CN108944881B

CN108944881B - Electronically voltage-regulatable brake device and method for controlling same

Info

Publication number: CN108944881B
Application number: CN201810480229.8A
Authority: CN
Inventors: F.帕洛姆巴; H.贝林; T.弗里德里希; V.科考雷克
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-05-18
Filing date: 2018-05-18
Publication date: 2022-07-08
Anticipated expiration: 2038-05-18
Also published as: CN108944881A; DE102018205957A1

Abstract

An electronically voltage-regulatable brake device and a method for controlling an electronically voltage-regulatable brake device. The brake system is equipped with a pressure medium unit for setting and regulating the brake pressure of the individual wheels at the wheel brakes, which are each associated with one of the brake circuits of the brake system and are connected to the pressure medium unit. For this purpose, the pressure medium assembly has an electronically controllable pump unit and an electronically controllable valve device. The latter comprises, for each of the wheel brakes, an inlet valve which is assigned to and controls the inflow of pressure medium to the wheel brake and an outlet valve which controls the outflow of pressure medium out of the wheel brake. Each wheel brake of the brake system is in contact with at least two brake circuits, wherein the pump unit and the valve device of one brake circuit can be actuated independently of the pump unit and the valve device of the respective other brake circuit.

Description

Electronically voltage-regulatable brake device and method for controlling same

Technical Field

The invention relates to an electronically voltage-controllable brake system for an autonomously traveling motor vehicle, and to a method for controlling an electronically voltage-controllable brake system.

Background

The electronically adjustable brake systems of conventional motor vehicles are equipped with pressure medium assemblies for setting and adjusting the brake pressure of individual wheels at wheel brakes, which are each associated with one of a plurality of brake circuits of the brake system and are connected to the pressure medium assemblies. For this purpose, the pressure medium assembly has an electronically controllable pump unit at each brake circuit and an electronically controllable valve device at each connected wheel brake. The latter comprises an inlet valve and an outlet valve, wherein the two valves can also be combined into a valve unit. The inlet valve controls the inflow of pressure medium to the associated wheel brake, and the outlet valve controls the outflow of pressure medium from the associated wheel brake. The pump unit and the valves are controlled by an electronic control unit adapted to the slip ratio prevailing at the wheels of the vehicle, which detects and evaluates vehicle-side sensor signals for this purpose.

For brake systems that can regulate slip in a motor vehicle, the designations ABS, ASR or ESP brake system are also used depending on their functional range. The hydraulic circuit diagram of such a vehicle brake system is disclosed, for example, in the yellow handbook entitled "ride stability system", ISBN-3-7782-2026-8, pages 91 and 92, of robert bosch limited. On page 91, a hydraulic circuit diagram of a vehicle brake system with an anti-lock braking system (ABS) is shown, and on page 92, a hydraulic circuit diagram of a vehicle brake system with a driving stability control system (ESP) modified thereto is shown.

These known electronically pressure-adjustable brake systems are designed for control by the driver. This means that in the event of a fault, i.e. for example in the on-board electrical system of the vehicle, the driver can always perform the braking process manually. The so-called mechanical or hydraulic retraction level (ruckfillebene) determines the layout of such a vehicle brake system.

Currently, there is a strong development activity in the field of autonomous, i.e. driver-free, driving motor vehicles. However, in autonomously traveling motor vehicles, the attention of the passengers is not guaranteed during the driving operation, so that in an emergency situation it is not possible to assume the intervention of the passengers. Therefore, all safety-relevant systems of such vehicles, i.e. in particular the steering system and the braking system, have to be implemented redundantly. The redundantly implemented safety system allows the vehicle to be operated in a safe state even in the event of a failure of one of the systems, so that no manual intervention by the passengers is required. However, the redundant brake systems have a significantly higher construction outlay and correspondingly higher construction space requirements than conventional brake systems, which in addition to this also leads to higher costs.

Disclosure of Invention

In contrast, an electronically voltage-adjustable brake system has the following advantages: with which a redundant brake system is realized in a particularly compact and cost-effective manner, which is suitable for use in autonomously traveling motor vehicles. The proposed brake system is constructed from components which are conventional per se and can be actuated electro-hydraulically and is divided into brake circuits having a hydraulic configuration which is known and has been tested several times.

By means of a simple, preferably spring-free check valve, which is arranged downstream of each inlet valve associated with the wheel brake, it is prevented that the brake pressure generated by the first pump associated with the first brake circuit can be reduced in an undesirable manner via the second inlet valve of the second brake circuit, which second inlet valve is assigned to the second pump. Conventional driver-controlled brake systems for motor vehicles do not have such a non-return valve.

