This invention relates to fuel supply systems, for example, for dual fuelled vehicles.
As petrol prices go up, an urgent need has arisen for alternative fuels as fuel conservation efforts have accelerated. Gas fuelling of vehicles, particularly cars, has become more popular with this trend. Such gas fuelling may follow conversion or retro-fitting of a gas fuel system to a vehicle. However, while gas fuels may be usefully employed, there remains a need to run vehicles with a liquid fuel, typically petrol, in many cases. That is, gas fuel stations from which gas fuel may be replenished are still to become widespread. A dual fuel strategy is therefore prudent and multiple fuel tanks are required with gas fuels being selected as the primary fuel in most cases. In this way, fuel may be made available according to regional requirements without affecting the performance or efficiency of the vehicle. As the infrastructure for gaseous fuel supply improves, the need for a second fuel tank may be reduced although there may continue to be a preference to retain such a facility in order to provide engine startability or other benefits to the vehicle owner.
As to preferred gaseous fuels, liquefied petroleum gas (LPG) is a byproduct from oil production and forms a liquid when pressurized for storage as fuel. It is a useful fuel to be used in vehicles for various reasons. Minimum carbon monoxide, carbon dioxide and hydrocarbons are emitted when LPG is used as fuel. LPG combustion is smoother than petrol because of inherent high octane rating. It enters the engine as a gas and burns more efficiently and quickly resulting in a quieter and smoother engine.
A converted vehicle generally can run on either petrol or LPG. Generally a vehicle's engine starts on petrol and then switches on to LPG by the system electronics if so designed. Otherwise, a manual switch can also work as changeover switch. A switch installed in a position accessible to the rider/ driver can be used to alternate between fuels even when the vehicle is in motion, if so designed. This transfer between the fuel types can be made so as to minimise any drivability issues for the operator.
Compressed Natural Gas (CNG) and LPG can be used in a spark ignited internal combustion engine without making any substantial modifications to the engine. However, a gas conversion kit needs to be retrofitted in the vehicle for safe handling of the gas and to supply the gas to the carburetor helping the engine to run either with petrol or CNG/LPG. Merely by having a changeover switch, it is possible to switch supply fuel i.e., petrol or the gas to the engine.
Conventionally, the two fuel tanks are spaced apart for manufacturing or packaging convenience. That is, space constraints on vehicles have previously required such spacing. The fuel tanks are not placed proximally in the vehicle. For example, it may be necessary to locate the LPG tank remotely from the petrol tank (which is normally located just forward of the seat of a motorcycle) in a position such as the luggage box or even a sidecar of a motorcycle. Such spacing apart of the tanks creates inconvenience for the vehicle operator or motorcycle rider in that, on refueling, the operator must maneuver the vehicle to access the fuel filler points fixed in different zones of the vehicle. This wastes time and makes dual fuelled vehicles less desirable to operate. In addition, more significant adverse impacts such as loss of vehicle stability, decreased fuel efficiency and increased manufacturing costs due to need for extended fuel supply piping systems may result. These sorts of adverse impacts may arise even in the case of a mono gas fuelled vehicle.
Accordingly, an object of the invention is to provide a fuel supply for a vehicle which avoids at least some of these inconveniences.
Another or alternative object, of the invention is to provide a gaseous fuel supply for a vehicle which is conveniently located and packaged within the vehicle.
With these objects in view, the present invention provides a fuel supply system for a vehicle comprising:
a first tank for a first fuel; and a second tank for a second fuel
wherein said tanks are located proximal to each other in the system and when deployed in a vehicle.
These tanks may be co-located in the system and, when deployed, in the same portion of a vehicle such as a two wheel vehicle, for example a motorcycle. That is, the tanks may be arranged on a vehicle, during manufacture, such that a typical vehicle operator will find the tanks proximal, being able to access both tanks for filling with fuel and maintenance advantageously without changing position of himself/or the vehicle. Ideally, the operator may - due to the co-location of the tanks- be capable of filling the tanks without moving from a seated position during the filling operation. Advantageously, when the fuel supply system is deployed in a vehicle, the filler points of first and second tanks are co-located or arranged within arms length of the operator either when seated or when the vehicle is placed for a refueling operation. The first and second tanks may be co-located within a holder. Such an arrangement of fuel tanks within the holder makes accessibility of filling points for each fuel tank easier for the vehicle operator.
