Engine displacer with heat accumulator passage

Abstract

A displacer for an engine includes a body extending along a displacer longitudinal axis from a displacer first end face to a displacer second end face. At least one channel extends between a first opening in the displacer first end face and a second opening in the displacer second end face and has a sidewall between the first opening in the displacer first end face and the second opening in the displacer second end face, the sidewall defining a channel flow path. The first opening is located in a first radial direction at a first radial distance from the displacer longitudinal axis and the second opening is located in a second radial direction at a second radial distance from the displacer longitudinal axis. At least a portion of the channel flow path has a component in an angular direction that is angled to both the first radial direction and the second radial direction.

Description

Technical Field

[0001] Various embodiments described herein generally relate to thermodynamic engine components. More specifically, various embodiments relate to a displacer for an engine with a regenerator channel. Background Art

[0002] Stirling engine (Stirling engine) converts heat energy into mechanical work.Some Stirling engines include a piston, which is contained in a piston chamber and connected to the main engine shaft. The piston is responsible for the power of the engine. Some Stirling engines (for example, gamma Stirling engine and beta Stirling engine) also include a displacer, which is contained in a displacer chamber and connected to the main engine shaft. The displacer moves a working fluid between the hot side and the cold side of the displacer chamber, and the working fluid will expand or compress in the displacer chamber. The pressure changes caused in the displacer chamber due to temperature changes and the expansion or compression of the working fluid result in net work output.

[0003] A key aspect of an efficient Stirling engine is the ability to transfer heat to and from the working fluid, as this affects the expansion and compression of the working fluid and ultimately the performance of the engine. Therefore, there is a need for a displacer and displacer chamber with improved heat transfer capabilities. Summary of the Invention

[0004] According to one main aspect of the teachings herein, in at least one embodiment described herein, a displacer for an engine is provided. The displacer includes a body extending along a displacer longitudinal axis from a first displacer end face to a second displacer end face, and at least one channel extending between a first opening in the displacer first end face and a second opening in the displacer second end face, and having a sidewall between the first opening in the displacer first end face and the second opening in the displacer second end face, the sidewall defining a channel flow path. The first opening is located at a first radial distance from the displacer longitudinal axis in a first radial direction, and the second opening is located at a second radial distance from the displacer longitudinal axis in a second radial direction. At least a portion of the channel flow path has a component in an angular direction that is angled with the first radial direction and the second radial direction.

[0005] In at least one embodiment, the component extends throughout the channel flow path.

[0006] In at least one embodiment, a portion of the channel flow path is parallel to the displacer longitudinal axis.

[0007] In at least one embodiment, the body includes at least three channels.

[0008] In at least one embodiment, each of the at least one channel has a circular cross-section.

[0009] In at least one embodiment, the cross-section of at least one of the at least one channel is constant along the channel flow path.

[0010] In at least one embodiment, the cross-section of at least one of the at least one channel varies along the channel flow path.

[0011] In at least one embodiment, a cross-section of at least one of the at least one channel narrows toward the displacer first end face and the displacer second end face.

[0012] In at least one embodiment, the displacer further includes a displacer shaft extending from the displacer first end face along the displacer longitudinal axis.

[0013] In at least one embodiment, the first radial distance and the second radial distance are different.

[0014] In at least one embodiment, the displacer further comprises a heat accumulator contained within each of the at least one channel.

[0015] In at least one embodiment, the heat accumulator forms part of a side wall of at least one channel.

[0016] In at least one embodiment, the thermal accumulator is contained within a side wall of at least one channel.

[0017] In at least one embodiment, the body is solid and the aperture in the body provides a sidewall for the at least one channel.

[0018] In at least one embodiment, the engine is at least one of a Stirling engine and an Ericsson engine.

[0019] According to one broad aspect of the teachings herein, in at least one embodiment described herein, an engine assembly is provided. The engine assembly includes a displacer. The displacer includes a body having a first displacer end face, a second displacer end face, and a displacer longitudinal axis; and at least one channel extending between a first opening in the displacer first end face and a second opening in the displacer second end face, and having a sidewall between the first opening in the displacer first end face and the second opening in the displacer second end face, the sidewall defining a channel flow path. The first opening is located at a first radial distance from the displacer longitudinal axis in a first radial direction, and the second opening is located at a second radial distance from the displacer longitudinal axis in a second radial direction. At least a portion of the channel flow path has a component in an angular direction that is angled to both the first radial direction and the second radial direction. The engine assembly also includes a displacer chamber forming an internal cavity, wherein, in an assembled position, the displacer body is housed within the internal cavity.

