JP4872741B2 - Thermoelectric generator - Google Patents

Description

  The present invention relates to a thermoelectric generator suitable for recovering exhaust heat of an internal combustion engine and generating thermoelectric power, for example.

  2. Description of the Related Art Conventionally, a thermoelectric power generation apparatus that recovers exhaust heat from an internal combustion engine and generates thermoelectric power is generally known. This type of thermoelectric power generation apparatus includes a thermoelectric power generation element module in which a plurality of thermoelectric power generation elements that generate a thermoelectromotive force according to a temperature difference due to the Seebeck effect are PN-connected (see, for example, Patent Document 1).

Here, Patent Document 1 discloses a heat absorption pipe as a heat recovery member through which exhaust gas from an internal combustion engine flows, and a cooling pipe as a heat dissipation member disposed at a predetermined interval outside the heat absorption pipe. A thermoelectric power generation element module configured in an annular shape is disclosed. In this annular thermoelectric power generation module, each thermoelectric power generation element is PN-joined in the circumferential direction, and each thermoelectric power generation element has a high-temperature electrode that is in contact with the outer peripheral surface along the circumferential direction of the heat absorption conduit, It arranges radially between the low-temperature electrodes which contact the inner peripheral surface along the circumferential direction of the cooling pipe.
JP 61-254082 A (FIGS. 2 to 4)

  As described above, in a conventionally known thermoelectric power generation device, each thermoelectric power generation element constituting the thermoelectric power generation element module is arranged radially, and the high temperature end of the thermoelectric power generation element is connected to the outer periphery of the heat absorption pipe line via the high temperature electrode. The curved surface is in contact with the surface, and the low temperature end is in curved contact with the inner peripheral surface of the cooling pipe line via the low temperature electrode. For this reason, when the endothermic pipes that are heat recovery members repeat thermal expansion and contraction in the radial direction due to fluctuations in the amount of exhaust heat according to the operating state of the internal combustion engine, the high temperature end side and the endothermic pipes of each thermoelectric power generation element As a result, the thermoelectric power generation element module may not be able to fully exhibit its thermoelectric power generation capability.

  Therefore, the present invention allows the thermoelectric generator module to fully exhibit its original thermoelectric generation capability even when the heat recovery member thermally expands and contracts in the radial direction due to fluctuations in the amount of heat recovered by the heat recovery member. It is an object of the present invention to provide a thermoelectric generator that can perform the above-described process.

A thermoelectric generator according to the present invention includes a thermoelectric generator module in which a plurality of thermoelectric generators capable of thermoelectric generation are brought into contact with a heat recovery member at a high temperature end side and a low temperature end side is in contact with a heat dissipation member. In the power generation device, the heat recovery member is formed in an annular shape having a flange portion, and is provided on the outer periphery of a pipe through which the exhaust flows. The thermoelectric power generation element module is pressed by the high temperature side against the flange portion of the heat recovery member. It is comprised by the annular | circular shape which is made and is planar contact.

In the thermoelectric power generation device according to the present invention, even when the heat recovery member thermally expands and contracts in the radial direction due to fluctuations in the amount of heat recovered by the heat recovery member, the high temperature side of the thermoelectric power generation element module becomes the flange portion of the heat recovery member. Since the flat contact is ensured, the thermoelectric generation element module sufficiently exhibits its original thermoelectric generation capability.

  In the thermoelectric generator of the present invention, the heat recovery members have a large number of comb-shaped fins arranged radially, and the fins of a pair of adjacent heat recovery members are alternately meshed with a predetermined clearance. It is preferable that the number of fins in the space occupied by the fins is substantially doubled and the heat absorption performance is improved.

In the thermoelectric generator of the present invention, a pair of pressing members that can tilt with respect to each other via a spherical member can be provided as means for pressing the high temperature side of the thermoelectric generator element module against the flange portion of the heat recovery member. . In this case, the thermal expansion of the heat collecting member, when the flange portion of its is tilted by the thermal contraction, the pressing member as the high-temperature side of the thermoelectric power generation element module on the inclined flange portion to follow is tilted, the pressing The high temperature side of the thermoelectric power generation element module pressed by the member is surely brought into flat contact with the flange portion of the heat recovery member.

  According to the thermoelectric generator according to the present invention, even when the heat recovery member thermally expands and contracts in the radial direction due to fluctuations in the amount of heat recovered by the heat recovery member, the high temperature side of the thermoelectric power generation element module is the side surface of the heat recovery member. Therefore, the thermoelectric power generation element module can sufficiently exhibit its original thermoelectric power generation capability.

  Further, when the heat recovery member has a large number of comb-shaped fins arranged radially, and the fins of a pair of adjacent heat recovery members are configured to alternately mesh with each other with a clearance, Since the number of fins in the space occupied by the fins doubles, the heat absorption performance of the heat recovery member can be improved.

  Furthermore, as a means for pressing the high temperature side of the thermoelectric power generation element module against the side surface of the heat recovery member, when it includes a pair of pressing members that can tilt relative to each other via the ball member, the thermal expansion of the heat recovery member, Even when the side surface is inclined due to heat shrinkage, the pressing member tilts so that the high temperature side of the thermoelectric element module follows the inclined side surface, so the high temperature side of the thermoelectric element module pressed by this pressing member is It is possible to make a flat contact with the side surface of the heat recovery member. As a result, even when the side surface of the heat recovery member is inclined due to thermal expansion or contraction, the thermoelectric power generation element module can sufficiently exhibit its original power generation capability.

