JPH07122406B2 - Combustion chamber of direct injection diesel engine - Google Patents

Combustion chamber of direct injection diesel engine

Info

Publication number
JPH07122406B2
JPH07122406B2 JP3243133A JP24313391A JPH07122406B2 JP H07122406 B2 JPH07122406 B2 JP H07122406B2 JP 3243133 A JP3243133 A JP 3243133A JP 24313391 A JP24313391 A JP 24313391A JP H07122406 B2 JPH07122406 B2 JP H07122406B2
Authority
JP
Japan
Prior art keywords
combustion chamber
injection
nozzle
spray
flame
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
Application number
JP3243133A
Other languages
Japanese (ja)
Other versions
JPH0586864A (en
Inventor
小森正憲
春藤茂
辻村欽司
Original Assignee
株式会社新燃焼システム研究所
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 株式会社新燃焼システム研究所 filed Critical 株式会社新燃焼システム研究所
Priority to JP3243133A priority Critical patent/JPH07122406B2/en
Publication of JPH0586864A publication Critical patent/JPH0586864A/en
Publication of JPH07122406B2 publication Critical patent/JPH07122406B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0672—Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0645—Details related to the fuel injector or the fuel spray
    • F02B23/0669—Details related to the fuel injector or the fuel spray having multiple fuel spray jets per injector nozzle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
    • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
    • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
    • F02B23/0678—Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets
    • F02B23/0687—Multiple bowls in the piston, e.g. one bowl per fuel spray jet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/14—Direct injection into combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)

Description

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

【０００１】[0001]

【産業上の利用分野】本発明は、スモークおよびＮＯX
の大幅な低減を図るための直接噴射式ディーゼル機関の
燃焼室に関する。BACKGROUND OF THE INVENTION This invention is, smoke and NO X
The present invention relates to a combustion chamber of a direct injection diesel engine for achieving a significant reduction of

【０００２】[0002]

【従来の技術】直接噴射式ディーゼル機関において、現
在広く用いられている低圧噴射の場合、噴霧はノズル近
傍で着火した後、全体が火炎に包まれながら進行し、こ
の時、噴霧は、空気と同時に自己の生成した既燃ガスを
巻き込みながら燃焼するので、噴霧中心部において高温
部、酸素不足部が形成されスモークの生成要因となり、
既燃ガスの巻き込みはマイナス要因として働くと言われ
ている。このためスモークを低減するには、燃料と空気
を迅速に混合する必要があり、スワール、スキッシュ等
により空気利用率を向上する方法が採られているが、こ
れでは着火遅れの間の燃料、空気混合速度も増大するた
め、予混合燃焼の増加により燃焼初期の熱発生率が増大
し、ＮＯX の増大を招くという相反する問題を有してお
り、これがスモークとＮＯX の同時低減を困難にしてい
る。2. Description of the Related Art In the case of low-pressure injection, which is widely used in direct injection type diesel engines, the spray is ignited in the vicinity of the nozzle and then progresses while being surrounded by flames. At the same time, it burns while burning the burned gas generated by itself, so a high temperature part and an oxygen deficient part are formed in the center of the spray, which becomes a cause of smoke generation,
It is said that entrainment of burnt gas acts as a negative factor. Therefore, in order to reduce smoke, it is necessary to mix fuel and air quickly, and methods such as swirl and squish are used to improve the air utilization rate. Since the mixing speed also increases, there is a contradictory problem that the heat generation rate in the early stage of combustion increases due to the increase in premixed combustion, leading to an increase in NO X , which makes it difficult to reduce smoke and NO X simultaneously. ing.

