Motor vehicle hydraulic brake system and control unit system

Abstract

A motor vehicle hydraulic brake system (100) comprises a dual-circuit dynamic stability control system or an electronic stability control (ESC) system, the control system having a first brake circuit (I.) and a second brake circuit (II.), the first brake circuit acting on one or more first wheel brakes (130A, 130B), the second brake circuit acting on one or more second wheel brakes (130C, 130D), wherein the first brake circuit (I.) comprises a first hydraulic pressure generator (160) which can be electrically actuated for control intervention, and the second brake circuit (II.) comprises a second hydraulic pressure generator (170) which can be electrically actuated for control intervention and can be electrically actuated independently of the first hydraulic pressure generator (160). The brake system (100) further comprises an electric parking brake (EPB) system having a first actuator (140A) which can be electrically actuated and assigned to one of the first wheel brakes (130A, 130B) and a second actuator (HOB), the first actuator being electrically actuated and assigned to one of the second wheel brakes (130C, 130D). A controller (300) is also provided, which is designed to: identify impairment of at least one of the two brake circuits (I., II.) and the need for control intervention in at least one of the brake circuits (I., II.) affected by the impairment; and when impairment of the function and the need for control intervention are identified, actuate at least one of the actuators (140A, 140B) to perform or support the control intervention.

Description

Technical Field

[0001] The present disclosure relates generally to the field of motor vehicle brake systems. In particular, a motor vehicle hydraulic brake system and a control unit system for the motor vehicle hydraulic brake system are described. Background Art

[0002] Known hydraulic brake systems for motor vehicles designed as brake-by-wire (BBW) systems or equipped with electric brake boost (EBB) systems include an electrically controllable hydraulic pressure generator which, during normal braking operation, generates hydraulic pressure at the wheel brakes of the motor vehicle or boosts the hydraulic pressure generated by the driver. For this purpose, a vehicle deceleration requested by the driver at the brake pedal is detected by a sensor and converted into a control signal for the electrically controllable hydraulic pressure generator.

[0003] These types of brake systems also usually include a master cylinder which can be mechanically actuated by means of the brake pedal and via which the hydraulic fluid can likewise be transmitted to the wheel brakes. For reasons of operational safety, the master cylinder actuated by means of the brake pedal provides the necessary redundancy with respect to the electrically controllable hydraulic pressure generators of the BBW or EBB system.

[0004] Motor vehicle braking systems for autonomous or semi-autonomous driving must also be designed redundantly. However, in such situations it cannot be assumed that the driver is in the vehicle (e.g. in a remote control parking (RCP) operation) or that the driver can immediately actuate the brake pedal (e.g. when the driver is taking his eyes off the road). For this reason, braking systems for autonomous or semi-autonomous driving must include, in addition to the functional unit providing the electronically controllable main braking function, a further functional unit which redundantly implements the electronically controllable auxiliary braking function. Summary of the invention

[0005] An object of the present disclosure is to provide a motor vehicle hydraulic brake system with improved redundancy.

[0006] According to a first aspect, a motor vehicle hydraulic brake system is provided. The brake system includes a dual-circuit vehicle dynamic control system—ESC system, the vehicle dynamic control system includes a first brake circuit and a second brake circuit, the first brake circuit acts on one or more first wheel brakes, the second brake circuit acts on one or more second wheel brakes, the first brake circuit includes a first hydraulic pressure generator, the first hydraulic pressure generator is electrically controllable for control intervention, and the second brake circuit includes a second hydraulic pressure generator, the second hydraulic pressure generator is electrically controllable for control intervention and is controllable independently of the first hydraulic pressure generator. The brake system also includes an electric parking brake system—EPB system, the electric parking brake system includes an electrically controllable first actuator and an electrically controllable second actuator, the first actuator is associated with one of the first wheel brakes, and the second actuator is associated with one of the second wheel brakes. In addition, the braking system includes a controller, which is designed to: identify functional impairment of at least one of the two braking circuits and the need for control intervention in the at least one braking circuit affected by the functional impairment; and when the functional impairment and the need for the control intervention are identified, control at least one of the actuators to perform or assist the control intervention.

[0007] The braking system according to the first aspect may further include an electrically controllable third hydraulic pressure generator, the third hydraulic pressure generator being designed to generate hydraulic pressure for at least one of the two brake circuits. In this case, the controller may be designed to control the third hydraulic pressure generator to perform or assist the control intervention when the impairment of the function and the need for the control intervention are identified.

[0008] The execution of the control intervention may take place exclusively by means of the at least one controlled actuator. Alternatively, in addition to the at least one controlled actuator, another component of the brake system capable of a control intervention may also participate in the control intervention, so that the at least one actuator assists the control intervention. Such a component may be (when only part of the functionality of the affected brake circuit is impaired) for example the first hydraulic pressure generator and / or the second hydraulic pressure generator (or the third hydraulic pressure generator).

[0009] According to a second aspect, a motor vehicle hydraulic brake system includes a dual-circuit vehicle dynamic control system—ESC system, the vehicle dynamic control system including a first brake circuit and a second brake circuit, the first brake circuit acting on one or more first wheel brakes, the second brake circuit acting on one or more second wheel brakes, the first brake circuit including a first hydraulic pressure generator, the first hydraulic pressure generator being electrically controllable for control intervention, and the second brake circuit including a second hydraulic pressure generator, the second hydraulic pressure generator being electrically controllable independently of the first hydraulic pressure generator for control intervention. The brake system also includes: an electrically controllable third hydraulic pressure generator, the third hydraulic pressure generator being designed to generate hydraulic pressure for at least one of the two brake circuits; and a controller, the controller being designed to: identify functional impairment of at least one of the two brake circuits and the need for control intervention in the at least one brake circuit affected by the functional impairment; and when the functional impairment and the need for control intervention are identified, at least the third hydraulic pressure generator is controlled to perform or assist the control intervention.

[0010] In one variant of the first or second aspect, impairment of functionality of at least one brake circuit is identified as a need for a control intervention in at least one brake circuit affected by the impairment of functionality. According to another variant, the need for a control intervention is identified at a time separate from the identification of impairment of functionality of at least one brake circuit, for example at a later point in time. In this variant, controlling at least one of the actuators to perform or assist the control intervention may occur immediately upon identification of the need for a control intervention after identification of impairment of functionality of at least one brake circuit.

