Fluid intake and exhaust assemblies for positive displacement apparatus

Disclosed are intake and exhaust assemblies for forced air intake, reciprocating piston, internal combustion engine. Alternate embodiments of the air intake valve assembly include a hollow tube defining the intake port with means operatively coupling the tube and piston to respectively open and close the intake port in response to the reciprocation of the piston. The exhaust valve assembly includes operatively interrelated valve stem, spring retainer, rocker arm, and camming assemblies for alternatingly opening and closing the exhaust port for predetermined time intervals.

This invention pertains to positive displacement apparatus, and more 
particularly to internal combustion engines, and even more particularly to 
air intake and exhaust assemblies for two-stroke cycle engines. 
Developments are continuing to date to produce improved and more efficient 
internal combustion engines, particularly of the reciprocating piston 
type, in order to maximize the efficient utilization of fuel while at the 
same time minimizing the cost of production of the engines and the 
pollution produced thereby. In this regard, there are numerous advantages 
which can be realized by the use of two cycle engines for the production 
of the required motive power. As a consequence, research and development 
have been directed to improve the operating efficiency of these two cycle 
engines, particularly in the area of the intake and exhaust valve 
assemblies. For example, in the prior art patents to Adams Ser. No. 
877,818; Crimmins U.S. Pat. No. 1,786,106; Colter U.S. Pat. No. 1,787,856; 
Reilly U.S. Pat. No. 3,301,234; Von Steggern U.S. Pat. No. 3,363,611; 
Buchi U.S. Pat. No. 2,924,069; and Buchi U.S. Pat. No. 2,962,009, various 
types of interconnected intake and exhaust valve/piston assemblies are 
disclosed for use in two cycle engines. While such apparatus and 
assemblies are generally suited for their intended purposes, they are not 
entirely acceptable for all conditions of service and include structural 
and operating deficiencies which, as subsequently described, have been 
overcome by the apparatus of the present invention. 
It is therefore a principal object of the present invention to provide new 
and improved positive displacement apparatus, particularly of the 
reciprocating piston internal combustion engine type. 
It is another object of the invention to provide a new and improved 
two-stroke cycle internal combustion engine which is more efficient in 
terms of both construction and operation, and which provides more complete 
combustion, enhanced scavanging of combustion products, and improved 
cooling after combustion. 
It is an even further object of the present invention to provide a new and 
improved design for both the air intake and exhaust valve assemblies of a 
two-cycle internal combustion engine. 
In accordance with these and other objects, the present invention is 
directed to a forced air intake, reciprocating piston, internal combustion 
engine comprising alternate embodiments of an elongated, hollow air intake 
valve assembly operatively coupled with the reciprocating piston to 
alternately open and close off the intake port to the piston chamber. In 
addition, a uniquely designed exhaust valve assembly, operatively coupled 
with rocker arm and camming subassemblies, alternately open and close off 
the exhaust port from the piston chamber during predetermined time 
intervals during the operation of the engine.

Referring now to the drawings, the portion of an internal combustion engine 
pertinent to the present invention is depicted as including a main piston 
chamber 1 defined by the interior wall of a cylinder housing 2. The 
particular type of engine is not critical to the present invention and 
could be, for example, either of a conventional gasoline or diesel type. 
As is conventional, the cylinder 2 is formed as the upper portion of the 
engine block with a lower continguous portion 3 defining the crankcase of 
the engine, the engine head 4 closing off the top of the cylinder. It is 
to be understood that the particular engine may, if desired, include a 
number of cylinders, all of the type depicted in FIGS. 1 and 2, in which 
event the present description would similarly apply to each such cylinder. 
A piston 5 is mounted in the conventional manner for reciprocating movement 
within the chamber 1 and is connected to the crankshaft 7 by way of 
connecting rod 6. In the manner well known in the art, the crankshaft is 
eccentrically mounted to the drive shaft for rotation within the crankcase 
as the piston 5 reciprocates between an uppermost position (depicted in 
FIG. 1) and its lowermost position (depicted in FIG. 2). 
Extending through the engine head 4 is the nozzle portion of a fuel 
injector 8 for introducing the appropriate fuel into the piston chamber 1. 
The fuel injector can be any one of a variety of conventional designs 
which is appropriately controlled to inject the particular type of fuel at 
the optimum time. For example, in the case of a diesel engine, the diesel 
fuel would be injected at the desired point of ignition; while, in the 
case of a gasoline engine, the fuel injector would be effective to inject 
the gasoline immediately after the closing of the intake and exhaust 
valves (as subsequently described) in order to increase the time for 
uniform mixing of the air and fuel and to maximize the compression of the 
air/fuel mixture within the chamber 1. Furthermore, in the case of a 
gasoline type internal combustion engine, a spark plug (not shown) would 
be mounted in the engine head 4 for ignition of the fuel-air mixture. 
