JP5381337B2 - Waste heat recovery device - Google Patents

Description

  The present invention relates to an exhaust heat recovery apparatus that can promote the temperature rise of an appropriate heating target in a vehicle such as an automobile using exhaust heat of an internal combustion engine.

  Conventionally, the heat of exhaust gas from an internal combustion engine mounted on a vehicle such as an automobile is recovered with a heat pipe to promote warm-up (activation) of the catalyst, or to promote warm-up of the internal combustion engine. It is known to use for such as (see Patent Documents 1 to 3).

  The conventional example according to Patent Document 1 is an evaporation unit (equivalent to a heat receiving unit) that recovers exhaust heat from an exhaust passage of an internal combustion engine and evaporates a fluid, and a condensing unit (equivalent to a heat dissipation unit) that condenses the evaporated fluid. ) Are integrated in a state where they are arranged next to each other and connected to a closed loop, and this cooling water is provided by arranging a part of the cooling water flow path of the internal combustion engine close to the condensing part. Heat exchange between the gas and the gaseous fluid. In this conventional example, the volume of the internal space of the condensing part is set constant.

  In the conventional example according to Patent Document 2, the lower half of the plurality of heat pipes 110 is arranged in the exhaust passage of the internal combustion engine to be an evaporation unit (corresponding to a heat receiving unit) 110A, and the upper half of the plurality of heat pipes 110 is the internal combustion engine. There is disclosed a configuration in which a condensing part (corresponding to a heat radiating part) 110B is arranged in the cooling water passage, and a valve body 112 that is moved up and down by a thermostat 113 is provided on the condensing part 110B side of the heat pipe 110.

  As an operation of this conventional example, as shown in paragraphs 0040 to 0043, after the engine is started, the outer periphery of the valve body 112 is separated from the valve seat 111b until the cooling water temperature reaches a predetermined temperature. The condensed water in the condensing unit 110B returns to the evaporating unit 110A along the inner wall surface 111a of the heat pipe 110. On the other hand, when the cooling water temperature is equal to or higher than the predetermined temperature, the valve body 112 is lowered by the thermostat 113 and is seated on the valve seat 111b, and the condensed water in the condensing unit 110B is not recirculated to the evaporating unit 110A, Water heating is stopped.

  In the conventional example according to Patent Document 3, the lower half of the plurality of heat pipes 110 is arranged in the exhaust passage of the internal combustion engine to be an evaporation unit (corresponding to a heat receiving unit) 110A, and the upper half of the plurality of heat pipes 110 is the internal combustion engine. Placed in the cooling water passage as a condensing part (corresponding to a heat radiating part) 110B, the lower end of the evaporating part 110A of each heat pipe 110 communicates with the communication tank 140, and the medium capacity can be changed at one end of the communication tank 140 A configuration in which a medium container 130 is provided is disclosed.

  As the operation of this conventional example, as shown in paragraph 0039, when the exhaust gas temperature is high, the pressure in the heat pipe 110 rises, and the bellows 131 is extended to increase the medium capacity of the medium container 130. As a result, the amount of water in the heat pipe 110 decreases, and the heat transport capability decreases. On the other hand, when the exhaust gas temperature is low, the pressure in the heat pipe 110 decreases, the bellows 131 contracts, and the medium capacity of the medium container 130 decreases, so the amount of water in the heat pipe 110 increases and heat transport Ability increases.

JP 2008-14304 A JP 2006-317013 A JP 2006-292337 A

  When the volume of the internal space of the condensing part (corresponding to the heat radiating part) is made constant as in the conventional example according to Patent Document 1, there is room for improvement in the following points.

  First, if the volume of the internal space of the condensing unit is set large in order to increase the heat exchange capability with the heating target by the condensing unit, for example, when the internal combustion engine is cold started, the fluid in the evaporation unit (corresponding to the heat receiving unit) Since the amount of evaporation is small, a sufficient amount of steam cannot be sent from the evaporation section to the condensation section, and it takes time to start up the heat exchange capacity of the condensation section. Therefore, if the cross-sectional area of the fluid transfer path from the evaporation section to the condensation section is increased to increase the amount of steam transferred, the steam rubs against the inner wall surface of the fluid transfer path and the heat of the steam is lost. On the contrary, the heat transport capability from the evaporation section to the condensation section is likely to be reduced, and it takes time to raise the temperature of the heating target.

  On the other hand, if the volume of the condensing unit is set to be small, for example, when the internal combustion engine is cold started, the amount of fluid evaporation in the evaporation unit (corresponding to the heat receiving unit) is small, but it is evaporated without being condensed in the condensing unit. Since the amount passing through the part increases, it becomes easy for steam to accumulate in the heat circulation path between the evaporation part and the condensation part, and it is possible to start up quickly to a state where heat recovery by the evaporation part can be performed efficiently. . However, of course, due to the small volume of the condensing part, the heat exchanging capacity of the condensing part is insufficient, and it takes time to raise the temperature of the heating target. Thus, it was difficult to set the volume of the condensing part.

  In the conventional example according to Patent Document 2, by switching to a state in which the reflux of condensed water from the condensing unit (corresponding to the heat radiating unit) 110B to the evaporating unit (corresponding to the heat receiving unit) 110A is allowed or prevented, However, the technical idea of adjusting the heat exchange capacity of the condensing unit 110B cannot be heard.

  In the conventional example according to Patent Document 3, the heat transport capacity from the evaporation unit 110A to the condensation unit 110B is changed by changing the amount of medium contained in the evaporation unit (corresponding to the heat receiving unit) 110A according to the temperature of the exhaust gas. To change. However, in this conventional example, there is no disclosure or suggestion of a technical idea that, as in the present invention, the state of heat recovery can be efficiently started and then the state is shifted to a state in which the heat exchanging ability by the heat radiating portion is increased. . Therefore, as a matter of course, in this conventional example, there is no description about a configuration in which the volume of the internal space of the condensing unit can be changed in order to realize the technical idea.

  In view of such circumstances, the present invention provides a heat receiving portion that is provided in an exhaust passage of an internal combustion engine and evaporates an internal fluid with exhaust heat, and receives the fluid evaporated in the heat receiving portion and heats the fluid. In a heat recovery system with a loop heat pipe structure that includes a heat radiating part for heat exchange with the target, heat exchange capacity by the heat radiating part is started after it is quickly set up so that heat can be efficiently recovered by the heat receiving part. The purpose is to make it possible to quickly raise the temperature of the heating target by shifting to a state in which the temperature is increased.

The present invention provides a heat receiving portion that is provided in an exhaust passage of an internal combustion engine and evaporates an internal fluid with exhaust heat, receives a fluid evaporated in the heat receiving portion, and exchanges heat between the fluid and a heating target. A loop heat pipe structure including a heat radiating part for transferring the fluid, a transfer path for transferring a fluid from the heat receiving part to the heat radiating part, and a return path for returning the fluid from the heat radiating part to the heat receiving part. a heat recovery device, the heat radiating portion is adjustment mechanism for adjusting the effective heat exchange area between the heat target with the fluid is provided by controlling the flow of fluid introduced, the heat dissipation The part has a case that is provided in a state in which heat can be exchanged with the object to be heated and to which the transfer path and the reflux path are connected, and the adjustment mechanism is housed in the case so as to be displaceable and the arrangement position thereof According to the case A flow control member for controlling the flow of the fluid introduced into the fluid, and a drive unit for displacing the flow control member, wherein the drive unit is set so that the temperature of the heating target is lower than the final target temperature. When the temperature is lower than the first target temperature, the flow control member is disposed at a first position that brings the fluid introduction position from the transfer path into the case closer to the connection portion side of the transfer path with respect to the case. When the temperature is equal to or higher than the first target temperature and lower than the final target temperature, the flow control member is disposed at a second position that moves the fluid introduction position from the transfer path into the case away from the connection portion side of the transfer path to the case is, when the temperature of the heating target is not less than the final target temperature, thereby placing the flow control member to a third position to stop fluid discharge from the fluid introduction or case into the case, it It is characterized.

