JP2759375B2 - Direct injection internal combustion engine - Google Patents
Direct injection internal combustion engineInfo
- Publication number
- JP2759375B2 JP2759375B2 JP2134755A JP13475590A JP2759375B2 JP 2759375 B2 JP2759375 B2 JP 2759375B2 JP 2134755 A JP2134755 A JP 2134755A JP 13475590 A JP13475590 A JP 13475590A JP 2759375 B2 JP2759375 B2 JP 2759375B2
- Authority
- JP
- Japan
- Prior art keywords
- injection
- air
- pressure
- inner peripheral
- internal combustion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000002347 injection Methods 0.000 title claims description 74
- 239000007924 injection Substances 0.000 title claims description 74
- 238000002485 combustion reaction Methods 0.000 title claims description 53
- 239000000446 fuel Substances 0.000 claims description 34
- 230000002093 peripheral effect Effects 0.000 claims description 30
- 238000001816 cooling Methods 0.000 claims description 15
- 230000003134 recirculating effect Effects 0.000 claims 1
- 239000007921 spray Substances 0.000 description 11
- 239000007789 gas Substances 0.000 description 9
- 230000007423 decrease Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 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
- F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
- F02B29/04—Cooling of air intake supply
- F02B29/0481—Intake air cooling by means others than heat exchangers, e.g. by rotating drum regenerators, cooling by expansion or by electrical means
-
- 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
- F02B23/0648—Means or methods to improve the spray dispersion, evaporation or ignition
- F02B23/0651—Means or methods to improve the spray dispersion, evaporation or ignition the fuel spray impinging on reflecting surfaces or being specially guided throughout the combustion space
-
- 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
- F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
- F02B29/04—Cooling of air intake supply
- F02B29/0406—Layout of the intake air cooling or coolant circuit
- F02B29/0412—Multiple heat exchangers arranged in parallel or in series
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/02—EGR systems specially adapted for supercharged engines
- F02M26/08—EGR systems specially adapted for supercharged engines for engines having two or more intake charge compressors or exhaust gas turbines, e.g. a turbocharger combined with an additional compressor
-
- 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
- F02B23/0618—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 having in-cylinder means to influence the charge motion
- F02B23/0621—Squish flow
-
- 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
- F02B23/0696—W-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 wall
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
- F02M26/02—EGR systems specially adapted for supercharged engines
- F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
- F02M26/05—High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
-
- 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)
- Thermal Sciences (AREA)
- Physics & Mathematics (AREA)
- Dispersion Chemistry (AREA)
- 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)
- Output Control And Ontrol Of Special Type Engine (AREA)
Description
【発明の詳細な説明】 (産業上の利用分野) 本発明は、排気タービン過給機及びインタークーラを
備え、ピストン上壁に形成された燃焼室に燃料噴射弁か
ら直接燃料を噴射する直接噴射式内燃機関に関する。The present invention relates to a direct injection that includes an exhaust turbine supercharger and an intercooler, and directly injects fuel from a fuel injection valve into a combustion chamber formed on an upper wall of a piston. The present invention relates to an internal combustion engine.
(従来の技術) 第11図はこの種内燃機関の一般的な全体構造を示して
おり、機関の両側に給気マニホルド21及び排気マニホル
ド22を備え、排気マニホルド22に排気タービン過給機24
のタービン部25を接続し、コンプレッサ部26はインター
クーラ27を介して給気マニホルド21に接続している。吸
気の温度が例えば略20℃であるとすると、過給機24のコ
ンプレッサ部26で圧縮されることにより略100℃に上昇
し、インタークーラ27で40℃〜50℃に冷却されて給気マ
ニホルド21に供給される。(Prior Art) FIG. 11 shows a general overall structure of an internal combustion engine of this kind. The engine has an intake manifold 21 and an exhaust manifold 22 on both sides of the engine, and the exhaust manifold 22 has an exhaust turbine supercharger 24.
And a compressor unit 26 is connected to the air supply manifold 21 via an intercooler 27. Assuming that the temperature of the intake air is, for example, approximately 20 ° C., the air temperature rises to approximately 100 ° C. by being compressed by the compressor unit 26 of the supercharger 24, and is cooled to 40 ° C. to 50 ° C. by the intercooler 27, and Supplied to 21.
従来の燃焼室としては、第9図のようなトロイダル型
あるいは第10図のような内周テーパー面を有するスキッ
シュリップ型等があり、これらの燃焼室には燃料の噴霧
を抑制する手段は講じられていない。Conventional combustion chambers include a toroidal type as shown in FIG. 9 and a squish lip type having an inner peripheral tapered surface as shown in FIG. 10. In these combustion chambers, means for suppressing fuel spray is provided. Not been.
