US2181705A

US2181705A - Engine

Info

Publication number: US2181705A
Application number: US212222A
Authority: US
Inventors: Andre J Meyer
Original assignee: MAWEN MOTOR CORP
Current assignee: MAWEN MOTOR Corp
Priority date: 1938-06-07
Filing date: 1938-06-07
Publication date: 1939-11-28
Anticipated expiration: 1956-11-28
Also published as: FR855836A; GB530691A

Description

Nov.v 28, 1939. A. J. MEYER 2,181,705

ENGINE Filed June '7, 1938 2 Smets-Sheet l l 1 VENTOR. BY y@ Nov. 28, 1939.

A. J. MEYER 2,181,705

ENGINE Filed June 7' 1958 2 Sheets-Sheet 2 j 4 ATTORNEY.

Patented Nov. 28, 1939 PATENT OFFICE ENGINE Andr J. Meyer, Lexington,

Ky., assigner to Mawen Motor Corporation, New York, N. Y., a corporation of/Delaware Application June 7, 1938, Serial No. 212,222

21 Claims.

The present invention relates to internal combustion engines 4and has particular reference to 'radial cylinder engines of the vkind in which iiow of gases either4 to or fromthe cylinder, or

5 both, is controlled by ports arranged in anannular valve member encircling the cylinder bank and between which and the bank there is relative rotary movement.

Inengines of this kind both the valve member and thev cylinder bank may rotate, but at different speeds, around a stationary crankshaft, or the valve member may be stationary with the cylinder bank and crankshaft rotating but at different speeds. In the type in which both cylinder bank and crankshaft rotate, they. may rotate either in the same or" opposite directions. For numerous reasons not germane to the present in vention, the type in which the valve member is stationary and the cylinders and crankshaft turn in opposed directions is ordinarily to be preferred and the present invention will be described in its application to this particular type. fFor convenience it will be referred to as a bi-rotary engine, the term blrotary, however, being understood to be generic to all types of engines of thev kind in which there is relative rotation between a cylinder bank and an encircling annular valve member.

In the bi-rotary engine as well as in other types, the eiiiciency of the engine and the power capacity depend among other things uponl the efficiency with which spent combustion gases are scavenged from. the engine cylinders and replaced with charges of fresh combustion gases.'

From the standpoint of volumetric efficiency, the

bi-rotary engine is superior to many other types of engines, largely because of the comparatively -large and free "port areas through which it is possible to introduce and exhaust gases from the o cylinders. The nature of the/porting which permits this relatively free flow of gases to Aand from the cylinders'introduces however, certain special factors inuencing the gas flow which are not present in'other types of engines.

'I'he general object of the present invention is to provide for'improved gas iiow, particularly to the cylinders of engines ofthe kind under dis'- cussion, through theprovision of improved valve porting, particularly inlet valve porting.. The

manner in which the above general object and other and more detailed objects of the inventionmay be attained and the advantages to be derived from utilization of structure embodying? the invention will best be understood from a consideration of the ensuing portion of this speciiiq bearings is indicated at:2l and the ,othenat 2l.

cation descriptive of apparatus embodying the invention, taken in conjunction with the accompanying drawings in which: j

Fig. 1 is a fragmentary'sectional longitudinal section showing part of an engineembodying the ,5-

invention;

. Fig. 2 is an elevation looking from the right of Fig. 1, part of the figure being sectioned on the Figs. 5 to 10, inclusive, are sections taken along the radial lines numbered respectively l to I0 in Fig. 4; a Figs. 11'to 14 are sections taken on the respec- 20 tively numbered section lines of Fig. 5; and

Fig. 15 isa view from below of the-inlet porty shown in Fig. 3. A

Referring now more particularly to Figs. l and 2, the engine illustrated comprises a single bank 25 of radially arranged cylinders I0.' Seven cylinders have been shown in this embodiment but it will be understood that the number of cylinders per bank may be varied and valso that engines embodyingthe invention may be constructed 30 with a plurality oi.' cylinder banks.

