JP2005180234A - Engine system - Google Patents

Engine system Download PDF

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JP2005180234A
JP2005180234A JP2003419247A JP2003419247A JP2005180234A JP 2005180234 A JP2005180234 A JP 2005180234A JP 2003419247 A JP2003419247 A JP 2003419247A JP 2003419247 A JP2003419247 A JP 2003419247A JP 2005180234 A JP2005180234 A JP 2005180234A
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engine
injection pressure
amount
intake
opening
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Ichiro Tsumagari
一郎 津曲
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Hino Motors Ltd
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Hino Motors Ltd
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    • 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
    • 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
    • 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
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
    • F02M26/23—Layout, e.g. schematics
    • 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
    • F02M26/45—Sensors specially adapted for EGR systems
    • F02M26/46—Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition
    • F02M26/47—Sensors specially adapted for EGR systems for determining the characteristics of gases, e.g. composition the characteristics being temperatures, pressures or flow rates

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Exhaust-Gas Circulating Devices (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To prevent increase of NOx emission even at a time of transient operation of a diesel engine. <P>SOLUTION: In an engine system provided with a variable capacity turbo 1 supercharging intake air and feeding the same to a combustion chamber of the engine 2 and EGR device 12 re-circulating a part of exhaust gas from the engine 2 to an intake side, command injection pressure P of fuel injected to the combustion chamber of the engine 2 is controlled based on change quantity of opening of EGR valve 13 in EGR device 12. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、可変容量ターボ及びＥＧＲ装置を用いたディーゼルエンジンを急加速或は急減速するような過渡時にも、排ガス中に含まれる窒素酸化物（ＮＯｘ）の排出量を低減させ得るようにしたエンジンシステムに関するものである。   The present invention has made it possible to reduce the emission of nitrogen oxides (NOx) contained in exhaust gas even during a transient such as sudden acceleration or deceleration of a diesel engine using a variable capacity turbo and EGR device. It relates to the engine system.

ディーゼルエンジンにおいては、エンジンからの排ガスの一部を吸気と共にエンジン燃焼室に供給し、燃料の燃焼温度を押えて窒素酸化物（ＮＯｘ）の生成を抑制するようにしたＥＧＲ装置が用いられている。   In a diesel engine, an EGR device is used in which a part of exhaust gas from an engine is supplied to an engine combustion chamber together with intake air to suppress the generation of nitrogen oxides (NOx) by suppressing the combustion temperature of the fuel. .

斯かるＥＧＲ装置では、例えば急加速時のように燃料噴射量を急に増大させるような過渡時には、黒煙が発生する現象があることが知られている。このように過渡時に黒煙が発生するのは、エンジン回転が急上昇すると、排気管の内圧が上昇するが、吸気管の内圧の上昇が遅れるため、排気管からＥＧＲバルブを介して吸気側に排ガスが大量に還流し、燃焼状態が悪化するからであると考えられている。   In such an EGR device, for example, it is known that there is a phenomenon in which black smoke is generated in a transient state in which the fuel injection amount is suddenly increased, for example, during rapid acceleration. As described above, black smoke is generated during a transition because when the engine speed rises rapidly, the internal pressure of the exhaust pipe rises, but since the rise of the internal pressure of the intake pipe is delayed, the exhaust gas is exhausted from the exhaust pipe to the intake side via the EGR valve. It is thought that this is because a large amount of gas is recirculated and the combustion state deteriorates.

そこで、過渡時に黒煙を減少させるために、吸気量や過給圧等を用いて、フィードバック制御によりＥＧＲバルブを閉止し、吸気側に還流される排ガスの量を減少させることが行われている。   Therefore, in order to reduce black smoke during the transition, the EGR valve is closed by feedback control using the intake air amount, the supercharging pressure, etc., and the amount of exhaust gas recirculated to the intake side is reduced. .

又、排ガス中のＮＯｘを減少させるようにしたものとしては、特許文献１があり、黒煙やＮＯｘを低減するためのものとしては、特許文献２、３がある。
特開２００１−１２３８５８号公報 特開２００３−２１０００号公報 特開２００１−３７９６号公報 Further, Patent Document 1 is provided to reduce NOx in exhaust gas, and Patent Documents 2 and 3 are provided to reduce black smoke and NOx.
JP 2001-123858 A JP 2003-21000 A JP 2001-3796 A

しかしながら、上述のごとく、過渡時に黒煙を減少させるために、吸気量や過給圧等を用いて、フィードバック制御によりＥＧＲバルブを閉止し、吸気側に還流される排ガスの量を減少させる場合には、還流される排ガスの減少に対応して吸気量が増大するため、燃焼状態は良くなるが、燃料の燃焼温度が上昇し、逆にＮＯｘの発生量が増加してしまう。   However, as described above, when reducing the amount of exhaust gas recirculated to the intake side by closing the EGR valve by feedback control using intake air amount, supercharging pressure, etc., in order to reduce black smoke at the time of transition. Since the intake air amount increases corresponding to the reduction of the exhaust gas being recirculated, the combustion state is improved, but the combustion temperature of the fuel rises, and on the contrary, the amount of NOx generated increases.

