DE102020216209A1 - Method for temporarily stopping a motor vehicle, braking system and brake torque adjuster - Google Patents

Abstract

The invention relates to a method for temporarily stopping a motor vehicle using a braking system which has a central unit and a plurality of electrical braking torque adjusters. The central unit can activate a temporary hold by means of an activation signal. The invention also relates to a braking system for carrying out such a method and a braking torque adjuster for such a braking system.

Description

The invention relates to a method for temporarily stopping a motor vehicle using a braking system, a braking system for carrying out such a method, and associated braking torque adjusters.

Braking systems are typically used in motor vehicles to brake and/or hold a motor vehicle safely. Typically, a service brake functionality is integrated, which can brake a moving motor vehicle. Furthermore, a locking functionality is typically integrated, which can keep the motor vehicle stationary. The motor vehicle can thus be held reliably for a longer period of time, for example. Typically, today's motor vehicles also have functionalities such as Auto Vehicle Hold or Hill Start Assist, which are aimed at holding the motor vehicle only temporarily. The motor vehicle is not braked while driving, but is not held for a longer period of time as when parked. Rather, it is only held for a short period of time during operation of the motor vehicle, for example while the motor vehicle is at a traffic light or is stopping on a hill to start up again.

While most brake systems have been hydraulically actuated to date, future brake systems are also intended to be electric brake systems. This can either be implemented alone or in addition to a possible hydraulic actuation.

It is an object of the invention to provide a method for temporarily holding a motor vehicle, which is designed as an alternative or better than known designs. Furthermore, the objects of the invention are to provide an associated braking system and associated braking torque adjuster. According to the invention, this is achieved by a method, a braking system and a braking torque adjuster according to the respective main claims.

Advantageous configurations can be found, for example, in the respective dependent claims. The content of the claims is made part of the content of the description by express reference.

• - Senden eines Aktivierungssignals durch die Zentraleinheit an die Bremsmomentensteller, und
• - ansprechend auf einen Empfang des Aktivierungssignals bei jedem der Bremsmomentensteller Erzeugen eines Bremsmoments an der zugeordneten Achsaufnahme.

The invention relates to a method for temporarily stopping a motor vehicle by means of a braking system which has a central unit and a plurality of electrical braking torque adjusters. Each brake torque adjuster is assigned to exactly one axle mount of the motor vehicle. The procedure has the following steps:

• - the central unit sending an activation signal to the braking torque controller, and
• - Responsive to a receipt of the activation signal at each of the brake torque adjusters generating a braking torque at the associated axle.

By means of such a method, an electrically actuated brake system with corresponding electrical brake torque adjusters can be used in a simple manner to implement a temporary holding function of a motor vehicle. It is not necessary to activate parking brake functions such as retracting locking mechanisms. The same components can be used which can also be used to brake a motor vehicle while driving.

Temporary holding is understood to mean in particular holding during operation of the motor vehicle, which is not aimed at longer-term immobilization, such as when parking, for example. Such a temporary stop can occur, for example, when the motor vehicle stops at a traffic light or a starting assistance function is activated when operating on a slope.

An electric braking torque adjuster is in particular a braking torque adjuster which can generate a braking force with the aid of an electromechanical or another electrically operated drive. In particular, it can be provided that such a braking torque adjuster can only be actuated electrically. Alternatively, an additional hydraulic clamping function can also be present.

Typically, an axle mount is understood to mean a mount on which a wheel or a plurality of wheels are rotatably mounted at a specific point on one side of a motor vehicle. If only one wheel is used, one can also speak of a wheel mount. If several wheels are used, this typically corresponds to dual tires. In any case, an axle mount is not to be understood here in such a way that it encompasses a complete axle with wheels on both sides.

The activation signal can in particular be a signal which is specific to a temporary holding function. The central unit is in particular a unit which the motor vehicle before existing electric braking torque adjuster centrally and performs various functions. For example, these can be functions that are described in more detail below. The central unit can also perform other functions and/or can be implemented in a module which can also perform other functions. The transmission can take place in particular via a vehicle bus system or another vehicle-internal communication device. Wireless communication is also possible.

A braking torque is typically generated in such a way that the receipt of the activation signal leads directly to the generation of the braking torque. This is understood to mean that the braking torque is generated in response to receipt of the activation signal.

