Patent Grant
12104550
The present disclosure relates rotary engines in general and to rotary engine rotors in particular.
Combustion chambers of a rotary engine, such as a Wankel engine, are defined by a rotor and a housing. The housing includes a pair of side housings and a center housing that collectively define a rotor chamber that houses the rotor. Each side housing includes a side plate that provides a sealing surface for the rotor. The side plates are subject to high temperatures and pressure forces. What is needed is a rotary engine that includes side plates that can withstand the high temperature and pressure environment, and one that includes side plates that are an improvement over currently existing side plates.
According to an aspect of the present disclosure, a rotary internal combustion engine is provided that includes a housing and a rotor. The housing includes first and second side housings and a center housing. The center housing is disposed between and attached to the first and second side housings. The first and second side housings and the center housing define a rotor chamber. The rotor is disposed within the rotor chamber and is engaged with a rotor shaft that extends between the first and second side housings. The rotor has a peripheral side wall that extends between a pair of end face surfaces. At least one of the first side housing or the second side housing includes a side plate having a seal surface, an interior surface, and a core disposed between the seal surface and the interior surface. The core comprises a ceramic matrix composite (CMC) material. The seal surface of the side plate engages in a sealing arrangement with a respective rotor end face surface.
In any of the aspects or embodiments described above and herein, the seal surface of the side plate may consist of a ceramic material layer.
In any of the aspects or embodiments described above and herein, the interior surface of the side plate may consist of a ceramic material layer.
In any of the aspects or embodiments described above and herein, the side plate may include an outer edge surface that extends between the seal surface and the interior surface and extends around a periphery of the side plate.
In any of the aspects or embodiments described above and herein, the outer edge surface of the side plate may consist of a ceramic material layer.
In any of the aspects or embodiments described above and herein, the CMC material may include ceramic fibers disposed in a ceramic material matrix.
In any of the aspects or embodiments described above and herein, the fibers disposed in the ceramic material matrix may be in a two-dimensional arrangement.
In any of the aspects or embodiments described above and herein, the fibers disposed in the ceramic material matrix may be in a woven layer configuration.
In any of the aspects or embodiments described above and herein, the fibers disposed in the ceramic material matrix may be disposed in a plurality of woven layers.
In any of the aspects or embodiments described above and herein, the fibers disposed in the ceramic material matrix may be in a three-dimensional arrangement.
According to an aspect of the present disclosure, a side housing for a rotary internal combustion engine is provided that includes a perimeter section, a center section, and a side plate. The side plate is configured to be engaged with both the perimeter section and the center section. The side plate has a seal surface, an interior surface, and a core disposed between the seal surface and the interior surface, wherein the core comprises a ceramic matrix composite (CMC) material.
The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. For example, aspects and/or embodiments of the present disclosure may include any one or more of the individual features or elements disclosed above and/or below alone or in any combination thereof. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, the following description and drawings are intended to be exemplary in nature and non-limiting.
Referring to
The engine 20 includes three rotating combustion chambers 50-50B disposed between the rotor 24 and housing 22. The combustion chambers 50-50B are sealed by the rotor apex seals 46 and the end face seals 48 detailed above. The described sealing arrangement is provided to illustrate an example of a sealing arrangement and the present disclosure is not limited thereto.
The rotor 24 is journaled on an eccentric portion of the rotor shaft 26 such that rotation of the rotor shaft 26 causes the rotor 24 to orbitally revolve within the rotor chamber 36. The rotor shaft 26 may rotate three times for each complete orbital rotation of the rotor 24 within the rotor chamber 36. Oil seals (not shown) are provided relative to the eccentric portion of the rotor shaft 26 to impede leakage flow of lubricating oil radially outwardly thereof between the respective rotor end face surface 42 and the respective side housing side plate 34. During each rotation of the rotor 24, each combustion chamber 50-50B varies in volumes and moves around the rotor chamber 36 to undergo the four phases of intake, compression, expansion and exhaust, these phases being similar to the strokes in a reciprocating-type internal combustion engine having a four-stroke cycle.
The engine 20 includes a primary inlet port 52 in communication with a source of air, an exhaust port 54, and an optional purge port 56 also in communication with the source of air (e.g., a compressor) and located between the inlet and exhaust ports 52, 54. The ports 52, 54, 56 may be defined in a side housing 28, 30 or in the center housing 32. In the embodiment diagrammatically shown in
During operation of the engine 20, an acceptable fuel (e.g., conventional aviation fuels such as AVGAS or kerosene, or sustainable aviation fuels (SAFs), or the like) is delivered into the respective combustion chambers 50-50B through a fuel port (not shown) such that a respective combustion chamber 50-50B is stratified with a fuel-air mixture near an ignition source and a leaner mixture elsewhere, and the fuel-air mixture may be ignited within the combustion chamber 50-50B using any suitable ignition system known in the art (e.g. spark plug, glow plug). In a particular embodiment, the rotary engine 20 operates under the principle of the Miller or Atkinson cycle, with its compression ratio lower than its expansion ratio, through appropriate relative location of the primary inlet port 52 and exhaust port 54.
In the embodiment shown in
In some embodiments, the side plate 34 may be attached to the side housing 28, 30. In some embodiments, the side plate 34 may be in contact with the side housing 28, 30 but may be free to move a small amount relative to the side housing 28, 30; e.g., relative movement as a result of thermal expansion difference between the side plate 34 and the side housing 28, 30, or movement attributable to deflection, or the like. In the latter configuration, the side plate 34 may be described as “floating”. The present disclosure is not limited to any particular arrangement for securing a side plate 34 relative to a side housing 28, 30.
