JP3832025B2 - Piston for direct-injection spark ignition internal combustion engine - Google Patents

Piston for direct-injection spark ignition internal combustion engine Download PDF

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Publication number
JP3832025B2
JP3832025B2 JP14492697A JP14492697A JP3832025B2 JP 3832025 B2 JP3832025 B2 JP 3832025B2 JP 14492697 A JP14492697 A JP 14492697A JP 14492697 A JP14492697 A JP 14492697A JP 3832025 B2 JP3832025 B2 JP 3832025B2
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Japan
Prior art keywords
piston
cavity
internal combustion
combustion engine
direct
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JP14492697A
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JPH10331644A (en
Inventor
宣久 神宮
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Nissan Motor Co Ltd
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Nissan Motor Co Ltd
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Priority to JP14492697A priority Critical patent/JP3832025B2/en
Application filed by Nissan Motor Co Ltd filed Critical Nissan Motor Co Ltd
Priority to US09/155,314 priority patent/US6129070A/en
Priority to PCT/JP1998/002271 priority patent/WO1998055743A1/en
Priority to EP98921783A priority patent/EP0916019B1/en
Priority to CN98800576XA priority patent/CN1083528C/en
Priority to DE69817731T priority patent/DE69817731T2/en
Priority to MYPI98002377A priority patent/MY125879A/en
Priority to TW087108307A priority patent/TW403810B/en
Publication of JPH10331644A publication Critical patent/JPH10331644A/en
Priority to KR1019997000908A priority patent/KR100305299B1/en
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Publication of JP3832025B2 publication Critical patent/JP3832025B2/en
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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
    • 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

Description

【０００１】
【発明の属する技術分野】
本発明は、直噴火花点火式内燃機関のピストンに関し、特にその冠面形状に関する。
【０００２】
【従来の技術】
従来の直噴火花点火式内燃機関のピストンにおいては、例えば特開平８−３１２３５４号公報に示されるように、その冠面に凹状でかつ周縁部が隆起して稜線をなすキャビティ（凹状燃焼室）を形成し、圧縮行程にてこのキャビティに向けて燃料を噴射することにより、点火栓回りに集中的に層状の混合気を形成して成層燃焼を行うようにしている。
