JP4530578B2

JP4530578B2 - Multi-cylinder engine intake system

Info

Publication number: JP4530578B2
Application number: JP2001145366A
Authority: JP
Inventors: 孝松本; 政彦菊地; 智典井熊; 哲和田
Original assignee: Honda Motor Co Ltd; Keihin Corp
Current assignee: Honda Motor Co Ltd; Keihin Corp
Priority date: 2001-05-15
Filing date: 2001-05-15
Publication date: 2010-08-25
Anticipated expiration: 2021-05-15
Also published as: JP2002339756A

Description

【０００１】
【発明の属する技術分野】
本発明は，第１及び第２バンクを有するエンジンの一側に配設される吸気分配箱の一端部に，スロットルボディの吸気道に連なる吸気入口を設け，また前記吸気分配箱内を隔壁により，前記吸気入口にそれぞれ連通する第１及び第２分配室に区画すると共に，該隔壁に，第１及び第２分配室間を連通，遮断し得る開閉弁を設け，前記前記第１及び第２分配室にそれぞれ開口すると共に，前記第１及び第２のバンクの吸気ポートにそれぞれ連なる第１及び第２吸気分岐管を前記吸気分配箱に連設し，エンジンの運転状態に応じて前記開閉弁を開閉することにより吸気特性を変えて，エンジンの低速から高速に渡る広い運転域で高出力性能を発揮し得るようにした，多気筒エンジンの吸気装置の改良に関する。
【０００２】
【従来の技術】
かゝる多気筒エンジンの吸気装置は，例えば特開平９−８８７４６号公報に開示されているように，既に知られている。
【０００３】
【発明が解決しようとする課題】
ところで，上記公報に開示されている吸気装置では，開閉弁を軸支すると共に，この開閉弁により開閉される弁孔を有する隔壁体が，分配箱本体と吸気マニホールドとの間に介裝される構成となっているので，開閉弁のメンテナンスに際しては，分配箱本体及び吸気マニホールド間を分解するという面倒な作業が必要となるため，メンテナンス性が良好とは言えない。
【０００４】
本発明は，かゝる事情に鑑みてなされたもので，吸気分配箱から，その外側の蓋体を取り外すだけで開閉弁のメンテナンスを行うことができ，しかも開閉弁の安定した作動を確保することができるようにした，前記多気筒エンジンの吸気装置を提供することを目的とする。
【０００５】
【課題を解決するための手段】
上記目的を達成するために，本発明は，第１及び第２バンクを有するエンジンの一側に配設される吸気分配箱の一端部に，スロットルボディの吸気道に連なる吸気入口を設け，また前記吸気分配箱内を隔壁により，前記吸気入口にそれぞれ連通する第１及び第２分配室に区画すると共に，該隔壁に，第１及び第２分配室間を連通，遮断し得る開閉弁を設け，前記前記第１及び第２分配室にそれぞれ開口すると共に，前記第１及び第２のバンクの吸気ポートにそれぞれ連なる第１及び第２吸気分岐管を前記吸気分配箱に連設した，多気筒エンジンの吸気装置において，前記吸気入口，前記第１及び第２吸気分岐管並びに前記隔壁の一半部を有すると共に，前記第１及び第２分配室間に渡る開口部を前記第１及び第２分岐管と反対側の外側壁に設けた分配箱本体と，前記隔壁の他半部を有すると共に，前記開口部を囲繞しながら前記分配箱本体の外側面に着脱可能に接合されるループ状の囲い壁を内側面に一体に突設した軽合金鋳造製の蓋体とで前記吸気分配箱を構成し，前記他半部には，前記第１及び第２分配室間を連通する弁孔と，この弁孔を開閉する開閉弁の弁軸を支承する軸受孔とを設け，前記弁孔を拡大すべく前記蓋体の，前記弁孔に対応する部分に外方膨出部を形成し，クランク軸を縦置きにした船外機用エンジンの後向きにした第１及び第２バンクの頭部と，このエンジンを覆う船外機用エンジンフードの後壁との間に前記吸気分配箱を上下に長く配置し，該吸気分配箱の上端部に前記吸気入口を設ける一方，該吸気分配箱の下端部に，前記弁軸を介して前記開閉弁を駆動するアクチュエータを取り付けたことを第１の特徴とする。
【０００６】
この第１の特徴によれば，蓋体及び開閉弁で１個の組立体を構成することになるから，蓋体を分配箱本体から取り外すことにより，開閉弁及びその周辺のメンテナンスを容易に行うことができ，メンテナンス性の向上に寄与し得る。
【０００７】
しかも軽合金鋳造製の蓋体は，吸気分配箱の軽量化に寄与すると共に，周囲の温度変化に影響されずに所定形状を維持し得る上，内面の囲い壁により効果的に補強されるため，蓋体と一体の隔壁他半部に穿設された，弁軸の軸受孔に変形を来すことがなく，開閉弁の安定した作動を確保することができる。さらに蓋体内面の囲い壁は，蓋体の鋳造時の湯路を拡大する役目をも果たし，蓋体の鋳造性を高めるので，品質の向上にも寄与する。
【０００８】
また蓋体の，弁孔に対応する部分に形成された外方膨出部により，その部分の隔壁他半部の高さの増加を得て，開口面積の大なる弁孔の形成が可能となるのみならず，その外方膨出部により吸気分配箱の容積増加を図ることをできる。
【０００９】
特に，弁孔を有する蓋体は，吸入分岐管と一体の分配箱本体に比して小型且つ形状が単純であるから，高圧ダイカスト等の精密鋳造が可能となる。したがって，弁孔の後加工が不要で，しかも高剛性で，且つ周囲の温度変化によっても歪みを生ずることがない高品質の蓋体が容易に得られと共に，それに軸支される開閉弁の良好な開閉作動を，周囲温度の変化に関係なく常に確保することができる。
【００１０】
さらに船外機において，吸気入口とアクチュエータとの干渉を回避しながら，エンジンの第１及び第２バンクとエンジンフードとの間の狭小なスペースに吸気装置をコンパクトに収容することができる。
【００１１】
また本発明は，第１の特徴に加えて，前記吸気分配箱の，前記第１及び第２バンク間の谷間に臨む前壁に前記第１及び第２分岐管を，これらが該吸気分配箱内に配置されるようにして一体に成形したことを第２の特徴とする。
【００１２】
【発明の実施の形態】
本発明の実施例の形態を，添付図面に示す本発明の一実施例に基づいて以下にに説明する。
【００１３】
図１は船外機の全体側面図，図２は図１の要部縦断面図，図３は図２の３−３線断面図，図４は図２の４−４線断面図，図５は図４の５−５線断面図，図６は図５の６−６線断面図，図７は図５の７−７線断面図，図８は図５に対応した吸気マニホールドの要部分解図，図９は図８の９−９線断面図，図１０は図９の１０部拡大図，図１１は図８の１１矢視図，図１２は図１１の１２−１２線断面図，図１３は図１１の１３−１３線断面図である。
【００１４】
尚，以下の説明において，前後左右とは，船外機Ｏが取り付けられる船体Ｈを基準にして言うものとする。
【００１５】
図１〜図３において，船体Ｈの後端に取り付けられる船外機Ｏは，マウントケース１，このマウントケース１の下端面に結合されるエクステンションケース２，及びこのエクステンションケース２の下端面に結合されるギヤケース３を備えており，マウントケース１の上端面にＶ型６気筒水冷式４ストロークエンジンＥがクランク軸４を縦置きにして搭載される。
【００１６】
またマウントケース１には，ステー１３を介して環状のアンダカバー１４が固着される。このアンダカバー１４は，エンジンＥの下部からエクステンションケース２の上部までの区間の周囲を覆うもので，その上端に，エンジンＥを上方から覆うエンジンフード１２が着脱可能に取り付けられる。このエンジンフード１２及びアンダカバー１４とにより，エンジンＥを収容するエンジンルーム１５が画成される。
【００１７】
エンジンＥは，縦置きのクランク軸４を支持するクランクケース５と，このクランクケース５から後方に向かってＶ字状に広がる左右一対のバンク６Ｌ，６Ｒとを有しており，クランクケース２５の下面が前記マウントケース１の上部取り付け面にボルト結合される。
