JP3601243B2

JP3601243B2 - Refrigeration cycle flow rate detection device

Info

Publication number: JP3601243B2
Application number: JP09241997A
Authority: JP
Inventors: 治雄神谷; 喜代治沓名; 英人稲垣; 昭則斎藤
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 1997-04-10
Filing date: 1997-04-10
Publication date: 2004-12-15
Anticipated expiration: 2017-04-10
Also published as: JPH10288431A

Description

【０００１】
【発明の属する技術分野】
本発明は、冷凍サイクルの圧縮機へ戻る潤滑油や液冷媒の流量を検出する流量検出装置に関するものである。
【０００２】
【従来の技術】
従来、上記した流量検出装置として、例えば特開平２−１４０５５７号公報には、冷凍サイクルのうち、気液分離器下流と膨張弁上流との間の液冷媒が流れる冷媒配管において、冷媒に混入されている潤滑油の潤滑油流量を検出するものが提案されている。この流量検出装置は、図７に示すように、アルミニウム材料からなる筒状ハウジング１００を備え、この内部に、透光円筒部材１０がシール部材１３、１４、１５、１６を介して密着するように、同軸的に嵌着されている。また、アルミニウム材料からなる小筒状ハウジング１０２が、筒状ハウジング１００に径方向に嵌合した状態でろう付け固定されており、この小筒状ハウジング１０２内部に光源２９が収容されている。光源２９は、定電圧を受けて紫外線を発光する。
【０００３】
また、アルミニウム材料からなる小筒状ハウジング１０３が筒状ハウジング１００に径方向に嵌合した状態でろう付け固定されており、この小筒状ハウジング１０３内部に光量検出器２０が収容されている。なお、小筒状ハウジング１０２、１０３の開口端部には、アルミニウム材料からなる蓋部材１０２ａ、１０３ａがビス１０４にて装着されている。
【０００４】
そして、ナフテン油等からなる潤滑油は、紫外線を受けて蛍光を発するアロマ基等の不飽和基を含むため、潤滑油は、紫外線を受けることにより不飽和基の流量に応じた蛍光を発し、この蛍光量を蛍光量検出器２０にて検出する。この蛍光量は潤滑油流量に比例するため、この蛍光量が所定値以下であるときに、圧縮機へ戻る潤滑油が不足している（つまり、圧縮機の潤滑性が不足する）と判定して圧縮機を停止している。
【０００５】
【発明が解決しようとする課題】
ところで、上記従来技術の流量検出装置では、膨張弁上流における潤滑油の流量を検出しているが、この流量検出装置と圧縮機との間に配置される膨張弁や蒸発器の運転条件は種々変化するので、実際に圧縮機に吸入される潤滑油の流量も、膨張弁や蒸発器の運転条件にて種々変化する。よって、流量検出装置による潤滑油の流量と、実際に圧縮機に吸入される潤滑油の流量との関係も種々変化するため、上記従来技術の流量検出装置にて検出される潤滑油の流量に関して、圧縮機の潤滑性を良好に保つことが可能な流量を一義的に決めることは困難であり、圧縮機における潤滑性不足を正確に判定できないことがわかった。
【０００６】
本発明は上記点に鑑みてなされたもので、圧縮機における潤滑性不足を正確に判定可能な流量検出装置を提供することを目的とする。
【０００７】
【課題を解決するための手段】
上記目的を達成するために、本発明者らは、圧縮機吸入側冷媒配管（Ｐ５、１０）を流れる潤滑油の流量を検出することを見出した。すなわち、請求項１ないし７に記載の発明では、光源（２９）からの光を圧縮機吸入側冷媒配管（Ｐ５、１０）内部へ入射させる第１透光部（１０Ａ）を、圧縮機吸入側冷媒配管（Ｐ５、１０）に気密に設け、圧縮機吸入側冷媒配管（Ｐ５、１０）内部を流れる潤滑油が第１透光部（１０Ａ）から入射された光を受けて発する蛍光を、圧縮機吸入側冷媒配管（Ｐ５、１０）外部へ出射させる第２透光部（１０Ｂ）を、圧縮機吸入側冷媒配管（Ｐ５、１０）に気密に設け、潤滑油の流量を、前記第２透光部（１０Ｂ）から出射される蛍光の光量として検出する蛍光量検出手段（２０）を設けたことを特徴としている。
【０００８】
このような構成によれば、蛍光量検出手段（２０）により、圧縮機吸入側冷媒配管（Ｐ５、１０）を流れる潤滑油の流量、つまり、圧縮機（１）が実際に吸い込む潤滑油の流量を検出できるので、この検出された潤滑油の流量に基づいて、圧縮機（１）における潤滑性不足を正確に判定でき、圧縮機（１）の潤滑不足による圧縮機（１）の故障を確実に防止できる。
【０００９】
なお、圧縮機吸入側冷媒配管（Ｐ５、１０）を流れる冷媒は、蒸発器（４）における熱交換性能の変動等により気相であったり気液二相であるため、光源（２９）からの光のうち圧縮機吸入側冷媒配管（Ｐ５、１０）内部を透過した透過光の変化量では潤滑油の流量変化を検出できない。これに対して本発明では、潤滑油が光を受けて発する蛍光の変化量によって潤滑油の流量変化を検出している。
【００１０】
また、本発明者らは、圧縮機吸入側冷媒配管（Ｐ５、１０）を流れる冷媒が、蒸発器（４）における熱交換性能の変動等により気相となったり気液二相となったりし、この冷媒が気液二相である場合、液冷媒により潤滑油が希釈されて圧縮機（１）の潤滑性が低下することに着目して、圧縮機吸入側の冷媒配管（Ｐ５、１０）を流れる液冷媒の流量も検出することを見出した。
【００１１】
すなわち、請求項２に記載の発明では、第１透光部（１０Ａ）から入射した光のうち圧縮機吸入側冷媒配管（Ｐ５、１０）内部を透過した光を、圧縮機吸入側冷媒配管（Ｐ５、１０）外部へ出射させる第３透光部（１０Ｃ）を、圧縮機吸入側冷媒配管（Ｐ５、１０）に気密に設け、透過光量検出手段（２８）により、液冷媒の流量を、第３透光部（１０Ｃ）から出射される透過光の光量として検出することを特徴としている。
【００１２】
このような構成によれば、透過光量検出手段（２８）により、圧縮機吸入側冷媒配管（Ｐ５、１０）を流れる液冷媒の流量を検出できる。このため、上述のように検出された潤滑油の流量に加えて、液冷媒の流量も考慮することができるので、圧縮機の潤滑性不足をより正確に判定でき、圧縮機の故障をより確実に防止できる。
【００１３】
また、請求項３に記載の発明では、上記光源を１つの光源（２９）から構成し、この１つの光源（２９）からの光を、第１透光部（１０Ａ）から入射させるとともに、第２透光部（１０Ｂ）および第３透光部（１０Ｃ）から出射させている。このように、光源（２９）を１つにすることにより、流量検出装置（Ｓ）が小型になるとともに、コスト安である。
【００１４】
また、請求項４に記載の発明では、光源（２９）からの光の進行経路（Ｄ）と、蛍光量検出手段（２０）の受光面の垂線（Ｔ）とが、鋭角的になるように、光源（２９）と蛍光量検出手段（２０）とを配置しているので、蛍光量検出手段（２０）に光源（２９）からの光が直接入射されることを良好に抑制でき、光源（２９）からの光を蛍光量検出手段（２０）にて検出することを抑制できる。
【００１５】
また、請求項５に記載の発明では、蛍光量検出手段（２０）と第２透光部（１０Ｂ）との間に、蛍光を主に透過するフィルタ部材（１９）を設けている。よって、蛍光以外の光（例えば、光源（２９）の光が第２透光部（１０Ｂ）にて反射した光等）が蛍光量検出手段（２０）に入射されるのを抑制できる。
また、請求項６に記載の発明では、蛍光量検出手段（２０）にて検出された蛍光量、および、透過光量検出手段（２８）にて検出された透過光量に基づいて、潤滑油と液冷媒との流量比を算出する流量比算出手段（１１０ａ）を備えている。よって、この算出された流量比に基づいて、圧縮機（１）の潤滑性不足を判定できる。
【００１６】
そして、圧縮機（１）の潤滑性不足を判定する手段として、請求項７に記載の発明では、蛍光量検出手段（２０）の検出値が所定値以下であるとき、および、流量比算出手段（１１０ａ）の算出値が所定値以下であるときのいずれか１つであるとき、圧縮機（１）が潤滑性不足であると判定する判定手段（１１０ａ）を設け、さらに、この判定手段（１１０ａ）にて圧縮機（１）の潤滑性不足が判定されたとき、圧縮機（１）を停止する圧縮機停止手段（１１０ｂ）を設けている。
