Hybrid Transmission for a Motor Vehicle Powertrain, Motor Vehicle Powertrain, and Motor Vehicle Comprising Same

Abstract

A hybrid transmission of a countershaft design for a motor vehicle powertrain having an internal combustion engine, a first electric prime mover, and a second electric prime mover has a transmission drive shaft drivingly connected to the second electric prime mover, a first sub-transmission having a first transmission input shaft, and a second sub-transmission having a second transmission input shaft, the second transmission input shaft being drivingly connected to the first electric prime mover. The transmission further has a first coupling element, the transmission drive shaft being connectable to the internal combustion engine via the first coupling element. Moreover, the transmission has a second coupling element, the first transmission input shaft being connectable to the second transmission input shaft via the second coupling element. Additionally, the transmission has a third coupling element, the transmission drive shaft being connectable to the first transmission input shaft via the third coupling element.

Claims

1-12. (canceled)

13. A hybrid transmission (10) of a countershaft design for a motor vehicle powertrain (12) having an internal combustion engine (14), a first electric prime mover (16), and a second electric prime mover (18), the hybrid transmission (10) comprising: a transmission drive shaft (38) drivingly connected to the second electric prime mover (18); a first sub-transmission (20) having a first transmission input shaft (40); a second sub-transmission (22) having a second transmission input shaft (42), the second transmission input shaft (42) being drivingly connected to the first electric prime mover (16); a first coupling element (K0), the transmission drive shaft (38) being connectable to the internal combustion engine (14) via the first coupling element (K0); a second coupling element (K1), the first transmission input shaft (40) being connectable to the second transmission input shaft (42) via the second coupling element (K1); and a third coupling element (K2), the transmission drive shaft (38) being connectable to the first transmission input shaft (40) via the third coupling element (K2).

14. The hybrid transmission (10) of claim 13, further comprising: multiple shift elements (A, B, C, D, E) for engaging a total of five gear steps (1, 2, 3, 4, 5); and multiple gearwheel pairs for forming multiple gear steps, each of the gearwheel pairs including a respective idler gear and a respective fixed gear arranged in a respective gear set plane, wherein one of the multiple gear steps is arranged at one of the first and second sub-transmissions and adjacent gear steps of the multiple gear steps to the one of the multiple gear steps are in another of the first and second sub-transmissions.

15. The hybrid transmission (10) of claim 14, wherein the first sub-transmission (20) is drivingly connected to the first electric prime mover (16) at the fixed gear of a gearwheel pair of the multiple gearwheel pairs that forms a highest gear step of the multiple gear steps in the first sub-transmission.

16. The hybrid transmission (10) of claim 14, wherein: the idler gear of each of one or both of a first gear step and a second gear step of the multiple gear steps includes a shared shift element with a further gear-forming gearwheel pair of the multiple gearwheel pairs, the multiple shift elements (A, B, C, D, E) are form-locking shift elements, and at least two of the multiple shift elements are double shift elements, each of the double shift elements being actuatable by a respective double-acting actuator.

17. The hybrid transmission (10) of claim 14, wherein: the first, second, and third coupling elements (K0, K1, K2) are friction-locking or form-locking coupling elements, and at least one of the first, second, and third coupling elements forms a double element with one of the multiple shift elements, each double element being actuatable by a respective double-acting actuator.

18. The hybrid transmission (10) of claim 13, wherein: the first transmission input shaft (40) and the second transmission input shaft (42) are coaxial, and one of the first and second transmission input shafts is a hollow shaft and at least partially encompasses another of the first and second transmission input shafts.

19. The hybrid transmission (10) of claim 13, wherein the first transmission input shaft (40) and the second transmission input shaft (38) are coaxial.

20. A motor vehicle powertrain (12), comprising: an internal combustion engine (14) for providing input power; a first electric prime mover (16) for providing input power; a second electric prime mover (18) for providing input power; and the hybrid transmission (10) of claim 13.

