Claims:WE CLAIM:

1. The method of conversion of diesel fuelled engine vehicle into liquefied natural gas fuelled vehicle comprising:
a. modified diesel engine (14) consisting of:
i. installing spark plug (18) on cylinder head by removing the fuel injector;
ii. replacing the diesel engine piston with NG piston (20);
b. installation of liquefied natural gas fuel system comprises;
i. a tank (1) configured to store liquefied natural gas;
ii. a Heart-exchanger (2) converts liquefied natural gas into natural gas.

2. The method of conversion of diesel fuelled engine vehicle into liquefied natural gas fuelled vehicle as claimed in claim 1, wherein the spark plugs (18) are installed with the ignition system that is used to generate a spark on electrode to a high temperature to ignite a fuel-air mixture in the modified diesel engine (14).

3. The method of conversion of diesel fuelled engine vehicle into liquefied natural gas fuelled vehicle as claimed in claim 1, the NG piston (20) that is used in compressed natural gas engine and petrol engine that has characteristic low thermal conductivity and having a combustion bowl (16) can be used in the present invention.
4. The method of conversion of diesel fuelled engine vehicle into liquefied natural gas fuelled vehicle as claimed in claim 1, the NG piston (20) has three or more piston rings (17) wherein two piston rings are plain faced rings and third piston rings is oil control ring.

5. The method of conversion of diesel fuelled engine vehicle into liquefied natural gas fuelled vehicle as claimed in claim 1, where in fuel system comprises:
i. the liquefied natural gas storage tank (1) is used to store liquefied natural gas has a material with extremely efficient insulation between the outer surface and inner surface of the tank and has pressure range is around 04-24 bar;
ii. the liquefied natural gas is delivered through heat exchanger (2), gas reducer (7), air-gas mixture (11), throttle body (12) to the modified diesel engine (14).

6. The method of conversion of diesel fuelled engine vehicle into liquefied natural gas fuelled vehicle as claimed in claim 4, wherein

i. heat exchanger (2) is used to convert liquefied natural gas into natural gas at atmospheric temperature, wherein the coolant has temperature is around 500C to 600C is used as a heat source in heart-exchanger (2);
ii. gas reducer (7) is control the pressure required for supply of gas to the engine;
iii. air-gas mixture (11) is used to mix proper amount of compressed air comes from the turbocharger and natural gas;
iv. throttle body (12) is connected with the accelerator (not shown in figure) that regulates the flow of mixture to the engine (14) and accelerates the vehicles.

7. The method of conversion of diesel fuelled engine vehicle into liquefied natural gas fuelled vehicle as claimed in claim 1,where in backup fuel system comprises:
i. compressed natural gas cylinders (6);
ii. 3-way L-port ball valve (5);
iii. the compressed natural gas is delivered through 3-way L-port ball valve (5), gas reducer (7), air-gas mixture (11), throttle body (12) to the modified diesel engine (14).

8. The method of conversion of diesel fuelled engine vehicle into liquefied natural gas fuelled vehicle as claimed in claim 8,where in compressed natural gas fuel system comprises:
i. compressed natural gas cylinders (6) is used to store compressed natural gas having a pressure range 200-220 bar;
ii. 3-way L-port ball valve (5) is a valve which is used to switch over from LNG to CNG and vice-versa.
, Description:FIELD OF THE INVENTION:
The present invention relates to convert the diesel-fuelled engine of vehicles into LNG fuelled engine vehicles. The present invention generally relates to a fuel system in which cryogenic fluid is used to produce power from the internal combustion engine. More especially invention relates to modified engines of any vehicle that are running on internal combustion engine so efficiency and load carrying capacity is increased.

BACK GROUND OF THE INVENTION:
Vehicles have been propelled with fuel that is petrol, diesel, kerosene, liquefied petroleum gas, etc. These fuels contain paraffin hydrocarbon group. There is greater chance of incomplete combustion and residual carbon deposits in the atmosphere. These fuels provide a dense exhaust fume as a by-product of combustion like CO, CO2, NOx, etc. Gasoline compounds contain petroleum, octane, diesel, LPG, butane, etc. By using diesel or gasoline in the vehicles cannot run longer kilometres with one time refuel the storage tank. It is not possible to increase the storage volume as it leads to increase the weight of the vehicle.