【００１７】
よって、圧縮機（１）の潤滑性不足が判定されたときに圧縮機（１）を停止できるので、圧縮機（１）の故障を確実に防止できる。
【００１８】
【発明の実施の形態】
以下、本発明を図に示す実施形態について説明する。
本実施形態は、図１に示す車両用空調装置の冷凍サイクルにおいて、液冷媒の流量および潤滑油の流量を検出する流量検出装置に本発明を適用したものである。この冷凍サイクルには、適正量の冷媒（例えば、ＨＦＣ−１３４ａ）および適正量の潤滑油（コンプレッサオイル、例えば、ＰＡＧ油、合成油等）が封入されている。潤滑油には、適正量の蛍光材料が混入させてある。
【００１９】
なお、本実施形態では、蛍光材料として、蛍光の発光ピーク波長が５３０ｎｍ、主発光波長が５００〜５８０ｎｍの範囲内にあるもの（例えば、栄進化学製Ｌ−ＤＴ−Ｂ）を使用し、潤滑油に対して蛍光材料を０．０２５ｗｔ％混入させている。
冷凍サイクルは圧縮機１を備えており、この圧縮機１には、動力伝達を断続する電磁クラッチ１ａが装着されており、この電磁クラッチ１ａが接続状態になると、図示しない車両エンジンから動力が伝達されて圧縮機１は作動し、冷媒および潤滑油を吸入するとともに、潤滑作用を受けて冷媒を圧縮し、高温高圧のガス冷媒を潤滑油とともに吐出する。
【００２０】
圧縮機１から吐出された冷媒および潤滑油は凝縮器２に流入し、この凝縮器２において、図示しない冷却ファンによる空冷作用を受けて上記高温高圧のガス冷媒が凝縮される。この凝縮後の液冷媒は、潤滑油とともに受液器３内に流入する。この受液器３は、その内部に流入した凝縮冷媒を気液分離して、液冷媒のみを潤滑油とともに流出させる。
【００２１】
受液器３の下流側には、液冷媒を気液二相状態に減圧膨張させる膨張弁４が設けてあり、この膨張弁４を通過した低温低圧の冷媒は、潤滑油とともに蒸発器５へ流入し、蒸発する。そして、図示しない送風ファンにて蒸発器５へ送風される送風空気から冷媒の蒸発潜熱を吸熱することにより、送風空気を冷却し、この冷却した空気を車室内へ循環させて車室内の冷房をしている。膨張弁４は、周知のごとく、蒸発器５の出口冷媒の過熱度を所定値に維持するように弁開度が自動調整される温度式の膨張弁である。そして、蒸発器５にて蒸発させた冷媒を、潤滑油とともに再び圧縮機１に吸入させている。
【００２２】
なお、上記した圧縮機１、凝縮器２、受液器３、膨張弁４、蒸発器５は、冷媒配管Ｐ１、Ｐ２、Ｐ３、Ｐ４、Ｐ５にて相互に接続されている。そして、冷媒配管Ｐ５（つまり、蒸発器５下流で、圧縮機１上流の冷媒配管、圧縮機吸入側冷媒配管）の途中には、液冷媒の流量、および、潤滑油の流量を同時に検出する流量検出装置Ｓが装着されている。
【００２３】
次に、流量検出装置Ｓの具体的構造を図２および図３に基づいて説明する。
流量検出装置Ｓは、冷媒配管Ｐ５の途中に同軸的に組付けられている。この流量検出装置Ｓは、硼珪酸ガラス、石英ガラス、アルミノ珪酸ガラス等の透明耐圧材料からなる透光円筒部材１０を備えている。硼珪酸ガラス、石英ガラス、アルミノ珪酸ガラス等は、後述する光源２９からの紫外線の透過率が高いため、この検出装置Ｓの検出精度が良好となる。また、破壊強度も大きいため、この透光円筒部材１０の厚みを薄くでき、装置Ｓの小型化を図ることができる。
【００２４】
この透光円筒部材１０の一端部１０ａ、他端部１０ｂには、アルミニウム材料からなる円筒状ハウジング１１、１２の一端部１１ａ、１２ａが外嵌されている。透光円筒部材１０の一端部１０ａ、他端部１０ｂ側外周と、円筒状ハウジング１１、１２の一端部１１ａ、１２ａ側内周との間は、ゴム製の（弾性材料からなる）パッキン１４、１６にてシールされている。また、円筒状ハウジング１１、１２の一端部１１ａ、１２ａ側に形成された段付き部１１１、１２１に、透光円筒部材１０の一端部１０ａ、他端部１０ｂがゴム製のパッキン１３、１５を介して弾性的に支持されている。
【００２５】
ここで、冷媒配管Ｐ５は、流量検出装置Ｓが挿入可能となるように、蒸発器側冷媒配管Ｐ５１と圧縮機側冷媒配管Ｐ５２とに、所定距離を隔てて分離されている。冷媒配管Ｐ５１、Ｐ５２の端部はフレアー状となっており、ネジ孔を備えたナット５０が外嵌されている。そして、冷媒配管Ｐ５１、Ｐ５２の端部と、円筒状ハウジング１１、１２の他端部１１ｂ、１２ｂとを当接させ、ナット５０を、円筒状ハウジング１１、１２の他端部１１ｂ、１２ｂに形成されたネジ山１１ｃ、１２ｃにネジ結合することにより、冷媒配管Ｐ５１、Ｐ５２の端部と、円筒状ハウジング１１、１２の他端部１１ｂ、１２ｂとをメタルシールしている。
【００２６】
この冷媒配管Ｐ５１、Ｐ５２の内径と、円筒状ハウジング１１、１２の内径と、透光円筒部材１０の内径は、全て統一されている。これにより、流量検出装置Ｓを冷媒配管Ｐ５の途中に装着することによる冷媒流れの圧損を最小限に抑えている。
円筒状ハウジング１１、１２の外周部全周には、径方向外方へ延びるフランジ部１１２、１２２が一体に備えられている。このフランジ部１１２、１２２は、正面外形状が略正方形であり、このフランジ部１１２、１２２間には、アルミニウム材料からなる４つの長尺板状ハウジング１７、１８、２４、２５（ハウジング２４、２５は、図３参照）が設けられている。
【００２７】
そして、ハウジング１７、１８の両端部は、フランジ部１１２、１２２にボルト３０にて締結されている。この両端部とフランジ部１１２、１２２との間は、図示しないシール部材にてシールされている。また、図３に示すように、ハウジング１７、１８の長手方向に沿った両側端面に、ハウジング２４、２５の長手方向に沿った両側端面側が、ボルト３０にて締結されている。このハウジング１７、１８の両側端面とハウジング２４、２５の両側端面側とは、シール部材３１、３２にてシールされている。
【００２８】
そして、上記した円筒状ハウジング１１、１２と、ハウジング１７、１８、２４、２５とにより、透光円筒部材１０の周囲に密閉空間Ｃを形成するカバー部材１００を構成している。
ハウジング２４には、光源２９を収容する光源収容部２４ａが形成されており、この光源２９の出光方向後方には、光学フィルタ２６およびフォトセンサ２７を収容する収容部２４ｂが形成されている。光源収容部２４ａと収容部２４ｂとの間には、光源２９の紫外線が光学フィルタ２６およびフォトセンサ２７に対して斜めに入射されるような紫外線通路形成部２４ｃが形成してある。
【００２９】
光源２９は、図示しない定電圧電源から定電圧を受けて紫外線を発光するものである。この光源２９は、図４に示すように、アルミニウム製の本体部２９０と、本体部２９０に支持される水銀ランプ２９１（例えば、浜松ホトニクス製Ｌ１５４９−０４）とを備えている。この水銀ランプ２９１のガラス内壁には蛍光剤が塗られており、この蛍光剤は、２５４ｎｍの水銀スペクトルにて励起されることにより、ピーク波長が３５１ｎｍ、主発光波長域が３００〜４００ｎｍの紫外線を発光する。つまり、この紫外線が、水銀ランプ２９１の発する光である。なお、２５４ｎｍの水銀スペクトルは人体に有害であるが、蛍光剤にて吸収されるために、２５４ｎｍの水銀スペクトルがかなり低減される。
【００３０】
光学フィルタ２６は、光源２９からの光のうち、所定波長（例えば、２８０〜４００ｎｍ）の光のみを透過させるものであり、最大透過率の波長が３５５ｎｍ、最大透過率が４７％、半値幅が５５ｎｍの紫外線透過可視吸収フィルタからなる（例えば、東芝硝子製ＵＶ−Ｄ３６Ａ）。この光学フィルタ２６は、厚さが例えば３ｍｍ程度のガラス板であるが、この光学フィルタ２６を、収容部２４ｂに形成される支持部２４ｄに支持させつつ、ゴム製パッキン３４にて弾性的に支持することにより、検出装置Ｓに加わる外的衝撃等により光学フィルタ２６が破損するのを抑制している。
【００３１】
フォトセンサ２７は、光学フィルタ２６を通過した紫外線の強度を検出するものであり、紫外域から可視域までを精度よく測定でき、かつ、赤外感度が抑制された板状のシリコンフォトダイオード（例えば、浜松ホトニクス製Ｓ１２２７−１６ＢＲ）からなる。このフォトセンサ２７の受光面（図３中右側面）を光源２９に対向させるとともに、この受光面が光学フィルタ２６に接着固定されている。
【００３２】
