JPH0291459A - Stirling engine - Google Patents

Abstract

PURPOSE:To make the engine compact by annularly arranging a heater in the center part of a combustion chamber, burning air-fuel mixture on the outside of the heater, and letting the gas flow from the outside to the inside of the heater. CONSTITUTION:The heater 11 of an expansion cylinder 3 is annularly arranged in the center part of a combustion chamber 37, air-fuel mixture from a burner 18 is burnt on the outside of the heater 11, the combustion gas is brought to flow from the outside to the inside of the heater 11, and is discharged through a duct 19 in the center of combustion chamber 37. In this way, as the heater 11 lets the combustion gas flow along the outer circumference and then the inner circumference and discharges it through the center of combustion chamber 37, the residence time of gas around the heater 11 is lengthened. Thus, as the burner is unnecessary to be arranged in the center of combustion chamber, the height of Stirling engine is kept low and compact shape of the engine can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a Stirling engine suitable for heating and cooling and power generation.

(Prior art) A Stirling engine, which has a reversible cycle consisting of two isothermal changes and two isovolume changes, cools a working gas such as helium gas sealed inside the engine at a low temperature (generally by water cooling using a cooler) while Isothermal) compression, and high temperature (isothermal) while externally heating (generally supplying combustion heat to a heater)
It has a fat-bloating cycle. A Stirling engine with this kind of cycle generates a large amount of waste heat that goes to the cooling water of the cooler (approximately 50% higher than the heat input), and this waste heat can be used for space heating and hot water supply, increasing the efficiency of energy use. Stirling engines are attracting attention as engines for stationary air-conditioning and heating systems due to their thermal efficiency, low pollution, and the ability to use a variety of fuels.In other words, Stirling engines are suitable as a power source for compressors in air-conditioning systems.

In such a Stirling engine, the burner is disposed on the central top wall of the combustion chamber, and the heater is disposed on the outer periphery of the combustion chamber.

(Problem to be solved by the present invention) In the conventional technology in which a heater tube is located on the outer periphery of the combustion chamber and combustion gas flows perpendicularly to this tube, the combustion gas flows in a short circuit to the exhaust port, causing heat loss. Poor transmission efficiency.

Therefore, an object of the present invention is to improve the heat transfer efficiency between the heater and the combustion gas.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention arranges a heater in a ring shape in the center of the combustion chamber, burns the air-fuel mixture outside the heater, and directs the combustion gas to the heater. To provide a Stirling engine characterized by a flow from the outside to the inside. Preferably, a duct is provided in the center of the combustion chamber and the combustion gases are discharged using this duct.

(Function) According to the present invention, the gas flows from the outer peripheral surface to the inner peripheral surface of the heater and is discharged from the center of the combustion chamber, so that the residence time of the gas around the heater is long.

(Example) Refer to FIG. 1. The illustrated Stirling engine 1 has two cylinders, and a fat expansion piston 4 in a fat expansion cylinder 3 forming an expansion chamber 2 is connected to a crank 6 via a crosshead 5. A compression piston 8 is connected to the crank 6 via a crosshead 7 at an angle of 45 degrees with respect to the center of rotation of the crank 6. The compression piston 8 reciprocates within the compression cylinder 9 and makes the volume of the compression chamber 10 variable. The expansion chamber 2 communicates with the compression chamber 10 via a heater 11, a regenerator 12, and a cooler 13, and enables a Stirling cycle of a working gas such as helium.

Let me briefly explain the combustor. A combustion air preheater 15 is arranged along the inside of the heat insulating outer cylinder 14.

Combustion air is supplied from the blower 16 and enters the preheater 15 with the supply amount adjusted by the throttle valve 17 . The air entering the preheater 15 rises and then falls, being preheated, into the annular ceramic burner 18. On the other hand, fuel is supplied to the burner 18 via the control valve 19. The air and fuel ejected from the burner 18 are mixed and combusted. The high-temperature combustion gas moves up and down around the heater 11 as shown by the arrow, exchanging heat with the working gas, flows from the central exhaust duct 19 along the inner periphery of the outer cylinder 14, and passes through the preheater 15. Then, it is discharged from the outlet 26.

The working gas enters the regenerator 12 via the heater 11, is then cooled by the cooler 13 using cooling water, and is isothermally compressed in the compression chamber 10.

Intermediate chambers 23, 24 are provided between each piston 4, 8 and the intermediate member 21, 22 holding the piston rond. This intermediate chamber 23.24 changes its internal pressure with the reciprocation of each piston 4, 8, and provides resistance to the movement of each piston 4.8.

In this example, a buffer chamber 26 is formed around the crank chamber 25, and the rain intermediate chambers 23.24 are communicated with the buffer chamber 26 via passages 27 and 28 to prevent pressure fluctuations in the intermediate chambers 23.24. .

