JPH08159586A - Free-piston type vuilleumier cycle engine - Google Patents

Abstract

PURPOSE: To provide a VM engine in which starting and suitable ordinary operation can be realized without necessity of an exciter of a special structure like a linear motor. CONSTITUTION: The predetermined pressure of operating gas to be formed in an intermediate temperature operating space 17 is stored in reservoirs 28, 32, and the pressure gases stored in the reservoirs are used as drive sources at the time of at least starting a VM engine. In this case, a first gas channel 24 for communicating the predetermined position of the space 17 with gas spring chamber 22B in a low temperature displacer 19 is provided, and a highest pressure reservoir 28 formed openable at least the chamber side is provided at the channel 24, and a second gas channel 25 for communicating the predetermined position of the space 17 with the chamber 22B is provided. A lowest pressure reservoir 32 formed openably at least at the chamber side is provided at the channel 25, and further a third gas channel 25 is provided to be variously deformed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a free piston type Wilmier cycle engine (Fre) used for an air conditioner, a refrigerator, etc.
e Piston Vuillermiercycle Machine).

[0002]

2. Description of the Related Art FIG. 2 shows a cross-sectional view of a main part of a conventional free piston type Wilmier cycle engine (hereinafter abbreviated as VM engine), and its structure and operation will be described. The high temperature displacer 1 has a stepped rod in which a rod 2 having a diameter a and a rod 3 having a diameter b are connected in series, and the end portion of the rod 3 is forcibly driven up and down in the figure by a vibrator (not shown). To be done. On the other hand, on the outside of the cylindrical sleeves 4a and 4b, the high temperature side high temperature part heat exchanger 5, the high temperature side regenerator 6,
A high temperature side intermediate temperature part heat exchanger 7, a low temperature side intermediate temperature part heat exchanger 8, a low temperature side regenerator 9 and a low temperature side low temperature part heat exchanger 10 are provided, and a high temperature side intermediate temperature part heat exchanger 7 and a low temperature side intermediate temperature are provided. It is integrated with the partial heat exchanger 8 via a ring-shaped portion 11. Further, outside the high temperature side regenerator 6, the high temperature side intermediate temperature part heat exchanger 7, and the low temperature side intermediate temperature part heat exchanger 8, a high temperature side cylindrical shell 12 and intermediate temperature side cylindrical shells 13a and 13b are arranged,
A low temperature side cylindrical shell 14 is provided outside the low temperature side regenerator 9 and the low temperature side low temperature section heat exchanger 10 to be isolated from the outside.

An electric heater 15 is provided on the head of the high temperature side cylindrical shell 12, and heat is taken out from the high temperature side middle temperature section heat exchanger 7 and the low temperature side middle temperature section heat exchanger 8 for heating, and low temperature for cooling. Cold heat is applied from the low temperature side heat exchanger 10. Water is arranged outside the respective heat exchangers as a carrier medium. A vibrating machine (not shown) is connected to the lower part of the rod 3 and is used for vibrating the high temperature displacer 1 for starting and steady operation. Here, the working gas such as helium in the high temperature working space 16 and the middle temperature working space 17 heated by the electric heater 15 heats the outer water via the high temperature side middle temperature section heat exchanger 7, while the low temperature working space is heated. 1
8 and the working gas in the middle temperature working space 17 heat the outside water via the low temperature side middle temperature part heat exchanger 8 and remove heat from the outside water via the low temperature side low temperature part heat exchanger 10. At this time, the vertical movement of the high-temperature displacer 1 moves the working gas between the high-temperature operating space 16 and the intermediate-temperature operating space 17, and the high-temperature side high-temperature part heat exchanger 5, the high-temperature side regenerator 6 and the high-temperature side intermediate-temperature part heat exchanger Alternate through 7. Also, the low temperature working space 1
8 and a low temperature displacer 1 for separating the medium temperature working space 17
The vertical movement of 9 causes the working gas to alternate between the low temperature operating space 18 and the intermediate temperature operating space 17 through the low temperature side low temperature section heat exchanger 10, the low temperature side regenerator 9 and the low temperature side intermediate temperature section heat exchanger 8. At that time, pressure change occurs due to a change in the ratio of the high temperature working gas and the low temperature working gas.
9 is applied to the low temperature displacer 19 so as to maintain a certain phase difference with the high temperature displacer 1.
Works. At this time, the temperature of each operating space is kept constant by the heat storage action of each regenerator 6 and 9. The output of the VM engine is used to release and absorb the heat of the heat exchangers 5, 7, 8 and 10 for heating and cooling.

