JP3779772B2

JP3779772B2 - Engine supercharging device and control method thereof

Info

Publication number: JP3779772B2
Application number: JP18051296A
Authority: JP
Inventors: 博内田; 雄二岩切; 昭信別所; 実石野
Original assignee: Toyota Central R&D Labs Inc
Current assignee: Toyota Central R&D Labs Inc
Priority date: 1996-07-10
Filing date: 1996-07-10
Publication date: 2006-05-31
Anticipated expiration: 2016-07-10
Also published as: JPH1026027A

Description

【０００１】
【発明の属する技術分野】
本発明は、エンジンのシリンダに遠心圧縮機で高圧空気を供給する過給装置とその制御方法に関する。
【０００２】
【従来の技術】
ターボチャージャとも呼ばれる排気タービン過給装置は、エンジンのシリンダに接続した吸気通路の途中に遠心圧縮機を介在し、エンジンのシリンダに接続した排気通路の途中にガスタービンを介在し、遠心圧縮機とガスタービンを同軸に連結している。
【０００３】
排気通路を流れる排気ガスでガスタービンが回転されて遠心圧縮機が回転され、吸気通路を流れる空気が遠心圧縮機で圧縮され、高圧になった空気がエンジンのシリンダに供給される。
【０００４】
エンジンは、その外周の大気圧より高圧の空気が供給されることにより、出力特性が向上する。
【０００５】
【発明が解決しようとする課題】
ところが、エンジンの過給装置は、エンジンの低速域では、遠心圧縮機のサージング限界のため、遠心圧縮機の圧力比を十分に高めることができず、十分に過給することができない。従って、エンジンの低速域では、過給による加速性能の向上や排気エミッションの低減を達成することが困難である。
【０００６】
また、自動車用エンジンのように運転範囲が広いエンジンの過給装置においては、遠心圧縮機は、運転範囲が広く、最高効率点をはずれた条件でも運転され、小流量域では、効率が高くない。従って、エンジンの低速域では、過給効率が高いとは言い難い。
【０００７】
【課題を解決するための着眼】
エンジンの過給装置において、遠心圧縮機は、空気入口から回転中の羽根車に流入する空気流に羽根車と同一方向の旋回を与えると、小流量域で現れるサージング限界が更に小流量側に移動し、小流量域でも、圧力比を高めることができ、また、最高効率点が小流量側に移動し、小流量域でも、効率を高めることができることを発見した。
【０００８】
そこで、遠心圧縮機は、図２に示すように、羽根車と同芯状の空気入口に、回転中の羽根車１２に流入する空気流に旋回を与える案内羽根２３を、羽根車１２の軸芯方向からの傾斜角度を調整可能に設け、空気流量が少なくなるエンジンの低速域では、案内羽根２３の傾斜角度を大きくして、回転中の羽根車１２に流入する空気流に羽根車１２と同一方向の大きな旋回を与え、空気流量が多くなるエンジンの高速域では、案内羽根２３の傾斜角度を小さくし、または、零にして、回転中の羽根車１２に流入する空気流に羽根車１２と同一方向の小さな旋回を与え、または、旋回を与えないことを考え付いた。
【０００９】
【課題を解決するための手段】
本発明は、自動車用エンジンのシリンダに接続した吸気通路の途中に遠心圧縮機を介在し、自動車用エンジンのシリンダに接続した排気通路の途中にガスタービンを介在し、排気通路を流れる排気ガスで回転するガスタービンと、吸気通路を流れる空気を圧縮する遠心圧縮機を連結し、自動車用エンジンのシリンダに高圧空気を供給する遠心圧縮機に、回転中の羽根車に流入する空気流に羽根車と同一方向の旋回を与える空気流旋回機構を旋回量調整可能に設けたエンジンの過給装置において、
自動車用エンジンの低速域では、遠心圧縮機は、羽根車に流入する空気流に与える旋回を大きくし、小流量域で現れるサージング限界を更に小流量側に移動し、また、最高効率点を小流量側に移動し、
自動車用エンジンの高速域では、遠心圧縮機は、羽根車に流入する空気流に与える旋回を小さくまたは零にし、最高効率点を大流量側に戻し、また、空気流に旋回を与えることによる圧力損失を少なくすることを特徴とする制御方法である。
【００１１】
【発明の効果】
エンジンの低速域でも、遠心圧縮機の圧力比を高めて、過給による加速性能の向上や排気エミッションの低減を達成することができ、また、遠心圧縮機の効率を高めることができる。
【００１２】
【発明の実施の形態】
＜第１例（図１〜図５参照）＞
