JPH0868330A - Structure of piston having auxiliary chamber - Google Patents

Structure of piston having auxiliary chamber

Info

Publication number
JPH0868330A
JPH0868330A JP6224008A JP22400894A JPH0868330A JP H0868330 A JPH0868330 A JP H0868330A JP 6224008 A JP6224008 A JP 6224008A JP 22400894 A JP22400894 A JP 22400894A JP H0868330 A JPH0868330 A JP H0868330A
Authority
JP
Japan
Prior art keywords
piston
chamber
sub
sub chamber
thermal expansion
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.)
Pending
Application number
JP6224008A
Other languages
Japanese (ja)
Inventor
Hiroshi Matsuoka
寛 松岡
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.)
Isuzu Motors Ltd
Original Assignee
Isuzu Motors 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 Isuzu Motors Ltd filed Critical Isuzu Motors Ltd
Priority to JP6224008A priority Critical patent/JPH0868330A/en
Publication of JPH0868330A publication Critical patent/JPH0868330A/en
Pending legal-status Critical Current

Links

Classifications

    • 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
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0618—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston having in-cylinder means to influence the charge motion
    • F02B23/0627—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston having in-cylinder means to influence the charge motion having additional bores or grooves machined into the piston for guiding air or charge flow to the piston bowl
    • 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
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0603—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston at least part of the interior volume or the wall of the combustion space being made of material different from the surrounding piston part, e.g. combustion space formed within a ceramic part fixed to a metal piston head
    • 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
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0633—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston the combustion space being almost completely enclosed in the piston, i.e. having a small inlet in comparison to its volume
    • 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
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0636—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston the combustion space having a substantially flat and horizontal bottom
    • 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
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0675—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston the combustion space being substantially spherical, hemispherical, ellipsoid or parabolic
    • 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
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0603—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston at least part of the interior volume or the wall of the combustion space being made of material different from the surrounding piston part, e.g. combustion space formed within a ceramic part fixed to a metal piston head
    • F02B2023/0612—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston at least part of the interior volume or the wall of the combustion space being made of material different from the surrounding piston part, e.g. combustion space formed within a ceramic part fixed to a metal piston head the material having a high temperature and pressure resistance, e.g. ceramic
    • 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
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/14—Direct injection into combustion chamber
    • 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
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
    • 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)
  • Ceramic Engineering (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)

Abstract

PURPOSE: To increase connecting force between a piston main body and an auxiliary chamber structure for constituting an auxiliary chamber, and also improve heat insulating property, in the structure of a piston having the auxiliary chamber. CONSTITUTION: A piston having an auxiliary chamber is arranged on a metal made piston main body by casting an auxiliary chamber structure 8 for forming an auxiliary chamber 2. The auxiliary chamber structure 8 is made of heat resistance alloy such as an incoloy 903 having low heat expansion, the outer wall surface 16 of the auxiliary chamber structure 8 and the wall surface 17 of the cavity of the piston main body 4 are connected to each other by a connecting members 19, 20 having heat expansion coefficient which are provided between the piston main body 4 and the auxiliary chamber structure 8. A heat insulating material 21 is arranged between the auxiliary structure 8 and the piston main body 4.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】この発明は、ピストン本体のほぼ
中央に副室を形成した副室構造体を耐熱材料で作製した
副室を持つピストンの構造に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a piston having a sub-chamber made of a heat-resistant material for a sub-chamber structure in which a sub-chamber is formed substantially at the center of a piston body.

【０００２】[0002]

【従来の技術】従来、実開昭６０−１００５２８号公報
には直接噴射式ディーゼルエンジン用ピストンが開示さ
れている。該直接噴射式ディーゼルエンジン用ピストン
は、ピストン頂部に穿設された燃焼室の開口部に、この
開口部を閉塞する閉塞部材を設け、前記燃焼室内に渦流
を発生させる方向に向かい、燃料噴射ノズルから噴射さ
れる燃料の噴出方向と略平行に前記燃焼室とシリンダ室
とを連通する燃料噴射通路を前記閉塞部材に設けたもの
である。2. Description of the Related Art Conventionally, Japanese Unexamined Utility Model Publication No. 60-100528 discloses a piston for a direct injection diesel engine. The piston for a direct injection diesel engine is provided with a closing member for closing the opening of a combustion chamber formed at the top of the piston, the closing member closing the opening to face a direction for generating a vortex in the combustion chamber, and a fuel injection nozzle. A fuel injection passage that connects the combustion chamber and the cylinder chamber to each other is provided in the closing member in a direction substantially parallel to the ejection direction of the fuel injected from.

【０００３】また、実開昭６０−１４１４４６号公報に
はセラミック組込型ピストンが開示されている。該セラ
ミック組込型ピストンは、セラミック部材の外周に耐熱
耐食性金属リングを接合した組立体を作り、該組立体を
アルミニウム合金から成るピストン本体に螺着してピス
トン本体の燃焼室側の凹部にセラミック部材を組み込ん
だものである。Further, Japanese Utility Model Publication No. 60-141446 discloses a ceramic built-in piston. The ceramic-embedded piston is formed by assembling a heat-resistant and corrosion-resistant metal ring on the outer periphery of a ceramic member, and the assembly is screwed to a piston body made of an aluminum alloy to form a ceramic in a recess on the combustion chamber side of the piston body. It is one that incorporates members.

【０００４】また、特開昭６３−１０９２６７号公報に
は内燃機関のピストンが開示されている。該内燃機関の
ピストンは、ピストン本体と該ピストン本体の上部に鋳
ぐるまれるセラミック製キャビティ部材とを有し、セラ
ミックファイバーの成形体に無機材が付与されてなる断
熱層をキャビティ部材の外表面を被覆した状態でピスト
ン本体に鋳ぐるんだものである。Further, Japanese Patent Laid-Open No. 63-109267 discloses a piston for an internal combustion engine. The piston of the internal combustion engine has a piston body and a ceramic cavity member that is cast on the upper portion of the piston body, and an insulating layer formed by adding an inorganic material to a ceramic fiber molded body is provided on the outer surface of the cavity member. It is cast around the piston body in the state of being coated with.

【０００５】[0005]

【発明が解決しようとする課題】一般に、副室での燃焼
温度は高温であるため、ＮＯX の生成を低減する対策と
しては、燃料リッチで燃焼させることが効果的である。
また、燃焼温度が高温である時、燃料リッチで燃焼させ
るには、エンジン構造のタイプとしては副室式エンジン
で対応することが有効である。エンジンを副室式燃焼室
に構成した場合に、副室式燃焼室の燃焼スピードを直接
噴射式燃焼室の燃焼スピードと同程度まで速くするに
は、副室と主室とを連通する連通孔の通路断面積を拡大
することが必要である。ところが、連通孔の通路断面積
を大きくすると、副室から主室へ流出する噴出スピード
が低下し、主室での燃焼が十分に行われない。To the 0005] Generally, the combustion temperature in the secondary chamber because of the high temperature, as a measure to reduce the production of NO X, it is effective to combust the fuel-rich.
When the combustion temperature is high, it is effective to use a sub-chamber engine as a type of engine structure in order to burn the fuel rich. When the engine is configured as a sub-chamber combustion chamber, in order to increase the combustion speed of the sub-chamber combustion chamber to the same level as the combustion speed of the direct injection combustion chamber, a communication hole that connects the sub-chamber to the main chamber It is necessary to increase the cross-sectional area of the passage. However, when the passage cross-sectional area of the communication hole is increased, the ejection speed of the sub-chamber outflowing to the main chamber is reduced, and combustion in the main chamber is not sufficiently performed.

