JP2003166768A - Stirling engine and its operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Stirling engine to cause no collision between a piston and a displacer even when the engine is operated on a high input condition right after a start of operation and to provide its operation method. <P>SOLUTION: The Stirling engine comprises: a piston 3 fitted in a cylinder 1 filled with working gas and driven by a drive means 7 for reciprocation; a displacer 2 fitted in the cylinder 1 and reciprocated with a phase difference with that of the piston 3; a compression chamber 4 partitioned between the piston 3 and the displacer 2; an expansion chamber 5 positioned on the opposite side to the compression chamber 4 with the displacer 2 nipped therebetween; and a heater 17 to promote a temperature difference between a working gas temperature in the compression chamber 4 and working gas temperature in the expansion chamber 5 during non-steady operation motion right after starting of operation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Stirling engine, and more particularly to a Stirling engine capable of operating at a high output immediately after the start of operation by providing a mechanism for preventing a collision between a piston and a displacer immediately after the start of operation and a method of operating the same. Regarding

[0002]

2. Description of the Related Art FIG. 14 is a schematic sectional view for explaining the structure of a conventional general Stirling engine. Here, the structure of a Stirling refrigerator using a Stirling engine will be described as an example.

In a free piston type Stirling refrigerator, a piston 3 and a displacer 2 are coaxially fitted in a cylinder 1 having a cylindrical space therein, so that a compression chamber 4 is provided between the piston 3 and the displacer 2. To
Further, expansion chambers 5 are formed between the displacer 2 and the closed end of the cylinder 1. A regenerator 6 is installed between the compression chamber 4 and the expansion chamber 5, and the compression chamber 4, the expansion chamber 5 and the regenerator 6 form a closed circuit.

The closed circuit is filled with an inert gas such as helium. The piston 3 fitted in the cylinder 1 is driven by driving means such as a linear motor 7 and reciprocates in the cylinder 1 in the axial direction. The reciprocating movement of the piston 3 causes a periodic pressure change in the working gas in the compression chamber 4, and the pulsation of the back pressure increased with the compression causes the working gas to flow into the expansion chamber 5 via the regenerator 6. Inflow. The movement of the working gas into the expansion chamber 5 at this time causes periodical vibration in the displacer 2.

The displacer 2 is fixed to one end of a displacer rod 8, and the other end of the displacer rod 8 is attached to a main body casing 15 via a spring 9. The displacer rod 8 is arranged so as to penetrate an axial through hole provided in the piston 3. Due to the vibration generated by the flow of the working gas into the expansion chamber 5 and the elastic force of the spring 9, the displacer 2 has the same cycle as the piston 3,
It reciprocates with a certain phase difference. With the above configuration and operation, the known Stirling cycle, which is a known thermodynamic cycle, is configured in the closed circuit, and the cooling unit 1
The outside air in the vicinity of 3 is cooled to an extremely low temperature.

Hereinafter, the principle of the reverse Stirling cycle will be described in detail. When the working gas in the compression chamber 4 compressed by the piston 3 moves to the expansion chamber 5 via the regenerator 6, it is pre-cooled by the cold heat stored in the regenerator 6 half a cycle before. At this time, the heat in the compression chamber 4 taken out by the high temperature side internal heat exchanger 10 is released to the outside by the heat radiating portion 11. When the working gas flows into the expansion chamber 5, the displacer 2 is pushed by the pressure increase in the expansion chamber 5, and the expansion in the expansion chamber 5 starts.

After that, when the expansion has progressed to a certain extent, the displacer 2 is pushed back by the restoring force of the piston 3, and the working gas in the expansion chamber 5 starts moving to the compression chamber 4 again via the regenerator 6. At this time, the low temperature side internal heat exchanger 12 removes heat from the outside via the cooling unit 13, so that the outside air in the vicinity of the cooling unit 13 is cooled. After most of the working gas returns to the compression chamber 4, the working gas in the compression chamber 4 is compressed by the piston 3 again, and the process proceeds to the next cycle. By continuously repeating the above-described series of cycles, the cryogenic temperature is taken out from the Stirling refrigerator.

During a steady operation after a lapse of a certain time from the start of operation, the temperature difference between the heat radiating portion and the cooling portion is in a stable state with a substantially constant temperature. Correspondingly, a certain temperature difference also occurs in the working gas in the compression chamber and the expansion chamber. In this case, since a heat output proportional to the square of the piston amplitude is generated, the reciprocating motion of the piston is suppressed to a state in which a constant load is applied when viewed from the linear motor. Further, the displacer receives the reciprocating force of the piston and reciprocates with a constant phase difference, so that the piston and the displacer do not collide with each other by maintaining the balance between them. It is said that the optimum constant phase difference is about 90 °.