【０００３】
また、機関運転条件により、吸気行程にて燃料を噴射することにより、燃焼室全体に燃料を拡散させ均質の混合気を形成して均質燃焼を行うようにしている。
【０００４】
【発明が解決しようとする課題】
しかしながら、従来の直噴火花点火式内燃機関のピストンにおいては、キャビティを囲む稜線の外周側、特にピストンの中心より吸気バルブ側にオフセットして設けられているキャビティの左右（クロスフロー方向と直角な方向にある部分）の稜線の外周側に、平坦部を設け、この平坦部の外側に傾斜面を設けていたため（前記公報の図７、図１１等参照）、この平坦部の部分が燃焼室全体から見ると、キャビティ内と外との間、更には吸気バルブ側周縁部と排気バルブ側周縁部との間に位置する凸壁となり、吸気行程噴射による均質燃焼を行う場合に、燃焼性能を悪化させるという問題点があった。
【０００５】
すなわち、均質燃焼を行う場合に、凸壁により、▲１▼キャビティ内に燃料噴霧が留まってしまうため、混合気が偏在し、均質混合気を形成できない。▲２▼筒内ガス流動が阻害されるため、燃料噴霧が気化せず、混合気の均質化が不十分となる。▲３▼燃焼中、キャビティ内と外との空間不連続により、キャビティ外側が良好に燃焼しない。これらにより、均質燃焼性能が悪化する。
【０００６】
本発明は、このような従来の問題点に鑑み、ピストンの冠面形状を工夫することにより、キャビティによる成層燃焼性能を悪化させることなく、均質燃焼性能を改善することを目的とする。
【０００７】
【課題を解決するための手段】
このため、請求項１に係る発明では、冠面に凹状でかつ周縁部が隆起して稜線をなすキャビティを有する直噴火花点火式内燃機関のピストンにおいて、前記キャビティは、その中心をピストンの中心に対し吸気バルブ側にオフセットして形成され、吸気バルブ側からキャビティ内を指向するように燃料噴射弁が配置されると共に、キャビティ内のピストン中心側の周縁部の上方に点火栓が配置され、前記稜線の外周側又は該稜線の少なくとも一部分を除く外周側に、平坦部を設けることなく、ピストンの外周部に向かって連続的に低くなる傾斜面を形成し、更に、前記キャビティのピストン中心側の周縁部の稜線の外周側に、前記傾斜面より緩傾斜の緩傾斜面を設けたことを特徴とする。
【０００８】
請求項２に係る発明では、前記傾斜面を１つの円錐面で形成したことを特徴とする。
請求項３に係る発明では、ピストン冠面の最外周部に前記傾斜面と連なる環状の基準平面を残したことを特徴とする。
請求項４に係る発明では、前記稜線の一部を切り欠いて吸排気バルブを逃げるバルブリセスを形成したことを特徴とする。
【００１０】
請求項５に係る発明では、シリンダボア円の投影面積をＳとし、ピストン上死点位置で、シリンダヘッドとピストン冠面とに囲まれる燃焼室のピストン中心線を含むクロスフロー方向と直角な平面での断面積のうちの稜線より外側の断面積をＳ２とすると、Ｓ２／Ｓを３０％以上にしたことを特徴とする。
【００１１】
【発明の効果】
請求項１に係る発明によれば、ピストン冠面のキャビティを囲む稜線の外周側に、平坦部を設けることなく、ピストンの外周部に向かって連続的に低くなる傾斜面を形成したので、キャビティ内と外との間、更には吸気バルブ側周縁部と排気バルブ側周縁部との間でのガス流動を確保できて、混合気の均質化を促進できると共に、ピストン表面積を低減して、冷却損失を低減でき、これらにより均質燃焼性能を向上できる。そして、キャビティ形状については変更しないので、成層燃焼性能を悪化させることはない。
また、キャビティの位置をオフセットして、燃料噴射弁及び点火栓との位置関係を最適化することができる。
更に、キャビティのピストン中心側の周縁部の稜線の外周側に、前記傾斜面より緩傾斜の緩傾斜面を設けたので、連続的な傾斜を確保しつつ、ピストンの最高部の高さを低減できる。
【００１２】
請求項２に係る発明によれば、前記傾斜面を１つの円錐面で形成するので、生産加工が容易となる。
請求項３に係る発明によれば、ピストン冠面の最外周部に前記傾斜面と連なる環状の基準平面を残したので、これを生産加工上の基準面として用いることで、生産加工が容易となる。
【００１３】
請求項４に係る発明によれば、稜線の一部を切り欠いてバルブリセスを形成するので、バルブリセス一般の効果としてバルブタイミングあるいは圧縮比の要求に応えることができるのみならず、平坦部を切り欠く場合に比べ、リセス部形状を小さくできると共に、ピストン表面積の増加が少なくて済む。
【００１４】
請求項５に係る発明によれば、前記Ｓ２／Ｓを３０％以上にして、キャビティ外側の燃焼空間を十分に確保することで、均質燃焼性能を向上させることができる。
【００１５】
【発明の実施の形態】
以下に本発明の実施の形態を図面に基づいて説明する。
