Vibration monitoring of marine diesel engine using time series method

摘要

This paper conducts an investigation on diesel engine condition monitoring using cylinder head vibration signals. In order to analyze these signals, both time series analysis and Fourier spectrum method are adopted. The cylinder head vibration signals are measured and analyzed for detecting the working conditions of valve clearances and engine cylinder loads. The characteristics of engine surface vibration under different working conditions are described, the properties of cylinder head vibration induced by valve impacts and combustion forces are discussed, and some criteria for diesel engine vibration monitoring are proposed. Experimental investigations were carried out on a turbocharged four-stroke 6-cylinder marine diesel engine. The results indicate that the changes of cylinder head vibration character parameters can be used to identify the variations in valve clearances and cylinder loads. The relationships between character parameters of surface vibration and engine working conditions are presented. Moreover, this investigation shows that autoregressive spectrum is smoother than Fourier spectrum, with more accurate frequency locating, especially suitable to short data records, so it is more effective and suitable to diesel engine condition monitoring.