JP2010144520A - External combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power that is needed to push a piston back to a top dead center. <P>SOLUTION: A section of a container between a cooling part and an expander is branched into a main pipe part 12a and a subpipe part 12b. The expander includes a main piston 17 that displaces in response to a pressure from an operating medium in the main pipe part, and a subpiston 22 that displaces in response to a pressure from an operating medium in the subpipe part. If a position where the main piston is at the closest position to a heating part side, is the top dead center of the main piston, a position where the subpiston is at the closest position to the heating part side, is top dead center of the subpiston, and a position where a liquid part of the operating medium is at the closest position to the heating part side, is an operating medium top dead center, a timing for the subpiston to reach the top dead center is retarded from a timing for the main piston to reach the top dead center, and a timing for the operating medium to reach the top dead center is between the timings for the main piston to reach the top dead center and the subpiston to reach the top dead center. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an external combustion engine that converts a displacement of a liquid portion of a working medium caused by generation and liquefaction of a working medium into mechanical energy and outputs the mechanical energy.

  Conventionally, this type of external combustion engine is disclosed in Patent Document 1. In this prior art, a tubular container in which a working medium is flowably enclosed in a liquid state, and a heater that is disposed on one end side of the container and generates a vapor of the working medium by heating a part of the working medium And a cooler that is disposed on the other end side of the heater in the container and cools and liquefies the vapor of the working medium, and is disposed at the other end of the container and is generated by generation and liquefaction of the vapor of the working medium. And an output unit that converts the displacement of the liquid portion of the working medium into mechanical energy and outputs the mechanical energy.

  The output unit includes a cylinder that communicates with the other end of the container, a piston that is slidably supported by the cylinder, a crank mechanism that is coupled to the piston, and a flywheel that is attached to the crank mechanism. .

  The operation in this prior art will be briefly described. First, the working medium in the liquid state is heated by the heating unit, which is the part of the container where the heater is disposed, to generate the steam of the working medium. Due to the pressure increase, the liquid level of the working medium is pushed down to the output unit side, and the liquid part of the working medium is pushed out to the output unit side.

  The liquid portion of the working medium pushed out to the output unit side presses and pushes the piston of the output unit to displace the piston. This displacement of the piston is converted into rotational motion by the crank mechanism, and the flywheel is rotationally driven.

  Next, when the vapor of the working medium enters the cooling part of the container where the cooler is disposed, the steam is cooled and liquefied by the cooler, so that the pressure drops and the force pushing the piston disappears. . For this reason, since the piston once pushed out is pushed back by the inertia (inertial force) of the flywheel, the liquid portion of the working medium once pushed out is pushed back together with the piston to the heater side.

Since the piston reciprocates by repeating such an operation, the displacement of the liquid portion of the working medium caused by the generation and liquefaction of the working medium vapor is converted into mechanical energy and output.
JP 2004-84523 A

  In the above prior art, when the piston is pushed back, the liquid part of the working medium is also pushed back to the heater side. Therefore, when the piston is pushed back most and reaches the top dead center, the liquid part of the working medium also moves to the most heater side. It is pushed back and reaches top dead center. In other words, in the above prior art, the top dead center of the piston and the top dead center of the liquid portion of the working medium coincide.

  In the above prior art, since the liquid portion of the working medium enters the heating portion of the container immediately before reaching the top dead center, the liquid portion of the working medium is heated immediately before the liquid portion of the working medium reaches the top dead center. Steam is generated and the pressure of the working medium increases.

  This will be described in detail with reference to FIG. FIG. 7 is an example of a timing chart showing the relationship between the crank angle and the pressure of the working medium in the prior art. In the example of FIG. 7, the crank angle when the piston is at the top dead center is 180 deg.

  In the above prior art, the top dead center of the piston coincides with the top dead center of the working medium, and the working medium vapor is generated immediately before the working medium reaches the top dead center. Therefore, as shown in the hatched area of FIG. The pressure of the working medium will increase immediately before the piston reaches top dead center.

  For this reason, in the above prior art, since the piston must reach the top dead center against the pressure of the working medium, the power required to push the piston back to the top dead center becomes large, and as a result, the output decreases. There is a problem of inviting.

  In view of the above points, an object of the present invention is to reduce the power required to push the piston back to top dead center.

