RELATED APPLICATION

Benefit is claimed to India Provisional Application No. 235/CHE/2011, titled "FUEL CONVERSION KIT FOR A MARINE VEHICLE" by SHYAMANUR, Sanjay, filed on 25th January 2011, which is herein incorporated in its entirety by reference for all purposes.

FIELD OF THE INVENTION
The present invention relates to the field of marine vehicles, and more particularly relates to an integrated portable liquefied petroleum gas (LPG) bunker cum fuel system for marine vehicles.

BACKGROUND OF THE INVENTION

For many years, marine vehicles are powered by marine outboard engines which use gasoline, kerosene, diesel or fuel oil and output harmful exhaust gases into the ocean. Pollution in water bodies such as lakes, rivers, seas, and oceans caused by engines running on kerosene, gasoline, diesel and fuel oil etc. is a major problem affecting the water bodies. Pollution in the water bodies directly affects ocean organisms and indirectly affects human health and resources. For example, toxic wastes are poisonous materials that harm many plants and animals in the ocean and have a huge impact on human being's health.

In order to reduce pollution in the water bodies, many efforts have been made to run the marine outboard engine on gaseous fuel such as liquid petroleum gas (LPG). Existing marine outboard engines are typically equipped with a fuel conversion kit which operates as an intermediate device for switching the marine outboard engine running on regular gasoline fuel to an alternate gaseous fuel like LPG.

However, existing fuel conversion kits have certain drawbacks which affect smooth operation of marine outboard engines. One of the major drawbacks is associated with freezing of fuel tanks which slows down vaporization of gaseous fuel when the marine vehicle is in motion. This may cause considerable amount of drop in power over a period of time of running and may eventually stop total fuel supply to the engine, resulting in toppling of the marine vehicle in the water. Also, the existing conversion kits may cause difficulty in starting the engine of the marine vehicle when an engine start is initiated after a gap of 30 minutes and may seize the engine. Also, the engine may be seized due to incomplete vaporization of fuel as well as entry of heavier refinery waste and dirt from the tank into the engine. Moreover, the use of existing conversion kits in the marine vehicle may cause cylinder rusting within a very short span of use in freshwater/sea. Because of the above discussed problems, usage of LPG fuel in marine vehicles has become very unpopular despite of such available system.

Therefore, there exists a need to provide a LPG conversion kit for providing freeze free, safe and reliable operation of a marine vehicle.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1 illustrates an exemplary block diagram of an integrated portable liquefied petroleum gas (LPG) bunker cum fuel system for marine vehicles, according to one embodiment.

Figure 2 is an exploded view of the prime control unit such as those shown in Figure 1, according to one embodiment.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an integrated portable liquefied petroleum gas (LPG) bunker cum fuel system for marine vehicles. Aspects of the invention are disclosed in the following description and related drawings directed to specific embodiments of the invention. Alternate embodiments may be devised without departing from the spirit or the scope of the invention. Additionally, well-known elements of exemplary embodiments of the invention will not be described in detail or will be omitted so as not to obscure relevant details of the invention.

The terms 'integrated portable LPG bunker cum fuel system' and 'portable LPG bunker' are used interchangeably throughout the document.

Figure 1 illustrates an exemplary block diagram of an integrated portable LPG bunker cum fuel system 100 for marine vehicles, according to one embodiment. The portable LPG bunker 100 is connected to a marine outboard engine 118 (e.g., of capacity 9.9 horse power to 27 horse power) of a marine vehicle for operating the marine outboard engine 118, basically meant for running on gasoline or kerosene, using liquefied petroleum gas in a freeze-free manner. The portable LPG bunker 100 includes three horizontal flat fuel tanks 102A-C made of non-corrosive material, multi-function valves 104A-C, junction box 106, a solenoid valve 108, a pressure regulator 110, a prime control unit 112, a snap-on connector 114, a lubrication unit 115, and an earthing unit 116.

Each of the fuel tanks 102A-C contains maximum 80% of liquefied petroleum gas in liquid form and 20% of liquefied petroleum gas in vapour form. The fuel is filled in the fuel tanks 102A-C using the multi-function valves 104A-C through a land based dispensing unit or a marine LPG dispensing unit. When the level of LPG in each of the fuel tanks 102A-C reaches 80% of its volume, the respective multi-function valves 104A-C stops the LPG filling process.

