JP2002188522A - Egr control device for engine with turbocharger - Google Patents
Egr control device for engine with turbochargerInfo
- Publication number
- JP2002188522A JP2002188522A JP2000382115A JP2000382115A JP2002188522A JP 2002188522 A JP2002188522 A JP 2002188522A JP 2000382115 A JP2000382115 A JP 2000382115A JP 2000382115 A JP2000382115 A JP 2000382115A JP 2002188522 A JP2002188522 A JP 2002188522A
- Authority
- JP
- Japan
- Prior art keywords
- egr
- mode
- passage
- intake
- engine
- 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.)
- Withdrawn
Links
Classifications
-
- 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
- F02M26/07—Mixed pressure loops, i.e. wherein recirculated exhaust gas is either taken out upstream of the turbine and reintroduced upstream of the compressor, or is taken out downstream of the turbine and reintroduced downstream of the compressor
-
- 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
- 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
- F02M26/14—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the exhaust system
- F02M26/15—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the exhaust system in relation to engine exhaust purifying apparatus
-
- 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
- F02M26/42—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories having two or more EGR passages; EGR systems specially adapted for engines having two or more cylinders
- F02M26/44—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories having two or more EGR passages; EGR systems specially adapted for engines having two or more cylinders in which a main EGR passage is branched into multiple passages
-
- 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
- F02M26/65—Constructional details of EGR valves
- F02M26/71—Multi-way valves
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)
- Combined Controls Of Internal Combustion Engines (AREA)
- Supercharger (AREA)
- Exhaust-Gas Circulating Devices (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、ターボチャージャ
付きエンジンに適用されるＥＧＲ制御装置に関するもの
である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EGR control device applied to a turbocharged engine.
【０００２】[0002]
【関連する背景技術】周知のようにエミッション対策の
一つとして、エンジンから排出された排ガスを吸気通路
に還流させて燃焼温度の低下によりＮＯｘの排出量を低
減するＥＧＲ制御装置が実施されている。この種のＥＧ
Ｒ制御装置はターボチャージャを備えたエンジンに適用
される場合があり、例えば特開平８−２４６９６３号公
報に記載のものを挙げることができる。このＥＧＲ制御
装置では、排気通路のタービン上流側と吸気通路のコン
プレッサ下流側とを第１還流通路により接続すると共
に、排気通路のタービン下流側と吸気通路のコンプレッ
サ下流側とを第２還流通路により接続し、エンジン負荷
に応じて切換弁により両還流通路を選択的に開放するよ
うに構成されている。2. Description of the Related Art As one well-known emission measure, an EGR control device that recirculates exhaust gas discharged from an engine to an intake passage to reduce NOx emission by lowering combustion temperature has been implemented. . This kind of EG
The R control device may be applied to an engine equipped with a turbocharger, for example, the one described in Japanese Patent Application Laid-Open No. H8-246963. In this EGR control device, the upstream of the turbine in the exhaust passage and the downstream of the compressor in the intake passage are connected by a first return passage, and the downstream of the turbine in the exhaust passage and the downstream of the compressor in the intake passage are connected by a second return passage. The two return passages are selectively opened by a switching valve according to the engine load.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、上記し
た公報に記載のＥＧＲ制御装置を、例えば筒内噴射型エ
ンジンのように、運転状態に応じて燃焼モードを切換え
るエンジンに適用した場合には、以下に述べる不具合が
生じる。即ち、空燃比を理論空燃比付近に制御する通常
のエンジンでは、エンジン負荷や回転速度の増加により
ターボチャージャの過給効果が得られる領域では、吸気
通路が正圧に上昇して排気通路側からのＥＧＲを還流し
難くなるものの、それ以下の領域ではＥＧＲの還流に支
障は生じない。これに対して筒内噴射型エンジンでは、
図２のマップに示すように、理論空燃比のストイキモー
ドより目標平均有効圧Ｐe（エンジン負荷を表す）及び
エンジン回転速度Ｎeが低い領域において、空燃比をリ
ーン側に制御する圧縮リーンモードを実行しており、こ
の圧縮リーンモードでは、希薄燃焼のために多量の吸入
空気を導入することから、ストイキモードに比較してタ
ーボチャージャの過給効果が増加する。その結果、圧縮
リーンモード内にも、吸気通路内が正圧となる領域が存
在することになる。However, when the EGR control device described in the above-mentioned publication is applied to an engine that switches the combustion mode according to the operating state, such as a direct injection engine, The following problems occur. That is, in a normal engine in which the air-fuel ratio is controlled near the stoichiometric air-fuel ratio, in a region where a turbocharger effect is obtained due to an increase in the engine load or the rotational speed, the intake passage rises to a positive pressure, and the intake passage increases from the exhaust passage side Although it is difficult to recirculate the EGR, there is no problem in recirculating the EGR in a region below the EGR. On the other hand, in a direct injection engine,
As shown in the map of FIG. 2, in a region where the target average effective pressure Pe (representing the engine load) and the engine speed Ne are lower than the stoichiometric mode of the stoichiometric air-fuel ratio, the compression lean mode for controlling the air-fuel ratio to the lean side is executed. In this compression lean mode, a large amount of intake air is introduced for lean combustion, so that the supercharging effect of the turbocharger is increased as compared with the stoichiometric mode. As a result, even in the compression lean mode, there is a region where the inside of the intake passage has a positive pressure.
【０００４】つまり、筒内噴射型エンジンでは、ストイ
キモードと圧縮リーンモードとの境界で吸気通路の圧力
が急変することから、それに応じてＥＧＲの還流状態を
制御して、何れのモード領域でも確実にＥＧＲを還流さ
せる対策が必要となる。しかしながら、上記した公報に
記載のＥＧＲ制御装置では、このようなモード切換の影
響については何ら想定しておらず、単にエンジン負荷に
応じて還流通路を切換えるだけのため、特にストイキモ
ードと圧縮リーンモードとの境界付近の領域で必要量の
ＥＧＲを還流させることができず、一時的にＮＯｘ排出
量を増大させてしまうという問題がある。That is, in the direct injection type engine, since the pressure in the intake passage changes suddenly at the boundary between the stoichiometric mode and the compression lean mode, the recirculation state of the EGR is controlled in accordance with the sudden change, so that the engine is reliably operated in any mode region. Therefore, it is necessary to take measures to recirculate EGR. However, in the EGR control device described in the above-mentioned publication, the influence of such mode switching is not assumed at all, and since the recirculation passage is simply switched according to the engine load, the stoichiometric mode and the compression lean mode are particularly used. There is a problem that the required amount of EGR cannot be recirculated in the region near the boundary with the above, and the NOx emission amount is temporarily increased.
