JP5304450B2 - Internal combustion engine warm-up device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly cope with a time when requiring to reheat cooling water by exhaust heat after heating the cooling water of an internal combustion engine 1 by the exhaust heat when necessary, in a warm-up device for raising the temperature of the cooling water of the internal combustion engine 1 by collecting the exhaust heat of the internal combustion engine 1 by an exhaust heat collecting device 20 of a loop type heat pipe structure. <P>SOLUTION: An external flow passage 13 for returning the cooling water of the internal combustion engine 1 by taking out once to the outside has a heat exchange area 13a, a bypass passage 14 and a bypass control valve 15. The exhaust heat collecting device 20 is formed as the loop type heat pipe structure including a heat receiving part 21 arranged in an exhaust passage 4 of the internal combustion engine 1 and evaporating an inside fluid by the exhaust heat and a heat radiating part 22 attached to a heat exchange area 13a separated from the heat receiving part 21 and exchanging heat between the fluid and the cooling water in the heat exchange area 13a by receiving the fluid evaporated by the heat receiving part 21, and a fluid circulating passage (24) is provided with a circulation control valve 25 for controlling a circulation flow rate. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a warming-up apparatus for recovering exhaust heat of an internal combustion engine and raising the temperature of cooling water of the internal combustion engine with an exhaust heat recovery apparatus having a loop heat pipe structure.

  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 and used to promote warm-up operation of the internal combustion engine or to promote catalyst activation. It is known (see Patent Documents 1 and 2).

  In the conventional example according to Patent Document 1, an exhaust pipe portion 130 is provided downstream of the catalytic converter 12 in the exhaust pipe 11 of the internal combustion engine 10, and a water tank 140 is stacked on the exhaust pipe portion 130. The heat pipe 110 is provided across the tank 140, and the cooling water flow path 30 of the internal combustion engine 10 is connected to the water tank 140.

  In this conventional example, as shown in the abstract, a valve 31 is provided on the cooling water inflow side to the water tank 140 in the cooling water flow path 30, and the valve 31 is provided when it is desired to transport the exhaust heat to the cooling water. By closing, the inflow of the cooling water to the water tank 140 is stopped.

  The conventional example according to Patent Document 2 includes an evaporation unit 110 that evaporates an internal fluid by exhaust heat of the internal combustion engine 10, a condensing unit 130 that cools the evaporated fluid with cooling water of the internal combustion engine 10, and an evaporation unit 110. A loop heat pipe 101 including a communication unit 161 that communicates with the condensing unit 130 is included.

  In this conventional example, as shown in paragraphs 0087 and 0090 of the specification, when the valve mechanism 150 is provided on the downstream side of the condensing unit 130 and the internal pressure Pi of the heat pipe 101 exceeds the valve closing pressure, the valve mechanism The valve body 155 of 150 is closed so that the condensed water is not recirculated to the evaporating unit 110 and the recovery of the exhaust heat is stopped.

  The conventional exhaust heat recovery apparatuses according to Patent Documents 1 and 2 each have a configuration in which the evaporation section and the condensation section are integrated side by side.

JP 2007-46469 A JP 2008-51479 A

  In the conventional examples according to Patent Documents 1 and 2, since the evaporation unit and the condensing unit are integrated side by side, the internal combustion engine is located up to the position where the condensing unit is installed in the vicinity of the exhaust passage of the internal combustion engine. It is necessary to extend the cooling water outlet channel.

  That is, from the viewpoint of recovering the exhaust heat, it is preferable to install the evaporation section at this position because the downstream side of the exhaust passage is the highest temperature in the exhaust passage. In this case, the evaporation section as described above is preferable. Therefore, it is necessary to extend the cooling water outlet flow path attached to the condensing part longer than the contiguous relation between the condensing part and the condensing part. For this reason, there is a concern that the piping of the cooling water take-out flow path and the reflux flow path becomes complicated and that the amount of cooling water used needs to be increased.

  Furthermore, in the conventional example according to Patent Document 1, there is no technical idea of controlling the circulation amount of the working medium between the evaporation unit and the condensation unit, and naturally, a valve for controlling the circulation amount is also provided. Absent.

  Further, in the conventional example according to Patent Document 2, in order to avoid excessive heating of the cooling water by the heat of the exhaust gas, the condensed water from the condensing unit to the evaporating unit is closed by closing the valve mechanism 150. Although the recirculation is prevented, the cooling water of the internal combustion engine always flows through the condensing part. For this reason, it is impossible to store heat in the exhaust heat recovery apparatus, and there is no technical idea to do so.

  By the way, in Japanese Patent Application Laid-Open No. 2008-38827 (Reference Example 1), in an apparatus that directly exchanges heat between exhaust gas and cooling water, the cooling water taken out from the internal combustion engine is circulated through the collector 4. It is possible to selectively secure a path and a path that prevents the cooling water taken out from the internal combustion engine from flowing through the collector 4. For this switching, a bypass pipe 17 for bypassing the recovery device 4 is provided in the cooling water take-out passage, and a flow path switching valve V1 is provided in the bypass pipe 17.

