Abstract:
A rotary engine including a static toroidal cavity having an inlet port for introducing fuel and air to the cavity and an outlet port for exhausting products of combustion from the cavity. A first power train including a first output shaft and a second power train including a second output shaft are located partially within the cavity and able to rotate in the first direction. A plurality of pistons are positioned around a perimeter of the toroidal cavity and between the first and second power trains. The plurality of pistons are movable with respect to the cavity and include a first set of pistons connected to rotate with the first power train and a second set of pistons connected to rotate with the second power train. The plurality of pistons defining a plurality of chambers therebetween. Combustion of a fuel air mixture within a first one of the plurality of chambers causes a fuel gas mixture to be introduced into a second one of said plurality of chambers through the intake port, combustion material to be exhausted from a third one of the plurality of chambers and one of the first and second drive trains to rotate in the first direction. A subsequent combustion of a fuel air mixture in one of the plurality of chambers causes the other of the first and second drive trains to rotate in the first direction, the first and second drive trains alternating movement upon subsequent combustions.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to internal-intermittent-combustion engines, and, more specifically, to a sequential rotary piston engine. 
     2. Description of the Prior Art 
     Heat engines are classified as the external-combustion type (the working fluid is entirely separated from the fuel-air mixture, and heat from the products of combustion are transferred through the walls of a containing vessel or boiler), and the internal-combustion type in which the working fluid consists of the products of combustion of the fuel-air mixture itself. Nowadays, the reciprocating internal-combustion engine and the steam turbine are by far the most used types of heat engines with the gas turbine in wide use only for high-speed aircraft. 
     Fundamental advantages of the reciprocating internal-combustion engine over power plants of other types are the absence of heat exchangers in the working fluid stream, the parts of the internal-combustion engine can work at temperatures well below the maximum cyclic temperature, a lower ratio of power-plant weight and bulk to maximum output (possibly except in the case of units of more than 10,000 hp), mechanical simplicity, and the cooling system handles a small quantity of heat. 
     The advantages of the reciprocating internal-combustion engine are of special importance in the field of land transportation, where small weight and bulk of the engine and fuel are always essential. In our present civilization the number of units and the total rated power of internal-combustion engines in use is far greater than that of all other prime movers combined. 
     The reciprocating internal-combustion engine dates back to 1876 when the German engine pioneer, Nikolaus Otto, developed the spark-ignition engine, and 1892 when Diesel invented the compression-ignition engine. Since then, engines have experienced a continuous development as our knowledge of the engine process has increased, as new technologies appeared and as the demand for new types of engines arose. 
     Usually, in a intermittent internal-combustion engine, a major moving part, called a piston, slides backwards and forwards in a straight line, inside a cylindrical cavity called cylinder. Such movement causes a volume variation of the cavity formed by the piston and the cylinder, that is used to perform a two or a four-stroke cycle. 
     An alternative to the design of linear-reciprocating-internal-combustion engine is the rotary design. The advantages of rotary over reciprocating action are primarily a matter of compactness, geometry, weight and cost of manufacturing. 
     Even before Otto&#39;s 119-year-old idea got its first positive results, some ideas like the Pump of Ramelli were developed. (Ramelli&#39;s Pump, developed in the sixteenth century, is the oldest reference to this type of rotary machines). Many engines of this category have been built, but the only one that has been developed to the point of quantity production is the Wankel (used in a line of sports-type cars by Mazda of Japan), where a rotating member is arranged to vary the working volume by an eccentric motion within a non-circular space. The most difficult problem with this engine is that of sealing the combustion chamber against leakage without excessive friction and wear. This problem is far more difficult than that with conventional piston rings as a “line of contact” instead of a surface of contact is usually involved and the surfaces to be sealed are discontinuous, with sharp corners. The Wankel engine is indeed smaller and lighter and has less vibration than conventional engines of the same output. There is no evidence that it is cheaper to produce. The sealing problem seems to have been solved as far as reasonable durability is concerned, but there is evidence of considerable leakage. This defect and the attenuated shape of the combustion chamber are responsible for poor fuel economy as compared with the equivalent conventional engine. 
     The idea of engines which toroidal pistons rotate or reciprocate within toroidal cylinders has also been advanced (like the Scott&#39;s Omega engine in the 1960&#39;s, where pistons reciprocate in a toroidal cylinder by means of a complex arrangement of cranks and shafts). The difficulties of connecting such pistons to the output shaft by a simple and reliable mechanism, together with the problem of sealing the sliding surfaces involved, caused the abandonment of such ideas. 
