DESC:FIELD OF THE INVENTION

The present invention relates to a canister arrangement for a motorcycle.

BACKGROUND TO THE INVENTION
There has been a demand to control emission of fuel vapour (evaporation gas) from a fuel tank of, for example, a motorcycle, in consideration of environmental impacts. To control the emission of fuel vapour, a canister filled with activated carbon for adsorbing fuel vapour is mounted to a motorcycle. The canister stores fuel vapour. The fuel vapour in the canister is redirected to the engine at appropriate time so that emission of fuel vapour from tank to atmosphere is prevented. The engine’s emissions and the motorcycle’s driveability remain largely unaffected.
The canister is connected to a fuel tank via an inlet pipe. The inlet pipe is also known as a charge hose. The inlet pipe provides path for gaseous fuel from fuel tank to canister. The canister thereby adsorbs fuel vapour discharged from the fuel tank breather. The fuel vapour adsorbed by the canister is supplied to engine intake through an outlet pipe (a purge hose), and is burned therein.
When locating a canister on a motorcycle, a few considerations need to be made. Firstly, the canister needs to be away from heat sources such as the engine or the exhaust pipe in order to prevent damage to the canister. Secondly, the canister should not be directly visible so that it does not adversely affect the aesthetics of the motorcycle. Thirdly, it is desirable that the length of the inlet pipe and the outlet pipe connecting to canister is optimised for proper functioning, convenience during assembly and service of the motorcycle.
With these considerations in mind, it is important to identify and locate the canister at a suitable location on a specific motorcycle having a particular type of: (a) frame structure, (b) engine positioning and orientation, and (c) positioning of other motorcycle components such as air filter, fuel intake components, shape and structure of fuel tank etc. Furthermore, it is also important that the location of the canister arrangement does not adversely affect or compromise other layouts and systems of the motorcycle.
Therefore, it is always challenging for a motorcycle designer to identify a suitable location for a canister when faced with the aforementioned considerations for mounting the canister and limitations of a specific motorcycle.
The challenge is intensified if the canister is to be located on an existing motorcycle design. Locating a canister on an existing motorcycle design without adversely affecting the aesthetics of the motorcycle and without redesigning of other components is particularly problematic. Redesigning of the motorcycle and repositioning of the components to accommodate a canister is costly.
There are various prior art documents describing the location of the canister on a specific motorcycle. These prior art documents disclose solving problems related to specific type of motorcycle frame, and specific design and layout of engine and other components of motorcycle.
The present invention addresses the problem of locating a canister position for a motorcycle having a frame structure, engine orientation, and layout of other systems of the motorcycle.
It is an object of the present invention to provide a canister arrangement for motorcycle such that the canister is located away from heat sources.
It is a further object of the present invention to locate a canister on a motorcycle such that the canister is at least partially hidden that is the canister is not visible directly. Ideally, the arrangement is such that the aesthetic appearance of vehicle is unaffected as well as the canister is adequately protected.
It is a further object of the present invention to locate a canister on a motorcycle such that the total length of the inlet tube and the outlet tube are optimised.
It is a further object of the present invention to locate a canister without compromising the placement or positioning and space requirements of other sub systems or systems of the motorcycle.
It is also an object of the present invention to mount a canister arrangement over the frame structure of a motorcycle considering the above objectives.

DESCRIPTION OF THE INVENTION
With the aforementioned problems and objectives in mind, an aspect of the present invention provides a motorcycle including:
a frame structure;
an engine mounted on the frame structure;
a swing arm having a right arm portion and a left arm portion, a first end of the swing arm pivotally connected to the frame structure and a second end of the swing arm fixedly connected to a rear wheel such that the second end moves along with vertical movement of the rear wheel; and a canister for adsorbing fuel vapours generated in the fuel tank and delivering the fuel vapours to the engine, wherein the canister is located rear of the engine and at least partly disposed in a space between said swing arm portions.
The canister is advantageously located in the space with clearance from the swing arm portions so that the swing arm does not contact the canister during suspension movement of motorcycle i.e. pivotal movement of the swing arm. The arrangement prevents compromising the suspension characteristics, for example the suspension stroke, of the motorcycle and avoids hitting the swing arm against the canister during full bump or stroke condition. Also, the arrangement does not require additional protective cover for the canister.
Importantly, the canister is located far away from the engine’s heat zone, which is the volume surrounding the engine’s cylinder head. Therefore, the canister is at a safer location.
The canister may be mounted on the frame structure. Preferably, the frame structure includes a rear lower portion connected to a rear upper portion of the frame structure and a front portion of the frame structure, and the canister is mounted on the rear lower portion.