In order to achieve the above object, in the invention described in claim 1, tubular containers (12, 121 to 125) in which the working medium (11, 111 to 115) is encapsulated so as to be able to flow in a liquid state;
A heating unit (12a, 121a to 125a) that is formed in a portion on one end side of the container and generates a vapor of the working medium by heating a part of the working medium in the container;
A cooling part (12b, 121b to 125b) that is formed in a part on the other end side of the heating part in the container and cools and liquefies the vapor in the container;
An expander (15, 30) disposed at the other end of the container, which converts the displacement of the liquid portion of the working medium into mechanical energy and outputs the mechanical energy.
The part between the cooling part and the expander in the container is formed by branching into a main pipe part (12a, 121a to 125a) and a sub pipe part (12b, 121b to 125b),
The expander includes a main piston (17, 331 to 335) that is displaced by receiving pressure from the working medium of the main pipe portion, and a sub piston (22, 341 to 345) that is displaced by receiving pressure from the working medium of the sub pipe portion. Have
The position when the main piston is displaced to the most heated part side is the main piston top dead center,
The position when the sub piston is displaced to the most heating side is the sub piston top dead center,
When the position when the liquid part of the working medium is displaced to the most heating part side is the top dead center of the working medium,
The secondary piston top dead center timing is later than the main piston top dead center timing,
The working medium top dead center timing is between the main piston top dead center timing and the sub piston top dead center timing.

  According to this, since the timing of the top dead center of the working medium can be made later than the timing of the top dead center of the main piston, it is possible to suppress the pressure rise of the working medium from starting before the main piston reaches the top dead center ( (See FIG. 3A described later).

  For this reason, it is possible to prevent the main piston from reaching the top dead center due to the increase in the pressure of the working medium, and therefore it is possible to reduce the power for pushing the main piston back to the top dead center.

In the invention according to claim 2, in the external combustion engine according to claim 1, the expander has a conversion member (19, 36) for converting the linear motion of the main piston and the linear motion of the auxiliary piston into rotational motion. And
The conversion member minimizes the conversion efficiency for converting the linear piston linear motion to rotational motion at the timing of the main piston top dead center, and the conversion efficiency for converting the secondary piston linear motion to rotational motion is It is configured to be minimal at timing,
When the position where the main piston is displaced to the opposite side of the heating part is the main piston bottom dead center,
The sub-piston top dead center timing is between the working medium top dead center timing and the main piston bottom dead center timing.

  As a result, the negative output generated from when the pressure of the working medium starts to rise until the sub piston reaches the top dead center can be kept small, so that the sub piston cancels out the output of the main piston. (Refer to FIG. 3 (f) described later).

  The invention according to claim 3 is the external combustion engine according to claim 2, wherein the conversion member is a crankshaft (19) connected to the main piston and the sub piston.

  According to a fourth aspect of the present invention, in the external combustion engine according to the second aspect, the conversion member is a swash plate (36) that is slidably rotated by the linear motion of the main piston and the linear motion of the auxiliary piston. And

  According to a fifth aspect of the present invention, in the external combustion engine according to any one of the first to fourth aspects, the expander is configured such that the stroke volume of the main piston is larger than the stroke volume of the sub-piston. It is characterized by.

  Thereby, since the negative output by the sub piston can be suppressed smaller than the positive output of the main piston, it is possible to suppress the sub piston from canceling the output of the main piston.

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

(First embodiment)
The first embodiment of the present invention will be described below. FIG. 1 is a cross-sectional view schematically showing the overall configuration of the external combustion engine 10 according to the present embodiment. The external combustion engine 10 according to the present embodiment is used as a drive source of a drive target device, for example, a power generator.

  The external combustion engine 10 includes a container 12 in which a working medium 11 is flowably enclosed in a liquid state, a heater 13 that heats and evaporates a part of the working medium 11 in the container 12, and an operation generated by the heater 13. And a cooler 14 that cools and condenses the vapor of the medium 11. In this example, water is used as the working medium 11, but a refrigerant or the like may be used as the working medium 11.

  The container 12 is a tubular pressure vessel, and a heater 13 is disposed at a portion on one end side thereof, and a cooler 14 is disposed on a portion on the other end side of the heater 13. In this example, the arrangement | positioning site | part of the heater 13 and the cooler 14 is formed in the shape extended in an up-down direction among the containers 12, and the cooler 14 is arrange | positioned under the heater 13. FIG.

  Although the heater 13 of this embodiment exchanges heat with a high-temperature gas (for example, exhaust gas from an automobile), the heater 13 may be configured by an electric heater or the like. Further, the cooling water is circulated in the cooler 14 of the present embodiment. Although not shown, a radiator that dissipates the heat taken by the cooling water from the steam of the working medium 11 is disposed in the circulation circuit of the cooling water.

