AU2017101231A4 - A Rotary Engine with Wear Plate - Google Patents

Abstract

A rotary engine with wear plate, the rotary engine including a number of casing plates including at least a front plate, a rear plate and at least one rotor housing plate having an opening in which a rotor rotates, at least one of the front plate or the rear plate includes a shaped recess and a correspondingly shaped removable wear plate provided in the shaped recess and against which the rotor rotates. Figure 3

Description

A ROTARY ENGINE WITH WEAR PLATE TECHNICAL FIELD

[0001] The present invention relates to engines and particularly to a rotary engine formed from a series of one or more rotor housings, separated by plates or billets and having at least one replaceable wear plate.

BACKGROUND ART

[0002] In general, rotary engines are well known. The great advantage of a rotary engine is that because there are no reciprocating parts, only rotating parts, a rotary engine can be manufactured that is lighter, more compact and has fewer moving parts than a piston engine.

[0003] Historically, rotary engines have had a fixed casing with an internal shape of a wide waisted figure-of-8 and a near triangular rotor. For higher power, a rotary engine can be provided with two or more rotors phased together. The output shaft, centrally located through the rotors typically rotate at approximately three times the rotor speed. The rotor revolves eccentrically within the casing in such a way that the three rotor tips are continually in contact with the internal surface. Planetary gearing connects the rotor to an output shaft which is equivalent to the crankshaft of a piston engine.

[0004] A more recent development to the well-known rotary engine is the replacement of the fixed casing of the rotary engine with a casing formed from a series of casing plates which are typically machined to either house a rotor (rotor housing plate), be a front plate or a rear plate (end plate) or be a central plate which is used to space rotors from one another in engines having two or more rotors. An example of this type of engine is illustrated in Figure 1 with a centre plate from this type of engine illustrated in Figure 2.

[0005] The plates in this type of engine are typically manufactured of a lightweight material such as aluminium, for example. Unfortunately, lightweight materials are generally softer than the more dense materials that were used historically. This means that the newer types of engines with plates formed from materials which are lighter in weight, typically experience more wear than conventional rotary engines and wear leads to a gradual lessening in performance until the entire plate having the wear surface requires replacement.

[0006] Another issue with rotary engines is the efficiency of the seals provided in the rotary engine. Most rotary engines are water cooled engines with oil cooling facilities for the rotor. This means that the water used to cool the engine should be kept separately from any lubricant such as oil which is used to lubricate the engine as mixing of the water and lubricants results in loss of efficiency and catastrophic engine failure.

[0007] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

SUMMARY OF INVENTION

[0008] The present invention is directed to a rotary engine with wear plates, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0009] With the foregoing in view, the present invention in one form, resides broadly in a rotary engine with one or more wear plates, the rotary engine including a front plate, a rear plate and at least one rotor housing plate having an opening in which a rotor rotates, at least one of the front plate or the rear plate includes a shaped recess and a correspondingly shaped removable wear plate provided in the shaped recess and against which the rotor rotates.

[0010] Typically, where a rotary engine has two or more rotors, at least one centre plate is provided to separate the rotors. In this case, the centre plate will typically be provided with at least one and normally a pair of shaped recesses, one on either side of the centre plate and a correspondingly shaped removable wear plate provided in each shaped recess and against which a rotor rotates. These side/end plates typically have openings in them (referred herein as ports)to allow for the flow of gasses into and out of the rotor chambers as part of the internal combustion cycle.

[0011] In an alternative aspect, the present invention resides in a replaceable wear plate for a rotary engine, the replaceable wear plate configured as a wide-waisted figure of 8 shape and manufactured of a wear resistant material, configured to be located relative to at least one of a front plate, a rear plate or a centre plate of a rotary engine.

[0012] In a preferred embodiment of the invention the wear plate is removable and replaceable if required.

[0013] In a preferred embodiment, the rotary engine will be formed from a number of juxtapositioned housing plates, and end/centre plates, which are fastened together to form an engine casing. Typically, there will be at least a front plate and a rear plate. Each rotor is preferably provided within a rotor housing plate which includes a shaped opening in which the rotor rotates and the rotor typically rotates against a wear surface provided either side of the rotor housing plates.

