Brake control device, brake system, and method for operating a brake system

Abstract

The present invention relates to an electrohydraulic brake control device (100, 100') for hydraulically actuable wheel brakes (8a, 8b), the brake control device comprising an electrically controllable hydraulic source (5), inlet valves (6a, 6b) for each of the hydraulically actuable wheel brakes (8a, 8b), outlet valves (7a, 7b) for each of the hydraulically actuable wheel brakes (8a, 8b), and a pressure medium reservoir (4), the brake control device (100, 100') comprising a pressure increase wheel connection (61a, 61b) and a pressure decrease wheel connection (62a, 62b) for at least one of the hydraulically actuable wheel brakes (8a, 8b). The present invention also relates to a brake system for a motor vehicle, the brake system comprising at least two hydraulically actuable wheel brakes (8a, 8b), an electrically controllable hydraulic source (5), inlet valves (6a, 6b) for each of the hydraulically actuable wheel brakes (8a, 8b), outlet valves (7a, 7b) for each of the hydraulically actuable wheel brakes (8a, 8b), and an electrohydraulic brake control device (100, 100') comprising a pressure medium reservoir, the brake control device (100, 100') for each of the hydraulically actuable wheel brakes (8a, 8b) being connected to the hydraulically actuable wheel brakes (8a, 8b) via first and second hydraulic connection elements (81a, 82a, 81b, 82b). The present invention further relates to a method for operating a brake system of this type.

Description

Technical Field

[0001] The present 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.

Background Art

[0002] German Patent Application Publication No. 102015001541 A1 discloses a hydraulically actuated wheel brake having a brake disc, a brake caliper, and brake pads. The brake pads can be filled with brake fluid and expand during the braking phase. In the process, the brake pads are pressed against the brake disc, have a chamber, and have an inlet formed on the brake pads for introducing brake fluid into the chamber. The brake pads have a return port separate from the inlet for removing brake fluid from the chamber. The brake system is designed such that the brake fluid can be circulated through the chamber via the inlet and the return port by a conveying unit to cool the brake pads.

[0003] An electrohydraulic brake control device and a by-wire brake system having four hydraulically actuable wheel brakes are known from WO 2018 / 130393 A1 pamphlet. The brake control device comprises a master brake cylinder, an electrically controllable pressure source, and exactly four hydraulic wheel connections for four hydraulically actuable wheel brakes. Each of the four hydraulically actuable wheel brakes has a single connection that is connected to exactly one of the four hydraulic wheel connections of the electrohydraulic brake control device.

[0004] A so-called composite by-wire brake system having a master brake cylinder and an electro-hydraulic brake control device with an electrically controllable pressure source, two hydraulically actuable wheel brakes, and two wheel brakes each actuable by an electromechanical actuator is known from German Patent Application Publication No. 102012217825A1. Each of the two hydraulically actuable wheel brakes has a single connection that is connected to exactly one of exactly two hydraulic wheel connections of the electro-hydraulic brake control device.

[0005] Such a by-wire brake system must be filled with brake fluid (pressure medium) using a filling device in the manufacturer's factory of an automobile manufacturer and, if necessary, emptied appropriately.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The object of the present invention is to provide an electro-hydraulic brake control device for a by-wire brake system and a by-wire brake system that enables self-filling, i.e., filling of the pressure medium without an additional filling device, thereby avoiding time-consuming and error-prone processes in the manufacturer's factory of an automobile manufacturer.

[0007] This object is achieved by the electro-hydraulic brake control device according to claim 1 and the brake system according to claim 8.

[0008] A further object of the present invention is to provide a method for operating a brake system that generates, restores, or improves the function of the brake system.

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

Means for Solving the Problems

[0010] The concept of the present invention regarding an electro-hydraulic brake control device is based on the fact that an electro-hydraulic brake control device for a hydraulically actuable wheel brake comprises an electrically activatable hydraulic source, an inlet valve for each of the hydraulically actuable wheel brakes, an outlet valve for each of the hydraulically actuable wheel brakes, and a pressure medium reservoir. For at least one of the hydraulically actuable wheel brakes, the brake control device has a pressure build-up wheel connection and a pressure release wheel connection. This means that the brake control device has two separate wheel connections, namely a pressure build-up wheel connection and a pressure release wheel connection, for at least one of the hydraulically actuable wheel brakes.

[0011] The brake control device has the advantage that a brake control device that is automatically electrically controlled by a suitable activation of the electrically activatable pressure source and by inlet and outlet valves for at least one of the hydraulically actuable wheel brakes can convey the pressure medium from the electrically activatable pressure source to the pressure medium reservoir via the inlet valve of the wheel brake, the pressure build-up wheel connection, the wheel brake, and the pressure release wheel connection. This enables self-filling or other purging of the wheel brakes by the brake system itself when the brake system is installed in a vehicle.

[0012] Preferably, for at least one of the hydraulically actuable wheel brakes, the pressure build-up wheel connection is connected to the electrically activatable hydraulic source via the inlet valve assigned to the hydraulically actuable wheel brake, and the pressure release wheel connection is connected to the pressure medium reservoir via the outlet valve assigned to the hydraulically actuable wheel brake.

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

[0014] The brake control device is preferably designed specifically for exactly two hydraulically actuable wheel brakes. In that case, the brake control device comprises two inlet valves and two outlet valves for two hydraulically actuable wheel brakes. Particularly preferably, the brake control device comprises (exactly) two pressure build-up wheel connections and two pressure release wheel connections, wherein the first pressure build-up wheel connection is connected via the first inlet valve to an electrically activatable hydraulic fluid source, the first pressure release wheel connection is connected via the first outlet valve to a pressure medium reservoir, the second pressure build-up wheel connection is connected via the second inlet valve to an electrically activatable hydraulic fluid source, and the second pressure release wheel connection is connected via the second outlet valve to a pressure medium reservoir. Particularly preferably, the first inlet valve is connected via the first pressure build-up wheel connection and a first hydraulic connection element to the pressure port of the first hydraulically actuable wheel brake, the first outlet valve is connected via the first pressure release wheel connection and a second hydraulic connection element to the drain port of the first hydraulically actuable wheel brake, the second inlet valve is connected via the second pressure build-up wheel connection and a further first hydraulic connection element to the pressure port of the second hydraulically actuable wheel brake, and the second outlet valve is connected via the second pressure release wheel connection and a further second hydraulic connection element to the drain port of the second hydraulically actuable wheel brake.

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

[0016] According to a preferred embodiment, the brake control device for each of the hydraulically actuable wheel brakes in each case has a pressure build-up wheel connection and a pressure release wheel connection, and for each of the hydraulically actuable wheel brakes, in each case the pressure build-up wheel connection is connected via an inlet valve assigned to the respective hydraulically actuable wheel brake to an electrically actuable hydraulic source, and the pressure release wheel connection is connected via an outlet valve assigned to the respective hydraulically actuable wheel brake to a pressure medium reservoir. This means that the electro-hydraulic brake control device has two (separate) wheel connections for each of the hydraulically actuable wheel brakes. For each of the hydraulically actuable wheel brakes, there is a pressure build-up wheel connection for supplying the pressure medium from the electrically actuable pressure source via the brake control device inlet valve assigned to the corresponding wheel brake to the corresponding wheel brake, and a pressure release wheel connection for discharging the pressure medium from the corresponding wheel brake via the brake control device outlet valve assigned to the corresponding wheel brake to the pressure medium reservoir. This brake control device has the advantage that a brake control device that is automatically electrically controlled by a suitable activation of the electrically actuable pressure source and the inlet and outlet valves for each of the hydraulically actuable wheel brakes can convey the pressure medium from the electrically actuable pressure source to the pressure medium reservoir via the inlet valve of the corresponding wheel brake, the associated pressure build-up wheel connection, the corresponding wheel brake, and the associated pressure release wheel connection. This enables self-filling or otherwise purging of all of the wheel brakes or the entire brake system by the brake system itself when the brake system is installed in a vehicle.

