WO2020189427A1 - Rankine cycle system and manufacturing method for same - Google Patents

Rankine cycle system and manufacturing method for same Download PDF

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Publication number
WO2020189427A1
WO2020189427A1 PCT/JP2020/010420 JP2020010420W WO2020189427A1 WO 2020189427 A1 WO2020189427 A1 WO 2020189427A1 JP 2020010420 W JP2020010420 W JP 2020010420W WO 2020189427 A1 WO2020189427 A1 WO 2020189427A1
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working fluid
flow path
temperature
section
installation position
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PCT/JP2020/010420
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French (fr)
Japanese (ja)
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晃太 加藤
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いすゞ自動車株式会社
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
    • F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
    • F01K25/10—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours the vapours being cold, e.g. ammonia, carbon dioxide, ether

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  • This disclosure relates to the Rankine cycle system and its control method.
  • a vehicle waste heat utilization device for example, a vehicle Rankine cycle system
  • a working fluid that exchanges heat with a heat source fluid that transfers waste heat of an internal combustion engine is expanded by an expander to recover mechanical energy (for example, a vehicle Rankine cycle system). See Patent Document 1).
  • the outlet of the expander is connected to the inlet of the condenser (condenser) via a pipe forming a flow path for a working fluid.
  • the inlet of the condenser may be located higher than the outlet of the expander.
  • the present disclosure is to provide a Rankine cycle system and a control method thereof capable of estimating the amount of condensate stored in the flow path between the outlet of the expander and the inlet of the condenser with high accuracy.
  • the Rankin cycle system of the embodiment of the present disclosure for achieving the above object includes a flow path for circulating a working fluid, an expander arranged in the flow path for expanding the working fluid, and a downstream side of the expander.
  • a Rankin cycle system configured to include a condenser that is arranged in the flow path of the above and whose inlet is arranged higher than the outlet of the inflator to condense the working fluid, the outlet of the inflator.
  • the pressure acquisition device arranged in the first flow path, which is the flow path between the inlet and the inlet of the condenser, and the first flow path are formed in an upward gradient from the expander toward the condenser.
  • the calculation control device includes a plurality of temperature acquisition devices arranged at intervals in the section and a calculation control device that calculates and controls the parameters of the Rankin cycle system, and the calculation control device acquires the pressure acquisition device. Based on the value and the acquired values of the plurality of temperature acquisition devices, the degree of superheat of the working fluid at the installation position of each of the temperature acquisition devices is calculated, and based on the calculated degree of superheat of the working fluid.
  • the installation position and gas state of the temperature acquisition device in which the estimated phase state of the working fluid is a liquid state It is configured to control to estimate that the liquid level of the working fluid in the liquid state stored in the first flow path is in a section at both ends of the installation position of the temperature acquisition device.
  • control method of the Rankin cycle system includes a flow path for circulating a working fluid, an expander arranged in the flow path for expanding the working fluid, and the above.
  • a condenser that is arranged in the flow path on the downstream side of the inflator and whose inlet is arranged at a position higher than the outlet of the inflator to condense the working fluid, and an outlet of the inflator and an inlet of the condenser.
  • the pressure acquisition device acquires the pressure of the working fluid passing through the first flow path and a plurality of pressure acquisition devices.
  • the third step of estimating the phase state of the working fluid at the installation position of each of the temperature acquisition devices, and the third step of the working fluid The above-mentioned stored in the first flow path in a section where the installation position of the temperature acquisition device estimated to be in the liquid state and the installation position of the temperature acquisition device estimated to be in the gas state are both ends. It is a method characterized by having a fourth step of presuming that there is a liquid level of the working fluid in a liquid state.
  • the amount of condensate stored in the flow path between the outlet of the expander and the inlet of the condenser can be estimated with high accuracy.
  • FIG. 1 is a diagram illustrating the Rankine cycle system of the present embodiment.
  • FIG. 2 is an enlarged view of the flow path for the working fluid between the expander and the condenser of FIG.
  • FIG. 3 is a diagram illustrating a control method of the Rankine cycle system of the present embodiment in the form of a control flow.
  • the Rankine cycle system 1 of the present embodiment has a tank 3, a pump (circulator) 4, an evaporator 5, and an expander in a flow path (flow path) 2 for a working fluid. It is a system including 6 and a condenser 7.
  • the flow path 2 for the working fluid is a closed flow path for circulating the working fluid W.
  • the tank 3 is arranged in the flow path 2 for the working fluid and stores the working fluid W.
  • the pump 4 is arranged in the flow path 2 for the working fluid on the downstream side of the tank 3, and the working fluid W is circulated in the flow path 2 for the working fluid by pumping the working fluid W.
  • the evaporator 5 is arranged in the flow path 2 for the working fluid on the downstream side of the pump 4, and heats and evaporates the working fluid W by exchanging heat with the exhaust G of the engine (internal combustion engine).
  • the inflator 6 is arranged in the flow path 2 for the working fluid on the downstream side of the evaporator 5 to expand the working fluid W.
  • a drive device (engine, motor, etc.) is connected to the output shaft 6a of the expander 6 via a disconnection device (clutch, etc.), and is generated in the output shaft 6a due to expansion of the working fluid W when the disconnection device is connected. The generated power is transmitted to the drive device.
  • the condenser 7 is arranged in the flow path 2 for the working fluid on the downstream side of the expander 6 to condense the working fluid W.
  • the inlet 7a of the condenser 7 is located higher than the outlet 6b of the expander 6.
  • the flow path between the outlet 6b of the expander 6 and the inlet 7a of the condenser 7 is referred to as a first flow path 2a.
  • the outlet 7b of the condenser 7 is arranged higher than the inlet 3a of the tank 3.
  • the flow path formed on this uphill slope is referred to as a section 2b.
  • the working fluid (condensate) WL that has transitioned from the gas state to the liquid state in the first flow path 2a is stored.
  • the liquid level LS of the condensate WL increases.
  • the section 2b is configured so that the condensate WL and the working fluid W in the gaseous state can come into contact with each other to such an extent that heat exchange is possible.
  • the section 2b is preferably provided at a position where the condensate WL is relatively likely to be generated, and for example, it is preferably provided in the flow path on the expander 6 side from the central position of the first flow path 2a. Condensate WL is more likely to occur as it approaches the outlet 6b of the expander 6 with respect to the first flow path 2a.
  • the section 2b of the present embodiment is arranged from the lowermost position (position B1) of the flow path extending vertically downward from the outlet 6b of the inflator 6 to the inlet 7a side of the condenser 7 from this lowermost position. It is an uphill flow path formed up to a position (position B5) higher than the outlet 6b of the expander 6 and lower than the inlet 7a of the condenser 7.
  • the condensate WL is stored in the flow path and section 2b from the outlet 6b of the expander 6 to the position B1.
  • the liquid level LS of the condensate WL in the section 2b increases upward with the position B1 as the lowest position.
  • the liquid level of the condensate WL in the flow path from the outlet 6b to the position B1 of the expander 6 also rises while maintaining the same height position as the liquid level LS of the condensate WL in the section 2b.
  • a pressure sensor (pressure acquisition device) 8 for acquiring the pressure of the working fluid W passing through the first flow path 2a is arranged in the first flow path 2a. Since the pressure of the working fluid W hardly changes in the first flow path 2a, the position of the pressure sensor 8 may be any position in the first flow path 2a where there is no possibility that the condensate WL is generated. In the present embodiment, the pressure sensor 8 is arranged at the position A1 in the first flow path 2a on the inlet 7a side of the condenser 7 from the section 2b.
  • a plurality of (five in this embodiment) temperature sensors (temperature acquisition devices) 9 (9a to 9e) are arranged in the section 2b of the first flow path 2a at intervals of each.
  • the temperature sensor 9a is located at position B1, the temperature sensor 9b is located at position B2, the temperature sensor 9c is located at position B3, the temperature sensor 9d is located at position B4, and the temperature sensor 9e is located at position B5.
  • At least one temperature sensor 9 may be arranged at a position where the condensate WL may be stored, and at least one may be arranged at a position where the condensate WL may not be stored, and the number of the temperature sensors 9 installed is not particularly limited. ..
  • Positions B1, B2, and B3 are set lower than the outlet 6b of the inflator 6. Even if there is a liquid level LS of the condensate WL at these positions B1 to B3, the condensate WL flows back into the expander 6 and does not flow in.
  • the positions B4 and B5 are set higher than the outlet 6b of the inflator 6. If there is a liquid level LS of the condensate WL at these positions B4 and B5, the condensate WL flows back into the expander 6 and flows into the expander 6.
  • Positions B1, B2, B3, B4, and B5 are located closer to the outlet 6b of the expander 6 (farther from the inlet 7a of the condenser 7) and lower.