  Japanese Patent Laid-Open No. 2008-231942 (Reference Example 2) discloses that the cooling water is circulated from the exhaust heat recovery unit 150 to the engine 100 in an apparatus that directly exchanges heat between the exhaust gas and the cooling water. A flow rate control mechanism 300 is provided in the path, and the cooling water flow rate by the flow rate control mechanism 300 is not limited when the cooling water in the reflux path is at a low temperature, and exhaust heat recovery is performed. It is disclosed that when it rises, the exhaust water heat recovery is not performed by limiting the cooling water flow rate.

  However, since the reference examples 1 and 2 are not exhaust heat recovery devices having a loop heat pipe structure, the premise configuration is different from that of the present invention. Moreover, in the exhaust heat recovery device of the loop heat pipe structure, there is also a technical idea of controlling the circulation amount of the fluid between the evaporation unit (heat receiving unit) and the condensing unit (heat radiating unit) and a configuration for realizing it. Absent. Therefore, of course, the technical idea of controlling the fluid circulation amount of the exhaust heat recovery device in association with the circulation amount of the cooling water of the internal combustion engine is not seen.

  In view of such circumstances, the present invention provides a warm-up device for recovering exhaust heat of an internal combustion engine and raising the temperature of cooling water of the internal combustion engine with an exhaust heat recovery device having a loop heat pipe structure. An object of the present invention is to make it possible to quickly cope with the necessity of reheating the cooling water with exhaust heat after the cooling water of the internal combustion engine can be heated with exhaust heat.

An internal combustion engine warm-up device according to the present invention includes an external flow path that temporarily takes out and returns the cooling water of the internal combustion engine, and recovers exhaust heat of the internal combustion engine to cool water in a heat exchange region of the external flow path. And an exhaust heat recovery device for transmission. The external flow path is provided with a bypass path for bypassing the heat exchange region and a bypass control valve for controlling the amount of cooling water flowing into the bypass path. The exhaust heat recovery device is provided in an exhaust passage of an internal combustion engine and is attached to a heat receiving portion for evaporating an internal fluid with exhaust heat, and is attached to a heat exchange region of the external flow channel separated from the heat receiving portion. A heat dissipating part for receiving the fluid evaporated in the heat receiving part and exchanging heat between the fluid and the cooling water flowing through the heat exchanging region; and the heat dissipating the vapor-phase fluid evaporated in the heat receiving part. a transfer path for transferring the parts, is a loop heat pipe structure including a circulation path for the with the heat exchange in the heat radiating portion condensed by a liquid phase form of the fluid returned to the heat receiving portion, the return A circulation control valve for controlling the amount of fluid returned from the heat radiating unit to the heat receiving unit is provided in the path . The bypass control valve is provided at an upstream connection portion of the bypass path with respect to the external flow path, and flows only in the heat exchange path for allowing cooling water to flow only in the heat exchange region of the external flow path. This is a three-way valve for selectively securing the bypass path .

  The exhaust heat recovery device having a loop heat pipe structure is one that repeats exhaust heat recovery and heat dissipation by circulating a fluid between a heat receiving portion and a heat dissipation portion while causing phase transition.

  And if each opening degree of a circulation control valve and a bypass control valve is controlled and linked, for example, the process for positively heating the cooling water in the external flow path by the exhaust heat recovery device, and the external In the fluid circulation path of the exhaust heat recovery device, the processing for storing heat in the exhaust heat recovery device while the cooling water in the flow path is not heated, the processing for stopping the heat storage in the exhaust heat recovery device, Any one of the processes for preventing the components of the exhaust heat recovery apparatus from being damaged due to excessive increase in internal pressure can be executed as necessary.

  First, for example, when the internal combustion engine is cold-started and the exhaust heat is used to promote the warm-up operation of the internal combustion engine, the bypass control valve does not flow cooling water through the bypass path, but only flows through the heat exchange region. Secure the path (heat exchange path) to be opened and open the circulation control valve.

  As a result, the liquid fluid in the heat receiving portion is evaporated by the exhaust heat and transferred to the heat radiating portion, and the heat of the gas phase fluid in the heat radiating portion is taken out from the internal combustion engine and flows through the heat exchange region of the external flow path. Since it is transmitted to the cooling water, the temperature rise of the cooling water is promoted.

  Further, for example, when the cooling water of the internal combustion engine is heated to the required temperature and the warm-up operation is finished, a path (bypass path) in which the cooling water is flowed only through the bypass path by the bypass control valve and is not passed through the heat exchange region. And open the circulation control valve.

