JP6173932B2 - Thermoelectric generator - Google Patents

Description

  The present invention relates to a thermoelectric power generation apparatus that generates power using heat of exhaust gas discharged from an internal combustion engine.

  There is known a thermoelectric generator that converts a temperature difference into electric power by generating a Seebeck effect (reverse action of the Peltier effect) in a Peltier element. In general, the thermoelectric generator is configured to cause a Peltier element to generate power in accordance with a temperature difference between both ends of the Peltier element by contacting both ends of the Peltier element with a high temperature side member and a low temperature side member.

  Thermoelectric power generation elements include those having excellent heat resistance but relatively low power generation efficiency, and those having poor heat resistance but relatively high power generation efficiency. As a thermoelectric power generation apparatus using a thermoelectric power generation element having excellent heat resistance, for example, there is one that is attached to an exhaust heat recovery apparatus of an internal combustion engine for a vehicle.

  As this type of thermoelectric generator, for example, a cooling water pipe for exhaust heat recovery is arranged on the outer periphery of the exhaust pipe, and a thermoelectric module is arranged between the cooling water pipe and the exhaust pipe, so that the thermoelectric module A device that generates power is known (for example, see Patent Document 1 below).

  Further, in the thermoelectric generator described in Patent Document 2 below, a disk-shaped heat exchanger is provided around the pipe through which the exhaust gas passes, and cooling water is passed through the disk-shaped member, and the surface of the disk-shaped member Is provided with a thermoelectric generator. Exhaust gas is passed between adjacent thermoelectric power generation elements, and power is generated using the temperature difference between the exhaust gas side and the cooling water side.

JP 2007-014161 A Special table 2011-52481 gazette

  The thermoelectric power generation device described in Patent Document 2 discloses only passing exhaust gas between the thermoelectric power generation elements adjacent to each other, and does not disclose any further improvement in power generation efficiency.

  The present invention has been made in view of such problems, and an object of the present invention is a thermoelectric power generation apparatus that generates power using heat of exhaust gas discharged from an internal combustion engine, and functions as an exhaust heat recovery apparatus. The object is to provide a thermoelectric generator capable of further improving the power generation efficiency.

  In order to solve the above-described problems, a thermoelectric power generation device according to the present invention is a thermoelectric power generation device that generates power using the heat of exhaust gas discharged from an internal combustion engine, and (1) receives exhaust gas flowing from the upstream side. An inner member that forms a part of the main flow path connecting the receiving port and the main outlet that sends the received exhaust gas downstream; and (2) disposed between the inner member and the inner member. And (3) a heat exchanger that is arranged so as to surround the inner member in the heat exchange flow path and exchanges heat between the exhaust gas and the heat exchange medium, (4) And a thermoelectric generator module provided in contact with the heat exchanger. In the present invention, the heat exchange flow path is a first heat exchange flow path formed between the heat exchanger and the inner member, and a second heat exchange flow formed between the heat exchanger and the outer member. The exhaust gas flows out from the heat exchange outlet to the heat exchange flow path, and the exhaust gas flowed out to the heat exchange flow path flows in the radial direction from the inside to the outside of the heat exchanger to perform the first heat exchange. It is comprised from the flow path to the 2nd heat exchange flow path. Furthermore, the thermoelectric power generation device according to the present invention includes an exhaust gas guide portion provided so that the exhaust gas is guided to the vicinity of the thermoelectric power generation module while flowing from the first heat exchange channel to the second heat exchange channel.

  According to the present invention, since the exhaust gas flows from the inner first heat exchange channel to the outer second heat exchange channel with respect to the heat exchanger provided with the thermoelectric power generation module, the higher temperature exhaust gas Can be supplied to the thermoelectric generator module. Further, since the exhaust gas guide portion is provided so that the exhaust gas is led to the vicinity of the thermoelectric power generation module while the exhaust gas flows from the first heat exchange flow path to the second heat exchange flow path, the thermoelectric power generation module is provided. The exhaust gas can be supplied efficiently. Since the heat exchanger used in the present invention is disposed so as to surround the inner member in the heat exchange flow path, the cross section can be circular or a shape equivalent thereto. On the other hand, the thermoelectric power generation module does not necessarily have a circular cross section or a shape similar thereto, and may have a rectangular shape. In such a case, the thermoelectric power generation modules are arranged in a scattered manner in the heat exchanger, and the power generation efficiency cannot be improved without any ingenuity. Therefore, in the present invention, by providing the exhaust gas guide portion described above, exhaust gas can be supplied aiming at the place where the thermoelectric power generation module is provided, and the power generation efficiency can be reliably increased. It is possible to provide a thermoelectric power generator with improved power generation efficiency while having the function of a heat recovery device.

