The pressure sensor functions as a first detection portion for detecting hydraulic pressure set according to operation of a brake pedal. The control unit detects the hydraulic pressure acting on the second piston portion through the pipe. The control unit controls differential pressure in the detected hydraulic pressure to a target value set according to vehicle speed.

Provided is a brake control apparatus and a brake system capable of improving reliability of a performance of holding a hydraulic pressure in a wheel cylinder. A brake control apparatus includes a first valve provided in a first oil passage connecting a hydraulic source configured to supply brake fluid to a wheel cylinder and the wheel cylinder to each other, a return flow oil passage connected to the first oil passage between the hydraulic source and the first valve and configured to return the brake fluid supplied from the hydraulic source to a low-pressure portion, a pressure adjustment valve provided in the return flow oil passage and configured to adjust a brake hydraulic pressure in the first oil passage, and a hydraulic holding portion configured to hold a hydraulic pressure in the wheel cylinder set by a brake hydraulic pressure supplied from the hydraulic source to the wheel cylinder by activating the pressure adjustment valve and the first valve in respective valve-closing directions.

Wheel brakes of one vehicle axle of a dual-circuit hydraulic-power vehicle brake system for an electric or hybrid vehicle are connected to one brake circuit. Brake pressure is applied by a power brake-pressure generator to the two brake circuits with a time offset. It is thereby possible to compensate for a deceleration effect of an electric motor of the vehicle, which is operated as a generator during a braking.

A brake system for hydraulically actuating a pair of front wheel brakes and a pair of rear wheel brakes includes 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 in a manual push-through mode. First and second power transmission units are in fluid communication with the reservoir and selected front and rear wheel brakes. An electronic control unit selectively controls at least one of the first and second power transmission units. First and second two-position three-way valves are each hydraulically connected with a respective power transmission unit, the master cylinder, and a respective front wheel brake. The first and second two-position three-way valves are configured to place the master cylinder in push-through fluid-supplying connection with at least a corresponding one of the pair of front wheel brakes.

A method for operating a braking system, having a front and rear axle, the braking system including: a brake booster having a brake input element, coupled to an actuating travel sensor for providing a signal of a braking input; a brake master cylinder coupled to the brake booster coupled to a brake medium reservoir; fluid lines, in fluidic communication with the brake master cylinder and the brake medium reservoir, and with braking devices of the wheels via a system of valves, each of the wheels being coupled to a generator generating a braking torque, the method including: generating a hydraulic free travel with the valves and controlling valves with a control unit, a hydraulic pressure build-up for decelerating a wheel speed being prevented by generating free travel during actuation of the brake input element; and generating a regenerative braking torque for decelerating the wheel speed, based on the braking input.

A master cylinder generates master cylinder pressures in response to a brake operation by a driver on a brake pedal. A power hydraulic pressure generation device includes a pressure pump and an accumulator, and the accumulator accumulates an accumulator pressure increased by the pressure pump. A hydraulic pressure control valve device includes holding valves, pressure decreasing valves, and master cut valves for carrying out transmission of the master cylinder pressures from the master cylinder or the accumulator pressure from the accumulator. A stroke simulator is connected to a master pressure pipe via a simulator cut valve. The normally-open master cut valves and the normally-closed simulator cut valve for carrying out transmission of the master cylinder pressures mechanically generated by the master cylinder are backed up with backup electric power so that the operations continue even in the event of a change in state of electric power supply.

A method for adjusting a zero position of a brake pedal of a brake system of a motor vehicle. A separating valve arranged at least between a main brake cylinder and the respective wheel brakes of the brake system is opened in order to reduce a volume of the brake fluid in a secondary circuit of the brake system. At least one separating valve is then closed again after the volume of the brake fluid of the secondary circuit has been reduced by the predetermined volume amount, and the brake pedal is moved to a new zero position.

A hydraulic brake system includes two brake circuits, a tandem master brake cylinder which is connected to the two brake circuits and includes a float piston, and a means for adjusting a position of the float piston, wherein a defined distribution of brake power between the two brake circuits is commensurate with the position of the float piston.

A brake control device adjusts a hydraulic pressure in a wheel cylinder in response to an operation amount of a brake operation member, and includes a pressure adjustment unit that includes an electric pump and a pressure adjustment valve and adjusts hydraulic pressure in a pressure adjustment fluid path between the electric pump and the pressure adjustment valve, and a controller that controls the electric pump and the pressure adjustment valve. The controller calculates an operation speed equivalent amount based on the operation amount, calculates a target rotation speed based on the operation speed equivalent amount, and controls the electric pump such that an actual rotation speed of the electric pump approaches the target rotation speed.

The present invention obtains a hydraulic pressure control unit capable of appropriately detecting abnormality in a hydraulic pressure control unit.

In a hydraulic pressure control unit (5) according to the present invention, a controller (52) includes a diagnosis section that executes a diagnostic mode to diagnose presence or absence of abnormality in the hydraulic pressure control mechanism (51) on the basis of a current fluctuation of a motor (35) in a state where a pump (34) is driven by the motor (35).