The present disclosure reflects a discovery by the inventors regarding a significantly improved side plate 34 configuration. Side plates comprising an aluminum material (e.g., various aluminum types, or aluminum alloy types, or the like) are known. Aluminum/Al alloys side plates are typically light weight and typically provide high thermal conductivity. However, aluminum/Al alloys side plates also typically have poor wear-resistance properties. In addition, aluminum/Al alloys typically have a high thermal coefficient of expansion and a low Young's modulus, which may result in undesirable deflection in a high temperature and pressure load environment.
U.S. Pat. No. 11,613,995, entitled “Rotary Engine with Housing having Silicon Carbide Plate”, which is hereby incorporated by reference in its entirety, discloses a side plate that comprises silicon carbide; e.g., the portion of the side plate that is in sealing engagement with the rotor end face seals is made of a ceramic material such as silicon carbide or aluminum nitride. The ceramic material possesses high thermal conductivity combined with low density, and also possesses a high degree of hardness that resists frictional wear. A side plate according to the '995 patent is understood to be a substantial improvement over known aluminum/Al alloy side plate configurations.
Aspects of the present disclosure are directed to a further significant side plate 34 improvement. Embodiments of the present disclosure include a side plate 34 comprising a ceramic matrix composite (CMC) core 86 with a ceramic material layer 88 disposed at only the seal surface 78 in some side plate 34 embodiments, and at both the seal surface 78 and the interior surface 80 at other side plate 34 embodiments; e.g., as shown in
The CMC core 86 may include one type of ceramic fiber material, or more than one type of ceramic fiber material. Non-limiting examples of ceramic fiber materials include silicon carbide (SiC), silicon oxycarbide (SiOC), alumina (Al2O3), and the like. The present disclosure is not limited to any particular ceramic fiber material. The CMC core matrix 86 may also comprise ceramic materials like SiC, SiOC, Al2O3, and the like. The present disclosure is not limited to any particular ceramic matrix material.
The ceramic material layer 88 disposed at the seal surface 78 or at both the seal surface 78 and the interior surface 80 (and/or on the outer edge surface 84) may comprise ceramic materials like SiC, SiOC, Al2O3, and the like. The present disclosure is not limited to any particular ceramic material layer material.
The CMC core 86 is understood to have improved resistance to crack propagation characteristics relative to a monolithic ceramic material; e.g., crack propagation is understood to be mitigated by the fibers within the CMC core 86 and fracture resistance is understood to be improved. Hence, the ceramic fiber reinforcements not only increase the CMC core's initial resistance to crack propagation but also the ceramic fiber reinforcements allow the CMC core 86 to avoid abrupt brittle failure that is often characteristic of monolithic ceramics.
The ceramic material layer 88 disposed at the seal surface 78 or at both the seal surface 78 and the interior surface 80 (and/or on the outer edge surface 84) does not include ceramic fiber reinforcement. The thickness of the ceramic material layer 88 on the seal surface 78 is chosen to be thick enough to withstand normal wear resulting from contact with the rotor seals (e.g., the end face seals 48) during operation of the engine 20 for the expected life of the rotor 24. In some applications, the thickness of the ceramic material layer 88 on the seal surface 78 may be in the range of 0.005-0.020 inches. The thickness of the ceramic material layer 88 on the interior surface 80 is chosen to be thick enough to withstand normal wear resulting from contact with the pedestal seat surfaces 72A, 72B and the side housing center section 62 (including features when present) that may occur during engine 20 operation. The thickness of the ceramic material layer 88 on the outer edge surface 84 is chosen to be thick enough to withstand normal wear resulting from contact with the pedestal surfaces 72A, 72B that may occur during engine 20 operation. The portion of the ceramic material layer seal surface 78 that is engaged with the rotor seals may be configured with a surface finish that improves sealing and seal durability.
While the principles of the disclosure have been described above in connection with specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the disclosure. Specific details are given in the above description to provide a thorough understanding of the embodiments. However, it is understood that the embodiments may be practiced without these specific details.
It is noted that the embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a block diagram, etc. Although any one of these structures may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc.
The singular forms “a,” “an,” and “the” refer to one or more than one, unless the context clearly dictates otherwise. For example, the term “comprising a specimen” includes single or plural specimens and is considered equivalent to the phrase “comprising at least one specimen.” The term “or” refers to a single element of stated alternative elements or a combination of two or more elements unless the context clearly indicates otherwise. As used herein, “comprises” means “includes.” Thus, “comprising A or B,” means “including A or B, or A and B,” without excluding additional elements.
It is noted that various connections are set forth between elements in the present description and drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. Any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.
No element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprise”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While various inventive aspects, concepts and features of the disclosures may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts, and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present application. Still further, while various alternative embodiments as to the various aspects, concepts, and features of the disclosures—such as alternative materials, structures, configurations, methods, devices, and components, and so on—may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts, or features into additional embodiments and uses within the scope of the present application even if such embodiments are not expressly disclosed herein. For example, in the exemplary embodiments described above within the Detailed Description portion of the present specification, elements may be described as individual units and shown as independent of one another to facilitate the description. In alternative embodiments, such elements may be configured as combined elements. It is further noted that various method or process steps for embodiments of the present disclosure are described herein. The description may present method and/or process steps as a particular sequence. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the description should not be construed as a limitation.
| Number | Name | Date | Kind |
|---|---|---|---|
| 6062188 | Okamura | May 2000 | A |
| 11613995 | Gagnon-Martin | Mar 2023 | B2 |
| 11761376 | Vinski | Sep 2023 | B1 |
| 20140230776 | Balendra | Aug 2014 | A1 |
| 20160160324 | Okun | Jun 2016 | A1 |