  Hereinafter, the best embodiment of the thermoelectric generator according to the present invention will be described with reference to the drawings. In the drawings to be referred to, FIG. 1 is a plan view showing a schematic structure of an exhaust system of an internal combustion engine in which a thermoelectric generator according to an embodiment is interposed, and FIG. 2 is a perspective view showing an appearance of the thermoelectric generator shown in FIG. 3 is a side view of the thermoelectric generator shown in FIG. 2, FIG. 4 is a front view of the thermoelectric generator, FIG. 5 is a cross-sectional perspective view showing the internal structure of the thermoelectric generator, and FIG. 6 is the thermoelectric generator. FIG. 7 is a longitudinal sectional view showing the internal structure of the thermoelectric generator.

  A thermoelectric generator according to an embodiment is configured to recover exhaust heat from exhaust gas discharged to an exhaust system of an internal combustion engine mounted on a vehicle and generate thermoelectric power. For this reason, as shown in FIG. 1, a thermoelectric generator 1 according to an embodiment includes, for example, a catalytic converter 3 connected to an exhaust manifold 2 on the exhaust upstream side, an exhaust gas in an exhaust system of an internal combustion engine (not shown), It is interposed between the muffler 4 on the downstream side.

  The electric energy generated by the thermoelectric generator 1 is configured to be charged to the battery 7 via a DC-DC converter 6 that is on / off controlled by an ECU (Electric Control Unit) 5.

  In order to temporarily reduce the amount of heat recovered by the thermoelectric generator 1 in a high-load operation region of the internal combustion engine, such as when the vehicle is running uphill, or to stop heat recovery when the system of the thermoelectric generator 1 is abnormal. In the center of the thermoelectric generator 1, a bypass pipe 8 through which exhaust gas directly circulates from the catalytic converter 3 to the muffler 4 side is installed. A bypass valve 9 that is controlled to be opened and closed by the ECU 5 is attached to the exhaust inlet of the bypass pipe 8.

  Here, as shown in FIGS. 2 to 7, the thermoelectric generator 1 includes a hollow cylindrical cooling water case 10 that constitutes the outer peripheral portion thereof, a cylindrical inflow side housing 11 that constitutes an exhaust inflow portion, an exhaust gas A cylindrical outflow side housing 12 that constitutes the outflow portion, an inflow side bellows tube 13 that covers the inflow side housing 11, an outflow side bellows tube 14 that covers the outflow side housing 12, and the like.

  As shown in FIG. 8, the cooling water case 10 is formed in a hollow cylindrical shape by crimping both ends of the cylindrical outer wall member 10B to both ends of the cylindrical inner wall member 10A. Inside the cooling water case 10, a spiral partition member 10C for forming a spiral cooling water flow path is installed. The cylindrical inner wall member 10 </ b> A and the spiral partition member 10 </ b> C are made of a light aluminum material having a large thermal conductivity and are integrated by brazing. On the other hand, the cylindrical outer wall member 10B is made of a thin steel plate that is not likely to be cracked by stepping stones or the like.

  An inflow nipple 10D through which cooling water flows is fixed to the rear end of the cylindrical outer wall member 10B, and an outflow nipple 10E from which cooling water flows out is fixed to the front end. The inflow side nipple 10D and the outflow side nipple 10E are connected to a cooling water circulation line provided with a cooling water circulation pump 15 and a radiator 16 that are on / off controlled by the ECU 5 shown in FIG. When the pump 15 is ON-controlled by the ECU 5, the cooling water cooled by the radiator 16 circulates through the cooling water case 10.

  At that time, the cooling water flowing into the cooling water case 10 from the inflow side nipple 10D flows through the spiral cooling water flow path formed in the cooling water case 10 by the helical partition member 10C without heat. The entire circumference of the cylindrical inner wall member 10A made of an aluminum material having a high conductivity is reliably cooled.

  As shown in FIGS. 5 to 7, the inflow side housing 11 is a combination of a cylindrical housing body 11 </ b> A and a ring-shaped inflow side holding member 11 </ b> B that is concentrically fitted to the inner end of the housing body 11 </ b> A. A small-diameter ring-shaped support portion 11D is formed on the inner end portion of the housing main body 11A via a plurality of radial connection portions 11C.

  Similarly, a plurality of radial coupling portions 11E and ring-shaped support portions 11F are formed on the inflow-side holding member 11B so as to overlap the radial coupling portions 11C and the ring-shaped support portions 11D of the housing body 11A. The housing body 11A and the inflow side clamping member 11B are supported concentrically on the bypass pipe 8 by the ring-shaped support portion 11D and the ring-shaped support portion 11F slidably fitted on the outer periphery of the bypass pipe 8, respectively. Has been.

  Similarly to the inflow side housing 11, the outflow side housing 12 has a cylindrical housing body 12A having a plurality of radial connection portions 12C and a small diameter ring-shaped support portion 12D, a plurality of radial connection portions 12E, and a small diameter ring shape. A combination structure with a ring-shaped outflow side clamping member 12B having a support portion 12F is adopted. The housing main body 12A and the outflow side clamping member 12B of the outflow side housing 12 are fitted with the ring-shaped support portion 12D and the ring-shaped support portion 12F slidably fitted on the outer periphery of the bypass tube 8, respectively. Are supported concentrically.

  Here, a large diameter portion 8 </ b> A is formed at the front end portion of the bypass pipe 8 facing the inflow side housing 11. A ring-shaped support portion 11F of the inflow-side holding member 11B is locked to the step portion of the large-diameter portion 8A via a ring-shaped support portion 11D of the housing main body 11A constituting the inflow-side housing 11.

