Multi-body dynamics analysis of power train judder oscillations considering aggregate dynamics

Abstract

Torsional oscillations in an open power train during start-up process are commonly called judder or clutch judder. Due to the rotational-translational coupling of tyres and body the longitudinal acceleration of the car passengers is, according to the appearing magnitudes, affected in a way that their driving comfort may be disturbed notably. Main subject of this paper is the simulation of judder oscillations. Additionally it provides a single-mass flywheel clutch model, which is integrated in a multi-body dynamics power train model to analyse the different mechanisms of judder. The results show, on the one hand, the massive influence of aggregate roll and stroke motions on judder vibrations, so it can be said that the clutch is not the only cause of those disturbances. On the other hand, a parameter study exposes sensitive values in the power train that have impact on those oscillations. Finally, different clutch concepts are compared with regard to judder.