Vehicle brake device and method for operating vehicle brake device

Abstract

The invention provides a brake device (10) for a vehicle (F), comprising a control device (SE) coupled to a brake actuator device (BA), the control device (SE) being arranged for detecting an operating state of an electric machine (EM) in generator operation and a second brake torque generateable by the electric machine (EM) and for operating the brake actuator device (BA) in dependence on the operating state of the electric machine (EM) in generator operation, in which at least a predetermined total brake torque can be generated on the vehicle (F) as a sum of the second brake torque of the electric machine and a first brake torque of the brake actuator device (BA), the control device (SE) being further arranged for decreasing or increasing the generated first brake torque of the brake actuator device (BA) in order to maintain a predetermined value range of an operating parameter of the brake actuator device (BA) and / or in order to provide at least the predetermined total brake torque together with the second brake torque on the vehicle (F).

Description

[Technical Field]

[0001] The present invention relates to a vehicle brake system and a method for operating a vehicle brake system. [Background technology]

[0002] A typical drive concept in an electrically operated vehicle can rely on an electric machine for braking. For this purpose, brake force generators or brake boosters are known that can be electronically activated when braking is required. In special circumstances, such as when the temperature rises or the voltage increases or decreases, these devices can be downgraded. In this case, downgrading can be a limitation of their usefulness.

[0003] Despite the downgrade, use is possible if the default for braking action can be achieved at least partially.

[0004] In its operational state, the brake actuator may be either fully functional, downgraded by some predetermined operating minimum, or shut down completely.

[0005] In the patent application WO 02 / 044949 a method for operating a creep mode in a motor vehicle is described. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] German Patent Application Publication No. 102016201348A1 Summary of the Invention

[0007] The present invention provides a vehicle brake device as set forth in claim 1 and a method for operating a vehicle brake device as set forth in claim 5 .

[0008] Advantageous further configurations are the subject of the dependent claims.

[0009] The basic idea of ​​the present invention is to provide a vehicle brake system and a method for operating a vehicle brake system, which allows for increased availability of the brake actuator system, by taking into account the operating state of the brake actuator system, by utilizing the braking torque provided by the generator and by adjusting the operation of the brake system in such a way as to extend the service life of the brake actuator system.

[0010] In this case, it is advantageous to take into account the current power capacity of the electric machine as a generator, in terms of its availability. This can be taken into account when selecting a downgrade of the operation of the brake actuator device. Note that the term "downgrade" can refer to any perceptible inhibition or reduction that may occur in the operation or function of the brake actuator device and / or other components in the vehicle. In this case, the deceleration component (component of the brake torque) contributed by the generator can be taken into account, and additionally, the brake actuator can be downgraded.

[0011] According to the present invention, a vehicle brake system capable of controlling the braking action of a vehicle includes a brake actuator device and a control device coupled to and / or included in the brake actuator device, the control device being further coupled to an electric machine of the vehicle and being arranged to detect an operating state of the electric machine in generator operation and a second brake torque generateable by the electric machine, and to operate the brake actuator device depending on the operating state of the electric machine in generator operation, and being able to generate at least a predetermined total brake torque for the vehicle as the sum of the second brake torque of the electric machine and a first brake torque of the brake actuator device, and the control device being further arranged to detect and vary at least one operating parameter for operation of the brake actuator device, thereby reducing or increasing the generated first brake torque of the brake actuator device, in order to maintain a predetermined value range of the operating parameter and / or to provide at least the predetermined total brake torque together with the second brake torque to the vehicle.

[0012] Braking may be a braking process in a vehicle to slow down the rotation of the wheels, for example with a friction braking torque and / or a braking torque by an electric generator and / or any other type of braking force for a vehicle.

[0013] In this case, the deceleration can be obtained or achieved according to a default in the vehicle, where the default can be selected by the user to be low or high (strong). The brake actuator device can be any type of friction brake or any other type of normal brake or other brake that is not based on a generator.