The space between the front portion and the rear lower portion is typically used for mounting other motorcycle components such as air filter. An air filter is provided for cleaning intake air for the motorcycle engine. A clearance between air filter and canister is sufficient to avoid reduction of the air filter volume which would result in lesser cleaning efficiency.
A mounting means may be provided for mounting the canister to the frame structure. Preferably, the mounting means includes a rigid member attached to the frame structure and a resilient member securing the canister to the rigid member. Rigid member can be welded to frame or can be a loose part fastened to the frame.
By using a resilient member: (a) damage to the outer shell of the canister due to fastening is prevented, and (b) the number of components of the mounting means are reduced. Further use of resilient mounting scheme reduces possibility of vehicle vibrations transferred to canister thereby decreasing the chance of charcoal degradation(powder formation).
The swing arm may include a transverse member joining said swing arm portions, the transverse member located between the first end of the swing arm and the rear wheel, and wherein the canister does not contact the transverse member during pivotal movement of the swing arm.
The clearance from the transverse member helps prevent compromise in the suspension characteristics of the motorcycle. Firstly, the transverse member strengthens the swing arm. Therefore, discarding or weakening (by cutting out a portion of the transverse member to accommodate the canister) the transverse member is not viable for many motorcycle models. Secondly, limiting the full bump condition of the rear suspension to prevent damage to the canister or canister mounting means is not required in the present arrangement. The swing arm including the transverse member can be moved freely without damaging the canister.
The canister inlet and outlet may be positioned to a side of the motorcycle such that an inlet conduit connecting the fuel tank to the canister inlet and an outlet conduit connecting the canister outlet to the engine are passed over the side of the motorcycle. The conduits could be passed over the left hand side of the motorcycle or the right hand side of the motorcycle. Moreover, alternatively one of the conduits is passed over a side of the motorcycle and the other conduit is passed over the opposite side of the motorcycle.
Advantageously, the installation of the inlet and outlet conduits is simplified as other (existing) components of the motorcycle do not need to be disturbed when the conduits are passed over a side of the motorcycle.
The canister position is such that the hose connection from tank to canister does not have any chance to accumulate liquid fuel which can possibly create a vapour lock and thus preventing need of any additional arrangement to drain that accumulated fuel i.e. the inlet point of canister is at lower most position and the hose connection does not create any bend or twist thus allowing any chance to accumulate liquid fuel in the inlet path.
The canister may be located below an air filter.
The frame structure may be a half duplex cradle frame structure. However, the arrangement is not limited to this type of frame structure. The arrangement could also be used with other types of frame structures such as single cradle, full cradle, double cradle, backbone, beam, pressed or trellis frame structure.
The rear suspension of the motorcycle may include a single mono-shock absorber or two shock absorbers.
In case of mono-shock absorber, the lower mounting point of shock absorber is on the swing arm. The mounting point is distant to the connection between swing arm and connected rear wheel. The mounting point may be situated at the transverse member of the swing arm.
In case of two shock absorbers, the lower mounting point of each shock absorber is also on the swing arm. However, the mounting point is proximate to connection between swing arm and connected rear wheel.
Other features, elements, steps, characteristics and advantages of the present invention will become apparent from the following detailed description of preferred embodiments of the present invention made with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail by way of example with reference to the embodiments shown in the figures below.
Figure 1 is an isometric view of motorcycle frame illustrating canister arrangement according to an embodiment of the present invention.
Figure 2 is a another isometric view of the motorcycle frame illustrating canister arrangement according to an embodiment of the present invention.
Figure 3A is a left side view of the canister arrangement of Figure 1 illustrating position of the swing arm while rear wheel is in air condition.
Figure 3B is a left side view of the canister arrangement of Figure 1 illustrating position of the swing arm while rear wheel is in full bump condition.
Figure 3C depicts view of figure 3A with engine mounted condition.
Figure 4A is a left side view of the canister arrangement of Figure 1 illustrating the mounting means
Figure 4B is an enlarged isometric view of the canister arrangement of Figure 4A.
Figure 4C is an enlarged top view of the canister arrangement of Figure 4A.
Figure 4D is an enlarged left side view of the canister arrangement of Figure 4A.
Figure 5A is an isometric view of the canister arrangement of Figure 1 illustrating the conduit disposition.
Figure 5B is a rear view of the canister arrangement of Figure 5A.
Figure 6A is isometric view of motorcycle A having the canister arrangement of Figure 1.Figure 6B is a left side view of the motorcycle of Figure 6A.
Figure 7 is a left side view of motorcycle B having the canister arrangement of Figure 1.
