Field of Invention

The present invention relates to a modified fuel tank for use in two wheelers such as those that are designed to run on natural gas (CNG) as well as conventional fuel i.e. Gasoline. Background

Natural gas is a low cost fossil fuel substitute to conventional fuels such as gasoline and diesel. Though combustion of natural gas produces greenhouse gases, the amount of greenhouse gas produced is comparatively lesser than that produced by the combustion of an equivalent amount of fossil fuel like gasoline or diesel. Natural gas therefore is environmentally cleaner and cheaper than conventional fuel. Due to the relative ease of retrofitting existing gasoline vehicles and due to the cheaper cost of operating a natural gas vehicle over a gasoline type vehicle, many fleet operators have converted their fleet of vehicles from gasoline to natural gas. This has led to an increase in its use in vehicles and in many cases, even promoted by local government bodies in order to reduce vehicular pollution levels. One problem in converting an existing gasoline vehicle to a natural gas vehicle is the mounting of the compressed natural gas cylinder to the vehicle. Hence not all vehicles can be practically adapted to run on natural gas. Natural gas takes up comparatively more space for each gasoline equivalent unit and has to be stored under highly pressurized containers. As a result, natural gas tanks require more space to hold the same amount of gasoline equivalent fuel. Generally, a vehicle adapted to run on natural gas comprises a pressurized tank placed in the trunk of the vehicle where

l additional space is readily available. Since two wheelers do not have a trunk and the space available on a two wheelers is already limited, it becomes practically impossible to adapt a two wheeler for use with natural gas.

Another important consideration for a vehicle owner who intends to adapt his vehicle to run on compressed natural gas is the vehicle's ability to run on gasoline fuel in the event compressed natural gas is used up. Compressed natural gas for vehicle use is not easily available in many parts of the country and this forces the vehicle owners to operate their motor vehicle using the more readily available gasoline fuel until compressed natural gas is available for a refill. Thus it is important to have provisions for storage of gasoline fuel in a vehicle which is being adapted to run on compressed natural gas. This presents an additional challenge for practically adapting a two wheeler vehicle for use with natural gas owing to the space limitation.

Attempts have been made to adapt a two wheeler to run on natural gas such as the one described in WO201 1 129835, teachings of which are incorporated herein by reference. The invention describes a natural gas container mounted onto a two wheeler chassis, in place of a conventional fuel tank. The invention can be adapted to retrofit existing two wheelers but requires substantial modification of the basic two wheeler design. The present invention is designed to alleviate the above problems faced with the use of natural gas in vehicles.

Summary of the Invention The present invention relates to a two wheeler vehicle such as a motorcycle adapted to run on compressed natural gas. More particularly, the present invention provides a modified fuel tank which can be mounted in place of a conventional fuel tank on a motorcycle, said modified fuel tank comprising of cavities on the underside to accommodate gas containers containing compressed natural gas. The modified fuel tank of the present invention comprises of a curved undersurface having a fuel reservoir centrally located on the said curved undersurface of the fuel tank. The fuel reservoir extends along the longitudinal axis of the fuel tank such that a cavity is formed on either side of the fuel reservoir defined by the walls of the fuel reservoir and the undersurface of the fuel tank. In an embodiment of the invention, the said cavity formed has a shape complementary to that of an elongated cylinder. The modified fuel tank of the present invention has an advantage over the conventional fuel tank in that, it allows storage of conventional gasoline fuel and provides space for accommodating elongated cylindrical shaped containers for storage of compressed natural gas.

The present invention further provides a two wheeler motor vehicle which uses compressed natural gas as fuel, said two wheeler vehicle having a supporting bracket assembly comprising of support brackets attached to the two wheeler vehicle chassis, the brackets having free ends and a locking mechanism to secure the free ends together in a closed loop around a cylindrical object such as a gas container.

In one embodiment, the present invention comprises of a motorcycle with atleast two gas containers mounted in place of a conventional fuel tank, said gas containers held in place with brackets and the modified fuel tank placed above the gas containers such that each of the said gas container resides in the cavities formed under the modified fuel tank. The modified fuel tank of the present invention has an external appearance which resembles the primary or the convention fuel tank of the motor vehicle and can be easily installed after removing the conventional fuel tank of the motor vehicle without affecting the structure or profile of the motor vehicle. The invention provides a convenient way to adapt or retrofit existing and new motor vehicles with the ability to store natural gas without altering or modifying the motor vehicle in a substantial manner. The center of gravity, weight balance and symmetry of the vehicle is preserved to provide a safe and unaltered riding experience.

Brief Description of the Drawings

The present invention is illustrated by way of examples in the following drawings:

Fig 1 shows a prospective view of the modified fuel tank taken from the top, back and side of the fuel tank.

Fig 2 shows a prospective view of the modified fuel tank from the front. Fig 3 show a bottom view of the modified fuel tank along with a cross section view.

Fig 4 shows the construction and the design of the bracket which is used to hold gas containers in place on the motor vehicle chassis.

Fig 5 shows a top view of the motorcycle with gas container mounted in place of a conventional fuel tank on the motor cycle.

Fig 6 shows a top view of the motorcycle with the modified fuel tank place above the gas containers.

