JPH09317604A - Direct injection type diesel engine - Google Patents
Direct injection type diesel engineInfo
- Publication number
- JPH09317604A JPH09317604A JP8130007A JP13000796A JPH09317604A JP H09317604 A JPH09317604 A JP H09317604A JP 8130007 A JP8130007 A JP 8130007A JP 13000796 A JP13000796 A JP 13000796A JP H09317604 A JPH09317604 A JP H09317604A
- Authority
- JP
- Japan
- Prior art keywords
- injector
- cavity
- fuel
- injection
- side wall
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
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
- F02B23/02—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
- F02B23/0663—Details related to the fuel injector or the fuel spray having multiple injectors per 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
- 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
- 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
- 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)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Combustion Methods Of Internal-Combustion Engines (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、直接噴射式ディー
ゼルエンジンに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct injection diesel engine.
【０００２】[0002]
【従来の技術】最近、比較的小型のディーゼルエンジン
にも直接噴射式のものが採用されており、これは燃費の
点では副室式よりも有利であるが、他の排ガス特性、例
えば未燃燃料（ＨＣ）、排気微粒子（スモーク）、ＮＯ
ｘ等の点では不利であり、近年の厳しい排ガス規制をク
リアし難いという問題がある。2. Description of the Related Art Recently, a direct injection type is also adopted for a relatively small diesel engine, which is more advantageous in terms of fuel consumption than the sub-chamber type, but has another exhaust gas characteristic such as unburned combustion. Fuel (HC), exhaust particulate (smoke), NO
It is disadvantageous in terms of x and the like, and there is a problem that it is difficult to pass the recent severe exhaust gas regulations.
【０００３】図５は、特にＨＣとスモークとの排出量の
関係を示したグラフである。ここで横軸には、燃焼室
（キャビティ）径Ｄとシリンダボア径Ｂとの比D/B がと
ってある。また、ＨＣについては一定の低負荷運転時の
場合を示し、スモークについては一定の高負荷運転時の
場合を示している。FIG. 5 is a graph showing the relationship between the amounts of HC and smoke discharged. Here, the horizontal axis shows the ratio D / B between the diameter D of the combustion chamber (cavity) and the diameter B of the cylinder bore. Further, HC shows the case of a constant low load operation, and smoke shows the case of a constant high load operation.
【０００４】これから分かるように、D/B の変化につ
れ、ＨＣとスモークとの排出量はトレードオフの関係に
ある。そして、ボア径Ｂを一定と仮定して、キャビティ
径Ｄを小とした場合には高負荷スモークは低減し、低負
荷ＨＣは増加する。逆に、キャビティ径Ｄを大とした場
合には、高負荷スモークは増加し低負荷ＨＣは低減す
る。As can be seen from the above, as the D / B changes, the emissions of HC and smoke are in a trade-off relationship. Then, assuming that the bore diameter B is constant and the cavity diameter D is small, the high load smoke decreases and the low load HC increases. On the contrary, when the cavity diameter D is increased, the high load smoke increases and the low load HC decreases.
【０００５】これは次のような理由による。先ずD/B が
小さいと、キャビティの略中心に臨まされたインジェク
タの複数の噴口と、キャビティの周側壁との距離が短く
なる。そして低負荷運転の場合はシリンダ内温度が低い
ため、各噴口から噴射された燃料はキャビティの周側壁
に衝突し、大部分が蒸発しきれず周側壁にそのまま付着
するようになる。そしてこの付着燃料が未燃燃料となり
ＨＣとして排出されてしまう。This is for the following reason. First, if D / B is small, the distance between the plurality of injector nozzles facing the approximate center of the cavity and the peripheral side wall of the cavity becomes short. In the case of low load operation, the temperature in the cylinder is low, so that the fuel injected from each injection port collides with the peripheral side wall of the cavity, and most of the fuel cannot evaporate and adheres to the peripheral side wall as it is. Then, this attached fuel becomes unburned fuel and is discharged as HC.
【０００６】一方、高負荷運転の場合だと、シリンダ内
温度が十分に高温であるので、噴射量が多くとも略完全
燃焼を行え、ＨＣ、スモークともに低減できる。On the other hand, in the case of high load operation, since the temperature in the cylinder is sufficiently high, almost complete combustion can be performed even if the injection amount is large, and both HC and smoke can be reduced.
