Description:FIELD OF THE INVENTION
[0001] The present invention relates to a canister arrangement for a motorcycle, and particularly but not exclusively to a canister arrangement for a scooter-type motorcycle.
CROSS REFERENCE
[0002] This application is a divisional application of the original application number 2768/MUM/2014 filed previously on 21-August-2014.
BACKGROUND TO THE INVENTION
[0003] There has been a demand to control emission of fuel vapour (evaporation gas) from a fuel tank assembly 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 fuel tank assembly to atmosphere is prevented. The engine’s emissions and the motorcycle’s driveability remain largely unaffected.
[0004] The canister is connected to a fuel tank assembly 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 assembly to canister. The canister thereby adsorbs fuel vapour discharged from the fuel tank breather. The fuel vapour adsorbed by the canister is supplied to the engine intake through an outlet pipe (a purge hose), and is burned therein.
[0005] 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.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] The present invention seeks to address the problem of locating a canister position for a motorcycle having a frame structure, engine orientation, and layout of other systems of the motorcycle.
[0011] It is an 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.
[0012] It is a further object of the present invention to provide a canister arrangement for motorcycle such that the inlet pipe and the outlet pipe of the canister have an optimised length.
[0013] 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.
[0014] It is also an object of the present invention to mount a canister arrangement over the frame structure of a motorcycle, including a scooter-type motorcycle, considering the above objectives.
SUMMARY OF THE INVENTION
[0015] With the aforementioned problems in mind, a first aspect of the present invention provides a motorcycle including
a head pipe,
a body frame connected to the head pipe and including a front frame extending downward and rearward from the head pipe and a seat frame at the rear end of the front frame,
an engine mounted on the body frame,
a fuel tank assembly including a fuel tank; and
a canister for adsorbing fuel vapours generated in the fuel tank and delivering the fuel vapours to the engine,
wherein the canister is mounted the fuel tank assembly.
[0016] The motorcycle may be a scooter-type motorcycle.

[0017] The motorcycle may include a mounting means for mounting the canister on the fuel tank assembly. Preferably the mounting means is a bracket attached to the fuel tank assembly.
[0018] Advantageously, direct mounting of the canister on the fuel tank allows stable assembly of the canister and respective fuel tubes. The canister can be fitted on the fuel tank before the fuel tank is mounted on the motorcycle. Therefore, the inlet pipes can be routed easily. The ease of assembly also reduces assembly time and cost. Further, number of parts for mounting the canister is reduced by directly mounting on the fuel tank.
[0019] The fuel tank assembly may include a protrusion for attaching the mounting means to the fuel tank assembly. Preferably, the protrusion is at a parting line of the fuel tank.
[0020] In case of fuel tanks made of moulded plastic, it is possible to add or provide a protrusion during moulding process to mount the canister. Further, locating the protrusion on the parting line makes it easier to create the mould of the plastic fuel tank assembly. The strength of such moulded protrusion can be optimised to hold the canister firmly.
[0021] The motorcycle may include a mounting means for mounting the canister on the fuel tank assembly at a first attachment point. The mounting means may be connected to the body frame or seat frame as well at a second attachment point, and wherein the second attachment point is between the fuel tank and the canister.
[0022] The canister is preferably mounted on the fuel tank in such a way that it uniformly distributes load coming from the canister and the fuel tank on the mounting bracket. Such weight distribution helps keeping the mounting of the fuel tank assembly intact for a longer duration. Further, it reduces the need for additional strength to compensate for the overhang, which would otherwise be created. Further, as the mounting means is used for mounting the fuel tank assembly may be used for mounting canister as well, the canister mass can be at least partly supported on the seat frame rather than on the fuel tank assembly. The common mounting means for the canister and the fuel tank assembly avoids need for separate mounting for each component. Thus reducing the total weight of vehicle.
[0023] Preferably, the canister is positioned:
• proximate to the fuel tank assembly,
• at least partially above the engine,
• at least partially forward of the fuel tank assembly,
• between fuel tank and engine
• outside the seat frame, and/or
• between a side member of the seat frame and a side cover of the motorcycle proximate to said side member.
• at least partially positioned between a right side member of the seat frame and a left side member of the seat frame
• below the seat

