CA1074702A - Rotary engine - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A radial engine with a rotating cylinder block is disclosed which is capable of high rates of rotation although operating on the two stroke cycle. An intake air compressor and an exhaust driven turbine are provided, both in driving connection with the same output shaft as the cylinder block. A peripheral manifold serves both to provide the stator of the exhaust turbine and to mask exhaust passages from the cylinders in the block so as to modify the two stroke cycle of the engine by effectively advancing the end of the scavenge phase. A system for recovering oil from the block is disclosed, and the block is reinforced by a peripheral tension band.

Description

l0~4~a2 FIELD OF THE INVENTION
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This invention relates to radial internal combustion engines of the type in which a cylinder block rotates rela~ive to a crank-shaft, the latter generally being stationary, and more particularly though not in all aspects to engines of this type employing a two stroke cycleO
REVIEW OF THE PRIOR ART
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Numerous proposals have been made ovex many years for radial engines having cylinder blocks rotating about a stationary crankshaft, the attraction of this arrangement being ~hat although the pistons of the engine execute a reciprocatory motion relative to their cylinders, their absolute motion is a rotation about the ~ -crankpinO Although there is a cyclical variation in rotational velocity of each piston about the crankpin~ any resulting torsional moments will largely or wholly cancel in a multicylinder engine~
with the re ult that the engine is almost perfectly balanced, whilst the block also acts a~ a flywheelO
Although some engine~ of thi~ general type have been succes4-fully utilized in the past, such engine-q have on the whole found little fav~ because of substantiaI problems in con~truction and ::
operationO The rotating cylinder block i9 subjected to centrifugal stre~ses which reach vary high levels at high rotational velocities 9 and there are problems in Qupplying fuel and coolant to the block.
In particular, centrifugal forces also give rise to consi~erable lubrication problem~ due to the difficulty of recovering lubrican~
from tha rapidly ro~ating block~ For this reason, "total-loss"
lubricating ~y~tem~ have generally been u~ed, thus increasing lubricant consumption and exhau~t pollutionO
A number of the proposal~ which have been made for engines with rotating cylinder block~ have been for engines operatiny on 107~7(~Z

the two stroke cycleO The advantages and disadvantages of the two stroke cycle as compared with the four stroke cycle have been discussed at length in the litera~ure of the art and need not be re-cited hereO Reference may be made however to "The High Speed In ~rnal Combustion Engine", Ricardo and Hempson~ 5th Edition, 1968, Chapter 10 for a discussion of these advantages and disadvantagesO
Suffice it to say that it has generally been con~ ered that the two stroke cycle can normally only show advantages over the four stroke cycle in engines operating at no more than relatively moderate speeds.
Proposals have al~o been made to provide engines having rotating cylinder block~ with ~tructure~ surrounding the block which act as valve means to control the inle~ or exhaust of gases from the engine cylinders~ to support turbine blades against which ex- .
haust gases escaping from the cylinders can rsact, to deliver high tension electrical pul~es to spark plugs in the block7 and to per-form various other functionsO Where such ~tructures act a~ manifold~
for inlet or exhaust gases, it is important to prevent the e~cape of 9uch gase3, so ~ome kind of seal i5 necessary betwe~n the mani-fold and the blockO The provi~ion of such ~eals by conventionalmeans present~ grave problems; because of the severe conditions and the large diameters and high relative velocities of the parts to :
be sealedO
SUMMARY OF ~HE rNV MTIQ~
The present invention i~ directed to overcoming the pro~
blem~ outlined above with the object o~ providing an internal com-bu~tion engine of high performance and high efficiency capable of running a~ high speeds. A rotating cylinder block is used in con-junction with a peripheral manifold in a manner which enables a two .. , j : .

