The effect of piston scratching fault on the vibration behavior of an IC engine

Abstract

Two-body and three-body abrasive wear which are the main wear modes in internal combustion (IC) engines, might occur in the area between piston and cylinder and could cause different failures of piston and cylinder such as scratching and scuffing. These failures could reduce the engine performance and cause the engine breakdowns in their severe form. This paper investigates the effect of piston scratching fault on the vibration behavior of an IC engine with the purpose of developing a practical way for the early detection of this fault. To this end, vibration test was conducted on the engine under two states namely, healthy and faulty. To generate the faulty engine state, scratching fault was simulated by cutting a groove into the piston skirt. Short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were employed in the analysis stage. The results showed that piston scratching fault caused a significant increase in the maximum, mean and energy of the engine vibration. The results of CWT method demonstrated that piston scratching fault excited the frequency band of 3–4.7kHz of the engine vibration. The obtained results indicated that piston scratching had significant and detectable effects on the engine vibration. Hence, the vibration analysis could be used as an effective tool for detection of piston scratching fault in IC engines.