Positive displacement rotary system

A positive displacement rotary system may include a main rotor and a slotted rotor. The main rotor can include an interior cavity and a fixed vane (or blade) that is attached to the peripheral and side walls of that cavity. The slotted rotor is positioned within the main rotor interior and includes a slot for the main rotor blade. The main and slotted rotors rotate about parallel axes that are offset from one another. As the rotors turn, separate chambers are formed between the blade and an inter-rotor seal, with the inter-rotor seal located at or near a rolling contact between the outer surface of the slotted rotor and an inner perimeter wall of the main rotor cavity. The separate chambers contract and expand as the rotors rotate.

BACKGROUND

There are various known mechanisms for effecting positive displacement compression and/or expansion in engines, pumps, compressors and other devices. For example, reciprocating engines can employ pistons within cylinders to compress an air fuel mixture and to then output a mechanical force as that air fuel mixture is ignited and expands. Although reciprocating engines and other piston-based positive displacement systems are in wide use, such systems have numerous disadvantages. Piston-based systems can be quite complex and have numerous moving parts. The reciprocating nature of the piston motion can limit the speed at which an engine or other piston-based device can operate. Other disadvantages are well known.

Other types of positive displacement systems utilize rotary motion. For example, some rotary engines and pumps employ one or more vanes coupled to a rotor that turns within a cavity. The vanes maintain sliding contact with the cavity walls and define one or more chambers that vary in volume as the rotor turns. Such designs can have certain limitations, however. For example, maintaining an effective seal between the tip of a vane and a cavity wall can be problematic. Moreover, “chattering” can occur between vanes and the cavity wall. To overcome these and other problems, some designs may include a relatively large number of vanes or otherwise include features that increase complexity.

There remains a need for improved positive displacement rotary systems that can be utilized for internal combustion engines, compressors, pumps and other devices.

SUMMARY

In at least some embodiments, a positive displacement rotary system may include a main rotor and a slotted rotor. The main rotor can include an interior cavity and a fixed vane (or blade) that is attached to the peripheral and side walls of that cavity. The slotted rotor is positioned within the main rotor interior and includes a slot for the main rotor blade. The main and slotted rotors rotate about parallel axes that are offset from one another. As the rotors turn, separate chambers are formed between the blade and an inter-rotor seal, with the inter-rotor seal located at or near a rolling contact between the outer surface of the slotted rotor and an inner perimeter wall of the main rotor cavity. The separate chambers contract and expand as the rotors rotate.

Additional embodiments include systems that incorporate one or more main and slotted rotor pairs. Such systems include, but are not limited to, a rotary internal combustion engine, a fluid compressor, a pump, a fluid driven motor, a turbocharger, a combination internal combustion engine and motor/generator, and other systems. Additional embodiments include main and slotted rotor pairs that include additional blades and/or one or more additional slotted rotors.

DETAILED DESCRIPTION

FIG. 1Ais a front view of a combination rotary engine and motor/generator100according to some embodiments. For simplicity, engine and motor/generator100may be referred to simply as “engine100.”FIGS. 1B and 1Care side and rear views, respectively, of engine100. Engine100includes a housing101. A shaft102extends through a front face103and a rear face104of housing101. An air intake port105is located in front face103. An exhaust port106is located in rear face104.

For convenience, certain elements are not shown inFIGS. 1A-1C. For example, housing101could be divided into one or more sections that are secured together with bolts and sealed with one or more gaskets. Housing101may also contain one or more openings through which a wiring harness could extend so as to connect internal motor/generator elements to external loads, to a battery, etc. Housing101may also contain one or more openings through which cooling fluid lines may pass, openings through which a fuel line or other fuel conduit may carry fuel to a combustion chamber within housing101, etc. The selection of locations for these and other elements would be a matter of routine design choice for a person of ordinary skill in the art once such a person has been provided with the information disclosed herein and within the accompanying drawing figures.

FIG. 2is a cross-sectional view of engine100taken from the location indicated inFIG. 1A. The front portion of engine100includes an intake/compression main rotor201and an intake/compression slotted rotor202. The rear portion of engine100includes an expansion/exhaust main rotor203and an expansion/exhaust slotted rotor204. Each of main rotors201and203rotates about a main rotor axis AMR100. Each of slotted rotors202and204are attached to shaft102. Slotted rotors202and204and shaft102all rotate about a slotted rotor axis ASR100. As seen inFIG. 2, axes AMR100and ASR100are offset from one another.

Casing101includes internal components that can be configured to operate as a motor/generator. As used herein, “motor/generator” also includes combinations of components that can be configured for operation as a motor or as an alternator. Motor/generator windings and other components (e.g., permanent magnets in some embodiments) are located on the circumferences of main rotors201and203. In the embodiment of engine100, an armature208is attached to the outer periphery of main rotor201and rotates relative to a stator209attached to an inside wall of housing101. An armature210is similarly attached to the outer periphery of main rotor203and rotates relative to a stator211also attached to an inside wall of housing101. Armatures208and210and stators209and211can be used as a motor to rotate rotors201-204when starting engine100. After engine100has been started and a self-sustaining internal combustion cycle is underway, the rotation of armatures208and210within stators209and211can then be used to generate electrical power. Although each of rotors201and203includes an armature configured to rotate within a corresponding stator, other embodiments include engine and motor/generators in which only a single rotor includes an armature. For example, other embodiments could include engines in which only one main/slotted rotor pair includes motor/generator components.

Main rotor201is rotationally supported by bearings213and by bearings215. Main rotor203is rotationally supported by bearings217and by bearings219. Shaft102is rotationally supported by bearings221and by bearings223.

A front ring seal230is located on the front side of slotted rotor202. A similar rear ring seal231is located on the rear side of slotted rotor202. Seals230and231, which may be fixed relative to slotted rotor202and move relative to the inside surfaces of main rotor201, help to seal inter-rotor chambers formed between slotted rotor202and main rotor201. The operation of those chambers is discussed below in connection withFIGS. 6A-6F. A front ring seal232and a rear ring seal233are located in housing101. Ring seal233, in conjunction with seal230, helps to prevent leakage of compressed air being transferred to the expansion/exhaust side of engine100. Seal232, in conjunction with seal230, helps to ensure that the intake into a chamber between rotors201and202is from port105by, e.g., excluding intake from interior spaces of casing101that surround main rotor201. For certain embodiments in which the ring seals are exposed to temperatures between −40° C. (−40° F.) and 100° C. (212° F.), ring seal materials could include Buna-N, fluorosilicone, silicone, neoprene, TEFLON, VITON, rubber, nitrile, and the like. For embodiments in which ring seals may be exposed to temperatures above 100° C., ring seal materials could include graphite, carbon graphite, self-lubricating fluoride-metal composites such as fluoride-nichrome, high temperature materials coated with low friction diamond-like carbon, and the like.

A front ring seal236is located on the front side of slotted rotor204. A similar rear ring seal237is located on the rear side of slotted rotor204. Seals236and237, which may be fixed relative to slotted rotor204and move relative to the inside surfaces of main rotor203, help to seal inter-rotor chambers formed between slotted rotor204and main rotor203. The operation of those chambers is discussed below in connection withFIGS. 7A-7F. A front ring seal238and a rear ring seal239are located in housing101. Ring seal238, in conjunction with seal236, helps to prevent leakage of expanding air. Seal239, in conjunction with seal237, helps to ensure that exhaust gases are expelled through port106and not forced into spaces of casing101that surround main rotor203. Ring seals236-239can be formed from materials similar to those used to form ring seals230-233.

Fresh air is drawn into the intake/compression side of engine100through intake port105. Port105leads to an annular air supply manifold305, which manifold is described in more detail below. Fresh air drawn from manifold305is compressed between main rotor201and slotted rotor202, as is also discussed below, and then output through a compressed air channel242.

Channel242feeds into a combustion chamber243. Although not shown inFIG. 2, combustion chamber243also includes a fuel injector and an anti-backflow valve. In some embodiments that utilize gasoline as fuel for engine100, combustion chamber243may include a spark plug, glow plug or other ignition source. In certain other embodiments that utilize gasoline as a fuel, chamber243may include a fuel injector, and an ignition source can be included within an inter-rotor expansion chamber of rotors203and204. Such an ignition source could be incorporated into a portion of the outside surface of slotted rotor204. In some embodiments, engine100could be configured for operation using any of multiple fuel types and include multiple ignition sources. For example, a first ignition source could be included in chamber243and a second included within an inter-rotor expansion chamber. When using diesel fuel, kerosene, and various other fuel types, the first ignition source could be used and the second ignition source deactivated. When using gasoline or various other types of fuel, the first ignition source could be deactivated and the second ignition source used. In still other embodiments, chamber243may not include a fuel injector. For example, some embodiments could receive a fuel/air mixture from a carburetor located upstream from rotors201and202in intake105.

Returning toFIG. 2, compressed air and combustion products flow from chamber243through channel244and into an expansion inter-rotor chamber between main rotor203and slotted rotor204. After the expansion of the compressed air and combustion products forces rotation of rotors203and204(and thus of rotors201and202), the exhaust is scavenged and pushed out through exhaust port106.

