JP6547694B2 - Thermoelectric generator - Google Patents

Description

  The disclosure in this specification relates to a thermoelectric generator that converts thermal energy into electrical energy by the Seebeck effect.

  The thermoelectric power generation device of Patent Document 1 estimates the power generation amount of the thermoelectric converter from the detected value of the vehicle speed detected by the vehicle speed sensor and the map determined in advance, and the thermoelectric power generation amount of the thermoelectric converter is smaller than the estimated power generation amount. It is determined that the converter is broken.

Japanese Patent Application Publication No. 2007-14084

  In a vehicle, exhaust gas temperature, exhaust gas flow rate, cooling water temperature, cooling water flow rate, etc. are not uniquely determined based on the vehicle speed, but are parameters that are greatly affected by, for example, running load related to acceleration, braking, etc. . For this reason, as in the device of Patent Document 1, there is room for improvement in the accuracy of the power generation amount estimated based on the vehicle speed, and failure determination using this power generation amount estimation value also has a problem in terms of its accuracy. .

  In view of such a subject, the object of the indication in this specification is to provide the thermoelectric-generation device which can aim at the precision improvement of failure determination.

  Several aspects disclosed in this specification employ different technical means from one another in order to achieve each purpose. Further, the claims and the reference numerals in the parentheses described in this section are an example showing the correspondence with the specific means described in the embodiment described later as one aspect, and the technical scope is limited. is not.

  One of the disclosed thermoelectric power generators includes a first fluid passage (27) through which the first fluid flows, and a second fluid passage which is hotter than the first fluid and through which the second fluid discharged from the engine (20) flows. (31) and a thermoelectric conversion element, the heat of the first fluid is movable to one side (10a), and the heat of the second fluid is movable to the other side (10b) And a control unit (5) capable of acquiring an open circuit voltage and an alternating current resistance for the thermoelectric generator, which generates electric power by a temperature difference between one side and the other side. The control device determines whether or not a failure occurs in the thermoelectric generator according to the detected AC resistance, when the detected open circuit voltage falls below the reference value, immediately before restarting after the engine is stopped.

  According to this thermoelectric generator, the thermoelectric generator is not warmed when the open circuit voltage detected immediately before the restart of the engine is less than the reference value. At this time, it can be determined that there is not much temperature difference between one side and the other side, and the AC resistance of the thermoelectric generator can be accurately detected. This is because when the temperature difference is large and the current value of the thermoelectric generator is large, the error of the AC resistance, which is the electrical resistance, becomes large. Since the thermoelectric generator determines whether or not a failure occurs in the thermoelectric generator based on the AC resistance detected in such a situation, the failure excluding the highly temperature-dependent parameter that can be complicatedly fluctuated according to the load Judgment can be implemented. Therefore, according to this thermoelectric power generation device, it is possible to improve the accuracy of the failure determination with respect to the prior art in which the failure determination is performed using the estimated value of the power generation amount based on the vehicle speed.

It is the outline figure which showed the relation between the thermoelectric-generation device of a 1st embodiment, cooling water, and exhaust gas. It is a control block diagram regarding the thermoelectric-generation apparatus of 1st Embodiment. In 1st Embodiment, it is a flowchart which performs a data accumulation process during engine driving | operation. In 1st Embodiment, it is a flowchart which performs failure determination processing at the time of engine restart. It is a graph which shows the open circuit voltage for every engine revolving speed memorized by storage part for failure judging processing. In 2nd Embodiment, it is a flowchart which performs failure determination processing at the time of engine restart. In 3rd Embodiment, it is a flowchart which performs failure determination processing at the time of engine restart.

  Hereinafter, a plurality of modes for carrying out the present disclosure will be described with reference to the drawings. The same referential mark may be attached | subjected to the part corresponding to the matter demonstrated by the form preceded in each form, and the overlapping description may be abbreviate | omitted. When only a part of the configuration is described in each form, the other forms described above can be applied to other parts of the configuration. Not only combinations of parts which clearly indicate that combinations are possible in each embodiment, but also combinations of embodiments even if not explicitly specified, unless any problem occurs in the combinations. It is also possible.

