JP3329170B2 - In-cylinder direct injection internal combustion engine - Google Patents
In-cylinder direct injection internal combustion engineInfo
- Publication number
- JP3329170B2 JP3329170B2 JP01554796A JP1554796A JP3329170B2 JP 3329170 B2 JP3329170 B2 JP 3329170B2 JP 01554796 A JP01554796 A JP 01554796A JP 1554796 A JP1554796 A JP 1554796A JP 3329170 B2 JP3329170 B2 JP 3329170B2
- Authority
- JP
- Japan
- Prior art keywords
- curved surface
- piston crown
- fuel
- concave curved
- internal combustion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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
- F02B23/08—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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combustion Methods Of Internal-Combustion Engines (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、筒内に燃料を直接
噴射し、点火プラグによって火花点火を行う筒内直噴式
内燃機関に関し、詳しくは、ピストンの冠面形状改善に
よる燃焼性向上技術に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-cylinder direct injection type internal combustion engine in which fuel is directly injected into a cylinder and spark ignition is performed by a spark plug. .
【０００２】[0002]
【従来の技術】従来、この種の筒内直噴式内燃機関にお
けるピストン冠面の構造としては、図５に示すようなも
のがある（特開平５−２４００４７号公報参照）。即
ち、このものは、ピストン１の冠面１Ａとシリンダヘッ
ド２下面との間に形成される燃焼室３内における、吸気
ポート７からの吸気の逆タンブル渦流６の発生を助長す
るため、ピストン冠面１Ａの一側（例えば吸気側）部分
に、下に凸の曲面を有した凹所４を形成すると共に、こ
の凹所４からなだらかに***してピストン１の上死点に
おいてシリンダヘッド２下面に近接する***部５を形成
したものである。2. Description of the Related Art Conventionally, as a structure of a piston crown surface in a direct injection type internal combustion engine of this kind, there is one as shown in FIG. 5 (see Japanese Patent Application Laid-Open No. H05-240047). In other words, this increases the generation of the reverse tumble vortex 6 of the intake air from the intake port 7 in the combustion chamber 3 formed between the crown surface 1A of the piston 1 and the lower surface of the cylinder head 2. A concave portion 4 having a downwardly curved surface is formed on one side (for example, the intake side) of the surface 1A, and the concave portion 4 is gently raised from the concave portion 4 and the lower surface of the cylinder head 2 at the top dead center of the piston 1. Is formed with a protruding portion 5 close to.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、このよ
うな従来の筒内直噴式内燃機関におけるピストン冠面１
Ａの構造にあっては、ピストン冠面１Ａの一側（例えば
吸気側）部分に下に凸の曲面を有した凹所４を形成して
あるが、他側（例えば排気側）部分、即ち、***部５を
境とした凹所４と反対側のピストン冠面１Ａは平坦であ
るため、この平坦面に燃料が当たった場合には、燃料の
付着が生じ易く、又、上死点付近においては、逆タンブ
ル渦流６を含む筒内ガス流動が弱まり易く、この結果、
上記のように付着した燃料の気化性が悪い。However, in such a conventional in-cylinder direct injection type internal combustion engine, the piston crown 1
In the structure A, the recess 4 having a downwardly curved surface is formed on one side (for example, the intake side) of the piston crown surface 1A, but is formed on the other side (for example, the exhaust side), that is, Since the piston crown surface 1A on the opposite side of the recess 4 from the raised portion 5 is flat, when the fuel hits this flat surface, the fuel is liable to be attached and the vicinity of the top dead center. In the above, the gas flow in the cylinder including the reverse tumble vortex 6 is easily weakened, and as a result,
Poor vaporization of the fuel attached as described above.
【０００４】更に、***部５が形成された部分のピスト
ン冠面１Ａが平坦であるがため、***部５とシリンダヘ
ッド２下面との間に吸入空気が存在する空間が小さくな
り、この部位でのすすや未燃燃料の排出量が増加し、機
関出力の低下を生じる可能性が比較的大きい。そこで、
本発明は以上のような従来の問題点に鑑み、筒内直噴式
内燃機関におけるピストン冠面形状の改善により、燃料
の気化性の向上並びに機関出力の向上を図ることを課題
とする。Further, since the piston crown surface 1A in the portion where the raised portion 5 is formed is flat, the space where the intake air exists between the raised portion 5 and the lower surface of the cylinder head 2 is reduced. There is a relatively high possibility that soot and unburned fuel emission will increase and the engine output will decrease. Therefore,
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and has as its object to improve fuel vaporization and engine output by improving the shape of a piston crown in an in-cylinder direct injection internal combustion engine.
