Motor vehicle powertrain

A vehicle powertrain includes first and second power sources and a transmission assembly having first and second input members and an output member. The transmission assembly also includes a first multiple node planetary gear-set connected to both input members and a second multiple node planetary gear-set connected to the output member. The transmission assembly additionally includes a transmission housing retaining the first and second gear-sets. Furthermore, the transmission assembly includes a first torque-transmitting device for connecting one second gear-set node to the transmission housing and a second torque-transmitting device for connecting one first gear-set node to one second gear-set node. One first gear-set node is directly and continuously connected to one second gear-set node. The first and second power sources are connected to the first gear-set, and the first power source is connected to the first gear-set node not directly and continuously connected to the second gear-set.

INTRODUCTION

The disclosure relates to electric and hybrid-electric powertrains for a motor vehicle.

Modern motor vehicles are typically configured as either two- or all-wheel-drive. Either type of a vehicle may employ a powertrain with a single power source, such as an internal combustion engine or an electric motor, used to propel the vehicle, or a hybrid powertrain, where two or more distinct power sources, such as an internal combustion engine and an electric motor, are used to accomplish the same task. Vehicle drive wheels may receive power from each such combination of power sources. As such, a representative powertrain may be used to power a two-wheel-drive or an all-wheel-drive vehicle.

An all-wheel-drive vehicle using a hybrid powertrain may be configured as an axle-split vehicle. In such an all-wheel-drive hybrid vehicle, one or more power sources, such as an internal combustion engine alone or with an electric motor, on one axle, and another power source on another axle, may be set up to independently power the respective vehicle axles to generate on-demand all-wheel-drive propulsion. In such a vehicle, an engine with an electric motor connected to the same axle may be configured to channel their respective torque outputs through a transmission assembly to effectively provide a power-split electro-mechanical hybrid powertrain.

SUMMARY

A powertrain for a motor vehicle includes a first power source configured to generate a first torque output, a second power source configured to generate a second torque output, and a transmission assembly. The transmission assembly includes a first input member, a second input member, and an output member. The transmission assembly also includes a first planetary gear-set having a plurality of nodes and operatively connected to each of the first and second input members, and a second planetary gear-set having plurality of nodes and operatively connected to the output member. The transmission assembly additionally includes a transmission housing configured to retain the first and second planetary gear-sets. Furthermore, the transmission assembly includes a first torque-transmitting device configured to selectively connect or ground one node of the second planetary gear-set to the transmission housing and a second torque-transmitting device configured to selectively connect one node of the first planetary gear-set to one node of the second planetary gear-set. One node of the first planetary gear-set is directly and continuously connected to one node of the second planetary gear-set. Each of the first power source and the second power source is operatively connected to the first planetary gear-set, and the first power source is operatively connected to the node of the first planetary gear-set that is not directly and continuously connected to one of the plurality of nodes of the second planetary gear-set.

The second torque-transmitting device may be configured to selectively connect the second power source to the node of the second planetary gear-set selectively connected to the transmission housing via the first torque-transmitting device.

The second power source may be operatively connected to one of the plurality of nodes of the first planetary gear-set that is not directly and continuously connected to one of the plurality of nodes of the second planetary gear-set.

The first and the second power sources may be directly and continuously connected to separate nodes of the first planetary gear-set. In such an embodiment, the transmission assembly may also include a third torque-transmitting device configured to selectively connect two nodes of the first planetary gear-set individually and continuously connected to the respective first and the second power sources.

The transmission assembly may also include a fourth torque-transmitting device configured to selectively connect the second power source to the first planetary gear-set.

The transmission assembly may also include a fifth torque-transmitting device configured to selectively connect the first power source to the directly and continuously connected nodes of the first planetary gear-set and the second planetary gear-set.

The second planetary gear-set may be configured as a Ravigneaux planetary gear-set. In such an embodiment, the transmission assembly may also include a sixth torque-transmitting device configured to selectively ground to the transmission housing a node of the Ravigneaux second planetary gear-set not selectively connected to the transmission housing by the first torque-transmitting device.

The first planetary gear-set may be configured as a Ravigneaux planetary gear-set. In such an embodiment, the transmission assembly may also include a seventh torque-transmitting device configured to selectively connect two separate nodes of the Ravigneaux first planetary gear-set not operatively connected to either the first power source or the second power source.