  According to the present invention, a thermoelectric power generator that generates power using the heat of exhaust gas discharged from an internal combustion engine, and has a function of an exhaust heat recovery device, and can further improve power generation efficiency. Can be provided.

It is a perspective view showing a schematic structure of a thermoelectric power generator which is an embodiment of the present invention. It is a partial schematic sectional drawing of the thermoelectric power generating apparatus which is embodiment of this invention. It is a schematic sectional drawing of the thermoelectric power generation module shown in FIG. It is a schematic sectional drawing which shows the II cross section of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  With reference to FIG. 1, a thermoelectric generator according to an embodiment of the present invention will be described. FIG. 1 is a perspective view showing a schematic configuration of a thermoelectric generator HE that is an embodiment of the present invention. The thermoelectric generator HE is a so-called exhaust heat recovery device provided with a thermoelectric generator module. The thermoelectric generator HE, which also has an aspect as an exhaust heat recovery device, is mounted on an automobile, for example, and generates heat by a thermoelectric generator module while exchanging heat between exhaust gas discharged from an automobile internal combustion engine and a heat exchange medium. Also do. The thermoelectric generator HE is provided with a receiving port HEa that receives exhaust gas flowing from the upstream side, and a main sending port HEb that sends the received exhaust gas to the downstream side.

  The thermoelectric generator HE includes an upstream side exhaust pipe 10, an inner cylinder 11, an outer cylinder 20, a medium inlet part 21, a medium outlet part 22, an upstream end plate 24, and a switching valve 30. . The upstream side exhaust pipe 10 and the inner cylinder 11 are connected to each other and constitute a main flow path through which exhaust gas flows. Therefore, the inner cylinder 11 forms a part of the main flow path that connects the receiving port HEa and the main delivery port HEb.

  The outer cylinder 20 is disposed so as to surround the inner cylinder 11 on the same axis, and forms a heat exchange channel with the inner cylinder 11. The medium inlet portion 21 is a portion serving as an inlet for supplying a heat exchange medium to a heat exchanger (not explicitly shown in FIG. 1) in the heat exchange flow path. The medium outlet portion 22 is a portion serving as an outlet for discharging the heat exchange medium supplied from the medium inlet portion 21 and exchanging heat with the exhaust gas. As the heat exchange medium, a liquid used for cooling the internal combustion engine is used.

  The switching valve 30 is provided at the main delivery port HEb on the downstream side of the inner cylinder 11, and is a valve that opens and closes the main channel end.

  Next, the thermoelectric generator HE will be described with reference to FIG. FIG. 2 is a partial schematic cross-sectional view of the thermoelectric generator HE. As already described, the upstream side exhaust pipe 10 and the inner cylinder 11 are connected to each other to form the upstream side main flow path ZA. The outer cylinder 20 is arranged so as to share the central axis with the inner cylinder 11, and the inner diameter of the outer cylinder 20 is configured to be larger than the outer diameter of the inner cylinder 11. Therefore, a space is formed between the inner cylinder 11 and the outer cylinder 20, and a heat exchange channel ZB is formed.

  An upstream end plate 24 is disposed so as to connect the inner cylinder 11 and the outer cylinder 20. The upstream end plate 24 is an annular plate that is fixed so as to connect the vicinity of the upstream end of the outer cylinder 20 and the outer periphery of the inner cylinder 11. The upstream end plate 24 is disposed so as to close the upstream end of the heat exchange channel ZB.

  Thus, by arranging the upstream end plate 24 that closes the upstream end of the heat exchange flow path ZB between the inner cylinder 11 and the outer cylinder 20, the exhaust gas enters the heat exchange flow path ZB from the upstream side. This can be reliably prevented, and the exhaust gas flow in the first mode in which the exhaust gas flows from the side outlet 112 into the heat exchange channel ZB can be secured.