本例のエンジンの過給装置は、図１に略示するように、自動車用エンジンの排気タービン過給装置であり、自動車用エンジンの複数のシリンダ１の吸気口に接続した吸気通路２の途中に遠心圧縮機３を介在し、複数のシリンダ１の排気口に接続した排気通路４の途中にガスタービン５を介在し、遠心圧縮機３とガスタービン５を同軸に連結している。
【００１３】
エンジンの排気通路４を流れる排気ガスでガスタービン５が回転されて遠心圧縮機３が回転され、吸気通路２を流れる空気が遠心圧縮機３で圧縮され、高圧になった空気が各シリンダ１に供給される。
【００１４】
遠心圧縮機３は、図２に示すように、ケーシング１１の中央部に羽根車１２を入れ、羽根車１２の軸１３をケーシング１１の後部に軸受し、ケーシング１１の前部に円筒形状の空気入口管１４を羽根車１２と同芯状に設け、ケーシング１１の外周部にディフューザ１５と渦巻室１６を内外に同芯状に設けている。渦巻室１６の大径部には、図示しないが、空気出口管を接続している。
【００１５】
羽根車１２は、図３に示すように、円盤形状の主板１７の中心部に軸１３を貫通して固定し、主板１７の前面に湾曲板形状の羽根１８を等間隔位置にほぼ径方向に沿って固定している。
【００１６】
エンジンの吸気通路２を流れる空気は、遠心圧縮機３の空気入口管１４から回転中の羽根車１２の前面の入口に流入し、羽根車１２の羽根１８の間の湾曲通路を通って、羽根車１２の外周の出口からディフューザ１５を経て渦巻室１６に流入し、高圧になった空気が渦巻室１６の空気出口管から流出し、エンジンのシリンダ１に流入する。
【００１７】
遠心圧縮機３は、図２に示すように、羽根車１２と同芯状の空気入口に、回転中の羽根車１２に流入する空気流に羽根車１２と同一方向の旋回を与える空気流旋回機構２１を旋回量調整可能に設けている。
【００１８】
空気流旋回機構２１は、図２に示すように、円筒形状の空気入口管１４の中心を挟む上下の２個所に、それぞれ、軸２２を空気入口管１４の径方向に貫通して軸受し、空気入口管１４内に突出した両軸２２の内側部の後側に、それぞれ、その軸２２の軸芯方向に沿って略三角板形状の案内羽根２３の前側を固定し、空気入口管１４の中心に近付くに従って空気入口管１４の軸芯方向の幅が狭くなる両案内羽根２３を、それぞれ、羽根車１２の前面の入口の前側に配置している。
【００１９】
空気入口管１４外に突出した両軸２２の外端には、図２に示すように、それぞれ、その軸２２を所望の角度回転する回転駆動装置２４を連結し、上下の両案内羽根２３を、それぞれ、その案内羽根２３と対面した羽根車１２の羽根１８の移動方向に傾斜可能にし、図４に示すように、両案内羽根２３がそれぞれ空気入口管１４と羽根車１２の軸芯方向から傾斜する角度を調整可能にしている。回転駆動装置２４には、ステップモータ式、油圧または空圧式のアクチュエータが例示される。
【００２０】
両案内羽根２３が羽根車１２の軸芯方向に配置されて羽根車１２の軸芯方向から傾斜していないと、両案内羽根２３のない従来の場合と同様に、空気入口管１４の空気流が羽根車１２の軸芯方向に流れて羽根車１２の入口に流入する。
【００２１】
両案内羽根２３がそれぞれその案内羽根２３と対面した羽根車１２の羽根１８の移動方向に傾斜していると、各案内羽根２３を通過する空気流がそれぞれその案内羽根２３でその傾斜方向に折曲されて羽根車１２の軸芯方向から傾斜し、回転中の羽根車１２の入口に流入する空気流が羽根車１２と同一方向に同芯状に旋回する。
【００２２】
羽根車１２の入口の速度三角形は、両案内羽根２３が羽根車１２の軸芯方向から傾斜せず、空気入口管１４を流れる空気流が羽根車１２の軸芯方向から羽根車１２の入口に流入するときには、図４に破線で示すようになり、両案内羽根２３が羽根車１２の軸芯方向から傾斜して、羽根車１２の入口に流入する空気流が羽根車の羽根１８の移動方向に傾斜するときには、図４に実線で示すようになる。
【００２３】
図４中、Ｃは、空気入口管１４を流れる空気流の絶対速度を示し、Ｕは、羽根車１２の入口の周方向速度を示し、Ｗは、空気流が羽根車１２の入口に流入する相対速度を示す。αは、羽根車１２の入口に流入する空気流が羽根車１２の軸芯方向から羽根車の羽根１８の移動方向に傾斜する角度を示し、βは、空気流が羽根車１２の入口に流入する相対角度を示す。
【００２４】
羽根車１２の入口の速度三角形から明らかなように、両案内羽根２３が羽根車１２の軸芯方向から傾斜して、羽根車１２の入口に流入する空気流が羽根車の羽根１８の移動方向に傾斜して羽根車１２と同一方向に旋回すると、空気流が羽根車１２の入口に流入する相対角度βがほとんど変化せずに、空気入口管１４を流れる空気流の軸芯方向の絶対速度Ｃcosαと、空気流が羽根車１２の入口に流入する相対速度Ｗが減少する。
【００２５】
羽根車１２に流入する空気流が傾斜する角度αが大きくなるに従って、空気流が羽根車１２に流入する相対角度βがほとんど変化せずに、空気流の軸芯方向の絶対速度Ｃcosαと空気流の相対流入速度Ｗ、即ち、羽根車１２に流入する空気流量が徐々に減少する。遠心圧縮機３は、空気流が羽根車１２に流入する相対角度βが羽根車の羽根１８の入口角度に一致して空気流が羽根車の羽根１８に沿って流れるときに効率が最高になり、また、空気流が羽根車の羽根１８から激しく剥離して不安定になるとサージングになるので、空気流の傾斜角度αが大きくなるに従って、最高効率点が小流量側に移動し、また、サージング限界が小流量側に移動する。