[0017] Thus, if an electro-hydraulic brake control device is designed for two hydraulically actuable wheel brakes, the brake control device preferably has two pressure build-up wheel connections and two pressure release wheel connections, and thus a total of four separate wheel connections for connecting two hydraulically actuable wheel brakes. The two pressure build-up wheel connections are provided, in particular, to increase the pressure of each wheel brake by an electrically actuable pressure source via the inlet valve assigned to each wheel brake, and the two pressure release wheel connections are provided, in particular, to release the pressure of each wheel brake to a pressure medium reservoir via the outlet valve assigned to each wheel brake.

[0018] Thus, if an electro-hydraulic brake control device is designed for four hydraulically actuable wheel brakes, the brake control device preferably has four pressure build-up wheel connections and four pressure release wheel connections, i.e., a total of eight separate 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 connection line is provided between the wheel brake side connection of the inlet valve of the corresponding hydraulically actuable wheel brake and the wheel brake side connection of the outlet valve of the corresponding hydraulically actuable wheel brake within the brake control device.

[0020] Preferably, in addition to the electrically actuable hydraulic source, the electro-hydraulic brake control device does not comprise any other hydraulic source. The brake control device particularly preferably does not comprise a master brake cylinder actuable by a brake pedal for actuating the wheel brakes at a hydraulic fallback level. The brake control device also particularly preferably does not comprise a second electrically actuable hydraulic source.

[0021] Preferably, the electrically activatable hydraulic source is formed by a cylinder-piston device having a pressure chamber and a piston, and the piston can be pushed back and forth by an electromechanical actuator. This means that it is possible both to push the pressure medium into the wheel brake and to suck it up from the wheel brake. The piston moves forward (in the operating direction of the brake) to increase the brake pressure and moves backward (i.e., in the direction opposite to the operating direction of the brake) to release the brake pressure. The piston also moves backward (i.e., in the direction opposite to the operating direction of the brake) to replenish the pressure medium from the pressure medium reservoir to the pressure source.

[0022] Preferably, the electrically activatable hydraulic source, in particular its pressure chamber, is connected via an electrically operable activation valve to a brake line section to which the inlet valve of the brake control device is connected. Particularly preferably, the activation valve is configured to be normally closed. By means of the activation 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 operable isolation valve. This makes it possible to hydraulically connect the inlet valve to the pressure medium reservoir, thereby reducing the pressure in the wheel brake. Particularly preferably, the isolation valve is configured to be normally open, and thus, in the non-operating blocked state of the brake control device or the brake system, the wheel brake is hydraulically connected to the pressure medium reservoir.

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

[0025] According to another preferred embodiment, the brake line section is connected via a separating valve and a line section to the pressure chamber of the master brake cylinder. The pressure chamber of the master brake cylinder is connected, particularly preferably, to the pressure medium reservoir via one or more breather holes when the master brake cylinder piston is not actuated. This hydraulic connection between the pressure chamber and the pressure medium reservoir is separated when the master brake cylinder piston actuates (sufficiently) in the actuating direction.

[0026] The pressure source is preferably formed by a cylinder-piston device having a hydraulic pressure chamber, a suction port, and a pressure port, the piston of which can move back and forth or can be pushed back and forth by an electromechanical actuator. The suction port is particularly preferably connected to the pressure medium reservoir via a replenishment line having a check valve that opens in the flow direction towards the pressure chamber. The pressure connection is preferably connected to the brake line section via an activation valve.

[0027] Preferably, the pressure medium reservoir has two reservoir chambers separated by a partition wall, and 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 activatable hydraulic pressure source is connected to the other reservoir chamber. This enables, in particular, self-venting (or purging) of the brake control device during pressure medium replacement (brake fluid replacement) at the workplace or, particularly preferably, while the vehicle is in operation. For example, if vapor bubbles are generated in the brake system as a result of reheating while the vehicle is stationary, this can be detected by an increased volume uptake in the brake system test routine after the vehicle has been parked. As a result, a self-venting cycle is then initiated, the pressure medium reservoir acts as a gas bubble separator, and the separation into the two reservoir chambers prevents the foamed pressure medium (brake fluid) from being sucked up again.

[0028] The concept of the present invention regarding the braking system is based on the fact that the braking system comprises at least two hydraulically actuatable wheel brakes and an electro-hydraulic brake control device, and the electro-hydraulic brake control device comprises an electrically activatable hydraulic 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 first and second (i.e., separate) hydraulic connection elements. This means that the braking system has two separate hydraulic connection elements for each hydraulically actuatable wheel brake, namely 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 braking system has the advantage that, for each wheel brake, the pressure medium from the brake control device can be directed to the hydraulically actuatable wheel brake via the first hydraulic connection element, and the pressure medium can be separately redirected from the wheel brake to the brake control device via the second hydraulic connection element. Thus, self-filling or purging of the wheel brakes by the braking system is possible by activation of the preferably, advantageously automatically, electrically activatable pressure source.

[0030] Preferably, the brake control device for each of the hydraulically actuable wheel brakes has a pressure increase wheel connection and a pressure release wheel connection. Particularly preferably, for each of the hydraulically actuable wheel brakes, the pressure increase wheel connection is connected to an electrically actuable hydraulic source via an inlet valve assigned to the (respective) hydraulically actuable wheel brake, and the pressure release 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, the pressure medium can be guided from the brake control device, via the pressure increase wheel connection and the first hydraulic connection element, to the hydraulically actuable wheel brake, flowed through the wheel brake, and discharged to the brake control device via the second hydraulic connection element and the pressure release wheel connection.

[0031] Preferably, for each of the hydraulically actuable wheel brakes, the first hydraulic connection element connects an inlet valve assigned to the hydraulically actuable wheel brake, particularly preferably, via a brake control device pressure increase wheel connection assigned to the inlet valve, to a pressure port of the hydraulically actuable wheel brake. This connection is particularly suitable for increasing the pressure in the hydraulically actuable wheel brake by the hydraulic source.

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

[0033] Preferably, the brake control device is designed as an electro-hydraulic brake control device according to the present invention.

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

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

[0036] The braking system preferably comprises exactly two hydraulically actuatable wheel brakes. Particularly preferably, these are assigned to the 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 development form of the braking system, the braking system comprises two hydraulically actuatable wheel brakes, an electrohydraulic brake control device, and two electromechanically actuatable wheel brakes. The braking system particularly preferably comprises exactly two hydraulically actuatable wheel brakes.

