GB2169964A

GB2169964A - Rotary positive displacement device

Info

Publication number: GB2169964A
Application number: GB08500851A
Authority: GB
Inventors: Stephen Michael Cox
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-01-12
Filing date: 1985-01-12
Publication date: 1986-07-23
Also published as: GB2169964B; GB8500851D0

Abstract

This device comprises a multilobed rotor 1 mounted on a shaft 2 and rotating within a casing 3. Chambers 5 are formed on the outside of this casing, and pivoted flap devices 6 oscillate within these chambers and those formed between the rotor lobes 4, the shape of the rotating rotor face causing them to do so. The space formed between the flap device, rotor face, and the casings is therefore variable in volume and the device can thus be used as a pump or as an engine when adapted accordingly. When two of these units are connected together on a single shaft 2, one unit can operate as a compressor, supplying air 21 to the inlet port of the other unit which operates as a power unit. Adjustable vent valves fitted in the transfer ducts 10 allow the pressure ratio between the two units to be varied, thus altering the compression pressure, and various fuels can therefore be used. An ignition distributor for use in an I.C. engine version of the device has two twin-lobed rotors mounted adjacent one another on the distributor shaft (Figs 4 to 6, not shown). <IMAGE>

Description

SPECIFICATION Outside compressed, positive displacement, rotary internal combustion engine This invention relates to a rotary positive displacement device, in this case operating as an engine, but utilising its properties as a pump in the attached air compressor unit.

Rotary engines of different design are in general use as power units throughout the world, being used to power motor vehicles, aircraft and other machines. The operating principle of these engines may also be applied to pumps for pumping liquids or gasses. It is also possible for rotary engines to be used as power sources when operating as steam or gas engines.

Most rotary engines are either very simple designs of completely rotary action, seeming to suffer from high fuel consumption without any significantly great power increase over the equivalent reciprocating engine; or, they are quite complicated devices involving numerous moving parts and being of relatively high weight, whilst giving only similar power output to their equivalently sized reciprocating counterpart. Also, whereas they have the advantage of operating more smoothly than reciprocating engines, and generally at higher revolutions per minute, they seem to suffer from poor chamber sealing and rapid wear compared to the reciprocating engine. Internal combustion engines generally are not very flexible in the types of fuel which can be used in them, the choice usually being petrol of various grades, or some sort of gas, such as Liquid Petroleum Gas.Once an engine has been designed and built to use a particular fuel, it is usually very difficult and expensive to alter the engine to operate on a different fuel.

According to the present invention, there is a compressor unit and a power unit mounted on a single drive shaft. Air, compressed in the compressor, is fed via a duct to the inlet ports of the power unit. An adjustable valve in the ducts allow air to be vented when the internal air pressure rises above the preset value, thus the pressure ratio between the compressor and power units, and therefore the compression pressure of the engine, is effectivly adjustable. This will allow a variety of different fuels to be used in the engine by the simple expedient of adjusting a valve to a setting suitable for any particular fuel, and, perhaps, changing the fuel injectors.A relatively high power to weight ratio is possible with the present invention, and in addition, fuel burn energy is better utilised than in most engines because the power stroke length is not limited by the fact that induction, compression, power and exhaust are all performed in the same cylinder, as they are in the four stroke reciprocating engine. With outside compression, and the design of this invention, only ignition, power and exhaust functions take place during the power stroke, and there are six power strokes per revolution of the single drive shaft. This is achieved by the use of a rotor incorporating three equally spaced lobes around its circumference, with three depressions forming chambers situated between the lobes.There are also two pivoted flaps, situated within two diametrically opposed combustion chambers on the outside of the rotor circumference, these chambers forming part of the rotor casing. The flaps oscillate between the inside of the combustion chambers and the chambers formed between the lobes of the rotor, being forced to descend by igniting the charge which enters the combustion chamber shortly before the flap reaches top dead centre. As the flap descends into the rotor chamber, it pushes on the rear, downward sloping face of the rotor thus imparting its energy to the rotor. As it enters the rotor chamber, the combustion gasses are allowed into the chamber, and they too impart their energy directly to the rotor face, thus the rotor is turned.An open exhaust port in the rotor casing wall allows the exhaust gasses to escape as the rotor chamber passes it, and the flap is returned to top dead centre by the upward sloping front face of the rotor lobe as it passes beneath it. The compressor unit is constructed in a similar way to the power unit, but the rotor turns in the reverse sense, being driven by the power unit, the flaps thus forcing ingested air to be compressed up into compression chambers instead of combustion chambers. Every moving part operates on the rotary principle, except for the flaps which oscillate.

