Claims:We Claim:
1. An engine assembly (102) comprising of
a crankcase (206), said crankcase (206) extending rightward and leftward in a lateral direction (X-X’) of the longitudinal axis;
a forced air cooling system (111) disposed on said engine assembly (102) to cover at least a portion of an engine (104), said forced air cooling system (111) comprising:
an air introduction part (111a) enclosing a cooling fan (301) and capable of directing air to a cylinder unit shroud part (111b); and
one or more piece cowl (309), said piece cowl (309) is disposed between said air introduction part (111a) and said crankcase (206) to enable leak proof cooling of the engine assembly.
2. The engine assembly (102) as claimed in claim 1, wherein said crankcase (204) accommodates an detection means connected to a control system through plurality of wires, said wires are protected by a detection means grommet (308) said detection means grommet (308) is positioned in a detection means grommet slot (401) provided in the crankcase (206a) such that a portion of the detection means grommet (308) is in contact with a portion of the piece cowl (309).

3. The engine assembly (102) as claimed in claim 1, wherein said piece cowl (309) and detection means (307) are detachably attached to the crankcase (206) using attaching means such that piece cowl (309) overlaps a portion of the detection means (307) when viewed from the top.

4. The engine assembly (102) as claimed in claim 1, wherein said piece cowl (309) is configured to predetermined shape in order to mate with the inner fan shroud (111aa) and a RH crankcase (206a) in a stable, rigid and leak proof manner, said predetermined shape includes substantially L –shape piece cowl (309).

5. The engine assembly (102) as claimed in claim 1, wherein said piece cowl (309) comprises a base member (309a) of predetermined thickness, said base member (309a) has a side surface(309aa), a top surface (309ab) and a bottom surface (309ac).

6. The engine assembly (102) as claimed in claim 5, wherein said bottom surface(309ac) is configured to have a pair of attachment portion (309aca) and at least one of said attachment portion (309aca) includes one or more opening (309acaa) adapted to receive the attaching means (402).

7. The engine assembly (102) as claimed in claim 5, wherein front end of the base member (309a) is configured to have a hugging profile (309ad) which is formed to connect with a portion of the crankcase (206).

8. The engine assembly (102) as claimed in claim 5, wherein rear end of said base member (309a) includes an inclined portion (309ae), said inclined portion (309ae) is extending in the lateral direction (X-X’) of the vehicle (100) and bends downwardly in a longitudinal direction (Y-Y’) of the vehicle (100).

9. The engine assembly (102) as claimed in claim 5, wherein said side surface (309aa) includes a plurality of stepped portion (309aaa) profiled to butt with a portion of said crankcase (206).

10. The engine assembly (102) as claimed in claim 5, wherein said top surface (309ab) is configured to have a semicircular projection (309aba) adapted to butt with a portion of said crankcase (206). , Description:TECHNICAL FIELD
[0001] The present subject matter relates to a multi-fuel vehicle platform. More particularly, to an engine assembly for a vehicle

BACKGROUND
[0002] An internal combustion (IC) engine (hereinafter “engine”) converts thermal energy obtained from burning of a fuel with air into mechanical energy, which can be employed to do a wide variety of mechanical work. It is used to provide motive force for movement of an automobile. The main parts of the engine include a cylinder head, a reciprocating piston on a cylinder block and a connecting rod which connects the piston to the reciprocating crankshaft. During operation of the engine, the burning of fuel and oxidizer occurs in a combustion chamber interposed between the cylinder head and cylinder block and transfers mechanical energy to the reciprocating piston. This operation generates lot of thermal energy in and around the cylinder head and cylinder block. This thermal energy increases the temperature around the cylinder head and the cylinder block and the atmospheric air surrounding it. Hence, it is necessary to cool the cylinder head, the cylinder block, its associated components and the surrounding air.

BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The detailed description is explained with reference to an embodiment of forwardly inclined single cylinder engine assembly in saddle type vehicle with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0004] Figure 1 illustrates an isometric view of an engine assembly (102) in a vehicle, in accordance with one example implementation of the present subject matter.
[0005] Figure 2a illustrates a side view of the engine assembly (102) including an air filter assembly (108) assembled on the engine in the vehicle (101), in accordance with one example implementation of the present subject matter.
[0006] Figure 2b illustrates a side view of the engine assembly (102), in accordance with one example implementation of the present subject matter where few parts are omitted from the figures.
[0007] Figure 3 illustrates an exploded view of the forced air cooling system (111) and a cooling fan (301) mounted on the engine (104).
[0008] Figure 4a illustrates a top cut section view of the engine assembly (102) across A-A’ axis and a localized side view of engine assembly (102) where few parts are omitted from the figure.
[0009] Figure 4b illustrates an enlarged localized exploded view of the engine assembly (102).
[00010] Figure 5 illustrates the piece cowl (309).

DETAILED DESCRIPTION
[00011] Various features and embodiments of the present subject matter here will be discernible from the following further description thereof, set out hereunder. According to an embodiment, an internal combustion engine (IC) described here operates in four cycles. Such an IC engine is installed in a step through type two wheeled vehicle. It is contemplated that the concepts of the present invention may be applied to other types of vehicles such as a three-wheeled vehicle wherein the IC engine is enclosed within the spirit and scope of this invention. Further "front" and "rear", and "left" and "right" referred to in the ensuing description of the illustrated embodiment refer to front and rear, and left and right directions as seen from a rear portion of a vehicle and looking forward. The detailed explanation of the constitution of parts other than the present subject matter which constitutes an essential part has been omitted at suitable places.
[00012] An engine comprises of a cylinder head, a reciprocating piston inside a cylinder block located adjacent to a cylinder head, a rotatable crankshaft to transfer mechanical energy to a transmission system and a connecting rod transferring energy imparted to the reciprocating piston to the rotatable crankshaft. During operation of the engine, the burning of air fuel mixture occurs in a combustion chamber interposed between the cylinder head and the cylinder block. This operation generates lot of thermal energy in and around the cylinder head and the cylinder block. This thermal energy increases the temperature of the cylinder block, the cylinder head and the atmospheric air surrounding it. If this thermal energy is not dissipated, it may result in the cylinder block and the cylinder head failure in form of seizure, excessive wear and tear, etc. Additionally, due to high temperatures, the film of the lubricating oil on the sliding surface of the cylinder block may get oxidized, thus producing carbon deposits on the internal surface of the cylinder block. This may result in seizure of the reciprocating piston. Also, large temperature differences may lead to a distortion of the engine components due to the thermal stresses which are set up. It is also seen that higher temperatures result in lower volumetric efficiency of the engine. Hence, it is necessary to cool the cylinder block, the cylinder head, its associated components and the surrounding air through a cooling system.
[00013] The cylinder head and the cylinder block have critical heat zones where the temperature around these zones is greater than its surrounding areas. Most of the thermal energy generated in the combustion chamber is expelled in the form of hot exhaust gases. The exhaust gases are expelled through the exhaust pipe, hence the zone around an exhaust gas pipe connection has greater temperatures and this thermal energy should be removed efficiently.
[00014] Generally, for a swinging type engine, a cooling system is used to perform engine cooling. In active cooling systems, atmospheric air is drawn inside the cooling system from the outer atmosphere through an inlet by using a cooling fan. The rotation of the cooling fan is integrated to the rotation of the crankshaft. A shroud assembly surrounding the cylinder head, cylinder block and the engine is provided to enable atmospheric air circulation, and thereby cooling all the components. Typically, the heat generated due to combustion is conducted to fins on the cylinder head and when the air flows over the fins, heat gets dissipated to air. The design of shroud assembly is critical as they not only create an air path to guide the air flow while cooling, but also help in efficient performance of cooling system through suitable shroud shape and design. Shroud assembly geometry design is critical to achieve better guidance over its inner surfaces and one can enhance the design to obtain maximum utilization of cooling capacity of flowing air. The shroud assembly design also enables variation of parameters of air flow rate and air velocity as extreme care must be taken to ensure the engine is cooled at all desired conditions of operations.
[00015] In the engine of such a multi wheeled compact vehicle as described above, the layout of the engine is a very important criterion as space availability to accommodate various elements is constrained due to the small size of the engine. There are various sub systems which form a part of the overall working of the engine. Such systems include transmission system, lubrication system, electrically operated actuators and sensors etc. Accommodating all these systems inside the engine layout is difficult and there may arise situations where accommodating the cooling system becomes challenging when peripheral systems like EFI, SAI, etc. are also disposed within.
