2. Description of the Prior Art Rotary engines are known. They are primarily of the Wankel type such as that shown in

U. S. Patent 2,988,065 granted in June of 1961 to Felix Wankel et al. Typically, such engines use the Otto cycle whereby a fuel-air mixture is drawn into a cavity in an outer body by the relative rotation of an inner body, the fuel-air mixture is compressed in a working chamber, the mixture is ignited in the working chamber, and the rapid expansion of the products of combustion in the working chamber drives the inner body around the inner cavity of the outer body, thus generating usable power.

A problem with the Wankel-type engine has been the loss of pressure between adjacent working chambers occasioned by the very high pressures

generated at the beginning of the expansion cycle due to the firing of the fuel/air mixture at the beginning of the expansion cycle and the difficulty in maintaining a pressure seal between each of the inner body apexes and the inner periphery of the epitrochoidal surface of the outer body cavity. These problems have greatly limited the effectiveness and general acceptance of the Wankel-type engine to the present date. A general discussion of the inadequacies and problems suffered by Wankel-type engines and other rotary engines is found i U. S. Patent 4,286,555, granted in September of 1981 to Williams at column 1, paragraph beginning on line 11. In a typical open Brayton cycle engine, air is compressed, fed into a combustor where fuel is injected, the resulting expanding working fluid directed to a turbine where the working fluid energy is converted to rotary motion of the turbine rotor, and the products of combustion are discharged from the turbine.

In a typical closed Brayton cycle engine, a working fluid such as a gas is compressed in a compressor and fed to a heat exchanger where heat energy is added to that fluid, the fluid being used in a closed loop to drive the turbine, the "spent" fluid leaving the turbine and being returned to a second heat exchanger where the remaining heat is extracted from it, and the working fluid is returned to the compressor.

BRIEF SUMMARY OF THE INVENTION A rotary engine utilizes a working fluid and has a cycle which includes the four strokes of

intake, compression, expansion and exhaust. The engine includes an outer body having spaced end walls and a peripheral wall interconnecting the end walls to define, between the end walls, a cavity having an axis along which the end walls are spaced. The inner surface of the peripheral wall has basically the profile of a multi-lobed epitrochoid with its lobes being spaced circumferentially around the outer body cavity axis. This causes the inner surface of the peripheral wall to be partially defined by a plurality of vertex portions, one at each intersection of each pair of lobes.

The engine also includes an inner body received within the outer body cavity and supported for relative movement with respect to the outer body with the axis of the inner body being laterally spaced from, but parallel to, the axis of the outer body cavity.

The inner body has axially-spaced end faces disposed adjacent to and in substantially sealing relationship with respect to the end walls of the outer body. The inner body has an outer peripheral surface partially defined by a plurality of circumferentially spaced apex portions, there being one more apex portion than there are vertex portions of the outer body peripheral wall inner surface.

Each apex portion of the inner body has its radially outermost edge disposed substantially at the outer body peripheral wall inner surface in all relative positions of the inner and outer bodies with respect to each other.

The apex portions have continuous substantially sealing engagement with the outer body

peripheral wall inner surface; and the vertex portions of that outer body peripheral wall are in continuous substantially sealing engagement with the inner body outer peripheral surface. The space between the peripheral surfaces of the outer and inner bodies defines a plurality of working chambers and transient working subchambers which individually vary in volume upon the relative rotation of the inner body with respect to the outer body. Each portion of the outer surface of the inner body between a pair of adjacent apex portions partially defines an adjacent working chamber which extends from one of the apex portions to the other in all relative positions of the two bodies. Each vertex portion of the outer body inner peripheral wall is positioned in turn between the apex portions defining ^• ach working chamber and those portions of the inner body surface of each working chamber between those apex portions and each such vertex portion partially defines a pair of separate transient working subchambers upon relative rotation of the inner body with respect to the outer body.

At least one heat absorbing chamber is positioned adjacent to and separated from the outer body cavity.

Intake passage means having a port opening into the space between the inner and outer body peripheral wall surfaces is provided for consecutively individually inducting a charge of a working fluid into each of the working chambers as the inner body relatively rotates with respect to the outer body in a first direction.

Compression passage means open to the heat absorbing chamber and having a port opening into the space between the inner and outer bodies is provided for consecutively individually discharging each of the working chambers into the heat absorbing chamber as the inner body relatively rotates in the first direction with respect to the outer body.

Expansion passageway means open to the heat absorbing chamber having a port opening into the space between the bodies is provided for consecutively individually conducting an expanding charge of working fluid from the heat absorbing chamber into each of the working chambers as the inner body relatively rotates with respect to the outer body in the first direction.

Exhaust passage means having a port opening into the space between the bodies is provided for consecutively individually exhausting each of the working chambers as the inner body relatively rotates in the first direction with respect to the outer body.

Means is provided for coupling the inner and outer bodies together. In the invention as shown, the outer body is stationary and the inner body performs a planetary movement with respect to the outer body in accordance with the shapes of the inner and outer bodies and in accordance with the design, of the coupling means. However, it is within the spirit of the invention and the scope of the claims which follow that the inner and outer bodies can move with respect to each other whether or not the outer body is stationary.

