JP5632187B2 - Heat engine - Google Patents

Description

  In the present invention, a regenerator as a boundary of the temperature range is provided in a space in which the working gas having different temperature ranges is held, and the volume change of the high temperature space and the low temperature space on both sides of the regenerator and movement of the working gas are provided. The present invention relates to a heat engine that converts heat and power using, for example, a Stirling cycle.

  The Stirling cycle is characterized by the fact that not only combustion heat sources but also heat sources with various temperature differences such as waste heat and solar heat can be used. It is necessary to optimize the balance between the volume change and the regenerator passing gas flow rate according to the temperature difference.

  In a low temperature difference heat source such as waste heat or solar heat, it is necessary to increase the ratio of the regenerator passing gas flow rate compared to the volume change amount. This is because the source of the output of the Stirling cycle is the increase in pressure of the gas when passing through the regenerator, and if the temperature difference is small, the increase in pressure with respect to the gas flow rate is reduced. Therefore, if the maximum output is to be output from the low temperature difference heat source, it is necessary to increase the regenerator passage gas flow rate with respect to the volume change amount as compared with the case where the high temperature difference heat source is used (for example, Patent Document 1 below). reference).

JP 2006-118430 A

  As described above, particularly in the Stirling cycle using the low temperature difference heat source, it is necessary to increase the regenerator passage gas flow rate with respect to the volume change amount as compared with the case where the high temperature difference heat source is used.

  Therefore, an object of the present invention is to ensure a sufficient pressure change by increasing the regenerator passage gas flow rate when using a low temperature difference heat source.

The present invention provides a regenerator as a boundary of the temperature range in a working space in which working gases having different temperature ranges are held, and changes in volume of the high temperature space and the low temperature space on both sides of the regenerator and the working gas. In a heat engine that performs conversion between heat and power using movement, a first piston is provided that changes the volume of the working space and transmits power in response to a pressure change of the working gas. respectively the second and third piston to move between the hot space and the cold space, the low-temperature space and high temperature space and configured for moving a phase difference of 180 degrees from each other with respect to the regenerator One of the second and third pistons is movably accommodated in a cylinder portion provided in the first piston, and the first piston and the second and third pistons are smaller than 180 degrees. Characterized by being configured for moving in phase difference.

  According to the present invention, the first piston that changes the volume of the working gas and transmits the power by receiving the pressure change of the working gas in the working space in which the working gases having different temperature ranges are held, and the working By providing the second and third pistons that move the gas between the high temperature space and the low temperature space, it is possible to ensure the necessary regenerator passing gas flow rate according to the temperature difference and to ensure sufficient pressure change. it can.

  In addition, the displacer is configured with the second and third pistons facing each other. By connecting them with connecting rods, movement with a phase difference of 180 degrees relative to the regenerator can be achieved, and a large area piston is used. Even so, the pressure change of the working gas can be absorbed by the connecting rod, and the piston force acting on the crankshaft can be kept small. Therefore, the shaft diameter of the crankshaft can be kept small.

It is sectional drawing seen from the axial direction of the crankshaft of the heat engine which shows the 1st Embodiment of this invention. It is AA sectional drawing of FIG. It is sectional drawing seen from the axial direction of the crankshaft of the heat engine which shows the 2nd Embodiment of this invention. It is BB sectional drawing of FIG. It is sectional drawing seen from the axial direction of the crankshaft of the heat engine which shows the 3rd Embodiment of this invention. It is CC sectional view of FIG. It is sectional drawing corresponding to FIG. 2 which shows the 4th Embodiment of this invention. It is sectional drawing corresponding to FIG. 1 which shows a reference example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
1 and 2 show a Stirling engine as a heat engine having a Stirling cycle according to the first embodiment of the present invention. A cover 3 is provided in the upper opening of the housing body 1 and a crankcase 5 is provided in the lower opening to constitute a housing 7.

  In each drawing used in the following description including FIG. 1 and FIG. 2, the three members of the housing main body 1, the cover 3, and the crankcase 5 are shown as an integrated unit for the sake of simplicity. ing.

