Abstract:
A rotary machine is provided, having a stator forming a chamber for a rotor, the stator having two sidewalls defining opposite sides of the chamber and a substantially continuous, circumferentially extending inner wall, and at least one inlet and outlet. A rotor and stator define two cavities at opposite ends of the chamber. The rotor has at least two radially extending slots and at least two radially movable vanes having first and second primary rollers and first and second secondary rollers mounted on a radially inward section of the vane. Two roller cam devices are each provided on a respective one of the stator side walls and are positioned centrally adjacent opposite sides of the rotor. In use, outer tips of the vanes slidingly engage the inner wall of the stator. The primary rollers limit outward vane movement due to centrifugal forces. Secondary rollers limit and control inward vanes movement.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of, and claims priority to, co-pending International Application PCT/CA2010/000559, having an international filing date of Apr. 14, 2010; and published as WO/2010/118518 on Oct. 21, 2010; which in turn claims priority to U.S. Provisional Patent Application 61/169,769; filed Apr. 16, 2009. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     TECHNICAL FIELD 
     The present disclosure relates generally to the field of rotary engines, pumps and compressors, in particular, a rotary machine with roller controlled vanes. 
     BACKGROUND OF THE INVENTION 
     A wide variety of rotary type engines and compressors are known in their respective arts. One reason for the development of rotary type engines is that in some respects they are more efficient than the well-known internal combustion engines which employ a plurality of pistons each disposed within a cylinder and connected to a crankshaft through a connecting rod. For instance, a great deal of heat and mechanical energy is wasted during the transfer of the linear, reciprocating motion of the piston to the rotating motion of the crank shaft. 
     A variety of rotary engines have been developed which employ sliding vanes mounted in slots in the rotor. One such rotary power device is described in U.S. Pat. No. 6,684,847 issued Feb. 3, 2004. The vanes are equally spaced about the rotor and divide the rotor chamber into discrete cavities. As the rotor returns, the vanes follow the wall contour of the motor chamber so that the cavities rotate with the rotor and expand and contract as the rotor turns. Each vane includes a vane plate portion, a pin fixable to the base of the vane and protruding through slots in the sides of the rotor, and cam follower rollers rotatably mounted at the outer ends of the pin and engaging guide cam grooves formed in side plates of the engine. As the rotor spins, the vanes reciprocate radially outward and inward relative to the rotor with the motion of the vanes being controlled by the cam grooves so that the vane tips come close to contacting the inner wall of a middle portion of the external stator. 
     Published PCT Patent Application No. WO 2007/062116 also describes a rotor having a number of radially extending slots in which movable vanes are mounted. The rotor is mounted in a chamber formed in an engine block. Movement of each vane is controlled by means of cam rollers mounted on opposite side edges of each vane. The cam rollers engage cam devices which have inner and outer tracks with smaller rollers on each vane engaging the outer track and larger rollers engaging the inner track. In this engine construction, there are also rollers mounted in the rotor to rollably support each vane as it moves in and out of its slot in the rotor. 
     Although the internal combustion engine illustrated and described in the aforementioned PCT application has a number of advantages over prior art designs and is efficient in its operation compared to known prior designs, the present applicants have improved this rotary engine design to provide a better cam and cam roller construction for controlling the radial movement of the vanes, to provide a rotor which is easier and less expensive to construct and which enables the efficient mounting of support rollers for the vanes, and in the case where auto ignition of fuel in the engine is desired, by providing a pressure transferring arrangement in the block in a location between combustion and compression chambers. 
     SUMMARY OF THE INVENTION 
     In its most general configuration, the presently disclosed design advances the state of the art with a variety of new capabilities and overcomes many of the shortcomings of prior devices and methods in new and novel ways. In its most general sense, the presently disclosed rotary machine overcomes the shortcomings and limitations of the prior art in any of a number of generally effective configurations. 
