JPH0330715B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a control valve that controls the pressure in each working space of a Stirling engine so as to maintain equilibrium. It is used in multi-cylinder double-acting Stirling engines, etc., which require balance of maximum cycle pressure.

(Prior art) As a conventional device of this type, Japanese Patent Application Laid-Open No. 57-83647
There is something shown in the publication No. In this conventional pressure balancing device, the cycle maximum pressure of each working space is guided to each cylinder 60, as shown in FIG. When the maximum pressure in at least one working space changes and the equilibrium is disrupted, the spring 61
The sliding member 62 slides due to the urging force of the discharge hole 6.
3, high pressure gas is released to the low pressure circuit side to maintain pressure balance.

(Problems to be Solved by the Invention) In the conventional device described above, the number of pressure adjustment mechanisms such as cylinders, springs, and sliding members is required to be the same as the number of working spaces of the Stirling engine. The problem was that it became complicated. In addition, in the above device, even if there is a small cycle maximum pressure difference between cylinders that does not interfere with engine operation, if it occurs, the working space is always the lowest among the cycle maximum pressures of all working spaces. control to match the pressure. Therefore, there was a problem that a large amount of gas and heat leaked through the discharge hole, resulting in a decrease in engine performance.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a pressure equalization device that has a simple, inexpensive structure, automatically adjusts, and minimizes leakage of gas and heat. purpose.

[Structure of the Invention] (Means for Solving the Problems) The control valve of the present invention is connected to each working space of a multi-cylinder Stirling engine through a check valve from which working gas exits, and all A high-pressure cylinder chamber connected to the highest pressure pipe where the highest pressure in the space becomes the pipe internal pressure, and a high-pressure cylinder chamber connected to each working space via a check valve that allows working gas to enter the working space, a housing having a low-pressure cylinder chamber connected to a minimum pressure pipe whose minimum pressure is the internal pressure of the pipe, a bypass passage communicating with the highest pressure pipe and the minimum pressure pipe, and a high-pressure piston that slides within the high-pressure cylinder chamber. and a low-pressure piston part that slides within the low-pressure cylinder chamber, and moves in the forward and reverse directions within the housing by the relative pressure received by the high-pressure piston part and the low-pressure piston part, and the full push pressure received by the high-pressure piston part. The invention is characterized by comprising a valve that opens the bypass passage when the force is greater than the total pushing force exerted by the low-pressure piston portion, and closes the bypass passage in the opposite case.

The control valve of the present invention is comprised of a housing and a valve disposed within the housing.

The housing is provided with a high pressure cylinder chamber and a low pressure cylinder chamber. A maximum pressure pipe in which the maximum pressure in each working space of the multi-cylinder Stirling engine is the internal pressure is connected to this high pressure cylinder chamber. This highest pressure pipe communicates with each working space via a check valve that opens only in the direction in which working gas exits from each working space. Therefore, the pressure in the highest pressure pipe becomes the highest pressure in each working space. Note that there is no particular restriction on the number of working spaces that communicate with the highest pressure pipe, and it is possible to make a single highest pressure pipe communicate with a large number of working spaces.

A minimum pressure pipe in which the minimum pressure in each working space of the multi-cylinder Stirling engine is the internal pressure is connected to the low pressure cylinder chamber. This minimum pressure pipe communicates with each working space via a check valve that opens only in the direction in which working gas enters each working space. The minimum pressure line can also communicate with a working gas reservoir.

The housing is provided with a bypass passage that communicates the highest pressure pipe and the lowest pressure pipe. This bypass passage makes it possible to release excess pressure when the pressure balance of the engine is disrupted.

The valve includes a high-pressure piston section that slides in the high-pressure cylinder chamber and a low-pressure piston section that slides in the low-pressure cylinder chamber. Each piston portion may be separate or integrally formed. The high-pressure piston section is urged in one direction by the maximum pressure led from the maximum pressure pipe, and the low-pressure piston section is urged in the opposite direction to the urging force of the high-pressure piston section by the minimum pressure led from the minimum pressure pipe. The biasing force from both directions causes the valve to move in the forward and reverse directions, making it possible to open and close the bypass passage. However, if this continues, the urging force applied to the high-pressure piston portion will exceed the urging force applied to the low-pressure piston portion, and the valve will move in only one direction. Therefore, it is necessary to increase the biasing force that the low pressure piston part receives by some means. As a means of this,
For example, the biasing force of a spring can be used. In addition, by making the area of the part of the high-pressure piston part that receives the maximum pressure urging force smaller than the area of the part of the low-pressure piston part that receives the minimum pressure urging force,
It is also possible to balance the total stress in the high pressure piston section with the total stress in the low pressure piston section. According to this means, the ratio of the maximum pressure to the minimum pressure of the engine, which is known in advance, is set as the area ratio of each piston part,
As long as the pressure ratio is not exceeded, the balance passage can be kept closed. Therefore, leakage of gas and heat through the bypass passage can be minimized, and it is possible to maintain pressure balance in most engines simply by changing the area ratio of the piston portion.

