CA1041436A - Rotary engine - Google Patents

Abstract

ROTARY ENGINE

ABSTRACT OF THE DISCLOSURE
The present invention is a new rotary engine consisting of a stator with a cylindrical cavity, a hollow cylindrical rotor located within the cylindrical cavity of the stator, a power shaft along the axis of the stator and an eccentric mounted on the power shaft. A plurality of spaced vanes are mounted in the stator for reciprocal movement with respect to the stator to provide working chambers between adjacent vanes, the stator, and the rotor so that rolling movement of the rotor around the interior of the stator in response to combus-tion of explosive charges in the chambers causes the eccentric to roll around the inner surface of the rotor and thereby rotate the power shaft.

Description

13ACI~GROUND OF T~IE INV13NTION
Many designs for rotary engines have been proposed. Representative ~: prior art rotary engines are shown; for example, in U,S. 2,9b7,307; U.S.

2,005,141; U.S. 1,974,761; U.S. 1,305,451; U.S. 3,624,7~0, andU.S.

3,194,220.
SUMMARY OF T~IE Il~VENTION
The present invention i6 a new rotary engine. This rotary enBne comprises: a stator having spaced end walls and a peripheral wall inter-connecting the end walls to form a cylindricl~l cavity having an axis, the inner0urface of the peripheral wall having a substantially circular profile; a hollowcylindrical rotor having an outer and inner surface, each having a substantiallycircular profile, and supported in the cavity for rolling mation with respect tothe inner ~urface of the stator about an axis spaced from but paralle} to the stator axis; the rotor having an internal diameter such that the stator axi6 i6 .;~ .,~1 ' . ' 1 .~ .

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1 ~6~4~9L36 located inside the inner surface of the rotor and an external diameter that i6 less than the diameter of the inner surIace of the ætator; means for sealing theouter surface of the rotor with respect to its inner surface; an eccentric mounted within the inner surface of the rotor for rotation about the stator axiæand in rolling contact with the inner aurface of the rotor, whereby in operationthe rotor axis describes a ~7ubstantially circular path around the stator axis; a plurality of spaced vanes mounted in the stator in sealing relationship with theend walls for reciprocal movement with respect to the inner surface of the stator;
.- . means for holding the vanes in sealing engagement with the outer ~urface of the rotor; .whereby at least two chambers, at least one of which is a working chamber, are defined by adjacent vanes, the outer surface of the rotor, the inner surface of the sitator, and the end wall~ of the ~tator; the ætator having`.~ an intake port for admitting fuel to the working chamber and an exhaust port for discharging exhaust products from such ohamber. . .
In the operation of the engine, ignition of the fuel causes the rotor to .
roll around the inner surface of the peripheral.wall of the cylindrical cavity : . o the stator. This rolling movement of the rotor causes the eccentric, ~rhich .' is in rolling contact with the inner surface of the rotor, to revolve around the axis of the sitator describing the path tr~.ced by th0 axis of the rotor and thereby rotate the power shaft.
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DESCRIPTION OF THE DRAWINGS
, ~' ~ _ PIG. 1 iæ a cro~s æectional view througb the rotary engine of this mvention;
FIG. 2 is a ~iectionial view taken along the ]ine 2-2 of FIG. l; and :;
2~ ~ ~ FIGS. 3-12 are schematic vieYVB illustrating the cycle of the rotary engine of this invention through two revolutionæ.
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Il (4~fi) I ~ 43~i ¦ DESCRIPTION OF THE PREFERRE:D EMBODIMENT
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Reference will now be made in detail to thle present preferred embodiments of the invention, an example of which iB iLlustrated in the accompanying drawings.
~ s shown in FIGS. 1 and 2, the rotary engine of this invention consists generally of a stator 20 located within a housing 22 and a rotor 24 rotatably supported within stator 20.
In accordance with the invention, stator 20 comprise~ a pair of spaced end walls 26 and a peripheral wall 28 interconnecting end walls 26 to form a cylindrical cavity 30 having an axis 32. As best shown in FIG. 2, the inner surface 34 of peripheral wall 28 has a substantially circular profile.
In accordance with the invention and af~ best shown in FIG. 1, rotor 24 is a hollow cylinder supported in stator cavity 30 for rolling motion around the inner surface 34 of the stator about an axis 33 spaoed from, but parallel to, stator axis 32. The outer surface 38 of rotor 29 has a substantially circular profile and a diameter less than the diameter of the circular inner surfao~ 34 of stator 20.
' ¦ Preferably, and as more fully described below, the diameter of outer surface 38 is at least about 70%, and more preferably from about 75% to about ~5%, ¦ of the diameter of stator cavity 30. Further, and as best seen in FIG. 1, the 20 ¦ inner surface of hollow rotor 24 also has a substantifllly circular profile and a diameter that permits the stator axis 32 to be located inside the inner surface 40 of the r~tor.
¦ ~ In ac&ordance with the invention, means are provided for sealing the ¦ outer surace 38 of rotor 24 with respect to its inner surface 40. As embodied, ¦ and r- bes~ sho~ in Plb. a, this means comp-ises an annul~r st~aling ring 42 ~ .

