JP2013147974A - Thermoelectric power generation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoelectric power generation device capable of detecting a failure of an on-off valve without using a dedicated sensor detecting actuation of the on-off valve.SOLUTION: A thermoelectric power generation device 17 comprises: an on-off valve 26 switching an exhaust route of exhaust gas to either one of a bypass passage 25 and a heat receiving passage 22 by opening and closing an inner pipe 21; and an actuator 37 controlling the opening and closing of the on-off valve 26. A CPU, when transmitting an opening signal or a closing signal to the actuator, diagnoses the presence/absence of a failure of the on-off valve 26 on the basis of a voltage value output from a voltage sensor already installed to an auxiliary battery.

Description

  The present invention relates to a thermoelectric power generator, and more particularly to a thermoelectric power generator that performs thermoelectric power generation using exhaust gas discharged from an internal combustion engine.

  Conventionally, since exhaust gas or the like discharged from an internal combustion engine of a vehicle such as an automobile contains thermal energy, if the exhaust gas is discarded as it is, the thermal energy is wasted. Therefore, the thermal energy contained in the exhaust gas is recovered by the thermoelectric generator and converted into electrical energy, and for example, the battery is charged.

  As a conventional thermoelectric power generator of this type, the high temperature part of the thermoelectric conversion module is brought into contact with the exhaust pipe into which the exhaust gas discharged from the internal combustion engine is introduced, and the cooling water flows through the low temperature part of the thermoelectric conversion module. Those in contact with water pipes are known.

  This thermoelectric conversion module is configured to include a thermoelectric conversion element such as a semiconductor, an electrode, a heat receiving substrate serving as a high-temperature portion, a heat-dissipating substrate serving as a low-temperature portion, and the like. The low-temperature cooling water pipe generates power by generating a temperature difference between the high temperature portion and the low temperature portion of the thermoelectric conversion module.

  By the way, the power generation efficiency of the thermoelectric conversion module increases as the temperature difference between the high temperature part and the low temperature part of the thermoelectric conversion module increases, but for example, a Bi-Te-based thermoelectric material that is frequently used as a thermoelectric conversion element is used. The thermoelectric conversion module has a heat resistant temperature of about 200 ° C., and the thermoelectric conversion module using the Mg—Si heat thermoelectric material has a heat resistant temperature of about 500 ° C.

  For this reason, if the heat resistance temperature is exceeded, the thermoelectric conversion elements and cables of the thermoelectric conversion module may be damaged due to heat damage, and the power generation efficiency may be reduced. Therefore, when the thermoelectric conversion module is used, it is necessary to obtain the best power generation efficiency by setting the temperature of the high temperature portion as high as possible below the heat resistant temperature.

  Conventionally, as a thermoelectric generator capable of improving power generation efficiency while preventing heat damage of a thermoelectric conversion module, for example, the one described in Patent Document 1 is known.

  This thermoelectric generator is provided with an exhaust pipe as an inner pipe into which exhaust gas discharged from an internal combustion engine is introduced, and an outer pipe that is provided outside the exhaust pipe and defines a heat shield space as a heat receiving passage together with the exhaust pipe. A thermoelectric conversion module that performs thermoelectric power generation according to a temperature difference between the high-temperature part and the low-temperature part, with the pipe and the high-temperature part in contact with the outer peripheral part of the outer pipe, And an opening / closing valve provided inside the exhaust pipe for opening and closing the exhaust pipe.

  The thermoelectric generator is provided on the upstream side of the exhaust pipe in the exhaust direction, provided on the exhaust gas introduction passage communicating the interior of the exhaust pipe and the heat shield space, and on the downstream side of the exhaust pipe in the exhaust direction. And an exhaust gas discharge passage communicating with the heat shield space.

  When the temperature rises above the upper limit use temperature of the thermoelectric conversion module, the thermoelectric power generator having such a configuration drives the on-off valve in the opening direction and communicates the exhaust pipe and the heat shield space through the exhaust gas introduction passage. By doing so, the flow rate of the exhaust gas flowing in the heat shield space is reduced.

  For this reason, the thermoelectric conversion module is damaged by lowering the surface temperature of the high-temperature portion of the thermoelectric conversion module by preventing the temperature of the thermoelectric conversion module from further rising by causing the heat shield space to act as a heat insulating layer. Can be prevented.

  Also, when the temperature of the exhaust gas is low, such as immediately after starting the engine or during idling, the temperature of the high-temperature part of the thermoelectric conversion module is reduced by closing the on-off valve and actively flowing the exhaust gas into the heat shield space. It can be raised early.

JP 2000-18095 A JP 2010-116843 A

  However, in such a conventional thermoelectric generator, since it does not include means for detecting the operating state of the on-off valve, unless the on-off valve fails and is switched between the open state and the closed state, The thermoelectric conversion module cannot generate power, and the thermoelectric conversion module cannot be prevented from being damaged due to heat damage.

