Method for filling a brake system of a vehicle and controller for a brake system of a vehicle

Abstract

The invention relates to a method for filling a brake system (100) of a vehicle (104), in which a filling device (106) is connected to the brake system (100) and a control unit (102) of the brake system (100) is activated, in which the control unit (102) monitors a pressure signal (136) of a pressure sensor (134) of the brake system (100) in order to detect a filling process (200) carried out by the filling device (106), the controller (102) activates a valve (128) of the brake system (100) in response to identifying a start time (212) of the filling process (200), and the controller (102) deactivates the valve (128) in response to identifying an end time (218) of the filling process (200).

Description

Technical Field

[0001] The invention relates to a method for filling a brake system of a vehicle, a control unit for a brake system of a vehicle and a corresponding computer program product. Background Art

[0002] During the manufacture of the vehicle, the brake system of the vehicle can be filled for the first time. For this purpose, for example, a filling head of a filling device can be placed on the reservoir of the master brake cylinder. To avoid air locks, air can be sucked out of the brake system via the filling head and brake fluid can be injected into the air-free brake system. Brake fluid can be injected into the brake system by means of overpressure.

[0003] If the brake system comprises, for example, ABS or ESP, it has a secondary circuit which is separated from the brake circuit of the brake system by a valve which is closed when there is no current. Since the valve is closed, air cannot be sucked out of the secondary circuit and brake fluid cannot enter the secondary circuit during filling. Therefore, the secondary circuit can be prefilled with brake fluid at a separate filling station before installation in the vehicle. Since the valve is closed, the brake fluid cannot escape.

[0004] Alternatively, the filling device can be controlled and actively open the valve during filling to connect the secondary circuit to the brake circuit. For this purpose, the filling device can be connected to the data bus of the vehicle via an adapter, thereby sending a control command to open the valve to the brake system. Summary of the invention

[0005] Against this background, a method for filling a brake system of a vehicle, a control unit for a brake system of a vehicle and a corresponding computer program product are proposed with the solution proposed herein according to the independent claims. Advantageous developments and improvements of the solution proposed herein are given in the description and described in the dependent claims.

[0006] The filling process has a characteristic pressure curve due to the generation of, for example, a strong negative pressure or vacuum in the brake system, the subsequent pressure increase to fill the brake fluid and the final pressure reduction to ambient pressure. The pressure curve may be different for different brake system types, but the pressure curve for each brake system type is known.

[0007] In the solution proposed here, at least one controller of the brake system is activated during the filling process. At least one pressure sensor of the brake system is connected to the controller and communicates with it. The pressure sensor is used to detect the pressure curve of the filling process. At least characteristic points of the expected pressure curve of the brake system are stored in the controller. The controller evaluates the pressure information provided by the pressure sensor and compares it with the stored information to identify the filling process. The controller is also connected to the valve drive of the brake system. When the filling process is detected, the controller controls the valve drive required for connecting the secondary circuit and the brake circuit and thus connects the secondary circuit to the brake circuit.

[0008] With the solution proposed here, the data connection between the filling device and the brake system is superfluous and can be omitted. Since the data connection is omitted, costs and time can be saved. In particular, no adapter is required to connect the filling device to the vehicle's data bus. The insertion and removal of the adapter is also omitted. The time requirement for reaching the interface of the data bus twice, which is otherwise required, is thus also omitted.

[0009] Since the data line is omitted, there is no need to coordinate the communication protocol between the filling device and the vehicle. Therefore, the development cost of the filling device and the controller software can be reduced.

[0010] A method for filling a brake system of a vehicle is proposed, wherein a filling device is connected to the brake system and a controller of the brake system is activated, wherein the controller monitors a pressure signal of a pressure sensor of the brake system in order to identify a filling process performed by the filling device, wherein the controller activates a valve of the brake system in response to identifying the start time of the filling process, and the controller deactivates the valve in response to identifying the end time of the filling process.

[0011] The idea of ​​the embodiments of the present invention can first be regarded as being based on the ideas and recognition described below.

