JPS60243350A - Position controlling apparatus for stirling engine - Google Patents

Abstract

PURPOSE:To enable to reduce the length of pistons and to prevent leakage of work gas, by using a small-diameter plunger piston for the purpose of positioning of a power piston and a displacer piston which are reciprocated in respective work spaces formed in a container. CONSTITUTION:For instance, when a displacer 3 is moved downward, gas in a compression space 4 is carried into an expansion space 2 via a connecting pipe 12, a low-temperature heat exchanger 13, a regenerator 14, a high-temperature heat exchanger 15 and a connecting pipe 16. During the above process, the pressure of gas is raised through endothermic expansion and a power piston 7 is pushed down by the gas pressure. Thus, the power piston 7 performs work to a load 8. If an opening of a passage 18 formed in a plunger piston 17 comes to a position where it is registered with an opening of a connecting pipe 10, a compression space 6 and a balance space 9 are communicated with each other, so that the gas pressure in the compression space 6 and that in the balance space 9 become substantially equal to each other. By the resultant vibration of the power piston 7 in the vertical direction, it is enabled to determine the work position of the power piston 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in free-piston Stirling engines.

Conventional structure and its problems Conventionally, the Stirling engine, which is an external combustion engine, has high efficiency and
It has many features such as fuel efficiency and quietness, but among Stirling engines, the free piston Goris J-II is one that can be expected to have low mechanical loss and high efficiency.
Ng Sakaki - h2as.

In this type of free piston type Stirling engine, as shown in Figs. 1 and 2, the power piston 7 and/or the displacer piston 3 are not restrained by the crankshaft or co-rod and move freely. Therefore, without position control of the power vista 7 and the displacer piston 3, the operating position will be unstable, and in some cases, movable components such as the piston may collide with the wall of the cylinder body 1. For this reason, one of the conventional solutions is to make a hole in a part of the power piston 7 or the displacer piston 3, and to locate the hole (for example, at the center of vibration).
The operating position of a movable component such as a piston was determined by communicating one space (for example, the space above the piston) with another space (for example, the space below the piston).

However, with this conventional method, in order to prevent the working gas from leaking from one space to another, it is necessary to make the power piston 7 and displacer piston 3 longer than originally necessary, which makes the process difficult. The vibrations also increased due to the weight of the aged parts of the engine and the IV piston. In addition, the power piston 7 and the displacer piston 3
There is a limit to how long the piston can be, and for this reason, leakage from the gap between the power piston 7 or the displacer piston 3 and the cylinder body 1 cannot be ignored, which is one of the causes of deterioration in engine performance.

Purpose of the Invention The present invention uses a plunger with a small diameter to determine the operating position of a piston or a displacer.
This is intended to improve the above-mentioned problems, such as reducing leakage without making the piston unnecessarily long.

Structure of the Invention The present invention provides, in addition to movable components such as a piston, a plunger piston with a small cross-sectional area for pressure adjustment, either integrally with the power piston or separately, so that the plunger piston follows the movement of the power piston. When the plunger piston reaches the set position, it communicates a certain space (for example, the space above the power piston) with another space (for example, the space below the power piston), thereby adjusting the pressure in the space. , the piston position can be controlled.

When a plunger piston is used in this way, since the diameter of the plunger piston is small, the annular area formed by the gap between the plunger piston and the cylinder wall that surrounds the plunger piston can be reduced, leakage is also reduced, and pressure adjustment is Because it uses a plunger piston, there is no need to enlarge the power piston or displacer piston.

Description of examples An embodiment of the present invention will be described below.

3 to 5, 1 is the cylinder body, 2 is the expansion space, 3 is the displacer piston, 4 is the compression space,
5 is a passage connecting the compression space A and the compression space port, 6 is the compression space port, 7 is a power piston, 8 is a load, 9 is a bounce space, 10 is a communication pipe, 11 is a communication pipe provided in the piston, 1
2 is a communication pipe between the low temperature side heat exchanger and the compression space A, 13 is the low temperature side heat exchanger, 14 is the regenerator, 16 is the high temperature side heat exchanger, and 16 is between the high temperature side heat exchanger and the expansion space. communication pipe, 17
18 is a plunger, 18 is a communication pipe provided in the plunger, 19
is a communicating pipe.

Next, the operation will be described with reference to FIGS. 3 and 4, which are one embodiment of the present invention. Gas such as helium or air is generally filled in the isoseki. When the displacer 3 moves downward, the gas present in the compression space 4 is transferred to the communication pipe 12° and the low temperature side heat exchanger 1.
3. Regenerator 14. High temperature side heat exchanger 15. It is sent to the expansion space 2 through the communication pipe 16. During this process, the gas endothermically expands, the pressure of the gas increases, and the power piston 7 is pushed downward. When the displacer piston 3 then moves upwards, the gas present in the expansion space 2 passes through said passage and the heat exchanger in the opposite direction and is sent to the compression space 4 . During this process, the gas is cooled, the pressure of the gas decreases, and the power piston 7 is pulled upward. By repeating this operation, the power piston 7 performs work on the load 8. (During this process, the pressures in the spaces 2,4°6 are almost the same.

)Here, when the opening of the plan-V++zushils 71/r-I piece has two threads on each of the barring parts of 1Q and the open pipe 10 is at the same position (the state shown in Fig. 3), the compressed space 6 and The bounce spaces 9 are communicated with each other, and the gas pressures in each space are approximately the same.

In this way, the power piston 7 vibrates vertically about the position where the passage 18 and the opening of the communication pipe 10 coincide, and the operating position of the power piston 7 can be determined. Although not shown in the figure because it would be complicated, the operating position of the displacer piston 3 can also be determined in the same manner as the power piston 7. Further, although the plunger piston 17 and the power piston 7 are shown as separate parts in the figure, it goes without saying that they may be made into one piece.

Effects of the Invention As described above, by using a small-diameter plunger piston to position the power piston or displacer piston, the annular cross-sectional area due to the gap between the plunger piston and the cylinder can be reduced to the position of the power piston or displacer piston. Since the gap can be made much smaller than providing a direct positioning hole, there is less leakage of working gas from this gap, and deterioration in engine performance can be suppressed.

Furthermore, since there is no need to make the power piston or displacer piston larger than necessary, vibration can also be reduced.

Furthermore, as is clear from FIG. 4, by connecting the space above the plunger piston with the bounce space, the length e in the figure can be shortened, and the length of the plunger can be shortened.

[Brief explanation of drawings]

Figure 1 is a schematic sectional view of a conventional Stirling engine;
The figure is a partial sectional view of a conventional engine in which the piston is positioned downward; Figure 3 is a schematic sectional view of a Stirling engine according to an embodiment of the present invention; and Figure 4 is a schematic sectional view of the same engine with the piston positioned downward. It is a partial sectional view when doing so. 3...displacer piston, 7...
Power piston, 17... Piston (plunger) for position control. Name of agent Patent attorney Toshio Nakao t'z or one person Figure 1 Figure 2 Figure 3 Figure 1

Claims (1)

[Claims] A container for holding a working gas in a working space, a power piston that reciprocates inside the working space, a displacer piston, and a position control piston having a cross-sectional area smaller than that of the power piston and the displacer. Stirling engine position control device.