  In general, a sensor such as a throttle sensor for opening and closing the throttle valve shown in Patent Document 2 is known as a sensor for detecting the open / closed state of the open / close valve. In such a case, a dedicated sensor is required, which increases the manufacturing cost of the thermoelectric generator, which is not preferable.

  The present invention has been made to solve the above-described conventional problems, and is capable of detecting a failure of the on-off valve without using a dedicated sensor for detecting the operation of the on-off valve. The purpose is to provide.

  In order to achieve the above object, a thermoelectric power generator according to the present invention includes (1) a first exhaust pipe that forms a bypass passage through which exhaust gas discharged from an internal combustion engine is introduced, and the first exhaust pipe; A second exhaust pipe provided on the same axis and forming a heat receiving passage with the first exhaust pipe; and a cooling water pipe in which a low temperature portion faces the first exhaust pipe and a cooling water flows. A thermoelectric conversion module that opposes a low-temperature part and performs thermoelectric generation according to a temperature difference between the high-temperature part and the low-temperature part, and opens and closes the first exhaust pipe so that an exhaust gas exhaust path is connected to the bypass path and the A thermoelectric generator that includes an opening / closing valve that switches to one of the heat receiving passages and an opening / closing control means that controls opening / closing of the opening / closing valve, and when an open signal or a closing signal is transmitted to the opening / closing control means Electrical characteristics of the thermoelectric conversion module And a having a failure diagnosis means for diagnosing the presence or absence of failure of the on-off valve based on the value.

  In this thermoelectric power generation device, when the on-off valve is opened, the exhaust gas discharged from the internal combustion engine is discharged outside through the first exhaust pipe without passing through the heat receiving passage. There is no power generation.

  Further, when the on-off valve is closed, the exhaust gas discharged from the internal combustion engine is introduced into the heat receiving passage and the amount of heat of the exhaust gas is transmitted to the high temperature portion of the thermoelectric conversion module, so that the thermoelectric conversion module generates power. Is called.

  Therefore, if the failure diagnosis means outputs an open signal to the opening / closing control means, the electrical characteristic value of the thermoelectric conversion module, for example, the voltage value increases if the opening / closing valve is not opened but is in the closed state. If the electrical characteristic value tends to increase, it is possible to diagnose a failure of the on-off valve.

  In addition, the failure diagnosis means includes the thermoelectric conversion module because the voltage value of the thermoelectric conversion module does not change if the opening / closing valve is not closed when the closing signal is output to the opening / closing control means. If the voltage value of the conversion module does not change, it can be diagnosed that the on-off valve is faulty.

  In this way, the failure diagnosis means can diagnose the presence / absence of the on / off valve failure based on the electrical characteristic value of the thermoelectric conversion module according to the on / off signal, so that a dedicated sensor for detecting on / off of the on / off valve is not required It is possible to prevent the manufacturing cost of the thermoelectric generator from increasing.

  In the thermoelectric generator of (1) above, (2) failure diagnosing means diagnoses the presence or absence of a failure of the on-off valve based on an electric characteristic value of a battery that stores electric power generated by the thermoelectric conversion module. It is composed of

  In this thermoelectric generator, the failure diagnosing means diagnoses the presence or absence of a failure of the on-off valve based on the electrical characteristic value of the battery according to the on-off signal. The presence or absence of a failure can be diagnosed, and an increase in the manufacturing cost of the thermoelectric generator can be prevented.

The thermoelectric generators of the above (1) and (2) are composed of (3) that diagnoses the failure of the on-off valve on condition that the temperature of the exhaust gas is equal to or higher than a predetermined temperature.
In this thermoelectric power generation device, the amount of heat transmitted to the thermoelectric conversion module is low when the exhaust gas temperature is low, so the power generation amount of the thermoelectric conversion module is reduced. In the case of high temperature, the electrical characteristic value of the thermoelectric conversion module can be detected with high accuracy by diagnosing the failure of the on-off valve.

In the thermoelectric generator of (2) above, (4) the failure diagnosing means is configured to perform a failure diagnosis of the on-off valve on condition that the vehicle is in steady running.
In this thermoelectric generator, when the vehicle is not in steady running, such as when the vehicle is accelerating or decelerating, the battery voltage value is unstable and the battery voltage value is stable while the battery voltage value varies greatly. By diagnosing the failure of the on-off valve during steady running of the vehicle, the electrical characteristic value of the thermoelectric conversion module can be detected with high accuracy.

  In the thermoelectric generators of the above (2) and (4), (5) the failure diagnosing unit stops power generation other than the thermoelectric conversion module during the failure diagnosis of the on-off valve, and the voltage value of the battery Based on the change, the system is configured to diagnose the on-off valve failure.

  In this thermoelectric power generation device, the failure diagnosis means stops the power generation other than the thermoelectric conversion module during the failure diagnosis, and based on the change in the voltage value of the battery that stores the electric power generated by the thermoelectric conversion module, Therefore, only the electric power from the thermoelectric conversion module is stored in the battery, and the failure of the on-off valve can be reliably diagnosed based on the change in the electrical characteristic value of the battery.

