Device for controlling brake lights of a motor vehicle with redundant signal lines, motor vehicle and method

Abstract

Device (2) for controlling brake lights (3) of a motor vehicle (1), comprising a brake pedal unit (6) for outputting a driver brake signal upon detection of an actuation of a brake pedal (4), a vehicle functional unit (7) for outputting a functional brake signal upon detection of a braking request from a driver assistance system (5) of the motor vehicle (1), and a brake light control unit (8) for controlling the brake lights (3) upon receipt of the driver brake signal and / or the functional brake signal, wherein the brake pedal unit (6) is connected to the brake light control unit (8) and the vehicle functional unit (7) is connected to the brake light control unit (8), characterized in that the vehicle functional unit (7) is connected to the brake light control unit (8) via a first signal line (18) and via a second signal line (24) separate from the first signal line (18).

Description

[0001] The present invention relates to a device for controlling brake lights of a motor vehicle, comprising a brake pedal unit for outputting a driver brake signal upon detecting an actuation of a brake pedal, a vehicle functional unit for outputting a functional brake signal upon detecting a braking request from a driver assistance system of the motor vehicle, and a brake light control unit for controlling the brake lights upon receiving the driver brake signal and / or the functional brake signal, wherein the brake pedal unit is connected to the brake light control unit and the vehicle functional unit is connected to the brake light control unit. The invention also relates to a motor vehicle having such a device. Finally, the present invention relates to a method for controlling brake lights of a motor vehicle.

[0002] The focus here is on the control of brake lights on a motor vehicle. During operation of the motor vehicle, the brake lights are activated when the driver presses the brake pedal. The actuation of the brake pedal can be detected using a brake pedal unit, which, for example, comprises a corresponding sensor or a switch. If the actuation of the brake pedal has been detected, a driver brake signal can then be output by the brake pedal unit and transmitted to a brake light control unit. The brake light control unit can then control the brake lights of the motor vehicle. It is known from the prior art that when the driver brakes, the driver brake signal is transmitted to the brake light control unit via a digital data bus and a direct hardware line.

[0003] Furthermore, driver assistance systems are used in motor vehicles that intervene in the longitudinal guidance of the vehicle or provide a braking request. Such driver assistance systems can be, for example, a distance control system, a system for performing emergency braking, or a system for parking a motor vehicle. If such a driver assistance system provides a braking request, a functional brake signal is usually provided by a corresponding vehicle functional unit and transmitted to the brake light control unit.

[0004] For this purpose, it is known from the prior art that this functional brake signal is transmitted to the brake light control unit via a digital data bus, for example via a CAN bus. A simple error, such as a disruption in the bus communication, leads to a failure of the brake light control. If an error is detected in the digital data bus, it can be provided, for example, that the brakes of the vehicle are not activated. In fully autonomous or piloted operation of the vehicle, however, such a procedure is not possible because in this case the driver does not control the vehicle themselves. This can lead to cases in which the vehicle is braked by the driver assistance system but the brake lights are not activated. This can pose a danger to following traffic.

[0005] DE 100 24 881 A1 describes a method for brake light control in motor vehicles. This involves generating signals using sensors that provide status data relating to the driving stability and / or braking status. Furthermore, the status data is recorded and evaluated, and a signal for controlling the brake lights is generated based on the evaluation results. Furthermore, it can be provided that status data from a release switch and / or a pressure sensor and / or a diaphragm travel sensor and / or an automatic braking process are used as a basis. If one sensor fails, the brake light control can be provided by the remaining sensors.

[0006] Furthermore, EP 1 050 444 B1 describes a device for brake light control, which has a control unit for controlling the vehicle brakes. Furthermore, a brake light switch is arranged in a region of a brake pedal and is connected to a control device for controlling at least one brake light. The control unit is coupled to the control device. The control device is actuated by the control unit in such a way that the brake lights can be activated under first, predetermined vehicle operating conditions and deactivated under second, predetermined vehicle operating conditions even without actuating the brake light switch.

[0007] Furthermore, DE 10 2004 024 514 A1 describes a signaling device for a motor vehicle, which comprises at least one signal generator, an engine control unit, and sensors for detecting a movement state of the motor vehicle. The behavior of the signal generator depends on the status of the engine control unit and can be influenced by the movement state detected by the sensors.