【００１８】
図５及び図６に示すように，各バンク６Ｌ，６Ｒは，上下に配列する複数本（図示例では３本）のシリンダボア７Ｌ，７Ｒを備える。また左右のバンク６Ｌ，６Ｒは，クランクケース２５の後端面にボルト結合され，上記左右のシリンダボア７Ｌ，７Ｒを有するシリンダブロック７と，このシリンダブロック７の，シリンダボア７Ｌ，７Ｒがそれぞれ開口する左右の後端面にボルト結合される一対のシリンダヘッド９Ｌ，９Ｒと，これらシリンダヘッド９Ｌ，９Ｒに形成される動弁室を閉じるべく，シリンダヘッド９Ｌ，９Ｒの後端面に結合される一対のヘッドカバー１０Ｌ，１０Ｒとから構成される。
【００１９】
図２〜図４において，エンジンフード１２の後面上部に空気取り入れ口１６が設けられ，この空気取り入れ口１６に連通して，下端をエンジンルーム１５の下部に開放する偏平な通風ダクト１７がエンジンフード１２の後壁内面に沿って配設される。この通風ダクト１７によりエンジンルーム１５に取り入れられた空気は，吸気サイレンサ１８及び吸気マニホールドＭｉを通して左右のバンク６Ｌ，６Ｒに吸気される。
【００２０】
吸気サイレンサ１８はエンジンＥの上面に取り付けられるもので，箱型をなしており，左右一対の入口２０，２０と，これら入口２０，２０の間に配置される出口２１とを備える。その出口２１にスロットルボディ２２の吸気道２２ａの上流端が接続される。その吸気道２２ａには，船体Ｈに設けられるアクセルレバー（図示せず）に連動するスロットル弁２３が軸支される。
【００２１】
図５〜図７において，前記スロットルボディ２２の吸気道２２ａの下流端に連なる吸気マニホールドＭｉは，左右のバンク６Ｌ，６Ｒ間の谷間２４に臨んで配設される。また上記谷間２４には，左バンク６Ｌのシリンダヘッド９Ｌが有する複数の吸気ポート２５Ｌに接続する複数の左吸気管２６Ｌと，右バンク６Ｒのシリンダヘッド９Ｒに形成された複数の吸気ポート２５Ｒに接続する複数の右吸気管２６Ｒとが，各上流端を後方へ向けるようにして配設される。複数の左吸気管２６Ｌの上流端には，これらを相互に連結する左連結フランジ２７Ｌが一体に形成され，複数の右吸気管２６Ｒの上流端には，これらを相互に連結する右連結フランジ２７Ｒが一体に形成される。左右のバンク６Ｌ，６Ｒの吸気管２６Ｌ，２６Ｒに，対応するバンク６Ｌ，６Ｒの吸気弁に向かって燃料を噴射する電磁式の燃料噴射弁２８Ｌ，２８Ｒが取り付けられる。
【００２２】
吸気マニホールドＭｉは，上下方向に長く且つ前後方向に偏平な形状を持つ吸気分配箱３０を備え，これは左右のバンク６Ｌ，６Ｒの両後面を跨ぐように配置される。この吸気分配箱３０の前壁上部には，中心部に吸気入口３１を有する連結フランジ３２が形成され，これに前記スロットルボディ２２の下流端に形成した連結フランジ３３が結合される。
【００２３】
吸気分配箱３０内には上下方向に延びる隔壁３５が設けられ，これによって吸気分配箱３０の内部は，それぞれ吸気入口３１に連通する左分配室３７Ｌ及び右分配室３７Ｒに区画される。隔壁３５には，吸気入口３１に流入した空気を左右の分配室３７Ｌ，３７Ｒに分流させる誘導壁３６が連設される。
【００２４】
また吸気分配箱３０の前記谷間２４に臨む前壁には，左右の分配室３７Ｌ，３７Ｒにそれぞれ連通する複数の左吸気分岐管３８Ｌ及び右吸気分岐管３８Ｒが吸気分配箱３０内に配置されるように一体に成形される。左右の複数の吸気分岐管３８Ｌ，３８Ｒの下流端には，これらを相互に連結する１個の連結フランジ３９一体に成形され，これが前記左右の吸気管２６Ｌ，２６Ｒの連結フランジ２７Ｌ，２７Ｒにボルト結合される。
【００２５】
吸気分配箱３０の内部を左右の分配室３７Ｌ，３７Ｒに区画する前記隔壁３５には，両分配室３７Ｌ，３７Ｒ間を直接連通する上下一対の弁孔４０が設けられ，この弁孔４０を開閉する一対のバタフライ型の開閉弁４１が軸支される。
【００２６】
而して，エンジンＥの運転中，吸気サイレンサ１８の左右の入口２０，２０に流入した空気は，吸気サイレンサ１８内で合流し，出口２１を出て，スロットルボディ２２の吸気道２２ａを通り，吸気マニホールドＭｉの吸気分配箱３０の吸気入口３１に向かう。その際，吸気道２２ａでは，スロットル弁２３の開度により，エンジンＥの吸気量が制御される。
【００２７】
エンジンＥの低速運転域では，吸気分配箱３０内の開閉弁４１は閉じておくものであって，吸気マニホールドＭｉの吸気入口３１に流入した空気は，上下に延びる左右の分配室３７Ｌ，３７Ｒに分流する。そして，左分配室３７Ｌに分流した空気は，複数の左吸気分岐管３８Ｌに更に分流し，左吸気管２６Ｌを経て左バンク６Ｌの吸気ポート２５Ｌを通り，対応するシリンダボア２７Ｌに吸気される。また右分配室３７Ｒに分流した空気は，複数の右吸気分岐管３８Ｒに更に分流し，右吸気管２６Ｒを経て右バンク６Ｒの吸気ポート２５Ｒを通り，対応するシリンダボア２７Ｒに吸気される。
【００２８】
ところで，エンジンＥの低速運転域では，左右の吸気分岐管３８Ｌ，３８Ｒの上流端が開口する左分配室３７Ｌ及び右分配室３７Ｒは，上部の吸気入口３１との連通部を除いて，閉じ状態の開閉弁４１により遮断されているから，左分配室３７Ｌから左バンク６Ｌの吸気ポート２５Ｌに至る吸気系と，右分配室３７Ｒから右バンク６Ｒの吸気ポート２５Ｒに至る吸気系とよりなる，互いに吸気干渉の生じない２系統の共鳴過給吸気系が構成され，しかもその各共鳴過給吸気系の固有振動がエンジンＥの低速運転域での各バンク６Ｌ，６Ｒの吸気弁の開閉周期と略一致するように設定されており，したがって共鳴過給効果が有効に発揮され，エンジンの低速運転域での吸気充填効率が増大し，出力性能の向上を図ることができる。
【００２９】
また，エンジンＥの高速運転域では，吸気分配箱３０内の開閉弁４１は開くものであって，これにより左右の分配室３７Ｌ，３７Ｒは弁孔４０を介して相互に連通して大容量の１個のサージタンクを構成し，このサージタンクに左右の吸気分岐管３８Ｌ，３８Ｒの上流端が開口するので，各バンク６Ｌ，６Ｒにおける吸気慣性の容量が増大し，共鳴吸気系の実質的な長さが減少して，該共鳴吸気系の固有振動数がエンジンＥの高速運転域での各バンク６Ｌ，６Ｒの吸気弁の開閉周期と一致するように高まり，共鳴過給効果が有効に発揮されて，エンジンＥの高速運転域での吸気充填効率が増大し，出力性能の向上を図ることができる。
【００３０】
図５〜図８に示すように，吸気分配箱３０は，合成樹脂製の分配箱本体４３と，Ａｌ合金，Ｍｇ合金等の軽合金を素材とする高圧ダイカスト製の蓋体４４とから構成される。分配箱本体４３は，連結フランジ３２，左右の吸気分岐管３８Ｌ，３８Ｒ及び隔壁３５の一半部３５ａと一体に成形されるもので，吸気分岐管３８Ｌ，３８Ｒと反対側の後壁には，左右両分配室３８Ｌ，３８Ｒに渡って開口する開口部４５が設けられ，その開口部４５の周辺は，内向きの接合フランジ４６となっている。蓋体４４は前記開口部４５を閉鎖するものであって，内側面に，前記開口部４５を囲繞して前記接合フランジ４６に対向するループ状の囲い壁４７と前記隔壁３５の他半部３５ｂとが一体に形成され，また囲い壁４７には複数の取り付けボス４７ａが形成される。そして囲い壁４７をシール部材４９を挟んで前記接合フランジ４６に重ねると共に，取り付けボス４７ａを接合フランジ４６にボルト５１で結合することにより，前記開口部４５は気密に閉鎖される。その際，隔壁３５の一半部３５ａと他半部３５ｂ間にもシール部材５２が介裝される。
【００３１】
上下一対の前記弁孔４０及び開閉弁４１は隔壁他半部３５ｂに設けられる。各弁孔４０は長辺を上下方向に向けた長方形に形成され，それに対応して各開閉弁４１も長方形をなしている。上下一対の開閉弁４１は，上下方向に延びる共通１本の弁軸５３に取り付けられ，その弁軸５３は，蓋体４４の下端面から隔壁他半部３５ｂにドリル加工された同軸３個の軸受孔５４ａ，５４ｂ，５４ｃで両端部及び中間部を回転自在に支承される。
【００３２】