FIG. 3Ais a cross-sectional view of engine100from the first location indicated inFIG. 2. The sectioning plane is positioned on the front side of slotted rotor202and the view ofFIG. 3Afaces toward the front of engine100. As partially seen inFIG. 3A, a blade301is fixed to the inner perimeter wall302and the inner front wall303of main rotor201. An inner circumferential opening304in main rotor201exposes an inner front face of housing101and several components located thereon. For example, seal232(discussed above) is visible. Also visible is an annular manifold305which connects to air intake105. A check valve (not shown) could be located in intake105.

FIG. 3Bis a cross-sectional view of engine100taken from the second location indicated inFIG. 2. The sectioning plane is positioned just to the rear of ring seal230and the view ofFIG. 3Bfaces toward the rear of engine100. Slotted rotor202includes an inlet port310that is connected to an inlet channel311. As explained in more detail in connection withFIGS. 4A-4C, only port310is exposed on the front side of rotor202. Channel311is only visible inFIG. 3Bbecause of the location of the cross-sectional plane.

Slotted rotor202further includes a slot312and a split-trunnion seal313. Seal313includes two halves313aand313bhaving shapes in the form of cylinder portions. Seal half313ais adjacent wall section315and seal half313bis adjacent wall section316. Walls315and316have cylindrical shapes corresponding to the outer faces of seal halves313aand313b. Blade301is located within a slot formed by the inner faces of halves313aand313b. As rotors201and202rotate, and as discussed below in connection withFIGS. 6A-6F, seal313rotates in an oscillatory manner about axis314while blade301slides in and out of seal313. Seal313prevents leakage of gases through slot312and around the interior tip of blade301. Seal313can be formed from materials similar to those used to form ring seals230-233.

Slotted rotor202also includes limited radial extension leaf seals321on the outer edge320at approximately 60° intervals. Leaf seals321, which help to prevent leakage of gases between portions of rotors201and202in rolling contact and create an inter-rotor seal, are further discussed below.

FIG. 3Cis a cross-sectional view of engine100taken from the third location indicated inFIG. 2. The sectioning plane is positioned just forward of ring seal231. The view ofFIG. 3Cfaces toward the front of engine100. Slotted rotor202further includes an outlet port325that is connected to an outlet channel326. As explained in more detail in connection withFIGS. 4A-4C, only port325is exposed on the rear side of rotor202. Channel326is only visible inFIG. 3Cbecause of the location of the cross-sectional plane.

FIG. 3Dis a cross-sectional view of engine100from the fourth location indicated inFIG. 2. The sectioning plane is positioned on the rear side of slotted rotor202and the view ofFIG. 3Dfaces toward the rear of engine100. Blade301is also fixed to an inner rear wall328of main rotor201. An inner circumferential opening329in main rotor201exposes an inner face of housing101and several components located thereon. For example, seal233(discussed above) is visible. Also visible is an arcuate manifold which connects to compressed air channel242(FIG. 2).

As seen inFIGS. 3E through 3H, the configuration of main rotor203and slotted rotor204are very similar to the configuration of main rotor201and slotted rotor202.FIG. 3Eis a cross-sectional view of engine100from the fifth location indicated inFIG. 2. The sectioning plane is positioned on the front side of slotted rotor204and the view ofFIG. 3Efaces toward the front of engine100. As partially seen inFIG. 3E, a blade334is fixed to an inner perimeter wall333and an inner front wall337of main rotor203. An inner circumferential opening335in main rotor201exposes an inner face of housing101and several components located thereon. For example, seal238(discussed above) is visible. Also visible is an arcuate manifold336which connects to channel244(FIG. 2). In some embodiments, arcuate manifold336extends over approximately 170° of the rotation of rotor204so as to minimize back pressure when a valve in chamber243admits the next charge of heated and compressed air into chamber243and an inter-rotor chamber of rotors203and204.

FIG. 3Fis a cross-sectional view of engine100taken from the sixth location indicated inFIG. 2. The sectioning plane is positioned just to the rear of ring seal236and the view ofFIG. 3Ffaces toward the rear of engine100. Slotted rotor204includes an inlet port340that is connected to an inlet channel341. As explained in more detail in connection withFIGS. 4A-4C, only port340is exposed on the front side of rotor204. Channel341is only visible inFIG. 3Fbecause of the location of the cross-sectional plane. Slotted rotor204further includes a slot342and a split-trunnion seal343. Seal343includes two halves343aand343bhaving shapes in the form of cylinder portions. Seal half343ais adjacent wall section345and seal half313bis adjacent wall section346. Walls345and346have cylindrical shapes corresponding to the outer faces of seal halves343aand343b. Blade334is located within a slot formed by the inner faces of halves343aand343b. As rotors202and204rotate, and as discussed below in connection withFIGS. 7A-7F, seal343rotates in an oscillatory manner about axis344while blade334slides in and out of seal343. Seal343prevents leakage of gases through slot342and around the tip of blade334. Slotted rotor204further includes leaf seals321on the outer edge350at approximately 60° intervals. Leaf seals321help to create an inter-rotor seal and prevent leakage of gases between portions of rotors203and204in rolling contact.

FIG. 3Ga cross-sectional view of engine100taken from the seventh location indicated inFIG. 2. The sectioning plane is positioned just forward of ring seal237. The view ofFIG. 3Gfaces toward the front of engine100. Slotted rotor204further includes an outlet port351that is connected to an outlet channel352. As explained in more detail in connection withFIGS. 4A-4C, only port351is exposed on the rear side of rotor204. Channel352is only visible inFIG. 3Gbecause of the location of the cross-sectional plane.

FIG. 3His a cross-sectional view of engine100from the eighth location indicated inFIG. 2. The sectioning plane is positioned on the rear side of slotted rotor204and the view ofFIG. 3Hfaces toward the rear of engine100. Blade334is also fixed to an inner rear wall355of main rotor203. An inner circumferential opening357in main rotor203exposes an inner face of housing101and several components located thereon. For example, seal239(discussed above) is visible. Also visible is an annular manifold356which connects to exhaust port106(FIG. 2).

FIGS. 4A through 4Cshow slotted rotor202mounted onto shaft102but removed from engine100. For convenience, rotor202is rotated approximately 30° from the positions shown inFIGS. 3B and 3Cso as to place slot312at top dead center.FIG. 4Ais a front view of rotor202. Leaf seals321have been omitted fromFIGS. 4A through 4Cfor convenience. In some embodiments, rotor202can be machined from a single piece of aluminum or other suitable material. Rotor202can be rotatably fixed relative to shaft102using a key (not shown), by machining splines in shaft102and corresponding grooves in the central hole of rotor202through which shaft102will extend, or using other suitable technique. Inlet port310is drilled into the front face of rotor202and intersects an internal channel311. As seen inFIG. 4B, a top view of rotor202and shaft102, channel311connects to a vent opening402in outer edge320of rotor202. Thus, air received from a source at the front side of rotor202can be directed through inlet310and internal passage311and out of vent402.

FIG. 4Cis a rear view of rotor202. Outlet port325is drilled into the rear face of rotor202and intersects an internal channel326. As seen inFIG. 4B, channel326connects to a vent opening401in outer edge320of rotor202. Thus, compressed air in a chamber bounded by outer edge320can be directed through vent401and internal passage326and out of outlet325. As also seen inFIG. 4C, neither inlet310nor channel311is accessible from the rear face of rotor202. Similarly, and as seen inFIG. 4A, neither outlet325nor channel326is accessible from the front face of rotor202.

FIGS. 4D through 4Fare front, top and rear views, respectively, of slotted rotor204. Rotor204has also been rotated so as to place slot342at top dead center, and leaf seals321have been omitted for convenience. As can be appreciated by comparingFIGS. 4D through 4FwithFIGS. 4A through 4C, slotted rotor204is similar to slotted rotor202. Port340is drilled into the front face of rotor204and intersects an internal channel341. Channel341connects to a vent opening403in outer edge350of rotor204. Thus, compressed air and combustion products received from a source at the front side of rotor204can be directed through inlet340and internal passage341and out of vent403. Outlet351intersects channel352, and channel352connects to a vent opening404in outer edge350. Thus, exhaust in an inter-rotor chamber bounded by outer edge350can be directed through vent404and internal passage352and out of outlet351. Neither inlet340nor channel341is accessible from the rear face of rotor204. Similarly, neither outlet351nor channel352is accessible from the front face of rotor204.

FIG. 5Ais a front view of main rotor201removed from engine100.FIG. 5Bis a cross-sectional view of main rotor201from the location indicated inFIG. 5A.FIG. 5Cis a different cross-sectional view of main rotor201from the second location indicated inFIG. 5A. For convenience, rotor201has been rotated approximately 30° from the position indicated inFIGS. 3A-3Dso as to place blade301at top dead center. Rotors201and203can be formed from aluminum or other suitable material. As seen inFIG. 5A, blade301extends downward and is visible through opening304. As seen inFIGS. 5B and 5C, blade301is attached to the inside of rotor201at inner perimeter wall302, inner front wall303and inner rear wall328.

AlthoughFIGS. 5A through 5Cshow rotor201as a monolithic element for simplicity, each of rotors201and203could be formed from two or more pieces that can be disassembled so as to allow insertion of a slotted rotor, and then reassembled so as to contain that slotted rotor.FIG. 5Dshows a rotor201′ according to one such embodiment.FIG. 5Eis an area cross-sectional view of rotor201′, from the location indicated inFIG. 5D, after disassembly. Rotor201′ is similar to rotor201, except that rotor201′ comprises a front portion513and a rear portion510that are attached with fasteners (e.g., screws)512. A gasket or other sealing compound could be placed between the adjoining surfaces of portions510and513.