[0008] Furthermore, DE 39 30 775 A1 describes a method for controlling and monitoring the brake lights of a vehicle. The signal present at a brake light switch is additionally fed to a control and regulating unit in the vehicle, which receives a signal from at least one wheel speed sensor for evaluation. Furthermore, when the brake light switch is detected and / or when a braking operation is determined from the signal from the wheel speed sensor, a current for generating the brake lights is fed from the control and regulating unit to the brake lights.

[0009] The object of the present invention is to show a solution how the control of brake lights can be carried out more reliably when a driver assistance system of the motor vehicle requests braking.

[0010] This object is achieved according to the invention by a device, by a motor vehicle, and by a method having the features according to the respective independent claims. Advantageous developments of the present invention are the subject of the dependent claims.

[0011] A device according to the invention for controlling brake lights of a motor vehicle comprises a brake pedal unit for outputting a driver brake signal upon detecting an actuation of a brake pedal. The device further comprises a vehicle functional unit for outputting a functional brake signal upon detecting a braking request from a driver assistance system of the motor vehicle. The device further comprises a brake light control unit for controlling the brake lights upon receiving the driver brake signal and / or the functional brake signal, wherein the brake pedal unit is connected to the brake light control unit and the vehicle functional unit is connected to the brake light control unit. According to the invention, the vehicle functional unit is connected to the brake light control unit via a first signal line and via a second signal line separate from the first signal line.

[0012] The device can be used in a motor vehicle, for example in a passenger car, and serves to control the brake lights of the motor vehicle. The brake lights or stop lamps are part of the vehicle lighting, which is arranged at the rear of the motor vehicle and directed backwards. The device comprises the brake pedal unit, which outputs a driver braking signal if an actuation of the brake pedal is detected. The actuation of the brake pedal can be detected, for example, with the aid of a corresponding sensor or a switch on the brake pedal unit. The sensor on the brake pedal unit can detect the movement or travel of the brake pedal, the force acting on the brake pedal and / or the speed of the brake pedal. The brake pedal unit is connected to the brake light control unit for data transmission via at least one signal line.Thus, the driver's brake signal can be transmitted from the brake pedal unit to the brake light control unit. The brake light control unit can then, in turn, be used to control or activate the motor vehicle's brake lights. Furthermore, the device comprises a vehicle functional unit that is coupled to one or more driver assistance systems of the motor vehicle for data transmission. The driver assistance systems can be, for example, adaptive cruise control, a system for performing emergency braking, and / or a system for assisting the driver when parking.

[0013] This driver assistance system serves, in particular, to influence the longitudinal guidance of the motor vehicle. The driver assistance system can issue a braking request to decelerate the motor vehicle and transmit it to the vehicle functional unit. If the vehicle functional unit receives the braking request, it can output a functional braking signal. This functional braking signal can also be transmitted to the brake light control unit, and the brake light control unit can then control the motor vehicle's brake lights depending on the functional braking signal.

[0014] According to the invention, the vehicle functional unit is connected to the brake light control unit via the first signal line and via the second signal line, which is designed separately from the first signal line. This means that the functional brake signal can be transmitted from the vehicle functional unit to the brake light control unit via both the first signal line and the second signal line. Thus, in the event of automated braking or a braking request from the driver assistance system, the brake light can be controlled via the second independent signal line or channels. This means that, for example, in the event of a fault in the first signal line, the functional brake signal can be transmitted to the brake light control unit via the second signal line, thus reliably controlling the brake lights.In addition, the use of the second signal line typically requires fewer changes to the device's architecture. Furthermore, the device's components can remain unchanged. The redundant design of the signal lines for controlling the brake lights during automated deceleration thus enables safe operation, particularly during fully autonomous or piloted driving of the vehicle.

[0015] The brake pedal unit preferably includes an electronic brake booster. This electronic brake booster can be connected to the brake pedal and detect actuation of the brake pedal. For this purpose, the electronic brake booster can have a corresponding sensor or switch, as described above. Furthermore, the electronic brake booster can build up brake pressure in the brake lines. For this purpose, the electronic brake booster can have a corresponding actuator. The electronic brake booster can also serve to build up brake pressure when the functional brake signal is present or when braking is requested by the driver assistance system.

[0016] The first signal line and the second signal line preferably comprise at least one digital data bus and / or at least one analog data line. The first and / or the second signal line can be provided, for example, by a data bus or a communication bus. Such a digital data bus can be, for example, a CAN bus, a FlexRay connection, an Ethernet connection, or the like. It can also be provided that the first and / or the second signal line are provided by an analog data line or a hardware line. A signal in the form of an electrical voltage, which has, for example, a high level and a low level, can be transmitted via the analog data line. It can also be provided that the first signal line is designed as a digital data bus and the second signal line is designed as an analog data line.The additional hardware line allows the brake lights to be controlled more quickly than via a data bus line. This allows the functional brake signal to be reliably transmitted via the second signal line in the event of a fault in the first signal line or the digital data bus. Such a fault in the first signal line or the digital data bus can be caused, for example, by a low supply voltage.

