Description:Technical Field of Invention
[0001] The present subject matter relates to a vehicle, more specifically the present subject matter is related to a fuel tank of the vehicle.

Background
[0002] A vehicle generally consists of a chassis fixed on two or more rolling wheels, where at least one wheel is driven by a engine. The engine can be an internal combustion engine, or an electric motor. An internal combustion engine consists of a carbon-based fuel being burned in a combustion chamber under high pressure. The force being generated by the combustion drives a piston, which in turn drives a crankshaft, which is then transferred to the driven wheel. A lot of heat is generated in this process, and while some of it is converted into rotational motion of the crankshaft, a lot of the energy generated escapes from the combustion chamber, increasing the temperature of the engine, and especially the combustion chamber. A engine therefore has to be efficiently cooled in order to prevent the heat from affecting other parts of the vehicle, or even the users of the vehicle.
[0003] The common carbon based fuels used in road vehicles are petrol and diesel. Other vehicles, such as aircrafts or sea vessels, may use other kind of carbon based fuels as well. Since the fuel is in liquid form, the fuel has to be stored in a sealed container so that the fuel is not lost, or evaporated during the motion of the vehicle. Also, since the fuel is highly combustible, it needs to be protected from any source of heat in close proximity. One such source of heat is the engine. In order to prevent any incidents, the engines have inbuilt cooling mechanisms. The engines may be air cooled or liquid cooled. In air cooled engines, air flow is directed over the engine so that as the vehicle moves forward, the air flow over the exposed surface of the engine cools it down. In liquid cooled engines, a coolant liquid is directed into a cooling circuit designed in the engine, which extracts the heat from the engine itself. The coolant liquid is further cooled externally using a radiator.
 
Summary of the Invention
[0004] Even though the engine may be sufficiently cooled by one of the many cooling methods to prevent large dissipation of heat to cause any serious problems, it may still dissipate enough heat which may affect the user of the vehicle. Generally in a saddle type two wheeled vehicle where usually the rear wheel is the driven wheel, the engine is placed in a forward part of the vehicle, at a height so that the centre of axis of the crankshaft of the engine is substantially aligned with the centre of axis of the rear wheel in a rest state of the vehicle. The fuel tank is generally disposed above the engine. This is because fuel can either be pumped into the engine from the fuel tank using a fuel pump, or it can be fed into the engine by using gravity. The riders’ seat is usually disposed directly behind the fuel tank. This gives better ergonomics for the rider, and in general a more stable riding position. In most saddle type vehicles, in a riding condition, a large part of the rider’s body is in close proximity to the engine, and therefore susceptible to the heat generated by the engine. Specifically, in a riding condition of the vehicle, the rider’s knees and thighs are generally placed in very close proximity to the engine. Since the seat is disposed directly behind the fuel tank, the rider sits right behind the tank, which is made of metal. The heat generated by the engine below the engine, therefore affects the lower body of the rider, specifically the thighs and knees, being transmitted through the fuel tank. This causes discomfort to the rider. Further, the fuel tank being metallic, also absorbs atmospheric heat and becomes hot to touch, and is also uncomfortable to the rider. While problems like that are addressed in existing prior art documents by providing layers of heat resistive materials on the external surface of the fuel tank. However, the heat generated by the engine aggravates the problem.
[0005] Existing prior art documents have also considered the heat generated by the engine right below the fuel tank as being a potential problem to be addressed. In an existing prior art document, it is provided that a plastic tray is disposed below the fuel tank and a canister, which acts as a heat shield for the canister. In another prior art document, a heat shield apparatus made of glass fibre or thermally resistive plastic resin is hot pressed on the bottom side of the fuel tank. In yet another prior art document, a heat shield part which is specifically configured for that purpose, is mounted below the fuel tank, but not mounted to the fuel tank. In yet another prior art document, a heat guard member is provided between a regulator which is also a heat generating member, and the lower portion of the fuel tank.
[0006] All the methods disclosed in the prior art documents involve a complexity of implementation and assembly, require custom parts, separate mountings, and are generally cost intensive. However, none of the prior art documents disclose that a heat shield is configured to protect the rider from discomfort during a riding condition due to the fuel tank being hot. Specifically, none of the prior art documents address the issue of the rider’s discomfort due to the heat generated by the engine.
[0007] In view of the above, there is a need for a heat shield below the fuel tank which will protect the rider from discomfort caused by the heat generated by the engine.
