MOTOR VEHICLE HYBRID POWERTRAIN
20210107348 · 2021-04-15
Assignee
Inventors
- Neeraj S. Shidore (Novi, MI)
- Derek F. Lahr (Howell, MI, US)
- Lei Hao (Troy, MI)
- Madhusudan Raghavan (West Bloomfield, MI, US)
- Suresh Gopalakrishnan (Troy, MI)
Cpc classification
B60K6/387
PERFORMING OPERATIONS; TRANSPORTING
B60K2006/4825
PERFORMING OPERATIONS; TRANSPORTING
B60K6/547
PERFORMING OPERATIONS; TRANSPORTING
B60K6/26
PERFORMING OPERATIONS; TRANSPORTING
B60K6/54
PERFORMING OPERATIONS; TRANSPORTING
F16H9/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H2200/0021
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H1/28
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
B60K6/24
PERFORMING OPERATIONS; TRANSPORTING
B60K6/383
PERFORMING OPERATIONS; TRANSPORTING
B60K2006/381
PERFORMING OPERATIONS; TRANSPORTING
H02K7/006
ELECTRICITY
B60K2006/268
PERFORMING OPERATIONS; TRANSPORTING
B60K2006/262
PERFORMING OPERATIONS; TRANSPORTING
B60K2006/4833
PERFORMING OPERATIONS; TRANSPORTING
H02K11/0094
ELECTRICITY
H02K11/05
ELECTRICITY
International classification
B60K6/54
PERFORMING OPERATIONS; TRANSPORTING
B60K6/26
PERFORMING OPERATIONS; TRANSPORTING
B60K6/383
PERFORMING OPERATIONS; TRANSPORTING
B60K6/387
PERFORMING OPERATIONS; TRANSPORTING
F16H1/28
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H9/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
H02K11/00
ELECTRICITY
H02K13/00
ELECTRICITY
H02K7/00
ELECTRICITY
Abstract
A vehicle powertrain includes a first power-source configured to generate a first power-source torque and a multiple speed-ratio transmission configured to transmit the first power-source torque to power the vehicle. The powertrain also includes a fluid coupling having a fluid pump shaft operatively connected to the first power-source and a turbine shaft operatively connected to the multi-speed transmission. The fluid coupling is configured to multiply the first power-source torque, and transfer the multiplied first power-source torque to the multiple speed-ratio transmission. The powertrain additionally includes a second power-source configured to generate a second power-source torque and a first torque transfer system configured to connect the second power-source to the first power-source. The powertrain further includes a second torque transfer system configured to connect the second power-source to the multi-speed transmission. A motor vehicle having such a powertrain is also envisioned.
Claims
1. A powertrain for powering a vehicle, the powertrain comprising: a first power-source configured to generate a first power-source torque; a multiple speed-ratio transmission configured to transmit the first power-source torque to power the vehicle; a fluid coupling having a fluid pump shaft operatively connected to the first power-source and a turbine shaft operatively connected to the multiple speed-ratio transmission, multiply the first power-source torque, and transfer the multiplied first power-source torque to the multiple speed-ratio transmission; a second power-source configured to generate a second power-source torque; a first torque transfer system configured to connect the second power-source to the first power-source; and a second torque transfer system configured to connect the second power-source to the multiple speed-ratio transmission.
2. The powertrain according to claim 1, wherein each of the first torque transfer system and the second torque transfer system is a gear-set or a chain mechanism.
3. The powertrain according to claim 1, wherein: the multiple speed-ratio transmission includes an input shaft; each of the first power-source, the fluid coupling, and the input shaft is arranged on a first rotational axis; the second power-source is arranged on a second rotational axis; and the second rotational axis is arranged parallel to first rotational axis.
4. The powertrain according to claim 3, wherein the first power-source is an internal combustion engine, and wherein the second power-source is an electric motor housed inside a motor housing, the electric motor including: a rotor free to rotate relative to the motor housing and having a rotor shaft operatively connected to the first torque transfer system; and a stator having a stator shaft operatively connected to the second torque transfer system.
5. The powertrain according to claim 4, wherein the multiple speed-ratio transmission includes a transmission case configured to mount the multiple speed-ratio transmission to the first power-source, the powertrain further comprising a first torque-transmitting device configured to selectively couple the stator to the transmission case.
6. The powertrain according to claim 5, wherein the stator shaft includes a disc element extending radially therefrom, and wherein the first torque-transmitting device is configured to selectively couple the disc element to the transmission case.
7. The powertrain according to claim 5, further comprising a second torque-transmitting device configured to selectively connect the stator shaft to the second torque transfer system.
8. The powertrain according to claim 7, wherein the second torque-transmitting device is a multiple-plate friction clutch or a one-way clutch.
