JP2016143677A - Thermoelectric power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoelectric power generation device that can be enhanced in heat energy recovery rate of high temperature fluid to enhance the power generation efficiency.SOLUTION: A thermoelectric power generation device 10 includes a recovery part 31 for recovering heat of high temperature fluid flowing at the downstream side of a branch part 13a out of a high temperature flow passage 13. Accordingly, heat energy of exhaust gas flowing in the high temperature flow passage 13 can be recovered by the recovery part 31. A thermoelectric element 12 can generate electric power by using the recovered heat. Accordingly, not only the heat energy of the high temperature fluid flowing in a branch flow path 24, but also the heat energy flowing in the high temperature flow passage 13 can be used for power generation.SELECTED DRAWING: Figure 1

Description

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

  A conventional thermoelectric power generation apparatus uses a thermoelectric element to generate power by using a temperature difference between exhaust gas and cooling water, using exhaust gas from the internal combustion engine as a high temperature side heat source and cooling water from the internal combustion engine as a low temperature side heat source. Therefore, the heat energy of exhaust gas that is discharged to the atmosphere and is wasted can be used as electric energy.

  When the accelerator opening is greater than or equal to a predetermined value, the thermoelectric generator is connected to the thermoelectric element by driving the flow rate adjustment valve in the valve closing direction in order to prevent the thermoelectric element from being damaged by high temperature exhaust gas. The exhaust gas flow rate passing through the heat exchanger is adjusted, and the exhaust gas is allowed to pass through another flow path. Thus, the amount of heat passing through the thermoelectric element is set to a predetermined value or less (see, for example, Patent Document 1).

JP 2014-66236 A

  In the technique described in Patent Document 1 described above, since the exhaust gas is passed through a separate flow path without passing the high temperature exhaust gas through the heat exchanger connected to the thermoelectric element, the thermal energy of the exhaust gas is effectively used. Have not been recovered. Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a thermoelectric power generation apparatus that can improve the power generation efficiency by improving the heat energy recovery rate of the high-temperature fluid. .

  The present invention employs the following technical means in order to achieve the aforementioned object.

  The present invention branches from a branch part (13a) provided in the high-temperature channel (13), and a branch channel (24) through which a high-temperature fluid flows, and a high-temperature fluid that flows downstream of the branch unit in the high-temperature channel. And a heat recovery part (31, 32) for recovering heat, wherein the heat recovered by the recovery part is transmitted to the end of the thermoelectric element on the branch flow path side and used for power generation of the thermoelectric element. It is a thermoelectric generator.

  According to the present invention as described above, the recovery unit recovers the heat of the high-temperature fluid flowing in the downstream side of the branching portion of the high-temperature flow path, so that the recovery unit recovers the thermal energy of the high-temperature fluid flowing in the high-temperature flow path be able to. And the thermoelectric element can generate electric power using the recovered heat. Therefore, not only the thermal energy of the high-temperature fluid flowing in the branch flow path (24) but also the thermal energy flowing in the downstream side (31) of the branch portion in the high-temperature flow path can be used for power generation. In order to use the heat recovered by the recovery unit for power generation of the thermoelectric element, it is necessary to transfer the recovered heat to the end of the thermoelectric element on the branch flow path side. Therefore, unlike the high-temperature fluid flowing through the branch channel, the heat recovered by the recovery unit is indirectly transmitted to the thermoelectric element. Therefore, it can suppress that a thermoelectric element becomes high temperature too much with the heat | fever collect | recovered by the collection | recovery part. Thereby, the recovery rate of the thermal energy of the high-temperature fluid can be improved, and the power generation efficiency can be improved.

  In addition, the code | symbol in the bracket | parenthesis of each above-mentioned means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

FIG. 2 is a diagram illustrating a piping relationship between a thermoelectric generator 10 and an engine 11. It is sectional drawing which expands and shows the thermoelectric generator 10 with the branch on-off valve 26 closed. It is sectional drawing which expands and shows the thermoelectric generator 10 with the branch on-off valve 26 open. It is a graph which shows an example of the temperature transition of waste gas. It is a graph which shows an example of transition of electric power generation amount. It is sectional drawing which expands and shows the thermoelectric generator 10 of 2nd Embodiment.