21. The motor vehicle powertrain (12) of claim 20, wherein the second electric prime mover (18) is an integrated starter generator for starting the internal combustion engine (14), and wherein the second electric prime mover (18) is operable as a charging generator for one or more of charging an energy accumulator, supplying a main power circuit, and supplying the first electric prime mover during a serial operation.

22. The motor vehicle powertrain (12) of claim 20, 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 (40) and the second transmission input shaft (42).

23. The motor vehicle powertrain (12) of claim 20, wherein: one or both of the second electric prime mover (18) and the internal combustion engine (14) at least partially provides supporting force during gear changes of the first electric prime mover (16); and the first electric prime mover (16) at least partially provides supporting force during gear changes of one or both of the second electric prime mover and the internal combustion engine.

24. A motor vehicle (25), comprising the motor vehicle powertrain (12) of claim 20, the motor vehicle (25) further comprising: an energy accumulator (70) for storing energy for supplying the first electric prime mover (16), the second electric prime mover (18), and a vehicle electronics system (72); and a main power circuit (74) for transmitting the energy between the energy accumulator and one or both of the first electric prime mover and the second electric prime mover.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The invention is 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:

[0031] FIG. 1 shows a schematic view of a motor vehicle drive train according to the invention;

[0032] FIG. 2 shows a schematic view of a motor vehicle with a motor vehicle drive train according to the invention;

[0033] FIG. 3 shows a schematic view of a hybrid transmission according to the invention in a motor vehicle drive train;

[0034] FIG. 4 shows a schematic view of a gear shift matrix of the hybrid transmission according to the invention from FIG. 3; and

[0035] FIG. 5 shows a schematic view of an embodiment of a hybrid transmission according to the invention.

DETAILED DESCRIPTION

[0036] 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.

[0037] FIG. 1 diagrammatically shows an embodiment of a hybrid transmission 10 in 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. The hybrid transmission 10 includes a first sub-transmission 20, a second sub-transmission 22, and a drive output arranged at a countershaft 24. The first electric prime mover 16 is operatively connected to the second sub-transmission 22. The internal combustion engine 14 is operatively connected to the second electric prime mover 18 by a first coupling element K0. By a second coupling element K1, the first sub-transmission 20 is operatively connected to the second sub-transmission 22. By a third coupling element K2, the second electric machine 18 is operatively connected to the first sub-transmission 20. Therefore, if the first and third coupling elements K0 and K2 are engaged, the internal combustion engine 14 is also operatively connected to the first sub-transmission 20. Moreover, by additionally engaging the second coupling element K1, the second sub-transmission 22 is utilized for the internal combustion engine 14 and/or the second electric prime mover 18.

[0038] With this arrangement of the coupling elements K0, K1, K2, each gear step, regardless of which sub-transmission it is located on, is engaged for each of the prime movers 14, 16, 18. In particular, the first electric prime mover 16 utilizes the first gear, i.e., the lowest gear stage, of the first sub-transmission 20. It is possible to implement a serial operation. For this purpose, the third coupling element K2 is disengaged and the first coupling element K0 is engaged. The internal combustion engine 14 then drives the second electric prime mover 18 as a generator and, in this way, provides energy, which is delivered to the first electric prime mover 16.

[0039] In a hybrid operation, i.e., when the internal combustion engine 14 and at least one of the electric prime movers 16, 18 are utilized for driving a motor vehicle, the second electric prime mover 18 assists the internal combustion engine 14 during a synchronization, for example, in order to shift the individual gear steps. In this example, the first electric prime mover 16 is a main prime mover and preferably utilizes the second gear, which is located in the second sub-transmission 22. In particular driving situations such as, for example, in the presence of high driving resistance, the first electric prime mover 16 also utilizes the first gear, which is arranged in the first sub-transmission 20. For this purpose, the two sub-transmissions must be connected by the second coupling element K1.