[0009]

However, during unsteady operation immediately after the start of operation of the Stirling refrigerator, such as when the operation has been stopped for a long time or when the operation is started for the first time when the apparatus is purchased, The temperature of the heat radiating part and the cooling part is the ambient temperature, and there is almost no difference in temperature between the heat radiating part and the cooling part. Therefore, there is almost no temperature difference between the working gas temperature in the compression chamber and the working gas temperature in the expansion chamber, and the piston is in the unloaded state.

In this state, when the Stirling refrigerator receives the same input as in the steady operation, the swing width of the piston becomes larger than that in the steady operation. Further, the phase difference between the piston and the displacer has not reached the desired phase difference, and is in a state of being almost in a reverse phase. Therefore, if the input to the Stirling refrigerator is not controlled, there is a risk of collision between the piston and the displacer. Should the piston and displacer collide, damage to the Stirling refrigerator is unavoidable.

When this Stirling refrigerator is used in a refrigerator or refrigerator, the operation of the refrigerator is temporarily suspended in order to defrost an external heat exchanger (not shown) attached to the heat radiating portion. It may be stopped. In this case as well, the temperature of the cooling unit rises and the temperature of the heat dissipation unit falls, so the temperature difference decreases. Therefore, when the operation is restarted, the swing width becomes larger than the swing width of the piston during the steady operation, and there is a risk that the piston and the displacer collide.

In the conventional Stirling refrigerator, when the unsteady operation is performed immediately after the start of operation, the electric power input to the linear motor is suppressed to be lower than that in the steady operation, so that the swing width of the piston is suppressed and the piston and the displacer collide. Was prevented. However, in this method, the maximum swing operation of the Stirling refrigerator cannot be performed because the swing width of the piston is suppressed, so rapid cooling cannot be performed, and it takes a considerable time to reach the steady operation.

Therefore, it is an object of the present invention to provide a Stirling engine and a method of operating the Stirling engine, in which there is no risk of collision between the piston and the displacer even when the engine is operated under high input conditions immediately after the start of operation.

[0014]

A Stirling engine of the present invention is fitted in a cylinder, and is reciprocated by a piston driven by a driving means and reciprocated by a piston. A displacer, a compression chamber defined between the piston and the displacer, an expansion chamber located on the opposite side of the compression chamber with the displacer interposed, and a temperature difference between the temperature inside the compression chamber and the temperature inside the expansion chamber are promoted. And a temperature difference promoting means.

The temperature difference promoting means is provided as in the present construction, and the operating gas temperature in the compression chamber and the working gas temperature in the expansion chamber are intentionally changed by using the temperature difference promoting means at the time of unsteady operation such as the start of operation. Since a heat load is applied to the piston by promoting the temperature difference of 1 to a predetermined temperature difference, collision between the piston and the displacer is prevented. As a result, it becomes possible to operate the Stirling engine immediately after the start of operation under conditions close to the steady operation. As a result, when a Stirling engine is used as a refrigerating engine, for example, the freezing / refrigerating quenching can be realized immediately after the start of operation.
The temperature difference promoting means here does not include means for changing the temperature of the working gas in the compression chamber or the expansion chamber by compressing / expanding the working gas (for example, the piston or the displacer itself).

In the above Stirling engine of the present invention, for example, the temperature difference detecting means for further detecting the temperature difference and the temperature difference promoting means when the temperature difference detected by the temperature difference detecting means reaches a predetermined temperature difference. It is desirable to have a control means for stopping the operation of.

As in this configuration, by providing the temperature difference detecting means and the control means for controlling the operation of the temperature difference promoting means based on the temperature difference information detected by the temperature difference detecting means, a predetermined value is provided. It becomes possible to stop the operation of the unnecessary temperature difference promoting means at the time when the temperature difference (the temperature difference during the steady operation or a temperature difference close thereto) is reached. As a result, the temperature difference between the compression chamber and the expansion chamber is prevented from becoming excessively large after the transition to the steady operation operation, so that it is possible to provide a Stirling engine that operates efficiently.

In the above Stirling engine of the present invention, for example, the temperature difference promoting means preferably comprises heating means for heating the compression chamber.

With this structure, the temperature difference between the compression chamber and the expansion chamber can be promoted by intentionally heating the working gas in the compression chamber by the heating means. In addition,
This heating means forcibly raises the temperature of the working gas in the compression chamber, in addition to the temperature of the working gas in the compression chamber being increased by being compressed by the piston and the displacer.

In the above Stirling engine of the present invention, for example, it is preferable that the heating means comprises a heater disposed inside the compression chamber.

By installing the heater in the compression chamber as in the present construction, it becomes possible to easily construct the heating means as the temperature difference promoting means. In particular, by providing the heater in the compression chamber, it is possible to directly heat the working gas in the compression chamber, so that it becomes possible to lead to a steady operation operation in a shorter time.

