JP4108842B2

JP4108842B2 - Air cleaner

Info

Publication number: JP4108842B2
Application number: JP28158198A
Authority: JP
Inventors: 陽一大西; 政道赤川
Original assignee: Denso Corp; Toyota Motor Corp
Current assignee: Denso Corp; Toyota Motor Corp
Priority date: 1998-10-02
Filing date: 1998-10-02
Publication date: 2008-06-25
Anticipated expiration: 2018-10-02
Also published as: JP2000110676A

Description

【０００１】
【発明の属する技術分野】
本発明は、湾曲部を有するとともに、その湾曲部よりも上流側に流量計を有する流体配管を備え、特に内燃機関に用いるのに適したエアクリーナに関する。
【０００２】
【従来の技術】
特開平５−２５６２１６号公報は、内燃機関のエアクリーナに対する空気流量計の取付構造を開示している。図５に示すように、同公報のエアクリーナ１０１はクリーナエレメント１０２を内蔵している。エアクリーナ１０１には、外気導入ダクト１０３が接続されるとともに、空気排出口としての筒状部材１０４が一体形成されている。筒状部材１０４には、内燃機関のシリンダ（図示せず）に繋がる吸気管１０５が接続されている。空気流量計１０６は筒状部材１０４に挿入された状態で取り付けられている。流量計１０６はその先端に、筒状部材１０４を通過する空気の流量を測定するためのセンサエレメント１０６ａを備える。
【０００３】
ところで、内燃機関及びそれに付随するエアクリーナ等の各種機器を狭いエンジンルーム内に可能な限りコンパクトに且つ整然と収めるために、従来より様々な手段が講じられている。例えば、図５に示すエアクリーナ１０１において、搭載スペースの制約上、空気流量計１０６の下流側に充分な長さの直線流路を確保することができないことがある。そのような場合には、図５に２点鎖線で示すように、筒状部材１０４或いは吸気管１０５を空気流量計１０６の下流側において湾曲させる必要が生じる。
【０００４】
【発明が解決しようとする課題】
しかしながら、発明者は、流量計１０６の下流側に湾曲流路を設けると、流量計１０６から出力される検出信号が大きく変動して流量の正確な計測が行い得なくなることを、実験により確認した。しかも、発明者は、流量計１０６からの検出信号の変動が、内燃機関の常用回転数である２０００〜３０００ｒｐｍの範囲で顕著に現れることも、実験により確認している。
【０００５】
空気が湾曲部を流れるとき、曲率半径の大きい湾曲部の外周側を流れる空気の方が、曲率半径の小さい湾曲部の内周側を流れる空気よりも、その流速が速くなる。湾曲部で流速の差が生じると、湾曲部の上流側に位置する流量計１０６の付近においても、湾曲部と同様な流速の差が生じる。しかも、内燃機関のピストンによる吸気動作等に起因して、吸気管１０５及び筒状部材１０４内には脈動が生じる。そして、上記した流速の差や脈動等の複数の要因が絡み合った結果、流量計１０６の付近の空気の流れが乱れて、流量計１０６からの検出信号が変動するものと考えられる。
【０００６】
流量計１０６と湾曲部との間に充分な長さの直線流路を確保することができれば、湾曲部での流速の差の影響が流量計１０６の付近にまで及ばず、流量計１０６からの検出信号の変動を許容範囲内に収めることができる。しかしながら、流量計１０６と湾曲部との間に充分な長さの直線流路を確保することができない場合には、流量計１０６からの検出信号の変動を許容範囲内に収めることができず、流量の正確な計測を行うことができない。
【０００７】
本発明は上記問題点を解消するためになされたものであり、その目的は、湾曲部を有するとともに、その湾曲部よりも上流側に流量計を備えた流体配管において、内部を通過する流体の流量を正確に計測することを可能にするエアクリーナを提供することにある。
【０００９】
【課題を解決するための手段】
（１）請求項１に記載の発明は、空気導入口と空気排出口との間にクリーナエレメントが設けられるとともに空気排出口に流体配管の入口が接続されたエアクリーナであって、この流体配管として、流体を導入するための入口とこの入口の下流側に設けられた湾曲部とを有するとともに、これら入口と湾曲部との間に内部を通過する流体の流量を計測するための流量計を有するものが接続されたエアクリーナにおいて、前記流体配管の入口の開口縁は、流量計の測定点を含み且つ流体配管の軸線と直交する面内においての流体の速度をほぼ均一にすべく、前記流体配管の入口から湾曲部に向かう流体の流れを整流するための整流手段として、流体配管の軸線と直交する面に対して傾斜する態様で構成されるものであり、この傾斜により当該開口縁のうちの前記湾曲部の内周側に対応する部分が当該開口縁のうちの前記湾曲部の外周側に対応する部分よりも流体配管の軸線方向に突出するものであることを要旨としている。
【００１０】
（２）請求項２に記載の発明は、空気導入口と空気排出口との間にクリーナエレメントが設けられるとともに空気排出口に流体配管の入口が接続されたエアクリーナであって、この流体配管として、流体を導入するための入口とこの入口の下流側に設けられた湾曲部とを有するとともに、これら入口と湾曲部との間に内部を通過する流体の流量を計測するための流量計を有するものが接続されたエアクリーナにおいて、前記流体配管の入口の開口縁は、流量計の測定点を含み且つ流体配管の軸線と直交する面内においての流体の速度をほぼ均一にすべく、前記流体配管の入口から湾曲部に向かう流体の流れを整流するための整流手段として構成されるものであり、当該開口縁のうちの前記湾曲部の内周側に対応する部分からこの湾曲部の内周側の端までの距離が当該開口縁のうちの前記湾曲部の外周側に対応する部分からこの湾曲部の外周側の端までの距離よりも大きく設定されるものであることを要旨としている。
【００１１】
流体配管の入口に設けられた整流手段は、流量計の測定点を含み且つ流体配管の軸線と直交する面内における流体の速度がほぼ均一となるように、入口から湾曲部に向かう流体の流れを整流する。つまり、湾曲部の外周側と内周側とで流体の流速に差が生じることを見越して、その流速の差の影響が及ぶ流量計の付近においては流速の差が生じないように、流体配管の入口部分において流体の流れが整流手段により予め調整される。そのため、流量計の付近の流体の流れが乱れることが抑制される。
すなわち、湾曲部の内周側に対応する開口縁の部分から導入された流体は、湾曲部の外周側に対応する開口縁の部分から導入された流体よりも、長い距離を経て流量計に到る。この長い距離の分は、流体配管に導入された流体のための助走区間となる。従って、湾曲部の内周側に対応する開口縁の部分から導入された流体の方が、湾曲部の外周側に対応する開口縁の部分から導入された流体よりも、流量計に到るまでに流速が速くなる傾向にある。一方、湾曲部においては、その内周側を流れる流体の流速よりも外周側を流れる流体の流速の方が速くなる傾向にある。そのため、流体配管の入口と湾曲部との間に設けられた流量計の付近においては、湾曲部の外周側に対応する部分を流れる流体の流速と、湾曲部の内周側に対応する部分を流れる流体の流速とがほぼ同じになる。
