Hybrid Transmission Assembly for a Motor Vehicle Powertrain, and Method for Operating a Hybrid Powertrain

Abstract

A hybrid transmission arrangement (16) for a motor vehicle drive train (10) includes a first sub-transmission (32) with a first input shaft (24), a second sub-transmission (34) with a second input shaft (26), a first electric machine (56) connectable to the first input shaft (24) via a second clutch (K2), and a second electric machine (60) connected to the second input shaft (26). The first electric machine (56) is connected via a first gearwheel (70) to an intermediate element (74), which forms an input element of the second clutch (K2). The second electric machine (60) is connected to the second input shaft (26) via a second gearwheel (72). The first gearwheel (70) and the second gearwheel (72) are arranged coaxially and adjacent to each other.

Claims

1-14: (canceled)

15. A hybrid transmission arrangement (16) for a motor vehicle drive train (10), comprising: a first sub-transmission (32) with a first input shaft (24); a second sub-transmission (34) with a second input shaft (26); a first electric machine (56) connectable to the first input shaft (24) via a second clutch (K2); and a second electric machine (60) connected to the second input shaft (26), wherein the first electric machine (56) is connected via a first gearwheel (70) to an intermediate element (74), and the intermediate element (74) forms an input element of the second clutch (K2), wherein the second electric machine (60) is connected to the second input shaft (26) via a second gearwheel (72), and wherein the first gearwheel (70) is arranged coaxially and adjacent to the second gearwheel (72).

16. The hybrid transmission arrangement of claim 15, wherein the intermediate element (74) is connectable or connected via a first clutch (K1) to a transmission arrangement input shaft (76).

17. The hybrid transmission arrangement of claim 16, wherein one or both of the first gearwheel (70) and the intermediate element (74) is arranged axially between the second clutch (K2) and the first clutch (K1).

18. The hybrid transmission arrangement of claim 15, wherein the first input shaft (24) and the second input shaft (26) are connectable via a third clutch (K3).

19. The hybrid transmission arrangement of claim 18, wherein the third clutch (K3) and a gearshift clutch (C) for engaging a gear set (38) of a sub-transmission (32) form a gearshift clutch assembly (66).

20. The hybrid transmission arrangement of claim 15, wherein: the first electric machine (56) is connected to the first gearwheel (70) via at least one first intermediate gearwheel (59); or the second electric machine (60) is connected to the second gearwheel (72) via at least one second intermediate gearwheel (63); or both the first electric machine (56) is connected to the first gearwheel (70) via the at least one first intermediate gearwheel (59) and the second electric machine (60) is connected to the second gearwheel (72) via the at least one second intermediate gearwheel (63).

21. The hybrid transmission arrangement of claim 15, wherein one or more of the first clutch (K1), the second clutch (K2), a third clutch (K3), and at least one gearshift clutch (A, B, C, D, E) of the transmission arrangement (16) is a dog clutch.

22. The hybrid transmission arrangement of claim 15, wherein the second gearwheel (72) is part of a gear-step gear set (50) of the second sub-transmission (34).

23. The hybrid transmission arrangement of claim 22, wherein the gear-step gear set (50) of the second sub-transmission (34) is associated with a highest gear step (4) of the second sub-transmission (34).

24. The hybrid transmission arrangement of claim 15, wherein the second electric machine (60) has a higher power than the first electric machine (56).

25. The hybrid transmission arrangement of claim 15, wherein an input shaft arrangement (27) formed by the first input shaft (24) and the second input shaft (26) is arranged at a center of four quadrants (I-IV) in an axial plane, a first quadrant (I) of the four quadrants (I-IV) is situated above the input shaft arrangement (27) and on a first longitudinal side of the input shaft arrangement (27), a second quadrant (II) of the four quadrants (I-IV) is situated below the input shaft arrangement (27) and on the first longitudinal side of the input shaft arrangement (27), a third quadrant (III) of the four quadrants (I-IV) is situated below the input shaft arrangement (27) and on a second longitudinal side of the input shaft arrangement (27), and a fourth quadrant (IV) of the four quadrants (I-IV) is situated above the input shaft arrangement (27) and on the second longitudinal side of the input shaft arrangement (27), and wherein, one or more of: an axis (A4) of one of the first and second electric machines (56, 60) is situated in the first quadrant (I), and an axis (A5) of the of the first and second electric machines (56, 60) is situated in the fourth quadrant (IV); an axis (A2) of a countershaft (28) is situated in the second quadrant (II); an axis (A3) of a power distribution unit is situated in the second quadrant (II); and a plurality of actuating units (S1-S5) for actuating one or more of the first clutch, the second clutch, a third clutch, a gearshift clutch (A, C, E) for engaging a gear-step gear set (36, 38, 42) of the first sub-transmission (32), and a gearshift clutch (D, B) for engaging a gear-step gear set (50, 52) of the second sub-transmission (34) is situated in the third quadrant (III).