また従来の燃料制御噴射系は、噴射カム形状の変更に
より第12図に示すように噴射圧を高圧化すると、噴射初
期から急速に燃料噴射率が上昇するため、燃料弁が開く
と同時に一気に噴射量が増加する。このような状態で燃
焼させると、燃料噴射開始後、着火遅れ期間中に多量の
燃料が高圧化により微粒化され、着火時には多量の空気
と混合した燃料が一気に燃焼する。この時の燃焼場は、
空気を圧縮しての圧力及び温度が高く、かつ酸素濃度が
標準空気と同一のため、火炎温度が非常に高く、NOxが
多く排出する。即ち燃焼初期におけるNOxの排出量が多
くなるという不具合が生じる。Also, in the conventional fuel control injection system, when the injection pressure is increased as shown in Fig. 12 by changing the injection cam shape, the fuel injection rate rises rapidly from the initial stage of injection, so that the fuel valve is opened and the injection is performed at once. The amount increases. When the fuel is burned in such a state, a large amount of fuel is atomized by the high pressure during the ignition delay period after the start of fuel injection, and at the time of ignition, the fuel mixed with a large amount of air burns at once. The combustion field at this time is
Since the pressure and temperature of the compressed air are high and the oxygen concentration is the same as the standard air, the flame temperature is very high and a large amount of NOx is emitted. That is, there is a problem that the amount of NOx emission in the early stage of combustion increases.
(発明の目的) 本発明の目的は、給気温度の低減、燃料噴射率及び噴
射圧の制御並びに燃焼室形状の工夫により、燃焼初期に
生成されるNOxの低減効果を向上させ、燃焼中期以降で
は燃料噴射圧の高圧化及びバックスキッシュの渦流等に
より混合気形成を良くして、出力性能を向上させると共
に、黒煙の発生を減少させることである。(Object of the Invention) An object of the present invention is to improve the effect of reducing NOx generated in the early stage of combustion by reducing the supply air temperature, controlling the fuel injection rate and the injection pressure, and devising the shape of the combustion chamber. The purpose of the present invention is to improve the air-fuel mixture by increasing the fuel injection pressure and the back squish vortex, thereby improving the output performance and reducing the generation of black smoke.
(目的を達成するための技術的手段) 上記目的を達成するために本発明は、 燃料噴射率及び燃料噴射圧を、上死点付近の燃焼初期
で抑制し、燃焼中期、後期で増大、高圧化させる燃料制
御噴射系と、 燃焼室の内周面を上端部が狭くなるような環状テーパ
面に形成すると共に下端にアール面を形成し、燃焼室の
中央部に、上端面が円錐状の上向き突起部を形成して、
突起部の周側面に突起部中心側にへこむアール面を形成
し、該アール面の下端と内周テーパ面の下端アール面と
を平面状の環状底部を介してつないで、火炎膨脹用底部
空間部を確保し、噴射初期に上記テーパ内周面に燃料を
衝突させるようにし、ピストン下降に従って噴射圧力の
上昇と共に下端空間部に渦流を生じさせるようにした燃
焼室と、 インタークーラからの給気を再度圧縮するコンプレッ
サ部、該コンプレッサ部からの給気を再度冷却するアフ
タークーラ及び該アフタークーラからの給気を膨脹させ
て給気マニホルドに供給すると共に上記コンプレッサ部
を駆動するエアタービン部よりなる給気冷却システムと
を、 備えたことを特徴としている。(Technical Means for Achieving the Object) In order to achieve the above object, the present invention is to suppress the fuel injection rate and the fuel injection pressure in the early stage of combustion near the top dead center, increase in the middle and late stages of combustion, and increase the pressure. The fuel control injection system to be converted to an inner peripheral surface of the combustion chamber is formed into an annular tapered surface having a narrow upper end, and a rounded surface is formed at the lower end. Form an upward projection,
A rounded surface is formed on the peripheral side surface of the projecting portion to be recessed toward the center of the projecting portion, and a lower end of the rounded surface and a lower end rounded surface of the inner peripheral taper surface are connected via a planar annular bottom portion to form a bottom space for flame expansion. And a combustion chamber in which fuel is caused to collide with the inner peripheral surface of the taper at the beginning of the injection, and the injection pressure rises along with the lowering of the piston to generate a vortex in the lower space, and the air supply from the intercooler. A compressor that recompresses the air, an aftercooler that recools the air supplied from the compressor, and an air turbine that expands the air supplied from the aftercooler and supplies the expanded air to the air supply manifold and drives the compressor. And a supply air cooling system.
また出力性能を一層向上させるために、排気タービン
過給機に、低圧段過給機及びプレインタークーラを接続
して2段過給とする。In order to further improve the output performance, a two-stage supercharger is provided by connecting a low-pressure stage supercharger and a pre-intercooler to the exhaust turbine supercharger.
またNOxの低減効果を一層向上させるために、排気の
一部を給気に再循環するEGR装置を付加する。To further improve the NOx reduction effect, an EGR device that recirculates part of the exhaust gas to the air supply is added.
