Electric drive device for a vehicle and method for operating an electric drive device for a vehicle

Abstract

The invention provides an electric drive device (10) for a vehicle (F), comprising a first electric drive arrangement (E1), a second electric drive arrangement (E2) and a control device (SE), which is connected to the first electric drive arrangement (E1) and the second electric drive arrangement (E2) and is set up to acquire a first operating temperature (T1) of the first electric drive arrangement (E1) and a second operating temperature (T2) of the second electric drive arrangement (E2) and to control the generation of a first torque (M1) on the first electric drive arrangement (E1) and / or a second torque (M2) on the second electric drive arrangement (E2) depending on the driving situation of the vehicle and / or depending on the first operating temperature (T1) and / or the second operating temperature (T2).

Description

Technical Field

[0001] The present invention relates to an electric drive device for a vehicle and a method for operating the electric drive device for a vehicle. Background Technology

[0002] Traditional electric vehicles mostly consist of only one electric drive unit per axle and include a differential for distributing torque, which can also be used to balance different wheel speeds when cornering.

[0003] Furthermore, for electric vehicles with two driven axles, the ratio of the applied torque between the front and rear axles can be changed.

[0004] It should be noted that the strategies used for torque distribution are typically based on a response to the already limited torque limits of the drive unit.

[0005] EP 2428704 A1 describes an oil supply device with a regulator. The regulator can be used to set the drive torque value and to regulate the electric motor so that the electric motor outputs a drive torque corresponding to the oil temperature. Summary of the Invention

[0006] The present invention provides an electric drive device for a vehicle according to claim 1 and a method for operating the electric drive device for a vehicle according to claim 7.

[0007] The preferred improvement is the subject of the dependent claims.

[0008] Advantages of the present invention

[0009] The present invention is based on the concept of describing an electric drive device for a vehicle and a method for operating the electric drive device for a vehicle, wherein torque distribution can be generated between a first drive unit and a second drive unit. This reduces or even avoids excessive heating of one of the drive units. Furthermore, preventative adjustments to the torque distribution can be implemented, representing a response to increased temperature in one or both drive units.

[0010] Therefore, the change in torque can represent a degree of freedom, which can typically be used to improve driving performance (acceleration, cornering), where the torque distribution can be dynamically matched to driving conditions. The minimum and maximum values ​​of the torque distribution, or the sum of the two torques, can be guided by the current state (temperature, voltage level) of the driven shaft and battery.

[0011] In the event that one of the two drive units reaches a critical temperature, it is possible that the relevant drive unit limits the maximum available torque. The unattainable portion of that torque can then be applied by the other shaft. If such limitations are implemented on both shafts, the total torque can be reduced. If redistribution is not possible at the extreme temperature due to current driving conditions, the total torque is also limited.

[0012] According to the present invention, the electric drive device for a vehicle comprises: a first electric drive unit capable of being mounted on the front axle of the vehicle; a second electric drive unit capable of being mounted on the rear axle of the vehicle; and a control unit connected to the first and second electric drive units and configured to: acquire a first operating temperature of the first electric drive unit and a second operating temperature of the second electric drive unit and control the generation of a first torque on the first electric drive unit and / or a second torque on the second electric drive unit according to the driving conditions of the vehicle and / or according to the first operating temperature and / or according to the second operating temperature, wherein the torque to which the first torque or the second torque belongs, if its operating temperature exceeds a predetermined value, can be reduced, and if the operating temperature to which the corresponding additional torque belongs, if its operating temperature is less than the predetermined value, then the corresponding additional torque can be increased.

[0013] The control device can be a control device that can also control a motor (on one or both drive units), wherein the motor can be connected to the vehicle's onboard electrical network.

[0014] The driving conditions can be specific power requirements (e.g., different or the same) on one of the axles or other pre-defined or required conditions, such as starting on a slope, while turning, under different loads, etc.

[0015] The predetermined value can correspond to a predetermined limit value of temperature on the corresponding drive device, wherein it can be considered that the operation of the drive device below this limit value can protect the drive device and the drive device can then generate maximum power and torque.

[0016] Therefore, the torque distribution can be adjusted even when approaching the operating limit temperature of the corresponding drive unit. This early response reduces further temperature rise in the heated drive unit.

[0017] The drive unit can be used and present in electric vehicles, (plug-in) hybrid vehicles, fuel cell vehicles, small electric motorcycles, electric bicycles with two independent electric drive units, or other vehicles. In such vehicles, a defined temperature ratio between the drive units or compensation for temperature imbalances can be achieved by adjusting the torque distribution.

