US3895610A

US3895610A - Rotary Nutating engine

Info

Publication number: US3895610A
Application number: US470860A
Authority: US
Inventors: Robert H Wahl
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-05-17
Filing date: 1974-05-17
Publication date: 1975-07-22
Anticipated expiration: 1992-07-22

Abstract

The engine comprises a housing having a spherical chamber containing a pair of segmental-spherical members having confronting recessed operating faces. One member, the stator, is fixed and has in its face a pair of opposed, radially projecting, segmental-conical recesses separated by a pair of curved, segmental-conical ribs, the apices of which lie in a common plane extending diametrally through the stator. The other member, the rotor is journaled in the inner end of a crankshaft which projects into the housing coaxially of the stator, and has in its face three, radially projecting, segmental-conical recesses separated by three-equi-angularly spaced ribs having linear apices, which project radially from the axial centerline of the rotor. The rotor is rotatable about an axis inclined to the crankshaft, and at a different speed than the crankshaft. Therefore, when the crankshaft rotates, nutating rotary motion is imparted to the rotor so that its ribs follow the recessed face of the stator without imparting any reciprocable motion to either. Ports in the stator and/or housing are used to supply fluid or fuel to, and to exhaust compressed fluid from, revolving pockets which are formed by the recesses in the rotor during operation of the engine as either a fluid pump or engine, or as an internal combustion engine.

Description

United States Patent Wahl July 22, 1975 ROTARY NUTATING ENGINE chamber containing a pair of segmental-spherical [76] Inventor: Robert H. wahl, 1747 Creek Rd" members having confronting recessed operating faces. Rochester NY. 14625 One member, the stator, is fixed and has in its face a pair of opposed, radially pro ecting, segmental-conical [22] Filed: May 17, 1974 recesses separated by a pair of curved, segmentalconical ribs, the apices of which lie in a common [21] Appl' 470860 plane extending diametrally through the stator. The other member, the rotor is journaled in the inner end [52] US. Cl l23/8.45; 4] 8/49 of a crankshaft which projects into the housing coaxi- Fozb 53/00 ally of the stator, and has in its face three, radially [58] Field Of Search 123/845; projecting, segmental-conical recesses separated by 4 68 three-equi-angularly spaced ribs having linear apices,

- which project radially from the axial centerline of the References Cited rotor. The rotor is rotatable about an axis inclined to UNITED STATES PATENTS the crankshaft, and at a different speed than the 3,464,361 9/1969 Voser 418/68 crankshaft Theefme when the Crankshaft rotates 3,485,218 12/1969 Clarke 418/53 mutating rotary motion is imparted to the rotor 89 that 3,492,974 2 1970 Kreimeyer 418/53 its ribs follow the recessed face of the st ut Primary ExaminerWilliam L. Freeh Assistant Examiner-Michael Koczo, Jr.

Attorney, Agent, or Firm-Shlesinger, Fitzsimmons & Shlesinger [57] ABSTRACT The engine comprises a housing having a spherical 9 Claims, 7 Drawing Figures ROTARY NUTATING ENGINE This invention relates to rotary nutating devices, and more particularly to a nutating engine of the type having a stator and nutating rotor, and operable selectively as a motor or pump.

l-leretofore efforts have been made to provide a nutating engine of the type in which two segmental sections of a spherical body are rotated one relative to the other to compress a fluid between the confronting, recessed faces thereof. A major disadvantage of most such prior engines, however, is that one of these two sections of the engine i.e., either the rotor or the stator must be mounted for linear reciprocable movement relative to the other section.

It is an object of this invention to provide a novel nutating engine in which neither the rotor nor stator section thereof is mounted for linear reciprocable motion.

Another object of this invention is to provide a nutating engine of the type described in which the rotor section of the engine is mounted solely for rotary nutating motion relative to the stator section of the engine.

A further object of this invention is to provide an improved nutating engine, which is substantially less complicated and inexpensive to manufacture than prior such engines.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.

