JPH1113594A - Fuel injection nozzle - Google Patents
Fuel injection nozzleInfo
- Publication number
- JPH1113594A JPH1113594A JP9167395A JP16739597A JPH1113594A JP H1113594 A JPH1113594 A JP H1113594A JP 9167395 A JP9167395 A JP 9167395A JP 16739597 A JP16739597 A JP 16739597A JP H1113594 A JPH1113594 A JP H1113594A
- Authority
- JP
- Japan
- Prior art keywords
- combustion chamber
- needle valve
- diameter
- angle
- fuel
- 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.)
- Granted
Links
Classifications
-
- 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
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Combustion Methods Of Internal-Combustion Engines (AREA)
- Exhaust-Gas Circulating Devices (AREA)
- Fuel-Injection Apparatus (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明はディーゼルエンジ
ンの燃料噴射ノズルに関する。The present invention relates to a fuel injection nozzle for a diesel engine.
【０００２】[0002]
【従来の技術】直接噴射式ディーゼルエンジンにおいて
は、図１２のようにピストン２０の頂面に窪状の燃焼室
２５（ピストンキャビティ）を設け、燃料噴射ノズル１
０から燃焼室２５の凹部２２に燃料を噴射するようにし
たものがある（特開昭６３ー１６２９２５号公報）。燃
焼室２５の入口に絞り部２１が形成され、内側の凹部２
２に強い乱流を発生させる。これにより、燃料と空気と
の混合が促進され、スモークの発生量が低減するように
なる。３０は燃料の噴霧を表す。2. Description of the Related Art In a direct injection type diesel engine, a hollow combustion chamber 25 (piston cavity) is provided on the top surface of a piston 20 as shown in FIG.
There is one in which fuel is injected from 0 to the recess 22 of the combustion chamber 25 (Japanese Patent Application Laid-Open No. 63-162925). A throttle 21 is formed at the entrance of the combustion chamber 25, and the inner recess 2 is formed.
2 generates strong turbulence. As a result, mixing of fuel and air is promoted, and the amount of generated smoke is reduced. Numeral 30 denotes fuel spray.
【０００３】[0003]
【発明が解決しようとする課題】ところで、スモークと
ＮＯｘをともに低減するため、高率のＥＧＲ（排気還
流）を行う運転域において、噴射時期を極端に遅延させ
るようにしたものがある（特開平７ー４２８７号公
報）。図１３に燃料噴射角度を，のように広角と狭
角に変えた場合における、高ＥＧＲ条件下の排気性能と
全負荷時の出力性能の実験結果を表す。Incidentally, in order to reduce both smoke and NOx, there is an engine in which the injection timing is extremely delayed in an operation range in which high-rate EGR (exhaust gas recirculation) is performed (Japanese Patent Laid-Open No. HEI 9-209572). No. 7-4287). FIG. 13 shows experimental results of exhaust performance under high EGR conditions and output performance at full load when the fuel injection angle is changed between a wide angle and a narrow angle as shown in FIG.
【０００４】のように噴孔角度が大きい広角ノズル１
０ａにより、燃焼室２５の絞り部２１に噴霧を衝突させ
る場合、高ＥＧＲ条件下においては、燃料の噴射時期が
ピストン上死点以降へ遅延すると、それまで増加傾向を
示したパテキュレートが減少傾向へ転じるようになる。
これは、噴射時期の遅延によって着火遅れ期間が長くな
り、その間に噴霧３０がピストン２０の下降に伴う逆ス
キシュ流によって燃焼室全体へと広がり、予混合燃焼す
る効果と思われる。その反面、着火遅れ期間の短い高速
高負荷域においては、噴射期間が相対的に長くなり、着
火以降に流動の弱い燃焼室２５外に噴射される噴霧が増
加するため、スモークが発生しやすく、全負荷性能は低
下する。A wide-angle nozzle 1 having a large injection hole angle as shown in FIG.
0a, when the spray collides with the throttle portion 21 of the combustion chamber 25, under high EGR conditions, if the fuel injection timing is delayed after the top dead center of the piston, the particulates that have been increasing until then tend to decrease. It turns to.
This seems to be due to the effect that the ignition delay period is prolonged due to the delay of the injection timing, during which the spray 30 spreads over the entire combustion chamber due to the reverse squish flow caused by the lowering of the piston 20, and premix combustion occurs. On the other hand, in the high-speed high-load region where the ignition delay period is short, the injection period is relatively long, and the amount of spray injected outside the combustion chamber 25 having a weak flow after ignition increases, so that smoke is easily generated, Full load performance is reduced.
【０００５】のように噴孔角度が小さい狭角ノズル１
０ｂにより、図１２の従来例と同様に燃焼室２５の絞り
部２１の下側に噴霧を衝突させる場合、高速高負荷域に
おいては、燃焼室２５の絞り部２１によって強い乱流が
凹部２２に発生し、噴霧３０と空気との混合を促進する
ため、スモークの発生量が抑制され、全負荷性能は向上
する。その反面、高ＥＧＲ条件下においては、噴霧３０
が燃焼室２５の凹部２２に保持され、燃焼室２５の外側
への広がりを抑えられるため、予混合化が十分に行われ
ず、噴射時期をピストン上死点以降へ遅延しても、パテ
キュレートの減少傾向は見られない。[0005] A narrow-angle nozzle 1 having a small injection hole angle as described above
When the spray collides with the lower side of the throttle section 21 of the combustion chamber 25 as in the conventional example of FIG. 12, strong turbulent flow is generated by the throttle section 21 of the combustion chamber 25 in the recess 22 in the high-speed and high-load range. Since the mixture is generated and promotes mixing of the spray 30 and the air, the amount of generated smoke is suppressed, and the full load performance is improved. On the other hand, under high EGR conditions, the spray 30
Is held in the concave portion 22 of the combustion chamber 25, and the spread to the outside of the combustion chamber 25 can be suppressed. Therefore, even if the premixing is not sufficiently performed and the injection timing is delayed after the piston top dead center, the No downward trend is seen.