[0017] In one embodiment, the first signal line and the second signal line each provide a direct connection between the vehicle functional unit and the brake light control unit. In other words, the vehicle functional unit is directly connected to the brake light control unit via both the first signal line and the second signal line. The brake lights are thus controlled redundantly when the driver assistance system issues a braking request. This ensures reliable control following the driver assistance system's braking request.

[0018] In a further embodiment, the first signal line provides a direct connection between the vehicle functional unit and the brake light control unit, and the second signal line is provided, at least in sections, by a further signal line that connects the brake pedal unit to the brake light control unit. To transmit the driver brake signal, the brake pedal unit can be connected to the brake light control unit via at least one further signal line. In particular, the brake pedal unit is connected to the brake light control unit via at least two further signal lines. At least one of these further signal lines can be used to additionally transmit the functional brake signal.

[0019] In addition, the functional brake signal can be transmitted directly from the vehicle functional unit to the brake light control unit via the first signal line. Thus, the existing architecture used to transmit the driver brake signal provides a second independent channel that can be used to transmit the functional brake signal.

[0020] Furthermore, it is advantageous if the vehicle functional unit is connected to the brake pedal unit for transmitting a request signal for a brake pressure, and if the vehicle functional unit additionally transmits the request signal to the brake pedal unit when outputting the functional brake signal. This embodiment is particularly suitable if the brake pedal unit comprises the electronic brake booster. The vehicle functional unit can be connected to the brake pedal unit, for example, via a corresponding data bus. The request signal can be transmitted via this data bus, as a result of which a brake pressure is built up by the brake pedal unit or the electronic brake booster. For example, the vehicle functional unit can output the request signal for the brake pressure simultaneously with the functional brake signal.In this way, the vehicle's brakes can be activated when the driver assistance system issues a braking request.

[0021] In a further embodiment, the brake pedal unit transmits a control signal via the at least one further signal line to the brake light control unit if the brake pedal unit detects the actuation of the pedal and / or receives the request signal. This control signal can correspond to or include the driver brake signal. The brake pedal unit can therefore transmit the control signal to the brake light control unit via the at least one further signal line if the driver depresses the brake pedal. In addition, the brake pedal unit can transmit the control signal to the brake light control unit if it receives the request signal from the vehicle functional unit. The vehicle functional unit outputs the request signal if it detects the braking request of the driver assistance system or outputs the functional brake signal. The functional brake signal is thus transmitted to the brake light control unit in the form of the control signal by means of the brake pedal unit.In this way, redundant control of the brake lights can be enabled.

[0022] In this case, it is preferably provided that the brake pedal unit transmits the control signal to the brake light control unit via at least two further signal lines, wherein the at least two further signal lines comprise at least one digital data bus and / or at least one analog data line. The brake pedal unit can also transmit the driver brake signal to the brake light control unit via two independent signal lines. Here, too, it can be provided that these two further signal lines are designed as a digital data bus and / or as an analog data line. In this case, it is particularly provided that the brake pedal unit transmits the driver brake signal to the brake light control unit via an analog data line after receiving the request signal from the vehicle functional unit.This means that both when the driver brakes and when the driver assistance system requests braking, the signals can be transmitted via two independent channels.

[0023] In a further embodiment, the device comprises an engine control unit, and the brake pedal unit additionally transmits the driver brake signal to the engine control unit. The engine control unit can be assigned to a drive motor of the motor vehicle. The engine control unit can also control the drive motor depending on whether the driver brake signal and / or the functional brake signal is output. The brake pedal unit can be connected to the engine control unit via at least one of the two further signal lines. For example, the brake pedal unit can be connected to the engine control unit via a data line. The driver brake signal can then be transmitted to the engine control unit via this data line. The engine control unit can then evaluate this driver brake signal accordingly and output a signal to the brake light control unit via a further data line.This allows the engine control unit to check whether the brake pedal has been depressed by the driver. This allows it to determine whether a braking request was made by the driver, the driver assistance system, or both.