If the compressor unit design is used on its own, with and the drive shaft is turned by some form of engine or motor, then it will operate as a pump for liquids or gasses.

Also, if the power unit design is used on its own, fuel system and ignition system removed, and steam or gas under pressure is introduced via the inlet ports, then this unit becomes a steam or gas engine of a rotary type. The invention, whilst operating as a rotary internal combustion engine, is also suitable for superchargeing or turbochargeing, and will, if the ignition system is negated, operate on the Diesel principle. Larger units, or several units linked together, would be suitable for powering ships, railway locomotives, generating plant and for similar heavy applications. The invention uses relatively few moving parts compared with similarly sized reciprocating engines. Construction is modular in concept, as in gas turbines, for easier repair and maintenance.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a cross section of the engine, viewed from the left hand side, and showing the flow of air and combustion gasses.

Figure 2 shows a cross section of the power unit module of the engine, viewed from the rear. It also best illustrates the operation of the rotor and flaps.

Figure 3 shows, in diagrammatic form, the layout of the accessory shaft and the units it drives.

Figure 4 shows a top view of the ignition distributor.

Figure 5 shows a rear view of the ignition distributor.

Figure 6 shows a threequarter view, diagram, of the ignition distributor.

Figure 7 shows a top view, diagram, of the fuel injection pump and distributor unit, along with the throttle control valves and fuel injectors.

Figure 8 shows a top view, diagram, of the fuel distributor.

Figure 9 shows a side view, diagram, of the fuel distributor.

There arse seven sheets of drawings and diagrams. Sheet 3 shows, diagramatically, the operation of the compressor unit of the engine, and sheet 4 shows the operation of the power unit of the engine, in diagramatic form.

Referring to the drawings, the engine is comprised of two modules, a rotary compressor and a rotary power unit, both mounted on a common drive shaft, and both being of similar design.

The compressor consists of a three lobed rotor (1) mounted on a drive shaft (2) and enclosed within a casing (3), the rotor being made to rotate by the power unit which is mounted on the front end of the same shaft (2). As the rotor rotates, air is drawn into the expanding chamber (4) formed between the rotor lobes, and carried towards the compression chamber (5). An "aerofoil" shaped flap (6) is mounted on a pivot shaft (7) which allows it to oscillate up and down within the compression chamber (5), this flap being cooled by air circulating around the hollow interior of the flap body, its entry and exit being via the hollow centre of the pivot shaft. A roller seal (8) is fitted to the thin end of the flap. As the rotor lobe passes beneath the flap, the flap begins to descend out of the compression chamber (5) and into the rotor chamber (4) which is full of air.The rotor revolves further, and the flap, having passed bottom dead centre, is forced to rise up into the compression chamber (5) by the slope of the rotor face, compressing the air above it into the compression chamber (5). This compressed air then passes through a non-return valve (9) and into the transfer duct (10) which transfers it, still under pressure, to the inlet port of the power unit (11). After the rotor lobe has passed beneath the flap, the process is repeated. There are two flaps and two compression chambers in the compressor unit, and thisallows six compression strokes per revolution of the drive shaft (2). The open, valveless, air intakes (12) are on the inner face of the rotor casing, and all air, intake and cooling, is drawn through a large centrally located air filter (13).The rotors are air cooled by circulating air around the hollow interior of the rotor, assisted by an axial fan (14) mounted in the rotor hub, this air being extracted through the hollow centre of the drive shaft (2) by a centrifugal fan (15) mounted on the front of the drive shaft behind the toothed belt drive pulley (16). The two compression chambers are diametrically opposite each other on the outside of the rotor casing, and they have detachable heads for ease of maintenance. The casing is drilled to form a gallery to carry water for compressor cooling. The compressor rotor rotates in the opposite sense to the power unit rotor, although mounted on the same shaft, and this is achieved by fitting the rotor casing the opposite way to that of the power unit casing.Face plates remain in the same relative positions, this being possible as the casing is tubular, the plates being bolted to either end, with gaskets between the three parts. A piston ring type seal is clipped to each side of the flap(6), the upper edge of this seal (65) is tapered to promote entry of the flap into the chamber (5). The rotor also has similar seals fitted to it (64).