【０００７】次に、D/B が大きいと、噴口とキャビティ
周側壁との距離が長くなる。このため、噴射された燃料
は、シリンダ内温度の低い低負荷運転時でもキャビティ
周側壁に到達する前に蒸発、気化するようになり、これ
によってＨＣの排出量が減少する。Next, if D / B is large, the distance between the injection port and the side wall of the cavity becomes long. For this reason, the injected fuel is vaporized and vaporized before reaching the peripheral wall of the cavity even during low load operation in which the temperature in the cylinder is low, whereby the amount of HC discharged is reduced.
【０００８】しかし、その反面、キャビティ内のスワー
ル保存性が悪化し、スワールが減衰し易くなるため、噴
射量の多い高負荷時では、空気と燃料との混合が悪化し
てスモークが増加してしまう。また噴射燃料とキャビテ
ィ周側壁との衝突も弱まり、衝突による燃料の微粒化、
かく乱が弱まってしまう。On the other hand, on the other hand, the swirl preservability in the cavity is deteriorated and the swirl is easily attenuated. Therefore, when the injection amount is high and the load is high, the mixture of air and fuel is deteriorated and smoke is increased. I will end up. Further, the collision between the injected fuel and the side wall of the cavity also weakens, and the atomization of fuel due to the collision,
The disturbance will be weakened.
【０００９】[0009]
【発明が解決しようとする課題】そこで、この対策とし
て、D/B を比較的小さな値として高負荷運転時の性能を
維持する一方、低負荷運転時には噴射圧を下げて噴霧の
到達距離（貫徹力）を減らし、燃料の蒸発・気化を促進
することが考えられる。Therefore, as a countermeasure against this, D / B is set to a relatively small value to maintain the performance at high load operation, while at the time of low load operation, the injection pressure is reduced to reach the spray (penetration). Power) to accelerate the evaporation and vaporization of fuel.
【００１０】しかしこうすると、噴口間に噴射のバラツ
キが生じ、例えば５噴口のうち３噴口しか噴射しないな
ど、実際の噴射圧力は高いままとなり噴霧の到達距離を
減らすことができない。However, in this case, there is a variation in the injection between the injection ports, and the actual injection pressure remains high, for example, only three of the five injection ports are injected, and it is not possible to reduce the reaching distance of the spray.
【００１１】また、一般にインジェクタはキャビティの
略中心に臨まされるので、インジェクタの噴口とキャビ
ティ周側壁との距離は比較的小さく、噴射圧を下げて噴
霧の到達距離を減らす方法にも物理的に限界がある。Further, since the injector is generally faced to the approximate center of the cavity, the distance between the injector's injection port and the cavity peripheral side wall is relatively small, and the method of lowering the injection pressure to reduce the reaching distance of the spray is physically required. There is a limit.
【００１２】[0012]
【課題を解決するための手段】本発明に係る直接噴射式
ディーゼルエンジンは、ピストンの頂面にキャビティを
設け、このキャビティの略中心に臨ませて第１インジェ
クタを配設すると共に、上記キャビティの開口端縁に臨
ませて第２インジェクタを配設し、上記第１インジェク
タには、上記キャビティの周側壁に向けて放射状に燃料
を噴射する複数の第１噴口を設け、上記第２インジェク
タには、上記キャビティの径方向反対側の周側壁に向け
て燃料を噴射する単一の第２噴口を設けたものである。In a direct injection diesel engine according to the present invention, a cavity is provided on the top surface of a piston, and a first injector is disposed so as to face the center of the cavity. A second injector is arranged so as to face the opening edge, and the first injector is provided with a plurality of first injection holes for radially injecting fuel toward the peripheral side wall of the cavity, and the second injector is provided in the second injector. A single second injection port for injecting fuel is provided toward the radially opposite side wall of the cavity.
