CONTROL DEVICE, ESP HYDRAULIC UNIT COMPRISING SUCH CONTROL DEVICE, SYSTEM COMPRISING SUCH ESP HYDRAULIC UNIT, AND METHOD FOR OPERATING SUCH SYSTEM

Abstract

The invention relates to a control device (50) for a brake system of a vehicle equipped with a brake actuation hydraulic unit (30) and an ESP hydraulic unit (32) and to a method for operating a brake system of a vehicle equipped with a brake actuation hydraulic unit (30) and an ESP hydraulic unit (32), in which the occurrence of at least one predefined error state in the brake actuation hydraulic unit (30) associated with the ESP hydraulic unit (32) is read or checked with reference to at least one signal (52) and, taking into account the at least one signal (52), a brake actuation control device (50) for a brake actuation hydraulic unit (30) and an ESP hydraulic unit (32) for a brake actuation hydraulic unit (30) are activated. When it is determined that at least one predetermined error condition has occurred in the ESP hydraulic unit (30), at least one of the following steps is executed: at least one pump (40) of the ESP hydraulic unit (32) is activated to draw a fixedly set or determined brake fluid volume from a brake fluid reservoir (54) of the brake system, and / or at least one electric motor (48) of the vehicle operable in a regenerative mode is activated to generate a fixedly set or determined motor brake torque (Bmotor) not equal to zero on at least one wheel of the vehicle and / or on at least one axle of the vehicle.

Description

[Technical field]

[0001] The invention relates to a control device for a braking system of a vehicle equipped with a brake actuation hydraulic unit and an ESP hydraulic unit. The invention likewise relates to an ESP hydraulic unit for a braking system of a vehicle additionally equipped with a brake actuation hydraulic unit and to a braking system for a vehicle. Furthermore, the invention relates to a method for operating a braking system of a vehicle equipped with a brake actuation hydraulic unit and an ESP hydraulic unit. [Background technology]

[0002] FIG. 1 illustrates a conventional braking system known to applicant as internal prior art.

[0003] The conventional braking system shown diagrammatically in Fig. 1 comprises a hydraulic system 10 in which a master brake cylinder 12 and an ESP system 14 are integrated. For each wheel 16 of a vehicle equipped with a conventional braking system, one wheel brake cylinder 18 is connected to the hydraulic system 10. Furthermore, a brake fluid reservoir 20, an electromechanical brake booster 22 and a brake pedal 24 are connected to the master brake cylinder 12. The electromechanical brake booster 22 can be used in particular as an actuator / regulator for initiating a driver-assisted or autonomous brake pressure build-up in the wheel brake cylinders 18. By an ESP system 14 operable by a control device 26, it is understood that component of the conventional braking system is designed to perform ABS and / or ESP functions. Summary of the Invention

[0004] The present invention provides a control device for a brake system of a vehicle equipped with a brake actuation hydraulic unit and an ESP hydraulic unit, having the features of claim 1, an ESP hydraulic unit for a brake system of a vehicle additionally equipped with a brake actuation hydraulic unit, having the features of claim 6, a brake system for a vehicle, having the features of claim 8, and a method for operating a brake system of a vehicle equipped with a brake actuation hydraulic unit and an ESP hydraulic unit, having the features of claim 12.

[0005] The invention creates the possibility of improved utilization of a braking system equipped with an ESP hydraulic unit and a brake actuation hydraulic unit, thus simplifying its implementation. As will become clear with reference to the following description, the invention allows the advantages of a braking system equipped with an ESP hydraulic unit and a brake actuation hydraulic unit, in particular with respect to a conventional braking system having only a single hydraulic unit. The invention embodies in particular the use of the ESP hydraulic unit and / or at least one electric motor of the vehicle equipped with the respective braking system for carrying out autonomous braking and for providing a forceful assistance to the driver of the vehicle under driver-initiated braking in the event of a malfunction or failure of the brake actuation hydraulic unit. Accordingly, in such situations where a conventional braking system often only has its mechanical fallback level available for braking the vehicle, the invention nevertheless allows a good braking comfort for the driver to be generated.

[0006] If the control device, taking into account the at least one signal, determines that only one predefined error state or at least one of a number of predefined error states has occurred in the brake actuation hydraulic unit, the control device, taking into account at least one sensor signal of at least one brake actuation member sensor of the brake system and / or of at least one pressure sensor of the ESP hydraulic unit and / or the brake actuation hydraulic unit, is preferably designed and / or programmed to determine a target volume of brake fluid to be sucked from the brake fluid reservoir and subsequently activate at least one pump of the ESP hydraulic unit to suck from the brake fluid reservoir a brake fluid volume corresponding to the determined target volume. In this way, the braking caused in this way can be adapted to the current braking demand.

[0007] Alternatively or additionally, if the control device determines, after considering the at least one signal, that only one predefined error state or at least one of a number of predefined error states has occurred in the brake actuation hydraulic unit, the control device may be designed and / or programmed to determine, after considering at least one sensor signal of at least one brake actuation member sensor of the brake system and / or of at least one pressure sensor of the ESP hydraulic unit and / or the brake actuation hydraulic unit, a target brake torque of the motor brake torque to be applied to at least one wheel and / or at least one axle and subsequently activate the at least one electric motor to induce a motor brake torque corresponding to the determined target brake torque for at least one wheel and / or at least one axle. The induced operation of the at least one electric motor can thus also be adapted to the current brake request.

