Control device for a vehicle's brake system and method for at least partially emptying the fluid reservoir of a vehicle's brake system.

Abstract

The present invention relates to a control device (10) for a braking system of a vehicle having at least one brake circuit (12a, 12b) with a fluid reservoir (16a, 16b), the control device (10) comprising an electronic circuit device (26) designed and / or programmed to switch a high pressure switching valve (18a, 18b) of said brake circuit (12a, 12b) to an at least partially open state for a preset or defined opening time, whereby during said opening time brake fluid is able to move from said fluid reservoir (16a, 16b) through the at least partially opened high pressure switching valve (18a, 18b) into a master brake cylinder (14) of said braking system to which said brake circuit (12a, 12b) is connected. [Solution] In this case, the electronic circuit device (26) is additionally designed and / or programmed to control and / or maintain the switching valves (20a, 20b) of the brake circuits (12a, 12b), the only wheel outlet valve of the brake circuits and / or all wheel outlet valves (22a, 22b, 24a, 24b) of the brake circuits (12a, 12b) in a state in which brake fluid movement from the fluid reservoir (16a, 16b) is blocked by the respective valves (20a, 20b, 22a, 22b, 24a, 24b) during their entire opening time.

Description

Technical Field

[0001] The present invention relates to a control device for a braking system of a vehicle having at least one braking circuit with a liquid reservoir. The present invention also relates to a braking system for a vehicle. Furthermore, the present invention relates to a method for at least partially emptying the brake fluid reservoir of a braking system of a vehicle.

Background Art

[0002] According to the prior art, for example, Patent Document 1, various braking system types are known, and in this case, a braking system of such a type has at least one braking circuit with a liquid reservoir.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The present invention provides a control device for a braking system of a vehicle having at least one braking circuit with a liquid reservoir having the features of claim 1, a braking system for a vehicle having the features of claim 4, and a method for at least partially emptying the brake fluid reservoir of a braking system of a vehicle having the features of claim 8.

Advantages of the Invention

[0005] The present invention provides a suitable possibility for at least partially emptying the fluid reservoir of a vehicle's brake system, and at the same time, for restricting or blocking the flow of brake fluid through a single wheel outlet valve or all wheel outlet valves of a brake circuit configured with at least the emptied fluid reservoir. Thus, the conventional need to provide at least one wheel outlet valve of a brake circuit configured with a fluid reservoir to be emptied with a unique filter, such as a net filter or mesh filter, for moving brake fluid from the fluid reservoir through its respective valve is eliminated. This results in a less expensive manufacturing possibility for at least one wheel outlet valve of a brake circuit configured with a fluid reservoir to be emptied. Therefore, using the present invention increases the design freedom for at least one wheel outlet valve of a brake circuit configured with a fluid reservoir. This can further help reduce the number of outlet valve types to be equipped when manufacturing a brake system using the present invention.

[0006] According to a preferred embodiment of the control device, the electronic circuit device is designed and / or programmed to control or maintain the switching valve of the brake circuit in a closed state for the entire open time. The closing control or maintenance of the switching valve preferably serves to prevent undesirable brake fluid movement from the fluid reservoir through at least one wheel outlet valve of the brake circuit during the open time.

[0007] Selectively or supplementarily, the electronic circuitry is designed and / or programmed to control and / or maintain in a closed state for the entire open time at least one of the single wheel outlet valves or multiple wheel outlet valves of the brake circuit, which is designed and oriented to allow brake fluid to pass from the fluid reservoir in at least a partially open state. Such a form of design / programming of the control device / electronic circuitry also ensures that undesirable brake fluid movement from the fluid reservoir through at least one wheel outlet valve is blocked for the entire open time.

[0008] The aforementioned advantages are also guaranteed in a brake system for a vehicle, comprising a suitable control device, at least one brake circuit with a fluid reservoir connected to the master brake cylinder of the brake system, and a high-pressure switching valve controllable by the electronic circuit device of the control device, in which case the brake circuit further comprises a switching valve, a single wheel outlet valve and / or multiple wheel outlet valves, and the switching valve, the single wheel outlet valve and / or multiple wheel outlet valves are controllable by the electronic circuit device.