  ADVANTAGE OF THE INVENTION According to this invention, the thermoelectric power generator which can detect a failure of an on-off valve can be provided, without using the sensor for exclusive use which detects the action | operation of an on-off valve.

1 is a diagram illustrating an embodiment of a thermoelectric power generation device according to the present invention, and is a schematic configuration diagram of a vehicle including the thermoelectric power generation device. It is a figure which shows one Embodiment of the thermoelectric power generating apparatus which concerns on this invention, and is side surface sectional drawing of a thermoelectric power generating apparatus. It is a figure which shows one Embodiment of the thermoelectric power generating apparatus which concerns on this invention, and is a perspective view of a thermoelectric conversion module. 1 is a diagram illustrating an embodiment of a thermoelectric generator according to the present invention, and is a system configuration diagram of a vehicle. It is a figure which shows one Embodiment of the thermoelectric generator which concerns on this invention, and is a figure which shows the flowchart of a failure diagnosis program. It is a figure which shows one Embodiment of the thermoelectric power generating apparatus which concerns on this invention, and is a figure which shows the change of the voltage value of the battery in implementation of failure diagnosis processing. It is a figure which shows one Embodiment of the thermoelectric generator which concerns on this invention, and is a figure which shows the flowchart of another failure diagnosis program. It is a figure which shows one Embodiment of the thermoelectric power generating apparatus which concerns on this invention, and is a figure which shows the change of the voltage value of the battery in implementation of another failure diagnosis process.

  Hereinafter, embodiments of a thermoelectric generator according to the present invention will be described with reference to the drawings. In the present embodiment, a case where the thermoelectric generator is applied to a water-cooled multi-cylinder internal combustion engine mounted on a vehicle such as an automobile, for example, a four-cycle gasoline engine (hereinafter simply referred to as an engine) will be described. Yes. The engine is not limited to a gasoline engine.

1-8 is a figure which shows one Embodiment of the thermoelectric power generating apparatus which concerns on this invention.
First, the configuration will be described.
As shown in FIG. 1, an engine 1 as an internal combustion engine mounted on a vehicle such as an automobile is formed by mixing air supplied from an intake system and fuel supplied from a fuel supply system at an appropriate air-fuel ratio. After being supplied to the air-fuel mixture combustion chamber and combusted, the exhaust gas generated along with this combustion is discharged from the exhaust system to the atmosphere.

  The exhaust system includes an exhaust manifold 2 attached to the engine 1 and an exhaust pipe 4 connected to the exhaust manifold 2 via a spherical joint 3. The exhaust manifold 2 and the exhaust pipe 4 An exhaust passage is formed.

The spherical joint 3 allows moderate swinging of the exhaust manifold 2 and the exhaust pipe 4 and functions so as not to transmit the vibration and movement of the engine 1 to the exhaust pipe 4 or to attenuate and transmit them.
Two catalysts 5 and 6 are installed in series on the exhaust pipe 4, and the exhaust gas is purified by the catalysts 5 and 6.

  Among the catalysts 5 and 6, the catalyst 5 installed upstream in the exhaust gas exhaust direction in the exhaust pipe 4 is a so-called start catalyst (S / C). The catalyst 6 installed downstream in the exhaust direction is a so-called main catalyst (M / C) or underfloor catalyst (U / F).

  These catalysts 5 and 6 are constituted by, for example, a three-way catalyst. This three-way catalyst exhibits a purifying action in which carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) are collectively changed to harmless components by a chemical reaction.

  A water jacket is formed inside the engine 1, and the water jacket is filled with a coolant called long life coolant (LLC) (hereinafter simply referred to as coolant).

The cooling water is led out from the outlet pipe 8 attached to the engine 1 and then supplied to the radiator 7, and is returned from the radiator 7 to the engine 1 through the cooling water reflux pipe 9.
The radiator 7 cools the cooling water circulated by the water pump 10 by heat exchange with the outside air.

Further, a bypass pipe 12 is connected to the reflux pipe 9, and a thermostat 11 is interposed between the bypass pipe 12 and the reflux pipe 9. The amount of cooling water flowing through the pipe 12 is adjusted.
For example, during the warm-up operation of the engine 1, the amount of cooling water on the bypass pipe 12 side is increased to promote warm-up.

  A heater pipe 13 is connected to the bypass pipe 12, and a heater core 14 is provided in the middle of the heater pipe 13. The heater core 14 is a heat source for heating the passenger compartment using the heat of the cooling water.

  The air heated by the heater core 14 is introduced into the vehicle interior by the blower fan 15. A heater unit 16 is configured by the heater core 14 and the blower fan 15.

  The heater pipe 13 is provided with an upstream pipe 18 a for supplying cooling water to a thermoelectric generator 17 described later, and between the thermoelectric generator 17 and the reflux pipe 9, the thermoelectric generator 17 to the reflux pipe 9 are provided. A downstream pipe 18b for discharging the cooling water is provided.

  For this reason, when the exhaust heat recovery operation (details of this exhaust heat recovery operation will be described later) is performed in the thermoelectric generator 17, the cooling water flowing through the downstream pipe 18b flows through the upstream pipe 18a. It becomes higher than the temperature of the cooling water.

