CONTROL DEVICE AND METHOD FOR ACTIVATING A VEHICLE POWER BRAKE SYSTEM - Patent application

Abstract

The present invention relates to a control system (10) for a vehicle power braking system. The control device can activate a motor (M) of an electric piston cylinder device (20) and can switch at least one first valve (22a) and at least one second valve (22b). First wheel brake cylinders (12a, 12b) are hydraulically coupled to at least one fluid receiving volume (20c, 20d) of the electric piston cylinder device (20) via at least the at least one first valve (22a) and second wheel brake cylinders (14a, 14b) are hydraulically coupled to at least one fluid receiving volume (20c, 20d) of the electric piston cylinder device (20) via at least the at least one second valve (22b). In this case, in order to simultaneously perform the brake pressure maintaining function or the brake pressure increasing function for the first wheel brake cylinder (12a, 12b) and the brake pressure reducing function for the second wheel brake cylinder (14a, 14b), while the transfer of brake fluid from the first wheel brake cylinder (12a, 12b) into the at least one enlarged liquid receiving area (20c, 20d) is prevented by the at least one first valve (22a) switched to closed, brake fluid can be sucked from the second wheel brake cylinder (14a, 14b) into the at least one enlarged liquid receiving area (20c, 20d) through the at least one second valve (22b) switched to at least partially open.

Description

[Technical Field]

[0001] The present invention relates to a control device for a power brake system of a vehicle. The present invention also relates to a power brake system for a vehicle. The present invention also relates to a method of operating a power brake system of a vehicle. [Background technology]

[0002] The prior art, for example, from US Pat. No. 5,699,999, discloses a conventional method for suppressing a generator brake torque generated on a vehicle by at least one electric motor operated in recovery mode. This method makes it possible to prevent or at least limit the brake pressure buildup in at least one wheel brake cylinder of the vehicle's hydraulic brake system. For this purpose, at least one wheel exhaust valve arranged downstream of the respective wheel brake cylinder is at least temporarily switched to its open state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] German Patent Application Publication No. 102018212269 Summary of the Invention

[0004] The present invention provides a control device for a power brake system of a vehicle having the features of claim 1, a power brake system for a vehicle having the features of claim 4, and a method for operating a power brake system of a vehicle having the features of claim 8.

[0005] The present invention provides a quieter means for overriding the generator braking torque applied to a respective vehicle by at least one electric motor of the vehicle being used as a generator. Advantageously, the present invention utilizes an electric piston-cylinder device already frequently used in power brake systems to overriding the generator braking torque, so that implementation of the present invention does not require hardware expansion in the respective power brake system. Rather, reprogramming of the respective power brake system controller is typically sufficient to implement the present invention. This facilitates use of the present invention on many different types of vehicles.

[0006] A further advantage of the present invention is that when the power brake system includes an electric piston cylinder device, the driver of a vehicle equipped with a power brake system (typically) does not intervene in braking by operating the power brake system. Therefore, a driver who instead intervenes in braking by operating the driver's brake operating element / brake pedal in the simulator will not be confused by the simultaneous use of the electric piston cylinder device of the power brake system to produce a brake decompression function. Therefore, the present invention not only allows for less masking of generator brake torque noise, but also provides the driver with a standard brake operation / pedal feel.

[0007] In an advantageous embodiment of the control device, the electronic mechanism is additionally designed and / or programmed in such a way that, in order to simultaneously perform a brake pressure increase function for a first wheel brake cylinder and a brake pressure decrease function for a second wheel brake cylinder, while the transfer of brake fluid from the first wheel brake cylinder into the at least one fluid receiving volume expanded by the activated motor is prevented by the at least one first valve switched to closed and while brake fluid can be sucked from the second wheel brake cylinder into the at least one expanded fluid receiving volume via the at least one second valve switched to at least partially open, the electronic mechanism can simultaneously additionally activate a pump motor of at least one pump of the power brake system so that brake fluid can be delivered into the first wheel brake cylinder by the at least one activated pump. Therefore, the described embodiment of the control device takes advantage of the fact that if a power brake system has an electric piston cylinder device and at least one pump as its two actuators, the operation of the at least one pump is not / almost impeded by closing the at least one first valve, so that the electric piston cylinder device can be used to reduce brake pressure in the second wheel brake cylinder and at the same time the at least one pump can be used to increase brake pressure in the first wheel brake cylinder.

[0008] In a further advantageous embodiment of the control device, the electronics are additionally designed and / or programmed so that, in order to simultaneously perform a first brake pressure reduction function for a first wheel brake cylinder with a first target gradient and a second brake pressure reduction function for a second wheel brake cylinder with a second target gradient higher than the first target gradient, during the transfer of brake fluid from the second wheel brake cylinder to the at least one fluid receiving volume expanded by the activated motor via the at least one second valve switched at least partially open, the transfer of brake fluid from the first wheel brake cylinder to the at least one expanded fluid receiving volume is interrupted multiple times by the at least one first valve switched closed for short periods of time, which also allows for relatively quiet concealment of the generator brake torque of at least one electric motor of the vehicle used as a generator.

[0009] The above-mentioned advantages are also ensured in a power brake system for a vehicle, comprising a corresponding control device, an electric piston cylinder device, the motor of which can be activated by an electronic mechanism of the control device so as to variably activate at least one liquid receiver volume of the electric piston cylinder device, two first wheel brake cylinders which can be arranged or disposed on a first axle of the vehicle and two second wheel brake cylinders which can be arranged or disposed on a second axle of the vehicle, and first and second valves which can be switched by the electronic mechanism, the first wheel brake cylinder and the second wheel brake cylinder being hydraulically coupled to the at least one liquid receiver volume via at least the at least one first valve and at least the at least one second valve, respectively.

