Stirling engine

Abstract

To provide a Stirling engine having high degree of freedom in installation of a heater heat exchanger.SOLUTION: A Stirling engine 10 has an engine body E including at least an engine portion 11 and a cooler heat exchanger 14, and a heater structure H including at least a heater heat exchanger 12. The engine body E and the heater structure H are independent structures, and the engine body E and the heater structure H are connected through a connection pipe portion.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a Stirling engine. [Background technology]

[0002] Stirling engines can recover power from a wide variety of high-temperature heat sources, and in recent years have been attracting attention as a technology for recovering and generating power from existing high-temperature waste heat (from waste incinerators, factory furnaces, etc.). In addition, in a Stirling engine, the heater heat exchanger, regenerator, and cooler heat exchanger are connected in this order to the high-temperature space (expansion space) above the piston. A Stirling engine generates power by inserting a heater heat exchanger into a high-temperature heat source and absorbing heat from it.

[0003] Conventional Stirling engines (e.g., Patent Documents 1 to 3) have a structure in which a heater heat exchanger is directly connected to the expansion space and the regenerator, and the heater heat exchanger and the engine (including the expansion space) are arranged in close proximity to each other. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-259646 [Patent Document 2] Japanese Patent Application Publication No. 10-213012 [Patent Document 3] Patent No. 5533713 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional Stirling engines have a problem that the degree of freedom in installing the heater heat exchanger is small, making it difficult to install the engine to suit a wide variety of high-temperature heat sources. For example, in Patent Document 1, the heater heat exchanger is arranged in the piston sliding direction of the engine (on the cylinder axis), so if the piping for the high-temperature heat source gas is installed directly beside the engine, the heater heat exchanger cannot be inserted into the heat source piping.

[0006] The present invention has been made in consideration of the above problems, and has an object to provide a Stirling engine that allows a high degree of freedom in installing a heater heat exchanger. [Means for solving the problem]

[0007] In order to solve the above problems, the Stirling engine of the present invention is a Stirling engine having an engine section, a heater heat exchanger, a regenerator, and a cooler heat exchanger, and is characterized in that an engine body including at least the engine section and the cooler heat exchanger and a heater structure including at least the heater heat exchanger are separate structures, and the engine body and the heater structure are connected via a connecting pipe section.

[0008] According to the above configuration, the positional relationship between the engine body and the heater structure can be easily changed by changing the shape of the connecting pipe (for example, by replacing the connecting pipe). This increases the degree of freedom in installing the heater heat exchanger, and makes it easy to install the heater heat exchanger for a wide variety of high-temperature heat sources.

[0009] Moreover, the Stirling engine may be configured such that the regenerator and the cooler heat exchanger are disposed rearward of the cylinder, and the upper end position of the regenerator is higher than the upper end position of the cylinder.

[0010] According to the above configuration, by positioning the upper end of the regenerator higher than the upper end of the cylinder, it becomes easier to ensure a space for arranging the connecting pipe portion between the regenerator, the cylinder, and the heater heat exchanger.

[0011] The Stirling engine may be a double-acting engine in which a plurality of cylinders arranged in a straight line with respect to a crankshaft of the engine section are driven.

[0012] In the above Stirling engine, the heater heat exchanger may be configured such that a group of heater thin tubes for a plurality of cylinders is arranged in an annular shape.

[0013] According to the above configuration, by arranging the heater thin tube groups for a plurality of cylinders in an annular shape in the heater heat exchanger, it is possible to realize a compact arrangement of the heater thin tube groups.

[0014] The Stirling engine may be configured such that the longitudinal direction of the heater heat exchanger intersects with the sliding direction of the piston in the cylinder.

[0015] The Stirling engine may further include a first support member that holds the heater structure.

[0016] Moreover, the Stirling engine may have a configuration including a second support member that holds the regenerator.

[0017] Moreover, the Stirling engine can be configured to include an opening / closing valve in a working fluid path connecting the low-temperature chamber of the cylinder and the cooler heat exchanger, and the opening / closing valve can be used to partially close the working fluid path when the engine is stopped.

