Abstract: In order to research the backfire mechanism of one HCNG engine with high compression ratio, an experiment of backfire conditions was carried out. On the basis of the engine specifications and experimental data, a 3-D model of HCNG engine was established by AVL-Fire software, which made the simulation calculation of backfire conditions. The test and simulation results show that, the engine is easier to backfire at the condition of higher compression ratios; if other conditions keep unchanged, backfire is likely to happen when the ignition advanced angle is closer to top dead center (TDC); large valve overlap and high compression ratio cause the waste gas with high temperature back flow to the intake ports, which is one of the causes of backfire; the invalid ignition close to the TDC of exhaust stroke increases the gas temperature near the intake valve, which raises the backfire trend.

Key words: vehicle engineering, HCNG engine, backfire, 3-D simulation, compression ratio

摘要： 为研究某高压缩比HCNG发动机回火机理，进行了发动机回火工况台架试验。结合试验数据，利用AVL-Fire软件建立HCNG发动机三维仿真模型，对回火工况进行仿真计算。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；由于气门重叠期较大，压缩比提高，导致高温废气回流到进气道，这是造成回火的原因之一；排气冲程末端 的无效点火，使得进气门附近的温度进一步提高，加大了回火的趋势。

关键词: 车辆工程, HCNG发动机, 回火, 三维仿真, 压缩比