Abstract:
A balanced rotary cycling machine suitable for use as an internal combustion engine, compressed gas or steam engine, compressor or pump is disclosed herein. The rotor assembly consists of four articulating pistons where the opposite pistons are inter-linked with each other by pivoted rods comprising a parallelogram mechanism and therefore eliminating a need for pivots between pistons. The rotor assembly rotates inside or outside of a circular or non-circular stator depending on the configuration chosen. A variety of mechanisms for shape deformation of four piston assembly during its rotating cycle is also disclosed herein, as well as detailed descriptions of preferred embodiments, including a four cycle internal combustion engine with circular stator, marine engine with polymer parts and a four cycle automobile rotary engine with conventional oil pan. In addition, a method of operation of external rotary combustion engine, employing a high-pressure compressor and an external combustion chamber, is disclosed. This invention also teaches a novel lubrication system for rotary engine providing low emissions. The engine has few moving parts, simplified circular or semi-circular stator shape and utilizes simple and effective sealing techniques. It is fully balanced, has very low friction and heat losses and can employ a pre-designed configuration of the combustion chamber for a desired compression ratio and power output.

Description:
[0001]     This application is a divisional of U.S. patent application Ser. No. 10/834,984, filed Apr. 30, 2004, which is a continuation in part application of U.S. patent application Ser. No. 10/160,072, filed Jun. 4, 2002, which claims priority from U.S. Provisional Application No. 60/295,577, filed Jun. 5, 2001. 
     
    
     FIELD OF THE INVENTION  
     Background of the Invention  
       [0002]     Variable shape rotors are known from the prior art, as an example of which was provided by Werner in (U.S. Pat. No. 716,970.). Another type of engine was disclosed by Wankel, who established a rotary engine with a fixed shape rotor and epitrochoidal shape stator.  
         [0003]     In present invention, during the rotation cycle, the rotor pivoting blades or pistons align alternatively in a lozenge and a square configuration so that the volume between the blades itself, side walls and the stator (contour wall) changes, and in so doing, allows to create a cycling machine.  
         [0004]     Rotary engines and cycling machines based on the principle set forth in Edward H. Werner&#39;s invention of 1902 (U.S. Pat. No. 716,970) and further inventions developed in greater detail.  
         [0005]     German Patent No. 1,295,569, provided a rotary internal combustion engine, in which two pistons are provided, which are connected to the shaft by means of two diametrically opposite arms fixedly connected to the shaft.  
         [0006]     A contemporary embodiment of the cycling machine utilizing Werner&#39;s principle is described in U.S. Pat. No. 6,164,263, in which roller carriages pivotally connected to the ends of the blades create a lateral support for the rotor and simultaneously provide a cam surface for the rotor shape deformation. In this device, an additional variation of the volume between the blades, side covers and a stator, is achievable due to variation in relative positions of the carriages and blades.  
         [0007]     Similar configurations are well known from prior art including U.S. patents by Jordan, Ishida and Niemland. These devices however, do not employ rollers at the end of sealing carriages, save for U.S. Pat. No. 3,387,596, by Niemand where rollers are used in combination with a cam surface for deformation of the shape of a four blade parallelogram.  
         [0008]     Parallelogram mechanisms for creating reciprocating movement of the pistons are known from U.S. Pat. No. 5,203,295, issued to Alexander. Multiple applications of unique properties of the parallelogram mechanism are also known, for instance from PCT WO 09105990 by Okulov.  
         [0009]     These arrangements are useful, however a common disadvantage exists in that the pivoting blades or links arranged in such configurations are extremely difficult to seal at the pivoting ends.  
         [0010]     In respect of the sealing difficulties, different sealing techniques and methods have been described in U.S. Pat. Nos. 3,950,117; 3,690,791; 3,918,415; 4,296,936, etc. Several different types of seals are needed to provide adequate sealing of the device similar to U.S. Pat. No. 6,164,263, which greatly complicates the design and compromises reliability. In addition, the complicated shape of the parts and greater surface area of the combustion chamber both determine high thermal losses and lower efficiency for this type of engine. Eliminating roller carriages in order to create a simpler shape for the combustion chamber (or considering its size near zero) results in the devices similar to those described in a U.S. Pat. No. 3,918,415.  
         [0011]     The geometry and numerous configurations of the rotor and stator shapes have been detailed in U.S. Pat. Nos. 3,950,117 and 5,288,217 for different types of variable shape rotors. The shape employed in U.S. Pat. No. 6,164,263 is generally described in the prior art and includes a non deformable rotor having one to four pivoted carriages running in a stator of square or other polygon like shape with rounded corners.  