9. The powertrain according to claim 7, wherein the vehicle includes an energy storage device configured to generate and store electrical power for the first and second power-sources, the powertrain further comprising a rectifier configured to convert alternating current (AC) to direct current (DC) and slip rings configured transfer electrical current to and from the stator.
10. The powertrain according to claim 9, wherein: each of the stator and the rectifier is housed inside the motor housing, and the slip rings transfer the DC current to the energy storage device; or the rectifier is arranged externally to the motor housing, and the slip rings transfer the AC current to the rectifier for charging the energy storage device.
11. A motor vehicle comprising: a vehicle powertrain including: a first power-source configured to generate a first power-source torque; a multiple speed-ratio transmission having an output member and configured to transmit the first power-source torque to power the motor vehicle; a fluid coupling having a fluid pump shaft operatively connected to the first power-source and a turbine shaft operatively connected to the multiple speed-ratio transmission, multiply the first power-source torque, and transfer the multiplied first power-source torque to the multiple speed-ratio transmission; a second power-source configured to generate a second power-source torque; an energy storage device configured to generate and store electrical power for the first and second power-sources; a first torque transfer system configured to connect the second power-source to the first power-source; and a second torque transfer system configured to connect the second power-source to the multiple speed-ratio transmission; and a road wheel operatively connected to the output member to receive the first power-source torque and/or the second power-source torque transmitted by the multiple speed-ratio transmission.
12. The motor vehicle according to claim 11, wherein each of the first torque transfer system and the second torque transfer system is a gear-set or a chain mechanism.
13. The motor vehicle according to claim 11, wherein: the multiple speed-ratio transmission includes an input shaft; each of the first power-source, the fluid coupling, and the multiple speed-ratio transmission input shaft is arranged on a first rotational axis; the second power-source is arranged on a second rotational axis; and the second rotational axis is arranged parallel to first rotational axis.
14. The motor vehicle according to claim 13, wherein the first power-source is an internal combustion engine, and wherein the second power-source is an electric motor housed inside a motor housing, the electric motor including: a rotor free to rotate relative to the motor housing and having a rotor shaft operatively connected to the first torque transfer system; and a stator having a stator shaft operatively connected to the second torque transfer system.
15. The motor vehicle according to claim 14, wherein the multiple speed-ratio transmission includes a transmission case configured to mount the multiple speed-ratio transmission to the first power-source, wherein the vehicle powertrain additionally includes a first torque-transmitting device configured to selectively couple the stator to the transmission case.
16. The motor vehicle according to claim 15, wherein the stator shaft includes a disc element extending radially therefrom, and wherein the first torque-transmitting device is configured to selectively couple the disc element to the transmission case.
17. The motor vehicle according to claim 15, wherein the vehicle powertrain additionally includes a second torque-transmitting device configured to selectively connect the stator shaft to the second torque transfer system.
18. The motor vehicle according to claim 17, wherein the second torque-transmitting device is a multiple-plate friction clutch or a one-way clutch.
19. The motor vehicle according to claim 17, further comprising a rectifier configured to convert alternating current (AC) to direct current (DC) and slip rings configured transfer electrical current to and from the stator.
20. The motor vehicle according to claim 19, wherein: each of the stator and the rectifier is housed inside the motor housing, and wherein the slip rings transfer the DC current to the energy storage device; or the rectifier is arranged externally to the motor housing, and the slip rings transfer the AC current to the rectifier for charging the energy storage device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0019]
[0020]
[0021]
[0022]
[0023]
DETAILED DESCRIPTION
[0024] Referring to
[0025] The powertrain 12 includes a first power-source 14 configured to generate a first power-source torque T.sub.i (shown in
[0026] In some vehicle configurations, the powertrain 12 may be mounted longitudinally in the vehicle 10, i.e., substantially aligned with the longitudinal axis X of the vehicle. In other vehicle configurations, the powertrain 12 may be mounted transversely in the vehicle 10, i.e., at approximately 90 degrees relative to the longitudinal axis X of the vehicle. Such a transverse mounting of the powertrain 12 is frequently employed for packaging purposes in front-wheel-drive (FWD) vehicles, where the drive wheel(s) 16 are arranged proximate a front end of the vehicle 10. In such vehicle configurations, the transmission 20 may be combined with a final drive assembly and is generally described as a transaxle. Although the longitudinal transmission embodiment of the transmission 20 is specifically referred to below, the disclosure is also applicable to transaxle configurations of the transmission 20.
