AU4534499A - Rotary engine and compressor - Google Patents

Description

WO 99/63208 PCT/NZ99/00069 1 ROTARY ENGINE AND COMPRESSOR Technical Field This invention relates to engines and motors, and to compressors and pumps for compressing or pumping fluids. Background Art 10 A rotary type internal combustion engine or motor is disclosed in Patent Co operation Treaty International Application No. PCT/NZ93/00123. This form of engine has considerable advantages over conventional engines, particularly piston and cylinder type internal combustion engines, but has scope for improvement in some areas. 15 It is an object of the present invention to provide an engine, motor, compressor, or pump which will at least go some way toward overcoming the disadvantages of known constructions, or which will at least provide the public with a useful choice. 20 Disclosure of the Invention In one aspect the invention consists in an engine or motor comprising; a stator having inlet means for supply of a fluid or fluids to the engine or motor, and exhaust means for the removal of fluid or fluids from the engine or motor. 25 a rotor rotatably mounted relative to the stator, a moveable torque link arm means provided on the rotor, the torque link arm means in use providing a wall of an expansion chamber of the engine or motor, and an inner circumferential surface provided on the stator, the inner circumferential surface being profiled or contoured to provide an expansion path 30 means and a compression path means for expansion and compression phases of operation of the engine or motor.

WO 99/63208 PCT/NZ99/00069 2 In a further aspect the invention consists in an engine or motor comprising; a stator having inlet means for supply of fluids to the engine, and exhaust means for the removal of combusted or expanded fluids from the engine, a rotor rotatably mounted relative to the stator, 5 two pairs of moveable torque link arm means provided on the rotor, each pair of the torque link arm means providing walls of an expansion chamber or compression chamber of the engine or motor. In a further aspect the invention consists in a method of operating an engine or motor, the method comprising the steps of; 10 supplying an inlet fluid or fluids to a compression chamber of the engine or motor, walls of the compression chamber including parts of two moveable torque link arm means, varying the area of one wall of the compression chamber exposed to the inlet fluids relative to the area of at least one of the other walls of the compression 15 chamber so as to compress the inlet fluids, transferring the compressed fluids to a combustion or expansion chamber of the engine or motor, walls of the combustion or expansion chamber including parts of two moveable torque link arm means, igniting the compressed fluids, and 20 varying the area of one wall of the combustion chamber exposed to said fluids as said fluids relative to the area of at least one of the other walls of the combustion chamber constant so as to provide a required torque characteristic. In a further aspect the invention consists in a stationary housing for housing an engine, motor or compressor, the housing comprising a central casing having 25 an inner circumferential surface, a part of the inner surface being profiled or contoured to provide a first expansion or compression path means and another part being profiled or contoured to provide a second expansion or compression path means, the remainder of the inner surface being of a different profile or contour to the first surface and the second surface, the first and second surfaces 30 being profiled or contoured so that two moveable torque link arm means provided WO 99/63208 PCT/NZ99/00069 3 on the rotor are progressively moved relative to the rotor during at least a part of the operating cycle of the engine or compressor. In a further aspect the invention consists in a rotor for an engine, motor or compressor, the rotor comprising a body, a support means for mounting the body 5 relative to a stationary housing of said engine or compressor so as to allow relative rotational movement between the body and the housing, the body having a two pairs of moveable torque link arm means thereon at least parts of which provide walls of an expansion chamber and/or a compression chamber of the engine or compressor. 10 In a further aspect the invention consists in apparatus for compressing or pumping fluids, comprising; a stationary housing according to the preceding statement of invention, a rotor rotatably mounted relative to the stator, two moveable torque link arm means provided on the rotor, the torque link 15 arm means both providing walls of a compression chamber of said compressor or pump. To those skilled in the art to which the invention relates many changes in construction and widely differing embodiments will suggest themselves without departing from the invention as defined in the appended claims. The disclosures 20 and descriptions herein are purely illustrative and are not intended to be in any sense limiting. The invention consists in the foregoing and also envisages constructions of which the following gives examples. 25 Brief description of the drawings Preferred forms of the present invention will now be described with reference to the accompanying drawings in which: 30 Figure 1 is a diagrammatic side elevation in cross section of an internal combustion engine; WO 99/63208 PCT/NZ99/00069 4 Figure 2 is an isometric view of a moveable torque link arm of the engine of figure 1; Figure 3 is a side elevation of the torque link arm shown in figure 2, showing part of the seal assembly; 5 Figure 4 is a partial side elevation of an alternative torque link arm to that shown in figures 2 and 3; Figure 5 is an exploded end elevation of another alternative torque link arm and sealing arrangement; Figure 6 is an end elevation of an optional guiding cam for use with the 10 torque link arms of the preceding figures; Figure 7 is a partial side elevation of the torque link arm shown in figure 5; Figure 8 is a diagrammatic side elevation and cross-section of an internal combustion engine in accordance with the present invention at the point of ignition in a normal cycle of operation of the engine; 15 Figure 9 is a diagrammatic side elevation of the engine of Figure 8 with the engine of that figure shown during an expansion or combustion phase of the operation of the engine; Figure 10 is a diagrammatic side elevation and cross-section of the engine of figures 8 and 9 shown in a phase of operation immediately preceding exhaust; 20 Figure 11 is a diagrammatic side elevation and cross-section of the engine of figures 8 to 10 shown in a phase of operation corresponding to the end of the exhaust phase and beginning of an inlet phase; Figure 12 is a diagrammatic side elevation and cross-section of the engine of figures 8 to 11 shown in a cycle at the end of the inlet phase; 25 Figure 13 is a diagram of the operating cycle of the engine of figures 8 to 12; Figure 14 is a diagram of the possible geometry of the stator of the engine of figures 8 to 13; Figure 15 is a diagrammatic side elevation and cross-section of a further 30 alternative embodiment of an internal combustion engine in accordance with the present invention.