図１は本発明の一実施例を示すピストン冠面の斜視図である。図２にはピストンの平面図とそのＡ−Ａ及びＢ−Ｂ断面図とを示している。また、図３は図２のＡ−Ａ断面に相当する図で燃料噴射弁及び点火栓の位置関係を示している。
【００１６】
ピストン１の冠面は、最外周側に環状の基準平面２を残して、傾斜面３により、円錐状に隆起させ、その隆起させた部分に、ピストンの中心ＰＣに対し吸気バルブ側にオフセットした位置ＣＣを中心にして、凹状（皿状）のキャビティ４を形成してある。
言い換えれば、キャビティ４を囲む稜線５の外周側に、平坦部を設けることなく、ピストン１の外周部に向かって連続的に低くなる傾斜面３を形成してあり、この傾斜面３は１つの円錐面で形成してある。
【００１７】
最外周側の環状の基準平面２は最小限の幅（１．５〜２．０ｍｍ程度）を持たせ、生産加工時に基準面として用いる。
また、キャビティ４のピストン中心側の周縁部の稜線５の外周側には、前記傾斜面３より緩傾斜の緩傾斜面６を設けて、ピストン１の最高部の高さを抑えてある。
【００１８】
ここで、キャビティ４と燃料噴射弁及び点火栓との位置関係は、図３に示すようであり、シリンダヘッド１０に吸気バルブ１１側からキャビティ４内を指向するように燃料噴射弁１２を配置すると共に、キャビティ４内のピストン中心側の周縁部の上方に点火栓１３を配置してある。１４は排気バルブである。
上記のように、ピストン１冠面のキャビティ４を囲む稜線５の外周側に、平坦部を設けることなく、ピストン１の外周部に向かって連続的に低くなる傾斜面３を形成したので、キャビティ４内と外との間、更には吸気バルブ１１側周縁部と排気バルブ１４側周縁部との間でのガス流動を確保でき、混合気の均質化を促進できる。また、平坦部を設けないので、ピストン１の表面積を低減でき、冷却損失を低減できる。よって、均質燃焼性能を向上できるのである。そして、キャビティ４そのものの形状については変更しないので、成層燃焼性能を悪化させることはない。
【００１９】
すなわち、図８及び図９に示す従来例では、平坦部２０の存在により、これが凸壁となって、ガス流動を阻害したりするが、これを解消できるのである。
図４及び図５には他の実施例を示している。
この実施例は、図１及び図２の実施例に対し、１気筒につき２個ある吸気バルブを逃げるバルブリセスを形成したもので、稜線５の一部を切り欠いて、バルブリセス７，７を形成してある。
【００２０】
このように、稜線５の一部を切り欠いてバルブリセス７を形成するので、バルブリセス７の一般的な効果としてバルブタイミングあるいは圧縮比の要求に応えることができるのみならず、図８及び図９の平坦部２０を切り欠く場合に比べ、リセス部形状を小さくできると共に、ピストン表面積の増加が少なくて済む。このため、バルブリセスによるピストン容積変化が少なく、圧縮比調整も容易となる。
【００２１】
ここで、図６を参照し、シリンダボア円の投影面積をＳとし、ピストン１の上死点位置で、シリンダヘッド１０とピストン１冠面とに囲まれる燃焼室のピストン中心線を含むクロスフロー方向と直角な平面（図６のＢ−Ｂ断面）での断面積のうちの、稜線５より外側の断面積をＳ２とすると、断面積比Ｓ２／Ｓを所定値以上にするのがよい。
【００２２】
図７は、断面積比Ｓ２／Ｓ（％）と均質燃焼時の軸トルクとの関係を示したもので、断面積比Ｓ２／Ｓ（％）が大になると、均質燃焼時軸トルクが増大することがわかる。
そして、この図から、Ｓ２／Ｓは３０％以上にするのがよい。上限は、成層燃焼性能との兼ね合いで決定されるが、５０％以上にしても、それ以上は均質燃焼性能を向上できないので、５０％程度が上限値となる。
【図面の簡単な説明】
【図１】 本発明の一実施例を示すピストン冠面の斜視図
【図２】 同上のピストンの平面図とそのＡ−Ａ及びＢ−Ｂ断面図
【図３】 燃料噴射弁及び点火栓の位置関係を示す図
【図４】 他の実施例（バルブリセス付き）を示すピストン冠面の斜視図
【図５】 同上のピストンの平面図とそのＡ−Ａ及びＢ−Ｂ断面図
【図６】 断面積について定義するための図
【図７】 断面積比と均質燃焼時軸トルクとの関係を示す図
【図８】 従来例を示すピストン冠面の斜視図
【図９】 同上のピストンの平面図とそのＡ−Ａ及びＢ−Ｂ断面図
【符号の説明】
１ ピストン
２ 基準平面
３ 傾斜面（円錐面）
４ キャビティ
５ 稜線
６ 緩傾斜面
７ バルブリセス
10 シリンダヘッド
11 吸気バルブ
12 燃料噴射弁
13 点火栓
14 排気バルブ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piston of a direct-injection spark-ignition internal combustion engine, and more particularly to its crown shape.
