METHOD FOR OPERATING A DRIVE DEVICE AND CORRESPONDING HYBRID DRIVE DEVICE

Abstract

The invention relates to a method for operating a hybrid drive device (2) which has an internal combustion engine (3) and an electric machine (4) which can be or is operatively connected to the internal combustion engine (3) and can be operated as a generator, wherein in a normal operating mode a temperature of the electric machine (4) is determined by means of a temperature sensor (14), and operation of the electric machine (4) is permitted only if the temperature is lower than a predefined maximum temperature. There is provision here that in the event of a defect in the temperature sensor (14) an emergency operating mode is carried out in which operation of the electric machine (4) is permitted only with limited power, limited torque and/or over a limited time period. The invention further relates to a hybrid drive device (2).

Claims

1.-10. (canceled)

11. A method for operating a hybrid drive device including an internal combustion engine and an electric machine which is operatively connectable or operatively connected to the internal combustion engine and which can be operated as a motor and as a generator, said method comprising: allowing operation of the electric machine when a temperature of the electric machine as determined by a temperature sensor is less than a predefined maximum temperature; and initiating an emergency operating mode of the electric machine when detecting a defect of the temperature sensor to thereby permit operation of the electric machine only with limited power, limited torque and/or for a limited time span.

12. The method of claim 11, further comprising preventing a shutdown of the internal combustion engine, when the emergency operating mode is initiated and an ignition starter switch is in a normal operating position.

13. The method of claim 12, wherein the internal combustion engine is provided with a power supply, when the ignition starter switch is in the normal operating position.

14. The method of claim 11, wherein the limited torque is less than a maximum torque and/or a continuous torque of the electric machine.

15. The method of claim 11, wherein the limited time span is selected such that the temperature of the electric machine remains below the maximum temperature even when the electric machine is operated at maximum torque.

16. The method of claim 11, wherein at least one parameter selected from the group consisting of the limited power, the limited torque, and the limited time span is determined as a function of at least one environmental variable.

17. The method of claim 11, wherein the at least one environmental variable, is an ambient temperature.

18. The method of claim 11, further comprising barring operation of the electric machine for a specific downtime after operating the electric machine for certain time span.

19. The method of claim 18, further comprising determining the downtime as a function of an operating torque and/or an operating time during preceding operation of the electric machine.

20. The method of claim 11, wherein the electric machine is operated in the emergency operating mode as a generator for supporting an on-board electrical system.

21. The method of claim 11, wherein the electric machine is used in the emergency operating mode for starting the internal combustion engine.

22. A hybrid drive device, comprising: an internal combustion engine; an electric machine operatively connectable to the internal combustion engine and configured for operation as a motor and as a generator; and a temperature sensor determining in a normal operating mode a temperature of the electric machine, with the electric machine being permitted to operate only when the temperature is less than a predefined maximum temperature, wherein an emergency operating mode of the electric machine is initiated when detecting a defect of the temperature sensor so as to permit operation of the electric machine only with limited power, limited torque and/or for a limited time span.

23. The hybrid drive device of claim 22, further comprising an ignition starter switch configured such that in a normal operating position of the ignition starter switch, a shutdown of the internal combustion engine is prevented, when the emergency operating mode of the electric machine is initiated.

24. The hybrid drive device of claim 22, further comprising a power supply feeding the internal combustion engine with power, when the ignition starter switch is in the normal operating position.

25. The hybrid drive device of claim 22, wherein the limited torque is less than a maximum torque and/or a continuous torque of the electric machine.

26. The hybrid drive device of claim 22, wherein the limited time span is selected such that the temperature of the electric machine remains below the maximum temperature even when the electric machine is operated at maximum torque.

27. The hybrid drive device of claim 22, further comprising an on-board electrical system, said electric machine being operated in the emergency operating mode as a generator for supporting the on-board electrical system.

28. The hybrid drive device of claim 22, further comprising a control unit operably connected to the temperature sensor and configured to initiate the emergency operating mode, when detecting the defect of the temperature sensor.

Description

[0026] The invention will be explained in greater detail hereinafter with reference to the exemplary embodiments illustrated in the drawing, without limiting the invention. The sole

[0027] FIGURE shows a schematic illustration of a drive train of a motor vehicle with a hybrid drive device.

[0028] The FIGURE shows a schematic illustration of a drive train 1 of a motor vehicle, which is not shown in greater detail and includes a hybrid drive device 2. The hybrid drive device 2 includes an internal combustion engine 3 and an electric machine 4, the latter being connected via a power electronics 5 to an energy store 6 or a high voltage on-board electrical system. In the embodiment shown here, the internal combustion engine 3 and the electric machine 4 are rigidly connected with one another via a connection shaft 7. Provision may, of course, be made to provide a separating clutch (not shown) in the connection shaft 7 and therefore in the operative connection between the internal combustion engine 3 and the electric machine 4 for separating the internal combustion engine 3 from the electric machine 4.

[0029] The electric machine 4 is connected preferably rigidly and/or permanently with an output shaft 8 of the hybrid drive device 2. The output shaft is coupled via a starting clutch 9 with a gearbox 10 of the drive train 1. An operative connection between the starting clutch 9 and the wheels 11 of the drive train 1 or the motor vehicle is established via the gearbox 10. A differential gear 12 can be provided in the operative connection between the gearbox 10 and the wheels 11.

[0030] The electric machine 4 or the power electronics 5 is controlled by a control unit 13. A temperature sensor 14 of the electric machine 4 is connected to the control unit. In a normal operating mode of the hybrid drive device 2, provision is now being made for determination of a temperature of the electric machine 4 by the temperature sensor 14. Operation of the electric machine 4 is permitted only when the temperature is less than a predetermined maximum temperature. In addition or as an alternative, provision may also be made for the control unit 13 to only permit a power which is less than a maximum power that is calculated in particular on the basis of the temperature determined by the temperature sensor 14. The same approach is applicable for the torque of the electric machine 4, with a maximum torque being determined on the basis of the temperature.

[0031] In the event a defect of the temperature sensor 14 is detected, in particular by the control device 13, a changeover is effected from the normal operating mode to an emergency operating mode. In the latter, operation of the electrical machine 4 is permitted only with limited power, limited torque and/or for a certain time span. With such a procedure, excessively high temperature of the electric machine 4 is being prevented, but at the same time at least limited operation of the electric machine 4 is still permitted. In the emergency operating mode, the electric machine 4 is used, for example, to start the internal combustion engine 3. In addition or as an alternative, the electric machine 4 can be used as a generator for supporting the on-board electrical system. Thus, in spite of the defective temperature sensor 14, at least a restricted driving operation of the motor vehicle is rendered possible.