-` ~0747~2 stroke cycle to be used in a high speed engi.ne.
In my engine, the cylinder block is rendered ~uitable or high speeds of rotation, by forming it from a light metal alloy, and anclosing it within a prestressed high tensile steel rlm which supports it against peripheral forces even though the structure of the block may need to be weakened by ~he presence o~ passage~ for cooling and other air flow as de-~cribed in more detail belowO
A peripheral stationaxy manifold is provided surrounding the rotating cylinder block, the outer surface rim of the cylinder block :~-and the inner surface o~ the manifold cooperating to define twoperipheral axially spaced annula~ air cushion chambers9 within which air cu3hions are ~et up which not only serve to seal the edges of the gap which necessarily exist between the block and ~he manifold but which also help to support the stationary manifold in correct orientation relative to the rotating cylin~er blockO
As is conventional in two stroke engines, the piston~, which ~ :
reciprocate rad~ially relative to the cylinder block, are used to mask and unmask inlet and exhaust ports in the cylinder wall~, so that during a portion the stroke of each piston extending to either 20 side of its top dead centre position both port~ are ma~ked and ;
during a portion of the ~troke extending to either side of its bot~
tom dead centre po~ition neither port is maskedO However~ the mani- :
fold is -qo configured and oriented relative to the stationary crank-sha~t that during the latter portion of the tlme that each ex~aust port i~ unmasked~ the outer end of a passage leading from the port . : -to the periphery o~ the rotating block adjacent the manifold is masked by the manifold ~tructureO This modif ie9 the operating cycle of the engine in a manner described in more detail below, randering it suitable for high ~peed operation~
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Moreover, the manifold define~ two ~eparate openings, through which the outer end of the passage is placed in communication with the atmosphere, normally through separate exhaust pipes and a con-ventional muffler arrangementO The f irst of these openings to enter coincidence with the exhaust passage as the cylinder block ~ :
rotabes pxeferably contains turbine blades by means of which a re-action is applied to the block ass isting its rotation, suppleménting the effect of further coac~ing blade~ provided in the exhaust pass-age ~ The dimensions of this f irst opening are such that it re-ceives the exhaust gases released by unmasking of sach exhaust port :~
by its associated piston, which should occur prior to the unmasking of the associated inlet port~ The second opening coincides with the exhaust passage whilst both ports are un~asked, and contains no turbine blades, thu~ minimizing resistance to scavenging of the cylinder by air entering the inlet portO Thereafter~ the manifold masks the exhaust passage, preventing further loss of air and pro-ducing an effect si~ilar to advancing substantially the masking of the exhaust port by the pistonO Th~s modifies the operating cycle of the engine in a manner which enhance~ efficiency and greatly facilitates high speed operationO
The nece~sity for total loss types o lubrication is avoided by the incorporation o~ an effective lubricant return systemO
Lubricating oil i~ fed through passages in the cranXshaft to the crankpin journal ~urface~, and oil which escapes from the crankpin bearing i~ thrown outwardly into the interior of the cylinder block, where surplu~ oil not required or lubrication of the cylinder wAlls is captured by the hollow interiors of the pi~tons ~ ~upplemented if neces~ary by oil captuxe rece~ses between the pi3ton~0 The oil accumulating within the pi~ton~ can escape through apertures in the ':

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piston walls, conveniently through hollow wrist pins connectingthe pistons to their connecting rods, these apertures coinciding with passages in the cylinders' walls at the bottom dead centre positions of the pistons. The passages in the cylinders' walls and further passages from the oil capture xecesses allow the surplus oil to run into an annular chamber from which it is withdrawn by ducts extending to the crankshaft and thence to a scavenge pumpO
~ ir i9 preferably aupplied to the engine by means of a com-pressor driven by the engine, preferably a radial flow centrifugal compressor mounted concentrically with the crankshaftO This enables qases to follow a generally radial path through the engine~
the operation of which i~ effectively compound, with two 3tages of compression and two stages of expan~ion all drawing power from or feeding power to a common drive shaftO Thus there i~ first stage compression in the compressor, second ~tage compression by the up-stroke of the pistons, first stage expansion from the downstroke of the piston, ~nd second stage expansion in the exhaust passages leading to the turbine formed by cooperation of the rstating block and the exhaust manifoldO
SHORT DESCRIPTION OF THE DRAWINGS
The invention is described further with reference bD the accompanying drawings showing a preferred embodLment of the in-vention and illustrating its operation, in which:
Figure 1 is a radial cross section through the engine on the line I-I in Figure 2, ::
Figure 2 is an axial cro~s ~ection through the engine on the line }I-II in Figure 19 Figure 3 i9 an end view of the angine as ~een from the le~t hand 9 ide of Figure 2, j.. : :

0~ 7~2 , Figure 4 is a fragmentary section on the line rV~IV in Figure 1, Figure 5 is a fragmentary section on the line V-V in Figur~
3, and Figure 6 illustrates diagramat~ically the compound nature of the engine, and also illustrates how more than one bank of cylinders may be utilized in parallelO
DESCRIPTION OF THE PREFERRED EMBODDMENT
The embodiment of the engine of the invention sho~n in the 10 drawings is described belowO It will be understood that for the . ~' sake of claiity~ engine acce~sories of a conventional nature such as fuel pumps, and electrical ~quipment have been omitted~ .
The rotary engine shown in Figures 1 to 5 con8ists of a singlo bank engine, wherein a number of cylindexs having liners 2 ~.
and pistons 4 are housed in a light alloy cylindex block 8 which fonm~ part of a rotating assembly which al~o does duty as a flywheeiO
The block rotates around a ~tationary ~orged ~teel cranksha~t 6. AR
output shaft 10 is at~a~hed to the block by means of a flange 129 '' ~he output shaft runs in a prelubricated roller bearing aæ~embly 14 which i~ receiv~d in a rear mounting 15 for the engineO It may also serve as an input bearing for a gaarbox or transmi3slon (~ot shown)O
A forward engine mount i9 ~ormed by ~he ~tationary crank~haft 6 ' it~el~, held in a suitable known form of anti-~ibration and self-aligning mounting~ :~
The cylinde~ block is supported on the crankshaft by a front main bearing 16 and a rear main roller bearing 18. The rear main bearing is located between ~houlder3 on ~he inner end o~ t,he output shaft 10 and the inner end o the crankshaft 6 thu~ allowing for expansion and also for assembly.

