Patent Publication Number: US-2013228150-A1

Title: Rotary, Internal Combustion Engine

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part application of U.S. patent application No. 12/637,595, filed Dec. 13, 2009, which is hereby incorporated by reference in its entirety. 
    
    
     NOTICE OF COPYRIGHTS AND TRADE DRESS 
     A portion of the disclosure of this patent document contains material that is subject to copyright protection. This patent document may show or describe matter that is or may become trade dress of the owner. The copyright and trade dress owner has no objection to the facsimile reproduction by anyone of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright and trade dress rights whatsoever. 
     BACKGROUND 
     1. Field: Rotary, internal combustion engines. 
     2. General Background and State of the Art: Internal combustion engines burn fuel in their combustion chambers in the presence of oxygen (usually from air). Burning generates high temperature and pressure gases, which expand and apply force against movable engine parts. Movement of the parts produce mechanical energy. Thus, an internal combustion engine converts potential chemical energy in the fuel into kinetic mechanical energy. Therefore, they provide the power for practical mechanical work to move vehicles and run pumps and other equipment. 
     Internal combustion engines fall into two principal categories, intermittent and continuous. Piston engines, either four-stroke and two-stroke, are the most common intermittent engines. Less common rotary engines also are intermittent. Continuous combustion engines include gas turbines and jet engines. 
     Internal combustion engines find their most common use in vehicles including cars, trucks, busses, airplanes and ships. The ratio of the potential chemical energy of the fuel (normally gasoline or diesel fuel) to the weight of the fuel is high. Consequently, internal combustion engines can travel long distance while carrying all their fuel. 
     Gasoline piston engines are among the least efficient internal combustion engine, only about 25%-30% efficient. Direct injection diesel engine may be about 40% efficient, at least at lower RPMs. Gas turbines are among the most efficient—approximately 60% efficient at high revolutions. However, gas turbines are inefficient at low revolutions. Because most land vehicle engines operate close to idle or well below maximum RPM, gas turbines usually are impractical for most land vehicles. 
     Rotary internal combustion engines surfaced in the early 1900s. See Hanley, U.S. Pat. No. 1,048,308 (1912). The Wankel rotary engine, which was developed beginning in the 1960s, became commercialized. See U.S. Pat. Nos. 2,938,505, 3,306,269, 3,373,723, 3,793,998, 3,855,977, 3,923,013 and 4,072,132. The Wankel engine is an internal combustion engine that uses a rotary design instead of reciprocating pistons to convert the energy of expanding combustion gases into rotating motion. Its four-stroke cycle takes place in a space between the inside of an oval-like epitrochoid-shaped housing and a rotor that is similar in shape to a Reuleaux triangle. The public often refers to the Wankel engine as the “rotary engine,” but rotary engines may have other constructions. 
     Internal combustion engines compress an air-fuel mixture in a combustion chamber and ignite the fuel by an electric spark or ultra high compression. The resulting combustion expands the gases to transform chemical energy into mechanical energy. 
     The combustion chamber in a gas turbine is between two sets of opposing fan blades. The fan blades compress the air mixture. When fuel is introduced and ignited, the combustion products expand against downstream fan blades causing the blades to rotate. The energy from the blade rotation drives the vehicle or other device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is perspective view of the rotary engine. 
         FIG. 2  is an exploded view of the rotary engine. 
         FIG. 3  is an exploded view of the rotary engine&#39;s power module. 
         FIG. 4  is front cut-away view of the rotary engine. 
         FIG. 5  is a front view of the internal parts of the rotary engine&#39;s rotor. 
         FIGS. 6   a  and  6   b  are partial front views of the rotary engine&#39;s rotor. 
         FIG. 7  is perspective view of the rotary engine&#39;s rocker. 
         FIG. 8  is perspective view of the small crankshaft of the rotary engine. 
         FIG. 9  is a perspective front view of the housing of the rotary engine&#39;s rotor. 
         FIG. 10  is a perspective rear view of the housing of the rotary engine&#39;s rotor showing the cooling jackets. 
         FIG. 11  is a perspective view of the rotary engine&#39;s rotor. 
         FIG. 12  is a perspective view of the main crankshaft shaft. 
         FIG. 13  is a front view of a two-cycle rotor. 
         FIG. 14  is a perspective view of an engine using two rotary engines. 
         FIGS. 15 and 16  are perspective views of alternative ring plates of the rotary engine. 
         FIG. 17  is a perspective view of a replacement part for part of the rotor. 
         FIG. 18  is a perspective view of a seal used in the device. 
         FIG. 19  is a perspective view of a housing for a compressor used with the rotor. 
         FIG. 20  is a perspective view of an alternative spur gear. 
         FIG. 21  is a perspective view of another alternative rotor for the rotary engine. 
         FIG. 22  is a perspective view of a ring seal assembly for use with the ring plate shown in  FIG. 15 . 
         FIG. 23  is a top perspective view of a crossover seal for use with the rotor shown in  FIG. 5 . 
         FIG. 24  is a bottom perspective view of the crossover seal shown in  FIG. 23 . 
         FIG. 25  is an exploded view of the crossover seal shown in  FIG. 23 . 
         FIG. 26  is an exploded view of an exemplary housing body and sleeve, such as the housing body shown in  FIG. 2 . 
         FIG. 27  is a perspective view of port shapes that can be used in the sleeve shown in  FIG. 26 . 
     
    
    
     When the detailed description discusses a reference numeral in one or more drawing figures, the element and reference numeral being discussed is visible in that drawing. The element also may be visible in other figures without its reference numeral to avoid crowding of reference numerals. 
     SUMMARY 
     A rotary engine has a rotor that has rockers pivoting in chambers inside an enclosed cylindrical housing. As each rocker pivots, it rotates an outer crankshaft. Each outer crankshaft has a spur gear that engages a stationary ring gear. Spur gear rotation causes the gears and the outer crankshafts to revolve around the ring gear. This causes the rotor to rotate. 
     As the rotor rotates, successive chambers are positioned at the intake, compression, ignition, and exhaust positions. In the intake position, the rocker pivots into its chamber to draw the air-fuel mixture into the chamber. The rocker pivots outward in the compression position. Igniting the fuel in the ignition position pushes the rocker inward, and the rocker moves outward again in the exhaust position to exhaust the combustion products. 
     DETAILED DESCRIPTION 
     Rotary engine  100  ( FIGS. 1 and 2 ) has the following principal components: (1) housing  200  for housing other components and for mounting in a vehicle or other device; (2) power module  300  and output  600 . See  FIG. 2 . 
     Housing  200  ( FIGS. 1 ,  4 ,  9  and  10 ) may include a generally cylindrical housing body  202  of 8620, 8514 or other steel alloy. Aluminum or other suitable materials also could be used. The housing has a cylindrical inner wall  204 . The inner wall also could be a steel insert inside an aluminum outer housing body. 