Figure 8 is an isometric view of motorcycle B illustrating two alternative embodiments of canister arrangement.
Figure 9 is an isometric view of another motorcycle illustrating canister arrangement.
Figure 10 is a left side view of motorcycle having the canister arrangement of Figure 9.

REFERENCE NUMBER TABLE
No. Feature
10 Frame structure
12 Head pipe
14 Main pipe
16 Down pipe
18 Front lower pipe
19 Cross pipe
20 Rear upper pipe
22 Rear lower pipe
30 Swing arm
32 Left arm portion
34 Right arm portion
36 Transverse portion
38 Shock absorber
40 Mounting means
41 Attachment portion
42 Rigid member
43 Lip portion
44 Resilient member
50 Canister
52 Canister inlet
54 Canister outlet
56 Inlet conduit
58 Outlet conduit
60 Air filter
62 Engine
64 Fuel tank
70 Rear wheel
100 Motorcycle A
200 Motorcycle B

DESCRIPTION OF PREFERRED EMBODIMENT
Referring to figure 1, the canister arrangement of an embodiment of the present invention includes a frame structure 10, an engine 62 (seen in figure 6A and 6B), a swing arm 30 and a canister 50.
The frame structure 10 is a half duplex cradle frame having a front portion and a rear portion.
The front portion of the frame structure 10 includes a head pipe 12, a main pipe 14, a down pipe 16, two front lower pipes 18 extending from the rear end of the down pipe 16, and a cross pipe 19 transversely connecting the two front lower pipes 18. At their front ends, the main pipe 14 and the down pipe 16 are connected to the head pipe 12. The rear lower end of the main pipe 14 is attached to the cross-pipe 19. The engine 62 (seen in figure 6A and 6B) is mounted on the two front lower pipes 18 and supported by the down pipe 16.
The rear portion of the frame structure 10 includes two rear upper pipes 20 extending from the upper portion of the main pipe 14, and two rear lower pipes 22 connecting the rear upper pipes 20 to the lower portion of the main pipe 14.
The various pipes of the frame structure 10 are generally tubular. The inner and outer profiles of the pipes are generally round. Each pipe is bent to a specific purposive shape. The pipes are welded to each other to form a fixed frame structure 10. Sometimes the above mentioned pipes are referred to as tubes, for example down tube, rear upper tube, etc.
The swing arm 30, at its front end (first end), is pivotally connected to the frame structure 10. The swing arm 30, at its rear end (second end), is fixedly connected to a rear wheel 70 (seen in figure 6A and 6B). Vertical movement of the rear wheel 70 relative to the frame structure 10 is permitted because of pivoting of the swing arm 30 relative to the frame structure 10.
The swing arm 30 includes a right arm portion 34, a left arm portion 32 and a transverse portion 36 joining the right arm portion 34 and the left arm portion 32. The front ends (first ends) of the right arm portion 34 and the left arm portion 32 are pivotally connected to the frame structure 10. The rear ends (second ends) of the right arm portion 34 and the left arm portion 32 are fixedly connected to a rear wheel 70 (seen in figure 6A and 6B). The transverse portion 36 is positioned between the rear lower end of main pipe 14 and the rear wheel 70 (seen in figure 6A and 6B). The transverse portion 36 performs two functions: (1) strengthens the swing arm 30 and (2) ensures that the right arm portion 34 and the left arm portion 32 move in tandem.
The canister 50 is located rear of the engine 62 (seen in figure 3C). In particular, the engine 62 is positioned forward of the lower portion of the main pipe 14, whereas the canister is positioned rearward of the lower portion of the main pipe 14. Additionally, the canister 50 is located between the rear lower end of main pipe 14 and the transverse portion 36 of the swing arm 30. At this location the canister is sufficiently distant from the heat zone of the engine 62, which is mainly surrounding the cylinder head of the engine 62.
The canister 50 is partly disposed in a space between the right arm portion 34 and the left arm portion 32 of the swing arm 30. This space is generally unutilised in a majority of motorcycle designs. The inventors have found that this space could be utilised for positioning the canister 50 because the canister 50 is of a size which can be located in this space. Importantly, functioning/positioning of other components of a motorcycle is not adversely affected or disturbed by locating the canister in said position (more detail below, with reference to figures 3A and 3B).
The canister 50 can be mounted substantially vertical or inclined to vertical or substantially horizontal or inclined to horizontal along the motorcycle longitudinal or width direction.
