Industry still wary
It is hard for new braking solutions to compete against effective, well-priced hydraulic brakes. Delphi 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 had a shaky start. Pioneered by Mercedes-Benz and Robert Bosch 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.
"It had to have a hydraulic back-up, which unfortunately came into play quite often," said a senior industry executive.
The experience created mistrust and suspicion toward innovative braking solutions. As a result, 98 percent of European new cars have conventional hydraulic disc brakes.
Automakers remain cautious. A BMW spokesman declined comment on future brake technology. But last year, BMW board member Burkhard Göschel said that brake-by-wire would come to BMW and would be used first on the rear axle.
Bosch, Continental and TRW Automotive lead European brake sales. A Frost and Sullivan study estimates 2005 European advanced brakes sales at E5 billion. Globally, braking is a E17 billion segment.
Joseph Pickenhahn, TRW vice pre-sident for brake engineering, said future brake growth will be in combined braking and steering systems.
"Collision mitigation systems will dictate new requirements," he said. "We want to apply the brakes as fast as possible. It's 600 milliseconds before we get 1g braking. We want to get the 1g within 300 milliseconds."
Siemens VDO's Gombert says by-wire's all-electrical signals can link to a car's existing chassis computer.
"You can really save money by combining electronic units," he said. "The ABS [antilock brakes] and ESC [electronic stability control] are not hydraulic valve blocks, but just pieces of software."
Some have doubts about by-wire.
Krishnasami Rajagopalan, author of the Frost and Sullivan study, believes the Siemens VDO system will be "quite well-priced" but its need for a backup battery will limit use.
TRW is only monitoring developments of by-wire systems.
Bosch will focus on hydraulic brakes for the next 10 to 15 years. "Bosch is still researching electro-mechanical braking systems, but sees technical hurdles without clear solutions to overcome them," spokes-man Stephan Kraus said.
Continental said it is researching and developing by-wire braking systems, but declined further comment.
Italian brake supplier Brembo has two by-wire projects with carmakers. "Brake-by-wire will come on one part of the vehicle first," said Roberto Vavassori, business development director. "Manufacturers want to be very cautious [after] the E class."
But by-wire brakes will come, he said. "We favor small fully electric or hybrid vehicles to exploit this technology first."