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The cylinder block 8 is of cas~ aluminum or magnesium alloyOThe cylinder llners 2 are of cast iron and have inlet ports 20 and exhaust ports 22 which communicate with inlet passage~ 24 and ex-haust passages 26 extending through the cylinder blockO In order to permit a sufficiently large exhaust port area whilst providin~
adequate support for the rings of the pistons 4, the exhaust ports and passages in fac~ comprise dual, parallel ports and passages.
Cylinder head combustion chambers 28 are fonmed in a cast alloy head band 30 which is an interference fit on the outside of the block 8. Local presæure to maintain the cylinder head joints in a gas tight condition i~ provided b~r a number of bolts 320 A
high ten~ile steel pressure band 34 is then shrink fitted on the outside of the head band 30 providing an initial compre~sive strass on the cylinder block a~sembly~ allowing engine operation at higher speeds than would otherwise be possible without danger of dis-integration of the block due to centrifugal stresses.
Connecting rods of ~orged ~teel alloy connect the pistons 4 and the crankshaf~- 60 One cylinder (that shown uppexmost in Figuxes 1 and 2) has a master rod 36, the other cylinders each having tw~ :
matched connecting rods 38 with their big ends flanking the master rod on either side a~ seen in Figure 20 ~he master rod has a weight equal to the weight of either o~ the othar two matched pairs of rods~ the complete as~embly being balanced.
The ma~ter rod 36 contain~ a shell type bearing 40, and runs on a journal 42 of the crankpin of the crankshaftO The other rods 38 are fitted on the outQide of a ma~ter rod bearing hou~ing 44, and also have ~hell type bearing~ 460 ~he relative movement between the master and the other connecting rod~ i~ only a few deyrse~
The pi3ton~ 4 are of aluminum alloy and fitt~d with a number - 7 ~ :~

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of piston rings comprising compre3sion rings 48 of the chrome plated type and oil ~craper rings 50 of the unplated typeO Each ring is positioned by a pin to ensure that the ends of the rings do not foul the portsO The piston crown 52 has a number of cooling ins or ribs 54 on its inner ~urface, and the piston skirt has one side machined to provide clearance ~or a gear ring 56 mounted on the crankshaft and re~erred to further ~elowO
The little ends 58 o~ the connecting rods are connected to bosse~ 60 within the piston heads by wrist pins 62 in conventional fashion, the wrist pins being retained by circlips 64 and pro~idsd with an internally threadad bore 66 for extraction purpo~esO As well as conventional bores 68 in ~he little ends and bosses to allow lubricant escaping from the big end and crankshaft bearing~
into the pistons to reach the wrist pin~, bQres 70 are formed in the wrist pins ~o that lubricant aceumulating in the re~ervoir formed within the piston crown may enter the bore 66 in the wsist pin. From the wri~t pins, the oil can pass through passages 72 in ~he cylinder liners 2_into an annular channel 74 formed between :~
the cylinder block and the output shaft flange 120 L.ubricant :
captured by recesse~ 76 between the cylinders also pa~se~ into the channel 74 through pas~ages 780 Lubricant is withdrawn from the channel 74 by a sca~enge 9ection of a lubricant pump 80 through spiral ducts 82 formed in an oîl return disc 84 secured to the cranlcshaftO The du~ts are shaped so as to utilize the angular momentum of the oil in the channel 74 to ass ist in its return to the pump 800 The pump 80 i~
hou~ed in a recess in the end of the crankshaft and h~ a driving connectiQ~L~8~ ith the output ~haft lOo Lubricant from the ~cavenge section of ~he pump leave~ the 8 :