【０００６】しかしながら、従来の渦流室式エンジンで
は、副室と主室とを連通する連絡口が小さいので、該連
絡口による絞り損失が発生し、エンジン出力を低減する
原因になる。また、一般に、主室と副室とを連通する連
絡口は、シリンダ中心部或いは外周部の１つの部位のい
ずれかに設けられているので、噴流の到達しなければな
らない距離が長くなり、主室での空気との混合が不十分
になり、ＨＣ、スモークの発生原因になる。そこで、副
室式エンジンにおいて、副室をシリンダ中心に設け、シ
リンダ側の主室と副室とを連通する連絡孔を複数個設
け、副室から連絡孔を通じて主室へ噴出するエネルギー
を低減することなく、連絡孔の全体の通路断面積を大き
くして連絡孔による絞り損失を低減することが考えられ
る。しかしながら、副室をシリンダヘッドのシリンダの
ほぼ中央部に形成すると、吸排気ポートの形成する領域
が小さくなるという問題がある。この点を解決するた
め、副室式エンジンにおいて、ピストンに副室を構成す
ることが考えられる。ピストンに副室を形成した場合に
は、副室からの熱エネルギーの放熱が問題になる。However, in the conventional swirl chamber type engine, since the communication port that connects the sub chamber and the main chamber is small, throttling loss occurs due to the communication port, which causes a reduction in engine output. Further, in general, since the communication port that connects the main chamber and the sub chamber is provided at either one of the center portion of the cylinder or the outer peripheral portion, the distance that the jet flow must reach becomes long, Mixing with air in the room becomes insufficient, causing HC and smoke. Therefore, in a sub-chamber engine, the sub-chamber is provided in the center of the cylinder, and a plurality of communication holes that communicate the main chamber and the sub-chamber on the cylinder side are provided to reduce energy ejected from the sub-chamber to the main chamber through the communication holes. However, it is conceivable to increase the entire passage cross-sectional area of the communication hole to reduce the throttling loss due to the communication hole. However, when the sub chamber is formed in the substantially central portion of the cylinder of the cylinder head, there is a problem that the area formed by the intake and exhaust ports becomes small. In order to solve this point, it is conceivable to construct a sub chamber in the piston in the sub chamber engine. When the sub chamber is formed in the piston, heat radiation from the sub chamber becomes a problem.

【０００７】ところで、前掲実開昭６０−１００５２８
号公報に開示された直接噴射式ディーゼルエンジン用ピ
ストンは、燃焼室頂面部の熱負荷の厳しい部分に耐熱材
を用いて耐久性の確保しようとするものであるが、副室
を遮熱構造に構成したものではない。また、前掲実開昭
６０−１４１４４６号公報に開示されたセラミック組込
型ピストンは、燃焼室をセラミック部材で製造し、該セ
ラミック部材をアルミニウム合金のピストン本体にねじ
結合したものである。更に、前掲特開昭６３−１０９２
６７号公報に開示された内燃機関のピストンは、燃焼室
の外周にセラミックファイバーの断熱層を設けるもので
あり、燃焼室にピストン本体の溶湯が進入するのを防止
し、燃焼室の強度を確保したものであり、燃焼室を耐熱
金属で作製した場合に断熱層は何でも利用できるもので
あり、耐熱金属と断熱層との組合せに特殊性を有してい
るものではない。By the way, the above-mentioned J.S.A.
The direct-injection diesel engine piston disclosed in Japanese Patent Publication No. 3 is intended to ensure durability by using a heat-resistant material in the portion of the combustion chamber top surface where the heat load is severe, but the sub-chamber has a heat shield structure. Not configured. The ceramic-embedded piston disclosed in Japanese Utility Model Laid-Open No. 60-141446 has a combustion chamber made of a ceramic member, and the ceramic member is screwed to a piston body made of an aluminum alloy. Further, the above-mentioned JP-A-63-1092.
The piston of the internal combustion engine disclosed in Japanese Patent Publication No. 67 has a heat insulating layer of ceramic fibers provided on the outer periphery of the combustion chamber, prevents molten metal of the piston body from entering the combustion chamber, and secures the strength of the combustion chamber. Any heat insulating layer can be used when the combustion chamber is made of a heat resistant metal, and the combination of the heat resistant metal and the heat insulating layer does not have peculiarity.

【０００８】この発明の目的は、上記の課題を解決する
ことであり、副室をピストン側に形成してシリンダヘッ
ドをシンプルな構造にし、吸排気ポートを大きく形成し
たり、吸排気ポートをそれぞれ複数個形成することを可
能にし、特に、副室を形成した副室構造体或いはそのピ
ストン頂部を耐熱合金で作製し、アルミニウム合金等の
金属から成るピストン本体に結合するため、両者をそれ
らの熱膨張量をコントロールできる結合部材で安定した
結合力で強固に結合し、副室の遮熱効果をアップして副
室からピストン本体への熱放散を防止し、副室を中央に
配置することで副室からの噴流の到達距離を短くし、連
絡孔の通路面積を増大することで連絡孔による絞り損失
を低減し、主室に存在する新気との混合を促進して燃焼
期間を短縮して性能を向上させることができる副室を持
つピストンの構造を提供することである。An object of the present invention is to solve the above-mentioned problems. A sub chamber is formed on the piston side to make the cylinder head have a simple structure, a large intake / exhaust port is formed, and an intake / exhaust port is provided. It is possible to form a plurality of sub-chambers, and in particular, the sub-chamber structure in which the sub-chamber is formed or the piston top part is made of a heat-resistant alloy and is joined to the piston body made of a metal such as an aluminum alloy. The coupling member that can control the amount of expansion firmly couples with a stable coupling force, improves the heat shield effect of the sub chamber, prevents heat dissipation from the sub chamber to the piston body, and arranges the sub chamber in the center. By shortening the reaching distance of the jet from the sub chamber and increasing the passage area of the communication hole, the throttling loss due to the communication hole is reduced, and the combustion period is shortened by promoting the mixing with the fresh air existing in the main chamber. Sex It is to provide a structure of a piston with a sub chamber which can be improved.

【０００９】[0009]

【課題を解決するための手段】この発明は、上記目的を
達成するため、次のように構成されている。即ち、この
発明は、ピストン本体が金属で作製されており、該ピス
トン本体のピストンヘッドのほぼ中央に形成されたキャ
ビティに副室を形成する副室構造体を配置し、シリンダ
ヘッドに配置された燃料噴射ノズルがピストン上死点近
傍で突入できるノズル挿入孔と該ノズル挿入孔の周方向
に隔置した前記副室と主室とを連通する複数の連絡孔と
が前記副室構造体のピストン頂部側に形成されているピ
ストンの構造において、前記副室構造体が低熱膨張の耐
熱合金で作製されており、前記副室構造体の外壁面と前
記ピストン本体の前記キャビティの壁面とが前記ピスト
ン本体と前記副室構造体との中間の熱膨張係数を有する
結合部材によって結合されていることを特徴とする副室
を持つピストンの構造に関する。The present invention is configured as follows to achieve the above object. That is, according to the present invention, the piston main body is made of metal, and the sub-chamber structure that forms the sub-chamber is arranged in the cavity formed in the substantially central portion of the piston head of the piston main body. A piston of the sub-chamber structure has a nozzle insertion hole through which the fuel injection nozzle can be inserted near the top dead center of the piston, and a plurality of communication holes communicating the main chamber with the sub-chamber, which are spaced apart from each other in the circumferential direction of the nozzle insertion hole. In the structure of the piston formed on the top side, the sub-chamber structure is made of a heat-resistant alloy having a low thermal expansion, and the outer wall surface of the sub-chamber structure and the wall surface of the cavity of the piston body are the piston. The present invention relates to a structure of a piston having a sub chamber, wherein the main body and the sub chamber structure are connected by a connecting member having an intermediate coefficient of thermal expansion.

【００１０】また、この副室を持つピストンの構造にお
いて、前記副室構造体の前記ピストン頂部側は、低熱膨
張で耐熱性に優れたインコロイ９０３又はＳｉ3 Ｎ4 で
構成され、前記副室構造体にメタルフローで接合されて
いるものである。また、前記結合部材は前記副室構造体
から前記ピストン本体に向かって熱膨張係数が大きくな
る熱膨張傾斜部材から成るものである。Further, in the structure of the piston having the sub chamber, the piston top side of the sub chamber structure is made of Incoloy 903 or Si 3 N 4 having low thermal expansion and excellent heat resistance, It is joined to the body by metal flow. Further, the coupling member is composed of a thermal expansion gradient member whose coefficient of thermal expansion increases from the sub chamber structure toward the piston body.

