JP6680729B2 - Exhaust heat recovery unit and exhaust heat recovery system - Google Patents

Description

  The present invention relates to an exhaust heat recovery unit and an exhaust heat recovery system. More specifically, the present invention is capable of independently switching between execution and non-execution of heat exchange by a heat recovery device and thermoelectric conversion by a thermoelectric generator while reducing the size and complexity of the unit. The present invention relates to a recovery unit and an exhaust heat recovery system.

  From the viewpoint of energy saving, it has been conventionally studied to reuse exhaust heat from a heat source such as an internal combustion engine without wasting it. As a method widely adopted at the present time, for example, a heat collector (heat collector) that heats a cooling medium of an internal combustion engine with exhaust heat to accelerate warming up, and a thermoelectric power generation device that converts the exhaust heat into electricity, etc. Can be mentioned.

  For the purpose of more effective utilization of exhaust heat, integration of a heat recovery device and a thermoelectric generator as one exhaust heat recovery unit and interposing them in an exhaust pipe of an internal combustion engine is also under study. Specifically, for example, there is known an integrated exhaust heat recovery unit in which a heat recovery device is arranged on the upstream side of a flow of exhaust gas and a thermoelectric power generation device is arranged on the downstream side in series (for example, see Patent Document 1). ). However, in such an arrangement, the heat recovery unit on the upstream side takes heat of the exhaust gas before the thermoelectric generation device on the downstream side, so that the temperature of the exhaust gas reaching the thermoelectric generation device becomes low and the thermoelectric generation device becomes low. The power generation efficiency in may decrease.

  Therefore, in order to solve the above problem, an integrated exhaust heat recovery unit has been proposed in which a thermoelectric power generation device is arranged on the upstream side and a heat recovery device is arranged on the downstream side in series in the flow of exhaust gas (for example, see Patent Document 2). . However, in such an arrangement, the thermoelectric generator on the upstream side takes heat of the exhaust gas before the heat recovery device on the downstream side, so that the temperature of the exhaust gas reaching the heat recovery device becomes low and the heat recovery device The heating efficiency of the cooling medium may deteriorate.

  Further, when the temperature of the cooling medium of the internal combustion engine becomes equal to or higher than a predetermined temperature (for example, 80 ° C.), it becomes difficult to sufficiently lower the temperature of the cooling medium due to heat radiation in the radiator, and it becomes difficult to sufficiently cool the internal combustion engine. There is a risk of becoming. In such a case, it is desirable to perform only power generation by the thermoelectric power generation device without performing heat recovery by the heat recovery device.

  As described above, in the integrated exhaust heat recovery unit including both the heat recovery device and the thermoelectric power generation device, not only when both the heat recovery device and the thermoelectric power generation device should be operated, but also the heat recovery device and the thermoelectric power generation device. In some cases, only one of them should be operated. However, heat recovery is performed in the integrated exhaust heat recovery unit (hereinafter, may be referred to as “series integrated exhaust heat recovery unit”) in which the heat recovery device and the thermoelectric generator are arranged in series as described above. It is difficult to independently operate only one of the reactor and the thermoelectric generator.

  If a mechanism (for example, a switching valve) that individually switches the supply of the cooling medium to the heat recovery unit and the thermoelectric generator is provided in the series integrated exhaust heat recovery unit, heat exchange by the heat recovery unit and thermoelectric generation by the thermoelectric generator can be performed. It becomes possible to independently switch between execution and non-execution of conversion. However, the addition of such a mechanism leads to an increase in size and complexity of the unit, resulting in an increase in the weight and manufacturing cost of the unit.

  Further, if the temperature of the exhaust gas reaching the thermoelectric power generator is excessively high, the temperature difference between the high heat source side and the low heat source side of the thermoelectric conversion element that constitutes the thermoelectric power generation device becomes excessive, and the thermoelectric conversion element is damaged. May lead to. In such a case, it is desirable to stop the supply of high-temperature exhaust gas to the thermoelectric power generator, but in the series integrated exhaust heat recovery unit, it is difficult to individually stop the supply of exhaust gas to the thermoelectric power generator. Is.

  Of course, if the heat recovery device and the thermoelectric power generation device are separately provided, not only the heat exchange by the heat recovery device and the execution and non-execution of the thermoelectric conversion by the thermoelectric power generation device can be switched individually but also the thermoelectric power generation device can be switched. It is also possible to individually stop only the supply of exhaust. However, providing the heat recovery device and the thermoelectric power generator separately in this manner leads to further increase in size and complexity of the integrated exhaust heat recovery unit and further increase in weight and manufacturing cost.

JP, 2016-102446, A JP, 2016-109018, A

  As described above, in the technical field, it is possible to independently switch between execution and non-execution of heat exchange by the heat recovery device and thermoelectric conversion by the thermoelectric generator while reducing the size and complexity of the unit. There is a need for a mold exhaust heat recovery unit. The present invention has been made to meet such a demand.

  In view of the above, the exhaust heat recovery unit according to the present invention (hereinafter, may be referred to as “the present invention unit”) is an integrated exhaust heat recovery unit including a thermoelectric power generator and a heat recovery device. Is. The thermoelectric power generation device generates power by the temperature difference between the exhaust gas discharged from the internal combustion engine and the cooling medium flowing into the internal combustion engine. The heat recovery device applies the heat recovered from the exhaust gas discharged from the internal combustion engine to the cooling medium. In the unit of the present invention, the thermoelectric generator and the heat recovery device are housed in a common housing, and the thermoelectric generation device and the heat recovery device are arranged in parallel with respect to the flow of exhaust gas. The coolant flow path, which is the flow path of the cooling medium in the housing, is configured such that the cooling medium reaches the heat recovery device after reaching the thermoelectric generator.

  In addition, an exhaust heat recovery system according to the present invention (hereinafter, may be referred to as “the present invention system”) includes the above-described present invention unit, a switching mechanism, and a control device. System. The switching mechanism is a mechanism configured to switch the opening and closing of the exhaust gas supply path to the thermoelectric generator and the heat recovery device, which form the unit of the present invention, independently of each other. The control device is configured to control the switching mechanism to switch the supply of exhaust gas to the thermoelectric generator and the heat recovery device.

  As described above, in the unit of the present invention, the thermoelectric generator and the heat recovery device are arranged in parallel with respect to the flow of exhaust gas. Therefore, as compared with the above-mentioned series integrated exhaust heat recovery unit, the unit can be made smaller and the pressure loss of exhaust can be made smaller.

  Also, unlike the series integrated exhaust heat recovery unit, the upstream side of the thermoelectric generator and the heat recovery unit is more downstream than the downstream side to remove heat from the exhaust gas. There is no fear that the temperature of the exhaust gas that reaches will be low and that the power generation efficiency or the heating efficiency of the cooling medium in the downstream side will decrease.

  Further, as described above, in the series integrated exhaust heat recovery unit, exhaust gas is always supplied to both the heat recovery device and the thermoelectric generator. Therefore, in order to independently switch execution and non-execution of heat exchange by the heat recovery device and thermoelectric conversion by the thermoelectric power generation device, a mechanism for individually switching the supply of the cooling medium to the heat recovery device and the thermoelectric power generation device (for example, It is necessary to install a switching valve, etc.). That is, a cooling medium flow path (refrigerant flow path) having a complicated structure is required, which causes an increase in size and complexity of the unit.

  On the other hand, in the unit of the present invention, the thermoelectric generator and the heat recovery device are arranged in parallel with the flow of exhaust gas. Therefore, according to the unit of the present invention, by switching the supply of the exhaust gas to the thermoelectric power generator and the heat recovery device, execution and non-execution of heat exchange by the heat recovery device and thermoelectric conversion by the thermoelectric power generation device are independently switched. be able to. Therefore, in the unit of the present invention, it is not necessary to provide a mechanism for individually switching the supply of the cooling medium to the heat recovery device and the thermoelectric generator. As a result, as described above, the refrigerant passage can be configured so that the cooling medium reaches the heat recovery device after reaching the thermoelectric generation device in the housing that houses the thermoelectric generation device and the heat recovery device. In other words, according to the unit of the present invention, it is possible to employ a refrigerant flow path having a simple structure in which the cooling medium is constantly supplied to both the thermoelectric generator and the heat recovery device, so that the size of the unit is increased. And complexity can be avoided.

  In addition, in the system of the present invention which is the exhaust heat recovery system including the unit of the present invention, the switching mechanism and the control device as described above, the control device controls the switching mechanism to exhaust the gas to the thermoelectric generator and the heat recovery device. Can be switched independently of each other. Therefore, according to the unit of the present invention and the system of the present invention, the heat exchange by the heat recovery unit and the thermoelectric generation by the thermoelectric power generator are performed according to the states of the internal combustion engine and the exhaust heat recovery unit while reducing the size and complexity of the unit. The conversion can be switched independently between execution and non-execution.

  Other objects, other features and attendant advantages of the present invention will be easily understood from the description of each embodiment of the present invention described with reference to the following drawings.