     Examples of such rotary engines are provided in the prior art. For example, U.S. Pat. Nos. 3,186,383; 3,937,187; 4,035,111 and 5,242,288 all are illustrative of such prior art. While these units may be suitable for the particular purpose to which they address, they would not be as suitable for the purposes of the present invention as heretofore described. Furthermore, whatever the merits, features and advantages of the above cited references, none of them achieve or fulfill the purposes of the Sequential Rotary Piston Engine (S.R.P.E.) of the present invention. 
     U. S. Patent No. 3,186,383 
     Inventor: Martin Cordingley Potter 
     Issued: Jun. 1, 1965 
     This invention concerns internal combustion engines and more particularly relates to rotary engines. This invention includes an output shaft, a body member mounted for rotation about the axis of the shaft, a plurality of annular cavities within the body member having a center of curvature on the rotational axis of the body member, an arcuate piston in each cavity, connector means secured to the pistons transmitting motion of the pistons to the output shaft, inlet means in the chambers whereby fuel may be applied to the combustion chambers between the pistons and end faces of the cavities, means for removing burnt gases from the chambers, first unidirectional clutch means between the body member and a fixed support, second unidirectional clutch means between the connector means and a fixed support, third unidirectional clutch means between the body member and the output shaft, fourth unidirectional clutch means between the connector means and the output shaft, the first and second unidirectional clutch means preventing motion of the body member and connector means relative to the fixed support in the reverse sense of the output shaft, the third and fourth clutch means allowing overrun of the output shaft relative to the body member or connector means. 
     U.S. Patent Number 3,937,187 
     Inventor: Henry Bergen 
     Issued: Feb. 10, 1976 
     A toroidal cylinder is provided with a slot formed around the inner wall. A central shaft carries a sun wheel engaging a set of planet gears which in turn engage a fixed ring gear secured to the cylinder adjacent the slot. A pair of rings are provided carrying sets of pistons running within the cylinder, the edges of the rings sealably running within the slot. Pins on the planet gears engage slotted arms secured to the rings so that opposite pairs of pistons move toward and away from one another in sequence thus providing compression and expansion strokes in the cylinder together with intake and exhaust strokes. A fuel mixture ignited by spark plugs or the like may be used or, alternatively, fuel injection may be utilized and inlet and exhaust ports are formed within the walls of the toroidal cylinder. 
     U.S. Patent Number 4,035,111 
     Inventor: Peter J. Cronen, Sr. 
     Issued: Jul. 12, 1977 
     A rotary engine having a toroidal chamber which is stationary, and in which the pistons convey power to a common crankshaft under the control of a four-bar linkage including novel means for preventing reverse motion of any piston in the chamber. Inlet and exhaust valves to control the flow of energizing fluid are provided, and are actuated directly from the crankshaft. Novel sub-components include the four-bar linkage, the valve mechanism, and the arrangement by which rotary movement of the pistons in the chamber is eliminated. 
     U.S. Patent Number 5,242,288 
     Inventor: Ogden W. Vincent 
     Issued: Sep. 7, 1993 
     An engine or pump is described which has a round cylinder in cross section, the surface of the cylinder being a round toroidal tube in the rotary direction. Fhe cylinder is made of two equal parts, one part fixed and one part rotating with each part meeting on a flat surface at a right angle to the drive shaft. Force exerted axially against the rotating cylinder where the two parts meet on the flat surface. The spring diaphragm is pre-loaded by a thrust bearing in a pre-loading disk to apply force to the rotating part of the cylinder. Within the cylinder are one or more round toroidal section pistons that are attached to the rotating part of the cylinder by piston pins. A hinged internal cylinder abutment is actuated by the piston as the piston passes through the abutment section. Working fluid to the cylinder is controlled by an internal valve actuated by a cam-disk on the drive shaft. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention relates generally to internal-intermittent-combustion engines, and, more specifically, to toroidal rotary engines. 
     A primary object of the present invention is to provide a toroidal rotary engine that will overcome the shortcomings of prior art devices. 
     Another object of the present invention is to provide a toroidal rotary engine which is smaller, lighter, more completely free of vibration, cheaper, and mechanically simpler than the reciprocating linear internal-combustion engine. 
     A further object of the present invention is to provide a toroidal rotary engine including a simple control mechanism, an acceptable sealing of the sliding surfaces involved, and a reliable and simple connection between the toroidal pistons and output shaft. 
