Abstract:
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.

Description:
BACKGROUND OF THE INVENTION 
   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 &#39;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 &#39;678 patent is incorporated herein in its entirety by this reference. 
   The engine of the &#39;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 &#39;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. 
   SUMMARY OF THE INVENTION 
   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. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an elevated perspective view of the engine of the present invention. 
       FIG. 2  is a top view of the engine of the present invention. The bottom view is a mirror image of the top view. 
       FIG. 3  is a sectional view of the engine of the present invention taking along line  3 - 3  of  FIG. 1 . 
       FIG. 4  is a sectional view of the engine of the present invention taking along line  4 - 4  of  FIG. 1 . 
       FIG. 5  is a sectional view of the engine of the present invention taking along line  5 - 5  of  FIG. 1 . 
       FIG. 6  is a sectional view of the engine of the present invention taking along line  6 - 6  of  FIG. 5 . 
       FIG. 7  is a sectional view of the accessory gears of the present invention taking along line  7 - 7  of  FIG. 5 . 
       FIG. 8  is a sectional view of a cylinder of the present invention taking along line  8 - 8  of  FIG. 5 . 
       FIG. 9  is a sectional view of a cylinder of the present invention taking along line  9 - 9  of  FIG. 5 . 
       FIG. 10  is a depiction of a cylinder of the engine of the present invention shown at 60 degrees before bottom dead center. 
       FIG. 11  is a depiction of a cylinder of the engine of the present invention shown at 40 degrees before bottom dead center. 
       FIG. 12  is a depiction of a cylinder of the engine of the present invention shown at 40 degrees after bottom dead center. 
       FIG. 13  is a depiction of a cylinder of the engine of the present invention shown at 70 degrees after bottom dead center. 
       FIG. 14   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. 
       FIG. 14   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. 
       FIG. 15  is a cross-section of one of the piston connecting rods of the engine of the present invention. 
       FIG. 16  is a cross-section of the piston connecting rod taking along lines  16 - 16  of  FIG. 15 . 
       FIG. 16   a  is a cross-section of an alternate embodiment of a piston connecting rod of the present invention taking along line  16 - 16  of  FIG. 15 . 
       FIG. 17  is a cross-section of the piston connecting rod taking along line  17 - 17  of  FIG. 15 . 
       FIG. 17   a  is a cross-section of an alternate embodiment of a piston connecting rod of the present invention taking along line  17 - 17  of  FIG. 15 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   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  FIGS. 1 and 2 , the engine  10  of the present invention has an engine block  24  of a box shape constructed exclusively from flat plate materials. In a four cylinder  26  engine  10 , there are four intake ports  26  and four exhaust ports  22  in series on the top side of the block  24 . In the center of the engine block  24 , between the series of intake  20  and exhaust ports  22  are access points at each cylinder  26  for a fuel injector  28  and spark plug  30 . The underside (not shown) of the engine block  24  is a mirror image of the top side. 
   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  FIGS. 3-5  and  7 , the front of the engine block  24  has a case for accessory gears  40  and the back of the engine block has a case for power gears  50 . The power gear case  50  has an output gear  52  to drive the transmission or other system in which the engine  10  is mounted. As shown in  FIGS. 3 and 4 , the power gear case  50  consists of a gear on the end of each crankshaft  54 , idler gears  56 , and a final drive or output gear  52 . The crankshaft gears  54  and final drive gear  52  each have the same number of teeth. 
   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  FIGS. 3 ,  4  and  7 , the accessory gears may consist of a gear on the end of each crankshaft  42 , a gear on the end of each eccentric shaft  44 , idler gears  46 , and a main accessory gear  48 . The gears on the end of each eccentric shaft  44  may be offset as shown in  FIGS. 3 and 7 . Alternatively, as shown in  FIG. 4 , the gears in the accessory gear case  40  may consist of a gear on the end of each crankshaft  42 , idler gears  46 , and a main accessory gear  48 . In either configuration, the idler gears would be hunting tooth gears. The gears of the accessory gear case  40  may include the same extra wide gear teeth and spray lubrication improvements discussed above for the power gear case  50 . 
   A shown in  FIGS. 3-6 , each cylinder  26  in the engine  10  contains two pistons  12 , one on the intake side and one on the exhaust side. In  FIG. 6 , the ports, both intake  20  and exhaust  22 , extend upwards and downwards from the piston cylinder  26 . The cross-section shown in  FIG. 6  is a mirror image of the cross-section that would be taken in the opposite direction of line  6 - 6  in  FIG. 5 . 
   All of the intake pistons  12   a  are driven by a first crankshaft  16   a  and all of the exhaust pistons  12   b  are driven by a second crankshaft  16   b . As depicted in  FIG. 5 , each of the four intake pistons  12 A and four exhaust pistons  12 B are connected to their respective crankshafts  16 A,  16 B at positions offset from one another by 90 or 180 degrees. For example, the piston in the first cylinder and the piston in the fourth cylinder are offset from each other by 180 degrees. The piston in the second cylinder and the piston in the third cylinder are offset from one another by 180 degrees. The piston in the first cylinder is offset by 90 degrees from each of the pistons in the second and third cylinders. Similarly, the piston in the fourth cylinder is offset by 90 degrees from each of the pistons in the second and third cylinders. This results in a piston firing order of 1-3-4-2. Alternatively, the pistons may fire in the order of 1-2-4-3. The connection of the pistons to crankshaft and the firing order of pistons should be configured such that there is not more than a 90 degree difference between any sequential firing of the pistons and any sequential firing of pistons does not skip more than one cylinder. 