又、特許文献１、２、３はＮＯｘや黒煙を減少させるようにしてはいるが、手段が異なり、本件とは直接的な関連性はない。   Patent Documents 1, 2, and 3 attempt to reduce NOx and black smoke, but the means are different and are not directly related to this case.

本発明は、斯かる実情に鑑み、ディーゼルエンジンの過渡運転時にも、ＮＯｘの発生が増大するのを防止し得るようにしたエンジンシステムを提供することを目的としてなしたものである。   The present invention has been made in view of such circumstances, and an object of the present invention is to provide an engine system capable of preventing an increase in the generation of NOx even during a transient operation of a diesel engine.

請求項１の発明は、吸気を過給してエンジンの燃焼室に送給するための可変容量ターボと、前記エンジンからの排ガスの一部を吸気側に還流するＥＧＲ装置を備えたエンジンシステムにおいて、前記ＥＧＲ装置におけるＥＧＲバルブの開度の変化量、若しくは吸気側の不足吸気量を基に、前記エンジンの燃焼室に噴射される燃料の噴射圧を制御するようにした手段を設けたものである。   The invention of claim 1 is an engine system comprising a variable capacity turbocharger for supercharging intake air and supplying it to a combustion chamber of the engine, and an EGR device for recirculating a part of exhaust gas from the engine to the intake side. And means for controlling the injection pressure of the fuel injected into the combustion chamber of the engine based on the amount of change in the opening of the EGR valve in the EGR device or the insufficient intake amount on the intake side. is there.

請求項２の発明は、吸気を過給してエンジンの燃焼室に送給するための可変容量ターボと、前記エンジンからの排ガスの一部を吸気側に還流するＥＧＲ装置を備えたエンジンシステムにおいて、加速時には、前記ＥＧＲ装置におけるＥＧＲバルブの開度の変化量、若しくは吸気側の不足吸気量を基に、前記エンジンの燃焼室に噴射される燃料の噴射圧を減少させるように制御する手段を設けたものである。   According to a second aspect of the present invention, there is provided an engine system including a variable capacity turbocharger for supercharging intake air and supplying it to a combustion chamber of the engine, and an EGR device for recirculating a part of exhaust gas from the engine to the intake side. And means for controlling to reduce the injection pressure of the fuel injected into the combustion chamber of the engine based on the amount of change in the opening of the EGR valve in the EGR device or the insufficient intake amount on the intake side during acceleration. It is provided.

本発明のエンジンシステムによれば、エンジンの過渡運転時にも、ＮＯｘの発生が増大することを防止することができ、排ガスの性能を向上させることができる、という優れた効果を奏し得る。   According to the engine system of the present invention, it is possible to prevent an increase in the generation of NOx even during the transient operation of the engine, and to obtain an excellent effect that the performance of exhaust gas can be improved.

以下、本発明の実施の形態を図示例と共に説明する。
図１〜図１８は本発明を実施する形態の一例である。
図１に可変容量ターボ１を備えたディーゼルエンジン２を示す。エンジン２の吸気ポート３には、吸気マニホールド４を介して吸気管５が接続され、排気ポート６には排気マニホールド７を介して排気管８が接続されている。吸気管５には吸気を冷却するためのインタクーラ９が設けられている。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 18 are examples of embodiments for carrying out the present invention.
FIG. 1 shows a diesel engine 2 equipped with a variable displacement turbo 1. An intake pipe 5 is connected to the intake port 3 of the engine 2 via an intake manifold 4, and an exhaust pipe 8 is connected to the exhaust port 6 via an exhaust manifold 7. The intake pipe 5 is provided with an intercooler 9 for cooling the intake air.

可変容量ターボ１は、吸気管５に設けられたコンプレッサ１ａと、排気管８に設けられたタービン１ｂを備えており、タービン１ｂの駆動によりコンプレッサ１ａを駆動し得るようになっている。又、タービン１ｂはエアシリンダ又はサーボモータ等により駆動されて可変静翼の角度を調整するようにした容量可変手段１０を備えている。   The variable displacement turbo 1 includes a compressor 1a provided in the intake pipe 5 and a turbine 1b provided in the exhaust pipe 8, and the compressor 1a can be driven by driving the turbine 1b. Further, the turbine 1b is provided with a variable capacity means 10 which is driven by an air cylinder or a servo motor to adjust the angle of the variable stationary blade.