[0024] Further, the canister may be positioned in such a way that it does not get exposed to heat radiated by the engine and silencer. Such positioning helps to keep the canister in low temperature zone and prevents deterioration in performance of the canister due to engine and silencer heat.
[0025] The seat frame of the motorcycle, advantageously connected to or formed integrally with the front frame for supporting the seat, the fuel tank assembly and canister, may include an upward extending portion adjoining the front frame and a rearward extending portion adjoining said upward extending portion, and wherein the canister is positioned rearward of said upward extending portion and below said rearward extending portion.
[0026] Advantageously, the canister position utilises available but limited packaging space in a way which avoids modification to the layout of the system or the sub-systems of the motorcycle. Further, the proposed canister positioning by and large does not affect other systems and sub-systems of the motorcycle.
[0027] The side cover is generally optimised for aero-dynamics and/or aesthetics. The canister placed in position remains hidden behind the side cover. Therefore, the aesthetics of the vehicle and/or the aerodynamics of the vehicle, rendered particularly by the side cover, remain unaffected.
[0028] Further advantageously, the canister positioning does not need the volume of the fuel tank or the storage capacity of the helmet box/storage box to be reduced.
[0029] The inlet pipe and the outlet pipe lengths are optimised as the canister is positioned very close to the components from which it takes the fuel vapours that is the fuel tank assembly and proximate to the component to which fuel vapours are delivered i.e. the engine. Reduced length of pipes reduces the risk of condensation of the fuel vapour in the pipes. Further, cost of pipes is also reduced.
[0030] The fuel tank assembly may be is made of plastic material or sheet metal.
[0031] A second aspect of the present invention provides a motorcycle including a canister for adsorbing fuel vapours generated in a fuel tank as well as the fuel filter and delivering the fuel vapours to an engine.
[0032] The motorcycle may include a fuel tank breather and a fuel filter breather connected to a common canister inlet pipe.
[0033] The motorcycle may include a mechanism to restrict liquid fuel entering into the canister. Preferably, the mechanism to restrict liquid fuel is a one-way valve mounted in-line on the canister inlet pipe.
[0034] Advantageously, a common canister and common piping for vapours from fuel tank and fuel filter reduces the number of parts and lengths of inlet pipes required to obtain fuel efficiency.
[0035] In one of the embodiment of the invention, the canister mounted on the fuel tank, is positioned above the engine. Such type of arrangement is convenient for a scooter type of motorcycle where a fuel tank, canister and engine are placed inside a rear vehicular structure commonly known as a bonnet. Position of the canister and the fuel tank above the engine is especially advantageous as it allows better packaging including within a single piece bonnet design. As the canister and the fuel tank are in proximity, length of tubing connecting these parts is substantially reduced. Further, since the fuel tank is positioned above the engine, gravity assists in supplying fuel to the engine without need of a separate pump for fuel supply. This provides a useful cost saving.
[0036] However, packaging of the canister and the fuel tank above the engine can lead to problems related to heat management. As the fuel tank and the canister are positioned above the engine, they are continuously exposed to heat radiated by the engine. Further, engine cooling air after passing over engine gets heated and move upwards towards the engine and the canister.
[0037] Exposure of the canister to engine heat can adversely affect its performance and reduces its efficiency of absorbing fuel vapours. Similarly, exposure of the fuel tank to the engine heat can lead to high fuel temperature, increased fuel vapour generation and cause unsafe condition. These undesirable problems pose issues in positioning the fuel tank and the canister above the engine.
[0038] The heat issues are amplified in case of a scooter type motorcycle where the fuel tank, canister and engine are placed inside an enclosed bonnet which restricts heat transfer away from these parts particularly when the scooter type motorcycle is at a standstill without a cooling airflow as would be experienced during motion. Further, the bonnet also accommodates a rear frame structure of the scooter, air cleaner, intake system, silencer, shock absorber, wiring harness and various cables. Heat management becomes very difficult, especially when the fuel tank and the canister are mounted above the engine. When the scooter is being driven or is stopped after a drive, air inside the bonnet gets heated due to engine heat and moves upward through combined processes of conduction and convection. The heated air remains trapped under the bonnet which affects the canister performance and creates unsafe conditions and risk of damage to the engine.
[0039] To overcome the issue of heat management, an arrangement of a heat shield is advantageously provided. The heat shield is conveniently positioned in between the canister, the fuel tank assembly and the engine. The heat shield does not allow the hot air to reach and excessively heat the fuel tank and the canister. The heat shield generally confines the hot air to the engine region and keeps the fuel tank and the canister isolated from the hot air. In case of scooter type motorcycle, the heat shield may be provided in the confined space of the rear vehicular structure or bonnet disposed between the engine and fuel tank and canister. However, a heat shield may also be used with benefit in other motorcycle constructions.
[0040] The heat shield may act as a suitable mounting arrangement or platform (sub assembly) to support fuel tank and canister and its tubing /connecting arrangements thus offering a very neat packaging solution.
[0041] The heat shield may be fixed to the internal surfaces of the bonnet for support or may be formed as a sub assembly with the fuel tank and disposed in the rear vehicular structure.
[0042] The heat shield can be made of plastic or rubber material. The heat shield may be made of two separate overlapping parts, one made of plastic and one with rubber to improve the heat protection. The heat shield may be provided with deflectors to direct the hot air to appropriate heated air exhaust vents.
[0043] The bonnet, advantageously a single piece bonnet, comprises – integrally formed a front surface, a rear surface and two side surfaces and a top surface. The top surface is substantially a hollow portion for accommodating a seat mounting arrangement. The front surface preferably has an opening at its lower front end which enables easy engine access for servicing. This opening may be provided with a cover. The side portions have openings at rear locations adaptable for accommodating side indicators /lamps. The rear portion may be provided with an opening to accommodate a tail lamp arrangement.