Cylinders I0 are secured at their inner ends to a crank case structure indicated generally at I2 and advantageously constructed of two crank case parts or halves bolted together as indicated 35 in Fig. 1. The crank case structure is rotatably motmted on bearings Il and I6 to revolve about a crankshaft i8-havin`g a crank pin' 2liP and mounted for rotation in a stationary structure indicated generally at 22. One ofthecrankshaft In the embodiment illustrated, one of the pistons 28 is connected by means aof a master connecting rod 30 to the. crank pin 20: and the remaining pistons of the bank are connected by -45- means of rods 32 pivoted at their inner ends to the inner endI 'of the master rod 30, in known manner.4 In so i'ary as the present invention is concerned, other known forms of connection between pistons and lcrank pin may be employed. w The cylinders and crankshaft in the illustrated embodiment both rotate with respect to the stationary structure 22 and further rotate in opposite directions. The desired rotation of these components of the engine is obtained in the Fig. 4 is a section taken on the lof. i5 v sealing elements and the cylinders and the ing elements are maintained inl sealing contact present instance through the medium of gearing comprising a crankshaft gear 34 meshing with a` gear 36 fixed on shaft 38 journaled at 40 and 42 in the stationary mounting structure. Shaft 40 in the present instance constitutes the power take-oli shaft. Fixed on shaft 38 is a second gear 44 meshing with an idler gear 46 located behind the plane of Fig. 1 andalso carried by the stationary mounting structure. Idler 46 meshes with gear 48 which is fixed to the crank case structure of the cylinder bank.

The stationary housing structure 22 includes an annular valve member 50 encircling the ends of the cylinders, this valve member being provided with peripherally spaced inlet and exhaust passages hereinafter to be more fully described. In the engine illustrated, having seven cylinders and arranged for opposite rotation of the cylinder bank and the crankshaft, the number of inlet and exhaust passages required is four each, the inlet passages being indicated generally at 52 and thel exhaust passagesat 54 the valve member of a suitable exhaust manifold 1 'I'he inlet passages open outwardly of the valve. member where suit- (not shown). from the side able anged seats 58 are provided for the seating of the ends of the radially extending arms 60 of the inlet manifold which is connected with 'carbureter 62.

Other manifolding arrangements may be employed within the scope of the present invention, which, as will hereinafter more fully appear, is concerned primarily with the configuration of the valve ports and the portionsv of the passages in the valve adjacent to the ports.

'Ihe valve member 58 is formed with an inner bearing or sealing face 64 which is preferably spherically curved as indicated. 'I'he outer ends of the cylinders are open and provide cylindrical bores for the reception of sealing elements.66 which preferably are in the form of annular cufflike members having sleeve portions mounted for both rotary and axial movement relative to the cylinders and flanged ends having spherically curved sealing surfaces 68 in sliding contact with the sealing surface of the valve member. Sealing rings similar to piston rings are preferably provided between the telescoping parts of the sealwith the surface of the valve by centrifugal force, preferably aided by springs (not shown) interposed betweenA the ends of the cylinders and the flange portions of the cuiis.

VIn order to seal the valve ports when they are not in registry with the cylinders, an inner sealing ring indicated generally at 'luis provided. 'In the embodiment illustrated, this inner sealing ring is made up of a series of segments or shoes 'l0' eachv having a central circular opening in which the outer end ofthe cylinder, and also .the sealing cuif with which it is associated, are located. The outer faces of the shoes 'l0' are also spherically curved to provide sealing surfaces in sliding contact with the inner surface of the valve member.

' (The several shoes 'l0' are, like the sealing cuffs, held in sliding contact with the face of the valve member by centrifugal force which may be aided by suitable springs (not shown) lnterpOSed between the shoes and the cylinders and acting to force the shoes in radially outward direction. In so far as the present invention is concerned, the construction/of the inner sealing ring may.T be widely varied and may consist; of a single in" tegral ring having a series of openings fori` the reception of the outer ends of the cylinders and the sealing cuffs.

The general type of engine just described is jknown and its general mode of operation will be largely evident from the drawings. gine illustrated, the cylinder bank rotates in clockwise direction as viewed in Fig. 2 and through the gearing connecting the cylinder bank with the crankshaft the latter is made to rotate in the opposite direction. The engine shown is In the enof the four-cycle type and as will be apparent y of the pistons and an exhaust passage 54 through which the spent gasesare discharged. The desired timing of the engine is effected through choice of suitable gear ratio for the gearing connecting the cylinder bank and the crankshaft, which may readily be computed by known methods which need not be described herein.

