The present invention relates to a valve and, more particularly, to a pneumatically actuated valve for use as an intake and/or exhaust valve on either a two- or four-stroke internal combustion engine.
Generally, four stroke internal combustion engines utilized valves to allow exhaust to leave the working (combustion) chamber of the engine cylinder after the combustion stroke, as well as to allow a new air charge to enter the cylinder to begin the cycle anew during the intake stroke. Two stroke internal combustion engines on the other hand may utilize valves for both intake and exhaust or a valve for intake and a port for exhaust. Such valves have traditionally been invariably actuated by a cam affixed to a shaft (the cam shaft), or alternatively by an electromagnetic or hydraulic device.
It would be greatly advantageous to provide another more efficient way to actuate valve reciprocation on internal combustion engines. Valves which rely on a cam shaft usually require heavy springs and a large number of other moving parts that absorb a large amount of energy and create a great deal of friction. Additionally, such systems are relatively expensive to operate.
U.S. Pat. No. 6,349,691 to Klein (one of the inventors named herein) describes a partial solution in the form of a valve for air intake. The valve is responsive to pressure differential between the manifold and combustion chamber. Specifically, the valve closes in response to the increase in pressure in the cylinder as the piston rises (after passing bottom dead center and approaching the top of the cylinder). Unfortunately, a problem with this intake valve assembly is that inertia and, to a lesser extent friction, retards the valve's speedy closure, thus negatively affecting engine performance.
Therefore, it would be advantageous to provide an externally regulated pressure actuated valve system.
The present inventors have also filed U.S. patent application Ser. No. 10/449,754 on May 30, 2003, which introduces a system of using a spring to accelerate the valve closing, and a means to vary non-cyclically the base force of the spring so that the proper amount of spring force can be used under varying conditions of engine speed and load. While this variable spring force intake valve system is reliable, it still presents a lingering concern. Specifically, when the spring force is adjusted (i.e. during a regime of higher engine speed) the period of time during which the valve is open to allow ventilation is shortened. Thus, an insufficient amount of intake air enters the cylinders, negatively effecting engine performance.
Additionally, the present inventors have filed a U.S. Provisional Patent Application No. 60/444,532 on Jan. 31, 2003, which introduced another more energy efficient intake valve assembly. The provisional patent application disclosed both a unique compressed air actuated intake valve system (either wholly air operated or spring-assisted) and a unique air distribution system using a single air source for actuating the intake valve. The valve is short and lightweight, having collar. The valve sits in a housing atop an engine cylinder and is connected to the air distribution system. Compressed air is either directed over the top of the valve forcing it downward and open or into a hollow chamber within the valve housing where the compressed-air applies pressure under the valve collar, forcing the valve upward and closed. The disclosed air distribution system uses a rotating disk assembly with air outlets to direct airflow as necessary to raise and lower the valve. While the valve assembly disclosed in this provisional patent application is sound, there is a slight disadvantage associated with this air distribution system. Namely, the air distribution system, as disclosed, requires lubrication for the rotating disks and upon heating the presently available lubrications may release unwanted and harmful hydrocarbons into the atmosphere. Additionally, the valve was illustrated for use only as an intake valve, not as either an intake or exhaust valve.
It would be advantageous over the prior art to provide a wholly forced-air actuated valve system, using one or multiple air sources, operable on either a four stroke or a two stroke internal combustion engine, to open and/or close intake and/or exhaust valves. It would also be advantageous to provide a system for efficiently regulating the timing of the valve open/close (reciprocation) cycle relative to the engine speed. It would further be advantageous to provide such a system that does not require the use of lubricants that may release harmful by-products into the environment.
The present invention is a wholly pneumatically actuated valve assembly including a valve, a valve housing, and a compressed-air or other gas distribution and timing mechanism. The valve assembly is similar to the sliding valve assembly, described in U.S. Pat. No. 6,349,691, having been modified and improved such that it is able to accommodate forced-air actuated reciprocation. Specifically, the valve is comprised of a relatively short and low mass hollow cylindrical body with an upper and lower end. Encircling and either attached to or formed as an integral part of the hollow cylindrical body towards the upper end is a collar. The upper end of the cylindrical body is opened. The lower end of the hollow cylindrical body includes a plurality of ports (i.e. elliptical ports) along the circumference and an endplate or cap closing the lower end of the hollow cylindrical body. The lower end of the cylinder is slightly flared (i.e. 45 degree angle) to form a valve seat. The valve is positioned in a hollow tubular housing that creates a passage through the engine's cylinder head to the combustion chamber. Sliding the valve up and down within the housing closes and opens the valve, respectively. The housing has two inner sections with differing diameters, a smaller diameter lower section adjacent to a larger diameter upper section. The smaller diameter lower section of the housing is nearest of the combustion chamber and its diameter is such that it accommodates with minimal clearance the sliding movement of the valve body. The larger diameter upper section is nearest the outer surface of the engine and its diameter is such that it accommodates with minimal clearance the sliding of the valve collar. The adjacent position of the differing diameter housing sections necessarily creates a shelf that limits the downward motion of the valve.
Additionally, the valve housing may be configured with a housing cap attached to the upper section of the housing adjacent the outer surface of the engine. This cap covers the collar but not the open upper end of the hollow cylindrical body.
The valve is actuated by directing forced air towards one or more actuation areas, relative to the valve collar to force the valve to slide up or down. For valve assemblies in which compressed air is used only to close the valve, there is one actuation area beneath the valve collar. If compressed air is used to both open and close the valve, there are two actuation areas, one above and one below the valve collar. In both embodiments, the valve housing contains a hollow air feed channel with one end connected to a forced air source and the other end opening into the valve seat beneath the valve collar. Thus, the valve, particularly the underside of the valve collar, is exposed to the channel. For valves with two actuation areas, the housing cap further comprises a hollow air feed channel with one end connected to a forced air source and the other end opening into the valve seat above the valve collar. Thus, the valve, particularly the top of the valve collar, is exposed to the hollow channel. Forced air alternately directed into these hollow air feed channels will close and open the valve, respectively.