  A heat exchanger unit 9 is accommodated and fixed in the heat exchanger housing portion 1a at the center in the vertical direction in the figure of the housing body 1. The heat exchanger unit 9 is provided with a regenerator 11 as a boundary between different temperature ranges at the center, and a heat absorber 13 and a radiator 15 on both upper and lower sides.

  The heat absorber 13 includes a heat transfer tube 13a extending in a direction orthogonal to the paper surface in FIG. 2, and a high-temperature heat transfer fluid flows through the outside of the heat exchanger housing portion 1a in the heat transfer tube 13a. Wears multiple fins. Similarly, the radiator 15 includes a heat transfer tube 15a extending in a direction orthogonal to the paper surface in FIG. 2, and a low-temperature heat transfer fluid flows through the outside of the heat exchanger housing portion 1a in the heat transfer tube 15a. A plurality of fins are attached around. On the other hand, the regenerator 11 is formed by laminating a wire mesh or the like.

  A high temperature side cylinder portion 1b is formed in the housing body 1 located on the upper side of the heat absorber 13 in the drawing, and a third piston (corresponding to the other piston) is formed in the high temperature space 17 in the high temperature side cylinder portion 1b. The first displacer 19 is accommodated so as to be movable in the vertical direction in the figure. On the other hand, a low temperature side cylinder portion 1c is formed in the housing body 1 located on the lower side of the radiator 15 in the figure, and a power piston 21 as a first piston is shown in the low temperature space 20 in the low temperature side cylinder portion 1c. It is housed so that it can move vertically. Piston rings 23 and 25 are mounted on the outer circumferences of the first displacer 19 and the power piston 21, respectively.

  The first displacer 19 and the power piston 21 have the same outer diameter. The heat exchanger unit 9 positioned between the first displacer 19 and the power piston 21 is formed so as to protrude radially outward from the outer peripheral surfaces of the first displacer 19 and the power piston 21. As viewed (viewed from above and below in FIGS. 1 and 2), the shape is substantially square. At that time, the outer peripheral edge of the heat exchanger unit 9 is inserted and disposed in a recess 1 d formed corresponding to the heat exchanger housing part 1 a of the housing body 1.

  A cylinder portion 21 a serving as a piston accommodating portion is formed on the side of the power piston 21 facing the heat exchanger unit 9, and the cylinder portion 21 a has a second outer diameter smaller than that of the first displacer 19. A second displacer 27 as a piston (corresponding to one piston) is accommodated so as to be movable in the vertical direction in the figure. A piston ring 29 is attached to the outer periphery of the second displacer 27.

  The first displacer 19 and the second displacer 27 are connected to each other by a connecting rod 31 penetrating through a through hole 9a provided in the center of the heat exchanger unit 9 so as to be movable in the axial direction (vertical direction in FIG. 1). doing. The second displacer 27 is connected to a crankshaft 33 rotatably accommodated in the crankcase 5 via a single connecting rod 35.

  Accordingly, when one of the first displacer 19 and the second displacer 27 is located at the top dead center, the other is located at the bottom dead center, and the phase difference of 180 degrees relative to the heat exchanger unit 9 is obtained. It consists of two pistons that move in

  On the other hand, the power piston 21 is connected to the crankshaft 33 via the two connecting rods 37 so as to move with a phase difference smaller than 180 degrees relative to the first displacer 19, for example, a phase difference of 90 degrees. .

  Here, the power piston 21 including the cylinder part 21a includes a cylindrical peripheral wall part 21b, a disk-shaped bottom wall part 21c, and a heat exchanger unit 9 on the opposite side of the peripheral wall part 21b from the bottom wall part 21c. And a piston top portion 21d located at a position opposite to.

  A connecting tool 39 attached to the center of the lower surface of the second displacer 27 is inserted into the through hole 21c1 provided in the center of the bottom wall portion 21c so as to be movable in the vertical direction in the figure, and attached to the connecting tool 39. The small end portion 35a of the connecting rod 35 is rotatably connected to the piston pin 41.