  A heat exchanger 40 is disposed in the heat exchange channel ZB. The heat exchanger 40 is disposed so as to surround the inner cylinder 11 in the heat exchange flow path ZB, has an outer shape that is cylindrical, and performs heat exchange between the exhaust gas and the heat exchange medium. . The heat exchanger 40 is disposed so as to be separated from the inner cylinder 11 by a predetermined distance, and is disposed so as to be separated from the outer cylinder 20 by a predetermined distance. By arranging the heat exchanger 40 in this way, a first heat exchange flow path ZB1 is formed between the heat exchanger 40 and the inner cylinder 11, and between the heat exchanger 40 and the outer cylinder 20. Is formed with a second heat exchange flow path ZB2.

  At the downstream end of the inner cylinder 11, a side outflow port 112 (thermal AC outlet) for allowing the exhaust gas to flow out from the upstream main channel ZA to the first heat exchange channel ZB1 is formed. The side outlet 112 is formed on the main outlet HEb side with respect to the inlet HEa. More specifically, the side outlet 112 is formed so that the side surface of the inner cylinder 11 is open near the downstream end of the heat exchange flow path ZB.

  A downstream side between the inner cylinder 11 and the outer cylinder 20 closes the downstream end of the first heat exchange flow path ZB1 so that the exhaust gas flowing out from the side outlet 112 is guided to the first heat exchange flow path ZB1. An end plate 25 is disposed. The downstream end plate 25 is disposed so as to connect the inner cylinder 11 or the switching valve 30 on the downstream side of the side outlet 112 and the downstream end of the heat exchanger 40. On the other hand, the downstream end plate 25 is not connected to the outer cylinder 20, and a sub delivery port 201 is formed between the downstream end plate 25 and the outer cylinder 20.

  Thus, by arranging the downstream end plate 25 that closes the downstream end of the first heat exchange flow path ZB1 between the inner cylinder 11 and the outer cylinder 20, the exhaust gas flowing out from the side outlet 112 can be reliably ensured. Can be introduced into the first heat exchange flow path ZB1. Accordingly, the exhaust gas flowing out from the side outlet 112 first enters the first heat exchange flow path ZB1, performs heat exchange while traversing the heat exchanger 40 in the radial direction, and flows into the second heat exchange flow path ZB2. A mode exhaust gas flow can be secured. The exhaust gas that has flowed into the second heat exchange flow path ZB2 flows from the sub delivery port 201 to the downstream main flow path ZC.

  A switching valve 30 is arranged at the downstream end of the inner cylinder 11 and at the boundary position between the upstream main flow path ZA and the downstream main flow path ZC. A downstream exhaust pipe 12 is provided so as to cover the switching valve 30 and form the downstream main flow path ZC. The downstream exhaust pipe 12 is a pipe line connected to the downstream side of the outer cylinder 20.

  With the configuration described above, the first mode in which the exhaust gas received in the upstream main flow path ZA passes through the upstream main flow path ZA and flows to the main outlet HEb by opening and closing the switching valve 30 serving as a switch, and the upstream main flow The second mode in which the exhaust gas received in the passage ZA is allowed to flow from the upstream main passage ZA to the sub-feed outlet 201 via the heat exchange passage ZB can be selectively performed.

  In the thermoelectric generator HE, as described above, the first heat exchange channel ZB1 is formed between the heat exchanger 40 and the inner cylinder 11, and the second heat is passed between the heat exchanger 40 and the outer cylinder 20. The exchange flow path ZB2 is formed, the side outlet 112 from which the exhaust gas flows from the upstream main flow path ZA to the first heat exchange flow path ZB1 is upstream, and the main outlet HEb of the first heat exchange flow path ZB1 is downstream. Is formed. Further, in the thermoelectric generator HE, in the second mode, the exhaust gas flows out from the side outlet 112 to the heat exchange channel ZB, and the exhaust gas flowing out to the heat exchange channel ZB flows from the first heat exchange channel ZB1. The heat exchanger 40 flows in the radial direction from the inside to the outside and reaches the second heat exchange channel ZB2, and heat exchange is performed in the heat exchanger 40 during the flow.

  According to the present embodiment, the side outlet 112 from which the exhaust gas flows from the upstream main passage ZA to the first heat exchange passage ZB1 is formed at the main feed outlet HEb side end of the first heat exchange passage ZB1. Therefore, the side outlet 112 can be formed in the vicinity of the switching valve 30. Thus, by devising the arrangement of the side outlet 112, when the switching valve 30 is operated to form the first mode exhaust gas flow, the side outlet 112 passes through the heat exchange channel ZB. Thus, the pressure difference between the path leading to the sub-feed port 201 and the main flow path from the upstream main flow path ZA to the downstream main flow path ZC can be reduced. Therefore, in the first mode, the exhaust gas does not enter the heat exchange flow path ZB side, and can flow as it is from the main outlet HEb toward the downstream main flow path ZC via the main flow path.