  It is desirable that the heating unit 12a in the container 12 where the heater 13 is disposed and the cooling unit 12b in which the cooler 14 is disposed in the container 12 are made of materials having excellent thermal conductivity. Then, the part is made of copper or aluminum. In addition, you may form the heater 13 and the cooler 14 integrally in the heating part 12a and the cooling part 12b.

  On the other hand, parts other than the heating part 12a and the cooling part 12b in the container 12 are preferably made of a material having excellent heat insulation properties. In this example, since the working medium 11 is water, the part is made of stainless steel.

  A predetermined volume of gas (for example, air) is sealed at one end of the container 12 (upper end on the heating unit 12a side), thereby securing a space necessary for the working medium 11 to evaporate.

  The part of the container 12 on the other end side than the cooling part 12b is formed in a shape that branches into a main pipe part 12c and a sub pipe part 12d. The distal end portions (end portions opposite to the cooling portion 12b) of the main pipe portion 12c and the sub pipe portion 12d are arranged to face each other. An expander 15 serving as an output unit that converts the displacement of the working medium 11 into mechanical energy and outputs the mechanical energy is disposed between the distal ends of the main pipe part 12c and the sub pipe part 12d.

  In this embodiment, a crank type expander is used as the expander 15. Specifically, the expander 15 includes a main cylinder 16 that communicates with the main pipe portion 12c, a main piston 17 that is slidably supported by the main cylinder 16, a main rod 18 that is coupled to the main piston 17, A crankshaft 19 connected to the rod 18 and a crank housing 20 for housing the crankshaft 19 are provided.

  The expander 15 includes a sub cylinder 21 that communicates with the sub pipe portion 12d, a sub piston 22 that is slidably supported by the sub cylinder 21, and a sub rod 23 that is coupled to the sub piston 22 and the crankshaft 19. Have. The sub cylinder 21, the sub piston 22, and the sub rod 23 are disposed on the back side of the crank housing 20 (the side opposite to the main cylinder 16, the main piston 17, and the main rod 18).

  The crankshaft 19 serves as a conversion member that converts the pressure of the main piston 17 and the pressure of the sub piston 22 into rotational torque. In other words, the crankshaft 19 serves as a conversion member that converts the linear motion of the main piston 17 and the linear motion of the auxiliary piston 22 into rotational motion. The crankshaft 19 is formed such that the phase of the sub piston 22 is retarded by a predetermined angle (108 deg in this example) with respect to the phase of the main piston 17.

  The crankshaft 19 is rotatably supported with respect to the crank housing 20, and one end portion of the crankshaft 19 protrudes from the through hole (not shown) of the crank housing 20 to the outside of the crank housing 20 and is driven via a flywheel (not shown). For example, it is connected to a power generator. A magnet coupling method may be used as a rotation support structure for the crankshaft 19 with respect to the crank housing 20.

  The basic operation in the above configuration will be briefly described. When the heater 13 heats and evaporates the working medium (water) 11, the liquid surface 11 a of the working medium 11 is pushed down by the vapor of the high temperature / high pressure working medium 11.

  The liquid portion of the working medium 11 pushed down by the expansion pressure of the steam is pushed out to the main piston 17 side through the main pipe portion 12c and pushed out to the sub piston 22 side through the sub pipe portion 12d.

  As a result, the main piston 17 and the sub-piston 22 are pushed out in a direction approaching the crankshaft 19, so that the linear motion of the main piston 17 and the sub-piston 22 is transmitted to the crankshaft 19 via the main rod 18 and the sub-rod 23. The crankshaft 19 is rotated counterclockwise in FIG.

  When the liquid surface 11a of the working medium 11 is pushed down into the cooling unit 12b, the steam is cooled and liquefied by the cooler 14, so that the pressure for pushing the liquid part of the working medium 11 toward the crankshaft 19 disappears. On the other hand, the crankshaft 19 is rotated by the inertial force of a flywheel (not shown). For this reason, the main piston 17 and the sub piston 22 are pushed back in the direction away from the crankshaft 19, and the liquid portion of the working medium 11 is pushed back into the heating unit 12a.

  Such an operation is repeatedly executed until the operations of the heater 13 and the cooler 14 are stopped. Meanwhile, the liquid portion of the working medium 11 in the container 12 is periodically displaced (so-called self-excited vibration), and the main piston 17 and the sub piston 22 are driven to reciprocate, and the crankshaft 19 is continuously rotated. As a result, the self-excited vibration of the liquid portion of the working medium 11 can be extracted as the rotational movement of the crankshaft 19.

  In the present embodiment, as described above, the phase of the sub piston 22 is retarded by a predetermined angle (108 deg in this example) with respect to the phase of the main piston 17, so that the phase of the self-excited vibration of the liquid portion of the working medium 11. Is intermediate between the phase of the main piston 17 and the phase of the sub-piston 22.

