JP2014066218A - Stirling cycle engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Stirling cycle engine that can be used under high temperature while keeping heat insulation between a high temperature part and a low temperature part.SOLUTION: A displacer 70 and an upper cylinder 10 housing it are made of a ceramic material. Thereby, compared to a conventional Stirling cycle engine in which a displacer and a cylinder are made of a resin material, a Stirling cycle engine of the present invention can be continuously operated under high temperature. Also, compared to a conventional Stirling cycle engine in which a displacer and a cylinder are formed of metal with high heat conductivity such as stainless, a performance for shielding heat of a high-temperature expansion chamber and a low-temperature compression chamber is high, and therefore, efficiency of power generation can be improved.

Description

  The present invention relates to a Stirling cycle engine that performs power generation, cooling, and the like using a Stirling cycle.

  A Stirling cycle engine having a structure in which a displacer and a piston are coaxially arranged in a cylinder has been widely known, and has been put into practical use as a generator or a refrigerator. Generally, in this type of Stirling cycle engine, a permanent magnet is attached to a piston, and a stator and a yoke are arranged with the permanent magnet interposed therebetween. In the case of a generator, the working gas is repeatedly compressed and expanded by a temperature difference given from the outside, so that the piston reciprocates, and the kinetic energy is converted into electric energy by the electromagnetic action between the permanent magnet and the stator. On the other hand, in the case of a refrigerator, the piston reciprocates by passing a driving current through the electromagnetic coil of the stator, and the working gas repeats compression and expansion along with the reciprocation, thereby causing a temperature difference between the low temperature part and the high temperature part. Occurs.

  In the solar thermal power generation device, the temperature of the high temperature part may be, for example, 800 ° C. or higher by focusing the sunlight. When applying a Stirling cycle engine to such a power generator, the heat resistance performance of the displacer and the cylinder located on the high temperature side becomes a problem.

In general, displacers and the cylinders that house them include PPS (Poly
A resin material such as Phenylene Sulfide) is used. The use limit temperature of the resin material is approximately 300 ° C. or less even if it has excellent heat resistance, and the resin material cannot be used in an apparatus that operates continuously at a high temperature of 800 ° C.

  In order to further improve the heat resistance, it is also conceivable to use a metal material such as stainless steel. However, when a metal material is used for a sprayer or the like, the thermal conductivity is increased, so that the heat insulation performance between the high temperature portion and the low temperature portion is lowered, thereby causing a problem that the power generation efficiency is lowered. In addition, when a metal material is used, there is a problem that the weight becomes heavier than that of the resin, and there is a problem that the number of parts increases and the cost increases.

  This invention is made | formed in view of this situation, The objective is to provide the Stirling cycle engine which can be used at high temperature, keeping the heat insulation of a high temperature part and a low temperature part.

  The Stirling cycle engine according to the present invention includes a first cylinder and a second cylinder that are arranged in a casing with a central axis aligned, a displacer that is reciprocally inserted into the first cylinder, and the second cylinder. A piston inserted in a reciprocating manner, a high-temperature expansion chamber facing one end of the displacer, a low-temperature compression chamber facing the other end of the displacer and the piston, A gas flow path communicating with the expansion chamber and the compression chamber; and a heat storage heat exchanger for storing heat of the working gas flowing in the gas flow path, wherein at least one of the first cylinder and the displacer is a ceramic. Made of material or carbon material.

  Preferably, in the Stirling cycle engine, the sliding portion of the displacer that slides with the inner surface of the first cylinder is formed of a carbon material or a ceramic material.

  Preferably, the displacer is formed of a ceramic material, and is formed of a head portion facing the expansion chamber, formed of metal, a base portion that holds the head portion, and formed of a carbon material or a ceramic material. And the sliding portion provided on the outer surface.

  Suitably, the said sliding part has a ring-shaped sliding surface surrounding the perimeter of the said base part with a circular cross section.

  Preferably, the sliding portion of the piston that slides with the inner surface of the second cylinder is formed of a carbon material or a ceramic material.

  Preferably, the ceramic material forming at least one of the first cylinder and the displacer is an alumina based ceramic material, a zirconia based ceramic material, a silicon carbide based ceramic material, a silicon nitride based ceramic material, an aluminum nitride based ceramic material, It is a steatite ceramic material or a sialon ceramic material.