The technical literature on VM engines is "Devel
opment of a Fre Piston Vuilleumier Machine for
There are "Cooling Purposes" (ISCE-91060 P.15) and "Basic research on free-piston type Wilmier cycle heat pump" by the present inventor (announced at the 71st Ordinary General Meeting of the Japan Society of Mechanical Engineers). The former introduces a testing machine having the same structure as the VM engine to which the present invention is applied, and the latter introduces a VM heat pump developed by the authors.

[0005]

In the conventional structure as described above, some type of vibration exciter, for example, at the tip of the rod 3 shown in FIG.
It is necessary to connect a linear motor. Therefore, VM
There is a problem that the length (height) of the engine becomes long and the price becomes expensive. Furthermore, the vibration state of the low temperature displacer could not be controlled externally. The present invention solves the above-mentioned problems (problems) of the conventional one, and by utilizing the characteristics of the VM engine, it is possible to realize start-up and proper steady operation without the need for a vibrator having a special structure such as the conventional linear motor. Free piston type Wilmie cycle engine (VM engine)
The purpose is to provide.

[0006]

In order to solve the above-mentioned problems, a VM engine according to the present invention is provided with a medium temperature working space formed between a high-temperature displacer and a low-temperature displacer, along with the operation of the VM engine. A predetermined pressure of the working gas formed is stored in the reservoir, and the pressure gas stored in the reservoir is used as a drive source at least when the VM engine is started. That is, there is provided a first gas flow passage that connects the medium temperature operating space position and the gas spring chamber in the low temperature displacer, and at least the gas spring chamber side is formed in the first gas flow passage so as to open and close the maximum pressure reservoir. Formed. In addition, a second gas flow passage that connects the medium temperature operating space position and the gas spring chamber is provided, and a minimum pressure reservoir in which at least the gas spring chamber side is openable and closable is formed in this second gas flow passage. good. Further, it is desirable to have both a maximum pressure reservoir and a minimum pressure reservoir in the VM engine. Further, a third gas flow passage having a resistance equal to or higher than a predetermined value is provided to connect the medium temperature operating space position and the gas spring chamber, and an opening / closing valve is formed in the third gas flow passage.
The VM engine is provided with the above-mentioned maximum pressure reservoir and / or minimum pressure reservoir, and is also provided with a first or second gas flow passage and a third gas flow passage which communicate the medium temperature operating space position with the gas spring chamber. Or, first, second and third
It is more desirable to provide each of the gas flow passages, and to form an opening / closing valve in each of the gas flow passages. The above-mentioned maximum pressure reservoir is formed by a check valve and a gas tank having a predetermined volume, which are connected to the first gas passage in a direction in which the gas flows from the medium temperature working space toward the gas spring chamber. It is desirable to provide an opening / closing valve on at least the gas spring chamber side of the reservoir. Further, the minimum pressure reservoir is formed by a check valve and a gas tank having a predetermined volume, which are connected to the second gas passage in a direction in which gas flows from the gas spring chamber toward the medium temperature working space. It is desirable to provide an opening / closing valve at least on the gas spring chamber side of the lowest pressure reservoir.

