Hybrid drivetrain having a combustion powertrain and an electrical powertrain

Abstract

A hybrid drivetrain includes an output element, a combustion powertrain, an electrical powertrain, and a torque-transmitting, fixed-speed reduction gearing connected to the output element for reducing a speed of the internal combustion engine and the electric machine. The combustion powertrain has an internal combustion engine with a drive shaft for delivering a first torque, a generator with a generator shaft for converting the first torque into electrical energy, a variable transmission arranged to variably transmit the first torque, and a torque clutch for connecting and disconnecting transmission of the first torque between the internal combustion engine and the output element. The electrical powertrain has an electric machine with a rotor shaft for delivering a second torque. In an example embodiment, the torque-transmitting, fixed-speed reduction gearing has a direct combustion input stage for the combustion powertrain and a direct electrical input stage for the electrical powertrain.

Claims

1.-10. (canceled)

11. A hybrid drivetrain comprising: an output element; a combustion powertrain comprising: an internal combustion engine comprising a drive shaft for delivering a first torque; a generator comprising a generator shaft for converting the first torque into electrical energy; a variable transmission arranged to variably transmit the first torque; and a torque clutch for connecting and disconnecting transmission of the first torque between the internal combustion engine and the output element; an electrical powertrain comprising: an electric machine comprising a rotor shaft for delivering a second torque; and a torque-transmitting, fixed-speed reduction gearing connected to the output element for reducing a speed of the internal combustion engine and the electric machine.

12. The hybrid drivetrain of claim 11, wherein the torque-transmitting, fixed-speed reduction gearing comprises a direct combustion input stage for the combustion powertrain and a direct electrical input stage for the electrical powertrain.

13. The hybrid drivetrain of claim 12, wherein the variable transmission of the combustion powertrain is offset in parallel or axially overlaps the internal combustion engine.

14. The hybrid drivetrain of claim 12, wherein only a single-stage, fixed-speed torque transmission drive is provided as an axial extension of the drive shaft for torque transmission by the variable transmission to the output element.

15. The hybrid drivetrain of claim 12, further comprising a torque clutch with three switching states on an input side of the variable transmission.

16. The hybrid drivetrain of claim 11, wherein the variable transmission of the combustion powertrain is offset in parallel or axially overlaps the internal combustion engine.

17. The hybrid drivetrain of claim 16, wherein only a single-stage, fixed-speed torque transmission drive is provided as an axial extension of the drive shaft for torque transmission by the variable transmission to the output element.

18. The hybrid drivetrain of claim 16, further comprising a torque clutch with three switching states on an input side of the variable transmission.

19. The hybrid drivetrain of claim 11, wherein only a single-stage, fixed-speed torque transmission drive is provided as an axial extension of the drive shaft for torque transmission by the variable transmission to the output element.

20. The hybrid drivetrain of claim 19, further comprising a torque clutch with three switching states on an input side of the variable transmission.

21. The hybrid drivetrain of claim 11, further comprising a torque clutch with three switching states on an input side of the variable transmission.

22. The hybrid drivetrain of claim 11, wherein the drive shaft, the generator shaft and the rotor shaft point in the same axial direction.

23. The hybrid drivetrain of claim 11, wherein the torque clutch is arranged for at least two of the following three switching states: connecting the generator and the internal combustion engine to the output element in a torque-transmitting manner; interrupting a combustion-side torque transmission to the output element and connecting the generator to only the internal combustion engine in a torque-transmitting manner; and connecting only the generator or only the internal combustion engine to the output element in a torque-transmitting manner.

24. The hybrid drivetrain of claim 11, further comprising a torque transmission unit with a ring gear, wherein the generator shaft is connected to the variable transmission in a torque-transmitting manner by the torque transmission unit.

25. The hybrid drivetrain of claim 24, wherein the torque transmission unit connects the generator shaft to the variable transmission in a single stage, speed-reducing manner.

26. The hybrid drivetrain of claim 11, wherein the variable transmission is designed as a belt transmission having a continuously adjustable translation ratio.