  ADVANTAGE OF THE INVENTION According to this invention, the Stirling cycle engine which can be used at high temperature can be provided, maintaining the heat insulation with a high temperature part and a low temperature part.

It is sectional drawing which shows an example of a structure of the Stirling cycle engine which concerns on embodiment of this invention. It is the figure which illustrated the principal part of the displacer and piston in the Stalin cycle engine shown in FIG.

  Hereinafter, a Stirling cycle engine applied to a generator will be described as an example of a Stirling cycle engine according to an embodiment of the present invention.

FIG. 1 is a cross-sectional view showing an example of the configuration of a Stirling cycle engine according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the main parts of the displacer and the piston in the Stalin cycle engine shown in FIG.
A Stirling cycle engine shown in FIG. 1 includes a casing 1, an upper cylinder 10 and a lower cylinder 11 housed in the casing 1, a displacer 70 inserted into the upper cylinder 10 so as to reciprocate, and a lower cylinder 11. Piston 20 inserted so as to be able to reciprocate, stator 30 and yoke 18 arranged facing the inside and outside of piston 20, magnet 25 attached to the cylindrical wall of piston 20, displacer A spring member (elastic member) 51 that biases 70 and a spring member (elastic member) 52 that biases the piston 20 are included.

  Here, the casing 1 is an example of the casing in the present invention, the upper cylinder 10 is an example of the first cylinder in the present invention, the lower cylinder 11 is an example of the second cylinder in the present invention, and the displacer 70 is the main cylinder. It is an example of the displacer in the invention, and the piston 20 is an example of the piston in the present invention.

The casing 1 is a sealed container in which working gas (helium gas or the like) of a Stirling cycle engine is enclosed. In the example of FIG. 1, the casing 1 is formed by combining an upper casing 2, an intermediate casing 3, a cylinder holding portion 5, and a lower casing 7.
The upper casing 2 and the intermediate casing 3 form a columnar internal space that mainly accommodates the upper cylinder 10. The inner wall on the ceiling side of the upper cylinder 10 is rounded like a dome. The cylinder holding part 5 is in contact with the outer periphery of the lower cylinder 11 on its inner wall, and holds the lower cylinder 11 so that the position of the central axis is determined.

  The lower casing 7 forms a cylindrical internal space that mainly accommodates the lower cylinder 11, the stator 30, the yoke 18, and the spring members 51 and 52. Near the bottom of the lower casing 7 is provided a support base 43 that supports the entire mechanism (the upper cylinder 10, the lower cylinder 11, etc.) in the casing 1 from below. An opening is provided in the center of the bottom of the lower casing 7, and the opening is closed by a lid 8. The lid portion 8 includes a pipe (not shown) for introducing working gas into the casing 1 and for passing electrical wiring.

  The upper cylinder 10 and the lower cylinder 11 each have a cylindrical shape, and are arranged in the casing 1 with the central axes aligned. When the upper cylinder 10 and the lower cylinder 11 are regarded as one cylinder, the displacer 70 is removably inserted into the upper end of the cylinder, and the piston 20 is reciprocally movable at the lower end of the cylinder. Inserted. The upper cylinder 10 and the lower cylinder 11 may be formed by connecting separate parts, or may be formed integrally.

  In the present embodiment, the upper cylinder 10 is formed of a ceramic material. As this ceramic material, a material having a higher heat resistance temperature than a resin material such as PPS and a lower thermal conductivity than a metal material such as stainless steel is used.

  The lower cylinder 11 is fixed to the support base 43 via a plurality of support columns 41. In the example of FIG. 1, the support column 41 is formed in a cylindrical shape, and a bolt 42 passes through a hole provided in the support base 43 and the cylindrical support column 41. The lower cylinder 11 is fixed to the support base 43 by screwing the male screw at the tip of the bolt 42 with the female screw on the lower surface of the lower cylinder 11. The spring member 51 has a hole through which the bolt 42 passes, and is fixed by being sandwiched between the support column 41 and the support base 43. In the example of FIG. 1, three spring members 51 are fixed to the support base 43.

  A space formed between the upper surface of the displacer 70 and the casing 1 is an expansion chamber 12 where the working gas is heated to increase its volume. On the other hand, the space formed between the displacer 70 and the piston 20 is the compression chamber 17, where the working gas is cooled to reduce its volume.

