JP6304328B2 - Engine exhaust heat recovery device - Google Patents

Description

  The present invention relates to an engine exhaust heat recovery apparatus that recovers heat of exhaust gas exhausted from an engine by a heat pipe and heat transports the catalyst for early activation of the catalyst and promotion of warming up of the engine, for example.

In automobiles, a catalyst is placed on the exhaust passage as a purification device that purifies harmful substances such as nitrogen oxides (NOx), carbon monoxide (CO), and hydrocarbons (HC) contained in the exhaust gas discharged from the engine. It is attached to.
This catalyst is activated by increasing its temperature to improve the purification efficiency, but has a feature that the purification efficiency decreases when the temperature becomes too high. In view of this, various techniques have been proposed in which the catalyst is activated early after the engine is started to improve the purification efficiency, and the temperature of the catalyst is prevented from being increased.

  For example, Patent Document 1 describes an exhaust heat recovery apparatus in which a first loop heat pipe using pure water as a heat exchange medium is disposed between an exhaust passage downstream of the catalyst and the catalyst. In the exhaust heat recovery apparatus of Patent Document 1, the heat of the exhaust gas recovered in the exhaust passage by the first loop heat pipe is radiated into the catalyst to activate the catalyst early.

  Further, in the exhaust heat recovery apparatus of Patent Document 1, a second loop heat pipe using pure water as a heat exchange medium is disposed between the catalyst and the second heat radiating part in which the heater flow path is provided. Yes. And the exhaust-heat recovery apparatus of patent document 1 is suppressing the high temperature of a catalyst by dissipating the heat which the 2nd loop type heat pipe collect | recovered within the catalyst through a 2nd thermal radiation part.

  By the way, in recent years, in the engine speed range where the engine load is low, the thermal efficiency of the engine is improved by suppressing the fuel injection amount by making the air-fuel ratio leaner or increasing the compression ratio. At this time, the exhaust temperature, which is the temperature of the exhaust gas, is about 150 ° C., for example.

  On the other hand, in the engine speed range where the engine load is high, the fuel injection amount relatively easily increases with the rich air-fuel ratio, so the exhaust gas temperature, which is the temperature of the exhaust gas, rises to about 800 ° C., for example. For this reason, it is desired that the heat pipe that thermally transports the heat of the exhaust gas be compatible with a wide exhaust temperature range from a low temperature range to a high temperature range.

  However, the temperature range in which the heat pipe can transport heat, that is, the operating temperature range, is determined by the type of the fluid medium sealed inside. For this reason, multiple heat pipes are required to support a wide range of exhaust temperatures, but the number of heat pipes is smaller in terms of limited exhaust passage space and increased exhaust resistance. Is preferred.

  Further, for example, in the case of a heat pipe using pure water as a fluid medium, the operating temperature range is 30 ° C. to 250 ° C., and in the case of a heat pipe using sodium as a fluid medium, the operating temperature range is 600 ° C. to 1200 ° C. Become.

  For this reason, when heat of exhaust gas is transported by heat between a low-temperature heat pipe sealed with pure water and a high-temperature heat pipe sealed with sodium, the heat of the exhaust gas in the temperature range of 250 ° C. to 600 ° C. There was a problem that neither the low temperature heat pipe nor the high temperature heat pipe could be recovered.

JP 2010-059960 A

  In view of the above problems, an object of the present invention is to provide an engine exhaust heat recovery device that can suppress an increase in the number of heat pipes and can cope with a wide exhaust temperature range.

  The present invention relates to an exhaust heat recovery apparatus for an engine that transports heat of exhaust gas discharged from a combustion chamber of the engine through a heat pipe in which a fluid medium is sealed, and the exhaust passage through which the exhaust gas flows down Two heat pipes, a part of which is installed inside, a condensing means for condensing the fluid medium in a gas phase, a temperature detecting means for detecting an exhaust temperature which is the temperature of the exhaust gas, and vaporization of the fluid medium A low-temperature heat pipe in which a low-temperature fluid medium corresponding to the exhaust temperature in a low-temperature region is sealed, and a high-temperature fluid corresponding to the exhaust temperature in a high-temperature region. A high temperature heat pipe in which the medium is sealed, and an exhaust temperature including an upper limit temperature at which the low temperature heat pipe can be transported by heat and a lower limit temperature at which the high temperature heat pipe can be transported by heat. The vaporization control means is configured to suppress vaporization of the low-temperature fluid medium or / and to promote vaporization of the high-temperature fluid medium when the exhaust temperature is in the intermediate temperature range with the enclosure being an intermediate temperature range. It is characterized by.

The cryogenic fluid medium can be, for example, water or naphthalene.
The hot fluid medium can be, for example, sodium.
Suppressing the vaporization of the low-temperature fluid medium means suppressing the vaporization of the low-temperature fluid medium by increasing the thermal energy necessary for vaporization or increasing the boiling point.
To promote the vaporization of the high-temperature fluid medium means to promote the vaporization of the high-temperature fluid medium by reducing the heat energy necessary for vaporization or lowering the boiling point.

According to the present invention, an increase in the number of heat pipes can be suppressed and a wide exhaust temperature range can be accommodated.
Specifically, in the state where the heat pipe for low temperature is not transporting heat, when the exhaust temperature is in the intermediate temperature range, the exhaust heat recovery device of the engine can be The temperature at which the pipe starts heat transport and the temperature at which heat transport is stopped can be increased as compared with the case where vaporization is not suppressed.

  Alternatively, when the exhaust pipe temperature is in the intermediate temperature range while the low-temperature heat pipe is in heat transport, the exhaust heat recovery device of the engine suppresses the low-temperature heat by increasing the exhaust temperature by suppressing vaporization of the low-temperature fluid medium. The temperature at which the heat transport of the pipe stops can be raised as compared with the case where the vaporization is not suppressed.

  That is, when the exhaust gas temperature is in the intermediate temperature range, the engine exhaust heat recovery device changes the operating temperature range of the low temperature heat pipe to slide to the high temperature side by the vaporization control means that suppresses the vaporization of the low temperature fluid medium. Alternatively, the operating temperature range of the low temperature heat pipe can be expanded to the high temperature side.

  For this reason, the exhaust heat recovery device of the engine can cause heat transport to the low-temperature heat pipe in the intermediate temperature range. Furthermore, for example, when the exhaust temperature reaches an intermediate temperature range, the exhaust heat recovery device of the engine controls the vaporization of the heat transport by the low temperature heat pipe even if the heat transport of the low temperature heat pipe is stopped. It can be resumed by means.

  On the other hand, when the exhaust gas temperature is in the intermediate temperature range when the heat pipe for high temperature is not transporting heat, the exhaust heat recovery device of the engine is heated by the heat pipe for high temperature by promoting the vaporization of the high temperature fluid medium. The temperature at which the transportation is started and the temperature at which the heat transportation is stopped can be lowered as compared with the case where vaporization is not promoted.

  Alternatively, when the exhaust pipe temperature is in the intermediate temperature range while the heat pipe for high temperature is in heat transport, the exhaust heat recovery device of the engine promotes the high temperature heat The temperature at which the heat transport of the pipe stops can be lowered compared to the case where vaporization is not promoted.

  That is, when the exhaust gas temperature is in the intermediate temperature range, the exhaust heat recovery device of the engine changes the operating temperature range of the high-temperature heat pipe to slide to the low temperature side by the vaporization control means that promotes vaporization of the high-temperature fluid medium. Alternatively, the operating temperature range of the high temperature heat pipe can be expanded to the low temperature side.

  For this reason, the exhaust heat recovery device of the engine can cause the high temperature heat pipe to transport heat in the intermediate temperature range. Furthermore, for example, when the exhaust gas temperature reaches an intermediate temperature range, the exhaust heat recovery device of the engine controls the vaporization of the heat transport by the high temperature heat pipe even if the heat transport of the high temperature heat pipe is stopped. It can be resumed by means.

  As a result, the exhaust heat recovery device of the engine recovers the heat of the exhaust gas in the intermediate temperature range with the low temperature heat pipe and / or the high temperature heat pipe in the process where the exhaust temperature rises or the exhaust temperature falls. can do.

Further, by simultaneously performing the vaporization suppression of the low temperature fluid medium and promoting the vaporization of the high temperature fluid medium, the exhaust heat recovery device of the engine converts the heat of the exhaust gas in the intermediate temperature range into a low temperature heat pipe and a high temperature heat pipe. And can be continuously collected without interruption.
Therefore, the exhaust heat recovery device of the engine can cope with a wide exhaust temperature range by suppressing the increase in the number of heat pipes by the vaporization control means.

  As an aspect of the present invention, the range of the exhaust temperature between the upper limit temperature at which the low temperature heat pipe can be heat transported and the lower limit temperature at which the high temperature heat pipe can be heat transported is set as the low temperature side. And a range expanded by a predetermined temperature on the high temperature side.

  According to this invention, before the exhaust temperature reaches the upper limit temperature of the operating temperature range of the low temperature heat pipe or the lower limit temperature of the operating temperature range of the high temperature heat pipe, the vaporization control means starts suppressing the vaporization of the low temperature fluid medium. Or / and can initiate accelerated vaporization of the hot fluid medium.

  Therefore, before the exhaust temperature reaches the upper limit temperature of the operating temperature range of the low temperature heat pipe or the lower limit temperature of the operating temperature range of the high temperature heat pipe, the exhaust heat recovery device of the engine operates the low temperature heat pipe. The temperature range can be expanded to the high temperature side and / or the operating temperature range of the high temperature heat pipe can be expanded to the low temperature side.

  In other words, the engine exhaust heat recovery device is configured to provide heat transport by the low temperature heat pipe between the upper limit temperature of the operating temperature range of the low temperature heat pipe and the lower limit temperature of the operating temperature range of the high temperature heat pipe, and It is possible to prevent the heat transport by the high temperature heat pipe from stopping.

  Therefore, the exhaust heat recovery device of the engine makes the heat of the exhaust gas in the intermediate temperature range more continuous with the low temperature heat pipe and / or the high temperature heat pipe in the process where the exhaust temperature rises or the exhaust temperature falls. Can be recovered automatically.

  Further, as an aspect of the present invention, the vaporization control unit that suppresses vaporization of the low-temperature fluid medium is configured by a cooling unit that cools the low-temperature fluid medium in a liquid phase, or the inside of the low-temperature heat pipe is added. It is comprised by the pressurization means to press, or is comprised by the increase means which increases the medium amount of the said low-temperature fluid medium in the said low temperature heat pipe.

According to the present invention, the exhaust heat recovery device for an engine can reliably recover the heat of the exhaust gas in the intermediate temperature range with the low-temperature heat pipe.
Specifically, when the vaporization control means that suppresses the vaporization of the cryogenic fluid medium is constituted by a cooling means or an increase means, the exhaust heat recovery device of the engine generates thermal energy necessary for vaporizing the cryogenic fluid medium. , Can be larger than when cooling or not increasing.