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

[0039] Preferably, the braking system is designed to determine an actuation signal that quantifies a braking demand as a result of actuation by a vehicle driver, and comprises an actuation device connected to an electro-hydraulic braking control device via a signal connection or a data connection for transmitting the actuation signal. Particularly preferably, the actuation device is in the form of an electric brake pedal (ePedal). Particularly preferably, there is no mechanical hydraulic connection from the actuation device to the brake control device or to the hydraulically actuable wheel brakes.

[0040] Preferably, the electro-hydraulic braking control device comprises a first electronic control and adjustment unit and a second electronic control and adjustment unit, the electrically activatable hydraulic source is activated by the second electronic control and adjustment unit, and the inlet and outlet valves are activated by the first electronic control and adjustment unit.

[0041] Preferably, the electrically activatable hydraulic source is separably hydraulically connected to the inlet valve via an electrically actuable activation valve, and the activation valve is activated by the second electronic control and adjustment unit.

[0042] The isolation valve between the brake line section and the pressure medium reservoir is preferably activated by the second electronic control and adjustment unit.

[0043] Preferably, the braking system comprises a first electrical compartment and a second electrical compartment, and the second electrical compartment is independent of the first electrical compartment.

[0044] Preferably, the first electronic control and adjustment unit of the electro-hydraulic braking control device or the first electrical compartment of the braking system is supplied by a first electrical energy source, and the second electronic control and adjustment unit of the electro-hydraulic braking control device or the second electrical compartment of the braking system is supplied by a second electrical energy source independent of the first electrical energy source. Thus, the first energy source is part of the first electrical compartment and the second energy source is part of the second electrical compartment.

[0045] Preferably, the braking system comprises two wheel brakes each operable by an electromechanical actuator, one of the wheel brakes operable by the electromechanical actuator belonging to a first electrical compartment of the braking system and the other of the wheel brakes operable by the electromechanical actuator belonging to a second electrical compartment of the braking system.

[0046] Preferably, the braking system comprises two wheel brakes (i.e., two electromechanically operable wheel brakes) each operable by an electromechanical actuator, one of the wheel brakes operable by the electromechanical actuator being supplied with electrical energy by a first electrical energy source and the other wheel brake operable by the electromechanical actuator being supplied with electrical energy by a second electrical energy source independent of the first electrical energy source. The brake control device is particularly preferably supplied with electrical energy by the first and second electrical energy sources. Very particularly preferably, the second electronic control and adjustment unit of the brake control device and the electrically activatable hydraulic source are supplied with electrical energy by the first electrical energy source and the first electronic control and adjustment unit, and the inlet valve and the outlet valve are supplied with electrical energy by the second electrical energy source.

[0047] Preferably, the braking system comprises two electromechanically operable wheel brakes, each of the electromechanically operable wheel brakes comprising a separate electronic control and adjustment unit for activating the electromechanical actuator of the electromechanically operable wheel brake.

[0048] Preferably, the braking 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 the first electronic control and adjustment unit of the electrohydraulic brake control device to the two electronic control and adjustment units of the electromechanically actuable wheel brakes.

[0050] Preferably, the second data bus connects the first electronic control and adjustment unit of the electrohydraulic brake control device to the two electronic control and adjustment units of the electromechanically actuable wheel brakes.

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

[0052] Preferably, each of the two electronic control and adjustment units for activating one of the electromechanical actuators of the electromechanically actuable wheel brakes is connected to the first data bus and the second data bus. This results in the advantage of a redundant supply of the driver's braking demand to the two electromechanically actuable wheel brakes.

[0053] Preferably, the first data bus connects the second electronic control and adjustment unit of the electrohydraulic brake control device to the two electronic control and adjustment units of the electromechanically actuable wheel brakes.

[0054] Preferably, each hydraulically actuatable wheel brake of the braking system comprises a pressure medium chamber for actuating the brake element, and the pressure medium chamber is connected to the pressure connection of the wheel brake for supplying the pressure medium from the brake control device or for connection to one of the inlet valves of the brake control device. In either case, the pressure medium chamber of the wheel brake is further connected to the drain port of the wheel brake for discharging the pressure medium to the 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 brake does not have any other vent connection with a drain screw or a vent valve.

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

[0057] The inventive concept regarding the method for operating the braking system according to the invention is based on the fact that the brake control device is used to perform a purge cycle, a) In particular, by actuating the electrically actuable hydraulic source in the operating direction of the brake, the pressure medium moves through the first inlet valve of the inlet valve, through the first hydraulically actuatable wheel brake assigned to the first inlet valve, and through the outlet valve assigned to the first hydraulically actuatable wheel brake, into the pressure medium reservoir or in the direction of the pressure medium reservoir. In particular, then, b) In particular, by actuating the electrically actuable hydraulic source in the direction opposite to the operating direction of the brake, the pressure medium is sucked from the pressure medium reservoir into the electrically actuable hydraulic source. In particular, steps a) and b) are repeated periodically.

[0058] Preferably, the pressure medium reservoir of the braking system has a first reservoir chamber and a second reservoir chamber, the reservoir chambers being separated from each other by a partition wall, the outlet valve being connected to the second reservoir chamber, and the replenishment line of the electrically activatable hydraulic source being connected to the first reservoir chamber. In step a), the pressure medium is conveyed to the second reservoir chamber, and in step b), the pressure medium is sucked from the first reservoir chamber into the pressure source. For example, a brake fluid change (pressure medium change) can be easily carried out at the workplace by removing the old pressure medium from the second reservoir chamber of the pressure medium reservoir and filling the first reservoir chamber of the pressure medium reservoir with the new pressure medium.

[0059] The method is preferably carried out first for one of the hydraulically actuatable wheel brakes and then for another hydraulically actuatable wheel brake. Particularly preferably, the leak test of the braking system is then carried out by the brake control device, in which the test pressure is increased and maintained by the electrically activatable hydraulic source.

[0060] Preferably, in step a), in particular before the electrically activatable hydraulic source is actuated in the operating direction of the brake, the start valve of the electrohydraulic brake control device is opened, the isolation valve of the electrohydraulic brake control device is closed, and the outlet valve assigned to the first hydraulically actuatable wheel brake is opened.

[0061] Preferably, when the piston of the electrically activatable hydraulic source reaches a predetermined end point in the operating direction of the brake, step a) ends and the start valve of the electrohydraulic brake control device is closed before step b) is started.

[0062] Preferably, the method according to the invention is carried out after installation of the braking system. Particularly preferably, the method for filling a hydraulically actuatable wheel brake with a pressure medium is carried out after installation of the braking system. Particularly preferably, the method is carried out in an automobile manufacturing plant.

[0063] Preferably, the method according to the invention for cooling the pressure medium is carried out. Preferably, the method according to the invention is carried out when a thermal load of one of the braking system or the wheel brake is detected based on a monitoring method. Particularly preferably, 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 by means of a temperature output.

[0064] Preferably, the method according to the invention for venting a brake control device is carried out. The method according to the invention is preferably repeated and / or carried out in a predetermined state. Particularly preferably, the method is repeatedly carried out according to a predetermined time schedule.

[0065] Further preferred embodiments of the invention result from the following description with reference to the dependent claims and the figures.

