Hybridized powertrain with a dual-clutch transmission coupled to an electric machine

Abstract

Hybridized powertrain (1) for a motor vehicle, comprising an internal combustion engine, an electric machine (EM) and a transmission arrangement (5), wherein the transmission arrangement (5) comprises at least one first planetary gear set (PGS1) and is designed as a summing gear, wherein - a first element of the first planetary gear set (PGS1) is rotatably connected to the internal combustion engine and can be fixed directly or indirectly against a housing, wherein the first element of the first planetary gear set (PGS1) is designed as a ring gear (13), - a second element of the first planetary gear set (PGS1) is rotatably connected to the electric machine (EM) by means of a coupling C and can be fixed directly or indirectly against the housing, wherein the second element of the first planetary gear set (PGS1) is designed as a sun gear (11). - a third element of the first planetary gear set (PGS1) is connected to an output (4), wherein the third element of the first planetary gear set (PGS1) is designed as a planet carrier (12), - wherein the ring gear (13) can further be connected to the electric machine (EM) by means of a coupling D, characterized in that the coupling C has an output plate carrier (CA) which is connected to the sun gear (11) of the first planetary gear set (PGS1), wherein the coupling D has an output plate carrier (DA) which is connected to the ring gear (13) of the first planetary gear set (PGS1) and the couplings C and D form a double coupling arrangement (30) and have a common coupling input side (31), wherein the common coupling input side is rotatably connected to the electric machine (EM) and the common coupling input side (31) comprises an input plate carrier (32) which carries plates assigned to both the coupling C and the coupling D and wherein the input plate carrier (32) and the output plate carrier (DA) are rotatably mounted relative to each other.

Description

[0001] The invention relates to a hybridized drivetrain, in particular for a motor vehicle with an internal combustion engine, an electric motor, and a transmission arrangement. Furthermore, the invention relates to a method for controlling a hybridized drivetrain.

[0002] Hybridized powertrains are known in the state of the art in many variations. They comprise a transmission arrangement in the form of one or more spur or planetary gear sets, a drive motor such as an internal combustion engine, and another drive motor such as an electric motor, so that the respective drive power of both motors can be transmitted to the output combined or individually.

[0003] The combustion engine can usually be coupled to the transmission arrangement by means of a starting clutch, whereas the connection of the electric motor to the drive train can in principle be freely determined.

[0004] If the electric machine is arranged in the power flow between the combustion engine and the transmission arrangement or is directly coupled to a transmission shaft of a transmission arrangement, combustion engine gear stages, i.e. gear stages that are in the power flow in pure combustion engine operation, can also be used at least partially by the electric machine.

[0005] Another possibility for connecting the electric machine is to couple it directly or via an additional gear arrangement to the output.

[0006] The connection can usually be made by means of a traction drive, a spur gear stage or a planetary gear, whereby a gear ratio is preferably selected with which the electric machine can be operated in an efficient, high speed range.

[0007] In particular, however, it has proven advantageous if the electric motor is coupled to the output via a summing gear in the form of a planetary gear set, in which a first element of the summing gear is connected to the combustion engine, a second element of the summing gear is connected to the electric motor, and a third element of the summing gear is connected to the output, as disclosed in DE 10 2016 221 735 A1. In this configuration, the power inputs of both drive motors converge in the summing gear. The speeds of both drive motors can be adjusted independently of the other drive motor, which is why the transmission arrangement can exhibit similar driving characteristics to continuously variable transmissions.

[0008] A summation gear consists essentially of three elements: a sun gear, a planet carrier, and a ring gear. Several planet gears are mounted on the planet carrier, rotating around their own axes and around the axis of the sun gear. The choice of which of the three elements is assigned to the sun gear, the planet carrier, or the ring gear is up to you. The power inputs of the combustion engine and the electric motor are input to two different elements of the summation gear and are dissipated via the element of the summation gear connected to the output. For example, the sun gear is connected to the electric motor, the planet carrier to the output, and the ring gear to the gear. Alternatively, the sun gear may be connected to the output, the planet carrier to the gear, and the ring gear to the electric motor, etc.