According to one embodiment, the activation signal can contain braking force information. The braking torque adjusters then typically generate a braking torque as a function of the braking force information. The braking force information can in particular specify how strong the braking force to be generated should be. As a result, different circumstances during operation can be taken into account.

According to one embodiment, the central unit can determine the braking force information as a function of one or more parameters. Such parameters can be, for example, a slope, a load on the vehicle or information about a trailer that may be attached. Accordingly, the central unit can calculate a higher or lower braking force for temporary stopping and display it to the braking torque adjusters, so that different operating situations can be taken into account.

According to one embodiment, one, some or all braking torque adjusters calculate a braking torque to be generated as a function of one or more parameters in response to receipt of the activation signal. The functionality of the central unit described above can thus also be outsourced to the brake torque adjuster. In this case, there is no need for a central calculation. The parameters can typically be supplied to the brake torque adjusters via a vehicle bus system, or they can be determined by them themselves. With regard to possible parameters, reference is made to the statements above.

According to one embodiment, the central processing unit receives wheel speed information from one or more of the axle mounts. This allows the central unit to monitor wheel rotations, which can be used, for example, in the functionalities described below.

For example, immediately after sending the activation signal to all brake torque adjusters, the central unit can send a uniform request for an increase until wheel speed information from all axle mounts is zero. The braking torque adjusters can increase the braking torque, in particular in response to receiving a request for an increase. Using such an embodiment, the braking torque of all braking torque adjusters can be increased centrally in a simple manner until the motor vehicle has safely come to a standstill, in which case the wheel speed information from all axle mounts is used.

According to one embodiment, immediately after the activation signal has been sent, the central unit sends requests for an increase to each brake torque adjuster until wheel speed information for the respectively assigned axle mount is zero. In response to receiving an increase request, the braking torque adjusters increase the braking torque. As a result, the braking force can still be adjusted centrally, but individually for the individual braking torque adjusters. In this way, for example, different load situations can be taken into account and a lower braking force can be used for wheels that do not require a higher braking force.

According to one embodiment, the central unit sends a uniform increase request to all brake torque adjusters in response to wheel speed information that becomes greater than zero during a temporary hold and/or exceeds a threshold value. The braking torque adjusters increase the braking torque in response to receiving an increase request. As a result, during a temporary stop, it can be ensured in a uniform and therefore simple manner that an immediate response is made to a recognized possible rolling away and the vehicle is brought to a standstill again. This may be necessary, for example, if the motor vehicle is standing on a slope and is being loaded during the temporary stop or a trailer is being attached.

According to one embodiment, the central unit sends an increase request to the brake torque adjuster assigned to this axle mount in response to wheel speed information from an axle mount that becomes greater than zero during a temporary stop and/or exceeds a threshold value. The braking torques In response to receiving an increase request, actuators increase the braking torque. As a result, there can also be an immediate reaction to a possible rolling away of the motor vehicle, but this can be done individually for the respective axle mounts and the braking torque can thus be increased in a targeted manner for axle mounts in which a rotation was detected.

An increase in the braking torque can be dependent in particular on the request for an increase. In other words, an increase request can indicate how much the braking torque should be increased. Alternatively, an increase request can also be implemented in such a way that it basically specifies a specific value by which the braking torque is to be increased, so that a corresponding number of increase requests are sent for an increase in the braking torque by a specific value.

According to one embodiment, one, some or all brake torque adjusters receive wheel speed information from their associated axle mount. As a result, functionalities based on wheel speed information can also be implemented directly on the respective braking torque actuators.

According to one embodiment, in response to receiving the activation signal, one, some or all brake torque adjusters directly increase the respectively generated braking torque automatically until wheel speed information of the respectively associated axle mount is zero. As a result, after receiving the activation signal, each brake torque adjuster can ensure that the motor vehicle comes to a standstill and is temporarily held without further cooperation from the central unit. An immediate increase is understood in particular to mean that this increase takes place within the scope of the technical possibilities directly after receipt of the activation signal or at least with only an insignificant delay.

According to one embodiment, one, some or all braking torque actuators increase the braking torque generated in response to wheel speed information from its associated axle mount which becomes greater than zero and/or exceeds a threshold value during a temporary hold. As a result, the functionality already described above with reference to the central unit can be implemented for each individual brake torque adjuster, to react immediately to a changed load and the motor vehicle's resulting rolling away during the temporary stop with an increased braking force, so that the motor vehicle continues to be held . In the embodiment just described, the central unit does not need to be involved.

