Claims: WE CLAIM:
1. An internal combustion engine (100) for a two-wheeled vehicle (200), the engine (100) comprising:
a crankcase (102);
a breather chamber (104) defined on the crankcase (102), the breather chamber (104) adapted to separate oil particles in blow-by gases received from the crankcase (102) and route fresh air to an intake manifold of the engine (100);
a breather cover (106) mounted onto the crankcase (102) and adapted to cover the breather chamber (104); and
an Integrated Starter Generator (ISG) unit (108) having a stator (108a) and a rotor (108b), wherein the rotor (108b) is coupled to a crankshaft (110) disposed within the crankcase (102) and the stator (108a) is mounted on the breather cover (106).

2. The engine (100) as claimed in claim 1, wherein the breather cover (106) comprises one or more vent holes (112) for discharging blow-by gases from the crankcase (102).

3. The engine (100) as claimed in claim 1, wherein the breather chamber (106) is defined on a right-side of the crankcase (102) along a width direction of the vehicle (200) and is coaxial to the crankshaft (110).

4. The engine (100) as claimed in claim 1, wherein the breather chamber (106) is defined with a plurality of web members (114) on its inner surface, the plurality of web members (114) enable settling of oil droplets carried by blow-by gases.

5. The engine (100) as claimed in claim 4, wherein the oil droplets settled from the blow-by gases are stored within the breather chamber (106).

6. The engine (100) as claimed in claim 1 comprising a radiator fan (116) mounted on the rotor (108b) of the ISG unit (108).

7. The engine (100) as claimed in claim 6 comprising a fan shroud (118) mounted on the breather cover (106) and adapted to cover the radiator fan (116), wherein the fan shroud (118) is adapted to support a radiator assembly (120) in front of the radiator fan (116).

8. The engine (100) as claimed in claim 7, wherein the fan shroud (118) and the radiator assembly (120) are mounted along a width direction of the vehicle (200).

9. The engine (100) as claimed in claim 7, wherein the stator (108a) of the ISG unit (108) is mounted onto the breather cover (106) via the fan shroud (118).

10. The engine (100) as claimed in claim 7, wherein the fan shroud (118) is defined with one or more outlet ports (122) for discharging hot air exiting from the radiator assembly (120).

11. The engine (100) as claimed in claim 1, wherein the vehicle (200) is a scooter-type vehicle.

12. A two-wheeled vehicle (200), comprising:
a frame member (202); and
an internal combustion engine (100) mounted onto the frame member (202), the engine (100) comprising:
a crankcase (102);
a breather chamber (104) defined on the crankcase (102), the breather chamber (104) adapted to separate oil particles in blow-by gases received from the crankcase (102) and route fresh air to an intake manifold of the engine (100);
a breather cover (106) mounted onto the crankcase (102) and adapted to cover the breather chamber (104); and
an Integrated Starter Generator (ISG) unit (108) having a stator (108a) and a rotor (108b), wherein the rotor (108b) is coupled to a crankshaft (110) disposed within the crankcase (102) and the stator (108a) is mounted on the breather cover (106).

13. The vehicle (200) as claimed in claim 12, wherein the breather cover (106) comprises one or more vent holes (112) for discharging blow-by gases from the crankcase (102).

14. The vehicle (200) as claimed in claim 12, wherein the breather chamber (106) is defined on a right-side of the crankcase (102) along a width direction of the vehicle (200) and is coaxial to the crankshaft (110).

15. The vehicle (200) as claimed in claim 12, wherein the breather chamber (106) is defined with a plurality of web members (114) on its inner surface, the plurality of web members (114) enable settling of oil droplets carried by blow-by gases.

16. The vehicle (200) as claimed in claim 15, wherein the oil droplets settled from the blow-by gases are stored within the breather chamber (106).

17. The vehicle (200) as claimed in claim 12 comprising a radiator fan (116) mounted on the rotor (108b) of the ISG unit (108).