[0002]
[Prior art]
In a piston of a conventional direct-injection spark ignition internal combustion engine, for example, as disclosed in JP-A-8-31354, a cavity (concave combustion chamber) having a concave shape on its crown and a peripheral edge rising to form a ridgeline. , And by injecting fuel toward the cavity in the compression stroke, a stratified mixture is formed intensively around the spark plug to perform stratified combustion.
[0003]
Further, by injecting fuel in the intake stroke according to the engine operating conditions, the fuel is diffused throughout the combustion chamber to form a homogeneous air-fuel mixture and perform homogeneous combustion.
[0004]
[Problems to be solved by the invention]
However, in the piston of a conventional direct-injection spark ignition type internal combustion engine, the right and left sides of the cavity provided at the outer peripheral side of the ridge line surrounding the cavity, particularly the offset from the center of the piston to the intake valve side (perpendicular to the cross flow direction) Since the flat portion is provided on the outer peripheral side of the ridge line (the portion in the direction) and the inclined surface is provided outside the flat portion (see FIGS. 7 and 11, etc. of the publication), the flat portion is the combustion chamber. When viewed from the whole, it becomes a convex wall located between the inside and outside of the cavity, and further between the intake valve side periphery and the exhaust valve side periphery, and the combustion performance is improved when performing homogeneous combustion by intake stroke injection. There was a problem of making it worse.
[0005]
That is, when homogeneous combustion is performed, the fuel spray remains in the cavity due to the convex wall. Therefore, the air-fuel mixture is unevenly distributed and a homogeneous air-fuel mixture cannot be formed. (2) Since the in-cylinder gas flow is hindered, the fuel spray is not vaporized and the homogenization of the air-fuel mixture becomes insufficient. (3) During combustion, the outside of the cavity does not burn well due to the spatial discontinuity between the inside and outside of the cavity. As a result, the homogeneous combustion performance deteriorates.
[0006]
In view of such a conventional problem, an object of the present invention is to improve the homogeneous combustion performance without deteriorating the stratified combustion performance by the cavity by devising the shape of the crown surface of the piston.
[0007]
[Means for Solving the Problems]
Therefore, in the invention according to claim 1, in the piston of the direct-injection spark ignition internal combustion engine having a cavity that is concave on the crown surface and has a peripheral edge that protrudes and forms a ridgeline, the cavity is centered on the center of the piston. The fuel injection valve is formed so as to be offset toward the intake valve side and directed from the intake valve side to the inside of the cavity, and an ignition plug is disposed above the peripheral edge of the piston center side in the cavity. On the outer peripheral side of the ridge line or on the outer peripheral side excluding at least a part of the ridge line, an inclined surface that continuously decreases toward the outer peripheral part of the piston is formed without providing a flat part , and further, on the piston center side of the cavity A gradually inclined surface that is gentler than the inclined surface is provided on the outer peripheral side of the ridge line of the peripheral edge .
[0008]
The invention according to claim 2 is characterized in that the inclined surface is formed by one conical surface.
The invention according to claim 3 is characterized in that an annular reference plane connected to the inclined surface is left in the outermost peripheral portion of the piston crown surface.
The invention according to claim 4 is characterized in that a valve recess for escaping the intake / exhaust valve is formed by cutting out part of the ridgeline.
[0010]
In the invention according to claim 5 , the projected area of the cylinder bore circle is S, and at a piston top dead center position, a plane perpendicular to the cross flow direction including the piston center line of the combustion chamber surrounded by the cylinder head and the piston crown surface. If the cross-sectional area outside the ridge line in the cross-sectional area is S2, S2 / S is 30% or more.