【００１１】又は、この発明は、ピストン本体が金属で
作製されており、該ピストン本体のピストンヘッドのほ
ぼ中央に形成されたキャビティに副室を形成した副室構
造体を配置し、シリンダヘッドに配置された燃料噴射ノ
ズルがピストン上死点近傍で突入できるノズル挿入孔と
該ノズル挿入孔の周方向に隔置した前記副室と主室とを
連通する複数の連絡孔とが前記副室構造体のピストン頂
部に形成されているピストンの構造において、前記ピス
トン頂部側が耐熱合金又は耐熱セラミックスで作製さ
れ、前記副室構造体の周壁体と底壁体とが前記ピストン
頂部と前記ピストン本体との中間の熱膨張係数を有する
耐熱合金で作製され、前記周壁体と前記ピストン本体と
はメタルフローで結合されていることを特徴とする副室
を持つピストンの構造に関する。Alternatively, according to the present invention, the piston body is made of metal, and a sub-chamber structure in which a sub-chamber is formed is arranged in a cavity formed at substantially the center of the piston head of the piston body. The sub-chamber structure has a nozzle insertion hole through which the arranged fuel injection nozzle can project near the top dead center of the piston, the sub-chamber which is spaced in the circumferential direction of the nozzle insertion hole, and a plurality of communication holes which communicate the main chamber. In the structure of the piston formed on the piston top part of the body, the piston top side is made of a heat-resistant alloy or heat-resistant ceramics, the peripheral wall body and the bottom wall body of the sub-chamber structure of the piston top part and the piston body A structure of a piston having a sub-chamber, characterized in that it is made of a heat-resistant alloy having an intermediate coefficient of thermal expansion, and the peripheral wall body and the piston body are connected by a metal flow. On.

【００１２】また、この副室を持つピストンの構造にお
いて、前記周壁体と前記底壁体とを構成する前記副室構
造体はニレジスト、ＡｌＮの多孔質体にＡｌ合金を充填
した複合材、或いはＴｉ−Ｓｉ−Ｃ繊維強化セラミック
スで作製されている。また、前記副室構造体の前記ピス
トン頂部はインコロイ９０３又はＳｉ3 Ｎ4 セラミック
スである。In the structure of the piston having the sub chamber, the sub chamber structure forming the peripheral wall body and the bottom wall body is Niresist, a composite material of AlN porous body filled with Al alloy, or It is made of Ti-Si-C fiber reinforced ceramics. Further, the piston top portion of the sub chamber structure is made of Incoloy 903 or Si 3 N 4 ceramics.

【００１３】また、この副室を持つピストンの構造にお
いて、前記副室構造体は前記ピストン本体に鋳込みによ
って配置されている。更に、前記副室構造体の外面と前
記ピストン本体の前記キャビティ壁面との間にはセラミ
ックファイバー又はＰＳＺ溶射層から成る遮熱材が介在
されているものである。Further, in the structure of the piston having the sub chamber, the sub chamber structure is arranged in the piston body by casting. Further, a heat shield made of ceramic fiber or PSZ sprayed layer is interposed between the outer surface of the sub chamber structure and the cavity wall surface of the piston body.

【００１４】[0014]

【作用】この発明による副室を持つピストンの構造は、
上記のように構成され、次のように作用する。即ち、こ
の副室を持つピストンの構造は、ピストン本体をアルミ
ニウム合金の金属で作製し、前記ピストン本体に配置さ
れ且つノズル挿入孔と複数の連絡孔を備えた副室を形成
する副室構造体を低熱膨張の耐熱合金で作製し、前記副
室構造体の外壁面と前記ピストン本体の前記キャビティ
の壁面とをそれらの中間の熱膨張係数を有する結合部材
によって結合したので、前記ピストン本体と前記副室構
造体との熱膨張量を前記結合部材でコントロールでき、
強固に且つ安定した結合力を確保でき、耐久性に富んだ
ピストンを提供できる。The structure of the piston having the sub chamber according to the present invention is
It is configured as described above and operates as follows. That is, the structure of a piston having this sub-chamber is a sub-chamber structure in which the piston body is made of an aluminum alloy metal and is formed in the piston body to form a sub-chamber having a nozzle insertion hole and a plurality of communication holes. Is made of a heat-resistant alloy having a low thermal expansion, and the outer wall surface of the sub-chamber structure and the wall surface of the cavity of the piston body are coupled by a coupling member having a thermal expansion coefficient between them, so that the piston body and the The amount of thermal expansion with the sub-chamber structure can be controlled by the connecting member,
A strong and stable coupling force can be secured, and a highly durable piston can be provided.

【００１５】また、前記副室構造体を金属材料で作製さ
れるピストン本体に鋳込みで固定する場合に、鋳込み時
に前記副室構造体の外面に遮熱材を付与して鋳込むこと
によって、前記副室構造体の外面と前記ピストン本体の
前記キャビティ壁面との間には遮熱層を容易に形成で
き、前記副室の遮熱効果は大幅にアップされる。前記副
室内は空気流動が大であり、熱伝達率も高く、ガス温度
も高温であるため放熱量が大きくなるので、前記副室を
遮熱構造にすることにより、放熱を防止することがで
き、熱効率を大幅に向上させることができる。この場合
には、前記遮熱材は、鋳込み金属の溶湯では焼失せず、
或いは剥離しない材料を選定しておくことが好ましい。When the sub-chamber structure is fixed to the piston body made of a metal material by casting, by applying a heat shield material to the outer surface of the sub-chamber structure during casting, A heat shield layer can be easily formed between the outer surface of the sub chamber structure and the cavity wall surface of the piston body, and the heat shield effect of the sub chamber is significantly improved. Since the air flow in the sub chamber is large, the heat transfer coefficient is high, and the gas temperature is high, the amount of heat radiation is large. Therefore, by making the sub chamber a heat shield structure, heat radiation can be prevented. , The thermal efficiency can be greatly improved. In this case, the heat shield is not burned out by the molten metal of the cast metal,
Alternatively, it is preferable to select a material that does not peel off.

【００１６】また、前記副室構造体を構成する耐熱合金
としては、インコロイ９０３等の低熱膨張係数で耐熱性
に富んだ材料が好ましい。前記結合部材を構成する熱膨
張傾斜部材は、前記副室構造体側から前記ピストン本体
側へ向かって熱膨張係数が大きくなり、最外周部では前
記ピストン本体の熱膨張係数に近い材料に構成すること
が好ましい。また、前記熱膨張傾斜部材は、例えば、遠
心鋳造によって回転させながら、同心円上に熱膨張係数
の異なる材料を少しずつ重ねて成形し、該成形体を焼結
することによって作製できる。前記結合部材は、前記ピ
ストン本体に接する側には、例えば、アルミニウム合金
の熱膨張係数に近い熱膨張係数を有するニレジストが位
置するように作製する。As the heat-resistant alloy forming the sub-chamber structure, a material having a low coefficient of thermal expansion and a high heat resistance, such as Incoloy 903, is preferable. The thermal expansion gradient member constituting the coupling member has a coefficient of thermal expansion that increases from the side of the sub chamber structure toward the side of the piston body, and is made of a material close to the coefficient of thermal expansion of the piston body at the outermost peripheral portion. Is preferred. The thermal expansion gradient member can be manufactured by, for example, rotating by centrifugal casting, molding concentrically circularly different materials having different thermal expansion coefficients little by little, and sintering the molded body. The coupling member is manufactured so that, for example, a niresist having a thermal expansion coefficient close to that of an aluminum alloy is located on the side in contact with the piston body.

【００１７】また、この副室を持つピストンの構造は、
前記副室がピストンの中央に位置するため、連絡孔から
の噴流の到達距離が短く、燃焼時間が短くなって性能が
向上する。また、前記副室からの噴流の到達距離が短く
て済むため、前記連絡孔の通路面積を大きく形成でき、
絞り損失を低減でき効率を向上できる。また、前記連絡
孔の傾斜方向を外向きに傾斜させると、ピストンの周辺
への前記副室からの噴流の到達距離が更に短くなり、シ
リンダ周辺の新気との混合を促進する。The structure of the piston having the sub chamber is
Since the sub chamber is located at the center of the piston, the distance that the jet flow reaches from the communication hole is short, the combustion time is short, and the performance is improved. Also, since the jet flow distance from the sub chamber can be short, the passage area of the communication hole can be formed large,
The diaphragm loss can be reduced and the efficiency can be improved. Further, when the inclination direction of the communication hole is inclined outward, the reach distance of the jet flow from the sub chamber to the periphery of the piston is further shortened, and mixing with fresh air around the cylinder is promoted.