[0010] In a first advantageous embodiment of the power brake system, the first wheel brake cylinder is hydraulically coupled to a first brake circuit of the power brake system, and the second wheel brake cylinder is hydraulically coupled to a second brake circuit of the power brake system, in which the only first valve is a selector valve for the first brake circuit, and the only second valve is a selector valve for the second brake circuit. The selector valves can be switched more quietly than the wheel exhaust valves of such a power brake system. Therefore, the power brake system described herein allows for particularly quiet concealment of the generator-brake torque applied to the vehicle by means of at least one electric motor used as a generator.

[0011] In a second advantageous embodiment of the power brake system, one first wheel brake cylinder of the first plurality of first wheel brake cylinders and one second wheel brake cylinder of the second plurality of second wheel brake cylinders are hydraulically connected to a first brake circuit of the power brake system, and another first wheel brake cylinder of the first plurality of first wheel brake cylinders and another second wheel brake cylinder of the second plurality of second wheel brake cylinders are hydraulically connected to a second brake circuit of the power brake system, the two first valves being a wheel suction valve supported upstream of the first wheel brake cylinder of the first brake circuit and a wheel suction valve supported upstream of the first wheel brake cylinder of the second brake circuit, and the two second valves being a wheel suction valve supported upstream of the second wheel brake cylinder of the first brake circuit and a wheel suction valve supported upstream of the second wheel brake cylinder of the second brake circuit. The aforementioned advantages can therefore also be utilized for power brake systems with X-compartment brake circuits.

[0012] In an advantageous embodiment, the electric piston cylinder device is a DPB device, which should be understood as a "Decoupled Power Brake" device. As will become clear from the following description, the driver operating the brake operating element / brake pedal does not feel any reaction when actually using the DPB device to override the generator brake torques for each axle that are simultaneously generated by at least one electric motor of the vehicle to slow down the respective vehicle.

[0013] The above-mentioned advantages also arise by implementing a corresponding method for operating a power braking system of a vehicle, which method can be further developed according to the above-mentioned embodiments of the control device and / or the power braking system.

[0014] Further features and advantages of the present invention will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of a first embodiment of a control system for or associated with a power brake system; [Figure 2] 1 is a schematic diagram of a second embodiment of a control system for or associated with a power brake system; [Figure 3] 1 is a flow chart illustrating one embodiment of a method for operating a power braking system of a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0016] FIG. 1 is a schematic diagram of a first embodiment of a control system for or associated with a power braking system.

[0017] 1 or the power braking system associated therewith is not limited to any particular type of vehicle / automobile. Instead, the control device 10 and power braking system may be installed on (almost) any vehicle / automobile having two first wheels mounted on a first axle of the vehicle / automobile and two second wheels located on a second axle of the vehicle / automobile. A vehicle equipped with a power braking system may be, for example, a passenger car, a truck, or an off-highway vehicle.

[0018] The power brake system of Figure 1 has two first wheel brake cylinders 12a and 12b and two second wheel brake cylinders 14a and 14b, where a first wheel of the vehicle can be braked using the first wheel brake cylinders 12a and 12b and a second wheel of the vehicle can be braked using the second wheel brake cylinders 14a and 14b. For the same or different brake pressures in the first wheel brake cylinders 12a and 12b, a maximum value can be defined as a first maximum brake pressure and a minimum value can be defined as a first minimum brake pressure. Correspondingly, for the same or different brake pressures in the second wheel brake cylinders 14a and 14b, the maximum value can be referred to as a second maximum brake pressure and the minimum value can be referred to as a second minimum brake pressure. The power brake system of FIG. 1 has a II-compartment brake circuit (parallel-compartment brake circuit), i.e., the first wheel brake cylinders 12a and 12b are hydraulically coupled to a first brake circuit 16 of the power brake system, and the second wheel brake cylinders 14a and 14b are hydraulically coupled to a second brake circuit 18 of the power brake system.

[0019] The controller 10 associated with the power brake system may be at least one component of the power brake system or at least one unit that can be / is separately attached to the power brake system. Although the controller 10 is illustrated in FIG. 1 as an integrated control unit, the configurability of the controller 10 is not limited in this respect. Thus, the functions performed by the controller 10 / its electronics 10a may be performed by multiple units that are separate from one another.

[0020] The electronic mechanism 10a of the control device 10 is designed and / or programmed so that the motor M, at least one first valve 22a, and at least one second valve 22b of the electric piston cylinder device 20 of the power brake system are actuable / activated by the electronic mechanism 10a. The motor M of the electric piston cylinder device 20 is actuable / activated using at least one motor control signal 10b output from the electronic mechanism 10a so that the at least one linearly displaceable piston 20a, 20b of the electric piston cylinder device 20 is displaceable / displaced using the actuated motor M, so that at least one liquid receiving volume 20c, 20d of the electric piston cylinder device 20 defined by the at least one piston 20a, 20b is changeable / changeable (in terms of its size). The electric piston cylinder device 20 may be, for example, a DPB device (Decoupled Power Brake). In particular, the first brake circuit 16 of the power brake system may be hydraulically coupled to the first fluid receiver volume 20c, and the second brake circuit 18 of the power brake system may be hydraulically coupled to the second fluid receiver volume 20d of the motorized piston cylinder device 20.