     A yet further object of the present invention is to provide a toroidal rotary engine that allows the fitness of a two or a four-stroke cycle with a spark-ignition or a compression-ignition system. 
     Another object of the present invention is to provide a toroidal rotary engine that is simple and easy to use. 
     A still further object of the present invention is to provide a toroidal rotary engine that is economical in cost to manufacture. 
     The foregoing and other objects are achieved by placing an even number of toroidal pistons (of identical size) into a closed toroidal cavity. The entire toroidal cavity is divided into smaller cavities or chambers according to the chosen even number of toroidal pistons (the size of the pistons are designed to fit into the toroidal cavity in order to provide a sealing action of the resulting cavities in relationship with their adjacent ones), and the actual working volume of the engine is the volume of the whole toroidal cavity less the volume occupied by the chosen even number of toroidal pistons. The toroidal pistons are arranged in two identical groups. Each of the two identical groups comprises one half of the even number of toroidal pistons placed symmetrically around the 360° of the toroidal axis and connected to each other by a rigid connecting structure. The toroidal pistons belonging to one of the two identical groups are caused to move with solidarity as they are attached to the connecting rigid structure. This implies that when both groups are placed inside the toroidal cavity, the toroidal cavity is divided into an even number of smaller cavities or chambers equal to the chosen even number of toroidal pistons. Specific static areas of the entire static toroidal cavity are chosen to perform a specific action of the selected cycle of the engine (like the intake and the exhaust areas). If one of the two identical rigid symmetrical groups of toroidal pistons remains static by the action of a simple control mechanism in a specific place of the toroidal cavity, while the other one rotates inside the entire toroidal cavity (the movement caused by the pressure changes within the cavities or chambers of the engine due to burning the selected mixture of air and fuel), the toroidal cavities, formed by the placing of the two groups of toroidal pistons inside the entire toroidal cavity, experience a volume variation (half of the total even number of toroidal cavities will increase their volume and, obviously, the remaining cavities will diminish their volume). A relation of design is established between the maximum and minimum allowed volume for the toroidal cavities (it is also performed by the control mechanism). The motion of the free group starts when the relation of volumes is in the maximum for half of the toroidal cavities while, of course, in the minimum for the other half of toroidal cavities and, the position of the toroidal pistons and toroidal cavities matches with the position of the specific zones of the entire toroidal cavity in order to perform a cycle. 
     The moving group of toroidal pistons moves into the entire toroidal cavity until the toroidal cavities that were at the allowed maximum volume at the beginning of the motion diminish their volume to the established minimum. This implies that the toroidal cavities that were at the allowed minimum volume at the beginning of the motion, now are at the established maximum volume. After reaching this point, the control mechanism allows both groups of toroidal pistons to move together (which implies that there is no volume change in the toroidal cavities), performing a replacement action, (this means that all the toroidal pistons and all the toroidal cavities move in order to match with the static areas of the toroidal cavity to perform a new cycle). 
     Now, the group that was static in the previous cycle moves, while the group of toroidal pistons that was in motion in the previous cycle is static. The volume variations in the toroidal cavities are used to fix and perform a selected cycle (a two-stroke-cycle or a four-stroke-cycle). The groups of toroidal pistons describe a non-reciprocating sequential rotary motion. These two symmetrical groups of toroidal pistons are connected to two output shafts which movement is rectified by any known means in order to obtain a continuous non-sequential rotary motion. 
     The even number of toroidal pistons, the size of them, as well as the chosen cycle, depend on many design criteria, but the total number of toroidal pistons to be used is: 
     for two-stroke-cycle: 
     P=2n, where n=1,2,3,4 . . . 
     for four-stroke-cycle: 
     P=2 n , where n=2,3,4 . . . 
      where P is the even number of toroidal pistons (equal to the number of chambers) to be used by the S.R.P.E. 
     Due to the fact that in the four-stroke-cycle the number of different strokes is 4 (intake, compression, power and exhaust strokes) the number of cavities formed by placing the even number of toroidal pistons inside the entire toroid must be a multiple of 4, and for the two-stroke-cycle case, the even number of cavities to be used must be multiple of 2 (compression and power strokes). 
     The reasoning behind these formulas will become apparent from the following detailed description. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. 
     The features and advantages of the present invention will become apparent from the following detailed description of a preferred embodiment of the invention, when read in connection with the accompanying drawings. 
     The accompanying drawings, which are incorporated in and constitute part of the specification, illustrate one embodiment of the invention and together with the description, serve to explain the principles of the invention. 