An oil chamber 30 is formed inside the crank chamber 25 via a filter 29. This oil chamber 30 communicates with an oil pump 32 via an oil passage 31, and this pump 32 supplies oil to parts that require lubrication.

Rotational output is extracted from the crank 6 as the pistons 4 and 8 reciprocate, and this output is transmitted to the outside via the output shaft 33.

The combustor will be described with reference to FIG. The preheater 15 is arranged along the inner peripheral wall of the outer cylinder 14 covered with a heat insulating material.
It has a portion 34 for heat exchange between the combustion air and exhaust gas from the blower 16, an air passage 35 communicating with the burner 18, and a passage 41 for passing the exhaust gas. The combustion air that has entered the air passage 35 is passed through the hole 36 of the burner 18 to the combustion chamber 37.
is supplied to The fuel that has entered the pressure regulating manifold 39 through the fuel passage 38 is injected into the combustion chamber 37 from the hole 40 of the burner 18, becomes an air-fuel mixture, and is combusted outside the heater 11. The high-temperature combustion gas detours from the outside to the inside of the heater 11 as shown by the arrow, and efficiently exchanges heat with the working gas. Exhaust gas flows from the central duct 19 extending into the central space of the heater 11 to the outer peripheral side of the combustion chamber, enters the passage 41 of the preheater 15, exchanges heat with combustion air, and then passes through the outlet 2.
Ejected from 0.

The example shown in FIG. 5 supplies combustion air and fuel through the ceramic burner 18 in the example shown in FIG. 4, but the example shown in FIG. , preferably provided toward the tangential direction of the outer cylinder 14.

A fuel injection port 43 having a centerline substantially perpendicular to the centerline of the air supply port 42 is provided. Air and fuel will be injected into the combustion chamber 37 from 42.43 on both days. In this example, the flow of exhaust gas around the heater 11 and the heat exchange between the heater and the working gas are the same as in the example of FIG. 4.

In the example shown in FIG. 6, the preheater 15 is not disposed around the outer periphery of the combustion chamber 37, and the central duct 19' extends outward from the center of the cylinder 14. The air-fuel mixture is injected into the combustion chamber 37 through a plurality of pipes 44 and combusted. The combustion gas is supplied to the heater 1 as in the example shown in FIGS. 4 and 5.
The air is exhausted from the central duct 19 while heating the inner and outer circumferential surfaces of the air.

The burner 18 used in the example shown in FIG.
This will be explained using the figure below. Burner 1 shown in Figures 7-9
Reference numeral 8 is a ring-shaped member having upper and lower halves of the mating surface. A horizontal air hole 36 is bored in the mating surface 45 of the upper part 46 and the lower part 47.

Further, a fuel injection hole 40 extending in the vertical direction is bored in the lower portion 47. The upper side of the inner peripheral surface of the burner 18 is the tapered surface 4
8 to further mix the air and fuel. 1st O-
In the example shown in Fig. 12, the mating surface 4 of the upper part 46' and the lower part 47'
This is an example where 5' is stepped. As clearly shown in FIG. 11, the air holes 36 are shaped so that adjacent ones are vertically shifted due to the stepped surfaces. However, both holes 36
．． 40 has a shape whose center lines are substantially orthogonal. 1st
The example shown in FIG. 3-14 is almost the same as the example shown in FIG. 6-8, but the fuel injection hole 40 is joined halfway to the air supply hole 36.

Refer to FIG. 15. The upper part of the expansion cylinder 3 is further extended upward, and the heater 11 is arranged so as to create an annular space 50 around this extended part 49. The heater 11 is cylindrical and has a space 50 formed within its cylindrical wall, into which the extending portion 49 is inserted. As a result, this space 50 is formed with an annular passage leading to the regenerator 12 and an annular passage communicating with this passage and leading to the expansion chamber 2,
The working gas in this space 50 receives heat from the inner and outer peripheral surfaces of the heater 11.

The regenerator 12 communicating with the heater 11 is composed of a donut-shaped mesh 53 filled in an annular space 52 when a cylindrical body 51 is arranged around the expansion cylinder 3.

The mesh is made of stainless steel and has a wire diameter of 50 to 200 μm, and the mesh 53 is packed so as to occupy approximately half of the volume of the space 52.

In the example shown in FIG. 16a, in the space 52 of the regenerator 12, 50
It is filled with stainless steel metal fibers 53' having a wire diameter of ~200μ. The metal fibers 53' are packed by a mandrel 54 so as to occupy 50% of the volume of the space 52. Chapter 16b
In the example shown in the figure, the space 52 is filled with metal fibers 53# which have been previously formed into a donut shape with a bulk density of approximately 50%.

FIG. 17 shows an example in which fins 55 are used in the heater 11.

