Power Shiftable Hybrid Transmission, Drivetrain and Motor Vehicle

Abstract

A hybrid transmission (20) for a motor vehicle drive train (12) with an internal combustion engine (14), a first electric prime mover (16), and a second electric prime mover (18), includes: a first transmission input shaft (24) for a first sub-transmission coaxially drivingly connectable to the internal combustion engine and/or drivingly connectable to the second electric prime mover in an axially parallel manner; a second transmission input shaft (26) for a second sub-transmission drivingly connectable to the first electric prime mover in an axially parallel manner; a countershaft (28); idler gears and fixed gears arranged in multiple gear set planes for forming gear steps; and multiple gear change devices including shift elements (A-E) for engaging the gear steps. All even gear steps are associated with one sub-transmission and all odd gear steps are associated with the other sub-transmission such that all electric-machine gear steps are power shiftable.

Claims

1-15: (canceled)

16. A hybrid transmission (20) for a motor vehicle drive train (12) with an internal combustion engine (14), a first electric prime mover (16), and a second electric prime mover (18), the hybrid transmission (20) comprising: a first transmission input shaft (24) for a first sub-transmission that is coaxially drivingly connectable to the internal combustion engine and/or drivingly connectable to the second electric prime mover in an axially parallel manner; a second transmission input shaft (26) for a second sub-transmission that is drivingly connectable to the first electric prime mover in an axially parallel manner; a countershaft (28); a plurality of idler gears and fixed gears arranged in multiple gear set planes for forming a plurality of gear steps; and a plurality of shift elements (A-E) for engaging the plurality of gear steps, wherein all even gear steps of the plurality of gear steps are associated with one of the first and second sub-transmissions, and all odd gear steps of the plurality of gear steps are associated with the other of the first and second sub-transmissions.

17. The hybrid transmission (20) of claim 16, further comprising a connecting clutch configured for drivingly connecting the first sub-transmission and the second sub-transmission.

18. The hybrid transmission (20) of claim 16, further comprising an internal combustion engine clutch (K0) configured for drivingly connecting the internal combustion engine (14) to the first transmission input shaft (24).

19. The hybrid transmission (20) of claim 18, wherein the internal combustion engine clutch (K0) is a friction clutch or a form-locking shift element.

20. The hybrid transmission (20) of claim 16, wherein at least two of the plurality of shift elements (A-E, K3) are configured as a double shift element (AE, DB, CK3) actuatable by a double-acting actuator.

21. The hybrid transmission (20) of claim 16, wherein the first transmission input shaft (24) and the second transmission input shaft (26) are arranged coaxially to each other; and one of the first and second transmission input shafts is a hollow shaft that at least partially encompasses the other of the first and second transmission input shafts.

22. The hybrid transmission (20) of claim 16, wherein, one or both of: a gear-forming fixed gear (32) of the first sub-transmission is configured to be drivingly operatively connected to the second electric prime mover (18); and a gear-forming fixed gear (30) of the second sub-transmission is configured to be drivingly operatively connected to the first electric prime mover (16).

23. The hybrid transmission (20) of claim 22, wherein: the gear-forming fixed gear (32) of the first sub-transmission forms the highest gear step of the first sub-transmission; and the gear-forming fixed gear (30) of the second sub-transmission forms the highest gear step of the second sub-transmission.

24. The hybrid transmission (20) of claim 16, wherein a gear-forming fixed gear (30, 32) arranged at a first axial end of the hybrid transmission is configured to be drivingly connected to one or both of the first electric prime mover (16) and the second electric prime mover (18).

25. The hybrid transmission (20) of claim 24, wherein a gear-forming fixed gear (30, 32) arranged at a second axial end of the hybrid transmission opposite the first axial end is configured to be drivingly connected to one or both of the first electric prime mover (16) and the second electric prime mover (18).

26. A motor vehicle drive train (12) for a motor vehicle (10), comprising: the hybrid transmission (20) of claim 16; an internal combustion engine (14) connectable to the first transmission input shaft (24); a first electric prime mover (16) connectable to the second transmission input shaft (26); and a second electric prime mover (18) connectable to the first transmission input shaft.