First Embodiment
The thermoelectric generation device 1 of the first embodiment will be described with reference to FIGS. 1 to 5. The thermoelectric power generation device 1 is a device that converts thermal energy into electric power energy by the Seebeck effect using a temperature difference between an exhaust gas as a second fluid discharged from the engine 20 and a first fluid that is lower in temperature than the exhaust gas. is there. When a temperature difference is given between the low temperature side 10a which is one side and the high temperature side 10b which is the other side in the thermoelectric generator 10 having the thermoelectric conversion element, the thermoelectric power generation device 1 produces a potential difference to generate electrons. Generate electricity using flowing phenomena. The first fluid may be any fluid capable of providing a temperature difference with the exhaust gas. In this embodiment, the case of using the cooling water of the engine 20 of a car as an example of the arbitrarily selectable low temperature fluid will be described.

  An intake pipe for sucking in combustion air and an exhaust pipe 3 for discharging exhaust gas after combustion are connected to an engine 20 which is an internal combustion engine. The intake pipe is provided with a throttle valve whose opening degree is varied in accordance with the amount of depression of an accelerator pedal provided in the vehicle. The engine 20 is controlled to an optimum operation by the engine control device 4. An engine rotation number signal, a throttle valve opening degree signal, a vehicle speed signal, and the like are input to the engine control device 4. The engine control device 4 stores in advance a control map in which the fuel injection amount is associated with the engine rotational speed signal and the throttle valve opening degree signal. The engine control device 4 controls the amount of fuel injection required at a predetermined timing on the intake pipe side based on the control map. The engine control device 4 is connected to the control device 15 of the thermoelectric power generation device 1 so as to be able to communicate with each other.

  The coolant circuit 2 is connected to the engine 20. The cooling water circuit 2 is a circuit through which cooling water in the engine 20 circulates to cool the engine 20. The cooling water is circulated by the water pump 24 from the outlet 20b through the radiator 21 to the inlet 20a. The water pump 24 is, for example, an engine driven pump that operates by receiving the driving force of the engine 20. Since the cooling water circulating through the cooling water circuit 2 is cooled by the heat radiation of the radiator 21, the operating temperature of the engine 20 can be properly controlled.

  The coolant circuit 2 is provided with a bypass passage 26 for bypassing the radiator 21 and a thermostat 22 for adjusting the flow rate of coolant to the radiator 21 side or the bypass passage 26 side. When the cooling water temperature is equal to or lower than the first predetermined temperature, the radiator 21 is closed by the thermostat 22 and the cooling water flows through the bypass passage 26 side, so that the overcooling of the cooling water can be prevented. This corresponds to, for example, the case where the temperature of the cooling water is not sufficiently raised as immediately after the start of the engine 20, and the warm-up of the engine 20 can be promoted. Further, when the warming up of the engine 20 is completed and the coolant temperature exceeds the first predetermined temperature, the thermostat 22 starts to open the radiator 21 side, closes the bypass passage 26 at the second predetermined temperature or more, and Fully open. The cooling water circuit 2 is provided with a heater core 23 and a heater hot water circuit 25 forming a part of the cooling water circuit 2 in parallel to the radiator 21. The heater core 23 is a heat exchanger for a heating device that heats air for air conditioning using cooling water as a heat source.

  The thermoelectric generator 1 includes a thermoelectric generator 10 and a control device 5 that controls the operation of the thermoelectric generator 10. The thermoelectric generator 10 is configured by arranging a branch passage 31 which is a second fluid passage and a circulation passage 27 which is a first fluid passage with respect to a thermoelectric conversion element which generates electric power using the Seebeck effect. It is done. The branch passage 31 constitutes a passage which is branched from the exhaust pipe 3 of the engine 20 and joined again to the exhaust pipe 3 so that part of exhaust gas is branched. The branch passage 31 contacts the thermoelectric conversion element or the high temperature side 10 b which is the other side surface of the thermoelectric generator 10, and the exhaust gas serves as the high temperature side heat source of the thermoelectric conversion element. On the upstream side of the exhaust gas with respect to the thermoelectric conversion element of the branch passage 31, an on-off valve 30 for opening and closing the branch passage 31 is provided.