Fins 55 are provided on the inner and outer peripheral surfaces of the extension portion 49 of the expansion cylinder 3.
Furthermore, fins 55 are arranged on the inner and outer peripheral surfaces of the cylindrical heater 11.
to increase the heat transfer area. As shown in FIG. 19, the fins 55 are made of a thin stainless steel plate with concavities and convexities closely connected in a staggered manner to increase the surface area. The upper and lower flat surfaces 56 are bonded to the extension portion 49 and the inner and outer peripheral surfaces of the heater 11. The working gas and the combustion gas flow through oil passages formed with unevenness as shown by the arrows, and heat is transferred thereto.

Fins 55 shown in FIG. 18 are used in the air preheater 15 shown in FIG. Fins 55 shown in FIG. 18 are arranged in a cylindrical shape in the cylindrical passage through which the combustion air passes and the cylindrical passage through which the exhaust gas passes to preheat the combustion air.

As shown in FIG. 1, the buffer chamber 26 communicates with the passages 56 and 57 bored in a position where oil splashed in the crank chamber 25 is difficult to enter the buffer chamber 26. In this example, compared to the case where the passages 27 and 28 are directly communicated with the crank chamber 25, there is no oil contamination in the working space.

Although it has been described in connection with FIG. 1 that the oil chamber 30 is disposed below the crank chamber 25 via the filter 29, the filter 29 is positioned below the oil level of the crank chamber 25. As a result, oil can easily pass through the filter 29 due to the suction force of the pump 32.

As is clear from FIG.
They are connected with a 5 degree offset. Therefore, the structure for connecting the cooler 13 and the compression chamber 10 also requires three-dimensional elements. Please refer to FIG. 20. Head 5 of cooler 13
7, the first flange 58 is fixed through the hole. The installation of the first flange 58 using this hole is Y.
Allows for directional position adjustment. A second flange 60 fixed to the head 59 of the compression cylinder 9 through a hole allows position adjustment in the X direction. That is, by using the blank holes, both flanges 58.60 can be moved relative to both heads 57.59. One end of the vibro 1 is connected to the first
is welded into the passage of the second flange 58, and the other end is inserted into the passage of the second flange 60 via an O-ring,
The relative movement between the vibro 1 and the second flange 60 is at a position i! in the Z direction. Allow for adjustment.

(Effects) In the present invention, since it is not necessary to arrange the burner in the center of the combustion chamber, the height of the Stirling engine can be reduced and the engine can be made compact.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an example of the present invention, Fig. 2 is a partial sectional view of the oil pump section, Fig. 3 is a sectional view of the output shaft portion, and Fig. 4 is a sectional view of an example of the present invention.
The figure is a cross-sectional view showing the inside of the combustion chamber, Figures 5 and 6 are cross-sectional views showing another combustor, Figure 7 is a partial plan view of the burner, Figure 8 is a vertical cross-sectional view of the same burner, and Figure 9 is a cross-sectional view showing the inside of the combustion chamber. is a front view thereof, FIG. 10 is a partial plan view of another example of the burner, FIG. 11 is a vertical sectional view of the burner, FIG. 12 is a front view thereof, and FIG. 13 is a partial plan view of another example. Figure 14 is its cross-sectional view, Figure 15
16a and 5 are sectional views showing another example of the regenerator, FIG. 17 is a sectional view of the heater portion, FIG. 18 is a cross-sectional view of the heater, and FIG. 19 is a sectional view showing another example of the regenerator. The figure is a partial perspective view of the fin, and FIG. 20 is a partial cross-sectional view showing a structure for communicating the cooler and the compression chamber. In the diagram: l... Stirling engine, 2...
...Expansion chamber, 4...Expansion piston, 6...
...Crank, 8...Compression piston, lO・
...Compression chamber, ti...Heater, 12...
... Regenerator, 13 ... Cooler, 14 ...
... Outer cylinder, 15 ... Preheater, 18 ...
・Burner 19...Exhaust duct, 23.24
...Intermediate chamber, 25...Crank chamber, 2
6...Buffer room, 27.28...
Passage, 29...Filter, 37...
Combustion chamber, 45...Mating surface, 50...Heater space, 53...Mesh, 55...
...Fin, 58...First flange, 60.
...Second flange, 61...Pipe. Agent Patent Attorney Hideaki Kuwahara Figure 3 Figure 7 Figure 8 Figure 9 Figure 13 Figure 14 Figure 53'' Figure 17

Claims (2)

[Claims] (1) In a Stirling engine in which an expansion chamber is communicated with a compression chamber via a heater, a regenerator, and a cooler, a heater is arranged in an annular manner in the center of the combustion chamber, and the air-fuel mixture is combusted outside of the heater. A Stirling engine is characterized by flowing combustion gas from the outside to the inside of the heater. (2) The Stirling engine according to claim (1), wherein a duct is provided in the center of the combustion chamber, and the combustion gas is discharged using this duct.