JP2013044239A - Exhaust heat recovery system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust heat recovery system for a vehicle, which can prevent a cooling capacity from becoming insufficient, even when a cooling load of an air conditioner becomes high.SOLUTION: A detection value of a temperature sensor 31 increases when the cooling load of the air conditioner becomes high during a vehicle running motion. When the detection value of the temperature sensor 31 reaches a threshold prestored in a storage unit 30a or above, an ECU 30 switches a three-way valve 24 so that cooling water circulated through a cooling water circulation channel 21 can be circulated through a bypass channel 23. This restrains exhaust heat of an engine 20 from being input into a Rankine cycle 1. Consequently, since the temperature of a coolant flowing into a first capacitor 5 becomes low, the degree of cooling in the first capacitor is decreased, and air as the coolant mainly comes to cool the coolant circulated through a refrigerating cycle 10 in a second capacitor 12.

Description

  The present invention relates to a vehicle exhaust heat recovery apparatus, and more particularly to a vehicle exhaust heat recovery apparatus using a Rankine cycle.

Due to the social demand to reduce carbon dioxide (CO ₂ ) emissions, vehicles with engines such as automobiles are required to improve fuel efficiency, and in order to effectively use energy generated from vehicles that were simply emitted in the past. Technology has been developed. Among them, there is an exhaust heat recovery device using a Rankine cycle that converts heat discharged from an engine such as heat of cooling water and heat of exhaust gas into power of a generator or the like. The Rankine cycle consists of a boiler that generates a superheated steam by heating a liquid fluid that is a working fluid at an equal pressure, an expander that obtains power by adiabatically expanding the superheated steam, and a steam that is expanded in the expander. The condenser is configured to be liquefied by pressure cooling and a pump for sending the liquefied liquid phase fluid to the boiler.

  Patent Document 1 describes such a conventional exhaust heat recovery device that includes a Rankine cycle and a refrigerating cycle for an air conditioner. In this exhaust heat recovery device, an air-cooled condenser is provided in both the Rankine cycle and the refrigeration cycle, but the Rankine cycle condenser is arranged adjacent to the front of the condenser of the refrigeration cycle in the air blowing direction. Yes.

JP 2010-38108 A

  As in the exhaust heat recovery device described in Patent Document 1, when the Rankine cycle condenser is disposed adjacent to the front of the condenser of the refrigeration cycle with respect to the blowing direction, or both capacitors are integrated. In this case, when the Rankine cycle is in operation, the heat dissipation of the condenser of the refrigeration cycle is hindered. In particular, when the cooling load of the air conditioner is large, the cooling capacity of the refrigeration cycle is insufficient.

  The present invention has been made to solve such a problem. When the Rankine cycle capacitor is disposed adjacent to the front of the refrigeration cycle capacitor in the air blowing direction, or both capacitors are integrated. It is an object of the present invention to provide a vehicle exhaust heat recovery device that can prevent a lack of cooling capacity even when the cooling load of an air conditioner increases.

  A vehicle exhaust heat recovery apparatus according to the present invention includes a heat exchanger that heats a first working fluid by an exhaust heat medium of a vehicle engine, and mechanical energy by expanding the first working fluid heated by the heat exchanger. A first condenser that cools the first working fluid discharged from the expander through a heat radiating member with a cooling medium, and a pump that sends the first working fluid cooled by the first condenser to the heat exchanger And a compressor that compresses the second working fluid, a second condenser that cools the second working fluid compressed by the compressor with a cooling medium through the heat dissipation member, and a second condenser that is cooled by the second condenser. A refrigeration cycle for a vehicle air conditioner having a decompression device for decompressing the second working fluid and an evaporator for heating the second working fluid decompressed by the decompression device, and a cooling for detecting a cooling load of the air conditioner. An exhaust heat recovery apparatus for a vehicle including a load detection unit, wherein the first capacitor and the second capacitor share the respective heat dissipating members, or the first capacitor is the second capacitor with respect to the flow of the cooling medium. Is disposed in front of the vehicle, and the vehicle exhaust heat recovery device reduces the amount of heat transfer from the exhaust heat medium to the Rankine cycle when the detection value by the cooling load detection means exceeds a preset threshold value. Control means is further provided. By reducing the amount of heat transfer from the exhaust heat medium to the Rankine cycle, the cooling degree of the first condenser by the cooling medium is reduced, and the cooling medium can cool the second working fluid mainly by the second condenser. .