  The circulation passage 27 is a passage that is closer to the engine 20 than the bypass passage 26 and is a passage that connects the thermostat 22 and the inlet 20 a on the downstream side of the radiator 21. The circulation passage 27 is in contact with the thermoelectric conversion element or the low temperature side 10 a which is one side of the thermoelectric generator 10. The coolant flowing from the bypass passage 26 through the thermostat 22 or the coolant passing through the radiator 21 and flowing through the thermostat 22 is supplied to the thermoelectric conversion element side, and this coolant becomes the low temperature side heat source of the thermoelectric conversion element.

  The control device 5 includes a device such as a microcomputer operating according to a program as a main hardware element. As illustrated in FIG. 2, the control device 5 includes an interface unit 50 (hereinafter, also referred to as an I / F unit 50) to which various devices and various sensors are connected, an arithmetic processing unit 51, and a storage unit 52. Equipped with The arithmetic processing unit 51 performs determination processing and arithmetic processing according to a predetermined program using the information acquired from various sensors and various measuring devices through the I / F unit 50 and the various data stored in the storage unit 52.

  The storage unit 52 includes a writable storage medium, and temporarily stores information based on the signals output from the respective detectors in the storage medium. The storage unit 52 is a non-transitory tangible storage media. The arithmetic processing unit 51 is a determination unit in the control device 5. The I / F unit 50 operates various devices based on the determination result by the calculation processing unit 51 and the calculation result. Therefore, the I / F unit 50 is an input unit and a control output unit in the control device 5. Further, the control device 5 may be integrated with the engine control device 4 and may constitute a part of the engine control device 4.

  The I / F unit 50 acquires an engine speed, engine load information, and the like from the engine control device 4 as an engine information signal. The engine load information is, for example, a torque value of the engine 20. The rotational speed detector 40 is a sensor that detects the rotational speed of the engine 20. The arithmetic processing unit 51 performs arithmetic processing on various engine information signals and the like from the engine control device 7 in accordance with a preset program. The control device 5 controls the on-off valve 30 and the like based on the calculation result by the calculation processing unit 51. The control device 5 stores in advance the axial torque map, the cooling loss heat amount map of the engine 20, the water flow rate map of the engine 20, the reference heat release amount map of the radiator 21, the opening degree map of the on-off valve 30, and various arithmetic expressions. . The control device 5 controls the opening degree of the on-off valve 30 based on these maps and arithmetic expressions.

  The arithmetic processing unit 51 performs arithmetic processing related to failure determination of the thermoelectric generator 10 in accordance with various information detected by the rotational speed detector 40, the voltage detector 41, the resistance detector 42, and the like and a predetermined program. The voltage detector 41 detects an open circuit voltage in the thermoelectric generator 10 and outputs the open circuit voltage to the control device 5. The open circuit voltage is also referred to as an open circuit voltage. The open circuit voltage is data indicating the heat exchange performance of the thermoelectric generator 10, and is data that can not be accurately detected when the temperature difference between the low temperature side 10a and the high temperature side 10b is small. The control device 5 is configured to acquire data from the voltage detector 41 according to the temperature difference between the low temperature side 10 a and the high temperature side 10 b. For example, the controller 5 acquires data from the voltage detector 41 when the temperature difference between the low temperature side 10 a and the high temperature side 10 b is large.

  The resistance detector 42 detects an AC resistance of the thermoelectric generator 10 and outputs the same to the control device 5. The alternating current resistance is data indicating the electrical resistance of the thermoelectric generator 10, and is data that can not be accurately detected when the temperature difference between the low temperature side 10a and the high temperature side 10b is large. The control device 5 is configured to acquire data from the resistance detector 42 when the temperature difference between the low temperature side 10 a and the high temperature side 10 b is small.

  The I / F unit 50 operates devices such as the on-off valve 30 based on the calculation result by the calculation processing unit 51. The I / F unit 50 is connected to a terminal device serving as a user interface, such as a control panel or a portable terminal. The user can confirm the current driving state output from the I / F unit 50 through the display unit 53 of the control panel and the display screen of the terminal device or the like. In addition, failure information of the thermoelectric generator 10 based on the failure determination process is displayed on the display screen of the display unit 53 or the like.

