Abstract:
A crankcase inducted self-supercharging four-cycle internal combustion engine that uses cylinder pairs as an induction pump. The cylinder pairs are arranged in a 360-degree crank throw so that both pistons rise and fall together. The system uses two valves and two tubes force air into the crankcase and then into the cylinders in a supercharged mode. It can also operate with both valves closed in a naturally aspirated mode. In this case, air is directed directly into the cylinder through an intake manifold.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation in part of application Ser. No. 09/733,408, filed Dec. 5, 2000, now U.S. Pat. No. 6,338,328. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to self supercharging internal combustion engines and particularly to crankcase inducted self-supercharging four-cycle internal combustion engine. 
     2. Description of Related Art 
     Several patents have been issued relating to the use of the crankcase as an air chamber to enhance combustion air in an engine. These patents cover both two stroke and four stroke engines. For example, U.S. Pat. No. 3,973,532 to Litz uses a sealed crankcase to draw air into the engine. This air is then compressed and stored in a holding tank, where it is drawn into the cylinder on the intake stroke. This compressed air supercharges the fuel mixture before the normal compression stroke. One problem with this design is that it requires a separate sir tank to be added to the engine. Another problem is that it only draws a single charge of air over two of the cycles. While this does provide additional air, it does so inefficiently. 
     U.S. Pat. No. 5,377,634 to Taue teaches another engine that uses the crankcase as a compression chamber for air. Again, the problem is that the chamber is small and the amount of air being compressed and pumped is limited by what one cylinder can pump and compress. U.S. Pat. Nos. 5,230,314, 5,657,724, 4,282,845, and 4,545,346 all teach use of a crankcase as a compression chamber to compress air for combustion. They all suffer from the same volume limitations that limit the amount of air that can be compressed to that produced by one cylinder. 
     U.S. Pat. No. 5,105,775 takes the use of the crankcase combustion chamber in a slightly different direction. Here, the crankcase is divided into a number of sealed chambers. Adjacent chambers are interconnected. Because of the timing differences between the cylinders, this allows one cylinder to charge the other cylinder and vice versa. This then eliminates the need for a separate holding tank, because each cylinder&#39;s crankcase acts as the holding tank for the other. Despite the reduction in equipment needed, the fundamental limitation remains in that the air being compressed remains that volume that can be handled by one cylinder. 
     BRIEF SUMMARY OF THE INVENTION 
     The instant invention is a crankcase inducted self-supercharging four-cycle internal combustion engine that uses cylinder pairs to as an induction pump. The cylinder pairs are arranged in a 360-degree crank throw so that both pistons rise and fall together. The cylinders are synchronized so that when one cylinder is on the intake stroke, the other is on the power stroke. When one cylinder is on the exhaust stroke, the other is on the compression stroke. 
     A two-cycle reed valve is installed on a crankcase inlet port to draw air into the crankcase on the upstroke of the pistons. Since both pistons rise and fall together, each upstroke draws a volume of air equal to the volume of two pistons into the crankcase. When both pistons are on the down stroke, this double volume of air is then moved into a manifold connecting the crankcase to the inlet valves of the cylinders. This air is then pumped into each cylinder alternately on each intake stroke. In this way, it is possible to increase the air available for each cylinder by a factor of two without having to resort to storage tanks or other devices. Moreover, there is no wasted movement in compressing the air because each intake stroke draws in twice the volume of one cylinder. The double volume of air is then delivered into one cylinder, which automatically compresses the air in the cylinder without having to store it or compress it separately. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional front view of a pair of cylinders showing the pistons moving upward as part of the exhaust and compression cycles. 
     FIG. 2 is a cross-sectional front view of a pair of cylinders showing the pistons moving downward as part of the intake and ignition cycles. 
     FIG. 3 is a cross-sectional front view of a pair of cylinders showing the pistons moving upward as part of the compression and exhaust cycles. 
     FIG. 4 is a cross-sectional front view of a pair of cylinders showing the pistons moving downward as part of the ignition and intake cycles. 
     FIG. 5 is a cross-sectional side view of one of the cylinders showing the air control valves set in the naturally aspirated mode. 
     FIG. 6 is a cross-sectional side view of one of the cylinders showing the air control valves set in the supercharged mode during the crankcase-filling stroke. 
     FIG. 7 is a cross-sectional side view of one of the cylinders showing the air control valves set in the supercharged mode during the intake stroke (air being fed from the crankcase). 
     FIG. 8 is a top view of a pair of cylinders showing the air control valves set in the naturally aspirated mode. 
     FIG. 9 is top view of a pair of cylinders showing the air control valves set in the supercharged mode during the crankcase filling operation. 
     FIG. 10 is a top view of one of the pair of cylinders showing the air control valves set in the supercharged mode during the intake stroke (air being fed from the crankcase). 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, a cylinder pair  1  is shown. The cylinder pair  1  has two piston chambers, designated as  2   a  and  2   b . In each piston chamber is a piston, designated as  3   a  and  3   b . Each piston is connected to a crank  5  with connecting rods  4   a  and  4   b . The upper portion of each piston chamber has intake and exhaust valves  6  cams  7  and a spark plug  8 , which are common to the art. Each piston chamber has an exhaust outlet  9  as well. 
