JP3906963B2 - Combustion chamber structure of internal combustion engine - Google Patents

Combustion chamber structure of internal combustion engine Download PDF

Info

Publication number
JP3906963B2
JP3906963B2 JP2000276984A JP2000276984A JP3906963B2 JP 3906963 B2 JP3906963 B2 JP 3906963B2 JP 2000276984 A JP2000276984 A JP 2000276984A JP 2000276984 A JP2000276984 A JP 2000276984A JP 3906963 B2 JP3906963 B2 JP 3906963B2
Authority
JP
Japan
Prior art keywords
valve
combustion chamber
intake
inclined surface
outer peripheral
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
JP2000276984A
Other languages
Japanese (ja)
Other versions
JP2002089266A (en
Inventor
裕介 和田
真一 渡部
史 佐藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Honda Motor Co Ltd
Original Assignee
Honda Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Honda Motor Co Ltd filed Critical Honda Motor Co Ltd
Priority to JP2000276984A priority Critical patent/JP3906963B2/en
Publication of JP2002089266A publication Critical patent/JP2002089266A/en
Application granted granted Critical
Publication of JP3906963B2 publication Critical patent/JP3906963B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0257—Independent control of two or more intake or exhaust valves respectively, i.e. one of two intake valves remains closed or is opened partially while the other is fully opened
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/08—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/0223—Variable control of the intake valves only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F1/42—Shape or arrangement of intake or exhaust channels in cylinder heads
    • F02F1/4214—Shape or arrangement of intake or exhaust channels in cylinder heads specially adapted for four or more valves per cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F2001/244—Arrangement of valve stems in cylinder heads
    • F02F2001/245—Arrangement of valve stems in cylinder heads the valve stems being orientated at an angle with the cylinder axis
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
  • Cylinder Crankcases Of Internal Combustion Engines (AREA)

