JPS60224958A - Stirling engine - Google Patents

Abstract

PURPOSE:To eliminate conventional piston thus to improve the thermal efficiency and the reliability by encapsulating the working fluid in an enclosed container and providing a heater and a cooler while separating the inner space of said container into two through a partitioner having a communicating hole. CONSTITUTION:Upon lifting of a displacer 21, the pressure in the expansion space 22 will go higher than that in the compression space and the differential pressure will cause motion of the working fluid in the expansion space 22 through a heater 24, a regenerator 25 and a cooler 26 into the compression space 23. Consequently, the volume of high temperature working fluid in the expansion space 22, a flow path 27 and the heater 24 will decrease while the volume of low temperature working fluid in the compression spaces 23, 18, a flow path 27' and the cooler 26 will increase. Upon lifting of the displacer 21, pulsating pressure is produced in the working space to lift a flexible partitioner 17 having a hole 20. Consequently, the working fluid in the working space will perform work against the flexible partitioner 17 which will perform work against spacific load 33.

Description

[Detailed description of the invention] Industrial applications The present invention relates to improvements to Stirling engines.

Structure of the conventional example and its problems In the conventional Stirling engine, as shown in FIG. 1, there is an expansion space 1 for the working fluid. Working fluid side space of (flow paths 2, 3. heater 4. cooler 6. regenerator 6).

A displacer is used to reciprocate between the heater 4 and the cooler 6 while keeping the volume of the working space consisting of the compression spaces 7 and 8 almost constant, thereby creating pressure pulsations in the expansion space 1 and the compression spaces 7 and 8. 9 was set. The displacer 9 slides on the inner surface of the container 10 and moves up and down. When the displacer 9 moves upward, the pressure in the expansion space 1 becomes higher than the pressure under the compression space. Due to this pressure difference, the pressure in the expansion space 1 increases.
The working fluid of heater 4. Regenerator6. It moves through the cooler 5 towards the compression space 7 . Therefore, the expansion sky is 1V41.

Channel 2. The volume of the hot working fluid in the heater 4 decreases and conversely the compression space 7.8 flow path 3. The volume of cold working fluid in the cooler 6 increases.

While the displacer 9 moves from the bottom dead center to the top dead center, the volume of the working space is kept almost constant, so the average temperature of the working space is 9. the result.

The average pressure in the working space decreases. 1 On the contrary, when the displacer 9 moves from top dead center to bottom dead center, the volume of the working space is kept almost constant during this period, so the average temperature of the working space increases, and as a result, the average pressure of the working space increases. increases.

Furthermore, when the displacer 9 rises, the gas spring 15 partially surrounded by the displacer rod 14 in FIG. When it does, its volume decreases and pressure increases,
It acts to pull up the displacer.

The lc bounce space 12 changes its volume with the movement of the piston 11, acts as a gas spring, and serves to vibrate the piston 11 with an appropriate amplitude.

Further, the flow path 16 is provided so that the working fluid can flow between the compression space 7 and the compression space 8.

As described above, the displacer 9 moves up and down, thereby generating pressure pulsations in the working space, and this pressure pulsation causes the piston 11 to move up and down, resulting in 1
The working fluid in the working space receives heat from the heater 4, gives it away to the cooler 6, and performs work on the piston 11, and the piston performs work on the load 13 such as a linear alternator, compressor, pump, etc. This is what we do.

By the way, there is a clearance between the piston 11 and the inner surface of the container 10 in order to facilitate the movement of the piston 11. Therefore, when there is a differential pressure between the compression space 8 and the bounce space 12, one working fluid It moves back and forth between the compression space 8 and the bounce space 12 through the gap. At this time, container 1
The working fluid in the space 0 performs the work of flowing the working fluid due to the pressure difference between the pressure in the compression space 8 and the pressure in the bounce space 12, and most of this work is converted into heat.

Therefore, as the working fluid passes between the compression space 8 and the bounce space 12 through the gap between the piston 11 and the container 10, the working fluid does more work than when this gap is zero. Become. In other words, the engine's thermal efficiency decreases.