The first tank may hold a primary fuel, that is, the fuel on which operation of the vehicle is desired, typically, to occur. The second tank will then hold the secondary fuel. Gaseous fuels are becoming highly advantageous and the first tank may hold a gaseous fuel and the second tank a liquid fuel, such as petrol, to be used in case gas supplies are unavailable. In such case, the first tank is a pressure vessel conveniently, of cylindrical or ellipsoid shape, meeting the standards for containers of fuel gases. However, the second tank may have a non-regular shape. The first tank would typically be made of thicker or heavier gauge material than the second tank for petrol or other liquid fuel.
A vehicle frame portion or frame member(s) of the vehicle, such as main tube(s) of a motorcycle, may be designed to provide a mounting structure to accommodate both the fuel tanks or the holder for the fuel tanks. Mounting means, such as brackets, may be provided on the main tube(s) to secure the tanks within the holder to prevent excessive vibration during vehicle motion. The shape and structure of the main tubes, the inner shape and contour of the holder and the arrangement of the tanks may be arranged to optimize the use of space in the holder, advantageously minimizing it, or put another way, using all the available space within the holder. The shape of the tank for the first fuel may be dictated by the shape of the second tank and vice versa. The shape of the first tank may also be dictated by the physical properties of the pressurized gaseous fuel. The capacity of the second tank may be dictated by both the capacity of the holder and the capacity of the first tank and vice versa. In the case of motorcycles, the holder may have comparable capacity, and similar look, to petrol tanks currently used in motorcycles. In this way, the dual fuel tanks of the present invention can be employed without changing the aesthetics of motorcycle design. This facilitates retro-fitting and appeals to the customer. More specifically, the fuel tank holder may be formed in a fuel tank body, of conventional aesthetic appearance, mounted between the handlebar and the rider seat, above the engine.
The first tank could fit with or to the second tank; that is, the second tank could be assembled together with the first tank. The tanks could couple together in a neat or other fit. The second tank could also be formed within a body of the first tank. The second tank could be defined by a wall of the first tank. The second tank could be accommodated within wall(s) of the first tank. With the tanks mounted in a fuel tank body, as above described, they are accommodated with economical use of space not being externally visible during riding. This allows vehicle stability to also be enhanced over vehicles using prior art dual fuel supply systems. Where a luggage box location for the fuel tank may have been otherwise utilised, there is also the potential for increased luggage capacity adopting the dual fuel supply system as above described.
In the case that the first tank is a pressurized tank adapted to contain a gaseous fuel, such as LPG or CNG, the pressures within the tank (and various tank manufacturing regulations) dictate that the tank be of a generally cylindrical configuration. This creates limitations as to the tank's design. However, the second fuel tank may be conveniently shaped so as to conform to shape of the first tank and to the inner shape of the holder - that is the second tank takes up the space available between the first tank and the holder, thereby optimizing space efficiency and packaging.
The fuel supply system may be adopted within the vehicle during initial manufacture or later retrofit. It may be sold separately from the vehicle as an assembly or component parts with assembly manual. The fuel supply system also allows flexibility at the point of manufacture since the manufacturer may select dual fuel supply systems or mono fuel supply systems to be accommodated within existing fuel tank bodies depending on the buyer demand for each system. Fuel supply piping may also be supplied in accordance with the selected fuel supply system in kit or other form.
Provision may readily be made for changeover of fuels. That is, manual or automatic changeover may be provided for. In the case of a manual changeover, a switch may be provided at a convenient location for the operator. In the case of a motorcycle or similar vehicle, the changeover switch may be mounted on the handlebar and operable from a normal riding position. The changeover switch may be operable without moving the hands from the handlebar grip.