[0024] In particular, it is provided that the engine control unit is connected to the brake pedal unit via the at least two additional signal lines, and the engine control unit is designed to check the transmission of the driver brake signal via the at least two additional signal lines. The engine control unit can receive the driver brake signal, for example, via a hardware line and / or via a data bus. Furthermore, the engine control unit can check whether the driver brake signal or the control signal was transmitted via the additional signal lines.

[0025] The brake light control unit is preferably designed to check the receipt of the driver brake signal and / or the receipt of the functional brake signal. Thus, the brake light control unit can be used to verify whether a braking request was made by the driver, the driver assistance system, or both. In both cases, it can be guaranteed that the brake lights are reliably controlled.

[0026] A motor vehicle according to the invention comprises a device according to the invention. The motor vehicle is designed, in particular, as a passenger car.

[0027] A method according to the invention is used to control brake lights of a motor vehicle. A brake pedal unit outputs a driver brake signal upon detecting actuation of a brake pedal. Furthermore, a vehicle functional unit outputs a functional brake signal upon detecting a braking request from a driver assistance system of the motor vehicle. Furthermore, a brake light control unit controls the brake lights upon receiving the driver brake signal and / or the functional brake signal, wherein the brake pedal unit is connected to the brake light control unit and the vehicle functional unit is connected to the brake light control unit. Furthermore, the functional signal is transmitted from the vehicle functional unit to the brake light control unit via a first signal line and via a second signal line separate from the first signal line.

[0028] The preferred embodiments presented with reference to the device according to the invention and their advantages apply accordingly to the motor vehicle according to the invention and to the method according to the invention.

[0029] Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention. Embodiments are therefore also to be regarded as encompassed and disclosed by the invention which are not explicitly shown and explained in the figures, but which emerge and can be produced by separate combinations of features from the explained embodiments. Embodiments and combinations of features are also to be regarded as disclosed which therefore do not have all the features of an originally formulated independent claim.

[0030] The invention will now be explained in more detail using preferred embodiments and with reference to the accompanying drawings. Fig. 1 a motor vehicle according to an embodiment of the present invention, which has a device for controlling brake lights, Fig. 2 shows a device for controlling brake lights according to the prior art in a schematic representation; and Fig. 3-6 Devices for controlling brake lights according to different embodiments of the invention in schematic representations.

[0031] In the figures, identical and functionally identical elements are provided with the same reference symbols.

[0032] Fig. 1 shows a motor vehicle 1 according to an embodiment of the present invention in a plan view. The motor vehicle 1 is embodied as a passenger car. The motor vehicle 1 comprises a device 2, which serves to control brake lights 3 of the motor vehicle 1. The device 2 is coupled, on the one hand, to a brake pedal 4. On the other hand, the device 2 is coupled to a driver assistance system 5 of the motor vehicle 1. A braking request can be provided by the driver assistance system 5. The driver assistance system 5 can be, for example, an adaptive cruise control system, an emergency braking assistant, or a parking system. Thus, the device 2 can control the brake lights 3 both when the driver actuates the brake pedal 4 and when the driver assistance system 5 issues a braking request.

[0033] Fig. 2 shows a device 2 for controlling the brake lights 3 according to the prior art in a schematic representation. The device 2 comprises a brake pedal unit 6, which is connected to the brake pedal 4. The brake pedal unit 6 can comprise a corresponding sensor with which the actuation of the brake pedal 4 can be detected. In addition, the brake pedal unit 6 preferably comprises an electronic brake booster with which a brake pressure can be built up in the brake lines. If the actuation of the brake pedal 4 has been detected, a driver brake signal can be output by the brake pedal unit 6. In addition, a signal can be output by the brake pedal unit 6 if a brake test switch has been actuated. The brake pedal unit 6 is connected to a brake light control unit 8 for data transmission.

[0034] The brake light control unit 8 can be used to control the brake lights 3 or brake lamps of the motor vehicle 1. In this case, the brake pedal unit 6 is connected to the brake light control unit 8 via a digital data bus 9 and an analog data line 10. The data bus 9 and the analog data line 10 are also connected to an engine control unit 11. In addition, the brake pedal unit 6 is connected to the engine control unit 11 via another analog data line 12. The signal when the brake test switch is actuated, for example, can be transmitted via this analog data line 12. The engine control unit 11 is in turn connected to the brake light control unit 8 via a digital data bus 13. The engine control unit 11 can be used to check the plausibility of the actuation of the brake pedal 4 or the driver's braking request.In addition, the engine control unit 11 can provide a safety function, for example, when using an electronic accelerator pedal. Overall, the brake pedal unit 6 is connected to the brake light control unit 8 via two channels. This is indicated by area 14.

