Title of Invention

"A GASEOUS FUEL INTERNAL COMBUSTION ENGINE"

Abstract

This invention relates to a gaseous fuel internal combustion engine, which is provided with (a) an Electronic Control Unit (ECU) (6), (b) an oxygen sensor (14) electrically connected to said ECU, (c) a stepper motor (27), (d) a pressure regulator (3) connected at one end to said stepper motor and at the other end to said ECU and provided with a high pressure solenoid valve (29) and a low pressure solenoid (28) and an idling means (30), (e) a gas-air mixer (4) adapted to receive air through air filter (5) and gas successively through gas pipe (31), said pressure regulator (3) and said stepper motor and comprising a cylindrical body (16), a mixer valve (17), annular venturi throat area (38), air inlet pipe (37), gas inlet pipe (36) and outlet port (39), (f) a magnetic sensor (9) connected to said ECU and fixed on a timing gear driven by a gear mounted on said crank shaft, (g) a throttle position sensor (13) fixed on said throttle valve, (h) combustion chamber (41) of trauncated conical shape with round corners at the bottom, (i) cylindrical head (33) having a semi-spherial cavity (40) around each spark plug (20), (j) an-exhaust cooler (21) connected to said exhaust manifold (24) and comprising a cooling chamber (25), inlet for coolant (22) and outlet for coolant (23) and an exhaust gas outlet (26), (K) engine has compression ratio of 10 to 13, (1) the cooling jacket has volume 15 to 30% more than the conventional diesel engine, (m) each of said spark plug (20) is provided-with a coil (10).