(作用) エアタービン等による給気冷却システムにより給気温
度を0〜5℃に極力低減した状態とし、上死点付近の場
の圧力、温度の高い燃焼初期には、低噴射率及び低噴射
圧による少量噴射を行なうと共に、噴射される噴霧の一
部を内周テーパー面に当てて抑制することにより、初期
噴霧周りの局部高温火炎温度及び量を抑制する。即ち初
期燃焼を抑制し、それによりNOxの生成を抑える。(Operation) The supply air temperature is reduced as much as possible to 0 to 5 ° C. by an air supply cooling system such as an air turbine, and the injection rate and the injection rate are low in the early stage of combustion when the pressure and temperature near the top dead center are high. A small amount of spray by pressure is applied, and a part of the spray to be sprayed is applied to the inner peripheral tapered surface to suppress the temperature and amount of the local high-temperature flame around the initial spray. That is, the initial combustion is suppressed, thereby suppressing the generation of NOx.
ピストンの下降に従い燃料噴射圧を上昇い、火炎はテ
ーパ内周面から平面底部へアールを描きながら中央突起
部側へと流れ、平面底部と突起部のアール面との間に空
間内で膨脹する。この時燃焼室内へ流れる空気の流れは
内周テーパ面と中央突起部の円錐面との作用により噴霧
の衝突後の進出方向と順方向に向う。The fuel injection pressure rises as the piston descends, and the flame flows toward the central projection while drawing a radius from the inner peripheral surface of the taper to the bottom of the plane, and expands in the space between the bottom of the plane and the radius of the projection. . At this time, the flow of the air flowing into the combustion chamber is directed in the forward direction and the forward direction after the collision of the spray by the action of the inner peripheral tapered surface and the conical surface of the central projection.
燃焼中期以降には、高圧噴射により噴射初期の付着し
たテーパ内周面の燃料を飛散させ、またテーパ内周面の
上端部と中央突起部の上端部の間のしぼり部分により火
炎は急速に膨脹して燃焼室の外側へ噴出し、これにより
排気色が改善される。After the middle stage of combustion, high pressure injection scatters fuel on the tapered inner peripheral surface at the beginning of injection, and the flame expands rapidly due to the narrowing between the upper end of the tapered inner peripheral surface and the upper end of the central projection. And then blows out of the combustion chamber, thereby improving the exhaust color.
(実施例) まず燃焼室の形状を説明すると、第1図は本発明を適
用した直接噴射式ディーゼル機関のスキッシュリップ型
燃焼室の断面図を示しており、この第1図において、シ
リンダヘッド2には燃料噴射弁3が少し傾斜した状態で
固定されており、燃料噴射弁3の下端ノズル部はシリン
ダ4の中心線O1から少しずれた位置に位置すると共に、
シリンダ4内に上方から臨んでいる。(Embodiment) First, the shape of a combustion chamber will be described. FIG. 1 is a cross-sectional view of a squish lip type combustion chamber of a direct injection type diesel engine to which the present invention is applied. In FIG. , The fuel injection valve 3 is fixed in a slightly inclined state, the lower end nozzle portion of the fuel injection valve 3 is located at a position slightly shifted from the center line O1 of the cylinder 4,
It faces the cylinder 4 from above.
ピストン1の上壁には、上記燃料噴射弁3のノズル部
から少しシリンダ中心側にずれた中心線O2を中心とする
円盤形の燃焼室5が上端開口状に形成されている。燃焼
室5の環状の内周面7は上端部側が狭くなるようにテー
パー状に形成されており、該テーパー内周面7の下端部
分はアール面8を介して燃焼室底壁9につながってい
る。On the upper wall of the piston 1, a disk-shaped combustion chamber 5 having a center line O2 slightly deviated from the nozzle portion of the fuel injection valve 3 toward the cylinder center is formed in an upper end opening shape. An annular inner peripheral surface 7 of the combustion chamber 5 is formed in a tapered shape so that an upper end portion side is narrowed, and a lower end portion of the tapered inner peripheral surface 7 is connected to a combustion chamber bottom wall 9 via a round surface 8. I have.
燃焼室5の底壁9は平面状に形成されており、燃焼室
5の中央部には底壁9部分から上方に突出するきのこ形
の中央突起部10が形成されており、該突起部10の上端面
10aは燃焼室中心線O2を中心とする緩やかな円錐状に形
成されている。中央突起部10の上端面10aはピストン1
の上端面よりも少し低い位置に形成されている。中央突
起部10の周側面には燃焼室中心側にへこむ環状のアール
面11が形成されており、該アール面11の下端部は滑らか
に上記平面状底部9につながり、両アール面8、11と平
面状底部9とで容積の大きい火炎膨脹用底部空間部Sを
確保している。The bottom wall 9 of the combustion chamber 5 is formed in a planar shape, and a mushroom-shaped central projection 10 projecting upward from the bottom wall 9 is formed at the center of the combustion chamber 5. Top edge of
10a is formed in a gentle conical shape centered on the combustion chamber center line O2. The upper end surface 10a of the central projection 10 is the piston 1
Is formed at a position slightly lower than the upper end surface of. An annular round surface 11 is formed on the peripheral side surface of the central projection 10 so as to be recessed toward the center of the combustion chamber. The lower end of the round surface 11 is smoothly connected to the flat bottom 9, and both round surfaces 8, 11 are formed. The flat bottom 9 secures a large flame expansion bottom space S.
