Description:Field of the invention

The present invention generally relates to Liquefied Petroleum Gas (LPG) withdrawal system for marine engines and more particularly it relates to a LPG kit with liquid withdrawal system for multi-stroke gasoline (Petrol/Petrol start kerosene run) marine engines.

Background of the invention

In the marine sector, the quick adaptation of LPG as a fuel would be a great step forward for the environment, cleaner air, and cleaner water. With its lower cost of implementation and its readily available infrastructure, LPG, exceptional energy, has significant advantages over other alternative fuels. The benefits of LPG to the marine industries are numerous and substantial as no gasoline pollutes the water, virtually eliminating particulate emissions that turn into methyl mercury in the water, the available power of internal combustion engines without the environmental detriment of gasoline, extended engine life, and reduced cost of operation. Many Marine LPG kits are available in the market. Marine engines employ an LPG vapor withdrawal system. In such a system LPG is withdrawn from the cylinder in a gaseous state, and the vaporization takes place in the cylinder itself. As the LPG consumption increases due to the higher fuel demand from the Engine, the vaporization rate of liquid LPG inside the cylinder steadily increases, due to this the LPG cylinder temperature reduces to such an extent that it even goes below zero degrees, resulting in a reduced supply of gaseous LPG from the cylinder and further stopping of the Engine itself. Such systems therefore either restrain the engine power capacity or necessitate the use of large-capacity or multiple cylinder bank. Multiple cylinders occupy a major space in small fishing vessels and also add unnecessary weight to the boat. This ultimately results in loss of speed, less storage space for the catch, and requires more fuel to run the engine.

The patent document JP2019178645 discloses an outboard engine. The document discloses an arrangement to inhibit the evaporation of fuel in a fuel tank as much as possible in an outboard engine. The outboard engine includes an engine 30 and a tank body 34 of a fuel tank 32 is housed in a casing 16 of an outboard engine 10a. A large portion of an outer wall of the tank body 34 is enclosed by a water jacket 50a. A cooling medium (for example, water W) circulates in the water jacket 50a. The cooling medium cools a fuel in the fuel tank 32. The water jacket 50a is a cooling medium flow passage in which the cooling medium for cooling the fuel circulates. The cooling medium flow passage is configured as a water jacket provided on an outer wall of the fuel tank.

The patent document US6093067 discloses a cooling structure for an outboard engine having a cooling water piping of reduced length and simplified construction. In the outboard engine that cools its engine with cooling water to be led from the outside, a water check port is provided in the middle of its cooling water passage. Moreover, a vapor separator is provided on fuel supply equipment. In addition, a water passage for the water check port is provided so as to branch in the middle of the cooling water passage for a vapor separator. As such, the cooling water is led to the vapor separator and the water check port is located at the inlet of the cooling water before cooling of the engine.

The patent document JP2003097377 discloses a fuel feeder of an outboard engine. The outboard engine has a fuel feeder comprising a vapor separator into which fuel from a fuel tank provided on a hull side is led, an injector to inject the fuel into an intake port, and a fuel pump to pump the fuel in the vapor separator into the injector. Fuel system parts including fuel filters and the fuel pump to lead the fuel from the fuel tank to an engine, the vapor separator, a delivery pipe, and the injector are concentrated on one side surface on which an intake manifold of a cylinder block is disposed. The vapor separator is fixed to a plurality of intake pipes that are arrayed in the vertical direction by bolts and the heads of the bolts are disposed of between the intake pipes.

In documents JP2019178645, US6093067, and JP2003097377 LPG is withdrawn from the cylinder in a gaseous state, and the vaporization takes place in the cylinder itself. When the LPG consumption increases due to the higher fuel demand from the Engine, the vaporization rate of liquid LPG inside the cylinder steadily increases. Further, the LPG cylinder temperature reduces to such an extent that it even goes below zero degrees, resulting in a reduced supply of gaseous LPG from the cylinder and further stopping of the Engine itself. Thus, the systems where the LPG vaporization takes place in the cylinder either restrain the engine power capacity or necessitate the use of large-capacity or multiple cylinder bank. Multiple cylinders occupy a major space in small fishing vessels and also add unnecessary weight to the boat. This ultimately results in a loss of speed, less storage space for the catch, and requires more fuel to run the engine.

