CA2180198C - Axial vane rotary engine with continuous fuel injection - Google Patents

Abstract

An axial vane rotary device (14) includes a stator (16) with a cylindrical internal chamber (34) defined an annular outer wall (40) and two side walls (36, 38) of the stator. Each side wall has an annular cam surface (42, 44). A rotor (54) is rotatably mounted within the chamber. The rotor has an annular outer wall (66) and a plurality of angularly spaced-apart, axially extending slots (64) extending therethrough. A vane (68) is slidably received in each slot. The vanes reciprocate axially and alternatively expand and compress spaces between adjacent vanes and the cam surfaces as the rotor rotates. The cam surfaces have alternating first portions (92) and second portions (90). The second portions are further from the rotor than the second portions. The first portions of one said cam surface are aligned with second portions of another said cam surface. The outer wall of the stator may have a guide cam (96) and the vanes may each have a follower (98) received by the guide cam. The guide cam is shaped to cause the vanes to reciprocate axially with respect to the rotor as the rotor rotates. There is a fuel injector which continuously injects fuel into the chamber during each complete revolution of the rotor. There may be 12 or 16 vanes on each rotor.

Description

~ ~ 2180~98 .
AXIAL VANE ROTARY ENGINE WITH CONTINUOUS FUEL INJECTION
BACKGROIJND OF THE INVENTION
Field of the Invention This invention relates to rotary engines of the axial vane type, particularly the class of devices where volume change occurs between relatively close vames and cam surfaces on each side of the rotor and where tll~ vanes translate axially relative to the rotational axis of 10 therotor.
Description of Related Art Many different types of rotary engines have been suggested in the past and have been 15 covered by a large number of patents. Only a relatively small number of these have been thoroughly tested. Many rotary engines are appealing on paper, but practical difficulties arise when prototypes are constructed.
The best known rotary engine is the Wanlcel engine which is in volume production in Mazda 20 ~ m--hilP~ Even this engine has had considerable difficulties with proper sealing of tlle rotors, although such problems have been largely overcome. Elowever, the engine is not I~ly efficient and high fuel consumption is a . I.,..,~ IP, ;~ of vehicles using this technology.
25 Another type of rotary engine is referred to herein as the "axial vane type". This type of engine has a cylindrical rotor located within a cylindrical chamber in a stator. A plurality of blade-like vanes extend slidably through the rotor, parallel to the axis of rotation. There are undulating cam surfaces on each side of the rotor. High portions of the cam surface on one side align with low portions of the cam surface on the other side such that the vanes are 30 caused to reciprocate back and forth in the axial direction as the rotor rotates.

218~198 .

