JP2022059185A - Rankine cycle system of vehicle and control method for rankine cycle system of vehicle - Google Patents

Abstract

To provide a Rankine cycle system of a vehicle capable of avoiding reduction in regeneration output of an expander and a regeneration output impossible state to increase opportunities for waste heat recovery.SOLUTION: A Rankine cycle system 1 of a vehicle is configured to, when a heater 29 is arranged between an evaporator 17 and an expander 18 in a working fluid flow path 15, and a rotation speed Sp of a pump 16 changes from a decreasing state to an increasing state, perform control to heat working fluid W by driving the heater 29.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to a vehicle Rankine cycle system and a method for controlling a vehicle Rankine cycle system.

In the Rankine cycle system of a vehicle, a technique has been proposed in which a pipe for a working fluid between an outlet of an evaporator and an inlet of an expander is covered with a heating device such as a heater (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2020-051398

By the way, in the Rankine cycle system of a vehicle, the rotation speed of a pump that pumps a working fluid is adjusted so as to have a positive correlation with the flow rate and temperature of the exhaust of an engine (internal combustion engine). Therefore, when the flow rate and temperature of the exhaust gas shift from the lowered state to the raised state, the rotation speed of the pump rises sharply. As a result, there is a problem that the amount of heat received per unit flow rate of the working fluid in the evaporator decreases due to the increase in the flow rate of the working fluid. The decrease in the amount of heat received by the working fluid is a factor that causes the regenerative output of the expander to decrease or the regenerative output to be impossible due to the decrease in the energy amount of the working fluid that rotates the expander. If such a situation occurs, it will take some time for the regenerative output of the expander to stabilize.

An object of the present disclosure is to provide a control method for a vehicle Rankine cycle system and a vehicle Rankine cycle system that increase the chances of waste heat recovery by avoiding a decrease in the regenerative output of the expander or a state in which the regenerative output cannot be performed. To do.

The vehicle Rankine cycle system of the embodiment of the present invention for achieving the above object controls the flow path of the working fluid in which the pump, the evaporator, the expander, and the condenser are arranged in the order of flowing the working fluid. A device is provided, the evaporator exchanges heat between the waste heat fluid of the internal combustion engine and the working fluid, and the control device adjusts the rotation speed of the pump to adjust the rotation speed of the pump and the internal combustion engine. In the Rankine cycle system of a vehicle that controls the flow rate and temperature of the exhaust in the exhaust passage of the vehicle to have a positive correlation with each other, the heater arranged in the flow path between the evaporator and the expander and the heater. The control device includes a parameter acquisition device for acquiring parameters related to the rotation speed of the pump, and the control device shifts from a state in which the rotation speed of the pump decreases to a state in which the rotation speed increases based on the parameters acquired by the parameter acquisition device. When it is determined that the heater is driven, the working fluid is controlled to be heated.

Further, the method for controlling the Rankine cycle system of the vehicle according to the embodiment of the present invention for achieving the above object is to control the working fluid in which the pump, the evaporator, the expander, and the condenser are arranged in the order in which the working fluid flows. A flow path is provided, and the evaporator exchanges heat between the waste heat fluid of the internal combustion engine and the working fluid, and the rotation speed of the pump is adjusted so that the rotation speed of the pump and the exhaust passage of the internal combustion engine can be adjusted. In the control method of the Rankine cycle system of a vehicle that controls to make each of the exhaust flow rate and the temperature positively correlated, the step of sequentially acquiring the parameters related to the pump rotation speed and the pump rotation speed decrease. Between the evaporator and the inflator when it is determined that the pump has transitioned from a decreasing state to an ascending state and a step of determining whether or not the pump has transitioned from a declining state to an ascending state. It is a method characterized by having a step of driving an arranged heater to heat a working fluid flowing into the inflator.

According to the present disclosure, it is possible to increase the chances of recovering waste heat by avoiding a decrease in the regenerative output of the expander or a state in which the regenerative output cannot be performed.

It is a block diagram which illustrates the Rankine cycle system of the vehicle of 1st Embodiment. It is a block diagram which illustrates the structure of the rotation speed control of a pump in the control device of FIG. It is a time chart diagram which illustrates the transition of each parameter and time about the Rankine cycle system of FIG. It is a block diagram which illustrates the structure of the energization amount control of a heater in the control device of FIG. It is a flow diagram which illustrates the control method of the Rankine cycle system of the vehicle of 1st Embodiment. It is a time chart diagram which illustrates the transition of each parameter and time about the Rankine cycle system of the vehicle of 2nd Embodiment. It is a flow diagram which illustrates the control which maintains the degree of superheat among the control methods of the Rankine cycle system of the vehicle of 2nd Embodiment. It is a flow diagram which illustrates the control which drives a heater among the control methods of the Rankine cycle system of the vehicle of 2nd Embodiment.

Hereinafter, the Rankine cycle system (hereinafter referred to as “Rankin cycle system”) 1 of the vehicle according to the embodiment of the present disclosure will be described with reference to the drawings.

The vehicle provided with the Rankine cycle system 1 of the present embodiment includes an engine (internal combustion engine) 2. As illustrated in FIG. 1, the engine 2 is a device that generates power by mixed combustion of fresh air A and fuel F inside each of a plurality of (four in this embodiment) cylinders 2a. The fuel F is supplied from the fuel injection device 2b arranged inside each cylinder 2a. The power of the engine 2 is mainly used for traveling a vehicle having the engine 2 inside.

The intake passage 3 is connected to each cylinder 2a via an intake manifold. The intake passage 3 is a passage for supplying fresh air A introduced from the atmosphere to each cylinder 2a. The exhaust passage 4 is connected to each cylinder 2a via an exhaust manifold. The exhaust passage 4 is a passage for discharging the exhaust G generated by the mixed combustion inside each cylinder 2a to the atmosphere.

A compressor 5a of the turbocharger 5 is arranged in the intake passage 3. In the exhaust passage 4, the turbine 5b of the turbocharger 5, the exhaust valve 6, the oxidation catalyst device 7, the filter 8, the selective reduction catalyst device 9, and the ammonia slip catalyst device 10 are in this order from the upstream side in the flow of the exhaust G. , And a three-way valve 11 is arranged.

The turbocharger 5 is a variable capacity turbocharger in which a compressor 5a and a turbine 5b are connected via a connecting shaft 5c. The turbocharger 5 transmits the rotational power of the turbine 5b driven by the energy of the exhaust G to the compressor 5a via the connecting shaft 5c, and the fresh air A passing through the intake passage 3 by the rotational power of the compressor 5a. Is pumped. The exhaust valve 6 limits the flow rate of the exhaust G from each cylinder 2a toward the atmosphere according to the opening degree of the valve.

