发动机稳态与非稳态振动信号分析比较  

Analysis and Comparison of Engine Steady and Unsteady Vibration Signal

作　　者：孔令来[1] 肖云魁[2] 蒋国平[2] 王保民[2] 张玲玲[2] 夏天[2] 

机构地区：[1]天津职业大学,天津300402 [2]天津军事交通学院汽车工程系,天津300161

出　　处：《内燃机学报》2006年第1期72-77,共6页Transactions of Csice

摘　　要：主要探索了在发动机机械故障诊断中采用非稳态信号分析方法进行故障诊断。介绍了定转速非稳态数据采集器测试原理,讨论了短时傅里叶(Fourier)变换的原理与窗函数选择方法。应用它分析了发动机稳态与非稳态加速振动信号并进行了比较。试验与分析结果表明:定转速非稳态数据采集器能准确地测取发动机加速过程中所设定转速的振动信号;采用短时Fourier变换和窄带能量累加方法能有效提取加速振动信号中分析对象的故障特征,具有良好的重复性和稳定性;加速振动的信噪比远比稳态振动大得多。The fault diagnosis by using the method of unsteady signal in mechanical fault diagnosis of engine is analysed, and the measure principle of the unsteady data acquisition at fixed rotary-speed is introduced, and the principle of Short Term Fourier Transform （STFT） and the method of selecting the window function are discussed. The steady vibration signals and unsteady acceleration vibration signals of engine are analysed by using the STFT. The comparison showed that unsteady data acquisition at fixed rotary-speed can accurately measure the vibration signal of engine during the acceleration process. The STFT and the narrow band energy accumulation can effectively pick up the fault characteristics with better repeatability and stability. The ratio of signal to noise for acceleration vibration is far greater than that of steady vibration.

关 键 词：短时傅里叶(Fourier)变换 故障诊断 发动机 连杆轴承 非稳态振动 

分 类 号：TK418[动力工程及工程热物理—动力机械及工程] U464.1[机械工程—车辆工程]