DESC:TECHNICAL FIELD
[0001] The present subject matter relates to a vehicle. More particularly, the present subject matter is a powertrain of a vehicle.

BACKGROUND
[0002] Over the last few years, with the induction of new powertrain technologies concomitantly, substantial attention has been paid to the reduction of pollutants emitted by vehicles. To this end, much attention has also been paid to the development of hybrid electric vehicles (HEV’s) for their optimal performance and durability. Importantly, the performance and durability are essential vehicle attribute that attracts customers to purchase the vehicle.
[0003] The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The present invention is described with reference to an exemplary embodiment of powertrain in a hybrid electric vehicle . The powertrain described here includes an electric motor. Such a powertrain can be installed in a two or three or multi wheeled vehicle. The same numbers are used throughout the drawings to reference like features and components. Further, the inventive features of the invention are set forth in the appended claims.
[0005] Non-limiting and non-exhaustive embodiments of the invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. It should be appreciated that the following figures may not be drawn to scale.
[0006] Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as a discussion of other potential embodiments or implementations of the inventive concepts presented herein. An overview of embodiments of the invention is provided below, followed by a more detailed description with reference to the drawings.
[0007] Figure 1. Illustrates a left side view of a two-wheeled or three wheeled vehicle (100), in accordance with an embodiment of the present subject matter.
[0008] Figure 2 illustrates a cut section view of a powertrain (212) across an A-A’ axis, where few parts are omitted from the figures.
[0009] Figure 3a illustrates a cut section view of the powertrain (212) an across B-B’ axis, where few parts are omitted from the figure, and an exploded view of a synchronizer sleeve assembly (201), as per embodiment, in accordance with one example of the present subject matter.
[00010] Figure 3b illustrates the transmission assembly (TA), where few parts are omitted from the figure, as per embodiment, in accordance with one example of the present subject matter.
[00011] Figure 4 illustrates a flow chart depicting methodology of controlling the powertrain in accordance with one example implementation of the present subject matter.
DETAILED DESCRIPTION
[00012] In the following description specific details are set forth to provide a thorough understanding of the embodiments. One skilled in the relevant art will recognize, however, that the techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.
[00013] Typically, design engineers strive to produce nonpolluting, elegant, easy to maintain transportation for the motoring public. The nonpolluting vehicles include electric vehicles. But, despite its many advantages, the limited range of the electric vehicle is a big letdown. Moreover, the inconvenience of recharging and the long recharge times reduces its appeal. However, the design engineers recognized that the good features of an engine could be combined with those of an electric machine to produce a hybrid vehicle. The hybrid vehicle includes the engine coupled to the electric machine to drive the vehicle. Both the engine and the electric machine are provided for the propulsion. Depending on degree of hybridization with the engine, the powertrain may comprise one or more electrical machines. The term “powertrain” refers to the electromechanical elements involved in the propulsion of the vehicle i.e. the engine, the electric machines, the running gear and control members for controlling these elements. The hybrid vehicles provide possible solution that combine the power of gasoline and electricity for propulsion but bring along the challenge of necessitating a compact powertrain within the same overall size of the vehicle. The challenge of such compact packaging and small engine design is further complex for a hybrid powertrain system especially in terms of the need to package elements of the vehicle in compact space.
