JP2014086454A - Thermoelectric generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoelectric generator of simple structure having high power generation efficiency which is capable of ensuring a stable contact state between a heat exchanger surface of a thermoelectric element and heat exchanger plates on the high temperature side and the low temperature side.SOLUTION: A thermoelectric generator comprises a heat exchanger plate 32a on the high-temperature side and a heat exchanger plate 45a on the low-temperature side and a plurality of thermoelectric elements 43 respectively having a heat exchanger surface 43a on the heat absorbing side which contacts the heat exchanger plate 32a on the high-temperature side and a heat exchanger surface 43b on the heat dissipation side which contacts the heat exchanger plate 45a on the low-temperature side, and generates electric power by the thermoelectric elements 43 depending on the temperature difference between the heat absorbing surface and the heat dissipation surface. At least one heat exchanger plate of the heat exchanger plate 32a on the high-temperature side and the heat exchanger plate 45a on the low-temperature side includes a contact region R1 contacting the thermoelectric element 43 and a non-contact region R2 not contacting the thermoelectric element. The rigidity of a wall surface part 45a1 of the contact region R1 is lower than that of a wall surface part 45a2 of the non-contact region R2.

Description

  The present invention relates to a thermoelectric power generation device, and more particularly to a thermoelectric power generation device in which a plurality of thermoelectric elements electrically connected in series are thermally arranged in parallel between a high temperature side heat transfer plate and a low temperature side heat transfer plate. .

  Conventionally, as a thermoelectric generator that generates electricity according to the temperature difference between the two sides of the thermoelectric element, for example, the installation space of the thermoelectric element is evacuated and sealed with a vacuum laminator etc. A device for avoiding breakage is known (see, for example, paragraphs 0052 and 0057 of Patent Document 1).

  In addition, by holding a plurality of thermoelectric elements by a holding mechanism using a band, it is possible to appropriately hold a plurality of thermoelectric elements while absorbing thermal strain between a high temperature side and a low temperature side where a difference in thermal expansion occurs. Is also known (see, for example, Patent Document 2).

  Furthermore, a soft metal layer is interposed between the insulating layers on both ends of the thermoelectric conversion module and the heat transfer plates on the high temperature side and the low temperature side to absorb the unevenness of the contact surfaces between them, and the heat transfer efficiency is increased by increasing the contact area. There is one that improves the power generation output by improving the power (see, for example, Patent Document 3).

JP 2007-273572 A JP 2006-109539 A JP 2000-232244 A

  However, in the conventional thermoelectric power generation device as described above, it becomes easy to invite complication of the device configuration in order to ensure a stable contact state of the heat transfer surfaces of the plurality of thermoelectric elements, and when the device configuration is simplified, There has been a problem that thermoelectric power generation efficiency tends to decrease due to a decrease in contact area due to thermal strain or the like.

  Accordingly, the present invention has an object to provide a simple high power generation efficiency thermoelectric generator having a configuration capable of ensuring a stable contact state between the heat transfer surface of the thermoelectric element and the heat transfer plates on the high temperature side and the low temperature side. And

  In order to achieve the above object, the thermoelectric power generator according to the present invention includes (1) a high-temperature side heat transfer plate and a low-temperature side heat transfer plate, and a heat-absorbing surface and the low-temperature side that are in contact with the high-temperature side heat transfer plate. A plurality of thermoelectric elements having a heat radiating surface in contact with the heat transfer plate, wherein the thermoelectric power generator generates electric power according to a temperature difference between the heat absorbing surface and the heat radiating surface by the thermoelectric element, wherein the high temperature At least one of the heat transfer plate on the side and the heat transfer plate on the low temperature side has a contact region in contact with the thermoelectric element and a non-contact region not in contact with the thermoelectric element, and the wall surface of the contact region The portion has a lower rigidity than the wall surface portion of the non-contact region.

  In this thermoelectric generator, the wall surface portion of the contact region in at least one heat transfer plate that contacts the thermoelectric element is less rigid than the wall surface portion of the non-contact region in the heat transfer plate. At least one of the heat absorbing surface and the heat radiating surface of the plurality of thermoelectric elements has a low support rigidity on the wall surface portion of the contact region that is partially low in the heat transfer plate having the required support rigidity. It can be supported. Therefore, thermal distortion and contact surface irregularities are easily absorbed between the heat transfer surfaces of the plurality of thermoelectric elements and the high temperature side and low temperature side heat transfer plates. A thermoelectric generator with a simple and high power generation efficiency having a configuration capable of ensuring a stable contact state with the heat transfer plate. Since at least one of the heat transfer plates is used, only the wall surface portion of the contact area of the heat transfer plate on either the high temperature side or the low temperature side can be made to have low rigidity. In that case, the wall surface portion of the contact region of one heat transfer plate may have a lower rigidity than the wall surface portion of the contact region of the other heat transfer plate.

  In the thermoelectric generator of the present invention, preferably, (2) a closed installation space for installing the thermoelectric element is formed between the high temperature side heat transfer plate and the low temperature side heat transfer plate, The internal pressure is maintained at a pressure lower than atmospheric pressure.

  With this configuration, the contact state between the heat transfer surface of the thermoelectric element and the heat transfer plate on the high temperature side and the low temperature side is more stable, and heat transfer by air in the installation space is suppressed, and the high temperature side around the thermoelectric element In the state in which an effective heat insulating layer is formed between the heat transfer plate and the low-temperature heat transfer plate, heat absorption and heat dissipation by the thermoelectric element are effectively performed. Therefore, it becomes a thermoelectric power generator with high power generation efficiency.

  The installation space for installing the plurality of thermoelectric elements is formed by at least one heat transfer plate. When the installation space is formed inside one heat transfer plate, one heat transfer plate is It will be a case that can be closed.

  In the thermoelectric generator having the configuration of (2) above, (3) the one heat transfer plate absorbs heat from the thermoelectric element via the high temperature side heat transfer plate and the low temperature side It may be configured by a pipe wall of a pipe through which any one of the low-temperature-side heat medium that radiates heat from the thermoelectric element through the heat transfer plate.

  In this case, the pipe wall of the pipe through which one heat medium passes has a non-contact area and a contact area, and a low support rigidity while a plurality of thermoelectric elements are in contact with the heat transfer surface on the wall surface portion of the contact area. Supported by Therefore, a plurality of thermoelectric elements can be directly supported by a pipe having low rigidity only at a part of the wall surface portion of the contact region, and a thermoelectric generator having a very simple configuration can be obtained.

  In the thermoelectric generator having the configuration of (1) or (2), (4) the one heat transfer plate absorbs heat by the high temperature heat transfer plate and the low temperature side heat medium. The pipe wall of the pipe through which any one of the low-temperature side heat medium that releases heat from the heat transfer plate, and the thermoelectric element in contact with the pipe wall of the pipe on one side and on the other side And a thermally conductive and electrically insulating substrate in contact with the substrate.

  In this case, one heat transfer plate constituted by the pipe wall of the pipe through which one heat medium passes and the heat conductive electrically insulating substrate in contact with the pipe wall has a non-contact area and a contact area, and the contact area A plurality of thermoelectric elements are supported with low support rigidity while contacting the heat transfer surface with respect to the thermally conductive electrically insulating substrate constituting the wall surface portion of the substrate. Therefore, the heat transfer surfaces of the plurality of thermoelectric elements can be stably brought into contact with the wall surface portion of the contact region of one heat transfer plate that includes a part of the heat conductive electrically insulating substrate and becomes the low rigidity portion.