26. A method for operating the hybrid transmission arrangement of one of claim 15, comprising, in an internal combustion engine-driven operation or a hybrid operation: utilizing gear steps (1, 3, 5) of the first sub-transmission (32) by engaging the first clutch (K1) and the second clutch (K2); and utilizing gear steps (2, 4) of the second sub-transmission (34) by engaging the first clutch (K1), the second clutch (K2), and the third clutch (K3).

27. A method for operating the hybrid transmission arrangement of claim 15, comprising, in an internal combustion engine-driven operation: disengaging the third clutch (K3) in a gear step of the first sub-transmission (32) in order to decouple the second sub-transmission (34) and the second electric machine (60) associated with the second sub-transmission (34).

28. A method for operating the hybrid transmission arrangement of claim 15, comprising, in a purely electric motor-driven operation: one or both of providing input power of the first electric machine (56) via the first sub-transmission (32) and providing input power of the second electric machine (60) via the second sub-transmission (34); and wherein, while a gear change is carried out in the second sub-transmission, the first clutch (K1) is disengaged, a powershift is implemented, or both the first clutch (K1) is disengaged and the powershift is implemented, and wherein one or both of the first electric machine (56) maintains tractive force via the first sub-transmission (32) and the second electric machine (60) maintains tractive force via the second sub-transmission (34) when the powershift is implemented.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Exemplary embodiments of the invention are represented in the drawings and are explained in greater detail in the following description, wherein

[0092] FIG. 1 shows a diagrammatic gear set representation of an example embodiment of a hybrid drive train with a hybrid transmission arrangement; and

[0093] FIG. 2 shows an axial view of a preferred example embodiment of a hybrid transmission arrangement with four quadrants represented.

DETAILED DESCRIPTION

[0094] 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.

[0095] In FIG. 1, a hybrid drive train for a motor vehicle, in particular a passenger car, is represented in diagrammatic form and is labeled, in general, with 10.

[0096] The hybrid drive train 10 includes an internal combustion engine 12, which is connected to an input element of a clutch assembly 14. The clutch assembly 14 is connected on the output side to a hybrid transmission arrangement 16. An output of the hybrid transmission arrangement 16 is connected to a power distribution unit 18, which can be designed, for example, as a mechanical differential and can distribute the input power to two driven wheels 20L, 20R of the motor vehicle.

[0097] Moreover, the hybrid drive train 10 includes a control device 22 for controlling all components thereof.

[0098] The clutch assembly 14 is arranged on an axis A1, which is coaxial to a crankshaft of the internal combustion engine 12. The clutch assembly 14 can include two friction clutches or one friction clutch and a non-synchronized dog clutch. In the present case, the clutch assembly 14 contains two non-synchronized dog clutches K1 and K2. The first clutch K1 has an input element, which is rotationally fixed to the crankshaft of the internal combustion engine 12. The first clutch K1 has a first output element. The second clutch K2 has an input element, which is rotationally fixed to the output element of the first clutch K1, and a second output element. The output elements are arranged coaxially to each other.

[0099] The transmission arrangement 16 includes a first input shaft 24 and a second input shaft 26. The input shafts 24, 26 are arranged coaxially to each other and to the axis A1. The first input shaft 24 is designed as an inner shaft. The second input shaft 26 is designed as a hollow shaft.

[0100] Moreover, the transmission arrangement 16 includes a countershaft 28, which is designed as an output shaft 28 and is arranged coaxially to a second axis A2. The output shaft 28 is connected via an output gear set 30 to the power distribution unit 18, which is arranged coaxially to an axis A3.

[0101] A parking interlock gear P can be rotationally fixed at the output shaft 28 or at an input element of the power distribution unit 18. The hybrid drive train 10 can be immobilized by the parking interlock gear P. The associated parking lock device is not represented, for the sake of clarity.

