Brake control device, brake system and operation method thereof

Abstract

The invention relates to a hydraulic electronic brake control device (100, 100 ') for hydraulically actuatable wheel brakes (8a, 8b), having an electrically actuatable hydraulic pressure source (5), having an inlet valve (6a, 6b) for each hydraulically actuatable wheel brake (8a, 8b), and having an outlet valve (7a, 7b) for each hydraulically actuatable wheel brake (8a, 8b), the invention relates to a brake control device (100, 100 ') for a motor vehicle, comprising at least two hydraulically actuatable wheel brakes (8a, 8b), and comprising a pressure medium reservoir (4), the brake control device (100, 100') comprising a pressure buildup wheel connection (61a, 61b) and a pressure relief wheel connection (62a, 62b) for at least one of the hydraulically actuatable wheel brakes (8a, 8b), and a brake system for a motor vehicle, comprising at least two hydraulically actuatable wheel brakes (8a, 8b), the invention relates to a hydraulic brake system (1) comprising hydraulically actuatable wheel brakes (8a, 8b) and a hydraulic electronic brake control device (100, 100 '), which comprises an electrically controllable hydraulic pressure source (5), an inlet valve (6a, 6b) for each hydraulically actuatable wheel brake (8a, 8b), an outlet valve (7a, 7b) for each hydraulically actuatable wheel brake (8a, 8b), and a pressure medium reservoir, for each hydraulically actuatable wheel brake (8a, 8b), the brake control device (100, 100 ') is connected to the hydraulically actuatable wheel brake (8a, 8b) via a first hydraulic connection element (81a, 81b) and a second hydraulic connection element (82a, 82b). The invention further relates to a method for operating such a brake system.

Description

[0001] The invention relates to a brake control device according to the preamble of claim 1 , a brake system for a motor vehicle according to the preamble of claim 8 , and a method for operating a brake system.

[0002] DE 10 2015 001 541 A1 discloses a hydraulically operated wheel brake having a brake disc, a brake caliper and a brake pad, wherein the brake pad has a chamber which can be loaded with a brake fluid and expands during a braking phase, in which process the brake pad is pressed against the brake disc, the wheel brake having an inlet formed on the brake pad for introducing the brake fluid into the chamber, the brake pad having a return section separated from the inlet section for the brake fluid to flow out of the chamber. In order to cool the brake pad, the brake system is designed such that the brake fluid can circulate through the chamber via the inlet and the return section by means of a delivery unit.

[0003] A brake-by-wire system with a hydraulic electronic brake control and four hydraulically actuatable wheel brakes is known from WO 2018 / 130393 A1. The brake control comprises a master brake cylinder, an electrically controllable pressure source and exactly four hydraulic wheel connections for each of the four hydraulically actuatable wheel brakes. Each of the four hydraulically actuatable wheel brakes has a single connection piece which is connected to exactly one of the four hydraulic wheel connections of the hydraulic electronic brake control.

[0004] DE 10 2012 217 825 A1 discloses a so-called combined brake-by-wire system having a hydraulic-electronic brake control device with a master brake cylinder and an electrically controllable pressure source, two hydraulically actuable wheel brakes, and two wheel brakes each actuable by an electromechanical actuator. Each of the two hydraulically actuable wheel brakes has a single connection element which is connected to exactly one of the two hydraulic wheel connections of the hydraulic-electronic brake control device.

[0005] Such brake-by-wire systems must be filled with brake fluid (pressure medium) at the manufacturer's plant of the motor vehicle manufacturer by means of a filling device and, if necessary, suitably evacuated.

[0006] The object of the present invention is to provide a hydraulic-electronic brake control device for a brake-by-wire system and a brake-by-wire system which enable self-filling, i.e. filling with pressure medium without additional filling devices, so that a time-consuming and error-prone process in the manufacturer's plant of a motor vehicle manufacturer is avoided.

[0007] This object is achieved by a hydraulic-electronic brake control device as claimed in claim 1 and a brake system as claimed in claim 8 .

[0008] A further object of the present invention is to provide methods for operating a brake system which generate, restore or improve the functionality of the brake system.

[0009] This object is achieved by a method according to claim 14 .

[0010] The concept of the invention with respect to a hydraulic-electronic brake control is based on the fact that the hydraulic-electronic brake control for hydraulically actuatable wheel brakes comprises an electrically controllable hydraulic pressure source, an inlet valve for each hydraulically actuatable wheel brake, an outlet valve for each hydraulically actuatable wheel brake, and a pressure medium reservoir. For at least one of the hydraulically actuatable wheel brakes, the brake control has a pressure-building wheel connection and a pressure-relief wheel connection. This means that for at least one hydraulically actuatable wheel brake, the brake control has two separate wheel connections, namely a pressure-building wheel connection and a pressure-relief wheel connection.

[0011] The brake control device offers the advantage that the brake control device can convey pressure medium from the electrically controllable pressure source via the inlet valve, the pressure-building wheel connection, the wheel brake and the pressure-relief wheel connection of the wheel brake to the pressure medium reservoir in an automatically and electrically controlled manner for at least one of the hydraulically actuable wheel brakes by suitable actuation of the electrically controllable pressure source and the inlet valve and the outlet valve. This enables self-filling or wheel brake flushing by the brake system itself when the brake system is already installed in the vehicle.

[0012] Preferably, for at least one of the hydraulically actuable wheel brakes, the pressure-building wheel connection is connected to an electrically controllable hydraulic pressure source via an inlet valve assigned to the hydraulically actuable wheel brake, and the pressure-relieving wheel connection is connected to a pressure medium reservoir via an outlet valve assigned to the hydraulically actuable wheel brake.

[0013] The brake control device is designed for hydraulically actuable wheel brakes, ie, for at least two hydraulically actuable wheel brakes. Accordingly, the brake control device comprises at least two inlet valves and at least two outlet valves.

[0014] Preferably, the brake control device is designed for exactly two hydraulically actuatable wheel brakes. The brake control device then comprises two inlet valves and two outlet valves, respectively, for the two hydraulically actuatable wheel brakes. Particularly preferably, the brake control device comprises (exactly) two pressure-building wheel connections and two pressure-relief wheel connections, wherein the first pressure-building wheel connection is connected to an electrically controllable hydraulic pressure source via a first inlet valve, the first pressure-relief wheel connection is connected to a pressure medium reservoir via a first outlet valve, the second pressure-building wheel connection is connected to an electrically controllable hydraulic pressure source via a second inlet valve, and the second pressure-relief wheel connection is connected to a pressure medium reservoir via a second outlet valve. Particularly preferably, the first inlet valve is connected to the pressure connection of the hydraulically actuatable first wheel brake via the first pressure-building wheel connection and the first hydraulic connection element, the first outlet valve is connected to the discharge connection of the hydraulically actuatable first wheel brake via the first pressure-relieving wheel connection and the second hydraulic connection element, the second inlet valve is connected to the pressure connection of the hydraulically actuatable second wheel brake via the second pressure-building wheel connection and the further first hydraulic connection element, and the second outlet valve is connected to the discharge connection of the hydraulically actuatable second wheel brake via the second pressure-relieving wheel connection and the further second hydraulic connection element.

[0015] The pressure medium reservoir is preferably a pressure medium reservoir at atmospheric pressure.

[0016] According to a preferred embodiment, the brake control device has a pressure-building wheel connection and a pressure-relief wheel connection for each hydraulically actuatable wheel brake, wherein for each of the hydraulically actuatable wheel brakes, the pressure-building wheel connection is (in each case) connected to an electrically controllable hydraulic pressure source via an inlet valve assigned to the (corresponding) hydraulically actuatable wheel brake, and the pressure-relief wheel connection is connected to a pressure medium reservoir via an outlet valve assigned to the (corresponding) hydraulically actuatable wheel brake. This means that for each of the hydraulically actuatable wheel brakes, the hydraulic-electronic brake control device has two (separate) wheel connections. For each hydraulically actuatable wheel brake, the two (separate) wheel connections are a pressure-building wheel connection for supplying pressure medium from an electrically controllable pressure source via a brake control device inlet valve assigned to the corresponding wheel brake into the corresponding wheel brake, and a pressure-relief wheel connection for discharging pressure medium from the corresponding wheel brake via a brake control device outlet valve assigned to the corresponding wheel brake into the pressure medium reservoir. The brake control device offers the advantage that it can convey pressure medium from the electrically controllable pressure source via the inlet valve of the respective wheel brake, the associated pressure-building wheel connection, the respective wheel brake and the associated pressure-relief wheel connection to the pressure medium reservoir in an automatically and electrically controlled manner for each of the hydraulically actuable wheel brakes by suitable actuation of the electrically controllable pressure source and the inlet valve and the outlet valve. This enables self-filling or flushing of the wheel brakes or the entire brake system by the brake system itself when the brake system is already installed in the vehicle.