In the oxidation catalyst device 7, an oxidation catalyst is supported on an internal carrier, and the hydrocarbons and carbon monoxide contained in the exhaust G are oxidized by the action of the oxidation catalyst. The filter 8 collects particulate matter (PM: Particulate Matter) contained in the exhaust gas G. In the present embodiment, the oxidation catalyst device 7 and the filter 8 are integrally arranged inside the same converter provided in the exhaust passage 4, but may be separately arranged.

In the selective reduction catalyst device 9, a selective reduction catalyst (NOx purification catalyst) is supported on an internal carrier. A urea water injection device (not shown) is arranged in the exhaust passage 4 in the front stage of the selective reduction catalyst device 9. Ammonia obtained by hydrolyzing urea water injected from the urea water injection device with the calorific value of exhaust G is supplied to the selective reduction catalyst device 9, and NOx adsorbed on the selective reduction catalyst is reduced with ammonia. ..

In the ammonia slip catalyst device 10, an oxidation catalyst is supported on an internal carrier, and ammonia contained in the exhaust G flowing out from the selective reduction catalyst device 9 is oxidized. In the present embodiment, the selective reduction catalyst device 9 and the ammonia slip catalyst device 10 are integrally arranged inside the same converter provided in the exhaust passage 4, but may be separately arranged.

The three-way valve 11 switches the flow path of the exhaust G flowing out from the ammonia slip catalyst device 10 to at least one of the exhaust passage 4a on the atmospheric side or the exhaust passage 4b on the evaporator 17 side described later. The exhaust passage 4a is a passage that communicates with the atmosphere. The exhaust passage 4b is a passage that passes through the evaporator 17.

The exhaust passage 4 on the upstream side of the turbine 5b and the intake passage 3 on the downstream side of the compressor 5a (intake manifold in this embodiment) are connected by a return passage 12. The recirculation passage 12 is a passage for recirculating a part of the exhaust G from the exhaust passage 4 to the intake passage 3 as a recirculation exhaust Ge. In the recirculation passage 12, a recirculation exhaust cooler 13 and a recirculation exhaust valve 14 are arranged in order from the upstream side in the flow of the recirculation exhaust Ge. The recirculation exhaust cooler 13 cools the recirculation exhaust Ge by exchanging heat between the recirculation exhaust Ge and a cooling medium (for example, cooling water). The recirculation exhaust valve 14 regulates the flow rate of the recirculation exhaust Ge passing through the recirculation passage 12.

The Rankine cycle system 1 of the present embodiment is a system that recovers the waste heat of the exhaust G of the engine 2 and converts the recovered waste heat into power or electric power to assist the driving of the engine 2 and the like. The Rankine cycle system 1 includes a pump 16, an evaporator 17, an expander 18, a condenser 19, and a tank 20 in order from the upstream side in the flow direction of the working fluid W in the flow path 15 of the working fluid. ing. As the working fluid W, for example, cooling water is exemplified.

The flow path 15 of the working fluid W is a flow path through which the working fluid W circulates and is a closed flow path. The pump 16 pumps the working fluid W in a liquid state. The evaporator 17 exchanges heat between the working fluid W in a liquid state and the exhaust (waste heat fluid) G to heat the working fluid W and evaporate it. The expander 18 is rotationally driven by the working fluid W in a gaseous state. The generator 21 connected to the inflator 18 generates electricity by the driving force of the inflator 18. Whether or not power is transmitted from the expander 18 to the generator 21 by arranging a clutch (not shown) between the expander 18 and the generator 21 and switching the disengagement state of the clutch. You may switch. Further, the generator 21 is an example of a device for recovering the power of the expander 18. The device for recovering the power of the expander 18 is not limited to the generator 21.

The condenser 19 is arranged on a flow path through which cooling water (for example, engine cooling water) We passes, and heat exchanges between the working fluid W and the cooling water We to cool and condense the working fluid W. The tank 20 stores the working fluid W in a liquid state inside.

The Rankin cycle system 1 of the present embodiment includes a vehicle speed sensor 22, an exhaust temperature sensor 23, an exhaust flow rate sensor 24, a working fluid temperature sensor 25, a working fluid pressure sensor 26, an information acquisition device 27, and a heater 29. , And a control device 28.

The vehicle speed sensor 22 acquires the speed V of the vehicle. The exhaust temperature sensor 23 acquires the exhaust temperature Tg, which is the temperature of the exhaust G passing through the exhaust passage 4. The exhaust flow rate sensor 24 acquires an exhaust flow rate Vg, which is the flow rate of the exhaust G passing through the exhaust passage 4. The working fluid temperature sensor 25 acquires the temperature Tw of the working fluid W flowing in the flow path between the evaporator 17 and the expander 18. The working fluid pressure sensor 26 acquires the pressure Pw of the working fluid W flowing through the flow path 15 between the evaporator 17 and the expander 18. Each of the above-mentioned sensors is not limited to the sensor that directly acquires the target parameter, and may be configured by a device that indirectly acquires the target parameter. For example, the speed V may be a value estimated from the rotation speed of the crank shaft of the engine 2. The exhaust temperature Tg may be a value estimated from the combustion state of the engine 2, and the exhaust flow rate Vg may be a value estimated from the pressure of the exhaust G. Further, the temperature Tw may be a value estimated from the temperature of the working fluid W flowing through the flow path 15 between the pump 16 and the evaporator 17 and the exhaust temperature Tg, and the pressure Pw is the operation obtained according to the rotation speed of the pump 16. It may be a value estimated from the flow rate of the fluid W.

The information acquisition device 27 acquires the travel route information of the vehicle. The traveling route information of the vehicle is information including at least the road surface gradient in the traveling route where the vehicle is planned to travel and the section where the road surface gradient continues. As the information acquisition device 27, a navigation system that guides a traveling route to the destination of the vehicle is exemplified.

