Trailer and trailer brake controller and method and computer program product thereof

Abstract

The invention relates to a method for a trailer (16) having an electric drive (52) that can be coupled to a tractor (12), the method for controlling (120) the electric drive (52). The method comprises the following steps: receiving (109) a current accelerator pedal position (23) from the tractor (12) by means of a trailer brake control (42) of the trailer (16), generating (104, 106, 108, 112, 116) a control signal (62) for the electric drive (52) by means of the trailer brake control (42) as a function of the received current accelerator pedal position (23), and controlling (120) the electric drive (52) by means of the generated control signal (62). The invention also relates to a vehicle brake controller (32) for a tractor (12), a trailer brake controller (42) for a trailer (16), a vehicle (12) having a vehicle brake controller (32) or a trailer brake controller (42), and a computer program product for executing the method on a trailer brake controller (42).

Description

Technical Field

[0001] The invention relates to the control of an electric drive in a trailer. The trailer is towed by a tractor, such as a commercial vehicle. Such trailers towed by commercial vehicles, also referred to as trailers below, are in particular semitrailers and full trailers. Background Art

[0002] Commercial vehicles are known which, in addition to an internal combustion engine as the main drive source, also have at least one auxiliary electric drive. For example, electric drives are used in commercial vehicles in order to be able to operate the internal combustion engine in an energy-saving speed range or to provide additional thrust, for example when starting or driving uphill. In addition, the kinetic energy and potential energy of the vehicle can be recovered by the electric drive and stored as electrical energy in one or more energy accumulators.

[0003] It is also known that trailers for commercial vehicles can also be equipped with electric drives, so that, for example, additional driving force can be provided for the commercial vehicle through the trailer when driving uphill. In order to control the electric drive of the trailer, for example, a trailer having an electric drive is known from the document EP 2842 814 B1, which is coupled to a tractor with a hybrid or pure electric drive. The control of the electric drive of the trailer is achieved by coordinating the vehicle controller of the tractor and the additional energy management controller in the trailer. Other documents, such as the document EP 2 394 890 B1, describe the following solution, in which the electric drive of the trailer coupled to the tractor is controlled by a control signal, which is generated by measuring the coupling force between the trailer and the tractor. In terms of the control of the electric drive, for example, a fully automatically working trailer is known from the document US 9,694,712 B2, in which the control signal for the electric drive of the trailer is obtained based on sensors for determining acceleration and tilt angle.

[0004] All these known solutions have in common that they must be integrated into at least the existing system architecture of the trailer at great expense. According to the above examples, therefore, for example, additional controllers or complex additional sensor systems must be integrated into the trailer.

[0005] Furthermore, the solutions described have in common that they cannot be ideally integrated into the movement of the trailer, so that on the one hand energy recovery during braking is not achieved optimally and, for example, because the driving state recognition of the tractor on the one hand and the driving state recognition of the trailer by the sensor device of the electric drive on the other hand are independent of each other, this can lead to potential interference with safety and stability systems.

[0006] The prior art therefore discloses that the overall system consisting of the tractor and trailer must be fully overloaded in order to provide the trailer with sufficient information about the driving state of the trailer, for example by means of additional complex data transmission, or that complex additional sensor systems must be provided in the trailer when such additional integration effort in the tractor is to be avoided, which can lead to the above-mentioned problems, namely potential interference with the safety and stability systems. Summary of the invention

[0007] The object of the present invention is therefore to improve the integration of an electric drive into a trailer so that an electric drive with high efficiency can be included in as many driving situations as possible and can be easily integrated into existing control structures without the need for complex additional sensor devices or the need to provide additional control modules in the trailer.

[0008] According to the invention, a method according to claim 1 is proposed.

[0009] Therefore, a method for a trailer that can be coupled to a tractor is proposed. The method is used for a trailer with an electric drive, and the method is used to control the electric drive. Here, firstly, a current accelerator pedal position is received from the tractor by means of a trailer brake controller of the trailer. Furthermore, a control signal for the electric drive is generated by means of the trailer brake controller depending on the received current accelerator pedal position. The electric drive is then controlled by means of the current control signal.

[0010] According to the invention, a trailer brake controller of a trailer is used to generate a control signal for an electric drive of the trailer. It is particularly advantageous that a sufficient amount of information about the current state or driving state of the trailer is already provided to the trailer brake controller. For example, it is known from the prior art to provide the axle loads of the axles of the trailer, the acceleration in the longitudinal direction, the wheel speeds of at least two sensed wheels of the trailer and / or the absolute speed of the vehicle. Thus, by additionally receiving the current accelerator pedal position of the tractor towing the trailer, a positive acceleration request, i.e. a desired positive acceleration, can be derived in a supplementary and simple manner, and a signal for controlling the electric drive can be generated and outputted depending on the derived acceleration request. For integration, only the current accelerator pedal position of the tractor needs to be additionally informed to the trailer brake controller. Therefore, in existing systems, the current accelerator pedal position has not been transmitted to the trailer brake controller so that the main expenditure for integrating the control of the electric drive according to the invention lies in the additional transmission. When the accelerator pedal position is known, the existing trailer brake controller can supplement the function of generating the control signal in a simple manner.