The canister 50 is located directly below the air filter 60. The canister 50 does not occupy any space between the main pipe 14 and the rear lower pipes 22. This entire space may be dedicated for mounting the air filter 60. Consequently, the volume (and efficiency) of the air filter 60 do not need to be reduced to accommodate the canister 50 on the motorcycle 100 (seen in figure 6A and 6B).
Canister 50, as shown, has an oblong plan section. However, the canister 50 could have another external shape, for example, cylindrical, conical and so on.
In figure 2, the canister 50 appears to be overlapping the right arm portion 34. However, this is only due to limitation of the CAD software used for preparing figure 2, and is to be ignored. In fact, the canister 50 is disposed in the space between the arm portions 32, 34 of swing arm, more particularly towards front end of arm portions. .
Referring to figures 3A and 3B, there are provided two shock absorbers 38 to dampen the jerks produced when riding the motorcycle 100 on an uneven surface. Lower end of each shock absorber 38 is attached to an arm portion 32 or 34 of the swing arm 30. Upper end of each shock absorber 38 is attached to the frame structure 10.
The vertical movement of the rear wheel 70 relative to the frame structure 10 is constrained by maximum extension and contraction of the shock absorbers 38. When the rear wheel 70 is not supported by the ground surface (for example motorcycle is on centre stand), the shock absorbers 38 reach maximum extension as seen in figure 3A. This is the ‘in air condition’ of the rear wheel 70. As the wheel 70 is moves upwards relative to the frame structure 10 during running condition, the shock absorbers 38 progressively contract to a point where the shock absorbers 38 cannot be contracted any further as seen in figure 3B. This is the ‘full bump condition’ of the rear wheel 70.
The canister 50 located rear to the engine 62 (seen in fig 6A and 6B) and disposed in the space between the arm portions 32, 34 of the swing arm 30, does not contact any portion 32, 34, 36 of the swing arm 30 or the rear wheel 70 when the swing arm is in the air condition (fig 3A), the full bump condition (fig 3B) or between the air condition and the full bump condition. Furthermore, the arrangement is such that there may be additional clearance provided from the components which may contact the canister 50 if excessive force is exerted on them. Therefore, the canister 50 does not require additional shielding to be safe from the movement of the swing arm 30 or the components directly attached to the swing arm 30. Advantageously, the arrangement does not put restrictions on the full bump condition of the shock absorbers 38. The shock absorbers 38 can operate between their originally designed range - extension and contraction. There is no requirement to compromise the suspension characteristics of the swing arm 30 in order to avoid contact and impact of swing arm 30 against canister 50, by the swing arm 30, during full bump condition.
Referring to figures 4A, 4B, 4C and 4D, the canister 50 is mounted on the frame structure 10. The mounting means includes a rigid member 42 and a resilient member 44. The mounting means does not require any particular modification to the frame structure 10. Rigid member 42 can be welded to frame 10 or can be a separate part fastened to the frame 10.
The rigid member 42 is a sheet metal part. One side of the rigid member 42 is an attachment portion 41, whereas the other side is a lip portion 43. The attachment portion 41 is welded onto the two rear lower pipes 22 of the frame structure 10 such that the rigid member 42 joins the two rear lower pipes 22 substantially at their lower end.. The lip portion 43 extends upwardly.
The resilient member 44 is a loop of durable elastic material. The canister 50 is securely held on the lip portion 43 by tensely passing the resilient member 44 around the canister 50 and the lip portion 43. The resilient member 44 is a rubber strap. Lip portion 43 restricts the resilient member 44 from being released.
The canister 50 is mounted such that the canister 50 is substantially central and symmetric to the vertical plane. Therefore, the canister is located equidistant from each arm portion 32, 34 of the swing arm 30.
Once the canister 50 is mounted on the frame structure 10, the canister inlet 52 and the canister outlet 54 are positioned to the right hand side of the motorcycle 100 (seen in fig 5A and 5B).
Referring to figures 5A and 5B, the arrangement further includes an inlet conduit 56 and an outlet conduit 58. The inlet conduit 56 connects the fuel tank 64 (seen in figures 6A and 6B) to the canister inlet 52. The outlet conduit 58 connects canister outlet 54 to the intake system of engine. Fuel vapours from the fuel tank 64 are passed through the inlet conduit 56 to the canister 50 and adsorbed in the canister 50. Fuel/fuel vapours stored in the canister 50 are timely delivered to the engine 62 (though the outlet conduit 58. As the canister inlet 52 and the canister outlet 54 are positioned to the right hand side of the motorcycle 100, the conduits 56, 58 can be passed around the existing components of the motorcycle 100 (Therefore, the existing systems of a motorcycle 100 do not need to be disturbed to install the inlet conduit 56 and the outlet conduit 58.