[0009] Document DE 10 2018 203 563 A1 describes a drivetrain of the type described above with an electric motor and an internal combustion engine. A transmission in the form of two planetary gear sets is arranged upstream of the summing transmission between a summing transmission and the internal combustion engine. In total, this drivetrain thus comprises three planetary gear sets, enabling driving programs such as two purely electric gears, four purely combustion engine gears, and three hybrid gears. Starting the internal combustion engine using the electric motor is also possible while driving, with limitations and taking into account the gear selection and vehicle speed.

[0010] DE 10 2015 216 896 A1 shows a drive device for a hybrid vehicle, with an internal combustion engine and with an electric motor, as well as with a torque superposition device for superimposing the torques generated by the internal combustion engine and the electric motor on an output shaft.

[0011] The torque superposition device comprises a planetary gear arrangement with two coupled planetary gear sets, each planetary gear set having a ring gear, a sun gear and a shifting element, a planet carrier of the first planetary gear set being rotationally coupled to the ring gear of the second planetary gear set, and the output shaft being rotationally coupled to a planet carrier of the second planetary gear set.

[0012] JP 2009-1234 A discloses a drive device of a hybrid vehicle having an engine, a motor generator, and the automatic transmission, which have a plurality of input clutches for forming shift stages. The input clutches consist of mutually engaging input-side engagement elements connected to an output shaft of the engine, and output-side engagement elements, each connected to the input elements of the automatic transmission. A rotor of the motor generator is connected to the output-side engagement element of the input clutch to form the lowest speed stage, which is engaged when the lowest speed stage is set to achieve a maximum shift ratio of the engagement elements, so that power can be transmitted.

[0013] DE 11 2006 002 537 B4 discloses an electrically variable transmission family providing low-cost, low-content electrically variable transmission mechanisms comprising a first and second differential gear set, a battery, two electric motors that interchangeably serve as motors or generators, a dog clutch, and four or five selectable torque-transmitting devices. The differential gear sets are preferably planetary gear sets, but other gear arrangements may be employed, such as bevel gears or a differential gear arrangement on an offset axle.

[0014] Nevertheless, the task remains to improve such drive trains in terms of size and cost and to increase the number of purely electric gears.

[0015] This object is achieved by a hybridized drive train, in particular for a motor vehicle, with an internal combustion engine, an electric machine and a transmission arrangement, wherein the transmission arrangement has at least one first planetary gear set and is designed as a summing transmission, wherein - a first element of the first planetary gear set is or can be connected to the internal combustion engine in a rotationally fixed manner and can be secured against a housing, - a second element of the first planetary gear set can be rotatably connected to the electric machine by means of a coupling C and can be fixed against the housing, - a third element of the first planetary gear set is connected to an output, wherein the first element is further connectable to the electric machine by means of a clutch D.

[0016] With this hybridized drivetrain according to the invention, the summing transmission can receive drive power from the electric motor either via the first element only, via the second element only, or simultaneously from both elements and transmit it to the output, establishing three purely electrically operated gear ratios. Furthermore, however, clutches C and D can also be used to transmit drive power exclusively from the combustion engine to the output, in order to establish a combustion engine-operated gear ratio. The EVT gear ratios known from the prior art can also be implemented without restrictions or the additional use of the electric motor in parallel operation with the combustion engine.The possibility of this multiple use of the two clutches C and D for the realization of electric, combustion engine and hybrid-operated gear stages not only increases the number of gear stages that can be switched, but also reduces the number of clutches required and saves costs.

[0017] "Rotatably connected" or "rotatably connectable" refers to a torque-locking connection. "Lockable against the housing" refers to a friction-locking or positive-locking connection with the housing.

[0018] The first planetary gear set can be simple or in the form of a positive planetary gear.

[0019] The first element of the first planetary gear set can either be directly connected to the combustion engine for rotational movement. A clutch arranged in the power flow between the first element and the combustion engine and / or additional planetary gear sets for reducing the speed of the hybridized drive train are also conceivable.