[0011] Examples of control interventions include one or more of the following interventions: anti-lock brake control, traction control, vehicle dynamics control in a narrow sense (eg to prevent oversteering or understeering), and brake pressure regulation for adaptive cruise control.

[0012] According to a third aspect, a motor vehicle hydraulic brake system comprises a dual-circuit vehicle dynamic control system—ESC system, the vehicle dynamic control system comprising a first brake circuit and a second brake circuit, the first brake circuit acting on one or more first wheel brakes, the second brake circuit acting on one or more second wheel brakes, the first brake circuit comprising a first hydraulic pressure generator, the first hydraulic pressure generator being electrically controllable for control intervention, and the second brake circuit comprising a second hydraulic pressure generator, the second hydraulic pressure generator being electrically controllable for control intervention and being controllable independently of the first hydraulic pressure generator. The brake system further comprises: an electrically controllable third hydraulic pressure generator, the third hydraulic pressure generator being designed to generate hydraulic pressure for at least one of the two brake circuits; and a controller, the controller being designed to: identify impairment of the function of the third hydraulic pressure generator and a braking request of the driver; and when impairment of the function of the third hydraulic pressure generator and a braking request of the driver are identified, control the first hydraulic pressure generator and / or the second hydraulic pressure generator so as to generate hydraulic pressure in at least one of the brake circuits according to the braking request of the driver.

[0013] The braking system according to the second aspect or the third aspect may further include an electric parking brake system—EPB system, the electric parking brake system having an electrically controllable first actuator and an electrically controllable second actuator, the first actuator being associated with one of the first wheel brakes, and the second actuator being associated with one of the second wheel brakes. In this case, the controller according to the second aspect may be designed to control at least one of the actuators to perform or assist the control intervention when it is recognized that at least one of the two brake circuits is impaired in function and the control intervention is required. The controller according to the third aspect may be designed to control at least one of the actuators according to the driver's braking requirement when it is recognized that the third hydraulic pressure generator is impaired in function and the driver's braking requirement is required.

[0014] The following statements apply to brake systems according to all aspects presented herein.

[0015] In one embodiment, the brake system is designed as a BBW system including the third hydraulic pressure generator and / or is equipped with an EBB system including the third hydraulic pressure generator. In an alternative embodiment, the brake system is provided with an electrically controllable vacuum brake booster, which is used as the third hydraulic pressure generator.

[0016] The BBW system can provide a mechanical disconnection of the brake pedal from the master cylinder of the brake system. In the event of a BBW system failure, this mechanical disconnection can be cancelled, thereby facilitating mechanical engagement (this is also called push-to-play (PT)).

[0017] The EBB system or the electronically controllable vacuum brake booster may not provide such a mechanical disconnection, or only provide it in certain circumstances (e.g. during regenerative braking), wherein in the case of a mechanical connection, the force acting on the master cylinder by the brake pedal is increased by using a third hydraulic pressure generator. For this purpose, the third hydraulic pressure generator may comprise a master cylinder and an electromechanical actuator, which mechanically acts on the master cylinder in addition to the brake pedal. Alternatively, the third hydraulic pressure generator may comprise a separate cylinder / piston arrangement hydraulically coupled to the master cylinder or the brake circuit, and an electromechanical actuator acting on the cylinder / piston arrangement.

[0018] The first actuator and the second actuator of the EPB system may be electrically controllable independently of each other.The actuators may be based on electromechanical principles, electropneumatic principles, or electrohydraulic principles.

[0019] A first sensor may be provided for detecting the hydraulic pressure in the first brake circuit, and a second sensor may be provided for detecting the hydraulic pressure in the second brake circuit. The signal of the first sensor may form the basis for controlling the first hydraulic pressure generator and / or the first actuator. The signal of the second sensor may form the basis for controlling the second hydraulic pressure generator and / or the second actuator.

[0020] The first brake circuit and the second brake circuit can have an identical design. An identical design can in particular relate to electrically controllable and / or hydraulically activated components installed in the brake circuits.

[0021] The braking system may include a first power supply system, which is designed to supply the first hydraulic pressure generator and / or the first actuator. Additionally or alternatively, the braking system may include a second power supply system, which is designed to supply the second hydraulic pressure generator and / or the second actuator. Separate wires and separate power sources may be associated with each supply system. The first power supply system may also be designed to supply the second hydraulic pressure generator and / or the second actuator. Alternatively or additionally, the second power supply system may be designed to supply the first hydraulic pressure generator and / or the first actuator. The first power supply system and / or the second power supply system may also be designed to supply the third hydraulic pressure generator.

[0022] At least one of these hydraulic pressure generators, in particular the first hydraulic pressure generator and / or the second hydraulic pressure generator and / or the third hydraulic pressure generator, can be designed as a motor-pump unit. Such a motor-pump unit actuable via an electric motor includes, for example, a double-acting cylinder-piston device (e.g., a plunger-type system), a single-acting cylinder-piston device (e.g., a plunger-type system), a gear pump, or a radial pump or an axial piston pump.

[0023] According to a fourth aspect, an electronic control unit system for a hydraulic brake system as presented herein according to the first, second, or third aspects is provided. The control unit system comprises: a first control unit, the first control unit being designed to control the first hydraulic pressure generator and the first actuator; and a second control unit, the second control unit being designed to control the second hydraulic pressure generator and the second actuator.

[0024] The control unit system may further comprise a third control unit, said third control unit being designed to control said third hydraulic pressure generator.Alternatively, the first control unit and / or the second control unit may be designed to control the third hydraulic pressure generator.

[0025] According to a fifth aspect, an electronic control unit system for a hydraulic brake system presented herein according to the third aspect comprises: a first control unit, which is designed to control the first hydraulic pressure generator; a second control unit, which is designed to control the second hydraulic pressure generator; and a third control unit, which is designed to control the third hydraulic pressure generator.

[0026] When an EPB system is present, the first control unit of the system according to the fifth aspect may be designed to control the first actuator, and the second control unit may be designed to control the second actuator.

[0027] The following statements apply to the control unit system according to the fourth aspect or according to the fifth aspect.