  On the other hand, the exhaust system of the engine 1 is provided with a thermoelectric power generation device 17 that recovers the heat of the exhaust gas discharged from the engine 1 and converts the heat energy of the exhaust gas into electrical energy. It is supposed to convert.

  As shown in FIG. 2, the thermoelectric generator 17 includes an inner pipe 21 as a first exhaust pipe into which the exhaust gas discharged from the engine 1 is introduced, and an outer pipe 21 provided outside the inner pipe 21. And an outer pipe 23 serving as a second exhaust pipe.

  The upstream end of the inner pipe 21 is connected to the exhaust pipe 4, and a bypass passage 25 into which exhaust gas is introduced from the exhaust pipe 4 is formed inside the inner pipe 21. The inner tube 21 is fixed to the outer tube 23 via a support member 24, and the downstream end of the outer tube 23 is connected to the tail pipe 19.

Therefore, the exhaust gas G discharged from the engine 1 through the exhaust pipe 4 to the bypass passage 25 of the inner pipe 21 is discharged to the tail pipe 19 through the bypass passage 25 and then discharged from the tail pipe 19 to the outside air.
In addition, the thermoelectric generator 17 includes a plurality of thermoelectric conversion modules 27 and a cylindrical cooling water pipe 28 that are installed in the exhaust direction of the exhaust gas G.

  As shown in FIG. 3, the thermoelectric conversion module 27 has a temperature difference due to the Seebeck effect between a heat receiving substrate 29 made of insulating ceramics constituting the high temperature portion and a heat dissipation substrate 30 made of insulating ceramics constituting the low temperature portion. A plurality of N-type thermoelectric conversion elements 31 and P-type thermoelectric conversion elements 32 that generate corresponding electromotive forces are installed, and the N-type thermoelectric conversion elements 31 and the P-type thermoelectric conversion elements 32 are alternately arranged via electrodes 33a and 33b. Connected in series. Adjacent thermoelectric conversion modules 27 are electrically connected via wiring 35.

  In this thermoelectric conversion module 27, the heat receiving substrate 29 faces the outer tube 23 and contacts the outer tube 23, and the heat dissipation substrate 30 faces the cooling water tube 28 and contacts the cooling water tube 28. It is installed in parallel with the exhaust direction. In FIG. 1, the thermoelectric conversion module 27 shown in FIG. 3 is simplified.

  The thermoelectric conversion module 27 supplies power to an auxiliary battery described later via the cable 34 by performing thermoelectric power generation according to the temperature difference between the heat receiving substrate 29 and the heat dissipation substrate 30.

  Since the thermoelectric conversion module 27 has a substantially square plate shape and needs to be in close contact between the outer tube 23 and the cooling water tube 28, the outer tube 23 and the cooling water tube 28 are formed in a polygonal shape. Yes.

Further, the outer tube 23 and the cooling water tube 28 may be circular. In this case, the heat receiving substrate 29 and the heat radiating substrate 30 of the thermoelectric conversion module 27 may be curved.
The cooling water pipe 28 includes a cooling water introduction part 28a connected to the upstream pipe 18a and a cooling water discharge part 28b connected to the downstream pipe 18b.

  This cooling water pipe 28 has a cooling water introduction part 28a with respect to the cooling water discharge part 28b so that the cooling water W introduced into the cooling water pipe 28 from the cooling water introduction part 28a flows in the same direction as the exhaust direction of the exhaust gas G. Is provided upstream in the exhaust direction.

  On the other hand, a plurality of communication holes 36 as communication portions are formed in the inner pipe 21, and the communication holes 36 communicate the inside of the inner pipe 21 and the heat receiving passage 22. The communication holes 36 are formed at equal intervals in the circumferential direction of the inner tube 21. The communication holes 36 are not limited to those formed at regular intervals.

  The support member 24 has communication holes 24a formed at equal intervals in the circumferential direction of the support member 24. The heat receiving passage 22 communicates with the tail pipe 19 through the communication holes 24a. The communication holes 24a are not limited to those formed at regular intervals.

  The inner pipe 21 is provided with an on-off valve 26. The on-off valve 26 is provided at the downstream end of the inner pipe 21, and is rotatably attached to the outer pipe 23 so as to open and close the inner pipe 21. ing. The on-off valve 26 is opened and closed by an actuator 37 serving as an opening / closing control means.

  As shown in FIG. 4, the actuator 37 is controlled by an ECU (Electronic Control Unit) 41, and the actuator 37 controls the opening / closing valve 26 based on an open signal and a close signal from the ECU 41. .

  The ECU 41 includes an electronic control circuit including a CPU (Central Processing Unit) 42, a ROM (Read Only Memory) 43, a RAM (Random Access Memory) 44, an input / output interface 45, and the like.

  The CPU 42 diagnoses the presence or absence of a failure of the on-off valve 26 based on a failure diagnosis program stored in the ROM 43. The ROM 43 includes a failure diagnosis program, and the RAM 44 temporarily stores data and configures a work area.