         [0012]     Another variant of a reciprocating cycling machine by Huttlin (as an example see U.S. Pat. No. 6,009,847) employs four two arm levers with the ends of the arms rolling or meshing with each other through gear coupling. The assembly of levers rotates in a circular housing. The disadvantage of the configuration is that the combustion chamber has a very high surface to volume ratio, which leads to thermal inefficiency. Also, the unbalanced lateral forces applied against the cylindrical stator create friction losses and excessive wear of apex seals ( FIG. 10 ) followed by widening of the tolerance gap between levers. This compromises the performance of the already complicated sealing system, reduces the torque and increases complexity of the design.  
         [0013]     All these engines have an advantage of being near vibration free contrary to the Wankel and other type of engines with fixed shape rotor or unbalanced pistons. Disadvantages of such engines however exist in that seals at the pivoting ends of the blades or arm levers are complicated. There are still high friction losses due to the significant stress produced by gas pressure and complexity of the shape of the seals and joints.  
         [0014]     In addition, the rollers of the carriages are exposed to high temperature combustion gases and suffer from deposition of residue products or plaque from the combustion process. This very complicated configuration of the combustion chamber creates excessive heat transfer to its parts due to large surface area predetermined by the geometry of the pistons (blades). Due to the higher surface area of the combustion chamber/s relative to its volume/s, there are more residues from the non burnt film of the fuel. As in most rotary engines, due to centrifugal action of the rotating rotor forcing the lubricator oil to enter the exhaust, a tendency to have higher overall engine emissions still exists.  
         [0015]     There are also well known devices (so-called “cat and mouse” or scissors type engines) realized in a variety of configurations and utilizing principle of creating cycling volumes between rotating inside the circular or toroidal housing pistons or blades. The disadvantage of these engines is the need for creating an external mechanism for variation of the relative position of the pistons. These devices include cams, oval gears, rotating links mechanisms (Rice), etc. Other known types of balanced rotary engines are devices employing cylinders and pistons arranged in a circle and having an activating piston movement cam with a rotating shaft.  
         [0016]     Other engines are represented by concepts proposed in the prior art and include a pressure energy converter, rotary engine or compressor as in U.S. Pat. Nos. 4,068,985, 3,996,899; a rotary disk engine as in the U.S. Pat. No. 5,404,850; a rotary planetary motion engine as in U.S. Pat. No. 5,399,078; a rotary detonation engine as in the U.S. Pat. No. 4,741,154; a rotary combustion engine as in DE Pat. No. 2,448,828, U.S. Pat. Nos. 3,933,131, 4,548,171, 5,036,809; the Wankel type engine as in the U.S. Pat. Nos. 3,228,183, 4,308,002, 5,305,721, and a continuous combustion engine as in the U.S. Pat. No. 3,996,899. Most rotary engines, and particularly the Wankel and those described in the U.S. Pat. Nos. 3,442,257, 3,614,277, 4,144,866, 4,434,757, DE Pat. No. 3,027,208 are based on the principle of volume variation between a curve and a moving cord of fixed length as a single sliding piston and have the common disadvantage of being unbalanced.  
       SUMMARY OF THE INVENTION  
       [0017]     One aspect of one embodiment of the present invention is to provide an improved rotary internal combustion engine.  
         [0018]     The present invention provides an engine or fully balanced cycling volume machine with a variable shape rotor and low internal friction. The engine operates with reduced centrifugal forces on the oil or lubricant distribution and utilizes a conventional oil pan (pool) design solution which proved to be superior to other types of lubrication systems, particularly the ones used in conventional automobile engines.  
         [0019]     A further aspect of one embodiment of the present invention is to provide a rotary cycling machine for producing mechanical energy from pressurized fluid as well as to pump, vacuum and compress fluids, comprising: 
        a hollow housing having an internal contour wall and having side covers parallel to each other and perpendicular to a central axis of the housing;     ports in communication with the interior of the housing for intake, exhaust, lubrication or cooling;     a piston assembly having pistons in spaced relation and mounted for rotational movement within the housing;     deformation means independent of the contour wall for deforming said piston assembly;     linkage means connected to opposed pistons for permitting relative movement of oppositely linked pistons, the linkage means being connected to the deformation means; and     sealing means between pistons of the piston assembly for providing a continuous seal between all pistons of the assembly during rotation.        
 
         [0026]     The housing may comprise a stator and may optionally include a flexible liner which can cooperate with the sealing means to provide a very efficient and well sealed system.  
         [0027]     In terms of the piston arrangement, the assembly may comprise a minimum of two pistons depending upon the use of the cycling machine or up to four pistons arranged in a radial disposition and in sealing engagement with one another.  
         [0028]     Depending upon the number of pistons, this will obviously vary the linkage means as well. The linkages may comprise a pair of linkage arms or a complete array where a group of arms are arranged for movement subscribing to a parallelogram configuration.  
         [0029]     Still, another object of the present invention is to create an effective and simplified engine sealing system.  
         [0030]     It is another object to create the possibility of using a simple circular shaped stator and an efficient combustion chamber.  
         [0031]     Conveniently, the system of the invention provides for direct and linear transmission of mechanical torque from all four pistons to the shaft.  