[0044] The top surface of the bonnet may be substantially a hollow portion that receives a storage box and a seat mounting arrangement. When the scooter is in static condition, confined hot air rises up and gets trapped under the storage box compartment. This air cannot exit through exhaust vent(s), typically in the form of a grille, provided on the rear surface of the bonnet in such static condition. This leads to increase in temperature under the seat and storage box. To facilitate the exit of such hot air, which can cause discomfort for a rider, heated air exhaust vents, conveniently louvers, are preferably provided in a dedicated portion of the storage box. For example, the storage box may be provided with an extending substantially planar portion at its rear end relative to the motorcycle. The exhaust vents, for example louvers, may be provided on this rear extending portion.
[0045] A small clearance may be provided between the seat and the storage box portion such that hot air exiting through louvers in the storage box can exit into the atmosphere. Thus the arrangement of exhaust vents, for example louvers, enables heat dissipation even during static condition of the scooter.
A footrest may be provided for the motorcycle. Access to mounting of the foot rest may then conveniently be provided via openings provided for side indicators. Thus mounting arrangement for foot rest assembly is not visible which may otherwise hamper aesthetic looks of the rear vehicular structure.
[0046] Suitable guides or flow channels may be provided on inner surface of the bonnet to facilitate entry and exit of the air. Shape and profile of the internal surfaces of the rear vehicular structure may further assist in guiding the hot air out of the confined space helping in reducing heat in the space. The rear surface of the bonnet is also provided with a grill arrangement that assist in exiting the hot air trapped inside the bonnet when vehicle is in motion.
[0047] The bonnet of the scooter is advantageously formed with metal such as steel which can produce better surface finish and does not get as affected by temperatures/environmental conditions, which can be extreme in India, as polymeric constructions.
[0048] To form an integral rear vehicular structure or bonnet, specific welding techniques such as Cold Metal Transfer (CMT) may be used which allow a high quality finish which effectively hides the join line. Use of such integral rear vehicular structure is counter-intuitive to the trend of using individual plastic molded parts and assembling to the chassis by multiple attachment points. The metallic bonnet with high finish and without join lines improves aesthetics of the scooter type motorcycle.
[0049] Other features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Figure 1 shows a side view of a motorcycle (scooter-type) having canister arrangement according to one embodiment of the present invention in which the fuel tank is made of plastic material.
[0051] Figures 2A to 2D show side views of the motorcycle of figure 1. In each of figures 2A to 2D various components of the motorcycle are hidden.
[0052] Figures 3A to 3D show top views of the motorcycle of figure 1. In each of figures 3A to 3D various components of the motorcycle are hidden.
[0053] Figures 4A to 4F show three-dimensional views of the motorcycle of figure 1. In each of figures 4A to 4F various components of the motorcycle are hidden.
[0054] Figure 5 shows a front view of the motorcycle of figure 1 with some of the motorcycle components hidden.
[0055] Figure 6A to 6C show side top and bottom views of a canister arrangement according to another embodiment of the invention
[0056] Figures 7A to 7C show three different enlarged three-dimensional views of the canister arrangement of figure 1.
[0057] Figures 8A to 8D show three-dimensional views of the motorcycle of figure 1. In each of figures 8A to 8D various components of the motorcycle are hidden.
[0058] Figures 9A to 9C show three-dimensional views of mounting of canister with respect to another embodiment of invention in which the fuel tank is made of sheet metal.
[0059] Figure 10 shows a rear portion of a scooter-type motorcycle including a bonnet in accordance with a further embodiment of the invention.
[0060] Figure 11 shows a side view of the bonnet of Figure 10 forming an enclosure for fuel tank, canister and heat shield.
[0061] Figures 12A to 12F show a range of views of the bonnet shown in Figures 10 and 11.
[0062] Figure 13A shows a side section view of fuel tank assembly, canister and heat shield enclosed by the bonnet shown in Figs 10 to 12F.
[0063] Figure 13B shows, in partial side view, arrangement of engine, heat shield and fuel tank as shown in Figure 13A
[0064] Figures 14A and 14B show the heat shield as an integral component (Figure 14A) and in exploded view (Figure 14B).
[0065] Figure 15A shows a top perspective view of a storage box for use in the scooter-type motorcycle of Figure 10 and including an air exhaust vent arrangement.
[0066] Figure 15B shows a side perspective view of the storage box of Figure 15A.
[0067] Figures 15C and 15D show side section views of the storage box of Figures 15A and 15B.
[0068] Figure 16A shows a side section view of a rear portion of the motorcycle of Figure 10.
[0069] Figure 16B shows a detail in top perspective view of the rear portion of the bonnet of Figure 16A.
[0070] Figure 17A shows a top front perspective view of a footrest fitted to the motorcycle shown in Figures 10 and 16A.
[0071] Figure 17B shows a side view of the footrest of Figure 17A.
[0072] Figure 17C shows a side perspective view of the footrest of Figures 17A and 17B.
[0073] Figure 18 shows a side view of a rear portion of the motorcycle of Figures 10 and 16A showing relative arrangement of footrest, seat frame, rear wheel and rear wheel suspension.
[0074] In the drawings and the description of the preferred embodiment, “up”, “down”, “front”, “rear”, “left”, “right” and variations thereof indicate directions as viewed from the position of a rider riding on a motorcycle. With reference to the above mentioned drawings, the preferred embodiments of the present invention are described below.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0075] Referring to Figures 1 to 18, in one preferred embodiment, the present invention provides a canister arrangement for a scooter-type motorcycle 100.
[0076] The motorcycle 100 has a frame structure on which other components are supported. In particular, the motorcycle 100 has a head pipe 20 to which is attached a body frame 22. The body frame 22 includes a front frame 24 and a seat frame 26. The front frame 24 may be integrally formed with the seat frame 26 or may be separately connected to the seat frame 26. The front frame 24 extends downward and then rearward from the head pipe 20. The seat frame 26 extends upward and then rearward from the front frame 24. The upward extending portion of the seat frame 26 is termed the first portion 27. The first portion 27 is connected to the front frame 24. The rearward extending portion of the seat frame 26 is termed the second portion 28. The seat frame 26 has a curved bend extending between the first portion 27 and the second portion 28. The seat frame 26 has two side members 29a and 29b on either side of the motorcycle 100 which are distanced and connected to each other by cross-members. The members of the body frame 22 such as the side members 29a and 29b and the cross-members are metal tubes welded to each other.