  The phase relationship between the main piston 17, the sub piston 22, and the working medium 11 will be described in detail with reference to FIGS. For convenience of illustration, the reference numerals are omitted in FIG.

  In the following, the position when the main piston 17 is displaced to the most heating part 12a side is referred to as the main piston top dead center (see FIG. 2D), and the main piston 17 is the most opposite to the heating part 12a. The position at the time of displacement is called the main piston bottom dead center (see FIG. 2A).

  Similarly, the position when the sub-piston 22 is displaced to the most heating part 12a side is called the sub-piston top dead center (see FIG. 2 (f)), and the sub-piston 22 is the most opposite to the heating part 12a. The position when displaced is called the sub-piston bottom dead center (see FIG. 2C).

  Further, the position when the liquid portion of the working medium 11 is displaced most toward the heating portion 12a is called the working medium top dead center (see FIG. 2E), and the liquid portion of the working medium 11 is the most heated portion. The position when displaced to the opposite side of 12a is called the working medium bottom dead center (see FIG. 2B).

  2 and 3, the crank angle at the bottom dead center of the main piston is 0 deg. Therefore, the crank angle at the top dead center of the main piston is 180 deg. In this example, since the phase of the sub piston 22 is delayed by 108 deg with respect to the phase of the main piston 17, the crank angle at the sub piston bottom dead center is 108 deg, and the crank angle at the sub piston top dead center is 288 deg. is there.

  In this example, the phase of the working medium 11 is retarded by 54 degrees with respect to the phase of the main piston 17 and advanced by 54 degrees with respect to the phase of the auxiliary piston 22.

  In the state of the crank angle = 0 deg shown in FIG. 2A, the main piston 17 is located at the main piston bottom dead center, but the liquid portion of the working medium 11 is pushed down toward the bottom dead center of the working medium. The sub piston 22 is displaced in a direction in which the sub piston 22 is pushed toward the bottom dead center of the sub piston.

  In the state of crank angle = 54 deg shown in FIG. 2B, the liquid portion of the working medium 11 is located at the bottom dead center of the working medium, but the main piston 17 is pushed back toward the top dead center of the main piston. The sub piston 22 is displaced in a direction in which the sub piston 22 is pushed toward the bottom dead center of the sub piston.

  In the state of crank angle = 108 deg shown in FIG. 2C, the sub piston 22 is located at the sub piston bottom dead center, but the main piston 17 is displaced in a direction to be pushed back toward the main piston top dead center. Thus, the liquid portion of the working medium 11 is displaced in a direction in which it is pushed up toward the top dead center of the working medium.

  In the state of crank angle = 180 deg shown in FIG. 2D, the main piston 17 is located at the top dead center of the main piston, but the liquid portion of the working medium 11 is pushed up toward the top dead center of the working medium. The auxiliary piston 22 is displaced in a direction in which it is pushed back toward the auxiliary piston top dead center.

  In the state of crank angle = 234 deg shown in FIG. 2 (e), the liquid portion of the working medium 11 is located at the top dead center of the working medium, but the main piston 17 is pushed in the direction pushed toward the bottom dead center of the main piston. The auxiliary piston 22 is displaced in a direction in which it is pushed back toward the auxiliary piston top dead center.

  In the state of crank angle = 288 deg shown in FIG. 2 (f), the sub piston 22 is positioned at the top dead center of the sub piston, but the main piston 17 is displaced in the direction pushed toward the bottom dead center of the main piston. Thus, the liquid portion of the working medium 11 is displaced in a direction to be pushed down toward the bottom dead center of the working medium.

  As shown in FIG. 3A, the pressure of the working medium 11 starts to rise immediately before the working medium top dead center, and reaches the maximum pressure in the vicinity of the working medium top dead center. This is because the liquid portion of the working medium 11 enters the heating unit 12a immediately before the top dead center of the working medium. For this reason, the working medium 11 is heated by the heater 13 immediately before the top dead center of the working medium. This is because it is heated and begins to evaporate.

  In the present embodiment, since the phase of the working medium 11 is retarded with respect to the phase of the main piston 17, the timing of the working medium top dead center is later than the timing of the main piston top dead center. For this reason, since the timing at which the pressure of the working medium 11 starts to rise can be delayed, it is possible to suppress the pressure rise of the working medium 11 from starting before the main piston 17 reaches the top dead center.

  For this reason, it is possible to prevent the main piston 17 from reaching the top dead center due to an increase in the pressure of the working medium 11, and therefore it is possible to reduce the power for pushing the main piston 17 back to the top dead center.

