JPS63183267A - Swirl chamber type diesel engine - Google Patents
Swirl chamber type diesel engineInfo
- Publication number
- JPS63183267A JPS63183267A JP1283587A JP1283587A JPS63183267A JP S63183267 A JPS63183267 A JP S63183267A JP 1283587 A JP1283587 A JP 1283587A JP 1283587 A JP1283587 A JP 1283587A JP S63183267 A JPS63183267 A JP S63183267A
- Authority
- JP
- Japan
- Prior art keywords
- needle valve
- nozzle
- hole
- fuel
- nozzle hole
- 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
Links
- 239000000446 fuel Substances 0.000 claims abstract description 71
- 238000002347 injection Methods 0.000 claims abstract description 33
- 239000007924 injection Substances 0.000 claims abstract description 33
- 239000007921 spray Substances 0.000 abstract description 31
- 238000002485 combustion reaction Methods 0.000 description 14
- 238000010586 diagram Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000000203 mixture Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
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
- 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
Landscapes
- Fuel-Injection Apparatus (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は渦流室式ディーゼルエンジンに関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a swirl chamber type diesel engine.
（従来技術）
従来より燃料噴射ノズル、特にスロットルタイプの燃料
噴射ノズルにおいては、燃料の噴霧角か異なるものが多
種製造されているが（例えば噴霧角α＝０°、４°、１
２°、２０’ｅｔｃ）、これらのものは個々についてみ
ればそれぞれその噴霧角は所定の角度に固定されている
。このため、燃料噴射ノズルをエンジンに適用する場合
、エンジン仕様に応じて所定の噴霧角のものを選択して
使用している。(Prior Art) Conventionally, various types of fuel injection nozzles, especially throttle type fuel injection nozzles, have been manufactured with different fuel spray angles (for example, spray angle α=0°, 4°, 1°).
2°, 20', etc.), and the spray angle of each of these is fixed at a predetermined angle. Therefore, when applying a fuel injection nozzle to an engine, one with a predetermined spray angle is selected and used according to the engine specifications.
ところが、特に渦流室式ディーゼルエンジンにおいては
、下記するような理由により、例えば噴霧角０°の燃料
噴射ノズルを適用した場合には、高負荷時において排気
中のＮＯｘ発生量が増大してエミッションが悪化し、逆
に噴霧角２０°の広角の燃料噴射ノズルを適用した場合
には、低負荷時において半失火状態が発生し易くなり燃
焼安定性が悪化するという問題があった。However, especially in swirl chamber diesel engines, for the following reasons, for example, when a fuel injection nozzle with a spray angle of 0° is applied, the amount of NOx generated in the exhaust increases under high load, resulting in lower emissions. On the other hand, when a wide-angle fuel injection nozzle with a spray angle of 20° is used, a half-misfire state tends to occur under low load, resulting in a worsening of combustion stability.
即ち、渦流室式ディーゼルエンジンにおいては、ピスト
ンの上動に伴い全負荷域を通じて渦流室内に強い渦流が
発生している。従って、渦流室内に燃料が噴射されると
この渦流により該燃料と空気のミキシングが促進される
ことになる。That is, in a swirl chamber type diesel engine, a strong vortex is generated in the swirl chamber throughout the entire load range as the piston moves upward. Therefore, when fuel is injected into the swirl chamber, the swirl promotes mixing of the fuel and air.
ところが、低負荷時には燃料の噴射量自体が少なく、こ
のため、例えば噴霧角２０°の広角の燃料噴射ノズルを
適用した場合には、少量の燃料がしかも広い噴霧角をも
って燃焼室内に噴射されるため、渦流によるミキシング
促進作用によって混合気が過度に希薄化され（即ち、渦
流によるミキシング作用が逆に災いし）、着火性の悪化
により半失火状態となり易く、エンジンの燃焼の安定性
が悪化し、特に冷間時の始動直後はより顕著であった。However, when the load is low, the amount of fuel injected is small, and for this reason, if a wide-angle fuel injection nozzle with a 20° spray angle is used, a small amount of fuel is injected into the combustion chamber at a wide spray angle. The mixture is excessively diluted by the mixing promotion effect of the vortex (in other words, the mixing effect of the vortex is adversely affected), and the ignitability deteriorates, making it easy to get into a half-misfire state, which deteriorates the stability of combustion in the engine. It was especially noticeable immediately after starting in a cold state.