     It should be noticed that the set of drawings includes all normal functions required in a complete internal combustion engine, this is, combustion chambers, pistons shafts to transmit the so created motion as well as a timing mechanism to coordinate it among the different parts of the machine. All starter, ignition and fueling systems can be accommodated by the common practices related herein. 
     Additional objects of the present invention will appear as the description proceeds. 
     A rotary engine including a static toroidal cavity having an inlet port for introducing fuel and air to the cavity and an outlet port for exhausting products of combustion from the cavity is disclosed by the present invention. A first power train including a first output shaft and a second power train including a second output shaft are located partially within the cavity and able to rotate in the first direction. A plurality of pistons are positioned around a perimeter of the toroidal cavity and between the first and second power trains. The plurality of pistons are movable with respect to the cavity and include a first set of pistons connected to rotate with the first power train and a second set of pistons connected to rotate with the second power train. The plurality of pistons defining a plurality of chambers therebetween. Combustion of a fuel air mixture within a first one of the plurality of chambers causes a fuel gas mixture to be introduced into a second one of said plurality of chambers through the intake port, combustion material to be exhausted from a third one of the plurality of chambers and one of the first and second drive trains to rotate in the first direction. A subsequent combustion of a fuel air mixture in one of the plurality of chambers causes the other of the first and second drive trains to rotate in the first direction, the first and second drive trains alternating movement upon subsequent combustions. 
     To the accomplishment of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated and described within the scope of the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     Various other objects, features and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views. 
     FIG. 1 is a front perspective view of the toroidal rotary engine of the present invention; 
     FIG. 2 is a cross-sectional view of the toroidal rotary engine of the present invention taken along the line  2 — 2  of FIG. 1, illustrating the toroidal cavity housing and one shaft contained within another; 
     FIG. 3 is a cross-sectional view of the toroidal rotary engine of the present invention taken along the line  3 — 3  of FIG. 1, illustrating the rotating center members forming ½ the toroidal cavity, all other elements being in dashed lines; 
     FIG. 4 is an exploded view of the toroidal rotary engine of the present invention taken in the direction of the arrow labeled  4  in FIG. 3; 
     FIG. 5 is a cross-sectional view of the toroidal rotary engine of the present invention taken along the line  5 — 5  of FIG. 1 illustrating the center rotating members and outer stationary members, all other elements being shown in dashed lines; 
     FIG. 5A is a cross-sectional view of the toroidal rotary engine of the present invention taken along the line  5 — 5  of FIG. 1 illustrating the spring loaded pins; 
     FIG. 6 is an exploded view of the rotating and stationary members members of the toroidal rotary engine of the present invention taken in the direction of the arrow labeled  6  in FIG. 5; 
     FIG. 7 is a cross-sectional view of the toroidal rotary engine of the present invention taken along the line  7 — 7  of FIG. 1, showing the connections of the upper external gear and internal output shaft; 
     FIG. 8 is a front perspective view of the first power train of the toroidal rotary engine of the present invention taken in the direction of the arrow labeled  8  in FIG. 7; 
     FIG. 9 is cross-sectional view of the toroidal rotary engine of the present invention taken along the line  9 — 9  of FIG. 1 illustrating the lower external gear attached to the outer shaft and two pistons attached to the upper center rotating member; 
     FIG. 10 is a front perspective view of the second power train of the toroidal rotary engine of the present invention taken in the direction of the arrow labeled  10  of FIG. 9; 
     FIG. 11 is a perspective view of the first power train and stationary member of the toroidal rotary engine of the present invention; 
     FIG. 11A is a perspective view of the first power train and stationary member of the toroidal rotary engine of the present invention showing the ports for receiving the spring loaded pins; 
     FIG. 12A is a diagrammatic view of the position of the first chamber during the intake cycle; 
     FIG. 12B is a diagrammatic view of the position of the first chamber during compression of the fuel air mixture; 
     FIG. 12C is a diagrammatic view of the position of the first chamber during the combustion cycle; 
     FIG. 12D is a diagrammatic view of the position of the first chamber during the exhaust cycle; 
     FIG. 13 is a cross-sectional view of the non-backward mechanism of the toroidal rotary engine of the present invention; 
     FIG. 14 is a cross-sectional view of the dynamic upper non-backward mechanism of the toroidal rotary engine of the present invention; 
     FIG. 14A is a top view of the dynamic upper non-backward mechanism of the toroidal rotary engine of the present invention; 
     FIG. 15 is a cross-sectional view of the dynamic lower non-backward mechanism of the toroidal rotary engine of the present invention; and 
     FIG. 15A is a top view of the dynamic lower non-backward mechanism of the toroidal rotary engine of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now descriptively to the drawings, in which similar reference characters denote similar elements throughout the several views, FIGS. 1 through 15A illustrate the rotary engine of the present invention indicated generally by the numeral  10 . 
