METHOD FOR OPERATING A DRIVE DEVICE FOR A MOTOR VEHICLE AND CORRESPONDING DRIVE DEVICE

Abstract

A method for operating a drive device for a motor vehicle with an internal combustion engine and a dual clutch transmission. In a starting operation of the drive device directed at a startup of the motor vehicle, an electric machine coupled to a first input shaft is used, when the first shift clutch is at least partially engaged and the first sub-transmission is disengaged and when the second shift clutch is at least partially engaged and the second sub-transmission is engaged, for providing at the output shaft a starting torque used for starting the internal combustion engine and a drive torque directed at the startup of the motor vehicle, and/or in that, in the starting operation, the internal combustion engine is operated, when the second shift clutch is at least partially engaged and the second sub-transmission is engaged.

Claims

1. A method for operating a drive device for a motor vehicle with an internal combustion engine and a dual clutch transmission, wherein the dual clutch transmission has a first input shaft, a second input shaft, and an output shaft, and the first input shaft is connected via a first sub-transmission and the second input shaft is connected via a second sub-transmission to the output shaft, and wherein the internal combustion engine is connected via a first shift clutch to the first input shaft and via a second shift clutch to the second input shaft, comprising: in a starting operation of the drive device directed at a startup of the motor vehicle, an electric machine coupled to the first input shaft is used, when the first shift clutch is at least partially engaged and the first sub-transmission is disengaged, and when the second shift clutch is at least partially engaged and the second sub-transmission is engaged, for providing at the output shaft a starting torque used for starting the internal combustion engine and a drive torque directed at startup of the motor vehicle, and/or wherein, in the starting operation, the internal combustion engine is operated, when the second shift clutch is at least partially engaged and the second sub-transmission is engaged, for driving an electric generator and for providing the drive torque at the output shaft, and electrical energy supplied by means of the generator is used for the additional driving of the output shaft by an electric motor coupled to the output shaft.

2. The method according to claim 1, wherein, in an auxiliary assembly operation, at least one auxiliary assembly is driven by the electric machine when the shift clutch is disengaged and the first sub-transmission is disengaged.

3. The method according to claim 1, wherein, when there is a switch from the auxiliary assembly operation to the starting operation, the first shift clutch for starting the internal combustion engine is at least partially engaged and the second shift clutch, when the second sub-transmission is engaged, is at least partially engaged.

4. The method according to claim 1, wherein the engaging of the second shift clutch occurs after the engaging of the first shift clutch.

5. The method according to claim 1, wherein, in the starting operation after starting the internal combustion engine, the drive torque is provided at least intermittently by the internal combustion engine and the electric machine.

6. The method according to claim 1, wherein, as a first sub-transmission, a sub-transmission with a smaller minimum gear ratio than that of the second sub-transmission is used.

7. The method according to claim 1, wherein, for a gear shift of the dual clutch transmission during the starting operation, the first shift clutch is disengaged, the first sub-transmission is engaged, and subsequently the first shift clutch is engaged and the second shift clutch is disengaged.

8. The method according to claim 1, wherein, in the starting operation during the driving of the output shaft by the electric motor, the second shift clutch is only partially engaged.

9. The method according to claim 1, wherein, in the starting operation, the generator is coupled to the internal combustion engine in a rotationally rigid manner or the electric machine is used as a generator.

10. A drive device for a motor vehicle, comprising: an internal combustion engine and a dual clutch transmission, wherein the dual clutch transmission has a first input shaft, a second input shaft, and an output shaft, and the first input shaft is connected via a first sub-transmission and the second input shaft is connected via a second sub-transmission to the output shaft, and wherein the internal combustion engine is connected via a first shift clutch to the first input shaft and via a second shift clutch to the second input shaft, wherein, in a starting operation of the drive device directed at a startup of the motor vehicle, an electric machine coupled to the first input shaft is used, when the first shift clutch is at least partially engaged and when the first sub-transmission is disengaged and when the second shift clutch is at least partially engaged and the second sub-transmission is engaged, for providing at the output shaft a starting torque used for starting the internal combustion engine and a drive torque directed at the startup of the motor vehicle, and/or wherein, in the starting operation, the internal combustion engine, when the second shift clutch is at least partially engaged and the second sub-transmission is engaged, is operated for driving an electric generator and for providing the drive torque at the output shaft, and electrical energy supplied by the generator is used for the additional driving of the output shaft by an electric motor coupled to the output shaft.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0040] The invention will be explained below in more detail on the basis of the exemplary embodiments illustrated in the drawing, without any limitation of the invention thereby occurring. In this case, the FIGURE(S) show:

[0041] FIG. 1 a schematic illustration of a drive device for a motor vehicle, wherein an auxiliary assembly is driven by means of an electric machine.

DETAILED DESCRIPTION

[0042] FIG. 1 shows a schematic illustration of a drive device 1 for a motor vehicle. The drive device 1 has a internal combustion engine 2 as well as a dual clutch transmission 3. The dual clutch transmission 3 is equipped, in turn, with a first input shaft 4, which can be coupled via a first sub-transmission 5 to an output shaft 6 of the dual clutch transmission 3, namely, when the first sub-transmission 5 is coupled; that is, a gear is engaged at the first sub-transmission 5. Furthermore, the dual clutch transmission 3 is equipped with a second input shaft 7, which is connected via a second sub-transmission 8 to the output shaft 6. The second input shaft 7 is operatively coupled to the output shaft 6 when the second sub-transmission is engaged; that is, a gear is engaged at the second sub-transmission 8.