[0028] In one variant, the first control unit is designed to operate on the first power supply system and / or on the second power supply system. Alternatively or in addition, the second control unit is designed to operate on the first power supply system and / or on the second power supply system. Alternatively or in addition, the third control unit is designed to operate on the first power supply system and / or on the second power supply system. This increases the redundancy and availability of the system. For example, the control unit operates in parallel on the first power supply system and the second power supply system.

[0029] At least two of the control units (e.g., a first control unit and a second control unit) can be designed to communicate with each other via a first communication system and a second communication system. This increases the redundancy and availability of the system. For example, the control units communicate in parallel via the first communication system and the second communication system.

[0030] The first control unit and the second control unit may form a spatially adjacent control unit assembly. For example, both control units may be mounted in a shared housing, or in separate housings, but these separate housings are again mounted on the same component (eg hydraulic unit).

[0031] The first control unit may include at least one first processor, and the second control unit may include at least one second processor. At least one first processor may be provided to control the first hydraulic pressure generator and the first actuator. At least one second processor may be provided to control the second hydraulic pressure generator and the second actuator. The third control unit may include at least one third processor.

[0032] At least one first processor and at least one second processor (and optionally a third processor) can be communicatively connected to each other via a processor interface. Processor communication can cover the exchange and / or authenticity checking of control signals or measured variables (e.g., sensor data of the above-mentioned hydraulic pressure sensor or other sensors).

[0033] According to a sixth aspect, a method for operating a motor vehicle hydraulic braking system is provided, the motor vehicle hydraulic braking system having an ESC system and an EPB system, wherein the ESC system is of dual-circuit design and includes a first brake circuit and a second brake circuit, the first brake circuit acting on one or more first wheel brakes, the second brake circuit acting on one or more second wheel brakes, the first brake circuit including a first hydraulic pressure generator, the first hydraulic pressure generator being electrically controllable for control intervention, and the second brake circuit including a second hydraulic pressure generator, the second hydraulic pressure generator being electrically controllable independently of the first hydraulic pressure generator for control intervention, and the EPB system including an electrically controllable first actuator and an electrically controllable second actuator, the first actuator being associated with a first wheel brake of the first wheel brakes, and the second actuator being associated with a second wheel brake of the second wheel brakes. The method comprises the following steps: identifying impairment of function of at least one of the two brake circuits and a need for control intervention in the at least one brake circuit affected by the impairment of function; and when the impairment of function and the need for control intervention are identified, controlling at least one of the actuators to perform or assist the control intervention.

[0034] According to a seventh aspect, a method for operating an electric hydraulic brake system of a motor vehicle is provided, the electric hydraulic brake system of the motor vehicle having a vehicle dynamic control system (ESC system), the vehicle dynamic control system being of dual-circuit design and comprising a first brake circuit and a second brake circuit, the first brake circuit acting on one or more first wheel brakes, the second brake circuit acting on one or more second wheel brakes, the first brake circuit comprising a first hydraulic pressure generator, the first hydraulic pressure generator being electrically controllable for control intervention, and the second brake circuit comprising a second hydraulic pressure generator, the second hydraulic pressure generator being electrically controllable independently of the first hydraulic pressure generator for control intervention, and the brake system further comprising an electrically controllable third hydraulic pressure generator, the third hydraulic pressure generator being designed to generate hydraulic pressure for at least one of the two brake circuits. The method comprises the following steps: identifying impairment of the function of at least one of the two brake circuits and the need for control intervention in the at least one brake circuit affected by the impairment of the function; and when the impairment of the function and the need for the control intervention are identified, controlling the third hydraulic pressure generator for executing or assisting the control intervention.

[0035] The following statements apply to the method according to the sixth aspect or the seventh aspect.

[0036] Emergency braking can be performed when the function is impaired or at a later time, for example, in order to stop the vehicle as quickly as possible. In this case, control intervention can occur within the scope of emergency braking, for example, in order to maintain vehicle stability during emergency braking.

[0037] The locking of the braked wheels can be detected as a need for a control intervention, which counteracts the locking of the braked wheels. Alternatively or in addition, a vehicle dynamics control can be detected as a need for a control intervention, which is used for the vehicle dynamics control.

[0038] As described above, the brake system may further comprise an electrically controllable third hydraulic pressure generator, which is designed to generate hydraulic pressure for at least one of the two brake circuits. In this case, the method may further comprise, when the impairment of the function and the need for the control intervention are identified, controlling the third hydraulic pressure generator, i.e. for executing or assisting the control intervention.

[0039] At least one of the following events can be identified as impaired functionality of at least one of the two brake circuits: impaired functionality of the first hydraulic pressure generator and / or the second hydraulic pressure generator and / or the third hydraulic pressure generator, impaired functionality of a control unit associated with the first hydraulic pressure generator and / or the second hydraulic pressure generator and / or the third hydraulic pressure generator, and leakage of at least one of the brake circuits.

[0040] According to an eighth aspect, a method for operating a motor vehicle hydraulic brake system is provided, the motor vehicle hydraulic brake system comprising a vehicle dynamic control system (ESC) system, the vehicle dynamic control system being of dual-circuit design and comprising a first brake circuit and a second brake circuit, the first brake circuit acting on one or more first wheel brakes, the second brake circuit acting on one or more second wheel brakes, the first brake circuit comprising a first hydraulic pressure generator, the first hydraulic pressure generator being electrically controllable for control intervention, and the second brake circuit comprising a second hydraulic pressure generator, the second hydraulic pressure generator being electrically controllable independently of the first hydraulic pressure generator for control intervention, the brake system further comprising an electrically controllable third hydraulic pressure generator, the third hydraulic pressure generator being designed to generate hydraulic pressure for at least one of the two brake circuits. The method comprises the following steps: identifying impairment of the function of the third hydraulic pressure generator and a braking requirement of the driver; and when the impairment of the function and the braking requirement of the driver are identified, controlling the first hydraulic pressure generator and / or the second hydraulic pressure generator so as to generate hydraulic pressure in at least one of the brake circuits according to the braking requirement of the driver.

