JP2015200179A - heat exchange system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently cool a working medium of a Rankine cycle.SOLUTION: A heat exchange system 1 is loaded on a hybrid vehicle using power of an engine and a motor. The heat exchange system 1 includes a heat exchanger 21 for recovering waste heat of the engine 10 in a refrigerant, an expander 23 generating power by using the refrigerant at an outlet of the heat exchanger, and a Rankine cycle 20 including a condenser 24 for condensing the refrigerant from the expander 23. The heat exchange system 1 includes a control device 31 for controlling the motor, and a cooling water passage 32 in which cooling water for cooling the control device 31 flows, and the condenser 24 is cooled by the cooling water for cooling the control device 31.

Description

  The present invention relates to a heat exchange system mounted on a hybrid vehicle.

  A system for obtaining power by using waste heat of a vehicle by Rankine cycle has been proposed. In a vehicle having a Rankine cycle and an air conditioner cycle, a Rankine condenser and an air conditioner condenser are usually arranged in the front end portion of the vehicle (see Patent Document 1).

JP 2011-84102 A

  However, in the vehicle having the Rankine cycle described above, it is necessary to provide a Rankine condenser at the front end, so that the installation space for the condenser for the air conditioner is limited. For this reason, the cooling performance of other condensers is reduced, and the working medium of the Rankine cycle is not efficiently cooled.

  The present invention has been made paying attention to such conventional problems. An object of the present invention is to efficiently cool the working medium of the Rankine cycle.

  The present invention solves the above problems by the following means.

  The system according to the present invention is a heat exchange system mounted on a hybrid vehicle using the power of an engine and an electric motor. The heat exchange system includes a heat exchanger that recovers engine waste heat into a refrigerant, an expander that generates power using the refrigerant at the outlet of the heat exchanger, and a Rankine that includes a condenser that condenses the refrigerant that has exited the expander. Have a cycle. The heat exchange system includes a control device that controls the electric motor and a cooling water passage through which cooling water that cools the control device flows, and the condenser is cooled by cooling water that cools the control device.

  According to this aspect, the working medium of the Rankine cycle can be efficiently cooled by the cooling water that cools the control device.

  Embodiments of the present invention and advantages of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a configuration diagram showing a heat exchange system according to the first embodiment of the present invention. FIG. 2 is a diagram showing an arrangement of radiators mounted on the hybrid vehicle. FIG. 3 is a diagram showing the cooling capacity of a condenser sharing a radiator. FIG. 4 is a configuration diagram illustrating a heat exchange system according to the second embodiment. FIG. 5 is a configuration diagram showing a heat exchange system according to the third embodiment. FIG. 6 is a configuration diagram showing a heat exchange system according to the fourth embodiment. FIG. 7 is a configuration diagram illustrating a heat exchange system according to the fifth embodiment. FIG. 8 is a configuration diagram illustrating a heat exchange system according to the sixth embodiment. FIG. 9 is a configuration diagram illustrating a heat exchange system according to the seventh embodiment.

(First embodiment)
FIG. 1 is a diagram showing a heat exchange system according to the first embodiment of the present invention.

  The heat exchange system 1 is mounted on a hybrid vehicle that uses power from an engine and an electric motor. The heat exchange system 1 regenerates the waste heat energy of the engine 10 as power of the engine 10 using the Rankine cycle 20 and cools the inverter 31 using the cooling device 30.

  The heat exchange system 1 includes an engine 10, a cooling water passage 12, a heat exchanger 21, a refrigerant passage 22, a rotating machine 23, a condenser 24, a belt transmission mechanism 25, a cooling device 30, and a radiator 110. And a radiator fan 111. The rotating machine 23 includes an expander 231 and a refrigerant pump 232.

  The Rankine cycle 20 includes a heat exchanger 21 that recovers waste heat of the engine 10 into a refrigerant, an expander 231 that generates power using the refrigerant at the outlet 211 of the heat exchanger 21, and a refrigerant that has exited the expander 231. Condensing condenser 24 is included. The heat exchange system 1 uses the heat exchanger 21 to recover the waste heat of the engine 10 into the refrigerant of the Rankine cycle 20, and drives the expander 231 by expansion of the refrigerant. The driving force of the expander 231 is used as power for rotating the refrigerant pump 232 and is also used as power for assisting the engine 10 via the belt transmission mechanism 25. The refrigerant of Rankine cycle 20 is a working medium that operates expander 231.

  The heat exchanger 21 has a cooling water passage of the engine 10 and a refrigerant passage of the Rankine cycle 20. A cooling water passage 12 and a refrigerant passage 22 are connected to each passage of the heat exchanger 21. The heat exchanger 21 causes cooling water to flow around the refrigerant passage to exchange heat between the refrigerant and the cooling water, and evaporates the refrigerant by the waste heat of the engine 10.