18. The vehicle (200) as claimed in claim 17 comprising a fan shroud (118) mounted on the breather cover (106) and adapted to cover the radiator fan (116), wherein the fan shroud (118) is adapted to support a radiator assembly (120) in front of the radiator fan (116).

19. The vehicle (200) as claimed in claim 18, wherein the fan shroud (118) and the radiator assembly (120) are mounted along a width direction of the vehicle (200).

20. The vehicle (200) as claimed in claim 18, wherein the stator (108a) of the ISG unit (108) is mounted onto the breather cover (106) via the fan shroud (118).

21. The vehicle (200) as claimed in claim 18, wherein the fan shroud (118) is defined with one or more outlet ports (122) for discharging hot air exiting from the radiator assembly (120).
, Description:FIELD OF THE INVENTION
[001] The present invention relates to a two-wheeled vehicle and more particularly to an internal combustion engine for the two-wheeled vehicle.

BACKGROUND OF THE INVENTION
[002] Typically, vehicles such as saddle type vehicle, are provided with smaller capacity engines. These smaller capacity engines are commonly provided with an Integrated Stator Generator (ISG) unit. The smaller capacity engines are also air cooled (or naturally aspirated) for dissipating the heat generated within the engine during operation, and to maintain a simple construction of the engine. However, advent of modern technology has paved way for improving combustion and cooling for these smaller capacity engines. One such cooling technique employed for these smaller capacity engines is a liquid cooling system.
[003] A scooter type vehicle having such a liquid-cooled engine, generally has closed side panels, wherein a radiator of the cooling system is mounted along with the ISG on a right side of the vehicle. As such, the engine in the scooter vehicle has the radiator and the ISG mounted on the right side of the vehicle. Also, the radiator and the ISG are required to be placed inside body panels along with ISG for aesthetic purposes.
[004] However, such packaging of the radiator in the engine increases width of the scooter vehicle, which is undesirable. Also, such packaging inherently affects compactness of the engine, as other interfacing parts such as hose routing, exhaust etc., are further mounted onto the engine. Further, in certain vehicles, the radiator is placed away from the engine and requires additional space, further affecting compactness of the engine. Additionally, the ISG (both stator and rotor) is directly mounted to a crankshaft of the engine. This results in directly transferring of heat generated from the ISG to heat the oil being circulated in the engine, consequently leading to overheating of oil circulated within the engine, which is undesirable.
[005] In view of the above, there is a need for an internal combustion engine for a two-wheeled vehicle, which addresses one or more limitations stated above.

SUMMARY OF THE INVENTION
[006] In one aspect, an internal combustion engine for a two-wheeled vehicle is disclosed. The engine has a crankcase and a breather chamber defined on the crankcase. The breather chamber is adapted to separate oil particles in blow-by gases received from the crankcase and route fresh air to an intake manifold of the engine. A breather cover is mounted onto the crankcase and is adapted to cover the breather chamber. An Integrated Starter Generator (ISG) unit having a stator and a rotor is also provided. The rotor is coupled to a crankshaft disposed within the crankcase and the stator is mounted on the breather cover.
[007] In an embodiment, the breather cover has one or more vent holes for discharging blow-by gases from the crankcase.
[008] In an embodiment, the breather chamber is defined on a right-side of the crankcase along a width direction of the vehicle and is coaxial to the crankshaft.
[009] In an embodiment, the breather chamber is defined with a plurality of web members on its inner surface. The plurality of web members enable settling of oil droplets carried by blow-by gases. The oil droplets settled from the blow-by gases are stored within the breather chamber.
[010] In an embodiment, a radiator fan is mounted on the rotor of the ISG unit.
[011] In an embodiment, a fan shroud is mounted on the breather cover and adapted to cover the radiator fan. The fan shroud is adapted to support a radiator assembly in front of the radiator fan. The fan shroud and the radiator assembly are mounted along a width direction of the vehicle.
[012] In an embodiment, the stator of the ISG unit is mounted onto the breather cover via the fan shroud.
[013] In an embodiment, the fan shroud is defined with one or more outlet ports for discharging hot air exiting from the radiator assembly.
[014] In an embodiment, the vehicle is a scooter-type vehicle.
[015] In another aspect, the two-wheeled vehicle is provided. The vehicle includes a frame member and the internal combustion engine mounted onto the frame member. The engine includes the crankcase and the breather chamber defined on the crankcase. The breather chamber is adapted to separate oil particles in blow-by gases received from the crankcase and route fresh air to the intake manifold of the engine. The breather cover is mounted onto the crankcase and is adapted to cover the breather chamber. The Integrated Starter Generator (ISG) unit having the stator and the rotor is also provided. The rotor is coupled to a crankshaft disposed within the crankcase and the stator is mounted on the breather cover.

