Piston Slap Induced Noise and Vibration of Internal Combustion Engines (1st Report, Theoretical Analysis and Simulation)

This paper presents an analytical model of the impact force and the vibratory response of cylinder liner induced by the piston slap in internal combustion engines. In this method, the equation of motion for the coupled system of piston and cylinder liner is derived, taking account of several resonant modes of the cylinder liner to simulate accurately time histories of the impact force and the vibratory response. As practical example, the piston slap phenomenon in a six cylinder diesel engine with wet liners is analyzed at rotational speed N = 1800, 2300 rpm, using the dynamic characteristics of the cylinder liner that were experimentally determined. The calculated results show that the impact force is amplified by the piston-liner impact vibration as compared with the piston side force and that both the time history and the frequency spectrum of cylinder liner acceleration agree well with measured results.