[0014] In this case, the operating state of the electric machine as a generator can be determined, which corresponds to how much generator braking torque the electric machine can currently or generally provide, for example, for a given speed range at a specific driving performance, at a specific temperature, at an assessable available battery charge / power, and at further operating-specific parameters for the electric vehicle. Depending on the knowledge of the output capacity of the electric machine as a generator and thus as a device for generating a generator braking torque, it is then possible, for example, to adaptively and dynamically increase and / or decrease the first braking torque over time to partially reach a minimum braking torque default that is always available for the vehicle and can be, for example, the sum of the first braking torque and the second braking torque, or the minimum braking torque defaults of the individual braking torques.

[0015] The operating parameters for the operation of the brake actuator devices to be detected and changed for this purpose may be various parameters that are important for the operation of each of these brake actuator devices, and to this operating parameter or parameters, corresponding value ranges or values ​​may be associated that may be necessary to arrive at a default with approximately constant tolerances, in order to at least partially obtain a default for the braking action.

[0016] In this case, it is advantageous to take into account the generator output capacity for downgrading one brake actuator. In other words, it is possible to assess to what extent the generator can provide a default total brake torque for the vehicle, and whether it can always provide it, or whether it can provide it in the current (to be assessed) situation, and to what extent the first brake torque can be reduced at this time. Reducing the first brake torque in this way can change one or more specific operating parameters of the brake actuator device, for example, to reduce the first brake torque and reduce the operating load of the brake actuator device. This can advantageously occur so that the default total brake torque can be at least partially met again. This default can be set as a standard value by the vehicle manufacturer and / or the current user. It is available for all brake actuators that allow active downgrading.

[0017] The available generator power capacity may be limited by various parameters, such as the state of charge of the battery or the speed of the vehicle. For this reason, the downgrade must be continuously adjusted taking into account the generator power capacity so that it is adapted to the current generator power capacity at each time.

[0018] For example, the so-called "service brake performance" may be set, i.e. 6.43 m / s with a pedal force of 500 N. 2 The stronger the downgrade, the better the availability.

[0019] By taking the generator rate into account in this way, the requirements for the minimum operating mode of the brake actuator can be reduced. In this case, it may be necessary for the brake actuator to know the current available power output of the generator. If the brake actuator is not responsible for controlling the generator and the control device is not directly attached to or located in the generator, the available power output of the generator can be communicated to the brake actuator via an existing communication network (CAN, FlexRay, etc.). If the default "service brake performance" is used as the minimum operating mode, the brake actuator can be set to, for example, 3 m / s 2 The generator's available power output at a deceleration of 6.43 m / s 2 but 3.43 m / s 2 (with a pedal force of 500N).

[0020] The vehicle may be a passenger car equipped with a drive unit which may include an electric machine.

[0021] According to an advantageous embodiment of the brake device, the brake actuator device comprises a brake booster and / or a brake system.

[0022] The braking system may include friction brakes or may include various other non-dynamo brakes.

[0023] According to an advantageous embodiment of the brake device, the control device is connectable to an on-board power grid of the vehicle and is arranged to detect an on-board power grid voltage, compare it with a default value and reduce the first brake torque, in which case the first brake torque is reduced by reducing a drive voltage and / or a drive current of a brake actuator device in the vehicle when the on-board power grid voltage drops below a first threshold value.

[0024] If the voltage drops below a first threshold, the current consumption of the brake actuator can be limited, thereby preventing further voltage downgrades due to current flow. If the voltage still drops below a second threshold, the brake actuator can be completely shut down. To this end, the default value can correspond to a full voltage or a minimum value for the operating mode of the onboard power grid, for example 12 V or 6 V, or to the first or second threshold.

[0025] In this case, the first and / or second threshold values ​​can be used as default values.

[0026] The first threshold value may be, for example, 6 V, and in this case, if the default for the full brake torque can still be achieved, the first brake torque may be reduced to a predetermined magnitude. The drive voltage and / or drive current of the brake actuator device may then be such that the first brake torque is generated. This reduced voltage or current utilization may result in a lower current or voltage load on the onboard power grid. This reduces the operating current required (to be provided) for the brake actuator to operate. This reduces the load on the onboard power grid generated for the downgraded brake actuator. Additionally, since the downgraded state requires less power consumption, the second threshold value may be selected to be even smaller. In this case, the operating range extends down to lower voltages.

