This invention relates to internal combustion engines and is particularly concerned with two-cycle engines of the opposed piston type wherein a pair of pistons operate oppositely in cylinders that are in communication with each other and reciprocating ported sleeves surround each piston. It is a general object of this invention to provide an internal combustion engine of higher horsepower rating per pound of engine weight and particularly a two-cycle engine that is capable of being supercharged.
U.S. Pat. No. 3,084,678 (“the '678 patent”) discloses an internal combustion engine of the type described above having opposed pistons and reciprocating sleeves to alter the porting characteristics of the engine. The disclosure of the '678 patent is incorporated herein in its entirety by this reference.
The engine of the '678 patent comprises opposed pistons having reciprocating sleeves around each piston, wherein related pistons and sleeves are connected to the same crankshaft. This resulted in a configuration that does not permit for adjustment of the timing of the sleeves with respect to the pistons to maximize efficiency and power. Thus, once an engine is constructed pursuant to the '678 patent, the timing of the movement of the reciprocating sleeves is fixed with respect to the movement of the related pistons.
Accordingly, it is an object of present invention to provide an engine having reciprocating sleeves wherein the reciprocating sleeves are connected to a shaft separate and distinct from the crankshaft that moves the related pistons. It is another object of this invention to provide a means to advance or retard the timing of the motion of the reciprocating sleeve shaft with respect to the motion of the piston crankshaft.
It is a further object of this invention to provide a piston connecting rod that is streamlined to generate less resistance and windage during operation of the engine.
It is still another object of this invention to provide for an engine that is entirely of flat plate and tube construction using only tools found in a machine shop, i.e., a lathe, a mill, a drill press, and a power saw.
The present invention fulfills these objects and provides other related advantages.
In accordance with the invention, an internal combustion engine having reciprocating piston sleeves is realized comprising an engine block with a pair of cylinders, each cylinder having an intake port, an exhaust port and two linearly opposing pistons connected to two opposing crankshafts. A pair of piston sleeves are reciprocatingly mounted in each cylinder, one piston sleeve around each piston. Each piston sleeve is connected to one of two eccentric shafts that run parallel and adjacent to each crankshaft. The piston sleeves have ported slots in communication with either the intake ports or the exhaust ports of each cylinder. The eccentric shafts are mechanically connected to the crankshafts such that they move in unison.
In the preferred embodiment, the piston sleeves are connected to the eccentric shafts by two sleeve connecting rods. The sleeve connecting rods are fixed to the piston sleeves by a lateral barring shaft. The piston sleeves also include a re-enforcing band to reduce twisting and torsion forces.
In one embodiment the eccentric shafts are connected to the crankshafts by means of gears in a 1:1 ratio. In the preferred embodiment, the eccentric shafts are connected to the crankshafts by a sprocket and chain assembly in a 1:1 ratio. The sprocket and chain assembly may include a computer controlled timing guide on the chain to advance or retard the movement of the eccentric shaft with respect to the crankshaft. The computer controlled timing guide comprises a slide and an actuator cylinder connected to the slide. The actuator cylinder may directly connected to the slide or connected to a slide by means of a lever.
The pistons are connected to the crankshaft by means of a piston connecting rod. In the preferred embodiment, the piston connecting rod has a streamlined profile, i.e., either a pointed oval or a flattened diamond cross-section. The top of each piston head may have a curved concave shape or a stepped concave shape depending upon the fuel to be combusted.
The back of the engine includes a drive gear case having a drive gear connected to one or more idler gears which are in turn connected to crankshaft gears. In addition, the front of the engine may have one or more accessory gears connected to the crankshaft gears. The idler gears and accessory gears may be hunting tooth gears. The drive gear, idler gears, crankshaft gears and accessory gears may be spray lubricated.
a is a schematic representation of the computer controlled timing guide and chain and sprocket assembly connecting the crankshaft to the eccentric shaft in the present invention.
b is a schematic representation of an altered embodiment of the computer controlled timing guide and chain and sprocket assembly connecting the crankshaft to the eccentric in the present invention.
a is a cross-section of an alternate embodiment of a piston connecting rod of the present invention taking along line 16-16 of
a is a cross-section of an alternate embodiment of a piston connecting rod of the present invention taking along line 17-17 of
The present invention is directed toward an internal combustion engine 10. More specifically, it is directed toward an internal combustion two-cycle engine 10 having opposed pistons 12 and reciprocating piston sleeves 14 surrounding each of the pistons 12; the pistons 12 and piston sleeves 14 each actuated by separate shaft 16, 18. While the following describes a two-cycle, opposed piston engine 10 having four cylinders 26, the principals of this invention are applicable to two- or four-cycle engines having any number of cylinders.
