Variation mechanism of the friction torque in a Cu-based wet clutch affected by operating parameters

A comprehensive thermodynamic model is proposed to investigate the variation mechanism of friction torque in a Cu-based wet clutch affected by the operating parameters, which is verified by the bench test. The results show that the variation of friction torque is composed of three stages: preparation stage A, stable growth stage B and exponential growth stage C. Moreover, increasing the relative speed can reduce the growth rate of friction torque, so as to decrease its peak value; contrarily, increasing the applied pressure can effectively offset the decline of the friction torque slope caused by the rise of relative speed. Therefore, the relative speed and applied pressure should be reasonably matched to ensure a smooth and safe clutch engagement.