It is a typical sectional view showing one example of composition of the exhaust heat recovery unit (the 1st unit) concerning a 1st embodiment of the present invention. It is a typical sectional view showing another example of composition of the 1st unit. It is a typical sectional view showing one example of composition of an exhaust heat recovery system (3rd system) concerning a 3rd embodiment of the present invention. It is a typical sectional view showing another example of composition of the 3rd system. It is a typical sectional view showing one example of composition of an exhaust heat recovery system (4th system) concerning a 4th embodiment of the present invention. It is a typical sectional view showing another example of composition of the 4th system. It is a typical sectional view showing one example of composition of the exhaust heat recovery system (5th system) concerning a 5th embodiment of the present invention. It is a typical sectional view showing another example of composition of the 5th system. It is a typical sectional view showing one example of composition of an exhaust heat recovery system (sixth system) concerning a 6th embodiment of the present invention. It is a typical sectional view showing another example of composition of the 6th system. It is a top view (plan view) in the posture at the time of use of the exhaust heat recovery unit (1st Example unit) which concerns on Example 1 of this invention. It is a front view when the 1st Example unit is seen from the upstream side of the flow of exhaust gas. It is a side sectional view when the 1st example unit is seen from the right side to the flow of exhaust gas. FIG. 12 is a cross-sectional view of the unit of the first embodiment taken along a plane including line AA shown in FIG. 11. It is a typical sectional view in the posture at the time of use of the exhaust heat recovery system (the 2nd example system) concerning Example 2 of the present invention. FIG. 8 is a schematic cross-sectional view showing one example of a switching state of exhaust gas supply channels in the second embodiment system. FIG. 9 is a schematic cross-sectional view showing another example of switching states of the exhaust supply flow paths in the second embodiment system. It is a typical sectional view in the posture at the time of use of the exhaust heat recovery unit (modification of the unit of the 2nd example) concerning the modification of Example 2 of the present invention. FIG. 9 is a schematic cross-sectional view showing one example of a switching state of exhaust gas supply flow paths in a modification of the second embodiment system. It is a typical sectional view in the posture at the time of use of the exhaust heat recovery system (third embodiment system) according to the third embodiment of the present invention. FIG. 9 is a schematic cross-sectional view showing one example of a switching state of exhaust gas supply channels in the third embodiment system. FIG. 11 is a schematic cross-sectional view showing another example of switching states of the exhaust supply flow paths in the system of the third embodiment. FIG. 13 is a schematic cross-sectional view showing still another example of switching states of the exhaust gas supply flow paths in the third embodiment system.

<< 1st Embodiment >>
Hereinafter, the exhaust heat recovery unit according to the first embodiment of the present invention (hereinafter may be referred to as “first unit”) will be described.

  The first unit is an integrated exhaust heat recovery unit that includes a thermoelectric generator and a heat recovery device. The thermoelectric power generation device generates power by the temperature difference between the exhaust gas discharged from the internal combustion engine and the cooling medium flowing into the internal combustion engine. The configuration of such a thermoelectric generator is not particularly limited as long as it can generate electricity by the temperature difference between the exhaust gas and the cooling medium. As a specific example of the configuration of the thermoelectric power generator, for example, one of the junction points of the thermoelectric conversion element by the Seebeck effect is arranged as a high heat source (exhaust) and the other is arranged as a low heat source (cooling medium) so that heat conduction is possible. A configuration in which thermal energy is converted into electric power energy by generating a potential difference between the two can be mentioned.

  Further, by increasing the contact area between the joint on the high heat source side of the thermoelectric conversion element and the exhaust gas and / or the joint on the low heat source side of the thermoelectric conversion element and the cooling medium, heat exchange between these is increased. For the purpose of promotion, fins or the like may be provided inside the exhaust gas flow path and / or at a position where heat can be conducted to the junction point on the low heat source side of the thermoelectric conversion element.

  The heat recovery device applies the heat recovered from the exhaust gas discharged from the internal combustion engine to the cooling medium flowing into the internal combustion engine. The configuration of such a heat recovery device is not particularly limited as long as it is possible to apply the heat recovered from the exhaust gas to the cooling medium. As a specific example of the heat recovery device, for example, a member (for example, a pipe) that defines the flow passage from an exhaust gas that flows inside a predetermined flow passage (for example, a pipe) to a cooling medium that flows outside the flow passage. A heat exchanger or the like that transfers heat via a wall or the like) can be used. Conversely, the cooling medium may flow inside the predetermined flow path, and the exhaust gas may flow outside the flow path. Further, fins or the like may be provided outside and / or inside the flow passage for the purpose of increasing the contact area between the member defining the predetermined flow passage and the exhaust and / or cooling medium.

  In the first unit, the thermoelectric generator and the heat recovery device are housed in a common housing. The term "common housing" as used herein means that the internal space of the housing is one continuous space. Therefore, the housing may be constituted by a single container that houses both the thermoelectric generator and the heat recovery device. Alternatively, the housing comprises, for example, separate containers for accommodating the thermoelectric power generator and the heat recovery unit, respectively, and the internal spaces of the separate containers communicate with each other, unless the flow of the cooling medium is unduly obstructed. It may have been done.

  By circulating the cooling medium flowing into the internal combustion engine through the internal space of the housing, the cooling medium is always supplied to both the thermoelectric generator and the heat recovery device, and the cooling medium is supplied from both the thermoelectric generation device and the heat recovery device. It is possible to easily configure a refrigerant flow path that can always receive heat by the cooling medium. Moreover, since a mechanism (for example, a switching valve) that individually switches the supply of the cooling medium to the collector and the thermoelectric generator is not required, it is possible to avoid an increase in size and complexity of the unit.

  Further, the thermoelectric generator and the heat recovery device are arranged in parallel with respect to the flow of exhaust gas. The configuration "arranged in parallel with the flow of exhaust gas" here means that the exhaust gas discharged from the internal combustion engine is supplied to either the thermoelectric generator or the heat recovery unit and then to the other. It means that the exhaust gas emitted from the internal combustion engine can be supplied to both the thermoelectric generator and the heat recovery device at the same time, instead of being “arranged in series with respect to the flow of exhaust gas”. .

  As described above, in the first unit, the thermoelectric generator and the heat recovery device are arranged in parallel with respect to the flow of exhaust gas. Therefore, as compared with the above-mentioned series integrated type exhaust heat recovery unit, the unit can be made smaller and the pressure loss of the exhaust can be made smaller. Further, unlike the series integrated exhaust heat recovery unit, the upstream side of the thermoelectric generator and the heat recovery unit is located on the downstream side to remove the heat of the exhaust before the downstream side. There is no risk that the temperature of the exhaust gas that reaches the lower side will decrease and the power generation efficiency or the heating efficiency of the cooling medium in the downstream side will decrease.

  In addition, as described in detail later, by combining with a mechanism for switching the supply of exhaust gas to the thermoelectric power generator and the heat recovery device, heat exchange by the heat recovery device and thermoelectric conversion by the thermoelectric power generation device are performed and non-execution, respectively. Can be switched independently. Therefore, as described above, in the first unit, there is no need to provide a mechanism for individually switching the supply of the cooling medium to the heat recovery device and the thermoelectric generator. Therefore, according to the first unit, it is possible to prevent the unit from becoming large and complicated.

  Further, the refrigerant flow path, which is the flow path of the cooling medium in the housing, is configured such that the cooling medium reaches the heat recovery device after reaching the thermoelectric power generator. The configuration of such a refrigerant flow path is not particularly limited as long as the cooling medium can reach the heat recovery device after reaching the thermoelectric generator. As a specific example of the coolant channel, for example, the cooling medium introduced into the housing is guided to the cooling medium channel (low heat source side) in the thermoelectric generator and then guided to the cooling medium channel in the heat recovery device. A pipe or the like configured to lead out the cooling medium from the housing after that can be cited (see FIG. 1 described later).

  Alternatively, the gap between the inner surface of the housing and the outer surface of the thermoelectric power generator and the heat recovery device and the gap between the outer surface of the thermoelectric power generation device and the outer surface of the heat recovery device are used as the refrigerant flow path, and the position close to the thermoelectric power generation device is set. The cooling medium may be introduced into the housing, and the cooling medium may be led out of the housing from a position close to the heat recovery device (see FIG. 2 described later).

  According to the above, since the cooling medium cooled by, for example, heat radiation in the radiator reaches the thermoelectric generator before the heat recovery device, it is possible to increase the temperature difference between the exhaust gas and the cooling medium in the thermoelectric generator. As a result, the power generation efficiency of the thermoelectric generator can be improved. In this way, the temperature of the cooling medium used for power generation in the thermoelectric power generation device rises to some extent, but in the heat recovery device that the cooling medium reaches after the thermoelectric power generation device, the very high temperature exhausted from the internal combustion engine Heat exchange is performed between the exhaust gas and the cooling medium. Therefore, since the temperature difference between the exhaust gas and the cooling medium in the heat recovery device is still large, a sufficiently large amount of heat can be applied from the exhaust gas to the cooling medium in the heat recovery device. That is, a sufficiently high heat recovery efficiency can be achieved in the heat recovery device.

  As described above, according to the first unit, it is possible to independently switch between execution and non-execution of heat exchange by the heat recovery device and thermoelectric conversion by the thermoelectric generator while reducing the size and complexity of the unit. it can.

  Here, the configuration of the first unit will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing one specific example of the configuration of the first unit. The first unit 101 shown in FIG. 1 is an integrated exhaust heat recovery unit including a thermoelectric power generation device 10 and a heat recovery device 20. The thermoelectric power generator 10 generates power by the temperature difference between the exhaust gas discharged from the internal combustion engine (not shown) and the cooling medium flowing into the internal combustion engine. The heat recovery device 20 applies the heat recovered from the exhaust gas discharged from the internal combustion engine to the cooling medium flowing into the internal combustion engine.

  In the first unit 101, the thermoelectric generator 10 and the heat recovery device 20 are housed in a common housing 30. Further, the thermoelectric generator 10 and the heat recovery device 20 are arranged in parallel with respect to the flow of exhaust gas. In the example shown in FIG. 1, an exhaust flow path 11 for supplying exhaust gas to the thermoelectric generator 10 and an exhaust flow path 21 for supplying exhaust gas to the heat recovery device 20 are arranged in parallel. In addition, in FIG. 1, the flow of the exhaust gas is shown by a white arrow.

  The coolant flow passage 31 that is a flow passage of the cooling medium in the housing 30 is represented by a hatched region. That is, the cooling flow path 31 in the housing 30 is configured such that the cooling medium reaches the heat recovery device 20 after reaching the thermoelectric generator 10. More specifically, as shown by the hatched arrow in FIG. 1, the cooling medium is introduced into the housing 30 from the lower part of the housing 30, and the thermoelectric conversion element 12 ( After passing through a space formed on the opposite side (low heat source side) from the exhaust flow passage 11 provided on the inner side (high heat source side) of the black-painted quadrangle), it is provided inside the heat recovery device 20. The exhaust gas passes through the space formed around the exhaust passage 21 and is led out of the housing 30 from the upper portion of the housing 30.