  Further, when the vaporization control means that suppresses vaporization of the low-temperature fluid medium is configured by a pressurizing means, the exhaust heat recovery device of the engine can raise the boiling point of the low-temperature fluid medium as compared to the case where no pressure is applied. .

Thereby, when the heat pipe for low temperature is not transporting heat, the exhaust heat recovery device of the engine can increase the temperature at which the heat pipe for low temperature starts heat transport and the temperature at which heat transport is stopped.
Alternatively, when the low-temperature heat pipe is in heat transport, the exhaust heat recovery device of the engine can reduce the vaporization rate of the low-temperature fluid medium, so that the heat transport of the low-temperature heat pipe stops due to an increase in the exhaust temperature. The temperature can be raised.

  For this reason, the exhaust heat recovery device of the engine is changed to slide the operating temperature range of the low temperature heat pipe to the high temperature side by the vaporization control means constituted by the cooling means, the pressurizing means, or the increasing means, or The operating temperature range of the low temperature heat pipe can be expanded to the high temperature side.

  Therefore, the exhaust heat recovery device of the engine can reliably recover the heat of the exhaust gas in the intermediate temperature range with the low-temperature heat pipe by configuring the vaporization control means by the cooling means, the pressurizing means, or the increasing means. Can do.

  Further, as an aspect of the present invention, the vaporization control means for promoting vaporization of the high-temperature fluid medium is configured by a heating means for heating the high-temperature fluid medium in a liquid phase, or the inside of the high-temperature heat pipe is depressurized. Pressure reducing means for reducing the amount of the medium of the high-temperature fluid medium in the high-temperature heat pipe.

According to this invention, the exhaust heat recovery device of the engine can reliably recover the heat of the exhaust gas in the intermediate temperature range with the high-temperature heat pipe.
Specifically, when the vaporization control means for promoting the vaporization of the high-temperature fluid medium is configured by a heating means or a weight reduction means, the engine exhaust heat recovery device supplies the thermal energy necessary for vaporizing the high-temperature fluid medium. It can be made smaller compared to the case where it is not heated or reduced.

  Further, when the vaporization control means for promoting the vaporization of the high-temperature fluid medium is configured by a decompression means, the exhaust heat recovery device of the engine can lower the boiling point of the high-temperature fluid medium as compared with the case where the pressure is not reduced.

Thereby, when the heat pipe for high temperature is not transporting heat, the exhaust heat recovery device of the engine can lower the temperature at which the heat pipe for high temperature starts heat transport and the temperature at which heat transport is stopped.
Alternatively, when the high temperature heat pipe is in heat transport, the exhaust heat recovery device of the engine can lower the temperature at which the heat transport of the high temperature heat pipe stops due to a decrease in the exhaust temperature.

  For this reason, the exhaust heat recovery device of the engine changes the operating temperature range of the high-temperature heat pipe to slide to the low temperature side by the vaporization control means constituted by the heating means, the decompression means, or the weight reduction means, or the high temperature The operating temperature range of the heat pipe can be expanded to the low temperature side.

  Therefore, the exhaust heat recovery device of the engine can reliably recover the heat of the exhaust gas in the intermediate temperature range with the high-temperature heat pipe by configuring the vaporization control means with the heating means, the decompression means, or the weight reduction means. it can.

As an aspect of the present invention, in the exhaust passage, the low temperature heat pipe is disposed downstream of the high temperature heat pipe.
According to this invention, the exhaust heat recovery device for an engine recovers heat of a relatively high temperature exhaust gas with a high temperature heat pipe and recovers a relatively low temperature exhaust gas with a low temperature heat pipe in the exhaust passage. be able to.

  Therefore, the exhaust heat recovery device of the engine can cope with a wide exhaust temperature range and can recover the heat of the exhaust gas flowing down the exhaust passage more efficiently.

  According to the present invention, it is possible to provide an engine exhaust heat recovery device capable of suppressing an increase in the number of heat pipes and corresponding to a wide exhaust temperature range.

The block diagram which shows the structure of an engine system. The longitudinal cross-sectional view which shows the longitudinal cross-section of the principal part in an engine system. The block diagram which shows the component in an exhaust heat recovery apparatus. The longitudinal cross-sectional view which shows the longitudinal cross-section of heat pipe vicinity. Explanatory drawing explaining a heat transport characteristic. The flowchart which shows operation | movement of the vaporization suppression means in an exhaust heat recovery apparatus. FIG. 6 is a longitudinal sectional view showing a longitudinal section in the vicinity of a heat pipe in Example 2. The block diagram which shows the component of the waste heat recovery apparatus in Example 2. FIG. FIG. 6 is a longitudinal sectional view showing a longitudinal section in the vicinity of a heat pipe in Embodiment 3. FIG. 9 is a block diagram illustrating components of an exhaust heat recovery apparatus according to a third embodiment. Explanatory drawing explaining the intermediate temperature range in another embodiment.

  An embodiment of the present invention will be described below with reference to the drawings.

The engine system 1 in this embodiment will be described in detail with reference to FIGS.
1 shows a configuration diagram of the engine system 1, FIG. 2 shows a longitudinal sectional view of a main part of the engine system 1, FIG. 3 shows a block diagram of components in the exhaust heat recovery device 70, and FIG. The longitudinal cross-sectional view of the heat pipe vicinity is shown, and FIG. 5 has shown explanatory drawing explaining a heat transport characteristic curve.

In FIG. 4, the left side in the figure is the combustion chamber C side, the right side in the figure is the catalyst 52 side, the arrow X in the figure is the exhaust gas flowing direction, and the arrow Y is the supercritical water or subcritical water flowing direction. And
FIG. 5A shows an explanatory diagram for explaining the heat transport characteristics in the process of increasing the exhaust temperature, and FIG. 5B shows an explanatory diagram for explaining the heat transport characteristics in the process of decreasing the exhaust temperature. Yes.

  As shown in FIG. 1, the engine system 1 includes an engine 10 that receives a supply of fuel containing gasoline and outputs a driving force, an intake device 20 that supplies outside air to the engine 10, and an injection supply of fuel to the engine 10. Fuel supply device 30, water supply device 40 that supplies supercritical water or subcritical water to engine 10, exhaust device 50 that exhausts exhaust gas discharged from engine 10, and part of the exhaust gas Are recirculated to the intake device 20 and an exhaust heat recovery device 70 that recovers the heat of the exhaust gas.

As shown in FIGS. 1 and 2, the engine 10 is a four-cylinder engine having, for example, four pistons 13 and is configured to output a driving force by compression self-ignition.
Specifically, as shown in FIG. 2, the engine 10 includes a cylinder block 11 in which a cylinder 11a is formed, a cylinder head 12 placed on the cylinder block 11, a piston 13 accommodated in the cylinder 11a, and the like. It is configured.

Further, in the engine 10, the pent roof type combustion chamber C is formed by the cylinder 11 a of the cylinder block 11, the upper surface of the piston 13, and the inclined lower surface of the cylinder head 12.
The top surface of the piston 13 is recessed so as to occupy most of the volume of the combustion chamber C when it rises to top dead center.

  As shown in FIG. 2, the cylinder block 11 is formed with a water jacket 14 that is close to the cylinder 11 a in which the piston 13 is accommodated and in which the cooling water W that cools the engine 10 flows.

  On the other hand, as shown in FIG. 2, the cylinder head 12 is supplied with an intake port 15 that is a hollow space for introducing outside air supplied through the intake device 20 into the combustion chamber C, and exhaust gas generated in the combustion chamber C. An exhaust port 16 that is a hollow space to be discharged is formed.

The cylinder head 12 further includes an intake valve 17 that opens and closes an opening that is a boundary between the intake port 15 and the combustion chamber C, and an opening that is a boundary between the exhaust port 16 and the combustion chamber C. Is provided with an exhaust valve 18 that opens and closes in conjunction with the movement of the piston 13.
The intake port 15 and the exhaust port 16 are each formed in a shape that is inclined obliquely upward and outward from the combustion chamber C in a sectional view.

In addition, as shown in FIG. 1, the intake device 20 includes an internal hollow intake pipe 21 through which external air can flow, and an intake manifold 22 that supplies the external air introduced through the intake pipe 21 to each intake port 15 of the engine 10. (Hereinafter referred to as intake manifold 22).
Furthermore, an air cleaner 23 that removes dust contained in the outside air and a throttle valve 24 that adjusts the flow rate of the outside air are connected to the intake pipe 21 in this order from the upstream side.

  The fuel supply device 30 has a function of pumping fuel stored in a fuel tank (not shown) to the engine 10 and a function of injecting pumped fuel into the combustion chamber C in accordance with the movement of each piston 13. have.

  Specifically, as shown in FIG. 1, the fuel supply device 30 includes a fuel tank that stores fuel containing gasoline, a fuel pump (not shown) that pumps fuel, and fuel injection that injects fuel into the combustion chamber C. Injector 31, a fuel pipe (not shown) for connecting them, a fuel pump, and an engine control unit (hereinafter referred to as ECU) for controlling the operation of fuel injector 31.

As shown in FIG. 2, the fuel injection injector 31 is disposed on the cylinder head 12 so as to face the upper surface of the piston 13 and to have its tip projecting into the combustion chamber C.
The ECU injects fuel for each combustion chamber C according to the operation of each piston 13, and the mixture of the outside air and fuel supplied to the combustion chamber C is compressed and ignited near the top dead center of the piston 13. In addition, the injection timing of the fuel injector 31 is controlled.

  Further, the water supply device 40 has a function of taking out water vapor contained in the exhaust gas as condensed water, a function of heating and pressurizing the condensed water to generate supercritical water or subcritical water, and supercritical water or subcritical water. A function of injecting and supplying water to the combustion chamber C.

  The supercritical water or the subcritical water is vaporized and expanded in the combustion chamber C, and acts as an engine output. That is, the water supply device 40 has a function of suppressing fuel consumption by using supercritical water or subcritical water without reducing engine output.

  Specifically, as shown in FIG. 1, the water supply device 40 is provided downstream of the exhaust device 50, a condenser 41 that condenses water vapor contained in the exhaust gas, and a condensed water tank 42 that stores condensed water. A low pressure pump 43 that pumps the condensed water in the condensed water tank 42, a heat exchanger 44 that raises the temperature of the condensed water, a high pressure pump 45 that pumps the heated condensed water to the engine 10, and the condensed water. A water injection injector 46 that injects into the combustion chamber C, a water supply pipe 47 that connects these, and an ECU that controls the operation of the water injection injector 46 are configured.

  The condenser 41 is integrally disposed on the downstream side of the exhaust device 50 (downstream of a catalyst 52 of the exhaust device 50 described later), and is configured to allow exhaust gas to flow down. The condenser 41 is configured to condense water vapor contained in the exhaust gas so as to be taken out as condensed water.

  The condensed water tank 42 is connected to the condenser 41 through a water supply pipe 47. The condensed water tank 42 is configured so that the condensed water supplied from the condenser 41 via the water supply pipe 47 can be temporarily stored.