[0040] FIG. 2 diagrammatically shows a motor vehicle 25 with an above-described motor vehicle drive train 12 and an above-described hybrid transmission 10. The drive output arranged at the countershaft 24 transmits the input power to a differential 26. The differential 26 distributes the input power via an output shaft 28 to the driven wheels 30 of the motor vehicle 25. In this example, only one axle of the motor vehicle 25 is driven. It is understood that an all-wheel drive is also implemented, in that, for example, the drive output arranged at the countershaft 24 drives a further differential, in order to drive a further input shaft and, thereby, further wheels 30. The motor vehicle 25 includes, furthermore, an energy accumulator 70 for supplying the first electric prime mover 16, the second electric prime mover 18, and a vehicle electronics system 72. The energy accumulator 70 is, for example, in the form of a battery or a capacitor. A main power circuit 74 is provided for transmitting the energy between the energy accumulator 70 and the first electric prime mover 16 and/or the second electric prime mover 18.

[0041] FIG. 3 diagrammatically shows an embodiment of a hybrid transmission 10 in a motor vehicle drive train 12. Identical reference characters refer to identical features. The first electric prime mover 16 includes a fixed gear 32 at an output shaft and is connected to the second sub-transmission 22 by the fixed gear 32. The second electric prime mover 18 includes a fixed gear 34 at an output shaft. The fixed gear 34 is in engagement with a fixed input gear 36, which is located at a transmission drive shaft 38. The transmission drive shaft 38 is operatively connected to a first transmission input shaft 40 of the first sub-transmission 20 by the third coupling element K2.

[0042] The first transmission input shaft 40 of the first sub-transmission 20 is operatively connected to a second transmission input shaft 42 of the second sub-transmission 22 by the second coupling element K1. The first transmission input shaft 40 is a solid shaft. The second transmission input shaft 42 is a hollow shaft and encompasses the first transmission input shaft 40, at least in sections.

[0043] The first sub-transmission 20 includes a first gear step 1, a third gear step 3, and a fifth gear step 5. The first gear step 1 is formed by a gearwheel pair, which includes a fixed gear 44 at the first transmission input shaft 40 and an idler gear 46 at the countershaft 24. The idler gear 46 is operatively connected or “connectable” to the countershaft 24 by a first shift element A.

[0044] The second sub-transmission 22 includes a second gear step 2 and a fourth gear step 4. The second gear step 2 is formed by a fixed gear 48 at the second transmission input shaft 42 and an idler gear 50 at the countershaft 24. The idler gear 50 is operatively connected or “connectable” to the countershaft 24 by a second shift element B.

[0045] The third gear step 3 is formed by a fixed gear 52 at the countershaft 24 and an idler gear 54 at the first transmission input shaft 40. The idler gear 54 is operatively connected or “connectable” to the first transmission input shaft 40 by a third shift element C.

[0046] The fourth gear step 4 is formed by a fixed gear 56 at the second transmission input shaft 42 and an idler gear 58 at the countershaft 24. The idler gear 58 is operatively connected or “connectable” to the countershaft 24 by a fourth shift element D.

[0047] The fifth gear step 5 is formed by a fixed gear 60 at the first transmission input shaft 40 and an idler gear 62 at the countershaft 24. The idler gear 62 is operatively connected or “connectable” to the countershaft 24 by a fifth shift element E.

[0048] The countershaft 24 includes, furthermore, a drive output, which includes a first output gearwheel 64 and a second output gearwheel 66 in engagement with the first output gearwheel 64. The second output gearwheel 66 is operatively connected or “connectable” to the differential 26, wherein the differential 26 distributes the input power via the output shaft 28.

[0049] The second electric prime mover 18 is coupled to the internal combustion engine 14 by the first coupling element K0 and to the first transmission input shaft 40 by the third coupling element K2. In the axially parallel arrangement shown here, the second electric prime mover 18 is connected to the transmission drive shaft 38 either by one or multiple spur gear(s), or by a traction mechanism such as, for example, a chain or a belt.