【０００５】本発明の目的は、燃焼モードの切換に伴っ
て吸気通路の圧力が急変しても必要量のＥＧＲを還流で
き、もって、常に確実にＮＯｘ低減を達成することがで
きるターボチャージャ付きエンジンのＥＧＲ制御装置を
提供することにある。An object of the present invention is to provide an engine with a turbocharger which can recirculate a required amount of EGR even if the pressure in the intake passage changes suddenly in accordance with the switching of the combustion mode, and thus can always reliably reduce NOx. To provide an EGR control device.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するた
め、本発明では、排気タービンと吸気コンプレッサとを
同軸上に連結したターボチャージャを備えると共に、理
論空燃比より希薄側に空燃比を制御する第１燃焼モード
と、第１燃焼モードより濃化側に空燃比を制御する第２
燃焼モードとを運転状態に応じて切換可能なエンジンに
おいて、排気タービンの下流側の排気通路に設けられた
排ガス浄化触媒と、吸気コンプレッサの下流側の吸気通
路に設けられたスロットルバルブと、排ガス浄化触媒の
下流側の排気通路とスロットルバルブの下流側の吸気通
路とを連通する第１ＥＧＲ通路と、排気タービンの上流
側の排気通路とスロットルバルブの下流側の吸気通路と
を連通する第２ＥＧＲ通路と、第１ＥＧＲ通路と第２Ｅ
ＧＲ通路とを選択的に開放する通路切換手段と、少なく
とも第１燃焼モードと第２燃焼モードとの境界付近にお
いて、第１燃焼モードの運転領域では通路切換手段によ
り第２ＥＧＲ通路を開放し、第２燃焼モードの運転領域
では通路切換手段により第１ＥＧＲ通路を開放する制御
手段とを備えた。In order to achieve the above object, according to the present invention, there is provided a turbocharger in which an exhaust turbine and an intake compressor are coaxially connected, and the air-fuel ratio is controlled to be leaner than the stoichiometric air-fuel ratio. A first combustion mode and a second combustion mode for controlling the air-fuel ratio to a more enriched side than the first combustion mode.
An exhaust gas purifying catalyst provided in an exhaust passage downstream of an exhaust turbine, a throttle valve provided in an intake passage downstream of an intake compressor, and an exhaust gas purifying device. A first EGR passage communicating the exhaust passage downstream of the catalyst with an intake passage downstream of the throttle valve; a second EGR passage communicating the exhaust passage upstream of the exhaust turbine with the intake passage downstream of the throttle valve; , The first EGR passage and the second E
A passage switching means for selectively opening the GR passage, and at least near a boundary between the first combustion mode and the second combustion mode, the second EGR passage is opened by the passage switching means in an operation region of the first combustion mode; Control means for opening the first EGR passage by the passage switching means in the operation region of the two-combustion mode.
【０００７】空燃比が希薄側に制御される第１燃焼モー
ドでは、希薄燃焼のために多量の吸入空気を導入するこ
とから、濃化側の第２燃焼モードに比較してターボチャ
ージャの過給効果が増加する。よって、第２燃焼モード
に対して第１燃焼モードでは吸気通路の圧力が高くな
り、両燃焼モード間の切換時には、その境界で吸気通路
の圧力が急変することになる。In the first combustion mode in which the air-fuel ratio is controlled to the lean side, a large amount of intake air is introduced for lean combustion. The effect increases. Therefore, the pressure in the intake passage becomes higher in the first combustion mode than in the second combustion mode, and when switching between the two combustion modes, the pressure in the intake passage suddenly changes at the boundary.
【０００８】上記のように第２燃焼モードの運転領域で
は、第１ＥＧＲ通路が開放される。第１ＥＧＲ通路が接
続された排ガス浄化触媒の下流側は圧力が低いものの、
第２燃焼モードではターボチャージャの過給効果も低い
ことから、吸気通路側の圧力は更に低くなっており、Ｅ
ＧＲ還流のための吸排気間の差圧が確保されて、排ガス
が吸気通路側に還流される。As described above, in the operation region of the second combustion mode, the first EGR passage is opened. Although the pressure on the downstream side of the exhaust gas purification catalyst to which the first EGR passage is connected is low,
In the second combustion mode, since the turbocharging effect of the turbocharger is low, the pressure on the intake passage side is further reduced.
A differential pressure between intake and exhaust for GR recirculation is ensured, and exhaust gas is recirculated to the intake passage side.
【０００９】又、第１燃焼モードでは、第２ＥＧＲ通路
が開放される。この第１燃焼モードではターボチャージ
ャの過給効果により吸気通路側の圧力が高められている
ものの、排気タービンの上流側はそれ以上の圧力を有す
ることからＥＧＲ還流のための差圧が確保され、排ガス
が吸気通路側に還流される。そして、以上のように燃焼
モードに応じてＥＧＲ通路を切換えることから、モード
切換に伴ってターボチャージャの過給効果が増減して吸
気通路の圧力が急変しても、常に必要量のＥＧＲを確実
に還流可能となる。In the first combustion mode, the second EGR passage is opened. In this first combustion mode, although the pressure on the intake passage side is increased by the supercharging effect of the turbocharger, the differential pressure for EGR recirculation is ensured because the upstream side of the exhaust turbine has a higher pressure. The exhaust gas is returned to the intake passage side. Since the EGR passage is switched in accordance with the combustion mode as described above, the required amount of EGR is always ensured even if the turbocharger effect increases or decreases due to the mode switching and the pressure in the intake passage changes suddenly. It is possible to reflux.
【００１０】しかも、吸気通路の圧力が比較的低くてＥ
ＧＲを還流し易い第２燃焼モード時には、排ガス浄化触
媒の下流側の排ガス、つまり、排ガス浄化触媒により煤
をトラップされた煤含有量の低い排ガスを還流させるこ
とから、吸気系へのカーボンの堆積を抑制可能となる。In addition, since the pressure in the intake passage is relatively low, E
In the second combustion mode in which the GR is easily circulated, the exhaust gas downstream of the exhaust gas purification catalyst, that is, the exhaust gas having a low soot content in which the soot is trapped by the exhaust gas purification catalyst is circulated, so that carbon is deposited on the intake system. Can be suppressed.
【００１１】[0011]
【発明の実施の形態】以下、本発明を具体化したターボ
チャージャ付きエンジンのＥＧＲ制御装置の一実施形態
を説明する。本実施形態のエンジンは燃焼室内に直接燃
料を噴射する筒内噴射型ガソリンエンジンとして構成さ
れており、図１の全体構成図に示すように、エンジン１
のシリンダヘッド２にはインテークマニホールド３及び
サージタンク４を介して吸気管５が接続されている。吸
気管５のサージタンク４入口付近にはスロットルバルブ
６が設けられると共に、その上流側にターボチャージャ
７の吸気コンプレッサ７ａが設けられている。本実施形
態では、これらのインテークマニホールド３、サージタ
ンク４及び吸気管５により吸気通路が構成されている。
そして、エアクリーナ８を介して吸気管５内に導入され
た吸入空気は吸気コンプレッサ７ａにより圧縮された
後、スロットルバルブ６により流量調整されて燃焼室内
に供給される。尚、吸気コンプレッサ７ａによる過給圧
は、周知のウエストゲートバルブ９により調整される。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an EGR control device for a turbocharged engine embodying the present invention will be described below. The engine of this embodiment is configured as a direct injection gasoline engine that injects fuel directly into a combustion chamber. As shown in the overall configuration diagram of FIG.
An intake pipe 5 is connected to the cylinder head 2 via an intake manifold 3 and a surge tank 4. A throttle valve 6 is provided near the inlet of the surge tank 4 of the intake pipe 5, and an intake compressor 7a of a turbocharger 7 is provided upstream thereof. In the present embodiment, the intake manifold 3, the surge tank 4, and the intake pipe 5 constitute an intake passage.