エンジン２には排気マニホールド７内の排ガスの一部をＥＧＲパイプ１１を介して吸気マニホールド４へ還流させるＥＧＲ装置１２が設けられている。ＥＧＲ装置１２は、一端が排気マニホールド７に接続され、他端が吸気マニホールド４に接続された前記ＥＧＲパイプ１１と、ＥＧＲパイプ１１に設けられて排気マニホールド７からＥＧＲパイプ１１を通って吸気マニホールド４に還流される排ガスの流量を調整するようにしたＥＧＲバルブ１３と、同様にＥＧＲパイプ１１に設けられて吸気マニホールド４へ還流される排ガス（ＥＧＲガス）を冷却するようにしたＥＧＲクーラ１４を備えている。   The engine 2 is provided with an EGR device 12 that recirculates a part of the exhaust gas in the exhaust manifold 7 to the intake manifold 4 via the EGR pipe 11. The EGR device 12 has one end connected to the exhaust manifold 7 and the other end connected to the intake manifold 4. The EGR device 12 is provided in the EGR pipe 11 and is provided from the exhaust manifold 7 through the EGR pipe 11 to the intake manifold 4. An EGR valve 13 that adjusts the flow rate of the exhaust gas recirculated to the exhaust gas, and an EGR cooler 14 that is similarly provided in the EGR pipe 11 and cools the exhaust gas recirculated to the intake manifold 4 (EGR gas). ing.

又、図中、１５は燃料噴射ポンプ、１６は蓄圧式噴射装置（コモンレール）、１７はエンジン２の回転数（エンジン回転数Ｎ）を検出するための回転センサ、１８は踏込まれたアクセルの開度（アクセル開度Ａｃ）を検出するアクセル開度センサ、１９は吸気管５のコンプレッサ１ａよりも上流側に接続されて実吸気量Ｆを検出するための流量センサ、２０は吸気管５のコンプレッサ１ａ下流側に設けられて、吸気の過給圧Ｐｂを検出するための吸気圧センサであり、各センサで検出した出力は演算制御装置２１に与え得るようになっている。   In the figure, 15 is a fuel injection pump, 16 is an accumulator (common rail), 17 is a rotation sensor for detecting the rotational speed of the engine 2 (engine rotational speed N), and 18 is the opening of the depressed accelerator. Accelerator opening sensor 19 for detecting the degree (accelerator opening Ac), 19 is a flow sensor for detecting the actual intake air amount F connected upstream of the compressor 1a of the intake pipe 5, and 20 is a compressor for the intake pipe 5. An intake pressure sensor is provided on the downstream side of 1a for detecting the boost pressure Pb of intake air, and the output detected by each sensor can be given to the arithmetic and control unit 21.

又、演算制御装置２１からは、指令として、ＥＧＲバルブ１３に総補正開度Ｄｅを与え得るようになっており、タービン１ｂの容量可変手段１０に総補正開度Ｄｔを与え得るようになっており、燃料噴射ポンプ１５の圧力制御弁に指示噴射圧Ｐを与え得るようになっており、燃料噴射ポンプ１５の流量制御弁に燃料噴射量Ｑを与え得るようになっている。   Further, the arithmetic control unit 21 can give the total correction opening De to the EGR valve 13 as a command, and can give the total correction opening Dt to the capacity varying means 10 of the turbine 1b. The command injection pressure P can be applied to the pressure control valve of the fuel injection pump 15, and the fuel injection amount Q can be applied to the flow control valve of the fuel injection pump 15.

演算制御装置２１は、図２に示すように、吸気量偏差算出部２２、補正開度算出部２３、補正噴射圧決定部２４、指示噴射圧算出部２５を備えている。又、演算制御装置２１には各種マップが記憶されている。   As shown in FIG. 2, the arithmetic control device 21 includes an intake air amount deviation calculation unit 22, a correction opening degree calculation unit 23, a correction injection pressure determination unit 24, and an instruction injection pressure calculation unit 25. Various maps are stored in the arithmetic and control unit 21.