The vehicle speed sensor 22 of the first embodiment functions as a parameter acquisition device for acquiring parameters related to the rotation speed of the pump 16. It suffices if the parameter acquisition device can acquire a parameter capable of determining a rapid increase in the rotation speed of the pump 16. In the present disclosure, the rapid increase in the rotation speed of the pump 16 is a state in which the rotation speed of the pump 16 shifts from a decreased state to an increased state, and the working fluid W in the evaporator 17 due to an increase in the flow rate of the working fluid W. It is a state in which the amount of heat received per unit flow rate decreases. As will be described later, the rotation speed Sp of the pump 16 is adjusted so as to have a positive correlation with the exhaust temperature Tg and the exhaust flow rate Vg, and the changes in the exhaust temperature Tg and the exhaust flow rate Vg depend on the running state of the vehicle. Will change. The parameter acquisition device may directly acquire the rotation speed Sp of the pump 16, or may acquire either the exhaust temperature Tg and the exhaust flow rate Vg related to the rotation speed Sp of the pump 16 and the running state of the vehicle. good. It is desirable that the parameter acquisition device takes a long time from acquiring the parameters until the flow rate of the working fluid W changes, and among the rotation speed Sp of the pump 16, the exhaust temperature Tg, the exhaust flow rate Vg, and the running state of the vehicle. It is more desirable to be the running state of the vehicle, which is the first parameter to change in. In the present embodiment, the vehicle speed sensor 22, which is a parameter acquisition device, sequentially acquires the vehicle speed V and stores it in the internal storage device of the control device 28.

The working fluid temperature sensor 25 and the working fluid pressure sensor 26 of the first embodiment function as a control value acquisition device. The control value acquisition device is a device that acquires at least one of the temperature Tw and the degree of superheat Hw of the working fluid W flowing through the flow path 15 between the evaporator 17 and the expander 18 as the control value used for the drive control of the heater 29. be. The control value acquisition device is configured to be able to acquire the temperature Tw and the degree of superheat Hw of the working fluid W on the upstream side with respect to the flow of the working fluid W from the heater 29 in the flow path 15 between the evaporator 17 and the expander 18. Therefore, the working fluid temperature sensor 25 and the working fluid pressure sensor 26 are arranged in the flow path 15 between the evaporator 17 and the heater 29. In the present disclosure, the degree of superheat Hw is determined by the temperature Tw and the pressure Pw of the working fluid W, and is indicated by the difference between the saturation temperature and the temperature Tw at the pressure Pw.

The heater 29 may be arranged in the flow path 15 between the evaporator 17 of the flow path 15 and the expander 18, and may be able to heat the working fluid W, and an electric heater driven by electricity is exemplified.

The control device 28 is hardware composed of a CPU (Central Processing Unit) that performs various information processing, an internal storage device that can read and write programs and information processing results used for performing the various information processing, and various interfaces. Is. The control device 28 is electrically connected to various devices 22 to 27 and a heater 29 described later. The control device 28 controls to adjust the rotation speed Sp of the pump 16 and controls to drive the heater 29.

As illustrated in FIG. 2, the control device 28 has a rotation rate map 28a, a target superheat degree map 28b, and an amplification degree k1, the control value is the rotation rate Sp of the pump 16, and the target value is the superheat degree Hw. The feedback control is controlled to adjust the rotation speed Sp of the pump 16 by a control method incorporating feedforward control in which the disturbance is the exhaust temperature Tg and the exhaust flow rate Vg.

The rotation speed map 28a is map data showing the relationship between the exhaust flow rate Vg and the exhaust temperature Tg and the first target rotation speed Spa, which is the target value of the rotation speed of the pump 16. In the rotation speed map 28a, the first target rotation speed Spa has a positive correlation with the exhaust flow rate Vg, and the first target rotation speed Spa increases as the exhaust flow rate Vg increases. Further, the first target rotation speed Spa has a positive correlation with the exhaust temperature Tg, and the first target rotation speed Spa increases as the exhaust temperature Tg increases.

The target superheat degree map 28b is map data showing the relationship between the exhaust flow rate Vg and the exhaust temperature Tg and the target superheat degree Hwm which is the target value of the superheat degree Hw of the working fluid W. In the target superheat degree map 28b, the target superheat degree Hwm has a positive correlation with the exhaust flow rate Vg, and the target superheat degree Hwm becomes higher as the exhaust flow rate Vg increases. Further, the target superheat degree Hwm has a positive correlation with the exhaust temperature Tg, and the target superheat degree Hwm increases as the exhaust temperature Tg increases.

The degree of amplification (also referred to as gain) k1 is a value obtained in advance from an experiment, a test, or a simulation. The amplification degree k1 is an adjustment amount of the rotation speed of the pump 16 that makes the difference between the target superheat degree Hwm and the actual superheat degree Hw obtained from the detected values of the working fluid temperature sensor 25 and the working fluid pressure sensor 26 zero. It is a value to obtain the rotation speed Spb. The amplification degree k1 is multiplied by the difference ΔT obtained by subtracting the superheat degree Hw from the target superheat degree Hwm to obtain the adjusted rotation speed Spb (= k1 × ΔT).

The control device 28 obtains the target rotation speed Spm (= Spa + Spb) by adding the adjusted rotation speed Spb to the first target rotation speed Spa. The control device 28 adjusts the rotation speed Sp of the pump 16 to the target rotation speed Spm.

In the rotation speed control of the pump 16 of the present embodiment, the superheat degree Hw is used as the target value, but the temperature Tw of the working fluid W may be used as the target value. In that case, instead of the target superheat degree map 28b and the amplification degree k1, the exhaust flow rate Vg and the target temperature map showing the relationship between the exhaust temperature Tg and the target temperature of the working fluid W, and the difference between the target temperature and the actual temperature Tg are displayed. The amplification degree at which the adjustment amount of the rotation speed of the pump 16 to be zero is obtained is used.

As illustrated in FIG. 3, the control device 28 controls the drive of the heater 29 based on the running state of the vehicle that correlates with the rotation speed Sp of the pump 16. Times t1 to t2 in FIG. 3 indicate a period of deceleration of the vehicle, and times t2 to t3 indicate a period of acceleration of the vehicle.

The control device 28 determines whether or not the rotation speed Sp of the pump 16 shifts from a decreasing state to an increasing state based on the speed V detected by the vehicle speed sensor 22, and the traveling state of the vehicle changes from the decelerating state to the accelerating state. It is determined whether or not the transition is made, and if it is determined that the traveling state of the vehicle has changed from the deceleration state to the acceleration state, it is determined that the rotation speed of the pump 16 has changed from the decreasing state to the increasing state. Next, the control device 28 energizes the heater 29 to start driving the heater 29, and starts controlling to heat the working fluid W flowing into the expander 18. After that, the control device 28 stops driving the heater 29 when the actual superheat degree Hw becomes equal to or higher than the target superheat degree Hwm.