【００２６】
遠心圧縮機３の空気流量に対する効率と圧力比の特性は、回転速度がｎ₁とｎ₂（ｎ₁＜ｎ₂）である場合、空気流の傾斜角度αが小さいまたは零のときには、図５に細線で示すようになり、空気流の傾斜角度αが大きいときには、図５に実線で示すようになる。
【００２７】
図５から明らかなように、空気流の傾斜角度αが大きくなると、効率の最高点が小流量側に移動し、また、小流量域でサージング線が小流量側に移動してエンジン作動線が小流量側に移動する。
【００２８】
回転速度が遅くてｎ₁である場合、空気流の傾斜角度αが小さいまたは零のときには、遠心圧縮機３が有効に作動する最小の空気流量がＱ₂であるが、空気流の傾斜角度αが大きくなると、圧力比と効率がほとんど変化せずに、最小の空気流量が更に小さくなってＱ₁になる。空気流量がＱ₂より少ない領域でも、遠心圧縮機３が有効に作動する。即ち、エンジンの更に低速の領域でも、遠心圧縮機３の圧力比を高めて、過給による加速性能の向上や排気エミッションの低減を達成することができる。
【００２９】
また、回転速度がｎ₁より速くてｎ₂であり、空気流量が中流量域のＱ₃である場合、空気流の傾斜角度αが小さいまたは零のときには、効率がη₁であるが、空気流の傾斜角度αが大きくなると、圧力比が変化せずに、効率が高くなって η₂になる。
【００３０】
図２に示すように、両案内羽根２３の回転駆動装置２４をエンジンの回転速度に応じて制御する制御装置２５を設けている。エンジンの低速域では、両案内羽根２３の傾斜角度を大きくして、羽根車１２に流入する空気流に与える旋回を大きくし、エンジンの高速域では、両案内羽根２３の傾斜角度を小さくまたは零にして、羽根車１２に流入する空気流に与える旋回を小さくまたは零にする。
【００３１】
＜第２例（図６と図７参照）＞
本例のエンジンの過給装置は、第１例における遠心圧縮機の空気流旋回機構２１の案内羽根の回転駆動装置２４とその制御装置２５を簡単な構造にしたものである。
【００３２】
案内羽根２３の傾斜角度をエンジンの回転速度に応じて制御する制御装置３１は、図６と図７に示すように、両案内羽根２３の軸２２の外端に、それぞれ、その径方向に突出した腕３２を固定し、各腕３２の先端とケーシング１１の外面の間に螺旋ばね３３を取り付けて、各軸２２に、それぞれ、その軸２２の後側の案内羽根２３を羽根車１２の軸芯方向から羽根車の羽根１８の移動方向に傾斜させる弾性回転力を付与し、ケーシング１１の外面に、各腕３２に当たるストップピン３４を固定して、各案内羽根２３の傾斜角度が許容角度を越えない構成にしている。
【００３３】
エンジンの低速域では、遠心圧縮機の羽根車１２に流入する空気流の流量が少なく、空気流が螺旋ばね３３による弾性回転力に抗して各案内羽根２３を回転させる力が弱く、両案内羽根２３が羽根車の羽根１８の移動方向に傾斜する角度が大きくなって、羽根車１２に流入する空気流に与えられる旋回が大きくなる。
【００３４】
エンジンの高速域では、遠心圧縮機の羽根車１２に流入する空気流の流量が多く、空気流が螺旋ばね３３による弾性回転力に抗して各案内羽根２３を回転させる力が強く、図６と図７に示すように、両案内羽根２３が羽根車の羽根１８の移動方向に傾斜する角度が小さくまたは零になって、羽根車１２に流入する空気流に与えられる旋回が小さくまたは零になる。
【００３５】
その他の点は、第１例におけるのと同様である。
【００３６】
＜第３例（図８参照）＞
本例のエンジンの過給装置は、第１例における遠心圧縮機の空気流旋回機構２１の案内羽根２３の形状を変えて枚数を増やし、全案内羽根を連動して傾斜させる機構を設けたものである。
【００３７】
空気流旋回機構４１は、図８に示すように、円筒形状の空気入口管１４の中心を挟む上下と左右の４個所に、それぞれ、軸４２を空気入口管１４の径方向に貫通して軸受し、空気入口管１４内に突出した各軸４２の内側部の後側と前側に、それぞれ、その軸の軸芯方向に沿って三角板形状の案内羽根４３を固定し、空気入口管１４の中心に近付くに従って空気入口管１４の軸芯方向の幅が狭くなる各案内羽根４３を、それぞれ、羽根車１２の前面の入口の前側に配置している。
【００３８】
全案内羽根４３を連動して傾斜させる機構は、図８に示すように、空気入口管１４外に突出した各軸４２の外端にそれぞれピニオン４４を固定し、ケーシング１１の外周段部に軸受４５を介して円環形状のフェースギヤ４６を嵌合し、フェースギヤ４６に各ピニオン４４を噛み合わせている。いずれかのピニオン４４またはフェースギヤ４６を回転すると、４枚のピニオン４４が同様に回転して、４枚の案内羽根４３が連動して傾斜する。
【００３９】