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engine through a pa~sage 88 in the crankshaft to an oil coolar;
filter and reservoir (not shown), whence the lubricant requirements of the engine are drawn by a feed section of the pump 80 through a passage 90 and delivered to the crankpin bearings through a passage 920 The oil circulation via ~he pistons helps to cool the latter, which is an important advantage of the arrangementO The desir-ability of effective piston cooling in internal combustion piston engines has long been known but difficult heretofore to achieveO
Fuel enters the engine through a feed shaft 94 and a ro-tating union in the outer end of the output shaft 10~ The shaft94 i8 3upported by pre-lubricated bearing~ 96 and i5 equipped with a seal secured with a threaded ring 980 A balance plate 100 is located over the output shaft 10 and also forms part of the fuel ~y~tem9 a number of paæsages 101 act-ing as a fuel manifold admitting fuel ~rom the shaft 94 via pas-sage~ 103 in the output shaftO The balance plate further contains a commutator 102~ a 81ip ring 104 and a number of magnets 106 which are all fitted in an annular ceramic in~ulator 108~ The plate is also u~ed to accept drill holes (not shown) for final .~.
balancing of the rotating mass of the engineO
A centrifugal air compre3sor ~asing llO`is atta~hed to the front face of the cylinder block and rotates with it thus avoid mg the nece~ity for a rohary union between the compressor and the ~ ~-cylinder blockO However, except adjacent the hub the compres30r casing is spaced from the cylinder block to avoid un~ecessary heat transfer from the lat~-erO An impeller 112 rotates around the crank-shaft 6 on plain bronze alloy bearings 114 and i9 driven by epl-cyclic gearing comprising a gear 116, a shaft 118, a friction or overrun clutch 120 to relieve or reduce ~hock loadings applied ~ 9 , , - .

to the impeller on changes of engine spe0d, a g~3ar 122J and a gear 124 from the gear ring 56 mounted on the crankshaft 6 adjacent the crank throwO Due to the parts 116 to 122 being mounted in eccen-txic position in the rotating assembly, balance weigh~s (not shown) are installed to restore balanceO
The impeller 112 rotates in a dixection oppos ite to the cylinder block and compressor casing llOo Apart from providing a convenient gear arrangement this serves ~he purpose of reducing the total angular momentum of the enyineO
The impeller 112 i9 pOS itioned within ~he casing 110 by means of shims and secured by an inlet blade r.ing 126 which also serves as a connection point ~or an air intake duct, incorporating a throttle valve7 and an air filter system (not shown~0 The im- ;
peller 112 is cast fxom aluminum alloy and is a single shroud~d radial blade type with inducerO It is mounked on a steel hub 128~
which i~ integra} with the gear 1240 The cylinder block 8 and head bank 30 are heavily finned on their front and rear face~ The fin~
130 are reinforced with a number of radial fin supports 132 which are arranged to induce an axial flow of cooling air through the cylinder block and head band. Some of this air is Lmpelled by the fin ~upport~ 132 to flow radially outwards through pas~ages 133 in in the head band 30 and pressure band 34 into two spaced circum- :
~erential groo~e~ 134 in a manifold 136, for a purpose described further belowO
A number of ducts which form the inlet passages 24 are pro-vided in the flywheel, and connect the outer periphery of the com-pres~or housing 110~ as best seen in Figure 5, to the cylindersO
The ducts are shaped ts: enter the cylinder~ ~rom below the inlet ports 20g as shown in Figure 1, to provide an upward or outward flow , ......... , ~; ~ .,",.,.,.. ,.. ,,.,.. , ", ~ .
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into the cylinders, whereby to obtain a desirable flow and ~:wirl in the latterO
Fuel injectors 142 are secured in the cylinder block 8 so that the injector nozæles 143 enter the inlet ~ucts 24 just upstream of ~he inl~ ports 20~ Fuel is supplied to the injectors ~rorn the manifold passages 101 by a number of pipes 144 and banjo fittings 146 to the base of the injectors 1420 A num~er of ducts forming the exhaust passages 26 are also provided in the cylinder block and head and the band 34 connecting the exhau~t ports 22 to the periphery of the rotating assemblyO
The ducts have a rectangular cross sectionO The portions nearest the exhaus~ port~ form the throats o~ divergen~ nozzles and the remainder the diverging portions of the nozzles so that ~he opening :~ :
at the rim is an elongat~d peripherally ~xtending ~lotO A number j :
of steel turbine blades 150 axe fitted into the slot as a unitO
The impulse typs blades are machined or cast as a single unit 152 retained in the ~lot by a nose 154 and a pin 156 in an arrangement ~:
- allowing for expansion and assemblyO
The stationary exhau~t mani~old 136 is a cast aluminum alloy -~
ring machined to fit ovex the machined outer periphery of the band 34 with the min~lum practicable working clearanceO ~ .
The manifold contain~ two separate gas pa~Qages, naming an ~ .
- exhau~t section 158 and a scavenge section 160, separated by a divider 162o A steel turbine blade unit 164 is ~itt~d in the ex-haust sectionO The blade unit 164 and the maniold are both re-cessed on their inner sur~ace~ to form an annular passage 166 ~or the electrode of a ~park plug 1680 A di~tributor contact 170 extend~
to a connector in an insulative cover 172 ~itted to the outside of the manifold, whence connection may be made to the remainder o~ an .