  On the other hand, as shown in FIGS. 1 and 4, the engine 1 is provided with an alternator 47 that charges an auxiliary battery 46 as a battery. The alternator 47 is driven by the engine 1 to generate electric power. The auxiliary battery 46 is charged.

  Further, the engine 1 is provided with a water temperature sensor 48. The water temperature sensor 48 detects the temperature of the cooling water flowing through the engine 1 and outputs detection information to the ECU 41. The water temperature sensor 48 may be provided in the heater pipe 13 or the like.

  The exhaust pipe 4 is provided with a temperature sensor 54. The temperature sensor 54 detects the temperature of the exhaust gas discharged to the exhaust pipe 4 and outputs detection information to the ECU 41.

  The vehicle is provided with a vehicle speed sensor 49. The vehicle speed sensor 49 is composed of, for example, a wheel speed sensor that detects the speed of the wheel of the vehicle, and outputs a detection signal to the ECU 41 by detecting the wheel speed. It is supposed to be.

  The ECU 41 acquires the vehicle speed based on the detection signal from the vehicle speed sensor 49, and calculates the acceleration or deceleration of the vehicle based on the change in the vehicle speed per unit time.

  The engine 1 is provided with a rotation speed sensor 50. The rotation speed sensor 50 detects the rotation speed of the crankshaft of the engine 1, for example, and outputs a signal corresponding to the engine rotation speed to the ECU 41. It is supposed to be.

  The cable 34 of the thermoelectric conversion module 27 is connected to the auxiliary battery 46 via the DCDC converter 51, and the DCDC converter 51 adjusts the direct current voltage output from the thermoelectric conversion module 27 to adjust the auxiliary battery 46. By applying the voltage to the auxiliary battery 46, the auxiliary battery 46 is charged.

  Further, the ECU 41 according to the present embodiment controls the opening / closing of the on / off valve 26 by driving the actuator 37 based on the engine speed output from the speed sensor 50.

Specifically, when the engine speed is in the low / medium speed range, the ECU 41 transmits a close signal to the actuator 37, and the actuator 37 moves the on-off valve 26 to the closed position as shown by a solid line in FIG. By doing so, the inner tube 21 is closed.
At this time, the exhaust gas introduced into the inner pipe 21 is introduced into the heat receiving passage 22 through the communication hole 36.

Further, when the engine speed is in the high speed range, the ECU 41 transmits an open signal to the actuator 37, and the actuator 37 moves the open / close valve 26 to the open position as shown by a broken line in FIG. 21 is released.
Further, the on-off valve 26 releases the inner pipe 21 in the high rotation range of the engine 1 where the exhaust gas pressure is high, as indicated by a broken line in FIG. For this reason, the thermoelectric power generation device 17 can prevent the exhaust gas from increasing in back pressure and prevent the exhaust performance from deteriorating.

  As shown in FIG. 4, the auxiliary battery 46 is provided with a voltage sensor 52, which detects the voltage of the auxiliary battery 46 and corresponds to the voltage value of the auxiliary battery 46. A detection signal is output to the ECU 41.

  The ECU 41 diagnoses a failure of the on-off valve 26 based on a change in the electrical characteristic value of the thermoelectric conversion module 27 when an open signal or a close signal is output to the actuator 37. It constitutes a diagnostic means.

  When the ECU 41 diagnoses that the on-off valve 26 is in failure, it outputs an abnormal signal to the warning lamp 53 (see FIG. 4). When the warning lamp 53 receives an abnormal signal from the ECU 41, the warning lamp 53 is lit or blinked to warn the driver. In the present embodiment, the voltage value of auxiliary battery 46 constitutes an electrical characteristic value. Further, the warning lamp 53 may warn by a sound such as a buzzer or a voice.

Next, the operation will be described.
When the engine 1 is cold started, the catalysts 5 and 6 and the cooling water of the engine 1 are all at a low temperature (about the outside temperature).

  When the engine 1 is started from this state, a low-temperature exhaust gas is discharged from the engine 1 to the exhaust pipe 4 through the exhaust manifold 2 as the engine 1 starts, and the two catalysts 5 and 6 are exhausted. The temperature is raised by the gas.

  Further, the cooling water is returned to the engine 1 through the bypass pipe 12 without passing through the radiator 7, so that the warm-up operation is performed.

  When the engine 1 is cold-started, for example, because the engine 1 is idling and the pressure of the exhaust gas is low, the ECU 41 outputs a close signal to the actuator 37 to close the on-off valve 26.

  For this reason, the exhaust gas introduced from the exhaust pipe 4 into the bypass passage 25 of the inner pipe 21 is introduced into the heat receiving passage 22, and the cooling water flowing through the cooling water pipe 28 is heated by the exhaust gas passing through the heat receiving passage 22, The engine 1 is warmed up.