One such engine is found, for example, in United States Patent No. 4,401,070 by James Lawrence McCann. This type of engine compresses gases forwardly of each vane in tlle di}ection of rotation as the rotor rotates. The compression occurs as the vane moves from a low cam surface, relatively dist~nt from the rotor, to a hign cam surfæe relahvely close the 5 rotor. After the gases are compressed, tl1ey must be transferred to the rearward side of ~ach vane prior to ~mh~ \n so tna~ the ignited gases will propel the rotor forwards.
The need for ~"~ rc";l,~ the l,ULUlJlCi~ ,d gases is removed in a variation of this type of rotary engine such as found in Polish Patent No. 38112 to Czyzewslii. In this case, the gases 10 are compressed between adjæent vanes which are angularly spaced-apart much closer than in the McCann engine. The gases are ~u~ c~i~cd as each pair of adjacent vanes moves towards a high cam area. Expansion of the ignited gases is permitted, and the propulsion force created, as the vanes continue to move past the high cam area to a relatively low cam area after ignition.
This type of rotary engine offers many potential advantages including high efficiency, simple ~ulL~L ucLiull and light weight. However, while the theoretical possibility of such an engine has been suggested in the past, many practical difficulties have inhibited Icvcluplllcllt of such en~ines beyond the stage of a worl~ing prototype. For example, considerable time and 20 effort have been expended trying to develop practical sealing systems between the vanes, the rotor and the stator of such an engine.
Fu, llc~ u~;; the rotational speed of such engines has been limited in some instances by fuel injectors which can only pulse on and off at a flnite rate.
Rotary engines of the axial vane type typically operate on a four stroke cycle. However the entire four stroke cycle is repeated by each vane upon each complete rotation of the rotor.
In other words, the engine uses only 360 of rotation to do what a ~ U~.Lil,~ engine does 218~19~
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in 720. In short, each degree of rotation of such an engine is equivalent to t~vo degrees of rotation of a ~ U-,aLill~ engine.
Applying this lûgic, a compression ignition rotary engine of the type would optimally start S fuel irljection ât lO~BTDC with an injection duration of 15 because a typical l~ i,ulu~,aLillg diesel engine starts injection at 20BTDC and ends fuel injection at 10ATDC for a total injection duration of 30. The total injection duration of an equivalent rotary engine wûuld therefore be 15.
10 Prâctical experience with rotary engines however shows that such engines optimize with longer fuel injection durations which tal~e about 30 of their shaft rotations. In other words, these engines typically take a larger percentage of their cycle to inject the fuel. This is because such engines typically operate with hotter combustion chamber walls and have shorter ignition delays and faster burning rates. The shape of the volume versus crankshaft 15 angle curve allows more time at minimal volumes for the ~r~nnh~ ion to take plæe.
Some previous rotary engines of the type have been provided with eight vanes and are designed for an injection duration of 30. This meant that each chamber was in position under the injection nozzle for 45 shaft degrees. The injection took place up to two thirds of 20 this time. This means cycling the injectors offand on at a rate equal to the number of vanes times the rotational speed of the engine.
It is an object of the invention to provide an improved axial vane rotary device which overcomes the d;~alva~ associated with earlier engines of the type.
It is another object of the invention to provide an axial vane rotary device which has a simplified ~ " ,. .l ;. " . without complex sealing systems between the vanes, rotor and stator.

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It is a further object of the invention to provide an improved axial vane rotary device with a simplified fuel injection system which does not limit the rotations speed of the engine.
It is a still further object of the invention to provide an improved axial vane rotary device 5 ~hich is practical to produce, relatively low in cost and durable.
SUMMARY OF THE INVENTION
In accordance with these objects, tllere is provided an axial vane rotary engine which 10 includes a stator having a cylindrical internal chamber defined by an annular outer wall and two side walls of the stator. Each side ~vali has an annular cam surface. There is a rotor rotatably mounted within the chamber having an annular outer wall and a plurality of angularly spaced-apart, axial slots extending Lh~ U.1VU~II. There is a vane slidably received in each slot. Each vane has an outer edge, am inner edge and side edges. The side edges 15 slidably engage the cam surfaces. There is means for al~ ld~iv~ly expanding and co~ g spaces between adjacent said vanes and the cam surfaces as the cam rotates.
This means includes alternating first portions and second portions on the cam surfaces Tlle second portions are further from the rotor than the second portions. The first portions of one cam surface are aligned with the second portions of another said cam surface. There is 20 means for ~ .."l; ", .... ,~ly injecting fuel into the chamber during each complete revolution of the rotor. The means for injecting is at a position to inject fuel between each pair of vanes as tlley rotate past the fuel injecting means.
In one example of the invention, there are t~velve vanes spaced-apart about the rotor at 30 25 intervals. Alternatively there may be sixteen vanes which are 22.5 apart.
Sigmficarlt advantages are achievable by utilizing continuous injection. The injectors do not have to turn offand on at all. This simplifies the nature of the injectors amd means that the rotational speed of the engine is no longer limited by the response time of the mjectors to ., " 2l8ol98 .