[0018] By improving the torque distribution, greater availability of peak power for the two drive units can be achieved, greater availability of the maximum adjustable range of the torque distribution can be achieved, and support of the cooling system in regulating the temperature of the drive units can be achieved.

[0019] According to the invention, it is advantageous to identify a colder drive unit and subject it to a larger load than a hotter drive unit, wherein the colder drive unit can then bear a reduced torque on the hotter drive unit. Therefore, thermal equilibrium can be achieved between the drive units, or at least close to it, thereby delaying or even preventing a reduction in torque limits. This thermal redistribution can be implemented in non-hazardous driving conditions, such as straight-line driving. In driving conditions requiring other non-thermal distribution, the distribution can be shifted to a distribution of driving power, and this distribution is thus prioritized, allowing for a larger adjustment range for torque and a larger total torque, since the temperature of the drive units can be balanced at least partially beforehand.

[0020] According to a preferred embodiment of the electric drive device, the predetermined values ​​include a first limit value for the first operating temperature and a second limit value for the second operating temperature.

[0021] The drive unit can be designed and constructed differently and therefore have different temperature limits, from which the power and / or applicable torque of the drive unit may be adversely affected.

[0022] Furthermore, it is possible to have more than two electric drive units, and then to obtain and consider additional operating temperatures for these additional drive units, and to perform torque distribution under these drive units. It is also possible to compare any number of operating temperatures of the drive units. Here, this corresponding operating temperature should be matched with the corresponding component (drive unit). For example, front / rear rotor temperature, front / rear oil temperature, front / rear stator temperature, front / rear semiconductor temperature. For example, a vehicle with three motors can exist and be considered, with one motor in the front axle and two motors in the rear axle. Therefore, more than two drive units and motors can exist, for example, two motors on each axle of a vehicle.

[0023] According to a preferred embodiment of the electric drive device, the electric drive device includes: a first temperature sensor device for the first electric drive device, which is capable of detecting the first operating temperature and transmitting it to the control device; and a second temperature sensor device for the second electric drive device, which is capable of detecting the second operating temperature and transmitting it to the control device.

[0024] According to a preferred embodiment of the electric drive device, the electric drive device includes an adjustment device that can adjust the torque distribution between the first electric drive device and the second electric drive device.

[0025] The regulating device can adjust the torque generation on the corresponding drive device according to the current temperature on the drive device by controlling the motor on the drive device accordingly.

[0026] According to a preferred embodiment of the electric drive device, the control device is configured to: generate a first difference between the maximum limiting temperature of the first electric drive device and the current temperature and / or a second difference between the maximum limiting temperature of the second electric drive device and the current temperature, and infer from these differences a reserve of torque to be generated in the respective drive device. In this sense, other temperatures and their differences for other components can also be generated.

[0027] Regarding the maximum limiting temperature, this can involve a predetermined parameter, advantageously the parameter to which the drive device begins to reduce the maximum permissible torque. Then, the maximum permissible torque for this drive device can be reduced proportionally to any further increase in temperature. The limiting temperature does not necessarily correspond to the maximum permissible temperature of the corresponding component. More precisely, this limiting temperature can describe a temperature value from which component protection functions (e.g., torque distribution) can be activated and the maximum torque (peak torque) can be limited.

[0028] The maximum limiting temperature can correspond to a predetermined value for the operating temperature on the corresponding drive unit. The reserve can represent the untapped potential of the drive unit, for example, how much torque can still be delivered on the drive unit before reaching the maximum (predetermined) limiting temperature, given that there is still an acceptable remaining increase in operating temperature.

[0029] According to a preferred embodiment of the electric drive device, the control device is configured to influence the first operating temperature and / or the second operating temperature through a possible torque distribution, so as to keep the first operating temperature and / or the second operating temperature below the corresponding limit values.

[0030] The torque distribution can be controlled by corresponding manipulation of the motor and / or transmission mechanism on the corresponding drive unit.

[0031] According to the present invention, in the method for operating an electric drive device for a vehicle: providing the electric drive device according to the present invention; obtaining a first operating temperature of the first electric drive device and a second operating temperature of the second electric drive device; controlling the generation of a first torque on the first electric drive device and / or a second torque on the second electric drive device via the control device according to the driving conditions of the vehicle and / or according to the first operating temperature and / or the second operating temperature, wherein the torque to which the first torque or the second torque belongs exceeds a predetermined value is reduced, and if the operating temperature to which the corresponding additional torque belongs is less than the predetermined value, then the corresponding additional torque is increased.