  The engine 10 is a power source that drives the vehicle. The engine 10 burns gasoline and converts the combustion energy into the rotational force of the crankshaft 101.

  The radiator fan 111 sends wind to the radiator 110 to cool the radiator 110.

  The radiator 110 cools the cooling water by the wind power of the radiator fan 111.

  The cooling water passage 12 includes a forward passage connecting the radiator 110 and the engine 10, a return passage connecting the engine 10 and the radiator 110, a branch passage branched from the return passage and connected to the inlet of the heat exchanger 21, and the heat exchanger 21. And a merging passage that merges from the exit to the outward path.

  In the cooling water passage 12, the cooling water cooled by the radiator 110 circulates. When the cooling water passes through the engine 10, the temperature of the cooling water rises to about 80 ° C to 90 ° C. As the temperature-increased cooling water passes through the heat exchanger 21, the refrigerant in the Rankine cycle 20 is vaporized and flows out from the heat exchanger 21 to the refrigerant passage 22.

  The refrigerant passage 22 includes a passage connecting the heat exchanger 21 and the expander 231, a passage connecting the expander 231 and the condenser 24, a passage connecting the condenser 24 and the refrigerant pump 232, and the refrigerant pump 232 and heat. And a passage connecting to the exchanger 21.

  The refrigerant passage 22 includes a bypass passage that joins from the passage connecting the heat exchanger 21 and the expander 231 to the passage connecting the expander 231 and the condenser 24. A bypass valve 26 is provided in the bypass passage. The bypass valve 26 opens when the amount of refrigerant flowing through the refrigerant passage 22 is not sufficient, for example, when the Rankine cycle 20 is started. Thereby, the starting time of Rankine cycle 20 is shortened. In the present embodiment, for convenience of explanation, a temperature sensor, a pressure sensor, and the like provided in the refrigerant passage 22 are omitted.

  The expander 231 rotates the rotating shaft of the refrigerant pump 232 by expanding the refrigerant vaporized by the heat exchanger 21. As a result, the pulley 251 of the belt transmission mechanism 25 rotates to assist the engine 10. That is, the expander 231 generates a force that assists the engine 10 by expansion and contraction of the refrigerant. The expander 231 is a steam turbine.

  The condenser 24 cools and liquefies the refrigerant expanded by the expander 231. The refrigerant liquefied by the condenser 24 flows to the refrigerant pump 232.

  The refrigerant pump 232 is rotated by the driving force of the expander 231 and supplies the refrigerant liquefied by the condenser 24 to the refrigerant passage of the heat exchanger 21. The rotation axis of the refrigerant pump 232 is coaxial with the expander 231 and the pulley 251. A clutch is provided between the rotation shafts of the refrigerant pump 232 and the pulley 251. When the clutch is in the disconnected state, the refrigerant pump 232 rotates together with the belt transmission mechanism 25 by the driving force of the expander 231.

  In the Rankine cycle 20, the refrigerant flowing through the refrigerant passage 22 is vaporized by the heat of the cooling water heated by the waste heat of the engine 10 when passing through the heat exchanger 21. When the evaporated refrigerant enters the expander 231, the expander 231 expands the refrigerant and converts it into rotational energy. As the expander 231 rotates, the pulley 252 of the belt transmission mechanism 25 is driven to assist the rotation of the crankshaft 101.

  In such Rankine cycle, since a radiator is generally used for the condenser, the Rankine cycle radiator is arranged so as to overlap with the engine radiator or the like. Here, the arrangement of the radiators mounted on the hybrid vehicle will be briefly described.

  FIG. 2 is a diagram showing a general radiator arrangement. FIG. 2A is a side view of the radiator mounted on the front end of the vehicle. FIG. 2B is a diagram showing the arrangement of the radiators when the radiators are used in the Rankine cycle condenser. 2A and 2B, the flow of wind from the radiator fan 111 is indicated by a solid line.

  As shown in FIG. 2A, the radiator 110 of the engine 10, the radiator 120 of the air conditioner, and the radiator 130 of the inverter 31 are arranged so as to overlap in the direction in which the wind of the radiator fan 111 flows.

  And in the vehicle using Rankine cycle 20, as shown in Drawing 2 (B), the radiator used for condenser 24 will be piled up and arranged on other radiators. For this reason, as the number of radiators increases, the cooling performance of each radiator decreases.

  Accordingly, in the present invention, the Rankine cycle refrigerant is efficiently cooled using the radiator of the inverter.

  In the present embodiment, the condenser 24 shown in FIG. 1 cools the refrigerant of the Rankine cycle 20 with cooling water that cools the inverter 31.

