Method of operating a vehicle brake system, control device for a brake system, brake system

Abstract

The invention relates to a method for operating a brake system (1) of a vehicle (2), the brake system (1) having a first and a second actuator (3, 4) for generating a hydraulic pressure in the brake system (1), a first control device (5) configured to actuate the first actuator (3), and a second control device (6) configured to actuate the second actuator (4), wherein it is monitored whether a critical braking of the brake system (1) is taking place, wherein if a critical braking is detected, the first actuator (3) is actuated by the first control device (5) to generate a first hydraulic pressure for achieving a predefined emergency deceleration of the vehicle (2). The method according to the invention is distinguished in that if the deceleration achieved or achievable by the first actuator (3) is less than the predefined emergency deceleration, the second control device (6) is actuated by the first control device (5) to actuate the second actuator (4) for generating a second hydraulic pressure.

Description

Technical Field

[0001] The present invention relates to a method for a braking system for operating a vehicle, the braking system comprising: first and second actuators for generating hydraulic pressure in the braking system; a first control device configured to operate the first actuator; and a second control device configured to operate the second actuator; wherein the braking system is monitored for dangerous braking; wherein if dangerous braking is detected, the first actuator is operated by the first control device to generate a first hydraulic pressure for achieving a predetermined emergency deceleration of the vehicle.

[0002] Furthermore, the present invention also relates to: first and second control devices for a braking system; and a braking system for a vehicle. Background Technology

[0003] Methods, control devices, and braking systems of the type mentioned at the beginning are known from the prior art. In particular, it is known to assist the vehicle driver based on detected dangerous braking to achieve full deceleration of the vehicle. Here, upon identification of dangerous braking, full deceleration of the vehicle is initiated by the vehicle's auxiliary system, particularly hydraulic brake assist, until the vehicle comes to a stop. By activating the hydraulic brake assist, the predetermined emergency deceleration of the vehicle, particularly the maximum possible deceleration, is achieved as quickly as possible. To this end, the actuators of the vehicle's braking system (particularly the electromechanical brake booster of the electronic stability program or the hydraulic pump) are manipulated by the control device to generate hydraulic pressure in the braking system, thereby achieving the maximum possible deceleration of the vehicle. For this purpose, the braking pressure at the wheel brakes of the vehicle is specifically set such that these braking pressures are increased up to the adjustment range of the anti-lock braking system, that is, these braking pressures are increased up to the lock-up pressure of each wheel or the lock-up limit of each wheel. Summary of the Invention

[0004] The key feature of the method according to an embodiment of the invention is that if the deceleration achieved or achievable by the first actuator is less than a predetermined emergency deceleration, then the second control device is manipulated by the first control device to operate the second actuator to generate a second hydraulic pressure. By manipulating the second control device in this way by the first control device, the predetermined emergency deceleration of the vehicle is ensured at all times by means of the second actuator. Therefore, the second control device receives the requirements for assisting the first control device or for initiating dangerous braking. Furthermore, the second control device does not need to monitor whether the braking system is engaging dangerous braking; rather, this can be done by the first control device. Preferably, the second control device is part of the vehicle's electronic stability program or anti-lock braking system. Preferably, the first control device controls independently operable parts, particularly the electromechanical braking system. Preferably, the first control device obtains information about the achieved deceleration of the vehicle and / or the adjustment state of the anti-lock braking system, particularly the brake slip rate, from sensors, particularly those assigned to the electronic stability program. With the aid of this information, it is advantageously achieved that the hydraulic pressure is first limited to the maximum achievable hydraulic pressure by the first actuator, and the second control device is operated to operate the second actuator only when this hydraulic pressure is insufficient to achieve the predetermined emergency deceleration. Here, the predetermined emergency deceleration is preferably (in particular, the minimum deceleration legally predetermined or required by the ECE regulating device).

[0005] According to a preferred extension of the invention, vehicle data is monitored to detect dangerous braking. By monitoring vehicle data to detect dangerous braking, it is advantageously ensured that the necessity for dangerous braking is reliably identified. Preferably, existing vehicle data is monitored, so that additional vehicle data or input signals do not need to be assigned to the braking system.