[0012] The brake system can be dry-assembled on the vehicle. In order to bring the brake system into a functional state, it needs to be initially filled with brake fluid. This filling should be carried out in a bubble-free manner. The filling process can be carried out from outside the vehicle using a filling device. The filling process can have a vacuum phase and a pressure phase. In the vacuum phase, air can be removed from the brake system, i.e. the brake system can be emptied. In the pressure phase, the brake system can be filled with brake fluid. The filling process can be integrated into the production line of the vehicle as an assembly step. The filling process can be carried out during the production of the vehicle. For filling, the filling head of the filling device can be placed on the master brake cylinder, more precisely, on the reservoir of the master brake cylinder and connected in a pressure-tight manner. The filling head can be connected to the filling device via a hose. The filling device can, for example, have a vacuum pump and a pressure pump.

[0013] The braking system may have two separate braking circuits and a plurality of secondary circuits. At least one secondary circuit may be used to regulate the brake pressure in the braking circuit. A plurality of valves may be arranged between the respective braking circuits and the secondary circuits. These valves may be controlled by one or more controllers of the braking system. These valves may be arranged in a valve block of the braking system. The secondary circuit may extend between the valves in the valve block. The valves may be closed, for example, by a return spring in the absence of current. One or more controllers may be connected to the valve block. In order to open the valve, a control signal for a valve drive of the valve may be required. The control signal may be generated by the at least one controller. The controller may be referred to as a brake regulation controller and may control, for example, valves for the ABS and / or ESP of the vehicle during operation of the vehicle.

[0014] The controller can be operated in manufacturing mode to fill the brake system. The manufacturing mode can be deactivated after filling. Alternatively, the manufacturing mode can be deactivated at the end of the production line.

[0015] The controller can be activated by supplying power. For this purpose, for example, a battery voltage can be connected to a connection of the controller. The battery voltage can be provided by a cable harness of the vehicle. Alternatively, the controller can be supplied with power separately, for example, via an adapter or a clip. The battery voltage can be supplied by the battery of the vehicle or by an external energy source, such as a power supply. Likewise, the battery voltage can be supplied by a traction voltage of a traction battery of the vehicle via a voltage converter. Alternatively, the controller can be supplied with power via a filling head. An additional signal may be required for activation. This signal can be referred to as a wake-up signal or ignition, for example.

[0016] By activating the controller, the pressure sensor of the brake system can be energized. When the pressure sensor is energized, it can detect the pressure in the brake system and reflect it in the pressure signal. When the controller is activated, a pressure reference value can be stored which reflects the ambient pressure. The pressure sensor can be used in particular for detecting overpressures. The pressure sensor can, for example, have an operating range of from 1 bar to several hundred bar. Negative pressures can lie outside this operating range but are also reflected in the pressure signal. Due to the larger operating range, negative pressures can be reflected in the pressure signal with less accuracy.

[0017] The start and / or end of the filling process can be characterized by a characteristic pressure change. For example, the start and / or end can be detected by observing the curve of the pressure signal and / or by reaching a stored threshold value. When the valve is activated, the valve can be continuously switched by its valve drive. When deactivated, the valve drive can be stopped and the valve can be switched to a blocked state by its return spring.

[0018] The controller can use the pressure signal to identify the vacuum phase and the pressure phase. In the vacuum phase, the valve can be activated or switched to an open state to evacuate the secondary circuit. At the end of the pressure phase, the valve can be deactivated or switched to a blocked state. For example, the negative pressure in the brake system reflected in the pressure signal can be identified to identify the vacuum phase. In this case, the vacuum phase may have already begun before the pressure sensor can reflect the negative pressure in the pressure signal. Due to the negative pressure already present in the brake circuit, the secondary circuit can be emptied particularly quickly. The vacuum phase can also be followed by a preceding preparation phase. The preparation phase can have a characteristic pressure curve. The controller can recognize the end of the preparation phase and recognize the beginning of the vacuum phase after the end of the preparation phase.

[0019] After the vacuum phase has been detected, the valve can be activated with a time delay. This means that the valve can be activated only after a strong negative pressure has likely built up in the brake circuit. This allows the secondary circuit to be emptied particularly quickly.