Description

【０００１】
【発明の属す技術分野】
本発明は、４ストロークサイクル火花点火式内燃機関の燃焼室の構造に関するものである。
【０００２】
【従来技術および解決しようとする課題】
１対の吸気弁と１対の排気弁を備えた４ストロークサイクル火花点火式内燃機関において、圧縮比を増大させると、圧縮行程終期に点火栓による燃焼室内の混合気の着火で燃焼を始めた高圧の燃焼ガスにより、点火栓から離れた個所の混合気が高圧高温に加圧加熱され、火炎伝播によらず自己着火するノッキングが発生し易い。
【０００３】
このノッキングの発生を抑制するために燃焼室の下面を構成するピストン頂面の外周部がピストン中心軸方向に向いた上方へ緩やかに傾斜した外周***部を形成するとともに、燃焼室の上面を構成するシリンダヘッド内面を、外周部から中心に向い上方へ緩やかに傾斜した円錐面状に形成し、ピストンが上死点付近に接近した場合に、燃焼室の外周縁に上下巾の薄いスキッシュエリアから燃焼室中心に向いスキッシュ流を発生させるようにした燃焼室構造（特公平８−３０４１４号公報）があった。
【０００４】
しかし、燃焼室内の吸気弁付近は、新気や混合気の流入によって低温に冷却され、かつ排気弁より大径の吸気弁が存在して、充分なスキッシュエリアが確保されにくいため、圧縮行程終期における吸気弁付近の混合気では、他の部分の混合気よりも低温で火炎伝播速度が遅く、ノッキング発生の抑制効果が低かった。
【０００５】
これを改善するために、ピストン頂面の外周部における吸気弁付近に凹部となる切欠き部を形成し、ピストン頂面の外周部に隣接したスキッシュエリアで生成されたスキッシュ流がこの切り欠き部に流れ込み、この切り欠き部にてスキッシュ流を互いに衝突させることによって乱れを生成し、吸気弁付近での燃焼を促進した燃焼室構造（特開平１０−１８４３６６号公報）があった。
【０００６】
しかし、１対の吸気弁と１対の排気弁を備えた内燃機関では、充填効率を高水準に維持するために燃焼室外周縁と、燃焼室中心から最も離れた吸気弁外周縁部分との間隔が極めて狭くなっており、ピストン頂面の外周部における吸気弁近傍に隣接して形成された切り欠き部のシリンダ径方向の巾が著しく狭くなり、燃焼室内に局部的な過熱をもたらし、燃焼室内に部分的な切り欠き部を形成することでしかスキッシュ流の衝突効果を期待することができなかった。
【０００７】
【課題を解決するための手段および効果】
本出願発明は、このような難点を克服した内燃機関の燃焼室構造の改良に係り、請求項１の発明は、シリンダヘッドに１対の吸気弁と排気弁をそれぞれ備えたペントルーフ型燃焼室構造において、ピストン頂面の環状外周端面全周がピストン中心軸に対し直交する平面に形成されるとともに、該ピストン頂面の環状外周端面から中心寄り端面全周にシリンダヘッド方向へ突出する***部が形成され、かつ該***部にそれぞれ１対のバルブリセスが形成され、前記各***部における１対のバルブリセス間の頂面には、平面状傾斜面が形成されるとともに、該***部における各バルブリセス付近の頂面には、該平面状傾斜面に滑らかに接続するとともに、前記ピストン頂面の環状外周端面に滑らかに接続する円錐状傾斜面が形成され、前記１対のバルブリセス間における平面状傾斜面と環状外周端面で第１スキッシュエリアが形成されるとともに、円錐状傾斜面に第２スキッシュエリアが形成され、前記第１スキッシュエリアで生成されたスキッシュ流の少なくとも一部を前記第２スキッシュエリアに導くことを特徴とするものである。
【０００８】
請求項１の発明は、前述したように構成されているため、圧縮行程終期に、ピストンが上死点付近迄上昇し、ピストン頂面の環状外周端面と１対のバルブリセス間の平面状傾斜面とで第１スキッシュエリアが形成され、該第１スキッシュエリアから燃焼室中心に向ってスキッシュが流れ、燃焼室内の混合気が著しく撹乱され、また、前記第１スキッシュエリアの少なくとも一部のスキッシュ流が前記円錐状傾斜面に沿う第２スキッシュエリアを介して吸排気弁間の燃焼室外周部に噴射し、この吸気弁と排気弁の両方から噴射されるスキッシュ流の衝突で、燃焼室内の混合気に乱流が発生する。
【０００９】
第１スキッシュエリアと第２スキッシュエリアとで、このようにスキッシュエリアが広く構成されるため、燃焼室のコンパクト化が可能となり、また点火栓による着火火炎の伝播距離が短縮され、点火栓により着火された火炎が急速に燃焼室の外周円付近の未然混合気迄到着しうるので、自己着火する前に火炎によって着火され、ノッキングの発生が著しく抑制される。
【００１０】
また、第１スキッシュエリアから第２スキッシュエリアを介して吸排気弁間の燃焼室外周部にスキッシュ流をそれぞれ噴射して、相互に衝突させ、ノッキングを起し易い燃焼室外周部、特にバルブリセス近傍の混合気を充分に撹乱するため、ノッキングの発生をより一層確実に抑制できる。
【００１１】
さらに、請求項２のように発明を構成することにより、排気弁側のスキッシュエリアが吸気弁側のスキッシュエリアよりも広いため、排気弁側の第１スキッシュエリアから第２スキッシュエリアを介して吸排気弁間に噴射するスキッシュ流の方が、吸気弁側の第１スキッシュエリアから第２スキッシュエリアを介して吸排気弁間に噴射するスキッシュ流よりも強くなり、両者の衝突個所が吸気弁側に位置する結果、低温でノッキングを起し易い吸気弁近くの混合気が強く撹拌され、燃焼が促進されて、ノッキングの防止効果がさらに向上する。
【００１２】
さらにまた、請求項３のように発明を構成することにより、燃焼室中央の点火栓で着火された火炎が高さの低い吸排気弁間の***部を越えて燃焼室外周の吸排気弁間部に容易に到達でき、その火炎を相互に衝突させた吸排気弁間のスキッシュ流に着火させることで燃焼が促進され、燃焼室の外周における自己着火が未然に阻止される。
【００１３】
以下、図１ないし図７に図示された本発明の一実施形態について説明する。
４ストロークサイクル火花点火式内燃機関の燃焼室１は、シリンダブロック２のシリンダスリーブ３の内周面４と、シリンダブロック２の上方に一体に結合されたシリンダヘッド５の内面６と、シリンダスリーブ３の内周面４に摺動自在に嵌装されたピストン７の頂面８とで構成され、図１に図示されるように、前記シリンダヘッド５の内面６は、シリンダスリーブ３の中心軸の近くを通る稜線９を境にして左右上方へ緩やかに傾斜したペントルーフ形状に形成され、図３に図示されるように、一方の傾斜面に１対の吸気開口10が稜線９に沿って配設されるとともに他方の傾斜面に１対の排気開口11が同様に配設され、シリンダヘッド５では、これら吸気開口10および排気開口11にそれぞれ通ずる吸気ポート12および排気ポート13が形成されている。
【００１４】
また、前記シリンダヘッド５には、前記1対の吸気開口10および1対の排気開口11を開閉自在に密閉しうる吸気弁14および排気弁15が嵌装され、図示されないクランク軸に連結されたカムシャフトおよびロッカーアームなどの動弁機構により、前記吸気弁14および排気弁15はピストン７の昇降に連動して開閉駆動されるようになっている。
【００１５】
さらに、前記ピストン７の頂面８の環状外周端面16が、全周に亘り、ピストン７の中心軸に対し直交する平面すなわちシリンダブロック２とシリンダヘッド５との合せ面と平行な平面に形成されるとともに、該頂面８の環状外周端面16からピストン７の中心寄りに、シリンダヘッド５の方向へ緩やかな曲面で突出する***部17が形成され、該***部17に吸気弁14および排気弁15にそれぞれ対応した１対の吸気弁バルブリセス18、排気弁バルブリセス19が形成され、ピストン７の頂面８の中心部には、***部17により凹部20が形成されている。
【００１６】
そして、前記ピストン７の頂面８に形成された***部17では、１対の排気弁バルブリセス19の間の***部17Eの方が、１対の吸気弁バルブリセス18の間の***部17Iよりも高く形成され、両吸気弁バルブリセス18排気弁バルブリセス19の間の***部17Mが、前記***部17E、***部17Iよりも低く形成されている。
【００１７】
また、ピストン７の頂面８において、環状外周端面16から１対の吸気弁バルブリセス18の間の***部17Iの頂部***部17ITに亘り平面状傾斜面21Iが形成されるとともに、環状外周端面16から１対の排気弁バルブリセス19の間の***部17Eの頂部***部17ETに亘り平面状傾斜面21Eが形成されている。
【００１８】
さらに、ピストン７の頂面８において、環状外周端面16と吸気弁バルブリセス18と平面状傾斜面21Iとで囲まれた部分に円錐状傾斜面22Iが形成されるとともに、環状外周端面16と排気弁バルブリセス19と平面状傾斜面21Eとで囲まれた部分に円錐状傾斜面22Eが形成され、環状外周端面16と吸気弁バルブリセス18、排気弁バルブリセス19と***部17Mの頂部***部17MTとで囲まれた円周部分にも傾斜面23が形成されている。
【００１９】
さらにまた、シリンダヘッド５の内面６の略中央寄り燃焼室１内に点火栓24の電極部25が露出するように設けられ、しかも吸気ポート12に図示されない燃料噴射弁が設けられており、吸気行程で燃料噴射弁から燃料が噴射され、圧縮行程の終期に点火栓24の電極部25から火花が飛ばされるようになっている。
【００２０】
しかも、円錐状傾斜面22は、シリンダヘッド５の内面６に対し、平面状傾斜面21から傾斜面23に向けて除々に間隔が大きくなって、シリンダヘッド５の内面６に対する円錐状傾斜面22上の空間が広く形成され、平面状傾斜面21で生成されたスキッシュ流に指向性を持たせるようになっている。
【００２１】
そして、吸排気弁14，15とこれに対面するバルブリセ18，19の表面は平行なるように、バルブリセス18，19は形成されている。
【００２２】
図１ないし図７に図示の実施形態は前述したように構成されているので、圧縮行程終期において、ピストン７が上死点に接近すると、燃焼室１の周辺部の環状外周端面16、平面状傾斜面21I、平面状傾斜面21Eと、これに相対したシリンダヘッド５の内面６とで挟まれた空間が、図４に図示されるように狭くなって、この空間から燃焼室１の中央に向って図７の白抜き矢印のようにスキッシュ流が生ずるとともに、この空間から周方向に向う図７の点線白抜き矢印のようなスキッシュ流が生ずる。
【００２３】
また、これと同時に燃焼室１の周辺部の環状外周端面16、円錐状傾斜面22I、円錐状傾斜面22E、とこれに相対したシリンダヘッド５の内面６とで挟まれた空間も、図３に図示されるように狭くなり、この空間から周方向に向う図７の１点鎖線白抜き矢印のようなスキッシュ流が生じ、前記燃焼室１の周辺部環状外周端面16、平面状傾斜面21I、平面状傾斜面21Eとこれに相対したシリンダヘッド５の内面６とで挟まれて発生した周方向スキッシュ流と合流し、環状外周端面16と吸気弁バルブリセス18、排気弁バルブリセス19と***部17Mの頂部***部17MTとで囲まれた傾斜面23に沿い周方向へ流れる。この傾斜面23に沿い吸気弁バルブリセス18から流れた周方向スキッシュ流と、傾斜面23に沿い、排気弁バルブリセス19から流れた周方向スキッシュ流は、傾斜面23の周方向中央部で衝突を起し、乱れる。そして、これらの周方向スキッシュ流は、上方へ盛った傾斜面23によって燃焼室１の中心に向きを変えずに環状外周端面16上を進行するため、前記衝突による乱れは激しいものである。
【００２４】
さらに、円錐状傾斜面22は、シリンダヘッド５の内面６に対し、平面状傾斜21から傾斜面23に向けて除々に空間が広がるように形成されているため、平面状傾斜面21で生成されたスキッシュ流の内、周方向に流れるスキッシュ流に周方向の指向性を持たせている結果、前記衝突がさらに強化される。
【００２５】
このように、図示の実施形態では、燃焼室１の周辺部全周に亘りスキッシュ流が生じて、スキッシュエリアが広く形成されるため、燃焼室１の燃焼領域がコンパクト化され、点火栓24による着火火炎の伝播距離が短縮され、また、点火栓24により着火された火炎が急速に燃焼室１の周縁部の未然混合気迄伝播するので、自己着火する前に、火炎によって着火され、ノッキングの発生が抑制される。この結果、圧縮比の増大が可能となって、燃費の改善を促進することができる。
【００２６】
また、１対の吸気弁14の内の一方を休止させることにより、吸気行程における燃焼室１内のスワールを強化でき、逆スキッシュおよびスキッシュとの組合せの相乗効果を増強して、燃焼室１内の混合気を強く乱すことができる。