燃料噴射弁3の先端ノズル部には複数の噴口が形成さ
れ、各噴口から噴射される噴霧Pの仮想中心線Aの方向
は概ね突起部上端面と平行になるように設定されてお
り、噴射初期においてテーパー内周面7に低圧力噴霧P
が衝突するようになっている。A plurality of nozzles are formed in the tip nozzle portion of the fuel injection valve 3, and the direction of the virtual center line A of the spray P injected from each nozzle is set so as to be substantially parallel to the upper end surface of the protrusion. Initially, the low pressure spray P is applied to the inner peripheral surface 7 of the taper.
Are to collide.
次に高圧噴射率制御噴射系について説明すると、噴射
カムのカム面の高さ及び形状等の変更により噴射率及び
噴射圧は第5図に示すように設定されている。即ち上死
点付近の噴射初期の間は噴射率及び噴射圧は共に低く抑
えられている。Next, the high-pressure injection rate control injection system will be described. The injection rate and injection pressure are set as shown in FIG. 5 by changing the height and shape of the cam surface of the injection cam. That is, during the initial stage of injection near the top dead center, the injection rate and the injection pressure are both kept low.
噴射中期で噴射率及び噴射圧は増加し、噴射後期にお
いては高圧の噴射圧になると共に噴射率も最大になる。In the middle stage of injection, the injection rate and the injection pressure increase, and in the latter half of the injection, the injection rate becomes high and the injection rate becomes maximum.
第7図はディーゼル機関の全体略図を示しており、機
関20の両側に給気マニホルド21と排気マニホルド22が設
けられ、排気マニホルド22には高圧力比の排気タービン
過給機24のタービン部25が接続されている。タービン部
25とコンプレッサ部26の間には調節バルブ41を介してEG
R(排気ガス再循環)装置42が設けられ、少量(例えば
5〜10%程度)の排気を調節して給気に再循環できるよ
うになっている。FIG. 7 shows an overall schematic view of a diesel engine. An intake manifold 21 and an exhaust manifold 22 are provided on both sides of an engine 20. Is connected. Turbine section
EG via a control valve 41 between 25 and the compressor section 26
An R (exhaust gas recirculation) device 42 is provided so that a small amount (for example, about 5 to 10%) of exhaust gas can be adjusted and recirculated to the supply air.
上記過給機24のコンプレッサ部26には小型のインター
クーラ27が接続し、該インタークーラ27はタービン式の
給気冷却システム30を介して給気マニホルド21に接続し
ている。A small-sized intercooler 27 is connected to the compressor section 26 of the supercharger 24, and the intercooler 27 is connected to the air supply manifold 21 via a turbine-type air supply cooling system 30.
給気冷却システム30内のエア経路中には、上流側から
順に、給気を再度圧縮するためのコンプレッサ部31と、
再度冷却するためのアクタークーラ35と、膨脹により給
気を極低温に下げるためのエアタービン部32と、外部か
ら大気を補充できる補助給気口37が接続されている。コ
ンプレッサ部31とエアタービン部32はタービン軸33を介
して連動連結しており、タービン部32によりコンプレッ
サ部31を駆動するようになっている。補助給気口37には
外部からの大気の導入のみを許す逆止弁38が設けられ、
タービン部32による給気の膨脹により負圧になった時
に、外部から大気を補充する。In the air path in the supply air cooling system 30, in order from the upstream side, a compressor unit 31 for compressing the supply air again,
An actor cooler 35 for re-cooling, an air turbine section 32 for lowering the supply air to an extremely low temperature by expansion, and an auxiliary air supply port 37 for replenishing the atmosphere from the outside are connected. The compressor section 31 and the air turbine section 32 are linked to each other via a turbine shaft 33, and the compressor section 31 is driven by the turbine section 32. The auxiliary air supply port 37 is provided with a check valve 38 that allows only the introduction of air from the outside,
When a negative pressure is caused by expansion of the supply air by the turbine section 32, the atmosphere is externally replenished.
作動を説明する。第7図においてまず給気の流れ及び
その温度変化について説明すると、排気タービン過給機
24のコンプレッサ部26部には、外部から例えば略20℃の
吸気が吸い込まれると共に、排気マニホルド22側からEG
R装置42を介して少量の排気ガスが吸い込まれ、圧縮さ
れる。この圧縮により給気温度は略100℃に上昇する。
またEGR装置42内では排気ガス中のカーボン成分は除去
される。The operation will be described. First, the flow of the supply air and its temperature change will be described with reference to FIG.
Into the compressor part 26 of the compressor 24, for example, intake air at approximately 20 ° C. is sucked from the outside, and the EG is supplied from the exhaust manifold 22 side.
A small amount of exhaust gas is sucked through the R device 42 and compressed. This compression raises the supply air temperature to approximately 100 ° C.
In the EGR device 42, carbon components in the exhaust gas are removed.