~7~7~2 ignition system (not shown).
An exhaust pipe (not ~hown) and a scavenge outlet pipe (not shQwn) will normally be connected to the outlets o~ sections 158 and 1600 The manifold is split at 174 to allow for the insertion of a thermal barrier strip and shi~s to adjust the clearance between the rotating assembly and the manifoldO
The annular cavities 134 machined on the inner face of the manifold are connected to the pa~sage 166 and are for the purpose of providing air seals o~ mildly pressurized and rapidly moving :~.
air~ received through the pas~ges 133, in the form of rings on each side of the exhaust and scavenge sectionsto contain the gases;
these seals also act to a degree as an air beariny between the manifold and the band 340 There are no openings in the manifold past the end of the scavenge section and for at lea~t the next 180 ~ :
degrees of the periphery o~ the manifold~ this portion forming a mask 180 which prevents any substantial loss o~ induction air fxom the exhaust pas~ages ~6 during filling of the cylindersO
OPERATION OF THE PRBFERRED EMBODDM~T

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~ The operation of the engine, considexing one cylinder during a cycle commancing at top dead centre (T~DoC~) is as follow~S
a~suming that a previous chargs of mixture ha~ just been ignitedO
The cylinder being considered and its a~sociated piston are in the positio~s shown in the top half of FigureR 1 and 20 The ignited gases in the combu-~tion chamber 28 expand and do w~rk again~t the piston, rotating the flywheel assembly ~ncluding the cylinder block in a coun~erclockwi~e direction a~ ~een in Figure 1 to a cylinder po~ition of 68 degree~O At this point the exhau t pc~rt 22 is unmasked by the pi~ton 4 and ga~es at high pre~sure and tmperature escape through the exhau3t portO They are then expanded .. - . . . .

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through the nozzle formed by the exhaust duct 26 and attain a high velocity. In passing through the turbine rotor blades 150 and stator blades 176 of the blade unit 164 they undergo a change in direction and a change in velocityO This results in a substantial reaction force being developed on the rotating assembly in its direction of rotationO As the ejection of gases is tangential to the rim of the xo~ating assembly) ~urther energy is transferred in the form of thrust and reactionO
The volumes of the Pxhaust and ~cavenge sections 158 and ....
160 are comparatively large. Upon entering the manifold the gases in their expanded state are deflected by the manifold blades to~ards ~.
the exhaust outletO The slightly pressurized high velocity air present at the air gap due to the channels 134 offers a high im- :
pedance path to the expanded exhaust gases which are at comparative-ly low pressure, and therefore the exhaust gases are containe At 100 degrees after T~DoCo the inlet port opens and pressu-. ..
rized air from the compressor housing 100 is admitted to the cylin-der through the pas~age 24 and port 20 as the latter i~ unmasked by the piston 40 The flow is directed in a manner to di~place the ~ -re~idual exhaust gases and drive them out o the exhaust port 220 This process of scavenging is assisted by the centriugal forces pre- . .
sent. The exhaust duct 26 i~ now opposite the scavenge s~ction 160 of the manifold 136. ~he scavenge flow is maintained at a high vel~
ocity as the incoming air expels the residual exhaust ga~es from the cylinderO The rea~on for the separate ~cavenge section is to prevent the scavenge gases "seeing~' any higher presæure gases left over from the exhau~t cycle as w~uld be the case in a common manifold as used in many conventional engine30 ~herefore two ~eparate ax~
hau~t pipes are used, which may be joined together at a dis~ance ,,, , ,. , ,.. ; ~ ~ .. : . ' ' ., ''` `, ., ~7~702 from the engineO
The scavenge process continues to 160 degrees past ToDoC~
where the exhaust mask acting as a secondary valve ~ubstantially blocks the exit from the exhaust duct 260 From this point the pres~ure in the cylinder increases as more air enters than leaks out at the air gap between the manifold 136 and the rotating assemblyO This leakage can be reduced by forming additional air cushion channels in the manifold in this ragionO
At bottom dead centre (180 degrees after ~oDoCo) the piston begins its upward strokeO Fuel is injected into the inlet duct 24 from the injector 142 ~o as to enter the cylinder ju~t previous to ~ .
the inlet port closing at 260 degrees after T oDoC o The piston speed has now increased a~d ~o~e precompression o~ the mixture in the cylinder take~ place to a position of 292 degrees after ToD~C~ where the exhaust port 22 closes as it is masked by the ricing pistonO This is followed by compression and ignition of the gases, thu-c completing the cycleO The remaining two cylinders operate on a sL~ilar cycle, following each other at 120 degree intervalsO Whilst the use of thre~ cylinders in a bank, as shown, i9 believed to be the most practicable arrangament, there i~ of course no reason why different number~ of pistons and cylinders could not be employedO ~ikewise, it should be understood that the timing o~ the opening and closing o~ ~he inlet and exhau~t port~ indicated in the oregoing description is by way of example only, and variation~ in timing in different applications or with different engine dimension~ may be made as neces~ar~ as in con-ventional in ~rnal combu~tion engines~ ~owever, it will be under-~tood that it i~ inherent in the porting arrangement used that the unmasking and masking of the inlet and exhau~t poxts will occur - 14 ;~;