The power unit consists of a three lobed rotor (17) [mounted on a drive shaft (2), and enclosed within a casing (18)1, which is made to rotate by the action of an air cooled flap (19) of basically "aerofoil" shape which is mounted on a pivot shaft (20). Compressed air (21) from the compressor unit is fed into the combustion chamber (22) via a transfer duct (10). There are two combustion chambers, diametrically opposed and positioned on the circumference of the rotor casing (18), these being detachable for servicing. As the rotor turns, its shape causes the flap (19) to rise into the combustion chamber (2 2), the valve (23) closes the inlet port (11), forced to do so by the flap, and as the flap continues to rise to top dead centre, the air is further compressed into the combustion chamber.

During this secondary compression, fuel is injected, in the right proportions, by the fuel injector (24), and when maximum compression is reached, the mixture is ignited by the sparking plugs (25) and the resultant heating causes the mixture to expand rapidly within the combustion chamber. At this point of maximum pressure, the lobe of the rotating rotor moves from under the flap, allowing the flap to be pushed down by the hot mixture, the flap roller seal(26) running down the sloping rear face of the rotor and thus causing the rotor to turn.

In addition, as the flap moves down and out of the combustion chamber (22) and into the rotor chamber (27), the hot, high pressure gasses are allowed into the chamber formed between the rotor lobes (27) and a pressure is applied by the gas directly to the rotor face, causing the rotor to turn further.

When the flap (19) has reached bottom dead centre, the gas pressure is greatly reduced due to expansion of the gas, and the flap is again forced up into the combustion chamber by the action of the rotor as its next lobe passes beneath the flap.

As the flap rises up, the chamber containing the hot exhaust gasses (27) begins to pass the open, valveless, exhaust port (28) in the casing wall, and the gasses escape into the exhaust pipe (29). There are two exhaust pipes, one for each combustion chamber, and there are four sparking plugs, two per combustion chamber. The underside of the flaps assist the exhaust gasses to leave the chambers. This process is repeated three times per combustion chamber per revolution of the drive shaft, making six power strokes per revolution in total.

Some inlet air enters the combustion chamber before the flap has sealed it completely, thus purging the combustion chamber. The rotor is air cooled by circulating the cooling air around the hollow interior of the rotor body, an axial fan (30) mounted in the rotor hub draws in cooling air through the central air filter (13), this air being ex tracted through the hollow centre of the drive shaft (2) by a centrifugal fan (15) mounted on the front of the drive shaft, behind the toothed belt drive pulley (16). A balance pipe connects the two transfer ducts to stabilise any pulsing of the compressed air from the compressor and to equalise the pressure, and an adjustable vent valve (31) is mounted in this pipe to allow the pressure ratio between the compressor and the power unit to be varied, which effectively makes the compression pressure in the power unit variable.The engine can run therefore using fuels of different qualities, without major modifications to the engine being undertaken to enable it to do this. The engine casing is drilled to form a gallery to carry cooling water, the cooling water system using a standard radiator and thermostatically controlled electric fan.