  The heat exchanger 40 has a plurality of heat exchanger unit parts 23 that are formed along the inner cylinder 11 and the outer cylinder 20 and that can be stacked and arranged at a predetermined interval from each other.

  The plurality of heat exchanger unit parts 23 are stacked apart from each other to form an internal heat exchange flow path 401. The heat exchanger unit part 23 is an annular disk member having a hole formed in the center. The heat exchanger unit part 23 includes an annular side part 231a, an inner annular side part 231b, an annular side part 231c, and an outer annular side part 231d so as to form an internal space 232 through which the heat exchange medium flows. Are connected.

  The annular side portion 231a and the annular side portion 231c are side surfaces that are arranged opposite to each other and have the same shape. The annular side portion 231a and the annular side portion 231c are annular disk members each having a hole formed in the central portion.

  The inner annular side portion 231b is an annular member that connects the inner circular portion of the annular side portion 231a and the inner circular portion of the annular side portion 231c. The outer annular side portion 231d is an annular member that connects the outer circular portion of the annular side portion 231a and the outer circular portion of the annular side portion 231c. The internal space 232 is formed by connecting the annular side portion 231a, the inner annular side portion 231b, the annular side portion 231c, and the outer annular side portion 231d. It should be noted that in what manner the annular side portion 231a, the inner annular side portion 231b, the annular side portion 231c, and the outer annular side portion 231d are connected in consideration of manufacturability and the like. It is arbitrarily selected.

  The heat exchange medium flowing in from the medium inlet portion 21 flows into each of the internal spaces 232 of the heat exchanger unit part 23 configured as described above, and the flowed heat exchange medium flows out after exchanging heat with the exhaust gas. Then, it flows out from the medium outlet 22. As described above, in the heat exchanger 40, the heat exchange medium flows inside the heat exchanger single component 23, while the exhaust gas flows in the internal heat exchange flow path 401 between the plurality of heat exchanger single components 23. Heat exchange. The medium flow path from the medium inlet portion 21 to the medium outlet portion 22 is fixed so as to penetrate the upstream end plate 24. Since the upstream end plate 24 is fixed to the inner cylinder 11 and the outer cylinder 20, the medium flow path from the medium inlet portion 21 to the medium outlet portion 22 is interposed between the inner cylinder 11 and the outer cylinder with the upstream end plate 24 interposed therebetween. It is fixed to the cylinder 20.

  In the present embodiment, the thermoelectric power generation module 50 is provided so that thermoelectric power generation can be performed by a temperature difference between the heat exchange medium flowing through the internal space 232 of the heat exchanger unit part 23 and the exhaust gas flowing through the internal heat exchange flow path 401. It has been.

  A specific configuration of the thermoelectric power generation module 50 will be described with reference to FIG. FIG. 3 is an enlarged view of the vicinity of the heat exchanger single component 23 and the thermoelectric power generation module 50 shown in FIG. 2, and the thermoelectric power generation module 50 is also a cross-sectional view.

  As illustrated in FIG. 3, the thermoelectric power generation module 50 includes a pair of thermoelectric power generation elements 501 a and 501 c, a cover 502, and a cover 503. The thermoelectric power generation element 501 a is provided so as to abut on the annular side portion 231 a of the heat exchanger single component 23. The thermoelectric power generation element 501c is provided so as to contact the annular side portion 231c of the heat exchanger single component 23.

  Since it is not preferable that the thermoelectric generators 501a and 501c are in direct contact with the exhaust gas, they are covered with the covers 502 and 503. Specifically, the cover 502 is disposed so as to cover the thermoelectric power generation element 501a and form a closed space 502a between the annular side portion 231a of the heat exchanger single component 23. Similarly, the cover 503 is disposed so as to cover the thermoelectric power generation element 501c and to form a closed space 503a between the annular portion 231c of the heat exchanger single component 23. An inert gas is sealed in the closed spaces 502a and 503a.

  The thermoelectric power generation elements 501a and 501c of the present embodiment have a rectangular parallelepiped shape, and the thermoelectric power generation module 50 including the covers 502 and 503 also has a rectangular parallelepiped shape. How the thermoelectric power generation module 50 having a substantially rectangular parallelepiped shape is arranged with respect to the substantially circular heat exchanger single component 23 will be described with reference to FIG. FIG. 4 is a cross-sectional view showing a cross section taken along the line II of FIG.