  The low-pressure pump 43 is connected to the condensed water tank 42 through a water supply pipe 47 and is connected to the heat exchanger 44 through the water supply pipe 47. The low-pressure pump 43 has a function of pumping condensed water from the condensed water tank 42 to the heat exchanger 44.

  The heat exchanger 44 is integrally disposed in the exhaust device 50 upstream of the condenser 41, and is configured to allow exhaust gas to flow down. Furthermore, a part of the water supply pipe 47 is installed in the heat exchanger 44 so that heat can be exchanged between the high-temperature exhaust gas and low-temperature condensed water with respect to the exhaust gas.

  The high-pressure pump 45 is connected to the heat exchanger 44 through the water supply pipe 47 and is connected to the water injection injector 46 through the water supply pipe 47. The high pressure pump 45 has a function of pressurizing the condensed water heated by the heat exchanger 44 at a pressure higher than that of the low pressure pump 43 and supplying the condensed water to the water injection injector 46 as supercritical water or subcritical water. doing.

As shown in FIG. 2, the water injection injector 46 is disposed in the vicinity of the boundary between the cylinder block 11 and the cylinder head 12 so that the tip thereof protrudes from the side to the combustion chamber C. The water injector 46 has the same configuration as the fuel injector 31, for example.
In the water injection injector 46, the injection timing for injecting supercritical water or subcritical water is controlled by the ECU, similarly to the fuel injection injector 31.

  Further, as shown in FIG. 1, the exhaust device 50 includes an exhaust manifold 51 (hereinafter referred to as an exhaust manifold 51) connected to the cylinder block 11 and a catalyst that purifies harmful substances in the exhaust gas discharged from the engine 10. 52 and an internal hollow exhaust pipe 53 that connects these components and discharges exhaust gas to the outside of the vehicle.

Furthermore, the heat exchanger 44 and the condenser 41 of the water supply device 40 described above are connected to the exhaust device 50 in this order in the exhaust pipe 53 downstream of the catalyst 52.
As shown in FIG. 2, the exhaust manifold 51 is formed with an exhaust manifold exhaust passage 51 a that is an internal space communicating with each exhaust port 16 and communicating with the exhaust pipe 53. For example, exhaust gas of 150 ° C. to 800 ° C. flows down into the exhaust manifold exhaust passage 51a.

Further, as shown in FIG. 3, the exhaust manifold 51 is electrically connected to the ECU 2 and is provided with an exhaust temperature sensor 54 that detects an exhaust temperature that is the temperature of the exhaust gas flowing down the exhaust manifold exhaust passage 51 a. ing.
In addition, as shown in FIG. 2, the exhaust manifold 51 is formed with an exhaust manifold water supply passage 47 a that is a part of the water supply pipe 47 in the water supply device 40 above the exhaust manifold exhaust passage 51 a.

  The catalyst 52 is, for example, a three-dimensional catalyst, and removes harmful substances such as nitrogen oxide (NOx), carbon monoxide (CO), and hydrocarbon (HC) contained in the exhaust gas discharged from the engine 10. It is configured to be purifiable.

The catalyst 52 is activated, for example, at 200 ° C. or higher and exhibits a purification function in a predetermined temperature range.
Further, as shown in FIG. 3, the catalyst 52 is electrically connected to the ECU 2 and is provided with a catalyst temperature sensor 55 that detects the catalyst temperature that is the temperature of the catalyst 52.

  The exhaust port 16 of the engine 10, the exhaust manifold 51, the catalyst 52, the heat exchanger 44, the condenser 41, and the exhaust pipe 53 that connects them, and an integrated interior in which the exhaust gas can flow down. The space is an exhaust passage through which exhaust gas flows.

  As shown in FIG. 1, the EGR device 60 includes an exhaust shutter valve 61 provided in the exhaust pipe 53, an EGR pipe 62 connecting the exhaust pipe 53 and the intake pipe 21, and an EGR valve 63 provided in the EGR pipe 62. And an EGR cooler 64, an exhaust shutter valve 61, and an ECU that controls the operation of the EGR valve 63.

The exhaust shutter valve 61 is configured as a freely openable open / close valve provided in the exhaust pipe 53 downstream of the condenser 41. The exhaust shutter valve 61 is controlled to open and close by the ECU, and closes to close the inside of the exhaust pipe 53 when the internal pressure of the exhaust pipe 53 is low.
The EGR pipe 62 is configured to connect the exhaust pipe 53 between the exhaust manifold 51 and the catalyst 52 and the intake pipe 21 between the throttle valve 24 and the intake manifold 22 so that they can communicate with each other.

  The EGR valve 63 is configured by an openable on-off valve provided inside the EGR pipe 62. The EGR valve 63 has a function of adjusting the amount of exhaust gas recirculated to the intake device 20 by being controlled to open and close by the ECU.

  The EGR cooler 64 is disposed upstream of the EGR valve 63, that is, adjacent to the intake pipe 21 side. The EGR cooler 64 has a function of cooling the exhaust gas recirculated to the intake device 20.

  Further, as shown in FIGS. 1 to 3, the exhaust heat recovery apparatus 70 has a substantially loop-shaped high-temperature heat pipe 71 sealed with the high-temperature heat exchange medium M1 and a low-temperature heat exchange medium M2 sealed. The heat pipe 72 for low temperature of substantially loop shape, and the vaporization control means 73 which controls vaporization of the heat exchange medium M1 for high temperature and the heat exchange medium M2 for low temperature are comprised.

  The high temperature heat pipe 71 and the low temperature heat pipe 72 are each formed of a metal pipe member having high thermal conductivity. As shown in FIGS. 2 and 4, the high temperature heat pipe 71 and the low temperature heat pipe 72 span between the exhaust manifold exhaust passage 51 a and the exhaust manifold water supply passage 47 a and follow the inclination of the exhaust port 16. It is embedded in the exhaust manifold 51 in an inclined state.

  More specifically, the high-temperature heat pipe 71 is arranged upstream of the exhaust manifold exhaust passage 51a close to the exhaust port 16, as shown in FIG. The high-temperature heat pipe 71 is disposed in the heat absorption part 71a exposed to the exhaust gas, the exhaust manifold water supply passage 47a, the heat dissipation part 71b exposed to the supercritical water or the subcritical water, and the downstream of the exhaust manifold exhaust passage 51a. A steam passage portion 71c that connects the heat absorption portion 71a and the heat dissipation portion 71b on the side, and a reflux passage portion 71d that connects the heat absorption portion 71a and the heat dissipation portion 71b on the upstream side of the exhaust manifold exhaust passage 51a. Is formed.

Furthermore, a reservoir tank 74 that stores the high-temperature heat exchange medium M1 is integrally formed with the high-temperature heat pipe 71.
As shown in FIG. 4, the reservoir tank 74 has a substantially box shape made of metal and is integrally formed so as to be able to communicate with the heat absorbing portion 71 a of the heat pipe 71 for high temperature.

  The high-temperature heat exchange medium M1 is a fluid medium capable of heat transport in a high-temperature range that is a high-temperature exhaust temperature range, and a predetermined amount that fills a part of the heat-absorbing portion 71a and the reservoir tank 74 is high-temperature heat. The pipe 71 is sealed.

More specifically, as shown in FIG. 5, the high-temperature heat exchange medium M1 has a relatively high exhaust gas temperature at a heat transport characteristic curve TH1 (thin solid line in FIG. 5) showing the relationship between the heat transport amount and the exhaust gas temperature. It is a fluid medium obtained in the high temperature range which is the range of. In addition, let the range of the exhaust temperature of the high temperature range from which the heat transport characteristic curve TH1 is obtained be the operating temperature range of the heat pipe 71 for high temperature.
As this high-temperature heat exchange medium M1, for example, sodium having an operating temperature range of 600 ° C. to 1200 ° C. is used.

  When the high-temperature heat pipe 71 having such a configuration is exposed to high-temperature exhaust gas, the high-temperature heat exchange medium M1 is vaporized and evaporated by the heat exchange with the exhaust gas in the heat-absorbing portion 71a. Become. Thereafter, the high-temperature heat exchange medium M1 in the vapor phase moves to the heat radiating portion 71b via the vapor passage portion 71c, and is condensed by the heat exchange with the supercritical water or the subcritical water, and shifts to the liquid phase state.

  Then, the high-temperature heat exchange medium M1 that has shifted to the liquid phase state returns to the heat absorbing portion 71a via the reflux passage portion 71d, and again shifts to the gas phase state by heat exchange with the exhaust gas. As described above, when the high temperature heat pipe 71 is exposed to the exhaust gas in the high temperature region, the high temperature heat exchange medium M1 continuously evaporates and condenses, so that the exhaust manifold supply passage from the exhaust manifold exhaust passage 51a. Heat transport to 47a.

  2 and 4, the low temperature heat pipe 72 has substantially the same structure as the high temperature heat pipe 71, and is disposed downstream of the high temperature heat pipe 71 in the exhaust manifold exhaust passage 51a.

  As shown in FIG. 4, the low-temperature heat pipe 72 includes a heat-absorbing part 72a exposed to exhaust gas, a heat-dissipating part 72b exposed to supercritical water or subcritical water, and an exhaust manifold exhaust. The steam passage portion 72c located on the downstream side of the passage 51a and the reflux passage portion 72d located on the upstream side of the exhaust manifold exhaust passage 51a are formed in a substantially rectangular loop shape.

Further, a reservoir tank 75 for storing the low-temperature heat exchange medium M2 is integrally formed with the low-temperature heat pipe 72.
As shown in FIG. 4, the reservoir tank 75 has a substantially box shape made of metal and is integrally formed so as to be able to communicate with the heat absorbing portion 72 a of the low-temperature heat pipe 72.

  The low-temperature heat exchange medium M2 is a fluid medium capable of heat transport in a low temperature range, which is an exhaust temperature range lower than the high temperature range, and has a predetermined amount that fills a part of the heat absorbing portion 72a and the reservoir tank 75. The heat pipe 72 for low temperature is sealed.

More specifically, as shown in FIG. 5, the heat exchange medium M2 for low temperature has a heat transport characteristic curve TL1 (thin solid line in FIG. 5) showing the relationship between the heat transport amount and the exhaust temperature, which is lower than the high temperature region. It is a fluid medium obtained in a low temperature range. In addition, let the range of the exhaust temperature in the low temperature range from which the heat transport characteristic curve TL1 is obtained be the operating temperature range of the heat pipe 72 for low temperature.
As the low-temperature heat exchange medium M2, for example, pure water having an operating temperature range of 30 ° C. to 250 ° C. is used.

  When the low-temperature heat pipe 72 having such a configuration is exposed to the low-temperature exhaust gas, the low-temperature heat exchange medium M2 is vaporized and evaporated by the heat exchange with the exhaust gas in the heat-absorbing part 72a to be in a gas phase state. Become. Thereafter, the low-temperature heat exchange medium M2 in the vapor phase moves to the heat radiating portion 72b via the vapor passage portion 72c, and is condensed by the heat exchange with the supercritical water or the subcritical water, and shifts to the liquid phase state.