[0017] In the case of a hydraulic electronic brake control device designed for two hydraulically actuatable wheel brakes, the brake control device therefore preferably has two pressure-building wheel connections and two pressure-relief wheel connections, thus a total of four separate wheel connections for connecting the two hydraulically actuatable wheel brakes. The two pressure-building wheel connections are provided for building up pressure in the respective wheel brakes, in particular by means of an electrically controllable pressure source via an inlet valve assigned to the respective wheel brake, and the two pressure-relief wheel connections are provided for releasing the pressure in the respective wheel brakes, in particular via an outlet valve assigned to the respective wheel brake to release the pressure in the respective wheel brake into a pressure medium reservoir.

[0018] If the hydroelectronic brake control device is designed for four hydraulically actuatable wheel brakes, the brake control device preferably has four pressure-building wheel connections and four pressure-relieving wheel connections, ie a total of eight individual wheel connections.

[0019] Preferably, for at least one of the hydraulically actuable wheel brakes, particularly preferably for each of the hydraulically actuable wheel brakes, no hydraulic connecting line is arranged in the brake control device between the wheel brake-side connection of the corresponding inlet valve of the hydraulically actuable wheel brake and the wheel brake-side connection of the corresponding outlet valve of the hydraulically actuable wheel brake.

[0020] Preferably, the hydraulic electronic brake control device does not include any other hydraulic pressure source besides the electrically controllable hydraulic pressure source. The brake control device particularly preferably does not include a master brake cylinder that can be actuated by a brake pedal and actuates the wheel brakes in a hydraulic fallback stage. The brake control device also particularly preferably does not include a second electrically controllable hydraulic pressure source.

[0021] Preferably, the electrically controllable hydraulic pressure source is formed by a cylinder-piston arrangement with a pressure chamber and a piston, wherein the piston can be moved back and forth by an electromechanical actuator. This means that pressure medium can be pushed into the wheel brakes and sucked out of them. To build up brake pressure, the piston is moved forward (in the brake actuation direction), and to relieve brake pressure, the piston is moved backward (i.e., opposite to the brake actuation direction). To replenish pressure medium from a pressure medium reservoir into the pressure source, the piston is also moved backward (i.e., opposite to the brake actuation direction).

[0022] Preferably, the electrically controllable hydraulic pressure source, in particular its pressure chamber, is connected via an electrically actuable sequence valve / switch-on valve to a brake line section to which the inlet valve of the brake control device is connected. Particularly preferably, the sequence valve is configured to be normally closed. By means of the sequence valve, the pressure source for replenishing the pressure medium from the pressure medium reservoir can be hydraulically separated from the inlet valve.

[0023] Preferably, the brake line section can be connected to the pressure medium reservoir via an electrically actuatable disconnect valve. This allows the inlet valve to be hydraulically connected to the pressure medium reservoir and thus to decompress the wheel brakes. Particularly preferably, the disconnect valve is configured to be normally open and thus, in a non-actuated, powered-down state of the brake control device or the brake system, the wheel brakes are hydraulically connected to the pressure medium reservoir.

[0024] According to a preferred embodiment, the brake line section is hydraulically connected directly to the pressure medium reservoir via a separating valve and a compensating line section.

[0025] According to another preferred embodiment, the brake line section is connected to the pressure chamber of the master brake cylinder via a separating valve and a line section. Particularly preferably, when the master brake cylinder piston is not actuated, the pressure chamber of the master brake cylinder is connected to the pressure medium reservoir via one or more compensation holes. When the master brake cylinder piston is (fully) actuated in the actuating direction, the hydraulic connection between the pressure chamber and the pressure medium reservoir is disconnected.

[0026] The pressure source is preferably formed by a cylinder-piston arrangement with a hydraulic pressure chamber, a suction connection and a pressure connection, the piston of which can be moved back and forth or pushed back and forth by the electromechanical actuator. The suction connection is particularly preferably connected to the pressure medium reservoir via a replenishment line with a non-return valve that opens in the flow direction toward the pressure chamber. The pressure connection is preferably connected to the brake line section via a sequence valve.

[0027] Preferably, the pressure medium reservoir has two reservoir chambers separated by a partition, wherein the outlet valve and thus one or more pressure-relief wheel connections are connected to one reservoir chamber, and the replenishment line of the electrically controllable hydraulic pressure source is connected to the other reservoir chamber. This allows the brake control device to be self-ventilated (or flushed), in particular when the pressure medium is changed in a workshop (brake fluid change), or particularly preferably when the vehicle is running. If steam bubbles appear in the brake system, for example due to reheating when the vehicle is stationary, this can be recognized by the increased volume registration in the test routine of the brake system after the vehicle has been parked. Therefore, a self-ventilation cycle is then started, in which the pressure medium reservoir acts as a bubble separator and the separation into two reservoir chambers prevents the foamed pressure medium (brake fluid) from being sucked in again.

[0028] The concept of the invention with respect to a brake system is based on the fact that the brake system comprises at least two hydraulically actuatable wheel brakes and a hydraulic-electronic brake control device, wherein the hydraulic-electronic brake control device comprises an electrically controllable hydraulic pressure source, an inlet valve for each hydraulically actuatable wheel brake, an outlet valve for each hydraulically actuatable wheel brake, and a pressure medium reservoir. For each of the hydraulically actuatable wheel brakes, the brake control device is connected to the hydraulically actuatable wheel brake via a first hydraulic connection element and a second (i.e., separate) hydraulic connection element. This means that, for each hydraulically actuatable wheel brake, the brake system has two separate hydraulic connection elements, i.e., a first hydraulic connection element and a second hydraulic connection element, via which the brake control device is connected to the corresponding / respective hydraulically actuatable wheel brake.

[0029] The brake system offers the advantage that, for each wheel brake, pressure medium from the brake control can be conducted via a first hydraulic connection element to the hydraulically actuatable wheel brake, and pressure medium can be transferred individually from the wheel brake to the brake control via a second hydraulic connection element. Thus, by suitable control, advantageously automatic control, of the electrically actuatable pressure source, self-filling or flushing of the wheel brakes can be achieved by the brake system.

[0030] Preferably, the brake control device has a pressure-building wheel connection and a pressure-relief wheel connection for each of the hydraulically actuable wheel brakes. Particularly preferably, for each of the hydraulically actuable wheel brakes, the pressure-building wheel connection is connected to an electrically controllable hydraulic pressure source via an inlet valve assigned to the respective hydraulically actuable wheel brake, and the pressure-relief wheel connection is connected to a pressure medium reservoir via an outlet valve assigned to the respective hydraulically actuable wheel brake. Thus, for each hydraulically actuable wheel brake, pressure medium can be conducted from the brake control device via the pressure-building wheel connection and the first hydraulic connection element into the hydraulically actuable wheel brake, flow through the wheel brake, and be discharged into the brake control device via the second hydraulic connection element and the pressure-relief wheel connection.

[0031] Preferably, for each hydraulically actuatable wheel brake, a first hydraulic connection element connects an inlet valve assigned to the hydraulically actuatable wheel brake, particularly preferably via a pressure-building wheel connection of a brake control device assigned to the inlet valve, to a pressure connection of the hydraulically actuatable wheel brake. This connection is particularly suitable for building up pressure in the hydraulically actuatable wheel brake by means of a hydraulic pressure source.

[0032] Preferably, for each hydraulically actuatable wheel brake, a second hydraulic connection element connects an outlet valve assigned to the hydraulically actuatable wheel brake, particularly preferably via a pressure relief wheel connection of the brake control device assigned to the outlet valve, to a discharge connection of the hydraulically actuatable wheel brake. This connection is particularly suitable for discharging pressure from the hydraulically actuatable wheel brake into a pressure medium reservoir of the brake control device.