[0008] In one aspect, a fuel tank for a vehicle is disclosed. The vehicle comprises a frame and an engine. The frame supports at least a front wheel, at least a rear wheel, and at least a handlebar. The engine is supported by the frame, and drives the at least one rear wheel. The fuel tank has an inner member and an outer member. The inner member and the outer member are fixedly joined to one another to form a fuel storing space. The fuel tank is supported by the frame at a forward portion of the vehicle above the engine. A heat shield member is attached to the inner member for protection of the fuel tank.
[0009] In an embodiment, the fuel tank has a left portion, a right portion and a central portion. The left portion, the right portion, and the central portion of the fuel tank extend forwardly along the frame from the frontmost part of a seat of the vehicle.
[00010] In an embodiment, a liquid can flow between the right portion, the left portion and the central portion at a rearmost point of the fuel tank.
[00011] In an embodiment, the heat shield member is attached to a portion towards a vehicle rear direction, at a rear end of the inner member.
[00012] In an embodiment, the heat shield member is attached to the inner member by one or more adhesive means.
[00013] In an embodiment, at least one canister is disposed between the inner member and a main frame member of the frame, the canister being connected to the fuel tank by at least one hose.
[00014] In an embodiment, the heat shield being located rearwards towards a vehicle rear direction of the at least one canister.
[00015] In an embodiment, one or more fuel hoses are connected between the fuel tank and the engine.
[00016] In an embodiment, the heat shield has a thickness less than 1 millimeter.
[00017] In an embodiment, the heat shield is an aluminium sheet.

Brief Description of Drawings
[00018] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
[00019] Figure 1 is an exemplary illustration of a two wheeled saddle type vehicle from a left side view of the vehicle.
[00020] Figure 2 is an exemplary illustration of a frame structure, the engine, and the fuel tank of the saddle type two wheeled vehicle from a left side view of the vehicle.
[00021] Figure 3 is an exemplary illustration of the fuel tank of the two wheeled saddle type vehicle from a top view of the fuel tank.
[00022] Figure 4 is an exemplary illustration of the fuel tank of the two wheeled saddle type vehicle without the heat shield from a bottom view of the fuel tank.
[00023] Figure 5 is another exemplary illustration of the fuel tank of the two wheeled saddle type vehicle with the heat shield from a bottom view of the fuel tank.
 
Detailed Description
[00024] Various features and embodiments of the present invention here will be discernible from the following description thereof, set out hereunder.
[00025] Figure 1 is an exemplary illustration of a two wheeled saddle type vehicle 100 from a left side view of the vehicle 100. The vehicle 100 comprises a frame structure, an engine 103, a handlebar 106, a front wheel 104, a rear wheel 105, a fuel tank 101, and a seat assembly 102. The front wheel 104 can be used to steer the vehicle 100, while the engine 103 drives the rear wheel 105, which propels the vehicle 100 forward. In this exemplary illustration, the engine 103 is shown to be connected to the rear wheel 105 using a chain drive system. Other possibilities include a belt drive system or a shaft drive system. The rear wheel 105 is generally mounted to the vehicle 100 using a swingarm which is connected to the vehicle 100 frame through a rear suspension assembly. The frame includes a headtube. The handlebar 106 is connected to the front wheel 104 through the headtube and a front suspension assembly. The handlebar 106 is further configured to support the front lamp assembly, including the primary lamp and the turn signal lamps. The frame further includes a down frame member 107, a main frame member 108, and a rear frame member 109. The main frame member 108 extends rearwards from the headtube, and then extends downwards. The down frame member 107 of the frame extends downwards from the headtube, and then extends rearwards, to meet the main frame member 108 at its rearmost point. The rear frame member 109 extends rearwards from the main frame member 108, and supports the rear structure of the vehicle, including the seat assembly 102, rear tail lights and turn signal lamps, and the rear fender assembly of the vehicle 100. The vehicle 100 is configured such that the engine 103 is supported by the frame, such that it is disposed below the main frame member 108, and above the down frame member 107, and mounted at a plurality of mounting points to secure the engine 103 to the frame of the vehicle 100. The fuel tank 101 is disposed above the engine 103, and the seat assembly 102 is disposed rearwards of the fuel tank 101. The fuel tank 101 is configured to be disposed on the main frame member 108, such that it extends downwards on the left hand side and the right hand side of the vehicle 100 from the portion of the fuel tank 101 that is directly mounted on the main frame member. The fuel tank 101 therefore covers the main frame member 108 from three sides, except the bottom, where the engine 103 is disposed. The vehicle 100 further includes style and fairing parts which have functional and aesthetic purposes.