     A perspective view of the rotary engine  10  is shown in FIG.  1 . The rotary engine  10  includes a housing  14  having a lower covering  16  and an upper covering  18  for housing the static and sequential moving structures of the rotary engine  10 . Extending from the housing  14  and through the upper covering  18  are an internal output shaft  24  and an external output shaft  26 . The internal output shaft  24  extends through the external output shaft  26 . The length of the internal output shaft  24  is greater than the length of the external output shaft  26  such that the internal output shaft  24  extends on either side of the external output shaft  26  when positioned to extend therethrough. The internal output shaft  24  includes an upper external gear  20  connected to an end thereof. A non-backward angular stop  51  extends from a side of the internal output shaft  24 . A lower external gear  22  is positioned at an end of the external output shaft  26  and an angular stop  52  is connected to the lower external gear  22 . The lower external gear  22  is positioned between the upper external gear  20  and the upper cover  18  of the housing  14 . 
     While a preferred structure for the angular stops is shown and described herein, those of ordinary skill in the art who have read this description will appreciate that there are numerous other structures for the angular stops and, therefore, as used herein the phrase “means for stopping movement of the first and second drive trains” should be construed as including all such structures as long as they achieve the desired result of stopping movement of the first and second drive trains, and therefore, that all such alternative mechanisms are to be considered as equivalent to the one described herein. 
     A cross-sectional view of the rotary engine  10  taken along the line  2 — 2  of FIG. 1 is illustrated in FIG.  2 . As can be seen from this figure, the housing  14  forms a cavity  15 . The external output shaft  26  extends partially into the cavity  15  wherein it is secured to a dynamic upper non-backward mechanism  28 . The internal output shaft  24  extends fully into the housing  14  wherein it is secured to a dynamic lower non-backward mechanism  30 . The internal output shaft  24  extends through and on either side of the external output shaft  26 . Positioned between the dynamic upper non-backward mechanism  28  and the dynamic lower non-backward mechanism  30  are upper and lower center rotating members  36  and  38 , respectively. The lower center rotating member  38  connects to rotate with the internal output shaft  24  to form a first power train. The lower center rotating member  38  is received within a lower outer stationary member  34  and a lower axial holder and rotary sliding face  31  is connected to the lower outer stationary member  34  and positioned between the lower outer stationary member  34  and the dynamic lower non-backward mechanism  30 . The upper center rotating member  36  connects to rotate with the external output shaft  26  to form a second power train. The upper center rotating member  36  is received within an upper outer stationary member  32  and an upper axial holder and rotary sliding face  29  is connected to the upper outer stationary member  32  and positioned between the upper outer stationary member  32  and the dynamic upper non-backward mechanism  28 . 
     The first power train is clearly illustrated in FIGS. 7 and 8 and includes the lower center rotating member  38  connected to first and second toroidal pistons  40 , the first and second toroidal pistons  40  being positioned on opposing sides of the lower center rotating member  38 . The lower center rotating member  38  is connected to rotate with the internal output shaft  24 , upper external gear  20 , internal shaft angular stop  51  and the dynamic lower non-backward mechanism  30 . The dynamic lower non-backward mechanism  30  includes a protrusion on a side opposite the connection with the internal output shaft  24 . The protrusion  60  is received in a recess  62  in the lower cover  16  of the housing  14  for retaining the first power train in position within the housing  14 . The internal output shaft  24  is secured to the lower center rotating member  38  for rotation therewith. The upper external gear  20  and internal shaft angular stop  51  are connected to the internal output shaft  24  and thus also rotate with the lower center rotating member  38 . The lower center rotating member  38  includes a groove  68  extending around a periphery of its top side  70  for receiving the first and second toroidal pistons  40 . 
