JP2007247405A - Exhaust emission control device of internal combustion engine - Google Patents

Exhaust emission control device of internal combustion engine Download PDF

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JP2007247405A
JP2007247405A JP2006067564A JP2006067564A JP2007247405A JP 2007247405 A JP2007247405 A JP 2007247405A JP 2006067564 A JP2006067564 A JP 2006067564A JP 2006067564 A JP2006067564 A JP 2006067564A JP 2007247405 A JP2007247405 A JP 2007247405A
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fuel ratio
air
internal combustion
combustion engine
lean
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Tsuyoshi Ishikawa
剛志 石川
Tatsuo Sato
立男 佐藤
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Nissan Motor Co Ltd
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    • 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
    • Y02T10/40—Engine management systems

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  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To improve total exhaust emission control performance, by shortening catalyst activity as much as possible through lean forming control of the air-fuel ratio. <P>SOLUTION: From the start of air-fuel ratio feedback control, the target air-fuel ratio A/F is set to lean, and a lean forming degree is set on the basis of the starting time water temperature TWINT. Thus, an HC quantity exhausted from an engine (a combustion chamber) is reduced äFig.5(F)}, and at the same time, catalyst activity time can be shortened, while reducing the residual ratio of a catalyst, in its turn, an HC exhaust quantity from a tail pipe, with an increase in the combustion temperature, accordingly, the exhaust temperature and an increase in reaction heat with HC in the catalyst by surplus oxygen as factors äFig.5(G)}. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、排気浄化触媒を備えた内燃機関において、触媒の活性化を促進して排気浄化性能を改善する技術に関する。   The present invention relates to a technique for improving exhaust purification performance by promoting catalyst activation in an internal combustion engine equipped with an exhaust purification catalyst.

特許文献１には、始動直後に空燃比をリッチ化し、時間経過と共に空燃比を徐々にストイキ（理論空燃比）に収束させた後、ストイキでの空燃比フィードバック制御に移行することが開示されている。
特開２００１−２３４７７９号公報 Patent Document 1 discloses that the air-fuel ratio is enriched immediately after start-up, the air-fuel ratio is gradually converged to stoichiometric (theoretical air-fuel ratio) as time elapses, and then the control proceeds to stoichiometric air-fuel ratio feedback control. Yes.
JP 2001-23479A

しかしながら、空燃比がリッチもしくはストイキである場合、排気中の余剰酸素による触媒でのＨＣとの反応熱を期待できず、触媒活性時間を短縮できないため、トータルとして排気浄化性能が損なわれることがあった。
本発明は、このような従来の課題に着目してなされたもので、空燃比のリーン化制御により、触媒活性をできるだけ短縮し、トータルとして排気浄化性能を向上することを目的とする。 However, if the air-fuel ratio is rich or stoichiometric, the heat of reaction with HC in the catalyst due to excess oxygen in the exhaust gas cannot be expected, and the catalyst activation time cannot be shortened, so the exhaust purification performance may be impaired as a whole. It was.
The present invention has been made paying attention to such a conventional problem, and an object of the present invention is to reduce the catalyst activity as much as possible and to improve the exhaust purification performance as a whole by the lean air-fuel ratio control.

このため、本発明は、排気通路に排気浄化触媒を備えた内燃機関の排気浄化装置であって、
始動後、所定の空燃比フィードバック制御条件成立時に空燃比フィードバック制御を開始してから所定時間は、目標空燃比をリーンに設定する構成とした。 Therefore, the present invention is an exhaust purification device for an internal combustion engine provided with an exhaust purification catalyst in an exhaust passage,
After the start, the target air-fuel ratio is set to lean for a predetermined time after the air-fuel ratio feedback control is started when a predetermined air-fuel ratio feedback control condition is satisfied.

本発明によれば、空燃比フィードバック制御開始から目標空燃比を所定時間リーンに設定することにより、エンジン（燃焼室）から排出されるＨＣ（未燃燃料）を低減しつつ、触媒のＨＣ残存率ひいてはテールパイプからの最終的なＨＣ排出量（酸素ストレージ量）を低減すると同時に触媒活性を促進することができる。   According to the present invention, by setting the target air-fuel ratio to lean for a predetermined time from the start of air-fuel ratio feedback control, the HC remaining rate of the catalyst is reduced while reducing HC (unburned fuel) discharged from the engine (combustion chamber). As a result, the final HC emission amount (oxygen storage amount) from the tail pipe can be reduced, and at the same time, the catalyst activity can be promoted.