  Next, an example of the failure determination process performed by the thermoelectric power generation system 1 will be described with reference to FIGS. This failure determination process is a process of determining at the time of restart of the engine 20 whether or not there is a failure that the thermoelectric generator 10 can not generate power normally. The flowchart shown in FIG. 3 shows the process executed by the control device 5 while the engine 20 is in operation. In the flowchart shown in FIG. 3, during operation of the engine 20, processing is performed to store the open circuit voltage Voc detected for each engine rotational speed as a performance value. The flowchart shown in FIG. 4 shows the process executed by the control device 5 when the engine 20 is stopped and then restarted.

  As shown in FIG. 3, the arithmetic processing unit 51, which is a determination unit, determines whether or not the engine 20 is operating in step S100. Step S100 is repeated until the engine 20 is operated. When the engine 20 is in operation, a process of setting the maximum value Vocmax (Ne) of the open circuit voltage to zero and storing the same in the storage unit 52 is performed in step S110. Ne represents the engine rotational speed at the time of open circuit detection. In step S120, the control device 5 detects the open circuit voltage Voc by the voltage detector 41 during engine operation, and acquires the open circuit voltage Voc and the engine rotational speed as a set in association with the engine rotational speed at that time.

  In step S130, it is determined whether Voc (Ne) acquired in step S120 is larger than Vocmax (Ne) stored in the storage unit 52. Since Voc (Ne) acquired first after operation of the engine 20 is larger than zero, the arithmetic processing unit 51 determines YES in step S130, and sets Voc (Ne) to Vocmax (Ne) in step S140. Execute the process The storage unit 52 stores a new Vocmax (Ne). Next, in step S150, it is determined whether the ignition switch is in the off state, and if it is in the off state, the present flowchart is ended.

  If the ignition switch is not in the off state and the engine 20 is in continuous operation, the process returns to step S120, and the control device 5 acquires the detected open circuit voltage Voc in association with the engine rotation speed. If it is determined in step S130 that Voc (Ne) acquired in step S120 is equal to or less than Vocmax (Ne) of the rotational speed of the same level stored in storage unit 52, the process returns to step S120 to detect Voc and rotate. Get speed and Voc as a set. As described above, a new Voc (Ne) during engine operation is continuously acquired in step S120 without rewriting the acquired Voc (Ne) to Vocmax (Ne) in step S140 until it is determined as YES in step S130. If it is determined in step S130 that Voc (Ne) acquired in step S120 is larger than Vocmax (Ne) at the engine rotational speed of the same level, Vocmax (Ne) is updated in step S140 and stored in storage unit 52. Execute the process to

  The actual value of Voc is stored in the storage unit 52 as an open circuit voltage value for each same engine rotational speed, as in the graph illustrated in FIG. 5, for example. The actual value of Voc may be configured to be stored in the storage unit 52 as an open circuit voltage value for each same engine target rotational speed or as an open circuit voltage value for each same vehicle speed.

  When the ignition switch is turned off, YES is determined in step S150 of FIG. 3 and the flowchart of FIG. 3 is ended, and data accumulation of the open circuit voltage Voc during engine operation is ended. Next, when the engine 20 is restarted, the control device 5 starts the process shown in the flowchart of FIG. 4. When the control device 5 acquires a signal for restarting the engine 20 from the engine control device 4, the control device 5 executes the process according to the flowchart of FIG.

  As shown in FIG. 4, immediately before the restart of the engine 20, that is, after the stop of the engine 20 and before the next operation of the engine 20 starts, the processes of step S200 and step S220 are performed. This is because when the thermoelectric generator 10 is warmed by the exhaust gas and the temperature difference between the low temperature side 10a and the high temperature side 10b increases, the AC resistance of the thermoelectric generator 10 can not be accurately detected. The control device 5 can increase the accuracy of the failure determination by using the AC resistance value in a state not affected by the temperature for the failure determination.

