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.

A method for diagnosing an electric brake system is disclosed. The method for diagnosing an electric brake system, which includes a reservoir, a master cylinder, a first backup flow path, a second backup flow path, a first cut valve, a second cut, a simulation device, a hydraulic pressure supply device, a first hydraulic flow path, a second hydraulic flow path, a hydraulic control unit, and an electronic control unit configured to control the hydraulic pressure supply device and the valves on the basis of hydraulic pressure information and displacement information of the brake pedal, comprising a first diagnosis mode of: closing the first cut valve and the second cut valve when the pedal effort is not provided to the brake pedal; operating the hydraulic pressure supply device to generate hydraulic pressure at the hydraulic control unit; measuring the hydraulic pressure in the first or second hydraulic circuit; and comparing the measured hydraulic pressure with a first reference pressure to diagnose abnormality of the valves.

A method for diagnosing an electric brake system is disclosed. The method for diagnosing an electric brake system, which includes a reservoir, a master cylinder, a first backup flow path, a second backup flow path, a first cut valve, a second cut, a simulation device, a hydraulic pressure supply device, a first hydraulic flow path, a second hydraulic flow path, a hydraulic control unit, and an electronic control unit configured to control the hydraulic pressure supply device and the valves on the basis of hydraulic pressure information and displacement information of the brake pedal, comprising a first diagnosis mode of: closing the first cut valve and the second cut valve when the pedal effort is not provided to the brake pedal; operating the hydraulic pressure supply device to generate hydraulic pressure at the hydraulic control unit; measuring the hydraulic pressure in the first or second hydraulic circuit; and comparing the measured hydraulic pressure with a first reference pressure to diagnose abnormality of the valves.

The invention relates to an emergency braking device comprising an actuator (2), a pressurizing circuit (3) supplying the actuator (2) via a control pressure and a discharge circuit (4), characterized in that the discharge circuit (4) comprises means (13, 14) for controlling the pressure and/or flow rate of the supply fluid of the actuator (2) during a discharge of the actuator, these control means (13, 14) being configured to define an intermediate pressure between a low pressure level and the control pressure of the actuator (2).

Am electric braking system is disclosed. The electric braking system comprising: a cylinder unit having a first piston connected to a brake pedal, a cylinder chamber with the volume varying by displacement of the first piston, and a pressing chamber with the volume varying by a pressing member, and sending an intention of braking to an electronic control unit; a reservoir storing a working fluid, a pressure applier having a second piston operating by receiving power and a pump chamber with the volume varying by displacement of the second piston, and hydraulically coupled to wheel brakes, a reservoir line connecting the cylinder chamber and the reservoir and having a reservoir valve; and a pump reservoir line connecting the pump chamber and the reservoir and having a dump valve.

A method of conducting a diagnostic test to determine leakage within a brake system includes first providing a brake system having a plunger assembly including a housing defining a bore therein. The plunger assembly includes a piston slidably disposed therein such that movement of the piston pressurizes a pressure chamber when the piston is moved in a first direction. The pressure chamber of the plunger assembly is in fluid communication with an output, and wherein the plunger assembly further includes an electrically operated linear actuator for moving the piston within the bore. The linear actuator of the plunger assembly is actuated to provide pressure at the output of the plunger assembly at a first predetermined level. The pressure at the output of the plunger assembly is held for a predetermined length of time. The method further includes determining whether conditional criteria has been met indicating a leakage within the brake system.

A method of conducting a diagnostic procedure for a braking system includes analyzing via an electronic control unit whether only a first input device is engaged or only a second input device is engaged, conducting a first diagnostic test if only the first input device is engaged, and conducting a second diagnostic test if only the second input device is engaged.

A vehicle includes a brake pedal, a master cylinder, a braking circuit with a wheel cylinder, and a brake pressure generator. A pedal feel simulator is coupled to the master cylinder through a switchable valve. An isolation valve is provided to isolate the braking circuit from the master cylinder and the simulator circuit. A controller is programmed to couple the simulator circuit to a pressure sensor positioned in the braking circuit at a designated diagnostic time during which the brake pedal is depressed to generate a brake pedal input while the vehicle is positively parked. Increased fluid pressure from the brake pedal input is observed with the sensor in the braking circuit. The controller checks whether the pressure-increase to brake pedal input relationship indicates efficacy of the simulator circuit for continued operation of brake-by-wire operation.

A vehicle includes a brake pedal, a master cylinder, a braking circuit with a wheel cylinder, and a brake pressure generator. A pedal feel simulator is coupled to the master cylinder through a switchable valve. An isolation valve is provided to isolate the braking circuit from the master cylinder and the simulator circuit. A controller is programmed to couple the simulator circuit to a pressure sensor positioned in the braking circuit at a designated diagnostic time during which the brake pedal is depressed to generate a brake pedal input while the vehicle is positively parked. Increased fluid pressure from the brake pedal input is observed with the sensor in the braking circuit. The controller checks whether the pressure-increase to brake pedal input relationship indicates efficacy of the simulator circuit for continued operation of brake-by-wire operation.

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.