In the rotary engines as shown herein, there are two lobes to each outer body epitrochoid, and there are three apex portions to each inner body.

However, there can be more epitrochoid lobes and more apex portions. The number of apex portions will be one more than the number of lobes and vertex portions.

In an open Brayton cycle engine as disclosed herein, the primary working fluid can be air, oxygen or other combustion supporting gas, or a fuel/air mixture

In the closed Brayton cycle engines disclosed, the working fluid can be any one of a number of suitable substances, a monatomic gas such as helium being a preferred one of such substances.

Applicant and those in privity with him are aware of no closer prior art than that set out above; and they are aware of no prior art which anticipates the claims herein. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional view through the axis of an outer body cavity of an open cycle first form of rotary engine of the invention in which the inner periphery of an outer body or housing has the shape of a two-lobed epitrochoid, and in which an inner body or rotor is rotatably mounted in the outer body, is shaped as the approximate inner envelope of the inner periphery of the outer body and has three apex portions; FIG. 2 is a vertical sectional view of the engine of FIG. 1 taken on the line 2—2 in that figure, and showing the inner body in a first position with respect to the outer body and

disclosing a heat absorbing chamber as part of the engine;

FIG. 3 is a vertical sectional view of the engine of FIGS. 1 and 2 on a reduced scale but also taken on the line 2—2 in FIG. 1 with the heat absorbing chamber removed therefrom, and showing the inner body in a second position rotated 30° in counterclockwise direction from its first position;

FIG. 4 is another vertical sectional view as in FIG. 3 but with the inner body rotated 30° in counterclockwise ^' direction from its position as seen in FIG. 3;

FIG. 5 is also a vertical sectional view as in FIGS. 3 and 4 but showing the rotor as having moved 30° in counterclockwise rotation from the position as seen in FIG. 4;

FIG. 6 is a vertical sectional view through the axis of an outer body cavity of a closed cycle second form of rotary engine of the invention taken as on the line 6—6 in FIG. 7 and in which the inner periphery of an outer body or housing has the shape of a two-lobed epitrochoid, and in which an inner body or rotor is rotatably mounted in the outer body, is shaped as the approximate inner envelope of the inner periphery of the outer body and has three apex portions;

FIG. 7 is a vertical sectional view of the engine of the second form of the invention taken on the line 7—7 in FIG. 6 and showing a heat exchanger and a heat absorbing chamber as part of the engine;

FIG. 8 is a vertical sectional view, taken as if on the lines 8—8 in FIG 10, through the axis of outer body cavities of a closed cycle third form

of rotary engine of the invention, said engine utilizing two outer bodies or housings each providing its own housing cavity in which the inner periphery has the shape of a two-lobed epitrochoid, and utilizing two inner bodies or rotors each rotatably mounted in one of said outer bodies, each shaped as the approximate inner envelope of the inner periphery of its outer body and each inner body having three apex portions; FIG. 9 is a horizontal top view partially in plan and partially in section taken on the line 9—9 in FIG. 8 showing one actual physical positioning .of the two outer bodies and the two inner bodies with respect to each other and showing the relative positioning of two heat exchangers and a heat absorbing chamber forming a part of the engine; and

FIG. 10 is a partially schematic representation of the engine of FIGS. 8 and 9 showing the relative congruent positioning of the actually axially concentric first and second outer bodies and the offset relationship of the inner bodies therein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OPEN BRAYTON CYCLE ROTARY ENGINE As seen in FIGS. 1 through 5, an open cycle rotary external combustion engine 10 made according to a first form of the invention uses air and the products of combustion of fuel with an appropriate amount of air as a working fluid. Engine 10 includes a stationary housing or outer body 12 provided with an outer body cavity 14 into which is received a rotor or inner body 16 which is supported for relative movement with respect to the outer body. The outer body 12, the inner body 16 and all of the

elements of and inside of the outer body constitute a mutually rotating engine body assembly 17.

In this first form of the invention, the housing or outer body 12 includes a pair of spaced end walls 18 and 19 and a peripheral wall 20 bounded by an inner peripheral surface 24. The end walls 18 and 19 and inner peripheral wall surface 24 define the outer body cavity 14. This cavity has an axis 22 along which the end walls 18 and 19 are spaced. Inner peripheral wall surface 24 of the peripheral outer body wall 20 has basically the profile of a two-lobed epitrochoid with lobes 26 and 27 being spaced circumferentially around the axis 22. This inner peripheral surface 24 of wall 20 is partially defined by a pair of vertex portions 28 and 29, one at each intersection of the lobes 26 and 27 with each other.

An output power shaft 30 is journaled in a ball bearing 32 supported in end wall 18 and in a ball bearing 34 suitably supported in an opening 35 provided in end wall 19. An intermediate portion of the shaft 30 mounts an integral eccentric 36 having an axis 37 parallel to and offset from axis 22. The rotor or inner body 16 is rotatably supported on this eccentric through the instrumentality of a bushing 38.

Inner body 16 is provided with an internally toothed gear 40 that is in mesh with a spur gear 42 which extends integrally outwardly from the end wall 18 in surrounding, supporting relation to an outer race of bearing 32.