  In this configuration, for example, if the effective heat exchange area is reduced by the adjustment mechanism at the start of heat recovery by the heat receiving unit, the amount of the gas-phase fluid in the heat radiating unit passing through the heat receiving unit without being condensed increases. As a result, the vapor-phase fluid evaporated in the heat receiving part can be quickly filled in the heat circulation path between the heat receiving part and the heat radiating part, so that the heat recovery by the heat receiving part can be efficiently performed at an early stage. It becomes possible to start up.

  In this way, if the effective heat exchange area is increased by the adjusting mechanism after the gas-phase fluid is filled in the heat circulation path, the temperature rise of the heating target is promoted. In addition, at this stage, since a large amount of gas-phase fluid exists in the heat circulation path, the movement of the gas-phase fluid from the heat receiving section to the heat radiating section becomes slow, and the fluid transfer path The heat loss due to the friction of the fluid against the inner wall surface is suppressed. This also enables efficient heat transport.

  In this way, it is possible to shift to a state where the heat exchange capacity of the heat radiating unit can be increased after it has been set up early in a state where heat recovery by the heat receiving unit can be efficiently performed, thereby quickly raising the temperature of the heating target. It becomes possible to make it.

Moreover, in the said structure, the gaseous-phase fluid evaporated in the heat receiving part will be introduce | transduced in the case of a thermal radiation part through a transfer path. At that time, the flow of the fluid introduced into the case is controlled by appropriately changing the arrangement position of the flow control member accommodated in the case by the driving unit. The effective heat exchange area between the fluid and the heating target is adjusted according to the flow of the fluid.

  Then, depending on the position of the flow control member in the case, it is possible to move the fluid introduction position from the transfer path into the case closer to or away from the connection part side of the return path with respect to the case. The flow of fluid inside changes.

  For example, when the fluid introduction position from the transfer path into the case is brought closer to the connection part side of the return path with respect to the case, the fluid flows only in a relatively short area in the case. The area where heat exchange is possible becomes small. Also, if the fluid introduction position from the transfer path into the case is moved away from the connection part side of the return path to the case, the fluid flows in a relatively long region in the case. Increases the area where heat exchange is possible.

Furthermore, in the said structure, it arrange | positions a flow control member in the 1st-3rd position according to a condition, changes the way of the flow of a fluid, thereby changing an effective heat exchange area, or the fluid to a thermal radiation part. The heat circulation of the exhaust heat recovery device is stopped by stopping the fluid discharge from the introduction or the heat radiation part.

  For example, when the flow control member is arranged at the first position, the fluid introduction position from the transfer path into the case approaches the connection part side of the return path to the case, so that the fluid is only in a relatively short region in the case. The area where the fluid and the object to be heated can exchange heat is reduced in the case.

  Further, when the flow control member is arranged at the second position, the fluid introduction position from the transfer path into the case moves away from the connection part side of the return path to the case, so that the fluid flows in a relatively long region in the case. Thus, the area in which heat exchange between the fluid and the object to be heated can be increased in the case.

  Furthermore, if the flow control member is displaced to the third position, the fluid cannot flow from the transfer path connection to the case to the return path connection to the case, so that the heat circulation of the exhaust heat recovery device is stopped. Therefore, heating of the heating target can be stopped, so that the heating target does not have to be heated more than necessary.

  Preferably, the case is formed in a cylindrical shape, an inner diameter dimension of a substantially half region in the axial direction is set to be larger than that of the remaining substantially half region in the center hole, and the transfer path is formed in the opening of the large diameter portion. The reflux path is connected to the opening of the small-diameter portion, the heating object is arranged on the outer periphery of the case in a heat-exchangeable state, and the flow control member is a bottomed cylindrical member In addition, through holes are provided at several locations around the outer periphery at the bottom, and the inner diameter of the inscribed circle of each through hole is set larger than the inner diameter of the small diameter portion at the bottom. The large-diameter portion is accommodated in a linearly displaceable manner along the axial direction of the large-diameter portion in a state where the opening is directed to the connection portion of the transfer path with respect to the large-diameter portion.

  Here, by specifying the configuration of the case and the flow control member, the configuration for changing the flow of the fluid in the heat radiating portion according to the arrangement position of the flow control member in the case is clarified.

  When the flow control member is displaced to the first position where the opening coincides with the opening of the large-diameter portion of the case, all the fluid introduced from the transfer path enters the cylindrical portion of the flow control member. As a result, it is discharged only from the through hole at the bottom of the flow control member, and flows into the small diameter portion relatively quickly. In this case, the fluid introduction position from the transfer path into the case approaches the connection part side of the return path with respect to the case. As a result, the fluid exchanges heat with the heating target on the outer periphery of the case through the small diameter portion in the center hole of the case, so that the area where the fluid and the heating target can exchange heat is reduced. In other words, the effective heat exchange area by the heat radiating portion is reduced.

  Further, when the flow control member is displaced to the second position in the axial direction in the large diameter portion of the case, the fluid introduced from the transfer path enters the cylindrical portion of the flow control member and enters the through hole in the bottom portion. In addition to being discharged, the fluid overflows from the opening of the cylindrical portion and flows toward the small diameter portion through the space between the cylindrical portion and the large diameter portion of the case. In this case, the fluid introduction position from the transfer path into the case is moved away from the connection part side of the return path to the case. As a result, the fluid exchanges heat with the object to be heated through substantially the entire center hole of the case, so that the area in which the fluid and the object to be heated can exchange heat is increased. In other words, the effective heat exchange area by the heat radiating portion is increased.

  Further, when the flow control member is displaced to a third position where the bottom part contacts the stepped wall surfaces of the large diameter part and the small diameter part of the case, the inner diameter side of the inscribed circle of each through hole at the bottom part of the flow control member The communication portion between the large diameter portion and the small diameter portion is blocked in the region. In this case, since the fluid introduced to the large diameter portion side does not flow to the small diameter portion, the heat circulation of the exhaust heat recovery device is stopped. Therefore, heating of the heating target can be stopped, so that the heating target does not have to be heated more than necessary.

  Preferably, the heating target is cooling water that is once taken out from the internal combustion engine and then returned, the middle of the external flow path of the cooling water is divided, and an upstream end and a downstream end in the cooling water flow direction Is connected to an internal flow path provided in the outer peripheral wall of the case.

  In this configuration, the heating target is specified as the cooling water taken out of the internal combustion engine, and the installation state of the heating target with respect to the case is specified. Here, a part of the external flow path for circulating the cooling water as the heating target is provided as an internal flow path in the outer peripheral wall of the case. When specified in this way, heat exchange between the cooling water in the internal flow path of the case and the fluid introduced into the center hole of the case can be performed relatively efficiently.

  Preferably, the internal flow path includes a hollow portion provided in the outer peripheral wall of the case and a partition wall provided at one place in a circumferential direction of the hollow portion, and one of the partition walls is provided in the hollow portion. The upstream end of the external flow path is connected to the side, and the downstream end of the external flow path is connected to the other side of the partition wall in the hollow portion.

  In this configuration, the configuration of the internal flow path of the case is specified, and in this case, the internal flow of the case is compared with the case where a part of the external flow path of the cooling water is incorporated in the outer peripheral wall of the case. The work when connecting the external flow path to the flow path is simplified.

