WO2019150336A1

WO2019150336A1 - Rotary engine

Info

Publication number: WO2019150336A1
Application number: PCT/IB2019/050882
Authority: WO
Inventors: Newton BOWER
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-02-04
Filing date: 2019-02-04
Publication date: 2019-08-08
Anticipated expiration: 2020-08-04

Abstract

A rotary piston internal combustion engine (1) comprising a set of spaced apart chambers (3A, 3B) in fluid connection by means of a passage (7) provided with a one-way valve; each chamber (3A, 3B) including a rotor (9) provided with a circumferential lobe (11) sealed against the inner surface of the chamber (3A, 3B), the first chamber (3A) including an air inlet (14) and the second chamber (3B) including a fuel injector (15A) and exhaust port (16), each chamber (3A, 3B) provided with at least closure member to form in the first chamber (3A) a compression space (13B1) and in the second chamber (3B) a combustion space (13A2), with air drawn into the first chamber (3A) and compressed between the lobe (11) and closure member by the rotation of the rotor (9), compressed air transferred by means of a one way valve to the second chamber (3B), mixed with injected fuel and combusted, to drive the lobe (11) of the second chamber rotor forward and generate useful motion.

Description

P01024PC

ROTARY ENGINE

FIELD OF THE INVENTION

This invention relates to an internal combustion engine, in particular a rotary engine.

BACKGROUND TO THE INVENTION

Internal combustion engines operate on the principle that a combustion chamber is filled with a fuel mixture and ignited to create a rapidly expanding volume of gas, which can drive a mass - typically in the form of a piston. The mass is connected to a shaft which causes the shaft to be rotated, which produces useful motion. With multiple combustion chambers similarly connected to the shaft, and timed to be fired sequentially, a series of ignitions causes the shaft to be rotated continuously, which also allows for each mass (the piston) to be reset, once ignited, for the next round ignition.

A problem with conventional internal combustion engines is that each piston is pushed from the cylinder upon ignition, whilst driving a crank shaft to which it is connected, only for it to have to be slowed down and returned to the starting position. This reciprocal motion wastes a lot of energy, which could be useful.

To overcome this problem rotary engines were developed. These typically include a main chamber within which a shaped lobe rotates. The lobe is shaped with 3 tips and rotates within a chamber to create combustion chambers. The rotary lobe used in this does not have to violently change direction during its rotation, hence allowing for much smoother operation, compactness, simplicity and higher power to weight ratios compared to conventional piston type internal combustion engines.

Rotary engines suffered from problems including unreliable apex sealing, high apex seal wear, pre-detonation, and poor shaft lubrication. Some solutions have been devised to address some of these problems in respect of fuel economy, reliability, and emissions but there is room for further improvement. OBJECTIVE OF THE INVENTION

It is an objective of the invention to provide a rotary engine which at least partly overcomes the abovementioned problems.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the invention there is provided a rotary piston internal combustion engine comprising a set of spaced apart chambers in fluid connection by means of a passage provided with a one-way valve;

each chamber provided with a rotor assembly rotatably secured to a shaft common to both chambers, each rotor assembly having at least one circumferential lobe to form a curved periphery with the lobe configured for its apex to extend to proximate the operatively inner surface of the chamber within which it is located, and with the lobe apex being sealed against the chamber inner surface;

each chamber provided with each chamber being provided with at least one closure member reciprocally located with respect to the chamber’s rotor to be movable between an inner position in which an end of the closure member extends into the chamber and an outer position in which the end of the closure member is substantially aligned with the chamber inner surface;

a first of the chambers including an air inlet associated with and located rotationally ahead of each closure member, and the second of the chambers including an exhaust outlet associated with and located rotationally behind each closure member, in respect of the direction of rotation of the rotor, and a fuel inlet located rotationally ahead of the closure member;

