中文摘要：

在AVLExcite平台建立发动机多体动力学分析的虚拟样机模型，通过相关参数设置，模拟活塞敲击故障，获取正常与故障状态下的活塞敲击力数据，从机理上分析故障引致机体异常振动原因。提取机体表面振动信号并利用时域、频谱和时频分析等方法，分析活塞敲击故障状态下机体表面振动信号特征，再通过小波包分解方法，构造总能量比参数进行故障诊断分析。结果表明，通过虚拟样机技术进行发动机活塞敲击故障仿真分析，对实际发动机故障诊断研究有很好的指导作用。

英文摘要：

The virtual prototype model of engine multi-body dynamic analysis was established on AVL Excite platform. By setting the corresponding parameters, the piston knocking fault was simulated, the data of piston knocking force in normal and fault state were acquired, and the reason leading to the engine body abnormal vibration were analyzed from the mechanism. The engine body surface vibration signal was extracted, the features of vibration signal in the fault state were analyzed with time-do- main method, frequency spectrum method and time-frequency analysis method, the parameter of total energy ratio was con- structed with the wavelet packet decomposition method, and the fault diagnosis and analysis were realized. The result indicates that the simulation analysis of engine piston knocking fault with the virtual prototype technology provides the good guidance for the actual engine fault diagnosis.