KR20170068397A - Brake system for a vehicle, method for operating a brake system and vehicle with such a brake system - Google Patents

Abstract

The present invention relates to a brake system (1) for a vehicle (3) having a brake booster (5) and an electronic braking force distribution system (7), wherein the brake booster (5) and the electronic braking force distribution system Are connected to each other via a communication link (11). In this case, a second communication link 13 different from the first communication link 11 is provided between the brake booster 5 and the electromagnetic braking force distribution system 7, The first information on the state of the vehicle 5 and the second information on the driver's braking demand of the vehicle 3. [

Description

Technical Field [0001] The present invention relates to a vehicle brake system, a method of operating the brake system, and a vehicle having the brake system of the above type. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a vehicle brake system, a method of operating the brake system, and a vehicle having the brake system of the above type.

This type of braking system particularly comprises a brake booster and an electronic braking force distribution system, wherein the brake booster and the electronic braking force distribution system are interconnected via a first communication link. The brake booster is configured to increase the braking force of the vehicle driver so as to increase the hydraulic pressure generated by the driver, particularly in the brake master cylinder. The brake booster, when required by the function of the vehicle, can form autonomously - without the driver's action - pressure.

An electronic braking force distribution system, particularly an ESP system (electronic stabilization program), is configured to distribute braking pressures provided by the driver and / or brake booster to individual brake pistons that are separately assigned to the wheels of the vehicle. In this case, it is also possible to separately allocate the braking pressure and, consequently, the braking pressure specific to the wheel, and the braking effect inherent in the wheel. Preferably, the electronic braking force distribution system is also configured to be capable of forming hydraulic pressure, in particular braking pressure, actively - in particular independent of the brake booster. The electronic braking force distribution system is preferably integrated or implemented within an engine control unit (ECU) of the vehicle.

The first communication link is preferably configured as a CAN connection or a Flexray connection.

When the brake booster fails, the increase of the braking force is stopped, which can be preferably compensated by the electronic braking force distribution system. In this case, the driver can form an unenhanced pressure in the brake master cylinder through the operation of the brake pedal of the vehicle. This pressure, as measured by the electronic braking force distribution system, is proportional to the driver ' s braking demand and can be used as an adjustment parameter for active pressure generation through the electronic braking force distribution system. Thus, at such failure replacement level, the braking force is augmented by the electronic braking force distribution system. However, the hydraulic braking force compensation through the electronic braking force distribution system needs to be improved. Since the brake master cylinder pressure is used as a regulating variable, the braking force support can be performed only when the driver forms a pressure in the brake master cylinder. In the absence of an active brake booster, the force required by the driver to create pressure in the brake master cylinder is typically significantly higher than if the active brake booster were present. Therefore, a high initial force is required to achieve the braking effect.

Further, when the first communication link is interrupted, there is no information about the state of the brake booster in the electronic braking force distribution system. That is, it is unknown whether the brake booster can still meet its enhanced function. In this situation, based on the brake master cylinder pressure, when braking pressure buildup is carried out by the electronic braking force distribution system, this leads to at most a doubling of the driver braking demand, State. On this basis, in the event of a communication failure, the reduction of the braking force enhancement is usually performed by the electronic braking force distribution system, so that a doubling of the braking force can be allowed if necessary.

It is an object of the present invention to improve the brake system of a vehicle so that the brake system of the above type has improved characteristics and in particular does not have the disadvantages mentioned above. It is also an object of the present invention to provide a vehicle having a brake system operating method and correspondingly improved brake system.

This problem is solved by providing an object of independent claims. Preferred configurations are set forth in the dependent claims.

According to the present invention, a second communication link, different from the first communication link, is provided between the brake booster and the electronic braking force distribution system, the second communication link comprising first information on the state of the brake booster, To transmit the second information. Thus, when the first communication link fails, not only the state of the brake booster but also the braking demand of the driver can be reliably transmitted from the brake system to the electromagnetic braking force distribution system, so that reliable information always available in the electromagnetic braking force distribution system do. Thereby, the double reinforcement or the braking force reduction reduction can be prevented, and at the same time, the initial force for the driver to achieve the braking effect can be achieved.