turning on and off. With a twelve vane engine, locating the fuel injection nozzles at TDC
results in an effective beginning of injection timing of 15BTDC and an effective injection duration of 30. Control of engine power output may be d~,coll~ cd by controlling the pressure applied by to the nozles with power mcreased by simply raising the fuel pressure.
s Alternatively, a sixteen vane engine will shorten the effective injection duration to 22.5 which may result in an even better combustion efficiency. The twelve and sixteen vane a~nfigllr~ti--nc result in zero thrust loads on the bearings.
10 In addition, constant volume combustion is obtained by using the twelve or sixteen vane engine geometry with appropriate dwells on the cans. By this method the time (shdft angle) which it talses for the engine volume to increase from minimum to d~ lcly 5% of maximum volume can be doubled. This gives more time for combustion at any given speed which effectively makes the combustion cycle operate as if the engine speed were actually 15 lower than it is.
Th~ rnmhin~til~n of continuous injection and constant volume r~lmhl l~tir)n has the effect of increasing peak heat flux. The engine can be designed without seals on the vanes, so there is no surface in the combustion chamber which requires lubrication. Therefore it is possible 20 to apply thermal barrier coatings to all surfaces of the ~omh~lcti-.n chamber to reduce the pealc heat flux and the overall heat transfer. These coatings can be applied to the face of the rotor, to the cam surface and to the inner and outer housings. The usually problem of applying thermal barlier coatings to diesel engines is avoided by eliminating its effect on lubrication and by isolating the various E)ortions of the cycle by geometry. The hot area is 25 always hot and the cold area is al~vay cold. The avoids volumetric efficiency ~P~r~ tion due to the hot walls of the ~,mh~l~ti~-n area being exposed to the intake portion of the cycle.

~, 218~1q8 This ~onf ~llrPtion of rotary engine, utilizing continuous injection and constant volume combustion is ideal for incorporation of the Miller Cycle and/or the K-Miller Cycle. There is no sig[uficant siæ penalty imposed by the Miller Cycle because of the very high specific volume of tbis type of rotary engine. Furthermore it is easy to incorporate the K-Miller S Cycle by using multiple intake ports ~vith a simple on/off valve to vary the intake portion closing angle. This feature leads to si~nificant efficiency illl~llOY~lll.,llis including the use of internal . .,,.,l...,l",li.,~ The inherent low heat rejection of the high speed continuous injection engine, along with the additional heat due to the thermal barrier coatings, raises the exhaust energy recovery potential of tlle engine. The æro overlap .~ i. of the ports 10 enables the intake pressure to be significantly higher than the exhaust pressure.
In general, rotary engines according to the invention cam be significantly reduced in complexity and costs compared to some earlier designs. Reliability is increased compared with ;, .f., . I I Irl 1~ t,Ype diesel fuel injection systems. The output power of the engine can be 15 effectively doubled by doubling the speed of tbe engine because there is no upward limit placed by the response rate of the fuel injectors. The maximum rotational speed can now be increased to well over 2~00 rpm.
Other advantages are as follows:
1. Lower cost of urltimed fuel system offsets cost of more vanes.
2. More vames results in lower pumping work losses.
3. There are lower exhaust emissions. Poor combustion from poor quality (low pressure) A~(lmirRtion at the beginning and end of injection are eliminated. This reduces the ll~dl~ lJull and particulate emissions.

4. The higher frequency c~-mhll~tion resulting from more vanes and higher speeds reduces oYerall noise levels. Likewise the rlimin~til)n of the conventional fuel injection nozzles eliminates a major source of structural borne noise caused by the opening and closing of the injector valves.
5. The untimed fuel injection system weighs less than a diesel fuel injection system. Controls are simplified and also weigh less.
6. The engine, particularly in multi-rotor form, is smaller because of the single untimed continuous flow fuel pump instead of two separate pumps for each rotor. The result is a significant length reduction for the engine.
7. There is a significant reduction in the number of critical parts and accordingly this eliminates potential failure from many critical c~ L~. This is pal Li~,ulafly important for aircraft applications.
Examples are potential failures due to sticking or leaking fuel injection nozzles, seized pumping elements and the like. It is also ~0 easy to incorporate redundant systems with two pressure pumps isolated from each otner by check valves.

8. The elimination of the diesel fuel injection pumps and nozzles and their associated high accuracy cam drive malies a significant iUl~JlVr~ in engine durability. The increase in number of vanes to twelve or sixteen results in lower bearing loads and therefore longer bearing life.

