JP4241127B2 - Transcritical refrigerant cycle equipment - Google Patents

Transcritical refrigerant cycle equipment Download PDF

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Publication number
JP4241127B2
JP4241127B2 JP2003083061A JP2003083061A JP4241127B2 JP 4241127 B2 JP4241127 B2 JP 4241127B2 JP 2003083061 A JP2003083061 A JP 2003083061A JP 2003083061 A JP2003083061 A JP 2003083061A JP 4241127 B2 JP4241127 B2 JP 4241127B2
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Prior art keywords
compressor
pressure side
refrigerant
temperature
rotational speed
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JP2003083061A
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JP2004293815A (en
Inventor
茂弥 石垣
兼三 松本
晴久 山崎
正司 山中
一昭 藤原
恒久 湯本
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Sanyo Electric Co Ltd
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Sanyo Electric Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
    • F04C18/30—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
    • F04C18/34—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members
    • F04C18/356—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the outer member
    • F04C18/3562—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the outer member the inner and outer member being in contact along one line or continuous surfaces substantially parallel to the axis of rotation
    • F04C18/3564—Rotary-piston pumps specially adapted for elastic fluids having the characteristics covered by two or more of groups F04C18/02, F04C18/08, F04C18/22, F04C18/24, F04C18/48, or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F04C18/08 or F04C18/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the outer member the inner and outer member being in contact along one line or continuous surfaces substantially parallel to the axis of rotation the surfaces of the inner and outer member, forming the working space, being surfaces of revolution
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/001—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids of similar working principle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C23/00—Combinations of two or more pumps, each being of rotary-piston or oscillating-piston type, specially adapted for elastic fluids; Pumping installations specially adapted for elastic fluids; Multi-stage pumps specially adapted for elastic fluids
    • F04C23/008—Hermetic pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B1/00—Compression machines, plants or systems with non-reversible cycle
    • F25B1/10—Compression machines, plants or systems with non-reversible cycle with multi-stage compression
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/06—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide
    • F25B2309/061—Compression machines, plants or systems characterised by the refrigerant being carbon dioxide with cycle highest pressure above the supercritical pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/02—Compressor control
    • F25B2600/021—Inverters therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/19—Pressures
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2115—Temperatures of a compressor or the drive means therefor
    • F25B2700/21151—Temperatures of a compressor or the drive means therefor at the suction side of the compressor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2115—Temperatures of a compressor or the drive means therefor
    • F25B2700/21152—Temperatures of a compressor or the drive means therefor at the discharge side of the compressor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
    • F25B2700/21—Temperatures
    • F25B2700/2117—Temperatures of an evaporator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B40/00—Subcoolers, desuperheaters or superheaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/002—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant
    • F25B9/008—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the refrigerant the refrigerant being carbon dioxide
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、圧縮機、ガスクーラ、減圧装置及び蒸発器を順次環状に配管接続して成り、高圧側が超臨界圧力となる遷臨界冷媒サイクル装置に関するものである。
【０００２】
【従来の技術】
近年の地球環境破壊問題を解決するため、この種冷凍・空調用の冷媒サイクル装置においてもオゾン層破壊の危険性の高いフロン系冷媒を用いることが禁止若しくは規制されるように成ってきている。そこで、自然冷媒の一つである二酸化炭素を用いた冷媒サイクル装置が開発されてきている（例えば、特許文献１参照）。係る二酸化炭素のような自然物質を冷媒として使用した場合、その臨界温度が極めて低いために高圧側は臨界圧力未満とはならず、専ら超臨界圧力にて運転されることになる。
【０００３】
【特許文献１】
特公平７−１８６０２号公報
【０００４】
ところで、係る冷媒サイクル装置では高圧側における冷媒の放熱を促進し、また、低圧側における冷媒の過熱を行うために、内部熱交換器が使用される。この内熱交換器は、冷媒サイクル装置のガスクーラを出た高圧側冷媒と、蒸発器を出た低圧側冷媒とを熱交換させ、減圧装置に入る高圧側冷媒温度を低下させると共に、圧縮機に吸い込まれる低圧側冷媒の過熱度をとる。これにより、アキュムレータを設けること無く圧縮機に液冷媒が吸い込まれる不都合を回避できるものであった。
【０００５】
【発明が解決しようとする課題】