  Hereinafter, a plurality of embodiments for carrying out the present invention will be described with reference to the drawings. In some embodiments, portions corresponding to the matters described in the preceding embodiments may be given the same reference numerals, or one letter may be added to the preceding reference numerals, and overlapping descriptions may be omitted. In addition, when a part of the configuration is described in each embodiment, the other parts of the configuration are the same as those of the embodiment described in advance. In addition to the combination of parts specifically described in each embodiment, the embodiments may be partially combined as long as the combination does not hinder the combination.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. The thermoelectric generator 10 of the first embodiment is applied to a vehicle having a water-cooled engine 11. The thermoelectric power generation apparatus 10 includes a thermoelectric element 12 and generates power based on a temperature difference between exhaust gas from the engine 11 and cooling water from the engine 11.

  An engine 11 that is an internal combustion engine is provided with an intake pipe (not shown) for sucking combustion air and an exhaust pipe 13 for discharging exhaust gas after combustion. A throttle valve whose opening is variable according to the amount of depression of an accelerator pedal provided in the vehicle is provided in the intake pipe.

  The engine 11 is optimally controlled by an engine control device (not shown). Specifically, an engine speed signal, a throttle valve opening signal, a vehicle speed signal, and the like are input to the engine control device. The engine control device stores in advance a control map in which fuel injection amounts are associated with the engine speed signal and the throttle valve opening signal, and fuel required at a predetermined timing on the intake pipe side based on the control map. Is injected. The engine control device is connected to the control device 10a of the thermoelectric generator 10 so as to be able to exchange signals with each other.

  The engine 11 is provided with an engine coolant circuit 14. The engine cooling water circuit 14 is a circuit in which the cooling water in the engine 11 is circulated from the cooling water outlet portion 16 through the radiator 17 to the cooling water inlet portion 18 by the water pump 15 to cool the engine 11. . Here, the water pump 15 is an engine-driven pump that operates by receiving the driving force of the engine 11. And the cooling water is cooled by the heat radiation of the radiator 17, and the operating temperature of the engine 11 is appropriately controlled.

  The engine coolant circuit 14 is provided with a bypass passage 19 that bypasses the radiator 17 and a thermostat 20 that adjusts the coolant flow rate to the radiator 17 side or the bypass passage 19 side. When the cooling water temperature is equal to or lower than the first predetermined temperature (for example, 85 ° C.), the thermostat 20 closes the radiator 17 side, and the cooling water flows through the bypass channel 19 side, thereby preventing the cooling water from being overcooled. This corresponds to a case where the cooling water is not sufficiently heated (for example, at a low temperature start) just after the engine is started, and warming up of the engine 11 is promoted. Further, the thermostat 20 starts to open the radiator 17 side when the warm-up of the engine 11 is finished and the coolant temperature exceeds the first predetermined temperature, and the bypass channel 19 side is opened above the second predetermined temperature (for example, 90 ° C.). Closed and the radiator 17 side is fully open.

  The engine coolant circuit 14 is provided with a heater hot water circuit 22 in which a heater core 21 is disposed in parallel with the radiator 17 to form the engine coolant circuit 14. The heater core 21 is a heat exchanger for a heating device that heats air for air conditioning using cooling water (hot water) as a heat source.

  The thermoelectric generator 10 uses exhaust gas after combustion of the engine 11 and cooling water of the engine cooling water circuit 14 and includes a thermoelectric generator 23 and a control device 10a. In the thermoelectric generator 23, the branch flow path 24 and the engine inlet-side flow path 25 are provided in the thermoelectric element 12 that generates power using the Seebeck effect.

  The branch flow path 24 is a flow path formed so as to branch from the branch portion 13a of the exhaust pipe 13 of the engine 11 and merge with the exhaust pipe 13 again, and allows a part of the exhaust gas to flow therethrough. The branch flow path 24 is brought into contact with one side surface of the thermoelectric element 12 so that the exhaust gas becomes a high temperature side heat source of the thermoelectric element 12.

