Abstract: A brake pedal unit for coupling to a brake pedal includes a housing and a pedal simulator housed within a simulation chamber formed in the housing. The pedal simulator includes a spring for providing force feedback. A first piston is mounted in the housing. The first piston is operable to generate brake actuating pressure at a first pressure output. A second piston is mounted in the housing. The first piston is operable to generate brake actuating pressure at a second pressure output. An input piston is connected to operate the pedal simulator during a normal braking mode, and wherein the input piston is coupled to actuate the first and second pistons during a manual push-though mode.

Abstract: A plunger assembly for use as a pressure source for a brake system includes a housing having first and second ports. A motor is mounted on the housing for driving an actuator. A piston is connected to the actuator. The piston is slidably mounted within the housing. The piston pressurizes a first chamber when the piston is moving in a first direction to provide fluid out of the first port. The piston pressurizes a second chamber when the piston is moving in a second direction to provide fluid out of the second port.

Abstract: A brake system includes first and second wheel brakes, a reservoir, and a brake pedal unit having a housing and a pair of output pistons slidably disposed in the housing. The output pistons generate brake actuating pressure during a manual push-through mode for actuating the first and second wheel brakes. The system further includes a plunger assembly having a housing having first and second ports, a motor driving an actuator, and a piston connected to the actuator. The piston pressurizes a first chamber when the piston is moving in a first direction to provide fluid flow out of the first port. The piston pressurizes a second chamber when the piston is moving in a second direction opposite the first direction to provide fluid flow out of the second port. The first and second ports are selectively in fluid communication with the wheel brakes.

Abstract: A vehicle brake system includes a brake pedal unit (BPU) coupled to a vehicle brake pedal and including an input piston connected to operate a pedal simulator during a normal braking mode, and coupled to actuate a pair of output pistons during a manual push through mode. The output pistons are operable to generate brake actuating pressure at first and second outputs of the BPU. A hydraulic pressure source for supplying fluid at a controlled boost pressure is included. The system further includes a hydraulic control unit (HCU) adapted to be hydraulically connected to the BPU and the hydraulic pressure source, the HCU including a slip control valve arrangement, and a switching base brake valve arrangement for switching the brake system between the normal braking mode wherein boost pressure from the pressure source is supplied to first and second vehicle brakes, and the manual push through mode wherein brake actuating pressure from the BPU is supplied to the first and second vehicle brakes.

Abstract: A vehicle brake system includes a brake pedal unit (BPU) coupled to a vehicle brake pedal and including an input piston connected to operate a pedal simulator during a normal braking mode, and coupled to actuate a pair of output pistons during a manual push through mode. The output pistons are operable to generate brake actuating pressure at first and second outputs of the BPU. A hydraulic pressure source for supplying fluid at a controlled boost pressure is included. The system further includes a hydraulic control unit (HCU) adapted to be hydraulically connected to the BPU and the hydraulic pressure source, the HCU including a slip control valve arrangement, and a switching base brake valve arrangement for switching the brake system between the normal braking mode wherein boost pressure from the pressure source is supplied to first and second vehicle brakes, and the manual push through mode wherein brake actuating pressure from the BPU is supplied to the first and second vehicle brakes.

Abstract: A plunger assembly for use as a pressure source for a brake system includes a housing having first and second ports. A motor is mounted on the housing for driving an actuator. A piston is connected to the actuator. The piston is slidably mounted within the housing. The piston pressurizes a first chamber when the piston is moving in a first direction to provide fluid out of the first port. The piston pressurizes a second chamber when the piston is moving in a second direction to provide fluid out of the second port.

Abstract: The brake system includes a pedal, a pedal simulator, and a brake pedal unit. The brake pedal unit includes an input piston connected to the brake pedal for operating the pedal simulator during a normal braking mode. The brake pedal unit further includes first and second output pistons actuated by the input piston during a manual push through mode such that the first output piston generates brake actuating pressure at a first output of the brake pedal unit, and the second output piston generates actuating pressure at a second output of the brake pedal unit. The brake system further includes a hydraulic pressure source for supplying fluid at a controlled boost pressure, and a hydraulic control unit adapted to be hydraulically connected to the brake pedal unit and the hydraulic pressure source.

