基于瞬时基频的发动机表面振动信号时域定位

Time Domain Location of Engine Surface Vibration Signal Based on Instantaneous Fundamental Frequency

发动机表面振动信号分析是发动机状态监测和故障诊断的有效方法,但是由于时域信号中耦合了多种激励源的响应,而对信号进行准确的特征定位比较困难。本文从发动机平均基频概念出发,提出基于瞬时基频的发动机表面振动信号时域定位方法,推导出曲轴转动时间与转角之间的对应关系,并将其应用于DA462型发动机表面振动信号分析中。应用BSWAVS302 USB便携式双通道声学振动分析仪,同步采集DA462型发动机曲轴相位信号和缸盖表面振动信号,以一、四缸上止点位置脉冲为初始时刻,根据配气相位计算各缸燃烧激励响应信号和气门响应信号,成功实现了对振动信号的时域定位,为发动机振动信号分析提供参考。

Analysis of engine surface vibration signals is an effective method for condition monitoring and fault diagnosis of engines.However,since the multi-excitation sources response is included in time domain signals,it is difficult to execute the signal character location accurately.In this paper,using the concept of the average fundamental frequency of the engine,a method of time domain location of the engine surface vibration signal is put forward based on the instantaneous fundamental frequency.The relationship between crankshaft rotation time and crankshaft angle is deducted,which is applied in the analysis of DA462 engine surface vibration signals.Using BSWA VS302 USB portable dual channel spectrum analyzer,the crankshaft phase signal and cylinder head surface vibration signal are collected synchronously.Taking the upper dead points of the first and the fourth cylinders as the initial,the combustion excitation response signal and the valve response signal of each cylinder are calculated according to the valve timing,and the time domain location for vibration signals is realized successfully.This work provides a reference for engine vibration analysis.