The fuel supply of the invention allows a vehicle operator, such as a motorcycle rider, to fill the tank of choice and use the choice of fuel for operating the vehicle while remaining seated without any need to either dismount from the seat or to turn the vehicle in a different direction.
The fuel supply system of the invention may be applied to a range of vehicle types. In this aspect, there may be provided a two wheel vehicle comprising a fuel supply system comprising a gaseous fuel tank and a liquid fuel tank, and a vehicle frame portion for mounting a holder in which said tanks are located wherein the gaseous fuel tank and the liquid fuel tank are co-located within said holder between the handlebars and the rider seat of the said two wheel vehicle.
Gaseous fuel need not be the primary fuel and the mode of operation of the engine is not dictated by the nature of the fuel supply system.
In another aspect, the present invention provides a two wheel vehicle with a gaseous supply system having a gaseous fuel tank accommodated within a holder mounted between the handlebars of the vehicle and the rider seat. The holder may be of the same appearance as a conventional petrol tank holder for a motorcycle maintaining current aesthetics of motorcycle design. Alternatively, the holder may be covered with a covering to resemble a conventional petrol tank. A vehicle frame portion or frame member(s), such as main tube(s) of a motorcycle frame, may be fabricated and configured to mount the holder or fuel tank.
The fuel tank may be circular cylinder shaped or ellipsoidal cylinder shaped, with the wide access of the ellipsoid being transverse to the vehicle. The single gas tank construction may require strengthening of the front portion of the frame, or main tube(s), to support the tank in comparison to the conventional petrol tank arrangement. That is because gas tanks need to be of a heavier gauge material than petrol tanks and also because of the required size and shape of the tank prevents a frame member of the vehicle chassis passing through the area where the tank is located (as can be distinguished from a conventional petrol tank which can have a shape adapted to straddle chassis members of the vehicle, or created to have suitable indentations for chassis members to pass through).
The other main advantages of the fuel supply system and vehicle of the invention will become apparent from the following description and illustrated drawings accompanying the description.
DESCRIPTION OF DRAWINGS:
The fuel supply system and vehicle of the invention may be more fully understood from the following description of a preferred embodiment thereof made with reference to the accompanying drawings in which:
Figure 1 is a side view of a two wheel vehicle being a four stroke motorcycle and incorporating a prior art dual fuel supply system.
Figure 2 illustrates construction of fuel tank and main tube of a motorcycle according to a prior art embodiment.
Figure 3 is a rear view of the motorcycle shown in Figure 1.
Figure 4 is a side view of a two wheel vehicle being a four stroke motorcycle and incorporating the dual fuel supply system of one embodiment of the present invention.
Figure 5 is a top view of the motorcycle shown in Figure 4.
Figure 6 illustrates a construction for the fuel tank and main tube of a motorcycle according to a further embodiment of the invention.
Referring to Figures 1, 2 and 3, there is shown a motorcycle 10 having a spark ignited engine operating on the four stroke cycle and gas powered by liquefied petroleum gas (LPG) fuel. Motorcycle 10 comprises a luggage carrier 1, at the rear, which accommodates an LPG tank 3. Its side location, an inconvenient location, may be noted. A petrol tank 4 having filling point covered by petrol cap 4b is accommodated within a conventional fuel tank body 40 away from LPG tank 3. Petrol is used as a secondary fuel to be used in case LPG runs out in areas where refueling may be difficult. The bottom surface of the fuel tank body 40 is so shaped to accommodate the main tube 5 of motorcycle 10. The remoteness of the petrol and gas tanks from each other disadvantageously causes a reduction in available luggage space in luggage carrier 1. In addition, the motorcycle rider must maneuver the motorcycle 10 through two positions to fill the LPG and petrol tanks 3 and 4 during a refueling operation.
