GB2212216A

GB2212216A - A rotary combustion engine

Info

Publication number: GB2212216A
Application number: GB8726220A
Authority: GB
Inventors: Donald Kirk Anderson; Kim Stephenson
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-11-09
Filing date: 1987-11-09
Publication date: 1989-07-19
Also published as: GB8726220D0

Abstract

The engine comprises a housing 4 defining an elliptically shaped enclosure 15 containing a substantially circular rotor 2 which divides the enclosure into a primary compression chamber 30, 31 and a combustion chamber 29, 32. At least one radially biased vane 20, 21, 22 is mounted in the rotor to sweep each chamber as the rotor rotates. Air and gas are admitted to the primary compression chamber through inlet 14 and exhaust gases are vented from the combustion chamber through exhaust 13 to drive a turbo-charger 1. Compressor means 3 is connected between the primary compression chamber 30,31 and the combustion chamber 29, 32, whereby air from the primary compression chamber 30, 31 is compressed and released into the combustion chamber 29, 32. The compressor means may comprise a rotary compressor 37 and an associated rotary valve 40, or a separate compression space (44, Fig 3) having a respective cam operated valve (45, 46) at its inlet and outlet ends. <IMAGE>

Description

A R0TAniY C0I'BUSTI0I-7 ENGINE The present invention relates to an improved rotary combustion engine.

Rotary combustion engines have been known for many years. Indeed, some embodiments such as the Wankel engine have received sustained development efforts in many countries. Nevertheless, an efficient, simple, economical, durable, flexible and reliable rotary combustion engine has yet to become developed. As a consequence, the full potential of rotary combustion engines has yet to be fully exploited on a commercial basis.

Conventional rotary combustion engines are known comprising complex arrangments of vanes and vents carried in the engine housing to define compression and combustion chambers. In many respects, these cole systems are over designed and do not enhance the efficiency of the engine. Certainly, rotary combustion engines comprising these known arrangements of vanes and vents are not economical to produce.

St is an object of the present invention to provide a rotary combustion engine which is capable of meeting the requirements identified above, fro both 2. technical and a commercial point of view.

According to the present invention there is provided a rotary combustion engine comprising a housing defining an eliptically shaped enclosure, a substantially circular rotor rotatably housed within the enclosure and dividing the enclosure into a primary compression charnber and a combustion cha~,lber, at least one radially biased vane mounted in the perimeter of the rotor and adapted in use to sweep each chamber as the rotor rotates within the housing, an inlet to sad primary eompressio carnies for air and fuel, an outlet from said combustion chambers for venting exhaust gases and a compressor wherein air introduced into the primary compression chamber is compressed during a compression part of the engine operating cycle and released into the combustion chamber during a combustion part of the engine operating cycle.

Preferably, a plurality of radially biased vanes are provided which are equilangularly spaced around the perimeter of the rotor. Conveniently, three equilangularly spaced radially biased vanes are provided.

Preferably, each vane is housed in a radially extending slot in a rotor body and is resiliently biased radially outwards by a spring in the base of the slot.

Conveniently, the outward end of each vane comprises a sealing element which ensures sealing abutment with the perimeter of the enclosure. Seals may also be incorporated within the sides of vanes, to further maintain a gas tight fit.

Preferably, a radially extending sealing element is provided in the perimeter of the rotor body midway between each adjacent pair of vanes. The sealing elements maintain a seal between the rotor body and the perimeter of the enclosure at the point contacts therebetween as the rotor rotates relative to the enclosure. Advantageously, the sealing elements are compressable radially and this ensures that they do not become caught between the rotor body and the perimeter of the enclosure. Advantageously, peripheral annular seals are incorDorated towards the etrerne circumference of the rotor to maintain a gas tight seal.

In segmented form these annular seals are laid into annular grooves in the rotor (one on each side) and have their extremities running against the vane abutment side seals, which are themselves doubly overlapped, for performance and serviceability. The annular seals are to prevent casing pressurisation don to the main shaft journals, leading to lube oil problems and considerable loss of power at ignition. They also prevent exhaust contamination of the main shaft journals between the sides of the rotor and the sides of the housing.

