JP7077680B2 - Rankine cycle system and control method of Rankine cycle system - Google Patents

Description

The present disclosure relates to a Rankine cycle system and a control method for the Rankine cycle system.

Conventionally, in a Rankin cycle in which waste heat of a vehicle engine is transferred to an operating medium via cooling water to generate heat, when the engine is stopped, the cooling water pump is continuously driven even after the engine is stopped. , A Rankin cycle is known in which the Rankin cycle pump circulating the working medium is stopped when the steam pressure of the working medium supplied to the inflator falls below a predetermined pressure (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-66922

By the way, in the Rankine cycle system that transfers heat from the exhaust gas of the engine to the working fluid (working medium), the working fluid is compared with the Rankine cycle system that transfers heat to the working medium via cooling water as in Patent Document 1. The temperature and pressure of the engine will increase. Therefore, immediately after the engine is stopped, the temperature and pressure of the working fluid remain high, so that it is possible to avoid burns due to contact with the devices and members that form the Rankine cycle circuit, and in the Rankine cycle circuit. It is desirable to eliminate the possibility of problems such as leakage of working fluid due to high pressure.

The present disclosure has been made in view of the above, and an object thereof is the Rankine cycle system, which can accelerate the elimination of the high temperature and high pressure state of the working fluid in the Rankine cycle circuit at the end of the operation of the Rankine cycle system. And to provide a control method of the Rankine cycle system.

The Rankin cycle system according to the embodiment of the present invention for achieving the above object includes a working fluid container for storing the working fluid, a working fluid pump for recirculating the working fluid of the working fluid container, and an external heat source. An evaporator that vaporizes the working fluid by receiving heat from the air, an expander that extracts the driving force from the vaporized working fluid, and a condenser that releases heat to the cooling medium to liquefy the working fluid, and controls to control these. In the Rankin cycle system including the device, a temperature detection device for detecting the temperature of the working fluid is provided, and the control device to the expander is based on the temperature and pressure of the working fluid flowing into the expander. If the detection value detected by the temperature detection device is equal to or higher than the preset stop reference value at the time when the operation of the expander is stopped due to the inflow prevention of the working fluid, the detection value is the stop reference. The circulation of the working fluid by the pump for the working fluid and the circulation of the cooling medium for cooling the working fluid in the condenser were continued until the value became less than the value, and the detected value became less than the reference value for stopping. It is characterized by having an operation end control means for stopping the operation of the working fluid pump and stopping the circulation of the cooling medium to the condenser after the time point.

The control method of the Rankin cycle system according to the aspect of the present invention for achieving the above object is a working fluid container for storing the working fluid and a working fluid pump for recirculating the working fluid of the working fluid container. It has an evaporator that receives heat from an external heat source and vaporizes the working fluid, an expander that extracts the driving force from the vaporized working fluid, and a condenser that releases heat to the cooling medium to liquefy the working fluid. In the control method of the Rankin cycle system, when the operation of the Rankin cycle system is stopped, the expansion machine is prevented from flowing into the expansion machine based on the temperature and pressure of the working fluid flowing into the expansion machine. If the temperature of the working fluid is equal to or higher than the preset stop reference value at the time of stopping the operation, the working fluid pump operates until the working fluid temperature becomes lower than the stop reference value. The circulation of the fluid and the circulation of the cooling medium for cooling the working fluid in the condenser are continued, and after the time when the temperature of the working fluid becomes lower than the reference value for stopping, the operation of the pump for the working fluid is started. The method is characterized by stopping and stopping the circulation of the cooling medium to the condenser.

According to the present disclosure, it is possible to expedite the elimination of the high temperature / high pressure state of the working fluid in the circuit of the Rankine cycle system at the end of the operation of the Rankine cycle system.

