JP2000282870A - Cylinder injection type spark ignition internal combustion engine - Google Patents

Cylinder injection type spark ignition internal combustion engine

Info

Publication number
JP2000282870A
JP2000282870A JP11085938A JP8593899A JP2000282870A JP 2000282870 A JP2000282870 A JP 2000282870A JP 11085938 A JP11085938 A JP 11085938A JP 8593899 A JP8593899 A JP 8593899A JP 2000282870 A JP2000282870 A JP 2000282870A
Authority
JP
Japan
Prior art keywords
fuel
cavity
internal combustion
combustion engine
side wall
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
JP11085938A
Other languages
Japanese (ja)
Inventor
Yasuhito Tsutsumi
泰人 堤
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.)
Toyota Motor Corp
Original Assignee
Toyota Motor Corp
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 Toyota Motor Corp filed Critical Toyota Motor Corp
Priority to JP11085938A priority Critical patent/JP2000282870A/en
Publication of JP2000282870A publication Critical patent/JP2000282870A/en
Pending legal-status Critical Current

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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
    • F02B23/08—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
    • F02B23/104—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 a side position of the cylinder
    • 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
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F2001/244—Arrangement of valve stems in cylinder heads
    • F02F2001/245—Arrangement of valve stems in cylinder heads the valve stems being orientated at an angle with the cylinder axis
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Abstract

PROBLEM TO BE SOLVED: To make liquid fuel difficult to stick to an ignition plug in the case that injected fuel is not sufficiently vaporized in a cylinder injection type spark internal combustion engine, which leads the fuel injected in the recessed cavity formed on the top of a piston near the ignition plug along the contour of the cavity. SOLUTION: This internal combustion engine is provided with a cavity 8, which is formed on the top of a piston 5, an ignition plug 6 facing inwardly of the cavity 8, and a fuel injection valve enabling fuel injection into the cavity. The cavity 8 has a sidewall 8b opposing to the fuel injection valve to lead the fuel vaporized in the cavity 8 near the ignition plug 6, and the sidewall 8b is provided with a step section 8c projected in the internal direction of the cavity 8.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、筒内噴射式火花点
火内燃機関に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct injection spark ignition internal combustion engine.

【０００２】[0002]

【従来の技術】気筒内へ直接的に燃料を噴射することに
より、点火時点において点火プラグ近傍だけに着火性の
良好な濃度の混合気（以下、可燃混合気と称する）を形
成し、気筒内全体としては希薄な混合気の燃焼を可能に
する成層燃焼が公知である。成層燃焼を実施する際に
は、一般的に、圧縮行程後半において、燃料噴射弁から
ピストン頂面に形成された凹状の燃焼室内へ燃料が噴射
される。この燃料は、燃焼室壁面から熱を奪って徐々に
気化しながら燃焼室形状によって点火プラグ近傍へ偏向
される。こうして、点火時点において、点火プラグ近傍
に可燃混合気を形成することが意図されている。2. Description of the Related Art By injecting fuel directly into a cylinder, an air-fuel mixture having good ignitability (hereinafter referred to as a combustible air-fuel mixture) is formed only near the spark plug at the time of ignition, and is formed in the cylinder. Stratified combustion, which generally enables the combustion of lean mixtures, is known. When performing stratified combustion, fuel is generally injected from a fuel injection valve into a concave combustion chamber formed on the piston top surface in the latter half of the compression stroke. The fuel is deflected to the vicinity of the spark plug by the shape of the combustion chamber while gradually evaporating by taking heat from the wall of the combustion chamber. Thus, it is intended to form a combustible mixture near the spark plug at the time of ignition.

