JP2019188863A - Heat pipe device - Google Patents

Abstract

To provide a heat pipe device which can use heat of an exhaust gas for heating with good efficiency.SOLUTION: A heat pipe device 40 can perform heating. The heat pump device comprises a condenser 73 which is provided on an air conditioner 7, an evaporator 25 which is provided on an exhaust pipe 9, and a circulation pipeline 41 which circulates a working liquid. The evaporator 25 has a heat exchange flow path 50 which is so located as to cross flow of exhaust gas. The working liquid, which flows in the heat exchange flow path 50, is heat-exchanged with exhaust gas, whereby the working liquid is vaporized. A reception heat quantity of the working liquid, which flows on a downstream side of the heat exchange flow path 50, becomes less than a reception heat quantity of the working liquid which flows on an upstream side.SELECTED DRAWING: Figure 12

Description

  The disclosed technology relates to a heat pipe device that is installed in a vehicle and can heat a passenger compartment.

  Generally, a heat pipe refers to a tube body whose pressure is reduced and a small amount of hydraulic fluid is sealed. With a heat pipe, the evaporation and condensation of the hydraulic fluid are generated at different sites. By doing so, the hydraulic fluid moves and heat can be transferred. Therefore, unlike the heat pump, the heat pipe does not require a driving force such as a pump for the movement of heat.

  FIG. 1 shows a basic configuration of a heat transfer device (heat pipe device 100) using a heat pipe technology. An exemplary heat pipe device 100 includes an evaporator 101, a condenser 102, and a circulation pipe 103 connecting them. The condenser 102 is disposed at a higher position than the evaporator 101. The circulation pipe 103 is connected to the upper part of each of the evaporator 101 and the condenser 102, and is connected to the lower part of each of the evaporator 101 and the condenser 102. And a second pipe portion 103b for use.

  The inside of the heat pipe device 100 is highly depressurized, and an appropriate amount of hydraulic fluid (aqueous solution, alcohol, refrigerant, etc.) is sealed therein. As a result, the working fluid is stored in the lower part of the evaporator 101 and in the second pipe portion 103b.

  When heat is supplied to the evaporator 101, the working liquid is vaporized by the heat. The vapor of the working fluid generated by vaporization moves to the condenser 102 through the first pipe portion 103a. The vapor of the working fluid that has moved to the condenser 102 is radiated and liquefied by the condenser 102. The liquefied hydraulic fluid moves to the evaporator 101 through the second pipe portion 103b due to the vapor pressure of the hydraulic fluid and the action of gravity. Due to the heat absorption in the evaporator 101 and the heat radiation in the condenser 102, the working fluid circulates through the heat pipe device 100, and heat is transferred.

  As a prior art of heating using a heat pipe technology, there is, for example, Patent Document 1.

  Patent Document 1 discloses a heating device that can be heated immediately by using a heat pipe technology. Specifically, the heating device stores a part of engine cooling water (hot water) at a high temperature in the heat retaining tank 7, and when the temperature of the cooling water is low, heating is performed using the heat of the stored hot water. It is configured to do so. A pre-tank 9 is provided in the warm water channel 8 on the upstream side of the heat retaining tank 7, and the first condensing unit 20 of the heat pipe 17 is installed inside the pre-tank 9. The evaporation part 19 of the heat pipe 17 is installed around the exhaust pipe 18.

  In relation to the present invention, Patent Document 2 discloses a technique for suppressing the evaporation rate of the working fluid in the axial direction from becoming uneven in the evaporator of the heat pipe device.

  Specifically, the evaporator has a cylindrical metal case and a ceramic porous member (wick) housed in the case. The wick is formed in a cylindrical shape with one end sealed, and the working fluid flows into the wick from the other end. The working fluid evaporates as it oozes from the wick that is heated through the case during use.

  In order to equalize the evaporation rate of the working fluid in the axial direction, the thermal resistance between the case and the wick is configured to be different between the upstream side and the downstream side of the working fluid.

Japanese Patent Laid-Open No. 61-295118 JP 2017-227384 A

  In Patent Document 1, the heat of the exhaust gas is used for heating the passenger compartment by using a heat pipe technology. However, since it presupposes a mechanism for heating using the stored hot water heat, the heating device of Patent Document 1 has a large scale and a complicated structure. Moreover, it is necessary to newly install a member dedicated to the heating device. In addition, there are members that require a large space for installation, such as a heat retaining tank.

  Therefore, it is not easy to apply the heating device of Patent Document 1 to an existing automobile. Moreover, in the heating apparatus of Patent Document 1, the heat of the exhaust gas is not directly used for heating, but is used for heating cooling water. Therefore, there is a disadvantage in terms of thermal efficiency.

  Furthermore, in the heating apparatus of Patent Document 1, the heat pipe evaporating part is installed around the exhaust pipe, and therefore the heat exchange efficiency is poor.

  Moreover, in the evaporator of patent document 2, a working fluid passes through the fine hole of a wick, and also a working fluid vaporizes in the process. Thus, when the working fluid passes through the wick, the working fluid experiences a strong flow resistance. Therefore, since the working fluid cannot be smoothly circulated at a low load, the evaporator of Patent Document 2 is also disadvantageous in terms of thermal efficiency.

  An object of the technology disclosed there is to provide a heat pipe device that can efficiently use the heat of exhaust gas for heating.

  The technology disclosed herein relates to a heat pipe device that is installed in a vehicle and can heat a passenger compartment.

  The vehicle is disposed facing an interior of the vehicle interior, an internal combustion engine that generates power of the vehicle, an exhaust pipe that exhausts exhaust gas generated by the internal combustion engine, and blows air into the interior of the vehicle interior An air conditioner. The heat pipe device includes a condenser installed in the air conditioner, an evaporator installed in the exhaust pipe, and a circulation pipe connected to the condenser and the evaporator to circulate the working fluid. . The evaporator has a heat exchange flow path arranged to intersect the flow of exhaust gas.

  Then, the hydraulic fluid flowing through the heat exchange channel is vaporized by exchanging heat with exhaust gas, and the amount of heat received by the hydraulic fluid flowing downstream from the heat exchange channel is upstream of the heat exchange channel. It is comprised so that it may become less than the heat receiving amount of the said hydraulic fluid which flows through the side.

  According to this heat pipe device, the condenser is installed in the air conditioner that blows air into the passenger compartment. An evaporator is installed in an exhaust pipe that discharges high-temperature exhaust gas generated in an internal combustion engine. The condenser and the evaporator are connected by a circulation pipe through which the working fluid circulates. That is, in this heat pipe device, the heat of the exhaust gas can be moved to the air conditioner. Therefore, the passenger compartment can be efficiently heated by directly using the heat of the exhaust gas.