  Preferably, when the temperature of the heating target is lower than a first target temperature set lower than a final target temperature, the driving unit has an opening that matches the opening of the large-diameter portion of the case. When the temperature of the object to be heated is equal to or higher than the first target temperature and lower than the final target temperature, the flow control member is disposed at a second position in the axial direction of the large diameter portion of the case. When the temperature of the heating target is equal to or higher than the final target temperature, the flow control member is arranged at a third position where the bottom part abuts on the step wall surface of the large diameter part and the small diameter part of the case. Can do.

  In this configuration, the flow control member is arranged at the first to third positions according to the situation, so that the way of fluid flow is changed, thereby changing the effective heat exchange area, or the fluid flow at the heat radiating unit. The heat circulation of the exhaust heat recovery device is stopped and stopped.

  Preferably, the case is attached to the heating target such that a partial region on the outer periphery of the heating target enters the internal space, and the partial region of the heating target is approximately divided into two in the internal space of the case. A partition wall is provided for partitioning into two rooms at a position where the partition wall is provided with a communication hole for communicating the two rooms, the transfer path in the first chamber, and the first chamber. A reflux path is connected to each of the two chambers, and the flow control member is a cylindrical member having a bottom, and through holes are provided at several locations near the outer periphery at the bottom, and each through-hole is formed at the bottom. The inner diameter dimension of the inscribed circle of the hole is set to be larger than the inner diameter dimension of the small diameter portion, and the flow control member is arranged so that the opening portion faces the connection portion of the transfer path with respect to the first chamber. Between partition walls Is linear displaceable housed.

  Here, by specifying the configuration of the case and the flow control member, the configuration for changing the flow of the fluid in the heat radiating portion according to the arrangement position of the flow control member in the case is clarified.

  When the flow control member is displaced to the first position where the opening coincides with the connection portion of the transfer path with respect to the first chamber, all fluid introduced from the transfer path enters the cylindrical portion of the flow control member. As a result, the fluid is discharged only from the through hole at the bottom of the flow control member, and flows into the second chamber through the communication hole of the partition wall relatively quickly. In this case, the fluid introduction position from the transfer path into the case approaches the communication hole side of the partition wall in the first chamber. As a result, heat exchange between the fluid and the object to be heated is performed in the second chamber, so that an area in which heat exchange between the fluid and the object to be heated can be reduced in the case. In other words, the effective heat exchange area by the heat radiating portion is reduced.

  Further, when the flow control member is displaced to the second position in the displacement direction in the first chamber, the fluid introduced from the transfer path enters the cylindrical portion of the flow control member and is discharged from the through hole in the bottom portion. As a result, the fluid flows relatively quickly into the second chamber through the communication hole of the partition wall, and the fluid overflows from the opening of the cylindrical portion and is discharged to the connecting portion side with the transfer path in the first chamber. Thus, it flows toward the communication hole side of the partition wall. In this case, the fluid introduction position from the transfer path into the case is moved away from the connection part side of the return path to the case. As a result, the fluid is exchanged with the object to be heated through both the first and second chambers of the case, so that the area in the case where the fluid and the object to be heated can exchange heat is increased. In other words, the effective heat exchange area by the heat radiating portion is increased.

  Further, when the flow control member is displaced to a third position where the bottom of the flow control member comes into contact with the outer peripheral edge of the partition wall, the communication hole of the partition wall is formed in the inner diameter side region of the inscribed circle of each through hole at the bottom of the flow control member. Will be blocked. In this case, since the fluid introduced into the first chamber does not flow to the second chamber, the heat circulation of the exhaust heat recovery device is stopped. Therefore, heating of the heating target can be stopped, so that the heating target does not have to be heated more than necessary.

  Preferably, the object to be heated is a catalyst installed in an exhaust system of an internal combustion engine, and the outer shape of the catalyst is cylindrical, and a substantially semicircular region on the outer periphery of the catalyst enters the internal space of the case. In this case, approximately 1/4 of the outer circumference of the catalyst is present in each of the two rooms.

  In this configuration, the heating target is specified as the exhaust system catalyst of the internal combustion engine, and the installation state of the heating target with respect to the case is specified. Here, it is specified that a part of the catalyst to be heated is exposed in the case. When specified in this way, heat exchange between the catalyst and the fluid introduced into the case can be performed relatively efficiently.

  Preferably, when the temperature of the heating target is lower than a first target temperature set lower than a final target temperature, the drive unit causes the flow control member to be connected to a transfer path connecting portion to the first chamber. When the temperature of the heating target is equal to or higher than the first target temperature and lower than the final target temperature, the flow control member is positioned at a second position in the middle of the displacement direction in the first room. When the temperature of the heating target is equal to or higher than the final target temperature, the flow control member can be arranged at a third position where the bottom of the flow control member comes into contact with the outer peripheral edge of the partition wall.

  In this configuration, the flow control member is arranged at the first to third positions according to the situation, so that the way of fluid flow is changed, thereby changing the effective heat exchange area, or the fluid flow at the heat radiating unit. The heat circulation of the exhaust heat recovery device is stopped and stopped.

  Preferably, the drive unit is configured to automatically displace the flow control member in accordance with preset operating conditions.

  The operating condition is, for example, a magnitude relationship of the internal pressure of the transfer path with respect to an appropriate determination reference value, or a magnitude relationship of the temperature of the heating target with respect to an appropriate determination reference value. It comes to sense.

  When specified in this way, it is advantageous in simplifying the configuration and reducing the cost as compared with the case of using a device for electrically controlling the displacement operation of the flow control member.

  Preferably, the drive unit is configured to displace the flow control member using an actuator or a control device in accordance with preset operating conditions.

  The operating condition is, for example, a magnitude relation of the internal pressure of the transfer path with respect to an appropriate judgment reference value, or a magnitude relation of the temperature of the heating target with respect to an appropriate judgment reference value, and the control device judges these relations. It is supposed to be.

  When specified in this way, it is possible to set the determination criterion for the displacement operation of the flow control member relatively easily, which is advantageous in enhancing versatility.

  According to the exhaust heat recovery apparatus of the present invention, the target to be heated is quickly increased by quickly starting up to a state where heat recovery by the heat receiving unit can be performed efficiently and then shifting to a state where the heat exchange capability by the heat dissipation unit is increased. It becomes possible to warm.

It is a schematic block diagram which shows one Embodiment of the waste heat recovery apparatus which concerns on this invention. It is the perspective view which decomposed | disassembled the thermal radiation part of FIG. It is the figure which looked at the case main body of the thermal radiation part of FIG. It is sectional drawing which shows the specific structure of the waste heat recovery apparatus of FIG. 1, and has shown the state which has arrange | positioned the flow control member in the 1st position. It is sectional drawing which shows the state which has arrange | positioned the flow control member in the 2nd position in FIG. It is sectional drawing which shows the state which has arrange | positioned the flow control member in the 3rd position in FIG. It is a schematic block diagram which shows other embodiment of the waste heat recovery apparatus which concerns on this invention. It is sectional drawing which shows the specific structure of the waste heat recovery apparatus of FIG. 7, and has shown the state which has arrange | positioned the flow control member in the 1st position. It is sectional drawing which shows the state which has arrange | positioned the flow control member in the 2nd position in FIG. It is sectional drawing which shows the state which has arrange | positioned the flow control member in the 3rd position in FIG.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  1 to 6 show an embodiment of the present invention. In this embodiment, an exhaust heat recovery device applied to an internal combustion engine mounted on a vehicle is taken as an example. With reference to FIG. 1, a schematic configuration of the exhaust heat recovery apparatus will be described. In the figure, 1 is a water-cooled internal combustion engine.

  The internal combustion engine 1 supplies an air-fuel mixture obtained by mixing air supplied from an intake system and fuel supplied from a fuel supply system at an appropriate air-fuel ratio to the combustion chamber of the internal combustion engine 1 for combustion. The exhaust gas in the combustion chamber is released from the exhaust system to the atmosphere.