It is a figure which schematically exemplifies the configuration of the Rankine cycle system of the embodiment of this invention. It is a PV diagram for explanation of Rankine cycle. It is a Ts diagram for the explanation of Rankine cycle. It is a figure which shows an example of the relationship between the measured pressure and the saturation temperature in a saturated water vapor pressure. It is a figure which shows an example of the control flow for carrying out the control method of the Rankine cycle system of embodiment of this invention. It is a figure which shows the detail of "operation end control" of FIG.

Hereinafter, the Rankine cycle system according to the embodiment of the present invention and the control method of the Rankine cycle system will be described with reference to the drawings.

As shown in FIG. 1, the Rankine cycle system 10 utilizes the exhaust heat of the exhaust gas G or the like of a diesel engine (not shown) mounted on the vehicle, and can adjust the pressure to store the working fluid Fw. The working fluid container 11 which is a container, the working fluid pump 12 that recirculates the working fluid Fw of the working fluid container 11, and the working fluid Fw are vaporized by receiving heat from the exhaust gas G (external heat source). It is configured to have an evaporator 13, an expander 14 that takes out a driving force from the vaporized working fluid Fw, and a condenser 15 that releases heat to the cooling medium W to liquefy the working fluid Fw. It is connected by the working fluid flow paths 21 to 25. Further, a bypass flow path 26 that bypasses the expander 14 is provided, and the bypass flow path 26 is provided with a flow path on-off valve (bypass valve) 16 that opens and closes the flow path. Further, a flow path switching device 17 for determining whether the exhaust gas G is guided to the evaporator 13 or discharged without passing through the evaporator 13 is provided.

In this Rankine cycle system 10, a control device 30 for controlling each device including control of the pump rotation speed Np of the working fluid pump 12 is provided, and the temperature T1 of the working fluid Fw flowing into the working fluid pump 12 is provided. A temperature detecting device 31 and a pressure detecting device 41 for detecting the pressure P1 are arranged. Further, a temperature detection device 32 and a pressure detection device 42 for detecting the temperature T2 and the pressure P2 of the working fluid Fw are arranged at the inlet of the evaporator 13, and the working fluid Fw is arranged at the outlet of the evaporator 13. A temperature detection device 33 and a pressure detection device 43 for detecting the temperature T3 and the pressure P3 of the above are arranged.

A temperature detection device 34 and a pressure detection device 44 for detecting the temperature T4 (= Tm) and the pressure P4 (= Pm) of the working fluid Fw flowing into the expander 14 are arranged. Further, a temperature detection device 35 and a pressure detection device 45 for detecting the temperature T5 (= Te) and the pressure P5 (= Pe) of the working fluid Fw flowing into the condenser 15 are arranged.

That is, at least, a temperature detection device that detects the temperatures T1 to T5 of the working fluid Fw on the inlet side of the working fluid pump 12, the outlet side of the evaporator 13, the inlet side of the expander 14, and the inlet side of the condenser 15. 31 to 35 and pressure detecting devices 41 to 45 for detecting the pressures P1 to P5 of the working fluid Fw are provided.

Further, pressure adjusting means 51 and 52 composed of a pressure reducing valve, a back pressure valve, and the like for adjusting the pressure P of the working fluid Fw are installed at the inlet of the evaporator 13 and the inlet of the condenser 15, respectively. These pressure adjusting means 51 and 52 are configured to be remotely controllable.

As the working fluid Fw, it is preferable to use a mixed medium of a two-component system such as water and ethanol, water and methanol, or water and ethylene glycol, but pure water, ethanol only, or a fluoro compound such as a fluorine compound. A refrigerant may be used. As the mixed medium, a mixed medium having a molar ratio of water to ethanol of 50%: 50% will be described here.

Further, the evaporator 13 is composed of a boiler or the like, and as a heat source in the evaporator 13, the exhaust gas G of an in-vehicle diesel engine, particularly the exhaust gas G after passing through an aftertreatment device (not shown) is used as a heat source. However, EGR gas or the like may be used as a heat source.