The deceleration state is determined in a state in which the speed V detected by the vehicle speed sensor 22 is sequentially reduced in a preset section or time during which the vehicle has traveled. It is desirable that the deceleration state is a state indicating that the rotation speed Sp of the pump 16 has become the low rotation speed side in the rotation speed range due to the deceleration of the vehicle. In the present disclosure, the degree of decrease in the interval or time and speed V can be tested and tested in advance so that it can be determined in the rotation speed control of the pump 16 that the rotation speed Sp of the pump 16 is on the low rotation speed side in the rotation speed range. , Or set by simulation. Further, the rotation speed range is a range in which the rotation speed Sp of the pump 16 can be adjusted, and the low rotation speed side indicates the division on the low rotation speed side when the rotation speed range is divided into a plurality of ranges according to the height.

Further, it is more desirable that the deceleration state is such that the speed V detected by the vehicle speed sensor 22 in the section or time is equal to or higher than the preset vehicle speed V1. The set vehicle speed V1 is set in advance by an experiment, a test, or a simulation so that it can be determined that the running state of the vehicle is in a decelerated state and the superheat degree Hw is lower than the target superheat degree Hwm. When the superheat degree Hw is lower than the target superheat degree Hwm, the expander 18 is also stalled.

Unlike the deceleration state, the acceleration state does not set a section or time, and is determined in a state where the vehicle speed V detected by the vehicle speed sensor 22 is faster than the vehicle speed detected in the previous cycle.

As illustrated in FIG. 4, the amount of energization during driving of the heater 29 is the actual superheat obtained from the detected values of the working fluid temperature sensor 25 and the working fluid pressure sensor 26 from the target superheat degree Hwm obtained from the target superheat degree map 28b. It is adjusted based on the difference ΔT obtained by subtracting the degree Hw. Specifically, the energization amount is adjusted by feedforward control in which the disturbance is the superheat degree Hw and the target value is the energization amount, and the amplification degree k2 is obtained so that the difference ΔT becomes zero. In the feedforward control for adjusting the energization amount when the heater 29 is driven, the energization amount becomes zero when the difference ΔT between the target superheat degree Hwm and the superheat degree Hw becomes zero. The energization amount may be adjusted by feedforward control in which the disturbance is the temperature Tg and the target value is the energization amount.

The drive of the heater 29 is stopped when the actual superheat degree Hw obtained from the detection values of the working fluid temperature sensor 25 and the working fluid pressure sensor 26 becomes equal to or more than the target superheat degree Hwm obtained from the target superheat degree map 28b. In the present disclosure, stopping the drive of the heater 29 means that the feedforward control of the energization amount of the heater 29 is stopped, and does not include the case where the energization amount in the feedforward control is zero.

As illustrated in FIG. 5, the control method of the Rankine cycle system 1 of the vehicle of the first embodiment is repeated at predetermined cycles while the vehicle is running. The predetermined cycle is a cycle for detecting the target parameters of each of the vehicle speed sensor 22, the exhaust temperature sensor 23, the exhaust flow rate sensor 24, the working fluid temperature sensor 25, and the working fluid pressure sensor 26.

When the control flow of FIG. 5 starts, the running state of the vehicle is decelerated based on the speed V acquired by the vehicle speed sensor 22 to determine whether or not to shift from the state in which the rotation speed Sp of the pump 16 decreases to the state in which the rotation speed Sp increases. Judgment is made based on whether or not the vehicle shifts to the accelerated state. The control device 28 monitors the transition of the vehicle speed V detected by the vehicle speed sensor 22 and determines whether or not the traveling state of the vehicle has changed from the deceleration state to the acceleration state (S110). In the present embodiment, the determination in step S110 is performed when the vehicle speed V detected by the vehicle speed sensor 22 in a preset section or time gradually decreases and the vehicle speed V does not fall below the preset vehicle speed V1. It is determined that the traveling state of the vehicle has changed from the decelerated state to the accelerated state, and in other cases, it is determined that the traveling state of the vehicle has not changed from the decelerated state to the accelerated state.

When it is determined that the traveling state of the vehicle has changed from the deceleration state to the acceleration state (S110: YES), the control device 28 drives the heater 29 to control the working fluid W to be heated (S120). At this time, the energization amount of the heater 29 is adjusted by feedforward control in which the difference ΔT obtained by subtracting the actual superheat degree Hw from the target superheat degree Hwm is set to zero. In the feedforward control, when the difference ΔT becomes zero and the amount of energization becomes zero, the heating of the working fluid W by the heater 29 is stopped, but if the control is not stopped, the difference ΔT occurs again. Heating to the working fluid W is resumed.

Next, in the control device 28, the actual superheat degree Hw based on the values acquired by the working fluid temperature sensor 25 and the working fluid pressure sensor 26 is the target superheat degree Hwm based on the values acquired by the exhaust temperature sensor 23 and the exhaust flow rate sensor 24. It is determined whether or not it is less than (S130).

When it is determined that the actual superheat degree Hw is equal to or higher than the target superheat degree Hwm (S130: NO), the control device 28 stops driving the heater 29 (S140). Further, when it is determined that the traveling state of the vehicle does not shift from the deceleration state to the acceleration state (S110: NO), the control device 28 does not drive the heater 29.

As described above, the Rankine cycle system 1 of the vehicle controls to heat the working fluid W by driving the heater 29 when it is determined that the rotation speed Sp of the pump 16 shifts from the decreasing state to the increasing state. Therefore, according to the Rankine cycle system 1, even if the amount of heat received per unit flow rate of the working fluid W in the evaporator 17 decreases due to the rapid increase in the rotation speed Sp of the pump 16, it is before flowing into the expander 18. The working fluid W is heated by the heater 29 in the flow path 15, and the liquefaction of the working fluid W is suppressed. This is advantageous for securing the amount of energy of the working fluid W that rotationally drives the expander 18, and it is possible to avoid the stall of the expander 18. As a result, it is possible to avoid a situation in which waste heat cannot be recovered until the expander 18 can regenerate and output again after the expansion machine 18 is stalled, and the chance of waste heat recovery can be increased. In the present disclosure, stall indicates a situation in which the regenerative output of the inflator 18 is reduced or a situation in which the regenerative output is not possible.

Further, the Rankine cycle system 1 of the vehicle determines whether or not the rotation speed Sp of the pump 16 shifts from a decreasing state to an increasing state depending on whether or not the traveling state of the vehicle shifts from the decelerating state to the accelerating state. judge. Therefore, the heater 29 is in a state where the working fluid W can be sufficiently heated by the time the flow rate of the working fluid W changes due to the change in the rotation speed Sp of the pump 16 due to the change in the traveling state of the vehicle. This makes it possible to avoid a delay in the response to heating of the working fluid W by the heater 29.