Preferably, the compressor comprises a compression chamber which is open to the primary compression chamber at one end and to the combustion chamber at the other end.

Advantageously, each end of the compression chamber is closed by a valve arrangement which is synchronised with the rotation of the rotor body to adnit air from the compression chamber during the compression part of the operating cycle and to release air during the combustion part of the operating cycle.

The valve arrangement may comprise a pair of cam operated valves each of which is positioned in a respective end of the compression chamber. The cam operated valves are driven by the rotor via belt, chain or the li'se.

Alternatively, the valve arrangement may corise a spring biased non-return valve in the inlet end of the compression chamber, a rotary valve in the outlet end of the compression chamber and a rotary compressor in the compressor chamber itself. The non-return valve opens when the pressure of air in the primary compression chanYer exceeds the spring bias closing it. The rotary compressor serves to further compress the air in the compression chamber over and above that which is possible by the vanes as they sweep towards the compressor inlet.

Advantageously, a fan turbine is provided in the gas/ air inlet to the primary compression chamber which draws air from outside the engine into the engine. Conveniently, this turbine fan is driven by a second turbine fan positioned in the exhaust outlet.

Advantageously, a plurality of rotary combustion engines in accordance withe present invention can be operated in parallel with one another, that is to say they can be mounted on a common shaft run together. In such an arrangement the phase difference between each rotor is approximately equal. Indexed, in such an arrangement it is possible to produce an engine vent in which the rotor of each engine comprises a single vane.

An embodiment of the present envention w | will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows a side view of a rotary combustion engine embodying the present invention with external casing cut away to illustrate the rotor arrangement and the internal valve arrangement; Fig. 2 shows a perspective view of the rotor assembly of a rotary combustion engine embodying the present invention; and Figs. 3 (a) to 3 (c) illustrate operation of a rotary combustion engine embodying the present invention with an alternative valving arrangement to that shown in Fig. 1.

Referring to Fig. 1 of the accompanying drawings there is shown a rotary combustion engine embodying the present invention. For ease of understanding the engine can be divided into three distinct sections. These are the exhaust driven turbo charger 1, the rotor assembly 2 and the compressor 3. All three sections are housed in a common housing 4 which, in common with other engines, defines a water jacket through which water can be circulated to cool the engine. Hose connections 5 and 6 are provided for the water jacket and a thermostat 7 is positioned in the return hose connection 6 to regulate the temperature of the engine in conventional fashion.

A cylinder head temperature sensor 8 is also provided in the wall of the water jacket which monitors the temperature of the engine and prevents overheating, again in conventional fashion.

The turbo charger 1 serves to introduce air and gas into the engine and comprises a ram air venturi choke tube 9 and a gas injector inlet 10, both of which lead to a chamber (not shown) in which is housed a turbine fan.

The turbine fan is driven on a common shaft by a second turbine fan 11 which is housed in a chamber 12 formed in the exhaust outlet 13 of the engine. As the second turbine fan 11 is driven round by the hot exhaust gases driven out through the exhaust outlet 13 it turns the other turbine fan which draws in the air and gas, and drives the mixture through a pipe 14 leading to the rotor 2.

The rotor 2 is housed within an eliptically shaped enclosure 15 defined by the housing 4. Referring now to Fig. 2 in conjunction with Fig, 1 it will be seen that the rotor 2 is rotatably mounted within the enclosure 15 on a shaft assembly 16. The rotor 2 is keyed to the shaft assembly 16 to prevent slippage and bearings 17 allow free rotation of the rotor 2 on the shaft assembly 16.

The rotor 2 itself comprises a solid, circular rotor body 18, the diameter of which is substantially the same as the narrowest dimension of the eliptically shaped enclosure 15. At its narrowest dimension the enclosure 15 orms to point contacts with the rotor body 18, but above and below the rotor body 18 there is defined a space. In the upper space there are provided twin sparkling plugs 19.