Abstract: An electronically controlled boosted brake system including an isolation valve between a source of pressurized fluid and a boost valve for selectively restricting the flow of fluid from the source to the boost valve. Another feature of the brake system relates to an accumulator valve connected between the boost valve and the accumulator for controlling when the operating pressure of the accumulator is supplied to the boost valve. Yet another feature is a unique master cylinder design including at least one primary piston positioned within a housing in an overlapping relationship with portions of a pair of secondary pistons.

Abstract: A vehicle brake system includes a brake pedal unit (BPU) coupled to a vehicle brake pedal and including an input piston connected to operate a pedal simulator during a normal braking mode, and coupled to actuate a pair of output pistons during a manual push through mode. The output pistons are operable to generate brake actuating pressure at first and second outputs of the BPU. A hydraulic pressure source for supplying fluid at a controlled boost pressure is included. The system further includes a hydraulic control unit (HCU) adapted to be hydraulically connected to the BPU and the hydraulic pressure source, the HCU including a slip control valve arrangement, and a switching base brake valve arrangement for switching the brake system between the normal braking mode wherein boost pressure from the pressure source is supplied to first and second vehicle brakes, and the manual push through mode wherein brake actuating pressure from the BPU is supplied to the first and second vehicle brakes.

Abstract: A pressure balanced supply valve for use in a vehicular braking system. A housing defines a first chamber, a second chamber, a first fluid conduit for connection to a master cylinder, a second fluid conduit for connection to a hydraulic pump, and a third fluid conduit connected between the first and second fluid conduits. The second fluid conduit communicates with both the first chamber and the second chamber. A valve seat is defined in the third fluid conduit. A movable valve element is movable to a first position sealing against the valve seat to prevent fluid flow between the first and second conduits through the third conduit, and to a second position permitting fluid flow between the first and second conduit through the third conduit. The movable valve element is exposed to pressures in both the first and second chambers so as to be pressure balanced in operation.

Abstract: An electronically controlled boosted brake system including an isolation valve between a source of pressurized fluid and a boost valve for selectively restricting the flow of fluid from the source to the boost valve. Another feature of the brake system relates to an accumulator valve connected between the boost valve and the accumulator for controlling when the operating pressure of the accumulator is supplied to the boost valve. Yet another feature is a unique master cylinder design including at least one primary piston positioned within a housing in an overlapping relationship with portions of a pair of secondary pistons.

Abstract: A braking system is provided for applying pressurized hydraulic brake fluid to a plurality of vehicle brakes. The system includes a source of pressurized brake fluid, a first brake fluid circuit, and a boost valve for controlling a flow of brake fluid from the source to the first circuit. A first brake actuator is actuated by brake fluid from the first circuit and a second brake actuator operated by an application of brake fluid from the first circuit. The system further includes a second brake fluid circuit and a third brake fluid circuit. A third brake actuator is actuated by brake fluid from the second circuit. A fourth brake actuator actuated by brake fluid from the third circuit. A master cylinder includes a primary piston, a first secondary piston, and second secondary piston.

Abstract: A pressure balanced supply valve for use in a vehicular braking system. A housing defines a first chamber, a second chamber, a first fluid conduit for connection to a master cylinder, a second fluid conduit for connection to a hydraulic pump, and a third fluid conduit connected between the first and second fluid conduits. The second fluid conduit communicates with both the first chamber and the second chamber. A valve seat is defined in the third fluid conduit. A movable valve element is movable to a first position sealing against the valve seat to prevent fluid flow between the first and second conduits through the third conduit, and to a second position permitting fluid flow between the first and second conduit through the third conduit. The movable valve element is exposed to pressures in both the first and second chambers so as to be pressure balanced in operation.

Abstract: A vehicle brake system includes a master cylinder having a housing defining a bore therein. A boost piston and a primary piston are slidably disposed in the bore. The master cylinder has a boost chamber defined at least in part by the boost piston and the housing. The system further includes a source of pressurized fluid and a boost valve operable to supply fluid from the source of pressurized fluid to the boost chamber for advancing the boost piston and the primary piston in the master cylinder. According to one aspect of the invention, the boost valve is housed in the boost piston. According to another aspect of the invention, the brake system includes a switchable travel rate feature. According to yet another aspect of the invention, the master cylinder includes a jump in feature. Additional features of the invention are also described herein.

