Method for monitoring a brake system of a vehicle, control unit, brake system, drive system and vehicle with control unit

Abstract

The invention relates to a method (200) for monitoring a brake system (114) of a vehicle (100), wherein the method (200) comprises a step of reading in (201) a tire force acting on a tire of a wheel (102) and a current brake pressure in a brake system (106) for braking the wheel (102), a step of calculating (203) a braking effect parameter of the brake system (114) using the tire force and the brake pressure, and a step of outputting (205) a notification signal in response to the calculated braking effect parameter of the brake system (114).

Description

[0001] R. 414363

[0002] - 1 -

[0003] Description

[0004] title

[0005] Method for monitoring a vehicle's braking system, control unit, braking system, drive system and vehicle with control unit

[0006] The invention relates to a method for monitoring a vehicle's braking system, a control unit, a braking system, a drive system, and a vehicle with a control unit according to the preamble of the dependent claims. The present invention also relates to a computer program.

[0007] The problem with braking systems is that a user cannot easily check the brake pads and brake wear over a period of time, which creates a potential risk while driving a vehicle.

[0008] Against this background, the approach presented here comprises a method for monitoring a vehicle's braking system, a control unit that uses this method, and finally a corresponding computer program according to the main claims. Advantageous further developments and improvements of the device specified in the independent claim are possible through the measures listed in the dependent claims.

[0009] The approach presented here is designed to detect wear on the brakes or braking system, as well as situation-related conditions affecting the braking system, and, for example, to notify or warn a user. Furthermore, the approach presented here is designed to, for example, issue a message, or to decelerate the vehicle through a braking intervention induced by the message, or, for example, to display an R. 414363

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[0011] To limit the vehicle's acceleration if, for example, the brakes are deemed no longer powerful enough.

[0012] A method for monitoring a vehicle's braking system is presented. This method can include a step of reading the tire force acting on a wheel and the current brake pressure in the braking system for decelerating the wheel. Furthermore, the method includes a step of calculating a braking effect parameter of the braking system using the tire force and brake pressure, and a step of outputting a notification signal, where the output step can be performed in response to the calculated braking effect parameter of the braking system.

[0013] According to one embodiment, the method can be designed to determine the braking behavior and function of the vehicle's braking system. This method can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, such as in a control unit. According to one embodiment, the vehicle can be a passenger car with a braking system. According to an alternative embodiment, the vehicle can also be a truck. In the reading step, according to one embodiment, a hydraulic and / or pneumatic (braking) pressure from a braking system is read, in which, for example, brake fluid or compressed air is forced against a piston in the braking system to press brake pads against brake discs.Furthermore, a tire parameter can be read in the reading step, representing, for example, a torque or forces acting on the tire, which can also be obtained from other sensor elements for vehicle stability. Alternatively, special tire sensors can be used, which are attached in or to the tire and can output corresponding data. According to one embodiment, the tire force acting on the wheel can be a longitudinal force. According to another embodiment, the vehicle's braking performance can degrade over time, for example, due to wear, so the step of calculating a braking effect parameter should or can be performed as soon as a brake is applied. According to another embodiment, in the step of R. 414363.

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[0015] Based on the braking performance parameter, a notification signal is sent to a unit in the vehicle. This allows the brake condition to be communicated to other vehicle components or to the user / driver in a timely manner, thus increasing safety.

[0016] The process can, in the output step, transmit a notification signal to a user interface to inform a vehicle occupant about the braking effect and / or a driver assistance system. According to one embodiment, the user interface can be a display. Alternatively, the notification signal can also be emitted as an audible signal from the user interface. This allows the user to adjust their braking behavior as quickly as possible.

