JP2008072775A - Exhaust heat energy recovery system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust heat energy recovery system in which heat is transported effectively to a thermoelectric module and power generation efficiency is enhanced by thermoelectric conversion. <P>SOLUTION: The exhaust heat energy recovery system has such a structure as a plurality of exhaust pipes 10, thermoelectric modules 20, and cooling pipes 30 are stacked with the exhaust pipes 10 and the thermoelectric modules 20 being held between the cooling pipes 30. The exhaust pipe 10 has a rectangular profile of passage in the cross-section intersecting the flow direction E of exhaust gas perpendicularly, and the cooling pipe 30 similarly has a rectangular profile of passage in the cross-section intersecting the flow direction C of cooling medium perpendicularly. The thermoelectric module 20 is planar and arranged in contact with a pair of opposing outer side faces of the exhaust pipe 10 having a rectangular cross-sectional profile of passage, i.e. the outer surfaces of the upper and lower surface of the rectangular exhaust pipe 10. The cooling pipes 30 are holding the exhaust pipes 10 through the thermoelectric modules 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust heat energy recovery apparatus, and more particularly to an exhaust heat energy recovery apparatus that performs exhaust heat power generation using a thermoelectric module.

In automobile engines, part of the thermal energy generated by the explosion and combustion of the mixed gas is converted into motive power and used for driving, but most of the generated heat is discarded through cooling water and exhaust. If this heat can be converted into power, the efficiency of the engine increases.
In recent years, since thermoelectric conversion can directly convert a temperature difference into electricity, attempts have been actively made to recover energy by exhaust heat power generation using a thermoelectric element.

For example, as an exhaust heat power generation device that generates heat using the Seebeck effect from the temperature difference between the thermoelectric element outside the engine exhaust pipe and the temperature difference between the thermoelectric element and the outside, the exhaust pipe through which exhaust gas discharged from an automobile engine flows A structure in which a plurality of thermoelectric conversion elements are arranged in an annular shape is disclosed (for example, see Patent Document 1).
Further, an exhaust heat power generation apparatus in which a box-shaped heat absorption cylinder is provided in an exhaust pipe through which exhaust gas discharged from an automobile engine flows is disclosed (for example, see Patent Document 2).

In addition, a thermoelectric element is installed outside the exhaust pipe, heat collecting fins are provided inside the exhaust pipe to collect heat from the exhaust pipe, and heat radiation fins are provided further outside the thermoelectric element to generate a temperature difference generated in the thermoelectric element. There is also disclosed an exhaust heat power generation device that has been devised to increase the power (see, for example, Patent Document 3).
Further, a method of mechanically fixing the cooling unit provided outside the exhaust pipe (see, for example, Patent Document 4) or a device for improving the power generation efficiency by closely fixing the joint part of the module (for example, Patent Document) 5) has been proposed.

However, it is difficult to effectively transfer the heat flowing through the exhaust pipe to the thermoelectric module by the above-described method. On the other hand, a method has been proposed in which the inside of the exhaust pipe is divided to provide a bottleneck, and heat is transferred to a thermoelectric module provided in the bottleneck (see, for example, Patent Document 6).
In addition, in order to convert exhaust heat to electricity using a thermoelectric element, the exhaust heat is transmitted to the thermoelectric element, and the heat flow in the low temperature part of the thermoelectric element is quickly dissipated into the exhaust passage through which engine exhaust is guided. A structure in which the low temperature portion is in contact with the cooling water flow path in which the high temperature portion of the thermoelectric element is in contact and is communicated with the radiator and through which the cooling water dedicated to exhaust heat power generation is guided is also disclosed.
JP 61-254082 A JP 63-262075 A Japanese Patent Laid-Open No. 11-122960 JP 2000-286469 A JP 2002-325470 A Japanese Patent Laid-Open No. 2005-057908 Japanese Patent Application Laid-Open No. 8-261064

  However, in the above-described conventional exhaust heat power generation device or the like, in order to give a temperature difference to the thermoelectric element, a thermoelectric module is attached to the exhaust pipe, the joint portion of the module is closely fixed and heat transfer is further improved, and the heat transfer is further concentrated inside the exhaust pipe. A heat fin is provided to collect heat, and a mechanism for dissipating heat by providing a heat dissipating fin on the outside of the module or a mechanism for cooling is employed, and the power generation efficiency is still not sufficient.

