Analysis of transmission pathways of combustion-induced vibration in a diesel engine using wavelet cross-correlation analysis method

We experimentally investigated the transmission pathways of the combustion-induced vibration by analyzing the in-cylinder pressure, the accelerations on walls near the combustion chamber and the main bearing with wavelet cross-correlation analysis which can obtain both time delay and the correlation on the time between two signals in the frequency domain. The analysis shows that there are three possible transmission pathways of vibration from the combustion impact. First is a direct transmission from the combustion chamber to a wall near the combustion chamber or a wall near the main bearing via an engine surface wall, second is the transmission from the combustion chamber to a wall near the main bearing via the piston, connecting-rod and the crankshaft, and third is a transmission from the combustion chamber to a wall near the main bearing and there is no transmission to a wall near the combustion chamber.