[0017] During the data acquisition step, the vehicle's speed and / or the temperature of the tire attached to the wheel and / or a component of the braking system can also be read. In the subsequent calculation step, the braking performance parameters are calculated using this speed and / or temperature. By reading the temperature of the braking system component or, indirectly, the tire temperature, potential deformation or reduction in braking performance, or alternatively, an overheating tire, can be detected early, and a signal can be issued to adjust the user's braking behavior. Furthermore, by considering the speed, a deterioration in the braking performance of the tire or wheel can be estimated and factored into the braking performance parameters.For example, this can also be used to set a reduced power output of the drive motor if it is known that the brakes cannot provide maximum braking power.

[0018] In the input step, the tire force can be entered as a vertical force, longitudinal force, and / or lateral force acting on the tire. By considering these forces, the tire's braking behavior can be estimated very precisely, which in turn allows conclusions to be drawn about the actual functionality of the braking system. In the calculation step, the braking efficiency can be expressed as R. 414363

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[0020] Braking performance parameters can be calculated. This allows for the determination of a quantity that is technically very easy to process further.

[0021] During the output step, a notification signal can be issued when the braking effect parameter and the brake pressure are in a predetermined relationship to a threshold value. According to one embodiment, the threshold value can, for example, correspond to an absolute braking value below 50% of the maximum braking power. Alternatively, the notification signal can be issued when a specific brake pressure is no longer reached in the braking system.

[0022] The steps of the procedure can be repeated cyclically and / or performed on different tires of the vehicle. This allows for repeated tire testing, leading to improved vehicle safety.

[0023] A control unit can be configured to execute and / or control the steps of the process in corresponding units. The approach presented here further provides a control unit configured to execute, control, or implement the steps of a variant of the process presented here in corresponding devices. This embodiment of the invention, in the form of a control unit, also allows the underlying problem to be solved quickly and efficiently.

[0024] For this purpose, the control unit can have at least one processing unit for processing signals or data, at least one storage unit for storing signals or data, at least one interface to a sensor or actuator for reading sensor signals from the sensor or for outputting data or control signals to the actuator, and / or at least one communication interface for reading or outputting data embedded in a communication protocol. The processing unit can be, for example, a signal processor, a microcontroller, or the like, and the storage unit can be flash memory or a magnetic storage unit. The communication interface can be configured to read or output data wirelessly and / or via a wired connection, wherein an R. 414363

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[0026] Communication interface that can read or output wired data, for example, by reading this data electrically or optically from a corresponding data transmission line or outputting it into a corresponding data transmission line.

[0027] In this context, a control unit can be understood as an electrical device that processes sensor signals and outputs control and / or data signals accordingly. The control unit can have an interface, which may be implemented in hardware and / or software. In the case of a hardware-based interface, the interfaces can, for example, be part of a so-called system ASIC, which incorporates various functions of the control unit. However, it is also possible that the interfaces are separate integrated circuits or at least partially comprised of discrete components. In the case of a software-based interface, the interfaces can be software modules, which, for example, are located on a microcontroller alongside other software modules.

[0028] A computer program that can be configured to execute and / or control the steps of the method. Also advantageous is a computer program product or computer program with program code that can be stored on a machine-readable medium or storage medium such as semiconductor memory, hard disk memory, or optical memory and is used to execute, implement, and / or control the steps of the method according to one of the embodiments described above, particularly if the program product or program is executed on a computer or control unit.

[0029] A braking system for a vehicle can comprise a braking system for decelerating a wheel of the vehicle and a variant of a control unit presented here, wherein the braking system further comprises a brake control unit for controlling the deceleration of the wheel using the braking effect parameter. The advantages presented here can also be realized quickly and efficiently with such an embodiment. R. 414363

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[0031] A vehicle drive system can comprise a drive motor for powering the wheels and a variant of the control unit presented here, where the drive motor is configured to drive the wheels using the braking effect parameter. This can significantly improve driving safety compared to conventional approaches, as potentially poor braking performance can already be taken into account when determining the drive power.

[0032] According to one embodiment, the drive motor can be designed to drive the wheels with a maximum torque that depends on the braking effect parameter. This ensures that safe braking of a vehicle can be guaranteed even under unfavorable braking performance conditions.