A communication link means, in particular, a connection through which information and / or data can be conveyed over the communication link. This is preferably an electrical or electronic working connection. The communication link may have a single communication channel or a plurality of communication channels, particularly in the form of a single signal line or a plurality of signal lines. However, wireless communication links with one or more communication channels, for example wirelessly, in particular via Bluetooth or WLAN, or via an optical interface, for example an infrared interface, are also possible. Fiber optic links can also be considered.

The second communication link is particularly configured to be independent of the first communication link. This ensures the function of the second communication link even in the event of a failure of the first communication link.

The second communication link is preferably configured to transmit the first information and the second information entirely. That is, the second communication link is particularly preferably not used for the transmission of other additional information and / or data.

Here, the state of the brake booster particularly means whether the brake booster is ready for operation, that is, whether or not the brake booster is operable. Preferably, via the brake booster, binary information on whether the brake booster is operable is transmitted.

Here, the driver braking demand usually means that the driver is willing to brake - in particular through the actuation of the brake pedal. Preferably, the braking demand means binary information that indicates whether or not the driver will signal the braking demand. Therefore, according to a preferred configuration of the present invention, it is not important how much the braking demand of the driver is quantitatively insufficient. Rather, it can be calculated without problems, especially based on the pressure created in the brake master cylinder by the driver.

The driver's braking demand is preferably detected using braking demand recognition means integrated or implemented in the brake booster. Thus, the braking demand of the driver can be transmitted from the brake booster via the second communication link, in particular from the braking demand recognition means, to the electronic braking force distribution system.

Preferably, the second communication link can operate independently of the controller of the brake booster, in particular the microcontroller of the brake booster. The second communication link transmits information on the state of the brake booster and information on the driver's braking demand, preferably regardless of the state of the control device of the brake booster.

Based on the first and second information, the electronic braking force distribution system can determine whether enhancement via the brake booster is provided, even in the event of a failure of the first communication link, also referred to as the main communication link. This can eliminate the problem of dual buildup in the case of an operable brake booster, or the problem of unnecessary reduction in the case of a faulty brake booster. In addition, the second information about the driver's braking demand can be used to initialize the braking force enhancement via the electronic braking force distribution system earlier, i.e., at a lower pedal force. For example, through targeted pressure build-up using an electronic braking force distribution system, a reduction in initial force can be achieved at the driver's comfortable pedal feel.

According to an improvement of the invention, the second communication link has a first communication channel for transmission of the first information, and a second communication channel for transmitting second information, which is different from the first communication channel. Preferably, such communication channels are independent of each other. In particular, it is also possible that the first information and the second information are transmitted from the brake booster to the electromagnetic braking force distribution system via respective separate lines. In particular, such information is preferably transmitted as two independent signal lines as a signal. This has the advantage that the second communication link can be implemented very simply in terms of technology.

According to an improvement of the present invention, the second communication link has a communication channel configured for transmission of the first and second information. Particularly preferably, the second communication link has exactly one communication channel for the first information and the second information. That is, the first information and the second information are preferably transmitted over exactly one communication channel. In particular, the information is preferably transmitted over a single line, and the information preferably can carry more than two states. Preferably, in this configuration, only one communication channel, in particular only one line, is needed to couple the brake booster with the electronic braking force distribution system. Thus, such a configuration is very inexpensive and less susceptible to failure.