[0033] Preferably, the brake control device is designed as a hydraulic electronic brake control device according to the invention.

[0034] The pressure medium reservoir is preferably a pressure medium reservoir at atmospheric pressure.

[0035] According to a preferred embodiment of the brake system, the brake system comprises at least one wheel brake that can be actuated by an electromechanical actuator. Particularly preferably, the brake system comprises two wheel brakes that can each be actuated by an electromechanical actuator. The two electromechanically actuable wheel brakes are very particularly preferably assigned to a second vehicle axle of the motor vehicle. Advantageously, the second vehicle axle is the rear axle of the motor vehicle. Particularly preferably, the brake system comprises exactly two wheel brakes that can each be actuated by an electromechanical actuator (i.e., two electromechanically actuable wheel brakes).

[0036] The brake system preferably comprises exactly two hydraulically actuatable wheel brakes. Particularly preferably, these wheel brakes are assigned to a first vehicle axle of the motor vehicle. Very particularly preferably, the two hydraulically actuatable wheel brakes are assigned to the front axle of the motor vehicle.

[0037] According to a preferred embodiment of the brake system, the brake system comprises two hydraulically actuatable wheel brakes, a hydraulic-electronic brake control, and two electromechanically actuatable wheel brakes. The brake system particularly preferably comprises exactly two hydraulically actuatable wheel brakes.

[0038] Preferably, the brake system comprises two hydraulically actuatable wheel brakes, a hydraulic-electronic brake control device according to the invention, and two electromechanically actuatable wheel brakes. The brake system particularly preferably comprises exactly two hydraulically actuatable wheel brakes.

[0039] Preferably, the brake system comprises an actuating device which is designed to determine an actuating signal which quantifies a braking desire caused by an actuation by the vehicle driver, the actuating device being connected to the hydraulic-electronic brake control device via a signal connection or a data connection for transmitting the actuating signal. Particularly preferably, the actuating device is in the form of an electronic brake pedal (ePedal). Particularly preferably, there is no mechanical-hydraulic connection from the actuating device to the brake control device or the hydraulically actuatable wheel brakes.

[0040] Preferably, the hydraulic electronic brake control device comprises a first electronic control and adjustment unit and a second electronic control and adjustment unit, wherein the electrically controllable hydraulic pressure source is controlled by the second electronic control and adjustment unit, and the inlet valve and the outlet valve are controlled by the first electronic control and adjustment unit.

[0041] Preferably, the electrically controllable hydraulic pressure source is detachably hydraulically connected to the inlet valve via an electrically actuable sequence valve, wherein the sequence valve is actuated by the second electronic control and regulating unit.

[0042] The isolating valve between the brake line section and the pressure medium reservoir is preferably actuated by a second electronic open-loop control unit.

[0043] Preferably, the brake system comprises a first electrical zone and a second electrical zone, wherein the second electrical zone is independent of the first electrical zone.

[0044] Preferably, the first electronic control and regulation unit of the hydraulic electronic brake control device and / or the first electrical partition of the brake system is powered by a first power supply, and the second electronic control and regulation unit of the hydraulic electronic brake control device and / or the second electrical partition of the brake system is powered by a second power supply independent of the first power supply. Therefore, the first energy source is part of the first electrical partition, and the second energy source is part of the second electrical partition.

[0045] Preferably, the braking system comprises two wheel brakes which can each be actuated by an electromechanical actuator, wherein one of the wheel brakes actuable by the electromechanical actuator belongs to a first electrical partition of the braking system and the other of the wheel brakes actuable by the electromechanical actuator belongs to a second electrical partition of the braking system.

[0046] Preferably, the brake system comprises two wheel brakes each actuatable by an electromechanical actuator (i.e., two electromechanically actuatable wheel brakes), wherein one of the wheel brakes actuatable by the electromechanical actuator is supplied with electrical energy by a first power source, and the other wheel brake actuatable by the electromechanical actuator is supplied with electrical energy by a second power source independent of the first power source. The brake control device is particularly preferably supplied by the first power source and the second power source. Very particularly preferably, the second electronically controlled regulating unit and the electrically controllable hydraulic pressure source of the brake control device are supplied with electrical energy by the first power source, and the first electronically controlled regulating unit and the inlet valve and the outlet valve are supplied with electrical energy by the second power source.

[0047] Preferably, the brake system comprises two electromechanically actuatable wheel brakes, wherein each of the electromechanically actuatable wheel brakes comprises a dedicated electronic open-loop control unit for controlling an electromechanical actuator of the electromechanically actuatable wheel brake.

[0048] Preferably, the brake system has a first data bus, in particular a first CAN bus, and a second data bus, in particular a second CAN bus, or is connected to the first data bus and the second data bus.

[0049] Preferably, the first data bus connects a first electronic control and regulation unit of the hydraulic electronic brake control device and two electronic control and regulation units of the electromechanically actuatable wheel brakes.

[0050] Preferably, the second data bus connects the first electronic open-loop control unit of the hydraulic-electronic brake control device and the two electronic open-loop control units of the electromechanically actuatable wheel brakes.

[0051] Preferably, the first data bus and the second data bus are connected to a further electronic control and regulation unit, in particular a central vehicle control / regulation unit. Particularly preferably, the operating device is simply electrically connected to the further electronic control and regulation unit.

[0052] Preferably, each of the two electronic control and regulation units for controlling one of the electromechanical actuators of the electromechanically actuable wheel brakes is connected to both the first data bus and the second data bus. This provides the advantage that the driver's braking request is redundantly supplied to the two electromechanically actuable wheel brakes.

[0053] Preferably, the first data bus connects the second electronic control and regulation unit of the hydraulic electronic brake control device and the two electronic control and regulation units of the electromechanically actuatable wheel brakes.

[0054] Preferably, the hydraulically actuatable wheel brakes of the brake system each comprise a pressure medium chamber for actuating a brake element, wherein the pressure medium chamber is connected to a pressure connection of the wheel brake for supplying pressure medium from a brake control device or for connection to one of the inlet valves of the brake control device. In each case, the pressure medium chamber of the wheel brake is additionally connected to a discharge connection of the wheel brake for discharging pressure medium into a pressure medium reservoir of the brake control device or for connection to one of the outlet valves of the brake control device.

[0055] Preferably, the hydraulically actuatable wheel brakes do not have any other ventilation connections equipped with a bleed screw or a bleed valve.

[0056] Preferably, the drain connection is arranged above the pressure connection when one of the hydraulically actuable wheel brakes is installed in the vehicle. Preferably, the drain connection is arranged above the pressure connection for each wheel brake when the hydraulically actuable wheel brakes of the brake system are installed.

[0057] The idea of ​​the invention with regard to the method for operating a brake system according to the invention is based on the fact that the brake control device is used to carry out a flushing cycle in which

[0058] a) by actuating an electrically controllable hydraulic pressure source, in particular in the brake actuation direction, pressure medium is moved via a first inlet valve of the inlet valves, via a first hydraulically actuable wheel brake assigned to the first inlet valve, via an outlet valve assigned to the first hydraulically actuable wheel brake into or in the direction of the pressure medium reservoir, in particular subsequently,

[0059] b) by actuating the electrically controllable hydraulic pressure source, in particular actuating the electrically controllable hydraulic pressure source in a direction opposite to the brake actuation direction, pressure medium is sucked from the pressure medium reservoir into the electrically controllable hydraulic pressure source,

[0060] In particular, steps a) and b) are repeated cyclically.

[0061] Preferably, the pressure medium reservoir of the brake system has a first reservoir chamber and a second reservoir chamber, wherein the reservoir chambers are separated from each other by a partition, an outlet valve is connected to the second reservoir chamber, and a replenishment line of an electrically controllable hydraulic pressure source is connected to the first reservoir chamber. In step a), the pressure medium is delivered to the second reservoir chamber, and in step b), the pressure medium is sucked out of the first reservoir chamber into the pressure source. For example, a brake fluid replacement (pressure medium replacement) can be easily carried out in a workshop by removing old pressure medium from the second reservoir chamber of the pressure medium reservoir and filling new pressure medium into the first reservoir chamber of the pressure medium reservoir.