WO 99/63208 PCT/NZ99/00069 5 Best Modes of Carryinq out the Invention Referring to figure 1, an engine or motor that may be used as an internal combustion engine is shown, generally referenced 100. The engine 100 may be 5 generally referred to as a Variable Geometry Rotary Engine, and is in some respects similar to my engines described in International applications PCT/NZ93/00123 and PCT/NZ96/00103. The engine has a stationary housing or stator 101 and a rotor 102, which is rotatably mounted relative to the stator 101. The rotor has an output shaft 104. The normal direction of rotation of the shaft 104 10 and the rotor is indicated by arrow 106. The stator 101 has holes 108 and 110 about the periphery thereof. Holes 108 may be used to stack engines and/or compressors together, and holes 110 are used to attach front and rear end plates to each engine as will be described further below. The stator also has cooling fins 112, which are preferably disposed about most, or the entire outer periphery of the 15 stator. Depending on the cooling method adopted, cooling fins 112 may not be required, as the engine may be cooled by any desirable method, for example liquid cooling. Holes 114 are provided in output shaft 104, and in rotor 102, and in use contain bolts for fixing the shaft to the rotor. The rotor has two moveable torque 20 link means 116 and 118 which are leading and trailing torque link arms, respectively, and which are pivotally connected to rotor 102 by pins or the like 120 and 122. Torque link arms 116 and 118 are biased against inner walls of the stator so that the torque link arms "wipe" inner surfaces of the stator. A number fo biassing methods may be used. The preferred biasing method is profiled grooves 25 on an inner side wall of the end caps of the stator casing as described further below. As can be seen from figure 1, recesses are provided in the rotor 102 to allow the torque link arms to move generally radially relative to the rotor as the rotor rotates relative to the stator. Referring to figure 2, one of the torque link arms 116 and 118 is shown in 30 isometric view for clarity.