一方、高負荷時には燃料の噴射量自体が多いため、例え
ば噴霧角０°の燃料噴射ノズルを適用した場合には、渦
流室内に渦流があるとはいえ、多量の燃料がしかもあま
り広がらずに噴射されるため燃料粒子の微細化が不十分
であり、このため渦流室内における混合気のミキシング
状態が悪化し、特に物理的支配による着火遅れが長くな
る。この結果、着火遅れ後の予混合燃焼の初期に燃焼温
度が急激に上昇し、Ｎｏに発生量が増大し、これにより
エミッションが悪化することになる。On the other hand, when the load is high, the amount of fuel injected is large, so if, for example, a fuel injection nozzle with a spray angle of 0° is applied, even though there is a vortex in the vortex chamber, a large amount of fuel will be injected without spreading much. As a result, the fuel particles are not sufficiently refined, which deteriorates the mixing state of the air-fuel mixture in the swirl chamber, and in particular increases the ignition delay due to physical control. As a result, the combustion temperature rises rapidly at the beginning of premixed combustion after the ignition delay, and the amount of fuel generated increases, thereby deteriorating emissions.
即ち、エンジンの全負荷域を通じて良好な燃焼特性を確
保するためには、燃料噴射ノズルの噴霧角を、低負荷時
には小さく、高負荷時には大きくすることが有効である
といえるが、現在のところこのような観点から噴霧角を
負荷に応じて可変とした燃料噴射ノズルは見られない。In other words, in order to ensure good combustion characteristics throughout the entire load range of the engine, it is effective to make the spray angle of the fuel injection nozzle smaller at low loads and larger at high loads. From this point of view, there are no fuel injection nozzles in which the spray angle is variable depending on the load.
尚、実開昭６０−１９２２７７号公報には、針弁の低リ
フト時（即ち低負荷時）には噴霧角を大きくし、高リフ
ト時（高負荷時）には噴霧角を小さくするという噴霧角
の可変技術が開示されているが、このものは、低負荷時
の渦流が弱い低回転時には混合気のミキシングを良好な
らしめてその着火性を良くする目的から噴霧角を高負荷
時よりも大きくしたものである。In addition, Japanese Utility Model Application No. 60-192277 discloses a spray method in which the spray angle is increased when the needle valve has a low lift (i.e., at low load), and the spray angle is decreased when the needle valve is high lift (at high load). A technique for varying the spray angle has been disclosed, but this method makes the spray angle larger than at high loads in order to improve the mixing of the air-fuel mixture and improve its ignitability at low speeds when the vortex is weak at low loads. This is what I did.
（考案の目的）
本発明は上記従来技術の項で指摘した問題点を解決しよ
うとするもので、渦流室に燃料噴射ノズルを配置した渦
流室式ディーゼルエンジンにおいて、燃料噴射ノズルの
噴霧角をエンジンの低負荷時には小さく高負荷時には大
きく設定することにより、低負荷時における燃焼安定性
と高負荷時におけるエミッション性能とを同時に改善す
ることを目的とするものである。(Purpose of the invention) The present invention is intended to solve the problems pointed out in the above-mentioned section of the prior art. The purpose of this is to simultaneously improve combustion stability at low loads and emission performance at high loads by setting the value to be small at low loads and large at high loads.