As seen in FIG. 1, the end faces of the inner body 16 are run sufficiently close to the faces

of the end walls 18 and 19 of the outer body so that no significant pressure is lost between these adjacent faces when the engine is running. This can be achieved by holding close tolerances or by any one of a number of preferred or usual techniques (such as disclosed in U.S. Patents 2,880,045; 3,193,188 and 4,032,268), this feature forming no part of the present invention per se.

Inner body or rotor 16, in addition to the aforementioned inner body end walls, has three apex portions 46, 47 and 48 and is defined by an outer peripheral surface 44. Surface 44 has a profile approximating the inner envelope of the projections of the two-lobed epitrochoid of the inner surface 24 on a transverse plane integral with the inner body in all successive positions of the two bodies as they undergo relative movement. This shape or profile is determined by the eccentricity or offset of their axes and by the number of outer body lobes (two) and the number of inner body apexes (three). This inner envelope (determining the shape of the outer peripheral inner body surface 44) is the maximum permissible outline of the inner body beyond which interference between the inner body and the peripheral wall of the epitrochoidal cavity will occur. For brevity, this inner envelope is herein sometimes referred to as the inner envelope of the epitrochoid.

The relative movement between the inner body and the outer body is determined by the number of apex portions relative to the number of lobe-defining portions. In this instance, for each complete revolution of the inner body 16 about its own axis,

- li ¬ the shaft 30 turns .three revolutions in the same direction. The dimension or teeth ratio of the gears 40 and 42 permanently maintains this speed ratio.

The space between the inner peripheral surface 24 of the wall 20 of the stationary housing or outer body 12 on the one hand and the outer peripheral surface 44 of the inner body 16 on the other is divided into three working chambers of variable volume. This space between first apex portion 46 and second apex portion 47 is designated as a first working chamber 50; the space between second apex portion 47 and third apex portion 48 is designated as a second working chamber 54; and the space between third apex portion 48 and first apex portion 46 is designated as third working chamber 58.

With the inner body 16 positioned with respect to the outer body 12 as seen in FIG. 2, the first working chamber 50 has been divided into a first working subcha ber 51 between second apex portion 47 and first vertex portion 28, and a second subchamber 52 bounded by first vertex portion 28 and first apex portion 46.

As seen in FIG. 2, first subchamber 51 of first working chamber 50 is open to an intake port 61 which extends through the peripheral wall 20 of the outer body 12 to the atmosphere preferably through any usual or preferred air cleaner (not shown). Second working chamber 54 is open to a compression port 62 through the wall 20 and through a one-way check valve 66 to a heat absorbing chamber 64.

In the form of the invention as shown, a fuel injector 68 extends into the heat absorbing chamber 64 so that the heat absorbing chamber/fuel

injector combination can serve as a combustion chamber or combustor 70 in this form of the invention.

Still referring to FIG. 2, heat absorbing chamber 64 is open through an expansion port 72 in wall 20 of the outer body 12 to third working chamber 58.

Second working subchamber 52, as seen in FIG. 2, is open through an exhaust port 74 provided through wall 20. This exhaust port can discharge into any usual or preferred exhaust pipe, muffler, heat exchange unit or the like (not shown).

The configuration of the outer and inner bodies is such that the three apexes of the inner body are, in all relative positions of the bodies with respect to each other, close enough to the inner peripheral surface 24 of the outer body so that no significant pressure is lost from one working chamber to the next as the engine operates. This can be done with radial seals of any usual or preferred construction (see U. S. Patents 2,800,045; 3,193,188; and 4,032,268, for example), or by maintaining strict tolerances to hold the apexes as close to the surface 24 as possible without actual physical contact.

Similarly, theoretically and actually, the vertexes or vertex portions 28 and 29 at the intersections of the lobes 26 and 27 of the inner peripheral surface 24 of wall 20 are in extremely close proximity to the outer surface 44 of inner body 16. This relationship will be such that no significant pressure is lost between adjacent working chambers and working subchambers as peripheral surfaces of the inner body 16 pass the vertex portions 28 and 29. This may be achieved several

ways; for example, by maintaining close tolerances, or by mounting flexible seals 76 and 77 into the vertex portions 28 and 29, respectively, as those illustrated. By mounting these seals at angles substantially as shown, pressure transfer can be minimized and chatter can be avoided or minimized. OPERATION OF FIRST FORM OF ROTARY ENGINE

The operation and function of a typical working chamber and its subchambers will be set out in terms of the disclosures of FIGS. 2 through 5. As the inner body 16 moves in counterclockwise direction from position as seen in FIG. 2 to that of FIG. 3, of FIG. 4, FIG. 5 and back to that of FIG. 2, the typical working chamber will be seen serially as first working chamber 50, second working chamber 54, third working chamber 58 and back to first working chamber 50.

With the rotor or inner body 16 rotating about the axis 37 of the eccentric 36 in counter- clockwise direction as seen in FIGS. 2 through 5, and revolving about the axis 22 of the outer body cavity 14 and the output power shaft 30, and as the inner body 16 reaches the position as seen in FIG. 2, a typical first working subchamber (first working subchamber 51) of a typical working chamber (first working chamber 50) will be expanding in volume to draw air through the intake port 61, while the volume of a typical second working subchamber (second working subchamber 52 of the first working chamber 50) will be decreasing and forcing its contents out through the exhaust port 74 to the atmosphere through any ^" usual or preferred exhaust mechanism (not shown) .