[0007]

In the VM engine according to the present invention, the medium pressure working space formed between the high temperature displacer and the low temperature displacer as described above is used to store the predetermined pressure of the working gas formed as the VM engine is operated in the reservoir. The pressure gas accumulated and used in the reservoir is used as a drive source at least at the time of starting the VM engine, thereby eliminating the need for a drive function facility used at the time of starting. That is, by providing the first gas flow path forming the highest pressure reservoir, the VM engine can be started without the driving function by the high pressure gas accumulated in the highest pressure reservoir. Similarly, the VM engine can be started without a driving function by providing the second gas flow path forming the lowest pressure reservoir. When both the highest pressure reservoir and the lowest pressure reservoir are provided, the cold displacer is given a driving force in both directions, so that it can be started more easily. Further, when the third gas passage is provided so as to be openable and closable, the pressure difference between the medium temperature operating space and the gas spring chamber can be adjusted, so that the output of the VM engine can be easily adjusted.
Further, when the first gas flow path forming the highest pressure reservoir and / or the second gas flow path forming the lowest pressure reservoir and the third gas flow path formed to be openable / closable as described above are provided, controllability is improved. A good VM engine can be compactly constructed.
The highest pressure reservoir consisting of a gas tank with a certain volume is connected to the gas flow path formed between the medium temperature working space and the gas spring chamber in the direction of gas flow from the medium temperature working space to the gas spring chamber. In cooperation with the valve, it acts as its highest pressure reservoir. Further, the lowest pressure reservoir composed of a gas tank having a predetermined volume is connected to a gas passage formed between the medium temperature operating space and the gas spring chamber in a direction in which gas flows from the gas spring chamber toward the medium temperature operating space. Functions as a minimum pressure reservoir in cooperation with the check valve. Further, by providing an opening / closing valve on each gas spring chamber side of the maximum pressure reservoir and the minimum pressure reservoir, the opening / closing valve is operated (controlled) at a necessary time such as when the VM engine is started to control the maximum pressure reservoir and the maximum pressure reservoir. The VM engine is started by the pressure gas accumulated in the lowest pressure reservoir, and during steady operation, the gas spring chamber in the low temperature displacer is properly connected to the highest pressure reservoir or the lowest pressure reservoir to ensure high and low temperatures. The vibration state of the displacer can be controlled externally.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to one embodiment shown in the drawings. FIG. 1 is a vertical sectional front view including a control flow path showing an embodiment of the present invention. In FIG. 1, the same reference numerals as those in FIG. Detailed description is omitted. In FIG. 1, the lower end of the rod 3 is fixed to the ceiling surface of the buffer chamber 20 by a high temperature displacer mechanical spring 21 inside the buffer chamber 20. A first gas spring chamber 22A is formed between the buffer chamber 20 and the low temperature side cylindrical shell 14. A second gas spring chamber 22B is provided in the low-temperature displacer, and the first gas spring chamber 22A and the second gas spring chamber 22B communicate with each other through a gas flow passage 22C formed inside the rod 3 to form an integrated gas spring chamber. Is formed. Second gas spring chamber 22B
Inside, a mechanical spring 23 for a low temperature displacer is mounted between the rod 2 and the ceiling of the second gas spring chamber 22B.

Three gas passages 24, 25 and 26 are provided between a predetermined position of the medium temperature operating space 17 and the first gas spring chamber 22A. A check valve 27 is inserted in the first gas flow path 24 in a direction in which the working gas flows from the intermediate temperature working space 17 toward the first gas spring chamber 22A, and the capacity and pressure resistance structure satisfy the functions described later. The maximum pressure reservoir 28 composed of a gas tank of
The on-off valves 29 and 30 are inserted into the gas flow paths 24 on both sides of the above. In the second gas flow path 25, the first gas spring chamber 22
The check valve 31 is inserted in the direction in which the working gas flows from A to the medium temperature working space 17, and the minimum pressure reservoir 32 composed of a gas tank having a capacity and pressure resistance structure that satisfies the function described later is provided. The opening / closing valves 33 and 34 are inserted into the flow path 25, respectively. Third gas flow path 26
An on-off valve 35 is inserted in the. These on-off valves 3
Desirably, each of 3, 34 and 35 enables remote (operation) control. Further, as the opening / closing valve 35, an electromagnetic valve having a flow rate adjusting function or the like is used, or the gas flow path 2
By means such as inserting a throttle valve (not shown) in FIG. 6, the flow rate of the working gas flowing through the third gas flow passage 26 when the on-off valve 35 is opened is adjusted according to the required performance of the target VM engine as will be described later. It is desirable to have a controllable means.