【００１３】これにおいては、第２噴口とその噴射燃料
が指向される周側壁との距離を最大にとることができ
る。よって、その第２噴口からの噴霧の到達距離も最大
にすることができ、低負荷運転時にこの第２噴口から燃
料噴射を行うことにより、周側壁到達前には燃料の蒸発
・気化を促進し、周側壁到達後は燃料付着を抑制するこ
とができる。これによって、前述の低負荷ＨＣの問題を
効果的に解決できるようになる。In this case, the distance between the second injection port and the peripheral side wall to which the injected fuel is directed can be maximized. Therefore, the reaching distance of the spray from the second injection port can be maximized, and by injecting the fuel from the second injection port at the time of low load operation, the evaporation / vaporization of the fuel is promoted before reaching the peripheral side wall. After reaching the peripheral side wall, fuel adhesion can be suppressed. This makes it possible to effectively solve the above-mentioned problem of low load HC.
【００１４】[0014]
【発明の実施の形態】以下、本発明の好適な実施の形態
を添付図面に基づいて詳述する。Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
【００１５】図１は、本発明に係る直接噴射式ディーゼ
ルエンジンを示す縦断面図である。図示するようにエン
ジン１においては、シリンダ２内にピストン３が往復摺
動可能に設けられ、シリンダ２にはガスケット４を介し
てシリンダヘッド５が取り付けられる。ピストン３の頂
部にはキャビティ６が設けられ、このキャビティ６が実
質的な燃焼室を区画形成する。ここでキャビティ６の開
口部の直径（キャビティ径）をＤとし、シリンダボアの
直径をＢとすると、その直径比D/B は前述の如く比較的
小さく、高負荷運転時でもキャビティ６内のスワール保
存性を悪化させないような最適値とされている。またシ
リンダヘッド５には二つのインジェクタ、即ち第１イン
ジェクタ７と第２インジェクタ８とが取り付けられる。FIG. 1 is a vertical sectional view showing a direct injection diesel engine according to the present invention. As shown in the figure, in the engine 1, a piston 3 is provided in a cylinder 2 so as to be able to reciprocate, and a cylinder head 5 is attached to the cylinder 2 via a gasket 4. A cavity 6 is provided at the top of the piston 3, and the cavity 6 defines a substantial combustion chamber. Here, if the diameter of the opening of the cavity 6 (cavity diameter) is D and the diameter of the cylinder bore is B, the diameter ratio D / B is relatively small as described above, and swirl preservation in the cavity 6 even during high load operation. It is set to the optimum value that does not deteriorate the sex. Two injectors, that is, a first injector 7 and a second injector 8 are attached to the cylinder head 5.
【００１６】キャビティ６は、ピストン３に有底円筒状
の窪みを形成し、その底部と側部とを結ぶコーナー部に
沿って円環状の窪みを形成したような形状とされる。そ
してキャビティ６はピストン３に対し偏心されることな
く、その中心がシリンダ中心に一致される。一方、第１
インジェクタ７もシリンダ中心に沿って配置され、特に
その燃料噴射を行う先端部９はシリンダ中心に位置さ
れ、キャビティ６の中心に臨まされる。また、第２イン
ジェクタ８は、第１インジェクタ７の径方向外側に傾斜
状態で配置され、特にその燃料噴射を行う先端部１０
は、ピストン３の頂面でキャビティ６の開口部を区画す
るキャビティ６の開口端縁１１に臨まされる。なお第２
インジェクタ８は、ここでは図示しない二つの排気弁の
間の位置に配設されている。また、第１インジェクタ７
の先端部９の位置はシリンダ中心から若干ずらすことも
可能である。The cavity 6 has such a shape that a cylindrical bottomed hollow is formed in the piston 3 and an annular hollow is formed along a corner connecting the bottom and the side. The center of the cavity 6 is aligned with the center of the cylinder without being eccentric to the piston 3. On the other hand, the first
The injector 7 is also arranged along the center of the cylinder, and particularly the tip portion 9 for injecting the fuel is located at the center of the cylinder and faces the center of the cavity 6. Further, the second injector 8 is arranged radially outward of the first injector 7 in an inclined state, and particularly the tip portion 10 for injecting fuel thereof.
