Method for operating a braking system of a parked motor vehicle and motor vehicle

Abstract

The present invention relates to a method for operating a braking system (1) of a motor vehicle (2) for parking the motor vehicle (2). The method comprises: - Stopping the motor vehicle (2) in a parking position, - Determining an initial as-is state of a first parking brake (3) of the braking system (1) by means of a detection device (4) of the motor vehicle (2), - Determining a second actual state of a second parking brake (5) of the braking system (1) by the determination device (4), - Determining a control specification by a control device (6) of the motor vehicle (2) by analyzing the determined first actual state and the determined second actual state, and - Control of the first parking brake (3) and the second parking brake (5) by the control device (6) with the control specification. Furthermore, the invention relates to a motor vehicle (2) which is designed to carry out the method according to the invention.

Description

[0001] The present invention relates to a method for operating a braking system of a parked motor vehicle according to the preamble of claim 1. Furthermore, the invention relates to a motor vehicle according to the preamble of claim 10.

[0002] Electromechanical brakes offer the possibility of equipping more than two wheel brakes with parking brake actuators in a cost-effective manner. These additional parking brake actuators can be used to distribute the holding forces during parking across any of the wheels and also to vary which wheels are held during the parking process. Brakes with a parking brake actuator are referred to as parking brakes within the scope of the invention.

[0003] When the parking brake is engaged, rusted brake discs leave wear marks upon release, noticeably impairing comfort. This can lead to disturbing noises and / or vibrations when driving. In extreme cases, severe rusting or freezing can prevent the brake disc and pads from releasing when the parking brake actuator retracts. The consequence, at least with low friction, would be a locked wheel that only releases later, for example, due to vibrations.

[0004] Document DE 10 2020 208 718 B3 discloses a method for operating a motor vehicle's braking system for parking the vehicle. The braking system includes a parking lock and an electric parking brake. First, the vehicle is parked in a parking space and secured against rolling away by the parking lock and the electric parking brake. A sensor detects the road's incline. If the vehicle is parked on a level surface, the electric parking brake is released after a first time interval. Furthermore, the system can be configured to activate and release the electric parking brake again after a second time interval. This prevents the electric parking brake from seizing.

[0005] Document DE 10 2017 212 364 B4 discloses a further method for operating a motor vehicle's braking system for parking the vehicle. The braking system also includes a parking lock and an electric parking brake. First, the environment of the parked vehicle is analyzed. For this purpose, weather data or road surface data, such as road gradient, road type, road surface condition, or the presence of a curb, are recorded. Based on the environmental data, the required holding forces of the parking lock and the electric parking brake are calculated. By shifting the holding force towards the parking lock, the risk of corrosion of the electric parking brake can be reduced.

[0006] Document DE102019101530A1 discloses an alternative method for operating a motor vehicle's braking system for parking the vehicle. The braking system also includes a parking lock and an electric parking brake. When a low ambient temperature is detected, the electric parking brake is released, so that the braking force is provided entirely by the parking lock. This prevents the electric parking brake from freezing.

[0007] Known methods for operating the braking systems of motor vehicles for parking purposes have the disadvantage that only general environmental data of the vehicle are considered when controlling the brakes. The actual condition of the individual brakes is not taken into account. Thus, there remains either an increased risk of the electric parking brake seizing and / or freezing, or of insufficient holding force being provided, for example, in the event of a sudden strong wind or a collision with a moving vehicle. Furthermore, the prior art does not demonstrate the coordination of multiple electromechanical parking brakes, meaning that the known braking systems already have a relatively low performance capacity.

[0008] It is therefore an object of the present invention to eliminate, or at least partially eliminate, the disadvantages described above in a method for operating a braking system of a motor vehicle for parking the motor vehicle. In particular, it is an object of the present invention to provide a method and a motor vehicle that prevent freezing and / or rusting of components of the parking brake in a simple and cost-effective manner.

