JPS6013959A - Stirling engine - Google Patents

Abstract

PURPOSE:To prevent leakage of operating fluid for the engine by a method wherein a hydrogenated metal, releasing occluded hydrogen by heating upon operation and occlude the hydrogen upon stopping the operation due to temperature decrease, is provided in the vicinity of the heating section of the engine. CONSTITUTION:The expansion space 11 and the operation space 12 in an engine vessel 1 are communicated through the heating section 6. A heat re-generating section 7 and a cooling section 8 while the hydrogenated metal 9 is arranged at an intermediate position between the heating section 6 and the cooling section 8. During stopping the operation of the engine, all of the heating section, the cooling section 8 and the hydrogenated metal 9 become normal temperature and the pressure of hydrogen in the vessel 1 becomes equal to an atmospheric pressure substantially, therefore, the leakage of the hydrogen is eliminated. Upon operating the engine, the heating section is heated to about 650 deg.C, for example, the cooling section 8 is cooled to about 20 deg.C, the metal hydrogenate 9 is kept at about 90 deg.C, the hydrogen is released and the hydrogen pressure is increased to about 20atm. The engine is a free-piston type and is provided with a power generating coil 4.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a Stirling engine.

Conventional Structures and Problems The Stirling engine is operated with helium or hydrogen sealed at high pressure in order to increase its output and improve its efficiency. Conventionally, the gas remained sealed at high pressure regardless of whether the engine was running or stopped, resulting in gas leakage even when the engine was stopped, which had the disadvantage of requiring refilling within a short period of time. Ta. Stirling engines that extract output mechanically suffer from gas leakage from the shaft seal (even free-piston Stirling engines with a built-in linear generator cannot completely avoid gas seal problems). Therefore, it is an object of the present invention to provide a practical Stirling engine that does not require maintenance work such as re-filling, and does not require gas filling work for a long period of time in the conventional Stirling engine.

Structure of the Invention The present invention involves sealing a metal hydride that stores hydrogen in an engine container, and uses the hydrogen release/storage action depending on the temperature to maintain the internal pressure of the engine container at the same level as atmospheric pressure when the engine is not operating. By reducing the pressure difference between the inside and outside of the container, leakage of gas within the engine container is prevented, thereby achieving the above object.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an outline of the structure of a free piston type Stirling engine according to the present invention.

In Fig. 1, 1 is an engine container, 2 is a displacer, 13 is a power generating coil, 5 is a permanent magnet for a field, 6 is a heating section, 7 is a heat regenerator, 8 is a cooling section, 9 is a metal hydride, 11 is an expansion space in the engine container 1, 12 is the same (working space), 13 is the same spring threshold, and 14 is a gas spring space. Expansion space 1
1 and the working space 12 are the heating section 6. Heat regeneration section7. Cooling section 8
A metal hydride 9 is placed between the heating section 6 and the cooling section 8, so that the hydrogen released from it immediately spreads to each space within the container 1. . FIG. 2 is a graph showing an example of the relationship between the hydrogen charging pressure, the engine's electric output, and the power tonnage in a 15W type free-piston Stirling engine with a built-in generator.

FIG. 3 is a graph showing the relationship between temperature and dissociation pressure of a metal hydride containing LaNi6 as a main component, and the horizontal axis scale in the figure is expressed as a reciprocal scale of temperature. The heating section 6 is heated to 650"c'! by a gas burner, and the cooling section 8 is cooled to 20°C by passing water. Therefore, the intermediate part can be heated to any temperature between 20 and 650"C depending on the position. However, in this embodiment, the metal hydride 9 is placed at a position where the temperature is approximately 90°C, depending on the characteristics of the metal hydride used.

It goes without saying that different locations will be optimal if other metal hydrides are used, and that the metal hydride 9 should be placed in different locations when operating the engine at different operating pressures.

The operation will be explained below. When the engine is stopped, the heating section 6,
The cooling section 8 and the metal hydride 9 located therebetween are all at room temperature. Therefore, as is clear from the metal hydride dissociation curve in FIG. There is no problem if you leave it alone.

During engine operation, the heating section 6 is heated to about 650"C, the cooling section 8 is cooled to about 20"C, and the metal hydride 9 is heated to about 90"C, so the stored hydrogen is released and the metal hydride 9 is heated to about 90"C. As is clear from the hydrogen dissociation pressure curve in Figure 3, the hydrogen pressure in the container rises to about 2 oatmosphere.The relationship between the pressure and the electrical output of the engine is as shown in Figure 2 in the case of an extremely small engine like this example. As the pressure increases, the power increases.

Effects of the Invention As described above, in the present invention, during engine operation, hydrogen is dissociated by heating the metal hydride disposed inside the engine, and the inside of the engine is maintained at a high pressure, so that the engine operates satisfactorily.
While the engine is inactive, it stores hydrogen gas and lowers the pressure inside the engine, minimizing gas leaks, making it possible to use the engine for a long period of time without having to refill it with hydrogen gas. There are some great practical effects.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the outline of the structure of a free piston type Stirling engine according to the present invention, and Fig. 2 shows the relationship between the hydrogen filling pressure and the electrical output of the engine in a 16W type free piston type Stirling engine with a built-in generator. The graph, FIG. 3, is a graph showing the relationship between temperature and dissociation pressure of metal hydrides. /-----" Engine repair, 1--force 1tj slave city y-1--...ngyuu q Ko, q------- general shield-bo aging old man. Di1ga Suzuraba Sarayaku 1
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Claims (1)

[Claims] The engine is equipped with a metal hydride near the heated part of the engine that releases stored hydrogen by heating to increase the pressure in the working space during operation, and when the engine is not in operation, it absorbs hydrogen and lowers the pressure in the working space by lowering the temperature. Stirling engine.