Next, the highest pressure reservoir 28, the lowest pressure reservoir 32, and the third gas flow path 2 in the above-mentioned configuration.
The function of 6 will be explained. When this VM engine is assembled and a predetermined working gas is filled, the opening / closing valves 29 and 30 are closed to store the working gas having a predetermined pressure in the maximum pressure reservoir 28. Similarly, the on-off valves 33 and 34 are closed to store the working gas having a predetermined pressure in the lowest pressure reservoir 32.

When the opening / closing valve 30 is opened while the opening / closing valve 29 is closed by the control device (not shown) at the time of starting the VM engine, the high pressure gas in the maximum pressure reservoir 28 is higher than the maximum pressure value in the intermediate temperature working space 17. It is supplied to the gas spring chamber 22B in the low temperature displacer 19 which has become low, via the first gas spring chamber 22A. Therefore, the gas spring chamber 22
The low temperature displacer 19 is generated by the gas spring force generated in B.
Operate. After that, when the opening / closing valve 30 is closed at a predetermined timing by a control device (not shown), the low temperature displacer 1 is operated by the internal configuration of the VM engine and the function thereof.
The movement of 9 moves in the original direction even if it is reversed. When the opening / closing valve 30 is opened again by the control device, the low temperature displacer 19 is activated again. This action continues until the on-off valve 30 is shut off or the pressure of the working gas in the maximum pressure reservoir 28 becomes equal to the pressure value in the gas spring chamber. Therefore, the low temperature displacer 19 is vibrated and the VM
The engine can be started smoothly. In addition, the V started in this way
In the operation cycle of the M engine, it is necessary to open the on-off valve 29 at an appropriate timing by the control device (not shown) during operation of the VM engine to open and close the on-off valve 30 so as to increase the minimum pressure in the gas spring chamber 22B. And the maximum pressure reservoir 28 is supplied with gas from the working space side, so that the maximum pressure is maintained.

When the on-off valve 33 is opened by the control device while the on-off valve 34 is closed by the control device at the time of start-up, the low pressure gas in the minimum pressure reservoir 32 is lower than the minimum pressure value in the intermediate temperature working space 17. It is supplied to the gas spring chamber 22B in the low temperature displacer 19, which has become higher, via the first gas spring chamber 22A. Therefore, the low temperature displacer 19 is operated by the gas spring force. After that, the control device controls the opening / closing valve 33 at a predetermined timing
When is closed, the movement of the low temperature displacer 19 is reversed due to the internal structure of the VM engine and the function thereof, and the low temperature displacer 19 moves in the original direction. When the opening / closing valve 33 is opened again by the control device, the low temperature displacer 19 is activated again. This action continues until the on-off valve 33 is shut off or the pressure of the working gas in the lowest pressure reservoir 32 becomes equal to the pressure value in the gas spring chamber. Therefore, the low temperature displacer 19 can be vibrated to smoothly start the VM engine. In the operation cycle of the VM engine started in this way,
When the above-mentioned control device opens the on-off valve 34 at an appropriate timing during operation of the VM engine to open and close the on-off valve 33 so as to lower the maximum pressure in the gas spring chamber 22B, the required operation cycle can be adjusted and At this time, gas is released from the lowest pressure reservoir 32 to the working space side, so that the lowest pressure is maintained.

Corresponding to the position of the high temperature displacer 1,
An on-off valve 30 connected to the highest pressure reservoir 28 and an on-off valve 3 connected to the lowest pressure reservoir 32 by the control device described above.
The low temperature displacer 19 is vibrated by alternately opening and closing 3 at appropriate timing, and the VM engine can be started more easily than the above.