In so far as the present invention is concerned, the means by which ignition is effected is not material. 'I'he engine may be operated with compression ignition or with ignition effected by any suitable form of ignition means of known character such asl high tension electric spark, glow plug, or the like. n

As will be evident from Fig. 2, the sealing element 68 associated with each cylinder provides a cylinder port 'l2 through whichfresh charges of combustible gas (or air in case the engine'is of the injection type rather than the carbureter type as herein illustrated) and exhaust gases iiow. The cylinder port thus constitutes in effect both an inlet passage and an outlet passage;

'Ihis port' registers with the gas passages in the valve member bypassing them in peripheral directlon and in accordance with the present invention, improved gas iiow to and from the cylinder, particularly to the cylinder, is provided by the special form and configuration of the -passages and ports in the valve member as will now be described more particularly with reference to Figs. 3 to 15. I n Fig. 3, the direction of relative rotation of the cylinder port 12 with respect to the valve member 50 is in the direction of the arrow 14, and the portion of the cylinder port which is in advance in the direction of this relative movement will for convenience be hereinafter referred to as the `leading edge or portion of the port while the portion at the opposite sideof the port will be referred to as the trailing edge or portion of the port. Similarly, the edges of the ports in the valvemember which are first passed by the cylinder port will be referred l accelerated flow of the incoming gas, so that at` least the rst portion of the charge to enter the cylinder does'so at very high velocity. This can to a certain extent be accomplished by narrowing in lateral direction the leading portion of the inlet port opening but the preferred construction provides a web or baiile 16 at the inner end of the, inlet passag 52, whichgweb extends transversely of the passage to provide a main inlet port 18 and an auxiliary inlet port 80. As will be seen from Figs, 3 and 5, the auxiliary inlet port is materially smaller in area than the main inlet port and theauxiliary port is in advance of or leads the main port with respect to the sequence of registration with the cylinder port. -In the embodiment illustrated, the cylinder port 12 is circular in cross-section and the main inlet port is advantageously formed with its leading and trailing edges, 82 and 84 respectively, curved to the same radius as that of the cylinder port. As

will be seen from Fig. 5,1hese curved edges are` curved in opposite directions and inwardly of the port. The leading and trailing edges 86 and 88, respectively, of the auxiliary port 80 are likewise advantageously curved to the same radius as that of the cylinder port but these edges are preferably, as will be seen from Fig. 5, curved in the -same direction to provide an arcuate port separated from the main port by the web 16.

As previously noted, theinlet passage 52 is curved laterally to emerge from the side of the valve member and the general configuration of the passage will be clear from the several sections shown in Figs. 4 to 14. 'I'he inlet passage 52 in the valve does not necessarilyhave to emerge from the side of the valve member and its specific configuration may vary widely within the scope of the invention, There are, however, certain characteristics which should be included in the design of the passage if full advantage is to be taken of the principles of the invention. As will be noted from Figs 3 and 5 to 8, the baflie 16 extends in generally radial direction and the portion 52' of the wall of the inlet passage which lies in front of the baille is curved in the plane of rotation to deflect the inwardly travelling gases so that they tend to enter the cylinder port in a direction along a chord of the circular orbit of movement of the cylinder port. 'I'he orientation of this chord is such that the direction of. ow which the walls of the auxiliary inlet passage tend to impart to the inf-lowing gases may be said to have a radial component and a tangential component in the direction of rotation of the cylinder; port Arelative to the valve member. This direction of ow of the gas when the cylinder port first comes into communication with the leading portion of the valve port is highly desirable whether a baille is employed or not.

As will be observed from Fig. l5, the exhaust port 9U of the embodiment illustrated also has arcuate leading and trailing

edges

92 and 94, respectively, which are curved to the same radius of curvature as the cylinder port, both of these edges being curved in the same direction. Also, the leading and trailing portions 54' and 54 of the wall of the exhaust passage are advantageously curved in the plane of rotation, as appears more clearly from Fig. 3, so that the outowing gases are given a direction of flow which has a tangentialcomponent in the direction of relative rotation of the valve member with respect' to the cylinder bank.

