JP2009180406A - Supercritical refrigerating cycle - Google Patents

Supercritical refrigerating cycle Download PDF

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JP2009180406A
JP2009180406A JP2008018569A JP2008018569A JP2009180406A JP 2009180406 A JP2009180406 A JP 2009180406A JP 2008018569 A JP2008018569 A JP 2008018569A JP 2008018569 A JP2008018569 A JP 2008018569A JP 2009180406 A JP2009180406 A JP 2009180406A
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refrigerant
internal heat
refrigeration cycle
temperature
valve
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Hiroyuki Yoshida
宏行 吉田
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Marelli Corp
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Calsonic Kansei Corp
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Priority to JP2008018569A priority Critical patent/JP2009180406A/en
Priority to PCT/JP2009/051409 priority patent/WO2009096442A1/en
Publication of JP2009180406A publication Critical patent/JP2009180406A/en
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    • 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
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/20—Disposition of valves, e.g. of on-off valves or flow control valves
    • F25B41/22—Disposition of valves, e.g. of on-off valves or flow control valves between evaporator and 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
    • F25B43/00—Arrangements for separating or purifying gases or liquids; Arrangements for vaporising the residuum of liquid refrigerant, e.g. by heat
    • F25B43/006—Accumulators
    • 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
    • F25B2400/00—General features or devices for refrigeration machines, plants or systems, combined heating and refrigeration systems or heat-pump systems, i.e. not limited to a particular subgroup of F25B
    • F25B2400/04—Refrigeration circuit bypassing means
    • F25B2400/0419—Refrigeration circuit bypassing means for the superheater

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Power Engineering (AREA)
  • Air-Conditioning For Vehicles (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a supercritical refrigerating cycle capable of combining improvement of cooling capacity by internal heat exchange and prevention of liquefaction of a refrigerant supplied to a compressor by controlling a refrigerant flow rate to an internal heat exchanger on the basis of a refrigerant temperature while reducing the number of components and costs, and improving reliability. <P>SOLUTION: In a CO<SB>2</SB>refrigerating cycle constituted by successively annularly connecting the compressor 1, a gas cooler 2, an expansion valve 3, an evaporator 4 and an accumulator 5, and comprising the internal heat exchanger 6 exchanging heat between a high-pressure refrigerant from the gas cooler 2 and a low-pressure refrigerant from the accumulator 5, a bypass passage 7 bypassing at least a passage at one side of the internal heat exchanger 6, is disposed, and the bypass passage 7 is provided with a first flow rate adjustment valve 8 and a second flow rate adjustment valve 9 sensing the refrigerant temperature to perform valve motion for closing when the high-pressure refrigerant from the gas cooler 2 is cooled by the internal heat exchange, and opening when the low-pressure refrigerant from the accumulator 5 is cooled by the internal heat exchange. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、炭酸ガスを冷媒とし、ガスクーラを出た高圧冷媒とアキュムレータを出た低圧冷媒との間で熱交換する内部熱交換器を備えた超臨界冷凍サイクルに関する。   The present invention relates to a supercritical refrigeration cycle including an internal heat exchanger that uses carbon dioxide as a refrigerant and exchanges heat between a high-pressure refrigerant that has exited a gas cooler and a low-pressure refrigerant that has exited an accumulator.

CO2（二酸化炭素）を冷媒として用いた超臨界冷凍サイクルは、コンプレッサと、ガスクーラと、膨張弁と、エバポレータと、アキュムレータを順次環状に接続する。そして、このサイクルの中で冷房能力を向上するため、ガスクーラ出口冷媒とアキュムレータ出口冷媒を熱交換する内部熱交換器を配置している。 In the supercritical refrigeration cycle using CO 2 (carbon dioxide) as a refrigerant, a compressor, a gas cooler, an expansion valve, an evaporator, and an accumulator are sequentially connected in a ring shape. In order to improve the cooling capacity in this cycle, an internal heat exchanger for exchanging heat between the gas cooler outlet refrigerant and the accumulator outlet refrigerant is arranged.

高温時（高負荷時）は、ガスクーラ出口冷媒が高温（４０〜５０℃程度）で、アキュムレータ出口冷媒は低温（１０℃以下程度）になっており、内部熱交換器は、ガスクーラ出口冷媒の冷却機能を発揮する。   At high temperature (high load), the gas cooler outlet refrigerant is at a high temperature (about 40 to 50 ° C.), the accumulator outlet refrigerant is at a low temperature (about 10 ° C. or less), and the internal heat exchanger cools the gas cooler outlet refrigerant. Demonstrate the function.

この場合、高温時においては内部熱交換器によって、ガスクーラ冷媒出口温度を冷却するよう作用するが、低温時（低負荷時）については、ガスクーラ出口冷媒温度とアキュムレータ出口冷媒温度が逆転し、内部熱交換器によって、コンプレッサへ供給される冷媒を冷却し、液冷媒にして供給するようになるおそれがある。   In this case, the internal heat exchanger acts to cool the gas cooler refrigerant outlet temperature at a high temperature, but at low temperatures (low load), the gas cooler outlet refrigerant temperature and the accumulator outlet refrigerant temperature are reversed, and the internal heat There is a possibility that the refrigerant supplied to the compressor is cooled and supplied as a liquid refrigerant by the exchanger.

このように、低温時に液冷媒の流出によるコンプレッサの液圧縮など、耐久性の悪影響をもたらす構成になっていたため、内部熱交換器による熱交換量を増減させる流量制御弁を設けた超臨界冷凍サイクルが提案されている（例えば、特許文献１，２参照）。
特開２００２−２２８２８２号公報 特開平１１−１９３９６７号公報 Thus, the supercritical refrigeration cycle provided with a flow control valve that increases or decreases the amount of heat exchange by the internal heat exchanger because it was configured to cause adverse effects such as liquid compression of the compressor due to outflow of liquid refrigerant at low temperatures Has been proposed (see, for example, Patent Documents 1 and 2).
JP 2002-228282 A JP 11-193967 A

しかしながら、従来の流量制御弁を設けた超臨界冷凍サイクルにあっては、流量制御するために、温度や圧力をセンサにより感知し、専用のコントローラ等によって流量制御弁の弁開度を制御する電子制御系の構成が必要であるため、部品点数増やコスト増や信頼性低下を招く、という問題があった。   However, in a supercritical refrigeration cycle provided with a conventional flow rate control valve, in order to control the flow rate, an electronic device that senses temperature and pressure with a sensor and controls the valve opening degree of the flow rate control valve with a dedicated controller or the like. Since the configuration of the control system is necessary, there is a problem that the number of parts is increased, the cost is increased, and the reliability is lowered.

本発明は、上記問題に着目してなされたもので、部品点数減やコスト減や信頼性向上を図りながら、冷媒温度によって内部熱交換器への冷媒流量を制御することで、内部熱交換による冷房能力の向上と、コンプレッサへ供給する冷媒の液冷媒化の防止の両立を達成することができる超臨界冷凍サイクルを提供することを目的とする。   The present invention has been made paying attention to the above problems, and by controlling the refrigerant flow rate to the internal heat exchanger according to the refrigerant temperature while reducing the number of parts, reducing the cost and improving the reliability, It is an object of the present invention to provide a supercritical refrigeration cycle capable of achieving both improvement of cooling capacity and prevention of liquid refrigerant supplied to a compressor.

上記目的を達成するため、本発明では、コンプレッサと、ガスクーラと、膨張弁と、エバポレータと、アキュムレータを順次環状に接続し、前記ガスクーラを出た高圧冷媒と前記アキュムレータを出た低圧冷媒との間で熱交換する内部熱交換器を備えた超臨界冷凍サイクルにおいて、
前記内部熱交換器の少なくとも片方の通路をバイパスするバイパス通路を設定し、
前記バイパス通路に、冷媒温度を感知し、内部熱交換により前記ガスクーラを出た高圧冷媒を冷却するとき閉じ、内部熱交換により前記アキュムレータを出た低圧冷媒を冷却するとき開く弁動作を行う流量調整弁を設けたことを特徴とする。 In order to achieve the above object, in the present invention, a compressor, a gas cooler, an expansion valve, an evaporator, and an accumulator are sequentially connected in an annular manner, and between the high-pressure refrigerant that exits the gas cooler and the low-pressure refrigerant that exits the accumulator. In the supercritical refrigeration cycle with an internal heat exchanger that exchanges heat at
Setting a bypass passage for bypassing at least one passage of the internal heat exchanger;
Flow rate adjustment that detects the refrigerant temperature in the bypass passage, closes when the high-pressure refrigerant exiting the gas cooler is cooled by internal heat exchange, and opens when cooling the low-pressure refrigerant exiting the accumulator by internal heat exchange A valve is provided.