  First, in step S200, the arithmetic processing unit 51 determines whether the open circuit voltage Voc (0) acquired before starting is smaller than a predetermined reference value Vocmin. If Voc (0) immediately before the start of the engine is a value equal to or greater than the reference value, the thermoelectric conversion element is in a warmed state, and a temperature difference between the low temperature side 10a and the high temperature side 10b of the thermoelectric conversion element is generated. Therefore, the abnormal AC resistance value can not be accurately detected, and accurate failure determination can not be performed. The reference value Vocmin is set to a value capable of detecting a determinable state excluding such a state, and is stored in the control device 5 in advance. If it is determined NO in step S200, the thermoelectric conversion element is in a warm state and failure determination is impossible, so determination is made as to whether or not a failure has occurred, and the present flowchart ends.

  If YES in step S200, the arithmetic processing unit 51 determines in step S210 whether or not the acquired AC resistance Rac is larger than a predetermined determination value Rac0, which is detected by the resistance detector 42 before starting. Do. The determination value Rac0 is a value that is set to maintain that the generation capacity required of the thermoelectric generator 10 as a product can be output. For example, the determination value Rac0 is a value that is set based on the fact that the required power generation capacity can not be exhibited when Rac exceeds this value. If NO is determined in step S210, it is possible to determine that the thermoelectric generator 10 can output the necessary power generation capacity and is normal, and the present flowchart ends.

  If YES in step S210, operation processing unit 51 next determines whether Voc0 (Ne) detected after start of engine 20 is larger than Vocmax (Ne) stored in storage unit 52 in step S220. judge. Vocmax (Ne) is the maximum value of Voc stored in the storage unit 52 for each actual rotational speed. For example, Vocmax (Ne) is the largest value of Voc in each column among data arranged in a line in the vertical direction in the graph of FIG. 5. In the graph of FIG. 5, a plurality of data arranged in a line in the vertical direction are actual values of the open circuit voltage Voc detected for rotational speeds of the same level. Therefore, Voc0 in the determination process of step S220 is determined to be YES if it is larger than Vocmax (Ne) for all rotational speeds shown in FIG. 5, and it is determined to be NO otherwise. As described above, in step S220, is whether the open circuit voltage value detected at the time of restart of the engine 20 exceeds the maximum value of the open circuit voltage at all actual rotational speeds among the stored actual values of the open circuit voltage? It is determined whether or not.

  If it determines with NO by step S220, it will determine with this embodiment that it is normal, and will complete | finish this flowchart. If it determines with YES by step S220, the arithmetic processing part 51 will determine whether the estimated value of the electric power generation capacity estimated from the actual value of an open circuit voltage is lower than an allowance level by step S230. If it determines with NO by step S230, it will not determine with the thermoelectric generator 10 having a failure, and this flowchart will be complete | finished. If YES is determined in step S230, the thermoelectric generator 10 is in a state in which it can not exhibit a desired power generation capacity, so processing of failure occurrence is executed in step S240, and the present flowchart is ended. For example, the control device 5 performs a process of notifying the user that a failure has occurred is displayed on the display unit 53 or notified by voice or the like.

  In step S230, it is determined whether the value obtained by dividing the estimated value Pteg of the power generation capacity by the target value Pteg0 of the power generation capacity is smaller than a predetermined judgment value Ptegf. The judgment value Ptegf is set to a value corresponding to, for example, the case where the power generation performance of the thermoelectric generator 10 decreases from the 100% capacity state beyond the allowable level.

  Pteg / Pteg0 is calculated by the following equation.

Pteg / Pteg0 = (Vocmax / Voc0) ² / (Rac / Rac0)
Further, PTEG is represented by ^Voc 2 / Rac, Pteg0 is represented by Voc0 ² / Rac0.

  Next, the effect which the thermoelectric-generation apparatus 1 of 1st Embodiment brings about is demonstrated. The thermoelectric generation device 1 can obtain the circulation passage 27 through which the cooling water flows, the branch passage 31 through which the exhaust gas discharged from the engine 20 flows, the thermoelectric generator 10, and the open circuit voltage and the AC resistance of the thermoelectric generator 10. And the control device 5. The thermoelectric generator 10 has a thermoelectric conversion element, is capable of transferring the heat of the cooling water to the low temperature side 10a, is provided on the high temperature side 10b so that the heat of exhaust gas can be transferred, Power is generated by the temperature difference between 10a and the high temperature side 10b. When the open circuit voltage detected falls below the reference value immediately before the engine 20 is stopped and then restarted, the control device 5 determines whether or not the failure of the thermoelectric generator 10 has occurred according to the detected AC resistance. .