The pressure medium assembly of the proposed brake system can be formed from a plurality of subassemblies, which can be represented in terms of their design by simple implementation of structural changes at known pressure medium assemblies. Thus, the sub-assembly can be manufactured and assembled on existing production equipment. In principle, the pressure medium assemblies used have a simpler construction than even the pressure medium assemblies of known brake systems, since in their case of failure of the brake system, hydraulic or mechanical intervention (Durchgriff) for the driver can be dispensed with. In addition, the proposed brake system does not have a master brake cylinder or a brake pedal. The pump inlets of the pumps used are each connected directly to a pressure medium reservoir. Due to the lack of necessary driver involvement during braking, it is possible to dispense with the need to replace valves for controlling the pressure medium connection between the master brake cylinder and the wheel brakes, and the functionality of the ride stability control system can therefore be represented in the pump housing by the dimensions of the pump housing of the anti-lock control system.

The subassemblies used preferably have the same structure as one another and can also control the braking process alternatively or in alternation with one another. This reduces the load on the assembly over its service life and leads to a cost reduction when its components are correspondingly adapted.

Drawings

Embodiments of the invention are illustrated in the drawings and described in detail in the following description.

Fig. 1 shows a hydraulic circuit diagram of a brake system which can be regulated electronically for slip, according to a first exemplary embodiment of the invention;

fig. 2 shows a hydraulic circuit diagram according to a first modification of the present invention;

fig. 3 shows a hydraulic circuit diagram according to a second modification of the present invention; and

fig. 4 shows a hydraulic circuit diagram of the brake system when the brake system is in an operating state in which the pressure build-up is dynamically increased.

Detailed Description

The electronically pressure-adjustable brake system 10 shown in fig. 1 is formed by a pressure medium assembly 12, which is divided into a total of two

subassemblies

12a, 12 b. The two

subassemblies

12a, 12b are identical to one another, so that further statements can be restricted to the subassembly 12 a.

The subassembly 12a comprises a so-called pump housing 14 which is equipped with electronically controllable components for controlling the pressure medium. In this connection, two pumps 16 are mentioned, which can be operated by a common drive motor 18. The pump 16 can alternatively be a single-piston pump or a multi-piston pump, respectively, but can also be a gear pump or the like. Each pump 16 supplies the associated

brake circuit

20a, 20b with pressure medium and for this purpose is connected directly, with its suction side, to a storage tank 22 which is arranged outside and in contact with the pump housing 14, or for this purpose is connected directly in parallel to a return structure 24 of the brake circuit 20. The pressure side of the pump 16 is connected to one of the wheel brakes 30 of the brake circuit 20 via an inlet valve 26 and via a non-return valve 28, which is connected in series with the inlet valve 26 in the flow direction. The check valve 28 is preferably spring-free and, as soon as the pressure level downstream of the check valve 28 has a higher value than upstream of the check valve 28, it opens in the flow direction from the inlet valve 26 to the wheel brake 30 or closes in the opposite direction. At each brake circuit 20, the brake system 10 has a total of two wheel brakes 30 and thus two inlet valves 26. The inlet valve 26 controls the inflow of pressure medium into the wheel brake 30 and thus controls the brake pressure build-up.

The wheel brakes 30 of a brake circuit 20 are arranged on the wheels of the vehicle which are diagonally opposite one another, so that, according to the present illustration, the brake system is a brake system 10 with a diagonal division of the

brake circuits

20a, 20 b.

In addition to the inlet valve 26, an outlet valve 32 is associated with each wheel brake 30 of the brake circuit 20. The outlet valve controls the outflow of pressure medium from the associated wheel brake 30 into the reservoir 22 and thus controls the brake pressure reduction. For this purpose, the outlet valve 32 is arranged in the return structure 24, which is in contact with the brake circuit 20 on the one hand between the check valve 28 downstream of the inlet valve 26 and the wheel brake 30 associated with the inlet valve 26 and on the other hand leads directly to the reservoir 22 or to an interface for the reservoir at the pump housing 14. The outlet valves 32 are embodied as proportional control valves and can be switched from a closed starting position into a flow position as a function of their electronic actuation in a plurality of intermediate positions. In contrast, the inlet valve 26 is a switching valve which can be switched by electronic actuation from its normally open initial position into a latched position without taking up a stable intermediate position in this case. However, this embodiment of the inlet valve 26 is only to be seen as an example; it is also conceivable to implement the inlet valve as a proportional valve, for example, if the pressure control in the brake circuit 10 must be given a higher priority than the costs.