Further, in the low / medium rotation range of the engine 1 after the engine 1 has been warmed up, the ECU 41 outputs a close signal to the actuator 37, so that the on-off valve 26 is closed.
At this time, since the exhaust gas introduced from the exhaust pipe 4 into the bypass passage 25 of the inner pipe 21 is introduced into the heat receiving passage 22, the thermoelectric conversion module 27 efficiently converts the thermal energy of the exhaust gas into electrical energy.

  Further, it is necessary to improve the cooling performance of the engine 1 in the high rotation range of the engine 1. In the high speed range of the engine 1, the ECU 41 outputs an open signal to the actuator 37 and releases the on-off valve 26.

  When the on-off valve 26 is released, the bypass passage 25 and the tail pipe 19 communicate with each other, and the exhaust gas does not flow through the heat receiving passage 22 but is directly discharged from the bypass passage 25 to the tail pipe 19. For this reason, the temperature of the cooling water flowing through the cooling water pipe 28 is not increased by the high-temperature exhaust gas. In addition, it is possible to prevent the thermoelectric conversion module 27 from being damaged by being exposed to high-temperature exhaust gas and not being damaged by heat.

  At this time, since the thermostat 11 blocks communication between the bypass pipe 12 and the reflux pipe 9, the cooling water led out from the engine 1 through the lead-out pipe 8 is led out to the reflux pipe 9 through the radiator 7. For this reason, low-temperature cooling water is supplied to the engine 1, and the cooling performance of the engine 1 can be enhanced.

  Further, since the on-off valve 26 is released in the high rotation range of the engine 1, the back pressure of the exhaust gas flowing through the bypass passage 25 does not increase, and it is possible to prevent the exhaust gas exhaust performance from being deteriorated. .

  Next, failure diagnosis processing of the thermoelectric conversion module 27 will be described based on the flowchart shown in FIG. Note that the flowchart of the failure diagnosis program shown in FIG. 5 is a failure diagnosis program stored in the ROM 43, and this failure diagnosis program is executed by the CPU.

  First, the CPU 42 determines whether or not the voltage of the auxiliary battery 46 is equal to or higher than the minimum level value based on the detection signal from the voltage sensor 52 (step S1). If the CPU 42 determines that the voltage of the auxiliary battery 46 is less than the minimum level value, the CPU 42 determines that the battery of the auxiliary battery 46 is likely to run out, and performs the current process without executing the failure diagnosis process. Exit.

If the CPU 42 determines that the voltage of the auxiliary battery 46 is equal to or higher than the minimum level value, the CPU 42 determines whether or not the vehicle is in steady running based on detection information from the vehicle speed sensor 49 (step S2).
If the CPU 42 determines that the vehicle is accelerating or decelerating, the CPU 42 determines that the voltage of the auxiliary battery 46 is unstable and ends the current process without executing the failure diagnosis process. To do. If the CPU 42 determines that the vehicle is in steady running, the CPU 42 determines that the voltage of the auxiliary battery 46 is in a stable state and determines the temperature of the exhaust gas based on detection information from the temperature sensor 54. Is determined to be equal to or higher than a predetermined temperature (step S3).

  When the CPU 42 determines that the temperature of the exhaust gas is lower than the predetermined temperature, the CPU 42 ends the current process without executing the failure diagnosis process. That is, when the temperature of the exhaust gas is low, the temperature of the exhaust gas transmitted to the heat receiving substrate 29 of the thermoelectric generator 17 is low, that is, the amount of heat of the exhaust gas is small and the power generation amount of the thermoelectric generator 17 is low.

  If the amount of power generated by the thermoelectric generator 17 is low, the voltage charged in the auxiliary battery 46 is low and the change in the voltage of the auxiliary battery 46 is small. Therefore, the operating state of the thermoelectric conversion module 27 cannot be accurately determined. Does not perform failure diagnosis processing of the thermoelectric conversion module 27.

  When determining that the temperature of the exhaust gas is equal to or higher than the predetermined temperature, the CPU 42 determines whether or not the water temperature is lower than the predetermined temperature based on detection information from the water temperature sensor 48 (step S4).

  If the CPU 42 determines that the water temperature is equal to or higher than the predetermined temperature, the CPU 42 determines that the temperature of the cooling water supplied to the engine 1 is high and the engine 1 is likely to be overheated. The current process is terminated without performing the diagnosis process.

  That is, when the temperature of the cooling water is high and the exhaust gas is introduced into the heat receiving passage 22 and heat exchange is performed between the cooling water and the exhaust gas, the temperature of the cooling water is further increased by the high-temperature exhaust gas. Then, an open signal is output to the actuator 37 to release the on-off valve 26 so that the exhaust gas is not introduced into the heat receiving passage 22. At this time, processing for preventing overheating of the engine 1 is performed by giving priority to cooling of the cooling water.

If the CPU 42 determines that the temperature of the cooling water is lower than the predetermined temperature, the CPU 42 stops power generation by the alternator 47 (step S5) and then outputs an open signal to the actuator 37 (step S6).
Next, the CPU 42 monitors the transition of the voltage value of the auxiliary battery 46 after outputting the open signal to the actuator 37 for a predetermined time (step S7).