[0011]
【The invention's effect】
According to the first aspect of the present invention, since the inclined surface that continuously decreases toward the outer peripheral portion of the piston is formed on the outer peripheral side of the ridge line surrounding the cavity of the piston crown surface without providing a flat portion, The gas flow between the inside and outside, as well as between the intake valve side periphery and the exhaust valve side periphery, can be ensured, the homogenization of the air-fuel mixture can be promoted, the piston surface area can be reduced, and cooling Loss can be reduced, and these can improve homogeneous combustion performance. And since it does not change about a cavity shape, stratified combustion performance is not deteriorated.
Further, the position of the cavity can be offset to optimize the positional relationship between the fuel injection valve and the spark plug.
In addition, a gentle slope that is gentler than the slope is provided on the outer peripheral side of the ridgeline at the peripheral edge of the piston center side of the cavity, so that the maximum height of the piston is reduced while ensuring a continuous slope. it can.
[0012]
According to the invention which concerns on Claim 2, since the said inclined surface is formed by one conical surface, production processing becomes easy.
According to the invention of claim 3, since an annular reference plane that is continuous with the inclined surface is left in the outermost peripheral portion of the piston crown surface, by using this as a reference plane in production processing, production processing is facilitated. Become.
[0013]
According to the invention of claim 4, since the valve recess is formed by cutting out a part of the ridgeline, not only can the valve timing or the compression ratio be satisfied as a general effect of the valve recess, but also the flat portion is cut out. Compared to the case, the recess shape can be reduced, and the increase in the piston surface area can be reduced.
[0014]
According to the fifth aspect of the present invention, homogeneous combustion performance can be improved by setting the S2 / S to 30% or more and ensuring a sufficient combustion space outside the cavity.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view of a piston crown surface showing an embodiment of the present invention. FIG. 2 shows a plan view of the piston and its AA and BB sectional views. FIG. 3 is a view corresponding to the AA cross section of FIG. 2 and shows the positional relationship between the fuel injection valve and the spark plug.
[0016]
The crown surface of the piston 1 is raised in a conical shape by the inclined surface 3 leaving the annular reference plane 2 on the outermost peripheral side, and the raised portion is offset toward the intake valve side with respect to the center PC of the piston. A concave (dish-shaped) cavity 4 is formed around the position CC.
In other words, the inclined surface 3 that continuously decreases toward the outer peripheral portion of the piston 1 is formed on the outer peripheral side of the ridge line 5 surrounding the cavity 4 without providing a flat portion. It is formed with a conical surface.
[0017]
The outermost annular reference plane 2 has a minimum width (about 1.5 to 2.0 mm) and is used as a reference plane during production processing.
Further, on the outer peripheral side of the ridge line 5 at the peripheral edge of the cavity 4 on the piston center side, a gently inclined surface 6 that is more gently inclined than the inclined surface 3 is provided to suppress the height of the highest portion of the piston 1.
[0018]
Here, the positional relationship between the cavity 4 and the fuel injection valve and the spark plug is as shown in FIG. 3, and the fuel injection valve 12 is arranged in the cylinder head 10 so as to face the cavity 4 from the intake valve 11 side. In addition, a spark plug 13 is disposed above the peripheral edge of the piston 4 in the cavity 4. Reference numeral 14 denotes an exhaust valve.
As described above, the inclined surface 3 continuously lowering toward the outer peripheral portion of the piston 1 is formed on the outer peripheral side of the ridge line 5 surrounding the cavity 4 on the crown surface of the piston 1 without providing a flat portion. 4, gas flow between the inside and outside, and further between the peripheral portion on the intake valve 11 side and the peripheral portion on the exhaust valve 14 side can be secured, and homogenization of the air-fuel mixture can be promoted. Further, since the flat portion is not provided, the surface area of the piston 1 can be reduced and the cooling loss can be reduced. Therefore, the homogeneous combustion performance can be improved. And since the shape of the cavity 4 itself is not changed, the stratified combustion performance is not deteriorated.