[0033] According to one embodiment, a vehicle may include a variant of the control unit presented here, in particular wherein the vehicle further includes a braking system and / or a drive system.

[0034] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows:

[0035] Fig. 1 shows a schematic representation of a vehicle according to an exemplary embodiment;

[0036] Fig. 2 shows a flowchart of a process according to an exemplary embodiment; and

[0037] Fig. 3 shows a representation of a brake system according to an exemplary embodiment.

[0038] In the following description of advantageous embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, thus omitting a repeated description of these elements. R. 414363

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[0040] Fig. 1 shows a schematic representation of a vehicle 100 according to an exemplary embodiment. The vehicle 100 has at least one wheel 102, but here 4 wheels 102, a control unit 104, a brake system 106, a brake control unit 108, a drive system 110 and a drive motor 112.

[0041] According to one embodiment, the vehicle 100 is designed as a motor vehicle, for example, a car or a truck. In this embodiment, the vehicle 100 comprises four wheels 102. According to an alternative embodiment, the vehicle 100 can also comprise only two wheels 102, in which case the vehicle 100 is designed as a motorcycle or another motorized two-wheeled or single-track vehicle. According to one embodiment, the wheels 102 are designed to accommodate tires. These tires are, for example, designed as "smart tires," i.e., tires with sensors to detect braking. Alternatively, braking force can also be detected as tire force by other sensors, such as torque sensors for wheel slip. According to one embodiment, the vehicle 100 comprises the drive system 110, which is designed to control the drive motor 112.According to one embodiment, the drive motor 112 is designed to drive the wheels 102 specifically using a braking effect parameter. According to another embodiment, the drive motor 112 drives all wheels 102 synchronously and / or equally or with the same torque. The wheels 102 are driven up to a maximum torque that depends on the braking effect parameter. Furthermore, the drive motor 112 and the drive system 110 are controlled by the control unit 104.

[0042] According to one embodiment, the control unit 104 is also configured to control the brake system 106 and the brake control unit 108. According to one embodiment, the brake system 106 is configured to decelerate the vehicle 100 in response to the application of a brake pedal. In this process, the brake control unit 108, according to one embodiment, brakes the wheels 102 of the vehicle 100 using the braking effect parameter. According to one embodiment, the brake system 106 also includes, for example, an anti-lock braking system. R. 414363

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[0044] Furthermore, the control unit 104 is designed to execute a method for monitoring a brake system 114 of a vehicle 100. According to one embodiment, the brake system 114 can be installed or combined with the necessary sensors, for example to perform tire force detection, in any passenger car or truck.

[0045] Fig. 2 shows a flowchart of a method 200 according to an exemplary embodiment. According to this exemplary embodiment, the method 200 is intended for use in a vehicle described in Figure 1. The method 200 for monitoring a vehicle's brake system 114 comprises a step 201 of reading a tire force acting on a tire of a wheel and a current brake pressure in a brake system for decelerating the wheel, a step 203 of calculating a brake effect parameter of the brake system 114 using the tire force and the brake pressure, and a step 205 of outputting a notification signal responding to the calculated brake effect parameter of the brake system 114.

[0046] In the initial reading step, according to a particular embodiment, the vehicle's speed and / or the temperature of the tire attached to the wheel and / or at least one component of the braking system are read in. This allows, for example, any changes to the tires, the braking system components, or their temperatures to be detected early and used to determine the braking performance parameter. According to another embodiment, the tire force read in the initial reading step is a vertical, longitudinal, or lateral force acting on the tire. Furthermore, according to this embodiment, in step 203, the braking performance parameter is calculated using the speed and the temperature of the tires.