An accessory shaft is mounted on the upper left hand side of the engine (when viewed from the front), and this shaft (32) is driven by a toothed belt (63) from the main drive pulley (16) on the front of the drive shaft (2). This shaft (32) carries the rotary cooling water pump (33), the ignition distributor (34), the rotary oil pump (35), and the combined rotary fuel pump and fuel injection distributor unit (54). The shaft runs in two bearings (37), these being housed in removable housings (38), one on each of the engine unit casings, and the shaft runs at half the speed of the main drive shaft (2).

The ignition distributor is designed to run at half engine speed and provide six ignition sparks per revolution of the drive shaft (2), three for each combustion chamber, utilising a high powered coil and electronic breakerless ignition system. A two tier rotor arm (39) rotates in a distributor cap (40) which has two rings, one above the other, connecting three "contacts" spaced at intervals of one hundred and twenty degrees, in each ring Two sparking plug leads emmanate from each ring, these leading respectively to the two spark plugs in each combustion chamber head. The rotor arms (39) are double ended and fixed at ninety degrees to each other, one above the other, so that contact can be made at either end of the two cross arms.

The lower ring of contacts in the distributor cap is displaced by sixty degrees from the upper ring, this provides the required three ignition sparks per combustion chamber per revolution of the drive shaft (2). There is a flat, non-conductive shield (41) fitted below, between and above the two layers of the rotor arm. This shield (41) is to prevent unwanted arcing within the unit. The rotor arm is constructed in two halves, split along the axis to form two "offset V" shapes, which clip together around the accessory drive shaft (32) which runs through the axis of the distributor unit, the body being a slide fit during assembly, then being secured to the power unit casing.The contact which supplies the electricity to the unit is a ring contact on the foreward (upper) end of the rotor arm, electricity being fed to this ring (42) by a brush mounted in the distributor body, the lead from the coil being secured to this brush (43). Advance and retard of the ignition timing is by mechanical linkage which rotates the body of the distributor a small ammount, thus offsetting the spark timing.

The fuel pump and combined distributor unit for the fuel injection system is designed to provide six fuel injector cycles (three for each injector)per rev oiution of the drive shaft (2), whilst running at half engine speed. The pump is a gear type rotary unit, the accessory shaft (32) running through the centre of the inner gear wheel (44). The pump unit is a slide fit onto splines cut on the rear end of the shaft (32), a system of pegs being used to secure the fuel distributor section in the correct position for injection timing. Fuel is drawn into the expanding chamber of the pump by an opening on the side of the pump body (54), this opening (46) having the fuel pipe from the primary fuel pump (an electrically driven unit mounted on or near the fuel tank) feeding into it.A fine fuel filter is positioned in the fuel line between the primary pump and the inlet port of the injection pump. An outlet port, on the distributor side of the injection pump, is situated in the pump body at the point where the pump chamber is at its smallest, the fuel being forced through this port (47) in the interior of the combined unit. The fuel then travels through a tube drilled in the unit body to another port (48) which allows it to enter the fuel duct (49) drilled through the axis of the fuel distributor drive shaft (50), via a series of tubes which are drilled across the drive shaft at this point. The end of the drive shaft (50) locates directly into the rear end of the accessory drive shaft (32), its locating pegs being so designed that it will only fit one way, so that fuel injection timing is correct for engine operation.