Furthermore, since the piston 11 and the inner surface of the container 10 move, frictional losses occur, which also reduces the thermal efficiency of the engine. In addition, since the Stirling engine encloses the working fluid in the container 10, the piston 1
When lubricating oil is put into the sliding surface between the piston 11 and the container 1o, this lubricating oil enters the regenerator 6 and decomposes, clogging the regenerator 6. A solid lubricant such as MoS 2, 47-ethylene chloride, or polyimide is applied to the surface. However, these solid lubricants tend to peel off over time. Along with this, the gap between the piston 11 and the container 10 increases, and the thermal efficiency of one engine decreases. Furthermore, as the solid lubricant peels off, the metals eventually come into contact with each other.

When this stage is reached, the friction loss further increases, and in some cases, seizure may occur, resulting in an inoperable situation.

That is, in the conventional Stirling engine, since there is a gap between the piston 11 and the inner surface of the container 1o, the working fluid passes between the compression space 8 and the bounce space 12 through the gap between the piston 11 and the container 10. There is a decrease in thermal efficiency due to friction caused by the sliding motion, and a decrease in thermal efficiency due to friction in the sliding movement.Also, solid lubricant is applied to the sliding surface between the piston 11 and the inner surface of the container 1o, so this may peel off. There was a decrease in reliability due to the occurrence of seizure.

Purpose of the Invention The present invention solves the drawbacks of the conventional Stirling engine as described above, such as a decrease in thermal efficiency due to the working fluid passing through the gap between the piston and the inner surface of the container, and a reduction in thermal efficiency due to friction between the piston and the inner surface of the container. This product eliminates three drawbacks: a decrease in thermal efficiency, and a decrease in reliability due to the occurrence of seizure due to the peeling of the solid lubricant applied to the sliding movement between the piston and the inner surface of the container. The aim is to provide a more efficient and reliable Starling engine.

Components of the Invention The present invention is a Stirling engine that has a working fluid such as He or H2 sealed in a sealed container and is equipped with a heater and a cooler. It has a partition plate that is separated into two spaces that communicate only through holes provided in the space.

Description of examples FIG. 2 is a diagram showing a general configuration of the present invention.

The present invention has a configuration very similar to a conventional free piston Stirling engine (hereinafter abbreviated as FPSE), except that the piston 11 of the conventional FPSE is replaced with a flexible diaphragm 17. Moreover, this flexible diaphragm has 18 compressed spaces.
A hole 20 is provided for communicating between the bounce space 19 and the bounce space 19. The reason for providing this hole 2o is as follows. That is.

Without the hole 20, if a large temperature difference occurs between the compression space 18 and the bounce space 19 while the FPSE is out of operation, the pressure difference between the pressure in the compression space 18 and the pressure in the bounce space 19 will be If the differential pressure that the flexible diaphragm 17 can withstand is exceeded, it may break. Therefore, this hole 20 equalizes the pressure between the compression space 18 and the bounce space 19 to prevent destruction.

On the other hand, during operation of the FPSE, [(pressure in compression space 18) - (
The pressure of the bounce space 19) is approximately 20~e o H
Although it becomes positive and negative in z.

At this time, the structure is such that the flexible partition plate 17 is not destroyed by the stress applied thereto. Further, as shown in FIG. 3, it is known that the relationship between the diameter of the hole 20 provided in the flexible partition plate 17 and the FPSEO thermal efficiency is such that the thermal efficiency decreases as the diameter of the hole 20 increases. The reason for this is that when the diameter of the hole 2o is increased, during operation, the pressure difference between the compression space 18 and the bounce space 19 changes due to a change in the pressure difference between the compression space 18 and the bounce space 19. The work required to move the fluid back and forth increases, which reduces thermal efficiency. Therefore, in order to increase thermal efficiency, it is better to make the diameter of the hole 20 as small as possible.
The minimum hole diameter that can be machined is fixed, so take this into account when deciding. 1, 28 is a container in which a working fluid is sealed, and 30 is surrounded by a displacer rod 29. A gas spring surrounded by a support part 31. When the displacer 21 descends, the volume of the gas spring 3Q decreases and the pressure increases, exerting a force to raise the displacer 21.
When the gas spring 3 rises, the volume of the gas spring 3° increases, the pressure decreases, and a force is exerted to lower the displacer 21.