  The exhaust system has at least an exhaust manifold 2 attached to the internal combustion engine 1 and an exhaust pipe 4 connected to the exhaust manifold 2 via a spherical joint 3. The exhaust manifold 2 and the exhaust pipe 4 constitute an exhaust passage.

  The spherical joint 3 allows an appropriate swing between the exhaust manifold 2 and the exhaust pipe 4 and functions so as not to transmit the vibration and movement of the internal combustion engine 1 to the exhaust pipe 4 or to attenuate and transmit them.

  Two catalysts 5 and 6 are installed in the exhaust pipe 4 in series, and the exhaust gas is purified by the two catalysts 5 and 6.

  Among these catalysts 5, 6, the catalyst 5 installed upstream in the exhaust gas flow direction in the exhaust pipe 4 is called a so-called start catalyst (S / C), and is called an upstream catalyst. On the other hand, the catalyst 6 installed on the downstream side in the exhaust gas flow direction in the exhaust pipe 4 is a so-called main catalyst (M / C) or underfloor catalyst (U / F). I will say.

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

  In the internal combustion engine 1, a refrigerant called a long life coolant (LLC) (hereinafter simply referred to as “cooling water”) enclosed in the internal combustion engine 1 is once taken out from the cooling water take-out passage 8 and supplied to the radiator 7. To the internal combustion engine 1 through the cooling water recirculation passage 9. The radiator 7 cools the cooling water circulated by the water pump 10 by heat exchange with the outside air.

  The amount of cooling water flowing through the radiator 7 and the amount of cooling water flowing through the bypass passage 12 are adjusted by the thermostat 11. For example, at the time of warming up, the amount of cooling water on the bypass path 12 side is increased to promote warming up, and overcooling of the cooling water by the radiator 7 is prevented.

  A heater core 14 is provided in the middle of the heater flow path 13 branched from the cooling water take-out path 8 and connected to the upstream side of the water pump 10 in the cooling water recirculation path 9. The heater core 14 is a heat source for heating the passenger compartment using the heat of the cooling water. The air heated by the heater core 14 is introduced into the vehicle interior by the blower fan 15. The heater core 16 and the blower fan 15 constitute a heater unit 16. In the heater flow path 13, the temperature of the cooling water flowing in the downstream area from the heater core 14 becomes low due to heat radiation from the heater core 14.

  An exhaust heat recovery device 20 is attached to the exhaust system of the internal combustion engine 1 having such a configuration.

  The exhaust heat recovery device 20 is configured to recover the heat of the exhaust gas discharged from the internal combustion engine 1 to promote the temperature rise of the cooling water of the internal combustion engine 1, for example. 22, a loop heat pipe structure including a transfer path 23 and a reflux path 24.

  Note that the exhaust heat recovery device 20 having a loop heat pipe structure is such that the fluid is circulated between the heat receiving portion 21 and the heat radiating portion 22 while being circulated to repeat exhaust heat recovery and heat dissipation. That is.

  The exhaust heat recovery apparatus 20 in the illustrated example is a separate type in which the heat receiving part 21 and the heat radiating part 22 are arranged separately.

  The inside of the exhaust heat recovery device 20 is in a vacuum state, and an appropriate amount of fluid is sealed therein. The fluid is pure water, for example. The boiling point of water is 100 ° C. at 1 atmosphere, but since the pressure inside the exhaust heat recovery apparatus 1 is reduced (for example, 0.01 atmosphere), the boiling point is, for example, 5 to 10 ° C. In addition to pure water, the fluid can be, for example, alcohol, fluorocarbon, or chlorofluorocarbon. Moreover, the main component of the exhaust heat recovery apparatus 20 is formed, for example with the stainless steel material provided with high corrosion resistance.

  The heat receiving part 21 is installed downstream of the downstream catalyst 6 in the exhaust pipe 4 so that the liquid phase fluid sealed inside receives the exhaust heat and evaporates to recover heat as vaporization heat. It is configured.

  Specifically, the heat receiving portion 21 is installed in a direction orthogonal to the exhaust gas passage direction with respect to the exhaust pipe 4. For example, as shown in FIG. 4, the upper tank 21 a and the lower tank 21 b are connected to each other. A plurality of fins 21e... Are provided in the exhaust passage 21d between the opposing fluid passages 21c in communication with each other through a plurality of fluid passages 21c. The fin 21e is a corrugated type so as to increase the heat exchange area. The corrugated fin 21e is formed, for example, by forming a thin strip plate into a waveform in the circumferential direction by roller processing.

  The upper tank 21a is a high-temperature side tank because mainly evaporated vapor phase fluid is collected. The lower tank 21b is a low-temperature side tank because mainly condensed liquid phase fluid is collected.

  The heat radiating part 22 is attached to the heater flow path 13 to be heated, receives the fluid made into steam by the heat receiving part 21, and transmits the heat of this fluid to the cooling water in the heater flow path 13. Yes, the fluid is condensed with heat transfer and returned to the heat receiving unit 21. The configuration of the heat radiating portion 22 will be described in detail later.

  The transfer path 23 is a pipe for connecting the upper tank 21 a of the heat receiving part 21 and the internal space of the heat radiating part 22, and transfers the gas-phase fluid evaporated in the heat receiving part 21 to the heat radiating part 22. .

  The reflux path 24 is a pipe for connecting the internal space of the heat radiating unit 22 and the lower tank 21 b of the heat receiving unit 21, and returns the liquid-phase fluid condensed in the heat radiating unit 22 to the heat receiving unit 21. The reflux path 24 has an appropriate downward gradient so that the liquid-phase fluid condensed in the heat radiating section 22 can be easily returned to the heat receiving section 21.

  Next, a basic operation at the time of cold start of the internal combustion engine 1 will be described. In short, when the internal combustion engine 1 is cold-started, all of the upstream side catalyst 5, the downstream side catalyst 6, and the cooling water of the internal combustion engine 1 are at a low temperature. Therefore, when the internal combustion engine 1 is started, exhaust gas of 300 to 400 ° C., for example, is discharged from the internal combustion engine 1 through the exhaust manifold 2 to the exhaust pipe 4 so that the two catalysts 5 and 6 are exhausted from the inside. While the temperature is increased, the cooling water is returned to the internal combustion engine 1 through the bypass passage 12 without passing through the radiator 7, so that the warm-up operation is performed.

  During the warm-up operation, the exhaust heat recovery device 20 further heats the cooling water of the internal combustion engine 1 to promote the warm-up operation.

  A basic operation of the exhaust heat recovery apparatus 20 will be described. When the exhaust gas discharged from the internal combustion engine 1 through the exhaust manifold 2 to the exhaust pipe 4 reaches the heat receiving part 21, the liquid phase fluid in the heat receiving part 21 is heated by the heat of the exhaust gas and evaporated. It will be.

  This vaporized fluid in the vapor phase is transferred to the heat radiating unit 22 through the transfer path 23. The heat of the gas-phase fluid sent to the heat radiating part 22 is transmitted to the cooling water in the heater flow path 13. As a result, the heated cooling water is returned to the internal combustion engine 1 and warming up of the internal combustion engine 1 is promoted.

  Along with the heat exchange between the high-temperature gas-phase fluid introduced into the heat radiating section 22 and the cooling water in the heater flow path 13, the gas-phase fluid in the heat radiating section 22 is condensed to form a liquid phase. It becomes a shape. The liquid phase fluid is returned from the reflux path 24 to the heat receiving unit 21. Thereafter, the coolant in the heater channel 13 is heated by circulating the fluid between the heat receiving unit 21 and the heat radiating unit 22 while performing phase transition.

  Next, the configuration of the heat radiating unit 22 will be described in detail with reference to FIGS. The heat radiating portion 22 has a case 25. The case 25 has a two-piece structure including a cylindrical case body 26 and a joint cover 27.