[00014] To address the said issue, designers tend to provide a compact single stage reduction gear train, wherein a crankshaft of the engine is connected to a wheel of the two wheeled vehicle. However, a trade-off between torque requirement and speed is difficult in a single stage reduction gear train since at higher torque requirements the speed drops. Further, the hybrid vehicle has powertrain operating modes hence the starting behavior is different compared with a conventional vehicle. Typically, the operating modes include an eco-mode, a power mode and an engine mode configured to have different characteristics. These modes can be selected manually or automatically in a vehicle running state. However, it is observed that in the engine mode, in hybrid vehicles a large torque has to be provided by the engine within a very short time. More specifically, a very fast pulling up of the engine to a desired rotational driving speed is required especially in specific events. The events include gradient climbing, a sudden high load requirement or based on rider input command. During these events, it is observed that the lesser acceleration is provided by the engine with single speed reduction. Further, One of the drawbacks of the single speed reduction is limited speed and torque due to fixed reduction ratio in contrast with a Continuously variable transmission (hereinafter “CVT”). Therefore, there is a need to provide an efficient transmission assembly to deliver optimum torque based on vehicle operating conditions in said engine mode of the hybrid electric vehicle. However, in such a system described above, a high-capacity engine is required to be adapted to deliver more torque as per operating condition albeit at more weight and cost. In addition to the above, vehicle jerk being observed during switch over between two power sources which is undesirable.
[00015] To this end, there is a need to provide a transmission assembly for a hybrid electric vehicle that will meet the common requirements of the saddle type hybrid electric vehicle including compact size, low weight, low cost, high reliability, while overcoming all the above problems & other problems of the known art. The aforementioned disadvantages of the prior arts are solved by the present invention which provides an improved transmission assembly. The transmission assembly is advantageously used striving to meet customer expectations by providing a low cost and safe hybrid electric vehicle.
[00016] According to one embodiment, it is an object of the present invention to provide a powertrain, which is compact, and light in weight.
[00017] According to one embodiment, it is another object of the present invention to provide a powertrain being configured to reduce the jerk during switch over between power sources to ensure smooth riding experience.
[00018] According to one embodiment, it is yet another object of the present invention to provide a powertrain being configured to provide optimum torque in an engine mode.
[00019] According to the present subject matter, to attain the above-mentioned objectives, one aspect of the invention discloses a powertrain of a two or three wheeled hybrid electric vehicle and a method of controlling the powertrain. The powertrain comprising a traction motor, an engine and a transmission assembly. The traction motor being operatively connected to a drive wheel. The engine includes a crankshaft, and a centrifugal clutch member. The centrifugal clutch member being installed on said crankshaft. The centrifugal clutch member includes an input drive gear. The transmission assembly includes a drive shaft assembly, and a driven shaft assembly. The drive shaft assembly includes two or more drive gear. The drive gears being installed on a drive shaft. The drive gears include a first drive gear, a second drive gear, and a third gear. The input drive gear engages with one of said drive gear producing a primary reduction ratio. The driven shaft assembly includes two or more driven gears. The driven gears being rotatably installed on a driven shaft and said driven gears engages with fixedly installed said drive gears. The driven gears include a first driven gear, a second driven gear, and one or more synchromesh sleeve assembly. The synchromesh sleeve assembly being movably installed on said driven shaft and said synchromesh sleeve assembly being selectively engageable to one of said first driven gear and said second driven gear for transmitting rotational power between said drive shaft and said driven shaft. The synchromesh sleeve assembly engaging with said first primary driven gear produces a first predetermined reduction ratio, and said synchromesh sleeve assembly engaging with said second primary driven gear producing a second predetermined reduction ratio. The second predetermined reduction ratio being lesser than first predetermined reduction ratio.
[00020] In an embodiment, the synchromesh sleeve assembly being controlled by an actuating assembly. The actuating assembly includes one or more shifting fork, a gear shifting cam, and an actuator. The actuator being operatively coupled to said fork through said gear shafting cam to move said synchromesh sleeve assembly to engage with one of said driven gears selectively.
[00021] In an embodiment, the primary reduction ratio ranging from 1.1 to 4.
[00022] In an embodiment, the first reduction ratio ranging from 1.1 to 4.
[00023] In an embodiment, the second reduction ratio ranging from 1.1 to 4.
[00024] In an embodiment, the synchromesh sleeve assembly includes two or more synchromesh rings, one or more synchronizer sleeve, one or more synchronizer sleeve hub, two or more friction cones.
[00025] In an embodiment, the said friction cones include first friction cone, and a second friction cone, wherein said first friction cone being operatively coupled to said first driven gear, and said second friction cone being operatively coupled to said second driven gear.