以下に本発明の実施の形態を図面に基づいて説明する。
図１は本発明の一実施形態を示すエンジン（内燃機関）のシステム図である。
エンジン１の各気筒の燃焼室には、エアクリーナ２から吸気ダクト３、スロットル弁４、吸気マニホールド５を経て空気が吸入される。吸気マニホールド５の各ブランチ部には各気筒毎に燃料噴射弁６が設けられている。但し、燃料噴射弁６は燃焼室内に直接臨ませる配置としてもよい。 Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a system diagram of an engine (internal combustion engine) showing an embodiment of the present invention.
Air is sucked into the combustion chamber of each cylinder of the engine 1 from the air cleaner 2 through the intake duct 3, the throttle valve 4, and the intake manifold 5. Each branch portion of the intake manifold 5 is provided with a fuel injection valve 6 for each cylinder. However, the fuel injection valve 6 may be disposed directly in the combustion chamber.

燃料噴射弁６は、ソレノイドに通電されて開弁し、通電停止されて閉弁する電磁式燃料噴射弁（インジェクタ）であって、後述するエンジンコントロールユニット（以下ＥＣＵという）１２からの駆動パルス信号により通電されて開弁し、図示しない燃料ポンプから圧送されてプレッシャレギュレータにより所定圧力に調整された燃料を噴射供給する。従って、駆動パルス信号のパルス幅により燃料噴射量が制御される。   The fuel injection valve 6 is an electromagnetic fuel injection valve (injector) that opens when the solenoid is energized and closes when the energization is stopped, and a drive pulse signal from an engine control unit (hereinafter referred to as ECU) 12 described later. The fuel is energized to open the valve, and the fuel is pumped from a fuel pump (not shown) and adjusted to a predetermined pressure by a pressure regulator. Therefore, the fuel injection amount is controlled by the pulse width of the drive pulse signal.

エンジン１の各燃焼室には点火プラグ７が設けられており、これにより火花点火して混合気を着火燃焼させる。
エンジン１の各燃焼室からの排気は、排気マニホールド８を介して排出される。また、排気マニホールド８からＥＧＲ通路９が導出され、これによりＥＧＲ弁１０を介して排気の一部を吸気マニホールド５に還流している。 Each combustion chamber of the engine 1 is provided with a spark plug 7, which sparks and ignites and burns the air-fuel mixture.
Exhaust gas from each combustion chamber of the engine 1 is discharged through an exhaust manifold 8. Further, an EGR passage 9 is led out from the exhaust manifold 8, whereby a part of the exhaust is recirculated to the intake manifold 5 via the EGR valve 10.

一方、排気通路には、排気マニホールド８の直下などに位置させて、排気浄化触媒１１が設けられている。
ＥＣＵ１２は、ＣＰＵ、ＲＯＭ、ＲＡＭ、Ａ／Ｄ変換器及び入出力インターフェイス等を含んで構成されるマイクロコンピュータを備え、各種センサからの入力信号を受け、後述のごとく演算処理して、燃料噴射弁６の作動を制御する。 On the other hand, an exhaust purification catalyst 11 is provided in the exhaust passage so as to be positioned immediately below the exhaust manifold 8.
The ECU 12 includes a microcomputer that includes a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like, receives input signals from various sensors, performs arithmetic processing as described later, and performs fuel injection. 6 is controlled.