コンプレッサ部26で圧縮された給気はインターラ27で
40〜50℃に冷却された後、給気冷却システム30に入る。
給気冷却システム30内ではまずコンプレッサ部31で再圧
縮されて、略100℃まで温度が上昇するが、アフターク
ーラ35で略40℃に冷却され、エアタービン部32において
膨脹する。それにより給気圧力が低下すると同時に極め
て低い温度(0〜5℃)にまで給気温度は低下し、給気
マニホルド21に供給される。The air supply compressed by the compressor section 26
After cooling to 40-50 ° C., it enters the charge air cooling system 30.
In the air supply cooling system 30, the air is first recompressed by the compressor unit 31 and the temperature rises to approximately 100 ° C., but is cooled to approximately 40 ° C. by the after cooler 35 and expanded in the air turbine unit 32. As a result, at the same time as the supply pressure decreases, the supply temperature decreases to an extremely low temperature (0 to 5 ° C.) and is supplied to the supply manifold 21.
次に燃焼室内における変化を説明する。第1図のよう
に上死点近辺における噴射初期においては、弱い噴射圧
で噴射される燃料噴霧Pは、テーパ内周面7に衝突し、
一部がテーパ内周面7に付着すると共に、残りはテーパ
内周面に沿って流れ、また前述のように給気温度が極低
温になっていることにより、急激な燃焼が抑制され、NO
xの発生量が低下する。Next, changes in the combustion chamber will be described. In the initial stage of injection near the top dead center as shown in FIG. 1, the fuel spray P injected at a low injection pressure collides with the tapered inner peripheral surface 7,
A part of the gas adheres to the tapered inner peripheral surface 7 and the other flows along the tapered inner peripheral surface. Further, since the supply air temperature is extremely low as described above, rapid combustion is suppressed and NO
The generation amount of x decreases.
第2図のようにクランク角10゜付近までピストンが下
降すると、燃料噴射圧は上昇し、火炎はテーパ内周面7
から平面状底部9へとアール面8によりアールを描き、
底部空間部(膨脹室)S内で膨脹しながら突起部10のア
ール面11へと流れる。そして継続して噴射される噴霧と
共に底部空間部(膨脹室)Sで渦状の火炎流動を形成す
る。As shown in FIG. 2, when the piston descends to a crank angle of about 10 °, the fuel injection pressure rises, and the flame spreads on the tapered inner peripheral surface 7.
Draw a radius from the radius surface 8 to the flat bottom 9 from
While expanding in the bottom space (expansion chamber) S, it flows to the round surface 11 of the projection 10. A spiral flame flow is formed in the bottom space (expansion chamber) S together with the spray continuously sprayed.
第3図(クランク角20゜付近)のように燃焼中期以降
は、高圧噴射により噴射初期の付着したテーパ内周面の
燃料を飛散させ、またテーパ内周面7の上端部と中央突
起部10の上端部の間のしぼり部分により火炎は急速に膨
脹して強いスキッシュ流として燃焼室5の外側へ噴出
し、排気色が改善される。As shown in FIG. 3 (around the crank angle of 20 °), after the middle stage of combustion, the fuel on the tapered inner peripheral surface attached at the initial stage of injection is scattered by high-pressure injection, and the upper end of the tapered inner peripheral surface 7 and the central projection 10 The flame expands rapidly due to the squeezed portion between the upper ends of the fuel cells and blows out of the combustion chamber 5 as a strong squish flow, so that the exhaust color is improved.
第6図は排気色並びにNOxの発生量の変化を示すグラ
フであり、実線で示すグラフA1は従来例、一点鎖線で示
すグラフA3は本発明による第1図の燃焼室、第8図の高
圧噴射率制御噴射系並びに第7図の給気冷却システム及
びEGR装置を備えた場合の変化を示している。また破線
で示すグラフA2は、グラフA3の上記条件からEGR装置を
外した場合の変化を示している。FIG. 6 is a graph showing changes in the exhaust color and the amount of generated NOx. A graph A1 shown by a solid line is a conventional example, a graph A3 shown by a dashed line is a combustion chamber of FIG. 1 according to the present invention, and a high pressure of FIG. 9 shows changes when the injection rate control injection system, the air supply cooling system and the EGR device shown in FIG. 7 are provided. A graph A2 indicated by a broken line shows a change when the EGR device is removed from the above condition of the graph A3.
(別の実施例) (1)第4図の仮想線で示すようにEGR装置42を給気マ
ニホルド21と排気マニホルド22の間に直接架け渡す構造
でもよい。(Another embodiment) (1) As shown by the phantom line in FIG. 4, the EGR device 42 may be directly bridged between the air supply manifold 21 and the exhaust manifold 22.