     The second power train is clearly illustrated in FIGS. 9 and 10 and includes an upper center rotating member  36  connected to third and fourth toroidal pistons  40 , the third and fourth toroidal pistons  40  being positioned on opposing sides of the upper center rotating member  36  and between the first and second toroidal pistons  40 . The upper center rotating member  36  is connected to rotate with the external output shaft  26 , lower external gear  22 , external shaft angular stop  52  and dynamic upper non-backward mechanism  28 . The external output shaft  26  is secured to the upper center rotating member  36  and rotates therewith. The lower external gear  22  and external shaft angular stop  52  are connected to the external output shaft  26  and thus also rotate with the upper center rotating member  36 . The upper center rotating member  36  includes a groove  64  extending around a periphery of its bottom side  66  for receiving the third and fourth pistons  40 . The first and second power trains form first and second rigid structures. The lower center rotating member  38  is received within the lower outer stationary member  34  and the upper center rotating member  36  is received within the upper outer stationary member  32 . 
     The positioning of the upper and lower center rotating members  36  and  38  is illustrated in FIGS. 3 and 4. FIG. 3 is a cross-sectional view taken along the line  3 — 3  of FIG. 1 illustrating the remainder of the toroidal rotary engine  10  in dashed lines. As can be seen from these figures, the groove  64  extending around the upper center rotating member  36  is aligned with the groove  68  extending around the lower center rotating member  38  for receiving the first, second, third and fourth pistons therein. The first, second, third and fourth pistons  40  are positioned around the grooves  64  and  68  and separated by substantially 90°. Also extending through a side wall of both the upper and lower center rotating members  36  and  38  are lubrication veins  42  for lubricating the grooves thereby allowing the pistons  40  to slide therein. 
     FIG. 6 illustrates an exploded view of the rotating and stationary members positioned within the cavity  15 . The positioning of the first, second, third and fourth toroidal pistons  40  is also clearly seen from this view. A recess is provided extending through each of the upper outer stationary shaft  32 , the upper center rotating member  36 , the lower center rotating member  38  and the lower outer stationary member  34  for receiving the internal output shaft  24  therethrough. When assembled, the recess extending through each of the internal output shaft  24 , the upper outer stationary shaft  32 , the upper center rotating member  36 , the lower center rotating member  38  and the lower outer stationary member  34  are in alignment and the internal output shaft  24  is positioned to extend through the aligned recesses. The first groove  64  extends around a bottom side  66  of the upper center rotating member  36  and the second groove  68  extends around a top side  70  of the lower center rotating member  38 . The first, second, third and fourth pistons  40  are received between the first and second grooves  64  and  68 , respectively, as is clearly seen in FIGS. 3 and 4. An exhaust port  44  and an intake port  46  extend along a top side of the upper outer stationary member  32  and lower outer stationary member  34 . The exhaust port  44  and intake port  46  extend from an outside wall of both the upper outer stationary member  32  and lower outer stationary member  34  towards the recess in the center thereof and the upper and lower center rotating members  36  and  38 , respectively. The exhaust port  44  and intake port  46  on the upper outer stationary member  32  is in alignment with the exhaust port  44  and the intake port  46  on the lower outer stationary member  34  when the rotary engine  10  is assembled. 
     The positioning of the upper and lower center rotating members  36  and  38 , respectively, with respect to the upper and lower outer stationary members  32  and  34 , respectively, is illustrated in FIGS. 5 and 5A. As can be seen from this figure, the upper and lower center rotating members  36  and  38  are positioned within a central portion of the upper and lower outer stationary members  32  and  34 , respectively. The upper and lower outer stationary members  32  and  34  each also include a groove extending around a periphery thereof for receiving the first, second, third and fourth pistons  40  therein. The pistons  40  are positioned between the upper and lower center rotating members  36  and  38  and upper and lower outer stationary members  32  and  34 . 
     The upper outer stationary member  36  includes at least one recess  72  and the lower outer stationary member  38  also includes at least one recess  74  extending therethrough. The upper and lower outer stationary members  36  and  38  are positioned such that the recesses extending therethrough are in alignment. Extending through the aligned recesses for securing the upper and lower outer stationary members together are spring loaded connecting pins  58 . The spring loaded connecting pins  58  extend through the upper and lower outer stationary members  32  and  34  whereby a first end  76  of one of the connecting pins  58  is received by the dynamic upper non-backward mechanism  28  and a second end  78  of a second of the connecting pins  58  is received by the dynamic lower non-backward mechanism  30 . A first recess extending through the lower outer stationary member  34  includes a major opening  54  for receiving a spring  55  therein on one side and a minor opening  56  on the opposing end of the recess with a ledge  57  positioned within the recess. The spring  55  is received within the area of the recess between the ledge  57  and the major opening  54  to provide the spring loading for the connecting pin  58 . A second recess extending through the lower outer stationary member  34  is of uniform size throughout. The upper stationary member  32  also includes a first recess having a major opening  54  for receiving a spring  55  therein on one side and a minor opening  56  on the opposing end of the recess with a ledge  57  positioned within the recess. The spring  55  is received within the area of the recess between the ledge  57  and the major opening  54  to provide the spring loading for the connecting pin  58 . A second recess extending through the upper outer stationary member  32  is of uniform size throughout. The first recess of the lower outer stationary member  34  aligns with the second recess of the upper outer stationary member  32  and the second recess of the lower outer stationary member  34  aligns with the first recess of the upper outer stationary member  32  when the rotary engine  10  is assembled. When assembled, the spring  55  in the first recess of the lower outer stationary member  34  is positioned between the ledge  57  and a top side of the upper stationary member  32  surrounding the second recess extending therethrough and the spring  55  in the first recess of the upper outer stationary member  32  is positioned between the ledge  57  and a top side of the lower stationary member  34  surrounding the second recess extending therethrough. The connecting pins  58  add stability to the dynamic upper and lower non-backward mechanisms  28  and  30 . 
