[001] The present invention relates to an engine unit and, more particularly to, the engine unit for a two-wheeled vehicle.
BACKGROUND

[002] Generally, main components of a power unit of a vehicle such as a two-wheeled vehicle include an engine unit and a transmission unit. Transmission unit of a V-belt type continuously variable transmission (CVT) accommodates a transmission belt, a drive pulley, a driven pulley and other components. Cooling of the transmission unit is important and it is typically performed by taking air from the atmosphere. For example, air enters from the drive pulley side and exits from the driven pulley side thereby cooling the transmission unit.
[003] However, many a times, cooling of the transmission unit may not be adequate due to many factors such as when the transmission unit or the components accommodated therein are modified, or the engine runs continuously for an extended period of time.
SUMMARY
[004] In an embodiment, an engine unit of a two-wheeled vehicle is disclosed. The engine unit includes a power unit, a transmission unit and an air intake duct. The power unit includes a crankshaft and a first air cooling fan. The first air cooling fan is driven by the crankshaft. The first air cooling fan is adapted to suck air from atmosphere and supply the air into the power unit. The transmission unit includes a drive pulley and a driven pulley. The drive pulley is operatively coupled to the crankshaft and the driven pulley. The air intake duct includes a first end portion and a second end portion. The first end portion is connected to the power unit and the second end portion is connected to the transmission unit for supplying a part of air sucked by the first air cooling fan into the transmission unit.
[005] In an embodiment, the air intake duct is tubular. In an embodiment, an air filter is mounted inside the air intake duct. The air filter is configured to supply clean air to the transmission unit.
[006] In an embodiment, the air intake duct is a metallic duct. In another embodiment, the air intake duct is made of at least one of resin and plastic. In an embodiment, the air intake duct is covered by a heat insulation material on outer surface of the air intake duct.
[007] In an embodiment, the transmission unit further includes a second air cooling fan is positioned on an outer surface of the drive pulley. In an embodiment, a cylinder block is attached to a front end of a crankcase, a cylinder head is attached to the cylinder block, and a head cover for covering a front opening in the cylinder head.
[008] In an embodiment, a two-wheeled vehicle is disclosed. The two-wheeled vehicle includes an engine unit including a power unit, a transmission unit and an air intake duct. The power unit includes a crankshaft and a first air cooling fan. The first air cooling fan is driven by the crankshaft and is adapted to suck air from atmosphere and supply the air into the power unit. The transmission unit includes a drive pulley and a driven pulley. The drive pulley is operatively coupled to the crankshaft and the driven pulley. The air intake duct includes a first end portion and a second end portion. The first end portion is connected to the power unit and the second end portion is connected to the transmission unit for supplying a part of air sucked by the first air cooling fan into the transmission unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[009] The invention itself, together with further features and attended advantages, will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings. One or more embodiments of the present invention are now described, by way of example/s only, with reference to the accompanied drawings wherein like reference numerals represent like elements and in which:
[0010] Figure 1 illustrates a schematic side view of a two-wheeled vehicle in accordance with the present invention;
[0011] Figure 2 illustrates a view of an engine unit of the two-wheeled vehicle, according to one embodiment of the present invention;
[0012] Figure 3 illustrates another view of the engine unit, according to one embodiment of the present invention;
[0013] Figure 4 illustrates view of a power unit, according to one embodiment of the present invention;
[0014] Figure 5 illustrates sectional view along the line XX’ as illustrated in Figure 2, according to one embodiment of the present invention; and
[0015] Figure 6 illustrates sectional view along the line YY’ as illustrated in Figure 2, according to one embodiment of the present invention.
[0016] The drawings referred to in this description are not to be understood as being drawn to scale except if specifically noted, and such drawings are only exemplary in nature.
DETAILED DESCRIPTION

