Highly Responsive Mechatronic Differential for Maximizing Safety and Driver Benefits of Adaptive Control Strategies

Sophisticated AWD technologies start to significantly penetrate the passenger car and crossover SUV market segments, aiming to enhance safety and fun-to-drive, rather than only focusing on the traction characteristics of the vehicle. This paper introduces a new active differential concept, which takes advantage simultaneously of a very comprehensive vehicle dynamics control software strategy and of advanced hardware capable to provide outstanding torque modulation characteristics. The differential assembly developed by Timken Automotive consists of magnetic particle clutches, mounted in a quasi-static torque split arrangement with planetary gear sets. This new mechatronic module offers simultaneously good power and torque density, which makes it suitable in particular for front wheel drive based vehicle platforms converted to all wheel drive configurations. A major advantage is the fact that the torque transfer characteristic does not depend on the input-output relative speed. Also, the differential actuation is purely electrical, allowing a high flexibility for the control algorithms. The paper presents a summary of the mechatronic module development process, its integration in the vehicle demonstrator and the test results validating its superior performance.