     According to one embodiment of a rotary machine, such a rotary engine, pump or compressor, constructed in accordance with the present disclosure, the rotary machine comprises a stator forming a chamber for a rotor, this stator have two sidewalls defining opposite sides of the chamber and a substantially continuous, circumferentially extending inner wall. The stator has at least one inlet and at least one outlet. There is also a rotor mounted in the chamber for rotation about a central axis of rotation and defining with the stator two cavities at opposite ends of the chamber. The rotor has at least two radially extending slots evenly spaced about the central axis. At least two radially movable vanes are each mounted in a respective one of these slots and each has first and second primary rollers and first and second secondary rollers mounted on a radially inward section of the vane. The first primary and secondary rollers are mounted on a first side edge of their respective vane and the second primary and secondary rollers are mounted on a respective second side edge of their respective vane. Two roller cam devices are each provided on a respective one of the stator side walls and are positioned centrally adjacent opposite sides of the rotor. The roller cam devices each form primary and secondary camming surfaces for engaging and controlling radial movement of the primary and secondary rollers respectively. Their camming surfaces are formed inside the roller cam devices and the primary and secondary camming surfaces of each roller cam device are offset from each other in an axial direction and in a substantially radial direction relative to the axis of rotation. During operation of the rotary machine, outer tips of the vanes slidingly engage the circumferentially extending inner wall of the stator. The primary rollers limit outward movement of the vanes due to centrifugal forces acting on the vanes and thereby limit substantially transfer of the forces to the inner wall. The secondary rollers limit and control inwards movement of the vanes. In an exemplary version of this rotary machine, each roller cam device is detachably connected by threaded fasteners to its respective stator sidewall. During operation of the rotary machine, the primary rollers on each vane rotate in an opposite direction compared to the direction of rotation of the secondary rollers. 
     These and other aspects of the disclosed rotary machine will become more apparent to those having ordinary skill in the art from the following detailed description taken in conjunction with the drawings provided herewith. 
     Numerous variations, modifications, alternatives, and alterations of the various preferred embodiments, processes, and methods may be used alone or in combination with one another as will become more readily apparent to those with skill in the art with reference to the following detailed description of the preferred embodiments and the accompanying figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that those having ordinary skill in the art to which the present disclosure pertains will more readily understand how to make and use the subject invention, exemplary embodiments thereof will be described now in detail with reference to the drawings. Without limiting the scope of the rotary machine as disclosed herein and referring now to the drawings and figures: 
         FIG. 1  is a perspective view of an embodiment of an internal combustion engine according to the present invention, this view showing one side cover on one side of the engine block and a bottom side of the block; 
         FIG. 2  is another perspective view showing engine components which include a rotor and its central shaft, vanes mounted in the rotor, a side cover of the block, and a cam device; 
         FIG. 3  is a perspective view similar to  FIG. 2  but illustrating an alternate form of side cover forming one side of the engine; 
         FIG. 4  is an exploded view of the internal combustion engine of  FIG. 1 ; 
         FIG. 5  is an axial cross-sectional view taken along the line V-V of  FIG. 1  and taken through the axis of rotation of the rotor, this view showing two vanes mounted on opposite sides of the rotor; 
         FIG. 6  is another cross-sectional view of the engine of  FIG. 1 , this view being taken along the line VI-VI and showing oil passageways running from a bottom side of the engine block; 
         FIG. 7  is a cross-sectional schematic view illustrating the rotor, its surrounding chamber, and the control rollers of the vanes running on parallel tracks; 
         FIG. 8  is a perspective view of one of the cam devices shown with one of the rotor vanes with its two control rollers on one side running on cam tracks of the cam device; 
         FIG. 9  is a detail view showing a transverse cross-section of a portion of one cam device and two control rollers running on its two tracks; 
         FIG. 10  is an exploded view of a vane used in the engine of  FIG. 1 ; 
         FIG. 11  is an enlarged perspective view of a quarter section of the rotor with the vanes omitted, this view showing in an exploded manner rotor seal details and vane seal details; 
         FIG. 12  is a perspective view of a side cover for the engine block according to one embodiment; 
         FIG. 13  is a perspective view similar to  FIG. 12  showing an alternate form of side cover for the engine; 
         FIG. 14  is a perspective view of an exemplary version of rotor shaft made as a single piece; 
         FIG. 15  is an exploded view of a single vane and its control rollers, this view also showing supporting roller units on opposite sides of the vane; 
         FIG. 16  is a perspective view of the rotor illustrating the use of plugs mountable in cavities in the circumferential surfaces of the rotor; 
         FIG. 17  is an enlarged perspective detail view showing a section of one half of the rotor with two of the vanes mounted therein supported by roller bearings; 
         FIG. 18  is a perspective view of one embodiment of the engine block, this view being taken from one side of and from the top of the block and showing oil trenches formed on the bottom section of the inner wall of the block; and 
         FIG. 19  is another perspective view of the engine block, this view showing one side and the bottom of the block. 