[00026] In an embodiment, the synchronizer hub being fixedly attached to said driven shaft, and said synchronizer sleeve being movably installed on said synchronizer hub.
[00027] In an embodiment, the synchromesh sleeve assembly being electronically controlled by a control unit based on algorithm.
[00028] The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00029] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.
[00030] In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as one skilled in the art will appreciate, various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of the disclosure. Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosure. It is to be understood that the forms of disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Expressions such as “including”, “comprising”, “incorporating”, “consisting of”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.
[00031] Further, various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, connected, etc.) are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other.
[00032] Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification.
[00033] It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal hatches in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically specified.
[00034] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The invention will be described taking an electric/hybrid electric multi-wheeled vehicle as an example through the specification.
[00035] Figure 1. Illustrates a left side view of a two-wheeled vehicle (100) typically called a scooter, in accordance with an embodiment of the present subject matter. A frontward direction is indicated by an arrow F, and a rearward direction indicated by an arrow R provided in the top center of first figure. The vehicle is extending from the front direction to the rear direction along a vehicle longitudinal axis (Y-Y’). In an embodiment; the two-wheeled vehicle (100) of the present subject matter comprises a frame which is conventionally an under-bone chassis frame which provides a generally open central area to permit “step-through” mounting by a rider. The vehicle (100) illustrated, has a step-through type frame assembly (FA). The step-through type frame assembly (FA) includes a head tube (103), a down tube (104) and a sub frame (105). The frame assembly (FA) extends from a front portion F to rear portion R of the vehicle (100). Further, the frame assembly (FA) extends downward from the anterior portion of the head tube (103) and then extends to a rear portion of the vehicle (100) in inclined manner. The pair of side-tubes (not shown) extends rearwardly from the other end of the main tube (not shown) and supports vehicular attachments such as a seat assembly (115), fuel tank assembly (not shown), a utility box (not shown) and a pillion hand rest (122). In the rear end of the two wheeled vehicle (100) a rear lamp assembly (119) and a rear mud-guard/rear fender (116) is provided. The rear guard (116) having deflector (120). The head tube (103) supports a steering tube (not shown) and further connected to the front suspension system (117) at the lower end. A handlebar support member (not shown) is connected to an upper end of the steering tube and supports a handlebar assembly (121) which is having a mirror (124). Two telescopic front suspension systems (117) (only one is shown) support a front wheel (120). The upper portion of the front wheel (120) is covered by a front fender (112) mounted to the lower portion of the steering shaft (not shown). There is a front brake (not shown) and a rear brake (not shown) arranged on the front wheel (113) and a rear wheel (108) respectively. The rear wheel (108) is supported towards the rear side of the frame assembly (FA) by an internal combustion (IC) engine (106) which is horizontally coupled swingably to the rear of the frame assembly (FA) of the two wheeled vehicle (100) through a rear suspension system (118). A traction motor (107) integrated to the rear wheel (108). In a preferred embodiment, the traction motor (107) is hub mounted on the rear wheel (108). An on-board battery (125) (not shown) drives the traction motor (107). The internal combustion (IC) engine (106) is mounted on a swing arm (123), which is swingably connected to the down tube (104) using a toggle link. The frame assembly (FA) is covered by plurality of body panels, mounted on the frame assembly (FA) and covering the frame assembly (FA), including a front panel (102), a leg shield (109), an under-seat cover (110), and a left and a right side panel (111). Over the rear wheel (108) a body panel is disposed of to support the seat assembly (108). The internal combustion (IC) engine (106) transfers the drive to the rear wheel (108) as it is coupled to it. The internal combustion (IC) engine (106) comprises a transmission system, said system disposed leftward of the internal combustion (IC) engine (106) in the vehicle width direction.