[0020] In at least one embodiment, the component extends throughout the channel flow path.

[0021] In at least one embodiment, a portion of the channel flow path is parallel to the displacer longitudinal axis.

[0022] In at least one embodiment, the body includes at least three channels.

[0023] According to one major aspect of the teachings herein, in at least one embodiment described herein, a displacer for moving a working fluid within a displacer chamber is provided. The displacer includes a body having a first displacer end face at one end, a second displacer end face at the other end, and a displacer longitudinal axis; and at least one channel extending between the first displacer end face and the second displacer end face. The at least one channel defines a channel flow path for the working fluid through the displacer. The at least one channel is angled in an azimuth direction to force the working fluid to swirl upon exiting the channel.

[0024] Other features and advantages of the present application will become apparent from the following detailed description in conjunction with the accompanying drawings. However, it should be understood that although the detailed description and specific examples indicate preferred embodiments of the present application, they are given by way of example only, as those skilled in the art will clearly understand various changes and modifications within the spirit and scope of the present application from this detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For a better understanding of the various embodiments described herein, and to more clearly show how these various embodiments may be put into practice, reference will now be made to the accompanying drawings, which illustrate at least one exemplary embodiment, which will now be described. The drawings are not intended to limit the scope of the teachings described herein.

[0026] Figure 1 is a cutaway perspective view of a displacer according to an example embodiment;

[0027] Figure 2 yes Figure 1 Top view of the displacer;

[0028] Figure 3 It is placed in the displacer chamber Figure 1 A cross-sectional side view of a displacer;

[0029] Figure 4 is a cross-sectional perspective view of an example displacer and displacer chamber according to another example embodiment;

[0030] Figure 5 yes Figure 4 a schematic cross-sectional perspective view of a portion of a displacer;

[0031] Figure 6 yes Figure 4 A top perspective view of a displacer;

[0032] Figure 7 The working fluid flows through Figure 4 Schematic diagram of the displacer;

[0033] Figure 8 is a cross-sectional perspective view of an example displacer and displacer chamber according to another example embodiment;

[0034] Figure 9 yes Figure 8 A top perspective view of a displacer;

[0035] Figure 10 is a side view of a displacer and displacer chamber according to another example embodiment;

[0036] Figure 11 yes Figure 10 a cutaway perspective view of a displacer and a displacer chamber;

[0037] Figure 12 is a schematic cross-sectional perspective view of a displacer according to another example embodiment; and

[0038] Figure 13 It is the process flow of the operation of the displacer within the displacer chamber.

[0039] Other aspects and features of the example embodiments described herein will become apparent from the following description taken in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0040] Various embodiments according to the teachings herein will be described below to provide examples of at least one embodiment of the claimed subject matter. Any embodiment described herein does not limit any claimed subject matter. The claimed subject matter is not limited to an apparatus or method having all the features of any one apparatus or method described below, or to features common to multiple or all apparatuses and / or methods described herein. The apparatus or method described herein may not be an embodiment of any claimed subject matter. Any subject matter described herein that is not claimed in this document may be the subject of another protective instrument, for example, a continuing patent application, and the applicant, inventor, or owner has no intention of abandoning any such subject matter of the disclosure, waiving any such subject matter of the disclosure, or contributing any such subject matter of the disclosure to the public by disclosure in this document.

[0041] It should be understood that for simplicity and clarity of explanation, reference numerals may be repeated in the figures to indicate corresponding or similar elements or steps, where appropriate. In addition, many specific details are described to provide a thorough understanding of the embodiments described herein. However, one of ordinary skill in the art will appreciate that the embodiments described herein can be implemented without these specific details. In other cases, well-known methods, procedures, and components are not described in detail to avoid blurring the embodiments described herein. In addition, this description should not be considered to limit the scope of the embodiments described herein.

[0042] It should also be noted that the terms "coupled" or "coupled" as used herein can have several different meanings, depending on the context in which they are used. For example, the terms coupled or coupled can have mechanical, fluidic, or electrical meanings. For example, the terms coupled or coupled as used herein can mean that two elements or devices can be connected to each other directly or through one or more intermediate elements or devices via electrical signals, electrical connections, mechanical elements, fluids, or fluid transfer paths, for example, depending on the specific context.