[0014] In the case of a rotary engine with a single rotor, a rotor housing plate is sandwiched between the front plate and the rear plate, each of the front plate and rear plate has a wear surface.

[0015] In the case of a rotary engine with two or more rotors, a rotor housing plate is sandwiched adjacent to the front plate by a centre plate and a second rotor housing plate is sandwiched between the rear plate and a centre plate. If it is a two-rotor engine, a single centre plate is provided having a wear surface on both sides. If more than two rotors are provided, then more centre plates are provided with the number of centre plates typically being one less than the number of rotors provided. Each centre plate typically has a wear surface on both sides.

[0016] In a particularly preferred embodiment, each of the plates of the rotary engine are formed from machining the required shape of the plate from a single block or billet of metal. One particularly preferred metal which could be used is aluminium.

[0017] In use, the plates of the required rotary engine are located relative to one another and then attached together, typically using elongate tensile fasteners such as bolts. Attaching the plates to one another will typically sandwich the rotors in position between a pair of adjacent wear surfaces whether provided on the front plate, the rear plate or one or more centre plates.

[0018] One or more seals or gaskets are preferably provided between adjacent plates in order to allow a liquid, typically water to cool the engine during operation. One or more seals or gaskets are also provided in appropriate locations to ensure that any lubricant such as oil used to lubricate rotating parts of the engine does not mix with the cooling liquid. It is important that appropriate fluid envelopes are formed within the engine so that the cooling liquid does not mix with any lubricant.

[0019] At least one, and typically a pair of cooling liquid channels are provided in each of the plates. The cooling liquid channels provided in each of the plates will typically be in fluid communication with one or more cooling assemblies.

[0020] In particular, the cooling assembly or configuration is preferably provided in relation to each plate, beneath the recess into which the replaceable wear plate is located allowing cooling liquid to flow behind the replaceable wear plate to cool the wear plate. Again however it is preferred that one or more seals or gaskets be provided to maintain the cooling liquid in the cooling assembly or configuration and prevent the cooling liquid from access to the central opening through the plate in which the output shaft rotates and also preventing the cooling liquid from access to the intake/exhaust port.

[0021] Preferably, each of the plates provided in the rotary engine of a preferred embodiment of the present invention includes a shaped recess provided into the plate and into which the correspondingly shaped removable wear plate is provided. The shaped recess will typically correspond in size, shape and depth to the wear plate. In a preferred embodiment, the recess will typically have an arcuate upper and lower edge and a pair of opposed, substantially parallel side edges. As mentioned above, a bore is typically provided through each of the plates for the output shaft. In a preferred embodiment, the recess will be approximately 6 mm in depth which corresponds to the preferred thickness of the wear plate of 6 mm. As mentioned above, the cooling assembly configuration is typically provided beneath the recess with the recess being defined and its periphery by a peripheral edge but with a number of support wedges being provided within the recess in order to support the wear plate in the recess. Each of the preferred support wedges typically has a substantially coplanar outer or upper surface forming the base of the recess. The support wedges will typically be spaced from one another to allow cooling liquid to flow between the wedges and access the rear surface of the wear plate.

[0022] Preferably, a raised portion is provided in one quadrant of the recess and the intake/exhaust port is preferably provided through the raised portion. The raised portion will typically be shaped to correspond with a pocket formed in a rear surface of each wear plate.

[0023] Preferably, the raised portion is at a different height to the support wedges upon which a rear surface of the wear plate preferably rests. In a preferred form, the port pocket formed in a rear surface of each wear plate will preferably be approximately 2 mm in depth. A gasket or seal seating groove will preferably be provided concentrically within the perimeter of the raised portion and about the intake/outlet port in order to prevent any of the cooling water accessing the intake/outlet port.

[0024] Preferably, a number of attachment openings are provided about the central bore on the plate in order to receive fasteners there into to attach the wear plate at least temporarily relative to the recess.

[0025] An inlet/exhaust port is typically provided as mentioned above in the raised portion of the plate in fluid communication with an inlet and/or exhaust port provided through a side edge of the plate. Therefore, an inlet end/or exhaust port provided through a side edge of the plate will normally communicate with a shaped channel through the plate in order to communicate with the inlet/exhaust port provided in the raised portion of the plate and further with a port provided through the wear plate.

