Abstract:
Disclosed is a variably timed rotary valve mechanism for controlling the air/fuel intake into and exhaust gases out of an internal combustion engine. There are two rotary valve shafts, one intake and one exhaust, that contain two intake and two exhaust valve ports per engine cylinder. These rotary valve shafts are driven by and synchronized with the engine crankshaft via a conventional timing belt. The timing of each of these rotary valve shafts relative to the crankshaft can be varied individually through hydraulic servomotors under control of a computerized engine management system.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Provisional Patent Application No. 60/283,172 Filed Apr. 12, 2001 
     Applicants: 
     Joseph Samuel Pisano 
     31 Raynor Avenue, Mount Vernon, N.Y. 10552 
     Joseph Michael Pisano 
     31 Raynor Avenue, Mount Vernon, N.Y. 10552 
     REFERENCES CITED 
     U.S. patents: 
     U.S. Pat. No. 4,354,459 Maxey 
     U.S. Pat. No. 4,969,918 Taniguchi 
     U.S. Pat. No. 5,152,259 Bell 
     U.S. Pat. No. 5,706,775 Schweter et al. 
    
    
     BACKGROUND OF INVENTION 
     This invention relates to an improved valve mechanism for an internal combustion engine of the piston and cylinder type. 
     Specifically to an improved rotary valve mechanism employed to control the intake of the air/fuel mixture into the combustion chamber and also exhaust gases out of the combustion chamber. 
     Prior art pertaining to this subject all cites the well-known advantages of rotary valve mechanisms as compared to poppet valve designs. However to date all previous patents were concerned with sealing the intake and exhaust ports from the combustion chamber or varying the valve timing to gain combustion efficiency and emission control. 
     Prior designs have obscured the primary benefit of the rotary valve system. The rotary valve system presented here embodies the essential requirements of a rotary valve system. That is it eliminates as many complicated moving parts as possible and can be mass-produced in an economic manner. 
     The embodiment presented here has very high air/fuel flow characteristics due to the large unobstructed four valve ports per cylinder and essentially has only two moving rotary valve shafts, one intake and one exhaust featuring a variable timing mechanism. 
     SUMMARY OF THE INVENTION 
     The rotary valve system presented herein is used in an internal combustion engine of the piston and cylinder type that has a cylinder encasement such that a block and horizontally split cylinder head would be formed with a plurality of cylinders. 
     There are two rotary valve shafts which are encased in the horizontally split head, one shaft for the intake ports and one shaft for the exhaust ports. Each shaft contains two transverse bores for each engine cylinder. When the intake rotary valve shaft is rotated the ports formed by these bores become aligned with their respective intake passages from the cylinder head into the combustion chamber. This allows the air/fuel mixture to pass into the combustion chamber. When the intake rotary valve rotates such that these transverse ports are perpendicular to the intake passage from the head to the combustion chamber the chamber sealed by the solid portion of rotary valve shaft on its respective combustion chambers seals. Similarly when the exhaust rotary valve rotates such that its exhaust ports are aligned with its corresponding exhaust ports in the cylinder head and the combustion chamber it allows exhaust gases to exit from the combustion chamber. Likewise, when exhaust rotary valve rotates such that its ports are perpendicular to the exhaust ports in the combustion chamber the chamber is sealed. 
     The timing of intake rotary valve shaft and the exhaust rotary on shaft is synchronized with the engine crankshaft by means of a cog belt or timing chain. Further the timing of the intake and exhaust rotary valve shafts are individually variable through the action of individual hydraulic servomotors under the control of a computerized engine management system. This allows for each rotary valve shaft to be advanced or retarded relative to the crankshaft position under the control of the computer driven servomotors. 
     The unobstructed path of the four ports for each cylinder and their large diameters allows for very high airflow quantities in and out of the combustion chambers. Further the contoured shape of the rotary valve shafts allow for the combustion chamber head and to be a very efficient hemispherical configuration. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The structure, operation, and advantages of the preferred embodiment of the invention presented will become apparent upon consideration of the following descriptions taking in conjunction the accompanying drawings. 
     FIG. 1 is a section through the engine from the end view. It shows the engine block with the cylinder walls and piston. This section further shows that the cylinder head is split horizontally for ease of fabrication and maintenance. The cylinder head is shown with the intake and exhaust rotary valves in place. It shows the intake valve in the open position such that the air/fuel mixture can pass into the combustion chamber. If further shows the exhaust rotary valve in the closed position against its valve seal such that the exhaust path out of the combustion chamber is blocked. 
     FIG. 2 shows a side view section through two adjacent cylinders. This view shows you the placement of the rotary valve shaft in the head and the relative position of the shaft to the combustion chamber. It further shows the unique shape of the rotary valve shaft and its position relative to the combustion chamber. The position of the spark plug in this section is omitted for clarity. 
     FIG. 3 shows a view of the engine looking from the top down. It further shows the intake and exhaust rotary valves and their position relative to the cylinders below. It further shows the unique shape of both the intake and exhaust rotary valve shafts and clearly shows two intake ports and two exhaust ports in each rotary valve shaft for each combustion chamber. It further shows the valve ports aligned in the same position as shown in FIG.  1 . 
     FIG. 4 is a perspective view of the rotary valve shaft drive sprocket that would be driven from the engine crankshaft by a cog belt which is not shown. Each rotary valve shaft would be driven by its own sprocket. Each sprocket is advanced or retarded by a hydraulic servomotor and gear mechanism. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Depicted schematically throughout are components commonly known to internal combustion engines such as the engine block, crankshaft, pistons, connecting rods, cylinder heads, combustion chambers and valve ports. Omitted from the schematic drawings depicting this invention are other common internal combustion engine parts such as; water cooling passages throughout the engine block and cylinder heads, piston rings, oil galleys and seals, spark plugs and other common ignition system components. While the description of the preferred embodiment is generally directly toward a four stroke internal combustion engine it is intended that the variable rotary valve system of this invention is equally applicable to a two stroke engine and any other kind of engine that employs intake and exhaust valves including pneumatic compressors and pneumatic actuators. 