  • the Rankine cycle system 1 of the present embodiment is provided with a calculation control device 10 that calculates and controls the parameters of the Rankine cycle system 1 (such as the degree of superheat of the working fluid W and the liquid level).
  • the arithmetic control device 10 is a 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 various information processing, and various interfaces. It is wear.
  • Various devices such as a pressure sensor 8, a temperature sensor 9, and a pump 4 are electrically connected to the arithmetic control device 10.
  • the arithmetic control device 10 is based on the acquired value P of the pressure sensor 8 and the acquired value T (Ta, Tb, Tc, Td, Te) of the plurality of temperature sensors 9, respectively.
  • the degree of superheat of the working fluid W at the installation positions B1 to B5 of the temperature sensor 9 is calculated.
  • the degree of superheat is the difference between the temperature of the working fluid W and the saturation temperature, which are in a superheated state higher than the saturation temperature of the working fluid W.
  • the arithmetic control device 10 estimates the phase state (gas state or liquid state) of the working fluid W at the installation positions B1 to B5 of each temperature sensor 9 based on the calculated superheat degree of the working fluid W.
  • the acquisition value T of the temperature sensor 9 is equal to or higher than the preset set temperature T1 of the arithmetic control device 10
  • the phase state of the working fluid W at the installation position of the temperature sensor 9 is in the gaseous state. If it is determined to be present and the temperature is lower than the set temperature T1, it is estimated to be in a liquid state.
  • the set temperature T1 is a value that changes according to the pressure P of the working fluid W, and is preset by experiments or the like as an index that can estimate that the phase state of the working fluid W is either a gas state or a liquid state. The temperature.
  • the arithmetic control device 10 has a position because the temperature Ta of the working fluid W at the position B1, the temperature Tb of the working fluid W at the position B2, and the temperature Tc of the working fluid W at the position B3 are less than the set temperature T1. It is estimated that the working fluid W in B1 to B3 is in a liquid state. On the other hand, in the arithmetic control device 10, since the temperature Td of the working fluid W at the position B4 and the temperature Te of the working fluid W at the position B5 are equal to or higher than the set temperature T1, the working fluid W at the positions B4 and B5 is in a gaseous state. Presumed to be.
  • the arithmetic control device 10 is connected to the first flow path 2a in a section where the installation position of the temperature sensor 9 in which the estimated phase state of the working fluid W is in the liquid state and the installation position of the temperature sensor 9 in the gas state are both ends. It is configured to control the estimation that the liquid level LS of the stored condensate WL is present.
  • the sections at both ends are the installation position B3 of the temperature sensor 9c in which the phase state of the working fluid W is in the liquid state and the installation position B4 of the temperature sensor 9d in which the phase state of the working fluid W is in the gas state. It is a section between.
  • the section (the section between the position B3 and the position B4) where the liquid level LS of the condensate WL is located is a part of the section 2b and is located above the preset section set in advance by an experiment or the like.
  • the output of the pump 4 is controlled to be reduced so that the flow rate of the working fluid W passing through the flow path 2 for the working fluid is reduced from the flow rate at the time of normal control.
  • the control for reducing the output of the pump 4 is performed regardless of the operating state of the engine.
  • the set section is a section set so that the condensate WL does not flow back into the expander 6 as long as there is a liquid level LS of the condensate WL in this section.
  • the set section is a section between positions B1 to B3.
  • the flow rate of the working fluid W during normal control of the pump 4 is set based on the temperature and flow rate of the exhaust gas G passing through the evaporator 5.
  • the temperature T of the working fluid W passing through the above is raised to the set temperature T1 or higher.
  • the set temperature T1 is a temperature preset by an experiment or the like as a temperature at which the condensate WL stored in the first flow path 2a can be evaporated.
  • the working fluid W having a temperature T equal to or higher than the set temperature T1 is the first flow.
  • the condensate WL stored in the first flow path 2a exchanges heat with the working fluid W in a gaseous state and evaporates.
  • Control to reduce the output of the pump 4 is performed at least until the liquid level LS of the condensate WL falls within the set section.
  • the control for reducing the output of the pump 4 is performed until the liquid level LS of the condensate WL falls within the section of positions B1 to B3.
  • the arithmetic control device 10 controls the reduction of the output of the pump 4, and the phase state of the working fluid W at the measurement positions of the temperatures of all the working fluids W (B1 to B5 in this embodiment) is the gas state. It may be configured to carry out until it is determined. In this case, since the condensed liquid WL stored in the first flow path 2a is almost absent, it is possible to significantly suppress a decrease in the output of the expander 6 due to the backflow of the condensed liquid WL.
  • the arithmetic control device 10 estimates that the liquid level LS of the condensate WL is in the section between positions B4 to B5, the condensate WL flows back into the expander 6 and flows into the expander 6, and the output of the expander 6 is output. Is decreasing.
  • the arithmetic control device 10 further controls the temperature of the working fluid W by controlling the output of the pump 4 to be further lowered as compared with the case where the liquid level LS of the condensate WL is in the section of positions B3 to B4. It is preferable to raise the temperature. By doing so, the evaporation of the condensate WL is further promoted, so that the output decrease of the expander 6 can be suppressed.
  • the control flow based on the Rankine cycle system 1 of the present embodiment in other words, the control method of the Rankine cycle system will be described with reference to FIG. 3 in the form of an example of the control flow.
  • the control flow shown in FIG. 3 is a control flow that is periodically performed when the engine is in an operating state.
  • step S10 the pressure sensor 8 acquires the pressure P of the working fluid W passing through the first flow path 2a, and the plurality of temperature sensors 9 obtain the pressure P.
  • the temperature T of the working fluid W passing through the first flow path 2a at each of the installation positions B1 to B5 is acquired.
  • step S20 the arithmetic control device 10 determines the pressure P of the working fluid W acquired in step S10 and the temperature T of the working fluid W at the respective installation positions B1 to B5 of the plurality of temperature sensors 9. Based on the above, the degree of superheat of the working fluid W at the installation positions B1 to B5 of each temperature sensor 9 is calculated. After performing step S20, step S30 is carried out.
  • step S30 the arithmetic control device 10 estimates the phase state of the working fluid W at the installation positions B1 to B5 of each temperature sensor 9 based on the degree of superheat calculated in step S20. After performing step S30, the process proceeds to step S40.
  • step S40 the arithmetic control device 10 estimates that the phase state of the working fluid W is the installation position B3 of the temperature sensor 9 estimated to be in the liquid state and the temperature sensor estimated to be in the gas state in step S30. It is presumed that the liquid level LS of the condensate WL stored in the first flow path 2a is in the section where the installation position B4 of 9 is at both ends. After performing step S40, the process proceeds to step S50.
  • step S50 the arithmetic control device 10 determines whether or not the section with the liquid level LS of the condensate WL estimated in step S40 is located above the set section (first section determination). When the section where the liquid level LS of the condensate WL is located is located above the set section (S50: YES), the process proceeds to step S60. If the section where the liquid level LS of the condensate WL is located is not located above the set section (S50: NO), the process proceeds to step S70.
  • step S60 the arithmetic control device 10 controls to reduce the output of the pump 4 so that the flow rate of the working fluid W passing through the first flow path 2a is reduced from the flow rate at the time of normal control.
  • the temperature T of the working fluid W passing through the first flow path 2a is raised to a set temperature T1 or higher, and the condensate WL stored in the first flow path 2a is evaporated.
  • step S70 the arithmetic control device 10 determines whether or not the output of the pump 4 is lower than the output during normal control. In other words, it is determined whether or not the step S60 has been passed. If the output of the pump 4 is lower than the output during normal control (S70: YES), the process proceeds to step S80. If the output of the pump 4 is not lower than the output during normal control (S70: NO), the process proceeds to return and the present control flow is terminated.
  • step S80 in the arithmetic control device 10, is the section in which the liquid level LS of the condensate WL estimated in step S40 is located in the second set section preset as a part of the set section and relatively lower section? Judgment whether or not (second section judgment).
  • the second set section the time from the end of the control for reducing the output of the pump 4 to the start of the control for reducing the output of the next pump 4 is set to a time that does not affect the durability of the pump 4. It is a possible section.
  • the second set section is a section between the position B1 and the position B2.
  • step S90 If the section where the liquid level LS of the condensate WL is located is in the second set section (S80: YES), the process proceeds to step S90. If the section where the liquid level LS of the condensate WL is present is not in the second set section (S80: NO), the process returns to step S10.
  • step S80 may be substituted by determining whether or not the phase state of the working fluid W at the measurement positions of the temperatures of all the working fluids W (B1 to B5 in this embodiment) has become a gas state. .. If the phase state of the working fluid W at the measurement position of the temperature of all the working fluid W is a gas state (S80: YES), the process proceeds to step S90. If there is a temperature measurement position where the phase state of the working fluid W is not the gaseous state (S80: NO), the process returns to step S10.