[0050] In particular driving situations such as, for example, in the presence of high driving resistance, the first electric prime mover 16 utilized as a main prime mover uses the shortest or lowest gear to drive the motor vehicle. The first shift element A, the first coupling element K0, and the second coupling element K1 are engaged. The first electric prime mover 16 therefore utilizes the first gear and, thereby, the lowest ratio. In this case, the motor vehicle is in a serial operation. The second electric prime mover 18 operates as a generator and is operatively connected to the internal combustion engine 14 by the engaged first coupling element K0. In this case, the third coupling element K2 is disengaged, in order to decouple the second electric prime mover 18 from the hybrid transmission 10, allowing the second electric prime mover 18 to be effectively operated as a generator.

[0051] A transition out of the above-described serial operation into a hybrid operation is possible. For this purpose, the third coupling element K2 is engaged. Thereafter, the internal combustion engine 14, together with the second electric prime mover 18, supports the tractive force, allowing the second coupling element K1 to be disengaged. In this case, the first electric prime mover 16 is load-free and synchronizes the second shift element B. The second shift element B is engaged, and so the second gear, i.e., the second-lowest gear stage, is engaged for the first electric prime mover 16.

[0052] Thereafter, the first electric prime mover 16 supports the tractive force and the internal combustion engine 14, together with the second electric prime mover 18, switches into a no-load condition. For example, a shift into the second gear step takes place by disengaging the first shift element A and engaging the second coupling element K1. The third coupling element K2 preferably remains engaged during this process.

[0053] FIG. 4 shows a gear shift matrix 68 of the hybrid transmission 10 from FIG. 3 and the following embodiment of a hybrid transmission 10. A total of 13 shift conditions are represented. In the first column, internal-combustion-engine gear steps V1, V2, V3, V4, V5 of the internal combustion engine 14 as well as electric-machine gear steps E1.1, E1.2, E1.3 of the first electric prime mover 16 and electric-machine gear steps E2.1, E2.2, E2.3, E2.4, E2.5 of the second electric prime mover 18 are represented. The shift conditions of the coupling elements K0, K2, K1 are represented in the second through fourth columns. The shift conditions of the shift elements A, B, C, D, E are represented in the fifth through ninth columns. An “X” for a coupling element means that it is engaged, i.e., drivingly connects the two shafts to each other that are associated with the coupling element. An “X” for a shift element means that it is engaged, i.e., drivingly connects the idler gear associated therewith to the shaft associated therewith. Consequently, the gear stages 1, 2, 3, 4, 5 of the hybrid transmission 10 which correspond to the internal-combustion-engine gear steps V1, V2, V3, V4, V5, the electric-machine gear steps E1.1, E1.2, E1.3, E2.1, E2.2, E2.3, E2.4, E2.5 is apparent from the gear shift matrix 68.

[0054] In order to engage the internal-combustion-engine gear steps V1, V2, V3, V4, V5, therefore, the first and third coupling elements K0, K2 must always be engaged so that the internal combustion engine 14 is connected to the hybrid transmission 10. In order to engage a first internal-combustion-engine gear step V1, the first shift element A is also engaged. In order to engage a second internal-combustion-engine gear step V2, the first sub-transmission 20 and the second sub-transmission 22 must be drivingly connected to each other, i.e., the second coupling element K1 must also be engaged and the second shift element B is also engaged. In order to engage a third internal-combustion-engine gear step V3, the third shift element C is also engaged. In order to engage a fourth internal-combustion-engine gear step V4, the second coupling element K1 and the fourth shift element D are also engaged. The fifth shift element E is additionally engaged for the fifth internal-combustion-engine gear step V5. Provided that the coupling elements and/or shift elements are not designated as engaged, it is to be assumed that they are in the disengaged condition.

[0055] The first and third coupling elements K0, K2 are disengaged for the electric-machine gear steps E1.1, E1.2, E1.3 of the first electric prime mover 16. The second coupling element K1 and the first shift element A are engaged for a first electric-machine gear step E1.1 of the first electric prime mover 16. The second shift element B is engaged for a second electric-machine gear step E1.2 of the first electric prime mover 16. The fourth shift element D is engaged for a third electric-machine gear step E1.3 of the first electric prime mover 16.