[0011] Accordingly, a simple ready-to-go implementation of the actuation of the electric drive of the trailer vehicle is thus possible, wherein it is simultaneously taken into account that the actuation signals can be generated in a suitable manner by means of the trailer brake controller in order to ensure trouble-free safety and stability of the trailer vehicle.

[0012] Furthermore, according to a first embodiment, the charge state, also referred to as the state of charge (SoC), of at least one battery of the electric drive is detected by the trailer brake controller. The actuation signal is then generated by the trailer brake controller in dependence on the accelerator pedal position and the detected state of charge. Preferably, the measurement of the state of charge of one or more batteries of the electric drive is already provided in the electric drive. The result resulting from this measurement is preferably also provided by the known electric drive via a CAN interface and, according to the invention, can be retrieved in a simple manner via a CAN connection between the electric drive and the trailer brake controller and thus detected.

[0013] By taking the charge state of the battery into account, it is thus possible to take into account the extent to which the electric drive can contribute during acceleration, based on the available electrical energy reserve in the at least one battery. For example, if the battery is completely discharged, then even if the accelerator pedal position signals a strong acceleration request, no additional torque can be generated by the electric drive, so that according to this embodiment, the control signal for the electric drive is preferably also generated by a trailer brake controller that takes into account this discharge state of the battery, i.e., takes into account the control of the electric drive in such a way that no additional torque is provided.

[0014] According to a further embodiment, the current speed of the trailer is detected or provided by the trailer brake controller. The current speed is preferably provided to the trailer brake controller, which is connected to the vehicle brake controller of the tractor towing the trailer via a standardized data connection, in particular according to ISO 11992-2. The current speed is thus provided to the trailer brake controller for generating the actuation signal. Additionally or alternatively, the current speed is detected by a rotation speed sensor of the trailer brake controller in order to determine the rotation speed of the wheels of the trailer.

[0015] Furthermore, the current maximum torque value is determined in dependence on the current speed provided or detected by using a torque characteristic curve, which is preferably stored in the trailer brake controller or in the control unit of the electric drive and has a maximum torque that is dependent on the speed. Thus, a torque characteristic curve is provided, which assigns the maximum torque value of the electric drive to different speed values, for example in a range from 0 to 100 or up to 150 kilometers per hour. This maximum torque value is, for example, a preferred value at the current speed, which can be generated without the electric drive being outside of predetermined operating limits and without operating at an efficiency above a specified threshold. Thus, the maximum torque value can be determined for each current speed of the vehicle.

[0016] Here, the term torque characteristic curve is used to indicate a predefined relationship established between a maximum torque value and a speed value. A table or function that establishes a corresponding relationship may also be stored or provided instead of the torque characteristic curve.

[0017] Furthermore, the control signal is generated as a function of the current accelerator pedal position and the determined maximum torque. This is done, for example, by deriving a relative accelerator pedal position from the current accelerator pedal position. Preferably, the current accelerator pedal position already corresponds to a relative value of the accelerator pedal position, wherein it can also be provided that the current accelerator pedal position is indicated, for example, by an absolute value and therefore has to be converted into a relative accelerator pedal position. The relative accelerator pedal position then corresponds, for example, to a percentage value, and a control torque value is determined, which corresponds to a percentage value of the determined maximum torque value. Thus, a relative accelerator pedal position is derived from the current accelerator pedal position, for example a value of the accelerator pedal position between 0 percent and 100 percent, or, for example, when the current accelerator pedal position has already been received by the trailer brake controller as a relative value, for example in the range of 0 percent to 100 percent, this relative value is used to determine a control torque value, which corresponds to the percentage share of the accelerator pedal position relative to the currently determined maximum torque value.

[0018] Therefore, first the maximum torque value of the electric drive is detected in dependence on the speed, and the control torque is generated in dependence on the accelerator pedal position. This determined or acquired control torque is then used by the trailer brake controller to generate a control signal for the electric drive.

[0019] For this purpose, a control torque value or an adjusted control torque value derived from the control torque value, ie dependent on the control torque value, is output as a control signal to the electric drive. Thus, a control signal for the electric drive can be generated in a simple manner as a torque value.

[0020] According to a further embodiment, the charge state of at least one battery of the electric drive of the trailer is detected by means of a trailer brake controller. Detecting the charge state of the battery also includes receiving a signal indicating the charge state of the battery. Accordingly, for example, provision is already made in the electric drive to measure the voltage of the battery, which is dependent on the charge state, for example, and to transmit this voltage value or the charge state derived therefrom to the trailer brake controller, for example via a bus connection between the trailer brake controller and the electric drive. Thus, therefore, the detection includes receiving the charge state or receiving the voltage of the battery and deriving the charge state from the received voltage. According to this embodiment, the control torque value known in advance is then adjusted depending on the charge state and output as a control signal to the electric drive.