前記各種センサとしては、エンジン１のクランク軸又はカム軸回転よりクランク角度と共にエンジン回転速度Ｎｅを検出可能なクランク角センサ１３、吸気ダクト３内で吸入空気量Ｑａを検出するエアフローメータ１４、スロットル弁４の開度ＴＶＯを検出するスロットルセンサ１５（スロットル弁４の全閉位置でＯＮとなるアイドルスイッチを含む）、エンジン１の冷却水温Ｔｗを検出する水温センサ１６、排気マニホールド８の集合部にて排気空燃比をリニアに検出できる広域型の空燃比センサ１７などが設けられている。ＥＣＵ１２には更にスタートスイッチ１８などからも信号が入力されている。   The various sensors include a crank angle sensor 13 that can detect the engine rotational speed Ne together with the crank angle based on the crankshaft or camshaft rotation of the engine 1, an air flow meter 14 that detects the intake air amount Qa in the intake duct 3, and a throttle valve. 4 includes a throttle sensor 15 (including an idle switch that is turned on when the throttle valve 4 is fully closed), a water temperature sensor 16 that detects the cooling water temperature Tw of the engine 1, and an exhaust manifold 8. A wide-range air-fuel ratio sensor 17 or the like that can detect the exhaust air-fuel ratio linearly is provided. A signal is also input to the ECU 12 from the start switch 18 and the like.

図２〜図４は、ＥＣＵ１２にて時間同期または回転同期で実行されるエンジン制御ルーチンのフローチャートである。本エンジン制御を、該フローチャートにしたがって、図５タイムチャートを参照しつつ説明する。
ステップＳ１では、スタートスイッチ１８がオンされたかを判定する。
スタートスイッチ１８がオンされたと判定されたときは、ステップＳ２へ進み、エンジン始動時の水温ＴＷＩＮＴを読み込む。 2 to 4 are flowcharts of an engine control routine executed by the ECU 12 in time synchronization or rotation synchronization. The engine control will be described according to the flowchart with reference to the time chart of FIG.
In step S1, it is determined whether the start switch 18 is turned on.
When it is determined that the start switch 18 is turned on, the process proceeds to step S2, and the water temperature TWINT at the time of engine start is read.

エンジン始動後、ステップＳ１でスタートスイッチ１８がオンからオフにされたと判定されたときはステップＳ３へ進み、前記始動時水温ＴＷＩＮＴが、目標空燃比リーン化の可能な設定水温範囲内−Ｌ≦ＴＷＩＮＴ≦Ｋにあるかを判定する。
設定水温範囲内にないと判定されたときは、目標空燃比リーン化による効果はないと判断し、ステップＳ４へ進んで始動時用の空燃比フィードフォワード制御を行う。 If it is determined in step S1 that the start switch 18 has been turned off after the engine is started, the process proceeds to step S3, where the starting water temperature TWINT is within a set water temperature range in which the target air-fuel ratio can be made lean -L ≦ TWINT. It is determined whether or not ≦ K.
If it is determined that it is not within the set water temperature range, it is determined that there is no effect of the target air-fuel ratio leaning, and the routine proceeds to step S4 where air-fuel ratio feedforward control for starting is performed.

始動時水温ＴＷＩＮＴが、設定範囲内にあると判定されたときはステップＳ５へ進み、空燃比フィードバック制御が開始されているかを判定し、開始前は、ステップＳ４へ進んで始動時用の水温等に応じた空燃比フィードフォワード制御を行う。なお、目標空燃比は初期設定のストイキに設定されているが、空燃比制御には機能しない{図５（Ｂ）のＡ部分}。   When it is determined that the starting water temperature TWINT is within the set range, the process proceeds to step S5, where it is determined whether the air-fuel ratio feedback control is started. Air-fuel ratio feedforward control according to The target air-fuel ratio is set to an initial stoichiometric value, but does not function for air-fuel ratio control {part A in FIG. 5B}.

空燃比フィードバック制御が開始されていると判定されたときは、ステップＳ６で前記始動時水温ＴＷＩＮＴに基づいて、目標空燃比リーンの設定値Ｃを決定する。
ステップＳ７では、触媒１１が活性温度に達しているかを判定する。この活性判断は、タイマーを設け、時間で判断する方法でもよい。
そして触媒１１が活性していないと判定されたときは、ステップＳ８で、現在の目標空燃比Ａ／Ｆが前記リーンの設定値Ｃ未満であるかを判定し、設定値Ｃ以下と判定された場合は、目標空燃比をストイキからリーンに徐々に移す制御に移行する{図５（Ｂ）のＢ部分}。 When it is determined that the air-fuel ratio feedback control has been started, the target air-fuel ratio lean set value C is determined based on the starting water temperature TWINT in step S6.
In step S7, it is determined whether the catalyst 11 has reached the activation temperature. This activity determination may be a method of determining by time by providing a timer.
When it is determined that the catalyst 11 is not active, it is determined in step S8 whether the current target air-fuel ratio A / F is less than the lean set value C, and is determined to be equal to or less than the set value C. In this case, the control shifts to a control for gradually shifting the target air-fuel ratio from stoichiometric to lean {B portion in FIG. 5B}.