次に、上記図示例の作動を説明する。
車両の走行時には、回転センサ１７で検出したエンジン回転数Ｎ、アクセル開度センサ１８で検出したアクセル開度Ａｃ、流量センサ１９で検出した実吸気量Ｆ、吸気センサ２０で検出した過給圧Ｐｂは、演算制御装置２１へ与えられる。 Next, the operation of the illustrated example will be described.
When the vehicle is traveling, the engine speed N detected by the rotation sensor 17, the accelerator opening Ac detected by the accelerator opening sensor 18, the actual intake air amount F detected by the flow sensor 19, and the supercharging pressure Pb detected by the intake sensor 20 Is given to the arithmetic and control unit 21.

演算制御装置２１では、エンジン回転数Ｎ及びアクセル開度Ａｃから、図６に示すマップを基に燃料噴射量Ｑが求められ、求められた燃料噴射量Ｑは吸気量偏差算出部２２、補正開度算出部２３、指示噴射圧算出部２５へ与えられる。又、エンジン回転数Ｎは、吸気量偏差算出部２２、補正開度算出部２３、補正噴射圧決定部２４、指示噴射圧算出部２５へ与えられ、実吸気量Ｆは吸気量偏差算出部２２へ与えられ、過給圧Ｐｂは、補正開度算出部２３へ与えられる。   In the arithmetic and control unit 21, the fuel injection amount Q is obtained from the engine speed N and the accelerator opening degree Ac based on the map shown in FIG. This is given to the degree calculation unit 23 and the command injection pressure calculation unit 25. The engine speed N is given to the intake air amount deviation calculating unit 22, the corrected opening degree calculating unit 23, the corrected injection pressure determining unit 24, and the commanded injection pressure calculating unit 25, and the actual intake air amount F is the intake air amount deviation calculating unit 22. The boost pressure Pb is given to the corrected opening degree calculation unit 23.

吸気量偏差算出部２２では、エンジン回転数Ｎ及び燃料噴射量Ｑから、図７に示すマップを基に目標吸気量Ｆｏを求め、目標吸気量Ｆｏから流量センサ１９からの実吸気量Ｆを差引いて吸気量偏差ΔＦを求める（ΔＦ＝Ｆｏ−Ｆ）。求めた吸気量偏差ΔＦは補正開度算出部２３へ与えられる。   The intake air amount deviation calculation unit 22 obtains the target intake air amount Fo from the engine speed N and the fuel injection amount Q based on the map shown in FIG. 7, and subtracts the actual intake air amount F from the flow sensor 19 from the target intake air amount Fo. Thus, an intake air amount deviation ΔF is obtained (ΔF = Fo−F). The obtained intake air amount deviation ΔF is given to the corrected opening degree calculation unit 23.

補正開度算出部２３では、エンジン回転数Ｎ及び燃料噴射量Ｑから、図８に示すマップを基にＥＧＲバルブ１３の基本開度Ｄｏが求められると共に、吸気量偏差ΔＦを基に、図９に示すマップを基にＥＧＲバルブ１３の補正開度Ｄ１が求められ、又、エンジン回転数Ｎ及び燃料噴射量Ｑの時間的変化量ΔＱから、図１０に示すマップを基にＥＧＲバルブ１３の補正開度Ｄ２が求められ、基本開度Ｄｏ及び補正開度Ｄ１，Ｄ２を合計して総補正開度Ｄｅが求められる（Ｄｅ＝Ｄｏ＋Ｄ１＋Ｄ２）。ここで、燃料噴射量Ｑの時間的変化量ΔＱは、ある時間と、その時間から僅かに異なる時間との間における燃料噴射量の差として求められる。補正開度算出部２３で求められた総補正開度ＤｅはＥＧＲバルブ１３に与えられてその開度が補正されると共に、補正噴射圧決定部２４へ与えられる。   The correction opening calculation unit 23 obtains the basic opening Do of the EGR valve 13 from the engine speed N and the fuel injection amount Q based on the map shown in FIG. 8, and based on the intake air amount deviation ΔF, FIG. The correction opening degree D1 of the EGR valve 13 is obtained on the basis of the map shown in FIG. 10, and the correction of the EGR valve 13 is made on the basis of the map shown in FIG. 10 from the time variation ΔQ of the engine speed N and the fuel injection amount Q. The opening degree D2 is obtained, and the total opening degree De is obtained by adding the basic opening degree Do and the correction opening degrees D1 and D2 (De = Do + D1 + D2). Here, the temporal change amount ΔQ of the fuel injection amount Q is obtained as a difference in the fuel injection amount between a certain time and a time slightly different from that time. The total corrected opening De obtained by the corrected opening calculation unit 23 is given to the EGR valve 13 so that the opening is corrected and also given to the corrected injection pressure determining unit 24.

