Method and device for operating brake system of motor vehicle

Abstract

The invention relates to a method for operating a brake system (14) of a motor vehicle (10) comprising a first electronic control unit (34) and a second electronic control unit (36), the first control unit (34) being designed to actuate the brake system (14) and the second control unit (36) being designed to control at least one driving stabilization function / at least one driving stabilization program. First, a collision of the motor vehicle (10) is detected. Then detecting at least one physical value associated with the detected collision and associated with the collision; and comparing the physical value with a preset threshold value. Based on this, a braking process is introduced by means of the first electronic control unit (34) and / or the second electronic control unit (36). The invention also relates to a device for carrying out the method.

Description

Field of the Invention

[0001] The present invention relates to a method and a device for operating a braking system of a motor vehicle. Background Art

[0002] Motor vehicles usually have a central control device for controlling all driving functions. This includes the control of the drive, as well as the control of auxiliary functions and driving stability functions.

[0003] Furthermore, for reasons of robustness and usability, it is common to additionally provide a brake controller with which the braking system can be actuated.

[0004] In normal operation, i.e., in regular driving situations that do not constitute extreme cases, the brake controller receives a brake command in the form of a signal here and forwards this brake command to the driving function controller. The driving function controller adjusts this brake command accordingly, if necessary, taking into account the driving stability function. For this purpose, the controller calls a plurality of sensors in order to detect, for example, the current steering angle, lateral acceleration, yaw rate, yaw acceleration, and wheel speed, and adjusts the brake command accordingly based on these values. Subsequently, the brake command modified if necessary is transmitted back to the brake controller. The brake controller controls the braking system and thus initiates the braking process.

[0005] When a motor vehicle collides, the motor vehicle automatically brakes by means of the brake controller. This is necessary to prevent further collisions because, for example, the vehicle is no longer steerable, the driver loses consciousness or is startled, or the steering wheel cannot be operated due to the triggering of the airbag. In a general sense, "collision" should be understood as an accident, so that the collision can be, for example, a frontal collision, a rear-end collision, or a side collision, or a vehicle rollover, or any other accidental contact of the vehicle with an object that may cause damage to the motor vehicle.

[0006] Therefore, in the event of a collision, there may not be a brake command specified by the driver. Rather, the brake controller specifies this brake command and forwards this brake command to the driving function controller as described in the above paragraph.

[0007] However, here if the communication between the controllers is disturbed due to an accident, or if there are missing (reliable) values for the driving function controller to ensure the driving stability function of the vehicle, for example because a sensor is damaged, or the front axle is damaged due to an accident so that the steering angle cannot be determined, then the brake controller only recognizes this situation after a certain time and switches the regulation only to the brake controller.

[0008] Alternatively, the brake controller can forward the brake command directly as a brake request to the brake system without first forwarding the brake command to the driving function controller. However, this would cause the automatic braking after each accident to occur without considering the driving stability function, which may have an adverse effect on braking. Summary of the Invention

[0009] Starting from this, the object of the present invention is to provide a method for operating the brake system of a motor vehicle, which ensures better braking of the motor vehicle after a collision of the motor vehicle.

[0010] According to the present invention, this object is solved by a method for operating the brake system of a motor vehicle, the vehicle comprising a first electronic controller and a second electronic controller, wherein the first controller is designed to operate the brake system, and the second controller is designed to control at least one driving stability function, the method comprising the following steps:

[0011] a) Identifying a collision of the motor vehicle;

[0012] b) Detecting at least one physical value that is assigned to and related to the identified collision;

[0013] c) Comparing the detected physical value with a preset limit value; and

[0014] d) If the detected physical value is below the limit value, initiating a braking process by means of the first electronic controller and controlling at least one driving stability function by means of the second electronic controller; or if the detected physical value reaches or exceeds the limit value, initiating a braking process by means of the first electronic controller and not controlling at least one driving stability function by means of the second electronic controller.

[0015] The basic idea of the present invention is to determine whether the collision involves a "minor" or "severe" accident of the motor vehicle according to the physical value measured in step b). For this purpose, in step c), the physical value is compared with the limit value.