[0035] The driver assistance system 5 in the present case comprises the units 15 and 16, which serve for the longitudinal guidance of the motor vehicle 1. In addition, a unit 17 is provided for coasting recuperation. The units 15, 16, 17 are connected to the vehicle functional unit 7. If a braking request is issued by the driver assistance system 5, a functional braking signal can be output by the vehicle functional unit 7. This functional braking signal is output in the present case via a first signal line 18, which comprises or is formed by a digital data bus 19. In addition, a further digital data bus 20 is provided, which transmits a signal when coasting recuperation is present to the brake light control unit 8. A further data bus 21 can be used to transmit a feedback signal from the brake light control unit 8 to the vehicle functional unit 7. In the present case, the transmission of the functional braking signal is via the first signal line 18 orthe data bus 19 is designed as a single-channel device. This is indicated by area 22.

[0036] Fig. Figure 3 shows a device 2 for controlling the brake lights 3 according to a first embodiment of the present invention. In the present embodiment, the unit 17 for detecting coasting recuperation is not shown. However, this can be implemented analogously to the device 2 according to Fig. 2. In the present case, the vehicle functional unit 7 is connected to the brake pedal unit 6 via a data bus 23. Thus, a request signal for providing a brake pressure can be transmitted from the vehicle functional unit 7 to the brake pedal unit 6 via the data bus 23. In particular, it is provided that this request signal is output by the vehicle functional unit 7 when the functional brake signal is output or a braking request is detected by the driver assistance system 5.

[0037] The brake pedal unit 6 is directly connected to the brake light control unit 8 via an analog data line 10'. The analog data line 12 is also present between the brake pedal unit 6 and the engine control unit 11. The brake pedal unit 6 can output the driver's brake signal. Furthermore, the brake pedal unit 6 or the electronic brake booster of the brake pedal unit 6 can provide braking pressure if the request signal is received. Thus, two separate analog data lines 10', 12 or hardware lines are present, which are compatible with the previous hardware wiring.

[0038] As soon as the brake pedal unit 6 detects the actuation of the brake pedal 4 and / or receives the request signal, it outputs a control signal to the brake light control unit 8 via the data line 10'. Thus, the functional brake signal can be transmitted separately from the first signal line 18 via the existing hardware line 10'. The data line 10' thus represents a second, independent signal line 24. Thus, even in the event of a failure of the first signal line 18 or the digital data bus 19, reliable control of the brake lights 3 is enabled via the second signal line 24. Thus, the transmission of the functional brake signal is also implemented via two channels. This is indicated, for example, by the area 22'.

[0039] The brake light control unit 8 is now designed to process the signal received from the engine control unit 11 via the data bus 13 and the functional brake signal received via the first signal line 18 using a logical OR operation. This allows plausibility to be determined as to whether a braking request is coming from the driver, from the driver assistance system 5, or both.

[0040] Fig. 4 shows a device 2 according to another embodiment in a schematic representation. It is provided that the brake pedal unit 6 transmits a control signal to the brake light control unit 8 via the data line 10 if it outputs the driver brake signal and / or receives the request signal from the vehicle functional unit 7. Thus, the control signal is output when the driver brakes or the driver assistance system 5 issues a braking request. The data bus 19, via which the functional brake signal is output, is connected to the engine control unit 11.

[0041] The engine control unit 11 receives the control signal via the data line 10. In addition, the engine control unit 11 receives the driver brake signal via the data bus 9 and the functional brake signal via the data bus 19. Thus, the engine control unit 11 can check whether the driver has actuated the brake pedal 4 and / or the braking request was provided by the driver assistance system 5. A signal can be output from the engine control unit 11 to the brake light control unit 8 via the data bus 13 if the data line 10 is set. The brake light control unit 8 corresponds to the brake light control unit according to the device 2 according to Fig. 4.

[0042] Fig. 5 shows a device 2 according to a further embodiment of the invention in a schematic representation. Here, the brake pedal unit 6 transmits the control signal both when the driver brake signal is present and when the request signal is received. The driver brake signal is only transmitted to the engine control unit 11 via the data bus 9 if the driver actuates the brake pedal 4. The control signal is only transmitted via the analog data line 12 if the request signal has been received or the driver assistance system 5 provides the braking request. A signal is then transmitted from the engine control unit 11 to the brake light control unit 8 via the data bus 13 if the control signal has been received via the data line 12.In this embodiment of the device 2, in the event of an undervoltage, it can be clearly distinguished whether the driver actuated the brake pedal 4 or whether the braking request was provided by the driver assistance system 5.

