Audi plans electric quattro all-wheel drive

Some of Audi's future technology plans have been revealed in new technical patents.

Not all patents make it into series-production cars, but two engineering ideas — one very simple and one very complex — look set to enter production within the next few years.

The simple idea suggests using hinged flaps between the spokes of an alloy wheel. The flaps move radially over the spokes as the wheel speeds up, creating a completely flat wheel cover. 

According to Audi’s application, fully enclosed wheels not only smooth airflow at speed but also help to improve the car’s overall aerodynamic performance, thanks to changes in air pressure under the car. As the car slows, the wheel flaps open again, but the flaps are also temperature sensitive, so they can open up if the braking surfaces become too hot.

The second patent appears to show a new-generation Audi all-wheel drive system which uses an electrically driven rear axle. This is a logical progression for the traditional quattro system, combining rapid-reacting all-wheel drive and electric drive.

However, the description says Audi is seeking a patent for a software system that uses the wheel sensors to detect the point at which one of the wheels might break traction on a slippery surface. 

This can be important on hybrids, because using the regenerative braking (where the electric motor acts as a brake while also generating electricity) can cause wheels to slow too quickly and lose grip. 

Audi’s innovation appears to allow brake regeneration forces — which are usually fixed in an electric car — to vary according to the road conditions. By detecting the small differences in rotational speed between the front and rear axles, the system can also determine the friction coefficient of a road surface in real time. 

Even though this new quattro proposal is primarily designed to incorporate a hybrid transmission into a 4x4 drivetrain, it could also result in the most intelligent and quickest-reacting all-wheel drive system yet.