【０００３】[0003]

【発明が解決しようとする課題】一般的な燃料噴射弁は
燃料を円錐状に噴射するものである。このように噴射さ
れた燃料は、燃料噴射量が比較的多い場合に、噴射され
た燃料の一部が十分に気化せずに点火プラグ近傍へ向か
う可能性がある。こうして、この液状燃料が点火プラグ
の点火ギャップに付着して失火を発生させることがあ
る。A general fuel injection valve injects fuel in a conical shape. When the fuel injection amount is relatively large, a part of the injected fuel may not be sufficiently vaporized and may go to the vicinity of the ignition plug. Thus, the liquid fuel may adhere to the ignition gap of the spark plug and cause misfire.

【０００４】特開平９−１５８７３６号公報には、燃料
噴射弁の噴孔をスリット状にして燃料を比較的厚さの薄
い平らな扇状に噴射することが提案されている。こうし
て噴射された燃料は、広範囲の燃焼室壁面から熱を奪え
るために、円錐状の燃料噴霧に比較して容易に気化させ
ることができる。しかしながら、成層燃焼領域におい
て、機関負荷が増大して燃料噴射量が比較的多くなった
直後には、ピストン温度が低くて噴射された全ての燃料
を完全に気化させることができないことがあり、このよ
うな場合に、前述同様、失火発生の可能性がある。Japanese Patent Application Laid-Open No. 9-158736 proposes that the fuel injection valve is formed into a slit-like injection hole and the fuel is injected in a flat fan shape having a relatively small thickness. The fuel injected in this manner can be easily vaporized as compared with a conical fuel spray because heat can be removed from a wide range of combustion chamber wall surfaces. However, in the stratified combustion region, immediately after the engine load increases and the fuel injection amount becomes relatively large, the piston temperature may be low and not all the injected fuel may be completely vaporized. In such a case, there is a possibility that a misfire may occur as described above.

【０００５】従って、本発明の目的は、ピストン頂面に
形成された凹状のキャビティ内に噴射された燃料をキャ
ビティ形状によって点火プラグ近傍に導く筒内噴射式火
花点火内燃機関において、噴射された燃料が十分に気化
しない場合に、液状燃料が点火プラグに付着し難くする
ことである。Accordingly, an object of the present invention is to provide an in-cylinder spark ignition type internal combustion engine in which fuel injected into a concave cavity formed on the top surface of a piston is guided to the vicinity of an ignition plug by a cavity shape. If the fuel gas is not sufficiently vaporized, the liquid fuel hardly adheres to the spark plug.

【０００６】[0006]

【課題を解決するための手段】本発明による請求項１に
記載の筒内噴射式火花点火内燃機関は、ピストン頂面に
形成されたキャビティと、前記キャビティ内に臨む点火
プラグと、前記キャビティ内へ燃料を噴射することを可
能とする燃料噴射弁とを具備し、前記キャビティは、前
記キャビティ内で気化した燃料を前記点火プラグ近傍へ
導くために、前記燃料噴射弁に対向する対向側壁を有
し、前記対向側壁には、前記キャビティの内方向に突出
する段部が設けられていることを特徴とする。According to the first aspect of the present invention, there is provided an in-cylinder injection spark ignition internal combustion engine according to the present invention, wherein a cavity formed on a piston top surface, a spark plug facing the cavity, A fuel injection valve for injecting fuel into the cavity, wherein the cavity has an opposing side wall facing the fuel injection valve for guiding the fuel vaporized in the cavity to the vicinity of the ignition plug. In addition, the opposing side wall is provided with a stepped portion projecting inward of the cavity.

【０００７】また、本発明による請求項２に記載の筒内
噴射式火花点火内燃機関は、請求項１に記載の筒内噴射
式火花点火内燃機関において、前記段部の突出長さは、
約２ｍｍであることを特徴とする。According to a second aspect of the present invention, there is provided an in-cylinder injection spark ignition internal combustion engine according to the first aspect, wherein the step length of the stepped portion is:
It is about 2 mm.