     The housing may be air- or water-cooled. If water-cooled, the housing body may have top and bottom water troughs  210  and  220  ( FIGS. 9 and 10 ). Top water jacket  212 , which covers the top water trough, has inlet  214  and outlet  216  ( FIG. 10 ). Likewise, bottom water jacket  222 , which covers the bottom water trough, has inlet  224  and outlet  226 . The inlets may receive coolant from a radiator or other heat exchanger, and the outlets return the coolant to the radiator. Hoses connecting the inlet and outlet to the radiator are not shown. The troughs may have vanes  218  and  228  of heat conductive material to transfer heat from the housing to the coolant. The vanes also may direct the coolant to flow from the inlet to the outlet. In addition, one could change the locations of the inlet and outlet. 
     Front plate  230  and rear plate  232  enclose housing  200  ( FIGS. 1 and 2 ). The plates may be 6061 aluminum or other suitable material. The terms “front” and “rear” are used with reference to the drawings, not necessarily with reference to a vehicle or another device in which the rotary engine mounts. Housing body  202  has circumferentially spaced bores extending into the front and back of the housing body. Only the bores  234  on the front are visible. See  FIGS. 2 ,  4 ,  9  and  10 . Bolts or other fasteners (not shown) extend through corresponding holes  236  in the front plate and lock into the bores. Housing body  202  may have openings and ports that are discussed in more detail below. 
     The front and rear plates  230  and  232  may include an oil ring seal groove  238  (only shown on plate  232  in  FIG. 2 ). Corresponding ring seals (see seal  532  in  FIG. 18 ) seat in the ring seal grooves to create a seal when the plates attach to housing body  202 . Gaskets (not shown) also may seal the plates to the housing body. Other devices or systems may be provided to prevent galvanic corrosion due to the dissimilar metals. 
     Power module  300  mounts within housing body  202 . See  FIGS. 2 and 4 . The power module includes rotary module or rotor  310  that rotates about an axis of rotation within the housing body. The rotor may be formed of  8620  or  8514  steel or ductile iron. The rotor may have four arms  312 ,  314 ,  316  and  318  ( FIGS. 5 ,  6   a ,  6   b  and  11 ). The distal end of each arm, e.g., end  320  of arm  312  ( FIGS. 5 ,  6   a  and  6   b ), has two short, spaced-apart extensions  322  and  324  ( FIGS. 6   a  and  6   b ). The outer faces  326  and  328  ( FIGS. 3 ,  6   a  and  6   b ) may have surfaces that conform to inside cylindrical wall  204  of housing body  202 . Pressure plates  330  ( FIG. 3 ), which may be  9254  steel, seat in the space between extensions  322  and  324 . Spring  332 , which may be made of Incoloy® alloy, urges the pressure plate  330  to push seals  306  and  308  ( FIG. 3 ) to seal against the inside cylindrical wall. The pressure plate seals and the arm extensions such as extensions  322  and  324  seal the distal ends of the arms to the inside cylindrical surface of the housing body. Remaining arms  314 ,  316  and  318  have similar arrangements. 
     Arms  312 ,  314 ,  316  and  318  may be formed from two plates  340  and  342  that extend outward from hub  344  ( FIG. 11 ) and form hollow space  336 . Only the plates that form arm  312  in  FIG. 11  are numbered. The hollow space is used by outer crankshafts as described below. In addition, having spaced-apart plates may decrease rotor mass and increase efficiency. 
     Plates for arms  312 ,  314 ,  316  and  318  may have aligned bores.  FIG. 11  shows bores  350 ,  352 ,  354  and  356  in plate  340 . Only bore  358  in plate  342  is visible. As  FIGS. 6   a  and  6   b  show, bores  350 ,  352 ,  354  and  356  align with corresponding bores in plate  342 , which are not visible in  FIGS. 6   a  and  6   b.    
     The space between one arm and its adjacent arm and inside cylindrical wall  204  of housing body  202  forms a chamber. Thus, chamber  360  ( FIG. 5 ) is formed between arms  312  and  318 , and the spaces between arms  312  and  314 ,  314  and  316  and  316  and  316 , form chambers  362 ,  364  and  366 , respectively. 
     One of four rockers  370 ,  372 ,  374  and  376  mounts for pivoting in each chamber  360 ,  362 ,  364  and  366 .  FIG. 3  shows rocker  376  exploded from the rotor,  FIG. 5  shows all the rockers in relation to rotor  310 ,  FIGS. 6   a  and  6   b  shows only two rotors moved between different positions, and  FIG. 7  shows details of the rocker. The rockers may be formed from  4032  aluminum or other appropriate material. 
     Pivot pin  380  extends through ridge  382  of each rocker ( FIG. 7  and only numbered for rocker  376  in  FIG. 5 ). The ridge mounts in rounded portion  384  of each arm  312 ,  314 ,  316  and  318 . The outer surface of the ridge cooperates with the surface of the rounded portion to seal the ridge and rounded portion intersection as the rocker pivots. Added structure may be provided to enhance the seal at the ridge such as a sealing member  428  ( FIG. 3 ) in groove  382  ( FIG. 7 ). The rocker may have a front groove  404  and side grooves, only one of which, groove  406 , is visible  FIG. 7 . Side compression seals  424  and  426  ( FIG. 3 ) mount in the side grooves and front compression seal  428  seats in the front groove. They may be 5254 steel. The side compression seals contact the inside of front ring plate  396  and rear ring plate  398  when the ring plates are mounted to the outside of rotor  310 . See  FIG. 3 . The front compression seal contacts the rocker face of each rotor arm, e.g., face  368  of arm  312  ( FIG. 5 ). The rocker faces may be arcuate around the axis of each pivot pin. The rocker faces also close off the space between the two plates. Seals  306  and  308  ( FIG. 3 ) may seat in circumferential grooves  334  of ring plates  396  and  398  (only the groove in ring plate  396  is numbered). Each seal may have inward facing portions  504  and  506  (only the portions on seal  306  is numbered in  FIG. 3 ). The inward facing portions contact each other to form a seal. The inward facing portions may extend from the circumferential grooves though a notch in the ring plate, e.g., notch  508 . When the device is assembled, seals  306  and  308  seal the outside of chambers  360 ,  362 ,  364  and  366 . 
     One may want to change parts if face  368  ( FIG. 5 ) becomes damaged or worn. Therefore, the rotor may be designed to accept a replacement face on replacement  378  ( FIG. 17 ). 