（目的を達成するための手段）
本発明は上記の目的を達成するための手段として、ノズ
ルボディに形成した噴孔内に針弁の先端部を該噴孔との
間に所定の環状空隙を形成可能に嵌装して構成される燃
料噴射ノズルを渦流室に設けてなる渦流室式ディーゼル
エンジンにおいて、上記燃料噴射ノズルは、上記ノズル
ボディに形成される噴孔を、直穴状の絞り部と該絞り部
に連続してその外端側に位置ししかも外方に向って拡開
変化するテーパ穴部とで構成する一方、上記針弁の先端
部には直軸部と該直軸部に連続してその外端側に位置し
しかも外方に向って拡径変化するテーパ軸部とを形成し
、上記針弁の低リフト時には上記噴孔の絞り部と上記針
弁の直軸部とにより燃料噴流が案内され、上記針弁の高
リフト時には上記噴孔のテーバ穴部と上記針弁のテーパ
軸部とに′より燃料噴流が案内されるように構成したも
のである。(Means for Achieving the Object) As a means for achieving the above-mentioned object, the present invention provides a predetermined annular gap between the tip of the needle valve and the nozzle hole formed in the nozzle body. In a swirl chamber type diesel engine in which a fuel injection nozzle is provided in a swirl chamber, the fuel injection nozzle is configured such that the fuel injection nozzle is fitted into the nozzle body. and a tapered hole part that is continuous with the constriction part and located on the outer end thereof and widens and changes outward, while the tip of the needle valve has a straight shaft part and the straight shaft part. and a tapered shaft portion that is located continuously on the outer end side and whose diameter increases outwardly, and when the needle valve has a low lift, the constricted portion of the nozzle hole and the straight shaft portion of the needle valve are formed. The fuel jet is guided by the needle valve, and when the needle valve is at a high lift, the fuel jet is guided by the tapered hole portion of the nozzle hole and the tapered shaft portion of the needle valve.
（作 用）
本発明では、上記手段により、
（１） 針弁の低リフト時、即ちエンジンの低負荷時
には燃料噴流がノズルボディの噴孔の絞り部と針弁の直
軸部とに案内されて渦流室内に噴射されるため、その噴
霧角が小さくなり、その結果、渦流の生成にかかわらず
燃料の拡散が適度に抑えられ、渦流室内に着火に最適な
比較的リッチな空燃比の混合気が部分的に形成される、
（２）針弁の高リフト時、即ちエンジンの高負荷時には
、燃料噴流がノズルボディの噴孔のテーパ穴部と針弁の
テーパ軸部とに案内されて渦流室内に噴射されるため、
その噴霧角が大きくなり燃料粒子の微細化が促進され、
その結果、着火遅れが短縮され予混合燃焼の初期におけ
る燃焼温度の上昇が効果的に抑えられる、
等の作用が得られる。(Function) In the present invention, by the above means, (1) When the lift of the needle valve is low, that is, when the load of the engine is low, the fuel jet is guided to the constricted part of the nozzle hole of the nozzle body and the vertical axis part of the needle valve. As a result, the spray angle becomes small, and as a result, fuel diffusion is moderately suppressed despite the generation of swirl, and a mixture with a relatively rich air-fuel ratio that is optimal for ignition is created in the swirl chamber. (2) When the needle valve has a high lift, that is, when the engine is under high load, the fuel jet is guided by the tapered hole of the nozzle hole of the nozzle body and the tapered shaft of the needle valve, creating a vortex flow. Because it is sprayed indoors,
The spray angle increases, promoting the miniaturization of fuel particles,
As a result, the ignition delay is shortened and the rise in combustion temperature at the initial stage of premix combustion is effectively suppressed.
（実施例）
以下、第１図ないし第６図を参照して本発明の好適な実
施例を説明する。(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 1 to 6.