  The center hole of the case body 26 is set so that the inner diameter dimension of the half region 26a in the axial direction is larger than that of the remaining half region 26b. Hereinafter, the large-diameter half region 26a is referred to as a large-diameter portion, and the small-diameter half region 26b is referred to as a small-diameter portion. A wall surface along the radial direction of the step portion between the large diameter portion 26a and the small diameter portion 26b, that is, a step wall surface is denoted by reference numeral 26c.

  Further, a hollow portion 26d is formed in a region from the one axial end side to the front of the axial other end in the outer peripheral wall of the case body 26. A partition wall 26e is provided at one place in the circumferential direction of the hollow portion 26d.

  The joint cover 27 is attached to the opening end of the large diameter portion 26a in the center hole of the case body 26 so as to close the opening end and the opening of the hollow portion 26d. The joint cover 27 is a circular plate, and a small-diameter cylindrical portion 27a that protrudes toward one side in the axial direction is provided at the center thereof. A transfer path 23 is connected to the small diameter cylindrical portion 27 a of the joint cover 27, whereby the transfer path 23 is connected to the large diameter portion 26 a of the center hole of the case body 26. A reflux path 24 is connected to the small diameter portion 26 b of the center hole of the case body 26.

  Furthermore, an upstream side end portion 13a in the cooling water flow direction that is divided in the middle of the heater flow path 13 as an external flow is connected to one side of the partition wall 26e in the hollow portion 26d of the case body 26, and in the hollow portion 26d Connected to the other side of the partition wall 26e is a downstream end 13b in the coolant flow direction that is divided in the middle of the heater flow path 13. Thus, the cooling water taken out from the internal combustion engine 1 to the heater flow path 13 is introduced into the hollow portion 26d of the case body 26 as shown by the arrow in FIG. And then returned to the heater flow path 13. Thus, the hollow part 26d and the partition wall 26e of the case main body 26 constitute a part of the external flow path. In the case of the heat dissipating part 22 having such a configuration, the heat of the high-temperature gas-phase fluid sent from the transfer path 23 into the center hole of the case body 26 passes through the inner peripheral surface of the center hole of the case body 26. Then, it is transmitted to the cooling water in the hollow portion 26d of the case body 26.

  Such a heat radiating unit 22 is provided with an adjustment mechanism for adjusting the effective heat exchange area between the fluid and the cooling water of the internal combustion engine 1, that is, the heating capacity. This adjustment mechanism mainly includes a flow control member 31 and a drive unit 32.

  In short, the flow control member 31 is accommodated in the case main body 26 so as to be displaceable, and controls the flow of the fluid introduced into the case main body 26 according to the arrangement position. Specifically, the flow control member 31 has a bottomed cylindrical member, that is, a cup shape, as shown in FIG. The opening of the flow control member 31 is provided with flanges 31a that project outward in the radial direction, and through holes 31b are provided at several locations near the outer periphery of the bottom of the flow control member 31. Yes. Furthermore, one end of a rod-shaped power transmission member 33 is connected to the center of the bottom of the flow control member 31.

  The flow control member 31 has the opening directed toward the opening of the large diameter portion 26a of the case main body 26 and extends along the axial direction of the large diameter portion 26a in the large diameter portion 26a of the central hole of the case main body 26. It is housed in a linearly displaceable manner.

  The inner diameter dimension of the inscribed circle inscribed in each through hole 31 b at the bottom of the flow control member 31 is set larger than the inner diameter dimension of the small diameter portion 26 b of the case body 26. Thus, the inner diameter side region of the inscribed circle at the bottom of the flow control member 31 closes the small diameter portion 26b of the case main body 26 in a state where the inner peripheral side region of the center hole of the case main body 26 is in contact with the outer peripheral edge of the step wall surface 26c. Is possible.

  The drive unit 32 is of a self-actuating type that automatically displaces the flow control member 31 in three stages according to preset operating conditions. Although not shown, the self-actuating type drive unit 32 has a known configuration using a diaphragm spring. The other end of the rod-shaped power transmission member 33 connected to the flow control member 31 is connected to the diaphragm spring.

  As the operation of the drive unit 32, the diaphragm spring is elastically deformed from the natural posture by the internal pressure of the transfer path 23, and the power transmission member 33 is linearly pushed and pulled according to the posture change of the diaphragm spring. The flow control member 31 is displaced.

  For example, when the steam is not present in the transfer path 23 such as when the internal combustion engine 1 is cold started, the flow control member 31 is connected to the first position shown in FIG. 4, that is, the flange 31 a of the flow control member 31. It arrange | positions in the position contact | abutted to the inner surface of the cover 27. FIG. Thereby, although the temperature of the cooling water of the internal combustion engine 1 gradually rises, when the internal pressure of the transfer path 23 is equal to or higher than the first determination reference value and lower than the second determination reference value, the flow control member 31 is shown in FIG. When the cooling water temperature of the internal combustion engine 1 is equal to or higher than the warm-up temperature and the internal pressure of the transfer path 23 is equal to or higher than the second determination reference value, the flow control member 31 is The third position shown in FIG.

  Next, the operation of the adjustment mechanism having the above-described configuration will be described.

  First, when the internal combustion engine 1 is cold-started, it is assumed that the temperatures of the two catalysts 5 and 6 are low and no steam exists in the closed loop of the exhaust heat recovery device 20. At this time, the drive part 32 shall arrange | position the collar part 33 of the flow control member 31 of an adjustment mechanism in the position (1st position shown in FIG. 4) contact | abutted to the inner surface of the joint cover 27. FIG.

  Here, the heat receiving unit 21 recovers the heat of the exhaust gas that has passed through the downstream catalyst 6, whereby the liquid-phase fluid present in the heat receiving unit 21 is evaporated. The resulting gas-phase fluid is sequentially introduced into the heat radiating section 22 via the transfer path 23.

  At the initial stage of the heat recovery, the temperature of the fluid existing in the heat receiving unit 21 is low, and the amount of steam existing in the heat circulation path between the heat receiving unit 21 and the heat radiating unit 22 is small. Therefore, while the temperature of the cooling water of the internal combustion engine 1 is lower than the first target temperature, that is, the internal pressure of the transfer path 23 is lower than the first determination reference value, the drive unit 32 moves the flow control member 31 to the first level shown in FIG. The position is fixed. The first target temperature is set to a value that allows for an appropriate margin based on, for example, 15 ° C., and the first determination reference value is set to have an appropriate correlation with the first target temperature.

  At this time, all of the fluid sent from the transfer path 23 enters the cylindrical portion of the flow control member 31 and is then discharged from the plurality of through holes 31 b in the bottom portion of the flow control member 31. The discharged fluid passes through the small diameter portion 26b relatively quickly and returns to the heat receiving portion 21 from the reflux path 24.

  In the process in which the fluid passes through the small diameter portion 26b as described above, the heat of the fluid is transmitted from the entire inner peripheral surface of the small diameter portion 26b to the cooling water in the hollow portion 26d of the case body 26. In this case, the entire inner peripheral surface of the small-diameter portion 26b of the case body 26 is a heat exchange region, but this heat exchange region is approximately half the axial direction of the center hole of the case body 26, and therefore the effective heat exchange area is small. I can say that.

  Thereby, the quantity which the gaseous fluid in the thermal radiation part 22 passes to the heat receiving part 21 without condensing increases. In other words, since the recirculation amount of the liquid-phase fluid from the heat radiating unit 22 to the heat receiving unit 21 is reduced, a high-temperature gas-phase fluid is quickly filled in the heat circulation path between the heat receiving unit 21 and the heat radiating unit 22. Thus, since the ambient temperature in the heat receiving part 21 becomes high, the heat recovery by the heat receiving part 21 can be performed efficiently.