  Further, as shown in FIG. 2, a boss portion 21e protruding toward the crankshaft 33 is formed at a position corresponding to the crankshaft 33 on the outer peripheral side of the bottom wall portion 21c of the power piston 21, and this boss portion is formed. The small end portion 37a of the connecting rod 37 is rotatably connected to a piston pin 43 provided on 21e.

  The large ends 35b and 37b of the connecting rod 35 and the two connecting rods 37 are formed in an annular shape, and are formed eccentrically with respect to the crankshaft 33 in the annular large ends 35b and 37b. The eccentric disc parts 33a and 33b are connected rotatably.

  As described above, the rotation of the crankshaft 33 causes the first and second displacers 19 and 27 to move with a phase difference of 180 degrees through the one connecting rod 35 and simultaneously through the two connecting rods 37. The power piston 21 moves with respect to the first displacer 19 with a phase difference smaller than 180 degrees, for example, a phase difference of 90 degrees.

  The high-temperature space 17 in which the working gas heated by the heat absorber 33 expands between the heat absorber 13 and the first displacer 19 is between the heat radiator 15, the second displacer 27, and the power piston 21. The above-described low-temperature spaces 20 are formed in which the working gas radiated by the radiator 15 is compressed. Between the high temperature space 17 and the low temperature space 20, the working gas is moved and the expansion and compression of the working gas are repeated to convert heat and power.

  Here, a region surrounded by the housing main body 1, the first displacer 19, and the power piston 21 is a working space in which a working gas such as helium is sealed in a sealed state. At this time, the power piston 21 has a function of changing the volume of the working gas with respect to the low temperature space 20 and transmitting power by receiving a pressure change of the working gas. On the other hand, the first and second displacers 19 and 27 have a function of moving the working gas between the high temperature space 17 and the low temperature space 20.

  Since the first and second displacers 19 and 27 have different outer diameters, they function not only as a displacer but also as a power piston that causes a volume change.

  The reciprocating motion of the power piston 21 based on the pressure change of the working gas is taken out as a rotational motion by the crankshaft 33, so that the present Stirling cycle becomes an engine. By reciprocating the power piston 21, a heat pump or a refrigerator that supplies hot and cold heat to the outside via the heat transfer fluid flowing through the heat transfer tubes 13 a and 15 a that penetrate the heat absorber 13 and the heat radiator 15 is obtained.

  In the Stirling cycle according to the first embodiment described above, when the first displacer 19 and the second displacer 27 reciprocate with a phase difference of 180 degrees with respect to the heat exchanger unit 9, the power piston 21 reciprocates. As a result, the volume of the working space is changed. For this reason, the high temperature space 17 and the low temperature space 20 are substantially equivalent to a volume change with a phase difference other than 180 degrees.

  Heat and power are converted by the expansion and compression of the working gas due to the volume change of the working space. At this time, the working gas passes through the heat absorber 13, the regenerator 11 and the radiator 15 as a reciprocating flow sequentially. At the same time, the heat absorber 13 and the radiator 15 perform heat exchange, and at the same time, the working gas passing through the regenerator 11 is moved.

  In this case, in the present embodiment, the power piston 21 that causes the working space in which the working gases having different temperature ranges are held to change the volume of the working gas and transmits the power by receiving the pressure change of the working gas, and By providing the first and second displacers 19 and 27 for moving the working gas between the high-temperature space 17 and the low-temperature space 20, a necessary regenerator passage gas flow rate corresponding to the temperature difference can be ensured and sufficient. A pressure change can be secured.

  Thus, when changing the volume of the high temperature space 17 and the low temperature space 20 with a phase difference of substantially 150 degrees other than 180 degrees, the stroke volume of the power piston 27 is that of each displacer 19, 27. Since it is smaller, the phase difference of the volume change between the high temperature space 17 and the low temperature space 20 can be substantially increased. Accordingly, the power piston 21 may be connected to the crankshaft 33 so as to be movable relative to the first displacer 19 with a phase difference of 90 degrees. Therefore, the setting of the crankshaft 33 is easy, and the low temperature difference Even in a Stirling cycle of a mold, it is possible to easily obtain a maximum output that is theoretically equivalent to a high temperature difference mold.