[0021] Accordingly, the control torque value is not output directly as a control signal as in the previous embodiment, but is adjusted in such a way that the control torque value takes into account the charge state of the battery of the electric drive. The adjusted control torque value is then output as a control signal to the electric drive of the trailer. It can be taken into account that, for example, in the case of a high charge level of the battery and a large amount of available energy generated thereby, a relatively high control torque value can be output as a control signal, so that the electric drive can make a relatively greater contribution to the overall desired acceleration of the combination consisting of the tractor and the trailer. For example, although the electric drive no longer operates within the ideal efficiency range at such a high torque value, it is meaningful to do so, for example, to discharge the battery so that there is enough free capacity to prepare for a braking process that may be coming later. On the other hand, it is possible that the control torque value can also be adjusted when the charge state of the battery is low, because there is no risk of a complete discharge of the battery due to the control of the electric drive and the generation of positive acceleration energy.

[0022] According to another embodiment, the control torque value is adjusted in such a way that the control torque value is increased when the state of charge is above a predetermined threshold value or threshold range. Here, the control torque value is increased, for example, by a predefined value or a predefined relative value of the control torque value. When the state of charge is below a predefined threshold value or threshold range, the control torque value is reduced. The reduction of the control torque value is also carried out, for example, by this or another predefined value or this or another predefined relative value of the control torque value. According to this embodiment, a threshold value or a threshold range is set accordingly, which is preferably predefined as follows so that it corresponds to a state of charge of at least one battery that substantially has the rated voltage of the electric drive or includes this state of charge. Preferably, since the battery is usually matched in terms of its voltage to the rated voltage of the motor to be powered by the electric drive when designing the electric drive, a threshold range of, for example, 40 to 60 percent of the total charge is suitable for forming the threshold range.

[0023] According to another embodiment, the generation of the control signal in dependence on the current accelerator pedal position received includes: the current expected accelerator pedal position of the tractor is known in dependence on the current state of the tractor vehicle and / or the trailer. Then, the received current accelerator pedal position is compared with the expected accelerator pedal position to obtain a comparison result. Then, the control torque value is additionally generated in dependence on the comparison result and output as a control signal for the electric drive. The current state of the trailer includes, for example, the vehicle mass, load distribution or load of the trailer known in the trailer brake controller. In addition, the state of the trailer preferably includes the vehicle speed and vehicle acceleration of the trailer, which are also known by the trailer brake controller. Therefore, in dependence on these known values ​​in the trailer brake controller, the expected accelerator pedal position can be compared with the currently received accelerator pedal position.

[0024] By comparison, i.e. depending on the comparison result, it is concluded that the vehicle is traveling uphill, for example, when the received current accelerator pedal position is higher than the expected current accelerator pedal position associated with the current speed and the vehicle is not accelerating or is even decelerating. For example, if the received accelerator pedal position is at or below the expected accelerator pedal position and the vehicle is accelerating or maintaining speed, it can be inferred from this that the vehicle is traveling downhill. If the received accelerator pedal position is higher than the expected accelerator pedal position and the vehicle is accelerating, it can be inferred from the driver's intention that the vehicle should accelerate positively. Correspondingly, if the received accelerator pedal position corresponds to the expected accelerator pedal position, it is assumed that the vehicle is traveling straight ahead at a constant speed. The comparison result thus shows the driving state of the combination.

[0025] Thus, from the comparison of the received accelerator pedal position with the expected accelerator pedal position, which reflects the driving state, it can be concluded that there is uphill driving, downhill driving, positive acceleration or straight driving with a constant speed, and that the electric drive is switched on, for example, when the efficiency of the electric drive is much higher than the efficiency of the internal combustion engine of the tractor. This is particularly the case in driving states such as vehicle acceleration and uphill driving. It should be noted that, except for special situations, the electric drive in the trailer is always more efficient than the internal combustion engine. The purpose here is to identify those situations in which the efficiency difference between the internal combustion engine and the electric drive is particularly large, from the known efficiency characteristics of the internal combustion engine in certain driving situations, i.e. it is considered particularly advantageous that the desired propulsion power should be partially taken over by the electric drive.

[0026] According to another embodiment, the current expected accelerator pedal position of the towing vehicle is determined in the trailer brake controller based on an accelerator pedal position characteristic curve, which indicates the expected accelerator pedal position depending on the current speed of the vehicle. For example, the accelerator pedal position characteristic curve is stored in the trailer brake controller. Therefore, the expected accelerator pedal position can be determined by the trailer brake controller in a simple and especially faster way. As before, a characteristic curve is also used here, wherein a table or function can also be provided, that is, the term "accelerator pedal position characteristic curve" can also be understood as an accelerator pedal position table, which matches the current speed value with the expected accelerator pedal position value, or can be understood as an accelerator pedal position function, which indicates the expected accelerator pedal position depending on the current speed of the vehicle.