  A branch opening / closing valve 26 for opening and closing the branch channel 24 is provided on the downstream side of the exhaust gas with respect to the thermoelectric element 12 in the branch channel 24. The branch opening / closing valve 26 is a flow rate adjusting means for adjusting the flow rate flowing from the branching portion 13 a to the branch flow path 24.

  On the other hand, the engine inlet-side flow path 25 is a flow path that is closer to the engine 11 than the bypass flow path 19, and here is a flow that is downstream of the radiator 17 and that connects the thermostat 20 and the cooling water inlet 18. The road. The engine inlet side flow path 25 is brought into contact with the other side surface of the thermoelectric element 12. That is, the cooling water flowing through the thermostat 20 from the bypass channel 19 or the cooling water passing through the radiator 17 and flowing through the thermostat 20 is supplied to the thermoelectric element 12 side so that this cooling water becomes a low temperature side heat source of the thermoelectric element 12. I have to.

  The control device 10a stores in advance a shaft torque map, a cooling loss heat amount map of the engine 11, a water flow rate map of the engine 11, a reference heat release amount map of the radiator 17, an opening degree map of the branch on-off valve 26, and various arithmetic expressions. Yes. And the control apparatus 10a controls the opening degree of the branch on-off valve 26 based on these maps and arithmetic expressions.

  The shaft torque map is obtained by associating the fuel injection amount obtained from the engine control device with the shaft torque in advance, and is used for calculating the shaft torque when the engine 11 is operated. The shaft output is calculated from the shaft torque and the engine speed obtained from the engine control device.

  The cooling loss heat quantity map is obtained by previously relating the engine speed and the cooling loss heat quantity of the engine 11 with the shaft output as a parameter (here, no-load full load), and calculating the cooling loss heat quantity when the engine 11 is operated. Used to do. The cooling loss heat amount is obtained by multiplying the total combustion heat amount of the fuel in the engine 11 by the cooling loss, and is a heat amount radiated by the radiator 17.

  The water flow map shows the water pump 15 characteristics using the engine speed as a parameter, and the water resistance characteristics including the engine cooling water circuit 14 and the heater hot water circuit 22. Used to calculate water flow rate. And the radiator water flow volume which distribute | circulates the radiator 17 is calculated from the engine water flow volume obtained from the water flow map.

  The reference heat release map is obtained by associating the front wind speed of air flowing into the front surface of the core of the radiator 17 and the reference heat release amount of the radiator 17 in advance with the radiator 17 water flow rate as a parameter. Used to calculate the reference heat release. The opening degree map associates the exhaust heat radiation amount with the opening degree of the branch opening / closing valve 26 in advance.

  Next, the operation based on the above configuration will be described. In the operation of the engine 11, combustion air is sucked from the suction pipe according to the opening of the throttle valve, and mixed with fuel injected from an injector (not shown) and burned. The exhaust gas after combustion is purified by a catalyst (not shown) and discharged from the exhaust pipe 13 to the atmosphere. Further, by the operation of the water pump 15, the coolant circulates through the engine coolant circuit 14 and the heater warm water circuit 22.

  At the time of low temperature start when the temperature of the cooling water is equal to or lower than the first predetermined temperature, the thermostat 20 closes the radiator 17 side, and the cooling water circulates through the engine 11 through the bypass passage 19 and the engine inlet side passage 25, A part of the cooling water circulates in the heater hot water circuit 22. The control device 10a reduces the opening of the branch opening / closing valve 26 (fully closes it) and generates power by the thermoelectric element 12.

  When the engine 11 has been warmed up and the temperature of the cooling water exceeds the first predetermined temperature, the thermostat 20 opens the radiator 17 side, and the cooling water passes through the radiator 17 and the engine inlet side flow path 25 and the engine 11. Circulate. A part of the cooling water circulates in the heater hot water circuit 22. The control device 10a adjusts the opening degree of the branch opening / closing valve 26 based on each map.