【０００５】[0005]
【課題を解決するための手段】このため、請求項１に係
る発明は、ピストン冠面とシリンダヘッド下面との間に
形成された燃焼室の吸気側壁面に配設された燃料噴射弁
により燃焼室内に燃料を直接噴射し、燃焼室のピストン
冠面と対向する壁面の略中心部に配設された点火プラグ
によって火花点火を行う筒内直噴式内燃機関において、
ピストン冠面の吸気側部分と排気側部分に、相互の交線
が吸気側と排気側とを結ぶ線と略直交する線に沿う方向
に延びかつピストン上死点において前記点火プラグ近辺
に位置するような円筒面状の凹曲面を夫々形成し、前記
交線を稜線とする略山状に***する***部を前記両凹曲
面によってピストン冠面に形成し、 ピストン冠面の排気
側部分に形成された前記凹曲面により、該凹曲面上に生
起したタンブル渦流を圧縮行程中に保持するようにし
た。For this reason, the invention according to claim 1 is characterized in that a fuel is injected by a fuel injection valve disposed on an intake side wall surface of a combustion chamber formed between a piston crown surface and a cylinder head lower surface. In a direct injection type internal combustion engine in which fuel is directly injected into a chamber and spark ignition is performed by a spark plug arranged at a substantially central portion of a wall facing a piston crown of a combustion chamber,
In the intake-side portion and the exhaust-side portion of the piston crown surface, the intersection line extends in a direction along a line substantially orthogonal to the line connecting the intake side and the exhaust side, and is located near the ignition plug at the piston top dead center. Each of the cylindrical concave curved surfaces is formed, and a substantially mountain-shaped raised portion having the intersection line as a ridge line is formed on the piston crown by the biconcave curved surface.
Due to the concave surface formed on the side portion,
The generated tumble vortex during the compression stroke.
Was .
【０００６】かかる請求項１に係る発明において、燃料
は、燃料噴射弁から、ピストン冠面の吸気側に形成され
た凹曲面に向かって噴射される。この際、燃焼室内に噴
射された燃料噴霧は、噴霧自身の噴霧角度の幅並びに燃
焼室内ガス流動による燃料の拡散によって吸気側凹曲面
の形成領域を越えて、ピストン冠面の排気側に形成され
た凹曲面まで回り込む。或いは、燃料噴霧の一部は、直
接排気側凹曲面に到達する。In the invention according to the first aspect, the fuel is injected from the fuel injection valve toward a concave curved surface formed on the intake side of the piston crown surface. At this time, the fuel spray injected into the combustion chamber is formed on the exhaust side of the piston crown surface beyond the formation region of the intake side concave curved surface due to the width of the spray angle of the spray itself and the diffusion of the fuel due to the gas flow in the combustion chamber. Wrap around to the concave surface. Alternatively, part of the fuel spray directly reaches the concave curved surface on the exhaust side.
【０００７】この場合、排気側凹曲面において生起した
タンブル渦流は、排気側凹曲面があるがゆえ、圧縮行程
においても比較的長い時間保持されることになり、燃料
の気化が促進され、混合気の均質化が促進される。又、
排気側部分にも、凹曲面が形成されているため、燃料噴
霧がこれ自身の貫徹力及び燃焼室内ガス流動によって流
されてくる排気側において、比較的大きな空間部が形成
されることになり、燃料が燃焼する際にも、ピストン冠
面に付着している燃料が酸素不足による不完全燃焼を起
こし難くなるため、すす発生や未燃燃料発生の増大が抑
制される。[0007] In this case, the tumble vortex generated on the concave curved surface on the exhaust side is retained for a relatively long time even in the compression stroke due to the concave curved surface on the exhaust side. Is promoted. or,
Since a concave curved surface is also formed on the exhaust side portion, a relatively large space portion is formed on the exhaust side where the fuel spray flows by its own penetration force and gas flow in the combustion chamber, Even when the fuel burns, the fuel adhering to the piston crown surface is unlikely to cause incomplete combustion due to lack of oxygen, so that an increase in soot generation and unburned fuel generation is suppressed.