It is to be noted particularlyrwith respect to the leading and trailing edges of the ports in the valve member that the trailing edge 54" of the exhaust port 54 is curved to register with the trailing edge of'the cylinder port while both the leading and trailing edges of the auxiliary inlet port are curved of the cylinder port, and the trailing edge of the maininlet port is curved to register with the trailing edge of the cylinder port. The configuration of the above port edges is more important than the configurations of the leading edges of the exhaust port and the main inlet port.

As will be observed from Fig. 3, the distance betweenthe trailing edge of the exhaust port and the leading edge of the auxiliary inlet port is less` than the diameter of the cylinder port so that the cylinder port is temporarily in communication with both inlet and exhaust. In other words, there is overlap of the timing of inlet and exhaust. vWith the port arrangement and construction as above described, the action with respect to admission and exhaust of gas to and from the engine cylinder is as follows, commencing with the exhaust portion of the cycle: Before bottom dead center of the piston on the working stroke is reached, the cylinder port comes into communication with the leading edge of the exhaust port, the sealing element or cui '66 being f to the left of the position shown in Fig. 3. As

the cylinder port moves relative to the valve member 50 in the direction of the arrow 14 during the ensuing upward exhaust stroke of the piston, full registration between exhaust ports is eiected and the area. of the exhaust port in communication with the cylinder is thereafter decreased as the cylinder port moves to the position shown in Fig. 3. In order to prevent the pressure of the gases from droppingr to the pressure in the exhaust manifold too early in the cycle, which would tend to reduce the velocity of outflow later in the Dexhaust stroke, the leading portion of the exhaust port may in some instances advantageously be narrowed in lateral direction to somewhat restrict the outflowI during the early portion of the exhaust period. During the exhaust period the gases leave the cylinder atlhigh velocity and this high velocity outflow continues in the trailing portion of the cylinder port after the cylinder port comes into communication with the inlet. When the exhaust gases flow at high velocity from the cylinder during the latter part of the exhaust stroke they are capable of producing sub-atmospheric pressure in the cylinder when the piston is near top dead center and Athis aids in the induction of fresh gas into the cylinder by establishing a pressure differential between the interior of the cylinder and the inlet passage. 'Ihe higher the velocity of outflow at the end of the exhaust stroke the higher this pressure diierential becomes and the desirable condition of thigh outilow velocity is contributed to by the phase of the present invention which provides the curved trailing wall portion ofthe exhaust passage, andthe curved trailing edge of the exhaust port, which is shaped to register with the trailing portion of the cylinder"` port. This shaping of these portions of the exhaust port and passage result in substantial elimination of eddy currents, particularly at the important time late in the exhaust stroke when the' exhaust port is being closed, and consequently maximum speed of egress of the gases at this time is insured.

In the case of an engine which is not supercharged, the pressure diierential between the cylinder come into communication provides a means for inducing the ow of fresh gas into the cylinder to registerI with the leading edge the cylinder and in the cylinder/15 and the inlet passage at the instant they Y and this pressure differential may further be enhanced by delaying opening ofthe inlet port until appreciably `after the piston has passed top dead center and is moving downwardly on the suction stroke. By providing a substantial pressaure differential between cylinder and inlet passage when the inlet is rst opened and further by shaping the leading portion of the inlet passage so that the velocity of the incoming'gases in this portion of the passage may be smoothly accelerated, relatively very high velocity of the initial portion of the incoming charge can be obtained even with' an unsupercharged engine. Further, by directing this high velocity initial portion of the incoming charge toward the leading portion of the cylinder port passage, and

enging the cylinder of the residual portion of spent combustiongases. By directing the inowing gases in the manner stated, this scavenging action is obtained with sidual spent gas with the incoming fresh gas.