Mounted with the engine head 4 is an air intake conduit 10 through which 
air (in the direction of arrows 9) is forced for injection into the 
cylinder chamber 1. This intake air would originate from an external 
source (not shown) in communication with the conduit 10, such external 
source being any suitable type of air blower or pump, the details and 
operation of which would be conventional and not material to understanding 
of the present invention. 
In accordance with a unique feature of the present invention, air 
introduced into the intake conduit 10 would be injected into, or be 
prevented from entering the piston chamber, as a consequence of the 
respective opening or closing of an intake valve assembly 11, the details 
and operation of which are now described. 
Accordingly, the intake valve assembly 11 comprises an elongated hollow 
tube 12 defining an axially extending intake port 13 providing fluid 
communication between the interior of the conduit 10 and an opening 14 at 
the base of the tube. The base of the tube terminates in an enlarged 
flared portion 15 (defining the opening 14); and an annular stop member 16 
is threadably or rigidly secured at the opposed end thereof, as depicted 
in the drawings. The tube 12 is slidably mounted in the engine head 4 so 
as to enable reciprocating movement through, and in the axial direction 
of, the piston chamber 1, the stop 16 thus limiting the downward travel of 
the valve assembly 2 (as a consequence of its engagement with the engine 
head surface 4a). 
Rigidly attached (for example, by threaded connection) to, but spaced from, 
the base of the tube 12 is a valve lifter assembly 17 which is disposed 
within a hollow segment of the piston 5. As illustrated in the drawings, 
the lifter assembly 17 is joined to the tube 12 by a stem 18 which is 
slideably and axially mounted through an opening in the top wall of the 
piston 5. A pair of springs 50 are disposed intermediate valve lifter 
segment 17 and the upper interior wall portion of the piston and are 
effective to normally bias the lifter segment (and therefore the entire 
tube 12) in the downward direction and, as subsequently described, to urge 
the flared portion 15 against a recessed valve seat 51 defined at the top 
surface of the piston. It is thus apparent when the tube is so biased, the 
opening 14 will be closed off preventing air flow through the intake port 
13. 
An exhaust valve assembly 21 alternately opens and closes off an exhaust 
port 20 provided in the engine head 4 for predetermined time intervals 
during the operation of the engine. Specifically, the exhaust valve 
assembly includes an elongated valve stem 30 having a disc 31 at one end 
and a spring retainer 33 at the opposite end, the stem 30 being slideably 
mounted within the engine head 4 and reciprocated in the manner 
subsequently described to alternately position the disc 31 for 
respectively opening and closing the exhaust port 20. A spring 32, 
disposed around the stem 30 and intermediate the engine head 4 and the 
spring retainer 33, normally biases the exhaust valve assembly to its 
closed position (position depicted by solid lines in FIG. 1). 
Mounted within a chamber 24 defined by a housing 22 is a rocker arm 
assembly 23 which, under control of a camming assembly 25, is effective to 
translate the stem 30 to position the exhaust valve assembly to its open 
position (position depicted in FIG. 2). More particularly, the camming 
assembly includes a cam shaft 27 which is rotated (by means not shown) to 
rotate cam 26 against one end 23a of the rocker arm, thus rotating rocker 
arm assembly 23 in the counterclockwise direction and consequently 
translating the valve stem 30 (and disc 31) to open the exhaust port 20. 
The continued rotation of the cam shaft then enables the rocker arm 
assembly to return to its original position with the spring 32 translating 
the exhaust valve assembly back to its closed position. 
From the previous description, it is thus apparent that by controlling the 
operating sequence of the camming assembly, the duration of time that the 
exhaust port remains open (or closed) can be similarly controlled. This 
control feature is particularly advantageous in the case of a gasoline 
combustion engine where it is desirable, at high RPM, to maintain a full 
cylinder of air; while, at low RPM, this would not be the case. Thus, 
during low RPM, the rotation of the cam shaft 27 can be controlled to 
maintain the exhaust valve assembly in its open position for a longer 
period of time than during high RPM, the piston 5 forcing the excessive 
air out of the exhaust port 20, thus keeping the fuel-air mixture in 
balance while maintaining increased engine efficiency since compression of 
excessive air (and the consequent waste of power) would be avoided. 
The operation of the assembly of the present invention is now described. 
Accordingly, it is initially assumed that the operating cycle of the 
engine is in the operating phase depicted in FIG. 1 with the piston 5 at 
its uppermost position and the exhaust valve assembly 21 in its closed 
position (thus closing off exhaust port 20). As a consequence, the chamber 
1 is at maximum compression and ignition of the fuel-air mixture in the 
chamber would occur (spontaneously, in the case of a diesel engine and by 
operation of the spark plug, in the case of a gasoline engine). At such 
time, and as depicted in FIG. 1, the intake valve assembly 11 will be 
seated against the top of the piston with the air intake port 13 being 
consequently closed. 