Brief Description of the Drawings

[0066]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0067] Figure 1 schematically shows a first exemplary embodiment of a brake control device 100 according to the present invention. The exemplary electro-hydraulic brake control device 100 is designed to operate two hydraulically actuable wheel brakes 8a, 8b. The brake control device 100 includes an electrically activatable hydraulic source 5, a pressure medium reservoir 4 under atmospheric pressure, and electrically actuable inlet valves 6a, 6b and electrically actuable outlet valves 7a, 7b for the respective wheel brakes 8a, 8b.

[0068] Advantageously, the inlet valves 6a, 6b are normally open and the outlet valves 7a, 7b are normally closed.

[0069] As an example, the brake control device 100 includes a first electronic control and adjustment unit 11 (ECU1) and a second electronic control and adjustment unit 12 (ECU2). Alternatively, the brake control device 100 may also include an electronic control and adjustment unit ECU having, for example, two separate regions in the form of a first printed circuit board (corresponding to 11) and a second printed circuit board (corresponding to 12). In that case, the following applies accordingly to the first and second regions (first and second printed circuit boards) instead of the first and second electronic control and adjustment units 11, 12.

[0070] The brake control device 100 is designed, for example, as an electro-hydraulic unit (HECU) having a hydraulic control and adjustment unit 60 (also called a valve block) and two electronic control and adjustment units 11, 12 (ECU1, ECU2).

[0071] The electrically activatable hydraulic source 5 is designed as a hydraulic cylinder piston device having a pressure chamber 37 and a piston 36 (i.e., an electro-hydraulic actuator (linear actuator) of a single circuit), and its piston 36 can be pushed back and forth by an electric motor 35, which is also schematically shown, to which a rotation-translation mechanism 39, which is schematically illustrated, is interconnected. A rotor position sensor, which serves to detect the rotor position of the electric motor 35, which is only shown schematically, is indicated by reference numeral 44.

[0072] The pressure chamber 37 of the pressure source 5 is connected via an electrically actuatable activation valve 26 to a brake line section 13 to which inlet valves 6a, 6b are connected. The activation valve 26 is advantageously normally closed. For this purpose, the pressure chamber 37 is connected via a system pressure line 38 to the activation valve 26, and the activation valve 26 is connected on the outlet side to the brake line section 13.

[0073] A pressure sensor 19 for determining the system pressure generated by the pressure source 5 is arranged in the brake line section 13.

[0074] To replenish the pressure medium in the pressure source 5, the pressure chamber 37 is connected via a replenishment line 42 to a pressure medium reservoir 4, preferably to the first chamber / LAC chamber 4a of the pressure medium reservoir, via a check valve (replenishment valve) 53 that is open in the flow direction towards the pressure chamber 37. Thus, by closing the activation valve 26 and moving the piston 36 backwards, the pressure medium can flow out from the pressure medium reservoir 4 or, preferably, from the first chamber 4a of the pressure medium reservoir, via the replenishment line 42 to the pressure chamber 37.

[0075] The exemplary brake control device 100 does not comprise a further pressure source in addition to the pressure source 5, i.e., neither a further electrically actuatable pressure source nor a master brake cylinder actuatable by a brake pedal is provided.

[0076] For each of the hydraulically actuable wheel brakes 8a, 8b, the brake control device comprises a pressure build-up wheel connection 61a, 61b and a (separate) pressure release wheel connection 62a, 62b. This means that the two separate wheel connections (61 and 62) are provided for the respective hydraulically actuable wheel brakes 8a, 8b, and that the pressure build-up wheel connections 61a, 61b and the pressure release wheel connections 62a, 62b are not directly connected to each other in the brake control device 100. In particular, the wheel brake side connections of the respective inlet valves 6a, 6b are not connected to the wheel brake side connections of the corresponding outlet valves 7a, 7b via a hydraulic connection (connection line).

[0077] For each of the hydraulically actuable wheel brakes 8a, 8b, an electrically activatable hydraulic source 5 is connected to the pressure build-up wheel connections 61a, 61b via the corresponding inlet valves 6a, 6b assigned to the hydraulically actuable wheel brakes 8a, 8b. For each of the hydraulically actuable wheel brakes 8a, 8b, the pressure release wheel connections 62a, 62b are connected to the pressure medium reservoir 4 via the corresponding outlet valves 7a, 7b assigned to the hydraulically actuable wheel brakes 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 parts). For pressure release by the outlet valves 7a, 7b, a part of the pressure medium discharged via the outlet valves 7a, 7b flows into the pressure medium reservoir 4 via the return line 14 or, preferably, into the second chamber of the pressure medium reservoir.

[0078] Thus, the brake control device 100 for each of the hydraulically actuable wheel brakes 8a, 8b is connected to the hydraulically actuable wheel brakes 8a, 8b via a first hydraulic connection element (first wheel line) 81a, 81b and via a second hydraulic connection element (second wheel line) 82a, 82b.

[0079] The first hydraulic connection element (first wheel line) 81a or 81b is, on the one hand, connected to the pressure increase wheel connection 61a or 61b of the brake control device assigned to the wheel brake 8a or 8b (and thus 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 is used to increase the pressure of the wheel brake by a hydraulic pressure source 5 (for increasing the wheel brake pressure).

[0080] The second hydraulic connection element (second wheel line) 82a, 82b is, on the one hand, connected to the pressure release wheel connection 62a or 62b of the brake control device 100 to which the pressure release wheel connection is assigned to the wheel brake 8a or 8b (and thus connected to the corresponding outlet valve 7a or 7b), and on the other hand, to the drain port (802a or 802b) of the wheel brake 8a or 8b. The release of the pressure medium from the wheel brake 8a or 8b via the second wheel line 82a or 82b is effected via the outlet valve 7a or 7b to the pressure medium reservoir 4 of the brake control device 100 (for releasing the wheel brake pressure).

[0081] Check valves 16a, 16b opening in the direction of the brake circuit supply line 13 are connected in parallel with each of the inlet valves 6a, 6b.

[0082] In order to enable, if necessary, the pressure reduction of the wheel brakes 8a, 8b, i.e., to enable the pressure of the wheel brakes 8a, 8b to be equalized to the atmosphere, the brake line section 13 is connected to the pressure medium reservoir 4 via an electrically actuable isolation valve 23 and a pressure equalization line section 41, preferably to the second chamber / return chamber 4b of the pressure medium reservoir. The isolation valve 23 is advantageously always open, for example, to ensure the pressure equalization of the wheel brake with the atmosphere in the switched-off state when the brake system switch is switched off.

[0083] Advantageously, the level measurement device 50 is arranged to determine the pressure medium level / condition in the pressure medium reservoir 4. Preferably, the level measurement device 50 is arranged in the first chamber / LAC chamber 4a of the pressure medium reservoir.

[0084] For the electrical mounting, connection, and supply of the brake control device 100 or individual electrical or electrically actuable components of the brake system that can perform startup or evaluation (see FIG. 2), a first electrical compartment A and a second electrical compartment B are provided, and they are electrically independent of each other.

[0085] In the figure, those electrical components assigned to or belonging to the first electrical compartment A are indicated by arrows marked with A. Those electrical components assigned to or belonging to the second electrical compartment B are indicated by arrows marked with B.