  In the thermoelectric generator having the configuration of (4) above, (5) the plurality of thermoelectric elements are arranged on the other surface side of the thermally conductive electrically insulating substrate with a space therebetween, and the heat conduction The electrically insulating substrate may have a through hole penetrating in the thickness direction in a non-contact portion with the plurality of thermoelectric elements.

  In this case, when the heat conductive electrically insulating substrate and the tube wall on the one surface side thereof are in close contact with each other, the air between them can be easily discharged through the through-hole, and the remaining air allows the heat conductive electrically insulating substrate and the tube wall to be discharged. It can suppress that adhesiveness falls.

  According to the present invention, the wall surface portion of the contact region of one heat transfer plate that contacts the thermoelectric element is made to be less rigid than the wall surface portion of the non-contact region, and the heat transfer surfaces of the plurality of thermoelectric elements are transferred to the high temperature side and the low temperature side. Because it is easy to absorb thermal distortion and contact surface unevenness between the heat plate and the heat transfer surface of the thermoelectric element, the configuration that can ensure a stable contact state between the high temperature side and low temperature side heat transfer plate It is possible to provide a simple thermoelectric generator with high power generation efficiency.

1 is a schematic configuration diagram of an exhaust heat recovery system for an internal combustion engine including a thermoelectric power generator according to a first embodiment of the present invention. It is principal part sectional drawing of the thermoelectric generator which concerns on 1st Embodiment of this invention. It is a principal part schematic block diagram of the exhaust heat recovery system which shows the aspect which has arrange | positioned the thermoelectric power generating apparatus which concerns on 1st Embodiment of this invention on the bypass channel which bypasses the valve | bulb on an exhaust channel. It is principal part sectional drawing of the thermoelectric power generating apparatus which concerns on 2nd Embodiment of this invention. It is arrangement | positioning explanatory drawing of the several thermoelectric element and electrode which electrically connects these elements in series in the thermoelectric power generation apparatus which concerns on 2nd Embodiment of this invention. It is principal part sectional drawing of the thermoelectric power generating apparatus which concerns on 3rd Embodiment of this invention. It is principal part sectional drawing of the thermoelectric power generating apparatus which concerns on 4th Embodiment of this invention. It is principal part sectional drawing of the thermoelectric power generating apparatus which concerns on 5th Embodiment of this invention.

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

(First embodiment)
1 to 3 show a thermoelectric generator according to a first embodiment of the present invention and an exhaust heat recovery system for an internal combustion engine equipped with the device.

  The exhaust heat recovery system of the present embodiment is installed in a water-cooled multi-cylinder internal combustion engine, for example, a 4-cycle gasoline engine, which is mounted on an automobile (vehicle). Of course, the thermoelectric generator according to the present invention and the exhaust heat recovery system including the thermoelectric generator may be mounted on another engine having different fuel. In addition, it goes without saying that the thermoelectric generator of the present invention can be used other than the exhaust heat recovery system of an internal combustion engine, as long as it can absorb heat from the high temperature side heat source and release heat to the low temperature side heat source by the thermoelectric element. The heat source is not limited. However, the present invention is suitable for a thermoelectric power generation apparatus that generates power while performing heat exchange between two heat media using a plurality of thermoelectric elements (thermoelectric conversion elements).

  First, the configuration of the present embodiment will be described.

  As shown in FIG. 1, the engine 1 houses a reciprocable piston 2 in each cylinder 11 c of a main body block 11 to form a combustion chamber 3, and the piston 2 is connected via a connecting rod 4. It is connected to the crankshaft 5. In the upper part of the combustion chamber 3, there are an intake valve 6 and an exhaust valve 7 that are opened and closed according to the rotation of the crankshaft 5 by a valve mechanism (not shown), and an ignition plug 8 that is exposed in the combustion chamber 3 so as to be capable of spark ignition. Is provided. The intake valve 6 communicates the combustion chamber 3 with the intake passage 21 including the internal passage of the intake pipe 21P when the valve is opened, and the exhaust valve 7 exhausts the combustion chamber 3 including the internal passage of the exhaust pipe 31P when the valve is opened. It communicates with the passage 31. When the piston 2 descends in a state where the combustion chamber 3 communicates with the intake passage 21 by opening the intake valve 6, the combustion chamber 3 can suck air through the intake passage 21. Further, when the piston 2 rises with the combustion chamber 3 communicating with the exhaust passage 31 by opening the exhaust valve 7, the combustion chamber 3 can exhaust the exhaust gas through the exhaust passage 31.

  The intake passage 21 can introduce air through an air cleaner (not shown), and the intake air amount can be adjusted according to the opening of the throttle valve 22, and the intake air amount is detected by the air flow meter 23. ing. Further, a surge tank 24 for reducing pressure pulsation in the intake passage 21 is provided on the downstream side of the throttle valve 22, and an intake port portion 21 c branched to each cylinder 11 c on the downstream side of the surge tank 24 is provided in the intake port portion 21 c. An injector 25 for injecting fuel into the intake passage 21 and mixing the fuel into the intake air is provided. The ignition plug 8, the throttle valve 22 and the injector 25 are controlled so that their ignition timing, throttle opening and injection amount (injection time) are controlled by an on-vehicle electronic control unit (hereinafter referred to as ECU) 50, respectively. It has become. Each injector 25 corresponding to each cylinder 11c is connected to a delivery pipe 26 that accumulates and stores fuel from a fuel pump (not shown), and injects fuel of a predetermined fuel pressure distributed from the delivery pipe 26 into the combustion chamber 3. The valve is opened so that the injection amount can be controlled by duty control of the valve opening time.

  On the other hand, a water jacket 11w through which cooling water passes is formed inside the cylinder block and cylinder head forming each cylinder 11c of the engine 1. Although not shown in detail, the cooling water that has passed through the water jacket 11w flows out from the cooling water outlet formed in the cylinder head of the engine 1, and the cooling water that has flowed out of the engine 1 is externally supplied by the radiator 12. It is cooled by heat exchange with the air. Further, a water pump 15 is disposed upstream of the water jacket 11w of the engine 1, and a thermostat 14 that opens and closes in response to the temperature of the cooling water is disposed on the suction side of the water pump 15. Yes.

  The cooling water that has flowed out of the engine 1 is also supplied to a heater core (not shown) that performs heat exchange between the cooling water and air for heating the passenger compartment. The engine coolant that has passed through the heater core and the like is supplied to the EGR cooler 18 and the exhaust heat recirculation and thermoelectric generator 40 through the branch passages 19a and 19b of the coolant passage 19, respectively. Yes. The cooling water flowing out from the engine 1 is also passed through a throttle body (not shown) that forms part of the intake passage and forms part of the throttle valve.

  The exhaust heat recirculation and thermoelectric generator 40 (hereinafter simply referred to as the thermoelectric generator 40) recovers exhaust heat by exchanging heat between the exhaust gas passing through the exhaust pipe of the engine 1 and the engine coolant. The heater core and the warm-up performance of the engine 1 can be improved.

  The thermoelectric generator 40 is provided with a thermostat type exhaust gas control actuator 41 connected to the cooling water passage 19. The exhaust gas control actuator 41 is a valve that can throttle a part of the exhaust passage 31. It has a body 41a.