Upon ignition of the fuel-air mixture, the piston will be forced downward; 
and as a consequence of the spring biasing of the tube 12 against the top 
of the piston, the entire intake valve assembly 11 will initially travel 
with, and follow, the piston during this downward stroke. Just prior to 
the piston reaching its lowermost position (preferably about 30.degree. to 
40.degree. before the completion of such cycle), the exhaust valve 
assembly 21 under control of the camming assembly 25, will begin to open, 
thus enabling the initial exhaustion of the combustion products through 
the exhaust port 20. 
Shortly following the initial opening of the exhaust port, as just 
described, and as a consequence of stop member 16 engaging engine head 
surface 4a, the intake valve tube 12 will begin to separate, and be 
unseated, from the piston, thus resulting in the intake port 12 opening to 
enable the introduction of another charge of compressed air to the chamber 
1. The air thus introduced into the piston chamber will force escapement 
of the combustion products out the exhaust port. 
When the piston reaches its lowermost position (position depicted in FIG. 
2), the intake valve assembly 11 is at its fully open position with the 
springs 50 fully compressed. The piston 5 then begins its upward stroke 
until it again engages the tube 12, thereby to translate the tube to lift 
the stop member 16 off surface 4a, the valve portion 15 again being 
reseated within the valve seat 51 to close the intake port. At 
approximately the same time, the exhaust valve assembly 21 will be 
returned (by spring 32) to its closed position, thus increasing the 
compression of the intake air within chamber 1. The entire assembly then 
returns to the original position depicted in FIG. 1 and the cycle is 
completed. 
The fuel injector 8 would be operated, during this sequence, in accordance 
with the desired point of fuel injection. Specifically, in the case of a 
gasoline engine, the fuel would be desirably injected immediately 
following the time when both the intake port 13 and exhaust port 20 are 
closed (which, as described, occurs prior to the time that the piston 
reaches its uppermost position). Thus, the continued upward travel of the 
piston not only compresses the fuel-air mixture, but assures complete 
mixing thereof. In the case of the diesel engine, operation of the fuel 
injector would be delayed until maximum air compression within the piston 
chamber. 
Referring now to FIGS. 3 and 4, an alternate embodiment of the intake valve 
assembly 11 is now described. The assembly is similar to that described 
with respect to FIGS. 1 and 2 in that the elongated hollow tube 12 
defining the intake port 13 is slidably mounted through the engine head 4 
for reciprocating movement through, and in the axial direction of, the 
piston chamber 1 and conduit 10; and the flared portion 15 is adapted for 
mating reception in the recessed piston seat 51. For convenience of 
illustration, the remaining portions of the housing, crankcase, etc. have 
been broken away in FIGS. 3 and 4, it being understood that these missing 
portions would be the same as depicted in FIGS. 1 and 2. 
In this embodiment, however, the intake valve assembly 11 is operatively 
coupled with the piston 5 by way of a spring retainer assembly 70 defined 
by an elongated stem 60 axially extending through the intake port 13 and 
having one end threadably coupled with the piston 5 and the opposed end 
terminating in a flared head portion 61. The head portion 61 has a size 
and configuration adapted to slidably engage the interior wall of the 
conduit 10, openings 62 being provided therein so that air entering 
conduit 10 can flow through head 61 into intake port 13. 
Disposed intermediate the head 61 and the enlarged stop member 16' is a 
spring 80 which is effective to urge the tube 12 downwardly toward the 
face of the piston 5. 
In a manner similar to that previously described, when the piston 5 is at 
its uppermost position (FIG. 3) the valve 11 will be closed with the tube 
12 (specifically flared portion 15) being retained against the piston 5 
(specifically valve seat 51). As the piston travels downward, the spring 
80 (and spring retainer assembly 70) will maintain the tube 12 in this 
seated position (and thereby maintain the intake valve assembly closed) 
until the stop 16' engages head surface 4a. Further downward travel of 
piston 5 will then cause the piston and tube to separate (FIG. 4) with the 
consequent opening of the intake valve assembly 11 and the introduction of 
air from conduit 10 through the port 13 and into the chamber 1. 
The described preferred embodiments of the invention provide, among other 
advantages, a substantially more efficient, two-cycle internal combustion 
engine due largely to the reduction of friction which will be encountered 
during the power stroke as well as enhanced scavanging of the combustion 
products from the cylinder chamber. Furthermore, the forced intake air 
provides increased cooling during the exhaust cycle; and the cooling of 
the combustion chamber by the forced air enhances the potential for 
controlling nitrous oxides. The two-cycle engine of this invention, which 
would be of decreased weight, size and complexity, would provide, due to 
the uniquely designed and cooperating intake and exhaust valve assemblies, 
a more complete and thorough combustion within the piston chamber, thus 
improving the power efficiency while reducing the pollution by-products. 
While the invention has been particularly described with reference to an 
internal combustion engine, it will be apparent to one skilled in the art 
that such design can be easily modified for other types of positive 
displacement devices, such as pumps. Various other modifications and 
improvements may be made by those skilled in the art without departing 
from the spirit and scope of the invention as defined by the appended 
claims.