なお、光源２９からの光は、透光円筒部材１０にて反射して、さらにこの反射光が光学フィルタ２６にて反射する恐れがあり、このため、フォトセンサ２７を光学フィルタ２６から離して設けると、フォトセンサ２７に、光学フィルタ２６からの反射光が入射されて、紫外線の強度を精度よく検出できなくなる恐れがある。これに対して本実施形態では、フォトセンサ２７を光学フィルタ２６に接着固定することにより、上記恐れを防止している。
【００３３】
また、光源２９からの紫外線は光源２９近傍の温度変化によって出力特性が変化するため、フォトセンサ２７にて光源２９からの紫外線の強度を測定し、後述するフォトセンサ２０、２８の検出値の補正を行なうようにしている。具体的には、フォトセンサ２０、２８の検出値を、フォトセンサ２７の検出値にて割ることにより、補正している。
【００３４】
ハウジング２４とシール部材３１との間には、遮光性および剛性を有する材料（例えば鉄）からなる遮光支持板３３が配置されている。なお、ハウジング２４と遮光支持板３３、および、遮光支持板３３とシール部材３１とは、接着されている。遮光支持板３３には、光源２９の光を透光円筒部材１０の第１透光部１０Ａへ照射するための透光窓３３０が開口形成されている。この第１透光部１０Ａを透過した光は、透光円筒部材１０内部に入射される。なお、第１透光部１０Ａとは、透光円筒部材１０のうち光源２９の光が入射される部位のことである。
【００３５】
また、ハウジング１７には、光学フィルタ（フィルタ部材）１９、フォトセンサ（蛍光量検出手段）２０、および、ゴム製の絶縁シール部材２１を重ねて収容する収容部１７ａが形成されている。
収容部１７ａのうち、透光円筒部材１０側部位の内壁に形成された枠状の支持部１７ｂと、収容部１７ａのうち、透光円筒部材１０の反対側部位を覆う金属製（例えばアルミニウム）の押さえ板２２との間に、光学フィルタ１９、フォトセンサ２０、および、絶縁シール部材２１が、順に配置されて支持されている。押さえ板２２は、ボルト２３にて長尺厚板状ハウジング１７に装着されている。
【００３６】
そして、第１透光部１０Ａから入射された光を潤滑油が受けて発する蛍光が、透光円筒部材１０の第２透光部１０Ｂを経て、光学フィルタ１９およびフォトセンサ２０へ入射される。なお、第２透光部１０Ｂとは、透光円筒部材１０のうち、支持部１７ｂの内側に形成される矩形状の開口部１７ｃに入射される光を出射する部位であり、開口部１７ｃに対向する部位およびその近傍である。
【００３７】
光学フィルタ１９は、透光円筒部材１０からの光のうち、所定波長（例えば、４８０〜６００ｎｍ）の光を主に透過させるものであり、最大透過率の波長が５３０ｎｍ、最大透過率が４２％、半値幅が４８ｎｍのバンドパスフィルタ（例えば、富士写真フィルム製ＢＰＮ−５３）からなる。この光学フィルタ１９は、厚さが例えば０．２ｍｍ程度のトリアセテートを主成分とする板状フィルタである。そして、光学フィルタ１９の受光面（図３中下面）を透光円筒部材１０の第２透光部１０Ｂに対向させている。ここで、光学フィルタ１９の受光面、つまり、フォトセンサ２０の受光面（図３中下面）の垂線Ｔと、紫外線通路形成部２４ｃにて形成される光源２９の進行経路Ｄとが、鋭角的に配置されるように、光源２９、光学フィルタ１９、および、フォトセンサ２０が配置されている。この結果、フォトセンサ２０に光源２９からの光が直接入射されることを良好に抑制でき、光源２９からの光をフォトセンサ２０にて検出することを防止できる。
【００３８】
なお、波長が４８０〜６００ｎｍの光を主に透過させる光学フィルタ１９により、波長が２８０〜４００ｎｍの光を主に透過させる光学フィルタ２６を透過した光が、フォトセンサ２０へ入射されるのを抑制できる。よって、光学フィルタ２６を透過した光と、後述する潤滑油からの蛍光とを良好に分離できる。よって、このフォトセンサ２０の検出精度は良好である。また、フォトセンサ２０は、光学フィルタ１９を通過した蛍光の蛍光強度Ａを検出するものであり、紫外域から可視域までを精度よく測定でき、かつ、赤外感度が抑制されたシリコンフォトダイオード（例えば、浜松ホトニクス製Ｓ１２２７−１０１０ＢＲ）からなる。
【００３９】
また、ハウジング２５のうち、透光円筒部材１０を中心にして光源２９と点対称な位置には、フォトセンサ（透過光量検出手段）２８を収容する収容部２５ａが形成されている。ハウジング２５とパッキン３２との間には、遮光性および剛性を有する材料（例えば鉄）からなり、フォトセンサ２８を支持する遮光支持板３５が配置されている。この遮光支持板３５には、フォトセンサ２８に光を入射可能とする開口部３５０が形成されており、この開口部３５０の縁部にてフォトセンサ２８の外周部を支持している。なお、ハウジング２５と遮光支持板３５、および、遮光支持板３５とパッキン３２とは接着されている。
【００４０】
フォトセンサ２８は、透光円筒部材１０からの光（透過光）の透過光強度Ｂを検出するものであり、上記したフォトセンサ２０と同様のシリコンフォトダイオードからなる。そして、第１透光部１０Ａから入射された光のうち透光円筒部材１０内部を透過した光（つまり、液冷媒および潤滑油に吸収および散乱されなかった光）が、第３透光部１０Ｃを経て、フォトセンサ２８（つまり、遮光支持板３５の開口部３５内側）に入射される。
【００４１】
上記したフォトセンサ２０、２７、２８は、図示しない一対のリード端子を有し、このリード端子を、図示しないアンプに繋ぐことにより、フォトセンサ２０、２７、２８の受光電圧を検出するようになっている。また、透光円筒部材１０は、請求項でいう第１、第２、第３透光部を構成するとともに、圧縮機吸入側冷媒配管をも構成している。
【００４２】
ここで、第２透光部１０Ｂから出射される蛍光の蛍光強度Ａと、透光円筒部材１０を流れる潤滑油の流量Ｑ（つまり、潤滑油に含まれる蛍光材料の流量）とは、図５のグラフに示すような関係にある。つまり、透光円筒部材１０を流れる潤滑油は、入射紫外線により流量Ｑに比例した蛍光強度Ａをもって蛍光（５００〜５８０ｎｍの主発光波長を持つ）を散乱的に発し、この蛍光がフォトセンサ２０に入射される。そして、フォトセンサ２０は、蛍光強度Ａをもった蛍光を受光することにより、受光電圧Ｖを生じる。
【００４３】
また、第３透光部１０Ｃから出射される透過光の透過光強度Ｂと、透光円筒部材１０を流れる液冷媒の流量Ｒとは、図６のグラフに示すような関係にある。つまり、透光円筒部材１０内を流れる液冷媒の流量Ｒに対応して透光円筒部材１０内における入射紫外線の散乱量が変化するために、透光円筒部材１０に入射される入射紫外線のうち透光円筒部材１０を透過して透光円筒部材１０からフォトセンサ２８へ向かって出射する光（透過光）は、液冷媒の流量Ｒに対応した透過光強度Ｂをもってフォトセンサ２８へ入射する。このフォトセンサ２８は、透過光強度Ｂをもった透過光を受光することにより、受光電圧Ｅを生じる。なお、潤滑油による紫外線の吸収量は、液冷媒による紫外線の散乱量に比べて非常に小さいため、第３透光部１０Ｃから出射される透過光の透過光強度Ｂにより、液冷媒の流量Ｒを検出できるのである。
【００４４】
そして、車両に搭載される電気制御装置（図１参照）１１０は、上記フォトセンサ２０、２８にて生じた受光電圧Ｖ、Ｅを読み込み、この読み込んだ情報に基づいて演算手段１１０ａにて演算を行い、この演算結果に基づいて、駆動制御手段１１０ｂにより電磁クラッチ１ａの接続状態（つまり、圧縮機１の作動停止）を駆動制御する。
【００４５】
以下に、演算手段１１０ａおよび駆動制御手段１１０ｂの作動を詳しく説明する。
まず、電気制御装置１１０のＲＯＭには、所定電圧Ｖ_０および所定電圧比Ｈ_０が予め記憶されている。上記所定電圧Ｖ_０は所定蛍光強度Ａ_０に対応し、この所定蛍光強度Ａ_０は、圧縮機１の潤滑性不足を招く潤滑油流量の上限値である所定流量Ｑ_０（例えば、１ｋｇ／ｈ）に対応する。上記所定電圧比Ｈ_０は所定光強度比に対応し、この所定光強度比は、圧縮機１の潤滑性不足を招く潤滑油と液冷媒との流量比（潤滑油流量／液冷媒流量）の上限値である所定流量比（例えば、１／１０）に対応する。
【００４６】
そして、演算手段１１０ａは、受光電圧Ｖと受光電圧Ｅとの電圧比（受光電圧Ｖ／受光電圧Ｅ）Ｈを算出して、この電圧比Ｈと所定電圧比Ｈ_０とを比較するとともに、受光電圧Ｖと所定電圧Ｖ_０とを比較する。なお、演算手段１１０ａは、上記電圧比Ｈを算出することにより、潤滑油と液冷媒との流量比（潤滑油流量／液冷媒流量）を算出する流量比算出手段を構成している。
【００４７】