[0021] The first and second valves 22a and 22b, switchable by the electronic mechanism 10a, are arranged in the power brake system such that the first wheel brake cylinders 12a and 12b are hydraulically coupled to at least one fluid receiving volume 20c and 20d via at least one first valve 22a and the second wheel brake cylinders 14a and 14b are hydraulically coupled to at least one fluid receiving volume 20c and 20d via at least one second valve 22b. The at least one first valve 22a can be switched by at least one first valve switching signal 10c output from the electronic mechanism 10a. Correspondingly, the at least one second valve 22b is switched by at least one second valve switching signal 10d output from the electronic mechanism 10a. Advantageous embodiments of the first and second valves 22a and 22b will be described further below.

[0022] Furthermore, the electronic mechanism 10a is designed and / or programmed such that, using the electronic mechanism 10a, a brake pressure holding function or a brake pressure increase function for the first wheel brake cylinders 12a, 12b and a brake pressure decrease function for the second wheel brake cylinders 14a, 14b can be simultaneously performed. In order to simultaneously perform a brake pressure holding function or a brake pressure increase function for the first wheel brake cylinders 12a, 12b and a brake pressure decrease function for the second wheel brake cylinders 14a, 14b, the motor M of the electric piston cylinder device 20 can be activated using the electronic mechanism 10a such that at least one fluid receiving volume 20c, 20d of the electric piston cylinder device 20 is / is enlarged by displacing its at least one piston 20a, 20b using the activated motor M. At the same time, while the transfer of brake fluid from the first wheel brake cylinders 12a, 12b into the at least one enlarged fluid receiver volume 20c, 20d is prevented by the at least one first valve 22a switched to closed, the electronic mechanism 10a can / is able to draw brake fluid from the second wheel brake cylinders 14a, 14b into the at least one enlarged fluid receiver volume 20c, 20d through the at least one second valve 22b switched to at least partially open. In other words, while the same or different brake pressures are trapped in the first wheel brake cylinders 12a, 12b by closing the at least one first valve 22a, the electronic mechanism 10a can / is able to reduce the same or different brake pressures in the second wheel brake cylinders 14a, 14b by drawing brake fluid into the at least one fluid receiver volume 20c, 20d.

[0023] The braking action of the second wheel brake cylinders 14a and 14b, which is lost due to the resulting brake pressure reduction, can be used to override the generator brake torque applied by at least one electric motor (not shown) of the vehicle operated in recovery mode. Therefore, using the at least one electric motor as a generator, kinetic energy can be converted into electrically storable energy during vehicle braking / deceleration without exceeding the target vehicle deceleration requested by the driver or the vehicle's automation system. The advantageous design / programming of the electronics 10a thus enables axle-by-axle override, which can be achieved via at least one wheel bleed valve 24a and 24b of the power brake system without displacing brake fluid. Therefore, the first and second valves 22a and 22b can take advantage of the fact that they can be switched more quietly than the (usually) wheel bleed valves 24a and 24b of the power brake system. In particular, while simultaneously performing a brake pressure maintaining or increasing function for the first wheel brake cylinders 12 a, 12 b and a brake pressure reducing function for the second wheel brake cylinders 14 a, 14 b, at least one first wheel exhaust valve 24 a arranged downstream of the first wheel brake cylinders 12 a, 12 b and at least one second wheel exhaust valve 24 b arranged downstream of the second wheel brake cylinders 14 a, 14 b can be controlled / held closed. Therefore, axle-specific concealment that can be generated using the design / programming of the electronic system 10 a is relatively quiet.

[0024] A further advantage of the design / programming of the electronics 10a of the control device 10 is the use of the electric piston cylinder device 20 to generate brake pressure reduction in the second wheel brake cylinders 14a and 14b. In the case of a power brake system, particularly in its "full function mode," the vehicle driver is decoupled from the power brake system so that the driver operating the brake operating element / brake pedal (not shown) does not directly interfere with the power brake system's hydraulic system. Instead, the driver performs braking via a simulator (not shown) during the power brake system's "full function mode." Therefore, the driver operating the brake operating element / brake pedal does not feel any adverse effect from the use of the electric piston cylinder device 20 to reduce the brake pressure in the second wheel brake cylinders 14a and 14b. A power brake system may be understood, particularly, as a driver-decoupled brake system or a by-wire brake system.

[0025] 1, the first switching valve 22a is used as the sole first valve 22a, and the second switching valve 22b is used as the sole second valve 22b. Therefore, with advantageous design / programming of the electronic mechanism 10a, it can be taken advantage of that the switching valves 22a and 22b can be switched relatively quietly, particularly more quietly than the wheel exhaust valves 24a and 24b.

[0026] Therefore, the electronic system 10a is designed and / or programmed so that if the second maximum brake pressure in the second wheel brake cylinders 14a, 14b is less than or equal to the first minimum brake pressure in the first wheel brake cylinders 12a, 12b, the electronic system 10a can / will simultaneously perform the brake pressure maintenance or pressure increase function for the first wheel brake cylinders 12a, 12b and the brake pressure decrease function for the second wheel brake cylinders 14a, 14b in the manner described above, precisely at that moment, by using the electronic system 10a, taking advantage of the fact that the check valve 22c of the first switching valve 22a, which has been switched closed, is open only if / when the second maximum brake pressure is / will be greater than the first minimum brake pressure. (The check valve 22c of the first switching valve 22a is oriented as follows: it is oriented so that the transfer of brake fluid from the first wheel brake cylinders 12a and 12b through the check valve 22c of the first switching valve 22a to the electric piston cylinder device 20 is prevented.) Thus, the configuration / programming of the electronic mechanism 10a described herein makes it possible to utilize the first switching valve 22a as a gate valve, even though it is equipped with a check valve 22c.