Equidistantly spaced around the perimeter of the rotor body 18 there are provided three vanes 20, 21 and 22.

Each vane 20, 21 and 22 is mounted within a slot 23 extending radially into the rotor body 18 and is resiliently biased outwards from the slot 23 by a spring 24.

At the free end of each vane 20, 21 and 22 there is provided a sealing element 25 and this is biased into sealing engagement with the perimeter of the enclosure 15. By virtue of the resilient bias provided by spring 24 the sealing member 25 of each vane 20, 21 and 22 maintains a sealing engagement with the perimeter of the enclosure 15 as the rotor body 18 rotates within it. Immediately behind each vane 20, 21 and 22, in the direction of rotation of the rotor body 18 within the enclosure 15, there is provided a V-shaped slot 26. This slot 26 collects fuel injected into the combustion chamber (defined hereinbelow) of the rotary combustion engine after primary and secondary compression of air only. This slot 26 allows the rotary combustion engine to operate at very high compression where gas is valved and is not delivered to the engine with the air because of the risk of pre-ignition.

Between the vanes 20, 21 and 22 the perimeter of the rotor body 18 is provided with a pair of peripheral annular seals 27 each of which engages with a respective side wall (not shown) of the enclosure 15 on each side of the rotor 2, and mid-way between each pair of adjacent vanes 20, 21 and 22 there is provided an intermediate sealing element 28 which extends radially outward from the rotor body 18 and is radially compressable. The annular seals 27 prevent casing pressurisation down to the shaft assembly 16 which would lead to lube oil problems and considerable loss of power at ignition. They also prevent exhaust contamination of the shaft assembly 16.The intermediate sealing elements 28 ensure that the rotor body 18 maintains a sealing engagement at the two points of contact with the enclosure 15, together with the peripheral annular seals 27.

Tt will be appreciated that as the vanes 20, 21 and 22 rotate through the spaces above and below the rotor body 18 they define enclosed chambers which increase and decrease in capacity. Referring to Fig. 1 which illustrates the engine at the end of its firing cycle it will be seen that between them vanes 20 and 21 define a first chamber 29 which is open to the exhaust outlet 13 and vanes 21 and 22 define a second chamber 30 which is open to the pipe 14. Between vanes 22 and 20 lies the point contact of the rotor body 18 with the enclosure 15 and this has the effect of forming two separate chambers 31 and 32 between these vanes above and below the point contact. Both chambers 31 and 32 are connected through a respective inlet 33 and outlet 34 to the compressor 3.

As shown in Fig. 1 the compressor 3 comprises a nonreturn valve 35 in the inlet 33 thereto. Air from the rotor 2 is forced under pressure past this non-return valve 35, as the vanes 20, 21 and 22 sweep the space below the rotor body 18, into a circular chamber 36 within which is eccentrically mounted a rotary compressor 37. An outlet pipe 38 from the chamber 36 leads to a second circular chamber 39, within which is mounted a rotary valve 40, and out of the compressor 3 through outlet 34 into the space above the rotor body 18. Both the rotary compressor 37 and the rotary valve 38 are driven by a cam wheel 41 mounted externally of the housing 4 on the end of the shaft assembly 16 via a common drive belt 42.Across the point contact between the enclosure 15 and the rotor body 18 there is provided a cross drilled regulator valve 43 which ensures that compressed air in the chamber 31 is harnessed freely to meter and drive pure gas fuel from supply into V-shaped groove behind vanes, prior to release of high pressure air at combustion chamber, prior to ignition.

Operation of the engine is such that the rotation of the rotor body 18, the rotary compressor and the rotary valve are all synchronised to a precise sequence of operations. This precise sequence of operation will be described with reference to Fig. 3, but since this-makes use of a different compressor operation of the compressor 3 of Fig. 1 will be described now.

