Hybrid Drive Train for a Motor Vehicle

Abstract

A hybrid drive train for a motor vehicle includes a drive shaft that is connectable to an internal combustion engine, a first input shaft connected to the drive shaft or connectable to the drive shaft via a first clutch, a second input shaft, an output shaft arrangement, a first electric machine connected to the second input shaft, and a transmission arrangement that includes: (i) a first gear set plane with at least one shiftable gear set via which the first input shaft is connectable to the output shaft arrangement; (ii) a second gear set plane with at least one shiftable gear set via which the second input shaft is connectable to the output shaft arrangement; and (iii) a third gear set plane with at least one gear set via which the output shaft arrangement is connected to a power distribution unit configured for driving driven wheels.

Claims

1-15. (canceled)

16. A hybrid drive train (10) for a motor vehicle, comprising: a drive shaft (14) connectable to an internal combustion engine (12); a first input shaft connected to the drive shaft (14) or connectable to the drive shaft (14) via a first clutch (K0); a second input shaft (26); an output shaft arrangement (28); a first electric machine (64) connected to the second input shaft (26); and a transmission arrangement comprising a first gear set plane (34) with at least one shiftable gear set via which the first input shaft (24) is connectable to the output shaft arrangement (28), a second gear set plane (42) with at least one shiftable gear set via which the second input shaft (26) is connectable to the output shaft arrangement (28), and a third gear set plane (50) with at least one gear set via which the output shaft arrangement (28) is connected to a power distribution unit (18) for driving driven wheels (20L, 20R).

17. The hybrid drive train of claim 16, wherein the first input shaft (24) and the second input shaft (26) are connectable via a second clutch (K3).

18. The hybrid drive train of claim 16, wherein the output shaft arrangement (28) comprises a first output shaft (30) and a second output shaft (32).

19. The hybrid drive train of claim 18, wherein the first gear set plane (34) comprises a fixed gear (36) connected to the first input shaft (24), an idler gear (38) mounted at the first output shaft (30), and an idler gear (40) mounted at the second output shaft (32).

20. The hybrid drive train of claim 18, wherein the second gear set plane (42) comprises a fixed gear (44) connected to the second input shaft (26), an idler gear (46) mounted at the first output shaft (30), and an idler gear (48) mounted at the second output shaft (32).

21. The hybrid drive train of claim 18, wherein the third gear set plane (50) comprises a first output gearwheel (52) fixed at the first output shaft (30) and a second output gearwheel (54) fixed at the second output shaft (32), the first and second output gearwheels (52, 54) engaged with an input element (58) of the power distribution unit (18).

22. The hybrid drive train of claim 16, wherein the third gear set plane (50) comprises an idler gear (56) rotatably mounted at the first input shaft (24) and engaged with a fixed gear (54), the fixed gear (54) fixed at an output shaft (32) of the output shaft arrangement (28).

23. The hybrid drive train of claim 22, wherein the idler gear (56) rotatably mounted at the first input shaft (24) is connectable to the first input shaft (24) by a gearshift clutch (D), the first input shaft (24) and the second input shaft (26) are connectable via a second clutch (K3), and the gearshift clutch (D) and a second clutch (K3) are alternately actuatable by an actuation device (S2).

24. The hybrid drive train of claim 16, wherein the third gear set plane (50) is arranged in an axial direction between the first gear set plane (34) and the second gear set plane (42).

25. The hybrid drive train of claim 16, wherein a first clutch plane (60) is arranged adjacent the first gear set plane (34).

26. The hybrid drive train of claim 25, wherein the first clutch plane (60) is arranged on an axial side of the first gear set plane (34) facing away from the third gear set plane (50).

27. The hybrid drive train of claim 16, wherein a second clutch plane (62) is arranged adjacent the second gear set plane (42).

28. The hybrid drive train of claim 27, wherein the second clutch plane (62) is arranged in an axial direction between the second gear set plane (42) and the third gear set plane (50).

