JP4107554B2 - Piston for in-cylinder internal combustion engine - Google Patents

Piston for in-cylinder internal combustion engine Download PDF

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Publication number
JP4107554B2
JP4107554B2 JP2001213264A JP2001213264A JP4107554B2 JP 4107554 B2 JP4107554 B2 JP 4107554B2 JP 2001213264 A JP2001213264 A JP 2001213264A JP 2001213264 A JP2001213264 A JP 2001213264A JP 4107554 B2 JP4107554 B2 JP 4107554B2
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combustion chamber
sub
piston
main
main combustion
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JP2003027944A (en
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城 史 隆 本
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UD Trucks Corp
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UD Trucks Corp
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    • 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
    • F02B75/00—Other engines
    • F02B75/12—Other methods of operation
    • F02B2075/125—Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-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
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/34—Lateral camshaft position
    • 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
    • F02B23/10—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder
    • F02B23/101—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder the injector being placed on or close to the cylinder centre axis, e.g. with mixture formation using spray guided concepts
    • 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
    • F02F2001/247—Arrangement of valve stems in cylinder heads the valve stems being orientated in parallel 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

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  • Combustion Methods Of Internal-Combustion Engines (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、筒内噴射式内燃機関のピストンに関する。
【０００２】
【従来の技術】
近年、ガス（例えば、圧縮天然ガス等）を燃料とした内燃機関、所謂「ガスエンジン」の普及が目覚ましい。又、燃費向上のため燃料を筒内に噴射する筒内噴射化、所謂「直噴エンジン化」も時代の趨勢である。
【０００３】
ところが、前記ガスエンジンではノッキングに対応するためにディーゼルエンジンに比べ圧縮比を大きく採れないという問題がある。
【０００４】
圧縮比を低く押さえるためには、上死点においてシリンダヘッドとピストンで形成されるトップクリアランスを大きくすれば良いが、トップクリアランスを大きくした場合には未燃炭化水素の発生という新たな問題を抱えることとなる。
【０００５】
更に、ガス燃料は液体燃料と異なり噴霧の貫徹力が弱く、成層燃焼させる場合、点火プラグ近傍まで燃料を導くことが困難である。
【０００６】