本図示例では、補正開度Ｄ２は、燃料噴射量Ｑの時間的変化量ΔＱから求める場合について説明したが、アクセル開度Ａｃの時間的変化量から求めるようにしても良い。又、図１０のマップにより補正開度Ｄ２が求められるのは、エンジン２が加速或は減速の過渡時の時であり、定速走行時には、補正開度Ｄ２は零となる。   In the illustrated example, the correction opening degree D2 has been described as being obtained from the temporal change amount ΔQ of the fuel injection amount Q, but may be obtained from the temporal change amount of the accelerator opening degree Ac. Further, the correction opening degree D2 is obtained from the map of FIG. 10 when the engine 2 is in a transition of acceleration or deceleration, and the correction opening degree D2 becomes zero when traveling at a constant speed.

又、補正開度算出部２３においては、例えば燃料噴射量Ｑの時間的変化率ΔＱ等を基に急加速と判断された場合には、図３〜図５のフローに従って演算が行われ、最終ＥＧＲＶ開度（総補正開度Ｄｅ）はＥＧＲバルブ１３に与えられてＥＧＲバルブ１３は閉止され、且つ、最終ＶＧＴＶ開度（総補正開度Ｄｔ）は容量可変手段１０へ与えられて可変容量ターボ１の容量可変手段１０が調整され、タービン１ｂの静翼が絞られる。 Further, in the corrected opening degree calculation unit 23, for example, when it is determined that sudden acceleration is based on the temporal change rate ΔQ of the fuel injection amount Q, the calculation is performed according to the flow of FIGS. The EGR V opening (total correction opening De) is given to the EGR valve 13, the EGR valve 13 is closed, and the final VGT V opening (total correction opening Dt) is given to the variable capacity means 10 and is variable. The capacity variable means 10 of the capacity turbo 1 is adjusted, and the stationary blades of the turbine 1b are throttled.

補正噴射圧決定部２４では、エンジン回転数Ｎ及び総補正開度Ｄｅを基に、図１１に示すマップから補正噴射圧Ｐ１が求められ、求められた補正噴射圧Ｐ１は、指示噴射圧算出部２５へ与えられる。   In the corrected injection pressure determining unit 24, the corrected injection pressure P1 is obtained from the map shown in FIG. 11 on the basis of the engine speed N and the total corrected opening De, and the obtained corrected injection pressure P1 is calculated as the commanded injection pressure calculating unit. 25.

指示噴射圧算出部２５では、エンジン回転数Ｎ及び燃料噴射量Ｑを基に、図１２に示すマップにより目標噴射圧Ｐｏが求められ、目標噴射圧Ｐｏと補正噴射圧Ｐ１が加算されて指示噴射圧Ｐが求められ（Ｐ＝Ｐｏ＋Ｐ１）、求められた指示噴射圧Ｐは燃料噴射ポンプ１５の圧力制御弁に与えられる。このため、燃料噴射ノズルから吐出される燃料は所定の圧力に制御された状態でピストン燃焼室へ噴射される。   The command injection pressure calculation unit 25 obtains the target injection pressure Po from the map shown in FIG. 12 based on the engine speed N and the fuel injection amount Q, and adds the target injection pressure Po and the corrected injection pressure P1 to indicate the command injection. The pressure P is obtained (P = Po + P1), and the obtained command injection pressure P is given to the pressure control valve of the fuel injection pump 15. For this reason, the fuel discharged from the fuel injection nozzle is injected into the piston combustion chamber while being controlled to a predetermined pressure.

上記制御においては、例えば加速時には上記したようにＥＧＲバルブ１３を略全閉にするが、ＥＧＲバルブ１３を閉め過ぎた場合には、排ガスが減少して実吸気量Ｆが多くなるため、燃料の指示噴射圧Ｐは減少するよう制御が行われる。又、このロジックは減速時においても働き、実吸気量Ｆが多くなると指示噴射圧Ｐは減少するよう制御が行われる。一方、実吸気量Ｆが少ない場合には、指示噴射圧Ｐは増加するよう制御が行われる。更に、同時に、ＥＧＲバルブ１３は開度が多くなって、実吸気量Ｆが減少するよう制御が行われる。従って、補正噴射圧Ｐ１は＋の場合も−の場合もある。   In the above control, for example, during acceleration, the EGR valve 13 is substantially fully closed as described above. However, if the EGR valve 13 is closed too much, the exhaust gas is reduced and the actual intake air amount F is increased. Control is performed so that the command injection pressure P decreases. This logic also works during deceleration, and control is performed so that the commanded injection pressure P decreases as the actual intake air amount F increases. On the other hand, when the actual intake air amount F is small, the command injection pressure P is controlled to increase. At the same time, the EGR valve 13 is controlled so that the opening degree increases and the actual intake air amount F decreases. Therefore, the corrected injection pressure P1 may be + or-.