When employing the above means for changing the area ratio of each piston portion, it is desirable that the valve be an integrally formed two-stage piston with a stepped cross section. It is also possible to provide a groove or the like on the valve surface so that when the pressure ratio exceeds a predetermined value and the valve moves, the bypass passage of the housing coincides with the groove and opens the bypass passage. In this case, it is desirable that a constant pressure be maintained between the shoulder of the valve and the housing so that negative pressure does not impede movement of the valve. For example, it may be released to the atmosphere, but if there is a leak of working gas, it is desirable to connect it to a working gas storage chamber or the like that is adjusted so that the pressure will not change even if the working gas moves.

(Function) In the control valve of the present invention, the maximum pressure and minimum pressure in each working space of the multi-cylinder Stirling engine are applied to the high-pressure piston portion and the low-pressure piston portion of the valve. When the ratio of the highest pressure to the lowest pressure exceeds a predetermined value, the valve moves within the housing to open the bypass passage and allow the working gas in the highest pressure tube to escape into the lowest pressure tube. When the ratio of the maximum pressure to the minimum pressure becomes less than or equal to a predetermined value, the valve moves to its original position and the bypass passage becomes closed.

(Example) This will be explained in detail below using examples.

FIG. 1 shows a system diagram of a multi-cylinder Stirling engine using a control valve according to an embodiment of the present invention.

Inside the cylinder chambers 1a to 1d of the Stirling engine, pistons 2a to 2d are connected with a phase difference by a crank (not shown) via rods 3a to 3d. The space inside the cylinder is divided by seal members 4a to 4d provided on the piston into expansion spaces 5a to 5d having a high temperature and compression spaces 6a to 6d having a low temperature.
a to 6d are heaters 7a to 7d and heat storage units 8a to 8
d and connected via coolers 9a to 9d,
Each constitutes a working space. A working gas made of helium is sealed in this working space and heated by burners 22a to 22d and heaters 7a to 7d. A main pipe 1 is provided in the compression spaces 6a to 6d.
0a to 10d are connected to the reservoir 16 via first check valves 11a to 11d, which open only in the direction of the compression spaces 6a to 6d, the supply conduit 14 and the supply valve 15. The pressure within the supply conduit 14 is then adjusted to the minimum pressure in each working space. Similarly, the main pipes 10a to 10d are connected to the reservoir 16 via second check valves 12a to 12d, which open only in the opposite direction to the compression spaces 6a to 6d, a recovery pipe 17, a pressure reducing valve 18, and a compressor 19. connected. Furthermore, the main pipes 10a to 10d are compressed spaces 6a.
- Third check valve 13 that opens only in the opposite direction to 6d
a to 13d, conduits 20a to 20d and conduit 23
It is connected to the control valve 30 via. conduit 20
a to 20d are all connected to the conduit 23. The control valve 30 is also connected to the supply conduit 14 by an auxiliary conduit 21.

As shown in FIG. 2, the control valve 30 is comprised of a housing 40 and a valve 50 that moves in the axial direction within the housing 40.

A conduit 23 is connected to one end of the housing 40, and an auxiliary conduit 21 is connected to the other end, each of which communicates with the internal space. Also, on the side of the housing 40, a highest pressure bypass port 4 communicating with the internal space is provided.
1 and a minimum pressure bypass port 42,
They communicate with the conduit 23 and the auxiliary conduit 21, respectively.

The valve 50 is composed of a stepped piston in which the area S1 of one end surface 51 is smaller than the area S2 of the other end surface 52, and a ring-shaped gas seal is installed in the internal space of the housing 40, which has an inner diameter that is approximately the same as the diameter of each end surface. They are disposed so as to be airtightly movable in both forward and reverse axial directions via 53a to 53d. The high pressure cylinder chamber 4 is connected to the one end surface 51 and the inner surface of the housing 40.
3, a low pressure cylinder chamber 44 is formed by the other end surface 52 and the inner surface of the housing 40. Note that the ratio R1 (R1=S1/S2) of the area S1 of one end surface 51 and the area S2 of the other end surface 52 of the valve 50 is the normal ratio R2 (R2=
= P1/P2).

A bypass passage 54 is provided on the side peripheral surface of the valve 50, and when the valve 50 moves, the other end surface 52 is connected to the housing 4.
0, the bypass port 41 and the bypass port 42 are configured to communicate with each other via the bypass passage 54 when the bypass port 41 and the bypass port 42 contact the inner wall.

Further, a passage 56 leading to a working gas storage chamber (not shown) is opened in the space 45 formed by the shoulder 55 of the valve 50 and the housing 40, so that the space 45 is always kept at atmospheric pressure and the valve 50 can be easily moved. It is becoming.

The operation of the control valve 30 configured as described above will be explained below. Let us assume that the sealing performance of the sealing member 4a of the piston portion 2a deteriorates.