[00036] A front fender (112) is covering the front wheel (113). A floorboard (114) is provided at the step-through space provide above the down tube (104). A seat assembly (115) is mounted to the sub frame (105). A rear fender (116) is covering at least a portion of the rear wheel (108) and it is positioned below the fuel tank (not shown). One or more rear suspension(s) (118) are provided in the rear portion of the vehicle (100) for comfortable ride. The vehicle (100) comprises of plurality of electrical and electronic components including a headlight (101), a rear lamp assembly (119), a transistor controlled ignition (TCI) unit (not shown), a starter motor (not shown).
[00037] Figure 2 illustrates a cut section view of the powertrain (212) across an A-A’ axis, where few parts are omitted from the figures for brevity. Fig 2 illustrates a rear portion of the two wheeled vehicle (100) illustrating the swingable internal combustion (IC) engine (106) in accordance with the embodiment of the present subject matter. A cylinder block (202) is covered by a deflection cover (203). The cylinder head (204) comprises intake valve (not shown) and outlet valve (not shown) which control the intake of air fuel mixture inside the combustion chamber, and controls the exit of exhaust gases after combustion respectively. The cylinder head (204) is covered by the cylinder head cover (205). A transmission assembly (TA) forms a part of the internal combustion (IC) engine (106) and is disposed on the rear portion of the internal combustion (IC) engine (106) and mounted so as to be disposed on right or left side of the two wheeled vehicle (100). The transmission assembly (TA) includes a drive shaft assembly (207), and a driven shaft assembly (208). The drive shaft assembly (207) includes two or more drive gears (207A, 207B, 207C). The drive gears (207A, 207B, 207C) being installed on a drive shaft (207D). The drive gears (207A, 207B, 207C) include a first drive gear (207A), a second drive gear (207B) and a third drive gear (207C). As per an embodiment, the drive shaft (207D) being fully splined (as shown in figure 3b) and the drive gears (207A, 207B, 207C) being fixedly installed on the drive shaft (207D) using circlips (not shown). Further, the driven shaft assembly (208) includes two or more driven gears (208A, 208B) and a synchromesh sleeve assembly (201). The driven gears (208A, 208B) being rotatably installed on a driven shaft (208C). The driven gears (208A, 208B) engage with the fixedly installed second and third drive gears (207B, 207C). The driven gears (208A, 208B) include a first driven gear (208A), a second driven gear (208B). During operation, the burning of air fuel mixture occurs in the cylinder block (202). The forces generated due to combustion of air fuel mixture is transferred to a piston (206) which is capable of reciprocating inside the cylinder block (202), and this reciprocating motion is transferred to rotary motion of the crankshaft (210) though a connecting rod (213) by the slider crank mechanism. A spring-loaded centrifugal clutch (209) is fixedly attached to the crankshaft (210) using fastening means. The centrifugal clutch (209) ensures that at low to idle speeds the power transmission from the internal combustion (IC) engine (106) is disengaged to the rear wheel (108) (as shown in fig. 1) as spring loaded centrifugal shoe unit is fixedly attached to the crankshaft (210) and capable of expanding and engaging with an outer hub (209A) on rotation of the crankshaft (210) only beyond a predetermined speed thereby rotating an input drive gear (211). The input drive gear (211) is engaged with the first driver gear (207A) and is welded with the outer hub (209A) known as drum. On attaining certain revolutions per minute (rpm) the input drive gear (211) rotates the first drive gear (207A) of the drive shaft assembly (207) producing a primary reduction ratio. As per an embodiment, the primary reduction ratio ranges from 1.1 to 4. Torque transfer from said first drive gear (207A) rotates the first drive shaft (207D) which in turn rotates the drive gears (207B, 207C). The driven gears (208A, 208B) being engaged with the drive gears (207B, 207C) respectively to transfer the torque and rotate said driver gears (208A, 208B). Further, the synchromesh sleeve assembly (201) being slidably installed on said driven shaft (208C) and rotatably engaged with the driven shaft (208C). The synchromesh sleeve assembly (201) being selectively engageable to one of said first driven gear (208A) and said second driven gear (208B) for transmitting rotational power between said drive shaft (207D) and said driven shaft (208C). In a first selection, the synchromesh sleeve assembly (201) engaging with said first driven gear (208A) produces a first predetermined reduction ratio. As per an embodiment, the first reduction ratio ranging from 1.1 to 4. Further, as per a second engagement selection, the synchromesh sleeve assembly (201) engaging with said second driven gear (208B) producing a second predetermined reduction ratio. As per an embodiment, the second predetermined reduction ratio being lesser than first predetermined reduction ratio. As per an embodiment, the second reduction ratio ranging from 1.1 to 4.