  In the example shown in FIG. 1, the cooling medium introduced into the housing 30 is supplied to the thermoelectric generator 10 by the cooling medium flow path (pipe) independently formed in the housing 30 as described above. After being guided, it is guided to the heat recovery device 20, and then guided from the housing 30.

  However, as in the first unit 102 shown in FIG. 2, a gap between the inner surface of the housing 30 and the outer surfaces of the thermoelectric power generator 10 and the heat recovery device 20, and the outer surface of the thermoelectric power generation device 10 and the outer surface of the heat recovery device 20. The space between them is used as a refrigerant flow path, the cooling medium is introduced into the housing 30 from a position close to the thermoelectric power generator 10, and the cooling medium is drawn out of the housing 30 from a position close to the heat recovery device 20. Good. In the example shown in FIG. 2, the exhaust flow passage 11, the thermoelectric conversion element 12, and a region including a void around the exhaust flow passage 11 (a region surrounded by a broken line) correspond to the thermoelectric power generation device 10, and the exhaust flow passage 21 and its surroundings. A region including a void (a region surrounded by a dotted line) corresponds to the heat recovery device 20.

  The above-described configuration shown in FIGS. 1 and 2 is merely a schematic illustration of the configuration of the first unit, and the configuration of the first unit such as the arrangement of each component and the flowing direction of the exhaust gas and the cooling medium is not shown. The details are not limited to these examples as long as the above-mentioned constituent requirements are satisfied.

  For example, in FIGS. 1 and 2 described above, for the purpose of facilitating the understanding of the present invention, the thermoelectric power generator 10 includes one exhaust passage 11 and the heat recovery unit 20 includes one exhaust passage 21. However, the thermoelectric power generator 10 and / or the heat recovery device 20 may include a plurality of exhaust passages. Also, regarding the number and arrangement of the thermoelectric conversion elements 12 in the thermoelectric power generator 10, various combinations can be adopted depending on the configuration of the thermoelectric power generator 10.

<< Second Embodiment >>
Hereinafter, an exhaust heat recovery unit according to the second embodiment of the present invention (hereinafter sometimes referred to as “second unit”) will be described.

  The second unit is configured so that the cooling medium is introduced into the housing from the lower side in the vertical direction and is drawn out from the upper side in the vertical direction in the housing in the posture when the exhaust heat recovery unit is in use. Is an exhaust heat recovery unit having the same configuration as the above-mentioned first unit, except that the above-mentioned first unit is configured. The "attitude of the exhaust heat recovery unit during use" as used herein means, for example, when the second unit is used for the purpose of recovering exhaust heat from the internal combustion engine mounted on the vehicle, the second unit is mounted on the vehicle. It means the posture (arranged state) of the second unit thus prepared.

  Due to the above, even when steam is generated from the cooling medium due to heat received by the thermoelectric generator and / or the heat recovery device, the steam is easily discharged from the upper side in the vertical direction to the outside of the housing. Therefore, it is possible to reduce the risk that the pressure of the vapor that has accumulated in the refrigerant flow channel excessively increases and may lead to problems such as damage to the cooling flow channel.

  Further, in the second unit, the thermoelectric generator is arranged on the lower side in the vertical direction, and the heat recovery device is arranged on the upper side in the vertical direction. On the other hand, as described above, the coolant flow path is configured such that the cooling medium is introduced into the housing from the lower side in the vertical direction and is led out from the upper side in the vertical direction. That is, also in the second unit, the cooling medium reaches the heat recovery device after reaching the thermoelectric generator.

  As described above, also in the second unit, similarly to the first unit, it is possible to enhance the power generation efficiency of the thermoelectric power generation device and achieve a sufficiently high heat recovery efficiency in the heat recovery device.

  As described in the description of the first unit 101, in the example shown in FIGS. 1 and 2, the cooling medium is introduced into the housing 30 from the lower side in the vertical direction and is led out from the upper side in the vertical direction. . Therefore, the configurations illustrated in FIGS. 1 and 2 satisfy the constituent requirements of the second unit.

<< Third Embodiment >>
Hereinafter, an exhaust heat recovery system according to the third embodiment of the present invention (hereinafter sometimes referred to as “third system”) will be described.

  The third system is an exhaust heat recovery system including an exhaust heat recovery unit according to the present invention (the present invention unit) including the first unit and the second unit described above, a switching mechanism, and a control device.

  The switching mechanism is a mechanism configured to switch the opening and closing of the flow path of the exhaust gas to the thermoelectric power generator and the heat recovery unit, which constitutes the exhaust heat recovery unit, independently of each other. The configuration of such a switching mechanism is not particularly limited as long as it is possible to switch the opening and closing of the exhaust gas supply flow path to the thermoelectric generator and the heat recovery device independently of each other. As a specific example of the switching mechanism, for example, a valve installed in the exhaust supply flow path to the thermoelectric power generation device and the heat recovery device and a branching part of the supply flow path to the thermoelectric generation device and the heat recovery device, respectively. The three-way valve etc. which were equipped can be mentioned. Further, these valves can be switched between open and closed by an actuator such as an electric motor, and the opening can be adjusted.

  The control device is configured to control the switching mechanism to switch the supply of exhaust gas to the thermoelectric generator and the heat recovery device. The configuration of such a control device is not particularly limited as long as it is possible to control the switching mechanism to switch the supply of exhaust gas to the thermoelectric power generator and the heat recovery device. As a specific example of the control device, for example, an electronic control circuit (ECU) having a microcomputer including a CPU, a ROM, a RAM, an interface and the like as a main component can be cited. The CPU executes the instructions (routine) stored in the memory (ROM) to control the switching mechanism according to the states of the internal combustion engine and the exhaust heat recovery unit to control the exhaust gas to the thermoelectric generator and the heat recovery unit. Switch supply.

  As described above, according to the third system, the heat exchange by the heat recovery unit and the thermoelectric conversion by the thermoelectric power generator are performed according to the states of the internal combustion engine and the exhaust heat recovery unit while reducing the size and complexity of the unit. The execution and non-execution of can be switched independently.

  Here, the configuration of the third system will be described with reference to the drawings. FIG. 3 is a schematic cross-sectional view showing one specific example of the configuration of the third system. A third system 301 shown in FIG. 3 is an exhaust heat recovery system including a first unit 101, a switching mechanism 40, and a control device (ECU) 50. The configuration of the first unit 101 has already been described above with reference to FIG. 1, and thus the description will not be repeated here.

  The switching mechanism 40 independently switches between opening and closing of a flow path for supplying exhaust gas to the thermoelectric generator 10 and the heat recovery device 20 that form the first unit 101. The switching mechanism 40 in the example shown in FIG. 3 is a rotary three-way type which is interposed in a branch portion of the exhaust gas supply flow path to the thermoelectric power generator 10 and the heat recovery device 20 to the thermoelectric power generation device 10 and the heat recovery device 20. It is configured as a valve. By rotating a rotor 41 (a black circle in which a flow passage portion is white) having an exhaust passage formed therein by an electric motor (not shown) as an actuator, the thermoelectric generator 10 and the heat recovery device It is possible to switch the opening and closing of the exhaust gas supply passage to the valve 20 independently of each other.

  Specifically, when the rotor 41 is in the state shown in FIG. 3A, since the exhaust supply flow path to both the thermoelectric generator 10 and the heat recovery device 20 is open, the thermoelectric generator 10 and Exhaust gas can be supplied to both of the heat recovery units 20. When the rotor 41 is in the state shown in (b), since only the exhaust gas supply path to the thermoelectric generator 10 is open, the exhaust can be supplied only to the thermoelectric generator 10. When the rotor 41 is in the state shown in (c), since only the exhaust gas supply passage to the heat recovery device 20 is open, the exhaust gas can be supplied only to the heat recovery device 20.

  Note that, as described above, the configuration of the switching mechanism 40 is not limited to the above, and as long as it is possible to independently switch the opening and closing of the exhaust supply flow path to the thermoelectric generator 10 and the heat recovery device 20, respectively. Not limited. For example, instead of the rotary type three-way valve as described above, a simple structure in which a partition plate-shaped valve element is rotated around a predetermined axis may be adopted. Alternatively, individual valves may be provided in the exhaust gas supply passages to the thermoelectric generator 10 and the heat recovery device 20, respectively. The valve system in this case is not particularly limited, and can be appropriately selected from various systems such as a sluice valve and a butterfly valve.

  The control device 50 controls the switching mechanism 40 to switch the supply of exhaust gas to the thermoelectric generator 10 and the heat recovery device 20. In the example shown in FIG. 3, the control device 50 controls power supply to an electric motor (not shown) as an actuator that rotates the rotor 41 to rotate the rotor 41 to a predetermined rotation position. It is possible to switch the opening and closing of the flow path of the exhaust gas to the thermoelectric generator 10 and the heat recovery device 20.

  Next, FIG. 4 is a schematic sectional view showing another specific example of the configuration of the third system. The third system 302 shown in FIG. 4 is an exhaust heat recovery system including the first unit 102, the switching mechanism 40, and the control device (ECU) 50. The configuration of the first unit 102 has already been described above with reference to FIG. 2, and thus the description will not be repeated here.

  In the third system 302, the switching mechanism 40 rotates around a predetermined axis in the branch portion of the exhaust gas supply flow path to the thermoelectric power generator 10 and the heat recovery device 20 to the thermoelectric power generation device 10 and the heat recovery device 20. A switching valve including a partition plate-shaped valve body 42 that is arranged as possible is adopted. By rotating the valve body 42 by an electric motor (not shown) as an actuator, the opening and closing of the exhaust flow passage to the thermoelectric power generator 10 and the heat recovery device 20 can be independently switched.