  The low-temperature heat exchange medium M2 that has transitioned to the liquid phase returns to the heat absorption section 72a via the reflux passage section 72d, and then transitions again to the gas phase by heat exchange with the exhaust gas. As described above, when the low temperature heat pipe 72 is exposed to the exhaust gas in the low temperature region, the low temperature heat exchange medium M2 continuously repeats evaporation and condensation, so that the exhaust manifold supply passage from the exhaust manifold exhaust passage 51a. Heat transport to 47a.

  Note that the temperature range between the lower limit temperature of the operating temperature range in the high temperature heat pipe 71 and the upper limit temperature of the operating temperature range in the low temperature heat pipe 72 is a range in which the temperature range is expanded by a predetermined temperature on the low temperature side and the high temperature side. An intermediate temperature range R is set (see FIG. 5).

In the intermediate temperature range R, the vaporization control means 73 has a function of promoting vaporization of the high temperature heat exchange medium M1 and a function of suppressing vaporization of the low temperature heat exchange medium M2.
As shown in FIGS. 3 and 4, the vaporization control unit 73 includes a heating unit 76 that heats the high-temperature heat exchange medium M1, a cooling unit 77 that cools the low-temperature heat exchange medium M2, an exhaust temperature sensor 54, and the like. The ECU 2 controls these operations.

  The heating unit 76 is mounted on the lower surface of the reservoir tank 74 in the high-temperature heat pipe 71, and is configured by, for example, an electric heater. The heating unit 76 is electrically connected to the ECU 2, and the heating operation of the high-temperature heat exchange medium M <b> 1 and the stop of the heating operation are controlled by the ECU 2. The heating unit 76 is controlled to be in a state where the heating operation is stopped immediately after the engine is started.

  The cooling unit 77 is attached to the lower surface of the reservoir tank 75 in the low-temperature heat pipe 72, and is composed of a thermoelectric element such as a Peltier element, for example. The cooling unit 77 is electrically connected to the ECU 2 and the cooling operation of the low-temperature heat exchange medium M2 and the stop of the cooling operation are controlled by the ECU 2. The cooling unit 77 is controlled to be in a state where the cooling operation is stopped immediately after the engine is started.

Next, operation | movement of the vaporization control means 73 in the waste heat recovery apparatus 70 of the structure mentioned above is demonstrated using FIG.
FIG. 6 shows a flowchart of the vaporization control means 73 in the exhaust heat recovery apparatus 70.

When the engine is started by the occupant's operation, the ECU 2 of the vaporization control means 73 acquires the exhaust temperature detected by the exhaust temperature sensor 54 at predetermined time intervals (step S101), and whether or not the acquired exhaust temperature is within the intermediate temperature range R. (Step S102)
If the acquired exhaust temperature is not within the intermediate temperature range R (step S102: No), the ECU 2 determines that heat is being transported by the high temperature heat pipe 71 or the low temperature heat pipe 72, and step S101. Return to.

In step S102, when the acquired exhaust temperature is within the intermediate temperature range R (step S102: Yes), the vaporization control means 73 starts heating the high-temperature heat exchange medium M1 and cooling the low-temperature heat exchange medium M2. (Step S103).
Specifically, the ECU 2 of the vaporization control unit 73 starts supplying power to the electric heater of the heating unit 76 and the thermoelectric element of the cooling unit 77.

  The heating unit 76 supplied with power heats the high-temperature heat exchange medium M1 in a liquid phase by starting a heating operation. Similarly, the cooling unit 77 supplied with power cools the low-temperature heat exchange medium M2 in the liquid phase by starting the cooling operation.

  In this way, by heating the high-temperature heat exchange medium M1 and cooling the low-temperature heat exchange medium M2, the exhaust heat recovery device 70 has the heat transport characteristic curve of the high-temperature heat exchange medium M1 shown in FIG. Like the heat transport characteristic curve TL2 of TH2 and the low temperature heat exchange medium M2, the operating temperature range of the high temperature heat exchange medium M1 and the operating temperature range of the low temperature heat exchange medium M2 are changed.

  More specifically, when the exhaust temperature rises from the low temperature range to the intermediate temperature range R, the high temperature heat pipe 71 does not carry out heat transportation, and the low temperature heat pipe 72 carries out heat transportation. .

  For this reason, the operating temperature range of the heated high-temperature heat exchange medium M1 is the operation of the unheated high-temperature heat exchange medium M1 as shown in the heat transport characteristic curve TH2 shown by the thick solid line in FIG. It changes so that the whole region may slide to the low temperature side with respect to the temperature range.

  On the other hand, the operating temperature range of the cooled low-temperature heat exchange medium M2 is the operating temperature of the uncooled low-temperature heat exchange medium M2 as shown in the heat transport characteristic curve TL2 indicated by the thick solid line in FIG. The upper limit temperature of the operating temperature range is dynamically changed to the high temperature side with respect to the range.

  Further, when the exhaust temperature is lowered from the high temperature range to the intermediate temperature range R, the high temperature heat pipe 71 is transporting, and the low temperature heat pipe 72 is not transporting heat.

  For this reason, the operating temperature range of the heated high-temperature heat exchange medium M1 is the operation of the unheated high-temperature heat exchange medium M1 as shown in the heat transport characteristic curve TH2 indicated by the thick solid line in FIG. The lower limit temperature of the operating temperature range is dynamically changed to the low temperature side with respect to the temperature range.

On the other hand, the operating temperature range of the cooled low-temperature heat exchange medium M2 is the operating temperature of the uncooled low-temperature heat exchange medium M2 as shown in the heat transport characteristic curve TL2 indicated by the thick solid line in FIG. It changes so that the whole region may slide to the high temperature side with respect to the range.
In this way, the exhaust heat recovery apparatus 70 performs heat transport by the high temperature heat pipe 71 and heat transport by the low temperature heat pipe 72 in the intermediate temperature range R.

  Thereafter, the ECU 2 of the vaporization control means 73 acquires the exhaust temperature detected by the exhaust temperature sensor 54 (step S104), and determines whether or not the acquired exhaust temperature is within the intermediate temperature range R (step S105).

  When the acquired exhaust temperature is within the intermediate temperature range R (step S105: Yes), the ECU 2 returns to step S104 and repeats steps S104 and S105 until the acquired exhaust temperature is not within the intermediate temperature range R.

On the other hand, if the acquired exhaust temperature is not within the intermediate temperature range R (step S105: No), the vaporization control means 73 stops heating the high temperature heat exchange medium M1 and cooling the low temperature heat exchange medium M2 (step S105). S106).
Specifically, the ECU 2 of the vaporization control means 73 stops the power supply to the heating unit 76 and the cooling unit 77 and stops the heating operation of the heating unit 76 and the cooling operation of the cooling unit 77.

As a result, the exhaust heat recovery apparatus 70 is configured so that the high-temperature heat exchange medium as shown in the heat-transport characteristic curve TH1 of the high-temperature heat exchange medium M1 and the low-temperature heat-exchange medium M2 shown in FIG. The operating temperature range of M1 and the operating temperature range of the low-temperature heat exchange medium M2 are restored.
Thereafter, the ECU 2 of the vaporization control means 73 returns to step S101 and repeats the above-described steps S101 to S106 until the engine 10 stops.

The exhaust heat recovery device 70 of the engine 10 that realizes the above-described operation can cope with a wide exhaust temperature range while suppressing an increase in the number of heat pipes.
Specifically, when the low temperature heat pipe 72 is not transporting heat and the exhaust temperature is within the intermediate temperature range R, the exhaust heat of the engine 10 is suppressed by suppressing the vaporization of the low temperature heat exchange medium M2. The recovery device 70 can increase the temperature at which the low-temperature heat pipe 72 starts heat transport and the temperature at which heat transport is stopped compared to the case where vaporization is not suppressed.

  Alternatively, when the low temperature heat pipe 72 is in the state of heat transport and the exhaust temperature is within the intermediate temperature range R, the exhaust heat recovery device 70 of the engine 10 can be controlled by suppressing vaporization of the low temperature heat exchange medium M2. The temperature at which the heat transport of the low-temperature heat pipe 72 stops due to the rise in the exhaust temperature can be increased as compared with the case where vaporization is not suppressed.

  That is, when the exhaust gas temperature is within the intermediate temperature range R, the exhaust heat recovery device 70 of the engine 10 sets the operating temperature range of the low temperature heat pipe 72 by the vaporization control means 73 that suppresses the vaporization of the low temperature heat exchange medium M2. It can be changed to slide to the high temperature side, or the operating temperature range of the low temperature heat pipe 72 can be expanded to the high temperature side. For this reason, the exhaust heat recovery device 70 of the engine 10 can cause the low-temperature heat pipe 72 to transport heat in the intermediate temperature range R.

  On the other hand, when the exhaust temperature is within the intermediate temperature range R in a state where the heat pipe 71 for high temperature is not transporting heat, the exhaust heat recovery device 70 of the engine 10 is promoted by promoting the vaporization of the heat exchange medium M1 for high temperature. The temperature at which the high-temperature heat pipe 71 starts heat transport and the temperature at which heat transport stops can be lowered as compared with the case where vaporization is not promoted.

  Alternatively, when the exhaust pipe temperature is in the intermediate temperature range R in a state where the high temperature heat pipe 71 is in heat transport, the exhaust heat recovery device 70 of the engine 10 can be accelerated by promoting vaporization of the high temperature heat exchange medium M1. The temperature at which the heat transport of the high-temperature heat pipe 71 stops due to the decrease in the exhaust temperature can be lowered as compared with the case where vaporization is not promoted.

  That is, when the exhaust temperature is within the intermediate temperature range R, the exhaust heat recovery device 70 of the engine 10 sets the operating temperature range of the high temperature heat pipe 71 by the vaporization control means 73 that promotes vaporization of the high temperature heat exchange medium M1. It can be changed to slide to the low temperature side, or the operating temperature range of the heat pipe 71 for high temperature can be expanded to the low temperature side. For this reason, the exhaust heat recovery device 70 of the engine 10 can cause the high-temperature heat pipe 71 to transport heat in the intermediate temperature range R.

  Thereby, the exhaust heat recovery device 70 of the engine 10 converts the heat of the exhaust gas in the intermediate temperature range R into the low-temperature heat pipe 72 or the high-temperature heat pipe in the process in which the exhaust temperature rises or the exhaust temperature falls. 71 can be recovered.

Further, by simultaneously performing the vaporization suppression of the low temperature heat exchange medium M2 and the promotion of vaporization of the high temperature heat exchange medium M1, the exhaust heat recovery device 70 of the engine 10 reduces the heat of the exhaust gas in the intermediate temperature range R, The low-temperature heat pipe 72 and the high-temperature heat pipe 71 can be continuously collected without interruption.
Therefore, the exhaust heat recovery device 70 of the engine 10 can cope with a wide exhaust temperature range by suppressing the increase in the number of heat pipes by the vaporization control means 73.