Accordingly, there exists a need to provide a liquid withdrawal system where the LPG vaporization takes place outside of the cylinder for multi-stroke gasoline (Petrol/Petrol start kerosene run) marine engines that overcome the drawbacks in the prior art.

Objects of the invention:

• An object of the present invention is to provide a leakage-proof LPG kit for a marine engine.
• Another object of the present invention is to provide a safe liquid LPG withdrawal system.
• Yet, another object of the present invention is to provide filtered fuel to the marine engine.
• Yet, another object of the present invention is to provide a leakage-proof LPG kit suitable to run the marine engine in bi-fuel mode i.e. on LPG or Petrol + Kerosene (One fuel at a time).
• Yet, another object of the present invention is to provide an economic and eco-friendly leakproof LPG kit to run the marine engine.
• A further object of the present invention is to provide an LPG kit with a liquid LPG withdrawal system that is suitable to use in a single LPG cylinder instead of bank of LPG cylinders supplying gaseous LPG. The weight of a single LPG cylinder with liquid system is considerably low as compared to the bank of LPG cylinders supplying gaseous LPG. This reduces load of LPG cylinder on fishing boat which helps for increasing the speed of fishing boat.
• A still further object of the present invention is to provide an LPG kit with liquid LPG withdrawal system using a single cylinder against a bank of LPG cylinders, which is required for gaseous LPG supply. This reduces the space occupied by the bank of cylinders thereby providing more storage space in the fishing boats to store caught fishes.
• Still one more object of the present invention is to run multiple outboard engines fitted on a big marine vessel, using a single leakage proof LPG kit with liquid withdrawal system without any major changes, or modifications.

Summary of the Invention

Leakage-proof LPG kit for a marine engine with a liquid withdrawal system is fitted on LPG cylinder. The system comprises a LPG regulator, intake manifold and pistons; a vacuum nozzle; a vacuum hose. The LPG regulator is configured to vaporize the LPG with hot water. The LPG regulator includes a vacuum diaphragm, a spring, a lever, and liquid LPG withdrawal system.

The liquid withdrawal system comprises a replaceable LPG cylinder, a liquid withdrawal cylinder valve, a dip tube, a valve adaptor, a hose tube, LPG Filter, a manual ON/OFF valve, a gas flow control unit. A liquid withdrawal cylinder valve is fitted at the neck of the LPG cylinder. The dip tube being fixed at the lower end of the liquid withdrawal cylinder valve. The dip tube enters said LPG cylinder till the bottom and remains dipped in liquid LPG. The valve adaptor is fitted on the cylinder valve with a knob or hand wheel to turn on or off the LPG supply. The second end of adaptor is connected to an LPG filter through a hose tube. The LPG filter is connected to the LPG regulator through the hose tube. The manual ON/OFF valve is connected to the outlet of the LPG regulator through the hose tube. The gas flow control unit is fitted to the outlet of manual ON/OFF valve. The gas-air mixer unit is fitted on the carburetor air intake side adjacent to the air box of the marine engine. The air mixer unit and the gas flow control unit are connected by an LPG hose tube.

The leakage-proof LPG kit for marine engines with a liquid withdrawal system includes a two-stage regulator to eliminate LPG leakage during engine off conditions through the vacuum circuit spring. The vacuum circuit spring is fitted at the second stage of the LPG regulator. When the marine engine starts, the engine suction creates a vacuum or negative pressure in the intake manifold by moving the piston. The negative pressure acts on the diaphragm such that, the spring gets pushed in the downward direction and opens the lever. Further, the opening of the lever allows the flow of LPG vapor to the outlet of the LPG regulator. When the marine engine is switched off or not in use, there is no vacuum inside the intake manifold. In the absence of a vacuum, the spring expands and pushes the vacuum diaphragm. Further, the vacuum diaphragm pushes the second stage lever in an upward direction to restrict the flow of LPG vapor and inhibits the supply of vapor LPG at the outlet of the LPG regulator.

