Patent Application
20240301839
The present disclosure relates generally to rotary engine and more specifically to a seal system for a combustion chamber of a rotary engine.
A rotary engine is an internal combustion engine with one or more rotating pistons. The piston rotates within a combustion chamber defined within a housing that includes features for supplying coolant flow along with the required air/fuel mixture and lubricant. The combustion chamber is defined between two end walls that are exposed to high temperatures and pressures. The high temperatures and pressures can present challenges to operational longevity and performance.
Engine manufacturers continue to seek further improvements to engine performance including improvements to thermal, transfer and propulsive efficiencies.
A rotary internal combustion engine according to a disclosed example embodiment includes, among other possible things, a rotor housing having a peripheral wall circumscribing a rotor cavity, a rotor disposed within the rotor cavity, a side housing secured to the rotor housing, a plate defining a seal running surface for the rotor, the plate disposed between a portion of the side housing and the rotor housing, and at least one shim disposed between the plate and the side housing, the shim spacing the plate apart from contact with the side housing.
A rotary internal combustion engine according to another disclosed example embodiment includes, among other possible things, a rotor housing having a peripheral wall circumscribing a rotor cavity, a rotor disposed within the rotor cavity, a side housing secured to the rotor housing, a side plate disposed on an inner side of the side housing over the rotor cavity, the side plate defining a seal running surface for the rotor, and an outer shim disposed between the side plate and the side housing for spacing the side plate apart from contact with the side housing.
A method of assembling a rotary internal combustion engine according to another disclosed embodiment includes, among other possible things, placing an outer shim on a shoulder of a side housing, placing a side plate onto the outer shim such that the side plate is spaced apart from the shoulder of the side housing, and attaching the side housing to a rotor housing such that the side plate is disposed within a clearance space between a surface of the rotor housing and the outer shim.
Although the different examples have the specific components shown in the illustrations, embodiments of this invention are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples.
These and other features disclosed herein can be best understood from the following specification and drawings, the following of which is a brief description.
Referring to
The rotor 26 includes sides 34 that extend between three apex portions 32. An end seal 38 and apex seal 36 are disposed at each of the apex portions 32. The apex seal 36 provides for sealing against the peripheral wall 24 and the end seal 38 provides for sealing against a seal running surface 45 of a side plate 48 (
A corresponding one of the side plates 48 is held between a portion of the rotor housing 22 and the corresponding side housing 46. The side plates 48 are disposed within a clearance space between the rotor housing 22 and the side housing 46 in a manner such that the side plates 48 are not in contact with the side housing 46. The side plates 48 are spaced apart from the side housings 46 and are not clamped or otherwise in contact with the side housings 46.
Spacing the plates 48 away from the side housings 46 accommodates expansion during operation and prevents deterioration caused by contact. Accordingly, the side plates 48 may move within the space between the side housing 46 and the rotor housing 22. An outer shim 54 and an inner shim 56 are provided between the side plate 48 and the side housing 46 to space the side plate 48 from the side housing 46 and define a contact surface for the side plate 48.
Referring to
The outer shim 54 is supported on the shoulder 62 and extends across the channels 58. The side plate 48 is supported on the outer shim 54 such that no part of the sealing surface 45 of the side plate 58 is in direct contact with the side housing 46. The outer shim 54 provides an increased contact area for the side plate 48 to reduce localized contact pressures and stress concentrations and thereby localized wear.
Although the shoulder 62 is shown as being interrupted by the cooling channels 58, it is within the contemplation of this disclosure that the shoulder 62 may a continuous uninterrupted surface for the outer shim 54.
Referring to
The example side housing 46 may include other structures between the inner and outer shims 54, 56, such as for example, a flow directing structure 80. Such structures are disposed at height below that of a top of the shims 54, 56 to prevent contact with the side plate 48. Although a single structure 80 is shown by way of example, other structures may be in the space between the shims 54, 56 and also would be configured to prevent contact with the side plate 48.
In one example embodiment, the side plates 48 are formed from a silicon carbide material and the side housings are formed from aluminum. The silicon carbide material provides desirable tribological characteristics for operation with the rotor 26. The outer shim 54 provides an increased robustness to the interface between the dissimilar materials of the side housing 46 and the side plates 48. In one example embodiment, the shims 54, 56 are formed from a Cobalt-chromium alloy.
In one example embodiment, the shims 54, 56 includes a profile surface roughness (Ra) below 32 Ra. It should be appreciated, that although a range of profile surface roughness is disclosed by way of example, other surface roughness may be utilized and are within the contemplation and scope of this disclosure.
Although a specific material is disclosed by way of example, other materials with desirable wear properties could be utilized for each of the side plate 48 and the shims 54, 56 and are within the contemplation and scope of this disclosure. Moreover, a coating may be utilized on either of the shims 54, 56 and the side plate 48 to further reduce wear and is within the scope and contemplation of this disclosure. While the disclosed example shims 54, 56 are formed of the same material, the different shims 54, 56 may be formed from different materials to tailor use to specific locations. Additionally, although two shims are disclosed by way of example, various numbers of shims could be utilized within the scope and contemplation of this disclosure. Furthermore, the shape of the shims may be different from the example embodiment and remain within the contemplation and scope of this disclosure.
The inner and outer shims 54, 56 are shown as separate parts that are assembled to different locations. However, the inner and outer shims 54, 56 may be arranged as one single shim and remain within the contemplation and scope of this disclosure.