[0020] After the filling process has ended, the controller can activate the pump of the brake system to empty at least one low-pressure reservoir of the brake system. The brake system can have at least one low-pressure reservoir. In particular, the brake system can have a low-pressure reservoir in each brake circuit. During normal operation of the brake system, brake fluid can be temporarily stored in the low-pressure reservoir by opening at least one valve to adjust the brake pressure in the brake circuit. The brake fluid can then be conveyed back from the low-pressure reservoir into the brake circuit by the pump of the brake system. The brake system can have a pump for each low-pressure reservoir. The low-pressure reservoir and the pump can be arranged in a valve block.

[0021] After the filling process is completed, the filling device can suck out excess brake fluid from the reservoir of the brake system in order to set a predefined fluid level in the reservoir. This process can be called balancing of the brake system. After the pressure filling, there is excess brake fluid in the at least one low-pressure reservoir. The pump can convey the brake fluid from the low-pressure reservoir to the reservoir. The pump can be activated for a predefined duration. In particular, the controller can control the drive motor of the pump. The drive motor can be coupled to a plurality of pumps. After deactivating the pump, the filling of the brake system can be completed.

[0022] Before the filling process, the filling device can perform a leak test of the brake system and apply pressure to the brake system. The controller can use the pressure signal to identify the leak test. For the leak test, air can be pumped into the brake system to increase the pressure. The pressure can be maintained during the duration of the test and monitored by the filling device. If the pressure drops by no more than the pressure tolerance during the test duration, the brake system is considered to be leak-tight. After the test duration, the air can be exhausted from the brake system again. After the leak test, the brake system may be filled with ambient pressure. The leak test can be part of a preparation phase. The controller can recognize the start of the filling process at the end of the leak test. During the leak test, the valve can be deactivated.

[0023] The filling process can be recorded in a non-volatile memory of the controller. The non-volatile memory can be, for example, an EEPROM. The non-volatile memory can have an additional storage area to record the filling process. The storage area can be called a filling byte. The storage area can store different values. During the filling process, the progress of the filling process can be recorded in the memory by different values. The previous and / or subsequent steps can also be recorded. After the end of a predefined phase of the filling process, the value of the filling byte can be set to a predefined value. The filling byte value can be increased step by step, or more precisely, increased synchronously with the phases of the filling process. In addition, at the end of the filling process, the error entry about the lack of brake fluid can be deleted from the error memory of the controller. The manufacturing mode of the controller can also be deactivated at the end of the filling process.

[0024] The controller can alternately open and close the valve of the first brake circuit of the brake system and the valve of the second brake circuit of the brake system. The valve can be used for pulsed control. Continuous operation is not possible. Repeated opening and closing can prevent overloading of the valve drive. Possible residual air bubbles can be discharged by the pressure wave formed.

[0025] The method is preferably computer-implemented and can be implemented, for example, in the form of software or hardware or in the form of a mixture of software and hardware, for example in a controller.

[0026] The solution proposed here also provides a control unit for a brake system of a vehicle, wherein the control unit executes, controls or implements the steps of the variant of the method proposed here in a corresponding device.

[0027] The controller can be an electrical device having at least one computing unit for processing signals or data, at least one storage unit for storing signals or data, and at least one interface and / or communication interface embedded in a communication protocol for reading or outputting data. The computing unit can be, for example, a signal processor, a so-called system ASIC or a microcontroller for processing sensor signals and outputting data signals according to the sensor signals. The storage unit can be, for example, a flash memory, an EPROM or a magnetic storage unit. The interface can be a sensor interface for reading sensor signals from a sensor and / or an actuator interface for outputting data signals and / or control signals to an actuator. The communication interface can read or output data wirelessly and / or wiredly. The interface can also be a software module that is present on a microcontroller, for example, together with other software modules.

[0028] Likewise advantageous is a computer program product or computer program having a program code, which can be stored on a machine-readable carrier or storage medium, such as a semiconductor memory, a hard disk memory or an optical memory, and is used, in particular, to execute, implement and / or control the steps of a method according to any of the above-described embodiments when the program product or program is executed on a computer or device.

[0029] It should be noted that some possible features and advantages of the present invention are described herein with reference to different embodiments. Those skilled in the art will recognize that the features of the controller and the method can be combined, adjusted or exchanged in an appropriate manner to obtain other embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Embodiments of the present invention are described below with reference to the accompanying drawings, wherein neither the accompanying drawings nor the descriptions are interpreted as limiting the present invention.