  In addition, the range of the exhaust temperature between the upper limit temperature at which the low temperature heat pipe 72 can carry heat and the lower limit temperature at which the high temperature heat pipe 71 can carry heat is expanded by a predetermined temperature to the low temperature side and the high temperature side. By setting the range to the intermediate temperature range R, before the exhaust temperature reaches the upper limit temperature of the operating temperature range of the low temperature heat pipe 72 or the lower limit temperature of the operating temperature range of the high temperature heat pipe 71, the vaporization control means 73. Can start the suppression of the vaporization of the low-temperature heat exchange medium M2 and also start the promotion of the vaporization of the high-temperature heat exchange medium M1.

  For this reason, before the exhaust temperature reaches the upper limit temperature of the operating temperature range of the low temperature heat pipe 72 or the lower limit temperature of the operating temperature range of the high temperature heat pipe 71, the exhaust heat recovery device 70 of the engine 10 The operating temperature range of the heat pipe 72 can be expanded to the high temperature side, and the operating temperature range of the high temperature heat pipe 71 can be expanded to the low temperature side.

  In other words, the exhaust heat recovery device 70 of the engine 10 has a low temperature heat pipe 72 between the upper limit temperature of the operating temperature range of the low temperature heat pipe 72 and the lower limit temperature of the operating temperature range of the high temperature heat pipe 71. It is possible to prevent the heat transport by and the heat transport by the high-temperature heat pipe 71 from stopping.

  Therefore, the exhaust heat recovery device 70 of the engine 10 converts the heat of the exhaust gas in the intermediate temperature range R into the low temperature heat pipe 72 and the high temperature heat pipe 71 in the process in which the exhaust temperature rises or the exhaust temperature falls. Can be recovered more continuously.

  In addition, the cooling unit 77 that cools the low-temperature heat exchange medium M2, the exhaust temperature sensor 54, and the ECU 2 constitute the vaporization control means 73 that suppresses the vaporization of the low-temperature heat exchange medium M2, so that the exhaust heat of the engine 10 is exhausted. The recovery device 70 can reliably recover the heat of the exhaust gas in the intermediate temperature range R with the low-temperature heat pipe 72.

  Specifically, by cooling the low-temperature heat exchange medium M2 in the liquid phase, the exhaust heat recovery device 70 of the engine 10 cools the thermal energy necessary for vaporizing the low-temperature heat exchange medium M2. It can be larger than if it is not.

  Thereby, when the heat pipe 72 for low temperature is not transporting heat, the exhaust heat recovery device 70 of the engine 10 increases the temperature at which the heat pipe 72 for low temperature starts heat transport and the temperature at which heat transport is stopped. Can do.

  Alternatively, when the low-temperature heat pipe 72 is in heat transport, the exhaust heat recovery device 70 of the engine 10 can reduce the vaporization rate of the low-temperature heat exchange medium M2, so that the low-temperature heat pipe is increased by increasing the exhaust temperature. The temperature at which the heat transport of 72 stops can be raised.

  For this reason, the exhaust heat recovery device 70 of the engine 10 is changed so that the operating temperature range of the low-temperature heat pipe 72 is slid to the high temperature side by the vaporization control means 73 that cools the low-temperature heat exchange medium M2 in the liquid phase. Alternatively, the operating temperature range of the low temperature heat pipe 72 can be expanded to the high temperature side.

  Therefore, the exhaust heat recovery device 70 of the engine 10 ensures that the heat of the exhaust gas in the intermediate temperature range R is reliably transmitted by the low temperature heat pipe 72 by the vaporization control means 73 that cools the low temperature heat exchange medium M2 in the liquid phase. It can be recovered.

  Further, the heating unit 76 that heats the high-temperature heat exchange medium M1, the exhaust temperature sensor 54, and the ECU 2 constitute the vaporization control means 73 that promotes the vaporization of the high-temperature heat exchange medium, thereby recovering the exhaust heat of the engine 10. The device 70 can reliably recover the heat of the exhaust gas in the intermediate temperature range R by the high-temperature heat pipe 71.

  Specifically, by heating the high-temperature heat exchange medium M1 in the liquid phase, the exhaust heat recovery device 70 of the engine 10 heats the heat energy necessary for vaporizing the high-temperature heat exchange medium M1. It can be made smaller compared to when not.

Thereby, when the heat pipe 71 for high temperature is not transporting heat, the exhaust heat recovery device 70 of the engine 10 lowers the temperature at which the heat pipe 71 for high temperature starts heat transport and the temperature at which heat transport is stopped. Can do.
Alternatively, when the high temperature heat pipe 71 is in heat transport, the exhaust heat recovery device 70 of the engine 10 can lower the temperature at which the heat transport of the high temperature heat pipe 71 stops due to a decrease in the exhaust temperature.

  For this reason, the exhaust heat recovery device 70 of the engine 10 changes the operating temperature range of the high-temperature heat pipe 71 to slide to the low temperature side by the vaporization control means 73 that heats the high-temperature heat exchange medium M1, or the high temperature The operating temperature range of the heat pipe 71 can be expanded to the low temperature side.

  Therefore, the exhaust heat recovery device 70 of the engine 10 can reliably recover the heat of the exhaust gas in the intermediate temperature range R by the high temperature heat pipe 71 by the vaporization control means 73 that heats the high temperature heat exchange medium M1. it can.

  Further, in the exhaust manifold exhaust passage 51a, the low temperature heat pipe 72 is disposed downstream of the high temperature heat pipe 71, so that the exhaust heat recovery device 70 of the engine 10 is disposed in the exhaust manifold exhaust passage 51a. The heat of the relatively high temperature exhaust gas can be recovered by the high temperature heat pipe 71, and the heat of the relatively low temperature exhaust gas can be recovered by the low temperature heat pipe 72.

  Therefore, the exhaust heat recovery device 70 of the engine 10 can cope with a wide exhaust temperature range, and can more efficiently recover the heat of the exhaust gas flowing down the exhaust manifold exhaust passage 51a.

Exhaust heat recovery apparatus 80 having a different vaporization suppression means compared to the first embodiment will be described in detail with reference to FIGS. 7 and 8.
7 shows a longitudinal sectional view of the vicinity of the heat pipe in the second embodiment, and FIG. 8 shows a block diagram of the exhaust heat recovery apparatus 80 in the second embodiment.

Further, in FIG. 7, the left side in the figure is the combustion chamber C side, the right side in the figure is the catalyst 52 side, the arrow X in the figure is the exhaust gas flow direction, and the arrow Y is the supercritical water or subcritical water flow direction. And
The same configurations as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 7 and 8, in the exhaust heat recovery apparatus 80 of the second embodiment, the loop-shaped high-temperature heat pipe 81 in which the high-temperature heat exchange medium M1 is sealed and the low-temperature heat exchange medium M2 are sealed. The loop-shaped low-temperature heat pipe 82, and the high-temperature heat exchange medium M1 and the vaporization control means 83 for controlling the vaporization of the low-temperature heat exchange medium M2.

  As shown in FIG. 7, the high temperature heat pipe 81 includes a heat absorption part 81 a exposed to the exhaust gas, a heat radiation part 81 b disposed in the exhaust manifold water supply passage 47 a and exposed to supercritical water or subcritical water, A steam passage portion 81c connecting the heat absorption portion 81a and the heat dissipation portion 81b on the downstream side of the exhaust manifold exhaust passage 51a, and a reflux passage portion 81d connecting the heat absorption portion 81a and the heat dissipation portion 81b on the upstream side of the exhaust manifold exhaust passage 51a. It is formed in a substantially rectangular loop shape.

  Further, as shown in FIG. 7, the high temperature heat pipe 81 is integrally formed with a connecting portion 81e extending upward from the heat radiating portion 81b on the downstream side of the exhaust manifold exhaust passage 51a. This connection part 81e is connected to the opening hole 51b of the exhaust manifold 51 opened by the predetermined magnitude | size.

  7 and 8, the low temperature heat pipe 82 has substantially the same structure as the high temperature heat pipe 81, and is disposed downstream of the high temperature heat pipe 81 in the exhaust manifold exhaust passage 51a.

  As shown in FIG. 7, this low temperature heat pipe 82 is similar to the high temperature heat pipe 81, a heat absorbing portion 82 a exposed to exhaust gas, a heat radiating portion 82 b exposed to supercritical water or subcritical water, and an exhaust manifold exhaust. The steam passage portion 82c located on the downstream side of the passage 51a and the reflux passage portion 82d located on the upstream side of the exhaust manifold exhaust passage 51a are formed in a substantially rectangular loop shape.

  Further, as shown in FIG. 7, the low temperature heat pipe 82 is integrally formed with a connecting portion 82e extending upward from the heat radiating portion 82b on the downstream side of the exhaust manifold exhaust passage 51a. This connection part 82e is connected to the opening hole 51c of the exhaust manifold 51 opened by the predetermined magnitude | size.

  As shown in FIGS. 7 and 8, the vaporization control means 83 includes a decompression unit 84 that decompresses the inside of the high-temperature heat pipe 81, a pressurization unit 85 that pressurizes the inside of the low-temperature heat pipe 82, and an exhaust temperature sensor. 54 and ECU2 which controls these operations.

  As shown in FIG. 7, the decompression unit 84 forms a piston-type pump with an opening hole 51b of the exhaust manifold 51 and a solenoid valve 86 for decompression having a valve having an outer diameter substantially equal to that of the opening hole 51b. It is configured.

  As shown in FIGS. 7 and 8, the pressure reducing electromagnetic valve 86 is constituted by, for example, a solenoid valve. The pressure reducing electromagnetic valve 86 is electrically connected to the ECU 2 and is controlled by the ECU 2 between an ON state in which the plunger protrudes and an OFF state in which the plunger does not protrude. Note that the pressure reducing solenoid valve 86 is controlled to be in an ON state in which the plunger protrudes immediately after the engine is started.

  As shown in FIG. 7, the pressurizing unit 85 forms a piston pump with an opening hole 51 c of the exhaust manifold 51 and a pressurizing electromagnetic valve 87 having a valve having an outer diameter substantially equal to that of the opening hole 51 c at the tip. It is configured as follows.

  As shown in FIGS. 7 and 8, the pressurizing electromagnetic valve 87 is constituted by, for example, a solenoid valve. The pressurizing solenoid valve 87 is electrically connected to the ECU 2 and is controlled by the ECU 2 between an ON state in which the plunger protrudes and an OFF state in which the plunger does not protrude. Note that the pressurizing solenoid valve 87 is controlled to be in an OFF state in which the plunger does not protrude immediately after the engine is started.