[0027] According to a further embodiment, the accelerator pedal position characteristic curve is adjusted in the trailer control unit depending on further states of the trailer, in particular the current weight of the trailer. It is therefore taken into account that the mass of the tractor is essentially constant, while the trailer can have different total masses depending on the load. This has an effect on the required propulsion power, which increases relatively at a constant speed, for example. Therefore, if there is a relative change in the mass of the trailer, a relative change in the accelerator pedal position is also to be expected. This is taken into account by adapting the accelerator pedal position characteristic curve to the state of the trailer, in this case to the current weight or the current mass.

[0028] To explain the terminology, it is necessary to distinguish the current state of the trailer, which includes the current speed, mass, load distribution, etc., and the driving state includes uphill driving, downhill driving, positive acceleration intention, negative acceleration intention and normal straight driving.

[0029] According to another embodiment, the driving torque value is calculated according to the following formula:

[0030]

[0031] In this formula, A represents the accelerator pedal position and A* represents the expected accelerator pedal position. max (S1,v) represents the maximum torque of the electric drive as a function of the current speed of the vehicle. This then results in a control torque value M*, which also varies, for example, as a function of the state of charge.

[0032] Thus, when determining the control signal for the predetermined target torque value for the electric drive, it is possible to take into account in a simple manner, for example, the driving state, the possible torque of the electric drive and, if necessary, the charge state of the battery of the drive. In particular, it is found that the electric drive is not only used primarily for propulsion in energetically favorable situations, but also that the auxiliary power is directly related to the absolute level of the driver's desire to change the vehicle movement. In the case of uphill driving, in particular when the received accelerator pedal position is lower than the expected accelerator pedal position, the above formula leads to a negative torque. In this case, the actual controlled torque, i.e. the control signal, is 0.

[0033] According to another embodiment, the accelerator pedal position is received by the trailer brake controller via a CAN bus, i.e. a CAN bus according to ISO11992-2. Here, the accelerator pedal position is preferably transmitted using the message EBS 11. This message for receiving the accelerator pedal position preferably includes the relative value of the accelerator pedal position. According to ISO 11992-2, the data exchange between the vehicle brake controller of the tractor and the trailer brake controller of the trailer is anyway arranged via a CAN connection. Here, in particular, the message EBS 11 including the signal "Retarder Demand Value" has not been used so far. This message covers a value range from -125 percent to 125 percent. It is recommended to use the accelerator pedal position in percentage form directly as a signal in the positive value range of the message, i.e. only use the value range of 0 percent to 100 percent accordingly. For example, the negative value range can be used for the vehicle deceleration caused by the electric drive in the trailer.

[0034] In particular, this value of the accelerator pedal position is not directly output as the actual accelerator pedal position from the vehicle brake control of the tractor, but is additionally adjusted in conjunction with information known in the vehicle brake control of the tractor, for example about the steering angle and preferably with known geometric information of the vehicle combination, the current kink angle between the tractor and the trailer. For example, if the kink angle between the tractor and the trailer exceeds a value at which the trailer is coasting and thus unexpectedly folds over, a value of 0 percent is transmitted regardless of the actual accelerator pedal position. Thus, no additional data lines or data connections are required as the CAN communication via ISO 11992-2, which is provided in a standardized form via the ISO 7638 interface, i.e. the brake CAN bus, and the method is implemented only by additionally adjusting the vehicle brake control of the tractor, i.e. the vehicle brake control sends the accelerator pedal position value via the message EBS 11.

[0035] According to one embodiment, the actuation signal for the electric drive is also output from the trailer brake controller via the ISO 11992-2 CAN bus and is preferably received by the vehicle brake controller of the tractor. For example, the absolute value of the actuation signal is transmitted in message 23, and additionally or alternatively, the relative value of the actuation signal is transmitted in message 21. As a result, the vehicle brake controller of the tractor can take into account the additional thrust provided by the trailer. Therefore, the vehicle brake controller of the tractor can generate a request signal for the vehicle controller of the tractor based on the actuation signal.

[0036] The invention furthermore comprises a vehicle brake controller for a tractor vehicle for carrying out the method and a trailer brake controller for a trailer vehicle for carrying out the method according to any of the above-described embodiments. For example, the vehicle brake controller is configured to output the accelerator pedal position via an ISO 11992-2 CAN bus, wherein this is performed in particular as a message EBS 11. Furthermore, the vehicle brake controller is configured to receive a control signal from the trailer vehicle for controlling an electric drive of the trailer vehicle that can be coupled to the tractor vehicle. The control signal has, for example, a control torque value or an adjusted control torque value and is preferably received by the trailer brake controller via the ISO 11992-2 CAN bus, in particular as a message 21 and / or a message 23.