[0020] In addition, the first element of the planetary gear set can be secured directly against the housing by means of a brake to decelerate this planetary gear set. It is also conceivable to indirectly secure the first element against the housing by using clutches and brakes of the gear arrangement that are not directly assigned to the first planetary gear set, but are intended, for example, to control another planetary gear set.

[0021] The second element of the planetary gear set can preferably be secured directly against the housing by means of a brake B in order to brake this planetary gear set. It is also conceivable to secure the second element against the housing indirectly by using clutches and brakes of the gear arrangement that are not directly assigned to the first planetary gear set, but are intended, for example, to control another planetary gear set.

[0022] Preferably, clutches C and D form a dual clutch arrangement and have a common clutch input side, wherein the common clutch input side is rotationally connected to the electric machine. Preferably, the common clutch input side comprises an input disk carrier that has disks associated with both clutch C and clutch D.

[0023] Preferably, the clutch input side of the dual clutch arrangement is connected to the electric machine (EM) via a gear stage, wherein this gear stage is arranged axially between the brake B and the dual clutch arrangement.

[0024] According to the invention, the first element of the first planetary gear set is designed as a ring gear, the second element of the first planetary gear set is designed as a sun gear and the third element of the first planetary gear set is designed as a planet gear carrier.

[0025] Preferably, the clutch C has an output disk carrier CA which is connected to the sun gear of the first planetary gear set, wherein the clutch D has an output disk carrier which is connected to the ring gear of the first planetary gear set, wherein the input disk carrier and the output disk carrier are rotatably mounted relative to one another.

[0026] In the embodiment according to the invention, clutches C and D are arranged radially interleaved with one another. Furthermore, it is advantageous if clutch D is arranged radially outside of clutch C.

[0027] Preferably, the sun gear of the first planetary gear set is designed as a hollow shaft and is rotatably mounted relative to the planet gear carrier of the first planetary gear set.

[0028] Preferably, the planetary gear carrier of the first planetary gear set is connected to the output via a gear stage, wherein this gear stage is arranged on the side of the drive train opposite the combustion engine.

[0029] In a further advantageous, compact embodiment, however, it is also conceivable to arrange this gear stage axially between the dual clutch arrangement and the first planetary gear set, wherein the electric machine is arranged on the side of the drive train opposite the combustion engine.

[0030] Particularly preferably, the gear arrangement comprises a second planetary gear set, wherein - a planetary gear carrier of the second planetary gear set is rotationally connected to the ring gear of the first planetary gear set, - a sun gear of the second planetary gear set is rotationally connected to the combustion engine, - a ring gear of the second planetary gear set can be locked against the housing by means of a brake E and wherein - the planet gear carrier and the sun gear of the first planetary gear set can be rotatably connected by means of a coupling A.

[0031] This inventive connection of a further planetary gear set results in three purely electric, four purely combustion engine, four hybrid parallel operation and two EVT-operated gear stages during operation.

[0032] The second planetary gear set is preferably arranged axially between the combustion engine and the first planetary gear set.

[0033] Preferably, the drive train comprises only two planetary gear sets, namely the first and the second planetary gear set.

[0034] Furthermore, it is advantageous if the internal combustion engine is rotationally connected exclusively to the sun gear of the second planetary gear set and is further connectable exclusively via the clutch A to the planet gear carrier of the second planetary gear set.

[0035] Preferably, the first and second planetary gear sets are connected to one another exclusively by a rotationally fixed connection between the ring gear of the first planetary gear set and the planet gear carrier of the second planetary gear set, so that the second planetary gear set is arranged between the first planetary gear set and the combustion engine in the power flow direction - with respect to the drive power of the combustion engine.

[0036] Preferably, the electric machine is arranged parallel to the first and second planetary gear sets.