[0019]
That is, in the conventional example shown in FIGS. 8 and 9, the presence of the flat portion 20 becomes a convex wall and obstructs the gas flow, but this can be solved.
4 and 5 show another embodiment.
In this embodiment, a valve recess for escaping two intake valves per cylinder is formed with respect to the embodiment of FIGS. 1 and 2, and a part of the ridge 5 is cut away to form valve recesses 7 and 7. It is.
[0020]
As described above, since the valve recess 7 is formed by cutting out a part of the ridge 5, not only can the valve timing or the compression ratio be satisfied as a general effect of the valve recess 7, but also FIG. 8 and FIG. 9. Compared with the case where the flat portion 20 is notched, the recess portion shape can be reduced and the increase in the piston surface area can be reduced. For this reason, there is little piston volume change by a valve recess, and compression ratio adjustment becomes easy.
[0021]
Here, with reference to FIG. 6, the projected area of the cylinder bore circle is S, and the cross flow direction including the piston center line of the combustion chamber surrounded by the cylinder head 10 and the piston 1 crown surface at the top dead center position of the piston 1. Of the cross-sectional areas in the plane perpendicular to the cross-section (BB cross section in FIG. 6), the cross-sectional area ratio S2 / S should be a predetermined value or more, assuming that the cross-sectional area outside the ridge line 5 is S2.
[0022]
FIG. 7 shows the relationship between the cross-sectional area ratio S2 / S (%) and the axial torque during homogeneous combustion. When the cross-sectional area ratio S2 / S (%) increases, the homogeneous combustion axial torque increases. I understand that
From this figure, S2 / S is preferably 30% or more. The upper limit is determined in consideration of the stratified combustion performance, but even if it is 50% or more, the homogeneous combustion performance cannot be improved beyond that, so about 50% is the upper limit.
[Brief description of the drawings]
FIG. 1 is a perspective view of a crown surface of a piston showing an embodiment of the present invention. FIG. 2 is a plan view of the piston and AA and BB cross-sectional views thereof. FIG. 4 is a perspective view of a piston crown surface showing another embodiment (with a valve recess). FIG. 5 is a plan view of the same piston and its AA and BB sectional views. Fig. 7 is a diagram for defining the cross-sectional area. Fig. 7 is a diagram showing the relationship between the cross-sectional area ratio and the homogeneous combustion axial torque. Fig. 8 is a perspective view of a piston crown surface showing a conventional example. Figure and its AA and BB cross section
1 Piston 2 Reference plane 3 Inclined surface (conical surface)
4 Cavity 5 Ridge line 6 Slightly inclined surface 7 Valve recess
10 Cylinder head
11 Intake valve
12 Fuel injection valve
13 Spark plug
14 Exhaust valve

Claims (5)

冠面に凹状でかつ周縁部が隆起して稜線をなすキャビティを有する直噴火花点火式内燃機関のピストンにおいて、
前記キャビティは、その中心をピストンの中心に対し吸気バルブ側にオフセットして形成され、吸気バルブ側からキャビティ内を指向するように燃料噴射弁が配置されると共に、キャビティ内のピストン中心側の周縁部の上方に点火栓が配置され、
前記稜線の外周側又は該稜線の少なくとも一部分を除く外周側に、平坦部を設けることなく、ピストンの外周部に向かって連続的に低くなる傾斜面を形成し、
更に、前記キャビティのピストン中心側の周縁部の稜線の外周側に、前記傾斜面より緩傾斜の緩傾斜面を設けたことを特徴とする直噴火花点火式内燃機関のピストン。In a piston of a direct-injection spark ignition internal combustion engine having a cavity that is concave on the crown surface and has a ridge that is raised at the periphery,
The cavity is formed with its center offset to the intake valve side with respect to the center of the piston, and a fuel injection valve is disposed so as to be directed from the intake valve side into the cavity, and a peripheral edge of the piston center side in the cavity A spark plug is arranged above the section,