  However, such a heat pipe device has a problem regarding exhaust heat recovery. That is, in recent years, an exhaust treatment device that uses exhaust heat may be installed in the middle of an exhaust pipe. In that case, if the evaporator is disposed upstream of the exhaust treatment device, the function of the exhaust treatment device may be impaired due to heat exchange by the evaporator. Therefore, in that case, the evaporator is disposed in the exhaust pipe downstream of the exhaust treatment device.

  Thereby, the distance from an evaporator to a condenser becomes large, and it becomes easy to radiate heat with circulation piping. This is disadvantageous in terms of thermal efficiency. In addition, when such an exhaust treatment device is disposed upstream of the evaporator, the temperature of the exhaust gas passing through the evaporator may decrease. Thereby, there is a possibility that the heat that can be recovered by the evaporator is insufficient.

  On the other hand, in this heat pipe device, the evaporator that performs heat exchange with the exhaust gas has a heat exchange flow path arranged so as to intersect the flow of the exhaust gas. The hydraulic fluid flows through the heat exchange flow path and exchanges heat with the exhaust gas. Therefore, the hydraulic fluid can efficiently absorb heat from the exhaust gas.

  Furthermore, this heat pipe device is devised so that the working fluid flows smoothly through the heat exchange flow path and heat exchange can be performed efficiently.

  That is, in the evaporator, since it is necessary to ensure good scavenging performance of the exhaust gas, the flow area of the heat exchange flow path must be reduced. Accordingly, the hydraulic fluid is likely to receive strong flow resistance when passing through the heat exchange flow path. Moreover, the hydraulic fluid is vaporized by exchanging heat with the exhaust gas in the process of flowing through the heat exchange flow path.

  Thereby, bubbles are formed in the hydraulic fluid. Bubbles grow and gradually increase as they travel through the heat exchange flow path. If the bubbles grow large, the heat exchange channel may be blocked and the fluidity of the working fluid may be hindered. Since the amount of the liquid hydraulic fluid that contacts the inner wall surface of the heat exchange channel is also reduced, the heat exchange efficiency is also lowered.

  On the other hand, this heat pipe device is configured such that the amount of heat received by the hydraulic fluid flowing downstream of the heat exchange channel is smaller than the amount of heat received by the hydraulic fluid flowing upstream of the heat exchange channel. The heat received by the hydraulic fluid downstream of the heat exchange channel promotes bubble growth. In this heat pipe device, since the amount of heat decreases, it is possible to suppress the bubble from growing excessively large. Therefore, flow inhibition due to bubbles can be suppressed.

  The heat pipe device may also be configured such that the surface area of the inner wall surface of the heat exchange channel with which the hydraulic fluid can come into contact is smaller on the downstream side than on the upstream side of the heat exchange channel.

  Heat exchange between the working fluid and the exhaust gas is performed through the inner wall surface of the heat exchange channel. If the surface area is made smaller on the downstream side than on the upstream side of the heat exchange channel, the amount of heat received on the downstream side can be reduced with a simple structure.

  In that case, the heat exchange channel is partitioned into a plurality of branch channels by ribs extending in the direction in which the hydraulic fluid flows, and the width of the branch channel located on the downstream side of the heat exchange channel is It is good also as being formed larger than the width | variety of the said branch flow path located in the upstream of a heat exchange flow path.

  By doing so, the surface area of the inner wall surface of a heat exchange channel increases, and heat exchange is promoted. Moreover, since the working fluid is dispersed in each branch flow path and heat exchange is performed with the rectified state, heat exchange can be performed in a balanced manner.

  Moreover, the surface area of the inner wall surface of the heat exchange channel with which the hydraulic fluid can come into contact is smaller on the downstream side than on the upstream side of the heat exchange channel. Accordingly, since the amount of heat received by the hydraulic fluid is reduced on the downstream side, the growth of bubbles is suppressed, and flow inhibition due to bubbles can be suppressed.

  Furthermore, since the width on the downstream side is larger, even if bubbles grow larger, it is difficult to contact the rib. Therefore, the heat exchange flow path becomes difficult to block, and flow inhibition due to bubbles can be further suppressed.

  In that case, the ribs adjacent in the direction in which the hydraulic fluid flows may be alternately arranged.

  Then, when the bubbles that have grown greatly in the upstream branch flow channel flow into the downstream branch flow channel, the bubbles collide with the lower end of the downstream rib. Thereby, the bubbles are divided and flow into the downstream branch flow path in a small state. Accordingly, since the bubbles that have grown greatly on the upstream side are subdivided before reaching the downstream side, flow inhibition by the bubbles can be suppressed.

  The heat pipe device is also formed such that the width of the branch flow path positioned upstream in the direction in which the exhaust gas flows is larger than the width of the branch flow path positioned downstream in the direction in which the exhaust gas flows. It is good also as.

  If it does so, it will become easy to flow in into the branch flow path located in the upstream of a gas flow direction dynamically rather than the branch flow path located in the downstream of a gas flow direction. Since the temperature of the exhaust gas is higher on the upstream side in the gas flow direction than on the downstream side, an amount of hydraulic fluid corresponding to the exhaust gas temperature can be distributed to each branch flow path. Thereby, heat exchange can be made uniform throughout the gas flow direction.

  In addition, the width of each branch flow path changes in size depending on the ease of bubble growth. Therefore, flow inhibition due to bubbles can be suppressed.

  The heat pipe device may be configured such that the heat conductivity on the downstream side of the heat exchange channel is smaller than the heat conductivity on the upstream side of the heat exchange channel.

  If the thermal conductivity is small, the amount of heat received by the hydraulic fluid is small, so that bubble growth can be suppressed. In this case, since there is no structural restriction, it is excellent in convenience.

  The heat pipe device may be configured such that the evaporator is configured by a plurality of parts joined in contact with each other in a direction in which the hydraulic fluid flows.

  If it does so, it can manufacture easily also in the heat exchange flow path from which a structure and a property as mentioned above differ in a liquid flow direction.

  According to the disclosed technology, the heat of exhaust gas can be efficiently used for heating.

It is a figure for demonstrating the basic composition of a heat pipe device. It is the schematic which shows an example of the vehicle to which the technique to disclose is applied. It is the schematic which shows the structure of an air conditioner. It is a schematic perspective view which shows the principal part of an air conditioner. It is a schematic perspective view which shows the front lower side part of the partition which comprises the vehicle interior. It is a schematic perspective view of the part seen from the direction of arrow A in FIG. It is the schematic of the part seen from the direction of arrow B in FIG. It is the schematic which looked at the principal parts of vehicles, such as an exhaust pipe and a heat pipe device, from the upper part. It is a schematic perspective view which shows an exhaust heat recovery mechanism. It is a schematic sectional drawing of the waste heat recovery channel | path which shows the flow path through which exhaust gas flows. It is a schematic sectional drawing in the arrow CC line in FIG. It is a schematic perspective view which shows the cross section in the arrow DD line in FIG. It is a schematic sectional drawing of the waste heat recovery channel | path which shows a heat exchange flow path. It is a figure for demonstrating the influence of the bubble which generate | occur | produces in the hydraulic fluid which flows through a heat exchange flow path. (A) is a case where the flow path width is wide, and (b) is a case where the flow path width is narrow. It is the graph which illustrated the temperature change of the exhaust gas which flows through a heat exchange chamber. FIG. 14 is a view corresponding to FIG. 13 showing a modification of the heat exchange channel. FIG. 14 is a view corresponding to FIG. 13 showing a modification of the heat exchange channel. FIG. 14 is a view corresponding to FIG. 13 showing a modification of the heat exchange channel. FIG. 14 is a view corresponding to FIG. 13 showing a modification of the heat exchange channel. FIG. 14 is a view corresponding to FIG. 13 showing a modification of the heat exchange channel. FIG. 14 is a view corresponding to FIG. 13 showing a modification of the heat exchange channel.