As the vanes sweep the space below the rotor body 18 air is forced through the non-return valve 35 into chamber 36. Simultaneously, the rotary compressor 37 which is rotating in chamber 36 compresses the air towards the rotary valve 40 which remains closed until the rotary compressor 37 completes its sweep of the chamber 36. As the rotary valve opens the air within chamber 36 passes out of the compressor through outlet 34 into the space above the rotary body 18. Having been compressed the air is warmed and it picks up the charge of fuel carried behind the leading vane in the V-shaped slot 26. This mixture of compressed air and gas follow the leading vane forward and at the same time as the leading vane passes the twin sparking plugs 19 the rotary valve 40 closes and the twin sparking plugs 19 are fired to ignite the compressed air/ gas mixture.

Further description of the operation of the engine will now be continued with reference to Fig. 3. However, first it is necessary to describe the compressor 3 shown therein and briefly outline the most salient features of its operation.

Referring to Figs. 3 (a) to 3 (c) the engine is in all respects identical to that shown in Fig. 1, apart from the compressor 3. This comprises a single chamber 44 connected between the inlet 33 and the outlet 34 and closed at each end by a cam operated valve 45 and 46. In order that the compressor 3 is synchronised with the rotor 2 both cam operated valves 45 and 46 are driven from the rotor in the manner described hereinbelow with reference to Fig. 1.

In use, the oepration of the engine shown in Figs.

3 (a) to (c) is as follows: Initially, the rotor body 18 is turned by a small electric starter motor (not shown). As it begins to rotate a mixture of air and gas is directed through pipe 14 into the chamber 30 defined by vane 22 (Fig. 3 (c)). Air/gas continues to be dralrn into the chamber 30 until the next vane 21 passes pipe 14 at which point the chamber 30 is essentially closed between vanes 21 and 22.

As the leading vane 22 passes the inlet 33 to the compressor 3 the capacity of the chamber 30 begins to diminish and the air/gas within the chamber begins to compress. Of course, all the vanes 20, 21 and 22 are resiliently biased within their respective slot 23 and are accommodated within this slot 23 as the perimeter of the enclosure 15 gets closer to the rotor body 18. At a given point in the engine cycle cam operated inlet valve 45 opens (Fig. 3 (b) ) and the compressed air/gas within chamber 30 is admitted to the compressor chamber 44. As the vane 21 continues to get closer to the compressor inlet 33 the pressure within the compressor chamber 44 continues to increase and the air is warmed as a result of this continuing compression. Eventually, vane 21 passes the compressor inlet 33 and at this point the cam operated inlet valve 45 is closed.This is illustrated in Fig.

3(c) in which the altered reference numerals fo the vanes are shown in dotted lines.

As vane 21 travels across the island between the compressor inlet 33 and the compressor outlet 34 a fresh mixture of air and gas is drawn in through pipe 14 behind vane 20. Then, as the vane 21 passes the compressor outlet 34 the cam operated outlet valve 46 opens releasing the compressed air held in the compressor chamber 44 (Fig.3(a)).

This is released rapidly into the space behind vane 21 which is, of course, increasing in size as the vane moves forward, creating a vacuum, further inducing air/gas mixture in a rapid fashion.

As the vane 21 travels past the twin spare plugs 19 the cam operated outlet valve 46 closes and simultaneously the spark plug ignition occurs to ignite the air/gas mixture contained in combustion chamber 29. This is illustrated in Fig. 3 (b) in which the altered reference numerals for the vanes are shown in dotted line. As ignition occurs vane 21 is driven rapidly forward turning the rotor body 15 and the shaft assembly 16. Simultaneously, the cam operated inlet valve 45 opens and a further compression cycle begins. This compression cycle is assisted by the power assisted rotation of the rotor body 18 and it is no longer necessary to turn the rotor 2 with the electric starter motor.

As the gases in the chamber 29 expand as a result of combustion they drive vane 21 forward to the point where it passes the exhaust outlet 13 and the exhaust gases are allowed to escape to atmosphere. As they pass out through the exhaust outlet 13 they impinge upon the turbine fan 11 which is forced to rotate rapidly. As the turbine fan 11 rotates the turbine fan (not shown) between the choke tube 9 and pipe 14 drawing further air into the engine for the next compression/combustion cycle. Simultaneously, the following vane 20 is going through the combustion part of the compression/combustion cycle and it exerts a further turning force on the rotor body 18.