A braking torque can in particular be increased until wheel speed information and/or all wheel speed information is zero again. This applies in particular both to an increase which emanates from the central unit and an increase which is carried out automatically by the brake torque adjusters. In particular, this relates to an increase during an already active temporary stop, i.e. after a standstill has already been reached, with such an increase being necessary, for example, if the motor vehicle is loaded during the temporary stop or a trailer is attached.

According to one embodiment, it is provided that one, some or all brake torque adjusters generate a brake torque in response to a detected break in communication with the central unit and then temporarily hold the motor vehicle. As a result, it is possible in particular to react immediately to a recognized break in communication with the central unit. Such a break in communication can be detected in an electrically actuated brake system, for example, by the fact that no more expected signals are received on one or two connecting lines between a brake torque adjuster and the central unit, or sent messages are no longer confirmed. In particular, the braking torque can be increased until wheel speed information from an associated axle mount is zero. This functionality can be used, for example, to activate temporary stopping if the motor vehicle is already at a standstill when the communication interruption is detected, or braking from a movement can also take place. In particular, different braking forces can be specified for both cases.

If a temporary hold is activated due to a detected communication break, for example, a transition can be made to a parking brake functionality after a predetermined time, so that the motor vehicle is not only held temporarily, but for an indefinite period of time. For this purpose, for example, a locking mechanism can be activated.

The invention also relates to a braking system for a motor vehicle. The brake system has a central unit and a plurality of electric brake torque adjusters, each brake torque adjuster being assigned to exactly one axle mount of the motor vehicle. The central unit and the brake torque adjusters are used to carry out a method as described herein configured. With regard to the method, all of the versions and variants described herein can be used. Otherwise, reference is made to the explanations and descriptions of variants that were given with reference to the method according to the invention.

In particular, the central unit and/or the brake torque adjusters can have respective control units, which can be designed as programmable or hard-wired units. These can be configured to carry out the method or a relevant part of the method.

The invention also relates to a braking torque adjuster. This can be used in particular for a braking system described herein and/or be configured for use in such a braking system. The braking torque adjuster is configured in particular to calculate a braking torque to be generated as a function of one or more parameters in response to receipt of the activation signal. The brake torque adjuster can also be configured to directly and automatically increase the generated brake system in response to receipt of the activation signal until wheel speed information of the assigned axle mount is zero. The braking torque adjuster can also be configured in particular to increase the braking torque generated in response to wheel speed information from its associated axle mount, which becomes greater than zero during a temporary hold and/or exceeds a threshold value.

The functions already described above with reference to the method according to the invention can advantageously be implemented by means of such a braking torque adjuster. For individual versions and variants, reference is made to the descriptions given with reference to the method according to the invention.

The invention also relates to a braking torque adjuster. This can be used in particular for a braking system described herein and/or be configured for use in such a braking system. The braking torque controller is configured to detect a break in communication with the central unit and to generate a braking torque in response to this. In this way, as already described above with reference to the method according to the invention, it is possible to react advantageously to such a communication interruption and the motor vehicle can be reliably stopped. In particular, a transition can be made to temporary holding, as already described above with reference to the method according to the invention. It can also be switched to a parking brake function. In this regard, reference is made to the above description.

In particular, there can be two connections between a braking torque adjuster and the central unit, with a communication failure only being recognized when communication with the central unit is no longer possible via both connections. This can increase security. If it is recognized that communication via one of the connections is no longer possible, but communication is still possible via the other connection, an error message can be output, for example, which can prompt a driver to visit a workshop. Alternatively, however, only one connection can be used, or more than two connections can also be used.

• 1: ein Bremssystem gemäß einem ersten Ausführungsbeispiel, und
• 2: ein Bremssystem gemäß einem zweiten Ausführungsbeispiel.

The person skilled in the art will find further features and advantages in the exemplary embodiments described below with reference to the attached drawing. show:

• 1 : a brake system according to a first embodiment, and
• 2 : a brake system according to a second embodiment.

1 shows a brake system 5 according to a first embodiment. The braking system 5 has a central unit 10 . This can generally perform monitoring and control tasks. The braking system 5 also has a total of four braking torque adjusters 20 . Each brake torque adjuster 20 is assigned to an axle mount 26, shown purely schematically, with one wheel 28 each in the present case. This corresponds to a typical design of a four-wheel motor vehicle without dual tires.

