DESC:FIELD
The present disclosure relates to the field of mechanical engineering. In particular, the present disclosure relates to the field of vehicles.
BACKGROUND
Hybrid vehicles are vehicles that use two or more distinct power sources to move the vehicle. One of the types of hybrid vehicles is a hybrid electric vehicle (HEV) which involves the use of an internal combustion engine in combination with one or more electric motors.
Conventional, hybrid electric vehicles generally involve the use of many auxiliary elements such as two frictional couplings or alternately, one frictional coupling and another fluid coupling. These frictional couplings or fluid couplings generally have a bulky configuration which requires a large space for installation within the vehicles. Owing to a large configuration, these frictional couplings or fluid couplings are difficult to integrate and assemble, and also result in an increase in the overall mass of the vehicles.
Also, in conventional hybrid electric vehicles one or more electric motors are disposed outside the power train, and hence, require connecting linkages which connect the electric motors to the power train. The increase in the number of the linkages complexifies the positioning and packaging of the electric motors and the associated linkages, thereby leading to an increase in cost.
Further, the conventional hybrid electric vehicles use a short spring integrated damper clutch which does not provide a smooth drive to the vehicles.
Hence, there is a need to alleviate the drawbacks associated with the power train of conventional hybrid electric vehicles.

OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a hybrid power train for vehicles which has a reduced number of elements as compared to the conventional hybrid powertrains.
Still another object of the present disclosure is to provide a hybrid power train for vehicles which has a compact configuration and a reduced mass.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages a hybrid powertrain. The hybrid powertrain comprises an engine and a unidirectional torque transfer coupling that is operatively coupled with the engine and is configured to receive torque generated by the engine and transfer torque to an integrated generator. More specifically, the integrated generator is operatively coupled with the unidirectional torque transfer coupling and configured to selectively receive torque from the unidirectional torque transfer coupling. A hybrid torque multiplier assembly is operatively coupled with the integrated generator and the engine and is configured to be selectively actuated by the integrated generator and/or the engine, wherein in a first mode of operation, when the value of torque generated by the engine exceeds the value of torque generated by the integrated generator and when the rotational speed of the integrated generator equals the rotational speed of the engine, the engine is coupled with the integrated generator, thereby resulting in torque addition thereof to obtain a first driving torque which drives the hybrid torque multiplication assembly. In a second mode of operation, when the rotational speed of the integrated generator exceeds the rotational speed of the engine, the engine is decoupled from the integrated generator, and the integrated generator drives the hybrid torque multiplication assembly.
In an embodiment, the unidirectional torque transfer coupling includes an input element and a first connecting element disposed operatively between the engine and the input element for coupling the engine to the unidirectional torque transfer coupling. A first output element is resiliently coupled with the input element via a damper disposed operatively therebetween. Typically, the damper is a torsion spring. A second output element is selectively connectable to the first output element.
In another embodiment, the hybrid powertrain includes a starting assembly configured to selectively actuate the engine during start up condition. The starting assembly includes a low voltage energy storage device and a first stator in electrical communication with the low voltage energy storage device via a second connecting element. A first rotor is configured to rotate within the first stator, wherein the first rotor is operatively coupled with the input element to provide an initial torque to the engine during start up condition thereof.
In yet another embodiment, the integrated generator includes a second rotor and a third connecting element disposed operatively between the second rotor and the second output element to facilitate a coupling of the second rotor with the second output element. A second stator is disposed around the second rotor and is configured to receive, via a fourth connecting element, an alternating current from a power inverter which is in electrical communication with an energy storage device.
In an embodiment, the hybrid powertrain includes a unidirectional torque transfer device for facilitating selective engagement of a fifth connecting element which is operatively coupled with the second rotor with a sixth connecting element which is disposed operatively between the unidirectional torque transfer device and the hybrid torque multiplication assembly and which drives the hybrid torque multiplication assembly.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWING
A hybrid power train for a vehicle of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a schematic representation of a hybrid power train for a vehicle, in accordance with an embodiment of the present disclosure; and
Figure 2 illustrates a side view of a unidirectional torque transfer clutch of the hybrid power train of Figure 1.