,, 2180198 BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. I is a simplified isometric view of an axial vane rotary device according to an bodilll~llL of the invention vvith the stator thereof partly broken away;
Fig. 2 an unfolded geometrically developed view of a fragment of the stator, rotor and four ofthe vanes thereof, showing the position upon ~ iull of the mixture;
Fig. 3 is a view similar to Fig. 2 showing the position upon combustion;
Fig. 4 is ~ ,., . "" ,~ side elevation of the device, Fig. 5 is an unfolded geometrically developed view of the vanes as they traverse one complete revolution within the stator;
Fig. 6 is a sectional view taken along line 6-6 of Fig. 5;
Fig. 7 is a ~à~ Laly top elevation of one of the vanes and portions of the rotor and stator;
Fig. 8 is a Jîa~ll~ll~y side elevation of the vane of Fig. 7 and portions of the rotor and stator;
Fig. 9 is a graph showing volume bet~veen pairs of vanes plotted against sha~t angle for a 12 vane engine and 8 vane engine; and ~ 2180198 Fig. 10 is a (li ~ """ ,~ les.,~ ion of the control system for the secondary intake port for a variation of tlle engine operating on the K-Miller cycle.
DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring first to Fig. 1, this shows an axial vane rotary device which in this example is configured as an engine 14. The engine 14 has a stator 16 which includes a barrel-shaped housin~ 18. Various materials could be used including cast iron, but aluminum is preferred for wei~ht and improved cooling. The housing includes a pair of annular members æ and 24 in this example. Each member has an annular outer wall 26 and an inner wall 28 rotatably supporting a shaft 30 by means of a bearing 32 on each side, one only being shown only in Fig. 1. There is a cylindrical internal charnber 34 within the stator defined by side walls 36 and 38 and annular outer wall 40.
Tllesidewalls36and38haveradiallyoutwardportionsthereofcomprisingcamsurfaces42 and 44 respectively. The cam surfaces in this embodiment form the irlner surface of separate annular cam members 46 and 47.
The cam surfaces 42 and 44 preferably are coated with a slurry type ceramic or cermei 20 coating to prevent wear and reduce friction. The cam members 46 and 47, require precise angular location between the two sides of the engine and the outer housing 18. Dowel pins or other devices are preferably used to give this alignment. This permits the cam surfaces to be separately positioned relative to the sides of the rotor to provide precise control of the gap between tlle side edges of tlle vanes and the cam surfaces 40 and 42.
Clearance can be provided between the cam surfaces and the housing 18. This clearance can be sealed with a pair of metallic circular seals and used to permit local thermal expansion of the cam surfaces. The cam surfaces can be ground machined using a tapered grinding wheel which is tapered so that the point of the taper would be at the center axis of the engine.

A rotor 54, which is generally cylindrical in shape, is installed within chamber 34 and is rotatably supported by the shaft 30. The rotor in this example is a hollow casting that is cast using twelve pie shaped cores for a twelve vane engine or sixteen cores for a sixteen vane engine to make the rotor hollow in the areas between the vanes and are supported by holes S in the side of the rotor.
Referring back to Fig. 1, a vane 68 is slidably received within each of the slots 64. The vanes are caused to reciprocate axially, in the direction parallel to shaft 30, as the rotor rotates. The vanes reciprocate back and forth and slidably engage undulating cam surfaces 42 and 44 as the rotor rotates. In this way, the engine is similar to previous engines of the type.
Tlle vanes have outer edges 74 which slidingly engage outer wall 40 of the stator. This occurs because the slots 64 extend all the way out to the outer wall 66 of the rotor. The outer edge 74 of each vane is machined in this ~Illbodil.l~llL to match the outer wall 40 of the stator. In other words, the outer edge is slightly convex. This reduces crevice volume effects between the vane and outer housing. A separate wear insert piece can be installed over the entire end of the outer edge of each vane to reduce friction and wear. The insert can be simply pressed into a slot in the vane.
As seen in Fig. 1, the engine 1~ has provision for the intake of air at opening 76. Exhaust gases leave the engine tbrough opening 78. Opening 80 admits cooling fluid into the engine, while opening 82 is for the discharge of coolant from the engine. There are ~ ~w~y~ 83 in the stator which carry the coolant in order to cool the engine. The engine also has fuel injectors 84 and 84.1, the latter shown only in Fig. 5, which extend through the stator into the chamber 34. There is one fuel injector on each side of this engine.