  Hereinafter, embodiments of the disclosed technology will be described in detail based on the drawings. However, the following description is merely illustrative in nature and does not limit the present invention, its application, or its use.

  FIG. 2 illustrates an automobile 1 (vehicle) to which the disclosed technology is applied. The automobile 1 is equipped with an engine 2 (internal combustion engine) that uses gasoline as fuel. Power is generated by the combustion of gasoline, and the automobile 1 travels. A cabin 4 (vehicle compartment) in which a passenger enters is disposed at an intermediate portion of the body 3 of the automobile 1 in the front-rear direction (the front-rear direction with respect to the direction in which the automobile 1 goes straight, hereinafter the same). An engine room 5 (engine room) is disposed in front of the cabin 4.

  The engine room 5 is provided with an engine 2 that drives the front wheels. That is, in the present embodiment, a general front wheel drive (so-called FF system) automobile 1 is illustrated. A radiator 6 that cools cooling water (also simply referred to as cooling water) of the engine 2 and a condenser 8 that cools the refrigerant of the air conditioner 7 are disposed in front of the engine 2.

  The air conditioner 7 is disposed so as to face the interior of the cabin 4 from an intermediate portion in the vehicle width direction and the vehicle height direction on the front side of the cabin 4. The air conditioner 7 is also used as a defroster (DEF). Therefore, the air conditioner 7 is disposed immediately below the windshield 3 a that defines the upper front side of the cabin 4. The air conditioner 7 blows out temperature-adjusted air (cold air or hot air) from the air outlets arranged at various locations in the cabin 4 according to the operation of the passenger. Thereby, the cabin 4 can be cooled and heated.

  3 and 4 show the main structure of the air conditioner 7. An air conditioning duct 70 through which air flows is formed inside the air conditioner 7. One inlet 70a is provided at the upstream end of the air conditioning duct 70, and a plurality of (three in the illustrated example) outlets 70b including DEF are provided at the downstream end of the air conditioning duct 70 so as to be opened and closed. It has been. These outlets 70b communicate with the above-described outlet. Inside the air conditioning duct 70, an evaporator 71, a first heater core 72, a second heater core 73, and an air mixing chamber 74 are arranged in this order from the upstream side.

  A blower 75 for sending air to the air conditioner 7 is attached to the side of the air conditioner 7 (see also FIG. 5). The blower 75 is driven when the air conditioner 7 is operated, and sends outside air or air inside the cabin 4 to the air conditioner 7 through the introduction port 70a. The evaporator 71 is connected to the capacitor 8 via a refrigerant pipe 76 shown in FIG. As necessary, the refrigerant circulates between the evaporator 71 and the condenser 8 by the power of a compressor (not shown). When the refrigerant cooled by the condenser 8 absorbs heat by the evaporator 71, the air introduced into the air conditioner 7 is cooled and dried.

  The first heater core 72 is connected to the engine 2 and the radiator 6 via a cooling water pipe 77 shown in FIG. During operation of the engine 2, the coolant circulates through the radiator 6, the engine 2, and the first heater core 72 through the coolant pipe 77. At that time, since the temperature of the cooling water becomes high, the air passing through the first heater core 72 is heated by exchanging heat with the cooling water in the first heater core 72.

  The second heater core 73 constitutes a condenser of the heat pipe device 40 (the heat pipe device 40 will be described later). The second heater core 73 is disposed close to the downstream side of the first heater core 72 so that the air that has passed through the first heater core 72 passes therethrough. During operation of the engine 2, the air that has passed through the first heater core 72 is heated by the second heater core 73 as necessary.

  As shown in FIG. 3, a swingable air mixing door 78 is disposed in the vicinity of the first heater core 72. By swinging the air mixing door 78, a part or all of the air that has passed through the evaporator 71 flows on the upstream side of the first heater core 72, bypassing the first heater core 72 and the second heater core 73. Has been.

  During the operation of the air conditioner 7, the air bypassing the first heater core 72 and the second heater core 73 and the air passing through the first heater core 72 and the second heater core 73 are mixed in the air mixing chamber 74 and the temperature is adjusted. The air mixed in the air mixing chamber 74 is blown out into the cabin 4 through each outlet 70b and each outlet.

  As shown in FIG. 2, the exhaust gas generated in the engine 2 by the combustion of gasoline is discharged from the rear part of the automobile 1 through the exhaust pipe 9 connected to the engine 2. The exhaust pipe 9 passes through the lower side of the cabin 4, extends rearward from the engine room 5, and is disposed on the body 3 so that its end faces the rear of the automobile 1.

  FIG. 5 shows a front lower side portion of the partition wall 10 constituting the cabin 4 together with the air conditioner 7 and the exhaust pipe 9. The partition wall 10 is composed of a panel member or a reinforcing member provided integrally with the body 3, and includes a dash panel 10a (dash lower panel), a floor panel 10b, a cross member 10c, and the like.

  The dash panel 10a is installed so as to extend in the vehicle width direction and cover the lower side from an intermediate position in the vehicle height direction. Thereby, the dash panel 10 a is inside the body 3 and partitions the front lower part of the cabin 4 and the engine room 5. The air conditioner 7 is attached to the wall surface inside the dash panel 10a (the side with the cabin 4).

  The floor panel 10b is connected to the lower part of the dash panel 10a and extends substantially horizontally toward the rear. Thereby, the floor panel 10 b constitutes the lower part of the cabin 4. The dash panel 10a partitions the cabin 4 and the outside of the vehicle. The lower surface of the dash panel 10a faces the outside of the vehicle.

  A tunnel portion 11 (concave portion) extending in the front-rear direction is provided in the center portion of the floor panel 10b in the vehicle width direction. The tunnel portion 11 is recessed toward the cabin 4 side. As shown in FIG. 6, the front end portion of the tunnel portion 11 is continuous with the lower portion of the dash panel 10a. Thereby, the front end part of the tunnel part 11 is open | released by the engine room 5 ahead of the dash panel 10a.

  A cross member 10c is provided on the upper surface of the floor panel 10b so as to extend in the vehicle width direction across the tunnel portion 11 (see FIG. 5). The cross member 10c forms a closed cross-sectional structure and reinforces the rigidity of the body 3.

