Abstract: A vehicle braking system that primarily operates as a pure brake-by-wire system, with optional hydraulic actuation. The system includes a set of four electrically actuated drum brakes. At least two of the wheel brakes include hydraulic actuators that operate to apply the wheel brakes independent of electric control. Each of the wheel brakes is normally operated in response to a control signal generated by the vehicle's brake processor. As such, a primary brake-by-wire system is provided at all four vehicle wheels. The rear brakes are proportioned to the front brakes electrically, according to design criteria.

Abstract: A brake pedal feel emulator includes a piston that is movable against the force of a compressible elastomeric body and fluid force. The emulator supplies conventional pedal feel and travel characteristics when the primary and secondary pistons of the brake system's master cylinder are substantially movable due to isolation of the master cylinder from the wheel brakes. The fluid force is supplied by controlling the flow of fluid from behind the emulator piston through a flow restrictive orifice to a conventional fluid reservoir on the master cylinder assembly. The emulator is operable with electric or electro-hydraulically controlled braking system.

Abstract: A rotary actuated braking system includes a motor driven shaft that operates two pairs of piston pumps and an allocation valve which, in combination with a single solenoid valve, effects ABS operation of the braking system. A combination of pressure operated control valves and pressure operated release valves for each control wheel brake respond to operation of the rotary actuator and solenoid valve to effect ABS pressure release and reapply from the corresponding wheel brake. A power boosted master cylinder provides base brake operation independent of the rotary actuator effected ABS operation.

Abstract: A power brake apply system includes a master cylinder having a piston for generating fluid pressure within a braking circuit. A boost valve assembly is mounted adjacent the master cylinder and carries a slidable spool that selectively closes off a normal path of communication between a fluid reservoir and the boost chamber of the master cylinder in response to the manual actuation of the master cylinder's piston as effected through a pressurized braking circuit. After closure of communication between the reservoir and the boost chamber a power fluid supply is opened to the boost chamber to provide power assist in the actuation of the master cylinder's piston.