IN THE DRAWINGS FIG. 1 is a fragmentary, side elevational view of an engine made according to one embodiment of this invention, portions of the engine and its housing being broken away and shown in section for purposes of illustration;

FIG. 2 is a plan view of the rotor which forms part of this engine;

FIG. 3 is a sectional view taken along the line 33 in FIG. 2 looking in the direction of the arrows;

FIG. 4 is a side elevational view of the stator, which forms part of this engine;

FIG. 5 is a bottom plan view of the stator;

FIG. 6 is a plan view of a modified form of stator that may be used with this invention; and

FIG. 7 is a fragmentary side elevational view similar to FIG. 1, but showing a modified form of rotor that may be used with this engine.

Referring now to the drawings by numerals of reference, and first to the embodiment illustrated in FIGS. 1 to 5, l denotes generally an engine comprising a housing 11 having therein a central, segmentalspherical chamber 12. This chamber opens at its lower end of a circular recess 13, which is formed in the bottom of housing 11, and at its upper end on a reduceddiameter bore 14 that is formed in the upper end of the housing coaxially of chamber 12' and recess 13. Housing 11, which may be formed from two, like, separable sections that are releasably and sealing secured together by any conventional means, may be closed at its lower end by a bottom plate 16, and at its upper end by a cover plate 17.

Secured in the upper end of chamber 12 coaxially thereof is a segmental-spherical stator 21 (FIGS. 1, 4 and having an axial centerline denoted at Y-l, and a plane upper surface 22, which registers coaxially with the bore 14. The stator 21 is designed so that the center of its spherical surface is common with that of chamber 12. At its opposite or lower end (FIGS. 1 and 4) diametrally opposite sides of stator 21 are scalloped out or recessed to form therein opposed, generally segmentalconical hollows or

recesses

23 and 24, which radiate from a common point Xl (FIG. 5) on axis Y-l. The

recesses

23 and 24 are separated by aligned, segmentalconical ribs having aligned

apices

25 and 26 which also extend to point Xl.

Intermediate its ends the stator 21 has therethrough an axial bore 27 which opens at its upper end on the surface 22, and at its lower end on the recess 23 immediately adjacent the apex 26. Two additional

axial bores

28 and 29 are formed in the stator 21 to open at their upper ends on the surface 22, and at their lower ends on opposite sides, respectively, of the other apex 25 of the stator for a purpose to be noted hereinafter.

Numeral 31 (FIGS. 1 to 3) denotes the engine rotor. which also forms a segment of a sphere having the same diameter as the chamber 12 and the stator 21. The rotor has a plane, circular underside 32 disposed coaxially of the rotor axis Y-2 and lying in a plane extending normal to this axis. In its upper end rotor 31 has three, equi-angularly spaced hollows or

recesses

33, 34 and 35, which are generally segmental-concial in configuration, and which radiate from a common point X2 on the rotor axis Y-2. These recesses are separated by the three equi-angularly spaced crests or

apices

36, 37 and 38, each of which forms a straight line which is inclined from its upper end downwardly to the point X2 on the rotor 31.

The rotor 31 is mounted in chamber 12 beneath the stator 21 with its recessed upper surface confronting the recessed, lower surface of the stator. A spur gear 41 is secured to the underside 32 of the rotor coaxially of its axis Y-2 by a plurality of screws 42, or the like. A stub shaft 43, which is integral with the bottom of the rotor, projects coaxially through an axial bore in the gear 41, and rotatably into a registering recess 44 formed in the confronting surface of a mounting plate 45, which is integral with the upper end of the engine drive or crank shaft 46. Shaft 46 projects rotatably through a central opening 47, which is formed in plate 16 coaxially of the chamber Y-l.