この様な問題のため、現時点でガスエンジンの筒内噴射化（直接噴射式ガスエンジン）は実用化に至っていない。
【０００７】
【発明が解決しようとする課題】
本発明は上述した従来の問題点に鑑みて提案されたものであり、圧縮比を必要以上に高めることなく、主室（主燃焼室：以降主燃焼室を主室と記載する）内に燃料を噴射し、該燃料を良好な流れをもって点火栓に導き、速やかに燃焼を開始せしめ、主室での燃焼エネルギを更に速やか且効率的に副室（副燃焼室：以降副燃焼室を副室と記載する）に伝播し、燃焼効率の良い筒内噴射式内燃機関のピストンの提供を目的としている。
【０００８】
【課題を解決するための手段】
本発明の筒内噴射式内燃機関のピストンは、頂部に主燃焼室と副燃焼室とを有する筒内噴射式内燃機関のピストンにおいて、前記内燃機関はガス燃料機関であって、前記ピストン（１）の頂部（２）は平らであり、上面形状が長円形状である主燃焼室（３）と楕円形状である副燃焼室（４）とがその長軸（３ａ、４ａ）を互に平行に、かつその深さが略同じに形成され、その主燃焼室（３）と副燃焼室（４）との間には主燃焼室（３）および副燃焼室（４）の深さより浅く前記長軸（４ａ）の直角方向に延びる複数の連絡通路（５）が形成されており、そしてピストン頂部（２）に対向するシリンダヘッド（７）に設けられた点火プラグ（８）は主燃焼室（３）を投影する領域の副燃焼室（４）寄りに位置し、燃料噴射インジェクタ（９）は主燃焼室（３）を投影する領域の副燃焼室（４）から遠ざかった領域に位置している。
または、本発明の筒内噴射式内燃機関のピストンは、前記内燃機関がガソリン機関であって、その頂部には前記形状の主および副燃焼室（３、４）が形成されている。
あるいは、ピストン頂部（２０）とシリンダヘッド（７０）との間にはペントルーフ形式の燃焼室が形成され、ピストンの頂部には前記形状の主および副燃焼室（３０、４０）が形成されている。
そして、本発明の筒内噴射式内燃機関のピストンは、前記内燃機関がディーゼル機関であって、その頂部（２）には前記形状の主および副燃焼室（３、４）が形成され、ピストン頂部（２）に対向するシリンダヘッド（７）に設けられた燃料噴射インジェクタ（９）は主燃焼室（３）を投影する領域のほぼ中央に位置している。
かかる構成を具備する本発明の筒内噴射式内燃機関のピストンによれば、副室を設けることにより、当該副室の容積の分だけ燃焼室の容積が増加するので、トップクリアランスを増加させること無く、圧縮比が下げられる。
その結果、圧縮比を下げてノッキングを防止すると共に、トップクリアランスを小さく抑えて未燃炭化水素の発生を防止することが出来る。
【０００９】
【発明の実施の形態】
以下、本発明の第１実施形態（ガス燃料エンジン対応）に関して、図１〜図６に基づき説明する。
図１および図２において、ピストン１の頂部２には略同じ深さで、上面形状が長円形の主室３と、楕円形の副室４がお互いの長軸３ａ（主室）、４ａ（副室）が平行となるように形成されている。そして、前記主室３と前記副室４の間には主室３、副室４の深さよりも浅く、前記長軸３ａに直角方向の３本の連絡通路５が形成されている。
尚、図１中、符号１０は吸・排気ポートを示す。
【００１０】
図３を参照して、前記主室３の断面は、前記副室４に近い縁３ｂでは反返り部３ｃを有し底部３ｄに接する様な円弧３ｅが形成されており、前記副室４の反対側の縁３ｆでは前記底部３ｄに滑らかに接する円弧状の傾斜部３ｇが形成されている。
【００１１】
一方、前記ピストン頂部２に対向するシリンダヘッド７は、前記主室３を投影する領域（長円形状の領域）であって、副室３に近い側には、点火プラグ８が設けてられている。
さらに、前記主室３を投影する領域（長円形状）で副室３に遠ざかった位置には、前記傾斜部３ｇと同じ方向に傾斜して燃料噴射インジェクタ９が設けられている。
【００１２】
ここで、前記主室３の上面形状は長円に限ったものではなく、楕円、若しくは長円と楕円を組合せた形状であっても良い。
また、前記副室４の上面形状は楕円に限ったものではなく、長円、若しくは楕円と長円を組合せた形状であっても良い。
【００１３】
また、前記連絡通路５の断面面積及び本数は、３本に限ったものではなく、燃料の種類、副室４の形状、ピストン１の直径に適した断面面積及び本数とするのが良い。
【００１４】
更に、前記主室３の傾斜部３ｇは必ずしも円弧である必要はないが、傾斜部３ｇと底部３ｄは円弧で滑らかに接続するのが噴霧Ｇを円滑に点火プラグに到達させる上で好ましい。
【００１５】
次に、図３〜図６を用いて作用（燃焼の過程）を説明する。
図３及び図４は、圧縮工程後期に不均一な燃料を噴射する所謂「成層燃焼」の場合である。
図３において、図示しない前工程で、図示しない吸気ポートから空気が吸入されており、圧縮工程の終了近くで圧縮空気で満たされた燃焼室２０内にインジェクタ８から燃料ガスＧが噴射される。
【００１６】
噴射された燃料ガスは、前記傾斜部３ｇから、前記底部３ｄ、円弧３ｅ、反返り部３ｃと移動し、既に充満し圧縮された空気と交じり合い、巻き込みながら点火プラグ８に至る。
【００１７】
図４に進み、点火プラグ８に至った空気と交じり合った燃料ガスＧＡは爆発的に燃焼を開始し、燃焼の炎は、前記連絡通路５を通過することにより絞られ、更に増速され前記副室４に流入する。そして、副室４では既に空気と交じり合った混合ガスＧＡに炎が伝播して一気に燃焼が進む。
