JPS5958140A - Stirling engine - Google Patents

Abstract

PURPOSE:To enhance the miniaturization and heat efficiency of a Stirling engine, by forming a recesses in the outer surface of cooler pipes which cool working medium from the outer surface with the use of cooling medium. CONSTITUTION:A cooler 6 shorter than a conventional cooler is formed with recesses 61 having a depth less than one-third of the pipe-wall thickness in the outer surface of the cooler pipes, and therefore, the heat transmitting area is enlarged without the proof-pressure of the cooler pipes being largely deteriorated. Thereby, the effective heat transmitting rate may be made high, and the length of the cooler is shortened so that a loss in air-feed is reduced and also the dead space volume is reduced. With this arrangement, the volume of the cooler occupied space is reduced to enhance the compression ratio. Further, the heat efficiency may be enhanced due to the reduction of loss in air-feed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly thermally efficient Stirling engine having a compact heater.

- In general, the Stirling engine is said to have features such as high thermal efficiency, low operating noise, and clean exhaust, and research and development is progressing in various directions, and it is being used as a prime mover for automobiles and air conditioners. It is said to be nearing the stage of practical application.

FIG. 1 is a block diagram of a Stirling engine that has been studied in the past. That is, in Fig. 1, (1) is the fuel introduction D
A burner that generates combustion gas by impregnation 1 introduced from C1υ and air introduced from the air inlet, (2)
(3) is a heater that heats the working fluid of the Stirling engine using combustion gas; (3) is a cooler that cools one working surface with a cooling fluid such as water; (4) is a heater between the upper heater 2) and the cooler (3). a regenerator installed in the working fluid passage to save on working fluid heating h1 and cooling; (5) V;
This is a mechanism that extracts the output of the i-engine to an external load (not shown).

In this conventional Stirling engine, the cooler (3) is a tube group heat exchanger consisting of a large number of thin metal tubes with a cross-sectional shape as shown in Figure 2. It had a structure in which cooling fluid such as water flows through it. However, since it is difficult to increase the heat transmission coefficient on the outside of the tube, it is difficult to downsize the cooler section, which makes it difficult to increase the compression ratio of the Stirling engine.

This invention aims to eliminate such drawbacks of the conventional ones, and aims to make the nola part more compact by directing the heat transmission coefficient to the outside of the tube of the thin tubes constituting the cooler Mi.
The aim is to achieve a high compression ratio in engines and, as a result, to improve thermal efficiency.

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. That is, in FIGS. 3 and 4, (
6) is a cooler that is thinner than the conventional cooler (3) shown in Fig. 1 and has a mf UI in smaller than the tube wall thickness τ formed on the outer surface, and can transmit the withstand pressure of the tube to a large extent rl. Thermal area is expanded. Note that the other $177 IIWs are the same as those shown in FIG. 1, so their explanation will be omitted.

In this way (in the case of 1η suction, the effective heat transfer coefficient is much larger than in the case of smooth 'ff outside as shown in Figures 1 and 2), so it is necessary for heat exchange. This reduces the length of the engine, reducing the air loss in this area, and reducing the dead volume of the engine (
The volume not scavenged by the piston) is reduced.

Normally in a Stirling engine, the volume occupied by the cooler section is 20% of the piston scavenging volume, but in this example, the compression ratio is improved by 10% by halving the volume occupied by the cooler section. I was able to do that.

This month, we were able to improve the thermal efficiency (more than 1%) in two ways by improving the shrinkage and reducing the loss of air supply.

Note that water is most commonly used as the cooling fluid, or chlorofluorocarbons or the like may be used to provide a cooling effect. Particularly, when external rfl' is attached and the temperature is 11 degrees as in this embodiment, it is suitable for boiling and cooling, and the efficiency can be further improved.

As described above, the Stirling engine according to the present invention has a structure in which the working fluid fed into the engine is cooled by a cooling fluid from the outside, and the inside of the cooler tube is made of cedar wood facing outward. , small size and improved thermal efficiency.
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[Brief explanation of the drawing]

Figures 1 and 2 always show a conventional Stirling engine of this type, with Figure 1 being a configuration diagram, Figure 2 being a cross-sectional view of the main parts, and Figures 3 and 4 both showing the structure of the present invention. One embodiment is shown, and FIG. 3 is a configuration diagram, and FIG. 4 is a sectional view of a main part. In the figure, (1) is a burner, (2) is a heater, II) (6
) is the cooler, (4) is the regenerator, and (5) is the mechanism. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno - 23 Procedural amendment (voluntary) Commissioner of the Japan Patent Office 1, str'l' mark 11jill, 'j 57-
No. 168062 2, title of invention Stirling engine; 3. Representative of the person making the amendment δ Part 111 Part 4, Agent 5, +r%”, y 5, Claims column 6 of the specification to be amended, Contents of the amendment As shown in the appendix Range (]) A Stirling engine characterized by forming a plurality of four parts on the outer surface of a cooler tube configured to cool the working fluid fed into the interior with a cooling fluid from the outer surface. (2) The outer surface of the tube. [Claim 1] The Stirling engine according to claim 1, wherein the four portions formed in the grooves are grooves having a depth of 1 or less of the wall thickness.] 8) The cooling fluid has a boiling cooling effect. The Stirling engine described in Section 2 or Section 2.

Claims (1)

[Scope of Claims] (1) A Stirling engine characterized in that four parts are formed on the outer surface of a cooler tube configured to cool a working fluid fed into the interior with a cooling fluid from the outer surface. The Stirling engine according to claim 1, wherein the groove portion has a depth of . (3) The Stirling engine according to item 1 or 2, wherein the cooling fluid has a boiling cooling effect.