【０００８】更に、ピストン冠面が概ね凹曲面により形
成され、平坦面が少なくなるため、ピストン冠面の広範
囲にわたってタンブル渦流が保持され、これによる燃料
の巻き上げ効果が充分に得られ、燃料の燃焼室内への均
一的拡散が促進される。請求項２に係る発明は、前記円
筒面状の凹曲面に代えて、球面状の凹曲面とした。Further, since the piston crown surface is formed by a substantially concave curved surface and the flat surface is reduced, the tumble vortex is maintained over a wide range of the piston crown surface, whereby the fuel winding effect is sufficiently obtained, and the fuel combustion is performed. Uniform diffusion into the room is promoted. In the invention according to claim 2, a spherical concave curved surface is used instead of the cylindrical concave curved surface.
【０００９】かかる請求項２に係る発明においては、凹
曲面を球面状に形成してあるため、燃料噴霧の吸気側と
排気側とを結ぶ線と略直交する線に沿う方向への拡がり
が抑制され、混合気がピストン冠面の中央部に寄るた
め、燃料のピストン冠面への付着量がより低減される。
請求項３に係る発明は、前記円筒面状の凹曲面に代え
て、略ピストン軸方向に偏平な円盤面状の凹曲面とし
た。According to the second aspect of the present invention, since the concave curved surface is formed in a spherical shape, the fuel spray is prevented from spreading in a direction along a line substantially perpendicular to a line connecting the intake side and the exhaust side. As a result, the air-fuel mixture approaches the center of the piston crown, so that the amount of fuel adhering to the piston crown is further reduced.
According to a third aspect of the present invention, instead of the cylindrical concave surface, a disk-shaped concave surface that is substantially flat in the axial direction of the piston is provided.
【００１０】かかる請求項３に係る発明においては、凹
曲面を円盤面状に形成してあるため、燃料噴霧の吸気側
と排気側とを結ぶ線と略直交する線に沿う方向への拡が
りが抑制され、混合気がピストン冠面の中央部に寄るた
め、燃料のピストン冠面への付着量がより低減されると
共に、ピストン冠面の周辺部の平面部分を排除できるこ
とによって、ピストン冠面の広範囲にわたってタンブル
渦流が保持され、これによる燃料の巻き上げ効果が充分
に得られるため、燃料の燃焼室内への均一的拡散が促進
される。In the third aspect of the present invention, since the concave curved surface is formed in a disk shape, the fuel spray spreads in a direction along a line substantially orthogonal to a line connecting the intake side and the exhaust side. The amount of fuel adhering to the piston crown surface is further reduced because the air-fuel mixture leans toward the center of the piston crown surface, and the flat portion of the periphery of the piston crown surface can be eliminated. The tumble swirl is maintained over a wide range, and a sufficient effect of raising the fuel is obtained, so that uniform diffusion of the fuel into the combustion chamber is promoted.
【００１１】請求項４に係る発明は、ピストン冠面とシ
リンダヘッド下面との間に形成された燃焼室の吸気側壁
面に配設された燃料噴射弁により燃焼室内に燃料を直接
噴射し、燃焼室のピストン冠面と対向する壁面の略中心
部に配設された点火プラグによって火花点火を行う筒内
直噴式内燃機関において、ピストン冠面の吸気ポートと
対面する部分に、吸気側凹曲面を形成する一方、 ピスト
ン冠面の排気ポートと対面する部分に、タンブル渦流を
生起及び保持する排気側凹曲面を形成し、ピストン冠面
に、前記吸気側凹曲面及び排気側凹曲面相互の交線を稜
線として略山状に***する***部を形成するようにし
た。According to a fourth aspect of the present invention, the piston crown surface and the shell
Intake side wall of combustion chamber formed between the lower surface of the Linda head
Fuel is injected directly into the combustion chamber by a fuel injection valve
Injects, approximately at the center of the wall facing the piston crown of the combustion chamber
In cylinder direct injection internal combustion engine which performs spark ignition by disposed ignition plug part, and the intake port of the piston crown surface
A concave curved surface on the intake side is formed on the facing part, while the piston
A tumble vortex is created at the part of the crown facing the exhaust port.
An exhaust-side concave surface to be generated and held is formed, and an intersection line between the intake-side concave surface and the exhaust-side concave surface is formed on a piston crown surface.