operatively for the engine to draw air into the first chamber between the lobe and a closure member rotationally ahead of it, with rotation of the rotor compressing the air, and aligning a vent passage from the first chamber with the passage to force air into a vacuum between a lobe in the second chamber and a closure member behind it, with fuel injected into the air mixture and the resulting fuel and air mixture combusted to drive the force the second chamber lobe away from the closure member behind it, thereby closing the passage with the first chamber and rotating the lobe forward until it passes the exhaust port to exhaust the combustion gasses from the second chamber and create a vacuum in the second chamber again after passing the exhaust port, and simultaneously driving the rotor of the first chamber to draw fresh air in again, compress it and with alignment of the vent passage of the first passage with the passage to allow compressed air to again be drawn into the vacuum behind the lobe of the second chamber and in front of the closure member behind it.

In accordance with a further aspect of the invention there is provided a rotary piston internal combustion engine comprising a housing defining a set of spaced apart chambers;

each chamber being ring shaped with a diameter greater than its depth and rotatably locating a rotor assembly, each rotor assembly being secured to a drive shaft common between at least two rotor assemblies;

the set of chambers comprising a first chamber being an intake and compression chamber, and a second chamber being a combustion and exhaust chamber, with the two chambers being in fluid communication by means of a passage extending between them, the passage being provided with a one-way valve to allow fluid flow from the first chamber to the second chamber only;

with each rotor assembly comprising a rotor secured between an inner rotor disc and an outer rotor disc, and having a central mass from which at least two lobes extend to form a curved periphery with each lobe configured for its apex to extend to proximate the operatively inner surface of the chamber within which it is located, and with the lobe apex being sealed against the chamber inner surface;

with each lobe of the rotor in the first chamber being angularly offset with respect to a lobe of the rotor in the second chamber with the second chamber rotor leading the first chamber rotor by an amount configured to allow the space ahead of a first chamber rotor lobe to be in fluid communication, through the passage, with the space behind its associated angularly offset adjacent second chamber rotor lobe;

with each chamber being provided with at least one closure member reciprocally located with respect to the chamber’s rotor to be movable between an inner position in which an end of the closure member extends into the chamber and an outer position in which the end of the closure member is substantially aligned with the ring inner surface,

the end of the closure member being complimentary shaped and sized to the periphery of the rotor and being provided with a seal to seal the lobe apex against the chamber inner surface, and the sides of the closure member end being complimentary shaped and sized and being provided with seals to assist in forming a seal against the operatively inner surfaces of the inner rotor disc and outer rotor disc rotor respectively, thereby assisting the closure member end to maintain contact with the rotating rotor periphery through reciprocation between the inner and outer positions and to create a seal between a space forward of the closure member end and a space behind the closure member end; with each inner rotor disc being provided with a rotor vent radially aligned with the passage between the first and second chambers and configured upon rotation of the rotor assembly within the chamber for both rotor vents to substantially simultaneously align with the passage to put the first chamber in fluid communication through the one-way valve with the second chamber;

the first chamber further including an air inlet associated with and located rotationally ahead of each closure member and the second chamber including an exhaust outlet associated with and located rotationally behind each closure member, in respect of the direction of rotation of the rotor;

the second chamber including a fuel inlet located rotationally ahead of each closure member;

operatively for air to be drawn into a space created behind a forward lobe of the first rotor and a rearward closure member rotationally located behind it, with the air inlet located between them;

for rotation of the first rotor to move the operative rearward lobe of the first rotor past the rearward closure member and the air inlet, and to move the forward lobe past a forward closure member to define the space within which the air is located between the forward closure member and the rearward lobe of the first rotor,

for the volume of the space within which the air is located to be reduced by further rotation of the first rotor with the rearward lobe of the first rotor rotating towards the forward closure member and compress the air within the space,

for the first rotor vent to align with the passage and the second rotor vent, allowing the compressed air to be forced through the passage and the one-way valve into a combustion space located between an operative forward lobe of the second rotor and a rearward closure member located rotationally behind it and the passage;