[0041] In addition, a computer program is provided, the computer program comprising program code, the program code is used to perform the method presented in accordance with the sixth aspect, the seventh aspect, or the eighth aspect when the program code is run on a processor (e.g., in a motor vehicle control unit). A motor vehicle control unit or control unit system (composed of a plurality of control units) is also provided, the control unit or control unit system comprising at least one processor and at least one memory, and the at least one memory comprising program code, the program code when it is executed by at least one processor causes the steps of the method provided herein to be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Further aspects, details, and advantages of the present disclosure derive from the following description of exemplary embodiments with reference to the accompanying drawings, which show the following:

[0043] Figure 1 An exemplary embodiment of a motor vehicle hydraulic brake system is shown;

[0044] Figure 2 Shown is the Figure 1 An exemplary embodiment of a control unit system of a braking system;

[0045] Figure 3A / Figure 3B shows the operation according to Figure 1A flow chart of an exemplary embodiment of a method of a braking system; and

[0046] Figure 4 Shown is shown in the Figure 3A Schematic representation of the control intervention within the context of the approach. DETAILED DESCRIPTION

[0047] Figure 1 A diagram of a hydraulic circuit of an exemplary embodiment of a motor vehicle hydraulic brake system 100 is shown.

[0048] The braking system 100 comprises an assembly 110 for generating hydraulic pressure, which can be connected to a brake pedal (not shown), and a hydraulic control module 120 (also referred to as a hydraulic control unit (HCU)) having two separate brake circuits I. and II. The braking system 100 further comprises four wheel brakes 130. Two of the four wheel brakes 130 are associated with the brake circuit I., while the other two wheel brakes 130 are associated with the brake circuit II. The association of the wheel brakes 130 with the brake circuits I. and II. occurs according to a diagonal distribution in such a way that the wheel brakes 130A and 130B on the right rear wheel (HR) and the left front wheel (VL) are respectively associated with the brake circuit I., while the wheel brakes 130C and 130D on the left rear wheel (HL) and the right front wheel (VR) are respectively associated with the brake circuit II. Any other distribution of the wheel brakes 130 on the brake circuits I. and II. is also conceivable.

[0049] The brake system 100 further includes an EPB system having two electromechanical actuators 140A, 140B which are electrically controllable separately from each other. Figure 1 It is understood that the actuators 140A, 140B include further components, such as a gear system, via which the actuators 140A, 140B act, for example, on the wheel brake cylinders.

[0050] The two actuators 140A, 140B have different associations with the four wheel brakes 130. In particular, the actuator 140A is associated with the wheel brake 130A of the right rear wheel (HR), while the actuator 140B is associated with the wheel brake 130C of the left rear wheel (HL). Of course, in other variants, the two actuators can also be associated with the wheel brakes 130B, 130D of the right front wheel (VR) or the left front wheel (VL), respectively.

[0051] The component 110 for generating hydraulic pressure comprises a master cylinder 110B and can be operated according to the EBB principle and / or the BBW principle. This means that an electrically controllable hydraulic pressure generator is installed in the component 110, which is designed to generate hydraulic pressure for at least one of the two brake circuits I. and II. This hydraulic pressure generator comprises an electric motor 110A, which acts directly or indirectly on the master cylinder 110B via a mechanical gear system (not shown) for generating hydraulic pressure. The indirect action can occur, for example, hydraulically (for example, by a gear system acting on a plunger system, the output of which is hydraulically connected to the input of the master cylinder 110B). In the following discussion, the hydraulic pressure generator installed in the component 110 is generally indicated by the reference numeral 110B.

[0052] The HCU 120 includes a dual-circuit ESC system for controlling interventions on wheel brakes 130. In particular, the ESC system includes a first electrically controllable hydraulic pressure generator 160 in a first brake circuit I. and a second electrically controllable hydraulic pressure generator 170 in a second brake circuit II. The two hydraulic pressure generators 160, 170 include electric motors 160A, 170A and pumps 160B, 170B actuated by the electric motors 160A, 170A, respectively. Each of the two pumps 160B, 170B can be designed as a multi-piston pump, a gear pump, or some other type of pump. Each pump 160B, 170B is blocked in the direction opposite to its transmission direction, as shown by the check valves at the output and input of the pumps 160B, 170B. Since the speed of each of the electric motors 160A, 170A is adjustable, the output of each of the pumps 160B, 170B may also be adjusted by appropriately controlling the associated electric motor 160A, 170A.

[0053] The two electric motors 160A, 170A and therefore the two hydraulic pressure generators 160, 170 are independently controllable. This means that each of the two hydraulic pressure generators 160 and 170 can build up hydraulic pressure in a specific brake circuit I. or II. independently of the corresponding other hydraulic pressure generator 170 or 160. This redundancy is advantageous in terms of safety considerations.

[0054] The brake system 100 operates with the aid of hydraulic fluid which is partially stored in three reservoirs 110C, 190, 200. The reservoir 110C is a pressureless reservoir which forms part of the assembly 110, while the other two reservoirs 190, 200 are installed as accumulators (e.g. low pressure accumulators, LPA) in one of the two brake circuits I., II., respectively. The two hydraulic pressure generators 160 and 170 can each draw hydraulic fluid from the associated reservoir 190 or 200 or from the central reservoir 110C.

[0055] The reservoir 110C has a larger capacity than each of the two reservoirs 190, 200. However, the volume of hydraulic fluid stored in each of the two reservoirs 190, 200 is at least sufficient to allow the vehicle to be stopped reliably (e.g., for emergency braking), also when brake pressure regulation of one or more of the wheel brakes 130 is required.

[0056] The brake circuit I. comprises a hydraulic pressure sensor 180A, which is located on the input side of the brake circuit I. in the region of the interface of the brake circuit with the assembly 110. The signal of the hydraulic pressure sensor 180A can be evaluated in conjunction with the control of the hydraulic pressure generator 110B installed in the assembly 110 and / or the control of the hydraulic pressure generator 160 installed in the brake circuit I. The evaluation and control are performed by the control unit system 300 (only in Figure 1 Similarly, another hydraulic pressure sensor 180B is installed in brake circuit II.

[0057] like Figure 1 , the two brake circuits I. and II. have an identical design with respect to the components installed therein and with respect to the arrangement of these components. Therefore, only the design and the operating principle of the first brake circuit I. will be explained in more detail below.