両弁孔４０は，隔壁３５の長手方向中央部より，軸受孔５４ａ，５４ｂ，５４ｃの加工開始端側である下端側に全体的にオフセット配置される。こうすると，弁軸５３のスパンを開閉弁４１の支持にのみ必要な最小長さに設定することができると共に，軸受孔５４ａ，５４ｂ，５４ｃの加工に際しては比較的短いドリルの使用が可能となり，各軸受孔５４ａ，５４ｂ，５４ｃの加工精度を，高度の熟練をようすることなく容易に上げることができる。また軸受孔５４ａ，５４ｂ，５４ｃの加工開始端は，吸気入口３１と反対側に位置するので，吸気入口３１の存在に関係なく比較的短いドリルをもって各軸受孔５４ａ，５４ｂ，５４ｃを容易且つ高精度に加工することができる。
【００３３】
こうして，蓋板９８と一体の隔壁他半部３５ｂに開閉弁４１が軸支されるので，蓋板９８及び開閉弁４１の組立体を組み立てた後，その蓋板９８を吸気分配箱３０に固着することにより，開閉弁４１付きの吸気分配箱３０を能率良く組み立てることができる。また分配箱本体４３の接合フランジ４６に結合される蓋体４４内面のループ状の囲い壁４７は，吸気分配箱３０の必要容積を確保しながら，隔壁他半部３５ｂと共に蓋体４４の剛性を強化する補強リブの機能をも果たし，蓋体４４の成形後の反りや分配箱本体４３へのボルト締め付け力による歪みを防止しながら，蓋体４４の薄肉化，延いては軽量化に寄与することができる。
【００３４】
特に，弁孔４０を有する蓋体４４は，吸入分岐管３８Ｌ，３８Ｒと一体の分配箱本体４３に比して小型且つ形状が単純であるから，高圧ダイカスト等の精密鋳造が可能となる。したがって，弁孔４０の後加工が不要で，しかも高剛性で，且つ周囲の温度変化によっても歪みを生ずることがない高品質の蓋体４４が容易に得ることができる。
【００３５】
また蓋体４４は，その内面の囲い壁体４７により効果的に補強されるため，特に蓋体４４と一体の隔壁他半部３５ｂに穿設された軸受孔５４ａ，５４ｂ，５４ｃに変形を来すことがなく，上記軸受孔５４ａ，５４ｂ，５４ｃに弁軸５３を支承させる開閉弁４１を，周囲温度の変化に関係なく常にスムーズに開閉作動することができる。さらに蓋体４４内面の囲い壁体４７は，蓋体４４の鋳造時の湯路を拡大する役目をも果たし，蓋体４４の鋳造性を高めるので，品質の向上にも寄与する。
【００３６】
蓋体４４の外壁には，弁孔４０に対応する部分に外方への膨出部４４ａが形成され，その形成により，その部分の隔壁他半部３５ｂの高さの増加を得て，開口面積の大なる弁孔４０の形成が可能となる。またその膨出部４４ａにより吸気分配箱３０の容積増加を図ることもできる。
【００３７】
さらに弁孔４０の型成形を可能にするため，図９に示すように，隔壁他半部３５ｂは，軸受孔５４ａ，５４ｂ，５４ｃに沿って弁孔４０を分割するように，隔壁他半部主体５５と隔壁片５６とに分割され，各弁孔４０は，隔壁他半部主体５５に成形した比較的深い切欠き４０ａと，各隔壁片５６に成形した比較的浅い切欠き４０ｂとで構成される。隔壁片５６は，その両端部を隔壁他半部主体５５にボルト５７で結合される（図１２参照）。
【００３８】
而して，隔壁他半部主体５５及び隔壁片５６の鋳造時，それらの切欠き４０ａ，４０ｂは簡単に型成形することができるので，鋳造後，面倒な弁孔加工が不要となり，生産性の向上を図ることができる。また弁孔４０を複数とすると共に，これらを開閉する複数の開閉弁４１に共通な弁軸５３の両端部及び中間部を，隔壁他半部３５ｂの複数の軸受孔５４ａ，５４ｂ，５４ｃにより支承するようにしたので，弁孔４０の総合開口面積を大きく設定しつゝ弁軸５３の撓みを防ぎ，開閉弁４１のスムーズな開閉作動を確保することができる。
【００３９】
図９，図１１及び図１３において，前記弁軸５３の下端部は蓋体４４の下方に突出しており，その下端部に作動レバー６０が固着される。この作動レバー６０は，周方向に間隔を置いて配置される３本のアーム６０ａ，６０ｂ，６０ｃを備えており，第１のアーム６０ａが，蓋体４４の下端面に形成されたストッパ突起６１に当接することにより開閉弁４１の全開位置が規定され，第２のアーム６０ｂが，上記ストッパ突起６１に調節可能に螺着されたストッパボルト６２に当接することにより開閉弁４１の全閉位置が規定されるようになっている。そして作動レバー６０には，開閉弁４１を開き方向に付勢する弁ばね６３が接続される。
【００４０】
第３のアーム６０ｃには，負圧アクチュエータ６４の作動杆６５が連結される。負圧アクチュエータ６４は，蓋体４４の下面にねじ止めされたブラケット６７に支持されるケーシング６６と，ケーシング６６の内部を大気室６９と作動室７０とに区画して外周縁をケーシング６６に結合されるダイヤフラム７１とを備えており，このダイヤフラム７１の中心に，大気室６９を貫通して前記第３のアーム６０ｃにピボット連結される作動杆６５が固着される。また作動室７０には，ダイヤフラム７１を開閉弁４１の開き方向に付勢する戻しばね７２が収容される。
【００４１】
負圧アクチュエータ６４のケーシング６６には，上記負圧室に連なる負圧導入管７３が突設され，これと負圧タンク７４とを結ぶ負圧導管７５の途中に制御７６が介裝される。この制御７６は電磁弁で構成され，図示しない電子制御ユニットによる制御により，エンジンＥの低速運転域では励磁されて負圧導管７５を導通状態にし，高速運転域で消磁されて負圧導管７５を不通にすると共に，負圧アクチュエータ６４の負圧室を大気に解放するようになっている。したがって，エンジンＥの低速運転域では，負圧アクチュエータ６４が作動して開閉弁４１を閉じ，高速運転域になると，負圧アクチュエータ６４が不作動状態となるので，開閉弁４１は弁ばね６３の付勢力で開くことになる。
【００４２】
前記負圧タンク７４には，前記吸気分配箱３０の上部に形成した負圧取り出し管７８に連なる負圧導管７９が接続され，この負圧導管７９の途中に，負圧タンク７４から負圧取り出し管７８への負圧の逆流を阻止するチェック弁８０が介裝される。したがって，エンジンＥの運転中，吸気分配箱３０に発生する吸気負圧を負圧導管７９及びチェック弁８０を通して負圧タンク７４に蓄えることができる。
【００４３】
図９及び図１０に示すように，蓋体４４の下端面には，最下部の軸受孔２２ａの外端に隣接する環状のシールハウジング８２と，更にシールハウジング８２の外端に隣接するワッシャハウジング８３とが形成される。シールハウジング８２には環状のシール部材８４が装着され。ワッシャハウジング８３には，弁軸５３の外周に係止されてシール部材８４の外端面に対向するクリップ８５と，このクリップ８５に回転摺動可能に当接する１枚もしくは複数枚のワッシャ８６が収容され，このワッシャ８６の離脱を阻止する押さえ板８７が蓋体４４の下面にねじ止めされる。上記シール部材８４はゴム等の弾性材からなるもので，その内周面には，互いに離反する方向に突出して弁軸５３の外周面に密接する一対のシールリップ８４ａ，８４ｂを一体に備え，また外周面には，シールハウジング８２の内周面に圧入される金属製の補強環８９が焼き付けられている。
【００４４】
而して，エンジンＥの運転中，吸気分配箱３０内で吸気脈動，即ち負圧と正圧が交互に繰り返される圧力変動が発生しても，シール部材８４の上記シールリップ８４ａ，８４ｂにより，最下部の軸受孔５４ａを通して外気が吸気分配箱３０内に侵入したり，吸気分配箱３０内の圧力が漏出したりすることを確実に防ぎ，吸気道吸気分配箱３０への埃の侵入や，吹き返し時の燃料，ブローバイオイル等の漏出を回避することができる。
【００４５】
図１３に示すように，アクチュエータ６４は，吸気分配箱３０の下方への投影図形内に収まるように配置される。その際，アクチュエータ６４の吸気分配箱３０に対する干渉を回避すべく，図６及び図１１に示すように，吸気分配箱３０の下面にアクチュエータ６４の上部を受容する凹部９０が形成される。
【００４６】
而して，開閉弁４１を開閉駆動するアクチュエータ６４の位置は，開閉弁４１の弁軸５３に対する作動レバー６０の結合位置の選定により，弁軸５３の周囲で自由に設定し得るため，このアクチュエータ６４を前方に傾けるだけで，吸気分配箱３０の上下方向投影図形の領域内に収めることが可能であり，したがってアクチュエータ６４と，これにより吸気分配箱３０の後面に近接したエンジンフード１２の後壁との干渉を簡単に回避することができる。しかも吸気入口３１及びアクチュエータ６４は，吸気分配箱３０の上下両端部に配置されるので，それらの干渉をも回避して，吸気装置のコンパクト化を図ることができる。しかも吸気分配箱３０下面の凹部９０にアクチュエータ６４の上部を受容させることにより比較的大型のアクチュエータ６４を吸気分配箱３０やエンジンフード１２に干渉させることなく，狭いエンジンルームに設置することができる。
