Delphi Steering New 4-Wheel Drive

TROY, Mich.--Delphi Automotive Systems’ QUADRASTEER is scheduled to debut on an unnamed 2002 General Motors full-size pickup truck. It is billed as an electronic four-wheel steering system that enables full-size vehicles greater ease of maneuverability while driving or trailering at low speeds, and improved stability, handling and control at higher speeds--especially while trailering.

Current vehicles use the front two wheels to steer a vehicle. The rear wheels remain straight and actually can create some resistance. With QUADRASTEER, the rear wheels are electronically controlled according to the speed of the vehicle. At lower speeds, the rear wheels turn in the opposite direction of the front wheels improving parking maneuvers. At moderate speeds, the rear wheels remain straight or neutral. At higher speeds, the rear wheels turn in the same direction as the front wheels improving vehicle stability.

While trailering at low speeds, four-wheel steering enables the trailer to follow the true vehicle path more closely than with two-wheel steering. This makes maneuvering in city traffic and parking lots easier, according to the company. Using the rear wheels to steer also greatly improves the trailer response to steering inputs, making it easier to back a trailer into position.

While trailering at higher speeds, all four wheels steer in the same direction greatly enhancing vehicle and trailer stability. The vehicle and trailer feel more like one unit with QUADRASTEER, according to the company. Benefits to the driver include reduced trailer sway and less corrective steering requirements for external disturbances such as wind gusts, semi-truck passing and irregular road surfaces.

“Delphi is the first to design a four wheel steering system for an application that will truly benefit the consumer,” explained Paul J. Tosch, president of Delphi Saginaw Steering Systems and vice president of Delphi Automotive Systems. “And that benefit will be seen on a daily basis unlike four-wheel drive, which may only be used four or five times a year.”

Larry Tomczak, director of engineering at Delphi’s Saginaw Steering Systems division, pointed out that “QUADRASTEER also enhances stability at higher speeds when there is no trailer. Steering the rear wheels in the same direction as the front wheels at higher speeds help reduce the vehicle yaw, or rotational motion, required to accomplish a maneuver, thus helping to stabilize the vehicle response during passing, lane change or evasive maneuvers even under adverse road conditions.”

Delphi’s system enhances a full-size vehicle’s maneuverability by helping shorten the turning radius, allowing the vehicle to make tighter, more agile turns. In fact, according to the company, the smaller radius allows full-size vehicles to maneuver as adeptly as compact cars--a big plus for parking ramps, crowded parking lots or any tight situation.

Based on tests with full-size sport utility vehicles (SUVs) and pickup trucks, QUADRASTEER reduces the minimum turning circle diameter by an average of 20 percent. One full-size pickup’s turning circle diameter was reduced from 46.2 feet (14.08 meters) to 37.4 feet (11.40 meters), making it comparable to a Nissan Altima at 37.4 feet (11.40 meters) and a Saturn Coupe at 37.1 feet (11.31 meters).