Abstract: A vehicle brake system includes a master cylinder having a housing defining a bore therein. A boost piston and a primary piston are slidably disposed in the bore. The master cylinder has a boost chamber defined at least in part by the boost piston and the housing. The system further includes a source of pressurized fluid and a boost valve operable to supply fluid from the source of pressurized fluid to the boost chamber for advancing the boost piston and the primary piston in the master cylinder. According to one aspect of the invention, the boost valve is housed in the boost piston. According to another aspect of the invention, the brake system includes a switchable travel rate feature. According to yet another aspect of the invention, the master cylinder includes a jump in feature. Additional features of the invention are also described herein.

Abstract: An electro-hydraulic control unit includes a valve body having a recess formed in a surface thereof and a circumferential wall which extends around the recess. The wall includes at least one widened portion. An electronic control Unit is mounted over the recess. The electronic control unit carries a circuit substrate which extends over the widened portion of the valve body wall such that widened portion of the valve body wall forms a heat for an electronic component carried by the circuit substrate. Additionally, components mounted on upon the circuit substrate, including a motor connector extending into the recess. A pump motor is mounted upon the valve body surface opposite from the electronic control unit. An electrical connector extends from the motor through a bore formed in the valve body and connects to the motor connector mounted upon the circuit substrate.

Abstract: A vehicular brake system having vehicle stability management includes a hydraulic master cylinder connected to wheel brakes via brake conduits. A pump generates fluid pressures and pressure control valves located between the master cylinder and the wheel brakes regulate the fluid pressures at the wheel brakes to achieve ABS and traction control. A medium pressure accumulator stores fluid pressurized by the pump which is supplied to the wheel brakes via associated control valves to achieve VSM braking control. The brake system has low power requirements because the medium pressure accumulator does not have to be filled quickly, yet the stored pressurized fluid can be released to the wheel brakes to quickly produce the braking pressures necessary for initiating most VSM applications. The pump is used to supplement the accumulator pressures to achieve full VSM control.

Abstract: A vehicle brake system having a wheel brake and first and second conduits in fluid communication with the wheel brake. A master cylinder having an outlet is in fluid communication with the first conduit for supplying pressurized fluid to the first conduit. The brake system further includes an isolation valve movable between a first position, wherein fluid is permitted to flow from the master cylinder to the wheel brake via the first conduit, and a second position, wherein fluid is prevented from flowing from the master cylinder to the wheel brake via the first conduit. The isolation valve is preferably a pilot-operated valve movable between the first and second positions by a pressure differential between the outlet of the master cylinder and the pressure in the second conduit between the boost valve and the wheel brake. A source of pressurized fluid is in fluid communication with the wheel brake via the second conduit.

Abstract: A hydraulic control unit of a vehicular brake system includes a housing having a cavity. Drive means is received in the cavity of the housing. A fluid supply source is in fluid communication with the housing. A piston slidably is disposed in the housing. The piston includes a first end and a second end wherein the second end is in contact with the drive means so that the piston moves from a bottom-dead-center position to a top-dead-center position. Biasing means is in contact with the first end of the piston so that the piston moves from a top-dead-center position to the bottom-dead-center position. A first variable-volume chamber is defined by the piston and the housing whereby fluid is transferred from the first variable-volume chamber when the piston moves from the bottom-dead-center position.

Abstract: An improved electro-hydraulic brake system having features for improving the pedal feel of the system, while further having design features which contribute to the economy of manufacture of certain components of the system. The system provides for an electrically powered normal source of pressurized hydraulic brake fluid, and a manually powered backup source of pressurized hydraulic brake fluid to the vehicle brakes in the event of failure of the normal source. During normal braking, fluid from the backup source is redirected from the vehicle brakes to a pedal simulator. The pedal simulator preferably includes arrangements of spring loaded pistons, expansion volumes, and damping orifices, together with valves selectively controlling the flow of fluid to and from the pedal simulator which provides for an improved pedal feel during vehicle braking.