そして、演算手段１１０ａにより、Ｖ＞Ｖ_０（つまり、潤滑油の流量Ｑが上記所定流量Ｑ_０よりも大きい）であり、かつ、Ｈ＞Ｈ_０（つまり、潤滑油と液冷媒との流量比が、上記所定流量比よりも大きい）であると判定されると、圧縮機１の潤滑が良好に行なわれると判定して、駆動制御手段１１０ｂは、圧縮機１の電磁クラッチ１ａを接続状態とする接続用信号を発生する。これにより、電磁クラッチ１ａが接続状態となり、圧縮機１が作動する。
【００４８】
また、演算手段１１０ａにより、Ｖ≦Ｖ_０（つまり、潤滑油の流量Ｑが上記所定流量Ｑ_０以下である）、および、Ｈ≦Ｈ_０（つまり、潤滑油と液冷媒との流量比が、上記所定流量比以下である）のいずれか一方が判定されると、圧縮機１が潤滑性不足であると判定し、この判定を受けて駆動制御手段１１０ｂは、圧縮機１の電磁クラッチ１ａを非接続状態とする非接続用信号を発生する。これにより、電磁クラッチ１ａが非接続状態となり、圧縮機１が停止する。
【００４９】
そして、冷媒配管Ｐ５を流れる潤滑油の流量に対応するフォトセンサ２０の受光電圧Ｖに基づいて、圧縮機１における潤滑性不足を正確に判定できるので、圧縮機１の潤滑性不足による圧縮機１の故障を確実に防止できる。
また、フォトセンサ２０の受光電圧Ｖに加えて、冷媒配管Ｐ５を流れる液冷媒の流量に対応するフォトセンサ２８の受光電圧Ｅも検出することにより、圧縮機の潤滑性不足をより正確に判定でき、圧縮機１の故障をより確実に防止できる。
【００５０】
なお、演算手段１１０ａは、Ｖ≦Ｖ_０およびＨ≦Ｈ_０のいずれか一方であるとき、圧縮機１が潤滑性不足であると判定する判定手段を構成している。また、駆動制御手段１１０ｂは、演算手段１１０ａにて圧縮機１の潤滑性不足が判定されたとき、圧縮機１を停止する圧縮機停止手段を構成している。
（他の実施形態）
まず、透光円筒部材１０の表面およびカバー部材１００の内壁面において、光源２９からの光が反射してフォトセンサ２０、２７、２８側へ入射されるのを抑制するために、透光円筒部材１０の表面およびカバー部材１００の内壁面に、反射防止層を形成してもよい。具体的には、透光円筒部材１０の表面やカバー部材１００の内壁面に、黒色系の光吸収層を形成してもよいし、透光円筒部材１０の表面やカバー部材１００の内壁面に、光を乱反射させる光拡散層を形成してもよい。
【００５１】
また、上記実施形態では、潤滑油の流量Ｑの減少や、上記流量比の減少により圧縮機１を停止していたが、他の種々の制御を行なってもよい。例えば、蒸発器５に送風する送風量を増加して熱交換を促進し、蒸発器５における冷媒蒸発量を増加させてもよいし、膨張弁４により、膨張弁開度を小さくして冷媒流量を減少させて冷媒を完全に蒸発させてもよいし、膨張弁開度を大きくして潤滑油流量を増加させてもよい。
【００５２】
また、液冷媒の流量Ｒが多いと、圧縮機１の吸い込み作動が良好に行なわれなくなることに着目して、受光電圧Ｅを所定電圧Ｅ_０と比較することにより、圧縮機１の作動停止を制御してもよい。なお、所定電圧Ｅ_０は所定透過光強度Ｂ_０に対応し、この所定透過光強度Ｂ_０は、圧縮機１の吸い込み作動が良好に行なわれなくなるような液冷媒の流量の上限値である所定流量Ｒ_０（例えば、１０ｋｇ／ｈ）に対応する。
【００５３】
また、上記実施形態では、第３透光部１０Ｃから出射される透過光の透過光強度Ｂを、液冷媒の流量に対応させて検出していたが、第３透光部１０Ｃから出射される透過光の透過光強度Ｂを、液冷媒および潤滑油の流量に対応させて検出し、この検出値と、蛍光強度Ａにて検出される潤滑油の流量とを用いて、圧縮機１の潤滑性を良好に保つよう制御してもよい。
【００５４】
また、実験室内に配置される実験用の冷凍サイクルに本発明の流量検出装置Ｓを適用してもよい。
【図面の簡単な説明】
【図１】本発明の冷凍サイクルの全体構成図および電気ブロック図である。
【図２】本発明の第１の実施形態の流量検出装置の断面図である。
【図３】図２のＡ−Ａ断面図である。
【図４】第１の実施形態における流量検出装置の構成部品の配置関係を示す図である。
【図５】潤滑油の流量と蛍光強度との関係を示すグラフである。
【図６】液冷媒の流量と透過光強度との関係を示すグラフである。
【図７】従来技術に係わる流量検出装置の断面図である。
【符号の説明】
１…圧縮機、２…凝縮器、４…膨張弁、５…蒸発器、
Ｐ５…冷媒配管（圧縮機吸入側冷媒配管）、１０…透光円筒部材、
１０Ａ、１０Ｂ、１０Ｃ…第１、第２、第３透光部、２９…光源、
２０…フォトセンサ（蛍光量検出手段）、
２８…フォトセンサ（透過光量検出手段）。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flow rate detection device for detecting a flow rate of lubricating oil and liquid refrigerant returning to a compressor of a refrigeration cycle.
[0002]
[Prior art]
Conventionally, as the above-mentioned flow rate detecting device, for example, Japanese Patent Application Laid-Open No. 2-140557 discloses that in a refrigeration cycle, liquid refrigerant is mixed with refrigerant in a refrigerant pipe in which liquid refrigerant flows between a gas-liquid separator downstream and an expansion valve upstream. One that detects the lubricating oil flow rate of the lubricating oil has been proposed. As shown in FIG. 7, this flow rate detection device includes a cylindrical housing 100 made of an aluminum material, and the light transmitting cylindrical member 10 is tightly fitted inside the cylindrical housing 100 via sealing members 13, 14, 15, 16. , Are coaxially fitted. A small cylindrical housing 102 made of an aluminum material is brazed and fixed to the cylindrical housing 100 in a state of being fitted in the radial direction, and the light source 29 is accommodated inside the small cylindrical housing 102. The light source 29 emits ultraviolet light upon receiving a constant voltage.
[0003]
Further, a small cylindrical housing 103 made of aluminum material is brazed and fixed to the cylindrical housing 100 in a state of being fitted in the radial direction, and the light amount detector 20 is housed inside the small cylindrical housing 103. Note that lid members 102a and 103a made of aluminum material are attached to the open ends of the small cylindrical housings 102 and 103 with screws 104.