[0062] Preferably, the method is first carried out for one of the hydraulically actuatable wheel brakes and then for the other of the hydraulically actuatable wheel brakes. Particularly preferably, a leak test is then carried out on the brake system by means of the brake control device, in which a test pressure is built up and maintained by means of an electrically controllable hydraulic pressure source.

[0063] Preferably, in step a), before operating the electrically controllable hydraulic pressure source, in particular in the brake actuation direction, the sequence valve of the hydraulic electronic brake control device is opened, the separation valve of the hydraulic electronic brake control device is closed, and the outlet valve assigned to the first hydraulically actuable wheel brake is opened.

[0064] Preferably, step a) is ended when the piston of the electrically controllable hydraulic pressure source reaches a predetermined end point in the brake actuation direction, and the sequence valve of the hydraulic electronic brake control device is closed before step b) is started.

[0065] The method according to the invention is preferably carried out after the brake system has been installed. Particularly preferably, the method is carried out after the brake system has been installed for filling hydraulically actuatable wheel brakes with pressure medium. Particularly preferably, the method is carried out at the manufacturer of the motor vehicle.

[0066] Preferably, the method according to the invention is carried out for cooling the pressure medium. Preferably, the method according to the invention is carried out if it is determined according to a monitoring method that the brake system is under thermal load or one of the wheel brakes is under thermal load. Particularly preferably, the monitoring method is carried out according to a brake temperature model and / or according to sensor data, in particular according to data of a force sensor with a temperature output.

[0067] Preferably, the method according to the invention is performed to ventilate a brake control device. Preferably, the method according to the invention is repeated and / or performed when predetermined conditions exist. Particularly preferably, the method is performed repeatedly according to a predetermined time schedule.

[0068] Further preferred embodiments of the invention will emerge from the dependent claims and from the following description with reference to the accompanying drawings,

[0069] In the attached picture:

[0070] Figure 1 A first exemplary embodiment of a brake control device according to the present invention is shown.

[0071] Figure 2 It shows that according to the present invention Figure 1 An exemplary embodiment of a brake control device for a brake system,

[0072] Figure 3 A second exemplary embodiment of a brake control device according to the present invention is shown.

[0073] Figure 4 It shows that according to the present invention Figure 3 An exemplary embodiment of a brake control device for a brake system.

[0074] Figure 1 A first exemplary embodiment of a brake control device 100 according to the invention is schematically illustrated. The exemplary hydraulic-electronic brake control device 100 is designed for actuating two hydraulically actuable wheel brakes 8a, 8b. The brake control device 100 comprises an electrically actuable hydraulic pressure source 5, comprising a pressure medium reservoir 4 at atmospheric pressure, and for each wheel brake 8a, 8b, comprising an electrically actuable inlet valve 6a, 6b and an electrically actuable outlet valve 7a, 7b.

[0075] Advantageously, the inlet valves 6a, 6b are normally open, whereas the outlet valves 7a, 7b are normally closed.

[0076] As an example, the brake control device 100 includes a first electronic control and regulation unit 11 (ECU1) and a second electronic control and regulation unit 12 (ECU2). Alternatively, the brake control device 100 may also include an electronic control and regulation unit ECU that includes two separate areas in the form of, for example, a first circuit board (corresponding to 11) and a second circuit board (corresponding to 12). The following content is then correspondingly applicable to the first area and the second area (first printed circuit board and second printed circuit board) that are replacements for the first electronic control and regulation unit 11 and the second electronic control and regulation unit 12.

[0077] The brake control device 100 is designed, for example, as a hydraulic electronic unit (HECU) having a hydraulic control and regulation unit 60 (HCU, also referred to as a valve block) and two electronic control and regulation units 11 , 12 (ECU1 , ECU2 ).

[0078] The electrically controllable hydraulic pressure source 5 is designed as a hydraulic cylinder piston device (i.e., as a single-circuit hydraulic electronic actuator (linear actuator)) having a pressure chamber 37 and a piston 36, whose piston 36 can be moved back and forth by a schematically indicated motor 35 with a likewise schematically shown rotation-translation mechanism 39 connected in between. A rotor position sensor, which is only schematically indicated, for detecting the rotor position of the motor 35 is denoted by reference numeral 44.

[0079] The pressure chamber 37 of the pressure source 5 is connected to the brake line section 13, to which the inlet valves 6a, 6b are connected, via an electrically actuatable sequence valve 26. The sequence valve 26 is advantageously normally closed. For this purpose, the pressure chamber 37 is connected to the sequence valve 26 via a system pressure line 38, which is connected to the brake line section 13 on the output side.

[0080] A pressure sensor 19 which determines the system pressure generated by pressure source 5 is arranged in brake line section 13 .

[0081] In order to replenish the pressure medium into the pressure source 5, the pressure chamber 37 is connected to the pressure medium reservoir 4, preferably to the first chamber / LAC chamber 4a of the pressure medium reservoir, via a replenishing line 42, which has a non-return valve (replenishing valve) 53 that opens in the flow direction toward the pressure chamber 37. Therefore, by moving the piston 36 backward with the sequence valve 26 closed, the pressure medium can flow out of the pressure medium reservoir 4 or preferably from the first chamber 4a of the pressure medium reservoir, and flow into the pressure chamber 37 via the replenishing line 42.

[0082] Apart from pressure source 5 , exemplary brake control device 100 comprises no further pressure sources, ie neither further electrically actuatable pressure sources nor a master brake cylinder actuatable by a brake pedal are provided.

[0083] For each of the hydraulically actuatable wheel brakes 8a, 8b, the brake control device comprises a pressure-building wheel connection 61a, 61b and a (separate) pressure-relief wheel connection 62a, 62b. This means that two separate wheel connections (61 and 62) are provided for each hydraulically actuatable wheel brake 8a, 8b, namely a pressure-building wheel connection 61a, 61b and a pressure-relief wheel connection 62a, 62b, which are not directly connected to one another in the brake control device 100. In particular, the wheel brake-side connection of the respective inlet valve 6a, 6b is not connected to the wheel brake-side connection of the corresponding outlet valve 7a, 7b via a hydraulic connection (connecting line).

[0084] For each hydraulically actuatable wheel brake 8a, 8b, an electrically controllable hydraulic pressure source 5 is connected to a pressure-building wheel connection 61a, 61b via a corresponding inlet valve 6a, 6b assigned to the hydraulically actuatable wheel brake 8a, 8b. For each hydraulically actuatable wheel brake 8a, 8b, a pressure-relief wheel connection 62a, 62b is connected to the pressure medium reservoir 4 via a corresponding outlet valve 7a, 7b assigned to the hydraulically actuatable wheel brake 8a, 8b. As an example, the outlet valves 7a, 7b are connected to the pressure medium reservoir 4, preferably to the second chamber / return chamber 4b of the pressure medium reservoir, via a return line 14 (common in terms of sections). For pressure relief by means of the outlet valves 7a, 7b, the pressure medium portion discharged via the outlet valves 7a, 7b flows via the return line 14 into the pressure medium reservoir 4 or preferably into the second chamber of the pressure medium reservoir.

[0085] Correspondingly, for each of the hydraulically actuatable wheel brakes 8a, 8b, the brake control device 100 is connected to the hydraulically actuatable wheel brakes 8a, 8b via a first hydraulic connecting element (first wheel line) 81a, 81b and via a second hydraulic connecting element (second wheel line) 82a, 82b.

[0086] The first hydraulic connection element (first wheel line) 81a or 81b is connected on the one hand to the pressure-building wheel connection 61a or 61b of the brake control device assigned to the wheel brake 8a or 8b (and therefore to the corresponding inlet valve 6a or 6b), and on the other hand to the pressure connection 801a or 801b of the wheel brake 8a or 8b. The first wheel line 81a or 81b serves to build up pressure in the wheel brake (for building up wheel brake pressure) by means of the hydraulic pressure source 5.

[0087] The second hydraulic connection element (second wheel line) 82a, 82b is connected on the one hand to the pressure relief wheel connection 62a or 62b of the brake control device 100 and on the other hand to the discharge connection (802a or 802b) of the wheel brake 8a or 8b, which is assigned to the wheel brake 8a or 8b (and is therefore connected to the corresponding outlet valve 7a or 7b). Via the second wheel line 82a or 82b, the pressure medium is discharged from the wheel brake 8a or 8b via the outlet valve 7a or 7b into the pressure medium reservoir 4 of the brake control device 100 (in order to relieve the wheel brake pressure).