  As a result, although the exhaust heat is recovered by the heat receiving portion and the circulation of the fluid is continued, the heat of the heat radiating portion is not transmitted to the cooling water of the internal combustion engine, so that the cooling water of the internal combustion engine can be heated more than necessary. As a result, heat can be stored in the fluid circulation path in the exhaust heat recovery apparatus. Therefore, when the cooling water is reheated later by the exhaust heat recovery apparatus, the heat stored in the fluid circulation path can be used immediately, and the responsiveness is improved.

  Furthermore, when the heat storage of the exhaust heat recovery device becomes sufficient during the warm operation of the internal combustion engine, a path (bypass path) that does not allow the coolant to flow only through the bypass path and flow through the heat exchange area by the bypass control valve. Secure the circulation control valve.

As a result, the liquid-phase fluid condensed in the heat radiating section is not returned to the heat receiving section, and the heat receiving section is in an empty state and steam cannot be sent to the heat radiating section. This state is a state in which exhaust heat recovery is stopped. Therefore, although the heat remaining in the heat radiating portion is transferred to the cooling water remaining in the heat exchange path of the external flow path, the residual heat disappears with the passage of a predetermined time, and therefore remains in the heat exchange path. Cooling water will not boil.

  In addition, when the heat storage of the exhaust heat recovery device becomes excessive during the warm operation of the internal combustion engine, for example, a path (heat) for circulating the cooling water only in the heat exchange area without flowing the cooling water through the bypass path by the bypass control valve. (Replacement path) is secured and the circulation control valve is closed.

  As a result, the cooling water flows without remaining in the heat exchange region of the external flow path. On the other hand, since the liquid-phase fluid condensed in the heat radiating part of the exhaust heat recovery apparatus is not returned to the heat receiving part, the heat receiving part becomes empty and cannot send steam to the heat radiating part. For this reason, the cooling water flowing through the heat exchange path of the external flow channel takes away the heat remaining in the heat radiating portion over a predetermined period, so that the heat radiating portion is cooled. Along with this, the internal pressure of the exhaust heat recovery device is lowered, and the components of the exhaust heat recovery device are not damaged by heat. In addition, the cooling water flowing through the heat exchange area of the external flow path only takes away the residual heat in the heat radiating section, and after the residual heat disappears, the cooling water is not heated, so a load on the radiator attached to the internal combustion engine is necessary. It is possible to avoid such an increase.

  Preferably, the heat radiating portion is supported by a catalyst provided in the exhaust passage via a support member having excellent thermal conductivity.

  In this configuration, the heat radiating portion and the catalyst are thermally conducted to each other via the support member. Thereby, for example, when the heat radiating portion is at a higher temperature than the catalyst, the heat of the heat radiating portion can be transmitted to the catalyst, and the temperature of the catalyst is increased. On the other hand, when the temperature of the catalyst is higher than that of the heat radiating portion, the heat of the catalyst can be transmitted to the heat radiating portion, the catalyst is cooled, and heat is radiated when heat is stored in the heat radiating portion. The gas-phase fluid in the section is not condensed.

  Preferably, when the internal combustion engine is cold-started, the bypass control valve secures a heat exchange path that allows only the heat exchange region to flow without flowing cooling water through the bypass path, and the circulation control valve Processing to release is performed.

  Preferably, when the warm-up operation of the internal combustion engine is completed, the bypass control valve secures a bypass path that does not flow cooling water only through the bypass path and flows through the heat exchange path, and opens the circulation control valve. Processing is performed.

  Preferably, when the heat storage of the exhaust heat recovery device reaches a target during the warm operation of the internal combustion engine, a bypass path that prevents the coolant from flowing only through the bypass path and flowing through the heat exchange path with the bypass control valve. A process for securing the circulation control valve is performed while securing the circulation control valve.

  Preferably, when the heat storage of the exhaust heat recovery device becomes excessive during the warm operation of the internal combustion engine, the heat that causes only the heat exchange region to flow without flowing the cooling water through the bypass passage by the bypass control valve. A process for securing the exchange path and closing the circulation control valve is performed.

  Preferably, each of the bypass control valve and the circulation control valve is an actuator drive type having an actuator as a drive source of the valve body, and further includes a control device for controlling the actuator according to a preset condition.

  According to this configuration, the control device, for example, when the cooling water of the internal combustion engine needs to be heated by the exhaust heat recovery device, when the heat is stored in the exhaust heat recovery device, and when the heat storage of the exhaust heat recovery device is performed. In the case where it becomes excessive, the bypass control valve and the circulation control valve can be appropriately operated as necessary.

  The present invention relates to a warm-up device for recovering the exhaust heat of an internal combustion engine and raising the temperature of the coolant of the internal combustion engine with an exhaust heat recovery device having a loop heat pipe structure. It becomes possible to respond quickly when it becomes necessary to reheat the cooling water with the exhaust heat after making it possible to heat with the exhaust heat.