Each brake torque adjuster 20 has a respective electric motor 21 and a respective control unit 22 . Each electric motor 21 is designed to actuate a respective disk brake 24 , which is shown purely schematically and acts on a respective brake disk 25 . The brake disc 25 can brake the wheel 28 arranged on the axle mount 26 . A respective wheel speed sensor 27 is attached to the axle mount 26 and can sense a wheel speed of the wheel 28 .

In the execution of 1 the wheel speed sensor 27 is connected to the central unit 10 in each case. The central unit 10 is also connected to the respective control units 22 . This allows communication between the central unit 10 and the control units 22. In addition, the central unit 10 receives respective wheel speed signals from the wheel speed sensors 27.

If a motor vehicle in which the brake system 5 is installed is to be held temporarily, the central unit 10 sends an activation signal to the brake torque adjuster 20. At the same time, the central unit 10 starts monitoring the wheel speed information and immediately after the activation signal sends increase requests at fixed time intervals the braking torque adjuster 20. In response to the receipt of an activation signal, each of the braking torque adjusters 20 generates a predefined braking torque by means of its electric motor 21. In response to receiving an increase request, this braking torque is increased in a defined manner. The requests for an increase are sent by the central unit 10 until all the wheel speed information is zero, ie the motor vehicle has come to a standstill.

In an alternative embodiment, the increase requests could also be generated and sent individually for each brake torque adjuster 20, so that they are each sent until the wheel speed information from the respective axle mount 26 is zero.

If one of the wheel speed information becomes greater than zero again during a temporary stop, the central unit 10 sends uniform increase requests to the braking torque adjuster 20 according to one embodiment or, according to an alternative embodiment, sends selective increase requests to the respective assigned braking torque adjuster 20 until the wheel speed information is zero again. As a result, it is possible to react immediately to a possible rolling away of the motor vehicle, for example due to a load or the coupling of a trailer, and the motor vehicle can be reliably held stationary.

2 shows a brake system 5 according to an alternative embodiment. The differences from the first exemplary embodiment are mainly discussed below.

In the brake system 5 according to the second exemplary embodiment, the wheel speed sensors 27 are not connected to the central unit 10, but to the respective control units 22 of the brake torque adjuster 20, as shown. In this case, it is sufficient if the central unit 10 sends an activation signal to all brake torque adjusters 20 in order to activate temporary holding. Each control unit 22 then monitors the corresponding wheel speed signal and automatically increases a braking torque to be generated until the wheel speed signal is zero. As a result, the motor vehicle is held reliably. Should the wheel speed signal become greater than zero during the temporary stop, the respective control unit 22 automatically increases the braking force until the wheel speed signal is zero again.

In order to deactivate the temporary holding, the central unit 10 can send a signal indicating this to the brake torque adjuster 20 in both versions, whereupon the latter reduce the braking force so that the wheels 28 can rotate freely again.

In both exemplary embodiments, the control units 22 can be designed to recognize any communication failure with the central unit 10 . In response to this, they can automatically generate a braking force through the respective electric motor 21, so that a motor vehicle is braked if necessary and is reliably held. This can represent an emergency braking function, in order to prevent the motor vehicle from rolling away in an uncontrolled manner in the event of a fault in the communication or from being unable to be braked from operation.

With the embodiment described here, temporary stopping can be implemented in a simple manner using an electric braking system. When using wheel-specific brake force increases, the load on the brake torque adjuster can be reduced. When using the second embodiment, the signal paths can be shortened and the central processing unit 10 requires less computing capacity.

Mentioned steps of the method according to the invention can be carried out in the order given. However, they can also be executed in a different order, as far as this is technically reasonable. In one of its implementations, for example with a specific combination of steps, the method according to the invention can be carried out in such a way that no further steps are carried out. In principle, however, further steps can also be carried out, including those which are not mentioned.

It should be noted that in the claims and in the description features can be described in combination, for example to facilitate understanding, although they can also be used separately. Those skilled in the art will recognize that such features may also interact independently with others Features or combinations of features can be combined.

Back-references in dependent claims can identify preferred combinations of the respective features, but do not exclude other combinations of features.