よって、本発明の超臨界冷凍サイクルにあっては、内部熱交換器をバイパスするバイパス通路に設けられた流量調整弁が、冷媒温度を感知し、内部熱交換によりガスクーラを出た高圧冷媒を冷却するとき閉じ、内部熱交換によりアキュムレータを出た低圧冷媒を冷却するとき開く弁動作を行う。
したがって、センサやコントローラ等を必要とせずに、バイパス通路を流れる冷媒の流量を調節でき、これによって、電子制御系の構成が必要であるシステムに比べ、部品点数減やコスト減や信頼性向上を図ることができる。
そして、内部熱交換によりガスクーラを出た高圧冷媒を冷却する高負荷時には、内部熱交換器をバイパスするバイパス通路が流量調整弁により閉じられる。よって、内部熱交換器は、ガスクーラ出口冷媒を冷却するように内部熱交換機能を発揮し、これによって、超臨界冷凍サイクルによる冷房能力の向上を図ることができる。
一方、内部熱交換によりアキュムレータを出た低圧冷媒を冷却する低負荷時には、内部熱交換器をバイパスするバイパス通路が流量調整弁により開かれる。よって、内部熱交換器による内部熱交換機能が抑制され、低負荷時にコンプレッサへ供給される冷媒を冷却し、液冷媒にして供給することが防止される。
この結果、部品点数減やコスト減や信頼性向上を図りながら、冷媒温度によって内部熱交換器への冷媒流量を制御することで、内部熱交換による冷房能力の向上と、コンプレッサへ供給する冷媒の液冷媒化の防止の両立を達成することができる。 Therefore, in the supercritical refrigeration cycle of the present invention, the flow rate adjusting valve provided in the bypass passage that bypasses the internal heat exchanger senses the refrigerant temperature and cools the high-pressure refrigerant that has exited the gas cooler by internal heat exchange. The valve is closed when it is closed, and is opened when the low-pressure refrigerant exiting the accumulator is cooled by internal heat exchange.
Therefore, the flow rate of the refrigerant flowing through the bypass passage can be adjusted without the need for a sensor or controller, thereby reducing the number of components, reducing costs, and improving reliability compared to systems that require an electronic control system configuration. Can be planned.
And at the time of the high load which cools the high pressure refrigerant | coolant which came out of the gas cooler by internal heat exchange, the bypass passage which bypasses an internal heat exchanger is closed by a flow regulating valve. Therefore, the internal heat exchanger exhibits an internal heat exchange function so as to cool the gas cooler outlet refrigerant, thereby improving the cooling capacity by the supercritical refrigeration cycle.
On the other hand, at the time of a low load for cooling the low-pressure refrigerant that has exited the accumulator by internal heat exchange, a bypass passage that bypasses the internal heat exchanger is opened by the flow rate adjusting valve. Therefore, the internal heat exchange function by the internal heat exchanger is suppressed, and the refrigerant supplied to the compressor at a low load is prevented from being cooled and supplied as a liquid refrigerant.
As a result, the refrigerant flow rate to the internal heat exchanger is controlled by the refrigerant temperature while reducing the number of parts, reducing costs, and improving reliability, thereby improving the cooling capacity by internal heat exchange and reducing the refrigerant supplied to the compressor. It is possible to achieve both prevention of liquid refrigerant.

以下、本発明の超臨界冷凍サイクルを実現する最良の形態を、図面に示す実施例１に基づいて説明する。   Hereinafter, the best mode for realizing the supercritical refrigeration cycle of the present invention will be described based on Example 1 shown in the drawings.

まず、構成を説明する。
図１は、実施例１のCO2冷凍サイクル（超臨界冷凍サイクル）を示すサイクルシステム図である。 First, the configuration will be described.
FIG. 1 is a cycle system diagram showing a CO 2 refrigeration cycle (supercritical refrigeration cycle) according to the first embodiment.

自然冷媒であるCO2冷媒を用いたCO2冷凍サイクルは、図１に示すように、コンプレッサ１と、ガスクーラ２と、膨張弁３と、エバポレータ４と、アキュムレータ５を順次環状に接続し、前記ガスクーラ２を出た高圧冷媒と前記アキュムレータ５を出た低圧冷媒との間で熱交換する内部熱交換器６を備えることで構成される。 CO 2 refrigeration cycle using CO 2 refrigerant is a natural refrigerant, as shown in FIG. 1, a compressor 1, a gas cooler 2, an expansion valve 3, an evaporator 4 are sequentially connected to the annular accumulator 5, wherein The internal heat exchanger 6 is configured to exchange heat between the high-pressure refrigerant exiting the gas cooler 2 and the low-pressure refrigerant exiting the accumulator 5.

前記コンプレッサ１は、エンジンやモータなどにより駆動され、アキュムレータ５からのガス冷媒を圧縮し、高温・高圧のガス冷媒とする。実施例１では、高圧と低圧の差圧を制御する差圧制御ECV（External Control Valve）を持った外部可変容量制御タイプを採用している。なお、冷媒として用いられるCO2冷媒の飽和ガスは、フッ素冷媒の７倍の密度、1.2倍の蒸発潜熱（単位質量当たり）であるので、単位体積あたりの冷房能力は約８倍になる。このため、コンプレッサ１の吐出容量は、15〜30cc程度で十分性能が発揮できる。 The compressor 1 is driven by an engine, a motor, or the like, and compresses the gas refrigerant from the accumulator 5 to obtain a high-temperature / high-pressure gas refrigerant. In the first embodiment, an external variable displacement control type having a differential pressure control ECV (External Control Valve) for controlling a differential pressure between a high pressure and a low pressure is employed. Note that the saturated gas of the CO 2 refrigerant used as the refrigerant has a density seven times that of the fluorine refrigerant and 1.2 times the latent heat of vaporization (per unit mass), so the cooling capacity per unit volume is about eight times. For this reason, if the discharge capacity of the compressor 1 is about 15 to 30 cc, sufficient performance can be exhibited.

前記ガスクーラ２は、コンプレッサ１からの高温・高圧のガス冷媒を外気と熱交換し、低温・高圧のガス冷媒とする凝縮器である。このガスクーラ２としては、互いに間隔をおいて縦平行に配置された左右一対のヘッダータンクと、両端をそれぞれ前記ヘッダータンクに連通接続して横平行に多数配置された熱交換チューブと、隣接する熱交換チューブの空気流通間隙に配置されたフィンと、を備えて構成される。そして、一対のヘッダータンクの内部が、仕切り手段により横方向に仕切られることにより、熱交換チューブによる冷媒通路が、入口側通路群と中間通路群と出口側通路群というように、少なくとも２つ以上の通路群に区画されている。   The gas cooler 2 is a condenser that exchanges heat between the high-temperature and high-pressure gas refrigerant from the compressor 1 with the outside air to obtain a low-temperature and high-pressure gas refrigerant. The gas cooler 2 includes a pair of left and right header tanks arranged in parallel with each other at intervals, a heat exchange tube arranged in a large number in parallel with both ends connected to the header tank, and adjacent heat tanks. And a fin disposed in the air circulation gap of the exchange tube. Then, the interior of the pair of header tanks is partitioned in the lateral direction by the partitioning means, so that at least two refrigerant passages by the heat exchange tubes are provided, such as an inlet side passage group, an intermediate passage group, and an outlet side passage group. It is divided into passage groups.

前記膨張弁３は、エンジンルーム内に設置され、ガスクーラ２からの高圧ガス冷媒の圧力を低圧の液ガス混合冷媒とする。実施例１の場合、ガスクーラ２の出口冷媒温度及び出口冷媒圧力に基づいて、冷媒の過熱度（スーパーヒート）を一定に保持するように膨張弁開度を制御する制御型膨張弁を採用している。   The expansion valve 3 is installed in the engine room and uses the pressure of the high-pressure gas refrigerant from the gas cooler 2 as a low-pressure liquid-gas mixed refrigerant. In the case of the first embodiment, a control type expansion valve that controls the opening degree of the expansion valve so as to keep the superheat degree of the refrigerant constant based on the outlet refrigerant temperature and the outlet refrigerant pressure of the gas cooler 2 is adopted. Yes.