[0018] According to the above configuration, engine stop control can be safely performed using inexpensive valves such as butterfly valves. In addition, the on-off valve partially blocks the working fluid path, thereby preventing the load (compression pressure) on the closed path from becoming too large, and thus avoiding damage to parts, etc.

[0019] The Stirling engine can also be configured to include a bypass path connecting the low-temperature chambers of cylinders that are 180° out of phase with each other, and a communication valve provided in the bypass path, and the communication valve is closed to block the bypass path while the engine is operating, and the communication valve is opened to open the bypass path when the engine is stopped.

[0020] According to the above configuration, by communicating the low-temperature chambers of cylinders that are 180° out of phase with each other, it is possible to quickly stop the engine without applying an overload to parts, etc. when the engine is stopped.

[0021] The Stirling engine may be configured so that the engine output can be adjusted by controlling the opening and closing valve or the communication valve to an arbitrary opening degree during engine operation.

[0022] According to the above configuration, by making the engine output adjustable, it is possible to reduce the engine output when, for example, the temperature of the high-temperature heat source becomes too high, thereby protecting the engine components.

[0023] The Stirling engine may also have a starter motor for starting the engine, and when starting the engine, the starter motor is started with the communication valve open, and after the engine is started, the communication valve is closed and the starter motor is stopped.

[0024] According to the above configuration, the load on the engine is reduced by opening the communication valve when the engine is started, which makes it possible to use a small starter motor.

[0025] In the Stirling engine, the regenerator may be included in the engine body.

[0026] According to the above configuration, since the regenerator and the cooler heat exchanger are both cylindrical and similar in shape, including the regenerator in the engine body and connecting the regenerator and the cooler heat exchanger in a fixed manner is advantageous for miniaturizing the Stirling engine.

[0027] In the Stirling engine, each of the connecting pipes constituting the connecting pipe section may be configured so that a heat storage body is provided inside the connecting pipe wall over the entire pipe path.

[0028] According to the above-mentioned configuration, the heat storage effect of the heat storage body allows the connecting pipe to have the same function as a regenerator, and the output of the Stirling engine can be improved by effectively utilizing heat.

[0029] In the Stirling engine, the heat storage body may have a central cavity.

[0030] According to the above-mentioned configuration, the cavity serves as a passage for the working fluid, and an increase in pressure loss due to the heat storage body in the connecting pipe can be suppressed.

[0031] In addition, in the above Stirling engine, the connecting pipe portion can be detachable from the engine body and the heater structure, and a metal O-ring can be disposed on the sealing surface between the connecting pipe portion and the connected members.

[0032] According to the above configuration, the connecting pipe portion can be attached and detached from the engine body and the heater structure, making it easy to change the positional relationship between the engine body and the heater structure, and the use of a metal O-ring provides sealing in areas that require resistance to high temperatures. Effect of the Invention

[0033] In the Stirling engine of the present invention, the engine body and the heater structure are separate structures and are connected via a connecting pipe section, which increases the freedom of installation of the heater heat exchanger and provides the advantage that the heater heat exchanger can be easily installed for a wide variety of high-temperature heat sources. [Brief description of the drawings]

[0034] [Figure 1] FIG. 1 is a perspective view showing an external appearance of a Stirling engine, illustrating one embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of the Stirling engine of FIG. 1, seen from a different direction. [Diagram 3] FIG. 1 is a schematic diagram showing a general configuration of a Stirling engine. [Figure 4] FIG. 2 is an explanatory diagram showing an example of the positional relationship between a Stirling engine and a high-temperature heat source. [Diagram 5] FIG. 4 is an explanatory diagram showing an example of a couple acting on a crankshaft. [Figure 6] FIG. 4 is an explanatory diagram showing a preferred example of a couple acting on a crankshaft. [Figure 7] FIG. 1 is a schematic diagram showing a general configuration of a Stirling engine. [Figure 8] FIG. 2 is an enlarged perspective view of a connecting pipe portion in the Stirling engine. [Figure 9] FIG. 2 is a diagram showing the relative positions of a regenerator, a cooler heat exchanger, and a cylinder in a Stirling engine. [Figure 10] FIG. 4 is a plan view showing an example of the arrangement of heater thin tube groups in a heater heat exchanger. [Figure 11] FIG. 2 is a perspective view showing an example of the appearance of a connecting pipe. [Figure 12] FIG. 1 is a schematic diagram showing a general configuration of a Stirling engine. [Figure 13] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] [First embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Figures 1 and 2 are perspective views showing the appearance of a Stirling engine 10 according to the embodiment 1. Figure 3 is a schematic diagram showing a general configuration of the Stirling engine 10.

