米勒循环发动机缸内气体流动与燃烧分析

在某1．6L发动机的基础上进行纵向开发，以此来实现高压缩比米勒循环发动机。利用大型三维计算流体动力学（CFD）软件STAR‐CD对采用进气门晚关策略的高压缩比米勒循环发动机进行数值模拟，对比分析了采用两种几何形状活塞的米勒循环发动机的缸内气体流动模式及燃烧过程。计算结果表明：经过结构优化的活塞方案相对于原方案可以获得较优的缸内流动及燃烧特性。计算结果将为实际开发中的高压缩比米勒循环发动机的活塞选型及燃烧室优化提供理论及数据支撑。

In-cylinder Gas Flow and Combustion Analysis of Miller Cycle Engine

A Miller cycle engine with high compression ratio was developed through the longitudinal development of a 1 .6 L engine .Then the numerical simulation of Miller cycle engine with high compression ratio and intake late closing strategy was conducted with CFD STAR‐CD software and the in‐cylinder gas flow mode and combustion process for Miller cycle engines with two kinds of geometry shape piston were compared .The results show that the optimized piston scheme has better in‐cylinder gas flow mode and combustion characteristics .The results provide the reference for the piston shape selection and the optimiza‐tion of combustion chamber in actual development of Miller cycle engine with high compression ratio .