【０００３】上記問題を解決するために、高圧噴射（噴
射圧１０００ｋｇ／ｃｍ2 以上）、小噴孔径ノズル、浅
皿燃焼室および低スワールを組合せる方式が知られてい
る。これを図６により説明すると、１はピストン、２は
ピストンリング、３はシリンダライナー、４はガスケッ
ト、５はシリンダヘッド、６はノズル７を有する燃料噴
射弁を示し、ピストン１の頂部には燃焼室９が形成され
ている。ピストン１が上昇し上死点付近に達したとき、
ノズル７から噴射された燃料の噴霧は、壁面１０近傍で
一気に着火した後、火炎は、燃焼室９中心に向かって膨
張するが、噴射の終了まで中心部は不燃域として残る。
すなわち、噴霧は壁面１０に到達するまで燃焼室９中心
に近い不燃域側で十分に空気を巻き込みながら進行し、
壁面１０側では既燃ガスを導入しながら壁面１０に衝突
する二段の燃焼経路をたどる。高圧噴射の場合、噴射時
期を大幅に遅らせても火がつくため、噴射時期遅延との
組み合わせで、低圧噴射と比較してスモークおよびＮＯ
X の同時低減を図ることができる。In order to solve the above problems, there is known a system in which a high pressure injection (injection pressure of 1000 kg / cm 2 or more), a small injection hole diameter nozzle, a shallow dish combustion chamber and a low swirl are combined. This will be described with reference to FIG. 6. 1 is a piston, 2 is a piston ring, 3 is a cylinder liner, 4 is a gasket, 5 is a cylinder head, and 6 is a fuel injection valve having a nozzle 7. A chamber 9 is formed. When piston 1 rises and reaches near top dead center,
The fuel spray injected from the nozzle 7 is ignited at once in the vicinity of the wall surface 10, and then the flame expands toward the center of the combustion chamber 9, but the center remains as a non-combustible region until the end of injection.
That is, the spray progresses while sufficiently entraining air on the non-combustible region side near the center of the combustion chamber 9 until it reaches the wall surface 10,
On the side of the wall surface 10, the burned gas is introduced and the two-stage combustion path that collides with the wall surface 10 is followed. In the case of high-pressure injection, even if the injection timing is significantly delayed, it will catch fire, so in combination with the injection timing delay, smoke and NO will be compared to low-pressure injection.
It is possible to reduce X simultaneously.

【０００４】[0004]

【発明が解決しようとする課題】しかしながら、高圧噴
射は低圧噴射と比較して、噴霧のエネルギーが大きいた
め、火炎は噴射エネルギーにより燃焼室９の中心に向か
って広がるのが抑制される。従って、噴霧はノズル７側
で常に新気を導入するのでスモークは大幅に低減する
が、着火までの空気の導入量が多く既燃ガスの巻き込み
が少ないため、前述したように壁面で一気に着火し、同
一噴射タイミングで比較するとどうしてもＮＯX の発生
量が多くなるという問題を有している。However, since the high-pressure injection has a larger energy of spray as compared with the low-pressure injection, the flame is suppressed from spreading toward the center of the combustion chamber 9 due to the injection energy. Therefore, since the spray always introduces fresh air on the nozzle 7 side, smoke is greatly reduced, but since the amount of air introduced until ignition is large and the amount of burned gas entrainment is small, the wall surface is ignited at once as described above. However, when compared at the same injection timing, there is a problem that the amount of NO x generated will inevitably increase.

【０００５】その理由としては、 燃焼室が円筒形状であるため、着火後の噴霧への既
燃ガスの導入が少ない。すなわち、図６（Ａ）に示すよ
うに、ＡとＢの火炎は壁面１０で衝突するが、速度ベク
トルが同じであるため、力のバランスが保たれ、衝突に
よりお互いの火炎を乱すことなく、内側に曲げられ、燃
焼室９中心に向かって膨張する。しかし、噴霧の持つエ
ネルギーが火炎の膨張エネルギーより大きいため、図の
ように火炎と噴霧の間には空気層１１ができ、噴射期間
中これが保たれ、この部分からの噴霧への既燃ガスの導
入が起きずらい。The reason is that since the combustion chamber has a cylindrical shape, the amount of burnt gas introduced into the spray after ignition is small. That is, as shown in FIG. 6 (A), the flames A and B collide with each other on the wall surface 10, but since the velocity vectors are the same, the balance of forces is maintained, and the flames do not disturb each other due to the collision. It is bent inward and expands toward the center of the combustion chamber 9. However, since the energy of the spray is larger than the expansion energy of the flame, an air layer 11 is formed between the flame and the spray as shown in the figure, and this is maintained during the injection period, and burned gas from this part to the spray is burned. Installation is hard to happen.