[00026] Figure 2 is an exemplary illustration of a frame structure, the engine 103, and the fuel tank 101 of the saddle type two wheeled vehicle 100 from a left side view of the vehicle 100. The frame consists of a headtube, a main frame member 108 which extends rearwards from the headtube and then downwards, a down frame member 107 which extends downwards from the headtube and then rearwards. The engine 103 is disposed between the main frame member 108 and the down frame member 107. The engine 103 is also disposed below the fuel tank 101. The engine 103 consists of two parts, a main body 103a, and a cylinderhead 103b. the main body 103a of the engine 103 houses the crankshaft and the transmission assembly of the saddle type vehicle 100. The cylinderhead 103b functions as the combustion chamber for the fuel being burned in the engine 103. A piston functionally connected to the crankshaft is disposed in the cylinderhead 103b. The fuel from the fuel tank is combusted when the piston is nearing a top dead centre position so that the combustion happens under maximum pressure, pushing the piston towards its bottom dead centre position, which is translated into rotational motion of the crankshaft. Not all of the energy generated by the combustion is translated into rotational motion. Some of the energy is lost in the form of heat. The heat is transmitted from the engine 103 into the atmosphere. In the present embodiment, to facilitate quicker dissipation of heat, the cylinderhead 103b is configured with a plurality of fins so that the engine 103 can be cooled by the air flowing over the fins when the vehicle 100 is in motion. The fuel tank 101 being directly above the engine 103 is susceptible to the heat generated by the engine 103. The fuel tank is made of two metallic members, an inner member and an outer member. The inner member and the outer member of the fuel tank 101 are fixedly joined together to form the fuel tank 101. The inner member is disposed inwards towards the main frame member 108, while the outer member is disposed outwards. The attachment means for mounting the fuel tank 101 on the main frame member 108 are provided on the inner member. The rear frame member 109 extend rearwards and upwards from the main frame member 108. The rear frame member 109 supports the mounting of the seat assembly 102, the rear fender assembly, and the tail lamp assembly. The seats 102 are usually mounted on the rear frame 109 by using side rails. In many two wheeled saddle type vehicles, the engine is a load bearing part, and as such the assembly of the down frame member 107 and the main frame member 108 would also consist of the engine 103. In the present embodiment however, the engine 103 is structurally supported by the vehicle 100 frame assembly. Fuel may be injected into the engine 103 from the fuel tank 101 using a fuel injection system, or fed into the engine 103 using a carburettor.
[00027] Figure 3 is an exemplary illustration of the fuel tank 101 of the two wheeled saddle type vehicle 100 from a top view of the fuel tank 101. The fuel tank 101 has three sections, a central portion (between the axis R-R’ and L-L’), a right portion (rightward of the axis R-R’), and a left portion (leftward of the axis L-L’). The fuel tank 101 is configured with a fuel filler cap 110. The fuel filler cap 110 is configured to be opened so that fresh fuel can be pumped into the fuel tank 101. The fuel filler cap 110 is also configured to prevent any fuel vapour from escaping the fuel tank 101. The rearmost point 101a of the fuel tank 101 acts as a conduit for the fuel between the left portion, the right portion and the central portion of the fuel tank 101. A fuel tank mounting point 101b is configured at the end, so that the fuel tank 101 can be securely mounted on the main frame member 108. The central portion rests on the main frame member 108. The right portion extends downwards from the central portion on the right hand side of the vehicle 100, and the left portion extends downwards from the central portion on the left hand side of the vehicle 100.
[00028] Figure 4 is an exemplary illustration of the fuel tank 101 of the two wheeled saddle type vehicle 100 without the heat shield 101d from a bottom view of the fuel tank 101. The underside 101c of the fuel tank 101 can be seen in this figure. The underside 101c is configured to conform to the packaging requirements of the various parts of the vehicle 100 that are disposed under the fuel tank 101. The fuel tank 101 consists of a fuel pump 111. The fuel pump 111 is configured to pump fuel to the fuel injector in the engine 103 assembly. One or more hoses 112 are connected to the fuel pump 111 that are fed to the engine 103. The fuel tank 101 also comprises a canister 113, which is configured to capture fuel vapours escaping from the fuel tank 101, and feed them into the engine 103 assembly for combustion. The central portion (between the axis R-R’ and L-L’) of the fuel tank 101 is configured with one or more mounting means 114. These mounting means 114 are configured to secure the fuel tank 101 to the main frame member 108 at a forward end of the vehicle 100. At the rear, the fuel tank is mounted to the main frame 108 by the fuel tank mounting point 101b. generally, for easier assembly of the fuel tank, the mounting means are slidable attachment means that do not require fastening, whereas the fuel tank 101 is mounted to the main frame 108 at the mounting point 101b using fasteners. The underside 101c of the fuel tank 101 is usually painted or lined with a corrosion resistant material in order to protect the structural integrity of the fuel tank 101. A further fuel flow regulator may also be provided as part of the fuel system of the vehicle 100.