  A cylindrical space surrounded by the outer wall of the upper cylinder 10 and the inner wall of the casing 1 is a working gas flow path (gas flow path) that communicates the expansion chamber 12 and the compression chamber 17. A communication hole 16 connected to the compression chamber 17 is provided between the upper cylinder 10 and the lower cylinder 11. The expansion chamber 12 and the compression chamber 17 are connected through the communication hole 16 and the cylindrical space (gas flow path).

  In the cylindrical space (gas channel), a heat absorption fin 13, a heat storage heat exchanger (regenerator) 14, and a heat radiation fin 15 are arranged. The heat absorption fins 13 are disposed at positions close to the upper expansion chamber 12, the heat radiation fins 15 are disposed at positions close to the lower compression chamber 17, and the heat storage heat exchanger 14 is disposed between the heat absorption fins 13 and the heat radiation fins 15. Be placed. The heat storage heat exchanger 14 has a function of taking heat of the working gas flowing from the expansion chamber 12 to the compression chamber 17 and storing the heat, and giving the stored heat to the working gas flowing from the compression chamber 17 to the expansion chamber 12.

The casing 1 includes external fins 6 at portions that contact the heat radiating fins 15. The external fins 6 are heat radiating means for discharging the heat of the working gas to the outside of the casing 1. In the example of FIG. 1, the external fin 6 is fixed between the intermediate casing 3 and the cylinder holding portion 5. The external fins 6 are cooled by a cooling medium (water or the like) supplied from, for example, a pump (not shown) and held at a predetermined temperature.
On the other hand, the upper casing 2 is a heat absorbing means that transfers heat applied from an external heat source to the working gas in the expansion chamber 12, and the heat absorbing fins 13 are in contact with the inner wall of the upper casing 2.

The displacer 70 slides on the head 73 provided at one end facing the expansion chamber 12, the base 71 provided at the other end facing the compression chamber 17, and the inner surface of the upper cylinder 10. A sliding portion 72 and a cylindrical body 74.
The head portion 73 is an example of the head portion in the present invention, the base portion 71 is an example of the base portion in the present invention, and the sliding portion 72 is an example of the sliding portion in the present invention.

  The head portion 73 constitutes a wall surface that partitions the expansion chamber 12. The head portion 73 is formed of a ceramic material having a heat resistant temperature higher than that of a resin material such as PPS and lower thermal conductivity than that of a metal material such as stainless steel. By forming the head portion 73 from a ceramic material having a low thermal conductivity, heat conduction from the expansion chamber 12 to the compression chamber 17 is blocked.

  The base 71 constitutes a wall surface that partitions the compression chamber 17. The base portion 71 is made of, for example, a metal such as aluminum or brass, and holds the head portion 73 and the sliding portion 72. By forming the base 71 from a metal, the amount of deformation of the component due to temperature is smaller than when the base 71 is formed from a resin or the like. Accordingly, a decrease in mechanical accuracy at a high temperature is suppressed.

  The sliding portion 72 is provided on the outer surface of the base portion 71 so as to slide on the inner surface of the upper cylinder 10, and has a ring-shaped sliding surface surrounding the entire circumference of the base portion 71 having a circular cross section. The sliding portion 72 is formed of a carbon material that has a higher heat-resistant temperature than a resin material such as PPS and has a small deformation amount due to heat.

  A cylindrical body 74 having a diameter smaller than that of the base 71 is fixed to the end wall of the base 71 on the compression chamber 17 side so as to be coaxial with the base 71. In the example of FIG. 1, a circular recess is formed at the center of the end wall of the base 71, and the upper end of the cylindrical body 74 is inserted into this recess.

  The displacer 70 is connected to the spring member 51 via a rod 61 extending in parallel with the axial direction of the cylinder (10, 11). One end of the rod 61 is connected to the base 71 through the cavity of the cylindrical body 74 of the displacer 70. The other end of the rod 61 is connected to a plate-like spring member 51 attached to the support base 43 of the lower casing 7. The displacer 70 is urged in the vertical direction (cylinder axial direction) by the elastic force of the spring member 51 connected via the rod 61.

  The piston 20 includes a base portion 21 having a cylindrical shape and sliding portions 23 and 24 provided on the outer surface of the base portion 21. One end of the base 21 is closed by the end wall.