27. The motor vehicle drive train (12) of claim 26, wherein one or both of the first electric prime mover (16) and the second electric prime mover (16, 18) is actuatable as one or more of: a starter generator for starting the internal combustion engine (14); a charging generator for charging an energy accumulator (22); and a generator for supplying the first or second electric prime mover in a serial traveling mode.

28. The motor vehicle drive train (12) of claim 26, wherein one or both of the second electric prime mover (18) and the internal combustion engine (14) is operable to provide a supporting force during gear changes of the first electric prime mover (16); and the first electric prime mover is operable to provide as a supporting force during gear changes of one or both of the second electric prime mover and the internal combustion engine.

29. The motor vehicle drive train (12) of claim 26, wherein one or both of the first electric prime mover (16) and the second electric prime mover (18) is arranged axially parallel to one or both of the first transmission input shaft (24) and the second transmission input shaft (26).

30. A motor vehicle (10), comprising: the motor vehicle drive train (12) of claim 26; and an energy accumulator (22) for storing energy for supplying one or both of the first electric prime mover (16) and the second electric prime mover (18).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Example aspects of the invention are described and explained in greater detail in the following with reference to a few selected exemplary embodiments in conjunction with the attached drawings, in which:

[0045] FIG. 1 shows a schematic of a motor vehicle with a motor vehicle drive train according to example aspects of the invention;

[0046] FIG. 2 shows a schematic of a hybrid transmission according to example aspects of the invention;

[0047] FIG. 3 shows a schematic of a gear shift matrix of the hybrid transmission according to example aspects of the invention from FIG. 2;

[0048] FIG. 4 shows a second variant of a hybrid transmission according to example aspects of the invention;

[0049] FIG. 5 shows a third variant of a hybrid transmission according to example aspects of the invention; and

[0050] FIG. 6 shows a fourth variant of a hybrid transmission according to example aspects of the invention.

DETAILED DESCRIPTION

[0051] Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

[0052] FIG. 1 diagrammatically shows a motor vehicle 10 having a motor vehicle drive train 12. The motor vehicle drive train 12 includes an internal combustion engine 14, a first electric prime mover 16, and a second electric prime mover 18, which are connected by a hybrid transmission 20 to a front axle of the motor vehicle 10. Drive power of the electric prime movers 16, 18 and the internal combustion engine 14 is supplied to the wheels of the motor vehicle 10 by the motor vehicle drive train 12. The motor vehicle 10 also includes an energy accumulator 22 in order to store energy, which is utilized for supplying the first electric prime mover 16 and/or the second electric prime mover 18.

[0053] A first example variant of a hybrid transmission 20 is shown in FIG. 2. The hybrid transmission 20 includes a first transmission input shaft 24, which is designed as a solid shaft in this example. The hybrid transmission 20 also includes a second transmission input shaft 26, which is designed as a hollow shaft and surrounds the first transmission input shaft 24, at least partially or in sections. A countershaft 28 is arranged axially parallel to the first transmission input shaft 24 and to the second transmission input shaft 26. The internal combustion engine 14 is connectable to the first transmission input shaft 24 by an internal combustion engine clutch K0 and is arranged coaxially to the first transmission input shaft 24. The first transmission input shaft 24 supplies drive power to a first sub-transmission of the hybrid transmission 20, which includes the odd gear steps of the hybrid transmission 20. The second transmission input shaft 26 supplies drive power to a second sub-transmission of the hybrid transmission 20, which includes the even gear steps of the hybrid transmission 20.