As illustrated in FIG. 3, a vehicle equipped with the Rankine cycle system 1 of the first embodiment and a vehicle not equipped with the Rankine cycle system 1 are compared. The dotted line portion in FIG. 3 shows the state of the vehicle not equipped with the Rankine cycle system 1 of the present embodiment.

During the period from time t1 to t2, the vehicle decelerates and the load of the engine 2 becomes low. Therefore, the exhaust temperature Tg and the exhaust flow rate Vg are lowered, the target rotation speed Spm is lowered, and the rotation speed Sp of the pump 16 is lowered. At this time, the amount of heat received per unit flow rate of the working fluid W that exchanges heat with the evaporator 17 is reduced due to the decrease in the flow rate due to the decrease in the rotation speed Sp of the pump 16 and the decrease in the exhaust temperature Tg, and the working fluid W is used. The degree of overheating Hw is reduced. Due to this decrease in the degree of superheat Hw, the regenerative output Rp of the expander 18 decreases.

In a vehicle not equipped with the Rankine cycle system 1, as shown by the dotted line portion, when the vehicle shifts from the deceleration state to the acceleration state at time t2, the exhaust flow rate Vg rises sharply and the exhaust temperature Tg also gradually rises. By increasing these two parameters, the target rotation speed Spm becomes higher, and the rotation speed Sp of the pump 16 becomes higher. At this time, the amount of heat received per unit flow rate of the working fluid W in the evaporator 17 is increased due to the increase in the flow rate V of the working fluid W passing through the evaporator 17 due to the increase in the rotation speed Sp of the pump 16. descend. Due to this decrease in the amount of heat received, the degree of superheat Hw of the working fluid W flowing into the expander 18 is reduced to a certain extent that the working fluid W may be liquefied. In such a state, the amount of energy of the working fluid W that rotates the expander 18 is low, and the expander 18 may stall. If such a situation occurs, it will take some time for the regenerative output of the expander 18 to stabilize, and during that time, the regenerative output cannot be taken out from the expander 18. The period from time t2 to t3 shown by the dotted line in FIG. 3 is the period during which the expander 18 stalls and its regenerative output Rpc becomes zero.

As shown by the solid line, the vehicle equipped with the Rankine cycle system 1 heats the working fluid W by the heater 29, so that the superheat degree Hw of the working fluid W flowing into the expander 18 between the times t2 and t3 is the target. It is equivalent to the superheat degree Hwm or higher than the target superheat degree Hwm.

In this way, in the vehicle equipped with the Rankine cycle system 1, the liquefaction of the working fluid W flowing into the expander 18 is suppressed by the heating of the heater 29, so that the stall of the expander 18 is suppressed in the period from time t2 to t3. Will be done. Therefore, the regenerative output Rp can be obtained by driving the expander 18 during the period from time t2 to t3. Further, since the regenerative output Rp of the expander 18 rises to the target value earlier than the conventional one and becomes stable after the time t3, the regenerative output amount by driving the expander 18 can be increased in this respect as well.

When the vehicle speed V when the vehicle is in the decelerated state is slower than the set speed V1, the superheat degree Hw becomes much lower than the target superheat degree Hwm, and the expander 18 is in a stall state before the vehicle is in the accelerated state. Become. Even in such a state, the expander 18 can be operated by driving the heater 29, but the heater 29 is driven until the superheat degree Hw becomes the target superheat degree Hwm or more. Therefore, when the vehicle speed V when the vehicle is in the deceleration state is slower than the set vehicle speed V1, it is desirable to perform a comparison determination between the speed V and the set vehicle speed V1 in determining the deceleration state so as not to drive the heater 29. This makes it possible to operate the expander 18 by driving the heater 29, but it is advantageous to avoid a situation in which the amount of power consumption increases and the fuel consumption deteriorates.

The amount of energization of the heater 29 was adjusted by feed-forward control with the disturbance as the degree of overheating Hw, but the working fluid temperature sensor was placed between the heater 29 and the expander 18 separately from the working fluid temperature sensor 25 and the working fluid pressure sensor 26. If a working fluid pressure sensor is arranged, it is possible to perform feedback control using the value acquired by those sensors as a target value.

The Rankine cycle system 1 of the vehicle of the second embodiment will be described later using the point that the running state acquisition device of the vehicle is not the vehicle speed sensor 22 but the information acquisition device 27 with respect to the first embodiment, and the information acquisition device 27 is used. It differs from the first embodiment in that the pump 16 and the heater 29 are controlled. The second embodiment is otherwise the same as the first embodiment.

The control device 28 predicts a point A at which the operating state of the vehicle shifts from the decelerated state to the accelerated state based on the travel route information acquired by the information acquisition device 27, and the operating state of the vehicle in front of the point A is the decelerated state. The control for maintaining the superheat degree Hw in the deceleration section B and the control for driving the heater 29 near the end of the deceleration section B are performed.

As illustrated in FIG. 6, the time when the vehicle reaches the point A is defined as the time t2. The deceleration section B is a section in which the vehicle travels between times t1 and t2, and is time t1 when the vehicle enters the deceleration section B. The time t2 is when the traveling state of the vehicle is predicted to shift from the deceleration state to the acceleration state, and the time is t4 before the predicted shift to the end of the deceleration section B. Time t4 is a time between time t1 and time t2.

The point A is a point where the driving state of the vehicle changes from the decelerating state to the accelerating state, and a point at the boundary between the downhill road and the uphill road is exemplified. The control device 28 predicts the point A from the travel route information including at least the road surface gradient in the travel route to be traveled acquired by the information acquisition device 27 and the section where the road surface gradient continues. The time for the vehicle to reach the point A may be predicted instead of the point A.

The deceleration section B is a section before the point A, in which the operating state of the vehicle is maintained in the deceleration state, the exhaust temperature Tg and the exhaust flow rate Vg each decrease, and the superheat degree Hw decreases. .. As the deceleration section B, a section from the apex of the downhill road to the point A is exemplified.

The control for maintaining the superheat degree Hw in the deceleration section B is a control performed when the vehicle enters the deceleration section B. This maintenance control first controls to reduce the rotation speed Sp of the pump 16, and then controls to drive the heater 29. The control for lowering is the control for adjusting the rotation speed Sp of the pump 16 by setting the target rotation speed Spm obtained by the control for adjusting the rotation speed Sp of the pump 16 to the correction target rotation speed Spm · k3 of the lower rotation speed. Is.