具体的には、ステップＳ９で、目標空燃比Ａ／Ｆを、次式により設定する。
Ａ／Ｆ＝Ａ／Ｆｏ＋Ｔ１×ａ
Ａ／Ｆｏ；前回の目標空燃比
Ｔ１；目標空燃比Ａ／Ｆを計算するときの前回からの時間
ａ；単位時間Ｔ１当たりのＡ／Ｆ増減値
ステップＳ１０では、目標空燃比Ａ／Ｆから、点火時期補正量を算出する。具体的には、目標空燃比Ａ／Ｆの傾き{図５（Ｂ）のＢ部分}に合わせて点火時期を進角させるように算出する{図５（Ｄ）のＢ部分}。これにより、ストイキからリーンへの移行時の燃焼程度悪化を防止できる。 Specifically, in step S9, the target air-fuel ratio A / F is set by the following equation.
A / F = A / Fo + T1 × a
A / Fo; previous target air-fuel ratio T1; time from previous time when target air-fuel ratio A / F is calculated a; A / F increase / decrease value per unit time T1 In step S10, from target air-fuel ratio A / F, An ignition timing correction amount is calculated. Specifically, calculation is performed so that the ignition timing is advanced in accordance with the gradient of the target air-fuel ratio A / F {B portion in FIG. 5B} {B portion in FIG. 5D}. Thereby, the deterioration of the combustion degree at the time of the transition from stoichiometric to lean can be prevented.

ステップＳ１１では、前記目標空燃比Ａ／Ｆ及び点火時期から吸入空気量補正量を算出する。具体的には、目標空燃比のリーン化に合わせて空気量を増大させるように算出する{図５（Ｅ）のＢ部分}。これにより、Ａ／Ｆリーン化による回転落ちを防止できる。
目標空燃比Ａ／Ｆがリーン設定値Ｃになり水温が上がり始めると{図５（Ａ）のＣ部分}、燃焼安定度が良くなり点火時期の遅角化が可能となる。そこで、ステップＳ１２で目標空燃比Ａ／Ｆをリーン設定値Ｃに維持しつつ、ステップＳ１３で水温ＴＷＮを読込み、ステップＳ１４で上昇した水温に合わせて点火時期を遅角化し{図５（Ｄ）のＣ部分}、排温上昇につなげる。 In step S11, an intake air amount correction amount is calculated from the target air-fuel ratio A / F and ignition timing. Specifically, it is calculated so as to increase the air amount in accordance with the leaning of the target air-fuel ratio {B portion in FIG. 5 (E)}. Thereby, the fall of rotation by A / F leaning can be prevented.
When the target air-fuel ratio A / F reaches the lean set value C and the water temperature starts to rise {C portion in FIG. 5 (A)}, the combustion stability is improved and the ignition timing can be retarded. Therefore, while maintaining the target air-fuel ratio A / F at the lean set value C in step S12, the water temperature TWN is read in step S13, and the ignition timing is retarded in accordance with the water temperature increased in step S14 {FIG. C part}, leading to an increase in exhaust temperature.

点火時期遅角化によりトルク不足となり、そのままでは回転落ちを発生するため、ステップＳ１５へ進んで目標空燃比Ａ／Ｆと点火時期から不足空気量を算出し、回転落ち防止を行う{図５（Ｅ）のＣ部分}。
また、ステップＳ７で触媒が活性したと判定された場合は、目標空燃比をリーンからストイキに徐々に戻す制御に移行する。 Since the torque becomes insufficient due to the retarded ignition timing and the rotation is reduced as it is, the process proceeds to step S15 to calculate the insufficient air amount from the target air-fuel ratio A / F and the ignition timing to prevent the rotation from falling {FIG. E) C part}.
If it is determined in step S7 that the catalyst has been activated, the control shifts to gradually returning the target air-fuel ratio from lean to stoichiometric.