[0006] According to a preferred extension of the invention, the vehicle data includes the driver's actuation distance and speed of the brake pedal; and if the actuation distance and speed exceed predetermined limits, then dangerous braking is initiated. By monitoring the actuation distance and speed of the brake pedal actuation in this way, it can be determined, by means of simple evaluation logic, whether dangerous braking must be initiated. This monitoring can also be advantageously applied to braking systems in which the brake pedal or actuation of the brake pedal is completely mechanically decoupled from the braking circuit, i.e., the driver's braking is integrated into the pedal force simulator. Preferably, the simulator pressure and input lever travel derived from the brake pedal actuation are used to interpret the driver's braking request and to identify dangerous braking.

[0007] According to a preferred extension of the invention, the vehicle data includes sensor data from sensors that detect the vehicle's surroundings; and if a dangerous driving situation is identified during the evaluation of this sensor data, hazardous braking is initiated. In particular, when the distance to a vehicle ahead is too small or there is an obstacle in the lane, a hazardous driving situation exists, necessitating braking to avoid an accident. By monitoring and evaluating the sensor data from the sensors detecting the vehicle's surroundings for identifying hazardous driving situations, it is advantageously ensured that hazardous braking can be initiated promptly even before a driver's braking request, especially a braking request confirmed by the brake pedal, or even if the driver has not identified a hazardous driving situation or has not yet identified a hazardous driving situation in this way. Thus, the method can be advantageously executed even in the case of autonomous braking, i.e., without driver intervention.

[0008] According to a preferred extension of the invention, the actual deceleration of the vehicle is measured; and the second actuator is actuated only if the actual deceleration is less than a predetermined emergency deceleration. By actuating the second actuator only when the measured actual deceleration is insufficient, it is advantageously ensured that the second actuator is not unnecessarily actuated, or that the hydraulic pressure is not unnecessarily increased. Preferably, the purpose of monitoring whether full deceleration has been achieved is monitored here, wherein the actuation of the second actuator by the second control device is then also omitted. Similarly, by measuring the actual deceleration of the vehicle, it is advantageously and reliably identified whether the braking system is in a faulty state, especially a faulty state due to brake fade, in which the deceleration of the vehicle expected when the first actuator is actuated by the first control device cannot be achieved.

[0009] According to a preferred extension of the invention, the actual hydraulic pressure in the braking system is measured; and the second actuator is actuated only when the actual hydraulic pressure is less than a target hydraulic pressure predetermined according to a predetermined emergency deceleration. By actuating the second actuator only when the measured actual hydraulic pressure is insufficient, it is advantageously ensured that the second actuator is not actuated unnecessarily, or that the hydraulic pressure is not unnecessarily increased.

[0010] According to a preferred extension of the invention, if actual deceleration and / or actual hydraulic pressure cannot be measured, a second actuator is manipulated to generate the maximum possible hydraulic pressure. By manipulating the second actuator to generate the maximum possible hydraulic pressure in this way, an advantageous fallback is provided for situations where measurement data for actual deceleration or actual hydraulic pressure is unavailable. This improves the reliability of the braking system, ensuring sufficient deceleration during dangerous braking, at least in the event of sensor failure, through the second control device and the second actuator.

[0011] The key feature of the first and second control devices for a braking system according to the invention is that these control devices are specifically arranged to perform the method according to the invention. This leads to the advantages already mentioned.

[0012] The braking system according to the invention has first and second actuators for generating hydraulic pressure in the braking system, and the outstanding feature of the braking system is the control device according to the invention. From this, the advantages already mentioned are also derived. Attached Figure Description

[0013] Other preferred features and combinations thereof are derived from this disclosure. The invention will now be described in more detail with reference to the accompanying drawings.

[0014] Figure 1 The braking system is illustrated in a schematic diagram;

[0015] Figure 2 A method for operating a braking system is shown;

[0016] Figure 3 The characteristic curves of the pressure change process in the braking system are shown; and

[0017] Figure 4 Other characteristic curves of the pressure change process in the braking system are shown. Detailed Implementation

[0018] Figure 1The components of the braking system 1 of vehicle 2 are illustrated in schematic. The braking system 1 has a first actuator 3 and a second actuator 4. The first actuator 3 and the second actuator 4 are respectively configured to generate hydraulic pressure in the braking system 1, such that braking pressure can be applied to the wheel braking devices of vehicle 2 (not shown in more detail). Furthermore, the braking system 1 also has a first control device 5 and a second control device 6. The first control device 5 is connected to the first actuator 3 via communication technology and is configured to operate the first actuator 3. Additionally, the first control device 5 is connected to the second control device 6 via communication technology and is configured to operate the second control device 6. Furthermore, the first control device 5 is connected to vehicle 2 via communication technology, such that, in particular based on vehicle data of vehicle 2, the first control device 5 can monitor whether the braking system 1 is performing dangerous braking.