The correction target rotation speed Spm · k3 is calculated by multiplying the target rotation speed Spm by a preset correction coefficient k3. The correction coefficient k3 is set to a value of 0 or more and less than 1. The correction coefficient k3 can be appropriately set according to the state of the traveling route, and may be set according to the section length of the deceleration section B or the deceleration of the vehicle in the deceleration section B. The correction coefficient k3 may be configured such that its value gradually decreases so that the actual superheat degree Hw becomes equal to or higher than the target superheat degree Hwm.

In the control to drive the heater 29 in the control to maintain, the actual superheat degree Hw is the target superheat even if the rotation speed Sp of the pump 16 is adjusted by the correction target rotation speed Spm · k3 in the control to lower the rotation speed Sp of the pump 16. It is performed when the rotation speed is lower than Hwm.

Further, the control for driving the heater 29 predicts the vehicle speed Vc reaching from the point C where the heater 29 is driven to the point A, and prohibits the driving of the heater 29 when the predicted vehicle speed Vc is lower than the set vehicle speed V1. do. That is, when it is predicted that the actual superheat degree Hw is lower than the target superheat degree Hwm and the expander 18 stalls, the driving of the heater 29 is prohibited. This prohibition of driving the heater 29 is also applied to the control of driving the heater 29 near the end of the deceleration section B.

The control for driving the heater 29 near the end of the deceleration section B is a control for driving the heater 29 before the vehicle reaches the point A and enters the acceleration state. In the present disclosure, the time near the end of the deceleration section B is longer than the time required for the vehicle to reach the point A from the start of driving of the heater 29 until the output of the heater 29 can heat the working fluid W. It is a place that is close to point A within the range of delay. The time required for the heater 29 is a preset fixed value. By the time the control for driving the heater 29 is reached, it is determined whether or not the vehicle speed Vc predicted in the maintenance control is lower than the set vehicle speed V1. Therefore, in the control to be maintained, when it is determined that the vehicle speed Vc predicted to reach the point A is lower than the set vehicle speed V1 and the driving of the heater 29 is prohibited, this control is also prohibited.

As illustrated in FIGS. 7 and 8, the control method of the Rankine cycle system 1 of the vehicle of the second embodiment is repeated at predetermined cycles while the vehicle is running. The predetermined cycle is a cycle in which the information acquisition device 27 updates the travel route on which the vehicle is scheduled to travel.

When the control flow of FIG. 7 starts, the control device 28 predicts the point A based on the travel route information acquired by the information acquisition device 27 (S210). In the present embodiment, the point A is a case where the deceleration section B in which the operating state of the vehicle is maintained in the decelerated state from the travel route information and the exhaust temperature Tg and the exhaust flow rate Vg each decrease is continuous with the uphill road. It is predicted as the end point of the deceleration section B.

Next, the control device 28 determines whether or not the vehicle enters the deceleration section B (S220). The determination in step S220 is that the traveling position of the vehicle is acquired by the antenna of the global positioning satellite system built in the information acquisition device 27, and the vehicle has entered the deceleration section B when the traveling position exists in the deceleration section B. judge.

When it is determined that the vehicle has entered the deceleration section B (S220: YES), the control device 28 performs maintenance control. On the other hand, if it is determined that the vehicle has not entered the deceleration section B (S220: NO), the control device 28 does not perform maintenance control.

When the maintenance control is started, the control device 28 corrects the target rotation speed Spm of the pump 16 to the correction target rotation speed Spm · k3, and adjusts the rotation speed Sp of the pump 16 to the correction target rotation speed Spm · k3 (S230). ). Next, in the control device 28, the actual superheat degree Hw based on the values acquired by the working fluid temperature sensor 25 and the working fluid pressure sensor 26 is the target superheat degree Hwm based on the values acquired by the exhaust temperature sensor 23 and the exhaust flow rate sensor 24. It is determined whether or not it is less than (S240).

When it is determined that the actual superheat degree Hw is equal to or higher than the target superheat degree Hwm (S240: NO), the control device 28 maintains the adjustment of the rotation speed Sp of the pump 16. On the other hand, when it is determined that the actual superheat degree Hw is lower than the target superheat degree Hwm (S240: YES), the control device 28 predicts the vehicle speed Vc to reach the point A (S250). This vehicle speed Vc is predicted according to the distance to the point A, the current vehicle speed V, and the deceleration in the decelerated state. Next, the control device 28 determines whether or not the predicted vehicle speed Vc is lower than the set vehicle speed V1 (S260).

When it is determined that the predicted vehicle speed Vc is equal to or higher than the set vehicle speed V1 (S260: NO), the control device 28 drives the heater 29 to control the working fluid W to be heated (S270). On the other hand, when it is determined that the predicted vehicle speed Vc is lower than the set vehicle speed V1 (S260: YES), the control device 28 prohibits the driving of the heater 29 (S280).

When the control flow of FIG. 8 starts, the control device 28 predicts the point A based on the travel route information acquired by the information acquisition device 27 (S310). Next, the control device 28 determines whether or not the traveling position of the vehicle is near the end of the deceleration section B (S320). In this step S320, the time predicted to reach the point A from the traveling position of the vehicle at the time of determination is longer than the time required for the output of the heater 29 to be able to heat the working fluid W after the start of driving the heater 29. The place closest to the point A in the slow range is the vicinity of the end of the deceleration section B. Further, in this step S320, when the traveling position of the vehicle reaches the vicinity of the end thereof, it is determined that the traveling position of the vehicle is near the end of the deceleration section B.

When it is determined that the traveling position of the vehicle is near the end of the deceleration section B (S320: YES), the control device 28 determines whether or not the driving of the heater 29 is prohibited in the control to be maintained (S330). The determination in step S330 determines whether or not step S280 has been performed.

When it is determined that the driving of the heater 29 is not prohibited (S330: NO), the control device 28 drives the heater 29 to control the working fluid W to be heated (S340).

Next, in the control device 28, the actual superheat degree Hw based on the values acquired by the working fluid temperature sensor 25 and the working fluid pressure sensor 26 is the target superheat degree Hwm based on the values acquired by the exhaust temperature sensor 23 and the exhaust flow rate sensor 24. It is determined whether or not it is less than (S350).