Faces the opening end edge 11 of the cavity 6 that defines the opening of the cavity 6 at the top surface of the piston 3. The second
The injector 8 is arranged at a position between two exhaust valves (not shown). Also, the first injector 7
The position of the tip portion 9 of the cylinder can be slightly displaced from the center of the cylinder.
【００１７】図２はピストン３を平面的に見た図で、こ
れには各インジェクタ７，８の先端部９，１０の位置が
示されている。ここで第１インジェクタ７の先端部９に
は五つの第１噴口（図示せず）が設けられ、これら第１
噴口はそれぞれキャビティ６の周側壁１２に向けて、燃
料Ｆ1 を周方向等間隔で放射状に噴射するようになって
いる。一方、第２インジェクタ８も同様に、その先端部
１０に第２噴口（図示せず）を有するが、この第２噴口
は一つのみが設けられつまり単一とされて、キャビティ
６の径方向反対側の周側壁１２に向けて燃料Ｆ2 を噴射
するようになっている。なおここでは燃料Ｆ2 は、第１
噴口から噴射される一本の燃料Ｆ1 と同方向に噴射され
る。またキャビティ６の周側壁１２とは、キャビティ６
内の周方向に沿った側壁のことを意味する。FIG. 2 is a plan view of the piston 3, in which the positions of the tips 9 and 10 of the injectors 7 and 8 are shown. Here, the first injector 7 is provided with five first injection ports (not shown) at the tip portion 9 thereof.
The nozzles are adapted to radially inject the fuel F 1 toward the peripheral side wall 12 of the cavity 6 at equal intervals in the circumferential direction. On the other hand, similarly, the second injector 8 also has a second injection port (not shown) at its tip portion 10, but only one second injection port is provided, that is, a single injection port is provided, and the second injection port 8 is formed in the radial direction of the cavity 6. The fuel F 2 is injected toward the opposite side wall 12 on the opposite side. Note that here, the fuel F 2 is the first
It is injected in the same direction as the one fuel F 1 injected from the injection port. Further, the peripheral side wall 12 of the cavity 6 means the cavity 6
It means a side wall along the inner circumferential direction.
【００１８】ここで各インジェクタ７，８には、コモン
レール１３に貯留された比較的高圧の燃料が配管１４，
１６を介して送られる。そしてこれらインジェクタ７，
８には電磁弁、ニードル弁及び増圧ピストン等が内蔵さ
れている。電磁弁は、コントローラとしてのECU １５か
ら制御信号を受けてON/OFF制御される。そして増圧ピス
トンは、電磁弁がONとされたとき、インジェクタ内部の
燃料を加圧してニードル弁をリフトさせ、同時にその燃
料を噴口から噴射させる。このように、第１及び第２イ
ンジェクタ７，８はコモンレール式燃料噴射装置の一部
を構成している。Here, the fuel of relatively high pressure stored in the common rail 13 is piped into each of the injectors 7 and 8.
Sent via 16. And these injectors 7,
A solenoid valve, a needle valve, a pressure boosting piston, etc. are built in 8. The solenoid valve is ON / OFF controlled by receiving a control signal from the ECU 15 as a controller. When the solenoid valve is turned on, the pressure boosting piston pressurizes the fuel inside the injector to lift the needle valve and at the same time inject the fuel from the injection port. As described above, the first and second injectors 7 and 8 form a part of the common rail fuel injection device.
【００１９】ここでECU １５は、エンジン回転数セン
サ、水温センサ、アクセル開度センサ、クランク角セン
サ等から送られてくる信号に基づき、各インジェクタ
７，８による燃料噴射制御、或いは噴射時期の制御等の
各種制御を実行するようになっている。特にアクセル開
度センサは、エンジン負荷を検出するための負荷検出手
段を形成し、ECU １５はこれによるアクセル開度信号に
基づきエンジン負荷を決定する。Here, the ECU 15 controls the fuel injection by the injectors 7 and 8 or controls the injection timing based on signals sent from an engine speed sensor, a water temperature sensor, an accelerator opening sensor, a crank angle sensor and the like. And so on. In particular, the accelerator opening sensor forms a load detecting means for detecting the engine load, and the ECU 15 determines the engine load based on the accelerator opening signal.