  Thus, as the amount of heat recovered by the heat receiving portion 21, that is, the amount of evaporation of the liquid-phase fluid in the heat receiving portion 21 gradually increases, the fluid introduced from the heat receiving portion 21 to the heat radiating portion 22 via the transfer path 23 is increased. The temperature of the cooling water of the internal combustion engine 1 increases gradually. Therefore, when the temperature of the cooling water of the internal combustion engine 1 is equal to or higher than the first target temperature, that is, the internal pressure of the transfer path 23 is equal to or higher than the first determination reference value, the drive unit 32 detects this and the flow control member 31 is moved to the case body 26. The large-diameter portion 26a is pushed into the middle in the axial direction and is arranged at the second position shown in FIG. Then, the fluid introduced from the transfer path 23 into the case main body 26 enters the cylindrical portion of the flow control member 31 and is discharged from the plurality of through holes 31b provided at the bottom of the flow control member 31. Part of the fluid that has entered the cylindrical portion of the member 31 overflows from the opening of the cylindrical portion and flows toward the small diameter portion 26b through the facing gap between the cylindrical portion and the large diameter portion 26a of the case body 26. It becomes like this.

  In this case, the fluid flows so as to contact the entire center hole of the case body 26, that is, both the inner peripheral surface of the large diameter portion 26a and the inner peripheral surface of the small diameter portion 26b. It is transmitted to the cooling water in the hollow portion 26d of the case body 26 through the inner peripheral wall of the portion 26a and the inner peripheral wall of the small diameter portion 26b. That is, it can be said that the effective heat exchange area is large because the inner peripheral surface of the entire central hole of the case body 26 is a heat exchange region.

  Thereby, the temperature rise of the cooling water in the heater flow path 13 is promoted. In addition, at this stage, since a large amount of gas-phase fluid exists in the heat circulation path between the heat receiving portion 21 and the heat radiating portion 22, the gas-phase fluid from the heat receiving portion 21 to the heat radiating portion 22 is in a state. The movement becomes slow, and the heat loss due to the friction of the fluid against the inner wall surface of the transfer path 23 is suppressed. This also enables efficient heat transport.

  In this way, since the heat recovery by the heat receiving part 21 is started up to a state where the heat recovery can be performed efficiently, the heat transfer capacity of the heat radiating part 22 is shifted to a state where the heat exchange capacity is increased. And the warming up of the internal combustion engine 1 can be completed promptly.

  By the way, for example, when the cooling water warm-up of the internal combustion engine 1 is completed, that is, when the cooling water temperature is equal to or higher than the final target temperature, that is, the internal pressure of the transfer path 23 is equal to or higher than the second determination reference value, the drive unit 32 detects this. The flow control member 31 is pushed into the bottom of the large-diameter portion 26a of the case body 26 and is arranged at the third position shown in FIG. The final target temperature is set to a value that allows for an appropriate margin based on a steady temperature (for example, 60 to 80 ° C.) after completion of warm-up of the internal combustion engine 1, and the second determination reference value is the final target temperature. Are set to have an appropriate correlation.

  In this state where the flow control member 31 is disposed at the third position, the inner diameter side region of the inscribed circle of each through hole 31 b contacts the stepped wall surface 26 c in the central hole of the case body 26 at the bottom of the flow control member 31. As a result, the small diameter portion 26b is closed.

  As a result, the fluid introduced into the large-diameter portion 26a cannot flow into the small-diameter portion 26b, so that the fluid is not returned from the reflux path 24 to the heat receiving portion 21 and the heat circulation of the exhaust heat recovery device 20 is stopped. become. Therefore, it is not necessary to heat the cooling water of the internal combustion engine 1 excessively.

  By the way, in the case main body 26, the heat transfer amount or the heat transfer amount Q from the fluid to the cooling water is obtained by the following equation as is well known.

Q = UA (T1-T2)
In the above formula, U is the overall heat transfer coefficient [W / (m ₂ / K)], A is the heat transfer area (m ² ), T 1 is the fluid temperature (K), and T 2 is the heating target (cooling water). Temperature (K). The heat transfer area corresponds to the effective heat exchange area described above.

  From this equation, it can be seen that the heat transfer amount or the heat transfer amount Q changes in proportion to the change of the heat transfer area A. Therefore, it is apparent that the heating capacity of the heating target (for example, cooling water of the internal combustion engine 1) can be controlled by adjusting the effective heat exchange area as described above.

  As described above, in the embodiment to which the present invention is applied, in the exhaust heat recovery apparatus 20 having the loop heat pipe structure, the heat release unit 22 uses the heat release unit 22 after it is quickly started to a state where heat recovery by the heat receiving unit 21 can be performed efficiently. It becomes possible to shift to a state in which the heat exchange capability is increased. This makes it possible to quickly complete the warm-up of the internal combustion engine 1 as a heating target, which is advantageous in reducing emissions during the cold start of the internal combustion engine 1. Further, after the cooling water of the internal combustion engine 1 is warmed up, the heat circulation by the exhaust heat recovery device 20 can be stopped to reduce the burden on the radiator 7.

  Next, another embodiment of the present invention will be described with reference to FIGS. In this embodiment, the object to be heated by the exhaust heat recovery device 20 is the upstream catalyst 5 installed in the exhaust system, and the adjustment mechanism is configured differently from that of the above embodiment.

  The exhaust heat recovery device 20 here is configured to promote the temperature rise of the upstream catalyst 5 by recovering the heat of the exhaust gas discharged from the internal combustion engine 1 and transmitting it to the upstream catalyst 5, for example. is there.

  As shown in FIG. 8, the heat radiating portion 22 in this embodiment has a case 25 having a space inside. The outer shape of the upstream catalyst 5 is cylindrical. The case 25 is attached to the upstream catalyst 5 so that a substantially semicircular region on the outer periphery of the upstream catalyst 5 as a heating target enters the internal space.

  In the internal space of the case 25, a partition wall 43 is provided for dividing the substantially semicircular region into which the upstream catalyst 5 enters into the two chambers 41 and 42 at a position that substantially bisects the circumferential direction. As a result, the volumes of the two chambers 41 and 42 are substantially the same, and a substantially 1/4 region of the outer periphery of the upstream catalyst 5 is present in the two chambers 41 and 42, respectively. The partition wall 43 is provided with a communication hole 43 a for communicating the two rooms 41 and 42.

  A fluid introduction port 44a is provided at a predetermined position of the top plate 44 of the case 25, and the transfer path 23 is connected to the introduction port 44a. In addition, a fluid discharge port 45a is provided at a predetermined position of the bottom plate 45 of the case 25, and the reflux path 24 is connected to the discharge port 45a.

  Such a heat radiating part 22 is provided with an adjustment mechanism for adjusting an effective heat exchange area, that is, a heating capacity. This adjustment mechanism mainly includes a flow control member 31 and a drive unit 32.

  In short, the flow control member 31 is accommodated in the case main body 26 so as to be displaceable, and controls the flow of the fluid introduced into the case main body 26 according to the arrangement position. Specifically, the flow control member 31 has a bottomed cylindrical member, that is, a cup shape, as shown in FIG. The opening of the flow control member 31 is provided with flanges 31a that project outward in the radial direction, and through holes 31b are provided at several locations near the outer periphery of the bottom of the flow control member 31. Yes. Furthermore, one end of a rod-shaped power transmission member 33 is connected to the center of the bottom of the flow control member 31.

  The flow control member 31 is housed so that the opening thereof is linearly displaceable between the top plate 44 and the partition wall 43 in the first chamber 41 on the upper side of the case 25.

  The inner diameter dimension of the inscribed circle inscribed in the plurality of through holes 31 b at the bottom of the flow control member 31 is set larger than the inner diameter dimension of the communication hole 43 a of the partition wall 43. Thereby, the inner diameter side region of the bottom of the flow control member 31 with respect to the inscribed circle can block the communication hole 43a in a state where it is in contact with the outer peripheral edge of the communication hole 43a of the partition wall 43.