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at points symrnetrical abou~ ~op dead centreO Ths use of the mask 180 incorporated in the exhaust manifold enabiles this design constriction to be overcome by effectively advancing the point at which the exhaust port is clo~ed, thus providing almo t th2 same flexibility in selecting the portions of the cycle during which the inlet and exhaust ports are open a~ i~ availahle in a ~our stroke engine O

Ignition and ~uel injection are preferably under electronic controll use being made of any o~ many known systemsO Ignition timing i~ con~rolled by ~he magnets 106 located in the balance :-plate 1009 these causing a pulse to be generated in a stationary sensor coil 182 as they pass the latterO This pulse is amplif ied and usedg suitably delayed, to trigger an electronic or capacitor discharge ignition systemO The same pulse i~ u~ed to control actUation of the injectors which incorporate electrically operated valves, the necessary control signal~ being transmitted to the ro-tating flywheel as~embly by the conunutator 102, whilst the assemb-ly is grounded 1:hrough the slip ring 1049 via carbon brushes i~ a bru~h holder 1830 The electronic system adjusts the ignition :
20 timing and also the injeetion duration by means of a computation derived in known manner from various engine operating parameters Such as engine spaed~ thrott~e position~ inlet air flow rate, etcO
Fuel is supplied to the engine by an ele~tric fuel pump (not shown) equipped with a pressure relief valve.
An important cons ideration in the manufacture and mainte- -nance of an engine is that it ~hould be easy to as3emble and dis-assemble. Some pa~t paper proposals for radial engines have su~fered from the defect that whatever their theoretical merit~g they are impo~s~ble to manu~acture becau~a their assembly i~ a .

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topological LmpossibilityO The present engine is readily assembl~d and disassembled.
In order to assemble the major components of the engine, the crankshaft 6 complete with the front main bearing 16, in the gear ring 56, the rear main inner bearing 18, and the oil return disc 84 are inserted in the cylinder block from the rear. The con-necting rods are then fitted through the cylinder bores~ and their big ends are secured around the crankpin~ acce~s being available for this purpose through the bore~0 The rods are then positioned to receive the piston~, each complete with its forward circlip 640 Each piston is aligned with its respective connecting rod or rods at the bottom dead centre position, whereupon the wrist pin i~
in~erted through the oil opening 72 in the cylinder wall and an aligned opening in the disc 84, and the rearward circlip 64 is fitted. The output shaft .is then ~itted and secured, the oil pump having previously been meunted in its recess in the end of the crankshaft, the head band 30 and reinfoxcing band 34 are fitted to tha cylinder block~ and the manifold 136 is mounted so at to surround the band 34 by means of mounting ~rackets secured to the rear mounting 15 which also support~ the output shaft lO and ~he bearing 140 The engine which has been described above is a compound engine, both in the sense that tha compression of the inlet gases prior to their ignition takes place in two stages~ and in the senss that energy is recovered from the expanding gases after ignition in two stagesO This is illustrated in Figure 6, where inlet air i9 shown entsring a compressor C, represented by the housing 110 and the impeller 112J whence it pa~ses to a cylinder bank A or B (the engine shown in thi~ Figure is a two bank engine _ 16 - ~;