【００１８】
図５及び図６は、予め燃料ガスと空気とが混合され、圧縮工程の前に燃焼室２０内に吸気される、所謂「予混合燃焼」の場合である。
図５において、予め燃料ガスと空気とが混合された燃焼室２０内の混合ガスＧＡは、圧縮され上死点近くにおいて点火プラグ８により着火し、先ず、主室３内の混合ガスＧＡが爆発的に燃焼する。
【００１９】
図６に進み、前記主室３内で燃焼を開始した混合ガスＧＡの一部は、前記連絡通路５を通過することにより絞られて、更に増速して副室４側に伝播し、副室４内の混合ガスＧＡを瞬時に燃焼に導く。
【００２０】
係る機構を具備する本発明によれば、副室を設けることにより、燃焼室の容積が増し、トップクリアランスを増やすことなく圧縮比が下げられる。
【００２１】
トップクリアランスが増加しないので、未燃炭化水素、所謂「ＵＨＣ」の発生の懸念が無い。
【００２２】
主室と副室を連絡する連絡通路を設けたことにより、主室での燃焼エネルギは連絡通路によって絞られるために更に運動エネルギを与えられ、燃焼エネルギを速やか且効率的に副室に伝播できる。
従って、燃焼室全体では迅速且高効率な燃焼が行える。
【００２３】
図７は、本発明の第２実施形態であり、対応する燃料がガソリンで或ることを除けば作用・効果を含めて、第１実施形態（図３）と全て同じであるので以降の説明を省略する。
【００２４】
図８は、本発明の第３実施形態であり、ガソリン燃料でペントルーフタイプのシリンダヘッドを有するエンジンに対応し、予混合燃焼の場合の作動状態を示す状態図である。
シリンダヘッド７０及びこれに対応するピストン頂部２０に設けられた主室３０と副室４０の形状は異なるが、機能その他に関しては凡そ第１実施例（図３）に類似であるので以降の説明を省略する。
【００２５】
図９は、本発明の第４実施形態であり、ディーゼル燃料に対応し、成層燃焼の場合の作動状態を示す状態図である。
シリンダヘッド７５から点火プラグを排除し、ピストン頂部２５に設けられた主室３５の形状が異なる他は、凡そ第１実施形態（図３）に同様であるので以降の説明を省略する。
【００２６】
係る機構を具備する本発明のによれば、副室を設けることにより、燃焼室の容積が増し、トップクリアランスを増やすことなく圧縮比が下げられる。
【００２７】
トップクリアランスが増加しないので、未燃炭化水素の発生の懸念が無い。
【００２８】
主室と副室を連絡する連絡通路を設けたことにより、主室での燃焼エネルギに連絡通路における絞り効果で、更に運動エネルギを与えられ燃焼エネルギを速やか且効率的に副室に伝播できる。
【００２９】
従って、燃焼室全体では迅速且高効率な燃焼が行える。
【００３０】
図示の実施形態はあくまでも例示であり、本発明の技術的範囲を限定する趣旨の記述ではない旨を付記する。
ＬＰガスやジメチルエーテル等の揮発性が高く液体噴射された直後にガス化するような燃料にも適用できる。
【００３１】
【発明の効果】
本発明の作用効果を以下に列記する。
（ａ） 副室を設けることにより、燃焼室の容積が増し、トップクリアランスを増やすことなく圧縮比が下げられる。
（ｂ） トップクリアランスが増加しないので、未燃炭化水素の発生が防止される。
（ｃ） 主室と副室を連絡する連絡通路を設けたことにより、主室での燃焼エネルギに連絡通路における絞り効果で、更に運動エネルギを与えられ、燃焼エネルギを速やか且効率的に副室に伝播出来る。
（ｄ） 予混合燃焼の場合、連絡通路を介して副室へ火炎が伝播するので、燃焼室全体では迅速且つ高効率な燃焼が行える。
【図面の簡単な説明】
【図１】本発明のピストンを含むシリンダヘッドの要部構成を示す断面図。
【図２】本発明の第１実施形態（ガス燃料エンジン対応）のピストン上面図。
【図３】本発明の第１実施形態であり、成層燃焼の場合の作動状態を示すもので、燃料噴射直後の状態図。
【図４】本発明の第１実施形であり、態成層燃焼の場合の作動状態を示すもので、燃料が点火プラグに至り燃焼（爆発）を開始した直後の状態図。
【図５】本発明の第１実施形態であり、予混合燃焼の場合の作動状態を示すもので、燃焼（爆発）直後の状態図。
【図６】本発明の第１実施形態であり、予混合燃焼の場合の作動状態を示すもので、主室内で燃焼した燃焼エネルギを連絡通路を通して副室に伝播させ、副室内の圧縮燃料を燃焼させている状態図。
【図７】本発明の第２実施形態であり（ガソリン燃料で平らなシリンダヘッドを有するエンジンに対応）、予混合燃焼の場合の作動状態を示す状態図。
【図８】本発明の第３実施形態であり（ガソリン燃料でペントルーフタイプのシリンダヘッドを有するエンジンに対応）、予混合燃焼の場合の作動状態を示す状態図。
【図９】本発明の第４実施形態であり（ディーゼル燃料対応）、成層燃焼の場合の作動状態を示す状態図。
【符号の説明】
１・・・ピストン
２・・・ピストン頂部
３・・・主室
４・・・副室
５・・・レベリングバルブ位置検出手段
５・・・連絡通路
６・・・シリンダ
７・・・シリンダヘッド
８・・・点火プラグ
９・・・燃料インジェクタ
１０・・・吸・排気バルブ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piston of a direct injection internal combustion engine.