27. The hybrid drivetrain of claim 26, wherein the generator and the internal combustion engine are connected on an input side of the transmission in a torque-transmitting manner.

28. The hybrid drivetrain of claim 11, wherein the fixed-speed reduction gearing is designed as a spur gear differential.

29. The hybrid drivetrain of claim 11, wherein the torque-transmitting, fixed-speed reduction gearing is designed as a differential or is structurally integrated into a differential.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The disclosure described above is explained in detail below based on the relevant technical background with reference to the associated drawings, which show example embodiments. The disclosure is in no way restricted by the purely schematic drawings, although it should be noted that the drawings are not dimensionally accurate and are not suitable for defining proportions. In the following,

[0075] FIG. 1 shows a hybrid drivetrain in a motor vehicle as a rear-wheel drive;

[0076] FIG. 2 shows sections of a combustion powertrain with a double switching element;

[0077] FIG. 3 shows sections of a hybrid powertrain with a common receiving shaft on the reduction gearing;

[0078] FIG. 4 shows a section of a hybrid powertrain with a common input shaft and separate combustion input stage and electrical input stage;

[0079] FIG. 5 shows a hybrid drivetrain with belt transmission;

[0080] FIG. 6 shows a section of an electrical powertrain with two reduction stages for the electric machine; and

[0081] FIG. 7 shows a hybrid drivetrain with a ring gear for the generator.

DETAILED DESCRIPTION

[0082] FIG. 1 shows a hybrid drivetrain 1 in a motor vehicle 24. All components are shown schematically. The generator 8 is designed as a starter generator (for driving the internal combustion engine 6) or as a motor generator (for driving the output element 4, 5). The internal combustion engine 6 (combustion engine, combustor, ICE) is shown as a 6-cylinder internal combustion engine, but can also have a different number of cylinders. However, the advantage of the hybrid drivetrain's axial compactness is particularly large if an internal combustion engine 6 is used that has a relatively long axial construction, for example a 6-cylinder in-line engine.

[0083] In FIG. 1 the hybrid drivetrain 1 is shown in a motor vehicle 24 as a rear-wheel drive, i.e., with a left drive wheel 4 and a right drive wheel 5 of the rear axis 31 as an output element. The hybrid drivetrain 1 is optionally arranged transversely to the longitudinal axis 26. This means that here the combustion axis 27, the generator shaft 28 and the rotor axis 29 are arranged transversely to the longitudinal axis 26 and parallel to the rear axis 31. Alternatively, the hybrid drivetrain 1 is arranged longitudinally or at least one motor axis is arranged transversely and at least one other motor axis is arranged longitudinally. The hybrid drivetrain 1 is also optionally arranged behind the driver's cab 25 and independently thereof. Alternatively, the hybrid drivetrain 1 is at the front, i.e., in front of the driver's cab at or above the front axis 32.

[0084] The hybrid drivetrain 1 includes a combustion powertrain 2 and an electrical powertrain 3, each of which is bordered here by a dashed box. The electrical powertrain 3 has an electric machine 13 with a rotor shaft 14 and is connected by means of an electric input stage 17 in a torque-transmitting manner to the reduction gearing 15 with the output element 4, 5 to the rear axis 31, which is constructed with a differential 42, for example a bevel gear differential. The internal combustion powertrain 2 comprises an internal combustion engine 6, which here is shown schematically as a 6-cylinder piston motor with a clockwise rotating drive shaft 7 (see first direction of rotation 20) is shown, and furthermore a generator 8 with a counterclockwise rotating generator shaft 9 (see second direction of rotation 21), and a variable transmission 10.

[0085] The internal combustion engine 6 can be connected to the input side 33 of the variable transmission 10 in a torque-transmitting manner by means of a dual-mass flywheel 30 via a torque transmission drive 18 designed here as a traction mechanism drive with, for example, a chain as a traction means 19. The generator 9 is also connected to the input side 33 of the variable transmission 10 in a torque-transmitting manner by means of a one-stage (here spur gear) torque transmission unit 23. In contrast to the generator 8, the internal combustion engine 6 can be separated from the input side 33 of the variable transmission 10 by means of a (second) torque clutch 12, for example a wedge clutch. The output side 34 of the variable transmission 10 can be connected to the reduction gearing 15 via a combustion input stage 16. Here, a (first) torque clutch 11 is provided, so that the combustion powertrain 2 can be completely separated from the output 4, 5. The first torque clutch 11 is also preferably slip-free, for example as a dog clutch. Optionally, only the first torque clutch 11 or only the second torque clutch 12 is provided.