  Cooling device 30 includes a condenser 24, an inverter 31, a cooling water passage 32, a circulation pump 33, and a radiator 130.

  The condenser 24 has a refrigerant passage through which the refrigerant from the expander 231 flows and a cooling water passage through which the cooling water from the inverter 31 flows. The condenser 24 is connected to the refrigerant passage 22 and the cooling water passage 32. The condenser 24 cools the refrigerant by exchanging heat between the refrigerant of the Rankine cycle 20 and the cooling water of the inverter 31. In the condenser 24, the heat of the refrigerant is radiated to the cooling water to cool the refrigerant, and the cooling water heated by the heat radiated from the refrigerant flows to the radiator 130.

  The radiator 130 cools the cooling water by the wind power of the radiator fan 111.

  The circulation pump 33 supplies the cooling water cooled by the radiator 130 to the cooling water passage 32 of the inverter 31.

  The inverter 31 is provided in the cooling water passage 32 upstream of the condenser 24. The inverter 31 is a control device that controls the electric motor. The inverter 31 converts a DC voltage supplied from the battery into an AC voltage and supplies the AC voltage to the electric motor. As a result, the electric motor rotates to drive the hybrid vehicle.

  As described above, in the cooling device 30, the cooling water supplied from the radiator 130 is caused to flow through the inverter 31 and the condenser 24, and the condenser 24 is cooled together with the inverter 31. Thereby, the refrigerant | coolant of Rankine cycle 20 which passes along the condenser 24 can be cooled. The inverter 31 is provided in the cooling water passage 32 upstream of the condenser 24, but may be provided in the cooling water passage 32 downstream of the condenser 24.

  Next, the cooling performance of the condenser 24 using the radiator 130 will be described.

  FIG. 3 is a diagram showing the cooling capacity of the refrigerant in the Rankine cycle 20 by the cooling water of the inverter 31. In FIG. 3, the vertical axis indicates the temperature of the cooling water at the inlet of the condenser 24, and the horizontal axis indicates the temperature of the outside air. The outside air temperature Y is an upper limit value of the outside air temperature at which the inverter 31 is used.

  The cooling water temperature region 311 indicates the temperature range of the cooling water that varies depending on the operation state of the inverter 31. As the load on the inverter 31 increases, the temperature of the cooling water at the inlet of the condenser 24 increases.

  The radiator 130 is designed so that the inverter 31 does not exceed the upper limit temperature Th, for example, 65 ° C. even when the load of the inverter 31 reaches the upper limit at the outside air temperature Y. For this reason, in the state where the outside air temperature is lower than the temperature Y or the load of the inverter 31 is low, the temperature of the cooling water that has passed through the inverter 31 is sufficiently lower than the upper limit temperature Th, so the refrigerant of the Rankine cycle 20 is cooled. be able to.

  The refrigerant cooling region 312 indicates a temperature range in which the refrigerant of the Rankine cycle 20 can be cooled with the cooling water of the radiator 130 according to the temperature of the outside air. That is, this is a region where the heat of the refrigerant in the Rankine cycle 20 can be cooled by the radiator 130. For example, when 30 ° C. cooling water flows in the condenser 24, the refrigerant in the Rankine cycle 20 is cooled to around 50 ° C.

  As described above, the radiator 130 can cool the refrigerant of the Rankine cycle 20 even when the outside air temperature is close to the temperature Y and the inverter 31 is in a high load state, that is, in a state where the temperature of the cooling water is high.

  According to the first embodiment of the present invention, the condenser 24 is cooled by the cooling water that cools the inverter 31. Then, the condenser 24 cools the refrigerant in the Rankine cycle 20 by exchanging heat between the refrigerant exiting the expander 231 and the cooling water circulating in the inverter 31.

  As a result, the coolant of the Rankine cycle 20 and the inverter 31 can be efficiently cooled together with the cooling water cooled by the radiator 130. For this reason, since it is not necessary to provide a new radiator to cool the refrigerant of the Rankine cycle 20, it is possible to reduce the number of radiators mounted on the hybrid vehicle and to avoid a decrease in the cooling performance of the radiator.

  In the present embodiment, the inverter 31 is provided in the cooling water passage 32 upstream of the condenser 24. In the unlikely event that the bypass valve 26 fails and opens, the high-temperature refrigerant vaporized by the heat exchanger 21 flows directly into the condenser 24, but the inverter 31 is provided upstream of the condenser 24. Therefore, the cooling water overheated by the heat of the refrigerant does not flow to the inverter 31.

  Therefore, the time until the cooling water supplied to the inverter 31 reaches the upper limit temperature can be delayed as the temperature of the cooling water rises due to overheating of the refrigerant. For this reason, it is possible to prevent the inverter 31 from overheating after the Rankine cycle failure is detected and before the Rankine cycle 20 is stopped.

