Study on the correlation between combustion status and block vibration induced by piston slap

Abstract

The correlation between the combustion status and block vibration was studied at different engine speed, torque and oil temperature conditions. The frequency components lower than 8 kHz had a similar change trend with the peak value of combustion pressure at different speed conditions. The frequency components from 8 kHz to 25 kHz increased with engine speed and these frequency components were mainly affected by the inertia force. The spectrum energy of frequency components increased with engine torque due to the increase of combustion pressure. The maximum spectrum energy of frequency components below 20 kHz didn't show a particular trend due to the opposite effects caused by combustion pressure and oil damping at different oil temperatures. The frequency components higher than 20 kHz increased with the increase of oil temperature, which meant the frequency components were more sensitive to the oil damping.