Brief description of the drawings

The embodiments can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, the emphasis instead being placed upon illustrating the principles of the embodiments. Moreover, the figures, like reference numerals designate corresponding parts throughout the different views.

Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.

The above and other objects, features, and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

Figure 1 illustrates a leakage-proof LPG kit for a marine engine with a liquid withdrawal system, in accordance with the present invention;

Figure 2 illustrates a leakage-proof LPG kit for a marine engine with a liquid withdrawal system for 2-stroke marine engines, in accordance with the present invention;

Figure 3 illustrates a leakage-proof LPG kit for a marine engine with a liquid withdrawal system for 4-stroke marine engines, in accordance with the present invention;

Figure 4 illustrates a prior art LPG liquid withdrawal system for a marine engine.

Detailed description of the invention:

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques, and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention provides a leakage proof LPG kit with a liquid withdrawal system for marine engine. The leakage proof kit includes a two stage LPG regulator that vaporizes the LPG outside the cylinder using hot water. The LPG vapor is supplied to the engine due to engine suction created by the moving pistons of the engine. The vacuum inside the manifold acts on a spring of the regulator that prevents leakage of LPG when the engine remains off.

The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in brackets in the following description and in the table below.
REFERENCE NUMERAL COMPONENT REFERENCE NUMERAL COMPONENT
101 LPG CYLINDER 116 BALL VALVE
102 LIQUID LPG
WITHDRAWAL VALVE 117 BALL VALVE
103 DIP TUBE 118 PETROL TANK
104 ADAPTOR 119 PETROL FILTER
105 TWO-STAGE LPG REGULATOR 120 T-CONNECTOR
106 HOSE TUBE ADAPTOR TO GAS FILTER 121 VACUUM HOSE T- CONNECTOR TO OIL VALVE
107 GAS FLOW CONTROL
UNIT 122 JUNCTION BTWO-STAGE)
108 GAS-AIR MIXER UNIT 123 JUNCTION BLOCK (PETROL)
109 ENGINE 124 JUNCTION BLOCK (OIL)
110 HOSE TUBE REGULATOR
TO ENGINE 125 OIL TANK
111 HOSE TUBE GAS FILTER
TO REGULATOR 126 VACUUM-OPERATED
VALVE (OIL)
112 VACUUM HOSE ENGINE TO REGULATOR 127 OIL FLOW CONTROL UNIT
113 HOT WATER CIRCULATION
HOSE 128 OIL HOSE
114 CAR BURETOR 129 GAS FILTER
115 MANUAL ON/OFF VALVE

Referring Figure 1, Figure 1 illustrates a leakage-proof LPG kit with a liquid withdrawal system for marine engine (hereinafter, “the system (100)”). The system (100) comprises a two-stage LPG regulator (105); an intake manifold (401); a vacuum nozzle (402); a vacuum hose (112); a piston; a vacuum circuit spring (404); a vacuum diaphragm (403); and an LPG withdrawal unit.

The two-stage regulator is configured to vaporize the LPG. The two-stage LPG regulator (105) includes a second-stage lever (405). The vacuum hose (112), and the nozzle (402) connect the two-stage regulator to the engine manifold. The vacuum circuit spring (404) is being fitted at the second stage of the two-stage regulator (105). In one of the aspects of the present invention, the LPG kit is fitted with a liquid withdrawal system where the hot/warm water from engine water jackets is connected to the regulator through the hot water circulation hoses. The hot water vaporizes the liquid LPG to gaseous LPG.