[00016] In the engine layout for the above multi wheeled vehicle, a magneto assembly is mounted rightward of the crankshaft and located right of the crankcase. Other essential components are disposed inside the engine thus defining the engine layout.
[00017] Further, the swinging type engine has a lot of sub-systems which monitor various parameters and are actively controlled by a control system. It uses various sensors, actuators, motors and controllers to control the engine operation based on various inputs received such as throttle position and vehicle speed. These actuators and motors also need to be accommodated inside the engine. To connect with control system, multiple wires running in and out of the engine assembly leading to dangling movement of the wiring harness. But, constant movement of wires can eventually erode the wire covering and lead to a short circuit. To solve this problem, a rubber grommet is installed where wires come in contact with metal. Generally, the diameter of the hole in the grommet is large enough to accommodate the wire. The hole or slot in the engine assembly must be just enough to accommodate the groove in the grommet and groove in the grommet must be wide enough to fit the thickness of the material the hole or slot is cut in. Additionally, the fuel ignition timing is an important factor having great influence on the engine performance. Usually, the fuel ignition timing is detected by a pulsar coil or similar detection means. The pulsar coil is so disposed that it faces a magnet provided on the outer periphery of a magneto or ISG (Integrated Starter Generator) connected to a crankshaft, for instance, and the fuel ignition timing is obtained according to a magnet detection signal, i.e., a crankshaft rotation detection signal, from the pulsar coil. The pulsar coil signal is transmitted to the control system for deciding the fuel ignition timing. The pulsar coil is mounted to the crankcase of the engine such that plurality of wires running in and out from the engine is connected to the control system. To protect the wires, the grommet is pushed from the edge of the crankcase into a grommet slot provided in the crankcase. However, to properly mate the shroud assembly is a challenge due to manufacturing constraints and complicated design. The manufacturing constraints include an undulating contour in the shroud assembly. Because of above constraints the shroud assembly often does not perfectly mate with the crankcase to which it is attached whereby spacing often results there between. It becomes more complicated when separate component i.e. crankcase which is machined within certain tolerance is assembled together with shroud assembly of different materials. Hence it requires lot of precision and complex manufacturing controls and tooling infrastructure. In addition to that there is relative motion between the engine and the shroud assembly since the shroud assembly moves with the engine when the engine rolls, shakes or vibrates. This further movement of the engine results in increased gap and negatively affects the alignment of the grommet and retention of the grommet. The dimensional stability of grommet is impaired by the increased gap between crankcase and the shroud assembly. Therefore, there is a need for an improved engine cooling cum stable wiring harness guide layout that is simple, robust while overcoming all problems cited above and other problems of known art.
[00018] Due to above problem and use of the cooling system to cool the cylinder block and cylinder head in such engine layout, the present subject matter aims to address the above drawbacks by providing one or more piece cowl configured to secure dimensional stability of the grommet wherein a cooling fan is fixedly mounted on a crankshaft of the engine in a layout where magneto or Integrated starter generator (hereinafter “ISG”) assembly is located on one of the right or left side and a grommet is positioned on the same side as that of the cooling fan in order to guide the wires. To achieve this aim, the solution proposed is simple in construction.
[00019] With the above design, the following advantages can be obtained such as improved air circulation due to elimination of leakage through large gap, and avoid use of additional mounting provisions.
[00020] According to the present subject matter to attain the above mentioned objectives, a first characteristic of the present invention is the engine assembly comprising of a crankcase, said crankcase extending rightward and leftward in a lateral direction of the longitudinal axis. A forced air-cooling system disposed on said engine assembly to cover at least a portion of an engine. The forced air-cooling system comprising: an air introduction part enclosing a cooling fan and capable of directing air to a cylinder unit shroud part. One or more piece cowl is disposed between said air introduction part and the crankcase.
[00021] In addition to the first characteristic, a second characteristic of the present invention is an engine assembly vehicle wherein said crankcase accommodates an detection means connected to a control system through plurality of wires, said wires are protected by a robust and stable detection means grommet, said detection means grommet is positioned in a detection means slot provided in the crankcase such that a portion of the detection means grommet is contact with a portion of the piece cowl.
[00022] In addition to the first characteristic, a third characteristic of the present invention is an engine assembly vehicle, wherein said piece cowl and detection means are detachably attached to the crankcase using fastening means like fasteners such that piece cowl overlaps a portion of the detection means when viewed from the top.