図１３には、アイドル運転状態を基点として、エンジンの加速時に、燃料の噴射圧制御を行った場合と行わなかった場合の黒煙とＮＯｘとの関係が図示されている。この図から、噴射圧制御が行われなかった場合には、黒煙は若干減少するが、ＮＯｘが著しく増加するのに対し、噴射圧制御を行った場合には、黒煙は噴射圧制御を行わなかった場合に比較して、若干増加するが、ＮＯｘは著しく減少することが明らかである。従って、燃料の噴射圧制御を行うことにより、過渡時のＮＯｘの増大を抑制することができ、エンジン２の過渡運転時における排ガス性能を向上させることができる。なお、加速時にはアクスル開度Ａｃを大きくしてエンジン回転数Ｎと燃料噴射量Ｑとを増加させることになる。   FIG. 13 shows the relationship between black smoke and NOx when the fuel injection pressure control is performed and when the fuel injection pressure control is not performed during the acceleration of the engine with the idle operation state as a base point. From this figure, when the injection pressure control is not performed, the black smoke slightly decreases, but NOx increases remarkably, whereas when the injection pressure control is performed, the black smoke does not perform the injection pressure control. It is clear that NOx decreases significantly, although it increases slightly compared to the case where it is not performed. Therefore, by controlling the fuel injection pressure, it is possible to suppress an increase in NOx during the transition and to improve the exhaust gas performance during the transient operation of the engine 2. During acceleration, the axle opening degree Ac is increased to increase the engine speed N and the fuel injection amount Q.

図１４には、アイドル状態を基点として同じパターンで加速を行い、指示噴射圧Ｐをどの程度減少させれば排ガス性能が向上するかが図示されている。すなわち、基点における燃料の噴射圧に対し、指示噴射圧Ｐの減少幅を５ＭＰａ、１０ＭＰａ、２０ＭＰａと変化させた場合には、減少幅を大きくするに従い黒煙は若干増加するが、ＮＯｘは減少することが分かる。これを他の加速パターンについても行ってプロットすれば、加速時に指示噴射圧Ｐをどれ程減少させれば良いかのマップを作成することができる。   FIG. 14 shows how much the indicated injection pressure P is reduced by accelerating in the same pattern with the idle state as a base point to improve the exhaust gas performance. That is, when the decrease range of the command injection pressure P is changed to 5 MPa, 10 MPa, and 20 MPa with respect to the fuel injection pressure at the base point, the black smoke slightly increases but the NOx decreases as the decrease range is increased. I understand that. If this is performed for other acceleration patterns and plotted, a map of how much the command injection pressure P should be reduced during acceleration can be created.

図１５には、噴射圧制御を行わなかった場合と、噴射圧制御を行った場合のＮＯｘと黒煙の関係が図示されている。このグラフから、噴射圧制御を行うと、噴射圧制御を行わなかった場合と比較して、黒煙は若干増加するが、ＮＯｘは著しく減少することが分かる。   FIG. 15 shows the relationship between NOx and black smoke when the injection pressure control is not performed and when the injection pressure control is performed. From this graph, it can be seen that when the injection pressure control is performed, the black smoke slightly increases but the NOx significantly decreases as compared with the case where the injection pressure control is not performed.

図１６〜図１８には、［背景技術］で説明した従来技術のように燃料の噴射圧を制御しなかった場合と、本図示例のように燃料の噴射圧を制御した場合のＥＧＲバルブ開度の経時的変化の状態、可変容量ターボの開度の経時的変化の状態、新気吸入量の経時的変化の状態を図示している。図１６〜図１８中、実線は本図示例の場合を示し、点線は［背景技術］に示す従来の場合を示している。これらの図から、加速のような過渡時において、従来はＥＧＲバルブ開度がそれほど絞られないのに対し、本図示例では略全閉状態まで絞られ、又、可変容量ターボ開度も従来はそれほど絞られなかったのに対し、本図示例ではかなり絞られ、その結果、新気吸入量は従来よりも本図示例において多量となることが明らかである。これは、急加速時には還流する排ガスが減少することを意味している。しかし、燃料の噴射圧を減少させる制御を行うことにより、上述のように、ＮＯｘの増加を抑制することができ、排ガス性能を向上させることができる。   FIGS. 16 to 18 show the EGR valve opening when the fuel injection pressure is not controlled as in the prior art described in [Background Art] and when the fuel injection pressure is controlled as in this illustrated example. The state of the change over time of the degree, the state of change over time of the opening of the variable capacity turbo, and the state of change over time of the fresh air intake amount are illustrated. 16 to 18, the solid line indicates the case of this illustrated example, and the dotted line indicates the conventional case shown in [Background Art]. From these figures, during a transition such as acceleration, the EGR valve opening is not throttled so much in the past, but in the illustrated example, it is throttled to a substantially fully closed state. Although it was not squeezed so much, it is clearly squeezed in the illustrated example, and as a result, it is clear that the fresh air intake amount is larger in the illustrated example than in the past. This means that the exhaust gas that recirculates during rapid acceleration decreases. However, by controlling the fuel injection pressure to decrease, as described above, it is possible to suppress an increase in NOx and improve exhaust gas performance.