[0009] The aforementioned problem is solved by the claims. Accordingly, the problem is solved by a method for operating a braking system of a motor vehicle for parking the motor vehicle, comprising the features of independent claim 1, and by a motor vehicle comprising the features of dependent claim 10. Further features and details of the invention become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention for operating a braking system of a motor vehicle for parking the motor vehicle naturally also apply in connection with the motor vehicle according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always makes, or can make, reciprocal references.

[0010] According to a first aspect of the invention, the problem is solved by a method for operating a braking system of a motor vehicle for parking the motor vehicle. The method comprises: - Stopping the motor vehicle in a parking position, - Determining an initial status of the first parking brake of the braking system by means of a vehicle detection device, - Determining a second current state of a second parking brake of the braking system using the detection device, - Determining a control input by a motor vehicle control device through an analysis of the determined first actual state and the determined second actual state, and - Control of the first parking brake and the second parking brake by the control device with the control specification.

[0011] First, the vehicle is navigated into a parking position and held there. For the purposes of this invention, "holding" means bringing the vehicle to a complete stop. This can be achieved, for example, by deliberately activating a drive system of the vehicle. Additionally or alternatively, the vehicle can be brought to a stop by its braking system. Alternatively, it can also be brought to a stop by rolling resistance, transmission resistance, and / or a road incline.

[0012] Furthermore, the initial condition of the first parking brake in the braking system is determined by the vehicle's detection device. This initial condition encompasses aspects that affect the operation and wear of the first parking brake, such as its wear level, contamination status, component temperature, component moisture content, ice deposits, snow deposits, and the like. Component moisture, for example, can increase the tendency to rust and reduce the holding force of the first parking brake. Additionally, if the component temperature is below freezing, the risk of the first parking brake freezing is increased.

[0013] Furthermore, the second "actual state" of the second parking brake in the braking system is determined by the vehicle's detection device. This second "actual state" refers to aspects that affect the operation and wear of the second parking brake, such as wear, contamination, component temperature, component moisture, ice deposits, snow deposits, or similar factors. Component moisture, for example, can increase the tendency to rust and reduce the holding force of the second parking brake. Additionally, if the component temperature is below freezing, the risk of the second parking brake freezing is increased.

[0014] The control device determines the control setting based on the first and second actual states. Within the scope of the invention, a control setting is understood to be a setting that defines the parameters with which the respective parking brake is to be controlled over time. Accordingly, the first actual state might, for example, state that the first parking brake is in a condition in which temporary use is possible without problems, but prolonged use, for example, over a period exceeding 30 minutes, leads to an increased risk of freezing. The second actual state might, for example, state that the second parking brake is in a condition in which current use poses an increased risk of freezing.From this, the control device derives, for example, the control instruction that the first parking brake is activated to hold the vehicle in the park position, while the second parking brake remains deactivated for regeneration or is operated in such a way that an improvement of the second actual state is to be expected, for example by actuation, preferably intermittent actuation, heating by an additional heating device, cooling by an active or passive airflow or the like.After approximately 30 minutes, the second parking brake can then be activated to hold the vehicle in the parked position, while the first parking brake is deactivated or operated in such a way as to improve the initial state, for example by actuation, preferably intermittent, heating by an additional heating device, cooling by active or passive airflow, or the like. According to the invention, the control device and the detection device can be provided by a common control device of the vehicle.

[0015] Finally, the control device controls the first parking brake and the second parking brake according to the control setting. According to the invention, it can be provided that the control setting is continuously or stepwise adjusted, for example, if the first actual state and / or the second actual state changes in such a way that the operational safety of the braking system can be further improved by changing the control setting.