BRIEF DESCRIPTION OF THE DRAWINGS
[016] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 is a schematic view of a vehicle, in accordance with an embodiment of the present invention.
Figure 2 is a perspective view of an internal combustion engine mounted on a frame member of the vehicle, in accordance with an embodiment of the present invention.
Figure 3 is a right-side view of the internal combustion engine mounted on the frame member, in accordance with an embodiment of the present disclosure.
Figure 4 is an exploded view of the internal combustion engine, in accordance with an embodiment of the present disclosure.
Figure 5 is an exploded view of the internal combustion engine, in accordance with an embodiment of the present disclosure.
Figure 6 is a sectional view of the internal combustion engine, in accordance with an embodiment of the present disclosure.
Figure 7 is a perspective view of a crankcase of the internal combustion engine depicting a breather chamber, in accordance with an embodiment of the present disclosure.
Figure 8 is a perspective view of the breather cover, in accordance with an embodiment of the present disclosure.
Figure 9a is a perspective view of a fan shroud, in accordance with an embodiment of the present disclosure.
Figure 9b is a side view of the fan shroud, in accordance with an embodiment of the present disclosure.
Figure 9c is a front view of the fan shroud, in accordance with an embodiment of the present disclosure.
Figure 9d is a front view of the fan shroud, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION
[017] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out hereunder.
[018] Figure 1 illustrates a schematic view of a vehicle 200, in accordance with an embodiment of the present invention. As an example, the vehicle 200 is a scooter type vehicle. The vehicle 200 has a transmission system (not shown) including an internal combustion engine 100 (for e.g. as shown in Figures 2 and 3) as a prime mover, that is disposed behind a floorboard 204 and below a seat assembly 206 and/or a storage bin (not shown). In an embodiment, the transmission system includes a combination of an electric motor (not shown) and the internal combustion engine 100 as the prime mover as per design feasibility and requirement. The vehicle 200 has a front wheel 208, a rear wheel 222 and a frame member 202 (for e.g. as shown in Figures 2 and 3).
[019] A head pipe (not shown) connects to the frame member 202. The head pipe supports a steering shaft (not shown) and a front suspension 212 attached to the steering shaft through a lower bracket (not shown). The front suspension 212 supports the front wheel 208. The upper portion of the front wheel 208 is covered by a front fender 214 mounted to the front suspension 212. In an embodiment, the front fender 214 is movable along with the front wheel 208, during travel over undulations on a road surface. A handlebar 216 is fixed to upper bracket (not shown) and can rotate about the steering shaft for turning the vehicle 200. A headlight 218 and an instrument cluster 220 are arranged on an upper portion of the head pipe.
[020] Further, a rear suspension (not shown) is provided to the rear wheel 222 for dampening the vibrations at a rear end of the vehicle 200, induced during travel of the vehicle 200 over undulations on the road surface. A taillight unit 224 is disposed at the end of the vehicle 200 and at the rear of the seat assembly 206. A grab rail 226 is also provided for facilitating the grip and/or balance to a rider/pillion on the vehicle 200 during movement. The rear wheel 222 is arranged below the seat assembly 206 and is adapted to receive the motive force from the prime mover. A suitable transmission assembly is provided for transferring the drive force from the prime mover onto the rear wheel 222 for driving the vehicle 200. In an embodiment, the driving force of the internal combustion engine 100 is transmitted through a chain drive (not shown) or a belt drive (not shown). A rear fender 228 is disposed above the rear wheel 222. An exhaust pipe (not shown) is also provided for the internal combustion engine 100, that extends therefrom towards the rear end of the vehicle 200.