In the above Stirling engine of the present invention, for example, the heating means may be a heater arranged outside the compression chamber.

It is possible to heat the working gas in the compression chamber through the cylinder by installing a heater outside the compression chamber as in this configuration. This configuration is particularly effective when the heater cannot be directly provided in the compression chamber.

The Stirling engine of the present invention is provided with, for example, a heat radiating section made of a metal material for radiating the heat in the compression chamber to the outside, and the heating means applies a voltage to the heat radiating section to flow an electric current. Therefore, it may be a voltage applying means for heating the working gas in the compression chamber.

As in this structure, the heat radiation portion for releasing the heat in the compression chamber to the outside during the steady operation is made of a conductive material, and the voltage is applied to the heat radiation portion to flow the current during the unsteady operation. As a result, it is possible to heat the heat dissipation portion and heat the working gas in the compression chamber.
This configuration is particularly effective when the heater cannot be directly installed in the Stirling engine.

In the above Stirling engine of the present invention, for example, it is preferable that the temperature difference promoting means comprises a heater for heating the working gas in the back pressure chamber which is located on the opposite side of the compression chamber with the piston interposed and communicates with the compression chamber. .

It is possible to promote the temperature difference between the compression chamber and the expansion chamber by heating the working gas in the back pressure chamber instead of heating the working gas in the compression chamber as in this configuration. is there. This is because the compression chamber and the expansion chamber communicate with each other, so that the working gas flows back and forth. In this case, the position where the heater is installed is not particularly limited as long as it can heat the working gas in the back pressure chamber, and it may be inside or outside the back pressure chamber.

In the above Stirling engine of the present invention, for example, the temperature difference promoting means preferably comprises a heat storage means for accumulating heat so that the heat in the compression chamber is not released to the outside.

As in this configuration, it is possible to configure the temperature difference promoting means by the heat storage means. The term “outside” as used herein means the outside of the Stirling engine.
Unlike the above method of directly heating the working gas in the compression chamber, the heat generated during the steady operation is stored in the heat storage means, and this heat is used during the unsteady operation to heat the working gas in the compression chamber. By doing so, it becomes possible to promote the temperature difference between the two chambers with a simpler configuration. When such a heat storage means is provided, the effect cannot be obtained because not only the compression chambers and expansion chambers but also the heat storage means have the ambient temperature at the start of the operation at the time of purchase of the apparatus, but for example, a Stirling refrigerator. It is particularly effective for temporary stoppage of operations such as during defrosting work in.

In the above Stirling engine of the present invention, for example, the heat storage means is preferably made of a heat storage material arranged outside the compression chamber.

By configuring the heat storage means with a heat storage material as in this configuration, it becomes possible to facilitate the temperature difference between the two chambers more easily. In this case, it is preferable that the heat storage material is provided outside the compression chamber so that the temperature of the working gas in the compression chamber does not rise excessively during steady operation.

The above Stirling engine of the present invention is provided with, for example, a circulation passage through which a heat medium for exchanging heat between the compression chamber and the outside is circulated, and the heat storage means is arranged in this circulation passage. preferable.

As in this structure, the heat storage means is provided in the circulation path for exchanging heat between the working gas in the compression chamber and the outside, so that the heat storage means releases the heat from the compression chamber to the outside during the operation of the Stirling engine. The stored heat can be stored. After this, even when the Stirling engine is temporarily stopped, the heat is stored by the heat storage means provided in the circulation path, so this heat is exchanged with the working gas in the compression chamber again after the restart of the operation. It is possible to raise the temperature of the working gas in the compression chamber.

In the above Stirling engine of the present invention, for example, it is desirable that the circulation path has a branch path, and the heat storage means is disposed in this branch path.

By providing a separate branch path in the circulation path and arranging the heat storage means in this branch path as in the present configuration, the path through which the heat medium circulates during steady operation and the heat medium during unsteady operation are provided. Since it is possible to change the distribution route, heat exchange can be performed more efficiently.

In the above Stirling engine of the present invention, for example, the temperature difference promoting means preferably comprises a cooling means for cooling the expansion chamber.

With this configuration, it is possible to promote the temperature difference between the compression chamber and the expansion chamber by intentionally cooling the working gas in the expansion chamber by the cooling means. In addition,
This cooling means forcibly lowers the temperature of the working gas in the expansion chamber, in addition to the temperature of the working gas in the expansion chamber expanded by the displacer to lower the temperature.

In the above Stirling engine of the present invention, for example, it is desirable that the temperature difference promoting means comprises a cold storage means for accumulating heat so that the heat in the expansion chamber is not transferred to the outside.