Then, the intake air introduced into the intake pipe 5 through the air cleaner 8 is compressed by the intake compressor 7a, adjusted in flow rate by the throttle valve 6, and supplied to the combustion chamber. The supercharging pressure by the intake compressor 7a is adjusted by a well-known wastegate valve 9.
【００１２】又、エンジン１のシリンダヘッド２にはエ
キゾーストマニホールド１０及び排ガス浄化触媒として
の近接触媒１１を介して排気管１２が接続され、エキゾ
ーストマニホールド１０には、前記吸気コンプレッサ７
ａと同軸上に連結された排気タービン７ｂが設けられて
いる。本実施形態では、これらのエキゾーストマニホー
ルド１０及び排気管１２により排気通路が構成されてい
る。そして、エンジン１の燃焼室で燃焼後の排ガスは排
気タービン７ｂを回転駆動した後に近接触媒１１内を通
過し、その後に排気管１２に案内されて図示しない排ガ
ス浄化用の床下触媒及び消音器を経て外部に排出され
る。An exhaust pipe 12 is connected to the cylinder head 2 of the engine 1 through an exhaust manifold 10 and a proximity catalyst 11 serving as an exhaust gas purifying catalyst. The exhaust manifold 10 is connected to the intake compressor 7.
An exhaust turbine 7b is provided coaxially with a. In the present embodiment, an exhaust passage is constituted by the exhaust manifold 10 and the exhaust pipe 12. Then, the exhaust gas after combustion in the combustion chamber of the engine 1 passes through the proximity catalyst 11 after rotating and driving the exhaust turbine 7b, and thereafter is guided to the exhaust pipe 12 to remove the underfloor catalyst for exhaust gas purification and the muffler (not shown). Is discharged to the outside.
【００１３】前記近接触媒１１の下流側には第１ＥＧＲ
通路１３の一端が接続され、又、前記排気タービン７ｂ
の上流側には第２ＥＧＲ通路１４の一端が接続されてい
る。これらの第１及び第２ＥＧＲ通路１３，１４の他端
は、共に通路切換手段としてのＥＧＲ切換バルブ１５及
び共用ＥＧＲ通路１６を介して前記サージタンク４に接
続され、ＥＧＲ切換バルブ１５は、第１ＥＧＲ通路１３
と第２ＥＧＲ通路１４とを選択的に開放して共用ＥＧＲ
通路１６に連通させる。又、共用ＥＧＲ通路１６にはＥ
ＧＲ調整バルブ１７が設けられ、このＥＧＲ調整バルブ
１７の開度に応じて、共用ＥＧＲ通路１６を流通する排
ガスの流量が調整される。A first EGR is provided downstream of the proximity catalyst 11.
One end of the passage 13 is connected, and the exhaust turbine 7b
One end of the second EGR passage 14 is connected to an upstream side of the second EGR passage 14. The other ends of the first and second EGR passages 13 and 14 are both connected to the surge tank 4 via an EGR switching valve 15 as a passage switching means and a shared EGR passage 16, and the EGR switching valve 15 is connected to the first EGR passage. Passage 13
And the second EGR passage 14 is selectively opened to share EGR.
It communicates with the passage 16. The shared EGR passage 16 has E
A GR adjustment valve 17 is provided, and the flow rate of exhaust gas flowing through the common EGR passage 16 is adjusted according to the opening of the EGR adjustment valve 17.
【００１４】一方、車室内には入出力装置、記憶装置
（ＲＯＭ、ＲＡＭ等）、中央処理装置（ＣＰＵ）、タイ
マカウンタ等を備えたＥＣＵ（電子コントロールユニッ
ト）２１が設置されている。ＥＣＵ２１の入力側には、
吸気管５内に導入される吸入空気量Ｑを検出するカルマ
ン渦式のエアフローセンサ２２、エンジン１の回転速度
Ｎeを検出する回転速度センサ２３等が接続されてお
り、これらセンサ類からの検出情報が入力される。ＥＣ
Ｕ２１の出力側には、前記ＥＧＲ切換バルブ１５、ＥＧ
Ｒ調整バルブ１７、ウエストゲートバルブ９が接続され
ると共に、エンジン１の図示しない点火プラグや燃料噴
射弁等が接続されている。本実施形態では、このＥＣＵ
２１が制御手段として機能する。On the other hand, an ECU (electronic control unit) 21 having an input / output device, a storage device (ROM, RAM, etc.), a central processing unit (CPU), a timer counter and the like is installed in the vehicle interior. On the input side of the ECU 21,
A Karman vortex airflow sensor 22 for detecting the amount of intake air Q introduced into the intake pipe 5, a rotational speed sensor 23 for detecting the rotational speed Ne of the engine 1, and the like are connected, and detection information from these sensors is provided. Is entered. EC
On the output side of U21, the EGR switching valve 15, EG
The R adjustment valve 17 and the wastegate valve 9 are connected, and an unillustrated ignition plug, a fuel injection valve, and the like of the engine 1 are connected. In the present embodiment, this ECU
21 functions as control means.
【００１５】そして、ＥＣＵ２１はエンジン１の運転状
態に基づいて点火時期、燃料噴射量、目標過給圧等を算
出し、点火プラグ、燃料噴射弁、ウエストゲートバルブ
９を駆動制御して、エンジン１を運転させる。ここで、
筒内噴射型エンジン１では、吸気行程のみならず圧縮行
程でも燃料噴射可能なため、エンジン１の運転状態に応
じて燃料噴射モード（燃焼モード）を切換えている。即
ち、ＥＣＵ２１は図２のマップに基づき、エンジン負荷
を表す目標平均有効圧Ｐe及びエンジン回転速度Ｎeの増
加に応じて、燃料噴射モードを圧縮リーンモード、スト
イキモード、Ｏ／Ｌモードの順に切換え、その燃料噴射
モードに対応する行程で燃料噴射を実行する。The ECU 21 calculates an ignition timing, a fuel injection amount, a target supercharging pressure, and the like based on the operation state of the engine 1 and controls the driving of the ignition plug, the fuel injection valve, and the wastegate valve 9 to control the engine 1 Drive. here,
In the in-cylinder injection engine 1, fuel can be injected not only in the intake stroke but also in the compression stroke. Therefore, the fuel injection mode (combustion mode) is switched according to the operating state of the engine 1. That is, the ECU 21 switches the fuel injection mode to the compression lean mode, the stoichiometric mode, and the O / L mode in accordance with the target average effective pressure Pe representing the engine load and the increase of the engine speed Ne based on the map of FIG. The fuel injection is executed in a stroke corresponding to the fuel injection mode.
【００１６】Ｏ／Ｌモードとストイキモードは共に吸気
行程で燃料噴射するモードであり、目標空燃比がストイ
キ（理論空燃比）よりもリッチ側（濃化側）の空燃比に
設定される。Ｏ／Ｌモードではオープンループにより空
燃比をリッチ側に制御し、ストイキモードでは図示しな
いＯ2センサの検出に基づいて空燃比をストイキに制御
する。又、圧縮リーンモードは圧縮行程で燃料噴射する
モードであり、点火プラグの周囲にストイキ付近の点火
可能な混合気を集中させながら、その周囲にリーンな空
燃比の混合気を存在させることで、超リーンな全体空燃
比に制御する。Both the O / L mode and the stoichiometric mode are modes in which fuel is injected during the intake stroke, and the target air-fuel ratio is set to an air-fuel ratio that is richer (richer) than stoichiometric (the stoichiometric air-fuel ratio). The O / L mode to control the air-fuel ratio to the rich side by the open-loop control the air-fuel ratio to the stoichiometric based on the detection of the O 2 sensor (not shown) in the stoichiometric mode. The compression lean mode is a mode in which fuel is injected in the compression stroke.By concentrating the ignitable air-fuel mixture near the stoichiometric gas around the ignition plug, the air-fuel mixture having a lean air-fuel ratio exists around the ignition plug. Control the air-fuel ratio to be super lean.
