JP2009257250A - Low pressure-loss stirling engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low pressure-loss Stirling engine wherein the dead volume is reduced, the flow loss is reduced, and a high-rpm engine power is ensured. <P>SOLUTION: A regenerator 5 and a cooler 4 are arranged in the same cylinder space of a cylinder liner 7 located in the coaxial inside of a cylinder 3. A comparatively wide wire-net of the regenerator is placed in the cylindrical space in a peripherally rolled-up state. The water cooler 4 is made up either of a water cooled jacket hermetically formed of a cylinder space in the cylinder liner and the coaxially outside cylinder outer-periphery and the extension of a stop member 8, or of a copper-tube coil wound around in direct contact on the outer-periphery of the cylinder. Thus, working gas is reciprocated straight and smoothly in the very small gap between the cooler formed in the cylinder liner and the large-diameter part of the regenerator thus to reduce the flow loss. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a Stirling engine aimed at greatly reducing pressure loss due to reciprocal flow loss of working gas in a cylinder so that high-speed rotation is possible in order to make the Stirling engine smaller and higher in output.

The Stirling engine is a kind of external combustion engine, which is operated as an engine in which the working gas inside the cylinder is heated and expanded from the outside via a heater and is cooled and contracted via a cooler. The greatest feature of the Stirling engine is that a regenerator is provided between the heater and the cooler, and when the working gas moves from the heating side to the cooling side, the regenerator temporarily stores heat, and the working gas is stored in the regenerator. When moving from the cooling side to the heating side, the stored heat is received and the temperature is raised to the heater.

However, since the working gas reciprocates in the cylinder in the cooling side → regenerator → heater → regenerator → cooler, a working gas flow loss (pressure loss) occurs. When the working gas is air, the engine output tends to decrease significantly at 1000 rpm, when the gas is helium gas, 1800 rpm, and even with the least viscous hydrogen gas, the rotation speed is 2500 rpm or more.
On the other hand, since the intake and exhaust are performed in one direction, the internal combustion engine has such a flow loss and rotates up to 5000 rpm, and the output increases almost in proportion to the rotation. The magnitude of the specific output relative to this weight was a brake for the practical use of Stirling engines.
In addition, the Stirling engine has a so-called wasted volume (referred to as dead volume) occupied by a piston top gap, a cooler, a regenerator, a heater, and a passage. When the dead volume increases, the engine output tends to decrease. Therefore, in order to reduce flow loss in heat exchangers such as coolers, regenerators, and heaters, increasing the cross-sectional area of the working gas does not solve the problem of increasing the dead volume. . It is most desirable for Stirling engines to reduce dead volume and flow loss at the same time.

In the current Stirling engine configuration, first, the cooler is the tube & shell type, and the working gas flows through dozens of narrow tubes with an inner diameter of about Φ1 mm, and water flows and cools outside the tubes. The flow loss due to gas is large. Also, most of the regenerators are made by laminating hundreds of stainless steel meshes with fine meshes of 100 mesh to 200 mesh perpendicular to the flow direction, which is the largest cause of flow loss. . The biggest feature of the Stirling engine is the biggest bottleneck. Although the heater has a tube length, the inner diameter of the tube can be increased, so that the flow loss is not a problem.
Further, in a general Stirling engine, a cylinder that integrally constitutes a cooler, a regenerator, and a heater generally has a flange portion, and is fixed to the engine case by the flange. For this reason, it is difficult to construct a water jacket on the outer periphery of the flanged cylinder. Although it is possible to configure a coiled coil cooler for copper pipes on the outer periphery of the cylinder, a sufficient cooling effect can be obtained due to the fact that the effective cooling length cannot be made long and the cooling mass becomes large in the flanged cylinder. There is a disadvantage that it is not possible.
Patent Publication 2005-61330 Patent Publication No. 7-259647

  In order to reduce the dead volume of the Stirling engine, reduce the flow loss, and ensure the engine output at high rotation, the regenerator and the cooler are placed in the same cylindrical space of the cylinder liner located concentrically inside the cylinder. A relatively wide wire mesh as the regenerator is disposed in a state of being wound in the circumferential direction in the cylindrical space, and the water cooler is concentrically outside the cylindrical space formed in the cylinder liner. The cooling gas is cooled by a water cooling jacket that is hermetically formed by the cylinder outer wall of the cylinder and an extension of the stop member, or by a copper tube coil wound so as to be in direct contact with the cylinder outer wall. The aim is to reduce the flow loss by straightly and smoothly reciprocating the small diameter clearance of the formed cooler and regenerator. .

