Borgwarner Inc.

Mark A Perlick

Dan Joseph Showalter

Roger J Wood

A method and apparatus for a four-wheel drive motor vehicle provides improved cornering by disengaging drive torque to the inside rear wheel during significant steering maneuvers. The apparatus includes a primary front wheel drive motor vehicle driveline having a center differential which provides drive energy to the primary (front) driveline and secondary (rear) driveline and a rear axle assembly having a pair of normally engaged (active) clutches which provide drive energy to the respective rear wheels. A steering angle sensor detects angular displacement of the steering column or front (steering) wheels and an associated controller disengages the clutch associated with the rear wheel on the inside of the turn as determined by the steering angle sensor.

Steering angle control of independent rear clutches in a four-wheel drive vehicle

A yaw damper for a front wheel drive vehicle provides torque transfer between the two non-driven wheels and generates a damping yaw moment in opposition to the current vehicle yaw condition. The yaw damper is passive and includes a mechanical clutch or fluid connection between the two non-driven wheels which transfer yaw correcting torque. The mechanical clutch includes first and second pluralities of interleaved friction disks which are coupled by shafts to respective non-driven wheels. A spring compresses the clutch pack and limits torque transfer between the shafts and wheels to a pre-selected maximum torque. In another embodiment, positive displacement pumps driven by each of the non-driven wheels are connected in series and transmit torque in proportion to the speed difference. In another embodiment, nested shafts include centrifugal clutches which transfer torque in proportion to vehicle speed and difference.

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Shelby Township, MI, United States of America

Mark A Perlick