[0043] Fig. 6 shows a device 2 according to a further embodiment in a schematic representation. Here, the vehicle functional unit 7 is connected to the brake light control unit 8 via a further data bus 25. The further data bus 25 thus represents the second signal line 24. The brake pedal unit 6 and the engine control unit 11 correspond to those of the device according to Fig. 2. The brake light control unit 8 is modified so that it can receive the functional brake signal via the second data bus 25. In principle, it can also be provided that the vehicle functional unit 7 is connected to the brake light control unit 8 via two separate analog data lines.

Claims

[1] Device (2) for controlling brake lights (3) of a motor vehicle (1), comprising a brake pedal unit (6) for outputting a driver brake signal upon detecting an actuation of a brake pedal (4), a vehicle functional unit (7) for outputting a functional brake signal upon detecting a braking request from a driver assistance system (5) of the motor vehicle (1), and a brake light control unit (8) for controlling the brake lights (3) upon receiving the driver brake signal and / or the functional brake signal, wherein the brake pedal unit (6) is connected to the brake light control unit (8) and the vehicle functional unit (7) is connected to the brake light control unit (8), characterized by that the vehicle functional unit (7) is connected to the brake light control unit (8) via a first signal line (18) and via a second signal line (24) separate from the first signal line (18). [2] Device (2) according to claim 1, characterized bythat the brake pedal unit (6) comprises an electronic brake booster. [3] Device (2) according to claim 1 or 2, characterized by that the first signal line (18) and the second signal line (24) comprise at least one digital data bus (19, 25) and / or at least one analog data line (10, 10'). [4] Device (2) according to one of claims 1 to 3, characterized by that the first signal line (18) and the second signal line (24) each provide a direct connection between the vehicle functional unit (7) and the brake light control unit (8). [5] Device (2) according to one of claims 1 to 3, characterized bythat the first signal line (18) provides a direct connection between the vehicle functional unit (7) and the brake light control unit (8) and the second signal line (24) is provided at least in sections by at least one further signal line (10, 10') which connects the brake pedal unit (6) to the brake light control unit (8). [6] Device (2) according to claim 5, characterized by that the vehicle functional unit (7) is connected to the brake pedal unit (6) for transmitting a request signal for a brake pressure and the vehicle functional unit (7) additionally transmits the request signal to the brake pedal unit (6) when outputting the functional brake signal. [7] Device (2) according to claim 6, characterized bythat the brake pedal unit (6) transmits a control signal via the at least one further signal line (10, 10') to the brake light control unit (8) if the brake pedal unit (6) detects the actuation of the brake pedal (4) and / or receives the request signal. [8] Device (2) according to claim 7, characterized by that the brake pedal unit (6) transmits the control signal to the brake light control unit (8) via at least two further signal lines (10, 10'), wherein the at least two further signal lines (10, 10') comprise at least one digital data bus and / or at least one analog data line (10, 10'). [9] Device (2) according to claim 7 or 8, characterized by that the device (2) comprises an engine control unit (11) and the brake pedal unit (6) additionally transmits the control signal and / or the driver brake signal to the engine control unit (11). [10] Device (2) according to claim 9, characterized bythat the engine control unit (11) is connected to the brake pedal unit (6) via the at least two further signal lines (10, 10') and the engine control unit (11) is designed to check the transmission of the driver brake signal via the at least two further signal lines (10, 10'). [11] Device (2) according to one of the preceding claims, characterized by that the brake light control unit (8) is designed to check the reception of the driver brake signal and / or the reception of the functional brake signal. [12] Motor vehicle (1) with a device (2) according to one of the preceding claims. [13] Method for controlling brake lights (3) of a motor vehicle (1), in which a driver brake signal is output by means of a brake pedal unit (6) upon detection of an actuation of a brake pedal (4), a functional brake signal is output by means of a vehicle functional unit (7) upon detection of a braking request from a driver assistance system (5) of the motor vehicle (1), and the brake lights (3) are controlled by means of a brake light control unit (8) upon receipt of the driver brake signal and / or the functional brake signal, wherein the brake pedal unit (6) is connected to the brake light control unit (8) and the vehicle functional unit (7) is connected to the brake light control unit (8), characterized by that the functional brake signal is transmitted from the vehicle functional unit (7) to the brake light control unit (8) via a first signal line (18) and via a second signal line (24) separate from the first signal line (18).

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