[0016] An inventive method for operating a motor vehicle's parking brake system has the advantage over conventional methods that the efficiency and operational reliability of the brake system are significantly improved using simple means and in a cost-effective manner. By considering the actual first and second operating states when determining the control parameters, the first and second parking brakes can be operated more efficiently and reliably. With the inventive method, the individual parking brakes are operated selectively according to individual parameters and thus optimized, particularly with regard to preventing wear on the parking brakes.The risk of the first and second parking brakes freezing and rusting is therefore significantly reduced compared to known methods for operating brake systems.

[0017] According to a preferred embodiment of the invention, a method may be provided that, when determining the first actual state, a first temperature of the first parking brake and / or, when determining the second actual state, a second temperature of the second parking brake are determined by the detection device. Preferably, the first temperature is determined via a first temperature sensor of the vehicle. More preferably, the second temperature is determined via a second temperature sensor of the vehicle. The first temperature sensor and / or the second temperature sensor is preferably coupled to the detection device via data communication. The first temperature and / or second temperature is preferably determined continuously or at least repeatedly. By determining the temperature, for example, the risk of the respective parking brake freezing and the drying time of a wet parking brake can be determined.This has the advantage that the efficiency and operational safety of the braking system can be improved using simple means and in a cost-effective manner.

[0018] According to the invention, it is preferred that, when determining the first initial condition, the first moisture level of the first parking brake and / or, when determining the second initial condition, the second moisture level of the second parking brake are determined by the measuring device. The moisture can be in the form of water, snow, or ice, for example. The first moisture level and / or second moisture level is preferably determined continuously or at least repeatedly. By determining the moisture level, the risk of rust formation in the respective parking brake and the required drying time for the respective parking brake can be determined, for example. This has the advantage that the efficiency and operational reliability of the braking system are further improved in a simple and cost-effective manner.

[0019] Preferably, the first moisture level is determined via a first moisture sensor of the vehicle and / or the second moisture level via a second moisture sensor of the vehicle. The first moisture sensor and / or the second moisture sensor is preferably coupled to the detection device via data communication. The first moisture sensor can, for example, be arranged in the area of ​​the first parking brake on the vehicle and be designed to measure the moisture of the first parking brake. The second moisture sensor can, for example, be arranged in the area of ​​the second parking brake on the vehicle and be designed to measure the moisture of the second parking brake.Alternatively, the first and / or second humidity sensor can be configured to detect moisture at another location on the vehicle, for example, to detect precipitation such as snow, rain, hail, or the like, or to detect splashing moisture, for example, from puddles, a snow-covered roadway, or the like. Preferably, the first and / or second humidity sensor can also determine the direction from which the moisture is affecting the vehicle, such as the direction of rain caused by wind, the relative position of a puddle to the vehicle, or the like. This has the advantage of further improving the efficiency and operational reliability of the braking system in a simple and cost-effective manner.

[0020] In a particularly preferred embodiment of the invention, a method may be provided that, when determining the first current state, a first position of the first parking brake relative to the vehicle's surroundings and / or, when determining the second current state, a second position of the second parking brake relative to the vehicle's surroundings is determined by the determining device. The determination of the first position and / or second position is preferably carried out by the determining device. The determination of the first position and / or second position can be performed, for example, using the vehicle's navigation system. A navigation system can, for example, determine the current position of the vehicle. In combination with a parking guidance system, which allows the future parking position of the vehicle to be specified, the future position of the vehicle can also be predicted.This is particularly advantageous if, during the execution of the inventive method, the parking brakes are to be conditioned while the vehicle is moving to the parking position, for example, by selectively heating the parking brake which, in the parking position, faces away from the rain and is preferably used to hold the vehicle. Alternatively or additionally, vehicle sensors, such as PDC sensors of a parking assistance system for measuring the distance to objects in the vehicle's vicinity, lidar sensors, radar sensors, camera sensors, or the like, can be used for this purpose. For example, the vehicle's position relative to a roadway can be determined via the navigation system. PDC sensors can, for example, determine the vehicle's relative position to walls, shrubs, trees, bushes, or the like.Camera sensors can be used, for example, to determine the relative positions of puddles and other objects to the vehicle. This has the advantage that the efficiency and operational safety of the braking system can be further improved in a simple and cost-effective manner.