Mounted intermediate its ends to rotate in the plate 45 in spaced, parallel relation to shaft 43 is a further shaft 50. Secured coaxially to opposite ends of the shaft 50 for rotation in spaced, parallel planes above and below, respectively, the plate 45 are two

gears

51 and 52. Gear 51 meshes with the gear 41; and gear 52 meshes with an annular bevel gear 53, which is secured by screws 54 to the inside surface of the plate 16 coaxially of shaft 46.

Referring now to FIG. 1, A denotes the angle that is formed between each of the three

rotor apices

36, 37 and 38 and the plane bottom surface 32 of the rotor, and by way of example may be 15. Angle B denotes the angle of inclination of the rotor axis (stub shaft 43) to the axis of the engine shaft 46, and is equal to angle A in the illustrated embodiment. Angle C represents the inclination of apex 38 to the horizontal at any given instant, and of course will vary depending upon the angular position of the rotor 31 relative to the stator 21.

For example, in FIG. 1 the stator 21 is shown from its position as illustrated in FIG. 4, so that its re-' cess 23 faces toward the right, and so that its aligned

apices

25 and 26 appear in FIG. 1 as a point registering with the intersection of axes Y-l and Y-2. The rotor 31, on the otherhand, has the same angular position as in FIG. 2 (i.e., the apex 38 extends toward the right),

but its axis Y-2 is inclined by the angle B to the axis Y-l of the stator so that the rotor apex 38 is in linear contact with the recess 23 in the stator along a line ex tending between the point X-l and the uppermost point (FIG. 1) in recess 23. Also at this time the other two

apices

36 and 37 of the rotor have linear contact with the recess or dwell section 24 of the stator adjacent opposite ends thereof. These three lines of contact between the rotor and stator, as represented by the

rotor apices

36, 37 and 38, are angularly spaced from each other 120 about the axis Y-2, and as noted hereinafter, rotate about the axis Y-2 and nutate about Y-l, when the rotor is nutating.

FIG. 1 shows angle C at a maximum value. The

gearing

41, 51, 52 and 53, is selected to cause the shaft 46 to rotate three revolutions for every one revolution of the rotor 31. Therefore, whenever the rotors apices 36, 37 and 38 are rotated 90 relative to the stator 21 (for example from the point in FIG. 1 where the apex 38 registers with the center of recess 23 to a point where the former registers with the stator apex 25) the shaft 46 will rotate 270 about its axis, or 180 relative to the rotor 31. During this 180 change in relationship between the rotor 31 and the shaft 46 the rotor apices do follow the contour of the stator, so that angle C will be decreased to approximately zero as apex 38 passes beneath the center of rib 25. This action, which imparts nutating motion to the rotor, is made possible because the rotor 31 contains a

recess

33, 34 or 35 directly opposite, or 180 from, each of its

apices

37, 38 and 36, respectively. Consequently, whenever any one of the rotor apices registers with one of the stator apices, a

recess

33, 34 or 35 in the rotor registers with the opposite high point or apex on the stator. Moreover, as the rotor revolves, the three, angularly spaced lines of contact defined by the

apices

36, 37 and 38 divide the chamber 12 between the rotor and stator into three, spaced pockets (two of which are denoted at P1 and P2 in FIG. 1), which vary in size and configuration as the rotor revolves.

When used as an internal combustion engine, and assuming that the rotor 31 rotates clockwise in FIG. 2 ia indicated by the arrow, two pipes or

tubes

61 and 62 may be used to connect the bores or

ports

28 and 29 in the stator to an exhaust system and to a fuel supply, respectively. Means for igniting the fuel, such as spark plug 63 (FIGS. 4 and may be mounted in the bore 27 in the stator and connected in known manner to a power supply. When the shaft 46 is rotated by a conventional starting mechanism (not illustrated), the rotor 31, as illustrated in FIG. 1, will continue to compress the contents of pocket P1 until the lowest point of the recess 33 has passed beneath the apex or high point 25 on the stator 21.. During this interval the exhaust port 28 is opened, and the pocket Pl diminishes in size until it reaches its smallest volume, so that any gas previously contained in the pocket P1 is exhausted out of the duct 28.

