Piston scuffing fault identification using engine vibration analysis

Pistons are always exposed to scuffing fault in an internal combustion engine. This fault can seriously damage piston and cylinder so that engine performance decreases drastically. The objective of this research is to investigate the effects of piston scuffing fault on the engine vibration in order to the usage of vibrations for detecting this fault. To this end، horizontal and vertical vibration signals of the engine were captured for healthy condition and scuffed piston and cylinder state. In this research، time-domain، frequency-domain and time-frequency domain analyses were used for the engine vibrations. In time-domain analysis، two parameters of root mean square and impulse factor were extracted from the vibration signals. Fast Fourier transform and short-time Fourier transform were employed for frequency-domain and time-frequency domain analyses، respectively. Moreover، two features of mean and energy were used in time-frequency domain analysis. The results showed that the piston scuffing fault generates significant vibrations in horizontal and vertical directions of the engine. Also based on the obtained results، the piston scuffing fault produced substantial vibrations in the frequency band of 2 to 6 kHz in the horizontal direction، whereas for the vertical vibrations of the engine، the frequency band of 4 to 6 kHz was affected. The obtained results demonstrated that the engine vibrations are capable of identifying the pistion scuffing fault، and can be used for its detection in engine.