  • step S90 the arithmetic control device 10 returns the output of the pump 4 to the output during normal control. After executing step S90, the process proceeds to return and the present control flow is terminated.
  • the amount of condensate WL stored in the first flow path 2a between the outlet 6b of the expander 6 and the inlet 7a of the condenser 7 is determined. It can be estimated with high accuracy.
  • the present invention has the effect of being able to estimate the amount of condensate stored in the flow path between the outlet of the expander and the inlet of the condenser with high accuracy, and is used in the Rankine cycle system and its control method. It is useful.

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  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
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Abstract

The present invention is provided with: a pressure sensor 8 disposed in a first passage 2a between an outlet 6b of an expander 6 and an inlet 7a of a condenser 7; and a plurality of temperature sensors 9 disposed apart from each other in a section with an ascending slope from the expander 6 towards the condenser 7 with respect to the first passage 2a. According to the present invention, the degree of overheating of a working fluid is calculated at the installation positions of the respective temperature sensors 9 on the basis of an acquisition value P of the pressure sensor 8 and an acquisition value T of the temperature sensors 9, the phase state of the working fluid W is estimated at the installation positions of the respective temperature sensors 9 on the basis of the calculated degree of overheating, and it is estimated that there is a liquid surface on the condensate stored in the first passage 2a in a section having, as both ends, the installation position of a temperature sensor 9 for which the estimated phase state of the working fluid W is a liquid state and the installation position of a temperature sensor 9 for which the estimated phase state is a gas state.

Description

ランキンサイクルシステム及びその制御方法Rankine cycle system and its control method
　本開示は、ランキンサイクルシステム及びその制御方法に関する。 This disclosure relates to the Rankine cycle system and its control method.
　内燃機関の廃熱を移送する熱源流体と熱交換した作動流体を膨張器により膨張させて機械的エネルギーを回収する車両用廃熱利用装置（車両のランキンサイクルシステム）が提案されている（例えば、特許文献１参照）。 A vehicle waste heat utilization device (for example, a vehicle Rankine cycle system) has been proposed in which a working fluid that exchanges heat with a heat source fluid that transfers waste heat of an internal combustion engine is expanded by an expander to recover mechanical energy (for example, a vehicle Rankine cycle system). See Patent Document 1).
日本国特開２０１４―１６９６７３号公報Japanese Patent Application Laid-Open No. 2014-169673
　ところで、車両のランキンサイクルシステムでは、膨張器（タービン）の出口が作動流体用の流路を構成する配管を介して凝縮器（コンデンサ）の入口に接続されているが、設置レイアウトの関係上、凝縮器の入口が膨張器の出口より高い位置に配置される場合がある。 By the way, in the Rankine cycle system of a vehicle, the outlet of the expander (turbine) is connected to the inlet of the condenser (condenser) via a pipe forming a flow path for a working fluid. However, due to the installation layout, The inlet of the condenser may be located higher than the outlet of the expander.
　この場合、凝縮器の入口と膨張器の出口を接続する配管で液体状態となった作動流体（凝縮液）が重力により膨張器側に逆流して膨張器の出力を低下させる虞がある。したがって、この配管内に貯留された凝縮液の量によっては凝縮液を処理する制御を行う必要があるが、そのためには先ずこの貯留された凝縮液の量を推定する必要がある。 In this case, there is a risk that the working fluid (condensate) that has become liquid in the piping connecting the inlet of the condenser and the outlet of the expander will flow back to the expander side due to gravity and reduce the output of the expander. Therefore, it is necessary to control the processing of the condensate depending on the amount of the condensate stored in the pipe, but for that purpose, it is first necessary to estimate the amount of the stored condensate.
　本開示は、膨張器の出口と凝縮器の入口の間の流路に貯留される凝縮液の量を高精度で推定することができるランキンサイクルシステム及びその制御方法を提供することにある。 The present disclosure is to provide a Rankine cycle system and a control method thereof capable of estimating the amount of condensate stored in the flow path between the outlet of the expander and the inlet of the condenser with high accuracy.
　上記の目的を達成するための本開示の態様のランキンサイクルシステムは、作動流体を循環させる流路と、前記流路に配置されて前記作動流体を膨張させる膨張器と、前記膨張器より下流側の前記流路に配置されるとともにその入口が前記膨張器の出口より高い位置に配置されて前記作動流体を凝縮させる凝縮器と、を備えて構成されるランキンサイクルシステムにおいて、前記膨張器の出口と前記凝縮器の入口の間の前記流路である第１流路に配置された圧力取得装置と、前記第１流路に関して、前記膨張器から前記凝縮器に向かって上り勾配に形成された区間に各々の間隔をあけて複数配置された温度取得装置と、前記ランキンサイクルシステムのパラメータを演算し、制御する演算制御装置と、を備えて、前記演算制御装置が、前記圧力取得装置の取得値と複数の前記温度取得装置の取得値とに基づいて、各々の前記温度取得装置の設置位置での前記作動流体の過熱度を算出して、この算出した前記作動流体の前記過熱度に基づいて各々の前記温度取得装置の前記設置位置での前記作動流体の相状態を推定するとともに、この推定した前記作動流体の前記相状態が液体状態である前記温度取得装置の設置位置と気体状態である前記温度取得装置の設置位置とが両端となる区間に前記第１流路に貯留された前記液体状態の前記作動流体の液面があると推定する制御を行うように構成される。 The Rankin cycle system of the embodiment of the present disclosure for achieving the above object includes a flow path for circulating a working fluid, an expander arranged in the flow path for expanding the working fluid, and a downstream side of the expander. In a Rankin cycle system configured to include a condenser that is arranged in the flow path of the above and whose inlet is arranged higher than the outlet of the inflator to condense the working fluid, the outlet of the inflator. The pressure acquisition device arranged in the first flow path, which is the flow path between the inlet and the inlet of the condenser, and the first flow path are formed in an upward gradient from the expander toward the condenser. The calculation control device includes a plurality of temperature acquisition devices arranged at intervals in the section and a calculation control device that calculates and controls the parameters of the Rankin cycle system, and the calculation control device acquires the pressure acquisition device. Based on the value and the acquired values of the plurality of temperature acquisition devices, the degree of superheat of the working fluid at the installation position of each of the temperature acquisition devices is calculated, and based on the calculated degree of superheat of the working fluid. In addition to estimating the phase state of the working fluid at the installation position of each of the temperature acquisition devices, the installation position and gas state of the temperature acquisition device in which the estimated phase state of the working fluid is a liquid state It is configured to control to estimate that the liquid level of the working fluid in the liquid state stored in the first flow path is in a section at both ends of the installation position of the temperature acquisition device.
　また、上記の目的を達成するための本開示の態様のランキンサイクルシステムの制御方法は、作動流体を循環させる流路と、前記流路に配置されて前記作動流体を膨張させる膨張器と、前記膨張器より下流側の前記流路に配置されるとともにその入口が前記膨張器の出口より高い位置に配置されて前記作動流体を凝縮させる凝縮器と、前記膨張器の出口と前記凝縮器の入口の間の前記流路である第１流路に配置された圧力取得装置と、前記第１流路に関して、前記膨張器から前記凝縮器に向かって上り勾配に形成された区間に各々の間隔をあけて複数配置された温度取得装置と、を備えて構成されるランキンサイクルシステムの制御方法において、前記圧力取得装置により前記第１流路を通過する前記作動流体の圧力を取得するとともに、複数の前記温度取得装置によりその各々の設置位置での前記第１流路を通過する前記作動流体の温度を取得する第１ステップと、前記第１ステップで取得した前記作動流体の前記圧力と複数の前記温度取得装置の各々の設置位置での前記作動流体の前記温度とに基づいて、各々の前記温度取得装置の前記設置位置での前記作動流体の過熱度を算出する第２ステップと、前記第２ステップで算出した前記作動流体の前記過熱度に基づいて、各々の前記温度取得装置の前記設置位置での前記作動流体の相状態を推定する第３ステップと、前記第３ステップで前記作動流体の前記相状態が液体状態であると推定した前記温度取得装置の設置位置と気体状態であると推定した前記温度取得装置の設置位置とが両端となる区間に前記第１流路に貯留された前記液体状態の前記作動流体の液面があると推定する第４ステップと、を有することを特徴とする方法である。 Further, the control method of the Rankin cycle system according to the present disclosure aspect for achieving the above object includes a flow path for circulating a working fluid, an expander arranged in the flow path for expanding the working fluid, and the above. A condenser that is arranged in the flow path on the downstream side of the inflator and whose inlet is arranged at a position higher than the outlet of the inflator to condense the working fluid, and an outlet of the inflator and an inlet of the condenser. The distance between the pressure acquisition device arranged in the first flow path, which is the flow path between the two, and the section formed in an upward gradient from the inflator toward the condenser with respect to the first flow path. In a control method of a Rankin cycle system including a plurality of temperature acquisition devices arranged apart from each other, the pressure acquisition device acquires the pressure of the working fluid passing through the first flow path and a plurality of pressure acquisition devices. A first step of acquiring the temperature of the working fluid passing through the first flow path at each installation position by the temperature acquisition device, the pressure of the working fluid acquired in the first step, and a plurality of the above. The second step of calculating the degree of superheat of the working fluid at the installation position of each of the temperature acquisition devices based on the temperature of the working fluid at each installation position of the temperature acquisition device, and the second step. Based on the degree of superheat of the working fluid calculated in the step, the third step of estimating the phase state of the working fluid at the installation position of each of the temperature acquisition devices, and the third step of the working fluid The above-mentioned stored in the first flow path in a section where the installation position of the temperature acquisition device estimated to be in the liquid state and the installation position of the temperature acquisition device estimated to be in the gas state are both ends. It is a method characterized by having a fourth step of presuming that there is a liquid level of the working fluid in a liquid state.