[0017] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the invention.
[0018] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
[0019] For the better understanding of this invention, reference will now be made to the embodiments illustrated in greater depth in the accompanying figures and the description given below, further, in the following figures, the same reference numerals are used to identify the same components in various views.
[0020] While the present invention is illustrated in the context of a saddle riding type two-wheeled vehicle, however, the engine unit and other aspects and features thereof can be used with other type of vehicles as well. The terms “vehicle”, “two-wheeled vehicle” and “motorcycle” have been interchangeably used throughout the description. The term “two-wheeled vehicle” includes vehicles such as motorcycles, scooters, bicycles, mopeds, scooter type vehicle, all terrain vehicles (ATV) and the like.
[0021] The terms “front / forward”, “rear / rearward / back / backward”, “up / upper / upward”, “down / downward / lower / lowerward” that may be used therein represent the directions as seen from a vehicle driver sitting astride and these directions are referred by arrows Fr, Rr, U, Lr in the drawing. Further, “left / leftward”, “right / rightward” that may be used herein represent the directions as seen from a vehicle driver sitting astride.
[0022] Figure 1 illustrates side view of a two-wheeled vehicle (100) according to an embodiment of the present invention. The vehicle (100) comprises, inter-alia, a head tube (110), a main frame (112), a pair of rear seat sub-frame such as a left seat sub-frame (114a) and a right seat sub-frame (not shown), a front fork (121), a front fender (109), a front wheel (108), a steering handle bar (107), a seat (106), an engine unit (126) and a rear wheel (127). It may be noted that the vehicle (100) is shown to include above stated parts, however, those skilled in the art would appreciate that the vehicle includes other parts which may not be relevant for explaining the present invention and hence are not shown and described. The two-wheeled vehicle (100) is assembled in conventional manner and hence the description related thereto is also omitted here.
[0023] The engine unit (126) as illustrated in Figure 2 to Figure 6 is a casing housing a power unit (202), a transmission unit (204), an air inlet duct (208) shown as arrow 'D' taking air from atmosphere, and a reduction unit (210). The power unit (202) and the transmission unit (204) are disposed side by side and the reduction unit (210) is rearward of the transmission unit (204).
[0024] The power unit (202) is a single-cylinder, four-stroke-cycle and forced-air-cooling power unit. The power unit (202) comprises a crankcase, a cylinder block (216) attached to the front end of the crankcase, a cylinder head (214) attached to the cylinder block (216), and a head cover (212) for covering a front opening in the cylinder head (214). The power unit (202) is disposed in the vehicle (100) in substantially a horizontal position with the head cover (212) positioned towards the front of the vehicle (100). A crank shaft (238) is supported by the power unit (202) and is connected to a piston. Without limiting to the scope of the present invention, a generator/alternator is provided on the right end of the crank shaft (238). Without limiting to the scope of the present invention, a first air cooling fan (220) (shown in Figure 4) is mounted to right side of the crank shaft (238). A fan cover having plurality of fins, covers the right-side portion of the first air-cooling fan (220). Air is sucked into the power unit (202) by means of the first air cooling fan (220) being driven by the crank shaft (238). For example, the first air-cooling fan (220) is adapted to suck air from the outside and throw the air into the power unit (202) to cool the cylinder block (216) and other components of the power unit (202).
[0025] The transmission unit (204) has a schematic structure constituted by winding a V-belt around a drive pulley (222), which is mounted to a left end of the crankshaft (238), and a driven pulley, which is mounted to a driven shaft. In an embodiment, a second air cooling fan (224) is provided to the outer surface of the drive pulley (222). The second air cooling fan (224) is an integral part of the drive pulley (222) and sucks the air from atmosphere into the transmission unit (204).
[0026] Further, the power unit (202) and the transmission unit (204) are fluidically connected with each other by an air intake duct (206). In an embodiment, the air intake duct (206) is a tubular and metallic duct, and hereinafter referred to as 'tubular air intake duct (206)'. Optionally or additionally, the tubular air intake duct (206) is covered by a heat insulation material from outside. In another embodiment, the tubular air intake duct (206) is made up of at least one of resin and plastic. The tubular air intake duct (206) comprises a first end portion (206a) and a second end portion (206b). The first end portion (206a) of the tubular air intake duct (206) is connected to the power unit (202) at a location near the first air cooling fan (220). The second end portion (206b) is connected to the transmission unit (204) such that a part of the cool air sucked (shown by arrow 'A') by the first air cooling fan (220) is fed (shown by arrow 'B') into the transmission unit (204) through the tubular air intake duct (206) and helps in cooling the CVT. Part of the air sent to the transmission unit (204) is represented by the arrow 'C', and part of air exiting from the transmission unit (204) is represented by the arrow 'E'. In an embodiment, as shown in Figure 5, an air filter (226) is mounted inside the tubular air intake duct (206) so that clean air is sent to the transmission unit (204).
[0027] As described in the aforementioned description, the tubular air intake duct (206) provides an additional cooling provision for the CVT without complicating the CVT structure and which is also very cost effective.
[0028] While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the invention herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

CLAIMS:
We claim:
1. An engine unit (126) comprising:
a power unit (202) comprising a crankshaft (238) and a first air cooling fan (220), the first air cooling fan (220) driven by the crankshaft (238) and adapted to suck air from atmosphere and supply air into the power unit (202);
a transmission unit (204) comprising a drive pulley (222) operatively coupled to the crankshaft (238) and a driven pulley; and
an air intake duct (206) comprising a first end portion (206a) and a second end portion (206b), the first end portion (206a) connected to the power unit (202) and the second end portion (206b) connected to the transmission unit (204) for supplying a part of air sucked by the first air cooling fan (220) into the transmission unit (204).
2. The engine unit (126) as claimed in claim 1, wherein the air intake duct (206) is tubular.
3. The engine unit (126) as claimed in claim 1, further comprising an air filter (226) mounted inside the air intake duct (206), the air filter (226) configured to supply clean air to the transmission unit (204).
4. The engine unit (126) as claimed in any of claims 1 to 3, the air intake duct (206) is a metallic duct.
5. The engine unit (126) as claimed in any of the claims 1 to 3, wherein the air intake duct (206) is made of at least one of resin and plastic.
6. The engine unit (126) as claimed in claim 1, wherein the air intake duct (206) is covered by a heat insulation material on outer surface of the air intake duct (206).
7. The engine unit (126) as claimed in claim 1, wherein the transmission unit (204) further comprises a second air cooling fan (224) positioned on an outer surface of the drive pulley (222).
8. The engine unit (126) as claimed in claim 1, wherein the power unit (202) further comprises a crankcase, a cylinder block (216) attached to a front end of the crankcase, a cylinder head (214) attached to the cylinder block (216), and a head cover (212) for covering a front opening in the cylinder head (214).
9. A two-wheeled vehicle (100) comprising:
An engine unit (126):
a power unit (202) comprising a crankshaft (238) and a first air cooling fan (220), the first air cooling fan (220) driven by the crankshaft (238) and adapted to suck air from atmosphere and supply air into the power unit (202c);
a transmission unit (204) comprising a drive pulley (222) operatively coupled to the crankshaft (238) and a driven pulley; and
an air intake duct (206) comprising a first end portion (206a) and a second end portion (206b), the first end portion (206a) connected to the power unit (202) and the second end portion (206b) connected to the transmission unit (204) for supplying a part of air sucked by the first air cooling fan (220) into the transmission unit (204).
10. The two-wheeled vehicle (100) as claimed in claim 9, further comprising an air filter (226) mounted inside the air intake duct (206), the air filter (226) configured to supply clean air to the transmission unit (204).