[00038] Figure 3a illustrates a cut section view of the powertrain (212) across B-B’ axis, where few parts are omitted from the figure, and an exploded view of the synchronizer sleeve assembly (201), as per embodiment, in accordance with one example of the present subject matter is depicted. Figure 3b illustrates the transmission assembly (TA), where few parts are omitted from the figure, as per embodiment, in accordance with one example of the present subject matter. For the sake of brevity, Figure 3a, and Figure 3b will be discussed together. The synchromesh sleeve assembly (201) includes two synchromesh rings (201CA, 201CB), a synchronizer shifting sleeve (201B), and a synchronizer sleeve hub (201A). The synchromesh rings (201CA, 201CB) includes a first synchromesh ring (201CA) and a second synchromesh ring (201CB). The first synchromesh ring (201CA) being operatively coupled to a first friction cone (201DA), and said second synchromesh ring (201CB) being operatively coupled to a second friction cone (201DB). The first friction cone (201DA) and the second friction cone (201DB) being coupled to the first driven gear (208A) and the second driven gear (208B) respectively thereby enabling selective transfer of torque from the first synchromesh ring (201CA) to the driven shaft (208C) and from the second synchromesh ring (210CB) to the drive shaft (208C) resulting in the first predetermined reduction ratio and the second predetermined reduction ratio. The synchronizer hub (201A) being fixedly mounted on said driven shaft (208C), and the synchronizer shifting sleeve (201B) slidably installed on said synchronizer hub (201A). The synchronizer shifting sleeve (201B) being operated by an actuating assembly (304). The actuating assembly (304) includes an actuator (303), a gear shifting cam (302), and a shifting fork (301). One end of the shifting fork (301) being coupled to the gear shifting cam (302) and another end being coupled to said synchronizer shifting sleeve (201B). Importantly, the actuator (303) being operatively coupled to said gear shifting cam (302). The gear shifting cam (302) converts rotatory motion into linear motion based upon which shifting fork (301) selectively engages with the first driven gear (208A) and the second driven gear (208B). As per an embodiment, the selective engagement is based on vehicle state operating parameters.
[00039] Figure 4 illustrates a flow chart depicting methodology of controlling the powertrain in accordance with one example implementation of the present subject matter, wherein the vehicle state parameter value includes vehicle speed. The process starts with step (101) where a control unit (not shown) receives a ride mode change input from the user during vehicle running or stationary condition. Subsequent to step (101), determining as a first determination whether vehicle is operating in an engine mode. At step (103), based on affirmative determination at step (102), determining as a second determination, whether vehicle speed being lesser than or equal to a predetermined vehicle speed. As per an embodiment, the predetermined vehicle speed ranges from 1 to 50 kmph. At step (104), based on affirmative determination at step (103), said control unit generates an output command wherein the synchronizer sleeve assembly placed between a first driven gear and a second driven gear, engages with a first driven gear to transfer power and drive the vehicle with the first predetermined reduction ratio alternatively also referred as a first predetermined transmission ratio. Further, based on negative determination at step (103), at step (105), said control unit generates an output command, wherein said synchronizer sleeve assembly engages with a second driven gear to transfer power and drive the vehicle with the second predetermined reduction ratio also referred as a second predetermined transmission ratio. Importantly, the diameter of first driven gear being larger than diameter of said second driven gear.