  The drive unit 32 is of a self-actuating type that automatically displaces the flow control member 31 in three stages according to preset operating conditions. Although not shown, the self-actuating type drive unit 32 has a known configuration using a diaphragm spring. The other end of the rod-shaped power transmission member 33 connected to the flow control member 31 is connected to the diaphragm spring.

  As the operation of the drive unit 32, the diaphragm spring is elastically deformed from the natural posture by the internal pressure of the transfer path 23, and the power transmission member 33 is linearly pushed and pulled according to the posture change of the diaphragm spring. The flow control member 31 is displaced.

  For example, the flow control member 31 has the first position shown in FIG. 8, that is, the flange portion 31 a of the flow control member 31 when the steam is not present in the transfer path 23, such as when the internal combustion engine 1 is cold started. It arrange | positions in the position contact | abutted to the inner surface of 25 top plates 44. As a result, the temperature of the upstream catalyst 5 gradually increases, but when the internal pressure of the transfer path 23 is equal to or higher than the first determination reference value and lower than the second determination reference value, the flow control member 31 is shown in FIG. When the temperature of the upstream catalyst 5 becomes equal to or higher than the activation temperature and the internal pressure of the transfer path 23 becomes equal to or higher than the second determination reference value, the flow control member 31 is shown in FIG. Arranged in the third position.

  Here, the basic operation at the time of cold start of the internal combustion engine 1 will be described. In short, when the internal combustion engine 1 is cold-started, all of the upstream side catalyst 5, the downstream side catalyst 6, and the cooling water of the internal combustion engine 1 are at a low temperature. Therefore, when the internal combustion engine 1 is started, exhaust gas of 300 to 400 ° C., for example, is discharged from the internal combustion engine 1 through the exhaust manifold 2 to the exhaust pipe 4 so that the two catalysts 5 and 6 are exhausted from the inside. While the temperature is increased, the cooling water is returned to the internal combustion engine 1 through the bypass passage 12 without passing through the radiator 7, so that the warm-up operation is performed.

  During this warm-up operation, the exhaust heat recovery device 20 further heats the upstream catalyst 5 to promote the activation of the upstream catalyst 5.

  A basic operation of the exhaust heat recovery apparatus 20 will be described. That is, when the exhaust gas discharged from the internal combustion engine 1 through the exhaust manifold 2 to the exhaust pipe 4 reaches the heat receiving part 21, the liquid-phase fluid in the heat receiving part 21 is heated by the heat of the exhaust gas and evaporated. Will be.

  This vaporized fluid in the vapor phase is transferred to the heat radiating unit 22 through the transfer path 23. The heat of the gas-phase fluid sent to the heat radiating unit 22 is transmitted to the upstream catalyst 5. As a result, the upstream catalyst 5 is heated from the inside by the exhaust gas and is heated from the outside by the gas phase fluid, so that the temperature increase of the upstream catalyst 5 is promoted. The downstream catalyst 6 is heated by the exhaust gas that is heated as it is purified by the upstream catalyst 5.

  Along with the heat exchange between the high-temperature gas-phase fluid introduced into the heat radiating portion 22 and the upstream catalyst 5, the gas-phase fluid in the heat radiating portion 22 is condensed into a liquid phase. The liquid phase fluid is returned from the reflux path 24 to the heat receiving unit 21. Thereafter, the upstream catalyst 5 is heated by circulating the fluid between the heat receiving unit 21 and the heat radiating unit 22 while performing phase transition.

  Next, the operation of the adjustment mechanism having the above-described configuration will be described.

  First, when the internal combustion engine 1 is cold-started, it is assumed that the temperatures of the two catalysts 5 and 6 are low and no steam exists in the closed loop of the exhaust heat recovery device 20. At this time, the drive part 32 shall be arrange | positioned in the position (1st position shown in FIG. 8) which contacted the top part 44 of the case 25 of the flow control member 31 of the adjustment mechanism.

  Here, the heat receiving unit 21 recovers the heat of the exhaust gas that has passed through the downstream catalyst 6, whereby the liquid-phase fluid present in the heat receiving unit 21 is evaporated. The resulting gas-phase fluid is sequentially introduced into the heat radiating section 22 via the transfer path 23.

  At the initial stage of the heat recovery, the temperature of the fluid existing in the heat receiving unit 21 is low, and the amount of steam existing in the heat circulation path between the heat receiving unit 21 and the heat radiating unit 22 is small. Therefore, while the temperature of the upstream catalyst 5 is lower than the first target temperature, that is, the internal pressure of the transfer path 23 is lower than the first determination reference value, the drive unit 32 moves the flow control member 31 to the first position shown in FIG. Leave it stationary. The first target temperature is set to a value that allows for an appropriate margin based on, for example, 15 ° C., and the first determination reference value is set to have an appropriate correlation with the first target temperature.

  At this time, all of the fluid sent from the transfer path 23 enters the cylindrical portion of the flow control member 31 and is then discharged from the plurality of through holes 31 b in the bottom portion of the flow control member 31. The discharged fluid passes through the communication hole 43 a of the partition wall 43 and enters the lower second chamber 42 relatively quickly, and is returned from the reflux path 24 to the heat receiving unit 21.

  In the process in which the fluid passes through the second chamber 42 as described above, the heat of the fluid is transferred to the upstream catalyst 5 exposed in the second chamber 42. In this case, a region exposed in the second chamber 42 of the case 25 in the upstream catalyst 5 is a heat exchange region, but this heat exchange region is only about a quarter region on the outer periphery of the upstream catalyst 5. Therefore, it can be said that the effective heat exchange area is small.

  Thereby, the quantity which the gaseous fluid in the thermal radiation part 22 passes to the heat receiving part 21 without condensing increases. In other words, since the recirculation amount of the liquid-phase fluid from the heat radiating unit 22 to the heat receiving unit 21 is reduced, a high-temperature gas-phase fluid is quickly filled in the heat circulation path between the heat receiving unit 21 and the heat radiating unit 22. Thus, since the ambient temperature in the heat receiving part 21 becomes high, the heat recovery by the heat receiving part 21 can be performed efficiently.

  Thus, as the amount of heat recovered by the heat receiving portion 21, that is, the amount of evaporation of the liquid-phase fluid in the heat receiving portion 21 gradually increases, the fluid introduced from the heat receiving portion 21 to the heat radiating portion 22 via the transfer path 23 is increased. The temperature of the upstream catalyst 5 increases gradually. Therefore, when the temperature of the upstream catalyst 5 is equal to or higher than the first target temperature, that is, the internal pressure of the transfer path 23 is equal to or higher than the first determination reference value, the drive unit 32 detects this, and the flow control member 31 is moved to the first of the case 25. It is pushed into the middle of the room 41 and placed in the second position shown in FIG. Then, the fluid enters the cylindrical portion of the flow control member 31 and is discharged from the plurality of through holes 31b provided in the bottom portion of the flow control member 31, and one of the fluids that has entered the cylindrical portion of the flow control member 31. The portion overflows from the opening of the cylindrical portion and flows into the first chamber 41, and flows toward the communication hole 43 a side of the partition wall 43.

  In this case, the fluid flows into both the first chamber 41 and the second chamber 42 of the case 25 so as to come into contact with the upstream catalyst exposed to both the chambers 41 and 42, so that the heat of the fluid Is transmitted to the substantially semicircular region of the upstream catalyst 5. That is, it can be said that the effective heat exchange area is large because a substantially half region on the outer periphery of the upstream catalyst 5 is a heat exchange region.