[0031] Figure 1 shows a diagram of a braking system having a controller according to an embodiment; and

[0032] Figure 2 A diagram showing the flow of a filling process according to an embodiment is shown.

[0033] The figures are merely schematic and not to scale. Identical reference numerals denote identical or effectively identical features. DETAILED DESCRIPTION

[0034] Figure 1The diagram shows a brake system 100 with a controller 102 according to an embodiment during a filling process according to the solution proposed herein. When passing through a production line of a vehicle 104, the brake system 100 has been installed in a vehicle 104 in an unfilled, i.e. empty, state. The vehicle 104 has arrived at a filling device 106 on the production line for the first filling of brake fluid. The filling device 106 has a filling head 108 and is connected to the brake system 100 via the filling head 108. A negative pressure line and a pressure line leading to the filling device 106 are led out from the filling head 108. The negative pressure line is connected to the vacuum pump of the filling device 106. The pressure line is connected to the pressure pump of the filling device 106.

[0035] In order to carry out the filling process, the controller 102 is powered on to activate the controller. Here, the cable harness 110 of the vehicle 104 is connected to the battery 112 of the vehicle 104 and the controller 102 for powering. In addition, the ignition 114 of the vehicle 104 is activated here.

[0036] The brake system 100 has a master brake cylinder 116 with a reservoir 118. Leading from the master brake cylinder 110 are two separate brake circuits 120, which lead to two wheel brakes 122 of the vehicle 104, respectively. In a valve block 124 of the brake system 100, the brake system 100 has four secondary circuits 126. The secondary circuits 126 are separated from the brake circuits 120 by valves 128. The secondary circuits 126 are connected to two pumps 130 and two low-pressure reservoirs 132 of the brake system 100. When the valves 128 are closed, the secondary circuits 126 cannot be filled during the filling process.

[0037] A pressure sensor 134 is arranged in at least one of the brake circuits 120. The pressure sensor 134 is connected to the control unit 102. During the filling process, the pressure sensor 134 is energized by the control unit 102. The pressure sensor 134 indicates the pressure in the brake circuit 120 with a pressure signal 136. The activated control unit 102 monitors the pressure signal 136 to detect the filling process.

[0038] For the filling process, the filling head 108 is connected in a pressure-tight manner to the reservoir 118 of the brake system 100. During the filling process, a strong negative pressure is generated in the brake system 100 in order to remove as much air as possible from the brake system 100. In particular, at least a partial vacuum is drawn in the brake system 100 by a vacuum pump. The brake fluid is then pumped into the deaerated brake system 100 at an excess pressure.

[0039] A strong negative pressure is characteristic of the filling process. In normal operation, such a negative pressure does not occur in the brake system 100. The negative pressure is detected by the pressure sensor 134 and reflected in the pressure signal 136. In one embodiment, the controller 102 recognizes the filling process based on the characteristic negative pressure.

[0040] When the controller 102 detects a filling process, it activates the valve 128 to connect the secondary circuit 126 to the brake circuit 120. After the filling process, the controller 102 deactivates the valve 128 again.

[0041] Figure 2 A diagram of the flow of a filling process 200 of a brake system is shown based on a characteristic pressure curve 202 and various signal curves in the brake system. The pressure curve 202 is composed of Figure 1 The filling process 200 is generated in a filling device connected to the brake system. Before the filling process 200, the brake system is at ambient pressure and is empty, i.e. filled with air, and after the filling process 200, the brake system is at ambient pressure and filled with brake fluid. During the filling process 200, the pressure in the brake system changes characteristically.

[0042] Prior to the filling process 200, the controller of the brake system to be filled is activated. For this purpose, the battery voltage 204 is applied to the controller. By activating the controller, the controller can read the pressure signal 136 of the pressure sensor of the brake system. The pressure sensor detects the pressure curve 202 and reflects it in the pressure signal 136.

[0043] The pressure curve 202, or more precisely the curve of the pressure signal 136, is shown in a graph with the time t in seconds as the abscissa and the absolute pressure p in bar as the ordinate. The controller evaluates the pressure signal 136 in order to detect the filling process 200. In this case, the pressure signal 136 is compared in the controller with stored, expected values ​​p1, p2, p3, p4 of the pressure signal 136 and / or an expected curve of the pressure signal 136 in order to detect the filling process 200.