FIGS. 6A through 6Fare partially schematic drawings showing relative positions of main rotor201and slotted rotor202at selected times during a complete revolution of rotors201and202. During a complete intake/compression cycle, rotors201and202will make two complete rotations (i.e., each will rotate 720°). Stated differently, each intake/compression cycle includes two rotational cycles. The first half of each cycle is an intake half-cycle. During the intake half-cycle, air is drawn into a first inter-rotor chamber between rotors201and202during a first revolution (i.e., the first 360° of rotation). The second half of each intake/compression cycle is a compression half-cycle. During the compression half-cycle, which occurs during a rotation that immediately follows the rotation of the intake half-cycle (i.e., the second 360° of rotation), air is compressed in a second inter-rotor chamber between the rotors and then released into channel242. Rotors201and202simultaneously perform two separate and overlapping intake/compression cycles as they rotate. During any given rotation, rotors201and202are performing the intake half-cycle of one intake/compression cycle and the compression half-cycle of a separate intake/compression cycle. This arrangement provides one power stroke for each 360° of rotation of the rotors.

Each ofFIGS. 6A through 6Fis an area cross-sectional view of rotors201and202taken from a plane passing through the center of rotors201and202(i.e., halfway between planes3B-3B and3C-3C ofFIG. 2). The view in each ofFIGS. 6A through 6Fis facing toward the rear of engine100. Manifolds305and330respectively lie in planes forward and rear of the sectioning plane used forFIGS. 6A-6F. The locations of manifolds305and330in those other planes are projected onto the sectioning plane used forFIGS. 6A-6Fwith broken lines. So as to distinguish between manifolds305and330, the projection of manifold305is shown with smaller broken lines.

Each of rotors201and202rotates counterclockwise inFIGS. 6A-6F. Torque from shaft102rotates slotted rotor202. The force of slotted rotor202against the side605of blade301rotates main rotor201. InFIG. 6A, both of rotors201and202are at top dead center. Rotors201and202are about to begin the intake half-cycle of one intake/compression cycle and the compression half-cycle of a separate intake/compression cycle. An inter-rotor compression chamber601has a volume defined by inner perimeter wall302of rotor201, by outer face320of rotor202, and by portions of front inner wall303and rear inner wall328of rotor202. Chamber601contains air that was drawn through manifold305, inlet310and channel311during an intake half-cycle that occurred in the immediately preceding revolution of rotors201and202.

InFIG. 6B, rotor202has rotated clockwise. Main rotor201has also rotated in response to the rotation of rotor202. Trunnion seal313has rotated slightly clockwise and blade301has withdrawn slightly from seal313. The volume of compression chamber601is reduced. Specifically, chamber601is bounded on one end by blade301and at the other end by an inter-rotor seal603resulting from the rolling contact (e.g., tangent or near tangent contact) between outer face320of rotor202and inner wall302of rotor201. As rotors201and202rotate, the ends of chamber601become closer and the volume of chamber601is thus reduced. The reduction of volume in chamber601compresses air contained in chamber601.

For convenience, the position of seal603is shown at the twelve o'clock position inFIGS. 6A-6F. In actuality, the precise position of seal603may be slightly to the right and/or left of the twelve o'clock position and will vary slightly as various of seals321approach and recede from the twelve o'clock position. Seals321are discussed below in connection withFIG. 8.

As also shown inFIG. 6B, separate inter-rotor intake chamber602is created as rotors201and202rotate past top dead center. The volume of chamber602is also bounded by blade301and by the inter-rotor seal603. As rotors201and202rotate, the ends of chamber602become more separated and the volume of chamber602expands. Inlet310coincides with manifold305throughout an entire rotation of rotor202. Accordingly, fresh air can flow from inlet305(FIG. 2), through inlet310and channel311, and into intake chamber602as the volume of chamber602expands.

InFIG. 6C, rotors201and202have both rotated 180° from top dead center. Intake chamber602has continued to expand and draw in fresh air through manifold305, inlet310and channel311. Compression chamber601has continued to contract, resulting in further compression of the air contained therein. Seal313has rotated clockwise so as to be in the same position (relative to slotted rotor202) as is shown inFIG. 6A. Blade301has reached the point of maximum withdrawal from slot312(seeFIG. 4A).

InFIG. 6D, rotors201and202have rotated further. Intake chamber602has continued to expand and draw in fresh air through manifold305, inlet310and channel311. Compression chamber601has continued to contract and compress air contained therein. Seal313has now rotated slightly counterclockwise, and blade310has begun to re-enter slot315. As also seen inFIG. 6D, outlet325is nearing the beginning of its coincidence with manifold330.

FIG. 6Eshows rotors201and202rotated to the point at which outlet325begins to coincide with manifold330. Because of this coincidence, compressed air in chamber601can more easily flow through channel326and outlet325into manifold330, and from manifold330into compressed air channel242(seeFIG. 2). Intake chamber602has continued to expand and draw in fresh air through manifold305, inlet310and channel311.

At this point in the rotation of rotors201and202, a valve in chamber243(FIG. 2) opens and allows compressed air to flow from channel242, chamber243and channel244into an expansion inter-rotor chamber of rotors203and204. This expansion and the operation of rotors203and204are further discussed below in connection withFIGS. 7A-7F. The opening and closing of the valve within chamber243, which valve could be a rotary valve or other type of valve, can be timed to the rotation of rotors201and202(and/or to the rotation of rotors203and204) by mechanical coupling to shaft102or to another rotating component, by gears, by a timing belt, by a camshaft, by an electrically controlled servomotor, or by other mechanism.

FIG. 6Fshows rotors201and202after they have completed the revolution begun inFIG. 6A. The intake/compression cycle for which the compression half-cycle began inFIG. 6Ahas now completed. The intake/compression cycle for which the intake half-cycle began inFIG. 6Ahas now completed its intake half-cycle and is about to begin its compression half-cycle. In particular, as rotors201and202again rotate through top dead center, chamber602will become a compression chamber. A new inter-rotor intake chamber will also be formed and will draw in fresh air as part of the intake half-cycle of a new intake compression cycle.

FIGS. 7A through 7Fare partially schematic drawings showing relative positions of main rotor203and slotted rotor204at selected times during a complete revolution of rotors203and204. During a complete expansion/exhaust cycle, rotors203and204will also make two complete rotations (i.e., each will rotate 720°). Stated differently, each expansion/exhaust cycle includes two rotational cycles. The first half of each expansion/exhaust cycle is an expansion half-cycle. During the expansion half-cycle, compressed air and combustion products are blown into a first inter-rotor chamber between rotors203and204during a first revolution (i.e., the first 360° of rotation). The second half of each expansion/exhaust cycle is an exhaust half-cycle. During the exhaust half-cycle, which occurs during a rotation that immediately follows the rotation of the expansion half-cycle (i.e., the second 360° of rotation), exhaust in a second inter-rotor chamber between the rotors is scavenged and forced out through exhaust port106. Rotors203and204simultaneously perform two separate and overlapping expansion/exhaust cycles as they rotate. During any given rotation, rotors203and204are performing the expansion half-cycle of one expansion/exhaust cycle and the exhaust half-cycle of a separate expansion/exhaust cycle.

The simultaneous and overlapping expansion/exhaust cycles in rotors203and204occur while simultaneous and overlapping intake/compression cycles occur in rotors201and202. However, a respective correspondence betweenFIGS. 6A-6Fand7A-7F is not necessarily intended. In other words, the rotational phase of rotors203and204represented in one ofFIGS. 7A-7Fending with a particular capital letter may or not be the rotational phase that rotors203and204would have when rotors201and202have the rotational phase represented in the one ofFIGS. 6A-6Fending with the same capital letter.

Each ofFIGS. 7A through 7Fis an area cross-sectional view of rotors203and204taken from a plane passing through the center of rotors203and204(i.e., halfway between planes3F-3F and3G-3G ofFIG. 2). The view in each ofFIGS. 7A through 7Fis facing toward the rear of engine100. Manifolds336and356respectively lie in planes forward and rear of the sectioning plane used forFIGS. 7A-7F. The locations of manifolds336and356in those other planes are projected onto the sectioning plane used forFIGS. 7A-7Fwith broken lines. So as to distinguish between manifolds336and356, the projection of manifold356is shown with smaller broken lines.

InFIG. 7A, both of rotors203and204are at top dead center. Rotors203and204are about to begin the expansion half-cycle of one expansion/exhaust cycle and the exhaust half-cycle of a separate expansion/exhaust cycle. The volume of an inter-rotor exhaust chamber701is defined by inner perimeter wall333of rotor203, by outer face350of rotor204, and by portions of front inner wall337and rear inner wall355of rotor204. Chamber701contains exhaust that remains after compressed air and combustion products were forced through manifold336, inlet340and channel341during the preceding revolution.