同様に、吸気ポート12を螺旋状に形成してスワールを発生してもよい。
【００２７】
さらに、ピストン７の頂面８はおよびシリンダヘッド５の内面６は、滑らかな曲面に形成されているため、膨張行程で得られる燃焼室内のスワール流を圧縮行程で減衰させることなくスキッシュと組合せて燃焼室１内の混合気を強く乱すことができ、また燃焼室１内の局部的な過熱による自己着火をも抑制することができる。
【００２８】
さらにまた、ピストン７の頂面８における傾斜面23と、シリンダヘッド５の内面６におけるこの部位に対応した部分との間のスキッシュエリアが存在しない領域でも、図７に図示される1点鎖線白抜き矢印に図示されるような周方向スキッシュ流を導き、この領域で、相互に衝突させて、大きな乱れを発生することができ、また、シリンダヘッド５の内面６とピストン７の頂面８における環状外周端面16は、自己着火および火炎伝播の減衰を招く断面鋭角部分が存在しないことより、ノッキングの抑制効果を著しく向上させることができる。
【００２９】
しかも、前記ピストン７の頂面８に形成された***部17において、１対の排気弁バルブリセス19間の***部17Eの方を、１対の吸気弁バルブリセス18間の***部17Iよりも高く形成しているため、１対の排気弁バルブリセス19間の***部17Eにおける平面状傾斜面21Eに接したスキッシュエリアを、１対の吸気弁バルブリセス18間の***部17Iにおける平面状傾斜面21Iに接したスキッシュエリアよりも広く形成し、平面状傾斜面21Eに接したスキッシュエリアからのスキッシュ流を***部17Iの方へ強く導くことができる。
【００３０】
また、吸排気弁14，15とこれに対面するバルブリセス18，19の表面は互いに平行にすることにより、特にピストン上死点における吸気弁14周り（周辺）の容積を少なく形成でき、これによって吸入行程、ピストン下降に伴なう吸気弁14周りの圧力を低く設定でき、吸気ポートからの吸気が入りやすい状態とされる。よって吸気における体積効率を向上させることができる。
【図面の簡単な説明】
【図１】本発明に係る燃焼室構造におけるシリンダヘッド内面の形状を図示した概略斜視図である。
【図２】図１に図示の燃焼室構造のピストン頂面の形状を図示した概略斜視図である。
【図３】点火栓を除去した状態で図２のIII−III線に沿って裁断した縦断面図である。
【図４】図２のIV−IV線に沿って裁断した縦断面図である。
【図５】図２のＶ−Ｖ線に沿って裁断した縦断面図である。
【図６】シリンダヘッド内面とピストン頂面を合わせた平面図である。
【図７】ピストン頂面の平面図である。
【符号の説明】
１…燃焼室、２…シリンダブロック、３…シリンダスリーブ、４…内周面、５…シリンダヘッド、６…内面、７…ピストン、８…頂面、９…稜線、10…吸気開口、11…排気開口、12…吸気ポート、13…排気ポート、14…吸気弁、15…排気弁、16…環状外周端面、17…***部、18…吸気弁バルブリセス、19…排気弁、20…凹部、21…平面状傾斜面、22…円錐状傾斜面、23…傾斜面、24…点火栓、25…電極部。[0001]
[Technical Field]
The present invention relates to the structure of a combustion chamber of a four-stroke cycle spark ignition internal combustion engine.
[0002]
[Prior art and problems to be solved]
In a 4-stroke cycle spark ignition internal combustion engine equipped with a pair of intake valves and a pair of exhaust valves, when the compression ratio was increased, combustion started by ignition of the air-fuel mixture in the combustion chamber by the spark plug at the end of the compression stroke. Due to the high-pressure combustion gas, the air-fuel mixture at a location away from the spark plug is pressurized and heated to a high pressure and high temperature, and knocking that self-ignites easily occurs regardless of flame propagation.
[0003]
In order to suppress the occurrence of this knocking, the outer peripheral portion of the piston top surface constituting the lower surface of the combustion chamber forms an outer peripheral bulging portion that gently slopes upward in the direction of the piston central axis, and configures the upper surface of the combustion chamber The inner surface of the cylinder head is formed into a conical surface that is gently inclined upward from the outer periphery toward the center, and when the piston approaches the top dead center, a thin squish area is formed on the outer periphery of the combustion chamber. There was a combustion chamber structure (Japanese Patent Publication No. 8-30414) in which a squish flow was generated toward the center of the combustion chamber.
[0004]
However, the vicinity of the intake valve in the combustion chamber is cooled to a low temperature by the inflow of fresh air or air-fuel mixture, and there is an intake valve larger in diameter than the exhaust valve, making it difficult to secure a sufficient squish area. In the air-fuel mixture in the vicinity of the intake valve, the flame propagation speed was slower at the lower temperature than in the other air-fuel mixture, and the effect of suppressing the occurrence of knocking was low.
[0005]
In order to improve this, a notch that becomes a recess is formed in the vicinity of the intake valve in the outer peripheral portion of the piston top surface, and the squish flow generated in the squish area adjacent to the outer periphery of the piston top surface is the notch. There is a combustion chamber structure (Japanese Patent Laid-Open No. 10-184366) in which turbulence is generated by causing the squish flow to collide with each other at this notch, and combustion near the intake valve is promoted.
[0006]
However, in an internal combustion engine provided with a pair of intake valves and a pair of exhaust valves, the distance between the outer peripheral edge of the combustion chamber and the outer peripheral edge portion of the intake valve farthest from the center of the combustion chamber in order to maintain the charging efficiency at a high level. Is extremely narrow, and the width in the cylinder radial direction of the notch formed adjacent to the vicinity of the intake valve in the outer peripheral portion of the piston top surface is remarkably narrow, resulting in local overheating in the combustion chamber, The impact effect of the squish flow could only be expected by forming a partial notch.
[0007]
[Means for solving the problems and effects]