[021] Referring to Figures 2 and 3 in conjunction with Figure 1, the internal combustion engine 100 (hereinafter referred to as ‘engine 100’) mounted onto the frame member 202 is depicted. In the present embodiment, the engine 100 is oriented horizontally. In another embodiment, the engine 100 is oriented vertically or inclined with respect to a longitudinal axis of the vehicle 200. The engine 100 includes a cylinder block 230 having a piston (not shown) and a piston rod (not shown), adapted to generate the motive force required for movement of the vehicle 200. A cylinder head 232 is mounted on the cylinder block 230 and is adapted to provide required quantity of fuel and/or fuel and air mixture to the engine 100 for combustion. The cylinder head 232 includes an intake manifold (not shown) which provides required quantity of fuel and/or fuel and air mixture to the engine 100 for combustion. The intake manifold is connected to an air cleaner (not shown) for receiving filtered air.
[022] Further, the engine 100 includes a crankcase 102 defined below the cylinder block 230. The crankcase 102 houses a crankshaft 110 (for e.g. as shown in Figure 5) coupled to the piston rod for providing the motive force received from the cylinder block 230 to the rear wheel 222. In an embodiment, the crankshaft 110 is configured to transform the reciprocating movement of the piston rod to a rotational movement, and then provide the rotational movement to the rear wheel 222 for movement of the vehicle 200. The crankcase 102 also stores oil required for lubricating the engine 100. The oil stored within the crankcase 102 is circulated by the piston into the cylinder block 230 for lubrication during operation. In an embodiment, the piston circulates the oil in the crankcase 102 to the cylinder block 230 during its movement from a bottom dead centre position (not shown) to a top dead centre position (not shown).
[023] Referring to Figures 4-8 in conjunction with Figures 2 and 3, the crankcase 102 is defined with a breather chamber 104. In other words, the breather chamber 104 is integrated within the crankcase 102. Alternatively, the breather chamber 104 may be attached onto the crankcase 102, without departing from the scope of the present disclosure. The breather chamber 104 is defined such that, blow-by gases generated in the crankcase 102 flows into the breather chamber 104. The breather chamber 104 is adapted to separate oil particles in blow-by gases received from the crankcase 102 and route fresh air to the intake manifold of the engine 100 (the fresh air routing is depicted via arrows in Figure 7). In the present embodiment, the breather chamber 104 is positioned on a right-side of the crankcase 102. In an embodiment, the breather chamber 104 is positioned on the crankcase 102 as per design feasibility and requirement. Further, the dimensions or construction of the breather chamber 104 is selected to enable separation of oil from blow-by gases efficiently. In an embodiment, the blow-by gases may be accumulated gases or oil mist that is leaked into the crankcase 102, typically from the cylinder block 230 during operation of the engine 100.
[024] In an embodiment, the breather chamber 104 is provided with a slot 104b (for e.g. as shown in Figure 7) defined at its central portion. The slot 104b facilitates extension of the crankshaft 110 from the crankcase 102. Consequently, ensuring coaxial mounting of the breather chamber 104 with the crankshaft 110 (for e.g. as shown in Figure 6). Accordingly, dimensions of the slot 104b is provided corresponding to the dimensions of the crankshaft 110. Such a construction ensures compactness of the engine 100, even after providing the breather chamber 104 on the crankcase 102. In an embodiment, the slot 104b can be provided at any location or position on the breather chamber 104, as per design feasibility and requirement of the engine 100 and/or the vehicle 200.