[00023] In addition to the first characteristic, a fourth characteristic of the present invention is an engine assembly vehicle wherein said piece cowl is configured to predetermined shape in order to properly mate with the inner fan shroud and a RH crankcase, said predetermined shape includes substantially L –shape piece cowl.
[00024] In addition to the first characteristic, a fifth characteristic of the present invention is an engine assembly vehicle, wherein said piece cowl comprises a base member of predetermined thickness, said base member has a side surface, a top surface and a bottom surface.
[00025] In addition to the first characteristic and fifth characteristic, a sixth characteristic of the present invention is an engine assembly vehicle, wherein said bottom surface is configured to have a pair of attachment portion and at least one of said attachment portion includes one or more opening adapted to receive the fastening means.
[00026] In addition to the first characteristic and fifth characteristic, a seventh characteristic of the present invention is an engine assembly vehicle, wherein front end of the base member is configured to have a hugging profile which is formed to connect with a portion of the crankcase.
[00027] In addition to the first characteristic and fifth characteristic, an eighth characteristic of the present invention is an engine assembly vehicle, wherein rear end of said base member includes an inclined portion, said inclined portion is extending in lateral direction of the vehicle and bends downwardly in the longitudinal direction of the vehicle.
[00028] In addition to the first characteristic and fifth characteristic, a ninth characteristic of the present invention is an engine assembly vehicle, wherein said side surface includes a plurality of stepped portion profiled to butt with a portion of said crankcase.
[00029] In addition to the first characteristic and fifth characteristic, a tenth characteristic of the present invention is an engine assembly vehicle, wherein said top surface is configured to have a semicircular projection adapted to butt with a portion of said crankcase.
[00030] 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.
[00031] 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.
[00032] 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.
[00033] 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.
[00034] 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.
[00035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[00036] Figure 1 illustrates a perspective view of an engine assembly (102) in a vehicle (101), in accordance with one example implementation of the present subject matter. As shown, the vehicle (101) includes the engine assembly (102) and a muffler (103) to route exhaust air from the engine assembly (102). The engine assembly (102) includes an engine (104). The engine (104) is mounted on a swing arm (105), which is swingably connected to a frame assembly (not shown). A rear wheel (106) is rotatably supported by the swing arm (105). One or more rear suspension(s) (107) are connecting the swing arm (105) at an angle, to sustain both the radial and axial forces occurring due to wheel reaction. The engine assembly (102) is operatively connected to one or more air filter assembly (108).The air filter assembly (108) draws air inside and filters the same, and it is further throttled by a throttle body (109) before being mixed with fuel by a fuel injector (not shown) and supplied to the engine (104) by an intake pipe (110). The engine (104) produces useful power by burning a mixture of fuel and air. Further, a forced air cooling system (111) is operatively connected to the engine assembly (102). The forced air cooling system (111) comprises of an air introduction part (111a) which guides air to the engine (104). The air introduction part (111a) comprises an inner fan shroud (111aa), and an outer fan shroud (111ab). As per one implementation, the muffler (103) may route circulated exhaust gas away from the engine assembly (102). In one example, at the front side, the outer fan shroud (111ab) may have a slanting profile, such that the length of the outer fan shroud (111ab) at the side towards the muffler (103) (facing the ground) is greater than the length of the outer fan shroud (111ab) at the side away from the muffler (103) (away from the ground). As a result, the ambient air from the atmosphere enters the outer fan shroud (111ab) from the front direction (F) of the vehicle (101) and not from over the muffler (103). As a result, ambient air from the atmosphere enters the outer fan shroud (111ab) rather than heated air that has passed over the muffler (103).
[00037] Figure 2a illustrates a side view of the engine assembly (102), in accordance with one example implementation of the present subject matter where few parts are omitted from the figures. The vehicle (101) is extending from the front direction (F) to the rear direction (R) along the vehicle longitudinal axis (F-R). A starter motor (201) has a pinion gear (not shown) which rotates a back plate of one way clutch (212) through an idler gear (202) via ring gear (203). The back plate of one way clutch (212) enables the rotation of a crankshaft (204) for cranking the engine (104). The idler gear (202) is aligned and positioned with a help of an idler pin (205). The idler pin (205) is mounted on a crankcase (206). Further, the fit between both the parts i.e. idler pin (205) and idler gear (202) is clearance fit to allow the idler pin (205) to rotate freely over an idler pin axis and also to allow lubrication oil to go in between both the parts. The idler pin (205) is supported by an idler pin bracket (207). The idler pin bracket (207) is mounted on the crankcase (206). Further, the idler pin bracket (207) is positioned and oriented in the crankcase (206) due to at least two dowels (208). Because of above architecture, the proper alignment and location of the idler gear (202) with respect to the pinion gear (not shown) and the ring gear (203) is maintained which ensures low noise electric start system.

