JP4259713B2

JP4259713B2 - Variable intake system for inline 4-cylinder internal combustion engine

Info

Publication number: JP4259713B2
Application number: JP2000025697A
Authority: JP
Inventors: 佳行海野
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2000-02-02
Filing date: 2000-02-02
Publication date: 2009-04-30
Anticipated expiration: 2020-02-02
Also published as: JP2001214747A

Description

【０００１】
【発明の属する技術分野】
本願の発明は、内燃機関の低回転速度域から高回転速度域まで広い回転速度域にわたって高い吸気充填効率と高い出力トルクとが得られるようにされた４気筒内燃機関の可変吸気装置の改良に関する。
【０００２】
【従来の技術】
従来より、多気筒内燃機関の各気筒に連通接続される吸気通路に発生する吸気圧力振動を利用して、各気筒における吸気行程の後半に、その気筒の吸気ポート部分の圧力を上昇させて、吸気過給効果を得るようにした吸気装置が種々提案されている。
【０００３】
例えば、内燃機関の吸気管の管路長や容積を内燃機関の回転数に応じて変えて、吸気の慣性過給効果や共鳴過給効果を得て、これらを適切に組み合わせ利用することにより、低回転速度域から高回転速度域まで広い回転速度域にわたって吸気充填効率を高く維持して、出力トルクを向上させることが行なわれている。
【０００４】
４気筒内燃機関においては、各気筒に連通する吸気管路長を内燃機関の低回転速度域、中回転速度域、高回転速度域の３段階に変えて、いずれも吸気の慣性過給効果を利用して、高い吸気充填効率を得て、出力トルクの向上を図ったもの（特公平７−３０６９８号公報）や、各気筒に連通する吸気管路を吸気行程が互いに連続しない気筒群毎に合流させた合流部を共鳴室とし、その上流側に共鳴管を気筒配列方向に沿って接続し、これら一対の共鳴管の上流側に集合部を設け、一対の共鳴室間の連通を内燃機関の低中回転速度域、高回転速度域にしたがって遮断、連通させて、吸気の共鳴過給効果および慣性過給効果を利用して、高い吸気充填効率を得て、出力トルクの向上を図ったもの（特開平１０−７３０２４号公報）等がある。
【０００５】
【発明が解決しようとする課題】
しかしながら、前者のものにおいては、各々が個別に作動し得る２つの吸気制御弁が必要であり、部品点数、重量が増大して、スペース的にも不利であるという難点があった。また、低中回転速度域において共鳴過給効果を利用した後者のものにおいては、共鳴室、共鳴管、集合部の設置が必要であり、一対の共鳴管を有することで気筒配列方向に吸気装置自体が大型化し、気筒配列方向にスペース的に不利があった。また、低中回転速度域と高回転速度域との狭間の部分におけるフラットな吸気充填効率が得られにくかった。
【０００６】
本願の発明は、従来の４気筒内燃機関の可変吸気装置が有する前記のような問題点を解決して、内燃機関の低回転速度域から高回転速度域まで広い回転速度域にわたって高い吸気充填効率を得ることができ、これにより、高い出力トルクを得ることができて、しかも、部品点数が少なく、構造を簡単化でき、スペースを要さない４気筒内燃機関の可変吸気装置を提供することを課題とする。
【０００７】
【課題を解決するための手段および効果】
本願の発明は、前記のような課題を解決した４気筒内燃機関の可変吸気装置に係り、その請求項１に記載された発明は、直列４気筒内燃機関の各気筒に一端がそれぞれ連通接続され、単一の吸気集合室に他端が連通接続される４つの互いに独立な吸気通路が、各気筒に一端がそれぞれ連通接続される部分の近傍の交差部分を除いて、吸気行程が互いに連続しない気筒群毎に気筒配列方向に平行に直列に配置され、内側に巻き込むように湾曲され、前記吸気通路の前記湾曲の内部空間に、前記吸気集合室が配置され、その外周の略１／３円弧長が前記吸気通路の途中に突出し、その外周の少なくとも残りの一部が前記吸気集合室の壁により抱持されるようにして、ロータリーバルブが設けられ、前記ロータリーバルブは、前記内燃機関の回転速度に応じて等間隔に３段階に切り換えられて、隣接する全ての吸気通路間もしくは吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の吸気通路間を連通もしくは遮断することができるようにされたことを特徴とする直列４気筒内燃機関の可変吸気装置である。
【０００８】
請求項１に記載された発明は、前記のように構成されているので、直列４気筒内燃機関の各気筒に一端がそれぞれ連通接続され、単一の吸気集合室に他端が連通接続される４つの互いに独立な吸気通路が、各気筒に一端がそれぞれ連通接続される部分の近傍の交差部分を除いて、吸気行程が互いに連続しない気筒群毎に気筒配列方向に平行に直列に配置され、内側に巻き込むように湾曲される。そして、その外周の略１／３円弧長がそれらの吸気通路の途中に突出、その外周の少なくとも残りの一部が前記吸気集合室の壁により抱持されるようにして、前記のような作用をするロータリーバルブが設けられている。
【０００９】
この結果、４つの互いに独立な吸気通路は、各気筒に一端がそれぞれ連通接続される部分の近傍の交差部分を除いて、互いに交差することがなく、また、可変吸気作用をするロータリーバルブが長さ方向に出っ張ることもなく、全体が側面視丸い形状にまとめられるので、吸気マニホールドを含む可変吸気装置を気筒配列方向を含めてコンパクトに形成することができて、スペース効率が良い。また、各吸気通路の等長化を図ることが容易である。
【００１０】
また、吸気通路の途中に、その外周の略１／３円弧長が突出するようにして、ロータリーバルブが設けられ、該ロータリーバルブは、内燃機関の回転速度に応じて等間隔に３段階に切り換えられて、隣接する全ての吸気通路間もしくは吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の吸気通路間を連通もしくは遮断することができるようにされる。
【００１１】
この結果、直列４気筒内燃機関の可変吸気装置が、吸気通路の途中にその外周の略１／３円弧長が突出するようにして設けられるロータリーバルブを、内燃機関の回転速度に応じて等間隔に３段階に切り換えるようにすることにより得られるので、バルブやアクチュエータ等の部品の点数が少なくなり、コストの低減、構造の簡単化、軽量化等に資することができ、スペースを要さない直列４気筒内燃機関の可変吸気装置を容易に得ることができる。また、ロータリーバルブは、その弁体および軸部が吸気通路内に突出しないので、吸気抵抗を増大させることがない。
【００１２】
さらに、請求項２記載のように請求項１記載の発明を構成することにより、ロータリーバルブは、その外周に、その軸方向から側面視して周方向に等間隔に仕切られた仮想３面を有し、該仮想３面が内燃機関の回転速度に応じて周方向に３段階に切り換えられて、内燃機関の低回転速度域で、隣接する全ての吸気通路間を遮断し、中回転速度域で、吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の吸気通路間を連通し、高回転速度域で、隣接する全ての吸気通路間を連通するようにされる。
【００１３】
この結果、仮想３面の各面側に、内燃機関の低、中、高回転速度域に応じてそれぞれの可変吸気作用を発揮する構造を付与すればよいので、ロータリーバルブの内部構造を比較的簡単に形成することができる。特に、内燃機関の中回転速度域で、吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される１対の吸気通路間を連通するのに、これら１対の吸気通路は互いに隣接し合っているのでこれらの間の仕切壁を削除するのみでよく、その連通路の構造をきわめて簡単に形成することができる。
【００１４】
また、仮想３面が内燃機関の回転速度に応じて周方向に３段階に切り換えられて、ロータリーバルブが前記のような作用をするので、内燃機関の低回転速度域においては、吸気集合室が大気開放部として作用して、ここが吸気圧力振動の反転室となり、燃焼室から吸気集合室までの長い独立した各吸気通路内での低い固有振動数の吸気圧力振動と機関の低回転に基づく吸気弁の長い開閉サイクルとが同調して、高い慣性過給効果が得られ、全ての気筒について高い吸気充填効率が得られて、出力トルクを向上させることができる。
【００１５】
また、中回転速度域においては、吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の吸気通路間の連通部より上流側の吸気通路部分が各気筒群の共鳴系を構成して、各吸気通路および吸気連通部内を吸気圧力波が反転することなく、同一気筒群における他の気筒の次の吸気行程にその吸気圧力波を伝播させることができ、高い共鳴過給効果が得られ、吸気行程が互いに連続しない気筒群における各気筒について高い吸気充填効率が得られて、出力トルクを向上させることができ、低回転速度域と高回転速度域との間の吸気充填効率と出力トルクとが低下する谷間の部分を埋め合わせることができる。