[0008] In one preferred embodiment, the control device is designed and / or programmed to recognize a malfunction and / or failure of a brake booster of the brake actuation hydraulic unit, a malfunction and / or failure of at least one valve of the brake actuation hydraulic unit, a malfunction and / or failure of at least one sensor device of the brake actuation hydraulic unit, and / or a malfunction and / or failure of a first current supply of at least the brake booster of the brake actuation hydraulic unit, of at least one valve of the brake actuation hydraulic unit and / or of at least one sensor device of the brake actuation hydraulic unit as at least one predefined error state with reference to the at least one signal. Thus, the control device embodiments described herein can activate / operate the ESP hydraulic unit and / or at least one regeneratively operable electric motor under multiple error conditions of the brake actuation hydraulic unit for force assistance of the driver-initiated braking and / or for performing / continuing autonomous braking. Thus, error conditions where only a mechanical fallback level is conventionally available can be preferably bridged at least temporarily by the control device embodiments described herein.

[0009] The control device is preferably designed and / or programmed to recognize a wheel lock caused by at least one of the wheel brake cylinders with reference to at least one measurement signal of at least one speed sensor of at least one wheel of the vehicle, if at least one predefined error state does not occur in the brake actuation hydraulic unit, and to possibly switch at least one valve of the ESP hydraulic unit to an open state so that brake fluid can be released from the at least one locked wheel brake cylinder via the at least one valve that has been switched to an open state. Thus, in addition to the preferred properties described above, the embodiments of the control device described here can also trigger the removal of the wheel lock.

[0010] An ESP hydraulic unit for a vehicle's braking system which is additionally equipped with at least a brake actuation hydraulic unit and which has such a control device also embodies the advantages explained above.

[0011] For example, the ESP hydraulic unit may include at least one high-pressure switching valve, via which the suction side of each of the at least one pump of the ESP hydraulic unit is hydraulically connectable or connected to a brake fluid reservoir of the brake system, and the control device is additionally designed and / or programmed to switch the at least one high-pressure switching valve to an open state during activated operation of the at least one pump in order to suck in a brake fluid volume from the brake fluid reservoir, which embodies a rapid transfer of the brake fluid volume from the brake fluid reservoir, in particular to the ESP hydraulic unit.

[0012] The advantages described above are also realized in a braking system for a vehicle having a corresponding ESP hydraulic unit, a brake actuation hydraulic unit mounted to the ESP hydraulic unit, and wheel brake cylinders mounted to the ESP hydraulic unit.

[0013] In one preferred embodiment of the brake system, the brake actuation hydraulic unit is connectable or connected to a first current supply and the ESP hydraulic unit is connectable or connected to a second current supply, such that the ESP hydraulic unit can still be utilized to perform / continue autonomous braking and / or to dynamically assist braking induced by the driver even in the event of failure of the first current supply, which would clearly limit the functionality of the brake actuation hydraulic unit.

[0014] The brake actuation hydraulic unit preferably includes control electronics designed and / or programmed to at least activate a brake booster of the brake actuation hydraulic unit, taking into account at least a brake operating member sensor of the brake system and / or at least one pressure sensor of the brake actuation hydraulic unit, such that the control electronics can be utilized to offload a preferred controller of the brake system during normal operation of the brake system when no error condition exists in the brake actuation hydraulic unit.

[0015] In another preferred embodiment of the brake system, the brake booster of the brake actuation hydraulic unit is a brake booster upstream of the master brake cylinder of the brake actuation hydraulic unit or a motorized piston-cylinder device integrated into the hydraulic system of the brake actuation hydraulic unit. In both of these cases, the brake booster can be utilized during normal operation of the brake system equipped with it, without any fault condition in the brake actuation hydraulic unit, to perform autonomous braking and / or to dynamically assist braking induced by the driver, and can be preferably bridged at least temporarily by the ESP hydraulic unit during the absence of availability of the brake booster for this purpose.

[0016] Furthermore, the implementation of a corresponding method for actuating a brake system of a vehicle equipped with a brake actuation hydraulic unit and an ESP hydraulic unit also produces the above-described advantages, which method can be explicitly pointed out as being developmental on the basis of the above-described embodiments of the control device, the ESP hydraulic unit and / or the brake system.