The heat transfer amount control means includes a waste heat medium main passage for allowing the exhaust heat medium to flow into the heat exchanger, a waste heat medium bypass passage for allowing the waste heat medium to bypass the heat exchanger, and a waste heat medium main flow. An exhaust heat medium flow control means for controlling the flow of the exhaust heat medium in the passage and the exhaust heat medium bypass flow path may be provided. The exhaust heat medium flow control means may be an exhaust heat medium flow switching device that switches so that the exhaust heat medium flows through either the exhaust heat medium main flow path or the exhaust heat medium bypass flow path.
The heat transfer amount control means includes a first working fluid main channel for allowing the first working fluid to flow into the heat exchanger, a first working fluid bypass channel for allowing the first working fluid to bypass the heat exchanger, You may provide the 1st working fluid flow control means which controls the flow of the 1st working fluid in the 1st working fluid main channel and the 1st working fluid bypass channel. The first working fluid flow control means may be a first working fluid flow switching device that switches so that the first working fluid flows through one of the first working fluid main flow path and the first working fluid bypass flow path.
The heat transfer amount control means may be a first working fluid circulation flow rate control device that controls a flow rate of the first working fluid circulating through the Rankine cycle.
The cooling load detection means may be a temperature sensor that detects the temperature of the second working fluid that has flowed out of the evaporator.
The first capacitor and the second capacitor share the respective heat dissipating members, and the output request value detection means for detecting the engine output request value and the detection value by the output request value detection means are equal to or greater than a preset threshold value. Then, a second working fluid circulation flow rate control device that controls a flow rate of the second working fluid circulating in the refrigeration cycle may be provided. The requested output value may be an accelerator opening provided in the vehicle, and the requested output value detecting means may be an accelerator opening sensor that detects the opening.

  According to this invention, the Rankine cycle and the refrigeration cycle for the air conditioner are provided, and the first condenser of the Rankine cycle and the second condenser of the refrigeration cycle share the respective heat dissipating members or with respect to the flow of the cooling medium. In the vehicle exhaust heat recovery device in which the first capacitor is disposed in front of the second capacitor, when the cooling load of the air conditioner increases, the amount of heat transfer from the exhaust heat medium to the Rankine cycle is reduced, thereby cooling the vehicle. Since the cooling degree of the first condenser by the medium decreases and the cooling medium can cool the second working fluid mainly by the second condenser, the cooling capacity is insufficient even when the demand for the cooling capacity of the air conditioner increases. Can be prevented.

1 is a configuration diagram of a vehicle exhaust heat recovery device according to Embodiment 1 of the present invention. FIG. It is sectional drawing along the II-II line of FIG. It is the elements on larger scale seen in the direction of the arrow A of FIG. FIG. 4 is a configuration diagram of a vehicle exhaust heat recovery device according to a second embodiment. It is sectional drawing along the VV line of FIG. FIG. 6 is a configuration diagram of a vehicle exhaust heat recovery device according to a third embodiment. FIG. 6 is a configuration diagram of a vehicle exhaust heat recovery device according to a fourth embodiment.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
Embodiment 1 FIG.
As shown in FIG. 1, the vehicle exhaust heat recovery apparatus according to Embodiment 1 includes a Rankine cycle 1 and a refrigeration cycle 10 for a vehicle air conditioner.
Rankine cycle 1 includes a pump 2, a boiler 3 that is a heat exchanger, an expander 4, an air-cooled first condenser 5, and a refrigerant in which a refrigerant that is a first working fluid circulates in an annular manner. And a circulation channel 6. The refrigeration cycle 10 includes a compressor 11, an air-cooled second condenser 12, an expansion valve 13 that is a decompression device, an evaporator 14, and a refrigerant that is a second working fluid that circulates in an annular manner. And a refrigerant circulation channel 16. Here, the refrigerant circulating through the Rankine cycle 1 and the refrigeration cycle 10 is an arbitrary refrigerant, and may be the same refrigerant or different refrigerants.