[0021] Preferably, the determined first position and / or second position is compared with direction- and / or position-dependent humidity parameters of the environment. This comparison is preferably performed by the detection device and / or the control device. Within the scope of the invention, humidity parameters are understood to be parameters that can influence the humidity of the first and second parking brakes, such as rain, snowfall, hail, puddles, and slush. The humidity parameters are usually direction-dependent, so that the different sides of the vehicle are exposed to the individual humidity parameters differently. For example, in the case of rain, snowfall, or hail, the wind direction plays a significant role, so that the parking brake on the leeward side of the vehicle is considerably less moistened by the precipitation than the parking brake on the windward side of the vehicle.Similarly, the relative position of a water accumulation, such as a puddle, slush, or the like, to the vehicle can be important for assessing the risk of the parking brakes becoming wet. In this context, it can also be relevant whether the water accumulation is on the road or sidewalk side of the vehicle, as water is particularly easily splashed onto the adjacent parking brake by passing vehicles. By comparing the first and / or second position with the direction- and / or position-dependent humidity parameters of the environment, the future moisture content of the first and / or second parking brake can be estimated, and the control parameters can be adjusted accordingly to prevent freezing and / or rusting.This has the advantage that the efficiency and operational safety of the braking system can be further improved using simple means and in a cost-effective manner.

[0022] According to a preferred embodiment of the invention, the first actual state and / or the second actual state are continuously or at least repeatedly determined, wherein the first parking brake is selectively deactivated by the control device depending on the first actual state, or the second parking brake depending on the second actual state, for improved regeneration. Continuous or at least repeated determination ensures that the first actual state or the second actual state is always up-to-date, so that the control device can adjust the control input accordingly. Such an adjustment preferably takes hysteresis into account, thus preventing the parking brakes from being activated and deactivated too frequently. This has the advantage that the efficiency and operational reliability of the braking system are further improved in a simple and cost-effective manner.

[0023] Preferably, the first parking brake and / or the second parking brake is conditioned by targeted application before the vehicle comes to a stop. This targeted application is preferably carried out by the control device. More preferably, the targeted application occurs in cooperation with a navigation system and / or a parking assistance system once a planned parking position has been determined. Targeted application of a parking brake allows it to be heated. This is particularly advantageous when the parking brake is damp and / or cold. In this context, the invention may, for example, provide that the parking brake exposed to sunlight in the parked position is applied less frequently than the parking brake on the shaded side, thus preventing excessive drying of the parking brake and reducing energy consumption.This has the advantage that the efficiency and operational safety of the braking system can be further improved using simple means and in a cost-effective manner.

[0024] According to the invention, it is preferred that the targeted actuation comprises a jerky actuation and / or actuation against a drive system of the motor vehicle. The jerky actuation is preferably carried out in such a way that dirt, ice, snow, water, or the like fall off the actuated parking brake due to their own inertia. Moreover, this prevents excessive heating of the actuated parking brake compared to continuous dragging operation of the parking brake. Actuation against the drive system of the motor vehicle is preferably carried out in conjunction with an increase in the drive torque of the drive system, so that the speed of the motor vehicle is not affected by the actuation of the first parking brake and / or the second parking brake. This has the advantage that the efficiency and operational reliability of the braking system are further improved in a simple and cost-effective manner.

[0025] According to a second aspect of the invention, the problem is solved by a motor vehicle. The motor vehicle has a drive system for propelling the motor vehicle and a braking system for braking the motor vehicle during driving and for locking the motor vehicle during parking. According to the invention, the motor vehicle is configured to carry out a method according to the invention.

[0026] The drive system is designed to propel the motor vehicle. For this purpose, the drive system comprises a motor, preferably an electric motor, and a transmission. According to the invention, the drive system can be configured to drive two or four wheels of the motor vehicle.