As a line, a raised portion that protrudes in a substantially mountain shape is formed.
【００１２】かかる請求項４に係る発明において、排気
側凹曲面において生起したタンブル渦流は、排気側凹曲
面があるがゆえ、圧縮行程においても比較的長い時間保
持されることになり、燃料の気化が促進され、混合気の
均質化が促進され、排気側部分にも、凹曲面が形成され
ているため、燃料噴霧がこれ自身の貫徹力及び燃焼室内
ガス流動によって流されてくる排気側において、比較的
大きな空間部が形成されることになり、燃料が燃焼する
際にも、ピストン冠面に付着している燃料が酸素不足に
よる不完全燃焼を起こし難くなるため、すす発生や未燃
燃料発生の増大が抑制される。In the fourth aspect of the invention, the tumble vortex generated on the exhaust-side concave curved surface is held for a relatively long time even in the compression stroke because of the presence of the exhaust-side concave curved surface. Is promoted, homogenization of the air-fuel mixture is promoted, and a concave surface is also formed on the exhaust side, so that on the exhaust side where fuel spray flows by its own penetration force and gas flow in the combustion chamber, A relatively large space is formed, and even when the fuel burns, the fuel adhering to the piston crown surface is unlikely to cause incomplete combustion due to lack of oxygen, soot generation and unburned fuel generation Is suppressed.
【００１３】[0013]
【発明の効果】請求項１及び４に係る発明によれば、燃
料の気化が促進され、混合気の均質化が促進されると共
に、燃料が燃焼する際にも、ピストン冠面に付着してい
る燃料が酸素不足による不完全燃焼を起こし難くなるた
め、すす発生や未燃燃料発生の増大を抑制することがで
き、特に、請求項１に係る発明においては、円筒面状の
凹曲面とした結果、ピストン冠面を概ね凹曲面により形
成でき、平坦面を少なくできるため、ピストン冠面の広
範囲にわたってタンブル渦流を保持でき、燃料の燃焼室
内への均一的拡散を促進できる。According to the first and fourth aspects of the present invention, the vaporization of the fuel is promoted, the homogenization of the air-fuel mixture is promoted, and the fuel adheres to the piston crown even when the fuel burns. Incombustible fuel is less likely to be caused by incomplete combustion due to lack of oxygen, so that an increase in soot generation and unburned fuel generation can be suppressed. In particular, in the invention according to claim 1, a cylindrical concave curved surface is used. As a result, the piston crown surface can be formed by a substantially concave curved surface and the flat surface can be reduced, so that the tumble vortex can be maintained over a wide range of the piston crown surface, and uniform diffusion of fuel into the combustion chamber can be promoted.
【００１４】請求項２に係る発明によれば、燃料のピス
トン冠面への付着量をより低減でき、すす発生や未燃燃
料発生の増大をより効果的に抑制することができる。請
求項３に係る発明によれば、燃料のピストン冠面への付
着量をより低減でき、すす発生や未燃燃料発生の増大を
より効果的に抑制することができると共に、燃料の燃焼
室内への均一的拡散がより促進される。According to the second aspect of the present invention, the amount of fuel adhering to the piston crown surface can be further reduced, and the increase in soot generation and unburned fuel generation can be more effectively suppressed. According to the third aspect of the present invention, the amount of fuel adhering to the piston crown surface can be further reduced, soot generation and unburned fuel generation can be more effectively suppressed, and the fuel can enter the combustion chamber. Is further promoted.
【００１５】[0015]
【発明の実施の形態】以下、添付された図面を参照して
本発明を詳述する。図１は、本発明（請求項１及び４に
係る発明）の筒内直噴式内燃機関の一実施形態を示すシ
リンダ構造の断面図であり、ピストン１０の冠面１０Ａ
とシリンダヘッド１１下面との間には燃焼室１２が形成
され、この燃焼室１２の上部のシリンダヘッド１１壁、
即ち、シリンダヘッド１１下部側に形成されたシリンダ
ヘッド燃焼室１２Ａの壁には並列する２つの吸気ポート
１３と並列する２つの排気ポート１４とが設けられ、各
吸気ポート１３には吸気弁１５が、各排気ポート１４に
は排気弁１６が、夫々配設されている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the attached drawings. FIG. 1 is a sectional view of a cylinder structure showing an embodiment of a direct injection type internal combustion engine of the present invention (the invention according to claims 1 and 4).