[0054] The hybrid transmission 20 includes five gear steps, each of which is formed by one gearwheel pair made up of an idler gear and a fixed gear. The first electric prime mover 16 is connected to the hybrid transmission 20 via a fixed gear 30 of the fourth gear step. The second electric prime mover 18 is connected to the hybrid transmission 20 via a fixed gear 32 of the fifth gear step. The fixed gears of the second and fourth gear steps are arranged on the second transmission input shaft 26. The fixed gears of the first and fifth gear steps are arranged on the first transmission input shaft 24. The third gear step is formed by a fixed gear, which is arranged at the countershaft 28, and an idler gear, which is arranged at the first transmission input shaft 24. The countershaft 28 is drivingly connected to a drive output 34 via a gearwheel pair made up of fixed gears. The drive output 34 transmits the drive power supplied to the hybrid transmission 20 onto an axle and/or driven wheels of the motor vehicle 10 (not shown).

[0055] The shift element A is arranged on the countershaft 28 and is associated with the first gear step. The shift element B is arranged on the countershaft 28 and is associated with the second gear step. The shift element C is arranged on the first transmission input shaft 24 and is associated with the third gear step. The shift element D is associated with the fourth gear step and is arranged on the countershaft 28. The shift element E is associated with the fifth gear step and is arranged on the countershaft 28. The shift elements A and E form a double shift element. The shift elements D and B form a double shift element. The shift element C forms a double shift element together with a shift element K3 of a connecting clutch. By engaging the shift element K3, the first transmission input shaft 24 can be rotationally fixed to the second transmission input shaft 26.

[0056] The internal combustion engine 14 and the first transmission input shaft 24 and the second transmission input shaft 26 are arranged on a transmission axis A1. The countershaft is arranged on a transmission axis A2. The second electric prime mover 18 is arranged on a transmission axis A4. The first electric prime mover 16 is arranged on a transmission axis A5.

[0057] FIG. 3 shows a gear shift matrix 36 of the hybrid transmission 20 from FIG. 2 and the following embodiments of hybrid transmissions 20. The first column lists the internal-combustion-engine gear steps V1 through V5 of the internal combustion engine 14 and the electric-machine gear steps E1 and E2 of the first electric prime mover 16. The gear shift matrix 36 indicates which gear steps 1 through 5 of the hybrid transmission 20 correspond to which of the internal-combustion-engine gear steps V1 through V5 and to which of the electric-machine gear steps E1 and E2.

[0058] The second to eighth columns show the engagement conditions of the internal combustion engine clutch K0 and the individual shift elements K3 and A through E, wherein an “X” indicates that the shift element and/or the internal combustion engine clutch K0 are/is engaged, i.e., drivingly connect the associated components.

[0059] For the internal-combustion-engine gear step V1, the internal combustion engine clutch K0 and the shift element A are to be engaged. For the internal-combustion-engine gear step V2, the internal combustion engine clutch K0 and the shift element K3 of the connecting clutch as well as the shift element B are to be engaged. For the internal-combustion-engine gear step V3, the internal combustion engine clutch K0 and the shift element C are to be engaged. For the internal-combustion-engine gear step V4, the internal combustion engine clutch K0, the shift element K3 of the connecting clutch as well as the shift element D are to be engaged. For the internal-combustion-engine gear step V5, the internal combustion engine clutch K0 and the shift element E are to be engaged. For the electric-machine gear step E1 of the first electric prime mover 16, the shift element B is to be engaged. For the electric-machine gear step E2 of the first electric prime mover 16, the shift element D is to be engaged.

[0060] Further electric-machine gear steps of the second electric prime mover 18 can also be established with the hybrid transmission 20. These engage similarly to the internal-combustion-engine gear steps V1 through V5, although the internal combustion engine clutch K0 is to be disengaged for the purely electric operation.

[0061] It is also understood that the gear steps of the internal combustion engine 14 and of the first and second electric prime movers 16, 18 can be utilized in combination in a hybrid mode for driving.

[0062] Therefore, driving can be carried out with both electric prime movers 16, 18 in a purely electric operation. Powershifts are possible in this purely electric operation, in that the first electric prime mover 16 supports the tractive force when a gear step change takes place for the second electric prime mover 18, and the second electric prime mover 18 supports the tractive force when a gear step change takes place for the first electric prime mover 16.