[0047] According to one embodiment, the step of outputting the notification signal is executed in response to step 203 of calculating the braking effect parameter. According to one embodiment, in the output step, the notification signal is sent to a user interface to inform a vehicle occupant about the braking effect and / or R. 414363

[0048] - 9 - a driver assistance system such as an ABS and / or ESP control unit. According to one embodiment, the user interface is designed as a display on a dashboard. According to one embodiment, the notification signal is output in step 201 of the output process when the braking performance parameter is in a predetermined relationship to a threshold value. The threshold value corresponds, for example, to an absolute braking value below 50% of the brakes' power. Alternatively, the notification signal is output even at a reduced braking power of 70%, or when a certain brake pressure is no longer present.

[0049] According to one embodiment, steps 201, 203, and 205 of method 200 are repeated cyclically. Alternatively, steps 201, 203, and 205 of method 200 are performed on different tires of the vehicle. According to one embodiment, the tires include so-called tire sensors. These tire sensors can measure the forces acting on the tire. These forces are usually measured in all three directions and are available as the vertical force, the longitudinal force, and the lateral force for further determination of the braking effect parameter.

[0050] The approach presented here, according to one embodiment, is designed as a logic that uses the measured tire forces and combines them with the measured or estimated brake fluid pressure to estimate the braking effect of each brake. This logic can then determine whether the braking effect has diminished. This information is relayed to the driver and to a vehicle dynamics control system, such as an electronic stability program, to adjust the system accordingly.

[0051] Fig. 3 shows a brake system 114 according to an exemplary embodiment. According to this exemplary embodiment, the brake system 114 is designed like the brake system described in Figure 1. The brake system 114 comprises a user interface 302, an actuating unit 304, a transmission unit 306, a wheel brake 308, and the wheel 102.

[0052] According to one embodiment, the brake system 114 is activated by actuating the user interface 302. The user interface 302 is R. 414363

[0053] - 10 - according to one embodiment, the actuating unit 304 is designed as a pedal which initiates braking when a user depresses the pedal. The actuating unit 304 is actuated by a force Fi from the user interface 302. According to one embodiment, the actuating unit 304 includes an amplifier which transmits the force as a further force F2 to the transmission unit 306. According to one embodiment, the transmission unit 306, in response to the further force F2, controls the wheel brake 308, which, according to one embodiment, is designed to stop the wheel 102. Figure 3 also shows some physical formulas that illustrate the relationships of the braking system.

[0054] According to one embodiment, the method calculates the brake efficiency as a braking performance parameter. For this, the method requires signals for the longitudinal force and the brake pressure. According to one embodiment, the longitudinal force is determined by means of a sensor located on the tire. According to another embodiment, the brake pressure is the pressure with which the brake fluid presses against the pistons in the brake system 114, causing them to press the brake pads against the brake discs.

[0055] According to one embodiment, the method also uses other signals, such as the vehicle's speed or the tire temperature. These signals can be used to measure how much torque the brake generates as a function of the brake pressure at a wheel. This is advantageous because a faulty or malfunctioning brake generates less braking torque for the same pressure.

[0056] In this case, the logic, also called the procedure, can calculate a value CP, but it can also calculate a value C* or other values ​​that all show the same or similar thing: the braking effect of this brake.

[0057] The CPbrake value represents the capacity or braking ability of the vehicle's brakes. The CPbrake value is related to R. 414363.

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[0059] The braking torque Mbrake and the pressure Pcaiiper are calculated as the result of dividing the braking torque Mbrake by the pressure Pcaiiper, where the braking torque Mbrake is measured in Newton meters and the pressure Pcaiiper in bar. These braking values ​​are calculated individually for each brake every time it is used, whether by the driver or by other systems such as the VDC (Vehicle Dynamic Control).

[0060] These values ​​are calculated in order to either warn the driver, change the control strategy of the electronic stability program, or limit the maximum speed of the vehicle.

[0061] According to one embodiment, the driver or vehicle occupant will receive a warning via the user interface, which will issue a message if the braking system 114 has reduced braking effectiveness. According to another embodiment, the user interface can even provide a more detailed announcement, if desired, indicating which part of the brake is malfunctioning.

