Abstract: A brake system includes a pedal feel emulator and a master cylinder with a damping mechanism having a damping piston. When the emulator piston is moved from the at-rest position, fluid is displaced from the emulator through a compensation port and through a flow restrictive orifice in the damping piston to the reservoir. Flow rate of the fluid is dependent on the apply rate of the brake pedal. When the brake pedal is applied relatively slowly, sufficient flow volume will occur through the flow restrictive orifice and the damping piston will remain unmoved. As apply rates increase, a sufficient pressure differential will eventually be established across the damping piston to cause it to move. Damping piston movement compensates for rapid fluid displacement out of the variable chamber and enables a desirable pedal feel characteristic where pedal force increases relatively slowly as pedal velocity increases relatively rapidly.

Abstract: A method and apparatus is disclosed for controlling the application of a clock stopping signal in a processor to limit power consumption. The system controller receives addresses, signals indicative of primary and secondary system activity, and at least one nap timeout signal. Interrupt addresses or programmed addresses are trapped and stored as shadowed addresses. Current addresses may be compared with shadowed addresses. Matching addresses trigger a nap mode. Upon nap mode triggering, the clock stopping signal may be applied during a throttling period. Applying the clock stopping signal with programmable duty cycle during the throttling period ensures that processing necessary for the detection and servicing of primary and secondary activity can occur. A prefetch detect circuit ensures that shadowed addresses loaded in the middle of a prefetch do not trigger the clock stopping signal. Clock stopping signal is removed or inhibited when primary or secondary activity is detected or when a nap timer expires.

Abstract: An electro-hydraulic brake apply system includes an emulator that effects pedal feel simulation by allowing compliance at a selective variable rate. This provides a vehicle driver with the preferred pedal travel and feedback characteristics of a conventional master cylinder/power booster apply system. As a secondary function, the emulator is utilized to latch the modulator. This locks the modulator apply piston in place when electrical power is removed from the drive motor. Further, the emulator operates to hydraulically isolate the master cylinder from the wheel brakes during normal system operation.

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.