  More specifically, as shown in FIG. 3, the valve body 41a of the thermoelectric generator 40 is attached to the main passage portion 31a of the exhaust passage 31, and the main body 40M of the thermoelectric generator 40 bypasses the valve body 41a. The exhaust passage 31 is mounted on a bypass passage portion 31b connected in parallel to the main passage portion 31a. When the main passage portion 31a of the exhaust passage 31 is throttled by the valve body 41a, the flow rate of the exhaust gas passing through the inside of the bypass passage portion 31b to which the main body portion 40M of the thermoelectric generator 40 is mounted increases. ing.

  As shown in FIG. 2, the bypass passage portion 31b of the exhaust passage 31 is formed by a bypass pipe 32 connected to the exhaust pipe 31P, and a plurality of bypass pipes 32 are provided on the inner peripheral surface 32i side of the bypass pipe 32. A heat absorbing member 33 having a heat absorbing fin portion 33f and a pair of heat collecting wall portions 33s is provided. The plurality of heat-absorbing fin portions 33f make the heat transfer surface from the exhaust gas passing through the bypass pipe 32 larger so as to absorb heat easily. The heat collecting wall portion 33s is formed integrally with the plurality of heat absorbing fin portions 33f, and has a high thermal conductivity that moves the heat absorbed by the plurality of heat absorbing fin portions 33f to the inner peripheral surface 32i side of the bypass pipe 32. It is.

  On the other hand, on the outer peripheral side of the bypass pipe 32, a plurality of thermoelectric elements 43 including a plurality of pairs of P-type semiconductor elements and N-type semiconductor elements (Peltier elements) and forming at least one, for example, a plurality of thermoelectric power generation modules. And the cylindrical cooling water piping 45 is provided so that the flat intermediate part of these thermoelectric elements 43 and bypass piping 32 may be surrounded.

  The bypass pipe 32, the plurality of thermoelectric elements 43, and the cooling water pipe 45 constitute the main part of the thermoelectric generator 40, and the exhaust gas control actuator 41 increases the flow rate of the exhaust gas passing through the bypass pipe 32. When this is done, power is generated by a plurality of thermoelectric elements 43.

  Specifically, the bypass pipe 32 has a flat tube shape at least in an intermediate portion of the passage extending direction, and the flat tube wall portions 32a and 32b on one surface side and the other surface side thereof, and these flat tube wall portions. 32a and 32b are connected to each other to form part of the bypass passage portion 31b.

  The flat tube wall portions 32 a and 32 b of the bypass pipe 32 are in wide contact with the pair of heat collecting wall portions 33 s of the heat absorbing member 33 on the inner peripheral surface 32 i side of the bypass pipe 32. Further, the flat tube wall portions 32 a and 32 b on the one surface side and the other surface side are in contact with the plurality of thermoelectric elements 43 on the outer peripheral surface side of the bypass pipe 32.

  The flat pipe wall portions 32a and 32b on the one surface side and the other surface side of the bypass pipe 32 can be absorbed by the plurality of thermoelectric elements 43 when heated to a high temperature by the heat absorbing member 33 that absorbs heat from the high-temperature exhaust gas. It is a heat transfer plate on the side.

  The plurality of thermoelectric elements 43 are thermally arranged in parallel between the cylindrical cooling water pipe 45 and the bypass pipe 32 and are electrically connected in series.

  In addition, each thermoelectric element 43 has a flat high-temperature end surface 43a (heat absorption surface) contacting the flat pipe wall portions 32a and 32b on one surface side and the other surface side of the bypass pipe 32, and an end surface portion 43a on the high-temperature side. It has an end surface portion 43b (heat dissipating surface) on the low temperature side parallel to the surface.

  The plurality of thermoelectric elements 43 have a Seebeck effect (transfer of electrons to the low temperature side in the N-type semiconductor element and P-type in accordance with the temperature difference between the end faces 43a and 43b on the high temperature side and the low temperature side of each Peltier element. Electricity can be generated by generating holes in the semiconductor element to the low temperature side). In addition, the plurality of thermoelectric elements 43 are configured to be able to generate power with at least one set of thermoelectric elements 43 when a plurality of thermoelectric elements 43 connected in series are used as one set of thermoelectric elements 43. That is, the thermoelectric power generation device 40 has a function of generating electric power by a plurality of thermoelectric elements 43 according to the temperature difference between the both end surface portions 43a and 43b.

  The cooling water pipe 45 accommodates the inner tube wall 45a (one heat transfer plate) contacting the flat end surface portion 43b on the low temperature side of the plurality of thermoelectric elements 43 and the inner tube wall 45a in a fixed position inside. A cylindrical outer tube wall 45b that forms a cooling water passage 45c between the inner tube wall 45a while being held, and both end sides of the inner tube wall 45a and the outer tube wall 45b in the axial direction of the bypass pipe 32 And both end side wall portions 45d for closing the cooling water passage 45c.

  The inner pipe wall 45a of the cooling water pipe 45 is a low-temperature heat transfer plate that can dissipate heat from the plurality of thermoelectric elements 43 when cooled by engine cooling water passing through the cooling water passage 45c. .

  In addition, the inner pipe wall 45a of the cooling water pipe 45 has a heat transfer surface group of a plurality of thermoelectric elements 43 electrically connected in series, for example, a plurality of end face parts 43b arranged at equal intervals on the same plane. It has a contact region R1 in contact with the island-shaped gathering and a non-contact region R2 in contact with the heat transfer surface group of the plurality of thermoelectric elements 43. The wall surface portion 45a1 of the contact region R1 on both the upper and lower sides in FIG. 2 on the inner peripheral surface 45i (one surface) side of the inner tube wall portion 45a is thinner than the wall surface portion 45a2 of the non-contact region R2 in the inner tube wall portion 45a (see FIG. The wall portion 45a2 of the non-contact region R2 is formed with a relatively small thickness, and is relatively rigid (in this case, rigid to withstand the force applied and suppress deformation, for example, bending rigidity. Is low). For example, the wall thickness 45a1 of the contact region R1 of the inner tube wall 45a is easily elastically deformed according to the pressure of the cooling water passing through the cooling water passage 45c and the pressure in the installation space 46. The thinning is such that the adhesion between the end surface portion 43b of each thermoelectric element 43 and the wall surface portion 45a1 of the contact region R1 is enhanced.

  The inner pipe wall portion 45 a of the cooling water pipe 45 includes an exhaust gas (high temperature side heat medium) that absorbs heat from the plurality of thermoelectric elements 43 via the flat pipe wall parts 32 a and 32 b of the bypass pipe 32 and the cooling water pipe 45. It becomes the pipe wall of the piping through which any one heat medium, for example, engine cooling water, is radiated from the plurality of thermoelectric elements 43 through the inner pipe wall portion 45a. Yes.

  When the plurality of thermoelectric elements 43 are configured as a plurality of thermoelectric power generation modules 43M (see FIG. 2) each integrating a plurality of elements, the area of each wall surface portion 45a1 configures one thermoelectric power generation module. It is the same area as or larger than the area of the end face of each thermoelectric power generation chip, for example, slightly larger than the area of the end face of each thermoelectric power generation module. Further, the shape of the cooling water passage 45c of the cooling water pipe 45 is not limited. For example, as shown in FIG. 1, the cooling water inlet position of the cooling water passage 45c is the cooling water passage 45c. It is set so as to be located downstream of the water discharge port position in the exhaust direction.