【００１６】
さらに、高回転速度域においては、隣接する全ての吸気通路間の連通部（連通室）が大気開放部として作用して、ここが吸気圧力振動の反転室となり、燃焼室から該連通部までの短い吸気通路内での高い固有振動数の吸気圧力振動と機関の高回転に基づく吸気弁の短い開閉サイクルとが同調して、高い慣性過給効果が得られ、全ての気筒について高い吸気充填効率が得られて、出力トルクを向上させることができる。
このようにして、低回転速度域から高回転速度域までの広い回転速度域にわたって、高い吸気充填効率と高い出力トルクとを得ることができる。
【００１７】
さらにまた、請求項３記載のように請求項１記載の発明を構成することにより、ロータリーバルブは、それぞれ外方に向けて開放された４つの互いに独立な通路と３つの連通室とを有し、該４つの互いに独立な通路は、ロータリーバルブの外周を周方向に等間隔に３分割して得られる正三角形の２つの頂点間にまたがり、４つの互いに独立な吸気通路の並設長に及ぶ長さを有する第１の仕切壁と、該第１の仕切壁に連設されて、隣接する吸気通路間を遮断する３つの第２の仕切壁とにより区画形成され、該３つの連通室のうちの２つは、正三角形の残りの１つの頂点と該第１の仕切壁の一方の端縁もしくは該端縁近傍の点との間にまたがり、４つの互いに独立な吸気通路の並設長に及ぶ長さを有する第３の仕切壁と、少なくとも該第３の仕切壁に連設されて、中央２つの隣接する吸気通路間を遮断する第４の仕切壁とによりそれぞれ区画形成され、該３つの連通室のうちの残りの１つは、該４つの互いに独立な通路および該３つの連通室のうちの２つを除いた空間により形成されている。
【００１８】
この結果、ロータリーバルブを内燃機関の回転速度に応じて等間隔に３段階に切り換えて、隣接する全ての吸気通路間もしくは吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の吸気通路間を連通もしくは遮断することができるロータリーバルブの内部構造を、ロータリーバルブの内部を第１〜第４の仕切壁により仕切って、４つの互いに独立な通路と３つの連通室とを形成するという、比較的簡単な方法により得ることができる。
【００１９】
【発明の実施の形態】
以下、図１ないし図８に図示される本願の請求項１ないし請求項８に記載された発明の一実施形態について説明する。
図１は、本実施形態における直列４気筒内燃機関の可変吸気装置を吸気通路部分について吸気通路に沿って上半分を切断して仮想して見た概略斜視図であって、内燃機関が低回転速度域にあるときのロータリーバルブの回転状態と吸気の流れ状態とを併せて示した図、図２は、図１の可変吸気装置の横断面図であって、吸気通路を完全体で示した図、図３は、図１と同様の図であって、内燃機関が中回転速度域にあるときのロータリーバルブの回転状態と吸気の流れ状態とを併せて示した図、図４は、図２と同様の図であって、図３の可変吸気装置の横断面図、図５は、図１と同様の図であって、内燃機関が高回転速度域にあるときのロータリーバルブの回転状態と吸気の流れ状態とを併せて示した図、図６は、図２と同様の図であって、図５の可変吸気装置の横断面図、図７は、図１の可変吸気装置の作用を説明するための図、図８は、図１の可変吸気装置の特性線図である。なお、以下において、気筒配列方向を左右方向とし、図１において左方を左方とする。
【００２０】
図１および図２において、本実施形態における直列４気筒内燃機関の可変吸気装置１は、内燃機関の第１〜第４気筒♯１〜♯４（図示されず）の各気筒に一端がそれぞれ連通接続され、単一の吸気集合室５に他端が連通接続される４つの互いに独立な第１〜第４吸気通路４₁ 〜４₄ を有する吸気マニホールド２を備えている。
【００２１】
第１〜第４気筒♯１〜♯４は、第１気筒♯１、第３気筒♯３、第４気筒♯４、第２気筒♯２の順に点火される。したがって、各気筒における吸気行程も、この順となり、第１、第４気筒♯１、♯４からなる気筒群と、第２、第３気筒♯２、♯３からなる気筒群とは、吸気行程が互いに連続しない気筒群である。
【００２２】
第１〜第４吸気通路４₁ 〜４₄ は、各気筒♯１〜♯４に一端がそれぞれ連通接続される部分の近傍の交差部分（図１において、第４吸気通路４₄ の上方湾曲部分が第２、第３吸気通路４₂ 、４₃ の上方湾曲部分と交差している部分）を除いて、吸気行程が互いに連続しない気筒群♯１、♯４と♯２、♯３毎に第１、第４吸気通路４₁ 、４₄ と第２、第３吸気通路４₂ 、４₃ とに纏められて、気筒配列方向に平行且つ直列に配置されている。したがって、第１、第４吸気通路４₁ 、４₄ の各々は、気筒配列方向左半において互いに隣接し合っており、第２、第３吸気通路４₂ 、４₃ の各々は、気筒配列方向右半において互いに隣接し合っている。
【００２３】
これより、吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の吸気通路は、第１、第４気筒♯１、♯４からなる気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の第１、第４吸気通路４₁ 、４₄ と、第２、第３気筒♯２、♯３からなる気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の第２、第３吸気通路４₂ 、４₃ とである。
【００２４】
第１〜第４吸気通路４₁ 〜４₄ は、略等長にされ、図２に図示されるように、丸く内側に巻き込まれるようにして湾曲されて形成されており、その先端に吸気集合室５が連通接続されている。この吸気集合室５は、この吸気集合室５に隣接して設けられた吸気ダクト６とともに、第１〜第４吸気通路４₁ 〜４₄ の湾曲の内部空間に抱持されるようにして設けられていて、可変吸気装置１のコンパクト化が図られている。
【００２５】
図示されないエアクリーナ、スロットルボディを経て吸気ダクト６に導かれた吸気は、次いで、比較的大容積からなる吸気集合室５に流入し、ここに集合させられる。そして、内燃機関の回転数が低中回転速度域にあるとき、ここからさらに第１〜第４吸気通路４₁ 〜４₄ のそれぞれに分かれて流入して、これらの比較的長い通路を流れて、第１〜第４気筒♯１〜♯４のそれぞれに吸入される。吸気ダクト６と吸気集合室５との連通路は、図示されてはいないが、吸気集合室５の長さ方向の中央部に設けられ、これにより、吸気集合室５から各気筒♯１〜♯４に至る第１〜第４吸気通路４₁ 〜４₄ を含む吸気通路長の等長化が図られている。
【００２６】
第１〜第４吸気通路４₁ 〜４₄ のそれぞれの途中の底壁には、正面視略矩形状の第１〜第４開口７₁ 〜７₄ が形成されており、これらの第１〜第４開口７₁ 〜７₄ からその一部を第１〜第４吸気通路４₁ 〜４₄ のそれぞれに突出させるようにして、単一体からなるロータリーバルブ３が設けられている。このロータリーバルブ３の第１〜第４吸気通路４₁ 〜４₄ への突出部分は、ロータリーバルブ３を軸方向から側面視した場合、その略１／３円弧長で切り取られる三日月状部分に相当する（図２参照）。
【００２７】
このロータリーバルブ３は、第１〜第４吸気通路４₁ 〜４₄ のそれぞれに突出する側面視略１／３円弧部分を除いた残りの部分が吸気マニホールド２の本体壁部分８により抱持されて、配置されている。この本体壁部分８は、側面視略２／３円弧状をなしていて、ロータリーバルブ３の後述する第１、第２連通室10、12をロータリーバルブ３の回転位置に応じて閉鎖することができる。本体壁部分８の略半分は、吸気集合室５の壁の一部をなしている。
【００２８】
次に、ロータリーバルブ３の構造と作用、効果について詳細に説明する。
ロータリーバルブ３は、図２に図示されるように、その外周に、その軸方向から側面視して周方向に等間隔に仕切られた仮想３面ａ、ｂ、ｃを有し、これら仮想３面ａ、ｂ、ｃが内燃機関の回転速度に応じて周方向に３段階に切り換えられることにより、以下に詳しく説明されるように、隣接する吸気通路４₁ と４₄ 、４₄ と４₂ 、４₂ と４₃ 間もしくは吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の第１、第４吸気通路４₁ 、４₄ 間、第２、第３吸気通路４₂ 、４₃ 間を連通もしくは遮断することができるようにされている。
【００２９】
ロータリーバルブ３の仮想３面ａ、ｂ、ｃのうちの１面ａ側は、図５および図６に図示されるように、隣接する吸気通路４₁ と４₄ 、４₄ と４₂ 、４₂ と４₃ 間を連通することができる大容積の第１の連通室10を有する。
【００３０】
この第１の連通室10は、１面ａ側と他の１面ｂ側とをロータリーバルブ３の全長にわたって仕切る仕切壁（第３の仕切壁）14と１面ａ側および他の１面ｂ側とさらに他の１面ｃ側とをロータリーバルブ３の全長にわたって仕切る仕切壁（第１の仕切壁）15とにより挟まれて、ロータリーバルブ３の内方に凹入するような形状に形成され、第１〜第４吸気通路４₁ 〜４₄ の各断面積および後述する第２の連通室12の断面積よりも大きい断面積を有し、第１〜第４吸気通路４₁ 〜４₄ の各断面形状を急激に変化させつつ、これらの吸気通路の全てを連通する。