[0037] According to one embodiment of the vehicle brake controller, the vehicle brake controller is configured to output a request signal for the vehicle controller of the tractor vehicle as a function of the control signal that can be received by the trailer brake controller. The vehicle brake controller of the tractor vehicle can transmit a corresponding request to the drive of the tractor vehicle with the aid of this information about the current, preferably positive torque of the electric drive of the trailer vehicle in order to reduce its controlled torque equivalently. This is also referred to as acceleration blending. Alternatively, the drive torque of the tractor vehicle is not influenced by the torque in the controlled trailer vehicle, which is referred to as acceleration boost.

[0038] The trailer brake controller is configured to implement the method according to any one of the above-mentioned embodiments. In this case, the trailer is particularly configured to receive the accelerator pedal position from the tractor and generate a control signal, for example, including a control torque value or an adjusted control torque value, depending on the received accelerator pedal position, and output it to the electric drive.

[0039] Furthermore, the invention also comprises a vehicle, i.e. a tractor or trailer, having a vehicle brake controller or a trailer brake controller. Furthermore, part of the invention is a computer program product, i.e. software, which implements the method according to any of the above-described embodiments when the method is implemented on a trailer brake controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Further embodiments are obtained in conjunction with the embodiments explained in more detail in the accompanying drawings.

[0041] Figure 1 Showing the combination;

[0042] Figure 2 The efficiency characteristic curve is shown;

[0043] Figure 3 showing an accelerator pedal position characteristic curve; and

[0044] Figure 4 The steps of the method are shown. DETAILED DESCRIPTION

[0045] Figure 1 The combination 10 is shown, which comprises a tractor 12, for example a commercial vehicle, and which is connected to a trailer 16 via a drawbar 14. The trailer 16 can thus be towed by the tractor 12. The tractor 12 and the trailer 16 each comprise a plurality of axles 18, each of which has two wheels 20. Each wheel 20 is equipped with a friction brake 22 in order to brake the wheel 20 in the event of a braking request, i.e. a requested negative acceleration. At least one of the axles 18 of the tractor 12 is driven by an internal combustion engine or an electric drive, wherein for a better overview, the axles 18 are shown in FIG. Figure 1 Neither an internal combustion engine nor an electric drive is shown.

[0046] In order to drive the tractor 12, a request for a speed increase or a braking request is signaled by the operator of the tractor 12 changing the accelerator pedal position 23 of the accelerator pedal 24 and the brake pedal position 25 of the brake pedal 26. The accelerator pedal 24 is connected to a vehicle control unit 28 for forwarding the accelerator pedal position 23. The brake pedal 26 is connected to a vehicle brake control unit 32 for forwarding the brake pedal position 25. The vehicle control unit 28 forwards a control signal for controlling a drive (not shown) to a bus (not shown) connected to the vehicle control unit 28. The vehicle control unit 28 also transmits the accelerator pedal position 23 to the vehicle brake control unit 32 via a connection 34. The vehicle brake control unit 32 outputs the accelerator pedal position 23 in a message, in particular an EBS message 11, on a bus 30 standardized according to ISO 11992.

[0047] Furthermore, the friction brake 22 of the tractor vehicle 12 is connected to a vehicle brake control unit 32 so that, when a braking request is triggered via the brake pedal 26 , this braking request can be converted into a braking signal for the friction brake 22 of the tractor vehicle 12 .

[0048] In addition, the vehicle brake controller 32 of the tractor 12 generates a negative acceleration request signal for the trailer 16 in the case of a braking request, which is transmitted to the trailer brake controller 42 via the bus 30, and transmits a brake control pressure 36, which is also forwarded to the trailer 16 via the brake control line 38 as a negative acceleration request signal. The transmission of the negative acceleration request signal via the brake control line 38 can be regarded as a redundant transmission path. Therefore, in the normal state, the target value of the acceleration request signal via the bus 30 is used to drive the friction brake 22 of the trailer 16 via the trailer brake controller 42. In the case of a bus signal failure, the acceleration request signal is received via the brake control line 38. For this purpose, the brake control line 38 is connected to the first input 40 of the trailer brake controller 42. The sensor 44 of the trailer brake controller 42 converts the brake control pressure 36 transmitted via the brake control line 38 into an electrical signal 47 and sends it to the control unit 48 of the trailer brake controller 42. Depending on this signal 47, the friction brakes 22 of the two axles 18 of the trailer 16 shown here can be actuated. Therefore, depending on the brake control pressure 36 supplied to the trailer brake controller 42 via the brake control line 38 as an acceleration request signal, a signal, namely a brake actuation signal 50, is output to actuate the friction brakes 22.

[0049] In addition, the trailer 16 has an electric drive 52, which includes a rechargeable battery 54. In addition to the energy storage device 54, the electric drive also includes two converters 56, which use the energy from the battery 54 to supply energy to an electric motor 58 in order to generate a positive torque. The battery 54, the converter 56 and the electric motor 58 correspond to the component 59 of the electric drive 52. According to an alternative embodiment not shown here, only one electric motor 58 is provided for driving the two wheels 20 of the axle 18, which distributes its driving force to the wheels 20 via a differential transmission. In the case of only one electric motor 58, the electric drive 52 also includes only one converter 56.