     FIGS. 11 and 11A illustrate the lower center rotating member  38  received within the lower outer stationary member  34 . Positioned on the top side  70  of the lower outer stationary member  34  are the exhaust port  44  and an intake port  46 . Matching exhaust and intake ports  44  and  46 , respectively, are provided on the bottom side of the upper outer stationary member  32  as can be seen in FIG. 6. A cavity  48  is also provided for receiving a spark plug  50  as shown in FIGS. 12A-12D. 
     The non-backward mechanism is illustrated in FIG. 13 with the upper non-backward mechanism  28  being illustrated in FIGS. 14 and 14A and the lower non-backward mechanism  30  being illustrated in FIGS. 15 and 15A. The non-backward mechanisms prevent the rotational members from falling into an improper/non functional position. Once a particular position is reached by a rotating member, the non-backward mechanisms will prevent the rotating members from moving back into the previous position as well as ensuring that the chambers will be formed in a perfect sequence to operate correctly. FIG. 13 illustrates a linear model of the upper and lower non-backward mechanisms  28  and  30  to illustrate their operation. FIG. 13 illustrates first and second plates  80  and  82  fixed to one another representing the first and second drive trains. A spring loaded pin  84  is shown engaging a lower plate  86  representing the lower non-backward mechanism  30 . An upper plate  88  representing the upper non-backwards mechanism  28  contacts the second plate  82 . Both the upper and lower plates  86  and  88  are able to move in the direction of the arrows labeled with the numeral  90 . The spring loaded pin  84  is free to move perpendicular to the lower and upper plates  86  and  88 . The lower plate  86  includes a saw-toothed top side  92  applying a force on the spring loaded pin  84  towards the upper plate  88  when the lower plate  86  moves in the direction of arrow  90 . The upper plate  88  includes a channel  94  for receiving the spring loaded pin  84  and a protrusion  96  for limiting the movement of the spring loaded pin  84 . As the lower plate  86  moves in the direction of the arrow  90 , the pin  84  will ride up one sawtooth of the top side  92  and eventually contact the protrusion  96 . Upon reaching the ledge defining the top of the sawtooth, the pin  84  will drop over the ledge and be compressed in order to pass by the protrusion  96  and move into a channel  98  on the other side of the protrusion  96 . Once past the protrusion  96 , the pin  84  will be prevented from returning to the channel it has left and thus returning to its previous position. This operation will continue for as long as the upper and lower plates  86  and  88  continue to rotate. A top and side view of the upper non-backwards mechanism  28  is illustrated in FIGS. 14 and 14A. A top and side view of the lower non-backwards mechanism  30  is illustrated in FIGS. 15 and 15A. These figures illustrate the grooves for a four cycle, four piston engine. The upper non-backwards mechanism  28  includes protrusions  98  and sawteeth  100  and the lower non-backwards mechanism  30  includes protrusions  102  and sawteeth  104 . 
     While a preferred structure for the non-backward mechanism is shown and described herein, those of ordinary skill in the art who have read this description will appreciate that there are numerous other structures for the non-backward mechanism and, therefore, as used herein the phrase “means for preventing the first and second drive trains from returning to a previous position” should be construed as including all such structures as long as they achieve the desired result of preventing the first and second drive trains from returning to a previous position, and therefore, that all such alternative mechanisms are to be considered as equivalent to the one described herein. 