　本開示によれば、膨張器の出口と凝縮器の入口の間の流路に貯留される凝縮液の量を高精度で推定することができる。 According to the present disclosure, the amount of condensate stored in the flow path between the outlet of the expander and the inlet of the condenser can be estimated with high accuracy.
図１は、本実施形態のランキンサイクルシステムを例示する図である。FIG. 1 is a diagram illustrating the Rankine cycle system of the present embodiment. 図２は、図１の膨張器と凝縮器の間の作動流体用の流路を拡大した図である。FIG. 2 is an enlarged view of the flow path for the working fluid between the expander and the condenser of FIG. 図３は、本実施形態のランキンサイクルシステムの制御方法を制御フローの形で例示する図である。FIG. 3 is a diagram illustrating a control method of the Rankine cycle system of the present embodiment in the form of a control flow.
　以下、本開示のランキンサイクルシステムについて、図面を参照しながら説明する。図１に例示するように、本実施形態のランキンサイクルシステム１は、作動流体用の流路（流路）２に、タンク３と、ポンプ（循環装置）４と、蒸発器５と、膨張器６と、凝縮器７と、を備えて構成されるシステムである。 Hereinafter, the Rankine cycle system of the present disclosure will be described with reference to the drawings. As illustrated in FIG. 1, the Rankine cycle system 1 of the present embodiment has a tank 3, a pump (circulator) 4, an evaporator 5, and an expander in a flow path (flow path) 2 for a working fluid. It is a system including 6 and a condenser 7.
　作動流体用の流路２は、作動流体Ｗを循環させる閉流路である。タンク３は、作動流体用の流路２に配置されて作動流体Ｗを貯留する。ポンプ４は、タンク３より下流側の作動流体用の流路２に配置されて、作動流体Ｗを圧送することで作動流体用の流路２に作動流体Ｗを循環させる。 The flow path 2 for the working fluid is a closed flow path for circulating the working fluid W. The tank 3 is arranged in the flow path 2 for the working fluid and stores the working fluid W. The pump 4 is arranged in the flow path 2 for the working fluid on the downstream side of the tank 3, and the working fluid W is circulated in the flow path 2 for the working fluid by pumping the working fluid W.
　蒸発器５は、ポンプ４より下流側の作動流体用の流路２に配置されて、エンジン（内燃機関）の排気Ｇと熱交換することで作動流体Ｗを加熱及び蒸発させる。膨張器６は、蒸発器５より下流側の作動流体用の流路２に配置されて作動流体Ｗを膨張させる。膨張器６の出力軸６ａには断接装置（クラッチ等）を介して駆動装置（エンジンやモータ等）が接続されており、断接装置の接続時に作動流体Ｗの膨張により出力軸６ａに発生した動力が駆動装置に伝達される。 The evaporator 5 is arranged in the flow path 2 for the working fluid on the downstream side of the pump 4, and heats and evaporates the working fluid W by exchanging heat with the exhaust G of the engine (internal combustion engine). The inflator 6 is arranged in the flow path 2 for the working fluid on the downstream side of the evaporator 5 to expand the working fluid W. A drive device (engine, motor, etc.) is connected to the output shaft 6a of the expander 6 via a disconnection device (clutch, etc.), and is generated in the output shaft 6a due to expansion of the working fluid W when the disconnection device is connected. The generated power is transmitted to the drive device.
　凝縮器７は、膨張器６より下流側の作動流体用の流路２に配置されて作動流体Ｗを凝縮させる。凝縮器７の入口７ａは膨張器６の出口６ｂより高い位置に配置されている。本実施形態では、膨張器６の出口６ｂと凝縮器７の入口７ａの間の流路を第１流路２ａと称す。凝縮器７の出口７ｂはタンク３の入口３ａより高い位置に配置されている。 The condenser 7 is arranged in the flow path 2 for the working fluid on the downstream side of the expander 6 to condense the working fluid W. The inlet 7a of the condenser 7 is located higher than the outlet 6b of the expander 6. In the present embodiment, the flow path between the outlet 6b of the expander 6 and the inlet 7a of the condenser 7 is referred to as a first flow path 2a. The outlet 7b of the condenser 7 is arranged higher than the inlet 3a of the tank 3.
　図１、図２に例示するように、第１流路２ａに関して、その少なくとも一部の流路は膨張器６から凝縮器７に向かって上り勾配に形成されている。本実施形態では、この上り勾配に形成されている流路を区間２ｂと称す。区間２ｂには、第１流路２ａで気体状態から液体状態に遷移した作動流体（凝縮液）ＷＬが貯留される。貯留される凝縮液ＷＬの量が多くなるにつれて、凝縮液ＷＬの液面ＬＳは高くなる。区間２ｂは、凝縮液ＷＬと気体状態の作動流体Ｗが熱交換可能な程度に接触可能なように構成される。区間２ｂは、凝縮液ＷＬが比較的発生しやすい箇所に設けることが好ましく、例えば、第１流路２ａに関してその中央位置から膨張器６側の流路に設けることが好ましい。凝縮液ＷＬは、第１流路２ａに関して膨張器６の出口６ｂに近くなるにつれて発生しやすい。 As illustrated in FIGS. 1 and 2, at least a part of the first flow path 2a is formed in an upward gradient from the expander 6 toward the condenser 7. In the present embodiment, the flow path formed on this uphill slope is referred to as a section 2b. In the section 2b, the working fluid (condensate) WL that has transitioned from the gas state to the liquid state in the first flow path 2a is stored. As the amount of the stored condensate WL increases, the liquid level LS of the condensate WL increases. The section 2b is configured so that the condensate WL and the working fluid W in the gaseous state can come into contact with each other to such an extent that heat exchange is possible. The section 2b is preferably provided at a position where the condensate WL is relatively likely to be generated, and for example, it is preferably provided in the flow path on the expander 6 side from the central position of the first flow path 2a. Condensate WL is more likely to occur as it approaches the outlet 6b of the expander 6 with respect to the first flow path 2a.
　本実施形態の区間２ｂは、膨張器６の出口６ｂより鉛直下方に延在する流路の最下部の位置（位置Ｂ１）から、この最下部の位置より凝縮器７の入口７ａ側に配置されるとともに膨張器６の出口６ｂより高く、かつ、凝縮器７の入口７ａより低い位置（位置Ｂ５）までの間に形成される上り勾配の流路である。凝縮液ＷＬは、膨張器６の出口６ｂから位置Ｂ１までの流路と区間２ｂに貯留されていく。貯留される凝縮液ＷＬの量が多くなるにつれて、区間２ｂにおける凝縮液ＷＬの液面ＬＳは位置Ｂ１を最下位置として上方に向かって高くなる。同様に、膨張器６の出口６ｂから位置Ｂ１までの流路における凝縮液ＷＬの液面も区間２ｂにおける凝縮液ＷＬの液面ＬＳと同じ高さ位置を維持しながら高くなる。 The section 2b of the present embodiment is arranged from the lowermost position (position B1) of the flow path extending vertically downward from the outlet 6b of the inflator 6 to the inlet 7a side of the condenser 7 from this lowermost position. It is an uphill flow path formed up to a position (position B5) higher than the outlet 6b of the expander 6 and lower than the inlet 7a of the condenser 7. The condensate WL is stored in the flow path and section 2b from the outlet 6b of the expander 6 to the position B1. As the amount of the stored condensate WL increases, the liquid level LS of the condensate WL in the section 2b increases upward with the position B1 as the lowest position. Similarly, the liquid level of the condensate WL in the flow path from the outlet 6b to the position B1 of the expander 6 also rises while maintaining the same height position as the liquid level LS of the condensate WL in the section 2b.