[0036] 1 and 2, the Stirling engine 10 has an engine section 11, a heater heat exchanger 12, a regenerator 13, a cooler heat exchanger 14, and a connecting pipe section 15. In the Stirling engine 10 shown in Fig. 1 and 2, a generator 20 is connected to a crankshaft 115 (see Fig. 3) of the engine section 11, and the generator 20 can generate electricity by driving the Stirling engine 10.

[0037] In the Stirling engine 10, a heater heat exchanger 12 is inserted into a high-temperature heat source (for example, a high-temperature pipe through which a high-temperature fluid flows), and the working fluid is heated in the heater heat exchanger 12. Furthermore, in the cooler heat exchanger 14, the working fluid is cooled by cooling water (means for supplying the cooling water is not shown). The Stirling engine 10 is configured to drive the engine section 11 by the movement of the working fluid thus heated / cooled. The engine section 11 may be a single-cylinder type engine or a multi-cylinder type engine, but in this embodiment 1, a four-cylinder type engine section 11 is shown as an example.

[0038] As shown in FIG. 3, the engine unit 11 has four cylinders 111A to 111D (simply referred to as cylinders 111 when no particular distinction is made). Here, the four cylinders arranged in a straight line with respect to the crankshaft 115 are referred to as cylinders 111A to 111D in the order of their arrangement. Each cylinder 111 is provided with a piston 112, and a high-temperature chamber 113 is provided on one side (upper side in FIG. 3) of the sliding direction of the piston 112 (vertical direction in FIG. 3), and a low-temperature chamber 114 is provided on the other side (lower side in FIG. 3). The high-temperature chamber 113 is connected to the heater heat exchanger 12, and the low-temperature chamber 114 is connected to the cooler heat exchanger 14. The heater heat exchanger 12 and the cooler heat exchanger 14 are connected with the regenerator 13 sandwiched therebetween. The regenerator 13 serves as a heat storage means between the heater heat exchanger 12 and the cooler heat exchanger 14, storing heat from the working fluid when the working fluid moves from the heater heat exchanger 12 to the cooler heat exchanger 14, and recovering the heat to the working fluid when the working fluid flows in the opposite direction, thereby making effective use of the heat. The Stirling engine 10 shown in Fig. 3 is a four-cylinder double-acting engine, and the heater heat exchanger 12 and the cooler heat exchanger 14, which are connected with the same regenerator 13 between them, are each connected to a different cylinder 111.

[0039] The operation of the Stirling engine 10 is achieved by repeating a cycle in which the piston 112 in each cylinder 111 sequentially takes a first position (top dead center position: cylinder 111A in FIG. 3), a second position (a position where the crankshaft 115 is rotated 90° from the top dead center position while the piston 112 moves downward: cylinder 111D in FIG. 3), a third position (bottom dead center position: cylinder 111C in FIG. 3), and a fourth position (a position where the crankshaft 115 is rotated 90° from the bottom dead center position while the piston 112 moves upward: cylinder 111B in FIG. 3).