[0027] The transmission 20 is operatively connected to the first power-source 14, i.e., externally mounted to the first power-source and configured to transfer the first power-source torque T.sub.i to the driven wheels 16. The transmission 20 is further configured to receive and then selectively multiply, reduce, or leave unmodified the first power-source torque T.sub.i to achieve a resultant transmission output torque T.sub.o (shown in
[0028] The first power-source 14 may be an internal combustion engine, a fuel-cell, and/or an electric motor (not shown) mounted in the vehicle 10 and having the transmission 20 mounted externally thereto. However, for conciseness and clarity, the present disclosure will concentrate on the internal combustion engine embodiment of the first power-source 14. Accordingly, although the numeral 14 should be seen as generally attributable to such embodiments of the envisioned powertrain, for the remainder of the present disclosure, the numeral 14 will be used to denote the specific embodiment of the powertrain having solely the internal combustion engine. As such, the first power-source torque T.sub.i will be hereinafter also referenced as engine 14 torque. As shown, the particular engine 14 may include a crankshaft 14-1 arranged on the first rotational axis A1 for converting reciprocal motion of its pistons 14-2 into rotational motion and generating the engine 14 torque. The vehicle 10 also includes an energy storage device 26, such as one or more batteries, configured to supply electrical power to the powertrain 12, and specifically the first power-source 14 and various electronically controlled components of the transmission 20.
[0029] As shown in
[0030] The transmission's torque path 32 may also include one or more torque transmitting devices 34B, such as clutches and brakes, retained by the transmission housing 30. The torque transmitting devices 34B are generally cooperatively configured to select transmission speed-ratios and facilitate generation of a predetermined amount of transmission output torque T.sub.o. A transmission speed-ratio is generally defined as the transmission input speed divided by the transmission output speed. Shifting from one speed-ratio to another is typically performed in response to a position of the vehicle accelerator 24 and assessed vehicle road speed. Shifting between speed-ratios generally involves releasing one or more “off-going” torque transmitting devices 34B associated with the current speed ratio, and applying one or more “on-coming” torque transmitting devices 34B associated with the desired speed-ratio.
[0031] Alternatively, the transmission 20 may be configured as a continuously variable speed ratio transmission (CVT), wherein the transmission's torque path 32 may include a variable diameter pulley system 34C (shown in
[0032] In each of the embodiments shown in
[0033] As shown in each of
[0034] As shown in
[0035] The engine 14 and the electric motor 44 may be operatively connected to the transmission torque path 32 at the input member 36. Accordingly, the transmission 20 is configured to receive the first power-source torque T.sub.i and the electric motor torque T.sub.e and output a sum of the first power-source and the electric motor torques to drive a load, e.g., the driven road wheels 16. As shown, the electric motor 44 is arranged on and configured to operate with respect to a second rotational axis A2 that is parallel to the first axis A1. As shown in
[0036] The powertrain 12 also includes a first torque transfer system 52 configured to connect the second power-source 44 to the fluid coupling 40. The first torque transfer system 52 is specifically configured to transfer the second power-source torque T.sub.e from the rotor 50 to the fluid pump shaft 40-1, and thus add the second power-source torque T.sub.e to the first power-source torque T.sub.i. The first torque transfer system 52 and the second torque transfer system may be configured as a gear-set (shown in
[0037] The powertrain 12 may additionally include a first torque-transmitting device 56. The first torque-transmitting device 56 may be configured as a friction brake to selectively couple the stator 48, i.e., engage to or disengage from, the transmission case 30. The stator shaft 48-1 may include a disc element 58 extending radially therefrom. The first torque-transmitting device 56 may then be configured to selectively couple the disc element 58 to the transmission case 30. The powertrain 12 may further include a second torque-transmitting device 60. The second torque-transmitting device 60 may be configured to selectively connect the stator shaft 48-1 to the second gear-set 54. The second torque-transmitting device 60 may be configured as a multiple-plate friction clutch (shown in
[0038] The powertrain 12 may also include slip rings 64 configured to transfer electrical power to and from the stator 48. In other words, the slip rings 64 may exchange power between the rectifier 62 and the energy storage device 26, or between the stator 26 and the rectifier. In an embodiment where the rectifier 62 is arranged inside the motor housing 46, such as on the stator shaft 48-1, the slip rings 64 may extract DC current from the stator 48 to the energy storage device 26. Alternatively, in an embodiment where the rectifier 62 is grounded to or arranged external to the transmission housing 30, the stator 48, the slip rings 64 may transfer AC current to such an external rectifier, which may in turn convert the AC current to DC current and then charge the energy storage device 26. Alternatively, such a uni-directional rectifier 62, which converts AC current to DC current, may be replaced by a bi-directional device, e.g., an inverter (not shown) which may transfer electrical energy from the energy storage device 26 to the second power-source 44, for motoring action. As shown in
[0039] Overall, the powertrain 12 is configured to generate electrical energy, i.e., the second power-source torque T.sub.e, across the fluid coupling 40, while reducing losses through the fluid coupling. The powertrain 12 may employ an engine 14 with cylinder deactivation or similar technology, where in a certain fraction of engine's cylinders is deactivated based on engine load. In such a powertrain 12, the slip of the torque converter 40 is normally configured to account for the change in engine torsional vibrations due to a varied number of firing cylinders. Because the second power-source 44 provides a bypass for the torque through torque converter 40, the robustness of slip control in the torque converter 40 may be enhanced by assistance from the second power source 44. For example, the amount of torque transferred through torque converter 40 may be reduced, as compared to a powertrain architecture without the second power source 44. As a result, the force required to provide specific engagement of the torque converter clutch 40-3 sufficient to maintain a certain amount of slip inside the torque converter 40, may also be reduced. The second power-source 44 may also be employed to provide the vehicle 10 with hybrid propulsion. The second power-source 44 may be additionally employed to facilitate control of the slip in the torque converter 40 during cylinder deactivation modes of the subject engine 14 during speed-ratio shifts in the transmission 20 via the gear-train 34A and the torque transmitting devices 34B.
