Search Results

Wet clutches are widely used in automotive systems. They are essential parts of automatic transmissions, modern All-Wheel-Drive systems or dual-clutch transmissions. Regardless of the area of application, a good knowledge of clutch friction behaviors is crucial for the clutch control system development. This paper considers two important factors of the wet clutch dynamics: coefficient of friction behavior and thermal dynamics. An Active Limited Slip Differential wet clutch with carbon fiber-based friction lining material is experimentally characterized by using a precise wet clutch setup. The characterization of the coefficient of friction behavior includes influence of clutch slip speed, applied force, and friction surface temperature. The clutch thermal dynamics is characterized based on the heat power balance law applied to the clutch separator plate with a variable heat transfer coefficient. The results of the thermal model experimental validation are presented, as well.

In order to support active limited slip differential (ALSD) modeling work, a test rig of a DC motor-actuated ALSD has been developed. The test rig is equipped with a torque servomotor that provides a precise closed-loop control of the clutch slip speed, as well as with sensors of clutch torque, and DC motor position and current. In addition to the test rig, a precise wet clutch experimental setup has been developed by using the differential hardware. The setup provides direct measurements of the clutch pack axial force, the separator plate temperature, and the press plate axial position. The paper describes the ALSD test rig and the wet clutch experimental setup, presents and analyzes characteristic experimental results, and outlines the main ALSD modeling results.