【０００６】この発明はこのような問題点に着目してな
されたものであり、１つの噴射ノズルに広角噴孔と狭角
噴孔を併用することにより、広い運転範囲で予混合燃焼
による排気性能を改善しつつ、高速域での出力性能の向
上を実現しようとするものである。The present invention has been made in view of such a problem, and by using both a wide-angle injection hole and a narrow-angle injection hole for one injection nozzle, the exhaust performance by premixed combustion in a wide operation range. While improving the output performance in the high-speed range.
【０００７】[0007]
【発明が解決しようとする課題】第１の発明では、ピス
トン頂面の燃焼室へ向けて燃料を噴射するディーゼルエ
ンジンにおいて、燃料の噴射量を制御する針弁と、その
リフト量を運転条件に応じて制御する手段と、針弁のリ
フトに伴って燃料を燃焼室に広角をもって噴射する小径
の噴孔と、針弁のリフトに伴って燃料を燃焼室に狭角を
もって噴射する大径の噴孔と、を設ける。According to the first invention, in a diesel engine for injecting fuel toward a combustion chamber on the top surface of a piston, a needle valve for controlling an injection amount of fuel and a lift amount of the needle valve are used as operating conditions. A small-diameter injection hole that injects fuel into the combustion chamber at a wide angle with the needle valve lift, and a large-diameter injection hole that injects fuel into the combustion chamber at a narrow angle with the needle valve lift. And a hole.
【０００８】第２の発明では、第１の発明における前記
大径噴孔は、そのノズル内部への開口部に流量係数を高
める手段を備える。According to a second aspect of the present invention, the large-diameter injection hole according to the first aspect of the present invention is provided with a means for increasing a flow coefficient at an opening portion inside the nozzle.
【０００９】第３の発明では、第１の発明における前記
リフト量制御手段は、針弁のリフト量を低速域で小さ
く、高速域で大きく制御する。In a third aspect, the lift amount control means in the first aspect controls the lift amount of the needle valve to be small in a low speed range and large in a high speed range.
【００１０】第４の発明では、第１の発明において、前
記小径噴孔の位置を大径噴孔の位置に対し、燃料の供給
上流側に配設する。[0010] In a fourth aspect based on the first aspect, the position of the small-diameter injection hole is disposed upstream of the fuel supply with respect to the position of the large-diameter injection hole.
【００１１】第５の発明では、第４の発明における前記
針弁には、針弁低リフト時の小径噴孔と相対する位置に
凹部を形成する。According to a fifth aspect of the present invention, a recess is formed in the needle valve according to the fourth aspect of the present invention at a position facing the small diameter injection hole at the time of low lift of the needle valve.
【００１２】第６の発明では、第１の発明における、前
記ピストン頂面の燃焼室がその開口部に絞り部を備え、
広角の小径噴孔から噴射される噴霧の衝突位置が、ピス
トン上死点位置における燃焼室の絞り部の壁面、狭角の
大径噴孔から噴射される噴霧の衝突位置が、ピストン上
死点位置における燃焼室の絞り部内側の壁面になるよう
にそれぞれ設定する。In a sixth aspect based on the first aspect, the combustion chamber on the top surface of the piston has a throttle portion at an opening thereof.
The collision position of the spray injected from the wide-angle small-diameter injection hole is the piston top dead center, and the collision position of the spray injected from the narrow-angle large-diameter injection hole is the piston top dead center. Each is set so that it becomes the wall surface inside the throttle portion of the combustion chamber at the position.
【００１３】第７の発明では、第１の発明における、前
記ピストン頂面の燃焼室がその最大幅と同幅の開口部を
備え、広角の小径噴孔から噴射される噴霧の衝突位置
が、ピストン上死点位置における燃焼室の上端から内側
下方へ所定距離のを境にその上側の壁面、狭角の大径噴
孔から噴射される噴霧の衝突位置が、同じく所定距離の
位置を境にその下側の壁面になるようにそれぞれ設定す
る。According to a seventh aspect of the present invention, in the first aspect, the combustion chamber at the top of the piston has an opening having the same width as the maximum width thereof, and the collision position of the spray injected from the wide-angle small-diameter injection hole is as follows. A predetermined distance inward and downward from the upper end of the combustion chamber at the top dead center position of the piston, the upper wall surface, and the collision position of the spray injected from the small-diameter large-diameter injection hole also borders on the position of the predetermined distance Each is set so that it becomes the lower wall surface.
【００１４】第８の発明では、第１の発明における前記
リフト量制御手段は、高ＥＧＲ率の運転域で噴射時期を
ピストン上死点以降へ遅延させる場合に針弁のリフト量
を小さく制御する。In an eighth aspect, the lift amount control means in the first aspect controls the lift amount of the needle valve to be small when the injection timing is delayed after the piston top dead center in an operation range of a high EGR rate. .