The expander 14 is composed of a turbine or the like, and is configured so that the driving force of the turbine shaft 14a is transmitted to the axle depending on the use of the extracted energy. When the engine is assisted in rotation, the crank shaft of the engine is connected, and when it is used for power generation, a generator (not shown) is connected. The generated electric power is charged into a battery (not shown) and used as a power source for electrical components (not shown) of a vehicle (not shown) equipped with an engine.

The condenser 15 is also called a condenser, and in the case of water cooling, the condenser 15 is cooled by the cooling water for the engine or the cooling water W for the intercooler discharged from the radiator or the sub-radiator of the engine. In the case of air cooling, a cooling fan (not shown) is arranged and cooled by the outside air.

In this Rankine cycle system 10, as shown in FIGS. 2 and 3, the working fluid Fw stored in the working fluid container 11 is compressed and circulated in the liquid state (C1) by the working fluid pump 12. (Win), in the state of a compressed liquid (C2), is sent to the evaporator 13, where the heat from the exhaust gas G is received (Qin), and the working fluid Fw is vaporized to be superheated steam. do. Then, the working fluid Fw in the state of high-pressure superheated steam (C3) that has been vaporized and heated to a constant pressure is adiabatically expanded by the expander 14 to extract the driving force (Wout), and the state of the low-pressure gas. The working fluid Fw of (C4) is sent to the condenser 15, and the condenser 15 releases heat to the cooling medium W (Qout) to liquefy the working fluid Fw, which is sent to the working fluid container 11. ..

The state of the working fluid Fw in circulation is shown in the PV (pressure-volume) diagram of the working fluid (mixed medium) in FIG. 2 and the Ts (temperature-entropy) diagram of the working fluid shown in FIG. Indicated by. As shown in this figure, adiabatic compression is performed by the working fluid pump 12 between states C1 and C2, and isobaric heating (isobaric heat reception) by the evaporator 13 is performed between states C2 and C3, and states C3 to states. During C4, adiabatic expansion is performed by the expander 14, and between states C4 and C1, isobaric cooling (isobaric heat dissipation) is performed by the condenser 15.

In this Rankine cycle system 10, as the adjusted outlet pressure (adjusting pressure) in the pressure adjusting means 51 and 52 at the inlet of the evaporator 13 and the condenser 15, the evaporator is on the saturated liquid line and the saturated steam line of the working fluid Fw. Pressures corresponding to the temperature of the heat source (exhaust gas) G of 13 and the temperature of the cooling source (cooling medium) W of the condenser 15 are set.

As the pressure setting, for example, as the adjusting pressure of the pressure adjusting means 51 installed at the inlet of the evaporator 13, the pressure corresponding to the temperature of the heat source (exhaust gas) G (for example, about 180 ° C.) on the gas phase line (for example, about 180 ° C.) For example, about 1600 kPa) is set. As a result, the occurrence of insufficient evaporation of the working fluid Fw in the evaporator 13 is suppressed, and reliable heat exchange is performed between the heat source G and the working fluid Fw.

On the other hand, as the adjusting pressure of the pressure adjusting means 52 installed at the inlet of the condenser 15, a pressure corresponding to the temperature of the cooling source (cooling medium: cooling water) W on the liquid phase line (for example, about 1400 kPa) is set. As a result, the occurrence of insufficient condensation of the working fluid Fw in the condenser 15 is suppressed, and reliable heat exchange is performed between the cooling source W and the working fluid Fw.

In this way, the Rankine cycle is set by setting an appropriate temperature and pressure of the working fluid Fw based on the map data of the saturated liquid line and the saturated steam line of the working fluid Fw which are preset and stored in the control device 30. Ensure that reliable heat exchange is carried out in the evaporator 13 and the condenser 15 in the system 10. As a result, waste heat can be regenerated with high efficiency.

