Title of Invention

"AIR INTAKE DEVICE FOR 4-STROKE MULTI-VALVE SPARK IGNITION ENGINE"

Abstract

The secondary intake throttle valve device comprising an additional throttling device (secondary throttle) in one of the engine intake valve duct in a multi intake valve engine. The secondary throttle valve and main throttle valve are coupled to the main throttle valve actuating system by a mechanical linkage or through a pneumatic linkage. The intake duct fitted with the additional secondary throttle valve is normally closed at idling and at low loads and gets opened by its mechanical or pneumatic linkage at a predefined position. At part load intake air is inducted through one valve instead of two or more intake valves in to the engine thus generating a higher amount of swirl leading to faster combustion and better combustion efficiency. At higher load all the intake valves are open thus there is no sacrifice for power output and volumetric efficiency.

Full Text

AIR INTAKE DEVICE FOR 4-STROKE MULTI VALVE SPARK IGNITION ENGINE Field of the invention The present invention relates to an air intake system for a multi-intake valve 4-stroke spark ignition engine. More particularly, the present invention relates to a secondary throttle intake for a 4-stroke multi valve single or multi cylinder spark ignition engine used for two-wheeled vehicle applications. Background of the invention It is known in the art that engine performance of four stroke engines are influenced by the number of valves per cylinder, the valve opening area, the valve timings and the geometry of the intake and exhaust ports. The present trend in use four stroke engines to obtain more power form a given swept volume of an engine is to introduce multivalves for the intake and exhaust system. Variable speed automobile engines work over a wide speed range. Conventional engine systems are tuned around the speed corresponding to maximum torque or power in the system. In such systems, the part load fuel econorny, emission and throttle response are compromised. For example, when the engine is tuned for, good part load fuel economy, by compromising on the peak torque, the drivabilitiy of the vehicle is compromised. Work is underway to improve variable valve timing systems in order to achieve optimum engine performance in the engine operating range. However, such systems that have been developed in the art are complicated and not commercially available. Work has also been done on intake induction device to improve the torque over a wide speed range. US Patent 4,232,640 discloses an induction system for an internal combustion engine with variable induction volume chambers where the auxiliary induction passage is comparatively smaller in cross section than the main induction passage. Two inlet passages are arrayed in parallel, requiring a large space and are connected to same duct leading to intake valve. US Patent 4,862,840 discloses an intake device for internal combustion engine comprising a high speed intake passage and a low speed intake passage for high-speed operation range and low speed operation range respectively of the engine. Separate control valves are provided in each of the intake passages to control the flow passage areas. An intake box is connected to the upstream ends of both the high speed and the low speed intake passage with a throttle valve provided therein which is operable in response to the driver instructions. US Patent 5,937,815 discloses an air intake system for internal combustion engines where air inlet path comprises a double structure of the main inlet path and sub inlet path and sub inlet path is placed in close contact with a bottom wall of main inlet path. The airflow is switched between the two passages depending on operating load and speed range. As claimed, it has improved the torque characteristics at the entire speed range. The above-mentioned prior art however suffer from several disadvantages such as that the amount of air intake at high engine is insufficient to obtain a full power. There is also a possibility that an abrupt change in torque characteristics may occur while switching between high and low speed operation. Objects of the invention It is an object of the invention to develop a system in a multi-intake valve engine, which increases the intake air amount over a wide range of engine speed. It is another object of the invention to develop a system in a multi-intake valve engine capable of improving the combustion by positively generating the tumble/swirl even at low engine speeds. It is another object of the invention to provide an internal combustion engine, using multi intake valves for better torque and power characteristics and containing a system for improving the combustion by positively generating the tumble / swirl even at low engine speeds and loads. Another object of the invention is to provide an improved throttle arrangement, with main throttle valve and secondary throttle valve where the secondary throttle valve does not obstruct the passage for air induction in full open condition. Summary of the invention The above and other objects of the present invention are achieved by the secondary throttle system of the invention wherein the engine operates with one intake valve closed at low loads and partially open at mid-loads thereby enabling better thermal efficiency, smoother combustion and low emission. Accordingly, the present invention provides an air intake device for a multi intake valve per cylinder of a single or multi -cylinder, spark ignited internal combustion engine, said multi intake valve having independent inlet passages leading to each valve, said air intake device comprising a main passage means provided connected at one end thereof to an air box of said engine, a main throttle valve provided in said main passage means and connected to a first actuation means, said main passage means being connected at the other end thereof to two or more independent inlet means, a secondary throttle valve operatively