WO2017221565A1

WO2017221565A1 - Thermoelectric power generation device

Info

Publication number: WO2017221565A1
Application number: PCT/JP2017/017514
Authority: WO
Inventors: 桑山　和利
Original assignee: 株式会社デンソー
Priority date: 2016-06-21
Filing date: 2017-05-09
Publication date: 2017-12-28
Also published as: JP2017229135A; JP6547694B2

Abstract

This thermoelectric power generation device is provided with: a first fluid path (27), in which a first fluid flows; a second fluid path (31), in which a second fluid at a temperature higher than that of the first fluid flows, said second fluid being discharged from an engine (20); a thermoelectric power generator (10), which has a thermoelectric conversion element, and which is provided such that heat of the first fluid can transfer to a first side section (10a), and heat of the second fluid can transfer to a second side section (10b), said thermoelectric power generator generating power by means of a temperature difference between the first side section and the second side section; and a control device (5) capable of acquiring an open voltage and alternating current resistance with respect to the thermoelectric power generator. Just before restarting the engine after an engine stop, the control device determines, corresponding to a detected alternating current resistance, whether a failure of the thermoelectric power generator has occurred or not, in the cases where a detected open voltage is lower than a reference value.

Description

Thermoelectric generator

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2016-122770 filed on June 21, 2016, the contents of which are incorporated herein by reference.

The disclosure in this specification relates to a thermoelectric generator that converts thermal energy into electric 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 detection value of the vehicle speed detected by the vehicle speed sensor and a predetermined map, and when the actual power generation amount of the thermoelectric converter is smaller than the estimated power generation amount, It is determined that the converter has failed.

JP 2007-14084 A

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 influenced by, for example, traveling loads related to acceleration, braking, etc. . For this reason, there is room for improvement in the accuracy of the power generation amount estimated based on the vehicle speed as in the device of Patent Document 1, and the failure determination using the estimated value of the power generation amount also has a problem in terms of the accuracy. .

An object of the present disclosure is to provide a thermoelectric generator that can improve the accuracy of failure determination.

A thermoelectric power generation device according to one aspect of the present disclosure includes a first fluid passage through which a first fluid flows, a second fluid passage at which the second fluid that is higher in temperature than the first fluid and discharged from an engine flows, and a thermoelectric conversion element The first side portion and the second side portion are provided so that the heat of the first fluid can move to the first side portion and the heat of the second fluid can move to the second side portion. And a control device capable of acquiring an open-circuit voltage and an AC resistance for the thermoelectric generator. The control device determines whether or not a failure of the thermoelectric generator has occurred 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 starting again after the engine is stopped is below the reference value. At this time, it can be determined that there is not much temperature difference between the first side portion and the second side portion, 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 an electrical resistance, becomes large. Since the thermoelectric generator determines whether or not a thermoelectric generator failure has occurred according to the AC resistance detected in such a situation, the failure excluding parameters with high temperature dependence that can vary in a complex manner depending on the load Judgment can be made. Therefore, according to this thermoelectric power generation device, the accuracy of failure determination can be improved as compared with the prior art in which failure determination is performed using an estimated value of the amount of power generation based on the vehicle speed.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. The drawing
It is the schematic which showed the relationship between the thermoelectric generator of 1st Embodiment, a cooling water, and waste gas, It is a control block diagram about the thermoelectric generator of 1st Embodiment, In the first embodiment, it is a flowchart for executing data accumulation processing during engine operation, In the first embodiment, it is a flowchart for executing a failure determination process at the time of engine restart, It is a graph showing the open circuit voltage for each engine speed, stored in the storage unit for failure determination processing, In 2nd Embodiment, it is a flowchart which performs a failure determination process at the time of engine restart, In 3rd Embodiment, it is a flowchart which performs a failure determination process 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. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly indicate that the combination is possible in each embodiment, but also a combination of the embodiments even if they are not clearly specified unless there is a problem with the combination. It is also possible.