After the VM engine is started, when the opening / closing valve 29 is opened and the opening / closing valve 30 is closed by the control device (not shown), the gas pressure in the intermediate temperature working space 17 is the maximum pressure reservoir 28.
When it becomes higher than the internal gas pressure, the working gas in the intermediate temperature working space 17 flows into the maximum pressure reservoir 28 via the check valve 27. On the contrary, when the gas pressure in the medium temperature working space 17 becomes lower than the gas pressure in the maximum pressure reservoir 28, the check valve 27
The working gas does not flow to either side. Therefore,
The working gas is accumulated in the highest pressure reservoir 28 at the highest gas pressure generated in the medium temperature working space 17. A pressure sensor (not shown) may be provided in the maximum pressure reservoir 28, and when the measured value of the pressure sensor reaches a predetermined value, the opening / closing valve 29 that has been opened by the operation of the control device may be closed. Since the working gas having a pressure equal to or higher than the predetermined pressure is accumulated in the maximum pressure reservoir 28, the working gas can be used as described above at the next start or the like.

After the VM engine is started, if the on-off valve 34 is opened and the on-off valve 33 is closed by the above-mentioned control device, if the gas pressure in the intermediate temperature working space 17 becomes lower than the gas pressure in the minimum pressure reservoir 32, the reverse occurs. The working gas accumulated in the lowest pressure reservoir 32 via the stop valve 31 is stored in the medium temperature working space 17
Flows into. On the contrary, when the gas pressure in the medium temperature working space 17 becomes higher than the gas pressure in the minimum pressure reservoir 32, the check valve 31 serves to prevent the working gas from flowing to either side. Therefore, the working gas is accumulated in the lowest pressure reservoir 32 at the lowest gas pressure generated in the medium temperature working space 17. In this case as well, a pressure sensor (not shown) is provided in the lowest pressure reservoir 32, and when the measured value of this pressure sensor reaches a predetermined value, the opening / closing valve 34 that has been opened by the above-mentioned control device may be closed. . Since the working gas having a pressure equal to or lower than the predetermined pressure is accumulated in the lowest pressure reservoir 32, the working gas can be used as described above at the next start or the like.

When the opening / closing valve 35 is opened by the control device while the VM engine is started and is in operation, a gas passage is formed between the intermediate temperature working space 17 and the first gas spring chamber 22A,
The working gas flows from the higher gas pressure direction to the lower gas pressure direction at a flow rate corresponding to this pressure difference and the resistance value of the gas flow path 26. Therefore, since the deviation between the gas pressure in the medium temperature working space 17 and the gas pressure in the second gas spring chamber 22B in the low temperature displacer 19 communicating with the first gas spring chamber 22A is reduced, this VM engine The output is reduced. Further, by operating the on-off valve 35, as described above, the maximum pressure reservoir 2
8 or the pressure difference between the gas pressure in the second gas spring chamber 22B in the low temperature displacer 19 and the gas pressure in the intermediate temperature working space 17, which is forcibly changed by the pressure gas from the lowest pressure reservoir 32, is the optimum value. Adjust so that
That is, the opening / closing valve 35 is appropriately opened / closed by a control device (not shown) in accordance with the load condition of the VM engine or the like.
Control using an on-off valve with a flow control function
The output of the VM engine can be appropriately controlled by means such as inserting and controlling a flow rate control valve in the third gas passage 26. In addition, even if the throttle valve is inserted in the third gas flow path 26 and the pressure difference between the medium temperature working space and the low temperature displacer becomes large, an excessive flow rate is prevented from causing a sudden decrease in the output of the VM engine. can do. That is, an appropriate and economical flow rate control function may be provided depending on the operating condition and the required performance of this VM engine.