The LPG withdrawal unit of the system (100) comprises a replaceable LPG cylinder (101). A liquid withdrawal cylinder valve (102) is fitted at the neck of the LPG cylinder (101). A dip tube (103) is fixed at the lower end of the liquid withdrawal cylinder valve (102). A valve adaptor (104) is fitted on the cylinder valve (102) with a knob or hand wheel to turn on or off the LPG supply. An LPG Filter (129) is connected to the LPG regulator (105) through a hose tube (111). An adaptor (104) is connected to the LPG filter (129) through a hose tube (106). A manual ON/OFF valve (115) is connected to the outlet of the LPG regulator (105) through the hose tube (110). A gas flow control unit (107) is fitted to the outlet of the manual ON/OFF valve (115). The gas flow control unit (107) is connected by to an air mixer unit (108) by an LPG hose tube (110). The gas-air mixer unit (108) is fitted on the carburetor air intake side adjacent to the air box of the marine engine (109). An oil tank (125) is connected to the vacuum-operated valve (126). Further, the vacuum-operated valve (126) is connected to an oil flow control unit (127). An oil hose (128) connects the oil flow control unit (127) to the gas-air mixer unit (108).

The outlet of the liquid withdrawal cylinder valve (102) is configured to hold the LPG valve adaptor (104). A collar of the outlet of the liquid withdrawal cylinder valve (102) is preferably provided with a seal and internal profile to make it a leakproof tight joint with the adaptor. The LPG cylinder valve (102) essentially comprises a metal forged body that accommodates a valve assembly. The metal forged body has a lower stub portion provided with taper threads suitable for making a leakproof joint with threads of the bungs of replaceable LPG cylinder (101). Additionally, the metal forged body accommodates an excess flow check valve and a dip tube. The excess flow check valve is provided at the lower end of the valve body. The dip tube is fixed at the bottom of the valve body such that the LPG vapor should not pass to the regulator. Further, the length of the tube is maintained such that it should remain just above the inner bottom surface of the LPG cylinder to facilitate maximum liquid withdrawal.

In an operation of the system (100), when the marine engine starts, the engine suction creates a vacuum or negative pressure in the intake manifold (401) by moving the piston. The negative pressure acts on the diaphragm (403) such that, the spring (404) gets pushed in the downward direction and opens the lever (405). Further, the opening of the lever (405) allows the flow of LPG vapor to the outlet of the LPG regulator (105). When the marine engine is switched off or not in use, there is no vacuum inside the intake manifold. In the absence of a vacuum, the spring (404) expands and pushes the vacuum diaphragm (403). Further, the vacuum diaphragm pushes the second stage lever (405) in an upward (vertical) direction to restrict the flow of LPG vapor and inhibits the supply of vapor LPG completely at the outlet of the LPG regulator (105), and makes the LPG kit leakage proof.

In accordance with the invention, the LPG kit is preferably adapted for a 2- stroke and a 4- stroke engine. The engine runs in the bi-fuel mode. In bi- fuel mode, the LPG cylinder contains 80% liquid LPG of its volume.

In another aspect of the present invention, the 2 stroke engine is provided with a lubrication system where the engine runs on LPG fuel, and oil is supplied to the engine through the vacuum-operated on/off valve (126). One end of the vacuum-operated valve is connected to the engine manifold for sensing the vacuum. The flow control unit (127) is connected to the oil hose (128).

Referring to Figure 2, a leakage proof LPG kit with liquid withdrawal assembly for a 2-stroke marine engine is illustrated in accordance with the present invention. In preferred embodiment of the invention, the 2-stroke marine engine is a bi-fuel engine. The bi fuel engine includes a replaceable LPG cylinder (101) that contains liquid LPG up to 80% of its volume. The liquid withdrawal cylinder valve (102) is fitted at the neck of the cylinder (101). The dip tube (103) is fitted at the lower end of the valve that enters the LPG cylinder (101) and extends up to its inner bottom surface such that it remains dipped in the liquid LPG. The valve adaptor (104) is fitted on the said cylinder valve (102). The valve (102) is provided with the hand wheel to turn on or off the LPG supply to the engine. The adaptor (104) is connected to an LPG filter (129) through a hose tube (106). The LPG filter (129) is connected to the inlet of the LPG regulator (105) through a hose tube (111). The hose tube (110) is fitted to the outlet of the LPG regulator (105). The manual ON/OFF valve (115) is connected to the outlet of the LPG regulator (105) through the hose tube (110). The gas flow control valve (107) is fitted to the outlet of the ON/OFF valve (115). The gas-air mixer unit (108) is fitted on the carburetor air intake side and placed adjacent to the air box of the engine (109). The mixer unit (108) and the gas flow control unit (107) are connected by the LPG hose tube (110). The engine jacket and the LPG regulator are connected by a hot water circulation hose (113) to vaporize liquid LPG to gaseous LPG. The LPG regulator’s vacuum port and the engine manifold are connected by a vacuum hose (112). The system further includes the oil tank (125), the vacuum operated on/off valve (126), and an oil flow control unit (127). The oil Tank (125) is connected to the vacuum operated valve by an oil hose (128) and the vacuum valve (126) is connected to the engine, the oil flow control unit (127), and the mixer unit (108) by the oil hose (128).