[0044] If the control unit detects filling process 200 , it controls predefined valves of the brake system via control signals 206 , so that during filling process 200 the secondary circuit of the brake system is also filled with brake fluid.

[0045] In one embodiment, an activation signal 208 , such as an ignition or wake-up command, is additionally sent before the filling process 200 begins in order to activate the controller.

[0046] In one embodiment, the controller alternately controls valves of a first brake circuit of the brake system and valves of a second brake circuit of the brake system during filling process 200. Thus, either the valves of the first brake circuit are open and the valves of the second brake circuit are closed, or the valves of the first brake circuit are closed and the valves of the second brake circuit are open.

[0047] In one exemplary embodiment, after detecting the start time 212 of the filling process 200 , the controller actuates the valve after a delay of the delay time 210 .

[0048] The filling process 200 has a vacuum phase 214 with negative pressure in the brake system and a pressure phase 216 with overpressure in the brake system. The negative pressure and overpressure are each maintained for a holding time in order to achieve a stable state of the brake system. In one embodiment, the negative pressure is reflected in the pressure signal 136, although the pressure sensor is used to detect the brake pressure during the braking process. However, since the negative pressure can be at most 1 bar lower than the ambient pressure, this negative pressure is several orders of magnitude lower than the brake pressure, which can be several hundred bar. When the pressure sensor reflects the negative pressure in the pressure signal 136, the start time 212 has already passed and the vacuum phase 214 has begun. Therefore, the controller immediately starts to actuate the valve after the vacuum phase 214 is detected.

[0049] During the end of the vacuum phase 214 and the beginning of the pressure phase 216, the controller controls the valve continuously. The valve is not actuated again until the end time 218 of the pressure phase 216 is detected. The pressure phase 216 is detected when the overpressure is greater than a threshold value p3. The end time 218 of the pressure phase 216 is detected when the overpressure is again less than a further threshold value p4. The further threshold value p4 is less than the threshold value p3 and is within the range of the ambient pressure.

[0050] In one exemplary embodiment, when the end time 218 of the filling process 200 is detected, the control unit actuates a pump motor of at least one pump of the brake system via a further control signal 206. Excess brake fluid is pumped out of at least one low-pressure reservoir of the brake system by means of the pump and can be sucked out by the filling device. This process can be referred to as balancing 220 of the brake system.

[0051] In one embodiment, the entire process includes a leak test 222 prior to the filling process 200. For this purpose, an overpressure is applied to the empty brake system via a filling head by introducing compressed air into the brake system. Here, a test pressure is set and maintained for a test duration before the overpressure subsides and the brake system returns to ambient pressure. If the test pressure does not remain approximately constant during the test duration, the brake system is identified as leaking and the filling process 200 is not started.

[0052] The leak test 222 is reflected in the pressure curve 202 and thus also in the pressure signal 136. In this case, the controller recognizes the leak test 222 based on the pressure in the brake system rising above the threshold value p1 and falling below the next threshold value p2 again after the test duration. In this case, the threshold value p2 is less than the first threshold value p1. In particular, the threshold value p2 is within the range of the ambient pressure.

[0053] When it falls below the threshold value p2 , the control unit detects the end of the leak test 222 and thus the start time 212 of the filling process 200 and subsequently actuates the valve.

[0054] In one embodiment, the progress of the filling process 200 is recorded in a non-volatile memory 224 of the controller. For this purpose, the value of a so-called filling byte 226 of the memory 224 is changed stepwise when different phases of the filling process 200 are detected.

[0055] In one exemplary embodiment, the identified start time 212 of the vacuum phase 214 , the start time 228 of the pressure phase 216 when it rises above the threshold value p3 , and the end time 218 of the pressure phase 216 when it falls below the threshold value p4 are recorded.

[0056] In one embodiment, the leak test 222 is also recorded in the memory 224. The start of the leak test 222 is recorded when rising above the threshold p1, and the end of the leak test 222 and the start time 212 of the vacuum phase 214 are recorded when falling below the threshold p2.

[0057] In one exemplary embodiment, the start of balancing 220 is recorded with activation of the pump motor at the time 218 of the drop below the threshold value p4, ie the end of the filling process 200. After deactivation of the pump motor, the completion of the entire process is recorded in the memory 224.

