Claims:1. A system (100) for engaging or disengaging at least one drivetrain (300B) to a power source (200B) of an all-wheel drive vehicle (500), said system (100) comprising:
a first rotatable unit (102) adapted to be rotatably connected to an output shaft (202S) of the power source (200B);
a second rotatable unit (104) adapted to be rotatably connected to an input shaft (302S) of a power transmission unit (302G) of the drivetrain (300B);
a shifting member (106) adapted to be rotatably connected to said second rotatable unit (104);
a shift fork (108) adapted to be movably engaged with said shifting member (106);
a plurality of linear actuators (110A, 110B), where each of said linear actuator (110A, 110B) includes a movable member (110AM, 110BM) adapted to be movably connected to said shift fork (108); and
a controller unit (112) adapted to be provided in communication with said linear actuators (110A, 110B),
wherein
said controller unit (112) is adapted to at least one of actuate and de-actuate said linear actuators (110A, 110B); and
said movable member (110AM, 112BM) of said linear actuators (110A, 110B) are adapted to move said shifting member (106) through said shift fork (108) between one of an engaged position and a disengaged position, wherein in the engaged position said shifting member (106) is adapted to engage said second rotatable unit (104) with said first rotatable unit (102) thereby engaging the drivetrain (300B) with the power source (200B), wherein in the disengaged position said shifting member (106) is adapted to dis-engage said second rotatable unit (104) from said first rotatable unit (102) thereby dis-engaging the drivetrain (300B) from the power source (200B).

2. The system (100) as claimed in claim 1, wherein said system (100) includes,
a vehicle control unit (120) in communication with the controller unit (112);
an user interface unit (114) adapted to communicate user input(s) about operating the vehicle in one of a two wheel drive mode or a all-wheel drive mode to said vehicle control unit (120); and
a power source control unit (122) in communication with said vehicle control unit (120), wherein said power source control unit (122) is adapted to actuate or de-actuate the power source (200B) in the all-wheel drive mode or the two wheel drive mode respectively based on the instructions sent by said vehicle control unit (120) to said power source control unit (122),
wherein
said vehicle control unit (120) is adapted to instruct said controller unit (112) to operate the vehicle in one of the two wheel drive mode and the all-wheel drive mode based on at least one of,
input(s) from said user interface unit (114); and
input(s) about at least one of operating parameters of the vehicle, operating terrain and weather conditions received through at least one of an electronic module and sensors provided to the vehicle.

3. The system as claimed in claim 2, wherein said system (100) includes,
a vehicle speed sensor (118) adapted to sense the vehicle speed and communicate the measured vehicle speed to said vehicle control unit (120); and
a power source speed sensor (124) adapted to sense operating speed of the output shaft (202S) of the power source (200B) and communicates the measured speed of the output shaft (202S) of the power source (200B) to said vehicle control unit (120),
wherein
said controller unit (112) is adapted to actuate or de-actuate said linear actuators (110A, 110B) based on instructions from said vehicle control unit (120);
said user interface unit (114) is at least one of a switch, a button, a lever, a knob, a touchscreen, a user interface on vehicle infotainment system and an application present on a user device;
said shifting member (106) disengages said second rotatable unit (104) from said first rotatable unit (102) thereby disengaging the drivetrain (300B) from the power source (200B) when the vehicle is operated in the two wheel drive mode; and
said shifting member (106) engages second rotatable unit (104) with said first rotatable unit (102) thereby engaging the drivetrain (300B) with the power source (200B) when the vehicle is operated in the all-wheel drive mode.

4. The system (100) as claimed in claim 1, wherein said system (100) includes,
a plurality of fork support rails (107) adapted to support said shift fork (108), wherein said shift fork (108) is slidably mounted on said fork support rails (107); and
a housing (101) adapted to accommodate said first rotatable unit (102), said second rotatable unit (104), said shifting member (106), said shift fork (108), said fork support rails (107), said plurality of linear actuators (110A, 110B) and said controller unit (112), where said controller unit (112) is integrated within said housing (101).

5. The system (100) as claimed in claim 1, wherein said controller (112) is adapted to operate an electro pump (116) which is adapted to circulate (pump) a lubricant from a lubricant reservoir (117) to at least one nozzle,
wherein
said nozzle is adapted to direct the lubricant on said first rotatable unit (102), said second rotatable unit (104) and said shifting member (106) when the vehicle is operated in the four wheel drive mode.