[0077] The seat frame 26 supports the seat 70 and the fuel tank 40, both substantially located above the rear wheel 200 of motorcycle 100. The seat 70 is above the seat frame 26. The seat 70 is of a size to suit two people viz. the rider and the passenger of the motorcycle 100. Fuel tank 40 is mounted on the seat frame 26 at the attachment point 45 (details of fuel tank 40 mounting are provided at a later stage). The fuel tank 40 is positioned below the seat frame 26. Further, the rearmost end of the fuel tank 40 is substantially in line with the rearmost end of the seat frame 26. The forward-most end of the fuel tank 40 is extends till the bend of the seat frame 26.
[0078] The body frame 22 supports the engine 72. The engine 72 is oriented substantially horizontally. The lowermost end of the engine 72 is substantially in line with the rearward portion of the front frame 24. The forward-most end of the engine 72 is substantially in line with the forward-most end of the storage box 74. The engine 72 is mounted on the body frame 22 such that it is rearward of the front frame 24.
[0079] The motorcycle 100 has side covers 76 on either side. The primary function of the side covers 76 is to protect the fuel tank assembly including fuel tank 40. The side covers 76 extend well beyond the fuel tank 40 to cover other systems and sub-systems of the motorcycle 100. The side covers 76 may partially or completely cover the engine 72. The side covers 76 are shaped such that the motorcycle 100 is aesthetically pleasing and has reduced drag when travelling. As the side covers 76 extend forward of the fuel tank, they curve inwards towards the body frame 22.
[0080] Referring to Figures 1 to 2D, a canister 60 for adsorbing fuel vapours emitted from the fuel tank 40 and the fuel filter 50 and delivering the adsorbed vapours to the engine 72 in a timely manner is positioned forward of the fuel tank 40. The canister 60 is positioned directly above the engine 72. It will be appreciated that the positioning of fuel tank 40 above the engine 72 allows a gravity fuel flow to the engine 72 and allows a fuel pump to be omitted with advantageous cost saving. The canister 60 is positioned rearward from the first portion 27 of the seat frame 26 and below the second portion 28 of the seat frame 26. The canister 60 is positioned proximate to the bend between the first portion 27 and the second portion 28 of the seat frame 26.
[0081] Referring to Figures 3A to 3D, the canister 60 is positioned in the space available between the right side cover 76, the fuel tank 40 and the right side member 29 of the seat frame 26. Further, the side cover 76 which is designed to protect the fuel tank 40 is amply suitable to protect the canister 60. So no additional cover is required to protect the canister 60 at this position. Importantly, being at this location, the canister 60 does not gouge in the fuel tank 40 volume or the storage box 74 storage capacity. The canister 60 does not extend sideward beyond the fuel tank 40 in the plan view. The canister 60 is almost adjoining the right side member 29 of the seat frame 26. Further the canister 60 is placed in very close proximity to the fuel tank 40. The canister 60 may be positioned adjoining the fuel tank 40. When the side cover 76 is installed, the canister 60 is completely hidden from view. So, the canister 60 in this position does not affect the aesthetics or the aerodynamics of the motorcycle 100.
[0082] In an another embodiment of the invention as shown in Figures 6A to 6C, the canister 60 is positioned in the space between a right side member 29a of the seat frame 26 and a left side member 29b of the seat frame 26. Further, the canister 60 is placed between the storage box 74 and the fuel tank 40 in the motorcycle longitudinal direction. Preferably, the canister is positioned close to the lateral central point between the storage box 74 and the fuel tank 40. The canister 60 is positioned between rear side of the storage box 74a and in front of the fuel tank. Rear extension of the storage box 74b covers the canister 60 from the top side. Thus provides protection to the canister and no additional protection is required for the canister. Further, various piping arrangements to and from the canister 60 can also be accommodated within the space between the storage box 74 and the fuel tank 48. The canister 60 along with its tubing arrangement is located below the seat 70. Use of the space between the storage box 74 and the fuel tank 48 is unutilized for packaging the canister 60, positioning the canister in that space lead to compact vehicle design. Such positioning keeps the canister 60 away from high heat zone and heat shield may not be required for protecting the canister 60 from the engine and silencer heat. This helps to keep the performance of the canister unaffected due to heat generated by the engine and silencer.
[0083] Referring to Figures 7A to 8D, the canister 60 is mounted directly on the fuel tank 40.
[0084] The fuel tank 40 is provided with a protrusion 42. The protrusion 42 is at the forward-most end of the fuel tank 40. The protrusion 42 is positioned on the fuel tank 40 such that when the fuel tank 40 is placed in its assembly position, the protrusion 42 is substantially adjoining the right side member 29 of the seat frame 26, particularly from the outside of the seat frame 26. Once assembled, the right side member 29 of the seat frame 26 is on one side of the protrusion 42 and the canister is on the other side of the protrusion 42.
[0085] The protrusion 42 has a flat profile and is shaped to be able to carry the requisite fasteners. The protrusion 42 is sized such that it has sufficient strength to mount the canister 60 on the fuel tank 40 at a first attachment point 44 and the fuel tank 40 on the side frame 26. A second protrusion provided at the top rear end of the fuel tank 40 is also for mounting the fuel tank 40 on the seat frame 26.
[0086] The protrusion 42 is at the parting line 46. Having the protrusion 42 at this location makes it easy to mould the fuel tank 40. Previously, the parting line 46(a) used to be located substantially mid-way of the fuel tank as identified in figure 7B.
[0087] A second protrusion 43 is provided at the rear end of the fuel tank assembly 40. The second protrusion 43 also has a first attachment point to the fuel tank assembly. The fuel tank 40 is mounted on to the seat frame 26 by means of fasteners at the attachment points 40A of the protrusion 42 and the second protrusion 43.
[0088] The protrusion 42 is provided with the second attachment point 45 for attaching the fuel tank 40 to the side members 29a and 29b of the seat frame 26 by means of a fastener, such as a bolt. The second attachment point 45 is positioned above the fuel tank 40 so that after assembly, the fuel tank 40 is below the side members 29a and 29b of the seat frame 26. Further, the second attachment point 45 is located such that a major portion of the fuel tank 40 is on one side of the second attachment point 45, whilst the canister 60 is on the other side of the second attachment point 45. Such positioning provides good weight distribution at the second attachment point 45 and reduces the adverse effects of an overhang. Additionally, it also provides durability.