As soon as the lowest point of recess 33 passes beneath the stator apex 25, the pocket P1 begins to increase in volume, and also begins to draw into the pocket a fuel-air mixture from the fuel supply port 29..

During this movement pocket P1 revolves toward the position previously occupied by the pocket P2 (FIG. 1)

and increases in size as the rotor apex 36 approaches the apex 26 on the stator. After the apex 36 passes beneath the apex stator 26, the pocket P1 begins again to diminish in size, so that its contents (the fuel-air mixture) is compressed as the rotor recess 33 passes beneath the stator apex 26. When the lowest point of the recess 33 has passed beneath and slightly beyond the stator apex 26, the spark plug 63 is energized to ignite the now-compressed fuel-air mixture in the compressed pocket Pl, so that this mixture expands rapidly to provide the power which drives the rotor. The ignited mixture continues to expand, and the pocket Pl becomes larger as the rotor recess 33 rotates beneath the recess or dwell portion 23 of the stator. As the low point of recess 33 passes beneath the center of thc dwell 23 on the stator, the rotor apex 36 passes beneath the inner end of the port 28 on the stator to open this exhaust port so that the burned fuel in the pocket P1 is now exhausted out of the port 28 as the rotor recess 33 once again passes beneath the stator apex 25 as described,

above. This completes one revolution of the rotor 31 relative to the stator 21 From the foregoing it will be apparent that each of the three

recesses

33, 34 and 35 in the rotor forms part of successive compression and expansion operations as it passes beneath each stator.

apex

25 and 26. At any point during the operation of the engine, moreover, each of the three

rotor recesses

33, 34 and 35 is working at some phase of the combustion process; and at all times, the linear contact between the three

rotor apices

36, 37 and 38 and the confronting surfaces on the stator 21 operate to maintain the three corresponding pockets P1, P2, etc. sealed off from each other so that while a fuel-air mixture may be expanding in one pocket (for example P2 in FIG. 1), a previously burned mixture may be in a compression stage in the following pocket (for example P1 in FIG. 1).

Instead of operating as an internal combustion engine, 10, alternatively, could be employed as a fluid pump, in which case the shaft 46 would be driven by an external source. In such case a modified stator of the type denoted at 21 in FIG. 6 could be employed. This stator is similar to the above-described stator 21, ex-

cept that the spark plug bore 27 has been replaced by two, spaced, parallel, axially extending bores 28' and 29', which open on opposite sides of the apex 26 to function in a manner similar to the

bores

28 and 29.

In use, and assuming the rotor 31 is driven in the same direction as described in connection with the first embodiment, the

bores

29 and 29 would be connected to a fluid supply, while the bores 28 and 28' would be connected to a fluid pressure system, or the like. Then, as each recess in the rotor 31 passes beneath one of the

stator apices

25 or 26, the fluid in the associated pocket would first be compressed and forced out of one of the bores 28 or 28' to the associated pressure system, and thereafter, as soon as the pocket again began'to expand, fluid would be drawn into the expanding pocket from one of the supply bores 29 or 29'.

For example, referring to FIG. 1, and assuming that the engine 10 were designed withthe modified stator 21 to function as a pump, as the pocket P1 rotates beneath the stator apex 25, the fluid in the pocket would.

be compressed out of the bore 28 until the low point on the recess 33 passed beneath the high point of the apex 25 on the stator. Thereafter pocket Pl would again being to expand and fluid would be drawn into the pocket from the bore 29, and would subsequently be compressed and discharged out of the bore 28 as the recess 33 passed beneath the other stator apex 26.