  In this example, as shown in the hatched area of FIG. 3A, the pressure of the working medium 11 is increased after the timing of the top dead center of the main piston. For this reason, it can suppress more that the pressure rise of the working medium 11 starts before the main piston 17 reaches a top dead center, and can further reduce the power for pushing the main piston 17 back to the top dead center.

  FIG. 3B shows conversion efficiency (hereinafter referred to as main piston side conversion efficiency) for converting the linear motion of the main piston 17 into the rotational motion of the crankshaft 19 in the crank mechanism 23, and FIG. The conversion efficiency for converting the linear motion of the secondary piston 22 into the rotational motion of the crankshaft 19 in the mechanism 23 (hereinafter referred to as secondary piston-side conversion efficiency) is shown.

  As shown in FIG. 3B, the main piston side conversion efficiency varies depending on the crank angle, and becomes minimum at the bottom dead center and the top dead center of the main piston 17. The reason is as follows.

  First, in the middle of the main piston bottom dead center and the main piston top dead center (crank angle = 90 deg, 270 deg), an action is exerted between the main rod 18 and the crankshaft 19 at a connecting portion between the main rod 18 and the crankshaft 19. Since the direction of the force to rotate and the direction of rotation of the crankshaft 19 are close to parallel, the main piston side conversion efficiency is approximately 1.

  On the other hand, at the bottom dead center and top dead center of the main piston 17 (crank angle = 0 deg, 180 deg), the main rod 18 acts between the main rod 18 and the crankshaft 19 at the connecting portion of the crankshaft 19. This is because the main piston side conversion efficiency becomes zero because the direction of the force is perpendicular to the rotation direction of the crankshaft 19.

  Similar to the main piston side conversion efficiency, the sub piston side conversion efficiency shown in FIG. 3D varies depending on the crank angle, and the sub piston bottom dead center (crank angle = 108 deg) and sub piston top dead center (crank angle = 288 deg). ) To minimize.

  In this example, as can be seen from FIGS. 3A and 3B, when the main piston side conversion efficiency is approximately 1, the pressure of the working medium 11 increases. For this reason, the waveform of the output of the main piston 17 shown in the hatching area M1 in FIG. 3C is substantially the same as the waveform of the pressure of the working medium 11 shown in FIG.

  On the other hand, as shown in the hatching region S1 in FIG. 3E, the sub piston 22 generates a negative output from the start of the pressure of the working medium 11 to the sub piston top dead center. As shown in the hatching area S2 of 3 (e), a positive output is generated from the sub-piston top dead center until the pressure of the working medium 11 drops to atmospheric pressure (1 atm). The reason is as follows.

  That is, as can be seen from FIGS. 3A and 3D, the sub piston 22 is displaced toward the top dead center of the sub piston against the pressure of the working medium 11 when the pressure of the working medium 11 is high. Therefore, a negative output is generated as shown in the hatching area S1 in FIG.

  Further, since the auxiliary piston 22 receives the pressure of the working medium 11 after reaching the auxiliary piston top dead center, the auxiliary piston 22 is displaced toward the auxiliary piston bottom dead center, so that the hatching area S2 in FIG. As shown, a positive output is generated.

  In this example, the secondary piston side conversion efficiency is minimized at the secondary piston top dead center, and the secondary piston top dead center timing is between the working medium top dead center timing and the main piston bottom dead center timing. Therefore, the negative output S1 by the sub piston 22 can be kept small.

  As a result, it is possible to prevent the sub piston 22 from canceling the output of the main piston 17, so that the total output of the main piston 17 and the sub piston 22 is increased as shown by the thick line in FIG. As a result, it is possible to obtain a larger output than before.

(Second Embodiment)
In the first embodiment, a crank type expander is used as the expander 15 forming the output unit. However, in the second embodiment, as shown in FIGS. 4 and 5, a swash plate type is used as the expander 30 forming the output unit. An expander is used.

  FIG. 4 is a schematic diagram showing an outline of the overall configuration of the external combustion engine 10 of the present embodiment, and FIG. 5 is a cross-sectional view showing the expander 30 of FIG. The expander 30 is a five-cylinder type in which first to fifth containers 121 to 125 are connected.

  Each structure of the 1st-5th containers 121-125 is the same as that of the container 12 of the said 1st Embodiment. Specifically, in the first to fifth containers 121 to 125, one end portion where the heaters 131 to 135 and the coolers 141 to 145 are arranged extends in the vertical direction, and the other end portion is the main pipe portion 121c. To 125c and sub-pipe parts 121d to 125d.