  Specifically, when the valve element 42 is in the state shown in FIG. 4A, the exhaust supply flow path to both the thermoelectric generator 10 and the heat recovery device 20 is open, so the thermoelectric generator 10 Exhaust gas can be supplied to both the heat recovery unit 20 and the heat recovery unit 20. When the valve body 42 is in the state shown in (b), since only the exhaust gas supply passage to the thermoelectric power generator 10 is open, the exhaust gas can be supplied only to the thermoelectric power generator 10. When the valve body 42 is in the state shown in (c), since only the exhaust gas supply passage to the heat recovery device 20 is open, the exhaust gas can be supplied only to the heat recovery device 20.

  The above-described configurations shown in FIGS. 3 and 4 are merely schematic exemplifications of the configuration of the third system, and are executed by the arrangement of each component, the exhaust and cooling medium flowing directions, and the control device. The details of the configuration and operation of the third system such as the specific contents of control are not limited to these examples as long as the above-described configuration requirements are satisfied.

<< 4th Embodiment >>
Hereinafter, an exhaust heat recovery system according to the fourth embodiment of the present invention (hereinafter, may be referred to as “fourth system”) will be described.

  As described above, according to the third system, the heat exchange by the heat recovery device and the thermoelectric conversion by the thermoelectric power generator are performed according to the states of the internal combustion engine and the exhaust heat recovery unit while reducing the size and complexity of the unit. The execution and non-execution of can be switched independently.

  The fourth system detects the state of the internal combustion engine and the exhaust heat recovery unit at each time by a predetermined detection means, and according to the result, the heat exchange by the heat recovery device and the thermoelectric conversion by the thermoelectric power generator are performed or not performed. And are automatically switched by the control device independently of each other.

  Specifically, the fourth system is an exhaust heat recovery system having the same configuration as the above-described third system, except that the fourth system further includes a temperature detection unit and a power detection unit. The temperature detecting means is configured to detect the refrigerant temperature, which is the temperature of the cooling medium flowing out from the internal combustion engine. The structure of such a temperature detecting means is not particularly limited as long as it can detect the refrigerant temperature. Specific examples of the temperature detecting means include a temperature sensor such as a thermistor. The temperature detecting means does not necessarily have to detect the refrigerant temperature itself, but may detect a temperature having a correlation with the refrigerant temperature and convert the detected temperature into the refrigerant temperature by the control device. Alternatively, the control described below may be executed based on the detected temperature.

  The electric power detection means is configured to detect generated electric power that is electric power generated by the thermoelectric generator. The configuration of such power detection means is not particularly limited as long as it is possible to detect the generated power. Specific examples of the electric power detection means include, for example, a combination of a voltage sensor that detects the output voltage of the thermoelectric generator and a current sensor that detects the output current. According to this, the power generation can be calculated by the control device based on the detected output voltage and output current.

  Further, in the fourth system, the control device is configured to execute the controls shown in (1) to (4) listed below.

  (1) When it is determined that the refrigerant temperature is lower than the predetermined lower limit temperature, the switching mechanism is controlled to open the exhaust gas supply passage to the heat recovery device. As the “predetermined lower limit temperature” here, for example, the lowest temperature of the refrigerant temperature that is determined to be unnecessary for warming up the internal combustion engine can be adopted. In other words, it is possible to set the refrigerant temperature corresponding to the lowest temperature of the internal combustion engine that can achieve good operating efficiency, as the predetermined lower limit temperature. When the refrigerant temperature does not reach such a lower limit temperature (that is, the refrigerant temperature is lower than the lower limit temperature), it is desirable to increase the refrigerant temperature by performing heat exchange (heat recovery) by the heat recovery device. Therefore, the control device controls the switching mechanism to open the exhaust gas supply path to the heat recovery device, and performs heat exchange by the heat recovery device.

  (2) When it is determined that the refrigerant temperature is equal to or higher than the predetermined upper limit temperature, the switching mechanism is controlled to close the exhaust supply passage to the heat recovery device and to close the exhaust supply passage to the thermoelectric generator. open. As the "predetermined upper limit temperature" here, for example, it is determined that it is difficult to sufficiently lower the temperature of the cooling medium due to heat dissipation in the radiator and it may be difficult to sufficiently cool the internal combustion engine. The lowest temperature of the cooling medium (for example, 80 ° C.) can be adopted. When the refrigerant temperature reaches such an upper limit temperature (that is, the refrigerant temperature is equal to or higher than the upper limit temperature), heat exchange (heat recovery) by the heat recovery device is stopped to reduce a further increase in the refrigerant temperature. Is desirable.

  Therefore, the control device controls the switching mechanism to close the exhaust flow path to the heat recovery device. At this time, if the exhaust gas supply passage to the thermoelectric generator is closed, the exhaust gas exhaust path discharged from the internal combustion engine is blocked. Therefore, the control device controls the switching mechanism to open the exhaust gas supply passage to the thermoelectric generator. As a matter of course, if the exhaust gas supply passage to the thermoelectric generator is already open at this time, it is not necessary to open the exhaust supply passage to the thermoelectric generator again by the control device.

  (3) When it is determined that the temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generator is less than the predetermined upper limit temperature difference based on the refrigerant temperature and the generated electric power, the switching mechanism is controlled to transfer to the thermoelectric power generator. Open the exhaust flow path. The “temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generator” can be calculated by the control device based on the refrigerant temperature and the generated power. Specifically, for example, an experimental thermoelectric generator is provided with a detection means for detecting a temperature difference between the high heat source side and the low heat source side of the thermoelectric conversion element that constitutes the thermoelectric generator, and the thermoelectric generator is prepared. Correspondence between the temperature difference and the generated power is obtained in advance at various refrigerant temperatures by using a device. Then, when the actual control is executed, the temperature difference can be specified based on the correspondence relationship from the refrigerant temperature detected by the temperature detecting unit and the generated power detected by the power detecting unit.

  In addition, as the "predetermined upper limit temperature difference" referred to here, for example, with the high heat source side of the thermoelectric conversion element that is caused by the temperature difference between the high heat source side and the low heat source side of the thermoelectric conversion element that constitutes the thermoelectric power generator. It is possible to adopt the minimum value of the above-mentioned temperature difference in which the thermoelectric conversion element is damaged due to a difference in the amount of thermal deformation between the low heat source side and the like. Such a minimum value can be obtained in advance by a preliminary experiment or the like using the thermoelectric generator that constitutes the fourth system.

  When the temperature difference does not reach such an upper limit temperature difference (that is, the temperature difference is less than a predetermined upper limit temperature difference), the thermoelectric conversion as described above is performed even if thermoelectric conversion is performed by the thermoelectric generator. It is unlikely that element damage will occur. Therefore, in this case, from the viewpoint of energy saving, it is desirable to carry out thermoelectric conversion by the thermoelectric generator. Therefore, the control device controls the switching mechanism to open the exhaust gas supply path to the thermoelectric power generation device, and performs thermoelectric conversion by the thermoelectric power generation device.

  (4) When it is determined that the temperature difference is equal to or more than the upper limit temperature difference, the switching mechanism is controlled to close the exhaust supply flow path to the thermoelectric generator and the exhaust supply flow path to the heat recovery device. open. When the temperature difference reaches the upper limit temperature difference (that is, the temperature difference is equal to or more than the upper limit temperature difference), when the exhaust gas is supplied or continuously supplied to the thermoelectric generator, the thermoelectric conversion element as described above is provided. There is a high possibility that damage will occur. Therefore, in this case, it is desirable to stop the supply of the exhaust gas to the thermoelectric generator to reduce the further increase in the temperature difference.

  Therefore, the control device controls the switching mechanism to close the exhaust supply flow path to the thermoelectric generator. At this time, if the exhaust flow path to the heat recovery unit is closed, the exhaust path of the exhaust gas discharged from the internal combustion engine will be blocked. Therefore, the control device controls the switching mechanism to open the exhaust gas supply passage to the heat recovery device. Of course, at this time, if the exhaust gas supply path to the heat recovery device is already open, it is not necessary to open the exhaust gas supply path to the heat recovery device again by the control device.

  As described above, according to the fourth system, the states of the internal combustion engine and the exhaust heat recovery unit at each time are detected by the predetermined detection means, and according to the result, the heat exchange by the heat recovery device and the thermoelectric generator are performed. Whether the thermoelectric conversion is performed or not can be automatically and independently switched by the control device.

  Here, the configuration of the fourth system will be described with reference to the drawings. FIG. 5 is a schematic cross-sectional view showing one specific example of the configuration of the fourth system. The fourth system 401 shown in FIG. 5 further includes a temperature detection unit 51 and an electric power detection unit 52, and performs thermoelectric conversion by the thermoelectric power generator 10 and heat exchange by the heat recovery unit 20 according to the detection results by these detection units. It has the same configuration as the third system 301 described above with reference to FIG. 3, except that the control device 50 is configured to automatically and independently switch implementation and non-implementation. Therefore, in the following description, the fourth system 401 will be described by focusing on the difference from the third system 301.

  The temperature detecting means 51 is configured to detect the refrigerant temperature, which is the temperature of the cooling medium flowing out from the internal combustion engine (not shown). The power detection means 52 is configured to detect the generated power, which is the power generated by the thermoelectric power generator 10. The control device 50 controls the switching mechanism 40 to execute the above-described controls (1) to (4). Specifically, the control device 50 controls an electric motor (not shown) as an actuator of a rotary type three-way valve which is interposed in a branch portion of a flow path for supplying exhaust gas to the thermoelectric generator 10 and the heat recovery device 20. Then, by rotating the rotor 41, the controls listed in (1 ′) to (4 ′) below are executed.