【００１２】
（３）請求項３に記載の発明は、空気導入口と空気排出口との間にクリーナエレメントが設けられるとともに空気排出口に流体配管の入口が接続されたエアクリーナであって、この流体配管として、流体を導入するための入口とこの入口の下流側に設けられた湾曲部とを有するとともに、これら入口と湾曲部との間に内部を通過する流体の流量を計測するための流量計を有するものが接続されたエアクリーナにおいて、前記流体配管の入口には、流量計の測定点を含み且つ流体配管の軸線と直交する面内においての流体の速度をほぼ均一にすべく、前記流体配管の入口から湾曲部に向かう流体の流れを整流するための整流手段として機能する整流格子が設けられ、この整流格子は、前記湾曲部の外周側に対応する部分においての流体の流通抵抗が前記湾曲部の内周側に対応する部分においての流体の流通抵抗よりも大きくなる態様で形成されることを要旨としている。
【００１３】
（４）請求項４に記載の発明は、空気導入口と空気排出口との間にクリーナエレメントが設けられるとともに空気排出口に流体配管の入口が接続されたエアクリーナであって、この流体配管として、流体を導入するための入口とこの入口の下流側に設けられた湾曲部とを有するとともに、これら入口と湾曲部との間に内部を通過する流体の流量を計測するための流量計を有するものが接続されたエアクリーナにおいて、前記流体配管の入口には、流量計の測定点を含み且つ流体配管の軸線と直交する面内においての流体の速度をほぼ均一にすべく、前記流体配管の入口から湾曲部に向かう流体の流れを整流するための整流手段として機能する整流格子が設けられ、この整流格子は、前記湾曲部の内周側に対応する部分から前記湾曲部の外周側に対応する部分に向けて格子の目が細かくなる態様で形成されることを要旨としている。
【００１４】
流体配管の入口に設けられた整流手段は、流量計の測定点を含み且つ流体配管の軸線と直交する面内における流体の速度がほぼ均一となるように、入口から湾曲部に向かう流体の流れを整流する。つまり、湾曲部の外周側と内周側とで流体の流速に差が生じることを見越して、その流速の差の影響が及ぶ流量計の付近においては流速の差が生じないように、流体配管の入口部分において流体の流れが整流手段により予め調整される。そのため、流量計の付近の流体の流れが乱れることが抑制される。
すなわち、湾曲部の外周側に対応する整流格子の部分を通過する流体の流速が、湾曲部の内周側に対応する整流格子の部分を通過する流体の流速と比較して抑制される。一方、湾曲部においては、その内周側を流れる流体の流速よりも外周側を流れる流体の流速の方が速くなる傾向にある。そのため、流体配管の入口と湾曲部との間に設けられた流量計の付近においては、湾曲部の外周側に対応する部分を流れる流体の流速と、湾曲部の内周側に対応する部分を流れる流体の流速とがほぼ同じになる。
【００１６】
【発明の実施の形態】
以下、本発明を内燃機関に用いられるエアクリーナに具体化した第１実施形態について、図１に従って説明する。
【００１７】
図１に示すように、エアクリーナ１は、上面に開口部を有する下部ボディ２と、その下部ボディ２の開口部を覆うように下部ボディ２上に着脱可能に固定された上部ボディ３とを備える。上部ボディ３は図示しないクランプにより下部ボディ２上に固定される。クリーナエレメント４は、例えば下部ボディ２の開口部に装着されている。下部ボディ２はその下面に空気導入口５を有する。上部ボディ３は空気排出口６を有し、その空気排出口６には流体配管としての吸気管７の入口８が接続されている。特に図示しないが、吸気管７は自動車のエンジンルームに搭載された内燃機関のシリンダに接続される。
【００１８】
吸気管７の入口８は上部ボディ３内に開口する。吸気管７はまた、入口８の下流側に湾曲部９を有する。空気流量計１０は、入口８と湾曲部９との間において、吸気管７に取り付けられている。流量計１０は、その先端に設けられたセンサエレメント１１が吸気管７内に配置されるように、吸気管７に挿入されている。流量計１０はその先端に、吸気管７の軸線Ｌと平行な軸線を有する円筒部を備えており、その円筒部内にセンサエレメント１１が配置されている。センサエレメント１１は、空気流量を測定するための測定点に位置する。
【００１９】
内燃機関の運転時には、空気導入口５からエアクリーナ１内に導入された空気が、クリーナエレメント４を通過することによって清浄にされた後に、吸気管７の入口８に導入される。そして、空気は入口８から湾曲部９を経て内燃機関のシリンダに供給される。流量計１０のセンサエレメント１１は、円筒部を通過する空気の流量に応じた検出信号を出力する。特に図示しないが、センサエレメント１１からの検出信号は、配線を通じてエンジンコントロールユニットに送られる。
【００２０】
吸気管７の入口８は、整流手段として機能する開口縁８ａを有する。その開口縁８ａは、吸気管７の軸線Ｌと直交する面Ｐ１に対して所定の角度θを以て傾斜している。この傾斜により、湾曲部９の内周側に対応する開口縁８ａの部分が、湾曲部９の外周側に対応する開口縁８ａの部分よりも、吸気管７の軸線Ｌ方向に突出している。言い換えれば、湾曲部９の端から同湾曲部９の内周側に対応する開口縁８ａの部分までの距離Ｄ１が、湾曲部９の端から同湾曲部９の外周側に対応する開口縁８ａの部分までの距離Ｄ２よりも大きくなっている。
【００２１】
次に、上記のように構成されたエアクリーナ１の作用について説明する。
従来技術の欄でも説明したように、吸気管７の入口８から導入された空気が湾曲部９を通過するとき、曲率半径の大きい湾曲部９の外周側を流れる空気の方が、曲率半径の小さい湾曲部９の内周側を流れる空気よりも、その流速が速くなる。湾曲部９での流速の差は、湾曲部９の上流側に位置する流量計１０の付近の空気の流れにも影響を及ぼす。
【００２２】
しかしながら、本実施形態では、入口８の開口縁８ａの傾斜により、湾曲部９の内周側に対応する開口縁８ａの部分から導入された空気は、湾曲部９の外周側に対応する開口縁８ａの部分から導入された空気よりも、長い距離を経て流量計１０に到る。この長い距離の分（図１にＳで示す斜線の範囲に相当）は、吸気管７に導入された空気のための助走区間となる。従って、湾曲部９の内周側に対応する開口縁８ａの部分から導入された空気の方が、湾曲部９の外周側に対応する開口縁８ａの部分から導入された空気よりも、流量計１０に到るまでに流速が速くなる傾向にある。一方、前述のように、湾曲部９においては、その内周側を流れる空気の流速よりも外周側を流れる空気の流速の方が速くなる傾向にある。そのため、吸気管７の入口８と湾曲部９との間に設けられた流量計１０の付近においては、湾曲部９の外周側に対応する部分を流れる空気の流速と、湾曲部９の内周側に対応する部分を流れる空気の流速とがほぼ同じになる。
【００２３】
このように、湾曲部９の外周側と内周側とで空気の流速に差が生じることを見越して、その流速の差の影響が及ぶ流量計１０の付近においては流速の差が生じないように、斜状の入口８の部分において空気の流れが予め調整される。言い換えれば、流量計１０の測定点を含み且つ吸気管７の軸線Ｌと直交する面Ｐ２内における空気の流速がほぼ均一となるように、入口８から湾曲部９に向かう空気の流れが整流される。
【００２４】