  Further, in this case, even if the heat exchanger unit 9 is thinned to increase the surface area and reduce the size, the phase difference between the first displacer 19 and the second displacer 27 with respect to the heat exchanger unit 9 is 180 degrees, that is, each Since the displacers 19 and 27 are configured to move together, the movement of the working gas between the high temperature space 17 and the low temperature space 20 becomes more reliable, and the flow resistance and pressure loss are also reduced. , High speed rotation becomes easy. Achievement of high rotation and compactness is particularly suitable for low temperature difference type Stirling engines that can effectively use natural energy such as geothermal heat and industrial waste heat.

  In the Stirling cycle according to the first embodiment described above, the pressure receiving area by the piston top portion 21d of the power piston 21 is made smaller than the pressure receiving area of the first displacer 19 by forming the cylinder portion 21a therein. At that time, as the support structure of the power piston 21, the two connecting rods 37 are connected and supported at two locations on the outer peripheral side, thereby supporting the support more reliably while suppressing the complication of the structure even with a small pressure receiving area. can do.

  In the present embodiment, the first and second displacers 19 and 27 formed by two pistons are connected to each other by the connecting rod 31. For this reason, the piston force applied to the first displacer 19 and the second displacer 27 is absorbed by the connecting rod 31, and only the area difference between the displacers 19 and 27 acts on the crankshaft 33. Therefore, the mechanical loss is reduced and high-speed rotation is achieved. Becomes easy.

  At this time, in the present embodiment, the first and second displacers 19 and 27 constituted by two pistons are connected to each other by a single connecting rod 31 at their centers. Here, the first displacer 19 on the expansion side has a higher temperature (for example, 300 ° C.) than the second displacer 27 on the compression side, so that a difference in thermal expansion occurs between the first displacer 27 and the second displacer 27.

  However, since the centers of the first and second displacers 19 and 27 are connected by one connecting rod 31, the inclination of the connecting rod 31, the through-hole 9 a of the connecting rod 31 and the heat exchanger unit 9, and Interference or sliding resistance between components, such as between, is suppressed, and the reciprocating motion of the first and second displacers 19 and 27 is also efficiently performed with reduced frictional resistance.

  In addition, since there is only one connecting rod 31, the assembly error is reduced accordingly, the assembly workability is improved, the number of parts is reduced, the processing accuracy requirement is reduced, and the cost is reduced. .

  For example, in the heat engine of the reference example shown in FIG. 8, two displacers 101 and 103 are connected to each other by two connecting rods 105 and 107. In this case, the power piston 109 is accommodated in the cylinder portion 103 a formed on the one displacer 103.

  As described above, in the configuration in which the two displacers 101 and 103 are connected by the two connecting rods 105 and 107, the distance between the connecting rods 105 and 107 becomes non-uniform due to the difference in thermal expansion between the two displacers 101 and 103. Accordingly, the connecting rods 105 and 107 are inclined. As a result, there is a risk that components such as between the connecting rods 105 and 107 and the through hole 9a of the heat exchange unit 9 may interfere with each other or increase sliding resistance.

[Second Embodiment]
In the second embodiment, as shown in FIGS. 3 and 4, the outer diameter of the power piston 21A corresponding to the power piston 21 of FIG. 1 is made larger than that of the power piston 21 of FIG. The outer diameter of the power piston 21A is made larger than the outer diameter of the first displacer 19. For this reason, the diameter of the low temperature side cylinder part 1c of the housing main body 1 which accommodates the power piston 21A is larger than the same diameter of FIG. 1, and the crankcase 5 is also correspondingly large.

  In the second embodiment, the outer diameter of the power piston 21 may be left as it is in the structure of FIG. 1, and the outer diameter of the first displacer 19 may be made smaller than the outer diameter of the power piston 21.

  Other configurations are the same as those of the first embodiment, and the same reference numerals are given to the same components as those of the first embodiment. However, “A” is added to the reference numerals in FIG. 1 for each part of the power piston 21A.