InFIG. 7B, rotors203and204have rotated clockwise as a result of the momentum from the previous revolution. Because of the rotation from top dead center, inlet340and manifold336coincide. Trunnion seal343has rotated slightly clockwise and blade334has withdrawn slightly from seal343. An inter-rotor expansion chamber702has also been created. The volume of chamber702is bounded at one end by blade334and at the other end by an inter-rotor seal705resulting from the rolling contact between outer face350of rotor204and inner wall333of rotor203. As with inter-rotor seal603discussed in connection withFIGS. 6B-6E, the position of seal705is for convenience shown at the twelve o'clock position inFIGS. 7B-7E. In actuality, the precise position of seal705will be slightly to the left and/or right of the twelve o'clock position and will vary slightly as various of seals321approach and recede from the twelve o'clock position.

Because inlet340and manifold336coincide, heated and compressed gas (air and combustion products) can easily flow from combustion chamber243, through channel244, manifold336, inlet340, channel341and vent opening403, and into expansion chamber702. The expansive pressure of this heated and compressed gas causes chamber702to further expand. In particular, the expansive pressure pushes blade334away from seal705so as to create more volume to accommodate the expanding gas. The resulting force causes rotors203and204to continue rotating.

As expansion chamber702expands, exhaust chamber701contracts. This contraction scavenges exhaust gases that remain from a previous expansion half-cycle (during the previous revolution) and pushes those scavenged exhaust gases through vent404, channel352, outlet351, manifold356and exhaust port106.

InFIG. 7C, inlet340still coincides with manifold336, and expanding gases continue to flow into chamber702. The resulting continued expansion of the chamber702volume continues to impart rotational forces on rotors203and204. Chamber701continues to contract, thereby continuing the scavenging and evacuation of exhaust gases. Seal343is still rotated clockwise, and blade334has withdrawn further from slot342.

InFIGS. 7D and 7E, rotors203and204have continued to rotate in response to expanding gases in chamber702. Exhaust chamber701has continued to contract and scavenge exhaust. Seal343has rotated counterclockwise and blade334has begun re-entry into slot342(seeFIG. 4D).

FIG. 7Fshows rotors203and204after they have completed the revolution begun inFIG. 7A. The expansion/exhaust cycle for which the exhaust half-cycle began inFIG. 7Ahas now completed. The expansion/exhaust cycle for which the expansion half-cycle began inFIG. 7Ahas now completed its expansion half-cycle and is about to begin its exhaust half-cycle. In particular, as rotors203and204again rotate through top dead center, inter-rotor chamber702will become an exhaust chamber. A new inter-rotor expansion chamber will also be formed and will receive a new injection of heated and compressed gas from combustion chamber243as part of the expansion half-cycle of a new expansion/exhaust cycle.

FIG. 8Ais an enlarged view from the location indicated inFIG. 3Band shows additional details of a leaf seal321. Seal321extends across the entire width of outer surface320of rotor202. Seal321includes a flexible leaf element801that is biased away from outer surface320. A base end802of leaf element801is held in place by a bracket803, with bracket803secured to rotor202using one or more fasteners804. Bracket803and fastener(s)804are sufficiently recessed so that leaf element801lies flush (or nearly flush) with surface320as surface320rolls relative to inner circumferential surface302of rotor201.

FIG. 8Bis similar toFIG. 8A, but shows a seal321after the relative rotation of rotors201and202has brought seal321near the point at which the rotors will be in rolling contact. The free end806of leaf element801is forced against wall302of rotor201. This creates a seal that prevents flow of gases from side807to side808.

Rotor204similarly has a plurality of leaf seals321that operate similar to the seals321of rotor202. In some embodiments, a rotor has at least five seals321, with each of those five seals and the center of the slot having radially even positions. In particular, the radius from rotor centerline through the slot center is N*60° for each of the radii passing through the centers of seals321, where N=1, 2, 3, 4, or 5. Additional seals321could be included. Leaf element801could be formed from a nickel-based or cobalt alloy material, and could be ribbon shim stock coated with low friction diamond-like carbon or other coatings of the rolling contact surface. The leaf element could be hinged or rigidly affixed to the slotted rotor.

FIG. 8Cshows a leaf element801′ according to another embodiment.FIG. 8Cshows element801′ just after the portion of surface320′ into which element801′ is inserted has rolled past the point of rolling contact with the inner perimeter surface of a main rotor201′. Surface320′ could be a surface of a slotted rotor similar to rotor202. Rotor201′ could be similar to rotor201. Element801′ could be formed from materials similar to those usable for element801.

Shaft102of engine100can be coupled to a pump, a turbocharger or another device and used to provide mechanical power to that coupled device. Power from shaft102could also or alternatively be coupled to a transmission and used to provide motive power. In other embodiments, an engine may not include a shaft. For example,FIGS. 9A-9Care front, side and rear views, respectively, of a combination rotary engine and motor/generator900according to another embodiment. Similar to engine100, engine900includes a housing901, an air intake port905located in a front face903, and an exhaust port906located in a rear face904. Unlike engine100, however, engine900does not include an external shaft. Engine900could, e.g., be used solely to generate electrical power. As withFIGS. 1A-1C,FIGS. 9A-9Cdo not show various elements such as fuel line connections, wiring harness connections, etc.

FIG. 10is a cross-sectional view of engine900from the location indicated inFIG. 9A. Engine900includes an intake/compression main rotor1001and an intake/compression slotted rotor1002. The rear portion of engine900includes an expansion/exhaust main rotor1003and an expansion/exhaust slotted rotor1004. Each of main rotors1001and1003rotates about a main rotor axis AMR900. Each of slotted rotors1002and1004rotates about a slotted rotor axis ASR900. Unlike rotors202and204of engine100, however, rotors1002and1004are not attached to an axle. Rotor1002is rotatably supported by bearings1021and rotor1004is rotatably supported by bearings1023. Rotors1001and1003are connected to one another by a flange1057, which connection coordinates the rotation of the rotor sets in engine900.

Rotors1001and1003are rotatably supported by bearings1013,1015,1017and1019. An armature1008is attached to rotor1001and rotates within a stator1009. An armature1010is attached to rotor1003and rotates within a stator1011. Intake905supplies air to a manifold1006that is similar to manifold305of engine100. Rotor1001is similar to rotor201of engine100. Other than being rotatably mounted solely on bearings1021instead of an axle, rotor1002is similar to rotor202of engine100and has similar ports, channels, leaf seals, etc. Compressed air from rotors1001and1002is output to a manifold (not shown) that is similar to manifold330of engine100, which compressed air flows through a channel1042to a combustion chamber1043similar to combustion chamber242. Heated compressed gases (air and combustion products) flow from chamber1043through channel1044to a manifold (not shown) similar to manifold336.

Rotor1003is similar to rotor203of engine100. Other than being rotatably mounted solely on bearings1023instead of an axle, rotor1004is similar to rotor204of engine100and has similar ports, channels, leaf seals, etc. Heated compressed gases enter rotor1004in a manner similar to that of rotor204and cause rotors1003and1004to rotate. Exhaust is scavenged from rotors1003and1004, in a manner similar to that described in connection with rotors203and204, and forced out through a manifold1007(similar to manifold356) and exhaust port906.

Other embodiments include numerous additional variations. As but one example, channels such as channels311and352need not be formed in the manner shown in connection with engine100. In some embodiments, an intake channel could be formed as a groove in the front face of the intake/compression slotted rotor and the exhaust channel could be formed as a groove in the rear face of the expansion/exhaust slotted rotor.

In still other embodiments, the main rotors in a combination rotary engine and motor/generator are attached to a shaft.FIGS. 11A-11Care front, side and rear views, respectively, of a combination rotary engine and motor/generator1100according to one such embodiment. Similar to engines100and900, engine1100includes a housing1101, an air intake port1105located in a front face1103, and an exhaust port1106located in a rear face1104. A shaft1102extends through front and rear faces1103and1104and is coupled to main rotors within engine1100. As with previously-described embodiments,FIGS. 11A-11Cdo not show various elements such as fuel line connections, coolant line connections, wiring harness connections, etc.

FIG. 12is a cross-sectional view of engine1100from the location indicated inFIG. 11A. The front portion of engine1100includes an intake/compression main rotor1201and an intake/compression slotted rotor1202. The rear portion of engine1100includes an expansion/exhaust main rotor1203and an expansion/exhaust slotted rotor1204. Each of main rotors1201and1203is connected to shaft1102by a blade, as described in more detail in connection withFIGS. 13A and 13E. Shaft1102is rotatably supported by bearings1221and1223. Main rotor1201is rotatably supported by bearings1213and1215. Main rotor1203is rotatably supported by bearings1217and1219.

Slotted rotor1202is located within main rotor1201and is rotatably supported by bearings1286and1285. Slotted rotor1204is located within main rotor1203and is rotatably supported by bearings1284and1283. Slotted rotors1202and1204rotate about an axis ASR1100. Main rotors1201and1203, as well as shaft1102, rotate about an axis AMR1100.

Fresh air is drawn in through intake1105and is supplied to a circular manifold1206. An opening in the forward face of main rotor1201, which opening is described in connection withFIG. 14A, allows fresh air to flow into an inter-rotor intake chamber created between rotors1201and1202. As an inter-rotor compression chamber between rotors1201and1202compresses that air, a slot in the rear wall of main rotor1201(described in connection withFIG. 14C) allows that compressed air to flow into a compressed air channel1242. Channel1242feeds into a combustion chamber/valve1243. Fuel is also added in chamber1243. After that fuel and compressed air mixture is ignited, the valve of chamber1243allows the resulting heated and compressed gas to flow through channel1244.