[0043] The first input shaft 4 can be coupled to the internal combustion engine 2 via a first shift clutch 9. Analogously, for this purpose, the second input shaft 7 can be coupled to the internal combustion engine 2 via a second shift clutch 10. For example, the shift clutches 9 and 10 are each connected at the input end to the internal combustion engine 2, preferably rigidly and/or permanently. At the output end, the shift clutches 9 and 10 are coupled to the respective input shaft 4 or 7, namely, rigidly and permanently. It can be provided that, between the shift clutches 9 and 10 and the internal combustion engine 2, there is another shift clutch 11. Said clutch can be designed as a starting clutch. The shift clutch 11 is optional, however.

[0044] The drive device 1 is equipped with an auxiliary drive 12, which, in turn, has at least one auxiliary assembly 13. The auxiliary assembly 13 can be driven by means of the internal combustion engine 2. For this purpose, said auxiliary assembly is coupled to the first input shaft 4, preferably rigidly and/or permanently. In the exemplary embodiment illustrated here, the auxiliary assembly 13 is connected to the first input shaft 4 via a gear step 14. Further illustrated are an electric machine 15, an electric generator 16, and an electric motor 17.

[0045] It may be provided that the electric machine 15, the generator 16, and the motor 17 are all present. It may also be provided, however, that the electric machine 15 is present, whereas the generator 16 and the motor 17 are dispensed with. Conversely, it can be provided that the electric machine 15 is dispensed with, but the generator 16 and the motor 17 are components of the drive device 1. This notwithstanding, all of the named elements are included in the scope of this description.

[0046] The electric machine 15 is coupled to the first input shaft 4, preferably rigidly and/or permanently, in particular, via a gear step 18. The electric machine 15 serves, among other things, for driving the auxiliary assembly 13, in particular, when the internal combustion engine 2 is at a standstill. The generator 16 can be driven by means of the internal combustion engine 2. Said generator is connected, for example, via the shift clutch 11 oralternativelydirectly to the internal combustion engine 2 or coupled to it. The motor 17, in contrast, serves for driving the output shaft 6, and, for this purpose, is coupled to it, preferably rigidly and/or permanently.

[0047] It can then be provided, in a starting operation of the drive device directed at a startup of the motor vehicle 1, when the first shift clutch 9 is at least partially engaged and the first sub-transmission 5 is disengaged, and when the second shift clutch 10 is at least partially engaged and the second sub-transmission 8 is engaged, to use the electric machine 15 coupled to the first input shaft 4 for providing a starting torque used for starting the internal combustion engine 2 and a drive torque directed at startup of the motor vehicle at the output shaft 6.

[0048] More preferably, is it provided that, when the internal combustion engine 2 is at a standstill, an auxiliary assembly operation is initially carried out, in which the auxiliary assembly 13 is driven by means of the electric machine 15, with the first shift clutch 9 being disengaged and the first sub-transmission 5 being disengaged. During the startup of the motor vehicle, the auxiliary assembly 13 is to be further driven by means of the electric machine 15. At the same time, the electric machine 15 serves for starting the internal combustion engine 2. For this reason, the first shift clutch 9 is at least partially engaged, so that, at the internal combustion engine 2, the starting torque is provided by means of the electric machine 15. In addition, the second sub-transmission 8 is engaged, that is, a gear is engaged at the second sub-transmission 8 if this was not already the case.

[0049] Afterwards, the second shift clutch 10 is likewise partially engaged, so that the output shaft 6 is driven by means of the electric machine 15. In this starting operation, therefore, the auxiliary assembly 13 is further driven by means of the electric machine 15, and, at the same time, the torque provided by the electric machine 15 is employed for starting the internal combustion engine 2 and for startup of the motor vehicle. Accordingly, when the auxiliary assembly 13 is further operated, a rapid startup of the motor vehicle is realized.

[0050] Additionally or alternatively, it can be provided in the starting operation that, when the second shift clutch 10 is at least partially engaged and the second sub-transmission 8 is engaged, the internal combustion engine 2 is operated for driving the electric generator 16 and for providing the drive torque at the output shaft 6, and energy supplied by means of the generator 16 is used for the additional driving of the output shaft 6 by way of the electric motor 17 coupled to the output shaft 6.

[0051] In other words, a part of the torque provided by the internal combustion engine 2 is transmitted directly via the dual clutch transmission 3 and is available at the output shaft 6. Another part of the torque provided by the internal combustion engine 2 is taken up by the generator 16 for supplying electrical energy. The electrical energy supplied in this way is used for driving the motor 17, which, in addition, drives the output shaft 6. In this regard, only a part of the torque provided by the internal combustion engine 2 is transmitted via the dual clutch transmission 3, in particular, via the second shift clutch 10.

[0052] This ultimately means that, at the output shaft 6, it is possible to provide a drive torque that is greater than a selection torque of the second shift clutch 10. It should be noted that the described procedural approach can also be carried out by means of the first shift clutch 9 or the first sub-transmission 5. The exemplary embodiment illustrated here was focused on the second shift clutch 10 and the second sub-transmission 8 solely by way of example.