In an exemplary operation, the multi-function valves 104A-C withdraws desired amount of LPG in vapour form from the respective fuel tanks 102A-C and supplies the LPG in vapour form to the junction box 106. It can be noted that, one or more of the multi-function valves 104A-C supplies the LPG in vapour form to the junction box 106 based on the demand. For example, the demand for LPG may increase with increase in speed of the marine vehicle (i.e., when revolutions per minute of the marine outboard engine 118 increases). When the demand becomes high, all the multi-function valves 104A-C supplies the LPG in vapour form to the junction box 106. It can be noted that, withdrawal of desired * amount of vapour LPG simultaneously from multiple fuel tanks 102A-C ensures that the temperature of fuel in the fuel tanks 102A-C does not drop to a freezing temperature and also required amount of vapour LPG is supplied to the engine 118 as per the demand in an uninterrupted manner. On the contrary, when the demand is low, one of the multi-function valves 104A-C needs to supply the LPG to the junction box 106. The operation of multi-function valves 104A-C can be controlled via an actuator mechanism (not shown) which actuates one or more multi-function valves 104A-C based on RPM of the marine outboard engine 118.

In some embodiments, when the marine outboard engine 118 is turned ON, the solenoid valve 108 connected to an ignition system (not shown) of the marine vehicle gets automatically actuated. As a consequence, the solenoid valve 108 allows the LPG in vapour form to flow from the respective multi-function valves 104A-G to the junction box 106. The junction box 106 supplies desired amount of LPG in vapour form to the pressure regulator 110. The pressure regulator 110 steps down the pressure of the LPG in vapour form to standard pressure (e.g., 600 water column) and forwards the low pressure LPG vapour to the prime control unit 112.

The prime control unit 112 provides required amount of LPG in vapour form to an air-fuel mixer 120 based on the vacuum inside the marine outboard engine 118. In one embodiment, the prime control unit 112 senses a suction pressure in the marine outboard engine 118 and supplies the required amount of the LPG in vapour form to the air-fuei mixer 120. For example, the prime control unit 112 senses the vacuum through a vacuum hose 122 connecting the prime control unit 112 and a carburettor 124 of the marine outboard engine 118. The air-fuel mixer 120 mixes air with the vapour LPG and feds the air-LPG mixture to the marine outboard engine 118 via the carburettor 124 to run the engine 118.

The prime control unit 112 also acts as a backfire deflector to prevent the fuel tanks 102A-C and other components from a positive wave formed in the engine manifold when a backfire takes place in the marine outboard engine 118. The snap-on connector 114 automatically shuts off the supply of LPG when the hose connecting the marine outboard engine 118 detaches from the marine outboard engine 118 due to turbulence or accident.

Additionally, if the engine 118 requires lubrication for its operation, then the lubrication unit 115 provides required amount of lubricant to the marine outboard engine 118 based on RPM of the marine outboard engine 118. As shown in Figure 1, the lubrication unit 115 includes an oil reservoir 126, an oil pump 128, and an oil jet 130. In exemplary implementation, the oil reservoir 126 reads the RPM of the engine 118 and feeds the lubricant to the carburettor 124 via the oil jet 130. The portable LPG bunker 100 also includes the earthing unit 116 connected to the fuel tanks 102A-C and other metallic components for discharging charges generated during LPG filling process into a water body, thereby providing cathodic protection to metallic components of the LPG portable bunker 100.

Figure 2 is an exploded view of the prime control unit 112 such as those shown in Figure 1, according to one embodiment. As described earlier, the prime control unit 112 is a mechanical device having components to supply LPG in vapour form to the marine outboard engine 118 as per the operating conditions of the engine 118. The exploded view of the prime control unit 112 depicts different mechanical components for working of the prime control unit 112. The said mechanical components include a vacuum diaphragm 202, a control lever 204, a main fuel control 206, and an atmospheric diaphragm 208.

The prime control unit 112 received the low pressure LPG in vapour form via an input collar 210. When the engine 118 is started, the vacuum diaphragm 202 senses a suction pressure in the prime control unit 112 through a vacuum connector 212 connecting an engine manifold and the prime control unit 112. Accordingly, the vacuum diaphragm 202 opens the control lever 204 via a magnet placed on top of the vacuum diaphragm 202, thereby allowing vapour LPG to flow through the main fuel control 206 to the marine outboard engine 118 via the air-fuel mixer 120. The vacuum in the engine 118 also acts on the atmospheric diaphragm 208 which helps control the gas flow as per the operational conditions of the engine 118.