[0026] Each wear plate, and typically there will be more than one wear plate provided in any single rotary engine, will normally have the same configuration. In particular, a pair of wear plates will normally be provided for each rotor provided in the rotary engine, one wear plate to abut each lateral side of the rotor during rotation. Typically, the rotors will rotate within the opening provided in the rotor housing plate directly abutting the wear plate on either lateral side.

[0027] The wear plates will typically have higher wear resistant properties then the generally softer material used to form the plates of the rotary engine. One preferred material for use to form the wear plates is cast-iron or similar. The material used may be treated to increase/maximise the wear resistance of the wear plate.

[0028] Each wear plate will typically be substantially planar, of consistent thickness across its dimension except for the preferred port pocket provided in one quadrant. As mentioned, the preferred port pocket will typically be approximately 2 mm in depth and the intake/outlet port will typically be located within, through the port pocket. Each wear plate will typically have 2 main surfaces substantially parallel with one another, one being the wear surface which is oriented outwardly away from the plate relative to which the wear plate is mounted and against which the rotor rotates and a rear surface which is oriented toward the plate relative to which the wear plate is mounted. The wear surface will preferably be substantially planar and smooth.

[0029] A central opening will typically be provided through the wear plate. The central opening will typically be arcuate, generally circular with a number of attachment openings provided around the periphery of the central opening in order to receive the elongate tensile fasteners to attach the wear plate relative to the plate.

[0030] The wear plate will typically be shaped to correspond with the recess in the plate relative to which it is to be attached and preferably, the wear plate will have an arcuate top and bottom edge and a pair of substantially parallel, planar spaced apart side edges. As mentioned above, it is preferred that the wear plate be approximately 6 mm in thickness.

[0031] Preferably, a peripheral groove to seat a seal or gasket at least partially therein will preferably be provided concentrically within the outer perimeter of the wear plate. Normally the peripheral groove will be provided into the surface opposite the wear surface side of the wear plate, in other words “the rear surface”.

[0032] As mentioned above, a shaped recess is preferably provided in one quadrant of the wear plate into the rear surface in order to form a port pocket. Typically, the intake/outlet port communicates with an opening through the port pocket. Typically, the opening will be shaped to correspond with the intake/outlet port in the raised portion of the plate relative to which the port pocket is located during attachment of the wear plate relative to the plate.

[0033] The opening may taper from the rear surface to the wear surface either converging or diverging.

[0034] A groove or similar structure may be provided extending about the periphery, preferably concentrically within the periphery of the port pocket in order to seat a seal or gasket at least partially therein.

[0035] The spacing between the opening in the port pocket and any groove or similar structure provided to seat a seal or gasket is important in maintaining sufficient material thickness therebetween to form an effective seal whilst not weakening the wear plate in the particular region.

[0036] The provision of a replaceable wear plate allows for reduction in the weight of a rotary engine by forming the bulk of the engine from lightweight materials such as aluminium for example but providing where resistant properties in the positions where this functionality is required to allow the rotor to rotate against a where resistant wear plate to maintain longevity of service life. In circumstances where the wear plate begins to wear and the performance of the engine begins to suffer, the engine can be dismantled and the wear plate(s) replaced easily rather than replacing one of the plates used to form the engine itself such as the front plate, the rear plate or one or more centre plates. This dramatically reduces the cost in servicing the engine whilst not sacrificing performance.

[0037] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

[0038] The reference to any prior art in this specification is not, and should not be taken as an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge.

BRIEF DESCRIPTION OF DRAWINGS

[0039] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows: [0040] Figure 1 is an isometric view of a prior art rotary engine formed from a series of plates and having two rotors located on either side of a centre plate.

[0041] Figure 2 is an isometric view of a centre plate from an engine such as that illustrated in Figure 1 showing the centre shaft and wear surface against which the rotor rotates.

[0042] Figure 3 is a front elevation view of a centre plate according to a preferred embodiment of the present invention.

[0043] Figure 4 is a front elevation view of an external surface of a rear plate according to a preferred embodiment of the present invention.

[0044] Figure 5 is a front elevation view of a rear plate according to a preferred embodiment of the present invention with the wear plate removed.