[0086] The first electronic control and adjustment unit 11 is assigned to or belongs to the first electrical compartment A, while the second electronic control and adjustment unit 12 is assigned to or belongs to the second electrical compartment B. Thus, the electronic control and adjustment unit 11 and the second control and adjustment unit 12 are electrically independent.

[0087] To supply electrical energy to the brake control device 100 or the brake system, a first electrical energy source PWR2, for example, a vehicle electrical system, and a second electrical energy source PWR1, which is independent of the first energy source, for example, a second vehicle electrical system, are provided. The first electrical energy source PWR2 supplies energy to the first electrical compartment A, and the second electrical energy source PWR1 supplies energy to the second electrical compartment B.

[0088] The second electronic control and adjustment unit 12 activates the pressure source 5. Thus, the first pressure source 5 is assigned or associated with the second electrical compartment B. According to an example, the first pressure source 5 is supplied with energy (from the second electrical energy source PWR1) via the second electronic control and adjustment unit 12. According to an example, the first pressure source 5 can be activated exclusively or is activated by the second electronic control and adjustment unit 12.

[0089] To achieve redundancy in the activation of the pressure source 5, both compartments A and B of the brake control device 100 (or the control and adjustment units 11, 12 and both printed circuit boards) are provided according to a preferred embodiment so as to be designed to activate the motor-driven pressure source 5 based on operating information. For this purpose, for example, both compartments A, B (or both control and adjustment units 11, 12 or both printed circuit boards) are connected to the control device of the power electronics of the electric motor 35. In this way, even if one of the compartments A, B fails, the targeted control of the hydraulic pressure of the brake control device 100 is still possible. The pressure source 5 can be activated by the second electronic control and adjustment unit 12 and by the first electronic control and adjustment unit 11.

[0090] The remaining components of the braking system are advantageously assigned to either the first electronic control and adjustment unit 11 (section A) or the second electronic control and adjustment unit 12 (section B). That is, the components are activated, or actuated, and / or supplied with electrical energy, and / or signal-side connected to, and / or evaluated by the control and adjustment unit. To avoid further redundancy, advantageously, the components are activatable or actuatable, or supplyable with electrical energy, or signal-side connectable, or evaluable, by only one of the two electronic control and adjustment units 11, 12, rather than by other electronic control devices, or exclusively by one of the two electronic control and adjustment units 11, 12.

[0091] To enable the activation of the pressure source 5, the rotor position sensor 44 is assigned to the second electrical section B. The signal from the sensor is supplied to the second electronic control and adjustment unit 12 and evaluated and processed by the second electronic control and adjustment unit 12.

[0092] The activation valve 26 and the separation valve 23 are also assigned to the second electrical section B and are activated by the second electronic control and adjustment unit 12.

[0093] Furthermore, the signal from the level measuring device 50 is supplied to the second electronic control and adjustment unit 12 and evaluated and processed by the second electronic control and adjustment unit 12.

[0094] In contrast, the inlet valves 6a to 6d and the outlet valves 7a to 7d are assigned to the first electrical section A and are activated by the first electronic control and adjustment unit 11.

[0095] The pressure sensor 19 is also assigned to the first electrical compartment A. The signal from the sensor is supplied to the first electronic control and adjustment unit 11 and evaluated and processed by the first electronic control and adjustment unit 11.

[0096] Figure 2 schematically shows a first exemplary embodiment of a braking system according to the invention. Figure 2 shows the system architecture of the braking system. The exemplary braking system comprises two hydraulically actuable wheel brakes 8a, 8b and two (also referred to as electromechanically actuable wheel brakes 80a, 80b for short) electromechanically actuable wheel brakes 80a, 80b, each actuable by an electromechanical actuator, and the electrohydraulic brake control device 100 according to Figure 1.

[0097] 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 and electromechanically actuable wheel brakes 8a, 8b, 80a, 80b are designed as service brakes of the vehicle.

[0098] The braking system is connected to an (actuation) device 300 which is designed to determine an actuation signal which quantifies the braking request as a result of actuation by the vehicle driver. The actuation device 300 having a brake pedal 51 is in the form of an electric brake pedal (ePedal). This means that there is no mechanical hydraulic connection from the actuation device 300 to the brake control device 100 or to the hydraulically actuable wheel brakes 8a, 8b. Direct mechanical / hydraulic actuation of the wheel brakes 8a, 8b by the actuation device 300 is not possible. The actuation device 300 is connected to the brake control device 100 via a signal connection or data connection 150 for transmitting the actuation signal.

[0099] The pressure increase wheel connection 61a of the brake control device 100 is hydraulically connected to the pressure port 801a of the wheel brake 8a via the first wheel line 81a, and the pressure release wheel connection 62a of the brake control device 100 is hydraulically connected to the drain port 802a of the wheel brake 8a via the second wheel line 82a. Accordingly, the pressure increase wheel connection 61b of the brake control device 100 is hydraulically connected to the pressure port 801b of the wheel brake 8b via the first wheel line 81b, and the pressure release wheel connection 62b of the brake control device 100 is hydraulically connected to the drain port 802b of the wheel brake 8b via the second wheel line 82b.

[0100] Each of the electromechanically operable wheel brakes 80a, 80b comprises, for example, separate electronic control and adjustment units WCUa, WCUb (WCU: wheel control unit) for activating the corresponding electromechanical actuators of the wheel brakes 80a, 80b.

[0101] The wheel brake 80a is supplied with electrical energy from a second electrical energy source (PWR1) (compartment B), while the wheel brake 80b is supplied with electrical energy from a first electrical energy source (PWR2) (compartment A).

[0102] Each wheel FL, FR, RL, RR is assigned a wheel speed sensor WSS1, WSS2, WSS3, WSS4 (WSS: wheel speed sensor). Signals from the wheel speed sensors WSS3, WSS4 of the wheels having the electromechanically operable wheel brakes 80a, 80b are supplied to the respective electronic control and adjustment units WCU. Signals from the wheel speed sensors WSS1, WSS2 of the wheels having the hydraulically operable wheel brakes 8a, 8b are supplied to the first electronic control and adjustment unit 11.

[0103] Furthermore, the braking 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 to the electronic control and regulation units WCUa, WCUb. The braking system further comprises a second data bus 58 ("brake bus 2"), in particular a CAN bus, which also connects the first electronic control and regulation unit 11 to the electronic control and regulation units WCUa, WCUb.

[0104] Preferably, the electromechanically actuable wheel brakes 80a, 80b are designed to also include a parking brake device.

[0105] Instead of two, for example, spatially separated electronic control and regulation units 11 and 12, a (single) control and regulation unit ECU may be provided, which comprises two electrically independent areas, for example, in the form of two printed circuit boards. In that case, one area, for example, the first printed circuit board is assigned to section A and the other area, for example, the second printed circuit board is assigned to section B.

[0106] The electrohydraulic front axle actuator (brake control device 100) consists of a hydraulic and an electronic control unit (HCU and ECU). The hydraulic front wheel brakes 8a, 8b are each connected to the HCU by a double pipeline (consisting of a first wheel line 81a, b and a second wheel line 82a, b). In each case, one line is used to increase the pressure (first wheel line 81a, b) and one line is used to release the pressure (second wheel line 82a, b).