Each

subassembly

12a, 12b has two

brake circuits

20a, 20b equipped or embodied in this way. The coupling of the conductive pressure media of the two

subassemblies

12a, 12b is achieved by: one of the

brake circuits

20a, 20b of one subassembly 12a is connected in parallel with the

respective brake circuit

20a, 20b of the other subassembly 12 b. The respective connection point between the

brake circuits

20a, 20b is located directly upstream of the wheel brake 30 of this

brake circuit

20a, 20b, i.e. between a branch of the return structure 24 and a branch of the wheel brake 30 connected to the

brake circuits

20a, 20 b.

According to the embodiment of fig. 1, each

subassembly

12a, 12b is assigned its own storage tank 22. However, it is also conceivable for the two

subassemblies

12a, 12b to supply themselves with pressure medium from the common storage tank 22 or to feed pressure medium back to the common storage tank 22.

The described vehicle brake device works in the following manner:

when a braking process is initiated, the drive motor 18 is electronically controlled by an electronic control unit 34 associated with the

subassemblies

12a, 12b, as a result of which this drive motor actuates the pump 16 associated with the brake circuit 30. These pumps suck pressure medium directly from the reservoir 22 and deliver it via the inlet valve 26 and the associated non-return valve 28 to the wheel brakes 30 of the

respective brake circuit

20a, 20 b. In this case, the outlet valve 32 is kept closed, so that a brake pressure build-up occurs in the wheel brakes 30 until a desired brake pressure level predefined by the electronic control unit 34 is reached. As soon as this brake pressure level is reached, the inlet valve 26 is switched into the latched position and the actuation of the drive motor 18 is optionally canceled.

Due to the coupling of the

brake circuits

20a, 20b of one subassembly 12a to the

brake circuits

20a, 20b of the respective other subassembly 12b, the pressure medium supplied by the pump 16 of one subassembly 12a also flows over to the respective other subassembly 12 b. In this case, the non-return valve 28, which is dependent on the inlet valve 26 in terms of flow technology, together with the non-flow-closed outlet valve 32 of the other subassembly 12b prevents pressure medium from escaping through the inlet or

outlet valve

26, 32 toward the storage tank 22 and thus can impair the brake pressure build-up.

The reduction of the brake pressure set at the wheel brakes 30 is achieved by electronic actuation of the outlet valves 32. In accordance with the electronic actuation, the outlet valve 32 releases a variably settable opening cross section, through which the pressure medium can flow out of the wheel brake 30 toward the reservoir 22 and thus a desired brake pressure adaptation can take place in the wheel brake 30. This brake pressure adaptation can be carried out both as a function of the changing slip ratio at the wheels of the vehicle (Schlupfverh ä ltnisse) or as a function of the changing traffic conditions and is determined or carried out in each case by the electronic controller 34 assigned to the

subassemblies

12a, 12 b. Of course, for redundancy of the brake system 10, each control unit 34 must be coupled to its own voltage supply.

The control of the brake system 10 with the pressure medium unit consisting of the two

subassemblies

12a, 12b can be carried out in such a way that successive braking processes are alternately controlled by one subassembly 12a and then by the other subassembly 12 b. This alternating operation of the

subassemblies

12a, 12b reduces their load and can be considered correspondingly cost-effectively in the structural design of the individual components of these

subassemblies

12a, 12 b.

Of course, it is also conceivable to control the brake system 10 in such a way that one of the subassemblies 12a controls all braking processes, while the respective other subassembly 12b is activated only in the event of a failure of this first subassembly 12 a.

During operation of the brake system 10 described, a further operating state can occur in which the inlet valve 26 is closed in one of the brake circuits 20a, since the required brake pressure is already reached in the associated wheel brake 30, which brake pressure must additionally be built up in the respective other brake circuit 20b, and therefore the inlet valve 26 of this brake circuit 20b is still open. In these cases, there are the following difficulties: since the pumps 16 are operated in common, in a brake circuit 20a, in which the required brake pressure has been reached, the circuit regions and the components arranged therein are exposed to undesirably high pressure loads.

A state can be reached in which the outlet valves 32 of the brake circuit 20a that have been adjusted are actuated in such a way that the pressure medium flows out of these outlet valves 32 in a throttled manner toward the reservoir 22, wherein the extent of the quantity of pressure medium flowing out is adjusted in such a way that the desired brake pressure is maintained without increased pressure loads occurring in the circuit region connected to the pressure side of the pump 16.