[0016] If the physical value or its absolute value is below the preset limit value, it can be inferred that the collision involves a "minor" accident. From this, it can be deduced that even after the collision, there is a stable connection between the first controller and the second controller, and all the measured values required for the second controller to implement the driving stability function are available. In addition, it can also be inferred that the vehicle - especially the chassis - is still functioning properly, so that the vehicle remains controllable.

[0017] Accordingly, in step d), a braking process is initiated by means of the first electronic controller, and the driving stability function is taken over by the second electronic controller.

[0018] However, if the physical value or its absolute value reaches or exceeds a preset limit value, this is classified as a "severe" accident. From this, it can be deduced that the connection between the first controller and the second controller may have been interrupted or disturbed. In addition, the sensors used to implement the driving stability function may also be damaged, so that there is no value or only unreasonable values for the second electronic controller, for example, because the front axle steering device is damaged and there is an unreasonable steering angle. In addition, it can also be inferred that the vehicle can only be maneuvered with limitations and, for example, the chassis is damaged.

[0019] In this case, a braking process is initiated by means of the first electronic controller. However, the driving stability function of the second electronic controller is not manipulated, so that the time during which the first controller attempts to contact the no longer connected or malfunctioning second controller is not lost.

[0020] The at least one physical value can be the average acceleration and / or the maximum acceleration during a collision, and / or a value related to the collision impulse generated in the accident.

[0021] Both the acceleration and the collision impulse allow an unambiguous inference of the "intensity" of the collision. In addition, there are usually sensors in a motor vehicle that detect these values during a collision in order to determine, for example, whether an airbag needs to be triggered.

[0022] In addition, the physical value can also be the pressure measured in a hose extending along the vehicle body. When the vehicle collides, the hose deforms according to the collision and a pressure is generated inside the hose, which can be measured and the "intensity" of the collision can also be estimated based on this pressure. Such hoses are usually located in the vehicle bumper.

[0023] Preferably, the preset limit value can be determined such that when it is below the limit value in step c), the airbag of the motor vehicle is not triggered, while when it reaches or exceeds the limit value, at least one airbag is triggered.

[0024] Therefore, after a "minor" accident and when the airbag has not been triggered, the driver can still continue to drive the motor vehicle. If a "severe" accident is involved (in which the vehicle can no longer be maneuvered anyway), then at least one airbag is additionally triggered. Here, it doesn't matter that the driver may no longer be able to operate the steering wheel due to the triggered airbag.

[0025] Furthermore, the limit value can be determined such that when it is below the limit value in step c), the second electronic controller can control the driving stability function based on the steering angle and / or wheel speed and / or lateral acceleration and / or yaw rate and / or yaw moment present in steps c) and d).

[0026] Therefore, the limit value is selected such that the driving stability function can continue to be implemented based on these values, because the corresponding sensors are still working properly and, despite a "minor" accident, at least approximately function without restriction. Accordingly, the driving stability function is still ensured by means of the second electronic controller.

[0027] Preferably, the braking process introduced in step d) is carried out until the motor vehicle stops. This can prevent a startled driver from continuing to move the motor vehicle after an accident, or can prevent subsequent accidents, because for example the driver loses consciousness and cannot actively drive the vehicle or the vehicle can no longer be steered.

[0028] Furthermore, the braking process introduced in step d) is carried out immediately after it is recognized in step a) that the motor vehicle has collided.

[0029] According to a variant, when the limit value is exceeded in step c), the driving stability function can be controlled in step d) by means of the first electronic controller. Thus, even when the limit value is exceeded, it is ensured that the braking process introduced in step d) is carried out taking into account the stabilization of the driving behavior.

[0030] Here, compared to the driving stability function of the second controller, the driving stability function of the first electronic controller can be reduced in its scope and only the wheel speed of the motor vehicle is called for control.

