High efficiency combustion chamber system

An intake and exhaust system for use with internal combustion engines that uses two intake valves and one exhaust valve for each engine cylinder. The three valves are preferably round and spaced substantially uniformly in the cylinder head around the cylinder centerline. For best results, the two intake valves have substantially equal diameters, with the diameter of the exhaust valve having a ratio to the diameter of an intake valve of from about 1:1 to about 1:1.2. Preferably one axial, three peripheral or an axial and three peripheral spark plugs equally spaced around the cylinder axis each centrally located in one of the areas between adjacent valves and the edge of the cylinder. The head has three substantially hemispheric depressions each housing one of said valves. This invention provides a fast and uniform lean burn, permits use of a high compression ratio and lower octane, unleaded gasoline and provides improved thermal efficiency.

BACKGROUND OF THE INVENTION 
This invention relates in general to improvements in internal combustion 
engines and, more specifically, to an improved cylinder head and piston 
arrangement with an improved valve and spark plug layout for use in those 
engines. 
A great many different intake and exhaust valve arrangements have been 
developed over the years for use in internal combustion engines, in 
particular for use in automobiles. Most such engines use one intake valve 
and one exhaust valve at each cylinder with a single spark plug. The prior 
art arrangements utilize exhaust area/intake area in the range well above 
65%. A great deal of effort has gone into optimizing the sizing and 
placement of the valves, the shape of the combustion chamber and the like. 
Since there is a great need for improvements in automobile fuel efficiency 
while maintaining or improving performance, a wide variety of different 
valve and spark plug configurations and arrangements have been designed 
and tested. In some of these, multiple valves and spark plugs have been 
used. 
An arrangement of four valves per cylinder, two intake valves and two 
exhaust valves, has been disclosed, for example, by Akana in U.S. Pat. No. 
3,411,490. Today, a number of high performance automobiles use four valve 
systems, with one or more spark plugs. In these high performance 
automobiles, several spark plugs may be provided around the periphery of 
the combustion chamber with an additional spark plug centrally located. 
Manufacture and operation of these four valve, multiple spark plug engines 
is complex and expensive and requires complex computer control for 
efficient operation. 
Weslake in U.S. Pat. No. 2,652,039 describes a complex cylinder head 
arrangement for an internal combustion engine having a wedge-shaped 
combustion chamber adjacent to the cylinder feeding into a cylinder 
chamber above the piston. The combustion chamber has an intake valve, an 
exhaust valve and a single spark plug. A second intake valve is provided 
in the cylinder chamber. A weak mixture of air and fuel enters the 
combustion chamber, combustion begins and a rich mixture enters through 
the cylinder chamber and adds to the original combusting mixture. This 
very complex system appears to have been unsuccessful and to never have 
been brought into production. 
Another three valve system is described by Von Segern et al in U.S. Pat. 
No. 3,443,552. Here, a basically conventional cylinder head having a 
single intake valve and a single exhaust valve with a primary, 
conventional, combustion chamber is provided. In addition, a centrally 
located auxiliary chamber is located on the cylinder axis away from the 
cylinder in gas flow communication with the primary combustion chamber. 
The auxiliary chamber has a single intake valve and a spark plug. 
Combustion begins in the auxiliary chamber, spreads to the main combustion 
chamber where added fuel mixture is introduced. Again, this is a complex 
and cumbersome system that appears to have been found to be impractical. 
Thus, while a great number of different arrangements of multiple valves 
and/or multiple spark plugs have been designed, none have provided an 
optimum combination of structural simplicity, maximum fuel efficiency, low 
emissions and highest performance. Thus, despite the crowded nature of the 
automobile engine fuel and air introduction and exhaust removal art, there 
remains a continuing need for improvements providing greater overall 
efficiency at lowest cost. 
It is, therefore, an object of this invention is to provide a simple, 
easily manufactured internal combustion engine combustion chamber system 
having increased operating efficiency. Another object is to provide such 
as system that provides both increased fuel efficiency, low emissions and 
higher performance. A further object is to provide such a system with high 
thermal efficiency. Yet another object is to provide a system capable of 
operating at high compression ratios with a variety of different fuels. 
SUMMARY OF THE INVENTION 
The above-noted objects, and others, are accomplished, basically, by a 
three valve combustion chamber system for use with internal combustion 
engine containing a piston and a cylinder head forming a combustion 
chamber therebetween. The system comprises three valves in the cylinder 
head, spaced substantially equally around the cylinder axis, two of the 
valves adapted to act as intake valves and the third as an exhaust valve. 