  Here, the power piston 21 is connected to the crankshaft 33 by the two connecting rods 37, but the first displacer 19 is connected to the crankshaft 33 by the single connecting rod 35. For this reason, when the power piston 21 and the first displacer 19 have the same diameter, the piston force acting on them is equivalent, and the drive system of the first and second displacers 19 and 27 is changed to the drive system of the power piston 21. In comparison, the burden is twice as large.

  However, in the present embodiment, by making the outer diameter of the power piston 21A larger than the outer diameter of the first displacer 19, the piston force borne by the power piston 21A can be relatively increased, and the first and second displacers 19, 27 can reduce the piston force acting on both.

  Here, assuming that the area of the power piston = C × (the area of the first displacer−the area of the second displacer) and C = the number of support points of the power piston / the number of support points of the displacer, the load at each support point can be made equal. it can.

  Therefore, in this case, the piston force acting on both the first and second displacers 19 and 27 and the piston force acting on the power piston 21A can be more balanced, and the force acting on one connecting rod 35 can be increased. It can be reduced more.

  In particular, by making the outer diameter of the power piston 21A larger than the outer diameter of the first displacer 19, and further making the outer diameter of the second displacer 27 smaller than the outer diameter of the first displacer 19 as shown in FIG. The piston force acting on both the first and second displacers 19 and 27 and the piston force acting on the power piston 21A can be further balanced.

  In the second embodiment, when the outer diameter of the second displacer 27 is increased to be equal to the outer diameter of the first displacer 19, the first and second displacers 19 and 27 function only as a displacer. That is, the piston force can be applied only to the power piston 21A.

[Third Embodiment]
In the third embodiment, as shown in FIGS. 5 and 6, a second heat exchanger unit 90 is provided on the opposite side of the heat exchanger unit 9 of the first displacer 19 with respect to the structure of FIG. 1 or FIG. 3. The second power piston 210 and the third displacer 270 are disposed on the opposite side of the second heat exchanger unit 90 from the first displacer 19.

  The second power piston 210 includes a cylinder part 210 a corresponding to the cylinder part 21 a of the power piston 21. The third displacer 270 and the first displacer 19 accommodated in the cylinder portion 210a so as to be reciprocally movable are connected to each other by the second connecting rod 310. Accordingly, the first displacer 19, the second displacer 27, and the third displacer 270 reciprocate integrally with each other.

  The power piston 21 here has an outer diameter larger than that of the first displacer 19 like the power piston 21A of the second embodiment, and the outer diameter of the second power piston 210 is the power piston 21. It is equivalent to the outer diameter.

  Here, the outer diameters of the power piston 21 and the second power piston 210 are larger than the outer diameter of the first displacer 19 as described above, and are substantially equal to one side of the heat exchanger units 9 and 90 having a square shape in plan view. The outer peripheral edge portion of each power piston 21, 210 protrudes outward from the outer peripheral edge portions of the first displacer 19 and the heat exchanger units 9, 90.

  The power pistons 21 and 210 of the portion protruding outward are connected to each other by a plurality of, for example, four power piston connecting rods 47. Accordingly, the power pistons 21 and 210 here reciprocate integrally with each other. The four power piston connecting rods 47 are movably inserted into a housing through hole 1a1 formed in the heat exchanger housing part 1a of the housing body 1 so as to penetrate in the vertical direction.

  Accordingly, in the present embodiment, one heat engine unit 49 provided with the first and second displacers 19 and 27 and the power piston 21 respectively, and the first and third displacers 19 and 270 and the second power piston 210 are provided. A plurality of other heat engine units 51 are stacked in the piston moving direction. At this time, the first displacer 19 positioned between the heat engine units 49 and 51 adjacent to each other is shared by the heat engine units 49 and 51.

  When the Stirling cycle is used as an engine cycle while the adjacent heat engine units 49 and 51 share the piston (first displacer 19) and simplify the structure, a standardized module is used. By appropriately stacking, it is possible to easily obtain the required output, and further, by appropriately combining the heat pump cycle and the refrigeration cycle, it is possible to realize a combined cycle corresponding to various heat sources and output temperatures.

In the example of FIG. 5 described above, the two heat engine units 49 and 51 are used. However, it is possible to increase the number to three or four.