Here, when the on-off valve 26 is opened, the exhaust gas discharged from the engine 1 is discharged to the tail pipe 19 through the inner pipe 21 without passing through the heat receiving passage 22, so that the thermoelectric conversion module 27 generates power. I will not.
For this reason, if the on-off valve 26 is operating normally so as to open in response to the open signal, the voltage value of the auxiliary battery 46 changes so as to decrease, as shown in FIG.

  When the on-off valve 26 is closed, the exhaust gas discharged from the engine 1 is introduced into the heat receiving passage 22, so that the thermoelectric conversion module 27 generates power and is stored in the auxiliary battery 46. For this reason, if the on-off valve 26 does not open in response to the open signal, that is, when the open / close valve 26 is closed, the voltage value of the auxiliary battery 46 increases as shown in FIG. 6B. To do.

  As a result of monitoring the transition of the voltage value of the auxiliary battery 46, the CPU 42 determines whether or not the voltage value of the auxiliary battery 46 is decreasing (step S8), and the voltage value of the auxiliary battery 46 is determined. If so, it is determined that the on-off valve 26 is operating normally, and the current process is terminated.

  Further, the CPU 42 determines that the on-off valve 26 is malfunctioning if the voltage value of the auxiliary battery 46 increases as a result of monitoring the change of the voltage value of the auxiliary battery 46 and warns. An abnormal signal is output to the lamp 53 (step S9), and the current process is terminated.

  When an abnormal signal is input from the CPU 42, the warning lamp 53 is lit or blinked to warn the driver that the on-off valve 26 is not operating normally.

  As described above, in the present embodiment, when the CPU 42 transmits an open signal to the actuator 37, whether or not the on-off valve 26 has failed is determined based on the voltage value output from the existing voltage sensor 52 to the auxiliary battery 46. Since the diagnosis is performed, a dedicated sensor for detecting the opening / closing of the on-off valve 26 is not required, and the manufacturing cost of the thermoelectric generator 17 can be prevented from increasing.

  In the present embodiment, since the CPU 42 diagnoses the failure of the on-off valve 26 on the condition that the temperature of the exhaust gas is equal to or higher than a predetermined temperature, the thermoelectric conversion module 27 is used when the exhaust gas temperature is low. On the other hand, when the exhaust gas temperature at which the power generation amount of the thermoelectric conversion module 27 is large and the exhaust gas temperature is high, the power generation amount of the thermoelectric conversion module 27 is reduced due to the low amount of heat transferred to. Can be implemented. For this reason, the voltage value of the auxiliary battery 46 can be detected with high accuracy.

  In addition, since the CPU 42 according to the present embodiment diagnoses the failure of the on-off valve 26 on the condition that the vehicle is in steady running, if the vehicle is not in steady running such as when the vehicle is accelerating / decelerating, etc. While the voltage value of the auxiliary battery 46 is large and the voltage value of the auxiliary battery 46 becomes unstable, the failure of the on-off valve 26 is diagnosed during steady running of the vehicle in which the voltage value of the auxiliary battery 46 is stable. Can be implemented. For this reason, the electrical characteristic value of the auxiliary battery 46 can be detected with high accuracy.

  Further, the CPU 42 according to the present embodiment stops power generation other than the thermoelectric conversion module 27 during the failure diagnosis of the on-off valve 26, and the failure of the on-off valve 26 is determined based on the change in the voltage value of the auxiliary battery 46. A diagnosis is being carried out.

  For this reason, only the electric power from the thermoelectric conversion module 27 is stored in the auxiliary battery 46, and the failure of the on-off valve 26 can be reliably diagnosed based on the change in the voltage value of the auxiliary battery 46.

  In this embodiment, the CPU 42 outputs an open signal to the actuator 37 to monitor the transition of the voltage value of the auxiliary battery 46. However, the present invention is not limited to this, and the CPU 42 outputs a close signal to the actuator 37. Thus, the transition of the voltage value of the auxiliary battery 46 may be monitored.

  Specifically, as shown in FIG. 7, after stopping the power generation of the alternator 47 (step S5), the CPU 42 outputs a close signal to the actuator 37 (step S16).

  Next, the CPU 42 monitors the transition of the voltage value of the auxiliary battery 46 after outputting the close signal to the actuator 37 for a predetermined time (step S17).

  Here, when the on-off valve 26 is closed, the exhaust gas discharged from the engine 1 is introduced into the heat receiving passage 22, so that the thermoelectric conversion module 27 generates power and is stored in the auxiliary battery 46. For this reason, if the on-off valve 26 is operating normally in response to the close signal, the voltage value of the auxiliary battery 46 changes so as to increase as indicated by A1 in FIG.

  When the on-off valve 26 is opened, the exhaust gas discharged from the engine 1 is discharged to the tail pipe 19 through the inner pipe 21 without passing through the heat receiving passage 22, so that the thermoelectric conversion module 27 generates power. Absent.

  For this reason, if the on-off valve 26 does not close in response to the close signal, that is, if the on-off valve 26 is opened, the voltage value of the auxiliary battery 46 decreases as shown in B1 of FIG. It changes as follows.