【００１８】[0018]

【実施例】以下、図面を参照して、この発明による副室
を持つピストンの構造の実施例を説明する。図１はこの
発明による副室を持つピストンの構造の一実施例を示す
断面図、及び図２は図１の副室を持つピストンの構造に
おけるピストンの上面図である。Embodiments of the structure of a piston having a sub chamber according to the present invention will be described below with reference to the drawings. 1 is a sectional view showing an embodiment of the structure of a piston having a sub chamber according to the present invention, and FIG. 2 is a top view of the piston in the structure of the piston having a sub chamber of FIG.

【００１９】この副室を持つピストンの構造を組み込ん
だ副室式エンジンは、アルミニウム合金等の金属材料か
ら成るシリンダ１４を構成するシリンダブロック２６、
該シリンダブロック２６にガスケット２３を介在して固
定されたアルミニウム合金等の金属材料から成るシリン
ダヘッド２５を有する。シリンダブロック２６は、エン
ジンの気筒数に対応する孔部を形成し、該孔部にシリン
ダ１４を形成するシリンダライナを嵌合して構成しても
よい。シリンダヘッド２５には、エンジンの気筒数に対
応即ちシリンダ１４に対応する吸排気ポート（図示せ
ず）が形成され、該吸排気ポートには吸排気弁（図示せ
ず）が配置されている。シリンダブロック２６に形成さ
れたシリンダ１４には、ピストン３が往復運動するよう
に組み込まれている。主室１は、シリンダヘッド下面２
４とピストン頂面１８との間のシリンダ１４側に形成さ
れている。また、ピストン３には、副室２が形成されて
いる。The sub-chamber engine incorporating the structure of the piston having the sub-chamber has a cylinder block 26 which constitutes the cylinder 14 made of a metal material such as an aluminum alloy.
A cylinder head 25 made of a metal material such as an aluminum alloy is fixed to the cylinder block 26 with a gasket 23 interposed therebetween. The cylinder block 26 may be formed by forming holes corresponding to the number of cylinders of the engine, and fitting a cylinder liner forming the cylinder 14 into the holes. The cylinder head 25 is formed with intake / exhaust ports (not shown) corresponding to the number of cylinders of the engine, that is, corresponding to the cylinders 14, and intake / exhaust valves (not shown) are arranged in the intake / exhaust ports. In the cylinder 14 formed in the cylinder block 26, the piston 3 is incorporated so as to reciprocate. The main chamber 1 has a cylinder head lower surface 2
4 and the piston top surface 18 on the cylinder 14 side. A sub chamber 2 is formed in the piston 3.

【００２０】この発明は、液体燃料を燃料噴射ノズル１
０から副室２内に噴射して燃焼させるディーゼルエンジ
ンであり、シリンダ１４内を往復運動するピストン３の
構造に特徴を有するものである。ピストン３は、ピスト
ンヘッド部とピストンスカート部を有するピストン本体
４と、副室２を形成した副室構造体８とから構成されて
いる。副室構造体８は、耐熱性に富んだ窒化ケイ素、炭
化ケイ素、或いはセラミックウィスカーと金属との複合
材料、インコネル９０３或いはＮｉ−Ｃｒ系の耐熱合金
によって製作されている。また、ピストン本体４は、ア
ルミニウム合金等の金属材料で作製されている。副室構
造体４には、シリンダ１４のほぼ中央に位置する副室
２、該副室２の中央に位置するノズル挿入孔７及びノズ
ル挿入孔７の回りの周方向に隔置した複数個（図２では
６個）の連絡孔９が形成されている。連絡孔９は、ノズ
ル挿入孔７の回りの周方向にシリンダ周辺側に向かって
傾斜方向に形成されている。In the present invention, liquid fuel is used for the fuel injection nozzle 1.
It is a diesel engine that injects from 0 to the inside of the sub chamber 2 and burns it, and is characterized by the structure of the piston 3 that reciprocates in the cylinder 14. The piston 3 includes a piston body 4 having a piston head portion and a piston skirt portion, and a sub chamber structure 8 forming the sub chamber 2. The sub-chamber structure 8 is made of heat-resistant silicon nitride, silicon carbide, a composite material of ceramic whiskers and a metal, Inconel 903, or a Ni—Cr heat-resistant alloy. The piston body 4 is made of a metal material such as an aluminum alloy. The sub-chamber structure 4 includes a sub-chamber 2 located substantially at the center of the cylinder 14, a nozzle insertion hole 7 located at the center of the sub-chamber 2, and a plurality of circumferentially spaced nozzles around the nozzle insertion hole 7 ( Two communication holes 9 are formed in FIG. The communication hole 9 is formed in an inclined direction in the circumferential direction around the nozzle insertion hole 7 toward the cylinder peripheral side.

【００２１】また、シリンダヘッド５には、シリンダ軸
の中央部に配置された多噴孔１１を備えた燃料噴射ノズ
ル１０が固定され、燃料噴射ノズル１０の噴孔部２５は
シリンダヘッド下面２４から突出している。燃料噴射ノ
ズル１０は、ピストン３の上死点近傍でその噴孔部１２
がノズル挿入孔７を貫通して副室２内へ突入でき、多噴
孔１１から副室２内に燃料を噴射できるものである。な
お、図示していないが、シリンダヘッド２５には始動補
助のためのグロープラグを配置すると共に、副室構造体
４にプラグ挿入孔を形成し、上死点近傍でグロープラグ
が副室２内に突入するように構成することができる。A fuel injection nozzle 10 having multiple injection holes 11 arranged in the center of the cylinder shaft is fixed to the cylinder head 5, and the injection hole portion 25 of the fuel injection nozzle 10 extends from the cylinder head lower surface 24. It is protruding. The fuel injection nozzle 10 has its injection hole portion 12 near the top dead center of the piston 3.
Can penetrate into the sub chamber 2 through the nozzle insertion hole 7 and can inject fuel into the sub chamber 2 from the multiple injection holes 11. Although not shown, a glow plug for assisting starting is arranged in the cylinder head 25, and a plug insertion hole is formed in the sub chamber structure 4 so that the glow plug is located inside the sub chamber 2 near the top dead center. Can be configured to plunge into.

【００２２】この副室を持つピストンの構造は、ピスト
ン本体４のピストンヘッド２５のほぼ中央に形成された
キャビティ１３に副室２を設け、シリンダヘッド２６に
配置された燃料噴射ノズル１０がピストン上死点近傍で
突入できるノズル挿入孔７と該ノズル挿入孔７の周方向
に隔置した副室２と主室１とを連通する複数の連絡孔９
とがピストン頂部５に形成されている。この副室を持つ
ピストンの構造は、特に、副室２を形成する副室構造体
８が低熱膨張の耐熱合金で作製されており、副室構造体
８の外壁面１６とピストン本体４のキャビティ壁面１７
とがピストン本体４と副室構造体８との中間の熱膨張係
数を有する結合部材１９，２０によって結合されている
ことを特徴とするものである。結合部材１９，２０は、
図では、２個の部材として示したが、それに限らず、副
室構造体８からピストン本体４に向かって熱膨張係数が
大きくなるような熱膨張傾斜部材として作製することが
できる。このような熱膨張傾斜部材は、例えば、遠心鋳
造によって回転させながら、同心円上に熱膨張係数の異
なる材料を少しずつ重ねて積層成形し、該積層成形体を
焼結することによって作製でき、結合部材の熱膨張係数
に対する自由度が大きくなる。In the structure of the piston having the sub chamber, the sub chamber 2 is provided in the cavity 13 formed substantially in the center of the piston head 25 of the piston body 4, and the fuel injection nozzle 10 arranged in the cylinder head 26 is mounted on the piston. A nozzle insertion hole 7 that can be inserted near the dead point, and a plurality of communication holes 9 that connect the auxiliary chamber 2 and the main chamber 1 that are separated from each other in the circumferential direction of the nozzle insertion hole 7.
Are formed on the piston top 5. In the structure of the piston having the sub chamber, in particular, the sub chamber structure 8 forming the sub chamber 2 is made of a heat-resistant alloy having low thermal expansion, and the outer wall surface 16 of the sub chamber structure 8 and the cavity of the piston body 4 are Wall 17
Are coupled by the coupling members 19 and 20 having an intermediate coefficient of thermal expansion between the piston body 4 and the sub chamber structure 8. The connecting members 19 and 20 are
Although it is shown as two members in the drawing, the present invention is not limited to this, and it can be manufactured as a thermal expansion gradient member whose thermal expansion coefficient increases from the sub chamber structure 8 toward the piston body 4. Such a thermal expansion gradient member can be produced, for example, by rotating by centrifugal casting while laminating materials having different thermal expansion coefficients on concentric circles little by little, and laminating and molding the laminated body. The degree of freedom with respect to the coefficient of thermal expansion of the member is increased.