The two intake valves preferably have the same diameter and surface area, 
with the exhaust valve preferably having the same or slightly greater 
diameter. The ratio of total exhaust valve cross-sectional area/total 
intake valve cross-sectional area is ideally less than 65% and can be in 
the range of 50% to 65%. 
In a first version, three peripheral spark plugs are substantially 
centrally located in the areas surrounded by adjacent valves and the edge 
of the combustion chamber. A central, fourth, spark plug may be located 
substantially on the cylinder axis, surrounded by the three valves. A 
second version has a single central spark plug located substantially on 
the cylinder axis, surrounded by the three valves. If desired, the system 
of this invention may be used in a diesel or other engine using an 
ignition system other than a spark plug. 
The cylinder head surface forming one side of the combustion chamber has 
hemispheric depressions containing each of the valves, with the piston 
having approximately flat areas corresponding to the approximately flat 
areas on the cylinder head located between adjacent valves and the edge of 
the combustion chamber. These opposed flat areas are configured so that as 
the flat piston and head areas closely approach each other during engine 
operation a very efficient "squish" area is created. This arrangement 
substantially improves combustion and fuel efficiency.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring to FIGS. 1 and 2, there is seen a cylinder head 10 having a 
recessed combustion chamber 12. Head 10 has a number of conventional bolt 
holes, vents and the like for attachment of the head to the engine block 
(not shown) and other purposes. Two intake valves 14 open to allow entry 
of air or an air-fuel mixture into combustion chamber and closed during 
combustion. One exhaust valve 16 is closed during combustion and opens to 
allow egress of exhaust gases. Optimally, the faces of valves 14 and 16 
are circular and the three valves are substantially uniformly arranged 
around the cylinder and combustion chamber axis. The shafts may be canted 
to the cylinder centerline or vertical; that is, parallel to the cylinder 
centerline, as desired. 
The faces of intake valves 14 preferably have the same area so that 
identical open areas are provided when the valves open and gas flow 
therethrough is uniform in pattern and volume for optimum efficiency. 
Exhaust valve 16 ideally has a diameter equal to or slightly greater than 
that of an intake valve 14, preferably a diameter ratio of from about 1:1 
to about 1:1.2. The ratio of total exhaust valve cross-sectional 
area/total intake valve cross-sectional area is ideally less than 65% and 
can be in the range of 50% to 65%. 
The utilization of the small exhaust port cross-sectional area and valves 
provides high exhaust gas velocity, on the order of 450 ft/sec. Intake gas 
velocity, depending on mass, volume and/or the presence of fuel would be 
in the 225 to 300 ft/sec range. This configuration yields excellent 
operating characteristics, including throttle response, exhaust gas 
scavenging, charge purity and octane tolerance. Improved thermal 
efficiency equates to significantly reduced heat transfer. 
In the embodiment of FIG. 1, one central spark plug 18. A central spark 
plug 18 is shown located substantially on the cylinder centerline and may 
extend above the surface of the combustion chamber 12, in the preferred 
arrangement, as shown or may be recessed slightly below the surface, if 
desired. 
In the alternative embodiment shown in FIG. 3, three equidistantly spaced 
spark plugs 20 are used. While optimum efficiency may in some instances by 
the addition of a fourth spark plug centrally located in the FIG. 3 
embodiment, the embodiment of FIG. 3 is less costly and in many cases 
provides more or at least sufficient efficiency. 
If desired, only a single central spark plug 18 may be used. 
FIG. 4 shows the face of a piston 24 optimized for use with the combustion 
chamber 12 arrangement shown in FIGS. 1-3. It should be understood that 
FIG. 4 could also pertain to the inner surface of the cylinder head 
equally as well. For optimum combustion a "squish+ area is often desired 
between portions of the opposed faces of piston 24 and/or combustion 
chamber 12. In that case, the areas 22 are flat and slightly tapered away 
from piston toward the combustion chamber centerline and the corresponding 
areas 26 are similarly flat and slightly tapered so that those areas 
closely approach each other as piston 24 makes its closest approach to 
combustion chamber 12 during engine operation, squeezing the fuel/air 
mixture in those areas toward the center of combustion chamber 12. Areas 
22 and 26 lie approximately perpendicular to the centerline of the 
combustion chamber and cylinder. This "squish" effect has been found to 
improve combustion efficiency. Recessed areas 28 are formed in the face of 
piston 24 around central pad 30 or cylinder head to provide the desired 
compression ratio in conjunction with the squish areas. Recessed areas 28 
are sized to provide the desired compression ratio in conjunction with the 
squish areas. 
Other applications, variations and ramifications of this invention will 
occur to those skilled in the art upon reading this disclosure. Those are 
intended to be included within the scope of this invention, as defined in 
the appended claims.