[0043] It should also be noted that the term "and / or" as used herein is intended to mean an inclusive or. That is, "X and / or Y" is intended to mean X or Y or both. As a further example, "X, Y and / or Z" is intended to mean X or Y or Z or any combination thereof. As another example, the phrase "A, B, C or any operable combination thereof" or "any combination of A, B, and C" is intended to encompass any combination of elements A, B, and C that provides utility, e.g., A, B, C, A and B, A and C, B and C, or A, B, and C.

[0044] It should be noted that terms of degree used herein, such as "substantially," "about," and "approximately," refer to a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree can also be construed as including deviations of the modified term, such as, but not limited to, 1%, 2%, 5%, or 10%, as long as such deviations do not negate the meaning of the modified term.

[0045] In addition, numerical ranges recited herein by endpoints include all numbers and fractions within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, and 5). It should also be understood that all numbers and fractions thereof are modified by the term "about," meaning that the recited number may vary by at most a certain amount, such as, but not limited to, 1%, 2%, 5%, or 10%, without significantly changing the end result.

[0046] Some components herein may be identified by a part number consisting of a base number followed by an alphabetical or subscript numeric suffix (e.g., 112a or 1121). Multiple components herein may be identified by part numbers that share a base number and differ in their suffixes (e.g., 1121, 1122, and 1123). All components having a common base number may be collectively or generically referred to using the base number without a suffix (e.g., 112).

[0047] Now refer to Figure 1 , which shows a displacer 100. The displacer 100 has a body 104. The body 104 extends along a displacer longitudinal axis 108 from a displacer first end face 112a to a displacer second end face 112b. Figure 1 The displacer first end face 112a is shown as being vertically above and spaced apart from the displacer second end face 112b. It should be understood that because the function of the displacer 100 does not rely on the use of gravity, the displacer 100 can be oriented in any suitable orientation (e.g., the displacer first end face 112a is below the displacer second end face 112b, the displacer first end face 112a and the displacer second end face 112b are angled relative to the horizontal, etc.).

[0048] The body 104 can be of any suitable shape. In the exemplary embodiment shown herein, the body 104 is cylindrical with the displacer longitudinal axis 108 extending in an axial direction (e.g., in the longitudinal direction of the displacer). The body 104 has a displacer axial length 109 and a displacer diameter 111 (e.g., see FIG. Figure 2) or displacer circumference. As shown, the body 104 has a barrel portion 110, and the displacer first end surface 112a and the displacer second end surface 112b form the ends (i.e., end caps or heads) of the barrel portion 110, which in this embodiment are rounded and planar (i.e., flat). In other embodiments, the first and second end surfaces 112 may not be flat, but may have other forms (e.g., dome-shaped). In some embodiments, for example, Figure 1 In other embodiments, for example, the body 104 is generally hollow. Figure 4 and Figure 8 In the embodiment, the body 104 is generally solid.

[0049] review Figure 1 , the displacer first end face and the displacer second end face 112 extend in a radial direction about the displacer axis. In other words, the displacer first end face and the displacer second end face 112 extend outward from the center point of the displacer first and second end faces 112. In some embodiments, for example, Figure 1 In the embodiment, the main body 104 may further include lips 116a and 116b for connecting the displacer first end surface 112a and the displacer second end surface 112b to the barrel 110, respectively.

[0050] In some embodiments, the displacer second end face 112b and lip 116b are made of steel, while the barrel 110, displacer first end face 112a, and lip 116a are made of aluminum. Aluminum can be used because it is a relatively lightweight material compared to steel. However, steel may be preferred on portions of the displacer that are exposed to more heat because steel can withstand higher temperatures and expand less when exposed to heat than aluminum. In some embodiments, portions of the displacer 100 may be made of stainless steel, titanium, or any other suitable material.

[0051] The displacer 100 also includes a displacer shaft 118. The displacer shaft 118 extends from the displacer first end face 112a along the displacer longitudinal axis 108. The displacer shaft 118 connects the displacer 100 to a main engine shaft (not shown).