Next, the operation of the vaporization control means 83 in the exhaust heat recovery apparatus 80 will be described.
The operation of the vaporization control unit 83 in the exhaust heat recovery apparatus 80 is different from the operation of the vaporization control unit 73 in the first embodiment described above in steps S103 and S106 in FIG. Therefore, here, step S103 in FIG. 6 is replaced with “decompression / pressurization start”, and step S106 is replaced with “decompression / pressurization stop”.

  First, in step S102 of FIG. 6, when the acquired exhaust gas temperature is within the intermediate temperature range R (step S102: Yes), the vaporization control means 83 starts depressurization of the high-temperature heat pipe 81 and low-temperature heat pipe. The pressurization of 82 is started (step S103).

Specifically, the vaporization control means 83 causes the internal pressure of the high temperature heat pipe 81 to be reduced by increasing the volume in the high temperature heat pipe 81 by causing the ECU 2 to turn off the pressure reduction electromagnetic valve 86.
Furthermore, the vaporization control means 83 pressurizes the internal pressure of the low-temperature heat pipe 82 by reducing the volume in the low-temperature heat pipe 82 when the ECU 2 turns on the pressurization electromagnetic valve 87.

  In this way, by reducing the pressure of the high-temperature heat pipe 81 and pressurizing the low-temperature heat pipe 82, the exhaust heat recovery device 80 can operate in the operating temperature range of the high-temperature heat exchange medium M1, as in the first embodiment. And the operating temperature range of the heat exchange medium M2 for low temperature is changed.

  Thereafter, in step S105, when the acquired exhaust temperature is not within the intermediate temperature range R (step S105: No), the vaporization control means 83 stops depressurization of the high temperature heat pipe 81 and pressurization of the low temperature heat pipe 82. (Step S106).

  Specifically, the ECU 2 stops the pressure reducing operation of the pressure reducing unit 84 by turning on the pressure reducing electromagnetic valve 86, and turns off the pressure electromagnetic valve 87 to turn off the pressure applying unit 85. Stop the pressurizing operation.

  As a result, the exhaust heat recovery apparatus 80 is configured so that the high-temperature heat exchange medium as shown in FIG. The operating temperature range of M1 and the operating temperature range of the low-temperature heat exchange medium M2 are restored.

  The exhaust heat recovery device 80 of the engine 10 that realizes the above-described operation can cope with a wide exhaust temperature range while suppressing an increase in the number of heat pipes, as in the first embodiment.

  Further, the vaporization control means 83 that suppresses the vaporization of the low-temperature heat exchange medium M2 is configured by the pressurizing unit 85 that pressurizes the inside of the low-temperature heat pipe 82, the exhaust temperature sensor 54, and the ECU 2. The exhaust heat recovery device 80 can reliably recover the heat of the exhaust gas in the intermediate temperature range R with the low-temperature heat pipe 82.

  Specifically, by pressurizing the inside of the low-temperature heat pipe 82, the exhaust heat recovery device 80 of the engine 10 can raise the boiling point of the low-temperature heat exchange medium M2 as compared to the case where no pressure is applied.

Thereby, when the heat pipe 82 for low temperature is not transporting heat, the exhaust heat recovery device 80 of the engine 10 increases the temperature at which the heat pipe 82 for low temperature starts heat transport and the temperature at which heat transport is stopped. Can do.
Alternatively, when the low temperature heat pipe 82 is in heat transport, the exhaust heat recovery device 80 of the engine 10 can increase the temperature at which the heat transport of the low temperature heat pipe 82 stops due to an increase in the exhaust temperature.

  Therefore, the exhaust heat recovery device 80 of the engine 10 changes the operating temperature range of the low temperature heat pipe 82 to slide to the high temperature side by the vaporization control means 83 that pressurizes the inside of the low temperature heat pipe 82, or The operating temperature range of the low temperature heat pipe 82 can be expanded to the high temperature side.

  Therefore, the exhaust heat recovery device 80 of the engine 10 reliably recovers the heat of the exhaust gas in the intermediate temperature range R by the low temperature heat pipe 82 by the vaporization control means 83 that pressurizes the inside of the low temperature heat pipe 82. Can do.

  Further, the decompression unit 84 that decompresses the inside of the high-temperature heat pipe 81, the exhaust temperature sensor 54, and the ECU 2 constitute the vaporization control means 83 that promotes the vaporization of the high-temperature heat exchange medium M1, thereby reducing the exhaust of the engine 10. The heat recovery device 80 can reliably recover the heat of the exhaust gas in the intermediate temperature range R with the high-temperature heat pipe 81.

  Specifically, by reducing the pressure inside the high-temperature heat pipe 81, the exhaust heat recovery device 80 of the engine 10 can lower the boiling point of the high-temperature heat exchange medium M1 compared to when the pressure is not reduced.

Thereby, when the heat pipe 81 for high temperature is not transporting heat, the exhaust heat recovery device 80 of the engine 10 lowers the temperature at which the heat pipe 81 for high temperature starts heat transport and the temperature at which heat transport is stopped. Can do.
Alternatively, when the high-temperature heat pipe 81 is in heat transport, the exhaust heat recovery device 80 of the engine 10 can lower the temperature at which the heat transport of the high-temperature heat pipe 81 stops due to a decrease in the exhaust temperature.

  For this reason, the exhaust heat recovery device 80 of the engine 10 changes the operating temperature range of the high temperature heat pipe 81 to slide to the low temperature side by the vaporization control means 83 that depressurizes the inside of the high temperature heat pipe 81, or The operating temperature range of the high temperature heat pipe 81 can be expanded to the low temperature side.

  Accordingly, the exhaust heat recovery device 80 of the engine 10 reliably recovers the heat of the exhaust gas in the intermediate temperature range R with the high temperature heat pipe 81 by the vaporization control means 83 that decompresses the inside of the high temperature heat pipe 81. Can do.

The exhaust heat recovery device 90 having a different vaporization suppression means from the first embodiment will be described in detail with reference to FIGS. 9 and 10.
9 shows a longitudinal sectional view in the vicinity of the heat pipe in the third embodiment, and FIG. 10 shows a block diagram of the exhaust heat recovery apparatus 90 in the third embodiment.

9, the left side in the figure is the combustion chamber C side, the right side in the figure is the catalyst 52 side, the arrow X in the figure is the exhaust gas flow direction, and the arrow Y is the supercritical water or subcritical water flow direction. And
The same configurations as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIGS. 9 and 10, the exhaust heat recovery apparatus 90 of the third embodiment has a loop-shaped high-temperature heat pipe 91 in which the high-temperature heat exchange medium M <b> 1 is sealed and the low-temperature heat exchange medium M <b> 2 in a sealed manner. The loop-shaped low-temperature heat pipe 92, and the high-temperature heat exchange medium M1 and the vaporization control means 93 for controlling the vaporization of the low-temperature heat exchange medium M2.

  As shown in FIG. 9, the heat pipe 91 for high temperature is disposed in the exhaust manifold water supply passage 47a and the heat dissipating section 91b exposed to supercritical water or subcritical water, as shown in FIG. A steam passage 91c connecting the heat absorbing portion 91a and the heat radiating portion 91b on the downstream side of the exhaust manifold exhaust passage 51a, and a reflux passage portion 91d connecting the heat absorbing portion 91a and the heat radiating portion 91b on the upstream side of the exhaust manifold exhaust passage 51a. It is formed in a substantially rectangular loop shape.

  Further, the high temperature heat pipe 91 is integrally formed with a connecting portion 91e extending upward from the heat radiating portion 91b on the downstream side of the exhaust manifold exhaust passage 51a. The connecting portion 91e is connected to an opening hole 51d of the exhaust manifold 51 that is opened with a predetermined size.

In addition, the high temperature heat pipe 91 is integrally formed with a high temperature side piston portion 94 that communicates with the heat absorption portion 91a and stores the high temperature heat exchange medium M1 upstream of the exhaust manifold exhaust passage 51a.
The high temperature side piston portion 94 has a piston 94a disposed therein so as to constitute a medium space in which the high temperature heat exchange medium M1 is stored and an air space in which air is stored.

  As shown in FIGS. 9 and 10, the low temperature heat pipe 92 has substantially the same structure as the high temperature heat pipe 91, and is disposed downstream of the high temperature heat pipe 91 in the exhaust manifold exhaust passage 51a.

  As shown in FIG. 9, the low-temperature heat pipe 92 includes a heat-absorbing part 92a exposed to exhaust gas, a heat-dissipating part 92b exposed to supercritical water or subcritical water, and an exhaust manifold as in the case of the high-temperature heat pipe 91. The steam passage portion 92c located on the downstream side of the passage 51a and the reflux passage portion 92d located on the upstream side of the exhaust manifold exhaust passage 51a are formed in a substantially rectangular loop shape.

  Further, the low temperature heat pipe 92 is integrally formed with a connecting portion 92e extending upward from the heat radiating portion 92b on the downstream side of the exhaust manifold exhaust passage 51a. This connection part 92e is connected to the opening hole 51e of the exhaust manifold 51 opened by the predetermined magnitude | size.

In addition, the low-temperature heat pipe 92 is integrally formed with a low-temperature-side piston portion 95 that communicates with the heat absorption portion 92a and stores the low-temperature heat exchange medium M2 on the upstream side of the exhaust manifold exhaust passage 51a.
The low temperature side piston portion 95 has a piston 95a disposed therein so as to constitute a medium space in which the low temperature heat exchange medium M2 is stored and an air space in which air is stored.

  As shown in FIGS. 9 and 10, the vaporization control means 93 adjusts the internal pressure of the medium reducing unit 96 for reducing the medium amount of the high temperature heat exchange medium M1 stored in the heat absorbing unit 91a and the high temperature heat pipe 91. A high temperature side internal pressure adjusting valve 97, a medium increasing unit 98 for adjusting the medium amount of the low temperature heat exchange medium M2 stored in the heat absorbing unit 92a, and a low temperature side internal pressure adjusting valve 99 for adjusting the internal pressure of the low temperature heat pipe 92. And an exhaust gas temperature sensor 54 and an ECU 2 for controlling these operations.

As shown in FIGS. 9 and 10, the medium weight reducing unit 96 forms a piston type pump with a high temperature side piston portion 94 of the high temperature heat pipe 91 and a pump portion 96 a connected to the high temperature side piston portion 94. It is configured.
The pump part 96 a has a function of pumping compressed air to the air space of the high temperature side piston part 94 and a function of extracting air from the air space of the high temperature side piston part 94.

  As shown in FIGS. 9 and 10, the high temperature side internal pressure adjusting valve 97 is mounted in the opening hole 51 d of the exhaust manifold 51 so as to contact the connection portion 91 e of the high temperature heat pipe 91. The high temperature side internal pressure regulating valve 97 is connected so as to be able to communicate with the pump unit 96a through a pipe (not shown).

  Further, the high temperature side internal pressure regulating valve 97 is electrically connected to the ECU 2 and is controlled by the ECU 2 to an open state in which the on-off valve 97a is opened and a closed state in which the on-off valve 97a is closed. In the high temperature side internal pressure adjusting valve 97, it is assumed that the on-off valve 97a is controlled to be closed immediately after the engine is started.