[0009] In a preferred form, a single wheel outlet valve and / or multiple wheel outlet valves each have only one filter for the movement of brake fluid from the wheel brake cylinder, which is disposed in accordance with each valve, to the fluid reservoir. Thus, in a preferred form, each single wheel outlet valve or multiple wheel outlet valve is filterless for the movement of brake fluid from the fluid reservoir through its respective valve. This helps reduce the manufacturing cost of at least one wheel outlet valve in a brake circuit configured with a fluid reservoir to be emptied, and consequently, the brake system becomes less expensive.

[0010] For example, a brake circuit has a first wheel outlet valve and a second wheel outlet valve as its wheel outlet valves, a first pipeline section of the brake circuit opening to the master brake cylinder branches to a switching valve and a high-pressure switching valve, a second pipeline section of the brake circuit opening to the switching valve branches to a first wheel inlet valve and a second wheel inlet valve, and the first wheel brake cylinder is connected to or can be connected to a third pipeline section of the brake circuit which branches to a first wheel inlet valve and a first wheel outlet valve, The second wheel brake cylinder is connected to or connectable to a fourth piping section of the brake circuit, which branches to a second wheel inlet valve and a second wheel outlet valve, and opens to the suction side of the pump device of the brake circuit. The fifth piping section of the brake circuit branches to a first wheel outlet valve and a second wheel outlet valve, and a liquid reservoir is connected to the fifth piping section, opening to the discharge side of the pump device. The sixth piping section of the brake circuit opens to the second piping section and opens to a high-pressure switching valve. The seventh piping section of the brake circuit opens to the fifth piping section. Therefore, the present invention can be used in many brake system types that are commonly installed in conventional forms in various vehicle / automobile types. However, it should be noted that the hydraulic configuration of the brake circuit equipped with a liquid reservoir described herein is merely an example.

[0011] The advantages described above can also be obtained by performing a corresponding method to at least partially empty the fluid reservoir of the vehicle's brake system. It should be made clear that the method for at least partially emptying the fluid reservoir of the vehicle's brake system according to the above-described embodiments of the control device and / or brake system can be further improved. [Brief explanation of the drawing]

[0012] [Figure 1]This is a schematic diagram of one embodiment of a control device or a brake system that works in conjunction with this control device. [Figure 2a] This is a flowchart illustrating a first embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system. [Figure 2b] This is a time graph illustrating a first embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system. [Figure 2c] This is a schematic partial diagram of a brake system illustrating a first embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system. [Figure 2d] This is a schematic partial diagram of a brake system illustrating a first embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system. [Figure 3a] This is a flowchart illustrating a second embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system. [Figure 3b] This is a time graph illustrating a second embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system. [Figure 3c] This is a schematic partial diagram of a brake system illustrating a second embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system. [Figure 3d] This is a schematic partial diagram of a brake system illustrating a second embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system. [Modes for carrying out the invention]

[0013] Other features and advantages of the present invention will be described below with reference to the drawings.

[0014] Figure 1 shows a schematic diagram of one embodiment of a control device or a brake system that works in conjunction with this control device.

[0015] The control device 10 described below can be interlocked with (substantially) all brake systems having at least one brake circuit 12a and 12b. These brake circuits 12a and 12b are connected to the master brake cylinder 14 of the brake system, and are configured to include a liquid reservoir 16a or 16b and a high-pressure switching valve 18a or 18b, and additionally further have one switching valve 20a or 20b and / or at least one wheel outlet valve 22a, 22b, 24a and 24b. Similarly, the usability of this control device 10 is not limited to a unique vehicle type / automobile type of a vehicle / automobile equipped with each brake system.

[0016] The control device 10 has an electronic circuit device 26, and this electronic circuit device 26 is designed and / or programmed to switch the high-pressure switching valve 18a or 18b of the brake circuit 12a or 12b equipped with the liquid reservoir 16a or 16b to be emptied to an at least partially open state by at least one control signal 18s for a preset or defined opening time. In such a manner, the control device 10 / its electronic circuit device 26 takes into consideration that the brake fluid can move / flow into the master brake cylinder 14 through the at least partially open high-pressure switching valve 18a or 18b of the same brake circuit 12a or 12b from the liquid reservoir 16a or 16b during the opening time. Therefore, the volume balance of this brake system can be corrected by at least partially emptying the liquid reservoir 16a or 16b.