【００１５】[0015]
【発明の効果】第１の発明において、各噴孔から針弁の
リフトに伴って燃料が噴射する。針弁の低リフト時は、
針弁とそのシート部との隙間面積が小さく、各噴孔の噴
射量は噴孔径の違いにあまり影響されない。針弁の高リ
フト時は、針弁とそのシート部との隙間面積が総噴孔面
積よりも上回るため、各噴孔の噴射量は噴孔径に比例す
るようになる。つまり、広角噴射と狭角噴射の噴射量割
合は、低リフト時にほぼ同等になる一方、高リフト時は
大径側の狭角噴孔の噴射量割合が大きくなる。According to the first aspect of the present invention, fuel is injected from each injection hole with the lift of the needle valve. When the needle valve is low lift,
The clearance area between the needle valve and its seat portion is small, and the injection amount of each injection hole is not so affected by the difference in the injection hole diameter. When the needle valve is at a high lift, the gap area between the needle valve and its seat is larger than the total injection hole area, so that the injection amount of each injection hole is proportional to the injection hole diameter. That is, the injection amount ratio between the wide-angle injection and the narrow-angle injection is almost equal at the time of the low lift, while the injection amount ratio of the large-diameter narrow-angle injection hole becomes large at the time of the high lift.
【００１６】針弁の低リフト時において、スモークの増
加を抑えつつ、ＮＯｘを低減するため、高率のＥＧＲに
より燃焼温度を低下させ、同時に噴射時期をピストン上
死点以降へ遅延させると、広角噴射による予混合燃焼の
効果により、噴射時期の遅延に伴うパティキュレートの
低減効果も確保できる。高速高負荷域では、針弁が高リ
フト状態になり、流動の弱い燃焼室外への広角噴射量の
割合よりも、流動の強い燃焼室への狭角噴射量の割合が
大きくなるため、スモーク性能や出力性能の向上をもた
らす。At the time of low lift of the needle valve, in order to reduce NOx while suppressing an increase in smoke, the combustion temperature is lowered by a high rate of EGR, and at the same time, the injection timing is delayed beyond the piston top dead center. Due to the effect of the premixed combustion by the injection, the effect of reducing particulates due to the delay of the injection timing can also be secured. In the high-speed, high-load range, the needle valve is in a high-lift state, and the ratio of the narrow-angle injection amount to the strong-flow combustion chamber is larger than the ratio of the wide-angle injection amount to the outside of the weakly-flowing combustion chamber. And improve the output performance.
【００１７】第２の発明では、流量係数を高める手段に
より、針弁の高リフト時における、狭角噴射量の割合が
さらに大きくなる。つまり、狭角ノズル単独の場合にス
モーク性能や出力性能を近づけられる。In the second aspect of the present invention, the ratio of the narrow-angle injection amount at the time of high lift of the needle valve is further increased by the means for increasing the flow coefficient. That is, the smoke performance and the output performance can be approximated when the narrow-angle nozzle is used alone.
【００１８】第３の発明では、低速域は針弁が低リフト
状態になり、高率のＥＧＲにより燃焼温度を低下させ、
同時に噴射時期をピストン上死点以降へ遅延させると、
広角噴射による予混合燃焼の効果により、噴射時期の遅
延に伴うパティキュレートの低減効果も確保できる。高
速域は針弁の高リフト状態になり、流動の強い燃焼室内
への狭角噴射量の割合が広角噴射量の割合よりも大きく
なるため、スモーク性能や出力性能の向上をもたらす。In the third aspect of the present invention, the needle valve is in a low lift state in a low speed range, and the combustion temperature is reduced by a high rate of EGR.
At the same time, if the injection timing is delayed after the piston top dead center,
Due to the effect of the premixed combustion by the wide-angle injection, the effect of reducing particulates due to the delay of the injection timing can also be secured. In the high-speed range, the needle valve is in a high-lift state, and the ratio of the narrow-angle injection amount into the combustion chamber where the flow is strong becomes larger than the ratio of the wide-angle injection amount, thereby improving the smoke performance and the output performance.
【００１９】第４の発明では、針弁のリフト時とくにそ
の低リフト時における、燃料の供給上流側に位置する広
角噴孔への流量割合（噴射量割合）が増加し、また第５
の発明では、針弁の低リフト時において、凹部に相対す
る広角噴孔への流量割合（噴射量割合）はさらに大きく
なる。これらにより、広角噴射による予混合燃焼の影響
が強まるため、噴射時期の遅延に伴うパティキュレート
の低減効果を促進できる。According to the fourth aspect of the present invention, when the needle valve is lifted, especially when the needle valve is at a low lift, the flow rate (injection rate) to the wide-angle injection hole located upstream of the fuel supply increases.
According to the invention, when the needle valve is at a low lift, the flow rate ratio (injection amount ratio) to the wide-angle injection hole facing the concave portion is further increased. As a result, the effect of the premixed combustion by the wide-angle injection is increased, so that the effect of reducing particulates due to the delay of the injection timing can be promoted.