(1 ′) When it is determined that the refrigerant temperature is lower than the predetermined lower limit temperature, the switching mechanism 40 is controlled to open the exhaust gas supply passage to the heat recovery device 20 ((a) in FIG. See c)).
(2 ′) When it is determined that the refrigerant temperature is equal to or higher than the predetermined upper limit temperature, the switching mechanism 40 is controlled to close the exhaust gas supply path to the heat recovery device 20 and exhaust gas to the thermoelectric power generator 10. The supply flow path is opened (see FIG. 5B).
(3 ′) When it is determined that the temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generator 10 is less than the predetermined upper limit temperature difference based on the refrigerant temperature and the generated power, the switching mechanism 40 is controlled to control the thermoelectric power generation. An exhaust gas supply channel to the device 10 is opened (see (a) or (b) of FIG. 5).
(4 ′) When it is determined that the temperature difference is equal to or more than the upper limit temperature difference, the switching mechanism 40 is controlled to close the exhaust supply flow path to the thermoelectric generator 10 and supply the exhaust to the heat recovery device 20. The flow channel is opened (see (c) of FIG. 5).

  When the rotor 41 is in the state shown in FIG. 5D, that is, when both the exhaust gas supply passage to the thermoelectric generator 10 and the exhaust gas supply passage to the heat recovery device 20 are closed, The exhaust path of the exhaust gas discharged from the internal combustion engine is blocked. Therefore, the control device 50 controls the switching mechanism 40 so that the rotor 41 does not reach the state shown in FIG. 5D as shown in (1 ') to (4') above.

  Next, FIG. 6 is a schematic cross-sectional view showing another specific example of the configuration of the fourth system. The fourth system 402 shown in FIG. 6 further includes a temperature detecting unit 51 and a power detecting unit 52, and performs thermoelectric conversion by the thermoelectric power generator 10 and heat exchange by the heat recovery unit 20 according to the detection results by these detecting units. It has the same configuration as the third system 302 described above with reference to FIG. 4, except that the control device 50 is configured to automatically and independently switch between execution and non-execution. Further, the control executed by the control device 50 included in the fourth system 402 is the same as the control listed in (1) to (4) and (1 ') to (4') described above. Therefore, the description of the configuration of the fourth system 402 and the control executed by the control device 50 included in the fourth system 402 will be omitted.

  In the fourth system 402, similar to the third system 302, the switching mechanism 40 can rotate around a predetermined axis in the branch portion of the exhaust flow passage to the thermoelectric power generator 10 and the heat recovery device 20. A switching valve having a partition plate-shaped valve element 42 arranged in the above is adopted. Therefore, unlike the fourth system 401, both the exhaust flow passage to the thermoelectric generator 10 and the exhaust flow passage to the heat recovery device 20 are closed, and the exhaust gas discharged from the internal combustion engine is discharged. There is no risk that the route will be blocked.

  The configurations shown in FIGS. 5 and 6 described above are merely schematic exemplifications of the configuration of the fourth system, and are executed by the arrangement of the respective components, the flow directions of the exhaust gas and the cooling medium, and the control device. The details of the configuration and operation of the fourth system, such as specific control contents, are not limited to these examples as long as the above-described configuration requirements are satisfied.

<< Fifth Embodiment >>
Hereinafter, the exhaust heat recovery system according to the fifth embodiment of the present invention (hereinafter, may be referred to as “fifth system”) will be described.

  As described above, when it is determined that the refrigerant temperature is equal to or higher than the predetermined upper limit temperature, it is desirable to close the exhaust gas supply passage to the heat recovery device and stop the exhaust gas supply to the heat recovery device. Further, when it is determined that the temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generation device is equal to or more than a predetermined upper limit temperature difference, the exhaust flow path to the thermoelectric power generation device is closed to close the exhaust gas to the thermoelectric power generation device. It is desirable to stop the supply.

  Therefore, when the refrigerant temperature is equal to or higher than the predetermined upper limit temperature and the temperature difference between the exhaust gas and the cooling medium in the thermoelectric generator is equal to or higher than the predetermined upper limit temperature difference, the supply flow of the exhaust gas to the heat recovery device It is desirable to close both the path and the exhaust flow path to the thermoelectric generator. However, in the above-described third system and fourth system, when both the exhaust supply passage to the heat recovery device and the exhaust supply passage to the thermoelectric generator are closed, the exhaust passage of the exhaust gas discharged from the internal combustion engine becomes It will be cut off.

  Therefore, in the fifth system, a bypass flow passage, which is a flow passage for exhaust gas that does not pass through the exhaust heat recovery unit, is further provided, and the switching mechanism is controlled to control the flow of exhaust gas to the thermoelectric generator, the heat recovery device, and the bypass flow passage. An exhaust heat recovery system having the same configuration as the above-described third system, except that the control device is configured to switch the supply.

  Specifically, the fifth system further includes a bypass passage that is an exhaust passage that does not pass through the exhaust heat recovery unit according to the present invention (the present invention unit). Such a bypass flow path is an exhaust flow path capable of discharging exhaust gas without substantially exchanging heat with the thermoelectric generator and the heat recovery device included in the unit of the present invention included in the fifth system. As long as it exists, it is not particularly limited.

  Further, in the fifth system, the switching mechanism is configured so as to switch the opening / closing of the thermoelectric generator and the heat recovery unit constituting the exhaust heat recovery unit and the exhaust supply flow path to the bypass flow path, independently of each other. . The configuration of such a switching mechanism is such that the opening and closing of the exhaust supply passage to the thermoelectric generator, the exhaust supply passage to the heat recovery device, and the exhaust supply passage to the bypass passage are independently switched. There is no particular limitation as long as it is possible. As a specific example of the switching mechanism, as described above with respect to the third system, for example, the valves installed in the thermoelectric generator, the heat recovery device, and the exhaust supply passage to the bypass passage, and the supply passage Examples thereof include a thermoelectric power generator, a heat recovery device, and a four-way valve interposed at a branch portion to a bypass flow path. Further, these valves can be switched between open and closed by an actuator such as an electric motor, and the opening can be adjusted.

  In addition, the control device is configured to control the switching mechanism to switch the supply of exhaust gas to the thermoelectric power generator, the heat recovery device, and the bypass passage. The configuration of such a control device is not particularly limited as long as the switching mechanism can be controlled to switch the supply of exhaust gas to the thermoelectric power generator, the heat recovery device, and the bypass flow passage. Specific examples of the control device include the electronic control circuit (ECU) as described above. The CPU that constitutes the ECU controls the switching mechanism according to the states of the internal combustion engine and the exhaust heat recovery unit by executing the instructions (routine) stored in the memory (ROM), and the thermoelectric generator and the heat recovery unit. Switch the exhaust supply to.

  As described above, according to the fifth system, the heat exchange by the heat recovery unit and the thermoelectric conversion by the thermoelectric power generator are performed according to the states of the internal combustion engine and the exhaust heat recovery unit while reducing the size and complexity of the unit. The execution and non-execution of can be switched independently. In addition, according to the fifth system, in the case where it is determined that the refrigerant temperature is equal to or higher than the predetermined upper limit temperature and the temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generator is equal to or higher than the predetermined upper limit temperature difference, Even if both the exhaust supply passage to the collector and the exhaust supply passage to the thermoelectric generator are closed, the exhaust passage of the exhaust exhausted from the internal combustion engine can be secured by the bypass passage.

  Here, the configuration of the fifth system will be described with reference to the drawings. FIG. 7 is a schematic cross-sectional view showing one specific example of the configuration of the fifth system. The fifth system 501 shown in FIG. 7 has the same configuration as the third system 301 described above with reference to FIG. 3 except for the following points.

  The fifth system 501 further includes a bypass flow passage 60 that is a flow passage for exhaust gas that does not pass through the first unit 101. In the example shown in FIG. 7, the bypass flow passage 60 is an exhaust pipe in which a flow passage through which exhaust gas discharged from an internal combustion engine (not shown) flows is formed. The exhaust flow passage 11 for supplying exhaust gas to the thermoelectric generator 10, the exhaust flow passage 21 for supplying exhaust gas to the heat recovery device 20, and the bypass flow passage 60 are arranged in parallel with each other. In FIG. 7 as well, the flow of exhaust gas is shown by the white arrows.

  Furthermore, in the fifth system 501, the switching mechanism 40 is configured so as to switch the opening / closing of the exhaust flow passage to the thermoelectric power generator 10 and the heat recovery device 20 and the bypass flow passage 60, which configure the first unit 101, independently of each other. Is formed (area shown as a circle with a grid). Although a specific configuration of the switching mechanism 40 is omitted in FIG. 7, a specific example of the configuration of the switching mechanism 40 will be described in detail in an embodiment described later.

  In addition, in the fifth system 501, the control device 50 is configured to control the switching mechanism 40 to switch the supply of exhaust gas to the thermoelectric power generator 10, the heat recovery device 20, and the bypass flow passage 60. In the example shown in FIG. 7, the control device 50 controls power supply to an electric motor (not shown) as an actuator that rotates a valve body (not shown) that configures the switching mechanism 40 to perform thermoelectric generation. It is possible to switch the opening and closing of the exhaust gas supply flow path to the device 10, the heat recovery device 20, and the bypass flow path 60.

  Next, FIG. 8 is a schematic sectional view showing another specific example of the configuration of the fifth system. A fifth system 502 shown in FIG. 8 has the same configuration as the fifth system 501 described above with reference to FIG. 7, except that the first unit 102 is provided instead of the first unit 101. Therefore, the detailed description of the fifth system 502 will be omitted.

  The above-described configurations shown in FIGS. 7 and 8 are merely schematic examples of the configuration of the fifth system, and are executed by the arrangement of each component, the exhaust and cooling medium flowing directions, and the control device. The details of the configuration and operation of the fifth system, such as the specific contents of control, are not limited to these examples as long as the above configuration requirements are satisfied.

<< 6th Embodiment >>
Hereinafter, an exhaust heat recovery system according to the sixth embodiment of the present invention (hereinafter sometimes referred to as “sixth system”) will be described.