As in this structure, it is possible to configure the temperature difference promoting means by the cold storage means. The term “outside” as used herein means the outside of the Stirling engine.
Unlike the above-described method of directly cooling the working gas in the expansion chamber, the cold heat generated during the steady operation operation is stored in the cold storage means, and this cold heat is used during the unsteady operation operation to cool the working gas inside the expansion chamber. By doing so, it becomes possible to promote the temperature difference between the two chambers with a simpler configuration. When such a cool storage means is provided, the effect cannot be obtained because not only the compression chamber and the expansion chamber but also the cool storage means are at the ambient temperature at the start of the operation at the time of purchase of the apparatus, but for example, a Stirling refrigerator. It is particularly effective for temporary stoppage of operations such as during defrosting work in.

The above Stirling engine of the present invention is provided with, for example, a circulation passage through which a heat medium for exchanging heat between the expansion chamber and the outside is circulated, and the cold storage means is arranged in this circulation passage. desirable.

As in this structure, by providing the cool storage means in the circulation path for exchanging heat between the working gas in the expansion chamber and the outside, the cool storage means discharges the expansion gas from the expansion chamber to the outside during operation of the Stirling engine. It becomes possible to store the stored cold heat. For this reason, even when the Stirling engine is temporarily stopped, cold heat is stored by the cold storage means provided in the circulation path, and therefore this cold heat exchanges heat with the working gas in the compression chamber again after the restart of operation,
It is possible to intentionally raise the temperature of the working gas in the compression chamber.

In the above Stirling engine of the present invention, for example, it is preferable that the circulation path has a branch path, and the cold storage means is disposed in the branch path.

By providing a separate branch path in the circulation path and arranging the cold storage means in the branch path as in the present configuration, the path through which the heat medium circulates during steady operation and the heat medium during unsteady operation are provided. Since it is possible to change the distribution route, heat exchange can be performed more efficiently.

The operating method of the Stirling engine of the present invention is as follows.
A piston fitted in a cylinder and reciprocated by driving means, a displacer reciprocating with a phase difference from the piston, a compression chamber defined between the piston and the displacer, and a compression chamber sandwiching the displacer. A method for operating a Stirling engine having an expansion chamber located on the opposite side of the expansion chamber, which promotes expansion of the temperature difference between the compression chamber and the expansion chamber at the start of operation, and when the temperature difference reaches a predetermined temperature difference. It is characterized by stopping the promotion of the temperature difference.

By operating the Stirling engine using this operating method, the maximum output operation can be performed during the unsteady operation operation by promoting the expansion of the temperature difference, and the expansion of the temperature difference can be achieved after the transition to the steady operation operation. By stopping the promotion, it is possible to prevent output reduction due to excessive temperature difference between the compression chamber and the expansion chamber. Therefore, it is possible to always perform the maximum output operation when the Stirling engine is operating.

In the method of operating the Stirling engine of the present invention, for example, the Stirling engine has a flow passage through which a heat medium for exchanging heat between the compression chamber and the outside flows, and a flow for causing the heat medium in the flow passage to flow. It is also realized by stopping the flow means to promote the expansion of the temperature difference and by operating the flow means to stop the promotion of the temperature difference expansion.

When the means for promoting the expansion of the temperature difference is composed of the circulation path and the flow means for flowing the heat medium in the circulation path as in the present construction, the flow means is stopped during the unsteady operation. It is also possible to suppress the heat exchange between the working gas in the compression chamber and the outside, promote the temperature rise in the compression chamber, and promote the temperature difference between the compression chamber and the expansion chamber. In this case as well, like the present operating method, the heat exchange performance is improved by operating the fluidizing means after the transition to the steady operation.

In the method of operating the Stirling engine of the present invention, for example, the Stirling engine has a flow passage through which a heat medium for exchanging heat between the expansion chamber and the outside flows, and a flow for causing the heat medium in the flow passage to flow. It is also realized by stopping the flow means to promote the expansion of the temperature difference and by operating the flow means to stop the promotion of the temperature difference expansion.

When the means for promoting the expansion of the temperature difference is composed of the circulation path and the flow means for flowing the heat medium in the circulation path as in the present construction, the flow means is stopped during the unsteady operation. It is also possible to suppress the heat exchange between the working gas in the expansion chamber and the outside, promote the decrease of the temperature in the expansion chamber, and promote the temperature difference between the compression chamber and the expansion chamber. In this case as well, like the present operating method, the heat exchange performance is improved by operating the fluidizing means after the transition to the steady operation.

[0050]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In addition, the explanation will be given here also by exemplifying a Stirling refrigerator using a Stirling engine. Further, the same parts as those described in the above-mentioned conventional example are designated by the same reference numerals in the drawings, and the description thereof will not be repeated.