[0031] Accordingly, the first electronic controller generates a driving stability function that is significantly simpler and easier than the driving stability function of the second controller. This has the following advantage: when the braking process is introduced, the motor vehicle can still be stabilized accordingly, and this driving stability function only has to call the wheel speed of one wheel or the wheel speeds of multiple wheels of the motor vehicle, without having to call other measured values.

[0032] It is also conceivable here to stabilize the vehicle only based on the available and reasonable wheel speeds. For example, if the motor vehicle has experienced a frontal collision and the front axle has been severely damaged due to this frontal collision, the driving stability function can always still call the wheel speeds of the rear wheels in order to stabilize the motor vehicle.

[0033] The above-mentioned task is also solved by a device for performing the method according to the invention, the device comprising: a braking system; a sensor device for detecting the steering angle and / or wheel speed and / or lateral acceleration and / or yaw rate and / or yaw moment; a collision sensor device for detecting a collision of a motor vehicle; and a sensor for detecting at least one physical value present in and related to the detected collision; a first electronic controller, the first electronic controller being configured to continuously query whether a collision exists, and if below a threshold value, directly or indirectly via a second electronic controller control the braking system based on the at least one physical value to achieve vehicle stability; a second electronic controller being configured to control at least one driving stability function during the braking process.

[0034] Regarding the advantages achieved, reference is made to the above description.

[0035] The collision sensor device for detecting a collision of a motor vehicle may have an acceleration collision sensor and / or a sensor for detecting a value related to the collision impulse generated in an accident.

[0036] Here, the sensor may be a pressure sensor for detecting the pressure in a hose extending along the body of the motor vehicle. According to the above description, the hose extends in particular along the bumper of the vehicle.

[0037] Regarding the other advantages resulting therefrom, reference is likewise made to the above description. Description of the Drawings

[0038] The present invention will be described below with the aid of an embodiment, which is shown in the drawings. Shown in these drawings are:

[0039] Figure 1 A motor vehicle is schematically shown with a device according to the invention;

[0040] Figure 2 Shown in detail is Figure 1 the device according to the invention in a first operating mode; and

[0041] Figure 3 Shown is Figure 2 the device according to the invention in a second operating mode. Detailed Description of the Invention

[0042] Figure 1 Shown is a motor vehicle 10, which has a device 12, the device comprising a braking system 14, a sensor device 16 and a collision sensor device 18.

[0043] The sensor device 16 is for detecting the steering angle and / or wheel speed and / or lateral acceleration and / or straightness and / or yaw moment acting on the motor vehicle 10.

[0044] The collision sensor device 18 is used to detect a collision of the motor vehicle 10. In a general sense, "collision" should be understood as an accident, so that the collision can be, for example, a frontal collision, a rear-end collision or a side collision, or any other accidental contact of the vehicle with an object that may cause damage to the motor vehicle.

[0045] For this purpose, the collision sensor device 18 has sensors 22, and at least one physical value present in and related to the detected collision is detected by means of these sensors. The sensors 22 are acceleration collision sensors 24 and / or sensors 26 for detecting a value related to a collision impulse.

[0046] These sensors 26 are present, for example, in the form of pressure sensors and are associated with hoses 28 extending respectively in the bumpers 32 of the motor vehicle along the vehicle body 30.

[0047] Furthermore, the device 12 includes a first electronic controller 34 and a second electronic controller 36.

[0048] The first controller 34 is configured in the form of a brake controller, while the second electronic controller 36 is configured as a driving function controller and can in particular perform at least one driving stability function during a braking process.

[0049] The operation of the braking system 14 of the motor vehicle 10 will be described below with the aid of Figure 2 and Figure 3 The operation of the braking system 14 of the motor vehicle 10 will be described below with the aid of

[0050] If a braking process is initiated during normal operation, the first electronic controller 34 receives a braking command at the signal input 38. This braking command is forwarded via the signal line 40 to the second electronic controller 36. The second electronic controller here performs at least one driving stability function if necessary and adjusts the braking command if necessary so that the vehicle still has a stable driving behavior during the braking process. Here, the second electronic controller 36 calls up the measured values of the sensor device 16.