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(4B0E) ~ 6 . ~ . journaled in a groove 44 extending around the outer edges 46 of both ~ides of rotor 24. The6e sealing rings 42 are biased again6t end wall6 26 of 6tator 20 to movably seal the volume inside of rotor 24 from the volu}ne betwe~n rotor 24 and stator 20. In~ide of rotor 24 and along 6tator axis 32 is mounted a power ~haft 50 that ia journaled in bearings 52 in end wall6 26 ~nd extends out through :' housing 22, In accordance with the invention, an eccentric 54 i~ mounted on power shaft 50 for rotation about stator axis 32. Eccentric 54 aupports rotor 24 in stator .. cavity 30 and id in rolling contact with the inner ~urface 40 of the rotor, so that as eccentric 54 rotates about ~tator axis 32 respon~ive to rolling movement o~ rotor ., 24 within atator cavity 30, the axis of rotor 24 deacribea a aub~tantially c~rcular path, aa shown in FIG. 1, around stator axis 32.
To provide for rolling contact between eccentric 54 and the inner surface .. of rotor 24, a low friotion bearing 56 is rollably mounted around the outer surface of eccentric 54. .
ln accordance with a preferred embodiment of the invention, and a~ more 1 ~ . fully de6cribed below in connection with the operation of the rotary engine, the ; 1~ radial length 58 of eccentric 5~ from stator axis 32 plus the distance between the inner surface 40 and outer aurface 38 of rotor 24 is es6entially equal to, but slightly less than, the radius of the oircular inner ~urface 34 of 6tator peripheral wall 28 to provide for maximum compreasion and exhaust of the explosive charge in the engine.
To provide working chambers Cdpable of containing an explosive charge for compression by the rotary motion of rotor 24, a plurality of vane6 60 are .
6~1idably mounted in the peripheral wall 28 of 6tator 20 for reciprocal movement ! _ 4 _ .'',;~
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6~6) 1 ~4~36 ¦ with respect to tke inner surface 34 of the stator. Preferably, and as best 6hown ¦ in FIG. 1, vanes 60 reciprocate in a substantially radial direction with re6pect ¦ to stator axis 32 and move in sealing relationship with end walls 26 of the stator.
¦ In accordance with the invention, mean~ are provided for guiding and ¦ supporting vanes 60 during such reciprocal movement. As embodied, and as best 6hown in FIG 2, thi~ guide means comprises slots 62 in end walls 26 that extend in a radial direction over the length of travel of the vanes. <_.¦ In addition, vanes ~0 are biased into 6eaiing engagement with the outer 1 surface 38 OI rotor 24 regardless of its relative position within stator cavity ¦ 30, and means are provided for holding these vanes in sealing engagement with ¦ the rotor. As embodied, and as shown in FIG. 1, this mean~ can include springs 64 a6 well as the pressure of the compressed gas i~ the working chambers.
Thus, vanes BO provide a plurality of circumferentially spaced working chambers around the inner surface of 6tator 20, each working chamber being defined by , 15 adjacent vane~ 60, the outer aurface 38 of rotor 24, and the inner ~urface 34 and the end walls 26 of ~tator 20.
~1 ~ For each working chamber there is also provided an intake port 70 for ad~nitting fuel to the working chamber and an exhaust port 72 for discharging exhaust products from each chamber. Optionally, ignition means, such as a spark plug 74, can be provided for each workit~g chamber depending on the type oi fuel being u~ed, as i~ well known to those skilled in the ort.
;J~ In accordance with a preferred embodiment of the invention, Intake and ; ~ exhaust ports 70, 72 are provided with auitable valves 76 for opening and closing such portG and mean6 are provided for controlling operation of these valves. As ¦ ~hown in FIG. 2, meen~ fo~ oontroiling the valve= ino udee ~ cem-drive geer 78 ¦