【００２０】第６の発明では、針弁の低リフト時におい
て、スモークの増加を抑えつつ、ＮＯｘを低減するた
め、高率のＥＧＲにより燃焼温度を低下させ、同時に噴
射時期をピストン上死点以降へ遅延させると、広角噴射
による予混合燃焼の効果により、噴射時期の遅延に伴う
パティキュレートの低減効果を確保できる。高速高負荷
域においては、針弁が高リフト状態になり、燃焼室の奥
部への狭角の噴射量割合が増えるのと、燃焼室にその絞
り部で強い乱流が発生するのとにより、スモーク性能や
出力性能の向上をもたらす。In the sixth aspect of the present invention, at the time of low lift of the needle valve, the combustion temperature is reduced by a high rate of EGR in order to reduce the NOx while suppressing the increase of the smoke, and at the same time, the injection timing is changed after the piston top dead center. When it is delayed, the effect of the premixed combustion by the wide-angle injection can secure the effect of reducing particulates due to the delay of the injection timing. In the high-speed, high-load region, the needle valve is in a high-lift state, and the ratio of the narrow-angle injection amount to the back of the combustion chamber increases, and strong turbulence is generated in the combustion chamber at the throttle. , Resulting in improved smoke performance and output performance.
【００２１】第７の発明では、絞り部がないため、燃焼
室に強い乱流は生じないが、第６の発明と同様の排気性
能と出力性能が得られる。In the seventh aspect, since there is no throttle, strong turbulence does not occur in the combustion chamber, but the same exhaust performance and output performance as in the sixth aspect can be obtained.
【００２２】第８の発明では、高率のＥＧＲを行う運転
域において、噴射時期をピストン上死点以降へ遅延させ
るにより、スモークの増加を抑えつつ、ＮＯｘを低減で
きる。また、この運転域では、針弁が低リフト状態にな
るため、広角噴射による予混合燃焼の効果により、噴射
時期の遅延に伴うパティキュレートの低減効果も確保で
きる。According to the eighth aspect of the present invention, in an operation range in which high-rate EGR is performed, NOx can be reduced while suppressing an increase in smoke by delaying the injection timing after the piston top dead center. Further, in this operation region, the needle valve is in a low lift state, so that the effect of the premixed combustion by the wide-angle injection can also ensure the effect of reducing particulates due to the delay of the injection timing.
【００２３】[0023]
【発明の実施の形態】図１は燃料噴射ノズルの構成を示
すものであり、ノズルホルダ１の下部にノズル１０ｃが
取り付けられ、ノズル１０ｃの内部に燃料噴射を制御す
る針弁１１が収装される。針弁１１のリフト量を運転条
件に応じて制御するため、第１スプリング２および第２
スプリング３が針弁１１の上部に設けられる。FIG. 1 shows the structure of a fuel injection nozzle. A nozzle 10c is attached to a lower portion of a nozzle holder 1, and a needle valve 11 for controlling fuel injection is housed inside the nozzle 10c. You. In order to control the lift amount of the needle valve 11 according to the operating conditions, the first spring 2 and the second spring
A spring 3 is provided above the needle valve 11.
【００２４】これらスプリング２，３により、針弁１１
はシート部（図２の１４）に着座するように付勢され、
エンジン回転に同期して駆動される燃料噴射ポンプから
燃料が供給されると、針弁１１はその圧力に応じてリフ
トする。The needle valves 11 are formed by the springs 2 and 3.
Is urged to sit on the seat (14 in FIG. 2),
When fuel is supplied from a fuel injection pump driven in synchronization with engine rotation, the needle valve 11 lifts according to the pressure.
【００２５】燃料圧力が低いときは、第１スプリング２
がロッド４およびスペーサ５を介して圧縮され、第１ス
プリング２の撓み量が隙間ｘ１（初段リフト量）になる
と、第２スプリング３の下端にスペーサ５が突き当た
る。When the fuel pressure is low, the first spring 2
Is compressed via the rod 4 and the spacer 5, and when the amount of deflection of the first spring 2 reaches the gap x1 (the amount of first-stage lift), the spacer 5 abuts against the lower end of the second spring 3.
【００２６】燃料圧力が高いときは、針弁１１のリフト
により、第１スプリングに加えて第２スプリング３もス
ペーサ５を介して圧縮される。第１スプリング２および
第２スプリング３の撓み量が全体として隙間ｘ２になる
と、針弁１１の大径段部１１ａがピース７（第２スプリ
ング３とノズル１０ｃとの間に介装される）に突き当た
り、針弁１１のそれ以上のリフトは規制される。したが
って、隙間ｘ２がフルリフト量に相当する。When the fuel pressure is high, the lift of the needle valve 11 causes the second spring 3 as well as the first spring to be compressed via the spacer 5. When the deflection amount of the first spring 2 and the second spring 3 becomes the gap x2 as a whole, the large-diameter step portion 11a of the needle valve 11 is inserted into the piece 7 (interposed between the second spring 3 and the nozzle 10c). At the end, further lift of the needle valve 11 is restricted. Therefore, the gap x2 corresponds to the full lift amount.