前記エバポレータ４は、車室内空調を行う車両用空調ユニットA/U内に、送風機等と共に配置される熱交換器である。膨張弁３からの低温・低圧の液ガス混合冷媒を循環させることで周囲の空気から熱を奪い、冷媒の温度を高め、ガス化を促進する。CO2冷媒を用いた冷凍サイクルにおいて、高負荷時における平衡圧は、7MPa（約70bar）以上と高圧になることから、車室内への冷媒漏れは、フッ素冷媒以上の信頼性を確保する必要がある。このため、エバポレータ４は、コア・配管・フランジまでを一体化する構造とし、これにより、Ｏリングシールなどのスローリークを含む車室内への冷媒漏れを防いでいる。 The evaporator 4 is a heat exchanger disposed together with a blower or the like in a vehicle air conditioning unit A / U that performs air conditioning in a vehicle interior. By circulating the low-temperature and low-pressure liquid-gas mixed refrigerant from the expansion valve 3, heat is taken from the surrounding air, the temperature of the refrigerant is increased, and gasification is promoted. In a refrigeration cycle using CO 2 refrigerant, the equilibrium pressure at high load is as high as 7 MPa (about 70 bar) or higher, so it is necessary to ensure the reliability of refrigerant leakage into the passenger compartment is higher than that of fluorine refrigerant. is there. For this reason, the evaporator 4 has a structure in which the core, piping, and flange are integrated, thereby preventing refrigerant leakage into the vehicle compartment including slow leaks such as O-ring seals.

前記アキュムレータ５は、エバポレータ４から導入される液ガス混合冷媒から気液を分離し、ガス冷媒をコンプレッサ１に供給し、CO2冷凍サイクル中の余剰液冷媒を本体内部に貯液する。CO2冷媒を用いた冷凍サイクルでは、高圧圧力が臨界圧を超えた場合、高圧側に液冷媒が溜まらない。このため、フッ素冷媒を用いた冷凍サイクルで一般的なリキッドタンクは採用できず、アキュムレータ５を使って冷媒適正量を管理する。 The accumulator 5 separates the gas and liquid from the liquid-gas mixed refrigerant introduced from the evaporator 4, supplies the gas refrigerant to the compressor 1, and stores the excess liquid refrigerant in the CO 2 refrigeration cycle inside the main body. In the refrigeration cycle using CO 2 refrigerant, liquid refrigerant does not accumulate on the high pressure side when the high pressure exceeds the critical pressure. For this reason, a general liquid tank cannot be adopted in a refrigeration cycle using a fluorine refrigerant, and an appropriate amount of refrigerant is managed using the accumulator 5.

前記内部熱交換器６は、ガスクーラ２を出た高圧冷媒とアキュムレータ５を出た低圧冷媒との間で熱交換するというように、CO2冷凍サイクル内で熱交換し、外部の空気と熱交換しないので、「内部熱交換器」と呼んでいる。この内部熱交換器６により、膨張弁３の入口冷媒温度を外気温度以下まで下げ、エバポレータ４の入口エンタルピを下げることによって、COP（効率:Coefficient Of Performance）を向上させる。 The internal heat exchanger 6 exchanges heat within the CO 2 refrigeration cycle and exchanges heat with external air, such as exchanging heat between the high-pressure refrigerant exiting the gas cooler 2 and the low-pressure refrigerant exiting the accumulator 5. Because it does not, it is called “internal heat exchanger”. The internal heat exchanger 6 lowers the inlet refrigerant temperature of the expansion valve 3 to below the outside air temperature and lowers the inlet enthalpy of the evaporator 4 to improve COP (Coefficient Of Performance).

実施例１では、図１に示すように、前記内部熱交換器６の少なくとも片方の通路をバイパスするバイパス通路７を設定し、前記バイパス通路７に、冷媒温度を感知し、内部熱交換により前記ガスクーラ２を出た高圧冷媒を冷却するとき閉じ、内部熱交換により前記アキュムレータ５を出た低圧冷媒を冷却するとき開く弁動作を行う第１流量調整弁８（流量調整弁）と第２流量調整弁９（流量調整弁）を設けている。   In Example 1, as shown in FIG. 1, a bypass passage 7 that bypasses at least one of the internal heat exchangers 6 is set, the refrigerant temperature is detected in the bypass passage 7, and the heat is exchanged by internal heat exchange. A first flow rate adjustment valve 8 (flow rate adjustment valve) that closes when the high-pressure refrigerant exiting the gas cooler 2 is cooled and opens when cooling the low-pressure refrigerant that exits the accumulator 5 by internal heat exchange, and a second flow rate adjustment. A valve 9 (flow rate adjusting valve) is provided.

前記第１流量調整弁８と前記第２流量調整弁９は、高温側の内部熱交換器６への入口冷媒温度（＝ガスクーラ出口温度）よりも、低温側の内部熱交換器６への入口冷媒温度（＝アキュムレータ出口温度）の方が高い温度条件成立時に弁閉から弁開に切り替え、前記バイパス通路７に冷媒を流す設定とされる。   The first flow rate adjusting valve 8 and the second flow rate adjusting valve 9 have an inlet to the internal heat exchanger 6 on the lower temperature side than the inlet refrigerant temperature (= gas cooler outlet temperature) to the internal heat exchanger 6 on the high temperature side. When the temperature condition is higher when the refrigerant temperature (= accumulator outlet temperature) is higher, the valve is switched from the valve closing state to the valve opening state so that the refrigerant flows through the bypass passage 7.

図２は、実施例１のCO2冷凍サイクル（超臨界冷凍サイクル）の内部熱交換器及びバイパスパイプを示す図で、(a)は内部熱交換器の断面を示し、(b)は内部熱交換器及びバイパスパイプの斜視図を示す。図３は、実施例１のCO2冷凍サイクルに採用された弁閉状態の流量調整弁を示す断面図である。図４は、実施例１のCO2冷凍サイクルに採用された流量調整弁の第１ディスクと第２ディスクを示す斜視図である。図５は、実施例１のCO2冷凍サイクルに採用された弁開状態の流量調整弁を示す断面図である。 FIG. 2 is a diagram showing an internal heat exchanger and a bypass pipe of the CO 2 refrigeration cycle (supercritical refrigeration cycle) of Example 1, wherein (a) shows a cross section of the internal heat exchanger, and (b) shows internal heat. The perspective view of an exchanger and a bypass pipe is shown. FIG. 3 is a cross-sectional view showing the flow regulating valve in the valve closed state employed in the CO 2 refrigeration cycle of the first embodiment. FIG. 4 is a perspective view showing a first disk and a second disk of the flow rate adjusting valve employed in the CO 2 refrigeration cycle of the first embodiment. FIG. 5 is a cross-sectional view showing the valve-opening flow rate adjusting valve employed in the CO 2 refrigeration cycle of the first embodiment.

前記内部熱交換器６は、図２(a)に示すように、中央部に前記ガスクーラ２から前記膨張弁３へと流れる高圧冷媒通路６ａを配置し、この高圧冷媒通路６ａの外周部に、前記アキュムレータ５から前記コンプレッサ１へと流れる複数の低圧冷媒通路６ｂを配置することにより構成される。なお、高圧冷媒通路６ａの冷媒流れ方向と、低圧冷媒通路６ｂの冷媒流れ方向は、逆方向となっている。   As shown in FIG. 2 (a), the internal heat exchanger 6 has a high-pressure refrigerant passage 6a flowing from the gas cooler 2 to the expansion valve 3 at the center, and an outer peripheral portion of the high-pressure refrigerant passage 6a. It is configured by arranging a plurality of low-pressure refrigerant passages 6 b that flow from the accumulator 5 to the compressor 1. The refrigerant flow direction in the high-pressure refrigerant passage 6a and the refrigerant flow direction in the low-pressure refrigerant passage 6b are opposite to each other.