[00038] Figure 2b illustrates a side view of the engine assembly (102) including an air filter assembly (108) assembled on the engine in the vehicle (101), in accordance with one example implementation of the present subject matter. The air filter assembly (108) includes an air cleaner (108a). The air cleaner (108a) has been mounted on a cover crankcase (209) of the engine (104) using at least two mounting points (210a, 210b), such that the air device (108a) is mounted in an angular position with respect to a vertical-longitudinal plane (Up - Y) such that it will have clearance with both side panels (not shown) and the rear wheel (106) (as shown in figure 1). The first mounting point (210a) of the air cleaner (108a) is provided above the cover crankcase (209) of the engine (104). Further, the second mounting (210b) is provided on an elongated leg (211) of the cover crankcase (209) to mount the air cleaner (108a). Because of above architecture it is easy to manufacture as all the machining operation to mount the air filter assembly (108) can performed on single part i.e. cover crankcase (209). Further, it is easy to service the air filter assembly (108) as both mounting points are provided on the cover crankcase (209) on a single side.
[00039] Figure 3 illustrates an exploded view of the forced air cooling system (111) and a cooling fan (301) mounted on the engine (104). The engine (104) comprises a cylinder block (303) on which a cylinder head (302) is disposed forming a combustion chamber (not shown) at the junction. In this embodiment the forced air cooling system (111) comprises of the air introduction part (111a) and a cylinder unit shroud part (111b). The air introduction part (111a) encloses a cooling fan (301) and draws air from the atmosphere and introduces it to the cylinder unit shroud part (111b) which circulates the air around the cylinder head (302) and the cylinder block (303). The cylinder unit shroud part (111b) is covering the cylinder unit (302, 303) forming an air path between faces of the cylinder unit (302, 303). To further seal the air leakages from around the cylinder unit shroud part (111b), rubber grommets (304a, 304b) are provided at two locations. A first rubber grommet (304a) is provided between intake pipe (110) and the cylinder shroud part (111b).The second rubber grommet (304b) between inner fan shroud (111aa) and cylinder shroud part (111b). These grommets (304a, 304b) prevent leakage of air from the engine assembly (102).The inner fan shroud (111aa) is mounted on the engine (104) through fasteners (305a) mounted through bosses (206aa, 111aab) present on the RH Crankcase (206a) and the inner fan shroud (111aa) respectively. The inner fan shroud (111aa) acts as a cover over the internal components of the engine (104) supported by the RH Crankcase (206a). The inner fan shroud (111aa) has a large central opening (111aaa) towards its base to accommodate the outer rotor of a magneto assembly or ISG (306) inside the central opening (111aaa). The assembly is configured such that, when the inner fan shroud (111aa) is mounted on the RH Crankcase (206a), the flat radial surface of the outer rotor of the magneto assembly or ISG (306) is just exposed outside the inner fan shroud (111aa). A detection means (307) is located near the inner side of the RH Crankcase (206a) and on the outer periphery of the outer rotor magneto assembly or ISG (306).The plurality of wires (not shown) running in and out from the engine assembly (102) connected to a control system (not shown) are protected by a detection means grommet (308).The detection means grommet (308) is provided in the RH Crankcase (206a). A piece cowl (309) is disposed between the RH Crankcase (206a) and the inner fan shroud (111aa).During assembly of the engine (104), the inner fan shroud (111aa) is mounted on the RH Crankcase (206a) which acts as a cover to other parts of the engine (104) and encloses them leaving a small part of the crankshaft (204) exposed. The magneto assembly or ISG (306) is subsequently mounted on the crankshaft (204) through the large central opening (111aaa). The outer rotor of the magneto assembly or ISG (306) comprises plurality of holes with internally tapped threads which are used to mount the cooling fan (301) on it.
