What do they mean when they say a car has a brake-by-wire system. Is there actually a wire involved? – Stuart
The term brake-by-wire evolved from the aviation industry where most of the controls in the cockpit communicate with the systems involved electronically.
Because of the distances involved – hundreds of feet in some cases – and less-stringent budget constraints, aircraft manufacturers have long used remote communication through electronics to operate most control surfaces and other events. In the auto industry's search for improved efficiency, this type of control interface started to surface in high-end cars where the added cost could be more easily accepted.
The attraction was clear: replace all those hoses, lines, pumps and belts with an electronic signal.
In a traditional system, when you push the brake pedal, it activates a hydraulic system that involves a vacuum system, hydraulic pump and steel lines to each wheel. Mercedes was among the first to offer a new brake-by-wire system to replace all of that, reducing weight and complexity and improving speed and action.
Co-developed with Bosch, it involved sensors that measure the speed and force of pedal application, relaying this info to a control unit that sends the proper braking force to each wheel independently.
Since that first use, the system has become more widespread and joined by electronic power steering and electronic throttle control.