Abstract: A diagnostic method to identify a leak in simulator valve in a vehicle brake system includes the steps of: (1) providing a simulator partially filled with a pressure medium and a de-energized simulator valve; (2) energizing a pumping valve, a secondary three-way valve, and a plurality of apply valves; (3) applying and retracting a plunger in a plunger assembly at least two cycles so that a predetermined pressure is achieved; (3) holding a plunger in position within the plunger assembly while maintaining a replenishing check valve in a closed/de-energized position and energizing the simulator valve; (4) obtaining a measured master cylinder secondary pressure decay; (5) comparing the measured master cylinder secondary pressure decay to a predetermined pressure decay value; and (7) identifying a leak in the simulator valve if the measured master cylinder secondary pressure decay does not match the predetermined master cylinder secondary pressure decay.

Abstract: A testing method includes the steps of: (1) providing a negative pressure generator; (2) generating a negative pressure in a fluid passageway and a chamber which are in fluid communication with a guiding section of a fluid reservoir wherein a second sensing element is affixed to a guiding section of the fluid reservoir; (3) transferring a fluid flow stream from the guiding section to the chamber via the fluid passageway and drawing a float having a first sensing element from an upper position to a lower position within the guiding section; (4) generating a signal via the first and second sensing elements as the float moves relative to the second sensing element within the guiding section; and (5) transmitting a signal to at least one of a control unit or a graphical user display.

Abstract: A brake system with a wheel brake has a fluid reservoir and a valve assembly in fluid communication with the reservoir via a first conduit. The valve assembly is in fluid communication with the wheel brake via a second conduit. The valve assembly includes a bypass valve which only permits fluid flow from the first conduit to the second conduit when the fluid pressure within the first conduit is above a predetermined pressure level above atmospheric pressure. The valve assembly further includes a check valve in a parallel path arrangement relative to the bypass valve such that the check valve permits fluid flow from the second conduit to the first conduit, and prevents fluid flow from the first conduit to the second conduit. The brake system further includes a first source of pressurized fluid providing fluid pressure for actuating the wheel brake, wherein the first source of pressurized fluid is selectively in fluid communication with the second conduit.

Abstract: The invention relates to an electrohydraulic brake unit (10) for a motor vehicle, comprising a pressure source (36) designed as an actuator (30), at least one brake piston (70, 80), and a brake circuit (38), which connects the pressure source (36) and the at least one brake piston (70, 80) to one another, wherein the pressure source (36), the at least one brake piston (70, 80) and the brake circuit (38) are arranged in a wheel brake. The invention moreover relates to a vehicle having such an electrohydraulic brake unit (10) and a method for activating the electrohydraulic brake unit (10).

Abstract: A brake system for actuating at least one wheel brake includes a reservoir and a master cylinder operable to provide a brake signal responsive to actuation of a brake pedal connected thereto. The master cylinder is selectively operable during a manual push-through mode to generate brake actuating pressure to at least one output for hydraulically actuating at least one wheel brake. A power transmission unit is configured for actuating at least one of the wheel brakes in a non-failure normal braking mode. A secondary braking module is configured for selectively providing hydraulic fluid to each of the wheel brakes in an enhanced braking mode. The secondary braking module includes a pump motor driving at least one pump unit. Each pump unit is operatively connected to a fluid accumulator associated with the correlated wheel brake for selectively varying an amount of hydraulic fluid provided to the wheel brake.

Abstract: A connection for delivering fluid to a brake system housing having a cavity includes a fluid reservoir having a port extending along a centerline and configured to be received in the cavity. A collar extends around the port. A grommet extends around the port and is received in the cavity for forming a fluid-tight seal between the port and the brake system housing. The grommet includes a flange extending radially to an outermost surface positioned radially inside the collar.

Abstract: A diagnostic method to identify a leak in a three-way valve for a vehicle brake system having a remote master cylinder which includes the steps of: (1) providing a pedal simulator having pressure medium; (2) de-energizing a secondary three-way valve; (3) retracting a dual acting plunger to the home position to drop the pressure in the boost circuit to zero while also monitoring the pressure at the output of a fluid separator via a secondary master cylinder pressure sensor; (4) determining a rate of pressure reduction at the output of a fluid separator via a secondary master cylinder pressure sensor; and (5) identifying a leak in at least one of a primary three-way valve and the secondary three way valve if the rate of pressure reduction is equal to or higher than a pre-determined rate.