The above-mentioned embodiment shows an example for realizing the technical idea of the present invention, and it is needless to say that it may be appropriately applied and modified according to the constitution of the VM engine and its use. . For example, the highest pressure reservoir, the lowest pressure reservoir, and the like may be provided outside the conventional VM engine body by forming a gas flow path by piping, or may be integrated with the VM engine body. Further, although it is desirable to provide both the highest pressure reservoir and the lowest pressure reservoir as shown in FIG. 1, only one of them may be provided. Further, the above-mentioned third gas flow path 26 may be provided independently, or may be provided in parallel with the highest pressure reservoir or the lowest pressure reservoir or the highest pressure reservoir and the lowest pressure reservoir. Further, although the lowest pressure reservoir and the highest pressure reservoir are explained as being constituted by the gas tanks connected via the check valve, the gas having the necessary capacity and the gas required as desired depending on the configuration of any other gas flow passage is also provided. Of course, it is only necessary to obtain pressure. Also, for each on-off valve, it is sufficient to select an appropriate model corresponding to the required function / performance of the VM engine and the function of the control device.
The on-off valves 29 and 34 may be removed depending on the conditions of this VM engine.

[0018]

Since the free piston type Wilmie cycle engine (VM engine) according to the present invention is constructed and operates as described above, it has the following excellent effects. A predetermined pressure of the working gas formed by the operation of the free piston type Wilmie cycle engine is accumulated in the medium temperature working space in the reservoir, and the pressure gas accumulated in the reservoir is used as a drive source at least at the time of starting. This eliminates the need for equipment with a special drive function such as a linear motor having a special structure. By forming the highest pressure reservoir, the VM engine can be started without a drive function by the high pressure gas stored in the highest pressure reservoir. In addition, heat cycle operation control can be enabled. By forming the lowest pressure reservoir, the VM engine can likewise be started without a drive function.
In addition, heat cycle operation control can be enabled. When both the maximum pressure reservoir and the minimum pressure reservoir are provided, it is possible to more easily start the engine and control the operation of the heat cycle. By providing a gas flow path provided with an on-off valve, output adjustment of this VM engine can be easily realized.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional front view of a free piston type Wilmie cycle engine including a control flow path according to an embodiment of the present invention.

FIG. 2 is a vertical sectional front view of a conventional free piston type Wilmie cycle engine.

[Explanation of symbols]

 1: High temperature displacer 5: High temperature side high temperature part heat exchanger 6: High temperature side regenerator 7: High temperature side middle temperature part heat exchanger 8: Low temperature side middle temperature part heat exchanger 9: Low temperature side regenerator 10: Low temperature side low temperature part heat Exchanger 12: High temperature side cylindrical shell 13a, 13b: Medium temperature side cylindrical shell 14: Low temperature side cylindrical shell 16: High temperature operating space 17: Medium temperature operating space 18: Low temperature operating space 19: Low temperature displacer 20: Buffer chamber 22A, 22B: Gas spring chamber 22C: Gas flow path 24, 25, 26: Gas flow path 27, 31: Check valve 28: Maximum pressure reservoir 29, 30, 33, 34, 35: Open / close valve 32: Minimum pressure reservoir

Claims (8)