A combustion chamber 12 is formed between the combustion chamber 12 and the lower surface of the cylinder head 11.
That is, two parallel intake ports 13 and two parallel exhaust ports 14 are provided on the wall of the cylinder head combustion chamber 12 </ b> A formed below the cylinder head 11, and each intake port 13 has an intake valve 15. An exhaust valve 16 is provided at each exhaust port 14.
【００１６】シリンダヘッド１１の吸気ポート１３形成
側壁面の両吸気ポート１３間には、燃料噴射弁１７がピ
ストン冠面１０Ａに対して適切な角度を持つように配設
され、燃焼室１２のピストン冠面１０Ａと対向するシリ
ンダヘッド１１壁面、即ち、シリンダヘッド燃焼室１２
Ａの壁面の略中心部には、点火プラグ１８が配設されて
いる。A fuel injection valve 17 is disposed between the intake ports 13 on the side wall surface of the cylinder head 11 where the intake port 13 is formed so as to have an appropriate angle with respect to the piston crown 10A. The cylinder head 11 wall surface facing the crown surface 10A, that is, the cylinder head combustion chamber 12
A spark plug 18 is disposed substantially at the center of the wall surface of A.
【００１７】ここで、本発明においては、図１及び図２
に示すように、ピストン冠面１０Ａの吸気側部分（吸気
ポート１３と対面する部分）と排気側部分（排気ポート
１４と対面する部分）に、相互の交線が吸気側と排気側
とを結ぶ線と略直交する線に沿う方向に延びかつピスト
ン１０上死点において点火プラグ１８近辺に位置するよ
うな円筒面状の凹曲面１９Ａ，１９Ｂを夫々形成し、前
記交線を稜線２０Ａとする略山状に***する***部２０
を前記両凹曲面１９Ａ，１９Ｂによってピストン冠面１
０Ａに形成するようにしている。Here, in the present invention, FIGS.
As shown in the figure, a crossing line connects the intake side and the exhaust side to the intake side portion (the portion facing the intake port 13) and the exhaust side portion (the portion facing the exhaust port 14) of the piston crown 10A. A cylindrical concave surface 19A, 19B extending in a direction substantially perpendicular to the line and located near the ignition plug 18 at the top dead center of the piston 10 is formed, and the intersection is defined as a ridgeline 20A. Raised portion 20 protruding in mountain shape
Of the piston crown surface 1 by the biconcave curved surfaces 19A and 19B.
0A.
【００１８】次に、かかる構成の作用について説明す
る。燃料は、両吸気ポート１３間に配設された燃料噴射
弁１７から、ピストン冠面１０Ａの吸気側に形成された
凹曲面（以下、吸気側凹曲面）１９Ａに向かって噴射さ
れる。この際、燃焼室１２内に噴射された燃料噴霧は、
噴霧自身の噴霧角度の幅並びに燃焼室１２内ガス流動に
よる燃料の拡散によって吸気側凹曲面１９Ａの形成領域
を越えて、ピストン冠面１０Ａの排気側に形成された凹
曲面（以下、排気側凹曲面）１９Ｂまで回り込む。或い
は、燃料噴霧の一部は、直接排気側凹曲面１９Ｂに到達
する。Next, the operation of the above configuration will be described. The fuel is injected from a fuel injection valve 17 disposed between the intake ports 13 toward a concave curved surface (hereinafter, intake-side concave curved surface) 19A formed on the intake side of the piston crown surface 10A. At this time, the fuel spray injected into the combustion chamber 12
Due to the width of the spray angle of the spray itself and the diffusion of the fuel due to the gas flow in the combustion chamber 12, the concave curved surface formed on the exhaust side of the piston crown surface 10A beyond the region where the intake concave surface 19A is formed (hereinafter referred to as the exhaust concave). (Curved surface) around 19B. Alternatively, a part of the fuel spray directly reaches the exhaust-side concave curved surface 19B.