     
    
    
     These drawings are provided to assist in the understanding of the exemplary embodiments of the rotary machine as described in more detail below and should not be construed as unduly limiting the rotary machine. In particular, the relative spacing, positioning, sizing and dimensions of the various elements illustrated in the drawings are not drawn to scale and may have been exaggerated, reduced or otherwise modified for the purpose of improved clarity. Those of ordinary skill in the art will also appreciate that a range of alternative configurations have been omitted simply to improve the clarity and reduce the number of drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The presently disclosed rotary machine  10  enables a significant advance in the state of the art. The preferred embodiments of the rotary machine  10  accomplish this by new and novel arrangements of elements and methods that are configured in unique and novel ways and which demonstrate previously unavailable but preferred and desirable capabilities. The description set forth below in connection with the drawings is intended merely as a description of the presently preferred embodiments of the rotary machine  10 , and is not intended to represent the only form in which rotary machine  10  may be constructed or utilized. The description sets forth the designs, functions, means, and methods of implementing the rotary machine  10  in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and features may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the claimed rotary machine  10 . 
     With reference generally to  FIGS. 1-19  a rotary internal combustion engine  10  and its various components are illustrated in  FIGS. 1 ,  2  and  4 ; with a variation in the engine design being illustrated in  FIG. 3 . In a number of respects this engine incorporates features of the rotary engine illustrated and described in applicant&#39;s published PCT Patent Application No. WO2007/062116, the description and drawings of which are incorporated herein by reference. 
     As seen well in  FIG. 1 , the engine has two inlet ports  12  located on opposite sides of the engine and also two exhaust ports  14  located on opposite sides of the engine. Although the illustrated engine has a pair of each of these ports, the present engine can also be constructed with a single inlet port  12  and a single exhaust port  14 , if desired. A fuel air mixture is delivered to the engine by means of an intake manifold  16  which can include a cylindrical, closed end pipe section  18  and two curved connecting pipes  20 ,  22 , each extending to a respective one of the inlet ports. A further intake conduit  24  can deliver the fuel/air mixture to the pipe section  18 . Exhaust pipes  26 ,  28  can be connected by bolts to the exhaust ports  14  and, as illustrated, both of these are supported by a mounting plate  30  at one end, this plate being mountable by bolts to a rigid support surface. 
     The engine  10  includes a non-rotating stator or housing  32  which includes a main engine block  34  to the sides of which can be detachably connected a first side cover  36  and a second side cover  38  which can be seen more clearly in  FIG. 2 . Each cover plate is formed with sets of fastener holes  40  for receiving fasteners such as bolts  42 , only some of which are shown in  FIG. 1 . The bolts extend into corresponding apertures  43  (see  FIG. 4 ) formed on each side of the block. Detachably mounted on the bottom side of the block is an oil collector  44  which, in the illustrated exemplary embodiment is formed on its outer surface with a series of cooling ribs  46 . This oil collector can be used for the purpose of collecting oil from the bottom side of the engine, for providing oil to the engine chamber, and also for conducting coolant to and from a water pump (not shown). Two coolant pipe connectors  48 ,  50  are provided on one side of the collector to connect coolant pipes which conduct coolant to and from the water pump. Two additional pipe connectors  52 ,  53  are located between the connectors  48 ,  50  and these are used to connect coolant pipes that conduct coolant to and from the engine through coolant ports  54 ,  56 . 
     Also shown in  FIG. 1  are two oil feed ports  58 ,  60  through which oil is fed to lubricate cam rollers as described hereinafter. Oil return lines are connected to two oil outlets  62 ,  64 . Mounted in the center of each engine cover is a cylindrical bearing cap  66  which protects an outer main bearing  134  for center shaft  70  that supports engine rotor  72  shown in  FIG. 2 . The cap includes a circular cover  74  held in place by bolts in holes  76 . The cap protects the bearing from dust and debris. Formed on one side of the cap is an oil feed port  78  through which oil can be provided to the main bearings which support the shaft  70 . 
     Each engine cover can be formed with a series of radially extending ribs  80  which extend to an oval-shaped cover section  82 . To reduce the weight of this cover section it can be formed with a number of elongate openings  84  between at least some of which can be formed a series of round openings  86  which accommodate threaded fasteners used to clamp the two covers  36 ,  38  to the central block  34 . 
     With reference now to  FIGS. 2 and 3 , it will be seen that the rotor  72  is substantially cylindrical and is formed with two or more radially extending slots  90  in which are reciprocally mounted plate-like vanes  92 . The illustrated exemplary rotor has eight slots  90  and eight vanes  92 . The rotor has a cylindrical surface  94  which is broken into sections by the slots. The rotor can comprise two round, half rotor sections  96 ,  98  which are detachably connected together by means of bolts  99 . The illustrated rotor has eight pie-shaped sections and in each side of each section are formed three countersunk fastener openings  100 , two of which are near the circumferentially periphery of the rotor and the third closer to the center of the rotor. Formed in each pie shaped section is a combustion recess  102 , one half of which can be formed in each of the rotor sections  96 ,  98 . There is one combustion recess formed between each pair of adjacent vanes. In the present engine, the area between the vanes along with the combustion recesses form variable chambers or cavities generally indicated at  104  and shown best in  FIG. 7 . These chambers, which vary in size as the rotor rotates, are used for several functions including combusting the air and fuel mixture as will be described later. 
