Time-domain analysis of relationship between engine cylinder head vibration acceleration and combustion process

The cylinder head displacement and vibration acceleration were respectively contrasted with the cylinder pressure signal and its rise acceleration signal in time domain. It is found that before the peak cylinder pressure occurring, the trend of the cylinder head displacement and the cylinder pressure signal are almost same, and the appearance timings of feature points of vibration acceleration and the pressure rise acceleration are very close. From comparison of the cylinder pressure, its rise rate and acceleration curves, it is found that the feature points on the pressure rise acceleration curve are nearly corresponding to the moments of combustion feature points e.g. the points of combustion start, the max. pressure rise rate, and the peak cylinder pressure, etc. Accordingly, the method to estimate the combustion process feature points from the feature points of cylinder head vibration acceleration signals was proposed. The method had been verified in model ZH195 single cylinder and model 495T diesel engines successfully.