[00029] Figure 5 is another exemplary illustration of the fuel tank 101 of the two wheeled saddle type vehicle 100 with the heat shield 101d from a bottom view of the fuel tank 101. The underside 101c of the fuel tank 101is the part which is most susceptible to the heat dissipated from the engine 103. Since the rider of the vehicle 100 sitting on the seat 102 will have a portion of his / her lower body in proximity of the fuel tank 101, it can cause discomfort to the rider. Therefore, a heat shield 1101d is provided at the rear end of the underside 101c as shown. The heat shield 101d is configured to conform to the shape of the underside 101c of the fuel tank 101. According to an embodiment of the present invention, the heat shield 101d is an aluminium sheet. As per another embodiment, the heat shield 101d is fixedly attached to the underside 101c with adhesive means. In a further embodiment, the heat shield has a thickness less than 1 millimetre. Providing the heat shield 101d at the rear end of the underside 101c prevents transmission of heat from the engine 103 to the rider’s lower body, especially his / her thighs and knees.
[00030] The present subject matter provides various advantages. The heat shield 101d has a very low weight, and therefore does not affect the performance of the vehicle. Since the heat shield 101d is attached to the underside 101c of the fuel tank 101 by adhesive means, the assembly of the heat shield 101d is a simple process. Attaching the heat shield does not require any changes in design of the vehicle 100 or the fuel tank 101. Further, the heat shield 101d provides adequate protection to the rider that he / she does not feel discomfort.
 
List of reference signs:
100 – saddle type vehicle
101 – fuel tank
101a – rearmost point of the fuel tank
101b – fuel tank mounting point
101c – underside / inner member of the fuel tank
101d – heat shield
102 – seat assembly
103 – engine
103a – main body of the engine
103b – cylinderhead of the engine
104 – front wheel
105 – rear wheel
106 – handlebar
107 – down frame member
108 – main frame member
109 – rear frame member
110 – fuel filler cap
111 – fuel pump
112 – one or more hoses
113 – at least one canister
114 – one or more mounting means
L-L’ – reference axis separating the left portion from the central portion
R-R’ – reference axis separating the right portion from the central portion
, Claims:We claim:
1. A fuel tank (101) for a vehicle (100), the vehicle (100) comprising
a frame, the frame supporting at least a front wheel (104), at least a rear wheel (105), and at least a handlebar (106),
an engine (103), the engine (103) being supported by the frame, and driving the at least one rear wheel (105),
wherein
the fuel tank (101) having an inner member and an outer member, the inner member and the outer member being fixedly joined to one another to form a fuel storing space,
the fuel tank (101) being supported by the frame at a forward portion of the vehicle (100) above the engine (103),
a heat shield member (101d) being attached to the inner member for protection of the fuel tank (101).
2. The fuel tank (101) as claimed in claim 1, wherein the fuel tank (101) having a left portion, a right portion and a central portion, the left portion, the right portion and the central portion of the fuel tank (101) extend forwardly along the frame (108) from the frontmost part of a seat (102) of the vehicle.
3. The fuel tank (101) as claimed in claim 2, wherein a liquid can flow between the right portion, the left portion and the central portion at a rearmost point (101a) of the fuel tank (101).
4. The fuel tank (101) as claimed in claim 1, wherein the heat shield member (101d) being attached to a portion towards a vehicle (100) rear direction, at a rear end of the inner member (101c).
5. The fuel tank (101) as claimed in claim 4, wherein the heat shield member (101d) being attached to the inner member (101c) by one or more adhesive means.
6. The fuel tank (101) as claimed in claim 1, wherein at least one canister (113) being disposed between the inner member (101c) and a main frame member (108) of the frame, the canister (113) being connected to the fuel tank (101) by at least one hose.
7. The fuel tank (101) as claimed in claim 6, wherein the heat shield (101d) being located rearwards towards a vehicle (100) rear direction of the at least one canister (113).
8. The fuel tank (101) as claimed in claim 1, wherein one or more fuel hoses (112) being connected between the fuel tank (101) and the engine (103).
9. The fuel tank (101) as claimed in claim 1, wherein the heat shield (101d) has a thickness less than 1 millimeter.
10. The fuel tank (101) as claimed in claim 1, wherein the heat shield (101d) is an aluminium sheet.