injecting fuel into the combustion space to mix with the air to auto ignite causing the fuel and air mixture to combust and form combustion gasses;

for the combustion to drive the forward lobe of the second rotor forward to rotate the forward lobe past a forward exhaust outlet and rotate the drive shaft, allowing the combustion gasses to be exhausted from the second chamber and to reduce the volume of the space within the combustion gasses are located by rotating the rearward lobe of the second rotor towards the forward closure member of the second rotor located beyond the exhaust outlet, with continued rotation of the second rotor substantially emptying the combustion chamber of combustion gasses by rotating the rearward lobe of the second rotor past the exhaust outlet and creating a new combustion chamber under vacuum between the rearward closure member and the forward lobe of the second rotor. There is further provided for the second chamber to include an optional spark plug located rotationally ahead of each closure member in association with the second chamber’s fuel inlet, and for the fuel that is injected into the combustion space to be ignited by means of the spark plug, instead of or in addition to the auto ignition thereof.

There is further provided for the two lobes to extend in radially opposing directions, and for each rotor to have an outwardly curved periphery, and more preferably for the rotor to be elliptically shaped.

There is further provided for each rotor to be elliptically shaped, alternatively to have a trochoidal peripheral shape, including a curtate trochoidal or epitrochoidal shape, and preferably to have a set of lobes in multiples of two, including two lobes, four lobes or eight lobes, with each set of two lobes extending in radially opposing directions.

These and other features of the invention are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of an internal combustion engine according to the invention is described by way of example only and with reference to the accompanying drawings in which:

Figure 1 is a schematic diagram of a side view a rotary cylinder internal combustion engine according to the invention;

Figure 2 is a part sectional end view onto the engine of Figure 1 ;

Figure 3 is a schematic representation showing several embodiments of rotor designs of the invention;

Figure 4 is another schematic diagram of a side view a rotary cylinder internal combustion engine according to the invention, with components annotated; Figure 5 is as part sectional side of a first step in the sequence of operation of the engine of Figure 4;

Figure 6 is as part sectional side of a next step in the sequence of operation of the engine of Figure 4;

Figure 7 is as part sectional side of a next step in the sequence of operation of the engine of Figure 4; Figure 8 is as part sectional side of a next step in the sequence of operation of the engine of Figure 4;

Figure 9 is as part sectional side of a next step in the sequence of operation of the engine of Figure 4;

Figure 10 is as part sectional side of a next step in the sequence of operation of the engine of Figure 4;

Figure 11 is as part sectional side of the last step in the sequence of operation of the engine of Figure 4, before the step depicted in Figure 5 is performed again; and Figure 12 is as part sectional side of the engine of Figure 4 with some features indicated.

DETAILED DESCRIPTION OF THE INVENTION

The rotary piston internal combustion engine (1) according to the invention comprises a housing (2) defining a set of spaced apart chambers (3A, 3B). Each chamber (3A, 3B) is ring shaped and rotatably locates a rotor assembly (4A, 4B) that is secured to a drive shaft (5). A plurality of these assemblies may be secured adjacent each other to a drive shaft (5), to sequentially drive it for a smooth operation.

Each chamber (3A, 3B) is formed in the shape of a ring (6A, 6B) located within its housing (2A, 2B), the ring (6A, 6B) having a diameter which exceeds its depth. Each chamber (3A, 3B) includes a first chamber (3A) being an intake and compression chamber, and a second chamber (3B) being a combustion and exhaust chamber. The two chambers (3A, 3B) are in fluid communication by means of a passage (7) in the housing (2) between the chambers (3A, 3B), the passage (7) being fitted with a non-return valve (not shown), which allows fluid flow from the first chamber (3A) to the second chamber (3B) only.