[0058] In one embodiment, after deactivating the pump motor, the error entry 230 “Brake not filled” in the memory 224 is deleted.

[0059] In one embodiment, changes can be made to memory 224 only when manufacturing mode 232 of the controller is activated.

[0060] The following summarizes the feasible design solutions of the present invention again, or presents the feasible design solutions of the present invention in slightly different wording.

[0061] A method for filling a vehicle brake system with a brake adjustment system without using a tester is proposed.

[0062] For dry vacuum filling of vehicle brake systems, all areas of the brake system should be dry, sealed and evacuable. However, due to the brake control system (such as ABS, The secondary circuits in brake control systems (such as brake control systems) are usually separated from the rest of the brake circuit by hydraulic actuators, so these areas can be pre-filled, or the actuators can be designed to open under vacuum, or the corresponding actuators can be controlled when the vacuum is filled.

[0063] The actuator is usually controlled by serial diagnostic communication with the brake control system during vacuum filling. In this case, the brake control system is powered on. Most OEMs (Original Equipment Manufacturers) control the actuator of the brake control system with the help of serial diagnostic communication during vacuum filling. Some OEMs use brake control systems with filled secondary circuits for various reasons.

[0064] By dispensing with serial communication in the case of vacuum filling without a tester, as proposed herein, additional costs for structural modifications of a brake control system or of an actuator with a filled secondary circuit can be saved. Furthermore, the development of a communication system (tester), which has been required to date, including communication software on the brake filling device, can be dispensed with. Furthermore, the processing time for contacting the tester with a communication interface in the vehicle, for example via an OBD2 plug connection, can be dispensed with on the OEM assembly line. Furthermore, structural adjustments to the brake control system, for example special pump elements or sealing rings, can be dispensed with. By dispensing with a separate secondary circuit filling, the required filling device and the correspondingly complex filling process can be dispensed with.

[0065] In the solution proposed in this paper, vacuum filling is automatically recognized in the OEM assembly plant by the software of the brake regulation system.

[0066] Since vacuum filling is characterized by a special pressure curve, this is used in the solution proposed in this article for automatic recognition by the software and hardware of the brake control system. The start of vacuum filling is automatically recognized based on the pressure sensor already in the brake control system and the required actuator control is performed. In addition, the corresponding progress information is written to the so-called "filling byte" in the non-volatile memory (EEPROM) in the controller of the brake control system. The initial content of the "filling byte" is the value "vacuum filling without tester is not performed". This value can be a numerical value between 0 and 6, where each numerical value represents the corresponding progress information. This function is limited to use in OEM manufacturers and can only be executed when the "manufacturing mode" in the brake control system is activated. For safety reasons, the "vacuum filling without tester" function is only executed when stationary (V<=2km / h).

[0067] In the vacuum-filled area of ​​the OEM assembly line, the vehicle and thus the brake control system are powered on. In this case, for example, a cable harness can be plugged into the brake control system and a low-voltage battery can be installed or a DC / DC converter can be activated. In addition, the ignition can be switched on, or the brake control system can be activated by a corresponding wake-up function in the control unit, for example by detecting active vehicle-bus communication. Due to the wake-up function in the control unit of the brake control system, only a standard voltage supply with battery voltage is required, for example via the clamp 30. This provides the OEM with further time and cost advantages, since the step of switching on the ignition by the worker on the production line is omitted.

[0068] In a first process step, the vehicle brakes are tested for leak tightness using compressed air with a typical pressure of 3 bar to 6 bar. The brake control software detects the pressure change, for example, by a relative pressure value p1 of greater than 2 bar at the pressure sensor of the brake control system and starts the "vacuum filling without tester" function. In order to save manufacturing time, the brake system only reaches the desired pressure briefly and then immediately reduces the pressure again. This brief pressure pulse is sufficient to trigger the "vacuum filling without tester" function. The start of the "vacuum filling without tester" function is recorded in the non-volatile memory (EEPROM) of the controller of the brake control system with the value "vacuum filling without tester start".