【００２７】図２はノズル１０ｃの先端部における、噴
孔の配設状態を表すものであり、燃料を広角αに噴射す
る小径の噴孔１２ａ〜１２ｃと、燃料を狭角βに噴射す
る大径の噴孔１３ａ〜１３ｃと、がそれぞれ円周方向へ
交互に配設される。噴孔１３ａ〜１３ｃの流量係数を高
めるため、これら内側の開口（噴孔への流入口）をなめ
らかな円弧状に広げる面取り部１８が設けられる。FIG. 2 shows the arrangement of the injection holes at the tip of the nozzle 10c. The injection holes 12a to 12c have a small diameter for injecting the fuel at a wide angle α, and the large holes for injecting the fuel at a narrow angle β. The injection holes 13a to 13c having the diameters are alternately arranged in the circumferential direction. In order to increase the flow coefficient of the injection holes 13a to 13c, a chamfered portion 18 for expanding these inner openings (inflow ports to the injection holes) into a smooth arc is provided.
【００２８】これらの噴孔１２ａ〜１２ｃおよび１３ａ
〜１３ｃは、針弁１１がリフトすると、シート部１４と
の隙間を通して供給される燃料を噴射する。燃料噴射時
の針弁１１とそのシート部１４との隙間面積について
は、低リフト時は噴孔１２ａ〜１２ｃと１３ａ〜１３ｃ
の総開口面積を下回り、図３のフルリフト時は噴孔１２
ａ〜１２ｃと１３ａ〜１３ｃの総開口面積を大幅に上回
るように設定される。These injection holes 12a to 12c and 13a
When the needle valve 11 is lifted, the fuel supplies 13 to 13c inject fuel supplied through a gap with the seat portion 14. Regarding the clearance area between the needle valve 11 and its seat portion 14 during fuel injection, the injection holes 12a to 12c and 13a to 13c
In the case of the full lift shown in FIG.
It is set so as to greatly exceed the total opening area of a to 12c and 13a to 13c.
【００２９】図示しないが、ディーゼルエンジンの制御
装置として、エンジンの運転条件に応じてＥＧＲ率を制
御する手段と、針弁が低リフトの高ＥＧＲ条件下におい
て、噴射時期を上死点以降へ遅延させる手段を備える。Although not shown, a control unit for the diesel engine controls the EGR rate in accordance with the operating conditions of the engine, and a delay of the injection timing to after the top dead center under high EGR conditions where the needle valve is at a low lift. And means for causing it to be provided.
【００３０】このような構成に基づく作用を説明する。
図４に各代表点での広角噴射１と狭角噴射２の噴射量割
合の比較を表す。The operation based on such a configuration will be described.
FIG. 4 shows a comparison of the injection amount ratio between the wide-angle injection 1 and the narrow-angle injection 2 at each representative point.
【００３１】針弁１１の低リフト時は、シート部１４と
の隙間面積が小さく、この隙間に各噴孔１２ａ〜１２ｃ
と１３ａ〜１３ｂへの流量は支配されるため、広角噴射
量の割合と狭角噴射量の割合が略同等となるのに対し、
針弁１１のフルリフト時は、大径噴孔１３ａ〜１３ｂの
噴射量割合が小径噴孔１２ａ〜１２ｃの噴射量割合に較
べて大きくなる。When the needle valve 11 is at a low lift, the clearance area between the needle valve 11 and the seat portion 14 is small, and each of the injection holes 12a to 12c
And the flow rates to 13a to 13b are controlled, so that the ratio of the wide-angle injection amount and the ratio of the narrow-angle injection amount are substantially equal,
When the needle valve 11 is fully lifted, the injection amount ratio of the large diameter injection holes 13a to 13b becomes larger than the injection amount ratio of the small diameter injection holes 12a to 12c.
【００３２】高ＥＧＲ条件下においては、高率のＥＧＲ
により燃焼温度を低下させ、同時に噴射時期を上死点以
降へ遅延させると、スモークの増加を抑えつつ、ＮＯｘ
を低減できる。この運転域では、針弁１１が初段リフト
（低リフト）に止どまるため、着火遅れの間に広角噴射
１の噴霧３１がピストン２０の下降に伴う逆スキシュに
より燃焼室２５から外側全体へ広がり、予混合燃焼の割
合が増えるため、図５のように噴射時期の遅延に伴うパ
ティキュレートの低減効果も得られる。Under high EGR conditions, high EGR
Lowering the combustion temperature, and at the same time delaying the injection timing beyond TDC, NOx
Can be reduced. In this operating range, the needle valve 11 stops at the first-stage lift (low lift), so that during the ignition delay, the spray 31 of the wide-angle injection 1 spreads from the combustion chamber 25 to the entire outside due to the reverse squish due to the lowering of the piston 20. Since the rate of premix combustion increases, the effect of reducing particulates due to the delay of the injection timing can be obtained as shown in FIG.
【００３３】高速域においては、針弁１１がフルリフト
状態になり、円弧状の面取り部１８の効果も手伝って、
広角噴射１の噴射量割合よりも、流動の弱い燃焼室２５
への狭角噴射２（その噴霧は３２で表す）の噴射量割合
が大きくなる。燃焼室２５は絞り部２１を備えるので、
その内部に強い乱流が発生するため、燃料と空気との混
合がいっそう促進され、図５のように全負荷時の出力性
能を確保できる。In the high speed range, the needle valve 11 is in a full lift state, and the effect of the arc-shaped chamfered portion 18 is also helped.
The combustion chamber 25 whose flow is weaker than the injection amount ratio of the wide-angle injection 1
The ratio of the injection amount of the narrow-angle injection 2 (the spray is represented by 32) is increased. Since the combustion chamber 25 has the throttle 21,
Since strong turbulence is generated in the inside, mixing of fuel and air is further promoted, and output performance at full load can be secured as shown in FIG.