In the case of the 2 stroke engine, a lubrication system is required when the engine is being run on LPG fuel. However, a separate lubrication system is not required for 4-stroke engine.

Now, referring to Figure 2, the typical structure and workflow of an improved LPG regulator (105) for a 2-stroke marine engine is explained, in accordance with the present invention. In 2-stroke marine engine, the liquid LPG is withdrawn from the replaceable LPG cylinder (101) by the cylinder valve (102) through the dip tube (103). The liquid LPG is supplied through the valve adaptor (104) to the LPG filter (129) by an LPG hose (106) and then from the LPG filter (129) to the LPG regulator (105) by the LPG hose tube (111). The liquid LPG is converted into vapor in the LPG regulator (105) by the heat of the circulating water from the engine jacket connected to the LPG regulator (105) through the water circulation hose (113). Further, the LPG vapor is supplied to the engine due to engine suction created by the moving piston. The amount of LPG supplied is controlled by the gas flow control unit (107) fitted at the outlet of the LPG regulator by the hose tube (110). The gas and the air entering the engine (109) are mixed together in the gas air mixer (108) fitted on the intake side of the carburetor from where the mixture of gas and air is supplied to the engine for combustion and for generating the required power. The valve (126) of the oil tank (125) gets open due to a vacuum and oil flows to the engine through the oil hose (128). When the 2-stroke marine engine gets switched off, there is no vacuum inside the intake manifold. In the absence of a vacuum, the spring (404) expands and pushes the vacuum diaphragm (403) and the second stage lever (405) upward (vertical) direction to stop the flow of vapor LPG and stop the supply of vapor LPG completely at the outlet of the LPG regulator (105) to the engine and makes the LPG kit as leakage proof system.

Now, referring to Figure 3, a typical structure and workflow of a leakage-proof LPG kit fitted with a liquid withdrawal assembly for a 4-stroke marine engine is explained, in accordance with the present invention. The liquid LPG is withdrawn from the replaceable LPG cylinder (101) by the cylinder valve (102) through its dip tube (103) which is dipped in liquid LPG. The liquid LPG is supplied through the valve adaptor (104) to the LPG filter (129) through an LPG hose (106) and further, from the LPG filter (129) to the LPG regulator (105) through the LPG hose tube (111). The LPG regulator (105) vaporizes (105) the liquid LPG by heat of the circulating water from the engine jacket through the water circulation hose (113). Further, the LPG vapor is supplied to the engine due to engine suction created by the moving pistons of the engine. The supply of vapor LPG to the engine is controlled by the gas flow control unit (107) fitted at the outlet of the LPG regulator through the hose tube (110). The gas and the air entering the engine (109) are mixed together in the gas air mixer (108) fitted at the intake side of the carburetor from where the mixture of gas and air is supplied to the engine for combustion and for generating the required power. If the 4- stroke marine engine gets switched off, the vacuum is absent inside the intake manifold. In the absence of a vacuum, the spring (404) expands and pushes the vacuum diaphragm (403) and the second stage lever (405) in an upward (vertical) direction to inhibit the flow of vapor LPG and stop the supply of vapor LPG completely at the outlet of the LPG regulator (105) to the engine and makes the LPG kit as leakage proof system.

Advantages of the invention:

1. Leakage-proof LPG kit fitted with a liquid withdrawal assembly, used in various watercraft, fishing boats/houseboats and marine vessels.