（第１の実施例）
第１図及び第２図には本発明の第１の実施例に係る渦流
室式ディーゼルエンジンに適用される燃料噴射ノズルの
噴口部分が示されており、上記各図において符号１はノ
ズルボディである。このノズルボディの先端部には噴孔
ｌＯが形成されている。この噴孔ｌＯは、傾斜面状のバ
ルブシート１４に連続する直穴状の絞り部１１と、該絞
り部ｌＩの外端部に連続して形成され且つ外方に向って
次第に拡開するテーパ穴部１２とで構成されている。(First Embodiment) FIGS. 1 and 2 show the injection port portion of a fuel injection nozzle applied to a swirl chamber type diesel engine according to a first embodiment of the present invention, and each of the above figures In the drawing, reference numeral 1 indicates a nozzle body. A nozzle hole IO is formed at the tip of this nozzle body. The nozzle hole 1O includes a straight hole-shaped constriction part 11 that is continuous with the inclined valve seat 14, and a taper that is formed continuously at the outer end of the constriction part II and that gradually expands outward. It is composed of a hole portion 12.
また、符号２は針弁であり、この針弁２の先端部には上
記ノズルボディ１のバルブシート１４に対して着座又は
離間するシート部２５が設けられている。また、この針
弁２のシート部２５の先端側には、上記噴孔ｌＯの絞り
部１１内に適宜隙間３１をもって遊嵌合し得るような径
寸法をもつ直軸部２１と、該直軸部２１の外端部に連続
し一旦小径変化した後次第に拡径するテーパ軸部２２と
が形成されている。このテーパ軸部２２の外端部の外形
寸法は上記直軸部２１の径寸法より多少小さく設定され
ている。Further, reference numeral 2 designates a needle valve, and a seat portion 25 is provided at the tip of the needle valve 2 to sit on or be spaced from the valve seat 14 of the nozzle body 1 . Further, on the distal end side of the seat portion 25 of this needle valve 2, there is a straight shaft portion 21 having a diameter dimension such that it can be loosely fitted into the constricted portion 11 of the nozzle hole IO with an appropriate gap 31, and A tapered shaft portion 22 is formed continuous with the outer end of the portion 21 and whose diameter once changes to a small diameter and then gradually increases in diameter. The outer dimension of the outer end of this tapered shaft portion 22 is set to be somewhat smaller than the diameter dimension of the straight shaft portion 21 .
このように構成された噴孔ＩＯ及び針弁２を備えた燃料
噴射ノズルにおいては、針弁２の低リフト時、即ち、エ
ンジンの低負荷時には、第１図に示すように噴孔１０の
絞り部Ｉｆと針弁２の直軸部２１とが対向し両者間に筒
状の隙間３１が形成される。従って、ノズルボディｌの
バルブシート１４と針弁２のシート部２５との間を通っ
て噴孔ｌＯ側に噴き出す燃料噴流は、第１図において矢
印Ｆで示すように上記隙間３１部分において絞り部１１
と直軸部２１とに案内され、はとんど広がることなくし
かも層状の噴霧として渦流室側に噴射される。従って、
渦流室内に渦流が生じているにもかかわらず該渦流室内
には着火に最適な比較的リッチな空燃比の混合気層が部
分的に形成され、特に化学的支配による着火遅れ（燃焼
時の化学変化に伴う着火遅れ）が抑制され、その着火性
が向上することになる。In the fuel injection nozzle having the nozzle hole IO and the needle valve 2 configured in this way, when the lift of the needle valve 2 is low, that is, when the load of the engine is low, the nozzle hole 10 is throttled as shown in FIG. The portion If and the straight shaft portion 21 of the needle valve 2 face each other, and a cylindrical gap 31 is formed therebetween. Therefore, the fuel jet that passes between the valve seat 14 of the nozzle body 1 and the seat part 25 of the needle valve 2 and is ejected toward the nozzle hole 1O side is transmitted to the constriction part at the gap 31, as shown by the arrow F in FIG. 11
and the vertical shaft portion 21, and is injected toward the vortex chamber side as a layered spray without spreading out. Therefore,
Despite the vortex that is generated within the vortex chamber, a mixture layer with a relatively rich air-fuel ratio that is optimal for ignition is partially formed within the vortex chamber. The ignition delay caused by the change is suppressed, and the ignition performance is improved.