The present invention relates to an improvement in the combustion chamber structure of an internal combustion engine that has overcome such difficulties, and the invention of claim 1 is a pent roof type combustion chamber structure in which a cylinder head is provided with a pair of intake valves and exhaust valves, respectively. In addition, the entire circumference of the annular outer peripheral end surface of the piston top surface is formed in a plane orthogonal to the piston central axis, and a protruding portion that protrudes in the direction of the cylinder head from the annular outer peripheral end surface of the piston top surface to the entire center end surface. And a pair of valve recesses are formed in the raised portions, and a flat inclined surface is formed on the top surface between the pair of valve recesses in each raised portion, and in the vicinity of each valve recess in the raised portion. A conical inclined surface that is smoothly connected to the planar inclined surface and smoothly connected to the annular outer peripheral end surface of the piston top surface is formed on the top surface of At least a part of the squish flow generated in the first squish area, the first squish area is formed by the planar inclined surface and the annular outer peripheral end surface between the lubricious parts, and the second squish area is formed on the conical inclined surface. Is guided to the second squish area.
[0008]
Since the invention of claim 1 is configured as described above, at the end of the compression stroke, the piston rises to near the top dead center, and a planar inclined surface between the annular outer peripheral end surface of the piston top surface and the pair of valve recesses. The first squish area is formed, the squish flows from the first squish area toward the center of the combustion chamber, the air-fuel mixture in the combustion chamber is significantly disturbed, and at least a part of the squish flow in the first squish area Is injected into the outer peripheral portion of the combustion chamber between the intake and exhaust valves via the second squish area along the conical inclined surface, and the mixing in the combustion chamber is caused by the collision of the squish flow injected from both the intake valve and the exhaust valve. Turbulence occurs.
[0009]
Since the first squish area and the second squish area are configured in this manner, the combustion chamber can be made compact, the propagation distance of the ignition flame by the spark plug is shortened, and the ignition plug ignites. Since the generated flame can quickly reach the air-fuel mixture near the outer circumference of the combustion chamber, it is ignited by the flame before self-ignition and the occurrence of knocking is remarkably suppressed.
[0010]
In addition, a squish flow is injected from the first squish area to the outer periphery of the combustion chamber between the intake and exhaust valves through the second squish area, causing the squish flow to collide with each other and causing knocking, particularly in the vicinity of the valve recess. Therefore, the occurrence of knocking can be more reliably suppressed.
[0011]
Further, by configuring the invention as in claim 2, the squish area on the exhaust valve side is wider than the squish area on the intake valve side, so that suction is performed from the first squish area on the exhaust valve side through the second squish area. The squish flow injected between the exhaust valves is stronger than the squish flow injected between the intake and exhaust valves from the first squish area on the intake valve side through the second squish area, and the collision point between the two is on the intake valve side. As a result, the air-fuel mixture near the intake valve, which is likely to cause knocking at a low temperature, is agitated strongly, combustion is promoted, and the effect of preventing knocking is further improved.
[0012]
Furthermore, by configuring the invention as in claim 3, the flame ignited by the spark plug at the center of the combustion chamber passes over the raised portion between the intake and exhaust valves having a low height, and between the intake and exhaust valves on the outer periphery of the combustion chamber. Combustion is facilitated by igniting the squish flow between the intake and exhaust valves that collide with each other and the flames collide with each other, and self-ignition on the outer periphery of the combustion chamber is prevented in advance.
[0013]
Hereinafter, an embodiment of the present invention illustrated in FIGS. 1 to 7 will be described.
A combustion chamber 1 of a four-stroke cycle spark ignition type internal combustion engine includes an inner peripheral surface 4 of a cylinder sleeve 3 of a cylinder block 2, an inner surface 6 of a cylinder head 5 integrally coupled above the cylinder block 2, and a cylinder sleeve 3. 1 and a top surface 8 of a piston 7 slidably fitted on the inner peripheral surface 4 of the cylinder. As shown in FIG. It is formed in a pent roof shape that is gently inclined upward and leftward with a ridgeline 9 passing through as a boundary, and a pair of intake openings 10 are arranged along the ridgeline 9 on one inclined surface as shown in FIG. In addition, a pair of exhaust openings 11 are similarly arranged on the other inclined surface, and the cylinder head 5 has an intake port 12 and an exhaust port 13 communicating with the intake opening 10 and the exhaust opening 11, respectively. .
[0014]
The cylinder head 5 is fitted with an intake valve 14 and an exhaust valve 15 that are capable of opening and closing the pair of intake openings 10 and the pair of exhaust openings 11 so as to be freely opened and closed, and connected to a crankshaft (not shown). The intake valve 14 and the exhaust valve 15 are driven to open and close in conjunction with the elevation of the piston 7 by a valve operating mechanism such as a camshaft and a rocker arm.
[0015]