【０００８】[0008]

【発明の実施の形態】図１は本発明による筒内噴射式火
花点火内燃機関の第一実施形態を示す概略縦断面図であ
り、図２は図１におけるピストンの平面図である。こら
れの図において、１は吸気ポート、２は排気ポートであ
る。吸気ポート１は吸気弁３を介して、排気ポート２は
排気弁４を介して、それぞれ気筒内へ通じている。５は
ピストンであり、６は気筒略中心上部に配置された点火
プラグである。燃料噴射弁７は、気筒上部の吸気ポート
２側に配置され、燃料を比較的厚さの薄い平らな扇状に
噴射するものである。FIG. 1 is a schematic longitudinal sectional view showing a first embodiment of a direct injection type spark ignition internal combustion engine according to the present invention, and FIG. 2 is a plan view of a piston in FIG. In these figures, 1 is an intake port, and 2 is an exhaust port. The intake port 1 communicates through the intake valve 3 and the exhaust port 2 communicates through the exhaust valve 4 into the cylinder. Reference numeral 5 denotes a piston, and reference numeral 6 denotes a spark plug disposed substantially above the center of the cylinder. The fuel injection valve 7 is arranged on the intake port 2 side above the cylinder, and injects the fuel in a relatively thin flat fan shape.

【０００９】燃料噴射弁７は、例えば、高い機関出力が
必要な均一燃焼領域において、吸気行程で必要燃料量を
噴射し、点火時点で気筒内に均一混合気を形成するよう
になっている。一方、成層燃焼領域においては、圧縮行
程後半に必要燃料量を噴射するようになっている。ピス
トン５の頂面には凹状のキャビティ８が形成され、この
キャビティ８は、底壁８ａと、圧縮行程後半で燃料噴射
弁に対向する対向側壁８ｂとを有し、気筒略中心上部に
位置する点火プラグ６がキャビティ８の周囲部に臨むよ
うに、吸気ポート２側に延在している。図１に示すよう
に、キャビティ８の底壁８ａと対向側壁８ｂとは垂直断
面において円弧形状等によって滑らかに接続されてい
る。また、図２に示すように、対向側壁８ｂは、平面視
における水平円弧形状を有し、対向側壁８ｂの高さ中央
における水平円弧半径は約４０ｍｍであるが、上部ほど
水平円弧半径が徐々に小さくされている。また、平面視
において、燃料噴射弁７の噴孔中心と、キャビティ８の
円弧半径中心と、点火プラグ６の中心とは、略一直線上
に位置している。The fuel injection valve 7 injects a required amount of fuel in an intake stroke, for example, in a uniform combustion region where a high engine output is required, and forms a uniform mixture in a cylinder at the time of ignition. On the other hand, in the stratified combustion region, the required fuel amount is injected in the latter half of the compression stroke. A concave cavity 8 is formed on the top surface of the piston 5, and the cavity 8 has a bottom wall 8 a and an opposing side wall 8 b facing the fuel injection valve in the latter half of the compression stroke, and is located substantially above the center of the cylinder. The ignition plug 6 extends toward the intake port 2 so as to face the periphery of the cavity 8. As shown in FIG. 1, the bottom wall 8a and the opposing side wall 8b of the cavity 8 are smoothly connected by an arc shape or the like in a vertical cross section. As shown in FIG. 2, the opposing side wall 8b has a horizontal arc shape in a plan view, and the horizontal arc radius at the center of the height of the opposing side wall 8b is about 40 mm. Has been made smaller. Further, in plan view, the center of the injection hole of the fuel injection valve 7, the center of the arc radius of the cavity 8, and the center of the spark plug 6 are located substantially on a straight line.