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65t) 1 ~0~1~36 ¦ affixed to power ihaft 50. Cam-drive gear 78 drives suitable cam gears 80 ¦ which, in turn, actuate the movement of val-res Y6 through lever arm 82.
¦ An intake mani~old 84 provides the nece&sary access for the combustion ¦ mi~ture to intake port 70 and a similar exhaust manifold 86 connected to exhaust ¦ port 72 provides for the necessary discharge of exhaust ga6es following ¦ combustion.
¦ While the rotaxy engine, shown in the drawings, con~ists of five (5) vanes ¦ 60 and five ~5~ working chambers with the necessary intake, e~hau~t and ignition ¦ means for each chamber, it can be readily understood by those skilled in the art ¦ that any number of working chambers can be provided without departing from the 6cope of this invention. Preferably, the rotary engine has at least three (3~
¦ vanes to provide at least three (3) working chambers and, a~ more fully described ¦ below, it is preferred to use an odd number of working chambers .
I For purposes of illustration, the rotary engine of this inyention will now be 15 ¦ de~cribed a~ it relates to a typical four-cycle ~asoline en~ine operation of com-bustion~ exhaust, intake and compres~ion. Bue, it should be understood that the I ~ invention can al~o be uoed in a two-cycle mode without depa~ting from the scope : ¦ of the invention.
Referring to FIGS. 3-12, FI(:. 3 shows the beginning of the power stroke after firing of the explosive charge in working chamber A . At firing,the intake and exhaust ports are closed. FIG, 4 shows the continuing power stroke and the resulting clockwi~e rotation oE eccentric 54 and power shaft 50.
FIG. ~ ehow the end of the power stroke of working chamber A and the start o~ the exhaust ~troke in which the exhau6t port is open and the intake port iB olo~ed. FIG. 6 6hows the continuing exhau~t stroke, and by the time the rotor ~ . ' ~ ~ -6-'~ ~ .~
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: ' ' ' , ' a~) ~ 36 ¦ reaches the posit.on shown in FIG. 7, exhaust i8 nearIy complete. The I exhaust port then closes, and the intake port open~ so that when the rotor reaches ¦ the position shown in FIG. 8 the intake of a combustible mi~ture into chamber I A ha~ begun.
¦ FIG. 9 show~ continuing intake OI wmbustible mixture, and FIG. 10 showa ¦ the completion of the intake stroke at which point the intake port closes and the ¦ eompression fitroke on the combustible mixture in working chamber A begin6.
I With the rotor in a position shown in FIG. 11 the compression stroke continue~¦ and FIG. 12 is near the end of the compreasion stroke, the combustible fuel will lO ¦ then be igmted as shown in FIG. 3, and the cycle repeated.
Exactly the same sequence i8 taking place in the other five working chamber~
I of the rotary engine, illustrated in FIGS. 3-12. To facilitat~ this un;~lerstanding, ¦ the other working chambera have all been ~tippled at the point where ignition ¦ occurs in each chamber. Thus, for e~ample, when working chamber A is at 15 ¦ the end of its power stroke, as ~hown in FIG. 5, working chamber C i~ firing.
¦ Then, when working chamber C is at the end of its power stroke and working ¦ chamber A ia near the end of it8 exhaust stroke, as shown in FIG. 7, working I chflmber E iz fired.
¦ Following through ~e cycle, it can be seen, then, that working chamber 20 ¦ B ia fired, aa ahown in FIG. ~, when working chamber A is on the intake stroke.
Finally, the last working chamber D is fired during me compres~ion stroke of working chamber A, aa shown in FIG. 11, and then working chamber A i~ fired again repeating the cycle. It can, thus, be ~een that the rotor make~ two complete ¦ revolutions between the firing of each chamber to provide for the necezaary intake, 25 ¦ compression, combustion, and exhaust operations of the four-cycle engine.
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~ 43~ ;~636~ 1 In view of the simplicity of the rotary engine of the pre6ent invention, it is not necessary to use highly sophisticated designs and complex construction techniques . The stator can conveniently be made from a bored cast iron or aluminum block with end walls covering both ends. The rotor can be a hollow metal cylinder of the appropriate diameter.
The power shaft can be a 6alid rod. The ecaentric may take many forms, but preferably it will not occupy the entire space defined by the inner ~urface of the rotor, but will leave more thsn half that space open. By having a substantial amount of the space defined by the inner surface of the rotor open-, it is possible to pas~ a cooling fluid or gas through the center of the rotor toachieve extremely effective engine cooling, becau3e the outer surface of the rotor . forms portions of the working chamber~ of the engine.
Ideally, the eccentric will also be designed in a shape whereby the bulk of its weight is located on the 6ide of the rotor that is farthest from the inner wall of the ~tator and clo8e9t to the stator a~si 80 that this imbalance of weig~ht ¦ in the design of the eccentric can serve to counterbalance the eccentricity of the ¦ path that is followed by the rotor and ecoentric about the stator axis.
It is of the essence of the present invention, that the eccentric be mounted .
¦ within the inner surface of the rotor in a manner whereby the eccentric i6 ¦ in rolling contact wth the inner ~urface of the rotor. The eccentric may ,~ . ¦ conta¢t the inner surface of the rotor st one or more points but at each of the6e points, the eccentric should be in rolling contact with the inner ~urface of the rotor. Roller beRrings mounted on the eccentric can 6erve to provide . ~uch rclling cl~r t .