6. The system (100) as claimed in claim 1, wherein said first rotatable unit (102) includes,
a synchronizer cone (102A) adapted to be mounted on the output shaft (202S) of the power source (200B); and
a synchronizer ring (102B) adapted to be engaged with said synchronizer cone (102A),
wherein
said shifting member (106) is engaged with said synchronizer ring (102B) in the engaged position in which the vehicle is operated in the four wheel drive mode; and
said shifting member (106) is disengaged from the synchronizer ring (102B) in the disengaged position in which the vehicle is operated in the two wheel drive mode.

7. The system (100) as claimed in claim 4, wherein said plurality of linear actuators (110A, 110B) includes,
a plurality of first linear actuators (110A), each of said first linear actuator (110A) is mounted to an inner portion of said housing (101); and
a plurality of second linear actuators (110B), each of said second linear actuator (110B) is mounted to another inner portion of said housing (101) opposite to said first linear actuators (110A),
wherein
said shift fork (108) is disposed between said first and second linear actuators (110A, 110B);
each of said first and second linear actuators (110A, 110B) includes a solenoid unit (110AS, 110BS) in communication with said controller unit (112), where a portion of said movable member (110AM, 110BM) of each of said first and second linear actuator (110A, 110B) is movably received inside corresponding said solenoid unit (110AS, 110BS);
said movable member (110AM) of each of said first linear actuator (110A) is adapted to move said shifting member (106) through said shift fork (108) to the engaged position on at least one of de-energization of said solenoid unit (110AS) of each of said first linear actuator (110A) and energization of said solenoid unit (110BS) of each of said second linear actuator (110B) by said controller unit (112);
said movable member (110BM) of each of said second linear actuator (110A) is adapted to move said shifting member (106) through said shift fork (108) to the dis-engaged position on at least one of de-energization of said solenoid unit (110BS) of each of said second linear actuator (110B) and energization of said solenoid unit (110BS) of each of said first linear actuator (110A) by said controller unit (112); and
said movable member (110AM, 110BM) of each of said linear actuator (110A, 110B) is at least a plunger.

8. The system (100) as claimed in claim 1, wherein each of said linear actuator (110A, 110B) is at least one of a hydraulic linear actuator, a pneumatic linear actuator and an electric linear actuator.

9. A method (600) for engaging or dis-engaging drivetrain(s) (300B) to power source(s) (200B) of an all-wheel drive vehicle (500), said method (600) comprising:
at least one of de-actuating and actuating, by a controller unit (112), each linear actuator (110A, 110B) based on instructions sent by a vehicle control unit (120) to the controller unit (112);
moving, by a movable member (110AM, 110BM) of each linear actuator (110A, 110B), a shifting member (106) through a shift fork (108) in a first direction in response to operating the linear actuators (110A, 110B) by the controller unit (112); and
engaging, by the shifting member (106), a first rotatable unit (102) with a second rotatable unit (104) thereby engaging the power source (200B) with the drivetrain (300B) in response to moving, by the linear actuators (110A, 110B), the shifting member (106) in the first direction.

10. The method (600) as claimed in claim 9, wherein said method (600) comprises,
communicating, by at least one of an user interface unit (114), an electronic module and sensors provided to the vehicle, an input about operating the vehicle in an all-wheel drive mode and input(s) about at least one of operating parameters of the vehicle, operating terrain and weather conditions to the vehicle control unit (120) respectively prior to said de-actuating and actuating each linear actuator (110A, 110B) by the controller unit (112);
actuating the power source (200B) by a power source control unit (122) based on signal sent by the vehicle control unit (120) to the power source control unit (122) when the vehicle control unit (120) receives at least one of input about operating the vehicle in the all-wheel drive mode from the user interface unit (114) and inputs from the electronic module and sensors provided to the vehicle;
monitoring and communicating, by a vehicle speed sensor (118), speed of vehicle to the vehicle control unit (120);
monitoring and communicating, by a power source speed sensor (124), speed of an output shaft (202S) of the second power source (200B) to the vehicle control unit (120);
comparing, by the vehicle control unit (120), the operating speed of the output shaft (202S) of the power source (200B) with an operating speed of the vehicle; and
instructing by, a vehicle control unit 120), the controller unit (112) to operate the vehicle in the all-wheel drive mode when the operating speed of the output shaft (202S) of the power source (200B) matches with the operating speed of the vehicle (500).