[0002]
[Prior art]
In recent years, an internal combustion engine using a gas (for example, compressed natural gas) as a fuel, so-called “gas engine”, has been remarkably spread. In addition, in-cylinder injection in which fuel is injected into a cylinder in order to improve fuel efficiency, so-called “direct injection engine” is also a trend of the times.
[0003]
However, the gas engine has a problem that a compression ratio cannot be increased as compared with a diesel engine in order to cope with knocking.
[0004]
In order to keep the compression ratio low, it is sufficient to increase the top clearance formed by the cylinder head and piston at the top dead center, but if the top clearance is increased, there is a new problem of generating unburned hydrocarbons. It will be.
[0005]
Furthermore, unlike liquid fuel, gas fuel has a weak spray penetration force, and when stratified combustion is performed, it is difficult to guide the fuel to the vicinity of the spark plug.
[0006]
Due to such problems, in-cylinder injection of a gas engine (direct injection type gas engine) has not yet been put into practical use.
[0007]
[Problems to be solved by the invention]
The present invention has been proposed in view of the above-described conventional problems, and fuel is contained in a main chamber (main combustion chamber: hereinafter, the main combustion chamber is referred to as a main chamber) without increasing the compression ratio more than necessary. The fuel is guided to the spark plug with a good flow, and combustion is quickly started, and the combustion energy in the main chamber is more quickly and efficiently sub-chamber (sub-combustion chamber: hereinafter referred to as sub-combustion chamber). It is an object of the present invention to provide a piston for a cylinder injection internal combustion engine with good combustion efficiency.
[0008]
[Means for Solving the Problems]
The piston of the cylinder injection internal combustion engine of the present invention is a piston of a cylinder injection internal combustion engine having a main combustion chamber and a sub-combustion chamber at the top. The internal combustion engine is a gas fuel engine, and the piston (1 ) Is flat, and the main combustion chamber (3) having an oval upper surface shape and the auxiliary combustion chamber (4) having an elliptical shape have their long axes (3a, 4a) parallel to each other. And the depth thereof is substantially the same, and the depth between the main combustion chamber (3) and the auxiliary combustion chamber (4) is shallower than the depth of the main combustion chamber (3) and the auxiliary combustion chamber (4). A plurality of communication passages (5) extending in a direction perpendicular to the long axis (4a) are formed, and a spark plug (8) provided in a cylinder head (7) facing the piston top (2) is a main combustion chamber. The fuel injection injector (9) is located near the sub-combustion chamber (4) in the region where (3) is projected. It is located moves away from the auxiliary combustion chamber in the region projecting combustion chamber (3) (4) region.
Alternatively, in the piston of the direct injection internal combustion engine of the present invention, the internal combustion engine is a gasoline engine, and the main and auxiliary combustion chambers (3, 4) having the above shape are formed at the top.
Alternatively, a pent roof type combustion chamber is formed between the piston top (20) and the cylinder head (70), and the main and auxiliary combustion chambers (30, 40) having the above-described shape are formed at the top of the piston. .