前記バイパス通路７は、図２(b)に示すように、前記アキュムレータ５から前記コンプレッサ１へと流れる低圧冷媒通路６ｂをバイパスするバイパスパイプ１０の内部通路である。ここで、バイパスパイプ１０は、低圧冷媒通路６ｂとバイパス通路７の連通路を有する第１パイプ継ぎ手１１と第２パイプ継ぎ手１２を介して、内部熱交換器６に連結設定される。   The bypass passage 7 is an internal passage of a bypass pipe 10 that bypasses the low-pressure refrigerant passage 6b that flows from the accumulator 5 to the compressor 1, as shown in FIG. 2 (b). Here, the bypass pipe 10 is connected and set to the internal heat exchanger 6 through a first pipe joint 11 and a second pipe joint 12 having a communication path of the low-pressure refrigerant passage 6 b and the bypass passage 7.

前記第１流量調整弁８は、図２(b)に示すように、前記バイパス通路７の入口部に設定され、前記アキュムレータ５からの冷媒温度による変形により通路開度を制御する弁体を有する。前記第２流量調整弁９は、図２(b)に示すように、前記バイパス通路７の出口部に設定され、前記コンプレッサ１への冷媒温度による変形により通路開度を制御する弁体を有する。   As shown in FIG. 2 (b), the first flow rate adjusting valve 8 is set at the inlet of the bypass passage 7 and has a valve body that controls the passage opening degree by deformation due to the refrigerant temperature from the accumulator 5. . As shown in FIG. 2B, the second flow rate adjusting valve 9 is set at the outlet of the bypass passage 7 and has a valve body that controls the passage opening degree by deformation of the compressor 1 due to the refrigerant temperature. .

前記弁体は、図３〜図５に示すように、１箇所に冷媒通路となる通孔１３ａ，１４ａを設定した円形状のディスクを２枚重ね合わせた一対のディスク１３，１４により構成している。   As shown in FIGS. 3 to 5, the valve body is composed of a pair of disks 13, 14 in which two circular disks each having a through hole 13 a, 14 a serving as a coolant passage are set in one place. Yes.

前記一対のディスク１３，１４は、図３に示すように、バイパスパイプ１０に形成したディスク溝に嵌合することで、２つの通孔１３ａ，１４ａが重ならないように位置決めし、ストッパプレート１５により、重ね合わせ面が接触するように取り付けられる。   As shown in FIG. 3, the pair of disks 13 and 14 are positioned so that the two through holes 13 a and 14 a do not overlap with each other by being fitted into a disk groove formed in the bypass pipe 10. And are attached so that the overlapping surfaces are in contact with each other.

前記一対のディスク１３，１４は、線膨張係数の異なる材質の板材を貼り合わせたバイメタル、あるいは、記憶温度を超えると記憶形状に変形する形状記憶合金により構成される。そして、一対のディスク１３，１４に触れる冷媒の温度が高温域では、図３に示すように、少量の冷媒流れを許容しながら、重ね合わせ部分が密着する。また、一対のディスク１３，１４に触れる冷媒の温度が低温域では、図５に示すように、重ね合わせ中央部分が開き、２つの通孔１３ａ，１４ａを介して冷媒が流れるように変形する。ここで、一対のディスク１３，１４の冷媒温度感応の設定は、これ以上温度が低下したらコンプレッサ１へ供給される冷媒を冷却して液冷媒化する温度を境界温度とし、この境界温度より高い温度域を高温域とし、境界温度より低い温度域を低温域とする。   The pair of disks 13 and 14 is made of a bimetal obtained by bonding plate materials made of materials having different linear expansion coefficients, or a shape memory alloy that deforms into a memory shape when the memory temperature is exceeded. And when the temperature of the refrigerant | coolant which touches a pair of discs 13 and 14 is a high temperature range, as shown in FIG. 3, an overlapping part closely_contact | adheres, accept | permitting a small amount of refrigerant | coolants flow. Further, when the temperature of the refrigerant that touches the pair of disks 13 and 14 is in a low temperature range, as shown in FIG. 5, the overlapping central portion is opened and the refrigerant flows so as to flow through the two through holes 13 a and 14 a. Here, the refrigerant temperature sensitivity of the pair of disks 13 and 14 is set such that the temperature at which the refrigerant supplied to the compressor 1 is cooled to become a liquid refrigerant when the temperature is further lowered is set as a boundary temperature, and the temperature is higher than the boundary temperature. The temperature range is the high temperature range, and the temperature range lower than the boundary temperature is the low temperature range.

次に、作用を説明する。
まず、「超臨界冷凍サイクルの技術」の説明を行い、続いて、実施例１の超臨界冷凍サイクルにおける作用を、「流量調整弁によるバイパス冷媒流量調整作用」、「バイパス冷媒流量の制限による内部熱交換作用」、「バイパス冷媒流量の確保による内部熱交換制限作用」に分けて説明する。 Next, the operation will be described.
First, the “supercritical refrigeration cycle technology” will be described, and then the operation in the supercritical refrigeration cycle of Example 1 will be described as “bypass refrigerant flow rate adjusting operation by the flow rate adjusting valve” and “bypass refrigerant flow rate restriction internal”. The description will be divided into “heat exchange action” and “internal heat exchange restriction action by ensuring the bypass refrigerant flow rate”.

［超臨界冷凍サイクルの技術］
高まる地球温暖化防止の世界動向に対応するべく、自然冷媒であるCO2冷媒を用いたCO2冷凍サイクルによるエアコンシステムの開発が急ピッチで進められている。このCO2冷凍サイクルは、CO2冷媒の特性として、臨界温度が31.1℃と低く、外気温度が約30℃以上の負荷では、高圧圧力が臨界圧（臨界圧7.4MPa以上でかつ温度31.1℃以上のエリアを超臨界領域という。）を超えてしまう。このため、CO2冷凍サイクルは超臨界冷凍サイクルと呼ばれ、現行は、図６に示すように、コンプレッサと、ガスクーラと、膨張弁と、エバポレータと、アキュムレータを順次環状に接続し、ガスクーラ出口冷媒とアキュムレータ出口冷媒の間で熱交換するように、図７に示すような内部熱交換器を配置している。この内部熱交換器は、ガスクーラ出口冷媒を冷却することで冷房能力向上すると共に、アキュムレータ出口冷媒を加熱することでスーパーヒートを確保している。 [Supercritical refrigeration cycle technology]
In order to respond to the growing global trend to prevent global warming, the development of air conditioning systems using CO 2 refrigeration cycles using CO 2 refrigerant, which is a natural refrigerant, is proceeding at a rapid pace. In this CO 2 refrigeration cycle, as a characteristic of CO 2 refrigerant, the critical temperature is as low as 31.1 ° C, and the high pressure is critical pressure (critical pressure is 7.4MPa or more and temperature is 31.1 ° C or more at the outside air temperature of about 30 ° C or more. This area is called the supercritical region.) For this reason, the CO 2 refrigeration cycle is called a supercritical refrigeration cycle. Currently, as shown in FIG. 6, a compressor, a gas cooler, an expansion valve, an evaporator, and an accumulator are sequentially connected in an annular manner, and the refrigerant at the gas cooler outlet An internal heat exchanger as shown in FIG. 7 is arranged to exchange heat between the refrigerant and the accumulator outlet refrigerant. This internal heat exchanger improves the cooling capacity by cooling the gas cooler outlet refrigerant and secures superheat by heating the accumulator outlet refrigerant.

高温時（高負荷時）は、ガスクーラ出口冷媒が高温（４０〜５０℃程度）で、アキュムレータ出口冷媒は低温（１０℃以下程度）になっており、内部熱交換器は、ガスクーラ出口冷媒の冷却機能を発揮する。しかし、低温時（低負荷時）については、ガスクーラ出口冷媒温度とアキュムレータ出口冷媒温度が逆転し、内部熱交換器によって、コンプレッサへ供給される冷媒を冷却し、液冷媒にして供給するようになるおそれがある。   At high temperature (high load), the gas cooler outlet refrigerant is high temperature (about 40-50 ° C.), the accumulator outlet refrigerant is low temperature (about 10 ° C. or less), and the internal heat exchanger cools the gas cooler outlet refrigerant. Demonstrate the function. However, when the temperature is low (when the load is low), the gas cooler outlet refrigerant temperature and the accumulator outlet refrigerant temperature are reversed, and the internal heat exchanger cools the refrigerant supplied to the compressor and supplies it as liquid refrigerant. There is a fear.