  Between the bypass pipe 32 and the inner pipe wall 45a, at least between the flat pipe walls 32a and 32b on one side and the other side of the bypass pipe 32 and the inner pipe wall 45a of the cooling water pipe 45, a plurality of A closed installation space 46 in which the thermoelectric element 43 is installed is formed. The pressure inside the installation space 46 is maintained at a pressure lower than atmospheric pressure.

  Specifically, the cooling water pipe 45 surrounds the periphery of the bypass pipe 32, and the inner pipe wall part 45a and the outer pipe wall part 45b are connected to each other so as to define an installation space 46 therebetween. Yes.

  The installation space 46 can communicate with the inside of the surge tank 24 through a pressure reducing pipe 48 equipped with a known one-way valve (check valve) 47, and the pressure in the surge tank 24 is higher than the pressure in the installation space 46. When the pressure becomes low, the one-way valve 47 is opened and the inside of the installation space 46 is the intake negative pressure in the surge tank 24 (for example, the combustion chamber 3 with the throttle valve 22 opened to a low opening). The pressure is reduced by the pressure in the intake pipe when air is sucked into the inside. That is, the surge tank 24, the one-way valve 47, and the pressure reducing pipe 48 introduce the intake negative pressure (negative pressure in the intake pipe) of the engine 1 into the installation space 46 to reduce the pressure inside the installation space 46. 49. The pressure reducing mechanism 49 is a pressure reducing state holding mechanism capable of holding the pressure inside the installation space 46 in a predetermined pressure reducing state in cooperation with the pressure reducing pipe 48 when the one-way valve 47 is closed.

  More specifically, the one-way valve 47 is a pressure inside the installation space 46 in a state in which intake negative pressure is generated in the surge tank 24 and the differential pressure across the one-way valve 47 reaches a predetermined value. Is opened so as to allow the pressure to be reduced by the pressure reducing mechanism 49, and under the condition that the intake negative pressure is reduced in the surge tank 24 and the differential pressure before and after it falls below a predetermined value, The valve closed state can be maintained so as to maintain the pressure.

  In addition, the installation space 46 here is configured so that both end portions of the inner pipe wall portion 45a and the bypass pipes in the vicinity thereof are arranged so that both end portions of the inner pipe wall portion 45a in the axial direction of the bypass pipe 32 approach the bypass pipe 32 side. At least one of the pipe diameters of 32 is changed to form a cylindrical closed space in which a plurality of thermoelectric elements 43 can be installed by the bypass pipe 32 and both ends of the inner pipe wall 45a.

  Of course, the installation space 46 may take any cross-sectional shape according to the arrangement pattern of the plurality of thermoelectric elements 43, the shapes of the exhaust pipe 31P and the cooling water pipe 45, and the like, and the circumference of the exhaust pipe 31P or the bypass pipe 32 thereof. A plurality of parallel installation spaces (such as a shape obtained by dividing the cylindrical space into a plurality of substantially strip-shaped spaces) adjacent to each other in the direction may be provided, or a plurality of adjacent installation spaces adjacent to each other in the axial direction of the exhaust pipe 31P or the bypass pipe 32 thereof. It may be a cylindrical space. Moreover, you may provide one partition plate and a radiation fin in the inside of the cooling water channel | path 45c.

  The installation space 46 is formed by at least one of the heat transfer plates on the high temperature side and the low temperature side, and when the installation space 46 is formed inside one of the heat transfer plates, One of the heat transfer plates is a case that can be closed.

  Next, the operation will be described.

  In the exhaust heat recovery system provided with the thermoelectric power generator of the present embodiment configured as described above, the temperature of the cooling water passing through the cooling water passage 19 is lower than the threshold temperature, and heat recovery to the cooling water should be given priority. When the condition is satisfied, the ECU 50 operates the exhaust gas control actuator 41 to displace the valve body 41a toward the valve closing position so as to close the main passage portion 31a of the exhaust passage 31.

  At this time, high-temperature exhaust gas enters the bypass passage portion 31 b of the exhaust passage 31, and heat transfer from the exhaust gas to the heat absorption member 33 in the bypass pipe 32 causes the heat of the exhaust gas to pass through the heat absorption member 33. Heat is absorbed by the end surface portion 43a on the high temperature side of the thermoelectric element 43, and the temperature of the end surface portion 43a rises. Further, the engine cooling water flows through the cooling water passage 45c of the cooling water pipe 45, whereby the cooling water in the cooling water pipe 45 is transferred from the low temperature side end face part 43b of the plurality of thermoelectric elements 43 through the inner pipe wall part 45a. The heat is dissipated, and the temperature of the end surface portion 43b on the low temperature side of the plurality of thermoelectric elements 43 decreases.

  Therefore, movement of electrons in the N-type semiconductor element constituting each thermoelectric element 43 to the low temperature side and movement of holes in the P-type semiconductor element to the low temperature side occur, and exhaust through the exhaust passage 31 occurs. Part of the heat of the gas is transferred to the cooling water pipe 45 side through the plurality of thermoelectric elements 43 and is recovered in the cooling water. As a result, the temperature of the cooling water of the engine 1 rises, for example, warming up of the engine 1 at the time of cold start is promoted, and power generation output by the plurality of thermoelectric elements 43 is obtained.

  On the other hand, when the temperature of the cooling water passing through the cooling water passage 45c exceeds the threshold temperature, the ECU 50 operates the exhaust gas control actuator 41 to open the valve body 41a so as to open the main passage portion 31a of the exhaust passage 31. Return to the side. At this time, since the exhaust gas in the exhaust passage 31 can pass downstream without resistance through the main passage portion 31a, the output priority operation of the engine 1 can be performed.

  By the way, in the thermoelectric generator of this embodiment, in the inner pipe wall part 45a of the cooling water piping 45 which contacts the several thermoelectric element 43, the wall surface part 45a1 of contact region R1 is thinner than the wall surface part 45a2 of non-contact area | region R2. It has a low rigidity.

  Accordingly, the plurality of thermoelectric elements 43 are transferred to the wall surface portion 45a1 of the contact region R1 which is in the inner tube wall portion 45a of the cooling water pipe 45 having the required large support rigidity in the non-contact region R2 and partially has low rigidity. The end surface portion 43b on the heat radiating surface side that is the heat surface is supported with low support rigidity.

  And between the end surface part 43b of the some thermoelectric element 43 and the inner pipe wall part 45a of the cooling water piping 45, Furthermore, the other end surface part 43a of the some thermoelectric element 43, the one surface side and other surface of the bypass piping 32 Thermal distortion and contact surface irregularities are easily absorbed between the flat tube wall portions 32a and 32b on the side. As a result, it is possible to ensure a stable close contact state without air accumulation between the end face portions 43a and 43b of the thermoelectric element 43 and the high-temperature side bypass pipe 32 and the low-temperature side cooling water pipe 45. It becomes a simple high power generation efficiency thermoelectric generator having a stable surface contact state.

  In the present embodiment, the thermoelectric power is provided between the flat tube wall portions 32a and 32b of the bypass pipe 32, which is a high temperature side heat transfer plate, and the inner tube wall portion 45a of the cooling water pipe 45, which is a low temperature side heat transfer plate. A closed installation space 46 for installing the element 43 is formed, and the pressure inside the installation space is maintained at a pressure lower than the atmospheric pressure.