(First embodiment)
A thermoelectric generator 1 according to a first embodiment will be described with reference to FIGS. The thermoelectric generator 1 is a device that converts thermal energy into electric energy by the Seebeck effect using a temperature difference between the exhaust gas as the second fluid discharged from the engine 20 and the first fluid that is lower in temperature than the exhaust gas. is there. The thermoelectric generator 1 generates a potential difference when a temperature difference is given between the low temperature side portion 10a that is the first side portion and the high temperature side portion 10b that is the second side portion in the thermoelectric generator 10 having the thermoelectric conversion element. Electricity is generated using the phenomenon of electrons flowing. Any fluid capable of giving a temperature difference from the exhaust gas can be adopted as the first fluid. In this embodiment, a case where cooling water of an automobile engine 20 is used as an example of an arbitrarily selectable low-temperature fluid will be described.

An engine 20 which is an internal combustion engine is connected to an intake pipe for sucking combustion air and an exhaust pipe 3 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 20 is controlled to an optimum operation by the engine control device 4. The engine control device 4 receives an engine speed signal, a throttle valve opening signal, a vehicle speed signal, and the like. The engine control device 4 stores in advance a control map in which the fuel injection amount is associated with the engine speed signal and the throttle valve opening signal. The engine control device 4 controls the fuel injection amount 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 5 of the thermoelectric generator 1 so as to be able to communicate with each other to exchange signals.

The cooling water 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. Cooling water passes through the radiator 21 from the outlet 20b through the water pump 24 and circulates through 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 controlled appropriately.

The cooling water circuit 2 is provided with a bypass passage 26 that bypasses the radiator 21 and a thermostat 22 that adjusts the flow rate of the cooling water 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 side is closed by the thermostat 22 and the cooling water flows through the bypass passage 26 side, thereby preventing the cooling water from being overcooled. This corresponds to a case where the cooling water is not sufficiently heated, for example, immediately after the engine 20 is started, and warm-up of the engine 20 can be promoted. Further, when the warm-up of the engine 20 is finished and the coolant temperature exceeds the first predetermined temperature, the thermostat 22 starts to open the radiator 21 side, closes the bypass passage 26 side at the second predetermined temperature or higher, and closes the radiator 21 side. 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 so as to be in parallel with 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 has a configuration in which a branch passage 31 that is a second fluid passage and a circulation passage 27 that is a first fluid passage are disposed with respect to a thermoelectric conversion element that generates power using the Seebeck effect. Has been. The branch passage 31 constitutes a passage formed so as to branch from the exhaust pipe 3 of the engine 20 and merge with the exhaust pipe 3 again, and is configured such that a part of the exhaust gas is diverted. The branch passage 31 comes into contact with the thermoelectric conversion element or the high temperature side portion 10b which is the second side surface of the thermoelectric generator 10, and the exhaust gas becomes a high temperature side heat source of the thermoelectric conversion element. An on-off valve 30 for opening and closing the branch passage 31 is provided on the upstream side of the exhaust gas with respect to the thermoelectric conversion element of the branch passage 31.

The circulation passage 27 is a passage closer to the engine 20 than the bypass passage 26, and is a passage connecting the thermostat 22 and the inlet portion 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 portion 10 a that is the first side surface of the thermoelectric generator 10. The cooling water flowing through the thermostat 22 from the bypass passage 26 or the cooling water passing through the radiator 21 and flowing through the thermostat 22 is supplied to the thermoelectric conversion element side, and this cooling water becomes a low temperature side heat source of the thermoelectric conversion element.

The control device 5 includes a device such as a microcomputer that operates 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, a storage unit 52, Is provided. The arithmetic processing unit 51 performs determination processing and arithmetic processing according to a predetermined program using information acquired from various sensors and various measuring devices through the I / F unit 50 and various data stored in the storage unit 52.

The storage unit 52 includes a writable storage medium, and temporarily stores information based on signals output from the detectors in the storage medium. The storage unit 52 is a non-transitional tangible storage medium. 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 and the calculation result by the calculation processing unit 51. 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 constitute a part of the engine control device 4.