Each chamber (3A, 3B) contains a rotor assembly (8) which comprises an elliptically shaped rotor (9) located between an inner rotor disc (10A) and an outer rotor disc (10B). The elliptically shaped rotor runs against the inner surface of the ring (6A, 6B), i.e. at the periphery of its lobes (1 1).

Each chamber (3A, 3B) also includes a set of stationary closure members (12), or gates, which are located substantially at a right angle to the drive shaft (5). The gates (12) in each chamber are located on opposing sides of the chamber (3A, 3B), 180° apart. The gates (12) of the first (3A) and second chambers (3B) are located in the same position, i.e. at the top and at the bottom of the chambers, but slightly offset from each at about 5°. Each gate (12) is movable between an extended position and a retracted position. The gates (12) are configured to bear against the periphery of the rotor (9). Each gate (12) is biased, typically by means of a spring (not shown), towards the extended position in which it maintains contact with the periphery of the rotor (9), effectively riding on the periphery of the rotor (9) and reciprocating between the extended and retracted positions.

Each gate (12) is sealed against the periphery of the rotor (9) with which it is associated, and against the sides of the inner rotor disc (10A) and outer rotor disc (10B) respectively.

In combination with the sealed interface between the rotor lobes (11) and the ring (6A, 6B) inner surface, the gates (12) create two sealed spaces (13A, 13B) between the periphery of the rotor (9) and the chamber’s inner surface. Each of these sealed spaces (13) becomes a sub-chamber with a predetermined volume within the chamber (3A, 3B) wherein it is formed. Each chamber (3A, 3B) thus contains two sub-chambers (13A, 13B) formed on either side of the two lobes (1 1) of its elliptical rotor (9).

As mentioned above, each chamber includes a first chamber (3A) being an intake and compression chamber, and a second chamber (3B) being a combustion and exhaust chamber. The first chamber (3A) has an intake sub-chamber (13A1) and a compression sub-chamber (13B1). The second chamber (3B) has a combustion sub-chamber (13A2) and an exhaust sub chamber (13B2).

The chambers (3) also include an air intake port (14), a fuel injector (15A), a spark plug (15B) and an exhaust port (16), all arranged proximate the top of the chambers (3), proximate it’s Top Dead Centre (“TDC”).

The rotors (9) of the two chambers (3) have an angular offset of about 5°, with the rotor (9B) of the combustion and exhaust chamber (3B) leading the rotor (9A) of the intake and compression chamber (3A) in the direction of rotation. This is substantially the same offset of the gates (12), but in the opposite direction. The offset of rotors (9) and gates (12) allows for the smallest distance between the rotors (9). This lessens the loss of compression ratio, due to the centre plate void being outside what would otherwise be the combustion chamber.

The offset between the rotors (9) allows for enough space for compressed air to flow into the combustion sub-chamber (13A2) from the compression chamber (13B1). The offset creates space for the airflow, and when the passage (7) between the first and second chambers (3A, 3B) opens it leads to open space in combustion chamber (13A2) with a straight path.

In use, the outer rotor discs (10A, 10B) create a seal against the rotor housing and each gate (12) creates a seal against the inner rotor and rotor discs (10A, 10B). These seals allow the combustion of injected fuel and air create a compressive force in front of the rotor and a vacuum behind the rotor (9).

As shown in Figure 5, at the start of an ignition cycle, fresh air is drawn through the intake port (14) into the first chamber (13A1) ahead of the first chamber gate (12) located proximate and behind the intake port (14) - for this ignition cycle that gate (12) may be termed the rearward first chamber gate (12A). The rotor (9) will have a rearward lobe (1 1 B) still behind the rearward gate (12B), and ahead of it the forward lobe (11 A).

At this stage a space (17) is thus defined between the rearward first chamber gate (12B) and the forward lobe (1 1 A). With rotation of the first rotor the rearward lobe (11 B) passes the rearward first chamber gate (12B), and the forward lobe (11 A) passes the forward first chamber gate (12A), which is located 180° from the rearward first chamber gate (12B). This means at the same time the rearward and forward lobes (11 A, 1 1 B) respectively pass the rearward and forward first chamber gates (12A, 12B).