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7~ 2 rather than the single bank engine described above), where ~he gases are further compressed, energy for both stages of compres~ion being drawn from a shaft SO However, before leaving the cylinder banks, the gases are ignited and expand, giving up energy to the shaft S, before being expanded while passing to a turbine ~, formed by the blades 150 and 1769 whei~e they give up more energy to the shaf tO
In conventional turbo-charging, qoms energy from the ex-haust gases of an inbernal combustion engine is given up to a ~:
turbine, used to drive a compressor feeding air to the engine.
Two stroke engine~ wi~h higher pumping losses at higher sp~eds have benefitted in particular by the use of turbo-chargers in re-ducing the~e pumping losses a Connection of the components (exhaust turbine and air compressor) of a turbo-charger to the crankshaft of its associated engine by gears or otherwise re~ults in a com-pound engine, wi~h the energy recovered from the exhaust gases ~ ;
over and above that required to drive the compre~or heing available at the output shaftO The~e principle3 applied to a rotary engine such as has been de~cribed resultin a very compact multicylinder compound engine of high efficiencyO
The energy from the exhau~t turbine section i5 supplied to the compressor by the rotating aæsembly, so as to permit the ex-cess becDming available at the output shaft of the engineO com-pared to a conventional turbo-charger arrangement, the advantagQs of tha mechanically driven cen~rifugal compressor are retained.
At the ~ame time the a3si~tance of the turbine i~ retainedO
By nature of it~ principle the centrifugal compressor rotor reguires a high ~peed of rotation, se~eral times ~reater than that of the cylinder blockO ~his i~ attained by the geared drive - 17 - ;

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~7~7~2 from the crankshaft that has been de~cribedO In the example shown the ratio of this drive .is 5025 to l, giving a relative speed be-tween Lmpellor and housing of about 32,000 rOpOmO for an engine speed of 6,ooo rOpOmo This ratio can of course be varied to suit individual engine or compressor de3ignsO Althou~h the exhaust turbine in the present case is operated at a lower ~peed than optimum, resulting theoretically in reduced efficiency, some com-pensation is realized by utilization o the exhaust energy Lmmed~ate-ly after the gases leave the cylinder exhau~t port, re~ulting in elimination of the losses usually incurred in long exhaust tracts and bends 9 as in conventional enginesO The turbine is al~o en-abled to operate under pulse conditions re-~ulting in higher pow~rO
A somewhat higher ~tar~ing speed will be required than for conventional engine~ unle~s an auxiliary pressurized air ~upply i~ available to 3upply induction air to ~he engine during start-ing. No starting device i~ shown in the drawings, but starting torque could be applied through the output ~haft in any of a variety ~ :
of kn~wn ways~
It will be apparent to those skilled in the art that the improvement~ of the pre~ent invention are directed at both com- : :
pression ignition engines and spark ignition engines, although the drawings show a spaxk ignition engine~ Similarly, there are ~eatures of the engine such as ~he lubrication sy~tem and th~ cDn~
struction of t~e rotating assembly which could be applied to radial angines operating on different type~ of two ~troke or ~our stroke ~ :
cycleO It will ~lso be apparent that a wide ra~ge of detail variation~ may ~e made in ths structure of the engine described without departing from the scope of the invention a~ def ined in the appended claLm~0 - . ., . . .,, : .. . :. .. ,: . : , : ... . ~

z Throughout the design, provision has been made for the use o~ multiple cylinder banks (see banks A and B in Figure 6)o In-take ducts 188 (see Figure 1) for a second bank of cylinders behind the first may ~e formed and used :~or lightening holes9 in addition to lightening holes 131, in the singla bank engine il- :
lustrated in the drawing~ bas.ically the same casting being used in a multiple bank engine. A longer crankshaft with an addition-al throw would of course be required, a~ well as other detail changes which will readily be apparent to those skilled in the 10 artO
It would also be possible to operate the engine described without the exhau~t manifold assembly, although by doing so many of its advantages would be lost~ and al~ernative structure would be required to distribute ignition impulses to ~hespark plugs and to receive the exhaust gases~

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Claims (13)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A two stroke rotary internal combustion engine comprising a cylinder block assembly defining the walls of radially extending cylinders and cylinder heads closing the radially outward ends of said cylinders, a s tationay crankshaft, pistons reciprocating re-lative to said cylinders, said block assembly being rotatable in a predetermined direction and rotating relative to said crankshaft, connecting rods connecting the pistons to the crankshaft, a stat-ionary exhaust manifold member adjacent the external periphery of the cylinder block assembly, and an output shaft connected to the cylinder block assembly, wherein the cylinder block defines inlet and exhaust passages, the inlet passages extending through the cyl-inder block from air compression means to inlet ports in the cylind-ers, and the exhaust passages extending outwardly through the cyl-inder block in a trailing direction relative to said predetermined direction from exhaust ports in the cylinder, walls to outer open-ings in the external periphery of the cylinder block assembly, the inlet and exhaust ports both being positioned to be masked and un-masked by reciprocatory movement of the pistons in the cylinders so that both ports associated with a particular cylinder are open during the radially innermost portion of the stroke of the associat-ed piston and both ports are closed by the piston during the radial-ly outermost portion of the stroke of the piston, the manifold being formed with at least one exhaust chamber so configured and so oriented relative to the crankshaft that it is aligned with the outer opening of the exhaust passage associated with each successive cylinder during relative rotation of the cylinder block assembly and the manifold only during a first part of the period when the exhaust port associated with the exhaust passage is unmasked by the associated piston, and the outer opening of the exhaust passage is masked by the exhaust manifold for the remainder of the period that the port is unmasked.