このように、低温時に液冷媒の流出によるコンプレッサの液圧縮など、耐久性の悪影響をもたらす構成になっていたため、特開２００２−２２８２８２号公報や特開平１１−１９３９６７号公報等にて、内部熱交換器による熱交換量を増減させる流量制御弁を設けた超臨界冷凍サイクルが提案されている。   As described above, since it has a configuration that adversely affects durability such as liquid compression of the compressor due to outflow of liquid refrigerant at low temperatures, internal heat is disclosed in Japanese Patent Laid-Open Nos. 2002-228282 and 11-193967. There has been proposed a supercritical refrigeration cycle provided with a flow control valve for increasing or decreasing the amount of heat exchange by the exchanger.

しかしながら、従来公報に記載される流量制御弁を設けた超臨界冷凍サイクルにあっては、流量制御するために、温度や圧力をセンサにより感知し、専用のコントローラ等によって流量制御弁の弁開度を制御する電子制御系の構成が必要であるため、部品点数増やコスト増や信頼性低下を招く。特に、信頼性に関しては、超臨界冷凍サイクルが高圧システムであり、かつ、過酷な環境にある車両に搭載される点から重要である。   However, in the supercritical refrigeration cycle provided with the flow control valve described in the conventional publication, the temperature and pressure are sensed by a sensor in order to control the flow, and the valve opening degree of the flow control valve by a dedicated controller or the like Therefore, the configuration of an electronic control system that controls the above-described process is required, resulting in an increase in the number of parts, an increase in cost, and a decrease in reliability. In particular, reliability is important because the supercritical refrigeration cycle is a high-pressure system and is mounted on a vehicle in a harsh environment.

本発明者は、ガスクーラ出口冷媒温度とアキュムレータ出口冷媒温度の逆転を、内部熱交換される冷媒温度を監視により検知することが可能である点に着目した。この着目点にしたがって、内部熱交換器をバイパスする通路を設け、このバイパス通路に冷媒温度に感応して弁動作する流量調整弁を設ける構成を採用した。この構成を採用することにより、部品点数減やコスト減や信頼性向上を図りながら、冷媒温度によって内部熱交換器への冷媒流量を制御することで、内部熱交換による冷房能力の向上と、コンプレッサへ供給する冷媒の液冷媒化の防止の両立を達成することができるようにした。   The inventor of the present invention has focused on the fact that the reversal of the gas cooler outlet refrigerant temperature and the accumulator outlet refrigerant temperature can be detected by monitoring the refrigerant temperature for internal heat exchange. In accordance with this point of interest, a configuration is adopted in which a passage that bypasses the internal heat exchanger is provided, and a flow rate adjusting valve that operates in response to the refrigerant temperature is provided in the bypass passage. By adopting this configuration, the refrigerant flow rate to the internal heat exchanger is controlled by the refrigerant temperature while reducing the number of parts, reducing costs, and improving reliability. It was made possible to achieve both prevention of liquid refrigerant supply to the refrigerant.

［流量調整弁によるバイパス冷媒流量調整作用］
実施例１のCO2冷凍サイクルにあっては、内部熱交換器６をバイパスするバイパス通路７に設けられた第１流量調整弁８と第２流量調整弁９が、冷媒温度を感知し、内部熱交換によりガスクーラ２を出た高圧冷媒を冷却するとき閉じ、内部熱交換によりアキュムレータ５を出た低圧冷媒を冷却するとき開く弁動作を行う。 [Bypass refrigerant flow rate adjustment by flow rate adjustment valve]
In the CO 2 refrigeration cycle of the first embodiment, the first flow rate adjusting valve 8 and the second flow rate adjusting valve 9 provided in the bypass passage 7 bypassing the internal heat exchanger 6 sense the refrigerant temperature, and The valve operation is closed when the high-pressure refrigerant exiting the gas cooler 2 is cooled by heat exchange and opened when the low-pressure refrigerant exiting the accumulator 5 is cooled by internal heat exchange.

第１流量調整弁８と第２流量調整弁９が閉じている遮断時、図３に示すように、第１ディスク１３と第２ディスク１４は、冷媒温度により通常の平板と同様に、直線状になっており、２つの通孔１３ａ，１４ａが互いに塞ぐ形となり、バイパス通路７に冷媒は流れない。しかし、厳密に言うと、平板状の第１ディスク１３と第２ディスク１４の接触により、完全にシールすることはできず、図３の点線矢印で示すように、少量の冷媒が流れることになる。このように、少量の冷媒が流れることにより、弁体である第１ディスク１３と第２ディスク１４は、実際の冷媒に触れることができ、正確な温度制御が可能となる。   When the first flow rate adjusting valve 8 and the second flow rate adjusting valve 9 are closed, as shown in FIG. 3, the first disk 13 and the second disk 14 are linear, like a normal flat plate, depending on the refrigerant temperature. The two through holes 13a and 14a are closed to each other, and the refrigerant does not flow into the bypass passage 7. However, strictly speaking, due to the contact between the flat first disk 13 and the second disk 14, it cannot be completely sealed, and a small amount of refrigerant flows as shown by the dotted arrow in FIG. 3. . Thus, when a small amount of refrigerant flows, the first disk 13 and the second disk 14 that are valve bodies can come into contact with the actual refrigerant, and accurate temperature control becomes possible.

一方、第１流量調整弁８と第２流量調整弁９が開いている開放時、図５に示すように、向かい合った第１ディスク１３と第２ディスク１４は、冷媒温度により平板形状から、互いに異なる方向の湾曲ドーム形状に変化する。このため、２つの通孔１３ａ，１４ａの間に通路隙間Ｓが形成され、通孔１３ａ→通路隙間Ｓ→通孔１４ａを経過してバイパス通路７に冷媒が流れる。   On the other hand, when the first flow rate adjusting valve 8 and the second flow rate adjusting valve 9 are opened and opened, as shown in FIG. 5, the first disk 13 and the second disk 14 facing each other have a plate shape depending on the refrigerant temperature. It changes into a curved dome shape in different directions. Therefore, a passage gap S is formed between the two through holes 13a and 14a, and the refrigerant flows into the bypass passage 7 after passing through the through hole 13a → the passage gap S → the through hole 14a.

したがって、センサやコントローラ等を必要とせずに、バイパス通路７を流れる冷媒の流量を調節でき、これによって、電子制御系の構成が必要であるシステムに比べ、部品点数減やコスト減や信頼性向上を図ることができる。   Therefore, the flow rate of the refrigerant flowing through the bypass passage 7 can be adjusted without requiring a sensor, a controller, etc., thereby reducing the number of parts, reducing the cost, and improving the reliability compared to a system that requires an electronic control system configuration. Can be achieved.

［バイパス冷媒流量の制限による内部熱交換作用］
内部熱交換によりガスクーラ２を出た高圧冷媒を冷却する高負荷時には、内部熱交換器６をバイパスするバイパス通路７が、第１流量調整弁８と第２流量調整弁９により閉じられる。つまり、バイパス通路７を流れる冷媒流量が制限され、アキュムレータ５を出た低圧冷媒の大半は、内部熱交換器６の複数の低圧冷媒通路６ｂを経過することで内部熱交換を行った後、コンプレッサ１へと供給される。 [Internal heat exchange effect by limiting the flow rate of bypass refrigerant]
When the high-pressure refrigerant that has exited the gas cooler 2 is cooled by internal heat exchange, the bypass passage 7 that bypasses the internal heat exchanger 6 is closed by the first flow rate adjustment valve 8 and the second flow rate adjustment valve 9. That is, the flow rate of the refrigerant flowing through the bypass passage 7 is limited, and most of the low-pressure refrigerant exiting the accumulator 5 undergoes internal heat exchange by passing through the plurality of low-pressure refrigerant passages 6b of the internal heat exchanger 6, and then the compressor 1 is supplied.