[0017] Furthermore, the electronic circuit device 26 is designed and / or programmed to control and / or maintain, using at least one control signal 20s and 22s during the entire opening time, the switching valve 20a or 20b of the brake circuit 12a or 12b equipped with the liquid reservoir 16a or 16b to be emptied, the single wheel outlet valve of each brake circuit 12a or 12b, and / or all wheel outlet valves 22a, 22b, 24a and 24b of each brake circuit 12a or 12b, so that the movement of brake fluid from each liquid reservoir 16a or 16b is blocked by each valve 20a, 20b, 22a, 22b, 24a and 24b. Therefore, the control device 10 / its electronic circuit device 26 restricts at least undesirable brake fluid flow from the fluid reservoir 16a or 16b by at least one wheel outlet valve 22a, 22b, 24a, and 24b of each brake circuit 12a or 12b. Undesirable brake fluid flow from the fluid reservoir 16a or 16b can be (almost) completely blocked by at least one wheel outlet valve 22a, 22b, 24a, and 24b of each brake circuit 12a or 12b, insofar as the electronic circuit device 26 is designed and / or programmed to control and / or maintain the state in which brake fluid movement from each fluid reservoir 16a or 16b is blocked by the respective valves 22a, 22b, 24a, and 24b during the entire opening time.

[0018] Even if the flow of brake fluid from the fluid reservoir 16a or 16b is restricted or (almost) completely blocked by at least one wheel outlet valve 22a, 22b, 24a or 24b, the conventional need to form / equip at least one wheel outlet valve 22a, 22b, 24a and 24b with a unique filter, such as a corresponding net filter or mesh filter, for moving brake fluid from the fluid reservoir 16a or 16b through the respective valves 22a, 22b, 24a and 24b is eliminated. Thus, preferably the sole wheel outlet valve or the wheel outlet valves 22a, 22b, 24a and 24b each have only one filter 23a, 23b, 25a and 25b for the movement of brake fluid from the wheel brake cylinders 28a, 28b, 30a and 30b corresponding to the respective valves 22a, 22b, 24a and 24b to the fluid reservoir 16a or 16b. This can also be rephrased as the sole wheel outlet valve or the wheel outlet valves 22a, 22b, 24a and 24b each moving brake fluid from the fluid reservoir 16a or 16b through the respective valves 22a, 22b, 24a and 24b without a filter. This reduces the manufacturing cost for at least one wheel outlet valve 22a, 22b, 24a or 24b of the brake system in conjunction with the control device 10 and expands its manufacturability.

[0019] By eliminating the unique filter for moving brake fluid from the fluid reservoir 16a or 16b through the respective wheel outlet valves 22a, 22b, 24a or 24b, a high degree of freedom in the design of each wheel outlet valve 22a, 22b, 24a or 24b of the brake circuit 12a or 12b configured with the fluid reservoir 16a or 16b is enabled. This can be utilized to reduce the types of outlet valves used during the manufacture of each brake system.

[0020] To obtain the aforementioned advantages, it is sufficient that the electronic circuit device 26 is designed and / or programmed to control or maintain the switching valve 20a or 20b of the brake circuit 12a or 12b in its closed state for the entire duration that the high-pressure switching valve 18a or 18b of the same brake circuit 12a or 12b is open. (The switching valve 20a or 20b controlled or maintained in a closed state may be interpreted as a valve 20a or 20b that, based on its design and orientation, allows brake fluid to pass from the liquid reservoir 16a or 16b through at least one wheel outlet valve 22a, 22b, 24a and 24b of the brake circuit 12a or 12b in a state that is at least partially open.) The advantages are similarly guaranteed if the electronic circuit device 26 is designed and / or programmed to control and / or maintain in a closed state the entire time that the single wheel outlet valve of the brake circuit 12a or 12b, or at least one of the wheel outlet valves 22a, 22b, 24a and 24b of the brake circuit 12a or 12b, which is designed and oriented to allow brake fluid to pass from the liquid reservoir 16a or 16b in a state that is at least partially open, the high-pressure switching valve 18a or 18b of the same brake circuit 12a or 12b is closed.