Full Text

FIELD OF INVENTION The present invention relates to a gaseous fuel internal combustion engine PRIOR ART In gaseous fuel engines, power developed by engine was approximately 10% lower as compared to liquid fuel engine of the same size The limitation in achieving similar power in gaseous engine was due to lesser volumetric efficiency In more precise way it can be said that because of gaseous fuel, energy density of stoichiometric mixture goes down about 10% However gaseous fuels are advantageous as these are cleaner burning fuels Gaseous fuels generate less noxious emission than liquid fuels and these can meet rigorous governmental regulations related with environmental pollution There have been recent developments in the gaseous fuel engine's noxious emission reduction strategies but these are mainly concentrated towards advance engine designs, e g engines with multipoint fuel injection system and other advance technology engines In contrast a gaseous fuel engine is simple and cheaper and is therefore favored in underdeveloped and developing countries A simple gaseous engine includes a pressurized fuel tank, a pressure regulator for reducing fuel from a high storage pressure to a lower working pressure (about one bar), a gas control valve, an air gas mixer at engine intake manifold and an engine management system for proper operation of engine Problem occurs in accurate mixing of gas with air at the gas air mixer The mixing of gas with air is sensitive to variation in pressure of suction manifold of gas air mixer, air temperature and pressure caused due to operation of engine and environmental conditions Opposite to this, gas flow rate has lesser fluctuations and is controlled by pressure regulation The variations in air and gas pressure result in improper homogenous mixing of gas with air The power produced by combustion of gaseous fuel varies widely depending on combustion chamber design, compression ratio, ignition timing etc. Engines are optimized for the type of fuel. Noxious emission is a function of combustion temperature and combustion duration. NOx emission is a health hazard for human beings. Governmental regulations over noxious emission are becoming increasingly stringent. Combustion time reduction has been achieved by some other models also but still there is considerable scope for reducing combustion time and peak temperature to get overall reduction in noxious emission. Therefore, it is needed to improve gas air mixing system through suitable gas air mixer and novel combustion chamber to minimize CO, NOx, Hydrocarbon emission and increased power achieved by gaseous engine working under wide working conditions, A compressed natural gas engine is disclosed in the art comprising one or more gas supplies, a pressure controller for controlling the pressure of the gas injected by the gas supply, a fuel rail for providing gas for the engine from said pressure controller, the fuel rail including a plurality of gas injection tubes fixed to the inner wall of the intake port of the cylinder head by fixing means, a fuel supply line for connecting the gas supply, the pressure controller and the fuel rail, an electronic control unit for outputting a control signal in order to inject a proper amount of the compressed natural gas into the engine and electrically connected with the gas injectors, so that fast burning of the injected gas in the combustion chamber is easily accomplished. One drawback of the compressed natural gas engine disclosed about is that it is complicated in construction and is therefore higher in the cost and can not be manufactured in the developing countries. Other drawback of the compressed natural gas engine disclosed above is that its maintenance is difficult due to lack of adequate infrastructure support for such engine. OBJECTS OF PRESENT INVENTION The main object of present invention is to propose a gaseous fuel internal combustion engine which is simple in construction. Another object of the present invention is to propose a gaseous fuel engine which is cheaper in cost. Yet another object of the present invention is to propose a gaseous fuel engine which functions on compressed natural gas as a gaseous fuel. Still another object of the present invention is to propose a gaseous fuel engine which produces less emission, more particularly less noxious emission. Further object of the present invention is to propose a gaseous fuel engine which is fuel efficient. Yet further object of the present invention is to propose a gaseous fuel engine which is easier to maintain. Further objects and advantages of the invention will be more apparent from the ensuring description when read in conjunction with the accompanying drawings. STATEMENT OF INVENTION According to this invention, there is provided a gaseous fuel internal combustion engine comprising a cylinder block assembly having a cylinder block, a cylinder head, the cylinder block having plurality of cylinders, each cylinder provided with a cylinder liner, a piston slidably fitted in each said cylinder liner, a cylinder head a crankshaft connected by plurality of connecting rods to said pistons, an inlet valve, an exhaust valve, a spark plug located in said cylinder head, a throttle valve, an accelerator paddle, an exhaust manifold, characterized in that the said gaseous fuel engine system is provided with: a) an Electronic Control Unit (ECU), b) an oxygen sensor electrically connected to said ECU, c) a stepper motor, d) a pressure regulator connected at one end to said stepper motor and at the other end to said ECU and provided with a high pressure solenoid