TECHNICAL FIELD
[0001] The present subject matter relates generally to an internal combustion engine for a two-wheeled vehicle. More particularly, the present subject matter relates to a compact layout of internal combustion engine for two-wheeled vehicle.
BACKGROUND
[0002] A conventional internal combustion engine converts chemical energy into mechanical energy by combustion of air-fuel mixture within a combustion chamber of the engine. The engine, among other components, has a cylinder on top of which a cylinder head is mounted, and receives a reciprocating piston from the bottom. On combustion of the air-fuel mixture, the piston transfers the energy generated during combustion to a crankshaft through a connecting rod thereby driving the crankshaft. In this way, the reciprocatory motion of the piston is converted to rotary motion of the crankshaft. The crankshaft rotation then powers the vehicle.
[0003] Operation of such conventional engines generates vibrations and other internal forces due to reciprocating masses. In order to cancel out such forces, a plurality of counter weights are generally used, such counterweights being arranged within the crankcase. Counter weights balance out the inertial forces of the engine by operating at the same frequency (or a multiple thereof), but phase-shifted through 180 degrees. This means that when the piston moves downwards, the counterweight moves upwards and vice versa. In numerous

arrangements in prior art, counterweights have been provided on both the crankshaft and an altogether different shaft called a balancer shaft. For the arrangement to work in harmony the balancer shaft is located in the crankcase and takes drive from crankshaft and rotates in opposite direction of crankshaft with the same speed.
[0004] In addition, there has been a need to accommodate cooling systems and starter systems including electric and manual i.e., kick starting systems within the internal combustion engine assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.
[0006] Fig. 1 shows a side view of a two-wheeled motorcycle.
[0007] Fig. 2 shows a cross-sectional view of an internal combustion engine of the two-wheeled vehicle.
[0008] Fig. 3 shows a layout 300 of the internal combustion engine in accordance with a first embodiment of the present subject matter.
[0009] Fig. 4 (a) shows an electric starter system 400-1 of the internal combustion engine in accordance with a first embodiment of the present subject matter.

[00010] Fig. 4 (b) shows a side view of the electric starter system 400-1 of the internal combustion engine shown in Fig. 4 (a) in accordance with an embodiment of the present subject matter.
[00011] Fig. 4 (c) shows an internal combustion engine assembly 400-2 in accordance with an embodiment of the present subject matter.
[00012] Fig. 4 (d) shows a balancing system 400-3 of the internal combustion engine in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
[00013] Almost all conventional engines used in two-wheeled vehicles are cranked using a kick-start mechanism, while the rest of the engines are cranked using both kick-start mechanism and electric starter mechanism. There is an ever-increasing demand for compact sized engines having reduced weight and enhanced fuel efficiency.
[00014] Conventionally, internal combustion engine assembly includes a crankcase, a cylinder block coupled to the crankcase, and a cylinder head mounted on the upper part of the cylinder block. A reciprocating piston that is slidably fitted in the cylinder block is connected via a connecting rod to a crankshaft. The crankshaft that is rotatably supported by the crankcase includes a crankshaft inner diameter and a crankshaft web outer diameter on left hand (LH) side and right side (RH) side of the centrally disposed connecting rod. Generally, the LH and RH crankshaft drives a plurality of gears to operate one or more systems of the internal combustion engine. For instance, a conventional electric starter system

includes a starter or ring gear coupled to crankshaft that drives a drive pinion, which in turn drives a bendix drive that is coupled to an electric starter motor. Similarly, conventional cooling system involves an oil pump drive gear coupled to the crankshaft, which operates an oil pump by transmitting rotary motion through an oil pump driven gear. Conventional internal combustion engines, also includes a balancing system having a balancer web that is operated by means of a balancer shaft driven gear, which is coupled to a balancer shaft drive gear, which in turn is rotatably coupled to the crankshaft.
[00015] Generally, presence of one or more of the balancing mechanism and the electric starter mechanism and/or kick starting mechanism, adversely affects engine compactness, increases weight and leads to complexities in design of various subsystems inside the engine. Further, implementation of cooling system in addition to the balancing mechanism within the assembly of the diesel engine involves employment of additional shafts, counterweights, chain-pulley mechanisms etc. Such employment of additional components adds to the number of components, which in turn adds to the weight and size of the components within the engine assembly. As a result, the manufacturing cost and the maintenance cost associated with the engine assembly rise considerably.
[00016] Furthermore, the operation of various gears in tandem with each other causes unwanted noise within a transmission assembly of the IC engine. The production of such noise is attributed to an unwanted characteristic exhibited by the gears. Moreover, the presence of several gears attributing to starting, cooling, and balancing mechanisms makes the internal combustion engine assembly bulky.