In order to achieve the above object, the regenerator and the cooler are disposed in the same cylindrical space of a cylinder liner, and the water cooler is installed in a water cooling jacket or a copper pipe on a cylinder disposed concentrically outside the cylindrical space. In order to cool by a coil, one point is to directly fix the cylinder portion of the cylinder without providing a fixing flange portion on the cylinder. The present invention is characterized in that the cylinder and the engine case are fixed by a single ring member, one of which is a flange member or an engine case and the other end is fixed by being sandwiched from both sides by a stop member. To do.
In addition, the Stirling engine is characterized in that the other end of the stop member extends in the axial direction in a sealed state at two locations on the outer periphery of the cylinder to form a water jacket.

As described above, an engine that minimizes the flow loss (pressure loss) of the working gas cooler and regenerator with a minimum dead volume is provided, and water can be reliably cooled, and a wire mesh is wound. The long regenerator lengthens the passage of the working gas and has the additional effect of increasing the regenerator efficiency.
As a result, the flow loss of the working gas is reduced, and a Stirling engine that can output at a high rotation speed can be provided. The configuration of the cooler and the regenerator can be simplified, and a cheaper Stirling engine can be provided.

This configuration is most effective in a free piston Stirling engine that requires high speed rotation. Of course, a kinematic Stirling engine can also be expected to have the effect of downsizing and an inexpensive engine.

FIG. 1 shows a general configuration of a Stirling engine. Reference numeral 1 denotes a kinematic Stirling engine generator body. The engine body 1 comprises two coaxially arranged power pistons 14 'and a displacer rod 15' connected to the displacer piston 13 'with a crank mechanism 16' and a flywheel 17 'for driving with a predetermined phase difference. A drive unit, a motor & generator unit 18 ′ that operates as a motor at the time of startup, and operates as a generator after the engine is self-supporting, and heat exchangers arranged on the concentric shaft with the displacer piston 13 ′ It is comprised by three parts of the action | operation part which has cooler 4 'which is, regenerator 5', and heater 6 '.
The power piston 15 ', which is the driving portion, is fitted on the inner diameter side of the flange member 9' so as to be slidable in the axial direction, and the displacer piston 13 'is disposed on the concentric shaft inside the cylinder 3'. The cylinder liner 7 'is slidably fitted on the inner diameter side. The upper end of the power piston 14 ', the low temperature space 12' formed by the piston seal 19 'provided in the displacer piston 13', the upper end of the displacer piston 13 ', and the upper end of the cylinder 3' on the inner diameter side. And a cooler 4 ', a regenerator 5', a passage 22 ', and a heater 6' are arranged in a working gas path that connects the two spaces.
The cooler 4 'is a general tube and shell, is sealed to the cylinder 3' and coaxially fits, has a water inlet and outlet, is water cooled, and has one end at a flange member 9 '. Is fixed in the axial direction, and the other end is fixed by the shoulder of the cylinder 3 '. The regenerator 5 'is generally of a type in which several hundreds of wire meshes are laminated in the axial direction, and is arranged in a donut shape between the inner diameter side of the cylinder 3' and the cylinder liner 7 '. . Further, the cylinder 3 'has a passage 22' and a heater 6 ', and the whole is fixed to the engine case 2' by a flange portion.