valve and a low pressure solenoid and an idling means, e) a gas-air mixer adapted to receive air through air filter and gas successively through gas pipe, said pressure regulator and said stepper motor and comprising a cylindrical body, a mixer valve, annular venturi throat area, air inlet pipe, gas inlet pipe and outlet port, f) a magnetic sensor connected to said ECU and fixed on a timing gear driven by a gear mounted on said crank shaft, g) a throttle position sensor fixed on said throttle valve, h) combustion chamber of truncated conical shape with round corners at the bottom, j) cylindrical head having a semi-spherical cavity around each spark plug, k) an-exahust cooler connected to said exhaust manifold and comprising a cooling chamber, inlet for coolant and outlet for coolant and an exhaust gas outlet, 1) engine has compression ratio of 10 to 13 , m) the cooling jacket has volume 15 to 30% more than the conventional diesel engine, n) each of said spark plug is provided with a coil. DESCR1PTION OF FIGURES The invention will now be illustrated with accompanying drawings which are intended to illustrate an embodiment of the present invention These are not intended to be taken restrictively to imply any limitation as the scope of the present invention In the accompanying drawings Figure 1 shows the block diagram of the proposed gaseous engine Figure 2 shows the sectional view of a gas mixer Figure 3 shows a sectional view of a cylinder of the engine Figure 4 shows the isometric view of exhaust cooler Figure 5 shows a block diagram of pressure regulator DESCRIPTION OF INVENTION WITH REFERENCE TO DRAWINGS. Referring to fig 1, the proposed gaseous fuel internal combustion engine has a cylinder block assembly (1) and a gas-air mixer (4) for supplying gas and air mixture in the stoichiometric ratio to the engine The quality of the gas-air mixture is controlled by an electronic control unit (ECU) (6) An oxygen sensor (14) is electrically connected to said ECU (6), and senses percentage of oxygen in the exhaust gases and transmits the signal to said ECU which is turn gives signal to a stepper motor (27) to control leanness/richness of air fuel mixture in the said air-gas mixer to maintain the air-gas mixture in stoichiometirc ratio The said stepper motor (27) regulates the supply of gas to the said gas-air mixer (4) The said gas-air mixer gets air supply filtered through air filter (5) The gas-air mixture so produced goes to intake manifold (2) from where it enters the individual cylinder through inlet valve (18) (fig 3) In order to regulate the speed of the engine, position of the throttle (7) of the engine is changed by accelerator pedal (8) A throttle position sensor (13) sends signal to said ECU which is electrically connected to the said stepper motor (27). A gas pressure regulator (3) regulates the pressure of gas supplied to the said stepper motor (27). The gas supply to the said pressure regulator is through an gaspipe inlet (31). A magnetic sensor (9) senses the speed of the engine and communicates the signal to the said ECU (6). If speed goes higher than the pre-set value, the said ECU (6) reduces the gas supply through the said stepper motor (27). This reduces the engine speed within the pre-set limits. The engine is provided with a distributor-less ignition system. Each spark plug is provided with a coil (10), which receives the current from 12V battery (11) through said ECU at appropriate time to ignite the fuel air mixture in the cylinder. The preferable ignition time for the engine is 13° to 15°, more preferably 14° before Top Dead Centre (TDC) in compression stokes of each cylinder. In order to obtain better fuel efficiency, the valve opening and closing have been optimized. The inlet valve opens at 21° before TDC and closes at 59° after Bottom Dead Centre (BDC). The exhaust valve opens at 59° after BDC and closes at 21° after TDC. The engine has compression ratio of 10 to 13. A 12V battery (12) in combination with 12 V battery (11) is used for start of the engine. Referring to Fig. 2, the gas-air air mixture (4) consists of a cylindrical body (16) in which a mixer valve (17) is housed. The gas from said stepper motor (27) enters the said mixer valve (17) through an gas inlet pipe (36). The gas comes out from the annular Venturi throat area (38) and mixes with air entering from air inlet (37) connected to the said air filter (5). The homogenous gas air mixture in stoichiometric ratio leaves the said mixer valve through outlet port (39) which is connected to the throttle (7) of the engine. Referring to fig. 3, the proposed gaseous fuel engine has a cylinder block (34), a cylinder head (33), the said cylinder block having a plurality of cylinders with cylinder liners (35) A piston (32) moves upwardly and downwardly in each cylinder liner. An inlet valve (18) and exhaust valve (19) are located at predetermined position of cylinder head (33) and spark plug (20) is located near/the said inlet and exhaust valves. The intake and exhaust gas air mixture/burnt gases is opened and closed by the said inlet and exhaust valves respectively. A crankshaft (not shown) is provided to convert reciprocatory motion of the said piston into rotatory motion. The said crankshaft is connected through plurality of connecting rods to said piston (32). A timing gear (not shown) is driven by another gear mounted on the said crankshaft. The said magnetic sensor (9) also senses the rotational position of the timing gear and passes the signal to said ECU which accordingly regulates the ignition timing. The combustion chamber enclosed between crown of