[0107] The ECU has two compartments, here called compartment A and compartment B. These compartments A and B are independent areas, each having its own microcontroller, which executes a customized software program. Compartments A and B are connected to each other via an internal ECU data bus. Both compartments A and B can preferably access or activate the actuator required for pressure setting by the pressure source 5.

[0108] Compartment A is simply electrically connected (connection 150) to the redundant actuation device 300 (ePedal) and converts the detected driver's braking desire into a corresponding BUS signal for activating the electromechanical rear-wheel brakes 80a, 80b. For redundancy, the actuation device 300 (ePedal) is also simply electrically connected (connection 160) to an external electronic control and adjustment unit (ECU) 400 (of the braking system) and likewise converts the driver's desire into a corresponding BUS signal. Thus, the transmission of the driver's desire to the rear-wheel brakes 80a, 80b (by the first data bus 57 (“in-vehicle bus 1”) or the second data bus 58 (“brake bus 2”)) is still possible even if the brake control device 100 fails completely, for example due to a plug failure.

[0109] Figure 3 schematically shows a second exemplary embodiment of the brake control device 100' according to the present invention. In contrast to the first exemplary embodiment of Figure 3, the brake control device 100' has a hydraulic fallback level by means of the driver's access to the wheel brakes 8a, 8b. For this purpose, the brake control device 100' comprises a master brake cylinder 2 operable by the brake pedal 51 and a simulation device 3 interacting with the master brake cylinder 2.

[0110] The master brake cylinder 2 has a piston 15 in a housing (formed by a valve block) bounding the pressure chamber 17. In the non-operating state of the master brake cylinder 2 / piston 15, the pressure chamber 17 is connected to the pressure medium reservoir 4 via a radial bore formed by the piston 15 and a pressure equalization line section 41, and this connection can be interrupted by the relative movement of the piston 17 (during operation) in the housing. A parallel connection of throttle valves with non-return valves 27 closing towards the pressure medium reservoir 4 is arranged in the pressure equalization line section 41. This means that the pressure chamber 17 is connected to the pressure medium reservoir 4, preferably to a second chamber / return chamber 4b of the pressure medium reservoir, via one or more breather holes in the non-operating state of the piston 15. This connection between the pressure chamber 17 and the pressure medium reservoir 4 is interrupted when the piston 15 operates (sufficiently) in the operating direction.

[0111] The pressure chamber 17 houses a return spring 9 which positions the piston 15 in the starting position when the master brake cylinder 2 is not operating. The piston rod 24 couples the pivotal movement of the brake pedal 51 resulting from pedal actuation to the translational movement of the (master brake cylinder) piston 15, and its actuation stroke is preferably detected by a movement sensor 25 with a redundant design. In this way, a corresponding piston movement signal is an indicator of the brake pedal actuation angle. It represents the driver's braking desire.

[0112] The pressure chamber 17 is connected to the isolation valve 23 by a hydraulic line 22. The hydraulic connection between the pressure chamber 17 and the brake circuit supply line 13 can be interrupted by the isolation valve 23. A pressure sensor 20 connected to the line section 22 detects the pressure increase in the pressure chamber 17 due to the displacement of the piston 15. This pressure also represents the measurement of the driver's braking desire.

[0113] The simulation device 3 is hydraulically coupled to the master brake cylinder 2. The simulation device 3 essentially consists of a simulator chamber 29, a simulator rear chamber 30, and a simulator piston 31 that separates two chambers 29, 30 from each other. The simulator piston 31 is supported on a housing (valve block) by an elastic element 33 (for example, a simulator spring) arranged in the simulator rear chamber 30. The simulator chamber 29 can be connected to the pressure chamber 17 of the master brake cylinder 2, for example, by an electrically actuatable simulator enable valve 32.

[0114] As an example, the pressure source 5 is exclusively activated by the second electronic control and adjustment unit 12, but this is because the redundancy of the activation of the pressure source 5 is not absolutely necessary for the master brake cylinder 2 / hydraulic fallback level.

[0115] The simulator enable valve 32 is assigned to the second electrical compartment B and is activated by the second electronic control and adjustment unit 12.

[0116] The pressure sensor 20 and the movement sensor 25 are also assigned to the second electrical compartment B. The signals from the sensors are supplied to the second electronic control and adjustment unit 12 and are evaluated and processed by the second electronic control and adjustment unit 12.

[0117] The remaining components of the brake control device 100' have already been described in connection with FIG. 1 (brake control device 100).

[0118] Figure 4 schematically shows a second exemplary embodiment of a brake system according to the present invention. Figure 4 shows the system architecture of the brake system. The exemplary brake system comprises two hydraulically actuable wheel brakes 8a, 8b and two electromechanically actuable wheel brakes 80a, 80b, and an electrohydraulic brake control device 100' according to Figure 3. Otherwise, the system architecture of the second exemplary embodiment corresponds to the system architecture of the first exemplary embodiment of Figure 2, except that there is a difference that the actuating device 300 (and its signal / data connection) is not provided, which is because the brake control device 100' comprises a master brake cylinder 2 having a brake pedal 51.

[0119] A common feature of the exemplary embodiments is that the hydraulic wheel brakes 8a, 8b are in each case connected to the brake control device 100 (100') via two wheel lines 81a, 81b and 82a, 82b.

[0120] The first wheel lines 81a, 81b are used to increase the pressure, which is provided by an electrically actuated pressure source 5 (by pushing the piston 36 forward) via open inlet valves 6a, 6b (with closed outlet valves 7a, 7b). In this case, the activation valve 26 is open and the isolation valve 23 is closed.

[0121] The pressure release for releasing all of the wheel brakes 8a, 8b (for example, for normal brakes without antilock brake control) is usually effected by pulling the piston 36 back in the reverse direction, i.e., by sucking the pressure medium of the electrically actuated pressure source 5 into the pressure chamber 37 by pulling back the piston 36 via the first wheel lines 81a, 81b, the open inlet valves 6a, 6b, and the open activation valve 26 (the isolation valve 23 is closed).

[0122] That is, in an anti-lock braking control system having a pressure setting specific to the wheel, (wheel) pressure release is achieved by closing the corresponding inlet valve and opening the corresponding outlet valve. Thereby, the pressure is released to the pressure medium reservoir 4 via the second wheel lines 82a, 82b.

[0123] This results in an (overall) annular flow, that is, the pressure medium is sent from the pressure medium reservoir 4 to the pressure source 5 (during replenishment), sent to the wheel brakes 8a, 8b via the inlet valves 6a, 6b and the first wheel lines 81a, 81b, and returned to the pressure medium reservoir 4 via the second wheel lines 82a, 82b and the outlet valves 7a, 7b. This annular flow is suitable for periodically purging the brake control device or the brake system. The existing air bubbles are removed and discharged in the pressure medium reservoir 4.

[0124] This is preferably used for a method for initial filling / self-filling of the brake system. The brake control devices 100, 100' are provided in a pre-filled state with a pressure medium (brake fluid) prepared and held in the pressure medium reservoir 4 and installed in the vehicle. The wheel lines 81a, 81b, 82a, 82b and the brake calipers of the wheel brakes 8a, 8b are installed in a dry state, that is, without filling. After all connections and the supply of electrical energy are provided, the brake control devices 100, 100' can fill the previously dry wheel lines 81a, 81b, 82a, 82b and the wheel brakes 8a, 8b via the annular flow described above.