[025] In the present embodiment, the breather chamber 104 is provided with a plurality of web members 114 on its inner surface for separating the oil particles in the blow-by gases. The plurality of web members 114 extend from an outer periphery 104a (for e.g. as shown in Figure 7) towards a central portion of the breather chamber 104. The blow-by gases received from the crankcase 102 flow on surface of the plurality of web members 114, resulting in separation of the oil from the blow-by gases due to difference in their densities (i.e. of the gas and the oil). As such, the construction or configuration of the plurality of web members 114 is defined to enable separation of oil from the blow-by gases during flow. In an embodiment, the plurality of web members 114 form an arbitrary pattern within the breather chamber 104, wherein the arbitrary patterns allow flow of blow-by gases on its surface for ensuing oil separation due to density difference. The flow of the blow-by gases is indicated via arrow markings in Figure 7. The oil separated from the blow-by gases is settled within the breather chamber 104. The settled oil is stored within the breather chamber 104. Thus, the breather chamber 104 acts as an oil drain sump for the engine 100.
[026] Further, a breather cover 106 (for e.g. as shown in Figure 8) is mounted onto the crankcase 102 and adapted to cover the breather chamber 104. The breather cover 106 is provided with plurality of vent holes 112 defined along its peripheral surface for venting out hot gases, typically leaked into the crankcase 102. In an embodiment, the construction and configuration of each of the plurality of vent holes 112 is selected as per feasibility and requirement. In an embodiment, the dimensions and configuration of the breather cover 106 corresponds to the dimensions and configuration of the breather chamber 104, so that the breather cover 106 covers the breather chamber 104. Additionally, the breather cover 106 is also defined with a slot 124 along the axis of the breather chamber 104, for facilitating extension of crankshaft 110 from the breather chamber 104. Such a construction ensures coaxial mounting of the breather cover 106 onto the breather chamber 104 (for e.g. as shown in Figures 4-6), consequently ensuring compactness of the engine 100.
[027] In an embodiment, the breather cover 106 is defined with a stepped profile 106a, 106b, wherein dimensions of the profile 106b is larger than the profile 106a. The profile 106b is adapted to engage with the crankcase 102, while the profile 106a conforms to the dimensions of the breather chamber 104. In the present embodiment, the breather cover 106 is provided with mounting provisions 126 for fastening onto the crankcase 102. The mounting provisions 126 are mounting holes positioned selectively thereon, which are configured to receive a fastener (not shown) for fastening the breather cover 106 onto the crankcase 102. In an embodiment, the mounting provisions 126 are provided for the profile 106a and/or profile 106b of the breather cover 106.
[028] In another embodiment, the breather cover 106 includes one or more ribs 128 defined on its inner surface. The ribs 128 are positioned corresponding to position of the web members 114, so that the ribs 128 engage with the web members 114 for ensuring settling and storing of the oil separated from the blow-by gases with the breather chamber 104. Thus, the ribs 128 complement the web members 114, thereby ensuring oil storage within the breather chamber 104.
[029] In an embodiment, the breather chamber 104 and the breather chamber 106 are made of a metallic material or a composite material as per design feasibility and requirement. In another embodiment, the breather cover 106 is also mounted on the right-side of the crankcase 102. In an embodiment, the breather cover 106 is also adapted to receive and support a pulsar coil (not shown).
[030] Further, an Integrated Starter Generator (ISG) unit 108 having a stator 108a and a rotor 108b is provided in the engine 100. The ISG unit 108 is mounted to the crankcase 102 of the engine 100 such that, the rotor 108b is coupled to the crankshaft 110 and the stator 108a is mounted on the breather cover 106. Such a construction or mounting, ensures that the ISG unit 108 is mounted on the breather cover 106 instead of mounting on the crankcase 102 directly. Thus, eliminating direct transfer of heat generated in the ISG unit 108 to the oil stored within the crankcase 102, thereby ensuring optimum operating temperature of the oil as well as the engine 100. Additionally, due to mounting of the rotor 108b onto the crankshaft 110, the requirement of additional coupling parts is eliminated, thereby reducing the number of parts in the engine 100. Consequently, effort required during assembly as well as service is reduced. In an embodiment, the dimensions and configuration of the ISG unit 108 is selected as per design feasibility and requirement.