１本の軸４２には、図８に示すように、その軸４２を所望の角度回転する回転駆動装置２４を連結し、回転駆動装置２４をエンジンの回転速度に応じて制御する制御装置２５を設けている。エンジンの低速域では、全案内羽根４３の傾斜角度を大きくして、羽根車１２に流入する空気流に与える旋回を大きくし、エンジンの高速域では、全案内羽根４３の傾斜角度を小さくまたは零にして、羽根車１２に流入する空気流に与える旋回を小さくまたは零にする。
【００４０】
その他の点は、第１例におけるのと同様である。
【００４１】
回転駆動装置２４は、軸４２に代えてフェースギヤ４６に連結してもよい。ピニオン４４とフェースギヤ４６は、ベベルギヤにしてもよい。
【００４２】
全案内羽根を連動して傾斜させる機構４４，４５，４６は、第１例または第２例における空気流旋回機構２１に設けて、回転駆動装置２４または弾性回転力付与機構３２，３３，３４を１個にしてもよい。
【図面の簡単な説明】
【図１】本発明の実施形態の第１例のエンジンの過給装置の概略図。
【図２】同過給装置の遠心圧縮機の縦断面図であって案内羽根が傾斜していない状態の図。
【図３】同過給装置の遠心圧縮機の羽根車の斜視図。
【図４】図２のＡ−Ａ線断面図であって案内羽根が傾斜している状態の図。
【図５】同過給装置の遠心圧縮機の空気流量に対する効率と圧力比の特性線図。
【図６】第２例の過給装置の遠心圧縮機の縦断面図であって案内羽根が傾斜していない状態の図。
【図７】図６のＢ−Ｂ線断面図。
【図８】第３例の過給装置の遠心圧縮機の縦断面図であって案内羽根が傾斜していない状態の図。
【符号の説明】
１エンジンのシリンダ
３過給装置の遠心圧縮機
１２羽根車
２１，４１空気流旋回機構
２２，４２軸
２３，４３案内羽根
２４回転駆動装置
２５制御装置
３２腕，弾性回転力付与機構
３３螺旋ばね，弾性回転力付与機構
４４ピニオン，全案内羽根を連動して傾斜させる機構
４６フェースギヤ，全案内羽根を連動して傾斜させる機構[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a supercharging device that supplies high-pressure air to a cylinder of an engine with a centrifugal compressor, and a control method thereof .
[0002]
[Prior art]
An exhaust turbine supercharging device, also called a turbocharger, has a centrifugal compressor in the middle of an intake passage connected to an engine cylinder, and a gas turbine in the middle of an exhaust passage connected to an engine cylinder. The gas turbine is connected coaxially.
[0003]
The gas turbine is rotated by the exhaust gas flowing through the exhaust passage to rotate the centrifugal compressor, the air flowing through the intake passage is compressed by the centrifugal compressor, and the high-pressure air is supplied to the engine cylinder.
[0004]
The engine is improved in output characteristics by being supplied with air whose pressure is higher than the atmospheric pressure on the outer periphery thereof.
[0005]
[Problems to be solved by the invention]
However, the engine supercharging device cannot sufficiently increase the pressure ratio of the centrifugal compressor due to the surging limit of the centrifugal compressor at a low speed region of the engine, and cannot sufficiently supercharge. Therefore, it is difficult to improve acceleration performance and reduce exhaust emission by supercharging at low engine speeds.