[0004]
And, since the lubricating oil composed of naphthenic oil or the like contains unsaturated groups such as aroma groups that emit fluorescence upon receiving ultraviolet rays, the lubricating oil emits fluorescence according to the flow rate of the unsaturated groups upon receiving ultraviolet rays, This fluorescence amount is detected by the fluorescence amount detector 20. Since the amount of the fluorescent light is proportional to the flow rate of the lubricating oil, when the amount of the fluorescent light is equal to or less than a predetermined value, it is determined that the lubricating oil returning to the compressor is insufficient (that is, the lubricity of the compressor is insufficient). The compressor is stopped.
[0005]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional flow rate detecting device, the flow rate of the lubricating oil upstream of the expansion valve is detected. However, operating conditions of the expansion valve and the evaporator disposed between the flow rate detecting device and the compressor are various. Therefore, the flow rate of the lubricating oil actually sucked into the compressor also changes variously depending on the operating conditions of the expansion valve and the evaporator. Therefore, since the relationship between the flow rate of the lubricating oil by the flow rate detecting device and the flow rate of the lubricating oil actually sucked into the compressor also changes variously, the flow rate of the lubricating oil detected by the above-described conventional flow rate detecting device is changed. It has been found that it is difficult to unambiguously determine the flow rate at which the lubrication of the compressor can be maintained satisfactorily, and it is not possible to accurately determine insufficient lubrication in the compressor.
[0006]
The present invention has been made in view of the above, and an object of the present invention is to provide a flow rate detection device capable of accurately determining insufficient lubrication in a compressor.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present inventors have found that the flow rate of lubricating oil flowing through the compressor suction-side refrigerant pipes (P5, P10) is detected. That is, according to the first to seventh aspects of the present invention, the first light transmitting portion (10A) for causing the light from the light source (29) to enter the inside of the compressor suction side refrigerant pipe (P5, 10) is connected to the compressor suction side. Lubricating oil is provided in the refrigerant pipes (P5, 10) in an airtight manner, and the lubricating oil flowing inside the compressor suction-side refrigerant pipes (P5, 10) compresses the fluorescence emitted by receiving the light incident from the first light transmitting portion (10A). A second light-transmitting portion (10B) for emitting light to the outside of the compressor suction-side refrigerant pipes (P5, 10) is provided in the compressor suction-side refrigerant pipes (P5, 10) in an airtight manner, and the flow rate of the lubricating oil is controlled by the second transmission section. It is characterized in that a fluorescent light amount detecting means (20) for detecting the amount of fluorescent light emitted from the light section (10B) is provided.
[0008]
According to such a configuration, the flow rate of the lubricating oil flowing through the compressor suction side refrigerant pipes (P5, 10), that is, the flow rate of the lubricating oil actually sucked by the compressor (1), is detected by the fluorescence amount detecting means (20). Can be accurately determined on the basis of the detected flow rate of the lubricating oil, and the lack of lubricity in the compressor (1) can be accurately determined, and the failure of the compressor (1) due to the lack of lubrication in the compressor (1) can be reliably determined. Can be prevented.
[0009]
Since the refrigerant flowing through the compressor suction-side refrigerant pipes (P5, 10) is in a gas phase or a gas-liquid two-phase due to a change in heat exchange performance in the evaporator (4), the refrigerant from the light source (29) A change in the flow rate of the lubricating oil cannot be detected based on the amount of change in the transmitted light of the light that has passed through the compressor suction side refrigerant pipes (P5, 10). On the other hand, in the present invention, the change in the flow rate of the lubricating oil is detected based on the amount of change in the fluorescence emitted by the lubricating oil receiving light.
[0010]
In addition, the present inventors have found that the refrigerant flowing through the compressor suction side refrigerant pipes (P5, 10) becomes gas phase or gas-liquid two-phase due to fluctuations in heat exchange performance in the evaporator (4). When this refrigerant is in a gas-liquid two-phase state, paying attention to the fact that the lubricating oil is diluted by the liquid refrigerant and the lubricity of the compressor (1) is reduced, the refrigerant piping (P5, 10) on the compressor suction side It has also been found that the flow rate of the liquid refrigerant flowing through is also detected.
[0011]
That is, in the invention described in claim 2, light transmitted through the inside of the compressor suction side refrigerant pipe (P5, 10) among the light incident from the first light transmitting portion (10A) is converted into the compressor suction side refrigerant pipe ( P5, 10) A third light-transmitting portion (10C) for emitting light to the outside is provided in the compressor suction-side refrigerant pipe (P5, 10) in an airtight manner, and the transmitted light amount detecting means (28) controls the flow rate of the liquid refrigerant to the third level. It is characterized in that it is detected as the amount of transmitted light emitted from the three light transmitting portions (10C).
[0012]
According to such a configuration, the flow rate of the liquid refrigerant flowing through the compressor suction side refrigerant pipes (P5, 10) can be detected by the transmitted light amount detection means (28). For this reason, in addition to the flow rate of the lubricating oil detected as described above, the flow rate of the liquid refrigerant can be considered, so that the lack of lubricity of the compressor can be determined more accurately, and the failure of the compressor can be more reliably determined. Can be prevented.
[0013]
Further, in the invention according to claim 3, the light source is constituted by one light source (29), and the light from the one light source (29) is made to enter from the first light transmitting portion (10A). The light is emitted from the second light transmitting portion (10B) and the third light transmitting portion (10C). Thus, by using only one light source (29), the flow rate detection device (S) can be reduced in size and cost can be reduced.
[0014]
Further, in the invention according to claim 4, the traveling path (D) of the light from the light source (29) and the perpendicular (T) of the light receiving surface of the fluorescence amount detecting means (20) are formed to be acute. Since the light source (29) and the fluorescence amount detecting means (20) are arranged, it is possible to satisfactorily prevent the light from the light source (29) from directly entering the fluorescence amount detecting means (20). It is possible to suppress the detection of the light from (29) by the fluorescence amount detection means (20).
[0015]
According to the fifth aspect of the present invention, a filter member (19) that mainly transmits fluorescence is provided between the fluorescence amount detection means (20) and the second light transmitting portion (10B). Therefore, it is possible to prevent light other than the fluorescent light (for example, the light of the light source (29) reflected by the second light transmitting portion (10B)) from being incident on the fluorescent light amount detecting means (20).
Further, in the invention according to claim 6, the lubricating oil and the liquid are determined based on the amount of fluorescence detected by the amount of fluorescence detecting means (20) and the amount of transmitted light detected by the transmitted light amount detecting means (28). A flow ratio calculating means (110a) for calculating a flow ratio with the refrigerant is provided. Therefore, it is possible to determine the lack of lubricity of the compressor (1) based on the calculated flow ratio.
[0016]
In the invention according to claim 7, when the detected value of the fluorescent light amount detecting means (20) is equal to or less than a predetermined value, and as a means for determining the insufficient lubricating property of the compressor (1), When the calculated value of (110a) is equal to or less than a predetermined value, a judging means (110a) for judging that the compressor (1) has insufficient lubrication is provided. A compressor stop means (110b) for stopping the compressor (1) when it is determined in 110a) that the lubricity of the compressor (1) is insufficient is provided.
[0017]
Therefore, the compressor (1) can be stopped when it is determined that the lubricity of the compressor (1) is insufficient, so that the failure of the compressor (1) can be reliably prevented.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention shown in the drawings will be described.
In the present embodiment, the present invention is applied to a flow rate detection device that detects a flow rate of a liquid refrigerant and a flow rate of a lubricating oil in the refrigeration cycle of the vehicle air conditioner shown in FIG. This refrigeration cycle is filled with an appropriate amount of refrigerant (for example, HFC-134a) and an appropriate amount of lubricating oil (compressor oil, for example, PAG oil, synthetic oil, etc.). An appropriate amount of fluorescent material is mixed in the lubricating oil.
[0019]
In the present embodiment, a fluorescent material having an emission peak wavelength of fluorescence in the range of 530 nm and a main emission wavelength in the range of 500 to 580 nm (for example, L-DT-B manufactured by Eishin Chemical Co., Ltd.) is used as the fluorescent material. 0.025% by weight of a fluorescent material is mixed in.
The refrigerating cycle includes a compressor 1, and an electromagnetic clutch 1a for interrupting power transmission is mounted on the compressor 1. When the electromagnetic clutch 1a is connected, power is transmitted from a vehicle engine (not shown). Then, the compressor 1 operates to suck the refrigerant and the lubricating oil, compress the refrigerant under the lubricating action, and discharge the high-temperature and high-pressure gas refrigerant together with the lubricating oil.