【００２０】また、ECU １５は、コモンレール１３に接
続される図示しないフィードポンプにも制御信号を出力
し、フィードポンプの流量制御弁を制御している。これ
によって、コモンレール１３内の燃料圧（噴射圧）は最
適に制御される。The ECU 15 also outputs a control signal to a feed pump (not shown) connected to the common rail 13 to control the flow control valve of the feed pump. As a result, the fuel pressure (injection pressure) in the common rail 13 is optimally controlled.
【００２１】さて、上記構成にあっては、特に第２イン
ジェクタ８の先端部１０をキャビティ６の開口端縁１１
に臨ませ、第２噴口をキャビティ６の径方向反対側の周
側壁１２に向けて指向させたため、第２噴口とその噴射
燃料Ｆ2 が向けられる周側壁１２との距離を最大にとる
ことができる。よって、その第２噴口からの噴霧の到達
距離も最大にすることができ、シリンダ内温度が低い低
負荷運転時でも第２噴口のみから燃料噴射を行うことに
より、周側壁到達前には燃料の蒸発・気化を促進し、周
側壁到達後は燃料付着を抑制することができる。これに
よって、前述の低負荷ＨＣの問題を効果的に解決できる
ようになる。In the above structure, the tip portion 10 of the second injector 8 is particularly connected to the opening edge 11 of the cavity 6.
Since the second injection port is directed toward the circumferential side wall 12 on the opposite side in the radial direction of the cavity 6, it is possible to maximize the distance between the second injection port and the circumferential side wall 12 to which the injected fuel F 2 is directed. it can. Therefore, the reaching distance of the spray from the second injection port can be maximized, and the fuel is injected from only the second injection port even during the low load operation where the temperature in the cylinder is low, so that the fuel can be injected before reaching the peripheral side wall. Evaporation / vaporization can be promoted, and fuel adhesion can be suppressed after reaching the peripheral side wall. This makes it possible to effectively solve the above-mentioned problem of low load HC.
【００２２】またこのときには単一の第２噴口から燃料
噴射を行うので、噴霧のバラツキもなく安定した燃料噴
射を行える。そしてこれにより、着火遅れ期間中の噴射
量を少なくすることができ、即ち噴射率を低くすること
ができ、燃焼初期の熱発生率を抑え、ＮＯｘを低減する
ことができる。Further, at this time, since the fuel is injected from the single second injection port, stable fuel injection can be performed without variations in the spray. Thus, the injection amount during the ignition delay period can be reduced, that is, the injection rate can be reduced, the heat generation rate in the early stage of combustion can be suppressed, and NOx can be reduced.
【００２３】さらに、高負荷運転の際は直径比D/B が比
較的小さいため、キャビティ内のスワール保存性を良好
とし、空気と燃料との混合を促進してスモークを抑制で
きる。またこれによってＥＧＲを行うことも可能とな
り、高負荷運転時におけるスモークとＨＣとの同時低減
を図ることができる。Further, since the diameter ratio D / B is relatively small during high load operation, the swirl preservability in the cavity can be improved, and the mixture of air and fuel can be promoted to suppress smoke. This also makes it possible to perform EGR, and it is possible to simultaneously reduce smoke and HC during high load operation.
【００２４】次に、図３は上記エンジン１の燃料噴射制
御マップを示している。横軸にはエンジン回転数が、縦
軸にはエンジン負荷がとってある。このマップに従って
ECU１５は燃料噴射制御を実行し、ECU １５はエンジン
回転数に拘らず、エンジン負荷が全負荷(100(%))に対し
Ａ＝20(%) 以下となる領域（ハッチングで示す）で、第
１インジェクタ７による燃料噴射を停止し、第２インジ
ェクタ８の第２噴口のみから燃料噴射を行うようになっ
ている。またそれ以外の領域では、第１インジェクタ７
のみによる燃料噴射を実行し、第２インジェクタ８によ
る燃料噴射を停止するようになっている。Next, FIG. 3 shows a fuel injection control map of the engine 1. The horizontal axis represents the engine speed and the vertical axis represents the engine load. According to this map
The ECU 15 executes fuel injection control, and the ECU 15 controls the engine load to be A = 20 (%) or less with respect to the full load (100 (%)) regardless of the engine speed (hatched). The fuel injection by the one injector 7 is stopped, and the fuel injection is performed only from the second injection port of the second injector 8. In other areas, the first injector 7
Only the fuel injection by the second injector 8 is stopped and the fuel injection by the second injector 8 is stopped.
