Russelsheim, 18. February 2008 – The Swedish automaker Saab wants to provide with the XWD four-wheel drive (Cross Wheel Drive) for more safety and sportiness. The four-wheel drive was specially designed for the 9-3 Aero and Turbo X models in conjunction with the 280 hp 2.8 V6 turbomotor developed. Sales start is still in the spring of 2008.
In advance activation of the rear ratchet
The XWD from Saab is not only a four-wheel drive, but also a driving dynamics system that makes torque use. In contrast to the ESP, which supports a vehicle via brake engagers in the track, torque-based systems stabilize a vehicle under load. So they do not brake the vehicle, but on the contrary even can cause a vehicle to be much faster for fast change curves, for example.
For Saabs XWD, the torque is distributed fully automatically and variably between front and rear axles, as needed and driving situation, to counteract purposes or excess control. When starting, a pre-activation also ensures that torque is directed to the rear roller. Thus, Saab prevents the slip on the front wheels, which can be caused by the center of gravity to the rear of the front wheels.
100 signals per second
The electronic control unit of the four-wheel drive receives more than 20 sensors 100 signals per second. They provide the XWD with information about speed, wheel revolutions, transverse acceleration, throttle position, yaw rate and steering angle. When sharp detuning from curves, almost 100 percent of the torque can be transferred to the rear axle. In the case of highway rides, on the other hand, only five to ten percent of torque are posted to the rear ride. This is supposed to ensure a high driving stability and reduce friction to save fuel.