4MATIC: the intelligent all-wheel drive system - PART III

OFFICIAL PRESS RELEASE

Stuttgart/Hochgurgl, Germany/Austria, Nov 29, 2010

The current 4MATIC generation: Lighter, more compact, more efficient

Compared to the previous all-wheel drive technology, the latest generation of the 4MATIC all-wheel drive system stands out for its higher efficiency, lower weight and more compact design. These advantages over the predecessor models translate into superior traction and greater fuel economy. Depending on the particular model, this means that fuel consumption is a mere 0.2 to 0.6 litres or so more per hundred kilometres than on an equivalent vehicle with conventional drive.


The latest-generation 4MATIC only adds 50 to 70 kilograms of extra weight (depending on model) and boasts a compact design that now takes up less space. As a result, no modifications to the bodyshell are required and it does not encroach on the front-passenger footwell. What's more, the compact design helps to improve noise and vibration levels.

Transfer case integrated in 7G-TRONIC automatic transmission

The 4MATIC transfer case, featuring a planetary centre differential and a pair of bevel gears acting as a lateral output to the front axle, is integrated into the 7G-TRONIC PUS automatic transmission that always comes as standard on the 4MATIC models. The centre differential produces the 45:55 torque split between the front and rear axles that has the aforementioned positive impact on handling stability and traction. Further highlights of the powertrain include the lateral output to the front axle as well as the rear universal joint that is integrated into the power take-off's output gear. This space-optimised design enables the front axle propshaft to be run very close to the transmission without having to modify the bodyshell in any way.

The higher efficiency of the 4MATIC drive system compared to the predecessor models is largely down to the omission of the gear stage for the transfer case's power take-off as well as an improved oil supply, since the integral design means that transmission and transfer case share the same oil circuit. This sophisticated 4MATIC technology together with the weight saving result in a substantial reduction in fuel consumption.

ADAPTIVE BRAKE: state-of-the-art brake control system ensures shortest stopping distances � even in wintry road conditions

The ADAPTIVE BRAKE control system incorporates the basic anti-lock braking system (ABS), acceleration skid control (ASR) and yaw control functions. ABS and ASR record and control the driving dynamics along the vehicle's longitudinal axis, while the yaw control looks after the lateral dynamics. If ADAPTIVE BRAKE diagnoses critical driving situations, corrective braking and control of drive torque are used to maintain or restore traction and directional stability as far as is physically possible.

New additional braking functions make the ADAPTIVE BRAKE system even safer and more convenient. Hill-Start Assist prevents the vehicle from rolling in the opposite direction to that intended by the driver. The set of functions also includes brake priming: should the driver suddenly release the accelerator, the system prepares for possible panic braking by pressing the brake pads lightly against the brake discs. If the brakes are indeed applied with full force, the instantaneous build-up of pressure when the brake pedal is pressed shortens the stopping distance by a significant amount. Thanks to ADAPTIVE BRAKE's ability to produce even the smallest brake pressures with great precision, it is possible to remove the film of water which forms on the brake discs in wet conditions by gently applying the brakes for a brief time. This shortens the brakes' response time when driving in the wet, thus reducing the stopping distance even further. This function is triggered automatically once a certain number of windscreen wiper cycles has been reached and the driver has not applied the brakes in the meantime.

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