[0086] FIGS. 2 to 7 show variants of the architecture of a hybrid drivetrain 1, which can be used in a motor vehicle 24 as shown in FIG. 1 to replace the corresponding components there. Therefore, reference is made to the description of FIG. 1. However, this is not to be understood as limiting. For example, the hybrid drivetrain 1 can be used to drive a front axis 32 or for all-wheel drive.

[0087] FIG. 2 shows a section of a combustion powertrain 2 of a hybrid drivetrain 1 as shown, for example, in FIG. 1. On the one hand, a double shift element locally combines the first torque clutch 11 and the second torque clutch 12. For this purpose, the generator 8 is guided through an input side 33 of the variable transmission 10 designed as a hollow shaft and can be switched to the input side 33 and separately switched to the internal combustion engine 6 (here a section of the torque transmission drive 18 can be seen with traction means 19) or both be separated. Likewise, the internal combustion engine 6 can be connected and disconnected separately to both, i.e., the generator 8 and the variable transmission 10. On the other hand, the variable transmission 10 is indicated here as a belt transmission with a belt 35, which enables a stepless transmission between the input side 33 and the output side 34 (see FIG. 1), so that the internal combustion engine 6 can be operated in an always optimal speed range.

[0088] FIG. 3 shows a section of a hybrid drivetrain 1. Here the reduction gearing 15 is integrated into a differential 42, which is designed here as a spur gear differential. The reduction gearing 15, i.e., the electrical input stage 17 and the combustion input stage 16, and the at least one (first) reduction stage 37 may form a structural unit with the differential 42. The differential 42 includes a left compensation stage 38 for torque transmission to the left drive wheel 4 (see FIG. 1) and a right compensation stage 39 for torque transmission to the right drive wheel 5. The compensation stages 38, 39 distribute a torque introduced via the reduction gearing 15 to the left drive wheel 4 and the right drive wheel 5, for example conventionally, after a respective decrease in torque or decrease in speed. In one embodiment, one (in this exemplary embodiment, the same) reduction ratio based on the speed of less than 1 is also integrated in the compensation stages 38, 39. The compensation stages 38 and 39 are not necessarily identical and the left compensation stage 38 is not necessarily arranged on the left of the right compensation stage 39.

[0089] The reduction gearing 15 here in FIG. 3 has a common receiving shaft 36 with a single spur gear. This receiving shaft 36 forms both the combustion input stage 16 (for example with the output side 34 of the variable transmission 10, see FIG. 1) and the electrical input stage 17. The electrical input stage 17 also has an intermediate wheel 41, which serves to produce a desired center distance. The input stages 16 and 17 are followed by the (here only common first) reduction stage 37, in which a fixed ring gear has been selected purely by way of example, the receiving shaft 36 enters the torque via a sun gear, and the left compensation stage 38 and the right compensation stage 39 in each case are movable with a planetary carrier. The left compensation stage 38 and the right compensation stage 39 can be driven via a planetary carrier and the left drive wheel 4 or the right drive wheel 5 are connected in a torque-transmitting manner by means of the respective sun gear. It should be explicitly pointed out that the differential 42 shown, which is designed as a spur gear differential, is selected only as an example and can be replaced by another suitable connection.

[0090] FIG. 4 shows a section of a hybrid drivetrain 1, which is almost identical to the illustration in FIG. 3 for the sake of clarity and in this respect reference is made to the preceding description. In contrast to the embodiment according to FIG. 3, a receiving shaft 36 with two spur gears is shown, wherein one of the spur gears forms the combustion input stage 16 (on the right in the illustration) and the other spur gear forms the electrical input stage 17. An intermediate gear 41 in the electrical input stage 17 has been omitted here.