  In addition, even when a clutch provided between the pulley 251 and the refrigerant pump 232 fails, the high-temperature refrigerant may continue to flow into the condenser 24 and exceed the cooling capacity of the radiator 130. In such a case, the inverter 31 is overheated and the hybrid traveling cannot be performed. Therefore, a method for more reliably preventing overheating of the inverter 31 due to Rankine cycle failure will be described below with reference to the drawings.

(Second Embodiment)
FIG. 4 is a diagram showing a heat exchange system 2 according to the second embodiment of the present invention.

  In addition to the heat exchange system 1 shown in FIG. 1, the heat exchange system 2 includes a bypass 30 of the condenser 24, an on-off valve 42, and an on-off valve 43 in the cooling device 30. A rotation speed sensor 233 is provided in the vicinity of the rotation shaft of the expander 231. In addition, since it is the same as that of the heat exchange system 1 about another structure, below, the same code | symbol is attached | subjected and description here is abbreviate | omitted.

  The bypass passage 41 branches from the cooling water passage 32 upstream of the on-off valve 42 and joins the cooling water passage 32 downstream of the condenser 24.

  The on-off valve 42 and the on-off valve 43 switch whether the cooling water from the inverter 31 flows into the condenser 24 or the bypass passage 41. The on-off valve 42 and the on-off valve 43 are controlled by an ECU (Electronic Control Unit) (not shown).

  The on-off valve 42 is provided in the cooling water passage 32 upstream of the condenser 24. The on-off valve 42 opens and closes under the control of the ECU, and shuts off the cooling water flowing through the condenser 24.

  The on-off valve 43 is provided in the bypass passage 41. The on-off valve 43 opens and closes under the control of the ECU, and allows cooling water to flow through the bypass passage 41. The on-off valve 43 opens when the on-off valve 42 is closed, and closes when the on-off valve 42 is open.

  The on-off valve 42 and the on-off valve 43 are switched when a Rankine cycle failure occurs. For example, when a clutch provided in the rotating machine 23 breaks down and high-temperature refrigerant flows from the expander 231 to the condenser 24, and the inverter 31 may reach the upper limit temperature due to heat dissipation of the refrigerant in the condenser 24. The on-off valve 42 and the on-off valve 43 are switched.

  Specifically, when the operation of the Rankine cycle 20 is stopped and the vehicle is traveling at high speed, the ECU closes the on-off valve 42 when the rotational speed sensor 233 detects that the expander 231 is rotating. Open the on-off valve 43. Alternatively, when the signal from the temperature sensor provided in the refrigerant passage 22 exceeds a predetermined temperature threshold, the ECU determines that the Rankine cycle 20 is abnormal and switches the on-off valve 42 and on-off valve 43.

  By switching the on-off valve 42 and the on-off valve 43, the cooling water that has flowed to the condenser 24 flows to the bypass passage 41, so that the cooling water can be prevented from being overheated by the condenser 24. Therefore, it can be avoided that the cooling water rises to a dangerous temperature due to overheating from the refrigerant to the cooling water, and the inverter 31 is overheated. That is, it is possible to eliminate the adverse effects that occur in the inverter 31 due to sharing of the radiator 130.

  According to the second embodiment, by providing the bypass passage 41 in the cooling water passage 32, even if a high-temperature refrigerant is supplied to the condenser 24 when the Rankine cycle 20 is abnormal, the refrigerant is supplied to the cooling water. The temperature rise of the cooling water due to overheating can be suppressed.

  Further, in the present embodiment, when the on-off valve 42 is opened, the on-off valve 43 is closed, and when the on-off valve 42 is closed, the on-off valve 43 is opened so that the cooling water flows into the condenser 24 or into the bypass passage 41. Switch between flowing.

  For this reason, cooling water can be passed only through either the condenser 24 or the bypass passage 41. Thus, when the Rankine cycle 20 is normal, the cooling water flows only through the condenser 24, so that the refrigerant can be efficiently cooled.

  On the other hand, when the Rankine cycle 20 is abnormal, the cooling water flows only in the bypass passage 41, so that it is possible to reliably prevent the cooling water from being overheated by the heat of the refrigerant. That is, the inverter 31 can be reliably protected while efficiently cooling the refrigerant of the Rankine cycle 20.

  In the present embodiment, the on-off valve 42 and the on-off valve 43 are provided in the cooling water passage 32 to switch the flow direction of the cooling water, but a three-way valve may be provided in a portion where the bypass passage 41 branches from the cooling water passage 32. . In this case, the cooling water passage can be switched from the cooling water passage 32 to the bypass passage 41 by providing only one valve, so that the cooling device 30 can have a simple configuration. Next, an example in which a bypass passage is provided in the refrigerant passage 22 in order to bypass the condenser 24 will be described.