[0089] A canister mounting bracket 62 includes a first member attached to the fuel tank assembly protrusion 42 by means of bracket fasteners at the first attachment point 44 and a two second members for clamping the canister 60 in the first member. The first member and the second members of the bracket 62 are shaped to match the contours of the canister 60. In this case, the canister 60 has a rounded-rectangular cross-section. To match this shape, the first member and the second members of the bracket 62 are substantially U-shaped.
[0090] A fuel filter bracket 51 to mount the fuel filter 50 is attached to the canister mounting bracket 62. The fuel filter 50 is located proximate to the canister 60 so that the length of the canister inlet pipe from the fuel filter breather is reduced.
[0091] The fuel tank 40 has a closure 40A and a fuel tank breather 48. The fuel filter 50 has a fuel filter breather 52. Breathers 48, 52 are positioned at the top of the respective components 40, 50 in order to allow fuel vapours to be emitted easily through the breathers 48, 52. Also, the risk of liquid fuel entering the pipes during regular vehicle running is reduced.
[0092] The fuel tank breather 48 and the fuel filter breather 52 are connected to the canister inlet by pipes. The canister inlet pipe 64 extends between canister inlet and one of the three connections of a T-port 55. A first extension pipe 49 connects the fuel tank breather 48 to the second connection of the T-port 55. A second extension pipe 53 connects the fuel filter breather 52 to the third connection of the T-port 55. Fuel vapours from the fuel tank 40 and the fuel filter 50 are inputted to the common canister 60.
[0093] A one way valve 54 is fitted in line with the canister inlet pipe 64 to restrict the entry of liquid fuel inside the canister.
[0094] At this location, the inputs to the canister 60 are proximate. Therefore, the length of the pipes 49, 53, 64 is reduced. By proper routing of the pipes, the length can be optimised. This helps reduce the risk of condensation in the extension pipes 49, 53, 64. If fuel is condensed in the pipes, it may block the vapour passage to the canister 60 and system of transmitting vapours to the canister 60 will fail. Further, the compactness of this design allows sufficient space for mounting other systems/sub-systems of the motorcycle 100.
[0095] A canister outlet pipe 66 is connected between the canister 60 and engine inlet. Fuel adsorbed in the canister 60 is delivered to the engine by known techniques.
[0096] Referring to Figures 9A to 9C, the main difference between this second preferred embodiment and the above described preferred embodiment is that the fuel tank 40 in the second preferred embodiment is made of sheet metal whereas the fuel tank 40 of the above described preferred embodiment is made of moulded plastic material. The sheet metal fuel tank 40 is a container made of a top portion attached to a bottom portion. The edge between the top portion and the bottom portion extends beyond the container portion of the sheet metal fuel tank 40 forming a peripheral edge portion. There is sufficient seal between the two portions to prevent any leak from the fuel tank 40. The canister mounting bracket 62 is non-intrusively affixed to the top portion of the fuel tank for example by means of an adhesive. The canister 60 is clamped on the canister mounting bracket 62 at a first attachment point 44 as described earlier. The canister mounting bracket 62 has a one-way valve mounting means, located on a side opposite to the canister mounting side, for mounting the one-way valve 54. The canister mounting bracket 62 has a second attachment point 45 at its top. The canister mounting bracket 62 is attached to the seat frame 26 at this attachment point by means of fasteners. Further, the fuel tank 40 has two attachment points located on the peripheral edge region and on an opposite side (i.e. side opposite to where the canister mounting attachment point 44 is located) for mounting the fuel tank to the seat frame 26. So the fuel tank 40 is mounted to the seat frame 26 at three points.
[0097] Also shown in Figures 9B and 9C is a heat shield 146 positioned between the fuel tank assembly including fuel tank 40; and its associated canister 60. The heat shield 146, as shown in particular detail in Figures 14A and 14B comprises a plastic portion 146A and rubber portion 146B which provide insulation to better confine engine heat to the region of engine 72. If the heat shield 146 is made only of plastic then it does not provide enough heat protection and when made of rubber it is unable to hold its shape. Thus, the heat shield 146 plastic portion 146A acts as a stiffener providing support to the rubber portion 146B. Projections 146aa provided on an inner surface of the rubber portion 146b are inserted into holes 146ab provided on periphery of the plastic portion 146A. Further, a rubber deflector plate or baffle 150, of planar shape, is also connected to the plastic portion 146A. The rubber deflector plate 150 has an inclined upward profile for directing hot air away from seat 70 and the storage box 74, advantageously towards a heated air exhaust vent arrangement, for example as described below.
[0098] Heat shield 146 is configured as a mounting arrangement in the form of a platform or sub assembly for the fuel tank assembly including fuel tank 40; and canister 60. The fuel tank assembly including fuel tank 40 is supported on lands 148 and canister 60 (and associated components, on lands 147. Such sub assembly may conveniently be provided as a module to the motorcycle manufacturing facility.
[0099] Heat management issues are amplified in case of a scooter type motorcycle 400, as illustrated with reference to Figures 10 to 18, where the fuel tank 40, canister 60 and engine 166 are placed inside an enclosed bonnet 300, with fuel tank 40 and canister 60 again mounted above the engine 166.
[00100] The bonnet 300 is conveniently attached to, and encloses, seat frame 26 (including members 29a and 29b, the latter of which is shown in Figure 16A) and first portion 27 of the upward extending frame portion 26 by a suitable fastening arrangement (not shown). Bonnet 300, as shown in particular detail in Figures 10 to 12F is made of a plurality of surfaces (side surfaces 310, top surface 315 and rear surface 320) formed integrally with each other, in an aerodynamic shape, forming an enclosure to accommodate various vehicle components including, but not limited to, those mentioned above. Bonnet 300 is formed in a single piece to provide acceptable structural strength and rigidity. To this end, openings in the surfaces 310, 315 and 320 are kept to a minimum, being limited to openings 330 for side indicator lamps and exhaust grille or mesh 340 or an aperture 340a to accommodate the exhaust grille 340.
[00101] When the scooter type motorcycle 400 is being driven or is stopped after a drive, air inside the bonnet 300 gets heated due to engine heat and moves upward through combined processes of conduction and convection. The heated air remains trapped under the bonnet 300 which affects canister 60 performance and creates unsafe conditions and risk of damage to the engine 166.