11. The method (600) as claimed in claim 9, wherein said method (600) comprises,
communicating by, at least one of the user interface unit (114), the electronic module and sensors provided to the vehicle, an input about operating the vehicle in a two wheel drive mode and input(s) about at least one of operating parameters of the vehicle, operating terrain and weather conditions to the vehicle control unit (120) respectively; and
instructing the controller unit (112) by the vehicle control unit 120) to operate the vehicle in the two wheel drive mode based on at least one of inputs from the user interface unit (114), the electronic module and sensors provided to the vehicle.

12. The method (600) as claimed in claim 11, wherein said method (600) comprises,
at least one of de-actuating and actuating, by the control unit (112), each linear actuator (110B, 110A) based on instructions sent by the vehicle control unit (120) to the controller unit (112);
moving, by the movable member (110BM, 110AM) of each linear actuator (110B, 110A), the shifting member (106) through the shift fork (108) in a second direction in response to operating the linear actuators (110B, 110A) by the controller unit (112); and
disengaging, by the shifting member (106), the second movable member (104) from the first rotatable unit (102) thereby disengaging the power source (200B) from the drivetrain (300B) in response to moving, by the linear actuators (110B, 110A), the shifting member (106) in the second direction.
, Description:TECHNICAL FIELD

[001] The embodiments herein generally relate to all-wheel drive vehicles and more particularly, to a system and method for engaging or disengaging drivetrain(s) with respect to power source(s) of an all-wheel drive vehicle.

BACKGROUND
[002] Improved vehicle stability while traversing rain soaked or ice or snow-covered highways, handling and control on gravel or uneven pavement and simply maintaining traction in off road situations are benefits of a four-wheel drive vehicle or all-wheel drive vehicle. Such vehicles have complex drivetrains in which an additional driveline (secondary driveline) is provided along with a primary driveline, where the secondary driveline includes an axle, transmission and a prop shaft, and other driveline units. The all-wheel-drive (AWD) systems tend to degrade vehicle fuel economy due to increased driveline parasitic losses even when AWD is not activated. These parasitic losses occur because some parts of the driveline continue to be driven by the engine or electric motor, or the secondary drive wheels and their rotation cause a drag torque to be exerted on the driving element.
[003] In an effort to minimize driveline losses (i.e., viscous drag, friction, inertia and oil churning) associated with secondary driveline being back-driven when no drive torque is transmitted thereto, it is known to incorporate a disconnect system that is configured to uncouple components of the secondary driveline such as, for example, the rear wheels or the rear differential from the remainder of the secondary driveline.
[004] These disconnect systems provide a significant fuel economy benefit, but they pose challenges including getting the driveline reconnected quickly when the AWD system must be activated, and maintaining system durability through many driveline disconnect/reconnect cycles. Meeting these challenges is complicated when some or all of the disconnect clutch designs are constrained by size and packaging limitations, or a desire to minimize drag.
[005] Further, in electric vehicles, the driveline includes a permanent magnet (PM) electric motor which rotates at high speeds and is capable of generating very high voltages. In case of vehicle breakdown or when the vehicle is towed due to internal failure, the PM motor continues to be connected to the vehicle driveline, and generate voltage in the motor windings and at the motor terminals. The resultant voltage developed at the motor terminals in this condition increases the possibility of fires or permanent damage within the electric motor which may result in damage to its electronic circuit boards, capacitors, diodes, motor windings, etc.
[006] Therefore, there exists a need for a system and method for engaging or disengaging drivetrain(s) with respect to power source(s) of an all-wheel drive vehicle, which eliminates the aforementioned drawbacks.