[0050] The electric motor 58 can also be operated in generator mode or in generator operation, so that electrical energy is fed back into the battery 54 via the converter 56. Preferably, this generator operation is requested by the vehicle brake control 32 of the tractor 12 via the trailer brake control 42 when the driver wishes to brake. It can therefore be provided that the friction brake 22 is used as described above to implement the braking request only when the braking requested by the electric drive 52 is not sufficient to implement the braking request. In order to control the electric drive 52, that is, the converter 56, the electric drive 52 is connected to the trailer brake control 42 via a further bus 60.

[0051] The control of the converter 56 specifies, on the one hand, whether the electric motor 58 is operated in generator mode or in motor mode and which torque is to be used in this case. When the electric motor 58 is operated in motor mode, a positive torque is used, while when the electric motor 58 is operated in generator mode, a torque, i.e. a torque value, is referred to as a negative torque. In order to control the electric drive 52, i.e., in particular the converter 56, a control signal 62 is transmitted to the electric drive 52 by the trailer brake control 42 via a bus 60. In addition, the electric drive 52 transmits a charge state 64 to the trailer brake control 42, in order to be able to inform the trailer brake control 42, for example, or in particular, how much charge or charge quantity is currently available, for example, as an absolute value in ampere hours or as a relative value without units, which can be used for the capacity of the battery 54.

[0052] The trailer brake control unit 42 is also designed to generate an actuation signal 62 as a function of the charge state 64 and the received accelerator pedal position 23 and to output it via an interface 66 of the bus 30 , via which the charge state 64 is also received.

[0053] The trailer brake control unit 42 is accordingly connected to the bus 30 via a further input 68 in order to receive the accelerator pedal position 23. As described above, the bus 30 corresponds to a CAN bus and the input 68 corresponds to an interface for the CAN bus. It is therefore also possible that, in addition to receiving the accelerator pedal position 23 by the trailer brake control unit 42, an actuation signal 62 can also be transmitted to the vehicle brake control unit 32 of the tractor 12. This is done, for example, as a relative value 61 or an absolute value 63 of the actuation torque value of the actuation signal 62. Furthermore, the current speed 69 is also transmitted via the bus 30.

[0054] Figure 2 The efficiency characteristic curve 70 of one or more electric motors 58 of the electric drive 52 is shown. The efficiency characteristic curve 70 shows the efficiency range by means of contour lines 72, wherein the vehicle speed 76 is plotted on the horizontal axis 74 and the torque value 80 is plotted on the vertical axis 78. Based on the efficiency characteristic curve 70, a torque characteristic curve 82 is predetermined, which is determined in such a way that it indicates a maximum torque value 84 of the electric drive 52, i.e., its electric motor 58, in dependence on the speed 76, in which the electric drive 52 can advantageously be operated, for example, at rated power. The torque characteristic curve 82 thus associates the maximum torque value 84 at the current speed 86 of 80 km / h, which is exemplified here, with a maximum torque 88 of approximately 570 Nm. The torque characteristic curve 82 can be and is also considered below as an S1 characteristic curve. Therefore, the maximum torque value 84 corresponds to the torque value 88, which is located on the torque characteristic curve 82, i.e., the S1 characteristic curve, at the speed 86. Accordingly, according to the M max (S1,ν) determines the maximum torque value 84.

[0055] also, Figure 3 An accelerator pedal position characteristic curve 90 is shown, which assigns a percentage value of the accelerator pedal position shown on the vertical axis 94 to each speed value 76 shown on the horizontal axis 92. The accelerator pedal position characteristic curve 90 thus assigns an expected accelerator pedal position 96 to each speed 76 of the vehicle, which is expected in the case of constant straight travel on a flat route. The accelerator pedal position characteristic curve 90 is also stored in the trailer brake control unit 42, for example, and is adjusted by the trailer brake control unit 42 depending on the mass, which varies, for example, due to the load of the trailer 16. In this case, for example, a steeper course is shown by the dashed line 98 for relatively large masses.

[0056] Therefore, taking into account the efficiency characteristic curve 70, at least taking into account the torque characteristic curve 82 and the accelerator pedal position characteristic curve 90 stored in the trailer brake controller 42, the following is obtained: Figure 4 The steps of the method are shown.