[031] Further, a fan shroud 118 (for e.g. as shown in Figures 9a-9d) is mounted on the breather cover 106. The fan shroud 118 is adapted to cover a radiator fan 116 coupled to the rotor 108b of the ISG unit 108 and support a radiator assembly 120 in front of the radiator fan 116. Such a construction of the radiator fan 116 and the radiator assembly 120 ensures that, fresh air is routed through the radiator assembly 120 upon operation of the radiator fan 116. Consequently, enabling cooled fresh air to enter the intake manifold via the breather chamber 104, while retaining compactness of the engine 100. Also, due to direct mounting of the radiator fan 116 on the rotor 108b, additional components required for coupling are mitigated, thereby reducing components in the engine 100.
[032] In an embodiment, the dimensions and configuration of the radiator fan 116 are selected as per design feasibility and requirement. In an embodiment, the breather chamber 104 is defined with an outlet port 136 (for e.g. as shown in Figure 7) for routing the separated blow-by gases or cooled fresh air into the intake manifold of the engine 100. In an embodiment, the outlet port 136 routes the separated blow-by gases or cooled fresh air into the intake manifold via an air cleaner (not shown).
[033] In the present embodiment, the fan shroud 118 includes a frame surface 118a (as shown in Figures 9a-9d) adapted to support the radiator assembly 120. From the frame surface 118a, an annular portion 118b projects and is adapted to cover the radiator fan 116. In an embodiment, the annular portion 118b extends towards the crankcase 102. In an embodiment, the annular portion 118b projects from a rear portion of the frame surface 118a. Further, a front portion of the frame surface 118a is adapted to support the radiator assembly 120.
[034] At a central portion of the annular portion 118b, an opening 130 is defined for enabling mounting of the radiator fan 116 with the rotor 108b. Accordingly, the dimensions of the opening 130 are selected as per dimensions of the radiator fan 116. Additionally, the annular portion 118b extending from the frame surface 118a is defined with one or more outlet ports 122 for discharging hot air exiting from the radiator assembly 120. Further, the fan shroud 118 is made of a metallic material or a composite material as per design feasibility and requirement. In an embodiment, the fan shroud 118 also acts as a supporting member for the stator 108a, so that the stator 108a is mounted onto the breather cover 106 via the fan shroud 118. In an embodiment, the dimensions and configuration of the outlet ports 122 are considered as per design feasibility and requirement of discharging the hot air.
[035] In an embodiment, the fan shroud 118 and the radiator assembly 120 are mounted along a width direction of the vehicle 200. In an embodiment, the fan shroud 118 is also defined with mounting provisions 132 along the frame surface 118a and/or the annular portion 118b (similar to mounting provisions 126) for enabling mounting of the fan shroud 118 onto the crankcase 102. The mounting provisions 132 are provisions for receiving fasteners so that the radiator assembly 120 is fastened onto the frame surface 118a of the fan shroud 118. Additionally, to the radiator assembly, a radiator cover 134 (as shown in Figure 5) is also provided, for covering the radiator assembly 120. The radiator cover 134 is provided with a mesh surface for providing ingress protection to the radiator assembly 120.
[036] In an embodiment, the radiator fan 116 is coupled to the rotor 108b via conventional coupling techniques known in the art. Similarly, the rotor 108b is mounted to the crankshaft 110 via conventional mounting techniques known in the art.
[037] In an embodiment, the engine 100 is started by a separate starter motor (not shown) or the ISG unit 108, which can also be used for charging a battery (not shown) of the vehicle 200. In another embodiment, for reducing the emissions generated and to increase the temperature of the engine 100 during low temperature conditions, the ISG unit 108 or the starter motor is employed for a few cycles without ignition and fueling for starting the engine 100. Consequently, resulting in scavenging of cold gases inside the engine 100 and heating of the engine 100 is achieved via compression of air for few cycles. In an embodiment, operation of the starter motor or the ISG unit 108 for starting the engine 100 can be optimized via decompression system (not shown) tuning techniques and/or by selecting suitable engine operating conditions. Additionally, the engine 100 with the decompression system routes a significant amount of charge back to the intake manifold which is at higher temperature, resulting in enhancing temperature of charge at a faster rate.
