气门重叠角对HCNG发动机回火性能的影响

为研究某高压缩比HCNG发动机的回火特性,进行了发动机回火工况台架试验,结合试验数据,建立HCNG发动机三维仿真模型,对不同气门重叠角下的回火性能进行仿真计算。试验与仿真结果表明:压缩比越高,发动机越容易回火;其他条件不变,较小的点火提前角容易引起回火;原机气门重叠角较大,压缩比提高,导致进气口富氢新鲜充量受热,这是造成回火的重要原因;随着气门重叠角的减小,发动机功率以及最高燃烧压力降低,当气门重叠角为0°时,可有效避免回火。

Influence of Valve Overlap on HCNG Engine Backfire

In order to research the backfire performance of HCNG engine with high compression ratio ,the bench test of back‐fire conditions was carried out .The 3D model of HCNG engine was built based on the test data and the backfire characteristics under different valve overlaps were simulated .The test and simulation results show that the backfire phenomenon is easier to occur for the engine with higher compression ratio .In addition ,smaller ignition timing can easily cause backfire with other op‐erating conditions unchanged .The large valve overlap improves compression ratio so that the enriched hydrogen is heated , which is an important factor for backfire .The engine power and maximum combustion pressure decrease with the decrease of valve overlap and the backfire phenomenon can be avoided when the valve overlap is 0° .