・従って、本実施形態では、流量計１０の付近の空気流の乱れ及びその乱れに起因する流量計１０からの検出信号の変動を抑制することができる。発明者の実験によると、本実施形態の吸気管７を採用することによって、流量計１０からの検出信号の変動が許容範囲内に収まり、流量の正確な計測が可能になることが確認されている。空気流量を正確に計測することができれば、その計測結果に基づき内燃機関を良好に制御できる。
【００２５】
・しかも、入口８の開口縁８ａを斜状に形成するだけの簡単な構成で上記効果を達成できるので、製造に要する手間が少なくて済むとともに、製造コストを軽減できる。
【００２６】
次に、本発明の第２実施形態について、上記第１実施形態との相違点を中心に図２及び図３に従って説明する。
図２及び図３に示すように、本実施形態では、入口８の開口縁８ａを斜状に形成することに代えて、整流手段として機能する整流格子２０が入口８に設けられている。なお、整流格子２０は、吸気管７に別体物として取り付けられても良く、或いは吸気管７と一体に形成されても良い。
【００２７】
整流格子２０は、湾曲部９の内周側に対応する部分から湾曲部９の外周側に対応する部分に向かうに従って、空気の通過を許容する格子の目が徐々に細かくなるように形成されている。従って、湾曲部９の内周側に対応する整流格子２０の部分から湾曲部９の外周側に対応する整流格子２０の部分に向かうに従って、空気の通過抵抗が大きくなる。
【００２８】
このため、湾曲部９の外周側に対応する整流格子２０の部分を通過する空気の流速が、湾曲部９の内周側に対応する整流格子２０の部分を通過する空気の流速と比較して抑制される。一方、湾曲部９においては、その内周側を流れる空気の流速よりも外周側を流れる空気の流速の方が速くなる傾向にある。そのため、吸気管７の入口８と湾曲部９との間に設けられた流量計１０の付近においては、湾曲部９の外周側に対応する部分を流れる空気の流速と、湾曲部９の内周側に対応する部分を流れる空気の流速とがほぼ同じになる。言い換えれば、流量計１０の測定点を含み且つ吸気管７の軸線Ｌと直交する面Ｐ２内における空気の流速がほぼ均一となるように、入口８から湾曲部９に向かう空気の流れが整流格子２０によって整流される。
【００２９】
・従って、本実施形態においても、上記第１実施形態と同様に、流量計１０の付近の空気流の乱れ及びその乱れに起因する流量計１０からの検出信号の変動を抑制することができる。
【００３０】
・しかも、整流格子２０の目の大きさを調整することによって、吸気管７の入口８から導入される空気の流れをきめ細かく調整することができる。
図４は、整流格子の他の実施形態を示す。同図に示すように、本実施形態の整流格子２１は、湾曲部９の内周側に対応する第１の格子部２１ａと、湾曲部９の外周側に対応する第２の格子部２１ｂとを有する。第２の格子部２１ｂにおける格子の目は、第１の格子部２１ａにおける格子の目よりも細かい。従って、第２の格子部２１ｂの方が第１の格子部２１ａよりも、空気の通過抵抗が大きくなる。そのため、湾曲部９の外周側に対応する第２の格子部２１ｂを通過する空気の流速が、湾曲部９の内周側に対応する第１の格子部２１ａを通過する空気の流速と比較して抑制される。
【００３１】
・従って、本実施形態においても、上記第２実施形態とほぼ同様の作用効果が得られる。
・特に、本実施形態の整流格子２１では、格子の目の大きさが２段階に形成されているので、格子の目の大きさが連続的に変化する第２実施形態の整流格子２０よりも製造が容易である。
【００３２】
なお、本発明の実施形態は上記の各実施形態に限定されるものではなく、次のような変更例も可能である。
・図１の実施形態或いは図３及び図４の各実施形態において、開口縁８ａの傾斜角θや各整流格子２１，２０の目の大きさは、吸気管７の径、湾曲部９の曲率や曲げ角、流量計１０から入口８までの距離、或いは流量計１０から湾曲部９までの距離等の各種条件に応じて、適宜設定されればよい。すなわち、流量計１０の測定点を含み且つ吸気管７の軸線Ｌと直交する面Ｐ２内における空気の流速がほぼ均一となるように空気の流れを整流することができるのであれば、開口縁８ａの傾斜角θや各整流格子２１，２０の目の大きさとしてどのような値が採用されてもよい。
【００３３】
・図１の実施形態では、開口縁８ａが、吸気管７の軸線Ｌと直交する面Ｐ１に対して傾斜する一平面上に設けられる。しかしながら、図１に２点鎖線で示すように、開口縁８ａは、吸気管７の軸線Ｌと直交する面Ｐ１に対して傾斜する平面に対して膨らんだ形状或いは凹んだ形状を成していてもよい。
【００３４】
・図３及び図４の実施形態において、各整流格子２１，２０の目は四角形状に限らず、円形状或いは三角形状等、どのような形状をなしていてもよい。
・流量計１０としては、流体の流量を計測するためのものであれば、いかなるタイプのものが適用されてもよい。
【００３５】
・上記各実施形態では、本発明を、内燃機関におけるエアクリーナの吸気管において具体化した。しかしながら、本発明は、エアクリーナの吸気管に限らず、湾曲部を有するとともにその湾曲部よりも上流側に流量計を備えた流体配管であれば、いかなる流体配管においても適用可能である。
【００３６】
以下に、特許請求の範囲に記載された技術的思想の他に、上記の各実施形態から把握できる技術的思想を記載する。
（１）前記開口縁は、流体配管の軸線と直交する面に対して傾斜する一平面上に設けられている請求項１または２に記載の流体配管。このようにすれば、製造が容易になる。
【００３７】
（２）前記整流格子は、湾曲部の内周側に対応する部分から湾曲部の外周側に対応する部分に向かうに従って、流体の通過を許容する格子の目が徐々に細かくなるように形成されている請求項３または４に記載の流体配管。このようにすれば、入口から導入される流体の流れをきめ細かく調整することができる。
【００３８】
（３）前記整流格子は、湾曲部の内周側に対応する第１の格子部と、湾曲部の外周側に対応する第２の格子部とを有し、第２の格子部における格子の目は第１の格子部における格子の目よりも細かくなっている請求項３または４に記載の流体配管。このようにすれば、格子の目の大きさを２段階に形成するだけでよいので、製造が容易である。
【００３９】
【発明の効果】
以上詳述したように、本発明によれば、整流手段によって流体の流れを整流することにより、湾曲した流体配管を通過する流体の流量を、流量計によって正確に計測することができる。
【００４０】
入口の開口縁を傾斜させることによって整流手段を構成した場合には、製造に要する手間が少なくて済むとともに、製造コストを軽減できる。
整流手段として整流格子を適用した場合には、入口から導入される空気の流れをきめ細かく調整することができる。
【００４１】
また、内燃機関のエアクリーナとして具体化した場合には、吸気管を通過する空気の流量を正確に計測することができる。
【図面の簡単な説明】
【図１】本発明の第１実施形態を示すエアクリーナの断面図。
【図２】本発明の第２実施形態を示すエアクリーナの部分断面図。
【図３】図２の整流格子を正面から見た図。
【図４】他の実施形態における整流格子を正面から見た図。
【図５】従来技術におけるエアクリーナを示す断面図。
【符号の説明】