  The vehicle engine 20 has a cooling water circulation passage 21 through which cooling water circulates. The cooling water circulation channel 21 includes a main channel 22 that allows cooling water to flow into the boiler 3 in order to exchange heat with the refrigerant circulating in the Rankine cycle 1, and a bypass channel 23 that bypasses the cooling water without flowing into the boiler 3. And a three-way valve 24 for switching the cooling water to one of the main flow path 22 and the bypass flow path 23. Here, the cooling water constitutes an exhaust heat medium for transferring (heat input) the exhaust heat of the engine 20 to the Rankine cycle 1, and the three-way valve 24 constitutes an exhaust heat medium flow switching device, and the main flow path 22. The bypass flow path 23 and the three-way valve 24 constitute heat transfer amount control means for controlling the heat (waste heat) transfer amount to the Rankine cycle 1.

  In the refrigeration cycle 10, a temperature sensor 31 for detecting the temperature of the refrigerant that has flowed out of the evaporator 14 is provided between the evaporator 14 and the compressor 11. If the cooling load of the air conditioner increases under the condition that the cooling capacity of the second condenser 12 does not change, the temperature of the refrigerant flowing out of the evaporator 14 increases. This temperature constitutes the cooling load request value, and the temperature sensor 31. Constitutes a cooling load request value detecting means.

  An accelerator opening sensor 33 that detects the accelerator opening of the accelerator 32 is provided in the accelerator 32 of the vehicle on which the engine 20 is mounted. As the accelerator 32 is stepped on, that is, as the accelerator opening increases, the vehicle output demand increases. Therefore, the accelerator opening constitutes the output demand value of the engine 20, and the accelerator opening sensor 33 provides the output demand value detection means. Configure.

  Each of the temperature sensor 31 and the accelerator opening sensor 33 is electrically connected to an ECU 30 that is a vehicle control device, and each detected value is transmitted to the ECU 30. The ECU 30 incorporates a storage unit 30a that stores in advance a threshold value for the temperature of the refrigerant flowing out of the evaporator 14 and a threshold value for the accelerator opening of the accelerator 32.

  The ECU 30 is also electrically connected to the compressor 11 and the three-way valve 24 so that the compressor 11 can be driven and stopped and the three-way valve 24 can be switched. When the compressor 11 is stopped, the flow rate of the refrigerant circulating in the refrigeration cycle 10 becomes 0, so the ECU 30 constitutes a second working fluid circulation flow rate control device.