OBJECTS

[007] The principal object of an embodiment herein is to provide a system for engaging or disengaging drivetrain(s) with respect to power source(s) of an all-wheel drive vehicle.
[008] Another object of an embodiment herein is to provide a system for operating a vehicle in one of an all-wheel drive mode and a two-wheel drive mode.
[009] Yet another object of an embodiment herein is to provide a system for engaging or disengaging at least one drivetrain with respect to power source of an all-wheel drive vehicle which has an electric motor installed in the vehicle such as but not limited to an electric vehicle (EV), fuel cell electric vehicle (FCEV) and hybrid electric vehicle (HEV).
[0010] Yet another object of an embodiment herein is to provide a system for disengaging a secondary drivetrain from a secondary power source when the all-wheel drive vehicle is driven by a primary power source through a primary driveline in a two wheel drive mode.
[0011] Still another object of an embodiment herein is to provide a system for engaging or disengaging at least one drivetrain with respect to power source of the all-wheel drive vehicle having two drivetrains in which each drivetrain is independently powered by a separate power source.
[0012] Still another object of an embodiment herein is to provide a method for disengaging at least one drivetrain from a power source of an all-wheel drive vehicle.
[0013] Yet another object of an embodiment herein is to provide a synchronizer based disengaging system (synchronizer based clutch system) for smoothly engaging or disengaging at least one drivetrain with respect to power source of the all-wheel drive vehicle.
[0014] Another object of an embodiment herein is to provide a system which includes linear actuators and a controller to selectively engage or disengage the power source (electric motor) with respect to at least one drivetrain of the vehicle.
[0015] Also, another object of an embodiment herein is to provide electrically actuated linear actuators to selectively engage or disengage the power source (electric motor) with respect to the drivetrain of an all-wheel drive vehicle.
[0016] Another object of an embodiment herein is to provide hydraulically or pneumatically actuated linear actuators to selectively engage or disengage power source(s) (electric motor(s)) with respect to the drivetrain(s) of an all-wheel drive vehicle.
[0017] Another object of an embodiment herein is to provide solenoid actuated linear actuators to selectively engage or disengage the power source(s) electric motor(s)) with respect to the drivetrain(s) of an all-wheel vehicle.
[0018] Another object of an embodiment herein is to provide a drivetrain disengaging system (drivetrain clutch system) having the controller provided in communication with an electro-pump which is adapted to supply a lubricant from a reservoir to all dynamic running components of the drivetrain disengaging system.
[0019] Yet another object of an embodiment herein is to provide a method for engaging or disengaging at least one drivetrain with respect to a power source of an all-wheel drive vehicle.
[0020] Another object of an embodiment herein is to provide a system for engaging or disengaging at least one drivetrain with respect to the power source of the vehicle, which is simple in construction, easy to assemble and inexpensive.
[0021] Another object of an embodiment herein is to provide a system for engaging or disengaging at least one drivetrain with respect to a power source of an all-wheel drive vehicle, which is reliable and responsive.
[0022] Another object of an embodiment herein is to provide a system for at least one of engaging and disengaging first and second drivetrain(s) with respect to first and second power source(s) of an all-wheel drive vehicle.
[0023] Another object of an embodiment herein is to provide a system for at least one of engaging and disengaging each power source with respect to corresponding wheel of an all-wheel drive vehicle, where the vehicle has separate power source (electric motor) coupled to each wheel.
[0024] Another object of an embodiment herein is to provide a system for at least one of engaging and disengaging drivetrain(s) with respect to power source(s) of an all-wheel drive vehicle, which reduces drag torque of the drivetrain thereby increasing the driving range of the vehicle.
[0025] Another object of an embodiment herein is to provide a system for smooth shifting between one of a two wheel drive mode and an all-wheel drive mode in an all-wheel drive vehicle.
[0026] Another object of an embodiment herein is to provide the drivetrain disengaging system in the all-wheel drive vehicle, which reduces drag torque of secondary drivetrain, and prevents the permanent magnet motors from generating unwanted current and reduction of higher thermal heat produced during towing of the vehicle or when the vehicle is operated in two wheel drive mode.
[0027] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

 
BRIEF DESCRIPTION OF DRAWINGS

[0028] The embodiments of the invention are illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0029] FIG. 1 depicts a schematic view of power source(s) and drivetrain(s) of an all-wheel drive vehicle, according to an embodiment of the invention as disclosed herein;
[0030] FIG. 2 depicts a schematic view of a system for engaging or dis-engaging the drivetrain with respect to the power source in the all-wheel drive vehicle, according to an embodiment of the invention as disclosed herein;
[0031] FIG. 3 depicts a block diagram of the system for engaging or disengaging the drivetrain with respect to the power source in the all-wheel drive vehicle, according to an embodiment of the invention as disclosed herein;
[0032] FIG. 4 depicts a cross-sectional view showing power flow from the power source to the drivetrain through rotatable units of the driveline disengaging system (driveline clutch system), according to an embodiment of the invention as disclosed herein;
[0033] FIGS. 5a and 5b depict views of the driveline disengaging system in a disengaged position in which the vehicle is operated in a two-wheel drive (2wd) mode, and an engaged position in which the vehicle is operated in a four-wheel drive (4wd) mode, respectively, according to an embodiment of the invention as disclosed herein;
[0034] FIGS. 6a and 6b depict a side view of the driveline disengaging system in the disengaged position and the engaged position, according to an embodiment of the invention as disclosed herein; and
[0035] FIG. 7 depicts a flow chart of a method for engaging or disengaging at least one drivetrain with respect to a power source of an all-wheel drive vehicle.