2. Leakage-proof LPG kit fitted with a liquid withdrawal assembly is efficient for 2 stroke as well as for 4 strokes single and multi-cylinder outboard motors and other engines for marine applications.

3. Leakage-proof LPG kit fitted with a liquid withdrawal assembly employs a vacuum created by engine suction and a vacuum circuit spring, that provides LPG supply to the engine during on condition, stops the supply in Off condition and eliminates the chance or risk of LPG leakage and makes the LPG kit as leakage proof system.

4. Leakage-proof LPG kit fitted with a liquid withdrawal assembly provides clean and filtered fuel to the marine engine.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described for best explaining the principles of the present invention and its practical application, to thereby enable others skilled in the art for best utilizing the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.
, Claims:We claim:

1. Leakage-proof LPG kit with liquid withdrawal system for a marine engine comprises:
a replaceable LPG cylinder (101);
a liquid withdrawal cylinder valve (102) fitted at the neck of the LPG cylinder (101);
a dip tube (103) being fixed at the lower end of the liquid withdrawal cylinder valve (102)
a valve adaptor (104) being fitted on the cylinder valve (102) with a knob or hand wheel to turn on or off the LPG supply;
an adaptor (104) connected to an LPG filter (129) through a hose tube (106), the LPG Filter (129) being connected to the LPG regulator (105) through a hose tube (111);
a manual ON/OFF valve (115), the valve (115) being connected to the outlet of the LPG regulator (105) through a hose tube(110);
a gas flow control unit (107) being fitted to the outlet of the manual ON/OFF valve (115);
a gas-air mixer unit (108), the gas-air mixer unit (108) being fitted on the carburetor air intake side adjacent to the air box of the marine engine (109), the air mixer unit (108) and the gas flow control unit (107) being connected by an LPG hose tube (110);
an oil tank (125) being connected to the vacuum-operated valve (126) that is further connected to an oil flow control unit (127);
an oil hose (128), the oil hose connects the oil flow control unit (127) to the gas-air mixer unit (108);
a LPG the hot water circulation hoses (113) being connected to the engine water jacket and the LPG regulator, the hot water circulation hoses (113) vaporizes the LPG by the hot water received from the engine;
characterized in that,
a two-stage regulator (105) having a second stage lever (405), the two-stage regulator is configured to vaporize the LPG;
an intake manifold (401);
a vacuum nozzle (402);
a vacuum hose (112), the vacuum hose (112), and the nozzle (402) connect the two-stage regulator to the engine manifold;
a piston;
a vacuum circuit spring (404), the vacuum circuit spring (404) is being fitted at the second stage of the two-stage regulator (105);
a vacuum diaphragm (403);
wherein the running engine suction creates a vacuum/ negative pressure in the intake manifold (401) by moving the piston that acts on the diaphragm (403) to push the spring (404) in the downward direction causing the opening of the lever (405) that allows the flow of the LPG vapor to the outlet of the LPG regulator and opening of vacuum-operated valve (126) that allows the flow of oil to the engine,
whereas the absence of vacuum due to off engine expands the spring ( 404) that pushes the diaphragm (403) and the second stage lever (405) in an upward (vertical) direction that closes the lever (405) and restricts the flow of LPG vapor supply to the outlet of the LPG regulator.

2. Leakage-proof LPG kit fitted with a liquid withdrawal system for a marine engine as claimed in claim 1, wherein the second stage of LPG regulator reduces the pressure of the vaporized LPG to the atmospheric pressure and supplies it to the gas-air mixer.

3. Leakage-proof LPG kit fitted with a liquid withdrawal system for a marine engine as claimed in claim 1, wherein the outlet of the liquid withdrawal cylinder valve (102) is configured to hold the LPG valve adaptor (104),

4. Leakage-proof LPG kit fitted with a liquid withdrawal system for a marine engine as claimed in claim 1, wherein the collar of the outlet of the liquid withdrawal cylinder valve is provided with a seal, internal profile, and an excess flow check valve.
5. Leakage-proof LPG kit fitted with a liquid withdrawal system for a marine engine as claimed in claim 1, wherein the metallic dip tube is fixed at the bottom of the cylinder valve body.