Internal-combustion engines – Means to whirl fluid before – upon – or after entry into...
Reexamination Certificate
2000-04-11
2001-05-22
Kamen, Noah P. (Department: 3747)
Internal-combustion engines
Means to whirl fluid before, upon, or after entry into...
C123S188200
Reexamination Certificate
active
06234142
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to valves used in internal combustion engines and, more particularly, to overhead valves especially shaped to enhance fuel and air mixing for improved combustion efficiency and engine performance.
2. Description of the Related Art
Internal combustion engines are well known in a wide variety of configurations and applications. A long series of refinements have been applied in efforts to improve the performance of such engines. Much attention has been focused on improving the efficiency of combustion of the fuel and air mixture within the cylinder's combustion chamber.
A number of approaches have been tried in order to obtain increased engine performance, either alone or in combination. Specially shaped combustion chambers, increased number of valves per cylinder, specially shaped piston faces, and a wide variety of spark plug positions and configurations have all been explored and used with varying degrees of success.
Since the invention of the internal combustion engine, a significant amount of attention has been directed to the improvement of valve design. The valves that control the flow of the intake and exhaust charges in most engines are of the poppet type, which means that they move in and out of the valve ports in order to open and close the passage. During operation of the conventional internal combustion engine, cams on a rotating camshaft operate to lift the tappets, which in turn lift the pushrods and actuate the rocker arms, which push down on the tips of the valves. When this happens, the valves are lifted off their seats and allow either intake or exhaust gases to flow in or out of the combustion chamber.
In efforts to improve airflow into and out of the combustion chamber, various aspects of the valves have been modified in a variety of ways. Many of these valve shape modifications affect engine performance, but no one particular design necessarily performs better than another. Rather, a particular valve design complements a given port of a given head in order to produce the best flow. For example, Chrysler's famous “Hemi” engine incorporated a valve that resembled a tulip bulb at the valve fillet. It was Chrysler's opinion that this shape maximized flow through the intake ports of the heads used on those engines.
Various valve designs have addressed different portions or features of the overall valve. The angle of the valve face and the angle of the valve seat have frequently been varied, either independently or in cooperation. “Top cut” angles and “bottom cut” angles on either side of the valve seat formed in the engine head have been varied to improve performance. Valve stems have been “necked down” in the portion of the stem that will occupy the port, in order to reduce flow restriction and, further, to reduce slightly the weight of the valve. Stem lengths have been varied in order to accommodate different engine head thicknesses or to avoid coil bind in the valve spring. The height of the valve margin, or thickness of the valve head, has also been varied in efforts to improve flow.
As can be discerned from the above discussion, much time and effort have been directed to improve flow past engine valves. Other efforts have been directed at designing improved piston faces that will “swirl” the contents of the combustion chamber during the compression stroke and thereby improve combustion efficiency. Spark plug position and spark plug design have also been used to improve efficiency of combustion.
SUMMARY OF THE INVENTION
In brief, particular arrangements in accordance with the present invention provide a modified engine valve for use in internal combustion engines. The modification comprises the addition of a shroud in the form of a wall extending from the inner face of the intake valve and partly around the circumference thereof. More particularly, the shrouded engine valve of the present invention may be used to significantly improve the efficiency of combustion and thereby the performance of an engine. The shrouded valve is installed and positioned such that the shroud wall serves to direct and swirl into the combustion chamber the mixture of fuel and air. Swirling the fuel and air mixture within the combustion chamber develops increased combustion efficiency and thereby better engine performance.
By positioning the shrouded valve of the present invention such that the opening in the shroud wall is located toward the piston (i.e., generally toward the center of the cylinder) for maximum efficiency, the flow of the fuel-air mixture is swirled into the combustion chamber on the engine's intake stroke as the intake valve opens and the mixture is drawn into the cylinder past the intake valve. In accordance with one particular aspect of the invention, the circumferential extent and/or height of the shroud wall may be varied to achieve the best performance in different types of engines. In one particular engine on which performance tests of my shrouded valves have been run, the engine was a 350 cubic inch V-8, the shroud was approximately one-half inch in height and extended 220° about the periphery of the valve.
The results of smog emission tests are shown on the following table which shows the emissions of various constituents for a 350 cubic inch V-8 Chevrolet engine equipped with standard valves and for the same engine equipped with shrouded valves of the present invention, taken at 850 and 2500 revolutions per minute (rpm), respectively. With standard valves, the engine was tested with standard smog equipment. In the test of the shrouded valve engine, the engine was not equipped with either a catalytic converter or other smog equipment.
350
V-8
SMOG EMISSION TEST
Chevrolet
HC
CO
NO
CO
2
O
2
RPM
REMARKS
Standard
220
2.0
850
Valve
180
1.7
2500
Shrouded
189
1.70
54
11.0
4.12
850
No Smog
Valve
Equipment
80
.49
78
10.0
5.17
2500
No Smog
Equipment
HC—Hydrocarbons, PPM (parts per million)
CO—Carbon monoxide (percent)
NO—Nitric oxide, ppm (parts per million)
Tests were also performed in the test automobile, a Model A Ford with 350 cubic inch V-8 engine conversion, under ordinary driving conditions. On the street, fuel consumption was 8.59 miles per gallon (mpg) whereas in freeway driving for approximately 40 miles the fuel consumption was 14.75 mpg.
The advantages of the present invention are numerous and varied. The configuration of the shrouded engine valve develops a vortex swirling the fuel and air mixture, thereby increasing the efficiency of combustion. This increased efficiency of combustion translates into smoother idle performance with lower exhaust temperature, reduced fuel consumption, and reduced exhaust emissions of the kind that result from incomplete burning of the fuel air mixture. In a smog test conducted on the 350 cubic inch V-8 engine equipped with shrouded valves in accordance with the present invention, installed in a Model A Ford, it was found that the engine met the 1998 standards of the State of California without either a catalytic converter or an air pump, accessories which have been customarily used in various engines to develop more complete combustion of the fuel-air mixture with lower levels of smog constituents in the exhaust. This clearly demonstrates the efficacy of the present invention as it relates to improvement of internal combustion engine emissions.
In the operation of the engine on a test stand, to test for fuel efficiency, the engine equipped with the shrouded valves was clearly more fuel efficient than the engine without the shrouded valves. This test was under no-load conditions. The conventional valve engine ran for 4.6 minutes on 16 oz. of gasoline. The shrouded valve engine ran for 6.8 minutes on 16 oz. of gasoline, an improvement in efficiency of 48%.
Structurally, the shrouded engine valve of the present invention provides a simple and inexpensive means for greatly improving the performance of internal combustion engines. In one embodiment, the invention incorporates a two-piece design, although unitary manu
Bissell Henry M.
Bissell, IV Henry M.
Kamen Noah P.
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