  Since the cooling water flowing through the engine inlet side flow path 25 is used as the low temperature side heat source of the thermoelectric element 12, the cooling water flowing through the bypass flow path 19 is supplied to the thermoelectric element 12 when the engine 11 is started at a low temperature. it can. Accordingly, the cooling by the radiator 17 can be prevented. Further, the temperature can be raised by absorbing heat from the exhaust gas, and the warm-up performance of the engine 11 can be improved. Therefore, the friction loss can be reduced and the fuel efficiency performance of the engine 11 can be improved. In addition, the heating capacity of the heater core 21 can be improved.

  In addition, when the engine 11 is warmed up, the cooling water flows through the radiator 17 by the operation of the thermostat 20, and the cooling water whose temperature has decreased can be used as a low-temperature heat source. The amount of power generation can be increased by increasing the temperature difference.

  And since the operation load which the original generator (alternator) requires in the engine 11 by the electric power generation of the thermoelectric element 12 can be reduced, the fuel consumption of the engine 11 can be improved.

  Next, a specific configuration of the thermoelectric generator 10 will be described with reference to FIGS. 2 and 3. Hereinafter, in order to facilitate understanding, the exhaust pipe 13 may be referred to as a high temperature flow path 13 and the engine inlet side flow path 25 may be referred to as a low temperature flow path 25. The branch channel 24 branches from the high temperature channel 13 at the branch part 13a as described above. As shown in FIG. 2, a plurality of thermoelectric elements 12 are arranged between the branch channel 24 and the low temperature channel 25 along the flow direction of the exhaust gas. As shown in FIG. 2, the thermoelectric elements 12 are arranged on the heat transfer surface at intervals.

  The low temperature channel 25 intersects the inside of the branch channel 24 in a direction orthogonal to the flow direction of the exhaust gas. Therefore, the cooling water flows in the low-temperature channel 25 in a direction perpendicular to the paper surface of FIG. 2, and the flow direction of the exhaust gas and the flow direction of the cooling water are orthogonal to each other.

  In the thermoelectric element 12, the heat amount of the high temperature fluid is transmitted to the end portion on the branch flow path 24 side, and the heat amount is transmitted from the end portion on the low temperature flow path 25 side to the low temperature fluid. The thermoelectric element 12 generates electric power by a temperature difference between the exhaust gas that is a high-temperature fluid and the cooling water that is a low-temperature fluid. The thermoelectric element 12 is made of, for example, half-Heusler, bismuth tellurium, or magnesium silicite.

  The branch flow path 24 is provided with a fin 30 as a promoting portion that promotes heat transfer to the thermoelectric element 12, and the fin 30 is configured in a corrugated fin, an offset fin, or a monolith shape. The fins 30 promote heat transfer from the high-temperature channel 13 to the thermoelectric element 12. The fins 30 are made of a material excellent in heat conduction, for example, stainless steel.

  Further, a recovery unit 31 that recovers the heat of the exhaust gas is provided between the branch portion 13a and the junction portion 13b that joins the branch channel 24 in the high-temperature channel 13. The recovery unit 31 is configured in a corrugated fin, an offset fin, and a monolith shape designed to have a pressure loss smaller than that of the fin 30 and stores heat by exchanging heat with the exhaust gas. Accordingly, the recovery unit 31 is provided inside the high-temperature channel 13 and exchanges heat with the exhaust gas that passes therethrough.

  The partition wall 32 that divides the branch channel 24 and the high-temperature channel 13 also functions as a heat storage unit having a heat storage material 33 inside. Accordingly, the partition wall 32 constitutes a pipe formed by the high temperature channel 13 and collects heat of the exhaust gas flowing through the high temperature channel 13. The partition wall 32 is thermally joined to the recovery unit 31, and the heat recovered by the recovery unit 31 is transmitted to the partition wall 32. The heat transmitted to the partition wall 32 is stored in the heat storage unit.

  Further, the heat capacity of the partition walls 32 is configured to be larger than the heat capacity of the fins 30. For example, the collection unit 31 is configured to have a larger plate thickness than the fins 30 and to reduce the exhaust gas passage resistance.