In the case of a supercharged engine, the positive pressure produced of course, provide ample pressure differential between the inlet passage and the cylinder, but even in the case of a supercharged engine, the direction of ow of the incoming'gas into the cylinder port is important in order to'avoid mixing of fresh and spent gases in lthe cylinder and the shaping of the portion of the inlet port which opens first and of the leading portion of the inlet passage is also of importance in securing high velocity admission of the initial portion of the incoming charge, which in eect acts as a scavenging jet for forcing from the cylinder theV last of the residualgases. u

The small area of the auxiliary port, which resultsl among other things in the high initial velocity imparted to the incoming gases, would, if it constituted the sole inlet, adversely affect the volumetric eii'iciency of the engine but any tendency for the volumetric efficiency of the engine to be reduced by the restricted area of the inlet port is, of course, negativedby the ample area of the main inlet port with which the cylinder port comes into registry substantially immediately after registry with the auxiliary port and preferably as soon as thecylinder port has passed out of communication with the exhaust port.

Because of the fact that the trailing edge of the exhaust port is shaped to register with the trailing edge of the cylinder port, quick closing of this port with minimum wire drawing effect is obtained and the curvature of the leading and trailing wall portions of the exhaust passage 54 serves to minimize turbulence in the outflow- ,ing gases, both of these factors contributing to the eiiiciency with which the cylinder is emptied of the spent gases.

The curvature of the leading and trailing edges of the auxiliary inlet port so that these edges register with the leading edge of the cylinder port, results in an advantage which will be obvious from the preceding explanation Since such curvature not Ionly results in very quick opening of this port, but also serves to direct the incoming gas in a manner which' avoids to the greatest extent any intermingling between fresh and spent gas.

By curving the trailing edge of the main inlet port to register with the trailing edge of the cylinder port, the inlet port is, like the exhaust port,

minimum mixing of reby the supercharger will, o

'register with the trailing edge portion of the cylmetric eciency.

-It will be .evident from the foregoing that with the port arrangements employed in accordance with theprinciples of the present invention, highly eicient scavenging of the engine cylinders may be effected even in the case of unsupercharged engines. The specific timing of the opening and closing of the ports will vary with different specic engine designs, but by way of' example the following may be stated as suitable for the specific port arrangement hereinbefore described, in an engine suitable for automotivey use and having a -normal maximum operating 1 speed of the crankshaft relative to the cylinder bank of the order of 3,000 R. P. M.:

nExhaust opens 45 before bottom dead center.

It will further be evident that in so far as the present invention is concerned, different specic 2. combustion cycles may be employed and the term "gas" as herein employed is to be considered to include any gaseous'medium inducted into the cylinders, whether such medium be a combustible gas, or air or other combustion supporting medium to which fuel isfadded in the cylinder.

With different combustion cycles, certain phases of the present invention will be more important than with other combustion cycles and it is accordingly to be understood that the invention `\'s not limited in its scope to the arrangementl shown vand described herein by way of example but may be embodied in other specific forms of construction which may employ all of the features of the invention or may utilize some to the exclusion of others. The scope of the invention is to be considered as embracing all forms of structure falling within the purview of the appended claims when they are construed as broadly as the state of theprior art permits.

What I claim is:

1. In a bi-rotary engine, a cylinder bank including a cylinder having a port at its outer end, and an annular valve member having an exhaust gas passage extending therethrough, said passage terminating at .its inner end in an exhaust port, said exhaust port being located so as to be brought into and out of communication with the cylinder port by relative rotary movement between the cylinder bank and the valve member, the trailing portion of the wall of said exhaust passage being shaped to direct the utfiowing gases after they leave the cylinder port in a direction having a tangential component in the direction of relative movement of the valve member with respect to the cylinder bank.

2. In a bi-rotary engine, a cylinder bank including a cylinderhaving a port at its outer end, and an annular valve member having an exhaust port located to be brought into and out of communication with the cylinder port by relative rotary movement between the valve member and the cylinder bank, the trailing edge portion of the exhaust port being shaped to substantially 70 inder port and the leading edge portion of the exhaust port being shaped to a different contourfrom that of the leading edge portion of the cylinder port so that said leading edge portions are not in registry as the ports come into com- 75 whereby to provide less rapid opening of the exhaust ports than closure thereof.