FIG. 2 shows an overall configuration and an enlarged view of the present invention. Only the differences from the configuration of FIG. 1 will be described below.
The cooler 4 is not a general tube and shell, but a narrow passage formed in the inner diameter side of the cylinder 3 and the outer peripheral portion of the cylinder liner 7 coaxially fitted to the cylinder 3 is a cooling space on the working gas side. The water cooling is performed by a water jacket portion having a water inlet and outlet formed in a sealed manner with the extended inner diameter side of the stop member 8 and the outer peripheral wall of the cylinder 3. Further, the regenerator 5 is not of a general type in which several hundreds of wire meshes are laminated in the axial direction, but is disposed in the same extension space as the cooler, and is located between the inner diameter side of the cylinder 3 and the cylinder liner 7. Further, the passage 22 'in FIG. 1 is omitted, and a useless dead volume space is eliminated. Further, the entire cylinder 3 is configured to be fixed to the engine case 2 by sandwiching a ring member 10 fitted in a groove provided at one end of the cylinder 3 between a shoulder portion of the flange member 9 and one end of the stop member 8. .

FIG. 3 shows another embodiment of the present invention. Only the differences from the configuration of FIG. 1 will be described below.
The cooler 4 ″ is not a general tube and shell, but a narrow passage formed on the inner diameter side of the cylinder 3 and the outer periphery of the cylinder liner 7 fitted coaxially to the cylinder 3 is cooled on the working gas side. It becomes a space, and is water cooled with a copper pipe excellent in thermal conductivity that is tightly wound around the outer peripheral wall of the cylinder 3. If possible, silicon that increases the heat dissipation effect when winding the copper pipe Cooling efficiency is further improved by using a heat conductive agent, and the regenerator 5 is not of a type in which several hundred wire meshes are laminated in the axial direction, and is disposed in the same extended space as the cooler. Further, it is arranged between the inner diameter side of the cylinder 3 and the cylinder liner 7 so as to have a long width and is circumferentially wound, and the passage 22 'is omitted so that a useless dead volume space is eliminated. Like the syringe The entire der 3 is configured to be fixed to the engine case 2 by sandwiching a ring member 10 fitted in a groove provided at one end of the cylinder 3 between the shoulder portion of the engine case 2 and one end of the stop member 8.
The engine case 2 shows a case where the flange member 9 shown in FIG. 2 is integrally formed, and there is no structural problem.

FIG. 4 shows an embodiment of the present invention with another type of Stirling engine. Only the differences from the configuration of FIG. 1 will be described below. Reference numeral 1 ″ denotes a free piston type Stirling engine generator body.
The engine body 1 ″ includes a linear drive mechanism 16 ″ for driving a displacer rod 15 connected to a power piston 14 and a displacer piston 13 arranged on the same axis by a plurality of spring means with a predetermined phase difference, and The linear motor & generator section 18 "operates as a linear motor at the time of start-up, and operates as a generator after the engine is self-supporting, and cooling that is a heat exchanger disposed on the concentric shaft with the display thepist 13 It is composed of three parts of an operating part having a unit 4, a regenerator 5 and a heater 6.
The fixing method of the cooler 4, the regenerator 5, and the cylinder 3 is the same as that of the crank type Stirling engine of FIG.

FIG. 1 shows a general configuration of a Stirling engine. FIG. 2 shows an overall configuration and an enlarged view of the present invention. FIG. 3 shows another embodiment of the present invention. FIG. 4 shows an embodiment of the present invention with another type of Stirling engine.

Explanation of symbols

1 Stirling engine generator body 2 Engine case 3 Cylinder 4 Cooler 5 Regenerator
6 Heater 7 Cylinder liner 8 Stop member 9 Flange member 10 Ring member

Claims (3)

In a Stirling engine with a regenerator made of wire mesh and a water cooler, the regenerator and cooler can be placed in the same cylindrical space of the cylinder liner by fixing the cylinder in the axial direction with a ring member. The regenerator is arranged in a state of being wound in the circumferential direction in the cylindrical space, and is wound around a water-cooled jacket or a direct cylinder formed on a cylinder wall arranged concentrically outside the cylindrical space. A low pressure loss type Stirling engine cooled by a copper tube coil is provided.  2. The Stirling engine according to claim 1, wherein one of the ring members for fixing the cylinder in the axial direction is fixed by being sandwiched from both sides by a flange member or an engine case and the other end by a stop member. Provide an engine. 2. The Stirling engine according to claim 1, wherein one end of the stop member fixes the ring member in the axial direction, and the other end extends in the axial direction in a sealed state at two locations on the outer periphery of the cylinder. Provided is a Stirling engine characterized in that a water jacket is formed therebetween.

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