[00102] To overcome this issue of heat management, a heat shield 146 is again advantageously provided, being positioned in between the canister 60, the fuel tank 40 and the engine 166. As shown in Figures 14A and 14B, heat shield 146 comprises a plastic part 146a and a rubber part 146b with functions as described above.
[00103] The heat shield 146 does not allow the hot air to reach and excessively heat the fuel tank 40 and the canister 60. The heat shield confines the hot air to the engine 166 region and keeps the fuel tank 40 and the canister 60 isolated from the hot air. The heat shield 146 may be fixed to the internal surfaces of the bonnet 300 for additional support. Alternatively, the heat shield 146 may be fully supported on the internal surfaces of the bonnet 300.
[00104] Heat shield 146 is effective. However, heat management in the scooter type motorcycle 400 requires venting of heated air from the confined space under the bonnet 300. A particular issue arises when the scooter-type motorcycle 400 is in static condition, in which case confined hot air rises up and gets trapped under the storage box 74. This air cannot exit through exhaust grille or mesh 340, provided on the rear surface 320 of the bonnet 300 (due to excessive pressure drop) and through which heated air would escape when scooter-type motorcycle 400 is in motion. This would lead to increase in temperature under the seat 70 and storage box 74 which could cause discomfort for a rider. To avoid this problem and facilitate the exit of such hot air, exhaust vents in the form of louvers 74c are provided in the storage box 74. For example, the storage box 74 may be provided with an extending substantially planar portion 74b at its rear end relative to the scooter type motorcycle 400. The louvers 74c are provided on this rear extending portion 74b as conveniently shown in Figures 15A to 15D.
[00105] A small clearance 74e is provided between the seat and the storage box portion 74b such that hot air exiting through louvers 74c in the storage box portion 74b can exit, through a suitable air exhaust arrangement (with sufficiently low pressure drop even in static condition of the scooter-type motorcycle 400) into the atmosphere following the path shown by the arrows of Figure 16D. Thus the arrangement of louvers 74cenables heat dissipation even during static condition of the scooter type motorcycle 400. Suitable guides or flow channels may also be provided on inner surface of the bonnet 300 to facilitate entry through air inlet slots 312; and exit of air heated by the engine 166 at least through the louvers 74c. Shape and profile of the internal surfaces of the bonnet 300, particular its curvature (for example of surface 306 as shown in Figure 12F), also assist in guiding the hot air out of the confined space of the bonnet 300 through louvers 74c. The upwardly inclined surface 74d of storage box 74 also assists in such directing of hot air towards the louvers 74c.
[00106] Some further features of the bonnet 300 are now described. The top surface 315 includes a hollow portion 305 suitable for accommodating a seat mounting arrangement as well as storage box 74. The front surface 302 has an opening 350 at its lower end Hollow portion 350 is covered with a separate removable part (not shown). The opening 350 of the bonnet 300, whenever uncovered, gives easy access to engine 166 and facilitates engine servicing.
[00107] A footrest (such as a sari guard) 290 may be provided for the scooter-type motorcycle 400. The footrest 290, shown in particular detail in Figures 16A to 18 and which may be supplied as an independent part, comprises a frame 292 with a mounting plate 291 at one end and a footrest plate 295 at the other end.
[00108] Access for mounting of a footrest 290 is conveniently provided via openings 330 provided for side indicators. When a footrest 290 is required, an opening 330 is uncovered and the mounting plate 291 of footrest 290 is aligned with a corresponding bracket 291B fixed to seat frame member 29b and fixed into place with bolt fasteners 291A. The same procedure would be repeated on the other side of the scooter-type motorcycle 400 so that two footrests 290 are provided.
[00109] When assembly of footrests 290 to scooter-type motorcycle 400 is complete, the footrest plate 295 should be stably fixed in position above a hub of rear wheel 200 and below the rear wheel suspension spring 202. Aesthetics of the scooter-type motorcycle 400 are enhanced by having footrest frame(s) 292 and mounting arrangement 291, 291A hidden by side surfaces 310 of bonnet 300.
[00110] The bonnet 300 is formed with metal such as steel which can produce better surface finish and does not get as affected by temperatures/environmental conditions, which can be extreme in India, as polymeric constructions.
To form an integral bonnet structure, specific welding techniques such as Cold Metal Transfer (CMT) may be used which allow a high quality finish which effectively hides the join line. Use of such an integral bonnet structure is counter-intuitive to the trend of using individual plastic molded parts and assembling to the chassis by multiple attachment points. The metallic bonnet 300 with high finish and without join lines improves aesthetics of the scooter type motorcycle 400.It is understood that variations and modifications to the preferred embodiment will be apparent to those skilled in the art without departing the scope and the spirit of the present invention. For example, the motorcycle could include a canister of a different shape. For example, a cylindrical canister may be accommodated by making simple modifications to the mounting bracket such that it is suitable to hold the cylindrical canister in place. The scope of the present invention is to be determined by the following claims.
REFERENCE NUMBER TABLE
No. Feature
20 Head pipe
22 Body frame
24 Front frame
26 Seat frame
27 First portion of the seat frame
28 Second portion of the seat frame
29 Side member of the seat frame
29a Right side member of the seat frame
29b Left side member of the seat frame
40 Fuel tank
40A Fuel tank closure
42 Protrusion
43 Second protrusion
44 First attachment point
45 Second attachment point
46 Parting line
46(a) Prior art parting line
48 Fuel tank breather
49 First extension pipe
50 Fuel filter
51 Fuel filter mounting bracket
52 Fuel filter breather
53 Second extension pipe
54 One-way valve
55 T-port
60 Canister
62 Canister mounting bracket
64 Canister inlet pipe
66 Canister outlet pipe
70 Seat
72 Engine
74 Storage box
74a Rear end of storage box
74b Rear extension of storage box
74c Louvers
74d Bottom surface of storage box
74e Clearance between seat and storage box portion 74b
76 Side Cover
100 Motorcycle (scooter-type)
146 Heat shield
146a Plastic portion
146b Rubber portion
146aa Projections
146ab Holes
147, 148 Support land
150 Rubber deflector plate
166 Engine
200 Rear wheel
202 Suspension spring
290 Footrest
291 Mounting plate
291A Bolt fastener
291B Bracket
292 Footrest frame
295 Footrest plate
300 Bonnet
302 Front surface
305 Hollow portion in top surface
306 Internal surface of bonnet
310 Side surfaces
312 Air inlet slots
315 Top surface
320 Rear surface
330 Side indicator opening
340 Grille
340a Aperture for grille
350 Opening on front surface
400 Scooter type motorcycle