When working gas leaks from the expansion space 5a to the compression space 6a, the compression space 6a, cooler 9a, and heat storage 8
The cycle pressure of the working space formed by the heater 7a and the expansion space 5b is higher than the cycle pressure of the other three working spaces. The pressure is then formed in the high pressure cylinder chamber 43 through the third check valve 13a, the conduit 20a and the conduit 23. Under normal conditions, the total pushing force applied to the other end surface 52 exceeds the total pushing force applied to the one end surface 51, and the valve 50 is stopped at a position where the shoulder portion 55 abuts the inner surface of the housing 40. Note that at this time, the bypass ports 41 and 42 are not communicating with each other. When the pressure in the high pressure cylinder chamber 43 rises and the ratio R between the pressure in the low pressure cylinder chamber and the pressure in the high pressure cylinder chamber exceeds the above ratio R1, the valve 5
0 begins to move and reaches a position where the other end 52 is in contact with the inner surface of the housing 40. At this position, the bypass port 41 and the bypass port 42 are connected to the bypass passage 5.
4, the high pressure working gas in conduit 20a escapes via auxiliary conduit 21 to supply conduit 14. Further, since the pressure in the working space associated with the expansion space 5a decreases due to leakage of working gas, working gas is supplied from the supply conduit 14 via the first check valve 11d. When the pressure ratio R becomes smaller than R1, the valve 50 returns to its original position and the bypass ports 41 and 42 are closed. Therefore, the cycle maximum pressure and cycle minimum pressure of each working space are kept approximately equal, the output of each working space can be made approximately equal, and the generation of vibration and noise can be prevented.

[Effects of the Invention] As another means for achieving the same purpose, it is also conceivable to provide a needle valve between the highest pressure circuit and the lowest pressure circuit and manually operate the needle valve. However, this method requires complicated operations such as the need to monitor the pressure state. It is also conceivable to use an electromagnetic valve instead of a needle valve, and to automatically open and close the valve by outputting a signal through a pressure transducer for the maximum pressure and the minimum pressure. However, this requires a pressure transducer, a dynamic strain gauge, a controller, etc., and is expensive.

According to the control valve of the present invention, pressure balance can be automatically maintained even in a multi-cylinder Stirling engine by using only one control valve. This reduces the number of parts, simplifies the device, and saves space. Furthermore, since the working gas is released only when a pressure abnormality occurs, leakage of gas and heat can be minimized. Therefore, the cycle pressures in each working space are balanced with minimal loss, and the outputs of each working space can be made approximately equal, which has a great effect in preventing the generation of vibration and noise.

[Brief explanation of the drawing]

1 and 2 relate to a control valve according to an embodiment of the present invention, FIG. 1 is a system diagram of a multi-cylinder Stirling engine using the control valve, and FIG. 2 is a sectional view of the control valve. FIG. 3 is a schematic diagram of a conventional pressure equalization device. 1a to 1d...Cylinder, 2a to 2d...Piston, 30...Control valve, 40...Housing, 41, 4
2...Bypass port, 43...High pressure cylinder chamber, 4
4...Low pressure cylinder chamber, 50...Valve, 53a to 53d
...Gas seal. 54...Bypass passage.

Claims (1)

[Scope of Claims] 1. A maximum pressure pipe connected to each working space of the multi-cylinder Stirling engine through a check valve through which working gas is discharged, and the highest pressure in all the working spaces becomes the pipe internal pressure. A high-pressure cylinder chamber connected to the working space is connected to each working space via a check valve that allows working gas to enter the working space, and connected to a minimum pressure pipe where the minimum pressure in all the working spaces becomes the pipe internal pressure. a housing having a low-pressure cylinder chamber and a bypass passage communicating with the highest-pressure pipe and the lowest-pressure pipe; a high-pressure piston portion that slides within the high-pressure cylinder chamber; and a low-pressure piston portion that slides within the low-pressure cylinder chamber. and moves in the forward and reverse directions within the housing due to the relative pressures received by the high-pressure piston section and the low-pressure piston section, and the total pushing force received by the high-pressure piston section is greater than the total pushing force received by the low-pressure piston section. 1. A control valve for a multi-cylinder Stirling engine, comprising a valve that opens the bypass passage when the case is moved, and closes the bypass passage when the movement is reversed. 2. The high-pressure piston section and the low-pressure piston section slide on the same axis, and the ratio of the area of the end surface on which the pushing force of the high-pressure piston section is applied and the area of the end surface on which the pushing force of the low-pressure piston section is applied is the same for each normal operation. The control valve for a multi-cylinder Stirling engine according to claim 1, wherein the control valve is configured to be slightly smaller than the ratio between the minimum pressure and the maximum pressure in the space. 3. The control valve for a multi-cylinder Stirling engine according to claim 1, wherein the valve is a stepped piston with a stepped cross section in which a low-pressure piston portion and a high-pressure piston portion are integrally formed. 4. The control valve for a multi-cylinder Stirling engine according to claim 3, wherein the space formed by the shoulder of the valve having a stepped cross section and the inner surface of the housing communicates with a working gas storage chamber.