  On the other hand, a small diameter portion 8B is formed at the rear end portion of the bypass pipe 8 facing the outflow side housing 12, and a plurality of disc springs 17 and push nuts 18 are attached to the small diameter portion 8B. Then, the screw spring 17 pushes the ring-shaped support portion 12F of the outflow-side clamping member 12B forward through the ring-shaped support portion 12F of the housing body 12A constituting the outflow-side housing 12 by screwing the push nut 18. .

  The inflow side bellows pipe 13 has a connection ring 13A fixed to the outer end thereof fitted and fixed to the outer end of the housing main body 11A of the inflow side housing 11 in an airtight state, and fixed to the inner end thereof. 13B is fitted and fixed to the front end of the cooling water case 10 in an airtight state. Similarly, the connection ring 14A fixed to the outer end of the outflow side bellows tube 14 is connected to the outer end of the housing body 12A of the outflow side housing 12 in an airtight state and fixed to the inner end thereof. The ring 14 </ b> B is connected to the other end of the cooling water case 10 in an airtight state.

  Here, as shown in FIGS. 5 to 7, the side surface of the outer peripheral portion of the inflow side holding member 11 </ b> B constituting the inflow side housing 11 and the side surface of the outer peripheral portion of the outflow side holding member 12 </ b> B constituting the outflow side housing 12. In between, the thermoelectric power generation unit 20 assembled in a donut shape that is slidably fitted to the outer periphery of the bypass pipe 8 and the inner periphery of the cooling water case 10 has, for example, 12 stages from the exhaust inflow side to the exhaust outflow side. is set up.

  As shown in FIG. 5, each thermoelectric power generation unit 20 includes a ring-shaped high-temperature finned heat flow plate 21 fitted to the outer periphery of the bypass pipe 8 as a heat recovery member, and an inner periphery of the cooling water case 10 as a heat radiating member. The ring-shaped low temperature side heat flow plate 22 fitted to the thermoelectric generator element module 23 is interposed between them.

  Here, as shown in FIG. 7, the vicinity of the outer peripheral portion of each high-temperature finned heat flow plate 21 constituting each thermoelectric power generation unit 20 is the outer peripheral portion side surface of the inflow side holding member 11B and the outer peripheral portion of the outflow side holding member 12B. It is sandwiched between the side surfaces with a predetermined pressing load. This pressing load is optimized by adjusting the repulsive force of the disc spring 17 according to the screwing amount of the pressing nut 18 attached to the small diameter portion 8B of the bypass pipe 8.

  Moreover, the outer peripheral surface of each low temperature side heat flow plate 22 constituting each thermoelectric power generation unit 20 is in close contact with the inner peripheral surface of the cooling water case 10 through a silicon grease layer having high thermal conductivity. An appropriate inert gas such as nitrogen gas for preventing oxidation of the thermoelectric power generation element module 23 is placed in the inner space of the cooling water case 10 that is blocked from outside air by the inflow side bellows tube 13 and the outflow side bellows tube 14. Is filled.

  Here, the high-temperature-side finned heat flow plate 21 of the thermoelectric power generation unit 20 is composed of a pair of left and right combined to face each other as shown in an exploded manner in FIG. Each high-temperature finned heat flow plate 21 is integrally formed of heat-resistant insulating ceramics, and has a large-diameter flange portion 21B formed on the outer end side in the left-right direction of the ring-shaped main body 21A, and a main body. It has a large number of comb-shaped fins 21C formed radially arranged on the inner peripheral side of 21A.

  A large number of comb-shaped fins 21C of the high-temperature finned heat flow plates 21 protrude from the main body 21A to the opposite side of the flange portion 21B. A group of oval high temperature side electrodes 23A constituting the thermoelectric generator module 23 are annularly arranged and fitted and joined to the inner surface of the flange portion 21B facing the protruding direction of the numerous fins 21C.

  Such a pair of heat flow plates 21 and 21 with high-temperature fins on the left and right sides have a large number of comb-shaped fins 21C and 21C meshed alternately with a predetermined clearance, and in this state, the main bodies 21A and 21A project. Hit and combine. Then, the comb-shaped fins 21C and 21C of the heat flow plates 21 and 21 with high-temperature fins surround the bypass pipe 8 and are fitted to the outer periphery thereof (see FIG. 5). A predetermined clearance through which exhaust gas flows along the axial direction of the bypass pipe 8 is formed.

  The low-temperature-side heat flow plate 22 of the thermoelectric power generation unit 20 is integrally formed of insulating ceramics, and has a wide annular fitting portion 22A whose outer peripheral surface is fitted to the inner peripheral surface of the cooling water case 10; The peripheral portion has a narrow annular mounting portion 22B facing between the flange portions 21B and 21B of the pair of left and right high-temperature finned heat flow plates 21 and 21.

  A group of floor piston assemblies 24 are annularly arranged and fitted to the mounting portion 22 </ b> B of the low temperature side heat flow plate 22. Further, a group of oval low-temperature side electrodes 23B constituting the thermoelectric power generation element module 23 are respectively fitted in an annular shape on both side surfaces of the mounting portion 22B. A pair of left and right holders 23C, 23C constituting the thermoelectric generator module 23 are mounted on both sides of the low temperature side heat flow plate 22 with the low temperature side electrodes 23B sandwiched between the mounting portions 22B. The

  Each holder 23 </ b> C is made of a soft heat-resistant resin, and is fitted with a flange-like fitting portion 23 </ b> C <b> 1 fitted to the inner peripheral surface of the fitting portion 22 </ b> A of the low-temperature side heat flow plate 22 and the low-temperature side heat flow plate 22. A ring-shaped mounting portion 23C2 that overlaps the side surface of the portion 22B. Then, the low temperature ends of the group of p-type thermoelectric power generation elements P and n-type thermoelectric power generation elements N constituting the thermoelectric power generation element module 23 are fitted and mounted on the mounting portions 23C2 of the respective holders 23C with a slight tightening margin. Thereby, a group of p-type thermoelectric power generation elements P and n-type thermoelectric power generation elements N are alternately arranged in an annular shape. Each holder 23C has a low temperature end of a group of p-type thermoelectric power generation elements P and n-type thermoelectric power generation elements N fitted and mounted on the mounting portion 23C2. There is no problem.