The transmission assembly may also include an eighth torque-transmitting device configured to selectively ground to the transmission housing a node of the Ravigneaux first planetary gear-set not operatively connected to either the first power source or the second power source and not directly and continuously connected to one of the plurality of nodes of the second planetary gear-set.

The first power source may be an electric motor-generator, while the second power source may be an internal combustion engine.

The motor vehicle may be arranged along a longitudinal vehicle axis and may include a final drive assembly. Each of the first power source, second power source, and the final drive assembly may be arranged along the longitudinal vehicle axis or along respective axes arranged transverse to the longitudinal vehicle axis.

A motor vehicle employing such a powertrain operatively connected via a final drive assembly to first and second road wheels is also disclosed.

DETAILED DESCRIPTION

Referring to the drawings in which like elements are identified with identical numerals throughout,FIG. 1illustrates a vehicle10having independent first and second power sources that may be operatively connected to respective sets of driven wheels in order to provide on-demand all-wheel-drive propulsion. The vehicle10may include, but not be limited to, a commercial vehicle, industrial vehicle, passenger vehicle, aircraft, watercraft, train or the like. As shown inFIG. 1, the vehicle10is generally arranged along a longitudinal vehicle axis X. The vehicle10includes a first drive axle12, which may be one of a plurality of drive axles employed in the vehicle. The drive axle12includes a powertrain13. The powertrain13includes a first power source14, which may be an electric motor-generator, as shown. The powertrain13also includes a second power source16, which may be an internal combustion engine, as shown, and thus be configured as a power-split hybrid-electric drive axle.

In the powertrain13with the first and second power sources14,16configured as the respective first electric motor-generator and the internal combustion engine, the drive axle12is configured as a power-split hybrid-electric drive axle, and the powertrain13is a hybrid powertrain. The drive axle12also includes a transmission assembly18, along with a first set of wheels, including a first or left-side road wheel20-1operatively connected to transmission assembly via a first axle-shaft22-1and a second or right-side road wheel20-2operatively connected to the transmission assembly via a second axle-shaft22-2. The drive axle12also includes a final drive assembly23operatively connected to and configured to distribute torque transmitted by the transmission assembly18to each of the first and second road wheels20-1,20-2. Each of the first power source14, second power source16, and the final drive assembly23may be arranged along the longitudinal vehicle axis X (shown inFIG. 1) or along respective axes Y1, Y2, and Y3(shown inFIG. 2) arranged transverse to the longitudinal vehicle axis X.

The first power source14and the second power source16are configured to drive the vehicle10through the transmission assembly18, either together or separately, via the final drive assembly23and the first and second wheels20-1,20-2. Specifically, the first power source14is configured to generate a first torque output T1, while the second power source16is configured to generate a second torque output T2, each for driving the vehicle through the transmission assembly18. The transmission assembly18generally includes a first transmission input member24-1configured to receive torque of the first and second power sources14,16, and a transmission output member26configured to transmit torque from the transmission assembly to the first and second axle-shafts22-1,22-2via a final drive assembly23. The transmission assembly18includes a plurality of torque-transmitting devices, specifically a first torque-transmitting device42-1and a second torque-transmitting device42-2, as described in detail below. Additionally, the plurality of torque-transmitting devices may include third, fourth, fifth, and sixth torque-transmitting devices42-3,42-4,42-5,42-6, as is also described below.

As shown inFIGS. 1 and 2, the vehicle10additionally includes a second drive axle28. The second drive axle28is operatively independent from the first drive axle12. The second drive axle28includes a third power source30, shown as a second electric motor-generator that is configured to generate a third torque output T3for driving the vehicle10via a second set of wheels, which includes a first or left-side road wheel32-1and a second or right-side road wheel32-2. Each of the first, second, and third power sources14,16,30configured as respective electric motor-generators receives its electrical energy from an energy storage device34. Accordingly, the vehicle10may be powered by the respective first and second vehicle drive axles12and28independently or in combination to generate on-demand front, rear, or all-wheel-drive propulsion. Additionally, the first and second drive axles12,28may be arranged such that the first drive axle is positioned at the front of the vehicle10and the second drive axle is positioned at the rear of the vehicle, or vice versa.

