汽油机分层废气再循环与稀薄混合气燃烧

为探索汽油机清洁燃烧技术途径 ,设计了 5气门汽油机馅饼状分层充气系统 ,试验对比了在分层充气前提下的稀燃和废气再循环对发动机排放特性的影响 ,并研究了两者叠加后对发动机性能的影响。试验结果表明 ,采用分层充气方式能够使废气再循环率达到 3 2 % ;在相同进气充量时 ,废气再循环与稀燃对改善 NOx 排放的效果基本相同 ;稀燃与废气再循环相结合可以获得比单纯稀燃或单纯废气再循环更好的综合性能 ,使 NOx 和 CO排放均降低到化学计量比无废气再循环情况下的排放指标的 10 %以下。稀燃与分层充气废气再循环相结合 ,简便可行 ,为研发低污染发动机提供了新思路

Lean combustion and EGR spark with charge stratification in an ignition engine

Various methods were investigated to lower emissions from gasoline engines using a 5 valve engine modified with a sandwich charge stratified intake system. The experiments studied the effects of lean combustion and exhaust gas recirculation (EGR) with charge stratification on the exhaust and engine performance. The test results show that the EGR rate with charge stratification can reach 32% and that the EGR mode and the lean combustion mode have similar effects on the NO x concentration in the exhaust gas for the same charge intake coefficient. The combined lean combustion and EGR reduced both the NO x and CO emissions to within 10% of that of the popular method of running on an air fuel ratio of 14.7 without EGR, which was better than either the EGR or lean combustion by themselves. The combination of the lean combustion and EGR with stratification is simple and feasible for developing less polluting engines.