なお、本発明は、上述の図示例にのみ限定されるものではなく、本発明の要旨を逸脱しない範囲内において種々変更を加えることができる。すなわち、燃料の指示噴射圧ＰはＥＧＲバルブ１３の開度（変化量）を基に制御する場合について説明したが、ＥＧＲバルブ開度を実吸気量によりフィードバック制御する場合には、当該ＥＧＲバルブ開度は不足する吸気量により決まるため、不足吸気量で噴射圧を制御するようにしても、本図示例と同様の作用効果を奏することができる。   The present invention is not limited to the illustrated examples described above, and various modifications can be made without departing from the scope of the present invention. That is, the case where the command injection pressure P of the fuel is controlled based on the opening degree (change amount) of the EGR valve 13 has been described. However, when the EGR valve opening degree is feedback-controlled by the actual intake air amount, the EGR valve opening is controlled. Since the degree is determined by the insufficient intake air amount, even if the injection pressure is controlled by the insufficient intake air amount, the same effect as in the illustrated example can be obtained.

本発明のエンジンシステムの構成図の一例である。It is an example of the block diagram of the engine system of this invention. 図１に示す演算制御装置のブロック図の一例である。It is an example of the block diagram of the arithmetic and control unit shown in FIG. 本発明のエンジンシステムにおいて急加速の際に適用するブロック図である。It is a block diagram applied in the case of rapid acceleration in the engine system of this invention. 図３に示すブロック図の急加速制御の部分の詳細ブロック図である。FIG. 4 is a detailed block diagram of a portion of rapid acceleration control in the block diagram shown in FIG. 3. 図３に示す急加速制御割合算出の部分の詳細ブロック図である。FIG. 4 is a detailed block diagram of a portion for calculating a sudden acceleration control ratio shown in FIG. 3. 本発明のエンジンシステムにおいて、エンジン回転数とアクセル開度から燃料噴射量を求めるためのマップの一例である。In the engine system of this invention, it is an example of the map for calculating | requiring a fuel injection quantity from an engine speed and an accelerator opening. 本発明のエンジンシステムにおいて、エンジン回転数と燃料噴射量から目標吸気量を求めるためのマップの一例である。In the engine system of this invention, it is an example of the map for calculating | requiring the target intake air quantity from an engine speed and fuel injection quantity. 本発明のエンジンシステムにおいて、エンジン回転数と燃料噴射量からＥＧＲバルブの基本開度を求めるためのマップの一例である。In the engine system of this invention, it is an example of the map for calculating | requiring the basic opening degree of an EGR valve from an engine speed and fuel injection quantity. 本発明のエンジンシステムにおいて、吸気量偏差からＥＧＲバルブの補正開度を求めるためのマップの一例である。In the engine system of this invention, it is an example of the map for calculating | requiring the correction opening degree of an EGR valve from intake amount deviation. 本発明のエンジンシステムにおいて、エンジン回転数と燃料噴射量の時間的変化量からＥＧＲバルブの補正開度を求めるためのマップの一例である。In the engine system of this invention, it is an example of the map for calculating | requiring the correction | amendment opening degree of an EGR valve from the amount of time change of an engine speed and a fuel injection amount. 本発明のエンジンシステムにおいて、エンジン回転数とＥＧＲバルブの補正開度から燃料の補正噴射圧を求めるためのマップの一例である。In the engine system of this invention, it is an example of the map for calculating | requiring the correction injection pressure of a fuel from an engine speed and the correction opening degree of an EGR valve. 本発明のエンジンシステムにおいて、エンジン回転数と燃料噴射量から燃料の目標噴射圧を求めるためのマップの一例である。In the engine system of this invention, it is an example of the map for calculating | requiring the target injection pressure of fuel from an engine speed and fuel injection quantity. 本発明のエンジンシステムにおいて、噴射圧制御なしと噴射圧制御ありの場合の黒煙とＮＯｘとの関係を示すグラフである。In the engine system of the present invention, it is a graph showing the relationship between black smoke and NOx when there is no injection pressure control and there is injection pressure control. 本発明のエンジンシステムにおいて、噴射圧を段階的に変化させた場合の黒煙とＮＯｘとの関係を示すグラフである。In the engine system of this invention, it is a graph which shows the relationship between black smoke and NOx at the time of changing injection pressure in steps. 本発明のエンジンシステムにおいて、噴射圧制御なしと噴射圧制御ありの場合のＮＯｘと黒煙との関係を示すグラフである。In the engine system of the present invention, it is a graph showing the relationship between NOx and black smoke when there is no injection pressure control and there is injection pressure control. 従来と本図示例における過渡時のＥＧＲバルブ開度の経時的変化の状態を示すグラフである。It is a graph which shows the state of a time-dependent change of the EGR valve opening degree at the time of the transition in the past and this example of illustration. 従来と本図示例における過渡時の可変容量ターボ開度の経時的変化の状態を示すグラフである。It is a graph which shows the state of a time-dependent change of the variable capacity | capacitance turbo opening degree at the time of the transition in the past and this example of illustration. 従来と本図示例における過渡時の新気吸入量の経時的変化の状態を示すグラフである。It is a graph which shows the state of a time-dependent change of the fresh air inhalation amount at the time of the transition in the past and this example of illustration.