DETAILED DESCRIPTION
A hybrid power train for vehicles 100 comprises an internal combustion engine (hereinafter referred to as the engine 10), a unidirectional torque transfer coupling 20, an integrated starter/ booster / generator machine 30 (also referred to as integrated generator 30), a unidirectional torque transfer device 40, and a hybrid mechanical torque multiplication assembly 50. The unidirectional torque transfer coupling 20 is operatively coupled with the engine 10 and is configured to receive torque generated by the engine 10 and transfer torque to an integrated generator 30. More specifically, the integrated generator 30 is operatively coupled with the unidirectional torque transfer coupling 20 and is configured to selectively receive torque from the unidirectional torque transfer coupling 20. A hybrid torque multiplication assembly 50 is operatively coupled with the integrated generator 30 and the engine 10 and is further configured to be selectively actuated by the integrated generator 30 and/or by the engine 10.
The unidirectional torque transfer coupling 20 is connected to the engine 10 by a first connecting element 12. The unidirectional torque transfer coupling 20 includes an input element (flywheel) 14, a damper 16, a first output element 18 and a second output element 19. The input element (flywheel) 14 is connected to the engine by the first connecting element 12. The damper 16 is disposed operatively between the input element (flywheel) 14 and the first output element 18. The first output element 18 is connected to the damper 16 and in an operative configuration the first output element 18 rotates. The second output element 19 is selectively connected to the first output element 18, thereby causing the rotation of the second output element 19 on said selective coupling. The damper 16 isolates torsional vibrations of the engine 10 and, hence, prevents the torsional vibrations from being transferred further in the hybrid power train 100 of the vehicle. Typically, the damper 16 is a torsional spring or an air damper or a fluid damper.
In an embodiment, the hybrid powertrain 100 includes a starting assembly 60 configured to selectively actuate the engine 10 during start up condition. The starting assembly 60 includes a low voltage energy storage device 66 and a first starter 60A in electrical communication with the low voltage energy storage device 66 via a second connecting element 68. The first starter 60A includes a first rotor 62 and a first stator 64. The input element (flywheel) 14 is selectively actuated by the engine 10 and the first starter 60. The first rotor 62 is configured to rotate within the first stator 64, wherein the first rotor 62 is operatively coupled with the input element 14 (flywheel) of the unidirectional torque transfer coupling 20 to provide an initial torque to the engine 10 during start up condition. Typically, a gear arrangement or an upgrade of an alternator supplies the power to the low voltage auxiliaries is disposed in between the first starter 60 and the input element (flywheel) 14.
The second output element 19 is further connected to a third connecting element 22 which is typically a shaft. Typically, the unidirectional torque transfer coupling 20 is a centrifugal clutch having a ball and socket arrangement as shown in Figure 2. The ball and socket arrangement includes a plurality of balls 20a, a plurality of springs 20b and a socket 20c.
In a first mode of operation, when the value of torque generated by the engine 10 exceeds the value of torque generated by the integrated generator 30 and when the rotational speed of the integrated generator 30 equals the rotational speed of the engine 10, the engine 10 is coupled with the integrated generator 30, thereby resulting in the addition of torque to obtain a first driving torque which drives the hybrid torque multiplication assembly. More specifically, when the rotational speed of the first output element 18 is equal to the rotational speed of the third connecting element 22, then the unidirectional torque transfer coupling 20 is configured to engage with the third connecting element 22, thereby permitting transfer of torque from the engine 10 to the third connecting element 22. The unidirectional torque transfer coupling 20 is configured to engage with the third connecting element 22 because of the engagement between the first output element 18 and the second output element 19.
In a second mode of operation, when the rotational speed of the integrated generator 30 exceeds the rotational speed of the engine 10, the engine 10 is decoupled from the integrated generator 30, and the integrated generator 30 drives the hybrid torque multiplication assembly. More specifically, when the rotational speed of the first output element 18 is less than the third connecting element 22, then the unidirectional torque transfer coupling 20 is configured to overrun by disengagement between the first output element 18 and the second output element 19. Moreover, the engine 10 is freewheeled from the third connecting element 22 for preventing the transfer of torque from the engine 10 to the third connecting element 22.