  The expander 30 has first to fifth main cylinders 311 to 315 and first to fifth sub cylinders 321 to 325. In FIG. 4, for convenience of illustration, the first to fifth sub cylinders 321 to 325 are illustrated outside the first to fifth main cylinders 311 to 315, but actually, as shown in FIG. The fifth sub cylinders 321 to 325 are disposed on the back side of the expander 30 (the side opposite to the first to fifth main cylinders 311 to 315).

  The connection relationship between the first to fifth containers 121 to 125 and the first to fifth main cylinders 311 to 315 and the first to fifth sub cylinders 321 to 325 of the expander 30 is as shown in FIG.

  Specifically, in the first container 121, the main pipe part 121c is connected to the first main cylinder 311 and the sub pipe part 121d is connected to the fifth sub cylinder 325. The second container 122 has a main pipe portion 122 c connected to the second main cylinder 312 and a sub pipe portion 122 d connected to the first sub cylinder 321.

  The third container 123 has a main pipe portion 123 c connected to the third main cylinder 313 and a sub pipe portion 123 d connected to the second sub cylinder 323. The fourth container 124 has a main pipe portion 124 c connected to the fourth main cylinder 314 and a sub pipe portion 124 d connected to the third sub cylinder 323. The fifth container 125 has a main pipe portion 125 c connected to the fifth main cylinder 315 and a sub pipe portion 125 d connected to the fourth sub cylinder 324.

  As shown in FIG. 5, the first main piston 331 is disposed in the first main cylinder 311, and the fifth main piston 335 is disposed in the fifth main cylinder 315. A first sub piston 341 is disposed in the first sub cylinder 321, and a fifth sub piston 345 is disposed in the fifth sub cylinder 325.

  Although not shown, similarly, the second to fourth main pistons 332 to 334 are also disposed in the second to fourth main cylinders 312 to 314, and the second to fourth sub cylinders 322 to 324 are disposed in the second to fourth sub cylinders 322 to 324. Also, second to fourth auxiliary pistons 342 to 345 are arranged. In addition, about the 2nd-4th main piston 332-334 and the 2nd-4th subpiston 342-345, only the code | symbol is shown in the parenthesis of FIG.

  The first to fifth main pistons 331 to 335 and the first to fifth sub pistons 341 to 345 are configured to slide and rotate a disk-shaped swash plate 35. The swash plate 35 serves as a conversion member that converts the pressure of the first to fifth main pistons 331 to 335 and the pressure of the first to fifth sub pistons 341 to 345 into rotational torque.

  The first to fifth main cylinders 311 to 315 and the first to fifth sub cylinders 321 to 325 are arranged at equal intervals in the rotation direction of the swash plate 35 (clockwise direction in FIG. 4), that is, at intervals of 72 degrees. Accordingly, the phases of the first to fifth main pistons 331 to 335 are shifted by 72 degrees, and the phases of the first to fifth auxiliary pistons 341 to 345 are also shifted by 72 degrees.

  As shown in FIG. 5, the first sub-piston 341 is configured to be displaced integrally with the first main piston 331. Accordingly, the phase of the first sub piston 341 is shifted by 180 deg from the phase of the first main piston 331 and becomes the opposite phase.

  Similarly, with respect to the second to fifth main pistons 332 to 335 and the second to fifth sub pistons 342 to 345, the sub piston is displaced integrally with the main piston and has a phase opposite to that of the main piston.

  A specific configuration example of the first main cylinder 311 and the first sub cylinder 321 will be described with reference to FIG. The internal space of the first main cylinder 311 communicates with the main pipe portion 121c of the first container 121 and the space filled with the working medium 111 of the first container 121, and the first main piston 331 reciprocates with the working oil 361 sealed therein. It is partitioned by a diaphragm 371 from the space to be operated. In the expander 30, a space 381 for storing a surplus of hydraulic oil 361 is formed.

  The internal space of the first sub-cylinder 321 communicates with the sub-pipe portion 122d of the second container 122 so that the working medium 112 of the second container 122 is filled with the working oil 391 and the first sub-piston 341 reciprocates. It is partitioned by a diaphragm 401 from a moving space. In the expander 30, a space 411 for storing a surplus of hydraulic oil 391 is formed.

  The stroke volume of the first main piston 331 is larger than the stroke volume of the first sub piston 341.

  As shown in FIG. 5, the fifth main cylinder 315 and the fifth sub cylinder 325 can also be configured in the same manner as the specific configuration example of the first main cylinder 311 and the first sub cylinder 321 described above.