3. In a bi-rotary engine, a cylinder bank including a'cylinder h aving a port at its outer end, and an annulary valve member having an exhaust port therein located to be, brought into and `out of communication with the by relative rotary movement between the valve member and the cylinder bank, the leading and trailing edge portions of said exhaust port being shaped relative to therleading and trailing edge portions, respectively, of the cylinder port to provide for slower opening of the exhaust port as the ports come into communication with each other than closure thereof as the ports pass out of communication with each other. 4. In a bi-rotary engine, a cluding a cylinder 'having a port at its outer end, and an annular valve member having an exhaust niunication,

port therein located to be brought into and out of y communication with the cylinder port by relative rotary movement between the valve member and the cylinder bank, said cylinder port being gen- A erally symmetrical with respect tothe axis of the cylinder and the leading portion of the exhaust port being narrower in lateral direction than the trailingportion thereof.

5. In a bi-rotary engine, a cylinder bank including a cylinder having a port at its outer end, and an annular valve member having an exhaust gas passage extending therethrough, said passage terminating at its inner end in an exhaust port located to be brought into and out of communication with the cylinder port by the relative rotary movement between the valve member and the cylinder and trailing portions of the wall of said exhaust passage being shaped to direct the outflowing "gases after they leave the cylinder portin a direction having. a\ tangential component in the direction of relative movement of the valve member with respect to the cylinder bank.

6. In a bi-rotary engine, a cylinder bank including a cylinder having a passage terminating at its outer end in a cylinder port, an annular an exhaust port and an inlet port therein adapted-to be brought into communication with the cylinder port in the order named by relative rotary movement between the valve member and the cylinder bank, said exhaust port and said inlet port being located to be in overlapping communication with the cylinder port and the inlet being shaped to direct a high velocity stream of inflowing gas in a direction tending to confine it to 'the leading portion of the cylinder port passage during the period of overlapping communication ofthe ports.

'7. In a bi-rotary engine; a cylinder bank including a cylinder having a passage terminating at its outer end in ay cylinder port, and an annular valve member having an inlet passage therein each terminating in a said valve ports being located to bring said-passages into communication with the cylinder port in the order named by relative rotary movement between the valve member arid the cylinder bank, the spacing between said inlet L and exhaust ports being such that overlapping communication is established with the cylinder port and theleading yportion of the wall of said inlet passage being formed to direct the inowing gas in a direction tending to confine it to the leading portion of said cylinder passage during the period of overlapping communication between said ports.

cylinder port.

cylinder bank inbank and the leading,

an exhaust passage and 8. In a bi-rotary enginea cylinder bank including a cylinder having a cylinder port at its tween the valve member and the cylinder bank,

the spacing between said inlet and exhaust ports being suchj that overlapping communication is established with the cylinder port, and the leading portion of the wall of said inlet passage being rormed to direct the inowing gas into the cylinder port in a 'direction having a tangential component in the direction of relative rotation of the cylinder bank with respect to the valve mem-v ber.

9. In a bi-rotary engine, a cylinder bank including a cylinder having a cylinder port at its outer end, and an annular valve member having an exhaust passa/ge andan inlet passage therein each terminating in a valve port, said valve ports being located to bring said passages into communication with the cylinder port in the order named by relative rotary movement between the valv member and the cylinder bank, the spac- -ingv between said inlet and exhaust ports being suchl that overlapping communication is estab- `lished with the cylinder .port and the leading portion of said inlet passage adjacent to the inlet port being shaped to accelerate the velocity of the gas iiowing into Lthe cylinder when the cylinder port rst communicates with the inlet.

10. In a bi-rotary engine, a cylinder bank in` cluding a cylinder having a port at its outer end, and an annular valve member having an eX- haust port and a main inlet port located to be brought into communication with the main cylinder port in the order named by relative rotary movement between `the cylinder bank and the valve member and an auxiliary inlet portflocated between said exhaust port vand said, main inlet port.

l1. In a bi-rotary engine,.a cylinder bank including a cylinder having aport at its outer end, and an annular valve member having an exhaust port and a main inlet port located to be brought into communication with the cylinder port in theforder named by relative rotary movement between the valve member and the cylinder bank, and "an auxiliary inlet port located between said exhaust port and said main inlet port, said auxiliary port being 'spaced from the exhaust port to provide overlapping communication between the cylinder port on the one hand and the exhaust port and said auxiliary port on the other hand.

l2. In a bi-rotary engine, a cylinder bank including a cylinder having a port at its outer end, an annular valve member having an exhaust port and a main inlet port located to be brought an annular valve member having an exhaust port and a main inlet port located to be brought into communication with the main cylinder port in 15 adjacent to the inner end thereof to provide an auxiliary inlet port anda main inlet port located to be brought into communication with the cylinder port in the order named by relative rotary movement between the valve member and the cylinder bank.

