Internal-combustion engines – Particular piston and enclosing cylinder construction – Piston
Reexamination Certificate
1998-07-31
2001-01-09
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Particular piston and enclosing cylinder construction
Piston
Reexamination Certificate
active
06170454
ABSTRACT:
BACKGROUND
1. The Field of the Invention
This invention relates to internal combustion engines and, more particularly, to novel systems and methods of a piston to be used in an internal combustion engine.
2. The Background Art
For many years internal combustion engines have been used to benefit society. The internal combustion engine, first developed many years ago, has undergone many improvements over the years. Typical internal combustion engines have a cylinder block. A cylinder bore is formed within the cylinder block. The engine includes a cylinder head mounted on the cylinder block. A piston reciprocates within the cylinder bore. The chamber defined by the cylinder head, the top part of the piston, and the cylinder wall is referred to as the combustion chamber.
The cylinder head houses the intake valve and the exhaust valve. An air/fuel mixture is fed into the combustion chamber through the intake valve. A typical engine cylinder head includes a spark plug mounted on the cylinder head so that a spark created by the spark plug is located within the combustion chamber. So placed, the spark ignites the air/fuel mixture and results in combustion. The exhaust created by the combustion is forced out of the combustion chamber through the exhaust valve.
Operation of typical internal combustion engines can be divided into four strokes: the intake stroke, the compression stroke, the power or combustion stroke, and the exhaust stroke. During the intake stroke, the piston moves downwardly in the cylinder bore and an air/fuel mixture is fed into the cylinder bore through the intake valve. Next, during the compression stroke, the piston moves upwardly in the cylinder bore, compressing the air/fuel mixture within the combustion chamber. Then, the air/fuel mixture is ignited, typically by a spark from a spark plug. After ignition is the power or combustion stroke where the piston is forced downward in the bore from the forces of the combustion. Finally, there is the exhaust stroke, where the piston moves upwardly in the cylinder bore forcing exhaust out of the exhaust valve, which has been opened for this purpose.
The air/fuel mixture quality is a key to an efficient power stroke. Often the air/fuel mixture tends to separate. As a result, the fuel droplets within the combustion chamber get larger and larger. The larger the fuel droplets are, the more separated the air and fuel are resulting in a less efficient power stroke. The ability to efficiently homogenize and maintain the blend prior to and during the burn is a classical combustion engine problem.
Poor homogeneity of the air/fuel mixture can result in an unequal amount of fuel in each cylinder of the engine. An unequal amount of fuel resulting from poor mixture homogeneity creates an eventual combustion pressure imbalance, cylinder-to-cylinder.
Typical piston heads are flat on top or dish shaped with a flat bottom to the dish. During the compression stroke the piston moves upwardly in the cylinder compressing the air/fuel mixture. As the piston approaches the top of the cylinder, the air/fuel mixture is compressed and spread substantially equally in the combustion chamber. Accordingly, the ignition point, usually the tip of a spark plug, is near only a certain portion of the compressed air/fuel mixture. Because only a certain amount is proximate the ignition point, the burn that results is less efficient than it could be.
After the combustion of the air/fuel mixture, the combustion chamber contains exhaust. During a typical exhaust stroke, much of the exhaust is forced out of the exhaust valve. However, a portion of the exhaust remains within the combustion chamber. This leftover exhaust results in less volume being available for new air/fuel mixture being drawn into the chamber during the following intake stroke. With less air/fuel mixture drawn in, less power can be created.
BRIEF SUMMARY AND OBJECTS OF THE INVENTION
In view of the foregoing, it is a primary object of the present invention to provide a piston for use with an internal combustion engine capable of increasing the efficiency of the engine.
Another object of the present invention is to improve combustion efficiency.
It is also an object to improve the air/fuel mixture quality.
Another object of the present invention is to homogenize the air/fuel mixture.
An additional object is to more effectively force exhaust out of the exhaust valve.
A further object of the present invention is to maximize the burn by concentrating the air/fuel mixture toward the ignition area of the internal combustion engine.
A still further object of the present invention is to balance the combustion pressure between cylinders.
Another object is to create more power within the engine.
Consistent with the foregoing objects, and in accordance with the invention as embodied and broadly described herein, a piston for use with an internal combustion engine is disclosed in one embodiment of the present invention as including a crown having an exhaust valve area, an intake valve area, and means for moving exhaust toward the exhaust valve area. The exhaust moving means includes means for homogenizing the air/fuel mixture. The homogenizing means may also include means for creating eddies with the air/fuel mixture. In addition, the piston may include means for concentrating the air/fuel mixture toward the area of ignition. In one presently preferred embodiment, the structure used to accomplish the invention may include a raised portion formed on the crown of the piston. The raised portion increases in height from the center of the crown toward the perimeter of the crown. The raised portion also has an arcuate shape declining in height along the arcuate shape. The raised portion includes a plurality of dimples formed therein for creating eddies within the air/fuel mixture.
REFERENCES:
patent: D. 377493 (1997-01-01), Oda et al.
patent: 1674733 (1928-06-01), Maher
patent: 3601008 (1971-08-01), Alexander
patent: 3766900 (1973-10-01), Aiti
patent: 4046116 (1977-09-01), Burnham
patent: 4050420 (1977-09-01), Cataldo
patent: 4114518 (1978-09-01), Glover, Jr. et al.
patent: 4166436 (1979-09-01), Yamakawa
patent: 4235203 (1980-11-01), Thery
patent: 4289099 (1981-09-01), Nakanishi et al.
patent: 4291662 (1981-09-01), Nakamura et al.
patent: 4296720 (1981-10-01), Nakanishi et al.
patent: 4300499 (1981-11-01), Nakanishi et al.
patent: 4318376 (1982-03-01), Nakamura et al.
patent: 4324214 (1982-04-01), Garcea
patent: 4467752 (1984-08-01), Yunick
patent: 4541377 (1985-09-01), Amos
patent: 4557231 (1985-12-01), Thery
patent: 4565181 (1986-01-01), August
patent: 4567863 (1986-02-01), Fletcher
patent: 4587932 (1986-05-01), Moebus
patent: 4617888 (1986-10-01), Dent
patent: 4694735 (1987-09-01), Tatematsu et al.
patent: 4893596 (1990-01-01), Nonaka
patent: 4987865 (1991-01-01), Schenkel
patent: 5007394 (1991-04-01), Brychta et al.
patent: 5113817 (1992-05-01), Kemnitz et al.
patent: 5224449 (1993-07-01), Fukano et al.
patent: 5317958 (1994-06-01), Leites et al.
patent: 5511521 (1996-04-01), Bischofberger et al.
patent: 5601010 (1997-02-01), Sawada et al.
patent: 5660156 (1997-08-01), Whitacre et al.
patent: 5727535 (1998-03-01), Wallace
Falkenrath Jack Dean
McFarland James D.
Broadbent Berne S.
Hulse Dale E.
Kirton & McConkie
McMahon Marguerite
Techniphase Industries, Inc.
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