尚、第５図には、第１図に示した低リフト時における燃
料噴霧のスケッチ図が示されている。但し、この場合の
運転条件は、噴射ｆｌｑ＝ ７ ｍｍ３／ ｓｔとされ
ている。Incidentally, FIG. 5 shows a sketch diagram of fuel spray at the time of low lift shown in FIG. 1. However, the operating conditions in this case are injection flq=7 mm3/st.
一方、針弁２の高リフト時、即ちエンジンの高負荷時に
は、第２図に示すように針弁２のテーパ軸部２２が噴孔
１０のテーパ穴部１２の上端縁付近まで上昇する。従っ
て、ノズルボディ１のバルブシート１４と針弁２のシー
ト部２５との間を通って噴孔１０側に噴き出す燃料噴流
は、先ず針弁２のテーパ軸部２２に案内されて拡大され
る。このテーパ軸部２２により拡大された燃料噴流のう
ち、径方向外側部分の燃料噴流は、今度はテーパ穴部１
２に案内されて矢印Ｆで示す如く次第に広がりながら層
流状態で噴出する。これに対して、径方向内側部分の燃
料噴流は、針弁２の先端部２ｂの前方部分において乱流
を生ぜしめる。この噴流中心部におけるａ流化に伴ない
上記噴流外周側の層流部分の拡大作用がより一層強めら
れ、その結果、全体として噴霧角の広い燃料噴霧が実現
される。On the other hand, when the needle valve 2 has a high lift, that is, when the engine is under high load, the tapered shaft portion 22 of the needle valve 2 rises to near the upper edge of the tapered hole portion 12 of the nozzle hole 10, as shown in FIG. Therefore, the fuel jet that passes between the valve seat 14 of the nozzle body 1 and the seat portion 25 of the needle valve 2 and is ejected toward the nozzle hole 10 is first guided by the tapered shaft portion 22 of the needle valve 2 and expanded. Of the fuel jets expanded by the tapered shaft portion 22, the fuel jets in the radially outer portion are now transferred to the tapered hole portion 1.
2 and ejects in a laminar flow while gradually expanding as shown by arrow F. On the other hand, the fuel jet flow in the radially inner portion causes turbulence in the front portion of the tip portion 2b of the needle valve 2. As the central part of the jet becomes a-flow, the expansion effect of the laminar part on the outer circumferential side of the jet is further strengthened, and as a result, fuel spray with a wide spray angle is realized as a whole.
このため、噴射燃料の微粒化が促進され物理的支配によ
る着火遅れが短くなり、予混合燃焼初期における燃焼温
度の上昇が効果的に抑制される。Therefore, the atomization of the injected fuel is promoted, the ignition delay due to physical control is shortened, and the rise in combustion temperature at the early stage of premix combustion is effectively suppressed.
従って、燃焼温度が低い分だけＮＯｘの発生が抑制され
、エミッション性能が改善されることとなる。Therefore, the generation of NOx is suppressed to the extent that the combustion temperature is lower, and the emission performance is improved.
尚、第６図には、第２図に示した高リフト時における燃
料噴霧のスケッチ図が示されている。但し、この場合の
運転条件は、燃料噴射量ｑ＝２５ｍｓ＋’／ｓｔとされ
ている。Incidentally, FIG. 6 shows a sketch diagram of fuel spray at the time of high lift shown in FIG. 2. However, the operating condition in this case is that the fuel injection amount q=25ms+'/st.
なお、針弁２の最大リフト時、即ちエンジンの最大負荷
時には、針弁２のテーパ軸部２２が噴孔ＩＯの絞り部１
１まで上昇し、燃料噴流はこの絞り部１１に案内されて
噴出し再び噴霧角が小さくなる。このことにより、燃料
噴流の勢いが強くなり、渦流室全体の空気利用率アップ
が図れ、出力が向上する。Note that when the needle valve 2 is at its maximum lift, that is, at the maximum load of the engine, the tapered shaft portion 22 of the needle valve 2 touches the constricted portion 1 of the injection hole IO.