[0027] The braking system is designed to brake the vehicle while it is in motion and to secure it while it is parked. For braking, the braking system preferably comprises a first brake and a second brake. The first and second brakes are preferably electromechanical brakes. Preferably, the first brake is configured as a first parking brake, for example, by means of an additional first parking brake actuator. More preferably, the second brake is configured as a second parking brake, for example, by means of an additional second parking brake actuator.

[0028] The vehicle is equipped with a detection device to determine the initial actual state of the first parking brake and the second actual state of the second parking brake. The vehicle is also equipped with a control device to determine the control input and to control the first and second parking brakes according to this input.

[0029] The motor vehicle according to the invention offers all the advantages already described in the first aspect of the invention for operating a motor vehicle's braking system for parking. Accordingly, the motor vehicle according to the invention has the advantage over conventional motor vehicles that the efficiency and operational reliability of the braking system can be significantly improved with simple means and in a cost-effective manner. By taking into account the actual first and second states of operation when determining the control parameters, the first and second parking brakes can be operated more efficiently and reliably.In the vehicle according to the invention, the individual parking brakes can be operated in a targeted manner according to individual parameters and thus optimized, particularly with regard to preventing wear of the parking brakes. The risk of freezing or rusting of the first and second parking brakes is therefore significantly reduced compared to known vehicles.

[0030] A motor vehicle according to the invention and a method according to the invention for operating a braking system of a motor vehicle for parking the motor vehicle are explained in more detail below with reference to the drawings. The drawings schematically show: Fig. 1 in a side view a preferred embodiment of a motor vehicle according to the invention, and Fig. 2 in a flowchart a preferred embodiment of a method according to the invention.

[0031] Elements with the same function and mode of operation are in the Fig. 1 and Fig. 2 each with the same reference numerals.

[0032] In Fig. Figure 1 is a schematic side view of a preferred embodiment of a motor vehicle 2 according to the invention. For propelling the motor vehicle 2, the motor vehicle 2 has a drive system 9 with an electric motor 12 for generating drive torque and a traction battery 13 for storing and providing electrical energy to operate the electric motor 12. For controlling the electric motor 12 as required, the drive system 9 has a control device 6 and a detection device 4. The detection device 4 is coupled to several distance sensors 14 for measuring distances to objects in the environment U of the motor vehicle 2 via data communication.

[0033] For braking the motor vehicle 2, the motor vehicle 2 has a braking system 1. The braking system 1 has a wheel brake on a front wheel 15, which is designed as a first parking brake 3. On a rear wheel 16, the braking system 1 has a wheel brake, which is designed as a second parking brake 5. According to the invention, the second parking brake 5 can also be arranged on the front wheel 15, which is hidden in this view. Alternatively, a third parking brake (not shown) can be arranged on the hidden front wheel 15 and a fourth parking brake (not shown) can be arranged on the hidden rear wheel.

[0034] In the area of ​​the first parking brake 3, the braking system 1 has a first humidity sensor 7 for determining the humidity of the first parking brake 3 and a first temperature sensor 10 for determining the temperature of the first parking brake 3. In the area of ​​the second parking brake 5, the braking system 1 has a second humidity sensor 8 for determining the humidity of the second parking brake 5 and a second temperature sensor 11 for determining the temperature of the second parking brake 3. The detection device 4 and the control device 6 are also components of the braking system 1. The first parking brake, the second parking brake, and any further parking brakes can be controlled by the control device 6.

[0035] Fig.Figure 2 schematically illustrates a preferred embodiment of a method according to the invention for operating a braking system 1 of a motor vehicle 2 for parking the motor vehicle 2 in a flowchart. In a first process action 100, the motor vehicle 2 is stopped in a parked position. This is preferably done using the drive system 9 and the braking system 1. In a second process action 200, the detection device 4 of the motor vehicle 2 determines a first actual state of the first parking brake 3 of the braking system 1. In a third process action 300, the detection device 4 determines a second actual state of the second parking brake 5 of the braking system 1.