The space (17) into which the fresh air has been drawn is now contained between the rearward lobe (11 B) and the forward first chamber gate (12A). With a small amount of further rotation, the rearward lobe (11 B) passes the air intake port (14) which closes the mentioned space for air intake. The space is thus filled with fresh air and sealed. Air is compressed in front of each lobe (11), driven by the rotor (9).

As shown in Figures 6 and 7 the gate top seal and side seals allow compression of air in front of each lobe and the formation of a vacuum behind it. The first rotor (9A) rotates further which moves the rearward lobe (11 B) towards the forward first chamber gate (12A), which compresses the air therein since the space (17) is sealed. With the rearward lobe (11 B) approaching the forward first chamber gate (12A) the compression reaches a maximum at which point the first rotor vent (7A) aligns with the central passage (7). This happens 180° forward from where the fresh air was drawn into the space (17) in the first chamber (3A). A shown in Figure 8, when the top seal and gate meet, there is a zero event (21) . There is no compression, and no vacuum or combustion is occurring.

The fresh air has thus been drawn into and compressed inside the first chamber (3A) - hence it being called the intake and compression chamber. The compressed air is now located in a very small space in the first chamber 180° forward from where air was drawn into the first chamber (3A).

At the same time, as shown in Figure 9, on the axially opposite side of the assembly (1), the second rotor (9B) has rotated in the second chamber (3B) to a point where its forward lobe (1 1A) has passed the central base passage (7). A very small space (18) is defined between the forward lobe (11 A) of the second rotor (9B) and the rearward gate (12B) behind it. This space (18) had just been exhausted from combustion gasses from a previous ignition cycle and is essentially empty. This space (18) is under vacuum since it has been exhausted and with the forward lobe (11A) of the second rotor (9B) passing the rearward gate (12B) the space (18) is effectively increasing from zero - which places it in a vacuum.

The second rotor vent (7B) now aligns with the central passage (7), at substantially the same time that first rotor vent (7A) aligns with the central passage (7). Due to the high pressure in the first chamber (3A) and the vacuum in the second chamber (3B) the one-way valve (not shown) opens which allows the compressed air to flow from the first chamber (3A) into the second chamber (3B). This is also driven by the rotation of the first rotor (9A) which still decreases the volume of the first chamber (3A) and pushes the compressed fresh air through the central passage (7) into the second chamber (3B).

At substantially this time fuel is injected (15) into the second chamber (3B) to mix with the compressed air that is being drawn into the second chamber (3B) through the central passage (7). The spark plug (15B) is then activated to ignite the fuel and air mixture, which causes combustion and generation of large amount of gas under high pressure. The increased pressure in the second chamber (3B) flows back up the central base passage (7) against the one-way valve (not shown), which causes it to close. Additionally, at the same time, the first and second rotor vents (7A, 7B) have respectively rotated past the central passage (7) which also closes it.

This means the fuel and air mixture in the second chamber (3B) is sealed into the second chamber (3B). At its back the rearward gate (12B) is fixed, and the only available moving part is the forward lobe (11 A) of the second chamber (3B). The rapidly expanding gasses from the combustion thus drives the forward lobe (11 A) forward, producing a power stroke. As shown in Figure 10, the power stroke drives the forward lobe (1 1A) forward beyond the point where it passes the next exhaust port (16), which is located again about 180° forward from where the combustion started. The spent gas is then free to escape through the exhaust port (16).