  According to the thermoelectric generator 1, when the open circuit voltage detected immediately before the restart after the engine 20 is stopped is lower than the reference value, the thermoelectric generator 10 is not in a warm state. It can be determined that this state is a state where there is not much temperature difference between the low temperature side 10a and the high temperature side 10b, and the AC resistance of the thermoelectric generator 10 can be detected accurately. This utilizes the property that when the temperature difference is large and the current value of the thermoelectric generator 10 is large, the error of the AC resistance, which is the electrical resistance, becomes large. The thermoelectric generator 1 determines whether or not a failure occurs in the thermoelectric generator 10 according to the AC resistance detected in such a situation. For this reason, failure determination of the thermoelectric generator 10 can be carried out excluding parameters having a high temperature dependence that can vary complicatedly depending on the load. According to this thermoelectric power generation device 1, the accuracy of the failure determination can be sufficiently improved as compared with the technique of performing the failure determination using the estimated value of the power generation amount based on the conventional vehicle speed.

  In control device 5, the detected open circuit voltage is lower than the reference value immediately before engine 20 is restarted, the detected AC resistance exceeds the determination value, and the open circuit voltage detected after engine 20 is restarted is a record of the open circuit voltage If the value is exceeded, a determination regarding the power generation capacity is further made. The control device 5 determines that a failure has occurred when the estimated value of the power generation capacity obtained using the detected AC resistance and the actual value of the open circuit voltage is lower than the allowable level.

  According to this failure judgment, in addition to the judgment processing excluding the parameter highly dependent on temperature and the judgment processing comparing the heat exchange performance after restart with respect to the past heat exchange performance, the estimated power generation capacity is further permitted It is possible to provide a failure determination in which it is determined whether or not a level is secured. Therefore, the accuracy of the failure determination can be significantly improved as compared with the conventional technology in which the failure determination is performed using the estimated value of the power generation amount based on the vehicle speed.

Second Embodiment
The failure determination processing at engine restart in the second embodiment will be described with reference to the flowchart of FIG. The steps given the same reference numerals in FIG. 6 as in FIG. 4 of the first embodiment are the same as in the first embodiment. The configurations, processes, operations, and effects not particularly described in the second embodiment are the same as those in the first embodiment, and only differences from the first embodiment will be described below.

  The failure determination process at engine restart of the second embodiment executes the process of occurrence of failure at S240 when both steps S200 and S210 are determined as YES with respect to the failure determination process of the first embodiment. Is different. According to the failure determination process of the second embodiment, accurate AC resistance can be detected in a situation where there is not much temperature difference between the low temperature side 10a and the high temperature side 10b, so that the thermoelectric power generation excluding the parameters highly dependent on temperature It is possible to carry out the failure judgment of the According to the failure determination process, the accuracy of the failure determination can be sufficiently improved as compared to the conventional technology of performing the failure determination using the estimated value of the power generation amount based on the vehicle speed.

Third Embodiment
The failure determination processing at engine restart in the third embodiment will be described with reference to the flowchart of FIG. The steps given the same reference numerals in FIG. 7 as in FIG. 4 of the first embodiment are the same as in the first embodiment. The configurations, processes, operations, and effects not particularly described in the third embodiment are the same as in the first embodiment, and only differences from the first embodiment will be described below.

  The failure determination process at engine restart according to the third embodiment executes the process of occurrence of a failure in step S240 when steps S200, S210, and S220 are all determined as YES in the failure determination process of the first embodiment. The point to do is different. According to the failure determination processing of the third embodiment, accurate AC resistance is detected in a situation where there is not much temperature difference between the low temperature side 10a and the high temperature side 10b, and failure determination excluding parameters highly dependent on temperature Can be implemented. Furthermore, since it is determined that a failure has occurred when the open circuit voltage detected after restart of the engine 20 exceeds the actual value of the open circuit voltage, the heat exchange performance after restart relative to the past heat exchange performance Can be compared with the According to the failure determination process of the third embodiment, it is possible to sufficiently improve the accuracy of the failure determination with respect to the technology of performing the failure determination using the conventional estimated value of the power generation amount based on the vehicle speed.