  As shown in FIG. 2, the first capacitor 5 and the second capacitor 12 are composed of a plurality of plate-like integrated refrigerant tubes 40 and radiating fins 50 provided between adjacent integrated refrigerant tubes 40, 40. It is configured. Inside the integrated refrigerant tube 40, a plurality of refrigerant tubes 41 through which the refrigerant circulating in the Rankine cycle 1 (see FIG. 1) flows, and a plurality of refrigerants through which the refrigerant circulating through the refrigeration cycle 10 (see FIG. 1) flows. A tube 42 is formed. The heat radiating fins 50 are formed by bending a metal single plate into a wave shape in the longitudinal direction of the refrigerant tubes 41 and 42 (direction perpendicular to the paper surface of FIG. 2), as shown in FIG. The corrugated peak portions 50a and the valley portions 50b are provided so as to be in contact with the adjacent integrated refrigerant tubes 40, 40, respectively. The integrated refrigerant pipes 40 and 40 adjacent to the heat radiating fin 50 are a plurality of pieces extending in a direction perpendicular to the longitudinal direction of the refrigerant pipes 41 and 42 (see FIG. 2) (in the direction of arrow A in FIG. 2). A cavity 51 is formed, and when air flows through the cavity 51, the heat of the refrigerant flowing through each of the refrigerant pipes 41 and 42 is radiated to the air via the integrated refrigerant pipe 40 and the radiation fins 50. As a result, the refrigerant is cooled. Here, since the heat of the refrigerant is radiated to the air through the integrated refrigerant pipe 40 and the heat radiation fin 50, these constitute a heat radiation member, and the first capacitor 5 and the second capacitor 12 share the heat radiation member. Will be. The air flowing through the cavity 51 constitutes a cooling medium for cooling the refrigerant flowing through each of the refrigerant tubes 41 and 42.

Next, the operation of the vehicle exhaust heat recovery apparatus according to the first embodiment will be described with reference to FIG.
First, the operation when the detected value by the temperature sensor 31 and the detected value by the accelerator opening sensor 33 are smaller than the threshold value stored in advance in the storage unit 30a during the operation of the engine 20 will be described. In this case, the cooling water circulating through the cooling water circulation channel 21 is circulated through the main channel 22 by the three-way valve 24.

  In the Rankine cycle 1, the refrigerant discharged from the pump 2 flows into the boiler 3. The refrigerant flowing into the boiler 3 is heated to gas by exchanging heat with the cooling water flowing through the main flow path 22. Thereby, the exhaust heat of the engine 20 is input to the Rankine cycle 1. The refrigerant gas flowing out from the boiler 3 is sucked into the expander 4 and drives the expander 4. The refrigerant expanded by the expander 4 is cooled and condensed by the first condenser 5 and is again sucked into the pump 2 to circulate through the Rankine cycle 1. A power generator (not shown) is driven by the power generated by the expander 4 to generate power.

  When the vehicle air conditioner is used, the refrigerant gas compressed by the compressor 11 is cooled and condensed by the second condenser 12. The liquid refrigerant flowing out of the second condenser 12 is decompressed by the expansion valve 13 and then heated in the evaporator 14 by heat exchange with the air going into the vehicle to become refrigerant gas, which is again sucked into the compressor 11. As a result, the refrigeration cycle 10 is circulated. The heat-exchanged air is supplied into the vehicle as cold air.

  When the cooling load of the air conditioner increases while the vehicle is traveling, the detection value of the temperature sensor 31 increases. In this case, it is necessary to increase the cooling capacity of the second capacitor 12. However, since the first capacitor 5 and the second capacitor 12 share a heat dissipation member, not only the refrigerant circulating in the refrigeration cycle 10 but also the Rankine cycle. The refrigerant circulating in 1 is also cooled to the same extent. For this reason, when Rankine cycle 1 is operating, cooling in second capacitor 12 becomes insufficient.

  Therefore, when the detected value of the temperature sensor 31 is equal to or greater than the threshold value stored in advance in the storage unit 30a, the ECU 30 switches the three-way valve 24 so that the cooling water circulating in the cooling water circulation passage 21 passes through the bypass passage 23. To circulate. Accordingly, the cooling water does not flow into the boiler 3, so that the refrigerant circulating in the Rankine cycle 1 is not heated by the cooling water in the boiler 3. That is, heat input to the Rankine cycle 1 of the exhaust heat of the engine 20 is suppressed.