     Detachably mounted adjacent each flat side of the rotor is a cam device  106 ,  108  which is generally oval shaped on its exterior. It has a central opening  110  through which the shaft  70  extends. This opening is formed in a flat outer wall  112  and formed in this wall are fastener holes  114  which are used to attach the cam device to the adjacent engine cover. There can be formed in both curved ends of the cam device a small oil feed hole  116  through which oil is fed to the interior of the cam device. The flat plate shown in  FIG. 2  is the second side cover  38  for the engine or it can be an additional protective plate (such as a steel plate) provided between the actual engine cover and the block  34  depending upon the particular engine construction desired. The plate  38  can be formed with a series of bolt holes  118  through which bolts for attaching an outer oval-shaped engine cover (shown in  FIG. 1 ) extend. The provision of an additional flat plate between the actual engine cover and the block has the advantage of enabling easy access to water jackets formed in the stator. Also formed in plate  38  is an intake port opening  120  and a somewhat larger exhaust port opening  122 . 
     The engine components shown in  FIG. 3  are substantially similar to those shown in  FIG. 2  except for the construction of the engine cover. This oval-shaped cover can be constructed as a single metal piece which is bolted to the engine block or it can be formed as two pieces joined together. If desired the cover can be cast as a single piece. If it is made of two pieces, these can comprise a flat steel plate section  124  and an outer aluminum section  125 . Extending around the cover are a series of fastener holes  126  through which the fasteners extend to attach the cover to the block. 
     Turning now to the exploded view of  FIG. 4 , the various components which make up the engine  10  will be described going from left to right. The two above described bearing caps  66  are at opposite sides of the figure. Shown next to the bearing cap  66  on the left is a shaft seal  130  followed by a snap ring  132  used to fix the position of the outer bearing. The outer main bearing  134  for the rotor shaft is located adjacent to a bearing pre-load cup  136  which helps to eliminate backlash on the bearing and which is held by bolts. Next to this cup is an interior shim plate  138  which can be made of steel. The shim plate forms a protective surface against which set screws can push. Between the shim plate and the engine cover is a second shaft seal  140 . The oval-shaped cover  35  shown in  FIG. 4  has incorporated therein a cooling jacket, that is, a series of passageways through which coolant can flow to help cool the engine from this side. 
     Adjacent to the oval-shaped cover  35  is a separate, flat plate  37  which is used to seal this side of the engine block, and which, as shown, is oval shaped. However, it will be understood that the plate will be shaped to fit the exterior contour of the engine block, whatever that contour may be. As indicated, instead of being a separate plate  37 , it can be formed as a single piece which combines the oval-shaped cover  35  with the plate. The plate  37  is formed with an oval-shaped central opening  142  into which the adjacent cam device can be mounted. Shown in the middle of this opening is an inner main bearing  144  and next to this bearing is a further snap ring  146  to hold the inner bearing in place on the shaft. Shown between the cam device  106  and the rotor is a rotor spring assembly  148  described in detail below. Shown between the rotor and the block  34  is an optional separate liner  150  which can, for example, be a steel liner extending around the rotor chamber and providing a protective layer within the block which in many examples of the engine can be made of aluminum alloy. Mounted on top of the block is a set of four spark plugs  152  which can be of standard construction. Four ports  154  can be formed in the block to receive the spark plugs or ignitors. As explained in the aforementioned published application, the purpose of the plurality of plugs is to enable an air-fuel mixture to be ignited at different points during the rotation of the rotor as the speed of rotation of the rotor changes. 
     Inserted inside the bottom section of the block and connected to the oil collector  44  is an oil feed and return block  156 . Shown at the top of the collector  44  are two larger openings  158  for coolant flow into and out of the block  34 . Located between these openings is a smaller hole  160  which is used to feed oil to the rotor chamber while holes on opposite sides of the hole  160  are provided for oil being collected from the rotor chamber, that is returning from this chamber. It will be understood that the engine block  34  has incorporated therein (in a manner known per se in the art) a water cooling jacket in which coolant flows to cool the block. The block illustrated in  FIG. 4  is a closed block with the passageways of the cooling jacket not being visible. 