15. In a bi-rotary engine, a cylinder bank vincluding a cylinder having a port at its outer end, an annular valve member having an inlet passage extending therethrough and a baille located in said passage to provide an auxiliary inlet port and a main inlet port located to be brought into communication in the order named by. relativeV rotary movement between the valve member and the cylinder bank, said baille and the leading portion of the wall of the inlet passage being shaped to provide an auxiliary inlet port opening the lateral extent of which is several times the length of the opening in the plane of rotation.

16. In a bi-rotary engine, a'cylinder bank including a cylinder having a passage terminating at its outer end in a port, an annular valve member having an inlet passage extending therethrough and a baiile in said passage providing an auxiliary inlet port and a main inlet port arranged to be brought into communication with the cylinder port in the order named by relative rotary movement between the valve member and the cylinder bank, the leading portions of the edges of said auxiliary inlet port and of said main inlet port being shaped to register with the leading portion of the edge of the cylinder port as the respective valve ports come into communication with the cylinder port.

17. In a bi-rotary engine, a cylinder bank including a cylinder having a passage terminating at its outer end in a port, an annular valve member having an inlet passage extending therethrough and a baie in said passage providing an auxiliary inlet port and a main inlet portarranged to be brought into communication with the cylinder port in the order named by relative rotary movement between the valve member and the cylinder bank, the leading portion of the edge of said auxiliary port being shaped to register with the leading portion of the edge of the cylinder port as the ports come into communication and the trailing portion of the edge of the main inlet port being shaped to register with the trailing portion of the edge of the cylinder port as the ports move out of communication.

18. In a bi-rotary engine, a cylinder bank including a cylinder having a cylindrical passage at its outer end terminating in a cylindrical port,

an annular valve member' having' an exhaust port,

an auxiliary inlet port, and a main inlet port 1o.

cated to' be brought into communication with the cylinder port in the order named by relative rotary movement between the valve member and the cylinder bank, said auxiliary inlet port being arcuate in form and arranged to register with the leading portion of the cylinder port as these ports come into communication and further being located with respect to the exhaust port so that the exhaust port and the auxiliary inlet port are in overlapping communication with the cylinder port, and the trailing portion of the edge of the exhaust port being shaped to register with the trailing portion of the edge of the cylinder port as communication between the two latter ports is closed.

19. In a bi-rotary engine, a cylinder bank lncluding a cylinder having a circular port at its outer end, and an annular valve member having an exhaust gas passage extending therethrough, said passage terminating at its inner end in an exhaust port located to be brought into and out of communication with the cylinder port by the relative rotary movement between the valve member and the cylinder bank, the leading and trailing edge portions of said exhaust port beingsubstantially parallel to each other, and curved to substantially the same radius of. curvature as said circular cylinder port, and the direction of curvature of said trailing edge portion being such that the trailing edge-portion substantially registers with the trailing edge portion of the cylinder port as the ports pass out of communication with each other. I

20. In a bi-rotary engine, a cylinder bank including a cylinder having a port at its outer vend, and an annular valve member having an exhaust gas passage extending therethrough, said passage terminating at its inner end in an exhaust port located to be brought into and out of communication with the cylinder port by the relative rotary movement between the valve member and the cylinder bank, the leading and trailing portions of the wall vof said exhaust passage being curved in the plane 'of rotation, and the direction of curvature thereof being such as to direct the outowing gases after they leave the cylinder port in a direction having a tangential component in the direction of relative movement of the valve member with respect to the cylinder bank.

21. In a` bi-rotary engine, a cylinder bank including a cylinder having a port at its outer end, an annular valve member providing an auxiliary inlet port and a main inlet port located to be brought into communication with the cylinder port in the order named by relative rotary movement between the valve member and the cylinder bank, there'being an inlet passage formed in said valve member communicating With said auxiliary inlet port, and the walls of said passage converging in the direction of ow of the gases through the passage to accelerate the ow thereof and increase `the velocity of delivery thereof from said auxiliary inlet port.

lANDR J. MEYER.

Leas