[0006]
In addition, in a turbocharger of an engine having a wide operating range such as an automobile engine, the centrifugal compressor is operated even under a condition where the operating range is outside the maximum efficiency point, and the efficiency is not high in a small flow rate range. . Therefore, it is difficult to say that the supercharging efficiency is high in the low speed region of the engine.
[0007]
[Focus to solve problems]
In an engine supercharger, when the centrifugal compressor gives a swirl in the same direction as the impeller to the air flow flowing into the rotating impeller from the air inlet, the surging limit that appears in the small flow rate region is further reduced to the small flow rate side. It has been found that the pressure ratio can be increased even in a small flow rate region, and that the highest efficiency point can be moved to the small flow rate side, and the efficiency can be increased even in the small flow rate region.
[0008]
Therefore, as shown in FIG. 2, the centrifugal compressor has guide vanes 23 that turn the air flow flowing into the rotating impeller 12 at the air inlet concentric with the impeller 12. The inclination angle from the core direction can be adjusted, and in the low speed region of the engine where the air flow rate is reduced, the inclination angle of the guide vane 23 is increased so that the air flow flowing into the rotating impeller 12 In the high speed region of the engine in which a large turn in the same direction is given and the air flow rate is increased, the inclination angle of the guide vane 23 is reduced or zero, and the impeller 12 is added to the air flow flowing into the rotating impeller 12. I thought of giving a small turn in the same direction or not giving a turn.
[0009]
[Means for Solving the Problems]
The present invention provides an exhaust gas that flows through an exhaust passage by interposing a centrifugal compressor in the middle of an intake passage connected to a cylinder of an automobile engine, and a gas turbine in the middle of an exhaust passage connected to a cylinder of the automobile engine. The rotating gas turbine and the centrifugal compressor that compresses the air flowing through the intake passage are connected to the centrifugal compressor that supplies high-pressure air to the cylinder of the automobile engine. In the engine supercharging device provided with an air flow swirl mechanism that can swivel in the same direction as the swivel amount can be adjusted,
In the low speed range of an automotive engine, the centrifugal compressor increases the swirl applied to the airflow flowing into the impeller, moves the surging limit that appears in the small flow rate range to the low flow rate side, and reduces the maximum efficiency point. Move to the flow side,
At high speeds in automotive engines, centrifugal compressors reduce or reduce the swirl applied to the airflow entering the impeller, return the highest efficiency point to the higher flow rate side, and the pressure resulting from swirling the airflow. This is a control method characterized by reducing loss .
[0011]
【The invention's effect】
Even in the low speed region of the engine, the pressure ratio of the centrifugal compressor can be increased to improve the acceleration performance by supercharging and reduce the exhaust emission, and the efficiency of the centrifugal compressor can be increased.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
<First example (see FIGS. 1 to 5)>
The engine supercharging device of this example is an exhaust turbine supercharging device for an automobile engine, as schematically shown in FIG. 1, and is in the middle of an intake passage 2 connected to intake ports of a plurality of cylinders 1 of the automobile engine. The centrifugal compressor 3 is interposed, the gas turbine 5 is interposed in the middle of the exhaust passage 4 connected to the exhaust ports of the cylinders 1, and the centrifugal compressor 3 and the gas turbine 5 are connected coaxially.
[0013]
The gas turbine 5 is rotated by the exhaust gas flowing through the exhaust passage 4 of the engine to rotate the centrifugal compressor 3, the air flowing through the intake passage 2 is compressed by the centrifugal compressor 3, and the high pressure air is applied to each cylinder 1. Supplied.
[0014]
As shown in FIG. 2, the centrifugal compressor 3 includes an impeller 12 at the center of the casing 11, a shaft 13 of the impeller 12 is supported at the rear of the casing 11, and a cylindrical air is formed at the front of the casing 11. An inlet pipe 14 is provided concentrically with the impeller 12, and a diffuser 15 and a spiral chamber 16 are provided concentrically on the inside and outside of the casing 11. Although not shown, an air outlet pipe is connected to the large diameter portion of the spiral chamber 16.
[0015]
As shown in FIG. 3, the impeller 12 is fixed to the center portion of the disk-shaped main plate 17 through the shaft 13, and the curved plate-shaped blades 18 are arranged on the front surface of the main plate 17 at substantially equal positions in the radial direction. It is fixed along.
[0016]
Air flowing in the intake passage 2 of the engine flows from the air inlet pipe 14 of the centrifugal compressor 3 into the front inlet of the rotating impeller 12, passes through the curved passage between the blades 18 of the impeller 12, From the outlet on the outer periphery of the vehicle 12, the air flows into the spiral chamber 16 through the diffuser 15, and the high-pressure air flows out from the air outlet pipe of the spiral chamber 16 and flows into the cylinder 1 of the engine.