DETAILED DESCRIPTION
[0036] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed 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.
[0037] The embodiments herein achieve a system for at least one of engaging and disengaging drivetrain(s) with respect to power source(s) of an all-wheel drive vehicle. Further, embodiments herein achieve synchronizer based disengaging system (synchronizer based clutch system) for smoothly engaging or disengaging at least one drivetrain with respect to power source of the all-wheel drive vehicle. Further, embodiments herein achieve a system for operating a vehicle in one of an all-wheel drive mode and a two-wheel drive mode. Further, the embodiments herein achieve a method for engaging or dis-engaging at least one drivetrain with respect to a power source of the all-wheel drive vehicle. Furthermore, the embodiments herein achieve system for disengaging a secondary drivetrain from a secondary power source when the all-wheel drive vehicle is driven by a primary power source through a primary driveline in the two wheel drive mode. Additionally, the embodiments herein achieve system for engaging or disengaging at least one drivetrain with respect to power source of the all-wheel drive vehicle having two drivetrains in which each drivetrain is independently powered by a separate power source. Referring now to the drawings, and more particularly to FIGS. 1 through 7, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0038] The embodiments herein relate to electric powered vehicles including for example, electric powered vehicles (EVs), hybrid electric vehicles (HEVs), and fuel cell electric vehicles (FCEVs). The vehicle herein relate to an all-wheel drive vehicle (500) which includes two drivetrains (300A, 300B) in which each drivetrain (300A, 300B) is independently powered by a separate power source (200A, 200B). FIG. 1 depicts a schematic view of power source(s) (200A, 200B) and drivetrain(s) (300A, 300B) of an all-wheel drive vehicle (500), according to an embodiment of the invention as disclosed herein. In an embodiment, the all-wheel drive vehicle (500) includes a drivetrain disengaging system (100), a first power source (200A), a second power source (200B), a first drivetrain (300A) and a second drivetrain (300B). In an embodiment, drivetrain disengaging system (100) is adapted for engaging or disengaging the second power source (200B) with respect to the second drivetrain (300B). The first power source (200A) is considered to be a primary power source. In one example, the first power source (200A) is considered to be an engine. In another example, the first power source (200A) is considered to be an electric motor. The first power source (200A) is adapted to drive the first drivetrain (300A). The second power source (200B) is a secondary power source. For example, the second power source (200B) is considered to be an electric motor. It is also within the scope of the invention to replace the engine or electric motor with any other power sources. The second power source (200B) is adapted to drive the second drivetrain (300B). The first drivetrain (300A) is considered to be a primary drivetrain. The first drivetrain (300) is adapted to be drive front wheels (FW) of the vehicle. The second drivetrain (300B) is considered to be a secondary power train. The second drivetrain (300B) is adapted to drive rear wheels (RW) of the vehicle. FIG. 2 depicts a schematic view of the drivetrain disengaging system (100) for engaging or dis-engaging the drivetrain (300B) with respect to the power source (200B) in the all-wheel drive vehicle (500), according to an embodiment of the invention as disclosed herein. FIG. 3 depicts a block diagram of the drivetrain disengaging system (100) for engaging or disengaging the drivetrain (300B) with respect to the power source (200B) in the all-wheel drive vehicle (500), according to an embodiment of the invention as disclosed herein. In an embodiment, the drivetrain disengaging system (100) includes a housing (101), a first rotatable unit (102), (as shown in fig. 4 to fig. 5b), a second rotatable unit (104), (as shown in fig. 4 to fig. 5b), a shifting member (106), (as shown in fig. 4 to fig. 5b), a plurality of fork support rails (107) (as shown in fig. 6a and fig. 6b), a shift fork (108) (as shown in fig. 4 to fig. 6b), a plurality of linear actuators (110A, 110B), (as shown in fig. 6a and fig. 6b), a controller unit (112), an user interface unit (114), a vehicle speed sensor (118), a vehicle control unit (120), a power source control unit (122) and a power source speed sensor (124). For the purpose of this description and ease of understanding, the drivetrain disengaging system (100) is explained herein below with reference to dis-engaging the second drivetrain (300B) from the second power source (200B) when the all-wheel drive vehicle (500) is driven by the first power source (200A) through the first driveline (200A) in a two wheel drive mode. It is understood that the embodiments described herein could be used in any vehicle having dual drivetrains powered by a single power source or any other vehicles having independently powered wheels.