Channel1244connects to an arcuate manifold in a wall of housing1101that adjoins the front face of main rotor1203. That arcuate manifold is shown inFIG. 13D. An opening in the front face of main rotor1203allows that heated and compressed gas to enter an inter-rotor expansion chamber between rotors1203and1204. As that gas expands, the resulting force causes rotors1203and1204to rotate. After the gases expand, the exhaust is scavenged in an inter-rotor exhaust chamber formed by rotors1203and1204and then forced out through a circular manifold1207and exhaust port106.

Ring seals1298and1299are located in a wall of housing1101that faces the front of main rotor1201. Seals1298and1299help ensure that only fresh air from intake1105is supplied to manifold1206. Ring seals1295and1294are located in a wall of housing1101that faces the rear of main rotor1201. Seals1295and1294help to contain air compressed between rotors1201and1202so as to prevent that compressed air from leaking into portions of housing1101other than channel1242. Ring seal1297in the front of slotted rotor1202and ring seal1296in the rear of slotted rotor1202help prevent compressed air from leaking out of a compression chamber formed by rotors1201and1202.

Ring seals1293and1292are located in a wall of housing1101that faces the front of main rotor1203. Seals1293and1292help to contain heated and compressed gases flowing from channel1244so as to direct those gases into an inter-rotor expansion chamber between rotors1203and1204. Ring seals1289and1288are located in the wall of housing1101that faces the rear of main rotor1203. Seals1289and1288help to direct exhaust through port1106. Ring seal1291in the front of slotted rotor1204and ring seal1290in the rear of slotted rotor1204help prevent expanding gasses from leaking out of an inter-rotor expansion chamber formed by rotors1203and1204.

FIG. 13Ais a cross-sectional view taken from the first location indicated inFIG. 12. As seen more clearly inFIG. 13A, intake1105connects to manifold1206. Manifold1206extends around the entire circumference of a portion of housing1101that faces the front of main rotor1201. In some embodiments, a check valve could be located in intake1105to prevent backflow from rotors1201and1202from passing through intake1105.

FIG. 13Bis a cross-sectional view taken from second location indicated inFIG. 12. A blade1301connects the inner perimeter wall1302of main rotor1201to shaft1102. Two halves1313aand1313bof a cylindrical split trunnion seal1313are contained in a slot1312of slotted rotor1202. Blade1301slides between halves1313aand1313b, and seal1313can rotated within slot1312. Seal1313operates similar to seal313described in connection with engine100and prevents gas from passing through slot1312. As described below in connection withFIGS. 16A-16E, seal1313allows creation of intake and compression inter-rotor chambers between wall1302and outer surface1320of slotted rotor1202. Although not shown, leaf seals similar to leaf seals321could be included in surface1320.

FIG. 13Cis a cross-sectional view taken from the third location indicated inFIG. 12. As seen inFIG. 13C, an arcuate manifold1330extends in a small arc in a portion of housing that faces the rear of main rotor1201. Manifold1330is connected to channel1242.

FIG. 13Dis a cross-sectional view taken from the fourth location indicated inFIG. 12. As seen inFIG. 13D, an arcuate manifold1336extends in a small arc in a portion of housing1101that faces the front of main rotor1203. Manifold1336is connected to channel1244. In some embodiments, arcuate manifold1336extends over approximately 170° of the rotation of rotor1204so as to minimize back pressure when a valve in chamber1243admits the next charge of heated and compressed air into chamber1243and then into an inter-rotor chamber of rotors1203and1204.

FIG. 13Eis a cross-sectional view taken from the fifth location indicated inFIG. 12. A blade1334connects the inner perimeter wall1333of main rotor1203to shaft1102. Two halves1343aand1343bof a cylindrical split trunnion seal1343are contained in a slot1342of slotted rotor1204. Blade1334slides between the halves of seal1343, and seal1343can rotated within slot1342. Seal1343operates similar to seal343described in connection with engine100and prevents gas from passing through slot1342. As described below in connection withFIGS. 17A-17E, seal1343allows creation of expansion and exhaust inter-rotor chambers between wall1333and outer circumferential surface1320of slotted rotor1204. Although not shown, leaf seals similar to leaf seals321could also be included in surface1320.

FIG. 13Fis a cross-sectional view taken from the sixth location indicated inFIG. 12. As seen more clearly inFIG. 13F, exhaust port1106connects to manifold1207. Manifold1207extends around the entire circumference of a portion of housing1101that faces the rear of main rotor1203.

FIG. 14Ais a front view of main rotor1201removed from engine1100but attached to shaft1102.FIG. 14Bis a cross-sectional view of main rotor1201and shaft1102from the location indicated inFIG. 5A.FIG. 14Cis a rear view of main rotor1201removed from engine1100but attached to shaft1102. For convenience, rotor1201has been rotated approximately 30° from the position indicated inFIG. 13Bso as to place blade1301at top dead center. Rotor1203may be substantially identical to rotor1201. Rotors1201and1203can be formed from aluminum or other suitable material. As seen inFIG. 14A, blade1301extends downward and is connected to shaft1102. As seen inFIG. 14B, blade1301is attached to the inside of rotor1201at the inner perimeter wall1302, the inner front wall1410and the inner rear wall1411.

An intake opening1499in the front1498of rotor1201cooperates with manifold1206so as to allow air into an inter-rotor intake chamber between rotors1201and1202. A similar opening in the front of rotor1203cooperates with manifold1336so as to allow heated and compressed gases to flow into an inter-rotor expansion chamber between rotors1203and1204. An outlet opening1497in the rear1496of rotor1201cooperates with manifold1330so as to allow heated and compressed gas to flow from an inter-rotor compression chamber between rotors1201and1202into channel1242. A similar opening in the rear of rotor1203cooperates with manifold1207so as to allow exhaust to flow from an inter-rotor exhaust chamber between rotors1203and1204into exhaust port1106.

AlthoughFIGS. 14A through 14Cshow rotor1201and shaft1102as a monolithic element for simplicity, each of rotors1201and1203could be formed from multiple pieces that can be disassembled so as to allow insertion of a slotted rotor, and then reassembled so as to contain that slotted rotor. An end of blade1301could rest within a groove cut in shaft1102. Similarly, an end of blade1334of main rotor1203could rest within another groove cut in shaft1102.

FIGS. 15A-15Care front, top and rear views, respectively, of slotted rotor1202. Slotted rotor1204is substantially identical. For convenience, rotor1202is rotated approximately 30° from the position shown inFIGS. 13Bso as to place slot1312at top dead center. A first notch1501is formed in the front of rotor1202and cooperates with opening1499in rotor1201. A second notch1502is formed in the rear of rotor1202and cooperates with opening1497in rotor1201. A notch in the front of rotor1204similar to notch1501cooperates with an opening in rotor1203similar to opening1499in rotor1201. A notch in the rear of rotor1204similar to notch1502cooperates with an opening in rotor1203similar to opening1497in rotor1201.

FIGS. 16A through 16Eare partially schematic drawings showing relative positions of main rotor1201and slotted rotor1202at selected times during a complete revolution of rotors1201and1202. Similar to engine100, rotors1201and1202will make two complete rotations (i.e., each will rotate 720°) during an intake/compression cycle. Stated differently, each intake/compression cycle includes two rotational cycles. The first half of each cycle is an intake half-cycle. During the intake half-cycle, air is drawn into an inter-rotor intake chamber between rotors1201and1202during a first revolution (i.e., the first 360° of rotation). The second half of each intake/compression cycle is a compression half-cycle. During the compression half-cycle, which occurs during a rotation that immediately follows the rotation of the intake half-cycle (i.e., the second 360° of rotation), the intake chamber becomes a compression chamber and the air is compressed. Rotors1201and1202simultaneously perform two separate and overlapping intake/compression cycles as they rotate. During any given rotation, rotors1201and1202are performing the intake half-cycle of one intake/compression cycle and the compression half-cycle of a separate intake/compression cycle.

Each ofFIGS. 16A through 16Eis an area cross-sectional view of rotors1201and1202taken from the plane used forFIG. 13B. The view in each ofFIGS. 16A through 16Eis facing toward the rear of engine1100. For simplicity, the locations of manifolds1206and1330, as well as the locations of openings1499and1497, have not been projected onto the sectioning planes ofFIGS. 16A-16E. However, the locations of those manifolds and openings can be readily deduced by comparingFIGS. 16A-16EwithFIGS. 13A-13C,14A and14C.

Each of rotors1201and1202rotates counterclockwise inFIGS. 16A-16E. Torque from shaft1102rotates main rotor1201. The force of blade1301rotates slotted rotor1202. InFIG. 16A, both of rotors1201and1202are at top dead center. Rotors1201and1202are about to begin the intake half-cycle of one intake/compression cycle and the compression half-cycle of a separate intake/compression cycle. An inter-rotor compression chamber1601has a volume defined by inner perimeter wall1302of rotor1201, by outer face1320of rotor1202, and by portions of front inner wall1410and rear inner wall1411. Chamber1601contains air that was drawn through manifold1206and opening1499in an intake half-cycle that occurred during the immediately preceding revolution of rotors1201and1202.