As the inner body rotates one-twelfth of a turn or through 30°, it will reach position as seen in FIG. 3 where first working subchamber 51 is greatly enlarged and second working subchamber 52 has virtually disappeared. After another rotation of 30° or another one-twelfth of a turn, and as seen in FIG. 4, the first and second working subchambers have disappeared into the typical working chamber (chamber 50) which has almost reached its maximum volume of intake air.

After another rotation of one-twelfth of a turn to position as seen in FIG. 5, the volume of the typical working chamber (chamber 50) is at its maximum and the chamber is filled with fresh intake air. The first apex portion 46 of the inner body 16 has about sealed chamber 50 from intake port 61 and second apex portion 47 is about to open chamber 50 to compression port 62.

To follow the sequence, after rotation of the inner body 16 through another one-twelfth turn, the typical working chamber has assumed the position of the second working chamber 54 back in FIG. 2. The typical working chamber (chamber 54) is now decreasing in volume and the intake air is being forced out through the compression port 62 and through one-way valve 66.

^• After another rotation of one-twelfth of a turn, the typical chamber (chamber 54) reaches the position as seen in FIG. 3, where the air in the chamber has been compressed further and more of it has been forced through the compression port 62 and valve 66. At this point, vertex portion 29 of the outer body cavity 14 has now divided the typical

working chamber (second working chamber 54) into a third working subchamber 55 and a fourth working subchamber 56.

Further rotation for the next one-twelfth of a turn to position as seen in FIG. 4 causes virtually all of the intake air in the typical working chamber (second working chamber 54) and specifically in the fourth working subchamber 56 to be expelled into the compression port 62 and, consequently, into the heat absorbing chamber 64, here shown as a combustion chamber or combustor 70. Here heat energy is added so that air ^' and the combustion products of the ignited fuel with the air now constitute the working fluid. This working fluid expands through expansion port 72 and into third working subchamber 55 where expansion continues. This expansion of the working substance in third working subchamber 55 forces the inner body 16 in counterclockwise direction from the position of the typical working chamber (second working chamber 54) as seen in FIG. 4 toward and beyond the next position of rotation as seen in FIG. 5.

Expansion of the working fluid in third working subchamber 55 continues to force rotation of inner body 16 from position as seen in FIG. 5 to the position as seen in FIG. 2 where the third and fourth working subchambers are eliminated and the typical working chamber assumes the position of the third working chamber 58. With expansion in this typical working chamber (third working chamber 58) still continuing, the inner body 16 moves to position as seen in FIG. 3 where the typical working chamber (third working chamber 58) is about cut off from the

expansion port 72 by movement of third apex portion 48 at about the same time that the working chamber is opened to the exhaust port 74 by passage of the first apex portion 46 of the inner body. As the inner body continues to rotate to move the typical chamber (chamber 58) from the position as seen in FIG. 3 to the position as seen in FIG. 4, the now fully expanded contents of the typical chamber are being discharged through exhaust port 74 into the atmosphere.

As rotation continues, and as the inner body 16 moves from the position as seen in FIG. 4 to the position as seen in FIG. 5, the first and second working subchambers 51 and 52 are being reestablished, the remainder of the exhaust gases are forced out of the second working subchamber 52 of working chamber (chamber 58) through the exhaust port 74, and the first working subchamber 51 is again expanding in volume to draw in fresh air. It is to be understood that every time one of the working chambers reaches the point where a third working subchamber such as 55 is in alignment with expansion port 72, the energy in the working fluid is exerted within that subchamber to the end that there are three working "strokes" forcing the inner body 16 to rotate with every complete rotation of that body.

CLOSED BRAYTON CYCLE ROTARY ENGINE As seen in FIGS. 6 and 7, a closed Brayton cycle rotary engine 110 made according to a second form of the invention uses helium in a closed hydraulic loop as a working fluid. Engine 110

includes a stationary housing or outer body 112 provided with an outer body cavity 114 into which is received a rotor or inner body 116 which is supported for relative movement with respect to the outer body. In this form of the invention, as in the first form of the invention, the outer body 112 includes a pair of spaced end walls 118 and 119 and a peripheral wall 120 bounded by an inner peripheral surface 124. The end walls 118 and 119 and the inner peripheral wall surface 124 define the outer body cavity 114. This cavity has an axis 122 along which the end walls 118 and 119 are spaced. Inner peripheral wall surface 124 has basically the profile of a two-lobed epitrochoid with lobes 126 and 127 being spaced circumferentially around the axis 122. The inner peripheral surface 124 of the wall 120 is partially defined by a pair of vertex portions 128 and 129, one at each intersection of the lobes 126 and 127 with each other. A power output shaft 130 is journaled in a ball bearing 132 supported in end wall 118 and in a ball bearing 134 suitably supported in an opening 135 provided in end wall 119. An intermediate portion of the shaft 130 mounts an integral eccentric 136 having an axis 137 parallel to and offset from axis 122. The rotor or inner body 116 is rotatably supported on the eccentric through the instrumentality of a bushing 138.