WO 99/63208 PCT/NZ99/00069 6 The preferred torque link arm sealing arrangement is shown in figure 3, in which a button seal 128 is shown and which is in use located in edge 130 of the torque link arm. The button seal contains a leaf spring 132 or other form of biasing means which biases a torque link arm edge seal 134 against the inner surfaces of 5 the stator 101. One or more holes 136 may be provided in the torque link arms to reduce their mass. The torque link arm of figure 3 has side surfaces 138 which are preferably machined sufficiently accurately to provide a seal between the torque link arm and the front and/or rear end caps of the engine. Therefore, only one of seals 128 and 10 134 are required on each torque link arm. However, in some applications, the desired quality of the sealing surface on side surfaces 138 may not be able to be achieved, in which case the alternative shown in figure 4 may be used. As can be seen from figure 4, a further button seal 140 is provided which contains a further spring and edge seal (not shown), and a side seal 142 is provided between the two 15 button seals. Referring to figure 5, the button spring 144, which holds button seal 130 in contact with the front and/or rear end plates is shown together with another alternative sealing method which comprises a torque link arm end cap 146 which is biased against the front and/or rear end plates of the engine by spring 148. The 20 cap is machined to provide a seal. Figure 6 shows a cam 150 which is provided on a part of the torque link arm, for example on the central web of the torque link arm, for guiding the torque link arm relative to the stator inner surface by means of a corresponding cam profile in one or both end plates of the stator. This arrangement is the preferred 25 method of mechanically controlling the arms relative to the inner stator surfaces, as the mass of the rapidly rotating torque link arms can impose unacceptably high forces on the seals 134. Thus the position of the arms relative to the stator can be controlled throughout the operating cycle of the engine so seals 143 can float within the ends of the arms 116 and 118. The cam 150 is shown within a ball race 30 152 so that it may move relative to a groove provided in a wall of the front or rear WO 99/63208 PCT/NZ99/00069 7 end plates of the engine. In this arrangement the torque link arm load is carried by the front or rear end plates rather than the seals 134. Figure 7 shows a side elevation of the torque link arm end cap 146 of figure 5. 5 Referring again to figure 1, the rotor 102 has button seals 156 and 158 that contain edge seals 160 and 162. Between these seals, an edge seal 164 is provided. As will be seen from the following description, the position of the pivotal attachment of the torque link arms to the rotor provides maximum rotational moment, and the rotor as a whole has sufficient inertia to eliminate the need for a 10 flywheel. In the position shown in figure 1, the engine is part way through the expansion or combustion phase of the engine operating cycle. Torque link arm 116 has moved radially pivotally away from the centre of rotor 102 as it follows the contour of the profiled inner surface 166 of the stator which in figure 1 extends from 15 Top Dead Centre (TDC) at 168 to point 172. Combustion occurs until exhaust which is located at point 170, but could be varied with variations in engine design. The remainder of the inner surface, which is preferably concentric, and almost conterminous with the outer periphery of the body of the rotor 102, is referenced 174. The angular extent of the surfaces 166 and 174 can be varied as long as seal 20 134 of the trailing torque link arm 118 is in contact with surface 174 while the leading torque link arm 116 is in the combustion phase between the point of ignition and exhaust. The working chamber, which may also be referred to as the combustion chamber or expansion chamber, is effectively provided between the sealing edge 25 surfaces of torque link arms 116 and 118, seals 128 and 134 of each torque link arm, seals 156, 158, 160, 162 and 164, and the inner surfaces 170 and 174. The edge seal 164 is preferably curved so that its edge is not concentric with the rotor to prevent it wearing a groove in the inner surfaces of the end caps. A combustion region or "cell" 165 is provided in the rotor to assist proper combustion. Positioning 30 the combustion cell in the rotor, rather than the stator, provides the advantage that there is no space in the stator from which combusted gases are difficult to extract.