InFIG. 16B, rotors1201and1202have rotated counterclockwise. Trunnion seal1313has rotated slightly clockwise and blade1301has started to emerge from slotted rotor1202. The volume of compression chamber1401is reduced. Specifically, chamber1401is bounded on one end by blade1301and at the other end by an inter-rotor seal1605resulting from the rolling contact between outer face1320of rotor1202and inner wall1302of rotor1201. As rotors1201and1202rotate, the ends of chamber1601become closer and the volume of chamber1601is thus reduced. The reduction of volume in chamber1601compresses air contained in chamber1601.

In some embodiments, compression chamber1401remains in fluid communication with channel1242(FIG. 12) throughout the compression cycle. A valve in chamber1243remains closed until a point in the cycle at which compressed gas is allowed to flow from chamber1243, into channel1244, and into an inter-rotor chamber of rotors1203and1204.

As also shown inFIG. 16B, separate inter-rotor intake chamber1602is created as rotors1201and1202rotate past top dead center. The volume of chamber1602is also bounded by blade1301and by the rolling contact seal1605. As rotors1201and1202rotate, the ends of chamber1602become more separated and the volume of chamber1602expands. Fresh air flows from manifold1206and into intake chamber1602as the volume of chamber1602expands.

InFIG. 16C, rotors1201and1202have both rotated 180° from top dead center. Intake chamber1602has continued to expand and draw in fresh air through manifold1206and opening1499. Compression chamber1601has continued to contract, resulting in further compression of the air contained therein. Seal1313has rotated clockwise so as to be in the same position (relative to slotted rotor1202) as is shown inFIG. 16A. Blade1301has reached the point of maximum withdrawal from slot1312.

InFIG. 16D, rotors1201and1202have rotated further. Intake chamber1602has continued to expand and draw in fresh air through manifold1206. Compression chamber1601has continued to contract and compress air contained therein. Seal1313has now rotated slightly counterclockwise, and blade1301has begun to re-enter slot1312. At approximately this point in the compression cycle, fuel is injected into chamber1243(FIG. 12) and ignited, and the valve in chamber1243is opened so as to allow the compressed air to escape from chamber1601, through opening1497, channel1242, chamber1243, channel1244, manifold1336, and into an inter-rotor chamber of rotors1203and1204. Operation of rotors1203and1204is discussed in connection withFIGS. 17A through 17E.

FIG. 16Eshows rotors1201and1202after they have completed the revolution begun inFIG. 16A. The intake/compression cycle for which the compression half-cycle began inFIG. 16Ahas now completed. The intake/compression cycle for which the intake half-cycle began inFIG. 16Ahas now completed its intake half-cycle and is about to begin its compression half-cycle. In particular, as rotors1201and1202again rotate through top dead center, chamber1602will become a compression chamber. A new inter-rotor intake chamber will also be formed and will draw in fresh air as part of the intake half-cycle of a new intake compression cycle.

FIGS. 17A through 17Eare partially schematic drawings showing relative positions of main rotor1203and slotted rotor1204at selected times during a complete revolution of rotors1203and1204. During a complete expansion/exhaust cycle, rotors1203and1204will also make two complete rotations (i.e., each will rotate 720°). Stated differently, each expansion/exhaust cycle includes two rotational cycles. The first half of each expansion/exhaust cycle is an expansion half-cycle. During the expansion half-cycle, compressed air and combustion products are blown into an inter-rotor expansion chamber between rotors1203and1204as rotors1203and1204undergo a first revolution (i.e., the first 360° of rotation). The second half of each expansion/exhaust cycle is an exhaust half-cycle. During the exhaust half-cycle, which occurs during a rotation that immediately follows the rotation of the expansion half-cycle (i.e., the second 360° of rotation), the expansion chamber becomes and exhaust chamber. Exhaust in that exhaust chamber is scavenged and forced out through exhaust port1106. Rotors1203and1204simultaneously perform two separate and overlapping expansion/exhaust cycles as they rotate. During any given rotation, rotors1203and1204are performing the expansion half-cycle of one expansion/exhaust cycle and the exhaust half-cycle of a separate expansion/exhaust cycle.

The simultaneous and overlapping expansion/exhaust cycles in rotors1203and1204occur while simultaneous and overlapping intake/compression cycles occur in rotors1201and1202. However, a respective correspondence betweenFIGS. 16A-16Eand17A-17E is not necessarily intended. In other words, the rotational phase of rotors1203and1204represented in one ofFIGS. 17A-17Eending with a particular capital letter may or not be the rotational phase that rotors1203and1204would have when rotors1201and1202have the rotational phase represented in the one ofFIGS. 16A-16Eending with the same capital letter.

Each ofFIGS. 17A through 17Eis an area cross-sectional view of rotors1203and1204taken from the plane used forFIG. 13E. The view in each ofFIGS. 17A through 17Eis facing toward the rear of engine1100. For simplicity, the locations of manifolds1336and1207, as well as the locations of openings in rotor1203similar to openings1499and1497in rotor1201, have not been projected onto the sectioning planes ofFIGS. 17A-17E. However, the locations of those manifolds and openings can be readily deduced by comparingFIGS. 17A-17EwithFIGS. 13D-13F,14A and14C.

InFIG. 17A, both of rotors1203and1204are at top dead center. Rotors1203and1204are about to begin the expansion half-cycle of one expansion/exhaust cycle and the exhaust half-cycle of a separate expansion/exhaust cycle. The volume of an inter-rotor exhaust chamber1701is defined by inner perimeter1333of rotor1203, by outer face1350of rotor1204, and by portions of front and rear inner walls of rotor1203. Chamber1701contains exhaust that remains after compressed air and combustion products were forced through manifold1336and an opening in the front of rotor1203(similar to opening1499in the front of rotor1201) during the preceding revolution.

InFIG. 17B, rotors1203and1204have rotated clockwise as a result of the momentum from the previous revolution. Trunnion seal1343has rotated slightly clockwise and blade1334has withdrawn slightly from slot1342. An inter-rotor expansion chamber1702has also formed. The volume of chamber1702is bounded at one end by blade1334and at the other end by an inter-rotor seal1705resulting from the rolling contact between outer face1350of rotor1204and inner face wall of rotor1203.

Because manifold1336coincides with the opening in the front of rotor1203, heated and compressed gas (air and combustion products) can easily flow from combustion chamber1243, through channel1244, manifold1336, and the rotor1203front opening and into expansion chamber1702. The expansive pressure of this heated and compressed gas causes chamber1702to further expand. In particular, the expansive pressure pushes blade1334away from seal1705so as to create more volume to accommodate the expanding gas. The resulting force causes rotors1203and1204to continue rotating.

As expansion chamber1702expands, exhaust chamber1701contracts. This contraction forces exhaust gases that remain from a previous expansion half-cycle (during the previous revolution) through an opening in the rear of rotor1203(similar to opening1497in the rear of rotor1201), manifold1207and exhaust port1106.

InFIG. 17C, rotors1203and1204have both rotated 180° from top dead center. Continued expansion of gas in chamber1702continues to impart rotational forces on rotors1203and1204. Chamber1701continues to contract, thereby continuing the scavenging and evacuation of exhaust gases. Seal1343has rotated clockwise so as to be in the same position (relative to slotted rotor1204) as is shown inFIG. 17A. Blade1334has reached the point of maximum withdrawal from slot1342.

InFIG. 17D, rotors1203and1204have continued to rotate in response to expanding gases in chamber1702. Exhaust chamber1701has continued to contract and scavenge exhaust. Seal1343has rotated counterclockwise and blade1334has begun re-entry into slot1342.

FIG. 17Eshows rotors1203and1204after they have completed the revolution begun inFIG. 17A. The expansion/exhaust cycle for which the exhaust half-cycle began inFIG. 17Ahas now completed. The expansion/exhaust cycle for which the expansion half-cycle began inFIG. 17Ahas now completed that expansion half-cycle and is about to begin its exhaust half-cycle. In particular, as rotors1203and1204again rotate through top dead center, chamber1702will become an exhaust chamber. A new inter-rotor expansion chamber will also be formed and will receive a new injection of heated and compressed gas from combustion chamber1243as part of the expansion half-cycle of a new expansion/exhaust cycle.

FIG. 20Ais a cross-sectional view of a combination engine and motor/generator2000.FIG. 20Bis a cross-sectional view taken from the location shown inFIG. 20A. Engine2000includes main rotors2001and2003and slotted rotors2002and2004rotatably supported by bearings in a housing2059. Engine2000is similar to engine1100, except that rotors2001and2003are connected to each other and to a shaft2092. This connection reduces the torque on the main rotor blades (e.g., blade2093as shown inFIG. 20B).

In the embodiments described thus far, armatures and stators for a motor/generator encircle the main rotors of a rotary internal combustion engine and are contained in the same housing. Other embodiments include rotary internal combustion engines similar to those previously described, but in which motor/generator components are included within the same housing but do not encircle the main rotors. One example of such an embodiment is shown inFIG. 18.FIG. 18is a cross-sectional view taken from a location similar to the locations used forFIGS. 2,10and12. Rotary internal combustion engine1800is similar to engine1101, but lacks armatures and stators that encircle the main rotors. A separate motor/generator1880(having armature1808and stator1809) is coupled to a shaft1802of engine1800. In still other embodiments, a separate motor/generator in a separate housing can be coupled to the shaft of a rotary internal combustion engine.