The present invention overcomes that problem by delivering cryogenic fuel to the internal combustion engine. Cryogenic fuels are environmentally cleaner than gasoline or fossil fuels. Among other things, the greenhouse gas rate could potentially be reduced by 11–20% using LNG as opposed to gasoline when transporting goods. The invention uses LNG as a cryogenic fuel in I.C engine of vehicles. The lower carbon deposits associated with the combustion of LNG provide for reduced maintenance cost in vehicles. LNG (Liquefied Natural Gas) basically is a liquid methane which contain approximately 90 percent to 93 percent methane, mixed with nitrogen, ethane, carbon dioxide and less than 1 percent of propane. LNG is a clean burning fuel and it is extremely safe. Economically price of the LNG fuel is less (nearly 40% or more) than other fossil fuels. The carbon in the methane completely oxidizes to a gaseous state. LNG when mixed with air provides a combustible mixture that is ideal as a source of energy for IC engine. LNG increases mileage of the IC engine than diesel engine and also increases the life of the IC engine by almost 50% or more.

Methane is a lighter fuel in weight than other fuel that is gasoline or diesel by storing natural gas in liquid form as LNG. LNG has compact density around 1 litre of LNG = 652 litre of NG (Natural Gas). Due to compact density of LNG, large amount of fuel is available which enables the driver to run longer kilometres and reduces number of refilling frequency. Cryo-energy of LNG is used for extremely efficient cooling of the engine. The other advantage of using LNG in IC engine is that LNG when exposed to ambient conditions will inherently vaporize. It is completely eliminated “preflame auto ignition” and the principle of engine “knock”.

SUMMARY OF THE INVENTION:
The principal object of the present invention is to convert diesel-fuelled engine vehicles into LNG fuelled engine vehicles by modified diesel engine.

In another object of the present invention modified diesel engine comprises: installation of spark plugs with the ignition system that is used to generate a spark on electrode to a high temperature to ignite a fuel-air mixture in the modified diesel engine.
In another object of the present invention modified diesel engine the intake valve and exhaust valve are used at times cryogenically treated to withstand more heat while combustion of natural gas.

In another object of the present invention modified diesel engine wherein the diesel engine piston are replaced with NG-Piston to increase compression ratio.

In another object of the present invention, modified diesel engine wherein, LNG is stored in LNG tank, and LNG is converted into natural gas (NG) by heat exchanger. Converted NG is flown through non-return valve, safety valve, non-return valve, 3-way L-port ball valve, gas reducer, air-gas mixture, throttle body to intake valve of the engine.

In another object of the present invention modified diesel engine wherein, heat exchanger receives heat energy for hot coolant directly from engine, which is used in the heat exchanger to convert the LNG into NG.

In another object of the present invention modified diesel engine wherein, turbocharger is attached with air-gas mixture to compress the air and increase its temperature that leads to increase the efficiency of the engine.

In another object of the present invention has backup fuel system in which compressed natural gas, using 3-way L-port ball valve. The compressed natural gas is delivered through 3-way L-port ball valve, gas reducer, air-gas mixture, and throttle body to the modified diesel engine. Compressed natural gas cylinder is used to store compressed natural gas having a pressure range 200-220 bar; 3-way L-port ball valve is used to switch over from LNG to CNG and vice-versa. This invention enables use of NG itself as backup, which is available easily and economically.

BRIEF DESCRIPTION OF THE DRAWINGS:
The drawings constitute a part of this invention and include exemplary embodiments of the present invention illustrating various objects and features thereof.
Figure 1. is a schematic diagram of a cryogenic fuel system for a vehicle;
Figure 2. is a perspective view of engine piston and piston rings.
Figure 3. is a perspective view of installed the spark plug instead of fuel injector.
Figure 4. is a schematic diagram of installed intake and exhaust valve instead of old valves that are used in diesel engine.
Figure 5. discloses ignition system of the present invention.
Figure 6. is perspective view of LNG and CNG backup system.

DETAILED DESCRIPTION OF THE INVENTION:

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

The present invention overcomes the problem related to environment pollution by conversion of diesel fuelled engine vehicle into LNG fuelled engine vehicles effectively and economically. The invention relates to major equipments that are LNG fuel tank (1), Cryo-energy based heat exchanger (2), Non-return valve (3), safety valve (4), 3-way L-port ball valve (5), Gas reducer (7), flow regulator (10), air-gas mixture (11) and throttle body (12), etc.