【００１７】一方、ＥＣＵ２１はエンジン１の運転状態
に基づきＥＧＲ調整バルブ１７の開度を制御して、排気
側から吸気側に還流されるＥＧＲ量を調整すると共に、
このときのＥＧＲ還流に利用されるＥＧＲ通路１３，１
４を、エンジン１の運転状態に基づいてＥＧＲ切換バル
ブ１５により切換える。そこで、このＥＣＵ２１によっ
て行われるＥＧＲ制御を以下に詳述する。On the other hand, the ECU 21 controls the opening of the EGR control valve 17 based on the operating state of the engine 1 to adjust the amount of EGR recirculated from the exhaust side to the intake side,
EGR passages 13, 1 used for EGR recirculation at this time
4 is switched by the EGR switching valve 15 based on the operating state of the engine 1. Therefore, the EGR control performed by the ECU 21 will be described in detail below.
【００１８】ＥＣＵ２１は図３及び図４に示すＥＧＲ制
御ルーチンを所定の制御インターバルで実行する。ま
ず、ＥＣＵ２１はステップＳ２で回転速度センサ２３か
らエンジン回転速度Ｎeを入力し、ステップＳ４でエア
フローセンサ２２から入力した吸入空気量Ｑに基づいて
エンジン１の体積効率Ｅvを算出し、又、図示しないス
ロットル開度又はアクセル操作量とエンジン回転速度Ｎ
eとに基づいて目標平均有効圧Ｐeを算出する。続くステ
ップＳ６では、現在の燃料噴射モードがＯ／Ｌモードで
あるか否かを判定し、ＹＥＳ（肯定）のときにはステッ
プＳ８に移行してＥＧＲ調整バルブ１７の開度を０（全
閉）とし、ステップＳ１０でＥＧＲ切換バルブ１５を第
２ＥＧＲ通路１４側に切換えた後、ルーチンを終了す
る。つまり、この場合にはＥＧＲ調整バルブ１７により
排ガスの流通が遮断されることから、第１及び第２ＥＧ
Ｒ通路１３，１４の切換状態に関係なく、吸気通路側へ
のＥＧＲ還流が中止される。The ECU 21 executes an EGR control routine shown in FIGS. 3 and 4 at a predetermined control interval. First, the ECU 21 inputs the engine rotation speed Ne from the rotation speed sensor 23 in step S2, calculates the volumetric efficiency Ev of the engine 1 based on the intake air amount Q input from the air flow sensor 22 in step S4, and does not illustrate. Throttle opening or accelerator operation amount and engine speed N
The target average effective pressure Pe is calculated based on e. In the following step S6, it is determined whether or not the current fuel injection mode is the O / L mode, and if YES (affirmative), the process proceeds to step S8 to set the opening of the EGR adjustment valve 17 to 0 (fully closed). After the EGR switching valve 15 is switched to the second EGR passage 14 in step S10, the routine ends. That is, in this case, since the flow of exhaust gas is shut off by the EGR adjustment valve 17, the first and second EGs are controlled.
Regardless of the switching state of the R passages 13 and 14, EGR recirculation to the intake passage side is stopped.
【００１９】このように第２ＥＧＲ通路１４に切換え、
更にＥＧＲ調整バルブ１７によってＥＧＲの流通を遮断
することにより、燃料噴射モードがストイキモードに切
換えられたときに、応答性を低減してＥＧＲを供給で
き、モード切換時のショックを低減できる。尚、ステッ
プＳ６での判定時に、エンジン回転速度Ｎeが所定値よ
り大きい場合には、ストイキモードに切り換わるとき
に、ストイキモードの低負荷高回転側に移動する可能性
が高いので、上記第２ＥＧＲ通路１４に代えて第１ＥＧ
Ｒ通路１３側に切換えて、ストイキモードへの切換に備
えてもよい。又、Ｏ／Ｌモード中でのエンジン回転速度
Ｎeに応じて第１ＥＧＲ通路１３と第２ＥＧＲ通路１４
とを切換えてもよい。この場合にはより一層ストイキモ
ードへの切換時のＥＧＲの応答遅れを低減しつつ、上述
した課題を効果的に解消できる。As described above, switching to the second EGR passage 14,
Further, by interrupting the flow of the EGR by the EGR adjustment valve 17, when the fuel injection mode is switched to the stoichiometric mode, the responsiveness can be reduced and the EGR can be supplied, and the shock at the time of the mode switching can be reduced. If the engine speed Ne is higher than the predetermined value at the time of the determination in step S6, there is a high possibility that the engine will move to the low-load high-speed side in the stoichiometric mode when switching to the stoichiometric mode. 1st EG instead of passage 14
The switching to the R passage 13 may be performed to prepare for switching to the stoichiometric mode. In addition, the first EGR passage 13 and the second EGR passage 14 are controlled according to the engine speed Ne in the O / L mode.
May be switched. In this case, the above-described problem can be effectively solved while further reducing the response delay of the EGR at the time of switching to the stoichiometric mode.
【００２０】又、前記ステップＳ６の判定がＮＯ（否
定）のときには、ステップＳ１２に移行して現在の燃料
噴射モードがストイキモードであるか否かを判定する。
判定がＹＥＳのときにはステップＳ１４に移行して、予
め設定されたストイキモード用のバルブ開度設定マップ
に基づき、体積効率Ｅv及びエンジン回転速度ＮeからＥ
ＧＲ調整バルブ１７の目標開度を求め、その目標開度を
達成すべくＥＧＲ調整バルブ１７を駆動制御する。If the determination in step S6 is NO (No), the process proceeds to step S12 to determine whether the current fuel injection mode is the stoichiometric mode.
When the determination is YES, the process proceeds to step S14, and based on the preset stoichiometric mode valve opening degree setting map, the volume efficiency Ev and the engine speed Ne are calculated based on the engine speed Ne.
The target opening of the GR adjustment valve 17 is obtained, and the drive of the EGR adjustment valve 17 is controlled to achieve the target opening.
【００２１】続くステップＳ１６では予め設定されたス
トイキモード用の判定値Ｅv0設定マップに基づき、エン
ジン回転速度Ｎeから判定値Ｅv0を求め、ステップＳ１
８で判定値Ｅv0に対して実際の体積効率Ｅvが大きいか
否か、換言すればエンジン１の負荷が大きいか否かを判
定する。ステップＳ１８の判定がＹＥＳのときには、ス
テップＳ２０でＥＧＲ切換バルブ１５を第２ＥＧＲ通路
１４側に切換え、又、判定がＮＯのときには、ステップ
Ｓ２２でＥＧＲ切換バルブ１５を第１ＥＧＲ通路１３側
に切換えた後、ルーチンを終了する。In the following step S16, a determination value Ev0 is obtained from the engine speed Ne based on a preset determination value Ev0 map for the stoichiometric mode.