     At the lower end of the cylinder pair  1  is a crankcase chamber  10 . As shown, this chamber extends under both pistons. At the center of the crankcase chamber is an inlet port  11  and a reed valve  12 . An inlet tube  13  also rises from the crankcase chamber to the top of the cylinder pair. This tube then bifurcates to form the inlet ports  14  for the each piston chamber. 
     FIG. 1 shows both pistons moving upward. Piston chamber  2   a  is in the exhaust stroke while piston chamber  2   b  is in the compression stroke. At this time, the reed valve  12  opens, allowing air to flow into the crankcase chamber. Because the intake valves are closed, the air is trapped in the crankcase chamber. 
     FIG. 2 shows the next step in the cycle. Here, Piston chamber  2   b  has fired and is in the power stroke. Piston chamber  2   a  is in the intake stroke. As the pistons move downward, they compress the air in the crankcase chamber and, because the intake valve of piston chamber  2   a  is opened, they force the entire volume of air from the crankcase chamber into piston chamber  2   a . This produces a double charge of air in piston chamber  2   a . As shown, the reed valve is closed during this cycle. 
     FIG. 3 shows the upward cycle of the pistons. Here, piston chamber  2   a  is in compression and piston chamber  2   b  is in exhaust. As before, the reed valve opens and a volume of air fills the crankcase chamber. 
     Finally, FIG. 4 shows the next downward cycle, with piston chamber  2   a  having fired and is in the power stroke. Piston chamber  2   b  is in the intake stroke. As the pistons move downward, they compress the air in the crankcase chamber and, because the intake valve of piston chamber  2   b  is opened, they force the entire volume of air from the crankcase chamber into piston chamber  2   b . This produces a double charge of air in piston chamber  2   b . As shown, the reed valve is closed during this cycle. 
     This cycle is then repeated as the engine runs. 
     FIGS. 5-9 show a second embodiment of the invention. In this embodiment, two valves  20  and  25  are inserted into the intake manifold  27  as shown. In this embodiment, an additional inlet tube  13   a  is used, as described below. Note that although the drawings show a pair of vertical tubes  13  and  13   a , any configuration of passageways or tubes can be used to achieve the same purpose. In this embodiment, a first two-way valve  20  and a second two-way valve  25  are used to close the inlet tubes  13  and  13   a  so that all of the intake air is directed into the cylinder from the intake manifold  27  in a naturally aspirated mode of operation. FIGS. 5 and 8 show the naturally aspirated configuration. 
     FIGS. 6,  7 ,  9  and  10  show the system in a supercharged mode. In FIGS. 6 and 9, the valves  20  and  25  are open. As a result, on the upstroke of the cylinder pair (the compression stroke of one piston and the exhaust stroke of the other), air is pulled into the crankcase through the valve  20  and tube  13 . The upward movement of the piston causes the reed valve  12  to open as shown, allowing the charge of air to fill the crankcase. FIGS. 7 and 10 show the supercharged air moving from the crankcase through tube  13   a  into the cylinder. Note that valve  20  prevents any air from entering from the intake manifold  27 . Note also that reed valve  12  is also closed during this operation. In this example, one of the cylinders is in the intake stroke. 
     FIG. 8 shows a top view of the cylinder pair in the naturally aspirated mode. As discussed above, in this configuration, the valves  20  and  25  are closed, allowing air from the crankcase to fill the cylinders through intake manifold  27 . Because one cylinder is on the intake stroke while the adjacent cylinder is on the ignition stroke, the solid arrow represents a double charge of air filling a first cylinder and the dashed arrow represents a second double charge of air filling the second cylinder in the next cycle. 
     FIG. 9 shows a top view showing the valves  20  and  25  in the open (supercharged) position. Here, tube  13  is open to allow combustion air to flow into the crankcase from intake manifold  27 . This occurs during the compression stroke of one cylinder and the simultaneous exhaust stroke of the other cylinder. As before, each arrow represents an air flow during alternate cycles. 
     FIG. 10 shows a top view showing the valves  20  and  25  in the open (supercharged) position. Here, tube  13   a  is open to allow combustion air to flow into the cylinder from the crankcase through tube  13   a . This occurs during the intake stroke of one cylinder and the simultaneous power stroke of the other cylinder. As before, each arrow represents an air flow during alternate cycles. 
     The position of valves  20  and  25  can be set manually, or can be controlled electrically. Moreover, the valves  20  and  25  may also be controlled by a computer to adjust the operation of the engine to match the operating conditions being experienced. Although the valves are both shown operating in concert (either both open or both closed), this is the preferred embodiment. The system can operate with valve  25  operating independently of valve  20 , but that increases control operation and can be expensive and inefficient. 
     The present disclosure should not be construed in any limited sense other than that limited by the scope of the claims having regard to the teachings herein and the prior art being apparent with the preferred form of the invention disclosed herein and which reveals details of structure of a preferred form necessary for a better understanding of the invention and may be subject to change by skilled persons within the scope of the invention without departing from the concept thereof.