しかしながら、例えば圧縮機の起動後、その回転数を上昇させていく過程において高圧側冷媒の温度が依然高くなっていない段階では、ある回転数域において、内部熱交換器を経て圧縮機に吸い込まれる低圧側冷媒に対する内部熱交換器における高圧側冷媒の加熱能力が不足する状況が生じる。
【０００６】
同じことは定常運転中に圧縮機の回転数を上昇させていく過程や圧縮機の回転数を低下させていく過程においても生じる。即ち、圧縮機の回転数を低下させると内部熱交換器における高圧側冷媒の低圧側冷媒に対する加熱能力も低下するからである。このような状況となると、低圧側冷媒の十分な過熱度をとることができなくなり、圧縮機に液冷媒が吸い込まれて所謂液圧縮が発生する問題が生じる。
【０００７】
本発明は、係る従来の技術的課題を解決するために成されたものであり、内部熱交換器を備えた遷臨界冷媒サイクル装置において、圧縮機の回転数を上昇させ、或いは、低下させる際に生じる圧縮機の液圧縮を効果的に防止することを目的とする。
【０００８】
【課題を解決するための手段】
即ち、請求項１の発明では、圧縮機、ガスクーラ、減圧装置及び蒸発器を順次環状に配管接続して成り、ガスクーラから出た高圧側冷媒と蒸発器から出た低圧側冷媒とを熱交換させるための内部熱交換器を備え、高圧側が超臨界圧力となる遷臨界冷媒サイクル装置において、圧縮機の回転数を制御する制御装置を備え、該制御装置は、内部熱交換器の高圧側冷媒温度、若しくは、当該内部熱交換器の低圧側冷媒温度を示す指標に基づき、圧縮機の回転数を制御すると共に、前記圧縮機の回転数を上昇させる過程において、指標の所定範囲内で当該圧縮機の回転数上昇を禁止し、若しくは、回転数を低下させるので、圧縮機の回転数を上昇させていく過程で内部熱交換器における高圧側冷媒による低圧側冷媒の加熱能力が不足することによる圧縮機の液圧縮の発生を未然に回避することが可能となる。また、高圧側の圧力が異常に上昇する不都合も回避できるので、信頼性も向上する。
【０００９】
特に、請求項２の如く高圧側冷媒の圧力が上昇した場合、圧縮機の回転数上昇を禁止し、若しくは、回転数を低下させ、或いは、当該圧縮機を停止させれば、起動時における高圧側圧力の異常上昇を確実に防止できるようになる。これは特に請求項５の如く圧力が高くなる二酸化炭素を冷媒として使用する場合には極めて有効となる。
【００１０】
請求項３の発明では、圧縮機、ガスクーラ、減圧装置及び蒸発器を順次環状に配管接続して成り、ガスクーラから出た高圧側冷媒と蒸発器から出た低圧側冷媒とを熱交換させるための内部熱交換器を備え、高圧側が超臨界圧力となる遷臨界冷媒サイクル装置において、圧縮機の回転数を制御する制御装置を備え、該制御装置は、内部熱交換器の高圧側冷媒温度、若しくは、当該内部熱交換器の低圧側冷媒温度を示す指標に基づき、圧縮機の回転数を制御すると共に、圧縮機の回転数を低下させる過程において、指標の所定範囲内で当 該圧縮機の回転数低下を禁止し、若しくは、回転数を上昇させるので、圧縮機の回転数を低下させていく過程で内部熱交換器における高圧側冷媒による低圧側冷媒の加熱能力が不足することによる圧縮機の液圧縮を回避することができるようになる。
【００１１】
請求項４の発明では、圧縮機、ガスクーラ、減圧装置及び蒸発器を順次環状に配管接続して成り、ガスクーラから出た高圧側冷媒と蒸発器から出た低圧側冷媒とを熱交換させるための内部熱交換器を備え、高圧側が超臨界圧力となる遷臨界冷媒サイクル装置において、圧縮機の回転数を制御する制御装置を備え、該制御装置は、内部熱交換器の高圧側冷媒温度、若しくは、当該内部熱交換器の低圧側冷媒温度を示す指標に基づき、圧縮機の回転数を制御すると共に、圧縮機の回転数を上昇させる過程において、指標の所定範囲内で当該圧縮機の回転数上昇を禁止し、若しくは、回転数を低下させ、圧縮機の回転数を低下させる過程においては、指標の所定範囲内で当該圧縮機の回転数低下を禁止し、若しくは、回転数を上昇させるので、圧縮機の回転数を上昇させていく過程で内部熱交換器における高圧側冷媒による低圧側冷媒の加熱能力が不足することによる圧縮機の液圧縮の発生を未然に回避することが可能となる。また、高圧側の圧力が異常に上昇する不都合も回避できるので、信頼性も向上する。
【００１２】
更に、圧縮機の回転数を低下させていく過程で内部熱交換器における高圧側冷媒による低圧側冷媒の加熱能力が不足することによる圧縮機の液圧縮を回避することができるようになる。
【００１３】
また、上記各発明において、圧縮機の吐出側冷媒温度や吸込側冷媒温度を前記指標とすれば、内部熱交換器に入る高圧側冷媒の温度、若しくは、当該内部熱交換器を出た低圧側冷媒の温度を的確に判断できる。
【００１４】
特に、蒸発器における冷媒の蒸発温度に基づいて圧縮機の吐出側冷媒温度から得られた前記指標の所定範囲を補正すれば、より的確な圧縮機の回転数制御による液圧縮の防止を行うことができるようになる。
【００１５】
また、圧縮機の吸込側冷媒温度から前記指標を得る場合にはガスクーラ出口における冷媒の温度に基づいて前記指標の所定範囲を補正することでも圧縮機の回転数上昇を迅速に行いながら圧縮機の液圧縮を防止できるようになる。
【００１６】
上記各発明は、特に請求項５の如く圧力が高くなる二酸化炭素を冷媒として使用する場合には極めて有効となる。
【００１７】
【発明の実施の形態】
以下、図面に基づき本発明の実施形態を詳述する。図１は本発明の遷臨界冷媒サイクル装置に使用するコンプレッサの実施例として、第１及び第２の回転圧縮要素３２、３４（何れも圧縮要素の一例である）を備えた内部中間圧型多段（２段）圧縮式ロータリコンプレッサ１０の縦断側面図である。尚、実施例の遷臨界冷媒サイクル装置は高圧側が超臨界圧力となる。
【００１８】
この図において、１０は二酸化炭素（ＣＯ2）を冷媒として使用する内部中間圧型多段圧縮式ロータリコンプレッサ（本発明のコンプレッサに相当）で、このロータリコンプレッサ１０は、鋼板からなる円筒状の密閉容器１２と、この密閉容器１２の内部空間の上側に配置収納された電動要素１４及びこの電動要素１４の下側に配置され、電動要素１４の回転軸１６により駆動される第１の回転圧縮要素３２（１段目）及び第２の回転圧縮要素３４（２段目）からなる回転圧縮機構部１８にて構成されている。
【００１９】
密閉容器１２は底部をオイル溜めとし、電動要素１４と回転圧縮機構部１８を収納する容器本体１２Ａと、この容器本体１２Ａの上部開口を閉塞する略椀状のエンドキャップ（蓋体）１２Ｂとで構成され、且つ、このエンドキャップ１２Ｂの上面中心には円形の取付孔１２Ｄが形成されており、この取付孔１２Ｄには電動要素１４に電力を供給するためのターミナル（配線を省略）２０が取り付けられている。
【００２０】
電動要素１４は、密閉容器１２の上部空間の内周面に沿って環状に取り付けられたステータ２２と、このステータ２２の内側に若干の間隔を設けて挿入設置されたロータ２４とからなる。このロータ２４は中心を通り鉛直方向に延びる回転軸１６に固定されている。
【００２１】
ステータ２２は、ドーナッツ状の電磁鋼板を積層した積層体２６と、この積層体２６の歯部に直巻き（集中巻き）方式により巻装されたステータコイル２８を有している。また、ロータ２４はステータ２２と同様に電磁鋼板の積層体３０で形成され、この積層体３０内に永久磁石ＭＧを挿入して形成されている。
【００２２】
前記第１の回転圧縮要素３２と第２の回転圧縮要素３４との間には中間仕切板３６が挟持されている。即ち、第１の回転圧縮要素３２と第２の回転圧縮要素３４は、中間仕切板３６と、この中間仕切板３６の上下に配置された上シリンダ３８、下シリンダ４０と、この上下シリンダ３８、４０内を、１８０度の位相差を有して回転軸１６に設けた上下偏心部４２、４４により偏心回転する上下ローラ４６、４８と、この上下ローラ４６、４８に当接して上下シリンダ３８、４０内をそれぞれ低圧室側と高圧室側に区画するベーン５０、５２と、上シリンダ３８の上側の開口面及び下シリンダ４０の下側の開口面を閉塞して回転軸１６の軸受けを兼用する支持部材としての上部支持部材５４及び下部支持部材５６にて構成されている。
【００２３】
一方、上部支持部材５４及び下部支持部材５６には、図示しない吸込ポートにて上下シリンダ３８、４０の内部とそれぞれ連通する吸込通路６０（上部支持部材５４側の吸込通路は図示せず）と、一部を凹陥させ、この凹陥部を上カバー６６、下カバー６８にて閉塞することにより形成される吐出消音室６２、６４とが設けられている。
【００２４】
尚、吐出消音室６４と密閉容器１２内とは、上下シリンダ３８、４０や中間仕切板３６を貫通する図示しない連通路にて連通されており、連通路の上端には中間吐出管１２１が立設され、この中間吐出管１２１から第１の回転圧縮要素３２で圧縮された中間圧の冷媒が密閉容器１２内に吐出される。また、第２の回転圧縮要素３４の上シリンダ３８内部と連通する吐出消音室６２の上面開口部を閉塞する上カバー６６は、密閉容器１２内を吐出消音室６２と電動要素１４側とに仕切る。
【００２５】
そして、この場合冷媒としては地球環境にやさしく、可燃性及び毒性等を考慮して自然冷媒である前述した二酸化炭素（ＣＯ2）を使用し、潤滑油としてのオイルは、例えば鉱物油（ミネラルオイル）、アルキルベンゼン油、エーテル油、エステル油、ＰＡＧ（ポリアルキルグリコール）等既存のオイルが使用される。
【００２６】
密閉容器１２を構成する容器本体１２Ａの側面には、上部支持部材５４と下部支持部材５６の吸込通路６０（上側は図示せず）、吐出消音室６２、上カバー６６の上側（電動要素１４の下端に略対応する位置）に対応する位置に、スリーブ１４１、１４２、１４３及び１４４がそれぞれ溶接固定されている。スリーブ１４１と１４２は上下に隣接すると共に、スリーブ１４３はスリーブ１４１の略対角線上にある。また、スリーブ１４４はスリーブ１４１と略９０度ずれた位置にある。
【００２７】
そして、スリーブ１４１内には上シリンダ３８に冷媒ガスを導入するための冷媒導入管９２の一端が挿入接続され、この冷媒導入管９２の一端は上シリンダ３８の図示しない吸込通路と連通する。この冷媒導入管９２は密閉容器１２の上側を通過してスリーブ１４４に至り、他端はスリーブ１４４内に挿入接続されて密閉容器１２内に連通する。
【００２８】
また、スリーブ１４２内には下シリンダ４０に冷媒ガスを導入するための冷媒導入管９４の一端が挿入接続され、この冷媒導入管９４の一端は下シリンダ４０の吸込通路６０と連通する。この冷媒導入管９４の他端は内部熱交換器１６０の出口に接続される。また、スリーブ１４３内には冷媒吐出管９６が挿入接続され、この冷媒吐出管９６の一端は吐出消音室６２と連通する。
【００２９】
次に、図２は本発明の遷臨界冷媒サイクル装置をカーエアコン（空気調和機）に適用した場合の冷媒回路を示しており、上述したロータリコンプレッサ１０は図２に示すカーエアコンの冷媒回路の一部を構成する。即ち、ロータリコンプレッサ１０の冷媒吐出管９６はガスクーラ１５４の入口に接続される。このガスクーラ１５４を出た配管は内部熱交換器１６０を介して電動式の膨張弁１５６（減圧装置）を経て、エバポレータ（蒸発器）１５７の入口に至り、エバポレータ１５７の出口は内部熱交換器１６０を介して冷媒導入管９４に接続される。