Referring now to Figures 4, 5 and 6, the motorcycle 10 again is provided with LPG and petrol tanks. However, in this case, the two tanks, LPG tank 11 and petrol tank 16, are arranged proximal to each other, being co-located and having co-located fuel filling points 15 and 22. It will be noted that both tanks 11 and 16 are arranged within a fuel tank holder 27, located in a front portion of the motorcycle 10 located between the handlebars 28 and the rider seat 29, again of conventional external shape for a motorcycle fuel tank and so are not visible during riding. A vehicle frame portion comprising two main tubes 20 and 21 of the motorcycle frame are conveniently shaped as shown in Figure 6 to accommodate both the fuel tanks 11 and 16 with the bottom surface of the fuel tank holder 27 shaped appropriately without affecting the external aesthetic appearance of the fuel tank holder 27. Main tubes 20 and 21 are
s
also designed to be of sufficient strength to bear the weight of the LPG tank 11 and petrol tank 16 co-located within fuel tank holder 27. The LPG tank 11, of ellipsoid cylindrical appearance, is constructed, in accordance with pressure vessel standards, of an appropriately gauged metal or metal alloy. Remaining space within the fuel tank holder 27 is sufficient to accommodate the petrol tank 16, which may be of plastic. The LPG fuel system is otherwise conventional including regulator 12, multi valve assembly 13, gas filler assembly 14 and piping to connect these components.
The LPG and petrol tanks 11 and 16 are mounted within common fuel tank holder 27 by suitable brackets 19 and 26 provided at the rear and the front ends of a vehicle frame portion formed by the main tube(s) 20 and 21 respectively, that bracket support 19 for the LPG tank 11 taking the form of a cradle. Ready replacement and filling of the tanks 11 and 16 may be achieved without maneuvering of the motorcycle 10 during the refueling operation. In addition, luggage capacity is not compromised and the cost of fuel supply piping is potentially reduced over the motorcycle 10 of Figures 1 and 2. Such advantages may be achieved by retrofitting the motorcycle 10 of Figures 1 and 2 with the dual fuel supply system as above described.
It will be observed from Figure 5 and 5a that the tanks 11 and 16 are arranged with their axes 32 and 33 arranged parallel to the vehicle longitudinal axis 31. Tanks 11 and 16 are also disposed about the vehicle longitudinal axis 31 to provide balancing of their masses. The arrangement of the tanks 11 and 16 provides both static and dynamic balancing of tank 11 and 16 masses to the vehicle as the center of gravity of these tanks is arranged close to the longitudinal axis 31 of the vehicle thereby achieving static and dynamic balancing.
Also to be noted is a changeover or selector switch 25 mounted on the handlebar to switch between LPG and petrol at the option of the motorcycle rider. LPG operation is preferred where supplies are available. Indicator 23 provides information as to the fuel being used and remaining supplies.
It is to be understood that the specific embodiment shown in the drawings and described in detail herein is merely illustrative of the principles of the present invention. Various modifications and changes may be implemented by those skilled in the art and such modifications and changes are within the scope of this invention.

' WE CLAIM:
1. A fuel supply system for a vehicle comprising a first tank for a first fuel; and a second tank for a second fuel wherein said tanks are located proximal to each other in said system and when deployed in a vehicle.
2. A fuel supply system as claimed in claim 1 wherein the first tank and the second tank are co-located.
3. A fuel supply system as claimed in any one of the preceding claims wherein the first and second fuel tanks are co-located in a holder.
4. A fuel supply system as claimed in any one of claims 1 to 3 wherein the first tank carries a gaseous fuel.
5. A fuel supply system as claimed in claim 1 or 2 wherein the second tank carries a liquid fuel.
6. A fuel supply system as claimed in any one of the preceding claims wherein the holder has an external shape resembling a conventional two wheeler fuel tank,
7. A fuel supply system as claimed in claim 4 wherein the first fuel tank has a cylindrical or ellipsoid shape and said second fuel tank has a non-regular shape.
8. A fuel supply system as claimed in any one of the preceding claims wherein, when the fuel supply system is deployed within a vehicle, filler points of said first and second tanks are co-located or arranged within arms length of a vehicle operator either when seated or when the vehicle is placed for a refueling operation.