29. The hybrid drive train of claim 16, wherein a starting torque ratio (i1) is formed by a gear set of the second gear set plane (42).

30. The hybrid drive train of claim 16, further comprising a second electric machine (72) connected to the first input shaft (24).

31. The hybrid drive train of claim 16, further comprising one or more of the first clutch (K0), a second clutch (K3), and at least one gearshift clutch (A, B, C, E) is configured as a dog clutch.

32. The hybrid drive train of claim 16, wherein a rotor (70) of the first electric machine (64″) is connected to the second input shaft (26) via a pre-ratio (80).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Exemplary embodiments of the invention are represented in the drawing and are explained in greater detail in the following description, wherein

[0082] FIG. 1 shows a schematic of a first example embodiment of a hybrid drive train according to the invention;

[0083] FIG. 2 shows a power flow diagram of the hybrid drive train from FIG. 1;

[0084] FIG. 3 shows a gearshift table for internal combustion engine gear steps of the hybrid drive train from FIG. 1;

[0085] FIG. 4 shows a gearshift table for electric motor gear steps of the hybrid drive train from FIG. 1;

[0086] FIG. 5 shows one further example embodiment of a hybrid drive train according to the invention; and

[0087] FIG. 6 shows one further example embodiment of a hybrid drive train according to the invention.

DETAILED DESCRIPTION

[0088] 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.

[0089] In FIG. 1, a hybrid drive train for a motor vehicle, in particular a passenger car, is diagrammatically represented and is labeled, in general, with 10.

[0090] The hybrid drive train 10 includes an internal combustion engine 12, the crankshaft of which is fixedly connected to a drive shaft 14.

[0091] The hybrid drive train 10 includes, furthermore, a hybrid transmission arrangement 16, which can guide drive power provided by the drive shaft 14 onto a power distribution unit 18, which is designed for distributing drive power onto driven wheels 20L, 20R of the motor vehicle.

[0092] Moreover, the hybrid drive train 10 includes a control device 22 for controlling various components of the hybrid drive train of the type explained in the following.

[0093] The hybrid drive train 16 includes a first input shaft 24, which is arranged coaxially to the drive shaft 14. Moreover, the hybrid transmission arrangement 16 includes a second input shaft 26, which is arranged coaxially to the first input shaft 24 and, in fact, in the form of a hollow shaft, which is arranged, at least in sections, around the first input shaft 24.

[0094] The hybrid transmission arrangement 16 includes, furthermore, an output shaft arrangement 28 including a first output shaft 30 and a second output shaft 32. The first and the second output shafts 30, 32 are arranged axially parallel to the input shaft arrangement, which is formed by the first input shaft 24 and the second input shaft 26.

[0095] The hybrid transmission arrangement 16 includes, furthermore, a first gear set plane 34. The first gear set plane 34 includes a fixed gear 36, which is fixedly connected to the first input shaft 24, an idler gear 38, which is rotatably mounted at the first output shaft 30, and an idler gear 40, which is rotatably mounted at the second output shaft 32. The idler gears 38, 40 are both in engagement with the fixed gear 36.

[0096] Moreover, the hybrid transmission arrangement 16 includes a second gear set plane 42. The second gear set plane 42 includes a fixed gear 44, which is fixedly connected to the second input shaft 26, an idler gear 46, which is rotatably mounted at the first output shaft 30, and an idler gear 48, which is rotatably mounted at the second output shaft 32. The idler gears 46, 48 are both in engagement with the fixed gear 44.

[0097] Moreover, the hybrid transmission arrangement 16 includes a third gear set plane 50. The third gear set plane 50 includes a first output gearwheel 52, which is fixedly connected to the first output shaft 30, and a second output gearwheel 54, which is fixedly connected to the second output shaft 32. Moreover, the third gear set plane 50 includes an idler gear 56, which is rotatably mounted at the first input shaft 24 and is in engagement with the second output gearwheel 54.