【００１０】圧縮行程後半で噴射された燃料は、全て、
図１に示すように、ピストン５の頂面に形成されたキャ
ビティ８内へ進入し、キャビティ８の底壁８ａに衝突し
た後に、底壁８ａに沿って、キャビティ８の対向側壁８
ｂの方向に進行する。燃料噴射弁７から噴射された燃料
は、比較的厚さの薄い平らな扇状であるために、図２に
示すように、キャビティ８の底壁８ａ上を進行する際に
幅方向に広がり、その後、幅方向に広がった燃料各部
は、対向側壁８ｂ上を進行する際に、対向側壁８ｂの水
平円弧形状によって上方向と共に燃料幅中心方向の速度
成分が付与される。また、対向側壁８ｂにおいて、上部
ほど水平円弧半径が小さくされているために、対向側壁
８ｂは滑らかにキャビティ８の内方向へ傾斜しており、
それによって、対向側壁８上を進行する燃料各部は、キ
ャビティ８の周囲部に臨む点火プラグ６近傍に向けられ
る。The fuel injected in the latter half of the compression stroke is
As shown in FIG. 1, after entering into the cavity 8 formed on the top surface of the piston 5 and colliding with the bottom wall 8a of the cavity 8, the opposing side wall 8 of the cavity 8 is moved along the bottom wall 8a.
Proceed in the direction of b. Since the fuel injected from the fuel injection valve 7 has a relatively thin and flat fan shape, it spreads in the width direction when traveling on the bottom wall 8a of the cavity 8, as shown in FIG. When each part of the fuel spread in the width direction advances on the opposing side wall 8b, a velocity component in the fuel width center direction is given together with the upward direction by the horizontal arc shape of the opposing side wall 8b. Further, in the opposing side wall 8b, since the horizontal arc radius is reduced toward the upper part, the opposing side wall 8b is smoothly inclined inward of the cavity 8,
Thereby, each part of the fuel traveling on the opposing side wall 8 is directed to the vicinity of the spark plug 6 facing the periphery of the cavity 8.

【００１１】こうして、燃料噴射弁７から噴射された液
状燃料は、キャビティ８の底壁８ａ及び対向側壁８ｂ上
を進行する際に、キャビティ８の広範囲の壁面から熱吸
収するために良好に気化し、点火時点において、点火プ
ラグ６近傍に着火性の良好な可燃混合気が形成される。
このように、比較的厚さの薄い平らな扇状に燃料を噴射
することで、一般的な円錐状の燃料噴霧に比較して、燃
料を良好に気化させることができるために、燃料噴射終
了を遅らせて比較的多量の燃料噴射が可能となり、低燃
料消費率の成層燃焼領域を高負荷側に拡大することがで
きる。In this way, the liquid fuel injected from the fuel injection valve 7 is well vaporized because it absorbs heat from the wide wall surface of the cavity 8 when traveling on the bottom wall 8a and the opposing side wall 8b of the cavity 8. At the time of ignition, a combustible mixture having good ignitability is formed near the ignition plug 6.
By injecting the fuel in a flat fan shape having a relatively small thickness in this way, the fuel can be better vaporized as compared with a general cone-shaped fuel spray, so that the fuel injection is terminated. A relatively large amount of fuel can be injected with a delay, and the stratified combustion region with a low fuel consumption rate can be expanded to a high load side.

【００１２】しかしながら、成層燃焼領域において、機
関負荷が増大して燃料噴射量が比較的多くなった直後に
は、直前の燃焼における燃料噴射量が少なくてピストン
温度が比較的低いために、噴射された燃料全てをキャビ
ティ８の壁面によって気化させることができない場合が
ある。この場合に備えて、本実施形態では、キャビティ
８の対向側壁８ｂの拡大縦断面図である図３に最も良く
示すように、対向側壁８ｂの最上部に、キャビティ８の
内方向に突出する段部８ｃが設けられている。However, in the stratified combustion region, immediately after the engine load increases and the fuel injection amount becomes relatively large, the fuel injection amount in the immediately preceding combustion is small and the piston temperature is relatively low. In some cases, the entire fuel cannot be vaporized by the wall surface of the cavity 8. In preparation for this case, in the present embodiment, as shown best in FIG. 3, which is an enlarged longitudinal sectional view of the opposing side wall 8b of the cavity 8, a step projecting inward of the cavity 8 is provided at the top of the opposing side wall 8b. A portion 8c is provided.