[0040] The Stirling engine 10 according to the present embodiment 1 is characterized in that an engine body E (see FIG. 4) including at least an engine section 11 and a cooler heat exchanger 14 and a heater structure H (see FIG. 4) including at least a heater heat exchanger 12 are separate structures, and these are connected via a connecting pipe section 15. The regenerator 13 may be included on the engine body E side, or on the heater structure H side. In the present embodiment 1, a configuration in which the regenerator 13 is included on the engine body E side is exemplified, and in this case, the connecting pipe section 15 is configured to include a plurality of connecting pipes connecting the heater heat exchanger 12 and the regenerator 13, and a plurality of connecting pipes connecting the heater heat exchanger 12 and the high-temperature chambers 113 of each cylinder 111.

[0041] When the regenerator 13 is included on the heater heat exchanger 12 side, the connecting pipe section 15 includes a plurality of connecting pipes connecting the regenerator 13 and the cooler heat exchanger 14, and a plurality of connecting pipes connecting the heater heat exchanger 12 and the high-temperature chambers 113 of each cylinder 111. However, since the regenerator 13 and the cooler heat exchanger 14 are both cylindrical and similar in shape, it is advantageous for the size reduction of the Stirling engine 10 to have them integrally connected, and therefore it is preferable to include the regenerator 13 on the engine body E side.

[0042] In this way, the Stirling engine 10, which connects the engine body E and the heater structure H via the connecting pipe section 15, can easily change the positional relationship between the engine body E and the heater structure H by changing the shape of the connecting pipe section 15 (for example, by replacing the connecting pipe section 15). In other words, the heater heat exchanger 12 can be easily installed for a wide variety of high-temperature heat sources.

[0043] For example, in the example shown in Fig. 4, the heater structure H is disposed so as to extend laterally from the engine body E, and when the high-temperature heat source on which the heater heat exchanger 12 is to be disposed is a high-temperature pipe 50A present on the side of the engine body E, the heater heat exchanger 12 can be easily installed with respect to the high-temperature heat source. However, when the high-temperature heat source on which the heater heat exchanger 12 is to be disposed is a high-temperature pipe 50B present above the engine body E, it is preferable that the heater structure H is disposed so as to extend upward, not laterally, from the engine body E. In the Stirling engine 10 according to the first embodiment, by changing the shape of the connecting pipe portion 15, the heater structure H can also be disposed so as to extend upward from the engine body E with ease.

[0044] In the Stirling engine 10, if the engine body E and the heater structure H are supported only by the connecting pipe section 15, there is a problem with strength. If the support strength of the Stirling engine 10 is weak, the vibration of each of the multiple cylinders 111 cannot be suppressed, and the vibration of the engine as a whole increases. In addition, for example, as shown in Figs. 1 and 2, if the heater structure H has a horizontal structure that extends laterally from the engine body E (in other words, a structure in which the longitudinal direction of the heater heat exchanger 12 is perpendicular to the sliding direction of the piston 112 in the cylinder 111), there is a risk of an unbalanced load being generated in the connecting pipe section 15 due to the weight of the heater structure H.

[0045] For this reason, the Stirling engine 10 according to this embodiment preferably has support members (for example, frames 31, 32 in FIG. 1) that hold the engine body E and the heater structure H. The frame 31 supports the heater heat exchanger 12, which is connected horizontally to the engine body E, from the engine stand 33 and the cylinder block of the engine section 11, and corresponds to the first support member described in the claims. The frame 32 connects the heater heat exchanger 12 and each regenerator 13, and also connects and supports the regenerators 13 with each other, and corresponds to the second support member described in the claims. These support members can suppress vibration of the Stirling engine 10. In addition, it becomes possible to adopt a heater horizontal structure that could not be realized with the conventional structure.

[0046] [Embodiment 2] In the second embodiment, it is assumed that the Stirling engine 10 is a four-cylinder double-acting engine. That is, in the Stirling engine 10, as shown in Fig. 3, the pistons 112 are driven with a phase shift of 90° in each of the four cylinders 111A to 111D (specifically, the phase of the pistons 112 is delayed by 90° in the order of the cylinders 111A to 111D). If a reference cylinder (for example, cylinder 111A) is defined as the first cylinder, and the second to fourth cylinders are defined in order of the phase delay from the first cylinder, in the example of Fig. 3, cylinder 111B is the second cylinder, cylinder 111C is the third cylinder, and cylinder 111D is the fourth cylinder.