[0027] In an advantageous further configuration, the control device 10 / its electronics 10a can additionally be designed and / or programmed such that a brake pressure increase function for the first wheel brake cylinders 12a, 12b and a brake pressure decrease function for the second wheel brake cylinders 14a, 14b can be simultaneously performed by means of the electronics 10a. To achieve this, while the transfer of brake fluid from the first wheel brake cylinders 12a, 12b into the at least one fluid receiving volume 20c, 20d expanded by the activated motor M is blocked by means of the at least one first valve 22a switched to closed, and while at the same time brake fluid can be / is being drawn from the second wheel brake cylinders 14a, 14b into the at least one expanded fluid receiving volume 20c, 20d via the at least one second valve 22b switched to at least partially open, the pump motor M of at least one pump 26a, 26b of the power brake system can also be driven. P can be activated by the electronics 10a to pump / cause brake fluid to be delivered into the first wheel brake cylinders 12a, 12b by means of the activated at least one pump 26a. In particular, the electronics 10a can be configured / programmed to be able to / to perform a brake pressure increase function for the first wheel brake cylinders 12a, 12b and a brake pressure decrease function for the second wheel brake cylinders 14a, 14b together if and at the exact moment the second maximum brake pressure in the second wheel brake cylinders 14a, 14b is less than or equal to the first minimum brake pressure in the first wheel brake cylinders 12a, 12b.

[0028] Thus, the advantageous design / programming of the electronics 10a described in the previous paragraph makes it possible to take advantage of the fact that power brake systems often have not only an electric piston cylinder arrangement 20 as its first actuator, but also at least one pump 26a, 26b as its second actuator, in order to ensure excellent redundancy. Furthermore, the design / programming of the electronics 10a can be used to take advantage of the fact that the first wheel brake cylinders 12a, 12b, together with their associated pumps 26a, are isolated from the electric piston cylinder arrangement 20 and the second wheel brake cylinders 14a, 14b by means of at least one first valve 22a, which is switched closed. The brake fluid delivered by the at least one activated pump 26a into the first wheel brake cylinders 12a, 12b while the at least one first valve 22a is closed / held closed can be / is sucked in via the first high-pressure switching valve 28a of the first brake circuit 16, which is switched to be at least partially open. By closing / holding closed the second high-pressure switching valve 28b of the second brake circuit 18, the pump motor M P An undesired pressure buildup in the second wheel brake cylinders 14a and 14b due to simultaneous actuation of the pump 26b of the second brake circuit 18 by the brake fluid is (substantially) prevented / can be prevented.

[0029] Instead of simultaneously implementing the above-mentioned brake pressure increase function for the first wheel brake cylinders 12a, 12b and brake pressure decrease function for the second wheel brake cylinders 14a, 14b, the brake force distribution between the four wheel brake cylinders 12a, 12b, 14a, 14b can also be varied by combining a slow brake decrease in the second wheel brake cylinders 14a, 14b with a brake pressure hold in the first wheel brake cylinders 12a, 12b.

[0030] As a further optional refinement, the electronics 10a of the control device 10 may be designed and / or programmed in such a way that the electronics 10a can / will simultaneously perform a first brake pressure reduction function with a first target gradient for the first wheel brake cylinders 12a and 12b and a second brake pressure reduction function with a second target gradient for the second wheel brake cylinders 14a and 14b, the second target gradient being above the first target gradient. This can also be achieved in the following way: while the brake fluid is being transferred from the second wheel brake cylinders 14a and 14b through at least one second valve 22b switched to be at least partially open into at least one liquid receiving volume 20c and 20d enlarged by the activated motor M, the transfer of brake fluid from the first wheel brake cylinders 12a and 12b into at least one enlarged liquid receiving volume 20c and 20d is / is interrupted multiple times using at least one first valve 22a switched to be closed for short periods of time. Preferably, the electronic mechanism 10a is configured / programmed such that it is capable / programmed to simultaneously perform a first brake pressure reduction function with a first target gradient for the first wheel brake cylinders 12a, 12b and a second brake pressure reduction function with a second target gradient for the second wheel brake cylinders 14a, 14b if and only if the second maximum brake pressure in the second wheel brake cylinders 14a, 14b is less than or equal to the first minimum brake pressure in the first wheel brake cylinders 12a, 12b.

[0031] Alternatively or additionally, the electronic system 10a can be used to simultaneously activate a first brake pressure reduction function with a first target gradient for the second wheel brake cylinders 14a, 14b and a second brake pressure reduction function with a second target gradient for the first wheel brake cylinders 12a, 12b in such a way that, while the brake fluid is being transferred from the first wheel brake cylinders 12a, 12b via the at least one first valve 22a, which is switched at least partially open, into the at least one fluid receiver volume 20c, 20d enlarged by the activated motor M, the transfer of brake fluid from the second wheel brake cylinders 14a, 14b to the at least one enlarged fluid receiver volume 20c, 20d is interrupted / interrupted several times by the at least one second valve 22b, which is switched to closed for short periods of time. Advantageously, this also allows for the concealment of non-zero generator brake torques axle-by-axle.

