Abstract:
An internal four-cycle combustion engine with a hub that acts as a rotary valve that rotates in relation to at least one piston is provided. The rotary valve hub includes passageways to provide for fuel/air intake, exhaust, and coolant as well as an ignition devise and services all cylinders around it. Each piston compresses inward toward the hub and is actuated by a cam affixed to the hub. The cam may be articulated to provide the engine with variable displacement and variable compression ratio.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This design has been developed from the Stotler Radial Rotary Piston Engine patent application Ser. No. 10/245,968 to provide variable engine displacement and variable compression ratio. This patent details the use of a cam to drive the pistons instead of crankshafts as presented in the seventh claim of the aforementioned patent application. The use of a cam to actuate the pistons instead of crankshafts provides several advantages. The piston position is controlled by the shape of the cam and not the circular motion of a crankshaft. The cam profile can position the piston anywhere with regards to the rotational position of the hub. A simple articulation of the cam mechanism results in varying the engine displacement by changing the length of the strokes. The dimensions of the combustion chamber can be left constant so this also has the effect of varying the compression ratio of the engine. The result is an engine that can be very fuel-efficient and clean burning during partial throttle but provide very high power output when desired.  
       SUMMARY OF THE INVENTION  
       [0002]     The present invention comprises an internal combustion engine with at least one piston and a hub that acts as a rotary valve. Multiple pistons, six in this example, are arranged radially around the central hub and compress inward toward the hub. The hub acts as a single rotary valve that services all the pistons around it. The rotary valve hub includes passageways to provide for fuel/air intake, exhaust, and coolant as well as an ignition devise. The pistons are actuated by a cam that is affixed to the hub. As the hub rotates once in relation to the piston cylinder it opens to provide a fuel air mixture during the intake stroke of the piston, seals the cylinder for the compression stroke, ignites combustion, remains sealed for the power stroke and opens the cylinder to allow gasses to escape during the exhaust stroke. The use of a cam to actuate the pistons in this radial design allows the four piston strokes to vary in length. For instance, the compression stroke can be shorter or longer than the combustion stroke. In addition the top dead center combustion chamber volume can differ from the top dead center chamber volume between valve actuation. In fact the term top dead center no longer need apply to this system as the piston position is controlled by the shape of the cam and not the circular motion of a crankshaft. Changing the cam profile during operation can be done if the cam is split into two halves. A simple articulation of the cam halves results in varying the engine displacement. This also has the effect of varying the compression ratio of the engine.  
       BRIEF DESCIPTIONS OF THE DRAWINGS  
       [0003]     The accompanying drawings illustrate the invention and in such drawings:  
         [0004]      FIG. 1  is a view of the engine of the present invention.  
         [0005]      FIG. 2  is a side view of the engine.  
         [0006]      FIG. 3  is a perpendicular cross sectional view of  FIG. 2  through broken line A.  
         [0007]      FIG. 4  is similar to  FIG. 2  except some of the outer housing has been removed.  
         [0008]      FIG. 5  is a perpendicular cross sectional view of  FIG. 4  through broken line A.  
         [0009]      FIG. 6  is similar to  FIG. 4  except that the hub assembly has been rotated.  
         [0010]      FIG. 7  is a perpendicular cross sectional view of  FIG. 6  through broken line A.  
         [0011]      FIG. 8  is a view of the hub and cam assembly.  
         [0012]      FIG. 9  shows the other side of the hub and cam assembly.  
         [0013]      FIG. 10  is a view from the front of the engine.  
         [0014]      FIG. 11  is a perpendicular cross sectional view of  FIG. 10  through broken line B.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]      FIG. 1  is a view of the engine of the present invention with six cylinders. This view shows the appearance of the engine from the outside. Notation  1  is the passageway where the air-fuel mixture enters the engine. The rest of the induction system is not depicted and is not included in this patent. Notation  2  is the passageway where the exhaust exits the engine. The rest of the exhaust system and drive train is not depicted and is not included in this patent.  