Reference List

5

braking system

10

central unit

20

brake torque adjuster

21

electric motor

22

control unit

24

disc brake

25

brake disc

26

axle mount

27

wheel speed sensor

28

wheel

Claims (17)

Method for temporarily stopping a motor vehicle by means of a braking system (5) which has a central unit (10) and a plurality of electric brake torque adjusters (20), each brake torque adjuster (20) being assigned to exactly one axle mount (26) of the motor vehicle, the method has the following steps: - Sending an activation signal by the central unit (10) to the brake torque adjuster (20), and - In response to receipt of the activation signal at each of the braking torque adjusters (20) generating a braking torque at the associated axle mount (26). procedure after claim 1 - wherein the activation signal contains braking force information, and - wherein the braking torque adjuster (20) generate a braking torque as a function of the braking force information. procedure after claim 2 - Wherein the central unit (10) determines the braking force information as a function of one or more parameters. Method according to one of the preceding claims, - wherein one, some or all brake torque adjusters (20) calculate a braking torque to be generated in response to receipt of the activation signal as a function of one or more parameters. Method according to one of the preceding claims, - Wherein the central unit (10) receives wheel speed information from one or more of the axle mounts (26). procedure after claim 5 , - wherein the central unit (10) immediately after sending the activation signal to all brake torque adjusters (20) sends a uniform increase request until wheel speed information from all axle mounts (26) is zero, - wherein the brake torque adjusters (20) respond to the receipt of an increase request braking torque raise. Procedure according to one of Claims 5 or 6 , - wherein the central unit (10) sends requests for an increase to each brake torque adjuster (20) immediately after the activation signal has been sent, until wheel speed information for the respectively assigned axle mount (26) is zero, - wherein the brake torque adjusters (20) increase the braking torque in response to receiving an increase request raise. Procedure according to one of Claims 5 until 7 , - wherein the central unit (10) sends a uniform increase request to all brake torque adjusters (20) in response to wheel speed information which becomes greater than zero during a temporary stop and/or exceeds a threshold value, and - wherein the brake torque adjusters (20) respond to the Receiving an increase request increase the braking torque. Procedure according to one of Claims 5 until 8th - the central unit (10) responding to wheel speed information from an axle mount (26) which becomes greater than zero during a temporary stop and/or exceeds a threshold value, sending an increase request to the brake torque adjuster (20) assigned to this axle mount (26), and - wherein the braking torque adjusters (20) increase the braking torque in response to receiving an increase request. Method according to one of the preceding claims, - Wherein one, some or all brake torque adjusters (20) receive wheel speed information from their associated axle mount (26). procedure after claim 10 - wherein one, some or all brake torque adjusters (20) directly increase the respectively generated braking torque automatically in response to receipt of the activation signal until wheel speed information of the respectively assigned axle mount (26) is zero. Procedure according to one of Claims 10 or 11 - wherein one, some or all brake torque adjusters (20) increase the brake torque generated in response to wheel speed information from its associated axle mount (26) which becomes greater than zero during a temporary hold and/or exceeds a threshold value. Procedure according to one of Claims 8 , 9 or 12 - A braking torque being increased until wheel speed information and/or all wheel speed information is zero again. Method according to one of the preceding claims, - Wherein one, some or all brake torque adjusters (20) generate a brake torque in response to a detected break in communication with the central unit (10) and then temporarily hold the motor vehicle. Braking system (5) for a motor vehicle, - having a central unit (10) and a plurality of electric brake torque adjusters (20), each brake torque adjuster (20) being assigned to precisely one axle mount (26) of the motor vehicle, - Wherein the central unit (10) and the braking torque adjuster (20) are configured to carry out a method according to any one of the preceding claims. Braking torque adjuster (20) for a braking system (5). claim 15 - wherein the braking torque adjuster (20) is configured to calculate a braking torque to be generated as a function of one or more parameters in response to receipt of the activation signal; and/or - wherein the brake torque adjuster (20) is configured, in response to receipt of the activation signal, to automatically increase the brake torque generated immediately until wheel speed information of the associated axle mount (26) is zero; and/or - wherein the braking torque adjuster (20) is configured to increase the braking torque generated in response to wheel speed information from its associated axle mount (26) which becomes greater than zero during a temporary hold and/or exceeds a threshold value. Braking torque adjuster (20) for a braking system (5). claim 15 - Wherein the braking torque controller (20) is configured to detect a break in communication with the central unit (10) and to generate a braking torque in response thereto.

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