【０００６】 急速な圧力上昇による断熱圧縮により
火炎温度が高い。 ＮＯx 発生原因となる最高温度領域が広い。等のこ
とがあげられる。Flame temperature is high due to adiabatic compression due to rapid pressure rise. The maximum temperature range that causes NO x is wide. And so on.

【０００７】本発明は上記問題を解決するために、第１
に、既燃ガス導入による内部ＥＧＲ作用を活用し、第２
に、高温部の攪乱による平均温度の低下を図るものであ
る。後者について言えば、画像解析を用いた二色法によ
る火炎温度分布測定結果によると、高圧噴射の場合、図
６（Ａ）の下半部に示すように、高温の火炎は、噴霧が
壁面１０に衝突し次々に燃焼するに従って、燃焼室９の
中心に向かって押し出されていく火炎の先端近傍に分布
し、壁面１０に近づくほど温度が低いという不均一な温
度分布となっている［（図中、ＴH、ＴM、ＴL は火炎温
度を示し、ＴH＞ＴM＞ＴL ）：第９回内燃機関合同シン
ポジウム講演論文集「高圧噴射ディーゼル機関の火炎温
度分布の測定」第１２３頁、図４］。したがって、高温
部と低温部をうまく混ぜあわせ、高温部分を少なくする
ことができれば、ＮＯx の発生を抑制することができ
る。In order to solve the above problems, the present invention provides a first
To utilize the internal EGR effect by introducing burnt gas,
Moreover, it is intended to reduce the average temperature due to the disturbance of the high temperature part. Regarding the latter, according to the flame temperature distribution measurement result by the two-color method using image analysis,
As shown in the lower half of 6 (A), the high-temperature flame is distributed near the tip of the flame that is pushed out toward the center of the combustion chamber 9 as the spray collides with the wall surface 10 and burns one after another. , The temperature becomes lower as it gets closer to the wall surface 10 [(T H , T M , T L in the figure represent flame temperatures, T H > T M > T L ): No. 9 Proceedings of the Symposium on Joint Internal Combustion Engines "Measurement of Flame Temperature Distribution of High-Pressure Injection Diesel Engine", page 123, Fig. 4]. Therefore, if the high temperature portion and the low temperature portion can be mixed well and the high temperature portion can be reduced, the generation of NO x can be suppressed.

【０００８】本発明は、上記課題を解決するものであっ
て、燃焼室の構造を従来の単純な浅皿燃焼室より改善す
るだけで、スモーク及びＮＯX を同時にかつ大幅に低減
させることができる直接噴射式ディーゼル機関の燃焼室
を提供することを目的とする。[0008] The present invention has been made to solve the above problems, the structure of the combustion chamber only improve than conventional simple shallow dish combustion chamber, it is possible to simultaneously and significantly reduce the smoke and NO X It is intended to provide a combustion chamber of a direct injection diesel engine.

【０００９】[0009]