(Third embodiment)
FIG. 5 is a diagram showing a heat exchange system 3 according to the third embodiment of the present invention.

  The heat exchange system 3 includes a bypass passage 44, an on-off valve 45, and an on-off valve 46 in the refrigerant passage 22 instead of the bypass passage 41 of the heat exchange system 2. Other configurations are the same as those of the heat exchange system 2.

  The bypass passage 44 branches from the refrigerant passage 22 upstream of the on-off valve 45 and joins the refrigerant passage 22 downstream of the condenser 24.

  The on-off valve 45 and the on-off valve 46 switch whether the refrigerant from the expander 231 flows to the condenser 24 or the bypass passage 44. The on-off valve 45 and the on-off valve 46 are controlled by the ECU.

  The on-off valve 45 is provided in the refrigerant passage 22 upstream of the condenser 24. The on-off valve 45 opens and closes under the control of the ECU, and blocks the refrigerant flowing through the condenser 24.

  The on-off valve 46 is provided in the bypass passage 44. The on-off valve 46 opens and closes under the control of the ECU, and causes the refrigerant to flow through the bypass passage 44. The on-off valve 46 opens when the on-off valve 45 is closed, and closes when the on-off valve 45 is open.

  Similarly to the second embodiment, if the rotation speed sensor 233 detects the rotation of the expander 231 while the Rankine cycle 20 is stopped, the ECU determines that the Rankine cycle 20 is abnormal and opens the on-off valve 45. Close and open the on-off valve 46. Thereby, since the refrigerant from the expander 231 does not flow to the condenser 24, overheating of the cooling water can be prevented by the heat of the refrigerant.

  According to the third embodiment, by providing the bypass passage 44 in the refrigerant passage 22, the supply of the high-temperature refrigerant to the condenser 24 can be stopped when the Rankine cycle 20 is abnormal. Thereby, the temperature rise of the cooling water by the overheating to a cooling water from a refrigerant | coolant can be prevented.

  In the present embodiment, whether the refrigerant from the expander 231 flows to the condenser 24 by closing the on-off valve 46 when the on-off valve 45 is opened and opening the on-off valve 46 when the on-off valve 45 is closed. The flow is switched to the bypass passage 44.

  Thereby, the refrigerant can be passed through only one of the condenser 24 and the bypass passage 44. For this reason, since the refrigerant flows only into the condenser 24 when the Rankine cycle 20 is normal, the refrigerant can be cooled efficiently. On the other hand, when the Rankine cycle 20 is abnormal, the refrigerant flows only in the bypass passage 44, so that it is possible to reliably prevent the cooling water from being overheated by the heat of the refrigerant.

  Furthermore, unlike the second embodiment, one of the on-off valve 42 and the on-off valve 43 does not break down and interrupt the circulation of the cooling water. For this reason, the risk that the electric motor which is a power source of the hybrid vehicle stops due to overheating of the inverter 31 can be reduced.

  In this embodiment, the on-off valve 45 and the on-off valve 46 are provided in the refrigerant passage 22 to switch the flow direction of the refrigerant. However, a three-way valve may be provided at a portion where the bypass passage 44 branches from the refrigerant passage 22. In this case, the cooling device 30 can have a simple configuration.

  In the third embodiment, supply of the refrigerant to the condenser 24 is stopped when the Rankine cycle failure is avoided to avoid overheating of the cooling water, but supply of the refrigerant to the heat exchanger 21 instead of the condenser 24 is performed. You may stop.

(Fourth embodiment)
FIG. 6 is a diagram showing a heat exchange system 4 according to the fourth embodiment of the present invention.

  The heat exchange system 4 includes a bypass passage 51, an on-off valve 52, and an on-off valve 53 in the refrigerant passage 22 instead of the bypass passage 44 of the heat exchange system 3. Other configurations are the same as those of the heat exchange system 3.

  The bypass passage 51 branches from the refrigerant passage 22 upstream of the on-off valve 52 and joins the refrigerant passage 22 downstream of the heat exchanger 21.

  The on-off valve 52 and the on-off valve 53 switch whether the refrigerant from the refrigerant pump 232 flows into the heat exchanger 21 or the bypass passage 51. The on-off valve 52 and the on-off valve 53 are controlled by the ECU. Instead of the on-off valve 52 and the on-off valve 53, a three-way valve may be provided at a portion where the bypass passage 51 branches from the refrigerant passage 22 in order to simplify the configuration.

  The on-off valve 52 is provided in the refrigerant passage 22 upstream of the heat exchanger 21. The on-off valve 52 is opened and closed under the control of the ECU, and blocks the refrigerant flowing through the heat exchanger 21.

