformity of a ChinaⅥnatural gas engine was analyzed.The results show that the EGR rate obtained by multi cylinder method are consistent with those obtained by conventional method.Moreover,the intake quantity,equivalent ratio of each cylinder and the flow parameters in cylinder such as the vortex ratio,tumble ratio and turbulent kinetic energy of each cylinder can be obtained by the multi cylinder method which has extended calculation ability.Based on the results of simulation analysis and bench test,the intake uniformity of the engine can meet the design requirements.