In another embodiment, the integrated generator 30 includes a second rotor 34 and the third connecting element 22 disposed operatively between the second rotor 34 and the second output element 19 to facilitate a coupling of the second rotor 34 with the second output element 19. A second stator 32 is disposed around the second rotor 34 and is configured to receive, via a fourth connecting element 39, an alternating current from a power inverter 38 which is in electrical communication with an energy storage device 36. The integrated starter/ booster / generator machine 30 is connected to the second output element 19 of the unidirectional torque transfer coupling 20 through the third connecting element 22. The integrated starter/booster/generator machine 30 is an electrical actuation system for electrically actuating the hybrid mechanical torque multiplication assembly 50. The integrated starter/ booster / generator machine 30 includes a second stator 32 and the second rotor 34. The second stator 32 is configured to receive electrical power from or provide electrical power to the energy storage device 36 via a direct current high voltage network 37. The power inverter 38 is disposed between the second stator 32 and the energy storage device 36 for converting direct current of the energy storage device 36 to the alternating current required by the second stator 32. The fourth connecting element 39 is used to connect the power inverter 38 and the second stator 32.
In an embodiment, the hybrid powertrain includes a unidirectional torque transfer device 40 for facilitating selective engagement of a fifth connecting element 42 which is operatively coupled with the second rotor 34 with a sixth connecting element 52 which is disposed operatively between the unidirectional torque transfer device 40 and the hybrid torque multiplication assembly 50 and which drives the hybrid torque multiplication assembly. The unidirectional torque transfer device 40 is a clutch that enables engagement and dis-engagement of the fifth connecting element 42 with the hybrid mechanical torque multiplication assembly 50. More specifically, in an engaged configuration, the hybrid mechanical torque multiplication assembly 50 is connected and actuated either by the engine 10 or the integrated starter/ booster / generator machine 30. Typically, the clutch may be a wet clutch or a manual clutch or automated dry clutch. The wet clutch is engageable at a controlled slip to enable smooth transitions in power flow. Alternatively, the automated dry clutch is similar to conventional manual mechanical torque multiplication assembly shifting clutch.
The hybrid mechanical torque multiplication assembly 50 is connected to the unidirectional torque transfer device 40 through the sixth connecting element 52 (also known as an engine connection element). The hybrid mechanical torque multiplication assembly 50 has a gear arrangement (not illustrated in Figures) and clutches (not illustrated in Figures). The gear arrangement includes shafts with intermeshing gears. The clutches are selectively engaged with the gear arrangement and typically are manually operated by a driver (not shown in Figures) or is automatically operated by an automated mechanism (not shown in Figures).
A hybrid vehicle (not illustrated in Figures) equipped with the system 100 is actuated and the hybrid vehicle and runs under normal driving conditions. During the normal driving conditions (i.e. the assist mode), the engine 10 is coupled with the integrated starter/ booster / generator machine 30 and the hybrid mechanical torque multiplication assembly 50 through the first connecting element 12, the input element (flywheel) 14, the damper 16, the first output element 18, the second output element 19 and the third connecting element 22.
When the vehicle is under a restart / start condition, the engine 10 is actuated by the first starter 60 which gets power from the low voltage energy storage device 66. The first starter 60 actuates the rotational movement of the input element (flywheel). The vehicle can be restarted under either normal restart standstill condition or restart under emergency or driving condition (not standstill condition).
Under normal restart standstill conditions, the first starter 60 gets actuated and provides the starting torque required to start the engine 10. Under this condition the first starter 60 initially provides torque to restart the engine 10 and also simultaneously provide nominal boost through the integrated starter/ booster / generator machine 30. Once the engine gets stabilized, the first starter 60 is de-actuated.