[0058] A plurality of valves are provided in the brake circuit I. These valves can be actuated by electromagnets and take the form of actuation in the non-actuated state, i.e., in the non-electrically controlled state. Figure 1. In these basic positions, the valve couples the assembly 110, in particular the master cylinder 110B, to the wheel brakes 130. Thus, even in the presence of an impairment of the electrical supply function (e.g. a failure) and a concomitant failure of the hydraulic pressure generator 110B, the driver can still build up hydraulic pressure at the wheel brakes 130 by means of the brake pedal acting on the master cylinder 110A. However, in the case of an EBB implementation, this hydraulic pressure does not increase, or in the case of a BBW implementation, a mechanical coupling of the brake pedal to the master cylinder 110A (push-action (PT) operation) occurs. In contrast, during BBW operation, the master cylinder 110A is fluidically disconnected from the brake circuit I in a known manner.

[0059] The plurality of valves comprises two 2 / 2-way valves 210, 220 which allow the two wheel brakes 130A and 130B to be disconnected from the assembly 110. In particular, the valve 210 is provided for disconnecting the wheel brakes 130A, 130B from the assembly 110 in the electrically controlled state during a control intervention in at least one of the two wheel brakes 130A, 130B by means of the hydraulic pressure generator 160. The valve 220 in its electrically controlled state allows the hydraulic fluid to be sucked in or replenished from the reservoir 110C (for example, in the case of a long control intervention, if the reservoir 190 is completely emptied). In addition, in this electrically controlled state, the pressure at the wheel brakes 130A, 130B can be reduced, in that the hydraulic fluid can be caused to flow back from the wheel brakes 130A, 130B into the pressure-free reservoir 110C.

[0060] The hydraulic connection of the wheel brakes 130A, 130B to the assembly 110 and the hydraulic pressure generator 160 is determined by four 2 / 2-way valves 230, 240, 250, 260, which in the non-actuated state, i.e. not electrically controlled, assume the same hydraulic connection as described above. Figure 1 . This means that the two valves 230 and 260 each adopt their flow-through position, while the two valves 240 and 250 each adopt their blocking position. The two valves 230 and 240 form a first valve arrangement associated with wheel brake 130B, while the two valves 250 and 260 form a second valve arrangement associated with wheel brake 130A.

[0061] As explained below, the two valves 210 and 220, the two valve devices 230, 240 and 250, 260 and the hydraulic pressure generator 160 are each designed to be controlled for a wheel brake pressure control intervention at a specific wheel brake 130A, 130B. The control of the two valves 210 and 220, the control of the two valve devices 230, 240 and 250, 260 and the control of the hydraulic pressure generator 160 takes place within the scope of the control intervention by means of the control unit system 300. For example, the control unit system 300 implements a wheel brake pressure control intervention of a vehicle dynamics control system, such as an electronic stability control (ESC), wherein, according to the present disclosure, the vehicle dynamics control system also includes an anti-lock braking system (ABS), a traction control system (TCS), and brake pressure regulation for an adaptive cruise control (ACC).

[0062] The purpose of anti-lock brake control is to prevent wheel locking during braking. For this purpose, it is necessary to modulate the hydraulic pressure in the wheel brakes 130A, 130B individually. This occurs by alternatingly regulating the pressure build-up phase, the pressure holding phase, and the pressure reduction phase in a chronological order, which is caused by appropriate control of the valve devices 230, 240 and 250, 260 of the two wheel brakes 130B and 130A, and optionally appropriate control of the hydraulic pressure generator 160.

[0063] During the pressure build-up phase, the valve devices 230, 240 and 250, 260 each assume their basic position, so that an increase in the brake pressure in the wheel brakes 130A, 130B (e.g. for BBW braking) can occur by means of the hydraulic pressure generator 160. For a pressure maintenance phase at one of the wheel brakes 130B or 130A, only the valve 230 or 260 is correspondingly controlled, i.e. switched to its blocking position. Since no control of the valve 240 or 250 occurs, the valve remains in its blocking position. As a result, the corresponding wheel brake 130B or 130A is hydraulically decoupled, so that the hydraulic pressure present in the wheel brake 130B or 130A remains constant. During the pressure reduction phase, the valve 230 or 260 and the valve 240 or 250 are controlled; i.e., the valve 230 or 260 is switched to its blocking position and the valve 240 or 250 is switched to its flow-through position. Thus, hydraulic fluid can flow out of the wheel brake 130B or 130A in the direction of the reservoirs 110C and 190 in order to reduce the hydraulic pressure present in the wheel brake 130A or 130B.

[0064] Other control interventions during normal braking maneuvers occur in an automated manner and typically independently of the driver's actuation of the brake pedal. Such automated regulation of the wheel brake pressure occurs, for example, in conjunction with traction control, which prevents individual wheels from spinning during launch maneuvers by targeted deceleration, and in conjunction with vehicle dynamics control in the narrow sense, which adapts the vehicle's behavior to the boundary region of the driver's intention and road conditions by targeted deceleration of individual wheels, or in conjunction with adaptive cruise control, which, among other things, keeps the host vehicle at a certain distance from the vehicle ahead by automatic braking.

[0065] When automatic hydraulic pressure regulation is being performed, hydraulic pressure can be built up at at least one of the wheel brakes 130A or 130B by controlling the hydraulic pressure generator 160. The valve devices 230, 240 and 250, 260 for the hydraulic pressure generator 160, which are respectively associated with the wheel brakes 130B, 130A, first take their Figure 1 Fine adjustments or modulations of the hydraulic pressure may be made by appropriate control of the hydraulic pressure generator 160 and the valves 230, 240 and 250, 260 associated with the wheel brakes 130B and 130A, respectively, as explained above in connection with the ABS control.

[0066] The hydraulic pressure regulation usually takes place by the control unit system 300 as a function of the following measured variables: on the one hand, measured variables describing the vehicle behavior (e.g. wheel speed, yaw rate, lateral acceleration, etc.) and on the other hand, measured variables describing the driver's request (e.g. actuation of the brake pedal, steering wheel angle, etc.). The driver's deceleration request can be determined, for example, by means of a path sensor connected to the brake pedal or to the input element of the master cylinder 110A. Alternatively or in addition, the brake pressure generated by the driver in the master cylinder 110A can be used as a measured variable describing the driver's request, which brake pressure is then detected by means of the sensor 180A (and the corresponding sensor 180B associated with the brake circuit II.) and can optionally undergo a plausibility check.

