DE102019205404A1 - Method for managing a plurality of functions of a brake system, brake system and storage medium - Google Patents

Abstract

The invention relates to a method for managing a plurality of functions of a braking system for a motor vehicle, with different restriction information items being able to be taken into account. The invention also relates to an associated brake system and an associated storage medium.

Description

The invention relates to a method for managing a plurality of functions of a brake system for a motor vehicle, the brake system having an electric motor. The invention also relates to an associated brake system and an associated storage medium.

Nowadays, braking systems are often operated electromechanically, whereby, for example, a braking force applied by the driver can be supported, modulated or a braking force can also be generated separately. Such brake systems are, however, subject to restrictions with regard to the maximum power that they can draw from an on-board network, and also with regard to their own operating state, such as the temperature of various components. Modern brake systems are often designed without a storage medium (power on demand), which exacerbates these restrictions.

Typically, modern brake systems offer a multitude of functions, such as vehicle dynamics control functions, which have different requirements with regard to their power consumption or the load on components.

It is therefore an object of the invention to provide a method for managing a plurality of functions of a brake system for a motor vehicle, which method allows improved or optimal use of the brake system. It is also an object of the invention to provide an associated brake system and an associated storage medium.

This is achieved according to the invention by a method, a braking system and a storage medium in accordance with the respective main claims. Advantageous configurations can be found in the respective subclaims, for example. The content of the claims is made part of the description by express reference.

• - Empfangen einer Anzahl von Einschränkungsinformationen,
• - Ermitteln, basierend auf den Einschränkungsinformationen, welche der Funktionen ausführbar und/oder nur eingeschränkt ausführbar sind, und
• - Freigeben zur Ausführung nur von ausführbaren Funktionen und/oder Deaktivieren von nicht ausführbaren Funktionen und/oder Anpassen von nur eingeschränkt ausführbaren Funktionen.

The invention relates to a method for managing a plurality of functions of a brake system for a motor vehicle, the brake system having an electric motor. The procedure consists of the following steps:

• - receiving a number of restriction information,
• - Determine, based on the restriction information, which of the functions can be executed and / or can only be executed to a limited extent, and
• - Enabling the execution of only executable functions and / or deactivating non-executable functions and / or adjusting functions that can only be executed to a limited extent.

The method according to the invention can be used to determine in a simple manner which functions can be executed or can only be executed to a limited extent, or which functions cannot be executed at all. Accordingly, the functions can be carried out, not carried out or only adapted, i.e. with a restriction, carried out. Such a restriction can relate, for example, to the maximum energy consumption.

It should be understood that the braking system is not limited to having only one electric motor. Several electric motors can also be used, for example in the case of electromechanical brakes. The procedure can be used accordingly.

• - Temperatur des Elektromotors des Bremssystems,
• - Temperatur eines Zwischenkreiskondensators des Bremssystems,
• - Temperatur eines Feldeffekttransistors des Bremssystems,
• - Temperatur von elektrischen, elektronischen oder mechanischen Komponenten des Bremssystems,
• - Spannung eines Fahrzeugbordnetzes,
• - Strombegrenzung, welche über einen Fahrzeugbus erhalten wird,
• - Strombegrenzung, welche als feste Grenze hinterlegt ist,
• - Strombegrenzung, welche aus anderen Einschränkungsinformationen abgeleitet wird.

The restriction information can in particular be selected from the following group:

• - temperature of the electric motor of the braking system,
• - temperature of an intermediate circuit capacitor of the braking system,
• - temperature of a field effect transistor of the braking system,
• - temperature of electrical, electronic or mechanical components of the braking system,
• - voltage of a vehicle electrical system,
• - Current limitation, which is obtained via a vehicle bus,
• - Current limitation, which is stored as a fixed limit,
• - Current limit, which is derived from other restriction information.

It should be understood that any combination of this restriction information item can be taken into account in an implementation, or other restriction information items not mentioned can also be taken into account. By taking into account the temperature of the electric motor or other components, it is possible to react to possible overheating. Such a temperature can be detected, for example, by means of a respective sensor or calculated using a model. It should be mentioned that not only on overheating, but also, for example, on low temperature can be reacted because, for example, an efficiency may be deteriorated because of a cold fat.