  Therefore, in addition to the contact state between the end face portions 43a and 43b of the thermoelectric element 43 and the high temperature side bypass pipe 32 and the low temperature side cooling water pipe 45 being stabilized by the negative pressure in the installation space 46, The heat transfer by air is suppressed, and an effective heat insulating layer is formed around the thermoelectric element 43 between the bypass pipe 32 and the inner pipe wall 45a of the cooling water pipe 45. As a result, the heat absorption from the bypass pipe 32 and the heat dissipation to the cooling water pipe 45 by the plurality of thermoelectric elements 43 are effectively performed, and the exhaust heat recirculation and the thermoelectric generator 40 have high power generation efficiency.

  In addition, since the heat transfer plate that is partially low in rigidity is constituted by the inner pipe wall portion 45a of the cooling water pipe 45 through which the engine cooling water that is the low-temperature side heat medium passes, the cooling through which the engine cooling water passes The inner pipe wall portion 45a of the water pipe 45 is connected to the wall surface portion 45a1 of the low-rigidity contact region R1 out of the high-rigidity non-contact region R2 and the low-rigidity contact region R1. The portion 43b can be supported with low support rigidity while being in contact with the portion 43b.

  As a result, in the present embodiment, the plurality of thermoelectric elements 43 can be directly supported on the inner pipe wall portion 45a of the cooling water pipe 45 having low rigidity only at a part of the wall portion 45a1 of the contact region R1. It becomes a thermoelectric power generator with a very simple configuration.

(Second Embodiment)
4 and 5 show the main part of a thermoelectric generator according to the second embodiment of the present invention.

  Although the present embodiment is different from the first embodiment in the configuration of a part of the thermoelectric generator, the peripheral configuration such as the piping configuration of the internal combustion engine is similar to the first embodiment. . Accordingly, the same or similar components as those in the first embodiment described above are denoted by the same reference numerals as the corresponding components in FIGS. 1 to 3, and differences from the first embodiment will be described below. .

  As shown in FIGS. 4 and 5, in the present embodiment, the flat pipe wall portions 32 a and 32 b (tube walls) of the bypass pipe 32 through which the exhaust gas that is the heat medium on the high temperature side passes, and the bypass pipe 32 on one side. The pair of high-temperature side heat conductive electrical insulating substrates 44A in contact with the flat tube wall portions 32a and 32b constitute a pair of high-temperature side heat transfer plates 61 involved in heat absorption of the plurality of thermoelectric elements 43. . The other surface side of each high-temperature side heat conductive electrically insulating substrate 44A is joined to a plurality of thermoelectric elements 43 via a circuit electrode portion 42a on the high-temperature side.

  In addition, a pair of low temperatures that contact the inner pipe wall 45a of the cooling water pipe 45 through which engine cooling water, which is a low-temperature side heat medium, and the inner pipe wall 45a (pipe wall) of the cooling water pipe 45 on one surface side respectively. A pair of low-temperature-side heat transfer plates 62 that are involved in the heat radiation of the plurality of thermoelectric elements 43 are configured by the side heat conductive electrically insulating substrate 44B. The other surface side of each low-temperature side heat conductive electrically insulating substrate 44B is joined to a plurality of thermoelectric elements 43 via low-temperature side circuit electrode portions 42b. The plurality of thermoelectric elements 43 are electrically connected in series by a high-temperature circuit electrode portion 42a and a low-temperature circuit electrode portion 42b.

  More specifically, as shown in FIG. 5, the plurality of thermoelectric elements 43 are arranged with a predetermined space in the vertical and horizontal directions in FIG. As shown in FIG. 4, on the other surface of the high temperature side heat conductive electrically insulating substrate 44A, the other surface of the low temperature side heat conductive electric insulating substrate 44B is electrically connected to the circuit electrode portion 42a on the high temperature side. Above, it is electrically connected to the circuit electrode part 42b on the low temperature side. As a result, the plurality of thermoelectric elements 43 are arranged in thermal parallel between the high-temperature-side thermally conductive electrical insulating substrate 44A and the low-temperature-side thermally conductive electrical insulating substrate 44B, while the high-temperature-side circuit electrode unit. 42a and the circuit electrode part 42b on the low temperature side are connected in series. In addition, a set of a plurality of thermoelectric elements 43 connected in series is connected to positive and negative terminals of an electric load (not shown) via a pair of connection terminals 42c.

  The low-temperature-side thermally conductive electrical insulating substrate 44B includes a plurality of contact portions 44e and 44f that are in contact with the plurality of thermoelectric elements 43 through the low-temperature-side circuit electrode portion 42b so as to allow heat conduction, and the plurality of contact portions 44e. , 44f and a non-contact portion 44g that does not contact the plurality of thermoelectric elements 43. Further, the thickness direction of the heat conductive electrically insulating substrate 44B is set to the depth direction so that the non-contact portion 44g of the low temperature side heat conductive electrically insulating substrate 44B is positioned in the vicinity of the four corners of the contact portions 44e and 44f. A plurality of circular through holes 44h are formed. These through-holes 44h penetrate the low-temperature side heat conductive electrically insulating substrate 44B in the plate thickness direction around the contact portions 44e corresponding to each thermoelectric power generation material chip 43c and the cross-hatched portion in FIG. The low-temperature-side thermally conductive electrically insulating substrate 44B also around the contact portion 44f that contacts each pair of thermoelectric power generation material chips 43c (a pair of P-type and N-type semiconductor elements) via the low-temperature-side circuit electrode portion 42b. Is penetrated in the thickness direction.

  4 and 5, the plurality of thermoelectric elements 43 shows a state in which a pair of P-type semiconductor elements and N-type semiconductor elements are electrically connected to each other and at least one set of thermoelectric elements 43 are connected in series. For convenience of illustration, the number of the plurality of thermoelectric elements 43 is limited. That is, each thermoelectric element 43 shown in both figures corresponds to a thermoelectric power generation material chip 43c (P-type semiconductor element or N-type semiconductor element) constituting a part of the thermoelectric power generation module, and is modularized. is not.

  At least one of the inner pipe wall 45a of the cooling water pipe 45 constituting the low temperature side heat transfer plate 62 and the low temperature side heat conductive electrical insulation substrate 44B is a plurality of low temperature side heat conductive electrical insulation substrates 44B. The portions in the vicinity of the contact portions 44e and 44f have lower rigidity than the portions in the vicinity of the non-contact portion 44g, and support is low while the end surface portions 43b (heat transfer surfaces) on the low temperature side of the plurality of thermoelectric elements 43 are in contact with each other. It can be supported with rigidity. For example, as shown in FIG. 4, the inner pipe wall portion 45a of the cooling water pipe 45 can be made thin at each wall surface portion 45a1 of the contact region R1, and a plurality of contacts of the low-temperature side heat conductive electrically insulating substrate 44B. The portions 44e and 44f may be formed thinner than the non-contact portion 44g or may be formed of a material having lower rigidity than the non-contact portion 44g. In the former case, each wall surface portion 45a1 of the contact region R1 is substantially the same area as or slightly wider than any one of the contact portions 44e and 44f, or a plurality of contact portions 44e and 44f. Of these, the contact portions 44e and 44f corresponding to some of the contact portions 44f or a corresponding plurality of contact portions 44f have a larger area. Here, the width of each wall surface portion 45a1 of the contact region R1 may be wider than the contact region of one thermoelectric power generation module, but the non-contact region between the plurality of wall surface portions 45a1 and around each wall surface portion 45a1. A wall surface portion 45a2 of R2 is disposed.