The I / F unit 50 acquires engine speed, engine load information, and the like from the engine control device 4 as engine information signals. The engine load information is a torque value of the engine 20, for example. The rotation speed detector 40 is a sensor that detects the rotation speed of the engine 20. The arithmetic processing unit 51 performs arithmetic processing on various engine information signals from the engine control device 4 according to 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 a shaft torque map, a cooling loss heat amount map of the engine 20, a water flow rate map of the engine 20, a reference heat release amount map of the radiator 21, an 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 the failure determination of the thermoelectric generator 10 according to various information detected by the rotation 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 voltage in the thermoelectric generator 10 and outputs it to the control device 5. The open circuit voltage is also referred to as an open electromotive voltage. The open circuit voltage is data indicating the heat exchange performance of the thermoelectric generator 10, and cannot be accurately detected when the temperature difference between the low temperature side portion 10a and the high temperature side portion 10b is small. The control device 5 is configured to acquire data from the voltage detector 41 in accordance with the temperature difference between the low temperature side portion 10a and the high temperature side portion 10b. For example, the control device 5 acquires data from the voltage detector 41 when the temperature difference between the low temperature side portion 10a and the high temperature side portion 10b is large.

The resistance detector 42 detects the AC resistance of the thermoelectric generator 10 and outputs it to the control device 5. The AC resistance is data indicating the electric resistance of the thermoelectric generator 10, and cannot be accurately detected when the temperature difference between the low temperature side portion 10a and the high temperature side portion 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 portion 10a and the high temperature side portion 10b 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 and a portable terminal. The user can check the current driving state output from the I / F unit 50 through the display screen 53 of the control panel, the display screen of the terminal device, or the like. Moreover, the 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 a failure determination process executed by the thermoelectric generator 1 will be described with reference to FIGS. This failure determination process is a process for determining whether or not a failure has occurred so that the thermoelectric generator 10 cannot generate electricity normally when the engine 20 is restarted. The flowchart shown in FIG. 3 shows processing executed by the control device 5 during operation of the engine 20. In the flowchart shown in FIG. 3, during the operation of the engine 20, a process of storing the open circuit voltage Voc detected for each engine rotation speed as a performance value is performed. The flowchart shown in FIG. 4 shows processing executed by the control device 5 when restarting after the engine 20 is stopped.

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 S <b> 100. S100 is repeated until the engine 20 is operated. When the engine 20 is in operation, the maximum value Vocmax (Ne) of the open circuit voltage is set to zero and stored in the storage unit 52 in S110. Ne indicates the engine rotation speed when the open circuit voltage is detected. In 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 rotation speed as a set in association with the engine rotation speed at that time.

In S130, it is determined whether or not Voc (Ne) acquired in S120 is larger than Vocmax (Ne) stored in the storage unit 52. Since Voc (Ne) acquired first after the operation of the engine 20 is greater than zero, the arithmetic processing unit 51 determines YES in S130, and sets the Voc (Ne) to Vocmax (Ne) in S140. Execute. The storage unit 52 stores new Vocmax (Ne). Next, in S150, it is determined whether or not the ignition switch is in an off state.

If the ignition switch is not in the OFF state and the engine 20 is continuing to operate, the process returns to S120, and the control device 5 acquires the detected open-circuit voltage Voc as a set in association with the engine rotation speed. In S130, when it is determined that Voc (Ne) acquired in S120 is equal to or less than Vocmax (Ne) of the same level of rotation speed stored in the storage unit 52, the process returns to S120 to detect Voc and detect the rotation speed and Voc. And get as a set. Thus, until it determines with YES by S130, it acquires new Voc (Ne) during engine operation in S120, without rewriting acquired Voc (Ne) to Vocmax (Ne) by S140. In S130, when it is determined that Voc (Ne) acquired in S120 is larger than Vocmax (Ne) at the engine speed at the same level, processing for updating Vocmax (Ne) in S140 and storing it in the storage unit 52 is performed. Execute.