【００２３】この副室を持つピストンの構造において、
副室構造体８におけるピストン頂部５は低熱膨張で耐熱
性のインコロイ９０３で構成され、ピストン頂部５は副
室構造体８にメタルフローで接合されている。結合部材
１９，２０は、副室構造体８からピストン本体６に向か
って熱膨張係数が大きくなる熱膨張傾斜部材から構成さ
れている。そして、ピストン本体４に隣接する結合部材
２０は、ピストン本体４がアルミニウム合金の場合に
は、アルミニウム合金の熱膨張係数に近い熱膨張係数を
有するニレジストから構成することが好ましい。また、
耐熱金属から構成された副室構造体８と結合部材１９と
は、例えば、ビーム溶接で接合することができる。In the structure of the piston having this sub chamber,
The piston top portion 5 of the sub chamber structure 8 is made of Incoloy 903 having low thermal expansion and heat resistance, and the piston top portion 5 is joined to the sub chamber structure 8 by metal flow. The coupling members 19 and 20 are composed of thermal expansion gradient members whose thermal expansion coefficient increases from the sub chamber structure 8 toward the piston body 6. When the piston body 4 is an aluminum alloy, the coupling member 20 adjacent to the piston body 4 is preferably made of Niresist having a thermal expansion coefficient close to that of the aluminum alloy. Also,
The sub-chamber structure 8 made of a refractory metal and the joining member 19 can be joined by beam welding, for example.

【００２４】特に、この副室を持つピストンの構造にお
いて、副室構造体８の外面とピストン本体４のキャビテ
ィ１３の壁面との間には、セラミックファイバー又は部
分安定化ジルコニア（ＰＳＺ）溶射層から成る遮熱材２
１が介在されている。遮熱材２１を副室構造体８とピス
トン本体４との間に介在させるには、副室構造体８の外
面に遮熱材２１を配置してアルミニウム合金でピストン
本体４を鋳込むことによって配置することができる。即
ち、副室構造体８の外面にセラミックスファイバーを付
着させ、その状態でピストン本体４の鋳込みによって遮
熱材２１を両者間に配置することができる。また、副室
構造体８の外面に遮熱材２１を構成する部分安定化ジル
コニアを予め溶射して両者間に配置することもできる。Particularly, in the structure of the piston having the sub chamber, a ceramic fiber or a partially stabilized zirconia (PSZ) sprayed layer is provided between the outer surface of the sub chamber structure 8 and the wall surface of the cavity 13 of the piston body 4. Heat shield material 2
1 is interposed. To interpose the heat shield 21 between the sub-chamber structure 8 and the piston body 4, the heat shield 21 is arranged on the outer surface of the sub-chamber structure 8 and the piston body 4 is cast with an aluminum alloy. Can be placed. That is, the ceramic fiber is attached to the outer surface of the sub chamber structure 8, and the heat shield 21 can be disposed between the two by casting the piston body 4 in that state. It is also possible to spray the partially stabilized zirconia forming the heat shield 21 in advance on the outer surface of the sub chamber structure 8 and arrange it between the two.

【００２５】更に、この副室を持つピストンの構造で
は、連絡孔９がノズル挿入孔７の回りに多数形成され、
連絡孔９の通路面積は全周に分散して全体で大きく形成
され、連絡孔９から噴出した火炎と混合気とは主室１内
の空気と十分に混合することができる。即ち、主室１と
副室２とを連通する連絡孔９は、通路面積が合計で大面
積に構成することができ、絞り損失を低減でき出力の低
減はない。また、副室２がシリンダ中心軸線上に同心に
配置され、連絡孔９が副室２の外周側面に形成されてい
るので、副室２から噴出した噴流が、連絡孔９の通路面
積が大きくなって噴出エネルギーが小さくなり、到達距
離が短くなったとしても、該噴流は主室１に存在する空
気と十分に短期に混合することができ、主室１での燃焼
期間を短縮してＨＣ、スモークの発生を抑制できる。Further, in the structure of the piston having the sub chamber, a large number of communication holes 9 are formed around the nozzle insertion hole 7,
The passage area of the communication hole 9 is dispersed over the entire circumference and is formed large as a whole, so that the flame and the air-fuel mixture ejected from the communication hole 9 can be sufficiently mixed with the air in the main chamber 1. That is, the communication hole 9 that connects the main chamber 1 and the sub chamber 2 can be configured to have a large passage area in total, and the throttle loss can be reduced and the output cannot be reduced. Further, since the sub chamber 2 is arranged concentrically on the cylinder center axis and the communication hole 9 is formed on the outer peripheral side surface of the sub chamber 2, the jet flow ejected from the sub chamber 2 has a large passage area of the communication hole 9. Even if the jetting energy becomes small and the reaching distance becomes short, the jet flow can be mixed with the air existing in the main chamber 1 in a sufficiently short period, and the combustion period in the main chamber 1 can be shortened. , Smoke can be suppressed.

【００２６】次に、図３及び図４を参照して、この発明
による副室を持つピストンの構造の別の実施例を説明す
る。図３はこの発明による副室を持つピストンの構造の
別の実施例を示す断面図、及び図４は図３の副室を持つ
ピストンの構造におけるピストンの上面図である。この
実施例は、上記実施例と比較すると、ピストンヘッドの
構造が相違する以外は、同一の構成及び同一の機能を有
するので、同一の部品には同一の符号を付し、重複する
説明は省略する。図３及び図４に示す実施例において、
副室構造体８におけるピストン頂部５は低熱膨張で耐熱
性のＳｉ3 Ｎ4セラミックスで構成され、ピスピストン
本体６がアルミニウム合金の場合には、アルミニウム合
金の熱膨張係数に近い熱膨張係数を有するニレジストか
ら構成することが好ましい。耐熱金属から構成された副
室構造体８と結合部材２０とは、例えば、ビーム溶接で
接合することができる。ピストン頂部５をＳｉ3 Ｎ4 セ
ラミックスで作製した場合には、軽重量に構成でき、慣
性力を低減でき、従って、結合部への慣性力による悪影
響を低減できる。また、Ｓｉ3 Ｎ4 は熱膨張係数が小さ
いので、前記副室の熱変形が小さく、熱応力による悪影
響を低減でき、耐久性を向上できる。Next, another embodiment of the structure of the piston having the auxiliary chamber according to the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a sectional view showing another embodiment of the structure of the piston having the sub chamber according to the present invention, and FIG. 4 is a top view of the piston in the structure of the piston having the sub chamber of FIG. Compared with the above-mentioned embodiment, this embodiment has the same configuration and the same function except that the structure of the piston head is different. Therefore, the same parts are designated by the same reference numerals, and the duplicate description will be omitted. To do. In the embodiment shown in FIGS. 3 and 4,
The piston top 5 in the sub chamber structure 8 is made of heat-resistant Si 3 N 4 ceramics having low thermal expansion, and when the piston piston body 6 is an aluminum alloy, it has a thermal expansion coefficient close to that of the aluminum alloy. It is preferable to be composed of The sub-chamber structure 8 made of a refractory metal and the joining member 20 can be joined by beam welding, for example. When the piston top portion 5 is made of Si 3 N 4 ceramics, it can be constructed in a light weight and the inertial force can be reduced. Therefore, the adverse effect of the inertial force on the joint portion can be reduced. Further, since Si 3 N 4 has a small coefficient of thermal expansion, thermal deformation of the sub chamber is small, adverse effects due to thermal stress can be reduced, and durability can be improved.