[0069] In a second process step, the entire brake system is evacuated after the leak test has been completed. The brake control software detects this pressure change, for example, by a relative pressure value p2 of 0±1 bar at the pressure sensor of the brake control system and starts the necessary actuation of the actuators of the brake control system after a defined delay time in order to evacuate and fill the secondary circuits in the brake control system. The "vacuum phase" process step is recorded in the non-volatile memory (EEPROM) of the control unit of the brake control system with the value "vacuum phase start" or after a defined delay time with the value "start actuation of actuators (valves)".

[0070] In the third process step, after the vacuum phase and the vacuum tightness test, the filling device switches to a filling phase with a typical filling pressure of 3 bar to 6 bar. The software in the brake control system recognizes this pressure change, for example, by a relative pressure p3 of more than 2 bar on the pressure sensor. The already ongoing control of the actuators of the brake control system is not changed, i.e. continues unchanged. The "filling phase" process step is recorded in the non-volatile memory (EEPROM) of the controller of the brake control system with the value "start of filling phase". From this stage onwards, regardless of whether there is a "manufacturing mode" in the brake control system, the "vacuum filling without tester" function will be blocked in the future and can no longer be executed.

[0071] In a fourth process step, after the filling phase has ended, the filling device switches to balancing, during which the excess volume in the brake fluid container is sucked out to the maximum permissible level. In this phase, the filling pressure decreases. The brake control software recognizes this pressure change, for example, by a relative pressure value p4 of 0±1 bar on the pressure sensor, ends the control of the actuator of the brake control system for filling the secondary circuit, and thereafter starts the required control of the actuator to empty the low-pressure reservoir in the brake control system. The "balancing" process step is recorded in the non-volatile memory (EEPROM) of the controller of the brake control system with the value "balancing". After the actuator control for emptying the low-pressure reservoir has ended, the value "vacuum filling without tester has been carried out" is recorded, and the error entry "brake not filled" in the brake control system is automatically reset.

[0072] Finally it should be pointed out that terms such as "having", "comprising" etc. do not exclude other elements or steps and terms such as "a" or "an" etc. do not exclude a plurality. Reference signs in the claims shall not be considered as limitations.

Claims

1. A method for filling a brake system (100) of a vehicle (104), wherein: A filling device (106) is connected to the brake system (100) and a controller (102) of the brake system (100) is activated, wherein the controller (102) monitors a pressure signal (136) of a pressure sensor (134) of the brake system (100) to identify a filling process (200) performed by the filling device (106), wherein the controller (102) activates a valve (128) of the brake system (100) in response to identifying a start time (212) of the filling process (200), and wherein the controller (102) deactivates the valve (128) in response to identifying an end time (218) of the filling process (200).

2. The method according to claim 1, wherein: The filling process (200) has a vacuum phase (214) and a pressure phase (216), wherein the filling device (106) evacuates the brake system (100) during the vacuum phase (214) and fills the brake fluid during the pressure phase (216), wherein the controller (102) uses the pressure signal (136) to identify the vacuum phase (214) and the pressure phase (216), wherein the valve (128) is activated during the vacuum phase (214) and is deactivated at the end (218) of the pressure phase (216).

3. The method according to claim 2, wherein: After the vacuum phase (214) is detected, the valve (128) is activated with a time delay.

4. A method according to any one of the preceding claims, wherein: After the filling process (200) is completed, the control unit (102) activates a pump (130) of the brake system (100) to empty at least one low-pressure accumulator (132) of the brake system (100).

5. A method according to any one of the preceding claims, wherein: The filling device (106) performs a leak test (222) of the brake system (100) and pressurizes the brake system (100) before the filling process (200), wherein the controller (102) uses the pressure signal (136) to identify the leak test (222).

6. A method according to any one of the preceding claims, wherein: The filling process (200) is recorded in a non-volatile memory (224) of the controller (102).

7. A method according to any one of the preceding claims, wherein: The controller (102) alternately opens and closes a valve (128) of a first brake circuit (120) of the brake system (100) and a valve (128) of a second brake circuit (120) of the brake system (100).

8. A controller (102) for a braking system (100) of a vehicle (104), wherein: The control unit (102) executes, implements and / or controls the method according to any of the preceding claims in a corresponding device.

9. A computer program product, which is configured to instruct a processor to execute, implement and / or control the method according to any one of claims 1 to 7 when the computer program product is executed.

10. A machine-readable storage medium having stored thereon a computer program product according to claim 9.

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