[0027] According to an advantageous embodiment of the brake system, the brake actuator device comprises a temperature sensor by means of which the operating temperature of the brake actuator device can be detected, in which case the control device is coupled to the temperature sensor and is arranged to compare the operating temperature with a default value for temperature and to operate the brake actuator device depending on the operating temperature.

[0028] In the case of an excessive temperature, which can be detected by a temperature sensor, further heating of the brake actuator (and possibly shutting down the brake actuator when the shutdown temperature is exceeded) can be prevented by downgrading. A default value for the temperature can then be a predetermined temperature that is to be tolerated further or can already correspond to the shutdown temperature. The brake actuator device can then be controlled depending on this default value, in which case the first brake torque can be reduced, for example, if the default value and / or tolerance for the temperature is exceeded.

[0029] A reduction in minimum power output may reduce the thermal load at the point of downgrading. As a result, the available temperature range may be extended without downgrading. Alternatively or additionally, the serviceability may be increased up to continuous operating capability within the downgraded range.

[0030] The minimum power determines how much the current consumption of the device can be limited. The current consumption can also be responsible for the temperature rise. Downgrading to a lower current consumption will result in a lower temperature rise in the downgraded state. If, for example, there is a specific (final) shutdown threshold and the design objective is to reach this threshold only after a certain time has passed, the device can be moved to the downgraded state at an earlier threshold. Due to the lower current of the present invention, the temperature rise in the downgraded state can also be slower, so the downgrade threshold can be selected higher.

[0031] The same is true for sustained operation. Sustained operation exists when the shutdown threshold can never be reached. This is the case when the specified maximum ambient temperature plus the temperature rise due to operation in a downgraded state is less than the shutdown threshold. If the temperature rise in the downgraded state is relatively small, temperatures higher than the maximum ambient temperature are possible, or, if the specification is constant, conditions may improve such that a system that would otherwise be incapable of sustained operation suddenly becomes capable of sustained operation.

[0032] According to the present invention, a method for operating a vehicle brake system for controlling the braking action of a vehicle includes recognizing the need to perform a braking action using the brake system of the present invention, detecting the operating state of the electric machine in generator operation and a second brake torque that can be generated in the electric machine from this, comparing this second brake torque that can be generated with a predetermined total brake torque for the vehicle, and generating a total brake torque for the vehicle by combining a first brake torque by the brake actuator system and the second brake torque by the electric machine, and in this case adjusting operating parameters for operating the brake actuator system, thereby reducing or increasing the first brake torque of the brake actuator system, thereby providing at least the predetermined total brake torque to the vehicle together with the second brake torque.

[0033] The need can be recognized from the driver's pedal operation or by a sensor device provided in the vehicle, which may include driver commands and / or traffic conditions.

[0034] The predetermined total braking torque may be at least the braking torque to be obtained or as necessary for the current situation.

[0035] According to an advantageous embodiment of the method, at least one operating parameter for the operation of the brake actuator device is detected and changed, thereby reducing the first brake torque of the brake actuator device, while maintaining a predetermined value range of the operating parameter.

[0036] According to an advantageous embodiment of the method, the currently maximum possible second braking torque is determined and the first braking torque is reduced as long as the predetermined total braking torque at the vehicle is still available.

[0037] A detection of a currently available second braking torque may be performed and / or an assessment of a second braking torque that may be available in the near future may be made.

[0038] According to an advantageous embodiment of the method, the voltage and / or current in the on-board power supply network of the vehicle is detected to reduce the first brake torque, in which case the drive voltage and / or drive current of a brake actuator device in the vehicle is reduced in order to reduce the first brake torque.

[0039] A general adaptation to the drive voltage and / or drive current may be performed.

[0040] According to an advantageous embodiment of the method, the voltage in the on-board power supply network is detected, and if the voltage in the on-board power supply network drops below a first threshold, the drive voltage and / or drive current of the brake actuator device is limited, and if the voltage in the on-board power supply network drops below a second threshold, the brake actuator device is shut down when a second brake torque reaches a predetermined total brake torque in the vehicle itself.