[0098] An input element of the power distribution unit 18 is formed by a drive gear 58, which is in engagement with the first output gearwheel 52 as well as with the second output gearwheel 54.

[0099] The hybrid transmission arrangement 16 includes, furthermore, a first clutch plane 60. The first clutch plane 60 includes a gearshift clutch B, by which the idler gear 38 is connectable to the first output shaft 30, and a gearshift clutch C, by which the idler gear 40 is connectable to the second output shaft 32.

[0100] In the present case, the first clutch plane 60 includes, furthermore, a first clutch K0, which is arranged between the output shaft 14 and the first input shaft 24 and, in fact, coaxially thereto. The first clutch K0 therefore forms a separating clutch between the hybrid transmission arrangement 16 and the internal combustion engine 12.

[0101] The hybrid transmission arrangement 16 includes, furthermore, a second clutch plane 62. The second clutch plane 62 includes a gearshift clutch A, by which the idler gear 46 is connectable to the first output shaft 30, and a gearshift clutch E, by which the idler gear 48 is connectable to the second output shaft 32.

[0102] Moreover, the second clutch plane 62 includes a gearshift clutch D, by which the idler gear 56 is connectable to the first input shaft 24. The gearshift clutch D and a second clutch K3 form, in the present case, a gearshift clutch assembly, which is arranged in the second clutch plane 62 and is designed for engaging either the gearshift clutch D or the second clutch K3. Moreover, the gearshift clutch assembly can establish a neutral position, in which neither the gearshift clutch D nor the second clutch K3 is engaged.

[0103] The input shaft arrangement is situated on an axis A1. The first output shaft 30 is situated on an axis A2. The second output shaft 32 is situated on an axis A3. The power distribution unit 18 is situated on an axis A4.

[0104] The following actuation devices are provided for actuating the gearshift clutches A through E as well as the first clutch K0 and the second clutch K3: A first actuation device S1 is designed for disengaging or engaging the first clutch K0. A second actuation device S2 is designed for either engaging the gearshift clutch D or engaging the second clutch K3 or establishing a neutral position therebetween, in which neither D nor K3 is engaged.

[0105] A third actuation device S3 is associated with the gearshift clutches A and E and is designed for either engaging the gearshift clutch A or engaging the gearshift clutch E or establishing a neutral position, in which neither the gearshift clutch A nor the gearshift clutch E is engaged.

[0106] A fourth actuation device S4 is associated with the gearshift clutches B and C. The fourth actuation device S4 is designed for either engaging the gearshift clutch B or engaging the gearshift clutch C or establishing a neutral position, in which neither the gearshift clutch B nor the gearshift clutch C is engaged.

[0107] The third gear set plane 50 is arranged in the axial direction between the first gear set plane 34 and the second gear set plane 42. The first clutch plane 60 is arranged on a side of the first gear set plane 34 axially opposite the third gear set plane 50. The second clutch plane 62 is arranged in the axial direction between the second gear set plane 42 and the third gear set plane 50.

[0108] Starting from the side of the internal combustion engine 12, the order of the planes is, therefore, as follows: 60, 34, 50, 62, 42.

[0109] The hybrid transmission arrangement 16 includes, furthermore, a first electric machine 64 (EMI). The first electric machine 64 is arranged coaxially to the input shaft arrangement 24, 26 and is axially arranged on a side of the second gear set plane 42 opposite the second clutch plane 62. In other words, the internal combustion engine 12 and the first electric machine 64 are arranged on axially opposite sides of the hybrid drive train 10.

[0110] The first electric machine 64 includes a stator 66, which is fixedly connected to a housing 68. Moreover, the first electric machine 64 includes a rotor 70, which is rigidly connected to the second input shaft 26.

[0111] The hybrid transmission arrangement 16 includes, furthermore, a second electric machine 82 (EM2). The second electric machine 72 includes an electric machine shaft 74, which is axially parallel to and offset from the input shaft arrangement 24, 26 and the output shafts 30, 32. A gearwheel 76 is fixed at the electric machine shaft 74 and is in engagement with the fixed gear 36 of the first gear set plane 34. The second electric machine 72 is therefore connected to the first input shaft 24.