[0047] In the case of a double-acting cylinder engine in which four cylinders are arranged linearly with respect to the crankshaft 115, a couple of forces occurs between two cylinders that are 180° out of phase with each other, and this couple of forces causes engine vibration and applies a load (bending stress) to the crankshaft. In the example of FIG. 3, the four cylinders 111 are arranged in the order of the first cylinder to the fourth cylinder, and couples occur between the first cylinder and the third cylinder, and between the second cylinder and the fourth cylinder. Also, as shown in FIG. 5, if the force that each cylinder applies to the crankshaft 115 is F and the pitch between two adjacent cylinders is L, the maximum couple N acting on the crankshaft 115 (for example, the couple between the first cylinder and the third cylinder) is N=2FL.

[0048] In contrast, in the second embodiment, the cylinder arrangement order is devised to suppress (minimize) the couple generated in the crankshaft 115. Specifically, the cylinders are arranged so that cylinders with a phase difference of 180° are close to each other (adjacent to each other). For example, as shown in FIG. 6, by arranging the first and third cylinders adjacent to each other and the second and fourth cylinders adjacent to each other, the maximum couple N acting on the crankshaft 115 (for example, the couple between the first and third cylinders) becomes N=FL. Note that, although FIG. 6 shows the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder arranged in this order, the order of the fourth cylinder and the second cylinder may be reversed.

[0049] In a four-cylinder double-acting engine, the set of heater heat exchanger 12, regenerator 13, and cooler heat exchanger 14 is connected between cylinders that are out of phase with each other by 90°. Taking Fig. 3 as an example, the set of heater heat exchanger 12, regenerator 13, and cooler heat exchanger 14 is connected between cylinder 111A, which is the first cylinder, and cylinder 111B, which is the second cylinder. Specifically, cooler heat exchanger 14 is connected to low temperature chamber 114 on the side of cylinder 111A, which is the advanced phase, and heater heat exchanger 12 is connected to high temperature chamber 113 on the side of cylinder 111B, which is the delayed phase. Similar connection relationships exist between cylinder 111B, the second cylinder, and cylinder 111C, the third cylinder, between cylinder 111C, the third cylinder, and cylinder 111D, the fourth cylinder, and between cylinder 111D, the fourth cylinder, and cylinder 111A, the first cylinder.

[0050] 3 shows an arrangement of the cylinders relative to the crankshaft 115 in the order of the first to fourth cylinders (the arrangement corresponding to FIG. 5). In contrast, if the cylinders are arranged in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder (the arrangement corresponding to FIG. 6) in order to reduce the load on the crankshaft 115, the connections of the heater heat exchanger 12, the regenerator 13, and the cooler heat exchanger 14 between the cylinders will be diagrammatically as shown in FIG.

[0051] The heater heat exchanger 12 is composed of a group of heater thin tubes so that efficient heat exchange can be performed when inserted into a high-temperature heat source. In the case of a conventional structure in which the engine body E and the heater structure H are integrally formed and the heater heat exchanger 12 is directly connected to both the high-temperature chamber 113 of the engine section 11 and the regenerator 13 (connected without passing through the connecting pipe section 15), it is difficult to obtain a connection structure such as that shown in Fig. 7. That is, in the heater heat exchanger 12, a compact arrangement of heater thin tube groups for four cylinders (for example, a regular arrangement of heater thin tube groups as shown in Fig. 10) is impossible.

[0052] In contrast, in the Stirling engine 10 according to the second embodiment, as in the first embodiment, the engine body E and the heater structure H are separate structures, and are connected via a connecting pipe section 15. For this reason, as shown in Fig. 8, the heater heat exchanger 12 and the regenerator 13, and the heater heat exchanger 12 and the high-temperature chamber 113 of each cylinder 111 can be connected with a high degree of freedom by a plurality of connecting pipes in the connecting pipe section 15. As a result, the heater heat exchanger 12 can be compactly arranged in a heater thin tube group for four cylinders, regardless of the connection relationship with the regenerator 13 and the cylinders 111.