         [0032]     As an advantage, engine components such as cams, rollers and pivoting parts can be isolated from exposure to combustion gases, while the weight of the engine is reduced and provides for cleaner exhaust.  
         [0033]     In view of efficiency of the design, the result is a lower rpm, more efficient engine, utilizing more efficient and less NOx.  
         [0034]     The engine provides for lower dead time and is tolerant to different fuels and suitable for photo-detonation mode as well as hydrogen combustion.  
         [0035]     Alternatively, another objective is to create an ignition device amplifying the internal pressure during the compression cycle to the point of ignition of air-fuel mixture and to provide an external combustion engine utilizing the compressor and expansion machines as per present invention. In this manner, the present invention provides for a rotary cycling machine for producing mechanical energy from pressurized fluid as well as to pump, vacuum and compress fluids, comprising: 
        a pair of rotary machines where the machines comprise: 
            a hollow housing having an internal contour wall and having side covers parallel to each other and perpendicular to a central axis of the housing;     ports in communication with the interior of the housing for intake, exhaust, lubrication or cooling;     a piston assembly having pistons in spaced relation and mounted for rotational movement within the housing;     deformation means independent of the contour wall for deforming said piston assembly;     linkage means connected to opposed pistons for permitting relative movement of oppositely linked pistons, the linkage means being connected to the deformation means; and     sealing means between pistons of the piston assembly for providing a continuous seal between all pistons of the assembly during rotation;    
            a first machine of the machines for compressing a fuel;     a combustion vessel for combusting compressed fuel from the first machine;     a second machine of the machines for receiving energy from combustion; and     a mechanical link between the first machine and the second machine.        
 
         [0047]     The rotor in accordance with one embodiment of the present invention comprises an assembly of four pistons or blades suitable for creating variable volumes during a rotation cycle and having sealed gaps between adjacent pistons and an oval or circular shape stator. Oppositely disposed pistons are pivotally linked to each other creating a parallelogram mechanism and where the intersections of the links are connected to the rotor shape deforming mechanism and are also coupled with the output shaft.  
         [0048]     The pistons can have individual seals with the stator and side covers creating variable volume chambers. Alternatively, the pistons may have seals between them, preferably at the centers of their relative rotation. Intake ports, spark plug and exhaust ports are provided either radially in the stator housing, or axially in the side covers, or both of these.  
         [0049]     Different sealing techniques are further presented where sealing between pistons and side walls of the stator generally constitute simple linear or curved semicircular spring loaded seals similar to the Wankel type engine seals. Apex seals are arranged either between the pistons and stator contour circular or oval wall or comprise additional seals supported in the mid angle between adjacent pistons and having apex seals with them. Other types of continuous seals when used are also disclosed.  
         [0050]     Advantageously, rotation of the rotor provides the pistons rotor to generate cycling volumes thus enabling compression, expansion or vacuum. The engine with four pivoting pistons would have four strokes cycle firing four times per every revolution, practically without dead time.  
         [0051]     In a further embodiment of the present invention, there is provided a rotary cycling machine for producing mechanical energy from pressurized fluid as well as to pump, vacuum and compress fluids, comprising: 
        a hollow housing having an internal contour wall and side covers parallel to each other and perpendicular to a central axis of the housing;     ports in communication with the interior of the housing for intake, exhaust, lubrication or cooling;     a flexible piston assembly mounted for rotational movement within the housing;     deformation means independent of the contour wall for deforming the piston assembly; and     continuous sealing means between pistons of the piston assembly for providing a continuous seal between all pistons of the assembly during rotation.        
 
         [0057]     As a particular advantage to the present invention, the flexible piston assembly may be one piece and thus can be extruded, molded or etched or formed by any other suitable manufacturing process. The use of the flexible piston assembly will have a particular value in certain engine types such as small engines used in garden tools, etc.  
         [0058]     The design of the engine also provides for an engine configuration capable of creating a jet propulsory system and creating an engine for water crafts employing polymer plastic or composite parts cooled directly in the water.  
         [0059]     In accordance with a further object of one embodiment of the present there is provided a rotary cycling machine for producing mechanical energy from pressurized fluid as well as to pump, vacuum and compress fluids, comprising: 
        a hollow housing having a stator wall and having side covers parallel to each other and perpendicular to a central axis of the housing;     ports in communication with the interior of the housing for intake, exhaust, lubrication or cooling;     a piston assembly surrounding the stator wall;     deformation means independent of the stator wall for deforming the piston assembly;     linkage means connected to opposed pistons for permitting relative movement of oppositely linked pistons, the linkage means being connected to the deformation means; and     sealing means between pistons of the piston assembly for providing a continuous seal between each piston and the stator of the assembly.        
 
         [0066]     The engine described above is particularly useful in the marine applications since the blades or propulsors of different varieties can be directly mounted onto the pistons which orbit the stator.  