The piston of the in-cylinder internal combustion engine of the present invention is such that the internal combustion engine is a diesel engine, and the top and the top (2) are formed with the main and auxiliary combustion chambers (3, 4) having the shape described above. The fuel injection injector (9) provided in the cylinder head (7) facing the top (2) is located substantially at the center of the region projecting the main combustion chamber (3).
According to the piston of the direct injection internal combustion engine of the present invention having such a configuration, by providing the sub chamber, the volume of the combustion chamber increases by the volume of the sub chamber, so that the top clearance is increased. There is no compression ratio.
As a result, the compression ratio can be lowered to prevent knocking, and the top clearance can be kept small to prevent the generation of unburned hydrocarbons.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment (corresponding to a gas fuel engine) of the present invention will be described with reference to FIGS.
1 and 2, the top portion 2 of the piston 1 has substantially the same depth, and a main chamber 3 having an oval upper surface shape and an elliptical sub chamber 4 having long axes 3a (main chamber), 4a ( The sub chambers) are formed in parallel. Between the main chamber 3 and the sub chamber 4, three communication passages 5 are formed which are shallower than the main chamber 3 and the sub chamber 4, and are perpendicular to the long axis 3a.
In FIG. 1, reference numeral 10 denotes an intake / exhaust port.
[0010]
Referring to FIG. 3, the cross section of the main chamber 3 is formed with an arc 3 e having a reflex portion 3 c at the edge 3 b close to the sub chamber 4 so as to be in contact with the bottom 3 d. An arcuate inclined portion 3g that smoothly contacts the bottom portion 3d is formed at the opposite edge 3f.
[0011]
On the other hand, the cylinder head 7 facing the piston top 2 is a region (oval region) projecting the main chamber 3, and a spark plug 8 is provided on the side close to the sub chamber 3. Yes.
Further, a fuel injection injector 9 is provided at a position away from the sub chamber 3 in a region (oval shape) projecting the main chamber 3 and inclined in the same direction as the inclined portion 3g.
[0012]
Here, the shape of the upper surface of the main chamber 3 is not limited to an ellipse, but may be an ellipse or a combination of an ellipse and an ellipse.
Further, the shape of the upper surface of the sub chamber 4 is not limited to an ellipse, and may be an ellipse or a combination of an ellipse and an ellipse.
[0013]
Further, the cross-sectional area and the number of the communication passages 5 are not limited to three, but may be a cross-sectional area and the number suitable for the type of fuel, the shape of the sub chamber 4, and the diameter of the piston 1.
[0014]
Further, the inclined portion 3g of the main chamber 3 is not necessarily an arc, but it is preferable that the inclined portion 3g and the bottom portion 3d are smoothly connected with each other in order to make the spray G smoothly reach the spark plug.
[0015]
Next, the action (combustion process) will be described with reference to FIGS.
3 and 4 show the case of so-called “stratified combustion” in which non-uniform fuel is injected in the latter stage of the compression process.
In FIG. 3, air is sucked from an intake port (not shown) in a previous process (not shown), and fuel gas G is injected from the injector 8 into the combustion chamber 20 filled with compressed air near the end of the compression process.
[0016]
The injected fuel gas moves from the inclined portion 3g to the bottom portion 3d, the arc 3e, and the rebound portion 3c, mixes with the already filled and compressed air, and reaches the spark plug 8 while being entrained.
[0017]
Proceeding to FIG. 4, the fuel gas GA mixed with the air reaching the spark plug 8 starts to explosively combust, and the flame of combustion is throttled by passing through the communication passage 5, and is further increased in speed. It flows into the sub chamber 4. In the sub chamber 4, the flame propagates to the mixed gas GA that has already mixed with air, and the combustion proceeds at once.
[0018]
5 and 6 show a case of so-called “premixed combustion” in which fuel gas and air are mixed in advance and sucked into the combustion chamber 20 before the compression step.
In FIG. 5, the mixed gas GA in the combustion chamber 20 in which the fuel gas and air are mixed in advance is compressed and ignited by the spark plug 8 near the top dead center. First, the mixed gas GA in the main chamber 3 explodes. Burns.