  Then, since the temperature of the refrigerant flowing into the first condenser 5 is lowered, the degree of cooling in the first condenser is reduced, and the air that is the cooling medium is mainly the refrigerant that circulates in the refrigeration cycle 10 in the second condenser 12. Will come to cool. Thereby, since the enthalpy of the refrigerant | coolant which flows into the evaporator 14 becomes small, the air_conditioning | cooling capability of an air conditioner rises. Thereafter, when the detected value of the temperature sensor 31 becomes lower than the threshold value, the ECU 30 switches the three-way valve 24 and restarts the Rankine cycle 1. Note that the threshold values stored in advance in the storage unit 30a are the upper threshold value and the lower threshold value. The upper threshold value plays the same role as the above threshold value, and the lower threshold value can be used as a reference for restarting the Rankine cycle 1. Good.

  On the other hand, when the output of the engine 20 increases while the vehicle is running, the amount of exhaust heat of the engine also increases, so the output that the Rankine cycle 1 regenerates also increases. However, since the size of the Rankine cycle 1 is unchanged, the condensation pressure increases and the thermal efficiency of the Rankine cycle 1 decreases. Therefore, the ECU 30 stops the compressor 11 when the value detected by the accelerator opening sensor 33 is equal to or greater than a threshold value stored in advance in the storage unit 30a. Then, the air conditioner of the vehicle is stopped and the degree of cooling in the second condenser 12 is reduced, so that air as a cooling medium mainly cools the refrigerant circulating in the Rankine cycle 1 in the first condenser 5. . Thereby, the fall of the thermal efficiency of Rankine cycle 1 is suppressed. Thereafter, when the value detected by the accelerator opening sensor 33 falls below the threshold value, the ECU 30 activates the compressor 11 again.

  Thus, when the detected value of the temperature sensor 31 is equal to or greater than the threshold value stored in advance in the storage unit 30a, the ECU 30 switches the three-way valve 24 so that the cooling water circulating in the cooling water circulation passage 21 is bypassed by the bypass passage 23. By suppressing the movement of the exhaust heat to the Rankine cycle 1 by circulating the air, the degree of cooling by the first condenser 5 by air is reduced, and the air is mainly fed by the second condenser 12 and the refrigeration cycle 10 is made to flow. Since the circulating refrigerant can be cooled, it is possible to prevent a decrease in the cooling capacity even when the demand for the cooling capacity of the air conditioner increases.

  In the first embodiment, the exhaust heat medium flow switching device is the three-way valve 24 for switching the cooling water to one of the main flow path 22 and the bypass flow path 23, but is not limited to this form. For example, a flow rate adjustment valve may be provided in the bypass flow path 23 to adjust the flow rate of the cooling water flowing through each of the main flow path 22 and the bypass flow path 23. In this case, the heat transfer amount control means includes the main flow path 22, the bypass flow path 23, and the flow rate adjusting valve.

  In the first embodiment, the ECU 30 stops the compressor 11 when the value detected by the accelerator opening sensor 33 is equal to or greater than the threshold value. However, the present invention is not limited to this embodiment. For example, the compressor 11 may be a variable capacity compressor such as a swash plate compressor, and the ECU 30 may change the capacity of the compressor 11. In this case, the flow rate of the refrigerant circulating through the refrigeration cycle 10 does not become zero, but can be adjusted to an arbitrary flow rate.

Embodiment 2. FIG.
Next, a vehicle exhaust heat recovery device according to Embodiment 2 of the present invention will be described. In the following embodiments, the same reference numerals as those in FIGS. 1 to 3 are the same or similar components, and thus detailed description thereof is omitted.
The vehicle exhaust heat recovery apparatus according to the second embodiment of the present invention is different from the first embodiment in that the first capacitor 5 and the second capacitor 12 are separated.

  As shown in FIG. 4, the first capacitor 5 and the second capacitor 12 which are air-cooled capacitors are separate from each other. As shown in FIG. 5, each of the first capacitor 5 and the second capacitor 12 includes a plurality of integrated refrigerant tubes 40 ′ formed only with a plurality of refrigerant tubes 41 and a plurality formed only with a plurality of refrigerant tubes 42. 2 and 3 are shown between the adjacent integrated refrigerant tubes 40 'and 40' and between the adjacent integrated refrigerant tubes 40 "and 40", respectively. In other words, in the second embodiment, the first capacitor 5 and the second capacitor 12 do not share a heat radiating member. The first capacitor 5 is disposed in front of the second capacitor 12.