Referring to
The side plate 48 includes a thickness 104 that is less than the clearance space 102 such that the side plate 48 may move to compensate for differences in material thermal expansions during operation. In the example shown in
Referring to
Referring to
In one example embodiment, the outer shim 54 is supported on the shoulder 62. The shoulder 62 includes a width 92 that is less than a width 90 of the outer shim 54. In another example embodiment, the center seating surface 64 includes a width 96 that is less than a width 94 of the inner shim 56. The increased width of each of the inner and outer shims 54, 56, provide a desired surface area for supporting the side plate 48.
In one example embodiment, the width 92 of the outer shim 54 is such that the outer shim 54 overhangs the shoulder 62 by an overhang width 98. In one example embodiment, the overhang width 98 is between 0.5 and 3.0 times the thickness 88 of the outer shim 54. In another example embodiment, the width 98 is between 1.0 and 2.0 times the thickness 88 of the outer shim 54.
In another example embodiment, the width 94 of the inner shim 56 extends beyond the seating surface by an overhang width 100. In one example embodiment, the overhang width 100 is between 0.5 and 3 times the thickness 88 of the inner shim 56. In another example embodiment, the width 98 is between 1.0 and 2.0 times the thickness 88 of the outer shim 54. The inner shim 56 and the outer shim 54 may have different widths and thereby different proportions relative to the corresponding seating surface 64 and shoulder 62. The overhang widths 98, 100 reduce edge loading on the shims 4, 56 and the plate 48.
A rotary internal combustion engine 20 according to one example embodiments includes, among other possible things, a rotor housing 22 having a peripheral wall 24 circumscribing a rotor cavity 28, a rotor 26 disposed within the rotor cavity 28, a side housing 46 secured to the rotor housing 22, a plate 48 defining a seal running surface 45 for the rotor 26, the plate 48 disposed between a portion of the side housing 46 and the rotor housing 22, and at least one shim 54, 56 disposed between the plate 48 and the side housing 46, the shim spacing the plate 48 apart from contact with the side housing 46.
In a further embodiment of the forgoing rotary internal combustion engine 20, the plate 48 is disposed within a clearance space 102 between the at least one shim 54, 56 and the rotor housing 22.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the side housing 46 includes a sealing face 52 that seats against a housing face 50 of the rotor housing 22, an inner wall 60 transverse to the sealing face 52 and a shoulder 62 extending inward from the inner wall 60, wherein the at least one shim 54, 56 is seated on the shoulder 62.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the at least one shim 54, 56 is uninterrupted about the inner peripheral wall 24.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the shoulder 62 includes a width 92 and the at least one shim 54 includes a width 90 that is greater than the width of the shoulder 62.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the side housing 46 includes at least one coolant channel 58 interrupting the inner wall 60 and the shoulder 62, wherein the at least one shim 54, 56 extends over the at least one coolant channel 58.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the side housing 46 includes a center seating surface 64 spaced inward of the inner wall 60 and the at least one shim 54, 56 comprises an outer shim 54 seated on the shoulder 62 and an inner shim 56 seated on the center seating surface 64.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the center seating surface 64 includes a gap 78 and the inner shim 56 includes a first end 76 spaced apart across the gap 78 from a second end 76.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the at least one shim 54, 56 includes a surface roughness that is less than 32 Ra.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the side housing 46 includes at least one structure 80 between the shoulder 62 and the center seating surface 64, the at least one structure 80 spaced apart from the side plate 48.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the at least one shim 54, 56 is formed from a cobalt-chromium alloy.
A rotary internal combustion engine according to another example embodiment includes, among other possible things, a rotor housing 22 having a peripheral wall 24 circumscribing a rotor cavity 28, a rotor 26 disposed within the rotor cavity 28, a side housing 46 secured to the rotor housing 22, a side plate 48 disposed on an inner side of the side housing 46 over the rotor cavity 28, the side plate 48 defining a seal running surface for the rotor 26, and an outer shim disposed between the side plate 48 and the side housing 46 for spacing the side plate 48 apart from contact with the side housing 46.
In a further embodiment of the forgoing rotary internal combustion engines 20, the side housing 46 includes a center seating surface 64 with an inner shim 56 disposed between the center seating surface 64 and the side plate 48.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the side housing 46 includes a shoulder 62 extending inward from an inner wall 60 with the outer shim seated on the shoulder 62.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the side housing 46 includes a plurality of cooling channels 58 that extend inwardly through the shoulder 62 and the inner wall 60 and the outer shim 54 extends over each of the plurality of cooling channels 58.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the side housing 46 includes at least one structure 80 disposed between the inner wall 60 and the center seating surface 64, wherein the at least one structure 80 includes a top surface that is spaced apart from the side plate 48 when the side plate 48 is seated on the inner shim 56 and the outer shim 54.
In a further embodiment of any of the forgoing rotary internal combustion engines 20, the plurality of cooling channels 58 are disposed at varying intervals about the inner wall 60 of the side housing 46.
A method of assembling a rotary internal combustion engine according to another example embodiment includes, among other possible things, placing an outer shim on a shoulder 62 of a side housing 46, placing a side plate 48 onto the outer shim such that the side plate 48 is spaced apart from the shoulder 62 of the side housing 46, and attaching the side housing 46 to a rotor housing 22 such that the side plate 48 is disposed within a clearance space 102 between a surface of the rotor housing 22 and the outer shim 54.
In a further embodiment of the foregoing method, the side housing 46 includes a center seating surface 64 and assembly further includes placing an inner shim 56 on the center seating surface 64 and placing the side plate 48 includes placing the side plate 48 on the inner shim 56 and the outer shim 54.
In a further embodiment of any of the foregoing methods, placing the outer shim 54 further comprises placing the outer shim 54 across at least one coolant channel 58.
Accordingly, the disclosed shims prevent and/or reduce wear on side plates of a rotary engine to improve operational longevity.
Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the scope and content of this disclosure.