         [0016]      FIG. 2  is a side view of the engine. Item  3  is the front structure of the engine. The primary function of this structure is to mount the front main bearing of the engine. It also provides a mounting point for the intake manifold, alternator, water pump, and other accessories (all not shown). Item  4  is a fan belt groove and is part of the hub assembly that rotates in conjunction with the hub. These two grooves are provided to drive any accessories as needed. Item  5  is a timing wheel that is used for the ignition system (not shown). Item  6  is a passageway that allows air to cool the hub. As the hub spins, centrifugal action draws airs through the engine and out these openings much like a vented disk brake. Item  7  is the outer housing of the engine and also functions to hold the engine oil. Item  8  is the exhaust passageway. Item  9  provides a mount for the rear main bearing as well as the clutch and transmission (not shown). Item  10  is the crank shaft. The flywheel (not shown) would mount to this. Item  11  is the exhaust manifold.  
         [0017]      FIG. 3  is a perpendicular cross sectional view of  FIG. 2  through broken line A and perpendicular to the axis of rotation. Item  12  is the outer housing (same as Item  7 ). Item  13  is the outer bearing attached to the piston. This consists of a wheel mounted on a high-speed ball bearing. Item  14  is the inner bearing attached to the piston. This consists of a wheel mounted on two high-speed ball bearings. The inner bearings will be subjected to the far greater forces of combustion so they are made larger and stronger. Item  15  is the cam which rotates in conjunction to the hub assembly. The inner and outer piston bearings ride on the cam. As the cam/hub assembly rotates, the bearings transmit linear motion to the pistons and vise versa. This cam is divided into two halves and is shown here in the expanded position. The articulation of these two cam halves allows for the variable displacement of this engine. Item  16  is the engine block. Item  17  is a cylinder seal that is spring loaded against the hub. This acts similar to a head gasket and rides against the hub and floats concentric to the cylinder liner. The tightness of this seal is determined by the strengths of the springs and the compression ratio. Compression in the cylinder acts to tighten this seal. Item  18  is the piston. Item  19  is the spark plug. This is mounted within the hub assembly. The spark plug is seen here positioned to allow for a large timing advance. If more spark energy or a greater range of spark advance is desired additional spark plugs or glow plugs can be added. Item  20  is one of many cooling fins in the hub. Air pulled through these fins act to cool the hub. Notation  21  shows the cylinder chamber during the combustion stroke. Notation  22  shows a coolant passageway through the engine block. Notation  23  shows the exhaust passageway through the hub. Notation  24  shows the intake passageway through the hub.  
         [0018]      FIG. 4  is a view similar to  FIG. 2  except some of the outer housing has been removed to reveal some of the inner components. Item  25  is the front main bearing of the hub. Item  26  is a bolt to hold together the outer housings. Item  27  is an exhaust manifold bolt. Item  28  is a transmission mount bolt. Item  29  is the rear main bearing for the hub assembly. Item  30  is one of the coolant passageways for the block. The second coolant passageway is located directly behind item  30  in this view. Item  31  is a component that maintains the alignment of the piston within the cylinder.  
         [0019]      FIG. 5  is a perpendicular cross sectional view of  FIG. 4  through broken line A and perpendicular to the axis of rotation.  FIG. 5  shows the cam in the position that results in the engine&#39;s minimum displaces where as  FIG. 3  shows the cam expanded in the position of maximum engine displacement. Notation  32  shows the cylinder chamber at the end of the intake stroke. Notation  33  shows where the two halves of the cam contact each other when the engine is at minimum displacement. Item  34  is part of the hub assembly that has been revealed from the movement of the cam half inward. Notation  36  shows the cylinder chamber at the end of the combustion stroke. When compared to  FIG. 3  the stroke of the pistons of notations  32  and  35  has been reduced by the same amount as the displacement seen at  34 . The articulation of the cam halves does not alter the piston top dead center position at notation  33 . The height of the combustion chamber is always constant. Increasing the engine displacement while maintaining the same combustions chamber dimensions has the effect of increasing the compression ratio. The use of a cam to move the pistons allows the lengths of the intake stroke and combustion stroke to be different. This can be seen by comparing the piston positions at notations  32  and  35 . Notation  36  shows one of the air passageways through the center of the hub.  
         [0020]      FIG. 6  is similar to  FIG. 4  except that the hub assembly has been rotated relative to the block. Item  37  is one of cam bolts and can now be seen.  
