JPH0718383B2 - Stirling engine - Google Patents

Description

Description: [Object of the Invention] (Field of Industrial Application) The present invention relates to a Stirling engine, and more particularly to a Stirling engine provided with a buffer tank communicating with a space behind a piston.

(Prior Art) In recent years, as a part of energy saving, the Stirling engine has been reviewed and enthusiastic research has been conducted. There are various types of Stirling engines. For example, in the case of a two-piston system commonly called L type, a regenerative heat exchanger is provided between two power cylinders each having a power piston. Connected in a closed flow path configuration, the flow path between one end of the regenerative heat exchanger and one power cylinder is heated by a heater, and the flow path between the other end of the regenerative heat exchanger and the other power cylinder Is configured to be cooled by a cooler. This period is characterized by quietness, high theoretical thermal efficiency, and the availability of some heat source.

By the way, in this type of Stirling engine, when the piston reciprocates, the working gas in the rear space of the piston becomes a resistance, and the output and efficiency of the engine may decrease. Therefore, in order to reduce the pumping loss in the piston back space, a pipe hole is provided in the cylinder in the piston back space part, and this is connected to a buffer tank having a sufficient capacity. With this configuration, when the working gas or air in the piston back space receives a compressive force, this is released to the buffer tank through the pipe through the pipe hole provided in the cylinder in the piston back space. Conversely, when the working gas or air receives an expansion force, the working gas or air is moved from the buffer tank to the piston back space. As a result, the fluctuation range of the compression of the working gas or air in the space behind the piston is reduced, and the above problem is solved.

However, the structure having the buffer tank as described above has the following problems. That is, in order to reduce the pressure fluctuation width of the working gas or air in the space behind the piston, a pipe having a sufficiently large diameter and a buffer tank having a sufficiently large capacity are required. Therefore, there is a problem that the installation space becomes large and various inconveniences occur during assembly and maintenance.

(Problems to be Solved by the Invention) As described above, in the conventional Stirling engine, it is necessary to increase the diameter of the pipe that connects the piston back space and the buffer tank, and to increase the capacity of the buffer tank itself and the capacity of the pipe. However, there is a problem in that the installation space is increased and a great burden is imposed on the assembly and facilities.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to reduce the capacity of the buffer tank and the diameter of the pipe for connecting the buffer tank and the piston rear space, thereby reducing the installation space. It is to provide a Stirling engine that can reduce the power consumption.

[Structure of the Invention] (Means for Solving the Problems) The essence of the present invention is to temporarily reduce the pressure fluctuation range of the working gas or air in the piston back space, and then let it escape to the buffer tank.

That is, the present invention provides a Stirling engine main body having a working space in which a working fluid is enclosed and closed by a piston, and a rear space of the piston of the Stirling engine main body provided outside the Stirling engine main body. In a Stirling engine provided with a buffer tank that communicates with the crank chamber, a collecting space that connects the piston back space and the buffer tank is provided in a crank chamber portion that accommodates a crank connected to the piston.

(Operation) With the above configuration, when the working gas or air in the piston back space is compressed, the pressure fluctuation width is temporarily reduced through the gathering space, and then the working gas or air is allowed to escape to the buffer tank. become. Similarly, when the working gas or air in the space behind the piston undergoes expansion,
After the pressure fluctuation width is once reduced through the collecting space, the working gas or space is supplied from the buffer tank. Therefore, the pressure fluctuation of the working gas or air during the reciprocating motion of the piston can be effectively reduced, and the capacity of the buffer tank can be made smaller than in the conventional case. Furthermore, since the pressure difference in the gathering space / buffer tank is smaller than that in the piston space / buffer tank, the diameter of the pipe connecting them can be made smaller than before. Therefore, it is possible to reduce the installation space as a whole.

(Examples) The details of the present invention will be described below with reference to illustrated examples.

FIG. 1 is a sectional view showing a schematic configuration of a Stirling engine according to an embodiment of the present invention. Reference numeral 1 in the figure denotes a Stirling engine body. The main body 1 is roughly divided into a power cylinder 2 used for expanding a working fluid.
(Hereinafter referred to as an expansion cylinder) and a power piston 3 (hereinafter referred to as an expansion cylinder) slidably mounted in the expansion cylinder 2.
An expansion piston), a power cylinder 4 used to compress the working fluid (hereinafter referred to as a compression cylinder),
A power piston 5 slidably mounted in the compression cylinder 4 (hereinafter referred to as a compression cylinder), and a power piston 5 slidably mounted in the compression cylinder 4.
(Hereinafter referred to as a compression piston), a heat 6, a regenerative heat exchanger 7 and a cooler 8 provided between the expansion cylinder 2 and the compression cylinder 4, and a crank (connecting rod) for the expansion piston 3 and the compression piston 5, respectively. ) 9,10,
It is composed of an output shaft 13 connected via crankshafts 11 and 12.