2lsalss As described above, the fuel injectors 84 and 84.1 inject fuel f ~ IY into the chamber 34. The space between adjæent vanes dc~vldill~;ly is filled with aeomized fuel as each pair of vanes passes the fuel injector.
There are combustion chambers 1 04 and 1 04.1 on the rotor between each pair of vanes as shown best in Fig. I and 6. In this exarnple the r~mh--cti-~n chambers are arcuate recesses spaced-apart a small dist~nce inwardly from the outer wall 66 of the rotor. The fuel injectors are positioned to sp}ay the fuel into these ~,U~ Liull chambers as seen best in Fig. 6.
Alternatively these combustion chambers can be rounded pockets or the like formed in the wall of the rotor or dlL~ aLi~,'y in the wall of the stator adjacent the rotor.
It should be noted that the engine 14 does not have the complex seals found on the vanes and rotors of some earlier engines of this type. This considerably simplifies the structure of the engine. Such seals do not appear on the engines in some earlier patents, but this is because such engines were actually not reduced to practice and had not been reflned to the point where seals had been designed. However in the present instance seals are not critical. The twelve or sixteen vane engine with continuous fuel injection obviates the need for seals. Any leakage of compression simply goes into an adjacent chamber and does not have a significant, detrimental effect upon the efficiency or operation of the engine.
The operation of the engine is best understood with reference to Fig. 5. As may be seen, this particular engine has twelve vanes identified as 68.1 - 68.12 ~ .,ly. Each side of the engine operates essentially i".l. l~ ,,.l. ..tlY of the other side. Therefore, for ~l,l,.,.,"i,...
2~i purposes, only the left half of the engine, from the point of view of Fig. 5, will be described.
Rotor 54 rotates downwards from the point of view of the drawing. Each side of the engine has a primary intake port 86 through tlle stator which ~l""",.";. - ~ ~ with the opening 76 shown in Fig. 1. Tllere is also a secondary intake port 87 separated from the primary intal~e pûrt by a portion 89 of the stator. Exhaust port 88 ~ .-",.".1.,; ,.IPC with opening 78. The 21801~8 engme is described with reference to degrees of rotation about cam surface 42 starting with O at the top of the drawing. Vane 68.1 is located at 0 while vane 68.4 is a~lu~ aL~ly 90, just prior to intake port 86. As this vane continues to move forward, air received thrûugh primary intake port 86 is trapped between vanes 68.4 and 68.5. More air is taken S in between these vanes as they pass by secondary intake port 87. Tllere is then a period of dwell when the vanes move over the low pûrtion 90 of the cam surface shown between vanes 68.6 and 68.7. Vane 68.7 is shown at 180 at the beginning of the compression stroke. The air between vane 68.7 and vane 68.8 is ~,u~ ,d due to the decreasing volume between the vanes as vane 68.7 moves from low cam portion 90 to high cam portion 92. The low cam portions are further from rotor 52 than the high cam portions.
Il1 a variation of the engine adapted to operate on the Miller cycle the secûndary intake port 87 may be closed by for example, valve 150 shown s~hPm~ti~lly in Fig. 10. The intake process ends when the primary port closes which is before maximum volume is achieved This is early intalse closure timing. This effectively reduces the compression ratio of the engine without affecting the expansion ratio. Miller cycle engines are built with abnormally large expansion ratios which result in significant efficiency illl~lluvc~ La. Normally the UU~ ;Ull ratio equals the expansion ratio which means that excessive compressionpressures and hence excessive peak pressures occur. The Miller cycle limits these peak pressures by early cessation of the intalse cycle and reducing the amount of air trapped in the chamber.
The K-Miller cycle is a variant which allows the timing to be varied such that the higher l,U~ iUII iS allowed during starting and light load operation. The valve 150 closing the secondary port 87 can be controlied by a simple aneroid bellows 152 fed by the outlet pressure of LUIIJOGIIal~t;l UUIII~ UI 154 to allow the port to be open when ~,UIII,UI~ 01 pressure is low and closed when the pressure is high. A conduit 156 connects the compressor to the bellows. A link arm 158, connects the billows to a pivot pin 159 connected to the valve which opens or closes by pivoting about pin 160.