  The base portion 21 faces the displacer 70 at one end wall portion that is closed, and this end wall portion constitutes a wall surface that partitions the compression chamber 17. The base portion 21 is formed of a metal such as aluminum or brass, and holds the sliding portions 23 and 24. By forming the base portion 21 from a metal, the amount of deformation of the component due to temperature is smaller than when the base portion 21 is formed from resin or the like, so that a decrease in mechanical accuracy at high temperatures is suppressed.

  The sliding portions 23 and 24 are provided on the outer surface of the base portion 21 so as to slide on the inner surface of the lower cylinder 11, and ring-shaped sliding surfaces surrounding the entire circumference of the cylindrical base portion 21 are provided. Have. The sliding parts 23 and 24 are made of a carbon material having a higher heat resistance temperature and a smaller deformation amount due to heat than a resin material such as PPS.

  In the center of the end wall portion of the base portion 21 facing the displacer 70, a through portion 22 that receives the cylindrical body 74 of the displacer 70 is formed. In the example of FIG. 1, the penetrating portion 22 extends in a cylindrical shape parallel to the axial direction of the cylinder (10, 11). The cylindrical body 74 of the displacer 70 reciprocates up and down through the penetrating portion 22.

  The base 21 of the piston 20 is connected to a plate-like spring member 52 via a plurality of rods 62 extending in parallel with the axial direction of the cylinders (10, 11). In the example of FIG. 1, the spring member 52 is disposed between the lower cylinder 11 and the spring member 51, and is fixed to the lower cylinder 11 (or the support base 43) via a post (not shown). A through hole for passing the rod 61 is formed in the center of the spring member 52. One end of each of the plurality of rods 62 is connected to a symmetrical position around the through portion 22, and the other end is connected to a symmetrical position around the through hole of the spring member 52.

  A magnet 25 is fixed to the base 21 of the piston 20. The magnet 25 is provided in a ring shape so as to surround the entire circumference of the cylindrical base portion 21 between the separated sliding portions 23 and 24. A yoke 18 is fixed to the inner surface of the lower cylinder 11 facing the magnet 25. The yoke 18 is made of a magnetic material such as iron, and is formed, for example, in a ring shape so as to surround the magnet 25. A stator 30 is disposed inside the base portion 21 of the piston 20 at a position facing the yoke 18. The magnet 25 is sandwiched between the stator 30 and the yoke 18 and reciprocates up and down together with the piston 20. The magnet 25 generates a magnetic field that acts on the stator 30 and the yoke 18.

  The stator 30 includes a coil 33 formed by winding an electric wire in a ring shape, and a core 36 facing the yoke 18 with the coil 33 interposed therebetween.

  The coil 33 is disposed inside the cylindrical base portion 21 of the piston 20. Further, the coil 33 is arranged coaxially with the piston 20 so that the outer peripheral side thereof faces the magnet 25 of the piston 20.

  The core 36 is formed in a shape that surrounds the cross section of the coil 33 perpendicular to the winding direction of the electric wire, and a gap (a portion that does not surround the coil 33, a cut) is formed in a portion facing the magnet 25 and the coil 33. Have In the example of FIG. 1, the core 36 is divided into two blocks (36A, 36B) symmetrical in the vertical direction. The upper and lower blocks (36A, 36B) are respectively formed by overlapping and bonding thin magnetic material plates (silicon steel plates or the like).

  The core 36 is sandwiched between two parallel disk-shaped plate members, and the plate-shaped member is fixed to the support portion 40 by a coupling tool (not shown). The support portion 40 is fixed to the casing 1 together with the lower cylinder 11.

  Here, the operation of the Stirling cycle engine having the above-described configuration will be described.

  When the displacer 70 moves downward toward the piston 20, the compression chamber 17 becomes narrow, so that the working gas in the compression chamber 17 passes through the communication hole 16, the heat radiation fin 15, the heat storage heat exchanger 14, and the heat absorption fin 13. It flows into the hot expansion chamber 12. Since the working gas flowing into the expansion chamber 12 is heated and expands in volume, the pressure in the expansion chamber 12 and the compression chamber 17 increases. When the pressure in the expansion chamber 12 and the compression chamber 17 becomes higher than the pressure in the back pressure space 9 of the lower casing 7 defined by the piston 20, the piston 20 moves downward.