  The on-off valve 53 is provided in the bypass passage 51. The on-off valve 53 opens and closes under the control of the ECU, and causes the refrigerant to flow through the bypass passage 51. The on-off valve 53 opens when the on-off valve 52 is closed, and closes when the on-off valve 52 is open.

  For example, when the operation of the Rankine cycle 20 is stopped and the rotation speed sensor 233 detects the rotation of the expander 231, the ECU determines that the Rankine cycle 20 is abnormal, closes the on-off valve 52, Open the on-off valve 53.

  Thereby, since the refrigerant | coolant which flows into the heat exchanger 21 is interrupted | blocked, a refrigerant | coolant is supplied to the condenser 24 via the expander 231, without being heated with the heat exchanger 21. FIG. For this reason, heating of the cooling water by the refrigerant flowing through the condenser 24 can be prevented.

  According to the fourth embodiment, by providing the bypass passage 51 in the refrigerant passage 22, it is possible to reduce the heat radiation of the refrigerant in the heat exchanger 21 when the Rankine cycle 20 is abnormal. Thereby, the temperature rise of the cooling water by the thermal radiation from a refrigerant | coolant to a cooling water can be suppressed. Furthermore, since the low-temperature refrigerant that is not heated by the heat exchanger 21 circulates in the refrigerant passage 22, an electronic device or the like provided in the vicinity of the refrigerant passage 22 is prevented from being damaged by the heat of the refrigerant. be able to.

  In this embodiment, the on-off valve 53 is closed when the on-off valve 52 is opened, and the on-off valve 53 is opened when the on-off valve 52 is closed, so that the refrigerant from the refrigerant pump 232 flows to the heat exchanger 21. Switching to the bypass passage 51.

  For this reason, the refrigerant can be passed through only one of the heat exchanger 21 and the bypass passage 51. Thus, when the Rankine cycle 20 is normal, the refrigerant flows only through the heat exchanger 21, so that the refrigerant can be efficiently vaporized. On the other hand, when the Rankine cycle 20 is abnormal, the refrigerant flows only in the bypass passage 51, so that the heat exchanger 21 can reliably prevent the refrigerant from being heated.

(Fifth embodiment)
FIG. 7 is a diagram showing a heat exchange system 5 according to the fifth embodiment of the present invention.

  The heat exchange system 5 includes a bypass passage 54, an on-off valve 55, and an on-off valve 56 in the cooling water passage 12 instead of the bypass passage 51 of the heat exchange system 4. Other configurations are the same as those of the heat exchange system 4.

  The bypass passage 54 branches from the cooling water passage 12 upstream of the on-off valve 55 and joins the cooling water passage 12 downstream of the heat exchanger 21.

  The on-off valve 55 and the on-off valve 56 switch whether the coolant from the engine 10 flows into the heat exchanger 21 or the bypass passage 54. The on-off valve 55 and the on-off valve 56 are controlled by the ECU. Instead of the on-off valve 55 and the on-off valve 56, a three-way valve may be provided at a portion where the bypass passage 54 branches from the cooling water passage 12 in order to simplify the configuration.

  The on-off valve 55 is provided in the cooling water passage 12 upstream of the heat exchanger 21. The on-off valve 55 opens and closes under the control of the ECU, and shuts off the cooling water flowing to the heat exchanger 21.

  The on-off valve 56 is provided in the bypass passage 54. The on-off valve 56 opens and closes under the control of the ECU, and allows cooling water to flow through the bypass passage 54. The on-off valve 56 opens when the on-off valve 55 is closed, and closes when the on-off valve 55 is open.

  If the rotation of the expander 231 is detected by the rotation speed sensor 233 when the operation of the Rankine cycle 20 is stopped, the ECU determines that the Rankine cycle 20 is abnormal and closes the on-off valve 55. Then, the on-off valve 56 is opened.

  As a result, the cooling water heated by the engine 10 does not flow to the heat exchanger 21, so that the refrigerant in the Rankine cycle 20 is not heated by the heat exchanger 21. Therefore, since the refrigerant that is not heated from the heat exchanger 21 flows to the condenser 24 via the expander 231, it is possible to prevent overheating of the cooling water by the refrigerant.

  According to the fifth embodiment, by providing the bypass passage 54 in the cooling water passage 12, when the Rankine cycle 20 is abnormal, it becomes difficult for the cooling water heated by the engine 10 to flow into the heat exchanger 21. Can be suppressed.

  Thereby, in the condenser 24, the temperature rise of the cooling water due to the heat radiation from the refrigerant to the cooling water of the inverter 31 can be suppressed. Furthermore, since the low-temperature refrigerant circulates in the refrigerant passage 22, it is possible to prevent the electronic device or the like provided in the vicinity of the refrigerant passage 22 from being damaged by the heat of the refrigerant.

