An electronic limited slip differential has been developed by Eaton Corp. (eaton.com) to provide instant traction and stability for front- and rear-wheel drive vehicles in slippery road conditions. This technology, known as "Ultra Posi," also offers a 10% fuel savings compared to standard four- and all-wheel drive systems.
Ultra Posi is located inside the transaxle and receives input from existing brake, wheel-speed, steering wheel, throttle, yaw and lateral acceleration sensors. This data ensures that each wheel is receiving sufficient torque. If slippage occurs, a hydraulic power supply transfers extra torque to the wheel with the most traction by modulating the differential anywhere from fully open to fully locked, depending on the conditions.
The Ultra Posi differential also features a 20-30% improvement in managing over-steer with less brake intervention compared to all-wheel drive vehicles, says Chris Ostrander, Eaton Torque Controls vice president and general manager.