[0102] The transmission arrangement 16 has a first sub-transmission 32 and a second sub-transmission 34. The sub-transmissions 32, 34 are arranged axially offset with respect to each other. The first sub-transmission 32 is arranged adjacent to a first axial end of the transmission arrangement 16. The second sub-transmission 34 is arranged adjacent to a second axial end of the transmission arrangement 16, wherein the second axial end is adjacent to the clutch assembly 14. The sub-transmissions 32, 34 have a plurality of engageable gear sets, which, in the engaged condition, connect an input shaft and the output shaft 28 in each case.

[0103] The first sub-transmission 32 has a first gear set 36 for the first forward gear step 1 and a second gear set 38 for the third forward gear step 3. The second gear set 38 is arranged closer to the second axial end of the transmission arrangement 16 than the first gear set 36. Moreover, the first sub-transmission 32 has a third gear set 42 for the fifth forward gear step 5. The third gear set 42 is arranged closer to the first axial end of the transmission arrangement 16 than the first gear set 36. A first gearshift clutch assembly 40 is arranged between the first gear set 36 and the third gear set 42 and, in fact, coaxially to the axis A2. The first gearshift clutch assembly 40 includes a first gearshift clutch A for engaging the first gear set 36 and a second gearshift clutch E for engaging the third gear set 42. The two gearshift clutches A, E are alternately engageable and are designed as non-synchronized dog clutches. The engagement of a gear set includes the rotationally fixed connection of an idler gear of the particular gear set to an associated shaft. In the present case, for example, the first gear set 36 is engaged, in that an idler gear of the first gear set 36, which is rotatably mounted at the output shaft 28, is rotationally fixed to the output shaft 28, in order to bring the first gear set 36 into the power flow in this way.

[0104] The second gear set 38 is engageable by a gearshift clutch C and has an idler gear, which is rotatably mounted at the first input shaft 24.

[0105] The second sub-transmission 34 has a fourth gear set 48 for the second forward gear step 2 and a fifth gear set 50 for the fourth forward gear step 4. The fifth gear set 50 is arranged closer to the second axial end than the fourth gear set 48. A second gearshift clutch assembly 52 is arranged between the fourth and fifth gear sets 48, 50 and, in fact, coaxially to the axis A2. The second gearshift clutch assembly 52 has a gearshift clutch B for engaging the fourth gear set 48 and a gearshift clutch D for engaging the fifth gear set 50. The gearshift clutches B and D are accommodated in the second gearshift clutch assembly 52 in such a way that the gearshift clutches B, D are alternately actuatable.

[0106] Consequently, the transmission arrangement 16 has five gear set planes, namely, starting from the second axial end toward the first axial end, in the following order: gear set 50 for the fourth forward gear step 4; gear set 48 for the second forward gear step 2; gear set 38 for the third forward gear step 3; gear set 36 for the first forward gear step 1; and gear set 42 for the fifth forward gear step 5.

[0107] Moreover, the hybrid drive train 10 includes a first electric machine 56, which is arranged coaxially to a fourth axis A4. The first electric machine 56 has a first pinion 58, which is rotationally fixed to a rotor of the first electric machine 56 and is coaxial to the axis A4. The first pinion, which can also be referred to as a first machine pinion, is connected via a first intermediate gear 59 to a first gearwheel 70, which can also be referred to as a machine gearwheel. The first gearwheel 70 is rotationally fixed to an intermediate element in the form of an intermediate shaft 74, which is arranged coaxially to the first axis A1 and forms an output element of the first clutch K1 and an input element of the second clutch K2. The first gearwheel 70 is arranged in the axial direction between the first clutch K1 and the second clutch K2.

[0108] Moreover, the hybrid drive train 10 has a second electric machine 60, which is arranged axially parallel to the input shafts 24, 26 and, in fact, coaxially to a fifth axis A5. The second electric machine has a second pinion (second machine pinion) 62, which is arranged coaxially to the axis A5. The second pinion 62 is connected to the second input shaft 26 via a gear-step gear set of the second sub-transmission 34. In the present case, the second pinion 62 is connected to the fifth gear set 50 for the fourth forward gear step 4 via a second intermediate gear 63. More precisely, the second pinion 62 meshes with the second intermediate gear 63, which is rotatably mounted at an axle (not described in greater detail), and the second intermediate gear 63 meshes with a fixed gear of the fifth gear set 50, wherein the fixed gear is rotationally fixed to the second input shaft 26. The fixed gear of the fifth gear set 50 forms a second gearwheel 72.