【００１９】この場合、排気側凹曲面１９Ｂにおいて生
起したタンブル渦流２１は、排気側凹曲面１９Ｂがある
がゆえ、圧縮行程においても比較的長い時間保持される
ことになり、燃料の気化が促進され、混合気の均質化が
促進される。又、排気側部分（排気ポート１４と対面す
る部分）にも、凹曲面１９Ｂが形成されているため、燃
料噴霧がこれ自身の貫徹力及び燃焼室内ガス流動によっ
て流されてくる排気側において、比較的大きな空間部が
形成されることになり、燃料が燃焼する際にも、ピスト
ン冠面１０Ａに付着している燃料が酸素不足による不完
全燃焼を起こし難くなるため、すす発生や未燃燃料発生
の増大を抑制することができる。In this case, the tumble swirl 21 generated on the exhaust-side concave curved surface 19B is retained for a relatively long time even in the compression stroke due to the presence of the exhaust-side concave curved surface 19B, so that fuel vaporization is promoted. Thus, the homogenization of the mixture is promoted. Further, since the concave curved surface 19B is also formed in the exhaust side portion (the portion facing the exhaust port 14), the fuel spray is compared on the exhaust side where the fuel spray flows due to its own penetration force and the gas flow in the combustion chamber. When the fuel burns, the fuel adhering to the piston crown 10A is less likely to undergo incomplete combustion due to lack of oxygen, so that soot or unburned fuel is generated. Increase can be suppressed.
【００２０】特に、この実施形態においては、ピストン
冠面１０Ａを概ね凹曲面により形成でき、平坦面を少な
くできるため、ピストン冠面の広範囲にわたってタンブ
ル渦流を保持でき、これによる燃料の巻き上げ効果が充
分に得られるため、燃料の燃焼室内への均一的拡散を促
進できる。図３は、本発明（請求項２及び４に係る発
明）の筒内直噴式内燃機関の一実施形態を示すピストン
の斜視図であり、この実施形態においては、ピストン冠
面１０Ａの吸気側部分と排気側部分に、図１及び図２の
実施形態の円筒面状の凹曲面１９Ａ，１９Ｂに代えて、
球面状の凹曲面２９Ａ，２９Ｂを形成するようにしたも
のである。In particular, in this embodiment, the piston crown surface 10A can be formed by a substantially concave curved surface and the flat surface can be reduced, so that the tumble vortex flow can be held over a wide range of the piston crown surface, and thereby the fuel winding effect is sufficient. Therefore, uniform diffusion of the fuel into the combustion chamber can be promoted. FIG. 3 is a perspective view of a piston showing one embodiment of a direct injection type internal combustion engine of the present invention (the invention according to claims 2 and 4). In this embodiment, an intake side portion of a piston crown surface 10A is shown. And the exhaust side portion, instead of the cylindrical concave curved surfaces 19A and 19B of the embodiment of FIGS.
The spherical concave surfaces 29A and 29B are formed.
【００２１】かかる実施形態においては、凹曲面２９
Ａ，２９Ｂを球面状に形成してあるため、燃料噴霧の吸
気側と排気側とを結ぶ線と略直交する線に沿う方向への
拡がりを抑制でき、混合気をピストン冠面１０Ａの中央
部に寄せることができるため、燃料のピストン冠面１０
Ａへの付着量をより低減することができる。図４は、本
発明（請求項３及び４に係る発明）の筒内直噴式内燃機
関の一実施形態を示すピストンの斜視図であり、この実
施形態においては、ピストン冠面１０Ａの吸気側部分と
排気側部分に、図１及び図２の実施形態の円筒面状の凹
曲面１９Ａ，１９Ｂに代えて、略ピストン軸方向に偏平
をなす円盤面状の凹曲面３９Ａ，３９Ｂを形成するよう
にしたものである。In this embodiment, the concave surface 29
Since A and 29B are formed in a spherical shape, the fuel spray can be prevented from spreading in a direction along a line substantially perpendicular to the line connecting the intake side and the exhaust side, and the air-fuel mixture is formed in the central portion of the piston crown surface 10A. The fuel piston crown 10
The amount of adhesion to A can be further reduced. FIG. 4 is a perspective view of a piston showing one embodiment of a direct injection internal combustion engine of the present invention (the invention according to claims 3 and 4). In this embodiment, an intake side portion of a piston crown surface 10A is shown. Instead of the cylindrical concave surfaces 19A and 19B of the embodiment of FIGS. 1 and 2 on the exhaust side, disk-shaped concave curved surfaces 39A and 39B which are flat in the substantially piston axial direction are formed. It was done.