9. A fuel supply system as claimed in any one of the preceding claims wherein one fuel tank is located inside the other fuel tank.
10. A fuel supply system as claimed in any one of the preceding claims wherein the fuel tanks are arranged with their axes parallel to the vehicle longitudinal axis.
11 .A fuel supply system as claimed in claim 10 wherein the fuel tanks are arranged to provide static and dynamic balancing of mass to the vehicle.
12. A two wheel vehicle having a fuel supply system as claimed in any one of Claims 1 to 11.
13. A two wheel vehicle comprising a fuel supply system having a gaseous fuel tank, a liquid fuel tank wherein the fuel tanks are co-located between the handlebars and the rider seat of the said two wheel vehicle.
14. A two wheel vehicle as claimed in claim 13 further comprising a vehicle frame portion for mounting a holder wherein the fuel tanks are located in the said holder.
15. A two wheel vehicle as claimed in claim 13 and 14 wherein the holder has an external shape resembling the shape of a conventional two wheeler fuel tank.
16. A two wheel vehicle as claimed in claim 13 to 15 wherein a filling point is provided for the gaseous fuel tank within arms length of a vehicle operator when seated on the vehicle.
17. A two wheel vehicle as claimed in any one of claims 13 to 16 wherein a filling point for the liquid fuel tank is co-located with the filling point of the gaseous fuel tank.
18. A two wheel vehicle as claimed in any one of claims 13 to 17 wherein the gaseous fuel tank is a pressure vessel of heavier gauge material than the material of the petrol tank.
19. A two wheel vehicle as claimed in any one of claims 13 to 18 wherein the shape and structure of the vehicle frame portion, the inner shape and contour of the
holder and the arrangement of the tanks is selected to optimize the use of space in the holder.
20. A two wheel vehicle as claimed in claim 19 wherein the shape and structure of the frame, the inner shape and contour of the holder and the arrangement of the tanks is selected to minimise use of space in the holder.
21. A two wheel vehicle as claimed in any one of claims 13 to 20 wherein one fuel tank is located inside the other fuel tank.
22. A two wheel vehicle as claimed in any of claims 13 to 21 where the fuel tanks are arranged with their axes parallel to vehicle longitudinal axis.
23. A two wheel vehicle as claimed in claim 22 where the gaseous fuel tank is arranged with its axis along or in the vehicle's vertical midplane.
24. A two wheel vehicle comprising a gaseous fuel supply system having a gaseous fuel tank wherein the fuel tank is mounted between the handlebars and the rider seat of the vehicle.
25. A two wheel vehicle as claimed in claim 24 further comprising a vehicle frame portion for mounting a holder wherein the fuel tank is mounted in the said holder.
26. A two wheel vehicle as claimed in claims 24 to 25 wherein a filling point is provided for the gaseous fuel tank within arms length of a vehicle operator when seated on the vehicle.
27. A two wheel vehicle as claimed in claims 24 to 26 wherein the holder is of the same appearance as a conventional petrol tank holder for a motorcycle.
28. A two wheel vehicle as claimed in claims 24 to 27 where the fuel tank is arranged with its axes parallel to vehicle longitudinal axis.
29. A two wheel vehicle as claimed in claims 24 to 27 where the fuel tank is arranged with its axis along or in the vehicle's vertical midplane.
30. A two wheel vehicle having a fuel supply system as claimed in any one of Claims 1 to 11, wherein the first and second fuel tanks are arranged between the handlebars and the rider seat of the said two wheel vehicle.
31. A three wheel vehicle having a fuel supply system as claimed in any one of Claims 1 to 11, wherein the first and second fuel tanks are arranged between the handlebars and the rider seat of the said three wheel vehicle.
32. A fuel supply system substantially as hereinbefore described with reference to Figures 4 to 6.
33. A two wheel vehicle substantially as hereinbefore described with reference to Figures 4 to 6.