WO 99/63208 PCT/NZ99/00069 8 As can be seen from figure 1, the area 176 of leading torque link arm 116 that is exposed to combusting gases is much greater than the area of the trailing torque link arm between seals 162 and 134 that is exposed. Therefore, the rotor will move in the direction of arrow 106. 5 Referring to figure 8, an embodiment of the present invention is shown which includes two profiled or contoured paths on the inner circumferential surface of the stator. Figures 8 to 12 use the same reference numerals as those used in the preceding figures to denote the same or similar features. In use of the embodiment of figure 8 as an engine or motor, the combustion chamber or 10 expansion chamber is effectively provided between the sealing edge surfaces of torque link arms 116 and 118, seals 128 and 134 of each torque link arm, seals 156, 158, 160, 162 and 164, and the inner surfaces of 170 and 174. In the position shown in figure 8, compressed inlet gases are contained within the working chamber and ignition has just occurred. 15 Referring now to figure 9, it will be seen that the rotor has rotated from the position shown in figure 8 to that shown in figure 9. The area 176 of leading torque link arm 116 that is exposed to combusting gases in the chamber is now much greater than the area of the trailing link arm between seals 162 and 134 that is exposed to the combusting gases. Therefore, the rotor will move in the 20 direction of arrow 106. The profile of the expansion path 166 departs from an axis of rotation which is concentric with that of the output shaft to allow the area 176 of the leading torque link arm to become progressively greater as the rotor rotates through the combustion cycle. The profile of the inner circumferential surface 74 of the stator may be varied so as to provide the engine with a required 25 torque characteristic during the combustion or expansion phase. The present embodiment of the invention also allows required compression parameters to be satisfied as will be explained further below. Referring to figure 10, the rotor is shown in a position at the end of the combustion phase of the engine cycle. Seal 134 of the leading torque link arm 30 116 is at a position where it is about to allow the combusted gases to exit the stator through exhaust port 180. Once the seal passes the exhaust port, the WO 99/63208 PCT/NZ99/00069 9 combusted gases exit the combustion chamber through the exhaust port, and the trailing torque link arm 118 "sweeps" the combustion chamber to ensure that the gases are extracted. Turning to figure 11, the leading torque link arm 116 has now passed the 5 inlet port 165, so that inlet gases may enter the space between the two torque link arms and the associated seals. It will be seen that there is some overlap between gases being allowed to enter the inlet port and gases exiting the exhaust port. This period of overlap allows flow of gases through the confined space between the two torque link arms. Thus, as the inlet gases enter the 10 confined space, they assist the exhaust gases in their exit path through the exhaust port. It will be seen that at the beginning of the inlet cycle, both torque link arms are essentially in a substantially circular portion 182 of the inner stator surface centred on the axis of rotation of the rotor. As the inlet cycle progresses, the leading torque link arm 116 begins to move into a second profiled or 15 contoured portion 167 of the stator inner circumferential surface during which the exposed area 176 of the leading torque link arm 116 increases whilst that of the remaining torque link arm remains substantially constant. Accordingly, the volume of the second working chamber increases, drawing in inlet gases. Referring to figure 12, the end of the inlet cycle is shown as seal 134 of 20 the trailing torque link arm 118 passes over the exhaust port 180 to close the exhaust port and therefore stop further inlet gases entering the second working chamber. It will be seen that as the rotor returns to the position shown in figure 8, the area 176 of the leading torque link arm 116 will remain substantially constant, while that of the trailing torque link arm 118 will reduce. This effectively 25 reduces the volume of the second working chamber and therefore compresses the combustible gases that have entered through the inlet port so that they are compressed and ready for the ignition and combustion phase of the engine cycle. Thus the cycle repeats as described with reference to figure 8. Referring now to figure 13, it will be seen that the four phases of the 30 operating cycle of the engine described with reference to figures 8 to 12 may be illustrated diagrammatically. Each phase my be shown as having a duration of WO 99/63208 PCT/NZ99/00069 10 approximately 90 degrees of rotor revolution, so that a complete cycle of operation occurs in one rotor revolution of 360 degrees. Thus beginning at Top Dead Centre (TDC) 300 in figure 13, which is for the purposes of the figure taken to be the point at which ignition occurs, the combustion or power phase 302 5 begins and lasts for 90 degrees of rotor rotation. The point in the combustion phase at which maximum torque occurs will depend upon the contour of the expansion path 166 formed in the inner stator surface, but is likely to be between 30 degrees and 45 degrees after TDC. The exhaust phase 304 begins after completion of the combustion phase, 10 and similarly lasts for approximately 90 degrees of rotor rotation after which the intake phase 306 begins. As previously mentioned, there is in use some overlap between exhaust and inlet phases, and there may also be overlap between the other phases of operation. The inlet phase lasts for approximately 90 degrees after which the 15 compression phase 308 begins and lasts the remaining 90 degrees until the rotor returns to TDC ready for another combustion phase. Turning to figure 14, a schematic is shown which provides an example of stator design to achieve desired engine, motor, compressor or pump parameters. Outer circle 320, having a centre 322 represents the minimum inner diameter of 20 an initial piece of material (e.g. aluminium alloy) from which the stator housing is to be constructed. The diameter of the inner stator circumferential surface centred on the axis of rotation of the rotor (i.e. about centre 322) is shown as circle 324. The first and second expansion paths can then be designed by drawing first and second circles 326 and 328 respectively which have centres 25 330 and 332 offset from centre 322 at an angle of 45 degrees for example. The extent of the offset is such that the offset circles do not extend beyond the circumference of outer circle 320. The difference in area between circle 324 and each offset circle provides an indication of the volume of each expansion path. For offset circle 326 this volume is shown by shaded area 334. 30 Accordingly the engine disclosed has the significant advantage that compression and combustion are all performed within one 3600 cycle of the WO 99/63208 PCT/NZ99/00069 11 engine without any separate compressor means being required to supply the engine with compressed gases. Referring to figure 15, a further alternative embodiment is shown. Figure 15 uses the same reference numerals as those used in preceding figures to denote 5 the same or similar features. The difference in the construction shown in figure 15 from those described above is the use of two pairs of torque link arms. Each torque link arm in a pair provides a leading torque link arm and a trailing torque link arm. The rotor can be described by referring to it as two substantially symmetric parts, generally referenced A and B in figure 15. Thus in figure 15 part A has a 10 leading torque link arm 116A and a trailing torque link arm 118A. Similarly part B has a leading torque link arm 116B and a trailing torque link arm 118B. Each pair of torque link arms are mounted on pivotable or rotatable mountings 350 and 352 which allow each arm to follow the contour of the inner circumferential surface of the stator housing. The operation of each of the parts A and B is the same as 15 described above with reference to figures 8 to 14, but there are two pairs of arms, so the work performed in each cycle will be doubled. As can be seen from the description for the operation of the embodiments of the preceding figures, the effect of the rotor construction shown in figure 15 is to double the expansion or compression phases for each physical 360 degree 20 rotation of the rotor. This will at least in theory double the torque and double the power output of the engine at a given speed. If the construction is being used as a compressor, the volume of compressed fluids provided will be doubled. It will be seen that the rotor could be further modified to provide three or more pairs of torque link arms to provide further increases in engine or compressor performance. 25 It will also be apparent that the rotor construction shown in figure 15 could be applied to the stator construction shown and described with reference to figures 8 to 12. Such a combined construction would have the advantages of two complete operating cycles occurring in one physical 360 degree rotation of the rotor.