In FIG. 7, wherein like numerals are employed denote elements similar to those in the first embodiment, 31 denotes a modified rotor, which may be used in combination with the stator 21 in a modified engine At its lower end the rotor 31' has a central, circular recess 70, which surrounds a reduced-diameter stub shaft 71, which is integral with the underside of the rotor coaxially of its axis Y-2. Shaft 71 is rotatably journaled in a bearing 72, which is secured in a circular recess or pocket 73 that is formed in an enlargeddiameter collar 74 that is integral with the inner end of the engine shaft 46. Collar 74 projects into the recess 70 above a bevel gear 53, which, as in the first embodiment, is secured on the inside of the base plate 16. The teeth of the bevel gear 53 mesh with the teeth of a ring gear 76, which is secured to the bottom of the rotor 31 coaxially of its recess 70.

Engine 10' is otherwise similar in configuration to the previously described engine, the modified gearing being such that the rotor 31' makes one revolution for each three revolutions of the shaft 46. This gives the rotor 31 the necessary motion to follow the sinuous configuration of the stator 21. By way of example, the ring gear 76 may have thereon fifty-one teeth, while the bevel gear 53 may have thereon thirty-four teeth. While the number of teeth may be varied, depending upon the size of the engine, the ratio should be maintained the same in order to produce the desired motion.

From the foregoing it will be apparent that the instant invention provides an extremely efficient and compact engine suitable for use selectively as an internal combustion engine or as a compression pump. While only a single fuel supply and a single exhaust port have been illustrated in the embodiment shown in FIGS. 1 to 5, it will be apparent that additional such ports can be used, if desired, and their placement can be varied. They may even be placed, for example, in the housing 11. Moreover, the engine (l0, 10') may, if desired, be diesel or glow without, therefore, requiring the use of a spark plug. In addition the engine could be operated as a fluid motor, in which case fluid under pressure could be applied through orifices at the bores 29 and 29' (FIG. 6), which would force expansion of the associated pockets P1, P2 etc. to impart the driving force for the motor; and the bores 28 and 28', would, in such case, function as the exhaust ports, to allow evacuation of the fluid from the pockets.

Also, while the stator has been described as being a part separated from the housing 11, it could be made integral therewith if desired. Furthermore, it will be apparent that the number of recesses in the faces of the stator and rotor may be increased, if desired, provided the number of recesses in one of them exceeds by one the number of recesses in the other, and provided also a corresponding change is made in the gearing which produces relative rotation between the rotor and the crankshaft. Also, the apices of the ribs in the stator face could be other than aligned, provided, of course, a corresponding compensation is made in the inclination of the rotor ribs to the rotor axis.

While only certain embodiments of this invention have been illustrated and described in detail herein, it will be apparent that this application is intended to cover any such modifications of the invention which may fall within the scope of one skilled in the art, and the appended claims.

Having thus described my invention, what I claim is:

1. An engine, comprising a housing having therein a spherical chamber,

a solid, segmental-spherical rotor movably mounted in said chamber adjacent one end thereof and having a solid operating surface confronting a stationary operating surface formed in said chamber adjacent the opposite end thereof, said operating surfaces having centers which coincide with the center of said chamber,

each of said operating surfaces having therein a plurality of generally segmental-conical recesses emanating radially from the center of the surface and forming thereon a plurality of equi-angularly spaced ribs which project radially between said recesses from adjacent the last-named center to points immediately adjacent to the spherical wall of the chamber,

a shaft supported in said housing adjacent one end there and extending part way only into said chamber at said one end thereof and rotatable about a first axis extending through the center of said chamber,

means mounting said rotor on the inner end of said shaft for rotation relative to said shaft about a second axis extending through the center of said chamber and inclined to said first axis, and for rotation with said shaft about said first axis, and

connecting means between said shaft and said rotor for causing said shaft to revolve three times about said first axis for each revolution of said rotor about said second axis, thereby to impart rotary and nutating motion to said rotor to maintain said ribs on the operating surface of said rotor in sliding engagement with the stationary operating surface, whereby a plurality of revolving pockets are formed between said operating surfaces and the wall of said chamber and alternately expand and contract during rotation of said rotor and said shaft.