【００３０】
また、図２中１０２は制御装置としての汎用マイクロコンピュータから成るコントローラであり、１０３は冷媒導入管９４に取り付けられた温度センサである。また、１０４は冷媒吐出管９６に取り付けられた温度センサである。冷媒導入管９４にはロータリコンプレッサ１０の第１の回転圧縮要素３２に吸い込まれる冷媒が通過する。温度センサ１０３はこの吸込冷媒の温度（吸込側冷媒温度）を検出する。
【００３１】
一方、温度センサ１０４は冷媒吐出管９６を通過する冷媒ガスの温度、即ち、ロータリコンプレッサ１０の第２の回転圧縮要素３４の吐出側冷媒温度を検出する。また、１０５はガスクーラ１５４の出口側に設けられた圧力センサであり、高圧側冷媒圧力を検出する。また、１０６はエバポレータ１５７に取り付けられた温度センサであり、エバポレータ１５７における冷媒の蒸発温度を検出する。
【００３２】
これら温度センサ１０３、１０４、１０６及び圧力センサ１０５の出力はコントローラ１０２に入力されている。そして、コントローラ１０２はこれらセンサ１０３〜１０６の出力に基づき、前記ロータリコンプレッサ１０（の電動要素１４）の回転数（Ｈｚ）を制御するものである。
【００３３】
以上の構成で次に図３乃至図５を参照しながら動作を説明する。コントローラ１０２はターミナル２０及び図示しない配線を介して電動要素１４のステータコイル２８に通電し、電動要素１４を起動してロータ２４を回転させる。この起動時の回転数制御については後述するが、コントローラ１０２は停止状態から起動して最終的に起動時目標回転数まで電動要素１４の回転数を上昇させていくことになる。
【００３４】
ロータ２４の回転により回転軸１６と一体に設けた上下偏心部４２、４４に嵌合された上下ローラ４６、４８が上下シリンダ３８、４０内を偏心回転する。これにより、冷媒導入管９４及び下部支持部材５６に形成された吸込通路６０を経由して図示しない吸込ポートからシリンダ４０の低圧室側（定常運転時の圧力は４ＭＰａＧ程）に吸入された低圧の冷媒は、ローラ４８とベーン５２の動作により圧縮されて中間圧となり、下シリンダ４０の高圧室側より図示しない連通路を経て中間吐出管１２１から密閉容器１２内に吐出される。これによって、密閉容器１２内は中間圧（定常運転時の圧力は８ＭＰａＧ程）となる。
【００３５】
そして、密閉容器１２内の中間圧の冷媒ガスは、スリーブ１４４から出て冷媒導入管９２及び上部支持部材５４に形成された図示しない吸込通路を経由して図示しない吸込ポートから上シリンダ３８の低圧室側に吸入される。吸入された中間圧の冷媒ガスは、ローラ４６とベーン５０の動作により２段目の圧縮が行なわれて高圧高温（定常運転時の圧力は１２ＭＰａＧ程）の冷媒ガスとなり、高圧室側から図示しない吐出ポートを通り上部支持部材５４に形成された吐出消音室６２、冷媒吐出管９６を経由してガスクーラ１５４で放熱された後、内部熱交換器１６０を通過する。この高圧側では冷媒は超臨界状態の圧力となっており、ガスクーラ１５４及び内部熱交換器１６０で冷媒は凝縮せずガス状態のままである。
【００３６】
ガスクーラ１５４から出た高圧側冷媒はこの内部熱交換器１６０において後述するエバポレータ１５７から出た低圧側冷媒により冷却される。そして、この内部熱交換器１６０から出た高圧側冷媒は膨張弁１５６で絞られ（減圧され）、その過程で液化してエバポレータ１５７内に流入する。
【００３７】
このエバポレータ１５７内で冷媒は蒸発し、そのときに周囲から吸熱することにより冷却作用を発揮して車室内が冷房されることになる。このエバポレータ１５７から出た低圧側冷媒は内部熱交換器１６０に入る。この内部熱交換器１６０において、低圧側冷媒は前述の如くガスクーラ１５４から出た高圧側冷媒により加熱される。これにより、低圧側冷媒に所定の過熱度をとり、液冷媒がロータリコンプレッサ１０に吸い込まれることを防ぐ。その後、低圧側冷媒は内部熱交換器１６０から出て冷媒導入管９４を通り、ロータリコンプレッサ１０の第１の回転圧縮要素３２内に吸い込まれるサイクルを繰り返す。
【００３８】
次に、図３を用いてコントローラ１０２によるロータリコンプレッサ１０の起動時の電動要素１４の回転数制御について説明する。前述の如くロータリコンプレッサ１０の起動時にはコントローラ１０２は停止状態から電動要素１４の回転数を起動時目標回転数まで上昇させていく（図３にＬ１で示す）。このロータリコンプレッサ１０の起動によって温度センサ１０４が検出する吐出側冷媒温度も上昇していくが（図３にＬ２で示す）、吐出側冷媒温度の所定の下限温度と上限温度との間の所定範囲に設定されたＨｚアップ禁止温度帯（図３中ハッチングで示す）を通過する間は、電動要素１４の回転数上昇を禁止して下限温度に達したときの回転数を維持する。
【００３９】
尚、状況によっては回転数を徐々に下げてもよい）。そして、上限温度を超えた時点で、コントローラ１０２は再び電動要素１４の回転数を上昇させていく制御を実行する。
【００４０】
ここで、ロータリコンプレッサ１０の起動後、その回転数を上昇させていく過程では、吐出側冷媒温度（Ｌ２）も徐々に上昇していくことから、内部熱交換器１６０に入るガスクーラ１５４から出た高圧側冷媒の温度、即ち、内部熱交換器１６０の高圧側冷媒温度も比較的低い状態である。従って、内部熱交換器１６０において高圧側冷媒が低圧側冷媒を加熱する能力が低いので、そのまま電動要素１４の回転数を上昇させ、ロータリコンプレッサ１０に吸い込む低圧側冷媒の量を増やしていくと、内部熱交換器１６０における加熱能力が不足し、低圧側冷媒の過熱度がとれなくなってくる。
【００４１】
このような状態に陥ると、ロータリコンプレッサ１０の第１の回転圧縮要素３２には冷媒導入管９４から液冷媒が吸い込まれるようになり、回転圧縮機構部１８に損傷が生じてしまう。
【００４２】
そこで、実施例では温度センサ１０４が検出する吐出側冷媒温度を、内部熱交換器１６０の高圧側冷媒温度を示す指標として用い、上述のＨｚアップ禁止温度帯では電動要素１４の回転数上昇を禁止する（即ち、回転数を維持する。若しくは、低下させる。）ことで、係る高圧側冷媒の加熱能力不足時に、低圧側冷媒の吸込量を削減して液圧縮を防止している。
【００４３】
ここで、係るロータリコンプレッサ１０の起動時、コントローラ１０２は圧力センサ１０５が検出する高圧側冷媒の圧力を監視している。即ち、二酸化炭素を冷媒として用いた冷媒回路では、高圧側の圧力は前述した如く極めて高い値となる。そこで、コントローラ１０２は圧力センサ１０５が検出する高圧側冷媒の圧力が所定の既定値（耐圧限界に十分余裕をもった圧力）まで上昇した場合にも、電動要素１４の回転数上昇を禁止し、或いは、回転数を低下させる。そして、圧力が既定値より低下した時点で再び回転数上昇を再開する制御を実行し、装置の耐久性と安全性を維持する。
【００４４】
次に、車室内が或る程度冷えてくると、コントローラ１０２によるロータリコンプレッサ１０の制御は定常運転状態となってくる。そして、コントローラ１０２は消費電力削減のために、図４にＬ３で示すように電動要素１４の回転数を低下させていく方向の制御を実行する。この回転数を低下させていく過程では、吐出側冷媒温度（Ｌ４）も低下するので、内部熱交換器１６０に入るガスクーラ１５４から出た高圧側冷媒の温度、即ち、内部熱交換器１６０の高圧側冷媒温度も低下していく。従って、内部熱交換器１６０において高圧側冷媒が低圧側冷媒を加熱する能力も低下するので、そのまま電動要素１４の回転数を低下させていくと、内部熱交換器１６０における加熱能力が不足し、低圧側冷媒の過熱度がとれなくなってくる。
【００４５】
このような状態に陥ると、前述同様にロータリコンプレッサ１０の第１の回転圧縮要素３２には冷媒導入管９４から液冷媒が吸い込まれるようになり、回転圧縮機構部１８に損傷が生じてしまう。
【００４６】
そこで、実施例では温度センサ１０４が検出する吐出側冷媒温度を、内部熱交換器１６０の高圧側冷媒温度を示す指標として用い、吐出側冷媒温度の所定の下限温度と上限温度との間の所定範囲に設定されたＨｚダウン禁止温度帯（図４中ハッチングで示す）を通過する間は、電動要素１４の回転数低下を禁止して上限温度に達したときの回転数を維持する。尚、状況によっては回転数を徐々に上昇させてもよい）。そして、下限温度を超えた時点で、コントローラ１０２は再び電動要素１４の回転数を低下させていく制御を実行する。
【００４７】
このように、Ｈｚダウン禁止温度帯では電動要素１４の回転数低下を禁止する（即ち、回転数を維持する。若しくは、上昇させる。）ことで、係る高圧側冷媒の加熱能力の低下を中断させ、液圧縮の発生を防止する。
【００４８】
図５は係るＨｚダウン禁止温度帯の上限温度と下限温度をエバポレータ１５７における冷媒の蒸発温度に基づいて補正する方法を示している。即ち、エバポレータ１５７における冷媒の蒸発温度が低い場合には内部熱交換器１６０に入る低圧側冷媒の温度も低く、蒸発温度が高い場合には低圧側冷媒の温度も高いものと考えられる。
【００４９】
そこで、上記Ｈｚダウン禁止温度帯の上限温度と下限温度を、温度センサ１０６が検出するエバポレータ１５７の冷媒蒸発温度に比例して変化させる。この比例関係は、上限温度に上限基準温度、下限温度に下限基準温度を設定し、上限温度＝上限基準温度＋蒸発温度×α、下限温度＝下限基準温度＋蒸発温度×α’で規定する。尚、この比例乗数（傾き）αとα’同一でもよく、近似した値でもよい。
【００５０】
このようにＨｚダウン禁止温度帯を補正することで、例えば蒸発温度が低い状況では禁止温度帯を低い方向にシフトし、吐出側冷媒温度がより低いところで回転数の低下を禁止すると共に、蒸発温度が高い状況では禁止温度帯を高い方向にシフトし、吐出側冷媒温度がより高いところで回転数の低下を禁止して液圧縮を的確に防止する。
【００５１】
尚、図４に示すようにその後ロータリコンプレッサ１０の電動要素１４の回転数を上昇させていく過程においてもＨｚダウン禁止温度帯内では回転数の上昇を禁止する（この場合、Ｈｚアップ禁止温度帯とＨｚダウン禁止温度帯は同一）。これにより、定常運転時において電動要素１４の回転数を上昇させていく過程において生じる液圧縮も図３の起動時の場合と同様に回避できる。
【００５２】
また、図５の例ではＨｚダウン禁止温度帯の補正のみ示したが、それに限らず、図３のＨｚアップ禁止温度帯についても蒸発温度に応じて補正を行うとよい。その場合も図５と同様に蒸発温度が高い状態では禁止温度帯を高い方向にシフトし、蒸発温度が低い状態では禁止温度帯を低い方向にシフトすることで、起動時の回転数上昇をできるだけ迅速化できる。
【００５３】
更に、上記実施例では内部熱交換器１６０の高圧側冷媒温度を示す指標として温度センサ１０４が検出する吐出側冷媒温度を用いたが、内部熱交換器１６０の高圧側冷媒温度は高圧側圧力にも左右されるので、圧力センサ１０５が検出する高圧側圧力を指標として用いてもよい。