(2)第7図は請求項2記載の2段過給方式を適用した
例であり、高圧段用の排気タービン過給機24に低圧段過
給機50を付加している。両過給機24、50のタービン部5
1、25同志が排気管55を介して接続し、コンプレッサ部5
2、26同志がプレインタークーラ53を介して接続してい
る。(2) FIG. 7 shows an example in which the two-stage supercharging method according to claim 2 is applied, in which a low-pressure stage supercharger 50 is added to the high-pressure stage exhaust turbine supercharger 24. Turbine section 5 of both turbochargers 24, 50
1 and 25 are connected via exhaust pipe 55, and compressor section 5
2, 26 comrades are connected via the pre-intercooler 53.
これによると過給圧の増大により給気の圧力比を上
げ、給気冷却システム30のエアタービン部32の膨脹比を
増大させて、極低温の給気の流量を増大させ、出力性能
を一層向上させることができる。According to this, the pressure ratio of the air supply is increased by increasing the supercharging pressure, the expansion ratio of the air turbine unit 32 of the air supply cooling system 30 is increased, the flow rate of the cryogenic air supply is increased, and the output performance is further improved. Can be improved.
また低圧段過給機50のタービン部51の入口にスクロー
ル切換え弁60を取り付けて、タービン部51に入る排気の
流通断面積を可変とすることもできる。即ちセンサー等
により、給気マニホルド21の給気圧が低い時あるいは給
気温度が高い時等を検知して、図示のようにスクロール
弁60で排気管55を半分閉じることにより、排気の流速を
上げてタービン回転を増大させ、給気量不足を補う。Further, a scroll switching valve 60 may be attached to the inlet of the turbine unit 51 of the low-pressure stage turbocharger 50 so that the cross-sectional area of exhaust gas flowing into the turbine unit 51 can be made variable. That is, a sensor or the like detects when the supply pressure of the supply manifold 21 is low or when the supply temperature is high, etc., and closes the exhaust pipe 55 halfway with the scroll valve 60 as shown to increase the flow rate of exhaust gas. To increase the turbine rotation to compensate for the shortage of air supply.
(3)第8図は2段過給方式を採用すると同時にEGR装
置42も取り付けた例である。EGR装置42は低圧段過給機5
0のタービン部51とコンプレッサ部52の間に取り付けら
れているが、仮想線で示すように給気マニホルド21と排
気マニホルド22の間に直接設けることも可能である。(3) FIG. 8 shows an example in which the two-stage supercharging method is adopted and the EGR device 42 is also attached. The EGR device 42 is a low-pressure stage turbocharger 5
Although it is attached between the turbine section 51 and the compressor section 52, it can also be provided directly between the supply manifold 21 and the exhaust manifold 22 as shown by a virtual line.
(発明の効果) 以上説明したように本発明によると: (1)噴射初期においては高圧噴射率制御噴射系によっ
て噴射圧及び噴射率が低く抑えられると共に、燃焼室内
において噴霧Pがテーパー内周面7に衝突し、しかも燃
焼の場は給気冷却システム30によって極低温にされてい
るので、確実な着火と共に初期燃焼が抑制され、それに
よりNOxの生成量を減少させることができる。(Effects of the Invention) As described above, according to the present invention: (1) In the initial stage of injection, the injection pressure and the injection rate are suppressed low by the high-pressure injection rate control injection system, and the spray P is formed into the tapered inner peripheral surface in the combustion chamber. 7 and the combustion field is cryogenically cooled by the charge air cooling system 30, so that the initial combustion is suppressed together with the reliable ignition, thereby reducing the NOx generation.
(2)ピストン1の下降に従って燃料噴射圧は上昇し、
火炎はテーパ内周面7から平面状底部9へとアール面8
によりアールを描き、底部空間部(膨脹室)S内で膨脹
しながら突起部10のアール面11へと流れる。そして継続
して噴射される噴霧と共に底部空間部(膨脹室)Sで渦
状の火炎流動を形成する。(2) As the piston 1 descends, the fuel injection pressure increases,
The flame is rounded 8 from the tapered inner peripheral surface 7 to the flat bottom 9.
, And flows to the round surface 11 of the projection 10 while expanding in the bottom space (expansion chamber) S. A spiral flame flow is formed in the bottom space (expansion chamber) S together with the spray continuously sprayed.
そして燃焼中期以降は、高圧噴射により噴射初期の付
着したテーパ内周面7の燃料を飛散させ、またテーパ内
周面7の上端部と中央突起部10の上端部の間のしぼり部
分により火炎は急速に膨脹して強いスキッシュ流れとし
て燃焼室5の外側へ噴出し、排気色が改善される。After the middle stage of combustion, the fuel on the tapered inner peripheral surface 7 attached at the initial stage of the injection is scattered by the high pressure injection, and the flame is formed by the narrowed portion between the upper end of the tapered inner peripheral surface 7 and the upper end of the central projection 10. It expands rapidly and blows out of the combustion chamber 5 as a strong squish flow, so that the exhaust color is improved.