[0017]
As shown in FIG. 2, the centrifugal compressor 3 has an air flow swirl that imparts a swirl in the same direction as the impeller 12 to an air flow that flows into the rotating impeller 12 at an air inlet concentric with the impeller 12. The mechanism 21 is provided so that the turning amount can be adjusted.
[0018]
As shown in FIG. 2, the air flow swirl mechanism 21 has shafts 22 penetrating and bearing in the radial direction of the air inlet tube 14 at two locations above and below the center of the cylindrical air inlet tube 14, respectively. The front side of a substantially triangular plate-shaped guide vane 23 is fixed to the rear side of the inner part of both shafts 22 projecting into the air inlet tube 14 along the axial direction of the shaft 22, and the center of the air inlet tube 14 is fixed. Both guide vanes 23 whose width in the axial center direction of the air inlet pipe 14 becomes narrower as the distance from the front is closer to the front side of the front entrance of the impeller 12.
[0019]
As shown in FIG. 2, a rotary drive device 24 that rotates the shaft 22 by a desired angle is connected to the outer ends of both shafts 22 protruding out of the air inlet pipe 14, and the upper and lower guide vanes 23 are connected to each other. Each of the guide vanes 23 can be inclined from the axial direction of the air inlet pipe 14 and the impeller 12 as shown in FIG. The inclination angle can be adjusted. The rotary drive device 24 is exemplified by a step motor type, hydraulic type or pneumatic type actuator.
[0020]
If both guide vanes 23 are arranged in the axial direction of the impeller 12 and are not inclined from the axial direction of the impeller 12, the air flow in the air inlet pipe 14 is the same as in the conventional case without the both guide vanes 23. Flows in the axial direction of the impeller 12 and flows into the inlet of the impeller 12.
[0021]
When both guide blades 23 are inclined in the moving direction of the blades 18 of the impeller 12 facing the guide blades 23, the air flow passing through each guide blade 23 is folded in the inclined direction by the guide blades 23. The airflow which is bent and inclined from the axial direction of the impeller 12 and flows into the inlet of the rotating impeller 12 turns concentrically in the same direction as the impeller 12.
[0022]
The speed triangle at the inlet of the impeller 12 is such that both guide blades 23 are not inclined from the axial direction of the impeller 12, and the air flow flowing through the air inlet pipe 14 flows from the axial direction of the impeller 12 to the inlet of the impeller 12. When the air flows in, it becomes as shown by a broken line in FIG. 4, both guide blades 23 are inclined from the axial direction of the impeller 12, and the air flow flowing into the inlet of the impeller 12 is the moving direction of the impeller blades 18 As shown in FIG.
[0023]
In FIG. 4, C represents the absolute velocity of the airflow flowing through the air inlet pipe 14, U represents the circumferential velocity at the inlet of the impeller 12, and W represents the airflow flowing into the inlet of the impeller 12. Indicates relative speed. α indicates the angle at which the airflow flowing into the inlet of the impeller 12 is inclined from the axial direction of the impeller 12 in the moving direction of the blade 18 of the impeller 12, and β is the airflow flowing into the inlet of the impeller 12 Indicates the relative angle to perform.
[0024]
As is apparent from the velocity triangle at the inlet of the impeller 12, both guide vanes 23 are inclined from the axial center direction of the impeller 12, and the air flow flowing into the inlet of the impeller 12 is the moving direction of the impeller blades 18. Is inclined in the same direction as the impeller 12, the relative angle β at which the airflow flows into the inlet of the impeller 12 hardly changes, and the absolute velocity in the axial direction of the airflow flowing through the air inlet pipe 14 is almost unchanged. Ccosα and the relative speed W at which the airflow flows into the inlet of the impeller 12 are reduced.
[0025]
As the angle α at which the airflow flowing into the impeller 12 tilts increases, the relative angle β at which the airflow flows into the impeller 12 hardly changes, and the absolute velocity Ccosα in the axial direction of the airflow and the airflow Relative inflow speed W, that is, the flow rate of air flowing into the impeller 12 gradually decreases. Centrifugal compressor 3 has the highest efficiency when the airflow flows along the impeller blades 18 with the relative angle β at which the airflow flows into the impeller 12 matches the inlet angle of the impeller blades 18. In addition, surging occurs when the air flow is severely separated from the impeller blades 18 and becomes unstable. Therefore, the maximum efficiency point moves to the smaller flow rate side as the air flow inclination angle α increases, and surging occurs. The limit moves to the small flow rate side.
[0026]
The characteristics of the efficiency and pressure ratio with respect to the air flow rate of the centrifugal compressor 3 are as shown in FIG. 5 when the rotational speed is n ₁ and n ₂ (n ₁ <n ₂ ), and the air flow inclination angle α is small or zero. When the inclination angle α of the air flow is large, it is as shown by a solid line in FIG.