Referring to figure 6B, the proposed canister arrangement on motorcycle A 100 substantially hides the canister 50 from view. Thus not affecting aesthetics of the motorcycle and therefore, additional covers are not required for concealing the canister 50 from view. Also, the aero dynamics of the motorcycle are not compromised by the proposed canister arrangement.
Referring to figure 7, the proposed canister arrangement on motorcycle B 200 also substantially hides the canister 50 from view. Therefore, additional covers are not required for concealing the canister 50 from view on motorcycle B 200.
Referring to figure 9 and 10, it discloses the mounting of canister 10 on the motorcycle with double cradle type frame 10.
It is be noted however beyond half duplex cradle and double cradle type as described in preferred embodiments the frame structure may also be single cradle type, full cradle, back bone, beam, pressed or trellis type of frame structure.

ALTERNATIVE EMBODIMENTS
The canister 50 may be mounted on the swing arm 30. Referring to figure 8, the canister 50 may be mounted on the frame structure 10 at two alternative positions. Firstly, the canister 50 may be located above the cylinder head of the engine 62. Secondly, the canister 50 may be mounted on the rear upper pipes 20, that is, under the seat (not shown in figure 8). Although the two alternative locations may not have all the advantages of the preferred embodiment, the alternative locations may be suited for a motorcycle where the preferred embodiment is not readily adaptable.
The motorcycle 100 may include a mono-shock absorber and/or a centrally located muffler.
Modifications and variations to the motorcycle of the invention may be apparent to the skilled reader of this disclosure. Such modifications and variations are deemed within the scope of the present disclosure.
,CLAIMS:1. A motorcycle including:
a frame structure;
an engine mounted on the frame structure;
a pivotable swing arm having a right arm portion and a left arm portion, a first end of the swing arm pivotally connected to the frame structure and a second end of the swing arm fixedly connected to a rear wheel such that the second end moves along with vertical movement of the rear wheel; and
a canister for adsorbing fuel vapours generated in the fuel tank and delivering the fuel vapours to the engine,
wherein the canister is disposed at rear of the engine and at least partly disposed in a space between said swing arm portions.
2. The motorcycle as claimed in claim 1, wherein the said canister is mounted on the said frame structure of the motorcycle.
3. The motorcycle as claimed in claim 2, wherein the said frame structure includes a rear lower portion connected to a rear upper portion of the frame structure and a front portion of the frame structure, and the canister is mounted on the rear lower portion of the frame structure.
4. The motorcycle as claimed claim 3, wherein the canister is located lower to the rear lower portion of the frame structure such that the space between the front portion and the rear lower portion of the frame structure is not occupied by the canister.
5. The motorcycle as claimed in claims 2 to 4, wherein the said canister is mounted with a mounting means on said frame structure of the motorcycle.
6. The motorcycle as claimed in claim 5, wherein the canister is mounted substantially vertical or inclined to vertical or substantially horizontal or inclined to horizontal along the motorcycle longitudinal or width direction.
7. The motorcycle as claimed in claim 5, wherein the said mounting means includes a rigid member attached to the frame structure and a resilient member securing the canister to the rigid member, wherein the said rigid member may be a welded part of the frame or may be a member fastened onto the frame.
8. The motorcycle as claimed in claim 1, wherein the swing arm includes a transverse member joining the said swing arm portions, and the transverse member located between the first end of the swing arm and the rear wheel, and said canister disposed such that the canister does not contact the transverse member during pivotal movement of the said swing arm.
9. The motorcycle as claimed in claim 1 to 8, wherein the inlet conduit connecting fuel tank of the motorcycle to the canister inlet and an outlet conduit connecting the canister outlet to the engine of the motorcycle are arranged to pass along the same side of the motorcycle.
10. The motorcycle as claimed in claim 1 to 8, wherein the inlet conduit connecting fuel tank of the motorcycle to the canister inlet and an outlet conduit connecting the canister outlet to the engine of the motorcycle are arranged to pass along the opposite sides of the motorcycle.
11. The motorcycle as claimed in claim 4, wherein the canister is disposed lower to the rear lower portion of the frame structure and below an air filter mounted between the front portion and the rear lower portion.
12. The motorcycle as claimed in claim 1, wherein the frame structure maybe a half duplex cradle frame structure, a single cradle frame structure, a full cradle frame structure, a double cradle frame structure, a backbone frame structure, a beam frame structure, a pressed frame structure or a trellis frame structure..
13. The motorcycle as claimed in claim 1, wherein the said motorcycle may include a rear suspension which maybe a single mono-shock absorber or a set of two shock absorbers.