By reacting to a voltage in a vehicle electrical system, it is possible, for example, to react to an undervoltage, so that no more power is drawn from the vehicle electrical system. In addition, a corresponding current limit can also be obtained via the vehicle bus, which enables other components of the vehicle to specify the current limit. In this way, for example, a possible overload of the on-board network can be counteracted in good time. It is also possible to derive the current limitation from other restriction information or other information. For example, a table can be stored which, depending on the available voltage, reduces the power consumption in order to keep the vehicle electrical system stable.

The temperature can in particular limit a maximum torque or a maximum phase current of the electric motor. As a result, further overheating of the electric motor can be counteracted in an advantageous manner. A phase current of the electric motor ( 25th ) is limited. A limitation can also be used here which goes beyond an actual mandatory limitation based on the temperature.

The voltage can limit a maximum output of the electric motor, which can reduce the power consumption from an on-board network. The voltage can in particular be the available voltage. The power output can also be limited on the basis of an available voltage. In this case, a limitation can also be used which goes beyond an actual mandatory limitation based on the voltage. The power can be adjusted, for example, according to the currently permitted on-board power supply to be consumed.

On the one hand, the maximum output that can be delivered is reduced by physical restrictions. On the other hand, the output power can be reduced even further. The method according to the invention can in particular serve to configure the overall system in such a way that the reduced output power, which results for example from the current reduction, does not lead to critical situations in the overall system.

• - Antiblockiersystem,
• - Antriebsschlupfregelung,
• - Notbremsassistent,
• - Geschwindigkeitsregelung,
• - autonome Fahrfunktion,
• - Normalbremsfunktion,
• - Fahrdynamikfunktionen, beispielsweise elektronisches Stabilitätsprogramm (ESP), Antriebsschlupfregelung (TCS),
• - Einparkassistent.

The functions can be selected from the following group:

• - anti-lock braking system,
• - Drive slip control,
• - emergency brake assistant,
• - cruise control,
• - autonomous driving function,
• - normal braking function,
• - Driving dynamics functions, e.g. electronic stability program (ESP), traction control (TCS),
• - Parking assistant.

Any combination of these cited functions can be implemented in one implementation, and additional functions or other functions at all can also be implemented.

For example, the maximum output power of the electromechanical actuator can also be limited due to recognized wear of a component. This can be taken into account accordingly. For example, it can be a matter of wear of a ball screw drive or Rot-Trans gear or of a motor bearing, or of reduced magnets that have previously been damaged by excess temperature.

In the step of determining which functions can be carried out, a maximum power and / or a maximum torque of the electric motor is preferably determined as a function of the restriction information. This allows a reliable assignment of which functions can be executed, cannot be executed or can only be executed to a limited extent. For example, a maximum performance in the sense of a working point-dependent performance is also determined for several working points. However, power and torque are also to be understood as a description of a performance, since the associated speed of a motor is typically described with them.

In the step of determining which functions can be carried out, a number of points on an output characteristic curve of the electric motor can be determined as a function of the setting information. This also enables a meaningful assignment of functions which can be executed, cannot be executed or can only be executed to a limited extent.

The step of determining which functions can be carried out can preferably be carried out entirely or partially by software modules and / or hardware modules assigned to the respective function. However, it can also be implemented in other modules or units.

In particular, it is possible to determine which functions can be carried out based on the respective requirement profiles of the functions. These requirement profiles can, for example, be stored in the functions or at another location, for example in a central database.

The electric motor can in particular serve to generate hydraulic pressure in the brake system. However, other uses are also possible. One or more motors can also be provided for electromechanical generation of a braking force, for example in the case of an electromechanical brake, in the case of a partly electromechanical, partly electrohydraulic brake, or in the case of an electrohydraulic brake.

• - Senden von Informationen über ausführbare, nicht ausführbare und/oder nur eingeschränkt ausführbare Funktionen über einen Fahrzeugbus.

According to a development, the method also has the following step:

• - Sending information about executable, non-executable and / or only partially executable functions via a vehicle bus.