As shown in FIGS. 9 and 10, the medium increasing unit 98 forms a piston type pump with a low temperature side piston portion 95 of the low temperature heat pipe 92 and a pump portion 98 a connected to the low temperature side piston portion 95. It is configured.
The pump part 98 a has a function of pumping compressed air to the air space of the low temperature side piston part 95 and a function of extracting air from the air space of the low temperature side piston part 95.

  As shown in FIGS. 9 and 10, the low temperature side internal pressure adjusting valve 99 is mounted in the opening hole 51 e of the exhaust manifold 51 so as to contact the connection portion 92 e of the low temperature heat pipe 92. The low temperature side internal pressure adjusting valve 99 is connected to the pump unit 98a through a pipe not shown.

  Further, the low temperature side internal pressure regulating valve 99 is electrically connected to the ECU 2 and is controlled by the ECU 2 to an open state in which the on-off valve 99a is opened and a closed state in which the on-off valve 99a is closed. The low temperature side internal pressure adjusting valve 99 is assumed to have the on-off valve 99a controlled to be closed immediately after the engine is started.

Next, the operation of the vaporization control means 93 in the exhaust heat recovery apparatus 90 will be described.
The operation of the vaporization control means 93 in the exhaust heat recovery apparatus 90 is different from the operation of the vaporization control means 73 in the first embodiment described above in steps S103 and S106 in FIG. Therefore, here, step S103 in FIG. 6 is replaced with “medium amount adjustment start”, and step S106 is replaced with “medium amount restoration”.

  First, in step S102 of FIG. 6, when the acquired exhaust gas temperature is in the intermediate temperature range R (step S102: Yes), the vaporization control means 93 uses the medium amount of the high-temperature heat exchange medium M1 stored in the heat absorption unit 91a. Is started, and the increase of the medium amount of the low-temperature heat exchange medium M2 stored in the heat absorption part 92a is started (step S103).

  Specifically, the vaporization control means 93 starts extraction of air from the high temperature side piston unit 94 when the ECU 2 operates the pump unit 96a of the medium reducing unit 96. And by extracting air, the air space in the high temperature side piston part 94 becomes small, so that the high temperature side piston part 94 reduces the medium amount of the high temperature heat exchange medium M1 in the heat absorbing part 91a.

  At this time, the vaporization control means 93 causes the ECU 2 to open the high temperature side internal pressure adjusting valve 97 to open the high temperature side internal pressure adjusting valve 97 to cause the air extracted by the pump portion 96 a to enter the high temperature heat pipe 91. To supply. Thereby, the vaporization control means 93 reduces the medium amount of the high temperature heat exchange medium M1 in the heat absorption part 91a while maintaining the internal pressure of the high temperature heat pipe 91 substantially constant.

  Further, the vaporization control means 93 starts the pumping of the compressed air to the low temperature side piston unit 95 when the ECU 2 operates the pump unit 98a of the medium increasing unit 98. Then, the piston 95a starts to press the low-temperature heat exchange medium M2 by the compressed air, so that the low-temperature side piston unit 95 increases the medium amount of the low-temperature heat exchange medium M2 in the heat absorption part 92a.

  At this time, the vaporization control means 93 causes the ECU 2 to open the low temperature side internal pressure adjustment valve 99 so that the air supplied to the low temperature side piston portion 95 is supplied to the pump portion 98a via the low temperature side internal pressure adjustment valve 99. Obtained from the heat pipe 92 for low temperature. As a result, the vaporization control means 93 increases the medium amount of the low-temperature heat exchange medium M2 in the heat absorbing section 92a while maintaining the internal pressure of the low-temperature heat pipe 92 substantially constant.

  When the medium amount of the high temperature heat exchange medium M1 and the medium amount of the low temperature heat exchange medium M2 are adjusted to the desired medium amount, the ECU 2 adjusts the high temperature side internal pressure adjustment valve 97 and the low temperature side internal pressure adjustment. The valve 99 is closed.

  As described above, the exhaust heat recovery apparatus 90 can reduce the amount of the high-temperature heat exchange medium M1 and increase the amount of the low-temperature heat exchange medium M2, so that the exhaust heat recovery device 90 can The operating temperature range of the exchange medium M1 and the operating temperature range of the low temperature heat exchange medium M2 are changed.

Thereafter, in step S105, when the acquired exhaust temperature is not within the intermediate temperature range R (step S105: No), the vaporization control means 93 determines the medium amount of the high temperature heat exchange medium M1 and the medium of the low temperature heat exchange medium M2. The amount is returned to the original medium amount (step S106).
Specifically, the vaporization control means 93 is configured such that the ECU 2 opens the high temperature side internal pressure adjustment valve 97 and operates the pump unit 96a of the medium weight reducing unit 96 so that the compressed air is supplied to the high temperature side piston unit 94. Start pumping. Then, the piston 94a starts to press the high-temperature heat exchange medium M1 by pumping the compressed air, so that the high-temperature-side piston section 94 changes the medium amount of the high-temperature heat exchange medium M1 in the heat absorption section 91a to the original medium amount. Increase to.

  Further, the vaporization control means 93 starts the extraction of air from the low temperature side piston portion 95 by the ECU 2 opening the low temperature side internal pressure adjusting valve 99 and operating the pump portion 98a of the medium increasing portion 98. Then, when the piston 95a returns to the original position by the decompression of the air space in the low temperature side piston portion 95, the low temperature side piston portion 95 uses the medium amount of the low temperature heat exchange medium M2 in the heat absorbing portion 92a as the original medium. Reduce the amount.

  When the medium amount of the high temperature heat exchange medium M1 and the medium amount of the low temperature heat exchange medium M2 are returned to the original medium amount, the ECU 2 sets the high temperature side internal pressure adjustment valve 97 and the low temperature side internal pressure adjustment valve 99. Is closed.

  As a result, the exhaust heat recovery apparatus 90 is configured so that the high-temperature heat exchange medium as shown in FIG. 5 like the heat transport characteristic curve TH1 of the high-temperature heat exchange medium M1 and the heat transport characteristic curve TL1 of the low-temperature heat exchange medium M2. The operating temperature range of M1 and the operating temperature range of the low-temperature heat exchange medium M2 are restored.

  The exhaust heat recovery device 90 of the engine 10 that realizes the above-described operation can cope with a wide exhaust temperature range by suppressing an increase in the number of heat pipes as in the first embodiment.

  Further, the medium increasing unit 98 for increasing the amount of the low temperature heat exchange medium M2 stored in the heat absorbing unit 92a, the low temperature side internal pressure adjusting valve 99, the exhaust temperature sensor 54, and the ECU 2 vaporize the low temperature heat exchange medium M2. The exhaust heat recovery device 90 of the engine 10 can reliably recover the heat of the exhaust gas in the intermediate temperature range R with the low-temperature heat pipe 92.

  Specifically, by increasing the medium amount of the low-temperature heat exchange medium M2, the exhaust heat recovery device 90 of the engine 10 converts the heat energy necessary for vaporizing the low-temperature heat exchange medium M2 into the medium amount. The amount can be increased compared to the case where the amount is not increased.

Thereby, when the heat pipe 92 for low temperature is not transporting heat, the exhaust heat recovery device 90 of the engine 10 increases the temperature at which the heat pipe 92 for low temperature starts heat transport and the temperature at which heat transport is stopped. Can do.
Alternatively, when the low-temperature heat pipe 92 is in heat transport, the exhaust heat recovery device 90 of the engine 10 can reduce the vaporization rate of the low-temperature heat exchange medium M2, so that the low-temperature heat pipe is increased by increasing the exhaust temperature. The temperature at which the heat transport of 92 stops can be raised.

  For this reason, the exhaust heat recovery device 90 of the engine 10 sets the operating temperature range of the low temperature heat pipe 92 to the high temperature side by the vaporization control means 93 that increases the medium amount of the low temperature heat exchange medium M2 stored in the heat absorbing portion 92a. The operating temperature range of the low temperature heat pipe 92 can be expanded to the high temperature side.

  Therefore, the exhaust heat recovery apparatus 90 of the engine 10 uses the low-temperature heat exchange medium M2 stored in the heat absorption part 92a to increase the medium amount of the exhaust gas in the intermediate temperature range R for low temperature use. The heat pipe 92 can be reliably recovered.

  Further, vaporization of the high-temperature heat exchange medium M1 is performed by the medium weight reduction unit 96 that reduces the medium amount of the high-temperature heat exchange medium M1 stored in the heat absorption unit 91a, the high-temperature side internal pressure adjustment valve 97, the exhaust temperature sensor 54, and the ECU2. The exhaust heat recovery device 90 of the engine 10 can reliably recover the heat of the exhaust gas in the intermediate temperature range R with the high-temperature heat pipe 91.

  Specifically, by reducing the medium amount of the high-temperature heat exchange medium M1, the exhaust heat recovery device 90 of the engine 10 reduces the heat energy necessary for vaporizing the high-temperature heat exchange medium M1. It can be made smaller compared to the case without it.

Thereby, when the heat pipe 91 for high temperature is not transporting heat, the exhaust heat recovery device 90 of the engine 10 lowers the temperature at which the heat pipe 91 for high temperature starts heat transport and the temperature at which heat transport is stopped. Can do.
Alternatively, when the high-temperature heat pipe 91 is in heat transport, the exhaust heat recovery device 90 of the engine 10 can lower the temperature at which the heat transport of the high-temperature heat pipe 91 stops due to a decrease in the exhaust temperature.

  For this reason, the exhaust heat recovery device 90 of the engine 10 reduces the operating temperature range of the high temperature heat pipe 91 to the low temperature side by the vaporization control means 93 that reduces the medium amount of the high temperature heat exchange medium M1 stored in the heat absorbing portion 91a. Or the operating temperature range of the high temperature heat pipe 91 can be expanded to the low temperature side.

  Accordingly, the exhaust heat recovery device 90 of the engine 10 uses the heat of the exhaust gas in the intermediate temperature range R for high temperature by the vaporization control means 93 that reduces the medium amount of the high temperature heat exchange medium M1 stored in the heat absorbing portion 91a. The heat pipe 91 can be reliably collected.