(Embodiment 1) FIG. 1 is a schematic cross-sectional view for explaining the structure of a Stirling refrigerator in Embodiment 1 of the present invention. The Stirling refrigerator in the present embodiment includes a heater 17 inside the compression chamber 4. The heater 17 is attached so as to be able to intentionally heat the working gas in the compression chamber 4 immediately after the start of the operation of the Stirling refrigerator until the steady operation state is reached.

As a method for determining whether the steady state has been reached from the unsteady state immediately after the start of operation, for example, in the Stirling refrigerator, the high temperature side temperature detecting sensor 47 for detecting the working gas temperature in the compression chamber 4 is used. And a low temperature side temperature detection sensor 48 for detecting the temperature of the working gas in the expansion chamber 5, and a temperature difference is calculated based on the temperature information detected by these temperature detection sensors 47, 48. It is possible to judge whether or not the temperature difference that converges during operation has been reached. If the temperature difference during steady operation is reached,
Control means provided in the Stirling refrigerator (not shown)
Thus, the operation of the heater 17 is stopped, and stable steady operation is realized.

In the Stirling refrigerator according to the present embodiment, the heater 17 is provided inside the compression chamber 4 so that the working gas in the compression chamber 4 is directly heated immediately after the start of operation, and the working gas in the compression chamber 4 is directly heated. Since it is possible to raise the temperature, it is possible to cause a large temperature difference between the working gas temperature in the compression chamber 4 and the working gas temperature in the expansion chamber 5. As a result, a heat load is applied to the piston 3, and it becomes possible to operate in a state close to a steady operation operation. If the heater cannot be installed in the compression chamber 4 due to the design, it is possible to install the heater outside the compression chamber 4. For example, as shown in FIG. 2, the heater 18 may be attached to the outside of the heat radiating portion 11 that radiates the heat of the compression chamber 4 to the outside.

(Second Embodiment) FIG. 3 is a schematic sectional view for explaining the structure of a Stirling refrigerator in the second embodiment of the present invention. In the Stirling refrigerator according to the present embodiment, the heat radiation portion 11 for discharging the working gas inside the compression chamber 4 to the outside is made of a metal material (for example, copper).
It consists of A voltage applying unit is electrically connected to the heat radiating unit 11, and a voltage is applied by the voltage applying unit so that a current flows and the heat radiating unit 11 is heated. It is desirable to prevent current from flowing to other parts by forming all the parts in contact with the heat dissipation part 11 with a material having high electric and low efficiency such as stainless steel.

With this configuration, the heat radiating portion 11 is heated by the voltage applying means, and this heat is transferred to the working gas inside the compression chamber 4, whereby the working gas temperature inside the compression chamber 4 is intentionally raised. It becomes possible. This configuration is particularly effective when a separate heater cannot be provided inside or outside the compression chamber 4 as in the first and second embodiments described above.

(Third Embodiment) FIG. 4 is a schematic sectional view for explaining the structure of a Stirling refrigerator in the third embodiment of the present invention. In the Stirling refrigerator according to the present embodiment, the heater 33 is installed outside the main body casing 15 that forms the back pressure chamber 14 located on the opposite side of the compression chamber 4 with the piston 3 interposed therebetween. Usually piston 3
Are fitted with a slight gap for sliding in the cylinder 1. Therefore, the back pressure chamber 14 and the compression chamber 4 communicate with each other through this gap. Further, there may be a case where a mechanism for returning the working gas flowing into the back pressure chamber 14 to the compression chamber 4 again is provided. As described above, since the back pressure chamber 14 and the compression chamber 4 communicate with each other, the working gas can come and go to some extent during the operation of the Stirling refrigerator.

Therefore, by heating the working gas in the back pressure chamber 14, it becomes possible to raise the temperature of the working gas in the compression chamber 4. However, in this case, since the efficiency of raising the temperature of the working gas in the compression chamber 4 is lower than that in the first and second embodiments, it is preferable to use the auxiliary heating means. Further, as shown in FIG. 5, a heater 34 is provided in the back pressure chamber 14, or as shown in FIG. 6, the heater 3 is provided at a position away from the main body casing of the Stirling refrigerator.
5 may be installed.

(Fourth Embodiment) FIG. 7 is a schematic sectional view for explaining the structure of a Stirling refrigerator in the fifth embodiment of the present invention. In the Stirling refrigerator of this embodiment, the heat storage material 32 is installed near the compression chamber 4. The heat storage material 32 stores the heat radiated from the compression chamber 4.