  As shown also in FIG. 7, the exhaust pipe 9 extends in the front-rear direction on the lower side of the cabin 4. The exhaust pipe 9 is accommodated in the tunnel portion 11. That is, most of the exhaust pipe 9 is located above the lowermost surface of the floor panel 10b. The front end portion of the exhaust pipe 9 is curved upward along the dash panel 10 a and is connected to the exhaust path of the engine 2.

  An exhaust treatment device is attached to an intermediate portion of the exhaust pipe 9 in the front-rear direction. Many exhaust treatment apparatuses include, for example, a three-way catalyst, a particle filter (PF), and the like, and have a function of removing harmful substances contained in exhaust gas such as NOx and soot.

  In the automobile 1, an underfoot catalyzer 12 including a three-way catalyst is disposed as an exhaust treatment device at an intermediate portion of an exhaust pipe 9 located on the lower side of the cabin 4. Although not shown, a direct catalyst including a three-way catalyst is also arranged at the upper end portion of the exhaust pipe 9 located in the vicinity of the engine 2. That is, as an exhaust treatment device including a three-way catalyst, the underfoot caterer 12 is located on the most downstream side of the exhaust pipe 9.

  A silencer 13 is disposed at the end portion of the exhaust pipe 9 (see FIG. 2). An exhaust heat recovery mechanism 20 is provided in a portion of the exhaust pipe 9 on the downstream side of the underfoot caterer 12 and on the upstream side of the silencer 13.

<Exhaust heat recovery mechanism 20>
As shown in FIGS. 8 and 9, the exhaust heat recovery mechanism 20 includes an exhaust heat recovery passage 21 and a bypass passage 22 that branch the exhaust pipe 9 into two branches, and a switching valve 23. The switching valve 23 is installed at a branch portion located upstream of the exhaust heat recovery passage 21 and the bypass passage 22. The exhaust heat recovery passage 21 and the bypass passage 22 are accommodated in the tunnel portion 11 in a state of being aligned in the vehicle width direction.

  The switching valve 23 switches the path through which the exhaust gas flows to either the exhaust heat recovery passage 21 or the bypass passage 22. That is, the switching valve 23 switches between a heat recovery position where the exhaust gas flows through the exhaust heat recovery passage 21 and a heat non-recovery position where the exhaust gas flows through the bypass passage 22. The switching valve 23 when not energized is configured to be in a heat non-recovery position. A heat recovery unit 25 is provided in the exhaust heat recovery passage 21.

  FIG. 10 shows the exhaust heat recovery passage 21 (schematic cross-sectional view). An arrow Y1 in FIG. 10 indicates the direction in which the exhaust gas flows in the heat recovery unit 25 (also referred to as the gas flow direction). The exhaust heat recovery passage 21 has an upstream side throttle part 24, a heat recovery part 25, and a downstream side throttle part 26.

  The upstream throttle unit 24 and the downstream throttle unit 26 are provided in a pipe constituting the exhaust heat recovery passage 21. The upstream throttle unit 24 is located upstream of the heat recovery unit 25 in the gas flow direction, and the downstream throttle unit 26 is positioned downstream of the heat recovery unit 25 in the gas flow direction.

  The upstream side throttle part 24 and the downstream side throttle part 26 are formed so that the cross section of the flow path is gradually reduced, and relieve the flow velocity and disturbance of the exhaust gas flowing through the heat recovery part 25. Therefore, heat exchange in the heat recovery unit 25 is stabilized by the upstream throttle unit 24 and the downstream throttle unit 26.

  The heat recovery section 25 has a substantially rectangular channel cross section. The heat recovery unit 25 constitutes an evaporator of the heat pipe device 40.

<Heat recovery unit 25>
As shown in FIGS. 11 and 12, the heat recovery unit 25 is configured by assembling a rectangular parallelepiped member (heat recovery device 30) between the pipes of the exhaust heat recovery passage 21. The heat recovery unit 30 is formed using a material (for example, stainless steel) excellent in corrosion resistance, thermal conductivity, and the like. Such a material is used for each part constituting the heat recovery device 30 such as a pipe support wall 31, a gas pipe 34, and a rib 51 described later, and the heat recovery device 30 is integrally formed.

  The heat recovery unit 30 includes a rectangular cylindrical main body 30a extending in the front-rear direction, a lower bulge 30b bulging downward from the lower surface of the main body 30a, and an upper bulge bulging upward from the upper surface of the main body 30a. And a protruding portion 30c.

  The front surface and the rear surface of the main body 30a are partitioned by a pair of pipe support walls 30d and 30d. Each pipe support wall 30d is arranged to face the gas flow direction. The outer periphery of each pipe support wall 30d is fixed to the inner surface of the main body 30a without a gap. Thereby, the periphery of each pipe support wall 30d is sealed.

  Thereby, a sealed heat exchange chamber 31 is provided inside the main body 30a. An air chamber 32 is provided inside the upper bulging portion 30c, and a liquid chamber 33 is provided inside the lower bulging portion 30b. The upper surface of the heat exchange chamber 31 faces the air chamber 32, and the lower surface of the heat exchange chamber 31 faces the liquid chamber 33.

  A plurality of gas pipes 34 are installed in the heat exchange chamber 31. Each gas pipe 34 is a hollow thin plate-like pipe. The inside of the gas pipe 34 is partitioned by a plurality of fins 34a and subdivided. Both ends of each gas pipe 34 are integrally attached to the two pipe support walls 30d and 30d.

  As shown in FIG. 10, each gas pipe 34 penetrates each pipe support wall 30d. Each of the gas pipes 34 is disposed between the pipe support walls 30d so as to extend in the vertical direction and the front-rear direction so as to be parallel to each other with a slight gap therebetween. Thus, the exhaust gas flowing into the exhaust heat recovery passage 21 flows from the front to the rear through the gas pipes 34 and passes through the heat exchange chamber 31.

  As shown in FIGS. 12 and 13, a plurality of heat exchange passages 50 extending in parallel to each other are formed between the adjacent gas pipes 34 of the heat exchange chamber 31 so as to intersect the flow of the exhaust gas. Yes. The lower end portion of each heat exchange channel 50 is open to the liquid chamber 33 over the entire front-rear direction. The upper end portion of each heat exchange channel 50 is also opened to the air chamber 32 over the entire area in the front-rear direction. Accordingly, each heat exchange channel 50 communicates with the liquid chamber 33 and the air chamber 32 over the entire region in the gas flow direction (the heat exchange channel 50 will be described later separately).

  The air chamber 32 is formed in a substantially rectangular parallelepiped shape, and a liquid outlet 36 is provided on the front surface thereof. The liquid outlet 36 is disposed at a portion of the air chamber 32 that is biased toward one end in the left-right width direction.