         [0021]      FIG. 7  is a perpendicular cross sectional view of  FIG. 6  through broken line A and perpendicular to the axis of rotation. Notation  38  is the cylinder chamber during the compression stroke. Notation  39  is the cylinder chamber at top dead center and the beginning of the combustion stroke. Notation  40  is the cylinder chamber during the combustion stroke. Notation  41  is the cylinder chamber during the exhaust stroke with the cylinder opened to the exhaust passageway of the hub. Item  42  is the piston in the top dead center position. The cam profile allows the top dead center piston position to be different at Item  42  to that at notation  39  (the combustion position). The exhaust stroke can be set to empty the cylinder to near zero volume without any valve overlap. The flexibility of the cam to position the piston in any desired position relative the hub allows this design to offer many tuning options. In addition to independently setting stroke lengths the acceleration of the piston between end points can be set. The pistons can also be held at the end of the stroke for a period of time if desired.  
         [0022]      FIG. 8  is a view of the hub and cam assembly. The bolts holding the cam halves together have been extracted and revealed. Item  43  is one of four bolts used to mount springs within the cam assembly. These four springs (item  44 ) act to hold the cam halves (item  45 ) together in the minimum displacement position. During engine operation three other forces with also be acting on the cam halves. Centrifugal forces will act to expand the cam halves as the rpm of the engine increases. So after the rpm reaches a certain value, the cam halves will be held in the maximum displacement position. The forces within the cylinders will also act to expand or close the cam halves corresponding to throttle position. With the throttle closed, the engine vacuum created in the intake cylinder will act to close the two cam halves together. As the throttle is opened, the reduction in vacuum in the intake cylinders and the increase in combustion pressures in the expansion cylinders will act to separate the cam halves and increase the engine displacement. The strength of the cam springs will determine how the engine displacement will respond to rpm and throttle inputs.  
         [0023]     Item  46  connects the hub assembly with the two cam halves. Item  47  is the hub with many of its passageways in view. Item  48  is one of two gears that make the cam halves expand symmetrically and helps to keep them in alignment. Linking these two gears with another gear in the location of Item  46  (but not shown) would ensure that the two cam halves would expand symmetrically. Item  49  is a bolt in connection with item  46 . Notation  50  shows how the cam halves are intermeshed at the point of cam half separation. The cam surface interlocks here to provide a smooth surface for the piston bearings to ride upon during cam articulation. The length of these interlocking fingers determines how much displacement can be added to the engine. Item  51  is a non-spring loaded bolt. Its function is to limit the expansion of the cam halves and maintain their alignment. Notation  53  shows the cam surface where the inner piston bearings ride. Notation  54  shows the cam surface where the outer piston bearings ride.  
         [0024]     Notation  52  shows the passageway where air enters the hub assembly to cool it. Notation  55  shows the hub passageway where exhaust gasses leave the pistons. Notation  56  shows the passageway where exhaust gasses leave the hub assembly to enter the exhaust manifold. Notation  57  shows the fuel-air passageway through the hub where it would then enter into the cylinders.  
         [0025]      FIG. 9  shows the other side of the hub and cam assembly. Item  59  is one of the main bolts connecting to the cam assembly (same as item  49 ). It is solidly bolted to the hub assembly. The other smaller bolts similar to item  58  are bolted directly to the cam halves but mount in grooves in the hub assembly. They move to allow the articulation of the cam while still transferring engine torque to the hub assembly.  
         [0026]      FIG. 10  is a view from the front of the engine.  
         [0027]      FIG. 11  is a perpendicular cross sectional view of  FIG. 10  through broken line B and parallel to the axis of rotation. Notation  60  shows one of the coolant passageways through the block. These coolant passageways are arranged in a polygon to provide even cooling of the block and connect to the crossing passageways as depicted by notation  22 . Connected, these passageways are fed by one entry and one exit point to the engine at notation  30 .  
         [0028]     To match various applications, the engine of the type of the present invention may be made with multiple rings with any number of radially aligned pistons therefore providing for an unlimited number of pistons and configurations.  
         [0029]     Several embodiments of the present invention have been described in detail; however, various modifications may be made without departing from the scope and spirit of the invention. Accordingly the present invention is not to be limited, and is based upon the following claims.