[0109] The five axes A1, A2, A3, A4, A5 are all aligned in parallel with one another.

[0110] The clutch assembly 14 is arranged adjacent to the second axial end of the transmission arrangement 16, as mentioned above. An input element of the first clutch K1 is rigidly connected to a transmission arrangement input shaft 76, which, in the drive train 10, is rotationally fixed to a crankshaft of the prime mover 12.

[0111] The output gear set 30 is also arranged on the second axial side of the transmission arrangement 16 and is preferably axially aligned with the clutch assembly 14 or is situated approximately in a plane therewith. The parking interlock gear P can be fixed at the output shaft 28 between the output gear set 30 and the fifth gear set 50.

[0112] In the hybrid drive train 10, the second electric machine 60 is connected to a gear-step gear set of the associated sub-transmission, which is associated with the highest gear step of that sub-transmission. Moreover, the second electric machine 60 is connected via a gear-step gear set to the associated sub-transmission, which is preferably arranged adjacent to an axial end of the transmission arrangement.

[0113] The electric machines 56, 60 are arranged in axial overlap with each other. Due to the connection via intermediate gears 59, 63, high ratios for the particular gearwheels 70, 72 can be established, and so relatively high-speed electric machines can be utilized, which are compact.

[0114] The hybrid transmission arrangement in the present example embodiment has precisely five forward gear steps and does not have a reverse gear step. An operation in reverse can be exclusively established by the hybrid drive train 10 when one of the electric machines 56 or 60 is driven in the opposite direction of rotation.

[0115] The transmission arrangement 16 has no winding-path gear steps. Each gear set 36 through 50 includes precisely one idler gear and one fixed gear, wherein the idler gears of the gear sets 36, 38, 48, 50 are rotatably mounted at the output shaft 28, and wherein the idler gear of the gear set 42 is rotatably mounted at the first input shaft 24.

[0116] Moreover, the hybrid drive train 10 includes a third clutch K3, which can also be referred to as a bridge clutch.

[0117] The third clutch K3 is utilized for connecting the first input shaft 24 and the second input shaft 26. The third clutch K3 is arranged adjacent to the fourth gear set 48 for the second forward gear step 2 and is accommodated, with the gearshift clutch C for the second gear set 38 for engaging the third forward gear step 3, in a third gearshift clutch assembly 66. The third clutch K3, just like the gearshift clutches A, B, C, D, E, is implemented as a non-synchronized dog clutch.

[0118] The third gearshift clutch assembly 66 is arranged coaxially to the first axis A1 and, in fact, axially between the gear sets 38, 48.

[0119] The clutch assembly 14 with the first clutch K1 and the second clutch K2, and the three gearshift clutch assemblies 40, 52, 66 are actuatable by five actuating units S1 through S5.

[0120] One actuating unit S1 is utilized for actuating the second clutch K2, and can either engage or disengage the clutch K2. One actuating unit S5 is utilized independently thereof for actuating the first clutch K1 and can either engage or disengage the first clutch K1.

[0121] Moreover, the first gearshift clutch assembly 40 can be actuated by a fourth actuating unit S4. By the fourth actuating unit S4, either the gearshift clutch A can be engaged, or the gearshift clutch C can be engaged, or a neutral position can be established.

[0122] In a corresponding way, the second gearshift clutch assembly 52 can be actuated by a third actuating unit S3, in order to either engage the clutch D, or engage the clutch B, or establish a neutral position.

[0123] Finally, the third gearshift clutch assembly 66 can be engaged by a second actuating unit S2, in order to either engage the clutch K3, or engage the clutch C, or establish a neutral position.

[0124] With the transmission arrangement 16 from FIG. 1, it is possible to interchange the gear sets for the third and fifth forward gear steps 3 and 5 in the first sub-transmission 32.

[0125] Moreover, the second electric machine 60 does not necessarily need to be connected via a gear-step gear set to the associated input shaft 24, 26. Rather, it is also possible to fix a second gearwheel at the second output shaft 26, which is not associated with any gear step and is in engagement with the second pinion 62 directly or via a second intermediate gear.

[0126] In the following, different operations are explained, which are establishable with the hybrid drive train 10 from FIG. 1.