[0041] If the voltage drops below a first threshold, the current consumption of the brake actuator is limited. This prevents further voltage downgrades due to current flow. Nevertheless, if the voltage drops below a second threshold, the brake actuator may be completely shut down. This may reduce the operating current required for the brake actuator to operate. This reduces the load on the onboard power grid caused by the downgraded brake actuator. In addition, since a lower power consumption is required in the downgraded state, the second threshold can also be selected to be lower. Here, the operating range is extended down to lower voltages.

[0042] According to an advantageous embodiment of the method, the operating temperature of the brake actuator device is detected by a temperature sensor and the first brake torque is reduced if the operating temperature exceeds a predetermined value.

[0043] According to an advantageous embodiment of the method, the operating state of the electric machine and the second braking torque of the electric machine which can be generated from this are detected either continuously or at predetermined time intervals.

[0044] The braking system may also feature the features and advantages of the method mentioned in connection with the method, and vice versa.

[0045] Further features and advantages of embodiments of the present invention will become apparent from the following description, which refers to the accompanying drawings.

[0046] The invention will now be explained in more detail on the basis of an embodiment illustrated in the schematic diagram of the drawing. [Brief explanation of the drawings]

[0047] [Figure 1] 1 is a schematic diagram of a vehicle brake device according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram of a braking system according to an embodiment of the present invention in a vehicle; [Figure 3] 1 is a block diagram of method steps of a method for operating a vehicle brake system according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0048] In the figures, the same reference numbers represent the same components or components with the same functions.

[0049] FIG. 1 is a schematic diagram of a vehicle brake device according to an embodiment of the present invention.

[0050] A vehicle brake device 10 capable of controlling the braking action of a vehicle F comprises a brake actuator device BA and a control device SE coupled to and / or included in the brake actuator device BA, wherein the control device SE is further coupled to an electric machine EM of the vehicle F and is configured to detect an operating state of the electric machine EM in generator operation and a second brake torque generateable by the electric machine EM, and to operate the brake actuator device BA depending on the operating state of the electric machine EM in generator operation, wherein the control device SE is capable of generating at least a predetermined total brake torque for the vehicle F as the sum of the second brake torque of the electric machine and the first brake torque of the brake actuator device BA, and the control device SE is further configured to detect and vary at least one operating parameter for operating the brake actuator device BA, thereby reducing or increasing the generated first brake torque of the brake actuator device BA, in order to maintain a predetermined value range of the operating parameter and / or to provide at least the predetermined total brake torque together with the second brake torque to the vehicle F.

[0051] FIG. 2 is a schematic diagram of a braking system in a vehicle according to one embodiment of the present invention.

[0052] FIG. 2 illustrates further components and the interconnections between these components that may be provided in addition to or alternatively to the embodiment of FIG.

[0053] To this end, the brake system 10 may be embodied such that the control device SE is connectable to the on-board power supply network BN of the vehicle and is arranged to detect the on-board power supply network voltage, compare it to a default value, and reduce the first brake torque, whereby the first brake torque is reduced by reducing the drive voltage and / or drive current of the brake actuator device BA in the vehicle when the on-board power supply network voltage drops below a first threshold value. The brake actuator device BA may include a temperature sensor TS, and / or the control device SE may be coupled to the temperature sensor TS, by means of which the operating temperature of the brake actuator device BA may be detected, whereby the control device SE is arranged to compare the operating temperature with a default value for the temperature and to activate the brake actuator device depending on the operating temperature.

[0054] The brake actuator device BA may include a pedal sensor PS and / or the control device SE may be coupled to a pedal sensor PS by means of which the brake request may be recognized.

[0055] FIG. 3 is a block diagram of method steps of a method for operating a vehicle brake system according to one embodiment of the present invention.