  The thermoelectric generator element module 23 is configured between one high temperature finned heat flow plate 21 and the low temperature side heat flow plate 22, and between the other high temperature side finned heat flow plate 21 and the low temperature side heat flow plate 22. Is also configured. In other words, one thermoelectric power generation unit 20 includes two sets of thermoelectric power generation element modules 23 and 23, and has a configuration of one unit and two modules.

  As shown in FIG. 10, two sets of thermoelectric power generation element modules 23 and 23 configured in each thermoelectric power generation unit 20 are each a group of p-type thermoelectric power generation elements P and n-type thermoelectric power generation elements arranged in an annular shape. N, a group of low-temperature side electrodes 23B that are in PN connection with the low-temperature ends of the group of p-type thermoelectric generators P and n-type thermoelectric generators N, respectively, and a group of p-type thermoelectric generators P and n-type thermoelectrics A group of high-temperature side electrodes 23A that are in contact with the high-temperature end of the power generation element N and are PN-connected are configured in an annular shape.

  Here, as described above, among the thermoelectric power generation units 20 arranged in, for example, 12 stages from the exhaust inflow side to the exhaust outflow side of the thermoelectric power generation apparatus 1, each of the six thermoelectric generation units 20 on the exhaust inflow side The two sets of thermoelectric power generation element modules 23 and 23 respectively configured are connected to each other in series via copper plate wirings 27 whose both ends are connected to the output terminals 25 and 26, and a total of 12 sets of thermoelectric power generation elements. Modules 23 electrically form one group.

  Similarly, two sets of thermoelectric power generation element modules 23, 23 respectively configured in the six-stage thermoelectric power generation units 20 on the exhaust gas outlet side have other copper plate wirings whose both ends are connected to other output terminals 25, 26. 27 are connected in series with each other through a total of twelve sets of thermoelectric generator modules 23 electrically constituting another group.

  Each thermoelectric element module 23 has 30 pairs of p-type thermoelectric elements P and n-type thermoelectric elements N, and 360 pairs of twelve sets of thermoelectric elements 23 constituting one group. Even if the power generation voltage of one PN pair is set to several hundred mV, one group has a thermoelectric power generation capacity of several tens of volts. For this reason, the voltage ratio at the time of voltage conversion by the DC-DC converter 6 shown in FIG. 1 can be made small, and the charging efficiency to the battery 7 is good.

  In this way, the six-stage thermoelectric generation units 20 on the exhaust inflow side electrically constitute one group, and the six-stage thermoelectric generation units 20 on the exhaust outflow side electrically constitute another one group. Therefore, even in the low load operation region where the exhaust heat amount of the internal combustion engine is small, it is possible to reliably generate thermoelectric power by the six thermoelectric power generation units 20 on the exhaust inflow side that can sufficiently absorb the exhaust heat amount. .

  On the other hand, if each of the twelve-stage thermoelectric power generation units 20 electrically constitutes one group, most of the exhaust heat amount is in the exhaust inflow side in the low load operation region where the exhaust heat amount of the internal combustion engine is small. Therefore, each thermoelectric power generation unit 20 on the exhaust outflow side cannot contribute to thermoelectric power generation. In this case, the internal resistance of the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N constituting the thermoelectric power generation element module 23 of each thermoelectric power generation unit 20 on the exhaust gas outlet side, and these, the high temperature side electrode 23A or the low temperature side electrode Since the junction resistance with 23B increases, the thermoelectric generation capability of the thermoelectric generation element module 23 of each thermoelectric generation unit 20 on the exhaust inflow side contributing to thermoelectric generation also decreases.

  The output terminal 25 connected to one end of the copper plate wiring 27 shown in FIG. 10 is airtightly connected to the connection ring 13B in a state of passing through the connection ring 13B of the inflow side bellows tube 13 as shown in FIG. It is fixed. That is, the output terminal 25 is connected to the other insulating collar 29B in which one insulating collar 29A mounted on the outer end is molded in advance on the inner end by screwing a nut 28 screwed into the outer end. The connection ring 13B is sandwiched therebetween so as to be airtightly fixed to the connection ring 13B. A round terminal (not shown) of a lead wire connected to the DC-DC converter 6 shown in FIG. 1 is provided between the nut 28 and one insulating collar 29A at the outer end of the output terminal 25. It is clamped and connected.

  Further, as shown in FIG. 11, an inert gas (for example, nitrogen gas) filled in the space covered with the cooling water case 10 is provided between the opposing surfaces of the main bodies 21 </ b> A and 21 </ b> A of the high-temperature finned heat flow plate 21. A ring-shaped gasket G1 is sandwiched for sealing. Further, a ring for suppressing heat transfer between the opposing surfaces of the flange portions 21B and 21B of the high-temperature finned heat flow plate 21 and between the opposing surfaces of the flange portion 21B and the inflow side holding member 11B of the inflow side housing 11 is provided. A gasket G2 is sandwiched. In addition, the same gasket is clamped also between the opposing surfaces of the outflow side clamping member 12B and the flange part 21B of the outflow side housing 12 which are not illustrated in FIG.

