Title of Invention

"FOUR STROKE INTERNAL COMBUSTION ENGINE WITH IMPROVED FAST BURN"

Abstract

A four stroke internal combustion engine with improved fast burn being provided with a cylinder head, a cylinder block (2) integrally formed into a fore portion of a crankcase, a piston (1) slideably arranged in the said cylinder block (2) coupled to the crankshaft through a connecting rod (15), a combustion chamber (5a) being defined by the inner surface of the said cylinder head (5) and the wall of the said cylinder block (2), an exhaust port (11) connected to the said combustion chamber (5a) through an exhaust valve (3), an intake port (10) connected to the said combustion chamber (5a) through an inlet valve (4), an air intake device comprising an intake port (10) provided in the said cylinder head (5), wherein said intake port (10) communicating at one end with an inlet for the air or air-fuel charge and at the other end with the said combustion chamber (5a), said intake port (10) being divided into two arrayed helical shaped intake passages (10a, 10b) by a helical shaped port divider (8) provided therein and extending from one end of the said intake port (10) to the other end in the interior of the said intake port (10).

Full Text

Field of the invention: The present invention relates to a four stroke internal combustion engine with improved fast burn. More particularly, the present invention relates to an air intake device comprising helical shaped port divider to introduce high swirl even at low speeds and engine loads, thereby enabling better thermal efficiency, smoother combustion and low emission in a four stroke internal combustion engine. Background of the invention It is known in the art that the fast burn combustion process in internal combustion engines produces a more repeatable combustion pattern and provides for lesser emissions and better fuel efficiency. Several methods are known in the art for improving fast burn efficiency. These include alterations of the shape of the cylinder head, piston crown shape, number of valves, intake port, spark plug location and the like. In order to develop a fast burn combustion process, swirl squish and the tumble generated during the intake process along with the shape of the combustion chamber play an important role. The swirl generated during an induction process results in higher turbulence in the unburned mixture at the time of combustion inside the chamber during the combustion process which in turn increases the burn rate thereby providing better fuel efficiency and faster burn. It is known in the art that swirl can be generated during the intake process by suitable change in the design of the intake port, valve or combustion chamber. 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. The valves control the proportion of air flow to the chamber through the respective passages thereby ensuring that low and medium charge requirements are met primarily by the auxiliary induction passage. This results in improvement in the turbulence of the unburned mixture at the time of combustion. Japanese Laid Open Patent Publication No. 57-110675 discloses an air intake device with two alternate arrangements. In one arrangement, the low and high speed intake passages are individually connected to mutually independent intake chambers. In another arrangement, the low speed passage and a high-speed intake passage with an on/off valve are connected to a common intake chamber. In the first arrangement, the engine can produce a higher power output in a high speed operation range and a high torque in a low speed operation range. However, the idling is unstable and engine response may be lowered when quick acceleration is desired from /idling since during idling, both the chambers communicate with an intake valve hole and volume communicating with the intake valve hole is large. US Patent 4,862,840 discloses an air intake device for internal combustion engines comprising a high speed intake passage for high speed operation range and a low speed intake passage for low speed operation range respectively. In this disclosure, separate control valves are provided in each intake passage to control flow passage areas. An intake box is connected to upstream ends of both high and low speed intake passages. A throttle valve is provided therein operable in response to driver instructions. The above disclosures focus on the modification of the air intake passage by dividing the passage and arraying them in parallel. Flow is regulated through a valve in order to improve the swirl. The devices of the prior art discussed above require large spaces and linkage mechanisms in order to operate the valves. Objects of the invention It is accordingly an object of the invention to develop a system in an internal combustion 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 for an internal combustion engine that improves the combustion by positively generating the tumble/swirl even at low engine speeds. It is further object of the invention to develop a system in an internal combustion engine that improves the combustion by positively generating the tumble/swirl even at low engine loads. Summary of the invention The above and other objects of the present invention are achieved by a four stroke internal combustion engine with improved fast burn being provided with a cylinder head, a cylinder block integrally formed into a fore portion of a crankcase, a piston slideably arranged in the said cylinder block coupled to the crankshaft through a connecting rod, a combustion chamber being defined by the inner surface of the said cylinder head and the wall of the said cylinder block, an exhaust port connected to the said combustion chamber through an exhaust valve, an intake port connected to the said combustion chamber through an inlet valve, characterized in that an air intake device comprising an intake port provided in the said cylinder head, wherein said intake port communicating at one end with an inlet for the air or air-fuel charge and at the other end with the said combustion chamber, said intake port being divided into two arrayed helical shaped intake passages by a helical shaped port divider provided therein and extending from one end of the said intake port to the other end in the interior of the said intake port. The invention also relates to an air intake device where an intake helical port divider is provided in the intake port of an internal combustion engine. This imparts angular motion to the incoming air or air-fuel charge. The intake flow passage is divided into two arrayed helical passages. The helical flow divider enables the induction of air or the air-fuel charge in a tangential manner to impart angular velocity to the flow before it enters the engine cylinder. The air intake device of the invention is used in conjunction with a bath tub type combustion chamber to introduce high swirl even at low 'speeds and engine loads, thereby enabling better thermal efficiency, smoother combustion and low emission. Accordingly, the present invention provides an air intake device for an internal combustion engine, said air intake device comprising of an intake port provided in the cylinder head of the internal combustion engine, said intake port communicating at one end with an inlet for the air or air-fuel charge and at the other end with a combustion chamber of the engine, said intake port being divided into two arrayed helical shaped intake passages by a helical shaped port divider provided therein and extending from one end of the intake port to the other end in the interior of the intake port. In one embodiment of the invention, the air intake device of the invention is formed integral with the cylinder head of the internal combustion engine. In another embodiment of the invention, the air intake device of the invention is removably connected to the cylinder head of the internal combustion engine. In yet another embodiment of the invention, the helical shaped divider terminates at the exit of the intake port such that the air is inducted into the combustion chamber (5a) in a tangential manner. The invention also relates to a four stroke internal combustion engine with improved fast burn, comprising essentially of a cylinder head and a cylinder block integrally formed into a fore portion of a crankcase, a bore piston slideably inserted in the cylinder block and coupled to the crankshaft through a connecting rod, the inner surface of the cylinder head and the wall of the cylinder block forming a combustion chamber, an exhaust valve connected to the front portion of the cylinder head through an exhaust port and an inlet valve connected to the rear portion of the cylinder head through an intake port, both the inlet and exhaust valves opening into the combustion chamber, the