Further, the annular outer peripheral end surface 16 of the top surface 8 of the piston 7 is formed on a plane perpendicular to the central axis of the piston 7 over the entire circumference, that is, a plane parallel to the mating surface of the cylinder block 2 and the cylinder head 5. In addition, a bulging portion 17 protruding from the annular outer peripheral end surface 16 of the top surface 8 toward the cylinder head 5 with a gently curved surface is formed near the center of the piston 7, and an intake valve 14 and an exhaust valve are formed on the bulging portion 17. A pair of intake valve valve recesses 18 and exhaust valve valve recesses 19 corresponding to 15 are formed, and a recess 20 is formed in the center of the top surface 8 of the piston 7 by a raised portion 17.
[0016]
In the raised portion 17 formed on the top surface 8 of the piston 7, the raised portion 17 E between the pair of exhaust valve valve recesses 19 is higher than the raised portion 17 I between the pair of intake valve valve recesses 18. The raised portion 17 M between the intake valve valve recess 18 and the exhaust valve recess 19 is formed lower than the raised portion 17 E and the raised portion 17 I.
[0017]
Further, on the top surface 8 of the piston 7, a planar inclined surface 21 I is formed from the annular outer peripheral end surface 16 to the top bulging portion 17 IT of the bulging portion 17 I between the pair of intake valve valve recesses 18. A planar inclined surface 21 E is formed from the outer peripheral end surface 16 to the top raised portion 17 ET of the raised portion 17 E between the pair of exhaust valve valve recesses 19.
[0018]
Further, on the top surface 8 of the piston 7, a conical inclined surface 22 I is formed in a portion surrounded by the annular outer peripheral end surface 16, the intake valve valve recess 18 and the planar inclined surface 21 I, and the annular outer peripheral end surface 16 A conical inclined surface 22 E is formed in a part surrounded by the exhaust valve valve recess 19 and the flat inclined surface 21 E, and the top end of the annular outer peripheral end surface 16 and the intake valve valve recess 18, the exhaust valve valve recess 19 and the raised portion 17 M. An inclined surface 23 is also formed in a circumferential portion surrounded by the portion 17 MT .
[0019]
Further, an electrode portion 25 of the spark plug 24 is provided in the combustion chamber 1 substantially near the center of the inner surface 6 of the cylinder head 5, and a fuel injection valve (not shown) is provided in the intake port 12. Fuel is injected from the fuel injection valve in the stroke, and a spark is blown from the electrode portion 25 of the spark plug 24 at the end of the compression stroke.
[0020]
In addition, the conical inclined surface 22 gradually increases from the flat inclined surface 21 toward the inclined surface 23 with respect to the inner surface 6 of the cylinder head 5, and the conical inclined surface 22 with respect to the inner surface 6 of the cylinder head 5. The upper space is widely formed so that the squish flow generated by the planar inclined surface 21 has directivity.
[0021]
The valve recesses 18 and 19 are formed so that the intake and exhaust valves 14 and 15 and the surfaces of the valve recesses 18 and 19 facing the intake and exhaust valves 14 and 15 are parallel to each other.
[0022]
Since the embodiment shown in FIGS. 1 to 7 is configured as described above, when the piston 7 approaches the top dead center at the end of the compression stroke, the annular outer peripheral end surface 16 of the peripheral portion of the combustion chamber 1 is planar. A space sandwiched between the inclined surface 21 I , the planar inclined surface 21 E, and the inner surface 6 of the cylinder head 5 opposite to the inclined surface 21 I becomes narrow as shown in FIG. A squish flow is generated as indicated by a white arrow in FIG. 7 toward the center, and a squish flow as indicated by a dotted white arrow in FIG.
[0023]
At the same time, a space sandwiched between the annular outer peripheral end surface 16, the conical inclined surface 22 I and the conical inclined surface 22 E on the periphery of the combustion chamber 1 and the inner surface 6 of the cylinder head 5 opposite thereto is also provided. As shown in FIG. 3, a squish flow such as the one-dot chain line white arrow in FIG. 7 that narrows toward the circumferential direction from this space is generated, and the peripheral annular outer peripheral end face 16 of the combustion chamber 1 has a planar inclination. The circumferential squish flow generated between the surface 21 I , the plane inclined surface 21 E and the inner surface 6 of the cylinder head 5 opposed to the surface 21 I merges, and the annular outer peripheral end surface 16, the intake valve valve recess 18, and the exhaust valve valve recess 19. and it flows into along the circumferential direction on the inclined surface 23 surrounded by the top ridges 17 MT of the ridges 17 M. The circumferential squish flow that flows from the intake valve valve recess 18 along the inclined surface 23 and the circumferential squish flow that flows from the exhaust valve valve recess 19 along the inclined surface 23 cause a collision at the circumferential center of the inclined surface 23. And disturbed. These circumferential squish flows travel on the annular outer peripheral end face 16 without changing the direction toward the center of the combustion chamber 1 by the inclined surface 23 that is raised upward, so that the disturbance due to the collision is severe.