【００２５】また、図４は別の燃料噴射制御マップを示
し、これにおいてはハッチングで示すように、エンジン
負荷がＡ＝20(%) 以下で且つエンジン回転数がＮ＝ 100
0(rpm)以下の領域で、第１インジェクタ７による燃料噴
射を停止し、第２インジェクタ８のみから燃料噴射を行
うようになっている。またそれ以外の領域では、第１イ
ンジェクタ７のみによる燃料噴射を実行している。FIG. 4 shows another fuel injection control map, in which, as indicated by hatching, the engine load is A = 20 (%) or less and the engine speed is N = 100.
In the region of 0 (rpm) or less, the fuel injection by the first injector 7 is stopped, and the fuel injection is performed only by the second injector 8. In the other regions, fuel injection is performed only by the first injector 7.
【００２６】このようなインジェクタの切替制御によ
り、低負荷運転時には第２インジェクタ８のみから燃料
噴射を行ってＨＣの低減が可能となるが、上記で示した
エンジン負荷或いは回転数の切替ポイントは、エンジン
特性に合わせて他の値に変更が可能である。なお、高負
荷運転時において、第１インジェクタ７と第２インジェ
クタ８との両方で燃料噴射を行うことも可能である。た
だしこの場合は、互いの噴射燃料Ｆ1 ，Ｆ2 同士が干渉
して過濃領域が生成されぬよう、第１及び第２噴口の指
向方向を設定する必要がある。By such injector switching control, it is possible to inject fuel only from the second injector 8 during low load operation to reduce HC, but the above-mentioned engine load or engine speed switching points are: Other values can be changed according to the engine characteristics. It is also possible to perform fuel injection by both the first injector 7 and the second injector 8 during high load operation. However, in this case, it is necessary to set the directing directions of the first and second injection ports so that the injected fuels F 1 and F 2 do not interfere with each other to generate a rich region.
【００２７】以上、本発明の好適な実施の形態について
説明してきたが、本発明は上記形態に限定されず他の様
々な形態を採ることが可能である。例えば、第１インジ
ェクタの噴口数を六つ等に変更することもできるし、キ
ャビティの形状を皿形や四角形等の他の形状に変えるこ
ともできる。Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, but can take various other forms. For example, the number of injection holes of the first injector can be changed to six or the like, and the shape of the cavity can be changed to another shape such as a dish or a square.
【００２８】[0028]
【発明の効果】本発明は次の如き優れた効果を発揮す
る。The present invention exhibits the following excellent effects.
【００２９】（１） 低負荷運転時において燃料の蒸
発、気化を促進し、ＨＣの排出量を低減することができ
る。(1) It is possible to promote the evaporation and vaporization of fuel during a low load operation, and reduce the amount of HC discharged.
【００３０】（２） 低負荷運転時において噴射率を下
げられ、ＮＯｘの排出量を低減することができる。(2) The injection rate can be reduced during low load operation, and the NOx emission amount can be reduced.
【図１】本発明に係る直接噴射式ディーゼルエンジンを
示す縦断面図である。FIG. 1 is a vertical cross-sectional view showing a direct injection diesel engine according to the present invention.
【図２】ピストンを示す平面図である。FIG. 2 is a plan view showing a piston.
【図３】本発明に係る直接噴射式ディーゼルエンジンの
燃料噴射制御マップである。FIG. 3 is a fuel injection control map of the direct injection diesel engine according to the present invention.
【図４】本発明に係る直接噴射式ディーゼルエンジンの
別の燃料噴射制御マップである。FIG. 4 is another fuel injection control map of the direct injection diesel engine according to the present invention.
【図５】ＨＣ及びスモークの排出量の関係を示すグラフ
である。FIG. 5 is a graph showing the relationship between HC and smoke emissions.