１…エアクリーナ、４…クリーナエレメント、５…空気導入口、６…空気排出口、７…流体配管としての吸気管、８…入口、８ａ…開口縁、９…湾曲部、１０…空気流量計、２０…整流手段としての整流格子、２１…整流手段としての整流格子。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air cleaner that has a curved portion and includes a fluid pipe having a flow meter upstream of the curved portion, and is particularly suitable for use in an internal combustion engine.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 5-256216 discloses an air flow meter mounting structure for an air cleaner of an internal combustion engine. As shown in FIG. 5, the air cleaner 101 of the same publication incorporates a cleaner element 102. An external air introduction duct 103 is connected to the air cleaner 101, and a cylindrical member 104 as an air discharge port is integrally formed. An intake pipe 105 connected to a cylinder (not shown) of the internal combustion engine is connected to the cylindrical member 104. The air flow meter 106 is attached while being inserted into the cylindrical member 104. The flow meter 106 includes a sensor element 106 a for measuring the flow rate of air passing through the tubular member 104 at the tip thereof.
[0003]
By the way, various means have been taken conventionally in order to house various devices such as an internal combustion engine and an air cleaner associated therewith in a narrow engine room as compactly and orderly as possible. For example, in the air cleaner 101 shown in FIG. 5, there may be a case where a sufficiently long straight flow path cannot be secured on the downstream side of the air flow meter 106 due to restrictions on the mounting space. In such a case, it is necessary to curve the tubular member 104 or the intake pipe 105 on the downstream side of the air flow meter 106 as shown by a two-dot chain line in FIG.
[0004]
[Problems to be solved by the invention]
However, the inventor has confirmed through experiments that if a curved flow path is provided on the downstream side of the flow meter 106, the detection signal output from the flow meter 106 will fluctuate so that accurate measurement of the flow rate cannot be performed. . In addition, the inventor has also confirmed through experiments that fluctuations in the detection signal from the flowmeter 106 appear significantly in the range of 2000 to 3000 rpm, which is the normal rotational speed of the internal combustion engine.
[0005]
When air flows through the curved portion, the flow velocity of air flowing on the outer peripheral side of the curved portion having a large curvature radius is faster than that flowing on the inner peripheral side of the curved portion having a small curvature radius. When a difference in flow velocity occurs in the bending portion, a flow velocity difference similar to that in the bending portion also occurs in the vicinity of the flow meter 106 located on the upstream side of the bending portion. In addition, pulsation occurs in the intake pipe 105 and the cylindrical member 104 due to the intake operation by the piston of the internal combustion engine. As a result of the entanglement of a plurality of factors such as the difference in flow velocity and pulsation described above, it is considered that the air flow in the vicinity of the flow meter 106 is disturbed and the detection signal from the flow meter 106 fluctuates.