cylinder head being provided with an intake port, said intake port communicating at one end with an inlet for the air or air-fuel charge and at the other end with a combustion chamber of the engine, said intake port being divided into two arrayed helical shaped intake passages by a helical shaped port divider provided therein and extending from one end of the intake port to the other end in the interior of the intake port.. In one embodiment of the invention, the inlet valve and the exhaust valve open and close through a cam shaft provided with an inlet cam and exhaust cam respectively. In one embodiment of the invention, the air intake device of the invention is formed integral with the cylinder head of the internal combustion engine. In another embodiment of the invention, the air intake device of the invention is removably connected to the cylinder head of the internal combustion engine. In another embodiment of the invention, a carburetor is connected to the intake port through a carburetor insulator/intake extension pipe at one end and with an air filter at the other end thereof. In a further embodiment of the invention, an air filter box is connected to the intake port through an intake extension pipe, a throttle valve being provided between the intake extension pipe and the air filter box in order to regulate air flow. In yet another embodiment of the invention, the helical shaped divider terminates at the exit of the intake port such that the air is inducted into the combustion chamber (5a) in a tangential manner. Brief description of the accompanying drawings Figure I is a cross - sectional view of an air intake device of the invention for an internal combustion engine with a carburetor for air fuel induction. Figure II is a cross - sectional view of an air intake device of the invention or a fuel injector type internal combustion engine. Detailed description of the invention In the air intake device of the invention, an intake helical port divider is provided in the intake port of an internal combustion engine. This imparts angular motion to the incoming air or air-fuel charge. The intake flow passage is divided into two arrayed helical passages. The helical flow divider enables the induction of air or the air-fuel charge in a tangential manner to impart angular velocity to the flow before it enters the engine cylinder. The air intake device of the invention is used in conjunction with a bath tub type combustion chamber to introduce high swirl even at low speeds and engine loads, thereby enabling better thermal efficiency, smoother combustion and low emission. The invention will now be described with reference to the accompanying figures which are exemplary and should not be construed as limiting the scope of the invention in any manner. The air intake device of the invention is applicable both in an internal combustion engine having a carburetor for air fuel induction (as shown in Figure 1) and in an internal combustion engine having a fuel injector for fuel induction (as shown in Figure 2). Figures 1 and 2 both show a four-stroke spark ignition engine where the cylinder head (5) and the cylinder block (2) are integrally formed into a fore portion of a crankcase (not shown). A bore piston (1) is slideably inserted in the cylinder block (2) and coupled to the crankshaft (not shown) through a connecting rod (15). The inner surface of the cylinder head (5) and the wall of the cylinder block (2) form a combustion chamber (5a) into which an inlet valve (4) and an exhaust valve (3) open. The exhaust valve (3) is connected to the front portion of the cylinder head (5) through an exhaust port (11). The inlet valve (4) is connected to the rear portion of the cylinder head (5) through an intake port (10). Both the inlet valve (4) and the exhaust valve (3) open and close through a cam shaft (7), which is provided with an inlet cam and exhaust cam. Referring now to Figure 1, which depicts a carbureted engine, a carburetor (9) is connected to the intake port (10) through an carburetor insulator/intake extension pipe (13). An air filter (not shown) is also connected to the carburetor (9). Referring now to Figure 2, which depicts a fuel injection type of engine, the air filter box (not shown) is connected to the intake port (10) through an intake extension pipe (13). A throttle valve (14) is provided between the intake extension pipe (13) and the air filter box in order to regulate the air flow. In both the embodiments of Figures 1 and 2, the intake port (10) comprises of a helical shaped port divider (8) which divides the intake port (10) into two arrayed intake ports (10a and 10b). The helical shaped divider terminates at the exit of the port such that the air is inducted into the combustion chamber (5a) in a tangential manner. The piston slides downwards during the suction stroke. The intake valve opens and air flows into the combustion chamber (5a) and cylinder block (2) after passing through a air filter, carburetor (9), carburetor insulator (13) and intake port (10). The air intake or air fuel charge gathers an angular velocity while passing through the intake port due to the presence of the helical port divider (8) which divides the intake port (10) into two helical arrayed intake passages (10a and 10b). The air or air-fuel charge with an angular velocity is expelled from the intake port in a tangential manner into the combustion chamber (5a). This results in high swirl and turbulence even at low speeds and loads. The high swirl results in an improvement in the flame burning velocity, reduces the combustion cycle variations thereby lowering emissions and improving the engine fuel efficiency. It is a further feature of the invention, that the helical divider in the intake port can be applied for both the fuel injection type or the carburetor type internal combustion engine. Another significant advantage of the invention is that the port divider can be integral with the cylinder head or can be inserted separately. WE CLAIM: 1. A four stroke internal combustion engine with improved fast burn being provided with a cylinder head, a cylinder block (2) integrally formed into a fore portion of a crankcase, a piston (1) slideably arranged in the said cylinder block (2) coupled to the crankshaft through a connecting rod (15), a combustion chamber (5a) being defined by the inner surface of the said cylinder head (5) and the wall of the said cylinder block (2), an exhaust port (11) connected to the said combustion chamber (5a) through an exhaust valve (3), an intake port (10) connected to the said combustion chamber (5a) through an inlet valve (4), characterized in that an air intake device comprising an intake port (10) provided in the said cylinder head (5), wherein said intake port (10) communicating at one end with an inlet for the air or air-fuel charge and at the other end with the said combustion chamber (5a), said intake port (10) being divided into two arrayed helical shaped intake passages (10a, 10b) by a helical shaped port divider (8) provided therein and extending from one end of the said intake port (10) to the other end in the interior of the said intake port (10). 2. The four stroke internal combustion engine as claimed in claim 1, wherein the said inlet valve (4) and the said exhaust valve (3) open and close through a cam shaft (7) provided with an inlet cam and exhaust cam respectively. 3. The four stroke internal combustion engine as claimed in claim 1, wherein the said intake device is integrally formed with the said cylinder head (5). 4. The four stroke internal combustion engine as claimed in claim 1 , wherein the said intake device is removably connected to the said cylinder head (5). 5. The four stroke internal combustion engine as claimed in any of the preceding claims 1 to 4, wherein the said intake port (10) is connected to a carburetor (9) through a carburetor insulator/intake extension pipe (13) at one end and with an air filter at the other end thereof. 6. The four stroke internal combustion engine as claimed in any of the preceding claims 1 to 4, wherein the said intake port (10) is connected to an air filter box through an intake extension pipe (13), a throttle valve (14) being provided between the said intake extension pipe (13) and the said air filter box in order to regulate air flow. 7. The four stroke internal combustion engine as claimed in any of the preceding claims 1 to 6, wherein the said helical shaped port divider (8) terminates at the exit of the said intake port (10) such that the air is inducted into the said combustion chamber (5a) in a tangential manner. 8. The four stroke internal combustion engine as claimed in any of the preceding claims 1 to 7, wherein both the inlet (3) and exhaust valves (4) open into the said combustion chamber (5a).