【００５４】
更にまた、上記実施例では内部熱交換器１６０の高圧側冷媒温度を用いたが、内部熱交換器１６０の低圧側冷媒温度を示す指標に基づいて電動要素１４の回転数制御を実行してもよい。その場合には、温度センサ１０３が検出する吸込側冷媒温度が指標となる。そして、例えば起動時には、係る吸込側冷媒温度が低下していく過程の所定範囲をＨｚアップ禁止温度帯として前述同様の制御を行うと共に、定常運転時には吸込側冷媒温度が上昇していく過程の所定範囲をＨｚダウン禁止温度帯として前述同様の制御を実行する。
【００５５】
係る内部熱交換器１６０の低圧側冷媒の温度によっても、ロータリコンプレッサ１０の液圧縮を的確に防止することができる。
【００５６】
ここで、内部熱交換器１６０の高圧側冷媒温度及び内部熱交換器１６０の低圧側冷媒温度を示す指標としては上述した実施例のものに限らず、冷媒回路内の温度・圧力その他のあらゆる情報が指標と成り得ることは云うまでもない。また、上述した温度帯の上限温度／下限温度、それらの基準温度や傾きは冷媒サイクル装置やロータリコンプレッサの能力／容量に応じて適宜設定するものとする。
【００５７】
【発明の効果】
以上詳述した如く請求項１の発明によれば、圧縮機の回転数を制御する制御装置により、内部熱交換器の高圧側冷媒温度、若しくは、当該内部熱交換器の低圧側冷媒温度を示す指標に基づき、圧縮機の回転数を制御すると共に、前記圧縮機の回転数を上昇させる過程において、指標の所定範囲内で当該圧縮機の回転数上昇を禁止し、若しくは、回転数を低下させるので、圧縮機の回転数を上昇させていく過程で内部熱交換器における高圧側冷媒による低圧側冷媒の加熱能力が不足することによる圧縮機の液圧縮の発生を未然に回避することが可能となる。また、高圧側の圧力が異常に上昇する不都合も回避できるので、信頼性も向上する。
【００５８】
特に、請求項２の如く高圧側冷媒の圧力が上昇した場合、圧縮機の回転数上昇を禁止し、若しくは、回転数を低下させ、或いは、当該圧縮機を停止させれば、起動時における高圧側圧力の異常上昇を確実に防止できるようになる。これは特に請求項５の如く圧力が高くなる二酸化炭素を冷媒として使用する場合には極めて有効となる。
【００５９】
請求項３の発明によれば、圧縮機の回転数を制御する制御装置により、内部熱交換器の高圧側冷媒温度、若しくは、当該内部熱交換器の低圧側冷媒温度を示す指標に基づき、圧縮機の回転数を制御すると共に、圧縮機の回転数を低下させる過程において、指標の所定範囲内で当該圧縮機の回転数低下を禁止し、若しくは、回転数を上昇させるので、圧縮機の回転数を低下させていく過程で内部熱交換器における高圧側冷媒による低圧側冷媒の加熱能力が不足することによる圧縮機の液圧縮を回避することができるようになる。
【００６０】
請求項４の発明によれば、圧縮機の回転数を制御する制御装置により、内部熱交換器の高圧側冷媒温度、若しくは、当該内部熱交換器の低圧側冷媒温度を示す指標に基づき、圧縮機の回転数を制御すると共に、圧縮機の回転数を上昇させる過程において、指標の所定範囲内で当該圧縮機の回転数上昇を禁止し、若しくは、回転数を低下させ、圧縮機の回転数を低下させる過程においては、指標の所定範囲内で当該圧縮機の回転数低下を禁止し、若しくは、回転数を上昇させるので、圧縮機の回転数を上昇させていく過程で内部熱交換器における高圧側冷媒による低圧側冷媒の加熱能力が不足することによる圧縮機の液圧縮の発生を未然に回避することが可能となる。また、高圧側の圧力が異常に上昇する不都合も回避できるので、信頼性も向上する。
【００６１】
更に、圧縮機の回転数を低下させていく過程で内部熱交換器における高圧側冷媒による低圧側冷媒の加熱能力が不足することによる圧縮機の液圧縮を回避することができるようになる。
【００６２】
また、上記各発明において、圧縮機の吐出側冷媒温度や吸込側冷媒温度を前記指標とすれば、内部熱交換器に入る高圧側冷媒の温度、若しくは、当該内部熱交換器を出た低圧側冷媒の温度を的確に判断できる。
【００６３】
特に、蒸発器における冷媒の蒸発温度に基づいて圧縮機の吐出側冷媒温度から得られた前記指標の所定範囲を補正すれば、より的確な圧縮機の回転数制御による液圧縮の防止を行うことができるようになる。
【００６４】
また、圧縮機の吸込側冷媒温度から前記指標を得る場合にはガスクーラ出口における冷媒の温度に基づいて前記指標の所定範囲を補正することでも圧縮機の回転数上昇を迅速に行いながら圧縮機の液圧縮を防止できるようになる。
【００６５】
上記各発明は、特に請求項５の如く圧力が高くなる二酸化炭素を冷媒として使用する場合には極めて有効となる。
【図面の簡単な説明】
【図１】 本発明の実施例の遷臨界冷媒サイクル装置を構成する内部中間圧型２段圧縮式ロータリコンプレッサの縦断面図である。
【図２】 本発明の遷臨界冷媒サイクル装置の実施例のカーエアコンの冷媒回路図である。
【図３】 本発明の遷臨界冷媒サイクル装置のコントローラによるロータリコンプレッサの起動時の回転数制御を示す図である。
【図４】 本発明の遷臨界冷媒サイクル装置のコントローラによるロータリコンプレッサの定常運転時の回転数制御を示す図である。
【図５】 図４の回転数制御におけるＨｚダウン禁止温度帯の補正方法を示す図である。
【符号の説明】
１０ ロータリコンプレッサ
１４ 電動要素
３２ 第１の回転圧縮要素
３４ 第２の回転圧縮要素
１０２ コントローラ（制御装置）
１０３、１０４、１０６ 温度センサ
１０５ 圧力センサ
１５４ ガスクーラ
１５６ 膨張弁（減圧装置）
１５７ エバポレータ（蒸発器）
１６０ 内部熱交換器[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a transcritical refrigerant cycle device in which a compressor, a gas cooler, a decompression device, and an evaporator are sequentially connected in a pipe and the high pressure side becomes a supercritical pressure.
[0002]
[Prior art]
  In order to solve the global environmental destruction problem in recent years, the use of CFC-based refrigerants with a high risk of ozone layer destruction is also prohibited or regulated in this kind of refrigerant cycle apparatus for refrigeration / air conditioning. Therefore, a refrigerant cycle apparatus using carbon dioxide, which is one of natural refrigerants, has been developed (see, for example, Patent Document 1). When such a natural substance such as carbon dioxide is used as a refrigerant, the critical temperature is extremely low, so that the high pressure side does not become less than the critical pressure and is operated exclusively at the supercritical pressure.
[0003]
[Patent Document 1]
          Japanese Patent Publication No. 7-18602
[0004]
  By the way, in such a refrigerant cycle device, an internal heat exchanger is used to promote heat dissipation of the refrigerant on the high pressure side and to superheat the refrigerant on the low pressure side. This internal heat exchanger exchanges heat between the high-pressure side refrigerant that has exited the gas cooler of the refrigerant cycle device and the low-pressure side refrigerant that has exited the evaporator, lowers the temperature of the high-pressure side refrigerant entering the decompression device, and Take the superheat of the low-pressure refrigerant sucked. Thereby, the inconvenience that the liquid refrigerant is sucked into the compressor without providing an accumulator can be avoided.
[0005]
[Problems to be solved by the invention]
  However, for example, in the stage where the temperature of the high-pressure side refrigerant is still not high in the process of increasing the rotation speed after starting the compressor, the compressor is sucked into the compressor through the internal heat exchanger in a certain rotation speed range. A situation occurs in which the heating capability of the high-pressure side refrigerant in the internal heat exchanger for the low-pressure side refrigerant is insufficient.