  As a result of monitoring the transition of the voltage value of the auxiliary battery 46, the CPU 42 determines whether or not the voltage value of the auxiliary battery 46 is increasing (step S18), and the voltage value of the auxiliary battery 46 is determined. If the transition is so as to increase, it is determined that the on-off valve 26 is operating normally, and the current process is terminated.

  Further, if the CPU 42 monitors the transition of the voltage value of the auxiliary battery 46 and the voltage value of the auxiliary battery 46 has decreased, the CPU 42 determines that the on-off valve 26 is malfunctioning and gives a warning. An abnormal signal is output to the lamp 53 (step S19), and the current process is terminated.

When applied to a hybrid vehicle that includes an internal combustion engine and an electric motor and has a high voltage battery that stores electric power of the electric motor instead of the vehicle having only the internal combustion engine, the process of step S5 is performed by the high voltage battery. The process is to stop charging the auxiliary battery.
As described above, when the CPU 42 transmits a close signal to the actuator 37, even if the on / off valve 26 is diagnosed for failure based on the voltage value output from the existing voltage sensor 52 to the auxiliary battery 46, the CPU 42 A dedicated sensor for detecting the opening / closing of the valve 26 is not required, and an increase in the manufacturing cost of the thermoelectric generator 17 can be prevented.

  In the present embodiment, the voltage value of the auxiliary battery 46 is detected by the voltage sensor 52 as the electric characteristic value. However, a sensor for detecting the current and electric power of the auxiliary battery 46 is provided to provide the electric characteristic value. A current value or a power value may be detected as the value.

  In the present embodiment, the CPU 42 monitors the transition of the voltage value of the thermoelectric conversion module 27 based on the voltage value of the auxiliary battery 46, but is not limited to this.

  For example, the CPU 42 detects a change in the voltage value of the thermoelectric conversion module 27 with a voltage sensor after outputting an open signal to the on-off valve 26, and if the voltage value of the thermoelectric conversion module 27 tends to increase, the thermoelectric conversion It may be determined that the module 27 has failed.

  Further, the CPU 42 detects a change in the voltage value of the thermoelectric conversion module 27 after outputting a close signal to the on-off valve 26 by a voltage sensor, and if the voltage value of the thermoelectric conversion module 27 tends to decrease, the thermoelectric conversion It may be determined that the module 27 has failed.

  As described above, the thermoelectric generator according to the present invention has the effect of being able to detect a failure of the on-off valve without using a dedicated sensor for detecting the operation of the on-off valve, and is discharged from the internal combustion engine. It is useful as a thermoelectric power generation apparatus that performs thermoelectric power generation using the exhaust gas generated.

1 engine (internal combustion engine)
17 Thermoelectric generator 21 Inner pipe (first exhaust pipe)
22 heat receiving passage 23 outer pipe (second exhaust pipe)
25 Bypass passage 26 On-off valve 27 Thermoelectric conversion module 28 Cooling water pipe 29 Heat receiving substrate (high temperature part)
30 Heat dissipation substrate (low temperature part)
37 Actuator (open / close control means)
41 ECU (failure diagnosis means)
46 Auxiliary battery
52 Voltage sensor (fault diagnosis means)

Claims (5)

A first exhaust pipe that forms a bypass passage through which exhaust gas discharged from the internal combustion engine is introduced, and the first exhaust pipe are provided coaxially, and a heat receiving passage is provided between the first exhaust pipe and the first exhaust pipe. The low temperature part faces the second exhaust pipe to be formed and the first exhaust pipe, and the low temperature part faces the cooling water pipe through which the cooling water flows, and according to the temperature difference between the high temperature part and the low temperature part A thermoelectric conversion module that performs thermoelectric power generation, an on-off valve that opens and closes the first exhaust pipe to switch an exhaust gas exhaust path to one of the bypass passage and the heat-receiving passage, and opens and closes the on-off valve. A thermoelectric generator comprising an opening / closing control means,
A thermoelectric generator having failure diagnosis means for diagnosing the presence or absence of a failure of the on-off valve based on an electrical characteristic value of the thermoelectric conversion module when an open signal or a close signal is transmitted to the open / close control means .   2. The thermoelectric generator according to claim 1, wherein the failure diagnosis unit diagnoses the presence or absence of a failure of the on-off valve based on an electrical characteristic value of a battery that stores electric power generated by the thermoelectric conversion module. .   3. The thermoelectric generator according to claim 1, wherein the failure diagnosis unit diagnoses the failure of the on-off valve on condition that the temperature of the exhaust gas is equal to or higher than a predetermined temperature.   The thermoelectric generator according to claim 2, wherein the failure diagnosis means diagnoses the failure of the on-off valve on condition that the vehicle is in steady running.   The failure diagnosing unit stops power generation other than the thermoelectric conversion module during the failure diagnosis of the on-off valve, and performs a diagnosis of the on-off valve failure based on a change in the voltage value of the battery. The thermoelectric power generator according to claim 2 or 4, wherein

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