[0032] The increase in torque on the cooler drive unit can advantageously continue until the drive unit reaches its limit temperature, at which point the vehicle's total torque can be maintained. The total torque can only be reduced when the operating temperatures of both drive units are at or above their limit values. These limit values ​​can be less than a critical temperature from which the drive unit can provide very little torque or no torque at all. Therefore, temperature adjustments on the respective drive units can advantageously be made preventatively before the operating temperature of that drive unit approaches the critical temperature.

[0033] According to a preferred embodiment of the method for operating an electric drive device, the current temperature and the maximum limit temperature and / or the maximum achievable torque and the minimum achievable torque are obtained for the first electric drive device and / or for the second electric drive device.

[0034] According to a preferred embodiment of the method for operating an electric drive device, a first difference between the maximum limit temperature and the current temperature for the first electric drive device and / or a second difference between the maximum limit temperature and the current temperature for the second electric drive device are formed, and a reserve of torque to be generated for the respective drive device is obtained therefrom.

[0035] According to a preferred embodiment of the method for operating an electric drive device, an adjustment deviation is obtained by obtaining, for the respective drive device, the adjustment deviation from the difference between a predetermined temperature difference between the two drive devices relative to each other and a corresponding difference of the drive device, wherein the predetermined temperature difference represents a weighted average for the utilization of the reserve, wherein the adjustment deviation is converted into a torque distribution between the drive devices and / or the adjustment deviation is set by an adjustment device.

[0036] The predetermined temperature difference can correspond to the desired load difference of the drive device, but it can also be zero.

[0037] The adjustment deviation can represent an auxiliary parameter used to determine the still possible reserves of temperature and torque that can be generated on the respective drive unit or on both drive units.

[0038] According to a preferred embodiment of the method for operating an electric drive device, the regulating device is pre-defined with a characteristic curve for distributing torque on the drive device.

[0039] The characteristic curves allow for better prediction of the operation of the regulating device.

[0040] According to a preferred embodiment of the method for operating an electrically driven device, the first operating temperature and / or the second operating temperature are affected by the resulting torque distribution in order to keep the first operating temperature and / or the second operating temperature below their respective limit values.

[0041] Furthermore, the method is also distinguished by the fact that it incorporates the features and advantages mentioned in the electric drive device, and vice versa.

[0042] Other features and advantages of embodiments of the present invention will become apparent from the following description with reference to the accompanying drawings. Attached Figure Description

[0043] The invention will now be explained in detail with the aid of embodiments illustrated in the accompanying drawings.

[0044] in:

[0045] Figure 1A schematic diagram of a vehicle having an electric drive device according to an embodiment of the present invention is shown;

[0046] Figure 2 A block diagram is shown for obtaining parameters in an electric drive device for operating a vehicle according to an embodiment of the present invention;

[0047] Figure 3 Characteristic curves of a regulating device for an electric drive device according to an embodiment of the present invention are shown; and

[0048] Figure 4 A block diagram illustrating the method steps of an electric drive device for operating a vehicle according to an embodiment of the present invention is shown.

[0049] In the accompanying drawings, the same reference numerals denote the same or functionally identical elements. Detailed Implementation

[0050] Figure 1 A schematic diagram of a vehicle having an electric drive device according to an embodiment of the present invention is shown.

[0051] The electric drive device 10 for vehicle F includes: a first electric drive unit E1, which can be mounted on the front axle of the vehicle; a second electric drive unit E2, which can be mounted on the rear axle of vehicle F; and a control unit SE, which is connected to the first electric drive unit E1 and the second electric drive unit E2 and is configured to: acquire a first operating temperature of the first electric drive unit E1 and a second operating temperature of the second electric drive unit E2 and control the generation of a first torque on the first electric drive unit E1 and / or a second torque on the second electric drive unit E2 according to the driving conditions of the vehicle and / or according to the first operating temperature and / or the second operating temperature, wherein the torque to which the first torque or the second torque belongs has an operating temperature exceeding a predetermined value can be reduced, and if the operating temperature to which the corresponding other torque belongs is less than the predetermined value, then the corresponding other torque can be increased.

[0052] The electric drive device 10 may include: a first temperature sensor device TS1 for the first electric drive device E1, which can detect a first operating temperature and transmit it to the control device SE; and a second temperature sensor device TS2 for the second electric drive device E2, which can detect a second operating temperature and transmit it to the control device SE.