[0045] Figure 6 is an isometric view of the centre plate illustrated in Figure 5.

[0046] Figure 7 is an angled view of the centre plate illustrated in Figure 6.

[0047] Figure 8 is a detailed isometric view of the portion illustrated in Figure 6 and identified by reference letter A.

[0048] Figure 9 is a detailed view of the port pocket from the wear plate illustrated in Figure 11 and identified by reference B.

[0049] Figure 10 is a front elevation view of a wear plate according to a preferred embodiment of the present invention showing the wear surface.

[0050] Figure 11 is an elevation view of the wear plate illustrated in Figure 10 from the reverse side.

DESCRIPTION OF EMBODIMENTS

[0051] According to a particularly preferred embodiment of the present invention, a rotary engine 10 with wear plate is provided.

[0052] The rotary engine 10 of the preferred embodiment will have an external appearance and general construction similar to that illustrated in Figure 1.

[0053] The rotary engine 10 includes a front plate 11, a rear plate 12 and a pair of rotor plates 13 each having an opening in which a rotor rotates. The engine illustrated in Figure 1 has two rotors, and therefore, a centre plate 14 is provided to separate the rotor plates and the rotors they contain.

[0054] In the preferred embodiment, rather than the unitary plate illustrated in Figure 2 (this is a centre plate but the conventional front plate and rear plate have a similar configuration), the front plate 11 and the rear plate 12 each includes a shaped recess 15 (best illustrated in Figure 6 and 7) and a correspondingly shaped removable wear plate 16 (best illustrated in Figures 10 and 11) provided in the shaped recess 15 and against which the rotor (not shown) rotates.

[0055] In this case, the centre plate 14 (illustrated better in Figure 3) will typically be provided with a pair of shaped recesses 15, one on either side of the centre plate 14 and a correspondingly shaped removable wear plate 16 provided in each shaped recess 15 and against which a rotor rotates.

[0056] The replaceable wear plate of the preferred embodiment is configured as a wide-waisted figure of 8 shape and manufactured of a wear resistant material A wear plate will normally be located relative to the front plate 11, rear plate 12 and both sides of the centre plate 14of a rotary engine.

[0057] Each rotor (not shown) is provided within a rotor plate 13 which includes a shaped opening in which the rotor rotates and the rotor typically rotates against a wear surface of the wear plate 16 on either side of the rotor plate. In effect, the wear plates on either side of the rotor plate confine the rotor to rotation within the opening in the rotor plate 13 and prevent any lateral movement.

[0058] In the case of a rotary engine with two rotors as illustrated in Figure 1, a rotor housing plate 13 is sandwiched adjacent to the front plate 11 by a centre plate 14 and a second rotor housing plate is sandwiched between the rear plate 12 and a centre plate 14. A single centre plate 14 is provided having a wear plate 15 provided on both sides of the centre plate 14.

[0059] In a particularly preferred embodiment, each of the casing plates of the rotary engine (the front plate 11, the rear plate 12, any rotor housing plate 13 and any centre plate 14) are formed from machining the required shape of the plate from a single block or billet of metal. One particularly preferred metal which could be used is aluminium.

[0060] In use, the casing plates of the rotary engine are located relative to one another and then attached together, typically using elongate tensile fasteners such as bolts through aligned openings in the casing plates and into threaded openings 17 in the rear plate 12 as illustrated in Figure 6. Attaching the plates to one another will typically sandwich the rotors in position between a pair of adjacent wear surfaces whether provided on the front plate 11, the rear plate 12 or one or more centre plates 14.

[0061] One or more seals or gaskets are preferably provided between adjacent casing plates in order to allow a liquid, typically water to cool the engine during operation. A seal seating groove 18 is provided concentrically within the perimeter of the casing plates to seat a perimeter seal (not shown) to help seal the casing plates relative to one another. One or more seals or gaskets are also provided in appropriate locations to ensure that any lubricant such as oil used to lubricate rotating parts of the engine does not mix with the cooling liquid. It is important that appropriate fluid envelopes are formed within the engine so that the cooling liquid does not mix with any lubricant.