The fuel is then forced to travel along the fuel duct (49) to a two tier system of delivery tubes drilled diametrically across the short, cylindrical fuel delivery head (51). Three tubes are drilled on one plane at sixty degrees to each other, crossing in a chamber at the shaft (50) axis. Three more tubes are similarly drilled on another plane, parallel with the first, further along the delivery head (51), but these tubes are displaced by thirty degrees from the first layer in azimuth, the chamber formed at their intersection being linked to the first chamber. This arrangement gives six outlets per layer, these outlets feeding the fuel into one outlet port (52) per layer, a pipe from each outlet port leading to a fuel injector, one in each respective combustion chamber head. A seal (53) between the two layers of delivery tubes, ensures that fuel does not crossfeed within the distributor body (54). A fuel metering (throttle) control valve (55) is located in each of the two pipes supplying the fuel injectors, these valves being connected by a linkage to an engine speed control device (throttle), with unrequired fuel being returned to the fuel tank via a bleed-off pipe. Various seals are used within the fuel pump and distributor unit to stop fuel leakage. The control valves (55) are connected to the compressed air supply control valve (31), so that fuel may be shut off when the throttle is closed, thus slowing the rotation of the engine with minimum fuel wasteage.

The pulse effect that the action of the delivery head has on the fuel in the injector feed pipes, causes pressure differences at the injectors, a high pressure pulse causing the injector to release its fuel (an amount measured by a combination of the volume of the delivery tube in the delivery head, pump pressure, and the setting of the fuel metering control valves) into the combustion chamber (22). An additional controlable valve (56) allows fuel pressure to be varied between the pump and the fuel delivery head, this valve being situated in the fuel transfer tube (48) which runs between ports (47) and (49). A bleed-off pipe returns unwanted fuel to the fuel tank from this valve. The mixture strength is adjusted by altering the relationship between the fuel metering control valves (55), and their colocated or linked compressed air supply control valve (31).The fuel pump and distributor unit body (54) is secured to the casing of the engine compressor unit.

Lubrication of the ball and roller bearings within the engine is by a "dry sump" system, utilising an oil filter and an oil cooler radiator. The oil pump is a twin chamber unit (35), being a slide fit onto splines cut in the accessory shaft (32) during assembly, the driven gears of the pump fitting onto these splines. One pump chamber supplies oil to the bearings, and the other supplies oil on an intermittent spray basis to the rubbing surfaces within the engine, namely the rotor and flap seals, inner casing walls and inlet valves. Oil is stored in a separate tank which is divide into two oil storage compartments, and which can be mounted away from the engine, being connected to it by two oil supply pipes to the pump.

Starting is achieved by the operation of an electrically driven starter motor (62) which is permanently engaged via a toothed cog with the toothed drive belt (63) on the front of the engine. This unit also operates as an alternator, its function controlled by a switch, once the engine is running, and thus supplies electrical power. It is mounted on the casing of the power unit, on the upper right hand side of the engine (when viewed from the front).

The rotary cooling water pump (33) is of the concentric gear type, and the unit is a side fit onto splines, cut in the accessory drive shaft (32) during assembly, the inner gear being the driven gear, and the drive shaft passing through this. The pump supplies cooling water circulation through water galleries in the engine casings, the two units being connected by two pipes (57), the water being cooled by a standard radiator in a closed system.

This radiator can be mounted away from the engine, being connected to it by hoses. A thermostatically controlled electric fan draws cooling air through the radiator. Power is taken from the engine via a standard flywheel (58) and ciutch arrangement at the rear of the compressor casing, being fixed directly to the drive shaft (2). A propeller shaft or torque converter or other device can also be driven from this power take off point.

A mesh guard (59), hinged to the two cooling water pipes which connect the two sections of the engine, and to a third metal pipe (61) running between the casings below the central drive shaft casing (60), is made in three sections and encloses the centrally located intake air filter (13). This filter is circular in shape but split vertically into two halves for ease of fitting and removal during routine serviceing. The lower metal pipe (61) serves as the oil sump drain, oil from this sump being fed back to the oil storage tank. The water pipes (57) and the oil sump drain (61), along with the drive shaft casing (60), provide the means of securing the compressor casing and power unit casing to each other in a rigid fashion.