よって、内部熱交換器６は、ガスクーラ出口冷媒とアキュムレータ出口冷媒との間で熱交換するという内部熱交換作用を示す。この内部熱交換作用のうち、ガスクーラ出口冷媒を冷却する機能によって、膨張弁３の入口冷媒温度を低下させ、エバポレータ４の入口エンタルピを下げることによって、COPを向上させる。言い換えると、CO2冷凍サイクルによる冷房能力の向上を図ることができる。また、内部熱交換作用のうち、アキュムレータ出口冷媒を加熱する機能によって、スーパーヒートを確保したガス冷媒をコンプレッサ１へ供給することができる。 Therefore, the internal heat exchanger 6 exhibits an internal heat exchange action of exchanging heat between the gas cooler outlet refrigerant and the accumulator outlet refrigerant. Of this internal heat exchange action, the function of cooling the gas cooler outlet refrigerant reduces the inlet refrigerant temperature of the expansion valve 3 and lowers the inlet enthalpy of the evaporator 4 to improve the COP. In other words, the cooling capacity can be improved by the CO 2 refrigeration cycle. Moreover, the gas refrigerant which ensured superheat can be supplied to the compressor 1 by the function of heating the accumulator outlet refrigerant in the internal heat exchange action.

［バイパス冷媒流量の確保による内部熱交換制限作用］
一方、内部熱交換によりアキュムレータ５を出た低圧冷媒を冷却する低負荷時には、内部熱交換器６をバイパスするバイパス通路７が第１流量調整弁８と第２流量調整弁９により開かれる。つまり、アキュムレータ５を出た低圧冷媒の大半はバイパス通路７を流れることになり、内部熱交換器６による内部熱交換を行わないで、低圧冷媒はアキュムレータ５からそのままコンプレッサ１へと供給される。 [Internal heat exchange restriction by securing bypass refrigerant flow rate]
On the other hand, at the time of low load in which the low-pressure refrigerant that has exited the accumulator 5 is cooled by internal heat exchange, a bypass passage 7 that bypasses the internal heat exchanger 6 is opened by the first flow rate adjustment valve 8 and the second flow rate adjustment valve 9. That is, most of the low-pressure refrigerant that has exited the accumulator 5 flows through the bypass passage 7, and the low-pressure refrigerant is supplied from the accumulator 5 to the compressor 1 as it is without performing internal heat exchange by the internal heat exchanger 6.

よって、内部熱交換器６による内部熱交換機能が抑制され、低負荷時にコンプレッサ１へ供給される冷媒を冷却し、液冷媒にして供給することが防止される。この結果、コンプレッサ１へ液冷媒が流入し、液圧縮を余儀なくされることによる、コンプレッサ１の耐久性低下やコンプレッサ１の動力増加を抑えることが可能となる。   Therefore, the internal heat exchange function by the internal heat exchanger 6 is suppressed, and the refrigerant supplied to the compressor 1 at the time of low load is prevented from being cooled and supplied as a liquid refrigerant. As a result, it is possible to suppress a decrease in durability of the compressor 1 and an increase in power of the compressor 1 due to liquid refrigerant flowing into the compressor 1 and forced liquid compression.

次に、効果を説明する。
実施例１のCO2冷凍サイクルにあっては、下記に列挙する効果を得ることができる。 Next, the effect will be described.
In the CO 2 refrigeration cycle of Example 1, the effects listed below can be obtained.

(1) コンプレッサ１と、ガスクーラ２と、膨張弁３と、エバポレータ４と、アキュムレータ５を順次環状に接続し、前記ガスクーラ２を出た高圧冷媒と前記アキュムレータ５を出た低圧冷媒との間で熱交換する内部熱交換器６を備えたCO2冷凍サイクルにおいて、前記内部熱交換器６の少なくとも片方の通路をバイパスするバイパス通路７を設定し、前記バイパス通路７に、冷媒温度を感知し、内部熱交換により前記ガスクーラ２を出た高圧冷媒を冷却するとき閉じ、内部熱交換により前記アキュムレータ５を出た低圧冷媒を冷却するとき開く弁動作を行う流量調整弁（第１流量調整弁８，第２流量調整弁９）を設けたため、部品点数減やコスト減や信頼性向上を図りながら、冷媒温度によって内部熱交換器６への冷媒流量を制御することで、内部熱交換による冷房能力の向上と、コンプレッサ１へ供給する冷媒の液冷媒化の防止の両立を達成することができる。 (1) The compressor 1, the gas cooler 2, the expansion valve 3, the evaporator 4, and the accumulator 5 are sequentially connected in an annular manner, and between the high-pressure refrigerant that has exited the gas cooler 2 and the low-pressure refrigerant that has exited the accumulator 5. In a CO 2 refrigeration cycle having an internal heat exchanger 6 for heat exchange, a bypass passage 7 for bypassing at least one of the internal heat exchanger 6 is set, and a refrigerant temperature is detected in the bypass passage 7. A flow rate adjusting valve (first flow rate adjusting valve 8, which is closed when cooling the high pressure refrigerant exiting the gas cooler 2 by internal heat exchange and opens when cooling the low pressure refrigerant exiting the accumulator 5 by internal heat exchange. Since the second flow rate adjusting valve 9) is provided, the refrigerant flow rate to the internal heat exchanger 6 is controlled by the refrigerant temperature while reducing the number of parts, reducing the cost and improving the reliability. The improvement of the cooling capacity by parts heat exchanger, it is possible to achieve both the prevention of the liquid refrigerant of the refrigerant supplied to the compressor 1.

(2) 前記流量調整弁は、高温側の内部熱交換器６への入口冷媒温度よりも、低温側の内部熱交換器６への入口冷媒温度の方が高い温度条件成立時に弁閉から弁開に切り替え、前記バイパス通路７に冷媒を流す設定としたため、冷媒温度条件のみにより内部熱交換の態様が、ガスクーラ２を出た高圧冷媒を冷却する態様か、アキュムレータ５を出た低圧冷媒を冷却する態様かを把握し、冷媒温度を感知する流量調整弁によりバイパス通路７を流す冷媒流量を調整することができる。   (2) The flow rate adjusting valve is closed when the temperature condition is established when the refrigerant temperature at the inlet to the low-temperature internal heat exchanger 6 is higher than the refrigerant temperature at the inlet to the high-temperature internal heat exchanger 6. Since the refrigerant is set to flow through the bypass passage 7 in the open state, the internal heat exchange mode is the mode in which the high-pressure refrigerant that has exited the gas cooler 2 is cooled only by the refrigerant temperature condition, or the low-pressure refrigerant that has exited the accumulator 5 is cooled. The flow rate of the refrigerant flowing through the bypass passage 7 can be adjusted by a flow rate adjustment valve that senses the refrigerant temperature and senses the refrigerant temperature.

(3) 前記バイパス通路７は、前記アキュムレータ５から前記コンプレッサ１へと流れる低圧冷媒通路をバイパスする通路であり、前記流量調整弁は、前記バイパス通路７の入口部に設定され、前記アキュムレータ５からの冷媒温度による変形により通路開度を制御する弁体を有する第１流量調整弁８と、前記バイパス通路７の出口部に設定され、前記コンプレッサ１への冷媒温度による変形により通路開度を制御する弁体を有する第２流量調整弁９により構成したため、バイパス通路７の出入口部での冷媒温度をそれぞれ感知して弁動作する２つの流量調整弁８，９により、応答性良く、かつ、確実にバイパス通路７を流す冷媒流量を調整することができる。つまり、アキュムレータ５からの冷媒温度の変化と、コンプレッサ１への冷媒温度の変化のタイミングにズレがあった場合、先に温度変化に感応した流量調整弁が弁動作する。また、２つの流量調整弁８，９のうち、一方の流量調整弁の温度感知弁動作に不具合を生じても、他方の流量調整弁の温度感知弁動作によりこれを補うことができる。   (3) The bypass passage 7 is a passage that bypasses the low-pressure refrigerant passage that flows from the accumulator 5 to the compressor 1, and the flow rate adjustment valve is set at the inlet of the bypass passage 7, and the accumulator 5 The first flow rate adjusting valve 8 having a valve body that controls the passage opening degree by deformation due to the refrigerant temperature and the outlet portion of the bypass passage 7, and the passage opening degree is controlled by deformation due to the refrigerant temperature to the compressor 1. Since the second flow rate adjusting valve 9 has a valve body that performs the above operation, the two flow rate adjusting valves 8 and 9 that respectively detect the refrigerant temperature at the inlet / outlet portion of the bypass passage 7 and perform valve operation have good responsiveness and reliability. The flow rate of the refrigerant flowing through the bypass passage 7 can be adjusted. That is, when there is a difference between the change in the refrigerant temperature from the accumulator 5 and the change in the refrigerant temperature to the compressor 1, the flow rate adjustment valve that is sensitive to the temperature change first operates. In addition, even if a malfunction occurs in the temperature sensing valve operation of one of the two flow rate regulating valves 8, 9, this can be compensated by the temperature sensing valve operation of the other flow rate regulating valve.

