A new advance could revive brake-by-wire technology, which has been stalled since global automakers decided not to adopt 42-volt electrical systems.
Siemens VDO is developing a system that addresses a technical obstacle of by-wire brakes: providing sufficient power to make the caliper clamp hard enough on the rotor to stop the car.
The developers of early by-wire brakes anticipated that automakers would move to 42-volt in-car electrical systems from 12-volt systems to provide enough power for effective clamping forces. But carmakers decided to avoid the cost and complexity of 42 volts.
Why the wedge?
The Siemens VDO 12-volt prototype uses metal wedges in the brake system that use the car's momentum to mechanically amplify clamping forces.
"We are confident we will launch a complete brake-by-wire system in a premium car before the end of the decade," said Bernd Gombert, Siemens VDO's chief technology officer of body and chassis electronics.
He said Siemens VDO's system will cost no more than a hydraulic system, will perform better and will save fuel.
It is difficult for new braking technology to compete against hydraulic brakes. Delphi Corp. just found its first customer for a hydraulic system that doubles braking forces in a small package. Delphi didn't name the customer.
By-wire brakes suffered a shaky start. Pioneered by Mercedes-Benz and Robert Bosch GmbH on the E class in 2002, the complex system was recalled twice within a year. In addition, the by-wire brakes provided few noticeable customer benefits.