[0024]
Further, the conical inclined surface 22 is formed on the inner surface 6 of the cylinder head 5 so that the space gradually increases from the planar inclined surface 21 toward the inclined surface 23, so that it is generated by the planar inclined surface 21. Of the squish flows, the squish flow that flows in the circumferential direction is given directionality in the circumferential direction, so that the collision is further strengthened.
[0025]
As described above, in the illustrated embodiment, a squish flow is generated over the entire periphery of the periphery of the combustion chamber 1 to form a wide squish area. The propagation distance of the ignition flame is shortened, and the flame ignited by the spark plug 24 quickly propagates to the air-fuel mixture at the peripheral edge of the combustion chamber 1, so that it is ignited by the flame and knocked before self-ignition. Occurrence is suppressed. As a result, the compression ratio can be increased, and the improvement of fuel consumption can be promoted.
[0026]
Also, by suspending one of the pair of intake valves 14, the swirl in the combustion chamber 1 in the intake stroke can be strengthened, and the synergistic effect of the combination with reverse squish and squish is enhanced, and the combustion chamber 1 The air-fuel mixture can be strongly disturbed.
Similarly, the swirl may be generated by forming the intake port 12 in a spiral shape.
[0027]
Furthermore, since the top surface 8 of the piston 7 and the inner surface 6 of the cylinder head 5 are formed in a smooth curved surface, the swirl flow in the combustion chamber obtained in the expansion stroke is combined with the squish without being attenuated in the compression stroke. The air-fuel mixture in the combustion chamber 1 can be strongly disturbed, and self-ignition due to local overheating in the combustion chamber 1 can also be suppressed.
[0028]
Furthermore, even in a region where there is no squish area between the inclined surface 23 on the top surface 8 of the piston 7 and the portion corresponding to this portion on the inner surface 6 of the cylinder head 5, the alternate long and short dash line shown in FIG. A circumferential squish flow as shown in the drawing arrow can be guided and collided with each other in this region to generate a large turbulence, and also on the inner surface 6 of the cylinder head 5 and the top surface 8 of the piston 7. Since the annular outer peripheral end face 16 does not have an acute angle section that causes self-ignition and attenuation of flame propagation, the effect of suppressing knocking can be remarkably improved.
[0029]
Moreover, in the raised portion 17 formed on the top surface 8 of the piston 7, the raised portion 17 E between the pair of exhaust valve valve recesses 19 is more than the raised portion 17 I between the pair of intake valve valve recesses 18. Since it is formed high, the squish area in contact with the planar inclined surface 21 E in the raised portion 17 E between the pair of exhaust valve valve recesses 19 is formed in the planar shape in the raised portion 17 I between the pair of intake valve valve recesses 18. It is formed wider than the squish area in contact with the inclined surface 21 I , and the squish flow from the squish area in contact with the planar inclined surface 21 E can be strongly guided toward the raised portion 17 I.
[0030]
In addition, by making the surfaces of the intake and exhaust valves 14 and 15 and the valve recesses 18 and 19 facing them parallel to each other, the volume around the intake valve 14 (periphery) particularly at the top dead center of the piston can be reduced, thereby The pressure around the intake valve 14 associated with the stroke and the lowering of the piston can be set low, and the intake air from the intake port can easily enter. Therefore, the volume efficiency in intake can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view illustrating the shape of an inner surface of a cylinder head in a combustion chamber structure according to the present invention.
2 is a schematic perspective view illustrating the shape of a piston top surface of the combustion chamber structure illustrated in FIG. 1; FIG.
3 is a longitudinal sectional view cut along line III-III in FIG. 2 with the spark plug removed. FIG.
4 is a longitudinal sectional view cut along a line IV-IV in FIG. 2;
5 is a longitudinal sectional view cut along a line VV in FIG. 2. FIG.
FIG. 6 is a plan view of a cylinder head inner surface and a piston top surface combined.
FIG. 7 is a plan view of a piston top surface.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Combustion chamber, 2 ... Cylinder block, 3 ... Cylinder sleeve, 4 ... Inner peripheral surface, 5 ... Cylinder head, 6 ... Inner surface, 7 ... Piston, 8 ... Top surface, 9 ... Ridge line, 10 ... Intake opening, 11 ... Exhaust opening, 12 ... intake port, 13 ... exhaust port, 14 ... intake valve, 15 ... exhaust valve, 16 ... annular outer peripheral end face, 17 ... raised portion, 18 ... intake valve valve recess, 19 ... exhaust valve, 20 ... recess, 21 ... planar inclined surface, 22 ... conical inclined surface, 23 ... inclined surface, 24 ... spark plug, 25 ... electrode part.