[0063] In the internal combustion engine-driven mode, therefore, the internal combustion engine clutch K0 always remains engaged. As a result, the internal combustion engine 14 is preferably always connected to the second electric prime mover 18 in the internal combustion engine-driven mode.

[0064] The following functions can be covered by the second electric prime mover 18. A start of the internal combustion engine 14 while driving under purely electric motor power is possible. The second electric prime mover 18 can be driven as a generator by the internal combustion engine 14 and ensure a supply of the main power circuit and of the onboard electronics. A serial creeping and driving forward/in reverse is possible. Here, the energy made available by the second electric prime mover 18 while acting as a generator is provided to the first electric prime mover 16 and driving takes place by the first electric prime mover 16. A support of a closed-loop control of the rotational speed of the internal combustion engine 14 can take place during coupling and during gear shifts. For example, the internal combustion engine 14 can be coupled into the gears 1, 2, 3, and 5 of the hybrid transmission 20 when the first electric prime mover 16 utilizes the gear step E1. The internal combustion engine 14 can be coupled into the gears 1, 3, 4, and 5 of the hybrid transmission 20 when the first electric prime mover 16 utilizes the gear step E2.

[0065] The second electric prime mover 18 can provide support during the unloading of the shift elements K3, A, C, and E, in that the second electric prime mover 18 operates as a generator. The generated energy can be utilized by the first electric prime mover 16 for supporting tractive force.

[0066] The following functions, in particular, can be covered by the first electric prime mover 16. An electric vehicle drive can be established for pulling away from rest and driving forward/in reverse. A support of the tractive force during gear shifts of the internal combustion engine 14 is possible. The first electric prime mover 16 can maintain the tractive force when a change takes place with the shift elements K3, A, C, E. The first electric prime mover 16 can be drivingly connected to the internal combustion engine 14 via the shift element K3 of the connecting clutch. For this purpose, additionally, the internal combustion engine clutch K0 is to be engaged. In this shift condition, the first electric prime mover 16 can start the internal combustion engine 14 or be utilized as a generator for generating power for a consumer, for example, when the vehicle is at a standstill.

[0067] A powershift from the first internal-combustion-engine gear V1 into the second internal-combustion-engine gear V2 in the hybrid mode can take place as follows. The starting point is the internal-combustion-engine gear step V1, in which the internal combustion engine clutch K0 and the shift element A are engaged. A load reduction takes place at the shift element A and a simultaneous load build-up takes place at the first electric prime mover 16. The load reduction can take place in that the internal combustion engine 14 and the second electric prime mover 18 reduce the torque or when the second electric prime mover compensates for the torque of the internal combustion engine 14 while acting as a generator, and so the sum of the torques from the internal combustion engine 14 and the second electric prime mover 18 is essentially zero. The shift element A is disengaged. The rotational speed of the internal combustion engine 14 and of the second electric prime mover 18 is reduced, and so the shift element K3 of the connecting clutch is synchronized. For this purpose, for example, the second electric prime mover 18 can operate as a generator, which is preferred, or the internal combustion engine 14 can enter the coasting condition. The shift element K3 can be engaged.

[0068] A reduction of the rotational speed of the first electric prime mover 16 in the hybrid mode can take place as follows. When the shift element K3 of the connecting clutch is disengaged, a change from the first electric-machine gear step E1 into the second electric-machine gear step E2 can take place in the background without load. As a result, the rotational speed of the first electric prime mover 16 is reduced. This shifting process takes place while the internal combustion engine 14 and/or the second electric prime mover 18 maintain(s) the tractive force in one of the gear steps 1, 3, 5 of the hybrid transmission 20.

[0069] In the hybrid mode, the first electric prime mover 16 can be decoupled when the internal combustion engine 14 utilizes one of the gear steps 1, 3, 5 of the hybrid transmission 20. In this way, an efficient internal combustion engine-driven operation is possible.

[0070] Preferably, the second electric prime mover 18 can be dimensioned smaller than the first electric prime mover 16, since the second electric prime mover does not need to perform essential driving functions. The first electric prime mover 16 is utilized as a main prime mover.