1 is a schematic configuration diagram showing an embodiment of a warm-up device for an internal combustion engine according to the present invention. It is sectional drawing which shows the specific structure of the waste heat recovery apparatus in FIG. It is a flowchart used for operation | movement description of the warming-up apparatus of FIG.

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

  1 to 3 show an embodiment of the present invention. With reference to FIG. 1, a schematic configuration of a warm-up device for an internal combustion engine mounted on a vehicle 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.

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

  This exhaust heat recovery device 20 is configured to recover the heat of the exhaust gas discharged from the internal combustion engine 1 and use it, for example, for promoting the temperature rise of the cooling water of the internal combustion engine 1. It has a loop heat pipe structure including the section 22, the transfer path 23, and the 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 portion 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 take in heat as vaporization heat. It is configured.

  Specifically, the heat receiving portion 21 is installed in a direction perpendicular to the exhaust gas passage direction with respect to the exhaust pipe 4. For example, as shown in FIG. 2, the upper tank 21 a and the lower tank 21 b are connected to each other. .. Are communicated by a plurality of fluid passages 21c... And corrugated fins 21e... Are provided in the exhaust passage 21d between the adjacent fluid passages 21c.

  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 dissipating unit 22 is attached to the internal combustion engine 1, receives the fluid converted into steam by the heat receiving unit 21, and transmits the heat of the fluid to a heating target (for example, cooling water of the internal combustion engine 1). The fluid is condensed after heat transfer and returned to the heat receiving unit 21.

  Specifically, the heat radiating section 22 has a configuration in which the downstream end of the transfer path 23 and the upstream end of the reflux path 24 are connected to a case 22a whose inside is sealed, and the internal space of the case 22a includes A partial region of the external flow path 13 is inserted.

  The external flow path 13 is for taking out the cooling water of the internal combustion engine 1 and returning it, and is connected to the upstream side of the cooling water take-out path 8 and the upstream side of the water pump 10 in the cooling water recirculation path 9. Has been.

  A region inserted in the case 22a of the heat radiating portion 22 in the external flow path 13 is referred to as a heat exchange region 13a. On the outer periphery of the heat exchange region 13a, fins 13b for expanding the heat exchange area are provided.

  The external flow path 13 is provided with a bypass path 14 and a bypass control valve 15. The bypass path 14 bypasses the heat exchange region 13 a in the external flow path 13. The bypass control valve 15 is installed at an upstream connection portion of the bypass path 14 with respect to the external flow path 13, and if necessary, a path for circulating the cooling water only to the heat exchange region of the external flow path (in FIG. 1). (Refer to arrow X, hereinafter referred to as a heat exchange path) and a path (see arrow Y in FIG. 1, hereinafter referred to as a bypass path) that is circulated only in the bypass path 14. The bypass control valve 15 is, for example, an electromagnetic three-way valve, and is configured to control an actuator as a drive source of the valve body by the control device 30.

  Further, a heater unit 16 is provided on the downstream side of the bypass passage 14 in the external passage 13. Although not shown in detail, the heater unit 16 is used to introduce a heater core as a heat source for heating the vehicle interior using the heat of the cooling water and air heated by the heater core into the vehicle interior. This is a configuration that includes a blower fan.

  The heat radiation part 22 is supported by the upstream catalyst 5 via a bracket 27 as a support member. The bracket 27 is made of a material having high thermal conductivity (for example, stainless steel), and thereby heat exchange is possible between the heat radiating portion 22 and the upstream catalyst 5.

  The transfer path 23 is a pipe for communicating and 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 vapor-phase fluid evaporated in the heat receiving part 21 to the heat radiating part 22. is there.

  The reflux path 24 is a pipe for communicating and 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.

  A circulation control valve 25 is provided near the heat radiating portion 22 in the reflux path 24. The circulation control valve 25 is switched between an open state that allows fluid flow from the heat radiating unit 22 to the heat receiving unit 21 and a closed state that prohibits it as necessary. Although not shown in detail, the circulation control valve 25 is configured such that, for example, a drive source for driving the valve body is an actuator, such as an electromagnetic valve, and the actuator is controlled by the control device 30. .

  Note that the amount of fluid returned from the heat radiating unit 22 to the heat receiving unit 21, that is, the amount of fluid circulation in the closed loop of the exhaust heat recovery device 20 is adjusted by controlling the opening degree of the circulation control valve 25 by the control device 30 in a stepless manner. It is also possible to set so as to.

  The control device 30 is generally a known ECU (Electronic Control Unit), and is connected to a central processing unit (CPU), a program memory (ROM), a data memory (RAM), and a backup memory (connected to each other via a bidirectional bus). (Nonvolatile RAM) and the like.

  Next, the 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 via the transfer path 23. The heat of the gas-phase fluid sent to the heat radiating unit 22 is transmitted to the cooling water in the heat exchange region 13a of the external flow path 13 to heat the cooling water. By the heat exchange between the gas-phase fluid in the heat radiating portion 22 and the cooling water in the external flow path 13, the gas-phase fluid in the heat radiating portion 22 is condensed.

