基于时频分布的发动机异响特征分析及故障诊断研究

针对发动机异响故障振动信号的时变非平稳特性 ,引入一种重分配方法 ,得到干扰项少而分辨率高的重分配平滑伪魏格纳维尔分布 (RSPWVD) ,对发动机活塞敲缸响、活塞销响、曲轴轴承响、连杆轴承响、气门响和挺杆响等常见异响故障特征信号进行了比较分析 ,并提出了一种基于 RSPWVD的发动机多异响故障诊断策略。试验结果表明 ,采用 RSPWVD可以有效地提取异响故障特征信息 ,利用基于RSPWVD的诊断策略可以准确识别不同的发动机异响故障。

Engine Knock Signature Analysis and Fault Diagnosis Based on Time-Frequency Distribution

The vibration signal of the engine body is proved to be non stationary.Little work have been done on the diagnosis of mutli knocking problems simultaneously,such as cylinder knocking,piston pin knocking,crank bearing knocking,connecting rod bearing knocking,valve knocking and jib knocking etc.In this paper,a modified version of Smoothed Pseudo Wigner Ville Distribution based on the reassignment method is described,named Reassigned Smoothed Pseudo Wigner Ville Distribution (RSPWVD),which has little inference and fairly good resolution both in time and in frequency domain.It is shown that the RSPWVD can extract the features of different knocking problems effectively.A new fault diagnosis technique based on the RSPWVD for the engine multi knocking problem is proposed at the end.