With this structure, the heat storage material 32 accumulates the heat released from the compression chamber 4 inside the Stirling refrigerator during the steady operation of the Stirling refrigerator and accumulates the heat for a certain period even when the Stirling refrigerator is stopped. It is possible to set. As a result, compared to the case without the heat storage material 32,
The temperature decrease in the compression chamber 4 after the operation is stopped becomes gentle. By performing the defrosting operation during this period, the temperature of the working gas in the compression chamber 4 at the time of restarting the operation of the Stirling refrigerator is suppressed to a minimum temperature decrease due to the heat storage effect of the heat storage material 32. It is possible to keep it high. As a result, the working gas in the compression chamber 4 and the expansion chamber 5
Since a temperature difference with the working gas inside is secured to some extent, it is possible to apply a heat load to the piston 3 immediately after restarting the operation.

(Fifth Embodiment) FIG. 8 is a schematic sectional view for explaining the structure of a Stirling refrigerator in the fifth embodiment of the present invention. The Stirling refrigerator in the present embodiment is provided with a flow passage 23 through which a heat medium that radiates the heat in the compression chamber 4 to the outside flows during the steady operation. In the present embodiment, a so-called air-cooled flow passage in which air is used as a heat medium flowing in the flow passage 23 is configured. In this case, the air is forced to contact the external heat exchanger 21 provided outside the compression chamber 4 by the blower fan 22 that is a flow means installed in the flow passage 23, and the air and the external heat exchange are performed. The heat in the compression chamber 4 is released to the outside by causing the vessel 21 to exchange heat.

In the Stirling refrigerator according to the present embodiment, the operation of the blower fan 22 is intentionally stopped during the unsteady operation. As a result, the heat exchange performance of the external heat exchanger 21 decreases, and the temperature of the working gas in the compression chamber 4 approaches the steady-state temperature faster than when the blower fan 22 is operated, and the expansion of the working gas in the compression chamber 4 increases. It is possible to quickly lead the temperature difference in the chamber 5 to a predetermined temperature difference. Further, as shown in FIG. 9, a heater 19 may be installed in the flow passage 23 and the heater 19 may be operated during unsteady operation. In this case, it is possible to raise the temperature of the working gas in the compression chamber 4 more efficiently by operating the blower fan.

(Sixth Embodiment) FIG. 10 is a schematic sectional view for explaining the structure of a Stirling refrigerator in the sixth embodiment of the present invention. The Stirling refrigerator according to the present embodiment includes a circulation path 24 through which a heat medium that radiates the heat in the compression chamber 4 to the outside flows during steady operation. In the present embodiment, a so-called liquid cooling type circulation path is used in which a liquid is used as the heat medium flowing through the circulation path 24. In this case, the liquid is forcibly brought into contact with the heat radiating portion 11 provided outside the compression chamber 4 by the circulation pump 27, which is a flow means, to cause heat exchange between the liquid and the heat radiating portion. The heat inside is released to the outside.

In the Stirling refrigerator according to the present embodiment, the operation of the circulation pump 27 is intentionally stopped during the unsteady operation. As a result, the heat exchange efficiency between the heat radiating portion 11 and the heat medium decreases, and the heat in the compression chamber 4 remains in the room.
As a result, the temperature in the compression chamber 4 approaches the temperature in the steady state sooner than in the case where the circulation pump 27 is operated, and the temperature difference between the compression chamber 4 and the expansion chamber 5 is swiftly increased by the predetermined temperature difference. It is possible to lead.

Further, as shown in FIG.
In addition to the external radiator 26, it may be possible to provide a reserve tank 25, which is a heat storage means and has heat retention performance.
The reserve tank 25 is in a state where heat is still accumulated even during a temporary stop (for example, during defrosting work) due to the operation of the Stirling engine, and this heat is used to compress the heat when the operation of the Stirling engine is restarted. The working gas in the chamber 4 may be quickly heated.

Further, as shown in FIG. 11, it is conceivable to provide a branch passage 28 in the circulation passage 24 and install a heat storage material 29 in the branch passage. In this case, the heat medium is circulated in both the circulation path with the external cooler 26 and the branch path 28 during the steady operation, and the heat medium is circulated only in the branch path 28 by the switch 30 during the unsteady operation. By doing so, the temperature of the working gas in the compression chamber 4 is maintained by the heat accumulated in the heat storage material 29 even after the operation is stopped (for example, during defrosting work). The temperature difference between the working gas temperature inside and the working gas temperature inside the expansion chamber 5 can be maintained for a long time.

(Embodiment 7) FIG. 12 is a schematic sectional view for explaining the structure of a Stirling refrigerator in Embodiment 7 of the present invention. The Stirling refrigerator in the present embodiment is provided with a circulation path 45 through which a heat medium for transferring the cold heat in expansion chamber 5 to freezer / refrigerator 42 during steady operation flows. In the present embodiment, this circulation path 45
A so-called liquid-cooling type flow passage using a liquid as a heat medium flowing therein is provided. In this case, the external heat exchanger 43 provided outside the expansion chamber 5 is forced to come into contact with the liquid by the circulation pump 44 to cause heat exchange between the cooling unit 13 and the liquid, and the cold heat in the expansion chamber 5 is removed. Heat is transferred to the freezer / refrigerator 42.