[0088] Connected in parallel to inlet valves 6 a , 6 b are each nonreturn valves 16 a , 16 b which open in the direction of brake circuit supply line 13 .

[0089] In order to be able to decompress the wheel brakes 8a, 8b as required, i.e., to be able to balance the pressure of the wheel brakes 8a, 8b with the atmosphere, the brake line section 13 is connected to the pressure medium reservoir 4 via an electrically actuatable isolating valve 23, and the equalizing line section 41 is preferably connected to the second chamber / return chamber 4b of the pressure medium reservoir. The isolating valve 23 is advantageously normally open, in order to ensure pressure balance of the wheel brakes with the atmosphere, for example in the switched-off, de-energized state of the brake system.

[0090] Advantageously, the level measuring device 50 is arranged for determining the pressure medium level / state in the pressure medium reservoir 4. Preferably, the level measuring device 50 is arranged in the first chamber / LAC chamber 4a of the pressure medium reservoir.

[0091] For individual electrical components or electrically controllable components of the brake control device 100 or the brake system that can be controlled, evaluated, etc. (see Figure 2 )’s electrical attachment, connection and power supply, setting up a first electrical partition A and a second electrical partition B that are electrically independent of each other.

[0092] In the figure, those electrical components that are assigned to or belong to the first electrical partition A are indicated by arrows with an A. Those electrical components that are assigned to or belong to the second electrical partition B are indicated by arrows with a B.

[0093] The first electronic control and regulation unit 11 is assigned to or belongs to the first electrical partition A, while the second electronic control and regulation unit 12 is assigned to or belongs to the second electrical partition B. Accordingly, the electronic control and regulation unit 11 and the second control and regulation unit 12 are electrically independent.

[0094] In order to supply electric energy to the brake control device 100 or the brake system, a first power source PWR2 (e.g., a vehicle electrical system) and a second power source PWR1 (e.g., a second vehicle electrical system) independent of the first energy source are provided. The first power source PWR2 supplies energy to the first electrical partition A, while the second power source PWR1 supplies energy to the second electrical partition B.

[0095] The second electronic control and regulation unit 12 controls the pressure source 5. Accordingly, the first pressure source 5 is assigned to the second electrical partition B or is associated with the second electrical partition. According to the example, the first pressure source 5 is supplied with energy (energy from the second power supply PWR1) via the second electronic control and regulation unit 12. According to the example, the first pressure source 5 can be controlled by the second electronic control and regulation unit 12 or exclusively by the second electronic control and regulation unit.

[0096] In order to achieve redundancy in the control of the pressure source 5, it is provided according to a preferred embodiment that both the two partitions A and B (or the two control and adjustment units 11, 12 and the two circuit boards) of the brake control device 100 are designed to control the motor-driven pressure source 5 based on the control information. For this purpose, for example, both the partitions A, B (or the two control and adjustment units 11, 12 or the two circuit boards) are connected to the controller of the power electronics of the motor 35. In this way, even if one of the partitions A, B fails, the target control of the hydraulic pressure in the brake control device 100 is still possible. The pressure source 5 can be controlled by / by the second electronic control and adjustment unit 12, and can be controlled by / by the first electronic control and adjustment unit 11.

[0097] The remaining components of the brake system are advantageously assigned to the first electronic control and regulation unit 11 (section A) or the second electronic control and regulation unit 12 (section B). That is, the components are controlled or manipulated and / or supplied with electrical energy by the control and regulation unit and / or are connected to the control and regulation unit on the signal side and / or are evaluated by the control and regulation unit. In order to avoid further redundancy, it is advantageous that the components can be controlled or manipulated, supplied with electrical energy, evaluated only or exclusively by one of the two electronic control and regulation units 11, 12 and not by the other electronic control unit, or can be connected to only or exclusively by one of the two electronic control and regulation units on the signal side and not by the other electronic control unit.

[0098] In order to be able to control the pressure source 5 , a rotor position sensor 44 is assigned to the second electrical section B. The signal from this sensor is supplied to the second electronic open-loop control and regulating unit 12 and is evaluated and processed by the latter.

[0099] The sequence valve 26 and the isolating valve 23 are also assigned to the second electrical section B and are actuated by the second electronic control and regulating unit 12 .

[0100] Furthermore, the signal from the fill level measuring device 50 is supplied to the second electronic control and regulating unit 12 and evaluated and processed by it.

[0101] Inlet valves 6 a - 6 d and outlet valves 7 a - 7 d are assigned to the first electrical section A and are controlled by a first electronic control and regulating unit 11 .

[0102] A pressure sensor 19 is also assigned to the first electrical zone A. The signal from said sensor is supplied to the first electronic control and regulation unit 11 and evaluated and processed by it.

[0103] Figure 2 A first exemplary embodiment of a brake system according to the invention is schematically illustrated. Figure 2 The exemplary braking system comprises two hydraulically actuable wheel brakes 8a, 8b and two wheel brakes 80a, 80b, each of which can be actuated by an electromechanical actuator (also referred to as electromechanically actuable wheel brakes 80a, 80b for short), and Figure 1 A hydraulic electronic brake control device 100 is provided.

[0104] The hydraulically actuable wheel brakes 8a, 8b are arranged on the front axle of the vehicle (FL: left front wheel, FR: right front wheel), and the electromechanically actuable wheel brakes 80a, 80b (RL: left rear wheel, RR: right rear wheel) are arranged on the rear axle of the vehicle. Both the hydraulically actuable wheel brakes 8a, 8b and the electromechanically actuable wheel brakes 80a, 80b are designed as service brakes of the vehicle.

[0105] The brake system is connected to a (brake) operating device 300, which is designed to determine an operating signal that quantifies the braking desire caused by the operation of the vehicle driver. The operating device 300 with the brake pedal 51 is in the form of an electronic brake pedal (ePedal). This means that there is no mechanical-hydraulic connection from the operating device 300 to the brake control device 100 or to the hydraulically operable wheel brakes 8a, 8b. Direct mechanical / hydraulic operation of the wheel brakes 8a, 8b by means of the operating device 300 is not possible. The operating device 300 is connected to the brake control device 100 only via a signal connection or data connection 150 for transmitting the operating signal.

[0106] The pressure-building wheel connection portion 61a of the brake control device 100 is hydraulically connected to the pressure connection portion 801a of the wheel brake 8a via the first wheel pipeline 81a, and the pressure-relieving wheel connection portion 62a of the brake control device 100 is hydraulically connected to the discharge connection portion 802a of the wheel brake 8a via the second wheel pipeline 82a. Correspondingly, the pressure-building wheel connection portion 61b of the brake control device 100 is hydraulically connected to the pressure connection portion 801b of the wheel brake 8b via the first wheel pipeline 81b, and the pressure-relieving wheel connection portion 62b of the brake control device 100 is hydraulically connected to the discharge connection portion 802b of the wheel brake 8b via the second wheel pipeline 82b.

[0107] Each electromechanically actuatable wheel brake 80a , 80b comprises its own electronic control and regulation unit WCUa, WCUb (WCU: wheel control unit), for example, for actuating a corresponding electromechanical actuator of wheel brake 80a , 80b .

[0108] The wheel brake 80a is supplied with electric energy from the second power source (PWR1) (section B), while the wheel brake 80b is supplied with electric energy from the first power source (PWR2) (section A).

[0109] Each wheel FL, FR, RL, RR is assigned a wheel speed sensor WSS1, WSS2, WSS3, WSS4 (WSS: wheel speed sensor). The signals from the wheel speed sensors WSS3, WSS4 of the wheels with electromechanically operable wheel brakes 80a, 80b are input to the corresponding electronic control and regulation unit WCU. The signals from the wheel speed sensors WSS1, WSS2 of the wheels with hydraulically operable wheel brakes 8a, 8b are input to the first electronic control and regulation unit 11.

[0110] In addition, the brake system has a first data bus 57 ("vehicle bus 1"), in particular a CAN bus, which connects the first electronic control and regulation unit 11 with the electronic control and regulation units WCUa, WCUb. The brake system further comprises a second data bus 58 ("brake bus 2"), in particular a CAN bus, which connects the first electronic control and regulation unit 11 with the electronic control and regulation units WCUa, WCUb.