Such a bulky nature of the engine causes the layout of the internal combustion engine in the two-wheeled vehicle less compact. Further, the increased number of parts results in increased gross weight of the internal combustion engine assembly. Moreover, the assembly of components pertaining to various systems becomes increasingly complex.
[00017] The present subject matter is aimed at solving the problems posed by the conventional internal combustion engine assembly. The present subject matter provides an internal combustion engine assembly that is compact with reduced number of parts, reduced gross weight, and reduced complexity.
[00018] These and other advantages of the present subject matter would be described in greater detail in conjunction with the figures in the following description.
[00019] Fig. 1 illustrates a side view of a two-wheeled vehicle, for example, a motorcycle 1 according to an embodiment. The motorcycle 1 according to an embodiment includes a front wheel 101 steered by a handlebar 102 and a rear . wheel 103 supported by a swing arm 104. Steering system parts including the handlebar 102 and the front wheel 101 are supported for pivotal steering operation on a head pipe 105 at the front end of the vehicle body frame 106. A seat 110 for a driver and a pillion is placed rearward to a fuel tank 114. An engine assembly 113 is disposed below the fuel tank. A front fender 111 is provided above the front wheel 101 to avoid the said vehicle and its occupants from being splashed with mud. Likewise, a rear fender 112 is placed above the rear wheel 103, and to the

outer side in the radial direction of rear wheel 103. Rear fender 112 inhibits rainwater or the like from being thrown up by rear wheel 103.
[00020] The swing arm 104 along with a shock absorber 109 is supported at a front portion thereof for pivotal motion and upward and downward rocking motion on the rear side of a lower portion of the vehicle body frame 106. A suspension system including a pair of front forks 108 and the shock absorber 109 is provided in the two-wheeled vehicle 1 for providing better ride comfort to the rider. In general terms, the shock absorbers help cushion vehicles on uneven roads. In the two-wheeled vehicle, shock absorbers reduce the effect of traveling over rough ground, leading to improved ride quality and vehicle handling.
[00021] The vehicle body frame 106 includes the head pipe 105, a pair of left and right main frames 107. The head pipe 105 is positioned at a front-end portion of the vehicle body frame 106. The main frames 107 extend in a leftwardly and rightwardly branching state obliquely downwardly rearwardly from a lower portion of the head pipe 105.
[00022] Fig. 2 shows a cross-sectional view of an internal combustion engine 113 of the two-wheeled vehicle 100. In an embodiment, rotation of a connecting rod 212 connects a piston (not shown in Fig 2) of the IC engine 113 with a crankshaft through a bearing (not shown in Fig 2). A primary drive gear 214 is operably connected to the crankshaft and rotates with the speed of rotation of the crankshaft. The connecting rod 212 transfers the motion of the piston to the crankshaft by way of conversion of the reciprocating motion of the piston into rotary motion of the crankshaft. The primary drive gear 214 acts as a motion

transmitting means to facilitate transmission of the rotary motion of the crankshaft to a drive-train system (not shown in Fig 2) and to various other components of the IC engine 113 through a primary driven gear 216. Further, in one embodiment, a balancer drive gear 222 meshes with the primary drive gear 214, which in turn transmits motion to a balancer driven gear 218. In an embodiment, the balancer drive gear 222 is rotated at the speed of rotation of the crankshaft. Further, in one embodiment, the primary drive gear 214 meshes with an oil pump drive gear 224 that enables operation of oil pump by transfer of motion through oil pump driven gear (not shown in Fig.2).
[00023] Fig. 3 shows a layout 300 of the internal combustion engine in accordance with a first embodiment of the present subject matter. In ian embodiment, the layout 300 of the internal combustion engine 113 of the present subject matter includes elimination of one or more components, for example, a starter gear or a ring gear, which is integrated to at least one crankshaft web OD 206 of the engine 113. A functional system 201, which is starter system 201, which works in conjunction with said internal combustion engine assembly, is provided. The starter system includes a starter motor 202 coupled to a bendix drive 304 and a pinion driven gear 410 of the bendix drive (304). In an embodiment, the integration of the ring gear to at least one crankshaft web OD 206 eliminates the need for a separate starter gear or a ring gear that enables . transmission of motion from the primary gear 214 to an electric starter motor 202. Further, in one embodiment, the integration of the ring gear on to at least one crankshaft web OD 206 enables elimination of one or more components involved