Then, the working fluid Fw of the Rankine cycle system 10 is adjusted by controlling the pump rotation speed Np of the working fluid pump 12. This pump rotation speed Np monitors (monitors) the superheat degree Sh of the working fluid Fw in the steam state at the inlet of the expander 14 so that the Rankine cycle system 10 operates reliably, and is the target of the control target which is the desired superheat degree. Adjust so that the degree of superheat is St.

This degree of superheat Sh indicates how many times the temperature of the working fluid Fw in the steam state is higher than the saturation temperature under a specific pressure, and is detected by the measured pressure Pm measured by the pressure detection device 44 and the temperature detection device 34. Based on the measured temperature Tm, for example, the saturation temperature Tv at the measured pressure Pm is obtained from the figure of the saturated water vapor pressure as shown in FIG. 4, and this saturation temperature Tv is subtracted from the measured temperature Tm to obtain the superheat degree Sh. Ask. That is, "Sh = Tm-Tv".

If the superheat degree Sh is high, the energy recovery in the expander 14 becomes insufficient, and if the superheat degree Sh is low, a part of the working fluid Fw is liquefied at the outlet of the expander 14, resulting in damage to the expander 14. Therefore, it is important to operate the Rankine cycle system 10 with an appropriate degree of superheat Sh.

Therefore, in the control of the pump rotation speed Np, the target superheat degree Sh is set as the control target instead of setting the pump rotation speed Np as a direct target so that the superheat degree Sh becomes the target superheat degree Sh. The pump rotation speed Np is feedback-controlled.

Then, in this Rankine cycle system 10, when the control device 30 stops the operation of the expander 14, the detection value T5 (Te) detected by the temperature detection device 35 is equal to or higher than the preset stop reference value Tec. In some cases, the working fluid pump 12 circulates the working fluid Fw and the condenser 15 cools the working fluid Fw until the detected value Te falls below the stopping reference value Tec (eg, engine). The circulation of the cooling water) W is continued, and after the time when the detected value Te becomes less than the stop reference value Tech, the operation of the working fluid pump 12 is stopped and the circulation of the cooling medium W to the condenser 15 is stopped. The operation end control means 30a is provided.

Further, the operation end control means 30a prevents the inflow of heat from the heat source G into the evaporator 13 and the inflow of the working fluid Fw into the expander 14 as an operation for ending the operation of the Rankine cycle system 10. Is configured to do.

Next, the control method of the Rankine cycle system according to the embodiment of the present invention will be described with reference to the control flow shown in FIG. The control method of this Rankine cycle system is to transfer heat from a working fluid container 11 that stores the working fluid Fw, a working fluid pump 12 that recirculates the working fluid Fw of the working fluid container 11, and an external heat source G. It has an evaporator 13 that receives and vaporizes the working fluid Fw, an expander 14 that takes out a driving force from the vaporized working fluid Fw, and a condenser 15 that releases heat to the cooling medium W to liquefy the working fluid Fw. This is a control method for the Rankine cycle system 10.

In this control method, when the operation of the Rankine cycle system 10 is stopped, if the temperature Te of the working fluid Fw is equal to or higher than the preset stop reference value Tech at the time when the operation of the expander 14 is stopped, the operation is performed. Circulation of the working fluid Fw by the working fluid pump 12 and circulation of the cooling water (cooling medium) W for cooling the working fluid Fw by the condenser 15 until the temperature Te of the fluid Fw becomes less than the stop reference value Tech. After the time when the temperature Te of the working fluid Fw becomes less than the stop reference value Tech, the operation of the working fluid pump 12 is stopped and the circulation of the cooling water W to the condenser 15 is stopped.

The control method of the Rankine cycle system 10 can be carried out, for example, by a control flow as shown in FIGS. 5 and 6. The control flows of FIGS. 5 and 6 are called from the advanced control flow when the engine is started, return to the advanced control flow when the engine is stopped, and end at the end of the advanced control flow. Shows.