[0017] Further features and advantages of the present invention will be described with reference to the following drawings, in which: [Brief description of the drawings]

[0018] [Figure 1] This is a conventional braking system. [Diagram 2] 1 is a schematic diagram showing a brake system equipped with a brake actuation hydraulic unit and an ESP hydraulic unit to explain an embodiment of the control device. FIG. [Figure 3a]1 is a flow chart illustrating an embodiment of a method for actuating a brake system of a vehicle equipped with a brake actuation hydraulic unit and an ESP hydraulic unit. [Figure 3b] 1 is a coordinate system for illustrating an embodiment of a method for actuating a brake system of a vehicle equipped with a brake actuation hydraulic unit and an ESP hydraulic unit. [Figure 3c] 1 is a coordinate system for illustrating an embodiment of a method for actuating a brake system of a vehicle equipped with a brake actuation hydraulic unit and an ESP hydraulic unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] FIG. 2 shows a schematic diagram of a brake system equipped with a brake actuation hydraulic unit and an ESP hydraulic unit to explain an embodiment of the control device.

[0020] The brake system, which is shown diagrammatically in FIG. 2, comprises a brake actuation hydraulic unit 30 and an ESP hydraulic unit 32. The brake actuation hydraulic unit 30 means a unit produced separately from the ESP hydraulic unit 32, which can also be called a brake actuation hydraulic module 30 or brake actuation hydraulic subassembly 30. The brake actuation hydraulic unit 30 comprises at least one master brake cylinder 34 and a brake booster 36, the brake actuation hydraulic unit 30 being connected / connected or assembled / assembled only after the ESP hydraulic unit 32 has been produced. As will become clear with reference to the following description, it is an option for the brake system to be equipped with a brake operating member 38, for example a brake pedal 38, connected to the master brake cylinder 34, due to the high safety level of the brake system in carrying out autonomous braking.

[0021] The ESP hydraulic unit 32, which may also be referred to as the ESP hydraulic module 32 or ESP hydraulic subassembly 32, is understood to be a unit manufactured separately from the brake actuation hydraulic unit 30. The ESP hydraulic unit 32 integrates hydraulic components, in particular at least one pump 40, by means of which ABS and / or ESP functions can be performed in the brake system of FIG.

[0022] In addition to the brake actuation hydraulic unit 30 and the ESP hydraulic unit 32, the braking system further comprises wheel brake cylinders 42 connected / assembled to the ESP hydraulic unit 32. The total number of wheel brake cylinders 42 of the braking system may correspond to the total number of wheels of the vehicle on which it should / is equipped. It should be pointed out that the applicability of the braking system is not limited to a specific vehicle model / automobile type of vehicle / automobile equipped with the braking system, nor to a specific total number of wheels of the vehicle / automobile.

[0023] The brake system of Fig. 2 has two brake circuits 44a and 44b by way of example only. Furthermore, the hydraulic units 30 and 32 are connected to each other by way of example only, one brake pipe 46 for each brake circuit 44a and 44b. The hydraulic connections of both hydraulic units 30 and 32 shown diagrammatically in Fig. 2 should be interpreted as being merely exemplary.

[0024] 2 also illustrates a controller 50 that is designed and / or programmed to determine whether at least one predetermined error condition has occurred in the brake actuation hydraulic unit 30. The determination of the at least one predetermined error condition that may have occurred in the brake actuation hydraulic unit 30 is made by inspecting or reading at least one signal 52 provided to the controller 50 (examples of at least one signal 52 that may be read and / or inspected by the controller 50 are provided below).

[0025] Possibly, i.e. when the control device 50 determines, after taking into account the at least one signal 52, that only one predefined error state or at least one of a number of predefined error states has occurred in the brake actuation hydraulic unit 30, the control device 50 is designed and / or programmed to execute at least one of two measures, which will be described later. For example, as a first measure, the control device 50 may be designed and / or programmed to at least activate, by means of at least one first control signal 40s, the at least one pump 40 of the ESP hydraulic unit 32 in order to suck a brake fluid volume, which is fixedly set or determined by the control device 50, from a brake fluid reservoir 54 of the brake system. The brake fluid reservoir 54 from which the brake fluid volume additionally sucked into the brake circuits 44a and 44b is taken is preferably a brake fluid reservoir 54, in particular connected to the master brake cylinder 34 via at least one orifice hole.

[0026] An additional brake fluid volume is sucked in from the brake fluid reservoir 54 (strategy 1), so that the wheel brake cylinders 42 are additionally filled. Measure 1 therefore allows a forceful assistance of driver-initiated braking, despite a malfunction or failure of the brake actuation hydraulic unit 30. Driver-initiated braking is understood to mean braking requested by the driver by means of a driver braking force (not equal to zero) exerted on the brake operating member 38. However, with measure 1 it is also possible to carry out or continue an autonomous braking of the vehicle. In the following, autonomous braking is understood to mean braking requested by an automatic speed control system of the vehicle, without the driver operating the brake operating member 38. The automatic speed control system can be, for example, a distance cruise control or an emergency braking system.

[0027] It should be noted here that the means embodied by the controller 50 for drawing additional brake fluid volume from the brake fluid reservoir 54 on demand often permits reduced sizing of the master brake cylinder 34. Accordingly, the preferred configuration / programming of the controller 50 facilitates compaction of the brake system of FIG.