【００３１】
ロータリーバルブ３の仮想３面ａ、ｂ、ｃのうちの他の１面ｂ側は、図３および図４に図示されるように、吸気行程が互いに連続しない気筒群♯１、♯４と♯２、♯３における各気筒に一端がそれぞれ連通接続される隣接する１対の第１、第４吸気通路４₁ 、４₄ 、隣接する１対の第２、第３吸気通路４₂ 、４₃ の各間をそれぞれ連通することができる連通室12₁ 、連通室12₂ を有している。これら２つの連通室12₁ 、12₂ をまとめて、第２の連通室12と呼ぶこととする。
【００３２】
第２の連通室12のうちの１つである連通室12₁ 、他の１つである連通室12₂ は、仕切壁（第３の仕切壁）14と仕切壁（第１の仕切壁）15と中央２つの第４、第２吸気通路４₄ 、４₂ 間を仕切る仕切壁（第４の仕切壁）16とにより囲まれて、それぞれ形成されている。仕切壁（第３の仕切壁）14は、連通室12₁ 、12₂ の断面積が各吸気通路４₁ 〜４₄ の断面積に略等しくなるように、ロータリーバルブ３の内方に凹まされた形状に形成されている。
【００３３】
これら第１の連通室10、第２の連通室12（12₁ 、12₂ ）は、ロータリーバルブ３が図１、図２に図示される回転位置にあるとき、吸気マニホールド２の本体壁部分８により同時に閉鎖される。
【００３４】
ロータリーバルブ３の仮想３面ａ、ｂ、ｃのうちのさらに他の１面ｃ側は、図１および図２に図示されるように、隣接する吸気通路４₁ と４₄ 、４₄ と４₂ 、４₂ と４₃ 間をそれぞれ遮断する仕切壁を有している。この仕切壁は、これらの吸気通路間をそれぞれ仕切る三日月状仕切壁（第２の仕切壁の１〜３）17〜19と、前記した仕切壁（第１の仕切壁）15とから構成されている。そして、ロータリーバルブ３が図１および図２に図示される回転位置にあるとき、隣接する吸気通路４₁ と４₄ 、４₄ と４₂ 、４₂ と４₃ 間をそれぞれ遮断して、完全に独立した長い吸気通路４₁ 〜４₄ を形成する４つの独立な通路部分を提供する。
【００３５】
この仕切壁15は、各吸気通路４₁ 〜４₄ の通路長さ方向に沿う断面形状を変化させないように、各通路内に突出するように湾曲され、また、各吸気通路４₁ 〜４₄ の通路長さ方向と直交する方向に沿う断面形状を変化させないように、ロータリーバルブ内方にわずかに凹むように湾曲されて、形成されている。
【００３６】
第１〜第４の仕切壁14〜19、第１、第２の連通室10、12（12₁ 、12₂ ）について、さらに詳細に説明する。
第１の仕切壁15は、ロータリーバルブ３の外周を周方向に等間隔に３分割して得られる正三角形の２つの頂点間にまたがり、４つの互いに独立な吸気通路４₁ 〜４₄ の並設長に及ぶ長さを有している。３つの第２の仕切壁17〜19は、第１の仕切壁15に連設されて、三日月状を呈し、隣接する吸気通路４₁ と４₄ 、４₄ と４₂ 、４₂ と４₃ 間を遮断する。第３の仕切壁14は、正三角形の残りの１つの頂点と第１の仕切壁15の一方（図２において上方）の端縁の近傍の点との間にまたがり、４つの互いに独立な吸気通路４₁ 〜４₄ の並設長に及ぶ長さを有している。第４の仕切壁16は、第３の仕切壁14および第１の仕切壁15に第１の仕切壁15の一方の端縁の側において連設されて、中央２つの隣接する吸気通路４₄ 、４₂ 間を遮断する。第１の連通室10と第２の連通室12（12₁ 、12₂ ）とは、第３の仕切壁14を境にして背中合わせに配置されている。ロータリーバルブ３は、その内部に合計３つの区画された連通室10、12₁ 、12₂ を有する。
【００３７】
ロータリーバルブ３は、仮想３面ａ、ｂ、ｃのうちのいずれかが第１〜第４吸気通路４₁ 〜４₄ の第１〜第４開口７₁ 〜７₄ に面するように、内燃機関の回転速度に応じて等間隔に３段階に切換可能な制御手段を備えている。この制御手段には、電動もしくは負圧アクチュエータ（図示されず）が使用される。
【００３８】
これらのアクチュエータは、ロータリーバルブ３の一側端側の吸気装置１に配設される。ロータリーバルブ３は、内燃機関の回転速度に応じて段階的に順次作動するようになっており、内燃機関の回転速度の増減に応じて正方向に、また、逆方向に回転する。電動アクチュエータの場合、制御手段の信号により、電動モータを段階的に作動させるだけでよい。負圧アクチュエータの場合、負圧室を少なくとも２室備えたダイヤフラムが必要であり、その各々に制御弁を設け、内燃機関の回転速度に応じて順に制御弁を作動させ負圧導入することで、ロータリーバルブ３の段階的な作動が可能になり、その負圧の導入（指示）を制御手段が行なう。その負圧は、スロットルバルブの下流から導入され、負圧チャンバーを介して各制御弁に分配される。
【００３９】
この制御手段は、内燃機関の回転速度に応じて、ロータリーバルブ３を次のように切換制御する。
先ず、この制御手段は、内燃機関の回転数が所定の回転数Ｎ₁ より低い低回転速度域ある場合（Ｎ＜Ｎ₁ ）においては、図１および図２に図示されるように、ロータリーバルブ３の仮想３面ａ、ｂ、ｃのうちのさらに他の１面ｃ側が第１〜第４吸気通路４₁ 〜４₄ の第１〜第４開口７₁ 〜７₄ に面するようにロータリーバルブ３を切換制御する。これにより、隣接する吸気通路４₁ と４₄ 、４₄ と４₂ 、４₂ と４₃ 間が仕切壁15、仕切壁17〜19により全て遮断され、完全に独立した長い第１〜第４吸気通路４₁ 〜４₄ が形成される。
【００４０】
そして、吸気集合室５内の吸気は、これらの長い第１〜第４吸気通路４₁ 〜４₄ にそれぞれ流入し、これらの吸気通路４₁ 〜４₄ を流れて、各気筒♯１〜♯４に供給される。このとき、吸気集合室５は、大気開放部として作用して、ここが吸気圧力振動の反転室となり、燃焼室から吸気集合室５までの長い吸気通路４₁ 〜４₄ 内での低い固有振動数の吸気圧力振動と機関の低回転に基づく吸気弁の長い開閉サイクルとが同調して、高い慣性過給効果が得られ、全ての気筒について高い吸気充填効率が得られて、出力トルクを向上させることができる（図７、図８の▲１▼参照）。
【００４１】
次に、この制御手段は、内燃機関の回転数がＮ₁ より高く、所定の回転数Ｎ₂ （Ｎ₁ ＜Ｎ₂ ）より低い中回転速度域にある場合（Ｎ₁ ＜Ｎ＜Ｎ₂ ）においては、図３および図４に図示されるように、ロータリーバルブ３の仮想３面ａ、ｂ、ｃのうちの他の１面ｂ側が第１〜第４吸気通路４₁ 〜４₄ の第１〜第４開口７₁ 〜７₄ に面するようにロータリーバルブ３を切換制御する。これにより、吸気行程が互いに連続しない気筒群♯１、♯４、気筒群♯２、♯３における各気筒に一端がそれぞれ連通接続される１対の第１、第４吸気通路４₁ 、４₄ 間、１対の第２、第３吸気通路４₂ 、４₃ 間が、それぞれ連通室12₁ 、12₂ を介して連通される。
【００４２】
そして、これら１対の第１、第４吸気通路４₁ 、４₄ 間、１対の第２、第３吸気通路４₂ 、４₃ 間の各連通部（第２の連通室12を構成する連通室12₁ 、12₂ ）より上流側の各吸気通路部分４_1u、４_4uの組と４_2u、４_3uの組とが、各気筒群の共鳴系を構成して、各吸気通路４₁ 〜４₄ および各吸気連通部（連通室12₁ 、12₂ ）内を吸気圧力波が反転することなく、同一気筒群における他の気筒の次の吸気行程にその吸気圧力波を伝播させることができ、高い共鳴過給効果が得られ、吸気行程が互いに連続しない気筒群♯１、♯４と♯２、♯３における各気筒について高い吸気充填効率が得られて、出力トルクを向上させることができる。このようにして、低回転速度域と高回転速度域との間の吸気充填効率と出力トルクとが低下する谷間の部分を埋め合わせることができる（図７、図８の▲２▼参照）。
【００４３】
さらに次に、この制御手段は、内燃機関の回転数がＮ₂ より高い高回転速度域にある場合（Ｎ₂ ＜Ｎ）においては、図５および図６に図示されるように、ロータリーバルブ３の仮想３面ａ、ｂ、ｃのうちの１面ａ側が第１〜第４吸気通路４₁ 〜４₄ の第１〜第４開口７₁ 〜７₄ に面するようにロータリーバルブ３を切換制御する。これにより、隣接する吸気通路４₁ と４₄ 、４₄ と４₂ 、４₂ と４₃ 間が全て連通されて、第１〜第４吸気通路４₁ 〜４₄ は、全て互いに連通状態になる。
【００４４】
このとき、大容積に形成されている第１の連通室10は、第１〜第４吸気通路４₁ 〜４₄ の各断面形状を急激に変化させるので、ここが大気開放部として作用して、吸気圧力振動の反転室となり、燃焼室から該第１の連通室10までの短い吸気通路部分４_1d〜４_4d内での高い固有振動数の吸気圧力振動と機関の高回転に基づく吸気弁の短い開閉サイクルとが同調して、高い慣性過給効果が得られ、全ての気筒について高い吸気充填効率が得られて、出力トルクを向上させることができる（図７、図８の▲３▼参照）。
【００４５】