　図２に例示するように、第１流路２ａには、第１流路２ａを通過する作動流体Ｗの圧力を取得する圧力センサ（圧力取得装置）８が配置されている。圧力センサ８の配置位置は、第１流路２ａ内では作動流体Ｗの圧力は殆ど変化しないため、凝縮液ＷＬが発生する虞のない第１流路２ａ内の位置であればよい。本実施形態では、圧力センサ８は区間２ｂより凝縮器７の入口７ａ側の第１流路２ａにおける位置Ａ１に配置している。 As illustrated in FIG. 2, a pressure sensor (pressure acquisition device) 8 for acquiring the pressure of the working fluid W passing through the first flow path 2a is arranged in the first flow path 2a. Since the pressure of the working fluid W hardly changes in the first flow path 2a, the position of the pressure sensor 8 may be any position in the first flow path 2a where there is no possibility that the condensate WL is generated. In the present embodiment, the pressure sensor 8 is arranged at the position A1 in the first flow path 2a on the inlet 7a side of the condenser 7 from the section 2b.
　第１流路２ａの区間２ｂには複数（本実施形態では５個）の温度センサ（温度取得装置）９（９ａ～９ｅ）が各々の間隔をあけて配置されている。温度センサ９ａは位置Ｂ１に、温度センサ９ｂは位置Ｂ２に、温度センサ９ｃは位置Ｂ３に、温度センサ９ｄは位置Ｂ４に、温度センサ９ｅは位置Ｂ５に配置される。温度センサ９は、凝縮液ＷＬが貯留される虞のある位置に少なくとも１つ、凝縮液ＷＬが貯留される虞のない位置に少なくとも１つ配置されていればよく、その設置個数は特に限定されない。 A plurality of (five in this embodiment) temperature sensors (temperature acquisition devices) 9 (9a to 9e) are arranged in the section 2b of the first flow path 2a at intervals of each. The temperature sensor 9a is located at position B1, the temperature sensor 9b is located at position B2, the temperature sensor 9c is located at position B3, the temperature sensor 9d is located at position B4, and the temperature sensor 9e is located at position B5. At least one temperature sensor 9 may be arranged at a position where the condensate WL may be stored, and at least one may be arranged at a position where the condensate WL may not be stored, and the number of the temperature sensors 9 installed is not particularly limited. ..
　位置Ｂ１、Ｂ２、Ｂ３は、膨張器６の出口６ｂより低い位置に設定される。これらの位置Ｂ１～Ｂ３に凝縮液ＷＬの液面ＬＳがあっても凝縮液ＷＬは膨張器６に逆流して流入しない。位置Ｂ４、Ｂ５は、膨張器６の出口６ｂより高い位置に設定される。これらの位置Ｂ４、Ｂ５に凝縮液ＷＬの液面ＬＳがあると凝縮液ＷＬは膨張器６に逆流して流入する。位置Ｂ１、Ｂ２、Ｂ３、Ｂ４、Ｂ５の順に、膨張器６の出口６ｂに近い位置となり（凝縮器７の入口７ａから遠い位置となり）、かつ、低い位置となる。 Positions B1, B2, and B3 are set lower than the outlet 6b of the inflator 6. Even if there is a liquid level LS of the condensate WL at these positions B1 to B3, the condensate WL flows back into the expander 6 and does not flow in. The positions B4 and B5 are set higher than the outlet 6b of the inflator 6. If there is a liquid level LS of the condensate WL at these positions B4 and B5, the condensate WL flows back into the expander 6 and flows into the expander 6. Positions B1, B2, B3, B4, and B5 are located closer to the outlet 6b of the expander 6 (farther from the inlet 7a of the condenser 7) and lower.
　本実施形態のランキンサイクルシステム１には、このランキンサイクルシステム１のパラメータ（作動流体Ｗの過熱度や液面等）を演算し、制御する演算制御装置１０が備わる。演算制御装置１０は、各種情報処理を行うＣＰＵ（Central Processing Unit）、その各種情報処理を行うために用いられるプログラムや情報処理結果を読み書き可能な内部記憶装置、及び各種インターフェースなどから構成されるハードウエアである。演算制御装置１０には、圧力センサ８、温度センサ９、ポンプ４等の各種装置が電気的に接続される。 The Rankine cycle system 1 of the present embodiment is provided with a calculation control device 10 that calculates and controls the parameters of the Rankine cycle system 1 (such as the degree of superheat of the working fluid W and the liquid level). The arithmetic control device 10 is a 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 various information processing, and various interfaces. It is wear. Various devices such as a pressure sensor 8, a temperature sensor 9, and a pump 4 are electrically connected to the arithmetic control device 10.
　本実施形態のランキンサイクルシステム１では、演算制御装置１０が、圧力センサ８の取得値Ｐと複数の温度センサ９の取得値Ｔ（Ｔａ、Ｔｂ、Ｔｃ、Ｔｄ、Ｔｅ）とに基づいて、各々の温度センサ９の設置位置Ｂ１～Ｂ５での作動流体Ｗの過熱度を算出する。過熱度とは、作動流体Ｗの飽和温度よりも高温の過熱状態となった作動流体Ｗの温度と飽和温度との差である。 In the Rankine cycle system 1 of the present embodiment, the arithmetic control device 10 is based on the acquired value P of the pressure sensor 8 and the acquired value T (Ta, Tb, Tc, Td, Te) of the plurality of temperature sensors 9, respectively. The degree of superheat of the working fluid W at the installation positions B1 to B5 of the temperature sensor 9 is calculated. The degree of superheat is the difference between the temperature of the working fluid W and the saturation temperature, which are in a superheated state higher than the saturation temperature of the working fluid W.
　そして、演算制御装置１０が、この算出した作動流体Ｗの過熱度に基づいて各々の温度センサ９の設置位置Ｂ１～Ｂ５での作動流体Ｗの相状態（気体状態または液体状態）を推定する。言い換えれば、演算制御装置１０が、温度センサ９の取得値Ｔが予め設定された設定温度Ｔ１以上である場合には、その温度センサ９の設置位置での作動流体Ｗの相状態は気体状態であると判定し、設定温度Ｔ１未満である場合には液体状態であると推定する。設定温度Ｔ１は、作動流体Ｗの圧力Ｐに応じて変化する値で、作動流体Ｗの相状態が気体状態または液体状態のいずれかであることを推定可能な指標として実験等により予め設定される温度である。 Then, the arithmetic control device 10 estimates the phase state (gas state or liquid state) of the working fluid W at the installation positions B1 to B5 of each temperature sensor 9 based on the calculated superheat degree of the working fluid W. In other words, when the acquisition value T of the temperature sensor 9 is equal to or higher than the preset set temperature T1 of the arithmetic control device 10, the phase state of the working fluid W at the installation position of the temperature sensor 9 is in the gaseous state. If it is determined to be present and the temperature is lower than the set temperature T1, it is estimated to be in a liquid state. The set temperature T1 is a value that changes according to the pressure P of the working fluid W, and is preset by experiments or the like as an index that can estimate that the phase state of the working fluid W is either a gas state or a liquid state. The temperature.
　本実施形態では、演算制御装置１０は、位置Ｂ１の作動流体Ｗの温度Ｔａ、位置Ｂ２の作動流体Ｗの温度Ｔｂ、位置Ｂ３の作動流体Ｗの温度Ｔｃが設定温度Ｔ１未満であるため、位置Ｂ１～Ｂ３での作動流体Ｗは液体状態であると推定する。一方、演算制御装置１０は、位置Ｂ４の作動流体Ｗの温度Ｔｄ、位置Ｂ５の作動流体Ｗの温度Ｔｅが設定温度Ｔ１以上であるため、位置Ｂ４、Ｂ５での作動流体Ｗは気体状態であると推定する。 In the present embodiment, the arithmetic control device 10 has a position because the temperature Ta of the working fluid W at the position B1, the temperature Tb of the working fluid W at the position B2, and the temperature Tc of the working fluid W at the position B3 are less than the set temperature T1. It is estimated that the working fluid W in B1 to B3 is in a liquid state. On the other hand, in the arithmetic control device 10, since the temperature Td of the working fluid W at the position B4 and the temperature Te of the working fluid W at the position B5 are equal to or higher than the set temperature T1, the working fluid W at the positions B4 and B5 is in a gaseous state. Presumed to be.