, C , Claims:1. A rear vehicular structure for a scooter comprising;
a body frame (22) including a front frame (24) extending downward and rearward and a seat frame (26) at the rear of the front frame (24);
an engine (72) mounted on the body frame (22);
a fuel tank (40) mounted on the body frame (22); and
a bonnet (300) mounted on the body frame (22) and covering at least the engine (72) and the fuel tank (40);
wherein the bonnet (300) is consisting of an integrally formed aerodynamic shape, a front surface (302), a rear surface (320) and two side surfaces (310) and a top surface (315) wherein the bonnet is provided with plurality of flow channels at an internal surface (306) of the bonnet to facilitate entry and exit of hot air generated from engine (72).

2. The rear vehicular structure as claimed in claim 1, wherein shape and profile of the internal surface (306) of the bonnet assists in guiding the hot air out of the bonnet (300).

3. The rear vehicular structure as claimed in claim 1, wherein the rear surface (320) of the bonnet is provided with a grille (340) or mesh to allow hot air to exit.

4. The rear vehicular structure as claimed in claim 1, wherein the top surface (315) of said bonnet is substantially a hollow portion adaptable to receive a storage box (74) and seat mounting arrangement.

5. The rear vehicular structure as claimed in claim 1, wherein the side portions (310) of said bonnet have openings (330) at rear locations adaptable for accommodating side indicators /lamps.