このようにして、内燃機関の低回転速度域から高回転速度域までの広い回転速度域にわたって、フラットな高い吸気充填効率と高い出力トルクとを得ることができる。一般に、慣性過給と共鳴過給とを比較すると、その効果は、慣性過給の方が大きく、共鳴過給は慣性過給を補う効果として位置付けられるが、本実施形態においては、前記のとおり、低回転速度域において得られる慣性過給効果に基づく高い吸気充填効率と高回転速度域において得られる慣性過給効果に基づく高い吸気充填効率との間の谷間の部分が、中回転速度域において得られる共鳴過給効果に基づく吸気充填効率の向上により十分に補われている。なお、内燃機関の全回転速度域にわたって、吸気は常に吸気集合室５から各気筒♯１〜♯４に供給されていることに変わりはない。
【００４６】
本実施形態は、前記のように構成されているので、さらに、次のような効果を奏することができる。
直列４気筒内燃機関の各気筒に一端がそれぞれ連通接続され、単一の吸気集合室５に他端が連通接続される４つの互いに独立な第１〜第４吸気通路４₁ 〜４₄ が、各気筒に一端がそれぞれ連通接続される部分の近傍の交差部分を除いて、吸気行程が互いに連続しない気筒群毎に気筒配列方向に平行に直列に配置される。そして、これらの吸気通路４₁ 〜４₄ の途中に、その外周の略１／３円弧長が突出するようにして、ロータリーバルブ３が設けられている。
【００４７】
この結果、第１〜第４吸気通路４₁ 〜４₄ は、各気筒に一端がそれぞれ連通接続される部分の近傍の交差部分を除いて、互いに交差することがなく、また、可変吸気作用をするロータリーバルブ３が長さ方向に出っ張ることもなく、吸気マニホールド２を含む可変吸気装置１を特に気筒配列方向においてコンパクトに形成することができて、スペース効率が良い。また、各吸気通路４₁ 〜４₄ の等長化を図ることが容易である。
【００４８】
また、低回転速度域から高回転速度域までの広い回転速度域にわたる高い吸気充填効率と高い出力トルクとが、第１〜第４吸気通路４₁ 〜４₄ の途中にその外周の略１／３円弧長が突出するようにして設けられるロータリーバルブ３を内燃機関の回転速度に応じて等間隔に３段階に切換制御することにより得られるので、バルブやアクチュエータ等の部品の点数が少なくなり、コストの低減、構造の簡単化、軽量化等に資することができ、スペースを要さない４気筒内燃機関の可変吸気装置１を容易に得ることができる。また、ロータリーバルブ３は、その弁体および軸部が第１〜第４吸気通路４₁ 〜４₄ 内に突出しないので、吸気抵抗を増大させることがない。
【００４９】
また、ロータリーバルブ３は、電動もしくは負圧アクチュエータにより切換作動されるので、ロータリーバルブ３を内燃機関の回転速度に応じて等間隔に３段階に切換制御する制御手段の構成が容易になる。
【００５０】
さらに、ロータリーバルブ３は、その外周に、その軸方向から側面視して周方向に等間隔に仕切られた仮想３面ａ、ｂ、ｃを有し、該仮想３面ａ、ｂ、ｃが内燃機関の回転速度に応じて周方向に３段階に切り換えられて、内燃機関の低回転速度域で、隣接する全ての吸気通路４₁ と４₄ 、４₄ と４₂ 、４₂ と４₃ 間を遮断し、中回転速度域で、吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される隣接する１対の第１、第４吸気通路４₁ 、４₄ 間、１対の第２、第３吸気通路４₂ 、４₃ 間を連通し、高回転速度域で、隣接する全ての吸気通路４₁ と４₄ 、４₄ と４₂ 、４₂ と４₃ 間を連通するようにされる。
【００５１】
この結果、仮想３面ａ、ｂ、ｃの各面側に、内燃機関の低、中、高回転速度域に応じてそれぞれの可変吸気作用を発揮する構造を付与すればよいので、ロータリーバルブ３の内部構造を比較的簡単に形成することができる。特に、内燃機関の中回転速度域で、吸気行程が互いに連続しない気筒群における各気筒に一端がそれぞれ連通接続される１対の第１、第４吸気通路４₁ 、４₄ 間、１対の第２、第３吸気通路４₂ 、４₃ 間を連通するのに、これら各対における吸気通路は互いに隣接し合っているのでこれらの間の仕切壁を削除するのみでよく、その連通路（第２の連通室12（12₁ 、12₂ ））の構造をきわめて簡単に形成することができる。
【００５２】
また、第１〜第４吸気通路４₁ 〜４₄ は、内側に巻き込むように湾曲され、その湾曲の内部空間に、吸気集合室５および吸気ダクト６が配置され、ロータリーバルブ３は、その外周の一部が該吸気集合室３の壁により抱持されるようにして配置されるので、可変吸気装置１は、全体が側面視丸い形状に纏められ、可変吸気装置１をさらにコンパクトに形成することができて、スペース効率がさらに良くなる。
【００５３】
なお、第１の連通室10、第２の連通室12（12₁ 、12₂ ）、仕切壁14、15の構造は、本実施形態の図示のものに限定されず、種々の変形が可能である。
【図面の簡単な説明】
【図１】本実施形態における直列４気筒内燃機関の可変吸気装置を、吸気通路部分について吸気通路に沿って上半分を切断して仮想して見た概略斜視図であって、内燃機関が低回転速度域にあるときのロータリーバルブの回転状態と吸気の流れ状態とを併せて示した図である。
【図２】図１の可変吸気装置の横断面図である。
【図３】図１と同様の図であって、内燃機関が中回転速度域にあるときのロータリーバルブの回転状態と吸気の流れ状態とを併せて示した図である。
【図４】図２と同様の図であって、図３の可変吸気装置の横断面図である。
【図５】図１と同様の図であって、内燃機関が高回転速度域にあるときのロータリーバルブの回転状態と吸気の流れ状態とを併せて示した図である。
【図６】図２と同様の図であって、図５の可変吸気装置の横断面図である。
【図７】本実施形態における直列４気筒内燃機関の可変吸気装置の作用を説明するための図である。
【図８】本実施形態における直列４気筒内燃機関の可変吸気装置の特性線図である。
【符号の説明】
１…可変吸気装置、２…吸気マニホールド、３…ロータリーバルブ、４₁ 〜４₄ …第１〜第４吸気通路、４_1u〜４_4u…上流側吸気通路部分、４_1d〜４_4d…下流側吸気通路部分、５…吸気集合室、６…吸気ダクト、７₁ 〜７₄ …第１〜第４開口、８…本体壁部分、10…第１の連通室、12（12₁ 、12₂ ）…第２の連通室、14…第３の仕切壁、15…第１の仕切壁、16…第４の仕切壁、17〜19…３つの第２の仕切壁、ａ〜ｃ…仮想３面。[0001]
BACKGROUND OF THE INVENTION
The invention of the present application relates to an improvement of a variable intake device for a four-cylinder internal combustion engine that is configured to obtain high intake charging efficiency and high output torque over a wide rotational speed range from a low rotational speed range to a high rotational speed range of the internal combustion engine. .
[0002]
[Prior art]
Conventionally, using the intake pressure vibration generated in the intake passage connected to each cylinder of the multi-cylinder internal combustion engine, in the second half of the intake stroke in each cylinder, the pressure of the intake port portion of the cylinder is increased, Various intake devices have been proposed that achieve an intake supercharging effect.
[0003]
For example, by changing the pipe length and volume of the intake pipe of the internal combustion engine according to the number of revolutions of the internal combustion engine to obtain the inertial supercharging effect and the resonant supercharging effect of the intake air, by appropriately using these in combination, The intake torque efficiency is maintained high over a wide rotational speed range from a low rotational speed range to a high rotational speed range, and output torque is improved.