  The condensed liquid phase fluid is returned from the reflux path 24 to the heat receiving unit 21. Thereafter, the cooling water of the internal combustion engine 1 is heated by circulating the fluid between the heat receiving unit 21 and the heat radiating unit 22 while performing phase transition.

  Next, processing of the control device 30 according to the operation of the internal combustion engine 1 will be described with reference to the flowchart of FIG. The flowchart of FIG. 3 is entered as the internal combustion engine 1 is started.

  In general, when the internal combustion engine 1 is cold-started, exhaust gas of, for example, 300 to 400 ° C. is discharged from the internal combustion engine 1 through the exhaust manifold 2 to the exhaust pipe 4, and the two catalysts 5 and 6 are inside. While the temperature of the exhaust water is raised from the exhaust gas, the cooling water is returned to the internal combustion engine 1 via the bypass 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.

On the other hand, in step S1, it is determined whether or not the coolant temperature T _L of the internal combustion engine 1 is _{equal to} or higher than the first threshold value T _LX . Here, it is examined whether or not the internal combustion engine 1 is cold-started, that is, whether or not the cooling water of the internal combustion engine 1 needs to be heated by the exhaust heat recovery device 20.

The first threshold value T _LX is set to the cooling water temperature during the warm operation of the internal combustion engine 1. The cooling water temperature _TL of the internal combustion engine 1 is measured by a water temperature sensor 31 installed in the vicinity of the most downstream side of the external flow path 13.

For example, when the coolant temperature T _L is less than the first threshold value T _LX , the internal combustion engine 1 needs to be warmed up, so a negative determination is made in step S1, and in step S2, the bypass control valve 15 After securing the heat exchange path (see arrow X in FIG. 1), the circulation control valve 25 is opened.

  Thereby, the cooling water taken out from the internal combustion engine 1 to the external flow path 13 flows only in the heat exchange region 13a, and the heat circulation of the exhaust heat recovery device 20 is performed. At this time, the exhaust heat recovered by the heat receiving unit 21 of the exhaust heat recovery device 20 is transmitted from the heat radiating unit 22 to the cooling water flowing through the heat exchange region 13a, and the cooling water is heated. Machine operation will be promoted.

After step S2, the process returns to step S1, and steps S1 and S2 are repeated until the coolant temperature T _L becomes _{equal to} or higher than the first threshold value T _LX .

On the other hand, for example, when the cooling water temperature T _L is equal to or higher than the first threshold value T _LX , for example, when the warm-up operation of the internal combustion engine 1 is finished, it is not necessary to heat the cooling water any more. In step S3, the bypass control valve 15 secures a bypass path (see arrow Y in FIG. 1), and then the circulation control valve 25 is opened.

  Thereby, the cooling water taken out from the internal combustion engine 1 to the external flow path 13 flows only into the bypass path 14, and the heat circulation of the exhaust heat recovery device 20 is continued. At this time, since the heat of the heat radiating portion 22 cannot be transmitted to the cooling water, it becomes possible to avoid heating the cooling water more than necessary, and in each of the components 21 to 24 of the exhaust heat recovery device 20. In this state, a high-temperature gas-phase fluid is filled, that is, heat is stored.

  If it is set in such a heat storage state, when it becomes necessary to reheat the cooling water in the external flow path 13 later in the exhaust heat recovery device 20, the heat stored in the heat radiation part 22 can be used immediately. As a result, the responsiveness is improved, such as the rise loss of the heat recovery operation of the exhaust heat recovery apparatus 20 can be reduced, which is preferable.

  However, in the heat storage state as described above, the cooling water remaining in the heat exchange region 13a of the external flow path 13 may be excessively heated and boiled, and the internal pressure of the exhaust heat recovery device 20 may be increased. Will gradually rise.

Therefore, after step S3, in subsequent step S4, it is determined whether or not the fluid temperature T _C in the heat receiving portion 21 is _{equal to} or higher than the second threshold value T _CX1 . Here, it is examined whether or not the heat storage of the exhaust heat recovery apparatus 20 that has been in the heat storage state in step S3 is unnecessary.

The second threshold value T _CX1 is set to a temperature at which the heat necessary for heat exchange with the cooling water when the exhaust heat recovery device 20 _reheats the cooling water of the internal combustion engine 1 is sufficiently stored. This temperature is set by conducting various experiments in advance. The measurement of fluid temperature T _C in the heat receiving unit 21 is configured to perform the temperature sensor 32 installed in the upper tank 21a of the heat receiving section 21.

For example, when the fluid temperature T _C is less than the second threshold value T _CX1 , the heat storage of the exhaust heat recovery device 20 is insufficient, so a negative determination is made in Step S4 and the process returns to Step S1.