[0067] Figure 2 Shows Figure 2 [sic; 1] is an exemplary embodiment of a control unit system 300. Figure 2 As shown in FIG. 1 , the control unit system 300 includes: a first control unit 302, which is designed to control the hydraulic pressure generator 160 and the EPB actuator 140A; and a second control unit 304, which is designed to control the hydraulic pressure generator 170 and the EPB actuator 140B. Figure 1As explained, this control can take place based on a plurality of measured variables detected by sensors.

[0068] In accordance with Figure 2 In the exemplary embodiment of the present invention, the two control units 302 and 304 are designed as a spatially adjacent control unit assembly 306. Thus, the two control units 302 and 304 can be accommodated in a shared housing, but can include separate processors 302A, 304A for processing measured variables and for controlling the associated components 140A, 160 and 140B, 170, respectively. For data exchange, for example in conjunction with a plausibility check of measured variables and / or control signals, the respective processors 302A, 304A of the two control units 302, 304 are communicatively connected to each other via a processor interface 308. In the exemplary embodiment, the processor interface 308 is designed as a serial-parallel interface (SPI).

[0069] The control unit system 300 further comprises a third control unit 310, which is designed to control the hydraulic pressure generator 110B installed in the assembly 310 and, therefore, in particular the electric motor of the hydraulic pressure generator. Depending on the design of the brake system 100, this control can take place according to the EBB principle or the BBW principle. The control unit 310 together with the two other control units 302 and 304 can form a spatially adjacent control unit assembly, or can be arranged spaced apart from the two other control units. In one embodiment, the housing of the control unit 310 is integrated in the assembly 110.

[0070] like Figure 2 As shown in FIG. 1 , two parallel power supply systems K30 - 1 and K30 - 2 are provided. Each of the two supply systems K30 - 1 and K30 - 2 includes a power supply and associated power supply lines. Figure 2 In an exemplary embodiment of the present invention, the supply system K30-1 is designed to supply the EPB actuator 140A and the hydraulic pressure generator 160, while the parallel supply system K30-2 is designed to supply another EPB actuator 140B and the hydraulic pressure generator 170. In another exemplary embodiment, the EPB actuator 140A and the hydraulic pressure generator 160 can be additionally (i.e. redundantly) supplied by the supply system K30-2, and the EPB actuator 140B and the hydraulic pressure generator 170 can be additionally supplied by the supply system K30-1. In this way, the system redundancy is further increased.

[0071] Each of the three control units 302, 304, and 310 is redundantly supplied by the supply system K30-1 and also by the supply system K30-2. For this purpose, each of the three control units 302, 304, 310 can be provided with two separate supply connectors, which are associated in each case with one of the two supply systems K30-1 or K30-2.

[0072] Also like Figure 2 As shown in FIG. 1 , two parallel communication systems, bus 1 and bus 2, are redundantly arranged, and in an exemplary embodiment, each of these communication systems is designed as a vehicle bus (e.g., according to the CAN or LIN standard). The three control units 302, 304, and 310 can communicate with each other via each of the two communication systems, bus 1 and bus 2.

[0073] In accordance with Figure 2 In an exemplary embodiment of the invention, the control of the components 140A, 160 and 140B, 170 takes place by means of two control units 302 and 304, respectively, and the control of the hydraulic pressure generator 110B installed in the assembly 110 takes place by means of the control unit 310, in such a way that the respective control unit 302, 304, 310 switches on and off the power supply to the appropriate components and optionally modulates it (for example, by pulse width modulation). In another exemplary embodiment, one or more of these components, in particular the EPB actuators 140A, 140B, can be connected to one or both of the communication system buses 1, 2. In this case, the control of these components by means of the associated control units 302, 304, 310 then takes place via the respective communication system buses 1, 2. In addition, in this case, the respective components can be continuously connected to one or both of the supply systems K30-1, K30-2.

[0074] The following references Figure 3A Flowchart 400 explains the operation according to Figure 1 An exemplary embodiment of a method for a braking system 100 of the present invention. The method may be performed by Figure 2 The control unit system 300 shown in FIG. 1 or by a control unit system configured in some other manner.

[0075] The method starts in step 402 with the identification of a functional impairment of at least one of the brake circuits I., II. The functional impairment can be identified by means of a sensor installed in the brake system 100, such as the hydraulic pressure sensor 180A or 180B, or in some other way. Thus, a leak in the brake circuit I. and the accompanying functional impairment of the brake circuit I. can be identified by the detection of a pressure drop by the hydraulic pressure sensor 180A. In addition, functional impairment of at least one of the two hydraulic pressure generators 160, 170 or functional impairment of the control unit 302, 304 associated with the corresponding hydraulic pressure generator 160, 170 can be identified as a functional impairment of the corresponding brake circuit I., II. In extreme cases, the functional impairment can lead to a complete failure of the brake circuit I., II. in question.

[0076] In a further step 404, a need for a control intervention in the brake circuit affected by the impaired functionality is identified. Steps 402 and 404 can be performed in any given order or can also be performed simultaneously. Thus, the impaired functionality of the brake circuit identified in step 402 can itself represent a need for a control intervention according to step 404. In another embodiment, the need for a control intervention according to step 404 is different from the impaired functionality of the brake circuit identified in step 402. Thus, for example, the locking of the braked wheels or the need for a control intervention in the narrow sense (see, for example, the following description) can be considered. Figure 4 ) as a control intervention requirement according to step 404. The locking of the corresponding braked wheels and / or the corresponding driving dynamics control requirement may occur in conjunction with emergency braking. This emergency braking may occur as a reaction to the impairment of the brake circuit function detected in step 402 or as a reaction to some other event (e.g., an impending rear-end collision or a person entering the road).

[0077] If both an impairment of the brake circuit function (step 402) and a need for a control intervention (step 404) have been identified, at least one of the EPB actuators 140A, 140B and / or the hydraulic pressure generator 110B installed in the assembly 110 is controlled in step 406 in order to perform or assist the control intervention. For control intervention assistance, in addition to controlling one or more of the above-mentioned components, another component is additionally controlled. If the hydraulic pressure generator 170 is affected by the brake circuit failure, this other component can be, for example, the hydraulic pressure generator 160 (or vice versa).