【００３４】図６は別の実施形態を表すものであり、小
径噴孔１２ａ〜１２ｃは大径噴孔１３ａ〜１３ｃよりも
針弁１１のシート部１４へ近づけて形成される。つま
り、小径噴孔１２ａ〜１２ｃの位置は大径噴孔１３ａ〜
１３ｃの位置に対し、燃料の供給上流側に配設される。
これにより、針弁１１の低リフト時において、大径噴孔
１３ａ〜１３ｃよりも小径噴孔１２ａ〜１２ｃへの流量
割合が増えるため、広角噴射１による予混合燃焼の影響
を強めることができる。つまり、高ＥＧＲ条件下におい
て、噴射時期の遅延に伴うパティキュレートの低減効果
を促進できる。FIG. 6 shows another embodiment, in which the small diameter injection holes 12a to 12c are formed closer to the seat portion 14 of the needle valve 11 than the large diameter injection holes 13a to 13c. That is, the positions of the small diameter injection holes 12a to 12c are changed to the large diameter injection holes 13a to 13c.
It is arranged on the upstream side of the fuel supply with respect to the position 13c.
Accordingly, when the needle valve 11 is at a low lift, the flow rate to the small-diameter injection holes 12a to 12c is larger than the large-diameter injection holes 13a to 13c, so that the effect of the premixed combustion by the wide-angle injection 1 can be enhanced. That is, under the high EGR condition, the effect of reducing particulates due to the delay of the injection timing can be promoted.
【００３５】図７の実施形態では、針弁１１の低リフト
時に小径噴孔１ａ〜１２ｃと相対する環状凹部１６が針
弁１１の外周に形成される。図９において、針弁１１の
低リフト時は、上流側の小径噴孔１２ａ〜１２ｃへの流
量割合（広角噴射１の噴射量割合）がさらに増えるた
め、噴射時期の遅延に伴うパティキュレートの低減効果
は、図１０のように広角ノズル単独の性能に近づくよう
になる。In the embodiment of FIG. 7, when the needle valve 11 is at a low lift, an annular concave portion 16 facing the small diameter injection holes 1a to 12c is formed on the outer periphery of the needle valve 11. In FIG. 9, when the needle valve 11 is at a low lift, the flow rate ratio (the injection amount ratio of the wide-angle injection 1) to the upstream small-diameter injection holes 12a to 12c further increases, so that the particulates are reduced due to the delay of the injection timing. The effect comes close to the performance of the wide-angle nozzle alone as shown in FIG.
【００３６】針弁１１のフルリフト時は、図８のように
環状凹部１６が上方へ退き、針弁１１とシート部１４と
の隙間が大きくなり、小径噴孔１２ａ〜１２ｃが環状凹
部１６と相対しなくなるため、円弧状の面取り部１８を
持つ大径噴孔１３ａ〜１３ｃからの噴射量（狭角噴射２
の噴射量）の割合は大きく確保され、高速域の良好な出
力性能をもたらす（図９，図１０参照）。When the needle valve 11 is fully lifted, the annular recess 16 retreats upward as shown in FIG. 8, the gap between the needle valve 11 and the seat portion 14 increases, and the small-diameter injection holes 12a to 12c move relative to the annular recess 16. Therefore, the injection amount from the large-diameter injection holes 13a to 13c having the arc-shaped chamfered portion 18 (the narrow-angle injection 2
), And a good output performance in a high-speed range is obtained (see FIGS. 9 and 10).
【００３７】ピストン２０頂面の燃焼室２５がその最大
幅と同幅の開口部を備える場合、絞り部を持たないた
め、燃焼室２５に強い乱流は発生しないが、この燃料噴
射ノズルを適用することにより、これまでの説明と同様
の排気性能と出力性能を得ることが可能になる。その場
合、図１１において、広角噴射１による噴霧３１の衝突
位置は、ピストン上死点位置における燃焼室２５の上端
から内側へ垂直に所定距離ｘ（例えば、７ｍｍ）だけ下
がる位置を境にその上側の壁面、また狭角噴射２による
噴霧３２の衝突位置は、同じく燃焼室２５の上端から所
定距離ｘだけ下がる位置を境にその下側の壁面になるよ
うにそれぞれ設定される。When the combustion chamber 25 on the top surface of the piston 20 has an opening having the same width as the maximum width, no strong turbulent flow is generated in the combustion chamber 25 because the throttle section is not provided. By doing so, it becomes possible to obtain the same exhaust performance and output performance as described above. In this case, in FIG. 11, the collision position of the spray 31 by the wide-angle injection 1 is defined by a position vertically lower by a predetermined distance x (for example, 7 mm) inward from the upper end of the combustion chamber 25 at the piston top dead center position. The collision position of the spray 32 due to the narrow-angle injection 2 is set to be a lower wall surface at a position lower than the upper end of the combustion chamber 25 by a predetermined distance x.
【図１】この発明の実施形態を表す燃料噴射ノズルの構
成説明図である。FIG. 1 is a configuration explanatory view of a fuel injection nozzle representing an embodiment of the present invention.
【図２】同じく噴孔の配設状態を表す説明図である。FIG. 2 is an explanatory diagram showing an arrangement state of injection holes.