【００２２】かかる実施形態においては、凹曲面を円盤
面状に形成してあるため、図３の実施形態と同様に、燃
料噴霧の吸気側と排気側とを結ぶ線と略直交する線に沿
う方向への拡がりを抑制でき、混合気をピストン冠面１
０Ａの中央部に寄せることができるため、燃料のピスト
ン冠面１０Ａへの付着量をより低減することができると
共に、図３の実施形態において存在していたピストン冠
面１０Ａの周辺部の平面部分２９Ｃを排除できることに
よって、ピストン冠面１０Ａの広範囲にわたってタンブ
ル渦流を保持でき、これによる燃料の巻き上げ効果が充
分に得られるため、燃料の燃焼室内への均一的拡散を促
進できる。In this embodiment, since the concave curved surface is formed in the shape of a disk, it follows a line substantially perpendicular to the line connecting the intake side and the exhaust side of the fuel spray, as in the embodiment of FIG. The air-fuel mixture can be prevented from spreading in the
3A, the amount of fuel adhering to the piston crown surface 10A can be further reduced, and the flat portion of the periphery of the piston crown surface 10A existing in the embodiment of FIG. By eliminating 29C, it is possible to maintain the tumble vortex over a wide area of the piston crown surface 10A, and thereby sufficiently obtain the effect of raising the fuel, thereby promoting uniform diffusion of the fuel into the combustion chamber.
【図１】 請求項１及び４記載の発明の一実施形態を示
す断面図FIG. 1 is a sectional view showing an embodiment of the invention described in claims 1 and 4;
【図２】 同上の実施形態におけるピストンの斜視図FIG. 2 is a perspective view of a piston according to the embodiment.
【図３】 請求項２及び４記載の発明の一実施形態を示
すピストンの斜視図FIG. 3 is a perspective view of a piston showing one embodiment of the invention described in claims 2 and 4;
【図４】 請求項３及び４記載の発明の一実施形態を示
すピストンの斜視図FIG. 4 is a perspective view of a piston showing one embodiment of the invention described in claims 3 and 4;
【図５】 従来の筒内直噴式内燃機関のピストン構造を
示す概略図FIG. 5 is a schematic view showing a piston structure of a conventional direct injection type internal combustion engine.
１０ ピストン １０Ａ ピストン冠面 １１ シリンダヘッド １２ 燃焼室 １２Ａ シリンダヘッド燃焼室 １３ 吸気ポート １４ 排気ポート １７ 燃料噴射弁 １８ 点火プラグ １９Ａ，１９Ｂ 凹曲面 ２０ ***部 ２０Ａ 稜線 Reference Signs List 10 piston 10A piston crown 11 cylinder head 12 combustion chamber 12A cylinder head combustion chamber 13 intake port 14 exhaust port 17 fuel injection valve 18 spark plug 19A, 19B concave surface 20 ridge 20A ridge
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平５−171937（ＪＰ，Ａ) 特開 平５−240047（ＪＰ，Ａ) 特開 平５−33650（ＪＰ，Ａ) 特開 平９−14103（ＪＰ，Ａ) 特開 平８−312404（ＪＰ，Ａ) 特開 平９−144543（ＪＰ，Ａ) 特開 平４−183924（ＪＰ，Ａ) 実開 平２−28526（ＪＰ，Ｕ) 特表 平１−500769（ＪＰ，Ａ) 米国特許5642706（ＵＳ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) F02B 23/10 F02B 17/00 F02F 3/26 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-171937 (JP, A) JP-A-5-240047 (JP, A) JP-A-5-33650 (JP, A) 14103 (JP, A) JP-A-8-312404 (JP, A) JP-A-9-144543 (JP, A) JP-A-4-183924 (JP, A) JP-A-2-28526 (JP, U) JP-A-1-500769 (JP, A) US Patent 5,542,706 (US, A) (58) Fields investigated (Int. Cl. 7 , DB name) F02B 23/10 F02B 17/00 F02F 3/26
Claims (4)
に形成された燃焼室の吸気側壁面に配設された燃料噴射
弁により燃焼室内に燃料を直接噴射し、燃焼室のピスト
ン冠面と対向する壁面の略中心部に配設された点火プラ
グによって火花点火を行う筒内直噴式内燃機関におい
て、 ピストン冠面の吸気側部分と排気側部分に、相互の交線
が吸気側と排気側とを結ぶ線と略直交する線に沿う方向
に延びかつピストン上死点において前記点火プラグ近辺
に位置するような円筒面状の凹曲面を夫々形成し、 前記交線を稜線とする略山状に***する***部を前記両
凹曲面によってピストン冠面に形成し、 ピストン冠面の排気側部分に形成された前記凹曲面によ
り、該凹曲面上に生起したタンブル渦流を圧縮行程中に
保持するようにした ことを特徴とする筒内直噴式内燃機
関。1. A fuel injection valve disposed on an intake side wall of a combustion chamber formed between a piston crown and a lower surface of a cylinder head injects fuel directly into the combustion chamber. In an in-cylinder direct-injection internal combustion engine in which spark ignition is performed by a spark plug disposed at a substantially central portion of an opposed wall surface, a crossing line is formed between an intake side and an exhaust side of a piston crown surface. And a cylindrical concave surface which extends in a direction substantially perpendicular to the line connecting the two and which is located near the ignition plug at the piston top dead center. A raised portion is formed on the piston crown by the biconcave curved surface, and is formed by the concave curved surface formed on the exhaust side portion of the piston crown.