【００２７】次に、図５及び図６を参照して、この発明
による副室を持つピストンの構造の更に別の実施例を説
明する。図５はこの発明による副室を持つピストンの構
造の更に別の実施例を示す断面図、及び図６は図５の副
室を持つピストンの構造におけるピストンの上面図であ
る。この実施例は、上記実施例と比較すると、ピストン
ヘッドの構造が相違する以外は、同一の構成及び同一の
機能を有するので、同一の部品には同一の符号を付し、
重複する説明は省略する。この実施例の副室を持つピス
トンの構造は、ピストン頂部５が耐熱合金又は耐熱セラ
ミックスで作製され、副室構造体８の周壁体２２と底壁
体２３とがピストン頂部５とピストン本体４との中間の
熱膨張係数を有する耐熱合金で作製され、周壁体２２と
ピストン本体４とはメタルフローで結合されているもの
である。周壁体２２と底壁体２３とを構成する副室構造
体８は、ピストン本体４のアルミニウム合金の熱膨張係
数に近い熱膨張係数を有するニレジストで作製されてお
り、副室構造体８のピストン頂部５は耐熱性で低熱膨張
係数のインコロイ９０３又はＳｉ3 Ｎ4 セラミックスで
作製されている。Next, another embodiment of the structure of the piston having the sub chamber according to the present invention will be described with reference to FIGS. 5 and 6. 5 is a sectional view showing still another embodiment of the structure of the piston having the sub chamber according to the present invention, and FIG. 6 is a top view of the piston in the structure of the piston having the sub chamber of FIG. Compared with the above-mentioned embodiment, this embodiment has the same configuration and the same function except that the structure of the piston head is different. Therefore, the same reference numerals are given to the same parts,
A duplicate description will be omitted. In the structure of the piston having the sub chamber of this embodiment, the piston top portion 5 is made of a heat-resistant alloy or heat-resistant ceramic, and the peripheral wall body 22 and the bottom wall body 23 of the sub chamber structure 8 are the piston top portion 5, the piston body 4, and It is made of a heat-resistant alloy having an intermediate coefficient of thermal expansion, and the peripheral wall 22 and the piston body 4 are joined together by metal flow. The sub-chamber structure 8 forming the peripheral wall body 22 and the bottom wall body 23 is made of Niresist having a thermal expansion coefficient close to that of the aluminum alloy of the piston body 4, and the piston of the sub-chamber structure 8 is formed. The top portion 5 is made of Incoloy 903 or Si 3 N 4 ceramics having heat resistance and a low coefficient of thermal expansion.

【００２８】次に、図７及び図８を参照して、この発明
による副室を持つピストンの構造の更に別の実施例を説
明する。図７はこの発明による副室を持つピストンの構
造の更に別の実施例を示す断面図、及び図８は図７の副
室を持つピストンの構造におけるピストンの上面図であ
る。この実施例は、上記実施例と比較すると、ピストン
ヘッドの構造が相違する以外は、同一の構成及び同一の
機能を有するので、同一の部品には同一の符号を付し、
重複する説明は省略する。この実施例の副室を持つピス
トンの構造は、副室構造体８はピストン頂部５、周壁体
２２及び底壁体２３が一体構造に構成されており、Ａｌ
Ｎの多孔質体にＡｌ合金をしみ込ませた即ち充填した複
合材で作製されている。この実施例では、ピストン頂部
５の温度は４５０℃以下になるように構成されている。
遮熱材２１は、副室構造体８の外面にＰＳＺ等を溶射
し、ピストン本体４に鋳込むことによって副室構造体８
とピストン本体４との間に配置される。Another embodiment of the structure of the piston having the auxiliary chamber according to the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a sectional view showing still another embodiment of the structure of the piston having the sub chamber according to the present invention, and FIG. 8 is a top view of the piston in the structure of the piston having the sub chamber of FIG. Compared with the above-mentioned embodiment, this embodiment has the same configuration and the same function except that the structure of the piston head is different. Therefore, the same reference numerals are given to the same parts,
A duplicate description will be omitted. In the structure of the piston having the sub chamber of this embodiment, the sub chamber structure 8 has a piston top portion 5, a peripheral wall body 22 and a bottom wall body 23 which are integrally formed.
It is made of a composite material in which a porous body of N is impregnated with or filled with an Al alloy. In this embodiment, the temperature of the piston top portion 5 is configured to be 450 ° C. or lower.
The heat shield 21 is sprayed with PSZ or the like on the outer surface of the sub-chamber structure 8 and cast into the piston body 4 to form the sub-chamber structure 8.
Is disposed between the piston body 4 and the piston body 4.

【００２９】次に、図９及び図１０を参照して、この発
明による副室を持つピストンの構造の更に別の実施例を
説明する。図９はこの発明による副室を持つピストンの
構造の更に別の実施例を示す断面図、及び図１０は図９
の副室を持つピストンの構造におけるピストンの上面図
である。この実施例は、上記実施例と比較すると、ピス
トンヘッドの構造が相違する以外は、同一の構成及び同
一の機能を有するので、同一の部品には同一の符号を付
し、重複する説明は省略する。この実施例の副室を持つ
ピストンの構造は、周壁体２２と底壁体２３とを構成す
る副室構造体８は、低熱膨張係数で高強度の高遮熱度の
Ｔｉ−Ｓｉ−Ｃ繊維強化セラミックス〔例えば、チラノ
ウィスカー強化コーディエライト（２ＭｇＯ・２Ａｌ2
Ｏ3 ・５ＳｉＯ2 ）〕で作製されている。Next, another embodiment of the structure of the piston having the sub chamber according to the present invention will be described with reference to FIGS. 9 is a sectional view showing still another embodiment of the structure of the piston having the sub chamber according to the present invention, and FIG.
It is a top view of the piston in the structure of the piston which has the sub chamber of FIG. Compared with the above-mentioned embodiment, this embodiment has the same configuration and the same function except that the structure of the piston head is different. Therefore, the same parts are designated by the same reference numerals, and the duplicate description will be omitted. To do. In the structure of the piston having the sub-chamber of this embodiment, the sub-chamber structure 8 constituting the peripheral wall body 22 and the bottom wall body 23 is reinforced with Ti-Si-C fiber having a low thermal expansion coefficient and high strength and high heat shield. Ceramics [For example, Tyranno whisker reinforced cordierite (2MgO.2Al 2
O 3 .5SiO 2 )].

【００３０】[0030]

【発明の効果】この発明による副室を持つピストンの構
造は、上記のように構成されており、次のような効果を
有する。この副室を持つピストンの構造は、ピストン本
体をアルミニウム合金等の金属で作製し、前記ピストン
本体に配置され且つノズル挿入孔と複数の連絡孔を備え
た副室を形成する副室構造体を低熱膨張の耐熱合金、耐
熱セラミックスで作製し、前記副室構造体の外壁面と前
記ピストン本体の前記キャビティの壁面とをそれらの中
間の熱膨張係数を有する結合部材を配置した状態で鋳込
みによって結合したので、前記ピストン本体と前記副室
構造体との熱膨張量を前記結合部材でコントロールで
き、強固に且つ安定した結合力を確保でき、耐久性に富
んだピストンを提供できる。特に、前記ピストン本体を
アルミニウム合金で作製した場合には、前記結合部材と
して前記ピストン本体に隣接した側の部分を、アルミニ
ウム合金の熱膨張係数に近い熱膨張係数を有するニレジ
ストで作製することによって熱負荷を受けても強固に安
定した結合力を維持しておくことができる。The structure of the piston having the sub chamber according to the present invention is constructed as described above and has the following effects. The structure of a piston having this sub-chamber is a sub-chamber structure in which the piston main body is made of a metal such as aluminum alloy and which is arranged in the piston main body and forms a sub-chamber with a nozzle insertion hole and a plurality of communication holes. It is made of a heat-resistant alloy or heat-resistant ceramics having a low thermal expansion, and the outer wall surface of the sub-chamber structure and the wall surface of the cavity of the piston body are joined by casting with a joining member having a coefficient of thermal expansion intermediate between them being arranged. Therefore, the amount of thermal expansion between the piston body and the sub-chamber structure can be controlled by the coupling member, a strong and stable coupling force can be secured, and a highly durable piston can be provided. In particular, when the piston body is made of an aluminum alloy, the portion of the side adjacent to the piston body as the connecting member is made of Niresist having a thermal expansion coefficient close to that of an aluminum alloy. It is possible to maintain a strong and stable binding force even under load.