【図３】同じく針弁のフルリフト時を表す説明図であ
る。FIG. 3 is an explanatory view showing a full lift of the needle valve.
【図４】同じく噴射量割合の説明図である。FIG. 4 is an explanatory diagram of the injection amount ratio.
【図５】同じく効果を説明する特性図である。FIG. 5 is a characteristic diagram for explaining the same effect.
【図６】別の実施形態として噴孔の配設状態を表す説明
図である。FIG. 6 is an explanatory diagram showing an arrangement state of injection holes as another embodiment.
【図７】別の実施形態として噴孔の配設状態を表す説明
図である。FIG. 7 is an explanatory view showing an arrangement state of injection holes as another embodiment.
【図８】同じく針弁のフルリフト時を表す説明図であ
る。FIG. 8 is an explanatory diagram showing a full lift of the needle valve.
【図９】同じく噴射量割合を表す説明図である。FIG. 9 is an explanatory diagram similarly showing an injection amount ratio.
【図１０】同じく効果を説明する特性図である。FIG. 10 is a characteristic diagram illustrating the same effect.
【図１１】別の実施形態を表す噴射状態の説明図であ
る。FIG. 11 is an explanatory diagram of an injection state representing another embodiment.
【図１２】従来例の説明図である。FIG. 12 is an explanatory diagram of a conventional example.
【図１３】同じく問題点の説明図である。FIG. 13 is an explanatory diagram of the same problem.
２ 第１スプリング ３ 第２スプリング １０ｃ ノズル １１ 針弁 １２ａ〜１２ｃ 広角の小径噴孔 １３ａ〜１３ｃ 狭角の大径噴孔 １４ 針弁のシート部 １６ 環状凹部 １８ 面取り部 ２０ ピストン ２１ 絞り部 ２５ 燃焼室 ３１，３２ 噴霧 2 First spring 3 Second spring 10c Nozzle 11 Needle valve 12a to 12c Wide-angle small-diameter injection hole 13a to 13c Narrow-angle large-diameter injection hole 14 Seat portion of needle valve 16 Annular concave portion 18 Chamfered portion 20 Piston 21 Restricted portion 25 Combustion Chamber 31, 32 spray
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 ＦＩ Ｆ０２Ｂ 23/06 Ｆ０２Ｂ 23/06 Ｌ Ｆ０２Ｄ 21/08 ３０１ Ｆ０２Ｄ 21/08 ３０１Ｄ 41/02 ３２５ 41/02 ３２５Ｅ 41/04 ３３５ 41/04 ３３５Ａ ３７５ ３７５ 41/40 41/40 Ｄ 43/00 ３０１ 43/00 ３０１Ｎ ３０１Ｊ ３０１Ｇ Ｆ０２Ｍ 25/07 Ｆ０２Ｍ 25/07 Ａ ５５０ ５５０Ｒ ５７０ ５７０Ｃ 61/10 61/10 Ｄ ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 6 Identification code FI F02B 23/06 F02B 23/06 L F02D 21/08 301 F02D 21/08 301D 41/02 325 41/02 325E 41/04 335 41 / 04 335A 375 375 41/40 41/40 D 43/00 301 43/00 301N 301J 301G F02M 25/07 F02M 25/07 A 550 550R 570 570C 61/10 61/10 D
Claims (8)
するディーゼルエンジンにおいて、燃料の噴射量を制御
する針弁と、そのリフト量を運転条件に応じて制御する
手段と、針弁のリフトに伴って燃料を燃焼室に広角をも
って噴射する小径の噴孔と、針弁のリフトに伴って燃料
を燃焼室に狭角をもって噴射する大径の噴孔と、を設け
たことを特徴とする燃料噴射ノズル。In a diesel engine for injecting fuel toward a combustion chamber on a top surface of a piston, a needle valve for controlling a fuel injection amount, means for controlling a lift amount according to operating conditions, A small-diameter injection hole that injects fuel into the combustion chamber at a wide angle with the lift, and a large-diameter injection hole that injects fuel into the combustion chamber at a narrow angle with the lift of the needle valve are provided. Fuel injection nozzle.
部に流量係数を高める手段を備えたことを特徴とする請
求項１に記載の燃料噴射ノズル。2. The fuel injection nozzle according to claim 1, wherein the large-diameter injection hole is provided with a means for increasing a flow coefficient at an opening into the nozzle.
を低速域で小さく、高速域で大きく制御することを特徴
とする請求項１に記載の燃料噴射ノズル。3. The fuel injection nozzle according to claim 1, wherein the lift amount control means controls the lift amount of the needle valve to be small in a low speed range and large in a high speed range.
し、燃料の供給上流側に配設したことを特徴とする請求
項１に記載の燃料噴射ノズル。4. The fuel injection nozzle according to claim 1, wherein the position of the small-diameter injection hole is arranged on the upstream side of fuel supply with respect to the position of the large-diameter injection hole.
相対する位置に凹部を形成したことを特徴とする請求項
３に記載の燃料噴射ノズル。5. The fuel injection nozzle according to claim 3, wherein a recess is formed in the needle valve at a position facing the small diameter injection hole at the time of low lift of the needle valve.