Specific embodiments of the first drive axle12with the powertrain13using the transmission assembly18are represented in lever diagram form inFIGS. 3-9. A lever diagram is a schematic representation of the components of a mechanical device such as an automatic transmission. Each individual lever represents a planetary gear-set or an external gear-set. In the planetary gear-set levers, the three basic mechanical components of the planetary gear are each represented by a node. Therefore, a single planetary gear-set lever contains three nodes: one for the sun gear member, one for the planet gear carrier member, and one for the ring gear member. The relative length between the nodes of each planetary gear-set lever may be used to represent the ring-to-sun ratio of each respective gear-set. These lever ratios, in turn, are used to vary the gear ratios of the transmission in order to achieve appropriate ratios and ratio progression. Mechanical couplings or interconnections between the nodes of the various planetary gear-sets are illustrated by thin, solid lines and torque-transmitting devices such as clutches and brakes are presented as interleaved fingers. If the subject torque-transmitting device is a brake, one set of the fingers is grounded. Further explanation of the format, purpose and use of lever diagrams may be found in SAE Paper 810102, authored by Benford, Howard and Leising, Maurice, “The Lever Analogy: A New Tool in Transmission Analysis”, 1981, which is hereby fully incorporated by reference.

The transmission assembly18includes a first planetary gear-set36having a plurality of nodes, shown inFIGS. 3-8as a first node A, a second node B, and a third node C. The nodes A, B, and C represent a first, second and third members of the planetary gear-set36, such as a ring gear member, a carrier member rotatably supporting a plurality of pinion gears, and a sun gear member, although not necessarily in that order. An alternative embodiment of the first planetary gear-set36is a Ravigneaux gear-set having four nodes, specifically nodes A, A′, B, and C, as shown inFIG. 9. The nodes A, A′, B, and C represent a first, second, third, and fourth members of the planetary gear-set136, such as a first and second sun gear members, a carrier member, and a ring gear member, although not necessarily in that order.

Each of the above-discussed embodiments of the first planetary gear-set36is operatively and continuously connected to the first transmission input member24-1. The transmission assembly18also includes a second planetary gear-set38having a plurality of nodes shown inFIGS. 3-5, 7, and 9as a first node D, a second node E, and a third node F. An alternative embodiment of the second planetary gear-set38is a Ravigneaux gear-set having four nodes, specifically nodes D, E, F, and F′, as shown inFIGS. 6 and 7. Each of the above-discussed embodiments of the second planetary gear-set38is operatively and continuously connected to the transmission output member26.

In general, the Ravigneaux planetary gear-set is constructed from two meshed gear pairs—a ring gear member/planetary gear pair and a planetary gear/sun gear pair. A Ravigneaux planetary gear-set may have two sun gears members—a large sun gear and a small sun gear. Alternatively, a Ravigneaux planetary gear-set may have two separate ring gears. A Ravigneaux planetary gear-set has a single planet carrier member holding two sets of planetary gears—inner planetary gears and outer planetary gears. The planet carrier member is a single sub-assembly that supports the inner and outer planetary gears on distinct, respective inner and outer pitch circles. The two sets of planetary gears are in mesh and therefore co-rotate with a fixed gear ratio with respect to each other, but independently of the carrier. In the embodiment employing two sun gear members, the inner planetary gears couple with the small sun gear and co-rotate at a fixed gear ratio with respect thereto, while the outer planetary gears couple with the large sun gear and co-rotate with a fixed gear ratio with respect thereto. In the embodiment employing two ring gear members, one ring gear member may mesh with the outer planetary gears and co-rotate with the subject outer planetary gears in a fixed gear ratio, while another ring gear member may mesh with the inner planetary gears and co-rotate with the subject inner planetary gears in a fixed gear ratio.

For example, in a particular embodiment of the Ravigneaux first gear-set36shown inFIG. 9, the nodes A, A′, B, and C represent a first, second, third, and fourth members—specifically a first sun gear member336-1, a second sun gear member336-1′, a carrier member336-2, and a ring gear member336-3, respectively. Furthermore, in a particular embodiment of the Ravigneaux second gear-set38shown inFIGS. 6 and 7, the nodes D, E, F, and F′ represent a first, second, third, and fourth members—specifically a sun gear member238-1, a carrier member238-2, a first ring gear member238-3, and, a second ring gear member238-3′, respectively.

The transmission assembly18additionally includes a transmission housing40configured to encase and retain the first and second planetary gear-sets36,38. The transmission housing40may be mounted to each of and in between the first and second power sources14,16. As noted above, the transmission assembly18also includes the first torque-transmitting device42-1. The first torque-transmitting device42-1is configured to selectively connect or ground one of the plurality of nodes D, E, F of the second planetary gear-set38to the transmission housing40. Specifically, as shown in the embodiments ofFIGS. 3-9, the first torque-transmitting device42-1may be configured to selectively connect or ground the node F to the transmission housing40.