【００１３】それにより、もし、噴射された燃料の一部
が液状燃料として、対向側壁８ｂ上を進行する場合に
は、この液状燃料は、段部８ｃとの衝突によって微粒化
させられて図３に矢印で示すように、段部８ｃによって
キャビティ８の内方向に偏向させられ、点火プラグ６近
傍へ向かうことはない。こうして、液状燃料が点火プラ
グ６の点火ギャップに付着して失火が発生することは防
止される。また、段部８ｃとの衝突によって微粒化させ
られた液状燃料は、その後の燃焼に際してキャビティ８
内で比較的良好に燃焼し、未燃燃料として排出されるこ
とはない。Accordingly, if a part of the injected fuel travels on the opposing side wall 8b as liquid fuel, the liquid fuel is atomized by collision with the stepped portion 8c, and as shown in FIG. As shown by the arrow in FIG. 7, the light is deflected inward of the cavity 8 by the step 8 c and does not go to the vicinity of the ignition plug 6. In this way, the occurrence of misfire due to the liquid fuel adhering to the ignition gap of the ignition plug 6 is prevented. Further, the liquid fuel atomized by the collision with the step portion 8c is supplied to the cavity 8 during the subsequent combustion.
The fuel burns relatively well within, and is not discharged as unburned fuel.

【００１４】段部８ｃの突出長さは２ｍｍ程度が好まし
い。この程度であれば、キャビティ８の対向側壁８ｂに
沿って点火プラグ６近傍へ向かう気化燃料は、段部８ｃ
を容易に乗り越え、段部８ｃによって点火プラグ６近傍
以外へ偏向させられることはない。The projecting length of the step 8c is preferably about 2 mm. At this level, the vaporized fuel traveling toward the vicinity of the spark plug 6 along the opposing side wall 8b of the cavity 8 will be stepped 8c.
Is not easily deflected to a position other than the vicinity of the ignition plug 6 by the step portion 8c.

【００１５】本実施形態において、図２に示すように、
段部８ｃは、対向側壁８ｂの最上部に全体的に設けられ
ている。それにより、対向側壁８ｂ上を進行しても気化
できなかった最小限の液状燃料を、前述のように点火プ
ラグ６近傍へ向かわせないようにしている。しかしなが
ら、これは、本発明を限定するものではなく、対向側壁
８ｂのいずれの高さ位置に段部８ｃを設けても、少なく
もキャビティ８の底壁８ａを進行する際に気化できなか
った液状燃料が点火プラグ６近傍へ向かうことを確実に
防止することができる。In the present embodiment, as shown in FIG.
The step 8c is provided entirely on the uppermost part of the opposing side wall 8b. This prevents the minimum amount of liquid fuel that could not be vaporized even when traveling on the opposing side wall 8b from being directed to the vicinity of the ignition plug 6 as described above. However, this is not a limitation of the present invention, and even if the step portion 8c is provided at any height position of the opposed side wall 8b, at least the liquid that cannot be vaporized when advancing through the bottom wall 8a of the cavity 8 is provided. It is possible to reliably prevent the fuel from going to the vicinity of the ignition plug 6.