[0006]
  The same occurs in the process of increasing the rotational speed of the compressor during steady operation and the process of decreasing the rotational speed of the compressor. That is, when the rotation speed of the compressor is decreased, the heating capability of the high-pressure side refrigerant in the internal heat exchanger with respect to the low-pressure side refrigerant is also decreased. In such a situation, a sufficient degree of superheat of the low-pressure side refrigerant cannot be obtained, and a problem arises that so-called liquid compression occurs because the liquid refrigerant is sucked into the compressor.
[0007]
  The present invention has been made to solve the conventional technical problem, and in a transcritical refrigerant cycle apparatus having an internal heat exchanger, when the rotational speed of the compressor is increased or decreased. The purpose is to effectively prevent the liquid compression of the compressor that occurs in the above.
[0008]
[Means for Solving the Problems]
  That is,Claim 1In the invention, an internal heat exchanger for exchanging heat between a high-pressure side refrigerant coming out of a gas cooler and a low-pressure side refrigerant coming out of an evaporator, comprising a compressor, a gas cooler, a pressure reducing device, and an evaporator connected in an annular manner in order. And a control device that controls the number of rotations of the compressor in the transcritical refrigerant cycle device in which the high pressure side is at the supercritical pressure, the control device includes the high pressure side refrigerant temperature of the internal heat exchanger or the internal heat Controls the rotation speed of the compressor based on the index indicating the low-pressure side refrigerant temperature of the exchangerAt the same time, in the process of increasing the rotation speed of the compressor, the increase in the rotation speed of the compressor is prohibited within a predetermined range of the index, or the rotation speed is decreased.In the process of increasing the number of rotations of the compressor, it is possible to avoid the occurrence of liquid compression of the compressor due to insufficient heating capability of the low-pressure side refrigerant by the high-pressure side refrigerant in the internal heat exchanger. Moreover, since the inconvenience that the pressure on the high-pressure side abnormally increases can be avoided, the reliability is also improved.
[0009]
  In particular,As in claim 2If the pressure of the high-pressure side refrigerant rises, prohibiting an increase in the rotational speed of the compressor, or reducing the rotational speed, or stopping the compressor will ensure an abnormal increase in the high-pressure side pressure at startup. Will be able to prevent. This is extremely effective particularly when carbon dioxide having a high pressure is used as a refrigerant as in the fifth aspect.
[0010]
  In the invention of claim 3, a compressor, a gas cooler, a pressure reducing device, and an evaporator are sequentially connected in an annular manner to exchange heat between the high-pressure refrigerant discharged from the gas cooler and the low-pressure refrigerant discharged from the evaporator. In a transcritical refrigerant cycle apparatus that includes an internal heat exchanger and has a supercritical pressure on the high pressure side, the controller includes a control device that controls the rotational speed of the compressor, the control device includes a high pressure side refrigerant temperature of the internal heat exchanger, or In the process of controlling the rotational speed of the compressor and reducing the rotational speed of the compressor based on the index indicating the low-pressure side refrigerant temperature of the internal heat exchanger, it is within the predetermined range of the index. Since the reduction in the rotational speed of the compressor is prohibited or the rotational speed is increased, the ability to heat the low-pressure side refrigerant by the high-pressure side refrigerant in the internal heat exchanger is insufficient in the process of decreasing the rotational speed of the compressor. This makes it possible to avoid liquid compression of the compressor.
[0011]
  In the invention of claim 4, a compressor, a gas cooler, a pressure reducing device, and an evaporator are sequentially connected in an annular manner to exchange heat between the high-pressure side refrigerant discharged from the gas cooler and the low-pressure side refrigerant discharged from the evaporator. In a transcritical refrigerant cycle apparatus that includes an internal heat exchanger and has a supercritical pressure on the high pressure side, the controller includes a control device that controls the rotational speed of the compressor, the control device includes a high pressure side refrigerant temperature of the internal heat exchanger, or In the process of controlling the rotational speed of the compressor and increasing the rotational speed of the compressor based on the index indicating the low-pressure side refrigerant temperature of the internal heat exchanger, the rotational speed of the compressor within the predetermined range of the index In the process of prohibiting the increase or decreasing the rotation speed and decreasing the rotation speed of the compressor, the decrease in the rotation speed of the compressor is prohibited within the predetermined range of the index or the rotation speed is increased. ,compression And it is possible to avoid in advance the occurrence of the compressor liquid compression due to insufficient heating capacity of the low-pressure refrigerant by the high-pressure side refrigerant in the internal heat exchanger in the process of gradually increasing the rotational speed. Moreover, since the inconvenience that the pressure on the high-pressure side abnormally increases can be avoided, the reliability is also improved.
[0012]
  Further, it is possible to avoid liquid compression of the compressor due to insufficient heating ability of the low-pressure side refrigerant by the high-pressure side refrigerant in the internal heat exchanger in the process of decreasing the rotational speed of the compressor.
[0013]
  Also,In each of the above inventions,If the discharge side refrigerant temperature or the suction side refrigerant temperature of the compressor is used as the index, the temperature of the high-pressure side refrigerant entering the internal heat exchanger or the temperature of the low-pressure side refrigerant exiting the internal heat exchanger is accurately determined. it can.
[0014]
  In particular, if the predetermined range of the index obtained from the refrigerant temperature on the discharge side of the compressor is corrected based on the evaporation temperature of the refrigerant in the evaporator, liquid compression can be prevented by more accurate compressor rotation speed control. Will be able to.
[0015]
  Further, when the index is obtained from the suction side refrigerant temperature of the compressor, the predetermined range of the index is corrected based on the refrigerant temperature at the outlet of the gas cooler, and the compressor speed is increased while the compressor speed is rapidly increased. Liquid compression can be prevented.
[0016]
  Each of the above inventionsThis is particularly effective when carbon dioxide having a high pressure is used as a refrigerant.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of a compressor used in the transcritical refrigerant cycle apparatus of the present invention, as an internal intermediate pressure type multi-stage having first and second rotary compression elements 32 and 34 (both are examples of compression elements). 2 is a longitudinal side view of a two-stage compression rotary compressor 10. FIG. In the transcritical refrigerant cycle device of the example, the high pressure side is the supercritical pressure.
[0018]
  In this figure, 10 is carbon dioxide (CO2) Is used as a refrigerant, and is an internal intermediate pressure type multi-stage compression rotary compressor (corresponding to the compressor of the present invention). The rotary compressor 10 includes a cylindrical sealed container 12 made of a steel plate and an upper side of the internal space of the sealed container 12. And the first rotary compression element 32 (first stage) and the second rotary compression element which are arranged below the electric element 14 and are driven by the rotating shaft 16 of the electric element 14. The rotary compression mechanism 18 is composed of 34 (second stage).
[0019]
  The sealed container 12 has an oil reservoir at the bottom, a container body 12A that houses the electric element 14 and the rotary compression mechanism 18, and a generally bowl-shaped end cap (lid body) 12B that closes the upper opening of the container body 12A. A circular mounting hole 12D is formed in the center of the upper surface of the end cap 12B, and a terminal (wiring is omitted) 20 for supplying power to the electric element 14 is mounted in the mounting hole 12D. It has been.
[0020]
  The electric element 14 includes a stator 22 attached in an annular shape along the inner peripheral surface of the upper space of the hermetic container 12, and a rotor 24 inserted and installed inside the stator 22 with a slight gap. The rotor 24 is fixed to a rotating shaft 16 that passes through the center and extends in the vertical direction.
[0021]
  The stator 22 has a laminated body 26 in which donut-shaped electromagnetic steel plates are laminated, and a stator coil 28 wound around the teeth of the laminated body 26 by a direct winding (concentrated winding) method. Similarly to the stator 22, the rotor 24 is formed of a laminated body 30 of electromagnetic steel plates, and is formed by inserting a permanent magnet MG into the laminated body 30.
[0022]
  An intermediate partition plate 36 is sandwiched between the first rotary compression element 32 and the second rotary compression element 34. That is, the first rotary compression element 32 and the second rotary compression element 34 include an intermediate partition plate 36, an upper cylinder 38 and a lower cylinder 40 disposed above and below the intermediate partition plate 36, and the upper and lower cylinders 38, 40, the upper and lower rollers 46 and 48 that are eccentrically rotated by the upper and lower eccentric portions 42 and 44 provided on the rotary shaft 16 with a phase difference of 180 degrees, and the upper and lower cylinders 38 and 48 in contact with the upper and lower rollers 46 and 48, The vanes 50 and 52 that divide the inside of the inside 40 into a low-pressure chamber side and a high-pressure chamber side, and the upper opening surface of the upper cylinder 38 and the lower opening surface of the lower cylinder 40 are closed to serve as bearings for the rotary shaft 16. The upper support member 54 and the lower support member 56 are used as support members.
[0023]
  On the other hand, in the upper support member 54 and the lower support member 56, a suction passage 60 (a suction passage on the upper support member 54 side is not shown) that communicates with the inside of the upper and lower cylinders 38 and 40 through a suction port (not shown), Discharge silencing chambers 62 and 64 are provided which are formed by recessing a part and closing the recess with an upper cover 66 and a lower cover 68.