  The lower portion of the liquid chamber 33 is formed so as to incline upward from the front toward the rear and approach the heat exchange chamber 31. Thereby, the volume of the liquid chamber 33 gradually decreases from the upstream side to the downstream side in the gas flow direction. A liquid inlet 38 is provided on the side surface of the liquid chamber 33 on the other end side in the left-right width direction. The liquid inflow port 38 is arranged at a rear part.

<Heat pipe device 40>
The automobile 1 is provided with a heat pipe device 40 so that the heat of the exhaust gas can be efficiently used for heating the cabin 4. The heat pipe device 40 is a heat transfer cycle using a heat pipe technology. The heat pipe device 40 includes a second heater core 73 and a heat recovery unit 25, and a circulation pipe 41 connected to the second heater core 73 and the heat recovery unit 25.

  The interiors of the second heater core 73, the heat recovery unit 25, and the circulation pipe 41 are in communication. Thereby, in these, the space (heat transfer space) which was connected and sealed mutually was formed. In the heat recovery unit 25, a heat transfer space is formed by the liquid chamber 33, the heat exchange flow path 50, and the air chamber 32.

  The inside of the heat transfer space is highly decompressed. An appropriate amount of hydraulic fluid (aqueous solution, alcohol, refrigerant, etc.) is sealed inside the heat transfer space. Accordingly, as shown in FIGS. 10 and 11, the working fluid is stored in a part of the second pipe 41 b, the liquid chamber 33, and a part of the heat exchange flow path 50. The amount of the working fluid is an example.

  The circulation pipe 41 has a first pipe 41a and a second pipe 41b. The first pipe 41 a is connected to the liquid outlet 36. The second pipe 41 b is connected to the liquid inlet 38. The hydraulic fluid vaporized by the heat recovery unit 25 is sent to the second heater core 73 through the first pipe 41a. The hydraulic fluid liquefied by the second heater core 73 is sent to the heat recovery unit 25 through the second pipe 41b.

  Since the 2nd heater core 73 is extended in the narrow inside of the air conditioner 7, the capacity | capacitance is designed small. Since the heat recovery part 25 is also provided in the exhaust heat recovery passage 21 accommodated in the tunnel part 11 in a branched state, its capacity is designed to be small. Since the heat capacity increases as the amount of hydraulic fluid increases, the circulation pipe 41 is also composed of a thin tube (for example, the inner diameter is 2 mm or more and 20 mm or less) so that the capacity is reduced. That is, the heat pipe device 40 is configured to be compact.

  As shown in FIG. 6, the opening 14 is formed in the site | part adjacent to the upper part of the tunnel part 11 in the dash panel 10a. As shown in FIGS. 4, 7, and 8, a pipe connection portion 79 is installed inside the dash panel 10 a. The pipe connection part 79 faces the engine room 5 in front through the opening 14. The pipe connection unit 79 relays pipes (refrigerant pipe 76, cooling water pipe 77, circulation pipe 41) connected to the evaporator 71, the first heater core 72, and the second heater core 73 housed in the air conditioner 7.

  A joint 79 a connected to the second heater core 73 is installed on the front surface of the pipe connection portion 79 facing the engine room 5. A circulation pipe 41 extending from the heat recovery unit 25 is connected to these joints 79a. The main body of the circulation pipe 41 of this embodiment is composed of a metal pipe 42 (hard pipe) and a rubber pipe 43 (soft pipe).

  The metal tube 42 is connected to the heat recovery unit 25 and extends downward from the heat recovery unit 25 to the lower side of the floor panel 10b. The metal pipe 42 is accommodated in the tunnel portion 11 along the exhaust pipe 9. In particular, the metal pipe 42 of the first pipe 41a is arranged so as to extend along the upper part of the exhaust pipe 9 (see FIG. 7). That is, the metal pipe 42 of the first pipe 41 a is disposed deeper in the tunnel portion 11 than the exhaust pipe 9.

  The metal pipe 42 of the second pipe 41 b is arranged so as to extend along the side part of the exhaust pipe 9. The front end portions of these metal tubes 42 are located at the front end portion of the floor panel 10b.

  One end of the rubber tube 43 is connected to the front end portion of the metal tube 42. The rubber tube 43 extends along the dash panel 10a in a bent state. The other end of the rubber tube 43 is connected to the joint 79a. The circulation pipe 41 is not supported by the dash panel 10a or the floor panel 10b, but is supported by the exhaust pipe 9 and the joint 79a (the pipe connection portion 79 and further the air conditioner 7).

<Operation of Exhaust Heat Recovery Mechanism 20 and Heat Pipe Device 40>
In the normal state, the switching valve 23 is located at the heat non-recovery position. Therefore, the exhaust gas generated during the operation of the engine 2 flows through the bypass passage 22 and is exhausted as in the conventional case. Therefore, the heat pipe device 40 does not operate.

  On the other hand, when a passenger requests heating by operating the air conditioner 7 while the engine 2 is operating, the switching valve 23 is switched to the heat recovery position. Thereby, the exhaust gas flows into the exhaust heat recovery passage 21. The exhaust gas introduced into the exhaust heat recovery passage 21 flows into the gas pipe 34 after the flow velocity and turbulence are alleviated by the upstream throttle 24.

  In the process in which the exhaust gas passes through the gas pipe 34, the working fluid that accumulates in each heat exchange channel 50 absorbs the heat of the exhaust gas and vaporizes, and the working fluid vapor is generated. The steam of the working fluid moves to the second heater core 73 through the first pipe 41a. The vapor of the working fluid that has moved to the second heater core 73 dissipates heat to the air introduced into the air conditioner 7 and liquefies. The hydraulic fluid liquefied by the second heater core 73 moves to the heat recovery unit 25 due to the vapor pressure of the hydraulic fluid and the action of gravity.

  That is, the hydraulic fluid exchanges between the second heater core 73 and the heat recovery unit 25 through the circulation pipe 41 while changing the phase by heat exchange with the exhaust gas and heat exchange with the air introduced into the air conditioner 7. Circulate between them. Thereby, the cabin 4 can be heated by directly using the heat of the exhaust gas.

  In the automobile 1, an underfoot caterer 12 is installed in the exhaust pipe 9. The three-way catalyst included in the underfoot caterer 12 needs a temperature higher than a predetermined temperature in order to function properly. Therefore, if the heat recovery unit 25 is disposed on the upstream side of the underfoot caterer 12, the function of the underfoot caterer 12 may be impaired.

  On the other hand, in the automobile 1, the heat recovery unit 25 is disposed on the downstream side of the underfoot caterer 12. Therefore, even if exhaust heat is used in the heat pipe device 40, the function of the underfoot caterer 12 can be maintained.

  On the other hand, when a device that is affected by the use of exhaust heat, such as the underfoot cater 12, is installed in the exhaust pipe 9, if the heat recovery unit 25 is disposed on the downstream side of the device, the circulation pipe 41 becomes long. When the circulation pipe 41 becomes long, there is a possibility that the heat transport efficiency is lowered and the durability of the circulation pipe 41 is lowered.