On the other hand, when the fluid temperature T _C is equal to or higher than the second threshold value T _CX1 , the heat storage of the exhaust heat recovery device 20 is sufficient, so an affirmative determination is made in Step S4 and the process proceeds to the subsequent Step S5.

  In step S5, the bypass control valve 15 secures the bypass path Y and then closes the circulation control valve 25.

  As a result, the cooling water does not flow in the heat exchange region 13a of the external flow path 13, but flows only in the bypass path 14. On the other hand, since the liquid-phase fluid condensed in the heat radiating unit 22 of the exhaust heat recovery apparatus 20 is not returned to the heat receiving unit 21, the heat receiving unit 21 becomes empty and cannot send steam to the heat radiating unit 22. Therefore, although the heat remaining in the heat radiating portion 22 is transferred to the cooling water remaining in the heat exchange path 13a of the external flow path 13, the residual heat disappears with the elapse of a predetermined time, so that the heat exchange path 13a The cooling water remaining in the tank can be prevented from boiling.

After step S5, in subsequent step S6, it is determined whether or not the fluid temperature T _C in the heat receiving portion 21 is _{equal to} or higher than the third threshold value T _CX2 . Here, it is examined whether or not the constituent elements of the exhaust heat recovery apparatus 20 in the heat storage state in step S3 may be damaged due to an increase in internal pressure.

The third threshold value T _CX2 is set to a temperature value that has a correlation with the allowable limit pressure of the constituent elements of the exhaust heat recovery apparatus 20. The third threshold value T _CX2 is set so as to have an appropriate margin after grasping beforehand the failure limit pressure of the constituent elements of the exhaust heat recovery apparatus 20 through various experiments. The relationship between the third threshold value T _CX2 and the second threshold value T _CX1 is T _CX2 > T _CX1 . The measurement of fluid temperature T _C in the heat receiving unit 21 is configured to perform the temperature sensor 32 installed in the upper tank 21a of the heat receiving section 21.

For example, when the fluid temperature T _C is less than the second threshold value T _CX2 , the internal pressure of the fluid circulation path of the exhaust heat recovery device 20 has not increased excessively, so a negative determination is made in Step S6, and the Step S1 is reached. Return. In this case, heat storage is continued.

On the other hand, when the fluid temperature T _C is equal to or higher than the second threshold value T _CX2 , the internal pressure of the fluid circulation path of the exhaust heat recovery device 20 is excessively increased. Migrate to

  In this step S7, after the heat exchange path X is secured by the bypass control valve 15, the circulation control valve 25 is closed.

  Accordingly, the cooling water flows without remaining in the heat exchange region 13a of the external flow path 13. On the other hand, since the liquid-phase fluid condensed in the heat radiating unit 22 of the exhaust heat recovery apparatus 20 is not returned to the heat receiving unit 21, the heat receiving unit 21 becomes empty and cannot send steam to the heat radiating unit 22. Therefore, the cooling water flowing through the heat exchange path 13a of the external flow path 13 takes away the heat remaining in the heat radiating part 22 over a predetermined period, so that the heat radiating part 22 is cooled. Along with this, the internal pressure of the exhaust heat recovery device 20 is lowered, and the components of the exhaust heat recovery device 20 are not damaged by heat. Moreover, although the cooling water flowing through the heat exchange region 13a of the external flow path 13 takes away the residual heat in the heat radiating portion 22, the cooling water is not heated after the residual heat is lost, and is thus attached to the internal combustion engine 1. An increase in the load on the radiator 7 more than necessary can be avoided.

  After step S7, the process returns to step S1, and steps S1 to S7 are repeated as necessary.

  By the way, in this embodiment, since the heat radiating portion 22 is supported by the upstream catalyst 5 via the bracket 27 having excellent thermal conductivity, the heat radiating is performed in a situation where the upstream catalyst 5 has not reached the activation temperature. The heat of the portion 22 is conducted to the upstream catalyst 5 through the bracket 27, and the temperature rise of the upstream catalyst 5 can be promoted. On the other hand, when the upstream catalyst 5 is at the activation temperature or higher and the exhaust heat recovery device 20 is in the heat storage state, the heat of the upstream catalyst 5 is dissipated through the bracket 27 contrary to the above. Therefore, it is advantageous in preventing the vapor-phase fluid in the heat radiation part 22 from condensing.

  As described above, in the embodiment to which the present invention is applied, by controlling the circulation control valve 25 and the bypass control valve 15 in association with each other, for example, the cooling water in the external flow path 13 is removed by the exhaust heat recovery device 20. In order to pause processing for positively heating, processing for storing heat in the exhaust heat recovery device 20 while keeping the cooling water in the external flow path 13 unheated, and heat storage in the exhaust heat recovery device 20 One of the above processing and the processing for preventing any damage to the components of the exhaust heat recovery device 20 due to excessive increase in the internal pressure of the fluid circulation path of the exhaust heat recovery device 20 is executed as necessary. It becomes possible to do.