This means that other components of a vehicle can be informed about which functions are available, not available or only available to a limited extent. This allows other components to adjust to the current availability of functions.

The invention further relates to a brake system for a motor vehicle with an electric motor and a control device which is configured to carry out a method according to the invention. With regard to the method, all embodiments and variants described herein can be used.

In a system with several motors, for example, the functions can distribute the load in an adapted manner. For this purpose, requests can be limited, for example, on the other hand, in the case of partial load braking, for example, a braking force distribution can be distributed within the framework of the stability limits so that the less restricted drives are used more, for example so that the other drives can cool down.

The invention further relates to a non-volatile computer-readable storage medium which contains program code, when it is executed a processor carries out a method according to the invention. With regard to the method, all embodiments and variants described herein can be used.

Electric motors, especially servomotors and their electronics, are thermally designed for continuous operation, typically for an operating point that is well below the maximum output power. For industrial servos, for example, a factor of 4 is often used. To ensure the protection of the motor and control electronics, the current can be reduced depending on the component temperature of the control electronics or the motor. The output power of the engine is reduced accordingly.

In on-board networks of motor vehicles, there is increasing demand to reduce the power consumption of components depending on the available voltage or the state of the network. In the case of an electrically powered power-on-demand braking system, this also leads to a reduced output power.

Corresponding processes are known as derating. They reduce the available power output in different ways. The system design is therefore typically chosen so that with a maximum reduction in power this is still sufficient for all active functions. However, if the drive continues to heat up due to a limited current reduction, at some point temperature monitoring will switch off the electrical amplification. This can also be referred to as the mechanical fallback level.

In order to increase the availability of the normal braking function, the possible output power or output characteristics should be included in the degradation concept of the vehicle dynamics control systems. Depending on the availability of voltage, battery power and thermal capacity of the drive, different vehicle functions can be available.

To achieve this, several points on a possible output characteristic of the motor can be calculated on the drive side, depending on voltage, current and temperature derating. Based on this, the maximum hydraulic performance can also be calculated. Based on this reported performance, a suitable error management can decide which functions should be shut down or which can only be executed to a limited extent.

To parameterize the deactivation of the functions, the output characteristic curve of the drive can be artificially set or limited by software in a test facility. This functionality can then be used to check which requirements the respective function places on the engine characteristics. This information can then be compared by the fault manager with the available characteristics and functions can be shut down accordingly.

• 1: ein Bremssystem, und
• 2: eine Funktionalität einer Steuerungsvorrichtung.
• 1 zeigt ein Bremssystem 10 gemäß einem Ausführungsbeispiel der Erfindung.

The person skilled in the art will learn further features and advantages from the exemplary embodiment described below with reference to the accompanying drawings. It shows:

• 1 : a braking system, and
• 2 : a functionality of a control device.
• 1 shows a braking system 10 according to an embodiment of the invention.

The braking system 10 has a valve block 20th as well as an electric motor 25th on.

The electric motor 25th is on the valve block 20th attached and used to generate hydraulic pressure in a manner not shown.

The braking system 10 further comprises a control device 30th on which, in a manner not shown, the components of the brake system 10 controls.

On the electric motor 25th is a temperature sensor 27 attached, which is a temperature of the electric motor 25th and to the control device 30th reports. Alternatively, the temperature of the electric motor could also be calculated using a model. The control device 30th also has a vehicle bus interface 35 which enables communication with a vehicle bus. This allows information from other components of the motor vehicle in which the braking system 10 is used.

Both based on the temperature of the electric motor 25th as well as any information received from the vehicle bus, the control device 30th Derive restrictions for the operation of the electric motor 25th and other components of the braking system 10 are relevant. For example, if the electric motor threatens to overheat 25th whose power consumption can be reduced. In the case of a request that is received from a vehicle bus and a power consumption of the brake system 10 should limit a corresponding power consumption of the electric motor 25th be reduced.

The control device 30th In this way, the best possible availability of individual functions of the braking system based on the given operating situation 10 to ensure.

Such functions can be, for example, autonomous driving functions, distance control functions, emergency braking functions or stability functions. These can be activated, restricted or deactivated separately.