具体的には、ステップＳ１６で目標空燃比Ａ／Ｆを次式により設定する{図５（Ｂ）のＤ部分}。
Ａ／Ｆ＝Ａ／Ｆｏ＋Ｔ２×（−ａ）
Ａ／Ｆｏ；前回の目標空燃比（初期値＝Ｃ）
Ｔ２；目標空燃比Ａ／Ｆ（図示Ｄ部分）を計算するときの前回からの時間
−ａ；単位時間Ｔ２当たりのＡ／Ｆ増減値
ステップＳ１７では、目標空燃比Ａ／ＦがＦ（ストイキ空燃比）以下であるかを判定し、Ｆより大きいときには、ステップＳ１８へ進んで目標Ａ／Ｆから点火時期補正量を算出する。具体的には、目標空燃比Ａ／Ｆ{図５（Ｂ）のＤ部分}の傾きに合わせて点火時期を遅角させるように算出する{図５（Ｄ）のＤ部分}。これにより、リーンからストイキへの移行時の燃焼を良好に維持できる。 Specifically, in step S16, the target air-fuel ratio A / F is set by the following equation {D portion in FIG. 5B}.
A / F = A / Fo + T2 × (−a)
A / Fo: Previous target air-fuel ratio (initial value = C)
T2: Time from the previous time when calculating the target air-fuel ratio A / F (D portion in the figure) -a; A / F increase / decrease value per unit time T2 In step S17, the target air-fuel ratio A / F is F (stoichiometric air). It is determined whether or not the fuel ratio is less than F, and if it is greater than F, the routine proceeds to step S18 where the ignition timing correction amount is calculated from the target A / F. Specifically, calculation is performed so that the ignition timing is retarded in accordance with the inclination of the target air-fuel ratio A / F {D portion in FIG. 5B} {D portion in FIG. 5D}. Thereby, the combustion at the time of the transition from lean to stoichiometric can be favorably maintained.

次いで、ステップＳ１９へ進んで、前記目標空燃比Ａ／Ｆ及び点火時期から吸入空気量補正量を算出する。具体的には、目標空燃比のリッチ化に合わせて空気量を減少させるように算出する{図５（Ｅ）のＤ部分}。
ステップＳ１７で、目標空燃比Ａ／ＦがＦ以下であると判定されたときは、ステップＳ２０へ進んで、目標空燃比Ａ／ＦをＥにリッチ化し{図５（Ｂ）のＥ部分}、いわゆるリッチスパイク制御を行う。 Next, the routine proceeds to step S19, where the intake air amount correction amount is calculated from the target air-fuel ratio A / F and the ignition timing. Specifically, calculation is performed so as to decrease the air amount in accordance with the enrichment of the target air-fuel ratio {D portion in FIG. 5E}.
When it is determined in step S17 that the target air-fuel ratio A / F is equal to or less than F, the process proceeds to step S20 to enrich the target air-fuel ratio A / F to E {E portion in FIG. 5B}, So-called rich spike control is performed.

ステップＳ２１では、前記リッチスパイク制御の積算時間Ｔｅが、所定時間Ｔ３に達したかを判定し、達したときに、ステップＳ２２へ進んで通常の目標空燃比をストイキとする制御に戻す{図５（Ｂ）のＦ部分}。
リッチスパイク制御は、目標空燃比リーンからストイキに戻す際のＮＯｘ排出量の悪化を抑制するために行うが、実行時間が長すぎるとＨＣ排出量の悪化につながるため、適正に設定された所定時間Ｔ３でストイキに戻す。 In step S21, it is determined whether the integration time Te of the rich spike control has reached a predetermined time T3, and when it reaches, the process proceeds to step S22 to return to the control in which the normal target air-fuel ratio is stoichiometric {FIG. F part of (B)}.
The rich spike control is performed to suppress the deterioration of the NOx emission amount when returning from the target air-fuel ratio lean to the stoichiometric condition. However, if the execution time is too long, the HC emission amount will be deteriorated. Return to stoichiometric at T3.

