Auto Service World
News   June 11, 2002   by Auto Service World

Enhanced Four Wheel Steering System To Be Offered On 2003 Light Trucks

Delphi Corporation has been awarded two major new contracts for the next generation of Quadrasteer called Quadrasteer ES for Enhanced Stability.
These high volume programs represent sales revenue totaling more than $300 million annually.
Delphi debuted the first ever by-wire four-wheel steering system called Quadrasteer last year on the GMC Sierra Denali. Quadrasteer is available on several other GM trucks including the 2002 GMC Sierra and Chevy Silverado 1/2- ton, extended cab short box trucks. In addition, Quadrasteer will be available on 2003 Chevrolet Silverado and GMC Sierra 1500HD short box crew cabs, and Chevrolet Suburban and GMC Yukon XL 3/4-ton full-size sport utility vehicles.
In addition to steering the rear of the vehicle based on a predetermined set of algorithms (mathematical formulas) that account for vehicle speed and the driver’s steering wheel position, Quadrasteer ES continuously adjusts the angle of the rear wheels to accommodate for various road conditions and vehicle yaw, or rotational motion. By responding in milliseconds to changes in the road surface and vehicle state this active rear steering provides a new level of predictive stability in directional control.
A full size truck with Quadrasteer can turn as tightly as a compact car. In fact, the GMC Sierra Denali’s turn circle diameter with Quadrasteer is reduced by nearly 20%, from 46.2 feet down to 37.4 feet, which is the same as a Saturn Coupe. Quadrasteer ES will also give the same added control to full-size vehicle drivers that trailer. During low-speed towing maneuvers, the trailer follows the true vehicle path much more closely than with two-wheel steering. When backing a trailer, rear wheel steering greatly improves the trailer response to steering inputs, making it easier to place the trailer into position into a boat launch or campsite. At higher speeds stability is significantly enhanced when pulling a trailer. The rear steering increases stability, reduces trailer sway and reduces driver corrective steering to external disturbances such as wind gusts, semi- truck passing and irregular road surfaces.