  By appropriately executing these processes, first, the warm-up operation of the internal combustion engine 1 can be promoted. Further, after the internal combustion engine 1 is warmed up, unnecessary heating of the cooling water is stopped so that the burden on the radiator 7 can be reduced. Furthermore, when the cooling water of the internal combustion engine 1 needs to be reheated, the heat of the exhaust heat recovery device 20 can be used quickly. In addition, it is possible to avoid any possible damage due to the heat of the components of the exhaust heat recovery apparatus 20.

  In addition, in this embodiment, since the heat receiving part 21 and the heat radiating part 22 of the exhaust heat recovery apparatus 20 are installed separately from each other, the heat radiating part 22 is installed closer to the internal combustion engine 1. There is no need to construct the external flow path 13 so as to be elongated. Therefore, as in the case where the heat receiving portion 21 and the heat radiating portion 22 are installed close to each other, the piping of the cooling water take-out flow path and the reflux flow path becomes complicated and it is necessary to increase the amount of cooling water used. It is possible to avoid problems such as occurrence.

  Moreover, in the said embodiment, since the heat radiating part 22 and the heat receiving part 21 are attached to the exhaust pipe 4 by installing the heat radiating part 22 downstream from the spherical joint 3, the vehicle main body is connected to the exhaust pipe 4. Even when a vibration unrelated to the heat is generated, the heat radiating portion 22 and the heat receiving portion 21 are not displaced relatively, but are displaced synchronously. As a result, bending stress does not act on the root of 24. Therefore, the exhaust heat recovery device 20 is less likely to cause fatigue damage over time, and it is possible to achieve a longer life, and the thickness and outer diameter size of the transfer path 23 and the reflux path 24 are increased. Measures such as increasing the rigidity or forming the transfer path 23 and the reflux path 24 with flexible pipes are not necessary.

  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 the above embodiment, an example is given in which the bypass control valve 15 is a three-way valve, but the present invention is not limited to this. For example, in the bypass passage 14 and the external passage 13, on-off valves can be installed at a total of two locations between the upstream connection portion of the bypass passage 14 and the heat exchange region 13 a.

  In this case, the heat exchange path X can be secured by closing the on / off valve of the bypass path 14 and opening the on / off valve on the heat exchange flow path side. On the other hand, the bypass path Y can be secured by opening the on-off valve of the bypass path 14 and closing the on-off valve on the heat exchange channel side.

  (2) In the above embodiment, for the flow control valve 25, for example, a drive source for driving a valve element such as an electromagnetic valve is used as an actuator, and this actuator is controlled by the control device 30. Yes. However, the present invention is not limited to this, and the flow control valve 25 can be replaced with a self-actuating valve device. This self-actuated valve device is known to use, for example, a thermostat or a diaphragm spring as a drive source for the valve body. This drive source automatically operates according to preset conditions to open and close the valve body. Make it work.

  For example, in a heat-sensitive type valve device that uses a thermostat as a drive source, the valve body is automatically opened when it is sensed that the temperature in the reflux path 24 of the exhaust heat recovery device 20 is lower than an appropriate set temperature. The valve body is automatically closed when it is detected that the temperature is equal to or higher than the set temperature.

  In a pressure-sensitive type valve device that uses a diaphragm spring as a drive source, when an internal pressure that correlates with a state in which the temperature in the reflux path 24 of the exhaust heat recovery device 20 is lower than an appropriate set temperature is detected, the diaphragm is detected. While the spring is in a natural state and the valve body is automatically opened, the diaphragm spring is elastically deformed when an internal pressure that correlates with a state where the temperature is equal to or higher than the set temperature is detected. The valve body is automatically closed.

  When such a self-actuated valve device is used as the flow control valve 25, an actuator (not shown) or a control device (30) as a drive source for driving the valve body, and detection means for information to be sensed (Temperature sensor or the like) is unnecessary, which is advantageous in reducing the equipment cost. The flow rate control valve 25 is a flow rate that can arbitrarily adjust the valve opening degree, that is, the recirculation amount of the liquid-phase fluid from the heat radiating unit 22 to the heat receiving unit 21 in addition to the open / close valve that switches between full open and full close. It is also possible to use a regulating valve.

  (3) In the above embodiment, an example is given in which the present invention is applied to a general vehicle on which only the internal combustion engine 1 is mounted, but the present invention is not limited to this. For example, the present invention can be applied to a hybrid vehicle equipped with the internal combustion engine 1 and an electric motor.

  In a hybrid vehicle, for example, when the vehicle is stopped, an idle stop process for stopping the internal combustion engine 1 is performed to improve fuel consumption. During such an idle stop process, the internal combustion engine 1 is started when the coolant temperature of the internal combustion engine 1 falls below an appropriate threshold value. In that case, when the internal combustion engine 1 is started during the idling stop process as the temperature of the cooling water in the internal combustion engine 1 decreases, the fuel consumption is reduced accordingly.

