Vibration signature analysis for engine condition monitoring and diagnosis

In this paper, the vibration signals taken experimentally from a typical 4-cylinder IC engine are analyzed. An LMS Pimento analyzer is used along with appropriate sensors (accelerometer and tachometer). Different points were chosen for acceleration (velocity) pick-up (e.g., points adjacent to each cylinder, a point on the cylinder head and another on the engine mount). Valve maladjustment and ignition failure were introduced and the effects were investigated. The test results of healthy/faulty engines were recorded and then processed and analyzed in time-frequency domain. The results showed that correlations could be found between engine performance and the output signal spectra, STFT (Short Time Fourier Transform), and CWT (Continuous Wavelet Transform) patterns. These facts demonstrate the possibility of using vibration signals for engine monitoring and diagnosis.