【課題を解決するための手段】そのために本発明の直接
噴射式ディーゼル機関の燃焼室は、ピストン１の頂部に
形成された燃焼室９と、シリンダヘッド５に配設された
燃料噴射弁６と、燃料噴射弁６のノズル７に設けられた
複数の噴孔と、ノズル７の各噴孔に対向して燃焼室９の
外周に形成された副燃焼室９ａと、副燃焼室９ａの出口
部に形成された絞り部９ｂと、副燃焼室９ａの中心部に
形成された突起部１ｂとを備え、前記ノズル７の噴孔か
らの燃料噴射方向を前記突起部１ｂの側方にずらしたこ
とを特徴とする。なお、上記構成に付加した番号は、本
発明の理解を容易にするために図面と対比させるための
もので、これにより本発明の構成が何ら限定されるもの
ではない。To this end, the combustion chamber of the direct injection type diesel engine of the present invention has a combustion chamber 9 formed at the top of a piston 1 and a fuel arranged in a cylinder head 5. the injection valve 6, the <br/> plurality provided in the nozzle 7 of the fuel injection valve 6 injection hole and, in the combustion chamber 9 opposite the respective injection holes of the nozzle 7
And auxiliary combustion chamber 9a formed on the outer periphery, and a throttle portion 9b formed at the outlet portion of the auxiliary combustion chamber 9a, the center of the auxiliary combustion chamber 9a
The projection 1b is formed, and the fuel injection direction from the injection hole of the nozzle 7 is shifted to the side of the projection 1b. The number added to the above configuration is the book
Intended to contrast with the drawings in order to facilitate understanding of the invention, thereby configuration of the present invention is not intended to be limited.

【００１０】[0010]

【作用及び発明の効果】本発明においては、例えば図１
に示すように、ピストン１が上昇し上死点付近に達した
とき、ノズル７の各噴孔から噴射された燃料の噴霧は、
突起部１ｂの側方にずれた方向で、副燃焼室９ａの壁面
近傍で着火し、火炎は副燃焼室９ａの壁に沿って渦ａと
なり矢印方向に流れる。このとき、火炎は絞り部９ｂに
沿って噴霧側に曲げられ、噴霧の上流側で噴霧に向かっ
て火炎が膨張するため、既燃ガスの導入が促進される。
また、副燃焼室９ａの壁に沿って火炎が膨張し、噴霧に
よる空気流動に妨げられないので、各副燃焼室９ａでの
火炎の膨張により発生した渦ａが、ピストン下降時も残
留し噴射終了後も存在するため、乱れエネルギーの減衰
が少なく混合が促進される。その結果、高圧噴射による
スモーク低減効果を損なうこと無く、ＮＯx の大幅な低
減が可能となる。In [Action and Effect of the Invention The present invention, for example, FIG. 1
As shown in, when the piston 1 rises and reaches near the top dead center, the spray of fuel injected from each injection hole of the nozzle 7 is
In a direction deviated to the side of the projections 1b, ignited in the vicinity of the wall surface of the auxiliary combustion chamber 9a, the flame flows also eddy a next direction of the arrow along the walls of the auxiliary combustion chamber 9a. At this time, the flame is bent toward the spray along the narrowed portion 9b, and the flame expands toward the spray on the upstream side of the spray, so that the introduction of burned gas is promoted.
In addition, the flame expands along the wall of the auxiliary combustion chamber 9a and becomes a spray.
Since it is not hindered by the air flow due to
The vortex a generated by the expansion of the flame remains even when the piston descends.
The turbulent energy is attenuated because it exists even after the end of retained injection.
Less and promotes mixing. As a result, it is possible to significantly reduce NO x without impairing the smoke reduction effect of the high pressure injection.

【００１１】[0011]

【実施例】以下、本発明の実施例を図面を参照しつつ説
明する。図１は、本発明の直接噴射式ディーゼル機関の
燃焼室の１実施例を示し、図Ａは平面図、図Ｂは図Ａの
Ｘ−Ｘ線に沿って矢印方向に見た断面図、図Ｃは燃焼室
の形状を説明するための図である。Embodiments of the present invention will be described below with reference to the drawings. 1 shows one embodiment of a combustion chamber of a direct injection type diesel engine of the present invention, FIG. A is a plan view, FIG. B is a sectional view taken along the line XX of FIG . C is the combustion chamber
It is a figure for explaining the shape of .