2. An engine as defined in claim 1,wherein there are three of said recesses in the operating surface of said rotor separated by three ribs the apices of which are inclined to each other and to said first axis,

there are two of said recesses in the stationary operating surface separated by a pair of ribs having apices extending transverse to said first axis, and

the angle of inclination of the apex of each of said three ribs on said rotor is equal to the angle of inclination of said second axis to said first axis.

3. An engine as defined in claim 1, wherein said shaft projects exteriorly of said housing, and

said connecting means between said shaft and said rotor is operative upon rotation of said shaft to impart relative rotation to said rotor and vice versa.

4. An engine as defined in claim 3, wherein said connecting means comprises a first gear fixed to said housing coaxially of said shaft, and a second gear fixed to said rotor and meshing with said first gear to effect said relative rotation between said shaft and said rotor.

5. An engine as defined in claim 3, wherein said connected means comprises a first gear fixed to said housing coaxially of said shaft.

a second gear secured to said rotor coaxially of said second axis, and

a pair of planetary gears interposed between said first and second gears and operative to effect said rela tive rotation between said shaft and said rotor.

6. An engine as defined in claim 5, including a stub shaft projecting from said rotor rotatably into a cylindrical recess formed in one end of the firstnamed shaft coaxially of said second axis, and

an idler shaft rotatably mounted in said one end of said first-named shaft to rotate in spaced, parallel relation to said stub shaft,

said planetary gears being secured to opposite ends of said idler shaft and meshing with said first and second gears, respectively.

7. An engine as defined in claim 1, including means in said housing for conveying fluid to each of said pockets during the expansion thereof, and for exhausting said fluid from said pockets to the exterior of said housing during the contraction of said pockets.

8. An engine as defined in claim 1, including means in said housing for supplying fuel to each of said pockets during alternate expansion stages thereof, thereby to effect compression of said fuel upon the alternate compression stages of each pocket which follow said alternate expansion stages thereof,

means for igniting the compressed fuel in said pockets at the commencement of the intervening expansion stages of the pockets, and

means in said housing for exhausting burned fuel from said pockets during the intervening compression stages thereof, which follow said intervening expansion stages.

9. An engine, comprising a housing having therein a segmental-spherical cham ber,

a shaft rotatably mounted intermediate its ends in one end of said housing, and having an inner end projecting part way only into said chamber,

a stator fixed in said chamber opposite said shaft and having an operating surface the center of which coincides with the center of the sphere of which said chamber is a segment, i

a segmental-spherical rotor in said chamber between said stator and said shaft and having an operating surface confronting the operating surface of said stator, and having its center coinciding with the center of said sphere,

said stator having in its operating surface a pair of equi-angularly spaced, generally segmental-conical recesses emanating from the center of the stator operating surface and forming thereon a pair of generally segmental-conical ribs projecting radially from its center between said recesses,

said rotor having in its operating surface three equiangularly spaced, generally segmental-conical recesses emanating from the center of the rotor operating surface and forming thereon three equiangularly spaced ribs having linear apices extending radially outwardly from the center of the rotor operating surface, and

means mounting said rotor on said inner end of said shaft for rotary, nutating movement about the center of said stator operating surface, thereby to maintain the apices of said ribs on said rotor in sliding contact with the operating surface of said stator during said movement,

said mounting means including means connecting said shaft to said rotor to impart relative rotation therebetween at a rate of threee revolutions of said shaft for each revolution of said rotor.