[0037] In an advantageous method for controlling a drive train, it is proposed that a purely electrically operated gear stage, in particular a third purely electrically operated gear stage, be established by engaging clutches C and D. This measure indirectly connects two elements of the first planetary gear set to one another for rotation, thus interlocking this planetary gear set. Instead of an additional clutch required for directly coupling these two elements, clutches C and D can be used, which are also intended for the respective connection to the electric motor.

[0038] Preferably, a purely combustion engine gear stage, in particular a second purely combustion engine gear stage, is established by closing the clutches C and D and the brake E.

[0039] Preferably, a hybridized gear stage is engaged in which the third purely electric gear stage and the second combustion engine gear stage are engaged in combination.

[0040] The invention is described below by way of example with reference to the accompanying drawings. Fig. 1 shows a hybridized drive train according to the invention according to a first embodiment. Fig. 2 shows a circuit diagram for a hybridized powertrain according to the first embodiment. Fig. 3 shows a hybridized drive train according to the invention according to a second embodiment. Fig. 4 shows a circuit diagram for a hybridized powertrain according to the second embodiment.

[0041] The Fig. The hybridized powertrain 1 shown in Figure 1 comprises an internal combustion engine (not shown), a dual-mass flywheel, a transmission input shaft 3, a transmission arrangement 5, an electric machine EM, an output 4 and a housing.

[0042] The gear arrangement 5 comprises a first planetary gear set PGS1, which in turn has a first element which is designed as a ring gear 13, a second element which is designed as a sun gear 11, and a third element which is designed as a planet gear carrier 12.

[0043] In addition, the gear arrangement 5 has a second planetary gear set PGS2 comprising a sun gear 21, a planet gear carrier 22 and a ring gear 23.

[0044] The sun gear 21 is non-rotatably connected to the internal combustion engine via the transmission input shaft and the dual-mass flywheel. A clutch A connects the sun gear 21 to the planetary gear carrier 22, thus locking the second planetary gear set PGS2. Furthermore, the ring gear 23 can be secured against the housing by a brake E, allowing the second planetary gear set PGS2 to operate in the braked state.

[0045] The first and second planetary gear sets PGS1, PGS2 are coupled to each other exclusively via a rotationally fixed connection between the ring gear 13 and the planetary gear carrier 22. The power flow of the drive power of the combustion engine runs via the second planetary gear set PGS2 to the ring gear 13 of the first planetary gear set PGS1.

[0046] The first planetary gear set PGS1 is designed as a summing gear, meaning the power inputs of both drive motors converge in the first planetary gear set and are transferred to the output via the planetary gear carrier 12 and a spur gear stage 7. The electric motor EM can be connected to the first planetary gear set by means of a dual clutch arrangement 30 comprising a clutch C and D. Clutch C can establish a rotationally fixed connection between the sun gear 11 and the electric motor EM. Furthermore, the electric motor EM can be connected to the ring gear 13 by means of clutch D.

[0047] The drive power of the electric machine EM is fed either only into the sun gear 11, only into the ring gear 13 or, as soon as both clutches C and D are closed, both into the sun gear 11 and the ring gear 13 simultaneously into the first planetary gear set.

[0048] If the two clutches C and D are closed, the first planetary gear set PGS1 is in the locked state.

[0049] Clutches C and D have a common clutch input side 31, wherein the common clutch input side 31 is rotationally connected to the electric machine EM. Furthermore, the common clutch input side 31 comprises an input disk carrier 32, which carries disks associated with both clutch C and clutch D.

[0050] In addition, the clutch input side 31 is rotationally connected to the electric machine EM via a gear stage 6, wherein the electric machine is arranged parallel to the transmission arrangement.

[0051] By means of a brake B, the sun gear 11 can be directly locked against the housing, whereby the first planetary gear set can be operated in the braked state.

[0052] The gear stage 6 is arranged axially between the brake B and the dual clutch arrangement.

[0053] In this exemplary embodiment, a gear stage 7, which rotatably connects the planetary gear carrier to the output 4, is arranged on the side opposite the combustion engine in the hybridized drive train 1.