[0021] During the opening time, the high-pressure switching valve 18a or 18b of the brake circuit 12a or 12b having the liquid reservoir 16a or 16b to be emptied is controlled to be at least partially open, and this opening time may be (fixed) preset in the electronic circuit device 26. In a preferred embodiment, the electronic circuit device 26 may be designed and / or programmed to (automatically) determine the opening time, taking into account the reservoir pressure present in the liquid reservoir 16a or 16b to be emptied. Determination of the opening time by the electronic circuit device 26 may be interpreted as waiting until a preset event that ends the opening time. In particular, the electronic circuit device 26 may be designed and / or programmed to "wait" until the driver firmly presses the brake pedal again, and / or until the reservoir pressure in the fluid reservoir 16a or 16b drops to less than or equal to the response pressure of the respective fluid reservoir 16a or 16b, as brake fluid flows from the fluid reservoir 16a or 16b to the master brake cylinder 14 through at least partially open high-pressure switching valve 18a or 18b of the same brake circuit 12a or 12b.

[0022] As shown in the diagram in Figure 1, the fluid reservoir 16a or 16b to be emptied may be the reservoir chambers 16a and 16b, particularly the low-pressure reservoir chambers 16a and 16b, which are incorporated within the hydraulic unit of each brake system. However, the usability of the control device 10 is not limited to specific fluid reservoir types. As also shown in the diagram in Figure 1, the control device 10 / its electronic circuit unit 26 may be designed to simultaneously empty multiple fluid reservoirs 16a and 16b of multiple brake circuits 12a and 12b of the same brake system.

[0023] As a simple example, the brake system in Figure 1 has two brake circuits 12a and 12b, each having one first wheel brake cylinder 28a or 28b and one second wheel brake cylinder 30a or 30b. Additionally, the brake circuits 12a and 12b have a first wheel outlet valve 22a or 22b and a second wheel outlet valve 24a or 24b, respectively, as their wheel outlet valves 22a, 22b, 24a, and 24b. Each brake circuit 12a and 12b has a first conduit section 32a or 32b that opens to the master brake cylinder 14, and these first conduit sections 32a or 32b branch to their switching valve 20a or 20b and high-pressure switching valve 18a or 18b. The second conduit section 34a or 34b of each brake circuit 12a or 12b, which opens into the switching valve 20a or 20b, branches to the first wheel inlet valve 36a or 36b and its second wheel inlet valve 38a or 38b. The first wheel brake cylinder 28a or 28b is connected to / connectable to the third conduit section 40a or 40b of each brake circuit 12a or 12b, which branches to the first wheel inlet valve 36a or 36b and the first wheel outlet valve 22a or 22b. Accordingly, a second wheel brake cylinder 30a or 30b is connected to / connectable to a fourth conduit section 42a or 42b of the same brake circuit 12a or 12b, which branches to a second wheel inlet valve 38a or 38b and a second wheel outlet valve 24a or 24b.

[0024] A fifth conduit section 46a or 46b of each brake circuit 12a or 12b, opening to the suction side of the pump device 44a or 44b, branches to a first wheel outlet valve 22a or 22b and a second wheel outlet valve 24a or 24b, in which case the liquid reservoir 16a or 16b of each brake circuit 12a or 12b is connected to the fifth conduit section 46a or 46b. A sixth conduit section 48a or 48b of each brake circuit 12a or 12b, opening to the discharge side of the pump device 44a or 44b, additionally opens to a second conduit section 34a or 34b. Furthermore, a seventh conduit section 50a or 50b of each brake circuit 12a or 12b opens to a high-pressure switching valve 18a or 18b and a fifth conduit section 46a or 46b.

[0025] In an additional embodiment, at least one relief valve 52a or 52b may be incorporated in a fifth piping section 46a or 46b between the fluid reservoir 16a or 16b and the pumping device 44a or 44b. Similarly, a filter 54a or 54b, a throttle 56a or 56b and / or a check valve 58a or 58b may be located in a sixth piping section 48a or 48b. In a preferred form, a brake fluid reservoir tank 60 is further connected to the master brake cylinder 14. In an optional form, a brake booster 62 may be pre-installed on the master brake cylinder 14. Furthermore, at least one feed pressure sensor 64 and / or pressure sensors may be connected to at least one brake circuit 12a and 12b.

[0026] Figures 2a to 2d show a flowchart, a time graph, and a schematic partial diagram of the brake system to illustrate a first embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system.