During the compression stroke, the tumble vortex generated on the concave surface
An in-cylinder direct injection internal combustion engine characterized in that it is held .
凹曲面としたことを特徴とする請求項１記載の筒内直噴
式内燃機関。2. An in-cylinder direct injection internal combustion engine according to claim 1, wherein said cylindrical concave curved surface is replaced by a spherical concave curved surface.
ン軸方向に偏平な円盤面状の凹曲面としたことを特徴と
する請求項１記載の筒内直噴式内燃機関。3. An in-cylinder direct injection internal combustion engine according to claim 1, wherein said cylindrical concave curved surface is replaced by a disk-shaped concave curved surface which is substantially flat in the axial direction of the piston.
に形成された燃焼室の吸気側壁面に配設された燃料噴射
弁により燃焼室内に燃料を直接噴射し、燃焼室のピスト
ン冠面と対向する壁面の略中心部に配設された点火プラ
グによって火花点火を行う筒内直噴式内燃機関におい
て、ピストン冠面の吸気ポートと対面する部分に、吸気側凹
曲面を形成する一方、 ピストン冠面の排気ポートと対面する部分に、タンブル
渦流を生起及び保持する排気側凹曲面を形成し、 ピストン冠面に、前記吸気側凹曲面及び排気側凹曲面相
互の交線を稜線として略山状に***する***部を形成し
たことを特徴とする筒内直噴式内燃機関。4. Between a piston crown surface and a cylinder head lower surface.
Injection disposed on the intake side wall of the combustion chamber formed at the bottom
The fuel is directly injected into the combustion chamber by the valve, and the combustion chamber is fixed.
Ignition plug located at the approximate center of the wall facing the crown
In- cylinder direct-injection internal combustion engine that performs spark ignition by sparking , the intake-side concave
While forming a curved surface , tumble the part facing the exhaust port on the piston crown.
An exhaust-side concave curved surface for generating and holding a vortex is formed, and the intake-side concave curved surface and the exhaust-side concave curved surface are formed on a piston crown surface.
An in-cylinder direct-injection internal combustion engine characterized by forming a raised portion that protrudes in a substantially mountain-like shape with a line of intersection between them as a ridgeline .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01554796A JP3329170B2 (en) | 1996-01-31 | 1996-01-31 | In-cylinder direct injection internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP01554796A JP3329170B2 (en) | 1996-01-31 | 1996-01-31 | In-cylinder direct injection internal combustion engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09209759A JPH09209759A (en) | 1997-08-12 |
| JP3329170B2 true JP3329170B2 (en) | 2002-09-30 |
Family
ID=11891814
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP01554796A Expired - Lifetime JP3329170B2 (en) | 1996-01-31 | 1996-01-31 | In-cylinder direct injection internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3329170B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4785540B2 (en) * | 2006-01-23 | 2011-10-05 | 日産自動車株式会社 | Internal combustion engine and its piston |
| JP2009191780A (en) * | 2008-02-15 | 2009-08-27 | Nissan Motor Co Ltd | Piston for internal combustion engine and exhaust emission control device of internal combustion engine |
| US9562465B2 (en) | 2014-07-23 | 2017-02-07 | Hyundai Motor Company | Dual pre-chamber piston bowl system |
-
1996
- 1996-01-31 JP JP01554796A patent/JP3329170B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH09209759A (en) | 1997-08-12 |
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