  A plurality of through holes 44h are not formed in the high temperature side heat conductive electrically insulating substrate 44A.

  The plurality of through holes 44h may be non-circular. Further, instead of the plurality of through holes 44h, at least one groove-shaped through hole may be used. When a plurality of through-holes 44h are provided, when the low-temperature side heat conductive electrically insulating substrate 44B and the inner pipe wall 45a of the cooling water pipe 45 are in close contact with each other, the air between them passes through the plurality of through-holes 44h. It can be discharged from the periphery of each joint portion 44e, and it is also possible to suppress a decrease in adhesion between the low-temperature side heat conductive electrical insulating substrate 44B and the inner tube wall portion 45a of the cooling water pipe 45 due to the remaining air. it can.

  In the thermoelectric generator of the present embodiment, the low-temperature heat transfer plate 62 is constituted by the inner tube wall portion 45a of the cooling water pipe 45 and the low-temperature heat conductive electrically insulating substrate 44B in contact therewith, While bringing the plurality of contact portions 44e, 44f of the low temperature side heat conductive electrically insulating substrate 44B constituting the wall surface portion of the contact region R1 into contact with the low temperature side end surface portions 43b (heat transfer surfaces) of the plurality of thermoelectric elements 43. It can be supported with low support rigidity. Therefore, the heat transfer surfaces of the plurality of thermoelectric elements 43 can be stably brought into close contact with the wall surface portion of the contact region R1 of the heat transfer plate 62 on the low temperature side.

  In addition, in this embodiment, since the plurality of through holes 44h are formed in the non-contact part 44g located around the contact parts 44e and 44f of the low-temperature side heat conductive electrically insulating substrate 44B, the low-temperature side heat conduction is performed. It is possible to effectively prevent a decrease in the amount of power generated due to a decrease in the adhesion between the conductive electrical insulating substrate 44B and the inner pipe wall 45a of the cooling water pipe 45.

  Thus, also in this embodiment, the wall surface part of the contact region R1 of the one heat transfer plate 62 that contacts the plurality of thermoelectric elements 43 is made to be less rigid than the wall surface part of the non-contact region R2, and thus the plurality of thermoelectric elements 43 Between the heat transfer surface and the heat transfer plates 61 and 62 on the high temperature side and the low temperature side can be easily absorbed. As a result, it is possible to provide a thermoelectric generator having a simple high power generation efficiency and capable of ensuring a stable contact state between the heat transfer surfaces of the plurality of thermoelectric elements 43 and the heat transfer plates 61 and 62 on the high temperature side and the low temperature side. be able to.

(Third embodiment)
FIG. 6 shows a main part of a thermoelectric generator according to the third embodiment of the present invention.

  Note that the second embodiment described above is partially applied to the low-temperature side heat conductive electrically insulating substrate 44B constituting a part of the wall surface portion of the contact region R1 of the low-temperature side heat transfer plate 62 with the plurality of thermoelectric elements 43. In contrast to the provision of the low-rigidity portion, in the present embodiment, the high-temperature side heat conductive electrically insulating substrate constituting the wall surface portion of the contact region R3 of the high-temperature side heat transfer plate 61 with the plurality of thermoelectric elements 43 is provided. 44A is provided with a partial low rigidity portion. Accordingly, the same or similar components as those in the first and second embodiments described above are denoted by the same reference numerals as the corresponding components in FIGS. 1 to 5 and are different from the second embodiment below. Will be described.

  As shown in FIG. 6, in this embodiment, the pair of high-temperature side heat transfer plates 61 involved in the heat absorption of the plurality of thermoelectric elements 43 are connected to the flat tube wall portions 32a and 32b of the bypass pipe 32 through which the exhaust gas passes. A pair of high-temperature-side heats that are in contact with the flat tube wall portions 32a and 32b of the bypass pipe 32 on one surface side and joined to the plurality of thermoelectric elements 43 via the high-temperature-side circuit electrode portion 42a on the other-surface side. A conductive electrically insulating substrate 44A. Thus, the point comprised by the pipe wall part and heat exchanger plate of piping is the same as that of 2nd Embodiment.

  However, in this embodiment, at least one of the flat tube wall portions 32a and 32b of the bypass pipe 32 and the high temperature side heat conductive electrically insulating substrate 44A constituting the high temperature side heat transfer plate 61 has low rigidity. Yes.

  Specifically, the high-temperature-side thermally conductive electrical insulating substrate 44A includes a plurality of contact portions that are in contact with the plurality of thermoelectric elements 43 through the high-temperature-side circuit electrode portion 42a so as to conduct heat, and a high-temperature-side heat. The conductive electrically insulating substrate 44A has a non-contact portion with the plurality of thermoelectric elements 43. For convenience of explanation, here, a plurality of contact portions of the high temperature side heat conductive electrically insulating substrate 44A are referred to as contact portions 44e and 44f using the reference numerals in FIG. The non-contact portion of the thermally conductive and electrically insulating substrate 44A is referred to as a non-contact portion 44g.

  At least one of the flat tube wall portions 32a and 32b of the bypass pipe 32 constituting the high temperature side heat transfer plate 61 and the high temperature side heat conductive electrically insulating substrate 44A is in the vicinity of the plurality of contact portions 44e and 44f. The portion is lower in rigidity than the portion in the vicinity of the non-contact portion 44g, and can be supported with low support rigidity while contacting the high-temperature side end surface portions 43a (heat transfer surfaces) of the plurality of thermoelectric elements 43. It has become.

  For example, the flat pipe wall portions 32a and 32b of the bypass pipe 32 can be thinned at the portion of the wall surface portion of the contact region R3 that is close to the high temperature side circuit electrode portion 42a, or the high temperature side heat conductive electrical insulation. The plurality of contact portions 44e and 44f of the substrate 44A can be formed thinner than the non-contact portion 44g or made of a material having lower rigidity than the non-contact portion 44g.

  In the present embodiment, similarly to the low-temperature-side thermally conductive electrical insulating substrate 44B in the second embodiment, the non-contact portion 44g with the plurality of thermoelectric elements 43 on the high-temperature-side thermally conductive electrical insulating substrate 44A A plurality of circular through-holes 44h are formed at predetermined intervals with the thickness direction of the heat conductive electrically insulating substrate 44A on the high temperature side as the depth direction. Then, on the other surface side (upper surface side in FIG. 6) of the high temperature side heat conductive electrically insulating substrate 44A, the plurality of thermoelectric elements 43 are spaced apart at equal intervals via the high temperature side circuit electrode portion 42a. Are connected to each other in series, and are thermally bonded in parallel to the high-temperature side heat conductive electrical insulating substrate 44A and the bypass pipe 32. Of course, the plurality of through holes 44h formed in the high temperature side heat conductive electrically insulating substrate 44A may be non-circular or may be formed as at least one groove-shaped through hole.

  On the other hand, the low temperature side thermally conductive electrical insulating substrate 44B in this embodiment is not formed with a plurality of through-holes 44h, like the high temperature side thermally conductive electrical insulating substrate 44A in the second embodiment. It has uniform rigidity throughout the entire region R1.