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~ (46DI3) 1 ~ 436 Any kind of frictional or sliding contact can defeat some of the prime ¦ advantages of the present invention. Frictional or sliding cotltact between ¦ the eccentric and inner surface of the rotor will cause the rotor to rotate within ¦ the ~tator in excesæ of its normal rotational movement and to rub or slide against ¦ the sealing vanes, causing rapid and unacceptable wear and attrition of the I vanes.
¦ AB embodied in the present invention, the vanes themselves can be made I from 6imple machined flat pieces of metal, and the operating end or sealing end ¦ of the vanes can be notched or cut back to fit over the outer surface of tbe rotor 10 ¦ and yet extend towards the center of the engine past the outer surface of the ¦ rotor in the portion of the vanes that i8 carried in slots in the end wall8 of the ¦ stator. This overhang or extension of the 6ealing vanes past the outer surface 1 of the rotor within the end walls of the YtatOr enhances the sealing effecti~eni,3ss ¦ of the vanes in sealing adjacent chambers of the engine at the end walls.
15 ¦ Valves, spark plugs, cams, and carburetors for the engine may all be selected from a wide variety of such device6 that are conventional and readily , ¦ availabls.
An outstanding feature of the rotary engine of this invention i8 the large I cubic mch displacement that can be obtained with a relatively small engine.
20 1 For example, a rotarsr engine having a statcr with an internal radiu,s of 2. 5 inches, ¦ a rotor having an external radius of 1.875 inches~ and a width o~ 2 inches, ¦ would have a cubic inch displacement of about 28 cubic inches. Thi6 ~rery small '; ~ ¦ engine would generate about 30 horsepower at 4000-~000 r.p.m.
¦ In the drawings of the present invention all chamber,s are u,sed for firing.
25 1 Thia is very desirable for uniform heat~ng of the engine. However, to as,sist ¦ ~ in taking the heat out of the engine, the engine can be desi,gnied i30 that some : . .