[00040] The outer fan shroud (111ab) has a profile being a mirror image of the inner fan shroud (111aa) and is configured to cover the inner fan shroud (111aa) so that they abut and mate perfectly. This connection is achieved by bringing together both and securing the outer fan shroud (111ab) by fasteners (305b) and by providing snap-fit connection towards the upper portions of the outer fan shroud (111ab) and inner fan shroud (111aa). The outer fan shroud (111ab) at its lower portion is configured to have a circular raised projected area with a grill cover (not shown) and a plurality of boss portions (111aba) disposed around its outer periphery. The circular raised projected area (not shown) has a space formed on its inner periphery so as to accommodate the cooling fan (301) completely enclosing it. The plurality of boss portions (111aba) which are distributed equidistant to each other match exactly with the corresponding boss portions (111aab) on the inner fan shroud (111aa). Hence, the outer fan shroud (111ab) and inner fan shroud (111aa) abut perfectly and can be attached using attaching means such as fasteners (305b). When covered, the space between the outer fan shroud (111ab) and the inner fan shroud (111aa) provide an air path to guide the atmospheric air towards the cylinder block (303) and the cylinder head (302). The gentle curved shape of the air path ensures smooth and turbulent free air flow towards the upper portions of the cylinder unit (302, 303) and directs the air flow without any loss in velocity; the air path ensures air recirculation and prevents air stagnation. A grill cover (not shown) provides a passage to draw the atmospheric air inside when the cooling fan (301) is in operation. The grill cover (not shown) also acts as a protective cover, preventing atmospheric contaminants such as water, mud, stones and other particles from entering the interior portions of the forced cooling system and cause damage to the components within it.
[00041] In one embodiment, the cooling fan (301) is designed to be of centrifugal type and comprises a central hub (not shown), plurality of twisted vanes (301a) and a back-plate (301b) on which the central hub (not shown) and plurality of twisted guide vanes (301a) are attached. The central hub (not shown) has plurality of holes disposed on its rear end which is used to mount the cooling fan (301) on the outer rotor of the magneto assembly or ISG (306) by using fastening means like fasteners (305c). The back-plate (301b) also forms part of the rear end of the cooling fan (301) to which the central hub (not shown) is attached. The plurality of twisted guide vanes (301a) is disposed radially and equidistant around the outer portion of the back-plate (301b). The guide vanes (301a) are twisted such that, atmospheric air is drawn in due to pressure difference near the central hub (not shown) and due to centrifugal force the air is pushed towards the outer parts of the cooling fan (301) which is received by the twisted guide vanes (301a). The guide vanes (301a) then direct the air towards the cylinder unit shroud part (111b) by joining the air path.
[00042] Figure 4a illustrates a top cut section view of the engine assembly (102) across A-A’ axis and a localized side view of engine assembly (102) where few parts are omitted from the figure. Figure 4b illustrates an enlarged localized exploded view of the engine assembly. Figure 4a and 4b will be discussed together for brevity. The detection means grommet (308) is positioned in a detection means grommet slot (401) provided in the RH Crankcase (206a). A portion of the detection means grommet (308) is in contact with a portion of the piece cowl (309). The piece cowl (309) and detection means (307) are detachably attached to the RH Crankcase (206a) using fastening means like fasteners (402). As per an embodiment, a pair of threaded fasteners (402) fastens both detection means (307) and piece cowl (309) such that the piece cowl (309) overlaps a portion of the detection means (307) when viewed from the top. As per one implementation, the detection means (307) includes pulsar coil.