[0032] The electronic system 10a can selectively activate / can activate a first brake pressure boosting function with a first target gradient for the first wheel brake cylinders 12a, 12b and a second brake pressure boosting function with a second target gradient for the second wheel brake cylinders 14a, 14b, where the first target gradient is above the second target gradient. For this purpose, while the brake fluid is transferred from the at least one fluid receiver volume 20c, 20d reduced by the activated motor M into the first wheel brake cylinders 12a, 12b via the at least one first valve 22a switched at least partially open, the transfer of brake fluid from the at least one reduced fluid receiver volume 20c, 20d into the second wheel brake cylinders 14a, 14b can be interrupted / can be interrupted several times by the at least one second valve 22b switched closed for short periods of time. Alternatively, during the transfer of brake fluid from the at least one reduced liquid receiving volume 20c, 20d to the first wheel brake cylinders 12a, 12b via the at least one first valve 22a switched to be at least partially open and the at least one first wheel intake valve 30a arranged upstream of the first wheel brake cylinders 14a, 14b switched to be at least partially open, the transfer of brake fluid from the at least one reduced liquid receiving volume 20c, 20d into the second wheel brake cylinders 14a, 14b may be interrupted / halted multiple times by the at least one second wheel intake valve 30b arranged upstream of the second wheel brake cylinders 14a, 14b switched to be closed for short periods of time. Correspondingly, the electronic mechanism 10a may be / may be used to simultaneously generate a first brake pressure boost function with a first target gradient for the second wheel brake cylinders 14a and 14b and a second brake pressure boost function with a second target gradient for the first wheel brake cylinders 12a and 12b.

[0033] In all of the above, the brake pressure can be adjusted in the wheel brake cylinders 12a, 12b, 14a, 14b using an electronic mechanism 10a such that the target vehicle deceleration requested by the driver or the vehicle's automation system is equal to the total brake torque M acting on the vehicle. total In this case, the total brake torque M total is the first hydraulic partial brake torque M generated by the first wheel brake cylinders 12a and 12b on the first axle of the vehicle. h1 and a second hydraulic partial brake torque M generated by the second wheel brake cylinders 14a and 14b on the second axle of the vehicle. h2 and a partial braking torque M generated by a first generator on a first axle of the vehicle by means of at least one electric motor operated in a recovery mode. m1 and a partial braking torque M generated by a second generator on a second axle of the vehicle by means of at least one electric motor operated in a recovery mode. m2 In order to compensate for any leakage via the at least one wheel inlet valve 30a, 30b arranged upstream, the at least one wheel outlet valve 24a, 24b arranged downstream, respectively, can be at least partially opened after a target pressure of (approximately) 0 bar has been reached or after a target pressure of atmospheric pressure in the first wheel brake cylinders 12a, 12b and / or atmospheric pressure in the second wheel brake cylinders 14a, 14b has been reached.

[0034] The power brake system of FIG. 1 is configured as a two-box system, but this is by way of example only. A first box 32a of the two-box system includes the motorized piston-cylinder device 20 and a brake fluid reservoir 34 hydraulically coupled thereto. A second box 32b of the two-box system includes the valves 22a, 22b, 24a, 24b, 28a, 28b, 30a, 30b, at least one pump 26a, 26b, a storage chamber 36 disposed downstream of the wheel bleed valve 24a or 24b for each of the brake circuits 16 and 18, a check valve 38 disposed between the storage chamber 36 and the respective pump 26a or 26b, and a front pressure sensor 40 coupled to the second brake circuit 18. However, the power brake system components illustrated in FIG. 1 should be construed as being by way of example only.

[0035] The same or different brake pressures in the first wheel brake cylinders 12a, 12b and the same or different brake pressures in the second wheel brake cylinders 14a, 14b, or the first maximum brake pressure, the first minimum brake pressure, the second maximum brake pressure, and / or the second minimum brake pressure, may be physical quantities assessed by the electronics 10a. Alternatively or additionally, the electronics 10a may be designed / programmed to read out the same or different brake pressures in the first wheel brake cylinders 12a, 12b and the same or different brake pressures in the second wheel brake cylinders 14a, 14b, or the first maximum brake pressure, the first minimum brake pressure, the second maximum brake pressure, and / or the second minimum brake pressure, from at least one sensor signal, in particular from at least one sensor, such as a front pressure sensor 40, coupled to the second brake circuit 18.

[0036] FIG. 2 is a schematic diagram of a second embodiment of a control system for or associated with a power braking system.

[0037] The power brake system shown schematically in Figure 2 differs from the previously described embodiment of Figure 1 in that one of the first wheel brake cylinders 12a and one of the second wheel brake cylinders 14a are connected to the first brake circuit 16, while the other of the first wheel brake cylinders 12b and one of the second wheel brake cylinders 14b are associated with the second brake circuit 18. The power brake system of Figure 2 is therefore configured with an X-compartment brake circuit.