[0111] Preferably, the electromechanically actuatable wheel brakes 80 a , 80 b are designed in such a way that they also comprise a parking brake.

[0112] Instead of two (e.g. spatially separated) electronic control and regulation units 11 and 12, a (single) control and regulation unit ECU can be provided which comprises two electrically independent areas (e.g. in the form of two circuit boards). One area (e.g. the first circuit board) is then assigned to partition A and the other area (e.g. the second circuit board) is assigned to partition B.

[0113] The hydraulic electronic front axle actuator (brake control device 100) is composed of a hydraulic control unit and an electronic control unit (HCU and ECU). The hydraulic front wheel brakes 8a, 8b are each connected to the HCU via a double line (composed of a first wheel line 81a, b and a second wheel line 82a, b). In each case, one line is used to build up pressure (first wheel line 81a, b) and one line is used to unload pressure (second wheel line 82a, b).

[0114] The ECU has two partitions, here referred to as partition A and partition B. These partitions A, B are independent areas and each have their own microcontroller, which executes an adapted software program. The partitions A, B are connected to each other via an internal ECU data bus. Both partitions A, B can preferably intervene or control the actuators required for regulating the pressure by means of the pressure source 5.

[0115] Partition A is simply electrically connected to a redundant actuating device 300 (ePedal) (connection 150) and converts the detected driver's braking desire into corresponding bus signals for actuating the electromechanical rear wheel brakes 80a, 80b. For redundancy, the actuating device 300 (ePedal) is also simply electrically connected to an electronic control and regulation unit (ECU) 400 (connection 160), which is external (outside the brake system) and likewise converts the driver's desire into corresponding bus signals. Thus, even if the brake control device 100 fails completely, for example due to a connector failure, the driver's desire can still be transmitted (via the first data bus 57 ("vehicle bus 1") or the second data bus 58 ("brake bus 2")) to the rear wheel brakes 80a, 80b.

[0116] Figure 3 A second exemplary embodiment of a brake control device 100 ′ according to the present invention is schematically illustrated. Unlike the first exemplary embodiment, Figure 3 The brake control device 100 ′ comprises a hydraulic fallback stage for driver intervention in the wheel brakes 8 a, 8 b. For this purpose, the brake control device 100 ′ comprises a master brake cylinder 2 actuatable by means of a brake pedal 51 and a simulation device 3 interacting with the master brake cylinder 2 .

[0117] The master brake cylinder 2 has a piston 15 in a housing (which is formed by a valve block) which delimits a pressure chamber 17. In the non-actuated state of the master brake cylinder 2 / piston 15, the pressure chamber 17 is connected to the pressure medium reservoir 4 via radial holes formed in the piston 15 and a balancing line section 41, wherein this connection can be cut off by a relative movement of the piston 17 in the housing (when actuated). A parallel arrangement of a throttle valve and a non-return valve 27 closed toward the pressure medium reservoir 4 is arranged in the balancing line section 41. This means that the pressure chamber 17 is connected to the pressure medium reservoir 4, preferably to the second chamber / return chamber 4b of the pressure medium reservoir, via one or more compensation holes in the non-actuated state of the piston 15. When the piston 15 is (fully) actuated in the actuating direction, this connection between the pressure chamber 17 and the pressure medium reservoir 4 is cut off.

[0118] The pressure chamber 17 accommodates a return spring 9 which positions the piston 15 in the starting position when the master brake cylinder 2 is not actuated. The piston rod 24 couples the oscillating movement of the brake pedal 51 caused by pedal actuation with the translational movement of the (master brake cylinder) piston 15, the actuation travel of which is detected by a travel sensor 25, which preferably has a redundant design. In this way, the corresponding piston travel signal is a measure of the brake pedal actuation angle. It represents the braking desire of the vehicle driver.

[0119] The pressure chamber 17 is connected to a disconnect valve 23 via a hydraulic line 22. The hydraulic connection between the pressure chamber 17 and the brake circuit supply line 13 can be cut off by the disconnect valve 23. A pressure sensor 20 connected to the line section 22 detects the pressure built up in the pressure chamber 17 by the movement of the piston 15. This pressure also represents a measure of the vehicle driver's braking desire.

[0120] The simulator 3 is hydraulically connected to the master brake cylinder 2. The simulator 3 consists essentially of a simulator chamber 29, a simulator rear chamber 30, and a simulator piston 31, which separates the two chambers 29, 30 from each other. The simulator piston 31 is supported on the housing (valve block) by an elastic element 33 (e.g., a simulator spring) arranged in the simulator rear chamber 30. As an example, the simulator chamber 29 can be connected to the pressure chamber 17 of the master brake cylinder 2 via an electrically operable simulator enabling valve 32.

[0121] By way of example, pressure source 5 is activated only by / via second electronic open-loop and closed-loop control unit 12 , since redundancy in the activation of pressure source 5 is not absolutely necessary due to master brake cylinder 2 / hydraulic fallback stage.

[0122] The simulator release valve 32 is assigned to the second electrical section B and is controlled by the second electronic control and regulating unit 12 .

[0123] The pressure sensor 20 and the travel sensor 25 are also assigned to the second electrical section B. The signals from these sensors are fed to the second electronic open-loop control and regulating unit 12 and evaluated and processed by it.

[0124] Already combined Figure 1 (Brake Control Device 100) The remaining components of the brake control device 100' are explained.

[0125] Figure 4 A second exemplary embodiment of a brake system according to the invention is schematically illustrated. Figure 4 The exemplary braking system comprises two hydraulically actuated wheel brakes 8a, 8b and two electromechanically actuated wheel brakes 80a, 80b, and a brake system according to Figure 3 In addition, the system architecture of the second exemplary embodiment corresponds to Figure 2 The system architecture of the first exemplary embodiment of FIG. 1 differs in that no actuating device 300 (and its signal / data connections) is provided, since brake control device 100 ′ comprises a master brake cylinder 2 with a brake pedal 51 .

[0126] A common feature of these exemplary embodiments is that the hydraulic wheel brakes 8a, 8b are connected to the brake control device 100, 100' via two wheel lines 81a, 81b and 82a, 82b, respectively.

[0127] The first wheel lines 81a, 81b are used to build up pressure, which is achieved by the electrically operated pressure source 5 (by pushing the piston 36 forward) via the open inlet valves 6a, 6b (and the closed outlet valves 7a, 7b). In this case, the sequence valve 26 is open and the separation valve 23 is closed.

[0128] The pressure relief for releasing all wheel brakes 8a, 8b (for example for normal braking, for example without anti-lock brake control) is usually achieved by pulling the piston 36 back in the reverse direction, that is, by means of the electrically operated pressure source 5, by pulling the piston 36 back, the pressure medium is sucked into the pressure chamber 37 via the first wheel line 81a, 81b, the open inlet valves 6a, 6b and the open sequence valve 26 (the separation valve 23 is closed).

[0129] In an anti-lock brake control system, ie in the case of wheel-specific pressure regulation, (wheel) pressure relief is achieved by closing the corresponding inlet valve and opening the corresponding outlet valve. This releases the pressure into the pressure medium reservoir 4 via the second wheel lines 82a, 82b.

[0130] This forms (in general) a circulation flow, i.e. pressure medium is conveyed from the pressure medium reservoir 4 into the pressure source 5 (during replenishment), via the inlet valves 6a, 6b and the first wheel lines 81a, 81b into the wheel brakes 8a, 8b, via the second wheel lines (multiple) 82a, 82b and the outlet valves (multiple) 7a, 7b back to the pressure medium reservoir 4. This circulation flow is suitable for regular flushing of the brake control device or the brake system, as well as for the removal of any air bubbles present in the pressure medium reservoir 4.

[0131] This is preferably used for the initial filling / self-filling method of the brake system:

[0132] The brake control device 100, 100' is delivered and installed in the vehicle prefilled with pressure medium (brake fluid) in addition in the pressure medium reservoir 4. The wheel lines 81a, 81b, 82a, 82b and the brake calipers of the wheel brakes 8a, 8b are installed in a dry state (i.e. in an unfilled state). After all connections and electrical energy supply have been made, the brake control device 100, 100' can fill the previously dry wheel lines 81a, 81b, 82a, 82b and wheel brakes 8a, 8b via the circulation explained above.