【００４７】
以上，本発明の実施例を詳述したが，本発明はその要旨を逸脱しない範囲で種々の設計変更を行うことが可能である。例えば，本発明は自動車用エンジンの吸気装置に適用することもできる。
【００４８】
【発明の効果】
以上のように本発明によれば，第１及び第２バンクを有するエンジンの一側に配設される吸気分配箱の一端部に，スロットルボディの吸気道に連なる吸気入口を設け，また前記吸気分配箱内を隔壁により，前記吸気入口にそれぞれ連通する第１及び第２分配室に区画すると共に，該隔壁に，第１及び第２分配室間を連通，遮断し得る開閉弁を設け，前記前記第１及び第２分配室にそれぞれ開口すると共に，前記第１及び第２のバンクの吸気ポートにそれぞれ連なる第１及び第２吸気分岐管を前記吸気分配箱に連設した，多気筒エンジンの吸気装置において，前記吸気入口，前記第１及び第２吸気分岐管並びに前記隔壁の一半部を有すると共に，前記第１及び第２分配室間に渡る開口部を前記第１及び第２分岐管と反対側の外側壁に設けた分配箱本体と，前記隔壁の他半部を有すると共に，前記開口部を囲繞しながら前記分配箱本体の外側面に着脱可能に接合されるループ状の囲い壁を内側面に一体に突設した軽合金鋳造製の蓋体とで前記吸気分配箱を構成し，前記他半部には，前記第１及び第２分配室間を連通する弁孔と，この弁孔を開閉する開閉弁の弁軸を支承する軸受孔とを設け，前記弁孔を拡大すべく前記蓋体の，前記弁孔に対応する部分に外方膨出部を形成し，クランク軸を縦置きにした船外機用エンジンの後向きにした第１及び第２バンクの頭部と，このエンジンを覆う船外機用エンジンフードの後壁との間に前記吸気分配箱を上下に長く配置し，該吸気分配箱の上端部に前記吸気入口を設ける一方，該吸気分配箱の下端部に，前記弁軸を介して前記開閉弁を駆動するアクチュエータを取り付けたので，蓋体及び開閉弁で１個の組立体を構成することになり，蓋体を分配箱本体から取り外すことにより，開閉弁及びその周辺のメンテナンスを容易に行うことができる。
【００４９】
しかも軽合金鋳造製の蓋体は，吸気分配箱の軽量化に寄与すると共に，周囲の温度変化に影響されずに所定形状を維持し得る上，内面の囲い壁により効果的に補強されるため，蓋体と一体の隔壁他半部に穿設された，弁軸の軸受孔に変形を来すことがなく，開閉弁の安定した作動を確保することができる。
【００５０】
さらに蓋体内面の囲い壁は，蓋体の鋳造時の湯路を拡大する役目をも果たし，蓋体の鋳造性を高めるので，品質の向上にも寄与する。また蓋体の，弁孔に対応する部分に形成された外方膨出部により，その部分の隔壁他半部の高さの増加を得て，開口面積の大なる弁孔の形成が可能となるのみならず，その外方膨出部により吸気分配箱の容積増加を図ることをできる。
【００５１】
特に，弁孔を有する蓋体は，吸入分岐管と一体の分配箱本体に比して小型且つ形状が単純であるから，高圧ダイカスト等の精密鋳造が可能となる。したがって，弁孔の後加工が不要で，しかも高剛性で，且つ周囲の温度変化によっても歪みを生ずることがない高品質の蓋体が容易に得られと共に，それに軸支される開閉弁の良好な開閉作動を，周囲温度の変化に関係なく常に確保することができる。
【００５２】
さらに船外機において，吸気入口とアクチュエータとの干渉を回避しながら，エンジンの第１及び第２バンクとエンジンフードとの間の狭小なスペースに吸気装置をコンパクトに収容することができる。
【図面の簡単な説明】
【図１】本発明の実施例に係る船外機の全体側面図。
【図２】図１の要部縦断面図。
【図３】図２の３−３線断面図。
【図４】図２の４−４線断面図。
【図５】図４の５−５線断面図。
【図６】図５の６−６線断面図。
【図７】図５の７−７線断面図。
【図８】図５に対応した吸気マニホールドの要部分解図。
【図９】図８の９−９線断面図。
【図１０】図９の１０部拡大図。
【図１１】図８の１１矢視図。
【図１２】図１１の１２−１２線断面図。
【図１３】図１１の１３−１３線断面図。
【符号の説明】
Ｅ・・・・・エンジン
Ｏ・・・・・船外機
４・・・・・クランク軸
６Ｌ，６Ｒ・・・第１及び第２バンク（左右のバンク）
１２・・・・エンジンフード
２２・・・・スロットルボディ
２２ａ・・・吸気道
２５Ｌ，２５Ｒ・・・第１及び第２バンクの吸気ポート
３０・・・・吸気分配箱
３１・・・・吸気入口
３５・・・・隔壁
３５ａ・・・隔壁の一半部
３５ｂ・・・隔壁の他半部
３７Ｌ，３７Ｒ・・・第１及び第２分配室（左右の分配室）
３８Ｌ，３８Ｒ・・・第１及び第２吸気分岐管（左右の吸気分岐管）
４０・・・・弁孔
４１・・・・開閉弁
４３・・・・分配箱本体
４４・・・・蓋体
４４ａ・・・外方膨出部
４５・・・・開口部
４７・・・・囲い壁
５３・・・・弁軸
５４ａ〜５４ｃ・・・軸受孔
５５・・・・壁他半部主体
５６・・・・隔壁片
６４・・・・アクチュエータ[0001]
BACKGROUND OF THE INVENTION
In the present invention, an intake inlet connected to an intake passage of a throttle body is provided at one end of an intake distribution box disposed on one side of an engine having first and second banks, and the inside of the intake distribution box is separated by a partition. The first and second distribution chambers communicating with the intake port, respectively, and the partition wall is provided with an opening / closing valve capable of communicating and blocking between the first and second distribution chambers. First and second intake branch pipes that open to the distribution chambers and communicate with the intake ports of the first and second banks, respectively, are connected to the intake distribution box, and the on-off valve is operated according to the operating state of the engine. The present invention relates to an improvement in an intake system for a multi-cylinder engine that can change the intake characteristics by opening and closing the engine to achieve high output performance in a wide operating range from low speed to high speed of the engine.
[0002]
[Prior art]
Such an intake device for a multi-cylinder engine is already known as disclosed in, for example, Japanese Patent Laid-Open No. 9-88746.