  The present invention has been made in view of such problems of the prior art, and its object is to effectively transfer heat to a thermoelectric module to improve power generation efficiency by thermoelectric conversion. It is to provide an energy recovery device.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by increasing the surface area of the passage through which exhaust heat passes and installing a plurality of thermoelectric modules on the surface. The present invention has been completed.

That is, the exhaust heat energy recovery apparatus of the present invention includes a plurality of rectangular exhaust pipes for exhaust gas circulation, plate-like thermoelectric modules provided in contact with a pair of opposed outer surfaces of these rectangular exhaust pipes, and these plates A rectangular cooling pipe for circulating a cooling medium provided in contact with the thermoelectric module,
The rectangular exhaust pipe and the plate-shaped thermoelectric module have a structure sandwiched between the rectangular cooling pipes.

Moreover, the suitable form of the waste heat energy recovery apparatus of this invention is characterized by the said rectangular cooling pipes being fastened by the fastening member.
Furthermore, another preferred embodiment of the exhaust heat energy recovery apparatus of the present invention uses three or more bars provided with screws for mechanical tightening of the rectangular exhaust pipe, the plate-like thermoelectric module, and the rectangular cooling pipe. It is characterized by being carried out.

  According to the present invention, since the surface area of the passage through the exhaust heat is increased and a plurality of thermoelectric modules are installed on the surface, heat is effectively transferred to the thermoelectric module to improve power generation efficiency by thermoelectric conversion. An exhaust heat energy recovery apparatus can be provided.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view showing an embodiment of the exhaust heat energy recovery apparatus of the present invention.
In this figure, the exhaust heat energy recovery apparatus is configured by laminating a plurality of exhaust pipes 10, a thermoelectric module 20, and a cooling pipe 30, and the exhaust pipe 10 and the thermoelectric module 20 are formed by a cooling pipe 30. It has a sandwiched structure.

Here, the exhaust pipe 10 has a rectangular passage shape in a cross section orthogonal to the exhaust gas flow direction E, and the cooling pipe 30 similarly has a rectangular passage shape in a cross section orthogonal to the cooling medium flow direction C. (Not shown).
Further, the thermoelectric module 20 has a plate shape, and as described above, a pair of opposed outer surfaces of the exhaust pipe 10 having a rectangular cross-sectional shape, that is, outside the upper surface of the rectangular exhaust pipe 10 in this embodiment. It is disposed in contact with the outer surface of the surface and the lower surface.
The cooling pipe 30 is disposed in contact with each of these two thermoelectric modules 20. In other words, the cooling pipe 30 sandwiches the exhaust pipe 10 via the thermoelectric modules 20 and 20. .

In the present embodiment, since a plurality of exhaust pipes 10 are provided, the area where the exhaust pipes contact the cooling pipe 30 via the thermoelectric module 20 is increased. Therefore, the exhaust heat from the exhaust pipe 10 can be efficiently transmitted to the thermoelectric module.
In the present embodiment, the exhaust pipe 10 and the cooling pipe 30 form a rectangular tube (square tube), and the thermoelectric module 20 has a plate shape. Therefore, these three types of members can be mechanically easily and firmly connected, and can be easily and firmly connected using a fastening member such as a screw or a bolt, for example.

In general, in a conventional exhaust heat energy recovery apparatus, an exhaust pipe generates a temperature distribution when exposed to a high temperature, and causes non-uniform thermal expansion according to the temperature distribution. For this reason, a gap is generated at the joint between the thermoelectric module and the exhaust pipe and heat transfer is deteriorated.
On the other hand, in the exhaust heat energy recovery apparatus of the present embodiment, since the three types of members can be firmly connected and integrated as described above, the generation of gaps due to thermal deformation can be suppressed, and good heat transfer can be realized. .

(Embodiment 2)
FIG. 2 is a perspective view showing another embodiment of the exhaust heat energy recovery device of the present invention, and shows a state where the exhaust heat energy recovery device is attached to an exhaust pipe of an engine. FIG. 3 is a cross-sectional view taken along the line III-III of the exhaust heat energy recovery apparatus shown in FIG.
In addition, in the following description, the same code | symbol is attached | subjected about the member and element mentioned above, and the description is abbreviate | omitted.