1, the fuel jet is guided by this constriction part 11 and ejected, and the spray angle becomes small again. This increases the force of the fuel jet, increases the air utilization rate of the entire swirl chamber, and improves output.
（第２実施例）
第３図及び第４図には本発明の第２の実施例に係る渦流
室式ディーゼルエンジンに適用される燃料噴射ノズルの
要部が示されている。この燃料噴射ノズルは上記第１の
実施例の燃料噴射ノズルと基本的に同一構成を有するも
のであり、上記第１の実施例のものとは針弁２のテーパ
軸部２２の先端にさらに前方に向って次第に縮径するヘ
ッド部２３を設けた点のみが異なる。(Second Embodiment) FIGS. 3 and 4 show essential parts of a fuel injection nozzle applied to a swirl chamber type diesel engine according to a second embodiment of the present invention. This fuel injection nozzle has basically the same configuration as the fuel injection nozzle of the first embodiment, and is different from the fuel injection nozzle of the first embodiment described above at the tip of the tapered shaft portion 22 of the needle valve 2 further forward. The only difference is that a head portion 23 is provided whose diameter gradually decreases toward .
この燃料噴射ノズルも上記第１の実施例の燃料噴射ノズ
ルと同様の作用効果が得られるものである。This fuel injection nozzle also provides the same effects as the fuel injection nozzle of the first embodiment.
なお、この実施例のものでは針弁先端部２ｂ下流側での
乱流化作用が弱められることにより、第１実施例のもの
に比して燃料噴霧の到達距離か伸びる点で作用上の相違
点がある。In addition, in this embodiment, the turbulence effect on the downstream side of the needle valve tip 2b is weakened, and the difference in operation is that the reach distance of the fuel spray is extended compared to the first embodiment. There is a point.
また、これらの実施例では、針弁２の最大リフト時に噴
霧角を小さくするようにしたが、噴射ノズルの構造上、
最大リフト時も噴霧角を拡げたままとしてもよい。In addition, in these embodiments, the spray angle was made small when the needle valve 2 was at its maximum lift, but due to the structure of the injection nozzle,
The spray angle may remain expanded even at maximum lift.
（発明の効果）
本発明は、ノズルボディに形成し１こ噴孔内に針弁の先
端部を該噴孔との間に所定の環状空隙を形成可能に嵌装
して構成される燃料噴射ノズルを渦流室に設けてなる渦
流室式ディーゼルエンジンにおいて、上記燃料噴射ノズ
ルは、上記ノズルボディに形成される噴孔を、直穴状の
絞り部と該絞り部に連続してその外端側に位置ししか乙
外方に向って拡開変化するテーパ穴部とで構成する一方
、上記針弁の先端部には直軸部と該直軸部に連続してそ
の外端側に位置ししかも外方に向って拡径変化するテー
パ軸部とを形成し、上記針弁の低リフト時には上記噴孔
の絞り部と上記針弁の直軸部とにより燃料噴流が案内さ
れ、上記針弁の高リフト時には上記噴孔のテーパ穴部と
上記針弁のテーパ軸部とにより燃料噴流が案内されるよ
うに構成したことを特徴とするものである。(Effects of the Invention) The present invention provides a fuel injection system in which the tip of a needle valve is fitted into a nozzle hole formed in a nozzle body so as to form a predetermined annular gap between the nozzle body and the nozzle hole. In a swirl chamber type diesel engine in which a nozzle is provided in a swirl chamber, the fuel injection nozzle has a nozzle hole formed in the nozzle body connected to a straight hole-shaped throttle part and the outer end thereof. On the other hand, the tip of the needle valve has a straight shaft part and a straight shaft part continuous with the straight shaft part and located on the outer end side of the needle valve. In addition, a tapered shaft part whose diameter changes outward is formed, and when the needle valve has a low lift, the fuel jet is guided by the constricted part of the nozzle hole and the vertical shaft part of the needle valve, and the needle valve The present invention is characterized in that the fuel jet is guided by the tapered hole portion of the nozzle hole and the tapered shaft portion of the needle valve at the time of high lift.