[0020]
The refrigerant and the lubricating oil discharged from the compressor 1 flow into the condenser 2, where the high-temperature and high-pressure gas refrigerant is condensed by an air cooling action by a cooling fan (not shown). The condensed liquid refrigerant flows into the liquid receiver 3 together with the lubricating oil. The liquid receiver 3 gas-liquid separates the condensed refrigerant that has flowed into the liquid receiver 3, and allows only the liquid refrigerant to flow out together with the lubricating oil.
[0021]
On the downstream side of the receiver 3, an expansion valve 4 for reducing and expanding the liquid refrigerant into a gas-liquid two-phase state is provided. The low-temperature and low-pressure refrigerant passing through the expansion valve 4 is sent to the evaporator 5 together with the lubricating oil. Enter and evaporate. Then, by cooling the blown air by absorbing the latent heat of evaporation of the refrigerant from the blown air blown to the evaporator 5 by a blower fan (not shown), the cooled air is circulated into the vehicle interior to cool the vehicle interior. are doing. As is well known, the expansion valve 4 is a temperature-type expansion valve whose valve opening is automatically adjusted so that the degree of superheat of the refrigerant at the outlet of the evaporator 5 is maintained at a predetermined value. Then, the refrigerant evaporated by the evaporator 5 is sucked into the compressor 1 again together with the lubricating oil.
[0022]
The compressor 1, the condenser 2, the liquid receiver 3, the expansion valve 4, and the evaporator 5 are connected to each other by refrigerant pipes P1, P2, P3, P4, and P5. In the middle of the refrigerant pipe P5 (that is, the refrigerant pipe downstream of the evaporator 5 and upstream of the compressor 1, and the refrigerant suction-side refrigerant pipe), the flow rate of the liquid refrigerant and the flow rate of the lubricating oil are simultaneously detected. The detection device S is mounted.
[0023]
Next, a specific structure of the flow rate detection device S will be described with reference to FIGS.
The flow rate detection device S is coaxially mounted in the middle of the refrigerant pipe P5. The flow rate detection device S includes a light-transmitting cylindrical member 10 made of a transparent pressure-resistant material such as borosilicate glass, quartz glass, or aluminosilicate glass. Since borosilicate glass, quartz glass, aluminosilicate glass, and the like have a high transmittance of ultraviolet rays from a light source 29 described later, the detection accuracy of the detection device S is improved. Further, since the breaking strength is high, the thickness of the light-transmitting cylindrical member 10 can be reduced, and the size of the device S can be reduced.
[0024]
One end portions 11a and 12a of cylindrical housings 11 and 12 made of an aluminum material are fitted to one end portion 10a and the other end portion 10b of the light transmitting cylindrical member 10, respectively. A packing 14 made of rubber (made of an elastic material) is provided between an outer periphery of one end 10 a and the other end 10 b of the light transmitting cylindrical member 10 and an inner periphery of one end 11 a and 12 a of the cylindrical housings 11 and 12. Sealed at 16. In addition, packings 13, 15 made of rubber are used for the one end 10 a and the other end 10 b of the light-transmitting cylindrical member 10 on the stepped parts 111, 121 formed on the one end 11 a, 12 a side of the cylindrical housing 11, 12. It is elastically supported through.
[0025]
Here, the refrigerant pipe P5 is separated by a predetermined distance from the evaporator-side refrigerant pipe P51 and the compressor-side refrigerant pipe P52 so that the flow rate detection device S can be inserted. The ends of the refrigerant pipes P51 and P52 are in a flare shape, and a nut 50 having a screw hole is externally fitted. Then, the ends of the refrigerant pipes P51 and P52 are brought into contact with the other ends 11b and 12b of the cylindrical housings 11 and 12, and the nut 50 is formed on the other ends 11b and 12b of the cylindrical housings 11 and 12. The ends of the refrigerant pipes P51 and P52 and the other ends 11b and 12b of the cylindrical housings 11 and 12 are metal-sealed by screwing the screw threads 11c and 12c.
[0026]
The inner diameters of the refrigerant pipes P51 and P52, the inner diameters of the cylindrical housings 11 and 12, and the inner diameter of the light transmitting cylindrical member 10 are all unified. Thereby, the pressure loss of the refrigerant flow caused by mounting the flow rate detection device S in the middle of the refrigerant pipe P5 is minimized.
Flanges 112, 122 extending outward in the radial direction are integrally provided on the entire outer periphery of the cylindrical housings 11, 12. The flange portions 112 and 122 have a substantially square front outer shape, and four long plate-shaped housings 17, 18, 24 and 25 made of aluminum material are provided between the flange portions 112 and 122 (housings 24 and 25). Is provided in FIG. 3).
[0027]
Both ends of the housings 17 and 18 are fastened to the flange portions 112 and 122 with bolts 30. The space between the both ends and the flange portions 112 and 122 is sealed by a seal member (not shown). As shown in FIG. 3, bolts 30 fasten both end surfaces of the housings 24, 25 along the longitudinal direction to both end surfaces of the housings 17, 18 along the longitudinal direction. Both end surfaces of the housings 17 and 18 and both end surfaces of the housings 24 and 25 are sealed by seal members 31 and 32.
[0028]
The cylindrical housings 11 and 12 and the housings 17, 18, 24 and 25 constitute a cover member 100 that forms a closed space C around the light transmitting cylindrical member 10.
The housing 24 has a light source accommodating portion 24 a for accommodating the light source 29, and an accommodating portion 24 b for accommodating the optical filter 26 and the photosensor 27 is formed behind the light source 29 in the light emitting direction. An ultraviolet passage forming portion 24c is formed between the light source housing portion 24a and the housing portion 24b so that the ultraviolet light of the light source 29 is obliquely incident on the optical filter 26 and the photosensor 27.
[0029]
The light source 29 emits ultraviolet light upon receiving a constant voltage from a constant voltage power supply (not shown). As shown in FIG. 4, the light source 29 includes a main body 290 made of aluminum and a mercury lamp 291 (for example, L1549-04 manufactured by Hamamatsu Photonics) supported by the main body 290. A fluorescent agent is coated on the inner wall of the glass of the mercury lamp 291. When the fluorescent agent is excited by a mercury spectrum of 254 nm, the fluorescent agent emits ultraviolet light having a peak wavelength of 351 nm and a main emission wavelength range of 300 to 400 nm. It emits light. That is, the ultraviolet light is light emitted from the mercury lamp 291. Although the mercury spectrum at 254 nm is harmful to the human body, the mercury spectrum at 254 nm is considerably reduced because it is absorbed by the fluorescent agent.
[0030]
The optical filter 26 transmits only light having a predetermined wavelength (for example, 280 to 400 nm) out of the light from the light source 29. The wavelength of the maximum transmittance is 355 nm, the maximum transmittance is 47%, and the half width is It consists of a 55 nm ultraviolet transmission visible absorption filter (for example, UV-D36A manufactured by Toshiba Glass). The optical filter 26 is a glass plate having a thickness of, for example, about 3 mm. The optical filter 26 is elastically supported by a rubber packing 34 while being supported by a support portion 24d formed in the housing portion 24b. By doing so, it is possible to prevent the optical filter 26 from being damaged by an external impact or the like applied to the detection device S.
[0031]
The photosensor 27 detects the intensity of the ultraviolet light that has passed through the optical filter 26, and can accurately measure the range from the ultraviolet region to the visible region, and is a plate-shaped silicon photodiode (for example, having a reduced infrared sensitivity). And Hamamatsu Photonics S1227-1BR). The light receiving surface (the right side surface in FIG. 3) of the photo sensor 27 faces the light source 29, and the light receiving surface is bonded and fixed to the optical filter 26.
[0032]
The light from the light source 29 may be reflected by the light transmitting cylindrical member 10 and the reflected light may be reflected by the optical filter 26. Therefore, the photo sensor 27 is provided separately from the optical filter 26. Then, the reflected light from the optical filter 26 may be incident on the photo sensor 27, and the intensity of the ultraviolet light may not be accurately detected. On the other hand, in the present embodiment, the above fear is prevented by bonding the photosensor 27 to the optical filter 26.
[0033]
Since the output characteristics of the ultraviolet light from the light source 29 change due to the temperature change near the light source 29, the intensity of the ultraviolet light from the light source 29 is measured by the photo sensor 27, and the detection values of the photo sensors 20 and 28 described later are corrected. I do it. Specifically, the correction is made by dividing the detection values of the photo sensors 20 and 28 by the detection values of the photo sensor 27.