[0006]
If a sufficiently long straight flow path can be secured between the flow meter 106 and the curved portion, the influence of the difference in flow velocity at the curved portion does not reach the vicinity of the flow meter 106, The fluctuation of the detection signal can be kept within the allowable range. However, when a sufficiently long straight flow path cannot be ensured between the flow meter 106 and the curved portion, the variation in the detection signal from the flow meter 106 cannot be kept within an allowable range. The flow rate cannot be measured accurately.
[0007]
The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a fluid pipe having a curved portion and a flow meter upstream of the curved portion. An object of the present invention is to provide an air cleaner that makes it possible to accurately measure the flow rate.
[0009]
[Means for Solving the Problems]
(1) The invention described in claim 1 is an air cleaner in which a cleaner element is provided between an air inlet and an air outlet, and an inlet of a fluid pipe is connected to the air outlet. And an inlet for introducing a fluid and a curved portion provided on the downstream side of the inlet, and a flow meter for measuring the flow rate of the fluid passing through the interior between the inlet and the curved portion. In the air cleaner to which the fluid pipe is connected, the opening edge of the inlet of the fluid pipe includes the measurement point of the flow meter and the fluid pipe in order to make the fluid velocity substantially uniform in a plane perpendicular to the axis of the fluid pipe As a rectifying means for rectifying the flow of the fluid from the inlet to the curved portion, it is configured to be inclined with respect to a plane perpendicular to the axis of the fluid piping. The gist is that the portion of the edge corresponding to the inner peripheral side of the curved portion protrudes in the axial direction of the fluid piping from the portion of the opening edge corresponding to the outer peripheral side of the curved portion. .
[0010]
(2) The invention according to claim 2 is an air cleaner in which a cleaner element is provided between an air inlet and an air outlet, and an inlet of a fluid pipe is connected to the air outlet, And an inlet for introducing a fluid and a curved portion provided on the downstream side of the inlet, and a flow meter for measuring the flow rate of the fluid passing through the interior between the inlet and the curved portion. In the air cleaner to which the fluid pipe is connected, the opening edge of the inlet of the fluid pipe includes the measurement point of the flow meter and the fluid pipe in order to make the fluid velocity substantially uniform in a plane perpendicular to the axis of the fluid pipe Is configured as a rectifying means for rectifying the flow of fluid from the inlet of the curved portion to the curved portion, and the inner circumference of the curved portion from the portion corresponding to the inner circumferential side of the curved portion of the opening edge It is summarized in that the distance to the end and is set larger than the distance to the outer periphery of an end of the curved portion the bending portion from the portion corresponding to the outer peripheral side of one of the opening edges.
[0011]
The rectifying means provided at the inlet of the fluid pipe includes a flow point of fluid flowing from the inlet to the curved portion so that the velocity of the fluid is substantially uniform in a plane including the measurement point of the flow meter and perpendicular to the axis of the fluid pipe. Rectify. In other words, in anticipation of a difference in the flow velocity of the fluid between the outer peripheral side and the inner peripheral side of the curved portion, the fluid piping should not cause a difference in the flow velocity in the vicinity of the flow meter affected by the difference in the flow velocity. The fluid flow is pre-adjusted by the rectifying means at the inlet portion of the air. Therefore, the disturbance of the fluid flow in the vicinity of the flow meter is suppressed.
That is, the fluid introduced from the opening edge portion corresponding to the inner peripheral side of the curved portion reaches the flow meter through a longer distance than the fluid introduced from the opening edge portion corresponding to the outer peripheral side of the curved portion. The This long distance becomes a running section for the fluid introduced into the fluid piping. Therefore, the fluid introduced from the opening edge portion corresponding to the inner peripheral side of the curved portion reaches the flow meter more than the fluid introduced from the opening edge portion corresponding to the outer peripheral side of the curved portion. However, the flow rate tends to increase. On the other hand, in the curved portion, the flow rate of the fluid flowing on the outer peripheral side tends to be faster than the flow rate of the fluid flowing on the inner peripheral side. Therefore, in the vicinity of the flow meter provided between the inlet of the fluid pipe and the curved portion, the flow velocity of the fluid flowing through the portion corresponding to the outer peripheral side of the curved portion and the portion corresponding to the inner peripheral side of the curved portion are The flow velocity of the flowing fluid is almost the same.
[0012]
(3) The invention described in claim 3 is an air cleaner in which a cleaner element is provided between an air inlet and an air outlet, and an inlet of a fluid pipe is connected to the air outlet. And an inlet for introducing a fluid and a curved portion provided on the downstream side of the inlet, and a flow meter for measuring the flow rate of the fluid passing through the interior between the inlet and the curved portion. In the air cleaner to which an object is connected, the inlet of the fluid pipe is arranged at the inlet of the fluid pipe so as to make the velocity of the fluid substantially uniform in a plane including the measurement point of the flow meter and perpendicular to the axis of the fluid pipe. A rectifying grid that functions as a rectifying means for rectifying the flow of fluid from the curved portion to the curved portion is provided, and the rectifying grid is a fluid flow resistance in a portion corresponding to the outer peripheral side of the curved portion. There has been a subject matter to be formed in larger aspect than the flow resistance of the fluid in the portion corresponding to the inner peripheral side of the curved portion.
[0013]
(4) The invention according to claim 4 is an air cleaner in which a cleaner element is provided between an air inlet and an air outlet, and an inlet of a fluid pipe is connected to the air outlet, And an inlet for introducing a fluid and a curved portion provided on the downstream side of the inlet, and a flow meter for measuring the flow rate of the fluid passing through the interior between the inlet and the curved portion. In the air cleaner to which an object is connected, the inlet of the fluid pipe is arranged at the inlet of the fluid pipe so as to make the velocity of the fluid substantially uniform in a plane including the measurement point of the flow meter and perpendicular to the axis of the fluid pipe. A rectifying grid that functions as a rectifying means for rectifying the flow of fluid from the bending portion to the bending portion is provided, and the rectifying lattice extends from a portion corresponding to the inner peripheral side of the bending portion to the outer peripheral side of the bending portion. Eye grating towards the corresponding parts is summarized in that formed in finer manner.