[0053] More specifically, as shown in Fig. 9, it is preferable that the regenerator 13 and the cooler heat exchanger 14 are vertically disposed in close proximity to the rear of the cylinder 111, and the upper end position P1 of the regenerator 13 is located above the upper end position P2 of the cylinder 111. This makes it easier to ensure a space for arranging the connecting pipe section 15 between the regenerator 13, the cylinder 111, and the heater heat exchanger 12. Also, in the heater heat exchanger 12, it is preferable to arrange heater thin tube groups for four cylinders in an annular shape, as shown in Fig. 10. This makes it possible to realize a compact arrangement of the heater thin tube groups in the heater heat exchanger 12.

[0054] The connecting pipe section 15 may be configured so that a connecting pipe 150 as exemplified in Fig. 11 is individually connected between the heater heat exchanger 12 and the regenerator 13, or between the heater heat exchanger 12 and the cylinder 111 (detachable from the engine body E and the heater structure H). The connecting pipe 150 is preferably configured so that a metal O-ring 151 is disposed on the sealing surface between the connecting pipe 150 and the connected member (the heater heat exchanger 12, the regenerator 13, or the cylinder 111) to obtain airtightness. As the metal O-ring 151, a hollow metal O-ring gasket having high temperature resistance or the like may be used.

[0055] Third Embodiment The Stirling engine 10 is a passive engine, and basically continues to operate as long as heat is supplied from a high-temperature heat source (it stops operating when the heat supply is stopped). However, it may be necessary to stop the operation of the engine in an emergency or the like. In this third embodiment, a suitable example of an engine stop configuration for the Stirling engine 10 will be described.

[0056] The Stirling engine 10 can be stopped by stopping the movement of the working fluid. For this reason, the Stirling engine 10 according to the third embodiment can be configured to have an opening and closing valve 16 (see FIG. 1) provided in the low-temperature part path of the working fluid (the working fluid path connecting the low-temperature chamber 114 of the cylinder 111 and the cooler heat exchanger 14), and the opening and closing valve 16 is opened during the engine operation, and the engine can be stopped by closing the opening and closing valve 16. In principle, the path in which the opening and closing valve 16 is provided is not particularly limited, and it is also possible to provide the opening and closing valve 16 in the high-temperature part path (the working fluid path connecting the high-temperature chamber 113 of the cylinder 111 and the heater heat exchanger 12). However, in the Stirling engine 10, since the high-temperature part path is the connecting pipe part 15, the high-temperature part path is not suitable for arranging the opening and closing valve 16, and it is preferable that the opening and closing valve 16 is provided in the low-temperature part path.

[0057] The type of the opening / closing valve 16 used is not particularly limited, and for example, an inexpensive valve such as a butterfly valve can be used. In this case, if the opening / closing valve 16 is one that completely blocks the path, the load (compression pressure) on the closed path may become too large, which may cause damage to parts, etc. For this reason, it is preferable that the opening / closing valve 16 is a perforated valve that allows the working fluid to pass to a certain extent (partially blocks the path) rather than completely blocking the path. In other words, the opening / closing valve 16 can stop the engine by simply reducing the flow path area and reducing the amount of movement of the working fluid, even if it does not completely block the path. More specifically, the passage blocking area of ​​the opening / closing valve 16 is set to the maximum area that does not damage the engine due to the compression pressure generated by the blockage, and to an area that can reliably stop the engine (engine output≦mechanical loss).

[0058] Furthermore, the opening and closing valve 16 may be one that can adjust the flow passage area of ​​the path using a rotary solenoid or the like. In this case, it is possible to control the flow passage area of ​​the path to gradually decrease, which makes it possible to avoid a sudden stop of the engine and reduce the load applied to the piston 112 when the engine is stopped.