[0071] FIGS. 4 through 6 show further variants of hybrid transmissions 20 according to example aspects of the invention. Identical reference characters refer to identical features and are not explained once again. Only the differences are to be discussed in the following.

[0072] FIG. 4 shows a second example variant of a hybrid transmission 20. The first sub-transmission and the second sub-transmission are designed as a mirror image practically at a center of the hybrid transmission 20. The gear steps 1, 3, and 5, i.e., the odd gear steps of the hybrid transmission 20, are arranged on the first sub-transmission. The gear steps 2 and 4 are arranged on the second sub-transmission. The first and second electric prime movers 16, 18 are each connected to a sub-transmission, wherein the first electric prime mover 16, which is preferably utilized as a main prime mover, is operatively connected to the second sub-transmission, i.e., the transmission that includes the even gear steps. The first and second electric prime movers 16, 18 are connected axially in parallel and are each connected to the gearwheel of the highest gear step of the particular sub-transmission, wherein this gearwheel is designed as a fixed gear in each case. In the example shown in FIG. 4, the gear sequence from the left, i.e., as viewed from the connection point of the internal combustion engine 14, is: 5, 1, 3, 2, and 4.

[0073] In FIG. 5, a third example variant of a hybrid transmission 20 is shown, in which, in contrast to the example variant shown in FIG. 2, the internal combustion engine clutch K0 has been omitted. As a result, the hybrid transmission 20 can be designed having fewer components and, in particular, having fewer actuators. The open-loop control of the hybrid transmission 20 is simplified. It is understood that, in the case of this type of hybrid transmission 20, pulling away from rest preferably takes place by the first electric prime mover 16.

[0074] FIG. 6 shows one further fourth example variant of a hybrid transmission 20, in which the internal combustion engine clutch K0 is designed as a friction clutch. As a result, the internal combustion engine clutch K0 can also be disengaged under load. For example, during a full brake application or a malfunction of the internal combustion engine 14, the internal combustion engine clutch K0 can be disengaged immediately. In particular, the internal combustion engine clutch K0 can also be engaged at a differential speed. As a result, a “flywheel start” of the internal combustion engine 14 with the second electric prime mover 18 is possible, wherein an inertial mass or an inertia torque of the second electric prime mover 18 is preferably utilized for starting the internal combustion engine 14.

[0075] It is understood that the mirror imaging or the arrangement of the gear steps of the hybrid transmission 20 described with reference to FIG. 4 is also applicable for the example embodiments from FIGS. 5 and 6.

[0076] The invention was comprehensively described and explained with reference to the drawings and the description. The description and the explanation are to be understood as an example and are not to be understood as limiting. The invention is not limited to the disclosed embodiments. Other embodiments or variations result for a person skilled in the art within the scope of the utilization of the present invention and within the scope of a precise analysis of the drawings, the disclosure, and the following claims.

[0077] In the claims, the words “comprise” and “comprising” do not rule out the presence of further elements or steps. The indefinite article “a” does not rule out the presence of a plurality. A single element or a single unit can carry out the functions of several of the units mentioned in the claims. The mere mention of a few measures in multiple various dependent claims is not to be understood to mean that a combination of these measures cannot also be advantageously utilized.

[0078] Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.

REFERENCE CHARACTERS

[0079] 10 motor vehicle [0080] 12 motor vehicle drive train [0081] 14 internal combustion engine [0082] 16 first electric prime mover [0083] 18 second electric prime mover [0084] 20 hybrid transmission [0085] 22 energy accumulator [0086] 24 first transmission input shaft [0087] 26 second transmission input shaft [0088] 28 countershaft [0089] 30 fixed gear [0090] 32 fixed gear [0091] 34 drive output [0092] 36 gear shift matrix [0093] K0 internal combustion engine clutch [0094] K3 shift element [0095] A shift element [0096] B shift element [0097] C shift element [0098] D shift element [0099] E shift element [0100] A1-A5 transmission axes