According to an improvement of the present invention, the second communication link has a drive device configured to drive the communication channel irrespective of the combination of the first information and the second information. This is particularly the case when the second communication link has exactly one single communication channel for transmitting two pieces of information. By using the driving device, a so-called superposition of two pieces of information can be generated and transmitted through one communication channel. In particular, the drive is preferably configured to generate various states for the communication channel from the two pieces of information - according to their current value. Basically, two binary signals can be combined into four states. Signal transmission via a single communication channel, as described herein, preferably enables the function to be used only when the brake booster is in a disabled state. Therefore, in the case of the operable brake booster, it is not necessary to continually determine whether or not the driver signals the current braking demand. Thus, the number of states to be transmitted is reduced to three as follows:

(a) the brake booster is operational;

(b) the brake booster is inoperable and the driver does not signal the braking demand;

(c) a state in which the brake booster is inoperable and the driver signals a braking demand;

At this time, in state (a), it is not important whether the driver signaling the braking demand - as described previously.

The drive is particularly adapted to generate the three states described herein from the corresponding binary values for the first information and the second information and to generate in the communication channel signals assigned corresponding to one of these states.

According to an improvement of the invention, the second communication link has a current interface, a voltage interface, or a PWM interface. In this case, the current interface means an interface configured to transmit a specific value or state through the setting of a specific current, particularly a predetermined current value. The voltage interface means an interface configured to transmit a value or a status through the setting of a specific voltage. The PWM interface means an interface configured to transmit a pulse width modulated signal. In this case, it is also possible, in particular, to carry out a specific time-averaging of the specific current or the specific voltage - correspondingly via the pulse width modulation signal. The interfaces referred to herein are meant to be a simple, economical and useful possibility for transmitting information and / or data.

According to an improvement of the present invention, various values of the first information and / or the second information are assigned various current values and / or various voltage values of the second communication link. In this case, the value of the information means, in particular, which binary state each information takes, i.e. a query as to whether the brake booster is operable in the case of the first information, And a query as to whether or not to signal the signal. Particularly preferably, various voltage values of the second communication link and in particular of a single communication channel are assigned to the various values and / or combinations of these values, in particular in terms of overlapping.

If the second communication link has two communication channels, i. E. A separate communication channel for each piece of information, the voltage signal is preferably "disabled" when transmitting information on whether the brake booster is operational Is used in such a manner that a voltage of 0 V is used. In this case, the signal is correct even in the case of a voltage failure that interferes with the function of the brake booster. The evaluation of the separately transmitted information is preferably performed in the controller of the vehicle.

In the case of a second communication link having exactly one single communication channel for two pieces of information, preferably a voltage interface is used in which the voltage can vary between 0V and 12V. Preferably, three different specific voltage values, particularly preferably three voltages 0V, 6V and 12V, are used for the three states (a), (b) and (c) described above. In this case, at state 0V, the state (b) can be transferred to the predominant state even in the event of a fault in the voltage supply, and the brake booster is inoperable and the driver does not signal the braking request according to the state. In this case, the electromagnetic braking force distribution system is operated such that when the pressure increase is determined, the electromagnetic braking force distribution system increases the pressure rise. In such a case, however, the pressure rise is only possible if there is an error because braking must be preceded for this, in which case state b only exists if braking is not detected immediately.

The state (a) in which the brake booster is operable is preferably transmitted by a signal of 6V. This enables continuous monitoring of the signal, since state (a) predominates as the brake booster is operational in normal operation. This condition can be clearly distinguished from a cable break resulting in a signal of 0 V as a result, or an error in which a voltage of 12 V is applied.

In a faulty brake system, and in the driver's signaled additional braking request, state (c) is transmitted with a signal of 12V. In this signal, the electronic braking force distribution system can reduce the initial force for the driver, which is necessary for braking force enhancement.

According to an improvement of the invention, a separate voltage supply is assigned to the second communication link. Particularly preferably, the voltage supply is independent of the voltage supply for the brake booster and / or the voltage supply for the first communication link. The transfer of information from the brake booster to the electromagnetic braking force distribution system acts only on the voltage supply of the brake booster and / or the failure of the first communication link.