【００１２】１はピストン、２はピストンリング、３は
シリンダライナー、４はガスケット、５はシリンダヘッ
ド、６はノズル７を有する燃料噴射弁、９は燃焼室を示
し、ノズル７には、燃料を噴射する６つの噴孔が設けら
れているが、噴孔の数は限定されるものではない。燃焼
室９は、ノズル７の下部に対向して半径Ｒ2 の底面を有
する円錐台形状の突出部１ａと、突出部１ａの外周にノ
ズル７の噴孔に対向して形成された複数の副燃焼室９ａ
と、副燃焼室９ａの中心部に形成された突起部１ｂとを
備えている。本実施例においては、副燃焼室９ａの形状
は、半径Ｒ2 に距離Ｌを加えた点Ｃを中心とした半径ｒ
の円であり、且つ、ノズル７から副燃焼室９ａの奥部ま
での距離をＲ1 としたとき、Ｒ1 ＞Ｒ2 ＋ｒの関係を満
たし、副燃焼室９ａの出口部には、ノズル７に向かって
絞り部９ｂが形成される。そして、ノズル７の噴孔から
噴射される燃料が突起部１ｂの側方に向かうように設定
する。Reference numeral 1 is a piston, 2 is a piston ring, 3 is a cylinder liner, 4 is a gasket, 5 is a cylinder head, 6 is a fuel injection valve having a nozzle 7, 9 is a combustion chamber, and the nozzle 7 is filled with fuel. Six injection holes are provided for injection, but the number of injection holes is not limited. The combustion chamber 9 has a truncated cone-shaped protrusion 1a having a bottom surface with a radius R 2 facing the lower portion of the nozzle 7, and a plurality of sub- units formed on the outer periphery of the protrusion 1a so as to face the nozzle holes of the nozzle 7. Combustion chamber 9a
And a protrusion 1b formed at the center of the auxiliary combustion chamber 9a . In the present embodiment, the shape of the auxiliary combustion chamber 9a has a radius r centered on a point C obtained by adding the distance L to the radius R 2.
When the distance from the nozzle 7 to the inner part of the auxiliary combustion chamber 9a is R 1 , the relationship of R 1 > R 2 + r is satisfied, and the nozzle 7 is provided at the outlet of the auxiliary combustion chamber 9a. The narrowed portion 9b is formed toward. Then, the fuel injected from the injection hole of the nozzle 7 is set to be directed to the side of the protrusion 1b.

【００１３】上記構成からなる本発明の作用について説
明する。ピストン１が上昇し上死点付近に達したとき、
ノズル７の各噴孔から噴射された燃料の噴霧は、突起部
１ｂの側方にずれた方向で、副燃焼室９ａの壁面近傍で
着火し、火炎は副燃焼室９ａの壁に沿って渦ａとなり矢
印方向に流れる。このとき、火炎は絞り部９ｂに沿って
噴霧側に曲げられ、噴霧の上流側で噴霧に向かって火炎
が膨張するため、既燃ガスの導入が促進される。そし
て、寸法Ｌの大小により噴霧内への既燃ガスの巻き込み
をコントロールすることができる。The operation of the present invention having the above structure will be described. When piston 1 rises and reaches near top dead center,
Spraying of the injected fuel from the injection holes of the nozzle 7, the protrusion
In a direction laterally offset 1b, the ignition in the vicinity of the wall surface of the auxiliary combustion chamber 9a, the flame flows also eddy a next direction of the arrow along the walls of the auxiliary combustion chamber 9a. At this time, the flame is bent toward the spray along the narrowed portion 9b, and the flame expands toward the spray on the upstream side of the spray, so that the introduction of burned gas is promoted. The size of the dimension L can control the entrainment of burnt gas in the spray.