  Thereby, the temperature increase of the upstream catalyst 5 is promoted. In addition, at this stage, since a large amount of gas-phase fluid exists in the heat circulation path between the heat receiving portion 21 and the heat radiating portion 22, the gas-phase fluid from the heat receiving portion 21 to the heat radiating portion 22 is in a state. The movement becomes slow, and the heat loss due to the friction of the fluid against the inner wall surface of the transfer path 23 is suppressed. This also enables efficient heat transport.

  In this manner, since the heat recovery by the heat receiving part 21 is started up in a state where the heat recovery can be performed efficiently, the heat exchange capacity by the heat radiating part 22 is shifted to a state in which the activation of the upstream catalyst 5 is completed promptly. It becomes possible to do.

  By the way, for example, when the activation completion condition of the upstream catalyst 5 is satisfied, that is, when the temperature of the upstream catalyst 5 is equal to or higher than the final target temperature, that is, the internal pressure of the transfer path 23 is equal to or higher than the second determination reference value, Is detected, and the flow control member 31 is pushed into the bottom of the first chamber 41 of the case body 26 and is arranged at the third position shown in FIG. The final target temperature is set to a value that allows for an appropriate margin based on the activation temperature of the upstream catalyst 5 (for example, 400 ° C.), and the second determination reference value has an appropriate correlation with the final target temperature. Is set to have

  Thus, in the state where the flow control member 31 is disposed at the third position, the inner diameter side region of the inscribed circle of each through hole 31 b is brought into contact with the outer peripheral edge of the communication hole 43 a of the partition wall 43 at the bottom of the flow control member 31. As a result, the communication hole 43a is closed.

  As a result, the fluid introduced into the first chamber 41 cannot flow into the second chamber 42, so that the fluid is not returned from the reflux path 24 to the heat receiving unit 21, and the heat circulation of the exhaust heat recovery device 20 is stopped. It will be. Therefore, it is not necessary to heat the upstream catalyst 5 excessively.

  By the way, in the case 25, the heat transfer amount or the heat transfer amount Q from the fluid to the cooling water is obtained by the following equation as is well known.

Q = UA (T1-T2)
In the above equation, U is the overall heat transfer coefficient [W / (m ₂ / K)], A is the heat transfer area (m ² ), T 1 is the fluid temperature (K), and T 2 is the heating target (upstream catalyst) 5) the temperature (K). The heat transfer area corresponds to the effective heat exchange area described above.

  From this equation, it can be seen that the heat transfer amount or the heat transfer amount Q changes in proportion to the change of the heat transfer area A. Therefore, it is apparent that the heating capacity of the heating target (for example, the upstream catalyst 5) can be controlled by adjusting the effective heat exchange area as described above.

  As described above, in the embodiment to which the present invention is applied, in the exhaust heat recovery apparatus 20 having the loop heat pipe structure, the heat release unit 22 uses the heat release unit 22 after it is quickly started to a state where heat recovery by the heat receiving unit 21 can be performed efficiently. It becomes possible to shift to a state in which the heat exchange capability is increased. This makes it possible to quickly activate the upstream catalyst 5 as a heating target, which is advantageous in reducing emissions during the cold start of the internal combustion engine 1. Furthermore, after the upstream side catalyst 5 is activated, it is possible to stop the heat circulation by the exhaust heat recovery device 20 and avoid the deterioration of the purification performance due to the excessive heating of the upstream side catalyst 5.

  In addition, this invention is not limited only to the said embodiment, All the deformation | transformation and application included in the range equivalent to the claim and the said range are possible. Examples are given below.

  (1) In each of the above embodiments, an example is given in which a diaphragm spring is used as the drive unit 32 for displacing the flow control member 31, but the present invention is not limited to this.

  The driving unit 32 can have a known configuration using, for example, a thermostat as a driving source, and can be operated using an appropriate actuator and control device.

  As the actuator, for example, a linear cylinder that directly generates linear driving force can be used, and for example, a configuration in which a motor that generates rotational power and a conversion mechanism that converts the rotational power into linear driving force are combined. It can be. The control device is generally a known ECU (Electronic Control Unit).

This control device starts up heat recovery by the heat receiving portion 21 early by disposing the flow control member 31 at the first position shown in FIGS. 4 and 8 when the internal combustion engine 1 is cold-started. When the temperature of the first cooling water and the upstream catalyst 5) reaches the first target temperature lower than the final target temperature, the flow control member 31 is disposed at the second position shown in FIG. 5 and FIG. When the heat exchange capacity is maximized and the temperature of the heating target reaches the final target temperature, the flow control member 31 is arranged at the third position shown in FIGS. 6 and 10 to stop the excessive heating of the heating target. Can be.

  (2) In the above embodiments, the internal combustion engine 1 is not limited to a gasoline engine, a diesel engine, or other engines. In the case of a diesel engine, the catalysts 5 and 6 can be, for example, DPF (Diesel Particulate Filter), DPNR (Diesel Particulate-NOx Reduction system), or the like.

  In the case of a diesel engine, the upstream catalyst 5 can be a NOx storage reduction catalyst (NSR), and the downstream catalyst 6 can be a NOx selective reduction catalyst (SCR).

  (3) In each of the above embodiments, an example in which two catalysts 5 and 6 are provided is given, but the number of catalysts is not limited, and may be, for example, one or three or more. .

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Exhaust manifold 4 Exhaust pipe 5 Upstream catalyst 6 Downstream catalyst 13 Heater flow path (external flow path)
DESCRIPTION OF SYMBOLS 20 Waste heat recovery apparatus 21 Heat receiving part 22 Heat radiating part 23 Transfer path 24 Reflux path 25 Case of heat radiating part 26 Case main body 26a Large diameter part of central hole of case 26b Small diameter part of central hole of case 26c Step wall surface in case 26d Case Hollow part 26e Partition wall 27 of hollow part Joint cover 31 Flow control member 32 Drive part 33 Power transmission member

Claims (3)

A heat receiving part provided in the exhaust passage of the internal combustion engine for evaporating the internal fluid with exhaust heat, and heat dissipation for receiving the fluid evaporated in the heat receiving part and exchanging heat between the fluid and the object to be heated An exhaust heat recovery apparatus having a loop heat pipe structure including a transfer section for transferring a fluid from the heat receiving section to the heat radiating section, and a return path for returning the fluid from the heat radiating section to the heat receiving section. There,
The heat radiating part is provided with an adjusting mechanism for adjusting the effective heat exchange area between the fluid and the heating target by controlling the flow of the fluid introduced ,
The heat dissipating part is provided in a state in which heat can be exchanged with the heating target and has a case to which the transfer path and the reflux path are connected.
The adjustment mechanism is housed in the case so as to be displaceable, and a flow control member for controlling the flow of fluid introduced into the case according to the arrangement position thereof, and for displacing the flow control member Including a drive unit,
When the temperature of the heating target is lower than the first target temperature set lower than the final target temperature, the driving unit moves the fluid introduction position from the transfer path into the case to the transfer path connecting portion side with respect to the case. Placing the flow control member in a first position approaching
When the temperature of the heating target is equal to or higher than the first target temperature and lower than the final target temperature, the fluid introduction position from the transfer path into the case is moved to the second position away from the transfer path connecting portion side with respect to the case. Arrange the control members,
The exhaust heat recovery apparatus , wherein the flow control member is arranged at a third position to stop the fluid introduction to the case or the fluid discharge from the case when the temperature of the heating target is equal to or higher than a final target temperature. . The exhaust heat recovery apparatus according to claim 1,
The exhaust heat recovery apparatus according to claim 1, wherein the drive unit is configured to automatically displace the flow control member in accordance with preset operating conditions . The exhaust heat recovery apparatus according to claim 1 ,
The exhaust heat recovery apparatus according to claim 1, wherein the drive unit is configured to displace the flow control member using an actuator or a control device in accordance with preset operating conditions .

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