The Audi S4: Dynamic Steering
Audi drive select becomes the ultimate dynamic driving system in conjunction with Audi dynamic steering. It is the perfect partner for the quattro driveline with sport differential. Its effect when combined with damping control and dynamic steering opens up a whole new dimension in safe, sporty driving.
The dynamic steering system uses a superimposed zero-play transmission to vary the effective steering ratio according to road speed. It is integrated into the steering column and combined with an electric motor. Here again, the Audi engineers have come up with a brilliant solution: the innovative axial transmission is extremely compact, light in weight and torsionally rigid. It operates without any play and is therefore extremely precise, with low friction. It can transmit very high torques and operates at a high level of efficiency.
Broader operating range: up to twice the ratio
In accordance with the vehicles road speed and the chosen Audi drive select mode, the dynamic steering system can vary its ratio by almost 100 percent. When the car is being parked, the steering is extremely direct, whereas when driving in a straight line at high motorway speeds a more indirect steering ratio and reduced power assistance help to maintain the cars outstanding directional stability.
The dynamic steering system can also correct a small to moderate angle of float as rapidly and effectively as a rally driver could ever react, by automatically turning the wheels slightly in the opposite direction. Brake applications are normally only needed if the angle is greater, and then in most cases only to exert a damping effect.
Dynamic steering furthermore intervenes in the event of understeering when the vehicle runs towards the outer edge of the corner. The steering ratio is made more indirect for a short time, meaning that the driver is unlikely to turn the wheel beyond the limit of good tire grip.
With regard to road dynamics and safety, the dynamic steering system, damping control and sport differential work closely together with the ESP. They reduce the burden on the stabilization program because the corrections take place considerably earlier via the input torque, the damping force or the steering angle. These rapid, efficient interventions avoid the need for brake applications in many cases, so that the car can be driven more dynamically and smoothly.
Braking on surfaces with different friction coefficients, so-called m-split braking, is generally a situation that is particularly difficult to master the side with more grip pulls the vehicle in its direction. The dynamic steering system resolves this problem largely on its own. Just about all the driver needs to do is turn the steering wheel in the desired direction of travel.
The equipment, data, and prices specified refer to the models offered in Germany. Subject to amendment; errors and omissions excepted.
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