As shown in
Each pair of intake 20 and exhaust ports 22 is in communication with one of the cylinders 26. The spark plug 30 and fuel injections 28 may be configured at an angle such that the injected fuel intersects the ignition spark just inside the cylinder 26 for both the top and bottom of the engine block 24. In the preferred embodiment, the spark plug 30 and fuel injector 28 may be parallel and oppositely configured with the fuel injector 28 and spark plug 30 on the other side of the engine block 24. In this configuration, the fuel injected from the top of the engine block 24 would intersect with the spark from the spark plug 30 on the bottom of the engine block 24. Similarly, the fuel injected from the bottom of the engine block 24 would intersect with the spark from the spark plug 30 on the top of the engine block 24. This configuration results in better performance of the engine 10 because the combustion is more evenly distributed throughout the cylinder 26.
As shown in
The idler gears 56 may have one more or one less tooth than the adjacent crankshaft 54 or final drive gears 52. This is referred to as a hunting tooth gear. The purpose of this configuration is so that every tooth in the hunting tooth or idler gears 56 contacts every tooth in the crankshaft 54 and final drive gears 52. This assures even wear on all teeth on all gears and results in a much longer gear life. In addition, all of these gears have extra wide teeth, which decreases stress and also reduces friction. In the preferred embodiment, the gears in the power gear case 50 are spray lubricated and do not run in oil. This also increases the life span of the gears by reducing friction and heat. The engine 10 of the present invention will function without the above improvements to the gears of the power gear case 50.
The accessory gear case 40 may have gears similar to the gears in the power gear case 50. As shown in
A shown in
All of the intake pistons 12a are driven by a first crankshaft 16a and all of the exhaust pistons 12b are driven by a second crankshaft 16b. As depicted in
For ease of reference, the middle of each cylinder where two pistons meet or the portion of any component toward the middle of each cylinder will be referred to as the top of the cylinder or component. Conversely, the portion of each cylinder or component adjacent each crankshaft will be referred to as the bottom of the cylinder or component.
As shown in
An eccentric shaft 18 runs parallel and adjacent to each crankshaft 16 and may be located above or below the crankshaft 16. In the preferred embodiment, the eccentric shaft 18 is located above the crankshaft 16, i.e., nearer the top of the cylinder 26. Each eccentric shaft 18 comprises portions of its length that include lobes which offset that portion of the shaft from its axis of rotation. Each piston sleeve 14 is connected to the eccentric shaft 18 nearest its bottom end. In the preferred embodiment, each piston sleeve 14 is connected to the eccentric shaft 18 by two sleeve connecting rods 34. However, the engine 10 will operate if only one sleeve connecting rod 34 is used. The use of two sleeve connecting rods 34 prevents undesirable twisting or torsion forces on the piston sleeve 14. In the preferred embodiment, the bottom of each piston sleeve 14 includes a lateral bearing shaft 36 affixed to a side of the piston sleeve 14 and parallel to the eccentric shaft 18. The lateral bearing shaft 36 provides a secure place to attach the sleeve connecting rods 34 to the piston sleeves 14. In addition, the bottom of each piston sleeve 14 has a strengthening band 38 around its perimeter to further stabilize the piston sleeve 14 against twisting and torsion forces. The lobes of the eccentric shaft 18 cause the piston sleeves 14 to reciprocate within the cylinder 26 in timed relationship with each piston 12 to vary the opening and closing of the intake 20 and exhaust ports 22 as will be described more fully below.