[0019] See below for reference. Figure 2 This describes an advantageous method for a braking system 1 used in operating vehicle 2. To this end, Figure 2 The method is illustrated in the flowchart. In particular, this method ensures that when a dangerous braking situation is detected, vehicle 2 is reliably and quickly braked to a stop using a pre-defined emergency deceleration, or undergoes full deceleration.

[0020] In step S1, the method begins monitoring whether the braking system is engaging in dangerous braking. To detect dangerous braking, vehicle data of vehicle 2 is preferably monitored. This vehicle data preferably includes: the driving distance and speed at which the driver operates the brake pedal; and / or sensor data from sensors of vehicle 2 that detect the surrounding environment of vehicle 2.

[0021] In step S2, this vehicle data is evaluated, and it is checked whether dangerous braking must be initiated. Preferably, dangerous braking is initiated if the driver's braking distance and speed exceed predetermined limits. Furthermore, preferably, dangerous braking is initiated if a dangerous driving situation is identified when evaluating sensor data from sensors that detect the vehicle's surroundings. If it is now determined that dangerous braking is unnecessary, especially since neither predetermined limits are exceeded when the brake pedal is operated, nor is a dangerous driving situation present, the method ends at step S6.

[0022] However, if it is determined that dangerous braking must be initiated, the method continues to step S3. In step S3, the first control device 5 manipulates the first actuator 3 to generate a first hydraulic pressure p1 to achieve a predetermined emergency deceleration of the vehicle 2. The predetermined emergency deceleration is in particular a legally predetermined minimum deceleration.

[0023] In step S4, now, preferably at a predetermined time point after the actuator 3 is operated by the first control device 5, it is checked whether the deceleration achieved by the first actuator 3 is less than a predetermined emergency deceleration. Preferably, for this purpose, the actual deceleration of the vehicle is measured and compared with the predetermined emergency deceleration. If the achieved deceleration or actual deceleration is at least as large as the predetermined emergency deceleration, the method also ends in step S6. This situation will also depend on... Figure 3 The pressure change process shown in the figure is used to describe it.

[0024] However, if the deceleration achieved by the first actuator 3 is actually less than the predetermined emergency deceleration, if the achieved deceleration or actual deceleration cannot be measured, or if the achievable deceleration is already less than the predetermined emergency deceleration, then the method continues to step S5. In step S5, the first control device 5 manipulates the second control device 6 to manipulate the second actuator 4 to generate a second hydraulic pressure p2 in order to achieve the predetermined emergency deceleration. This situation will also depend on... Figure 4 The pressure change process is described as shown in the diagram. The method then ends at step S6, preferably with the full deceleration of vehicle 2 achieved.

[0025] Figure 3 Characteristic curves depicting the pressure change process in braking system 1 under identified dangerous braking conditions are shown. These characteristic curves are illustrated in the following graph: in this graph, the x-axis depicts time t, and the y-axis depicts pressure p. Based on... Figure 3 The pressure change process described in the text is based on the... Figure 2 As can be recognized from the description, the method performed according to the invention has been identified in step S4 as having achieved sufficient deceleration, and the method terminates without having to increase the hydraulic pressure via the second actuator 4.

[0026] First, at time t0, the driver initiates the braking process, during which the braking pressure p at the wheel brakes... B The first hydraulic pressure p1 in the braking system increases linearly and is the same. At time t1, the first control device 5 initiates the dangerous braking, causing the now pre-given hydraulic pressure p1 to rise linearly. H The process of change is designed to achieve a pre-defined emergency deceleration. At time t2, the maximum braking pressure p at these wheel braking devices is reached. Bmax Or the pressure of death.

[0027] Now, the anti-lock braking system (ABS) intervenes in the braking process in a modulating manner. If the wheels are about to lock up, the ABS will apply braking pressure p. BFirst, the braking pressure is reduced until the tendency to lock up stops, and then immediately increased again. Therefore, the braking pressure p at these wheel brakes... B Starting from time point t2, around the maximum braking pressure p Bmax oscillation.

[0028] After time point t2, the first hydraulic pressure p1 continues to rise until it reaches its maximum. 1max In this case, the maximum first hydraulic pressure p 1max With a pre-given hydraulic pressure p H The same size, and greater than the maximum braking pressure p. Bmax This allows for the achievement of a pre-defined emergency deceleration. Therefore, it is not necessary to generate a higher second hydraulic pressure p2 via the second actuator 4.