Different systems of fuel injection, ignition, lubrication, starting, cooling and engine speed and power control can be used, a computerised engine control system being particularly suitable. The engine can also work on the Diesel principle, the ignition system not being required in this case. Also, carburetters can be used in the transfer ducts in place of the fuel injection system, and use of a two stroke petrol/oil mixture would provide lubrication of the rotor and flap seals if used in place of the intermittent spray system. If required, the engine could also be supercharged or turbocharged. Any compressed air bled from the compressor can be stored in a separate tank and used for various functions such as starting, cooling certain parts, operation of the vehicle brakes, or even operation of vehicle windows, along with many other possible uses.The engine may operate without any flap devices in the power unit, the rotor face being reprofiled in this case.

Note: There are additional parts listed in the key which, for clarity, are not shown on the drawings.

KEY to diagrams and drawings: 1 Compressor rotor 2=Main drive shaft 3=Compressor casing 4=Chambers between compressor rotor lobes 5=Compressor chamber 6=Compressor flap device 7=Compressor flap pivot shaft 8=Compressor flap roller seal 9= Non return valve in transfer duct 10=Compressed air transfer duct 11=Power unit inlet port 12=Air intakes 13=Air filter 14=Axial fan in compressor rotor hub 15=Centrifugal extractor fan 16=Toothed belt drive pulley 17=Power unit rotor 18=Power unit casing 19=Power unit flap device 20=Power unit flap pivot shaft 21=Compressed air 22=Combustion chamber 23= Power unit inlet valve 24=Fuel injectors 25=Sparking plugs 26=Power unit flap roller seal 27=Chambers between power unit rotor lobes 28=Exhaust ports 29=Exhaust pipes 30=Axial fan in power unit rotor hub 31 =Adjustable air vent valve 32=Accessory drive shaft 33=Cooling water pump 34=lgnition distributor 35=Oil pump 36=Main rotor bearings 37=Accessory shaft bearings 38=Accessory shaft bearing housings 39=lgnition rotor arm 40=lgnition distributor cap 41=lgnition arcing shield 42=lgnition ring contact 43=Brush 44=Fuel pump inner gear wheel 45=Flap pivot shaft bearings 46=Fuel inlet port 47=Fuel outlet port(pump) 48=Fuel duct inlet port 49=Fuel duct 50=Fuel distributor drive shaft 51=Fuel delivery head 52=Fuel distributor outlet ports 53=Fuel delivery head seals 54=Fuel pump and fuel distributor body(combined unit) 55=Throttle control valves 56=Fuel pressure control valve 57=Cooling water connecting pipes 58=Flywheel 59=Air filter mesh guard 60=Main drive shaft casing 61=Oil sump drain 62=Combined starter/alternator unit 63=Toothed drive belt 64=Rotor edge seal 65=Flap edge seal 66=Cooling water channels 67=Flap cooling air duct 68=Accessory shaft drive pulley 69=Engine bearers 70=Transfer duct balance pipe

Claims

1. A rotary positive displacement device comprising a rotor with one or more lobes, enclosed within a casing, and one or more pivoted flap devices which oscillate between enclosed chambers situated on the outside of the rotor casing and the chambers formed between the rotor lobes, which acts either as a pump or as an engine.

2. A rotary positive displacement device, consisting of two units as claimed in Claim 1, both being mounted together in such a way that one acts as a compressor and the other acts as a power unit, and when so linked, forming an engine.

3. A rotary positive displacement device, as claimed in claims 1 and 2, when two or more similar units are linked together to form a compound engine or multiple unit operating as an engine.

3. A rotary positive displacement device as claimed in Claim 1 or Claim 2, comprising a three lobed rotor enclosed within a casing, with two flap devices mounted on pivot shafts and which oscillate between two enclosed chambers situated on the outside of the rotor casing and the chambers formed between the rotor lobes, and being so arranged as to provide a total of six flap device operating cycles per revolution of the rotor, which acts either as a pump or as an engine.