  Here, as shown in FIG. 12, a plurality of oval concave portions 21D into which a group of oval high temperature side electrodes 23A are fitted are formed on the inner surface of the flange portion 21B of each high temperature side finned heat flow plate 21. ing. A plurality of oval concave portions 22C into which a group of oval low temperature side electrodes 23B are fitted are formed on both side surfaces of the mounting portion 22B of the low temperature side heat flow plate 22, respectively. A plurality of piston housing holes 22D into which a group of floor piston assemblies 24 (see FIG. 9) are loosely fitted are opened at both ends of each recess 22C. Is formed.

  Each floor piston assembly 24 has a spherical member 24C sandwiched between spherical recesses 24B (only one shown) formed on the opposing surfaces of a pair of left and right floor pistons 24A, 24A, as shown in an exploded view in FIG. A constructed assembly. Each floor piston 24A has a structure in which piston bodies 24E, 24E made of insulating ceramics are joined to both sides of a low elastic layer 24D made of heat-resistant rubber such as fluoro rubber. On the other hand, the true spherical member 24C is formed into a spherical shape with a material such as stainless steel, aluminum, or ceramics.

  Here, as shown in an enlarged view in FIG. 14, the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N are hard at the high temperature end and the low temperature end, for example, hard such as nickel so as to improve the wear resistance. Plated layers M1 and M2 are formed. Further, at the outer peripheral corners of the hard plating layer M1 at the high temperature end of the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N, the edge load on the high-temperature side electrode 23A is alleviated to reduce the p-type thermoelectric power generation elements P and n-type. In order to prevent the thermoelectric power generation element N from being damaged, crowning of about several μm is applied.

  On the other hand, on the high temperature side electrode 23A, an appropriate insulating layer Z1 is formed except for the surface in contact with the hard plating layer M1 at the high temperature end of the p-type thermoelectric generator P and the n-type thermoelectric generator N. Similarly, an appropriate insulating layer Z2 is formed on the low temperature side electrode 23B except for the surface that contacts the hard plating layer M2 at the low temperature end of the p-type thermoelectric generator P and the n-type thermoelectric generator N. Thereby, the high temperature side finned heat flow plate 21 that contacts the high temperature side electrode 23A via the insulating layer Z1, the low temperature side heat flow plate 22 that contacts the low temperature side electrode 23B via the insulating layer Z2, and the floor pistons 24A and 24A, Each can be made of an appropriate metal material.

  Here, as shown in FIG. 7, each high-temperature finned heat flow of the thermoelectric generation unit 20 in which the vicinity of the outer peripheral portion is sandwiched between the inflow-side clamping member 11B and the outflow-side clamping member 12B with a predetermined pressing load. As shown in FIG. 15, the outer end surfaces of the flange portions 21 </ b> B and 21 </ b> B of two adjacent thermoelectric power generation units 20 are in pressure contact with each other with the gasket G <b> 2. Between the inner end faces of the flange portions 21B and 21B of the pair of high-temperature-side finned heat flow plates 21 constituting one thermoelectric power generation unit 20, two sets of thermoelectric generation elements configured on both sides of the low-temperature side heat flow plate 22 are provided. The modules 23 are sandwiched by a predetermined pressing load through a group of floor piston assemblies 24 loosely fitted in the piston accommodation holes 22D of the low temperature side heat flow plate 22.

  In each thermoelectric power generation unit 20 assembled in this way, the high temperature ends of the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N of the two sets of thermoelectric power generation element modules 23 and 23 are respectively connected to the high temperature side electrodes 23A and 23A. Due to the flat contact, the flanges 21B and 21B of the high-temperature finned heat flow plates 21 and 21 are relatively slidable in the radial direction, and follow the inclination of the inner surfaces of the flanges 21B and 21B. And can be tilted.

  Here, each floor piston assembly 24 presses the low temperature side electrodes 23B, 23B on the low temperature side of the thermoelectric power generation element modules 23, 23 on both sides by a reaction force of a predetermined pressing load, thereby Each of the high temperature side electrodes 23A, 23A functions as means for pressing the flanges 21B, 21B of the high temperature side finned heat flow plates 21, 21 respectively. In this case, each floor piston assembly 24 has a low elastic layer 24D, 24D provided at an intermediate portion between the pair of floor pistons 24A, 24A, which is appropriately expanded and contracted, so that the thermoelectric generator module 23, 23 in the thickness direction. A dimensional error, a dimensional error in the thickness direction of the mounting portion 22B of the low temperature side heat flow plate 22, and the like are absorbed.

  Such a floor piston assembly 24 is loosely fitted in the piston accommodating hole 22D of the low temperature side heat flow plate 22, so that a pair of floor pistons 24A and 24A as pressing members are supported by the true spherical member 24C. Each can be tilted freely. The piston accommodation hole 22D is filled with appropriate heat conduction grease to reduce the resistance of heat flowing from the low temperature side electrodes 23B, 23B to the mounting portion 22B via the floor pistons 24A, 24A.

  In the thermoelectric generator 1 of the present embodiment configured as described above, exhaust gas flows from the inflow side housing 11 to the outflow side housing 12 of the thermoelectric generator 1 with the start of operation of the internal combustion engine of the vehicle (not shown). The pair of high temperature side finned heat flow plates 21 and 21 constituting the thermoelectric power generation unit 20 of each stage collects the exhaust heat by a number of comb-shaped fins 21C. At that time, the pair of high temperature side finned heat flow plates 21 and 21 have a plurality of comb-shaped fins 21C alternately meshing with each other with a predetermined clearance. The heat absorption performance is improved and exhaust heat is efficiently recovered.