[0014]
The rectifying means provided at the inlet of the fluid pipe includes a flow point of fluid flowing from the inlet to the curved portion so that the velocity of the fluid is substantially uniform in a plane including the measurement point of the flow meter and perpendicular to the axis of the fluid pipe. Rectify. In other words, in anticipation of a difference in the flow velocity of the fluid between the outer peripheral side and the inner peripheral side of the curved portion, the fluid piping should not cause a difference in the flow velocity in the vicinity of the flow meter affected by the difference in the flow velocity. The fluid flow is pre-adjusted by the rectifying means at the inlet portion of the air. Therefore, the disturbance of the fluid flow in the vicinity of the flow meter is suppressed.
That is, the flow velocity of the fluid passing through the portion of the rectifying grid corresponding to the outer peripheral side of the bending portion is suppressed as compared with the flow velocity of the fluid passing through the portion of the rectifying lattice corresponding to the inner peripheral side of the bending portion. On the other hand, in the curved portion, the flow rate of the fluid flowing on the outer peripheral side tends to be faster than the flow rate of the fluid flowing on the inner peripheral side. Therefore, in the vicinity of the flow meter provided between the inlet of the fluid pipe and the curved portion, the flow velocity of the fluid flowing through the portion corresponding to the outer peripheral side of the curved portion and the portion corresponding to the inner peripheral side of the curved portion are The flow velocity of the flowing fluid is almost the same.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment in which the present invention is embodied in an air cleaner used in an internal combustion engine will be described below with reference to FIG.
[0017]
As shown in FIG. 1, the air cleaner 1 includes a lower body 2 having an opening on the upper surface, and an upper body 3 detachably fixed on the lower body 2 so as to cover the opening of the lower body 2. . The upper body 3 is fixed on the lower body 2 by a clamp (not shown). The cleaner element 4 is attached to the opening of the lower body 2, for example. The lower body 2 has an air inlet 5 on its lower surface. The upper body 3 has an air outlet 6, and an inlet 8 of an intake pipe 7 serving as a fluid pipe is connected to the air outlet 6. Although not shown in particular, the intake pipe 7 is connected to a cylinder of an internal combustion engine mounted in the engine room of the automobile.
[0018]
The inlet 8 of the intake pipe 7 opens into the upper body 3. The intake pipe 7 also has a curved portion 9 on the downstream side of the inlet 8. The air flow meter 10 is attached to the intake pipe 7 between the inlet 8 and the curved portion 9. The flow meter 10 is inserted into the intake pipe 7 so that the sensor element 11 provided at the tip thereof is disposed in the intake pipe 7. The flow meter 10 includes a cylindrical portion having an axis parallel to the axis L of the intake pipe 7 at the tip thereof, and the sensor element 11 is disposed in the cylindrical portion. The sensor element 11 is located at a measurement point for measuring the air flow rate.
[0019]
During the operation of the internal combustion engine, the air introduced into the air cleaner 1 from the air inlet 5 is purified by passing through the cleaner element 4 and then introduced into the inlet 8 of the intake pipe 7. Then, air is supplied from the inlet 8 through the curved portion 9 to the cylinder of the internal combustion engine. The sensor element 11 of the flow meter 10 outputs a detection signal corresponding to the flow rate of air passing through the cylindrical portion. Although not particularly shown, the detection signal from the sensor element 11 is sent to the engine control unit through wiring.
[0020]
The inlet 8 of the intake pipe 7 has an opening edge 8a that functions as a rectifying means. The opening edge 8a is inclined at a predetermined angle θ with respect to a plane P1 orthogonal to the axis L of the intake pipe 7. Due to this inclination, the portion of the opening edge 8 a corresponding to the inner peripheral side of the bending portion 9 protrudes in the direction of the axis L of the intake pipe 7 from the portion of the opening edge 8 a corresponding to the outer peripheral side of the bending portion 9. In other words, the distance D1 from the end of the bending portion 9 to the portion of the opening edge 8a corresponding to the inner peripheral side of the bending portion 9 is the opening edge 8a corresponding to the outer peripheral side of the bending portion 9 from the end of the bending portion 9. The distance D2 is larger than the distance D2.
[0021]
Next, the operation of the air cleaner 1 configured as described above will be described.
As described in the section of the prior art, when the air introduced from the inlet 8 of the intake pipe 7 passes through the curved portion 9, the air flowing on the outer peripheral side of the curved portion 9 having a large curvature radius has a larger curvature radius. The flow velocity becomes faster than the air flowing on the inner peripheral side of the small curved portion 9. The difference in flow velocity at the bending portion 9 also affects the air flow in the vicinity of the flow meter 10 located on the upstream side of the bending portion 9.
[0022]
However, in the present embodiment, due to the inclination of the opening edge 8 a of the inlet 8, the air introduced from the portion of the opening edge 8 a corresponding to the inner peripheral side of the curved portion 9 is opened to the outer peripheral side of the curved portion 9. It reaches the flow meter 10 through a longer distance than the air introduced from the portion 8a. This long distance (corresponding to the hatched area indicated by S in FIG. 1) is a running section for the air introduced into the intake pipe 7. Therefore, the air introduced from the portion of the opening edge 8 a corresponding to the inner peripheral side of the curved portion 9 is more flowmeter than the air introduced from the portion of the opening edge 8 a corresponding to the outer peripheral side of the curved portion 9. There is a tendency for the flow rate to increase to 10. On the other hand, as described above, in the bending portion 9, the flow velocity of the air flowing on the outer peripheral side tends to be faster than the flow velocity of the air flowing on the inner peripheral side. Therefore, in the vicinity of the flow meter 10 provided between the inlet 8 of the intake pipe 7 and the bending portion 9, the flow velocity of the air flowing through the portion corresponding to the outer peripheral side of the bending portion 9 and the inner periphery of the bending portion 9. The flow velocity of the air flowing through the portion corresponding to the side is almost the same.