         [0067]     In terms of the ports for exhaust dispersion and intake, the exhaust port may be positioned so that the exhaust is discharged directly into a water stream in the event that the engine is used as a marine engine with an intake in a position suitable for fuel intake, air intake, etc.  
         [0068]     In accordance with a further object of one embodiment of the present invention there is provided a linkage mechanism for linking piston members in a rotary engine, said engine having a stator and piston members, comprising: 
        first linkage arms having spaced apart ends;     second linkage arms having spaced apart ends arranged in a parallel plane relative to the first linkage arms;     connection means at each end of the spaced apart ends of the arms for movably connecting opposed pairings of the piston members;     roller means connected to arms of the first arms and the second arms for facilitating movement between connected arms of the first arms and the second arms; and     cam means about which the rollers orbit for movement of the piston members.        
 
         [0074]     The arrangement is particularly effective for advancement of the pistons and, as discussed herein previously, the movement of the linkage arms essentially moves from a substantially square arrangement to a rhomboidal arrangement and is conveniently positioned between the space defined by the pistons.  
         [0075]     By making use of a pair or several groupings of the cycling machines, an efficient energy producing apparatus can be formulated for a variety of different uses.  
         [0076]     Having thus generally described the invention, reference will now be made to the accompanying drawings, illustrating preferred embodiments. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0077]      FIG. 1  illustrates four segmental articulating pistons arranged in a lozenge configuration;  
         [0078]      FIG. 2  illustrates the pistons arranged in a square configuration;  
         [0079]      FIGS. 3 through 8  illustrate cycles of the engine operation;  
         [0080]      FIGS. 9 and 10  illustrate the prior art arrangements;  
         [0081]      FIG. 11  is a plan view of the preferred embodiment with part of the side cover and links not shown;  
         [0082]      FIG. 12  is a sectional view of the engine along line  12 - 12  of  FIG. 11 ;  
         [0083]      FIGS. 13 through 14 B illustrate methods of deformation of pistons assembly utilizing non-circular gears and/or rollers;  
         [0084]      FIGS. 15 through 18  illustrate variants of stator and rotor possible arrangements;  
         [0085]      FIG. 19  is an enlarged view of the described piston bed surrounding the contour wall with side covers;  
         [0086]      FIGS. 20 through 22  illustrate the sealing system according to one preferred embodiment;  
         [0087]      FIG. 23  is a representation of the geometry of the outer portion of a segmental piston (providing for a minimum volume between the piston and contour wall);  
         [0088]      FIG. 24  illustrates a variant of the rotor assembly with flexural pivots between pistons and flexural apex seals;  
         [0089]      FIGS. 25 through 25 D illustrate the machine and a lubrication system therefor;  
         [0090]      FIG. 26  is a perspective view of a seal element;  
         [0091]      FIG. 27  is a perspective view of a seal for use in the machine;  
         [0092]      FIG. 28  is a longitudinal cross-section of  FIG. 27 ;  
         [0093]      FIG. 29  is a perspective view of the spring for use in the seal of  FIGS. 27 and 28 ;  
         [0094]      FIG. 30  is a view of the seal in one embodiment;  
         [0095]      FIG. 31  is a view of the seal in another embodiment;  
         [0096]      FIG. 32  is a schematic representation of the seal of  FIGS. 30 and 31 ;  
         [0097]      FIG. 33  is a representation of the geometry of one quadrant of the engine circular contour wall and with possible positions of one of the segmental pistons;  
         [0098]      FIG. 34  illustrates the geometry of the circular stator (contour wall) and half circle shape of segmental pistons;  
         [0099]      FIG. 35  is a representation of the geometry of the cycling machine with a non-circular shape, symmetrical contour wall or cam surface;  
         [0100]      FIG. 36  illustrates variations of possible shapes of a symmetrical non-circular contour wall or cam surface;  
         [0101]      FIGS. 37 through 38 A illustrate the method of mathematical definition of the contour wall or cam geometry, particularly with non-symmetrical configuration described in a  FIG. 38A ;  
         [0102]      FIG. 39  is a variant of the engine with combustion chambers defined by a contour wall and pistons surrounding it;  
         [0103]      FIG. 40  is an elevational view of the engine of  FIG. 39  schematically illustrating the lubrication system and oil pan;  
         [0104]      FIG. 41  is another view similar to  FIG. 13  showing the piston assembly in lozenge configuration;  
         [0105]      FIG. 42  illustrates an engine configuration with pistons coupled directly with fins and surrounding a non-circular stator;  
         [0106]      FIG. 43  illustrates an amplified compression type ignition plug;  
         [0107]      FIG. 44  illustrates a graphical representation of the method of amplification of pressure inside the ignition chamber of the plug of  FIG. 43 ; and  
         [0108]      FIGS. 45 and 46  illustrate the principle of an external combustion engine according to the present invention; 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0109]      FIG. 1  illustrates a cross-sectional view of the rotary apparatus, generally denoted by numeral  10 .  FIGS. 11 and 12  illustrate a side and partially cutaway view of the arrangement  10 , respectively. With respect to  FIGS. 1, 11  and  12 , the arrangement  10  provides a housing  12  having end covers  14  within which is disposed a stator  16 . The stator is shown in the example as a circular arrangement; however, the arrangement may also be of a semi-circular shape or have an adjustable liner to be discussed hereinafter.  