[0027]
As is clear from FIG. 5, when the air flow inclination angle α increases, the highest efficiency point moves to the small flow rate side, and the surging line moves to the small flow rate side in the small flow rate region so that the engine operating line becomes smaller. Move to the small flow rate side.
[0028]
When the rotational speed is slow and n ₁ , when the air flow inclination angle α is small or zero, the minimum air flow rate at which the centrifugal compressor 3 operates effectively is Q ₂ , but the air flow inclination angle α If larger, with little change in pressure ratio and efficiency, minimum air flow rate is Q ₁ is further reduced. Even in the region where the air flow rate is less than Q ₂ , the centrifugal compressor 3 operates effectively. That is, even in a lower speed region of the engine, the pressure ratio of the centrifugal compressor 3 can be increased to improve acceleration performance and reduce exhaust emissions by supercharging.
[0029]
Further, when the rotational speed is higher than n ₁ and n ₂ and the air flow rate is Q ₃ in the middle flow rate region, the efficiency is η ₁ when the air flow inclination angle α is small or zero, As the flow inclination angle α increases, the pressure ratio does not change and the efficiency increases to η ₂ .
[0030]
As shown in FIG. 2, a control device 25 is provided for controlling the rotational drive device 24 of both guide vanes 23 in accordance with the rotational speed of the engine. In the low speed region of the engine, the inclination angle of both guide vanes 23 is increased to increase the swirl applied to the airflow flowing into the impeller 12, and in the high speed region of the engine, the inclination angle of both guide vanes 23 is decreased to zero or zero. Thus, the turning applied to the air flow flowing into the impeller 12 is reduced or made zero.
[0031]
<Second example (see FIGS. 6 and 7)>
The supercharging device for the engine of this example is a simple construction of the guide blade rotation drive device 24 and its control device 25 of the centrifugal compressor air flow swirl mechanism 21 of the first example.
[0032]
As shown in FIGS. 6 and 7, the control device 31 that controls the inclination angle of the guide blades 23 in accordance with the rotational speed of the engine protrudes in the radial direction at the outer ends of the shafts 22 of both guide blades 23. The arm 32 is fixed, a spiral spring 33 is attached between the tip of each arm 32 and the outer surface of the casing 11, and the guide vane 23 on the rear side of the shaft 22 is attached to each shaft 22. An elastic rotational force that inclines in the moving direction of the impeller blades 18 from the core direction is applied, a stop pin 34 that contacts each arm 32 is fixed to the outer surface of the casing 11, and the inclination angle of each guide blade 23 has an allowable angle. The structure does not exceed.
[0033]
In the low speed region of the engine, the flow rate of the air flow flowing into the impeller 12 of the centrifugal compressor is small, and the force of the air flow rotating the guide blades 23 against the elastic rotational force by the helical spring 33 is weak. The angle at which the blade 23 inclines in the moving direction of the blade 18 of the impeller increases, and the swirl imparted to the air flow flowing into the impeller 12 increases.
[0034]
In the high speed region of the engine, the flow rate of the air flow flowing into the impeller 12 of the centrifugal compressor is large, and the force of the air flow rotating the guide blades 23 against the elastic rotational force by the helical spring 33 is strong. As shown in FIG. 7, the angle at which both guide vanes 23 are inclined in the moving direction of the impeller blades 18 is small or zero, and the swirl applied to the airflow flowing into the impeller 12 is small or zero. Become.
[0035]
Other points are the same as in the first example.
[0036]
<Third example (see FIG. 8)>
The engine supercharging device of this example is provided with a mechanism for changing the shape of the guide vanes 23 of the air flow swirl mechanism 21 of the centrifugal compressor in the first example to increase the number of guide vanes and inclining all the guide vanes in conjunction with each other. It is.
[0037]
As shown in FIG. 8, the air flow swirl mechanism 41 is provided with bearings by penetrating shafts 42 in the radial direction of the air inlet pipe 14 at four locations on the upper and lower sides and the left and right sides of the center of the cylindrical air inlet pipe 14. The triangular blade-shaped guide vanes 43 are fixed to the rear side and the front side of the inner portion of each shaft 42 protruding into the air inlet tube 14 along the axial direction of the shaft, respectively. The guide vanes 43 whose width in the axial center direction of the air inlet pipe 14 becomes narrower as the distance from the front is closer to the front side of the inlet of the front surface of the impeller 12.
[0038]
As shown in FIG. 8, the mechanism for inclining all the guide vanes 43 is configured such that pinions 44 are fixed to the outer ends of the respective shafts 42 protruding out of the air inlet pipe 14, and bearings are provided on the outer peripheral step portion of the casing 11. An annular face gear 46 is fitted through 45, and each pinion 44 is engaged with the face gear 46. When any one of the pinions 44 or the face gear 46 is rotated, the four pinions 44 are similarly rotated, and the four guide blades 43 are inclined in conjunction with each other.