(Other embodiments)
The disclosure of this specification is not limited to the illustrated embodiments. The disclosure includes the illustrated embodiments and variations based on them by those skilled in the art. For example, the disclosure is not limited to the combination of parts and elements shown in the embodiments, and can be implemented with various modifications. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure includes the parts and components of the embodiments omitted. The disclosure includes replacements of parts, components, or combinations between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. The disclosed technical scope is defined by the description of the claims, and should be understood to include all modifications within the meaning and scope equivalent to the descriptions of the claims.

  In the above-described embodiment, the value of Rac0 used in the determination process in step S210 may be configured as a determination value that is appropriately rewritten in the control device 5 in consideration of aging deterioration or the like of the thermoelectric conversion element.

  The thermoelectric generator 10 of the above-described embodiment is not configured to be covered by a case, but a pipe in which a large number of P-type semiconductor elements and N-type semiconductor elements form a branch passage 31 and a pipe in which a circulation passage 27 is formed. It may be in contact with each other to generate a temperature difference on both sides. In the thermoelectric generator 10, the case is not an essential component.

  In the above embodiment, the first fluid and the second fluid may form counterflows flowing in opposite directions to each other.

5: control device, 10: thermoelectric generator 10a: low temperature side (one side), 10b: high temperature side (other side)
20 ... engine, 27 ... circulation passage (first fluid passage), 31 ... branch passage (second fluid passage)

Claims (6)

A first fluid passage (27) through which the first fluid flows;
A second fluid passage (31) which is hotter than the first fluid and through which the second fluid discharged from the engine (20) flows;
A thermoelectric conversion element is provided, the heat of the first fluid is movable to one side (10a), and the heat of the second fluid is movable to the other side (10b), A thermoelectric generator (10) generating electricity by the temperature difference between the one side and the other side;
A control device (5) capable of acquiring an open circuit voltage and an alternating current resistance for the thermoelectric generator;
Equipped with
The control device determines whether or not a failure occurs in the thermoelectric generator according to the detected AC resistance when the detected open circuit voltage falls below a reference value immediately before the engine is stopped and then restarted. Thermoelectric generator to determine. The control device stores a record value of the open circuit voltage detected during operation of the engine;
The control device detects the open circuit voltage detected after the restart of the engine when the detected open circuit voltage falls below the reference value and the detected alternating current resistance exceeds the determination value immediately before the engine restarts. The thermoelectric generation device according to claim 1, wherein it is determined that a failure has occurred when the open circuit voltage exceeds the actual value of the open circuit voltage.   The control device is configured such that the detected open circuit voltage falls below the reference value immediately before the engine restarts, the detected alternating current resistance exceeds the determination value, and the open detected after the engine is restarted When the estimated value of the power generation capacity determined using the detected AC resistance and the actual value of the open voltage is lower than the allowable level, when the voltage exceeds the actual value of the open voltage The thermoelectric power generation device according to claim 2, wherein it is determined that a failure has occurred.   The control device is configured such that the open circuit voltage detected at restart of the engine corresponds to the actual rotational speed of the engine at all the actual rotational speeds of the stored actual values of the open circuit voltage. The thermoelectric power generation device according to claim 2, wherein it is determined that a failure has occurred when the value exceeds the maximum value of the open circuit voltage.   The control device is configured such that the open circuit voltage detected at restart of the engine corresponds to all target rotational speeds of the open circuit voltage stored in association with the target rotational speed of the engine. The thermoelectric power generation device according to claim 2, wherein it is determined that a failure has occurred when the value exceeds the maximum value of the open circuit voltage.   The control device is configured such that the open circuit voltage detected at restart of the engine corresponds to the vehicle speed with respect to the maximum value of the open circuit voltage at all vehicle speeds among the stored actual values of the open circuit voltage. The thermoelectric power generation device according to claim 2, wherein it is determined that a failure has occurred if it exceeds the threshold.

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