associated with said main throttle valve, and connected to a second actuation means, said two or more independent inlet means being connected at the end opposite the main passage means to the combustion chamber of said internal combustion engine, said secondary throttle being closed at low fuel loads and partially open at mid-load and fully open at high fuel load. In one embodiment of the invention, the secondary throttle valve is pneumatically coupled to the said main throttle valve. In one embodiment of the invention, the secondary throttle valve is mechanically coupled to the said main throttle valve. In another embodiment of the invention, the secondary throttle valve is provided in one of said independent inlet means. In another embodiment of the invention, the secondary throttle valve is provided in the extension housing of said two or more independent inlet means. In another embodiment of the invention, the secondary throttle valve is provided in the cylinder head of said engine. In another embodiment of the invention, the air intake device is provided with a bracket means coupled to the main body of the engine, a stopper means being connected to the secondary throttle valve through the bracket means, said secondary throttle valve being provided with retention means to retain the secondary throttle valve in a closed position. In a further embodiment of the invention, the retention means comprises a helical spring. In yet another embodiment of the invention, the stopper means comprises a pin connected to the secondary throttle valve through an aperture provided in the said bracket means. In another embodiment of the invention, the bracket means is coupled to the engine body through an 'O' ring. In another embodiment of the invention, the secondary throttle valve is connected to and responsive to a movement generating means through the stopper means, said movement generating means being provided with a position retention means. In a further embodiment of the invention, the movement generating means comprises a disc and the position retention means comprises a secondary throttle valve adjusting screw provided on the said movement generating means. In another embodiment of the invention, the secondary throttle valve is connected to said second actuation means provided with a pressure exerting means passing through the movement generating means and connected to the main throttle valve. In a further embodiment of the invention, the pressure exerting means comprises a cable. In another embodiment of the invention, the pressure exerting means is provided with a clamping means at one end thereof adjacent to the movement generating means at a predefined distance. In another embodiment of the invention, the clamping means is free floating in aperture provided in the movement generating means. In a further embodiment of the invention, the secondary throttle valve is connected to a display means whereby the position of the secondary throttle valve is indicated. In another embodiment of the invention, the secondary throttle valve is selected from the group consisting of a rotary valve, sliding valve and a butterfly type valve. In yet another embodiment of the invention, the main throttle valve is the carburetor valve. In a further embodiment of the invention, the display means comprise light emitting diodes or electrical bulbs. The present invention also relates to an internal combustion engine of the four stroke multi-valve per cylinder single or multi cylinder spark ignition type, said engine comprising an air intake device provided therein, said air intake device comprising said multi intake valve having independent inlet passages leading to each valve, said air intake device comprising a main passage means provided connected at one end thereof to an air box of said engine, a main throttle valve provided in said main passage means and connected to a first actuation means, said main passage means being connected at the other end thereof to two or more independent inlet means, a secondary throttle valve operatively associated with said main throttle valve, and connected to a second actuation means, said two or more independent inlet means being connected at the end opposite the main passage means to the combustion chamber of said internal combustion engine, said secondary throttle being closed at low fuel loads and partially open at mid-load and fully open at high fuel load. Brief description of the accompanying drawings Figure 1 is an exploded view of secondary throttle valve of the rotary type. Figure 2 is an exploded view of secondary throttle valve of the Butterfly Type Figure 3 is a schematic representation of a four stroke, multi intake valve engine with rotary type secondary throttle valve means. Figure 4 is a schematic representation of a four stroke, multi intake valve engine with butterfly type secondary throttle valve. Figure 5 is a graph showing the fuel consumption characteristics at road load. Detailed Description of the invention In the present invention, the airflow to the engine is through two different independent intake ports/ ducts and valves per cylinder in a four-stroke multi valve engine. Towards upstream side, both these passages are connected to the air box through main passage and where the main throttle valve is fitted. At the low throttle opening of the main throttle valve, the secondary throttle valve is closed and partially opens at mid-load range and allows air to be inducted inside the combustion chamber through one valve, relatively at a higher velocity and swirl. This permits the establishment of high turbulence in the chamber at the time of combustion to improve the flame propagation and combustion, thus improving fuel consumption and lowering the emission. This is accomplished without the sacrifice of power output and volumetric efficiency due to the use of two inlet valves for air induction. In the present invention, the intake air amount is increased over a wider operating range. At low