【００１４】上記作用を従来例と比較して説明すると、
従来の高圧噴射では、図６Ａに示すように、噴霧の噴射
方向に逆らって火炎が膨張する。このとき、噴霧の持つ
エネルギーが火炎の膨張エネルギーより大きいため図の
ように火炎と噴霧の間には空気層１１ができ、噴霧中こ
れが保たれ噴霧への既燃ガスの導入が起きずらい。ま
た、高圧噴射、小噴孔径ノズル、浅皿燃焼室および低ス
ワールを組合せる方式においては、従来の低圧噴射と比
較して同一噴射時期ではＮＯx の発生が多いため、噴射
タイミングを遅らせる必要がある。一方、スワールによ
る燃焼室内の乱れエネルギーは、図２に示すように、高
スワールほど大きく、また上死点で最大となりピストン
下降に伴って減衰する。従って、高圧噴射のような低ス
ワール且つ上死点前後で噴射する場合には、スワールに
よる火炎の混合効果は少ない。従来は、図６に示すよう
に、火炎は燃焼室の中心に向かって膨張するが、噴射中
は噴霧による空気流動に妨げられ、火炎による乱れエネ
ルギーが減衰し、噴射終了後は各々の火炎はスワールに
よって大きく流されるだけで、火炎の混合にスワールは
殆ど寄与せず、火炎内の乱れエネルギーは急速に減衰す
る。The above operation will be described in comparison with the conventional example.
In a conventional high-pressure injection, as shown in FIG. 6 A, the flame expands against the direction of injection spray. At this time, since the energy of the spray is larger than the expansion energy of the flame, an air layer 11 is formed between the flame and the spray as shown in the figure, and this is maintained during the spray, and it is difficult to introduce burned gas into the spray. Further, in the method of combining the high-pressure injection, the small injection hole nozzle, the shallow dish combustion chamber and the low swirl, NO x is often generated at the same injection timing as compared with the conventional low-pressure injection, so it is necessary to delay the injection timing. is there. On the other hand, the turbulent energy in the combustion chamber due to the swirl becomes larger as the swirl becomes higher, becomes maximum at the top dead center, and attenuates as the piston descends, as shown in FIG. Therefore, when the injection is performed at a low swirl and before and after the top dead center as in the high pressure injection, the effect of mixing the flame by the swirl is small. Conventionally, as shown in FIG. 6 , the flame expands toward the center of the combustion chamber, but during the injection, it is obstructed by the air flow due to the spray, the turbulent energy due to the flame is attenuated, and each flame is Only swept by the swirl, the swirl contributes little to the mixing of the flame and the turbulent energy in the flame decays rapidly.

【００１５】しかしながら、本発明においては、ノズル
７の各噴孔から噴射された燃料の噴霧は、突起部１ｂの
側方にずれた方向で、副燃焼室９ａの壁面近傍で着火
し、副燃焼室９ａの壁面に沿って火炎が膨張し、噴霧に
よる空気流動に妨げられないので、各副燃焼室９ａでの
火炎の膨張により発生した渦ａが、ピストン下降時も残
留し噴射終了後も存在するため、乱れエネルギーの減衰
が少なく混合が促進される。その結果、高圧噴射による
スモーク低減効果を損なうこと無く、ＮＯx の大幅な低
減が可能である。However, in the present invention, the nozzle
The fuel spray injected from each of the injection holes of No. 7 is
Ignition near the wall surface of the auxiliary combustion chamber 9a in a direction displaced to the side
However, since the flame expands along the wall surface of the sub-combustion chamber 9a and is not hindered by the air flow due to the spray, the vortex a generated by the expansion of the flame in each sub-combustion chamber 9a remains even when the piston descends and is injected. Since it exists after the end, the turbulent energy is less attenuated and the mixing is promoted. As a result, it is possible to significantly reduce NO x without impairing the smoke reduction effect of the high pressure injection.

【００１６】図３は副燃焼室９ａおよび絞り部９ｂの他
の実施例を示し、図Ａおよび図Ｂは絞り部９ｂを平面形
状とし、図Ｃは絞り部９ｂを突起形状としている。FIG. 3 shows another embodiment of the auxiliary combustion chamber 9a and the throttle portion 9b. In FIGS. A and B, the throttle portion 9b has a planar shape, and in FIG. C, the throttle portion 9b has a protruding shape.