  That is, since the vapor of the working fluid flowing through the first pipe 41a is radiated and easily liquefied, the heat transport efficiency is lowered. On the other hand, in the automobile 1, the first pipe 41 a is arranged so as to extend along the exhaust pipe 9. Thereby, the 1st piping 41a receives the radiant heat which the exhaust pipe 9 discharge | releases, and heat dissipation is suppressed. Therefore, even if the circulation piping 41 becomes long, the fall of heat transport efficiency can be reduced.

  Further, the first pipe 41 a is disposed deeper in the tunnel portion 11 than the exhaust pipe 9. Therefore, heat radiation is suppressed by the heat generated by the exhaust pipe 9, and a decrease in heat transport efficiency can be further reduced. Further, since the portion extending along the exhaust pipe 9 is formed by the metal pipe 42, heat is easily transmitted to the circulation pipe 41. Accordingly, it is possible to further reduce the decrease in heat transport efficiency.

  By arranging the circulation pipe 41 extending along the lower side of the floor panel 10 b along the exhaust pipe 9, it is possible to suppress foreign matters such as stones that are leap up during traveling from colliding with the circulation pipe 41. Therefore, even if the circulation piping 41 becomes long, the fall of durability of the circulation piping 41 can be reduced. Since the circulation pipe 41 is accommodated in the tunnel portion 11, the deterioration of the durability of the circulation pipe 41 can be further reduced.

  Furthermore, if the heat recovery unit 25 is disposed on the downstream side of a device that uses exhaust heat, such as the underfoot cater 12, the temperature of the exhaust gas that passes through the heat recovery unit 25 may decrease. Therefore, there is a possibility that the heat that can be recovered by the heat recovery unit 25 is insufficient.

  In this automobile 1, the heat exchange flow path 50 is devised so that the hydraulic fluid circulates smoothly and efficiently exchanges heat with the exhaust gas in response to a decrease in heat transport efficiency and a decrease in exhaust heat recovery efficiency.

<Heat exchange flow path 50>
As described above, when the exhaust gas is continuously introduced into the exhaust heat recovery passage 21, the liquefied hydraulic fluid continuously flows into the liquid chamber 33 through the liquid inlet 38. Then, the hydraulic fluid flows into the heat exchange channels 50 from below and flows upward. The arrow Y2 in FIGS. 10 and 13 indicates the direction in which the hydraulic fluid flows in the heat recovery unit 25 (also referred to as the liquid flow direction).

  The hydraulic fluid exchanges heat with the exhaust gas flowing through each gas pipe 34 in the process of passing through each heat exchange channel 50. The heat exchange is performed through the wall material of the gas pipe 34 excellent in heat conductivity (which constitutes the wall surface of the heat exchange channel 50), and the hydraulic fluid receives heat from the inner wall surface of the heat exchange channel 50. As a result, the hydraulic fluid is vaporized and vapor of the hydraulic fluid is generated. The generated vapor of hydraulic fluid flows into the air chamber 32 and flows out of the air chamber 32 through the liquid outlet 36.

  As shown in FIGS. 12 and 13, the heat exchange channel 50 of this embodiment is provided with a plurality of ribs 51 extending in the liquid flow direction, and the heat exchange channel 50 includes a plurality of branch channels 52. It is divided into. Thereby, the surface area of the inner wall surface of the heat exchange channel 50 is increased, and heat exchange is promoted. In addition, since the working fluid is dispersed in each branch passage 52 and heat exchange is performed with the exhaust gas in a rectified state, heat exchange can be performed in a balanced manner.

  Since the flow of hydraulic fluid is made uniform, the liquid flow direction is not limited to the vertical direction. Since stable heat exchange can be performed in any direction such as a horizontal direction or an oblique direction, there is an advantage that the direction in which the heat recovery device 30 is installed is not restricted.

  However, when the heat exchange flow path 50 is divided into a plurality of sections, the flow path width becomes narrower. Thereby, the fluidity | liquidity of a hydraulic fluid is inhibited and there exists a possibility of causing the fall of heat exchange efficiency and heat transport efficiency. This point will be specifically described.

  The thickness t (size in the left-right direction) of the heat exchange channel 50 must be small in order to ensure the scavenging performance of the exhaust gas (see FIG. 12). In addition to this, when the width W (size in the front-rear direction) of the heat exchange channel 50 becomes narrower, the flow resistance of the hydraulic fluid increases.

  Further, the hydraulic fluid is vaporized in the process of passing through each heat exchange channel 50. Thereby, as shown in FIG. 14, bubbles B are formed in the hydraulic fluid. The bubbles B grow as they progress through the heat exchange flow path 50 and gradually increase.

  As shown in FIG. 14A, even if the bubble B grows, the bubble B hardly contacts the rib 51 if the width W of the heat exchange channel 50 is larger than the lateral width of the bubble B. The heat exchange channel 50 can be passed through. Therefore, in this case, since the heat exchange flow path 50 is not blocked, the presence of the rib 51 does not affect the fluidity of the hydraulic fluid.

  On the other hand, as shown in FIG. 14B, when the width W of the heat exchange channel 50 is smaller than the lateral width of the bubble B, the bubble B comes into contact with the rib 51 and receives a resistance while receiving the resistance. Pass through road 50. Therefore, since the heat exchange flow path 50 is blocked, the fluidity of the working fluid is hindered. Since the amount of the liquid working fluid that contacts the rib 51 is also reduced, the heat exchange efficiency is also reduced.

  In view of this, the heat exchange channel 50 is further devised so that heat exchange can be efficiently performed in a state where the working fluid smoothly flows through the heat exchange channel 50.

  First, when compared at the same position in the liquid flow direction, the width W of the branch flow path 52 located upstream in the gas flow direction is greater than the width W of the branch flow path 52 located downstream in the gas flow direction. Is also formed large. Specifically, the width W of the branch flow path 52 is gradually increased from the downstream side in the gas flow direction toward the upstream side.

  As a result, the hydraulic fluid is more likely to dynamically flow into the branch flow path 52 located upstream in the gas flow direction than the branch flow path 52 located downstream in the gas flow direction. Since the temperature of the exhaust gas is higher on the upstream side in the gas flow direction than on the downstream side, an amount of hydraulic fluid corresponding to the exhaust gas temperature can be distributed to each branch passage 52. Thereby, heat exchange can be made uniform throughout the gas flow direction.

  The width W of each branch flow path 52 changes in a magnitude relationship corresponding to the degree of growth of the bubbles B. Therefore, the flow inhibition by the bubbles B can also be suppressed.

  The width W of each branch channel 52 can be appropriately set according to the specification. However, as shown in FIG. 15, the temperature of the exhaust gas flowing through the heat exchange chamber 31 shows a curve that gradually decreases from the upstream side toward the downstream side at a predetermined rate of change. Therefore, the width W of each branch passage 52 is preferably formed so as to change in accordance with the change in the temperature curve of the exhaust gas (the width W increases as the temperature of the exhaust gas increases).