  As shown in FIG. 4, for other configurations, the compressor 11 is started and stopped based on the point that the accelerator opening sensor 33 is not provided and the detected value by the accelerator opening sensor 33. It is the same as that of Embodiment 1 except that there is no point.

  In the second embodiment, since the first capacitor 5 is arranged in front of the second capacitor 12 with respect to the air flow, the air cools the refrigerant circulating in the Rankine cycle 1 in the first capacitor 5. In the second condenser 12, the refrigerant circulating in the refrigeration cycle 10 is cooled. For this reason, when Rankine cycle 1 is operating, the cooling capacity of the refrigerant in second capacitor 12 is smaller than the cooling capacity of the refrigerant in first capacitor 5.

  If the cooling load of the air conditioner increases while the vehicle is traveling, the detected value of the temperature sensor 31 increases due to the same operation as in the first embodiment. In this case, it is necessary to increase the cooling capacity of the second capacitor 12. However, since the cooling capacity of the refrigerant is smaller in the second capacitor 12 than in the first capacitor 5, if the Rankine cycle 1 is operating, Cooling in the capacitor 12 is insufficient. Therefore, as in the first embodiment, when the detected value of the temperature sensor 31 is equal to or greater than the threshold value, the ECU 30 switches the three-way valve 24 to suppress heat input of the exhaust heat of the engine 20 to the Rankine cycle 1. The air that is the cooling medium mainly cools the refrigerant circulating in the refrigeration cycle 10 in the second condenser 12. Thereby, the temperature of the refrigerant flowing into the evaporator 14 is lowered, and the cooling capacity of the air conditioner is increased, so that the same effect as in the first embodiment can be obtained.

Embodiment 3 FIG.
Next, a vehicle exhaust heat recovery device according to Embodiment 3 of the present invention will be described.
The vehicle exhaust heat recovery device according to Embodiment 3 of the present invention is different from Embodiment 1 in that heat for controlling the amount of heat transferred from the cooling water circulating in the cooling water circulation passage 21 to the Rankine cycle is 1. The form of the movement amount control means is changed.

As shown in FIG. 6, in the Rankine cycle 1, the refrigerant circulation flow path 6 includes a main flow path 62 for allowing the refrigerant to flow into the boiler 3, a bypass flow path 63 for bypassing the refrigerant without flowing into the boiler 3, And a three-way valve 64 for switching the refrigerant to one of the main flow path 62 and the bypass flow path 63. The ECU 30 is electrically connected to the three-way valve 64 so that the three-way valve 64 can be switched. Here, the three-way valve 64 constitutes a first working fluid flow switching device, and the main flow path 62, the bypass flow path 63, and the three-way valve 64 control the amount of heat (exhaust heat) transfer to the Rankine cycle 1. The heat transfer amount control means is configured.
Other configurations are the same as those in the first embodiment except that there is no configuration for the cooling water circulating in the cooling water circulation passage 21 to bypass the boiler 3.

  If the cooling load of the air conditioner increases while the vehicle is traveling, the detected value of the temperature sensor 31 increases due to the same operation as in the first embodiment. When the detected value is equal to or greater than the threshold value stored in advance in the storage unit 30 a, the ECU 30 switches the three-way valve 64 so that the refrigerant flows through the bypass flow path 63. As a result, the refrigerant does not flow into the boiler 3, so that the refrigerant circulating in the Rankine cycle 1 is not heated by the cooling water in the boiler 3. That is, heat input to the Rankine cycle 1 of the exhaust heat of the engine 20 is suppressed. As a result, as in the first embodiment, the air as the cooling medium mainly cools the refrigerant circulating in the refrigeration cycle 10 in the second condenser 12, and the temperature of the refrigerant flowing into the evaporator 14 is reduced. Since it becomes lower, the cooling capacity of the air conditioner increases. Therefore, the same effect as in the first embodiment can be obtained. The operation when the output of the engine 20 increases while the vehicle is running is the same as in the first embodiment.