The moment the forward lobe (11 A) passes the exhaust port (16), as shown in Figure 11 , the pressure inside the second chamber (3B) starts to drop, with the gasses being exhausted (16) from the second chamber (3B). At substantially that time the rearward lobe (11 B) of the second rotor (9B) passes the fixed rearward gate (12), and the forward lobe (11 A) of the second rotor (9B) passes the fixed forward gate (12). The space (19) in the second chamber (3B) is then defined between the forward rotating rearward lobe (1 1 B) of the second rotor (9B) and the fixed forward gate, with an exit through the exhaust port. This means the space in the second chamber (3B) diminishes with continued rotation of the second rotor (9) which forces the remaining spent combustion gas through the exhaust port.

Once the rearward lobe passes the exhaust port, which is still behind the forward gate, only a very small volume remains - and this is again sealed. With rotation of the forward lobe past the forward gate a vacuum is formed within the second chamber (3B) ready to receive the next injection of compressed air from the first chamber (3A), for the next ignition cycle.

In respect of the first chamber (3A), once the first rotor vent (7A) has rotated past the central passage (7) the first chamber (3A) is closed. It now has a small and uncompressed volume that is defined between its forward lobe (1 1A) and the forward first chamber gate (12A), which is now located behind the forward lobe (11 A) due to the further rotation of the first rotor (9A). This space (17) is sealed and increases in volume with further rotation of the first rotor (9A), which creates a vacuum within it.

When the forward lobe (11 A) rotates to the point where it reaches the next air intake it is under vacuum and can draw in fresh air again. This next air intake is located about 180° forward from the air intake that drew air into the first chamber (13A) initially.

These pressure differentials facilitate the intake of air into the air intake sub-chamber (13A1) of the first chamber (13A), (behind the 1^st rotor, considering its anti-clockwise direction of rotation) and exhaustion of combustion gasses from the exhaust sub-chamber (13B2) of the second chamber (13B) (in front of 2^nd rotor, considering its anti-clockwise direction of rotation). This also facilitates compression (in front of 1^st rotor) and combustion (behind the 2^nd rotor) satisfying the 4-stroke cycle. The 1^st rotor handles only Intake (behind) and Compression (in front) while the 2^nd rotor handles combustion (behind) and exhaust (in front).

As mentioned above, between the two rotors (9A, 9B) lies the central base, which includes a passage (7) with a non-return valve. The central base facilitates induction of fresh air from the 1^st rotor via its rotor vent to the 2^nd rotor.

The rotor vent (7A, 7B) is a small hole cut on the inside (meaning against the central base) “inner rotor disc” on both rotors. During rotation of the rotor assembly the rotor vent () lines up with the non-return valve in the central base, the pressure differential created by compression in the 1^st rotor (9A) is greater than the vacuum behind the 2^nd rotor (9B).

These two differentials allow fresh air to flow from in front of the 1^st rotor (9A) to behind the 2^nd rotor (9B). After the 1^st rotor (9A) has reached maximum compression, the 2^nd rotor (9B) has now had fuel injected behind it.

The non-return valve is now closed due to the positive pressure created behind 2^nd rotor (9B). The fuel behind the 2^nd rotor (9B) is ignited, the expansion of gasses resulting from the combustion forces the 2^nd rotor (9B) forward. Since both the 1^st and 2^nd rotors (9A, 9B) are fixed to the driven shaft (5), the 2^nd rotor (9B) is rotated around the shaft (5), which in turn is rotated to generate useful motion.

This motion also forces exhaust gasses (left over from the previous rotation cycle) out through the exhaust valve of the 2^nd sub-chamber. At the same time the 1^st rotor (3A) has started compression in front of it and a relative negative pressure differential behind in order to intake new fresh air.

Since each rotor (9) has two apexes (11) and two gates (12) this means that the engine will produce 4 power strokes per rotation.

The rotary piston internal combustion engine according to the invention provides notable advantages over prior art engines, including prior art rotary piston internal combustion engines. The engine (1) minimises fuel inefficiency and large friction coefficients from reciprocating masses. Instead, the engine’s only reciprocating masses are the gates (12). The gates (12) only move a fraction of the distance that a conventional reciprocating piston would, and they weigh only a fraction of the weight of such a piston, and its associated connecting rod and crankshaft.