従って、本発明の渦流室式ディーゼルエンジンによれば
、
（＋） 針弁の低リフト時、即ちエンジンの低負荷時
には燃料噴流がノズルボディの噴孔の絞り部と針弁の直
軸部とに案内されて渦流室内に噴射されるため、その噴
霧角が小さくなり、その結果、渦流の生成にかかわらず
燃料の拡散が適度に抑えられ、渦流室内に着火に最適な
比較的リッチな空燃比の混合気が部分的に形成され、特
に化学的支配による着火性が改善される、
（２）針弁の高リフト時、即ちエンジンの高負荷時には
、燃料噴流がノズルボディの噴孔のテーパ穴部と針弁の
テーパ軸部とに案内されて渦流室内に噴射されるため、
その噴霧角が大きくなり燃料粒子の微細化が促進され、
その結果、着火遅れの短縮化により予混合燃焼の初期に
おける燃焼温度の上昇が効果的に抑えられ、エミッショ
ン性能（特にＮｏに抑制作用）が向上する、
等の効果が得られる。Therefore, according to the swirl chamber type diesel engine of the present invention, (+) When the lift of the needle valve is low, that is, when the load of the engine is low, the fuel jet flows between the constricted part of the nozzle hole of the nozzle body and the vertical axis part of the needle valve. Since the fuel is guided and injected into the vortex chamber, the spray angle becomes small, and as a result, despite the generation of vortices, fuel diffusion is moderately suppressed, and a relatively rich air-fuel ratio, which is optimal for ignition, is created in the vortex chamber. (2) When the needle valve lift is high, that is, when the engine load is high, the fuel jet flows through the tapered hole of the nozzle hole in the nozzle body. and the tapered shaft of the needle valve and are injected into the vortex chamber.
The spray angle increases, promoting the miniaturization of fuel particles,
As a result, by shortening the ignition delay, the rise in combustion temperature at the initial stage of premix combustion is effectively suppressed, and the emission performance (particularly the suppression effect on No. 2) is improved.
第１図は本発明の第１の実進例に係る渦五室式ディーゼ
ルエンジンに適用される燃料噴射ノズルの要部縦断面図
、第２図は第１図の状態変化図、第３図は本発明の第２
の実施例に係る渦流室式ディーゼルエンジンに適用され
る燃料噴射ノズルの要部縦断面図、第４図は第３図の状
態変化図、第５図は針弁の低リフト時における燃料噴苫
のスケッチ図、第６図は針弁の高リフト時における燃１
！Ｆｔ４１霧のスケッチ図である。
１・・・・・ノズルボディ
２・・・・・針弁
ｌＯ・・・・噴孔
Ｉ Ｉ ・ ・ ・ ・絞り部
【２・・・・テーパ穴部
１４・・・・バルブシート
２１・・・・直軸部
２２・・・・テーパｆ山部
２３・・・・ヘッド部
２５・・・・シート部
１Ｌ
メ
ｂ
ｌ ：ノズルボデイ
４ ２ ：針弁
１０：噴孔
／／：ｌｑ２り部
／２：テーパ穴部
ｌｑ：バルブシート
２／：直軸部
２２：テーバ軸部
２３：ヘッド部
２Ｓ＝シ一ト部
【
第４図FIG. 1 is a longitudinal cross-sectional view of a main part of a fuel injection nozzle applied to a vortex five-chamber diesel engine according to a first practical example of the present invention, FIG. 2 is a state change diagram of FIG. 1, and FIG. is the second aspect of the present invention
FIG. 4 is a longitudinal cross-sectional view of a main part of a fuel injection nozzle applied to a swirl chamber type diesel engine according to an embodiment of the present invention, FIG. 4 is a state change diagram of FIG. 3, and FIG. Figure 6 is a sketch diagram of the fuel 1 during high lift of the needle valve.
