Saab XWD – The Leader in All Wheel Drive Technology

Posted on 30. Jul, 2008 by Ryan in 2000-2009, Germany

Photo Credit: Saab Automobile Germany

This just in from Saab Automobile Germany, loosely translated from Babelfish.

Saab XWD – The Leader in All Wheel Drive Technology

Ultramodern all wheel system sets yardsticks with comfort, security and driving fun *
XWD technology now also in 210 HP the strong Saab 9-3 with 2,0-Liter-Turbomotor *
Gradual expansion of the all wheel offer on further engine variants in Russelsheim. *

The ultramodern Saab XWD (CROSS Wheel drive) – system sets new milestones in the all wheel technology and guarantees to the driver a maximum of control and active driving fun. All the same with which climatic conditions or on which underground, with Saab XWD are drivers and passengers sporty and above all surely on the way. The fully automatic system distributes permanently, depending upon need and driving conditions, torque between foremost and rear axle. It prevented thereby effectively over or under and keeps the car trace stable. Originally for the special requirements of the Swedish winter with snow and developed, the innovative all-wheel drive masters ice-smooth lanes owing to its thought out technology just as problem-free and reliably wet-with-rain or with leaves covered, slippery roads, as it brings the coming autumn and winter season back with itself.

Saab XWD technology starting from autumn also in the classical four-cylinder turbo

Saab extends immediately gradually for 9-3 sport sedan and sport combi its offer at petrol engine variants with the innovative drive. Starting from autumn on the road and orderable there is the XWD technology already now additionally to 280 HP (206 KW) of strong 2,8 V6 turbo also for the models with 2,0-Liter-Turbomotor - a further attractions bonus for â€žthe smaller â€œSaab aggregate. The full aluminum four-cylinder supplies 210 HP (154 KW) when 5.300 revolutions per minute and a torque of 300 Newtonmeters when 2.500 revolutions. For the XWD variants of the 2,8-Liter V6 motorizing are optionally a sport chassis with harder feathers/springs and shock absorbers, larger brake disks as well as 18 – or 19-Zoll-LeichtmetallrÃ¤dern available. And the Saab typical turbo-power can combine the customers now with all equipment versions of the 9-3 row with the XWD drive, from linear over Vector to aero.

With the XWD drive Saab has the most modern and above all the most effective in the program, which has to offer the all wheel technology in the automobile sector at present. For our customers means: ultimative-sporty driving fun with at the same time greatest possible security. â€œAnd Kjell Ake Eriksson, since 1 June of new managing directors of the Saab Germany GmbH, makes desire on more: â€žAround this singular driving feeling to make possible, we did 9-3 2.0T the first step to a still larger circle from drivers with the expansion of the XWD offer on the Saab – further models, like the 2.0t bio power, will follow starting from the coming year.

Maximum traction and driving stability starting from start

In order to ensure optimum traction when starting, the all wheel system of the newest generation has an innovative Vorabaktivierung of the rear wheels. Differently than with conventional systems torque is led to the rear axle, before slip at the front wheels develops. This â€žfirst focusing â€œensures for the fact that the driver can accelerate immediately with maximum traction gently and strong without any delay.

The Saab XWD is programmed on optimal driving stability, by working against the over or under with the ideal torque distribution. So can be transferred for example with the sharp out accelerating from curves up to almost 100 per cent of the torque to the rear wheels. With autobahn trips against it under normal conditions only five to ten per cent of the traction power to the rear wheels are transferred. This provides on the one hand for a higher driving stability and helps on the other hand to save fuel. Besides the balanced torque distribution permits a higher threshold value for the ESP interference at butterfly valve and brakes. More clearance and thus more driving fun for the active, sportily oriented drivers are the result.

Highlight of the all-wheel drive Saab XWD is the active electronic differential eLSD (electronically controlled Limited slip differential) – new fact in this market segment. eLSD can supply up to 80 per cent of the maximum torque of the rear axle to the wheel with the higher traction. Thus the differential permits more control with fast driving along curves or other driving maneuvers with sudden load change to the driver, like for example an evasive maneuver or an abrupt track switching. The very fast increase or decrease of the torque at one of the rear wheels lets the rear of the vehicle follow exactly to the direction of the front wheels. Thought out technology for safe driving fun The system is steered by its own electronic monitoring unit, which works with the controllers interlaced by engine, transmission as well as ABS and ESP.

This â€žbrain â€œof the all-wheel drive receives from more than 20 sensors of 100 signals per second, ABS and ESP enclosed, which supply the XWD with information via speed, wheel rotation, transverse acceleration, butterfly valve position, greed rate and guidance angle. The hardware of the Saab of XWD system consists of the power takeoff unit (PTU) in the front final drive, which leads a part of the engine torque over a cardan shaft to the Rear drive of modules (RDM) in the rear of the vehicle. There torque transfer DEVICE (TTD) as well as the optional electronic differential eLSD for the torque distribution between the two axles (TTD) provide, and/or between the rear wheels (eLSD).

The two systems work with multi-disk wet clutches of Haldex. With the trick at the ignition key the torque distribution of TTD is activated, as soon as the driver inserts a course. Thus scolded yourself via RDM the rear-wheel drive still before starting too. While driving the torque of the engine is distributed continual steplessly between the axles. Over a valve of the TTD becomes, depending upon need, which increases or reduces hydraulic pressure on the disks of the wet clutch, in order to connect the rear-wheel drive. According to the same principle beside the RDM the stored works eLSD, in order to distribute the torque accordingly between the rear wheels. Technique glossary to Saab XWD: ABS anti-skid system eLSD electronically controlled Limited slip differential/electronic differential ESP electronic stability program PTU power takeoff unit RDM Rear drive of modules TTD torques transfer DEVICE XWD CROSSes Wheel drive/all-wheel drive

Technology Glossary of Saab XWD:

ABS Anti-lock braking system
eLSD electronically-controlled Limited Slip Differential
ESP electronic stability program
PTU Power Take-off Unit
RDM Rear Drive Module
TTD Torque Transfer Device
XWD Cross Wheel Drive