In FIG. 2, the exhaust heat energy recovery apparatus 1 is provided with an intake manifold 50 and an exhaust manifold 52 having four flow paths, and accordingly, four rectangular exhaust pipes 10 are provided. Five rectangular cooling pipes 30 are provided in order to sandwich and fix the four rectangular exhaust pipes 10 (and the thermoelectric module 20) (see FIG. 3).
A cooling medium (not shown) is circulated and circulated in the five rectangular cooling pipes 30 via the cooling pump 40 (see FIG. 2).

In FIG. 3, thermoelectric modules 20 are disposed in contact with both outer surfaces of the four rectangular exhaust pipes 10, and rectangular cooling pipes 30 are disposed in contact with the thermoelectric modules. And the thermoelectric module 20 are sandwiched between rectangular cooling pipes 30.
In addition, the rectangular cooling pipes 30 are fastened by bolts 70 via a heat insulating material 60, and heat transfer of the exhaust pipe 10, the thermoelectric module 20, and the cooling pipe 30 is improved by such fastening. With such a structure, since heat can be effectively supplied to a plurality of thermoelectric modules, the amount of heat flowing through the thermoelectric modules can be increased, and the output by thermoelectric conversion can be increased.

(Embodiment 3)
FIG. 4 shows still another embodiment of the exhaust heat energy recovery apparatus of the present invention, and is a partial sectional view showing a part corresponding to a part of the exhaust heat energy recovery apparatus shown in FIG.
In the figure, fins 11 for efficiently transferring heat to the outer surface are erected on the inner side surface of the rectangular exhaust pipe 10, and similar fins 31 also dissipate heat on the inner side surface of the rectangular cooling pipe 30. It is established as a purpose. The cooling pipe 30 is provided with a coupling portion 33 to which the bolt 70 is attached.

In addition, the thermoelectric module 20 is installed in a form sandwiched between the rectangular exhaust pipe 10 and the rectangular cooling pipe 30, but in this embodiment, the P-type thermoelectric semiconductor 21 and the N-type thermoelectric semiconductor 22 are erected alternately. These are electrically connected to the electrode 23 at the low temperature part and the high temperature part. In addition, an insulator 25 is provided on the outside thereof, and the rectangular exhaust pipe 10 and the rectangular cooling pipe 30 are insulated.
By providing the fins as described above, the heat transfer efficiency can be further improved.

Although the present invention has been described in detail with some preferred embodiments, the present invention is not limited to these embodiments.
For example, a rectangular exhaust pipe or the like has a rectangular cross-sectional shape, but may be a square. Moreover, as a connection structure of the exhaust pipe, the thermoelectric module, and the cooling pipe, it is sufficient that the three members are connected to a certain extent in a state where heat can be transferred, and may be laminated or juxtaposed.
Further, the fin is not an essential member. Further, if three or more rods provided with screws are used and the three elements of the rectangular exhaust pipe, the thermoelectric module and the rectangular cooling pipe are mechanically tightened, the integration of these three elements can be promoted.

1 is a schematic cross-sectional view showing an embodiment of an exhaust heat energy recovery device of the present invention. It is a perspective view which shows other embodiment of the waste heat energy recovery apparatus of this invention. It is sectional drawing in the III-III cut surface of the waste heat energy recovery apparatus shown in FIG. It is a fragmentary sectional view which shows other embodiment of the waste heat energy recovery apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust heat energy recovery apparatus 10 Rectangular exhaust pipe 11 Fin 20 Thermoelectric module 21 P-type thermoelectric semiconductor 22 N-type thermoelectric semiconductor 23 Electrode 25 Insulator 30 Rectangular cooling pipe 31 Fin 33 Joint part 40 Cooling pump 50 Intake manifold 52 Exhaust manifold 60 Insulation 70 bolts of material

Claims (3)

Plural rectangular exhaust pipes for exhaust gas distribution, plate-like thermoelectric modules provided in contact with a pair of opposed outer surfaces of the rectangular exhaust pipes, and cooling medium distribution provided in contact with these plate-like thermoelectric modules A rectangular cooling pipe for
An exhaust heat energy recovery apparatus having a structure in which the rectangular exhaust pipe and the plate-shaped thermoelectric module are sandwiched between the rectangular cooling pipes.   The exhaust heat energy recovery apparatus according to claim 1, wherein the rectangular cooling pipes are fastened by a fastening member.   3. The exhaust heat according to claim 2, wherein the rectangular exhaust pipe, the plate-like thermoelectric module, and the rectangular cooling pipe are mechanically tightened using three or more rods provided with screws. Energy recovery device.

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