[0027] The method described below can be implemented in (almost) all brake systems having at least one brake circuit 12a connected to the master brake cylinder 14 of the brake system, comprising a fluid reservoir 16a and a high-pressure switching valve 18a, and further comprising one additional switching valve 20a and / or at least one wheel outlet valve 22a and 24a. Similarly, the feasibility of this method is not limited to specific vehicle / automobile models of vehicles / automobile models equipped with each brake system. The "drawn representation" of this method using the master brake cylinder 14 and at least the first brake circuit 12a of the brake system in Figure 1 is provided for better understanding only.

[0028] In the embodiments described herein, there is an optional method step S1 before emptying the liquid reservoir, but its execution may be omitted. In this method step S1, it is determined whether the adjustment stroke x of the brake pedal 66 connected to the master brake cylinder 14, generated by the driver braking force F, from its initial unoperated position is non-zero, whether the time derivative of this adjustment stroke x is greater than zero or equal to zero, and whether the generator brake torque M corresponding to the adjustment stroke x is non-zero. gen The system is inspected to determine whether the target brake torque M0 is achievable by at least one electric motor of a regeneratively driven vehicle. The adjustment stroke x may be measured, for example, using a rod stroke sensor 68.

[0029] The time graph in Figure 2b shows the target brake torque M0 and the generator brake torque M. gen The volume V in the liquid reservoir 16a of the first brake circuit 12a, the open state of the first wheel outlet valve 22a of the first brake circuit 12a, and the open state of the high-pressure switching valve 18a of the first brake circuit 12a are shown along the time axis t.

[0030] From time t0, the driver operates the brake pedal 66. The adjustment stroke x is not zero, the time derivative of the adjustment stroke x is greater than zero or equal to zero, and the target brake torque M0 corresponding to the adjustment stroke x is equal to the generator brake torque M gen To the extent that it is feasible, method step S2 schematically shown in Figure 2c is performed. In method step S2, the switching valve 20a of the first brake circuit 12a, the first wheel inlet valve 36a disposed corresponding to the first wheel brake cylinder 28a of the first brake circuit 12a, and the first wheel outlet valve 22a disposed corresponding to the first wheel brake cylinder 28a are controlled and / or maintained in at least a partially open state Φo, as shown in the drawing by arrow 70, so that the brake fluid pushed out from the master brake cylinder 14 by the driver braking force F is moved to the fluid reservoir 16a via the switching valve 20a, the first wheel inlet valve 36a, and the first wheel outlet valve 22a. In a preferred configuration, the second wheel inlet valve 38a, which is disposed in correspondence with the second wheel brake cylinder 30a of the first brake circuit 12a, and the second wheel outlet valve 24a, which is disposed in correspondence with the second wheel brake cylinder 30a of the first brake circuit 12a, are controlled and / or maintained in a closed state simultaneously, thereby preventing the movement of brake fluid into the second wheel brake cylinder 30a. Thus, a first brake pressure exists in the first wheel brake cylinder 28a, which is the same as the response pressure of the fluid reservoir 16a, while the second brake pressure present in the second wheel brake cylinder 30a can be maintained at (approximately) the same pressure as atmospheric pressure. The high-pressure switching valve 18a is also controlled / maintained in its closed state Φc. This method step S2 continues even after the time derivative of the adjustment stroke x becomes zero at time t1.

[0031] At time t2, the time derivative of the adjustment stroke x of the brake pedal 66 becomes less than zero (the target brake torque M0 corresponding to the adjustment stroke x is further reduced by the generator brake torque M genIf it is confirmed that (even though it is feasible as) the liquid reservoir 16a is to be at least partially emptied, then in another optional method step S3, it is checked whether it is desirable to empty the liquid reservoir 16a at least partially. For example, this may be done by calculating whether the first brake pressure in the first wheel brake cylinder 28a is lower than the reservoir pressure in the liquid reservoir 16a. If the first brake pressure in the first wheel brake cylinder 28a is not lower than the reservoir pressure in the liquid reservoir 16a, then method step S2 is continued. Otherwise, the liquid reservoir 16a is at least partially emptied.

[0032] In the embodiment described herein, the process of at least partially emptying the liquid reservoir 16a begins at time t2. To this end, in method step S4, the high-pressure switching valve 18a is controlled to an at least partially open state Φo, as illustrated by arrow 72 in Figure 2d, for a preset or specified opening time, during which brake fluid flows from the liquid reservoir 16a into the master brake cylinder 14 through the at least partially open high-pressure switching valve 18a.