The air between two vanes is further compressed as vane 68.8 moves to the position of vane 68.9 and is fully compressed when they achieve the positions of vanes 68.9 and 68.10 where tl1e two vanes are located over the high cam portion 92. Vane 68.9 is at a 240, while vane 68.4 is at 270. Ignition occurs when the vanes are just past the positions shown and vane 68.9 is at a 255. Fuel is injected by injector 84 of this engine which is configured as a compression ignition engine.
Expansion of the ignited mixture is permitted as the vane 68.10 moves forwardly to the position of vane 68.11. This is the expansion stroke of the engine. The exhaust strolie begins at the position of vane 68.1 at 0. At this point the exhaust gases are located between vane 68.1 and vane 68.2. The exhaust gases are forced out through exhaust port 88 as vane 68.1 moves forwardly, which is downwards from the point of view of the drawing.
The other side of the engine operates in a similar manner, but the positions of the various strokes are stag~ered and follow the sequence of compression stroke, expansion stroke, exhaust stroke and intake stroke from lef~ to right from the point of view of Fig. 5.
Constant volume ~nnnhllcti~n results from the . . ."1~", ..~;. .., shown in Fig. 5. As stated, top dead center occurs at the position of fuel injector 84 which is at the center of high cam 20 portion 92. There is a period of 30 of dwell as each vane passes over this high cam portion.
Likewise, the fuel injection duration is also 30. The power stroke occurs for each vane as each vane moves from the position of vane 68.10 to the position of vane 68.12, giving a power stroke of 60. Tllere is an exhaust stroke of 60 as each vane moves from the position ofvame68.1,pasttheexhaustport88tothepositionofvane68.3. Thereisthenaperiodof 25 dwell as each vane moves the next 30 over high cam portion 92 between the positions of vanes 68.3 and 68.4 when they are located as shown in Fig. 5. This stroke is shortened, as discussed above, for Miller cycle and K-Miller cycle variations. The intake stroke also occupies 60 of the cycle as the vanes move past primary intake port 86 and secondary intalie port 87 between the positions occupied by vanes 68.4 and 68.6 in Fig. 5. Tllere is then a 30 . 2180198 .

period of dwell as the vanes move over the low cam portion positioned between vanes 68.6 and 68.7 in Fig. 5. The compression stroke occurs in the next 60 of }otation of the rotor bet~veen the positions of vanes 68.7 and 68.9 in Fig. 5.
5 As may be seen in Fig. 5, high cam portions 92 on one side of tne engine are located opposite low cam portions 90 on the other side of ti~e engine such tnat the vanes reciprocate while the distance between the cam surfaces remains relatively constant at the width of each vane.
Engine 14 does not rely upon the cam surfæes to reciprocate the vanes. Instead, as seen in Fig. 1, 5 and 8, tne engine has means for lc~ ,a~ , the vames in~,lldcll~ly of the cam 10 surfaces in tne form of an umdulating cam groove 96 extending about the outer wall 40 of chamber 34. The cam groove 96, also referred to as a guide cam, extends about the stator in an undulating pattern between the cam surfaces 42 and 44 as shown in Fig. 5. In this particular example, tbe groove is generally midway between the cam surfaces although this is not essential.
Each ~ane has a cam follower in the form of a pin 98. The pin 98 of each vane is slightly smaller in diameter than the width of cam groove 96 so tnat the pins slidably follow along tlle groove as the rotor rotates. This may be appreciated from the different positions of the vanes shown in Fig. 5. The pins 98 cause the vanes to reciprocate axially as the rotor rotates.
The provision of a guide cam and follower, in tne form of cam groove 96 and pins 98, means that the force to move the vanes is removed from the carn surfæes 42 and 44. Thus the strength of materials on tne cam surfaces may be reduced so that lighter materials such as aluminum can be employed. In addition, liquid lubrication can be applied to the cam 25 grooves and pins to reduce friction and wear. A lubricant can be introduced into the cam groove, located on housing 18 of the stator, eitner tnrough the rotor and drained out tlle through the outer housing or through the outer housing and drained out through other openings in the outer housing or back through the rotor. The cam groove can be machined directly into the outer housing, as in the illustrated ~mhn~imrnt of Fig. I, or can be mach~ned " ~. 2l8ol98 .