In the Stirling refrigerator according to the present embodiment, the operation of the circulation pump 44 is intentionally stopped during the unsteady operation. As a result, the heat exchange performance of the external heat exchanger 43 deteriorates, and the cold heat in the expansion chamber 5 is accumulated. As a result, the temperature in the expansion chamber 5 approaches the temperature in the steady state sooner than when the circulation pump 44 is operated, and the temperature difference between the compression chamber 4 and the expansion chamber 5 is quickly guided by the predetermined temperature difference. It becomes possible.

(Embodiment 8) FIG. 13 is a schematic sectional view for explaining the structure of a Stirling refrigerator in Embodiment 8 of the present invention. The Stirling engine according to the present embodiment includes a circulation path 37 connected to an external heat exchanger 46 to take out cold heat of the expansion chamber 5. A blower fan 36 is provided in the circulation path 37, whereby air circulates in the circulation path. A branch path 38 is provided in the circulation path 37, and the cool storage material 3 is provided in the branch path 38.
9 are installed.

In this case, the freezer / refrigerator 4 is operated during steady operation.
Air is circulated in both the 2 and the branch passage 38. Thereby, the temperature of the working gas in the expansion chamber 5 is maintained by the cold heat accumulated in the regenerator material 39 during the operation of the Stirling refrigerator even after the operation is stopped. After this, when restarting the operation, the switch 40
By allowing air to flow only to the side of the branch passage 38, the expansion chamber 5 is intentionally cooled by the cold heat accumulated in the regenerator material 39. As a result, the temperature difference between the working gas temperature of the compression chamber 4 and the working gas temperature of the expansion chamber 5 can be intentionally promoted.

In the above-mentioned embodiment, some specific examples have been described as the temperature difference promoting means for promoting the temperature difference between the working gas temperature in the compression chamber and the working gas temperature in the expansion chamber. It is not limited to this. Any means may be used as long as it intentionally promotes the temperature difference between the working gas temperatures in the two chambers from immediately after the start of the operation of the Stirling engine until the steady operation state is reached.
It is also possible to use the specific temperature promoting means shown in the above-mentioned embodiment in combination with each other.

Further, although the heat medium flowing in the flow passage is often air or liquid, it is not particularly limited and any heat medium may be used.

Further, in all of the above embodiments, the Stirling refrigerator, which is an application example of the Stirling engine, has been described as an example, but the present invention is not limited to this.

Therefore, the above-described embodiments disclosed this time are exemplifications in all respects, and are not restrictive. The technical scope of the present invention is defined by the claims, and includes the meaning equivalent to the description of the claims and all modifications within the scope.

[0074]

According to the present invention, during unsteady operation immediately after the start of operation, a thermal load is applied to the reciprocating motion of the piston by promoting the temperature difference between the working gas temperature in the compression chamber and the working gas temperature in the expansion chamber. Therefore, it becomes possible to operate the Stirling engine in a state closer to that during steady operation. As a result, the piston can be driven with a high input voltage immediately after the start of operation, and the collision between the piston and the displacer can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a Stirling refrigerator according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of another example of a Stirling refrigerator in the first embodiment of the present invention.

FIG. 3 is a schematic sectional view of a Stirling refrigerator according to a second embodiment of the present invention.

FIG. 4 is a schematic sectional view of another example of a Stirling refrigerator in the third embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a Stirling refrigerator of still another example according to Embodiment 3 of the present invention.

FIG. 6 is a schematic sectional view of a Stirling refrigerator according to a third embodiment of the present invention.

FIG. 7 is a schematic sectional view of a Stirling refrigerator according to a fourth embodiment of the present invention.

FIG. 8 is a schematic sectional view of a Stirling refrigerator according to a fifth embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view of another example of a Stirling refrigerator in the fifth embodiment of the present invention.

FIG. 10 is a schematic sectional view of a Stirling refrigerator according to a sixth embodiment of the present invention.

FIG. 11 is a schematic sectional view of a Stirling refrigerator of another example in Embodiment 6 of the present invention.

FIG. 12 is a schematic diagram for explaining a configuration of a Stirling refrigerator in a seventh embodiment of the present invention.

FIG. 13 is a schematic diagram for explaining the configuration of a Stirling refrigerator in the eighth embodiment of the present invention.

FIG. 14 is a schematic sectional view of a conventional general Stirling refrigerator.