load, the inlet duct is closed since the secondary throttle does not operate. At part load, where the air intake required is small, this is achieved due to the higher intake velocity/inertia supercharging due to the closing of one inlet valve duct in the multi intake valve engine. This also increases the tumble/swirl thereby improving the combustion. At full load, all the inlet valves are open thereby achieving higher combustion and higher intake of air. The engine operates with one intake valve closed at low fuel loads and partially open at mid-loads thereby ensuring better thermal efficiency, smoother combustion, and low emissions. At higher loads and speeds, all the intake valve ducts are open thereby ensuring better drivability and pick up of the engine. The invention will now be explained with reference to the drawings accompanying the specification where Figure 1 is an exploded view of the secondary throttle valve of the rotary type. Figure 2 shows the use of a butterfly type valve for the secondary throttle valve in place of a rotary valve. The air intake device comprises of a primary throttle (12) and a secondary throttle (1). The secondary throttle (1) is provided in an intake port or in the intake port extension body of the engine (not shown) after the main throttle (12). The main throttle can be the carburetor throttle. The secondary throttle is constructed such that when fully open, the air flow is not obstructed thereby enabling smooth air passage. A bracket (6) is provided connected to the body (3) by means of an 'O' ring (2). A stopper pin (4) is screwed on to the secondary throttle (1) through a slit in the bracket (6). The secondary throttle (1) is retained in the closed position at very low loads of fuel by means of a helical spring (5). At mid-loads or high loads, the secondary throttle (1) is rotated by means of the stopper pin (4) which is pushed by a disc (7) provided on the bracket (6). The position of the secondary throttle is adjusted in operation by means of a secondary throttle adjusting screw (8) provided on the disc (7). The secondary throttle (1) is actuated by an actuation means (11) which comprises inter alia a cable (10) which passes through the disc (7) and is connected to the main throttle (12). The inner cable (10) passing through the disc (7) is provided with a clamp (9) at a predefined distance. When the inner cable (10) is actuated through the throttle actuation means (11), the clamp (9) moves freely inside the slot provided on the disc (7). The free travel of the clamp (9) inside the disc corresponds to the movement of the throttle (1) under part fuel load condition. The clamp (9) rotates the disc (7) thereby rotating the secondary throttle (1) corresponding to predetermined position of the main throttle (12). Thus the amount of air intake during part fuel load conditions is regulated. At the throttle wide open position, the main throttle and the secondary throttle are both fully open. The secondary throttle is operated through either mechanical connection with the main throttle or through pneumatic pressure actuated by the vacuum in the intake manifold. The exact position of the secondary throttle is displayed on the instrument panel through conventional indication means such as light emitting diodes or electrical bulbs. Figures 3 and 4 show schematic representations of the air intake device with a rotary type valve and a butterfly type valve respectively as the secondary throttle valve, and the interconnections between the air intake device of the invention and the engine. The internal combustion engine includes a cylinder block (16) with a plurality of cylinder bores (17). The piston (15) slides between the bores (17) and delivers power to the crankshaft (not shown) through general arrangements of connecting rod. The cylinder head (18) is fixed to cylinder bore (17) with a plurality of combustion chambers (19). The piston (15), cylinder bore (17) and combustion chamber (19) provide a variable volume in the combustion chamber where the combustion occurs. The spark plug (21) is positioned inside the combustion chamber to ignite the combustible mixture in a known manner. When the exhaust valve (14) opens, exhaust gases are expelled in to the atmosphere through the exhaust passage (20). The multi intake passage (22) and (23) per cylinder are connected to the combustion chamber through inlet valves (13) of the respective cylinder in a known manner for delivering the air fuel charge to respective combustion chambers (19). Referring now specifically to figure 3, the secondary throttle valve (1- of the rotary type, la - butterfly type) is provided in one of the intake ports or intake port extension body (3) downstream of the main throttle valve (12). The main throttle valve may be a carburetor throttle (12). The secondary throttle valve (1, la) is constructed such that when it is fully open it does not obstruct the airflow and provides a smooth air passage. The secondary throttle valve (la) can be of a butterfly type as shown in figure 4 and is connected to the main throttle valve with a suitable mechanism fulfilling the criterion that at low load secondary throttle valve (la) remains closed and partially open at pre-defined position, as explained above The secondary throttle valve (1) can be operated through the pneumatic mechanism actuated by the vacuum in the intake manifold. At idling and low loads, when the secondary throttle valve (1) (la) is closed, the air or air fuel mixture is inducted into the combustion chamber through one valve instead of two or more intake valves in to the combustion chamber, relatively at a higher velocity and swirl. This permits the establishment of high turbulence in the chamber at the time of combustion to improve the flame propagation and combustion, thus improving the fuel consumption and lowering the emission. This is accomplished without the sacrifice of power output and volumetric efficiency due to the use of two inlet valves for air induction. In Figure 