[00040] According to the above architecture, one of the primary efficacies of the present invention is the optimum torque and better acceleration being provided in the required zone during initial pickup in the engine mode as synchromesh sleeve assembly establish a high torque forward driving path through the first drive gear and the first driven gear and its first predetermined reduction ratio. Further, after attaining predetermined speed the synchromesh sleeve assembly establishes high speed forward driving path through second drive gear and second driven gear and its second predetermined reduction ratio. This provides high speed. Additionally, the powertrain provides smooth and automatic shifting of gears without any manual intervention due to use of synchromesh sleeve assembly, control unit and the actuator. This improves the riding experience of the customers and reduces fatigue.
[00041] According to the above architecture, one of the primary efficacies of the present invention is the reduction in jerk during switching of power sources due to closer reduction ratios.
[00042] The above-described embodiments, and particularly any “preferred” embodiments, are possible examples of implementations and merely set forth for a clear understanding of the principles of the invention. It will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention.
List of Reference


TA Transmission assembly
100 vehicle
101 Head light
102 Front panel
103 Head tube
104 Down tube
105 Sub frame
106 Engine
107 Traction motor
108 rear wheel
109 Leg shield
110 Under seat cover
111 a left and right side panel
112 Front fender
113 Front wheel
114 Floor board
115 Seat assembly
116 Rear fender
117 Front suspension
118 rear suspension
119 Rear lamp assembly
120 Deflecter
121 Handle bar assembly
122 Pillion hand rest
123 Swing arm
124 Mirror
125 On board battery
201 Synchronizer sleeve assembly
201A Synchronizer hub
201B Synchronizer shifting sleeve
201CA First Synchronizer ring
201CB Second synchronizer ring
201DA First friction cone
201DB Second friction cone
202 Cylinder block
203 Deflection cover
204 Cylinder head
205 Cylinder head cover
206 Piston
207 Drive shaft assembly
207A First drive gear
207B Second drive gear
207C Third drive gear
207D Drive shaft
208 Driven shaft assembly
208A First driven gear
208B Second driven gear
208C Driven shaft
209 Centrifugal clutch
209A Outer hub
210 Crankshaft
211 Input drive gear
212 Powertrain
213 Connecting rod
301 Shifting fork
302 Gear shifting cam
303 Actuator
304 Actuating assembly

,CLAIMS:We Claim:
1. A powertrain (212) for a two or three wheeled vehicle (100), said powertrain (212) comprising:
a traction motor (107), said traction motor (107) being operatively connected to a rear wheel (108);
an engine (106), said engine (106) includes
a crankshaft (210), and
a centrifugal clutch member (209) being installed on said crankshaft (210), said centrifugal clutch member (209) includes
an input drive gear (211); and
a transmission assembly (TA), said transmission assembly (TA) includes
a drive shaft assembly (207), wherein said drive shaft assembly (207) includes
two or more drive gear (207A, 207B, 207C), said drive gears (207A, 207B, 207C) being fixedly installed on a drive shaft (207D), said drive gears (207A, 207B, 207C) include
a first drive gear (207A),
a second drive gear (207B), and
a third gear (207C),
wherein said input drive gear (211) engages with one of said drive gear (207A, 207B, 207C) for producing a primary reduction ratio,
a driven shaft assembly (208), wherein said driven shaft assembly (208) includes
two or more driven gears (208A, 208B), said driven gears (208A, 208B) being rotatably installed on a driven shaft (208C) and said driven gears (208A, 208B) engages with said drive gears (207B, 207C), wherein said driven gears (208A, 208B) includes
a first driven gear (208A),
a second driven gear (208B),
one or more synchromesh sleeve assembly (201),
wherein said synchromesh sleeve assembly (201) being slidably installed on said driven shaft (208C) and rotatably engaged with said driven shaft (208C), said synchromesh sleeve assembly (201) being capable of selectively engaging one of said first driven gear (208A) and said second driven gear (208C) for transmitting rotational power between said drive shaft (207D) and said driven shaft (208C),
wherein said synchromesh sleeve assembly (201) selectively engaging with said first driven gear (208A) produces a first predetermined reduction ratio, and said synchromesh sleeve assembly (201) selectively engaging with said second primary driven gear (208B) producing a second predetermined reduction ratio, and
wherein said second predetermined reduction ratio being lesser than first predetermined reduction ratio.