Compressed air, either from a single or multiple sources, is manifolded to the hollow air feed channels. Forced air distribution and timing mechanisms are used to regulate forced air flow into the hollow air feed channels in order to actuate and control valve reciprocation.
Alternative embodiments, utilize a vacuum in the area under the valve collar in order to slide the valve downward and open in conjunction with compressed air forced under the valve collar to slide the valve upward and closed.
In the preferred embodiment of the present invention an electro-mechanical valve assembly regulated by a programmable controller is used as the forced air distribution and timing mechanism. In another embodiment a rotational disk assembly secured within an air input manifold is used to regulate distribution and timing of forced air flow.
Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments and certain modifications thereof when taken together with the accompanying drawings in which:
The present invention is a pneumatically actuated valve assembly for use as exhaust and/or intake valve on either two- or four-stroke internal combustion engines, inclusive of the pneumatically actuated valve itself, plus forced air distribution and timing mechanisms for controlling the valve. While the assembly is described herein as being pneumatically actuated by means of forced or compressed air, one skilled in the art will recognize that other pressurized gases may be suitable for actuating the valve of the present invention.
The valve 100 includes a hollow, cylindrical body 150 with an upper end 199 and a lower end 101. The lower end 101 is capped by an endplate 102 forming a valve seat 103 that conforms to an annular groove in the housing 200. For example, the valve seat 103 may have a slightly angled (45 degree) surface that mates with a conforming angled surface 208 of the groove (See
With combined reference to
The length of valve 100 is relatively short and wide, compared to conventional internal combustion engine valves which require long thin bodies. The valve length is approximately equal to the thickness of the engine cylinder head in which it is seated. The wide cylindrical body 150 of the present valve 100 makes the valve less likely to suffer the effects of wear and tear as compared to conventional valves.
As discussed above, the hollow housing 200 is defined by an annular groove that receives the valve seat 103. The groove may be an angled surface 208 in the housing 200 that opens into the combustion chamber. This angled groove surface 208 mates with valve seat 103 to ensure that no gases pass into or out of the combustion chamber when the valve 100 is closed. The hollow tubular housing 200 is defined by a smaller diameter section 201 adjacent to a larger diameter section 202. The smaller diameter section 201 is sized to accommodate the valve body 150 with some clearance. The larger diameter section 202 is sized to accommodate the valve collar 198 with some clearance. The adjacent positioning of the two sections (201 and 202) creates a shelf 210 which limits downward motion of the valve, and on which the collar 198 rests when the valve 100 is in the open (down) position.
The embodiment shown in
The above-described two-section housing configuration is important toward actuating the valve pneumatically. When the valve 100 is in the up position (
The valve 100 is actuated by directing forced air into one the “actuation areas” above and/or below the valve collar 198 to force the valve 100 to slide up or down. For valve assemblies in which forced air is used only to close the valve, there is one actuation area beneath the valve collar 198. If compressed air is used to both open and close the valve 100, there are two actuation areas, one above and one below the valve collar 198. In both embodiments, the valve housing 200 contains a hollow air feed channel 207 with one end connected to a forced air source and the other end opening into the shelf 210 beneath the valve collar 198. Thus, the valve 100, particularly the underside of the valve collar 198, is exposed to the channel 207. When the valve is in the open position (100,
For valves 100 with that use forced air to both open and close the valve, the valve housing 200 need not be configured with the housing cap 218 as in
When the pneumatically actuated valve assembly of the present invention is used as an intake valve 100 on a two-stroke internal combustion engine 400 as seen in
Referring to
Similarly,
Exhaust valves typically require substantially more vacuum to open than intake valves. Therefore, the embodiments of the air distribution and timing mechanisms 300 illustrated in
Referring back to
The above-described embodiments of the present invention, inclusive of the pneumatically actuated valve itself, plus forced air distribution and timing mechanisms for controlling the valve, solve the problems and eliminate the disadvantages associated with conventional valves and camshafts on two- and four-stroke internal combustion engines. They provide an assembly that is simple and straightforward, fabricated of strong, durable, resilient materials appropriate to the nature of their usage, and may be economically manufactured and sold. Additionally, implementation of the present invention will increase fuel economy while reducing the emissions of pollutants associated with the operation of conventional two and four stroke internal combustion engines.
Having now fully set forth the preferred embodiment and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.
Engine valves have traditionally been actuated by a cam affixed to a cam shaft. These cam shafts are costly and inefficient. There would be significant commercial value in a wholly pneumatically actuated valve system (by means of supplied compressed air or other pressurized gas). The system would include a pneumatically actuated valve with a valve housing, a forced air distribution and timing mechanism for controlling the valve, and one or multiple air sources to more efficiently regulate the timing of the valve open/close (reciprocation) cycle relative to the engine speed. Such a wholly pneumatically-actuated valve system could be used either as an air intake valve or exhaust valve or both on either a two or four stroke internal combustion engine to increase efficiency and conserve manufacturing cost.
The present application is related to U.S. Pat. No. 6,349,691 issued on Feb. 26, 2002 for an “Automatic, Pressure Responsive Air Intake Valve for Internal Combustion Engine”. It is further related to U.S. Provisional Patent Application No. 60/444,532 for an Energy Efficient Intake Valve Assembly filed on Jan. 31, 2003.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US04/02514 | 1/30/2004 | WO | 7/29/2005 |
Number | Date | Country | |
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60444532 | Jan 2003 | US |