Inner body 116 is provided with an internally toothed gear 140 that is in mesh with a spur gear 142 which extends integrally outwardly from the end wall 118 in surrounding, supporting relation to an outer race of bearing 132.

As is the case with the first forms of the invention, the end faces of the inner body 116 are run sufficiently close to the faces of the end walls

118 and 119 of the outer body so that no significant pressure is lost.

Inner body or rotor 116, in addition to the aforementioned inner body end walls, has three apex portions 146, 147 and 148 and is partially defined by an outer peripheral surface 144. As was the case in connection with the first form of the invention, the profile of this outer peripheral inner body surface 144 is equivalent to the inner envelope of the epitrochoid.

The space between the outer wall inner peripheral surface 124 of the outer body 112 on the one hand and the outer peripheral surface 144 of the inner body 116 on the other is divided into three working chambers of variable volume, namely, first working chamber 150, second working chamber 154 and third working chamber 158.

With inner body 116 positioned with respect to outer body 112 as seen in FIG. 7 (comparable with the positioning in FIG. 5 of the first form of the invention) , the third working chamber 158 has been divided into a first working subchamber 151 between the first apex portion 146 and the first vertex portion 128, and a second subchamber 152 bounded by the first vertex portion 128 and the third apex portion 148. The second working chamber 154 has been divided into a third working subchamber 155 between third apex portion 148 and second vertex portion 129, and a fourth subchamber 156 bounded by second vertex portion 129 and second apex portion 147.

Many changes can be made with respect to the structure inside of the outer body or stationary housing 112 within the spirit of the invention and the scope of the claims which follow. However, an

05 intake port 161, a compression port 162, an expansion port 172 and an exhaust port 174 all extend through the stationary housing of outer body 112 in the same manner as similar parts shown and described in the first form of the invention. For the purpose of the

10 understanding of this second form of the invention as shown in FIGS. ^' 6 and 7, the operation of the parts including and within the outer body 112 can be considered identical with the operation of the parts bearing equivalent but two digit numbers as explained

15 in connection with the first form of the invention.

The structures which differentiate the closed Brayton cycle engine of the second form of the invention from the open Brayton cycle engine of the first form of the invention include a first heat

20 exchanger or heat absorbing chamber 163 consisting of an outer shell 165, an upper plate 180 and a lower plate 181 dividing the space inside of the shell 165 into an upper plenum 182, a lower plenum 183 and a heat absorbing region 184. A plurality of parallel,

25. vertical, spaced-apart flue pipes 185 are open through the upper and lower, plenum-defining plates 180 and 181 and extend through the heat absorbing region 184. A lower fuel/air receiving port 167 is open through shell 165 to the lower plenum 183; and

30 an upper combustion products discharge port 170 is open from the upper plenum 182.

A combustor or combustion chamber 171 is open to fuel/air receiving port 167 and is provided

with a combustion air inlet port 173. A fuel injector 169 in the combustion chamber 171 provides fuel from an outside source not specifically shown.

Although delineated in its generic form as a heat absorbing chamber 163, this particular chamber is, in reality, of course, but one of a number of different forms of heat exchanger which would work satisfactorily in connection with this form of the invention. In order to provide for closed loop operation, a second heat exchanger 187 is provided. This second heat exchanger includes an outer shell 189 defining a heat exchange region 191, and a continous double spiral-wound combustion air heating coil 192 open through outer shell 189 to an upper combustion air intake port 193 and open through the shell to a lower heated combustion air delivery port 195.

The outer shell 189 is otherwise imperforate and provides, with appropriate baffles, a working fluid passageway 197 open from the exhaust port 174 to the intake port 161 provided by the outer body 112. The arrangement is such that the helium or other suitable heated working fluid being exhausted from the outer body 112 can have the remaining heat removed therefrom bringing ^' it to its original state before being drawn back into that outer body through the intake port 161.

To make use of the heat extracted from the working fluid, a heated combustion air conduit 198 extends from the heated combustion -air delivery port 195 to combustion air inlet port 173 of the combustion chamber or combustor 171.

A suitable compression passageway is provided through the shell 165 as an extension of the opening in compression port 162. A one-way valve 166 is provided in that passageway to allow passage of working fluid from the port 162 into the heat absorbing region 184 of the heat absorbing chamber 163 but to prevent return of fluid or loss of pressure in the opposite direction.

An expansion passageway is provided through shell 165 from the heat absorbing region 184 to expansion port 172 in the outer body 112, and suitable baffles (not shown in detail) are provided to maximize the heat exchange between combustion products flowing through the flue pipes 185 and the working fluid within the heat absorbing chamber 163. OPERATION OF SECOND FORM OF ROTARY ENGINE

The operation of the engine as far as the rotation of the inner body with respect to the outer body is concerned and as far as the intake of working fluid through the intake port, the discharge of that fluid through the compression port, the delivery of the expanding working fluid through the expansion port and the discharge of that fluid through the exhaust port is concerned, is substantially identical to that explained in connection with the first open cycle form of the invention. Identical parts are identically numbered except that the parts in FIGS. 6 and 7 carry numbers which are numbered one hundred higher than their counterparts in FIGS. 1 through 5. The outer body cavity 114, the working fluid passageway 197 in the second heat exchanger 187, and the heat absorbing region 184 of the heat absorbing chamber 163 are charged with a suitable working

fluid, for example, a monatomic gas such as helium. Flow of combustion air through the combustion air heating coil 192, conduit 198, combustor 171, flue pipes 185 and out of upper combustion product discharge port 170 is induced by a fan or any other usual or preferred means (not shown).