  When the pressure of the expansion chamber 12 and the compression chamber 17 decreases due to the downward movement of the piston 20 and becomes lower than the pressure of the back pressure space 9, the displacer 70 moves upward due to this pressure difference.

  When the displacer 70 moves upward, the expansion chamber 12 becomes narrow, so that the working gas in the expansion chamber 12 passes through the heat absorption fins 13, the heat storage heat exchanger 14, the heat radiation fins 15, and the communication holes 16, and the low temperature compression chamber 17. Flow into. Since the working gas that has flowed into the compression chamber 17 is cooled to reduce its volume, the pressure in the expansion chamber 12 and the compression chamber 17 is reduced. When the pressure in the expansion chamber 12 and the compression chamber 17 decreases, the moving direction of the piston 20 turns from the lower direction to the upper direction.

When the pressure of the expansion chamber 12 and the compression chamber 17 rises due to the upward movement of the piston 20 and becomes higher than the pressure of the back pressure space 9, the displacer 70 moves downward due to this pressure difference. When the displacer 70 moves downward toward the piston 20, the working gas again flows from the compression chamber 17 to the expansion chamber 12, the pressure in the expansion chamber 12 and the compression chamber 17 increases, and the movement direction of the piston 20 changes from the upward direction. Turn down.
By repeating the above, the displacer 70 and the piston 20 reciprocate up and down.

  When the piston 20 reciprocates, the magnet 25 moves up and down between the yoke 18 and the stator 30, and the magnetic field of the coil 33 changes periodically, so that an electromotive force is generated in the coil 33 and a current flows.

  As described above, in the Stirling cycle engine according to the present embodiment, the displacer 70 and the upper cylinder 10 that accommodates the displacer 70 are formed of a ceramic material. Thereby, it is possible to operate continuously at a significantly higher temperature than a conventional Stirling cycle engine in which the displacer and the cylinder are formed of a resin material. Therefore, the Stirling cycle engine according to the present embodiment is applicable to, for example, a concentrating solar thermal power generation apparatus in which the high temperature part reaches a temperature in the 800 ° C. range.

  In addition, according to the Stirling cycle engine according to the present embodiment, the high-temperature expansion chamber and the low-temperature compression chamber are compared with the conventional Stirling cycle engine in which the displacer and the cylinder are made of a metal such as stainless steel having high thermal conductivity. Therefore, the efficiency of power generation can be improved.

  Furthermore, according to the Stirling cycle engine according to the present embodiment, the weight of the apparatus can be reduced by using a light weight ceramic material instead of a heavy metal material.

  In addition, according to the Stirling cycle engine according to the present embodiment, by using a ceramic material for the displacer 70 and the upper cylinder 10, it becomes possible to mold these parts using a metal mold. The number of parts can be reduced compared to.

  Further, in the Stirling cycle engine according to the present embodiment, the sliding portion 72 of the displacer 70 and the sliding portions 23 and 24 of the piston 20 that slide with the inner surfaces of the cylinders (10, 11) are formed of a carbon material. As a result, it is possible to continuously operate at a higher temperature as compared with a conventional Stirling cycle engine that uses a resin material for sliding parts of the displacer and the piston. In general, since a resin material has a large amount of deformation due to heat, when it is used for a sliding portion, there is a problem that deformation occurs at a high temperature and sliding performance is lowered. According to the present embodiment, by using a carbon material having a small deformation amount due to temperature, stable sliding performance can be maintained even at a high temperature, so that continuous operation for a long time is possible.

  In addition, this invention is not limited only to embodiment mentioned above, The other various variation is included.

In the above-described embodiment, the displacer 70 is provided with the metal base 71 and the carbon material sliding portion 72, but the present invention is not limited to this example. In another embodiment of the present invention, the base portion and the sliding portion of the displacer may be integrally formed of a carbon material.
In the above-described embodiment, the piston 20 is provided with the metal base 21 and the sliding portions 23 and 24 of the carbon material. However, in another embodiment of the present invention, the piston base and the sliding portion are made of the carbon material. May be formed integrally.