  The heat radiation temperature of the heat storage material 33 is preferably in a temperature range where the power generation efficiency of the thermoelectric element 12 is high. Therefore, it is preferable that the heat storage material 33 dissipates heat in a temperature range where the heat dissipation temperature is high in the power generation efficiency of the thermoelectric element 12. Moreover, it is preferable that the heat storage material 33 has a heat radiation temperature at which the temperature of the thermoelectric element 12 is equal to or lower than the heat resistant temperature, or is equal to or lower than the heat resistant temperature of the fin 30. For example, the heat storage material 33 is selected so that the heat radiation temperature is lower of the temperature at which the temperature of the thermoelectric element 12 is equal to or lower than the heat resistance temperature and the heat resistance temperature of the fins 30.

Various materials can be used as the heat storage material 33. As the heat storage material 33, for example, a sensible heat storage material such as a stainless steel plate and a ceramic plate, a latent heat storage material such as a low melting point metal, and a chemical heat storage material such as metal oxide and hydrate can be used. Examples of the low melting point metal include aluminum, aluminum-silica composite material, LiCl-KCl, and solder. The metal oxide is, for example, CaO and MgO, hydrates, for example CaCl2-6H ₂ O.

The heat storage material 33 may have a melting point (heat radiation temperature) of 400 ° C. (673 K) to 600 ° C. (873 K), for example, and may be a material capable of high-temperature heat storage with large latent heat. For example, as the heat storage material 33 that has a large heat storage density and facilitates downsizing of the apparatus, a mixed salt of lithium hydroxide-lithium fluoride (LiOH-LiF) and a mixed salt of lithium hydroxide-lithium carbonate (LiOH-Li2CO ₃ ) , Lithium chloride-lithium fluoride mixed salt (LiCl-LiF), lithium hydride-sodium chloride (LiH-NaCl), lithium hydroxide single component salt (LiOH), and the like.

As an inexpensive heat storage material 33, a mixed salt of sodium chloride-magnesium chloride (NaCl-MgCl2), a mixed salt of lithium fluoride-sodium fluoride-sodium chloride (LiF-NaF-NaCl), and a mixed salt of sodium chloride-calcium chloride Salt (NaCl—CaCl ₂ ), mixed salt of sodium chloride and potassium chloride (NaCl—KCl), and the like.

Further, as the heat storage material 33 having a large thermal conductivity, a single metal such as zinc (Zn), an aluminum-silicon alloy (Al-Si), an aluminum-copper-magnesium-zinc alloy (Al-Cu-Mg-Zn), or the like There is. What was illustrated above can adjust melting | fusing point by using eutectic salt. A material containing a chemical heat storage material such as a metal salt (NaCl, MgCl ₂ ), a hydrated complex, a latent heat storage material such as an organic compound, or an inorganic compound (CaO, silica gel, etc.) can also be used.

Further, as the heat storage material 33, NaF—SnF ₂ (melting temperature 253 ° C.), NaOH—NaNO ₂ (melting temperature 237 ° C.), NaOH—NaNO ₃ (melting temperature 257 ° C.), LiNO ₃ (melting temperature 264 ° C.), NaOH— NaNO ₂ (melting temperature 237 ° C.), SnF ₂ (melting temperature 213 ° C.), NaNO ₂ (melting temperature 282 ° C.), or the like may be used.

As the heat storage material 33, LiOH (melting temperature 462 ° C.), NaCl—MgCl ₂ (melting temperature 450 ° C.), KF—LiF—MgF ₂ —NaF (weight composition 55: 27: 6: 12, melting temperature 449 ° C.), KF Fluoride eutectic salts such as —LiF—NaF (weight composition 59:29:12, melting temperature 454 ° C.) may be used.

  As shown in FIG. 2, when the branch flow path 24 is closed by the branch opening / closing valve 26, the exhaust gas flows through the high temperature flow path 13 without flowing through the branch flow path 24. The exhaust gas flowing through the high-temperature channel 13 exchanges heat with the recovery unit 31 and the partition wall 32, and heat is recovered by the recovery unit 31 and the partition wall 32. In other words, the collection unit 31 and the partition wall 32 are heated by the exhaust gas to store heat.