[0033] Method step S5 is performed simultaneously with method step S4, in which the switching valve 20a of the first brake circuit 12a, the single wheel outlet valve of the first brake circuit 12a, and / or all wheel outlet valves 22a and 22b of the first brake circuit 12a are controlled or maintained in a state in which the movement of brake fluid from the liquid reservoir 16a is blocked by the respective valves 20a, 22a and 24a during the entire opening time. For this purpose, in the embodiment described herein, for example, as method step S5a of this method, the first wheel outlet valve 22a of the first brake circuit 12a, which, based on its design and orientation, allows brake fluid to pass from the liquid reservoir 16a in at least a partially open state Φo, is controlled to its closed state Φc during the entire opening time. Furthermore, the second wheel outlet valve 24a of the first brake circuit 12a is maintained to its closed state Φc during the entire opening time. As can be seen from Figure 2d, by performing method step S5a, the movement of brake fluid from the liquid reservoir 16a is completely blocked by the outlet valves 22a and 24a of the brake circuit 12a. Therefore, by performing the method described herein, the advantages mentioned above may also be beneficial for the brake system used for this purpose.

[0034] The release time may be interpreted as an invariant, preset release time. Similarly, the release time may be self-defined. For this purpose, for example, the release time may be defined by considering the pressure difference obtained by subtracting the first brake pressure in the first wheel brake cylinder 28a from the reservoir pressure in the liquid reservoir 16a. Similarly, the release time is "waited" until at least one preset event occurs. In particular, the release time is "waited" until the time derivative of the adjustment stroke x of the brake pedal 66 is greater than zero or equal to zero and / or the reservoir pressure in the liquid reservoir 16a is less than or equal to the response pressure.

[0035] As can be seen in the time graph of Figure 2b, when the adjustment stroke x of the brake pedal 66 increases later from time t3, the first wheel outlet valve 22a is opened again, while the high-pressure switching valve 18a may remain in its at least partially open state Φo. When the adjustment stroke x of the brake pedal decreases again at time t4, the volume V in the liquid reservoir 16a is immediately moved again from the liquid reservoir 16a to the master brake cylinder 14 via the high-pressure switching valve 18a, which is in its at least partially open state Φo, by newly controlling the first wheel outlet valve 22a to its closed state Φc.

[0036] Figures 3a to 3d show flowcharts, time graphs, and schematic partial diagrams of the brake system to illustrate a second embodiment of a method for at least partially emptying the fluid reservoir of a vehicle's brake system.

[0037] For the feasibility of the methods described below, please refer to the description of the above-mentioned embodiments.

[0038] As can be seen from the flowchart in Figure 3a, the method described herein already includes the method steps S1 to S5 described above. In the time graph in Figure 3b, the target brake torque M0 and the generator brake torque M gen The volume V in the liquid reservoir 16a of the first brake circuit 12a, the open state of the first wheel outlet valve 22a of the first brake circuit 12a, the open state of the high-pressure switching valve 18a of the first brake circuit 12a, the open state of the switching valve 20a of the first brake circuit 12a, and the open state of the check valve 21a, which is arranged parallel to the switching valve 20a, are shown along the time axis t. Time points t1 to t4 correspond to the description of the embodiment above.

[0039] Unlike the embodiments described herein, in the method described herein, method step S5b is performed as method step S5 from time t2, in method step S5b, the switching valve 20a of the first brake circuit 12a is controlled or maintained in its closed state Φc for the entire opening time. (The switching valve 20a controlled or maintained in its closed state may be interpreted as a valve 20a that, based on its design and orientation, allows brake fluid to pass from the liquid reservoir 16a through at least one wheel outlet valve 22a and 24a in at least a partially open state Φo.) Simultaneously, the first wheel outlet valve 22a is maintained in its at least partially open state Φo for the entire opening time. As can be seen in Figure 3c, even though the first wheel outlet valve 22a is in its at least partially open state Φo, the closing of the switching valve 20a of the first brake circuit 12a ensures that any undesirable brake fluid flow from the fluid reservoir 16a through at least one wheel outlet valve 22a and 24a is limited to a negligibly weak flow motion that occurs only briefly through the first wheel outlet valve 22a. Thus, the aforementioned advantages may also be beneficial for the brake system used for this purpose by implementing the method described herein. While the fluid reservoir 16a is at least partially emptied as indicated by arrow 72 in Figure 3c, the check valve 21a, positioned parallel to the switching valve 20a, remains in its closed state Φc.