[0127] In all forward gear steps V1 through V5 establishable in a purely internal combustion engine-driven operation or in a hybrid operation, the first clutch K1 is continuously engaged and the second clutch K2 is also engaged. In the forward gear step V1, the gearshift clutch A is engaged and all other gearshift clutches B through E are disengaged. The third clutch K3 is also disengaged. Consequently, power flows from the internal combustion engine via the first clutch K1 and the second clutch K2 and the first input shaft 24 to the first gear set 36 and, from there, via the gearshift clutch A to the output shaft 28.

[0128] It is understood that pulling away from rest generally takes place purely via electric motors 56, 60 until a speed is reached, at which the internal combustion engine can be connected, i.e., at a speed that corresponds to a rotational speed above the idling speed of the internal combustion engine 12. Consequently, pulling away from rest takes place, for example, via the first electric machine 56 and with the first clutch K1 disengaged and the second clutch K2 engaged, and via the first gear set 36 for the forward gear step V1. As soon as a speed has been reached that corresponds to the speed of the internal combustion engine 12, the clutch K1 can be engaged. The clutch K1 remains engaged during the entire internal combustion engine-driven operation. Alternatively, it is possible to keep the clutch K1 engaged and to disengage the clutch K2. In this case, pulling away from rest can take place via the second electric machine 60, for example, with the gearshift clutch B for the forward gear step 2 engaged. The internal combustion engine 12 can then be started by the first electric machine 56.

[0129] During the changeover from the forward gear step V1 into the forward gear step V2, initially the gearshift clutch B for the forward gear step 2 is preliminarily engaged. This can take place, if necessary, with the aid of a synchronization by the second electric machine 60.

[0130] Thereafter, the gearshift clutch A for the forward gear step V1 is disengaged, wherein the tractive force is supported by the second electric machine 60 and the already engaged gear set 48 for the forward gear step V2. Thereafter, the third clutch K3 can be engaged, wherein the synchronization necessary therefor takes place, on the one hand, by a rotational-speed adaptation of the internal combustion engine 12, but also by appropriate synchronization measures of the first electric machine and/or the second electric machine 60. In the second forward gear step, power flows, consequently, from the internal combustion engine 12 via the first clutch K1, the second clutch K2, the first input shaft 24, the engaged third clutch K3, the second input shaft 26, and the gear set 48 for the second forward gear step, which is engaged by the gearshift clutch B, to the output shaft 28.

[0131] During the changeover into the forward gear step V3, the third clutch K3 is disengaged, the tractive force is supported via the second electric machine 60 and, thereafter, the connecting gear step 3 can be engaged in the first sub-transmission 32 by engaging the gearshift clutch C. The necessary synchronization can take place via the first electric machine 56.

[0132] Thereafter, the load can be supported by the first electric machine 56 and the gearshift clutch B of the forward gear step 2 can be disengaged.

[0133] The further gear changes from the gear steps V3 and V4 and from V4 and V5 result in a corresponding way. In both of the even forward gear steps V2 and V4, the third gearshift clutch K3 is engaged. The first clutch K1 and the second clutch K2 are always engaged.

[0134] Moreover, a purely electric motor-driven operation is possible with the first electric machine 56. In a first electric gear step E1.1, the gearshift clutch A for the forward gear step 1 is engaged. The first clutch K1 is disengaged. The second clutch K2 is engaged. In a second electric forward gear step E1.2, the gearshift clutch C, rather than the gearshift clutch A, is engaged. In a third electric-motor gear step E1.3, the gearshift clutch E is engaged.

[0135] Moreover, a purely electric motor-driven operation is possible with the second electric machine 60. In a first gear step E2.1, only the gearshift clutch B is engaged, and the third clutch K3 is disengaged. The second clutch K2 and/or the first clutch K1 are/is disengaged. In a second electric gear step E2.2, the gearshift clutch D, rather than the gearshift clutch B, is engaged.

[0136] In the purely electric operation, purely electric powershifts (i.e., gear changes between forward gear steps without or with reduced interruption of tractive force) are possible. Here, an electric motor-driven operation is established exclusively, for example, between the gear steps E1.1, E1.2, E1.3 or exclusively between the gear steps E2.1 and E2.2, and a gear change takes place while the other electric machine maintains the tractive force.

[0137] During a gear change, for example, from the forward gear step E1.1 into the forward gear step E1.2, the gearshift clutch B can be engaged in the second sub-transmission and, consequently, the second electric machine can maintain the tractive force during the gear change in the first sub-transmission 32.