Claims (10)

1. An engine or motor including; 5 a stator having inlet means for supply of a fluid or fluids to the engine or motor, and exhaust means for the removal of fluid or fluids from the engine or motor, a rotor rotatably mounted relative to the stator, a moveable torque link arm means provided on the rotor, the torque link arm means in use providing a 10 wall of an expansion chamber of the engine or motor, and an inner circumferential surface provided on the stator, the inner circumferential surface being profiled or contoured to provide an expansion path means and a compression path means for expansion and compression phases of operation of the engine or motor. 15

2. An engine or motor as claimed in claim 1 wherein two moveable torque link arms are provided on the rotor, each torque link arm in use providing a wall of an expansion chamber of the engine or motor. 20

3. An engine or motor as claimed in claim 1 or claim 2 wherein two pairs of moveable torque link arms are provided on the rotor, each pair of torque link arms in use providing walls of an expansion chamber or compression chamber of the engine or motor. 25

4. An engine or motor as claimed in any one of the preceding claims wherein the expansion path means in use forms part of a combustion chamber of the engine or motor. WO 99/63208 PCT/NZ99/00069 13

5. An engine or motor as claimed in any one of the preceding claims wherein the compression path means in use forms part of a compression chamber of the engine or motor. 5

6. An engine or motor as claimed in any one of the preceding claims wherein the torque link arm sealably contacts inner surfaces of the stator including the expansion and compression path means.

7. An engine or motor as claimed in any one of the preceding claims wherein 10 the four phases of inlet, compression, combustion and exhaust all occur within 360 degrees of engine operation.

8. A pump or compressor comprising the engine or motor of any one of the preceding claims wherein an outlet is provided for compressed gases to allow 15 escape of compressed gases at the end of each compression phase.

9. A method of operating an engine or motor as claimed in any one of the preceding claims, the method comprising the steps of; supplying an inlet fluid or fluids to the compression chamber of the engine or 20 motor, walls of the compression chamber including part of at least one moveable torque link arm means, varying the area of one wall of the compression chamber exposed to the inlet fluids relative to the area of at least one of the other walls of the compression chamber so as to compress the inlet fluids, 25 transferring the compressed fluids to a combustion or expansion chamber of the engine or motor, walls of the combustion or expansion chamber including part of at least one moveable torque link arm means, igniting the compressed fluids, and varying the area of one wall of the combustion chamber exposed to said 30 fluids as said fluids relative to the area of at least one of the other walls of the combustion chamber so as to provide a required torque characteristic. WO 99/63208 PCT/NZ99/00069 14

10. Any new feature or combination of features disclosed herein.