[0039] The housing (101) is adapted to accommodate the first rotatable unit (102), the second rotatable unit (104), the shifting member (106), the shift fork (108), the fork support rails (107), the plurality of linear actuators (110A, 110B) and the controller unit (112), where the controller unit (112) is integrated within the housing (101).
[0040] The first rotatable unit (102) is adapted to be rotatably connected to an output shaft (202S) of the second power source (200B). The first rotatable unit (102) includes a synchronizer cone (102A) and a synchronizer ring (102B), (as shown in fig. 5a and fig. 5b). The synchronizer cone (102A) is adapted to be mounted on an output shaft ((202S), (as shown in fig. 4) of the second power source (200B). Further, the first rotatable unit (102) may include friction rings and any other components as present in a synchronizer unit. The synchronizer ring (102B) is adapted to be engaged with the synchronizer cone (102A). The second rotatable unit (104) is adapted to be rotatably connected to an input shaft ((302S), (as shown in fig. 4) of a power transmission unit ((302G), (as shown in fig. 2) of the second drivetrain (300B).
[0041] The shifting member (106) is adapted to be rotatably connected to the second rotatable unit (104). The shifting member (106) is adapted to be moved by the linear actuators (110A, 110B) between one of an engaged position and a disengaged position. In the disengaged position, thee shifting member (106) is adapted to disengage the second rotatable unit (104) from the first rotatable unit (102) thereby disengaging the second drivetrain (300B) from the second power source (200B) when the vehicle is operated in the two wheel drive mode. In the engaged position, the shifting member (106) is adapted to engage the second rotatable unit (104) with the first rotatable unit (102) thereby engaging the second drivetrain (300B) with the second power source (200B) when the vehicle is operated in the four wheel drive mode. The shifting member (106) is engaged with the synchronizer ring (102B) of the first rotatable unit (102) in the engaged position in which the vehicle is operated in the four wheel drive mode. The shifting member (106) is disengaged from the synchronizer ring (102B) of the first rotatable unit (102) in the disengaged position in which the vehicle is operated in the two wheel drive mode.
[0042] The plurality of fork support rails (107) are adapted to support the shift fork (108), where the shift fork (108) is slidably mounted on the fork support rails (107). The shift fork (108) is adapted to be movably engaged with the shifting member (106). The shift fork (108) is disposed between the first and second linear actuators (110A, 110B).The shift fork (108) is adapted to move the shifting member (106) between one of the engaged position and the disengaged position when the shift fork (108) is moved by the linear actuators (110A, 110B).
[0043] The plurality of linear actuators (110A, 110B includes a plurality of first linear actuator (110A) and a plurality of second linear actuators (110B). Each first linear actuator (110A) is mounted to an inner portion of the housing (101). Each second linear actuator (110B) is mounted to another inner portion of the housing (101) opposite to the first linear actuators (110A). Each linear actuator (110A, 110B) comprises a movable member ((110AM, 110BM), (as shown in fig. 6a and fig. 6b)) adapted to be movably connected to the shift fork (108). The movable member (110AM, 110BM) of the linear actuators (110A, 110B) are adapted to move the shifting member (106) through the shift fork (108) between one of the engaged position in which the shifting member (106) engages the second rotatable unit (104) with the first rotatable unit (102), and the disengaged position in which the shifting member (106) dis-engages the second rotatable unit (104) from the first rotatable unit (102) based on instructions sent by the controller unit (112) to the linear actuators (110A, 110B). The movable member (110AM) of each first linear actuator (110A) is adapted to push the shifting member (106) through the shift fork (108) and correspondingly, the movable member (110BM) of each second linear actuator (110B) is adapted to pull the shifting member (106) through the shift fork (108) thereby moving the shifting member (106) to the engaged position. The movable member (110BM) of each second linear actuator (110B) is adapted to push the shifting member (106) through the shift fork (108) and correspondingly, the movable member (110AM) of each first linear actuator (110A) is adapted to pull the shifting member (106) through the shift fork (108) thereby moving the shifting member (106) to the dis-engaged position. In an embodiment, each first and second linear actuators (110A, 110B) includes a solenoid unit ((110AS, 110BS), (as shown in fig. 6a and fig. 6b)) in communication with the controller unit (112), where a portion of the movable member (110AM, 110BM) of each first and second linear actuator (110A, 110B) is movably received inside corresponding solenoid unit (110AS, 110BS). The solenoid unit ((110AS, 110BS of each first and second linear actuator (110A, 110B) includes a solenoid body (not shown), a coil of wires (not shown) and a spring (not shown), where the spring (not shown) is adapted to be located in the solenoid body immediately