[0062] The electronic stability program will use the CP value (or braking force in general) to adjust its control strategy. It is crucial for controllers like the VDC or anti-lock braking system to know how much pressure to apply to the brakes to achieve the desired effect.

[0063] In cases of very low braking effect, this logic can reduce engine power and thus guarantee a safe journey to the workshop.

[0064] The driver cannot always know the current condition of their brake system 114. When the brake pads are completely worn, a message appears in the user interface because there is a sensor at the end of the pads; or, if the driver visits a workshop, the mechanic can measure the wear. Otherwise, the driver has no information about the condition of their brake system 114. R. 414363

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[0066] Especially when the brake system 114 gets too hot, for example on a racetrack, when driving downhill, or when braking from high speeds, or when the track is wet or dirty, for example due to heavy rain, salt in winter, oil splashes, or rust, or simply due to age, the braking performance of this system is not as expected. In some of these situations, the brake system 114 is even damaged, resulting in the expected braking performance never being achieved again.

[0067] If an embodiment includes an "and / or" connection between a first feature and a second feature, this is to be read as meaning that the

[0068] An embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment has either only the first feature or only the second feature.

Claims

R. 414363 - 13 - Claims 1. Method (200) for monitoring a braking system (114) of a vehicle (100), wherein the method (200) comprises the following steps: Reading (201) a tire force acting on a tire of a wheel (102) and a current brake pressure into a brake system (106) for braking the wheel (102); Calculating (203) a braking performance parameter of the braking system (114) using the tire force and the brake pressure; and outputting (205) a notification signal responding to the calculated braking performance parameter of the braking system (114).

2. Method (200) according to claim 1, wherein in step (205) of output the notification signal is output to a user interface to inform a vehicle occupant about the braking effect and / or a driver assistance system.

3. Method (200) according to one of the preceding claims, wherein in step (201) of reading in a speed of the vehicle (100) and / or a temperature of the tire attached to the wheel (102) and / or a component of the brake system (114) is further read in, and wherein in step (203) of calculating the brake effect parameters is calculated using the speed and / or the temperature.

4. Method (200) according to one of the preceding claims, wherein in step (201) of reading in a tire force a vertical force and / or longitudinal force and / or lateral force acting on the tire is read in. R. 414363 - 14 - 5. Method (200) according to one of the preceding claims, wherein in step (203) of the calculation the braking efficiency is calculated as a braking efficiency parameter.

6. Method (200) according to one of the preceding claims, wherein in step (205) of output the notification signal is output when the braking effect parameter and / or the brake pressure is in a predetermined relationship to a threshold value.

7. Method (200) according to one of the preceding claims, in which the steps (201 , 203, 205) of the method (200) are repeated cyclically and / or are performed for different tires on different tires of the vehicle (100).

8. Control unit (104) configured to perform and / or control the steps (201, 203, 205) of the method (200) according to any of the preceding claims in corresponding units.

9. Computer program configured to execute and / or control the steps (201, 302, 205) of the method (200) according to any of the preceding claims in corresponding units when the computer program is executed on a control unit or device.

10. Machine-readable storage medium on which the computer program according to claim 9 is stored.

11. Braking system (106) for a vehicle (100) comprising a braking system (106) for braking a wheel (102) of the vehicle (100) and a control unit (104) according to claim 8, wherein the braking system (106) further comprises a brake control unit (108) for controlling the braking of the wheel (102) using the braking effect parameter. R. 414363 - 15 - 12. Drive system (110) for a vehicle (100) comprising a drive motor (112) for driving the wheels (102), and the control unit (104) according to claim 8, wherein the drive motor (112) is configured to drive the wheels (102) using the braking effect parameter.

13. Drive system (110) according to claim 12, wherein the drive motor (112) is configured to drive the wheels (102) with a maximum torque dependent on the braking effect parameter.

14. Vehicle (100) with a control unit (104) according to claim 8, in particular wherein the vehicle (100) further comprises a braking system (106) according to claim 11 and / or a drive system (110) according to one of claims 12 or 13.

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