Abstract: An electrohydraulic vehicle braking system is provided, comprising an electrically controllable first hydraulic pressure generator and an electrically controllable second hydraulic pressure generator. The braking system further comprises a first valve device for each wheel brake, having at least one first valve, wherein in an electrically uncontrolled state the first valve device separates its associated wheel brake from an output of the first hydraulic pressure generator, and in an electrically controlled state connects it to the output of the first hydraulic pressure generator. In addition, a second valve device for each wheel brake is provided, having a second valve between an output of the second hydraulic pressure generator and its associated wheel brake, as well as a third valve between this wheel brake and a first hydraulic fluid reservoir. The first valve device and the second valve device are arranged in parallel to one another.

Abstract: A diagnostic method to identify a leak in simulator valve in a vehicle brake system includes the steps of: (1) providing a simulator partially filled with a pressure medium and a de-energized simulator valve; (2) energizing a pumping valve, a secondary three-way valve, and a plurality of apply valves; (3) applying and retracting a plunger in a plunger assembly at least two cycles so that a predetermined pressure is achieved; (3) holding a plunger in position within the plunger assembly while maintaining a replenishing check valve in a closed/de-energized position and energizing the simulator valve; (4) obtaining a measured master cylinder secondary pressure decay; (5) comparing the measured master cylinder secondary pressure decay to a predetermined pressure decay value; and (7) identifying a leak in the simulator valve if the measured master cylinder secondary pressure decay does not match the predetermined master cylinder secondary pressure decay.

Abstract: A diagnostic method to identify a leak in simulator valve in a vehicle brake system includes the steps of: (1) providing a simulator partially filled with a pressure medium and a de-energized simulator valve; (2) energizing a pumping valve, a secondary three-way valve, and a plurality of apply valves; (3) applying and retracting a plunger in a plunger assembly at least two cycles so that a predetermined pressure is achieved; (3) holding a plunger in position within the plunger assembly while maintaining a replenishing check valve in a closed/de-energized position and energizing the simulator valve; (4) obtaining a measured master cylinder secondary pressure decay; (5) comparing the measured master cylinder secondary pressure decay to a predetermined pressure decay value; and (7) identifying a leak in the simulator valve if the measured master cylinder secondary pressure decay does not match the predetermined master cylinder secondary pressure decay.

Abstract: A diagnostic method to identify a leak in a simulator valve for a vehicle brake system comprising the steps of: (1) energizing a secondary three-way valve, a pumping valve, a simulator test valve, and a plurality of apply valves in order to maintain a pressure medium from a plunger assembly within a boost circuit; (2) applying a plunger in the plunger assembly to a predetermined pressure level; (3) holding the plunger in position within the plunger assembly; and (4) identifying a leak in a simulator valve via a signal from an ECU to a vehicle user interface if the pressure in the boost circuit deteriorates at or more than a pre-determined rate.

Abstract: A brake system has a wheel brake and is operable under a non-failure normal braking mode and a manual push-through mode. The system includes a master cylinder operable by a brake pedal during a manual push-through mode to provide fluid flow at an output for actuating the wheel brake. A first source of pressurized fluid provides fluid pressure for actuating the wheel brake under a normal braking mode. A secondary brake module includes a plunger assembly for generating brake actuating pressure for actuating the wheel brake under the manual push-through mode.

Abstract: A brake system with a wheel brake has a fluid reservoir and a valve assembly in fluid communication with the reservoir via a first conduit. The valve assembly is in fluid communication with the wheel brake via a second conduit. The valve assembly includes a bypass valve which only permits fluid flow from the first conduit to the second conduit when the fluid pressure within the first conduit is above a predetermined pressure level above atmospheric pressure. The valve assembly further includes a check valve in a parallel path arrangement relative to the bypass valve such that the check valve permits fluid flow from the second conduit to the first conduit, and prevents fluid flow from the first conduit to the second conduit. The brake system further includes a first source of pressurized fluid providing fluid pressure for actuating the wheel brake, wherein the first source of pressurized fluid is selectively in fluid communication with the second conduit.