[0038] 2 is also designed and / or programmed so that the electronics 10a can simultaneously perform a brake pressure maintaining or increasing function for the first wheel brake cylinders 12a, 12b and a brake pressure reducing function for the second wheel brake cylinders 14a, 14b. To achieve this, while the transfer of brake fluid from the first wheel brake cylinders 12a, 12b into the at least one enlarged fluid receiving volume 20c, 20d is prevented by the at least one first valve 30a being switched closed, the electronics 10a allows / is able to draw brake fluid from the second wheel brake cylinders 14a, 14b into the at least one enlarged fluid receiving volume 20c, 20d via the at least one second valve 30b being switched at least partially open. 2, the two first valves 30a are a wheel intake valve 30a arranged upstream of the first wheel brake cylinder 12a in the first brake circuit 16 and a wheel intake valve 30a arranged upstream of the first wheel brake cylinder 12b in the second brake circuit 18. Correspondingly, the two second valves 30b are a wheel intake valve 30b arranged upstream of the second wheel brake cylinder 14a in the first brake circuit 16 and a wheel intake valve 30b arranged upstream of the second wheel brake cylinder 14b in the second brake circuit 18. In this case, the electronics 10a utilizes the fact that the respective check valve 30c of the wheel intake valve 30a used as the first valve 30a is only opened if the second minimum brake pressure is lower than the first maximum brake pressure. (Each check valve 30c is oriented so as to prevent transfer of brake fluid from the motorized piston-cylinder device 20 through the check valve 30c to the downstream first wheel brake cylinder 12a or 12b.)

[0039] Therefore, the electronic system 10a is preferably designed and / or programmed so that, if the second minimum brake pressure in the second wheel brake cylinders 14a, 14b is greater than or equal to the first maximum brake pressure in the first wheel brake cylinders 12a, 12b, the electronic system 10a can / will simultaneously perform the brake pressure maintenance or pressure increase function for the first wheel brake cylinders 12a, 12b and the brake pressure decrease function for the second wheel brake cylinders 14a, 14b in the manner described above, at that very moment. The described configuration / programming of the electronic system 10a therefore makes it possible to use the wheel intake valves 30a arranged upstream of the first wheel brake cylinders 12a, 12b as gate valves, even though these wheel intake valves are each equipped with a check valve 30c.

[0040] Similarly, the electronic mechanism 10a may be capable of activating simultaneously a first brake pressure reduction function with a first target gradient for the first wheel brake cylinders 12a, 12b and a second brake pressure reduction function with a second target gradient for the second wheel brake cylinders 14a, 14b, the second target gradient being above the first target gradient. For this purpose, while the brake fluid is being transferred from the second wheel brake cylinders 14a, 14b into the at least one enlarged fluid receiver volume 20c, 20d via the at least one second valve 30b switched at least partially open, the transfer of brake fluid from the first wheel brake cylinders 12a, 12b to the at least one enlarged fluid receiver volume 20c, 20d may be interrupted multiple times by the at least one first valve 30a switched closed for short periods of time.

[0041] Other steps described with reference to the above embodiment may also be implemented using corresponding configuration / programming of the electronics 10a. Thus, the advantageous cooperation of the control device 10 with the power brake system of Figure 2 allows for many quiet means of masking the generator brake torque applied by at least one electric motor (not shown) of the vehicle operated in recovery mode.

[0042] For further characteristics and features of the power braking system of FIG. 2 and their advantages, please refer to the previously described embodiment of FIG. 1.

[0043] FIG. 3 is a flow chart illustrating one embodiment of a method for operating a power braking system of a vehicle.

[0044] The following description may be implemented using, for example, the power brake system described above. However, the applicability of the method is not limited to this type of power brake system. Similarly, the applicability of the method is not limited to a particular type of vehicle / automobile.

[0045] The method includes at least method steps S1 to S3, which are performed simultaneously to simultaneously perform a brake pressure maintaining function or a brake pressure increasing function for two first wheel brake cylinders of a power brake system arranged on a first axle of the vehicle and a brake pressure decreasing function for two second wheel brake cylinders of the power brake system arranged on a second axle of the vehicle. In method step S1, a motor of an electric piston cylinder device of the power brake system is activated so that at least one fluid receiver volume of the electric piston cylinder device is enlarged using the activated motor. Simultaneously, in method step S2, at least one first valve of the power brake system is switched so that, while the first wheel brake cylinder is hydraulically coupled to at least one fluid receiver volume via the at least one first valve, the at least one first valve switched to closed prevents transfer of brake fluid from the first wheel brake cylinder into the at least one fluid receiver volume enlarged using the activated motor. Likewise, in method step S3, which is performed simultaneously, at least one second valve of the power brake system is switched so that brake fluid is drawn from the second wheel brake cylinder into the at least one enlarged liquid receiving volume via the at least one second valve, which has been switched at least partially open, while the second wheel brake cylinder is hydraulically connected to the at least one liquid receiving volume via the at least one second valve. Embodiments for the at least one first valve and the at least one second valve, as well as preferred conditions for performing method steps S1 to S3, have already been described above.

[0046] Optionally, when carrying out the method described herein, a brake pressure increase function for a first wheel brake cylinder and a brake pressure decrease function for a second wheel brake cylinder can be simultaneously performed by performing method steps S1 to S3 as well as method step S4, in which, while the transfer of brake fluid from the first wheel brake cylinder into the at least one fluid receiving volume enlarged by the activated motor is prevented by the at least one first valve switched to closed and brake fluid is sucked from the second wheel brake cylinder into the at least one enlarged fluid receiving volume via the at least one second valve switched to at least partially open (method steps S3 to S3), a pump motor of at least one pump of the power brake system is additionally activated so that brake fluid is delivered into the first wheel brake cylinder by the at least one activated pump.