[0138] In the purely internal combustion engine-driven operation or hybrid operation (i.e., for the case in which internal combustion engine-generated power and, optionally, electric motor-generated power are guided to the output shaft), it is advantageous that the third clutch K3 is utilized for connecting the second input shaft 26 to the first input shaft 24 and, consequently, always supplying internal combustion engine-generated power into the transmission arrangement 16 via the first input shaft 24. Consequently, the first electric machine 56 associated with the first sub-transmission 32 is always rotationally fixed to the internal combustion engine during this operation. As a result, it is possible to establish load-point displacements at the internal combustion engine 12 and the first electric machine 56 can provide assistance during the closed-loop control of the rotational speed when a synchronization process is to take place. In other words, since the first clutch K1 and the second clutch K2 always remain engaged, the first electric machine 56 can assist the internal combustion engine 12 during synchronization.

[0139] In order to integrate the third clutch K3, which is necessary therefor, into the transmission arrangement as efficiently as possible, the third clutch K3 is accommodated in the third gearshift clutch assembly 66. Since the third clutch K3 is therefore integrated with a gearshift clutch into a gearshift clutch assembly that is associated with that sub-transmission, the associated clutch K2 of which is always engaged in the internal combustion engine-driven or hybrid operation, the internal combustion engine 12 can utilize all gear steps of the transmission.

[0140] The second clutch K2 is disengaged, however, when a serial operation is established. Here, the first clutch K1 is engaged. Via the first sub-transmission 34 and the second electric machine 60, a purely electric motor-driven operation is established in a gear step, for example, in the forward gear step 2. The internal combustion engine 12 drives the first electric machine 56 via the engaged first clutch K1 and operates the first electric machine 56 as a generator, and so the power withdrawn from a vehicle battery by the second electric machine 60 in this purely electric operation can be simultaneously resupplied, at least partially, via the first electric machine 56.

[0141] The serial operation is utilized, in particular, in a crawling mode, in which the vehicle speed is lower than a minimum speed that is establishable by the internal combustion engine 12.

[0142] The sub-transmission 32 that is associated with the clutch K2, which is always engaged in the internal combustion engine-driven mode, preferably also includes the highest forward gear step of the transmission arrangement 16. As a result, when the third clutch is disengaged, the second electric machine 60 can be practically decoupled, in order to avoid drag losses. In addition, the first electric machine 56 can remain coupled, in order to supply the main power circuit with electrical energy (operation as a generator), or in order to establish a boost operation (operation as a motor).

[0143] During a gear shift from a forward gear step of the first sub-transmission 32 into a forward gear step of the second sub-transmission 34, the desired gear step is initially engaged in the second sub-transmission 34 by engaging the associated gearshift clutch (D or B). This takes place with the aid of a synchronization by the second electric machine 60, wherein the second electric machine 60 switches over, in a load-free manner, into the target gear step in the second sub-transmission 34. Thereafter, the second electric machine 60 supports the tractive force during the gear shift via the already engaged target gear step. During the gear shift, initially the gearshift clutch of the first sub-transmission 32, which is associated with the starting or source gear step, disengages and, thereafter, the third clutch K3 is engaged, wherein the internal combustion engine 12 and the first electric machine 56 interact during the synchronization.

[0144] During a gear shift from the second sub-transmission 34 into a gear step of the first sub-transmission 32, the second electric machine 60 initially supports the tractive force in the source gear step or the actual gear during the gear shift. During the gear shift, the third clutch K3 is initially disengaged and one of the shift elements A, C, E engages, wherein the internal combustion engine 12 and the first electric machine 56 interact during the necessary synchronization. After the disengagement of the third clutch K3 and the load transfer on the first sub-transmission 32, the output gear step (actual gear step) in the second sub-transmission 34 is disengaged.

[0145] It is understood that a stationary charging can also take place with the hybrid drive train when the vehicle is at a standstill. For example, the first clutch K1 can be engaged and input power of the internal combustion engine 12 is supplied via the intermediate shaft 74 into the first electric machine 56. The second clutch K2 remains disengaged. In this condition, a start of the internal combustion engine 12 can also take place by the first electric machine 56.