In correspondence between the configuration of the present invention and the above-described embodiment,
The exhaust passage of the present invention corresponds to the exhaust manifold exhaust passage 51a of the embodiment,
Similarly,
The condensing means corresponds to supercritical water or subcritical water flowing down the exhaust manifold water supply passage 47a,
The temperature detection means corresponds to the exhaust temperature sensor 54,
The low temperature fluid medium corresponds to the low temperature heat exchange medium M2,
The high-temperature fluid medium corresponds to the high-temperature heat exchange medium M1,
The intermediate temperature range corresponds to the intermediate temperature range R,
The cooling means corresponds to the cooling unit 77, the exhaust temperature sensor 54, and the ECU 2,
The pressurizing means corresponds to the pressurizing unit 85, the exhaust temperature sensor 54, and the ECU 2,
The increasing means corresponds to the medium increasing unit 98, the low temperature side internal pressure adjusting valve 99, the exhaust temperature sensor 54, and the ECU 2,
The heating means corresponds to the heating unit 76, the exhaust temperature sensor 54, and the ECU 2,
The decompression means corresponds to the decompression unit 84, the exhaust temperature sensor 54, and the ECU 2,
The weight reducing means corresponds to the medium weight reducing unit 96, the high temperature side internal pressure adjusting valve 97, the exhaust temperature sensor 54, and the ECU 2.
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

  For example, in the above-described embodiment, the loop-shaped high-temperature heat pipes 71, 81, 91 and the low-temperature heat pipes 72, 82, 92 are not limited to this, but the exhaust manifold exhaust passage upstream of the catalyst 52 is used. It is good also as a substantially rod-shaped heat pipe for high temperature in which one end was provided in 51a, and a heat pipe for low temperature.

  In this case, the high temperature heat pipe is positioned so that the tip of the high temperature heat pipe is located upstream of the exhaust manifold exhaust passage 51a and the tip of the low temperature heat pipe is located downstream of the tip of the high temperature heat pipe. And arrange a heat pipe for low temperature. Further, the other end protruding to the outside of the exhaust manifold 51 is provided in a water supply pipe 47 through which, for example, supercritical water or subcritical water flows down.

  In the above-described embodiment, pure water having an operating temperature range of 30 ° C. to 250 ° C. is used as the low-temperature heat exchange medium M2, but this is not a limitation, and naphthalene having an operating temperature range of 150 ° C. to 400 ° C. is a low temperature. It may be a heat exchange medium for use.

  Further, in the above-described embodiment, the exhaust manifold exhaust passage 51a of the exhaust manifold 51 has the heat absorbing portions 71a, 81a, 91a of the high temperature heat pipes 71, 81, 91 and the heat absorbing portions 72a, 82a of the low temperature heat pipes 72, 82, 92. , 92a are provided, but the present invention is not limited to this, and may be disposed at an appropriate location as long as it is on the exhaust passage including the exhaust port 16.

  Further, although the high temperature heat pipes 71, 81, 91 and the low temperature heat pipes 72, 82, 92 are disposed adjacent to each other, the present invention is not limited to this, and the heat pipes 71, 81, 91 are disposed at positions spaced apart by a predetermined distance on the exhaust passage. May be. For example, a high temperature heat pipe may be disposed in the exhaust passage upstream of the catalyst 52, and a low temperature heat pipe may be disposed in the exhaust passage downstream of the catalyst 52.

  In the embodiment described above, the high-temperature heat exchange medium M1 and the low-temperature heat exchange medium M2 in the gas phase are condensed with supercritical water or subcritical water flowing down the exhaust manifold water supply passage 47a. Without limitation, for example, the heat exchange medium in a gas phase may be condensed by a cooling means for electrically cooling the heat exchange medium. Or it is good also as a structure which cools the thermal radiation part of the heat pipe which provided the heat absorption part in the exhaust port 16 with the cooling water which flows down the water jacket of the cylinder head 12, and condenses the heat exchange medium in a gaseous state.

  In the above-described embodiment, the temperature range between the lower limit temperature of the operating temperature range in the high temperature heat pipes 71, 81, 91 and the upper limit temperature of the operating temperature range in the low temperature heat pipes 72, 82, 92 is: Although the intermediate temperature range R is a range expanded by a predetermined temperature on the low temperature side and the high temperature side, the present invention is not limited to this, as shown in FIG. 11 showing an explanatory diagram for explaining the intermediate temperature range R in another embodiment, The intermediate temperature range R may be a temperature range between the lower limit temperature of the operating temperature range of the high temperature heat pipes 71, 81, 91 and the upper limit temperature of the operating temperature range of the low temperature heat pipes 72, 82, 92.

  In this case, when the exhaust temperature rising from the low temperature range reaches the intermediate temperature range R, the heat transport of the low temperature heat pipe 72 is stopped. However, the exhaust heat recovery device 70 of the engine 10 can resume the heat transport of the low-temperature heat pipe 72 in the intermediate temperature range R by the vaporization control means that suppresses the vaporization of the low-temperature heat exchange medium M2.

  Alternatively, when the exhaust temperature lowered from the high temperature range reaches the intermediate temperature range R, the heat transport of the high temperature heat pipe 71 is stopped. However, the exhaust heat recovery device 70 of the engine 10 can restart the heat transport of the high-temperature heat pipe 71 in the intermediate temperature range R by the vaporization control means that promotes vaporization of the high-temperature heat exchange medium M1.

Further, in the above-described embodiment, when the exhaust temperature is in the intermediate temperature range R, the vaporization control means 73, 83, which simultaneously perform the vaporization promotion of the high temperature heat exchange medium M1 and the vaporization suppression of the low temperature heat exchange medium M2. However, the present invention is not limited to this, and when the exhaust temperature is within the intermediate temperature range R, vaporization control for either promoting the vaporization of the high-temperature heat exchange medium M1 or suppressing the vaporization of the low-temperature heat exchange medium M2. It may be a means.
Or it is good also as a vaporization control means which performs vaporization promotion of the heat exchange medium M1 for high temperature, and vaporization suppression of the heat exchange medium M2 for low temperature in order according to a raise of exhaust gas temperature or a fall of exhaust gas temperature.

  In the first embodiment, the high-temperature heat pipe 71 and the low-temperature heat pipe 72 provided with the reservoir tanks 74 and 75 are used. However, the present invention is not limited to this, and the reservoir tank is not required as in the second embodiment. May be. In this case, the heat absorption parts 71 a and 72 a are cooled by the vaporization control means 73.

  Further, in the above-described second embodiment, the high-temperature heat pipe 81 and the low-temperature heat pipe 82 that are not provided with the reservoir tank are used. However, the present invention is not limited thereto, and similarly to the first embodiment, the high-temperature heat pipe provided with the reservoir tank is provided. It is good also as a heat pipe for low temperature and a heat pipe for low temperature.

  Further, in Example 2, the pressurizing unit 85 is configured by the pressurizing electromagnetic valve 87 and the decompression unit 84 is configured by the depressurizing electromagnetic valve 86. However, the present invention is not limited thereto, and the high temperature heat pipe 81 and the low temperature unit As long as the internal pressure of the heat pipe 82 can be adjusted, for example, a rotary electric pump or a pressurizing unit and a depressurizing unit of a piston pump as in the third embodiment may be used.

In the third embodiment described above, the medium reducing unit 96 and the medium increasing unit 98 of the piston pump are used. However, the present invention is not limited to this, and a rotary electric pump or the like may be used.
In Example 3, the vaporization control means 93 includes the high temperature side internal pressure adjustment valve 97 that adjusts the internal pressure of the high temperature heat pipe 91 and the low temperature side internal pressure adjustment valve 99 that adjusts the internal pressure of the low temperature heat pipe 92. However, the present invention is not limited to this, and vaporization control means that does not require the high temperature side internal pressure adjustment valve 97 and the low temperature side internal pressure adjustment valve 99 may be used.

  In this case, in the high-temperature heat pipe 91, the high-temperature heat pipe 91 can be depressurized simultaneously with the reduction of the medium amount. Similarly, in the low-temperature heat pipe 92, the low-temperature heat pipe 92 can be pressurized simultaneously with the increase of the medium amount. Thereby, the exhaust heat recovery device 90 of the engine can perform the vaporization promotion of the high temperature heat exchange medium M1 and the vaporization suppression of the low temperature heat exchange medium M2 more reliably.

2 ... ECU
DESCRIPTION OF SYMBOLS 10 ... Engine 51a ... Exhaust manifold exhaust passage 54 ... Exhaust temperature sensor 70,80,90 ... Exhaust heat recovery apparatus 71,81,91 ... High temperature heat pipe 72,82,92 ... Low temperature heat pipe 73,83,93 ... Vaporization Control means 76 ... heating unit 77 ... cooling unit 84 ... decompression unit 85 ... pressurizing unit 96 ... medium reducing unit 97 ... high temperature side internal pressure adjusting valve 98 ... medium increasing unit 99 ... low temperature side internal pressure adjusting valve C ... combustion chamber M1 ... high temperature Heat exchange medium M2 ... low temperature heat exchange medium R ... intermediate temperature range

Claims (5)

An exhaust heat recovery device for an engine that transports heat of exhaust gas discharged from an engine combustion chamber through a heat pipe in which a fluid medium is sealed,
Two heat pipes partially provided in the exhaust passage through which the exhaust gas flows;
Condensing means for condensing the fluid medium in a gas phase;
Temperature detecting means for detecting an exhaust temperature which is the temperature of the exhaust gas;
Vaporization control means for controlling vaporization of the fluid medium,
The two heat pipes are
A low-temperature heat pipe sealed with a low-temperature fluid medium corresponding to the exhaust temperature in a low-temperature region;
A high-temperature heat pipe sealed with a high-temperature fluid medium corresponding to the exhaust temperature in the high-temperature region,
An exhaust temperature range including an upper limit temperature at which the low temperature heat pipe can be thermally transported and a lower limit temperature at which the high temperature heat pipe can be thermally transported is defined as an intermediate temperature range,
The vaporization control means is
An exhaust heat recovery apparatus for an engine configured to suppress vaporization of the low-temperature fluid medium and / or promote vaporization of the high-temperature fluid medium when the exhaust temperature is in the intermediate temperature range. The intermediate temperature range,
The range of the exhaust temperature between the upper limit temperature at which the heat pipe for low temperature can be transported by heat and the lower limit temperature at which the heat pipe for high temperature can be transported by heat is expanded by a predetermined temperature on the low temperature side and the high temperature side, and The exhaust heat recovery device for an engine according to claim 1. The vaporization control means for suppressing vaporization of the low-temperature fluid medium,
Comprised of cooling means for cooling the cryogenic fluid medium in liquid phase;
Or constituted by a pressurizing means for pressurizing the inside of the low-temperature heat pipe,
The engine exhaust heat recovery apparatus according to claim 1, further comprising an increasing unit configured to increase a medium amount of the low-temperature fluid medium in the low-temperature heat pipe. The vaporization control means for promoting vaporization of the hot fluid medium;
Consist of heating means for heating the high-temperature fluid medium in a liquid phase state,
Or constituted by a decompression means for decompressing the inside of the high-temperature heat pipe,
4. The engine exhaust heat recovery apparatus according to claim 1, further comprising a weight reducing unit configured to reduce a medium amount of the high-temperature fluid medium in the high-temperature heat pipe. In the exhaust passage, the heat pipe for low temperature is
The exhaust heat recovery device for an engine according to any one of claims 1 to 4, wherein the exhaust heat recovery device is disposed downstream of the high-temperature heat pipe.

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