  Then, from the flange portions 21B and 21B of the pair of high temperature side finned heat flow plates 21 and 21 that have recovered the exhaust heat, to the high temperature side of the two sets of thermoelectric power generation element modules 23 and 23 formed on both sides of the low temperature side heat flow plate 22 When the heat input is started, the two sets of thermoelectric generation element modules 23 and 23 start thermoelectric generation. Thus, when the thermoelectric power generation unit 20 at each stage starts thermoelectric generation, the electric energy is charged into the battery 7 via the DC-DC converter 6 that is on / off controlled by the ECU 5.

  Here, in the low load operation region of the internal combustion engine such as when the vehicle is traveling at a low speed, the exhaust heat amount decreases with the exhaust flow rate, and in the high load operation region of the internal combustion engine such as when the vehicle is traveling uphill, the exhaust heat amount increases with the exhaust flow rate. . That is, the amount of exhaust heat increases or decreases according to the load region of the internal combustion engine corresponding to the traveling state of the vehicle, and the exhaust temperature varies greatly. In this case, in each stage of the thermoelectric generator unit 20 constituting the thermoelectric generator 1, the high-temperature finned heat flow plates 21 and 21 repeat thermal expansion and contraction.

  In this case, the flange portions 21B and 21B of the high-temperature finned heat flow plates 21 and 21 repeat thermal expansion and thermal contraction mainly in the radial direction. At that time, in the two sets of thermoelectric generator modules 23 and 23 constituting each thermoelectric generator unit 20, the high-temperature ends of the p-type thermoelectric generator P and the n-type thermoelectric generator N are respectively connected to the high-temperature side electrodes 23A and 23A. Thus, the low temperature ends also slide relative to the low temperature side electrodes 23B and 23B in the radial direction.

  Accordingly, even if the flange portions 21B and 21B of the high-temperature finned heat flow plates 21 and 21 repeat thermal expansion and contraction in the radial direction, shear stress is generated in the p-type thermoelectric generator P and the n-type thermoelectric generator N. Without deformation, deformation and breakage of the p-type thermoelectric generator P and the n-type thermoelectric generator N are prevented. In particular, the high-temperature ends of the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N are surely in plane contact with the high-temperature side electrodes 23A and 23A, respectively, and the low-temperature ends are reliably flat with the low-temperature side electrodes 23B and 23B, respectively. Because of the contact, the two sets of thermoelectric power generation element modules 23 and 23 sufficiently exhibit their original thermoelectric power generation capability.

  Here, when the high-temperature-side finned heat flow plates 21 and 21 are thermally expanded, the flange portions 21B and 21B tend to have a thickness on the inner peripheral side that is the heat inflow side that is greater than the thickness on the outer peripheral side that is the heat outflow side. Therefore, the inner surfaces of the flange portions 21B and 21B may be slightly inclined.

  In this case, the pair of floor pistons 24A and 24A of each floor piston assembly 24 is tilted in a swinging manner with the spherical member 24C as a fulcrum, so that the p-type thermoelectric power generation of the two sets of thermoelectric power generation element modules 23 and 23 is performed. The element P and the n-type thermoelectric generator N are tilted following the inclination of the inner surface of the flange portions 21B and 21B. The high temperature ends of the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N are surely brought into plane contact with the high temperature side electrodes 23A and 23A, respectively. Accordingly, also in this case, the two sets of thermoelectric power generation element modules 23 and 23 sufficiently exhibit their original thermoelectric power generation capability.

  That is, according to the thermoelectric generator 1 of the present embodiment, the flange portions 21B and 21B of the high-temperature finned heat flow plates 21 and 21 constituting the thermoelectric power generation unit 20 of each stage repeat thermal expansion and contraction in the radial direction. However, since the high temperature side of the thermoelectric generator modules 23 and 23 is surely in plane contact with the inner surfaces of the flange portions 21B and 21B, the thermoelectric generator modules 23 and 23 can sufficiently exhibit their original thermoelectric generation capability. it can.

  Further, even if the flange portions 21B and 21B of the heat flow plates 21 and 21 with the high temperature side fins are thermally expanded and contracted, and the inner side surfaces thereof are inclined, the pair of floor pistons 24A and 24A of the floor piston assembly 24 is true. Since the high temperature side of the thermoelectric generator modules 23 and 23 follows the inclination of the inner side surfaces of the flange portions 21B and 21B by tilting the ball member 24C in a swinging state with the fulcrum as a fulcrum, the thermoelectric generator element The modules 23 and 23 can fully exhibit their original thermoelectric generation capability.

  Further, the high-temperature-side finned heat flow plates 21 and 21 serving as heat recovery members for recovering the exhaust heat have a structure having a plurality of comb-shaped fins 21C that are alternately meshed with a predetermined clearance. The fins 21C and 21C constitute dense fins that are generally difficult to manufacture. And the heat absorption performance of the high-temperature-side finned heat flow plates 21 and 21 can be improved by the dense fins in which the number of fins is substantially doubled.

  In the thermoelectric generator 1 of the present embodiment, even when the internal combustion engine is in a low load operation region and the exhaust heat quantity is reduced, such as when the vehicle is traveling at a low speed, the exhaust gas in the thermoelectric generator 1 is on the exhaust inflow side. Twelve sets of each thermoelectric power generation element module 23 constituting each of the six stages of thermoelectric power generation units 20 arranged reliably generate thermoelectric power.

  Further, the inner space of the cooling water case 10 that is blocked from outside air by the inflow side bellows tube 13 and the outflow side bellows tube 14 is filled with an appropriate inert gas such as nitrogen gas, and the thermoelectric power generation of the thermoelectric power generation unit 20 in each stage. Since the element module 23 is prevented from being oxidized all at once, it is not necessary to take a countermeasure for preventing the oxidation of the thermoelectric power generation element module 23 for each stage of the thermoelectric power generation unit 20, and the manufacturing becomes easier.