As noted above, the transmission assembly18further includes the second torque-transmitting device42-2. The second torque-transmitting device42-2is configured to selectively connect one of the plurality of nodes A, B, C of the first planetary gear-set36to one of the plurality of nodes D, E, F of the second planetary gear-set38. Specifically, as shown in the embodiments ofFIGS. 3, 6, and 8, the second torque-transmitting device42-2may be configured to selectively connect the node C to the node F; as shown in the embodiment ofFIG. 4, the second torque-transmitting device42-2may be configured to selectively connect the node B to the node F; as shown inFIG. 5, the second torque-transmitting device42-2may be configured to selectively connect the node A to the node F. Additionally, in the embodiment ofFIG. 9depicting the Ravigneaux first planetary gear-set136, the second torque-transmitting device42-2may be configured to selectively connect the node A′ to the node F. Furthermore, in the embodiment ofFIG. 7depicting the Ravigneaux second planetary gear-set138, the second torque-transmitting device42-2may be configured to selectively connect the node C to the node F′.

One of the plurality of nodes A, B, C of the first planetary gear-set36is directly and continuously connected to one of the plurality of nodes D, E, F of the second planetary gear-set38. Specifically, as shown in the embodiment ofFIG. 3, the second node B may be directly and continuously connected to the first node D; as shown in the embodiment ofFIG. 4, the third node C may be directly and continuously connected to the first node D; and as shown in the embodiments ofFIG. 5-9, the second node B may be directly and continuously connected to the first node D. The first power source14is operatively connected to one of the plurality of nodes A, B, C of the first planetary gear-set36that is not directly and continuously connected to one of the plurality of nodes D, E, F of the second planetary gear-set38. The powertrain13also includes a second input member24-2, such that the second power source16is then operatively connected via the second input member to one of the plurality of nodes A, B, C of the first planetary gear-set36.

As shown in the embodiments ofFIGS. 3-9, the second power source16may be operatively connected to one of the plurality of nodes A, B, C of the first planetary gear-set36that is not directly and continuously connected to one of the plurality of nodes D, E, F of the second planetary gear-set38. Specifically, as shown inFIGS. 3, 6, 7, and8, the second power source16may be continuously connected via the second input member24-2to the node C. Additionally, as shown in the embodiment ofFIG. 4, the second power source16may be continuously connected via the second input member24-2to the node B, or, as shown in the embodiment ofFIG. 5, the second power source16may be continuously connected via the second input member24-2to the node A. In the embodiments of the power-split hybrid-electric drive axle12shown inFIGS. 3-7 and 8, the first and the second power sources14,16may be directly and continuously connected to separate nodes of the first planetary gear-set36. Furthermore, in the embodiments depicted inFIGS. 3, 4, 6, and 7, the transmission assembly18additionally includes a third torque-transmitting device42-3. As shown, the third torque-transmitting device42-3is configured to selectively connect two nodes of the first planetary gear-set36that are directly, individually, and continuously connected to the respective first and second power sources14,16. Specifically, inFIGS. 3, 6, and 7the third torque-transmitting device42-3selectively connects the node A to the node C. Alternatively, as shown inFIG. 4, the third torque-transmitting device42-3selectively connects the node A to the node B.

In a yet another embodiment, the transmission18may include a fourth torque-transmitting device42-4configured to selectively connect the second power source16to the first planetary gear-set36. Specifically, as shown inFIG. 8, the fourth torque-transmitting device42-4may be configured to selectively connect the second power source16to the node C. As shown inFIGS. 5 and 8, an embodiment of the power-split hybrid-electric drive axle12may additionally include a fifth torque-transmitting device42-5. The fifth torque-transmitting device42-5is configured to selectively connect the first power source14to the directly and continuously connected nodes of the first planetary gear-set36and the second planetary gear-set38. Specifically, the fifth torque-transmitting device42-5may be configured to selectively connect the first power source14to the directly and continuously interconnected nodes B and D.

As shown inFIGS. 6 and 8, an embodiment of the power-split hybrid-electric drive axle12may additionally include a sixth torque-transmitting device42-6. The sixth torque-transmitting device42-6is configured to selectively ground to the transmission housing40a node of the Ravigneaux second planetary gear-set138not selectively connected to the transmission housing by the first torque-transmitting device42-1. Specifically, the sixth torque-transmitting device42-6may be configured to selectively ground the node F′ of the Ravigneaux second planetary gear-set138to the transmission housing40.