When the control flow of FIG. 5 starts, the presence or absence of an operation start instruction of the Rankine cycle system 10 is input in step S11. In step S12, it is determined whether or not the operation start instruction is "yes", and if it is not "yes" (NO), after the preset control time has elapsed, the process returns to step S11, and steps S11 and step. Repeat S12 and wait until the operation start instruction becomes "Yes".

If the operation start instruction is "Yes" in step S12 (YES), the process goes to step S13 and "operation start control" is performed. In this "operation start control", the flow path switching device 17 is driven to switch the flow path of the exhaust gas G so that the exhaust gas G flows to the evaporator 13. At the same time as or thereafter, the operation of the working fluid pump 12 is started and the circulation of the cooling water W is started. Then, the rotation speed Np of the working fluid pump 12 is adjusted and controlled, and the state in which the expander 14 can be operated, in other words, the temperature Tm (T4) and the pressure Pm (P4) on the inlet side of the expander 14 are set in advance. Keep within the operating temperature range and operating pressure range.

Further, when the temperature Tm (T4) and the pressure Pm (P4) on the inlet side of the expander 14 enter the preset operating temperature range and operating pressure range, the flow path opening / closing of the bypass flow path 26 bypassing the expander 14 The valve 16 is closed. As a result, the inflator 14 is started to be driven, and the Rankine cycle system 10 is in the operating state.

In the "operation control" of the next step S14, the temperatures T1 to T5 detected by the temperature detecting devices 31 to 35 and the pressures P1 to detected by the pressure detecting devices 41 to 45 regarding the working fluid Fw of the Rankine cycle system 10 By monitoring P5, all the detected values T1 to T5 and P1 to P5 of these detected values T1 to T5 and P1 to P5 are the reference values for interruption T1a to T5a preset for each detected value. The operating state of the Rankine cycle system 10 is maintained so that the temperature does not exceed P1a to P5a.

After performing the "operation control" in step S14 for a preset control time, the process goes to step S15 to determine whether or not the operation end instruction is "yes", and if it is not "yes" (NO). ), Return to step S14, repeat step S14 and step S15, and wait until the operation end instruction becomes "Yes". If the operation end instruction is "Yes" in step S15 (YES), the process proceeds to the "operation end control" in step S20.

As shown in the control flow of FIG. 6, in the “operation stop control” of step S20, first, in the “switching of the flow path switching device” of step S21, the flow path switching device 17 is driven to drive the exhaust gas G. Switches the flow path so as to bypass the evaporator 13. That is, the inflow of heat from the heat source G into the evaporator 13 is prevented.

In the next step S22, the temperature T4 (Tm) detected by the temperature detection device 34 related to the inflator 14 and the pressure P4 (Pm) detected by the pressure detection device 44 are input, and in the next step S23, these are input. It is determined whether or not the temperature Tm and the pressure Pm of the above are “temperature and pressure” capable of operating the inflator 14. If the determination in step S23 is "temperature and pressure" that allows the inflator 14 to be operated (YES), there is no heat input from the heat source of the exhaust gas G until the preset control time elapses. In this state, the working fluid Fw is refluxed to continue the operation of the inflator 14, and the process returns to step S22. By this control, the operation of the inflator 14 is continued while the output of the mechanical energy is stably obtained, so that the thermal energy possessed by the working fluid Fw can be sufficiently used.

Then, when the temperature Tm and the pressure Pm become the "temperature and pressure" at which the inflator 14 cannot be operated in the determination in step S23, the process proceeds to the "stop operation of the inflator" in step S24. In the "stop operation of the expander" in step S24, the flow path on-off valve (bypass valve) 16 is opened to prevent the working fluid Fw from flowing to the expander 14. That is, the inflow of the working fluid Fw into the expander 14 is blocked. On the other hand, the operation of the working fluid pump 12 and the circulation of the cooling water W to the condenser 15 are continuously performed without stopping.