[0112] The second electric machine 72 is arranged on an axis A5.

[0113] In FIG. 1, it is indicated, furthermore, that a parking interlock gear P can be fixedly connected to one of the output shafts 30, 32 in order to establish a parking lock function, in the present case to the first output shaft 30 and, in fact, in the axial direction between the second gear set plane 42 and the first electric machine 64. The parking interlock gear P can also be arranged at another point, however, for example, at the second output shaft 32 and, in fact, at any point as viewed in the axial direction.

[0114] The hybrid drive train 10 therefore includes seven pairs of spur gears and seven gear change elements (first and second clutches K0, K3 and five gearshift clutches A through E). Moreover, the hybrid drive train has five axes A1 through A5 and two output shafts 30, 32. Moreover, the hybrid drive train preferably includes two electric machines 64, 72.

[0115] The rated power of the first electric machine 64 is preferably greater than the rated power of the second electric machine 74.

[0116] In FIG. 2, the hybrid drive train 10 is represented in such a way that the power flow is apparent. For example, power can flow from the internal combustion engine 12 via the first clutch K0 and the gearshift clutch D to the power distribution unit 18, or from the first electric machine 64 via the engaged second clutch K3 and the gearshift clutch B to the power distribution unit 18, to name a few examples.

[0117] FIG. 3 shows a gearshift table for internal combustion engine gear steps V1 through V4. In all these gear steps, the clutch K0 (if provided) is engaged (indicated by an X in the gearshift table from FIG. 3).

[0118] An internal-combustion-engine starting gear step V1 is established, in that the gearshift clutch A and the second clutch K3 are additionally engaged. Power flows from the internal combustion engine via the first input shaft 24 and the second clutch K3 to the gearshift clutch A and, from there, to the first output shaft 30. The ratio established as a result is i.sub.1. The output ratio i.sub.ab1 is also established. These ratios, which will not be referenced in greater detail in the following, are represented in FIGS. 1 and 2.

[0119] The second internal combustion engine gear step V2 is established by engaging the gearshift clutch B (the second clutch K3 is disengaged again in this case).

[0120] The internal combustion engine gears V3 and V4 are established by engaging the gearshift clutches C and D, respectively.

[0121] A driving operation under purely electric motor power by the second electric machine 72 is established in the same way as represented in FIG. 3, wherein, however, the first clutch K0 is disengaged in order to not need to entrain the internal combustion engine 12.

[0122] In FIG. 4, a gearshift table for a driving operation under electric motor power by the first electric machine 64 is represented. A starting gear step E1.1 is established, in that exclusively the gearshift clutch A is engaged. In all these electric motor gears E1.1 through E1.4, the first clutch K0, if present, remains disengaged.

[0123] A second electric motor gear step E1.2 is established by engaging the gearshift clutch E.

[0124] A third electric motor gear step E1.3 is established by engaging the gearshift clutches B, C and the second clutch K3.

[0125] A fourth electric motor gear step E1.4 is established by engaging the gearshift clutch C and the second clutch K3.

[0126] The hybrid transmission arrangement 16 does not have a dedicated reverse gear. An operation in reverse is generally established by the first electric machine 64 and/or by the second electric machine 72.

[0127] Driving can take place purely electrically with both electric machines 64, 72. Powershifts are possible in the purely electric driving operation, in that the first electric machine 64 supports the tractive force when the second electric machine 72 shifts, and vice versa. A shift sequence of this type is described in detail in the document DE 10 2011 005 451 A1 mentioned at the outset.

[0128] In the internal-combustion-engine or hybrid mode, the first clutch K0 always remains engaged. Therefore, the internal combustion engine 12 is always connected to the second electric machine 72.

[0129] The following functions can be covered with the second electric machine 72:

[0130] internal combustion engine start during purely electric driving;

[0131] supply of the main power circuit;

[0132] serial creeping and driving forward/backwards; and

[0133] support of the closed-loop control of the rotational speed of the internal combustion engine during coupling and during gear shifts.