[0036] In a fourth process step 400, the control device 6 of the motor vehicle 2 determines a control input for controlling the first parking brake 3 and the second parking brake 5 to hold the motor vehicle 2 in the parked position. The control input is determined by analyzing the determined first actual state and the determined second actual state. According to the invention, the control device 6 may use artificial intelligence for this purpose. In a fifth process step 500, the control device 6 controls the first parking brake 3 and the second parking brake 5 with the control input. Reference symbol list 1. Braking system 2 motor vehicles 3 first parking brake 4 Investigation device 5 second parking brake 6 Control device 7 first humidity sensor 8 second humidity sensor 9 Drive system 10 first temperature sensor 11 second temperature sensor 12 Electric motor 13 Traction battery 14 Distance sensor 15 front wheel 16 rear wheel 100 first procedural action 200 second procedural action 300 third procedural action 400 fourth procedural action 500 fifth procedural action U surroundings QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 208 718 B3

[0004] DE 10 2017 212 364 B4

[0005] DE 102019101530A1

[0006]

Claims

[1] Method for operating a braking system (1) of a motor vehicle (2) for parking the motor vehicle (2), comprising: - stopping the motor vehicle (2) in a parking position, - Determining a first actual state of a first parking brake (3) of the braking system (1) by a determination device (4) of the motor vehicle (2), - Determining a second actual state of a second parking brake (5) of the braking system (1) by the determination device (4), - determining a control specification by a control device (6) of the motor vehicle (2) by analyzing the determined first actual state and the determined second actual state, and - Controlling the first parking brake (3) and the second parking brake (5) by the control device (6) with the control specification. [2] Method according to claim 1, characterized bythat when determining the first actual state, a first temperature of the first parking brake (3) and / or when determining the second actual state, a second temperature of the second parking brake (5) is determined by the determination device (4). [3] Method according to claim 1 or 2, characterized by that when determining the first actual state, a first humidity of the first parking brake (3) and / or when determining the second actual state, a second humidity of the second parking brake (5) is determined by the determination device (4). [4] Method according to claim 3, characterized by that the first humidity is determined via a first humidity sensor (7) of the motor vehicle (2) and / or the second humidity is determined via a second humidity sensor (8) of the motor vehicle (2). [5] Method according to claim 3 or 4, characterized bythat when determining the first actual state, a first position of the first parking brake (3) relative to an environment (U) of the motor vehicle (2) and / or when determining the second actual state, a second position of the second parking brake (5) relative to the environment (U) of the motor vehicle (2) is determined by the determination device (4). [6] Method according to claim 5, characterized by that the determined first position and / or second position is compared with direction- and / or position-dependent humidity parameters of the environment (U). [7] Method according to one of the preceding claims, characterized by that the first actual state and / or the second actual state is determined continuously or at least repeatedly, wherein the first parking brake (3) is deactivated in a targeted manner by the control device (6) as a function of the first actual state or the second parking brake (5) as a function of the second actual state for improved regeneration. [8] Method according to one of the preceding claims, characterized by that the first parking brake (3) and / or the second parking brake (5) is conditioned by targeted actuation before the motor vehicle (2) is stopped. [9] Method according to claim 8, characterized by that the targeted actuation comprises a jerky actuation and / or actuation against a drive system (9) of the motor vehicle (2). [10] Motor vehicle (2), comprising a drive system (9) for driving the motor vehicle (2) and a braking system (1) for braking the motor vehicle (2) during a driving operating state of the motor vehicle (2) and for immobilizing the motor vehicle (2) during a parking operating state of the motor vehicle (2), characterized by that the motor vehicle (2) is designed to carry out a method according to one of the preceding claims.

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