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Understanding Audi's eAWS Active-Roll Stabilization System

The SUV has quickly become a favorite among motorists due to the practicality, versatility and imposing driving feel they offer, but getting large vehicles to handle like a sports car is a huge challenge. Not for Audi’s innovative engineers, though, who took up this challenge and developed the eAWS system.
Audi SQ7 8 photos
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The sport utility vehicle (SUV) is designed to be a practical alternative to run-of-the-mill cars, offering more cabin and storage space while also being able to perform reasonably well on paved roads and rough terrain.

Building a larger vehicle means an increase of the curb weight and a higher center of gravity, which will result in the body leaning toward the outside when cornering far more than it would in a sports car.

This means that the wheel on the outside of the corner will compress and the one on the inside will rebound, which makes the vehicle roll around its longitudinal axis.

There are passive solutions to counter this, such as torsional flexible anti-roll bars, but as they will offer the desired effect when cornering and straight-line driving, on an SUV especially they reduce ride comfort on poor quality roads or trails.

Audi managed to develop the perfect solution to dramatically improve both the SUV’s cornering ability and ride comfort using an electromechanical roll stabilization system.

Unlike conventional stabilizers that operate passively by balancing the suspension movements mechanically, the eAWS can actively control and stabilize the suspension by continually scanning its movements and intervening with pin-point accuracy when necessary.

The system contains two stabilizer halves per axle and an electric motor operating between them on both the front and rear axle. It can rotate the halves in opposite directions to each other, which generates the necessary torque to counteract the body roll.

The system is connected to control units placed on each axl,e which are part of the Electronic Chassis Platform (ECP), the brain, if you will, of the chassis.

It continuously reads parameters such as speed, ride height, roll and pitch movements, the friction coefficient of the road surface, the current driving condition such as understeer or oversteer and can make adjustments to the chassis and drivetrain within milliseconds.

A powerful onboard 48-volt electrical system provides the energy required by the eAWS and calculates the suitable actuation values for the stabilizers. In turn, the electric motors deliver their power through three-stage planetary gearboxes.

This system does not use any oil like conventional hydraulic systems and can even recuperate energy generated by the suspension and convert it to electrical energy that is stored in a lithium-ion battery placed near the rear eAWS control unit.

The Audi driving dynamics system supplies various setup options to match the driving style and road surface while continuing to increase comfort and agility.

This eAWS system provides owners of some Audi Q models increased confidence by making the car handle exceptionally well, even when attacking corners with the aggressiveness of a sports car while also offering reduced movements on rough terrain and thus providing increased ride comfort.

It was extensively tested by the German manufacturer, which last year gave the reins of the RS Q8 fitted with the eAWS to test driver Frank Stippler, two-time winner of the 24-hour race at the Nurburgring.

He managed to complete the 20.832-kilometer lap of the famed Nordschleife in just 7:42 minutes, a new lap record for a production SUV.

 
 
 
 
 

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