[0019]
Proceeding to FIG. 6, a part of the mixed gas GA that has started to burn in the main chamber 3 is throttled by passing through the communication passage 5, further increased in speed, and propagated to the sub chamber 4 side. The mixed gas GA in the chamber 4 is instantaneously guided to combustion.
[0020]
According to the present invention having such a mechanism, by providing the sub chamber, the volume of the combustion chamber is increased, and the compression ratio is decreased without increasing the top clearance.
[0021]
Since the top clearance does not increase, there is no concern about the generation of unburned hydrocarbons, so-called “UHC”.
[0022]
By providing a communication passage that connects the main chamber and the sub chamber, the combustion energy in the main chamber is reduced by the communication passage, so that further kinetic energy can be given and the combustion energy can be quickly and efficiently transmitted to the sub chamber. .
Accordingly, the combustion chamber as a whole can be burned quickly and efficiently.
[0023]
FIG. 7 shows a second embodiment of the present invention, which is the same as the first embodiment (FIG. 3), including the effects and effects, except that the corresponding fuel is gasoline. Is omitted.
[0024]
FIG. 8 shows a third embodiment of the present invention, corresponding to an engine having a pent roof type cylinder head with gasoline fuel, and is a state diagram showing an operating state in the case of premixed combustion.
Although the shapes of the main chamber 30 and the sub chamber 40 provided in the cylinder head 70 and the corresponding piston top 20 are different, the functions and the like are similar to those of the first embodiment (FIG. 3), so the following description will be given. Omitted.
[0025]
FIG. 9 shows a fourth embodiment of the present invention and is a state diagram corresponding to diesel fuel and showing an operating state in the case of stratified combustion.
Since the spark plug is excluded from the cylinder head 75 and the shape of the main chamber 35 provided at the piston top 25 is different, the description is omitted since it is the same as that of the first embodiment (FIG. 3).
[0026]
According to the present invention having such a mechanism, by providing the sub chamber, the volume of the combustion chamber is increased, and the compression ratio is decreased without increasing the top clearance.
[0027]
Since the top clearance does not increase, there is no concern about the generation of unburned hydrocarbons.
[0028]
By providing the communication passage for connecting the main chamber and the sub chamber, the combustion energy in the main chamber can be further imparted to the combustion energy by the squeezing effect in the communication passage so that kinetic energy can be given to the sub chamber.
[0029]
Accordingly, the combustion chamber as a whole can be burned quickly and efficiently.
[0030]
It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
The present invention can also be applied to fuels such as LP gas and dimethyl ether that have high volatility and are gasified immediately after liquid injection.
[0031]
【The invention's effect】
The effects of the present invention are listed below.
(A) By providing the sub chamber, the volume of the combustion chamber is increased, and the compression ratio is lowered without increasing the top clearance.
(B) Since the top clearance does not increase, generation of unburned hydrocarbons is prevented.
(C) By providing a communication passage that connects the main chamber and the sub chamber, the combustion energy in the main chamber is further reduced by the squeezing effect in the communication passage, so that kinetic energy can be given quickly and efficiently. Can be propagated to.
(D) In the case of premixed combustion, the flame propagates to the sub chamber through the communication passage, so that the combustion chamber as a whole can perform rapid and highly efficient combustion.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main configuration of a cylinder head including a piston according to the present invention.
FIG. 2 is a top view of a piston according to the first embodiment (corresponding to a gas fuel engine) of the present invention.
FIG. 3 is a first embodiment of the present invention and shows an operating state in the case of stratified combustion, and is a state diagram immediately after fuel injection.
FIG. 4 is a first embodiment of the present invention and shows an operating state in the case of stratified combustion, and is a state diagram immediately after the fuel reaches the spark plug and starts combustion (explosion).
FIG. 5 is a first embodiment of the present invention, showing an operating state in the case of premixed combustion, and a state diagram immediately after combustion (explosion).
FIG. 6 is a first embodiment of the present invention and shows an operating state in the case of premixed combustion, in which combustion energy burned in the main chamber is propagated to the sub chamber through the communication passage, and the compressed fuel in the sub chamber is The state figure which is making it burn.
FIG. 7 is a state diagram showing an operating state in the case of premixed combustion according to a second embodiment of the present invention (corresponding to an engine having a flat cylinder head made of gasoline fuel).