[0125] Subsequently, the success of the filling can be confirmed by the angle / position sensor 44 and the pressure sensor 19 of the pressure source 5, and if necessary, an error message can be output if a leak is detected.

[0126] The brake calipers of the wheel brakes 8a, 8b, and their connections to the wheel lines, and the installation positions of the connections (pressure increase wheel connections 61a, 61b and pressure release wheel connection 62a (62b)) must be designed such that the pressure medium (pressure increase wheel connections 61a, 61b) is supplied in a geometrically lower area, and the pressure medium (pressure release wheel connections 62a, 62b) is discharged via a geometrically higher area so that no air pockets remain in the brake caliper. There is no need to install a vent screw on the brake caliper.

[0127] Preferably, especially for self-filling, the following method steps are carried out. Purge a wheel brake such as the wheel brake 8b (FR) (first purge cycle). a) Open the start valve 26, close the separation valve 23, and open the outlet valve 7b assigned to the wheel brake. b) Actuate the piston 36 of the pressure source 5 (in the forward direction / the operating direction of the brake). Thus, the pressure medium volume is pushed in the direction of the pressure medium reservoir 4 through the open inlet valve 6b, the first wheel line 81b, the wheel brake (brake caliper) 8b, the second wheel line 82b, and the open outlet valve 7b. c) When the piston 36 of the pressure source 5 reaches the front end (the right end in FIGS. 1 and 3) (which can be monitored by an angle sensor 44 or a displacement sensor around the piston 36), the start valve 26 is closed and the piston 36 of the pressure source 5 retracts (i.e., in the opposite direction to the operating direction of the brake), so that the pressure medium is replenished from the pressure medium reservoir 4 to the pressure chamber 37. d) Repeat steps a) to c) several times as necessary.

[0128] Purge another wheel brake such as the wheel brake 8a (FL) (second purge cycle). a) Open the start valve 26, close the separation valve 23, and open the outlet valve 7a assigned to the wheel brake. b) Actuate the piston 36 of the pressure source 5 (in the forward direction / the operating direction of the brake). Therefore, the pressure medium volume is pushed in the direction of the pressure medium reservoir 4 through the open inlet valve 6a, the first wheel line 81a, the wheel brake (brake caliper) 8a, the second wheel line 82a, and the open outlet valve 7a. c) When the piston 36 of the pressure source 5 reaches the front end (the right end in FIGS. 1 and 3) (which can be monitored by an angle sensor 44 or a displacement sensor around the piston 36), the start valve 26 is closed, and the piston 36 of the pressure source 5 retracts (in the direction opposite to the operating direction of the brake), so that the pressure medium is replenished from the pressure medium reservoir 4 into the pressure chamber 37. d) If necessary, repeat steps a) to c) several times.

[0129] Preferably, the following method steps for leak testing are performed. a) Close the isolation valve 23, open the start valve 26, and leave all other valves (6a, 6b, 7a, 7b, and 32 if necessary) blocked (i.e., the inlet valve is open and the outlet valve is closed). b) Build a test pressure of, for example, 100 bar by the pressure source 5. In particular, the displacement pressure medium volume required to reach the test pressure is determined. c) Wait for a (short) stabilization time. d) Start the measurement phase. At least one of the following variables is monitored by one of the sensors of the brake control device. Change in pressure medium volume (e.g., by the angle / position sensor 44 of the pressure source 5), pressure drop (e.g., by the pressure sensor 19). There should be no change in the pressure medium volume during the specified measurement time. Alternatively, the pressure drop should not occur with the retained pressure medium volume or is compared with a specified test value / comparison value. The displacement pressure medium volume required to reach the test pressure is compared with a specified value. e) End the leak test.

[0130] The self - filling method is completed by enabling the brake system.

[0131] In addition to self - filling, the brake control device according to the invention, or the brake system according to the invention, enables further methods for operation, which restore or improve the function of the brake control device or the brake system (for example, active pressure medium cooling, self - venting).

[0132] When descending a mountain pass (for example, when descending from the Grossglockner mountain pass), the wheel brakes are subject to high thermal loads. If there is a suspicion of overheating of the pressure medium (brake fluid), advantageously, a corresponding purge process / purge cycle as in the case of self - filling is carried out for the active cooling of the pressure medium. If the driver is not currently applying the brakes, the same purge process / purge cycle (steps a) - c)) is preferably carried out for pressure medium cooling. If the driver is continuously applying the brakes, the purge process / purge cycle is incorporated into the braking process. For example, the pressure medium circular flow can be superimposed on normal braking, similar to anti - lock brake control.

[0133] The following method steps are preferably carried out, in particular, in operating situations that thermally load the wheel brakes (active pressure medium cooling). The thermal load is optionally monitored and detected by the brake temperature model or also by existing sensors, for example, force sensors with temperature output arranged in electro - mechanical wheel brakes.

[0134] If there is a suspicion of overheating of the pressure medium, a purge cycle is executed. Alternatively, both wheel brakes can be subjected to a purge process / purge cycle, either simultaneously or sequentially. In this case, the heated pressure medium is directed away from one or more hydraulically actuated wheel brakes 8a, 8b (see purge cycle steps a), b)) towards the pressure medium reservoir 4 (from the brake caliper) via the second wheel lines 82a, 82b). Fresh cold pressure medium flows in from the pressure medium reservoir 4 (see purge cycle step c)). Thereby, the formation of vapor bubbles can be avoided or prevented.

[0135] To improve the effect, it is advantageous to provide second wheel lines 82a, 82b having an enlarged surface (for example, by cooling fins) or to form a heat sink.

[0136] If the purge process / purge cycle is executed during brake actuation, the brake torque of the electromechanically actuated wheel brakes 80a, 80b (for example, of the rear axle) is increased by the amount of the brake torque deficiency of the hydraulically actuated wheel brakes 8a, 8b (for example, of the front axle) during the purge cycle for compensation. This means that the driver does not notice a change in deceleration.

[0137] Alternatively, the purge process / purge cycle can be executed in a tactilely recognizable manner such that the driver receives feedback about a critical situation. For example, the insufficient brake torque of the hydraulically actuated wheel brakes during the purge cycle is not compensated by increasing the brake torque with the electromechanically actuated wheel brakes 80a, 80b.

[0138] The above method of active pressure medium cooling has the advantage that it can omit or delay brake fluid replacement, or the wheel brakes 8a, 8b can be designed with less thermal margin, thus avoiding costs.

[0139] The above purge cycle is also a vent cycle (self-vent) that can be executed by the brake system / brake control device periodically (e.g., according to a predetermined time schedule) and / or in a certain state (e.g., after a regular plurality of volume captures).

[0140] For example, in the switched-off state, when steam bubbles are formed after a previous heat load (so-called heat sink), after the start of the brake system, venting at the workplace can be avoided because the brake system / brake control device automatically vents by executing a purge cycle.

[0141] Brake fluid replacement at the workplace is also simplified by the brake control device according to the invention or the brake system according to the invention. During the purge cycle, only the old brake fluid (old pressure medium) is removed from the second chamber / return chamber 4b of the pressure medium reservoir 4, and the new brake fluid (new pressure medium) must be filled into the first chamber / LAC chamber 4a of the pressure medium reservoir 4. Advantageously, the replacement cycle is carried out via a liquid level warning device.