(4) 前記弁体は、少なくとも１箇所に冷媒通路となる通孔１３ａ，１４ａを設定したディスクを２枚重ね合わせた一対のディスク１３，１４により構成し、前記一対のディスク１３，１４は、２つの通孔１３ａ，１４ａが重ならないように位置決めし、冷媒温度が高温域では重ね合わせ部分が密着し、冷媒温度が低温域で重ね合わせ中央部分が開くように変形するため、弁体そのものが冷媒温度感知部材となり、弁駆動部材や弁動作軸等を冷媒温度感知部材とする場合に比べ、部品点数が少ない構成で、弁動作安定性の高い流量調整弁とすることができる。   (4) The valve body is constituted by a pair of disks 13 and 14 in which two disks having through holes 13a and 14a serving as refrigerant passages are set in at least one place, and the pair of disks 13 and 14 includes: Since the two through holes 13a and 14a are positioned so as not to overlap each other, and the overlapping part is in close contact when the refrigerant temperature is high, and the overlapping part is opened when the refrigerant temperature is low, the valve body itself is Compared to the case where the refrigerant temperature sensing member is used, and the valve driving member, the valve operating shaft and the like are refrigerant temperature sensing members, the flow rate adjusting valve can be configured with a high number of parts and with high valve operation stability.

(5) 前記一対のディスク１３，１４は、線膨張係数の異なる材質の板材を貼り合わせたバイメタルにより構成したため、冷媒の温度変化に応じた変形量により、冷媒の温度変化に追従して徐々にバイパス通路７を流す冷媒流量を調整することができる。   (5) Since the pair of disks 13 and 14 are made of a bimetal obtained by bonding plate materials made of materials having different linear expansion coefficients, the pair of disks 13 and 14 gradually follow the temperature change of the refrigerant according to the deformation amount according to the temperature change of the refrigerant. The flow rate of the refrigerant flowing through the bypass passage 7 can be adjusted.

(6) 前記一対のディスク１３，１４は、記憶温度を超えると記憶形状に変形する形状記憶合金により構成したため、冷媒温度が記憶温度の前後に変化する場合、記憶温度を境にしてバイパス通路７を流す冷媒流量を切り替え調整することができる。   (6) Since the pair of disks 13 and 14 are made of a shape memory alloy that deforms into a memorized shape when the memorized temperature is exceeded, when the refrigerant temperature changes before and after the memorized temperature, the bypass passage 7 It is possible to switch and adjust the flow rate of the refrigerant flowing.

以上、本発明の超臨界冷凍サイクルを実施例１に基づき説明してきたが、具体的な構成については、この実施例１に限られるものではなく、特許請求の範囲の各請求項に係る発明の要旨を逸脱しない限り、設計の変更や追加等は許容される。   As described above, the supercritical refrigeration cycle of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and the invention according to each claim of the claims is described. Design changes and additions are allowed without departing from the gist.

実施例１では、アキュムレータからコンプレッサへと流れる低圧冷媒通路をバイパスするバイパス通路の例を示した。しかし、ガスクーラから膨張弁へと流れる高圧冷媒通路をバイパスするバイパス通路としても良いし、さらに、低圧冷媒通路と高圧冷媒通路をバイパスする２つのバイパス通路の例としても良い。   In the first embodiment, an example of the bypass passage that bypasses the low-pressure refrigerant passage that flows from the accumulator to the compressor is shown. However, it may be a bypass passage that bypasses the high-pressure refrigerant passage that flows from the gas cooler to the expansion valve, or may be an example of two bypass passages that bypass the low-pressure refrigerant passage and the high-pressure refrigerant passage.

実施例１では、流量調整弁として、バイパス通路の出入口部に設定され第１流量調整弁と第２流量調整弁により構成した例を示した。しかし、バイパス通路の途中位置に１つの流量調整弁を設定した例であっても良い。   In the first embodiment, the example in which the flow rate adjusting valve is configured by the first flow rate adjusting valve and the second flow rate adjusting valve that are set at the entrance / exit portion of the bypass passage is shown. However, an example in which one flow rate adjustment valve is set in the middle of the bypass passage may be used.

実施例１では、冷媒温度を感知して弁動作する流量調整弁として、冷媒温度による変形により通路開度を制御する弁体を有する例を示した。しかし、冷媒温度による変形により通路開度を制御する弁駆動部材を有する例としても良いし、冷媒温度による変形により通路開度を制御する弁動作軸を有する例としても良い。   In Example 1, the example which has a valve body which controls a passage opening degree by the deformation | transformation by a refrigerant temperature was shown as a flow regulating valve which detects a refrigerant temperature and valve-operates. However, it may be an example having a valve drive member that controls the passage opening by deformation due to the refrigerant temperature, or an example having a valve operating shaft that controls the passage opening by deformation due to the refrigerant temperature.

実施例１では、流量調整弁の弁体として、１箇所に冷媒通路となる通孔を設定したディスクを２枚重ね合わせた一対のディスクにより構成した例を示した。しかし、通孔を複数設定したディスクを２枚重ね合わせた一対のディスクにより構成しても良い。また、通孔の代わり、あるいは、通孔と共に冷媒通路となる切り欠き溝を設定したディスクを２枚重ね合わせた一対のディスクにより構成しても良い。   In the first embodiment, an example is shown in which the disc of the flow rate adjusting valve is configured by a pair of discs in which two discs each having a through hole serving as a refrigerant passage are overlapped. However, a pair of discs in which two discs having a plurality of through holes are overlapped may be used. Further, instead of the through holes, or a pair of discs in which two discs in which notched grooves serving as refrigerant passages are set together with the through holes are overlapped.

実施例１では、一対のディスクを、バイメタルあるいは形状記憶合金により構成した例を示した。しかし、一対のディスクの一部を、バイメタルあるいは形状記憶合金により構成した例であっても良いし、バイメタルや形状記憶合金以外の温度感応素材を用いて一対のディスクを構成しても良い。   In the first embodiment, an example in which a pair of disks is made of a bimetal or a shape memory alloy is shown. However, an example in which a part of the pair of disks is made of a bimetal or a shape memory alloy may be used, or the pair of disks may be made of a temperature sensitive material other than the bimetal or the shape memory alloy.

要するに、内部熱交換器の少なくとも片方の通路をバイパスするバイパス通路を設定し、バイパス通路に、冷媒温度を感知し、内部熱交換によりガスクーラを出た高圧冷媒を冷却するとき閉じ、内部熱交換によりアキュムレータを出た低圧冷媒を冷却するとき開く弁動作を行う流量調整弁を設けたものであれば、実施例１に限られることはない。   In short, a bypass passage that bypasses at least one of the passages of the internal heat exchanger is set, the refrigerant temperature is detected in the bypass passage, closed when cooling the high-pressure refrigerant that has exited the gas cooler by internal heat exchange, and by internal heat exchange. The present invention is not limited to the first embodiment as long as a flow rate adjusting valve that performs a valve operation that opens when the low-pressure refrigerant that has exited the accumulator is cooled is provided.

実施例１では、車両のエアコンシステムに適用するCO2冷凍サイクルの例を示したが、車両以外、例えば、家庭用のエアコンシステムや工場や事業所のエアコンシステム等の超臨界冷凍サイクルとしても適用できる。要するに、コンプレッサと、ガスクーラと、膨張弁と、エバポレータと、アキュムレータを順次環状に接続し、ガスクーラを出た高圧冷媒とアキュムレータを出た低圧冷媒との間で熱交換する内部熱交換器を備えた超臨界冷凍サイクルであれば適用できる。 In the first embodiment, an example of a CO 2 refrigeration cycle applied to an air conditioner system of a vehicle has been shown. However, it is also applied to a supercritical refrigeration cycle such as a home air conditioner system or a factory or office air conditioner system other than the vehicle. it can. In short, a compressor, a gas cooler, an expansion valve, an evaporator, and an accumulator are sequentially connected in an annular manner, and an internal heat exchanger for exchanging heat between the high-pressure refrigerant exiting the gas cooler and the low-pressure refrigerant exiting the accumulator is provided. Any supercritical refrigeration cycle can be applied.