Further, the flow path 32 is provided so that the working fluid can flow between the compression space 23 and the compression space 18.

In the above configuration, when the displacer 21 moves upward, the pressure in the expansion space 22 becomes higher than the pressure in the compression space 23, and this pressure difference causes the working fluid in the expansion space 22 to flow into the heater 24. Regenerator 26. The compression space 2 passes through the cooler 26
Move towards 3. Therefore, the expansion space 22. Flow path 2 completed,
The volume of hot working fluid in heater 24 is reduced;
Conversely, the compressed spaces 23, 18 . Channel 27. The volume of cold working fluid in cooler 26 increases. While the displacer 21 moves from the bottom dead center to the top dead center, the volume of the working space is kept substantially constant, so the average temperature of the working space decreases, and as a result, the average pressure of the three working spaces decreases. Conversely, when the displacer 21 moves from the top dead center to the bottom dead center, the volume of one working space is kept almost constant during this time.

The average temperature of the working space increases and as a result the average pressure of one working space increases.

As described above, the displacer 21 moves up and down,
Pressure pulsations are thereby generated in the working space. Then, [(pressure in the compression space 18) - (pressure in the bounce space 19)] becomes positive or negative and pulsates. Therefore, the resultant force of the force due to the pressure in the compression space 18 and the force due to the pressure in the bounce space 19 applied to the flexible diaphragm 17 increases, and therefore the flexible diaphragm 17 moves up and down. As a result, the working fluid in the working space receives heat from the heater 24 and releases the heat to the cooler 26.

The flexible diaphragm 17 performs work on the load 33 connected to it, such as a linear alternator, compressor, pump, etc.

By the way, as mentioned above, since the flexible diaphragm 17 is provided with a 2° hole, when the operation is stopped, there is a large difference between the temperature of the operating space 1, for example, and the temperature of the bounce space 19. Even if there is a large difference between the pressure in one working space and the pressure in the bounce space 19, the pressure is equalized by the holes 2Q, so the flexible partition plate 17 will not be destroyed. Further, the diameter of this hole 20 is so large that the thermal efficiency is not significantly different from that when the diameter of the hole 20 is O, so the thermal efficiency is also almost the same as when there is no hole 2o.

As described above, the fourth embodiment has a flexible diaphragm 17 with a hole 20 instead of the piston 11 of the conventional FPSE.
1 slides between the inner wall of the container 10 through a gap, and since no solid lubricant is used, 1 working fluid flows into the piston 1
There is no reduction in thermal efficiency due to movement between the compression space 8 and the bounce space 12 through the gap between the piston 11 and the container 1o, and there is no sliding surface between the piston 11 and the inner surface of the container 10. This has the effect of eliminating reductions in thermal efficiency and reliability due to friction loss due to motion. Furthermore, since the arrow 20 is visible on the flexible diaphragm 17, the flexible diaphragm 17 will not be destroyed due to the differential pressure between the pressure in the compression space 18 and the pressure in the bounce space 19 when the operation is stopped.

Effects of the Invention As described above, the present invention has the advantage of improved thermal efficiency and further improved reliability compared to conventional Stirling engines.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a conventional Stirling engine, FIG. 2 is a diagram showing a schematic configuration of a Stirling engine according to an embodiment of the present invention, and FIG. 3 is a diagram showing a flexible diaphragm in the same embodiment. 17 is a graph showing the relationship between the diameter of the hole 20 provided in the hole 17 and the thermal efficiency y. 17...Flexible partition plate, 19...Bounce space, 20...-hole, 21... Displacer, 24... Heater, 25...・Regenerator,
26...Cooler, 28...Container, 30...
-・Gas spring, 33... 9 items such as linear alternator, compressor, pump, etc. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] A sealed container and a fluid sealed within the sealed container. A means for heating the fluid and a means for cooling the fluid. A means for moving fluid between a space in a closed container heated by the heating means and a space cooled by the cooling means, and a means for moving a fluid between a space in the closed container that is heated by the heating means and a space cooled by the cooling means, A Stirling engine that has a partition that separates it into two communicating spaces.