[0047] Similarly, when carrying out the method described herein, it is also possible to simultaneously generate a first brake pressure reduction function with a first target gradient for a first wheel brake cylinder and a second brake pressure reduction function with a second target gradient for a second wheel brake cylinder that is above the first target gradient. In method step S5, the motor of the motorized piston-cylinder device is activated so that the activated motor reduces at least one fluid receiving volume of the motorized piston-cylinder device. At the same time, in method step S6, at least one second valve is switched at least partially open. However, as method step S7 performed during the transfer of brake fluid caused by method step S6, i.e., as method step S7 performed while the brake fluid is being transferred from at least one liquid receiving volume reduced by the activated motor into a second wheel brake cylinder via at least one second switching valve switched to be at least partially open, the transfer of brake fluid from the at least one reduced liquid receiving volume is blocked multiple times using at least one first valve switched to be closed for a short period of time.

[0048] Thus, the implementation of the method described here also provides the advantages already mentioned above. [Explanation of symbols]

[0049] 10 Control device 10a electronic equipment 12a, 12b First wheel brake cylinder 14a, 14b Second wheel brake cylinder 16 First brake circuit 18 Second brake circuit 20 Electric piston cylinder device 20c, 20d Liquid receiving area 22a, 30a First valve 22b, 30b Second valve 26a, 26b Pump M Motor for electric piston cylinder device M P Pump motor

Claims

1. A control device (10) for a power braking system of a vehicle, comprising: The power brake system includes an electronic mechanism (10a) designed and / or programmed as follows: the electronic mechanism (10a) can be used to activate a motor (M) of an electric piston cylinder device (20) of the power brake system, so that the activated motor (M) can vary at least one liquid receiving volume (20c, 20d) of the electric piston cylinder device (20); and the electronic mechanism (10a) can be used to control at least one first valve (22a, 30a) of the power brake system and at least one second valve (22a, 30a) of the power brake system. and one second valve (22b, 30b), and the electronic mechanism is designed and / or programmed so that two first wheel brake cylinders (12a, 12b) of the power brake system are hydraulically coupled to the at least one liquid receiving volume (20c, 20d) via at least the at least one first valve (22a, 30a) and two second wheel brake cylinders (14a, 14b) of the power brake system are hydraulically coupled to the at least one liquid receiving volume (20c, 20d) via at least the at least one second valve (22b, 30b). In the control device (10), The electronic mechanism (10a) is additionally designed and / or programmed so that, by means of the electronic mechanism (10a), it is possible to simultaneously perform a brake pressure maintaining or increasing function for the first wheel brake cylinder (12a, 12b) and a brake pressure reducing function for the second wheel brake cylinder (14a, 14b), at least one fluid receiving volume (20c, 20d) expanded by the activated motor (M) from the first wheel brake cylinder (12a, 12b). and wherein the electronic mechanism (10a) is additionally designed and / or programmed in such a way that the transfer of brake fluid into the at least one wheel brake cylinder (14a, 14b) is prevented by the at least one first valve (22a, 30a) being switched to a closed state, and that brake fluid can be sucked from the second wheel brake cylinder (14a, 14b) into the at least one enlarged liquid receiving volume (20c, 20d) via the at least one second valve (22b, 30b) being switched to an at least partially open state.

2. The electronic mechanism (10a) is additionally designed and / or programmed to allow the electronic mechanism (10a) to simultaneously perform a brake pressure increase function for the first wheel brake cylinder (12a, 12b) and a brake pressure decrease function for the second wheel brake cylinder (14a, 14b), by means of which the first wheel brake cylinder (12a, 12b) is supplied with fluid from the first wheel brake cylinder (12a, 12b) into the at least one fluid receiving volume (20c, 20d) expanded by the activated motor (M). While the transfer of brake fluid to the at least one wheel brake cylinder (14a, 14b) is prevented by the at least one first valve (22a) switched to a closed state, and while brake fluid can be sucked from the second wheel brake cylinder (14a, 14b) into the at least one enlarged liquid receiving volume (20c, 20d) through the at least one second valve (22b) switched to an at least partially open state, the pump motor (M) of at least one pump (26a, 26b) of the power brake system is simultaneously Ｐ 2. The control device (10) according to claim 1, wherein the electronic mechanism (10a) is additionally designed and / or programmed to additionally activate a brake fluid pump (26a) by the at least one pump (26a) so that brake fluid can be delivered into the first wheel brake cylinder (12a, 12b) by the activated at least one pump (26a).

3. The electronic mechanism (10a) is additionally designed and / or programmed so that, by means of the electronic mechanism (10a), a first brake pressure reduction function with a first target gradient for the first wheel brake cylinder (12a, 12b) and a second brake pressure reduction function with a second target gradient above the first target gradient for the second wheel brake cylinder (14a, 14b) can be simultaneously performed, and the at least one second wheel brake cylinder (14a, 14b) that is switched at least partially open is selected from the second wheel brake cylinder (14a, 14b).

3. The control device (10) according to claim 1 or 2, wherein the electronic mechanism (10a) is additionally designed and / or programmed in such a way that during the transfer of brake fluid via the valve (22b, 30b) into the at least one liquid receiving volume (20c, 20d) enlarged by the activated motor (M), the transfer of brake fluid from the first wheel brake cylinder (12a, 12b) into the at least one enlarged liquid receiving volume (20c, 20d) is interrupted multiple times by the at least one first valve (22a, 30a) being switched to closed for a short period of time.