[0057] Figure 4 The steps of an embodiment of the method are shown accordingly. Accordingly, step 100 shows that the current speed 69 is first determined or detected. Then in step 104, the maximum torque value 84 is determined in combination with the current speed 69 and the torque characteristic curve 82. In addition, in parallel in step 106, the expected accelerator pedal position 96 is determined in combination with the current speed 69 with the help of the accelerator pedal position characteristic curve 90. In advance in step 105, the accelerator pedal position characteristic curve 90 is determined depending on the state 107 of the trailer 16, such as the current mass of the trailer 16, or the saved accelerator pedal position characteristic curve 90 is adjusted. In step 108, the expected accelerator pedal position 96 is compared with the accelerator pedal position 23 received in step 109. For example, the comparison is performed according to the following formula: Here, A is the received accelerator pedal position 23, and A* is the expected accelerator pedal position 96. The comparison result 110 is then fed to step 112 in the same manner as the maximum torque value 84, and they are brought into relation with one another, for example by multiplication, so that a control torque value 114 is output from step 112. In a subsequent step 116, the charge state 64 of the battery 54 of the electric drive 52 is then used to adjust the control torque value 114. For this purpose, a threshold value 119 or a threshold value range 120 as well as a predefined value 121 and a predefined relative value 122 are fed. In step 118, the adjusted control torque value 115 is output as a control signal 62. For this purpose, the control signal 62 comprises, for example, a torque value which is fed to a converter 56 or converters 56 of the electric drive 52 and which is controlled in step 124. Furthermore, the activation signal 62 is output to the vehicle brake control unit 32 of the tractor 12 , which generates therefrom a request signal 126 for the vehicle control unit 28 in a step 125 and outputs it.

[0058] List of reference numerals (part of the specification)

[0059] 10 Combination

[0060] 12 Tractor

[0061] 14 Tow bar

[0062] 16 Trailer

[0063] 18 Axles

[0064] 20 wheels

[0065] 22 Friction brake

[0066] 23 Accelerator pedal position

[0067] 24 Accelerator pedal

[0068] 25 Brake pedal position

[0069] 26 Brake pedal

[0070] 28 Vehicle Controller

[0071] 30 Bus

[0072] 32 Vehicle brake controller

[0073] 34 Direct connection

[0074] 36 Brake control pressure

[0075] 38 Brake control circuit

[0076] 40 First input

[0077] 42 Trailer brake controller

[0078] 44 Sensors

[0079] 47 Electrical signal

[0080] 48 Control Department

[0081] 50 Brake control signal

[0082] 52 Electric drive

[0083] 54 Batteries

[0084] 56 Converter

[0085] 58 Electric Motor

[0086] 59 parts

[0087] 60 Additional Buses

[0088] 61 Relative value

[0089] 62 drive control signal

[0090] 63 Absolute value

[0091] 64 Charging status

[0092] 66 Interface

[0093] 68 Additional input

[0094] 69 Current speed

[0095] 70 Efficiency characteristic curve

[0096] 72 Contour Lines

[0097] 74 Horizontal axis

[0098] 76 Speed

[0099] 78 Vertical Axis

[0100] 80 Torque value

[0101] 82 Torque characteristic curve

[0102] 84 Maximum torque value

[0103] 86 Current speed

[0104] 88 Maximum torque

[0105] 90 Accelerator pedal position characteristic curve

[0106] 92 Horizontal axis

[0107] 94 Vertical Axis

[0108] 96 Expected accelerator pedal position

[0109] 98 dotted line

[0110] 100 Method Steps

[0111] 104-106 Method Steps

[0112] 107 Trailer status

[0113] 108, 109 Method Steps

[0114] 110 Comparison results

[0115] 112 Method Steps

[0116] 114 Drive torque value

[0117] 115 Adjusted drive torque value

[0118] 116-118 Method steps

[0119] 119 Threshold

[0120] 120 Threshold Range

[0121] 121 Predefined value

[0122] 122 Predefined relative values

[0123] 124, 125 Method steps

[0124] 126 Request signal

Claims

1. A method for a trailer (16) having an electric drive (52) which can be coupled to a tractor (12), the method for controlling the electric drive (52), the method comprising the following steps: - receiving (109) the current accelerator pedal position from the tractor (12) by means of a trailer brake controller (42) of the trailer (16), - generating a control signal (62) for the electric drive (52) by means of the trailer brake control unit (42) as a function of the received current accelerator pedal position, and - controlling the electric drive (52) using the generated control signal (62), The control signal (62) is output to the vehicle brake controller (32) of the tractor (12) via an ISO 11992-2 CAN bus (30) as a second message (21) and / or a first message (23), and a request signal (126) for a vehicle controller (28) is generated in the vehicle brake controller (32) as a function of the control signal (62), wherein the first message (23) is an absolute value (63) and the second message (21) is a relative value (61).

2. The method according to claim 1, wherein: Furthermore, the trailer brake controller (42) detects a charge state (64) of at least one battery (54) of the electric drive (52), and generates the actuation signal (62) using the trailer brake controller (42) as a function of the accelerator pedal position and the detected charge state (64).

3. The method according to claim 1 or 2, wherein: Generating the driving control signal (62) comprises: - detecting or providing (100) the current speed (69) of the trailer (16) in the trailer brake controller (42), - determining a maximum torque value (84) of the electric drive (52) by using a torque characteristic curve (82) having a speed-dependent maximum torque value (84) and a detected or provided current speed (69), and - determining a control torque value (114) as a function of the accelerator pedal position and the determined maximum torque value (84), - outputting (118) the determined control torque value (114) or a control torque value adjusted based on the determined control torque value (114) to the electric drive (52) as a control signal (62).

