点燃式CNG发动机燃烧系统的优化

Optimization of Combustion System of Spark Ignition CNG Engines

在开发某CNG发动机的过程中,发动机出现了进气回火、排气放炮等性能不稳定现象.本文借助CFD软件模拟缸内流动与燃烧,对燃烧室结构进行了优化改进设计,对比了改进前后两种燃烧室内混合气燃烧和流动情况,分析造成两种燃烧室内燃烧差异的原因.通过分析对比湍动能、火焰传播与形成过程的差异诠释了原燃烧室产生回火放炮的原因.优化改进设计的燃烧室不仅有效解决了进气回火、排气放炮问题,还使发动机的转矩、功率比原来有所提高,同时燃料消耗率显著降低.

In developing the CNG engine,the unstable phenomena,such as tempering during air intaking and explosionduring exhausting,occur frequently.This paper is to optimize the structure of combustion chamber accordingto the simulations of gas flow and combustion inside the cylinder by using the CFD software.Comparisons are madebetween the new and original types of combustion chambers by analyzing the differences in terms of turbulence energyand the spread and development of flame.The new type of combustion chamber can not only effectively solvethe problems of tempering during air intake and explosion during exhausting,but also enlarge the torque and powerand minimize the fuel consumption rate of the machine.