An alternative solution to this is shown in the embodiment according to fig. 2. In addition to the already described components, such a brake system 10' is equipped with a pump inlet valve 36, which is arranged on the inlet side of the pump 16 and thus controls the pressure medium connection of the pump 16 to the storage tank 22. The pump inlet valve 36 is designed as an 2/2-way switching valve with no flow opening and can be electronically actuated to block the pressure medium connection mentioned in the stated case in order to prevent an undesired pressure increase. The circuit diagram corresponds to that of fig. 1, except for the illustrated pump intake valve 36.

The exemplary embodiment according to fig. 3 shows a second alternative for solving the stated problem in the brake system 10 ″. This solution is a pressure limiting valve 38 for the control pressure, which is connected in parallel with the respective pump 16 of the

brake circuit

20a, 20 b. This pressure-limiting valve 38 is switched into a flow position, in which a connection of the pressure medium between the pressure side and the suction side of the pump 16 is present, i.e. a hydraulic short circuit is produced, as a function of the pressure on the pressure side of the pump 16 and counter to a restoring force. Due to this short circuit, the pump 16 only feeds pressure medium into the circuit, and thus prevents an undesired pressure increase in the circuit region between the outlet of the pump 16 and the inlet valve 26. Apart from the additional pressure limiting valve 38, the

brake circuits

20a, 20b are constructed in accordance with the brake circuit of fig. 1, wherein only one of the total two

brake circuits

20a, 20b of the brake system 10 is shown in fig. 2 and 3. In addition, mutually corresponding components have the same reference numerals in fig. 1 to 3.

In addition, the brake system 10 according to fig. 1 to 3 is also suitable for operating modes in which it is important to briefly displace a large amount of pressure medium to at least one of the wheel brakes 30 in order to brake or to stop the vehicle via a rapid brake pressure build-up on a short brake path. In such cases, those skilled in the art recognize particularly high pressure build-up dynamic braking conditions.

If such a need is determined, for example, by a vehicle-side sensor system, the two

subassemblies

12a, 12b are jointly actuated by the respectively associated electronic control unit 34 and are operated simultaneously. The two

subassemblies

12a, 12b thus supply pressure medium under brake pressure jointly or in parallel to a total of four wheel brakes 30 of the brake system 10. At the same time, the pressure build-up or inlet valves 26 of the

subassemblies

12a, 12b are actuated in such a way that a pressure medium-conducting connection is established between only one of the wheel brakes 30 and exactly one pump 16 of the brake system 10.

In contrast to the (normal) operating state, in which the brake circuit 20 a; 20b is connected to this brake circuit 20a under brake pressure; 20b, so that in the case of braking with high pressure build-up dynamics, only exactly one pump of the existing total of four pumps 16 is assigned to each wheel brake 30, or exactly one pump 16 supplies pressure medium to each wheel brake 30 at brake pressure.

The pump 16 and the associated wheel brake 30 are thus directly connected to one another, so that the enclosed pressure medium column between the components is very short and has a high rigidity. A correspondingly rapid and effective brake pressure build-up can take place in the wheel brakes 30.

The illustrated interconnection of the pressure build valve or inlet valve 26 is shown in fig. 4.

According to this fig. 4, the brake circuit 20a of the first subassembly 12a is equipped with a pump 16.1 and branches downstream of this pump 16.1 into a first brake branch 40.1 and a second brake branch 40.2. The two braking branches 40.1; 40.2 each contact a total of two wheel brakes 30.1 of the brake circuit 20 a; 30.2 and is equipped with a pressure build-up valve or inlet valve 26.1 at each wheel brake 30.1, 30.2, respectively; 26.2, which pressure build-up or inlet valve controls the pump 16.1 and the respectively associated wheel brake 30.1; 30.2 pressure medium connection.

The pressure build-up valve or inlet valve 26.1 of the first brake branch 40.1 is in an initial position in which the pressure medium connection between the pump 16.1 and the wheel brake 30.1 is open. In contrast, the inlet valve 26.2 is actuated by the electronic control unit 34.1 in the second brake branch 40.2 of the first brake circuit 20.1, assumes its blocking position and thus interrupts the pressure medium connection between the pump 16.1 and the second wheel brake 30.2. Therefore, the pump 16.1 of the first brake circuit 20a is now connected only to the two wheel brakes 30.1; 30.2 is connected to conduct the pressure medium.