[0078] The following references Figure 3B Flowchart 500 explains the operation according to Figure 1 Another exemplary embodiment of a method for a braking system 100 of the present invention. The method may be performed by Figure 2The control unit system 300 shown in FIG. 1 or by a control unit system configured in some other manner.

[0079] The method begins in step 502 with the identification of a hydraulic pressure generator 110B configured for EBB implementation and / or BBW implementation that is impaired in function. Impaired function may be identified by a sensor installed in the brake system 100 (e.g., a hydraulic pressure sensor 180A or 180B), or in some other way. Impaired function may be a failure of the electric motor 110A (including a failure of its power supply) or a failure of the control unit 310. In another step 504, the driver's braking request is identified. This identification may occur by a sensor installed at the brake pedal (e.g., a path sensor). If both an impairment of function (step 502) and a need for a driver's braking request (step 504) have been identified, at least one of the hydraulic pressure generators 160, 170 is controlled in step 506 according to the driver's braking request. This control may be used to assist the braking force (EBB implementation) or to generate a braking force without a driver's force component (BBW implementation).

[0080] according to Figure 3A Step 406 or according to Figure 3B The control concept of step 506 and Figure 1 and Figure 2 The redundancy shown in FIG. 1 allows safety-related control interventions or brake force build-up to be performed even if one of the brake circuits I., II. is functionally impaired or the hydraulic pressure generator 110B is functionally impaired. Figure 4 Schematic display of Figure 3A The situation explains this situation.

[0081] Figure 4 1 shows an auxiliary control intervention by the EPB actuator 140B in the case of an understeering vehicle when the brake circuit II. is impaired in function (e.g. due to a leak in the hydraulic line or an impaired function of the hydraulic pressure generator 170). Figure 3A If, in step 402 of the method shown in FIG. , it is identified that the brake circuit II. is impaired in function, and in addition in step 404 a need for control intervention due to understeer is identified, then in step 406 the control unit 304 selectively controls the EPB actuator 140B in order to generate a yaw moment by means of a unilateral control intervention, which yaw moment counteracts the understeer.

[0082] It should be noted that Figure 4 The control intervention is shown only by way of example, and step 406 may also be performed in conjunction with other control interventions. Figure 4In the case of a brake circuit II., similar to the case of a brake circuit II., the function is impaired (eg, the hydraulic pressure generator 170 is impaired), the hydraulic pressure generator 110B may be controlled to perform or assist in accordance with Figure 3A The control intervention in step 406 of FIG. 4 is performed. For this purpose, the valve installed in the brake circuit II. (see Figure 1 ) is positioned to allow for unilateral control intervention at the left rear wheel ( Figure 4 ). A corresponding control of the hydraulic pressure generator 110B can occur in addition to or instead of the control of the EPB actuator 140B described above. The corresponding braking torques of the EPB actuator 140B and the hydraulic pressure generator 110B can therefore be superimposed in the case of such a control intervention.

[0083] The three steps 402, 404 and 406 can be performed by the control unit 304. Alternatively, the control unit 304 can only perform step 406, while steps 402 and 404 are performed by another control unit, which sends a signal to the control unit 406 indicating that, for example, the EPB actuator 140B must be controlled. In contrast, the other brake circuit I. is hydraulically functional and can be used additionally for longitudinal and / or lateral control of the vehicle if necessary. In this regard, the corresponding braking torques can be superimposed. In this case, for example, a corresponding control of the hydraulic pressure generator 160 can take place by the control unit 302.

[0084] The concepts described herein can be implemented in particular in conjunction with highly automated (i.e. autonomous or semi-autonomous) driving in order to meet safety function requirements. Thus, for "Level 4" highly automated driving, it is assumed that the driver himself can only take over control of the vehicle again after a certain waiting period. If a fault occurs in the brake system 100 during this waiting period, the technical teaching presented herein therefore allows the basic functionality to be improved compared to manual driving.

Claims

1. A motor vehicle hydraulic brake system (100), comprising: A vehicle dynamic control system (ESC) system with a dual-circuit design, the vehicle dynamic control system comprising a first brake circuit (I.) and a second brake circuit (II.), the first brake circuit (I.) acting on one or more first wheel brakes (130A, 130B), the second brake circuit (II.) acting on one or more second wheel brakes (130C, 130D), the first brake circuit (I.) comprising a first hydraulic pressure generator (160), the first hydraulic pressure generator (160) being electrically controllable for control intervention, and the second brake circuit (II.) comprising a second hydraulic pressure generator (170), the second hydraulic pressure generator (170) being electrically controllable independently of the first hydraulic pressure generator (160) for control intervention; Electric parking brake system - EPB system, the electric parking brake system includes: an electrically controllable first actuator (140A), the first actuator (140A) being associated with a first wheel brake of the first wheel brakes (130A, 130B), and an electrically controllable second actuator (140B), the second actuator (140B) being associated with one of the second wheel brakes (130C, 130D); and A controller, the controller being designed to: identifying a functional impairment of at least one of the first brake circuit (I.) and the second brake circuit (II.) and a need for a control intervention in the at least one brake circuit affected by the functional impairment; and When the impairment of the function and the need for the control intervention are identified, at least one of the first actuator (140A) and the second actuator (140B) is controlled to perform or assist the control intervention, Wherein, the motor vehicle hydraulic brake system further comprises: a first power supply system (K30-1) designed to supply the first hydraulic pressure generator (160) and the second hydraulic pressure generator (170); and a second power supply system (K30-2), the second power supply system (K30-2) being designed to supply the second hydraulic pressure generator (170) and the first hydraulic pressure generator (160), Wherein, the braking system further comprises: an electrically controllable third hydraulic pressure generator (110B), the third hydraulic pressure generator (110B) being designed to generate hydraulic pressure for at least one of the first brake circuit (I.) and the second brake circuit (II.), The controller is designed to control the third hydraulic pressure generator (110B) to perform or assist the control intervention when the impairment of the function and the need for the control intervention are identified.

2. The motor vehicle hydraulic brake system according to claim 1, wherein: The braking system (100) is also designed as a brake-by-wire system (BBW system) including the third hydraulic pressure generator (110B), and / or is equipped with an electric brake boosting system (EBB system) including the third hydraulic pressure generator (110B).