     Front and rear ring plates  396  and  398  cover rotor arms  312 ,  314 ,  316  and  318 , chambers  360 ,  362 ,  364  and  366  and rockers  370 ,  372 ,  374  and  376 . See  FIG. 3 . The ring plates may be formed of ductile iron. Front ring plate  396  has four cutouts  484 ,  486 ,  488  and  490  ( FIG. 3 ). Each aligns with one of the bores  350 ,  352 ,  354  or  356  in rotor arm  312 ,  314 ,  316  and  318  ( FIGS. 6   a  and  6   b ). Rear ring plate  398  also has four cutouts  496 ,  498 ,  500  and  502  ( FIG. 3 ). Each aligns with a cutout on the front ring plate. 
     The rockers&#39; pivot pins such as pin  380  may extend into bores such as bores  394  on front ring plate  396  ( FIG. 3 ) and to corresponding bores (not numbered) on rear ring plate  398 . The ring plates may be formed of ductile iron. The pivot pins also could extend into recesses, which extend into but not through the ring plates. See also similar but recessed bores in alternative ring plates  492  and  494  in  FIGS. 15 and 16 . Bores  388 ,  390  and,  392  and the other unnumbered bores on the ring plate can be used for bolting front rotor ring plate  396  to rotor  310 . Corresponding bolts or other fasteners attach rear ring plate  398  to the rotor. The fasteners (not shown) attach to threaded bores  386  ( FIGS. 3 ,  4 ,  5 ,  6   a  and  6   b ) on rotor arms  312 ,  314 ,  316  and  318 . The bores&#39; positions used to attach the ring plates can vary.  FIG. 3  shows two additional bores for those that are numbered. Thus, each ring plate could be attached by twelve fasteners (four sets of three fasteners) to the rotor. 
     For positioning by hand, dowels may be used to align appropriate holes, e.g., hole  388  in ring plates  396  or  398 , with the appropriate bore  386 . Automated assembly may use different techniques. 
     The following discussion uses rocker  376  as an example for all rockers  370 ,  372 ,  374  and  376 . Rocker  376  may include two spaced-apart pin bosses  410  and  412  ( FIG. 7 ), which may be integrally formed as part of the rocker. Rocker rod pin  414 , which may be  4140  steel, extends through bores  416  in pin boss  410  (only one visible in  FIG. 7 ). The rocker rod pin also extends through the upper bore  420  of link  418  ( FIGS. 3 and 7 ).  FIG. 3  also shows the link&#39;s lower bore  422 . The link also may be 4140 steel. 
     Rockers  370 ,  372 ,  374  and  376  pivot about their respective pivot pins, e.g., pin  380  in rocker  376  ( FIG. 5 ). Each rocker pivots between an outside position, which is close to inside surface  204  of housing body  202 , to an inside position away from the inside surface and back to the outside position. Thus, in  FIG. 5 , rockers  370  and  374  are shown in the inside positions, and rockers  372  and  376  are shown in the outside positions. These positions are temporary because the rockers pivot in and out as described below. 
     Pivoting of each rocker  370 ,  372 ,  374  and  376  rotates a corresponding outer crankshaft  430 ,  432 ,  434  and  436  ( 7  and  8 ). Likewise, rotating an outer crankshaft pivots its corresponding rocker. The outer crankshafts may be made of  4140  steel. Though each could be formed of one piece,  FIGS. 7 and 8  show the following parts comprising each outer crankshaft assembly. Crankshaft  436  includes front and rear wheels  440  and  442  ( FIGS. 7 and 8 ). The front wheel includes rearward facing journal  444  that has a tang  446  at its end. The tang seats in tang receiver  448  in rear crank wheel  442  ( FIG. 8 ). Front spur gear  450  includes a tang  452  that seats in tang receiving opening  454  in front wheel  440 , and rear spur gear  456  also includes a tang  458  received within its tang receiving opening (not visible in  FIG. 8 ) in rear crank wheel  442 . 
     Bolts  460  and  462  ( FIG. 5  (only two numbered) and  FIGS. 6   a  and  6   b ) or other fasteners extend through the bolt holes  464  and  466  in front spur gear  450  and through aligned holes  468  and  470  in front crank wheel  440 , through aligned holes  472  and  474  in rear crank wheel  442  and into hole  476  and  478  in rear spur gear  456 . Threads for engaging the bolts inside the rear spur gear are not visible. Consequently, the bolts secure the front spur gear, the front and rear crank assemblies and the rear spur gear together. 
     Front and rear wheels  440  and  442  of each outer crankshaft, e.g. crankshaft  436 , may have an oil groove  480  and  482  ( FIGS. 7 and 8 ) for lubricating the wheels. The oil grooves may receive lubricant from oil feed  338  ( FIG. 11 ). The oil feed may be angled for ease of machining. Alternatively, the oil feed could be straight by drilling it after drilling through arm plates  340  and  344 . 
     Pressure from gases caused by ignition of fuel in the combustion chamber associated with rocker  376  pivots the rocker inward (i.e., right side moves downward in  FIG. 7 ). Accordingly, the rocker drives link  418  against journal  444  of outer crankshaft  436 , which rotates the crankshaft. The parts are dimensioned such that when the rocker reaches in innermost position, the crankshaft journal is at or near its bottom position. Continued rotation of the journal drives the rocker outward. If the rocker is in position other than being pushed by gas expansion and depending on the position of the rocker in its cycle, the crankshaft pulls or pushes the rocker. 
     Main crankshaft  610  is discussed before discussing the outer crankshafts&#39; operation. The main crankshaft ( FIGS. 2 ,  3 ,  5  and  12 ), which may be  4130  steel, provides power from the engine to power a vehicle or produce other useful work. The main crankshaft may be one piece, but the different diameter portions are described as if they were separate parts attached together. The main crankshaft may include a section  616  ( FIG. 3 ), which has a larger diameter than intermediate diameter portions  614 . Oil grooves  650  and  652  ( FIG. 12 ) at the ends of the larger diameter section carries oil for lubrication. The main crankshaft also includes smaller diameter flanges  612  and  618  at the crankshaft&#39;s end. In addition, sleeve  616  includes a longitudinal keyway  632  ( FIG. 12 ). Although  FIG. 12  shows only one keyway, there can be more than one. 
     The longitudinal center of main crankshaft  610  may be hollow to transfer oil to outside the crankshaft and from one oil hole to another. For example, one or more oil distribution channels  640  ( FIG. 12 ) may extend along the center, larger-diameter section  616  and connect with oil grooves  650  and  652 . Likewise, one or more additional circumferential oil troughs  642  and  644  may extend around the outside of the main crankshaft&#39;s smaller diameter flanges  612  and  618 . Oil feeds  628  and  630  may carry lubricant to the oil troughs. Flanges  612  and  618  may have keyways  634  and  636 . The ends of the flanges form bolt holes  638 , only one of which is visible in  FIG. 12 . 