The actual value of Voc is memorize | stored in the memory | storage part 52 as an open circuit voltage value for every same engine speed, for example like the graph shown in FIG. You may comprise so that the performance value of Voc may be memorize | stored in the memory | storage part 52 as an open voltage value for every same engine target rotational speed, or as an open voltage value for every same vehicle speed.

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

4, each process of S200 and S220 is executed immediately before restarting the engine 20, that is, before the next operation of the engine 20 starts after the engine 20 is stopped. This is because the AC resistance of the thermoelectric generator 10 cannot be accurately detected when the thermoelectric generator 10 is heated by the exhaust gas and the temperature difference between the low temperature side portion 10a and the high temperature side portion 10b becomes large. The control device 5 can increase the accuracy of the failure determination by using the AC resistance value that is not affected by the temperature for the failure determination.

First, in S200, the arithmetic processing unit 51 determines whether or not the open circuit voltage Voc (0) acquired before starting is smaller than a predetermined reference value Vocmin. When Voc (0) immediately before starting the engine is a value equal to or higher than the reference value, the thermoelectric conversion element is in a warm state, and a temperature difference between the low temperature side portion 10a and the high temperature side portion 10b of the thermoelectric conversion element is generated. Therefore, an abnormal AC resistance value cannot be accurately detected, and an accurate failure determination cannot be made. The reference value Vocmin is set to a value that can detect a state that can be determined except for such a state, and is stored in the control device 5 in advance. If NO is determined in S200, since the thermoelectric conversion element is warm and the failure cannot be determined, this flowchart is terminated without determining whether or not a failure has occurred.

If YES is determined in S200, in S210, the arithmetic processing unit 51 determines whether or not the acquired AC resistance Rac detected by the resistance detector 42 is greater than a predetermined determination value Rac0 before starting. The determination value Rac0 is a value set in order to maintain that the power generation capacity required for the thermoelectric generator 10 as a product can be output. For example, the determination value Rac0 is a value that is set on the basis of the fact that when Rac exceeds this value, it is in a state where the necessary power generation capacity cannot be exhibited. If it is determined NO in S210, it can be determined that the thermoelectric generator 10 is in a state capable of outputting the necessary power generation capability and is normal, and this flowchart is terminated.

If YES is determined in S210, then in S220, the arithmetic processing unit 51 determines whether or not Voc0 (Ne) detected after the engine 20 is started is greater than Vocmax (Ne) stored in the storage unit 52. . 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 Voc value in each column among the data arranged in a row in the vertical direction in the graph of FIG. In the graph of FIG. 5, a plurality of pieces of data arranged in a line in the vertical direction are actual values of the open-circuit voltage Voc detected at the same level of rotation speed. Therefore, when Voc0 in the determination process of S220 is larger than Vocmax (Ne) for all the rotation speeds shown in FIG. 5, it is determined as YES, and otherwise it is determined as NO. As described above, in S220, whether or not the open-circuit voltage value detected when the engine 20 is restarted is greater than the maximum open-circuit voltage value at all actual rotation speeds among the stored actual open-circuit voltage values. Determine whether.

If it is determined NO in S220, it is determined that the present embodiment is normal, and this flowchart ends. If it determines with YES by S220, the arithmetic processing part 51 will determine whether the estimated value of the power generation capability estimated from the track record value of an open circuit voltage has fallen from the allowable level by S230. If it is determined NO in S230, this flowchart is terminated without determining that the thermoelectric generator 10 has failed. If YES is determined in S230, the thermoelectric generator 10 is in a state where the desired power generation capability cannot be exhibited. Therefore, a failure occurrence process is executed in S240, and this flowchart is terminated. For example, the control device 5 performs a process of notifying the user by displaying on the display unit 53 that the failure has occurred or notifying by voice or the like.

In S230, it is determined whether or not a 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 determination value Ptegf. The determination value Ptegf is set to a value corresponding to, for example, a case where the power generation performance of the thermoelectric generator 10 has fallen beyond an allowable level from a 100% capacity state.