[0004]
In a four-cylinder internal combustion engine, the intake pipe length communicating with each cylinder is changed into three stages of the low rotation speed range, medium rotation speed range, and high rotation speed range of the internal combustion engine. Used to obtain high intake charge efficiency and improve output torque (special public No. 7-30698), or a confluence section where the intake pipes communicating with each cylinder join together for each cylinder group in which the intake strokes do not continue to each other is used as a resonance chamber, and a resonance pipe is provided upstream in the cylinder arrangement direction. Resonance of the intake air by providing a collecting part upstream of the pair of resonance tubes and blocking and communicating the communication between the pair of resonance chambers according to the low / medium speed range and the high speed range of the internal combustion engine. There are some which have used high supercharging effect and inertial supercharging effect to obtain high intake charge efficiency and improve output torque (Japanese Patent Laid-Open No. 10-73024).
[0005]
[Problems to be solved by the invention]
However, in the former, two intake control valves each capable of operating individually are necessary, and the number of parts and weight are increased, which is disadvantageous in terms of space. Further, in the latter type using the resonance supercharging effect in the low / medium rotational speed region, it is necessary to install a resonance chamber, a resonance tube, and a collecting portion. By having a pair of resonance tubes, an intake device is arranged in the cylinder arrangement direction. The size of the cylinder itself increased, and there was a disadvantage in terms of space in the cylinder arrangement direction. In addition, it is difficult to obtain a flat intake charging efficiency in a portion between the low and medium rotation speed range and the high rotation speed range.
[0006]
The invention of the present application solves the above-mentioned problems of the conventional variable intake system of a four-cylinder internal combustion engine, and achieves high intake charging efficiency over a wide rotational speed range from a low rotational speed range to a high rotational speed range of the internal combustion engine. Thus, it is possible to obtain a variable intake device for a four-cylinder internal combustion engine that can obtain a high output torque, can reduce the number of components, can be simplified in structure, and does not require a space. Let it be an issue.
[0007]
[Means for solving the problems and effects]
The invention of the present application relates to a variable intake system for a four-cylinder internal combustion engine that solves the above-described problems. The invention described in claim 1 is configured such that one end is connected to each cylinder of an in-line four-cylinder internal combustion engine. The four independent intake passages whose other ends are connected in communication with the single intake air collecting chamber are not connected to each other except for the intersection near the portion where one end is connected to each cylinder. Each cylinder group is arranged in series in parallel with the cylinder arrangement direction, is curved so as to be wound inside, and the intake air collecting chamber is arranged in the curved internal space of the intake passage, and is substantially １／ arc of the outer periphery thereof. A rotary valve is provided such that the length protrudes in the middle of the intake passage and at least the remaining part of the outer periphery thereof is held by the wall of the intake air collecting chamber, and the rotary valve rotates the internal combustion engine. Speed Are switched at three steps at equal intervals, and communicated between a pair of adjacent intake passages, one end of which is connected to each cylinder in a group of cylinders where the intake strokes are not continuous with each other. Alternatively, it is a variable intake device for an in-line four-cylinder internal combustion engine characterized in that it can be shut off.
[0008]
Since the invention described in claim 1 is configured as described above, one end is connected to each cylinder of the in-line four-cylinder internal combustion engine, and the other end is connected to the single intake manifold. Four mutually independent intake passages are arranged in series in parallel to the cylinder arrangement direction for each cylinder group in which the intake strokes are not continuous with each other, except for an intersection near a portion where one end of each cylinder is connected in communication. Curved to wrap inside. Then, approximately 1/3 arc length of the outer periphery protrudes in the middle of the intake passage, and at least the remaining part of the outer periphery is held by the wall of the intake air collecting chamber. A rotary valve is provided.
[0009]
As a result, the four independent intake passages do not intersect each other except for an intersection near the portion where one end of each cylinder is connected to each other, and the rotary valve that performs variable intake action is long. Since the whole is gathered into a round shape when viewed from the side without protruding in the vertical direction, the variable intake device including the intake manifold can be formed compactly including the cylinder arrangement direction, and the space efficiency is good. Further, it is easy to make each intake passage the same length.
[0010]
In addition, a rotary valve is provided in the middle of the intake passage so that approximately 1/3 arc length of the outer circumference protrudes, and the rotary valve is switched in three steps at equal intervals according to the rotational speed of the internal combustion engine. Thus, it is possible to communicate or block between a pair of adjacent intake passages whose one ends are connected to each cylinder in a cylinder group in which the intake strokes are not continuous with each other between all adjacent intake passages. .
[0011]
As a result, the variable intake device of the in-line four-cylinder internal combustion engine is provided with a rotary valve provided so that approximately 1/3 arc length of the outer periphery protrudes in the middle of the intake passage at equal intervals according to the rotational speed of the internal combustion engine. Since the number of parts such as valves and actuators can be reduced, the cost can be reduced, the structure can be simplified, and the weight can be reduced. A variable intake device for a four-cylinder internal combustion engine can be easily obtained. Further, since the valve body and the shaft portion of the rotary valve do not protrude into the intake passage, the intake resistance is not increased.
[0012]
Further, by configuring the invention according to claim 1 as described in claim 2, the rotary valve has three virtual surfaces that are partitioned at equal intervals in the circumferential direction as viewed from the side in the axial direction. The virtual three planes are switched in three stages in the circumferential direction according to the rotational speed of the internal combustion engine, and in the low rotational speed range of the internal combustion engine, all adjacent intake passages are blocked, and the intermediate rotational speed range In the cylinder group in which the intake strokes do not continue to each other, each cylinder is connected to a pair of adjacent intake passages whose one ends are connected to each other, and all adjacent intake passages are connected in a high rotational speed range. To be.
[0013]
As a result, it is only necessary to provide each of the three virtual surfaces with a structure that exhibits each variable intake action according to the low, medium, and high rotational speed ranges of the internal combustion engine. It can be easily formed. In particular, in a medium rotational speed region of an internal combustion engine, a pair of intake passages having one end connected to each cylinder in a cylinder group in which intake strokes are not continuous with each other are communicated with each other. Since they are adjacent to each other, it is only necessary to delete the partition wall between them, and the structure of the communication path can be formed very easily.
[0014]
Further, the virtual three planes are switched in three stages in the circumferential direction in accordance with the rotational speed of the internal combustion engine, and the rotary valve operates as described above. Therefore, in the low rotational speed range of the internal combustion engine, the intake collecting chamber is Acts as an atmosphere opening part, which becomes the reversal chamber of the intake pressure vibration, and is based on the intake pressure vibration of the low natural frequency and the low rotation of the engine in each long independent intake passage from the combustion chamber to the intake manifold In synchronism with the long open / close cycle of the intake valve, a high inertial supercharging effect is obtained, high intake charging efficiency is obtained for all the cylinders, and the output torque can be improved.
[0015]
Further, in the middle rotational speed region, the intake passage portion on the upstream side of the communication portion between a pair of adjacent intake passages, one end of which is connected to each cylinder in the cylinder group in which the intake strokes are not continuous, is in each cylinder group. The resonance pressure system is configured so that the intake pressure wave can be propagated to the next intake stroke of other cylinders in the same cylinder group without reversing the intake pressure wave in each intake passage and the intake communication portion. Resonance supercharging effect is obtained, high intake charging efficiency is obtained for each cylinder in the cylinder group in which the intake stroke is not continuous with each other, output torque can be improved, and between the low rotation speed range and the high rotation speed range It is possible to make up for the valley where the intake air charging efficiency and the output torque are reduced.
[0016]
Further, in the high rotational speed region, the communication portion (communication chamber) between all the adjacent intake passages acts as an air release portion, which becomes an inversion chamber of the intake pressure vibration, from the combustion chamber to the communication portion. A high inertial charging effect is achieved by synchronizing the intake pressure oscillation with high natural frequency in the short intake passage and the short opening and closing cycle of the intake valve based on the high engine speed, and high intake charging efficiency for all cylinders Thus, the output torque can be improved.
In this way, high intake charging efficiency and high output torque can be obtained over a wide rotational speed range from a low rotational speed range to a high rotational speed range.
[0017]
Furthermore, by configuring the invention according to claim 1 as described in claim 3, the rotary valve has four mutually independent passages and three communication chambers that are opened outward. The four mutually independent passages span between two vertices of an equilateral triangle obtained by dividing the outer periphery of the rotary valve into three equal intervals in the circumferential direction, and extend over the parallel length of four mutually independent intake passages. A first partition wall having a length, and three second partition walls that are connected to the first partition wall and block between adjacent intake passages; Two of them are spanning between the remaining vertex of the equilateral triangle and one edge of the first partition wall or a point in the vicinity of the edge, and the parallel lengths of four independent intake passages. A third partition wall having a length extending to at least the third partition wall Each of the three communication chambers includes a fourth partition wall and a fourth partition wall that blocks between the two adjacent intake passages. The remaining one of the three communication chambers includes the four independent passages. And a space excluding two of the three communication chambers.
[0018]
As a result, the rotary valve is switched in three stages at equal intervals according to the rotational speed of the internal combustion engine, and one end is connected to each cylinder in the cylinder group where the adjacent intake passages or the intake strokes are not continuous with each other. The internal structure of the rotary valve capable of communicating or blocking between a pair of adjacent intake passages is divided into four independent passages and three communication spaces by dividing the interior of the rotary valve by first to fourth partition walls. It can be obtained by a relatively simple method of forming a chamber.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the invention described in claims 1 to 8 of the present application illustrated in FIGS. 1 to 8 will be described.