3. A motor vehicle hydraulic brake system according to claim 1 or 2, wherein: The first actuator (140A) and the second actuator (140B) are electrically controllable independently of each other.

4. The motor vehicle hydraulic brake system according to claim 1 or 2, wherein: A first sensor (180A) and a second sensor (180B) are provided, wherein the first sensor (180A) is used to detect the hydraulic pressure in the first brake circuit (I.), and the second sensor (180B) is used to detect the hydraulic pressure in the second brake circuit (II.).

5. The motor vehicle hydraulic brake system according to claim 1 or 2, wherein: The first brake circuit (I.) and the second brake circuit (II.) are of identical design.

6. The motor vehicle hydraulic brake system according to claim 1 or 2, wherein: The first power supply system (K30-1) is also designed to supply the first actuator (140A) and / or the second actuator (140B); and / or The second power supply system (K30-2) is also designed to supply the second actuator (140B) and / or the first actuator (140A).

7. The motor vehicle hydraulic brake system according to claim 1 or 2, wherein: The first power supply system (K30-1) and / or the second power supply system (K30-2) are also designed to supply the third hydraulic pressure generator (110B).

8. The motor vehicle hydraulic brake system according to claim 1 or 2, wherein: At least one of the first hydraulic pressure generator (160), the second hydraulic pressure generator (170) and the third hydraulic pressure generator (110B) is designed as a motor-pump unit.

9. An electronic control unit system (300) for a motor vehicle hydraulic brake system (100) according to any one of claims 1 to 8, comprising a first control unit (302), the first control unit (302) being designed to control the first hydraulic pressure generator (160) and the first actuator (140A); a second control unit (304) designed to control the second hydraulic pressure generator (170) and the second actuator (140B); and A third control unit (310), the third control unit (310) is designed to control the third hydraulic pressure generator (110B).

10. The electronic control unit system according to claim 9, wherein: The first control unit (302) is designed to operate on the first power supply system (K30-1) and / or on the second power supply system (K30-2).

11. The electronic control unit system according to claim 9 or 10, wherein: The second control unit (304) is designed to operate on the first power supply system (K30-1) and / or on the second power supply system (K30-2).

12. The electronic control unit system according to claim 9 or 10, wherein: The third control unit (310) is designed to operate by means of the first power supply system (K30-1) and / or by means of the second power supply system (K30-2).

13. The electronic control unit system according to claim 9 or 10, wherein: At least two of the first control unit (302), the second control unit (304) and the third control unit (310) are designed to communicate with each other via a first communication system and a second communication system.

14. The electronic control unit system according to claim 9 or 10, wherein: The first control unit (302) and the second control unit (304) form a spatially adjacent control unit assembly (306).

15. The electronic control unit system according to claim 14, wherein: The first control unit (302) includes a first processor (302A) and the second control unit (304) includes a second processor (304A), the first processor (302A) and the second processor (304A) being communicatively connected to each other via a processor interface (308).

16. A method for operating an electro-hydraulic brake system (100) for a motor vehicle, the electro-hydraulic brake system for a motor vehicle having a vehicle dynamics control system (ESC system) and an electric parking brake system (EPB system), wherein: The ESC system is of dual-circuit design and comprises a first brake circuit (I.) and a second brake circuit (II.), the first brake circuit acting on one or more first wheel brakes (130A, 130B), the second brake circuit acting on one or more second wheel brakes (130C, 130D), the first brake circuit (I.) comprising a first hydraulic pressure generator (160), the first hydraulic pressure generator (160) being electrically controllable for control intervention, and the second brake circuit (II.) comprising a second hydraulic pressure generator (170), the second hydraulic pressure generator (170) being electrically controllable independently of the first hydraulic pressure generator (160) for control intervention, and wherein the EPB system comprises an electrically controllable first actuator (140A) and an electrically controllable second actuator (140B), the first actuator (140A) and one of the first wheel brakes (130A, 130B) being electrically controllable. The motor vehicle electric hydraulic brake system (100) further comprises: a first power supply system (K30-1), the first power supply system (K30-1) being designed to supply the first hydraulic pressure generator (160) and the second hydraulic pressure generator (170); and a second power supply system (K30-2), the second power supply system (K30-2) being designed to supply the second hydraulic pressure generator (170) and the first hydraulic pressure generator (160), the brake system (100) further comprises an electrically controllable third hydraulic pressure generator (110B), the third hydraulic pressure generator (110B) being designed to generate hydraulic pressure for at least one of the first brake circuit (I.) and the second brake circuit (II.), the method comprising the following steps: identifying (402, 404) a functional impairment of at least one of the first brake circuit (I.) and the second brake circuit (II.) and a need for a control intervention in the at least one brake circuit affected by the functional impairment; and When the impairment of the function and the need for the control intervention are identified, controlling (406) at least one of the first actuator (140A) and the second actuator (140B) to perform or assist the control intervention, The method further comprises the following steps: When the impairment of the function and the need for the control intervention are identified, the third hydraulic pressure generator (110B) is controlled to perform or assist the control intervention.

17. The method according to claim 16, wherein: If the impairment of the function is detected, emergency braking is performed and the control intervention takes place within the scope of the emergency braking.

18. The method according to claim 16 or 17, wherein: The locking of the braked wheels is detected as a requirement for a control intervention, and the control intervention counteracts the locking of the braked wheels.

19. The method according to claim 16 or 17, wherein: A vehicle dynamics control is identified as a need for a control intervention, and the control intervention is used for the vehicle dynamics control.

20. The method according to claim 16 or 17, wherein: At least one of the following events is identified as an impairment of the functionality of at least one of the first brake circuit (I.) and the second brake circuit (II.): - the function of the first hydraulic pressure generator (160) and / or the second hydraulic pressure generator (170) is impaired; - the functionality of a first control unit (302) associated with the first hydraulic pressure generator (160) and / or a second control unit (304) associated with the second hydraulic pressure generator (170) is impaired; and - a leak in at least one of the first brake circuit (I.) and the second brake circuit (II.).

21. A computer program product, comprising a computer program having a program code for executing the method according to one of claims 16 to 20 when the computer program is run on at least one processor (302A, 304A).

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