To this end, the components required for the second communication link in particular are supplied with a voltage from a separate voltage supply. This is the case where the second communication link comprises two separate communication channels for the transmission of information, in particular a brake request recognition means in the brake booster, and the second communication link corresponds to exactly one communication channel The drive unit is further supplied with a voltage by a separate voltage supply unit.

The above object is achieved by a method for operating a vehicle brake system, in which first information relating to a state of a brake booster and second information relating to a braking demand of a driver of a vehicle are transmitted separately from a first communication link between a brake booster and an electronic braking force distribution system, By means of a second communication link between the brake booster and the electronic braking force distribution system. In particular with respect to the method, the advantages already described in connection with the brake system are realized.

Within the scope of the method, preferably the brake system is operated in accordance with one of the embodiments described above.

According to an improvement of the present invention, the second communication link is used only in the case of failure of the first communication link. Preferably, the second communication link is activated only in the event of a failure of the first communication link. This means in particular a resource protection configuration, while at the same time the second communication link is made available when a second communication link is needed. When the first communication link is complete, the transmission of the information on the second communication link described above is not necessarily required. Nevertheless, it is also possible for a second communication link to be used simultaneously with the first communication link, in particular to implement redundancy.

Finally, the above problem is solved by providing a vehicle with a brake system according to one of the above-described embodiments. In this case, in particular the brake system and the advantages already described in connection with the method are implemented.

The vehicle preferably has a plurality of wheels, each of which is assigned an individual brake piston, in which case the electronic braking force distribution system is configured to distribute the braking pressure, particularly by wheel, to each brake piston of the wheels.

The vehicle is preferably formed as an automobile, particularly a passenger car, a lorry or a commercial vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in detail below with reference to the drawings.

1 is a schematic view of a first embodiment of a brake system.
2 is a schematic diagram of a second embodiment of a brake system.

1 is a schematic view of a first embodiment of a brake system 1 for a vehicle 3, in particular an automobile. The brake system 1 comprises a brake booster 5 and an electronic braking force distribution system 7 and the electronic braking force distribution system 7 is embodied or integrated in the central controller 9 of the vehicle 3 in particular. It is also possible that the central controller 9 is part of the electronic braking force distribution system 7.

The brake booster 5 and the electronic braking force distribution system 7 are interconnected for the exchange of information and / or data via a first communication link 11, particularly a CAN connection or a Flexray connection, only schematically shown here.

The brake system 1 has a second communication link 13 which is different from the first communication link 11 and which is particularly independent and the second communication link comprises first information relating to the state of the brake booster 5, 3) the second information on the driver's braking demand.

In this case, it is checked whether or not the microcomputer of the control device 15, in particular, the brake booster 5 is operable, and the braking demand of the driver is detected through the brake request recognizing means 17 allocated to the brake booster 5 do.

Here, the second communication link 13 comprises a first communication channel 19 for the transmission of the first information and a second communication channel 19 for the transmission of the second information, Channel. The communication channels 19 and 21 may each be implemented via a current interface, a voltage interface, or a pulse width modulation interface, i.e., a PWM interface. In this case, different current values and / or voltage values are assigned to different values of the first and / or second information. Particularly, since the voltage value of 0 V is assigned to the inoperative state of the control device 15 or the brake booster 5, this state can be maintained even when the control device 15 and the brake booster 5 are defective due to the voltage failure And can be securely transmitted through the communication channel 19. [ The second communication link 13 is preferably provided with a separate voltage supply, which supplies the voltage to the braking demand recognition means 17 in particular. This separate voltage supply is in particular independent of the voltage supply for the brake booster 5, in particular for the control device 15 and / or the first communication link 11.

The request signal 23 for braking force enhancement is generated by the central controller 9, preferably based on the information communicated via the second communication link 13 in particular.