  In the example of FIG. 5 described above, the power piston 21 and the second power piston 210 are not connected by the power piston connecting rod 47, and the second power piston 210 is connected to the two connecting rods and the power piston 21 in the same manner as the power piston 21. A crankshaft may be separately set and reciprocated. Even in this case, the power pistons 21 and 210 can move with a phase difference of 180 degrees.

[Fourth Embodiment]
As shown in FIG. 7, the fourth embodiment uses a linear generator unit (or a linear motor) 53 instead of the crankshaft 33 used in each of the above-described embodiments. The linear generator unit 53 includes a linear generator 57 corresponding to the single connecting rod 55 connected to the second displacer 27 and linear generators 61 and 63 corresponding to the two connecting rods 59 connected to the power piston 21. I have.

  Each of these linear generators 57, 61, 63 has the same configuration, and becomes a stator 65 having a coil fixed to the crankcase 5 side, and a movable body movable in the vertical direction in FIG. And a plunger 67. Each plunger 67 is provided integrally with the connecting rods 55 and 59, respectively.

  A spring 71 is provided between the first displacer 19 and a spring receiver 69 provided on the inner surface on the cover 3 side, and a spring 75 is provided between the power piston 21 and a spring receiver 73 provided on the inner surface on the crankcase 5 side. Are provided. Each of these springs 71 and 75 functions to hold the first displacer 19 and the power piston 21 at the neutral position (intermediate position of the piston movement stroke).

  In this case, the power piston 21 and the first and second displacers 19 and 27 reciprocate based on the pressure change of the working gas, so that each plunger 67 reciprocates in the stator 65 and the linear generators 57 and 61. 63 generate electricity. At this time, the springs 71 and 75 are forcibly vibrated to complement the reciprocating motion of the power piston 21 and the first and second displacers 19 and 27. At this time, the first and second displacers 19 and 27 and the power piston 21 are moved with a phase difference of, for example, 90 degrees smaller than 180 degrees as in the above-described embodiments. The masses of the displacers 19 and 27 and the power piston 21 and the spring constants of the springs 71 and 75 are adjusted.

  On the other hand, when the linear generator unit 53 is used as a linear motor, the linear generators 57, 61, 63 become linear motors, and the first and second displacers 19, 27 and the power piston 21 are reciprocated. Thereby, it becomes a heat pump or a refrigerator that supplies warm and cold heat to the outside through the heat transfer fluid flowing in the heat transfer tubes 13a and 15a that penetrate the heat absorber 13 and the radiator 15.

11 Regenerator 17 High-temperature space 19 First displacer (third piston, other displacer)
20 Low temperature space 21, 21A Power piston (first piston)
21a Cylinder part 27 2nd displacer (2nd piston, one displacer)
31 connecting rod 49, 51 heat engine unit 210 second power piston 270 third displacer

Claims (5)

A regenerator is provided as a boundary of the temperature region in a working space in which working gases having different temperature regions are held, and the change in volume of the high and low temperature spaces on both sides of the regenerator and the movement of the working gas are utilized. In the heat engine for converting heat and power, there is provided a first piston that changes the volume of the working space, transmits power in response to a pressure change of the working gas, and converts the working gas to the high-temperature space. the second and third piston to move between a cold space, and configured for moving a phase difference of 180 degrees from each other with respect to the regenerator respectively to the low temperature space and high temperature space, the second And one of the third pistons is movably accommodated in a cylinder portion provided in the first piston, and the first piston and the second and third pistons are operated with a phase difference smaller than 180 degrees. Heat engine, characterized in that set so as to.   The heat engine according to claim 1, wherein the second and third pistons are connected to each other by a connecting rod.   The heat engine according to claim 2, wherein the second and third pistons are connected to each other by a single connecting rod at the center of each piston.   4. The heat engine according to claim 1, wherein a diameter of the first piston is made larger than a diameter of the other of the second and third pistons.   A plurality of heat engine units each including the second and third pistons and the first piston are stacked in the piston moving direction, and each heat engine unit is disposed between adjacent ones of the plurality of heat engine units. The heat engine according to any one of claims 1 to 4, wherein one piston shared with each other is arranged as the other of the second and third pistons.

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