[0029] Figure 4 Additional characteristic curves depicting the pressure change process in braking system 1 under the identified dangerous braking conditions are shown. These characteristic curves are also illustrated in the following graph: in this graph, the x-axis depicts time t, and the y-axis depicts pressure p. Based on... Figure 4 The pressure change process described in the text is based on the... Figure 2 As can be seen from the description, the method performed according to the invention, in which it has been identified in step S4 that the achieved deceleration is insufficient and that the hydraulic pressure must be increased by the second actuator 4.

[0030] If already Figure 3 As described, the driver initiates the braking process at time t0 as follows: during this braking process, the braking pressure p at the wheel braking devices... B The first hydraulic pressure p1 in the braking system increases linearly and is the same. At time t1, the first control device 5 initiates the dangerous braking again, causing the now pre-given hydraulic pressure p1 to rise linearly. H The process of change is designed to achieve a pre-defined emergency deceleration. The first hydraulic pressure p1 continues to rise after time point t1 until it reaches its maximum value p. 1max At time point t3, it was identified that the first hydraulic pressure p1 was less than the maximum braking pressure p at these wheel braking devices. Bmax Therefore, the second actuator 4 is manipulated to increase the hydraulic pressure p H Increase to the maximum second hydraulic pressure p 2max The maximum second hydraulic pressure p 2max Greater than the maximum braking pressure p Bmax This allows for pre-defined emergency deceleration.

[0031] Now, the braking pressure p BContinue increasing the pressure until the maximum braking pressure p at these wheel brakes is reached. Bmax Then, as described above, the anti-lock braking system intervenes again in an adjustable manner during the braking process, causing the braking pressure p... B At maximum braking pressure p Bmax The surrounding area oscillates to achieve a pre-defined emergency deceleration.

Claims

1. A method for operating a braking system (1) of a vehicle (2), the braking system comprising: a first actuator (3) and a second actuator (4) for generating hydraulic pressure in the braking system (1); a first control device (5) configured to operate the first actuator (3); and a second control device (6) configured to operate the second actuator (4); wherein the braking system (1) is monitored for dangerous braking; wherein if dangerous braking is detected, the first actuator (3) is operated by the first control device (5) to generate a first hydraulic pressure for achieving a predetermined emergency deceleration of the vehicle (2); characterized in that, If the deceleration achieved or achievable by the first actuator (3) is less than the predetermined emergency deceleration, then the second control device (6) is controlled by the first control device (5) to operate the second actuator (4) to generate a second hydraulic pressure.

2. The method according to claim 1, characterized in that, In order to detect dangerous braking, vehicle data of the vehicle (2) is monitored.

3. The method according to claim 2, characterized in that, The vehicle data includes the distance and speed at which the driver operates the brake pedal; and if the operating distance and the speed exceed predetermined limits, the dangerous braking is initiated.

4. The method according to claim 2, characterized in that, The vehicle data includes sensor data from sensors of the vehicle (2) that detect the surrounding environment of the vehicle (2); and if a dangerous driving situation is identified when evaluating the sensor data, the dangerous braking is initiated.

5. The method according to any one of claims 1-4, characterized in that, The actual deceleration of the vehicle (2) is measured; and the second actuator (4) is only operated when the actual deceleration is less than the pre-given emergency deceleration.

6. The method according to claim 5, characterized in that, If the actual deceleration and / or the actual hydraulic pressure cannot be measured, the second actuator (4) is manipulated to generate the maximum possible hydraulic pressure.

7. The method according to any one of claims 1-4, characterized in that, The actual hydraulic pressure in the braking system (1) is measured; and the second actuator (4) is only operated when the actual hydraulic pressure is less than the target hydraulic pressure given in accordance with the pre-given emergency deceleration.

8. The method according to claim 7, characterized in that, If the actual deceleration and / or the actual hydraulic pressure cannot be measured, the second actuator (4) is manipulated to generate the maximum possible hydraulic pressure.

9. First and second control devices (5, 6) for a braking system (1), characterized in that, The control devices (5, 6) are arranged to perform the method according to any one of claims 1 to 8.

10. A braking system (1) of a vehicle (2), the braking system (1) having first and second actuators (3, 4) for generating hydraulic pressure in the braking system (1), characterized in that The first and second control devices (5, 6) according to claim 9.

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