[0028] Alternatively or additionally, the control device 50 may be designed and / or programmed as a second measure to operate at least one electric motor 48 of a vehicle equipped with a brake system by at least one second control signal 48s to generate a motor braking torque not equal to zero, fixedly set or determined by the control device 50, on at least one wheel of the vehicle and / or on at least one axle of the vehicle. At least one electric motor 48 is understood to be a motor which, when in regenerative mode, is capable of decelerating / is operable to decelerate the vehicle by a motor braking torque generated on at least one wheel and / or at least one axle. The at least one electric motor 48 may in particular be a drive motor of the vehicle operable in regenerative mode.

[0029] Measure 2 thereby enables the shared use of the at least one electric motor 48 for decelerating the vehicle even in the event of a malfunction or failure of the brake actuation hydraulic unit 30. By operating the at least one electric motor 48 according to measure 2, the driver can receive a forceful assistance during driver-induced braking, since in addition to the friction braking torque exerted by the wheel brake cylinders 42 the vehicle is further decelerated by a motor braking torque of the at least one electric motor 48. Furthermore, according to measure 2 the at least one electric motor 48 can also be utilized to continue or perform autonomous braking by a motor braking torque exerted on at least one wheel and / or at least one axle of the vehicle, even in the event of a malfunction or failure of the brake actuation hydraulic unit 30.

[0030] The preferred design / programming of the control device 50 accordingly embodies preferred means for providing a forceful assistance of the driver-initiated braking or for carrying out autonomous braking even in the event of a malfunction or failure of the brake actuation hydraulic unit 30. The preferred design / programming of the control device 50 thus brings about an extension of conventional emergency functions, in particular for providing a forceful assistance of the driver-initiated braking and / or for continuing or carrying out autonomous braking even in the event of a total failure of the brake booster 36 normally used for this purpose. Whereas in a conventional braking system, in the event of a total failure of the brake booster, a forceful assistance of the driver-initiated braking is usually not possible and autonomous braking must be immediately discontinued, this drawback is eliminated by the use of the control device 50 for the brake system type described here. It should be pointed out that even in the event of an obvious malfunction of the brake actuation hydraulic unit 30, the brake system of FIG. 2 still does not operate at a mechanical fallback level. This is because the above-described measures can still be applied by the control device 50 and the ESP hydraulic unit 32 for force assistance of braking induced by the driver and / or for the continuation or execution of autonomous braking.

[0031] 2 equipped with the control device 50 thus has a preferably high safety level, in particular for the performance of autonomous braking, so that it is also possible to omit equipping the brake system with the brake operating member 38.

[0032] If the control device 50 determines, after taking into account the at least one signal 52, that only one predefined error condition or one of a number of predefined error conditions occurs in the brake actuation hydraulic unit 30, the control device 50 is preferably designed and / or programmed to determine a target volume of brake fluid volume to be sucked from the brake fluid reservoir 54. The target volume can be determined based on a braking desire expressed by the driver by operating the brake actuation member 38, with the target volume being determined after taking into account at least one sensor signal 56 of at least one brake actuation member sensor 58 of the brake system and / or of at least one pressure sensor 60, 62 of the ESP hydraulic unit 30 and / or the brake actuation hydraulic unit 32. The control device 50 can then activate / operate the at least one pump 40 of the ESP hydraulic unit 32 to suck from the brake fluid reservoir 54 a brake fluid volume corresponding to the determined target volume. Due to the at least one sensor signal 56 being taken into account when determining the desired volume during braking initiated by the driver, the generated force assistance is a metered increase in the braking initiated by the driver based on the driver's braking intent. Accordingly, due to the at least one sensor signal 56 being taken into account when determining the desired volume, the braking intent of the automatic speed control system can be reliably respected during autonomous braking. Due to the described method when the brake fluid volume is sucked from the brake fluid reservoir 54, the brake pressure in the wheel brake cylinders 42 always increases in accordance with the braking intent of the driver or the automatic speed control system, so that the driver does not / only notices the temporary reaction force generated at the same time on the brake operating member 38 as being disturbing.

[0033] Likewise, if the control device 50 determines, after taking into account the at least one signal 52, that only one predefined error state or at least one of a number of predefined error states has occurred in the brake actuation hydraulic unit 30, the control device may be designed and / or programmed to determine a target brake torque for the motor brake torque to be applied to the at least one wheel and / or at least one axle. To determine the target brake torque, at least one sensor signal 56 of the at least one brake actuation member sensor 58 and / or the at least one pressure sensor 60 and 62 may also be evaluated. If necessary, the control device 50 subsequently activates the at least one electric motor 48 to generate a motor brake torque corresponding to the determined target brake torque for the at least one wheel and / or at least one axle. The method described here allows the induced motor braking torque to comply with the braking request requested by operating the brake operating member 38 or the automatic speed control system, not only in the case of forceful braking assistance induced by the driver, but also in the case of continued or executed autonomous braking, so that good braking and driving comfort remain guaranteed despite a malfunction or failure of the brake actuation hydraulic unit 30.