Abstract: The invention relates to an improved plunger assembly for a vehicle brake system. The plunger assembly is operable as a pressure source to control brake fluid pressure supplied to one or more wheel brakes. The plunger assembly comprises a housing defining a cylinder; a reversible motor supported by the housing and having a rotor; and a linear actuator such as a ball screw/nut mechanism driven by the motor. A plunger head is mounted in the cylinder and driven by the linear actuator in first and second opposite directions. Improvements include a linear actuator rotationally supported on the housing by a bearing to actuate the plunger head connection to a ball screw.

Abstract: A brake system has a wheel brake and is operable under a non-failure normal braking mode and a manual push-through mode. The system includes a master cylinder operable by a brake pedal during a manual push-through mode to provide fluid flow at an output for actuating the wheel brake. A first source of pressurized fluid provides fluid pressure for actuating the wheel brake under a normal braking mode. A second source of pressurized fluid generates brake actuating pressure for actuating the wheel brake under the manual push-through mode.

Abstract: The invention relates to an improved plunger assembly for a vehicle brake system. The plunger assembly is operable as a pressure source to control brake fluid pressure supplied to one or more wheel brakes. The plunger assembly comprises a housing defining a cylinder; a reversible motor supported by the housing and having a rotor; and a linear actuator such as a ball screw/nut mechanism driven by the motor. A plunger head is mounted in the cylinder and driven by the linear actuator in first and second opposite directions. Improvements include the plunger assembly engage at least one seal that defines a portion of a pressurized chamber. An end cap covers the projecting end of the cylinder and is secured to the housing to define a fluid passageway between the end of the cylinder and at least one fluid passageway provided in the housing block.

Abstract: A diagnostic method to identify a leak in a three-way valve for a vehicle brake system having a remote master cylinder which includes the steps of: (1) providing a pedal simulator having pressure medium; (2) de-energizing a secondary three-way valve; (3) retracting a dual acting plunger to the home position to drop the pressure in the boost circuit to zero while also monitoring the pressure at the output of a fluid separator via a secondary master cylinder pressure sensor; (4) determining a rate of pressure reduction at the output of a fluid separator via a secondary master cylinder pressure sensor; and (5) identifying a leak in at least one of a primary three-way valve and the secondary three way valve if the rate of pressure reduction is equal to or higher than a pre-determined rate.

Abstract: A diagnostic method to identify a leak in a simulator valve for a vehicle brake system comprising the steps of: (1) energizing a secondary three-way valve, a pumping valve, a simulator test valve, and a plurality of apply valves in order to maintain a pressure medium from a plunger assembly within a boost circuit; (2) applying a plunger in the plunger assembly to a predetermined pressure level; (3) holding the plunger in position within the plunger assembly; and (4) identifying a leak in a simulator valve via a signal from an ECU to a vehicle user interface if the pressure in the boost circuit deteriorates at or more than a pre-determined rate.

Abstract: A diagnostic method to identify a leak in simulator valve in a vehicle brake system includes the steps of: (1) providing a simulator partially filled with a pressure medium and a de-energized simulator valve; (2) energizing a pumping valve, a secondary three-way valve, and a plurality of apply valves; (3) applying and retracting a plunger in a plunger assembly at least two cycles so that a predetermined pressure is achieved; (3) holding a plunger in position within the plunger assembly while maintaining a replenishing check valve in a closed/de-energized position and energizing the simulator valve; (4) obtaining a measured master cylinder secondary pressure decay; (5) comparing the measured master cylinder secondary pressure decay to a predetermined pressure decay value; and (7) identifying a leak in the simulator valve if the measured master cylinder secondary pressure decay does not match the predetermined master cylinder secondary pressure decay.

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 a motor driving an actuator, and a piston connected to the actuator. The piston pressurizes a chamber when the piston is moving in a first direction to provide fluid flow out of a first port and through a pair of parallel valves. 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 a second port. The first and second ports are selectively in fluid communication with the wheel brakes.