Study on combustion process estimation using frequency information of diesel engine vibration acceleration signal

A novel frequency analysis method is proposed based on S-transform time-frequency domain analysis. Contrast between the new method and discrete fourier transform shows that the new method has better frequency resolution. Vibration acceleration measured when 195 single cylinder engine is running in different load, speed and injection advanced angle are analyzed using the new frequency analysis method. Contrast between frequency energy of vibration acceleration and maximum pressure increase rate is carried out and results show that there is close relationship between them. According to the analysis, a new method using frequency energy of vibration acceleration as characteristic parameter for combustion status is proposed. Verification is carried out in a four cylinder diesel engine and results show the characteristic parameter is feasible.