  Secondly, the amount of heat received by the hydraulic fluid flowing on the downstream side of the heat exchange channel 50 is configured to be smaller than the amount of heat received by the hydraulic fluid flowing on the upstream side of the heat exchange channel 50. If the amount of heat received by the hydraulic fluid flowing on the downstream side of the heat exchange channel 50 is relatively reduced, the bubble B can be prevented from growing greatly. Therefore, flow inhibition due to the bubbles B can be suppressed.

  In this embodiment, the heat exchange channel 50 is divided into an upstream side and a downstream side. The upstream heat exchange channel 50 is partitioned into a plurality of branch channels 52 (upstream branch channels 52a) by a group of ribs 51 (upstream ribs 51a). The downstream heat exchange channel 50 is partitioned into a plurality of branch channels 52 (downstream branch channels 52b) by a group of ribs 51 (downstream ribs 51b).

  The upstream rib 51 a extends from the lower end (upstream end) of the heat exchange channel 50 to an intermediate portion of the heat exchange channel 50. The downstream rib 51b extends from an intermediate portion of the heat exchange channel 50 to the upper end (downstream end) of the heat exchange channel 50.

  When compared at the same position in the gas flow direction, the downstream branch flow path 52b is formed to have a larger width (equal or greater) than the upstream branch flow path 52a. Thereby, the surface area of the inner wall surface of the heat exchange channel 50 with which the hydraulic fluid can come into contact is formed smaller on the downstream side than on the upstream side of the heat exchange channel 50.

  If the surface area of the inner wall surface of the heat exchange channel 50 with which the hydraulic fluid can come into contact is small, the amount of heat received by the hydraulic fluid is reduced accordingly. Therefore, in the downstream branch flow path 52b, the growth of the bubbles B is suppressed, so that the flow inhibition by the bubbles B can be suppressed.

  Since the downstream branch flow path 52b has a larger width W, even if the bubble B grows, the bubble B is unlikely to contact the downstream rib 51b. Accordingly, the contact resistance of the bubbles B is reduced, and the flow inhibition by the bubbles B can be further suppressed.

  Third, the upstream ribs 51a and the downstream ribs 51b adjacent to each other in the liquid flow direction are alternately arranged. The lower end 53 of the downstream rib 51b is located in the middle of two adjacent upstream ribs 51a.

  As described above, when the rib 51 is arranged, if the bubble B grows large in the upstream branch flow path 52a, the bubble B flows into the downstream branch flow path 52b, and then the lower end 53 of the downstream rib 51b. Collide with. Thereby, the bubble B is divided and flows into the downstream branch flow path 52b in a small state. Since the bubbles B that have grown greatly in the middle of the heat exchange channel 50 are subdivided, the flow inhibition by the bubbles B can be suppressed.

  Fourth, the downstream side of the heat exchange channel 50 (in this embodiment, the portion where the downstream branch channel 52b is formed) is the upstream side of the heat exchange channel 50 (in this embodiment, the upstream side branch). The heat conductivity is smaller than that of the portion where the flow path 52a is formed.

  For example, if materials having different thermal conductivities are used as the materials constituting the gas pipe 34 and the rib 51 on the downstream side and the upstream side of the heat exchange flow path 50, this configuration can be achieved. Instead of using materials having different thermal conductivities, films having different thermal conductivities may be formed on the gas pipes 34 and the ribs 51 having the same thermal conductivity.

  When the thermal conductivity is small, the amount of heat received by the hydraulic fluid is small. Therefore, the growth of the bubbles B can be further suppressed.

  When forming such a heat exchange flow path 50, it is preferable to comprise the heat recovery device 30 with a plurality of (in this case, two) parts. That is, the heat recovery device 30 is divided into two parts in the liquid flow direction, and includes an upstream part 30U in which the upstream branch flow path 52a is formed and a downstream part 30D in which the downstream branch flow path 52b is formed. The heat recovery unit 30 is formed by abutting, joining, and integrating the upstream part 30U and the downstream part 30D.

  If it does so, it can manufacture easily also with the heat exchange flow path 50 from which a structure and a property as mentioned above differ in a liquid flow direction.

<Modification of Heat Exchange Channel 50>
The form of the heat exchange channel 50 is not limited to the above-described embodiment. 16A to 16F show modifications 50A to 50F of the heat exchange flow path 50. FIG. In addition, except the form of the heat exchange flow path 50, it is the same as embodiment mentioned above. In the following description, different points of the heat exchange channel 50 will be mainly described.

  FIG. 16A shows a first modification. As in the heat exchange flow path 50 of the embodiment, the heat exchange flow path 50A of this modification is divided into two, and the upstream heat exchange flow path 50 includes a plurality of upstream ribs 51a. A downstream heat exchange channel 50 is partitioned into a plurality of downstream branch channels 52b by downstream ribs 51b.

  In the heat exchange flow path 50A of this modification, the width W of the upstream branch flow path 52a and the downstream branch flow path 52b is formed to be the same. And the width W of the downstream branch flow path 52b is formed larger than the width W of the upstream branch flow path 52a.

  Since the downstream branch flow path 52b has a smaller surface area on the inner wall surface, the amount of heat received by the hydraulic fluid is reduced in the downstream branch flow path 52b, and the growth of the bubbles B is suppressed. Moreover, since the downstream branch flow path 52b has less contact resistance of the bubble B, flow inhibition can be suppressed. Since the upstream ribs 51 a and the downstream ribs 51 b are alternately arranged, the bubbles B can be subdivided in the middle of the heat exchange flow path 50.

  FIG. 16B shows a second modification. Unlike the heat exchange flow path 50A of the first modification, the heat exchange flow path 50B of this modification is arranged so as to be continuous with the upstream rib 51a (not arranged alternately). ). Except for the point that the bubbles B can be subdivided in the middle of the heat exchange flow path 50, the same effect as the first modification can be obtained.

  In this modified example, since the lower end 53 of the downstream rib 51b is not located between the two adjacent upstream ribs 51a, the bubble B and the operation are moved from the upstream branch flow path 52a to the downstream branch flow path 52b. There is an advantage that the liquid flows smoothly.

  FIG. 16C shows a third modification. The heat exchange flow path 50C of this modification is formed such that the ribs 51 become gradually longer from the upstream side to the downstream side in the gas flow direction. The upstream end of each rib 51 is located at the upstream end of the heat exchange flow path 50. As a result, a space is formed on the downstream side of each branch flow path 52 so as to expand larger toward the upstream side in the gas flow direction.

  Therefore, on the upstream side in the gas flow direction in which the bubbles B are likely to grow, the growth of the bubbles B is suppressed, and the grown bubbles B are difficult to contact the ribs 51.