[0142] The brake control devices 100, 100' according to the invention provide the advantage that they can be provided to vehicle manufacturers in a pre-filled state for installing in a vehicle a brake control device having unfilled wheel lines (81, 82) and wheel brake calipers (wheel brakes 8a, 8b). After the installation and start of the brake system, the brake system or the brake control device executes a self-filling process.

Claims

Claim 1 An electrohydraulic brake control device (100, 100') for a hydraulically actuable wheel brake (8a, 8b), comprising an electrically actuable hydraulic source (5), an inlet valve (6a, 6b) for each of the hydraulically actuable wheel brakes (8a, 8b), an outlet valve (7a, 7b) for each of the hydraulically actuable wheel brakes (8a, 8b), and a pressure medium reservoir (4). In the electrohydraulic brake control device (100, 100'), For at least one of the hydraulically actuable wheel brakes (8a, 8b), the brake control device (100, 100') is characterized by having a pressure increase wheel connection (61a, 61b) and a pressure release wheel connection (62a, 62b). Claim 2 For at least one of the hydraulically actuable wheel brakes (8a, 8b), the pressure increase wheel connection (61a, 61b) is connected to the electrically actuable hydraulic source (5) via the inlet valve (6a, 6b) assigned to the hydraulically actuable wheel brake (8a, 8b), and the pressure release wheel connection (62a, 62b) is connected to the pressure medium reservoir (4) via the outlet valve (7a, 7b) assigned to the hydraulically actuable wheel brake (8a, 8b). The electrohydraulic brake control device (100, 100') according to claim 1 is characterized by this. Claim 3 The brake control devices (100, 100') for each of the hydraulically actuable wheel brakes (8a, 8b) are characterized by having a pressure increase wheel connection (61a, 61b) and a pressure release wheel connection (62a, 62b), and for each of the hydraulically actuable wheel brakes (8a, 8b), the pressure increase wheel connection (61a, 61b) is connected to the electrically actuable hydraulic source (5) via the inlet valves (6a, 6b) assigned to the respective hydraulically actuable wheel brakes (8a, 8b), and the pressure release wheel connection (62a, 62b) is connected to the pressure medium reservoir (4) via the outlet valves (7a, 7b) assigned to the respective hydraulically actuable wheel brakes (8a, 8b). The electro-hydraulic brake control device (100, 100') according to claim 1 or 2.

4. The electro-hydraulic brake control device (100, 100') according to any one of claims 1 to 3, characterized in that the electrically actuable hydraulic source (5) is formed by a cylinder-piston device having a pressure chamber (37) and a piston (36), and the piston (36) can be pushed back and forth by an electromechanical actuator (35, 39).

5. The electro-hydraulic brake control device (100, 100') according to any one of claims 1 to 4, characterized in that the electrically actuable hydraulic source (5) is connected to a brake line section (13) to which the inlet valves (6a, 6b) are connected via an electrically actuable start valve (26).

6. The electro-hydraulic brake control device (100, 100') according to claim 5, characterized in that the brake line section (13) can be connected to the pressure medium reservoir (4) via an electrically actuable isolation valve (23).

7. The pressure medium reservoir (4) is characterized by having a first reservoir chamber (4a) and a second reservoir chamber (4b) separated from each other by a partition wall, and the electrically activatable hydraulic source (5) is connected to the first reservoir chamber (4a) of the pressure medium reservoir (4) via a replenishment line (42) by a check valve (53) that opens in the direction of the pressure source, and one or more of the pressure release wheel connections (62a, 62b) are connected to the second reservoir chamber (4b). The electro-hydraulic brake control device (100, 100') according to any one of claims 1 to 6.

8. A brake system for an automobile, comprising at least two hydraulically actuable wheel brakes (8a, 8b), an electrically activatable hydraulic source (5), inlet valves (6a, 6b) for each hydraulically actuable wheel brake (8a, 8b), outlet valves (7a, 7b) for each hydraulically actuable wheel brake (8a, 8b), and a pressure medium reservoir, and an electro-hydraulic brake control device (100, 100'). In the brake system, for each hydraulically actuable wheel brake (8a, 8b), the brake control device (100, 100') is connected to the hydraulically actuable wheel brake (8a, 8b) via first and second hydraulic connection elements (81a, 82a, 81b, 82b).

9. The brake control device (100, 100') for each of the hydraulically actuable wheel brakes (8a, 8b) has a pressure increase wheel connection (61a, 61b) and a pressure release wheel connection (62a, 62b). The brake system according to claim 8.

10. For each hydraulically actuatable wheel brake (8a, 8b), the first hydraulic connection element (81a, 81b) connects the inlet valve (6a, 6b) assigned to the hydraulically actuatable wheel brake (8a, 8b) to the pressure port (801a, 801b) of the hydraulically actuatable wheel brake (8a, 8b), and for each hydraulically actuatable wheel brake (8a, 8b), the second hydraulic connection element (82a, 82b) connects the outlet valve (7a, 7b) assigned to the hydraulically actuatable wheel brake (8a, 8b) to the drain port (802a, 802b) of the hydraulically actuatable wheel brake (8a, 8b). The brake system according to claim 8 or 9 is characterized by this.

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

12. A brake system according to any one of claims 8 to 11, having at least one wheel brake (80a, 80b) actuatable by an electromechanical actuator, in particular having two wheel brakes (80a, 80b) each actuatable by an electromechanical actuator.

13. Characterized by comprising two wheel brakes (80a, 80b) each actuatable by an electromechanical actuator, wherein one (80a) of the wheel brakes actuatable by the electromechanical actuator is supplied with electrical energy by a first electrical energy source (PWR1), and the other wheel brake (80b) actuatable by the electromechanical actuator is supplied by a second electrical energy source (PWR2) independent of the first electrical energy source (PWR1). The brake system according to claim 12.

14. A method for operating the brake system according to any one of claims 8 to 13, wherein the brake control device (100, 100') is used to execute a purge cycle. c) In particular, by actuating the electrically actuable hydraulic source (5) in the actuation direction of the brake, the pressure medium moves through the first inlet valve of the inlet valves (6a, 6b), through the first hydraulically actuable wheel brake (8a, 8b) assigned to the first inlet valve, and through the 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, thereafter, d) In particular, by actuating the electrically actuable hydraulic source (5) in the direction opposite to the actuation direction of the brake, the pressure medium is sucked from the pressure medium reservoir (4) into the electrically actuable hydraulic source (5), In particular, steps a) and b) are repeatedly carried out periodically A method, characterized in that.

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

16. Subsequently, a leak test of the brake system is carried out by the brake control device (100, 100'), and the test pressure is increased and maintained by the electrically actuable hydraulic source (5), characterized in that The method according to claim 15.

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

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

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

20. The method according to any one of claims 14 to 18, characterized in that, in particular, this method for cooling the pressure medium is carried out when a heat load of the brake system or of one of the wheel brakes (8a, 8b, 80a, 80b) has been detected on the basis of a monitoring method.

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

22. The method according to any one of claims 14 to 18, characterized in that, in particular, this method for venting the brake control device (100, 100') is repeated and / or carried out in a predetermined state.

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