  As shown in FIG. 3, when the branch flow path 24 is opened by the branch opening / closing valve 26, the exhaust gas flows through the branch flow path 24 without flowing through the high temperature flow path 13. The exhaust gas flowing through the branch flow path 24 recovers heat by the fins 30 and heats one end of the thermoelectric element 12. Then, the thermoelectric element 12 generates heat due to a temperature difference between the branch channel 24 and the low temperature channel 25. Even in the state shown in FIG. 2, the recovered heat is transferred to the thermoelectric element 12 by the fins 30. Electricity is also generated by the recovered heat.

  Next, the temperature transition of exhaust gas and the transition of power generation will be described using graphs. As shown in FIG. 4, the temperature of the exhaust gas varies depending on the load of the vehicle. When the temperature of the exhaust gas is high and is in a high temperature region, if the exhaust gas flows through the branch flow path 24, the thermoelectric element 12 may become too hot and be damaged. Therefore, in the high temperature region, the branch on-off valve 26 is closed and control is performed so that the exhaust gas does not flow through the branch flow path 24.

  The amount of power generation is proportional to the exhaust gas temperature. Therefore, when the exhaust gas temperature is low as in the region indicated by the broken line in FIG. 4, the amount of power generation decreases as shown in FIG. 5 as a comparative example. Therefore, in the present embodiment, in the high temperature region, the heat of the exhaust gas flowing through the high temperature channel 13 is recovered by the recovery unit 31 and the partition wall 32. Then, as shown in FIG. 5 as an example, when the exhaust gas is at a low temperature, power is generated by the recovered heat, and a high power generation amount can be maintained even when the exhaust gas is at a low temperature.

  As described above, the thermoelectric generator 10 of the present embodiment includes the recovery unit 31 that recovers the heat of the high-temperature fluid flowing in the high-temperature flow path 13 on the downstream side of the branch part 13a. Therefore, the heat energy of the exhaust gas flowing through the high temperature channel 13 can be recovered by the recovery unit 31. And the thermoelectric element 12 can generate electric power using the recovered heat. Thus, not only the thermal energy of the high-temperature fluid flowing through the branch flow path 24 but also the thermal energy flowing through the high-temperature flow path 13 can be used for power generation. In order to use the heat recovered by the recovery unit 31 for power generation of the thermoelectric element 12, it is necessary to transmit the recovered heat to the end of the thermoelectric element 12 on the branch flow path 24 side. Therefore, unlike the high-temperature fluid flowing through the branch flow path 24, the heat recovered by the recovery unit 31 is transmitted to the thermoelectric element 12 via the partition wall 32. Therefore, the thermoelectric element 12 can be prevented from becoming excessively high due to the heat recovered by the recovery unit 31. Thereby, the recovery rate of the thermal energy of the high-temperature fluid can be improved, and the power generation efficiency can be improved.

  In other words, it can be effectively used for power generation without exhausting all of the high-temperature exhaust gas. Further, more high-temperature exhaust heat can be recovered when the engine 11 is at a high load, and more power can be generated at a low load when the power generation amount is small. Further, since the thermoelectric element 12 does not reach a high temperature, the thermoelectric element 12 can be prevented from being damaged at a high temperature. In addition, power can be generated in a region where power generation efficiency is good.

  Further, heat can be recovered by the recovery unit 31 and the partition wall 32 at the time of high-temperature exhaust heat amount, and power can be generated with a time delay by the recovered heat. That is, when the fins 30 of the branch flow path 24 become low temperature, heat is transferred from the recovery unit 31 and the partition walls 32 to the fins 30. As a result, when the branch flow path 24 becomes low temperature, the recovery part 31 and the partition wall 32 radiate heat, so that the temperature of the branch flow path 24 can be kept high.

  In the present embodiment, the recovery unit 31 is provided inside the high-temperature channel 13. As a result, the recovery unit 31 directly exchanges heat with the exhaust gas flowing through the high-temperature channel 13, so that the heat exchange rate can be improved. Therefore, more heat can be recovered by the recovery unit 31.