  As described above, according to the fifth system, the heat exchange by the heat recovery unit and the thermoelectric conversion by the thermoelectric power generator are performed according to the states of the internal combustion engine and the exhaust heat recovery unit while reducing the size and complexity of the unit. The execution and non-execution of can be switched independently. In addition, according to the fifth system, in the case where it is determined that the refrigerant temperature is equal to or higher than the predetermined upper limit temperature and the temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generator is equal to or higher than the predetermined upper limit temperature difference, Even if both the exhaust supply passage to the collector and the exhaust supply passage to the thermoelectric generator are closed, the exhaust passage of the exhaust exhausted from the internal combustion engine can be secured by the bypass passage.

  The sixth system detects the states of the internal combustion engine and the exhaust heat recovery unit at each time by a predetermined detection means, and according to the result, the heat exchange by the heat recovery device and the thermoelectric conversion by the thermoelectric power generator are performed or not performed. And are automatically switched by the control device independently of each other. Further, when the sixth system closes both the exhaust flow passage to the heat recovery device and the exhaust flow passage to the thermoelectric generator, the sixth system automatically exhausts the exhaust gas from the internal combustion engine. Is configured to be secured by the bypass flow path.

  Specifically, the sixth system is an exhaust heat recovery system having the same configuration as the above-described fifth system, except that the sixth system further includes a temperature detection unit and a power detection unit. The temperature detecting means is configured to detect the refrigerant temperature, which is the temperature of the cooling medium flowing out from the internal combustion engine. The electric power detection means is configured to detect generated electric power that is electric power generated by the thermoelectric generator. The configurations of the temperature detecting means and the electric power detecting means have been already described in the above description of the third system, and therefore the description thereof will be omitted.

  Further, in the sixth system, the control device is configured to execute the controls shown in (5) to (9) listed below.

  (5) When it is determined that the refrigerant temperature is lower than the predetermined lower limit temperature, the switching mechanism is controlled to open the exhaust flow passage to the heat recovery device. The “predetermined lower limit temperature” mentioned here has already been described in the description of the fourth system, and therefore the description thereof will be omitted. As described above, when the refrigerant temperature does not reach the lower limit temperature (that is, the refrigerant temperature is lower than the lower limit temperature), it is desirable to increase the refrigerant temperature by performing heat exchange (heat recovery) by the heat recovery device. . Therefore, the control device controls the switching mechanism to open the exhaust gas supply path to the heat recovery device, and performs heat exchange by the heat recovery device.

  (6) When it is determined that the refrigerant temperature is equal to or higher than the predetermined upper limit temperature, the switching mechanism is controlled to close the exhaust supply flow path to the heat recovery device. The “predetermined upper limit temperature” mentioned here has already been described in the description of the fourth system, and thus the description thereof will be omitted. When the refrigerant temperature reaches the upper limit temperature (that is, the refrigerant temperature is equal to or higher than the upper limit temperature), it is desirable to stop the heat exchange (heat recovery) by the heat recovery device to reduce a further increase in the refrigerant temperature. . Therefore, the control device controls the switching mechanism to close the exhaust flow path to the heat recovery device.

  (7) When it is determined that the temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generator is less than the predetermined upper limit temperature difference based on the refrigerant temperature and the generated electric power, the switching mechanism is controlled to transfer to the thermoelectric power generator. Open the exhaust flow path. The "temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generator" and the "predetermined upper limit temperature difference" have already been described in the description of the fourth system, and therefore the description thereof is omitted here. When the temperature difference does not reach the upper limit temperature difference (that is, the temperature difference is less than a predetermined upper limit temperature difference), even if thermoelectric conversion is performed by the thermoelectric generator, the thermoelectric conversion element is damaged as described above. Is unlikely to occur. Therefore, in this case, from the viewpoint of energy saving, it is desirable to carry out thermoelectric conversion by the thermoelectric generator. Therefore, the control device controls the switching mechanism to open the exhaust gas supply path to the thermoelectric power generation device, and performs thermoelectric conversion by the thermoelectric power generation device.

  (8) When it is determined that the temperature difference is equal to or more than the upper limit temperature difference, the switching mechanism is controlled to close the exhaust supply flow path to the thermoelectric generator. When the temperature difference reaches the upper limit temperature difference (that is, the temperature difference is equal to or more than the upper limit temperature difference), when the exhaust gas is supplied to the thermoelectric power generator or continued, the thermoelectric conversion element as described above is provided. There is a high possibility that damage will occur. Therefore, in this case, it is desirable to stop the supply of the exhaust gas to the thermoelectric generator to reduce the further increase in the temperature difference. Therefore, the control device controls the switching mechanism to close the exhaust supply flow path to the thermoelectric generator.

  (9) When simultaneously closing both the exhaust gas supply passage to the heat recovery device and the exhaust gas supply passage to the thermoelectric generator, the switching mechanism is controlled to open the exhaust gas supply passage to the bypass passage. . As a matter of course, if all the exhaust flow paths of the exhaust gas discharged from the internal combustion engine are cut off, the operation of the internal combustion engine cannot be continued. Therefore, the control device simultaneously closes both the exhaust gas supply passage to the heat recovery device and the exhaust gas supply passage to the thermoelectric generator as a result of the controls listed in (5) to (8) above. In this case, the exhaust gas supply channel to the bypass channel is opened. Needless to say, at this time, if the exhaust gas supply passage to the bypass passage has already been opened, it is not necessary to open the exhaust gas supply passage to the bypass passage again by the control device.

  By the control shown in the above (9), as a result of the controls listed in the above (5) to (8), both the exhaust supply flow path to the heat recovery device and the exhaust supply flow path to the thermoelectric generator are simultaneously formed. Even when it is closed, the exhaust passage of the exhaust gas discharged from the internal combustion engine can be secured by the bypass passage.

  As described above, according to the sixth system, the states of the internal combustion engine and the exhaust heat recovery unit at each time are detected by the predetermined detection means, and according to the result, the heat exchange by the heat recovery device and the thermoelectric generator are performed. Whether the thermoelectric conversion is performed or not can be automatically and independently switched by the control device.

  In addition to the above, according to the sixth system, when it is determined that the refrigerant temperature is equal to or higher than a predetermined upper limit temperature and the temperature difference between the exhaust gas and the cooling medium in the thermoelectric generator is equal to or higher than the predetermined upper limit temperature difference, etc. Even if both the exhaust flow path to the heat recovery device and the exhaust flow path to the thermoelectric generator are closed in the above, the control device automatically bypasses the exhaust path of the exhaust gas discharged from the internal combustion engine. Can be secured by.

  Here, the configuration of the sixth system will be described with reference to the drawings. FIG. 9 is a schematic cross-sectional view showing one specific example of the configuration of the sixth system. The sixth system 601 shown in FIG. 9 has the same configuration as the fifth system 501 described above with reference to FIG. 7, except for the points listed in (A) to (C) below.

  (A) A temperature detecting means 51 and a power detecting means 52 are further provided. As described above in the description of the fifth system 501, the temperature detecting means 51 is configured to detect the refrigerant temperature, which is the temperature of the cooling medium flowing out from the internal combustion engine (not shown). Further, the power detection unit 52 is configured to detect the generated power, which is the power generated by the thermoelectric power generator 10.

  (B) A control device for automatically and independently switching between execution and non-execution of thermoelectric conversion by the thermoelectric power generator 10 and heat exchange by the heat recovery device 20 according to the detection results of the temperature detection means 51 and the power detection means 52. 50 are configured. Specifically, the control device 50 executes the controls listed in (5) to (8) described above.

  (C) When closing both the exhaust gas supply passage to the thermoelectric generator 10 and the exhaust gas supply passage to the heat recovery device 20, the exhaust gas supply passage to the bypass flow passage 60 is automatically opened. The control device 50 is configured in the. Specifically, the control device 50 executes the control described in (9) above.

  Next, FIG. 10 is a schematic sectional view showing another specific example of the configuration of the sixth system. The sixth system 602 illustrated in FIG. 10 has the same configuration as the sixth system 601 described above with reference to FIG. 9 except that the first unit 102 is provided instead of the first unit 101. Therefore, the detailed description of the sixth system 602 will be omitted.

  Note that the above-described configurations shown in FIGS. 9 and 10 are merely schematic examples of the configuration of the sixth system, and are executed by the arrangement of each component, the exhaust gas and cooling medium flowing directions, and the control device. Details of the configuration and operation of the sixth system, such as specific control contents, are not limited to these examples as long as the above-described configuration requirements are satisfied.

  Although the exhaust heat recovery unit and the exhaust heat recovery system according to various embodiments of the present invention have been described above, the exhaust heat recovery unit according to the representative embodiment of the present invention will be described below with reference to the drawings. The details will be described.

〔Constitution〕
FIG. 11 shows an exhaust heat recovery unit according to the first embodiment of the present invention (hereinafter, referred to as a “first embodiment unit 101e”) in a posture in use (for example, a posture when mounted on a vehicle). 3 is a top view (plan view) of FIG. The first embodiment unit 101e is an exhaust heat recovery unit corresponding to the above-described first unit 101 and / or 102.

  The thermoelectric generator 10, the heat recovery unit 20, and the cooling medium flow passage 31, which is a passage for the cooling medium, which constitute the unit 101e of the first embodiment, are housed in the housing 30. In FIG. 11, the exhaust gas is introduced from the left side toward the paper surface of the first embodiment unit 101e and discharged to the right side (see the white arrow). The cooling medium is introduced into the housing 30 from the refrigerant passage introducing portion 31a provided on the lower right side of the drawing of the first embodiment unit 101e, and the refrigerant passage deriving portion 31b provided on the upper left side. It is discharged from the inside of the housing 30 to the upper side through (see the hatched arrow).