In the embodiments ofFIGS. 1-18,20A and20B, each main rotor included a single blade. In other embodiments, a main rotor may have additional blades.FIG. 19is a partially schematic cross-sectional view of the main and slotted rotors from one such embodiment.FIG. 19shows a main rotor1901having a fixed blade1979and two swinging blades1978and1977. Fixed blade1979fits within a split trunnion seal1913in slot1912. As rotors1901and1902rotate, blade1979moves within slot1912in a manner similar to that described in connection with blade301. Blade1978fits within a split trunnion seal1976in slot1975. End1960of blade1978is captured in a groove1961and acts as a hinge pivot for blade1978. Blade1977fits within a split trunnion seal1974in slot1973. End1962of blade1977is captured in a groove1963and acts as a hinge pivot for blade1977. The sides of blade1979are fixed to the inner walls of main rotor1901in a manner similar to that shown in connection with rotor201. The sides of blades1978and1977form sliding seals that swing across the inner walls of main rotor1901.

The addition of blades1978and1977creates two additional inter-rotor chambers between rotors1901and1902. In a main/slotted rotor pair used for compression, these additional chambers can be used for additional compression stages. In a main/slotted rotor pair used for expansion, these additional chambers can be used for additional expansion stages. Other embodiments include main rotors with a single fixed blade and a single swing blade. Other embodiments include main rotors with more than two swing blades.

FIGS. 21A-21Fare partially schematic drawings showing relative positions of a main rotor2101and a slotted rotor2102according to another embodiment at selected times during a rotational cycle.FIGS. 21A-21Fare cross-sectional views based on a sectioning plane similar to the sectioning planes used in connection withFIGS. 6A-6F,7A-7F,16A-16E and17A-17E.

Rotors2101and2102are similar to rotors1201and1202(and to rotors1203and1204) in that a blade2193is fixed to an inside perimeter surface of main rotor2101and rotates about the same axis as main rotor2101. Seal2113is similar to seals1313and1343. Unlike the embodiment of rotors1201and1202, however, blade2193is attached to an inner hub rotor2191. Hub rotor2191is attached to a shaft2192. Shaft2192can be coupled to another group of rotors and/or to external components. Main rotor2101, hub rotor2191, shaft2192and blade2193all rotate about a common axis (which common axis is centered on shaft2192inFIGS. 21A-21F). Slotted rotor2102rotates about another axis that is parallel to and offset from that common axis.

Hub rotor2191and blade2193operate so as to create two additional chambers that contract and expand as the rotors rotate. In particular, an outer surface of hub rotor2191makes rolling contact with an inner perimeter wall of slotted rotor2102so as to create an inter-rotor seal2185. Leaf seals could also be included on the outer surface of hub rotor2191to help create seal2185. As seen inFIG. 21A, two interior chambers2183and2184exist when the rotors are at top dead center. Each of chambers2183and2184is bounded at ends by seal2185and by blade2193. The front and rear sides of chambers2183and2184could be formed by interior surfaces of main rotor2101and/or by interior surfaces of a housing (not shown). An outer chamber2181(similar to chambers1601and1701) is also visible inFIG. 21A.

FIG. 21Fshows rotors2101,2102and2191returned to top dead center. Inner chamber2184is now similar to chamber2183inFIG. 21A. Inner chamber2186is now similar to chamber2184inFIG. 21A. Outer chamber2181has vanished, and outer chamber2182is now similar to chamber2181inFIG. 21A.

An arrangement of rotors similar to rotors2101,2102and2191can be used, with appropriate ducting and manifold(s), to combine intake/compression and power/exhaust into one set of rotors. For example, inner chambers could be used for intake and compression, with compressed air from an inner chamber ducted to an expansion outer chamber. An arrangement of rotors similar to rotors2101,2102and2191could alternatively be used for multi-stage compression or for multi-stage expansion.

Although various embodiments include engines having one main/slotted rotor pair for intake and compression and another main/slotted rotor pair for expansion and exhaust, other embodiments may have different configurations. An embodiment can include a main/slotted rotor pair such as is described in a preceding embodiment, but which is not used with another main/slotted rotor pair. For example, a main/slotted rotor pair could be coupled to an electric motor and used as a compressor. As another example, a main/slotted rotor pair could be connected to a source of surplus heated gas (e.g., gas bled from a gas turbine engine) and used as an auxiliary power unit. An embodiment could also have one or more stages of compressive main/slotted rotor pairs coupled to one or more stages of expansion main/slotted rotor pairs.

Still other embodiments may include multiple slotted rotors within a single main rotor and/or having one or more swing blades, such as are described in the aforementioned provisional patent application 61/313,833.

In some embodiments, a rotating valve or other type of valve could be located in an intake port (e.g., any ports105,905or1105) and timed with the rotation of an intake/compression rotor pair so as to cutoff air intake at certain points in a rotational cycle. In embodiments in which two or more main/slotted rotor pairs are used in an engine, the rotational cycles of the rotor pairs need not be in phase (e.g., one pair could be at top dead center while another pair is off top dead center). In at least some embodiments, however, the phases of an intake/compression rotor pair and an expansion/exhaust rotor pair are timed so that there is sufficient volume in an inter-rotor exhaust chamber to accept heated and compressed gas released by a valve in a channel between the two rotor pairs. In some embodiments, channels within a shaft could be used, in conjunction with one or more valves inside of a slotted rotor, to facilitate inflow to and outflow from inter-rotor chambers.

Internal combustion engines and other systems utilizing main and slotted rotor pairs such as are described above can offer numerous advantages. Such systems may require fewer moving components and seals. Known low friction and/or self-lubricating materials can be used for surfaces in sliding or rolling contact so as to further reduce energy loss, heating and wear. Positive displacement geometries according to some embodiments may provide over 270 degrees of compression of the intake air or of a fuel/air mixture and combustion gas expansion during each 360 degree blade rotation. Chamber dimensions and fluid transfer ports can be sized for intake air compression ratios from, e.g., 6 to 20, and combustion gas exhaust at near atmospheric pressure. Energy efficient operation and low exhaust emissions can be achieved using conventional and alternative fuels. The use of hard, durable, low friction materials and coatings on load bearing surfaces can provide an engine that is able to operate reliably with oil lubrication, fuel lubrication, or perhaps un-lubricated. Embodiments can include engines and other systems able to operate at high rotational speeds (e.g., 60,000 rpm or more). Engines and other systems according to various embodiments can include rotors of widely varying size. For example, some embodiments may include main rotors of less than one inch in diameter. As another example, some embodiments may have main rotors with diameters of several feet or more.

A rotary engine and motor/generator according to at least some embodiments would be compact and lightweight, have a high power density, and could provide an efficient power source for a hybrid electric vehicle or other applications. Main and slotted rotor pairs such as those described herein can also be incorporated into fluid compressors, fluid pumps, fluid driven motor/generators, turbochargers, and other systems.

Some embodiments may utilize fuel as a lubricant and/or to increase blade seals. Internal combustions engines according to various embodiments can use various fuels (e.g., gasoline, diesel, biofuels, other alternative fuels).