  Furthermore, in this embodiment, heat is also recovered by the partition wall 32 that forms the high-temperature channel 13. As a result, the member that simply forms the high-temperature channel 13 can be effectively utilized for heat recovery. Thereby, the heat capacity of the recovery unit 31 can be increased.

  In the present embodiment, the collection unit 31 is configured to have a larger heat capacity than the fins 30. Thereby, the recovery unit 31 recovers a large amount of heat, and can maintain the branch flow path 24 at a high temperature when the exhaust gas is at a low temperature.

  Furthermore, in this embodiment, the partition 32 has a heat storage part which stores the heat recovered inside. As a result, not only the high-temperature exhaust gas is transmitted to the branch flow path 24, but also heat can be temporarily stored. Thereby, the heat radiation time of the partition wall 32 can be lengthened. Therefore, it is possible to lengthen the time during which the exhaust gas is heated.

  In the present embodiment, the heat radiation temperature of the partition wall 32 is within a temperature range where the power generation efficiency of the thermoelectric element 12 is high. As a result, the power generation efficiency of the thermoelectric element 12 can be maintained at a high level. Therefore, the recovered heat can be used effectively. In addition, it is possible to prevent the thermoelectric element 12 from becoming too high due to heat radiation from the partition wall 32.

  Furthermore, in the present embodiment, the heat radiation temperature of the partition walls 32 is equal to or lower than the heat resistance temperature of the thermoelectric element 12 and is equal to or lower than the heat resistance temperature of the fins 30. As a result, the thermoelectric element 12 and the fin 30 can be prevented from being damaged by the heat radiation from the partition wall 32.

  In the present embodiment, the branch opening / closing valve 26 is provided as a flow rate adjusting means for adjusting the flow rate flowing from the branch portion 13a to the branch flow path 24. The branch opening / closing valve 26 can prevent high-temperature exhaust gas from flowing through the branch flow path 24. Further, by adjusting the opening degree of the branch opening / closing valve 26, the exhaust gas can flow through both the branch flow path 24 and the high temperature flow path 13. Accordingly, heat can be recovered by the recovery unit 31 and the partition wall 32 while generating power with the thermoelectric element 12.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. The present embodiment is characterized in that the recovery section 31 is not provided inside the high-temperature flow path 13 and that the heat storage material 332 is also provided in a portion other than the partition wall 32.

  As shown in FIG. 6, the recovery unit 31 may or may not be provided inside the high-temperature channel 13. However, a heat storage material 332 is provided inside the tube wall constituting the high-temperature flow path 13 in the same manner as the partition wall 32. Further, the heat storage material 332 is also provided inside the tube wall constituting the branch flow path 24, similarly to the partition wall 32.

  The heat storage material 332 is made of the same material as the partition wall 32. Since the heat storage material 332 is provided in the branch flow path 24, even if a high-temperature exhaust gas flows through the branch flow path 24, the heat storage material 332 stores heat, so that the branch flow path 24 is prevented from becoming high temperature. Can do. Further, when the exhaust gas in the branch flow path 24 is at a low temperature, it can be raised to an appropriate temperature by the heat radiation of the heat storage material 332 in the branch flow path 24.

  Although the recovery unit 31 is not provided inside the high temperature channel 13, the heat of the exhaust gas that passes through the high temperature channel 13 can be recovered by the partition wall 32 and the heat storage material 332 of the high temperature channel 13. As a result, the same operations and effects as those of the first embodiment can be obtained.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  The structure of the said embodiment is an illustration to the last, Comprising: The scope of the present invention is not limited to the range of these description. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  In the first embodiment described above, the downstream side of the branch flow path 24 is connected to the merging section 13b located on the downstream side of the branch section 13a of the high temperature flow path 13, but the branch flow path 24 has such a configuration. It is not limited to. The branch flow path 24 may be discharged to the atmosphere as it is by another route without joining.

  In the first embodiment described above, the low temperature flow path 25 passes through the center of the branch flow path 24. However, the present invention is not limited to such a configuration, and the low temperature flow path 25 is arranged in parallel above the branch flow path 24. It may be provided as follows.