[0062] A pair of cooling liquid channels 21 is provided in each of the casing plates, preferably in a perimeter portion which are in turn connected to a fluid supply system. The cooling liquid channels 21 provided in each of the casing plates will typically be in fluid communication with one or more cooling assemblies formed particularly in the front plate 11, the rear plate 12 and any centre plate 14. Normally, a cooling fluid inlet 19 and a cooling fluid outlet 20 will be provided in the front plate and/or rear plate through which cooling fluid can enter the engine, and travel through the cooling assemblies in the casing plates to cool the engine.

[0063] In particular, a cooling assembly or configuration is preferably provided in relation to each casing plate, beneath the shaped recess 15 into which the replaceable wear plate 15 is located allowing cooling liquid to flow behind the replaceable wear plate 16 to cool the wear plate 16. This is best illustrated in Figures 6 and 7. A seal (not shown) is provided in a seal seating groove 23 to prevent the cooling liquid from access to the central opening 22 through the casing plate in which the output shaft rotates. A seal (not shown) is provided in a seal seating groove 24 to also prevent the cooling liquid from access to the intake/exhaust port 25.

[0064] According to the illustrated embodiment, each of the plates provided in the rotary engine of a preferred embodiment of the present invention includes a shaped recess 15 provided into the plate and into which the correspondingly shaped removable wear plate 16 is provided. The shaped recess 15 corresponds in size, shape and depth to the wear plate 16. In a preferred embodiment illustrated in Figures 6 and 7, the recess 15 has an arcuate upper and lower edge and a pair of opposed, substantially parallel side edges. As mentioned above, a bore opening 22 is provided through each of the plates for the output shaft. In a preferred embodiment, the recess 15 is approximately 6 mm in depth which corresponds to the preferred thickness of the wear plate 16 of 6 mm.

[0065] As mentioned above, the cooling assembly configuration is typically provided beneath the recess with the recess 15 being defined at its periphery by a number of peripheral edge portions 27 with a number of support wedges 26 being provided within the recess 15 in order to support the wear plate 16 in the recess. Each of the preferred support wedges 26 typically has a substantially coplanar outer or upper surface forming the base of the recess 15 to support the rear surface of the wear plate. The support wedges will typically be spaced from one another by channels 28 which extend beyond the periphery of the recess 15 as shown in Figure 6 in particular to allow cooling liquid to flow between the wedges 26 and access the rear surface of the wear plate 16 but also to flow around the edge of the wear plate 16. The cooling water is excluded from the portion of the wear surface on which the rotor rotates by a peripheral seal provided in a seal seating groove 29 is provided concentrically within the perimeter of the wear surface of the wear plate 16 to seat a perimeter seal (not shown) [0066] Preferably, a raised portion 30 is provided in one quadrant of the recess 15 in the casing plate and the intake/exhaust port 25 is provided through the raised portion 30. The raised portion 30 is shaped to correspond with a port pocket 31 formed in a rear surface 32 of each wear plate 16 as illustrated in Figure 9.

[0067] In the preferred embodiment illustrated, the raised portion 30 is at a different height to the support wedges 26 upon which a rear surface 32 of the wear plate 16 rests. In a preferred form, the port pocket 31 formed in a rear surface 32 of each wear plate 16 will preferably be approximately 2 mm in depth. A seal seating groove 24 is provided concentrically within the perimeter of the raised portion 30 and around the intake/outlet port 25 in order to prevent any of the cooling water accessing the intake/outlet port 25. A corresponding seal seating groove 35 is provided concentrically the intake/exhaust port opening 36 in the port pocket 31 on the wear plate 16 as well.

[0068] Preferably, a number of attachment openings 34 are provided about the central bore 22 on the casing plate in order to receive fasteners thereinto to attach the wear plate 16 at least temporarily relative to the recess 15 and corresponding openings 37 are provided in the wear plate 16.

[0069] An inlet/exhaust port 25 is typically provided as mentioned above in the raised portion 30 of the casing plate in fluid communication with an inlet and/or exhaust ports 38 provided through a side edge of the casing plate (configuration and position illustrated in Figure 2 and repeated in the casing plates of the preferred embodiment). Therefore, an inlet end/or exhaust port 38 provided through a side edge of the plate will normally communicate with a shaped channel through the casing plate in order to communicate with the inlet/exhaust port 25 provided in the raised portion 30 of the plate and further with a port opening 36 provided through the wear plate 16.