(3)排気タービン過給機24に低圧段過給機50を付加し
て2段過給とすることにより、過給圧の増大により給気
の圧力比を上げ、給気冷却システム30のエアタービン部
32の膨脹比を増大させることができる。従って極低温の
給気の流量を増大させ、出力性能を一層向上させること
ができる。(3) By adding a low-pressure stage supercharger 50 to the exhaust turbine supercharger 24 to achieve two-stage supercharging, the pressure ratio of the air supply is increased by increasing the supercharging pressure, and the air of the air supply cooling system 30 is increased. Turbine section
The expansion ratio of 32 can be increased. Therefore, the flow rate of the cryogenic air supply can be increased, and the output performance can be further improved.
(4)EGR装置を付加することにより、酸素濃度を低下
させ、燃焼を緩慢にできるので、NOxの発生量は一層低
減する。(4) By adding an EGR device, the oxygen concentration can be reduced and combustion can be slowed, so that the amount of generated NOx is further reduced.
第1図は本発明を適用したディーゼル機関の燃焼室であ
って、噴射初期の状態を示す縦断面図、第2図〜第3図
はクランク角の増加に従った噴射状態の変化を順次示す
縦断面図、第4図はディーゼル機関の全体略図、第5図
は筒内圧、噴射圧、噴射率、平均ガス温度及び熱発生率
の変化を示すグラフ、第6図はNOxの変化並びに排気色
の変化を示すグラフ、第7図は2段過給方式を採用した
ディーゼル機関の全体略図、第8図は2段過給方式及び
EGR装置を採用したディーゼル機関の全体略図、第9図
及び第10図は従来例の燃焼室の縦断面略図、第11図は従
来例のディーゼル機関の全体略図、第12図は従来の燃料
制御噴射系による噴射圧及び噴射率のグラフである。1
……ピストン、2……シリンダヘッド、3……燃料噴射
弁、4……シリンダ、5……燃焼室、7……テーパー内
周面、8……アール面、9……平面状底部、10……中央
突起部、11……アール面、24……排気タービン過給機、
27……インタークーラ、30……給気冷却システム、31…
…アフタークーラ、32……膨脹用エアタービン、42……
EGR装置、50……低圧段過給機、53……プレインターク
ーラFIG. 1 is a longitudinal sectional view showing a combustion chamber of a diesel engine to which the present invention is applied, showing an initial injection state, and FIGS. 2 and 3 sequentially show changes in the injection state with an increase in crank angle. FIG. 4 is a vertical sectional view, FIG. 4 is a general schematic view of a diesel engine, FIG. 5 is a graph showing changes in in-cylinder pressure, injection pressure, injection rate, average gas temperature and heat generation rate, and FIG. 6 is a change in NOx and exhaust color. FIG. 7 is a general schematic view of a diesel engine employing a two-stage supercharging system, and FIG.
9 and 10 are vertical cross-sectional schematic views of a conventional combustion chamber, FIG. 11 is a general schematic view of a conventional diesel engine, and FIG. 12 is a conventional fuel control system. It is a graph of injection pressure and injection rate by an injection system. 1
...... Piston, 2 ... Cylinder head, 3 ... Fuel injection valve, 4 ... Cylinder, 5 ... Combustion chamber, 7 ... Taper inner peripheral surface, 8 ... R surface, 9 ... Planar bottom portion, 10 …… Central protrusion, 11 …… Round surface, 24 …… Exhaust turbine supercharger,
27 ... Intercooler, 30 ... Air supply cooling system, 31 ...
… Aftercooler, 32 …… Inflation air turbine, 42 ……
EGR device, 50 …… Low pressure supercharger, 53 …… Pre-intercooler
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 FI F02D 43/00 301 F02D 43/00 301G F02M 25/07 570 F02M 25/07 570D 570P (72)発明者 吉川 滋 大阪府大阪市北区茶屋町1番32号 ヤン マーディーゼル株式会社内 (56)参考文献 特開 昭57−108424(JP,A) 特開 昭49−93717(JP,A) 実開 平3−87928(JP,U) 実開 昭61−155636(JP,U)──────────────────────────────────────────────────の Continuation of front page (51) Int.Cl. 6 Identification code FI F02D 43/00 301 F02D 43/00 301G F02M 25/07 570 F02M 25/07 570D 570P (72) Inventor Shigeru Yoshikawa Osaka-shi, Osaka 1-32 Chayama-cho, Kita-ku Inside Yanmar Diesel Co., Ltd. (56) References JP-A-57-108424 (JP, A) JP-A-49-93717 (JP, A) JP-A-3-87928 (JP, A) U) Japanese Utility Model Showa 61-155636 (JP, U)
Claims (3)
備え、ピストン上壁に形成した燃焼室に燃料噴射弁から
直接燃料を噴射する直接噴射式内燃機関において、 燃料噴射率及び燃料噴射圧を、上死点付近の燃焼初期で
抑制し、燃焼中期、後期で増大、高圧化させる高圧噴射
率制御噴射系と、 燃焼室の内周面を上端部が狭くなるような環状テーパ面
に形成すると共に下端にアール面を形成し、燃焼室の中
央部に、上端面が円錐状の上向き突起部を形成して、突
起部の周側面に突起部中心側にへこむアール面を形成
し、該アール面の下端と内周テーパ面の下端アール面と
を平面状の環状底部を介してつないで、火炎膨脹用底部
空間部を確保し、噴射初期に上記テーパ内周面に燃料を
衝突させるようにし、ピストン下降に従って噴射圧力の
上昇と共に下端空間部に渦流を生じさせるようにした燃
焼室と、 前記インタークーラからの給気を再度圧縮するコンプレ
ッサ部、該コンプレッサ部からの給気を再度冷却するア
フタークーラ及び該アフタークーラからの給気を膨脹さ
せて給気マニホルドに供給すると共に上記コンプレッサ
部を駆動するエアタービン部よりなる給気冷却システム