[0003]
[Problems to be solved by the invention]
By the way, in the intake device disclosed in the above publication, a partition body having a valve hole that is pivotally supported by the on-off valve and opened and closed by the on-off valve is interposed between the distribution box body and the intake manifold. Because of this structure, maintenance of the on-off valve requires troublesome work of disassembling the distribution box main body and the intake manifold, so maintenance is not good.
[0004]
The present invention has been made in view of such circumstances, and it is possible to perform maintenance of the on-off valve by simply removing the outer cover from the intake distribution box, and to ensure stable operation of the on-off valve. It is an object of the present invention to provide an intake device for a multi-cylinder engine that can be used.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an intake inlet connected to the intake passage of the throttle body at one end of an intake distribution box disposed on one side of the engine having the first and second banks. The intake distribution box is partitioned by a partition into first and second distribution chambers that communicate with the intake inlet, and an on-off valve is provided in the partition to allow communication between the first and second distribution chambers. , A multi-cylinder opening in the first and second distribution chambers and having first and second intake branch pipes connected to the intake ports of the first and second banks connected to the intake distribution box, respectively. In the engine intake system, the intake inlet, the first and second intake branch pipes, and a half of the partition wall are provided, and an opening extending between the first and second distribution chambers is provided in the first and second branch chambers. Installed on the outer wall opposite the tube A distribution box main body and a loop-shaped enclosure wall that has the other half of the partition wall and is detachably joined to the outer side surface of the distribution box main body while surrounding the opening. The light alloy casting lid body constitutes the air intake distribution box, and the other half includes a valve hole communicating with the first and second distribution chambers, and an on-off valve for opening and closing the valve hole. An outboard motor provided with a bearing hole for supporting the valve shaft, an outwardly bulging portion formed in a portion of the lid corresponding to the valve hole to enlarge the valve hole, and a crankshaft placed vertically The intake distribution box is arranged vertically long between the heads of the first and second banks facing the rear of the engine and the rear wall of the engine hood for the outboard motor that covers the engine. The intake inlet is provided at the upper end, and the open / close valve is driven through the valve shaft at the lower end of the intake distribution box. That was attached actuator and first feature.
[0006]
According to the first feature, since one assembly is constituted by the lid and the on-off valve, maintenance of the on-off valve and its surroundings can be easily performed by removing the lid from the distribution box body. Can contribute to improvement of maintainability.
[0007]
In addition, the light alloy cast lid contributes to the weight reduction of the air intake distribution box, and can maintain the predetermined shape without being affected by the surrounding temperature change, and is effectively reinforced by the inner wall. The stable operation of the on-off valve can be ensured without causing deformation in the bearing hole of the valve shaft, which is formed in the other half of the partition wall integral with the lid. In addition, the enclosure wall on the inner surface of the lid serves to expand the runner during casting of the lid and enhances the castability of the lid, thus contributing to improved quality.
[0008]
In addition, the outward bulge formed on the part of the lid that corresponds to the valve hole allows an increase in the height of the other half of the bulkhead to allow the formation of a valve hole with a large opening area. In addition, the volume of the intake distribution box can be increased by the outward bulging portion.
[0009]
In particular, the lid having a valve hole is smaller and simpler in shape than the distribution box body integrated with the suction branch pipe, so that precision casting such as high-pressure die casting is possible. Therefore, it is easy to obtain a high-quality lid that does not require post-processing of the valve hole, is highly rigid, and does not cause distortion even when the ambient temperature changes. Can be ensured at all times regardless of changes in ambient temperature.
[0010]
Furthermore, in the outboard motor, the intake device can be compactly accommodated in a narrow space between the first and second banks of the engine and the engine hood while avoiding interference between the intake inlet and the actuator.
[0011]
According to the present invention , in addition to the first feature, the first and second branch pipes are arranged on the front wall of the intake distribution box facing the valley between the first and second banks. The second feature is that they are integrally molded so as to be disposed inside .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The form of the Example of this invention is demonstrated below based on one Example of this invention shown to an accompanying drawing.
[0013]
1 is an overall side view of the outboard motor, FIG. 2 is a longitudinal sectional view of the main part of FIG. 1, FIG. 3 is a sectional view taken along line 3-3 in FIG. 2, and FIG. 5 is a sectional view taken along line 5-5 in FIG. 4, FIG. 6 is a sectional view taken along line 6-6 in FIG. 5, FIG. 7 is a sectional view taken along line 7-7 in FIG. 9 is a sectional view taken along line 9-9 of FIG. 8, FIG. 10 is an enlarged view of 10 part of FIG. 9, FIG. 11 is a view taken along arrow 11 in FIG. 8, and FIG. FIGS. 13A and 13B are sectional views taken along line 13-13 in FIG.
[0014]
In the following description, front / rear and left / right refer to the hull H to which the outboard motor O is attached.
[0015]
In FIG. 1 to FIG. 3, the outboard motor O attached to the rear end of the hull H is connected to the mount case 1, the extension case 2 connected to the lower end surface of the mount case 1, and the lower end surface of the extension case 2. The V-type 6-cylinder water-cooled four-stroke engine E is mounted on the upper end surface of the mount case 1 with the crankshaft 4 placed vertically.
[0016]
An annular under cover 14 is fixed to the mount case 1 via a stay 13. The under cover 14 covers the periphery of the section from the lower part of the engine E to the upper part of the extension case 2, and an engine hood 12 that covers the engine E from above is detachably attached to the upper end thereof. The engine hood 12 and the under cover 14 define an engine room 15 that houses the engine E.
[0017]
The engine E has a crankcase 5 that supports the vertically placed crankshaft 4 and a pair of left and right banks 6L and 6R that spread in a V shape from the crankcase 5 to the rear. The lower surface is bolted to the upper mounting surface of the mount case 1.
[0018]
As shown in FIGS. 5 and 6, each bank 6L, 6R includes a plurality (three in the illustrated example) of cylinder bores 7L, 7R arranged vertically. The left and right banks 6L and 6R are bolted to the rear end surface of the crankcase 25, and the cylinder block 7 having the left and right cylinder bores 7L and 7R, and the left and right sides of the cylinder block 7 where the cylinder bores 7L and 7R are opened. A pair of cylinder heads 9L, 9R coupled to the rear end surfaces by bolts, and a pair of head covers 10L coupled to the rear end surfaces of the cylinder heads 9L, 9R to close the valve operating chambers formed in the cylinder heads 9L, 9R. 10R.
[0019]
2 to 4, an air intake 16 is provided at the upper rear surface of the engine hood 12, and a flat ventilation duct 17 that communicates with the air intake 16 and opens the lower end to the lower portion of the engine room 15 is an engine hood. 12 is disposed along the inner surface of the rear wall. The air taken into the engine room 15 by the ventilation duct 17 is taken into the left and right banks 6L and 6R through the intake silencer 18 and the intake manifold Mi.
[0020]
The intake silencer 18 is attached to the upper surface of the engine E, has a box shape, and includes a pair of left and right inlets 20 and 20 and an outlet 21 disposed between the inlets 20 and 20. An upstream end of the intake passage 22 a of the throttle body 22 is connected to the outlet 21. A throttle valve 23 that is linked to an accelerator lever (not shown) provided on the hull H is pivotally supported on the intake passage 22a.
[0021]
5 to 7, the intake manifold Mi connected to the downstream end of the intake passage 22a of the throttle body 22 is disposed facing the valley 24 between the left and right banks 6L, 6R. The valley 24 is connected to a plurality of left intake pipes 26L connected to a plurality of intake ports 25L of the cylinder head 9L of the left bank 6L and a plurality of intake ports 25R formed in the cylinder head 9R of the right bank 6R. A plurality of right intake pipes 26R are arranged with their upstream ends directed rearward. A left connecting flange 27L that interconnects the left intake pipes 26L is integrally formed at the upstream ends of the plurality of left intake pipes 26L, and a right connection flange 27R that connects them mutually at the upstream ends of the plurality of right intake pipes 26R. Are integrally formed. Electromagnetic fuel injection valves 28L and 28R for injecting fuel toward the intake valves of the corresponding banks 6L and 6R are attached to the intake pipes 26L and 26R of the left and right banks 6L and 6R.
[0022]
The intake manifold Mi includes an intake distribution box 30 that is long in the vertical direction and flat in the front-rear direction, and is arranged so as to straddle both rear surfaces of the left and right banks 6L and 6R. A connection flange 32 having an intake inlet 31 at the center is formed on the upper portion of the front wall of the intake distribution box 30, and a connection flange 33 formed at the downstream end of the throttle body 22 is coupled to the connection flange 32.