FIG. 1 is a schematic perspective view of a variable intake device for an in-line four-cylinder internal combustion engine according to the present embodiment viewed virtually by cutting the upper half of the intake passage portion along the intake passage. FIG. 2 is a cross-sectional view of the variable intake device of FIG. 1, and shows the intake passage in its entirety. FIG. 3 is a view similar to FIG. 1, and shows the rotational state of the rotary valve and the intake air flow state when the internal combustion engine is in the middle rotational speed range, and FIG. 2 is a cross-sectional view of the variable intake device of FIG. 3, FIG. 5 is a view similar to FIG. 1, and the rotational state of the rotary valve when the internal combustion engine is in a high rotational speed range And FIG. 6 is a view similar to FIG. Cross-sectional view of the variable intake apparatus, FIG. 7, FIG, 8 for explaining the operation of the variable intake apparatus of FIG. 1 is a characteristic diagram of the variable intake apparatus of FIG. In the following, the cylinder arrangement direction is the left-right direction, and the left side in FIG. 1 is the left side.
[0020]
1 and 2, the variable intake device 1 for an in-line four-cylinder internal combustion engine according to the present embodiment has one end communicating with each cylinder of first to fourth cylinders # 1 to # 4 (not shown) of the internal combustion engine. Four mutually independent first to fourth intake passages 4 connected and connected to the single intake manifold 5 at the other end. ₁ ~ 4 _Four Is provided.
[0021]
The first to fourth cylinders # 1 to # 4 are ignited in the order of the first cylinder # 1, the third cylinder # 3, the fourth cylinder # 4, and the second cylinder # 2. Therefore, the intake stroke in each cylinder is also in this order, and the cylinder group consisting of the first and fourth cylinders # 1 and # 4 and the cylinder group consisting of the second and third cylinders # 2 and # 3 are in the intake stroke. Are cylinder groups that are not continuous with each other.
[0022]
First to fourth intake passages 4 ₁ ~ 4 _Four Is a crossing portion in the vicinity of a portion where one end of each cylinder # 1 to # 4 is connected in communication (in FIG. 1, the fourth intake passage 4 _Four The upper curved portion of the second and third intake passages 4 is ₂ 4 _Three The first and fourth intake passages 4 for each of the cylinder groups # 1, # 4, # 2, and # 3 in which the intake strokes are not continuous with each other (except for the portion that intersects the upper curved portion). ₁ 4 _Four And the second and third intake passages 4 ₂ 4 _Three Are arranged in parallel and in series with the cylinder arrangement direction. Therefore, the first and fourth intake passages 4 ₁ 4 _Four Are adjacent to each other in the left half of the cylinder arrangement direction, and the second and third intake passages 4 ₂ 4 _Three Are adjacent to each other in the right half of the cylinder arrangement direction.
[0023]
As a result, a pair of adjacent intake passages, one end of which is connected to each cylinder in the cylinder group in which the intake strokes are not continuous, are connected to each cylinder in the cylinder group including the first and fourth cylinders # 1 and # 4. A pair of adjacent first and fourth intake passages 4 whose one ends are in communication with each other ₁ 4 _Four And a pair of adjacent second and third intake passages 4 each having one end communicating with each cylinder in the cylinder group including the second and third cylinders # 2 and # 3. ₂ 4 _Three It is.
[0024]
First to fourth intake passages 4 ₁ ~ 4 _Four 2, is formed in a curved shape so as to be rolled up inside as shown in FIG. 2, and an intake air collecting chamber 5 is connected to the tip thereof. The intake air collecting chamber 5 has an intake duct 6 provided adjacent to the intake air collecting chamber 5 and the first to fourth intake passages 4. ₁ ~ 4 _Four The variable intake device 1 can be made compact by being held in the curved internal space.
[0025]
The intake air introduced to the intake duct 6 through an air cleaner and a throttle body (not shown) then flows into the intake air collecting chamber 5 having a relatively large volume and is collected there. Then, when the rotational speed of the internal combustion engine is in the low / medium rotational speed range, the first to fourth intake passages 4 are further started from here. ₁ ~ 4 _Four And then flows through these relatively long passages and is sucked into each of the first to fourth cylinders # 1 to # 4. Although not shown, the communication path between the intake duct 6 and the intake manifold 5 is provided at the center of the intake manifold 5 in the longitudinal direction. 1st to 4th intake passage 4 leading to 4 ₁ ~ 4 _Four The intake passage length including the same is made equal.
[0026]
First to fourth intake passages 4 ₁ ~ 4 _Four The bottom wall in the middle of each of the first to fourth openings 7 having a substantially rectangular shape in front view. ₁ ~ 7 _Four These first to fourth openings 7 are formed. ₁ ~ 7 _Four To a part of the first to fourth intake passages 4 ₁ ~ 4 _Four A single rotary valve 3 is provided so as to protrude from each of the two. The first to fourth intake passages 4 of the rotary valve 3 ₁ ~ 4 _Four When the rotary valve 3 is viewed from the side in the axial direction, the projecting portion corresponds to a crescent-shaped portion that is cut out by approximately 1/3 arc length (see FIG. 2).
[0027]
The rotary valve 3 includes first to fourth intake passages 4. ₁ ~ 4 _Four The remaining portions excluding the approximately 1/3 arc portion protruding in the side view are held by the main body wall portion 8 of the intake manifold 2 and arranged. The main body wall portion 8 has a substantially arc shape that is 2/3 in a side view, and can close first and second communication chambers 10 and 12 (to be described later) of the rotary valve 3 according to the rotational position of the rotary valve 3. it can. Almost half of the main body wall portion 8 forms a part of the wall of the intake air collecting chamber 5.
[0028]
Next, the structure, operation, and effect of the rotary valve 3 will be described in detail.
As shown in FIG. 2, the rotary valve 3 has virtual three surfaces a, b, and c that are partitioned at equal intervals in the circumferential direction when viewed from the side in the axial direction. By switching the surfaces a, b and c in three stages in the circumferential direction according to the rotational speed of the internal combustion engine, as will be described in detail below, adjacent intake passages 4 ₁ And 4 _Four 4 _Four And 4 ₂ 4 ₂ And 4 _Three A pair of adjacent first and fourth intake passages 4 each having one end communicating with each cylinder in a cylinder group in which the intervals or the intake strokes are not continuous with each other ₁ 4 _Four Between the second and third intake passages 4 ₂ 4 _Three It can be communicated or blocked.
[0029]
One surface a side of the virtual three surfaces a, b, c of the rotary valve 3 is adjacent to the intake passage 4 as shown in FIGS. 5 and 6. ₁ And 4 _Four 4 _Four And 4 ₂ 4 ₂ And 4 _Three The first communication chamber 10 having a large volume capable of communicating with each other is provided.
[0030]
The first communication chamber 10 has a partition wall (third partition wall) 14 that partitions the first surface a side and the other one surface b side over the entire length of the rotary valve 3, the first surface a side, and the other one surface b. Is formed in a shape that is recessed inward of the rotary valve 3 by being sandwiched by a partition wall (first partition wall) 15 that divides the side and the other surface c side over the entire length of the rotary valve 3. , First to fourth intake passages 4 ₁ ~ 4 _Four Each having a cross-sectional area larger than the cross-sectional area of the second communication chamber 12 described later, and the first to fourth intake passages 4. ₁ ~ 4 _Four All of these intake passages are communicated while abruptly changing the cross-sectional shape of each of the above.
[0031]
As shown in FIGS. 3 and 4, the other one side b of the virtual three surfaces a, b, and c of the rotary valve 3 has cylinder groups # 1, # 4, and # in which the intake strokes are not continuous with each other. 2 and # 3, a pair of adjacent first and fourth intake passages 4 whose one ends are connected to the respective cylinders in # 3 and # 3. ₁ 4 _Four , A pair of adjacent second and third intake passages 4 ₂ 4 _Three 12 communication rooms that can communicate with each other ₁ , Communication room 12 ₂ have. These two communication rooms 12 ₁ , 12 ₂ Are collectively referred to as a second communication chamber 12.
[0032]
Communication room 12 which is one of the second communication rooms 12 ₁ The other one, the communication room 12 ₂ Are a partition wall (third partition wall) 14, a partition wall (first partition wall) 15, and two central fourth and second intake passages 4. _Four 4 ₂ It is formed by being surrounded by a partition wall (fourth partition wall) 16 for partitioning. The partition wall (third partition wall) 14 has a communication chamber 12 ₁ , 12 ₂ Is the cross-sectional area of each intake passage 4 ₁ ~ 4 _Four The rotary valve 3 is formed in a shape recessed inward so as to be substantially equal to the cross-sectional area of the rotary valve 3.
[0033]
These first communication chamber 10 and second communication chamber 12 (12 ₁ , 12 ₂ ) Are simultaneously closed by the body wall portion 8 of the intake manifold 2 when the rotary valve 3 is in the rotational position shown in FIGS.