When it is determined that the actual superheat degree Hw is equal to or higher than the target superheat degree Hwm (S350: NO), the control device 28 stops driving the heater 29 (S360). On the other hand, when it is determined that the actual superheat degree Hw is lower than the target superheat degree Hwm (S350: NO), the control device 28 maintains the drive of the heater 29.

Further, when it is determined that the traveling position of the vehicle is not near the end of the deceleration section B (S320: NO) or it is determined that the driving of the heater 29 is prohibited (S330: YES), the control device 28 determines that the heater 29 Do not drive.

As described above, the Rankine cycle system 1 of the vehicle of the second embodiment predicts the deceleration section B in which the traveling state of the vehicle becomes the deceleration state, and when the vehicle enters the deceleration section B, the target rotation speed Spm is set. The rotation speed Sp of the pump 16 is adjusted based on the correction target rotation speed Spm · k3, which is a lower rotation speed. Therefore, according to the Rankine cycle system 1, the flow rate of the working fluid W is reduced in the deceleration section B of the vehicle to maintain the amount of heat received per unit flow rate of the working fluid W in the evaporator 17, and the working fluid W is maintained. It is possible to suppress the decrease in the degree of overheating Hw. As a result, even in the section where each of the exhaust temperature Tg and the exhaust flow rate Vg decreases, the period in which the superheat degree Hw becomes the target superheat degree Hwm or more can be extended, and the opportunity for waste heat recovery can be increased.

Further, the Rankine cycle system 1 drives the heater 29 when the superheat degree Hw is lower than the target superheat degree Hwm even if the rotation speed Sp of the pump 16 is adjusted. Therefore, it is possible to avoid a situation in which the superheat degree Hw falls below the target superheat degree Hwm and the expander 18 stalls by the time the vehicle reaches the point A. As a result, even in the section where each of the exhaust temperature Tg and the exhaust flow rate Vg decreases, the period in which the superheat degree Hw becomes the target superheat degree Hwm or more can be extended, and the opportunity for waste heat recovery can be increased.

The drive of the heater 29 when the traveling state of the vehicle is decelerated is performed when the overall fuel efficiency is improved. When the running state of the vehicle is in a decelerated state and the vehicle speed V is lower than the set vehicle speed V1, the time required for the superheat degree Hw of the working fluid W to be equal to or higher than the target superheat degree Hwm even if the heater 29 is driven. Becomes longer. Even if the heater 29 is driven to heat the working fluid W to operate the expander 18 in such a situation, the amount of electric power consumed by the heater 29 increases, and the overall fuel consumption deteriorates. Therefore, prohibiting the driving of the heater 29 in such a situation is advantageous for improving the overall fuel efficiency.

Further, the Rankine cycle system 1 of the vehicle controls to heat the working fluid W by driving the heater 29 before the transition to the acceleration state when the traveling state of the vehicle is predicted to shift from the deceleration state to the acceleration state. I do. Therefore, according to the Rankine cycle system 1, even if the amount of heat received per unit flow rate of the working fluid W in the evaporator 17 decreases due to the rapid increase in the rotation speed Sp of the pump 16, it is before flowing into the expander 18. The working fluid W is heated by the heater 29 in the flow path 15, and the liquefaction of the working fluid W is suppressed. This is advantageous for securing the amount of energy of the working fluid W that rotationally drives the expander 18, and it is possible to avoid the stall of the expander 18. As a result, it is possible to avoid a situation in which waste heat cannot be recovered until the expander 18 can regenerate and output again after the expansion machine 18 is stalled, and the chance of waste heat recovery can be increased.

Further, the Rankine cycle system 1 of the vehicle starts driving the heater 29 earlier than in the first embodiment, avoids a delay in the heating response of the working fluid W by the heater 29, and raises the temperature of the working fluid W at an early stage. There is also the advantage of being able to do it.

The control for lowering the rotation speed Sp of the pump 16 of the second embodiment has been described by taking as an example the control of setting the target rotation speed Spm to the correction target rotation speed Spm · k3, but the target superheat degree obtained by the target superheat degree map 28a has been described. Hwm may be multiplied by a correction factor to reduce the rotation speed Sp of the pump 16 using a correction target superheat degree lower than the target superheat degree Hwm.

As illustrated in FIG. 6, a vehicle equipped with the Rankine cycle system 1 of the second embodiment and a vehicle not equipped with the Rankine cycle system 1 are compared. The dotted line portion in FIG. 6 shows the state of the vehicle not equipped with the Rankine cycle system 1 of the present embodiment. The deceleration section B is a section in which the vehicle travels between times t1 and t2, and is time t1 when the vehicle enters the deceleration section B.

In the vehicle not equipped with the Rankine cycle system 1 of the second embodiment, the rotation speed of the pump 16 is Sp1 (dotted line portion) between the times t1 and t2, whereas the Rankine cycle system of the second embodiment is used. In the vehicle equipped with 1, the rotation speed of the pump 16 has dropped to Sp2 (solid line portion).

During the period from time t1 to t2, the amount of heat received per unit flow rate of the working fluid W that exchanges heat with the evaporator 17 decreases. By reducing the rotation speed of the pump 16 as described above during this period, the flow rate of the working fluid W passing through the evaporator 17 is reduced, so that the flow rate of the working fluid W that exchanges heat with the evaporator 17 is per unit flow rate. The amount of heat received increases. Therefore, the temperature Tw and the superheat degree Hw of the working fluid W flowing into the expander 18 are higher than the temperature Twc and the superheat degree Hwc when the flow rate of the pump 16 is not reduced.

The vehicle equipped with the Rankine cycle system 1 of the second embodiment starts energizing the heater 29 at a time t4 before the time t2. The time t4 is also the time when the superheat degree is lower than the target superheat degree Hwm only by lowering the rotation speed Sp of the pump 16.

By heating the working fluid W by the heater 29 during the period from time t4 to t3, the temperature Tw (solid line portion) of the working fluid W flowing into the expander 18 is the temperature Twc (dotted line) when the heater 29 does not heat the working fluid W. Part) will be higher. Further, the superheat degree Hw (solid line portion) of the working fluid W flowing into the expander 18 is larger than the superheat degree Hwc (dotted line portion) when the heater 29 does not heat the working fluid W. Therefore, it is possible to suppress the liquefaction of the working fluid W flowing into the expander 18 when the vehicle shifts from the deceleration state to the acceleration state. Therefore, it is possible to increase the chances of recovering waste heat by avoiding a decrease in the regenerative output of the expander 18 and a state in which the regenerative output cannot be performed.