[0023]
A partition wall 35 extending in the vertical direction is provided in the intake distribution box 30, whereby the interior of the intake distribution box 30 is partitioned into a left distribution chamber 37 </ b> L and a right distribution chamber 37 </ b> R that communicate with the intake inlet 31, respectively. The partition wall 35 is provided with a guide wall 36 for diverting the air flowing into the intake port 31 to the left and right distribution chambers 37L and 37R.
[0024]
A plurality of left intake branch pipes 38L and right intake branch pipes 38R communicating with the left and right distribution chambers 37L and 37R are disposed in the intake distribution box 30 on the front wall facing the valley 24 of the intake distribution box 30. It is integrally molded so. The downstream ends of the left and right intake branch pipes 38L and 38R are integrally formed with one connection flange 39 for connecting them to each other, and this is bolted to the connection flanges 27L and 27R of the left and right intake pipes 26L and 26R. Combined.
[0025]
The partition wall 35 that divides the inside of the intake distribution box 30 into left and right distribution chambers 37L and 37R is provided with a pair of upper and lower valve holes 40 that directly communicate between the distribution chambers 37L and 37R. A pair of butterfly type on-off valves 41 is pivotally supported.
[0026]
Thus, during operation of the engine E, the air flowing into the left and right inlets 20 and 20 of the intake silencer 18 merges in the intake silencer 18, exits the outlet 21, passes through the intake passage 22 a of the throttle body 22, The intake manifold Mi is directed toward the intake inlet 31 of the intake distribution box 30. At that time, in the intake passage 22a, the intake amount of the engine E is controlled by the opening degree of the throttle valve 23.
[0027]
In the low-speed operation region of the engine E, the on-off valve 41 in the intake distribution box 30 is closed, and the air flowing into the intake inlet 31 of the intake manifold Mi flows into the left and right distribution chambers 37L and 37R extending vertically. Divide. The air divided into the left distribution chamber 37L is further divided into a plurality of left intake branch pipes 38L, passes through the left intake pipe 26L, passes through the intake port 25L of the left bank 6L, and is sucked into the corresponding cylinder bore 27L. The air divided into the right distribution chamber 37R is further divided into a plurality of right intake branch pipes 38R, passes through the right intake pipe 26R, passes through the intake port 25R of the right bank 6R, and is sucked into the corresponding cylinder bore 27R.
[0028]
By the way, in the low-speed operation region of the engine E, the left distribution chamber 37L and the right distribution chamber 37R in which the upstream ends of the left and right intake branch pipes 38L and 38R open are closed except for the communication portion with the upper intake inlet 31. The open / close valve 41 shuts off the intake system from the left distribution chamber 37L to the intake port 25L of the left bank 6L and the intake system from the right distribution chamber 37R to the intake port 25R of the right bank 6R. Two resonant supercharging intake systems that do not cause intake interference are configured, and the natural vibration of each resonant supercharging intake system is approximately the opening / closing cycle of the intake valves of the banks 6L and 6R in the low speed operation region of the engine E. Therefore, the resonance supercharging effect is effectively exhibited, the intake charging efficiency in the low speed operation region of the engine is increased, and the output performance can be improved.
[0029]
In the high-speed operation region of the engine E, the on-off valve 41 in the intake distribution box 30 is opened, whereby the left and right distribution chambers 37L and 37R communicate with each other via the valve hole 40 and have a large capacity. Since one surge tank is formed and the upstream ends of the left and right intake branch pipes 38L and 38R are opened in the surge tank, the intake inertia capacity in each of the banks 6L and 6R is increased, and the resonance intake system is substantially reduced. As the length decreases, the natural frequency of the resonant intake system increases to coincide with the opening / closing cycle of the intake valves of the banks 6L and 6R in the high-speed operation region of the engine E, and the resonance supercharging effect is effectively exhibited. As a result, the intake charge efficiency in the high-speed operation region of the engine E increases, and the output performance can be improved.
[0030]
As shown in FIGS. 5 to 8, the intake distribution box 30 includes a distribution box main body 43 made of synthetic resin and a lid body 44 made of high pressure die casting made of a light alloy such as an Al alloy or Mg alloy. The The distribution box main body 43 is formed integrally with the connecting flange 32, the left and right intake branch pipes 38L and 38R, and the half portion 35a of the partition wall 35. The rear wall opposite to the intake branch pipes 38L and 38R has left and right An opening 45 is provided to open over both the distribution chambers 38L and 38R, and the periphery of the opening 45 is an inward joint flange 46. The lid 44 closes the opening 45, and has a loop-shaped surrounding wall 47 surrounding the opening 45 and facing the joining flange 46 on the inner side surface, and the other half 35 b of the partition wall 35. And a plurality of mounting bosses 47 a are formed on the surrounding wall 47. Then, the opening wall 45 is hermetically closed by overlapping the surrounding wall 47 on the joint flange 46 with the seal member 49 interposed therebetween, and connecting the mounting boss 47a to the joint flange 46 with the bolt 51. At that time, the seal member 52 is also interposed between the half portion 35a and the other half portion 35b of the partition wall 35.
[0031]
The pair of upper and lower valve holes 40 and the on-off valve 41 are provided in the other half portion 35b of the partition wall. Each valve hole 40 is formed in a rectangular shape whose long side is directed in the vertical direction, and correspondingly, each on-off valve 41 has a rectangular shape. The pair of upper and lower on-off valves 41 are attached to one common valve shaft 53 extending in the vertical direction. The valve shaft 53 is formed by three coaxially drilled holes from the lower end surface of the lid body 44 to the other half portion 35b of the partition wall. Both end portions and an intermediate portion are rotatably supported by the bearing holes 54a, 54b, 54c.
[0032]
Both valve holes 40 are disposed offset from the center in the longitudinal direction of the partition wall 35 on the lower end side, which is the processing start end side of the bearing holes 54a, 54b, 54c. In this way, the span of the valve shaft 53 can be set to the minimum length necessary only for supporting the on-off valve 41, and a relatively short drill can be used when processing the bearing holes 54a, 54b, 54c. The processing accuracy of each of the bearing holes 54a, 54b, 54c can be easily increased without requiring a high degree of skill. Further, since the machining start ends of the bearing holes 54a, 54b, 54c are located on the side opposite to the intake inlet 31, the bearing holes 54a, 54b, 54c can be easily and highly raised with a relatively short drill regardless of the presence of the intake inlet 31. It can be processed with high accuracy.
[0033]
Thus, the on-off valve 41 is pivotally supported on the other half portion 35b of the partition wall integral with the lid plate 98. Therefore, after the assembly of the lid plate 98 and the on-off valve 41 is assembled, the lid plate 98 is fixed to the intake distribution box 30. By doing so, the intake distribution box 30 with the on-off valve 41 can be assembled efficiently. Further, the loop-shaped enclosure wall 47 on the inner surface of the lid body 44 coupled to the joint flange 46 of the distribution box main body 43 secures the required volume of the intake distribution box 30 and increases the rigidity of the lid body 44 together with the other half portion 35b of the partition wall. It also functions as a reinforcing rib to reinforce, and contributes to reducing the thickness of the lid 44 and thus reducing its weight while preventing warping after molding of the lid 44 and distortion due to the bolt tightening force to the distribution box body 43. be able to.
[0034]
In particular, the lid body 44 having the valve hole 40 is smaller and simpler in shape than the distribution box main body 43 integrated with the suction branch pipes 38L and 38R, so that precision casting such as high-pressure die casting is possible. Therefore, it is possible to easily obtain a high-quality lid body 44 that does not require post-processing of the valve hole 40, has high rigidity, and does not cause distortion even when the ambient temperature changes.
[0035]
Further, since the lid body 44 is effectively reinforced by the surrounding wall body 47, the bearing holes 54a, 54b, 54c formed in the other half portion 35b integral with the lid body 44 are particularly deformed. Therefore, the on-off valve 41 that supports the valve shaft 53 in the bearing holes 54a, 54b, 54c can always be opened and closed smoothly regardless of changes in the ambient temperature. Furthermore, the enclosure wall body 47 on the inner surface of the lid body 44 also serves to expand the runner when the lid body 44 is cast, and improves the castability of the lid body 44, thereby contributing to the improvement of quality.
[0036]
On the outer wall of the lid body 44, an outwardly bulging portion 44a is formed at a portion corresponding to the valve hole 40, and by the formation, an increase in the height of the other half portion 35b of the partition wall is obtained to open the portion. The valve hole 40 having a large area can be formed. Further, the volume of the intake distribution box 30 can be increased by the bulging portion 44a.