* Pteg / Pteg0 is calculated by the following equation.

Pteg / Pteg0 = (Vocmax / Voc0) ² / (Rac / Rac0)
Further, Pteg is expressed by Voc ² / Rac, and Pteg0 is expressed by Voc0 ² / Rac0.

Next, the operational effects brought about by the thermoelectric generator 1 of the first embodiment will be described. The thermoelectric generator 1 can acquire 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 AC resistance of the thermoelectric generator 10. The control device 5 is provided. The thermoelectric generator 10 has a thermoelectric conversion element, is provided so that the heat of the cooling water can move to the low temperature side portion 10a, and the heat of the exhaust gas can move to the high temperature side portion 10b. Power is generated by the temperature difference between 10a and the high temperature side portion 10b. The control device 5 determines whether or not a failure has occurred in the thermoelectric generator 10 according to the detected AC resistance when the detected open-circuit voltage falls below the reference value immediately before the engine 20 is stopped and restarted. .

According to this thermoelectric generator 1, when the open circuit voltage detected immediately before starting again after the engine 20 is stopped is below the reference value, the thermoelectric generator 10 is not warmed. This state can be determined that there is not much temperature difference between the low temperature side portion 10a and the high temperature side portion 10b, and the AC resistance of the thermoelectric generator 10 can be accurately detected. 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 an electrical resistance, becomes large. The thermoelectric generator 1 determines whether or not a failure has occurred 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 with high temperature dependence that can fluctuate complicatedly depending on the load. According to the thermoelectric generator 1, the accuracy of failure determination can be sufficiently improved compared to the conventional technology for performing failure determination using an estimated value of power generation based on the vehicle speed.

Just before the engine 20 is restarted, the controller 5 detects that the detected open voltage is lower than the reference value, the detected AC resistance is higher than the determination value, and the open voltage detected after the engine 20 is restarted is the actual result of the open voltage. If it exceeds the value, make a decision regarding the power generation capacity. 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 determination, in addition to the determination processing that excludes parameters with high temperature dependence and the determination processing that compares the heat exchange performance after restart with respect to the past heat exchange performance, the estimated power generation capacity is further allowed. It is possible to provide a failure determination in which a determination is made as to whether or not the level is secured. Therefore, the accuracy of failure determination can be remarkably improved compared to the conventional technology for performing failure determination using the estimated value of the power generation amount based on the vehicle speed.

(Second Embodiment)
The failure determination process at the time of engine restart in the second embodiment will be described with reference to the flowchart of FIG. In FIG. 6, steps denoted by the same reference numerals as those in FIG. 4 of the first embodiment are the same as those in the first embodiment. The configuration, processing, operation, 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 the time of engine restart of the second embodiment is that the failure occurrence process of S240 is executed when both S200 and S210 are determined to be YES with respect to the failure determination process of the first embodiment. Is different. According to the failure determination process of the second embodiment, an accurate AC resistance can be detected in a situation where there is not much temperature difference between the low temperature side portion 10a and the high temperature side portion 10b. The failure determination of the device 10 can be performed. According to this failure determination process, it is possible to sufficiently improve the accuracy of failure determination over the conventional technology that performs failure determination using the estimated value of the power generation amount based on the vehicle speed.

(Third embodiment)
The failure determination process at the time of engine restart in the third embodiment will be described with reference to the flowchart of FIG. In FIG. 7, steps denoted by the same reference numerals as those in FIG. 4 of the first embodiment are the same as those in the first embodiment. The configuration, processing, operation, and effects not particularly described in the third embodiment are the same as those in the first embodiment, and only differences from the first embodiment will be described below.