  The thermoelectric generator according to the present invention is not limited to the above-described embodiment. For example, the thermoelectric power generation unit 20 has a total of 12 stages in the example shown in FIG. 7, but the number of stages can be increased or decreased as appropriate. Further, in the example shown in FIG. 10, the thermoelectric power generation element module 23 of the thermoelectric power generation unit 20 is electrically divided into two groups of 12 groups in total of 12 groups, but 3 groups of 4 groups each. It is also possible to divide into four groups, or divide into four groups of three groups.

  Further, the pitch partition member 10C of the cooling water case 10 shown in FIG. 8 may have a small pitch interval so as to be in a dense state. In this case, since the heat radiation area of the spiral partition member 10C functioning as a heat radiation fin is increased and the thermal resistance from the cylindrical inner wall member 10A to the cooling water is decreased, the p-type thermoelectric generator P and the n-type thermoelectric generator N The cold end of is effectively cooled. As a result, the temperature difference Δt between the high temperature end and the low temperature end of the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N increases, and the amount of thermoelectric power generated by each thermoelectric power generation element module 23 increases.

  Moreover, the thermoelectric generation unit 20 can be changed into a structure as shown in FIGS. In the thermoelectric power generation unit 20 shown in FIG. 16, a cooling water passage 30 is formed in which the cooling water in the cooling water case 10 passes through the pair of floor pistons 24A and 24A and circulates in the low temperature side heat flow plate 22. As a sealing structure of the cooling water passage 30, an O-ring 31 is mounted on the outer peripheral surface of the fitting portion 22A of the low-temperature heat flow plate 22, and an O-ring 32 is mounted on the outer periphery of the pair of floor pistons 24A and 24A. Has been.

  In the thermoelectric power generation unit 20 shown in FIG. 16, the pair of floor pistons 24A, 24A is cooled by the cooling water circulating in the cooling water passage 30, so that the low temperature of the two sets of thermoelectric power generation element modules 23, 23 on both sides thereof is reduced. The low-temperature ends of the p-type thermoelectric generator P and the n-type thermoelectric generator N that are on the side are cooled. As a result, the temperature difference Δt between the high temperature end and the low temperature end of the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N increases, and the amount of thermoelectric power generated by each thermoelectric power generation element module 23 increases.

  Here, a coil spring 33 is interposed between the opposed surfaces of the pair of floor pistons 24A, 24A shown in FIG. 16 instead of the true spherical member 24C shown in FIG. In this case, by setting the spring force of the coil spring 33 to an appropriate value, the pair of floor pistons 24A, 24A is a p-type thermoelectric power generation that is the high temperature side of the two sets of thermoelectric power generation element modules 23, 23 on both sides thereof. The high temperature ends of the element P and the n-type thermoelectric power generation element N can be pressed to the inner surfaces of the flange portions 21B and 21B of the high temperature side finned heat flow plates 21 and 21 via the high temperature side electrodes 23A and 23A, respectively. it can.

  In the thermoelectric power generation unit 20 shown in FIG. 17, the low temperature side electrodes 23B and 23B of the two sets of thermoelectric power generation element modules 23 and 23 are previously soldered to the low temperature ends of the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N, respectively. It is joined by. Further, the heat flow plates 21 and 21 with high-temperature fins are made of an insulating material such as ceramics so that the inner surfaces of the flange portions 21B and 21B are formed into flat surfaces without the recesses 21D and 21D, and the flat inner surfaces are insulated. The high temperature side electrodes 23A and 23A without the layer Z1 are directly joined.

  In the thermoelectric generation element modules 23 and 23 shown in FIG. 17, the high-temperature ends of the p-type thermoelectric generation element P and the n-type thermoelectric generation element N are in slidable plane contact with the high-temperature side electrodes 23A and 23A, respectively. Therefore, even if the flange portions 21B and 21B of the high-temperature finned heat flow plates 21 and 21 are thermally expanded and contracted in the radial direction, no shear stress is generated in the p-type thermoelectric generator P and the n-type thermoelectric generator N. . Since the low temperature side heat flow plate 22 and the low temperature side electrodes 23B and 23B have small temperature fluctuations and almost no radial thermal expansion and contraction, the p-type thermoelectric generator P and the n-type thermoelectric generator N have shear stress. Is not generated, and the p-type thermoelectric generator P and the n-type thermoelectric generator N are prevented from being damaged.

  The thermoelectric power generation unit 20 shown in FIG. 18 is obtained by changing the true spherical member 24C between the pair of floor pistons 24A and 24A shown in FIG. 17 into a coil spring 33 shown in FIG. The same configuration as the thermoelectric power generation unit 20 shown in FIG. For this reason, also in the thermoelectric power generation unit 20 shown in FIG. 18, no shear stress is generated in the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N, and the breakage is prevented.

  In the thermoelectric power generation unit 20 shown in FIGS. 17 and 18, the high temperature side electrodes 23A and 23A are in plane contact without being joined to the flat inner side surfaces of the flange portions 21B and 21B of the high temperature side finned heat flow plates 21 and 21. In this way, the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N may be diffusion bonded to the high temperature ends.

  FIG. 19 shows the one-side thermoelectric power generation element module 23 configured as described above. The p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N are joined at the low temperature end by a low temperature side electrode 23B by soldering or the like. The high temperature side electrode 23A is diffusion bonded to the high temperature end. In this case, since the high temperature side electrode 23A is slidably brought into flat contact with the flat inner surface of the flange portion 21B of the high temperature side finned heat flow plate 21 shown in FIGS. 17 and 18, FIG. 17 and FIG. Like the thermoelectric power generation unit 20 shown, the p-type thermoelectric power generation element P and the n-type thermoelectric power generation element N are prevented from being damaged.