4. A rotary positive displacement device as claimed in Claim 3, consisting of two such units linked together in such a way that one unit operates as a compressor which supplies compressed air to the other unit, which acts as a power unit, thus forming an engine which provides up to six power strokes per revolution of the power unit rotor.

5. A rotary positive displacement device as claimed in any preceding claim which, when operating as an engine, is made to operate with either fuel injection or carburetter(s) and with or without the use of an ignition system, or being made to operate with either mechanical or electronic control devices.

6. A rotary positive displacement device as claimed in any preceding claim which, when operating as an engine, is fitted with a valve system which allows the inlet air pressure at the power unit air inlet port to be varied or predetermined so as to have the effect of varying the compression pressure within the power unit, thus making the engine suitable for the use of a variety of fuels.

7. A rotary positive displacement device as claimed in Claim 1 or Claim 2 when made to operate as a gas or steam engine, and also when operating thus being linked in any fashion to another engine to form a compound engine, or an engine/ pump combination which utilises a unit as claimed in these claims.

8. A rotary positive displacement device as claimed in any preceding claim which has one or more pivoted flap devices housed within one or more compression chambers and used as a compressor to supply air to other pivoted flap devices housed in diametrically opposed or adjacent combustion chambers, the pivots of these flaps being arranged in the casing around the outer edge of one multilobed rotor, and which operates as an engine.

9. A rotary positive displacement device as claimed in any preceding claim being constructed from any metal, plastic or ceramic materials or any combination or composite of these materials.

10. A rotary positive displacement device as claimed in any preceding claim being made to operate as an engine designed to run on any fossil fuels or synthetic fuels, be they liquid, solid, gaseous or plastic in nature, and regardless of whether or not they are derived from waste products.

11. A rotary positive displacement device as claimed in any preceding claim when the flag device pivot axes are either parallel to or not parallel to the rotor axis, and with the rotor face either parallel to or not parallel to its axis, and with or without any gas flow control devices.

12. A rotary positive displacement device, as claimed in any previous claim, when operating as a power unit or engine, without the use of any oscillating flap devices, but with specially shaped combustion chambers and with a specially shaped rotor circumference where the action of the rotor in relation to ports in the rotor casing controls the flow of inlet air and combustion gasses, with or without the use of valves of any kind.

Amendments to the claims have been filed, and have the following effect: (a) Claims 1 to 12 above have been deleted or textually amended.

(b) New or textually amended claims have been filed as follows:

1. A rotary positive displacement device comprised of a rotor with three lobes, enclosed within a casing, and two pivoted flap devices which oscillate between enclosed chambers situated on the outside of the rotor casing and the chambers formed between the rotor lobes; when there are two such devices mounted on a common centrally located drive shaft, one device being suitably equipped to form a power unit and the other, operating in the reverse sense, forming a compressor driven directly by the power unit and which supplies compressed air to this power unit, and thus forming an engine which provides six combustion cycles per revolution of the drive shaft; an adjustable compressed air vent valve being incorporated between the two units, allows the inlet air pressure at the power unit air inlet port to be varied or predetermined, so as to have the effect of varying the compression pressure within the power unit, thus making the engine suitable for the use of a variety of fuels with little modification to it.

2. A rotary positive displacement device, operating on the same principles and being similarly constructed to that as claimed in Claim 1, but where a multi-lobed rotor is enclosed within a casing, and several pivoted flap devices oscillate between enclosed chambers situated on the outside of the rotor casing and the chambers formed between the rotor lobes, where there are some of the flap devices operating as in the power unit and some, operating in the reverse sense, performing as in the compressor unit to supply compressed air to the power flap devices, all such devices being arranged around the circumference of the single multi-lobed rotor, variable or adjustable valves being situated in the compressed air ports which link the two complimentary flap device houseing chambers, so as to provide for a variable or predetermined inlet air pressure which effectively varies the compression pressure in the combustion chambers, thus making an engine suitable for the use of a variety of fuels with little modification to it.