by Rick Smith
Many new technological innovations are being added to GM vehicles in 2002. GM is continuing its technology lead as they have in the past, with fuel injection in the fifties and fiber-optic technology in the seventies.
In addition to the XM-ready radio in some Cadillacs, there is the:
HUD - Head up display in CorvettesQuadraSteer - four-wheel steering in the GMC Sierra Denali
2002 Corvette Head Up display
This Head-Up Display system will be standard on the Corvette Z06 in 2002. This display technology projects vehicle speed and other information on the windshield, in digital format, ahead of the steering wheel. This enables you to keep your eyes on the road and still know your vehicle speed. From my personal experience driving the Corvette Z06 (not initially realizing what that odd reflection was) took a few minutes to become used to it.
After driving on the road awhile, it is one of those automotive technology features that become second nature and part of your normal driving experience. Only when you switch vehicles do you THEN notice that it's missing and also wish it were still there. This characteristic is similar to "tilt and telescope" steering wheels that were quite popular in the pre-airbag era. Once you adjusted your wheel to your desired setting, you didn't give any more thought. However if you drove a vehicle without this feature, THEN you began to miss it. As a side note, telescoping wheels with airbags are beginning to make a comeback, after being gone for nearly a decade.
The Head-Up Display (HUD) is an option on Corvette Coupes and Corvette Convertibles and standard on the Corvette Z06, the quickest production Corvette ever.
The Quadrasteer four-wheel-steering system will be available in late 2001 on the GMC Sierra Denali full-size pickups. This innovative technology, being offered for the first time in a full-sized truck, makes driving safer, easier and more convenient. This electromechanical system can turn the Sierra Denali's rear wheels up to 12 degrees, in relation to the front wheels. This results in excellent low-speed maneuverability and high-speed stability.
To utilize this technology, you choose from three "driving modes" using a small control located on the instrument panel. These three modes are:
2WS - conventional two wheel steering 4WS - four wheel steering 4WS Tow - four wheel steering in narrow (walled) environments
Four wheel steering works by modifying the angle of the rear wheels based on the steering wheel position, vehicle speed and "driving mode", using digital technology. The steering angle is determined by a steering wheel position sensor. This positional data is read by a microprocessor controller that determines the appropriate rear-wheel angle, based on this input and the vehicle speed. This microprocessor then controls an electric motor, which actually drives the rear steering "rack" through a planetary gearset. If system failure is detected, the Quadrasteer's fail-safe mechanism reverts back to normal two-wheel steering.
When I recently looked at this technology on a 2002 GMC Sierra Denali, I noticed the simplicity of the design. Consisting of all electronics and a motor, it had none of the complex, hydraulic-based technology that caused problems in past with four wheel steering systems.
Since the rear wheels can now turn in the opposite direction of the front wheels, the Quadrasteer technology helps the GMC Sierra make tighter turns when cornering and parking. Making a U-turn on a two lane road is also much easier. The Sierra Denalis's turning diameter is reduced by 21 percent, from 46.2 ft. to 37.4 ft. To put it another way, making a U-turn with this massive truck was about the same as turning in a BMW M3 performance coupe (at slow speeds).
At higher speeds, the microprocessor controller begins to turn the rear wheels in the same direction as the front wheels, which reduces the vehicle's "yaw". This dramatically improves stability during lane changes or when being passed by a large truck.
Quadrasteer can also help you when trailering, because you can now change lanes with less trailer sway. This technology also makes it easier to back into a boat launch or park a camper.
4WS Tow mode reduces the amount of rear-wheel steer at lower speeds, in case you park too close to a wall with a trailer. This mode also increases rear wheel steer at higher speeds to provide even more stability than 4WS mode.
Since greater tire clearance is necessary when the rear wheels can be steered, Quadrasteer-equipped Sierra Denalis have larger flared composite rear fenders, using a reaction injection molding process. This type of construction resists dents and corrosion.
Quadrasteer will also be offered as a regular production option in early 2002 on other properly equipped GMC Sierra widesides and Chevy Silverado fleetside pickups.
Dated: November 25, 2001