以上のように、空燃比フィードバック制御開始から、目標空燃比Ａ／Ｆをリーンとすることにより、エンジン（燃焼室）から排出されるＨＣ量が低減されると同時に{図５（Ｆ）}、燃焼温度したがって排気温度の増大と、余剰酸素による触媒でのＨＣとの反応熱増大などを要因として触媒のＨＣ残存率ひいてはテールパイプからのＨＣ排出量を低減しつつ触媒活性時間を短縮することができる{図５（Ｇ）}。   As described above, by making the target air-fuel ratio A / F lean from the start of the air-fuel ratio feedback control, the amount of HC discharged from the engine (combustion chamber) is simultaneously reduced {FIG. 5 (F)}, The catalyst activation time can be shortened while reducing the HC residual rate of the catalyst and hence the HC emission amount from the tail pipe due to an increase in the combustion temperature and therefore the exhaust temperature and an increase in the reaction heat with HC due to excess oxygen. Yes {Fig. 5 (G)}.

また、目標空燃比Ａ／Ｆのリーン化の度合いを始動時水温ＴＷＩＮＴに基づいて設定することにより、水温が低いときはリーン化度合いを大きくし、水温が比較的高いときには、リーン化度合いを小さくすることで、運転性を維持しつつ水温に応じて必要なだけリーン化して触媒活性を早めることができる。
また、目標空燃比Ａ／Ｆをストイキからリーンに移行させ、リーンからストイキに戻す際は、所定時間をかけて徐々に変化させるため、運転性の悪化を抑制できる。 Further, by setting the degree of leaning of the target air-fuel ratio A / F based on the starting water temperature TWINT, the degree of leaning is increased when the water temperature is low, and the degree of leaning is decreased when the water temperature is relatively high. By doing so, the catalyst activity can be accelerated by leaning as much as necessary according to the water temperature while maintaining operability.
Further, when the target air-fuel ratio A / F is changed from stoichiometric to lean and returned from lean to stoichiometric, it is gradually changed over a predetermined time, so that deterioration of drivability can be suppressed.

同じく、リーン化制御時に点火時期を進角させて燃焼性悪化を防止し、空気量を増大することにより、エンジンの回転落ちを防止できる。また、上記のように燃焼性安定のため進角させた点火時期を、水温の上昇に伴い燃焼性が良化するに伴って遅角させることで、排気温度を上昇させ、触媒の活性を促進する。
なお、目標空燃比Ａ／Ｆリーン化により、触媒のＮＯｘ残存率が悪化し、テールパイプからのＮＯｘ排出量が増大するが、既述のように、目標空燃比リーン化を、触媒活性温度（水温で代表）若しくは時間で任意に設定できる制御とすることで、ＮＯｘの悪化を極力防止することができる。また、目標空燃比Ａ／Ｆをリーンからストイキに戻す際の触媒からのＮＯｘ排出量の悪化は、上記リッチスパイクを行うことで回避できる{図５（Ｈ）}。 Similarly, the ignition timing is advanced during lean control to prevent deterioration of combustibility, and the amount of air can be increased to prevent the engine from falling off. In addition, the ignition timing, which has been advanced to stabilize combustibility as described above, is retarded as the combustibility improves as the water temperature rises, thereby raising the exhaust temperature and promoting catalyst activity. To do.
The target air-fuel ratio A / F leaning deteriorates the NOx remaining rate of the catalyst and increases the NOx emission amount from the tail pipe. As described above, the target air-fuel ratio leaning is performed at the catalyst activation temperature ( By using control that can be arbitrarily set by time) or represented by time, it is possible to prevent NOx deterioration as much as possible. Further, the deterioration of the NOx emission amount from the catalyst when the target air-fuel ratio A / F is returned from lean to stoichiometric can be avoided by performing the rich spike {FIG. 5 (H)}.