Ignition is initiated in the combustor 171. The rotor or inner body 116 will then be driven to rotate and revolve with respect to the outer body 112 in the manner described in connection with the first form of the invention. The working fluid will initially be drawn in through the intake port 161, compressed and discharged through the compression port 162 and one-way valve 166 into the heat absorbing chamber 163 where it will take on the heat energy from its contact with the heated flue pipes 185. The working fluid will then be caused to expand and leave the heat absorbing chamber 163 through the expansion port 172 where it will force . the inner body 116 to rotate in counterclockwise direction as seen in FIG. 7. When spent, this working fluid will be discharged through exhaust port 174 in the manner set out in connection with the first form of the invention. The remaining heat energy will then be removed as the working fluid passes over and around the combustion air heating coil 192 and imparts heat to those coils.

An extensive discussion of the closed Brayton cycle in conjunction with the operation of turbines is set out in Fundamentals of Classical Thermodynamics, Second Edition, SI Version, by Van Wylen and Sonntag, published by John Wiley and Sons, Inc., pp.335-342.

From the foregoing, it is evident that the heat absorbing chamber can supply heat to the working fluid in any one of a number of ways. Specifically, any kind of liquid, solid or gaseous fuel can be used to supply heat energy to a heat absorbing chamber. Solar energy can also be employed for this purpose.

The efficiencies of this cycle of operation include utilization of the normally "wasted" heat leaving the exhaust port 174 to- preheat the combustion air and so increase the efficiency of the operating cycle. Like in many other engines, the heat from the upper combustion product discharge port 170 is also available for auxiliary heating.

CLOSED BRAYTON CYCLE TWO-STAGE ROTARY ENGINE During the compression of the working fluid from the time it fills a working chamber until the time it is expelled through the compression port, some properties of a monatomic gas, such as helium for example, are undesirable, such as the difficulty in compressing without excessive temperature rise. These same properties make the use of such a gas desirable during the expansion phase. For this reason, an intercooler and two-stage compression may be used with significant improvement in performance. Such a multi-stage closed Brayton cycle rotary engine, made in accordance with the third form of the invention, is illustrated in FIGS. 8 through 10.

In these figures, a closed Brayton cycle, multi-stage rotary engine 210 includes a first stationary housing or outer body 212 provided with a first outer body cavity 214 into which is received a first rotor or inner body 216 which is supported for relative movement with respect to the outer body.

In this third form of the invention, the first housing or outer body 212 includes a pair of spaced end walls 218 and 219 and a peripheral wall

220 bounded by an inner peripheral surface 224. The end walls 218 and 219 and the inner peripheral wall surface 224 define the outer body cavity 214. This first outer body cavity has an axis 222 along which the end walls 218 and 219 are spaced. Inner peripheral wall surface 224 of the peripheral outer body wall 220 has basically the profile of a two-lobed epitrochoid with lobes 226 and 227 being spaced circumferentially around the axis 222. This inner peripheral surface 224 of the wall 220 is partially defined by a pair of vertex portions 228 and 229, one at each intersection of the lobes 226 and 227 with each other.

An output power shaft 230 is journaled in a ball bearing 232 supported in end wall 218 and in a bearing 234 suitably supported in an opening 235 provided in end wall 219. An intermediate portion of the shaft 230 mounts a first integral eccentric 236 having an axis 237 parallel to and offset from the axis 222. The inner body 216 is rotatably supported on this eccentric through the instrumentality of a bushing 238.

First inner body 216 is provided with an internally toothed gear 240 that is in mesh with a spur gear 242 which extends integrally outwardly from the end wall 218 in surrounding, supporting relation to an outer race of the bearing 232.

As seen in FIGS. 8 and 9,. the end faces of the inner body 216 are run sufficiently close to the

faces of the end walls 218 and 219 of the outer body so that no significant pressure is lost between these adjacent faces when the engine is running.

First inner body or rotor 216, in addition to the aforementioned inner body end walls, has three apex portions 246, 247 and 248 and is defined by an outer peripheral surface 244. Surface 244 has a profile approximating the inner envelope of the epitrochoid. The space between the inner peripheral surface 224 of the wall 220 on the one hand and the outer peripheral surface 244 of the inner body 216 -on the other hand is divided into three working chambers of variable volume. With the first outer and first inner bodies positioned with respect to each other as seen in FIG. 10, (corresponds with FIG. 3 of the first form of the invention), the space between the first apex portion 246 and the second apex portion 247 is designated as a first working chamber 250; the space between second apex portion 247 and third apex portion 248 is designated as a second working chamber 254; and the space between third apex portion 248 and first apex portion 246 is designated as third working chamber 258. With the first inner body 216 positioned with respect to the first outer body 212 as seen in FIG. 10, the first working chamber 250 has been divided into a first working subchamber 251 between second apex portion 247 and the first vertex portion 228 and a second working subchamber 252 bounded by first vertex portion 228 and first apex portion 246.

