A control device and method for executing a holding function using a hydraulic braking system of a vehicle including building up an initial holding pressure in at least one wheel brake cylinder using at least one brake pressure buildup device and closing at least one shutoff valve situated between the at least one wheel brake cylinder and the at least one brake pressure buildup device, a new holding pressure being built up in the wheel brake cylinder, in that an intermediate pressure less than the new holding pressure is built up between the shutoff valve and the brake pressure buildup device using the brake pressure buildup device, the shutoff valve is opened upon the presence of the intermediate pressure between the shutoff valve and the brake pressure buildup device, and brake fluid is transferred using the brake pressure buildup device through the open shutoff valve into the wheel brake cylinder.

A piston pump assembly for a hydraulic power vehicle braking system including an electric motor, a planetary gear set, a helical gear, and a piston which is displaceable in a cylinder. To prevent the piston from rotating in the cylinder, cylinder pins are situated in grooves at an inner side of the cylinder and engage with the recesses in a flange of the piston. Due to reshaping, the grooves are closed at one end, so that the cylinder pins are axially secured.

A vehicle braking system includes a brake pedal, a master cylinder, and an electronically-controlled booster having an input member and an output member adapted to provide an input force to the master cylinder that combines a driver-supplied input force and a boost force provided by the electronically-controlled booster. A wheel cylinder is fluidly coupled to an outlet of the master cylinder and operable to provide a wheel braking force proportional to the input force to the master cylinder. A pump is operable to pump fluid toward the wheel cylinder to provide an assisting wheel braking force. A controller is programmed to trigger a hydraulic braking assist routine in which the pump is activated to provide the assisting wheel braking force. The controller is programmed to reduce the boost force provided by the electronically-controlled booster during the hydraulic braking assist routine.

An actuating unit for a brake system, comprises a pedal connection element that charges a booster piston with an actuating force. An elastically deformable reaction disk, absorbs the actuating and boosting forces of the booster and releases the sum of said forces to a working piston. An electrically controllable pressure supply device outputs pressure which acts upon the booster piston. The actuating unit further comprises an extension arm for detecting the differential path between the pedal connection element and the booster piston and a sensor device that detects the differential path. An electronic control unit receives the signals from the sensor device and uses said signals for controlling the pressure supply device. Differential path information is transported by the extension arm to a location near the sensor device that is radially and axially offset by the reaction disk.

A vehicle braking system includes a brake pedal, a master cylinder, and an electronically-controlled booster having an input member and an output member adapted to provide an input force to the master cylinder that combines a driver-supplied input force and a boost force provided by the electronically-controlled booster. A wheel cylinder is fluidly coupled to an outlet of the master cylinder and operable to provide a wheel braking force proportional to the input force to the master cylinder. A pump is operable to pump fluid toward the wheel cylinder to provide an assisting wheel braking force. A controller is programmed to trigger a hydraulic braking assist routine in which the pump is activated to provide the assisting wheel braking force. The controller is programmed to reduce the boost force provided by the electronically-controlled booster during the hydraulic braking assist routine.

A method for controlling a brake pressure booster with hydraulic brake boosting wherein the activation of an additional pressure source takes place upon exceeding a specified brake cylinder pressure threshold value. The threshold value lying between 50% and 100%, preferably between 70% and 80%, of a pressure limit value, from which the operating travel/brake pressure curve without additional brake pressure assistance has a knee point. Further upon exceeding a specified piston rod activation travel limit value, which lies at 20% to 100% of the available travel, preferably at 40% to 60% of the available travel. Furthermore, the speed of the vehicle, its lateral deceleration and its longitudinal deceleration can be used as criteria. Deactivation takes place on falling below a specified piston rod deactivation travel limit value. Based on selection of activation/deactivation criteria additional brake pressure boosting can be operational during braking maneuvers.

A method of controlling an electric booster including a reaction disk, a boosting body and a pedal push rod connected to a pedal and configured to come into contact with the reaction disk, the electric booster being subjected to braking control according to a braking map, includes: a first braking control step of controlling and generating a reaction force at normal times in accordance with a pedal effort by compressing and expanding a fluid while moving the pedal push rod; and a second braking control step of controlling and generating the reaction force in accordance with the pedal effort only in a condition in which the reaction disk and the pedal push rod are in contact with each other by detecting a size of an air gap between the reaction disk and the pedal push rod.

In a method for operating a braking system of a vehicle by limiting brake pressure buildup during an activation of a brake actuating element, the rear wheel outlet valves of the rear wheel brake cylinders, which are respectively associated with a rear wheel of the vehicle, are controlled, at least temporarily, into an open state during the activation of the brake actuating element, and the front wheel inlet valves of the front wheel brake cylinders, which are respectively associated with a front wheel of the vehicle, are controlled, at least temporarily, into a closed state during the control of the rear wheel outlet valves into the open state.

An electronic brake system may be capable of providing a required hydraulic pressure continuously and constantly as well as a precise pressure control through a gear pump provided in a hydraulic pressure supply device. Also, the electronic brake system may be capable of minimizing a number of valves controlling hydraulic pressure flows to implement a simplified configuration and providing the braking by a pedal effort of a driver even when the brake system is abnormally operated.

A method for operating a braking system includes: limiting a brake pressure buildup in a brake circuit of the braking system to a response pressure of a storage volume of the brake circuit by controlling a first wheel outlet valve of a first wheel brake cylinder of the brake circuit into an opened state at least temporarily during an increasing activation intensity of an activation of a brake actuating element connected to a master break cylinder; providing an additional reduction of a brake pressure in the brake circuit to below the response pressure during a constant activation intensity by controlling the first wheel outlet valve into a closed state; and activating a brake booster in such a way that an internal pressure present in the master brake cylinder is reduced with the aid of the activated brake booster.