  That is, the internal space of the fifth main cylinder 315 communicates with the main pipe portion 125c of the fifth container 125 and the space filled with the working medium 115 of the fifth container 125, the working oil 365 is enclosed, and the fifth main piston 335 is enclosed. It is partitioned by a diaphragm 375 from a reciprocating space. In the expander 30, a space 385 for storing a surplus of the hydraulic oil 365 is formed.

  The internal space of the fifth sub cylinder 325 communicates with the sub pipe portion 121d of the first container 121 and the space filled with the working medium 111 of the first container 121, and the fifth sub piston 345 reciprocates with the hydraulic oil 395 enclosed therein. It is partitioned by a diaphragm 405 from a moving space. In the expander 30, a space 415 for storing a surplus of hydraulic oil 395 is formed.

  The stroke volume of the fifth main piston 335 is larger than the stroke volume of the fifth sub piston 345.

  Although not shown, the second to fourth main cylinders 312 to 314 and the second to fourth sub cylinders 322 to 324 also include the first and fifth main cylinders 311 and 315 and the first and fifth sub cylinders. The cylinders 321 and 325 can be configured similarly to the specific configuration example.

  The swash plate 35 slides with the first to fifth main pistons 331 to 335 and the first to fifth sub pistons 341 to 345 via the shoe 42. The expander 30 has a shaft 43 that transmits the rotational motion of the swash plate 35, and the shaft 43 is connected to a drive target device (for example, a power generation device).

  FIG. 6A is a graph showing the phase relationship between the first main piston 331 and the fifth sub piston 345 that are displaced by the pressure of the working medium 111 in the first container 121 and the working medium 111 in the first container 121. is there.

  In FIG. 6A, the one-dot chain line indicates the phase of the first main piston 331, the two-dot chain line indicates the phase of the fifth sub-piston 345, and the solid line indicates the phase of the working medium 111 of the first container 121. Yes. In FIG. 6A, the phase of the fifth main piston 335 is indicated by a broken line for reference. In FIG. 6A, the rotation angle of the swash plate 35 when the first main piston 331 is located at the top dead center is 0 deg.

  As described above, the fifth sub piston 345 is retarded by 180 deg with respect to the fifth main piston 335, and the fifth main piston 335 is advanced by 72 deg with respect to the first main piston 331. Accordingly, the fifth auxiliary piston 345 is delayed by 108 deg with respect to the first main piston 331.

  Since the first main piston 331 and the fifth sub-piston 345 are displaced by the pressure of the working medium 111 in the first container 121, the phase waveform of the working medium 111 in the first container 121 is the phase of the first main piston 331. And the waveform of the phase of the fifth sub piston 345 are combined.

  Therefore, the phase of the working medium 111 in the first container 121 is retarded by 54 degrees with respect to the phase of the first main piston 331, so that the timing of the working medium top dead center is higher than the timing of the first main piston top dead center. Also later.

  Therefore, similarly to the first embodiment, since it is possible to suppress the pressure increase of the working medium 111 before the first main piston 331 reaches the top dead center, the first main piston 331 is increased by the pressure increase of the working medium 111. Can be prevented from reaching the top dead center, and the power required to push the first main piston 331 back to the top dead center can be reduced.

  For the same reason, the power required to push the second to fifth main pistons back to top dead center can also be reduced.

  FIG. 6B shows the conversion efficiency for converting the linear motion of the first main piston 331 into the rotational motion of the swash plate 35 in the expander 30 (hereinafter referred to as the first main piston conversion efficiency). In the example of FIG. 6B, the inclination angle of the swash plate 35 is 20 deg, and the friction coefficient between the swash plate 35 and the shoe 42 is 0.02.

  As can be seen from FIG. 6B, the first main piston conversion efficiency varies depending on the rotation angle of the swash plate 35, and becomes the minimum at the first main piston top dead center and the first main piston bottom dead center. The reason for this is the same as the reason why the main piston side conversion efficiency in the first embodiment changes as shown in FIG.

  As can be seen from FIGS. 6A and 6B, the working medium 111 reaches the top dead center at the crank angle = 54 deg where the first main piston conversion efficiency is high, and the pressure of the working medium 111 is the highest pressure. become.

  For this reason, since a high pressure can be applied to the first main piston 331 at a phase where the first main piston conversion efficiency is increased, a large output can be obtained by the first main piston 331.

  Also for the second to fifth main pistons, high pressure can be applied to the second to fifth main pistons for the same reason as the first main piston 331 at a phase where the conversion efficiency from linear motion to rotational motion increases. .

  In addition, since the stroke volume of the first to fifth main pistons 331 to 335 is larger than the stroke volume of the first to fifth sub pistons 341 to 345, it is negative by the first to fifth sub pistons 341 to 345. An output can be restrained small compared with the plus output of the 1st-5th main pistons 331-335.