[0052] The displacer 100 has at least one channel 120. In some embodiments, the displacer 100 has three channels 120 ( Figure 1 ), five channels ( Figure 4-7 and Figure 10-12 ) or eight channels ( Figure 8-9). The number of channels 120 may depend on the desired thermal mass ratio of the heat accumulator 136 (described below) to the working fluid, the heat accumulator grid density, the dead volume, and space constraints. The channels 120 extend between the displacer first end face 112a and the displacer second end face 112b. Specifically, each channel 120 extends between a first channel opening 121a in the displacer first end face 112a and a second channel opening 121b in the displacer second end face 112b. In embodiments where the body 104 is substantially hollow, as shown Figure 1 As shown, sidewalls 122 define each channel 120. In embodiments where the body 104 is substantially solid, as shown in FIG. Figure 4 As shown, a hole is formed in the solid cylindrical portion 110 to define each passage 120 .

[0053] The sidewalls of the channel 120 define a channel flow path 124 (i.e., a flow path of the working fluid through the channel 120). Under different operating conditions, the working fluid can flow through the channel 120 in either direction (i.e., from the displacer first end face 112a toward the displacer second end face 112b, or from the displacer second end face 112b toward the displacer first end face 112a), as further described below.

[0054] See also Figure 2 , each first channel opening 121a is located at a first radial distance 126a relative to the center point of the displacer first end face 112a. Similarly, each second channel opening 121b is located at a second radial distance 126b relative to the center point of the displacer second end face 112b. The first radial distance 126a and the second radial distance 126b can be any suitable distance greater than zero (i.e., the centers of the first channel opening 121a and the second channel opening 121b are not located at the center points of the displacer first end face 112a and the displacer second end face 112b). If the displacer 100 includes more than one channel 120, such as Figure 2 As shown, the radial distance 126a from the center point to each first passage opening 121a may be the same first radial distance or different first radial distances. Figure 2 The first channel openings 121a are shown to be at the same first radial distance 126a. Similarly, the second radial distance 126b from the center point to each second channel opening 121b can be the same second radial distance or a different second radial distance. In some embodiments, for example, Figure 1 In some embodiments, the first radial distance 126a is approximately equal to the second radial distance 126b. In other embodiments, the first radial distance 126a can be greater than or less than the second radial distance 126b.

[0055] The channel 120 may have different cross-sections in different embodiments. Figure 2As shown, each channel 120 has a circular cross-section with a diameter of 128. In other embodiments, the cross-section can be elliptical or have other shapes. Specifically, the cross-section can be elliptical with the major axis in the radial direction and the minor axis in the angular / azimuthal direction (further described below). In some embodiments, for example, Figure 1 In the embodiment shown in FIG. 1 , the cross-section of the channel 120 remains constant along the entire channel 120 (i.e., the diameter 128 remains constant along the entire channel path 124). In other embodiments, the cross-section may not remain constant along the entire channel 120. For example, Figure 10-12 As shown, the diameter 128 may decrease toward each of the displacer first and second end faces 112. The decrease in diameter 128 will result in an increase in the velocity of the fluid exiting the passage 120, which ultimately results in more heat transfer, as further described below.

[0056] In the embodiments described herein, at least a portion of the channel 120 is angled relative to the radial direction. Specifically, at least a portion of the channel 120 (and therefore also a portion of the channel flow path 124) has a component (i.e., a segment) in an azimuthal (i.e., angular) direction (i.e., in a generally azimuthal direction 132) that is generally angled relative to the radial direction. In other words, the channel 120 has at least one portion that has a component (i.e., a segment) in a direction that is generally angled relative to the radial direction at an angle 133. Figure 2 ). Angle 133 is the angle between the first radial distance 126a and the approximate azimuthal direction 132. For example, Figure 2 A first opening 121a is shown, wherein the channel 120 at the opening 121a will extend in a generally azimuthal direction 132. The generally azimuthal direction 132 may not be completely azimuthal (at a ninety-degree angle) to the radial direction. As referred to herein, "generally azimuthal" to the radial direction means that the angle 133 is non-zero.

[0057] In particular, the portion of the channel 120 near the channel opening 121 may have a component in a generally azimuthal direction. Angling the channel 120 near the channel opening 121 may cause the working fluid exiting the channel opening 121 to generate a vortex, as described below. Angling the channel 120 near the channel opening 121 may also cause the working fluid to generate a more intense vortex when exiting the channel opening 121 (see, for example, Figure 10-12 ).

[0058] In some embodiments, for example, Figure 4 and Figure 8 In other embodiments, for example, the entire channel flow path 124 has a substantially azimuthal component (i.e., the entire channel 120 has a substantially azimuthal component). Figure 1In , only the portion of the channel flow path 124 has a substantially azimuthal component. Figure 1 For example, the portion 140 of the channel flow path 124 is only in the axial direction (in Figure 1 The vertical direction is shown in the figure.