Fig. 2 is a schematic view of a second embodiment of the brake system 1. Fig. Like elements are denoted by the same reference numerals, and therefore, the same reference numerals are used for the same elements. Here, the second communication link 13 has exactly one common communication channel 25, which is configured to transmit not only the first information but also the second information.

The second communication link 13 has a drive device 27 which is a combination of first information supplied from the control device 15 and particularly the second information supplied from the brake request recognition means 17 To drive the communication channel (25). From the information, the drive 27 generates a state or superposition for the common communication channel 25. [

The second communication link 13 may have a current interface, a voltage interface or a PWM interface. Also in this case, the current values and / or voltage values of the second communication link 13 are preferably assigned to different values or overlaps, which are different from the values of the first and second information.

Preferably, a separate voltage supply is assigned to the second communication link 13, which is in particular connected to the voltage booster for the brake booster 5, in particular for the control device 15 and / Lt; RTI ID = 0.0 > 11). ≪ / RTI > In this case, the separate voltage supply unit supplies voltage to the drive unit 27 as well as the braking demand recognition unit 17 preferably.

The common communication channel 25 is particularly preferably for a three-state transmission, i.e. a first state in which a brake booster is operable, here it is not important whether or not the driver's braking demand exists, 5) is inoperable and the driver does not signal the braking demand, and finally the third state in which the brake booster 5 is inoperable and the driver signals the braking demand. Particularly preferably, a different voltage value is assigned to the states, in particular a voltage value of 6V is assigned to the first state, a voltage value of 0V to the second state, and a voltage value of 12V to the third state.

Preferably, regardless of the specific embodiment of the brake system 1 according to Figs. 1 and 2, the second communication link 13 is activated only when the first communication link 11 fails. It is also possible that the second communication link 13 is used only when the first communication link 11 fails. Of course, it is also possible for the second communication link 13 and the first communication link 11 to be used simultaneously, in particular to provide redundancy.

Taken together, improved driver assistance in the event of failure of the brake booster 5 can be provided using the brake system 1, the method and the vehicle 3 proposed herein.

Claims (10)

A brake system (1) for a vehicle (3) having a brake booster (5) and an electronic braking force distribution system (7) interconnected via a first communication link (11)
A second communication link 13 different from the first communication link 11 is provided between the brake booster 5 and the electromagnetic braking force distribution system 7 and the second communication link 13 is connected to the brake booster 5, , And second information relating to a braking demand of the driver (3) of the vehicle (3). 2. A communication system according to claim 1, characterized in that the second communication link (13) comprises a first communication channel (19) for the transmission of the first information and a second communication Channel (21). ≪ / RTI > A vehicle brake system (1) according to claim 1 or 2, characterized in that the second communication link (13) has a communication channel (25) configured for transmission of the first information and the second information. 3. A communication system according to claim 1 or 2, characterized in that the second communication link (13) has a drive unit (27) configured to drive the communication channel (25) based on a combination of the first information and the second information (1). ≪ / RTI > 3. Vehicle brake system (1) according to claim 1 or 2, characterized in that the second communication link (13) has a current interface, a voltage interface or a PWM interface. 3. Vehicle brake system according to claim 1 or 2, characterized in that different values of the first information and / or the second information are assigned different current values and / or voltage values of the second communication link (13) (One). 3. Vehicle brake system (1) according to claim 1 or 2, characterized in that a separate voltage supply is assigned to the second communication link (13). A method of operating a brake system (1) for a vehicle (3)
The first information on the state of the brake booster 5 and the second information on the braking demand of the driver of the vehicle 3 are transmitted to the first communication link 11 between the brake booster 5 and the electromagnetic braking force distribution system 7 Separately, is transmitted via the second communication link (13) between the brake booster (5) and the electronic braking force distribution system (7). 9. A method as claimed in claim 8, characterized in that the second communication link (13) is used only in the event of a failure of the first communication link (11). A vehicle (3) having a brake system (1) according to claim 1 or 2.

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