[0053] The first drive device E1 can be formed as an electric shaft and includes the first temperature sensor device TS1. The second drive device E2 can be formed as an electric shaft and includes the second temperature sensor device TS2.

[0054] The electric drive device 10 may include an adjustment device RE, which can adjust the torque distribution between the first electric drive device E1 and the second electric drive device E2.

[0055] Figure 2 A block diagram is shown for obtaining parameters in a method for an electric drive device for operating a vehicle according to an embodiment of the present invention.

[0056] Figure 2 A general strategy for distributing torque under a drive unit is shown. Here, a basic strategy (signal facFDef) for torque distribution can be selected and predetermined. This basic distribution is formed, for example, by optimization of traction or consumption. Here, the corresponding adjustment parameters can be converged in the regulator DD or predetermined there. However, the regulator DD can also be omitted here.

[0057] A correction value can now be added to this basic distribution facFDef, which is responsible for balancing (regulating) the temperature of the drive unit (facFTemp). If no active compensation is needed, this signal is zero. The resulting signal facFTot is then a preset value for torque distribution, which also serves as a reference and can be achieved by the system within the current torque limits. This means that if the desired total torque (tqReqTotLim) cannot be achieved using the distribution factor facFTot, the distribution factor can be readjusted in block LimTot if necessary. This is important when the driver themselves want to invoke maximum torque due to hot axles during active redistribution.

[0058] Then, the target torque (tqDesFront) for the front drive unit and the target torque (tqDesRear) for the rear drive unit are calculated using the output signal of LimTot and the total torque. The block LimTqReq describes the limitation on the total torque based on the maximum torque fed back from the front and rear drive units.

[0059] It is important to understand that all signals with a "fac" term always describe an allocation value between 0 and 1. A value of 0 means that the desired torque is achieved entirely through the rear axle, and a value of 1 means that the desired torque is achieved entirely through the front axle. The core of this invention lies in the calculation of facFTemp and its additive embedding into an operating strategy or into a known operating strategy that can be used together.

[0060] The driving device can be, for example, in Figure 1 The drive device is as shown. Temperature sensor devices (not shown) can be present on the first drive unit E1 and the second drive unit E2, respectively. The first drive unit E1 and the second drive unit E2 can provide measurement signals to a control device, which can then acquire the temperature ratio and torque ratio of the drive unit. A first operating temperature T1 (commonly referred to as Tact) can be acquired on the first drive unit E1 and a second operating temperature T2 (commonly referred to as Tact) can be acquired on the second drive unit; the first and second operating temperatures represent the current temperature during operation. Similarly, the first torque and the second torque can be acquired. For each drive unit, a predetermined limit value Tmax can be known and transmitted to the control device, wherein the predetermined value can include a first limit value Tmax for the first operating temperature and a second limit value Tmax for the second operating temperature. Limit values ​​for the torque of the drive unit can also be predetermined or known regarding the temperature limits, and these current torque limits tqMin and tqMax can then be transmitted to the control device. Figure 2 The symbolic representation is shown in limTot as a routine assessment procedure. Figure 2 In this diagram, the torque limits for the two drive units are given the same reference numerals, but the torque limits can differ from each other when the operating temperatures on the drive units are different and / or the sizes of the drive units are different. The temperature information can be sent either as the maximum (limit value) and / or the current operating temperature or as the resulting difference (dT1, dT2).

[0061] The control device can be configured to: form a first difference dT1 between the maximum limit temperature Tmax of the first electric drive device E1 and the current temperature Tact and / or a second difference dT2 between the maximum limit temperature Tmax of the second electric drive device E2 and the current temperature, and infer from these differences a reserve of torque to be generated in the respective drive device.

[0062] If the drive unit detects multiple temperatures, then those temperatures that represent critical temperatures in terms of torque limitation can be used.

[0063] By comparing the thermal reserves dT1 and dT2, information is obtained about which drive unit currently has a smaller temperature reserve. The current thermal trim signal can then be further used for adjustment to set the desired trim. This trim can reflect different torque distributions on the drive unit.

[0064] Next, the adjustment deviation e can be obtained, which for the respective drive units (E1, E2) can be obtained from the difference between the predetermined temperature difference dTdes between the two drive units relative to each other and the corresponding difference (dT1, dT2) of the drive units, wherein the predetermined temperature difference dTdes can represent the weighting of the utilization of reserves, and wherein the adjustment deviation e can be converted into the torque distribution between the drive units (E1, E2) and / or can be set by the adjustment device.