[0059] In some embodiments, a heat accumulator 136 is included within each channel 120. In other embodiments, the walls of the channels 120 (e.g., sidewalls 122) can serve as the heat accumulator. The heat accumulator 136 can be any material that stores heat, typically a porous material such as steel mesh, steel wool, or any metal (e.g., copper) fiber material. Figure 1 In the embodiment shown, the heat accumulator 136 comprises a plurality of mesh disks. In other embodiments, the heat accumulator 136 may have other configurations, such as a spiral or annular configuration. If the heat accumulator 136 is annular, the heat accumulator 136 may form at least a portion of the sidewall 122. The heat accumulator 136 may be positioned along approximately one-fifth, approximately one-quarter, or more of the channel flow path 124. The ratio of the length of the heat accumulator to the length of the channel flow path 124 may be determined based on the thermodynamic design of the displacer. In some embodiments, for example, Figure 1 In the embodiment, the heat accumulator 136 is contained within the portion 140. In other embodiments, for example in Figure 4 and Figure 8 In the embodiment shown, the thermal accumulator 136 is contained within the central portion of the channel flow path 124 (i.e., the thermal accumulator 136 is generally located in the center of the channel flow path 124). In other embodiments, the thermal accumulator 136 may not be located in the center of the channel flow path 124. The thermal accumulator 136 may be thermally insulated with an insulating material 144 ( Figure 1 ). For example, the insulating material 144 can be a ceramic bushing.

[0060] Now refer to Figure 3 , Figure 3 The displacer 100 is shown positioned within a displacer chamber 200. The displacer chamber 200 has a first chamber face 204a and a second displacer face 204b. The first chamber face 204a is spaced apart from the second chamber face 204b along a chamber axis 208. When the displacer 100 is positioned within the displacer chamber 200, the displacer longitudinal axis 108 and the chamber axis 208 are coaxial. The displacer chamber 200 further has a chamber barrel 210. The chamber barrel 210, along with the first chamber face 204a and the second chamber face 204b, form an interior cavity 212. The interior cavity 212 has a cavity length 214 and a cavity diameter 215.

[0061] The displacer chamber 200 has an aperture 216 in the chamber first face 204a. When the displacer 100 is located within the displacer chamber 200, the shaft 118 passes through the aperture 216. Figure 11 shown.

[0062] When the displacer 100 is located within the displacer chamber 200, the body 104 is mounted within the internal cavity 212. The cavity length 214 is greater than the displacer axial length 109, allowing the displacer 100 to move axially within the internal cavity 212. The cavity diameter 215 is slightly greater than the displacer diameter 111, allowing the displacer 100 to slide tightly with the chamber barrel 210 and not move radially within the displacer chamber 200. In some embodiments, a wear ring 144 (e.g., see FIG. 144 ) may be used. Figure 1 ) or a seal seals the displacer 100 to the chamber barrel 210.

[0063] In operation, an external heat source (not shown) is positioned proximate to the chamber second side 204b, and an external heat sink (not shown) is positioned proximate to the chamber first side 204a. Thus, the end of the displacer chamber 200 containing the chamber second side 204b can be referred to as the "hot end," containing the "hot side," while the end of the displacer chamber 200 containing the chamber first side 204a can be referred to as the "cold end," containing the "cold side."

[0064] Now refer to Figure 13 , which is a flow chart illustrating an example embodiment of a method 300 for operating a displacer within a displacer chamber. For example, the method 300 may be used to operate the displacer 100 within the displacer chamber 200. For ease of illustration, reference is made to Figure 1-3 , but method 300 may be applied to any other embodiment described herein.

[0065] Method 300 may begin at step 304. In step 304, a displacer (e.g., displacer 100) is positioned at the cold end of the internal cavity (e.g., near the first chamber face 204a in the internal cavity 212) and paused. The internal cavity 212 also contains a working fluid, such as air. When the displacer 100 is positioned at the cold end of the internal cavity 212, a majority of the working fluid is positioned at the hot end (e.g., near the second chamber face 204b) and is heated by an external heat source.