[0059] As a modified example of the Stirling engine 10 according to the third embodiment, a configuration shown in Fig. 12 is also possible. The Stirling engine 10 shown in Fig. 12 has a configuration in which the low-temperature chambers 114 of the cylinders 111 that are 180° out of phase with each other are connected by a bypass path 17, and a communication valve 171 is provided in the bypass path 17. In the example of Fig. 12, the cylinders 111A and 111C are connected by the bypass path 17, and the cylinders 111B and 111D are connected by the bypass path 17.

[0060] 12, the engine can be stopped by closing the communication valve 171 during engine operation and opening the communication valve 171 to connect the bypass path 17 (connecting the low-temperature chambers 114 of the cylinders 111 that are 180° out of phase with each other). With this configuration, the engine can be stopped quickly without applying an overload to the parts when the engine is stopped.

[0061] When the engine stop configuration in Fig. 12 is applied to the Stirling engine 10 that employs the cylinder arrangement shown in Fig. 6, the cylinders that are 180° out of phase with each other are arranged adjacent to each other, so the bypass path 17 can be shortened. This makes it possible to suppress the generation of wasted volume and increased costs due to the bypass path 17. Also, it is possible to reduce horsepower loss at start-up when the bypass path 17 is long.

[0062] Furthermore, in the Stirling engine 10 according to the third embodiment, the opening of the on-off valve 16 and the communication valve 171 can be adjusted, so that they can be used to control the engine output. For example, when the temperature of the high-temperature heat source becomes too high, the on-off valve 16 can be closed somewhat and the communication valve 171 can be opened somewhat to reduce the engine output, thereby protecting the engine components.

[0063] Fourth embodiment In the fourth embodiment, a preferred example of engine startup control of the Stirling engine 10 will be described.

[0064] The Stirling engine 10 requires a starter motor 40 (see FIG. 1) to start up. Naturally, the larger the engine load (pressure loss) when starting up the Stirling engine 10, the larger the motor required for this starter motor 40.

[0065] In contrast, the Stirling engine 10 according to the fourth embodiment is based on the configuration shown in Fig. 12 and is characterized by using a communication valve 171 to reduce the engine load at start-up. That is, the Stirling engine 10 according to the fourth embodiment starts the starter motor 40 with the communication valve 171 open at start-up. The Stirling engine 10 reduces the engine load by opening the communication valve 171, which makes it possible to use a small starter motor 40. Then, when the engine speed reaches a predetermined value, the communication valve 171 is closed, the starter motor 40 is stopped, and the engine operation can be maintained.

[0066] Fifth embodiment The above-mentioned Stirling engine 10 is characterized in that the engine body E and the heater structure H are separate structures, and are connected via a connecting pipe section 15. In this structure, the connecting pipe section 15 becomes a dead volume that does not contribute to the heat cycle, and can be a factor in reducing the output of the Stirling engine 10. In this fifth embodiment, a suitable example for suppressing the output reduction caused by the connecting pipe section 15 will be described.

[0067] FIG. 13 is a cross-sectional view of a connecting pipe 150 used in the connecting pipe section 15. The connecting pipe 150 shown in FIG. 13 has a heat storage body 153 such as a wire mesh or a metal nonwoven fabric provided inside a connecting pipe wall 152 over the entire pipe. The heat storage body 153 preferably has a hollow portion 154 at its center. When a high-temperature working fluid passes through the connecting pipe 150 having such a configuration, heat is stored in the heat storage body 153, and heat radiation to the outside can be reduced. Furthermore, by making the center portion of the heat storage body 153 into the hollow portion 154, the hollow portion 154 becomes a working fluid passage, and an increase in pressure loss due to the heat storage body 153 can be suppressed.

[0068] The connecting pipe 150 shown in FIG. 13 can have the same function as the regenerator 13 due to the heat storage effect of the heat storage body 153, and can improve the output of the Stirling engine 10 by effectively utilizing heat.