In respect of weight, the engine (1) according to the present invention is expected to weigh in the range of 1/5^th to 1/10^th the weight of a conventional piston internal combustion engine, providing significant weight benefits.

The engine (1) would only have 2-4 moving parts compared to 100-150 parts for a conventional 4-cylinder piston internal combustion engine.

The conventional problem of pre-detonation, which is a common issue in piston engines, is not present in the engine (1) according to the present invention. The engine (1) has no possible way of pre-detonation, since fuel in only introduced after TDC.

The compression ratio of the engine (1) may be varied, thus providing it with a variable compression ratio. This allows the engine (1) in effect to become its own supercharger. This may be achieved by taking advantage of the different rotors used in the engine to facilitate intake/compression and power/exhaust. Some rotors may be deactivated to decrease compression or to facilitate higher than atmospheric pressures.

The engine (9) has no valves, which increases efficiency and also decreases pumping loses due to a choking effect on the engine (1), which increases power.

The engine (1) has very small oiling areas within the combustion chamber, typically only at the bottom and sides of the gates (12), and it also employs scavenging effects (trailing gates (20) being oiled by residue on the oiled surfaces). This assists the engine in maintaining very low emissions.

The engine (1) is capable of operating reliably across a wide rpm range. Depending on rotor and gate layout, the engine (1) could operate reliably at anywhere from 30 to 30 000 rpm.

The design of the engine (1) allows it to provide an increase of between 100-300% in torque, depending on the radius of rotor and its application, compared to conventional engines. As shown in Figure 3, it is possible to use variations of rotors with different numbers of lobes, for example:

• Four lobes (22), which produces an 8-stroke cycle, or

• Eight lobes (23), which produces a 16-stroke cycle.

Additionally, to the above, and even though the embodiment described above is that of an internal combustion engine (1), the assembly which forms the engine may also be applied in pumping and compression applications. In respect of this, it can be used as a pump or an air/liquid compressor.

The engine (1) according to the present invention is the only engine that can create a larger exhaust chamber than its intake chamber. This allows the engine (1) to be extremely thermodynamically efficient since it allows more time and volume for the combustion gasses to expand, thus increasing to use of energy contained therein to drive the rotor (and the driven shaft), when compared to the energy usage of a conventional a reciprocating piston internal combustion engine.

Some of the notable advantages of the engine according to the invention over the prior art include:

• Instead of using any type of eccentric or crank shaft, the engine employs pure rotation;

• No reciprocating mass;

• No valve-train, passive oiling;

• Only 1 rpm related moving part;

• 2-stroke for double the power, no oiling in fuel and no oil burning;

• There is a vast improvement in balancing and power delivery;

• The torque produced will be far greater than the torque possibly by other engines;

• No other engine can create a longer power stroke than intake stroke, making the engine much more fuel efficient; and

• Low cost to produce.

By way of summary and comparison, an engine (1) according to the present invention compares as follows with conventional piston and rotary engines: Weight

• Piston - 2000cc engine 150kg

• Rotary - 1300cc engine 90kg

• Invention - 1500cc (2-stroke) 15kg

Power/Torque

• Piston - 2000cc = 160hp/200ft.lb

• Rotary - 1300cc = 180hp/180ft.lb

• Invention - 1200cc = 200hp/280ft.lb

Number of parts (basic parts)

• Piston - 4 cylinders = 120 - 140 parts

• Rotary - 2 rotors = 8 - 12 parts

• Invention - Single rotor = 5 parts

It will be appreciated that the embodiment described above is given by way of example only and is not intended to limit the scope of the invention. Modifications of the embodiment are possible without departing from the essence of the invention.

It is for example possible to install a gate to be radially movable with respect to its chamber. This allows for variation of the shape of the relevant sub-chamber, which may be used to modify performance of the engine.