Claims (3)

シリンダヘッドに１対の吸気弁と排気弁をそれぞれ備えたペントルーフ型燃焼室構造において、
ピストン頂面の環状外周端面全周がピストン中心軸に対し直交する平面に形成されるとともに、該ピストン頂面の環状外周端面から中心寄り端面全周にシリンダヘッド方向へ突出する***部が形成され、かつ該***部にそれぞれ１対のバルブリセスが形成され、
前記各***部における１対のバルブリセス間の頂面には、平面状傾斜面が形成されるとともに、該***部における各バルブリセス付近の頂面には、該平面状傾斜面に滑らかに接続するとともに、前記ピストン頂面の環状外周端面に滑らかに接続する円錐状傾斜面が形成され、
前記１対のバルブリセス間における平面状傾斜面と環状外周端面で第１スキッシュエリアが形成されるとともに、円錐状傾斜面に第２スキッシュエリアが形成され、前記第１スキッシュエリアで生成されたスキッシュ流の少なくとも一部を前記第２スキッシュエリアに導くことを特徴とする内燃機関の燃焼室構造。In a pent roof type combustion chamber structure having a pair of intake and exhaust valves in the cylinder head,
The entire circumference of the annular outer peripheral end surface of the piston top surface is formed in a plane orthogonal to the piston central axis, and a raised portion that protrudes from the annular outer peripheral end surface of the piston top surface to the entire center end surface in the direction of the cylinder head is formed. And a pair of valve recesses is formed on each of the raised portions,
A flat inclined surface is formed on the top surface between the pair of valve recesses in each raised portion, and the top surface in the vicinity of each valve recess in the raised portion is smoothly connected to the planar inclined surface. , A conical inclined surface that is smoothly connected to the annular outer peripheral end surface of the piston top surface is formed,
A first squish area is formed by the planar inclined surface and the annular outer peripheral end surface between the pair of valve recesses, and a second squish area is formed on the conical inclined surface, and the squish flow generated in the first squish area is formed. A combustion chamber structure for an internal combustion engine, wherein at least a part of the engine is guided to the second squish area. 請求項１記載の内燃機関の燃焼室構造において、前記排気側のスキッシュエリアが、前記吸気側のスキッシュエリアより広く形成されたことを特徴とする内燃機関の燃焼室構造。  2. A combustion chamber structure for an internal combustion engine according to claim 1, wherein the exhaust-side squish area is formed wider than the intake-side squish area. 請求項１記載の内燃機関の燃焼室構造において、前記吸気弁および排気弁におけるそれぞれのバルブリセス間の***部の高さは、前記吸気弁および排気弁間の***部高さよりも高く形成されたことを特徴とする内燃機関の燃焼室構造。2. The combustion chamber structure of the internal combustion engine according to claim 1, wherein a height of a raised portion between each valve recess in the intake valve and the exhaust valve is formed higher than a height of a raised portion between the intake valve and the exhaust valve. A combustion chamber structure for an internal combustion engine.
JP2000276984A 2000-09-12 2000-09-12 Combustion chamber structure of internal combustion engine Expired - Fee Related JP3906963B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2000276984A JP3906963B2 (en) 2000-09-12 2000-09-12 Combustion chamber structure of internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2000276984A JP3906963B2 (en) 2000-09-12 2000-09-12 Combustion chamber structure of internal combustion engine