　演算制御装置１０は、この推定した作動流体Ｗの相状態が液体状態である温度センサ９の設置位置と気体状態である温度センサ９の設置位置とが両端となる区間に第１流路２ａに貯留された凝縮液ＷＬの液面ＬＳがあると推定する制御を行うように構成される。本実施形態では、この両端となる区間は、作動流体Ｗの相状態が液体状態である温度センサ９ｃの設置位置Ｂ３と作動流体Ｗの相状態が気体状態である温度センサ９ｄの設置位置Ｂ４の間の区間である。 The arithmetic control device 10 is connected to the first flow path 2a in a section where the installation position of the temperature sensor 9 in which the estimated phase state of the working fluid W is in the liquid state and the installation position of the temperature sensor 9 in the gas state are both ends. It is configured to control the estimation that the liquid level LS of the stored condensate WL is present. In the present embodiment, the sections at both ends are the installation position B3 of the temperature sensor 9c in which the phase state of the working fluid W is in the liquid state and the installation position B4 of the temperature sensor 9d in which the phase state of the working fluid W is in the gas state. It is a section between.
　演算制御装置１０は、凝縮液ＷＬの液面ＬＳがある区間（位置Ｂ３と位置Ｂ４の間の区間）が区間２ｂの一部で実験等により予め設定された設定区間より上方の位置にある場合に、作動流体用の流路２を通過する作動流体Ｗの流量を通常の制御時の流量より低減されるようにポンプ４の出力を低下させる制御を行うように構成される。このポンプ４の出力を低下させる制御はエンジンの運転状態に依らずに行う。設定区間は、この区間に凝縮液ＷＬの液面ＬＳがある限りは凝縮液ＷＬが膨張器６に逆流して流入しないように設定される区間である。本実施形態では、設定区間は、位置Ｂ１～Ｂ３の区間である。ポンプ４の通常の制御時の作動流体Ｗの流量は、蒸発器５を通過する排気Ｇの温度及び流量に基づいて設定される。 In the arithmetic control device 10, when the section (the section between the position B3 and the position B4) where the liquid level LS of the condensate WL is located is a part of the section 2b and is located above the preset section set in advance by an experiment or the like. In addition, the output of the pump 4 is controlled to be reduced so that the flow rate of the working fluid W passing through the flow path 2 for the working fluid is reduced from the flow rate at the time of normal control. The control for reducing the output of the pump 4 is performed regardless of the operating state of the engine. The set section is a section set so that the condensate WL does not flow back into the expander 6 as long as there is a liquid level LS of the condensate WL in this section. In the present embodiment, the set section is a section between positions B1 to B3. The flow rate of the working fluid W during normal control of the pump 4 is set based on the temperature and flow rate of the exhaust gas G passing through the evaporator 5.
　このようにポンプ４の出力を低下させて作動流体Ｗの流量を低減させることで、蒸発器５で作動流体Ｗと排気Ｇとが熱交換する時間を長くして、作動流体用の流路２ａを通過する作動流体Ｗの温度Ｔを設定温度Ｔ１以上に昇温させる。設定温度Ｔ１は、第１流路２ａに貯留された凝縮液ＷＬを蒸発可能な温度として実験等により予め設定される温度である。第１流路２ａは凝縮液ＷＬと気体状態の作動流体Ｗが熱交換可能な程度に接触可能なように構成されているため、設定温度Ｔ１以上の温度Ｔである作動流体Ｗが第１流路２ａを通過することで、第１流路２ａに貯留された凝縮液ＷＬは気体状態の作動流体Ｗと熱交換して蒸発する。 By reducing the output of the pump 4 and reducing the flow rate of the working fluid W in this way, the time for heat exchange between the working fluid W and the exhaust G in the evaporator 5 is lengthened, and the flow path 2a for the working fluid is extended. The temperature T of the working fluid W passing through the above is raised to the set temperature T1 or higher. The set temperature T1 is a temperature preset by an experiment or the like as a temperature at which the condensate WL stored in the first flow path 2a can be evaporated. Since the first flow path 2a is configured so that the condensate WL and the working fluid W in the gaseous state can come into contact with each other to such an extent that heat exchange is possible, the working fluid W having a temperature T equal to or higher than the set temperature T1 is the first flow. By passing through the path 2a, the condensate WL stored in the first flow path 2a exchanges heat with the working fluid W in a gaseous state and evaporates.
　このポンプ４の出力を低下させる制御は、少なくとも凝縮液ＷＬの液面ＬＳが設定区間に収まるまで行う。本実施形態では、このポンプ４の出力を低下させる制御を凝縮液ＷＬの液面ＬＳが位置Ｂ１～Ｂ３の区間に収まるまで行う。なお、演算制御装置１０が、このポンプ４の出力を低下させる制御を、全ての作動流体Ｗの温度の計測位置（本実施形態ではＢ１～Ｂ５）における作動流体Ｗの相状態が気体状態であると判定するまで行うように構成してもよい。この場合は、第１流路２ａに貯留された凝縮液ＷＬがほとんど存在しない状態となるので、凝縮液ＷＬの逆流による膨張器６の出力低下を大幅に抑制することができる。 Control to reduce the output of the pump 4 is performed at least until the liquid level LS of the condensate WL falls within the set section. In the present embodiment, the control for reducing the output of the pump 4 is performed until the liquid level LS of the condensate WL falls within the section of positions B1 to B3. It should be noted that the arithmetic control device 10 controls the reduction of the output of the pump 4, and the phase state of the working fluid W at the measurement positions of the temperatures of all the working fluids W (B1 to B5 in this embodiment) is the gas state. It may be configured to carry out until it is determined. In this case, since the condensed liquid WL stored in the first flow path 2a is almost absent, it is possible to significantly suppress a decrease in the output of the expander 6 due to the backflow of the condensed liquid WL.
　演算制御装置１０が、凝縮液ＷＬの液面ＬＳが位置Ｂ４～Ｂ５の区間にあると推定する場合には、凝縮液ＷＬが膨張器６に逆流して流入しており、膨張器６の出力を低下させている。この場合には、演算制御装置１０が、凝縮液ＷＬの液面ＬＳが位置Ｂ３～Ｂ４の区間にある場合よりもポンプ４の出力をより一層低下させる制御を行って作動流体Ｗの温度をさらに昇温させることが好ましい。このようにすることで、凝縮液ＷＬの蒸発がさらに促進されるので、膨張器６の出力低下を抑制することができる。 When the arithmetic control device 10 estimates that the liquid level LS of the condensate WL is in the section between positions B4 to B5, the condensate WL flows back into the expander 6 and flows into the expander 6, and the output of the expander 6 is output. Is decreasing. In this case, the arithmetic control device 10 further controls the temperature of the working fluid W by controlling the output of the pump 4 to be further lowered as compared with the case where the liquid level LS of the condensate WL is in the section of positions B3 to B4. It is preferable to raise the temperature. By doing so, the evaporation of the condensate WL is further promoted, so that the output decrease of the expander 6 can be suppressed.
　本実施形態のランキンサイクルシステム１を基にした制御フローについて、言い換えれば、ランキンサイクルシステムの制御方法について、その一例を制御フローの形で図３を参照しながら説明する。図３に示す制御フローは、エンジンが運転状態であるときに周期的に行われる制御フローである。 The control flow based on the Rankine cycle system 1 of the present embodiment, in other words, the control method of the Rankine cycle system will be described with reference to FIG. 3 in the form of an example of the control flow. The control flow shown in FIG. 3 is a control flow that is periodically performed when the engine is in an operating state.
　図３に示す制御フローがスタートすると、ステップＳ１０（第１ステップ）にて、圧力センサ８により第１流路２ａを通過する作動流体Ｗの圧力Ｐを取得するとともに、複数の温度センサ９によりその各々の設置位置Ｂ１～Ｂ５での第１流路２ａを通過する作動流体Ｗの温度Ｔを取得する。ステップＳ１０を実施後、ステップＳ２０に進む。 When the control flow shown in FIG. 3 starts, in step S10 (first step), the pressure sensor 8 acquires the pressure P of the working fluid W passing through the first flow path 2a, and the plurality of temperature sensors 9 obtain the pressure P. The temperature T of the working fluid W passing through the first flow path 2a at each of the installation positions B1 to B5 is acquired. After performing step S10, the process proceeds to step S20.
　ステップＳ２０（第２ステップ）にて、演算制御装置１０は、ステップＳ１０で取得した作動流体Ｗの圧力Ｐと複数の温度センサ９の各々の設置位置Ｂ１～Ｂ５での作動流体Ｗの温度Ｔとに基づいて、各々の温度センサ９の設置位置Ｂ１～Ｂ５での作動流体Ｗの過熱度を算出する。ステップＳ２０を実施後、ステップＳ３０を実施する。 In step S20 (second step), the arithmetic control device 10 determines the pressure P of the working fluid W acquired in step S10 and the temperature T of the working fluid W at the respective installation positions B1 to B5 of the plurality of temperature sensors 9. Based on the above, the degree of superheat of the working fluid W at the installation positions B1 to B5 of each temperature sensor 9 is calculated. After performing step S20, step S30 is carried out.