Also, the connection passage between the 1^st and 2^nd chambers may be angled which will offset the apertures of the passage in the 1^st and 2^nd chambers respectively, achieving the same result as offsetting the rotors by a few degrees.

Claims

1. A rotary piston internal combustion engine comprising a set of spaced apart chambers in fluid connection by means of a passage provided with a one-way valve;

each chamber provided with a rotor assembly rotatably secured to a shaft common to both chambers, with each rotor assembly having at least one circumferential lobe to form a curved periphery with the lobe configured for its apex to extend to proximate the operatively inner surface of the chamber within which it is located, and with the lobe apex being sealed against the chamber inner surface;

2. A rotary piston internal combustion engine comprising a housing defining a set of spaced apart chambers; each chamber being ring shaped with a diameter greater than its depth and rotatably locating a rotor assembly, each rotor assembly being secured to a drive shaft common between at least two rotor assemblies;

with each chamber being provided with at least one closure member reciprocally located with respect to the chamber’s rotor to be movable between an inner position in which an end of the closure member extends into the chamber and an outer position in which the end of the closure member is substantially aligned with the ring inner surface, the end of the closure member being complimentary shaped and sized to the periphery of the rotor and being provided with a seal to seal the lobe apex against the chamber inner surface, and the sides of the closure member end being complimentary shaped and sized and being provided with seals to assist in forming a seal against the operatively inner surfaces of the inner rotor disc and outer rotor disc rotor respectively, thereby assisting the closure member end to maintain contact with the rotating rotor periphery through reciprocation between the inner and outer positions and to create a seal between a space forward of the closure member end and a space behind the closure member end;

with each inner rotor disc being provided with a rotor vent radially aligned with the passage between the first and second chambers and configured upon rotation of the rotor assembly within the chamber for both rotor vents to substantially simultaneously align with the passage to put the first chamber in fluid communication through the one-way valve with the second chamber; the first chamber further including an air inlet associated with and located rotationally ahead of each closure member and the second chamber including an exhaust outlet associated with and located rotationally behind each closure member, in respect of the direction of rotation of the rotor;

for the volume of the space within which the air is located to be reduced by further rotation of the first rotor with the rearward lobe of the first rotor rotating towards the forward closure member and to compress the air within the space,

for the combustion to drive the forward lobe of the second rotor forward to rotate the forward lobe past a forward exhaust outlet and rotate the drive shaft, allowing the combustion gasses to be exhausted from the second chamber and to reduce the volume of the space within the combustion gasses are located by rotating the rearward lobe of the second rotor towards the forward closure member of the second rotor located beyond the exhaust outlet,

with continued rotation of the second rotor substantially emptying the combustion chamber of combustion gasses by rotating the rearward lobe of the second rotor past the exhaust outlet and creating a new combustion chamber under vacuum between the rearward closure member and the forward lobe of the second rotor.

3. A rotary piston internal combustion engine as claimed in claim 1 in which the second chamber includes an optional spark plug located rotationally ahead of each closure member in association with the second chamber’s fuel inlet, and the fuel that is injected into the combustion space is ignited by means of the spark plug, instead of or in addition to the auto ignition thereof.

4. A rotary piston internal combustion engine as claimed in claim 1 or 2 in which the two lobes extend in radially opposing directions, and for each rotor to have an outwardly curved periphery, and more preferably for the rotor to be elliptically shaped.

5. A rotary piston internal combustion engine as claimed in any one of claim 1 to 3 in which each rotor is elliptically shaped.

6. A rotary piston internal combustion engine as claimed in any one of claims 1 to 3 in which each rotor has a trochoidal peripheral shape, including a curtate trochoidal or epitrochoidal shape.

7. A rotary piston internal combustion engine as claimed in claim 5 in which each rotor has a set of lobes in multiples of two, including two lobes, four lobes or eight lobes, with each set of two lobes extending in radially opposing directions.