The second wheel brake 30.2 is supplied with pressure medium via the second brake circuit 20 c. This second brake circuit 20c is formed in the second subassembly 12b which is arranged in parallel and, in addition to the further second pump 16.3, also comprises two brake branches 40.3 which branch downstream of this pump 16.3; 40.4 and the pressure build-up or inlet valve 26.3 arranged in the brake branches 40.3, 40.4; 26.4. one of these inlet valves 26.4 in turn assumes the flow position, while the other inlet valve 26.3 is switched into the blocking position by electronic actuation of the electronic control unit 34 b. The brake branch 40.4 of the second subassembly 12b with the inlet valve 26.4 in the flow position is connected to the second wheel brake 30.2, while the brake branch 40.3 with the closed inlet valve 26.3 is in contact with the first wheel brake 30.1. The second pump 16.3 therefore supplies pressure medium only to the second wheel brake 30.2 under brake pressure.

Since each of the two

subassemblies

12a, 12b has two

brake circuits

20a and 20b or 20c and 20d, respectively, corresponding to the illustrated embodiment, a total of four wheel brakes 30.1 to 30.4 of the brake system 10 can be acted upon individually in a simple manner by pressure medium under brake pressure via exactly one associated pump 16.1 to 16.4. A common drive motor 18 a; 18b are respectively sufficient to drive each sub-assembly 12a;12b, 16.1, 16.2 or 16.3, 16.4. The sub-assembly 12a; the brake circuits 20.b and 20.d of 12b, which are not explicitly illustrated, are configured identically to the illustrated

brake circuits

20a and 20c and supply the third wheel brake 30.3 or the fourth wheel brake 30.4 of the brake system 10 with pressure medium under brake pressure in an equivalent manner.

It is of course possible to divert the described actuation of the pressure buildup or inlet valves 26.1, 26.2 or 26.3, 26.4 and thus to connect the respective wheel brake 30.1, 30.2 pressure conduction medium to the respective other brake branch 40.1, 40.2 or 40.3, 40.4 of the

brake circuit

20a, 20 c. For the driving stability of the vehicle, it can be advantageous to assign the

different subassemblies

12a, 12b with wheel brakes 30.1 to 30.4 of different wheel axes, which are diagonally opposite to one another.

In addition thereto, changes or additions to the described embodiments can also be considered without deviating from the basic idea of the invention.

Claims

1. A braking device capable of being electronically regulated in voltage,

which is used for a motor vehicle running autonomously,

having a pressure medium assembly (12) for setting and regulating the brake pressure of individual wheels at wheel brakes (30) which are each associated with one of a plurality of brake circuits (20) of the brake system (10) and are connected to the pressure medium assembly (12),

wherein the pressure medium assembly (12) is equipped with an electronically controllable pump unit (16) at each brake circuit (20) and with an electronically controllable valve device (26, 32) at each connected wheel brake (30), which valve device controls the inflow of pressure medium to the wheel brake (30),

it is characterized in that the preparation method is characterized in that,

each wheel brake (30) of the brake system (10) is in contact with at least one second brake circuit (20) which is equipped with an electronically controllable second pump unit (16) and with an electronically controllable second valve device (26, 32) at each connected wheel brake (30), wherein the pump unit (16) and the valve device (26, 32) of one brake circuit (20) can be operated independently of the pump unit (16) and the valve device (26, 32) of the respective other brake circuit (20), wherein the brake system has no main brake cylinder or brake pedal, and the pump inlets of the pumps used are each directly connected to a pressure medium reservoir.

2. The electronically voltage adjustable brake apparatus of claim 1,

it is characterized in that the preparation method is characterized in that,

the valve devices (26, 32) associated with the wheel brakes (30) are each divided into an inlet valve (26) which controls the inflow of pressure medium to the wheel brakes (30) and an outlet valve (32) which controls the outflow of pressure medium from the wheel brakes (30), wherein the outlet valve (32) can be switched from a closed position into an unlimited number of intermediate positions into a flow position as a function of an electronic actuation.

3. The electronically voltage adjustable brake apparatus of claim 2,

it is characterized in that the preparation method is characterized in that,

downstream of the valve devices (26) there are in each case one non-return valves (28) which are open in the flow direction from the valve devices (26; 32) to the wheel brakes (30) and are blocked in the flow direction opposite thereto.

4. The electronically voltage adjustable brake apparatus of claim 3,

it is characterized in that the preparation method is characterized in that,

at least two brake circuits (20) associated with wheel brakes (30) are in pressure-conducting contact with one another, wherein the brake circuits (20) are in contact downstream of the non-return valves (28).