below the movable member (110AM, 110BM) of corresponding first and second linear actuator (110A, 110B). The movable member (110AM) of each first linear actuator (110A) is adapted to move the shifting member (106) through the shift fork (108) to the engaged position on at least one of de-energization of the solenoid unit (110AS) of each first linear actuator (110A) and energization of the solenoid unit (110BS) of each second linear actuator (110B) by the controller unit (112). The movable member (110BM) of each second linear actuator (110A) is adapted to move the shifting member (106) through the shift fork (108) to the dis-engaged position on at least one of de-energization of the solenoid unit (110BS) of each second linear actuator (110B) and energization of the solenoid unit (110BS) of each first linear actuator (110A) by the controller unit (112). The movable member (110AM, 110BM) of each linear actuator (110A, 110B) is at least a plunger. In another embodiment, each linear actuator (110A, 110B) is one of a hydraulic linear actuator (hydraulic cylinder assembly), a pneumatic linear actuator (pneumatic cylinder assembly) and an electric linear actuator (electric linear motor). It is also within the scope of the invention to replace either one of each first linear actuator (110A) and second linear actuator (110B) with springs for achieving engaging or disengaging of the second drivetrain (300B) with respect the second power source (200B). Further, it is also within the scope of the invention to consider the first second actuators (110A, 110B) as a combination of the electric linear actuator, the hydraulic linear actuator and pneumatic linear actuator.
[0044] The controller unit (112) is adapted to be provided in communication with the first and second linear actuators (110A, 110B). In one embodiment, the controller unit (112) is integrated (located) within the housing (101). The controller unit (112) is an electronic controller unit (ECU) which in communication with the vehicle control unit (120). The controller (112) is adapted to actuate or de-actuate the linear actuators (110A, 110B) based on instructions from the vehicle control unit (120). The controller (112) is adapted to operate an electro pump ((116), (as shown in fig. 2)) which is adapted to circulate (pump) a lubricant from a lubricant reservoir ((117), (as shown in fig. 2)) to at least one nozzle (not shown) which is located inside the housing (101). The nozzle (not shown) in turn is adapted to direct the lubricant on the first rotatable unit (102), the second rotatable unit (104) and the shifting member (106) when the vehicle is operated in the four wheel drive mode. It is also within the scope of the invention to position the nozzle outside the housing (101).
[0045] The user interface unit (114) is adapted to communicate user input(s) about operating the vehicle in one of the two wheel drive mode or the four wheel drive mode (all-wheel drive mode) to the vehicle control unit (120). The user interface unit (114) is at least one of a switch, a button, a lever, a knob, a touchscreen, a user interface on vehicle infotainment system and an application present on a user device.
[0046] The vehicle speed sensor (118) is adapted to sense the vehicle speed and communicate the measured vehicle speed to the vehicle control unit (120). The vehicle control unit (120) is adapted to instruct the controller unit (112) to operate the vehicle in one of the two wheel drive mode and the four wheel drive mode based on at least one of input(s) from the user interface unit (114) and input(s) about at least one of operating parameters of the vehicle, operating terrain and weather conditions received through at least one of an electronic module and sensors provided to the vehicle. The vehicle control unit (120) is an electronic control unit.
[0047] The power source control unit (122) is in communication with the vehicle control unit (120). The power source control unit (122) is adapted to actuate or de-actuate the second power source (200B) in the four wheel drive mode or the two wheel drive mode respectively based on the instructions sent by the vehicle control unit (120) to the power source control unit (122). The power source control unit (122) is an electronic control unit for the second power source (200B).
[0048] The power source speed sensor (124) is adapted to sense operating speed of the output shaft (202S) of the second power source (200B) and communicates the measured speed of the output shaft (202S) of the second power source (200B) to the vehicle control unit (120).