On the outer peripheral side of the ridge line or on the outer peripheral side excluding at least a part of the ridge line, without providing a flat part, an inclined surface that continuously decreases toward the outer peripheral part of the piston is formed ,
Further, the piston of the direct-injection spark-ignition internal combustion engine, characterized in that a gently inclined surface that is gentler than the inclined surface is provided on the outer peripheral side of the ridge line of the peripheral edge portion of the cavity center side of the cavity . 前記傾斜面を１つの円錐面で形成したことを特徴とする請求項１記載の直噴火花点火式内燃機関のピストン。  2. The piston of a direct injection spark ignition type internal combustion engine according to claim 1, wherein the inclined surface is formed by one conical surface. ピストン冠面の最外周部に前記傾斜面と連なる環状の基準平面を残したことを特徴とする請求項１又は請求項２記載の直噴火花点火式内燃機関のピストン。  The piston of the direct injection spark ignition type internal combustion engine according to claim 1 or 2, wherein an annular reference plane connected to the inclined surface is left in an outermost peripheral portion of a piston crown surface. 前記稜線の一部を切り欠いて吸排気バルブを逃げるバルブリセスを形成したことを特徴とする請求項１〜請求項３のいずれか１つに記載の直噴火花点火式内燃機関のピストン。  The piston of the direct-injection spark ignition type internal combustion engine according to any one of claims 1 to 3, wherein a valve recess is formed by notching a part of the ridge line to escape the intake / exhaust valve. シリンダボア円の投影面積をＳとし、ピストン上死点位置で、シリンダヘッドとピストン冠面とに囲まれる燃焼室のピストン中心線を含むクロスフロー方向と直角な平面での断面積のうちの稜線より外側の断面積をＳ２とすると、Ｓ２／Ｓを３０％以上にしたことを特徴とする請求項１〜請求項４のいずれか１つに記載の直噴火花点火式内燃機関のピストン。The projected area of the cylinder bore circle is S, and at the piston top dead center position, from the ridge line of the cross-sectional area in the plane perpendicular to the cross flow direction including the piston center line of the combustion chamber surrounded by the cylinder head and the piston crown surface The direct-injection spark-ignited internal combustion engine piston according to any one of claims 1 to 4 , wherein S2 / S is 30% or more, where S2 is an outer cross-sectional area.
JP14492697A 1997-06-03 1997-06-03 Piston for direct-injection spark ignition internal combustion engine Expired - Lifetime JP3832025B2 (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
JP14492697A JP3832025B2 (en) 1997-06-03 1997-06-03 Piston for direct-injection spark ignition internal combustion engine
PCT/JP1998/002271 WO1998055743A1 (en) 1997-06-03 1998-05-25 Piston for cylinder direct injection spark ignition internal combustion engine
EP98921783A EP0916019B1 (en) 1997-06-03 1998-05-25 Piston for cylinder direct injection spark ignition internal combustion engine
CN98800576XA CN1083528C (en) 1997-06-03 1998-05-25 Piston for cylinder direct injection spark ignition internal combustion engine
US09/155,314 US6129070A (en) 1997-06-03 1998-05-25 Piston for cylinder direct injection spark ignition internal combustion engine
DE69817731T DE69817731T2 (en) 1997-06-03 1998-05-25 PISTON FOR AN INTERNAL COMBUSTION ENGINE WITH DIRECT INJECTION AND IGNITION
MYPI98002377A MY125879A (en) 1997-06-03 1998-05-28 Piston for cylinder direct injection spark ignition internal combustion engine
TW087108307A TW403810B (en) 1997-06-03 1998-05-28 Piston for cylinder direct injection spark ignition internal combustion engine
KR1019997000908A KR100305299B1 (en) 1997-06-03 1999-02-02 Piston for cylinder direct injection spark ignition internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14492697A JP3832025B2 (en) 1997-06-03 1997-06-03 Piston for direct-injection spark ignition internal combustion engine

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JPH10331644A JPH10331644A (en) 1998-12-15
JP3832025B2 true JP3832025B2 (en) 2006-10-11

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