絞り部を備え、広角の小径噴孔から噴射される噴霧の衝
突位置が、ピストン上死点位置における燃焼室の絞り部
の壁面、狭角の大径噴孔から噴射される噴霧の衝突位置
が、ピストン上死点位置における燃焼室の絞り部内側の
壁面になるようにそれぞれ設定したことを特徴とする請
求項１に記載の燃料噴射ノズル。6. The combustion chamber on the top surface of the piston is provided with a throttle at its opening, and the collision position of the spray injected from the wide-angle small-diameter injection hole is the wall of the throttle of the combustion chamber at the piston top dead center position. 2. The fuel injection system according to claim 1, wherein the collision position of the spray injected from the large-diameter injection hole having a narrow angle is set to a wall surface inside the throttle portion of the combustion chamber at the piston top dead center position. Fuel injection nozzle.
同幅の開口部を備え、広角の小径噴孔から噴射される噴
霧の衝突位置が、ピストン上死点位置における燃焼室の
上端から内側下方へ所定距離を境にその上側の壁面、狭
角の大径噴孔から噴射される噴霧の衝突位置が、同じく
所定距離の位置を境にその下側の壁面になるようにそれ
ぞれ設定したことを特徴とする請求項１に記載の燃料噴
射ノズル。7. The combustion chamber on the top surface of the piston has an opening having the same width as the maximum width of the combustion chamber, and the collision position of the spray injected from the wide-angle small-diameter injection hole is the upper end of the combustion chamber at the piston top dead center position. It is set so that the upper wall surface and the collision position of the spray injected from the large-diameter orifice with a narrow angle become the lower wall surface at a predetermined distance from the same distance downward from the inside. The fuel injection nozzle according to claim 1, wherein:
転域で噴射時期をピストン上死点以降へ遅延させる場合
に針弁のリフト量を小さく制御することを特徴とする請
求項１に記載の燃料噴射ノズル。8. The system according to claim 1, wherein the lift amount control means controls the lift amount of the needle valve to be small when the injection timing is delayed after the piston top dead center in the high EGR rate operation range. A fuel injection nozzle as described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16739597A JP3911770B2 (en) | 1997-06-24 | 1997-06-24 | Fuel injection nozzle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16739597A JP3911770B2 (en) | 1997-06-24 | 1997-06-24 | Fuel injection nozzle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1113594A true JPH1113594A (en) | 1999-01-19 |
| JP3911770B2 JP3911770B2 (en) | 2007-05-09 |
Family
ID=15848913
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16739597A Expired - Fee Related JP3911770B2 (en) | 1997-06-24 | 1997-06-24 | Fuel injection nozzle |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3911770B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001227344A (en) * | 2000-02-14 | 2001-08-24 | Mitsubishi Heavy Ind Ltd | Nozzle hole structure of torch ignition-type gas engine |
| EP1876332A1 (en) * | 2005-04-19 | 2008-01-09 | Yanmar Co., Ltd. | Direct injection diesel engine |
| KR100960333B1 (en) | 2008-06-23 | 2010-06-07 | 부산대학교 산학협력단 | A fuel injection nozzle for diesel engine |
| WO2014188598A1 (en) * | 2013-05-24 | 2014-11-27 | トヨタ自動車株式会社 | Fuel injection valve for internal combustion engine |
| JP2015172357A (en) * | 2014-03-12 | 2015-10-01 | 株式会社日本自動車部品総合研究所 | fuel injection valve |
| JP2017008877A (en) * | 2015-06-25 | 2017-01-12 | 日立オートモティブシステムズ株式会社 | Fuel injection valve |
| JP2017190753A (en) * | 2016-04-15 | 2017-10-19 | 株式会社デンソー | Fuel injection valve |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0921321A (en) * | 1995-07-05 | 1997-01-21 | Toyota Autom Loom Works Ltd | Fuel injection method for direct injection type diesel engine, piston and injection nozzle employed by the method |
-
1997
- 1997-06-24 JP JP16739597A patent/JP3911770B2/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0921321A (en) * | 1995-07-05 | 1997-01-21 | Toyota Autom Loom Works Ltd | Fuel injection method for direct injection type diesel engine, piston and injection nozzle employed by the method |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001227344A (en) * | 2000-02-14 | 2001-08-24 | Mitsubishi Heavy Ind Ltd | Nozzle hole structure of torch ignition-type gas engine |
| EP1876332A1 (en) * | 2005-04-19 | 2008-01-09 | Yanmar Co., Ltd. | Direct injection diesel engine |
| EP1876332A4 (en) * | 2005-04-19 | 2009-06-17 | Yanmar Co Ltd | Direct injection diesel engine |
| KR100960333B1 (en) | 2008-06-23 | 2010-06-07 | 부산대학교 산학협력단 | A fuel injection nozzle for diesel engine |
| WO2014188598A1 (en) * | 2013-05-24 | 2014-11-27 | トヨタ自動車株式会社 | Fuel injection valve for internal combustion engine |
| JP2015172357A (en) * | 2014-03-12 | 2015-10-01 | 株式会社日本自動車部品総合研究所 | fuel injection valve |
| JP2017008877A (en) * | 2015-06-25 | 2017-01-12 | 日立オートモティブシステムズ株式会社 | Fuel injection valve |
| JP2017190753A (en) * | 2016-04-15 | 2017-10-19 | 株式会社デンソー | Fuel injection valve |
| WO2017179323A1 (en) * | 2016-04-15 | 2017-10-19 | 株式会社デンソー | Fuel injection valve |
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