  In the third embodiment, the first working fluid flow switching device is the three-way valve 64 for switching the refrigerant to one of the main flow path 62 and the bypass flow path 63, but is not limited to this form. For example, a flow rate adjusting valve may be provided in the bypass flow path 63 to adjust the flow rate of the refrigerant flowing through the main flow path 62 and the bypass flow path 63. In this case, the heat transfer amount control means includes the main flow path 62, the bypass flow path 63, and the flow rate adjusting valve.

Embodiment 4 FIG.
Next, a vehicle exhaust heat recovery device according to Embodiment 4 of the present invention will be described.
The vehicle exhaust heat recovery apparatus according to Embodiment 4 of the present invention is different from Embodiment 1 in that heat for controlling the amount of heat transferred from the cooling water circulating in the cooling water circulation passage 21 to the Rankine cycle is 1. The form of the movement amount control means is changed.

  As shown in FIG. 7, the ECU 30 is electrically connected to the pump 2 and can control the rotation speed of the pump 2. When the rotation speed of the pump 2 is changed, the flow rate of the refrigerant circulating in the Rankine cycle 1 is changed, so the ECU 30 constitutes a first working fluid circulation flow rate control device. Other configurations are the same as those in the first embodiment except that there is no configuration for the cooling water circulating in the cooling water circulation passage 21 to bypass the boiler 3.

  If the cooling load of the air conditioner increases while the vehicle is traveling, the detected value of the temperature sensor 31 increases due to the same operation as in the first embodiment. When the detected value is equal to or greater than a threshold value stored in advance in the storage unit 30a, the ECU 30 decreases the rotational speed of the pump 2 and decreases the flow rate of the refrigerant circulating in the Rankine cycle 1. Thereby, since the heat exchange efficiency of the refrigerant | coolant and cooling water in the boiler 3 falls, the heat input amount to the Rankine cycle 1 of the exhaust heat of the engine 20 becomes small. As a result, the cooling degree of the air that is the cooling medium decreases in the first condenser 5 and the cooling degree in the second condenser 12 increases. Then, since the temperature of the refrigerant flowing into the evaporator 14 is lowered, the cooling capacity of the air conditioner is increased. Therefore, the same effect as in the first embodiment can be obtained. The operation when the output of the engine 20 increases while the vehicle is running is the same as in the first embodiment.

  In the fourth embodiment, the ECU 30 can control the rotational speed of the pump 2, but is not limited to this form. The ECU 30 may control the amount of heat transfer from the cooling water circulating in the cooling water circulation passage 21 to the Rankine cycle by on / off control whether the pump 2 is stopped or driven.

  In the first to fourth embodiments, the cooling water is used as the exhaust heat medium for moving the exhaust heat of the engine 20 (see FIG. 1 and the like) to the Rankine cycle 1, but the present invention is not limited to this form. The exhaust gas discharged from the engine 20 can also be used as an exhaust heat medium. In this case, a part of the exhaust pipe through which the exhaust gas flows passes through the boiler 3 (see FIG. 1 and the like).

  1 Rankine cycle, 2 pump, 3 boiler (heat exchanger), 4 expander, 5 first condenser, 10 refrigeration cycle, 11 compressor, 12 second condenser, 13 expansion valve (decompression device), 14 evaporator, 20 Engine, 22 main flow paths (exhaust heat medium main flow path), 23 bypass flow path (exhaust heat medium bypass flow path), 24 three-way valve (exhaust heat medium flow switching device), 30 ECU (first working fluid circulation flow control device, (Second working fluid circulation flow control device), 31 temperature sensor (cooling load detection means), 33 accelerator opening sensor (output required value detection means), 40 integrated refrigerant pipe (heat radiation member), 50 heat radiation fin (heat radiation member) 62 main flow path (first working fluid main flow path), 63 bypass flow path (first working fluid bypass flow path), 64 three-way valve (first working fluid flow switching device).