符号の説明Explanation of symbols

１ 可変容量ターボ
２ ディーゼルエンジン（エンジン）
１２ ＥＧＲ装置
１３ ＥＧＲバルブ
２１ 演算制御装置（手段）
２３ 補正開度算出部（手段）
２４ 補正噴射圧決定部（手段）
２５ 指示噴射圧算出部（手段）
Ｄ１ 補正開度（開度の変化量）
Ｄ２ 補正開度（開度の変化量）
Ｐ 指示噴射圧（噴射圧） 1 Variable capacity turbo 2 Diesel engine (engine)
12 EGR device 13 EGR valve 21 Arithmetic control device (means)
23 Correction Opening Calculation Unit (Means)
24 Correction Injection Pressure Determination Unit (Means)
25 Instructed injection pressure calculation unit (means)
D1 Corrected opening (change in opening)
D2 Corrected opening (change in opening)
P Instructed injection pressure (injection pressure)

Claims (2)

吸気を過給してエンジンの燃焼室に送給するための可変容量ターボと、前記エンジンからの排ガスの一部を吸気側に還流するＥＧＲ装置を備えたエンジンシステムにおいて、前記ＥＧＲ装置におけるＥＧＲバルブの開度の変化量、若しくは吸気側の不足吸気量を基に、前記エンジンの燃焼室に噴射される燃料の噴射圧を制御するようにした手段を設けたことを特徴とするエンジンシステム。   An engine system comprising a variable capacity turbocharger for supercharging intake air and supplying it to a combustion chamber of the engine, and an EGR device for returning a part of exhaust gas from the engine to the intake side, and an EGR valve in the EGR device An engine system comprising means for controlling an injection pressure of fuel injected into a combustion chamber of the engine based on a change amount of the opening of the engine or a short intake amount on the intake side. 吸気を過給してエンジンの燃焼室に送給するための可変容量ターボと、前記エンジンからの排ガスの一部を吸気側に還流するＥＧＲ装置を備えたエンジンシステムにおいて、加速時には、前記ＥＧＲ装置におけるＥＧＲバルブの開度の変化量、若しくは吸気側の不足吸気量を基に、前記エンジンの燃焼室に噴射される燃料の噴射圧を減少させるように制御する手段を設けたことを特徴とするエンジンシステム。   In an engine system comprising a variable capacity turbocharger for supercharging intake air and supplying it to a combustion chamber of the engine, and an EGR device for recirculating a part of exhaust gas from the engine to the intake side, the EGR device And a means for controlling to reduce the injection pressure of the fuel injected into the combustion chamber of the engine on the basis of the amount of change in the opening of the EGR valve or the insufficient intake amount on the intake side. Engine system.
JP2003419247A 2003-12-17 2003-12-17 Engine system Pending JP2005180234A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012163107A (en) * 2012-04-16 2012-08-30 Yanmar Co Ltd Electronic control system engine
JP2014080980A (en) * 2013-12-18 2014-05-08 Yanmar Co Ltd Electronic control type engine

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012163107A (en) * 2012-04-16 2012-08-30 Yanmar Co Ltd Electronic control system engine
JP2014080980A (en) * 2013-12-18 2014-05-08 Yanmar Co Ltd Electronic control type engine

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