[0034] The at least one brake operating member sensor 58 may be, for example, a rod stroke sensor and / or a stroke difference sensor. The at least one pressure sensor 60 and 62 may be a pressure sensor 60 of the brake actuation hydraulic unit 30 connected to the master brake cylinder 34 and / or a pressure sensor 62 of the ESP hydraulic unit 32. The control device 50 is preferably designed and / or programmed, for forceful assistance of braking initiated by the driver and / or for the continuation or execution of autonomous braking, to evaluate, as a priority, at least one sensor signal 56 of the at least one brake operating member sensor 58 and / or of the pressure sensor 60 of the brake actuation hydraulic unit 30 connected to the master brake cylinder 34, and to evaluate the sensor signal 56 of the pressure sensor 62 of the ESP hydraulic unit 32 (together) only if at least one malfunction has occurred with a high probability in the at least one brake operating member sensor 58 and / or in the pressure sensor 60 of the brake actuation hydraulic unit 30 connected to the master brake cylinder 34.

[0035] The at least one predefined error state which can be recognized by the control device 50 with reference to the at least one signal 52 can be, for example, a malfunction and / or a failure of the brake booster 36 of the brake actuation hydraulic unit 30. The malfunction or failure of the brake booster 36 can be recognized with reference to an evaluation or comparison of at least one signal 52 of a pressure sensor 62 of the ESP hydraulic unit 32 and / or of a pressure sensor 64 of the brake actuation hydraulic unit 30 connected to the brake booster 36 with at least one signal 52 of at least one brake actuation member sensor 58 and / or of a pressure sensor 60 of the brake actuation hydraulic unit 30 connected to the master brake cylinder 34. For the inspection / check of the brake booster 36, it is also possible to evaluate (together) at least one signal 52 of a motor current sensor of the brake booster 36 and / or of a rotation angle sensor 66 of the brake booster 36. Malfunctions and / or failures of at least one valve of the brake actuation hydraulic unit 30 can also be recognized as a predefined error state by evaluation or comparison of at least one signal 52 of the at least one brake actuation member sensor 58, of at least one pressure sensor 60, 62 and 64 of the brake actuation hydraulic unit 30 and / or the ESP hydraulic unit 32, of the motor current sensor and / or the rotation angle sensor 66. Malfunctions and / or failures of at least one sensor device of the brake actuation hydraulic unit 30, for example of its at least one pressure sensor 60 and 64, can accordingly likewise be recognized as a predefined error state by evaluation or comparison of at least one signal 52 of the at least one brake actuation member sensor 58, of at least one pressure sensor 60, 62 and 64 of the brake actuation hydraulic unit 30 and / or the ESP hydraulic unit 32, of the motor current sensor and / or the rotation angle sensor 66.Furthermore, a malfunction or failure of the first current supply in its function can be determined as a predefined error state by reference to at least one signal 52 of a current sensor (not shown) of a first current supply to which the brake booster 36, at least one valve of the brake actuation hydraulic unit 30 and / or at least one sensor device of the brake actuation hydraulic unit 30 are at least electrically connected. In this way, a large number of different error states of the brake actuation hydraulic unit 30 can be reliably detected by sensor devices already used in the vehicle in a conventional manner.

[0036] The control device 50 may in particular be a control device 50 of the ESP hydraulic unit 32. The control device 50 is preferably designed and / or programmed to recognize and possibly eliminate a wheel lock, at least if only one predefined error state or one of a number of predefined error states does not occur in the brake actuation hydraulic unit 30. The recognition of a possible wheel lock can be performed with reference to at least one measurement signal of a speed sensor (not shown) of at least one wheel of the vehicle. In this way, it can be reliably recognized whether one of the wheels of the vehicle is locked by at least one of the wheel brake cylinders 42. When a wheel lock is recognized, at least one wheel outlet valve 68 of the ESP hydraulic unit 32 can be switched to an open state by the control device 50, so that brake fluid is discharged from the at least one locked wheel brake cylinder 42 via the at least one wheel outlet valve 68 switched to an open state. Thus, the control device 50 can also be utilized for the activation / activation of a "classic" ABS function and / or an ESP function of the ESP hydraulic unit 32. Alternatively, the control device 50 can be designed / programmed for the activation / activation of further assist or partial assist functions.

[0037] In the brake system of FIG. 2, the brake booster 36 of the brake actuation hydraulic unit 30 is, by way of example, a motorized piston-cylinder arrangement 36 integrated into the hydraulic system of the brake actuation hydraulic unit 30. The motorized piston-cylinder arrangement 36 can also be called a plunger arrangement 36 or an electric brake booster 36 decoupled from the master brake cylinder 34. The brake actuation hydraulic unit 30 equipped with the motorized piston-cylinder arrangement 36 can therefore also be called a DPB hydraulic unit 30 (Decoupled Power Brake). However, as an alternative, the brake booster 36 of the brake actuation hydraulic unit 30 can also be a brake booster, in particular an electromechanical brake booster (iBooster), arranged in front of the master brake cylinder 34 of the brake actuation hydraulic unit 30.