  As a result, similar to the first embodiment, it is possible to suppress the sub pistons 341 to 345 canceling the outputs of the main pistons 331 to 335 and to make the total output positive. Large output can be obtained.

(Other embodiments)
In the first embodiment, the example in which the phase difference between the sub piston 22 and the working medium 11 is set to 54 deg has been described. However, if the phase difference between the sub piston 22 and the working medium 11 is made smaller than 54 deg, the sub piston 22 and the working medium 11 have a sub phase difference. Negative output S1 by the piston 22 can be further reduced.

  Moreover, in each said embodiment, although the arrangement | positioning site | part of the heater 13 and the cooler 14 is formed in the one tubular shape among the containers 12, even if the said site | part of the container 12 is formed in the several branched tubular shape. Good.

  Moreover, in each said embodiment, although the arrangement | positioning site | part of the heater 13 and the cooler 14 is extended in the up-down direction among the containers 12, the vapor | steam of the working medium 11 generated by the heater 13 does not flow to the expander 15. For example, the part of the container 12 may extend in a direction inclined with respect to the vertical direction or in the horizontal direction.

It is sectional drawing which shows the whole structure of the external combustion engine in 1st Embodiment of this invention. It is explanatory drawing which shows the action | operation of the external combustion engine of FIG. It is explanatory drawing which shows the phase relationship of the main piston of the external combustion engine of FIG. 1, a subpiston, and a working medium. It is a schematic diagram which shows the whole structure of the external combustion engine in 2nd Embodiment of this invention. It is sectional drawing which shows the expander of the external combustion engine of FIG. It is explanatory drawing which shows the phase relationship of the 1st main piston of the external combustion engine of FIG. 4, a 5th sub piston, and a working medium. It is explanatory drawing which shows the relationship between the crank angle and pressure of a working medium in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Working medium 12 Container 12a Heating part 12b Cooling part 12c Main pipe part 12d Sub pipe part 15 Expander 17 Main piston 19 Crankshaft (conversion member)
22 Secondary piston

Claims (5)

Tubular containers (12, 121-125) in which the working medium (11, 111-115) is encapsulated so as to be able to flow in a liquid state;
A heating unit (12a, 121a to 125a) that is formed in a portion on one end side of the container and generates a vapor of the working medium by heating a part of the working medium in the container;
A cooling unit (12b, 121b to 125b) that is formed in a portion of the container on the other end side than the heating unit and cools and liquefies the vapor in the container;
An expander (15, 30) disposed at the other end of the container and converting the displacement of the liquid portion of the working medium into mechanical energy and outputting the mechanical energy.
The part between the cooling part and the expander in the container is formed by branching into a main pipe part (12a, 121a to 125a) and a sub pipe part (12b, 121b to 125b),
The expander includes a main piston (17, 331 to 335) that is displaced by receiving pressure from the working medium in the main pipe portion, and a sub piston (22, that is displaced by receiving pressure from the working medium in the sub pipe portion). 341-345)
The position when the main piston is displaced to the most heating part side is the main piston top dead center,
The position when the sub-piston is displaced most to the heating part side is the sub-piston top dead center,
When the position when the liquid part of the working medium is displaced to the most heating part side is the working medium top dead center,
The timing of the sub-piston top dead center is later than the timing of the main piston top dead center,
The external combustion engine characterized in that the timing of the top dead center of the working medium is between the timing of the top dead center of the main piston and the timing of the top dead center of the sub piston. The expander has a conversion member (19, 36) for converting the linear motion of the main piston and the linear motion of the sub-piston into rotational motion,
The conversion member has a minimum conversion efficiency for converting the linear motion of the main piston to a rotational motion at the timing of the top dead center of the main piston, and a conversion efficiency for converting the linear motion of the secondary piston to a rotational motion is the secondary motion. It is configured to be minimized at the timing of the top dead center of the piston,
When the position when the main piston is displaced to the side opposite to the heating part is the main piston bottom dead center,
The external combustion engine according to claim 1, wherein the timing of the top dead center of the sub piston is between the timing of the top dead center of the working medium and the timing of the bottom dead center of the main piston.   The external combustion engine according to claim 2, wherein the conversion member is a crankshaft (19) connected to the main piston and the sub-piston.   The external combustion engine according to claim 2, wherein the conversion member is a swash plate (36) that is slidably rotated by a linear motion of the main piston and a linear motion of the sub-piston.   The external combustion engine according to any one of claims 1 to 4, wherein the expander is configured such that a stroke volume of the main piston is larger than a stroke volume of the sub-piston.

Images