【００１６】また、本実施形態において、段部８ｃは、
対向側壁８ｂに全体的に設けられている。それにより、
液状燃料が点火プラグ６近傍へ向かうことを確実に防止
することができる。しかしながら、これは、本発明を限
定するものではない。燃料噴射弁７から噴射された燃料
の幅中央部分は、キャビティ８の底壁８ａ及び側壁８ｂ
上を最短距離で進行するために、他の燃料部分に比較し
て気化し難い。それにより、液状燃料として点火プラグ
６近傍に向かう可能性が最も高いのは、この燃料部分で
ある。こうして、対向側壁８ｂの中央部だけに段部８ｃ
を設けるようにしても、液状燃料が点火プラグ６近傍へ
向かうことをほぼ確実に防止することができる。In the present embodiment, the step 8c is
It is provided entirely on the opposing side wall 8b. Thereby,
It is possible to reliably prevent the liquid fuel from going to the vicinity of the ignition plug 6. However, this is not a limitation of the present invention. The center of the width of the fuel injected from the fuel injection valve 7 is the bottom wall 8 a and the side wall 8 b of the cavity 8.
Since it travels on the shortest distance above, it is harder to vaporize than other fuel parts. Thus, it is this fuel portion that is most likely to go to the vicinity of the ignition plug 6 as liquid fuel. Thus, the step 8c is formed only at the center of the opposing side wall 8b.
Is provided, it is possible to almost certainly prevent the liquid fuel from going to the vicinity of the ignition plug 6.

【００１７】また、本実施形態において、段部８ｃは、
対向側壁８ｂに連続的に設けられているが、これも本発
明を限定するものではない。段部８ｃは、突出長さが２
ｍｍ程度であれば、前述したように、気化燃料が対向側
壁８ｂに沿って点火プラグ６近傍へ向かうことを、あま
り妨げることはない。しかしながら、気化燃料が点火プ
ラグ６近傍へ多少向かい難くなることも事実である。こ
の問題を改善するために、段部８ｃを対向側壁８ｂに櫛
歯状に部分的に設けることも可能である。それにより、
図示した実施形態に比較して液状燃料が点火プラグ６近
傍に多少向かい易くなるが、従来に比較して液状燃料が
点火プラグ近傍に向かい難くすることができると共に、
図示した実施形態に比較して気化燃料を点火プラグ６近
傍へ向かい易くすることができる。もちろん、本発明
は、燃料が比較的厚さの薄い平らな扇状に噴射される筒
内噴射式火花点火内燃機関に限定されることはなく、燃
料が円錐形状に噴射される筒内噴射式火花点火内燃機関
にも適用可能である。In the present embodiment, the step 8c is
Although provided continuously on the opposing side wall 8b, this does not limit the present invention. The step 8c has a protrusion length of 2
If it is about mm, as described above, it does not hinder the vaporized fuel from traveling toward the vicinity of the ignition plug 6 along the opposed side wall 8b. However, it is also a fact that the vaporized fuel becomes slightly difficult to approach the vicinity of the spark plug 6. In order to solve this problem, it is also possible to partially provide the step 8c in a comb-like shape on the opposing side wall 8b. Thereby,
Although the liquid fuel is slightly more likely to approach the vicinity of the ignition plug 6 as compared to the illustrated embodiment, the liquid fuel can be less likely to approach the vicinity of the ignition plug as compared with the related art.
The vaporized fuel can be more easily moved to the vicinity of the ignition plug 6 as compared with the illustrated embodiment. Of course, the present invention is not limited to the direct injection type spark ignition internal combustion engine in which the fuel is injected in a flat fan shape having a relatively small thickness, but the direct injection type spark in which the fuel is injected in a conical shape. It is also applicable to an ignition internal combustion engine.

【００１８】[0018]