　ステップＳ３０（第３ステップ）にて、演算制御装置１０は、ステップＳ２０で算出した過熱度に基づいて、各々の温度センサ９の設置位置Ｂ１～Ｂ５での作動流体Ｗの相状態を推定する。ステップＳ３０を実施後、ステップＳ４０に進む。 In step S30 (third step), the arithmetic control device 10 estimates the phase state of the working fluid W at the installation positions B1 to B5 of each temperature sensor 9 based on the degree of superheat calculated in step S20. After performing step S30, the process proceeds to step S40.
　ステップＳ４０（第４ステップ）にて、演算制御装置１０は、ステップＳ３０で作動流体Ｗの相状態が液体状態であると推定した温度センサ９の設置位置Ｂ３と気体状態であると推定した温度センサ９の設置位置Ｂ４とが両端となる区間に第１流路２ａに貯留された凝縮液ＷＬの液面ＬＳがあると推定する。ステップＳ４０を実施後、ステップＳ５０に進む。 In step S40 (fourth step), the arithmetic control device 10 estimates that the phase state of the working fluid W is the installation position B3 of the temperature sensor 9 estimated to be in the liquid state and the temperature sensor estimated to be in the gas state in step S30. It is presumed that the liquid level LS of the condensate WL stored in the first flow path 2a is in the section where the installation position B4 of 9 is at both ends. After performing step S40, the process proceeds to step S50.
　ステップＳ５０にて、演算制御装置１０は、ステップＳ４０で推定した凝縮液ＷＬの液面ＬＳがある区間が設定区間より上方の位置にあるか否かを判定する（第１区間判定）。凝縮液ＷＬの液面ＬＳがある区間が設定区間より上方の位置にある場合（Ｓ５０：ＹＥＳ）には、ステップＳ６０に進む。凝縮液ＷＬの液面ＬＳがある区間が設定区間より上方の位置にない場合（Ｓ５０：ＮＯ）には、ステップＳ７０に進む。 In step S50, the arithmetic control device 10 determines whether or not the section with the liquid level LS of the condensate WL estimated in step S40 is located above the set section (first section determination). When the section where the liquid level LS of the condensate WL is located is located above the set section (S50: YES), the process proceeds to step S60. If the section where the liquid level LS of the condensate WL is located is not located above the set section (S50: NO), the process proceeds to step S70.
　ステップＳ６０にて、演算制御装置１０は、第１流路２ａを通過する作動流体Ｗの流量が通常の制御時の流量より低減されるようにポンプ４の出力を低下させる制御を行う。このように制御することで、第１流路２ａを通過する作動流体Ｗの温度Ｔを設定温度Ｔ１以上に昇温させて、第１流路２ａに貯留した凝縮液ＷＬを蒸発させる。ステップＳ６０を実施後、ステップＳ１０に戻る。 In step S60, the arithmetic control device 10 controls to reduce the output of the pump 4 so that the flow rate of the working fluid W passing through the first flow path 2a is reduced from the flow rate at the time of normal control. By controlling in this way, the temperature T of the working fluid W passing through the first flow path 2a is raised to a set temperature T1 or higher, and the condensate WL stored in the first flow path 2a is evaporated. After performing step S60, the process returns to step S10.
　ステップＳ７０にて、演算制御装置１０は、ポンプ４の出力が通常の制御時の出力より低下しているか否かを判定する。言い換えれば、ステップＳ６０を通過しているか否かを判定する。ポンプ４の出力が通常の制御時の出力より低下している場合（Ｓ７０：ＹＥＳ）には、ステップＳ８０に進む。ポンプ４の出力が通常の制御時の出力より低下していない場合（Ｓ７０：ＮＯ）には、リターンに進んで、本制御フローを終了する。 In step S70, the arithmetic control device 10 determines whether or not the output of the pump 4 is lower than the output during normal control. In other words, it is determined whether or not the step S60 has been passed. If the output of the pump 4 is lower than the output during normal control (S70: YES), the process proceeds to step S80. If the output of the pump 4 is not lower than the output during normal control (S70: NO), the process proceeds to return and the present control flow is terminated.
　ステップＳ８０にて、演算制御装置１０は、ステップＳ４０で推定した凝縮液ＷＬの液面ＬＳがある区間が設定区間の一部で比較的下方の区間として予め設定された第２設定区間にあるか否かを判定する（第２区間判定）。第２設定区間は、ポンプ４の出力を低下させる制御の終了時点から次回のポンプ４の出力を低下させる制御の開始時点までの時間をポンプ４の耐久性に影響を与えない程度の時間とすることが可能な区間である。本実施形態では、第２設定区間は位置Ｂ１と位置Ｂ２の間の区間である。凝縮液ＷＬの液面ＬＳがある区間が第２設定区間にある場合（Ｓ８０：ＹＥＳ）には、ステップＳ９０に進む。凝縮液ＷＬの液面ＬＳがある区間が第２設定区間にない場合（Ｓ８０：ＮＯ）には、ステップＳ１０に戻る。 In step S80, in the arithmetic control device 10, is the section in which the liquid level LS of the condensate WL estimated in step S40 is located in the second set section preset as a part of the set section and relatively lower section? Judgment whether or not (second section judgment). In the second set section, the time from the end of the control for reducing the output of the pump 4 to the start of the control for reducing the output of the next pump 4 is set to a time that does not affect the durability of the pump 4. It is a possible section. In the present embodiment, the second set section is a section between the position B1 and the position B2. If the section where the liquid level LS of the condensate WL is located is in the second set section (S80: YES), the process proceeds to step S90. If the section where the liquid level LS of the condensate WL is present is not in the second set section (S80: NO), the process returns to step S10.
　なお、ステップＳ８０の判定は、全ての作動流体Ｗの温度の計測位置（本実施形態ではＢ１～Ｂ５）における作動流体Ｗの相状態が気体状態となったか否かの判定で代用してもよい。全ての作動流体Ｗの温度の計測位置における作動流体Ｗの相状態が気体状態である場合（Ｓ８０：ＹＥＳ）には、ステップＳ９０に進む。作動流体Ｗの相状態が気体状態でない温度の計測位置がある場合（Ｓ８０：ＮＯ）には、ステップＳ１０に戻る。 The determination in step S80 may be substituted by determining whether or not the phase state of the working fluid W at the measurement positions of the temperatures of all the working fluids W (B1 to B5 in this embodiment) has become a gas state. .. If the phase state of the working fluid W at the measurement position of the temperature of all the working fluid W is a gas state (S80: YES), the process proceeds to step S90. If there is a temperature measurement position where the phase state of the working fluid W is not the gaseous state (S80: NO), the process returns to step S10.
　ステップＳ９０にて、演算制御装置１０は、ポンプ４の出力を通常の制御時の出力に戻す。ステップＳ９０を実施後、リターンに進んで、本制御フローを終了する。 In step S90, the arithmetic control device 10 returns the output of the pump 4 to the output during normal control. After executing step S90, the process proceeds to return and the present control flow is terminated.
　以上により、本実施形態のランキンサイクルシステム１及びその制御方法によれば、膨張器６の出口６ｂと凝縮器７の入口７ａの間の第１流路２ａに貯留される凝縮液ＷＬの量を高精度で推定することができる。 Based on the above, according to the Rankine cycle system 1 of the present embodiment and its control method, the amount of condensate WL stored in the first flow path 2a between the outlet 6b of the expander 6 and the inlet 7a of the condenser 7 is determined. It can be estimated with high accuracy.
　本出願は、2019年3月18日付で出願された日本国特許出願（特願2019-049438）に基づくものであり、その内容はここに参照として取り込まれる。 This application is based on a Japanese patent application (Japanese Patent Application No. 2019-049438) filed on March 18, 2019, the contents of which are incorporated herein by reference.
　本発明は、膨張器の出口と凝縮器の入口の間の流路に貯留される凝縮液の量を高精度で推定することができるという効果を有し、ランキンサイクルシステム及びその制御方法等に有用である。 The present invention has the effect of being able to estimate the amount of condensate stored in the flow path between the outlet of the expander and the inlet of the condenser with high accuracy, and is used in the Rankine cycle system and its control method. It is useful.