[0023]
Thus, in anticipation of a difference in the flow velocity of the air between the outer peripheral side and the inner peripheral side of the bending portion 9, no difference in the flow velocity is generated in the vicinity of the flow meter 10 affected by the difference in the flow velocity. In addition, the air flow is adjusted in advance in the portion of the oblique inlet 8. In other words, the flow of air from the inlet 8 toward the curved portion 9 is rectified so that the flow velocity of air in the plane P2 including the measurement point of the flow meter 10 and perpendicular to the axis L of the intake pipe 7 is substantially uniform. The
[0024]
Therefore, in this embodiment, it is possible to suppress the turbulence of the air flow in the vicinity of the flow meter 10 and the fluctuation of the detection signal from the flow meter 10 due to the turbulence. According to the inventor's experiment, it has been confirmed that by adopting the intake pipe 7 of the present embodiment, the fluctuation of the detection signal from the flow meter 10 is within an allowable range, and the flow rate can be accurately measured. Yes. If the air flow rate can be accurately measured, the internal combustion engine can be well controlled based on the measurement result.
[0025]
In addition, since the above effect can be achieved with a simple configuration in which the opening edge 8a of the inlet 8 is formed in a slanted shape, the labor required for manufacturing can be reduced and the manufacturing cost can be reduced.
[0026]
Next, a second embodiment of the present invention will be described with reference to FIGS. 2 and 3, focusing on the differences from the first embodiment.
As shown in FIG. 2 and FIG. 3, in this embodiment, instead of forming the opening edge 8 a of the inlet 8 in an oblique shape, a rectifying grid 20 that functions as a rectifying means is provided at the inlet 8. The rectifying grid 20 may be attached to the intake pipe 7 as a separate object, or may be formed integrally with the intake pipe 7.
[0027]
The rectifying grid 20 is formed so that the grids that allow the passage of air gradually become finer from the portion corresponding to the inner peripheral side of the bending portion 9 toward the portion corresponding to the outer peripheral side of the bending portion 9. Yes. Therefore, the air passage resistance increases from the portion of the rectifying grid 20 corresponding to the inner peripheral side of the curved portion 9 toward the portion of the rectifying grid 20 corresponding to the outer peripheral side of the curved portion 9.
[0028]
For this reason, the flow velocity of the air passing through the portion of the rectifying grid 20 corresponding to the outer peripheral side of the bending portion 9 is compared with the flow velocity of the air passing through the portion of the rectifying lattice 20 corresponding to the inner peripheral side of the bending portion 9. It is suppressed. On the other hand, in the bending part 9, the flow velocity of the air flowing on the outer peripheral side tends to be faster than the flow velocity of the air flowing on the inner peripheral side. Therefore, in the vicinity of the flow meter 10 provided between the inlet 8 of the intake pipe 7 and the bending portion 9, the flow velocity of the air flowing through the portion corresponding to the outer peripheral side of the bending portion 9 and the inner periphery of the bending portion 9. The flow velocity of the air flowing through the portion corresponding to the side is almost the same. In other words, the flow of air from the inlet 8 toward the curved portion 9 is rectified so that the flow velocity of air in the plane P2 including the measurement point of the flow meter 10 and orthogonal to the axis L of the intake pipe 7 is substantially uniform. 20 is rectified.
[0029]
Therefore, also in the present embodiment, similarly to the first embodiment, it is possible to suppress the turbulence of the air flow in the vicinity of the flow meter 10 and the fluctuation of the detection signal from the flow meter 10 due to the turbulence.
[0030]
In addition, the flow of air introduced from the inlet 8 of the intake pipe 7 can be finely adjusted by adjusting the size of the rectifying grid 20.
FIG. 4 shows another embodiment of the rectifying grid. As shown in the figure, the rectifying grid 21 of the present embodiment includes a first grid portion 21a corresponding to the inner peripheral side of the curved portion 9, and a second grid portion 21b corresponding to the outer peripheral side of the curved portion 9. Have The lattice grid in the second grid section 21b is finer than the grid grid in the first grid section 21a. Therefore, the air passage resistance of the second lattice portion 21b is greater than that of the first lattice portion 21a. Therefore, the flow velocity of air passing through the second lattice portion 21b corresponding to the outer peripheral side of the bending portion 9 is compared with the flow velocity of air passing through the first lattice portion 21a corresponding to the inner peripheral side of the bending portion 9. Is suppressed.
[0031]
Therefore, in this embodiment, the same operation and effect as in the second embodiment can be obtained.
In particular, in the rectifying grid 21 of the present embodiment, the size of the grid is formed in two stages, so that it is more than that of the rectifying grid 20 of the second embodiment in which the size of the grid is continuously changed. Easy to manufacture.
[0032]
In addition, embodiment of this invention is not limited to said each embodiment, The following modifications are also possible.
In the embodiment of FIG. 1 or each of the embodiments of FIGS. 3 and 4, the inclination angle θ of the opening edge 8 a and the size of each rectifying grid 21, 20 are the diameter of the intake pipe 7 and the curvature of the curved portion 9. Or a bending angle, a distance from the flow meter 10 to the inlet 8, or a distance from the flow meter 10 to the curved portion 9 may be set as appropriate. That is, if the air flow can be rectified so that the flow velocity of air in the plane P2 including the measurement point of the flow meter 10 and orthogonal to the axis L of the intake pipe 7 can be almost uniform, the opening edge 8a. Any value may be employed as the inclination angle θ of the rectifier and the size of the eyes of the rectifying grids 21 and 20.
[0033]
In the embodiment of FIG. 1, the opening edge 8 a is provided on one plane that is inclined with respect to a plane P <b> 1 that is orthogonal to the axis L of the intake pipe 7. However, as shown by a two-dot chain line in FIG. 1, the opening edge 8 a has a bulging shape or a concave shape with respect to a plane inclined with respect to a plane P 1 orthogonal to the axis L of the intake pipe 7. Also good.
[0034]
In the embodiment of FIGS. 3 and 4, the eyes of the rectifying grids 21 and 20 are not limited to a square shape, and may have any shape such as a circular shape or a triangular shape.
Any type of flow meter 10 may be used as long as it is for measuring the flow rate of fluid.
[0035]
In each of the above embodiments, the present invention is embodied in the intake pipe of an air cleaner in an internal combustion engine. However, the present invention is not limited to the intake pipe of the air cleaner, and can be applied to any fluid pipe as long as it is a fluid pipe having a curved portion and having a flow meter upstream of the curved portion.