In the above-described embodiment, the sliding portions (72, 23, 24) in the displacer 70 and the piston 20 are formed of a carbon material, but the present invention is not limited to this. In another embodiment of the present invention, the displacer and the sliding portion of the displacer may be formed of a ceramic material. Also in this case, the heat resistance can be improved as compared with a conventional Stirling cycle engine in which the sliding portion is formed of a resin material.
In another embodiment of the present invention, the base portion and sliding portion of the displacer may be integrally formed of a ceramic material, or the entire displacer including the head portion may be integrally formed of a ceramic material. Also good.
In another embodiment of the present invention, the base portion and the sliding portion of the piston may be integrally formed of a ceramic material.

  In the embodiment described above, the head portion 73 of the displacer 70 is formed of a ceramic material, but the present invention is not limited to this. In another embodiment of the present invention, the head portion of the displacer may be made of a carbon material. In that case, the entire displacer including the base portion and the sliding portion may be integrally formed of a carbon material.

  In the above-described embodiment, the upper cylinder 10 is formed of a ceramic material, but the present invention is not limited to this example. In another embodiment of the present invention, the cylinder in which the displacer is accommodated may be formed of a carbon material. Also in this case, the heat resistance can be greatly improved as compared with a conventional Stirling cycle engine using a cylinder made of resin material.

  The ceramic material used for the displacer and the cylinder in the above-described embodiment is arbitrary, for example, an alumina-based ceramic material, a zirconia-based ceramic material, a silicon carbide-based ceramic material, a silicon nitride-based ceramic material, an aluminum nitride-based ceramic material, Examples thereof include steatite ceramic materials and sialon ceramic materials. The ceramic material used for the displacer and the sliding portion of the piston is also arbitrary. For example, the above ceramic materials can be given as examples.

  In the embodiment described above, an example of a generator of a Stirling cycle engine is given, but the present invention is not limited to this, and can be applied to a cooling device of a Stirling cycle engine, for example.

DESCRIPTION OF SYMBOLS 1 ... Casing, 2 ... Upper casing, 3 ... Middle part casing, 5 ... Cylinder holding part, 6 ... External fin, 7 ... Lower casing, 8 ... Cover part, 10 ... Upper cylinder, 11 ... Lower cylinder, 12 ... Expansion chamber , 13 ... endothermic fins, 14 ... heat storage heat exchanger (regenerator), 15 ... radiating fins, 16 ... communication hole, 17 ... compression chamber, 18 ... yoke, 19 ... yoke holding part, 20 ... piston, 21 ... base part , 22 ... penetrating part, 23, 24 ... sliding part, 25 ... magnet, 30 ... stator, 33 ... coil, 36 ... core, 40 ... support part, 41 ... column, 43 ... support base, 51, 52 ... Spring member, 61, 62 ... rod, 70 ... displacer, 71 ... base, 72 ... sliding part, 73 ... head part.

Claims (6)

A first cylinder and a second cylinder arranged in a casing with the central axis aligned,
A displacer inserted into the first cylinder in a reciprocable manner;
A piston inserted into the second cylinder so as to reciprocate;
A high-temperature expansion chamber facing one end of the displacer;
A cold compression chamber facing the other end of the displacer and the piston;
A gas flow path communicating the expansion chamber and the compression chamber;
A heat storage heat exchanger for storing heat of the working gas flowing in the gas flow path,
At least one of the first cylinder and the displacer is formed of a ceramic material or a carbon material;
Stirling cycle agency. A sliding portion of the displacer that slides with the inner surface of the first cylinder is formed of a carbon material or a ceramic material;
The Stirling cycle engine according to claim 1. The displacer is
A head portion formed of a ceramic material and facing the expansion chamber;
A base formed of metal and holding the head portion;
The sliding portion formed of a carbon material or a ceramic material and provided on the outer surface of the base portion,
The Stirling cycle engine according to claim 2. The sliding portion has a ring-shaped sliding surface surrounding the entire circumference of the base portion having a circular cross section.
The Stirling cycle engine according to claim 3. The sliding portion of the piston that slides with the inner surface of the second cylinder is formed of a carbon material or a ceramic material.
The Stirling cycle engine according to any one of claims 1 to 4. The ceramic material forming at least one of the first cylinder and the displacer is an alumina-based ceramic material, a zirconia-based ceramic material, a silicon carbide-based ceramic material, a silicon nitride-based ceramic material, an aluminum nitride-based ceramic material, or a steatite-based material. A ceramic material or a sialon-based ceramic material,
The Stirling cycle engine according to any one of claims 1 to 5.