[0066] In step 308, the displacer 100 begins to rapidly move within the internal cavity 212 toward the hot end. This movement is caused by movement of the displacer shaft 118. The displacer shaft 118 moves linearly due to its connection to the main engine shaft. The displacer shaft 118 may be connected to the main engine shaft via a crankshaft, a grooved cam, or other device that generates linear motion based on the rotation of the main engine shaft.

[0067] At step 312, as the displacer 100 moves toward the hot end, the hot working fluid is forced into the channels (e.g., channels 120) of the displacer 100. The hot working fluid moves rapidly through the channels 120 (e.g., along the channel flow paths 124) and through at least one of the heat accumulators within the channels (e.g., the heat accumulator 136 or the sidewalls 122 that act as heat accumulators, as described above). As the hot working fluid moves over the heat accumulators, the heat accumulators absorb and store some of the heat from the working fluid. As previously described, the displacer 100 is a tight sliding fit with the chamber barrel 210. Due to this design, most of the working fluid moves through the channels 120 rather than between the displacer 100 and the chamber barrel 210.

[0068] At step 316, the hot working fluid exits the channels 120. Because the channels 120 have components (ie, segments) in a generally azimuthal direction, the exiting fluid swirls along the cold face (eg, first face 204a) of the interior cavity. Figure 7 is a schematic diagram of the vortex of the working fluid as it leaves the channel 120. When the hot working fluid swirls on the cold surface, heat is transferred from the hot working fluid to the heat sink. Swirling the working fluid along the cavity surface is beneficial because the working fluid can flow quickly along the surface. Since convective heat transfer is related to fluid velocity, it can transfer more heat. Swirling fluid is also more efficient than fluid that directly hits the cold surface. For example, if the channel 120 has no azimuthal component, then for each channel 120, the fluid will leave the channel 120 and directly hit the end surface of the internal cavity (e.g., the first surface 204a). The fluid will then be ejected in various directions at multiple points on the end surface, colliding with each other and minimizing heat transfer. By angling the ends of the channel 120 in the azimuthal direction, all the working fluid leaving the channel swirls together, thereby increasing heat transfer. Having two or more channels 120 helps keep the fluid swirls balanced within the internal cavity 212.

[0069] review Figure 13 , at step 320, the displacer continues to move toward the hot end of the chamber.

[0070] At step 324, the working fluid continues to exit the opening of the channel 120. The exiting hot fluid causes the fluid swirling along the cold surface of the internal cavity 212 (e.g., the first chamber face 204a) (i.e., the cooling fluid) to move away from the cold surface and return to the displacer 100 (i.e., back to the displacer first end face 112a). In doing so, the exiting hot fluid can then swirl along the cold surface of the cavity. In other words, as the hot fluid exits the channel 120, a swirling fluid layer is formed on the cold side of the chamber 200.

[0071] At step 328, the displacer 100 reaches the vicinity of the chamber hot end of the displacer chamber 200 and pauses. During this pause, the swirling fluid can continue to swirl and transfer heat.

[0072] At step 332 , movement of the displacer shaft 118 causes the displacer to begin moving back toward the cold end of the displacer chamber 200 (eg, toward the chamber first face 204 a ).

[0073] At step 336, as the displacer 100 moves toward the cold end of the displacer chamber 200, the cold working fluid is forced into the displacer's channels 120. The cold working fluid moves rapidly through the channels 120 and passes through the thermal accumulators 136 within each channel 120. As the cold working fluid moves over the thermal accumulators 136, the thermal accumulators 136 release stored heat back into the cold working fluid.

[0074] At step 340, the cold working fluid exits the channel 120. Because the exit portion of the channel 120 adjacent to the opening of the channel 120 has a component in the azimuthal direction, the exiting fluid swirls along the hot surface (e.g., the chamber second surface 204b) of the interior cavity 212. As the cold working fluid swirls on the hot surface, heat is transferred from the heat source to the cold working fluid.

[0075] At step 344 , the displacer 100 continues to move toward the cold end of the displacer chamber 200 .

[0076] At step 348, the working fluid continues to exit the channel 120. The exiting cold fluid removes the fluid (i.e., the fluid being heated) swirling along the hot side of the chamber (e.g., the chamber second side 204b) from the surface and returns to the displacer 100 (i.e., back to the displacer second end face 112b). In this way, the exiting cold fluid can then swirl along the hot side of the chamber. Similar to step 324, as the cold fluid exits the channel, a swirling fluid layer is formed on the hot side of the chamber.