As shown inFIG. 9, an embodiment of the power-split hybrid-electric drive axle12may additionally include a seventh torque-transmitting device42-7. The seventh torque-transmitting device42-7is configured to selectively connect two separate nodes of the Ravigneaux first planetary gear-set136not operatively connected to either the first power source14or the second power source16. Specifically, the seventh torque-transmitting device42-7may be configured to selectively connect the node B to the node C of the Ravigneaux first planetary gear-set136. As additionally shown inFIG. 9, the power-split hybrid-electric drive axle12may further include an eighth torque-transmitting device42-8. The eighth torque-transmitting device42-8is configured to selectively ground to the transmission housing40a node of the Ravigneaux first planetary gear-set136not operatively connected to either the first power source14or the second power source16. Furthermore, the eighth torque-transmitting device42-8is configured to selectively ground to the transmission housing40a node of the Ravigneaux first planetary gear-set136not directly and continuously connected to one of the plurality of nodes of the second planetary gear-set138. Specifically, the eighth torque-transmitting device42-8may be configured to selectively ground the node C of the Ravigneaux first planetary gear-set136to the transmission housing40.

In each of the above embodiments, the third, fifth, and seventh torque-transmitting devices42-3,42-5,42-7are configured to operate as a lock-up clutches to enable fixed gear operation in the transmission assembly18. The sixth and eighth torque-transmitting devices42-6,42-8are configured to operate as reverse clutches to enable the output member26to rotate in an opposite direction as compared to the direction of rotation of the second power source16.

InFIG. 3A, the powertrain13is represented by a schematic stick diagram that depicts specific planetary gear-set connections corresponding to and reflected by the lever diagram ofFIG. 3. The exemplary embodiment of the transmission assembly18represented by the lever diagram inFIG. 3is identified inFIG. 3Awith a numeral18-1. The transmission assembly embodiment18-1has a specific embodiment of the first planetary gear-set36, identified with a numeral136, and a specific embodiment of the second planetary gear-set38, identified with a numeral138. The first planetary gear-set136employs a sun gear member136-1which is circumscribed by a ring gear member136-3, and a carrier member136-2rotatably supporting a plurality of pinion gears that meshingly engage both the sun gear member136-1and the ring gear member136-3. The second planetary gear-set138employs a sun gear member138-1which is circumscribed by a ring gear member138-3, and a carrier member138-2rotatably supporting a set of pinion gears. The set of pinion gears meshingly engages the sun gear member138-1and the ring gear member138-3.

The exemplary transmission assembly embodiment18-1is configured such that the first power source14, which is shown as an electric motor-generator is continuously connected via the first input member24-1to the node A, which is specifically shown as the sun gear member136-1. The node B, which is specifically shown as the carrier member136-2, is continuously connected to the node D, which is specifically shown as the sun gear member138-1. The node C, which is specifically shown as the ring gear member136-3, is selectively connected to the node F, which is specifically shown as the ring gear member138-3, via the second torque-transmitting device42-2. The ring gear member138-3at the node F is also selectively connected via the first torque-transmitting device42-1to the transmission housing40. The second power source16, which is shown as an internal combustion engine, is continuously connected via the second input member24-2and a torsional damper25to the ring gear member136-3at the node C. The node C is also selectively connected via the third torque-transmitting device42-3to the node A. The node E, which is specifically shown as the carrier member138-2, is continuously connected to the final drive assembly23via the transmission output member26and through the torque transfer mechanism23A.

InFIG. 6A, the powertrain13is represented by a schematic stick diagram that depicts specific planetary gear-set connections corresponding to and reflected by the lever diagram ofFIG. 6. The exemplary embodiment of the transmission assembly18represented by the lever diagram inFIG. 6is identified inFIG. 6Awith a numeral18-2. The transmission assembly embodiment18-2has a specific embodiment of the first planetary gear-set36, identified with a numeral236, and a specific embodiment of the Ravigneaux second planetary gear-set38, identified with a numeral238. The first planetary gear-set236employs a sun gear member236-1which is circumscribed by a ring gear member236-3, and a carrier member236-2rotatably supporting a plurality of pinion gears that meshingly engage both the sun gear member236-1and the ring gear member236-3. The second planetary gear-set238employs a sun gear member238-1which is circumscribed by a first ring gear member238-3and a second ring gear member238-3′, and a carrier member238-2rotatably supporting two sets of pinion gears. One of the sets of pinion gears meshingly engages the sun gear member238-1and the first ring gear member238-3, while the other set of pinion gears meshingly engages the second ring gear member238-3′.