[0034]
A light-shielding support plate 33 made of a material having light-shielding properties and rigidity (eg, iron) is arranged between the housing 24 and the seal member 31. The housing 24 and the light-shielding support plate 33, and the light-shielding support plate 33 and the seal member 31 are bonded to each other. A light-transmitting window 330 for irradiating the light from the light source 29 to the first light-transmitting portion 10A of the light-transmitting cylindrical member 10 is formed in the light-shielding support plate 33. The light transmitted through the first light transmitting portion 10A enters the light transmitting cylindrical member 10. The first light transmitting portion 10A is a portion of the light transmitting cylindrical member 10 where light from the light source 29 is incident.
[0035]
The housing 17 is formed with an accommodation portion 17a for accommodating an optical filter (filter member) 19, a photosensor (fluorescence amount detecting means) 20, and a rubber insulating seal member 21 in a stacked manner.
A metal (for example, aluminum) that covers a frame-shaped support portion 17b formed on the inner wall of the light-transmitting cylindrical member 10 side portion of the housing portion 17a and a portion of the housing portion 17a opposite to the light-transmitting cylindrical member 10 The optical filter 19, the photo sensor 20, and the insulating seal member 21 are sequentially arranged and supported between the holding plate 22 and the holding plate 22. The holding plate 22 is attached to the long and thick plate-shaped housing 17 with bolts 23.
[0036]
Then, the fluorescence emitted by the lubricating oil receiving the light incident from the first light transmitting portion 10A is incident on the optical filter 19 and the photo sensor 20 via the second light transmitting portion 10B of the light transmitting cylindrical member 10. The second light-transmitting portion 10B is a portion of the light-transmitting cylindrical member 10 that emits light incident on a rectangular opening 17c formed inside the support portion 17b. The opposing site and its vicinity.
[0037]
The optical filter 19 mainly transmits light of a predetermined wavelength (for example, 480 to 600 nm) of the light from the light-transmitting cylindrical member 10, and has a maximum transmittance wavelength of 530 nm and a maximum transmittance of 42%. And a band-pass filter having a half-value width of 48 nm (for example, BPN-53 manufactured by Fuji Photo Film Co., Ltd.). The optical filter 19 is a plate-like filter having a thickness of, for example, about 0.2 mm and containing triacetate as a main component. The light receiving surface (the lower surface in FIG. 3) of the optical filter 19 is opposed to the second light transmitting portion 10B of the light transmitting cylindrical member 10. Here, the light receiving surface of the optical filter 19, that is, the perpendicular line T of the light receiving surface (the lower surface in FIG. 3) of the photosensor 20 and the traveling path D of the light source 29 formed by the ultraviolet passage forming portion 24c form an acute angle. , The light source 29, the optical filter 19, and the photosensor 20 are arranged. As a result, it is possible to satisfactorily suppress the light from the light source 29 from being directly incident on the photosensor 20, and prevent the photosensor 20 from detecting the light from the light source 29.
[0038]
The optical filter 19 that mainly transmits light having a wavelength of 480 to 600 nm suppresses the light transmitted through the optical filter 26 that mainly transmits light having a wavelength of 280 to 400 nm from entering the photosensor 20. it can. Therefore, the light transmitted through the optical filter 26 and the fluorescent light from the lubricating oil described later can be satisfactorily separated. Therefore, the detection accuracy of the photo sensor 20 is good. The photosensor 20 is for detecting the fluorescence intensity A of the fluorescence that has passed through the optical filter 19, and is capable of accurately measuring from the ultraviolet region to the visible region, and having a suppressed infrared sensitivity. For example, it is made of S1227-1010BR manufactured by Hamamatsu Photonics.
[0039]
In the housing 25, a housing part 25a for housing a photosensor (transmitted light amount detecting means) 28 is formed at a position symmetrical with respect to the light source 29 about the light transmitting cylindrical member 10. Between the housing 25 and the packing 32, a light-shielding support plate 35 made of a material (for example, iron) having light-shielding properties and rigidity and supporting the photosensor 28 is arranged. An opening 350 that allows light to enter the photosensor 28 is formed in the light-shielding support plate 35, and an edge of the opening 350 supports an outer peripheral portion of the photosensor 28. The housing 25 and the light-shielding support plate 35, and the light-shielding support plate 35 and the packing 32 are bonded to each other.
[0040]
The photosensor 28 detects the transmitted light intensity B of the light (transmitted light) from the light-transmitting cylindrical member 10 and includes a silicon photodiode similar to the photosensor 20 described above. Then, of the light incident from the first light transmitting portion 10A, light transmitted through the inside of the light transmitting cylindrical member 10 (that is, light not absorbed and scattered by the liquid refrigerant and the lubricating oil) is converted into the third light transmitting portion 10C. , And is incident on the photosensor 28 (that is, inside the opening 35 of the light shielding support plate 35).
[0041]
Each of the photosensors 20, 27, and 28 has a pair of lead terminals (not shown). By connecting the lead terminals to an amplifier (not shown), the light reception voltages of the photosensors 20, 27, and 28 are detected. ing. Further, the light-transmitting cylindrical member 10 constitutes the first, second, and third light-transmitting portions described in claims, and also constitutes a compressor suction-side refrigerant pipe.
[0042]
Here, the fluorescence intensity A of the fluorescence emitted from the second translucent portion 10B and the flow rate Q of the lubricating oil flowing through the translucent cylindrical member 10 (that is, the flow rate of the fluorescent material contained in the lubricating oil) are shown in FIG. The relationship is as shown in the graph of FIG. That is, the lubricating oil flowing through the translucent cylindrical member 10 scatters fluorescence (having a main emission wavelength of 500 to 580 nm) with a fluorescence intensity A proportional to the flow rate Q due to the incident ultraviolet light. Incident. Then, the photo sensor 20 generates a light receiving voltage V by receiving the fluorescence having the fluorescence intensity A.
[0043]
Further, the transmitted light intensity B of the transmitted light emitted from the third light transmitting portion 10C and the flow rate R of the liquid refrigerant flowing through the light transmitting cylindrical member 10 have a relationship as shown in the graph of FIG. That is, since the amount of scattering of the incident ultraviolet light in the light-transmitting cylindrical member 10 changes in accordance with the flow rate R of the liquid refrigerant flowing in the light-transmitting cylindrical member 10, the incident ultraviolet light incident on the light-transmitting cylindrical member 10 Light (transmitted light) transmitted through the light transmitting cylindrical member 10 and emitted from the light transmitting cylindrical member 10 toward the photosensor 28 enters the photosensor 28 with a transmitted light intensity B corresponding to the flow rate R of the liquid refrigerant. The photosensor 28 generates a light receiving voltage E by receiving the transmitted light having the transmitted light intensity B. Since the amount of ultraviolet light absorbed by the lubricating oil is very small compared to the amount of ultraviolet light scattered by the liquid refrigerant, the flow rate R of the liquid refrigerant is determined by the transmitted light intensity B of the transmitted light emitted from the third light transmitting portion 10C. Can be detected.
[0044]
Then, the electric control device (see FIG. 1) 110 mounted on the vehicle reads the received light voltages V and E generated by the photosensors 20 and 28, and calculates by the calculating means 110a based on the read information. Then, based on the calculation result, the drive control means 110b controls the drive of the connection state of the electromagnetic clutch 1a (that is, the stop of the operation of the compressor 1).
[0045]
Hereinafter, the operation of the arithmetic unit 110a and the drive control unit 110b will be described in detail.
First, a predetermined voltage V ₀ and a predetermined voltage ratio H ₀ are stored in the ROM of the electric control device 110 in advance. The predetermined voltage V ₀ corresponds to a predetermined fluorescent intensity A ₀ , and the predetermined fluorescent intensity A ₀ is a predetermined flow rate Q ₀ (for example, 1 kg / h) which is an upper limit of a lubricating oil flow rate that causes insufficient lubrication of the compressor 1. ). The predetermined voltage ratio H ₀ corresponds to a predetermined light intensity ratio, and the predetermined light intensity ratio is a ratio of the flow rate ratio between the lubricating oil and the liquid refrigerant (lubricating oil flow rate / liquid refrigerant flow rate) which causes insufficient lubrication of the compressor 1. It corresponds to a predetermined flow rate ratio (for example, 1/10) which is an upper limit value.
[0046]
The calculation means 110a calculates the voltage ratio (receiving voltage V / receiving voltage E) H between the light receiving voltage V receiving voltage E, as well as comparing the voltage ratio H and the predetermined voltage ratio H _0, light It compares the voltage V and the predetermined voltage V _0. The calculating means 110a constitutes a flow ratio calculating means for calculating the above-mentioned voltage ratio H to calculate a flow ratio between the lubricating oil and the liquid refrigerant (lubricating oil flow rate / liquid refrigerant flow rate).