FIG. 8 is a state diagram showing an operating state in the case of premixed combustion according to a third embodiment of the present invention (corresponding to an engine having a pent roof type cylinder head made of gasoline fuel).
FIG. 9 is a state diagram showing an operating state in the case of stratified combustion, which is the fourth embodiment of the present invention (corresponding to diesel fuel).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Piston 2 ... Piston top part 3 ... Main chamber 4 ... Sub chamber 5 ... Leveling valve position detection means 5 ... Communication passage 6 ... Cylinder 7 ... Cylinder head 8 ... Spark plug 9 ... Fuel injector 10 ... Suction / exhaust valve

Claims (4)

頂部に主燃焼室と副燃焼室とを有する筒内噴射式内燃機関のピストンにおいて、前記内燃機関はガス燃料機関であって、前記ピストン（１）の頂部（２）は平らであり、上面形状が長円形状である主燃焼室（３）と楕円形状である副燃焼室（４）とがその長軸（３ａ、４ａ）を互に平行に、かつその深さが略同じに形成され、その主燃焼室（３）と副燃焼室（４）との間には主燃焼室（３）および副燃焼室（４）の深さより浅く前記長軸（４ａ）の直角方向に延びる複数の連絡通路（５）が形成されており、そしてピストン頂部（２）に対向するシリンダヘッド（７）に設けられた点火プラグ（８）は主燃焼室（３）を投影する領域の副燃焼室（４）寄りに位置し、燃料噴射インジェクタ（９）は主燃焼室（３）を投影する領域の副燃焼室（４）から遠ざかった領域に位置していることを特徴とする筒内噴射式内燃機関のピストン。In a piston of a direct injection internal combustion engine having a main combustion chamber and a sub-combustion chamber at the top, the internal combustion engine is a gas fuel engine, and the top (2) of the piston (1) is flat and has a top shape. The main combustion chamber (3) having an oval shape and the sub-combustion chamber (4) having an elliptical shape are formed so that their long axes (3a, 4a) are parallel to each other and have substantially the same depth. Between the main combustion chamber (3) and the sub-combustion chamber (4), a plurality of connections extending in the direction perpendicular to the major axis (4a) is shallower than the main combustion chamber (3) and the sub-combustion chamber (4). A passage (5) is formed, and a spark plug (8) provided in a cylinder head (7) facing the piston top (2) is a sub-combustion chamber (4) in a region projecting the main combustion chamber (3). ) And the fuel injection injector (9) is located in the sub-combustion chamber (in the region that projects the main combustion chamber (3)). The piston of the direct injection internal combustion engine, characterized in that located away area from). 頂部に主燃焼室と副燃焼室とを有する筒内噴射式内燃機関のピストンにおいて、前記内燃機関はガソリン機関であって、前記ピストン（１）の頂部（２）は平らであり、上面形状が長円形状である主燃焼室（３）と楕円形状である副燃焼室（４）とがその長軸（３ａ、４ａ）を互に平行に、かつその深さが略同じに形成され、その主燃焼室（３）と副燃焼室（４）との間には主燃焼室（３）および副燃焼室（４）の深さより浅く前記長軸（４ａ）の直角方向に延びる複数の連絡通路（５）が形成されており、そしてピストン頂部（２）に対向するシリンダヘッド（７）に設けられた点火プラグ（８）は主燃焼室（３）を投影する領域の副燃焼室（４）寄りに位置し、燃料噴射インジェクタ（９）は主燃焼室（３）を投影する領域の副燃焼室（４）から遠ざかった領域に位置していることを特徴とする筒内噴射式内燃機関のピストン。In a piston of a direct injection internal combustion engine having a main combustion chamber and a sub-combustion chamber at the top, the internal combustion engine is a gasoline engine, the top (2) of the piston (1) is flat, and the top surface shape is The main combustion chamber (3) having an elliptical shape and the sub-combustion chamber (4) having an elliptical shape are formed so that their long axes (3a, 4a) are parallel to each other and have substantially the same depth. Between the main combustion chamber (3) and the sub-combustion chamber (4), there are a plurality of communication passages that are shallower than the main combustion chamber (3) and the sub-combustion chamber (4) and extend in the direction perpendicular to the long axis (4a). (5) is formed, and the spark plug (8) provided in the cylinder head (7) facing the piston top (2) is a sub-combustion chamber (4) in a region projecting the main combustion chamber (3). The fuel injection injector (9) is located closer to the sub-combustion chamber (in the region that projects the main combustion chamber (3)). The piston of the direct injection internal combustion engine, characterized in that located away area from). 