Set forth below is a non-exhaustive list of features that may be present in some of the above described embodiments and/or in other embodiments. All embodiments need not have all of the features described below (or above), and the below listing is not intended as a listing of essential features.A rotary internal combustion engine can include a housing with one or more cavities. Each cavity may contain a main rotor, a smaller slotted rotor mounted on a parallel axis offset with respect to the main rotor axis, intake and exhaust ports, a combustion chamber with fuel injector(s) or a carburetor, an ignition source (e.g., a spark plug, glow plug, or compression heating, depending on the fuel). A blade can be mechanically attached and sealed to the interior radial surface of the main rotor and to the interior sides of a cavity within the main rotor. A slot in the slotted rotor is sealed to the blade side surfaces, and the slot seals slide reciprocally along the blade with each rotation of the rotors. As the main rotor and the slotted rotor rotate at the same rotational velocity (rpm), a portion of the exterior surface of the slotted rotor maintains near contact with a portion of the interior surface of the main rotor cavity, thereby creating inter-rotor chambers on opposite sides of the blade that expand and contract with each rotation. The changing volumes of these sealed chambers can perform four-cycle internal combustion engine functions of air or fuel-air mixture intake, compression, combustion-expansion, and exhaust.An internal combustion engine may or may not include a power shaft, and may or may not include an integrated motor/generator. The motor/generator may include an armature located on an outer surface of a main rotor and a stator located on an inside surface of the housing surrounding the main rotor. The combination of an efficient, light weight, high power density engine and motor/generator, with the addition of a battery for starting the engine and for providing and storing electrical power, would be suitable for, e.g., a hybrid electric vehicle or other generator set applications. Drive train power for a hybrid electric vehicle could be provided by the rotary internal combustion engine, the motor/generator, a separate electric traction motor, or any combination of the these elements.In addition to a fixed main rotor blade, additional blades can be added that extend through transverse slots in the slotted rotor, or terminate in transverse slots in the slotted rotor. The additional blades can be pivotally attached by hinge fittings to the main rotor axel or hub, or to the interior surface of the main rotor drum.A tangential or near tangential contact between the exterior surface of a slotted rotor and the radially interior surface of a main rotor, in combination with a blade, can define crescent-shaped sealed working inter-rotor chambers. In certain embodiments and applications, a tangential or near tangential contact between a radially interior surface of a slotted rotor and an exterior surface of the main rotor hub, in combination with the blade, may define radially interior sealed working chambers. Transversely-mounted, evenly or non-evenly spaced, limited extension radial seals can be placed around the inside surface of the main rotor cavity or the outside surface of the slotted rotor. The spacing and radial extension of the seals could be proportioned to ensure that at least one seal is always in sealed contact between the inside surface of the main rotor cavity and the outside surface of the slotted rotor between the intake and exit ports. For example, rearward facing pressure compensated leaf seals could be spaced at +/−30 degrees from the main rotor blade, and four additional leaf seals at 60 degree radial spacing between these two seals. Similarly, pressure compensated forward facing leaf seals could be located at 60 degree intervals along the inside surface of the main rotor cavity or the outside surface of the slotted rotor. In certain embodiments, the limited radial extension seals around the inside surface of the main rotor cavity or the outside surface of the slotted rotor could be leaf seals, foil seals, hinged swing seals, sliding vane seals, roller seals, or the like. The seals between the blade sides and the slot in the slotted rotor could be industry standard blade seal materials. The sliding surfaces of the seals could preferably be low friction self-lubricated, fuel lubricated, or un-lubricated material.An engine or other system could include a single shaft mounted on the slotted rotor, with the main rotor being mounted on an offset parallel axis relative to the slotted rotor axis. An engine or other system could include a single shaft mounted on the main rotor, with the slotted rotor being mounted on an offset parallel axis relative to the main rotor axis. An engine or other system may lack a shaft; the main rotor could be mounted for rotation in the end plates of the housing, and the slotted rotor mounted for rotation in the housing on an offset parallel axis relative to the main rotor axis.A blade seal can comprise two generally part-cylindrical shaped seals which fit in a substantially cylindrical seating in the rotor, with the blade being positioned between the two part-cylindrical seals.An engine or other system can include a plurality of limited-radial-extension seals mounted transversely around the exterior surface of the slotted rotor. The limited radial extension seals can be proportioned to provide an effective seal between the slotted rotor and the outer perimeter wall of the main rotor cavity over an arc that bounds the location where the radial exterior surface of the slotted rotor and the main rotor peripheral wall are in near tangential contact. Alternatively (or additionally), such seals could be mounted in the peripheral wall.A blade may be mechanically affixed and sealed to the main rotor cavity. The blade may also be mechanically affixed (and possibly sealed to) a main rotor shaft.A combustion chamber can be located in a transfer channel between an output of an inter-rotor compression chamber from one main/slotted rotor pair and an intake port of an inter-rotor combustion gas expansion chamber (or power chamber) of a second main/slotted rotor pair. The transfer channel can have a check valve (or other one way valve) located near the output of the compression chamber. In some embodiments, the combustion chamber is in a rotary valve in the transfer channel between the output of the compression chamber and the intake of the combustion gas expansion chamber.In some embodiments, an inter-rotor combustion chamber is located in the space defined by the interior surface of a main rotor cavity and the exterior surface of the slotted rotor (e.g., chambers702,1702). In these and other embodiments, a fuel/air mixture can be transferred into an inter-rotor compression chamber (e.g., chambers similar to chambers601,1601) from a carburetor located upstream of the intake/compression main/slotted rotor pair. In other embodiments, fuel is injected into an inter-rotor compression chamber by a fuel injector. In still other embodiments, fuel is injected by a fuel injector into the transfer channel (or into a rotary valve or rotary cylinder compression valve in the transfer channel) between the output of the inter-rotor compression chamber and the intake port of the inter-rotor expansion chamber.In some embodiments, fuel is injected by a fuel injector into an inter-rotor space defined by the interior surface of the main rotor cavity and the exterior surface of the slotted rotor in the expansion/exhaust main/slotted rotor pair.Other embodiments include engines with multiple fuel injection locations and/or multiple ignition locations, as well as embodiments in which combustion, once initiated by an ignition source, is self-sustaining.An engine according to some embodiments may include additional combustion gas expanders in communication with the power chamber exhaust port to drive an additional compression chamber that serves as a positive displacement turbocharger to provide pressurized intake air to the engine compression chamber.An engine according to some embodiments may include one or more additional blades mounted concentrically around the exterior surface of the main rotor axle or hub. The additional blades may extend through transverse slots in the slotted rotor and extend to the interior surface of the main rotor. The additional blades can be pivotally attached (e.g., by hinge fittings) to the main rotor axel or hub with seals in blade ends and side slots biased by springs, fluid pressure, centrifugal force, or other means to maintain sealed contact with the interior surfaces of the main rotor cavity.An engine according to some embodiments may include one or more additional blades mounted transversely around the interior surface of the main rotor cavity. The additional blades may extend through transverse slots in the slotted rotor, or terminate in transverse slots in the slotted rotor. The additional blades may be pivotally attached (e.g., by hinge fittings) to the interior perimeter surface of the main rotor cavity, with seals in vane ends and side slots to maintain sealed contact with other interior surfaces of the main rotor cavity.An engine according to some embodiments may include an intake port for the induction of the air or a fuel/air mixture into an inter-rotor compression chamber and an exhaust transfer tube and port for transferring compressed air or fuel/air mixture through the transfer tube into the power (combustion products expansion) inter-rotor chamber. The transfer tube could contain a check valve (ball check valve, foil check valve, reed check valve, leaf check valve, dual plate check valve, swing check valve, lift check valve, etc.), a rotary valve, a rotary cylinder compression valve, and the like. The transfer tube and valve can also house a fuel injector and ignition source.An engine according to some embodiments can include an always-open intake port for the induction of air or fuel/air mixture into an inter-rotor compression chamber and an always-open exhaust port for the exhaust of combustion products (gas) from an inter-rotor exhaust chamber.An engine according to some embodiments can be configured for discharge of air or fuel/air mixture into a manifold, ahead of the blade in an inter-rotor compression chamber, and the further transfer into the space behind the blade in an inter-rotor power (expansion) chamber, when low friction gas seals in the housing (e.g., within +45 and −45 degrees of the rotors' near contact line) are aligned with openings in the sides of the main and/or slotted rotors during each rotation of the rotors.Embodiments include engines and other systems that are air or liquid cooled.Embodiments include engines and other systems in which the rotation of the main rotor and the slotted rotor at the same rotational velocity (rpm) is synchronized by the sliding contact between the blade and the blade seals in the slot in the slotted rotor. Embodiments also include engines and other systems in which rotation of the main rotor and the slotted rotor at the same rotational velocity (rpm) is synchronized by gears, belts, rods, hinges, etc.Embodiments include engines and other systems in which certain load bearing surfaces include one or more of (i) a hard material coating based on one of borides, carbides and nitrides, (ii) a super-hard steel, (iii) a self-lubricating material, and (iv) a diamond-like carbon coating.Embodiments include engines and other systems in which at least one of the load bearing surfaces includes a low friction diamond-like carbon coating.Embodiments include oil lubricated, fuel lubricated and un-lubricated engines.Embodiments include engines configured to use one or more of the following as fuel: liquefied petroleum gas, bio-diesel, butanol, natural gas, biogas, methanol, Fischer-Tropsch fuel, ethanol, n-pentene, hexane, n-heptane, isooctane, and hydrogen.Embodiments further include fuel-lubricated engines wherein an additive to the fuel includes one or more of molybdenum disulfide, graphite, soybean derived oil, canola oil, polytetrafloeraethylene (PTFE), zinc dialkyldithiophosphate, polyalphaolefin, ashless fatty-ester, polybutenyl succinimide, ashless aliphatic-amine, dibasic organic esters, and mineral oil.In some embodiments that include multiple main and slotted rotor pairs, all of the main rotors need not turn about axes that coincide with one another, and all of the slotted rotors need not rotate about coincident axes. For example one main/slotted rotor pair may include a first shaft coupled to the slotted rotor of the first rotor pair. A second slotted rotor pair may include a second shaft coupled to the slotted rotor of the second rotor pair. The first and second shafts may turn about axes that are not coincident, and which may not even be parallel. The first and second shafts could be coupled by gears or mechanical elements configured to transfer rotating motion.In some embodiments, slotted rotors could be linked in a manner similar to that by which rotors1001and1003are connected (e.g., a flange attached to each of the two slotted rotors.Various types of bearings can be used to rotatably support shafts, rotors and other rotating members in various embodiments. Such bearing types include, e.g., ball bearings, roller bearings, tapered roller bearings, fluid bearings, air bearings, foil air bearings, magnet bearings, and the like.

The foregoing description of embodiments has been presented for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit embodiments to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments. The embodiments discussed herein were chosen and described in order to explain the principles and the nature of various embodiments and their practical application to enable one skilled in the art to utilize the present invention in various embodiments and with various modifications as are suited to the particular use contemplated. All embodiments need not necessarily achieve all objects or advantages identified above. Any and all permutations of various features described herein are within the scope of the invention. As used herein, two components are “in fluid communication” if gas or other fluid can flow from one component to another. Such flow may be by way of one or more intermediate (and not specifically mentioned) other components. Such flow may or may not be selectively interruptible (e.g., with a valve) or metered.