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` ~ ~04~36 of its chamberA a.e used for cooling only. ~or exampie, alter~ating chambers ¦ can have a continuous flow of air pa~sing through the chamber. This help6 to ¦ cool the engine, and at least part of the heated cooling air can then be COIl-¦ veniently used in the combustion mixture.
¦ The drawings of the invention also show es~entially uniform spacing between I vanes. Although this is certainly a desirable de~ign, other designs are pos~ible, ¦ and an uneven spacing between the vane~ may be desirable for optimum engine operation in certain oases. .
I The vanes may be biased against the rotor by ~pring action, pneumatic 10 I force, or any other force. In the preferred practice OI the invention, pneumatic ,, ¦ pressure i-s at least partially u~ed to bias the vanes against the rotor. This ¦ pneumatic action causes greater pre6sure on the vanes against the rotor in thepower and compres~ion cycles and less pressure on ehe vanes in the intake &nd exhaust cycles. .
15 I Thus~ in accordance with the present invention, when the most severe ¦ sealing requirement exists during the compression and power cycle~, becau~e . it is then that the higheEt pressures are encountered, the greatest pneumatic ~ force to press the vanes against the outer surface of the rotor iE exerted.
¦ ConverEely, when the lea~t sevexe ~ealing is ~equired, namely, during the ,~ 20 1 intake and exhaust cycles, the pres~ure exerted on the vane againAt the rotor ~' ¦ .iB lowest. Thus, adequate and appropriate sealing i~ maintained at each point in the rotational cycle.
¦ The vane~ divide ~ection~ of the engine into chambers. There mu~t be I at least two vaneE, but three or more vanes are preferred, and there is no '~ 25 ¦ theorebcal upper limit to the ~umber of vanes that can be used with the rotary engine of thi~ invention, , . .
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~ 36 Although an even number of combu6tion chambers can be used, the use of an odd number of combustion chambers i~ prel`erred, because a full cycle on two revolutions of the rotor i9 obtained with an odd number of chamberz.
If an even number of combustion chambers is used, the timing and chamber firing sequence is more complex.
As a general rule, it has been found that with a given stator and rotor, the compresslon ratios of the engine are a funotion of the spacing betwçen the vanes. T~e narrower the spacing between the vanes, the higher the compressioII
ratios that are pos~ible. Thus, if higher compression ratios are de6ired, narrower spacings can be used, For example, by combining a high compression ratio with adequate direct cooling in the chamber, it is possible to have a narrow combustion chambçr betwee two vanes where a high compre~ion combustion takes place. The chamber directly .
following this combustion chamber can be a relatively broad cbamber with a continuous flow of air for cooling.
The relative diameters of the inside of the stator and the outside of the rotor are also important. In the broad concept of the invention any inside diameter oP the stator can be used. The out~ide diameter of the rotor i9, however, limited by the inside diameter of the ~tator, but the outside diameter of the rotor can be almost as large as the inside diameter of the ~tator.
The minimum outside diameter of the rotor i9 limited to a value ~llghtly larger than the inside radiua of the stator. In Ule preferred rotary engine, the outside diameter of the rotor is at least about 70~6 and more preferably Prom about 75 to about ~5% of the inside diameter of the stator.
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The relative diameter~ of the rotor and the inner surface of the ~tator have a direct bearing upon the compression ratios that can be obtained. As a general proposition, in an engine containing three or more combustion chambers, the compression ratio increases as the difference between the diameter of the rotor and the diameter of the inner surface of the 6tator decrea~es.
The eccentric is mounted on the power shaft (which i~ concentric with f~
the stator axis), and i6 contained within the 6pace defined by the inner surface- of the rotor. The eccentric must be of such a size and ~hspe that it allows the rotor to roll around or near the circumference of the inner 6urface of the ~tator.
A6 the rotor rolls around the inner ~urface of the stator, the eccentric rolls on the inner surface of the rotor at the points of contact between the inner 6urface of the rotor and the rollers or low-friction bearing6 on the eccentric.
!~ As noted previously, the eccentric may have a wide variety of de~igns.
In the drawings, the eccentric is depicted as a ~olid circular disc with a xoller bearing around the out~ide of the entire di6c. The eccentric could also be a narrow e~tended arm having rolling contact with the inner surface of the rotor ~; adjacent the portion of the rotor that is closest to the inner surface of the ~tator with a counterweight portion on the other side of the stator axi~ . The counter-welght portion al60 preferably i6 in rolling contact with the inner surface of the rotor. Various other 6hape6 could also be devi6ed to provlde for counter-balancing the eccentric.
' The rotary engine of the present in~ention has many attributea that make i~ it an ea:tremely useul power source.
(:)ne of the important features of the rotary engine is its eaae of construc-tion. All major parts of the present engine can ea~ily be made on conventional . ' ' . ,:

5) ~ 36 ¦ lathes and boring and milling machinee. Moreover, tlie simplicity of the rotor ¦ design makes side sealing of the rotor easy to accomplish. No gear~ are required ¦ to transfer the energy to the power ahaM or to ensure that the engine remain~
¦ in phase, as is required in the well-known Wankel rotary engine. In the present ¦ design, the eng~ne power shaft is directly driven by the eccentric.
¦ In the rotary engine of this invention, combustion can take placé at any ~ , portion of the inner surface of the cylindrical cavity of the stator. As a result, I the heat generated is distributed evenly throughout the engine and thermal distor-¦ tions can be minimized.
¦ Another important advantage of the present rotary engine i~ that the power ¦ shaft rotate~ once per revolution of the rotor. Thu~, the engine i8 capablF of ¦ operating at very high rotor revolutions per minute. Thi~ characteristic is importar t, ¦ because high revolutions per minute of the rotor are required for maximum power ¦ output. Engines that have high shaft revolutions per revolution of the rotor, ~ such as the ~Vankel ~ngine which has three shaft revolutions per rotor revolution, ¦ require special and expensive gearing to permit practic~1 power talce of from the shaft, ¦ ~n the rotary engine of the present invention, the number of firings per ¦ rotor revolution is dependent upon the number of combustion chambers. As ~0 ¦ a rule, the number of firings per revolution of the rotor are half the number of combustion ohambers. Thus, in the cour6e of two revolutions all combustion chambers will fire. Most convenient for purposes of firing design are tho~e ~; I versions of this invention ~n which the engine has an odd number of chamber~.
With an odd number of chambers, the firing sequence i~ repeated every two 25 ~ ¦ revolut~ons. Whereas, with an even number ofrevolution~ii it may be nece6sary ¦ to 6kip or omit oertain firing3.

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1 10~43~j One very important advantage of this invention i~ that the engine can operate at very high compression ratios, which can be a~ high a~ the diesel range.
Many other rotary engines cannot directly obtain such high compression ratios.
AB previously noted, in the present rotary engine the compression ratio i~ mainly dependent upon the relative outside diameter of the rotor in comparison to the .internal diameter of the stator, and upon the spacing between vanes.~, ~' One of the most distinctive advantageous features of the present invention :' . i8 the manner in which the rotary engine is ~eparated into combustion chambers.
Most engines containing vanes rely on a ~eal that is in sliding engagement with the outer surface of the rotor or the inner eurface of the stator. In the present invention, however, the rotor rolls over the ~ealing vane at the position of iull retraction of the vane into the stator. At this position, there i~ little or no sliding , motion between the vane and the rotor. .
, This iB an extremely important benefit of this invention, because at the point of full retraction of the vane into the stator the chamber pres~ures are at their hlghest. From ~e drawings, it can be seen that it ia at relatively ul1 retraction of the vane into the stator that the aompreslion and power ~trokes ocaur. For these pneumatically actuated vane~, the rolling motion of the rotor over the vane i~ at a maximum at the same time that the pressure of the vane agsin6t the rotor is at a maximum. Wear is thereby minimized.
;i ~ The above àiscussion should not be taken to indicate that there iB no ~liding motion between 'the vanes and the rotor. 'There, indeed, i8 ~ome sliding motio~1.
,~ ~ Thia sliding~action is an approximately direct unction of the differences in t~e outer diameter OI the rotor and the inner diameter of the ~tator. A~ thls differenae ; 25 increases, the amount of sliding action increases. In a representative engine :
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of the present invention, the rotor makes &bout 10 to 15 revolutions in the time that the vanes 61ide completely once around the outer surface of the rotor. This i6 a small amount of sliding motion and does not cause sub~tantial wear on the vane~, in contrast to the extensive wear experienced in the Wankel, and many other rotary engines, in which the vaneæ travel the entire length of the inner surface of the stator per revolution.
.A very important point with regard to the ~liding action that doHs occur is that such sliding action tnke~ place at pressures during which the intake &nd scavenging ~trokes are taking place. Thu~, there i8 a minimum of stress on the vanes when ~liding does occur. In accordance with this invention, for pneumatically actuated vanes, the sliding motion between thc rotor and the vanes is maximized when the pressure exerted by the vane against the rotor i~ minimized, and wear due to sliding i8 thereby also minimized.
These and other attributes of the engine of this invention make it a particularly dr~ira e, compact, and highly eifioient power aouroe.
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Claims (18)