In this control flow, the engine is stopped and the inflator 14 is stopped separately, but the engine is stopped based on the necessity of operating the engine, while the inflator 14 is stopped. The stoppage is related to the necessity of extracting mechanical energy and the operation of the engine. Therefore, the inflator 14 may be stopped even while the engine is running, the inflator 14 may be stopped, or the Rankine cycle system 10 may be stopped before the engine is stopped. Therefore, the engine may be stopped and the expander 14 may be stopped at the same time or individually.

In the next step S25, the temperature T5 (Te) detected by the temperature detection device 35 related to the condenser 15 and the pressure P5 (Pe) detected by the pressure detection device 45 are input, and in the next step S26, this is performed. It is determined whether at least one of whether the temperature Te is equal to or less than the preset stop reference value Tec or the pressure Pe is equal to or less than the preset stop reference value Pec is satisfied. In other words, it is determined whether the temperature of the working fluid Fw is equal to or lower than the preset temperature. Normally, it is determined by the temperature T5 (Te) of the working fluid Fw at the inlet of the condenser 15 related to the cooling water W, but the pressure P5 (Pe) of the working fluid Fw at the inlet of the condenser 15 is the temperature. Since it has a close relationship with T5 (Te), it may be determined by this pressure P5 (Pe). Further, since the working fluid Fw continues to circulate, it may be determined by using any of the other temperatures T1 to T4 and the pressures P1 to P4.

If the temperature of the working fluid Fw is not equal to or lower than the preset temperature in the determination of step S26 (NO), the process returns to step S25 after the preset control time has elapsed. As a result, both the working fluid Fw and the cooling water W are circulated to promote the cooling of the working fluid Fw and the cooling of the entire circuit. Then, if the temperature of the working fluid Fw becomes equal to or lower than the preset temperature in the determination of step S25 (YES), the process proceeds to step S27 "stopping the working fluid pump and stopping the cooling water pump". ..

In step S27, “Stopping the working fluid pump and stopping the cooling water pump”, the temperature of the working fluid Fw becomes lower than the preset temperature, and the temperature and pressure of the working fluid Fw are lowered to a safe range. Therefore, the operation of the working fluid pump 12 is stopped, the operation of the cooling water pump (not shown) that circulates the cooling water W is stopped, and the circulation of the cooling water W is stopped. The stop of the circulation of the working fluid Fw and the stop of the circulation of the cooling water W may be stopped at the same time or sequentially, and after stopping one, the other is stopped after a certain time. You may.

That is, the circulation of the working fluid Fw by the working fluid pump 12 until the temperature Te of the working fluid Fw becomes less than the stop reference value Tech or the pressure Pe of the working fluid Fw becomes less than the stop reference value Pec. , The circulation of the cooling water (cooling medium) W for cooling the working fluid Fw in the condenser 15 is continued, and after the temperature Te of the working fluid Fw becomes less than the stop reference value Tech, or after the working fluid After the time when the pressure Pe of Fw becomes less than the reference value Pec for stopping, the operation of the working fluid pump 12 is stopped and the circulation of the cooling water W to the condenser 15 is stopped. As the stop reference values Tec and Pec, for example, a temperature and a pressure can be set so that all the working fluids Fw in the circuit of the Rankine cycle system 10 are in a liquid state.

Then, by stopping both of these cycles, the "operation end control" in step S20 is completed. Then, the process returns to step S11, and steps S11 to S20 are repeated. In the control flow of FIG. 5, when a signal for stopping the engine that supplies the exhaust gas G, which is the drive source of the Rankine cycle system 10, is received, an interrupt occurs in the middle of the control, and the control ends the operation in step S20. It goes through control to return, returns to the advanced control flow, and this control ends at the end of the advanced control flow.