  In the present embodiment, the on-off valve 56 is closed when the on-off valve 55 is opened, and the on-off valve 56 is opened when the on-off valve 55 is closed, so that the cooling water from the engine 10 flows into the heat exchanger 21. Switching to the bypass passage 54.

  For this reason, cooling water can be passed only through either the heat exchanger 21 or the bypass passage 54. Thereby, when the Rankine cycle 20 is normal, the cooling water flows only through the heat exchanger 21, so that the refrigerant can be efficiently vaporized.

  On the other hand, when the Rankine cycle 20 is abnormal, the refrigerant flows only in the bypass passage 54, and the cooling water heated by the engine 10 does not flow in the heat exchanger 21, so that the heat of the refrigerant in the heat exchanger 21 is surely prevented. be able to.

(Sixth embodiment)
FIG. 8 is a diagram showing a heat exchange system 6 according to the sixth embodiment of the present invention.

  The heat exchange system 6 includes a bypass passage 71 and an on-off valve 72 in the cooling water passage 32 instead of the bypass passage 54 of the heat exchange system 5. Other configurations are the same as those of the heat exchange system 5.

  The bypass passage 71 branches from the cooling water passage 32 upstream of the on-off valve 72 and joins the cooling water passage 32 downstream of the condenser 24. An inverter 31 is provided in the bypass passage 71.

  The on-off valve 72 is a cooling water passage 32 parallel to the bypass passage 71 and is provided in the cooling water passage 32 upstream of the condenser 24. The on-off valve 72 switches whether the cooling water from the radiator 130 flows to the condenser 24 or the bypass passage 71. The on-off valve 72 is controlled by the ECU. The on-off valve 72 is closed so that the cooling water does not flow into the cooling water passage 32 at the time of Rankine cycle failure.

  The ECU normally opens the on-off valve 72 and closes the on-off valve 72 when an abnormality in the Rankine cycle 20 is detected. As a result, when the refrigerant that has been overheated due to the abnormality of the Rankine cycle 20 flows to the condenser 24, the cooling water that has flowed to the condenser 24 is shut off. It is possible to prevent the cooling water 31 from being overheated.

  According to the sixth embodiment, the bypass passage 71 is provided in the cooling water passage 32. Thereby, since cooling water is distributed to the condenser 24 and the bypass passage 71 provided in parallel, the heat dissipation efficiency to the whole cooling water by the condenser 24 is lowered. For this reason, the temperature rise of the cooling water can be suppressed when the Rankine cycle 20 is abnormal.

  In the present embodiment, the inverter 31 is provided in the bypass passage 71. Thereby, even when the cooling water is overheated by the condenser 24, the cooling water cooled by the radiator 130 is directly distributed also to the cooling water passage of the inverter 31, so that the inverter 31 can be protected.

  In the present embodiment, an on-off valve 72 is provided in the cooling water passage 32 parallel to the bypass passage 71. The on-off valve 72 is closed so that the cooling water does not flow into the cooling water passage 32 when the Rankine cycle fails.

  Thereby, since the on-off valve 72 is open when the Rankine cycle 20 is normal, the refrigerant of the Rankine cycle 20 can be cooled while the inverter 31 is cooled. On the other hand, when the Rankine cycle 20 is abnormal, the on-off valve 72 is closed, so that the cooling water to the condenser 24 can be shut off to prevent overheating of the cooling water by the refrigerant in the Rankine cycle 20.

  Further, unlike the above-described embodiment, the cooling device 30 can be simplified because only one open / close valve 72 is provided in the bypass passage 71 in order to block the cooling water flowing through the condenser 24 while cooling the inverter 31. Can be configured.

(Seventh embodiment)
FIG. 9 is a diagram showing a heat exchange system 7 according to the seventh embodiment of the present invention.

  The heat exchange system 7 includes a bypass passage 73 and an on-off valve 74 in the refrigerant passage 22 instead of the on-off valve 72 of the heat exchange system 6. Other configurations are the same as those of the heat exchange system 6.

  The bypass passage 73 branches from the refrigerant passage 22 upstream from the condenser 24 and joins the refrigerant passage 22 downstream from the condenser 24.

  The on-off valve 74 is provided in the bypass passage 73. The on-off valve 74 switches whether the refrigerant from the expander 231 flows to the condenser 24 or the bypass passage 73. The on-off valve 74 is controlled by the ECU.

  The ECU opens the on-off valve 74 and closes the on-off valve 74 when an abnormality of the Rankine cycle 20 is detected. Thus, when a high-temperature refrigerant flows into the condenser 24 due to an abnormality in the Rankine cycle 20, the refrigerant that has flowed into the condenser 24 by the on-off valve 74 flows into the bypass passage 73, so that the cooling water in the condenser 24 The temperature rise due to overheating of can be reduced.