[0024]
  The discharge silencing chamber 64 and the inside of the sealed container 12 are communicated with each other through a communication passage (not shown) that penetrates the upper and lower cylinders 38 and 40 and the intermediate partition plate 36, and an intermediate discharge pipe 121 stands at the upper end of the communication passage. The intermediate pressure refrigerant compressed by the first rotary compression element 32 is discharged from the intermediate discharge pipe 121 into the sealed container 12. An upper cover 66 that closes the upper opening of the discharge silencing chamber 62 that communicates with the inside of the upper cylinder 38 of the second rotary compression element 34 partitions the inside of the sealed container 12 into the discharge silencing chamber 62 and the electric element 14 side. .
[0025]
  In this case, the above-mentioned carbon dioxide (CO 2), which is a natural refrigerant in consideration of flammability and toxicity, is friendly to the global environment as the refrigerant.2As the lubricating oil, existing oils such as mineral oil (mineral oil), alkylbenzene oil, ether oil, ester oil, and PAG (polyalkyl glycol) are used.
[0026]
  A suction passage 60 (upper side is not shown) of the upper support member 54 and the lower support member 56, a discharge silencer chamber 62, and an upper side of the upper cover 66 (on the electric element 14) Sleeves 141, 142, 143, and 144 are welded and fixed at positions corresponding to the positions substantially corresponding to the lower ends. The sleeves 141 and 142 are adjacent to each other vertically, and the sleeve 143 is substantially diagonal to the sleeve 141. Further, the sleeve 144 is located at a position shifted by approximately 90 degrees from the sleeve 141.
[0027]
  One end of a refrigerant introduction pipe 92 for introducing refrigerant gas into the upper cylinder 38 is inserted and connected into the sleeve 141, and one end of the refrigerant introduction pipe 92 communicates with a suction passage (not shown) of the upper cylinder 38. The refrigerant introduction pipe 92 passes through the upper side of the sealed container 12 to reach the sleeve 144, and the other end is inserted and connected into the sleeve 144 to communicate with the sealed container 12.
[0028]
  In addition, one end of a refrigerant introduction pipe 94 for introducing refrigerant gas into the lower cylinder 40 is inserted and connected in the sleeve 142, and one end of the refrigerant introduction pipe 94 communicates with the suction passage 60 of the lower cylinder 40. The other end of the refrigerant introduction pipe 94 is connected to the outlet of the internal heat exchanger 160. In addition, a refrigerant discharge pipe 96 is inserted and connected into the sleeve 143, and one end of the refrigerant discharge pipe 96 communicates with the discharge silencer chamber 62.
[0029]
  Next, FIG. 2 shows a refrigerant circuit when the transcritical refrigerant cycle device of the present invention is applied to a car air conditioner (air conditioner), and the above-described rotary compressor 10 is the same as the refrigerant circuit of the car air conditioner shown in FIG. Part of it. That is, the refrigerant discharge pipe 96 of the rotary compressor 10 is connected to the inlet of the gas cooler 154. The piping that exits the gas cooler 154 passes through an internal heat exchanger 160 through an electric expansion valve 156 (decompression device), reaches an inlet of an evaporator (evaporator) 157, and the outlet of the evaporator 157 is connected to the internal heat exchanger 160. Is connected to the refrigerant introduction pipe 94 via
[0030]
  In FIG. 2, reference numeral 102 denotes a controller composed of a general-purpose microcomputer as a control device, and reference numeral 103 denotes a temperature sensor attached to the refrigerant introduction pipe 94. Reference numeral 104 denotes a temperature sensor attached to the refrigerant discharge pipe 96. The refrigerant sucked into the first rotary compression element 32 of the rotary compressor 10 passes through the refrigerant introduction pipe 94. The temperature sensor 103 detects the temperature of the suction refrigerant (suction side refrigerant temperature).
[0031]
  On the other hand, the temperature sensor 104 detects the temperature of the refrigerant gas passing through the refrigerant discharge pipe 96, that is, the discharge-side refrigerant temperature of the second rotary compression element 34 of the rotary compressor 10. Reference numeral 105 denotes a pressure sensor provided on the outlet side of the gas cooler 154, which detects the high-pressure side refrigerant pressure. Reference numeral 106 denotes a temperature sensor attached to the evaporator 157, which detects the evaporation temperature of the refrigerant in the evaporator 157.
[0032]
  The outputs of these temperature sensors 103, 104, 106 and pressure sensor 105 are input to the controller 102. The controller 102 controls the rotational speed (Hz) of the rotary compressor 10 (the electric element 14) based on the outputs of the sensors 103 to 106.
[0033]
  Next, the operation of the above configuration will be described with reference to FIGS. The controller 102 energizes the stator coil 28 of the electric element 14 via the terminal 20 and a wiring (not shown), and activates the electric element 14 to rotate the rotor 24. Although the rotation speed control at the time of activation will be described later, the controller 102 is activated from the stop state and finally increases the rotation speed of the electric element 14 to the activation target rotation speed.
[0034]
  As the rotor 24 rotates, the upper and lower rollers 46 and 48 fitted to the upper and lower eccentric portions 42 and 44 provided integrally with the rotary shaft 16 eccentrically rotate in the upper and lower cylinders 38 and 40. As a result, the low pressure suctioned from the suction port (not shown) to the low pressure chamber side of the cylinder 40 (the pressure during steady operation is about 4 MPaG) via the suction passage 60 formed in the refrigerant introduction pipe 94 and the lower support member 56. The refrigerant is compressed by the operation of the roller 48 and the vane 52 to become an intermediate pressure, and is discharged from the intermediate discharge pipe 121 into the sealed container 12 through a communication path (not shown) from the high pressure chamber side of the lower cylinder 40. As a result, the inside of the sealed container 12 has an intermediate pressure (the pressure during steady operation is about 8 MPaG).
[0035]
  The intermediate-pressure refrigerant gas in the sealed container 12 exits from the sleeve 144 and passes through a suction passage (not shown) formed in the refrigerant introduction pipe 92 and the upper support member 54, and then the low pressure of the upper cylinder 38 from the suction port (not shown). Inhaled into the room. The suctioned intermediate-pressure refrigerant gas is compressed in the second stage by the operation of the roller 46 and the vane 50 to become high-pressure and high-temperature refrigerant gas (pressure during steady operation is about 12 MPaG), and is not shown from the high-pressure chamber side. The heat is radiated from the gas cooler 154 through the discharge silencer chamber 62 formed in the upper support member 54 and the refrigerant discharge pipe 96 through the discharge port, and then passes through the internal heat exchanger 160. On this high pressure side, the refrigerant has a supercritical pressure, and the refrigerant does not condense in the gas cooler 154 and the internal heat exchanger 160 and remains in a gas state.
[0036]
  The high-pressure refrigerant discharged from the gas cooler 154 is cooled by the low-pressure refrigerant discharged from an evaporator 157 described later in the internal heat exchanger 160. The high-pressure refrigerant discharged from the internal heat exchanger 160 is throttled (depressurized) by the expansion valve 156, liquefied in the process, and flows into the evaporator 157.
[0037]
  In this evaporator 157, the refrigerant evaporates, and at that time, the refrigerant absorbs heat from the surroundings, thereby exhibiting a cooling action and cooling the passenger compartment. The low-pressure side refrigerant that has exited from the evaporator 157 enters the internal heat exchanger 160. In the internal heat exchanger 160, the low-pressure side refrigerant is heated by the high-pressure side refrigerant discharged from the gas cooler 154 as described above. As a result, a predetermined degree of superheat is applied to the low-pressure side refrigerant, and the liquid refrigerant is prevented from being sucked into the rotary compressor 10. Thereafter, the low-pressure side refrigerant leaves the internal heat exchanger 160, passes through the refrigerant introduction pipe 94, and repeats the cycle of being sucked into the first rotary compression element 32 of the rotary compressor 10.
[0038]
  Next, the rotation speed control of the electric element 14 when the rotary compressor 10 is started by the controller 102 will be described with reference to FIG. As described above, when the rotary compressor 10 is started, the controller 102 increases the rotational speed of the electric element 14 from the stopped state to the target rotational speed at startup (indicated by L1 in FIG. 3). Although the discharge-side refrigerant temperature detected by the temperature sensor 104 is increased by the activation of the rotary compressor 10 (indicated by L2 in FIG. 3), a predetermined range between a predetermined lower limit temperature and an upper limit temperature of the discharge side refrigerant temperature. During the passage of the Hz up prohibition temperature zone (indicated by hatching in FIG. 3) set to, the increase in the rotation speed of the electric element 14 is prohibited and the rotation speed when the lower limit temperature is reached is maintained.
[0039]
  Depending on the situation, the rotational speed may be gradually reduced). When the upper limit temperature is exceeded, the controller 102 executes control to increase the rotational speed of the electric element 14 again.
[0040]
  Here, in the process of increasing the rotational speed after the rotary compressor 10 is started, the discharge-side refrigerant temperature (L2) also gradually increases, so that the gas cooler 154 entering the internal heat exchanger 160 exits. The temperature of the high-pressure side refrigerant, that is, the high-pressure side refrigerant temperature of the internal heat exchanger 160 is also relatively low. Therefore, since the high-pressure side refrigerant has a low ability to heat the low-pressure side refrigerant in the internal heat exchanger 160, if the number of low-pressure side refrigerant sucked into the rotary compressor 10 is increased by increasing the rotational speed of the electric element 14 as it is, The heating capacity in the internal heat exchanger 160 is insufficient, and the degree of superheat of the low-pressure side refrigerant cannot be obtained.