The failure determination processing at the time of engine restart according to the third embodiment executes the failure occurrence processing at S240 when S200, S210, and S220 are all determined to be YES with respect to the failure determination processing according to the first embodiment. The point is different. According to the failure determination processing of the third embodiment, failure determination is performed by detecting an accurate AC resistance in a situation where there is not much temperature difference between the low temperature side portion 10a and the high temperature side portion 10b and excluding a parameter having high temperature dependency. Can be implemented. Furthermore, in order to determine 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 is compared with the past heat exchange performance. Can be performed. According to the failure determination process of the third embodiment, the accuracy of failure determination can be sufficiently improved as compared with the conventional technology that performs failure determination using the 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 encompasses the illustrated embodiments and variations by those skilled in the art based thereon. For example, the disclosure is not limited to the combination of components and elements shown in the embodiments, and various modifications can be made. The disclosure can be implemented in various combinations. The disclosure may have additional parts that can be added to the embodiments. The disclosure includes those in which the components and elements of the embodiment are omitted. The disclosure encompasses parts, element replacements, or combinations between one embodiment and another. The technical scope disclosed is not limited to the description of the embodiments. The technical scope disclosed is indicated by the description of the claims, and should be understood to include all modifications within the meaning and scope equivalent to the description of the claims.

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

The thermoelectric generator 10 according to the above-described embodiment is not configured to be covered with a case, and a large number of P-type semiconductor elements and N-type semiconductor elements are divided into a pipe that forms the branch passage 31 and a pipe that forms the circulation passage 27. The structure which contacts and a temperature difference generate | occur | produces on both sides may be sufficient. In the thermoelectric generator 10, the case is not an essential component.

In the above-described embodiment, the first fluid and the second fluid may form counterflows that flow in opposite directions.

Claims

A first fluid passage (27) through which the first fluid flows;
A second fluid passage (31) through which a second fluid that is hotter than the first fluid and discharged from the engine (20) flows;
A thermoelectric conversion element is provided, and the heat of the first fluid can be moved to the first side part (10a), and the heat of the second fluid can be moved to the second side part (10b). A thermoelectric generator (10) for generating electricity by a temperature difference between the first side and the second side;
A control device (5) capable of acquiring an open-circuit voltage and an AC resistance for the thermoelectric generator;
With
The control device determines whether or not a failure of the thermoelectric generator has occurred according to the detected AC resistance when the detected open-circuit voltage falls below a reference value immediately before the engine is stopped and restarted. The thermoelectric generator to judge.
The control device stores the actual value of the open-circuit voltage detected during operation of the engine,
The control device detects the detected open circuit voltage after restarting the engine when the detected open circuit voltage is lower than the reference value and the detected AC resistance exceeds a determination value immediately before the engine restarts. The thermoelectric generator according to claim 1, wherein it is determined that a failure has occurred when an open circuit voltage exceeds the actual value of the open circuit voltage.
The controller is configured to detect the open circuit detected immediately after the engine restarts, in which the detected open circuit voltage is less than the reference value, the detected AC resistance is greater than the determination value, and further detected after the engine is restarted. When the voltage exceeds the actual value of the open-circuit voltage, a failure occurs 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 an allowable level. The thermoelectric power generator according to claim 2, wherein it is determined that the occurrence has occurred.
The control device is configured so that the open-circuit voltage detected at the time of restarting the engine is the actual value of the open-circuit voltage stored in association with the actual rotational speed of the engine at all the actual rotational speeds. The thermoelectric generator according to claim 2, wherein it is determined that a failure has occurred when the maximum value of the open circuit voltage is exceeded.
The control device is configured so that the open-circuit voltage detected at the time of restarting the engine is the actual value of the open-circuit voltage stored in association with the target rotational speed of the engine at all the target rotational speeds. The thermoelectric generator according to claim 2, wherein it is determined that a failure has occurred when the maximum value of the open circuit voltage is exceeded.
The control device is configured such that the open-circuit voltage detected at the time of restarting the engine is the maximum value of the open-circuit voltage at all vehicle speeds among the actual values of the open-circuit voltage stored in association with the vehicle speed. The thermoelectric generator according to claim 2, wherein it is determined that a failure has occurred when the number exceeds.