[0038] If only one predefined error state or one of several predefined error states does not occur in the brake actuation hydraulic unit 30, the driver's braking intervention on the wheel brake cylinders 42 can be prevented by controlling and holding the simulator isolation valve 70, through which the simulator 72 is connected to the master brake cylinder 34, in an open state. While the driver brakes the simulator 72 via the open simulator isolation valve 70 by operating the brake operating member 38, the driver-initiated braking can be selectively triggered by the motorized piston-cylinder arrangement 36, or by at least one electric motor 48 of the vehicle which can be operated in regenerative mode, or by the motorized piston-cylinder arrangement 36 and at least one electric motor 48. In all the measures for driver-initiated braking described here, the driver who brakes the simulator 72 always receives a standard brake actuation / pedal feel.

[0039] The brake actuation hydraulic unit 30 may optionally further comprise for each brake circuit 44a and 44b a first isolation valve 74, respectively, through which the associated brake circuit 44a or 44b is connected to the master brake cylinder 34, and a second isolation valve 76, respectively, through which the associated brake circuit 44a or 44b is connected to the motorized piston-cylinder device 36, which is used as the brake booster 36. Optionally, the motorized piston-cylinder device 36 may be connected to the brake fluid reservoir 54 via a further isolation valve 78 of the brake actuation hydraulic unit 30. In addition to this, at least one suction line 80 with an overpressure valve 82 may be configured in the brake actuation hydraulic unit 30, via which the brake pipe 46 is connected to the brake fluid reservoir 54. Optionally, the brake actuation hydraulic unit 30 can also have (its own) control electronics 84, which is designed and / or programmed to activate at least the brake booster 36 of the brake actuation hydraulic unit 30, taking into account at least the brake operating member sensor 58 of the brake system and / or at least one pressure sensor 60 and 64 of the brake actuation hydraulic unit 30. In this way, the control electronics 84 can take over from the controller 50. The controller 50 and the control electronics 84 are preferably designed / programmed to communicate with each other, for example via bus communication.

[0040] The ESP hydraulic unit 32 may also include at least one wheel intake valve 86 in addition to the at least one wheel outlet valve 68. Alternatively or additionally, the ESP hydraulic unit 30 may further include at least one high pressure switching valve 88 and / or at least one switching valve 90. If the suction side of each of the at least one pump 40 of the ESP hydraulic unit 32 is hydraulically connectable / connected via the at least one high pressure switching valve 88 to a brake fluid reservoir 54 of the brake system, the control device 50 may additionally be designed and / or programmed to switch the at least one high pressure switching valve 88 to an open state while the operation of the at least one pump 40 is activated in order to suck in an additional brake fluid volume from the brake fluid reservoir 54. Furthermore, at least one storage chamber 94 of the ESP hydraulic unit 32 may be connected via an overpressure valve 92 to the suction side of each of the at least one pump 40. The brake actuation hydraulic unit 30 can / is connectable to a first current supply, whereas connection to a second current supply is preferred for the ESP hydraulic unit 32. Even in case of a total failure of the first current supply, the control device 50 and the ESP hydraulic unit 32 can still perform the preferred bridging function described above in such a case.

[0041] The use of the control device 50 embodies a significantly increased degree of freedom with regard to the hydraulic design of the brake system which is equipped with it / which cooperates with it, in this way it can be ensured in particular that one particular brake system type can be used for a number of vehicle / automobile types.

[0042] 3a to 3c show a flow chart and coordinate systems for illustrating an embodiment of a method for actuating a brake system of a vehicle equipped with a brake actuation hydraulic unit and an ESP hydraulic unit.

[0043] The applicability of the method described below is not limited to a particular vehicle model / automobile type of vehicle / automobile equipped with the brake system, nor is it limited to a particular total number of wheels on the vehicle / automobile.

[0044] In method step S1, whether at least one predefined error state occurs in the brake actuation hydraulic unit is read or checked with reference to at least one signal. Examples of the at least one signal and of the at least one predefined error state have already been given above.

[0045] If it is determined with reference to the at least one signal that at least one predetermined error condition does not occur in the brake actuation hydraulic unit, the brake system operates according to a normal operating mode represented by the coordinate system of Fig. 3b, in which the horizontal axis represents time t versus the vertical axis of the coordinate system of Fig. 3b representing brake torque B.

[0046] In the normal operating mode, which is diagrammatically shown in Fig. 3b, the driver of the vehicle requests braking of the vehicle by operating a brake actuation member of the brake system. With reference to at least one sensor signal of at least one brake actuation member sensor of the brake system and / or at least one pressure sensor of the ESP hydraulic unit and / or the brake actuation hydraulic unit, the driver's braking intention is determined in method step S2. In particular, if the brake booster of the brake actuation hydraulic unit is a motorized piston-cylinder device integrated in the hydraulic system of the brake actuation hydraulic unit 30, the master brake cylinder pressure occurring in the master brake cylinder of the brake actuation hydraulic unit can be determined / estimated in order to determine the driver's braking intention.