         [0110]     Disposed within the housing  12  is a plurality of pistons  18 , shown in the example in a quantity of four. As is illustrated, the pistons  18  have a general arc shape for contact with the stator  16 . The internal area of the pistons includes a plurality of generally rounded or scalloped portions  20 . The scalloped portions are configured to permit general movement of linkages  22 .  
         [0111]     As illustrated, diametrically opposed pairings of pistons  18  are connected by linkages  22 . Each of the linkages  22  includes at either end connecting axles  24 . In this manner, each of the linkages allows for movement of the piston  18  relative to the linkage  22 , the movement being accommodated by the piston scalloped sections  20 .  
         [0112]     As illustrated in  FIG. 1 , the linkage arms  22  for an opposed pairings of pistons  18  overlie the linkage arms  22  of the opposing pairing of pistons. In order to connect the opposed individual pairings of pistons  18 , the overlying linkage arms  22  are connected together for relative movement. This is achieved by axles of rollers  26  which connect alternating individual linkage arms of one layer with similar arms from the second layer. Accordingly, the linkage arms  22  are effectively arranged in an array with the rollers  26  connecting alternating arms of the first array or top layer with the similar arms from the second array or underlying group of linkage arms  22 . This effectively connects the linkage arms  22  of opposed pairings of pistons  18  with the second opposed pairing. As is illustrated in  FIG. 1 , rollers  26  are positioned at the point of intersection, between connected first layer and second layer linkage arms  22 .  
         [0113]     Extending through housing  12  and covers  14  there is provided a central shaft  28  having a generally cross-shaped coupling member  30 , which member  30  includes slots for engagement with the axes of rollers  26 . This is best illustrated in  FIG. 11 . A central shaft support  32  is coaxially arranged about central shaft  28  and includes radial and thrust bearings  34 .  
         [0114]     Generally speaking, the shape of the rotor assembly changes from the lozenge shape of  FIG. 1  to the square configuration as illustrated in  FIG. 2  under influence of a piston deformation assembly. As illustrated in  FIG. 1 , the arrangement of the rollers  26  effectively changes from a rhomboidal configuration to a substantially square configuration under the action of the deformation mechanism. As an example, the deformation mechanism can comprise a cam member or members  36 . In the example, the shape of the cam  36  is generally ovular and symmetrical, however it will be understood that the underlying concept with respect to the shape is that the same must include at least one minimum and one maximum curvature. In this regard, although illustrated in ovular shape, by consideration of the minimum maximum curvature other shapes are clearly within the realm of possibility including prolated circular structures. The cam arrangement  36  may be an integral part of the shaft support  32  or, in the alternative, the deformation mechanism can include non-circular gear arrangements or pivoting members or others. An example of the alternative is illustrated in  FIGS. 13 through 14 B. In this arrangement, the deformation arrangement may include non-circular gear members  38  together with central static gear  40  comprised of cylindrical member  42  having teeth  44 .  
         [0115]     In use, and returning to the arrangement in  FIGS. 1, 11  and  12  by virtue of the rollers  26  and the disposition of the axes being at intersections of the links  22 , the deformation system allows rocking of the system against the cam arrangement.  
         [0116]     As briefly mentioned herein previously,  FIG. 2  illustrates the configuration of the linkage arms  22  in the generally square configuration with respect to rollers  26 .  
         [0117]     In  FIGS. 3 through 8 , the overall operation of the arrangement is shown, however, it is to be noted that in this embodiment only four linkage arms  22  are shown. The ports for intake and exhaust are denoted by numeral  46   a  and an example of a spark plug is denoted by numeral  26   a . As pointed out previously, the arrangement of the linkage arms  22  and specifically the disposition of the rollers  26  relative to one another, alternatively changes from a rhomboidal configuration to a square configuration.  
         [0118]     It will be appreciated by those skilled in the art that by a simple variation of the number of intake ports and exhaust ports, the arrangement shown in FIGS.  3  though  8  can be modified so that the engine can operate as a two-cycle or two-stroke engine. As a further alternative, the inner-cycling volume of the engine, i.e. volume between the pistons, or an external blower may also be utilized.  
