In order to detect air in a brake master cylinder within a hydraulic power brake system, a brake master cylinder pressure on actuation of the brake master cylinder is compared with a comparison pressure which prevails in the brake master cylinder when it is air-free. For bleeding, brake fluid is conveyed with a power brake pressure generator through the in this case non-actuated brake master cylinder into a pressureless brake fluid reservoir, where air escapes from the brake fluid.

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.

A piston-cylinder unit includes a piston delimiting at least one working chamber, in which a first seal for sealing at least one first working chamber is arranged either between the piston and cylinder or between a plunger connected to the piston and the cylinder. A second seal is arranged between the first seal and the first working chamber, and the piston-cylinder unit further includes a first channel arranged in the wall of the cylinder or in the piston, which joins the first seal and the second seal in the inner chamber of the cylinder. The first channel and/or a hydraulic line connected thereto may have a throttle device and/or a valve device. An electronic control and regulating device may have a diagnosis or monitoring function for a possible defect or failure of a seal. Multiple hydraulic devices may have such piston-cylinder units and respective control and such regulating devices.

A braking system for vehicles with collapsible actuation pedal may have an operating pedal operatively connected to a hydraulic pump having a delivery circuit fluidically connected to an accumulator device. The delivery circuit may have a hydraulic branch equipped with at least one normally closed control valve. The control valve may be connected to a control actuator which commands its opening when an impact or accident is detected by an appropriate detector or the control valve may be calibrated to open automatically when a limit pressure and/or flow rate value is reached in the hydraulic branch following the lowering of the actuation pedal.

A valve arrangement is inserted between a master brake cylinder and a reservoir in a housing of an electrohydraulic motor vehicle brake system which can be activated both by a vehicle driver and independently of the vehicle driver. The valve arrangement can be acted on by a volume flow which can be conveyed by a linear actuator in the direction of a pedal travel simulator, the working chamber of the pedal travel simulator being connected to the master brake cylinder, wherein, for the purpose of simplified construction and actuation, the valve arrangement has a hydraulically actuable non-return valve and a fixed diaphragm arranged parallel to the non-return valve. The non-return valve is arranged together with the fixed diaphragm in a valve carrier which is fastened to a closure plug which closes the housing of the motor vehicle brake system.

The present disclosure provides an electronic hydraulic brake system that can appropriately provide redundancy braking force, that is, an electronic hydraulic brake system that provides a so-called redundancy function, in the situation in which a driver does not drive or gives less attention to driving such as autonomous driving or smart cruise control and a main braking device malfunctions.

A brake system may include an actuation device, in particular a brake pedal; a first piston-cylinder unit with two pistons, in particular an auxiliary piston and a second piston, in order to supply brake circuits with a pressure medium via a valve device, wherein one of the pistons, in particular the auxiliary piston, can be actuated by means of the actuation device; a second piston-cylinder unit comprising an electric motor-powered drive, a transmission, and at least one piston in order to supply pressure medium to at least one of the brake circuits via a valve device; and a motor pump unit with a valve device in order to supply pressure medium to the brake circuits. The brake system may further include a hydraulic travel simulator which is connected to a pressure or working chamber of the first piston-cylinder unit.

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.

According to at least one embodiment, the present disclosure provides a method for determining failure of a solenoid valve in a brake system, the method comprising: a first valve operation process of opening a backup valve that controls opening and closing of a flow path disposed between a master cylinder and a pedal cylinder and opening and closing a plurality of valves other than the backup valve in a preset manner; a first determination process of moving a piston disposed in a master cylinder to a preset first position and determining whether the backup valve is in a failure state using a pressure sensor; a second valve operation process of closing a mixing valve that controls opening and closing of a flow path disposed between a front wheel circuit and a rear wheel circuit, and opening and closing the plurality of valves other than the mixing valve in a preset manner; and a second determination process of moving the piston disposed in the master cylinder to a preset second position and determining whether the mixing valve is in a failure state using a pressure sensor.