in other systems of the IC engine 113, for example, in case of a balancing system, a balancer shaft drive gear (not shown in Fig. 3) is eliminated, as a balancer shaft driven gear 218 is directly coupled to the at least one crankshaft web OD 206 that is integrated with a ring gear. Similarly, in case of an oil cooling system of the IC engine 113, an oil pump drive gear (not shown in Fig. 3) is eliminated, as an oil pump driven gear (not shown) is capable of being directly coupled to the at least one crankshaft web OD 206. Further, in case of a typical electric starter system, an electric starter motor 202 that is driven by means of a bendix drive 304, which is coupled to a drive pinion 302, is directly coupled with the at least one crankshaft web OD 206 instead of being coupled through a separate ring gear (not shown). Hence, the layout 300 of the internal combustion engine 113 of the present subject matter, presents a compact layout that is both less in weight and less complex to be assembled in the space available for the two-wheeled vehicle 100.
[00024] Fig. 4 (a) shows an electric starter system 400-1 of the internal combustion engine 113 in accordance with a first embodiment of the present subject matter. In an embodiment, the electric starter system 400-1 of the present subject matter includes a starter system 201, which is a functional system for cranking the engine 400-1, including an electric starter motor 202 that is coupled to the bendix drive 304. In an embodiment, the bendix drive 304 or any other component functioning similar to the bendix drive 304 acts an intermediate member that transmits motion from a ring gear 402 integrated on the at least one crankshaft web OD 206. The ring gear 402 meshes with a pinion driven gear

410 of the bendix drive 304 ensuring that the bendix drive rotates in the same speed as that of the ring gear 402. The bendix drive 304, in an embodiment, includes a pinion drive gear 302 that meshes or engages directly with the electric starter motor 202 enabling transmission of motion from the ring gear 402 to the electric starter motor 202.
[00025] Fig. 4 (b) shows a side view of the electric starter system 400-1 of the internal combustion engine shown in Fig. 4 (a) in accordance with an embodiment of the present subject matter. A functional system 201 that includes a starter system 201 is provided. In an embodiment, the side view of the electric starter system 400-1 shows the ring gear 402 provided on at least one of the crankshaft
*
web OD 206 meshes or engages directly with the pinion driven gear 410 of the bendix drive 304, while the pinion drive gear 302 (not shown in Fig. 4 (b)) meshes or engages directly with the electric starter motor 202 enabling the ring gear 402 to drive the electric starter motor 202. In an embodiment, the elimination of a separate starter gear for driving the electric starter motor 202 ensures that the . electric starter motor 202 is disposed closer to the crank web OD 206 provided with the ring gear 402. Thus, the layout 300 of the engine 113 becomes much more compact
[00026] Fig. 4 (c) shows an internal combustion engine assembly 400-2 in accordance with an embodiment of the present subject matter. In one embodiment, the internal combustion engine assembly 400-2 of the present subject matter includes the ring gear 402 provided on at least one crankshaft web OD 206. One or more functional systems 201, 301, 401 that includes a starter

system 201, a balancer system 301, and an oil cooling system 401 are provided. The functional systems 201, 301, 401 works in conjunction with said internal combustion engine 400-2. Each functional system 201, 301, 401 of said includes a driven gear 218, 220, 410. Furthermore, the functional system may include a cooling system (not shown) or the like that work in conjunction with the engine 400-2. The ring gear 402, in an embodiment, is coupled to the balancer shaft driven gear 218 enabling rotation of the balancer shaft 404 (not shown in Fig. 4 (c)). In another embodiment, the ring gear 402 of.the present subject matter is directly coupled to the oil pump driven gear 220 thereby eliminating the need for a separate oil pump drive gear (not shown). In yet another embodiment, the ring gear 402 of the present subject matter that is provided on at least one crankshaft web OD 206 meshes or engages directly with the pinion driven gear 410 (not shown) of the bendix drive 304, which in turn drives the pinion drive gear 302 ensuring transfer of motion to the electric starter motor 202, thereby eliminating a separate starter gear. The internal combustion engine assembly 400-2 of the present subject matter is compact as components, for example, driven gears of one or more systems of the internal combustion engine assembly 400-2 are directly coupled to the ring gear 402 provided on at least one crankshaft web OD 206. Thus, the internal combustion engine assembly 400-2 of the two-wheeled vehicle 100 is capable of being disposed in any given vehicle layout with ease. Moreover, the reduction in number of parts causes reduction in gross weight of the engine 113, which in turn helps in achieving improved fuel efficiency and drivability of the two-wheeled vehicle 100. Further, in one embodiment, the integration of the