4. In a power brake system for a vehicle, A control device (10) according to any one of claims 1 to 3; The electric piston cylinder device (20), the motor (M) of which can be activated by the electronic mechanism (10a) of the control device (10) as follows: the activated motor (M) can be activated so that the at least one liquid receiving volume (20c, 20d) of the electric piston cylinder device (20) can be varied; two first wheel brake cylinders (12a, 12b) that can be arranged or are arranged on a first axle of the vehicle and two second wheel brake cylinders (14a, 14b) that can be arranged or are arranged on a second axle of the vehicle; the first and second valves (22a, 22b, 30a, 30b) switchable using the electronic mechanism (10a), wherein the first wheel brake cylinder (12a, 12b) is hydraulically coupled to the at least one liquid receiving volume (20c, 20d) via at least the at least one first valve (22a, 30a) and the second wheel brake cylinder (14a, 14b) is hydraulically coupled to the at least one liquid receiving volume (20c, 20d) via at least the at least one second valve (22b, 30b); A power brake system for a vehicle.

5. 5. The power brake system of claim 4, wherein the first wheel brake cylinders (12a, 12b) are hydraulically coupled to a first brake circuit (16) of the power brake system, and the second wheel brake cylinders (14a, 14b) are hydraulically coupled to a second brake circuit (18) of the power brake system, the only first valve (22a) is the selector valve (22a) of the first brake circuit (16), and the only second valve (22b) is the selector valve (22b) of the second brake circuit (18).

6. One first wheel brake cylinder (12a) of the plurality of first wheel brake cylinders and one second wheel brake cylinder (14a) of the plurality of second wheel brake cylinders are hydraulically connected to a first brake circuit (16) of the power brake system, and another first wheel brake cylinder (12b) of the plurality of first wheel brake cylinders and another second wheel brake cylinder (14b) of the plurality of second wheel brake cylinders are hydraulically connected to a second brake circuit (18) of the power brake system, and two first valves (30a) are hydraulically connected to the first brake circuit (16) of the power brake system.

5. The power brake system of claim 4, wherein the first and second valves are a wheel intake valve (30a) supported upstream of the first wheel brake cylinder (12a) of the first brake circuit (16) and a wheel intake valve (30a) supported upstream of the first wheel brake cylinder (12b) of the second brake circuit (18), and the two second valves are a wheel intake valve (30b) supported upstream of the second wheel brake cylinder (14a) of the first brake circuit (16) and a wheel intake valve (30b) supported upstream of the second wheel brake cylinder (14b) of the second brake circuit (18).

7. 7. The power brake system according to claim 4, wherein the electric piston cylinder device (20) is a DPB device (20).

8. 1. A method of operating a power brake system of a vehicle, comprising: Simultaneously performing a brake pressure maintaining function or a brake pressure increasing function for two first wheel brake cylinders (12a, 12b) of the power brake system arranged on a first axle of the vehicle and a brake pressure reducing function for two second wheel brake cylinders (14a, 14b) of the power brake system arranged on a second axle of the vehicle by at least the following steps: a step (S1) of starting a motor (M) of an electric piston cylinder device (20) of the power brake system as follows: starting the motor (M) so that at least one liquid receiving volume (20c, 20d) of the electric piston cylinder device (20) is enlarged by the started motor (M); a step (S2) of switching at least one first valve (22a, 30a) of the power brake system in such a way that, while the first wheel brake cylinder (12a, 12b) is hydraulically coupled to the at least one liquid receiving volume (20c, 20d) via the at least one first valve (22a, 30a), the transfer of brake fluid from the first wheel brake cylinder (12a, 12b) into the at least one liquid receiving volume (20c, 20d) enlarged by the activated motor (M) is prevented by the at least one first valve (22a, 30a) being switched closed; a step (S3) of switching at least one second valve (22b, 30b) of the power brake system such that, while the second wheel brake cylinder (14a, 14b) is hydraulically coupled to the at least one liquid receiving volume (20c, 20d) via the at least one second valve (22b, 30b), brake fluid is drawn from the second wheel brake cylinder (14a, 14b) into the enlarged at least one liquid receiving volume (20c, 20d) via the at least one second valve (22b, 30b) that is switched at least partially open; The method is characterized by simultaneously carrying out the steps of:

9. In order to simultaneously perform a brake pressure increase function for the first wheel brake cylinder (12a, 12b) and a brake pressure decrease function for the second wheel brake cylinder (14a, 14b), a pump motor (M) of at least one pump (26a, 26b) of the power brake system is additionally operated while the transfer of brake fluid from the first wheel brake cylinder (12a, 12b) into the at least one liquid receiving volume (20c, 20d) enlarged by the activated motor (M) is prevented by the at least one first valve (22a) switched to closed, and at the same time, brake fluid is sucked from the second wheel brake cylinder (14a, 14b) into the at least one liquid receiving volume (20c, 20d) enlarged through the at least one second valve (22b) switched to at least partially open. Ｐ 9. The method according to claim 8, further comprising: actuating at least one pump (26a) so that brake fluid is delivered into the first wheel brake cylinder (12a, 12b) by the actuated at least one pump (26a).

10. 10. The method according to claim 8 or 9, wherein during the transfer of brake fluid from the at least one fluid receiving volume (20c, 20d) reduced by the activated motor (M) into the second wheel brake cylinder (14a, 14b) via the at least one second valve (22b, 30b) switched at least partially open, the transfer of brake fluid from the at least one reduced fluid receiving volume (20c, 20d) is interrupted several times by the at least one first valve (22a, 30a) switched at a time to close for a short period of time (S5-S7), so as to be able to simultaneously perform a first brake pressure reduction function for the first wheel brake cylinder (12a, 12b) with a first target gradient and a second brake pressure reduction function for the second wheel brake cylinder (14a, 14b) with a second target gradient higher than the first target gradient.

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