DRIVELINE DYNAMICS SIMULATION AND ANALYSIS OF THE DRY CLUTCH FRICTION-INDUCED VIBRATIONS IN THE EEK FREQUENCY RANGE

Vibrations that arise during the slip phase of the clutch in the driveline of a motor vehicle yield to poor ride quality and result in discomfort and noise. The control systems in modern automated manual transmission systems couldn’t provide good improvement of vehicle longitudinal dynamics during gearshifts without a deep knowledge of the driveline model and its stiffness and damping parameters, along with the frictional conjunction between its main subparts. In this paper an original 5-degree of freedom mathematical model of the dry clutch mechanism is presented with the intention of studying the excitation in a passenger car driveline of torsional vibration by frictional actions during the slip phase of the engagement. Furthermore, the analysis aims to deepen about the coupling between pressure plate wobbling and torsional motions in order to improve the current understanding of the excitation mechanisms in the frequency region of the so-called “eek noise”, 250-500 Hz. The results of this work substantiate that enhancing of torsional motion in the characteristic frequency range of the “eek sound” occurs even regardless of the rigid wobbling motion of the pressure plate and underline the need to include the non-linear characteristic of the clutch cushion spring in the simulation of such a phenomenon