【００３１】また、前記副室構造体における前記ピスト
ン頂部は、前記主室と前記副室とを連通する複数の前記
連絡孔が形成され、高温ガスに晒されて高温領域になる
ので、耐熱性に富み且つ低熱膨張係数の耐熱合金、例え
ば、インコロイ９０３で作製することが好ましい。或い
は、前記ピストン頂部は耐熱性に富み且つ低熱膨張係数
のＳｉ3 Ｎ4 セラミックスで作製することもできる。Further, the piston top portion of the sub chamber structure is formed with a plurality of the communication holes for communicating the main chamber and the sub chamber, and is exposed to high temperature gas to become a high temperature region. It is preferable to manufacture it with a heat-resistant alloy having a high thermal expansion coefficient and a low coefficient of thermal expansion, for example, Incoloy 903. Alternatively, the piston top may be made of Si 3 N 4 ceramics, which has high heat resistance and a low coefficient of thermal expansion.

【００３２】前記副室構造体を前記ピストン本体に鋳込
むことにより、前記副室構造体と前記ピストン本体との
境界面を互いに強固に当接させることができ、両者の境
界面を密接に接触した状態になり、両者間の境界面のシ
ールを良好にする。従って、両者間にシール部材を配置
する必要がなくなり、構造を簡単にできる。しかも、前
記副室構造体と前記ピストン本体との間に遮熱材を配置
することによって、前記副室の遮熱効果を大幅にアップ
でき、前記副室からの熱エネルギーの放熱を抑制でき、
燃費を向上できる。或いは、前記副室構造体における前
記ピストン頂部を周壁体から別体に構成し、前記周壁体
と前記ピストン頂部とを金属の塑性変形即ちメタルフロ
ーで固定することも可能であり、或いはビーム溶接で固
定することもできる。By casting the sub-chamber structure into the piston body, the boundary surfaces of the sub-chamber structure and the piston body can be firmly brought into contact with each other, and the boundary surfaces of both can be in close contact with each other. Then, the interface between them is well sealed. Therefore, it is not necessary to dispose a seal member between the two, and the structure can be simplified. Moreover, by disposing a heat shield between the sub-chamber structure and the piston body, the heat shield effect of the sub-chamber can be significantly increased, and heat radiation from the sub-chamber can be suppressed.
Fuel efficiency can be improved. Alternatively, it is also possible to configure the piston top portion of the sub chamber structure separately from the peripheral wall body and fix the peripheral wall body and the piston top portion by plastic deformation of metal, that is, metal flow, or by beam welding. It can also be fixed.

【００３３】また、前記副室構造体は前記ピストン本体
に堅固に固定され、ピストンのほぼ中央に前記副室を形
成した副室式燃焼室を構成でき、燃料リッチで燃焼させ
てＮＯX の発生を低減できる。特に、前記副室構造体に
形成した前記副室を遮熱構造に構成してピストンの熱負
荷を低減でき、前記副室から外部への熱放散を防止で
き、熱効率を向上させることができる。また、ピストン
ヘッドの中央部には、ピストン上死点近傍で燃料噴射ノ
ズルが突入できるノズル挿入孔を形成し、前記主室と前
記副室とを連通する複数個の前記連絡孔を前記ノズル挿
入孔の周囲にシリンダ軸に対して斜めに且つ周囲方向に
隔置して形成したので、前記副室が前記ピストンの中央
に位置し、前記連絡孔からの噴流の到達距離が短く、燃
焼時間が短くなってシリンダ周辺の新気との混合を促進
して性能が向上する。また、前記副室からの噴流の到達
距離が短くて済むため、前記連絡孔の通路面積を合計で
全体として大きく形成でき、絞り損失を低減でき効率を
向上できる。従って、この副室を持つピストンの構造
は、前記副室での燃焼状態を燃料リッチで燃焼させ且つ
直接噴射式燃焼室と同等の燃焼スピードを確保でき、Ｎ
ＯX の発生を抑制でき、前記主室での混合が促進され、
燃焼スピードを速くして燃焼期間を短縮でき、ＮＯX 、
ＨＣ、スモークの発生を抑制できる燃焼を行わせること
ができる。Further, the auxiliary chamber structure is rigidly secured to the piston body, can configure the sub-chamber type combustion chamber which is formed the auxiliary chamber substantially in the center of the piston, generating of the NO X is burned in the fuel-rich Can be reduced. In particular, the sub-chamber formed in the sub-chamber structure can be configured as a heat shield structure to reduce the heat load on the piston, prevent heat dissipation from the sub-chamber to the outside, and improve thermal efficiency. In addition, a nozzle insertion hole through which a fuel injection nozzle can project near the piston top dead center is formed in the center of the piston head, and a plurality of the communication holes that connect the main chamber and the sub chamber are inserted into the nozzle insertion hole. Since it was formed obliquely around the hole with respect to the cylinder axis and spaced in the circumferential direction, the sub chamber is located at the center of the piston, the arrival distance of the jet flow from the communication hole is short, and the combustion time is It shortens and promotes mixing with the fresh air around the cylinder, improving performance. Further, since the jet flow from the sub-chamber needs only to reach a short distance, the passage area of the communication hole can be formed to be large in total, the throttle loss can be reduced, and the efficiency can be improved. Therefore, the structure of the piston having this sub-chamber makes it possible to burn the combustion state in the sub-chamber in a fuel rich manner and to secure a combustion speed equivalent to that of the direct injection type combustion chamber.
Generation of O X can be suppressed, mixing in the main chamber is promoted,
The combustion speed can be increased to shorten the combustion period, NO X ,
Combustion that can suppress the generation of HC and smoke can be performed.

【図面の簡単な説明】[Brief description of drawings]

【図１】この発明による副室を持つピストンの構造の一
実施例を示す断面図である。FIG. 1 is a sectional view showing an embodiment of the structure of a piston having a sub chamber according to the present invention.

【図２】図１の副室を持つピストンの上面図である。FIG. 2 is a top view of a piston having the sub chamber of FIG.

【図３】この発明による副室を持つピストンの構造の別
の実施例を示す断面図である。FIG. 3 is a sectional view showing another embodiment of the structure of a piston having a sub chamber according to the present invention.

【図４】図３の副室を持つピストンの上面図である。FIG. 4 is a top view of a piston having the sub chamber of FIG.

【図５】この発明による副室を持つピストンの構造の更
に別の実施例を示す断面図である。FIG. 5 is a sectional view showing still another embodiment of the structure of the piston having the sub chamber according to the present invention.

【図６】図５の副室を持つピストンの上面図である。FIG. 6 is a top view of a piston having the sub chamber of FIG.

【図７】この発明による副室を持つピストンの構造の他
の実施例を示す断面図である。FIG. 7 is a sectional view showing another embodiment of the structure of the piston having the sub chamber according to the present invention.

【図８】図７の副室を持つピストンの上面図である。8 is a top view of a piston having the sub chamber of FIG. 7. FIG.

【図９】この発明による副室を持つピストンの構造の更
に他の実施例を示す断面図である。FIG. 9 is a sectional view showing still another embodiment of the structure of the piston having the sub chamber according to the present invention.

【図１０】図９の副室を持つピストンの上面図である。FIG. 10 is a top view of a piston having the sub chamber of FIG.