[0077] The method 300 then returns to step 304. Since the method 300 is cyclical, the method may begin at a step other than step 304 (eg, step 328).

[0078] It should be understood that while the displacer 100 may be used as part of a Stirling engine, the displacer 100 may also be used with other types of engines, such as, but not limited to, an Ericsson engine.

[0079] Although the applicant's teachings described herein are combined with various embodiments for illustrative purposes, the applicant's teachings are not limited to these embodiments. On the contrary, the applicant's teachings described and shown herein encompass various alternatives, modifications, and equivalents, without generally departing from the embodiments described herein. For example, although the teachings described and shown herein may include certain elements / components and steps, modifications known to those skilled in the art may be made. For example, selected features in one or more example embodiments described herein may be combined to create alternative embodiments that are not explicitly described, according to the teachings herein. All values ​​and subranges within the disclosed range are also disclosed. The subject matter described herein is intended to encompass and include all appropriate changes in technology.

Claims

1. A displacer for an engine, the displacer comprising: a body extending along the displacer longitudinal axis from a displacer first end face to a displacer second end face; at least one channel extending between a first opening in a first end face of the displacer and a second opening in a second end face of the displacer and having a sidewall therebetween, the sidewall defining a channel flow path, wherein the first opening is located at a first radial distance from a longitudinal axis of the displacer in a first radial direction and the second opening is located at a second radial distance from the longitudinal axis of the displacer in a second radial direction; and Wherein at least part of the channel flow path has a component in an angular direction which is at an angle to both the first radial direction and the second radial direction.

2. The displacer according to claim 1, wherein The component extends throughout the channel flow path.

3. The displacer according to claim 1, wherein: Portions of the channel flow path are parallel to the displacer longitudinal axis.

4. The displacer according to claim 1, wherein: The body includes at least three channels.

5. The displacer according to claim 1, wherein: Each of the at least one channel has a circular cross-section.

6. The displacer according to claim 1, wherein: The cross-section of at least one of the at least one channel is constant along the channel flow path.

7. The displacer according to claim 1, wherein: The cross-section of at least one of the at least one channel varies along the channel flow path.

8. The displacer according to claim 7, wherein: A cross-section of at least one of the at least one channel narrows toward the displacer first end face and the displacer second end face.

9. The displacer of claim 1, further comprising a displacer shaft extending from the displacer first end face along the displacer longitudinal axis.

10. The displacer according to claim 1, wherein The first radial distance and the second radial distance are different.

11. The displacer of claim 1 , further comprising a heat accumulator contained within each of the at least one channel.

12. The displacer according to claim 11, wherein The heat accumulator forms part of the side wall of the at least one channel.

13. The displacer according to claim 11, wherein The heat accumulator is contained within the side wall of the at least one channel.

14. The displacer according to claim 1, wherein The body is solid and an aperture in the body provides the sidewalls for the at least one channel.

15. The displacer according to claim 1, wherein The engine is at least one of a Stirling engine and an Ericsson engine.

16. An engine assembly, comprising: A displacer, comprising: a body having a displacer first end face, a displacer second end face, and a displacer longitudinal axis; and at least one channel extending between a first opening in a first end face of the displacer and a second opening in a second end face of the displacer and having a sidewall therebetween, the sidewall defining a channel flow path, wherein the first opening is located at a first radial distance from a longitudinal axis of the displacer in a first radial direction and the second opening is located at a second radial distance from the longitudinal axis of the displacer in a second radial direction; wherein at least a portion of the channel flow path has a component of an angular direction that is at an angle to both the first radial direction and the second radial direction; and a displacer chamber, said displacer chamber forming an interior cavity, Wherein, in the assembled position, the body of the displacer is housed within the internal cavity.

17. The engine assembly of claim 16, wherein: The component extends throughout the channel flow path.

18. The engine assembly of claim 16, wherein: Portions of the channel flow path are parallel to the displacer longitudinal axis.

19. The engine assembly of claim 17, wherein: The body includes at least three channels.

20. A displacer for moving a working fluid in a displacer chamber, the displacer comprising: a main body having a displacer first end surface at one end and a displacer second end surface at the other end, and having a displacer longitudinal axis; as well as At least one channel extends between the displacer first end face and the displacer second end face, the at least one channel defining a channel flow path for the working fluid through the displacer, and wherein the at least one channel is angled in an azimuth direction to force the working fluid to swirl upon exiting the channel.

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