実施例１のCO2冷凍サイクル（超臨界冷凍サイクル）を示すサイクルシステム図である。1 is a cycle system diagram showing a CO 2 refrigeration cycle (supercritical refrigeration cycle) of Example 1. FIG. 実施例１のCO2冷凍サイクル（超臨界冷凍サイクル）の内部熱交換器及びバイパスパイプを示す図で、(a)は内部熱交換器の断面を示し、(b)は内部熱交換器及びバイパスパイプの斜視図を示す。A diagram showing an internal heat exchanger and the bypass pipe CO 2 refrigeration cycle of Example 1 (supercritical refrigerating cycle), (a) shows a cross section of the internal heat exchanger, (b) internal heat exchanger and bypass The perspective view of a pipe is shown. 実施例１のCO2冷凍サイクルに採用された弁閉状態の流量調整弁を示す断面図である。FIG. 3 is a cross-sectional view showing a flow rate regulating valve in a valve closed state employed in the CO 2 refrigeration cycle of Example 1. 実施例１のCO2冷凍サイクルに採用された流量調整弁の第１ディスクと第２ディスクを示す斜視図である。It is a perspective view showing the first and second disks of the flow regulating valve employed in the CO 2 refrigeration cycle of Example 1. 実施例１のCO2冷凍サイクルに採用された弁開状態の流量調整弁を示す断面図である。FIG. 3 is a cross-sectional view showing a flow rate adjustment valve in an open state employed in the CO 2 refrigeration cycle of Example 1; 現行のCO2冷凍サイクルを示すサイクルシステム図である。It is a cycle system diagram showing the current CO 2 refrigeration cycle. 現行のCO2冷凍サイクルの内部熱交換器を示す斜視図である。Is a perspective view showing an internal heat exchanger of the current CO 2 refrigeration cycle.

符号の説明Explanation of symbols

１ コンプレッサ
２ ガスクーラ
３ 膨張弁
４ エバポレータ
５ アキュムレータ
６ 内部熱交換器
６ａ 高圧冷媒通路
６ｂ 低圧冷媒通路
７ バイパス通路
８ 第１流量調整弁（流量調整弁）
９ 第２流量調整弁（流量調整弁）
１０ バイパスパイプ
１１ 第１パイプ継ぎ手
１２ 第２パイプ継ぎ手
１３，１４ 一対のディスク
１３ａ，１４ａ 通孔 DESCRIPTION OF SYMBOLS 1 Compressor 2 Gas cooler 3 Expansion valve 4 Evaporator 5 Accumulator 6 Internal heat exchanger 6a High pressure refrigerant path 6b Low pressure refrigerant path 7 Bypass path 8 First flow rate adjustment valve (flow rate adjustment valve)
9 Second flow rate adjustment valve (flow rate adjustment valve)
DESCRIPTION OF SYMBOLS 10 Bypass pipe 11 1st pipe joint 12 2nd pipe joint 13, 14 A pair of disk 13a, 14a Through-hole

Claims (6)

コンプレッサと、ガスクーラと、膨張弁と、エバポレータと、アキュムレータを順次環状に接続し、前記ガスクーラを出た高圧冷媒と前記アキュムレータを出た低圧冷媒との間で熱交換する内部熱交換器を備えた超臨界冷凍サイクルにおいて、
前記内部熱交換器の少なくとも片方の通路をバイパスするバイパス通路を設定し、
前記バイパス通路に、冷媒温度を感知し、内部熱交換により前記ガスクーラを出た高圧冷媒を冷却するとき閉じ、内部熱交換により前記アキュムレータを出た低圧冷媒を冷却するとき開く弁動作を行う流量調整弁を設けたことを特徴とする超臨界冷凍サイクル。 A compressor, a gas cooler, an expansion valve, an evaporator, and an accumulator are sequentially connected in an annular manner, and an internal heat exchanger for exchanging heat between the high-pressure refrigerant exiting the gas cooler and the low-pressure refrigerant exiting the accumulator is provided. In the supercritical refrigeration cycle,
Setting a bypass passage for bypassing at least one passage of the internal heat exchanger;
Flow rate adjustment that detects the refrigerant temperature in the bypass passage, closes when the high-pressure refrigerant exiting the gas cooler is cooled by internal heat exchange, and opens when cooling the low-pressure refrigerant exiting the accumulator by internal heat exchange A supercritical refrigeration cycle characterized by providing a valve. 請求項１に記載された超臨界冷凍サイクルにおいて、
前記流量調整弁は、高温側の内部熱交換器への入口冷媒温度よりも、低温側の内部熱交換器への入口冷媒温度の方が高い温度条件成立時に弁閉から弁開に切り替え、前記バイパス通路に冷媒を流す設定としたことを特徴とする超臨界冷凍サイクル。 In the supercritical refrigeration cycle according to claim 1,
The flow rate adjusting valve switches from valve closing to valve opening when a temperature condition is established when the inlet refrigerant temperature to the low temperature side internal heat exchanger is higher than the inlet refrigerant temperature to the high temperature side internal heat exchanger, A supercritical refrigeration cycle characterized in that the refrigerant is set to flow in the bypass passage. 請求項１または請求項２に記載された超臨界冷凍サイクルにおいて、
前記バイパス通路は、前記アキュムレータから前記コンプレッサへと流れる低圧冷媒通路をバイパスする通路であり、
前記流量調整弁は、前記バイパス通路の入口部に設定され、前記アキュムレータからの冷媒温度による変形により通路開度を制御する弁体を有する第１流量調整弁と、前記バイパス通路の出口部に設定され、前記コンプレッサへの冷媒温度による変形により通路開度を制御する弁体を有する第２流量調整弁により構成したことを特徴とする超臨界冷凍サイクル。 In the supercritical refrigeration cycle according to claim 1 or 2,
The bypass passage is a passage that bypasses the low-pressure refrigerant passage that flows from the accumulator to the compressor,
The flow rate adjusting valve is set at an inlet portion of the bypass passage, and is set at a first flow rate adjusting valve having a valve body that controls a passage opening degree by deformation due to a refrigerant temperature from the accumulator, and an outlet portion of the bypass passage. A supercritical refrigeration cycle comprising a second flow rate adjustment valve having a valve body that controls passage opening by deformation due to refrigerant temperature to the compressor. 請求項３に記載された超臨界冷凍サイクルにおいて、
前記弁体は、少なくとも１箇所に冷媒通路となる通孔を設定したディスクを２枚重ね合わせた一対のディスクにより構成し、
前記一対のディスクは、２つの通孔が重ならないように位置決めし、冷媒温度が高温域では重ね合わせ部分が密着し、冷媒温度が低温域で重ね合わせ中央部分が開くように変形することを特徴とする超臨界冷凍サイクル。 In the supercritical refrigeration cycle according to claim 3,
The valve body is composed of a pair of disks in which two disks each having a through hole serving as a refrigerant passage are overlapped at least in one place,
The pair of disks are positioned so that the two through holes do not overlap each other, and are deformed so that the overlapping portion is in close contact when the refrigerant temperature is high and the overlapping central portion is open when the refrigerant temperature is low. Supercritical refrigeration cycle. 請求項４に記載された超臨界冷凍サイクルにおいて、
前記一対のディスクは、線膨張係数の異なる材質の板材を貼り合わせたバイメタルにより構成したことを特徴とする超臨界冷凍サイクル。 In the supercritical refrigeration cycle according to claim 4,
A supercritical refrigeration cycle characterized in that the pair of disks are made of a bimetal obtained by bonding plate materials made of materials having different linear expansion coefficients. 請求項４に記載された超臨界冷凍サイクルにおいて、
前記一対のディスクは、記憶温度を超えると記憶形状に変形する形状記憶合金により構成したことを特徴とする超臨界冷凍サイクル。 In the supercritical refrigeration cycle according to claim 4,
The supercritical refrigeration cycle characterized in that the pair of disks are made of a shape memory alloy that is deformed into a memory shape when the memory temperature is exceeded.
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