Claims (9)

A heat exchanger that heats a first working fluid by a waste heat medium of a vehicle engine, an expander that expands the first working fluid heated by the heat exchanger to obtain mechanical energy, and a discharge from the expander A Rankine cycle having a first condenser that cools the first working fluid cooled by a cooling medium through a heat dissipation member, and a pump that sends the first working fluid cooled by the first condenser to the heat exchanger;
A compressor that compresses the second working fluid, a second capacitor that cools the second working fluid compressed by the compressor through the heat dissipation member by the cooling medium, and a second operation that is cooled by the second capacitor A refrigeration cycle for an air conditioner of the vehicle, comprising: a decompression device that decompresses the fluid; and an evaporator that heats the second working fluid decompressed by the decompression device;
A vehicle exhaust heat recovery device comprising cooling load detection means for detecting a cooling load of the air conditioner,
The first capacitor and the second capacitor share the respective heat dissipating members, or the first capacitor is disposed in front of the second capacitor with respect to the flow of the cooling medium,
The vehicle exhaust heat recovery device has a heat transfer amount control means for reducing a heat transfer amount from the exhaust heat medium to the Rankine cycle when a detection value by the cooling load detection means is equal to or greater than a preset threshold value. An exhaust heat recovery device for a vehicle further comprising: The heat transfer amount control means includes
An exhaust heat medium main flow path for allowing the exhaust heat medium to flow into the heat exchanger;
An exhaust heat medium bypass flow path for the exhaust heat medium to bypass the heat exchanger;
The vehicle exhaust heat recovery device according to claim 1, further comprising: an exhaust heat medium flow control unit configured to control a flow of the exhaust heat medium in the exhaust heat medium main flow path and the exhaust heat medium bypass flow path.   The exhaust heat medium flow control means is an exhaust heat medium flow switching device that switches the exhaust heat medium to flow through either the exhaust heat medium main flow path or the exhaust heat medium bypass flow path. The vehicle exhaust heat recovery device as described. The heat transfer amount control means includes
A first working fluid main flow path for the first working fluid to flow into the heat exchanger;
A first working fluid bypass passage for the first working fluid to bypass the heat exchanger;
2. The vehicle exhaust heat recovery device according to claim 1, further comprising: a first working fluid flow control unit configured to control a flow of the first working fluid in the first working fluid main flow path and the first working fluid bypass flow path. .   The first working fluid flow control means is a first working fluid flow switching device that switches so that the first working fluid flows through either the first working fluid main flow path or the first working fluid bypass flow path. The exhaust heat recovery device for a vehicle according to claim 4.   2. The vehicle exhaust heat recovery device according to claim 1, wherein the heat transfer amount control means is a first working fluid circulation flow rate control device that controls a flow rate at which the first working fluid circulates through the Rankine cycle.   The exhaust heat recovery device for a vehicle according to any one of claims 1 to 6, wherein the cooling load detection means is a temperature sensor that detects a temperature of the second working fluid that has flowed out of the evaporator. The first capacitor and the second capacitor share a heat dissipation member,
Output request value detection means for detecting the output request value of the engine;
And a second working fluid circulation flow rate control device for controlling a flow rate at which the second working fluid circulates in the refrigeration cycle when a detected value by the output request value detecting means is equal to or greater than a preset threshold value. Item 8. The vehicle exhaust heat recovery device according to any one of Items 1 to 7.   The vehicle exhaust heat according to claim 8, wherein the output request value is an accelerator opening degree provided in the vehicle, and the output request value detection means is an accelerator opening sensor that detects the opening degree. Recovery device.

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