[0049] FIG. 7 depicts a flow chart of a method (600) for engaging or disengaging at least one drivetrain (300B) with respect to a power source (200B) of an all-wheel drive vehicle (500). For the purpose of this description and ease of understanding, the method (600) is explained herein below with reference to dis-engaging the second drivetrain (300B) from the second power source (200B) when the all-wheel drive vehicle (500) is driven by the first power source (200A) through the first driveline (200A) in a two wheel drive mode. However, it is also within the scope of this invention to practice/implement the entire steps of the method (600) in a same manner or in a different manner or with omission of at least one step to the method (600) or with any addition of at least one step to the method (600) for in off-road vehicle or commercial vehicles or any other vehicles having dual drivetrains powered by a single power source or independently powered wheels without otherwise deterring the intended function of the method (600) as can be deduced from the description and corresponding drawings. At step, (602), the method (600) includes at least one of de-actuating and actuating, by a controller unit (112), each linear actuator (110A, 110B) based on instructions sent by a vehicle control unit (120) to the controller unit (112). At step (604), method (600) includes moving, by a movable member (110AM, 110BM) of each linear actuator (110A, 110B), a shifting member (106) through a shift fork (108) in a first direction in response to operating the linear actuators (110A, 110B) by the controller unit (112).
[0050] At step (606), the method (600) includes engaging, by the shifting member (106), a first rotatable unit (102) with a second rotatable unit (104) thereby engaging an output shaft (202S) of the second power source (200B) with an input shaft (302S) of a power transmission unit (302G) of the second drivetrain (300B) in response to moving, by the linear actuators (110A, 110B), the shifting member (106) in the first direction.
[0051] At step (601), the method (600) includes communicating, by at least one of an user interface unit (114), an electronic module and sensors provided to the vehicle, an input about operating the vehicle in a four wheel drive mode and input(s) about at least one of operating parameters of the vehicle, operating terrain and weather conditions to a vehicle control unit (120) respectively prior to the method step (602) of de-actuating and actuating each linear actuator (110A, 110B) by the controller unit (112).
[0052] The method (600) includes actuating the second power source (200B) by a power source control unit (122) based on signal sent by the vehicle control unit (120) to the power source control unit (122) when the vehicle control unit (120) receives at least one of input about operating the vehicle in the four wheel drive mode from the user interface unit (114) and inputs from the electronic module and sensors provided to the vehicle.
[0053] The method (600) includes, monitoring and communicating, by a vehicle speed sensor (118), speed of vehicle to the vehicle control unit (120); monitoring and communicating, by a power source speed sensor (124), speed of an output shaft (202S) of the second power source (200B) to the vehicle control unit (120); comparing, by the vehicle control unit (120), the operating speed of the output shaft (202S) of the second power source (200B) with the operating speed of the vehicle (500); and instructing, by the vehicle control unit 120), the controller unit (112) to operate the vehicle in the four wheel drive mode when the operating speed of the output shaft (202S) of the power source (200B) matches with the operating speed of the vehicle (500).
[0054] At step (608), the method (600) includes communicating by, at least one of the user interface unit (114), the electronic module and sensors provided to the vehicle, an input about operating the vehicle in a two wheel drive mode and input(s) about at least one of operating parameters of the vehicle, operating terrain and weather conditions to the vehicle control unit (120) respectively; and instructing the controller unit (112) by the vehicle control unit 120) to operate the vehicle in the two wheel drive mode based on at least one of inputs from the user interface unit (114), the electronic module and sensors provided to the vehicle.
[0055] At step (610), the method (600) includes at least one of de-actuating and actuating, by the control unit (112), each linear actuator (110B, 100A) based on instructions sent by the vehicle control unit (120) to the controller unit (112).
[0056] At step (612), the method (600) includes moving, by the movable member (110BM, 110AM) of each linear actuator (110B, 110A), the shifting member (106) through the shift fork (108) in a second direction in response to operating the linear actuators (110B, 110A) by the controller unit (112), where the second direction is opposite to the first direction in which the shifting member (106) is being moved by the linear actuators (110A, 110B).
[0057] At step (614), the method (600) includes disengaging, by the shifting member (106), the second movable member (104) from the first rotatable unit (102) thereby disengaging the output shaft (202S) of the second power source (200B) from the input shaft (302S) of the power transmission unit (302G) of the second drivetrain (300B) in response to moving, by the linear actuators (110B, 110A), the shifting member (106) in the second direction.
[0058] The technical advantages disclosed by the embodiments herein include reduction in drag torque of secondary drivetrain, prevention of permanent magnet motors generating unwanted current and reduction of higher thermal heat produced during towing of the vehicle or when the vehicle is operated in two wheel drive mode.
[0059] 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 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.