The eccentric shafts 18 are driven by means of a mechanical connection between each eccentric shaft 18 and the adjacent crankshaft 16. In one embodiment, adjacent crankshafts 16 and eccentric shafts 18 are geared together in a 1:1 ratio by using gears 42, 44 as shown in
In the preferred embodiment, adjacent crankshafts 16 and eccentric shafts 18 include sprockets 70, 72 that are connected by a slack chain loop 74 as shown in
As shown in
In operation this two-cycle engine 10 develops a higher break mean effective pressure than comparable four-cycle engines. To accomplish this, the engine has blow through cylinders 26 with no spring operated parts. The pistons 12 themselves act as valves by opening and closing the intake 20 and exhaust ports 22. Blow through means that the exhaust ports 22 open just prior to the intake ports 20 in a given cycle. As air flows in the intake ports 20, it forces residual gasses out the exhaust ports. This purges the cylinder 26 from end to end. As the cycle continues the exhaust ports 22 close while the intake ports 20 remain open. Since the intake ports 20 remain open, they permit the inflow of additional air to increase the internal pressure in the cylinder 26, i.e., super charging the engine. The intake ports 20 then close and the cycle returns to the beginning. The following describes a preferred embodiment of how the engine operates. A person having ordinary skill in the art will recognize that variances in the positions of the pistons 12 and the piston sleeves 14 and when the intake ports 20 and exhaust ports 22 open and close will still achieve the objects of this invention.
The reciprocating, ported piston sleeves 14 adjust when the intake ports 20 and the exhaust ports 22 open and close and the computer control guide 80 can advance or retard the timing of the eccentric shaft 18 with respect to the crankshaft 16. Advancing or retarding the timing can change the relative positions of the piston sleeves 14 with respect to the pistons 12 and adjust the opening or closing of the intake ports 20 and the exhaust ports 22. This can cause the intake ports 20 to open sooner or later than 40 degrees before bottom dead center and close sooner or later than 70 degrees after bottom dead center to maximize power and efficiency. Similarly, it can cause the exhaust ports 22 to open sooner or later than 60 degrees before bottom dead center and close sooner or later than 40 degrees after bottom dead center for the same reasons.
The top of the pistons 12 may have a concave cross section depending upon the type of fuel that is combusted in the engine 10. For diesel fuel, the top of the piston 12 would have an angled or stepped concave cross-section 58, as depicted in
The engine 10 is designed to be built using flat plate construction. This means that the entire engine 10 is made of flat plate elements that are bolted, screwed and/or welded together in the three major elements: (1) crankcase or block 24; (2) cylinder port areas 26, 20, 22, and (3) firing chambers 28, 30 at the middle of the cylinders 26. The firing chambers are where the spark plug 30 and fuel injectors 28 are located on both the top and bottom sides of the engine block 24. All parts of the engine 10 may be constructed in a machine shop using a lathe, a mill, a drill press and a power saw. The engine 10 structure can be constructed from flat plate aluminum or similar materials, as well as, steel and/or stainless steel. Aluminum or other similar materials may also be used for the cylinders 26 and the piston sleeves 14. Materials that have been subjected to deep anodizing and treatment will also work in this engine 10. Quite a number of new materials are also being introduced in the industry, i.e., carbon composites, carbon fiber and ceramic materials, for high-temperature, high-strength applications that would be useful in the present engine 10.
The resulting engine 10 is an elongated box with no structural curves resulting in all straight-line stresses. The straight-line box structure of the engine block 24 renders very rugged diesel engines that are lighter than existing aircraft engines. The engine 10 design has no size limitations and may be made large enough to power ocean liners or small enough for outboard motors or motorcycles. As an engine 10, this design excels for vibration free, smooth running and power beyond comparable existing designs.
The interaction between the piston 12 and piston sleeves 14 with respect to the intake 20 and exhaust ports 22 provides for 360 degrees of auto growth porting allowing the highest air-flow ability of any engine 10. Auto growth porting means that the sizes of the intake 20 and exhaust ports 22 are effectively increased or decreased depending upon the interaction of the piston 12 and the piston sleeve 14 with the ports 20, 22. As the pistons 12 uncover the ports 20, 22, the piston sleeves 14 are moving opposite the pistons 12, thereby modifying the flow of incoming air and the outflow of exhaust gasses. As an added bonus, when the pistons 12 stop at the end of each stroke, the piston sleeve 14 is still moving. This keeps the pistons 12 on a constant film of oil resulting in nearly zero wear and very low friction.
Although several embodiments of the invention have been described in detail for purposes of illustration, various modifications of each may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not limited except by the dependent claims.
Number | Name | Date | Kind |
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2397752 | Rustad | Apr 1946 | A |
3084678 | Lindsay | Apr 1963 | A |
6152101 | Parsi | Nov 2000 | A |
6158409 | Gillespie et al. | Dec 2000 | A |
Number | Date | Country | |
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20070028866 A1 | Feb 2007 | US |