into an insert which is cast or otherwise attached to the inside of the outer housmg. The cam groove may be coated with a wear resistant material if desired.
The pins 98 may be provided with a follower member rotatably located thereon. The S follower member may be generally elliptical with trlmcated ends. The follower member increases the hydrodynamic load carrying capacity of each pin.
Alternatively, separate loose members can be attached to each pin 98. These are loose parts used to guide the lubricant towards the sides of groove 96 to enhance the hydrodynamic load 10 carrying capacity of the pins. The follo~ver member may be pointed.
The illustrated pins 98 are cylindrical. However, other shapes are possible such as a truncated oval or other non-circular cross-sections adopted to optimize load carrying capacity The engine described above is a compression ignition engine. The compression ratio is between 14:1 and 22:1 and designed so the engine operates as a true direct injected diesel engine. Altematively tlle compression ratio could be reduced and spark plugs added for a spark ignition engine.
It will be understood by someone skilled in the art that many of the details provided above are by way of example only and are not intended to limit the scope of the invention which is to be deteimined with reference to the followin~ claims.

Claims (14)

1. An axial vane rotary engine (14) comprising:
a stator (16) with a cylindrical internal chamber (34) defined by an annular outer wall (40) and two side walls (36, 38) of the stator, each said side wall having an annular cam surface (42, 44);
a rotor (54) rotatably mounted within the chamber, the rotor having an annular outer wall (66) and a plurality of angularly spaced-apart, axial slots (64) extending therethrough;
a vane (68) slidably received in each said slot, each said vane having an outer edge (74), an inner edge (106) and side edges (70, 72), the side edges slidably engaging the cam surfaces;
means (42, 44) for alternatively expanding and compressing spaces between adjacent said vanes and the cam surfaces as the rotor rotates, said means including alternating first portions (92) and second portions (90) on the cam surfaces, the second portions bring further from the rotor than the second portions, the first portions of one said cam surface being aligned with the second portions of another said cam surface;
means for intaking air into the spaces as the spaces expand when the vanes approach said one second portion of each said cam surface;
means for exhausting gases from the spaces as the vanes approach one said first portion of each said cam surface; and means for continuously injecting fuel into the chamber during each complete revolution of the rotor, said means for injecting being at a position to inject the fuel between each pair of said vanes as they rotate past the fuel injecting means.

2. An engine as claimed in claim 1, wherein the means for continuously injecting includes a fuel injector on each side wall of the engine.

3. An engine as claimed in claim 1, wherein each said fuel injector is located adjacent another said first cam portion.

4. An engine as claimed in claim 1, wherein the intake means includes a primary intake port and a secondary intake port adjacent the primary port and the exhaust meansincludes an exhaust port.

5. An engine as claimed in claim 4, wherein the spaces between adjacent vanes communicate with the exhaust port and the intake port during 60° of rotation of the rotor.

6. An engine as claimed in claim 5, wherein the engine has compression and power strokes each occurring during 60° of rotation of the rotor.

7. An engine as claimed in claim 6, wherein there are periods of dwell as vanes pass over the first portions and second portions on the cam surfaces.

8. An engine as claimed in claim 7, wherein the first portions and second portions extend through a rotational angle of 30° each on the cam surfaces and are connected by sloping cam portions.

9. An engine as claimed in claim 1, wherein there are twelve said vanes spaced-apart 30° about the rotor.

10. An engine as claimed in claim 1, wherein there are sixteen vanes spaced-apart 22.5°
about the rotor.

11. An engine as claimed in claim 4, wherein the secondary port is located closer to said one second portion then the primary intake port.

12. An engine as claimed in claim 1, wherein the intake means terminates at a rotational position in advance of the one second portion of the cam surface whereby expansion continues after air intake is completed.

13. An engine as claimed in claim 4, wherein the intake means includes means for selectively opening or closing the secondary intake port.

14. An engine as claimed in claim 13, having a turbocharger compressor, the means for selectively opening including a bellows operatively connected to the compressor and a valve in the secondary intake port operatively connected to the bellows.