[0037]
Further, in order to allow the molding of the valve hole 40, as shown in FIG. 9, the other partition wall half portion 35b is divided into the valve hole 40 along the bearing holes 54a, 54b, 54c. The valve hole 40 is divided into a main body 55 and a partition piece 56, and each valve hole 40 includes a relatively deep notch 40 a formed in the partition wall other half main body 55 and a relatively shallow notch 40 b formed in each partition piece 56. Is done. Both ends of the partition piece 56 are coupled to the partition other half main body 55 by bolts 57 (see FIG. 12).
[0038]
Thus, the notches 40a and 40b can be easily molded when the partition wall other half main body 55 and the partition piece 56 are cast. Can be improved. Further, a plurality of valve holes 40 are provided, and both end portions and intermediate portions of the valve shaft 53 common to the plurality of on-off valves 41 for opening and closing the valve holes 40 are supported by a plurality of bearing holes 54a, 54b, 54c in the other partition half portion 35b. As a result, the valve shaft 53 can be prevented from being bent while the overall opening area of the valve hole 40 is set large, and a smooth opening / closing operation of the opening / closing valve 41 can be ensured.
[0039]
9, 11 and 13, the lower end portion of the valve shaft 53 protrudes below the lid body 44, and the operating lever 60 is fixed to the lower end portion. The actuating lever 60 includes three arms 60 a, 60 b, 60 c arranged at intervals in the circumferential direction, and the first arm 60 a is a stopper projection 61 formed on the lower end surface of the lid 44. , The fully open position of the on-off valve 41 is defined, and the second arm 60b abuts on a stopper bolt 62 that is adjustably screwed to the stopper protrusion 61, whereby the on-off valve 41 is fully closed. It has come to be specified. A valve spring 63 that biases the opening / closing valve 41 in the opening direction is connected to the operating lever 60.
[0040]
An operating rod 65 of a negative pressure actuator 64 is connected to the third arm 60c. The negative pressure actuator 64 includes a casing 66 supported by a bracket 67 screwed to the lower surface of the lid 44, an interior of the casing 66 is divided into an air chamber 69 and a working chamber 70, and an outer peripheral edge is coupled to the casing 66. An operating rod 65 that is pivotally connected to the third arm 60c through the atmosphere chamber 69 is fixed to the center of the diaphragm 71. The working chamber 70 also houses a return spring 72 that biases the diaphragm 71 in the opening direction of the on-off valve 41.
[0041]
A negative pressure introduction pipe 73 connected to the negative pressure chamber projects from the casing 66 of the negative pressure actuator 64, and a control 76 is interposed in the middle of a negative pressure conduit 75 connecting the negative pressure tank 74. This control 76 is constituted by an electromagnetic valve, and is excited in the low speed operation region of the engine E to make the negative pressure conduit 75 conductive by the control of an electronic control unit (not shown) and demagnetized in the high speed operation region. In addition, the negative pressure chamber of the negative pressure actuator 64 is released to the atmosphere. Accordingly, the negative pressure actuator 64 is operated to close the on-off valve 41 in the low speed operation region of the engine E, and the negative pressure actuator 64 is inactivated in the high speed operation region. It will open with a biasing force.
[0042]
The negative pressure tank 74 is connected to a negative pressure conduit 79 connected to a negative pressure extraction pipe 78 formed at the top of the intake distribution box 30, and the negative pressure is extracted from the negative pressure tank 74 in the middle of the negative pressure conduit 79. A check valve 80 is interposed to prevent negative pressure backflow into the tube 78. Accordingly, the intake negative pressure generated in the intake distribution box 30 during operation of the engine E can be stored in the negative pressure tank 74 through the negative pressure conduit 79 and the check valve 80.
[0043]
As shown in FIGS. 9 and 10, the lid 44 has an annular seal housing 82 adjacent to the outer end of the lowermost bearing hole 22 a and a washer housing adjacent to the outer end of the seal housing 82. 83 is formed. An annular seal member 84 is attached to the seal housing 82. The washer housing 83 accommodates a clip 85 that is locked to the outer periphery of the valve shaft 53 and faces the outer end surface of the seal member 84, and one or a plurality of washers 86 that abut against the clip 85 so as to be able to rotate and slide. Then, a holding plate 87 that prevents the washer 86 from being detached is screwed to the lower surface of the lid 44. The seal member 84 is made of an elastic material such as rubber, and has a pair of seal lips 84a and 84b integrally protruding on the inner peripheral surface thereof and projecting in directions away from each other and in close contact with the outer peripheral surface of the valve shaft 53, A metal reinforcing ring 89 that is press-fitted into the inner peripheral surface of the seal housing 82 is baked on the outer peripheral surface.
[0044]
Thus, even if the intake pulsation, that is, the pressure fluctuation in which the negative pressure and the positive pressure are alternately repeated, occurs in the intake distribution box 30 during the operation of the engine E, the seal lips 84a and 84b of the seal member 84 It is possible to reliably prevent outside air from entering the intake distribution box 30 and the pressure in the intake distribution box 30 from leaking through the lowermost bearing hole 54a. It is possible to avoid leakage of fuel, blow bioile, etc. when blown back.
[0045]
As shown in FIG. 13, the actuator 64 is disposed so as to fit within a projection figure below the intake distribution box 30. At this time, in order to avoid the interference of the actuator 64 with the intake distribution box 30, a recess 90 for receiving the upper portion of the actuator 64 is formed on the lower surface of the intake distribution box 30 as shown in FIGS.
[0046]
Thus, the position of the actuator 64 for driving the opening / closing valve 41 can be freely set around the valve shaft 53 by selecting the coupling position of the operating lever 60 with respect to the valve shaft 53 of the opening / closing valve 41. By simply tilting 64 forward, it is possible to fit within the area of the vertical projection figure of the intake distribution box 30, and therefore the actuator 64 and the rear wall of the engine hood 12 adjacent to the rear surface of the intake distribution box 30. Can be easily avoided. In addition, since the intake inlet 31 and the actuator 64 are arranged at both upper and lower ends of the intake distribution box 30, interference between them can be avoided and the intake device can be made compact. In addition, by receiving the upper portion of the actuator 64 in the recess 90 on the lower surface of the intake distribution box 30, the relatively large actuator 64 can be installed in a narrow engine room without causing interference with the intake distribution box 30 and the engine hood 12.
[0047]
As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary. For example, the present invention can be applied to an intake device for an automobile engine.
[0048]
【The invention's effect】
As described above, according to the present invention, an intake inlet connected to the intake passage of the throttle body is provided at one end of the intake distribution box disposed on one side of the engine having the first and second banks. The partition box is partitioned by a partition into first and second distribution chambers that respectively communicate with the intake inlet, and the partition is provided with an on-off valve capable of communicating and blocking between the first and second distribution chambers, A multi-cylinder engine having an opening in each of the first and second distribution chambers and a first and second intake branch pipe connected to the intake ports of the first and second banks respectively connected to the intake distribution box. In the intake device, the intake inlet, the first and second intake branch pipes, and one half of the partition wall are provided, and an opening extending between the first and second distribution chambers is formed between the first and second branch pipes. Distribution on the opposite outer wall A light alloy having a main body and another half of the partition wall, and a loop-shaped enclosure wall that is detachably joined to the outer surface of the distribution box body while surrounding the opening, integrally projecting on the inner surface The intake lid is constituted by a casting lid, and the other half includes a valve hole communicating between the first and second distribution chambers, and a valve shaft of an on-off valve that opens and closes the valve hole. An outboard engine having a bearing hole to be supported, an outwardly bulging portion formed in a portion of the lid corresponding to the valve hole to expand the valve hole, and a crankshaft vertically disposed . The intake distribution box is disposed vertically long between the heads of the first and second banks facing backward and the rear wall of the engine hood for the outboard motor that covers the engine, and is disposed at the upper end of the intake distribution box. While providing the intake inlet, the lower end of the intake distribution box is provided with an actuator for driving the on-off valve via the valve shaft. Because fitted with Chueta, it could be formed into a single assembly with the lid and the opening and closing valve, by removing the lid from the dispensing box body, the opening and closing valve and the maintenance of the periphery thereof can be easily performed.
[0049]
In addition, the light alloy cast lid contributes to the weight reduction of the air intake distribution box, and can maintain the predetermined shape without being affected by the surrounding temperature change, and is effectively reinforced by the inner wall. The stable operation of the on-off valve can be ensured without causing deformation in the bearing hole of the valve shaft, which is formed in the other half of the partition wall integral with the lid.