[0051] The braking command, modified if necessary, is now transmitted back from the second controller 36 to the first electronic controller 34 via the signal line 42. This first electronic controller in turn controls the braking system 14 so that a braking process is initiated based on the specified braking command.

[0052] When the motor vehicle 10 experiences a collision, this is recognized by the sensors. This is achieved by means of the collision sensor device 18, which is able to determine whether a collision exists by means of the sensors 22, 24, 26.

[0053] The first electronic controller 34 is hereby set such that the first electronic controller continuously queries for the presence of a collision.

[0054] Alternatively, the first electronic controller can also be actively informed, for example via the signal input 38 by the collision sensor device 18, that a collision has been recognized.

[0055] Furthermore, at least one physical value assigned to and related to the recognized collision is detected. This physical value is also detected by the collision sensor device 18.

[0056] For example, this physical value is here the average acceleration and / or the maximum acceleration during the collision, which are detected by the acceleration collision sensor 24.

[0057] Alternatively or additionally, the at least one physical value can also be a value related to the collision impulse generated by the collision of the motor vehicle 10. For example, this collision impulse is the pressure in the hose 28, which is detected by the sensor 26 implemented as a pressure sensor.

[0058] Subsequently, the at least one physical value is compared with a preset braking value.

[0059] This comparison can either be carried out by the first electronic controller 34 or can also have been carried out beforehand such that the first electronic controller 34 only receives via the signal line 38 the information whether the physical value is below a preset limit value or whether the physical value has reached or even exceeded the limit value.

[0060] Thus, the physical value provides a basis for the "intensity" of the collision of the motor vehicle 10. The limit value is a threshold value for classifying the collisions occurring in the motor vehicle based on the physical value. Since the physical value is related to the collision, the "intensity" of the collision directly affects this physical value. The comparison of the physical value with the preset limit value classifies the collision as a "minor" collision when the physical value or its absolute value is below the preset limit value and classifies the collision as a "severe" collision when the physical value or its absolute value has reached or even exceeded the limit value.

[0061] It can be envisaged here that the preset limit value is selected such that when the physical value is below the limit value, the airbag of the vehicle is not triggered, so that in the event of a "minor collision", the driver still has access to the steering wheel and can operate the vehicle; while when the limit value is reached and exceeded, at least one airbag is triggered.

[0062] The following should first be explained with the aid of Figure 2 the further operation for the case where the physical value is below the limit value.

[0063] Here, in the next step, the braking process is automatically initiated by means of the first electronic controller 34, where the first electronic controller forwards the braking command to the second electronic controller 36 via a signal line 40, similar to normal operation. The second electronic controller controls at least one driving stability function based on the measured values detected by the sensor device 16. The driving stability function is based at least on the steering angle and / or wheel speed and / or lateral acceleration and / or yaw rate and / or yaw moment present during or after a collision.

[0064] Subsequently, this braking command, adjusted if necessary, is transmitted back to the first controller 34 via the signal line 42, and the first electronic controller 34 actuates the braking system 14 to initiate an automatic braking process after a collision.

[0065] The initiated braking process is carried out until the vehicle comes to a stop. This prevents the vehicle from moving uncontrollably after a collision and, if possible, prevents other accidental collisions.

[0066] Now, the following should be explained with the help of Figure 3 the further operation of the braking system 14 when the physical value is equal to or exceeds a preset limit value.

[0067] As already explained in the previous paragraph, in this case, it can be inferred that a "severe collision" is involved. Therefore, it is not ensured that the first electronic controller 34 can always still communicate with the second electronic controller 36 via the signal lines 40, 42.

[0068] In addition, independently of this, there is also the possibility that the sensor device 16 has been damaged, providing unreasonable measured values, or providing measured values according to which the driving stability function cannot be achieved. The latter is, for example, the case where the front axle of the motor vehicle 10 is damaged and a very large steering angle is determined (the steering angle also varies strongly between the wheels, so that a reliable driving stability function can no longer be achieved).

