Siemens VDO Making a Case for In-Wheel Systems: the eCorner Project

GreenCar Congress
September 1, 2006

Siemens VDO engineers are working on plans to integrate the motor, steering, shock absorbers and brakes directly into the wheels of future cars.

The eCorner concept replaces the conventional wheel suspension with hydraulic shock absorbers, mechanical steering, hydraulic brakes and internal combustion engines with integrated in-wheel systems. Siemens VDO says that although it will naturally continue to invest in optimization of conventional internal combustion engines in an effort to completely exhaust their potential, its focus for the future is on these in-wheel systems.

Hybrid drives are only an intermediate step along the path to future propulsion solutions. We consider the electric motor to be the actual long-term drive solution for fulfilling even the most stringent emission laws of the future.
—Dr. Klaus Egger, Group Vice President of Siemens VDO Automotive

Siemens projects that wheel hub motors will be able to use up to 96% of the provided electrical energy for vehicle propulsion. This will make it much easier for automobile manufacturers to satisfy emission regulations and while simultaneously offering extremely dynamic vehicles with excellent fuel economy.

Suspension, steering and braking..While complex mechanical wheel suspension systems with oil-pressure spring elements currently ensure a comfortable ride for the passengers and permanent, reliable contact with the road, electronic circuits will play an increasingly significant role in the future.

Within eCorner, electric motors will take over the task of ensuring contact between wheel and road. With this new suspension, hydraulic steering can be eliminated, giving automakers new degrees of freedom. Each individual wheel will be able to be moved to its own specific steering angle.

When the speed is reduced, the wheel hub motors act as auxiliary brakes using a generator effect. The energy reclaimed in this manner can be used to charge the vehicle battery. Finally, in addition to the generator brakes, the electronic wedge brakes (EWB) can decelerate each wheel separately with maximum precision and enormous braking power to match the need of the driving situation.

Siemens VDO believes that the series production of its electronic wedge brake (EWB—earlier post) will be an important milestone on the way to realizing eCorner.

The greatest intermediate step toward eCorner will be an integrated electronic shock absorber and steering module expected sometime during the next decade, according to Siemens.

The combustion engine won’t have to disappear completely for the time being, the company says—it will be able to provide the necessary electrical power for flexible long-distance vehicles.