         [0119]     One of the primary advantages of the engine set forth herein is realized by the fact that the deformation mechanism is not part of the stator, rotor or contour wall. This easily permits adjustment of the properties to burn different fuels, create different compression ratios, modify the relationship between the combustion/intake/expansion chambers volume and angles of the rotor assembly rotation. Clearly, this translates into an arrangement where horsepower can be augmented with relative ease without having to extensively reconstruct the arrangement or simply discard the housing rotor, etc. This has significant advantages and has not been previously proposed in the art view of the limitations in the structures of the prior art.  
         [0120]     In greater detail with respect to the pistons  18 , the same may include a hollow volume  46  as illustrated in  FIG. 12 , the purpose for which will be discussed hereinafter. The number of pistons  18  will vary from one application to another with a minimum of two pistons. A “chain-like structure” can be achieved with multiple chambers or a “wavy” disc coupled with a single or multiple tiltable chambers. This configuration may effectively be used in pumps, pneumatic breaks for vehicles (a pump with a closed output and a “wavy” disc like stator), propulsors for a watercrafts, etc. A variety of possible arrangements of pistons  18  and stators  12  are shown in  FIGS. 15 through 18  where chambers  48  are created between them.  
         [0121]     In respect of the sealing system of pistons surrounding the contour wall and which may be incorporated into the present invention, pistons  18  as illustrated in  FIG. 19  as an example, may include lateral seals  50 , generally disposed along the inside wall of the side covers  14  with additional seals  52  for contact with the contour wall or “wavy disk stator/rotor” (not shown).  
         [0122]      FIG. 20  illustrates additional sealing arrangements where the individual pistons include apex seals  54 , lateral seals  50  and inter-piston seals  58 .  FIG. 21  illustrates an enlarged section of the apex and lateral seal system.  FIG. 22  illustrates preferred configuration for the sealing where a spring  60  loads the apex seal  54  and apex seal  62 . This arrangement is similar to the Wankel-type engine seals, however, the advantage with this arrangement is that there is a much more favourable leaning angle associated with the apex seals. This is found to be best when the leaning angle is not greater than 10 degrees compared to between 16 and 30 degrees for Wankel-type engines. In respect of the leaning angle, reference can be made to  FIG. 23 . The inter-piston seals  58  can be arranged in the form of flexible members.  
         [0123]     As a further variation, continuous seals may also be employed in combination with a toroidal stator or toroidal shape rotor pistons. The seals are as effective as conventional piston engine seals. One of the beneficial features of the arrangement is that the rotor assembly and seals, shown in  FIG. 24  and represented by numeral  62 , can be a one-piece molded, extruded or etched part with pistons  18 , inter-piston flexural links  64  with spring loaded flexible apex seals with the spring being noted by numeral  66  and apex seal  68 .  
         [0124]     Turning now to  FIGS. 25 and 26  through  32 , shown is a further variation on the sealing arrangement according to the present invention. As a particularly attractive arrangement, the inter-piston seals according to the embodiment shown in  FIG. 25  and generally denoted by numeral  70  may comprise a generally cylindrical structure which may include a plurality of sections  72  and  74  where the sections are moveable relative to one another. The cylindrical sealing element  70  may be tubular and include a sealing insert  76  disposed coaxially therein. The sealing insert  76  also may include a longitudinal bore  78  within which is disposed a torsional spring  80 . The spring  80  and insert  76  are disposed within the cylindrical sealing element such that the end portions of the spring are turned downwardly and extend through the insert as illustrated in  FIG. 28 . The sealing member may be isolated into the sections  72  and  74  by a zigzag cut or by a helical cut as illustrated in  FIG. 27 .  
         [0125]     The spring  80  is a torsional spring and would facilitate rotation in opposed directions of the individual segments  74  and  76  which in turn will facilitate axial movement of said segments. This is best illustrated in  FIG. 32  where the arrangement is shown where the sections  72  and  74  are connected and secondly where the sections have slightly pulled apart from one another, thus introducing a gap  82  between the sections  72  and  74 . By providing the tortional spring, the seal can provide both axial, i.e. in the direction of the central shaft sealing, as well as radial sealing. In this manner, the seal is effectively a “dynamic” seal and adjusts by movement of the body itself relative to stresses experienced during rotation of the pistons. In the radial direction it acts similar to a ball-type valve where external pressure only facilitates its sealing capability.  
         [0126]     Materials for construction of the seals discussed herein will be selected from the materials well-known to those skilled in the art for sealing environments where significant stresses and wear conditions are encountered as well as high heat and thermal expansion of the seals.  
         [0127]     Returning now to a discussion on the pistons, the height of each piston may be approximately equal to half of its length. See as illustrated in  FIGS. 33 and 34 . This provides a minimum variation in the clearance between the top of the piston and the contour of the stator circular wall as graphically illustrated in  FIG. 23 . As an example, with a stator inner-diameter of 100 millimeters (4 inches) the length of the piston may be 54 millimeters (2.13 inches) with the height comprising 23 millimeters (0.9 inches). The variation in the gap between the apex of the piston found at apex seal  54  ( FIGS. 20 and 21 ) will be in the range of between 0 and 0.3 millimeters (0-0.012 inches). This minor variation be can easily accommodated by movement in the seating of the seal. Alternatively, this variation can be canceled by providing a slightly non-circularly shaped stator by either machining or deforming a flexural stator or liner. This is generally illustrated in  FIGS. 38 and 38 A.  