However, when the present invention is applied to such a hybrid vehicle, as described in the above embodiment, in the loop of the flowchart of FIG. 3, the control device 30 determines that the cooling water temperature T _L is the first threshold value T _{LX in} step S1. When it is determined that the temperature has become less, the exhaust heat recovery device 20 is used to heat the cooling water to raise the temperature. For this reason, during the idling stop process, it is not necessary to start the internal combustion engine 1 even if the cooling water temperature decreases, and it is possible to prevent wasteful fuel consumption. Therefore, if the present invention is applied to a hybrid vehicle, it becomes possible to prevent a reduction in fuel consumption as much as possible.

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

  (5) In the said embodiment, the internal combustion engine 1 is not limited to a gasoline engine, a diesel engine, and another engine. 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).

1 Internal combustion engine
2 Exhaust manifold
4 Exhaust pipe
5 Upstream catalyst
6 Downstream catalyst
7 Radiator
8 Cooling water outlet
9 Cooling water return path
13 External flow path
13a Heat exchange area of external flow path
14 Bypass
15 Bypass control valve
20 Waste heat recovery device
21 Heat receiving part
22 Heat radiation part
23 Transfer route
24 Return route
25 Circulation control valve
27 Bracket (support member)
30 Control device

Claims (7)

An external flow path for taking out the cooling water of the internal combustion engine and returning it to the outside; and an exhaust heat recovery device for collecting the exhaust heat of the internal combustion engine and transferring it to the cooling water in the heat exchange region of the external flow path,
The external flow path is provided with a bypass path for bypassing the heat exchange region, and a bypass control valve for controlling the amount of cooling water flowing into the bypass path,
The exhaust heat recovery device is provided in an exhaust passage of an internal combustion engine and is attached to a heat receiving portion for evaporating an internal fluid with exhaust heat, and is attached to a heat exchange region of the external flow channel separated from the heat receiving portion. A heat dissipating part for receiving the fluid evaporated in the heat receiving part and exchanging heat between the fluid and the cooling water flowing through the heat exchanging region; and the heat dissipating the vapor-phase fluid evaporated in the heat receiving part. a transfer path for transferring the parts, is a loop heat pipe structure including a circulation path for the with the heat exchange in the heat radiating portion condensed by a liquid phase form of the fluid returned to the heat receiving portion, the return A circulation control valve for controlling the amount of fluid returned from the heat radiating unit to the heat receiving unit is provided in the path ,
The bypass control valve is provided at an upstream connection portion of the bypass path with respect to the external flow path, and flows only in the heat exchange path for allowing cooling water to flow only in the heat exchange region of the external flow path. A warm-up device for an internal combustion engine, characterized in that it is a three-way valve for selectively securing a bypass path . The warm-up device for an internal combustion engine according to claim 1,
The warming-up device for an internal combustion engine, wherein the heat radiating portion is supported by a catalyst provided in the exhaust passage via a support member having excellent thermal conductivity . The warm-up device for an internal combustion engine according to claim 1 or 2,
When the internal combustion engine is cold started, the bypass control valve secures a heat exchange path that allows only the heat exchange area to flow without flowing cooling water through the bypass path, and opens the circulation control valve. is carried out, warming-up system for an internal combustion engine, characterized in that. The warm-up device for an internal combustion engine according to any one of claims 1 to 3,
When the warm-up operation of the internal combustion engine is finished, the bypass control valve is configured to secure a bypass path that does not flow cooling water only through the bypass path and flow through the heat exchange path, and to open the circulation control valve. carried out, warming-up system for an internal combustion engine, characterized in that. The warm-up device for an internal combustion engine according to any one of claims 1 to 4,
When the heat storage of the exhaust heat recovery device reaches the target during the warm operation of the internal combustion engine, the bypass control valve secures a bypass path that does not flow the cooling water only through the bypass path and distribute it to the heat exchange path. A warming-up device for an internal combustion engine , wherein a process for closing the circulation control valve is performed. The warm-up device for an internal combustion engine according to any one of claims 1 to 5,
When the heat storage of the exhaust heat recovery device becomes excessive during the warm operation of the internal combustion engine, a heat exchange path that allows only the heat exchange area to flow without flowing the cooling water to the bypass path with the bypass control valve. A warming-up device for an internal combustion engine characterized in that a process for securing and closing the circulation control valve is performed. The warm-up device for an internal combustion engine according to any one of claims 1 to 6,
Each of the bypass control valve and the circulation control valve is an actuator drive type having an actuator as a drive source of the valve body,
Ru a control device for controlling the actuator in accordance with the conditions set in advance Further, warm-up system for an internal combustion engine, characterized in that.

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