The heater 6 has a combustion chamber 16 formed by partially arranging a heat insulating material 15 so as to surround the head 14 of the expansion cylinder 2,
A plurality of heat exchangers 17 arranged in the combustion chamber 16, a fuel supply nozzle 18 arranged so as to face the combustion chamber 16,
It is composed of an air preheater 19 which is arranged so as to surround the combustion chamber 16 and preheats air required for combustion with combustion exhaust gas.

In each heat exchanger 17, one side of each fluid passage communicates with the top of the expansion cylinder 2 and the other end communicates with the manifold 20 formed in the head 14 to form a funnel as a whole. It is arranged. The manifold 20 is connected to the regenerative heat exchanger 7 via a welded pipe 21, and the regenerative heat exchanger 7 is connected to the top of the compression cylinder 4 via a cooler 8 constituted by the heat exchanger. Then, the space surrounded by the expansion cylinder 2 and the expansion piston 3, each heat exchanger 1
7, Manifold 20, Connection pipe 21, Regenerative heat exchanger 7, Cooler 8, Closed space consisting of space surrounded by compression cylinder 4 and compression piston 5, that is, working space filled with He as working fluid Has been done. The nozzle 18 is connected to a fuel supply source (not shown) via a fuel control valve (not shown), and the air inlet 22 of the air preheater 19 is connected to the discharge side of a blower (not shown).

Further, a gathering space 30 according to the present invention is formed in a part of the crank chamber portion 25 that accommodates the cranks 9, 10 and the like. The crosshead portion 31 of the expansion piston 3 is formed with a communication hole 33 in the outer peripheral portion thereof, which communicates the piston back space 32 and the collection space 30. The communication hole 33 is formed by cutting the outer peripheral portion of the crosshead portion 31 over the entire vertical length thereof. Also, the meeting space 30 is
A portion of the crank chamber portion 25 below the cylinder is formed by a manufacturing method such as cutting or casting, and a cross head portion 31. And this gathering space 30 is
It is connected to the buffer tank 50 via a pipe 34.

On the other hand, the compression piston 5 of the compression cylinder 4 is also provided with a gathering space 40 corresponding to the gathering space 30. The gathering space 40 is communicated with the piston rear space 42 by a communication hole 43 formed by cutting the crosshead portion 41 of the compression piston 5, and is also connected with a buffer tank 50 via a pipe 44. And the meeting space
30, 40 are connected via a connection space 51 in the crank chamber portion 25. The connection space 51 is formed by manufacturing the crank chamber portion 25 by cutting or casting. If it is necessary to keep the pressure balance between the buffer tank 50 and the crank chamber 25, the connection pipe 52 may be used.

Next, the operation of the Stirling engine configured as above will be described. First, fuel is delivered from the nozzle 18 and ignited. Further, the output shaft 13 is temporarily rotated by an external power source. Since the output shaft 13 is rotated by the external power source, the expansion piston 3 and the compression piston 5 connected to the output shaft 13 via the crankshafts 11, 12, and cranks 9, 10 have a certain phase difference. Move back and forth. When the expansion piston 3 moves to the compression stroke due to this reciprocal movement, He in the expansion cylinder 2 flows into the compression cylinder 4 via each heat exchanger 7 and cooler 8, and when the expansion piston 3 reaches the top dead center. Then, most of He flows into the compression cylinder 4.
At this time, the heat of He is accumulated in the regenerative heat exchanger 7 while passing through the regenerative heat exchanger 7, and is further cooled while passing through the cooler 8. When the compression piston 5 starts to move from the bottom dead center to the top dead center with the rotation of the output shaft 13, the low temperature He in the compression cylinder 4 is compressed, and the expansion cylinder 2 is routed in the reverse path. Pour into. At this time, He absorbs heat while passing through the regeneration heat exchanger 7 and is heated to a high temperature, and is further heated when passing through each heat exchanger 17 next time. Of the high temperature flowing into the expansion cylinder 2.
He expands and pushes down the expansion piston 3. After that, the above-described operation is repeated, and the output shaft 13 continues to rotate even when the external power source is cut off, and the function as the Stirling engine is exhibited.