Control is performed to heat the working fluid W by driving the heater 29 before the traveling state of the vehicle shifts from the deceleration state to the acceleration state. Since the heater 29 is driven before the transition to improve the temperature Tw and the superheat degree Hw of the working fluid W, the temperature Tw and the superheat degree Hw cause the liquefaction of the working fluid W at the time of the transition. It is possible to suppress the decrease to the value.

In the above-described embodiment, an example in which the drive of the heater 29 is stopped based on the degree of superheat Hw after the drive of the heater 29 is started is illustrated, but based on the travel route information of the vehicle acquired by the information acquisition device 27. A period t for driving the heater 29 to control the heating of the working fluid W may be predicted, and the driving of the heater 29 may be stopped when the predicted period t exceeds the threshold period ta. When the traveling state of the vehicle is in the accelerating state, the superheat degree Hw has a positive correlation with the section in which the vehicle travels or the period thereof. Therefore, instead of the superheat degree Hw, the drive of the heater 29 may be stopped based on the predicted section or period.

In the above-described embodiment, the condition for starting the driving of the heater 29 is that the vehicle speed V does not fall below the set vehicle speed V1 when the traveling state of the vehicle is in the decelerated state, but the threshold value of the preset electric energy amount is set. And the amount of electric power predicted to be consumed by driving the heater 29 may be compared, and the driving of the heater 29 may be started when the predicted amount of electric power is equal to or less than the threshold value of the amount of electric power. By obtaining the transition of the total electric energy by conditions, tests, or simulations in advance and setting the threshold value of the electric energy based on the transition, it is effective to avoid the situation where the fuel consumption is deteriorated by driving the heater 29. In addition, it is possible to increase opportunities for waste heat recovery.

1 Vehicle Rankine cycle system 2 Engine (internal combustion engine)
4 Exhaust passage 14 Reflux exhaust valve 15 Working fluid flow path 16 Pump 17 Evaporator 18 Inflator 19 Condensator 20 Tank 21 Generator 22 Vehicle speed sensor (parameter acquisition device)
23 Exhaust temperature sensor 24 Exhaust flow rate sensor 25 Working fluid temperature sensor (control value acquisition device)
26 Working fluid pressure sensor 27 Information acquisition device (parameter acquisition device)
28 Control device 28a Rotation speed map 28b Target temperature map 29 Heater

Claims (8)

A flow path of the working fluid in which a pump, an evaporator, an expander, and a condenser are arranged and a control device are provided in the order in which the working fluid flows, and the evaporator is a waste heat fluid and a working fluid of an internal combustion engine. Control that heat is exchanged between the two, and the control device adjusts the rotation speed of the pump to make a positive correlation between the rotation speed of the pump and the flow rate and temperature of the exhaust in the exhaust passage of the internal combustion engine. In the Rankine cycle system of the vehicle
A heater arranged in the flow path between the evaporator and the expander, and a parameter acquisition device for acquiring parameters related to the rotation speed of the pump are provided.
When the control device determines that the pump rotation speed shifts from a decreasing state to an increasing state based on the parameters acquired by the parameter acquisition device, the control device controls to heat the working fluid by driving the heater. A vehicle Rankine cycle system characterized by a configuration to be performed. The parameter acquisition device has a vehicle speed sensor that acquires the speed of the vehicle.
The control device determines whether or not the pump rotation speed shifts from a decreasing state to an increasing state based on the speed acquired by the vehicle speed sensor, and the traveling state of the vehicle shifts from the deceleration state to the acceleration state. Claim 1 is a configuration in which it is determined whether or not the pump is driven, and when it is determined that the traveling state of the vehicle has changed from the deceleration state to the acceleration state, it is determined that the rotation speed of the pump has changed from the decreasing state to the increasing state. The Rankine cycle system of the vehicle described in. The control device controls the heating when the speed in the deceleration state is equal to or higher than a preset vehicle speed, and does not control the heating when the speed in the deceleration state is less than the set vehicle speed. The Rankine cycle system for a vehicle according to claim 2, which is a configuration. The parameter acquisition device has an information acquisition device for acquiring travel route information of the vehicle.
When the control device predicts that the traveling state of the vehicle will shift from the deceleration state to the acceleration state based on the travel route information acquired by the information acquisition device, the deceleration section in which the traveling state of the vehicle becomes the deceleration state. The second or third aspect of the present invention, wherein when the vehicle enters the vehicle, the rotation speed of the pump is controlled to be lower than the rotation speed according to the flow rate and temperature of the exhaust indicated by the positive correlation. The Rankine cycle system of the vehicle. The control device predicts a point or time at which the traveling state of the vehicle shifts from the deceleration state to the acceleration state based on the travel route information acquired by the information acquisition device, and is more than the predicted transition point or time. The Rankine cycle system for a vehicle according to claim 4, which is configured to control the heating in advance. A control value acquisition device for acquiring a control value of at least one of the temperature and the degree of superheat of the working fluid flowing into the expander is provided.
When the control device performs the reduction control, the control value acquired by the control value acquisition device targets at least one of the target temperature and the target superheat degree of the working fluid capable of driving the inflator. The Rankine cycle system for a vehicle according to claim 4 or 5, which is configured to control the heating when the value falls below the value. A control value acquisition device for acquiring a control value of at least one of the temperature and the degree of superheat of the working fluid flowing into the expander is provided.
In the heating control, the control device is a difference obtained by subtracting the control value acquired by the control value acquisition device from the target value of at least one of the target temperature and the target superheat degree of the working fluid that can drive the inflator. The Rankine cycle system for a vehicle according to any one of claims 1 to 6, which is configured to adjust the energization amount of the heater based on the above. A pump, an evaporator, an expander, and a flow path of the working fluid in which a condenser is arranged are provided in the order in which the working fluid flows, and the evaporator causes heat exchange between the waste heat fluid of the internal combustion engine and the working fluid. At the same time, control of the Rankin cycle system of the vehicle that controls the rotation speed of the pump so that the rotation speed of the pump and the flow rate and temperature of the exhaust in the exhaust passage of the internal combustion engine are positively correlated with each other. In the method
The step of sequentially acquiring the parameters related to the rotation speed of the pump, and
A step of determining whether or not the pump rotation speed has changed from a decreasing state to an increasing state, and
When it is determined that the pump rotation speed has changed from a decreasing state to an increasing state, the heater arranged between the evaporator and the inflator is driven to drive the working fluid flowing into the inflator. The step to heat and
A method of controlling a vehicle's Rankine cycle system, characterized in that it has.

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