     Alternatively, the block can be an open block wherein the passageways for coolant are closed off by the engine covers on opposite sides of the block which are suitably sealed.  FIGS. 5 and 6  are axial cross sectional views of the engine which show additional features thereof. Shown in  FIG. 5  are elongate threaded fasteners  162  which are used to clamp and secure the two engine covers to the block  34 . A nut  164  can be used at one or both ends of each fastener. A series of coolant passageways  166  and  168  can be seen formed in the two engine covers and further coolant passageways  170  are shown in the block  34 . Bolts  77  for holding each bearing cap  66  in place can be seen. In  FIG. 5 , the two illustrated vanes  92  are fully extended while the vanes are shown in their radially innermost position in  FIG. 6 . 
     An exemplary construction of the rotor shaft  70  can be seen from  FIGS. 5 ,  6  and  14 . The shaft is formed with a central section  172  of wider diameter on which a series of flat-topped lugs  174  are formed. These lugs engage co-operating notches formed about the central hole of the rotor and thus the rotor is prevented from rotating relative to this shaft. About one half  176  of this shaft is solid steel while the other half  178  has a central oil feed passageway  180  formed therein. The passageway  180  is threaded at end  182  to receive a plug (not shown). Oil is fed into the shaft through oil inlet  184  located in the side of the shaft and in one of the caps  66 . Lubricating oil is fed into the chamber  186  of the cap. This oil lubricates not only the main shaft bearings but is also fed into passageways in the rotor in order to lubricate the rollers for the vanes as described further below. Also a bypass hole (not shown) is provided at  190  to feed oil from the interior of the cap to the inner main bearing. Power can be delivered through the solid half  176  of the shaft which is the stronger half since it has no central passageway. 
       FIG. 6  is a central cross section of the engine taking in the direction of the shorter side of the engine. This view shows a cross section of the oil collector  44 . Extending from the oil collector and into the bottom side of the block is an oil feed passageway  192  and located on opposite sides of this central passageway are two oil return passageways  194 ,  196 . Also visible are bolts  198  used to detachably connect the oil collector to the bottom of the block. A series of closely spaced, small holes or passageways  200  evenly distribute oil across the width of the rotor chamber. The inner ends of these passageways  200  are visible in  FIG. 18 . These passageways provide good lubrication to the vane tips and the vane seals. Also, visible in  FIG. 6  are oil inlets  202  through which oil can be fed under pressure into the bearing caps  66 . The joint between each bearing cap and the engine cover is sealed by an annular gasket  204 . 
       FIG. 7  illustrates that the stator including the engine block  34  forms a substantially oval-shaped chamber indicated generally at  210  for the rotor  72 . The block forms a substantially continuous, circumferentially extending inner wall  212  along which the vane tips move as the rotor rotates. For present purposes, it can be assumed that the rotor is rotating in the counter clockwise direction indicated by the arrow A shown in  FIG. 7 . The engine  10  can be considered as having a first axis  214  and a second axis  215  perpendicular to the first axis with both axes being perpendicular to the central shaft  70 . These axes effectively divide the engine into four quadrants including a first quadrant  216 , a second quadrant  218 , a third quadrant  220  and a fourth quadrant  222 . Each quadrant performs a different part of the cycle of the engine operation with the first quadrant  216  being the intake cycle wherein the air/fuel mixture is drawn into the engine through intake openings  120  by the vane or vanes passing through this quadrant. The second quadrant is where the compression cycle takes place with the air/fuel mixture being compressed as the vane passing through this quadrant moves radially inwardly. The third quadrant  220  is where the power cycle occurs as the exploding mixture forms rapidly expanding gases to push against the extended vane passing through this quadrant. The fourth quadrant  222  is where the exhaust cycle takes place and the exhaust gases are pushed by the vanes out through the outlet or outlets  122 . 
     It will be seen from  FIG. 7  that the shape of the inner wall  212  is not a simple oval shape in an exemplary version of the engine. There are slight, smoothly rounded inwardly extending wall sections  224 ,  226  on opposite sides of the rotor chamber. Only the inwardly extending wall section  226  is functionally significant from the standpoint of engine operation with the other wall section  224  being provided simply for better engine balance which helps prevent vibration. The reason for the rounded wall section  226  in the third quadrant  220  and in the region where the spark plugs are located is to increase the thermo-dynamic efficiency of the engine by reducing the rate of volume increase during a combustion cycle thereby reducing the rate of heat loss. 