[0040] As illustrated by arrow 74 in Figure 3d, the driver can use their braking force F to increase the adjustment stroke x of the brake pedal 66 at time t3, thereby moving the brake fluid pushed out from the master brake cylinder 14 into the fluid reservoir 16a via the check valve 21a, the at least partially open first wheel inlet valve 36a, and the at least partially open wheel outlet valve 22a, even though the switching valve 20a is in its closed state Φc. Therefore, it is not necessary to switch the switching valve 20a to its at least partially open state Φo at time t3. Thus, the switching valve 20a may remain in its closed state Φc at time t2 after closing, throughout the entire braking period shown in the flowchart of Figure 3b. Accordingly, the first wheel outlet valve 22a may also remain in its at least partially open state Φo at time t0 during the entire braking period after opening.

[0041] Therefore, when the embodiments described herein are implemented, no or almost no valve switching noise is generated. Moreover, in order to implement the embodiments described herein, it is not necessary to quickly open the first wheel outlet valve 22a when the adjustment stroke x of the brake pedal 66 suddenly increases according to the braking flowchart shown in Figure 3b. Therefore, there is no need to worry about undesirable damming pressure in the first wheel outlet valve 22a which is opened with a delay.

[0042] For other steps of the method shown in Figures 3a to 3d, refer to the embodiments shown in Figures 2a to 2d described earlier. [Explanation of Symbols]

[0043] 10 Control device 12a, 12b Brake Circuit 14 Master brake cylinder 16a, 16b Liquid reservoir, reserve chamber, low-pressure reserve chamber 18a, 18b High-pressure switching valve 18s, 20s, 22s control signals 20a, 20b switching valve 22a, 22b First wheel outlet valve 24a, 24b Second wheel outlet valve 26 Electronic circuit equipment 28a, 28b First wheel brake cylinder 30a, 30b Second wheel brake cylinder 32a, 32b First pipeline division 34a, 34b Second pipeline division 36a, 36b First wheel inlet valve 38a, 38b Second wheel inlet valve 40a, 40b Third pipeline division 42a, 42b Fourth pipeline division 44a, 44b Pumping device 46a, 46b Fifth pipeline division 48a, 48b Sixth pipeline division 50a, 50b Seventh pipeline division 52a, 52b Relief valve 54a, 54b filters 56a, 56b aperture 58a, 58b Check valve 60 Brake fluid reservoir tank 62 Brake booster 64 Feed pressure sensor 66 Brake pedal 68 Rod Stroke Sensor 70 Arrows 72 Arrows 74 Arrows F Driver's braking force M gen Generator brake torque M0 Target Brake Torque S1 Optional Method Step S2, S3, S4, S5, S5a, S5b Method Steps t Time axis Time point t0 x Adjustment stroke Φc Closed state Φo At least partially open state Time points t1, t2, t3, t4 V Volume

Claims

1. A control device (10) for a vehicle brake system having at least one brake circuit (12a, 12b) equipped with liquid reservoirs (16a, 16b), The brake system has an electronic circuit device (26) which is designed and / or programmed to switch the high-pressure switching valves (18a, 18b) of the brake circuits (12a, 12b) to a state that is at least partially open for a preset or specified opening time, thereby allowing brake fluid to move into the master brake cylinder (14) to which the brake circuits (12a, 12b) are connected, via the high-pressure switching valves (18a, 18b) which are at least partially open from the liquid reservoir (16a, 16b) during the opening time. A control device (10) for a vehicle brake system, characterized in that the electronic circuit device (26) is further controlled to keep at least one of the wheel outlet valves (22a, 22b, 24a, 24b) of the brake circuit (12a, 12b) closed during the open time of the high-pressure switching valves (18a, 18b), thereby maintaining a state in which brake fluid from the liquid reservoir (16a, 16b) is prevented from moving into the master brake cylinder (14) without passing through the high-pressure switching valves (18a, 18b).

2. The control device (10) according to claim 1, wherein the electronic circuit device (26) is designed and / or programmed to control or maintain the switching valves (20a, 20b) of the brake circuits (12a, 12b) in a closed state during the opening time.