5 curve 'A' shows the brake specific fuel consumption without the air intake device of the invention and curve 13' with the air intake device of the invention device in operation. With the said device, lower specific fuel consumption at low loads/road load condition has been achieved. Position of the secondary throttle valve (1) can be displayed on the instrument panel through light emitting diodes or electrical bulbs. We claim: 1. An air intake device for a multi-intake valve per cylinder of a single or multi-cylinder, spark ignited engine, said multi-intake valve having independent inlet passages leading to each valve, said air intake device comprising a main passage means provided connected at one end thereof to an air box (24) of said engine, a main throttle valve (12) provided in said main passage means (3) and connected to a first actuation means, said main passage means (3) being connected at the other end thereof to two or more independent inlet means (22, 23), a secondary throttle valve (1) operatively associated with the said main throttle valve (12), and connected to a second actuation means (11) two or more independent inlet means (22, 23) being connected at the end opposite the main passage means (3) to the combustion chamber of said internal combustion engine, said secondary throttle valve (1) being closed at low fuel loads and partially open at mid-load and fully open at high fuel load. 2. An air intake device as claimed in claim 1 wherein the secondary throttle (1) neumatically coupled to the said primary throttle valve (12) 3. An air intake device as claimed in claim 1 wherein the secondary throttle valve (1) is mechanically coupled to the said main throttle valve (12). 4. An air intake device as claimed in claim 1 wherein the secondary throttle valve (1) is provided in a cylinder head (18) of said engine. 5. An air intake device as claimed in claim 1 wherein the secondary throttle valve (1) is provided in one of said independent inlet means (22). 6. An air intake device as claimed in claim 1 wherein the secondary throttle valve (1) is provided in the extension housing of said two or more independent inlet means (22, 23). 7. An air intake device as claimed in claim 1 wherein the air intake device is provided with a bracket means (6) coupled to the mam body of the engine, a stopper means (4) being connected to the secondary throttle valve (1) through the bracket means (6), said secondary throttle valve (1) being provided with retention means (5) to retain the secondary throttle valve 91) in a closed position. 8. An air intake device as claimed in claim Vwherein the retention means (5) comprises a helical spring. 9. An air intake device as claimed in claim 7 wherein the stopper means (4) comprises a pin connected to the secondary throttle valve (1) through an aperture provided in the said bracket means (6). 10. An air intake device as claimed in claim 7 wherein the bracket means (6) is coupled to the engine body through an 'O' ring (2). 11. An air intake device as claimed in claim 7 to 10 wherein the secondary throttle valve (1) is connected to and responsive to a movement generating means (7) through the stopper means (4), said movement generating means (7) being provided with a position retention means (8). 12. An air intake device as claimed in claim 11 wherein the movement generating means (7) comprises a disc (7) and the position retention means comprises a secondary throttle adjusting screw (8) provided on the said movement generating means (7). 13. An air intake device as claimed in claim 7 to 12 wherein the secondary throttle valve (1) is connected to a throttle actuation means (11), which is provided with a pressure exerting means (10) passing through the movement generating means (7) and connected to the main throttle (12). 14. An air intake device as claimed in claim 13 wherein the pressure exerting means comprises a cable (10). 15. An air intake device as claimed in claim 13 and 14 wherein the pressure exerting means (10) is provided with a clamping means (9) at one end thereof adjacent to the movement generating means (7) at a predefined distance. 16. An air intake device as claimed in claim 15 wherein the clamping means (9) is tree floating in an aperture provided in the movement generating means (7). 17. An air intake device as claimed in any preceding claim wherein the secondary throttle valve (1) is connected to a display means whereby the position of the secondary throtde valve (1) is indicated. 18. An air intake device as claimed in any preceding claim wherein the secondary throtdc valve (1) is selected from the group consisting of a rotary valve, a sliding valve and a butterfly type valve. 19. An air intake device as claimed in any preceding claim wherein the main throttle valve (12) is the carburetor valve. 20. An air intake device as claimed in claim 17 wherein the display means comprises light emitting diodes or electrical bulbs. 21. An air intake device as claimed in any preceding claim wherein the both the mam passage means (3) and two or more independent inlets (22, 23) are connected to the air box (214) through the main throttle valve (12) or carburetor. 22. An internal combustion engine of the four stroke multi-valve per cylinder single or multi-cylinder spark ignition type, whenever incorporating the air intake device of any preceding claim. 23. An air intake device substantially as described hereinbefore and with reference to the accompanying drawings. 24. An internal combustion engine substantially as described hereinbefore and with reference to the accompanying drawings.

Documents:

437-del-2002-abstract.pdf

437-DEL-2002-Claims-(19-11-2008).pdf

437-del-2002-claims.pdf

437-DEL-2002-Correspondence-Others-(19-11-2008).pdf

437-del-2002-correspondence-others.pdf

437-del-2002-correspondence-po.pdf

437-del-2002-drawings.pdf

437-del-2002-form-1.pdf

437-del-2002-form-18.pdf

437-del-2002-form-2.pdf

437-del-2002-form-3.pdf

437-del-2002-gpa.pdf

437-del-2002-petition-others.pdf