[0034]
As shown in FIGS. 1 and 2, the other one surface c side of the virtual three surfaces a, b, c of the rotary valve 3 is adjacent to the intake passage 4. ₁ And 4 _Four 4 _Four And 4 ₂ 4 ₂ And 4 _Three It has the partition wall which interrupts | blocks each. This partition wall is composed of crescent-shaped partition walls (1 to 3 of the second partition wall) 17 to 19 that partition these intake passages, respectively, and the aforementioned partition wall (first partition wall) 15. Yes. When the rotary valve 3 is in the rotational position shown in FIGS. 1 and 2, the adjacent intake passage 4 ₁ And 4 _Four 4 _Four And 4 ₂ 4 ₂ And 4 _Three A long and independent intake passage 4 that is completely independent from each other. ₁ ~ 4 _Four Providing four independent passage portions.
[0035]
This partition wall 15 is connected to each intake passage 4 ₁ ~ 4 _Four In order not to change the cross-sectional shape along the passage length direction, the air intake passage 4 is curved so as to protrude into each passage. ₁ ~ 4 _Four In order not to change the cross-sectional shape along the direction orthogonal to the passage length direction, the curved portion is formed so as to be slightly recessed inward of the rotary valve.
[0036]
First to fourth partition walls 14 to 19, first and second communication chambers 10 and 12 (12 ₁ , 12 ₂ ) Will be described in more detail.
The first partition wall 15 extends between two vertices of an equilateral triangle obtained by dividing the outer periphery of the rotary valve 3 into three parts at equal intervals in the circumferential direction, and four independent intake passages 4. ₁ ~ 4 _Four It has a length that extends to the parallel length of. The three second partition walls 17 to 19 are connected to the first partition wall 15, have a crescent shape, and are adjacent to the intake passage 4. ₁ And 4 _Four 4 _Four And 4 ₂ 4 ₂ And 4 _Three Block the gap. The third partition wall 14 spans between the remaining vertex of the equilateral triangle and a point near the edge of one of the first partition walls 15 (upper side in FIG. 2), and four independent intakes. Passage 4 ₁ ~ 4 _Four It has a length that extends to the parallel length of. The fourth partition wall 16 is connected to the third partition wall 14 and the first partition wall 15 on one end edge side of the first partition wall 15, and has two adjacent intake passages 4 in the center. _Four 4 ₂ Block the gap. First communication chamber 10 and second communication chamber 12 (12 ₁ , 12 ₂ Are arranged back to back with the third partition wall 14 as a boundary. The rotary valve 3 has three communication chambers 10 and 12 in total. ₁ , 12 ₂ Have
[0037]
The rotary valve 3 has any one of the virtual three surfaces a, b, c in the first to fourth intake passages 4. ₁ ~ 4 _Four First through fourth openings 7 ₁ ~ 7 _Four As shown, the control means is provided that can be switched in three stages at equal intervals according to the rotational speed of the internal combustion engine. An electric or negative pressure actuator (not shown) is used for this control means.
[0038]
These actuators are disposed in the intake device 1 on one end side of the rotary valve 3. The rotary valve 3 is sequentially operated step by step in accordance with the rotational speed of the internal combustion engine, and rotates in the forward direction and in the reverse direction in accordance with increase / decrease in the rotational speed of the internal combustion engine. In the case of an electric actuator, it is only necessary to operate the electric motor stepwise by a signal from the control means. In the case of a negative pressure actuator, a diaphragm having at least two negative pressure chambers is required, and a control valve is provided for each of them, and the negative pressure is introduced by sequentially operating the control valve according to the rotational speed of the internal combustion engine. The rotary valve 3 can be operated stepwise, and the control means performs introduction (instruction) of the negative pressure. The negative pressure is introduced from the downstream of the throttle valve and is distributed to each control valve via the negative pressure chamber.
[0039]
This control means switches the rotary valve 3 as follows according to the rotational speed of the internal combustion engine.
First, the control means is configured such that the rotational speed of the internal combustion engine is a predetermined rotational speed N. ₁ When there is a lower low speed range (N <N ₁ ), As shown in FIGS. 1 and 2, the other one surface c side of the virtual three surfaces a, b, c of the rotary valve 3 is the first to fourth intake passages 4. ₁ ~ 4 _Four First through fourth openings 7 ₁ ~ 7 _Four The rotary valve 3 is controlled so as to face Thereby, the adjacent intake passage 4 ₁ And 4 _Four 4 _Four And 4 ₂ 4 ₂ And 4 _Three The first to fourth intake passages 4 are long and completely separated by the partition wall 15 and the partition walls 17 to 19 and are completely independent. ₁ ~ 4 _Four Is formed.
[0040]
The intake air in the intake air collecting chamber 5 is supplied to these long first to fourth intake passages 4. ₁ ~ 4 _Four To each of these intake passages 4 ₁ ~ 4 _Four And supplied to each cylinder # 1 to # 4. At this time, the intake air collecting chamber 5 acts as an atmosphere opening portion, and this is an inversion chamber of the intake pressure vibration, and a long intake passage 4 from the combustion chamber to the intake air collecting chamber 5. ₁ ~ 4 _Four The intake pressure oscillation with a low natural frequency in the engine and the long open / close cycle of the intake valve based on the low engine rotation synchronize with each other to obtain a high inertial supercharging effect and high intake charging efficiency for all cylinders. Thus, the output torque can be improved (see (1) in FIGS. 7 and 8).
[0041]
Next, this control means is such that the rotational speed of the internal combustion engine is N ₁ Higher, the predetermined speed N ₂ (N ₁ <N ₂ ) In the lower middle rotation speed range (N ₁ <N <N ₂ 3), as shown in FIGS. 3 and 4, the other one surface b side of the virtual three surfaces a, b, c of the rotary valve 3 is the first to fourth intake passages 4. ₁ ~ 4 _Four First through fourth openings 7 ₁ ~ 7 _Four The rotary valve 3 is controlled so as to face As a result, a pair of first and fourth intake passages 4 whose one ends are connected to the respective cylinders in the cylinder groups # 1 and # 4 and the cylinder groups # 2 and # 3 whose intake strokes are not continuous with each other. ₁ 4 _Four Between the pair of second and third intake passages 4 ₂ 4 _Three Each room has 12 communication rooms ₁ , 12 ₂ It is communicated via.
[0042]
The pair of first and fourth intake passages 4 ₁ 4 _Four Between the pair of second and third intake passages 4 ₂ 4 _Three Each communication section (communication chamber 12 constituting the second communication chamber 12) ₁ , 12 ₂ ) Each intake passage section 4 on the upstream side _1u 4 _4u Set of and 4 _2u 4 _3u Constitute a resonance system of each cylinder group, and each intake passage 4 ₁ ~ 4 _Four And each intake communication section (communication chamber 12 ₁ , 12 ₂ ) The intake pressure wave can be propagated to the next intake stroke of other cylinders in the same cylinder group without reversing the intake pressure wave, and a high resonance supercharging effect is obtained, and the intake strokes are continuous with each other. High intake charging efficiency is obtained for each cylinder in the cylinder groups # 1, # 4 and # 2, # 3 which are not, and the output torque can be improved. In this way, it is possible to make up for a valley where the intake charging efficiency and the output torque between the low rotation speed region and the high rotation speed region decrease (see (2) in FIGS. 7 and 8).
[0043]
Next, the control means is configured such that the rotational speed of the internal combustion engine is N. ₂ When in a higher high speed range (N ₂ In <N), as shown in FIGS. 5 and 6, the first surface a side of the virtual three surfaces a, b, c of the rotary valve 3 is the first to fourth intake passages 4. ₁ ~ 4 _Four First through fourth openings 7 ₁ ~ 7 _Four The rotary valve 3 is controlled so as to face Thereby, the adjacent intake passage 4 ₁ And 4 _Four 4 _Four And 4 ₂ 4 ₂ And 4 _Three The first to fourth intake passages 4 are all connected to each other. ₁ ~ 4 _Four Are all in communication with each other.
[0044]
At this time, the first communication chamber 10 formed in a large volume has the first to fourth intake passages 4. ₁ ~ 4 _Four Since each of the cross-sectional shapes of the intake air is changed abruptly, this acts as an atmosphere opening portion, which becomes an inversion chamber of the intake pressure vibration, and a short intake passage portion 4 from the combustion chamber to the first communication chamber 10 _1d ~ 4 _4d The intake pressure vibration with a high natural frequency in the engine and the short opening / closing cycle of the intake valve based on the high engine speed are synchronized to provide a high inertial supercharging effect and high intake charging efficiency for all cylinders. Thus, the output torque can be improved (see (3) in FIGS. 7 and 8).