[0050]
In addition, the enclosure wall on the inner surface of the lid serves to expand the runner during casting of the lid and enhances the castability of the lid, thus contributing to improved quality. In addition, the outward bulge formed on the part of the lid that corresponds to the valve hole allows an increase in the height of the other half of the bulkhead to allow the formation of a valve hole with a large opening area. In addition, the volume of the intake distribution box can be increased by the outward bulging portion.
[0051]
In particular, the lid having a valve hole is smaller and simpler in shape than the distribution box body integrated with the suction branch pipe, so that precision casting such as high pressure die casting is possible. Therefore, it is easy to obtain a high-quality lid that does not require post-processing of the valve hole, is highly rigid, and does not cause distortion even when the ambient temperature changes. Can be ensured at all times regardless of changes in ambient temperature.
[0052]
Further, in the outboard motor, the intake device can be compactly accommodated in a narrow space between the first and second banks of the engine and the engine hood while avoiding interference between the intake inlet and the actuator.
[Brief description of the drawings]
FIG. 1 is an overall side view of an outboard motor according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a main part of FIG.
3 is a cross-sectional view taken along line 3-3 in FIG.
4 is a cross-sectional view taken along line 4-4 of FIG.
5 is a cross-sectional view taken along line 5-5 in FIG.
6 is a cross-sectional view taken along line 6-6 in FIG.
7 is a cross-sectional view taken along line 7-7 in FIG.
FIG. 8 is an exploded view of the main part of the intake manifold corresponding to FIG. 5;
9 is a cross-sectional view taken along line 9-9 in FIG.
10 is an enlarged view of a portion 10 in FIG. 9. FIG.
11 is a view taken in the direction of arrow 11 in FIG. 8;
12 is a sectional view taken along line 12-12 of FIG.
13 is a cross-sectional view taken along line 13-13 in FIG.
[Explanation of symbols]
E ... Engine O ... Outboard motor 4 ... Crankshaft 6L, 6R ... First and second banks (left and right banks)
12. Engine hood 22 ... Throttle body 22a ... Intake passages 25L, 25R ... Intake port 30 of first and second banks ... Intake distribution box 31 ... Intake inlet 35 ··· partition wall 35a ··· one half portion 35b of the partition wall · · · other half portions 37L and 37R of the partition wall ... first and second distribution chambers (left and right distribution chambers)
38L, 38R ... 1st and 2nd intake branch pipes (left and right intake branch pipes)
40 ... Valve hole 41 ... Open / close valve 43 ... Distribution box body 44 ... Lid 44a ... Outward bulging part 45 ... Opening 47 ... Enclosure wall 53... Valve shafts 54 a to 54 c... Bearing hole 55.

Claims

第１及び第２バンク（６Ｌ，６Ｒ）を有するエンジン（Ｅ）の一側に配設される吸気分配箱（３０）の一端部に，スロットルボディ（２２）の吸気道（２２ａ）に連なる吸気入口（３１）を設け，また前記吸気分配箱（３０）内を隔壁（３５）により，前記吸気入口（３１）にそれぞれ連通する第１及び第２分配室（３７Ｌ，３７Ｒ）に区画すると共に，該隔壁（３５）に，第１及び第２分配室（３７Ｌ，３７Ｒ）間を連通，遮断し得る開閉弁（４１）を設け，前記前記第１及び第２分配室（３７Ｌ，３７Ｒ）にそれぞれ開口すると共に，前記第１及び第２のバンク（６Ｌ，６Ｒ）の吸気ポート（２５Ｌ，２５Ｒ）にそれぞれ連なる第１及び第２吸気分岐管（３８Ｌ，３８Ｒ）を前記吸気分配箱（３０）に連設した，多気筒エンジンの吸気装置において，
前記吸気入口（３１），前記第１及び第２吸気分岐管（３８Ｌ，３８Ｒ）並びに前記隔壁（３５）の一半部（３５ａ）を有すると共に，前記第１及び第２分配室（３７Ｌ，３７Ｒ）間に渡る開口部（４５）を前記第１及び第２分岐管（３８Ｌ，３８Ｒ）と反対側の外側壁に設けた分配箱本体（４３）と，前記隔壁（３５）の他半部（３５ｂ）を有すると共に，前記開口部（４５）を囲繞しながら前記分配箱本体（４３）の外側面に着脱可能に接合されるループ状の囲い壁（４７）を内側面に一体に突設した軽合金鋳造製の蓋体（４４）とで前記吸気分配箱（３０）を構成し，前記他半部（３５ｂ）には，前記第１及び第２分配室（３７Ｌ，３７Ｒ）間を連通する弁孔（４０）と，この弁孔（４０）を開閉する開閉弁（４１）の弁軸（５３）を支承する軸受孔（５４ａ〜５４ｃ）とを設け，前記弁孔（４０）を拡大すべく前記蓋体（４４）の，前記弁孔（４０）に対応する部分に外方膨出部（４４ａ）を形成し，クランク軸（４）を縦置きにした船外機（Ｏ）用エンジン（Ｅ）の後向きにした第１及び第２バンク（６Ｌ，６Ｒ）の頭部と，このエンジン（Ｅ）を覆う船外機（Ｏ）用エンジンフード（１２）の後壁との間に前記吸気分配箱（３０）を上下に長く配置し，該吸気分配箱（３０）の上端部に前記吸気入口（３１）を設ける一方，該吸気分配箱（３０）の下端部に，前記弁軸（５３）を介して前記開閉弁（４１）を駆動するアクチュエータ（６４）を取り付けたことを特徴とする，多気筒エンジンの吸気装置。Intake air connected to the intake passage (22a) of the throttle body (22) at one end of an intake distribution box (30) disposed on one side of the engine (E) having the first and second banks (6L, 6R). An inlet (31) is provided, and the inside of the intake distribution box (30) is partitioned by a partition wall (35) into first and second distribution chambers (37L, 37R) communicating with the intake inlet (31), respectively. The partition wall (35) is provided with an on-off valve (41) capable of communicating and blocking between the first and second distribution chambers (37L, 37R), and the first and second distribution chambers (37L, 37R) are respectively provided. The first and second intake branch pipes (38L, 38R) that open and communicate with the intake ports (25L, 25R) of the first and second banks (6L, 6R), respectively, are connected to the intake distribution box (30). Multi-cylinder engine intake system installed in series In,
The intake inlet (31), the first and second intake branch pipes (38L, 38R), and a half (35a) of the partition wall (35), and the first and second distribution chambers (37L, 37R) A distribution box body (43) provided with an opening (45) between them on the outer wall opposite to the first and second branch pipes (38L, 38R), and the other half (35b) of the partition wall (35) And a loop-shaped enclosure wall (47) that is detachably joined to the outer surface of the distribution box body (43) while surrounding the opening (45). The alloy casting lid (44) constitutes the intake distribution box (30), and the other half (35b) communicates between the first and second distribution chambers (37L, 37R). The valve shaft (53) of the opening / closing valve (41) that opens and closes the hole (40) and the valve hole (40) Bearing holes (54a to 54c) to be received, and an outwardly bulging portion (44a) in a portion corresponding to the valve hole (40) of the lid (44) in order to enlarge the valve hole (40). And the heads of the first and second banks (6L, 6R) facing the rear of the engine (E) for the outboard motor (O) with the crankshaft (4) placed vertically, and the engine (E) The intake distribution box (30) is vertically arranged between the rear wall of the engine hood (12) for the outboard motor (O) that covers the intake hood, and the intake inlet ( 31), and an actuator (64) for driving the on-off valve (41) via the valve shaft (53) is attached to the lower end of the intake distribution box (30). Cylinder engine intake system.

請求項１記載の多気筒エンジンの吸気装置において，
前記吸気分配箱（３０）の，前記第１及び第２バンク（６Ｌ，６Ｒ）間の谷間（２４）に臨む前壁に前記第１及び第２分岐管（３８Ｌ，３８Ｒ）を，これらが該吸気分配箱（３０）内に配置されるようにして一体に成形したことを特徴とする，多気筒エンジンの吸気装置。 The intake system for a multi-cylinder engine according to claim 1,
The first and second branch pipes (38L, 38R) are disposed on the front wall of the intake distribution box (30) facing the valley (24) between the first and second banks (6L, 6R). An intake device for a multi-cylinder engine, which is integrally formed so as to be disposed in an intake distribution box (30).