[0047]
Then, the calculating means 110a determines that V> V ₀ (that is, the flow rate Q of the lubricating oil is larger than the predetermined flow rate Q ₀ ) and that H> H ₀ (that is, the flow rate ratio of the lubricating oil to the liquid refrigerant). Is greater than the predetermined flow rate ratio), it is determined that the compressor 1 is well lubricated, and the drive control unit 110b sets the electromagnetic clutch 1a of the compressor 1 to the connected state. To generate a connection signal. Thereby, the electromagnetic clutch 1a is brought into the connected state, and the compressor 1 operates.
[0048]
Further, the arithmetic means 110a determines that V ≦ V ₀ (that is, the flow rate Q of the lubricating oil is equal to or less than the predetermined flow rate Q ₀ ) and H ≦ H ₀ (that is, the flow rate ratio of the lubricating oil to the liquid refrigerant is Is determined to be less than the predetermined flow rate ratio), it is determined that the compressor 1 has insufficient lubricity, and in response to this determination, the drive control unit 110b switches the electromagnetic clutch 1a of the compressor 1 A non-connection signal for making a non-connection state is generated. As a result, the electromagnetic clutch 1a is disconnected, and the compressor 1 stops.
[0049]
Then, based on the received light voltage V of the photo sensor 20 corresponding to the flow rate of the lubricating oil flowing through the refrigerant pipe P5, the lack of lubricity in the compressor 1 can be accurately determined. Can reliably be prevented.
Further, by detecting the light receiving voltage E of the photo sensor 28 corresponding to the flow rate of the liquid refrigerant flowing through the refrigerant pipe P5 in addition to the light receiving voltage V of the photo sensor 20, it is possible to more accurately determine the lack of lubricity of the compressor. In addition, the failure of the compressor 1 can be more reliably prevented.
[0050]
The arithmetic means 110a constitutes a judging means for judging that the compressor 1 has insufficient lubricity when any one of V ≦ V ₀ and H ≦ H ₀ . Further, the drive control means 110b constitutes a compressor stop means for stopping the compressor 1 when the arithmetic means 110a determines that the lubricity of the compressor 1 is insufficient.
(Other embodiments)
First, on the surface of the light transmitting cylindrical member 10 and the inner wall surface of the cover member 100, in order to suppress the light from the light source 29 from being reflected and incident on the photosensors 20, 27, and 28, the light transmitting cylindrical member An anti-reflection layer may be formed on the surface of the cover 10 and the inner wall surface of the cover member 100. Specifically, a black light-absorbing layer may be formed on the surface of the light-transmitting cylindrical member 10 or the inner wall surface of the cover member 100, or may be formed on the surface of the light-transmitting cylindrical member 10 or the inner wall surface of the cover member 100. Alternatively, a light diffusion layer that diffusely reflects light may be formed.
[0051]
Further, in the above-described embodiment, the compressor 1 is stopped due to the decrease in the flow rate Q of the lubricating oil or the decrease in the flow rate ratio. However, other various controls may be performed. For example, the amount of air blown to the evaporator 5 may be increased to promote heat exchange, and the amount of refrigerant evaporated in the evaporator 5 may be increased. May be reduced to completely evaporate the refrigerant, or the expansion valve opening may be increased to increase the lubricating oil flow rate.
[0052]
Further, the flow rate R of the liquid refrigerant is large, focusing on the suction operation of the compressor 1 is not carried out satisfactorily, by comparing the received voltage E and the predetermined voltage E _0, the deactivation of the compressor 1 It may be controlled. The predetermined voltage E ₀ corresponds to a predetermined intensity of transmitted light B _0, the predetermined transmitted light intensity B ₀ is suction operation of the compressor 1 is flow-rate upper limit of the liquid refrigerant such that not performed satisfactorily predetermined It corresponds to the flow rate R ₀ (for example, 10 kg / h).
[0053]
In the above embodiment, the transmitted light intensity B of the transmitted light emitted from the third light transmitting unit 10C is detected in accordance with the flow rate of the liquid refrigerant. However, the transmitted light intensity B is emitted from the third light transmitting unit 10C. The transmitted light intensity B of the transmitted light is detected in accordance with the flow rates of the liquid refrigerant and the lubricating oil, and the lubrication of the compressor 1 is determined using the detected value and the flow rate of the lubricating oil detected by the fluorescent intensity A. It may be controlled to maintain good properties.
[0054]
Further, the flow rate detection device S of the present invention may be applied to an experimental refrigeration cycle arranged in a laboratory.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram and an electric block diagram of a refrigeration cycle of the present invention.
FIG. 2 is a cross-sectional view of the flow rate detection device according to the first embodiment of the present invention.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
FIG. 4 is a diagram illustrating an arrangement relationship of components of the flow rate detection device according to the first embodiment.
FIG. 5 is a graph showing a relationship between a flow rate of a lubricating oil and a fluorescence intensity.
FIG. 6 is a graph showing a relationship between a flow rate of a liquid refrigerant and a transmitted light intensity.
FIG. 7 is a cross-sectional view of a flow rate detection device according to the related art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Condenser, 4 ... Expansion valve, 5 ... Evaporator,
P5: refrigerant pipe (compressor suction side refrigerant pipe), 10: translucent cylindrical member,
10A, 10B, 10C: first, second, and third light transmitting portions; 29, light source;
20 ... photo sensor (fluorescence amount detecting means),
28 Photosensor (transmitted light amount detecting means).

Claims

Of the refrigerating cycle in which the compressor (1), the condenser (2), the expansion valve (4), and the evaporator (5) are sequentially connected by refrigerant pipes (P1 to P5, 10), the evaporator (5) A flow rate detection device for a refrigeration cycle provided in a compressor suction side refrigerant pipe (P5, 10) between the compressor and the compressor (1),
A light source (29);
A first light-transmitting portion (10A) that is provided airtightly in the compressor suction-side refrigerant pipe (P5, 10) and allows light from the light source (29) to enter the compressor suction-side refrigerant pipe (P5, 10). )When,
The lubricating oil which is provided in the compressor suction side refrigerant pipes (P5, 10) in an airtight manner and which flows inside the compressor suction side refrigerant pipes (P5, 10) is incident on the first light transmitting portion (10A). A second light-transmitting portion (10B) for emitting fluorescence emitted upon receiving the light to the outside of the compressor suction-side refrigerant pipe (P5, 10);
A flow rate detecting device for a refrigeration cycle, comprising: a fluorescent light amount detecting means (20) for detecting a flow amount of the lubricating oil as a light amount of fluorescent light emitted from the second light transmitting portion (10B).

The compressor suction-side refrigerant pipes (P5, 10) are airtightly provided in the compressor suction-side refrigerant pipes (P5, 10), and transmitted through the compressor suction-side refrigerant pipes (P5, 10) of the light incident from the first light transmitting portion (10A). A third light-transmitting portion (10C) for emitting light to the outside of the compressor suction-side refrigerant pipe (P5, 10);
2. The refrigeration cycle according to claim 1, further comprising: a transmitted light amount detection unit configured to detect a flow rate of the liquid refrigerant as an amount of transmitted light emitted from the third light transmitting unit. Flow detector.

The light source comprises one light source (29);
The light from the one light source (29) is caused to enter from the first light transmitting portion (10A) and is emitted from the second light transmitting portion (10B) and the third light transmitting portion (10C). The flow rate detection device for a refrigeration cycle according to claim 2.

The light source (29) and the light source (29) are arranged so that the traveling path (D) of the light from the light source (29) and the perpendicular (T) of the light receiving surface of the fluorescence amount detection means (20) are arranged at an acute angle. The flow rate detecting device for a refrigeration cycle according to any one of claims 1 to 3, wherein the fluorescence amount detecting means (20) is arranged.

The filter member (19) that mainly transmits the fluorescence is provided between the fluorescence amount detection means (20) and the second light transmitting portion (10B). The flow rate detection device for a refrigeration cycle according to any one of the above.

A flow ratio between the lubricating oil and the liquid refrigerant is calculated based on the amount of fluorescence detected by the amount of fluorescence detecting means (20) and the amount of transmitted light detected by the amount of transmitted light detecting means (28). The flow rate detecting device for a refrigeration cycle according to any one of claims 2 to 5, further comprising a flow rate ratio calculating means (110a).

A flow rate detection device for a refrigeration cycle according to claim 6,
When the detected value of the fluorescence amount detecting means (20) is equal to or less than a predetermined value and / or when the calculated value of the flow rate ratio calculating means (110a) is equal to or less than a predetermined value, the compressor Determining means (110a) for determining that (1) is insufficient in lubricity;
A compressor stopping means (110b) for stopping the compressor (1) when the judging means (110a) judges insufficient lubricity of the compressor (1). Refrigeration cycle control device.