     Thrust ring  540 , which may be bronze, mounts in thrust ring cavity  542  in rotor  310  ( FIGS. 6   a ,  6   b  and  11 ), and a corresponding thrust ring mounts on the other side of the rotor. Each thrust ring has a bore  544 . Main crankshaft  610  may mount to the rotor as follows. It may be positioned inside cavity  542 . The thrust rings are slid over the main crankshaft, and key  546  from each thrust ring engages keyway  640  of sleeve  616 . 
     Main crankshaft  610  extends through ring gears  620  and  622  and ring plates  396  and  398 . The ring gears may be 4140 steel. The main crankshaft mounts in bores (only bore  510  is visible in  FIGS. 6   a ,  6   b  and  11 ) in the center of arm plates  340  and  342 . The ring gears may be fixed against the insides of front plate  230  and rear plate  232  ( FIGS. 1 and 2 ). For example, the ring gears may be fixed to mounting plate  662  and bolts  660  may secure the ring gears and mounting plate to the front and rear plates. The ring gears also may be fixed to other structure. 
     The teeth of front spur gear  450  and rear spur gear  456 , which are associated with outer crankshaft  436  and rocker  376 , engage the teeth on ring gears  620  and  622 . Likewise, other spur gears on the other outer crankshafts, e.g.,  432 ,  434 ,  436 , associated with the other rockers also engage the teeth on the front or rear ring gear. Because the ring gears are stationary, spur gear rotation causes the spur gears to revolve around the ring gears. The connection of the outer crankshafts including their spur gears to rotor  310  causes the rotor to rotate about the rotor&#39;s axis of rotation. That axis coincides with the main crankshaft&#39;s axis of rotation. 
     In the figures, the spur gears travel around the outside of the ring gear. The ring gear could be a planetary gear with internal teeth so that the spur gears would travel around the inside of such a gear. Further, although the drawings show spur gears engaging a ring gear, the gears could be replaced with other devices such as belts, chain drives and friction drives capable of driving or being driven through their interaction. 
     The ratio of the number of spur gear teeth to ring gear teeth can be modified. Doing so changes the angular distance that rotor  310  travels for each rotation of the spur gears, e.g., gears  450  and  456 . 
     Flanges  612  and  618  of main crankshaft  610  may extend through bores  244  and  246  in front and rear plates  230  and  232  ( FIG. 2 ). Having only one flange protrude from housing  200  may be acceptable, however. The crankshaft flanges may extend through respective openings  252  and  254  of crankshaft collars  248  and  250 . Fasteners (not shown) through openings  256  in front crankshaft collar  248  engage bores  258  in front plate  230 , and corresponding fasteners secure the rear collar  250  to the rear plate. Those parts are unnumbered. See also  FIG. 1 . Each collar may have seals (not shown) around the inside of openings  252  and  254 . A timing mark mount hole  260  ( FIG. 2 ) also may be provided. 
     Front and rear plates  230  and  232  may include oil ring seal groove  238  (only shown on plate  232  in  FIG. 2 ). Corresponding ring seals (only seal  532  is visible in  FIG. 2  and shown in  FIG. 18 ) seat in the ring seal grooves to create a seal between the front and rear rotor ring plates  396  and  398  and the insides of front and rear housing plates  230  and  232  when those plates attach to housing body  202 . The ring plate seals may include an annular shoulder  530 , which faces and is contact with the ring plates. The ring plate seals may be cast iron, silicon graphite, carbon fiber or other appropriate material. Springs (not shown) may bias the ring plate seals toward the front and rear ring plates. 
     Ring plate seals  532  remain stationary with respect to housing plates  230  and  232  during rotor rotation. Thus, the rotor&#39;s ring plates  396  and  398  slide on the ring plate seal. The ring plate seals have an rim shoulder  534  as  FIG. 18  shows. Gaskets (not shown) also may seal plates  230  and  232  to the housing body. Other devices or systems may be provided to prevent galvanic corrosion due to any dissimilar metals being in contact with each other. 
     The ring plates could have different designs, and  FIGS. 15 and 16  show two alternative designs for ring plates  492  and  494 . Outer face  580  includes boss  582 . The boss fits into a corresponding indentation on the housing front or rear plate that would be modified from end plates  230  or  232  in  FIG. 2 . Openings such as openings  584 ,  586  and  588  may serve several functions. Openings  584  and  586  and corresponding holes in ring plate  494  are for fasteners (not shown) for attaching the ring plates to the rotor. Openings  590  and  592  ( FIG. 16 ) are for spur gear clearance and support. One opening in each quadrant may mount a pivot pin for the rotor&#39;s rockers. Instead of the cutout extending completely through the ring plates as cutout  484 ,  486 ,  488  and  490  extend in  FIG. 3 , the cutouts in  FIGS. 15 and 16  are recesses in the inside wall of the ring plate. See, for example, recess  590  in  FIG. 16 . Spur gears  594  ( FIG. 20 ), mount in each recess. Bore  588  and  592  ( FIGS. 15 and 16 ) extends through the ring plate and receive hub  596  of the corresponding spur gear. A shaft would extend through the bore to connect a spur gear to the wheel of the outer crankshaft. Openings (not shown) also could be provided adjacent the spur gears for spraying lubrication onto the spur gears. 
     For the engine to operate, controlled amounts of air and fuel are injected through intake port  514  ( FIGS. 9 and 10 ) as rocker  374  ( FIG. 5 ) is pivoting inward. Electronic control may vary the amount of air and fuel or the air-fuel ratio. A turbocharger or supercharger could increase the volume of air (oxygen) through the intake port. As the spur gear on outer crankshaft  434  revolves about front ring gear  620  (and a corresponding spur gear revolves about rear ring gear  622 ), the outer crankshaft rotates. The outer crankshaft&#39;s connection through a link to rocker  374  pivots the rocker inward. The inward pivoting causes a pressure decrease in chamber  366  (marked “input” chamber in  FIG. 5 ). 
     After chamber  366  receives a predetermined amount of air and fuel, rotor  310  rotation carries chamber  366  past intake port  514 . Further rotation of the rotor causes outer crankshaft  434  to begin pivoting rocker  374  outward. Because the drawings are not animated and the components remain stationary, consider that chamber  366  has moved to the position where chamber  360  had been in the drawings and that the reference numerals for the parts that had been there now are used. As rocker (now  376 ) pivots outward, the decrease in volume in chamber  360  causes a corresponding pressure increase (compression) to the air-fuel mixture in the chamber above the rocker and in any recess  524  for a spark plug (discussed below). 
