Modelling and evaluating piston slap-induced cavitation of cylinder liners in heavy-duty diesel engines

Cavitation erosion of cylinder liner seriously affects the operational reliability and service life of heavy-duty diesel engines. The accuracy of the modeling-based cavitation risk evaluation is limited by the unclear correspondence between cylinder liner vibration and coolant cavitation. This report is intended to investigate the correspondence between cylinder liner vibration and coolant pressure by combining vibration cavitation test, pressure gradient calculation, and visualization observation. The cavitation risk of the cylinder liner under the piston slap is quantitatively analyzed based on a nonlinear structural dynamics model that incorporates the piston-cylinder liner nonlinear collision, piston thermal deformation, and preload of cylinder head. The results show that the occurrence of cavitation will cause a nonlinear relationship between the cylinder liner acceleration and the coolant pressure. The engine under study has a high risk of cavitation when the cylinder liner acceleration exceeds 1189 m/s2. The difference in cavitation risk for each cylinder is related to the structural modal characteristics of the crankcase. In addition, the effect of piston-liner clearance and piston pin offset on the cavitation risk is investigated based on the dynamics model.