[0040] The powertrain 12 may operate in stop-start mode when either the first torque-transmitting device 56 or the second torque-transmitting device 60 is engaged. Specifically, in such a stop-start mode, the electric motor 44 may be employed as an alternator-starter for the engine 14. When the torque converter clutch 40-3 is open or slipping at low differential speed and the second torque-transmitting device 60 is engaged, the electric motor 44 may be employed as a generator across the fluid coupling 40, reduce losses across the fluid coupling, and provide a bypass for the second power-source torque T.sub.e to the transmission's torque path 32, i.e., effectively circumventing the fluid coupling.
[0041] When the torque converter clutch 40-3 is open, slipping at low differential speed, or locked, and the first torque-transmitting device 56 is engaged, the powertrain 12 may operate in generator mode, wherein at least some of the first power-source torque T.sub.i is used to drive the electric motor 44. Additionally, when the torque converter clutch 40-3 is open and the first torque-transmitting device 56 is engaged, the second power-source torque T.sub.e may be used to crank the engine 14 in the stop-start mode. Furthermore, when the torque converter clutch 40-3 is open, the powertrain 12 may operate in one of two motoring modes. For example, when the first torque-transmitting device 56 is engaged and the second torque-transmitting device 60 is disengaged, the electric motor 44 may be used to assist the engine 14 in powering the vehicle 10.
[0042] The powertrain 12 may be controlled by a programmable electronic controller 66 configured to achieve desired propulsion of the vehicle 10 in response to command(s) from an operator of the subject vehicle. Specifically, the controller 66 may be programmed to control the first power-source 14, select transmission 20 speed ratios, regulate operation of the first and second torque-transmitting devices 56, 60, and activate the second power-source 44 to generate a predetermined amount of transmission output torque T.sub.o. The controller 66 may include a central processing unit (CPU) that regulates various functions on the vehicle 10, or be configured as a powertrain control module (PCM) configured to control the entire powertrain 12, or a dedicated transmission control unit (TCU) for controlling solely the transmission 20. Configured as either a CPU or a PCM for the powertrain 12, the controller 66 may be employed to control and coordinate operation of the first power-source 14, the second first power-source 44, and the transmission 20. In either of the above configurations, the controller 66 includes a processor and tangible, non-transitory memory, which includes instructions for operation of the powertrain 12 programmed therein. The memory may be an appropriate recordable medium that participates in providing computer-readable data or process instructions. Such a recordable medium may take many forms, including but not limited to non-volatile media and volatile media.
[0043] Non-volatile media for the controller 66 may include, for example, optical or magnetic disks and other persistent memory. Volatile media may include, for example, dynamic random access memory (DRAM), which may constitute a main memory. Such instructions may be transmitted by one or more transmission medium, including coaxial cables, copper wire and fiber optics, including the wires that comprise a system bus coupled to a processor of a computer. Memory of the controller 66 may also include a flexible disk, hard disk, magnetic tape, another magnetic medium, a CD-ROM, DVD, another optical medium, etc. The controller 66 may be configured or equipped with other required computer hardware, such as a high-speed clock, requisite Analog-to-Digital (A/D) and/or Digital-to-Analog (D/A) circuitry, input/output circuitry and devices (I/O), as well as appropriate signal conditioning and/or buffer circuitry. Algorithms required by the controller 66 or accessible thereby may be stored in the memory and automatically executed to provide the required functionality of the powertrain 12.
[0044] The detailed description and the drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed disclosure have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims. Furthermore, the embodiments shown in the drawings or the characteristics of various embodiments mentioned in the present description are not necessarily to be understood as embodiments independent of each other. Rather, it is possible that each of the characteristics described in one of the examples of an embodiment may be combined with one or a plurality of other desired characteristics from other embodiments, resulting in other embodiments not described in words or by reference to the drawings. Accordingly, such other embodiments fall within the framework of the scope of the appended claims.