  The aforementioned contact region R3 is a region in contact with a heat transfer surface group of a plurality of thermoelectric elements 43 electrically connected in series, for example, an island-like collection of a plurality of end surface portions 43a arranged at equal intervals on the same plane. It is formed on both upper and lower sides of the bypass pipe 32 in FIG.

  Further, at least one of the flat tube wall portions 32a and 32b of the bypass pipe 32 and the high temperature side heat conductive electrical insulating substrate 44A constituting the high temperature side heat transfer plate 61 is a contact region of the high temperature side heat transfer plate 61. The function of making the outer peripheral heat transfer wall surface portion of R3 have a lower rigidity than the heat transfer wall surface portion of the low temperature heat conductive electrically insulating substrate 44B that is the inner peripheral wall surface portion of the low temperature heat transfer plate 62. Have both.

  Also in this embodiment, the heat transfer plate 61 on the high temperature side is constituted by the bypass pipe 32 that is a part of the exhaust pipe 31P and the heat conductive electrically insulating substrate 44A on the high temperature side that contacts the bypass pipe 32, and the heat transfer plate. The end surface portion 43b (heat transfer surface) on the high temperature side of the plurality of thermoelectric elements 43 can be supported with low support rigidity while contacting the wall surface portion of the contact region R3 of 61. Therefore, the heat transfer surfaces of the plurality of thermoelectric elements 43 can be stably brought into contact with the wall surface portion of the contact region R3 of the heat transfer plate 61 on the high temperature side.

  In addition, in the present embodiment, even if the end surfaces 43b on the high temperature side of the plurality of thermoelectric elements 43 are inclined or stepped, the contact surface displacement of the end surfaces 43b on the high temperature side is eliminated by the flat tube wall of the bypass pipe 32. It is possible to absorb at least one of the portions 32a and 32b and the high temperature side heat conductive electrically insulating substrate 44A, and the heat transfer surfaces of the plurality of thermoelectric elements 43 are stabilized on the surface of the high temperature side heat conductive electrically insulating substrate 44A. Can be contacted. As a result, the end surfaces 43a and 43b on the high temperature side and the low temperature side of the plurality of thermoelectric elements 43 can come into stable contact with the surfaces of the heat conductive electrical insulating substrates 44A and 44B on the high temperature side and the low temperature side, respectively. The power generation efficiency of the element 43 is improved.

  Further, since the plurality of through holes 44h are formed in the non-contact portion 44g of the high temperature side heat conductive electrically insulating substrate 44A, the high temperature side end surface portions 43b of the plurality of thermoelectric elements 43 are connected to the high temperature side heat conductive electricity. The operation of bringing the surface into contact with the surface of the insulating substrate 44A and the operation of bringing them into contact with the flat tube wall portions 32a and 32b of the bypass pipe 32 can be easily and reliably performed.

  Thus, also in this embodiment, the wall surface portion of the contact region R3 on one side of the one heat transfer plate 61 that contacts the plurality of thermoelectric elements 43 is less rigid than the wall surface portion of the non-contact region R4 on the one surface side. As described above, thermal distortion and contact surface irregularities can be easily absorbed between the heat transfer surfaces of the plurality of thermoelectric elements 43 and the heat transfer plates 61 and 62 on the high temperature side and the low temperature side. As a result, it is possible to provide a thermoelectric generator having a simple high power generation efficiency and capable of ensuring a stable contact state between the heat transfer surfaces of the plurality of thermoelectric elements 43 and the heat transfer plates 61 and 62 on the high temperature side and the low temperature side. be able to.

(Fourth embodiment)
In FIG. 7, the principal part of the thermoelectric power generating apparatus which concerns on 4th Embodiment of this invention is shown.

  In the second and third embodiments described above, the low-rigidity portion is provided only in one of the high-temperature side heat transfer plate 61 and the low-temperature side heat transfer plate 62, whereas in the present embodiment, Both the high-temperature side and low-temperature side heat transfer plates 61 and 62 are provided with low rigidity portions. Accordingly, the same or similar components as those of the second and third embodiments described above are denoted by the same reference numerals as the corresponding components in FIGS. The differences will be described.

  As shown in FIG. 7, in the present embodiment, the high temperature side heat conductive electrically insulating substrate 44A and the low temperature side heat conductive electrically insulating substrate 44B are the low temperature side heat conductive electrically insulating substrate in the second embodiment. 44B and the high temperature side heat conductive electrically insulating substrate 44A in the third embodiment are configured. That is, at least one of the inner pipe wall portion 45a of the cooling water pipe 45 constituting the low temperature side heat transfer plate 62 and the low temperature side heat conductive electrically insulating substrate 44B is the low temperature side heat conductive electric insulating substrate 44B. The portion in the vicinity of the plurality of contact portions 44e and 44f has lower rigidity than the portion in the vicinity of the non-contact portion 44g. Further, at least one of the flat tube wall portions 32a and 32b of the bypass pipe 32 constituting the high temperature side heat transfer plate 61 and the high temperature side heat conductive electric insulating substrate 44A is the high temperature side heat conductive electric insulating substrate 44A. In the vicinity of the plurality of contact portions 44e and 44f, the rigidity is lower than that in the vicinity of the non-contact portion 44g. A plurality of circular through-holes 44h are formed at predetermined intervals in each of the heat conductive electrically insulating substrates 44A and 44B with the plate thickness direction as the depth direction.

  Therefore, also in the present embodiment, the wall surface portions of the contact regions R1, R3 facing each other and the other heat transfer plates 61, 62 that are in contact with the plurality of thermoelectric elements 43 are lower than the wall surface portions of the non-contact regions R2, R4. As rigidity, thermal distortion and contact surface unevenness can be easily absorbed between the heat transfer surfaces of the plurality of thermoelectric elements 43 and the heat transfer plates 61 and 62 on the high temperature side and the low temperature side. As a result, it is possible to provide a thermoelectric generator having a simple high power generation efficiency and capable of ensuring a stable contact state between the heat transfer surfaces of the plurality of thermoelectric elements 43 and the heat transfer plates 61 and 62 on the high temperature side and the low temperature side. be able to.

(Fifth embodiment)
FIG. 8 shows a main part of a thermoelectric generator according to the fifth embodiment of the present invention.

  In contrast to the first embodiment described above, only the wall surface portion 45a1 in the contact region R1 of the inner pipe wall portion 45a (low temperature side heat transfer plate) of the cooling water pipe 45 with the plurality of thermoelectric elements 43 is made thin. In this embodiment, in addition to the configuration of the cooling water pipe 45, the contact region R3 with the plurality of thermoelectric elements 43 of the upper and lower flat exhaust pipes 32U and 32L constituting the heat transfer plate 61 on the high temperature side is not contacted. It is thinner than R4, and the rigidity of the contact wall surface on the heat absorption side is also reduced. Accordingly, the same or similar components as those in the first embodiment described above are denoted by the same reference numerals as the corresponding components in FIGS. 1 to 3, and differences from the first embodiment will be described below. .

  As shown in FIG. 8, in the present embodiment, a plurality of upper and lower flat exhaust pipes 32 </ b> U and 32 </ b> L that are housed in the inner pipe wall portion 45 a of the cooling water pipe 45 and contact each other on one side are provided. An endothermic member 83 having a plurality of endothermic fin portions 83f and a plurality of heat collecting wall portions 83s is provided.