WHAT IS CLAIMED IS:

1. A rotary engine comprising:
a stator having spaced end walls and a peripheral wall interconnecting the end walls to form a cylindrical cavity having an axis, the inner surface of the peripheral wall having a substantially circular profile;
a hollow cylindrical rotor having an outer and inner surface, each having a substantially circular profile, and supported in the cavity for rolling motion with respect to the inner surface of the stator about an axis spaced from but parallel to the stator axis;
the rotor having an internal diameter such that the stator axis is located inside the inner surface of the rotor and an external diameter that is less than the diameter of the inner surface of the stator;
means for sealing the outer surface of the rotor with respect to its inner surface;
an eccentric mounted within the inner surface of the rotor for rotation about the stator axis and in rolling contact with the inner surface of the rotor, whereby in operation the rotor axis describes a substantially circular path around the stator axis;
a plurality of spaced vanes mounted in the stator in sealing relationship with the end walls for reciprocal movement with respect to the inner surface of the stator;
means for holding the vanes in sealing engagement with the outer surface of the rotor;
whereby at least two chambers, at least one of which is a working chamber, are defined by adjacent vanes, the outer surface of the rotor, the inner surface of the stator, and the end walls of the stator;
the stator having an intake port for admitting fuel to the working chamber and an exhaust port for discharging exhaust products from such chamber.

2. The rotary engine defined in claim 1 in which the external diameter of the rotor is at least about 70 percent of the diameter of the inner surface of the stator.

3. The rotary engine defined in claim 2 in which the external diameter of the rotor is 75 to 95 percent of the diameter of the inner surface of the stator.

4. The rotary engine defined in claim 1 which includes means for using the differential gas pressure in adjacent chambers of the engine for at least partially holding the vanes in sealing engagement with the outer surface of the rotor.

5. The rotary engine as defined in claim 1 which has at least three vanes.

6. The rotary engine as defined in claim 1 which has an odd number of working chambers.

7. The rotary engine defined in claim 1 in which the vanes reciprocate substantially radially with respect to the stator axis.

8. The rotary engine defined in claim 1 in which the intake and exhaust ports are located in the peripheral wall of the stator.

9. The rotary engine defined in claim 1 in which the intake and exhaust ports have valves for opening and closing such ports and means for controlling the operation of the valves.

10. The rotary engine defined in claim 1 which has ignition means for igniting fuel in each working chamber.

11. The rotary engine as defined in claim 1 in which the outer surface of the rotor is in rolling contact with the vane when the chamber pressure is near maximum.

12. The rotary engine defined in claim 1 which has at least one nonworking chamber for cooling.

13. The rotary engine defined in claim 1 in which the eccentric occupies substantially less than the space defined by the inner surface of the rotor.

14. The rotary engine defined in claim 1 in which the eccentric is counter-balanced within the space defined by the inner surface of the rotor.

15. The rotary engine defined in claim 1 including means in the end walls for guiding and supporting the vanes.

16. The rotary engine defined in claim 1 in which the engine is operated in a four cycle mode of combusion, exhaust, intake, and compression.

17. The rotary engine defined in claim 1 including a power shaft mounted to the eccentric along the stator axis.

18. The rotary engine defined in claim 1 in which the end walls are parallel to each other and perpendicular to the inner surface of the peripheral wall.