[Explanation of symbols]

1 cylinder, 2 displacer, 3 piston, 4
Compression chamber, 5 expansion chamber, 6 regenerator, 7 linear motor, 8 displacer rod, 9 spring, 10
High temperature side internal heat exchanger, 11 Heat dissipation part, 12 Low temperature side internal heat exchanger, 13 Cooling part, 14 Back pressure chamber, 15 Main body casing, 17-19 heater, 20 Stirling refrigerator, 21 External heat exchanger, 22 Blower Fan, 23 circulation passage, 24 circulation passage, 25 reserve tank, 26 external cooler, 27 circulation pump, 28 branch passage, 29 heat storage material, 30 switcher, 32 heat storage material, 33 to 35 heater, 36 blower fan, 37 circulation Passage, 38 branch passage, 39 cold storage material, 40 switching device, 42 freezer / refrigerator, 43 external heat exchanger, 44 circulation pump, 45 circulation passage, 46 external heat exchanger, 47 high temperature side temperature detection sensor, 48 low temperature side temperature Detection sensor.

Claims (18)

[Claims] 1. A piston fitted in a cylinder and reciprocating driven by driving means; a displacer fitted in the cylinder reciprocating with a phase difference from the piston; and between the piston and the displacer. A compression chamber partitioned and formed, an expansion chamber located on the opposite side of the compression chamber with the displacer interposed, and a temperature difference promoting means for promoting a temperature difference between the temperature inside the compression chamber and the temperature inside the expansion chamber. A Stirling engine equipped with. 2. A temperature difference detecting means for detecting the temperature difference, and a control means for stopping the operation of the temperature difference promoting means when the temperature difference detected by the temperature difference detecting means reaches a predetermined temperature difference. The Stirling engine according to claim 1, further comprising: 3. The Stirling engine according to claim 1, wherein the temperature difference promoting means is a heating means for heating the compression chamber. 4. The Stirling engine according to claim 3, wherein the heating means comprises a heater disposed inside the compression chamber. 5. The Stirling engine according to claim 3, wherein the heating means comprises a heater arranged outside the compression chamber. 6. A heat radiating section made of a metal material for radiating heat in the compression chamber to the outside, wherein the heating means is a voltage applying means for applying a voltage to the heat radiating section to flow a current. The Stirling engine described in 3. 7. The temperature difference promoting means comprises a heater for heating a back pressure chamber which is located on the opposite side of the compression chamber with the piston interposed therebetween and which communicates with the compression chamber.
Stirling agency described in. 8. The Stirling engine according to claim 1, wherein the temperature difference promoting unit is a heat storage unit that stores heat so that the heat in the compression chamber is not released to the outside. 9. The Stirling engine according to claim 8, wherein the heat storage means is made of a heat storage material arranged outside the compression chamber. 10. The Stirling engine according to claim 8, further comprising a circulation path for circulating a heat medium for exchanging heat between the compression chamber and the outside, wherein the heat storage means is disposed in the circulation path. 11. The Stirling engine according to claim 10, wherein the circulation path includes a branch path, and the heat storage means is disposed in the branch path. 12. The Stirling engine according to claim 1, wherein the temperature difference promoting unit is a cooling unit that cools the expansion chamber. 13. The Stirling engine according to claim 1, wherein the temperature difference promoting unit is a cool storage unit that stores heat so that the heat in the expansion chamber is not transferred to the outside. 14. The Stirling engine according to claim 13, further comprising: a circulation passage through which a heat medium for exchanging heat between the expansion chamber and the outside is circulated, and the cool storage means is disposed in the circulation passage. 15. The Stirling engine according to claim 14, wherein the circulation path includes a branch path, and the cool storage means is disposed in the branch path. 16. A piston fitted in a cylinder and reciprocating driven by a driving means, a displacer reciprocating with a phase difference from the piston, and a compression chamber defined between the piston and the displacer. A method for operating a Stirling engine including an expansion chamber located on the opposite side of the compression chamber with the displacer interposed therebetween, wherein the temperature difference between the compression chamber and the expansion chamber is increased at the start of operation. A method for operating a Stirling engine, wherein the promotion of expansion of the temperature difference is stopped when the temperature difference reaches a predetermined temperature difference. 17. The Stirling engine includes a flow passage through which a heat medium for exchanging heat between the compression chamber and the outside flows,
A flow means for flowing the heat medium in the flow passage is further provided, and the expansion of the temperature difference is promoted by stopping the flow means, and the expansion of the temperature difference is promoted by operating the flow means. The method of operating a Stirling engine according to claim 16, which is stopped. 18. The Stirling engine comprises a flow passage through which a heat medium for exchanging heat between the expansion chamber and the outside flows,
A flow means for flowing the heat medium in the flow passage is further provided, and the expansion of the temperature difference is promoted by stopping the flow means, and the expansion of the temperature difference is promoted by operating the flow means. The method of operating a Stirling engine according to claim 16, which is stopped.