１ 直接噴射式ディーゼルエンジン ３ ピストン ６ キャビティ ７ 第１インジェクタ ８ 第２インジェクタ １１ 開口端縁 １２ 周側壁 １５ ECU （コントローラ） Ｆ1 ，Ｆ2 燃料1 Direct Injection Diesel Engine 3 Piston 6 Cavity 7 First Injector 8 Second Injector 11 Open End Edge 12 Circumferential Side Wall 15 ECU (Controller) F 1 , F 2 Fuel
Claims (2)
キャビティの略中心に臨ませて第１インジェクタを配設
すると共に、上記キャビティの開口端縁に臨ませて第２
インジェクタを配設し、上記第１インジェクタには、上
記キャビティの周側壁に向けて放射状に燃料を噴射する
複数の第１噴口を設け、上記第２インジェクタには、上
記キャビティの径方向反対側の周側壁に向けて燃料を噴
射する単一の第２噴口を設けたことを特徴とする直接噴
射式ディーゼルエンジン。1. A cavity is provided on a top surface of a piston, a first injector is disposed so as to face the center of the cavity, and a second injector is disposed so as to face an opening edge of the cavity.
An injector is provided, the first injector is provided with a plurality of first injection ports for injecting fuel radially toward the peripheral side wall of the cavity, and the second injector is provided on the opposite side in the radial direction of the cavity. A direct injection diesel engine having a single second injection port for injecting fuel toward the peripheral side wall.
手段と、該負荷検出手段による検出値が所定値より小さ
いときに、上記第１インジェクタによる燃料噴射を停止
し且つ上記第２インジェクタによる燃料噴射を実行する
コントローラとが設けられた請求項１記載の直接噴射式
ディーゼルエンジン。2. A load detection means for detecting an engine load, and when the detection value by the load detection means is smaller than a predetermined value, the fuel injection by the first injector is stopped and the fuel injection by the second injector is stopped. A direct injection diesel engine according to claim 1, further comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8130007A JPH09317604A (en) | 1996-05-24 | 1996-05-24 | Direct injection type diesel engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8130007A JPH09317604A (en) | 1996-05-24 | 1996-05-24 | Direct injection type diesel engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09317604A true JPH09317604A (en) | 1997-12-09 |
Family
ID=15023850
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8130007A Pending JPH09317604A (en) | 1996-05-24 | 1996-05-24 | Direct injection type diesel engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09317604A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010196506A (en) * | 2009-02-23 | 2010-09-09 | Hitachi Automotive Systems Ltd | Cylinder injection internal combustion engine |
| WO2015117834A1 (en) * | 2014-02-10 | 2015-08-13 | IFP Energies Nouvelles | Internal combustion engine with injection of two fuel jets at different flow rates, and fuel-injection method for such an engine |
| CN112879147A (en) * | 2021-01-25 | 2021-06-01 | 华中科技大学 | Oil injection system suitable for high power density diesel engine |
-
1996
- 1996-05-24 JP JP8130007A patent/JPH09317604A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010196506A (en) * | 2009-02-23 | 2010-09-09 | Hitachi Automotive Systems Ltd | Cylinder injection internal combustion engine |
| WO2015117834A1 (en) * | 2014-02-10 | 2015-08-13 | IFP Energies Nouvelles | Internal combustion engine with injection of two fuel jets at different flow rates, and fuel-injection method for such an engine |
| FR3017421A1 (en) * | 2014-02-10 | 2015-08-14 | IFP Energies Nouvelles | INTERNAL COMBUSTION ENGINE WITH INJECTION OF TWO DIFFERENTIATED FLOW FUEL TANKS AND FUEL INJECTION METHOD FOR SUCH A MOTOR. |
| CN106164465A (en) * | 2014-02-10 | 2016-11-23 | Ifp新能源公司 | There is internal combustion engine and the fuel injection method thereof of two fuel sheet injections of different flow rate |
| US10240569B2 (en) | 2014-02-10 | 2019-03-26 | IFP Energies Nouvelles | Internal combustion engine with injection of two fuel jets at different flow rates and fuel-injection method for such an engine |
| CN112879147A (en) * | 2021-01-25 | 2021-06-01 | 华中科技大学 | Oil injection system suitable for high power density diesel engine |
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