         [0128]     The “ideal geometrical configuration” (as established in  FIGS. 33 and 34 ) involves piston segments of equal to or less than twice the radius of the stator contour wall. Sealing in this configuration in high RMP devices can employ the “close to zero” gap technique where, depending on the density of the working fluid, very sufficient pressures can be achieved without seals at all, but with minimum clearance between the parts. This particular configuration would be preferable with ceramic, composite or plastic parts employed which may be especially advantageous for lubricant-free engines as well as in micro-engines etched from silicon-based materials.  
         [0129]     The geometry of other variations and details of engines and cycling volume machines is set forth in Figures provided herein. The variation shapes of the “oval” stator or geometry of the cam surfaces ( FIGS. 35 and 36 ) as well as their semi-symmetrical types ( FIG. 38A ) and other parameters are numerous and may be analyzed using mathematical analysis techniques.  
         [0130]     The geometry chosen will determine the compression ratio and displacement of the engine. The shape of the curve must conform with two points, namely points  1  and  2  in  FIG. 35  or  FIG. 38A . The distance between the points must equal the side of the C 2  and a polar angle between them must be equal to 90 degrees. Such a curve has an infinite amount of geometrical solutions predetermined by the ratio A/B and by at least one fragment of the curve between points  4  or  6  and  5  which are reference points for all possible curves with a similar ratio of A/B. Point  5  is a common reference point for all possible symmetrical curves.  FIGS. 37 through 38 A illustrate the method of mathematical definition of the contour wall.  
         [0131]     As a particularly favourable feature of the present invention, the compression ratio of the instant engine is not limited by its geometry, which is contrary to the Wankel-type engine where the compression ratio cannot exceed 15.5:1 for a three-lobe rotor. The displacement of engines made in accordance with the present invention is to be compared to a four-cylinder, four-cycle engine since it will have an equal number of power strokes per one revolution of the shaft. As an example, the circular stator shape engine of the present invention with the displacement of 2.7 liters will have a contour wall diameter of approximately 12 inches and a thickness of 3.3 inches.  
         [0132]     In a preferred embodiment, central shaft  28 , as indicated previously has a cross-leg shape coupling member  86  with slots  88  where engaging the axes of the linkage arms  22 . As an alternative, the torque and lateral forces resulting from the pressure within the housing  12  can be transferred through the pistons depending on the configuration chosen.  
         [0133]     Referring now to  FIGS. 39, 40 ,  19  and  41 , the engine with a non-circular or oval-shaped stator  16  may be provided with different types of chamber arrangements. In one possible embodiment, as illustrated in  FIG. 39  there is included the housing  12  having the pistons surrounding the stator ring from the inner or outer portion of the stator ring to create a corresponding number of chambers  90 . In the situation where the pistons are positioned inwardly, the possibility exists to employ a conventional oil pan  92  ( FIG. 40 ) for lubrication which simplifies the design, improves reliability and provides for low emissions.  
         [0134]     The lubrication can include a filter  94 , oil radiator  96  and pump  98 . The distribution can be effected through central shaft  28  having passages  100  there through. The distribution can be assisted by centrifugal forces which will facilitate circulation.  
         [0135]     Returning to  FIGS. 25 through 25 D, shown are greater details concerning a lubrication system according to further embodiments of the present invention. In respect of  FIG. 25 , as discussed with respect to  FIG. 40 , the central shaft includes passageways  100  within which the oil may be dispersed. In the embodiment of  FIGS. 25 and 25 B, the pistons  18  include within the hollow areas  46  lubricant or oil which can be recirculated through the system via the pistons and central shaft  28 . To this end, the pistons may include oil pumps, globally denoted by numeral  102  and illustrated in  FIG. 25A . As illustrated in  FIG. 25A , the overall oil pump mechanism is part of the extensions of the central shaft  28  and is immersed in the oil  46 . 1 . Within piston  18 , as discussed herein previously, there is a chamber within which the pump mechanism  102  operates. In greater detail,  FIGS. 25A, 25C  and  25 D illustrate the components of the pump mechanism. Generally speaking, within the body of the piston  18  there is a chamber  102 . 1  within which a moveable plunger  102 . 2  is slidable from the position shown in  FIG. 25C  to the position shown in  FIG. 25D . Plunger  102 . 2  is actuated by a spring member  102 . 3  disposed within or adjacent to the body of the plunger  102 . 2 . An O-ring member  102 . 4  facilitates sealing of the plunger  102 . 2  during its movement (extension and retraction) shown in  FIGS. 25D and 25C , respectively. A ball valve assembly, generally denoted by numeral  102 . 5  is positioned about the opening  102 . 1 . The assembly includes ball valves  102 . 6  and  102 . 7  which are retained by retaining member  102 . 8 . As is evident from  FIGS. 25C and 25D  the ball valves  102 . 6  and  102 . 7  and plunger  102 . 2  cooperate during articulation of the pistons  18  such that oil is either admitted as shown in  FIG. 25D  or discharged as shown  FIG. 25C  where the discharge of the oil is passed through channel  102 . 9  for eventual readmission into the channels  100  of central shaft  28 .  