[038] In an embodiment, a thermostat (not shown) is mounted on the cylinder head 232 in a coolant outlet (not shown). The thermostat is adapted to improve cooling efficiency in the engine 100 by regulating the flow of coolant returning to the radiator assembly 120 by allowing the coolant after reaching a pre-determined temperature and thus help in maintaining the optimum temperature in the engine 100. In an embodiment, a hollow-boss thermostat is fixed to the cylinder head 232.
[039] In an embodiment, a bypass hose (not shown) is provided which connects the cylinder head 232 as well as a coolant pump (not shown), for bypassing a coolant (not shown) from the radiator assembly 120. Without the bypass hose, during cold conditions of the engine 100, the thermostat does not open since temperature of the coolant doesn’t reach the required temperature (for e.g. 82°C), thereby preventing coolant from circulating. Such a scenario leads to pump overload. By providing the bypass hose, thermostat opening is improved, thereby enhancing cold startability characteristics of the engine 100. The bypass hose skips the radiator assembly 120 and re-circulates the coolant till the thermostat opens, thereby enhancing cold startability of the engine 100.
[040] In an embodiment, the radiator assembly 120 is fluidically coupled to a coolant reservoir 138 (as shown in Figure 2). The coolant reservoir 138 is adapted to circulate coolant within the radiator assembly 120, so that the fresh air drawn by the radiator fan 116 is cooled. In an embodiment, the coolant circulated by the coolant reservoir 138 is selected from one of a water, glycol, or any other coolant as per design feasibility and requirement.
[041] Advantageously, the present disclosure provides the engine 100 which is defined with a compact layout, due to the mounting arrangement of the ISG unit 108 onto the breather chamber 104. The engine 100 is also configured with reduced number of components, thereby improving serviceability, and reducing effort for assembly. Further, the engine 100 is provided with the breather chamber 104, which facilitates ventilation of the crankcase 102 and acts as an oil drain sump for the oil separated from blow-by gases. Additionally, due to mounting of the ISG unit 108 on the breather cover 106 instead of mounting on the crankcase 102, direct transfer of heat generated in the ISG unit 108 to the oil stored within the crankcase 102 is eliminated, thereby ensuring optimum operating temperature of the oil as well as the engine 100. Further, due to mounting of the rotor 108b onto the crankshaft 110 directly, the requirement of additional coupling parts is eliminated, thereby reducing the number of parts in the engine 100. Consequently, reducing effort required during assembly as well as service. In an embodiment, the dimensions and configuration of the ISG unit 108 is selected as per design feasibility and requirement. Furthermore, engine 100 is made compact, thereby reducing width of the engine 100.
[042] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

List of Reference Numerals
100 - Internal combustion engine
102 - Crankcase
104 - Breather chamber
104a - Outer periphery
104b - Slot
106 - Breather cover
108 - ISG unit
108a - Stator
108b - Rotor
110 - Crankshaft
112 - Vent holes
114 - Web members
116 - Radiator fan
118 - Fan shroud
118a - Frame surface of fan shroud
118b - Annular portion of fan shroud
120 - Radiator assembly
122 - Outlet ports
124 - Slot
126 - Mounting provisions
128 - Ribs
130 - Opening on annular portion
132 - Mounting provisions
134 - Radiator cover
136 - Outlet port
138 - Coolant reservoir
200 - Two-wheeled vehicle
202 - Frame member
204 - Floorboard
206 - Seat assembly
208 - Front wheel
212 - Front suspension
214 - Front fender
216 - Handlebar
218 - Headlight
220 - Instrument cluster
222 - Rear wheel
224 - Taillight unit
226 - Grab rail
228 - Rear fender
230 - Cylinder block
232 - Cylinder head