2 shows a possible functionality of the control device 30th in greater detail.

A motor control is shown in blocks 31 , an availability management 32 , Functions 33 as well as the vehicle bus interface already mentioned 35 .

The functionalities and information flows are indicated by arrows 40 to 45 shown. The arrow points 40 a flow of availability information such as a characteristic curve. Such information becomes availability management 32 delivered. arrow 41 indicates a possible shutdown of functions. This can be, for example, deactivating or restricting a certain function. arrow 42 indicates a flow of availability information adapted for vehicle functions. Corresponding information can be passed on to a vehicle bus, for example. This allows other units in the vehicle to adjust to the availability or non-availability of functions. The arrows 43 and 44 indicate a respective requirement of functions. This enables corresponding functions via the bus interface 35 and can therefore also be requested by other vehicle components. arrow 45 shows a flow of requirements and limitations, which also go directly from the bus interface to the motor control 31 can be delivered.

Overall, the described and shown embodiment enables an advantageous management of functions in a complex environment and with several variable restrictions to be achieved.

Mentioned steps of the method according to the invention can be carried out in the order given. However, they can also be carried out in a different order if this is technically reasonable. The method according to the invention can be carried out in one of its embodiments, for example with a specific combination of steps, 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 pointed out that features can be described in combination in the claims and in the description, for example to facilitate understanding, although they can also be used separately from one another. The person skilled in the art recognizes that such features can also be combined with other features or feature combinations independently of one another.

References back in subclaims can identify preferred combinations of the respective features, but do not exclude other combinations of features.

Claims (13)

A method for managing a plurality of functions of a brake system (10) for a motor vehicle, the brake system (10) having an electric motor (25), the method having the following steps: - receiving a number of restriction information, - Determine, based on the restriction information, which of the functions can be executed and / or can only be executed to a limited extent, and - Enabling the execution of only executable functions and / or deactivation of non-executable functions and / or adaptation of functions that can only be executed to a limited extent. Procedure according to Claim 1 - The restriction information is selected from the following group: - temperature of the electric motor (25) of the brake system (10), - temperature of an intermediate circuit capacitor of the brake system (10), - temperature of a field effect transistor of the brake system (10), - temperature of electrical, electronic or mechanical components of the braking system (10), - voltage of a vehicle electrical system, - current limitation, which is obtained via a vehicle bus, - current limitation, which is stored as a fixed limit, - current limitation, which is derived from other restriction information. Procedure according to Claim 2 - wherein the temperature limits a maximum torque or a maximum phase current of the electric motor (25) and / or a phase current of the electric motor (25) is limited on the basis of a determined temperature. Method according to one of the Claims 2 or 3 - wherein the voltage limits a maximum power of the electric motor (25) and / or the output power is limited on the basis of an available voltage. Method according to one of the preceding claims, - where the functions are selected from the following group: - anti-lock braking system, - Drive slip control, - emergency brake assistant, - cruise control, - Autonomous driving function, - normal braking function, - driving dynamics functions, - Parking assistant. Method according to one of the preceding claims, - wherein in the step of determining which functions can be executed, a maximum power and / or a maximum torque of the electric motor (25) are determined as a function of the restriction information. Method according to one of the preceding claims, - wherein in the step of determining which functions can be executed, a number of points on an output characteristic curve of the electric motor (25) are determined as a function of the restriction information. Method according to one of the preceding claims, - wherein the step of determining which functions can be carried out is carried out entirely or partially by software modules and / or hardware modules assigned to the respective function. Method according to one of the preceding claims, - whereby, based on the respective requirement profiles of the functions, it is determined which functions can be executed. Method according to one of the preceding claims, - The electric motor (25) is used to generate hydraulic pressure in the brake system (10). Method according to one of the preceding claims, which further comprises the following step: - Sending information about executable, non-executable and / or only partially executable functions via a vehicle bus. A braking system (10) for a motor vehicle, comprising - an electric motor (25), and - A control device (30) which is configured to carry out a method according to one of the preceding claims. Non-transitory computer-readable storage medium which contains program code Execution of a processor a method according to one of the Claims 1 to 11 executes.

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