In step 8, it is determined whether the actual volumetric efficiency Ev is greater than the determination value Ev0, in other words, whether the load on the engine 1 is greater. If the determination in step S18 is YES, the EGR switching valve 15 is switched to the second EGR passage 14 in step S20. If the determination is NO, the EGR switching valve 15 is switched to the first EGR passage 13 in step S22. Then, the routine ends.
【００２２】一方、前記ステップＳ１２の判定がＮＯの
ときには、現在の燃料噴射モードが圧縮リーンモードで
あると見なしてステップＳ２４に移行し、予め設定され
た圧縮リーンモード用のバルブ開度設定マップに基づ
き、目標平均有効圧Ｐe及びエンジン回転速度ＮeからＥ
ＧＲ調整バルブ１７の目標開度を求め、その目標開度を
達成すべくＥＧＲ調整バルブ１７を駆動制御する。On the other hand, if the determination in step S12 is NO, it is assumed that the current fuel injection mode is the compression lean mode, and the flow shifts to step S24, where a preset valve opening setting map for the compression lean mode is set. From the target average effective pressure Pe and the engine speed Ne to E
The target opening of the GR adjustment valve 17 is obtained, and the drive of the EGR adjustment valve 17 is controlled to achieve the target opening.
【００２３】尚、このようにストイキモードで用いた体
積効率Ｅvに代えて目標平均有効圧Ｐeを適用しているの
は、空燃比がリーン領域で変化する圧縮リーンモードで
は大量の吸入空気が導入されるため、吸入空気量Ｑの変
化が小さく、従って吸入空気量Ｑに基づいて算出される
体積効率Ｅvがエンジン負荷と相関しないことから、運
転者の意志が反映される目標平均有効圧Ｐｅで代用して
いるのである。これにより、それぞれのモードでエンジ
ン負荷に適切に対応したバルブ開度が設定される。The reason why the target average effective pressure Pe is applied in place of the volume efficiency Ev used in the stoichiometric mode is that a large amount of intake air is introduced in the compression lean mode in which the air-fuel ratio changes in a lean region. Therefore, since the change in the intake air amount Q is small and the volume efficiency Ev calculated based on the intake air amount Q does not correlate with the engine load, the target average effective pressure Pe reflecting the driver's intention is reflected. Instead. As a result, in each mode, the valve opening degree appropriately corresponding to the engine load is set.
【００２４】続くステップＳ２６では予め設定された圧
縮リーンモード用の判定値Ｐe0設定マップに基づき、エ
ンジン回転速度Ｎeから判定値Ｐe0を求め、ステップＳ
２８で判定値Ｅv0に対して実際の目標平均有効圧Ｐeが
大きいか否か、換言すればエンジン１の負荷が大きいか
否かを判定する。ステップＳ２８の判定がＹＥＳのとき
には、ステップＳ３０でＥＧＲ切換バルブ１５を第２Ｅ
ＧＲ通路１４側に切換え、又、判定がＮＯのときには、
ステップＳ３２でＥＧＲ切換バルブ１５を第１ＥＧＲ通
路１３側に切換えた後、ルーチンを終了する。In the following step S26, a determination value Pe0 is obtained from the engine rotation speed Ne based on a preset determination value Pe0 setting map for the compression lean mode.
At 28, it is determined whether the actual target average effective pressure Pe is greater than the determination value Ev0, in other words, whether the load on the engine 1 is greater. If the determination in step S28 is YES, in step S30 the EGR switching valve 15 is set to the second E position.
Switch to the GR passage 14 side, and when the determination is NO,
After the EGR switching valve 15 is switched to the first EGR passage 13 side in step S32, the routine ends.
【００２５】以上のＥＣＵ２１の制御により、ＥＧＲの
還流状況は以下のように切換えられる。まず、エンジン
１から排出される排ガスは、排気タービン７ｂ及び近接
触媒１１を通過する際に圧損を生じると共に、近接触媒
１１を通過する際に含有している煤の一部がトラップさ
れる。その結果、排気タービン７ｂの上流側において、
排ガスは比較的多くの煤を含有するものの、上記したス
トイキモード領域や圧縮リーンモード領域の正圧域のサ
ージタンク４内よりも高い圧力が確保され、一方、近接
触媒１１の下流側において、排ガスは上記正圧域のサー
ジタンク４内よりも圧力が低下するものの、煤含有量が
大幅に低減される傾向がある。Under the control of the ECU 21, the EGR recirculation state is switched as follows. First, the exhaust gas discharged from the engine 1 causes a pressure loss when passing through the exhaust turbine 7b and the proximity catalyst 11, and a part of soot contained when passing through the proximity catalyst 11 is trapped. As a result, on the upstream side of the exhaust turbine 7b,
Although the exhaust gas contains a relatively large amount of soot, a pressure higher than that in the surge tank 4 in the positive pressure region in the stoichiometric mode region or the compression lean mode region described above is secured. Although the pressure is lower than that in the surge tank 4 in the positive pressure range, the soot content tends to be significantly reduced.
【００２６】一方、前記判定値Ｅv0，Ｐe0は、図２中の
ストイキモード領域と圧縮リーンモード領域内におい
て、エンジン回転速度Ｎeに基づいて破線で示すライン
上に設定される。これらの判定値Ｅv0，Ｐe0は予めエン
ジン１の台上試験により設定されたものであり、ターボ
チャージャ７の過給効果により、エンジン回転速度Ｎe
及び目標平均有効圧Ｐeの増加と共にサージタンク４内
の圧力が負圧から正圧に転じる境界（つまり大気圧）に
設定されている。これによって、上述した問題が解決さ
れるのである。ここで、ストイキモード領域の負圧域よ
りエンジン回転速度Ｎe及び目標平均有効圧Ｐeが低い圧
縮リーンモード領域にも正圧域が存在するのは、圧縮リ
ーンモードでは希薄燃焼のために多量の吸入空気を導入
する結果、ターボチャージャ７の仕事量が同一であって
も大きな過給効果が得られるためである。On the other hand, the judgment values Ev0 and Pe0 are set on a line shown by a broken line based on the engine speed Ne in the stoichiometric mode region and the compression lean mode region in FIG. These determination values Ev0 and Pe0 are set in advance by a bench test of the engine 1, and the engine speed Ne is determined by the supercharging effect of the turbocharger 7.
Further, the pressure in the surge tank 4 is set to a boundary (that is, the atmospheric pressure) at which the pressure in the surge tank 4 changes from a negative pressure to a positive pressure as the target average effective pressure Pe increases. This solves the problem described above. Here, the positive pressure region also exists in the compression lean mode region where the engine speed Ne and the target average effective pressure Pe are lower than the negative pressure region in the stoichiometric mode region because a large amount of intake air is generated due to lean combustion in the compression lean mode. This is because as a result of introducing air, a large supercharging effect can be obtained even if the work of the turbocharger 7 is the same.