[0091] FIG. 5 shows a hybrid drivetrain 1, in which, for the sake of clarity, the part of the detail shown in FIG. 4 is identical to that shown there, and in this respect reference is made to the preceding description. Furthermore, the configuration of the electrical powertrain 3 is mirrored identically and the combustion powertrain 2 is similar to that shown in FIG. 1 and in this respect reference is made to the associated description. In contrast to the configuration of the internal combustion powertrain 2 according to FIG. 1, the internal combustion engine 6 and the generator 8 are arranged mirrored here, wherein the axial direction 22 of the drive shaft 7 and the generator shaft 9, but also the first direction of rotation 20 of the drive shaft 7 and the second direction of rotation 21 of the generator shaft 9, are the same. This is the case because here the torque transmission drive 18 of the internal combustion engine 6 as well as the torque transmission unit 23 are designed as a single-stage spur gear. A direction of rotation in the same direction in the torque transmission is thus entered on the input side 33 of the variable transmission 10. The variable transmission 10 is designed here as a belt transmission, e.g., as a CVT.

[0092] FIG. 6 shows the electrical powertrain 3 and the reduction gearing 15 and the differential 42 of the hybrid powertrain 1, as can be used in the architecture of the hybrid drivetrain 1 according to the embodiment in FIG. 5 to replace the components shown. The electric machine 13 is designed to rotate at high speed so that the speed range is significantly higher than is desired for the integrated receiving shaft 36 for an integrated combustion input stage 16. Therefore, a second reduction stage 40 is provided here as a preliminary stage to the first reduction stage 37, which, however, is only set up for reducing the speed of the high-speed electric machine 13 and, for this purpose, is connected to the first reduction stage 37 of the reduction gearing 15 in a torque-transmitting manner. In the selected configuration, the torque input of the electric machine 13 initially runs via a single-stage electrical input stage 17, as is the case, for example, in the architecture of the hybrid drivetrain 1 according to FIGS. 4 and 5. Above, the torque runs into the second reduction stage 40, namely into a rotationally fixed connected (second) sun gear, then onto the (second) planetary gears, which are mounted on a planetary carrier that is connected to the common receiving shaft 36 in a rotationally fixed manner, further onto a (second) ring gear on the (first) planet carrier of the first reduction stage 37. The first reduction stage 37 is based on the combustion powertrain 2 identical to that in FIGS. 4 and 5. For the sake of clarity, the left compensation stage 38 and the right compensation stage 38 are also designed as described above.

[0093] For the sake of clarity, FIG. 7 shows an almost identical configuration of the hybrid drivetrain 1, as shown in FIG. 5, in which case the generator shaft 9 of the generator 8 is connected to the input side 33 of the variable transmission 10 in a torque-transmitting manner via a single-stage torque transmission unit 23 comprising a ring gear. The second direction of rotation 21 of the generator shaft 9 is thus opposite the first direction of rotation 20 of the drive shaft 7.

[0094] With the hybrid drivetrain proposed here, a space-saving architecture that can be flexibly adapted to the respective space requirements is achieved.

TABLE-US-00001 REFERENCE NUMERALS 1 Drivetrain 2 Combustion powertrain 3 Electrical powertrain 4 Left drive wheel 5 Right drive wheel 6 Internal combustion engine 7 Drive shaft 8 Generator 9 Generator shaft 10 Variable transmission 11 First torque clutch 12 Second torque clutch 13 Electric machine 14 Rotor Shaft 15 Reduction gearing 16 Combustion input stage 17 Electrical input stage 18 Torque transmission drive 19 Traction means 20 First direction of rotation 21 Second direction of rotation 22 Axial direction 23 Torque transmission unit 24 Motor vehicle 25 Driver's cab 26 Longitudinal axis 27 Combustion axis 28 Generator axis 29 Rotor axis 30 Dual-mass flywheel 31 Rear axis 32 Front axis 33 Input side 34 Output side 35 Belt 36 Receiving shaft 37 First reduction stage 38 Left compensation stage 39 Right compensation stage 40 Second reduction stage 41 Intermediate gear 42 Differential