  As shown in FIG. 4, four thermoelectric power generation modules 50 are provided in the circumferential direction of the substantially circular heat exchanger single component 23. Naturally, there is a gap between the adjacent thermoelectric power generation modules 50, so if exhaust gas is introduced into the internal heat exchange flow path 401 (see FIG. 2), the exhaust gas also flows into the gap, and the thermoelectric power generation module 50 is efficiently located in the vicinity. It is not possible to introduce exhaust gas into

  Therefore, in this embodiment, a guide side wall 60 is provided as an exhaust gas guide portion. The guide side wall 60 is disposed so as to guide the exhaust gas flowing from the heat exchange channel ZB1 to the heat exchange channel ZB2 to the vicinity of the thermoelectric power generation module 50. Specifically, the guide side wall 60 extends from the inner cylinder 11 toward the outer cylinder 20 and is disposed along one of the left and right ends of the thermoelectric power generation module 50 in that direction. For one thermoelectric power generation module 50, a guide side wall 60 provided along one end side and a guide side wall 60 provided along the other end side are arranged. Moreover, the guide side wall 60 along one end side of the adjacent thermoelectric power generation module 50 and the guide side wall 60 along the other end side are connected to each other on the inner cylinder 11 side so as to be L-shaped in cross section. In addition, the exhaust gas does not flow in a region where the thermoelectric power generation module 50 is not disposed.

  The guide side wall 60 may be formed as a component separate from the heat exchanger single component 23 and attached to the heat exchanger single component 23 or may be provided integrally with the heat exchanger single component 23. When the guide side wall 60 is provided integrally with the heat exchanger single component 23, it is also preferable that the guide side wall 60 be formed by providing irregularities on the annular side portions 231a and 231c. For example, it is also preferable to form the recesses in the annular side portions 231a and 231c and arrange the thermoelectric power generation module 50 in the recesses so that the recess side walls become the guide side walls 60.

  Although not explicitly shown in the drawing, the plurality of thermoelectric power generation modules 50 are electrically connected directly, and are configured such that electricity can be taken out to the outside by a power take-out line (not shown).

  The above embodiment is merely an example, and various omissions, replacements, and changes can be made without departing from the scope of the invention.

HE: Thermoelectric power generator 10: Upstream exhaust pipe 11: Inner cylinder 12: Downstream exhaust pipe 20: Outer cylinder 21: Medium inlet 22: Medium outlet 23: Heat exchanger single component 24: Upstream end plate 25: Downstream end plate 30: Switching valve ZA: Upstream main channel ZB: Heat exchange channel ZB1: Heat exchange channel ZB2: Heat exchange channel ZC: Downstream main channel 112: Side outlet 113: Main outlet 201: Sub-outlet 231a: annular side portion 231b: inner annular side portion 231c: annular side portion 231d: outer annular side portion 232: internal space 40: heat exchanger 401: internal heat exchange channel 50: thermoelectric power generation module 501a, 501c: thermoelectric power generation element 502: cover 502a: internal space 503: cover 503a: internal space 60: guide side wall

Claims (1)

A thermoelectric generator that generates power using heat of exhaust gas discharged from an internal combustion engine,
An inner member that forms a part of the main flow path connecting the receiving port that receives the exhaust gas flowing from the upstream side and the main sending port that sends the received exhaust gas to the downstream side;
An outer member arranged to surround the inner member and forming a heat exchange channel with the inner member;
A heat exchanger disposed so as to surround the inner member in the heat exchange flow path, and performing heat exchange between the exhaust gas and the heat exchange medium;
A thermoelectric generation module provided in contact with the heat exchanger,
The heat exchange flow path includes a first heat exchange flow path formed between the heat exchanger and the inner member, and a second heat exchange flow formed between the heat exchanger and the outer member. Road, and
Exhaust gas flows out from the heat exchange outlet to the heat exchange flow path, and the exhaust gas flowed out to the heat exchange flow path flows in the radial direction from the inside to the outside of the heat exchanger and from the first heat exchange flow path. Configured to reach the second heat exchange flow path,
A thermoelectric power generator comprising an exhaust gas guide portion provided so as to be led to the vicinity of the thermoelectric power generation module while exhaust gas flows from the first heat exchange channel to the second heat exchange channel. .

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