【発明の効果】このように、本発明による筒内噴射式火
花点火内燃機関によれば、ピストン頂面に形成されたキ
ャビティと、キャビティ内に臨む点火プラグと、キャビ
ティ内へ燃料を噴射することを可能とする燃料噴射弁と
を具備し、キャビティは、キャビティ内で気化した燃料
を点火プラグ近傍へ導くために、燃料噴射弁に対向する
対向側壁を有し、対向側壁には、キャビティの内方向に
突出する段部が設けられている。それにより、もし、噴
射された燃料がキャビティ内で十分に気化せずに、一部
の燃料が液状燃料として対向側壁によって点火プラグ近
傍へ導かれる場合には、この液状燃料は、段部と衝突し
て微粒化させられ、キャビティの内方向に偏向させられ
るために、点火プラグ近傍へ向かい難くなる。こうし
て、液状燃料が点火プラグの点火ギャップに付着して失
火が発生する可能性は低減される。As described above, according to the direct injection type spark ignition internal combustion engine of the present invention, the cavity formed on the top surface of the piston, the spark plug facing the cavity, and the fuel being injected into the cavity. The cavity has an opposing side wall facing the fuel injection valve for guiding the fuel vaporized in the cavity to the vicinity of the spark plug, and the opposing side wall has the inside of the cavity. A step is provided to project in the direction. Therefore, if the injected fuel is not sufficiently vaporized in the cavity and a part of the fuel is guided as a liquid fuel to the vicinity of the ignition plug by the opposite side wall, the liquid fuel collides with the step portion. Then, the particles are atomized and deflected inward of the cavity, so that it is difficult to approach the vicinity of the ignition plug. In this way, the possibility that the liquid fuel adheres to the ignition gap of the spark plug and causes a misfire is reduced.

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

【図１】本発明による筒内噴射式火花点火内燃機関の実
施形態を示す概略縦断面図である。FIG. 1 is a schematic longitudinal sectional view showing an embodiment of a direct injection spark ignition internal combustion engine according to the present invention.

【図２】図１のピストンの平面図である。FIG. 2 is a plan view of the piston of FIG. 1;

【図３】ピストン頂面に形成されたキャビティにおける
対向側壁の拡大縦断面図である。FIG. 3 is an enlarged vertical sectional view of an opposing side wall in a cavity formed on a piston top surface.

【符号の説明】[Explanation of symbols]

５…ピストン ６…点火プラグ ７…燃料噴射弁 ８…キャビティ ８ａ…底壁 ８ｂ…対向側壁 ８ｃ…段部 5 Piston 6 Spark plug 7 Fuel injector 8 Cavity 8a Bottom wall 8b Opposite side wall 8c Step

Claims (2)

【特許請求の範囲】[Claims] 【請求項１】 ピストン頂面に形成されたキャビティ
と、前記キャビティ内に臨む点火プラグと、前記キャビ
ティ内へ燃料を噴射することを可能とする燃料噴射弁と
を具備し、前記キャビティは、前記キャビティ内で気化
した燃料を前記点火プラグ近傍へ導くために、前記燃料
噴射弁に対向する対向側壁を有し、前記対向側壁には、
前記キャビティの内方向に突出する段部が設けられてい
ることを特徴とする筒内噴射式火花点火内燃機関。A cavity formed on a top surface of a piston, a spark plug facing the cavity, and a fuel injection valve capable of injecting fuel into the cavity; In order to guide the fuel vaporized in the cavity to the vicinity of the ignition plug, the fuel injection valve has an opposing side wall facing the fuel injection valve.
An in-cylinder injection spark ignition internal combustion engine, wherein a stepped portion is provided which protrudes inward of the cavity. 【請求項２】 前記段部の突出長さは、約２ｍｍである
ことを特徴とする請求項１に記載の筒内噴射式火花点火
内燃機関。2. The in-cylinder injection spark ignition internal combustion engine according to claim 1, wherein the projecting length of the step portion is about 2 mm.
JP11085938A 1999-03-29 1999-03-29 Cylinder injection type spark ignition internal combustion engine Pending JP2000282870A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11085938A JP2000282870A (en) 1999-03-29 1999-03-29 Cylinder injection type spark ignition internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11085938A JP2000282870A (en) 1999-03-29 1999-03-29 Cylinder injection type spark ignition internal combustion engine

Publications (1)

Publication Number Publication Date
JP2000282870A true JP2000282870A (en) 2000-10-10

Family

ID=13872714

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11085938A Pending JP2000282870A (en) 1999-03-29 1999-03-29 Cylinder injection type spark ignition internal combustion engine

Country Status (1)

Country Link
JP (1) JP2000282870A (en)

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