[0047] In the embodiment of the method described herein, the motorized piston-cylinder device utilized as a brake booster has no / very little effect on the master brake cylinder pressure, which is thus (almost) exclusively caused by the driver. pMC Therefore, the brake torque B of the wheel brake cylinder of the brake system "induced only by the driver" pMC 3b, the brake torque that can be generated on the vehicle when the master brake cylinder pressure is generated in all wheel brake cylinders. However, as can be seen with reference to the coordinate system of FIG. 3b, in the normal operating mode, the brake booster is activated in method step S3, and the wheel brake cylinders of the brake system generate a significantly increased friction brake torque B friction is applied to each wheel of the vehicle. friction In particular, the brake torque B pMC and a multiplication factor greater than 1. The vehicle then operates in response to a friction brake torque B friction The total braking torque B corresponds (substantially) to total is slowed down by

[0048] The horizontal and vertical axes of the coordinate system of Fig. 3c represent time t and brake torque B. The coordinate system of Fig. 3c shows what happens if in method step S1 it is determined with reference to at least one signal that only one error state or one of a number of predefined error states has occurred in the brake actuation hydraulic unit, and possibly at least one of method steps S4 and S5 is then executed.

[0049] In that case, for example, as method step S4, at least one pump of the ESP hydraulic unit can be activated to suck in a fixedly set or determined brake fluid volume from a brake fluid reservoir of the brake system. By sucking in an additional brake fluid volume, an additional brake pressure generation is realized in each wheel brake cylinder, so that the friction brake torque B of the wheel brake cylinder is increased. friction increases.

[0050] However, in the embodiment described here, if it is recognized in method step S1 that only one error condition or one of a number of predefined error conditions occurs in the brake actuation hydraulic unit, then method step S5 is executed as method step S5, in which at least one electric motor of the vehicle capable of operating in a regenerative mode is detected to have a fixedly set or determined motor brake torque B that is not equal to zero. motor For at least one wheel of the vehicle and / or for at least one axle of the vehicle, the execution of the method step S5 thus generates a total brake torque B total is generated not only purely hydraulically, but also by at least one electric motor that is used as a generator. This leads to the volume in the master brake cylinder being sufficient for a longer period of time when high deceleration values ​​are generated. Furthermore, the execution of method step S5 is possible without negative reactions to the driver, such as, for example, noise or movement of the brake actuation element / brake pedal.

[0051] Preferably, between the recognition that only one error state or one of a number of predefined error states has occurred in the brake actuation hydraulic unit and at least one of method steps S4 and S5, a further method step S6 is performed, in which a target volume of the brake fluid volume aspirated according to method step S4 and / or a target value of the motor brake torque B to be applied to at least one wheel and / or at least one axle is determined. motor The target brake torque B of the wheel brake cylinder can be determined taking into account at least one sensor signal of at least one brake actuation element sensor of the brake system and / or at least one pressure sensor of the ESP hydraulic unit and / or the brake actuation hydraulic unit. friction and the motor brake torque B of at least one electric motor motor The total braking torque B applied as the sum of total Similarly, the brake torque B caused only by the driver pMC and a multiplication factor greater than 1.

[0052] The at least one electric motor used as a generator can be selectively used for the execution of method step S5 already when it is recognized that only one error state or one of a number of predefined error states occurs in the brake actuation hydraulic unit, and thus even at the beginning of braking. However, execution of method step S5 is preferably awaited until execution of method step S4 has made it impossible to suck hydraulic volume from the brake fluid reservoir of the brake system. In this way, linear boosting is possible without periodic checks at the driver's request. [Explanation of symbols]

[0053] 30 Brake actuation hydraulic unit 32 ESP hydraulic unit 34 Master brake cylinder 36 Brake booster 40 Pump 42 Wheel brake cylinder 48 Electric Motor 50 Control device 52 signal 54 Brake fluid reservoir 56 Sensor Signal 58 Brake operation member sensor 60,62,64 Pressure Sensors 68 Valve 84 Control Electronics 88 High pressure switching valve

Claims

1. A control device (50) for a brake system of a vehicle equipped with a brake actuation hydraulic unit (30) and an ESP hydraulic unit (32), comprising: the control device (50) is designed and / or programmed to read or check whether at least one predetermined error condition has occurred in the brake actuation hydraulic unit (30) associated with the ESP hydraulic unit (32) by reference to at least one signal (52) provided to the control device (50); If the control device (50) determines, after considering at least one of the signals (52), that only one predetermined error condition or at least one of a plurality of predetermined error conditions is occurring in the brake actuation hydraulic unit (30), the control device (50) and / or for activating at least one pump (40) of the ESP hydraulic unit (32) to draw a brake fluid volume from a brake fluid reservoir (54) of the brake system, the volume being fixedly set or determined by the control device (50). A motor brake torque (B) not equal to zero, either fixedly set or determined by the control device (50). ｍｏｔｏｒ to activate at least one electric motor (48) of the vehicle operable in a regenerative mode to generate a regenerative torque on at least one wheel and / or at least one axle of the vehicle; A control device, characterized in that it is additionally designed and / or programmed.

2. 2. The control device (50) according to claim 1, wherein if the control device (50) determines, after taking into account the at least one signal (52), that only one predefined error state or at least one of a plurality of predefined error states occurs in the brake actuation hydraulic unit (30), the control device (50) is designed and / or programmed to determine, after taking into account at least one sensor signal (56) of at least one brake operating member sensor (58) of the brake system and / or of at least one pressure sensor (60, 62) of the ESP hydraulic unit (32) and / or the brake actuation hydraulic unit (30), a target volume of brake fluid volume to be sucked from the brake fluid reservoir (54) and subsequently activate the at least one pump (40) of the ESP hydraulic unit (32) to suck from the brake fluid reservoir (54) a brake fluid volume corresponding to the determined target volume.

