US Patent 9539993 By-wire fallback braking mode for brake-by-wire systems in vehicles

A vehicle includes a brake-by-wire system that delivers a certain amount of brake fluid pressure to wheel brakes depending upon the position of a brake pedal. A brake-by-wire fallback or backup mode of operation is also provided. When activated, this by-wire fallback mode commands a certain, known magnitude of brake pressure. The commanded amount of brake pressure can vary based on the state of a brake pedal on/off switch, and can be set regardless of brake pedal position. This provides a backup to the brake-by-wire system without necessarily requiring a mechanical push-through backup system to brake the vehicle in the event a backup mode is required.