3. A brake system for a vehicle equipped with the control device (10) according to claim 1 or 2, A brake system for a vehicle, having at least the brake circuits (12a, 12b) connected to the master brake cylinder (14) of the brake system, the brake circuits (12a, 12b) comprising a liquid reservoir (16a, 16b) and high-pressure switching valves (18a, 18b) controllable by the electronic circuit device (26) of the control device (10), the brake circuits (12a, 12b) further comprising switching valves (20a, 20b) and the single wheel outlet valve and / or the plurality of wheel outlet valves (22a, 22b, 24a, 24b), the switching valves (20a, 20b), the single wheel outlet valve and / or the plurality of wheel outlet valves (22a, 22b, 24a, 24b) controllable by the electronic circuit device (26).

4. The brake system according to claim 3, wherein the single wheel outlet valve or the plurality of wheel outlet valves (22a, 22b, 24a, 24b) each has only one filter (23a, 23b, 25a, 25b) for the transfer of brake fluid from the wheel brake cylinders (28a, 28b, 30a, 30b) arranged in correspondence to the respective valve (22a, 22b, 24a, 24b) to the liquid reservoir (16a, 16b).

5. The brake system according to claim 3, wherein the single wheel outlet valve or the plurality of wheel outlet valves (22a, 22b, 24a, 24b) are filterless in order to move brake fluid from the liquid reservoir through their respective wheel outlet valves.

6. The brake circuit (12a, 12b) has a first wheel outlet valve (22a, 22b) and a second wheel outlet valve (24a, 24b) as its wheel outlet valve (22a, 22b, 24a, 24b), and the first conduit section (32a, 32b) of the brake circuit (12a, 12b) that opens to the master brake cylinder (14) branches to the switching valve (20a, 20b) and the high-pressure switching valve (18a, 18b), and the brake circuit (12a, 1 The second conduit section (34a, 34b) of 2b) branches into a first wheel inlet valve (36a, 36b) and a second wheel inlet valve (38a, 38b), and the first wheel brake cylinder (28a, 28b) is connected to or can be connected to the third conduit section (40a, 40b) of the brake circuit (12a, 12b), which branches into the first wheel inlet valve (36a, 36b) and the first wheel outlet valve (22a, 22b), and the second wheel brake cylinder (30a, 30b) However, the fourth conduit section (42a, 42b) of the brake circuit (12a, 12b), which branches to the second wheel inlet valve (38a, 38b) and the second wheel outlet valve (24a, 24b), is connected to or connectable to the fifth conduit section (46a, 46b) of the brake circuit (12a, 12b), which opens to the suction side of the pump device (44a, 44b) of the brake circuit (12a, 12b), and the first wheel outlet valve (22a, 22b) and the second wheel outlet valve (24a The brake system according to claim 3, wherein the brake circuit (12a, 12b) is branched into (12a, 12b), the liquid reservoir (16a, 16b) is connected to the fifth pipeline section (46a, 46b), the sixth pipeline section (48a, 48b) of the brake circuit (12a, 12b) opens to the discharge side of the pump device (44a, 44b), the seventh pipeline section (50a, 50b) of the brake circuit (12a, 12b) opens to the fifth pipeline section (46a, 46b), and opens to the high-pressure switching valve (18a, 18b).

7. A method for at least partially emptying the fluid reservoirs (16a, 16b) of a vehicle's brake system, A method comprising the steps of controlling the high-pressure switching valves (18a, 18b) of the brake circuit (12a, 12b) of the brake system, which is equipped with the liquid reservoirs (16a, 16b), to be at least partially open for a preset or specified opening time, thereby allowing brake fluid to flow into the master brake cylinder (14) of the brake system, which is connected to the brake circuit (12a, 12b), via the high-pressure switching valves (18a, 18b) that are at least partially open from the liquid reservoirs (16a, 16b) during the opening time (S4), A method for at least partially emptying the fluid reservoirs (16a, 16b) of a vehicle's brake system, characterized by controlling the single wheel outlet valve of the brake circuit and / or all wheel outlet valves (22a, 22b, 24a, 24b) of the brake circuit (12a, 12b) to be closed during the opening time, thereby maintaining a state in which the movement of brake fluid from the fluid reservoirs (16a, 16b) into the master brake cylinder (14) without passing through the high-pressure switching valves (18a, 18b) is blocked (S5).

8. The method according to claim 7, wherein the switching valves (20a, 20b) of the brake circuits (12a, 12b) are controlled or maintained in a closed state during the opening time (S5b).

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