【００２７】従って、図２に示すように、ストイキモー
ドの負圧域と圧縮リーンモードの正圧域とが隣接するこ
とになり、両モード間の切換時には、その境界でサージ
タンク４内の圧力が急変することになる。ここで、上記
のようにストイキモードの負圧域では（Ｅv≦Ｅv0）、
ＥＧＲ切換バルブ１５が第１ＥＧＲ通路１３側に切換え
られて（ステップＳ２２）、近接触媒１１の下流側が第
１ＥＧＲ通路１３及び共用通路１６を介してサージタン
ク４側と接続される。上記のように近接触媒１１の下流
側の排ガス圧力は低いものの、大気圧よりは高いことか
ら、負圧であるサージタンク４側との間にＥＧＲ還流の
ための差圧が確保され、排ガスがサージタンク４側に還
流されて、燃焼温度の低下によりＮＯｘ排出量の低減が
達成される。そして、このときの排ガスは煤含有量が非
常に低いため、吸気系（サージタンクやインテークマニ
ホールド）へのカーボンの堆積が抑制されて、これによ
るトラブルが防止される。Therefore, as shown in FIG. 2, the negative pressure region in the stoichiometric mode and the positive pressure region in the compression lean mode are adjacent to each other. Will suddenly change. Here, as described above, in the negative pressure range of the stoichiometric mode (Ev ≦ Ev0),
The EGR switching valve 15 is switched to the first EGR passage 13 (step S22), and the downstream side of the proximity catalyst 11 is connected to the surge tank 4 via the first EGR passage 13 and the common passage 16. Although the exhaust gas pressure on the downstream side of the proximity catalyst 11 is lower than the atmospheric pressure as described above, a differential pressure for the EGR recirculation between the negative pressure and the surge tank 4 side is ensured. It is recirculated to the surge tank 4 side, and a reduction in NOx emission is achieved by a decrease in combustion temperature. Since the exhaust gas at this time has a very low soot content, the accumulation of carbon in the intake system (surge tank or intake manifold) is suppressed, and troubles due to this are prevented.
【００２８】一方、圧縮リーンモードの正圧域では（Ｐ
e＞Ｐe0）、ＥＧＲ切換バルブ１５が第２ＥＧＲ通路１
４側に切換えられ（ステップＳ３０）、排気タービン７
ｂの上流側が第２ＥＧＲ通路１４及び共用通路１６を介
してサージタンク４側と接続される。上記のように排気
タービン７ｂの上流側は正圧のサージタンク４以上の圧
力を有することから、このようなターボチャージャ７の
過給効果が高い運転状態であってもＥＧＲ還流のための
差圧が確保され、必要量のＥＧＲが確実に還流されてＮ
Ｏｘ排出量が低減される。On the other hand, in the positive pressure range in the compression lean mode, (P
e> Pe0), the EGR switching valve 15 is connected to the second EGR passage 1
4 (step S30), and the exhaust turbine 7
The upstream side of b is connected to the surge tank 4 via the second EGR passage 14 and the common passage 16. Since the upstream side of the exhaust turbine 7b has a pressure equal to or higher than the positive pressure surge tank 4 as described above, even when the turbocharger 7 is in an operation state in which the supercharging effect is high, the differential pressure for the EGR recirculation is high. And the required amount of EGR is reliably recirculated to
Ox emissions are reduced.
【００２９】そして、以上のＥＧＲ通路１３，１４の切
換は、ステップＳ１２の判定に基づいて燃料噴射モード
の切換に同期して行われることから、モード切換に伴っ
てターボチャージャ７の過給効果が増減してサージタン
ク４の圧力が急変しても、常に必要量のＥＧＲを確実に
還流可能となる。しかも、サージタンク４側が負圧でＥ
ＧＲ還流のための差圧を確保し易いストイキモードの負
圧域では、近接触媒１１の下流側の排ガス、つまり、近
接触媒１１により煤をトラップされた煤含有量の低い排
ガスを還流させることから、吸気系へのカーボンの堆積
を抑制可能となる。Since the switching of the EGR passages 13 and 14 is performed in synchronization with the switching of the fuel injection mode based on the determination in step S12, the supercharging effect of the turbocharger 7 is reduced with the mode switching. Even if the pressure of the surge tank 4 changes suddenly due to the increase or decrease, the required amount of EGR can always be reliably recirculated. In addition, the surge tank 4 side is negative pressure and E
In the negative pressure range of the stoichiometric mode in which it is easy to secure the differential pressure for the GR recirculation, the exhaust gas on the downstream side of the proximity catalyst 11, that is, the exhaust gas having a low soot content in which soot is trapped by the proximity catalyst 11 is recirculated. In addition, it is possible to suppress carbon deposition on the intake system.
【００３０】尚、ＥＧＲ通路１３，１４の切換は各燃料
噴射モード内においても行われ、例えばストイキモード
の負圧域から正圧域に運転状態が移行して（Ｅv＞Ｅv
0）、ＥＧＲ還流のための差圧を確保し難くなると、第
１ＥＧＲ通路１３から第２ＥＧＲ通路１４側に切換えら
れて、排気タービン７ｂの上流側の高い圧力の排ガスが
還流される。又、圧縮リーンモードの正圧域から負圧域
に運転状態が移行して（Ｐe≦Ｐe0）、ＥＧＲ還流のた
めの差圧を確保し易くなると、第２ＥＧＲ通路１４から
第１ＥＧＲ通路１３に切換えられて、近接触媒１１の下
流側の煤含有量の低い排ガスが還流される。The switching of the EGR passages 13 and 14 is also performed in each fuel injection mode. For example, the operating state shifts from the negative pressure range to the positive pressure range in the stoichiometric mode (Ev> Ev).
0) When it becomes difficult to secure a differential pressure for EGR recirculation, the first EGR passage 13 is switched to the second EGR passage 14 side, and high-pressure exhaust gas upstream of the exhaust turbine 7b is recirculated. Further, when the operating state shifts from the positive pressure range to the negative pressure range in the compression lean mode (Pe ≦ Pe0) and it becomes easy to secure a differential pressure for EGR recirculation, the second EGR passage 14 is switched to the first EGR passage 13. Thus, the exhaust gas having a low soot content downstream of the proximity catalyst 11 is recirculated.
【００３１】以上のように本実施形態のターボチャージ
ャ付きエンジンのＥＧＲ制御装置では、ストイキモード
と圧縮リーンモードとの間で燃焼噴射モードを切換えた
ときに、これと同期してＥＧＲ通路１３，１４を切換え
ている。よって、モード切換に伴ってターボチャージャ
７の過給効果が増減してサージタンク４の圧力が急変し
ても、それに応じた適切な圧力の排ガスを還流させて、
常に必要量のＥＧＲを確実に還流させてＮＯｘ低減を達
成することができる。As described above, in the EGR control device for a turbocharged engine according to the present embodiment, when the combustion injection mode is switched between the stoichiometric mode and the compression lean mode, the EGR passages 13 and 14 are synchronized with this. Is switched. Therefore, even if the supercharging effect of the turbocharger 7 increases or decreases due to the mode switching and the pressure of the surge tank 4 changes suddenly, the exhaust gas of an appropriate pressure corresponding thereto is recirculated,
The required amount of EGR can always be reliably recirculated to achieve NOx reduction.