[0054] The hybridized drive train 1 is designed to provide four purely combustion engine gear stages by operating the first and second planetary gear sets (PGS1 and PGS2) in a combination of block gearing and planetary gear ratios. For example, a first combustion engine gear stage is provided according to the shift pattern in Fig. 2 is engaged when brake B and brake E are closed, meaning both planetary gear sets PGS1 and PGS2 are braked and rotate in their respective gear ratios. In the second internal combustion engine gear stage, both clutches C and D are closed, thus locking the first planetary gear set, while the second planetary gear set PGS2 remains in the braked state.

[0055] Furthermore, the hybridized drive train 1 is designed to support the four internal combustion engine gear stages by switching on the electric motor EM in parallel operation or to drive them in a recuperation mode. In this case, the clutch D is additionally closed, unless it is already engaged by an internal combustion engine gear stage according to the shift pattern in Fig. 2 is used.

[0056] The first and second electrically operated gear stages are set up by closing one of the two clutches C or D and at the same time the first planetary gear set PGS1 is in the braked state.

[0057] The braked state can occur directly or indirectly. If the ring gear 13 is to be driven by the motor EM (second electric gear stage), the first planetary gear set PGS1 is directly braked by brake B, which locks the sun gear 11 against the housing. If, however, the sun gear 11 is to be driven by the electric motor EM (first electrically operated gear stage), the first planetary gear set PGS1 is indirectly braked by locking the ring gear 13 against the housing by brake E and clutch A. Brake E and clutch A are not directly assigned to the first planetary gear set, but rather to the second planetary gear set.

[0058] According to the invention, the third purely electrically operated gear stage is established by closing clutches C and D.

[0059] Another special feature of the hybridized powertrain 1 is the ability to operate both drive motors at different speeds in what is known as EVT mode. In this continuously variable operation, the electric motor is connected exclusively to sun gear 11 via clutch C, while the combustion engine power flows into ring gear 13. The first planetary gear set therefore remains unbraked.

[0060] In total, this results in three purely electric, four purely combustion engine, four hybrid parallel operation and two EVT-operated gear stages.

[0061] The Fig. The hybridized powertrain 1 shown in Figure 3 shows a second embodiment and contains essentially the same components and a similar structure as the one shown in Fig. 1, which is why the same reference numerals have been used. The key difference is the connection of both drive motors and the output to the first planetary gear set / summation gear. Thus, the first element of the first planetary gear set is assigned to the ring gear 11. The second element is assigned to the planet gear carrier 12, and the third element is assigned to the ring gear 13.

[0062] Furthermore, the first planetary gear set PGS1 is designed as a positive planetary gear.

[0063] Furthermore, gear stage 6 in the hybridized drivetrain is located on the side opposite the combustion engine. In contrast, gear stage 7 is located between the dual clutch arrangement 30 and the first planetary gear set PGS1.

[0064] The functionality is identical to the first embodiment. The type and number of gear steps remain the same. Due to the different connections of the drive motors and the output to the first planetary gear set PGS1, shorter ratios of the first gears result, thereby increasing the ratio spread. A shift logic optimized for operation is the Fig. 4. List of reference symbols 1 drivetrain 3 Gearbox input 4 downforce 5 Gear arrangement 6 gear stage 7 gear stage 11 Sun gear of the first planetary gear set 12 Planet gear carrier of the first planetary gear set 13 Ring gear of the first planetary gear set 21 Sun gear of the second planetary gear set 22 Planetary gear carrier of the second planetary gear set 23 Ring gear of the second planetary gear set 30 dual clutch arrangement 31 Clutch input side 32 input slat carriers CA Output plate carrier of clutch C CD Output plate carrier of clutch D EM Electric Machine PGS1 First planetary gear set PGS2 Second planetary gear set A clutch B Brake C clutch D clutch E brake