As also seen in that figure, the second working chamber 254 has been divided into a third

working subchamber 255 between the third apex portion 248 and the second vertex portion 229 and a fourth working subchamber 256 bounded by second vertex portion 229 and second apex portion 247. In the form of the invention as shown, the first stationary housing or first outer body 212 also provides what is the equivalent of a second stationary housing or outer body. These outer bodies could be separated, but for simplicity of description, the portion of the first stationary housing or outer body 212 to the right in FIGS. 8 and 10 and on top in FIG. 9 will be referred to as a second stationary housing or second outer body 312. Thus, this second outer body 312 is provided with a second outer body cavity 314 into which is received a second rotor or inner body 316 which is supported for relative movement with respect to the second outer body 312.

The outer body 312 includes a peripheral wall 320 bounded by an inner peripheral surface 324, and an end wall 318 which is parallel to and spaced from the end wall 219 which the second outer body 312 shares with the first outer body 212. The end walls 318 and 219 and a peripheral surface 324 of the inner peripheral wall 320 define the second outer body cavity 314. This second outer body cavity has an axis 322 (coincident with axis 222) along which the- end walls 318 and 219 are spaced. Inner peripheral wall surface 324 of the peripheral outer body wall 320 has basically the profile of a two-lobe epitrochoid with lobes 326 and 327 being spaced circumferentially around the axis 322. This inner peripheral surface 324 of the wall 320 is partially

defined by a pair of vertex portions 328 and 329, one at each intersection of the lobes 326 and 327 with each other.

In addition to being journalled in ball bearing 232 and in a bearing 234, the output power shaft 230 is also journalled in a ball bearing 332 which is suitably supported in an opening 335 provided in end wall 318. An intermediate portion of shaft 230 . mounts a second integral eccentric 336 having an axis 337 parallel to and offset from the axis 222/322. The second inner body 316 is rotatably supported on this eccentric through the instrumentality of a bushing 338.

Second inner body 316 is provided with an internally toothed gear 340 that is in mesh with a spur gear 342 which extends integrally outwardly from end wall 318 in surrounding, supporting relation to an outer race of the bearing 332.

Second inner body 316 has three apex portions 346, 347 and 348 and is defined by an outer peripheral surface 344. Surface 344 has a profile approximating the inner envelope of the epitrochoid.

The space between the inner peripheral surface 324 of the wall 320 on the one hand and the outer peripheral surface 344 of the inner body 316 on the other hand is divided into three working chambers of variable volume. With the second outer and second inner bodies positioned with respect to each other as seen in FIG. 10 (corresponds with FIGS. 5 and 7 of the first and second forms of the invention), the space between the first apex portion 346 and the second apex portion 347 is designated as a first working chamber 350; the space between second apex

portion 347 and third apex portion 348 is designated as a second working chamber 354; and the space between third apex portion 348 and first apex portion 346 is designated as third working chamber 358. With the second inner body 316 positioned with respect to the second outer body 312 as seen in FIG. 10, the third working chamber 358 has been divided into a first working subchamber 351 between first apex portion 346 and first vertex portion 328 and a second working subchamber 352 bounded by first vertex portion 328 and third apex portion 348.

Also as seen in that figure, the second working chamber 354 has been divided into a third working subchamber 355 between the third apex portion 348 and the second vertex portion 329 and a fourth -working subchamber 356 bounded by second vertex portion 329 and second apex portion 347.

Intake ports 261 and 361, compression ports 262 and 362, expansion ports 272 and 372 and exhaust ports 274 and 374 extend through the inner bodies 212 and 312 in the same manner as similar parts shown and described in connection with the first two forms of the invention. For the purpose of understanding this third form of the invention as shown in FIGS. 8, 9 and 10, the operation of the parts including and within the outer bodies 212 and 312 can be considered identical with the operation of the parts bearing equivalent but lower numbers as explained in connection with the first two forms of the invention. A heat absorbing chamber 263 consists of an outer shell 265, an upper plate 280- and a lower plate 281 dividing the space inside of shell 265 into an upper plenum 282, a lower plenum 283 and a heat

absorbing region 284. A plurality of parallel, vertical, spaced-apart flue pipes 285 are open through the upper and lower plates 280 and 281 and extend through the heat absorbing region 284. A lower fuel/air receiving port 267 is open through shell 265 to the lower plenum 283; and an upper combustion products discharge port 270 is open from the upper plenum 282.

A combustor or combustion chamber 271- is open to the fuel/air receiving port 267 and is provided with a combustion air inlet port 273. A fuel injector 269 of any usual or preferred construction extends into the combustion chamber 271 to provide fuel from an outside source not specifically shown.

A second heat exchanger 287 includes an outer shell 289 defining a heat exchange region 291, and a continuous double spiral-wound combustion air heating coil 292 open through outer shell 289 to a lower combustion air intake port 294 and open through the shell to an upper combustion air delivery port 296.