     Because of these advantages, this unique shape for the block chamber promotes a more complete combustion of the air/fuel mixture. The shape also reduces negative torque by keeping the trailing vane recessed in the rotor for a longer period of time while allowing the leading vane to extend and turn the rotor from the expanding gases pressing on the surface of the leading vane. 
     Referring now to  FIG. 8 , this figure shows in perspective one cam device  106  and one of the vanes  92 . Each vane  92  has first and second primary rollers  230  and first and second secondary rollers  232  mounted on a radially inward section  234  of the vane. In the exemplary vane shown there are two sections  234  separated by a U-shaped gap  236 . The first primary and secondary rollers are mounted at a first side edge  238  of the vane  92  while the second primary and secondary rollers are mounted at an opposite second side edge  240  of the vane. Each pair of rollers  230 ,  232  is mounted on a cam roller pin  242  which is shown separately in  FIG. 10 . Each pin can be formed with an enlarged head  244  to hold the adjacent roller on the pin. The primary rollers  230  keep the vane from flying outwards from centrifugal force (which would damage the engine block) and the secondary rollers  232  keep the vane from being driven inwards from combustion pressure and the profile of the cam at engine start up. Mounting each primary roller and a secondary roller on a single shaft reduces manufacturing costs. This also helps eliminate the need for additional holes in the vane which increases the strength of the vane and provides more space in the vicinity of the cam device. 
     As will be seen from  FIGS. 8 and 9  as well as  FIGS. 5 and 6 , in this engine the cam rollers are located on the inside of their respective cam device  106 ,  108 . As each of these cam devices is of similar construction only the construction of the interior of the cam device  106  will be described. The cam device is formed with a primary roller track at  246  and a secondary roller track  248  which is opposite the track  246  and formed by interior wall  254 . The surface  250  located opposite the track  248  is only a clearance surface that neither roller engages. It will be appreciated that the primary roller track  246  is offset from the secondary roller track  248  in an axial direction relevant to the axis of rotation of the rotor. The primary roller track  246  is also offset from clearance surface  250  in an axial and radial direction relevant to the axis of rotation of the rotor (see  FIG. 9 ). The primary rollers  230  roll simultaneously in an opposite direction compared to the secondary rollers during the progress of the vane around the rotor chamber. The reason for the use of both the primary rollers and the secondary rollers as opposed to a single pair of rollers should be clear from the fact that a roller bearing cannot roll in a trench while in contact with both walls of the trench. When this happens the roller will just skid without spinning and will act like a pin in a track. A pin in a track would require positive oil pressure in order to ride on an oil film to keep it from burning up from excessive friction. If only one roller is used in a cam trench, then there would have to be clearance between the roller and the walls so that at no point in time during rotation will the roller touch both walls at the same time. Such a clearance would result in loss of full controllability of the vane in that the vane could move closer or further from the engine block surface. By using both primary and secondary rollers and two tracks, there is very little end play on each vane as it rotates with the rotor. This cam construction allows full control of each vane at all times during the rotation of the rotor. The cam devices  106 ,  108  are made of hardened aluminum alloy in an exemplary embodiment, this alloy being anodized to the hardness required by the cam roller bearing. 
       FIG. 10  provides further details of the construction of each rotor vane  92 . In particular it will be seen that the radially inward section  234  of the vane is formed with two holes  256  each adapted to receive a section of a corresponding cam roller pin  242 . The pin is formed with a circumferentially extending slot  258  near its inner end. A small spring pin  260  extends through hole  262  formed in the vane and along one side of the slot  258  in order to lock the roller pin in place. If desired, a number of holes  264  can be formed in the vane in order to reduce the weight thereof without substantially compromising the strength and durability of the vane. In an exemplary form, the rollers  230 ,  232  are provided with roller bearings  266  to facilitate their free rotation on the roller pin. It is also possible to construct the rollers using solid bearings in some circumstances. 
     Also shown in  FIG. 10  are two full corner seals  270 ,  272  each of which forms a right angle and each of which has a reduced end section  274  which overlaps with the end section of the other seal. An exemplary form of each corner seal is made of hardened steel but it is also possible to construct these seals from ceramic or other suitable, known engine seal materials. These two seals are spring biased by means of three wavy leaf springs  276 ,  277 ,  278 . These springs together with the seals are accommodated in side grooves  280  formed on opposite sides of the vane and a vane tip groove  282  (seen best in  FIG. 15 ). This improved vane seal construction has several advantages including the following: 
     (1) it reduces a number of vane seal parts; 
     (2) it allows thermal expansion of the two corner seals without losing contact area, thus maintaining pressure; and 
     (3) the use of corner seals reduces the seal gaps preventing blow by of gases and reduces the chance of seal chatter by absorbing vibrations through the side leg  284  of each corner seal. 