【００３２】しかも、ＥＧＲ還流のための差圧を確保し
易いストイキモードの負圧域及び圧縮リーンモードの負
圧域では、近接触媒１１の下流側から煤含有量の低い排
ガスを還流させているため、吸気系へのカーボンの堆積
を抑制してトラブルを未然に防止することができる。以
上で実施形態の説明を終えるが、本発明の態様はこの実
施形態に限定されるものではない。例えば、上記実施形
態では筒内噴射型エンジン１用のＥＧＲ制御装置として
具体化したが、その対象はこれに限らず、運転状態に応
じて燃焼モードを切換可能なエンジンであれば適用可能
である。従って、例えば通常の吸気管内に燃料噴射する
吸気管噴射型エンジンで、ストイキモードに加えてリー
ン空燃比でのリーンモードを実行するリーンバーンエン
ジン用のＥＧＲ制御装置に具体化してもよい。Further, in the negative pressure range of the stoichiometric mode and the negative pressure range of the compression lean mode in which the differential pressure for EGR recirculation is easily ensured, the exhaust gas having a low soot content is recirculated from the downstream side of the proximity catalyst 11. Therefore, it is possible to suppress the accumulation of carbon in the intake system and prevent a trouble before it occurs. The description of the embodiment is finished above, but aspects of the present invention are not limited to this embodiment. For example, in the above-described embodiment, the EGR control device for the in-cylinder injection engine 1 is embodied. However, the present invention is not limited to this, and is applicable to any engine that can switch the combustion mode according to the operating state. . Therefore, for example, the present invention may be embodied as an EGR control device for a lean burn engine that executes a lean mode at a lean air-fuel ratio in addition to a stoichiometric mode in an intake pipe injection engine that injects fuel into a normal intake pipe.
【００３３】又、上記実施形態では、燃料噴射モードの
切換に完全に同期してＥＧＲ通路１３，１４を切換えた
が、本発明はこれに限定されず、モード切換に対してＥ
ＧＲ通路１３，１４の切換タイミングをずらして、モー
ド切換時の吸気圧の変化に一致させてもよく、この場合
には、より一層ＥＧＲを確実に導入することができる。
詳細には、リーンモードからストイキモードへの切換時
であれば、モード切換よりもＥＧＲ通路１３，１４の切
換タイミングを所定時間遅らせ、ストイキモードからリ
ーンモードへの切換時であれば、モード切換に対してＥ
ＧＲ通路１３，１４の切換を即時に実行し、これによ
り、吸気圧変化の遅れに対してＥＧＲ通路１３，１４を
確実に切換えることができる。又、ＥＧＲ通路１３，１
４の切換に伴ってサージタンク４側に還流されるガスが
実際に変更されるには、若干の応答遅れがあるため、燃
料噴射モードの切換に対して僅かに先行してＥＧＲ通路
１３、１４を切換えるようにしてもよい。本発明は、こ
れらのような制御態様も含むものとする。In the above-described embodiment, the EGR passages 13 and 14 are switched completely in synchronization with the switching of the fuel injection mode. However, the present invention is not limited to this.
The switching timing of the GR passages 13 and 14 may be shifted to match the change in intake pressure at the time of mode switching, and in this case, EGR can be more reliably introduced.
More specifically, when switching from the lean mode to the stoichiometric mode, the switching timing of the EGR passages 13 and 14 is delayed by a predetermined time from the mode switching, and when switching from the stoichiometric mode to the lean mode, the mode switching is performed. For E
The switching of the GR passages 13 and 14 is performed immediately, whereby the switching of the EGR passages 13 and 14 can be reliably performed in response to a delay in the change in intake pressure. Also, the EGR passages 13, 1
Since the gas recirculated to the surge tank 4 is actually changed with the switching of the fuel injection mode 4, there is a slight response delay, so that the EGR passages 13, 14 slightly precede the switching of the fuel injection mode. May be switched. The present invention includes such control modes.
【００３４】[0034]
【発明の効果】以上説明したように本発明のターボチャ
ージャ付きエンジンのＥＧＲ制御装置によれば、燃焼モ
ードの切換に伴って吸気通路の圧力が急変しても、常に
必要量のＥＧＲを確実に還流させてＮＯｘ低減を達成で
き、しかも、排ガス中の煤による吸気系へのカーボン堆
積を抑制することができる。As described above, according to the EGR control apparatus for a turbocharged engine of the present invention, a required amount of EGR is always ensured even if the pressure in the intake passage changes suddenly with the switching of the combustion mode. It is possible to achieve NOx reduction by recirculation, and to suppress carbon deposition in the intake system due to soot in exhaust gas.
【図１】実施形態のターボチャージャ付きエンジンのＥ
ＧＲ制御装置を示す全体構成図である。FIG. 1 shows an E of a turbocharged engine according to an embodiment.
FIG. 2 is an overall configuration diagram showing a GR control device.
【図２】燃料噴射モード及び判定値Ｅv0，Ｐe0を設定す
るためのマップを示す説明図である。FIG. 2 is an explanatory diagram showing a map for setting a fuel injection mode and determination values Ev0 and Pe0.
【図３】ＥＣＵが実行するＥＧＲ制御ルーチンを示すフ
ローチャートである。FIG. 3 is a flowchart illustrating an EGR control routine executed by an ECU.
【図４】ＥＣＵが実行するＥＧＲ制御ルーチンを示すフ
ローチャートである。FIG. 4 is a flowchart illustrating an EGR control routine executed by an ECU.