[0041]
  In such a state, the liquid refrigerant is sucked into the first rotary compression element 32 of the rotary compressor 10 from the refrigerant introduction pipe 94, and the rotary compression mechanism 18 is damaged.
[0042]
  Therefore, in the embodiment, the discharge-side refrigerant temperature detected by the temperature sensor 104 is used as an index indicating the high-pressure side refrigerant temperature of the internal heat exchanger 160, and the increase in the rotational speed of the electric element 14 is prohibited in the above-described Hz-up prohibition temperature range. By doing (that is, maintaining or reducing the rotation speed), when the heating capacity of the high-pressure side refrigerant is insufficient, the suction amount of the low-pressure side refrigerant is reduced to prevent liquid compression.
[0043]
  Here, when the rotary compressor 10 is activated, the controller 102 monitors the pressure of the high-pressure side refrigerant detected by the pressure sensor 105. That is, in the refrigerant circuit using carbon dioxide as the refrigerant, the pressure on the high pressure side is extremely high as described above. Therefore, the controller 102 prohibits the increase in the rotational speed of the electric element 14 even when the pressure of the high-pressure refrigerant detected by the pressure sensor 105 has increased to a predetermined predetermined value (pressure having a sufficient margin for the pressure resistance limit). Alternatively, the rotational speed is decreased. Then, when the pressure drops below the predetermined value, the control for restarting the rotation speed increase is executed again to maintain the durability and safety of the apparatus.
[0044]
  Next, when the passenger compartment cools to some extent, the control of the rotary compressor 10 by the controller 102 becomes a steady operation state. And the controller 102 performs control of the direction which reduces the rotation speed of the electrically-driven element 14, as shown by L3 in FIG. 4 in order to reduce power consumption. In the process of decreasing the rotational speed, the discharge-side refrigerant temperature (L4) also decreases, so the temperature of the high-pressure side refrigerant exiting from the gas cooler 154 entering the internal heat exchanger 160, that is, the high pressure of the internal heat exchanger 160 The side refrigerant temperature also decreases. Accordingly, since the ability of the high-pressure side refrigerant to heat the low-pressure side refrigerant in the internal heat exchanger 160 also decreases, if the rotational speed of the electric element 14 is reduced as it is, the heating capacity in the internal heat exchanger 160 is insufficient, The superheat of the low-pressure side refrigerant cannot be removed.
[0045]
  In such a state, liquid refrigerant is sucked into the first rotary compression element 32 of the rotary compressor 10 from the refrigerant introduction pipe 94 as described above, and the rotary compression mechanism 18 is damaged.
[0046]
  Therefore, in the embodiment, the discharge side refrigerant temperature detected by the temperature sensor 104 is used as an index indicating the high pressure side refrigerant temperature of the internal heat exchanger 160, and a predetermined value between a predetermined lower limit temperature and an upper limit temperature of the discharge side refrigerant temperature. While passing the Hz down prohibition temperature zone set in the range (indicated by hatching in FIG. 4), the rotation speed when the electric element 14 reaches the upper limit temperature is maintained by prohibiting the decrease in the rotation speed of the electric element 14. Depending on the situation, the rotational speed may be gradually increased). Then, when the lower limit temperature is exceeded, the controller 102 executes control to reduce the rotational speed of the electric element 14 again.
[0047]
  Thus, in the Hz down prohibition temperature range, the reduction in the rotational speed of the electric element 14 is prohibited (that is, the rotational speed is maintained or increased), thereby interrupting the reduction in the heating capacity of the high-pressure refrigerant. Prevents liquid compression from occurring.
[0048]
  FIG. 5 shows a method of correcting the upper limit temperature and the lower limit temperature of the Hz down prohibition temperature zone based on the evaporation temperature of the refrigerant in the evaporator 157. That is, it is considered that when the evaporation temperature of the refrigerant in the evaporator 157 is low, the temperature of the low-pressure side refrigerant entering the internal heat exchanger 160 is low, and when the evaporation temperature is high, the temperature of the low-pressure side refrigerant is high.
[0049]
  Therefore, the upper limit temperature and the lower limit temperature of the Hz down prohibition temperature zone are changed in proportion to the refrigerant evaporation temperature of the evaporator 157 detected by the temperature sensor 106. This proportional relationship is defined by setting an upper limit reference temperature as the upper limit temperature and a lower limit reference temperature as the lower limit temperature, and upper limit temperature = upper reference temperature + evaporation temperature × α and lower limit temperature = lower limit reference temperature + evaporation temperature × α ′. The proportional multiplier (slope) α and α ′ may be the same or may be approximate values.
[0050]
  By correcting the Hz down prohibition temperature zone in this manner, for example, in a situation where the evaporation temperature is low, the prohibition temperature zone is shifted to a lower direction, and the decrease in the rotational speed is prohibited when the discharge side refrigerant temperature is lower, and the evaporation temperature When the temperature is high, the prohibition temperature zone is shifted to a higher direction, and when the discharge-side refrigerant temperature is higher, the decrease in the rotational speed is prohibited to prevent liquid compression accurately.
[0051]
  As shown in FIG. 4, even in the process of increasing the rotational speed of the electric element 14 of the rotary compressor 10 thereafter, the increase in the rotational speed is prohibited within the Hz down prohibited temperature range (in this case, the Hz up prohibited temperature range). And Hz down prohibition temperature zone are the same). Thereby, the liquid compression which arises in the process which raises the rotation speed of the electrically-driven element 14 at the time of steady operation can also be avoided similarly to the case at the time of starting of FIG.
[0052]
  In the example of FIG. 5, only correction of the Hz down prohibition temperature zone is shown, but not limited thereto, the Hz up prohibition temperature zone of FIG. 3 may be corrected according to the evaporation temperature. In this case as well, as in FIG. 5, the prohibition temperature zone is shifted to a higher direction when the evaporation temperature is high, and the prohibition temperature zone is shifted to a lower direction when the evaporation temperature is low, thereby increasing the rotational speed at startup as much as possible. Speed up.
[0053]
  Further, in the above embodiment, the discharge side refrigerant temperature detected by the temperature sensor 104 is used as an index indicating the high pressure side refrigerant temperature of the internal heat exchanger 160, but the high pressure side refrigerant temperature of the internal heat exchanger 160 is equal to the high pressure side pressure. Therefore, the high-pressure side pressure detected by the pressure sensor 105 may be used as an index.
[0054]
  Furthermore, in the above embodiment, the high-pressure side refrigerant temperature of the internal heat exchanger 160 is used. However, even if the rotational speed control of the electric element 14 is executed based on an index indicating the low-pressure side refrigerant temperature of the internal heat exchanger 160. Good. In that case, the suction side refrigerant temperature detected by the temperature sensor 103 serves as an index. For example, at the time of start-up, the predetermined range of the process in which the suction-side refrigerant temperature decreases is set to the Hz up-prohibited temperature range, and the same control as described above is performed. The same control as described above is executed with the range as the Hz down prohibition temperature zone.
[0055]
  The liquid compression of the rotary compressor 10 can be accurately prevented also by the temperature of the low-pressure side refrigerant of the internal heat exchanger 160.
[0056]
  Here, the index indicating the high-pressure side refrigerant temperature of the internal heat exchanger 160 and the low-pressure side refrigerant temperature of the internal heat exchanger 160 is not limited to that of the above-described embodiment, and any other information such as temperature / pressure in the refrigerant circuit. Needless to say, can be an indicator. In addition, the upper limit temperature / lower limit temperature of the above-described temperature zone, and the reference temperature and inclination thereof are appropriately set according to the capacity / capacity of the refrigerant cycle device and the rotary compressor.
[0057]
【The invention's effect】
  As detailed aboveClaim 1According to the invention, the number of rotations of the compressor is controlled based on the index indicating the high-pressure side refrigerant temperature of the internal heat exchanger or the low-pressure side refrigerant temperature of the internal heat exchanger by the control device that controls the rotation speed of the compressor. ControlAt the same time, in the process of increasing the rotation speed of the compressor, the increase in the rotation speed of the compressor is prohibited within a predetermined range of the index, or the rotation speed is decreased.In the process of increasing the number of rotations of the compressor, it is possible to avoid the occurrence of liquid compression of the compressor due to insufficient heating capability of the low-pressure side refrigerant by the high-pressure side refrigerant in the internal heat exchanger. Moreover, since the inconvenience that the pressure on the high-pressure side abnormally increases can be avoided, the reliability is also improved.
[0058]
  In particular,As in claim 2If the pressure of the high-pressure side refrigerant rises, prohibiting an increase in the rotational speed of the compressor, or reducing the rotational speed, or stopping the compressor will ensure an abnormal increase in the high-pressure side pressure at startup. Will be able to prevent. This is extremely effective particularly when carbon dioxide having a high pressure is used as a refrigerant as in the fifth aspect.