とを、 備えたことを特徴とする直接噴射式内燃機関。A direct injection type internal combustion engine having an exhaust turbine supercharger and an intercooler, wherein fuel is directly injected from a fuel injection valve into a combustion chamber formed on an upper wall of a piston. A high-pressure injection rate control injection system that suppresses at the early stage of combustion near the top dead center and increases and increases the pressure in the middle and late stages of combustion, and the inner peripheral surface of the combustion chamber is formed as an annular tapered surface with a narrow upper end. A rounded surface is formed at a lower end, an upper end surface forms a conical upward protruding portion at a central portion of the combustion chamber, and a rounded surface is formed on a peripheral side surface of the protruding portion so as to be recessed toward the center of the protruding portion. By connecting the lower end of the inner peripheral taper surface and the lower end round surface of the inner peripheral taper surface through a planar annular bottom portion, a flame expansion bottom space portion is secured, and fuel is caused to collide with the taper inner peripheral surface at the beginning of injection. Injection pressure rises with piston down A combustion chamber for generating a vortex in the lower end space, a compressor section for compressing the air supply from the intercooler again, an aftercooler for cooling the air supply from the compressor section again, and a supply from the aftercooler. A direct-injection type internal combustion engine, comprising: a supply air cooling system including an air turbine unit that expands air and supplies the air to an intake manifold and drives the compressor unit.
て、排気タービン過給機に、低圧段過給機及びプレイン
タークーラを接続して2段過給としたことを特徴とする
直接噴射式内燃機関。2. A direct injection type internal combustion engine according to claim 1, wherein a low pressure stage supercharger and a pre-intercooler are connected to the exhaust turbine supercharger to perform two-stage supercharging. Type internal combustion engine.
て、排気の一部を給気に再循環するEGR装置を付加した
ことを特徴とする直接噴射式内燃機関。3. The direct injection type internal combustion engine according to claim 1, further comprising an EGR device for recirculating a part of exhaust gas to supply air.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2134755A JP2759375B2 (en) | 1990-05-24 | 1990-05-24 | Direct injection internal combustion engine |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2134755A JP2759375B2 (en) | 1990-05-24 | 1990-05-24 | Direct injection internal combustion engine |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH0431653A JPH0431653A (en) | 1992-02-03 |
JP2759375B2 true JP2759375B2 (en) | 1998-05-28 |
Family
ID=15135808
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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JP2134755A Expired - Lifetime JP2759375B2 (en) | 1990-05-24 | 1990-05-24 | Direct injection internal combustion engine |
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008291680A (en) * | 2007-05-22 | 2008-12-04 | Yanmar Co Ltd | Electronic governor control engine |
US9121336B2 (en) | 2011-07-18 | 2015-09-01 | Hyundai Motor Company | Diesel engine piston |
US20220235717A1 (en) * | 2021-01-28 | 2022-07-28 | Southwest Research Institute | Internal Combustion Engine with Cooling Assist System for Manifold Intake Temperature Reduction |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0458015A (en) * | 1990-06-28 | 1992-02-25 | Shinnenshiyou Syst Kenkyusho:Kk | Combustion chamber of direct injection type diesel engine |
US8215292B2 (en) * | 1996-07-17 | 2012-07-10 | Bryant Clyde C | Internal combustion engine and working cycle |
JP4595273B2 (en) * | 2001-09-26 | 2010-12-08 | マツダ株式会社 | Diesel engine fuel combustion system |
JP6391027B2 (en) * | 2013-06-05 | 2018-09-19 | ファーランティ,フラビオ | Engine charge system |
-
1990
- 1990-05-24 JP JP2134755A patent/JP2759375B2/en not_active Expired - Lifetime
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008291680A (en) * | 2007-05-22 | 2008-12-04 | Yanmar Co Ltd | Electronic governor control engine |
US9121336B2 (en) | 2011-07-18 | 2015-09-01 | Hyundai Motor Company | Diesel engine piston |
US20220235717A1 (en) * | 2021-01-28 | 2022-07-28 | Southwest Research Institute | Internal Combustion Engine with Cooling Assist System for Manifold Intake Temperature Reduction |
US11459939B2 (en) * | 2021-01-28 | 2022-10-04 | Southwest Research Institute | Internal combustion engine with cooling assist system for manifold intake temperature reduction |
Also Published As
Publication number | Publication date |
---|---|
JPH0431653A (en) | 1992-02-03 |
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