  According to the seventh embodiment, the bypass passage 73 is provided in the refrigerant passage 22. This makes it difficult for the high-temperature refrigerant to flow into the condenser 24 when the Rankine cycle is abnormal. For this reason, the temperature rise of the cooling water distributed to the condenser 24 can be suppressed, and the temperature rise of the cooling water supplied to the inverter 31 can be suppressed.

  In the present embodiment, an open / close valve 74 is provided in the bypass passage 73. The on-off valve 74 switches whether the refrigerant supplied from the expander 231 flows to the condenser 24 or the bypass passage 73.

  As a result, when the Rankine cycle 20 is normal, the on-off valve 74 is closed, and the refrigerant flows through the condenser 24 to cool the Rankine cycle 20 refrigerant. On the other hand, when the Rankine cycle 20 is abnormal, the on-off valve 74 is opened, and the refrigerant flowing in the condenser 24 is allowed to flow into the bypass passage 73, whereby overheating of the cooling water by the refrigerant can be suppressed. Furthermore, the refrigerant flowing through the condenser 24 can be effectively blocked only by providing one on-off valve 74 in the bypass passage 71.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  In addition, the said embodiment can be combined suitably.

1, 2, 3, 4, 5, 6, 7 Heat exchange system 10 Engine 12 Cooling water passage (Engine cooling water passage)
21 Heat exchanger 22 Refrigerant passage (medium passage)
24 Condenser 31 Inverter (control device)
32 Cooling water passage 41, 71 Bypass passage (cooling water bypass passage)
42 and 43 On-off valve (cooling water switching part)
44, 73 Bypass passage (medium bypass passage)
45, 46, 74 On-off valve (medium bypass switching unit)
51 Bypass passage (heat exchanger bypass passage)
52 and 53 On-off valve (heat exchanger switching part)
54 Bypass passage (engine coolant bypass passage)
55 and 56 On-off valve (engine cooling water switching part)
72 On-off valve (valve to close)
231 Expander

Claims (11)

In a heat exchange system mounted on a hybrid vehicle using the power of an engine and an electric motor,
A Rankine cycle including a heat exchanger that recovers waste heat of the engine into a refrigerant, an expander that generates power using the refrigerant at the outlet of the heat exchanger, and a condenser that condenses the refrigerant that has exited the expander;
A control device for controlling the electric motor, and a cooling water passage through which cooling water for cooling the control device flows,
The heat exchanger system, wherein the condenser is cooled by cooling water that cools the control device. The heat exchange system according to claim 1,
A cooling water bypass passage branched from the cooling water passage upstream of the condenser and joined to the cooling water passage downstream of the condenser;
Heat exchange system. The heat exchange system according to claim 2,
A cooling water switching unit that switches whether the cooling water flows to the condenser or the cooling water bypass passage;
Heat exchange system. In the heat exchange system according to any one of claims 1 to 3,
The control device is provided in a cooling water passage upstream of the condenser.
Heat exchange system. In the heat exchange system according to claim 2 or claim 3,
The control device is provided in the cooling water bypass passage.
Heat exchange system. The heat exchange system according to claim 5,
A valve provided in a cooling water passage parallel to the cooling water bypass passage and further closed so that the cooling water does not flow into the cooling water passage when the Rankine cycle fails;
Heat exchange system. In the heat exchange system according to any one of claims 1 to 6,
A medium bypass passage that branches off from the medium passage upstream of the condenser and joins the medium passage downstream of the condenser;
Heat exchange system. The heat exchange system according to claim 7,
A medium switching unit that switches whether the working medium flows to the condenser or the medium bypass passage;
Heat exchange system. In the heat exchange system according to any one of claims 1 to 8,
A heat exchanger that connects a medium passage through which the working medium flows and an engine cooling water passage through which the engine cooling water flows, and causes heat exchange between the working medium and the engine cooling water to evaporate the working medium by waste heat of the engine;
A heat exchanger bypass passage that branches from the medium passage upstream of the heat exchanger and joins the medium passage downstream of the heat exchanger;
Heat exchange system. The heat exchange system according to claim 9, wherein
A heat exchanger switching unit that switches whether the working medium flows to the heat exchanger or the heat exchanger bypass passage;
Heat exchange system. The heat exchange system according to claim 10 or claim 11,
An engine coolant bypass passage branched from the engine coolant passage upstream of the heat exchanger and joined to the engine coolant passage downstream of the heat exchanger;
An engine coolant switching unit that switches whether the engine coolant flows to the heat exchanger or the engine coolant bypass passage;
Further including a heat exchange system.

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