Brief Description of the Invention

One embodiment of the present invention relates to a modified fuel tank for use in a two wheeler motor vehicle, more particularly a motorcycle, which is indicated in Fig 1 , Fig 2 and Fig 3. The modified fuel tank (5) comprises of an outer surface (10) and a curved undersurface (11). A fuel reservoir (12) is provided on the curved undersurface (11) for storing gasoline based fuel. A cavity (13) and (14) is formed on either side of the fuel reservoir which is defined by the side walls ( 5) and (16) of the fuel reservoir (12) and walls of the undersurface (11) of the modified fuel tank. In the present embodiment, the cavity (13) and (14) has a shape complimentary to that of an elongated cylinder. A coverable opening (18) is provided on the outer surface (10) of the modified fuel tank which is in communication with the fuel reservoir (12). The coverable opening (18) allows one to dispense conventional gasoline based fuel into the fuel reservoir (12).

Referring to Fig. 3 there is illustrated the undersurface of the modified fuel tank (5). The fuel reservoir (12) extends along the central longitudinal axis of the modified fuel tank (5) with cavities (13) and (14) forming on either side of the fuel reservoir (12). The fuel reservoir (12) comprises of a fuel discharge hole (19) located at the rear end which is operably connected to the motor vehicle's engine using conduits and feeds conventional gasoline based fuel into the motor vehicle engine. The modified fuel tank further comprises of an attachment point (17) using which it is securely affixed to the motor vehicle chassis.

Another embodiment of the present invention provides for a two wheeler motor, vehicle for use with compressed natural gas said motor vehicle having gas containers mounted in place of a conventional fuel tank. The gas containers are held in place with the help of a plurality of brackets attached to the motor vehicle chassis using a nut and bolt assembly or any other securing means. The brackets are preferably constructed of sheet metal bent into a configuration to allows the brackets to loop around a cylindrical object such as the gas containers. Gaskets or liners may be utilized between brackets and surface of the gas containers to reduce vibrations and noise. The free ends of the bracket are provided with mounting holes which align with each other, once the bracket is looped around gas containers, for receiving fasteners there through. Alternative, the free ends can be also fused welded together to hold the cylindrical gas containers firmly in place as, indicated in Fig (4). Fig (5) shows the top view of the two wheeler motor vehicle wherein the convention fuel tank has been removed from the front end of the motor vehicle chassis and gas containers (21) and (22) mounted on to the motor vehicle chassis. The gas containers (21) and (22) are placed in the curved portion of the brackets (23) and (24) with fasteners inserted through the holes of the free ends of the bracket to fix gas containers securely in place. It is important to note that brackets should be located as near to the end gas containers as is reasonably possible. Reference is made further made to Fig (6) which shows the motor vehicle with the modified fuel tank (5) in place covering the gas container (21) and (22). The cavities (13) and (14) (not seen in the figure) accommodate the gas container while the space between the gas containers is occupied by the fuel reservoir (12). In this manner, the modified fuel tank snugly fits onto the motor vehicle chassis without altering substantially the profile of the motor vehicle, but at the same time, providing storage for compressed natural gas and gasoline based fuel.

Since retrofit CNG kits for converting a gasoline fueled vehicle into a compressed natural gas vehicle are well known in the art and since the conversion kit or parts thereof are not part of the present invention, CNG kits are parts thereof will not be discussed or illustrated in detail herein. In any event, the assignee of the present invention, Officine Lovato Pvt. Ltd., has a natural gas vehicle conversion kit which includes two stages of regulation of the compressed natural gas, a mixture assembly to introduce natural gas into the vehicle engine, a dash mounted fuel gage and supporting electronics to interface with the OEM's computer onboard the vehicle. Officine Lovato Pvt. Ltd.'s gas system is a closed loop fuel control system which reduces tail pipe emissions, increases fuel economy and reduces engine wear. The components of the CNG conversion kit are accommodated in the chamber where the motor vehicle engine is mounted without any requirement for altering or modifying any further part or the profile of the motorcycle.

The invention described in the present invention thus provides a convenient way to store natural gas on a two wheeler motor vehicle without altering or modifying the structure or profile of the motor vehicle in a substantial manner. The center of gravity, weight balance and symmetry of the motor vehicle is preserved to provide a safe and unaltered riding experience. In the absence of availability of compressed natural gas and in order that the motor vehicle is able to run on conventional gasoline based fuel, the motor vehicle is provided with the fuel reservoir (12) which permits on the storage of conventional gasoline fuel. The driver can simply switch the operation of the motor vehicle on gasoline based fuel as and when required using an electronic switch provided as part of the CNG conversion kit.

The invention resides in the unique shape of the modified fuel tank and the arrangement of the said modified fuel tank (5) on the motor vehicle chassis along with the gas containers. It may be noted that a person skilled in the art of adapting a motor vehicle to run on compressed natural gas would be acquainted with different ways in which the gas containers and fuel reservoir (12) can be connected with the motor vehicle's engine so as to enable one to easily switch between gasoline and compressed natural gas to power the motor vehicle engine.

While the preferred embodiments of the present invention has been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as described hereinabove.