4. The method according to claim 3, wherein: The trailer brake controller (42) detects a charge state (64) of a battery (54) of the electric drive (52), adjusts (116) a control torque value (114) generated by the trailer brake controller (42) as a function of the detected charge state (64), and outputs the adjusted control torque value as a control signal (62) to the electric drive (52).

5. The method according to claim 4, wherein: The adjustment (116) of the control torque value (114) is carried out in the following manner, namely, - if the charge state (64) of at least one battery (54) is above a predefined threshold value (119) or a threshold range (120), increasing the control torque value (114), and - reducing the control torque value (114) when the state of charge (64) of the at least one battery (54) is below the predefined threshold value or another predefined threshold value (119) or threshold value range (120) for the state of charge (64).

6. The method according to claim 3, wherein: Generating a driving control signal (62) includes: - making known to the trailer vehicle (16) the current expected accelerator pedal position of the tractor vehicle (12), - comparing the received current accelerator pedal position with the expected accelerator pedal position (108) to obtain a comparison result (110), and - additionally generating the control torque value (114) as a function of the comparison result (110) for output as a control signal (62) for the electric drive (52).

7. The method according to claim 6, wherein: The knowledge of a currently expected accelerator pedal position of the tractor vehicle (12) is determined in dependence on an accelerator pedal position characteristic curve (90) which indicates the expected accelerator pedal position in dependence on a current speed (69) of the trailer vehicle (16).

8. The method according to claim 7, wherein: A gas pedal position characteristic curve (90) is adjusted (105) as a function of the current mass of the trailer (16).

9. The method according to claim 3, wherein: The driving torque value (114) is determined by the following formula: in M* is the acquired control torque value (114), A* is equivalent to the expected accelerator pedal position, A is equivalent to the received accelerator pedal position, and M max (S1,ν) corresponds to the maximum torque value (84) which depends on the current speed (69).

10. The method according to claim 1 or 2, wherein: The accelerator pedal position is received via the ISO 11992-2 CAN bus (30).

11. The method according to claim 5, wherein: The adjustment (116) of the control torque value (114) is carried out in the following manner, namely, When the charge state (64) of the at least one battery (54) is higher than a predefined threshold value (119) or a threshold range (120), the drive torque value (114) is increased by a predefined value (121) or a predefined relative value (122) of the drive torque value (114).

12. The method according to claim 5, wherein: The adjustment (116) of the control torque value (114) is carried out in the following manner, namely, When the charge state (64) of the at least one battery (54) is below the predefined threshold value or another predefined threshold value (119) or threshold range (120) of the charge state (64), the drive torque value (114) is reduced by a predefined value or another predefined value (121) or a predefined relative value or another predefined relative value (122) of the drive torque value (114).

13. The method according to claim 1 or 2, wherein: The accelerator pedal position is received via the message EBS11 .

14. A vehicle brake controller (32) for a tractor (12), wherein: The vehicle brake controller (32) is configured to implement a method according to any one of claims 1 to 13, wherein an accelerator pedal position is output via an ISO 11992-2 CAN bus (30) and a control signal (62) for controlling an electric drive (52) of a trailer (16) that can be coupled to the tractor (12) is received by a trailer brake controller (42) via the ISO 11992-2 CAN bus.

15. The vehicle brake controller (32) of claim 14, wherein: The vehicle brake control unit (32) is configured to output a request signal (126) for a vehicle control unit (28) of the tractor vehicle (12) as a function of the actuation signal (62).

16. The vehicle brake controller (32) of claim 14, wherein: The vehicle brake controller (32) is configured to output an accelerator pedal position via an ISO 11992-2 CAN bus (30) using a message EBS11 and to receive a control signal (62) for controlling an electric drive (52) of a trailer (16) that can be coupled to the tractor (12) from a trailer brake controller (42) via the ISO 11992-2 CAN bus using a second message (21) and / or a first message (23).

17. A trailer brake control unit (42) for a trailer (16), the trailer brake control unit being configured to carry out the method according to claim 1.

18. The trailer brake controller (42) of claim 17, wherein: An accelerator pedal position is received from the tractor (12), and a control signal (62) is generated depending on the received accelerator pedal position and output to the electric drive (52).

19. The trailer brake controller (42) of claim 17, wherein: A control signal (62) having a control torque value (114) or an adjusted control torque value is generated as a function of the received accelerator pedal position and output to the electric drive (52).

20. Vehicle having a vehicle brake controller (32) according to any one of claims 14 to 16 or a trailer brake controller (42) according to claim 17.

21. Computer program product, which is implemented on a trailer brake control unit (42) according to any one of claims 17 to 19, for implementing the method according to any one of claims 1 to 13.

Images