[0056] A method for operating a vehicle brake device includes recognizing (S1) the need to perform a braking action using the brake device of the present invention, detecting (S2) the operating state of the electric machine during generator operation and the second brake torque that can be generated in the electric machine from this, and comparing this second brake torque that can be generated with a predetermined total brake torque in the vehicle, and (S3) generating a total brake torque in the vehicle by combining the first brake torque by the brake actuator device and the second brake torque by the electric machine, in which case operating parameters for operating the brake actuator device are adjusted, thereby reducing or increasing the first brake torque of the brake actuator device, thereby providing at least the predetermined total brake torque to the vehicle together with the second brake torque.

[0057] While the present invention has been fully described with reference to preferred embodiments thereof, it is not limited thereto and can be modified in various ways and aspects. [Explanation of symbols]

[0058] 10 Brake device BA Brake Actuator Device EM Electrical Machine F vehicle SE control device S1 Steps to recognize the need to apply braking action S2: Comparing the second brake torque with the total brake torque S3 Step to generate full braking torque

Claims

1. A vehicle brake device (10) capable of controlling the braking action of a vehicle (F), a brake actuator device (BA), a control device (SE) coupled to and / or included in said brake actuator device (BA), said control device (SE) being further capable of being coupled to an electric machine (EM) of said vehicle (F) and being arranged to detect the operating state of said electric machine (EM) in generator operation and a second brake torque that can be generated by said electric machine (EM), and to activate said brake actuator device (BA) depending on the operating state of said electric machine (EM) in generator operation, and being able to generate at least a predetermined total brake torque on said vehicle (F) as the sum of said second brake torque of said electric machine and a first brake torque of said brake actuator device (BA), the control device (SE) is connectable to an on-board power grid of the vehicle and detects an on-board power grid voltage, and reduces the first brake torque by reducing a drive voltage and / or a drive current of the brake actuator device (BA) in the vehicle when the on-board power grid voltage drops below a first threshold; shutting down the brake actuator device (BA) when the second brake torque reaches the predetermined total brake torque of the vehicle (F) if the on-board power grid voltage drops below a second threshold value lower than the first threshold value; Braking device (10).

2. The brake device (10) of claim 1, comprising the brake actuator device (BA) and a brake booster device (BV).

3. A brake device (10) as described in claim 1 or 2, characterized in that the brake actuator device (BA) includes a temperature sensor by which the operating temperature of the brake actuator device (BA) can be detected, and the control device (SE) is coupled to the temperature sensor and is configured to compare the operating temperature with a default value for temperature and operate the brake actuator device depending on the operating temperature.

4. A brake actuator device (BA), a control device coupleable to an electric machine of a vehicle and configured to detect an operating state of the electric machine in generator operation and a second brake torque generateable by the electric machine, and to operate the brake actuator device in dependence on the operating state of the electric machine in generator operation, the control device generating at least a predetermined total brake torque on the vehicle as a sum of the second brake torque of the electric machine and a first brake torque of the brake actuator device, - a step (S1) of recognizing the need to perform a braking action using said braking device (10); a step (S2) of detecting the operating state of the electric machine (EM) during the generator operation and a second brake torque that can be generated by the electric machine (EM) from this, and comparing this second brake torque with a predetermined total brake torque of the vehicle (F); - generating (S3) a total braking torque on the vehicle (F) by combining the first braking torque by the brake actuator device (BA) and the second braking torque by the electric machine (EM); - detecting the voltage and / or current in the on-board power supply network of the vehicle (F) and reducing the first brake torque, in which case the drive voltage and / or drive current of the brake actuator device (BA) in the vehicle is reduced in order to reduce the first brake torque; - limiting the drive voltage and / or drive current of the brake actuator device (BA) if the voltage in the on-board power supply network of the vehicle (F) drops below a first threshold value, and shutting down the brake actuator device (BA) if the voltage in the on-board power supply network drops below a second threshold value lower than the first threshold value, when the second brake torque reaches the predetermined total brake torque of the vehicle (F) itself; The method of operation includes:

5. A method as described in claim 4, wherein the operating temperature of the brake actuator device (BA) is detected by a temperature sensor, and if the operating temperature exceeds a predetermined value, the first brake torque is reduced.

6. A method as described in claim 4 or 5, wherein the operating state of the electric machine (EM) and the second braking torque in the electric machine (EM) that can be generated from this are detected constantly or at predetermined time intervals.

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