[0039]
As shown in FIG. 8, a rotation drive device 24 that rotates the shaft 42 at a desired angle is connected to one shaft 42, and a control device 25 that controls the rotation drive device 24 according to the rotational speed of the engine. Provided. In the low speed region of the engine, the inclination angle of all the guide blades 43 is increased to increase the swirl applied to the air flow flowing into the impeller 12, and in the high speed region of the engine, the inclination angle of all the guide blades 43 is decreased to zero or zero. Thus, the turning applied to the airflow flowing into the impeller 12 is reduced or made zero.
[0040]
Other points are the same as in the first example.
[0041]
The rotation driving device 24 may be connected to the face gear 46 instead of the shaft 42. The pinion 44 and the face gear 46 may be bevel gears.
[0042]
The mechanisms 44, 45, and 46 for inclining all the guide blades in conjunction with each other are provided in the air flow swirl mechanism 21 in the first example or the second example, and the rotation driving device 24 or the elastic torque application mechanism 32, 33, 34 is provided. It may be one.
[Brief description of the drawings]
FIG. 1 is a schematic view of a supercharging device for an engine according to a first example of an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a centrifugal compressor of the supercharging device, in a state where guide blades are not inclined.
FIG. 3 is a perspective view of an impeller of a centrifugal compressor of the supercharging device.
4 is a cross-sectional view taken along the line AA in FIG. 2 and shows a state in which the guide vanes are inclined. FIG.
FIG. 5 is a characteristic diagram of efficiency and pressure ratio with respect to the air flow rate of the centrifugal compressor of the supercharging device.
FIG. 6 is a longitudinal sectional view of a centrifugal compressor of the supercharging device of the second example, in a state where the guide vanes are not inclined.
7 is a sectional view taken along line BB in FIG.
FIG. 8 is a longitudinal sectional view of a centrifugal compressor of a supercharging device according to a third example, in which the guide vanes are not inclined.
[Explanation of symbols]
1 Engine Cylinder 3 Turbocharger Centrifugal Compressor 12 Impeller 21, 41 Air Flow Swivel Mechanism 22, 42 Shaft 23, 43 Guide Blade 24 Rotation Drive Device 25 Control Device 32 Arm, Elastic Rotation Force Application Mechanism 33 Spiral Spring, Elastic rotational force imparting mechanism 44 Mechanism for inclining the pinion and all guide vanes in conjunction 46 Mechanism for inclining the face gear and all guide vanes in conjunction

Claims

A gas turbine rotating with exhaust gas flowing through the exhaust passage with a centrifugal compressor interposed in the middle of the intake passage connected to the cylinder of the automobile engine and a gas turbine interposed in the middle of the exhaust passage connected to the cylinder of the automobile engine And a centrifugal compressor that compresses the air flowing in the intake passage, and supplies the high-pressure air to the cylinder of the automobile engine, and the air flow flowing into the rotating impeller is in the same direction as the impeller. In an engine supercharging device provided with an air flow swirl mechanism for swirling so as to be capable of adjusting a swirl amount,
In the low speed range of an automotive engine, the centrifugal compressor increases the swirl applied to the airflow flowing into the impeller, moves the surging limit that appears in the small flow rate range to the low flow rate side, and reduces the maximum efficiency point. Move to the flow side,
At high speeds in automotive engines, centrifugal compressors reduce or reduce the swirl applied to the airflow entering the impeller, return the highest efficiency point to the higher flow rate side, and the pressure resulting from swirling the airflow. A control method characterized by reducing loss.

An engine supercharging device that implements the control method according to claim 1,
The air flow swirling mechanism has shafts bearing in the radial direction of the impeller at a plurality of positions sandwiching the center of the air inlet concentric with the impeller, respectively, fixing the guide vanes to each shaft, Each guide vane is arranged in front of the impeller inlet and gives the airflow flowing into the rotating impeller in the same direction as the impeller so that the inclination angle from the axial direction of the impeller can be adjusted. An engine supercharging device characterized by that.

3. A control device for connecting a rotation driving device that rotates the shaft to a desired angle to the shaft of the guide vane and controlling the rotation driving device in accordance with the rotational speed of an automobile engine. The engine supercharger described.

An elastic rotational force is applied to the shaft of the guide blade to incline the guide blade of the shaft from the axial direction of the impeller, and the airflow flowing into the impeller against the elastic rotational force is the flow rate of the guide blade. In the low speed range of the automotive engine, the angle at which the guide vane tilts from the axial direction of the impeller is increased. In the high speed range of the automotive engine, the guide vane tilts from the axial direction of the impeller. The engine supercharging device according to claim 2, wherein an angle of the engine is set to be small or zero.

5. A supercharging device for an engine according to claim 2, wherein a mechanism for tilting all guide blades in an interlocking manner is provided.