  FIG. 16D shows a fourth modification. The heat exchange channel 50D of this modification corresponds to a modification of the heat exchange channel 50C of the third modification. In this modification, the downstream rib 51b is omitted from the heat exchange flow path 50 of the embodiment so that the upstream rib 51 in the gas flow direction is substantially uniformly shortened. As a result, a space is formed that greatly expands downstream of the branch flow path 52 located on the upstream side in the gas flow direction.

  Therefore, on the upstream side in the gas flow direction in which the bubbles B are likely to grow, the growth of the bubbles B is suppressed, and the grown bubbles B are difficult to contact the ribs 51. The ribs 51 may be continuous in the liquid flow direction as in the third modified example, and the group of ribs 51 having different lengths in the gas flow direction is not limited to two but may be three or more. May be.

  FIG. 16E shows a fifth modification. In the heat exchange flow path 50E of this modification, the heat exchange flow path 50 is divided into an upstream, a middle flow, and a downstream. In each channel, a plurality of ribs 51 are arranged at equal intervals or at different intervals (the latter in the figure), and a plurality of branch channels 52 are formed. The width W of each of the upstream, middle stream, and downstream branch flow paths 52 is different, and increases toward the downstream side. The ribs 51 adjacent to each other in the liquid flow direction are arranged alternately.

  Therefore, since the amount of heat received by the hydraulic fluid is smaller toward the downstream side, the growth of the bubbles B is suppressed. Moreover, since the contact resistance of the bubble B is smaller toward the downstream side, the flow inhibition can be suppressed. Since the ribs 51 adjacent to each other in the liquid flow direction are alternately arranged at two locations of the heat exchange channel 50, the bubbles B can be further subdivided. In the case of this modification, it is preferable that the heat recovery unit 30 is composed of three parts. The heat exchange channel 50 may be divided into four or more in the liquid flow direction.

  FIG. 16F shows a sixth modification. A large number of short ribs 51 are installed in the heat exchange flow path 50F of this modification. Each rib 51 is arranged such that the distance between the two ribs 51 and 51 adjacent to each other in the gas flow direction increases toward the downstream side in the liquid flow direction. The ribs 51 adjacent in the liquid flow direction are arranged alternately.

  Therefore, in the heat exchange flow path 50 of this modification, the branch flow path 52 is further subdivided, and the working fluid passes through the heat exchange flow path 50 through various paths. Since the amount of heat received by the hydraulic fluid is smaller toward the downstream side, the growth of the bubbles B is suppressed. Moreover, since the contact resistance of the bubble B is smaller toward the downstream side, the flow inhibition can be suppressed. Since the ribs 51 adjacent in the liquid flow direction are alternately arranged at a plurality of locations in the liquid flow direction of the heat exchange channel 50, the bubbles B can be further subdivided.

  In the illustrated example, the ribs 51 are arranged in a line in the gas flow direction, but the arrangement of the ribs 51 may be random. The length of the rib 51 may also be changed in the gas flow direction or the liquid flow direction. In short, it is only necessary to realize the suppression of the growth of the bubbles B and / or the suppression of the flow inhibition by the bubbles B.

  The disclosed technology is not limited to the above-described embodiment, and includes other various configurations.

  For example, a vehicle to which the disclosed technology can be applied is not limited to a vehicle driven by a gasoline engine. The disclosed technology can also be applied to a vehicle equipped with a diesel engine or an electric vehicle using a combination of an engine and a motor. In short, any vehicle that exhausts exhaust gas during driving may be used.

  The drive system of the vehicle is not limited to FF, and may be FR, RR, or MR. That is, the arrangement of the engine is not limited to the front part of the vehicle. The exhaust pipe may be provided with an exhaust treatment device such as a NOx absorption reduction catalyst (NSC), a urea selective reduction catalyst (SCR), and an external EGR that recirculates the exhaust gas.

  In the embodiment, in order to obtain smooth fluidity of the hydraulic fluid and good heat exchange efficiency, the heat recovery device 30 provided with a plurality of devices has been exemplified. However, it is not essential to combine all of these devices. Appropriate devices can be selected and used according to the specifications. The same applies to the form of each modification.

1 Automobile (vehicle)
2 Engine (Internal combustion engine)
4 cabin (cabin)
7 Air Conditioner 9 Exhaust Pipe 12 Underfoot Cater 20 Waste Heat Recovery Mechanism 21 Waste Heat Recovery Passage 22 Bypass Passage 23 Switching Valve 25 Heat Recovery Unit (Evaporator)
30 heat recovery device 31 heat exchange chamber 32 air chamber 33 liquid chamber 34 gas pipe 36 liquid outlet 38 liquid inlet 40 heat pipe device 41 circulation pipe 50 heat exchange passage 51 rib 52 branch passage 73 second heater core (condenser)

Claims (7)

A heat pipe device installed in a vehicle and capable of heating a passenger compartment,
The vehicle is
An internal combustion engine for generating power of the vehicle;
An exhaust pipe for discharging exhaust gas generated in the internal combustion engine;
An air conditioner that is arranged facing the interior of the passenger compartment and blows out air into the passenger compartment.
With
The heat pipe device is
A condenser installed in the air conditioner;
An evaporator installed in the exhaust pipe;
A circulation pipe connected to the condenser and the evaporator to circulate the working fluid;
With
The evaporator has a heat exchange flow path arranged to intersect the flow of exhaust gas,
The hydraulic fluid flowing through the heat exchange channel is vaporized by exchanging heat with exhaust gas,
The heat pipe device is configured such that the amount of heat received by the hydraulic fluid flowing downstream of the heat exchange channel is smaller than the amount of heat received by the hydraulic fluid flowing upstream of the heat exchange channel. In the heat pipe device according to claim 1,
The heat pipe device, wherein a surface area of an inner wall surface of the heat exchange channel with which the hydraulic fluid can contact is formed smaller on the downstream side than on the upstream side of the heat exchange channel. In the heat pipe device according to claim 2,
The heat exchange flow path is partitioned into a plurality of branch flow paths by ribs extending in a direction in which the hydraulic fluid flows,
The heat pipe device, wherein a width of the branch flow channel located on the downstream side of the heat exchange flow channel is formed larger than a width of the branch flow channel located on the upstream side of the heat exchange flow channel. In the heat pipe device according to claim 3,
A heat pipe device in which the ribs adjacent to each other in a direction in which the hydraulic fluid flows are alternately arranged. In the heat pipe device according to claim 3 or 4,
The heat pipe device, wherein a width of the branch flow path located upstream in the direction in which the exhaust gas flows is formed larger than a width of the branch flow path located downstream in the direction in which the exhaust gas flows. In the heat pipe device according to any one of claims 1 to 5,
The heat pipe device, wherein the heat conductivity on the downstream side of the heat exchange channel is smaller than the heat conductivity on the upstream side of the heat exchange channel. In the heat pipe device according to any one of claims 1 to 6,
The heat pipe device, wherein the evaporator is composed of a plurality of parts joined in contact with each other in a direction in which the hydraulic fluid flows.

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