The compression/combustion cycle of operation continues for each vane for as long as the engine is run. As with a conventional engine, the speed of rotation is governed by metering the gas supply to the engine using a throttle arrangment.

The single engine unit described hereinabove can be used on its own where powder requirements are not unduly high. However, it is also possible with the engine of the present invention to connect a plurality of engine units onto a common shaft and run them together. With six engine units running together for example, an 18 cycle, low compression two stroke engine is provided, yet without the environmental penalties such as noise and pollution associated with a conventional two stroke engine.

It will be realised that the spring biases each vane into sealing engagement with the wall of the enclosure.

However, this radial biasing is also assisted by the circumferential forces exerted on the vanes as the rotor body turns and may be further assisted by the lube oil from the shaft/rotor bearings which is introduced behind the vanes by capillary tubes in the rotor body itself.

Claims

1. A rotary combustion engine comprising a housing defining an eliptically shaped enclosure, a substantially circular rotor rotatably housed within the enclosure and dividing the enclosure into a primary compression chamber and a combustion chamber, at least one radially biased vane mounted in the perimeter of the rotor and adapted in use to sweep each chamber as the rotor rotates within the housing, an inlet to said primary compression chamber for air and fuel, an outlet from said combustion chamber for venting exhaust gases, and a compressor whereby air introduced into the primary compression chamber is compressed during a compression part of the engine operating cycle and released into the combustion chamber during a combustion part of the engine operating cycle.

2. A rotary combustion engine according to claim 1, comprising a plurality of radially biased vanes, equilangularly spaced around the perimeter of the rotor.

3. A rotary combustion engine according to claim 2, comprising three equilangularly spaced radially biased vanes.

4. A rotary combustion engine according to any preceding claim, wherein each vane is housed in a radially extending slot in the rotor and is resiliently biased radially outwards therefrom by means of a spring in the base of the slot.

5. A rotary combustion engine according to any preceding claim, wherein a sealing member is provided at the end of each vane.

6. A rotary combustion engine according to any preceding claim, wherein sealing members are provided along the sides of each vane.

7. A rotary combustion engine according to any preceding claim, wherein a radially extending sealing element is provided in the perimeter of the rotor body midway between each adjacent pair of vanes.

8. A rotary combustion engine according to claim 7, wherein the sealing elements are compressible.

9. A rotary combustion engine according to any preceding claim, wherein the compressor comprises a compression chamber which is connected to the primary compression chamber at its inlet and to the combustion chamber at its outlet.

10. A rotary combustion engine according to claim 9, wherein the compression chamber comprises a valve arrangement which is synchronised with the rotation of the rotor to admit air to the compression chamber from the primary compression chamber during the compression part of the operating cycle and to exhaust air from the compression chamber to the combustion chamber during the combustion part of the operating cycle.

11. A rotary combustion engine according to claim 10, wherein the valve arrangement comprises a pair of cam operated valves each of which is positioned, respectively, in the inlet to and the outlet from the compression chamber.

12. A rotary combustion engine according to claim 10, wherein the valve arrangement comprises a spring biased non-return valve in the inlet to the compression chamber, a rotary valve in the outlet from the compression chamber and a rotary compressor in the compressor chamber itself.

13. A rotary combustion engine according to any preceding claim, wherein a fan turbine is provided in the gas/air inlet to the primary compression chamber which draws air into the engine.

14. A rotary combustion engine according to claim ly, wherein the fan turbine is driven by a second turbine fan locate in the exhaust outlet.

1. A plurality of rotary combustion engines according to any preceding claim mounted on a common drive shaft and operated in parallel with one another.

16. A plurality of rotary combustion engines according to claim 15, wherein the phase difference between each rotor is approximately equal.

17. A rotary combustion engine substantially as hereinbefore described with reference to the accompanying drawings.