[0056] The third coupling element K2 is engaged for the electric-machine gear steps E2.1, E2.2, E2.3, E2.4, E2.5 of the second electric prime mover 18. The first shift element A is to be additionally engaged for a first electric-machine gear step E2.1 of the second electric prime mover 18. The second coupling element K1 and the second shift element B are to be engaged for a second electric-machine gear step E2.2 of the second electric prime mover 18. The third shift element C is to be engaged for a third electric-machine gear step E2.3 of the second electric prime mover 18. The fourth shift element D and the second coupling element K1 are to be engaged for a fourth electric-machine gear step E2.4 of the second electric prime mover 18. The fifth shift element E is to be engaged for a fifth electric-machine gear step E2.5 of the second electric prime mover 18.

[0057] In a hybrid operation, the internal-combustion-engine gear steps V1, V2, V3, V4, V5 are combined with the electric gear steps E1.1, E1.2, E1.3. Moreover, it is also conceivable to also utilize the electric gear steps E2.1, E2.2, E2.3, E2.4, E2.5, which are engaged similarly to the combustion gear steps V1, V2, V3, V4, in a hybrid mode.

[0058] A further variant of a hybrid transmission 10 is diagrammatically shown in FIG. 5. Identical reference characters refer to identical features. The differences are to be discussed in the present case. The second electric prime mover 18 is a coaxial machine in this case, wherein a stator of the second electric prime mover 18 is rotationally fixed to a transmission housing or the like. A rotor of the second electric prime mover 18 forms the transmission drive shaft 38. It is understood that a reduction gear, for example, in the form of a planetary gear set, is provided in order to step up or step down the input power between the rotor and the transmission drive shaft 38.

[0059] Furthermore, it is understood that the arrangement of the fixed gears and the idler gears, including the shift elements, is interchanged in the embodiments shown. It is provided, for example, that no shift elements and no idler gears are provided at the countershaft 24. Moreover, the order of the individual gear steps is interchangeable, wherein, preferably, a high gear step is arranged at an end or a beginning of a transmission in order to connect an electric prime mover by a fixed gear having a high gear step to a sub-transmission and, thereby, have axial installation space available in order to be able to utilize an axially long electric prime mover.

[0060] It is understood, furthermore, that the first electric prime mover can also be a coaxial machine, wherein the rotor is part of the second transmission input shaft 42. It is also conceivable that a reduction gear, for example, in the form of a planetary gear set, is provided between the rotor of the coaxial machine and the second transmission input shaft 42.

[0061] 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.

[0062] 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 carries 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.

[0063] 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

[0064] 10 hybrid transmission [0065] 12 motor vehicle drive train [0066] 14 internal combustion engine [0067] 16 first electric prime mover [0068] 18 second electric prime mover [0069] 20 first sub-transmission [0070] 22 second sub-transmission [0071] 24 countershaft [0072] 25 motor vehicle [0073] 26 differential [0074] 28 output shaft [0075] 30 wheel [0076] 32 fixed gear of the first electric prime mover [0077] 34 fixed gear of the second electric prime mover [0078] 36 fixed input gear [0079] 38 transmission drive shaft [0080] 40 first transmission input shaft [0081] 42 second transmission input shaft [0082] 44 fixed gear of the first gear step [0083] 46 idler gear of the first gear step [0084] 48 fixed gear of the second gear step [0085] 50 idler gear of the second gear step [0086] 52 fixed gear of the third gear step [0087] 54 idler gear of the third gear step [0088] 56 fixed gear of the fourth gear step [0089] 58 idler gear of the fourth gear step [0090] 60 fixed gear of the fifth gear step [0091] 62 idler gear of the fifth gear step [0092] 64 first output gearwheel [0093] 66 second output gearwheel [0094] 68 gear shift matrix [0095] 70 energy accumulator [0096] 72 vehicle electronics system [0097] 74 main power circuit