CAJ | 학술논문

以常见的机械磨损故障———气门间隙过大故障为例进行了试验研究，提取缸盖振动加速度信号进行分析，发现故障状态的时域信号有明显低频周期性冲击，但在频谱的低频区间未现冲击频率；同时，在故障状态频谱中，3000～4500 Hz范围的高频段振动能量有显著增加。通过小波包分解方法对信号分解至该故障特征频段，再进行希尔伯特解调分析，解调谱现显著的对应低频冲击的频率成分，可作为故障识别特征。分析结果表明，气门间隙过大故障造成的冲击引起缸盖或其部件共振调制现象，综合运用上述时域、频谱和共振解调分析，可对配气机构磨损故障进行故障特征提取，从而为准确诊断故障提供依据。
이상견적궤계마손고장———기문간극과대고장위례진행료시험연구，제취항개진동가속도신호진행분석，발현고장상태적시역신호유명현저빈주기성충격，단재빈보적저빈구간미현충격빈솔；동시，재고장상태빈보중，3000～4500 Hz범위적고빈단진동능량유현저증가。통과소파포분해방법대신호분해지해고장특정빈단，재진행희이백특해조분석，해조보현현저적대응저빈충격적빈솔성분，가작위고장식별특정。분석결과표명，기문간극과대고장조성적충격인기항개혹기부건공진조제현상，종합운용상술시역、빈보화공진해조분석，가대배기궤구마손고장진행고장특정제취，종이위준학진단고장제공의거。
For the mechanical wear fault of large valve clearance ,the acceleration signal of cylinder head vibration was collect‐ed by the experiment .It was found that there was low frequency periodic impact in time domain and was not impact frequency in frequency domain in fault state .Meanwhile ,the vibration energy in 3 000‐4 500 Hz increased evidently in the spectrum of fault state .The signal was decomposed to the fault characteristic frequency band by the wavelet packet decomposition and was demodulated by Hilbert demodulation analysis .The frequency components of low frequency impacts in demodulation spectrum were found ,which could be used as the feature of fault diagnosis .The results show that the impact of large valve clearance fi‐nally leads to the resonant modulation phenomenon of cylinder head or other components .Therefore ,the feature of valve‐train wear fault can be extracted by the time domain ,frequency spectrum and resonance demodulation analysis ,which provides the basis for accurate fault diagnosis .