  Note that the low temperature side electrode 23B shown in FIG. 19 may be configured to be in plane contact without being joined to the low temperature ends of the p-type thermoelectric generator P and the n-type thermoelectric generator N. FIG. 20 shows the one-side thermoelectric power generation element module 23 configured as described above. In this case as well, the p-type thermoelectric power generation element P and the n-type thermoelectric power generation are the same as the thermoelectric power generation unit 20 shown in FIGS. Damage to the power generating element N is prevented.

1 is a plan view showing a schematic structure of an exhaust system of an internal combustion engine in which a thermoelectric generator according to an embodiment of the present invention is interposed. It is a perspective view which shows the external appearance of the thermoelectric power generator shown in FIG. FIG. 3 is a side view of the thermoelectric generator shown in FIG. 2. It is a front view of the thermoelectric generator shown in FIG. It is a cross-sectional perspective view which shows the internal structure of the thermoelectric power generator shown in FIG. FIG. 6 is an exploded perspective view of the thermoelectric generator shown in FIG. 5. It is a longitudinal cross-sectional view which shows the internal structure of the thermoelectric power generator shown in FIG. It is a cross-sectional perspective view which shows the internal structure of the cooling water case shown in FIG. It is a disassembled perspective view which shows the structure of the thermoelectric power generation unit shown in FIG. It is a perspective view which shows the combined state of the thermoelectric power generation element module decomposed | disassembled and shown in FIG. FIG. 11 is a partially enlarged cross-sectional view illustrating the output terminal fixing structure illustrated in FIG. 10 by enlarging the vicinity of the inflow side bellows pipe illustrated in FIG. 7. It is a disassembled perspective view which cuts out and shows a part of thermoelectric power generation unit shown in FIG. FIG. 10 is an exploded perspective view of the floor piston assembly shown in FIG. 9. It is sectional drawing of the high temperature side electrode and low temperature side electrode shown with the p-type thermoelectric power generation element (n-type thermoelectric power generation element) of the thermoelectric power generation element module shown in FIG. It is the elements on larger scale which expand and show a part of thermoelectric power generation unit shown in FIG. It is a partial expanded sectional view of the thermoelectric power generation unit which shows the modification of the low temperature side heat flow board shown in FIG. FIG. 16 is a partial enlarged cross-sectional view of a thermoelectric power generation unit showing a modification of the thermoelectric power generation element module shown in FIG. 15. FIG. 18 is a partial enlarged cross-sectional view of a thermoelectric power generation unit showing a modification of the floor piston assembly shown in FIG. 17. It is a perspective view of the thermoelectric power generation element module shown in FIG. 17 and FIG. It is a disassembled perspective view which shows the modification of the thermoelectric power generation element module shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Thermoelectric generator, 5 ... ECU, 6 ... DC-DC converter, 7 ... Battery, 8 ... Bypass pipe, 9 ... Bypass valve, 10 ... Cooling water case, 10A ... Cylindrical inner wall member, 10B ... Cylindrical outer wall member DESCRIPTION OF SYMBOLS 10C ... Spiral partition member, 10D ... Inflow side nipple, 10E ... Outflow side nipple, 11 ... Inflow side housing, 12 ... Outflow side housing, 13 ... Inflow side bellows pipe, 14 ... Outflow side bellows pipe, 15 ... Cooling water circulation Pump, 16 ... Radiator, 17 ... Belleville spring, 18 ... Push nut, 20 ... Thermoelectric power generation unit, 21 ... Heat flow plate (heat recovery member) with high temperature side fin, 21A ... Main body, 21B ... Flange, 21C ... Fin, 22 ... low temperature side heat flow plate (heat radiating member), 22A ... fitting part, 22B ... mounting part, 22C ... concave part, 22D ... piston accommodation hole, 23 ... thermoelectric power generation element module, 23A ... High temperature side electrode, 23B ... Low temperature side electrode, 23C ... Holder, 24 ... Floor piston assembly, 24A ... Floor piston, 24C ... Spherical member, 24D ... Low elastic layer, 24E ... Piston body, 25, 26 ... Output Terminal, 27 ... Copper plate wiring, 28 ... Nut, 29A, 29B ... Insulating collar, 30 ... Cooling water passage, 33 ... Coil spring, G1, G2 ... Gasket, N ... N-type thermoelectric generator, P ... P-type thermoelectric generator M1, M2 ... hard plating layer, Z1, Z2 ... insulating layer.

Claims (3)

A thermoelectric power generation device comprising a thermoelectric power generation element module in which a plurality of thermoelectric power generation elements capable of thermoelectric power generation are brought into contact with a heat recovery member at a high temperature end side and a low temperature end side in contact with a heat dissipation member,
The heat recovery member is formed in an annular shape having a flange portion, and is provided on the outer periphery of a pipe through which exhaust flows.
The thermoelectric power generation element module, thermoelectric generator that hot side to the flange portion of the front Stories heat recovery member is characterized in that it is pressed are configured in a ring shape to be a plane contact.   The heat recovery member has a large number of comb-shaped fins arranged radially, and the fins of a pair of adjacent heat recovery members are configured to mesh with each other with a predetermined clearance therebetween. The thermoelectric generator according to claim 1. The pair of pressing members which can be tilted with respect to each other via a ball member as means for pressing the high temperature side of the thermoelectric power generation element module against the flange portion of the heat recovery member. 2. The thermoelectric generator according to 2.

Images