  In the first embodiment described above, the thermoelectric element 12 generates power using exhaust gas that is a high-temperature fluid and cooling water that is a low-temperature fluid. However, the high-temperature fluid and the low-temperature fluid are not limited to exhaust gas and cooling water. For example, the high-temperature fluid may be exhaust gas other than the internal combustion engine. The low temperature fluid may introduce outside air instead of cooling water. Further, the present invention is not limited to vehicles, and may be applied to other vehicles, factories, and ordinary houses.

  In the first embodiment described above, each of the branch flow path 24 and the high temperature flow path 13 is one, but is not limited to one, and either one may be plural or both may be plural. Good.

  In the first embodiment described above, the branch opening / closing valve 26 is provided on the downstream side of the branch flow path 24, but is not limited to the downstream side. The branch opening / closing valve 26 may be provided on the upstream side of the branch flow path 24.

DESCRIPTION OF SYMBOLS 10 ... Thermoelectric power generator 10a ... Control apparatus 11 ... Engine (internal combustion engine) 12 ... Thermoelectric element 13 ... Exhaust pipe (high temperature flow path) 13a ... Branch part 24 ... Branch flow path 25 ... Engine inlet side flow path (low temperature flow path)
26 ... Branch opening / closing valve (flow rate adjusting means) 30 ... Fin (promotion part)
31 ... collection part 32 ... partition (collection part, heat storage part)
33 ... heat storage material

Claims (11)

A high-temperature channel (13) through which a high-temperature fluid flows;
A branch channel (24) branched from a branch section (13a) provided in the high-temperature channel and through which the high-temperature fluid flows;
A low-temperature flow path (25) through which a low-temperature fluid having a temperature lower than that of the high-temperature fluid flows;
A thermoelectric element provided between the branch flow path and the low temperature flow path, wherein an amount of heat of the high temperature fluid is transmitted to an end portion on the branch flow path side, and from the end portion on the low temperature flow path side to the low temperature fluid. A thermoelectric element (12) for transmitting heat and generating electricity by a temperature difference between the high temperature fluid and the low temperature fluid;
A recovery part (31, 32) for recovering heat of the high-temperature fluid flowing downstream of the branch part in the high-temperature flow path;
The heat recovered by the recovery unit is transmitted to an end of the thermoelectric element on the branch flow path side and used for power generation of the thermoelectric element.   The thermoelectric generator according to claim 1, wherein the recovery unit is provided inside the high-temperature channel.   The thermoelectric generator according to claim 1, wherein the recovery unit is provided in a pipe that forms the high-temperature channel.   The thermoelectric power generator according to any one of claims 1 to 3, further comprising a promotion portion (30) that promotes heat transfer from the branch flow path to the thermoelectric element.   The thermoelectric generator according to claim 4, wherein the recovery unit has a larger heat capacity than the promotion unit.   The thermoelectric generator according to claim 4 or 5, wherein the recovery unit has a pressure loss of the high-temperature fluid smaller than that of the promotion unit.   The thermoelectric generator according to claim 1, wherein the recovery unit includes a heat storage unit (32) that stores the recovered heat.   The thermoelectric generator according to claim 7, wherein the heat radiation temperature of the heat storage unit is within a temperature range where the power generation efficiency of the thermoelectric element is high. And further includes an accelerating portion (30) for promoting heat transfer from the branch channel to the thermoelectric element,
The thermoelectric power generator according to claim 7 or 8, wherein the heat radiation temperature of the heat storage unit is such that the temperature of the thermoelectric element is equal to or lower than a heat resistant temperature, and is equal to or lower than the heat resistant temperature of the accelerating portion.   The thermoelectric generator according to any one of claims 1 to 9, further comprising a flow rate adjusting means (26) for adjusting a flow rate flowing from the branch portion to the branch flow path. The high temperature fluid is exhaust gas from the internal combustion engine (11),
The thermoelectric power generator according to claim 1, wherein the low-temperature fluid is cooling water that cools the internal combustion engine.

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