     The operation of the rotary engine  10  will now be described with reference to the figures and specifically FIGS. 12A-12D which show a complete cycle of the engine. Shown in the figures are the four pistons  40 , four sealed chambers formed by the spacing of the four pistons  40  and the interaction of the pistons with three static elements, i.e. the exhaust port  44 , the intake port  46  and the spark plug  50 . 
     The beginning of the cycle is illustrated in FIG.  12 A. The pistons are labeled A, B, C and D and the four chambers formed thereby are labeled  1 ,  2 ,  3  and  4  for case of explanation. Opposing pistons A and C belong to the first power train and opposing pistons B and D belong to the second power train. The engine  10  will rotate in a clockwise direction. Each of the pistons A, B, C and D have an angular size of 40°, the angular size of the exhaust port  44  and intake port  46  is 10°. Chambers  2  and  4  have an initial angular size of 90° and chambers  1  and  3  have an initial angular size of 10°. Chamber  1  contains a compressed mixture of air and fuel, chamber  2  contains low pressure exhaust gasses and communicates with the exhaust port  44 , chamber  3  contains low-pressure exhaust gasses and communicates with the intake port  46  and chamber  4  contains a low-pressure mixture of air and fuel and is hermetically sealed. 
     To start the engine, a spark plug  50  ignites the compressed air and fuel mixture in chamber  1  which quickly burns the air and fuel mixture therein applying a pressure to pistons A and D. Piston D is prevented from moving due to the non-backwards mechanism and thus piston A is forced to move in a clockwise direction as indicated by the arrow labeled with the numeral  106 . As piston B belongs to the same power train as piston D, piston B is prevented from moving. As piston C belongs to the same power train as piston A, piston C will move with piston A in a clockwise direction. 
     As can be seen from FIG. 12B, chamber  1  has increased in size along with chamber  3  while chambers  2  and  4  have had a proportional decrease in size. As chamber  2  contracts, the low pressure exhaust gasses therein are caused to flow through the exhaust port  44 . As chamber  3  expands, a suction is created drawing a fresh mixture of air and fuel in through the intake port  46 . The expansion of chamber  3  causes chamber  4  to contract thereby compressing the air-fuel mixture therein and greatly increasing the power that can be extracted therefrom. As pistons A and C move clockwise, the internal output shaft  24  is caused to rotate thereby rotating the upper external gear  20 . 
     FIG. 12C illustrates the operation of the engine once chambers I and  3  reach an angular size of 90°. At this point, chambers  2  and  4  reach an angular size of 10°. The internal shaft angular stop  51  contacts the output shaft angular stop  52  at this point preventing further rotation of the first power train and preventing the size of the chambers from changing further. 
     At this point, the chambers have rotated to move one position ahead such that chambers  1 ,  2 ,  3  and  4  now occupy the positions previously held by chambers  2 ,  3 ,  4  and  1  respectively as is illustrated in FIG.  12 D. Chamber  1  now contains low-pressure burned gas that will flow through the exhaust port  44  as the chamber contracts. Chamber  2  includes low-pressure exhaust gas and will be filled with a fresh mixture of air and fuel from the intake port  46  as the chamber expands. Chamber  3  includes a low-pressure fuel-air mixture which will be compressed as the chamber contracts and chamber  4  includes an already compressed air-fuel mixture that will be ignited by the spark plug and burn. Upon ignition of the spark plug  50 , pistons A and C will be forced to remain in position by the action of the pressure and non-backward mechanism. Pistons B and D will be forced to move clockwise by the increasing pressure in chamber  4  caused by the burning of the air-fuel mixture. The movement of pistons B and D causes the second power train to rotate causing the external shaft  26  to apply a rotational force to the lower external gear  22 . Rotation of the external output shaft  26  and the lower external gear  22  will cease upon contacting of the angular stops  51  and  52 . This sequential movement of the first and second power trains will continue with the first and second power trains prevented from moving in a counterclockwise direction. 
     From the above description it can be seen that the rotary engine of the present invention is able to overcome the shortcomings of prior art devices by providing a rotary engine which is smaller, lighter, more completely free of vibration, cheaper, and mechanically simpler than the reciprocating linear internal-combustion engine. The toroidal rotary engine including a simple control mechanism, an acceptable sealing of the sliding surfaces involved, and a reliable and simple connection between the toroidal pistons and output shaft. The toroidal rotary engine also allows the fitness of a two or a four-stroke cycle with a spark-ignition or a compression-ignition system. Furthermore, the rotary engine of the present invention is simple and easy to use and economical in cost to manufacture. 
     It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
     While certain novel features of this invention have been shown and described and are pointed out in the annexed claims, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.