[0069] For this reason, when the physical value reaches or exceeds the limit value, an automatic braking process is initiated only by means of the first electronic controller 34, and the driving stability function is not achieved by means of the second electronic controller 36 here. This ensures that in the event of a "severe" collision, the vehicle 10 is still reliably braked, and the first electronic controller 34 does not attempt to contact the second electronic controller 36 here.

[0070] Similar to the above, for further steps, it also applies that the braking process occurs until the motor vehicle 10 comes to a stop, and the braking process may be initiated with a time delay.

[0071] Furthermore, it is conceivable that the first electronic controller 34 itself implements a driving stability function. Compared to the driving stability function of the second controller 36 described above, this driving stability function can be reduced in its scope and, for control purposes, can only call the wheel speeds of the motor vehicle 10. This is particularly suitable when reasonable wheel speeds are still measured at least on one axle of the motor vehicle 10, for example when the vehicle is damaged only at the front or at the rear of the vehicle.

Claims

1. A method for operating a braking system (14) of a motor vehicle (10), the motor vehicle comprising a first electronic controller (34) and a second electronic controller (36), wherein, The first controller (34) is designed to operate the braking system (14), and the second controller (36) is designed to control at least one driving stability function. The method includes the following steps: a) Identifying a collision of the motor vehicle (10); b) Detecting at least one physical value that is assigned to and related to the identified collision; c) Comparing the detected physical value with a preset limit value; and d) If the detected physical value is below the limit value, initiating a braking process by means of the first electronic controller (34) and controlling at least one driving stability function by means of the second electronic controller (36); or if the detected physical value reaches or exceeds the limit value, initiating a braking process by means of the first electronic controller (34) and not controlling at least one driving stability function by means of the second electronic controller (36).

2. The method according to claim 1, characterized in that, The at least one physical value is the average acceleration and / or maximum acceleration during the collision, and / or a value related to the collision impulse generated in the accident.

3. The method according to claim 1 or 2, characterized in that, The physical value is the pressure measured in a hose (28) extending along the vehicle body (30) of the vehicle (10).

4. The method according to any one of the preceding claims, characterized in that, The preset limit value is determined such that when it is below the limit value in step c), the airbag of the motor vehicle (10) is not triggered, and when it reaches or exceeds the limit value, at least one airbag is triggered.

5. The method according to any one of the preceding claims, characterized in that, The limit value is determined such that when it is below the limit value in step c), the second electronic controller (36) controls the driving stability function based on the steering angle and / or wheel speed and / or lateral acceleration and / or yaw rate and / or yaw moment present in steps c) and d).

6. The method according to any one of the preceding claims, characterized in that, The braking process initiated in step d) is carried out until the motor vehicle (10) stops.

7. The method according to any one of the preceding claims, characterized in that, When the limit value is exceeded in step c), the driving stability function is controlled by means of the first electronic controller (34) in step d).

8. The method according to claim 7, characterized in that, Compared with the driving stability function of the second controller (36), the driving stability function of the first electronic controller (34) is reduced in its scope, and only the wheel speed of the motor vehicle (10) is called for control.

9. An apparatus for performing the method according to any one of the preceding claims, the apparatus comprising: A braking system (14); a sensor device (16) for detecting the steering angle and / or wheel speed and / or lateral acceleration and / or yaw rate and / or yaw moment; a collision sensor device (18) for detecting a collision of the motor vehicle (10); and a sensor (22) for detecting at least one physical value present in and related to the detected collision; a first electronic controller (34), which is arranged to continuously query for the presence of a collision and, if below the limit value, operate the braking system (14) directly or indirectly via the second electronic controller (36) based on the at least one physical value to achieve vehicle stability; a second electronic controller, which is arranged to control at least one driving stability function during the braking process.

10. The apparatus according to claim 9, characterized in that, The collision sensor device (18) for detecting a collision of the motor vehicle (10) has an acceleration collision sensor (24) and / or a sensor (26) for detecting a value related to the collision impulse generated in the accident.

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