[Claims] 1. A high temperature side high temperature part heat exchanger, a high temperature side regenerator,
In a free-piston type Wilmier cycle engine having a high temperature side medium temperature section heat exchanger, a low temperature side medium temperature section heat exchanger, a low temperature side regenerator and a low temperature side low temperature section heat exchanger, and further having a high temperature displacer and a low temperature displacer, The medium pressure working space formed between the high-temperature displacer and the low-temperature displacer accumulates a predetermined pressure of working gas formed with the operation of the free piston type Wilmier cycle engine in a reservoir, and the pressure accumulated in the reservoir. A free piston type Wilmie cycle engine, characterized in that gas is configured to be used as a drive source at least when the free piston type Wilmie cycle engine is started. 2. A high temperature side high temperature part heat exchanger, a high temperature side regenerator,
In a free-piston type Wilmier cycle engine having a high temperature side medium temperature section heat exchanger, a low temperature side medium temperature section heat exchanger, a low temperature side regenerator and a low temperature side low temperature section heat exchanger, and further having a high temperature displacer and a low temperature displacer, A first gas flow passage is provided which communicates a medium temperature operating space position formed between the high temperature displacer and the low temperature displacer with a gas spring chamber formed in the low temperature displacer, and at least the first gas flow passage is provided in the first gas flow passage. The free piston type Wilmie cycle engine according to claim 1, wherein a maximum pressure reservoir is formed so that the gas spring chamber side can be opened and closed. 3. A high temperature side high temperature part heat exchanger, a high temperature side regenerator,
In a free-piston type Wilmier cycle engine having a high temperature side medium temperature section heat exchanger, a low temperature side medium temperature section heat exchanger, a low temperature side regenerator and a low temperature side low temperature section heat exchanger, and further having a high temperature displacer and a low temperature displacer, A second gas passage is provided to connect the medium temperature operating space position formed between the high temperature displacer and the low temperature displacer to the gas spring chamber formed in the low temperature displacer, and at least the second gas passage is provided in the second gas passage. The free piston type Wilmier cycle engine according to claim 1, wherein a minimum pressure reservoir is formed such that the gas spring chamber side is openable and closable. 4. A high temperature side high temperature part heat exchanger, a high temperature side regenerator,
In a free-piston type Wilmier cycle engine having a high temperature side medium temperature section heat exchanger, a low temperature side medium temperature section heat exchanger, a low temperature side regenerator and a low temperature side low temperature section heat exchanger, and further having a high temperature displacer and a low temperature displacer, First and second gas flow paths are provided to connect the medium temperature operating space position formed between the high temperature displacer and the low temperature displacer to the gas spring chamber formed in the low temperature displacer, and the first gas is provided. At least the gas spring chamber side is formed in the flow passage so as to be openable and closable to form a maximum pressure reservoir, and at least the gas spring chamber side is formed in the second gas flow passage so as to be openable and closable to form a minimum pressure reservoir. The free piston type Wilmie cycle engine according to claim 1. 5. A high temperature side high temperature part heat exchanger, a high temperature side regenerator,
In a free-piston type Wilmier cycle engine having a high temperature side medium temperature section heat exchanger, a low temperature side medium temperature section heat exchanger, a low temperature side regenerator and a low temperature side low temperature section heat exchanger, and further having a high temperature displacer and a low temperature displacer, A third gas passage is provided to connect the medium temperature operating space position formed between the high temperature displacer and the low temperature displacer to the gas spring chamber formed in the low temperature displacer, and the third gas passage is provided in this third gas passage. A free-piston Wilmie cycle engine characterized by having an on-off valve. 6. A medium temperature working space position and a low temperature displacer formed between the high temperature displacer and the low temperature displacer of a free piston type Wilmie cycle engine provided with the highest pressure reservoir and / or the lowest pressure reservoir. A first gas passage or a second gas passage communicating with the gas spring chamber, and the third gas passage, or
Alternatively, the first, second and third gas flow passages are provided, and an opening / closing valve is formed in each of the gas flow passages. The free piston type Wilmier cycle according to claim 1. organ. 7. The highest pressure reservoir operates in cooperation with a check valve which has a predetermined performance in the gas flow path and is coupled in a direction in which gas flows from the medium temperature operating space toward the gas spring chamber, The free piston type Wilmier cycle engine according to any one of claims 1, 2 or 4 or 6, wherein an opening / closing valve is provided at least on the gas spring chamber side of the highest pressure reservoir. 8. The minimum pressure reservoir operates in cooperation with a check valve which has a predetermined performance in the gas flow path and is connected in a direction in which gas flows from the gas spring chamber side toward the medium temperature operating space. 7. The free piston type Wilmier cycle engine according to claim 1, 3 or 4 or 6, wherein an opening / closing valve is provided at least on the gas spring chamber side of the lowest pressure reservoir.