     While the descriptions that follow are schematically detailed as a one or two cylinder engine it must be appreciated that this variable rotary valve system is equally applicable to multi-cylinder engine applications. 
     FIG. 1 This is a section from the end view of the engine. It shows the engine block  3  with the cylinder wall  1  and piston  2 . The engine block is joined to the lower section of the cylinder head  5  at the head gasket  4 . Bolts (not shown) would secure the lower section of the cylinder head  5  to the block  3 . The bolts would pass through the block bosses from below into blind treaded holes in the lower half of the cylinder head  5 . In this way the upper half of the cylinder head  8  could be removed without disturbing the seal  4  between the block  3  and the lower head section  5 . The upper half of the cylinder head  8  also has a gasket  6  between the mating surfaces of the upper and lower cylinder head. The upper half of the cylinder head  8  would be secured to the lower half of the cylinder head  5  by bolts (not shown) which would allow the disassembly of the upper head  8  from the lower head  5  for access to the variable rotary valve mechanisms  10  and  11 . 
     The variable rotary valve shaft  10  has a transverse port  18  through it to allow the air/fuel mixture to enter the combustion chamber  14  through the lower head intake port  15  and upper head intake port  7  when in alignment as shown. The variable rotary valve shaft  10  is sealed by seal  20  fixed in the lower portion of the cylinder head  5 . 
     The variable rotary exhaust valve  11  is shown rotated in the closed position and is sealed at the combustion chamber by seal  13 . In this position variable rotary valve  11  does not provide an exhaust flow path through port  16  and port  12 . Both variable rotary valves  10  and  11  would be synchronized and timed to the crankshaft as depicted in FIG.  4 . The spark plug  9  would be fired in the appropriate sequence by an electronic ignition system that is not shown. 
     FIG. 2 shows a side view section through two adjacent cylinders  1  and  1 A. It shows the pistons  2  and  2 A within the cylinder walls  1  and  1 A. In addition to what is described in FIG. 1 this view shows the shape of the variable rotary intake valve shaft  10 . This variable rotary intake valve shaft is supported by bearings  17  which would be oil fed. FIG. 2 further shows that the variable rotary intake valve  10  would have two ports per cylinder  18  and  18 A which when rotated into alignment with cylinder head ports  15  and  15 A would allow the air/fuel mixture to pass into the combustion chamber  14 . Although not shown the variable rotary exhaust valve shaft would be configured in the same fashion. 
     As can be seen by looking at FIG.  1  and FIG. 2 when ports  18  and  18 A of the variable rotary intake shaft  10  are rotated into alignment with ports  15  and  15 A and ports  7  and  7 A (Not shown) an unrestricted airflow path is provided into the combustion chamber. This flow path configuration is superior to and in part what differentiates this design from other rotary valve configurations. The adjacent cylinder  1 A shows piston  2 A near the top of its travel and ports  22  and  22 A through the variable rotary valve shaft out of alignment with ports  23  and  23 A in the combustion chamber  14 A thus sealing the combustion chamber  14 A as would be common on a compression stroke. 
     FIG. 3 This drawing is a Plan view showing two adjacent cylinders  1  and  1 A and both the intake and exhaust variable rotary valve shafts  10  and  11  sitting in the lower half of cylinder head  5  supported by bearings  17  and  17 A. Further shown is the configuration of each variable rotary valve shaft  10  and  11  above and adjacent to the two cylinders  1  and  1 A and communicating with the combustion chambers  14  and  14 A (shown in FIG. 2) through the ports  18  and  18 A and ports  22  and  22 A in the variable intake rotary valves shaft and through ports  25  and  25 A and  26  and  26 A in the variable exhaust rotary valve shaft. 
     The rotary intake valve  10  when rotated communicates with cylinder  1  through ports  18  and  18 A. Similarly ports  22  and  22 A when in alignment will allow the unrestricted flow of the air/fuel mixture into cylinder  1 A. The rotary exhaust valve  11  when rotated into the proper position allows ports  25  and  25 A to pass exhaust gases from cylinder  1  after combustion is complete. 
     FIG. 4 This drawing is a perspective view of the variable timing mechanism that advances or retards the timing of the intake rotary valve shaft and the exhaust rotary valve shaft relative to the position of the engine crankshaft. 
     For simplicity FIG. 4 depicts only the variable intake rotary valve shaft and mechanism to advance or retard the valve timing relative to the engine crankshaft. The exhaust rotary valve mechanism is essentially identical in form and function. As shown in FIG. 4 the intake rotary valve shaft “C” would be attached to and controlled by its respective rotary valve shaft sprocket “A”. The rotary valve shaft sprocket “A” is driven by a cog belt not shown. The sprocket “A” is attached to the rotary intake valve shaft “C” by gear coupling “B”. The gear coupling “B” is moved forward or backward axially on the splined shaft “C” of the rotary valve intake shaft by a hydraulic servomotor (not shown). This servomotor is actuated under the control of the electronic engine management system. The movement of coupling “B” on splined shaft “C” causes the sprocket “A” to advance or retard the rotary valve shafts due to the action caused by helical gear “B”. This control of the rotary valve timing will allow the engine management system to automatically adjust engine power and emissions.