       FIG. 11  illustrates details of the aforementioned rotor seal assembly  148 . The assembly includes an annular rotor seal  286 , an annular shim  288 , and an annular wavy spring  290  which biases the seal towards the rotor. The rotor seal  286  fits into a series of arcuate grooves  292  formed about its respective side of the rotor. The rotor seal in the illustrated embodiment is formed with alternating small recesses  294  and substantially larger and longer recesses  296 , both types of recesses facing the side of the rotor. The purpose of the recesses  294  is to provide an engagement between the seal and the rotor which is formed with catches or protuberances  298  in the grooves  292  which engage these recesses. In this way the rotor seal is prevented from moving in the circumferential direction relative to the rotor. The purpose of the longer recesses  296  is to accommodate the side edges of the vanes. The exemplary recesses  296  are formed with slightly sloping surfaces  300  that extend in a circumferential direction from the center of the recess. Matching sloping side edge surfaces  302  (see  FIG. 15 ) are formed on each side edge of each vane in the region of the corner seal. Note also that each recess  296  is slightly longer than the width of the respective vane in order to accommodate vane scraper seals described below. It will be understood that the rotor seal slides along the shim  288  and a notch (not shown) can be formed in the shim to maintain it in position on the side cover of the engine which has a cooperating protuberance. The wavy spring  290  maintains the shim in engagement with the surface of the seal. 
       FIGS. 11 and 15  also illustrate the provision of straight scraper seals  310  and straight compression seals  312  which engage the two opposite sides of each vane. Both the scraper and compression seals are mounted near the circumference of the rotor so as to be adjacent the sides of their respective vane. Transversely extending grooves are provided at  314  (see  FIG. 16 ) in the rotor to accommodate these seals and their wavy springs  316 . Each compression seal is located radially outwardly relative to its respective scraper seal. The scraper seals are made of spring steel and are made with a slight wave so that they are able to compress longitudinally when the engine heats up. The compression seals  312  interlock with the rotor seal  286 . Small pockets (not shown) are machined out of the rotor seal so that both ends of each seal  312  “seat” inside respective pockets in the rotor seals. 
       FIG. 15  also illustrates the roller support mechanism for each vane and its construction. In the exemplary version shown, opposite sides of the vane are rollably supported by supporting rollers  320  with four or more on each side of the vane. These rollers are supported on elongate support pins  322 . These pins extend through a roller supporting base  324  which is made as a single piece. If desired, more than four supporting rollers  320  can be mounted on the base  324 , for example to provide additional support to the vane when required. Thus on the base  324  on the right side of  FIG. 15 , there are six supporting rollers  320  mounted on the base, two at one end and four at the opposite end. Inner and outer ends of the base are formed with pin supporting lugs  330  in which are formed pin holes  332 . It will be appreciated that by constructing the rotor of two half sections, it becomes reasonably easy to mount these supporting rollers  320  and their respective bases  324 . These rollers and their bases can be first mounted in a lower half section by inserting ends of the pins  322  in holes  334  (see  FIGS. 11 and 16 ) formed in the rotor. The rollers  320  and their bases  324  are accommodated in recesses  336  formed in each pie-shaped section of the rotor on opposite sides thereof. The opposite ends of the pins  322  are then mounted in the holes  334  of the upper half section when it is joined to the lower half section. There is no need to preload the rollers  320  onto the vanes and this reduces the costs of making the engine/machine. The vanes are sized to fit precisely in the space between the opposing rollers. If desired, each base  324  can be formed with slightly tapered sidewalls that meet at a centerline of the base that passes through a central hole  328 . This taper is for ease of installation. 
     The supporting rollers  320  can be lubricated by oil through a series of passageways formed in the rotor and in their respective base  324 . In particular lubricating oil can be fed through the central hole  338  formed in each base, this hole feeding lubricant through another central, interconnecting passageway  340  that is connected with passageways (not shown) that extend to the holes  332  in which the support pins for the rollers are mounted. Lubricating oil is delivered to the hole  338  by means of a Y-shaped oil passageway  344  (see  FIG. 17 ) formed in each pie-shaped section of the rotor. One half of each passageway  344  is formed by each half section of the rotor so that when the two half sections are connected together the complete passageway  344  is formed. Two short branches  346  of the passageway extend to the center hole  338  of two roller bases  324 . Oil is delivered to the radially inner end of each passageway  344  by means of the central shaft  70  and its central oil outlet ports  348  (see  FIG. 14 ). 