頂部に主燃焼室と副燃焼室とを有する筒内噴射式内燃機関のピストンにおいて、前記内燃機関はガソリン機関であって、ピストン頂部（２０）とシリンダヘッド（７０）との間にはペントルーフ形式の燃焼室が形成され、前記ピストン（１０）の頂部（２０）には上面形状が長円形状である主燃焼室（３０）と楕円形状である副燃焼室（４０）とがその長軸を互に平行に、かつその深さが略同じに形成され、その主燃焼室（３０）と副燃焼室（４０）との間には主燃焼室（３０）および副燃焼室（４０）の深さより浅く前記長軸の直角方向に延びる複数の連絡通路（５）が形成されており、そしてピストン頂部（２０）に対向するシリンダヘッド（７０）に設けられた点火プラグ（８）は主燃焼室（３０）を投影する領域の副燃焼室（４０）寄りに位置し、燃料噴射インジェクタ（９）は主燃焼室（３０）を投影する領域の副燃焼室（４０）から遠ざかった領域に位置していることを特徴とする筒内噴射式内燃機関のピストン。In a piston of a direct injection internal combustion engine having a main combustion chamber and a sub-combustion chamber at the top, the internal combustion engine is a gasoline engine, and a pent roof type is provided between the piston top (20) and the cylinder head (70). The main combustion chamber (30) having an elliptical top surface and the sub-combustion chamber (40) having an elliptical shape have the major axis at the top (20) of the piston (10). The depths of the main combustion chamber (30) and the auxiliary combustion chamber (40) are between the main combustion chamber (30) and the auxiliary combustion chamber (40). A plurality of communication passages (5) extending in the direction perpendicular to the major axis is formed, and a spark plug (8) provided on the cylinder head (70) facing the piston top (20) is provided in the main combustion chamber. Sub-combustion chamber (40) in the region to project (30) The fuel injection injector (9) is located in a region away from the sub-combustion chamber (40) in the region where the main combustion chamber (30) is projected. piston. 頂部に主燃焼室と副燃焼室とを有する筒内噴射式内燃機関のピストンにおいて、前記内燃機関はディーゼル機関であって、前記ピストン（１）の頂部（２）は平らであり、上面形状が長円形状である主燃焼室（３）と楕円形状である副燃焼室（４）とがその長軸（３ａ、４ａ）を互に平行に、かつその深さが略同じに形成され、その主燃焼室（３）と副燃焼室（４）との間には主燃焼室（３）および副燃焼室（４）の深さより浅く前記長軸（４ａ）の直角方向に延びる複数の連絡通路（５）が形成されており、そしてピストン頂部（２）に対向するシリンダヘッド（７）に設けられた燃料噴射インジェクタ（９）は主燃焼室（３）を投影する領域のほぼ中央に位置していることを特徴とする筒内噴射式内燃機関のピストン。In a piston of a direct injection internal combustion engine having a main combustion chamber and a sub-combustion chamber at the top, the internal combustion engine is a diesel engine, the top (2) of the piston (1) is flat, and the top surface shape is The oval main combustion chamber (3) and the oval sub combustion chamber (4) are formed so that their long axes (3a, 4a) are parallel to each other and substantially the same depth. A plurality of communication passages between the main combustion chamber (3) and the sub-combustion chamber (4), which are shallower than the main combustion chamber (3) and the sub-combustion chamber (4) and extend in the direction perpendicular to the long axis (4a). (5) is formed, and the fuel injection injector (9) provided in the cylinder head (7) facing the piston top (2) is located at the approximate center of the region projecting the main combustion chamber (3). A piston for an in-cylinder injection internal combustion engine.
JP2001213264A 2001-07-13 2001-07-13 Piston for in-cylinder internal combustion engine Expired - Fee Related JP4107554B2 (en)

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