     The top surface of the rockers, e.g., rocker  376 , may be coated. The top surface has central combustion region  402  ( FIG. 7 ) surrounded by squish zone  408 . In a piston engine, a squish zone is a narrow section of a combustion chamber in which the air-fuel mixture is more compressed than in the rest of the chamber. A squish zone helps direct the flow of the fresh air-fuel mixture and to improve scavenging, i.e., pushing exhausted gas out of the cylinder. Here, squish zone  408  is a surface area raised from surface  402  and matches the inside surface  204  ( FIGS. 9 and 10 ) of housing body  202 . This raised surface creates higher pressures around the extended edges of combustion surface  402 . 
     Squish zone  408  may create turbulence by compressing the air-fuel mixture in the zone as the mixture reaches full compression over central combustion region  402 . This may allow more complete burning of the gaseous mixture to decrease emissions. The squish zone also may improve exhausting of the remaining burnt gases. The surface of the squish zone may be 0.010 in. to 0.080 in. (0.25 mm to 2 mm) (metric equivalents are approximations) above combustion surface  402  with 0.020 in. to 0.060 in. (0.5 mm to 1.5 mm) possibly preferred. 
     The hot end of spark plug  520  ( FIG. 4 ) in mount  522  extends toward chamber  360  such that spark from the spark plug can ignite the fuel. High-pressure, direct injectors may be installed into housing  202  in close proximity to the spark plug for gasoline direct injection. The hot end of the spark plug may terminate in a recess  524  in inner wall  204  of housing body  202  ( FIG. 9 ). The recess is shown as cylindrical, but could be sized and shaped to improve combustion. The drawing show a single spark plug, but having two or more plugs for each combustion chamber may improve operation. In addition, a spark plug is shown in the drawings, but the rotary motor could work using the diesel cycle at higher pressures and without a spark plug. Those higher pressures may require different materials or different dimensions for the rotary engine&#39;s components. 
     The spark plug fires at a predetermined time for proper engine timing The ignition of the fuel in the presence of air in chamber  360  causes a substantial increase in pressure in the chamber. That pressure applies a force on rocker  376  to force the rocker inward. As rotor  310  continues rotating, what had been chamber  360  rotates into the position of chamber  362  in  FIG. 5 . This is a movement from the compression of the chamber to the power from the chamber. Thus, rocker  370  pivots to its inward position. ( FIG. 5 ) 
     Through the connection of outer crankshaft tang  436  with tang receiver  448 , the inward movement rotates outer crankshaft  442 . As a result, spur gears  450  and  456  rotate and travel along the outside of ring gears  620  and  622  ( FIGS. 3 and 5 ). This, in turn, causes rotor  310  to rotate. 
     Continued rotation of rotor  310  positions the chamber in question to the position of chamber  364  in  FIG. 5 . During this rotor rotation, the spur gears associated with the rocker (now rocker  372 ) act on the link between the outer crankshaft and the rocker to pivot the rocker outward. The outward pivoting pushes exhaust gases through exhaust port  516  ( FIGS. 2 ,  9  and  10 ). The cycle then repeats itself. 
     During each revolution of rotor  310 , each of the four chambers sequence through four cycles: intake, compression, combustion and exhaust. By choosing the offset pivot of the rocker link, e.g., link  418  relative to its outer crankshaft  436  and to its rocker  376  ( FIG. 7 ) and the position of its pivot pin  380 , the engine can modify the timing of the intake, compression, combustion and exhaust cycles. Because the rocker&#39;s pivot is stationary, the pivot also may create an arc-shaped offset angle. For example, the rockers can have longer power and intake cycles than their compression and exhaust cycles. Those cycles may be as follows: intake=100°, compression=80°, combustion=100° and exhaust=80°. This overlap could allow each combustion cycle to fire 20° before the previous chamber has finished its power cycle. This overlap function may allow smoother transitions between power cycles. 
     In addition, the intake and exhaust ports  514  and  516  ( FIGS. 9 and 10 ) may overlap so that new air and fuel enter the combustion chamber through the intake port as it opens and before the exhaust port is completely closed-off. This may allow a small rush of new air-fuel mixture to push out the remaining exhaust gases drawing in a completely new charge of fuel and air. The intake/exhaust overlap may be from 4° to 24°, and preferably may be 8°. 
     Note that only the outer crankshaft positioned with the rocker moving from combustion-caused expansion receives power directly from that combustion-caused pressure acting on the rocker. Through rotation of that outer crankshaft&#39;s spur gear acting on ring gears  620  and  622 , rotor  310  rotates. At the same time, continued rotation of the rotor causes the spur gears for the other three outer crankshafts to rotate, which, in turn pivots the rocker associated with the crankshaft to pivot in or out. However, as each spur gear moves to the power/combustion position where the air-fuel mixture ignites, expanding gases drive the rotor inward. Consequently, that set of spur gears become the driving gears, and the other spur gears become driven gears. 
     The rear face of front ring plate  396  and the front face of rear ring plate  398  are against the respective sides of rotor  310 . Each side of the rotor may have a sealing groove  530  that may run along the periphery of the arms. See  FIGS. 5 ,  6   a  and  6   b . Only groove  530  is visible in the drawings. Rotor seal cord may be installed in the sealing grooves on both sides of rotor to seal the arms to ring plates  396  and  398 . 
     Main crankshaft  610  extends through collar  248  ( FIG. 1 ). If the rotary engine is used on a vehicle, the main crankshaft connects to the rest of the vehicle&#39;s drive train, e.g., transmission, clutch or other component. For non-vehicle uses for machines such as pumps and compressors, the crankshaft connects to the driven device. The main crankshaft also could be driven if the device is used as a compressor or pump. (See  FIG. 19 ). The main crankshaft also may extend out either side or both sides of the housing. 
     Components may have channels and openings for coolant and lubricant. These are not explained in detail and may vary with different engine sizes and designs. However, see openings  346  and  348  ( FIGS. 6   a ,  6   b  and  11 ), which could be used for cooling or lubrication. The arms also may have oil jets, e.g., jet  338  ( FIG. 11 ) for providing lubrication in the chambers. These oil jets may be pressure or movement activated, allowing oil to pass only when desired. Other physically activated (pressure or movement) oil jets may be placed on various component parts, such as the front and rear plates  230  and  232  ( FIG. 2 ) for controlled oiling of moving parts. Components and parts may have bushings or bearings (not shown) where needed for reducing friction, metal to metal contact protection, or holding desired tolerance specifications. Oil vacuum ports on the front and rear plates  230  and  232  ( FIG. 2 ) may be placed at the lowest available gravitational oil collection area, depending on the physical mounting position of the engine, to extract oil away from moving parts. Parts also may have cutouts to decrease weight or provide better heat dissipation. 