[0134] In particular, the internal combustion engine can be coupled into all forward gear steps V1 through V4 when the first electric machine 64 utilizes the gear step E1.1. The internal combustion engine can be coupled into the internal combustion engine gear steps V2 through V3 when the first electric machine 64 utilizes the gear step E1.2. The second electric machine 64 can provide support during the unloading of the shift elements K3, B, C, D, in that the second electric machine 72 operates as a generator. The generated current can be utilized by the first electric machine 64 for supporting tractive force.

[0135] The following functions can be covered with the first electric machine 64: [0136] an electric vehicle drive for pulling away from rest and driving forward/backwards; and [0137] supporting the tractive force during gear shifts under internal combustion engine power.

[0138] The first electric machine 64 can maintain the tractive force via E1.1 or E1.2 when a change-over takes place at the shift elements K3, B, C, D. The first electric machine 64 can be connected to the internal combustion engine 12 via the shift element K3. In this way, the first electric machine 64 can start the internal combustion engine or act as a generator in order to generate power for a consumer, for example, when the vehicle is stationary.

[0139] A powershift from V1 to V2 is carried out in the hybrid mode as follows: [0140] The starting point is, for example, the gear step V1, in which K0, K3, and A are engaged. Thereafter, a load reduction takes place at the shift element K3 and a simultaneous load build-up takes place at the first electric machine 64. The load reduction can take place, in that the internal combustion engine 12 and the second electric machine 72 reduce the torque or when the second electric machine 72 compensates for the internal combustion engine torque while acting as a generator, and so the sum of the torques of the internal combustion engine 12 and of the second electric machine 72 is approximately zero. Thereafter, the shift element K3 is disengaged. Thereupon, the rotational speed of the internal combustion engine 12 and of the second electric machine 72 is reduced, and so the shift element B is synchronized. For this purpose, the second electric machine 72 can operate, for example, as a generator (which is preferred), or the internal combustion engine 12 can enter the coasting condition. Finally, the shift element B can be engaged in order to engage the forward gear step V2.

[0141] In the hybrid mode, a reduction of the rotational speed of the first electric machine 64 is also possible. When the second clutch K3 is disengaged, a change-over from the first electric machine 64 to the second electric machine 72 can take place in the background without load. As a result, the rotational speed of the first electric machine 64 is reduced. This change-over can take place while the internal combustion engine 12 (and/or the second electric machine 72) maintain(s) the tractive force in one of the gears V2 through V4.

[0142] In the hybrid mode, the first electric machine 64 can be decoupled when the internal combustion engine 12 utilizes one of the gears V2 through V4. In this way, an efficient driving operation under internal combustion engine power is possible.

[0143] The second electric machine 72 can be dimensioned smaller, if necessary, than the first electric machine 64, since the second electric machine 72 does not need to perform essential driving functions.

[0144] The aforementioned example variants also apply for the case in which a first clutch K0 is not present, i.e., the output shaft 14 is rigidly connected to the first input shaft 24.

[0145] Due to the measure that the second electric machine 72 is connected to the fixed gear 36 of the first gear set plane 34, a separate fixed gear is not necessary therefor.

[0146] Further example embodiments of hybrid drive trains, which generally correspond to the hybrid drive train 10 from FIGS. 1 through 4 with regard to configuration and mode of operation, are described below. Identical elements are therefore labeled with identical reference characters. In the following, essentially, the differences are explained.

[0147] In FIG. 5, a simplified example hybrid drive train 10′ is represented, which includes neither a second electric machine 72 nor a first clutch K0. As compared to the example hybrid drive train 10 from FIGS. 1 through 4, the following driving operations are then inherently no longer possible: a serial driving operation (a serial driving operation is understood, in general, to mean that, when two electric machines are present, a driving operation is established by one electric machine and the internal combustion engine is utilized for operating the other electric machine as a generator and recharging the battery).