[0059]
  According to the invention of claim 3, the control device that controls the rotation speed of the compressor compresses based on the index indicating the high-pressure side refrigerant temperature of the internal heat exchanger or the low-pressure side refrigerant temperature of the internal heat exchanger. In the process of controlling the rotation speed of the machine and reducing the rotation speed of the compressor, the reduction of the rotation speed of the compressor is prohibited within the predetermined range of the index, or the rotation speed is increased. In the process of decreasing the number, it becomes possible to avoid liquid compression of the compressor due to insufficient heating capability of the low-pressure side refrigerant by the high-pressure side refrigerant in the internal heat exchanger.
[0060]
  According to the fourth aspect of the present invention, the control device that controls the rotation speed of the compressor compresses based on the index indicating the high-pressure side refrigerant temperature of the internal heat exchanger or the low-pressure side refrigerant temperature of the internal heat exchanger. In the process of controlling the rotation speed of the machine and increasing the rotation speed of the compressor, prohibiting the increase in the rotation speed of the compressor within a predetermined range of the index, or reducing the rotation speed and reducing the rotation speed of the compressor In the process of decreasing the compressor, the reduction of the rotational speed of the compressor is prohibited within the predetermined range of the index, or the rotational speed is increased, so in the process of increasing the rotational speed of the compressor, It is possible to avoid the occurrence of liquid compression of the compressor due to insufficient heating capability of the low-pressure side refrigerant by the high-pressure side refrigerant. Moreover, since the inconvenience that the pressure on the high-pressure side abnormally increases can be avoided, the reliability is also improved.
[0061]
  Further, it is possible to avoid liquid compression of the compressor due to insufficient heating ability of the low-pressure side refrigerant by the high-pressure side refrigerant in the internal heat exchanger in the process of decreasing the rotational speed of the compressor.
[0062]
  Also,In each of the above inventions,If the discharge side refrigerant temperature or the suction side refrigerant temperature of the compressor is used as the index, the temperature of the high-pressure side refrigerant entering the internal heat exchanger or the temperature of the low-pressure side refrigerant exiting the internal heat exchanger is accurately determined. it can.
[0063]
  In particular, if the predetermined range of the index obtained from the refrigerant temperature on the discharge side of the compressor is corrected based on the evaporation temperature of the refrigerant in the evaporator, liquid compression can be prevented by more accurate compressor rotation speed control. Will be able to.
[0064]
  Further, when the index is obtained from the suction side refrigerant temperature of the compressor, the predetermined range of the index is corrected based on the refrigerant temperature at the outlet of the gas cooler, and the compressor speed is increased while the compressor speed is rapidly increased. Liquid compression can be prevented.
[0065]
  Each of the above inventions is extremely effective particularly when carbon dioxide whose pressure is increased as in claim 5 is used as a refrigerant.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an internal intermediate pressure type two-stage compression rotary compressor constituting a transcritical refrigerant cycle device according to an embodiment of the present invention.
FIG. 2 is a refrigerant circuit diagram of a car air conditioner according to an embodiment of the transcritical refrigerant cycle device of the present invention.
FIG. 3 is a diagram showing the rotational speed control at the time of starting the rotary compressor by the controller of the transcritical refrigerant cycle device of the present invention.
FIG. 4 is a diagram showing the rotational speed control during steady operation of the rotary compressor by the controller of the transcritical refrigerant cycle device of the present invention.
5 is a diagram illustrating a method of correcting a Hz down prohibition temperature zone in the rotational speed control of FIG. 4;
[Explanation of symbols]
  10 Rotary compressor
  14 Electric elements
  32 First rotary compression element
  34 Second rotational compression element
  102 Controller (control device)
  103, 104, 106 Temperature sensor
  105 Pressure sensor
  154 Gas cooler
  156 Expansion valve (pressure reduction device)
  157 Evaporator
  160 Internal heat exchanger

Claims (5)

圧縮機、ガスクーラ、減圧装置及び蒸発器を順次環状に配管接続して成り、前記ガスクーラから出た高圧側冷媒と前記蒸発器から出た低圧側冷媒とを熱交換させるための内部熱交換器を備え、高圧側が超臨界圧力となる遷臨界冷媒サイクル装置において、
前記圧縮機の回転数を制御する制御装置を備え、該制御装置は、前記内部熱交換器の高圧側冷媒温度、若しくは、当該内部熱交換器の低圧側冷媒温度を示す指標に基づき、前記圧縮機の回転数を制御すると共に、前記圧縮機の回転数を上昇させる過程において、前記指標の所定範囲内で当該圧縮機の回転数上昇を禁止し、若しくは、回転数を低下させることを特徴とする遷臨界冷媒サイクル装置。An internal heat exchanger for exchanging heat between a high-pressure side refrigerant discharged from the gas cooler and a low-pressure side refrigerant discharged from the evaporator; In the transcritical refrigerant cycle system where the high pressure side is supercritical pressure,
A control device for controlling the rotational speed of the compressor, the control device based on an index indicating the high-pressure side refrigerant temperature of the internal heat exchanger or the low-pressure side refrigerant temperature of the internal heat exchanger; In the process of increasing the rotation speed of the compressor while controlling the rotation speed of the compressor, the increase in the rotation speed of the compressor is prohibited within the predetermined range of the index, or the rotation speed is decreased. Transcritical refrigerant cycle device. 前記制御装置は、高圧側冷媒の圧力が上昇した場合、前記圧縮機の回転数上昇を禁止し、若しくは、回転数を低下させ、或いは、当該圧縮機を停止させることを特徴とする請求項１の遷臨界冷媒サイクル装置。2. The control device according to claim 1, wherein when the pressure of the high-pressure side refrigerant increases, the control device prohibits the increase in the rotation speed of the compressor, decreases the rotation speed, or stops the compressor. Transcritical refrigerant cycle equipment. 圧縮機、ガスクーラ、減圧装置及び蒸発器を順次環状に配管接続して成り、前記ガスクーラから出た高圧側冷媒と前記蒸発器から出た低圧側冷媒とを熱交換させるための内部熱交換器を備え、高圧側が超臨界圧力となる遷臨界冷媒サイクル装置において、An internal heat exchanger for exchanging heat between a high-pressure side refrigerant discharged from the gas cooler and a low-pressure side refrigerant discharged from the evaporator; In the transcritical refrigerant cycle system where the high pressure side is supercritical pressure,
前記圧縮機の回転数を制御する制御装置を備え、該制御装置は、前記内部熱交換器の高圧側冷媒温度、若しくは、当該内部熱交換器の低圧側冷媒温度を示す指標に基づき、前記圧縮機の回転数を制御すると共に、前記圧縮機の回転数を低下させる過程において、前記指標の所定範囲内で当該圧縮機の回転数低下を禁止し、若しくは、回転数を上昇させることを特徴とする遷臨界冷媒サイクル装置。  A control device for controlling the rotational speed of the compressor, the control device based on an index indicating the high-pressure side refrigerant temperature of the internal heat exchanger or the low-pressure side refrigerant temperature of the internal heat exchanger; In the process of controlling the rotational speed of the compressor and decreasing the rotational speed of the compressor, the reduction of the rotational speed of the compressor is prohibited within the predetermined range of the index, or the rotational speed is increased. Transcritical refrigerant cycle device. 圧縮機、ガスクーラ、減圧装置及び蒸発器を順次環状に配管接続して成り、前記ガスクーラから出た高圧側冷媒と前記蒸発器から出た低圧側冷媒とを熱交換させるための内部熱交換器を備え、高圧側が超臨界圧力となる遷臨界冷媒サイクル装置において、An internal heat exchanger for exchanging heat between a high-pressure side refrigerant discharged from the gas cooler and a low-pressure side refrigerant discharged from the evaporator; In the transcritical refrigerant cycle system where the high pressure side is supercritical pressure,
前記圧縮機の回転数を制御する制御装置を備え、該制御装置は、前記内部熱交換器の高圧側冷媒温度、若しくは、当該内部熱交換器の低圧側冷媒温度を示す指標に基づき、前記圧縮機の回転数を制御すると共に、前記圧縮機の回転数を上昇させる過程において、前記指標の所定範囲内で当該圧縮機の回転数上昇を禁止し、若しくは、回転数を低下させ、前記圧縮機の回転数を低下させる過程においては、前記指標の所定範囲内で当該圧縮機の回転数低下を禁止し、若しくは、回転数を上昇させることを特徴とする遷臨界冷媒サイクル装置。  A control device for controlling the rotational speed of the compressor, the control device based on an index indicating the high-pressure side refrigerant temperature of the internal heat exchanger or the low-pressure side refrigerant temperature of the internal heat exchanger; In the process of controlling the rotational speed of the compressor and increasing the rotational speed of the compressor, the increase of the rotational speed of the compressor is prohibited within the predetermined range of the index, or the rotational speed is decreased, and the compressor In the process of reducing the rotational speed of the refrigerant, the transcritical refrigerant cycle device is characterized in that the rotational speed of the compressor is prohibited from decreasing or the rotational speed is increased within a predetermined range of the index. 冷媒として二酸化炭素を使用することを特徴とする請求項１、請求項２、請求項３又は請求項４の遷臨界冷媒サイクル装置。  5. The transcritical refrigerant cycle apparatus according to claim 1, wherein carbon dioxide is used as the refrigerant.
JP2003083061A 2003-03-25 2003-03-25 Transcritical refrigerant cycle equipment Expired - Fee Related JP4241127B2 (en)

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