         [0136]     Turning to possible alternatives for the instant technology, the engine may be incorporated by watercraft devices with the respective parts being composed of suitable polymeric materials, composites, etc. with the entire engine capable of being submerged in the water for effective cooling. This embodiment is generally illustrated in  FIG. 42 . In the embodiment, each piston can have a blade  106  schematically shown in  FIG. 42 , or other suitable water displacing structure directly attached to the piston. The configuration of pistons can include cover permitting desirable shape for controlling fluid dynamics.  
         [0137]     In respect of four stroke combustion engines, the four chambers may be used in a closed circuit with the cycles defined as follows: intake, compression, expansion and exhaust ( FIGS. 3 through 8 ). The intake ports may utilize conventional carburetor technology or can be fitted with a gas or diesel fuel injector (not shown). Alternatively, the fuel may be injected directly into the chamber. It is also envisioned that continuous combustion can be achieved by utilizing a flame pilot technique or providing a channel between the chambers. As a further alternative to a conventional spark plug  26   a  ( FIGS. 3 through 8 ), or a pair of such plugs custom to Wankel-type engines, a compression diesel igniter such as that shown in  FIG. 43  and represented by numeral  110 , may be used where the pressure of an air/fuel mixture is mechanically multiplied by a differential piston  112 ,  114  with the pressure and displacement being illustrated in  FIG. 44 . Upon reaching a certain displacement, a spring  116  of igniter  110  sliding within a liner  118  confines the chamber  1  to P 2    
         [0138]     The ignition timing may be achieved using electronic ignition or controlling the injection of fuel directly into the combustion chamber. The conventional spark plug cavity can be exposed to the inner volume of the chamber by means of porting the bi-rotation of the pistons.  
         [0139]     The engine as set forth herein advantageously does not require a flywheel as the inertial capability of the piston assembly is sufficient to provide smooth rotation even on low RPMs. The projected maximum RPM of the engine is between about 3000 and 5000 RPM due to the quadruple firings per revolution which, in many instances, requires a significantly less complicated gear box or no gear box whatsoever.  
         [0140]     In terms of cooling, the engine may be cooled by air, water or oil or in any traditional fashion for rotary engines. Where an oil pan is employed, the intensive circulation with the oil together with an external heat exchanger and filter, as discussed herein previously, may be used. More over, as a single rotor engine can be easily scaled up for achieving of quite a sufficient power rating, a direct air cooling system can preferably be employed allowing cooling of the engine housing uniformly from all sides. In addition, the asymmetrical pattern of heating predetermined by fixed position of combustion chamber can be easily smoothen by integration of an oil cooling exchanger into a coldest part of the stator itself, therefore reducing thermal stresses to the engine parts.  
         [0141]     The engine in accordance with the present invention may be used as an expansion type machine compatible with numerous types of fluids such as steam, compressed or liquefied gasses, hydrogen, etc.  
         [0142]     As a further alternative, as illustrated in  FIGS. 45 and 46 , two cycling machines may be arranged in a way that one machine  124  compresses an oxidizer such as air, and delivers it along with fuel into a high pressure combustion chamber  126  having a thermal insulation liner  128 , where the energy of the products of continuous and easily optimized combustion will be fed into the expansion machine  130  through a thermally-insulated passage  132 . Part of the energy created may be returned to the compressor  124  by a mechanical or electro-mechanical link  134 .  
         [0143]      FIG. 45  or  46  further illustrate a similar configuration of the external engine employing a hybrid system where the compressor  124  is driven by an electric motor or where the expansion machine is assisted by electric motor (not shown) as well as a machine where the exhaust will be fed back to the outer part of the combustion chamber  128  with an additional shell  136 .  
         [0144]     The arrangements as set forth herein greatly overcome the limitations of the prior art and in particular provide for arrangements where thermal energy is conserved, in a view of a sophisticated sealing arrangement, and where the operating efficiency is significantly enhanced over which was previously proposed and further, an arrangement which is capable of burning a variety of different fuels and producing a variety of different compression ratios by simple replaceable piston assemblies and deformation assemblies associated with the pistons.  
         [0145]     Although embodiments of the invention have been described above, it is limited thereto and it will be apparent to those skilled in the art that numerous modifications form part of the present invention insofar as they do not depart from the spirit, nature and scope of the claimed and described invention.