[0148] An internal combustion engine start during purely electric driving is also not possible. A purely electric powershift is also not possible. A support of the closed-loop control of the rotational speed of the internal combustion engine during coupling and during gear shifts is also not possible.

[0149] Otherwise, the hybrid drive train 10′ can also perform all the aforementioned functions.

[0150] One further example hybrid drive train 10″ is represented in FIG. 6. This corresponds to the example hybrid drive train from FIG. 1, wherein a first clutch K0 is not provided, however. One further difference is that the first electric machine 64″ is not directly connected with the rotor 70 of the first electric machine 64″ to the second input shaft 26. Rather, the rotor 70 of the first electric machine 64″ is connected to the second input shaft 26 via a pre-ratio 80.

[0151] In the present case, the pre-ratio 80 is implemented by a planetary gear set 82, which includes a ring gear 84, a sun gear 86, and a planet carrier 88. The ring gear 84 is connected to the rotor 70. The sun gear 86 is fixed at the housing 68. The planet carrier 88 is connected to the second input shaft 26.

[0152] In all the aforementioned example embodiments, the first clutch K0, which, as is also the case for the gearshift clutches A through E and the second clutch K3, can be designed as a dog clutch (in particular when the second electric machine 72 is present), and can also be implemented as a friction clutch. In this case, it is advantageous that the first clutch K0 can also be disengaged under load, for example, during a full brake application or in the case of a malfunction in the internal combustion engine 12. A first clutch K0 designed as a friction clutch can also be engaged at a differential speed. As a result, a “flywheel start” of the internal combustion engine 12 by the second electric machine 72 is possible (the inertial mass of the second electric machine 72 is utilized for starting the internal combustion engine 12).

[0153] The hybrid drive train 10″ from FIG. 6 is provided, in particular, for hybrid drive trains of the type in which the available electrical energy accumulator has relatively small dimensions. In this case, the possibilities of a purely electric driving operation with one or two electric machines are limited.

[0154] The hybrid drive train 10″ from FIG. 6 therefore provides that the second electric machine 72 is generally not utilized for driving the vehicle. Rather, the second electric machine 72 is generally operated only as a generator.

[0155] For this case, it is useful to equip the first electric machine 64 with the pre-ratio 80. In this way, high torques can be achieved in the purely electric driving operation, also without support of the second electric machine 72, only by the first electric machine 64. Since a purely electric driving operation with both electric machines is not necessary, a first clutch K0 can be omitted.

[0156] 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

[0157] 10 hybrid drive train [0158] 12 internal combustion engine [0159] 14 input shaft [0160] 16 hybrid transmission arrangement [0161] 18 power distribution unit [0162] 20 driven wheels [0163] 22 control device [0164] 24 first input shaft [0165] 26 second input shaft [0166] 28 output shaft arrangement [0167] 30 first output shaft [0168] 32 second output shaft [0169] 34 first gear set plane [0170] 36 fixed gear [0171] 38 idler gear [0172] 40 idler gear [0173] 42 second gear set plane [0174] 44 fixed gear [0175] 46 idler gear [0176] 48 idler gear [0177] 50 third gear set plane [0178] 52 first output gearwheel [0179] 54 second output gearwheel [0180] 56 idler gear [0181] 58 drive gear (18) [0182] 60 first clutch plane [0183] 62 second clutch plane [0184] 64 first electric machine EM1 [0185] 66 stator [0186] 68 housing [0187] 70 rotor [0188] 72 second electric machine EM2 [0189] 74 electric machine shaft [0190] 76 gearwheel [0191] 80 pre-ratio [0192] 82 planetary gear set [0193] 84 ring gear [0194] 86 sun gear [0195] 88 planet carrier [0196] A1-A5 axes [0197] A-E gearshift clutches for gear-step gear sets [0198] K0 first clutch [0199] K3 second clutch [0200] S1-S4 actuation devices [0201] P parking interlock gear