ring gear 402 on at least one crankshaft web OD 206 ensures oil pump is optimally driven enabling lubrication of the engine 113 and the associated components of the two-wheeled vehicle 100.
[00027] Fig. 4 (d) shows a balancing system 400-3 of the internal combustion engine in accordance with an embodiment of the present subject matter. For example, the balancing system 400-3, which is a functional system for balancing, of the present subject matter includes a balancer web 306 that acts as a counter weight. The mass of the balancer web 306 may be determined by computation of balancing factor for the IC engine 113. In an embodiment, the mass is suitably distributed between the crankshaft 204 and the balancer shaft 404 to achieve maximum balancing of the primary unbalance forces. In an embodiment, achieving the compactness of balancer system by reducing the length of the balancer shaft 404, and for example, by eliminating the balancer shaft drive gear (not shown), enables using a single ball bearing support 406 for the entire balancer system 401. In one embodiment, compact layout 300 of the IC engine assembly 400-2 is achieved by shortening the length of the crankshaft 204 and by positioning one or more functional system including starter system 201 with bendix drive 304, oil cooling system 301 and balancer system 401 around 360°, which is disposed radially, closer to the at least one crankshaft web OD 206A integrated with the ring gear 402. In one embodiment, the ring gear 402 is integrated to the crankshaft web OD 206B that is disposed towards the crankshaft LH 210. In another embodiment, the ring gear 402 is integrated to the crankshaft web OD 206A that is disposed towards the crankshaft RH 208.
■FI CE CffEMNAT 29 >2B 3^2816 10-49

[00028] Although the subject matter has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. It is to be understood that the aspects of the embodiments are not necessarily limited to the features described herein. Many modifications and variations of the present subject matter are possible in the light of above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.

I/We claim:
1. An internal combustion engine assembly (300, 400-1, 400-2, 400-3)
comprising:
a piston (205) having a reciprocating motion about a cylinder;
a crankshaft (206) coupled to said piston (205) through a connecting rod (212)
that enables conversion of said reciprocating motion into a rotating motion of said
crankshaft (206) and said crankshaft (206) comprises one or more crankshaft
web(s) (206A, 206B); and
one or more functional systems (201, 301, 401) that work in conjunction with said
internal combustion engine assembly (300, 400-1, 400-2, 400-3) and each
functional system (201, 301, 401) of said one or more functional systems (201,
301, 401) includes a driven gear (218, 220,410),
wherein
said crankshaft (206) is provided with at least one ring gear (402) that is provided
on an outer diameter on at least one of said crankshaft web (206A, 206B) and said
ring gear (402) directly engages with at least one of said driven gear(s) (218, 220,
410).
2. The internal combustion engine assembly (300, 400-1, 400-2, 400-3) of claim 1, wherein said functional systems (201, 301, 401) are disposed engagingly radially about said ring gear (402).
3. The internal combustion engine assembly (300, 400-1, 400-2, 400-3) of claim 1, wherein said ring gear (402) is integrated with said crankshaft web (206A) of the crankshaft (206).

4. The internal combustion engine assembly (300, 400-1, 400-2, 400-3) of claim 1, wherein said functional systems (201, 301, 401) includes a starts system (201) comprising a starter motor (202) coupled to a bendix drive (304) and a pinion driven gear (410) of said bendix drive (304) engages directly with said ring gear (402) of said crankshaft (206).
5. The internal combustion engine assembly (400-2) of claim 1, wherein said functional systems (201, 301, 401) includes a oil cooling system (201, 301, 401) and a pump driven gear (220) of said oil cooling system (401) directly engages with said ring gear (402) of the crankshaft (206).
6. The internal combustion engine assembly (400-2, 400-3) of claim 1 further comprises a balancer system (301) comprising a balancer web (306) having balancer shaft driven gear (218) that is directly engaging with the ring gear (402) of the crankshaft (206), whereby said balancer web (306) is disposed in proximity to the crankshaft.
7. The internal combustion engine assembly (400-2, 400-3) of claims 1 or 6, wherein said balancer system (401) enables use of a single ball bearing support (406).
8. The internal combustion engine assembly (300) of claim 1, wherein said ring gear (402) is integrated with said outer diameter of said crankshaft web (206A) on to left hand side of connecting rod (212) that is centrally disposed.

9. The internal combustion engine assembly (400-1) of claim 1, wherein said ring gear (402) is integrated with said outer diameter of said crankshaft web (206B) on to left hand side of connecting rod (212) that is centrally disposed.