Claims

1. An engine, comprising a housing having therein a spherical chamber, a solid, segmental-spherical rotor movably mounted in said chamber adjacent one end thereof and having a solid operating surface confronting a stationary operating surface formed in said chamber adjacent the oppoSite end thereof, said operating surfaces having centers which coincide with the center of said chamber, each of said operating surfaces having therein a plurality of generally segmental-conical recesses emanating radially from the center of the surface and forming thereon a plurality of equi-angularly spaced ribs which project radially between said recesses from adjacent the last-named center to points immediately adjacent to the spherical wall of the chamber, a shaft supported in said housing adjacent one end there and extending part way only into said chamber at said one end thereof and rotatable about a first axis extending through the center of said chamber, means mounting said rotor on the inner end of said shaft for rotation relative to said shaft about a second axis extending through the center of said chamber and inclined to said first axis, and for rotation with said shaft about said first axis, and connecting means between said shaft and said rotor for causing said shaft to revolve three times about said first axis for each revolution of said rotor about said second axis, thereby to impart rotary and nutating motion to said rotor to maintain said ribs on the operating surface of said rotor in sliding engagement with the stationary operating surface, whereby a plurality of revolving pockets are formed between said operating surfaces and the wall of said chamber and alternately expand and contract during rotation of said rotor and said shaft.

2. An engine as defined in claim 1,wherein there are three of said recesses in the operating surface of said rotor separated by three ribs the apices of which are inclined to each other and to said first axis, there are two of said recesses in the stationary operating surface separated by a pair of ribs having apices extending transverse to said first axis, and the angle of inclination of the apex of each of said three ribs on said rotor is equal to the angle of inclination of said second axis to said first axis.

3. An engine as defined in claim 1, wherein said shaft projects exteriorly of said housing, and said connecting means between said shaft and said rotor is operative upon rotation of said shaft to impart relative rotation to said rotor and vice versa.

5. An engine as defined in claim 3, wherein said connected means comprises a first gear fixed to said housing coaxially of said shaft. a second gear secured to said rotor coaxially of said second axis, and a pair of planetary gears interposed between said first and second gears and operative to effect said relative rotation between said shaft and said rotor.

6. An engine as defined in claim 5, including a stub shaft projecting from said rotor rotatably into a cylindrical recess formed in one end of the first-named shaft coaxially of said second axis, and an idler shaft rotatably mounted in said one end of said first-named shaft to rotate in spaced, parallel relation to said stub shaft, said planetary gears being secured to opposite ends of said idler shaft and meshing with said first and second gears, respectively.

8. An engine as defined in claim 1, including means in said housing for supplying fuel to each of said pockets during alternate expansion stages thereof, thereby to effect compression of said fuel upon the alternate compression stages of each pocket which follow said alternate expansion stages thereof, means For igniting the compressed fuel in said pockets at the commencement of the intervening expansion stages of the pockets, and means in said housing for exhausting burned fuel from said pockets during the intervening compression stages thereof, which follow said intervening expansion stages.

9. An engine, comprising a housing having therein a segmental-spherical chamber, a shaft rotatably mounted intermediate its ends in one end of said housing, and having an inner end projecting part way only into said chamber, a stator fixed in said chamber opposite said shaft and having an operating surface the center of which coincides with the center of the sphere of which said chamber is a segment, a segmental-spherical rotor in said chamber between said stator and said shaft and having an operating surface confronting the operating surface of said stator, and having its center coinciding with the center of said sphere, said stator having in its operating surface a pair of equi-angularly spaced, generally segmental-conical recesses emanating from the center of the stator operating surface and forming thereon a pair of generally segmental-conical ribs projecting radially from its center between said recesses, said rotor having in its operating surface three equi-angularly spaced, generally segmental-conical recesses emanating from the center of the rotor operating surface and forming thereon three equi-angularly spaced ribs having linear apices extending radially outwardly from the center of the rotor operating surface, and means mounting said rotor on said inner end of said shaft for rotary, nutating movement about the center of said stator operating surface, thereby to maintain the apices of said ribs on said rotor in sliding contact with the operating surface of said stator during said movement, said mounting means including means connecting said shaft to said rotor to impart relative rotation therebetween at a rate of threee revolutions of said shaft for each revolution of said rotor.