Stick-slip oscillations of an engine front-end accessory drive system with a mechanical tensioner

摘要

This article is aimed to investigate the stick-slip oscillations of an engine front-end accessory drive system with a mechanical tensioner. Based on several assumptions, a generic dynamic model of rotational vibrations of an engine front-end accessory drive system with arbitrary number of accessory pulleys and one mechanical tensioner is established. In this model, the tensioner dry-friction torque is approximated by a hyperbolic tangent function with a scaling factor to control the sticking zone. An improved multiple harmonic balance method is used to solve the governing equations of rotations of the engine front-end accessory drive system and obtain the periodic rotational vibrations of the system accessory components. The calculation results obtained from the improved multiple harmonic balance method are verified by the results obtained from the Runge-Kutta integration method. Amplitude-frequency responses of rotational vibrations of the accessory components in the engine front-end accessory drive system are calculated using the arc-length technique based on the improved multiple harmonic balance method. Stick-slip oscillations of the tensioner arm with different values of the tensioner dry-friction torque are calculated and influences of the tensioner dry-friction on system rotational vibration amplitudes are analyzed. Variations of system vibration energies dissipated by the tensioner dry-friction at different crankshaft speeds with increases of the maximum tensioner dry-friction torque are calculated, and an optimum design of the tensioner dry-friction damping is given according to the results.