The outer shell 289 is otherwise imperforate and provides, with appropriate baffles, a working fluid passageway 297 open from exhaust port 374 through the heat exchange region 291 to the ^* intake port 361 provided by the second outer body 312.

A third heat exchanger or intercooler 387 includes an outer shell 389 defining a heat exchange region 391, and a continuous double spiral-wound combustion air heating coil 392 open through outer shell 389 to a combustion air intake port 393 and

open through the shell to a combustion air delivery port 395.

The outer shell 389 is otherwise imperforate and provides, with appropriate baffles, a working fluid passageway 397 open from compression port 362 of second outer body 312, through heat exchange region 391 of third heat exchanger 387 to intake port 261 provided by the first outer body 212.

An exhaust conduit or passageway 276 extends from exhaust port 274 open through peripheral wall 220 of the first outer body 212 to expansion port 372 open through wall 320 of second inner body 312.

A suitable compression conduit or passageway is provided through the shell 265 of heat absorbing chamber 263 as an extension of the opening in compression port 262 in the first outer body 212. A one-way check valve 266 is provided in that passageway to allow passage of working fluid from the port 262 into the heat absorbing region 284 of the heat absorbing chamber 263 but ^' to prevent return of fluid or loss of pressure in the opposite direction.

An expansion passageway is provided through shell 265 from the heat absorbing region 284 to expansion port 272 in the first outer body 212, and suitable baffles (not shown in great detail) are provided to maximize the heat exchange between the combustion products flowing through the flue pies 285 and the working fluid within the heat absorbing chamber 263. Heated combustion air conduits 398 and 399 extend from combustion air delivery port 395 of the intercooler 387 to combustion air inlet port 273 of the combustor 271, and from upper combustion air

delivery port 296 to combustion air intake port 393, respectively.

OPERATION OF THIRD FORM OF ROTARY ENGINE With the combustor 271 in operation and the amount of fuel supplied by the fuel injector 269 and/or the amount of combustion air supplied to the lower combustion air intake port 294 controlling the energy input to the rotary engine 210, the rotors or inner bodies 216 and 316 will be rotating simultaneously about their axes 237 and 337, respectively, and revolving about the axis 222/322- of the output power shaft 230. This will cause the helium to be drawn from the working fluid passageway 297 of the second heat exchanger 287 through the intake port 361 in the second stationary housing or outer body 312, compressed in each of the working chambers and delivered through the compression port 362 to the working fluid passageway 397 where the heat of compression will be dissipated in the third heat exchanger or intercooler 387 by the passage of the combustion air through the air heating coil 392 in the heat exchange region 391 of the intercooler. The helium leaving working fluid passageway 397 is drawn through the intake port 261 of the first stationary housing or outer body 212, and further compressed by the working chambers each in turn, and delivered through the compression port 262 and past one-way check valve 266 into the heat absorbing region 284 of the heat absorbing chamber 263.

Here the heat energy from the combustor is passed to the working fluid, helium, as the products of combustion pass through flue pipes 285 in the heat

absorbing area, causing the working fluid to expand through the expansion port 272, there to perform work in each such successive working chamber 250, 254 and 258 to cause the output power shaft 230 to rotate on its axis 222.

This forced rotation of shaft 230 represents the useful power output of the engine.

The expanded working fluid is then exhausted from the first outer body 212 through exhaust port 274, exhaust conduit 276 and into expansion port 372 of second outer body 312 where it can again expand, this time successively in working chambers 350, 354 and 358 before being exhausted through exhaust port 374 into the working fluid passageway 297 of the second heat exchanger 287. Here the remaining heat energy and the working fluid will be extracted in the process of initially heating the incoming combustion air through the continuous, spiral, double-wound combustion air heating coil 292 in the heat exchange region 291.

When the working fluid leaves the working fluid passageway 297 to again enter through port 361 of the second outer body 312, it is back to its original pressure and temperature so that the Brayton cycle can be repeated.

During this process, the combustion air has been heated first by the second heat exchanger and then by the intercooler so that the heat energy extracted from the working fluid at these points is returned to the engine in the form of heated combustion air through the combustor and into the heat absorbing region 284 of the heat absorbing chamber 263.

POSSIBLE MODIFICATIONS AND ENHANCEMENTS

A single cavity or "cylinder" engine has been disclosed in connection with the first and second forms of the invention, and a two-stage single external heat absorbing chamber or heat exchanger has been shown in connection with the third form of the invention. Additional power can be developed, and drive shaft or output power shaft balancing problems can be reduced substantially by providing "multi-cylinder" configurations whereby each heat absorbing chamber/drive cavity or "cylinder" is delivering its power to the same output power shaft or drive shaft.

In all forms of the invention shown, the intake, compression, expansion and exhaust passage means is illustrated as extending through the peripheral wall of the outer body. One or more of these passage means can extend through an end wall of the outer body or even through a wall of the inner body. (See U. S. Patent 2,988,065, FIG. 1 and specification, column 6, beginning on line 8 where inner rotor 2 is seen to have internal ducts 28, for example. )

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.