By the way, the reciprocating motion of the expansion piston 3 causes a pressure fluctuation of the working fluid in the piston back space 32. For example, when the piston 3 descends, the working fluid in the piston back space 32 is compressed. At this time, the piston rear space 32 has a connecting hole.
Since it is connected to the gathering space 30 via 33, the pressure fluctuation width due to the compression is once reduced by the gathering space 30. Then, the compressed working fluid will escape to the buffer tank 50 through the pipe 34. Further, when the expansion piston 3 moves up, the working fluid in the piston back space 32 is expanded. The pressure fluctuation width due to this expansion is also temporarily reduced by the action of the gathering space 30 as in the above. And
The working fluid is supplied from the buffer tank 50 through the pipe 34.

That is, the pressure fluctuation range of the working fluid in the piston back space 32 caused by the reciprocating motion of the expansion piston 3 is temporarily reduced by the gathering space 30 and then released to the buffer tank 50, whereby the pressure fluctuation in the piston back space 32 is compensated. Will be. Further, the pressure fluctuation in the piston back space 42 due to the reciprocating motion of the compression piston 5 is also compensated by the collecting space 40 and the buffer tank 50, as in the above.

Thus, according to the present embodiment, the crank chamber portion 25 is provided with the collective spaces 30, 40 communicating with the piston back spaces 32, 42, and the collective spaces 30, 40 are connected to the buffer tank 50 by the pipes 34, 44. Therefore, unlike the one in which the pressure fluctuations in the piston back spaces 32 and 42 are directly compensated by the buffer tank 50, the pressure compensation capability required for the buffer tank 50 can be small. That is, the capacity of the buffer tank 50 can be reduced. In addition, the meeting spaces 30, 40 and the buffer tank 5
Since the pressure difference from 0 is smaller than that in the case where the piston back spaces 32 and 42 and the buffer tank 50 are directly connected, the diameters of the pipes 34 and 44 can be reduced. For this reason,
It is possible to reduce the installation space of the entire device and facilitate assembly and maintenance. In addition, there is no need to newly use special parts, and the piston 3,
There is also an advantage that it can be easily realized by processing the crosshead portions 31 and 41 of 5 and the crank chamber portion 25.

FIG. 2 is a sectional view showing a schematic configuration of another embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals,
The detailed description is omitted.

The difference between this embodiment and the above-described embodiment is that the connecting collective space 51 connecting the collective spaces 30 and 40 is made larger than in the case of FIG. 1 by using a manufacturing method such as casting.
This gathering space 51 has a buffer tank 50 through a pipe 53.
It is connected to the. In this case, only one pipe may be used to connect the buffer tank 50 and the gathering spaces 30, 40. Of course, even with such a configuration, the same effect as that of the previous embodiment can be obtained.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be carried out without departing from the scope of the invention. Although the embodiment is an example applied to the two-piston method, the present invention can also be applied to the displacer method. Furthermore, the conditions such as the arrangement position and size of the meeting space are
It can be changed appropriately according to the specifications.

[Effects of the Invention] As described in detail above, according to the present invention, a collective space is provided between the piston back space and the buffer tank, and the buffer tank is provided after the pressure fluctuation of the working fluid in the piston back space is temporarily reduced by the collective space. Since there is no need to use a pipe with a large diameter and a buffer tank with a sufficiently large capacity to reduce the fluid resistance in the space behind the piston, a pipe with a smaller diameter and a smaller capacity than the conventional one can be eliminated. You can use your own buffer tank. Therefore, the installation space is downsized,
It becomes possible to realize a compact Stirling engine with good performance.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic structure of a Stirling engine according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a schematic structure of another embodiment. 1 ... Stirling engine body, 2 ... expansion cylinder, 3 ... expansion piston, ... compression cylinder, 5 ... compression piston, 6 ... heater, 7 ... regenerative heat exchanger, 8 ...
… Cooler, 16 …… combustion chamber, 17 …… heat exchanger, 18 …… nozzle, 19 …… space preheater, 30,40 …… collecting space, 31,41 ……
Cross head part, 32,42 …… Piston back space, 33,43…
… Communication holes, 34,44,53 …… pipes, 50 …… buffer tanks, 51 …… connection space.

Claims (1)

[Claims] 1. A Stirling engine main body having a working space in which a working fluid is enclosed and closed by a piston, and a space provided outside the Stirling engine main body in the back space of the piston of the Stirling engine main body. A Stirling engine, comprising: a buffer tank that communicates with a crank chamber that houses a crank connected to the piston; and a collective space that connects the piston back space and the buffer tank.