Claims

[1] Hybridized drive train (1) for a motor vehicle, comprising an internal combustion engine, an electric machine (EM) and a transmission arrangement (5), wherein the transmission arrangement (5) has at least one first planetary gear set (PGS1) and is designed as a summing transmission, wherein - a first element of the first planetary gear set (PGS1) is rotatably connected to the internal combustion engine and can be fixed directly or indirectly against a housing, wherein the first element of the first planetary gear set (PGS1) is designed as a ring gear (13), - a second element of the first planetary gear set (PGS1) is rotatably connected to the electric machine (EM) by means of a clutch C and can be fixed directly or indirectly against the housing, wherein the second element of the first planetary gear set (PGS1) is designed as a sun gear (11) - a third element of the first planetary gear set (PGS1) is connected to an output (4), wherein the third element of the first planetary gear set (PGS1) is designed as a planetary gear carrier (12), - wherein the ring gear (13) is further connectable to the electric machine (EM) by means of a clutch D, characterized byin that the clutch C has an output plate carrier (CA) which is connected to the sun gear (11) of the first planetary gear set (PGS1), wherein the clutch D has an output plate carrier (DA) which is connected to the ring gear (13) of the first planetary gear set (PGS1), and the clutches C and D form a double clutch arrangement (30) and have a common clutch input side (31), wherein the common clutch input side is rotationally connected to the electric machine (EM) and the common clutch input side (31) comprises an input plate carrier (32) which carries plates assigned to both the clutch C and the clutch D, and wherein the input plate carrier (32) and the output plate carrier (DA) are rotatably mounted relative to one another. [2] Drive train according to claim 1, characterized bythat the second element of the planetary gear set can be locked against the housing by means of a brake B and the clutch input side (31) of the double clutch arrangement is connected to the electric machine (EM) via a gear stage (6), this gear stage (6) being arranged axially between the brake B and the double clutch arrangement. [3] Drive train according to one of the preceding claims, characterized by that the sun gear (11) of the first planetary gear set (PGS1) is designed as a hollow shaft and is rotatably mounted to the planet gear carrier (12) of the first planetary gear set (PGS1). [4] Drive train according to one of the preceding claims, characterized by that the planet gear carrier (12) of the first planetary gear set (PGS1) is connected to the output (4) via a gear stage (7), said gear stage (7) being arranged on the side opposite the internal combustion engine in the drive train (1). [5] Drive train according to one of the preceding claims, characterized by that the gear arrangement (5) further comprises a second planetary gear set (PGS2), wherein - a planetary gear carrier (22) of the second planetary gear set (PGS2) is rotationally connected to the ring gear (13) of the first planetary gear set (PGS1), - wherein a sun gear (11) of the second planetary gear set (PGS2) is rotationally connected to the internal combustion engine, - a ring gear (23) of the second planetary gear set (PGS2) can be locked against the housing by means of a brake E and - wherein the planet gear carrier (12) and the sun gear (11) of the first planetary gear set (PGS1) are rotatably connected by means of a clutch A. [6] Drive train according to claim 5, characterized by that the drive train (1) comprises only two planetary gear sets (PGS1 and PGS2). [7] Drive train according to claim 5 or 6, characterized bythat the internal combustion engine is rotationally connected exclusively to the sun gear (21) of the second planetary gear set (PGS2) and is further connectable exclusively via the clutch A to the planet gear carrier (22) of the second planetary gear set (PGS2). [8] Drive train according to one of claims 5 to 7, characterized by that the first and second planetary gear sets (PGS1 and PGS2) are connected to one another exclusively by a rotationally fixed connection between the ring gear (13) of the first planetary gear set (PGS1) and the planet gear carrier (22) of the second planetary gear set (PGS2). [9] Method for controlling a drive train according to one of the preceding claims, characterized by that a third purely electric gear stage is established by closing clutches C and D. [10] Method for controlling a drive train according to claim 9, characterized bythat a second purely combustion engine gear stage is established by closing clutches C and D and brake E. [11] Method for controlling a drive train according to claim 9, characterized by that a hybridized gear stage is set up in which the third purely electric gear stage and the second combustion engine gear stage are engaged in combination.

Images