Modelling of Electromechanically Actuated Active Differential Wet-Clutch Dynamics

The paper presents a lumped-parameter dynamic model of an electromechanically actuated wet clutch found in an active limited slip differential. The bond graph modelling technique is used to describe the multi-physical clutch system including the clutch actuator dynamics, the axial dynamics with the fluid film squeeze effect, the thermal dynamics, and the torque development dynamics with a multi-functional clutch friction coefficient static characteristic. Different variants of the individual subsystem models are considered, ranging from first-principle models to simplified and numerically more efficient models. The proposed models are parameterized and thoroughly validated on the basis of the experimental data collected by using an active differential and clutch test rig. The modelling results are used for the purpose of analysis of the clutch steady state and transient behaviour under various operating modes.