【符号の説明】[Explanation of symbols]

１ 主室 ２ 副室 ３ ピストン ４ ピストン本体 ５ ピストン頂部 ６ ピストンヘッド ７ ノズル挿入孔 ８ 副室構造体 ９ 連絡孔 １０ 燃料噴射ノズル １１ 多噴孔 １２ 噴孔部 １３ キャビティ １４ シリンダ １６ 副室構造体の外壁面 １７ キャビティ壁面 １８ ピストン頂面 １９，２０ 結合部材 ２１ 遮熱材 ２２ 周壁体 ２３ 底壁体 ２４ シリンダヘッド下面 ２５ シリンダヘッド 1 Main Chamber 2 Sub Chamber 3 Piston 4 Piston Body 5 Piston Top 6 Piston Head 7 Nozzle Insertion Hole 8 Sub Chamber Structure 9 Communication Hole 10 Fuel Injection Nozzle 11 Multiple Injection Hole 12 Injection Hole 13 Cavity 14 Cylinder 16 Sub Chamber Structure Outer wall surface 17 Cavity wall surface 18 Piston top surface 19,20 Coupling member 21 Heat shield 22 Peripheral wall body 23 Bottom wall body 24 Cylinder head lower surface 25 Cylinder head

フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｆ０２Ｂ 19/16 Ａ Ｆ０２Ｆ 3/26 Ａ Continuation of the front page (51) Int.Cl. 6 Identification code Office reference number FI Technical display area F02B 19/16 A F02F 3/26 A

Claims (8)

【特許請求の範囲】[Claims] 【請求項１】 ピストン本体が金属で作製されており、
該ピストン本体のピストンヘッドのほぼ中央に形成され
たキャビティに副室を形成する副室構造体を配置し、シ
リンダヘッドに配置された燃料噴射ノズルがピストン上
死点近傍で突入できるノズル挿入孔と該ノズル挿入孔の
周方向に隔置した前記副室と主室とを連通する複数の連
絡孔とが前記副室構造体のピストン頂部側に形成されて
いるピストンの構造において、前記副室構造体が低熱膨
張の耐熱合金で作製されており、前記副室構造体の外壁
面と前記ピストン本体の前記キャビティの壁面とが前記
ピストン本体と前記副室構造体との中間の熱膨張係数を
有する結合部材によって結合されていることを特徴とす
る副室を持つピストンの構造。1. The piston body is made of metal,
A sub-chamber structure that forms a sub-chamber is arranged in a cavity formed substantially at the center of the piston head of the piston body, and a nozzle insertion hole through which a fuel injection nozzle arranged in the cylinder head can enter near the piston top dead center. In the structure of the piston, the auxiliary chamber and a plurality of communication holes communicating with the main chamber, which are separated from each other in the circumferential direction of the nozzle insertion hole, are formed on the piston top side of the auxiliary chamber structure. The body is made of a heat-resistant alloy having low thermal expansion, and the outer wall surface of the sub chamber structure and the wall surface of the cavity of the piston body have a coefficient of thermal expansion intermediate between the piston body and the sub chamber structure. A structure of a piston having a sub chamber characterized by being connected by a connecting member. 【請求項２】 前記副室構造体の前記ピストン頂部側
は、低熱膨張で耐熱性に優れたインコロイ９０３又はＳ
ｉ3 Ｎ4 で構成され、前記副室構造体にメタルフローで
接合されていることを特徴とする請求項１に記載の副室
を持つピストンの構造。2. The Incoloy 903 or S having low thermal expansion and excellent heat resistance is provided on the piston top side of the sub chamber structure.
The structure of a piston having a sub chamber according to claim 1, wherein the piston is formed of i 3 N 4 and is joined to the sub chamber structure by metal flow. 【請求項３】 前記結合部材は前記副室構造体から前記
ピストン本体に向かって熱膨張係数が大きくなる熱膨張
傾斜部材から成ることを特徴とする請求項１及び２のい
ずれかに記載の副室を持つピストンの構造。3. The auxiliary member according to claim 1, wherein the connecting member comprises a thermal expansion gradient member having a thermal expansion coefficient increasing from the sub chamber structure toward the piston body. Structure of piston with chamber. 【請求項４】 ピストン本体が金属で作製されており、
該ピストン本体のピストンヘッドのほぼ中央に形成され
たキャビティに副室を形成した副室構造体を配置し、シ
リンダヘッドに配置された燃料噴射ノズルがピストン上
死点近傍で突入できるノズル挿入孔と該ノズル挿入孔の
周方向に隔置した前記副室と主室とを連通する複数の連
絡孔とが前記副室構造体のピストン頂部に形成されてい
るピストンの構造において、前記ピストン頂部側が耐熱
合金又は耐熱セラミックスで作製され、前記副室構造体
の周壁体と底壁体とが前記ピストン頂部と前記ピストン
本体との中間の熱膨張係数を有する耐熱合金で作製さ
れ、前記周壁体と前記ピストン本体とはメタルフローで
結合されていることを特徴とする副室を持つピストンの
構造。4. The piston body is made of metal,
A sub-chamber structure in which a sub-chamber is formed is arranged in a cavity formed substantially in the center of the piston head of the piston body, and a fuel injection nozzle arranged in the cylinder head is provided with a nozzle insertion hole through which the fuel injection nozzle can enter near the piston top dead center. In the structure of a piston in which the sub chamber and a plurality of communication holes communicating with the main chamber, which are spaced apart from each other in the circumferential direction of the nozzle insertion hole, are formed in the piston top of the sub chamber structure, the piston top side is heat-resistant. Made of an alloy or a heat-resistant ceramic, the peripheral wall body and the bottom wall body of the sub-chamber structure are made of a heat-resistant alloy having an intermediate thermal expansion coefficient between the piston top portion and the piston body, the peripheral wall body and the piston The structure of the piston with the sub chamber characterized by being connected to the main body by metal flow. 【請求項５】 前記周壁体と前記底壁体とを構成する前
記副室構造体はニレジスト、ＡｌＮの多孔質体にＡｌ合
金を充填した複合材、或いはＴｉ−Ｓｉ−Ｃ繊維強化セ
ラミックスで作製されていることを特徴とする請求項４
に記載の副室を持つピストンの構造。5. The sub-chamber structure forming the peripheral wall body and the bottom wall body is made of Niresist, a composite material of AlN porous body filled with Al alloy, or Ti—Si—C fiber reinforced ceramics. It is characterized by the above-mentioned.
Structure of piston with sub chamber described in. 【請求項６】 前記副室構造体の前記ピストン頂部はイ
ンコロイ９０３又はＳｉ3 Ｎ4 セラミックスであること
を特徴とする請求項４及び５のいずれにか記載の副室を
持つピストンの構造。6. The structure of a piston having a sub chamber according to claim 4, wherein the top portion of the piston of the sub chamber structure is Incoloy 903 or Si 3 N 4 ceramics. 【請求項７】 前記副室構造体は前記ピストン本体に鋳
込みによって配置されていることを特徴とする請求項１
〜６のいずれかに記載の副室を持つピストンの構造。7. The sub-chamber structure is arranged in the piston body by casting.
The structure of the piston which has the subchamber in any one of-6. 【請求項８】 前記副室構造体の外面と前記ピストン本
体の前記キャビティ壁面との間にはセラミックファイバ
ー又はＰＳＺ溶射層から成る遮熱材が介在されているこ
とを特徴とする請求項１〜７のいずれかに記載の副室を
持つピストンの構造。8. A heat shield made of a ceramic fiber or a PSZ sprayed layer is interposed between the outer surface of the sub chamber structure and the cavity wall surface of the piston body. 7. The structure of the piston having the sub chamber according to any one of 7.
JP6224008A 1994-08-26 1994-08-26 Structure of piston having auxiliary chamber Pending JPH0868330A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6224008A JPH0868330A (en) 1994-08-26 1994-08-26 Structure of piston having auxiliary chamber

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6224008A JPH0868330A (en) 1994-08-26 1994-08-26 Structure of piston having auxiliary chamber

Publications (1)

Publication Number Publication Date
JPH0868330A true JPH0868330A (en) 1996-03-12

Family

ID=16807149

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6224008A Pending JPH0868330A (en) 1994-08-26 1994-08-26 Structure of piston having auxiliary chamber

Country Status (1)

Country Link
JP (1) JPH0868330A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009024498A (en) * 2007-07-17 2009-02-05 Hino Motors Ltd Flexible joint structure of exhaust system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009024498A (en) * 2007-07-17 2009-02-05 Hino Motors Ltd Flexible joint structure of exhaust system

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