       FIG. 4  shows some additional parts of the rotary engine in a vehicle. The air intake system  110  may include air filter  112  on throttle body  114 , which connects to intake manifold  116 . Air from the intake system flows into intake chamber  366  ( FIG. 5 ). Fuel injector  126  also is positioned near the intake chamber. The engine may be designed to burn different fuels, e.g., gasoline, ethanol, CNG, LNG, propane, or hydrogen. The fuel injector of such an engine could have separate outlets  128  and  130  for different fuels. Exhaust from chamber  364  passes into exhaust header  118  and into the remainder of the exhaust system. Starter motor  120  and alternator  122  and engine electronics in an electronic control unit  124  also attach to housing  200 . 
     The size of the engine compartment and the position of the rotary engine in the engine compartment may affect the various components&#39; locations insofar as they must fit in the compartment and may need to be accessible for service. 
     Belts or other connectors (not shown) may drive the alternator and other devices from engine power. 
       FIG. 13  shows a two-chambered rotor for a rotary engine. Rotor  550  rotates twice for each power engine power stroke. The rotor has two arms  552  and  554  that may be shaped as shown in  FIG. 13 . The arms form two opposite chambers  556  and  558 . Rockers  560  and  562  mount on respective pins  564  and  566 . Outer crankshafts (now shown) connect to rockers through linkage similar to that shown in  FIG. 7 . Each crankshaft may have spur gears (now shown) at the outer crankshaft end that protrude through bores  568  and  570  from the rotor. A main crankshaft (not shown) protrudes from center bore  572 . Stationary ring gears (not shown) mount to stationary housing structure. 
     In one position in  FIG. 13 , the air-fuel mixture is injected or otherwise enters one of the chambers, e.g., chamber  556 . As rotor  550  rotates, rocker  560  pivots outward to compress the air-fuel mixture until, at or close to full compression, a spark ignites the air and fuel. The rotor rotates without exhausting the exhaust gases until the rotor returns to its initial position, i.e., where chamber  556  is in  FIG. 13 . Valves (not shown) control intake and exhaust from chambers  556  and  558 . One or more valves open to allow the airfuel mixture to enter chamber  556 , and then one or more different valves open to allow the exhaust gases to enter the exhaust system. 
     The rotary engine that has been described is a four-stroke engine, intake, compression, combustion and exhaust. In a four-stroke piston engine, those strokes occur every two rotations or the crankshaft. Two-stroke piston engines complete a cycle in two movements of the piston, in and out. The rotary engine could be modified into a two-stroke engine. Two- and four-stroke designs have advantages and drawbacks relative to each other. 
     A typical use of internal combustion engines is in vehicles. Just as piston engines come in different sizes, compressions, power rating and other factors for different vehicles, the rotary engine&#39;s specifications can vary. Insofar as the rotary engine powers generators, pumps, machinery or other devices, the engine may have different designs. Some might require higher speed but less low-speed torque. Other application may require high torque at low speed. Some application may require constant output over long periods. Adjusting the combustion chamber volume, the size and pivoting angle of the rockers and other factor of the rotary engine may be modified to satisfy an engine&#39;s requirements. 
     At least two ways allow matching output power to power needs. The first is to have larger combustion chambers with larger rockers. Increasing the diameter of rotor  310  may allow the rockers to pivot through a larger angle to increase displacement. Likewise, increasing the width of the rotor also increases the displacement of each chamber. Optimizing performance may require balancing the effect of increasing the rotor&#39;s diameter and width. For example, increasing dimensions weight of all components and may affect other engine components or engine symmetry. 
     Stacking two or more power modules along the main crankshaft also could combine the modules&#39; power output. In addition, combinations of different sized power modules can be assembled into one unit. 
       FIG. 14  shows a duel unit  700  comprising a front unit  702  and rear unit  704 . The front unit is bounded by front plate  706  and center plate  710 , and the rear unit is bounded by rear plate  708  and center plate  710 . In  FIG. 14 , the locations where combustion occurs are on the same side of the housing, but they could mount 180° apart. Likewise, with more rotors for one engine, the location where combustion occurs could be spaced evenly around each housing, e.g., 120° apart for three rotors and 90° for four rotors. 
     Though the configuration just described are internal combustion engines, the device with modifications can become a compressor. Compressor  800  ( FIG. 19 ) comprises housing body  802 . Compressors may be free-standing. Therefore, the compressor may include base  804 . The housing body has a cylindrical opening  806  in which a rotor (not shown) mounts for rotation. Front and rear housing plates (not shown; similar to pates  230  and  232  in  FIG. 2 ) cover the rotor and cylindrical opening. Seals  810  and  812  may seal the housing plates to the housing body, and fasteners (not shown) extending through openings in the housing plates may attach to bores  808  in the housing body. The main crankshaft extends through the housing plates and connect to a separate motor or engine. When the device is used as a compressor, the main crankshaft is driven instead of providing the motive force. 
     Housing body  802  includes one or more inlets  820  and  824  and one or more outlets  826  and  828  ( FIG. 19 ). These inlets and outlets could be used for high pressures such as for hydraulic pressurization. Valves may be provided for any inlets or outlets, and their construction and operation may depend on the fluid volume and pressure. Various bore such as bores  830 ,  832 ,  836  and  838  may be provided for fastening related devices, such as inlets and outlets for lubrication. 
     Rotor rotation causes the rockers to pivot in an out. The inlets are positioned to receive air, other gas or liquid (“fluid”) either from the atmosphere in the case of air or from a source of fluid. The fluid flows into one of the rotor chambers as the rocker pivots inward to lower the pressure. When the rotor rotates away from the inlet, the rocker pivots outward to compress the fluid and force it through an outlet. With a four-chambered rotor, the rotor rotates to another inlet, draws fluid into the chamber and then compresses the fluid as the rotor moves adjacent another outlet. 
     Four strokes are not necessary. Thus, pressurized fluid can flow out an outlet at all compression strokes (pivoting outward of the rocker). Accordingly, the rotor could have two, four, six or more chambers with a corresponding number of rockers and outer crankshafts subject to space limitations. 
       FIG. 21  illustrates a rotor with eight chambers, which may be particularly useful as a heavy-duty diesel unit. Because  FIG. 11  has reference numerals for its components, and  FIG. 21  shows components with related functions, the description of FIG.  21 &#39;s parts is abbreviated. 
     Rotor  910  has eight arms  912 ,  914 ,  916 ,  918 ,  920 ,  922 ,  924  and  926 . Adjacent arms form eight chambers such as chamber  930  between arms  914  and  916  and chamber  923  between arms  916  and  918 . The inner cylindrical wall (not shown) of the housing receiving rotor  910  forms the outside of each chamber. Rocker  934  mounts near the distal end of arm  916  and pivots in and out of chamber  930 . It is shown in in  FIG. 21 . Similarly, rocker  936  mounts near the distal end of arm  918  and pivots in and out of chamber  932 .  FIG. 21  shows its outward position. the rotor also mounts six other rockers, which are not numbered. 