[0065] The adjustment deviation e can be formed by the difference between a pre-defined target trim (dTdes) and the current trim (the difference between dT1 and dT2). The target trim can pre-defined weighting of the utilization of heat reserves between the first and second drive units, such as between the front and rear drive units. For negative values ​​of dTdes, it can be specified that the heat reserves of the first drive unit, such as the front drive unit, should be weighted more strongly (e.g., greater power / duration on the front drive unit for regeneration). Positive values ​​of dTdes can represent a higher weighting of the second drive unit, such as the rear drive unit (e.g., greater power / duration on the rear drive unit for acceleration).

[0066] The adjustment deviation can be generated by a regulator, such as a P regulator with a gain K, and converted into a correction (difference, and deviation from uniform distribution) facFTemp caused by torque distribution. The gain (K) can be predetermined as a constant value, or the input-output characteristics of the regulator can be predetermined as a characteristic curve, for example, according to... Figure 3 By predefining the characteristic curve, nonlinear characteristics can be achieved, such that, for example, a range is predefined within which torque distribution should not be changed or should be changed only slightly for small adjustment deviations.

[0067] The output signal facFTemp then represents a change in torque distribution to influence the temperature ratio. This temperature ratio can be superimposed, for example, based on energy efficiency or driving dynamics, with a non-temperature-specific distribution to form the final distribution value facFtot. This distribution value can be interpreted such that for a value of 0.5, the two drive units provide the same torque. If its value equals 1, the total torque is provided solely by the front drive unit, and when the value is 0, the total torque is provided solely by the rear drive unit. Furthermore, the distribution value facFTot and the total torque tqReqTotLim (together for both drive units) can be limited based on the current torque constraints, and can be converted into target torque tqDesFront for the front drive unit and target torque tqDesRear for the rear drive unit. Here, for example, standard processing methods can be used.

[0068] The box 'x' describes the multiplication. This, along with the box '1', is used to convert the total torque into the torque used for the drive mechanism. tqDesFront = facFtot * tqReqTotLim or tqDesRear = (1 - facFtot) * tqReqTotLim.

[0069] In this context, tqReqTot(total requested torque) represents the torque requested by the driver, and tqReqTotLim(total limited requested torque) represents the driver's desired torque limited to the limits of the axle.

[0070] Figure 3 Characteristic curves for a regulating device for an electrically driven device according to an embodiment of the present invention are shown.

[0071] As in the method according to the invention and in combination Figure 2 As described, an adjustment deviation e (in Kelvin) can be obtained, which can be converted into torque distribution between drive units and / or can be set by an adjustment device. Here, the adjustment device can be pre-defined with a characteristic curve KL for distributing torque on the drive units.

[0072] The Y-axis depicts the variation in torque distribution. This torque distribution is a value between 0 and 1 and describes the ratio of front axle torque to total torque. A Y-value of 0.1 in the graph means that the front axle (relative to the total torque) carries 10% more torque. Correspondingly, a value of -0.2 means that the rear axle carries 20% more torque.

[0073] The regulating device can be, for example, a P regulator with gain and can be converted into torque distribution adjustment. The input-output characteristics of the regulator can be predetermined as a characteristic curve KL. Predetermining the characteristic curve enables nonlinear characteristics so that, for example, a range should be predetermined within which small regulation deviations should not cause changes in torque distribution.

[0074] Figure 4 A block diagram illustrating the method steps of an electric drive device for operating a vehicle according to an embodiment of the present invention is shown.

[0075] In the method for operating an electric drive device for a vehicle: S1 providing the electric drive device according to the invention; S2 obtaining a first operating temperature of the first electric drive device and a second operating temperature of the second electric drive device; and controlling, via the control device, S3 the generation of a first torque on the first electric drive device and / or a second torque on the second electric drive device according to the vehicle's driving conditions and / or according to the first operating temperature and / or the second operating temperature, wherein the torque to which the first torque or the second torque belongs exceeds a predetermined value is reduced, and if the operating temperature to which the corresponding other torque belongs is less than the predetermined value, then the corresponding other torque is increased.

[0076] Although the invention has been fully described above with reference to preferred embodiments, the invention is not limited thereto and can be modified in various ways and methods.