5. The electronically voltage adjustable brake apparatus of any one of claims 2 to 4,

it is characterized in that the preparation method is characterized in that,

the outlet valves (32) are each arranged in a return structure (24) which is connected directly to the intake connection of the pump unit (16) and in parallel to a storage tank (22) connected to the pressure medium assembly (12).

6. The electronically voltage adjustable brake apparatus of any one of claims 1 to 4,

it is characterized in that the preparation method is characterized in that,

the first pump unit (16) of the first brake circuit (20) of the first subassembly (12 a) and the first pump unit (16) of the second brake circuit (20) are arranged in a common first pump housing (14) having a first drive motor (18) for actuating the pump unit (16), and,

the second pump unit (16) of the first brake circuit (20) of the second subassembly (12 b) and the second pump unit (16) of the second brake circuit (20) are arranged in a common second pump housing (14) which is structurally separate from the first pump housing (14) and has a second drive motor (18) for actuating the pump unit (16).

7. The electronically voltage adjustable brake device of claim 6,

it is characterized in that the preparation method is characterized in that,

only interfaces for the wheel brakes (30) arranged on the outside and for a storage container (22) are formed on each of the pump housings (14).

8. The electronically voltage adjustable brake apparatus of any one of claims 1 to 4,

it is characterized in that the preparation method is characterized in that,

an electronically controllable pump inlet valve (36) for controlling the pressure medium supply of at least one pump unit (16) of the brake circuit (20) is provided on the inlet side of this pump unit (16).

9. The electronically voltage adjustable brake apparatus of any one of claims 1 to 4,

it is characterized in that the preparation method is characterized in that,

a pressure-limiting valve (38) is connected in parallel with at least one pump unit (16) of the brake circuit (20), said valve controlling the pressure medium connection from the pressure side to the suction side of this pump unit (16) as a function of the pressure on the pressure side of the same pump unit (16).

10. Method for controlling an electronically pressure-adjustable brake system, in which each connected wheel brake (30) is in contact with at least two mutually separate brake circuits (20) which are each equipped with a pump unit (16) and a valve device (26; 32) for adjusting the brake pressure in the wheel brake (30), wherein the pump unit (16) and the valve devices (26; 32) can each be actuated independently of one another and separately from one another, characterized in that,

the brake pressure is controlled alternately during successive braking operations by actuating the pump unit (16) and the valve device (26; 32) of one brake circuit (20) or by actuating the pump unit (16) and the valve device (26; 32) of the respective other brake circuit (20),

in this case, the brake system does not have a master cylinder or a brake pedal, and the pump inlets of the pumps used are each connected directly to a pressure medium reservoir.

11. Method for controlling an electronically pressure-adjustable brake system, in which each connected wheel brake (30) is in contact with at least two mutually separate brake circuits (20) which are each equipped with a pump unit (16) and a valve device (26; 32) for adjusting the brake pressure in the wheel brake (30), wherein the pump unit (16) and the valve devices (26; 32) can each be actuated independently of one another and separately from one another, characterized in that,

the brake pressure is controlled by actuating a pump unit (16) and a valve device (26; 32) of a brake circuit (20) during successive braking operations, and,

when an operational failure of one brake circuit (20) is determined, the pump unit (16) and the valve device (26; 32) of the respective other brake circuit (20) are actuated,

12. Method for controlling an electronically pressure-adjustable brake system, in which each connected wheel brake (30) is in contact with at least two mutually separate brake circuits (20) which are each equipped with a pump unit (16) and a valve device (26; 32) for adjusting the brake pressure in the wheel brake (30), wherein the pump unit (16) and the valve devices (26; 32) can each be actuated independently of one another and separately from one another, characterized in that,

simultaneously actuating the pump units (16) of the brake circuits (20) and actuating the valve devices (26, 32) of the brake circuits (20) in such a way that a pressure medium-conducting connection is produced between in each case one of the wheel brakes (30) and exactly one pump of the pump units (16),

13. The method of claim 12,

the method is performed when there is a braking situation with high pressure build-up dynamics.

14. The method of claim 13,

the valve arrangement (26, 32) of the brake circuit (20) has a first and a second inlet valve (26) which are each assigned to a wheel brake (30) of the brake circuit (20), and, in the event of dynamic braking with high pressure build-up, the inlet valves (26) are actuated such that one of the inlet valves (26) of the brake circuit (20) assumes a flow position and the respective other inlet valve (26) of the same brake circuit (20) assumes a blocking position.