To Analyze Unstable Vibration Signal of Diesel Engine Basing on the Theory of Cyclical Spectrum

This paper searches a way to diagnose diesel engine mechanical faults by analyzing unstable vibration signal. At first, it introduces the theory of Second-order Cyclical Spectrum(SOCS) and the unstable datum acquiring principle, then analyzes the unstable vibration signals of engine by the method of SOCS. The results show that the unstable datum acquirer whose starting rotary speed is preset can measure the accelerating vibration signals of engine, and the sampling data have good stability and repeatability. The method of SOCS can effectively pick up the fault feature frequencies hiding in the accelerating vibration signals.