To check the functionality/leak-tightness of a brake-by-wire brake system, a motor-operated brake pressure transducer is actuated. In this case, a pressure medium would flow out into a reservoir via a master brake cylinder. A diagnostic valve is therefore provided between the master brake cylinder and the reservoir, which diagnostic valve is composed of a check valve and a restrictor connected in parallel with respect to the check valve. The outflow of pressure medium is limited by the restrictor. Because the gradient of the pressure dissipation can be calculated, a measured pressure build-up can be compared with that which is to be expected, and a determination of functionality/leak-tightness can be derived from the comparison.

A vehicle includes a brake pedal, a master cylinder, a braking circuit with a wheel cylinder, and a brake pressure generator with strokable piston. A pedal feel simulator is coupled to the master cylinder through a switchable valve, the simulator providing a reaction force. An isolation valve closes to isolate the braking circuit from the master cylinder and the simulator circuit. A controller is programmed to place the simulator in fluid communication with an output of the brake pressure generator, and to stroke the piston at a designated diagnostic time. The resulting pressure increase is observed, and the controller checks whether the pressure-increase to piston-stroke relationship is within a predetermined acceptable range for continued operation of a brake-by-wire mode in which the master cylinder is coupled to the simulator circuit and decoupled from the braking circuit.

A vehicle includes a brake pedal, a master cylinder, a braking circuit with a wheel cylinder, and a brake pressure generator with strokable piston. A pedal feel simulator is coupled to the master cylinder through a switchable valve, the simulator providing a reaction force. An isolation valve closes to isolate the braking circuit from the master cylinder and the simulator circuit. A controller is programmed to place the simulator in fluid communication with an output of the brake pressure generator, and to stroke the piston at a designated diagnostic time. The resulting pressure increase is observed, and the controller checks whether the pressure-increase to piston-stroke relationship is within a predetermined acceptable range for continued operation of a brake-by-wire mode in which the master cylinder is coupled to the simulator circuit and decoupled from the braking circuit.

A leakage inspecting method of an electric brake system, which includes a master cylinder connected to a reservoir, a simulation device having one side connected to the master cylinder to provide a reaction force according to the pedal effort of the brake pedal, a simulation valve provided at a flow path connected to the master cylinder or a flow path connected to the reservoir, a hydraulic pressure supply device operated by an electrical signal of a pedal displacement sensor sensing a displacement of the brake pedal and configured to generate hydraulic pressure, and a hydraulic pressure control unit, comprising: executing an inspection mode for inspecting for a leak of the simulation valve and a sealing member provided inside a chamber of the master cylinder by providing an inspection valve at a flow path connecting the master cylinder to the reservoir, wherein the inspection mode includes: (a1) closing a cut valve provided at a flow path connecting the master cylinder to the hydraulic pressure control unit when the inspection valve is open; (b1) pressurizing a piston disposed inside the master cylinder according to the pedal effort of the brake pedal and detecting whether pressure is formed through a pressure sensor; and (c1) determining that a leak does not exist when pressure detected through the pressure sensor satisfies a preset criterion.

A system and method for performing a diagnostic on a hydraulic system in a vehicle while the vehicle is at a standstill. The method includes, by means of an electronic processor, moving a plunger at a constant rate, determining a position of the plunger, receiving a pressure of the hydraulic system from a pressure sensor, comparing the determined position and the measured pressure to a position versus pressure graph, and sending a diagnostic to a diagnostic indicator.

An electronic brake system and a method for operating the same are disclosed. The electronic brake system includes a hydraulic-pressure supply device and a hydraulic-pressure control unit. The hydraulic-pressure supply device operates a hydraulic piston using an electric signal corresponding to a displacement of a brake pedal, and thus generates hydraulic pressure. The hydraulic-pressure control unit controls hydraulic pressure of a pressure medium supplied to individual wheel cylinders. The electronic brake system controls a plurality of valves mounted to the hydraulic-pressure control unit, and thus performs a normal operation mode, an abnormal operation mode, a regenerative braking mode, and an inspection mode using the valves.

Disclosed herein are an electric brake system and an operating method thereof. The electric brake system includes a master cylinder to discharge a pressurized medium in accordance with displacement of a brake pedal, a simulation device to provide a driver with a pedal feeling, a hydraulic pressure supply device to generate a hydraulic pressure by operating a hydraulic piston in accordance with an electrical signal output in response to the displacement of the brake pedal, and a hydraulic control unit to control a hydraulic pressure of the pressurized medium supplied to each wheel cylinder. The electric brake system may perform a normal mode, an abnormal mode, and an inspection mode.

A method for monitoring a hydraulic brake system for a motor vehicle, wherein a diagnostic valve is omitted and, instead, air volume and leakage are identified by a volume balance during generation of a dynamic pressure. An associated brake system is also disclosed.

Provided is a brake apparatus, a brake control method, and a method for determining a lock abnormality in a motor capable of reducing motor drive noise at the time of a self-diagnosis of the motor regardless of a condition. A brake control method includes issuing a drive instruction to repeat ON/OFF driving a plurality of times and drive a motor in such a manner that a rotational frequency of the motor during an OFF time period does not fall to zero and a peak of the rotational frequency of the motor during an ON time period increases as the ON/OFF driving is repeated, carrying out terminal voltage detection to detect a terminal voltage of the motor at the time of the ON/OFF driving carried out by the issuing of the drive instruction, and determining a lock abnormality in the motor to determine whether there is the lock abnormality in the motor based on a characteristic of the terminal voltage during the OFF time period of the ON/OFF driving that is detected by the carrying out of the terminal voltage detection.

It is an object of the invention to provide a brake device capable of detecting a failure in each of components, by which booster control is performed, at an early stage even during vehicle running. The brake device is configured to discharge brake fluid into a communicating fluid path that connects a fluid path of a primary system and a fluid path of a secondary system, and to control a first communicating valve for restricting a flow of brake fluid from the communicating fluid path to the fluid path of the primary system and a second communicating valve for restricting a flow of brake fluid from the communicating fluid path to the fluid path of the secondary system in respective valve-closing directions, so as to check at least a state of the pump.