By the above-mentioned operation end control means 30a and the above-mentioned control, the working fluid Fw and the cooling water W are circulated even after the engine is stopped and the expander 14 is stopped. That is, operate both the working fluid pump 12 and the cooling water pump until the temperature and pressure of the working fluid Fw drop to a safety line (eg, do not touch and burn, residual pressure on the equipment). Will continue. As a result, the temperature and pressure of the working fluid Fw in the circuit of the Rankine cycle system 10 can be quickly lowered to a safe range after the inflator 14 is stopped, and the working medium Fw can be lowered while the operation of the Rankine cycle system 10 is stopped. It is possible to make it difficult for troubles such as leakage from the circuit and burst of the circuit to occur.

Therefore, according to the above-mentioned Rankine cycle system 10 and the control method of the Rankine cycle system, the high temperature and high pressure state of the working fluid in the circuit of the Rankine cycle system 10 can be quickly eliminated at the end of the operation of the Rankine cycle system 10. , The possibility that the circuit of the Rankine cycle system 10 is disturbed can be reduced.

10 Rankine cycle system 11 Working fluid container 12 Working fluid pump 13 Evaporator 14 Inflator 15 Condenser 16 Flow path on-off valve (bypass valve)
26 Bypass flow path 30 Control device 31 to 35 Temperature detection device 41 to 45 Pressure detection device 51, 52 Pressure adjusting means Fw Working fluid (working medium)
G Exhaust gas (heat source)
W Cooling water Np Rotation speed P1, P2, P3, P4 (= Pm), P5 (= Pe) Measurement pressure T1, T2, T3, T4 (= Tm), T5 (= Te) Measurement temperature

Claims (4)

A working fluid container that stores the working fluid, a working fluid pump that recirculates the working fluid of the working fluid container, an evaporator that vaporizes the working fluid by receiving heat from an external heat source, and a vaporized working fluid. In the Rankine cycle system, which has an expander that draws driving force from the cooling medium, a condenser that releases heat to the cooling medium to liquefy the working fluid, and a control device that controls these.
In addition to providing a temperature detection device that detects the temperature of the working fluid,
The control device
When the operation of the inflator is stopped due to the prevention of the inflow of the working fluid into the inflator based on the temperature and pressure of the working fluid flowing into the inflator, the detection value detected by the temperature detection device is preset. If it is equal to or higher than the stop reference value, circulation of the working fluid by the working fluid pump and cooling for cooling the working fluid by the condenser until the detected value becomes less than the stop reference value. Operation end control that continues the circulation of the medium and stops the operation of the working fluid pump and the circulation of the cooling medium to the condenser after the time when the detected value becomes less than the stop reference value. A Rankine cycle system characterized in that it is configured with means. The operation end control means is configured to prevent the heat from the heat source from flowing into the evaporator when it is determined that there is an instruction to stop the supply of the heat source. The Rankine cycle system according to claim 1. The Rankine cycle system according to claim 1 or 2, wherein the heat source is exhaust gas of an internal combustion engine, and the cooling medium for cooling the working fluid in the condenser is engine cooling water of the internal combustion engine. .. A working fluid container that stores the working fluid, a working fluid pump that recirculates the working fluid in the working fluid container, an evaporator that receives heat from an external heat source and vaporizes the working fluid, and a vaporized working fluid. In the control method of the Rankine cycle system, which comprises an expander that draws driving force from the cooling medium and a condenser that releases heat to a cooling medium to liquefy the working fluid.
When the operation of the Rankine cycle system is stopped, when the operation of the inflator is stopped by blocking the inflow of the working fluid into the inflator based on the temperature and pressure of the working fluid flowing into the inflator, the working fluid of the working fluid is stopped. When the temperature is equal to or higher than the preset stop reference value, the working fluid is circulated by the working fluid pump and the working fluid by the condenser until the temperature of the working fluid becomes lower than the stopping reference value. The circulation of the cooling medium for cooling is continued, and after the temperature of the working fluid becomes lower than the reference value for stopping, the operation of the pump for the working fluid is stopped and the cooling medium to the condenser is stopped. A method of controlling a Rankine cycle system, characterized by stopping the circulation.

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