3. If the control device (50) determines, taking into account the at least one signal (52), that only one predefined error state or at least one of a plurality of predefined error states occurs in the brake actuation hydraulic unit (30), the control device (50) determines, taking into account the at least one sensor signal (56) of the at least one brake operating member sensor (58) of the brake system and / or of the at least one pressure sensor (60, 62) of the ESP hydraulic unit (32) and / or the brake actuation hydraulic unit (30), a motor brake torque (B ｍｏｔｏｒ ) target brake torque, and then a motor brake torque (B ｍｏｔｏｒ 3. The control device (50) of claim 1 or 2, designed and / or programmed to operate at least one of the electric motors (48) to induce a rotation of at least one of the wheels and / or at least one of the axles.

4. 4. The control device (50) according to claim 1, wherein the control device (50) is designed and / or programmed to recognize malfunctions and / or failures of a brake booster (36) of the brake actuation hydraulic unit (30), malfunctions and / or failures of at least one valve of the brake actuation hydraulic unit (30), malfunctions and / or failures of at least one sensor device of the brake actuation hydraulic unit (30), and / or malfunctions and / or failures of a first current supply of at least the brake booster (36) of the brake actuation hydraulic unit (30), of the at least one valve of the brake actuation hydraulic unit (30) and / or of the at least one sensor device of the brake actuation hydraulic unit (30) as at least one predefined error state with reference to the at least one signal (52).

5. 5. The control device (50) according to claim 1, wherein the control device (50) is designed and / or programmed to recognize a wheel lock caused by at least one of the wheel brake cylinders (42) with reference to at least one measurement signal of at least one speed sensor of at least one wheel of the vehicle, if at least one predefined error state does not occur in the brake actuation hydraulic unit (30), and to possibly switch at least one valve (68) of the ESP hydraulic unit (32) to an open state so that brake fluid can be released from the at least one locked wheel brake cylinder (42) via the at least one valve (68) switched to an open state.

6. An ESP hydraulic unit (32) for a braking system of a vehicle additionally equipped with a brake actuation hydraulic unit (30), comprising: An ESP hydraulic unit comprising a control device (50) according to any one of claims 1 to 5.

7. 7. The ESP hydraulic unit (32) of claim 6, wherein the ESP hydraulic unit (32) comprises at least one high pressure switching valve (88) via which a suction side of each of the at least one pump (40) of the ESP hydraulic unit (32) can be hydraulically connected to the brake fluid reservoir (54) of the brake system, and the control device (50) is additionally designed and / or programmed to switch the at least one high pressure switching valve (88) to an open state during activated operation of the at least one pump (40) in order to suck a brake fluid volume from the brake fluid reservoir (54).

8. In a braking system for a vehicle, An ESP hydraulic unit (32) according to claim 6 or 7, a brake actuation hydraulic unit (30) assembled to the ESP hydraulic unit (32); and a wheel brake cylinder (42) assembled to the ESP hydraulic unit (32).

9. 9. The brake system of claim 8, wherein the brake actuation hydraulic unit (30) is connectable or connected to the first current supply and the ESP hydraulic unit (32) is connectable or connected to a second current supply.

10. 10. The brake system of claim 8 or 9, wherein the brake actuation hydraulic unit (30) comprises control electronics (84) designed and / or programmed to at least activate the brake booster (36) of the brake actuation hydraulic unit (30) taking into account at least the brake operating member sensor (58) of the brake system and / or the at least one pressure sensor (60, 64) of the brake actuation hydraulic unit (30).

11. 11. The brake system of claim 10, wherein the brake booster (36) of the brake actuation hydraulic unit (30) is a brake booster upstream of a master brake cylinder (34) of the brake actuation hydraulic unit (30) or a motorized piston-cylinder device (36) integrated into the hydraulic system of the brake actuation hydraulic unit (30).

12. A method for actuating a brake system of a vehicle equipped with a brake actuation hydraulic unit (30) and an ESP hydraulic unit (32), comprising: The method includes the steps of: the brake actuation hydraulic unit (30) associated with the ESP hydraulic unit (32) is read or checked with reference to at least one signal (52) to determine whether at least one predetermined error condition has occurred; When it is determined that at least one predetermined error condition exists in the brake actuation hydraulic unit (30) after taking into account the at least one signal (52), at least one of the following steps is performed: At least one pump (40) of the ESP hydraulic unit (32) is activated to draw a fixedly set or determined brake fluid volume from a brake fluid reservoir (54) of the brake system; and / or A fixedly set or determined motor brake torque (B ｍｏｔｏｒ at least one electric motor (48) of the vehicle operable in a regenerative mode is operated to generate a regenerative energy (RE) on at least one wheel of the vehicle and / or at least one axle of the vehicle; A method comprising:

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