  FIG. 12 is a front view of the first embodiment unit 101e as viewed from the upstream side of the flow of exhaust gas. The cooling medium is introduced into the housing 30 from a coolant passage introducing portion 31a provided on the lower right side of the drawing of the housing 30, and is passed through the coolant passage leading portion 31b provided on the upper left side of the housing. It is discharged from inside 30 to the upper side (see the hatched arrow). The exhaust gas is introduced into the high heat source side of the thermoelectric generator 10 by the exhaust flow path 11 and / or introduced into the high heat source side of the heat recovery device 20 by the exhaust flow path 21. In the example shown in FIG. 12, corrugated plate-shaped fins 11f and 21f are formed inside the exhaust passages 11 and 21, respectively, for the purpose of increasing the efficiency of receiving heat from the exhaust.

  FIG. 13 is a side view of the first embodiment unit 101e as viewed from the right side (that is, in the direction of arrow A shown in FIG. 11) with respect to the flow of exhaust gas. However, FIG. 13 shows a state in which the housing 30 of the first embodiment unit 101e is cut out by the plane including the line AA shown in FIG.

  As shown in FIG. 13, the thermoelectric generator 10 is arranged on the lower side of the paper surface, and the heat recovery unit 20 is arranged on the upper side of the paper surface, and they are housed in a common housing 30. The thermoelectric generator 10 shown in FIG. 13 is composed of three cases 13, and an exhaust passage 11 and a thermoelectric conversion element 12 (not shown) are housed inside each case 13. That is, the thermoelectric power generation device 10 includes three systems of thermoelectric power generation units. The heat recovery device 20 is composed of two cases 23, and an exhaust passage 21 is housed inside each case 23. That is, the heat recovery device 20 includes two systems of heat recovery units. The case 23 and the exhaust passage 21 do not necessarily have to be separate members, and the exhaust passage 21 may also serve as the case 23. That is, the exhaust passage 21 and the case 23 may be integrally formed.

  FIG. 14 is a sectional view of the first embodiment unit 101e taken along a plane including the line AA shown in FIG. As shown in (a), the first embodiment unit 101e includes a thermoelectric generator 10 including three thermoelectric generators 10p and a heat recovery unit 20 including two heat recovery units 20p. There is. Moreover, as shown in (b), each thermoelectric power generation unit 10 p includes an exhaust flow path 11 and a thermoelectric conversion element 12 that are housed inside a case 13. Further, as shown in (c), each heat recovery unit 20p includes an exhaust passage 21 housed inside a case 23.

  Dimples 13d and 23d protruding outward are formed on the surfaces of the case 13 and the case 23 by embossing, respectively. The first embodiment unit 101e is configured by stacking three thermoelectric generators 10p and two heat recovery units 20p. In this state, the dimples come into contact with each other to form a space between adjacent cases. In the first embodiment unit 101e, the coolant passage 31 is formed by the gap. Further, the refrigerant flow path 31 configured in this manner communicates with the inside of the housing 30.

  The measures for forming the gap between the adjacent cases are not limited to the above, and for example, the dimples may be formed by attaching a separate member to the surface of the case, or between the adjacent cases. You may interpose a spacer in.

〔effect〕
According to the first embodiment unit 101e, the thermoelectric power generation device 10 is assembled by interposing the thermoelectric conversion element 12 between the exhaust flow passage 11 that is a high heat source and the refrigerant flow passage 31 that is a low heat source according to the above configuration. As a result, efficient thermoelectric power generation can be realized. On the other hand, in the heat recovery device 20, the exhaust flow passages 21 and the refrigerant flow passages 31 are alternately formed adjacent to each other, so that the heat exchange efficiency between the exhaust gas and the cooling medium is increased, and the heat recovery is performed efficiently. Can be realized.

  Further, since the thermoelectric power generator 10 and the heat recovery device 20 are arranged in parallel, it is possible to reduce the size and complexity of the unit and to shorten the total length of the exhaust passage, so that the exhaust gas The pressure loss can be reduced. Further, by providing the switching mechanism as described above on the upstream side of the first embodiment unit 101e, the heat exchange (warming up) by the heat recovery unit and the thermoelectric conversion (power generation) by the thermoelectric generator can be performed or not performed. Each can be switched independently.

  In addition, in the first embodiment unit 101e, in the housing 30 in the posture during use, the cooling medium is introduced into the housing 30 from below in the vertical direction, and is drawn out from above in the vertical direction. The coolant channel 31 is configured. On the other hand, in the housing 30, the thermoelectric generator 10 is arranged on the lower side in the vertical direction, and the heat recovery unit 20 is arranged on the upper side in the vertical direction. As a result, the cooling medium reaches the thermoelectric power generator 10 before the heat recovery device 20, so that the power generation efficiency of the thermoelectric power generator 10 can be increased. After that, the cooling medium heated to some extent reaches the heat recovery device 20, but since the temperature difference between the exhaust gas and the cooling medium in the heat recovery device 20 is still large, the heat recovery efficiency of the heat recovery device 20 is sufficiently high. Can be achieved.

  Next, an exhaust heat recovery system according to another exemplary embodiment of the present invention will be described in detail below with reference to the drawings.

〔Constitution〕
FIG. 15 is a diagram showing an exhaust heat recovery system according to a second embodiment of the present invention (hereinafter, referred to as a “second embodiment system 301e”) in a posture in use (for example, a posture when mounted on a vehicle). FIG. The second embodiment system 301e is an exhaust heat recovery system corresponding to the third system 301 and / or 302 described above.

  The second embodiment system 301e is an exhaust heat recovery system including the above-described first embodiment unit 101e, the switching mechanism 40, and the control device 50. The switching mechanism 40 in the system 301e of the second embodiment is similar to the above-described third system 302 in that the flow path of the exhaust gas to the thermoelectric power generator 10 and the heat recovery device 20 is connected to the thermoelectric power generation device 10 and the heat recovery device 20. A partition plate-shaped valve element 42 is provided at the branching portion so as to be rotatable around a predetermined axis. As described above, the control device (ECU) 50 controls the electric motor (not shown) as an actuator to rotate the valve body 42, thereby supplying the exhaust gas to the thermoelectric generator 10 and the heat recovery device 20. The opening and closing of can be switched independently of each other.

  For example, when it is determined that the temperature of the refrigerant is lower than a predetermined lower limit temperature during warm start of the internal combustion engine or the like, and it is necessary to warm up the internal combustion engine, exhaust to the thermoelectric generator 10 as shown in FIG. The valve body 42 is rotated so as to close the supply flow path of. This makes it possible to supply the exhaust gas only to the heat recovery unit 20 and preferentially perform the transfer (heat reception) of the heat from the exhaust gas to the cooling medium.

  Further, when the thermoelectric conversion by the thermoelectric power generator 10 and the heat exchange by the heat recovery device 20 are performed in parallel, the exhaust gas supply flow to both the thermoelectric power generation device 10 and the heat recovery device 20 as shown in FIG. The valve body 42 is rotated so as to open the passage. As a result, exhaust gas can be supplied to both the thermoelectric power generator 10 and the heat recovery device 20, and thermoelectric conversion by the thermoelectric power generation device 10 and heat exchange by the heat recovery device 20 can be performed in parallel.

  Further, for example, when the internal combustion engine is sufficiently warmed up and the refrigerant temperature is equal to or higher than a predetermined lower limit temperature and the thermoelectric conversion by the thermoelectric generator 10 is to be intensively performed, and when the refrigerant temperature is equal to or higher than the predetermined upper limit temperature, the refrigerant temperature When it is desired to avoid a further rise of the valve body 42, the valve body 42 is rotated so as to close the exhaust gas supply passage to the heat recovery device 20, as shown in FIG. As a result, the exhaust gas can be supplied only to the thermoelectric power generator 10, and the thermoelectric conversion (power generation) by the thermoelectric power generator 10 can be preferentially performed.

〔effect〕
As described above, according to the system 301e of the second embodiment, the heat exchange and the thermoelectric generator using the heat recovery device are performed according to the states of the internal combustion engine and the exhaust heat recovery unit while reducing the size and complexity of the unit. Execution and non-execution of thermoelectric conversion can be independently switched. The control device 50 may automatically switch between heat exchange by the heat recovery device and thermoelectric conversion by the thermoelectric power generator according to a predetermined condition as in the above-described fourth system. .

[Modification of Embodiment 2]
The second embodiment system 301e is configured such that the heat exchange by the heat recovery unit and the thermoelectric conversion by the thermoelectric generator can be independently switched. However, the thermoelectric conversion by the thermoelectric generator may always be carried out, and the heat recovery by the heat recovery device may be switched to be carried out or not carried out. Therefore, an exhaust heat recovery system according to a modified example of the second embodiment of the present invention (hereinafter, referred to as a “second embodiment system 302e”) will be described in detail below with reference to the drawings. .

〔Constitution〕
FIG. 18 is a cross-sectional view of the system of the second embodiment 302e in a posture during use. As shown in FIG. 18, the system 302e of the second embodiment is described above except that the switching mechanism 40 is configured such that the valve body 42 cannot close the supply flow path of the exhaust gas to the thermoelectric generator 10. It has the same configuration as the second embodiment system 301e described above.

  For example, when the internal combustion engine is cold-started or the like, and the refrigerant temperature is below the predetermined lower limit temperature, and it is determined that the internal combustion engine needs to be warmed up, the switching mechanism 40 causes the heat recovery device to operate as shown in FIG. It is possible to open the supply passage of the exhaust gas to 20 and perform the thermoelectric conversion by the thermoelectric power generation device 10 and the heat exchange by the heat recovery device 20 in parallel.

  On the other hand, for example, when the internal combustion engine is sufficiently warmed up and the refrigerant temperature is equal to or higher than a predetermined lower limit temperature and the thermoelectric conversion by the thermoelectric power generator 10 is to be intensively performed, and when the refrigerant temperature is equal to or higher than the predetermined upper limit temperature, the refrigerant temperature In the case where it is desired to avoid a further rise in the temperature, as shown in FIG. 19, it is possible to preferentially perform only the thermoelectric conversion by the thermoelectric power generator 10 by closing the exhaust flow passage to the heat recovery device 20. it can.