Documents:

1082-DEL-2002-Abstract-(09-06-2011).pdf

1082-del-2002-abstract.pdf

1082-DEL-2002-Claims-(09-06-2011).pdf

1082-DEL-2002-Claims-(16-03-2012).pdf

1082-DEL-2002-Claims-(19-03-2012).pdf

1082-del-2002-claims.pdf

1082-DEL-2002-Correspondence Others-(09-06-2011)..pdf

1082-DEL-2002-Correspondence Others-(09-06-2011).pdf

1082-DEL-2002-Correspondence Others-(16-03-2012).pdf

1082-DEL-2002-Correspondence Others-(19-03-2012).pdf

1082-del-2002-correspondence-others.pdf

1082-del-2002-correspondence-po.pdf

1082-DEL-2002-Description (Complete)-(09-06-2011).pdf

1082-del-2002-description (complete).pdf

1082-DEL-2002-Drawings-(09-06-2011).pdf

1082-del-2002-drawings.pdf

1082-DEL-2002-Form-1-(09-06-2011).pdf

1082-del-2002-form-1.pdf

1082-DEL-2002-Form-13-(16-03-2012).pdf

1082-del-2002-form-19.pdf

1082-DEL-2002-Form-2-(09-06-2011).pdf

1082-del-2002-form-2.pdf

1082-DEL-2002-Form-3-(09-06-2011).pdf

1082-del-2002-form-3.pdf

1082-DEL-2002-GPA-(09-06-2011).pdf

1082-del-2002-gpa.pdf

1082-del-2002-petition-138.pdf