According to the foregoing description, the present invention uses the horizontal flat fuel tanks 102A-C as they occupy less space and supply required amount of LPG in vapour form to the marine outboard engine 118. Further, the fuel tanks 102A-C are integrated part of the fuel conversion kit 100 and are portable and non-replaceable fuel tanks placed on the floor of the marine vehicle.

The present invention facilitates in quickly starting the marine outboard engine 118, good power and pick up, thereby eliminating the risk of engine slow down and toppling of the marine vehicle. The present invention also provides reduced fuel consumption, reduction in emission, enhanced engine life, enhanced engine oil life, reduced cost of running and maintenance with safety use of LPG. As discussed above, the present invention eliminates seizing of the engine 118, and cooling and freezing of fuel tanks 102A-C.

The foregoing description and accompanying drawings illustrate the principles, preferred embodiments and modes of operation of the invention. However, the invention should not be construed as being limited to the particular embodiments discussed above. Additional variations of the embodiments discussed above will be appreciated by those skilled in the art.

Therefore, the above-described embodiments should be regarded as illustrative rather than restrictive. Accordingly, it should be appreciated that variations to those embodiments can be made by those skilled in the art without departing from the scope of the invention as defined by the following claims.

We Claim:

1. An apparatus for providing freeze-free operation of a marine vehicle, comprising:

at least three fuel tanks adapted for storing liquefied petroleum gas;

at least three multi-function valves disposed on the at least three fuel tanks, each of the at least three multi-function valves adapted for withdrawing a desired amount of the stored LPG in vapour form from respective one of the at least three fuel tanks;

a pressure regulator connected to the at least three multi-function valves and adapted for reducing the pressure of the withdrawn LPG in vapour form to a standard pressure; and

a prime control unit connected to the pressure regulator and adapted for providing a required amount of the LPG in vapour form to an engine of the marine vehicle via an throttling mechanism of the marine vehicle to provide freeze-free operation of the marine vehicle.

2. The apparatus of claim 1, further comprising:

a solenoid valve mounted on each of the at least three multi-function valves and adapted for supplying the withdrawn LPG in vapour form to the pressure regulator when the engine is turned on.

3. The apparatus of claim 1, further comprising:

a lubrication unit connected to the engine via the throttling mechanism and adapted for providing a required amount of lubricant to the engine based on operating conditions of the engine.

4. The apparatus of claim 1, further comprising:

a snap-on connector adapted for preventing leakage of the vapour LPG when a hose connecting the engine is detaches from the engine.

5. The, apparatus of claim 1, wherein each of the at least three fuel tanks comprises a horizontal flat fuel tank made of non-corrosive material.

6. The apparatus of claim 1, wherein each of the at least three multi-function valves is adapted for receiving LPG from a LPG filling unit and storing the LPG in the respective one of the at least three fuel tanks.

7. The apparatus of claim 6, wherein each of the at least three multi-function valves is adapted for stopping the LPG filling process when the level of LPG in the respective one of the at least three fuel tanks reaches a threshold limit.

8. The apparatus of claim 1, further comprising:

an earthing unit connected to each of the at least three fuel tanks for discharging charges generated during LPG filling process into a water body.

9. The apparatus of claim 1, wherein the prime control unit is adapted for preventing the at least three fuel tanks from a positive wave formed in an engine manifold due to backfire in the engine.

10. The apparatus of claim 8, wherein the prime control unit provides the required amount of withdrawn LPG in vapour form to the engine based on a vacuum pressure inside the engine.

11. A system for provide freeze-free operation of a marine vehicle comprising:

an engine adapted to run a marine vehicle on a liquefied petroleum gas (LPG); and

a portable LPG bunker connected to the engine and adapted to supply a required amount of LPG in vapour form to the engine, wherein the portable LPG bunker comprises:

at least three fuel tanks adapted for storing LPG;

at least three multi-function valves disposed on the at least three fuel tanks, each of the at least three multi-function valves is adapted for withdrawing a desired amount of the stored LPG in a vapour form the respective one of the three fuel tanks;

a solenoid valve mounted on each of the at least three multi-function valves and adapted for supplying the withdrawn LPG in vapour form when the engine is turned ON;

a pressure regulator connected to the solenoid valve and adapted for reducing the pressure of the withdrawn LPG in vapour form to a standard pressure;

a prime control unit connected to the pressure regulator and adapted for providing a required amount of the LPG in vapour form to an engine of the marine vehicle via an throttling mechanism of the marine vehicle; and

a lubrication unit connected to the engine via the throttling mechanism and adapted for providing a required amount of lubricant to the engine based on operating conditions of the engine.