〔effect〕
As described above, according to the system 302e of the second embodiment as well, the heat exchange by the heat recovery unit and the thermoelectric generator according to the states of the internal combustion engine and the exhaust heat recovery unit are performed while reducing the size and complexity of the unit. The implementation and non-implementation of thermoelectric conversion can be switched independently. In this case as well, the control device 50 automatically switches between execution and non-execution of heat exchange by the heat recovery device and thermoelectric conversion by the thermoelectric power generator according to a predetermined condition as in the above-described fourth system. You may

  Next, an exhaust heat recovery system according to still another exemplary embodiment of the present invention will be described in detail below with reference to the drawings.

〔Constitution〕
FIG. 20 shows an exhaust heat recovery system according to the third embodiment of the present invention (hereinafter, referred to as a “third embodiment system 501e”) in a posture in use (for example, a posture when mounted on a vehicle). FIG. The third embodiment system 501e is an exhaust heat recovery system corresponding to the fifth system 501 and / or 502 described above.

  The third embodiment system 501e includes the above-described first embodiment unit 101e, the switching mechanism 40, the control device 50, and the bypass flow passage 60 that is an exhaust passage that does not pass through the first embodiment unit 101e. It is an exhaust heat recovery system provided.

  As shown in FIG. 20, the valve body 42 constituting the switching mechanism 40 is designed to switch the opening and closing of the exhaust gas supply flow path to the thermoelectric generator 10, the heat recovery device 20, and the bypass flow path 60 as necessary. Has a shaped. The specific shape of the valve body 42 is the shape of the thermoelectric power generation device 10, the heat recovery device 20, and the exhaust supply flow path to the bypass flow path 60, and the thermoelectric power generation device 10, the heat recovery device 20, and the It is appropriately designed according to the opening / closing pattern of the exhaust gas supply passage to the bypass passage 60.

  As shown in FIG. 20, by rotating the valve body 42 so as to close the exhaust gas supply passage to the bypass passage 60, the exhaust gas is supplied to both the thermoelectric power generation device 10 and the heat recovery device 20, and the thermoelectric power generation is performed. The thermoelectric conversion by the device 10 and the heat exchange by the heat recovery device 20 can be performed in parallel.

  Further, as shown in FIG. 21, by rotating the valve body 42 so as to close the exhaust gas supply passage to the heat recovery device 20 and the bypass passage 60, the exhaust gas is supplied only to the thermoelectric power generation device 10 and the thermoelectric generator 10 is supplied. Only the thermoelectric conversion by the power generation device 10 can be performed.

  Further, as shown in FIG. 22, by rotating the valve body 42 so as to close only the flow path of the exhaust gas to the heat recovery device 20, the exhaust gas is supplied to the thermoelectric power generator 10 and the bypass flow path 60 to generate the thermoelectric power. While performing the thermoelectric conversion by the power generation device 10, a part of the exhaust gas can be discharged through the bypass passage 60 without passing through the first embodiment unit 101e.

  In addition, when neither thermoelectric conversion by the thermoelectric power generation device 10 nor heat exchange by the heat recovery device 20 needs to be performed, the exhaust gas supply flow to the thermoelectric power generation device 10 and the heat recovery device 20 as shown in FIG. By rotating the valve body 42 so as to close both the passages, exhaust gas is supplied only to the bypass flow passage 60, and all the exhaust gas is passed through only the bypass flow passage 60 without passing through the first embodiment unit 101e. Can be discharged.

  Although some embodiments and modifications having specific configurations have been described with reference to the accompanying drawings for the purpose of describing the present invention, the scope of the present invention is not limited to these exemplary embodiments. It should be understood that the present invention should not be construed as being limited to the embodiments and the modified examples, and appropriate modifications can be made within the scope of the matters described in the claims and the specification.

  DESCRIPTION OF SYMBOLS 10 ... Thermoelectric generator, 10p ... Thermoelectric generator, 11 ... Exhaust flow path, 11f ... Fin, 12 ... Thermoelectric conversion element, 13 ... (Thermoelectric generator) case, 20 ... Heat recovery device, 20p ... Heat recovery part, 21 ... Exhaust flow path, 21f ... Fins, 23 ... Case (of heat recovery section), 30 ... Housing, 31 ... Refrigerant flow path, 31a ... Refrigerant flow path introducing section, 31b ... Refrigerant flow path deriving section, 40 ... Switching mechanism, 41 ... Rotor, 42 ... Valve body, 50 ... Control device, 51 ... Temperature detecting means, 52 ... Electric power detecting means, 60 ... Bypass passage, 101 and 102 ... Exhaust heat recovery unit, 301, 302, 401, 402, 501, 502, 601 and 602 ... Exhaust heat recovery system.

Claims (3)

Exhaust heat provided with a thermoelectric generator that generates electricity by a temperature difference between the exhaust gas discharged from the internal combustion engine and the cooling medium flowing into the internal combustion engine, and a heat recovery device that gives the heat recovered from the exhaust gas to the cooling medium. A collection unit ,
A switching mechanism that is a mechanism configured to switch the opening and closing of the exhaust flow path to the thermoelectric generator and the heat recovery unit that configure the exhaust heat recovery unit independently of each other,
A control device configured to control the switching mechanism to switch the supply of the exhaust gas to the thermoelectric generator and the heat recovery device,
An exhaust heat recovery system comprising:
A temperature detecting unit configured to detect a refrigerant temperature which is a temperature of a cooling medium flowing out from the internal combustion engine,
A power detection unit configured to detect generated power that is power generated by the thermoelectric power generator,
Further equipped with,
In the exhaust heat recovery unit ,
The thermoelectric generator and the heat recovery unit are housed in a common housing,
The thermoelectric generator and the heat recovery device are arranged in parallel with respect to the flow of the exhaust gas,
A coolant flow path, which is a flow path of the cooling medium in the housing, is configured to reach the heat recovery device after the cooling medium reaches the thermoelectric generator,
The control device is
When it is determined that the refrigerant temperature is lower than a predetermined lower limit temperature, the switching mechanism is controlled to open a supply passage of the exhaust gas to the heat recovery device, and the refrigerant temperature is equal to or higher than a predetermined upper limit temperature. When it is determined that the switching mechanism is controlled to close the exhaust supply passage to the heat recovery device and open the exhaust supply passage to the thermoelectric generator,
Based on the refrigerant temperature and the generated electric power, when it is determined that the temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generator is less than a predetermined upper limit temperature difference, the switching mechanism is controlled to the thermoelectric power generator. Of the exhaust gas supply passage, the temperature difference is determined to be equal to or more than the upper limit temperature difference, the switching mechanism is controlled to close the exhaust gas supply passage to the thermoelectric generator and Open the supply channel of the exhaust to the heat recovery device,
Is configured as
Exhaust heat recovery system .   Exhaust heat provided with a thermoelectric generator that generates electricity by a temperature difference between the exhaust gas discharged from the internal combustion engine and the cooling medium flowing into the internal combustion engine, and a heat recovery device that gives the heat recovered from the exhaust gas to the cooling medium. A collection unit,
  A switching mechanism that is a mechanism configured to switch the opening and closing of the exhaust flow path to the thermoelectric generator and the heat recovery unit that configure the exhaust heat recovery unit independently of each other,
  A control device configured to control the switching mechanism to switch the supply of the exhaust gas to the thermoelectric generator and the heat recovery device,
An exhaust heat recovery system comprising:
  A bypass flow passage that is a flow passage for exhaust gas that does not pass through the exhaust heat recovery unit;
  A temperature detecting unit configured to detect a refrigerant temperature which is a temperature of a cooling medium flowing out from the internal combustion engine,
  A power detection unit configured to detect generated power that is power generated by the thermoelectric power generator,
Further equipped with,
  The switching mechanism is configured to independently switch between opening and closing of the thermoelectric generator and the heat recovery unit that configure the exhaust heat recovery unit and the exhaust supply flow path to the bypass flow path,
  The control device is configured to control the switching mechanism to switch the supply of the exhaust gas to the thermoelectric generator, the heat recovery device, and the bypass flow path,
  In the exhaust heat recovery unit,
    The thermoelectric generator and the heat recovery unit are housed in a common housing,
    The thermoelectric generator and the heat recovery device are arranged in parallel with respect to the flow of the exhaust gas,
    A coolant flow path, which is a flow path of the cooling medium in the housing, is configured to reach the heat recovery device after the cooling medium reaches the thermoelectric generator,
  The control device is
    When it is determined that the refrigerant temperature is lower than a predetermined lower limit temperature, the switching mechanism is controlled to open a supply passage of the exhaust gas to the heat recovery device, and the refrigerant temperature is equal to or higher than a predetermined upper limit temperature. If it is determined that the switching mechanism is controlled to close the exhaust flow path to the heat recovery device,
    Based on the refrigerant temperature and the generated power, when it is determined that the temperature difference between the exhaust gas and the cooling medium in the thermoelectric power generator is less than a predetermined upper limit temperature difference, the switching mechanism is controlled to the thermoelectric power generator. Of the exhaust gas supply passage of the, the temperature difference is determined to be equal to or more than the upper limit temperature difference, the switching mechanism is controlled to close the exhaust gas supply passage to the thermoelectric generator,
    When both the exhaust supply flow path to the heat recovery device and the exhaust supply flow path to the thermoelectric generator are simultaneously closed, the switching mechanism is controlled to supply the exhaust flow to the bypass flow path. Open the flow path,
Is configured as
Exhaust heat recovery system. The exhaust heat recovery system according to claim 1 or 2 , wherein
In the housing in the posture when the exhaust heat recovery unit is in use,
The cooling medium is introduced into the housing from the lower side in the vertical direction, so as to be led out from the upper side in the vertical direction, the refrigerant flow path is configured,
The thermoelectric generator is on the lower side in the vertical direction, the heat recovery device is arranged on the upper side in the vertical direction,
Exhaust heat recovery system .

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