Claims

1. An electric drive device (10) for a vehicle (F), comprising: - A first electric drive unit (E1) that can be mounted on the front axle of the vehicle; - A second electric drive unit (E2) that can be mounted on the rear axle of the vehicle (F); A control device (SE), connected to the first electric drive unit (E1) and the second electric drive unit (E2), and configured to: acquire a first operating temperature (T1) of the first electric drive unit (E1) and a second operating temperature (T2) of the second electric drive unit (E2), and control the generation of a first torque (M1) on the first electric drive unit (E1) and / or a second torque (M2) on the second electric drive unit (E2) based on the vehicle's driving conditions and / or based on the first operating temperature (T1) and / or the second operating temperature (T2), wherein the torque to which the first torque (M1) or the second torque (M2) belongs, if its operating temperature exceeds a predetermined value, can be reduced; and if the operating temperature to which the corresponding other torque (M1) or the second torque (M2) belongs is less than the predetermined value, then the corresponding other torque can be increased. The control device (SE) is configured to: generate a first difference (dT1) between the maximum limit temperature and the current temperature for the first electric drive device (E1) and / or a second difference (dT2) between the maximum limit temperature and the current temperature for the second electric drive device (E2), and deduce from these values ​​a reserve of torque to be generated in the respective drive devices (E1, E2). Specifically, by comparing thermal reserves, information is obtained about which drive unit currently has a smaller temperature reserve. Then, the current thermal trim signal can be further used for adjustment to set the desired trim, which can reflect the different torque distribution on the drive unit.

2. The electric drive device (10) according to claim 1, wherein the predetermined value includes a first limit value for the first operating temperature (T1) and a second limit value for the second operating temperature (T2).

3. The electric drive device (10) according to claim 1 or 2, wherein the electric drive device comprises: A first temperature sensor device (TS1) for the first electric drive unit (E1) is capable of detecting the first operating temperature (T1) and transmitting it to the control device (SE); and a second temperature sensor device (TS2) for the second electric drive unit (E2) is capable of detecting the second operating temperature (T2) and transmitting it to the control device (SE).

4. The electric drive device (10) according to claim 1 or 2, the electric drive device includes an adjustment device (RE) which is capable of adjusting the torque distribution between the first electric drive device (E1) and the second electric drive device (E2).

5. The electric drive device (10) according to claim 1 or 2, wherein the control device (SE) is configured to influence the first operating temperature (T1) and / or the second operating temperature (T2) by generating torque distribution, so as to keep the first operating temperature and / or the second operating temperature below the respective limit values.

6. A method for operating an electric drive device (10) for a vehicle (F), comprising the following steps: - Provide (S1) the electric drive device (10) according to any one of claims 1 to 5; - Obtain (S2) the first operating temperature (T1) of the first electric drive device (E1) and the second operating temperature (T2) of the second electric drive device (E2). - Based on the vehicle's driving conditions and / or based on the first operating temperature (T1) and / or the second operating temperature (T2), the control device (SE) controls (S3) the generation of the first torque (M1) on the first electric drive unit (E1) and / or the second torque (M2) on the second electric drive unit (E2), wherein the torque of the first torque (M1) or the second torque (M2) whose operating temperature exceeds a predetermined value is reduced, and if the operating temperature of the corresponding other torque of the first torque (M1) or the second torque (M2) is less than the predetermined value, then the corresponding other torque is increased.

7. The method of claim 6, wherein the current temperature and maximum limit temperature and / or maximum achievable torque and minimum achievable torque are obtained for the first electric drive device (E1) and / or for the second electric drive device (E2).

8. The method of claim 7, wherein a first difference (dT1) between the maximum limit temperature and the current temperature for the first electric drive device (E1) and / or a second difference (dT2) between the maximum limit temperature and the current temperature for the second electric drive device (E2) are formed, and reserves of torque to be generated in the respective drive devices (E1, E2) are obtained therefrom.

9. The method of claim 8, wherein the adjustment deviation (e) is obtained by the respective drive unit (E1, E2) from the difference between a predetermined temperature difference (dTdes) between the two drive units relative to each other and the corresponding difference (dT1, dT2) of the drive units, wherein the predetermined temperature difference (dTdes) represents a weighted average for the utilization of the reserve, wherein the adjustment deviation (e) is converted into a torque distribution between the drive units (E1, E2) and / or the adjustment deviation is set by an adjustment device (RE).

10. The method according to claim 9, wherein the regulating device (RE) is pre-given a characteristic curve (KL) for distributing the torque on the drive devices (E1, E2).

11. The method according to any one of claims 6 to 10, wherein the first operating temperature (T1) and / or the second operating temperature (T2) are affected by the resulting torque distribution in order to keep the first operating temperature and / or the second operating temperature below their respective limit values.

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