6. The rear vehicular structure as claimed in claim 1, wherein the side portions (310) of said bonnet are fitted with a footrest (290) and access to a mounting for said footrest (290) is provided via openings provided for the side indicators.

7. The rear vehicular structure as claimed in claim 1, wherein the rear portion (320) of said bonnet is provided with an opening to accommodate a tail lamp arrangement.

8. The rear vehicular structure as claimed in claim 7, wherein the tail lamp arrangement is formed as subassembly with the rear portion (320) of said bonnet.

9. The rear vehicular structure as claimed in claim 1, wherein a canister (60) is mounted on the fuel tank (40).

10. The rear vehicular structure as claimed in claim 1, wherein a heat shield (146) is positioned between the fuel tank (40) and the engine (72) preventing the flow of hot air from the engine (72) towards the fuel tank (40).

11. The rear vehicular structure as claimed in claim 10, wherein the heat shield (146) is having a lower surface consisting of guide means for directing hot air towards at least one exhaust vent.

12. The rear vehicular structure as claimed in claim 11, wherein said guide means is a deflector plate (150).

13. The rear vehicular structure as claimed in claim 12, wherein said deflector plate (150) of said heat shield (146) has an inclined upward profile for directing hot air towards said at least one exhaust vent.

14. The rear vehicular structure as claimed in claim 13, wherein a storage box (74) is provided with exhaust vents, such as louvers, to allow hot air exit.

15. The rear vehicular structure as claimed in claim 14, wherein the storage box (74) has a rear extending portion in which louvers are provided to allow hot air exit.

16. The rear vehicular structure as claimed in claim 10, wherein the heat shield (146) provides support to a canister (60) and its tubing /connecting arrangements.

17. The rear vehicular structure as claimed in claim 10, wherein the heat shield (146) is formed as a subassembly with the fuel tank (40).

18. The rear vehicular structure as claimed in claim 10, wherein the heat shield (146) is made of plastic or rubber material.

19. The rear vehicular structure as claimed in claim 18, wherein the heat shield (146) is made of two separate overlapping parts, one made of plastic (146a) and one with rubber (146b) to improve the heat protection.

20. The rear vehicular structure as claimed in claim 1, wherein the bonnet (300) is formed with metal such as steel.

21. The rear vehicular structure as claimed in claim 1, wherein various surfaces of the bonnet (300) are connected by Cold Metal Transfer (CMT).