The exemplary transmission assembly embodiment18-2is configured such that the first power source14, which is shown as an electric motor-generator is continuously connected via the first input member24-1to the node A, which is specifically shown as the sun gear member236-1. The node B, which is specifically shown as the carrier member236-2, is continuously connected to the node D, which is specifically shown as the sun gear member238-1. The node C, which is specifically shown as the ring gear member236-3, is selectively connected to the node F, which is specifically shown as the ring gear member238-3, via the second torque-transmitting device42-2. The ring gear member238-3at the node F is also selectively connected via the first torque-transmitting device42-1to the transmission housing40. The second power source16, which is shown as an internal combustion engine, is continuously connected via the second input member24-2and the torsional damper25to the ring gear member236-3at the node C. The node C is also selectively connected via the third torque-transmitting device42-3to the node A. The node E, which is specifically shown as the carrier member238-2, is continuously connected to the final drive assembly23via the transmission output member26and through the torque transfer mechanism23A. The node F′, which is specifically shown as the ring gear member238-3′, is selectively connected to the transmission housing40via the eighth torque-transmitting device42-8.

InFIG. 9A, the powertrain13is represented by a schematic stick diagram that depicts specific planetary gear-set connections corresponding to and reflected by the lever diagram ofFIG. 9. The exemplary embodiment of the transmission assembly18represented by the lever diagram inFIG. 9is identified inFIG. 9Awith a numeral18-3. The transmission assembly embodiment18-3has a specific embodiment of the Ravigneaux first planetary gear-set36, identified with a numeral336, and a specific embodiment of the second planetary gear-set38, identified with a numeral338. The first planetary gear-set336employs a sun gear member336-1which is circumscribed by a first ring gear member336-3. The first planetary gear-set336also employs a second sun gear member336-1′ and a carrier member336-2rotatably supporting two sets of pinion gears. One of the sets of pinion gears meshingly engages the first sun gear member336-1and the first ring gear member336-3, while the other set of pinion gears meshingly engages the second sun gear member336-1′. The second planetary gear-set338employs a sun gear member338-1which is circumscribed by a ring gear member338-3, and a carrier member338-2rotatably supporting a set of pinion gears. The set of pinion gears meshingly engages the sun gear member338-1and the ring gear member338-3.

The exemplary transmission assembly embodiment18-3is configured such that the first power source14, which is shown as an electric motor-generator is continuously connected via the first input member24-1to the node A, which is specifically shown as the first sun gear member336-1. The node B, which is specifically shown as the carrier member336-2, is continuously connected to the node D, which is specifically shown as the sun gear member338-1. The node A′, which is specifically shown as the second sun gear member336-1′, is selectively connected to the node F, which is specifically shown as the ring gear member338-3, via the second torque-transmitting device42-2. The node C, which is specifically shown as the ring gear member336-3, is selectively connected to the carrier member336-2at node B via the seventh torque-transmitting device42-7. The ring gear member338-3at the node F is also selectively connected via the eighth torque-transmitting device42-8to the transmission housing40. The second power source16, which is shown as an internal combustion engine, is continuously connected via the second input member24-2and a torsional damper25to the second sun gear member336-1′ at the node A′. The carrier member336-2at node B is continuously connected to the sun gear member338-1at the node D. The node E, which is specifically shown as a carrier member338-2, is continuously connected to the final drive assembly23via the transmission output member26and through the torque transfer mechanism23A.

Overall, each of the above embodiments of the powertrain13permits use of a single power source14coupled to the transmission assembly18employing a minimal number of gear sets and torque transmitting devices for powering the vehicle10at the first drive axle12. A lock-up clutch is employed by the transmission assembly18to enable fixed gear operation therein. Additionally, the transmission assembly18may employ an input brake to permit electric propulsion of the vehicle10via the first power source14, i.e., without torque input from the second power source16. The disclosed embodiments of the transmission assembly18coupled with the first power source14and the second power source16provide a low-complexity, efficiently packaged powertrain for an electric or a hybrid-electric motor vehicle. Additionally, such embodiments of the powertrain13and the transmission18may be used either in front-wheel-drive or all-wheel drive vehicle configurations.