2. The powertrain (212) for a two or three wheeled vehicle (100) as claimed in claim 1, wherein said synchromesh sleeve assembly (201) being operated by an actuating assembly (304), said actuating assembly (304) includes
one or more shifting fork (301),
a gear shifting cam (302), and
an actuator (303), wherein said actuator (303) being operatively coupled to said shifting fork (301) through said gear shifting cam (302) for sliding said synchromesh sleeve assembly (201) and thereby engaging with one of said driven gears selectively (208A, 208B).
3. The powertrain (212) for a two or three wheeled electric vehicle (100) as claimed in claim 1, wherein said primary reduction ratio ranging from 1.1 to 4.
4. The powertrain (212) for a two or three wheeled vehicle (100) as claimed in claim 1, wherein said first reduction ratio ranging from 1.1 to 4.
5. The powertrain (212) for a two or three wheeled vehicle (100) as claimed in claim 1, wherein said second reduction ratio ranging from 1.1 to 4.
6. The powertrain (212) for a two or three wheeled vehicle (100) as claimed in claim 1, wherein said synchromesh sleeve assembly (201) includes two or more synchromesh rings (201CA, 201CB), one or more synchronizer sleeve (201B), one or more synchronizer sleeve hub (201A), and two or more friction cones (201DA, 201DB).
7. The powertrain (212) for a two or three wheeled vehicle (100) as claimed in claim 6, wherein said friction cones (201DA, 201DB) includes a first friction cone (201DA), and a second friction cone (201DB), wherein said first friction cone (201DA) being operatively coupled to said first driven gear (208A), and said second friction cone (201DB) being operatively coupled to said second driven gear (208B) for enabling selective power transmission.
8. The powertrain (212) for a two or three wheeled vehicle (100) as claimed in claim 6, wherein said synchronizer hub (201A) being fixedly attached to said driven shaft (208C), and said synchronizer shifting sleeve (201B) slidably installed on said synchronizer hub (201A) and rotatably engaged with the driven shaft (208C).
9. The powertrain (212) for a two or three wheeled vehicle (100) as claimed in claim 1, wherein said synchromesh sleeve assembly (201) being electronically controlled by a control unit based on algorithm.
10. A method of controlling a powertrain (212) for a vehicle (100), said method comprising steps of :
At step 101, receiving ride mode change inputs, by a control unit,
At step 102, determining as a first determination whether vehicle is operating in a predetermined mode,
At step 103, based on affirmative determination at step 102, determining as a second determination, whether vehicle state operating parameter being lesser than or equal to predetermined state operating parameter value,
At step 104, based on affirmative determination at step 103, said control unit generating an output command wherein a synchronizer sleeve assembly between a first driven gear and a second driven gear, configured to engage with a first driven gear.
11. The method of controlling said powertrain as claimed in claim 10, wherein said predetermined mode includes an engine mode.
12. The method of controlling a powertrain as claimed in claim 10, wherein based on a negative determination at step 103, at step 105, said control unit generates an output command, wherein said synchronizer sleeve assembly engages with a second driven gear to transfer power with a second predetermined reduction ratio.
13. The method of controlling said powertrain as claimed in claim 10, wherein said predetermined state operating parameter values includes vehicle speed ranging from 1 to 50 kmph.
14. The method of controlling a powertrain as claimed in claim 10, wherein said diameter of first driven gear being larger than diameter of said second driven gear.
15. A vehicle as claimed in any of the preceding claims being a straddle type hybrid electric two wheeled vehicle or a three wheeled vehicle.