Publications (2)

Publication Number Publication Date
JP2002089266A JP2002089266A (en) 2002-03-27
JP3906963B2 true JP3906963B2 (en) 2007-04-18

Family

ID=18762372

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2000276984A Expired - Fee Related JP3906963B2 (en) 2000-09-12 2000-09-12 Combustion chamber structure of internal combustion engine

Country Status (1)

Country Link
JP (1) JP3906963B2 (en)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3769251B2 (en) 2002-08-28 2006-04-19 本田技研工業株式会社 Combustion chamber structure of internal combustion engine
TWI290191B (en) * 2003-10-24 2007-11-21 Mitsubishi Motors Corp Combustion chamber structure in an internal combustion engine
FR2864152B1 (en) * 2003-12-23 2007-11-23 Renault Sas MOTOR FOR VEHICLE COMPRISING AT LEAST ONE PISTON DEFINING A COMBUSTION CHAMBER
JP4280925B2 (en) * 2004-12-27 2009-06-17 三菱自動車エンジニアリング株式会社 Combustion chamber structure of internal combustion engine
DE102005002389B4 (en) * 2005-01-19 2009-04-23 Fev Motorentechnik Gmbh Vehicle piston internal combustion engine with adapted trough
JP4851864B2 (en) 2006-06-23 2012-01-11 本田技研工業株式会社 Direct fuel injection diesel engine
DE102007027787A1 (en) * 2007-06-16 2008-12-18 GM Global Technology Operations, Inc., Detroit Internal combustion engine with charge turbulence
JP5652466B2 (en) * 2012-12-21 2015-01-14 トヨタ自動車株式会社 Piston for internal combustion engine and internal combustion engine
JP7260331B2 (en) * 2019-02-27 2023-04-18 ダイハツ工業株式会社 Internal combustion engine with auxiliary combustion chamber
CN111456865A (en) * 2020-04-09 2020-07-28 南京尚德柴油机有限公司 Internal combustion engine piston and internal combustion engine
CN114991943A (en) * 2021-03-01 2022-09-02 比亚迪股份有限公司 Engine and vehicle with same

Also Published As

Publication number Publication date
JP2002089266A (en) 2002-03-27

Similar Documents

Publication Publication Date Title
US6209514B1 (en) Direct injection gasoline engine
JP2597657B2 (en) Combustion chamber of internal combustion engine
US6928997B2 (en) Direct injection engine
JP7388224B2 (en) Internal combustion engine with prechamber
JP2002188448A (en) Cylinder fuel injection type gasoline engine where fuel is injected inside the cylinder
JP3906963B2 (en) Combustion chamber structure of internal combustion engine
JPS5845571B2 (en) Combustion chamber of internal combustion engine
JP2002129962A (en) Piston for in-cylinder injection engine
JP6508240B2 (en) Spark-ignition type internal combustion engine
JP6747573B2 (en) Intake port structure of internal combustion engine
JPH10317975A (en) Direct cylinder injection spark ignition engine
US6701883B2 (en) Cylinder head for use on a spark-ignition internal combustion engine and such spark-ignition internal combustion engine
JP6750724B2 (en) Intake port structure of internal combustion engine
JP4438726B2 (en) Combustion chamber structure of spark ignition engine
JP2018162726A (en) Spark ignition type internal combustion engine
JP4020792B2 (en) In-cylinder internal combustion engine
JP6515942B2 (en) Spark-ignition type internal combustion engine
JP3775038B2 (en) In-cylinder injection spark ignition internal combustion engine piston
JP3817910B2 (en) Piston for in-cylinder internal combustion engine
JP3852273B2 (en) Combustion chamber of internal combustion engine
JPS5821090B2 (en) air injection gasoline engine
JP4257520B2 (en) In-cylinder internal combustion engine
JP3721761B2 (en) Piston for in-cylinder internal combustion engine
JPH11182249A (en) Direct injection spark-ignition type internal combustion engine
JPH07116945B2 (en) Spark ignition engine combustion chamber

Legal Events

Date Code Title Description
A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20060612

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20060621

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20060808

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20070110

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20070110

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

Ref document number: 3906963

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100126

Year of fee payment: 3

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110126

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110126

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120126

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120126

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130126

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130126

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140126

Year of fee payment: 7

LAPS Cancellation because of no payment of annual fees