【００１７】図４および図５は、本発明の他の実施例を
示している。なお、図１の実施例と同一の構成および作
用については、同一番号を付けて説明を省略する。4 and 5 show another embodiment of the present invention . The same components and operations as those of the embodiment of FIG. 1 are designated by the same reference numerals and the description thereof will be omitted.

【００１８】図４の実施例においては、副燃焼室９ａの
上部にも絞り部９ｃを形成し、燃料噴霧がピストンとシ
リンダヘッドの隙間部にもれることによるスモークの悪
化を防ぐようにしている。なお、図４では、図１の突起
部１ｂを省略している。図５の実施例においては、副燃
焼室９ａの出口に突起部９ｄを形成し、既燃ガスの巻き
込みをさらに促進させるようにしている。In the embodiment of FIG. 4, a throttle portion 9c is also formed in the upper portion of the auxiliary combustion chamber 9a to prevent the smoke from being deteriorated due to the fuel spray leaking into the gap between the piston and the cylinder head. . In addition, in FIG. 4, the protrusion of FIG.
The part 1b is omitted. In the embodiment shown in FIG. 5, a projection 9d is formed at the outlet of the auxiliary combustion chamber 9a to further promote the entrainment of burned gas.

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

【図１】本発明の直接噴射式ディーゼル機関の燃焼室の
１実施例を示し、図Ａは平面図、図Ｂは図ＡのＸ−Ｘ線
に沿って矢印方向に見た断面図、図Ｃは燃焼室の形状を
説明するための図である。 1 shows an embodiment of a combustion chamber of a direct injection type diesel engine of the present invention, FIG. A is a plan view, FIG. B is a sectional view taken along the line XX of FIG . C is the shape of the combustion chamber
It is a figure for explaining.

【図２】乱れエネルギーとクランク角度およびスワール
との関係を示す図である。 FIG. 2 is a diagram showing a relationship between turbulent energy, crank angle, and swirl .

【図３】本発明に係わる副燃焼室の他の実施例を示す平
面図である。 FIG. 3 is a plan view showing another embodiment of the auxiliary combustion chamber according to the present invention .

【図４】本発明の直接噴射式ディーゼル機関の燃焼室の
他の実施例を示し、図Ａは平面図、図Ｂは図ＡのＸ−Ｘ
線に沿って矢印方向に見た断面図である。 4 shows another embodiment of the combustion chamber of the direct injection type diesel engine of the present invention, FIG. A is a plan view, and FIG. B is XX of FIG.
It is sectional drawing seen in the arrow direction along a line .

【図５】本発明の直接噴射式ディーゼル機関の燃焼室の
他の実施例を示す平面図である。 FIG. 5 is a plan view showing another embodiment of the combustion chamber of the direct injection diesel engine of the present invention .

【図６】従来の直接噴射式ディーゼル機関の燃焼室の例
を示し、図Ａは平面図、図Ｂは断面図である。 FIG. 6 shows an example of a combustion chamber of a conventional direct injection diesel engine, FIG. A is a plan view and FIG. B is a sectional view .

【符号の説明】[Explanation of symbols]

１…ピストン、１ｂ…突起部、５…シリンダヘッド、６
…燃料噴射弁 ７…ノズル、９…燃焼室、９ａ…副燃焼室、９ｂ、９ｃ
…絞り部 ９ｄ…突起部1 ... Piston, 1b ... Protrusion, 5 ... Cylinder head, 6
... Fuel injection valve 7 ... Nozzle, 9 ... Combustion chamber, 9a ... Sub-combustion chamber, 9b, 9c
... Throttle section 9d ... Projection section

───────────────────────────────────────────────────── フロントページの続き (72)発明者 辻村欽司 茨城県つくば市苅間2530番地 財団法人 日本自動車研究所内 株式会社 新燃焼シ ステム研究所内 (56)参考文献 実開 昭51−42311（ＪＰ，Ｕ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kinji Tsujimura 2530, Kuma, Tsukuba-shi, Ibaraki Japan Automobile Research Institute Co., Ltd. New Combustion System Research Center Co., Ltd. (56) References 51-42311 (JP, U) )