１ エンジン ３ インテークマニホールド（吸気通路） ４ サージタンク（吸気通路） ５ 吸気管（吸気通路） ６ スロットルバルブ ７ ターボチャージャ ７ａ 吸気コンプレッサ ７ｂ 排気タービン １０ エキゾーストマニホールド（排気通路） １１ 近接触媒（排ガス浄化触媒） １２ 排気管（排気通路） １３ 第１ＥＧＲ通路 １４ 第２ＥＧＲ通路 １５ ＥＧＲ切換バルブ（通路切換手段） ２１ ＥＣＵ（制御手段） Reference Signs List 1 engine 3 intake manifold (intake passage) 4 surge tank (intake passage) 5 intake pipe (intake passage) 6 throttle valve 7 turbocharger 7a intake compressor 7b exhaust turbine 10 exhaust manifold (exhaust passage) 11 proximity catalyst (exhaust gas purification catalyst) 12 Exhaust pipe (exhaust passage) 13 First EGR passage 14 Second EGR passage 15 EGR switching valve (passage switching means) 21 ECU (control means)
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｆ０２Ｄ 21/08 ３１１ Ｆ０２Ｄ 21/08 ３１１Ｂ 23/00 23/00 Ｅ Ｊ 41/02 ３１０ 41/02 ３１０Ａ ３１０Ｄ ３１０Ｅ ３１０Ｆ 41/04 ３０５ 41/04 ３０５Ｂ ３１０ ３１０Ｂ 43/00 ３０１ 43/00 ３０１Ｋ ３０１Ｎ ３０１Ｒ ３０１Ｅ Ｆターム(参考） 3G005 EA16 FA35 GA02 GB16 GB24 GB28 GD11 GD16 GE00 GE09 HA02 HA04 HA12 HA18 JA24 JA36 JA39 JA45 JB02 3G062 AA05 BA02 EA10 ED01 ED03 ED11 FA02 FA05 GA01 GA06 GA17 3G084 AA04 BA05 BA07 BA09 BA13 BA17 BA20 CA04 DA10 EB08 EB12 EC03 FA07 FA10 FA29 FA33 3G092 AA01 AA06 AA09 AA17 AA18 BA05 BA06 BA07 DC09 DC10 DE03S DG07 EA06 EA07 EA11 EB05 FA17 HA01Z HD05Z HE01Z 3G301 HA01 HA04 HA11 HA13 HA16 JA25 KA11 LA03 LB04 MA01 MA12 MA18 NA06 NA07 NC02 NE14 NE15 PA01Z PA11Z PA16A PB03A PD02Z PE01Z PE09A PF03Z ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) F02D 21/08 311 F02D 21/08 311B 23/00 23/00 EJ 41/02 310 41/02 310A 310D 310E 310F 41/04 305 41/04 305B 310 310B 43/00 301 43/00 301K 301N 301R 301E F-term (reference) 3G005 EA16 FA35 GA02 GB16 GB24 GB28 GD11 GD16 GE00 GE09 HA02 HA04 HA12 HA18 JA24 JA36 JA39 JA45 JB02 3G06A BA02 EA10 ED01 ED03 ED11 FA02 FA05 GA01 GA06 GA17 3G084 AA04 BA05 BA07 BA09 BA13 BA17 BA20 CA04 DA10 EB08 EB12 EC03 FA07 FA10 FA29 FA33 3G092 AA01 AA06 AA09 AA17 AA18 BA05 BA06 BA07 DC09 DC10 DE03S01 DG07 HA04 HA11 HA13 HA16 JA25 KA11 LA03 LB04 MA01 MA12 MA18 NA06 NA07 NC02 NE14 NE15 PA01Z PA11Z PA16A PB03A PD02Z PE01Z PE09A PF03Z
Claims (1)
軸上に連結したターボチャージャを備えると共に、理論
空燃比より希薄側に空燃比を制御する第１燃焼モード
と、該第１燃焼モードより濃化側に空燃比を制御する第
２燃焼モードとを運転状態に応じて切換可能なエンジン
において、 上記排気タービンの下流側の排気通路に設けられた排ガ
ス浄化触媒と、 上記吸気コンプレッサの下流側の吸気通路に設けられた
スロットルバルブと、 上記排ガス浄化触媒の下流側の排気通路と上記スロット
ルバルブの下流側の吸気通路とを連通する第１ＥＧＲ通
路と、 上記排気タービンの上流側の排気通路と上記スロットル
バルブの下流側の吸気通路とを連通する第２ＥＧＲ通路
と、 上記第１ＥＧＲ通路と上記第２ＥＧＲ通路とを選択的に
開放する通路切換手段と、 少なくとも上記第１燃焼モードと上記第２燃焼モードと
の境界付近において、該第１燃焼モードの運転領域では
上記通路切換手段により上記第２ＥＧＲ通路を開放し、
該第２燃焼モードの運転領域では該通路切換手段により
上記第１ＥＧＲ通路を開放する制御手段とを備えたこと
を特徴とするターボチャージャ付きエンジンのＥＧＲ制
御装置。1. A first combustion mode in which an exhaust turbine and an intake compressor are coaxially connected to each other and the air-fuel ratio is controlled to be leaner than a stoichiometric air-fuel ratio, and a richer side than the first combustion mode. An exhaust gas purifying catalyst provided in an exhaust passage downstream of the exhaust turbine, and an intake passage downstream of the intake compressor. A first EGR passage communicating between an exhaust passage downstream of the exhaust gas purifying catalyst and an intake passage downstream of the throttle valve; an exhaust passage upstream of the exhaust turbine; and the throttle valve. A second EGR passage communicating with an intake passage downstream of the first EGR passage; and a passage selectively opening the first EGR passage and the second EGR passage. And switching means, in the vicinity of the boundary between at least the first combustion mode and the second combustion mode, the operating region of the first combustion mode to open the third 2EGR passage by the path switching means,
A control unit for opening the first EGR passage by the passage switching unit in the operation region of the second combustion mode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000382115A JP2002188522A (en) | 2000-12-15 | 2000-12-15 | Egr control device for engine with turbocharger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000382115A JP2002188522A (en) | 2000-12-15 | 2000-12-15 | Egr control device for engine with turbocharger |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002188522A true JP2002188522A (en) | 2002-07-05 |
Family
ID=18849999
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000382115A Withdrawn JP2002188522A (en) | 2000-12-15 | 2000-12-15 | Egr control device for engine with turbocharger |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002188522A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002276418A (en) * | 2001-03-23 | 2002-09-25 | Hitachi Ltd | Cylinder injection engine having turbo supercharger, and its control method |
| EP1420159A2 (en) * | 2002-11-15 | 2004-05-19 | Isuzu Motors Limited | EGR system for internal combustion engine provided with a turbo-charger |
| JP2005291210A (en) * | 2004-03-31 | 2005-10-20 | Inst Fr Petrole | Method of controlling recirculation of exhaust gas of internal combustion supercharged engine and engine using such method |
| EP1840348A1 (en) * | 2006-03-31 | 2007-10-03 | Mazda Motor Corporation | EGR System for Engine |
| US7389173B1 (en) * | 2007-03-27 | 2008-06-17 | Southwest Research Institute | Control system for an internal combustion engine operating with multiple combustion modes |
| US20140352298A1 (en) * | 2012-01-24 | 2014-12-04 | Toyota Jidosha Kabushiki Kaisha | Exhaust circulation apparatus for internal combustion engine |
| JP2019085982A (en) * | 2017-11-10 | 2019-06-06 | マツダ株式会社 | Control device of compression ignition type engine |
-
2000
- 2000-12-15 JP JP2000382115A patent/JP2002188522A/en not_active Withdrawn
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002276418A (en) * | 2001-03-23 | 2002-09-25 | Hitachi Ltd | Cylinder injection engine having turbo supercharger, and its control method |
| EP1420159A2 (en) * | 2002-11-15 | 2004-05-19 | Isuzu Motors Limited | EGR system for internal combustion engine provided with a turbo-charger |
| EP1420159A3 (en) * | 2002-11-15 | 2006-05-17 | Isuzu Motors Limited | EGR system for internal combustion engine provided with a turbo-charger |
| JP2005291210A (en) * | 2004-03-31 | 2005-10-20 | Inst Fr Petrole | Method of controlling recirculation of exhaust gas of internal combustion supercharged engine and engine using such method |
| EP1840348A1 (en) * | 2006-03-31 | 2007-10-03 | Mazda Motor Corporation | EGR System for Engine |
| US7389173B1 (en) * | 2007-03-27 | 2008-06-17 | Southwest Research Institute | Control system for an internal combustion engine operating with multiple combustion modes |
| US7565237B2 (en) | 2007-03-27 | 2009-07-21 | Southwest Research Institute | Control of in-cylinder conditions of an internal combustion engine operating with multiple combustion modes |
| US20140352298A1 (en) * | 2012-01-24 | 2014-12-04 | Toyota Jidosha Kabushiki Kaisha | Exhaust circulation apparatus for internal combustion engine |
| US9567945B2 (en) * | 2012-01-24 | 2017-02-14 | Toyota Jidosha Kabushiki Kaisha | Exhaust circulation apparatus for internal combustion engine |
| JP2019085982A (en) * | 2017-11-10 | 2019-06-06 | マツダ株式会社 | Control device of compression ignition type engine |
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| A300 | Withdrawal of application because of no request for examination |
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