The present invention introducing the modified diesel engine in which LNG is used as a fuel. The modified diesel engine (14) introduces the spark plug (18) that is installed in place of fuel injector. Valves (19) are optionally changed to withstand the heat release in the engine otherwise old valve can be used. Diesel piston is also replaced with natural gas piston (NG piston) (20) to increase compression ratio. LNG is stored in LNG tank (1) and LNG is converted into NG by heat exchanger (2). Converted NG is flown through the safety valve (4), non-return valve (3), gas reducer (7), air-gas mixture (11), throttle body (12) to intake manifold of the engine intake manifold is a pipe which is connected to the inlet of the engine cylinder. The coolant is used as a heat source in the heat exchanger (2) to convert the LNG into NG.

Fig 1 illustrates a schematic diagram of LNG fuel system. LNG tank (1) that stores liquefied natural gas. The pressure range of the LNG tank (1) is around 04-24 bar. The LNG fuel is delivered to the heart-exchanger (2) with help of pressure. Heat exchanger (2) converts the state of LNG into gas with help of coolant that comes from the engine. The temperature of coolant is around 500C to 600C. Now LNG is converted in to NG (natural gas), has enough pressure to reach to the engine inlet manifold. NG flow through the non-return valve (3), safety valve (4) and 3-way L-port ball valve (5) to the gas reducer (7). Non-return valve (3) helps to flow gas from the heat exchanger (2) and restrict reverse flow of gas. Safety valve (4) is used to release the pressure whenever the pressure increases above safety valve set pressure. The gas reducer (7) controls the flow of NG. Flow regulator (10) is connected after reducer (7) that is used to control the flow of gas supplied to the engine. Air-gas mixture (10) is used to mix proper amount of compressed air comes from the turbocharger and natural gas. This mixture delivers to the engine (14) via throttle body (12). Throttle body (12) is connected with the accelerator (not shown in figure) that regulates the flow of mixture to the engine (14) and accelerates the vehicles. Vehicles includes all the present vehicle that are running on internal combustion engine that are train engine, car engine, truck engine, scooter engine, crane engine, hydra engine, earth moving equipments, tractors, and similar diesel engines etc.

One of the embodiments is that LNG tank (1) is used to store cryogenic fuel as LNG. LNG is a cryogenic fuel means it has a temperature about -162 0C. The LNG storage tank (1) is used to store LNG has a construction and material that have extremely efficient insulation between the outer surface and inner surface of the tank.

One of the embodiments is to convert diesel engines that are currently used in vehicles. To convert a diesel engine into LNG engine, cylinder head is modified, in which first step is to remove fuel injectors and precise machining is carried out in fuel injector hole to get it surfaced. The second step is to make threads in the hole to install spark plugs (18). A spark plug (18) is device for delivering electric current from an ignition system to the combustion chamber. As illustrated fuel injectors are removed, and then the holes are machined by special proprietary surfacing tool to get it surfaced and then the holes are to be threaded by threading tool so that spark plug (18) are installed. Then replace the intake and exhaust valve bodies and oil seal. New valves (19) are grinded by using grinding paste and valve gridding tool, valve seat is created, and then the valve is installed. These valves are changed so that valves can withstand more heat generated during LNG combustion. Valves are hardened by cryogenic treatment and frozen down below sub-zero temperature. A cryogenic treatment is the process of treating valves to cryogenic temperatures (i.e. below -190 °C (-310 °F)) in order to remove residual stresses and improve wear resistance on it. In addition to seeking enhanced stress relief and stabilization, or wear resistance, cryogenic treatment is also sought for its ability to improve corrosion resistance by precipitating micro-fine eta carbides, which can be measured before and after in a part using a quantimet. Diesel piston will be changed to natural gas piston (20). For that standard sized engine, sleeves are replaced and engine pistons are changed. This NG piston (20) has three piston rings (17), two rings are plain faced rings and the third piston ring is oil control ring that comprises one inner ring, helical spring ring and outer ring. This NG piston has a deep hole or a combustion bowl on top of the piston head (16) to improve the compression ratio. When the engine head is assembled on the engine new aluminium gasket is installed so that cylinders are sealed and water and oil conduits are sealed.