   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  FIGS. 3-4 , around each piston  12  in each cylinder  26  is a piston sleeve  14 . Each piston sleeve  14  is a circular cylinder that surrounds each piston  12 . Each piston sleeve  14  has slotted openings  32  that align at least partially with either the intake ports  20  or exhaust ports  22  in each cylinder  26 . The slotted openings  32  act to vary the porting characteristics of each cylinder  26  by altering when the intake  20  and exhaust ports  22  open and close as will be described below. 
   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  FIG. 3 . In an alternate embodiment, adjacent crankshafts  16  and eccentric shafts  18  may include operating gears  60 ,  66  that are connected to a common gear  62  as shown in  FIG. 4 . These gears  60 ,  66  are also configured in a 1:1 ratio. The common gear  62  may be connected to an actuator  64  configured to advance or retard the timing of the eccentric shaft  18  with respect to the crankshaft  16 . 
   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  FIGS. 14A and 14B . As with the gears  42  and  44  or  60  and  66 , the sprockets  70 ,  72  are preferably in a 1:1 ratio. As shown in  FIGS. 14A and 14B , a computer controlled guide  80  consisting of a slide  82  and actuator cylinder  84  may be connected to the chain loop  74 . The actuator cylinder  84  may comprise a hydraulic or other mechanism and may be directly connected to slide  82  or may be connected to the slide by a lever  86 . The position of the slide  82  with respect to the chain loop  74  may be varied by the actuator cylinder  84 . In this way, the computer controlled guide  80  may advance or retard the timing of the eccentric shaft  18  with respect to the crankshaft  16 . Advancing or retarding the timing of the eccentric shaft  18  with respect to the crankshaft  16  may be done to improve the efficiency or power of the engine  10  by altering the porting characteristics as will be described more fully below. 
   As shown in  FIG. 15 , the bottom of each piston  12  is connected to its adjacent crankshaft  16  by a piston connecting rod  90 . In the preferred embodiment, as shown in  FIGS. 16 ,  16 A,  17  and  17 A, the piston connecting rods  90  have a streamlined shape, either a pointed oval cross-section ( FIGS. 16 and 17 ) or a flattened diamond cross-section ( FIGS. 16A and 17A ). The narrow points  92  of each piston connecting rod  90  are aligned with the top and bottom of the engine block  24  (NOTE: not the top and bottom of the cylinders). The streamlined piston connecting rods  90  reduce windage within the crank case or engine block  24 . These types of cross-sections leave ample room for an oil pressure hole  94  through the connecting rod  90  to the piston wrist pin  96  and spray holes (not shown) for cooling the pistons  12 . Such configuration is not possible with prior art connecting rods either H-beam or I-beam, in use in some current engine designs. This streamlined design for piston connecting rods  90  may be used in other types of engines, separate and apart from this engine  10 . 
   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. 
     FIG. 8  depicts the relative positions of the pistons  12  and piston sleeves  14 , as well as the status of the intake ports  20  and exhaust ports  22  for one cylinder  26  when the pistons  12  in that cylinder  26  are at top dead center.  FIG. 10  depicts the relative positions of the pistons  12  and piston sleeves  14 , as well as the fact that that the exhaust port  22  opens when the pistons  12  in a cylinder  26  are at 60 degrees before bottom dead center.  FIG. 11  depicts the relative position of the pistons  12  and piston sleeves  14  and the fact that both the intake ports  20  and exhaust ports  22  are open when the pistons  12  in a cylinder  26  are at 40 degrees before bottom dead center.  FIG. 9  depicts the relative positions of the pistons  12  and piston sleeves  14 , as well as the status of the intake ports  20  and the exhaust ports  22  when the pistons in a cylinder  26  are at bottom dead center.  FIG. 12  depicts the relative positions of the pistons  12  and piston sleeves  14 , as well as the fact that the intake port  20  remains open while the exhaust port  22  closes when the pistons  12  in a cylinder  26  are at 40 degrees after bottom dead center.  FIG. 13  depicts the relative positions of the pistons  12  and piston sleeves  14 , as well as the fact that both the intake ports  20  and exhaust ports  22  are closed when the pistons  12  in a cylinder  26  are at 70 degrees after bottom dead center. The crankshafts  16  and eccentric shafts  18  continue their rotation around until the pistons  12  in a cylinder  26  reach top dead center again and then begin the cycle all over. 
   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  FIG. 5 . If the fuel is gasoline, the top of the piston  12  would have a semi-circular concave cross-section  68 , also as depicted in  FIG. 5 . 
   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.