  The exhaust pipes 32U and 32L are made thinner in the wall of the contact region R3 in place of the bypass pipe 32 in the first embodiment, and each of them accommodates a heat absorbing member 83 having a rigidity lower than that of the heat absorbing member 33 in the first embodiment. Is. The degree of thinning here is, for example, the pressure of the exhaust gas through which the flat tube wall portions 32a and 32b, which are the wall portions of the contact region R3 of the exhaust pipes 32U and 32L, pass through the exhaust pipes 32U and 32L, and the installation space 46. The thickness is reduced to such an extent that the adhesiveness between the end surface portion 43a of each thermoelectric element 43 and the flat tube wall portions 32a and 32b of the contact region R3 is enhanced easily according to the pressure.

  Further, in the present embodiment, each thermoelectric element 43 is configured as a thermoelectric power generation module 43M in which a plurality of thermoelectric power generation material chips are integrated with, for example, an electrode plate or a cooling plate.

  Therefore, also in the present embodiment, the wall surface portions (wall surface portions 45a1 and the like) of the contact regions R1, R3 in the cooling water piping 45 and the bypass piping 32 (one and the other heat transfer plates) that are in contact with the plurality of thermoelectric elements 43, Thermal strain between the heat transfer surface of the plurality of thermoelectric elements 43 and the cooling water pipe 45 and bypass pipe 32 serving as heat transfer plates on the high temperature side and the low temperature side is lower than the wall surface portions of the non-contact regions R2 and R4. And can easily absorb contact surface irregularities. As a result, it is possible to provide a simple and high power generation efficiency thermoelectric generator having a configuration capable of ensuring a stable contact state of the heat transfer surfaces of the plurality of thermoelectric elements 43.

  In addition, as in the above-described embodiment, not only a method of forming partial low rigidity portions in the contact regions R1 and R3 by reducing the thickness or making the material low rigidity, but also ribs, bends, reinforcing members It is also conceivable to form a low-rigidity part that is partially made highly rigid by bonding or the like, and that is not made highly rigid.

  Further, the inside of the installation space 46 is depressurized via the one-way valve 47 by a pressure state lower than atmospheric pressure, for example, negative intake pressure, but the installation space 46 is completely sealed after evacuating the installation space 46. It is also possible to connect to other negative pressure sources. Needless to say, a configuration in which a plurality of thermoelectric elements 43, cooling water passages 45c, and the like are stacked in multiple layers can be employed.

  As described above, the present invention provides a thermal strain between the heat transfer surface of a plurality of thermoelectric elements and the heat transfer plates on the high temperature side and the low temperature side by providing a low rigidity portion on the heat transfer plate in contact with the thermoelectric elements. And the contact surface irregularities are easily absorbed, so that the thermoelectric power generation with a simple and high power generation efficiency can secure a stable contact state between the heat transfer surface of the thermoelectric element and the heat transfer plate on the high temperature side and the low temperature side. An apparatus can be provided. The present invention is useful for all thermoelectric generators in which a plurality of thermoelectric elements electrically connected in series are thermally arranged in parallel between a high temperature side heat transfer plate and a low temperature side heat transfer plate. is there.

DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 11 ... Main body block, 11c ... Cylinder, 11w ... Water jacket, 12 ... Radiator, 14 ... Thermostat, 15 ... Water pump, 18 ... EGR cooler, 19 ... Cooling water passage, 19a, 19b ... Branch passage, 24 ... Surge tank, 31 ... Exhaust passage, 31a ... Main passage portion, 31b ... Bypass passage portion, 32 ... Bypass piping, 32a, 32b ... Flat tube wall (high temperature side heat transfer plate, wall surface of contact area) Part), 32c, 32d ... side wall part (wall surface part of non-contact area), 32i ... inner peripheral surface, 32U, 32L ... exhaust pipe, 33, 83 ... heat absorbing member, 33f, 83f ... heat absorbing fin part, 33s, 83s ... Heat collecting wall, 40 ... thermoelectric generator (exhaust heat recirculation and thermoelectric generator, thermoelectric converter), 41 ... exhaust gas control actuator, 41a ... valve element, 4 a, 42b ... circuit electrode part, 43 ... thermoelectric element, 43a, 43b ... end face part (heat transfer surface), 43c ... thermoelectric power generation material chip, 43M ... thermoelectric power generation module, 44A ... high temperature side heat conductive electrically insulating substrate , 44B ... Low-temperature side heat conductive electrical insulating substrate (wall surface part of one heat transfer plate), 44e, 44f ... contact part, 44g ... non-contact part, 44h ... through hole, 45 ... cooling water pipe, 45a ... inside Tube wall portion (low temperature side heat transfer plate, wall surface portion of one heat transfer plate), 45a1 ... wall surface portion (wall surface portion of contact area), 45a2 ... wall surface portion (wall surface portion of non-contact area), 45b ... outer tube Wall part, 45c ... Cooling water passage, 45d ... Side wall part on both ends, 45i ... Inner peripheral surface (one side), 46 ... Installation space, 47 ... One-way valve (check valve), 49 ... Pressure reducing mechanism, 61 ... High temperature side Heat transfer plate, 62 ... low temperature side heat transfer plate, R1, R3 ... contact area, R , R4 ... non-contact area

Claims (5)

A plurality of thermoelectric elements each having a heat transfer plate on the high temperature side and a heat transfer plate on the low temperature side, and a heat absorption surface in contact with the heat transfer plate on the high temperature side and a heat dissipation surface in contact with the heat transfer plate on the low temperature side, respectively. Prepared,
A thermoelectric generator that generates electric power according to a temperature difference between the heat absorption surface and the heat dissipation surface by the thermoelectric element,
At least one of the high temperature side heat transfer plate and the low temperature side heat transfer plate has a contact area in contact with the thermoelectric element and a non-contact area not in contact with the thermoelectric element, and the contact area The thermoelectric power generator is characterized in that the wall surface portion has a lower rigidity than the wall surface portion of the non-contact region.   A closed installation space for installing the thermoelectric element is formed between the high temperature side heat transfer plate and the low temperature side heat transfer plate, and the pressure inside the installation space is maintained at a pressure lower than atmospheric pressure. The thermoelectric power generator according to claim 1.   The one heat transfer plate causes the thermoelectric element to absorb heat via the high temperature side heat transfer plate, and the low temperature side heat dissipates from the thermoelectric element via the low temperature side heat transfer plate. The thermoelectric generator according to claim 1, wherein the thermoelectric generator is configured by a pipe wall of a pipe through which any one of the heat medium passes.   The one heat transfer plate is either one of a high temperature side heat medium that absorbs heat to the high temperature side heat transfer plate and a low temperature side heat medium that releases heat from the low temperature side heat transfer plate. It is comprised by the pipe wall of the piping which lets a heat medium pass, and the heat conductive electrical insulation board | substrate which contacts the pipe wall of the said piping on the one surface side, and contacts the said thermoelectric element on the other surface side. Item 3. The thermoelectric generator according to item 1 or item 2. The plurality of thermoelectric elements are arranged at intervals on the other surface side of the thermally conductive electrically insulating substrate,
The thermoelectric generator according to claim 4, wherein the thermally conductive electrically insulating substrate has a through hole penetrating in a thickness direction in a non-contact portion with the plurality of thermoelectric elements.

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