[0045]
In this way, a flat and high intake charging efficiency and a high output torque can be obtained over a wide rotational speed range from a low rotational speed range to a high rotational speed range of the internal combustion engine. In general, when inertial supercharging and resonance supercharging are compared, the effect is greater in inertial supercharging, and resonance supercharging is positioned as an effect that compensates for inertial supercharging. The valley between the high intake charging efficiency based on the inertial supercharging effect obtained in the low rotational speed range and the high intake charging efficiency based on the inertial supercharging effect obtained in the high rotational speed range is in the middle rotational speed range. This is fully compensated for by improving the intake charging efficiency based on the obtained resonance supercharging effect. The intake air is always supplied from the intake manifold 5 to the cylinders # 1 to # 4 over the entire rotational speed range of the internal combustion engine.
[0046]
Since the present embodiment is configured as described above, the following effects can be further achieved.
Four mutually independent first to fourth intake passages 4 having one end connected to each cylinder of the in-line four-cylinder internal combustion engine and the other end connected to a single intake manifold 5. ₁ ~ 4 _Four However, the cylinders are arranged in series in parallel to the cylinder arrangement direction for each cylinder group in which the intake strokes are not continuous with each other, except for the intersection near the portion where one end is connected to each cylinder. And these intake passages 4 ₁ ~ 4 _Four The rotary valve 3 is provided in such a way that approximately 1/3 arc length of the outer circumference protrudes.
[0047]
As a result, the first to fourth intake passages 4 ₁ ~ 4 _Four Does not cross each other except for an intersection near the portion where one end of each cylinder is connected in communication, and the rotary valve 3 that performs variable intake does not protrude in the length direction. The variable intake device 1 including the manifold 2 can be formed compactly, particularly in the cylinder arrangement direction, and space efficiency is good. In addition, each intake passage 4 ₁ ~ 4 _Four It is easy to achieve the same length.
[0048]
Further, high intake charging efficiency and high output torque over a wide rotational speed range from the low rotational speed range to the high rotational speed range are the first to fourth intake passages 4. ₁ ~ 4 _Four Since the rotary valve 3 provided so that approximately 1/3 arc length of the outer circumference protrudes in the middle of the engine is switched and controlled in three stages at equal intervals according to the rotational speed of the internal combustion engine. The number of such parts can be reduced, contributing to cost reduction, simplification of the structure, weight reduction, etc., and the variable intake device 1 for a four-cylinder internal combustion engine that does not require space can be easily obtained. Further, the rotary valve 3 has a valve body and a shaft portion whose first to fourth intake passages 4 are arranged. ₁ ~ 4 _Four Since it does not protrude inward, the intake resistance is not increased.
[0049]
Further, since the rotary valve 3 is switched by an electric or negative pressure actuator, the configuration of control means for switching the rotary valve 3 in three steps at equal intervals according to the rotational speed of the internal combustion engine becomes easy.
[0050]
Further, the rotary valve 3 has virtual three surfaces a, b, and c that are partitioned at equal intervals in the circumferential direction as viewed from the side in the axial direction on the outer periphery. It is switched in three stages in the circumferential direction according to the rotational speed of the internal combustion engine, and all adjacent intake passages 4 in the low rotational speed range of the internal combustion engine. ₁ And 4 _Four 4 _Four And 4 ₂ 4 ₂ And 4 _Three A pair of adjacent first and fourth intake passages 4 having one end connected to each cylinder in the cylinder group in which the intake strokes are not continuous with each other in the middle rotational speed region. ₁ 4 _Four Between the pair of second and third intake passages 4 ₂ 4 _Three All adjacent intake passages 4 that communicate with each other at high rotational speeds ₁ And 4 _Four 4 _Four And 4 ₂ 4 ₂ And 4 _Three It is made to communicate between them.
[0051]
As a result, it is only necessary to provide each of the virtual three surfaces a, b, and c with a structure that exhibits each variable intake action according to the low, medium, and high rotational speed regions of the internal combustion engine. The internal structure can be formed relatively easily. In particular, a pair of first and fourth intake passages 4 each having one end communicating with each cylinder in a group of cylinders in which the intake strokes are not continuous with each other in the middle rotational speed region of the internal combustion engine. ₁ 4 _Four Between the pair of second and third intake passages 4 ₂ 4 _Three In order to communicate with each other, the intake passages in each of these pairs are adjacent to each other. Therefore, it is only necessary to delete the partition wall between them, and the communication passage (second communication chamber 12 (12 ₁ , 12 ₂ )) Structure can be formed very easily.
[0052]
Also, the first to fourth intake passages 4 ₁ ~ 4 _Four Is bent so as to be wound inside, and the intake air collecting chamber 5 and the intake duct 6 are arranged in the curved inner space, and the rotary valve 3 is partly held by the wall of the air intake collecting chamber 3. Since the variable intake device 1 is arranged in a round shape when viewed from the side, the variable intake device 1 can be formed more compactly, and the space efficiency is further improved.
[0053]
The first communication chamber 10 and the second communication chamber 12 (12 ₁ , 12 ₂ ), The structure of the partition walls 14 and 15 is not limited to that illustrated in the present embodiment, and various modifications are possible.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a variable intake device for an in-line four-cylinder internal combustion engine according to the present embodiment viewed virtually by cutting the upper half of the intake passage portion along the intake passage. It is the figure which showed together the rotation state of the rotary valve when it exists in a rotation speed area, and the flow state of intake air.
2 is a cross-sectional view of the variable intake device of FIG. 1. FIG.
FIG. 3 is a view similar to FIG. 1 and also shows the rotational state of the rotary valve and the intake air flow state when the internal combustion engine is in the middle rotational speed range.
4 is a cross-sectional view of the variable intake device of FIG. 3, similar to FIG.
FIG. 5 is a view similar to FIG. 1 and also shows a rotational state of the rotary valve and an intake air flow state when the internal combustion engine is in a high rotational speed range.
6 is a view similar to FIG. 2 and a cross-sectional view of the variable intake device of FIG.
FIG. 7 is a view for explaining the operation of the variable intake device of the in-line four-cylinder internal combustion engine in the present embodiment.
FIG. 8 is a characteristic diagram of a variable intake device for an in-line four-cylinder internal combustion engine in the present embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Variable intake device, 2 ... Intake manifold, 3 ... Rotary valve, 4 ₁ ~ 4 _Four ... First to fourth intake passages, 4 _1u ~ 4 _4u ... Upstream side intake passage part, 4 _1d ~ 4 _4d ... downstream side intake passage part, 5 ... intake manifold, 6 ... intake duct, 7 ₁ ~ 7 _Four ... 1st-4th opening, 8 ... Main part wall part, 10 ... 1st communication chamber, 12 (12 ₁ , 12 ₂ ) ... second communication chamber, 14 ... third partition wall, 15 ... first partition wall, 16 ... fourth partition wall, 17-19 ... three second partition walls, ac ... virtual 3 surface.

Claims

Four independent intake passages, one end of which is connected to each cylinder of the in-line four-cylinder internal combustion engine and the other end of which is connected to a single intake manifold, and one end of which is connected to each cylinder. Are arranged in series in parallel with the cylinder arrangement direction for each cylinder group in which the intake strokes are not continuous with each other, except for the intersecting portion in the vicinity of
The intake air collecting chamber is disposed in the curved internal space of the intake passage,
A rotary valve is provided so that an approximately 1/3 arc length of the outer periphery protrudes in the middle of the intake passage, and at least the remaining part of the outer periphery is held by the wall of the intake air collecting chamber.
The rotary valve is switched in three stages at equal intervals according to the rotational speed of the internal combustion engine, and one end thereof is connected to each cylinder in a cylinder group where all adjacent intake passages or intake strokes are not continuous with each other. A variable intake device for an in-line four-cylinder internal combustion engine, wherein a pair of adjacent intake passages adjacent to each other can be communicated or blocked.

The rotary valve has, on its outer periphery, three virtual surfaces that are partitioned at equal intervals in the circumferential direction as viewed from the axial direction, and the virtual three surfaces are arranged in the circumferential direction according to the rotational speed of the internal combustion engine. It is switched to 3 stages
In the low rotational speed range of the internal combustion engine, shuts off all adjacent intake passages,
Communicating between a pair of adjacent intake passages each having one end connected to each cylinder in a group of cylinders in which the intake strokes are not continuous with each other in a middle rotational speed range;
2. A variable intake system for an in-line four-cylinder internal combustion engine according to claim 1, wherein all adjacent intake passages communicate with each other in a high rotational speed range.

The rotary valve has four independent passages and three communication chambers, each of which opens outward.
The four mutually independent passages span between two vertices of an equilateral triangle obtained by dividing the outer periphery of the rotary valve into three equal intervals in the circumferential direction, and are parallel to the length of the four independent intake passages. Partitioned by a first partition wall having a length that extends and three second partition walls that are connected to the first partition wall and block between adjacent intake passages,
Two of the three communication chambers span between the remaining vertex of the equilateral triangle and one end edge of the first partition wall or a point near the end edge, and A third partition wall having a length that extends over the length of the independent intake passages, and a fourth partition wall that is connected to at least the third partition wall and blocks between the two adjacent intake passages. And each compartment is formed,
The remaining one of the three communication chambers is formed by a space excluding the four independent passages and two of the three communication chambers. A variable intake system for an in-line four-cylinder internal combustion engine.