　１　ランキンサイクルシステム
　２　作動流体用の流路
　２ａ　第１流路
　２ｂ　第１流路の上り勾配の区間
　３　タンク
　３ａ　タンクの入口
　４　ポンプ
　５　蒸発器
　６　膨張器
　６ａ　出力軸
　６ｂ　膨張器の出口
　７　凝縮器
　７ａ　凝縮器の入口
　７ｂ　凝縮器の出口
　８　圧力センサ（圧力取得装置）
　９、９ａ、９ｂ、９ｃ、９ｄ、９ｅ　温度センサ（温度取得装置）
　１０　演算制御装置
　ＷＬ　凝縮液
　ＬＳ　凝縮液の液面 1 Rankine cycle system 2 Flow path for working fluid 2a 1st flow path 2b Uphill section of 1st flow path 3 Tank 3a Tank inlet 4 Pump 5 Evaporator 6 Inflator 6a Output shaft 6b Inflator outlet 7 Condensation Instrument 7a Condenser inlet 7b Condenser outlet 8 Pressure sensor (pressure acquisition device)
9, 9a, 9b, 9c, 9d, 9e Temperature sensor (temperature acquisition device)
10 Arithmetic control device WL Condensate LS Condensate level

Claims (3)

  1. 　作動流体を循環させる流路と、前記流路に配置されて前記作動流体を膨張させる膨張器と、前記膨張器より下流側の前記流路に配置されるとともにその入口が前記膨張器の出口より高い位置に配置されて前記作動流体を凝縮させる凝縮器と、を備えて構成されるランキンサイクルシステムにおいて、
    　前記膨張器の出口と前記凝縮器の入口の間の前記流路である第１流路に配置された圧力取得装置と、
    　前記第１流路に関して、前記膨張器から前記凝縮器に向かって上り勾配に形成された区間に各々の間隔をあけて複数配置された温度取得装置と、
    　前記ランキンサイクルシステムのパラメータを演算し、制御する演算制御装置と、を備えて、
    　前記演算制御装置が、
    　前記圧力取得装置の取得値と複数の前記温度取得装置の取得値とに基づいて、各々の前記温度取得装置の設置位置での前記作動流体の過熱度を算出して、この算出した前記作動流体の前記過熱度に基づいて各々の前記温度取得装置の前記設置位置での前記作動流体の相状態を推定するとともに、この推定した前記作動流体の前記相状態が液体状態である前記温度取得装置の設置位置と気体状態である前記温度取得装置の設置位置とが両端となる区間に前記第１流路に貯留された前記液体状態の前記作動流体の液面があると推定する制御を行うように構成されるランキンサイクルシステム。     A flow path that circulates the working fluid, an expander that is arranged in the flow path to expand the working fluid, and an inflator that is arranged in the flow path on the downstream side of the inflator and whose inlet is from the outlet of the inflator. In a Rankine cycle system configured with a condenser that is located high and condenses the working fluid.
    A pressure acquisition device arranged in a first flow path, which is the flow path between the outlet of the expander and the inlet of the condenser,
    With respect to the first flow path, a plurality of temperature acquisition devices arranged at intervals in a section formed in an upward gradient from the expander to the condenser, and
    A calculation control device that calculates and controls the parameters of the Rankine cycle system is provided.
    The arithmetic control device
    Based on the acquired values of the pressure acquisition device and the acquired values of the plurality of temperature acquisition devices, the degree of superheat of the working fluid at the installation position of each of the temperature acquisition devices is calculated, and the calculated working fluid is calculated. Based on the degree of superheat, the phase state of the working fluid at the installation position of each of the temperature acquisition devices is estimated, and the estimated phase state of the working fluid is the liquid state of the temperature acquisition device. Control is performed to estimate that the liquid level of the working fluid in the liquid state stored in the first flow path is in the section where the installation position and the installation position of the temperature acquisition device in the gaseous state are both ends. Rankin cycle system composed.
  2. 　作動流体を循環させる循環装置を前記流路に備えて、
    　前記演算制御装置が、
    　前記液体状態の前記作動流体の前記液面がある区間が、前記上り勾配に形成された区間の一部で予め設定された設定区間より上方の位置にある場合に、前記流路を通過する前記作動流体の流量が通常の制御時の流量より低減されるように前記循環装置の出力を低下させることで、前記流路を通過する前記作動流体の温度を前記第１流路に貯留された前記液体状態の前記作動流体を蒸発可能な温度として予め設定された設定温度以上に昇温させる制御を行うように構成される請求項１に記載のランキンサイクルシステム。     The flow path is provided with a circulation device for circulating the working fluid.
    The arithmetic control device
    When the section of the working fluid in the liquid state where the liquid level is located is located above a preset section set in a part of the section formed on the upslope, the section passing through the flow path. By reducing the output of the circulation device so that the flow rate of the working fluid is reduced from the flow rate during normal control, the temperature of the working fluid passing through the flow path is stored in the first flow path. The Rankin cycle system according to claim 1, wherein the working fluid in a liquid state is controlled to be raised to a temperature higher than a preset set temperature as an evaporable temperature.
  3. 　作動流体を循環させる流路と、前記流路に配置されて前記作動流体を膨張させる膨張器と、前記膨張器より下流側の前記流路に配置されるとともにその入口が前記膨張器の出口より高い位置に配置されて前記作動流体を凝縮させる凝縮器と、前記膨張器の出口と前記凝縮器の入口の間の前記流路である第１流路に配置された圧力取得装置と、前記第１流路に関して、前記膨張器から前記凝縮器に向かって上り勾配に形成された区間に各々の間隔をあけて複数配置された温度取得装置と、を備えて構成されるランキンサイクルシステムの制御方法において、
    　前記圧力取得装置により前記第１流路を通過する前記作動流体の圧力を取得するとともに、複数の前記温度取得装置によりその各々の設置位置での前記第１流路を通過する前記作動流体の温度を取得する第１ステップと、
    　前記第１ステップで取得した前記作動流体の前記圧力と複数の前記温度取得装置の各々の設置位置での前記作動流体の前記温度とに基づいて、各々の前記温度取得装置の設置位置での前記作動流体の過熱度を算出する第２ステップと、
    　前記第２ステップで算出した前記作動流体の前記過熱度に基づいて、各々の前記温度取得装置の前記設置位置での前記作動流体の相状態を推定する第３ステップと、
    　前記第３ステップで前記作動流体の前記相状態が液体状態であると推定した前記温度取得装置の設置位置と気体状態であると推定した前記温度取得装置の設置位置とが両端となる区間に前記第１流路に貯留された前記液体状態の前記作動流体の液面があると推定する第４ステップと、
    　を有することを特徴とするランキンサイクルシステムの制御方法。     A flow path that circulates the working fluid, an expander that is arranged in the flow path to expand the working fluid, and an inflator that is arranged in the flow path on the downstream side of the inflator and whose inlet is from the outlet of the inflator. A condenser arranged at a high position to condense the working fluid, a pressure acquisition device arranged in the first flow path which is the flow path between the outlet of the expander and the inlet of the condenser, and the first. A control method of a Rankine cycle system including a plurality of temperature acquisition devices arranged at intervals in a section formed in an upward gradient from the inflator to the condenser with respect to one flow path. In
    The pressure acquisition device acquires the pressure of the working fluid passing through the first flow path, and the plurality of temperature acquisition devices acquire the temperature of the working fluid passing through the first flow path at each installation position. The first step to get
    Based on the pressure of the working fluid acquired in the first step and the temperature of the working fluid at each installation position of the plurality of temperature acquisition devices, the said at the installation position of each of the temperature acquisition devices. The second step of calculating the degree of overheating of the working fluid and
    A third step of estimating the phase state of the working fluid at the installation position of each of the temperature acquisition devices based on the degree of superheat of the working fluid calculated in the second step.
    In the section where the installation position of the temperature acquisition device estimated to be in the liquid state and the installation position of the temperature acquisition device estimated to be in the gas state of the working fluid in the third step are both ends. The fourth step of presuming that there is a liquid level of the working fluid in the liquid state stored in the first flow path, and
    A method of controlling a Rankine cycle system, characterized in that it has.
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Citations (4)

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JP2005146990A (en) * 2003-11-14 2005-06-09 Honda Motor Co Ltd Rankine cycle device
JP2006037849A (en) * 2004-07-27 2006-02-09 Ebara Corp Power recovery device and operation method thereof
JP2012202269A (en) * 2011-03-24 2012-10-22 Kobe Steel Ltd Binary generator and control method for the same
JP2015108339A (en) * 2013-12-05 2015-06-11 トヨタ自動車株式会社 Waste heat recovery device

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JP5494426B2 (en) 2010-11-09 2014-05-14 トヨタ自動車株式会社 Rankine cycle system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005146990A (en) * 2003-11-14 2005-06-09 Honda Motor Co Ltd Rankine cycle device
JP2006037849A (en) * 2004-07-27 2006-02-09 Ebara Corp Power recovery device and operation method thereof
JP2012202269A (en) * 2011-03-24 2012-10-22 Kobe Steel Ltd Binary generator and control method for the same
JP2015108339A (en) * 2013-12-05 2015-06-11 トヨタ自動車株式会社 Waste heat recovery device

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