! It is a sketch diagram of Ft41 fog. 1...Nozzle body 2...Needle valve lO...Nozzle hole II ・ ・ ・ ・ Throttle part [2... Taper hole part 14... Valve seat 21... ... Straight shaft portion 22 ... Tapered f-ridge portion 23 ... Head portion 25 ... Seat portion 1L Meb l : Nozzle body 4 2 : Needle valve 10 : Nozzle hole // : lq2 ridge part / 2: Tapered hole portion lq: Valve seat 2/: Straight shaft portion 22: Taper shaft portion 23: Head portion 2S = Seat portion [Fig. 4
Claims (1)
該噴孔との間に所定の環状空隙を形成可能に嵌装して構
成される燃料噴射ノズルを渦流室に設けてなる渦流室式
ディーゼルエンジンであって、上記燃料噴射ノズルは、
上記ノズルボディに形成される噴孔を、直穴状の絞り部
と該絞り部に連続してその外端側に位置ししかも外方に
向って拡開変化するテーパ穴部とで構成する一方、上記
針弁の先端部には直軸部と該直軸部に連続してその外端
側に位置ししかも外方に向って拡径変化するテーパ軸部
とを形成し、上記針弁の低リフト時には上記噴孔の絞り
部と上記針弁の直軸部とにより燃料噴流が案内され、上
記針弁の高リフト時には上記噴孔のテーパ穴部と上記針
弁のテーパ軸部とにより燃料噴流が案内されるように構
成されていることを特徴とする渦流室式ディーゼルエン
ジン。1. A vortex chamber type fuel injection nozzle is provided in a vortex chamber, with a fuel injection nozzle configured by fitting the tip of a needle valve into a nozzle hole formed in a nozzle body so as to form a predetermined annular gap between the nozzle hole and the nozzle hole. A diesel engine, wherein the fuel injection nozzle is
The nozzle hole formed in the nozzle body is composed of a straight hole-shaped constriction part and a tapered hole part that is continuous with the constriction part and located on the outer end side of the constriction part and widens and changes outward. The tip of the needle valve is formed with a straight shaft part and a tapered shaft part that is continuous with the straight shaft part and located on the outer end side thereof and whose diameter increases outwardly. When the lift is low, the fuel jet is guided by the throttle part of the nozzle hole and the vertical shaft part of the needle valve, and when the lift of the needle valve is high, the fuel jet is guided by the tapered hole part of the nozzle hole and the tapered shaft part of the needle valve. A swirl chamber type diesel engine characterized by being configured so that a jet flow is guided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1283587A JPS63183267A (en) | 1987-01-21 | 1987-01-21 | Swirl chamber type diesel engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1283587A JPS63183267A (en) | 1987-01-21 | 1987-01-21 | Swirl chamber type diesel engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63183267A true JPS63183267A (en) | 1988-07-28 |
Family
ID=11816431
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1283587A Pending JPS63183267A (en) | 1987-01-21 | 1987-01-21 | Swirl chamber type diesel engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63183267A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5832171B2 (en) * | 1976-06-24 | 1983-07-11 | 旭化成株式会社 | Method for manufacturing porous membrane |
| JPS6019767B2 (en) * | 1979-10-19 | 1985-05-17 | 旭化成株式会社 | Ethylene polymerization method |
| JPS6136125B2 (en) * | 1980-07-25 | 1986-08-16 | Hitachi Seisakusho Kk | |
| JPS6261933B2 (en) * | 1976-10-04 | 1987-12-24 | Polaroid Corp |
-
1987
- 1987-01-21 JP JP1283587A patent/JPS63183267A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5832171B2 (en) * | 1976-06-24 | 1983-07-11 | 旭化成株式会社 | Method for manufacturing porous membrane |
| JPS6261933B2 (en) * | 1976-10-04 | 1987-12-24 | Polaroid Corp | |
| JPS6019767B2 (en) * | 1979-10-19 | 1985-05-17 | 旭化成株式会社 | Ethylene polymerization method |
| JPS6136125B2 (en) * | 1980-07-25 | 1986-08-16 | Hitachi Seisakusho Kk |
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