     The rotor is formed of front plate  940  and a corresponding rear plate, which is not visible in  FIG. 21 . Bores such as bores  942  and  944  extend through the rotor&#39;s front plate, and corresponding and aligned bores (not shown) extend through the rear plate. Properly sized wheels mount in the bores, and spur gears mount to the wheels and extend out of the bores.  FIG. 21  shows neither the wheels nor the spur gears. The drawing also does not show a ring gear mounted on a main crankshaft extending through central bore  946 . The spur gears engage the ring gear and rotate as the rotor rotates about its axis. Linkages between the wheels and the rockers cause the rockers to pivot in and out of their respective chambers as the rotor rotates. However, when fuel ignites in the chamber that is then the power chamber, force from the expanding gas on the rocker rotates the wheels and spur gear. That rotation acts on the ring gear to rotate the rotor. 
     The rotor may have additional bores such as bores  950  and  952  to decrease weight. The bores also may carry lubricant. 
     The outside of each arm that contacts or is close to contact with the cylindrical wall of the housing may have two grooves, e.g., grooves  958  and  960 , which receive seals (not shown). Other seals for sealing the chambers and the rotor itself are not shown. 
     In the eight-chamber version, the air-fuel mixture ignites simultaneously in two chambers on opposite sides of the housing. Thus, during each rotor rotation, each chamber completes eight cycles (intake, compression, power, exhaust, intake, compression, power, and exhaust). Engines with  12 ,  16  or more chambers per rotor are contemplated. They may be particularly useful for large and heavy equipment such as earth movers, mining dump trucks, and cranes. 
       FIG. 22  is a perspective view of a ring seal assembly  1000  for use with the ring plate  492  shown in  FIG. 15 . Ring seal assembly  1000  includes a first ring seal pack  1002  and a second ring seal pack  1004 . Each seal pack  1002  and  1004  includes a first resilient member  1006  abutting a first ring seal  1008 , a second resilient member (not shown) positioned between first ring seal  1008  and a second ring seal  1010 . Second ring seal  1010  mates with an outer surface of ring plate  492 . In the exemplary embodiment, second ring seal  1010  of first seal pack  1002  is configured to mate with mating surface  580  of ring seal  492 , and second ring seal  1010  of second seal pack  1004  is configured to mate with mating surface  580  of ring plate  492 . In the exemplary embodiment, resilient member  1006  is an O-ring. In one embodiment, the second resilient member is configured to include a channel for receiving oil. Such a channel enables seal assembly to have a compression that is pneumatically and/or hydraulically controlled using a control assembly including, but not limited to, an oil pump. The use of resilient member  1006  enables ring seal assembly to function as a compression seal. 
       FIG. 23  is a top perspective view of a crossover seal  1100  for use with rotor  310  shown in  FIG. 5 ,  FIG. 24  is a bottom perspective view of crossover seal  1100 , and  FIG. 25  is an exploded view of crossover seal  1100 . Crossover seal  1100  includes a first seal  1102  and a second seal  1104 . Each seal  1102  and  1104  has a first circumferential edge  1106  and a second circumferential edge  1108 . Edges  1106  and  1108  are configured to mate with ring seal assembly  1000  to substantially seal combustion chambers. Each seal  1102  and  1104  includes a recess  1110  for retaining a spring  1112 . 
     Crossover seal  1100  is configured to seat within the space between extensions  322  and  324 . In operation, in the exemplary embodiment, first seal  1102  is forced in a first direction and second seal  1104  is forced in a second direction opposite the first direction. Spring  1112  located in a seal spring cavity of rotor  310  and recess  1110  forces seals away from one another in a lateral direction. In this implementation, as edges  1106  and  1108  wear and recede, spring  1112  forces seals  1102  and  1104  towards ring seal assembly  1000  to maintain a constant seal within combustion chambers to maintain a constant pressure. Additionally, a top surface  114  of seals  1102  and  1104  contacts and seals against the inner diameter of sleeve  1300  or directly against the inner diameter of housing  1200 . As edges  1114  wear and recede, spring  1112  and centrifugal force seal  1102  and  1104  towards the sleeve  1300  or housing  1200  inner diameter to maintain a constant seal and/or pressure within combustion chambers. In the exemplary embodiment, a crossover seal width is larger in arc length than the diameter of the spark plug and/or injector ports in sleeve  1300  and/or housing  1200  to maintain a constant pressure and avoid leakage through such ports. The sealing by crossover seal  1100  creates a sealing force that substantially prevents chamber crossover leak and chamber cross-talk and substantially prevents crankcase pressurization. 
     In another implementation, a fluid or gas pressurization is maintained in the seal spring cavity to force first and second seals  1102  and  1104  laterally outward opposing each other and radially outward together. Utilizing fluid or gas pressurization enables the engine to maintain a regulated constant sealing force or an RPM linked sealing force. A fluid pressurization system also enables a pump oiling system to provide lubrication to crossover seal  1100  as well as potentially cool seal  1100  from an underside. 
       FIG. 26  is an exploded view of an exemplary housing body  1200  and sleeve  1300 , such as the housing body  200  shown in  FIG. 2 . 
     Sleeve  1300  is configured to act as an intermediary part between housing  1200  and power module  300 . Sleeve  1300  is designed to be scalable from 50 milliliters to over 200 liters through an increase either in chamber (and piston) size or a stacking of power modules or both. Sleeve  1300  is fabricated to interface statically, via a tight tolerance press or clamp, with an inner surface  1202  of housing  1200  around an outer surface perimeter  1302  of sleeve  1300  along all or a part of an axial length of sleeve  1300 . In the exemplary embodiment, the sleeve includes tabs or flats  1304  that mate with housing recesses or flats  1204 . Similar to housing  1200 , sleeve  1300  includes an inlet  1306 , an outlet  1308 , at least one entry point  1310 , and an access point (not shown). Sleeve  1300  interfaces statically with main unit  1200  around housing inlet  1206 , housing outlet  1208 , and at least one entry point  1210  to provide a substantially leak-free flow path connection (e.g., not a pass-through) with inlet  1306 , outlet  1308 , and at least one entry point  1310  respectively. 
     Sleeve  1300  can have a varied wall thickness depending on design demands and sizing. In one embodiment, the sleeve wall thickness ranges from 0.1 inches to 0.75+ inches. In the exemplary embodiment, sleeve 1300 wall thickness is between 0.15 inches and 0.5 inches. Alternatively, sleeve  16  can have any wall thickness that facilitates sealing as described herein. Sleeve  16  can utilize housing  1200  as a mechanical support for backup on outer diameter  1200  for increased hoop stress and mechanical integrity. Additionally, sleeve  16  can function as a heat conductor to move heat away from combustion chambers and into housing  1200 . Sleeve  1300  provides improved serviceability by allowing a worn or contaminant gouged power module crossover seal interface surface to be easily replaced without requiring replacement of an entire housing. 