[00043] Figure 5 illustrates the piece cowl (309). The piece cowl (309) is configured with a predetermined shape in order to mate with the inner fan shroud (111aa) (as shown in figure 3) and the RH crankcase (206a) (as shown in figure 3) in a stable & rigid manner. The piece cowl (309) has a bend (B) at a predetermined angle. The bend angle is an obtuse angle forming a substantially L –shape piece cowl (309). The piece cowl (309) comprises a base member (309a) of predetermined thickness. More specifically, the thickness of base member (309a) is less than the thickness of outer peripheral wall of the RH crankcase (206a) (as shown in figure 3). The base member (309a) has a side surface (309aa), a top surface (309ab) and a bottom surface (309ac). The bottom surface (309ac) is configured to have a pair of attachment portion (309aca). The attachment portion (309aca) includes at least one opening (309acaa) adapted to receive the fasteners (402) (as shown in figure 4).The attachment portion (309aca) are provided with ribs (309acab). The ribs (309acab) add more stiffness to the piece cowl (309). A front end of the base member (309a) is configured to have a hugging profile (309ad) which is formed to connect with the RH crankcase (206a) (as shown in figure 3). Further, a rear end of said piece cowl (309) includes an inclined portion (309ae). The inclined portion (309ae) is extending in lateral direction (X-X’) of the vehicle (100) (see figure 4). Specifically, towards the inner fan shroud (111aa). Further, the inclined portion (309ae) bends downwardly in the longitudinal direction (Y-Y’) of the vehicle (100) (see figure 4). The side surface (309aa) includes a stepped portion (309aaa) profiled to butt with a portion of said RH crankcase (206a) (as shown in figure 3). Furthermore, the top surface(309ab) is configured to have a semicircular projection (309aba) adapted to butt with a portion of RH crankcase (206a) (as shown in figure 3).
[00044] According to above architecture, the primary efficacy of the present invention is that the due to above architecture the piece cowl is configured to eliminate the gap between the detection means slot and the inner fan shroud which secure dimensional stability of the grommet.
[00045] According to above architecture, the primary efficacy of the present invention is that the one or more piece cowl improves air circulation through forced air circulation system due to elimination of leakage through any gap arising out of manufacturing constraints.
[00046] According to above architecture, the primary efficacy of the present invention is that, the piece cowl eliminates the need of complex manufacturing controls for forced air-cooling system.
[00047] According to above architecture, the primary efficacy of the present invention is that the piece cowl has simple design which does not require additional mounting provisions but uses existing mounting provision available for mounting the detection means in the crankcase in a stable & rigid manner.
[00048] While the present invention has been shown and described with reference to the foregoing preferred embodiments, 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 references

F- Front
R –Rear
C – C’ – Lateral axis
Y – Y’ – Longitudinal axis
B Bend
101 Vehicle
102 Engine assembly
103 Muffler
104 Engine assembly
105 Swing arm
106 Rear wheel
107 Rear suspension
108 Air filter assembly
109 Throttle body
110 Intake pipe
111 Forced air cooling system
111a Air introduction part
111aa Inner fan shroud
111ab Outer fan shroud
201 Starter motor
202 Idler gear
203 Ring gear
204 Crankshaft
205 Idler pin
206 Crankcase
207 Idler pin bracket
208 Dowel pins
209 Cover crankcase
210a, 210b Mounting points
211 Extended leg
212 One way clutch
301 Cooling fan
302 Cylinder head
303 Cylinder block
304a, 304b Rubber grommets
305a, 305b, 305c Fasteners
306 Magneto assembly/ISG
307 Detection means
308 Detection means grommet
309 Piece cowl
401 Detection means grommet slot
402 Fasteners
309a Base member
309aa Side surface
309aaa Stepped portion
309ab Top surface
309aba Semi circular projection
309ac Bottom surface
309aca Attachment portion
309acaa Opening in attachment portion
309acab Ribs
309ad Hugging profile
309ae Inclined portion