[0070] Each wear plate 16, and typically there will be more than one wear plate 16 provided in any single rotary engine, will normally have the same configuration, a preferred embodiment of which is illustrated in Figures 10 and 11. In particular, a pair of wear plates will normally be provided for each rotor provided in the rotary engine, one wear plate to abut each lateral side of the rotor during rotation. Typically, the rotors will rotate within the opening provided in the rotor plate directly abutting the wear plate on either lateral side.

[0071] The wear plates 16 will typically have higher wear resistant properties then the generally softer material used to form the plates of the rotary engine. One preferred material for use to form the wear plates is cast-iron or similar. The material used may be treated to increase/maximise the wear resistance of the wear plate.

[0072] Each wear plate 16 will typically be substantially planar, of consistent thickness across its dimension except for the preferred port pocket 31 provided in one quadrant. As mentioned, the preferred port pocket 31 will typically be approximately 2 mm in depth and the intake/outlet port 36 will typically be located within and preferably through the port pocket 31.

[0073] Each wear plate 16 will typically have two main surfaces substantially parallel with one another, one being the wear surface 33 which is oriented outwardly away from the casing plate relative to which the wear plate 16 is mounted and against which the rotor rotates and a rear surface 32 which is oriented toward the casing plate relative to which the wear plate 16 is mounted. The wear surface 33 will preferably be substantially planar and smooth.

[0074] A central opening 39 will typically be provided through the wear plate 16. The central opening 39 is generally circular with a number of attachment openings 37 provided around the periphery of the central opening 39 in order to receive the elongate fasteners to attach the wear plate 16 relative to the casing plate.

[0075] The wear plate 16 is shaped to correspond with the recess 15 in the casing plate relative to which it is to be attached. As illustrated, the wear plate 16 will have an arcuate top and bottom edge and a pair of substantially parallel, planar spaced apart side edges. As mentioned above, it is preferred that the wear plate 16 be approximately 6 mm in thickness.

[0076] Preferably, a peripheral groove 29 to seat a seal or gasket at least partially therein is provided concentrically within the outer perimeter of the wear plate into the surface of the wear surface side of the wear plate 16.

[0077] As illustrated in Figure 11 and discussed briefly above, a shaped recess is provided in one quadrant of the wear plate into the rear surface 32 in order to form a port pocket 31. Typically, the intake/outlet port 25 communicates with an intake/outlet opening 36 through the port pocket 31. Typically, the opening 36 is shaped to correspond with the intake/outlet port 25 in the raised portion 30 of the plate relative to which the port pocket 31 is located during attachment of the wear plate 16 relative to the plate.

[0078] The spacing between the opening in the port pocket and any groove or similar structure provided to seat a seal or gasket is important in maintaining sufficient material thickness therebetween to form an effective seal whilst not weakening the wear plate in the particular region.

[0079] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0080] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable maimer in one or more combinations.

[0081] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.

Claims (5)

1. A rotary engine with wear plate, the rotary engine including a number of casing plates including at least a front plate, a rear plate and at least one rotor housing plate having an opening in which a rotor rotates, at least one of the front plate or the rear plate includes a shaped recess and a correspondingly shaped removable wear plate provided in the shaped recess and against which the rotor rotates.

2. A rotary engine with wear plate as claimed in claim 1 including two or more rotor plates with at least one further casing plate namely at least one centre plate provided to separate the two or more rotor plates.

3. A rotary engine with wear plate as claimed in claim 2 wherein each centre plate is provided with a pair of shaped recesses, one on either side of the centre plate and a correspondingly shaped removable wear plate provided in each shaped recess and against which a rotor rotates.

4. A rotary engine with wear plate as claimed in any one of the preceding claims wherein the rotary engine is formed from a number of juxtapositioned casing plates which are fastened together to form an engine casing.

5. A replaceable wear plate for a rotary engine, the replaceable wear plate configured as a wide-waisted figure of 8 shape and manufactured of a wear resistant material, configured to be located relative to at least one of a front plate, a rear plate or a centre plate of a rotary engine.