中文摘要：

为探究非均匀发火多缸柴油机燃烧故障的诊断和定位方法，以轴系扭振理论为基础，首先分析非均匀发火柴油机谐波相位与发火间隔角的关系。接着基于AVL-EXCITE建立以50°/70°间隔发火的某V12柴油机轴系扭振集总参数计算模型，并设置不同负荷下各缸单缸失火故障，仿真计算其0.5谐次的相位和幅值，然后对该V12柴油机进行试验研究。仿真计算结果和部分缸失火故障试验数据的对比表明该V12机的0.5谐波相位以25°/35°交替转换，验证了理论分析的正确性。基于此提出根据0.5谐次幅值判断有无故障、A1缸基准相位差定位故障位置的故障诊断规则。

英文摘要：

The method of fault diagnosis and location of non-uniform ignition multi-cylinder diesel engines is studied.The relationship between the harmonic phase and the firing interval angle of the non- uniform ignition diesel engines is analyzed based on the shafting torsional vibration theory. Then, the lumped parameter model of a V12 diesel engine shafting torsional vibration at 50/70 degree interval ignition is established with AVL software. Meanwhile, the misfire fault of each single cylinder under different loading is set, and the simulation calculation for 0.5-order harmonic phase and amplitude is done. Finally, the V12 diesel engine is tested. The comparison of simulation results with some cylinder misfire tests results shows that the 0.5-order harmonic phase of the V12 machine can be alternated between 25 degree and 35 degree. So, the correctness of the theoretical analysis is verified. On this Basis, a fault diagnosis method is proposed. In this method, the 0.5-order harmonic amplitude is utilized to determine whether the fault occurs and locate the fault according to A1 cylinder’s reference phase-difference.