[0036]
In the following, in addition to the technical ideas described in the claims, technical ideas that can be grasped from the above embodiments will be described.
(1) The fluid pipe according to claim 1 or 2 , wherein the opening edge is provided on one plane inclined with respect to a plane orthogonal to the axis of the fluid pipe. In this way, manufacture becomes easy.
[0037]
(2) The rectifying grid is formed so that the mesh of the grid allowing the passage of fluid gradually becomes smaller from a portion corresponding to the inner peripheral side of the bending portion toward a portion corresponding to the outer peripheral side of the bending portion. The fluid piping according to claim 3 or 4 . In this way, the flow of the fluid introduced from the inlet can be finely adjusted.
[0038]
(3) The rectifying lattice includes a first lattice portion corresponding to the inner peripheral side of the curved portion and a second lattice portion corresponding to the outer peripheral side of the curved portion, and the lattice of the second lattice portion The fluid piping according to claim 3 or 4 , wherein the eyes are finer than the meshes of the lattice in the first lattice portion. In this way, since it is only necessary to form the lattice size in two stages, the manufacturing is easy.
[0039]
【The invention's effect】
As described above in detail, according to the present invention, the flow rate of the fluid passing through the curved fluid pipe can be accurately measured by the flow meter by rectifying the fluid flow by the rectifying means.
[0040]
When the rectifying means is configured by inclining the opening edge of the inlet, the labor required for manufacturing can be reduced and the manufacturing cost can be reduced.
When a rectifying grid is applied as the rectifying means, the flow of air introduced from the inlet can be finely adjusted.
[0041]
Further, when embodied as an air cleaner for an internal combustion engine, the flow rate of air passing through the intake pipe can be accurately measured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an air cleaner showing a first embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of an air cleaner showing a second embodiment of the present invention.
FIG. 3 is a front view of the rectifying grid in FIG. 2;
FIG. 4 is a front view of a rectifying grid according to another embodiment.
FIG. 5 is a cross-sectional view showing an air cleaner in the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Air cleaner, 4 ... Cleaner element, 5 ... Air introduction port, 6 ... Air discharge port, 7 ... Intake pipe as fluid piping, 8 ... Inlet, 8a ... Opening edge, 9 ... Curved part, 10 ... Air flow meter, 20 ... Rectification grid as rectification means, 21 ... Rectification grid as rectification means.

Claims

An air cleaner in which a cleaner element is provided between an air inlet and an air outlet, and an inlet of a fluid pipe is connected to the air outlet. The fluid pipe includes an inlet for introducing a fluid and an inlet of the inlet. In an air cleaner having a curved portion provided on the downstream side and having a flow meter for measuring the flow rate of fluid passing through the inside between the inlet and the curved portion,
The opening edge of the inlet of the fluid pipe includes a measurement point of the flow meter and the fluid from the inlet of the fluid pipe toward the curved portion in order to make the fluid velocity substantially uniform in a plane perpendicular to the axis of the fluid pipe. As a rectifying means for rectifying the flow of the fluid, the rectifying means is configured to be inclined with respect to a plane orthogonal to the axis of the fluid piping, and this inclination causes the curved portion of the opening edge to be on the inner peripheral side. The corresponding portion protrudes in the axial direction of the fluid piping from the portion corresponding to the outer peripheral side of the curved portion of the opening edge.
An air cleaner characterized by that.

An air cleaner in which a cleaner element is provided between an air inlet and an air outlet, and an inlet of a fluid pipe is connected to the air outlet. The fluid pipe includes an inlet for introducing a fluid and an inlet of the inlet. In an air cleaner having a curved portion provided on the downstream side and having a flow meter for measuring the flow rate of fluid passing through the inside between the inlet and the curved portion,
The opening edge of the inlet of the fluid pipe includes a measurement point of the flow meter and the fluid from the inlet of the fluid pipe toward the curved portion in order to make the fluid velocity substantially uniform in a plane perpendicular to the axis of the fluid pipe. The distance from the portion corresponding to the inner peripheral side of the curved portion of the opening edge to the inner peripheral end of the curved portion is the opening. It is set to be larger than the distance from the portion corresponding to the outer peripheral side of the curved portion of the edge to the outer peripheral end of the curved portion.
An air cleaner characterized by that.

An air cleaner in which a cleaner element is provided between an air inlet and an air outlet, and an inlet of a fluid pipe is connected to the air outlet. The fluid pipe includes an inlet for introducing a fluid and an inlet of the inlet. In an air cleaner having a curved portion provided on the downstream side and having a flow meter for measuring the flow rate of fluid passing through the inside between the inlet and the curved portion,
The flow of fluid from the inlet of the fluid pipe toward the curved portion in order to make the velocity of the fluid substantially uniform in the plane including the measurement point of the flow meter and perpendicular to the axis of the fluid pipe at the inlet of the fluid pipe A rectifying grid functioning as a rectifying means for rectifying the rectifying section is provided, and the rectifying grid is configured such that a fluid flow resistance in a portion corresponding to the outer peripheral side of the bending portion is in a portion corresponding to the inner peripheral side of the bending portion. Formed in a manner that is greater than the flow resistance of the fluid
An air cleaner characterized by that.

An air cleaner in which a cleaner element is provided between an air inlet and an air outlet, and an inlet of a fluid pipe is connected to the air outlet. The fluid pipe includes an inlet for introducing a fluid and an inlet of the inlet. In an air cleaner having a curved portion provided on the downstream side and having a flow meter for measuring the flow rate of fluid passing through the inside between the inlet and the curved portion,
The flow of fluid from the inlet of the fluid pipe toward the curved portion in order to make the velocity of the fluid substantially uniform in the plane including the measurement point of the flow meter and perpendicular to the axis of the fluid pipe at the inlet of the fluid pipe A rectifying grid functioning as a rectifying means for rectifying the rectifying portion is provided, and the rectifying lattice has a grid mesh from a portion corresponding to the inner peripheral side of the bending portion toward a portion corresponding to the outer peripheral side of the bending portion. Formed in a finer manner
An air cleaner characterized by that.