One of the embodiments is that the ignition system is installed to convert diesel engine to LNG engine after installing spark plug (18). Ignition system in spark ignition internal combustion engine generates a spark an electrode to a high temperature to ignite a fuel-air mixture. To install ignition kit diesel fuel pump is removed and according to number of cylinders distributor (22) is installed. A distributor (22) is an enclosed rotating shaft used in spark-ignition IC engine that have mechanically timed ignition. The main function of distributor is to supply high voltage from ignition coil (21) to the spark plug (18) installed in the cylinder according to the timing of the engine. The function of the ignition coil (21) is to convert 12 volt current to 25000-30000 volts and transfer the current to the distributor (22). The distributor (22) is distributing the current to the spark plugs (18) through plug wires.
One of the embodiments is to supply fuel to the engine a throttle body (12) is to be installed which will control the flow of the air-gas mixture to the engine (14). This process will control the flow of fuel to engine (14) and the acceleration of the vehicle. The throttle body (12) is fitted on the air intake of the engine (3). On throttle body (12) include butterfly valve (13) that can accelerate the engine. The air-gas mixture (11) is installed before the throttle body (12) that can get proper amount of mixture. The air is supplied from the air filter (not shown in figure) through the turbocharger (9). The function of air filter is to remove solid particles such as dust, pollen, mold, and bacteria from the air and supply clean air to the engine. A turbocharger (9) is a turbine-driven forced induction device that increases efficiency of IC engine. A turbocharger compresses the air and increases the temperature of air.

One of the embodiments is that the gas reducer (7) is installed after the 3-way L-port ball valve the gas reducer is different according to the power of the engine and size of the engines. Gas reducer controls the pressure required for supply of gas to engine. The reducer (7) is ideal for Carburetor where Sequential Gas Injection is not essential. It is two-stage reducers that reduces the LNG pressure and vaporize it allowing the regular flow of gas to the engine.

One of the embodiments is that LNG fuel system is installed after gas reducer (7) that contain LNG fuel tank (1). An LNG tank that is used to store cryogenic fuel as LNG. LNG is a cryogenic fuel means it has a temperature about -162 0C. The storage tank (1) is used to store LNG has materials that have extremely efficient insulation between the outer surface and inner surface of the tank. The storage tank will store and supply LNG to heat exchanger (2) which converts liquefied natural gas (LNG) to natural gas. A heat exchanger (2) is connected between LNG tank (1) and gas reducer (7) which supplies heat from one fluid to another fluid and finally converts the state of liquefied natural gas. Heat exchanger include one coil in which LNG flows into it and around the coil hot coolant circulates, the whole process occurs due to conduction. To convert the state of LNG, high temperature coolant is used which comes from the engine after cooing the engine (14). The coolant flows into radiator (15) that cools down the temperature and absorbs the heat from the engine and gets hot. High temperature coolant will pass around the coil in the heat exchanger (2) and low temperature LNG absorb the heat from the high temperature coolant and converted into gaseous state, same way the temperature of the coolant will be lowered by cryo-energy of LNG and it flows toward gas reducer and then radiator.

One of the embodiments is that Diesel engine when used for LNG, heats up more than while running on diesel. Cryo-energy from low temperature LNG (-150°C to -162°C) is utilized with precise cryo-thermal heat exchange engineering. LNG cryogenic tube heat-exchanger utilizes cryo-energy of LNG (-150°C to -162°C) to effectively & positively cool the coolant coming from the engine to ensure that additional heat generated by the engine while running on LNG is effectively, efficiently, economically, & positively syphoned away. Precise & positive heat exchanger ensures confirmed LNG re-gasification before supply to engine.

The present invention relates CNG cylinders (6) as a backup fuel. The CNG cylinders (6) are connected with the means of high-pressure SS (Stainless Steel) tubes and the gas leaving the heat exchanger (2) of the LNG fuel tank (1) is also connected with the means of high pressure SS (Stainless Steel) tubes. Both connections meet at a point where a 3-way L-port ball valve (5) is installed. The 3-way L-port ball valve (5) switched in two ways
a) Gas is supplied from CNG cylinders
b) Gas is supplied from the LNG tank.
Now to make the system safe by not allowing the high-pressure gas from the CNG cylinders (6) to the LNG line, we install two non-return valves (3) before the 3-way L-port ball valve (5) on LNG line and between the two non-return valves (3) a safety valve (4) is installed to ensure safety. At the outlet port of the 3-way L-port ball valve (5), the gas will be supplied to the gas reducer (7). That gas reducer (7) will regulate the flow of the gas and supply to the air-gas mixture (11) and to the engine intake manifold.