     The use of housing  1200  and sleeve  1300  enables the material not in direct contact with power module crossover seals  1100 , (i.e., housing  1200 ), to be made from a lighter weight and better heat conducting material since it does not receive any wear from seals  1100 . Additionally, the use of sleeve  1300  enables the surface contacting the power module&#39;s crossover seals  1100  to be made from a heavier, stronger, longer wearing, and lower coefficient of friction material to endure the wear. As such, sleeve  1300  interfaces with power module  300  dynamically through crossover seals  300  to provide a seating-in, sealing, and wear surface for crossover seals  1100 . Sleeve  1300  also forms an outward most chamber sliding surface area for pistons in power module  300 . 
     The use of sleeve  1300  enables a flow path through housing inlet  1206  and housing outlet  1208  to be varied in cross-sectional area through sleeve changes. For example, intake  1306  having a smaller cross-section shape than housing inlet  1206  enables intake  1306  to reduce the flow path through housing inlet  1206  to the cross-sectional size and/or shape of intake  1306 . As such, ports  1302 ,  1306 , and  1308  can change a flow path into and out of combustion chambers. Changing a cross-sectional area of a flow path is similar to changing a valve size, which affects a duration and final chamber charge and/or discharge. Such a variation is similar to a cam lobe height affecting lift and cam lobe rise angle affecting lift rate, which affects duration and flow rate in an engine. In one embodiment, a port “width”, defined as the maximum dimension parallel with the sleeve axis, and a port “length”, defined as the maximum dimension perpendicular to the sleeve axis and along the sleeve&#39;s inner surface circumference. In this embodiment, “width” is akin to a lift rate and “length” is akin to a duration. A square port geometry with a side parallel to crossover seal  300  would give immediate high flow, which would simulate a very high lift rate and would have a long duration. A square port geometry with a diagonal perpendicular or parallel to crossover seal  1100  (e.g., a diamond) would give linear gradual increase to a high flow, which would simulate a nominal lift rate and would have a very long duration. As shown in  FIG. 27 , oriented rectangles, circles, oriented ovals, oriented triangles, and virtually any geometry of port cross sectional shape can be implemented for a variety of engine flow and charged/discharged chamber volumes for a given power module RPM. 
     In one embodiment, sleeve  1300  enables a flow path entry or exit angle through housing inlet  1206  and housing outlet  1208  to be varied through sleeve changes. As such, having a housing inlet  1206  and/or housing outlet  1208  centerline non-continuous with that of sleeve intake  1306  and sleeve exhaust  1308  affects flow path angles through housing inlet  1206  and housing outlet  1208  relative to a location of piston head  402 . As such, housing inlet  1206  and housing outlet  1208  flow path centerlines can be brought closer together or farther apart by use of sleeve  1300  thus controlling the overlap or time in which both housing inlet  1206  and housing outlet  1208  are both open to the same chamber. 
     In another embodiment, sleeve  1300  enables flow paths through housing inlet  1206  and housing outlet  1208  to be varied in axial neck-down or open-up geometries through sleeve changes. Flow through housing inlet  1206  and/or housing outlet  1208  going neck down in cross-sectional area from sleeve  1300  outer surface to sleeve  1300  inner surface will increase gas velocity flow through sleeve inlet  1306  and reduce the velocity through sleeve outlet  1308 . Alternatively, flow through housing inlet  1206  and/or housing outlet  1208  being spread out in cross sectional area going from sleeve  1300  outer surface to sleeve  1300  inner surface will decrease gas velocity flow through sleeve inlet  1306  and increase velocity flow through sleeve outlet  1308 . Such an embodiment supports controlling the duration or time in which a passing chamber sees housing inlet  1206  open or housing outlet  1208  open in degrees of power module rotation. As such, sleeve can be configured to affect duration, which can, in turn, affect charge and/or discharge velocity impacting engine torque and engine horsepower. 
     In another embodiment, sleeve  1300  enables housing inlet  1206  and housing outlet  1208  relative centerline locations, and hence timing, to be varied via the circumferential positioning of the intake  1306  and exhaust  1308  of assembly  1300 . Where the trailing edge of a chamber&#39;s crossover seal tangent line is relative to the trailing edge of exhaust port  1308  on sleeve&#39;s inner surface and where the leading edge of a chamber&#39;s crossover seal tangent line is relative to the leading edge of the intake  1306  on the sleeve&#39;s inner surface affects how long intake  1306  and exhaust  1308  are open together into a chamber. As such, entering intake  1306  can help push out escaping exhaust and escaping exhaust can help draw in entering intake air. 
     In yet another embodiment, sleeve  1300  enables the position of injector ports  1210 , for direct injection, to be varied relative to piston assembly bottom dead center (BDC) through sleeve changes. As such, sleeve  1300  can affect and/or change fuel timing by simply changing sleeve  1300  in housing  1200 . Likewise, sleeve  1300  enables the position of spark plug port  1210  to be varied relative to piston assembly top dead center (TDC) through sleeve changes. As such, sleeve  1300  can affect and/or change typical ignition timing. Additionally, port variations also enable the engine to run on different fuel types by utilizing a sleeve  1300  which can enable the engine to operate according to the requirements of a particular fuel type. 
     When detailed descriptions reference one or more drawing figures, the element being discussed is visible in that drawing. The element also may be visible in other figures. In addition, to avoid crowding of reference numerals, one drawing may not use a particular reference numeral where the same element is in another drawing with the reference numeral. 
     The description is illustrative and not limiting and is by way of example only. Although this application shows and describes examples, those having ordinary skill in the art will find it apparent that changes, modifications or alterations may be made. Many of the examples involve specific combinations of method acts or system elements, but those acts and those elements may be combined in other ways to accomplish the same objectives. With regard to flowcharts, additional and fewer steps may be taken, and the steps as shown may be combined or further refined to achieve the methods described. Acts, elements and features discussed only in connection with one embodiment are not intended to be excluded from a similar role in other embodiments. 
     “Plurality” means two or more. A “set” of items may include one or more of such items. The terms “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” and the like in the written description or the claims are open-ended, i.e., each means, “including but not limited to.” Only the transitional phrases “consisting of” and “consisting essentially of” are closed or semi-closed transitional phrases with respect to claims. The ordinal terms such as “first,” “second,” “third,” etc., in the claims to modify a claim element do not by themselves connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed. Instead, they are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term). Alternatives such as “or” include any combination of the listed items.