       FIG. 12  illustrates one embodiment of a side cover for the rotary engine  10 . The side cover is formed with a series of the aforementioned bolt holes  40  in each of its four corners, these being used to attach the side cover to the block  34 . Formed in a central section of the cover  36  is a groove  350  in which is mounted one of the rotor seal assemblies  148 . Formed on a lower side of this groove is an oil receiving trench  352  which collects oil when the engine is operating. Formed in the center of the cover is a generally oval-shaped recess  354  which is sized to closely accommodate one of the cam devices  106 ,  108 . Located in the bottom of this recess is a central, cylindrical cavity  356  in which is mounted the inner main bearing of the rotor shaft. To lighten the weight of the cover, holes  360 ,  362  can be formed in the cover, the formation of which removes unnecessary material. Several holes  364  formed in the bottom of the recess  354  are used to attach the cam device by bolts. 
       FIG. 13  illustrates the details of the central portion of the engine cover shown in  FIG. 3 . As can be seen from a comparison of  FIGS. 12 and 13 , the two engine covers are similar in their construction except for the differences already noted above. As indicated, the cover can be made as a single metal piece or it can be made of two pieces including a flat plate section  124 . If made as two pieces, the plate section  124  can be formed from steel plate while the outer cover section  125  is formed of aluminum alloy. 
       FIG. 14  illustrates the exterior of the shaft  70  in an exemplary form. This shaft can be made from a single steel piece and is formed with a central shaft section  172  having the lugs  174  thereon. The shaft can be formed with annular recesses at  370  and  372  to accommodate snap rings  132 ,  146  for holding the main shaft bearings in place. 
       FIG. 16  illustrates the optional feature of changing the shape and size of the combustion recesses  102  formed about the periphery of the rotor. By changing the shape and size of these combustion recesses one can vary the amount of displacement and compression achieved in the engine  10 . In particular, the size of the compression recesses can be varied by the use of plugs  375  which can either reduce or substantially eliminate the compression recesses. The plugs can be attached by means of threaded fasteners  376  which extend through holes in the plugs and are threaded into holes  378  formed in the bottom of each recess. If the engine is to operate with diesel fuel, the size of the combustion recesses can be changed so as to increase compression to combust the diesel fuel properly, eliminating the need for one or more spark plugs. The engine can also be adapted for use with hydrogen or hydrocarbon fuel. 
       FIG. 18  illustrates the engine block  34  by itself and visible in this view is its oval-shaped inner wall  212 . The bottom side of the block is indicated at  380 . Formed near the bottom side on the inner wall are a pair of V-shaped trenches  382 ,  384 . These oil trenches deliver oil to exit ports  386 . The purpose of these trenches is to prevent oil from pooling in the bottom of the block chamber when the engine is turned off. Any oil that collects at the bottom of the block chamber when the engine is shut off is directed by the trenches into the oil feed and return block  156  described above and shown removed from inside the block in  FIG. 19 . This small block, which is mounted in the wall of the block in a suitable opening, directs the oil into the main oil reservoir for the engine. A gasket or seal  390  is used to seal the joint between the block  156  and the engine block. 
       FIG. 19  illustrates one version of the engine block  34  which can be made of aluminum alloy with suitably heat treated inner surfaces that will withstand the high temperatures which are generated by the engine operation. This view illustrates the use of two bleed off trenches  392  formed on an upper section of the inner wall of the block. These trenches are primarily provided for HCCI application wherein HCCI stands for Homogeneous Charge Compression Ignition. Although diesel is one form of fuel that is used in this type of engine, other forms of fuel are also possible. In this type of engine, when the autoignition temperature of the fuel is reached, the fuel will spontaneously ignite causing detonation. In order to reduce the pre-ignition condition, the trenches  392  are cut into the inner wall and are located between the combustion and compression chambers for the purpose of allowing pressure bleed off. This pressure bleed off, in addition to preventing premature ignition, will also cause turbulence in the fuel mixture, which is desirable for complete combustion. 
     Although the present invention has been illustrated and described as embodied in various exemplary embodiments, e.g. embodiments having particular utility as in internal combustion engine, compressor etc. It is to be understood that the present invention is not limited to the details shown herein, since it will be understood that various omissions, modifications, substitutions and changes in the form and details of the disclosed machines and components and their operations may be made by those skilled in the art without departing in any way from the spirit and scope of the present invention. For example, those of ordinary skilled in the art will readily adapt the present disclosure for various other applications without departing from the spirit or scope of the present invention. The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or acts for performing the functions in combination with other claimed elements as specifically claimed.