Under restart under emergency or driving condition when the vehicle is not in a standstill position (electrical creep condition), the first starter 60 provides the starting torque required to start the engine 10, wherein initially the starting torque and speed of the engine 10 is less than torque and speed of the integrated starter/ booster/generator machine 30. Once the engine 10 generates torque which exceeds torque generated by the first starter 60, the first output element engages with the second output element of the unidirectional torque transfer coupling 20 and a combined torque of the engine 10 and the integrated starter/ booster / generator machine 30 is provided to the hybrid mechanical torque multiplication assembly 50. After torque is provided to the hybrid mechanical torque multiplication assembly 50, the first starter 60 is shut-off and torque generated by the first starter 60 is gradually reduced, and simultaneously torque generated by the engine 10 is increased without any loss of traction torque at the wheels of the vehicle.
The hybrid power train of the vehicle 100 of the present disclosure has only one coupling that is unidirectional torque transfer coupling 20 as compared to conventional hybrid power train vehicles (not illustrated in Figures) which has at least two couplings. Also, the hybrid power train of the vehicle 100 has only one clutch i.e. the unidirectional torque transfer device 40 as compared to conventional hybrid power train vehicles. Hence, the hybrid power train of the vehicle 100 has comparatively less elements. Also, the elements of the hybrid power train of the vehicle 100 is comparatively small in size and hence reduces overall mass and comparatively small space for installation on the vehicle and provides ease for assembling. Further, the unidirectional torque transfer device 40 provides the engine 10 to start and stop without stopping the power train. The hybrid power train of the vehicle 100 has comparatively long travel damper because the damper 16 is not integrated with the clutch which provides comparatively smooth ride of vehicles.
TECHNICAL ADVANCES
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a connecting structure that:
• which has a reduced number of elements as compared to the conventional hybrid powertrains; and
• which has a compact configuration and a reduced mass.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:1. A hybrid powertrain comprising:
o an engine;
o a unidirectional torque transfer coupling operatively coupled with said engine and configured to receive torque generated by said engine and transfer torque;
o an integrated generator operatively coupled with said unidirectional torque transfer coupling and configured to selectively receive torque from said unidirectional torque transfer coupling; and
o a hybrid torque multiplication assembly operatively coupled with said integrated generator and said engine and configured to be selectively actuated by said integrated generator and/or said engine, wherein:
- in a first mode of operation, when the value of torque generated by said engine exceeds the value of torque generated by said integrated generator and when the rotational speed of said integrated generator equals the rotational speed of said engine, said engine is coupled with said integrated generator, thereby resulting in torque addition thereof to obtain a first driving torque which drives said hybrid torque multiplication assembly; and
- in a second mode of operation, when the rotational speed of said integrated generator exceeds the rotational speed of said engine, said engine is decoupled from said integrated generator, and said integrated generator drives said hybrid torque multiplication assembly.

2. The hybrid powertrain as claimed in claim 1, wherein said unidirectional torque transfer coupling includes:
o an input element;
o a first connecting element disposed operatively between said engine and said input element for coupling said engine to said unidirectional torque transfer coupling;
o a first output element being resiliently coupled with said input element via a damper disposed operatively therebetween; and
o second output element selectively connectable to said first output element.

3. The hybrid powertrain as claimed in claim 1 or claim 2, which includes starting assembly configured to selectively actuate said engine during start up condition, said starting assembly comprises:
o a low voltage energy storage device;
o a first stator in electrical communication with said low voltage energy storage device via a second connecting element; and
o a first rotor configured to rotate within said first stator, wherein said first rotor is operatively coupled with said input element to provide an initial torque to said engine during start up condition thereof.

4. The hybrid powertrain as claimed in claim 2, wherein said integrated generator includes:
o a second rotor;
o a third connecting element disposed operatively between said second rotor and said second output element to facilitate a coupling of said second rotor with said second output element; and
o a second stator disposed around said second rotor and configured to receive, via a fourth connecting element, an alternating current from a power inverter which is in electrical communication with an energy storage device;

5. The hybrid powertrain as claimed in claim 4, which includes a unidirectional torque transfer device for facilitating selective engagement of a fifth connecting element which is operatively coupled with said second rotor with a sixth connecting element which is disposed operatively between said unidirectional torque transfer device and said hybrid torque multiplication assembly and which drives said hybrid torque multiplication assembly.

6. The hybrid powertrain as claimed in claim 2, wherein said damper is a torsion spring.