piston and cylinder head has a novel construction. The crown of piston has a cavity (41) which has a truncated conical shape with rounded corners at the bottom of the combustion chamber. The combustion chamber walls may also be rounded or may have helical groves. The gas air mixture entering the cylinder from inlet valve is guided by the shaped walls of combustion chamber which further mixes the gas air mixture by swirling action, directs the gases towards spark plug and push out burnt gases generated from the last stroke. Because of novel shape of combustion chamber, the gas air mixture entering the combustion chamber gets mixed with the burnt gases and reduce the inside temperature of combustion chamber thereby bringing down the NOx formation. The cylinder head has a semi-spherical cavity (40) around spark plug location, which reduces NOx emissions. Referring to fig. 4, the exhaust gases leave the cylinder through the said exhaust valve and enter the exhaust cooler (21) through exhaust manifold (24). The said exhauster cooler comprises a cooling chamber (25) connected to the said exhaust manifold (24) having an inlet (22) and outlet (23) for the coolant and an exhaust gas outlet (26) for exhaust of cooled gases after being cooled by the said exhaust cooler (21). Another novel feature of engine lies in the cooling provided in the cylinder block and cylinder head. An important differentiating feature of the cooling water jacket of the present engine is that volume of jacket is 15 to 30% higher than volume of coolant jacket in a conventional diesel engine. This is achieved by innovative lay-out of coolant channel. This higher volume of coolant enhances the cooling of engine which helps in reducing the NOx formation. The exhaust gases are further treated by a catalytic converter (not shown) and exhausted in the air through exhaust muffler (not shown). Referring to the fig. 5, the pressure regulator (3) is provided with a high pressure solenoid valve (29) for inlet of the gas into the regulator and a low pressure solenoid valve (29) for inlet of the gas into the regulator and a low pressure solenoid (28) for controlling gas supply to the next pressure regulator comprises two to three pressure reduction stages so that gas from cylinder at high pressure is reduced to a pressure before entry into the said air-gas mixer (4). An idling nut (30) is provided to facilitate supply of gas for idling of the engine. The nut is set manually to tune the engine for idling. It is to be understood that the gaseous fuel engine of the present invention is vulnerable to modifications, changes, adaptations by those skilled in the art. Such variant embodiments are intended to be within the scope of the present invention, which is further set forth under the claims that follow. I CLAIM 1. A gaseous fuel internal combustion engine comprising a cylinder block assembly (1) having a cylinder block (34), a cylinder head (33), the cylinder block having plurality of cylinders, each cylinder provided with a cylinder liner (35), a piston (32) slidably fitted in each said cylinder liner, a cylinder head (33) a crankshaft connected by plurality of connecting rods to said pistons, an inlet valve (18), an exhaust valve (19), a spark plug (20) located in said cylinder head, a throttle valve (7), an accelerator paddle (8), an exhaust manifold (24), characterized in that the said gaseous fuel engine system is provided with: (a) an Electronic Control Unit (ECU) (6), b) an oxygen sensor (14) electrically connected to said ECU, c) a stepper motor (27), d) a pressure regulator (3) connected at one end to said stepper motor and at the other end to said ECU and provided with a high pressure solenoid valve (29) and a low pressure solenoid (28) and an idling means (30) e) a gas-air mixer (4) adapted to receive air through air filter (5) and gas successively through gas pipe (31), said pressure regulator (3) and said stepper motor and comprising a cylindrical body (16), a mixer valve (17), annular venturi throat area (38), air inlet pipe (37), gas inlet pipe (36) and outlet port (39) f) a magnetic sensor (9) connected to said ECU and fixed on a timing gear driven by a gear mounted on said crank shaft, g) a throttle position sensor (13) fixed on said throttle valve, h) combustion chamber (41) of truncated conical shape with round corners at the bottom, j) cylindrical head (33) having a semi-spherical cavity (40) around each spark plug (201 an-exhaust cooler (21) connected to said exhaust manifold (24) and comprising a cooling chamber (25), inlet for coolant (22) and outlet for coolant (23) and an exhaust gas outlet (26), engine has compression ratio of 10 to 13, the cooling jacket has volume 15 to 30% more than the conventional diesel engine, each of said spark plug (20) is provided with a coil (10). A gaseous fuel internal combustion engine as claimed in claim 1, wherein the said combustion chamber (41) has rounded walls. A gaseous fuel internal combustion engine as claimed in claim 1, wherein the said combustion chamber (41) has helical grooves on the walls. A gaseous fuel internal combustion engine substantially as herein described and illustrated with accompanying drawing.

Documents:

1139-del-2003-abstract.pdf

1139-del-2003-claims.pdf

1139-del-2003-complete specification (granted).pdf

1139-del-2003-correspondence-others.pdf

1139-del-2003-correspondence-po.pdf

1139-del-2003-description (complete).pdf

1139-del-2003-drawings.pdf

1139-del-2003-form-1.pdf

1139-del-2003-form-19.pdf

1139-del-2003-form-2.pdf

1139-del-2003-form-3.pdf

1139-del-2003-form-5.pdf

1139-del-2003-pa.pdf