[0069] The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present invention is not interpreted solely by the above-described embodiments, but is defined by the claims. Also, all modifications within the scope and meaning equivalent to the claims are included. [Explanation of symbols]

[0070] 10. Stirling Engine 11 Engine section 111 cylinders 112 Piston 113 High temperature chamber 114 Cold room 115 Crankshaft 12 Heater heat exchanger 13 Regenerator 14 Cooler heat exchanger 15 Connecting pipe section 150 Connecting pipe 151 Metal O-ring 152 Connecting pipe wall 153 Heat storage body 154 Cavity 16 Opening and closing valve 17 Bypass Route 171 Connecting valve 20. Generator 31 Frame (first support member) 32 Frame (second support member) 33 Engine stand 40 Starter motor 50A High Temperature Pipe 50B High Temperature Pipe E Engine body H Heater structure

Claims

1. A Stirling engine having an engine section, a heater heat exchanger, a regenerator, and a cooler heat exchanger, an engine body including at least the engine section and the cooler heat exchanger and a heater structure including at least the heater heat exchanger are separate structures; The engine body and the heater structure are connected via a connecting pipe portion, A Stirling engine characterized in that the regenerator and the cooler heat exchanger are arranged on the opposite side of the heater heat exchanger with respect to a cylinder included in the engine section, and an upper end position of the regenerator is higher than an upper end position of the cylinder.

2. 2. The Stirling engine of claim 1, The Stirling engine is a double-acting engine in which a plurality of the cylinders arranged in a straight line with respect to a crankshaft of the engine section are driven.

3. 3. A Stirling engine according to claim 2, A Stirling engine, characterized in that in the heater heat exchanger, a group of heater thin tubes for the plurality of cylinders are arranged in an annular shape.

4. A Stirling engine according to any one of claims 1 to 3, 13. A Stirling engine, comprising: a heater heat exchanger arranged such that a longitudinal direction of the heater heat exchanger intersects with a sliding direction of a piston in the cylinder.

5. 5. A Stirling engine according to claim 4, A Stirling engine comprising: a first support member for supporting said heater structure.

6. 6. A Stirling engine according to claim 4 or 5, A Stirling engine comprising: a second support member for supporting the regenerator.

7. 3. A Stirling engine according to claim 2, A Stirling engine comprising: an opening / closing valve in a working fluid path connecting the low-temperature chamber of the cylinder and the cooler heat exchanger; and when the engine is stopped, the opening / closing valve partially closes the working fluid path.

8. 3. A Stirling engine according to claim 2, a bypass path connecting the low-temperature chambers of the plurality of cylinders that are out of phase with each other by 180°; a communication valve provided in the bypass path, 2. A Stirling engine comprising: a first connecting valve for connecting a first passage of a first fuel cell to a second passage of a second fuel cell; a second connecting valve for connecting a first passage of a first fuel cell to a second passage of a second fuel cell;

9. 8. A Stirling engine according to claim 7, A Stirling engine characterized in that the engine output can be adjusted by controlling the opening and closing valve to an arbitrary opening degree during engine operation.

10. 9. A Stirling engine according to claim 8, A Stirling engine characterized in that the engine output can be adjusted by controlling the opening of the communication valve to an arbitrary degree during engine operation.

11. 9. A Stirling engine according to claim 8, It has a starter motor for starting the engine, A Stirling engine characterized in that, when starting the engine, the starter motor is started with the communication valve open, and after the engine has started, the communication valve is closed and the starter motor is stopped.

12. A Stirling engine according to any one of claims 1 to 11, A Stirling engine, wherein the regenerator is included in the engine body.

13. A Stirling engine according to any one of claims 1 to 12, A Stirling engine, wherein each of the connecting pipes constituting the connecting pipe section has a heat storage body provided inside the connecting pipe wall throughout the entire pipe passage.

14. 14. A Stirling engine according to claim 13, A Stirling engine, wherein the heat storage body has a hollow central portion.

15. A Stirling engine according to any one of claims 1 to 14, A Stirling engine, wherein the connecting pipe portion is detachable from the engine body and the heater structure, and a metal O-ring is disposed on a sealing surface between the connecting pipe portion and the connected members.

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