2. An engine according to claim 1 wherein the exhaust chamber in the manifold is formed in two portions separated so as to enter sequential alignment with the outer opening of each exhaust passage as the cylinder block rotates relative to the manifold, the mani-fold including turbine blades in the first portion of said passage oriented so as to provide a reaction to gas flow from said pas-sages such as to assist relative rotation of the cylinder block and the manifold.

3. An engine according to claim 1, wherein the air compression means comprises a centrifugal radial flow compressor having an impeller located within a housing attached to the cylinder block assembly, and in communication with said inlet ports, the impeller having a rotational axis common with that of the cylinder block assembly, drive means being provided placing said impeller in driving connection with both said crankshaft and said cylinder block.

4. An engine according to claim 3, wherein the drive means comprises a cycloid gear train having a ratio such as to drive the impeller at a higher speed of rotation than said cylinder block.

5. An engine according to claim 4, wherein said drive means is such as to drive the impeller in a direction opposite to the rotation of said cylinder block.

6. An engine according to claim 1, 2 or 3 wherein turbine blades are provided located in the outer openings of the exhaust passages.

7. An engine according to claim 2, wherein the exhaust port of each cylinder is unmasked by its piston before its inlet port, and the first section of the passage in said exhaust manifold is aligned with the outlet of the associated exhaust passage during the period between the unmasking by the piston of the exhaust port and its unmasking of the inlet port.

8. A compound gas engine having a first compression stage formed by a centrifugal compressor receiving atmospheric air, a second compression stage and first expansion stage formed by a radial multicylinder two stroke piston engine assembly having a rotating cylinder block, a crankshaft, and pistons orbiting the rotational axis of the cylinder block and reciprocating relative to radially extending cylinders, said second compression stage receiving air from said first compression stage and a second expansion stage receiving exhaust gases from said first expansion stage and comprising an impulse turbine, said compressor, said radial engine assembly and said turbine being adjacently mounted on a common rotational axis, all in driving connection with a common output shaft, and so that the outlet of the centrifugal compressor connects with inlet ports to the cylinders of the radial engine assembly and exhaust ports from the cylinders of the radial engine assembly communicate via passages of expanding cross-section with the inlet to the turbine, the relative movement of said pistons and said cylinders being timed, and the locations of said ports in said cylinders being selected so as to permit successive compression, ignition, expansion, exhaust and sca-venging of gas admitted to the cylinders, and the relative dispositions of the compressor, the engine assembly and the turbine being such that the path of gases through the engine extends outwardly from said compressor inlet to said inlet ports, and from said exhaust ports through said expanding pas-sages and said turbine, and said exhaust ports are radially outward of said inlet ports.

9. An engine according to Claim 8, wherein the turbine comprises a manifold assembly defining in circumferential sequence a first gas passage housing a set of turbine stator blades and oriented to receive gases from successive cylinders through said exhaust ports during exhausting of said cylinders, a second gas passage oriented to receive gases from successive cylinders through said exhaust ports during scavenging of said cylinders, and a mask thereafter blocking egress of air from said exhaust ports.

10. An engine according to Claim 9, wherein the second compression stage and first expansion stage comprise a plural-ity of radial cylinder two stroke piston engine assemblies having a common crankshaft.

11. An engine according to Claim 1, 2 or 8, having a lubrication and cooling system comprising feed conduit means for oil forming a lubricant and coolant, said means extending through said crankshaft to bearing surfaces thereof in sliding contact with said connecting rods, coolant collection reser-voirs within crowns of the pistons and facing said crankshaft to receive oil escaping therefrom, passageway means in each said piston and in said cylinder block oriented so as to be in alignment when said piston is at bottom dead centre, an annular chamber in said block in communication with said passageway means therein, duct means extending radially from said crank-shaft into said annular chamber, and a scavenge pump receiving oil from said duct means.

12. An engine according to Claim 1, 2 or 3, having inlet, compression, power and exhaust phases, wherein the cylinder block and the manifold cooperate at their periphery to define at least two axially spaced annular air seal cavities, and means are provided placing said cavities in communication with a source of pressurized air, whereby to provide, between the cylinder block assembly and the manifold, axially spaced air seals enclosing the space between said cavities, said cylinder block and said manifold.

13. An engine according to any of Claims 1 - 3, wherein the exhaust passages in the cylinder block form nozzles of which the cross-section expands towards the outer end of the passage.