[0133] The success of the filling can then be checked by means of the angle / position sensor 44 of the pressure source 5 and the pressure sensor 19 , and if necessary an error message can be output if a leak is detected.

[0134] The brake calipers of the wheel brakes 8a, 8b and their connections to the wheel lines and the installation positions of the connections (pressure-building wheel connections 61a, 61b and pressure-relieving wheel connections 62a, 62b) should be designed so that the pressure medium is supplied at the geometrically lower region (pressure-building wheel connections 61a, 61b) and discharged via the geometrically upper region (pressure-relieving wheel connections 62a, 62b), so that no air pockets remain in the brake calipers. It is not necessary to install ventilation screws on the brake calipers.

[0135] Preferably, in particular for self-filling, the following method steps are performed:

[0136] Flushing wheel brakes, for example wheel brake 8b (FR) (first flushing cycle):

[0137] a) Open the sequence valve 26, close the isolating valve 23, and open the outlet valve 7b assigned to the wheel brake.

[0138] b) Actuating the piston 36 of the pressure source 5 (in the forward direction / brake actuation direction).

[0139] The pressure medium volume is thus displaced through the open inlet valve 6 b , the first wheel line 81 b , the wheel brake (brake caliper) 8 b , the second wheel line 82 b , the open outlet valve 7 b in the direction of the pressure medium reservoir 4 .

[0140] c) When the piston 36 of the pressure source 5 reaches the front end ( Figure 1 , Figure 3 When the right end in (this can be monitored by the angle sensor 44 or the displacement sensor around the piston 36), the sequential valve 26 is closed, the piston 36 of the pressure source 5 is retracted (i.e., opposite to the brake operation direction), and the pressure medium is thereby replenished from the pressure medium reservoir 4 into the pressure chamber 37.

[0141] d) Repeat steps a) to c) as many times as necessary.

[0142] Flushing other wheel brakes, such as wheel brake 8a (FL) (second flushing cycle):

[0143] a) Open the sequence valve 26, close the isolating valve 23, and open the outlet valve 7a assigned to the wheel brake.

[0144] b) Actuating the piston 36 of the pressure source 5 (in the forward direction / brake actuation direction).

[0145] The pressure medium volume is thus displaced through the open inlet valve 6a , the first wheel line 81a , the wheel brake (brake caliper) 8a , the second wheel line 82a , the open outlet valve 7a in the direction of the pressure medium reservoir 4 .

[0146] c) When the piston 36 of the pressure source 5 reaches the front end ( Figure 1 , Figure 3 When the right end in (this can be monitored by the angle sensor 44 or the displacement sensor around the piston 36), the sequential valve 26 is closed, the piston 36 of the pressure source 5 is retracted (opposite to the brake operation direction), and the pressure medium is thereby replenished from the pressure medium reservoir 4 into the pressure chamber 37.

[0147] d) Repeat steps a) to c) as many times as necessary.

[0148] Preferably, for the sealing inspection, the following method steps are performed:

[0149] a) Close the separation valve 23, open the sequence valve 26, and keep all other valves (6a, 6b, 7a, 7b; 32 if necessary) de-energized (ie, the inlet valve is open and the outlet valve is closed).

[0150] b) Building up a test pressure of, for example, 100 bar (by means of the pressure source 5 ). In particular, the displacement pressure medium volume required to reach the test pressure is determined.

[0151] c) Wait for the (short) stabilization time.

[0152] d) Start of the measurement phase.

[0153] At least one of the following variables is monitored by one of the sensors of the brake control device: pressure medium volume change (eg monitored by angle / position sensor 44 of pressure source 5 ), pressure drop (eg monitored by pressure sensor 19 ).

[0154] During the specified measuring time, the pressure medium volume should not change.

[0155] Alternatively, at a constant pressure medium volume, no pressure drop should occur or the pressure drop should be balanced with a specified test value / comparison value.

[0156] The displaced pressure medium volume required to reach the check pressure is compared with the specified value.

[0157] e) Complete the sealing inspection.

[0158] The self-filling method is accomplished by releasing the brake system.

[0159] In addition to self-filling, the brake control device according to the invention or the brake system according to the invention allows further operating methods which restore or improve the functionality of the brake control device or the brake system (eg active pressure medium cooling, self-ventilation).

[0160] When descending a slope (for example when descending the Großglockner), the wheel brakes are subject to high thermal loads. If an overheating of the pressure medium (brake fluid) is suspected, a corresponding flushing process / flushing cycle is advantageously carried out as in the case of self-filling to actively cool the pressure medium. If the driver is not currently braking, the same flushing process / flushing cycle (steps a) to c)) is preferably carried out for pressure medium cooling. If the driver is braking continuously, the flushing process / flushing cycle is embedded in the braking process. For example, the pressure medium circulation can be superimposed on normal braking, similar to the anti-lock brake control.

[0161] The following method steps are preferably performed, in particular in driving situations which lead to thermal loading of the wheel brakes (active pressure medium cooling):

[0162] The thermal load is monitored and identified by means of a brake temperature model and optionally also by means of existing sensors arranged in the electromechanical wheel brakes (eg force sensors with temperature output).

[0163] If it is determined that the pressure medium is overheated, a flushing cycle is performed. Alternatively, both wheel brakes can be subjected to a flushing process / flushing cycle simultaneously or one after the other. In this case, the heated pressure medium is directed away from one or more hydraulically actuated wheel brakes 8a, 8b (away from the brake caliper) (via the second wheel line 82a, 82b) to the pressure medium reservoir 4 (see flushing cycle steps a), b). New cold pressure medium flows in from the pressure medium reservoir 4 (see flushing cycle step c). This can avoid the formation of steam bubbles or prevent the formation of steam bubbles.

[0164] To improve the effect, it is advantageous to provide the second wheel lines 82 a , 82 b with enlarged surfaces (eg cooling fins) or to form a radiator.

[0165] If a flushing process / flushing cycle is performed during braking, the braking torque at the electromechanically actuated wheel brakes 80a, 80b (e.g. of the rear axle) is increased for compensation purposes by the amount of the braking torque at the hydraulically actuated wheel brakes 8a, 8b (e.g. of the front axle) that was missing during the flushing cycle. This means that the driver will not notice any change in deceleration.

[0166] Alternatively, the flushing process / flushing cycle can be carried out in a tactile manner so that the driver receives feedback about the dangerous situation. For example, the missing braking torque of the hydraulically actuated wheel brakes during the flushing cycle is not compensated by increasing the braking torque at the electromechanically actuated wheel brakes 80a, 80b.

[0167] The above-described active pressure medium cooling method offers the advantage that brake fluid replacement can be omitted or delayed, or that wheel brakes 8 a , 8 b can have less reserve in terms of thermal design, which can reduce costs.

[0168] The flushing cycle described above is also a ventilation cycle (self-venting) that may be performed by the brake system / brake control device regularly (eg according to a predetermined time schedule) and / or when certain conditions exist (eg after a multi-volume absorption is measured).

[0169] For example, if vapor bubbles form in the switched-off state after a previous thermal load (so-called heat soak), it is not necessary to carry out workshop ventilation after activating the brake system, because the brake system / brake control system automatically performs ventilation by carrying out a flushing cycle.

[0170] With the brake control device according to the invention or the brake system according to the invention, a brake fluid change in a workshop is also simplified. It is only necessary to remove the old brake fluid (old pressure medium) from the second chamber / return chamber 4b of the pressure medium reservoir 4 during a flushing cycle and fill the first chamber / LAC chamber 4a of the pressure medium reservoir 4 with new brake fluid (new pressure medium). Advantageously, the change cycle is performed via a level warning device.

[0171] The advantage provided by the brake control device 100, 100' according to the present invention is that the brake control device can be delivered to the vehicle manufacturer in a pre-filled state, the vehicle manufacturer installs the brake control device in the vehicle when the wheel lines (81, 82) and the wheel brake calipers (wheel brakes 8a, 8b) are not yet filled, and after the brake system is installed and started, the brake system or the brake control device performs a self-filling process.

