A brake system for hydraulically actuating a pair of front wheel brakes and a pair of rear wheel brakes includes a master cylinder fluidly connected to a reservoir and 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 by actuation of the brake pedal to generate brake actuating pressure at an output for hydraulically actuating a selected one of the pair of front and rear wheel brakes. A first power transmission unit is configured for actuating the selected one of the pair of front and rear wheel brakes. A second power transmission unit is configured for actuating the other one of the pair of front and rear wheel brakes. A first electronic control unit is provided for controlling at least one of the first and second power transmission units.

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.

The present disclosure relates to a method for testing a brake fluid sensor of a vehicle braking system, wherein the brake fluid sensor can indicate the fluid level in the fluid reservoir, wherein the method has the following steps: (1) Altering the fluid level in at least one region of the at least one fluid reservoir by means of at least one braking force generating device; and (2) Detecting whether the at least one brake fluid sensor emits a signal indicating the modified fluid level in the at least one region of the at least one fluid reservoir.

A hydraulic brake system for a vehicle includes a master brake cylinder, a hydraulic unit, and multiple wheel brakes. The hydraulic unit Ha at least one brake circuit for modulating the braking pressure in the wheel brakes. At least one wheel brake is paired with a bistable solenoid valve, which is looped into the corresponding fluid channel directly upstream of the paired wheel brake and which enables the braking pressure in the paired wheel brake to be modulated in a de-energized open position and locks the current braking pressure in the paired wheel brake in a de-energized closed position, wherein a volume equalization device which comprises a connectable accumulator opens into the corresponding fluid channel between the bistable solenoid valve and the paired wheel brake.

A vehicle braking device includes: an electric cylinder in which a piston driven by an electric motor slides in a cylinder to supply fluid; a hydraulic pressure output unit connected to the electric cylinder by way of a first liquid passage, the hydraulic pressure output unit pressurizing or depressurizing a hydraulic pressure in the first liquid passage and outputting the hydraulic pressure to a supply liquid passage connected to a first wheel cylinder; and a control unit that causes at least one of the electric cylinder and the hydraulic pressure output unit to generate the hydraulic pressure in the first wheel cylinder according to a relative position between the piston and the cylinder.

A vehicle braking system (20) has a primary braking unit (22) with a first pressure generating unit (34) and a first reservoir (26). The vehicle braking system (20) further has a secondary braking unit (24) with a second pressure generating unit (52) and second reservoir (70). A method of operating the vehicle braking system (20) includes actuating the pressure generating unit (34) of the primary braking unit (22) thereby pressurizing a fluid at a wheel cylinder (30) to slow or stop the vehicle. The wheel cylinder (30) is depressurized in response to an electrical signal provided to an electronic control unit (100,102). The fluid is transferred from the wheel cylinder (30) to the second reservoir (70). The fluid path (PI) between the wheel cylinder (30) and the second reservoir (70) is shorter and has less fluid resistance than the fluid path (P2) between the wheel cylinder (30) and the first reservoir (26). The present invention further comprises two braking systems. The present inventions are intended for fast pressure depressurization at quick start or launch control.

A brake pedal unit includes a housing defining a bore formed therein. An input piston is slidably disposed in the bore. The input piston is connected to a brake pedal such that engagement of the brake pedal causes movement of the input piston within the bore of the housing of the brake pedal unit. The brake pedal unit is defined to be in an at rest position when the brake pedal in not engaged causing movement of the input piston. A primary piston is slidably disposed in the bore for pressurizing a primary chamber. A primary passageway permits fluid communication between the primary chamber and the reservoir, wherein fluid flow through the primary passageway is blocked when the brake pedal unit is in the rest position. A secondary piston is slidably disposed in the bore for pressurizing a secondary chamber. A secondary passageway permits fluid communication between the secondary chamber and the reservoir, wherein fluid flow through the secondary passageway is blocked when the brake pedal unit is in the rest position.

A method of determining a homing position of a piston within a plunger assembly for a vehicle brake system at the beginning of an ignition cycle of the vehicle includes first providing a plunger assembly having a housing defining a bore therein. The plunger assembly includes a piston slidably disposed in the bore for pressurizing fluid within a pressure chamber when the piston is moved in a first direction. The plunger assembly further includes an electrically operated linear actuator for moving the piston within the bore. The method further includes providing electrical power to the linear actuator of the plunger assembly. The linear actuator is actuated to retract the piston in a second direction opposite the first direction towards an end stop. The piston engaging with the end stop is then detected.

A method is provided to check for presence of gas bubbles in an electronically slip-controllable motor vehicle brake system that includes brake circuits to which wheel brakes are connected, a pressure generator to charge the brake circuits with a brake pressure, and sensors to detect an actuating signal of the pressure generator and measure the brake pressures in the brake circuits. Disturbances are recognized by ascertaining from the signal a setpoint value for a brake pressure to be obtained and comparing it to an actual value of the brake pressure or by determining that an actual volume of the pressurizing medium displaced into the brake circuits, ascertainable from the signal, is greater than a limiting value that is determined for a setpoint value for the pressurizing-medium volume to be displaced into the brake circuits in order to generate the actual value of the brake pressure.

A method is provided for operating a motor vehicle brake system that includes an actuatable brake master cylinder, a hydraulic brake booster, and at least one brake circuit that has at least one hydraulically actuatable wheel brake and at least one hydraulic-pressure generator driven by electric motor. The method includes monitoring a state of actuation of the brake master cylinder is monitored, and, upon detecting a maximum state of actuation, activating the hydraulic-pressure generator to increase the hydraulic pressure adjusted by the brake master cylinder in the brake circuit.