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】ピストンの頂部に形成された燃焼室と、シ
リンダヘッドに配設された燃料噴射弁と、該燃料噴射弁
のノズルに設けられた複数の噴孔と、前記ノズルの各噴
孔に対向して前記燃焼室の外周に形成された副燃焼室
と、該副燃焼室の出口部に形成された絞り部と、前記副
燃焼室の中心部に形成された突起部とを備え、前記ノズ
ルの噴孔からの燃料噴射方向を前記突起部の側方にずら
したことを特徴とする直接噴射式ディーゼル機関の燃焼
室。1. A combustion chamber formed at the top of a piston, a fuel injection valve provided in a cylinder head, a plurality of injection holes provided in a nozzle of the fuel injection valve, and each injection hole of the nozzle. and auxiliary combustion chamber formed on the outer periphery of the combustion chamber opposite the, a diaphragm portion formed in the outlet portion of the sub combustion chamber, the secondary
A combustion chamber of a direct injection diesel engine, comprising: a protrusion formed in the center of the combustion chamber , wherein the direction of fuel injection from the injection hole of the nozzle is shifted to the side of the protrusion.
JP3243133A 1991-09-24 1991-09-24 Combustion chamber of direct injection diesel engine Expired - Lifetime JPH07122406B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3243133A JPH07122406B2 (en) 1991-09-24 1991-09-24 Combustion chamber of direct injection diesel engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3243133A JPH07122406B2 (en) 1991-09-24 1991-09-24 Combustion chamber of direct injection diesel engine

Publications (2)

Publication Number Publication Date
JPH0586864A JPH0586864A (en) 1993-04-06
JPH07122406B2 true JPH07122406B2 (en) 1995-12-25

Family

ID=17099291

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3243133A Expired - Lifetime JPH07122406B2 (en) 1991-09-24 1991-09-24 Combustion chamber of direct injection diesel engine

Country Status (1)

Country Link
JP (1) JPH07122406B2 (en)

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Publication number Priority date Publication date Assignee Title
US6621725B2 (en) 2000-08-17 2003-09-16 Kabushiki Kaisha Toshiba Semiconductor memory device with floating storage bulk region and method of manufacturing the same
FR2909725B1 (en) * 2006-12-12 2012-01-27 Inst Francais Du Petrole INTERNAL COMBUSTION ENGINE WITH DIRECT FUEL INJECTION WITH A PISTON PROVIDED WITH A BOWL LOADING A TOE, ESPECIALLY A DIESEL ENGINE.
JP4657343B2 (en) * 2008-12-16 2011-03-23 本田技研工業株式会社 Direct fuel injection engine
US8967129B2 (en) 2011-01-26 2015-03-03 Caterpillar Inc. Ducted combustion chamber for direct injection engines and method
US10024221B2 (en) 2013-10-09 2018-07-17 Mitsubishi Heavy Industries Engine & Turbocharger, Ltd. Piston for prechamber-type gas engine and prechamber-type gas engine
JP2015113802A (en) * 2013-12-13 2015-06-22 トヨタ自動車株式会社 Control device of compression ignition type internal combustion engine
US9909549B2 (en) 2014-10-01 2018-03-06 National Technology & Engineering Solutions Of Sandia, Llc Ducted fuel injection
US10161626B2 (en) 2015-07-01 2018-12-25 National Technology & Engineering Solutions Of Sandia, Llc Ducted fuel injection
US10138855B2 (en) 2015-07-01 2018-11-27 National Technology & Engineering Solutions Of Sandia, Llc Ducted fuel injection with ignition assist
US10801395B1 (en) 2016-11-29 2020-10-13 National Technology & Engineering Solutions Of Sandia, Llc Ducted fuel injection

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Also Published As

Publication number Publication date
JPH0586864A (en) 1993-04-06

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