[0146] In general, it is also conceivable to engage both clutches K1 and K2, in order to allow a charging process to take place by the first electric machine 56 and also by the second electric machine 60. In this case, the internal combustion engine 12 drives both electric machines 56, 60, and both electric machines 56, 60 operate as generators, in order to charge a vehicle battery. All gearshift clutches A through E are disengaged in this case.

[0147] In FIG. 2, an axial view of a drive train 10 is represented, which can generally correspond to the drive train 10 from FIG. 1 with respect to configuration and mode of operation.

[0148] It is apparent that the axis A1 of the input shafts 24, 26 is situated in the center of a coordinate system having four quadrants I, II, III, and IV.

[0149] Since the drive train 10 is generally installed transversely in the direction of travel of a motor vehicle, a preferred forward direction of travel F is also represented in FIG. 2.

[0150] Of the four quadrants I-IV, a first quadrant I is situated above the input shaft arrangement 24, 26 and on a first longitudinal side (at the rear) of the input shaft arrangement 24, 26. A second quadrant II is situated underneath the input shaft arrangement and on the first longitudinal side. A third quadrant III is situated underneath the input shaft arrangement 24, 26 and is situated on a second longitudinal side (at the front) of the input shaft arrangement 24, 26. A fourth quadrant IV is situated above the input shaft arrangement and on the second longitudinal side of the input shaft arrangement.

[0151] The axis A2 of the countershaft 28 is situated in the second quadrant II. The axis A3 of the power distribution unit 18 is also situated in the second quadrant II. The axis A2 is arranged closer to the third quadrant III than the axis A3.

[0152] Actuating units S1-S5 are arranged in the third quadrant III.

[0153] The first electric machine 56 is completely arranged, with the axis A4, in the first quadrant I. The second electric machine 60 is completely arranged, with the axis A5, in the fourth quadrant IV.

[0154] The intermediate gear 59 is arranged completely in the first quadrant I. The intermediate gear 63 is arranged completely in the fourth quadrant IV.

[0155] The power distribution unit 18 is arranged predominantly in the second quadrant II, although the power distribution unit 18 can also extend into the first quadrant I.

[0156] The countershaft 28 with the gearwheels arranged thereon is arranged predominantly in the second quadrant II, although the countershaft 28 can also extend, with a few gearwheels, into the third quadrant III.

[0157] The longitudinal axis of the motor vehicle is then preferably aligned in parallel to the axis of the above-described coordinate system that separates the quadrants I, IV situated at the top from the quadrants II, III situated at the bottom.

[0158] The axis A3 is preferably situated coaxially to the driven wheels.

[0159] The drive train 10 can be arranged in the area of the front of the motor vehicle. Alternatively, however, the drive train 10 can also be arranged in the area of a rear of the motor vehicle. The longitudinal axis of the drive train 10 is aligned with the preferred forward direction of travel F. In any case, the drive train is installed in the transverse direction in the motor vehicle.

[0160] 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

[0161] 10 motor vehicle drive train [0162] 12 internal combustion engine [0163] 14 clutch assembly (K1/K2) [0164] 16 hybrid transmission arrangement [0165] 18 power distribution unit [0166] 20 driven wheels [0167] 22 control device [0168] 24 first input shaft [0169] 26 second input shaft [0170] 27 input shaft arrangement [0171] 28 output shaft [0172] 30 output gear set [0173] 32 first sub-transmission [0174] 34 second sub-transmission [0175] 36 gear set (1) [0176] 38 gear set (3) [0177] 40 first gearshift clutch assembly (NE) [0178] 42 gear set (5) [0179] 48 gear set (2) [0180] 50 gear set (4) [0181] 52 second gearshift clutch assembly (D/B) [0182] 56 first electric machine (EM1) [0183] 58 first pinion (first machine pinion) [0184] 59 first intermediate gear [0185] 60 second electric machine (EM2) [0186] 62 second pinion (second machine pinion) [0187] 63 second intermediate gear [0188] 66 third gearshift clutch assembly (K3/C) [0189] 70 first gearwheel (first machine gearwheel) [0190] 72 second gearwheel (second machine gearwheel) [0191] 74 intermediate shaft [0192] 76 transmission arrangement input shaft [0193] A1-A5 axes [0194] A-E gearshift clutches for gear steps [0195] K1 first clutch (separating clutch) [0196] K2 second clutch [0197] K3 third clutch (bridge clutch) [0198] S1-S5 actuating units [0199] P parking interlock gear