Claims

1. A hydraulic electronic brake control device (100, 100') for hydraulically actuatable wheel brakes (8a, 8b), the hydraulic electronic brake control device having an electrically controllable hydraulic pressure source (5), an inlet valve (6a, 6b) for each hydraulically actuatable wheel brake (8a, 8b), an outlet valve (7a, 7b) for each hydraulically actuatable wheel brake (8a, 8b), and a pressure medium reservoir (4), characterized in that For at least one of the hydraulically actuatable wheel brakes (8a, 8b), a brake control device (100, 100') has a pressure-building wheel connection (61a, 61b) and a pressure-relieving wheel connection (62a, 62b).

2. The hydraulic electronic brake control device (100, 100') according to claim 1, characterized in that: For at least one of the hydraulically operable wheel brakes (8a, 8b), a pressure-building wheel connection (61a, 61b) is connected to an electrically controllable hydraulic pressure source (5) via an inlet valve (6a, 6b) assigned to the hydraulically operable wheel brake (8a, 8b), and a pressure-relieving wheel connection (62a, 62b) is connected to a pressure medium reservoir (4) via an outlet valve (7a, 7b) assigned to the hydraulically operable wheel brake (8a, 8b).

3. The hydraulic electronic brake control device (100, 100') according to claim 1 or 2, characterized in that: For each hydraulically actuable wheel brake (8a, 8b), a brake control device (100, 100') has a pressure-building wheel connection (61a, 61b) and a pressure-relieving wheel connection (62a, 62b). For each hydraulically actuable wheel brake (8a, 8b), the pressure-building wheel connection (61a, 61b) is connected to an electrically controllable hydraulic pressure source (5) via an inlet valve (6a, 6b) assigned to the corresponding hydraulically actuable wheel brake (8a, 8b), and the pressure-relieving wheel connection (62a, 62b) is connected to a pressure medium reservoir (4) via an outlet valve (7a, 7b) assigned to the corresponding hydraulically actuable wheel brake (8a, 8b).

4. The hydraulic electronic brake control device (100, 100') according to any one of the preceding claims, characterized in that: The electrically controllable hydraulic pressure source (5) is formed by a cylinder-piston arrangement having a pressure chamber (37) and a piston (36), wherein the piston (36) can be moved back and forth by an electromechanical actuator (35, 39).

5. The hydraulic electronic brake control device (100, 100') according to any one of the preceding claims, characterized in that: An electrically controllable hydraulic pressure source (5) is connected via an electrically actuatable sequence valve (26) to a brake line section (13) connected to the inlet valves (6a, 6b).

6. The hydraulic electronic brake control device (100, 100') according to claim 5, characterized in that: The brake line section (13) can be connected to a pressure medium reservoir (4) via an electrically actuatable isolating valve (23).

7. The hydraulic electronic brake control device (100, 100') according to any one of the preceding claims, characterized in that: The pressure medium reservoir (4) has a first reservoir chamber (4a) and a second reservoir chamber (4b) separated from each other by a partition, wherein an electrically controllable hydraulic pressure source (5) is connected to the first reservoir chamber (4a) of the pressure medium reservoir (4) via a replenishing line (42) and a check valve (53) that opens in the direction of the pressure source, and a pressure relief wheel connection (62a, 62b) is connected to the second reservoir chamber (4b).

8. A braking system for a motor vehicle, the braking system having at least two hydraulically actuatable wheel brakes (8a, 8b) and a hydraulic-electronic brake control device (100, 100'), the hydraulic-electronic brake control device comprising an electrically controllable hydraulic pressure source (5), an inlet valve (6a, 6b) for each hydraulically actuatable wheel brake (8a, 8b), an outlet valve (7a, 7b) for each hydraulically actuatable wheel brake (8a, 8b), and a pressure medium reservoir, characterized in that For each hydraulically actuatable wheel brake (8a, 8b), a brake control device (100, 100') is connected to the hydraulically actuatable wheel brake (8a, 8b) via a first hydraulic connecting element (81a, 81b) and a second hydraulic connecting element (82a, 82b).

9. The braking system according to claim 8, characterized in that The brake control device (100, 100') has a pressure-building wheel connection (61a, 61b) and a pressure-relieving wheel connection (62a, 62b) for each hydraulically actuatable wheel brake (8a, 8b).

10. The braking system according to claim 8 or 9, characterized in that: For each hydraulically actuatable wheel brake (8a, 8b), a first hydraulic connecting element (81a, 81b) connects an inlet valve (6a, 6b) assigned to the hydraulically actuatable wheel brake (8a, 8b) to a pressure connection (801a, 801b) of the hydraulically actuatable wheel brake (8a, 8b), and for each hydraulically actuatable wheel brake (8a, 8b), a second hydraulic connecting element (82a, 82b) connects an outlet valve (7a, 7b) assigned to the hydraulically actuatable wheel brake (8a, 8b) to a discharge connection (802a, 802b) of the hydraulically actuatable wheel brake (8a, 8b).

11. The brake system according to any one of claims 8 to 10, characterized in that The brake control device (100, 100') is the brake control device according to any one of claims 1 to 7.

12. A braking system as claimed in any one of claims 8 to 11, comprising at least one wheel brake (80a, 80b) which can be actuated by an electromechanical actuator, in particular comprising two wheel brakes (80a, 80b) which can each be actuated by an electromechanical actuator.

13. The braking system according to claim 12, characterized in that The braking system comprises two wheel brakes (80a, 80b) which can be respectively operated by an electromechanical actuator, wherein one wheel brake (80a) of the wheel brakes which can be operated by the electromechanical actuator is supplied with electric energy by a first power supply (PWR1), and the other wheel brake (80b) which can be operated by the electromechanical actuator is supplied with electric energy by a second power supply (PWR2) which is independent of the first power supply (PWR1).

14. A method for operating a brake system according to any one of claims 8 to 13, characterized in that A flushing cycle is performed by means of a brake control device (100, 100'), in which the c) by operating an electrically controllable hydraulic pressure source (5), in particular in a brake actuation direction, the pressure medium is moved through a first inlet valve of the inlet valves (6a, 6b), through a first hydraulically actuable wheel brake (8a, 8b) assigned to the first inlet valve, through an outlet valve assigned to the first hydraulically actuable wheel brake into the pressure medium reservoir (4) or in the direction of the pressure medium reservoir (4), in particular subsequently, d) by actuating the electrically controllable hydraulic pressure source (5), in particular actuating the electrically controllable hydraulic pressure source in the opposite direction to the brake actuation direction, pressure medium is sucked from the pressure medium reservoir (4) into the electrically controllable hydraulic pressure source (5), In particular, steps a) and b) are repeated cyclically.

15. The method according to claim 14, characterized in that The method is first carried out for one of the hydraulically actuatable wheel brakes (8b) and then for the other of the hydraulically actuatable wheel brakes (8a).

16. The method according to claim 15, characterized in that A leak test is then carried out on the brake system by means of the brake control device (100, 100'), during which a test pressure is built up and maintained by means of an electrically controllable hydraulic pressure source (5).

17. The method according to any one of claims 14 to 16, characterized in that In step a), before operating the electrically controllable hydraulic pressure source (5), in particular before operating the electrically controllable hydraulic pressure source in the brake actuation direction, a sequence valve (26) arranged between the electrically controllable hydraulic pressure source (5) and the inlet valve (6a, 6b) is opened, a separation valve (23) arranged between the inlet valve (6a, 6b) and the pressure medium reservoir (4) is closed, and an outlet valve assigned to the first hydraulically actuable wheel brake is opened.

18. The method according to any one of claims 14 to 17, characterized in that When the piston (36) of the electrically controllable hydraulic pressure source (5) reaches a predetermined end point in the brake actuation direction, step a) is terminated; and the sequence valve (26) is closed before step b) is started.

19. The method according to any one of claims 14 to 18, characterized in that The method is carried out after the installation of the brake system, in particular for filling hydraulically actuatable wheel brakes with pressure medium.

20. The method according to any one of claims 14 to 18, characterized in that The method is performed, in particular for cooling the pressure medium, if it is determined according to a monitoring method that the brake system or one of the wheel brakes (8a, 8b, 80a, 80b) is thermally loaded.

21. The method according to claim 20, characterized in that The monitoring method is carried out based on a brake temperature model and / or based on sensor data, in particular based on data of a force sensor having a temperature output.

22. The method according to any one of claims 14 to 18, characterized in that The method is repeated and / or performed when predetermined conditions are present, in particular to ventilate a brake control device (100, 100').

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