本発明の一実施形態を示すエンジンのシステム図Engine system diagram showing an embodiment of the present invention 空燃比制御ルーチンのフローチャートAir-fuel ratio control routine flowchart 空燃比制御ルーチンのフローチャートAir-fuel ratio control routine flowchart 空燃比制御ルーチンのフローチャートAir-fuel ratio control routine flowchart 始動後の空燃比制御時における各種状態変化を示すタイムチャートTime chart showing various state changes during air-fuel ratio control after startup

符号の説明Explanation of symbols

１ エンジン
６ 燃料噴射弁
１２ ＥＣＵ
１７ Ｏ２センサ 1 engine
6 Fuel injection valve
12 ECU
17 O2 sensor

Claims (10)

排気通路に排気浄化触媒を備えた内燃機関の排気浄化装置であって、
始動後、所定の空燃比フィードバック制御条件成立時に空燃比フィードバック制御を開始してから所定時間は、目標空燃比をリーンに設定することを特徴とする内燃機関の排気浄化制御装置。 An exhaust gas purification apparatus for an internal combustion engine having an exhaust gas purification catalyst in an exhaust passage,
An exhaust gas purification control apparatus for an internal combustion engine, wherein after a start, a target air-fuel ratio is set to lean for a predetermined time after the air-fuel ratio feedback control is started when a predetermined air-fuel ratio feedback control condition is satisfied. 前記所定時間における目標空燃比のリーン度合いを、機関水温に応じて設定することを特徴とする請求項１に記載の内燃機関の排気浄化制御装置。   The exhaust gas purification control apparatus for an internal combustion engine according to claim 1, wherein the lean degree of the target air-fuel ratio in the predetermined time is set according to the engine water temperature. 前記所定時間経過後の空燃比フィードバック制御において、目標空燃比を変化させるときは、徐々に変化するように設定することを特徴とする請求項１または請求項２に記載の内燃機関の排気浄化制御装置。   3. The exhaust gas purification control for an internal combustion engine according to claim 1, wherein, in the air-fuel ratio feedback control after the predetermined time has elapsed, when the target air-fuel ratio is changed, the target air-fuel ratio is set to change gradually. apparatus. 前記所定時間をタイマーで計測することを特徴とする請求項１〜請求項３のいずれか１つに記載の内燃機関の排気浄化制御装置。   The exhaust gas purification control apparatus for an internal combustion engine according to any one of claims 1 to 3, wherein the predetermined time is measured by a timer. 前記所定時間の終了を、前記排気浄化触媒が活性されたときとして検出することを特徴とする請求項１〜請求項３のいずれか１つに記載の内燃機関の排気浄化制御装置。   The exhaust purification control device for an internal combustion engine according to any one of claims 1 to 3, wherein the end of the predetermined time is detected as a time when the exhaust purification catalyst is activated. 前記所定時間目標空燃比をリーンに設定した後、所定時間目標空燃比をリッチに設定することを特徴とする請求項１〜請求項５のいずれか１つに記載の内燃機関の排気浄化制御装置。   6. The exhaust gas purification control apparatus for an internal combustion engine according to claim 1, wherein the target air-fuel ratio is set to be rich for a predetermined time after the target air-fuel ratio is set to lean for the predetermined time. . 前記所定時間の目標空燃比のリーン設定時、該リーン度合いに応じて点火時期を設定することを特徴とする請求項１〜請求項６のいずれか１つに記載の内燃機関の排気浄化制御装置。   The exhaust gas purification control apparatus for an internal combustion engine according to any one of claims 1 to 6, wherein when the target air-fuel ratio is set to be lean for the predetermined time, the ignition timing is set in accordance with the lean degree. . 前記リーン度合いに応じた点火時期の変化代を、機関水温に応じて設定することを特徴とする請求項１〜請求項７のいずれか１つに記載の内燃機関の排気浄化制御装置。   The exhaust gas purification control device for an internal combustion engine according to any one of claims 1 to 7, wherein a change amount of the ignition timing according to the lean degree is set according to an engine water temperature. 前記所定時間における空燃比リーン制御は、吸入空気量を増大補正して行うことを特徴とする請求項１〜請求項８のいずれか１つに記載の内燃機関の排気浄化制御装置。   The exhaust gas purification control apparatus for an internal combustion engine according to any one of claims 1 to 8, wherein the air-fuel ratio lean control for the predetermined time is performed by increasing and correcting the intake air amount. 前記吸入空気量の増大補正量は、目標空燃比と点火時期に基づいて設定することを特徴とする請求項１〜請求項９のいずれか１つに記載の内燃機関の排気浄化制御装置。   The exhaust purification control apparatus for an internal combustion engine according to any one of claims 1 to 9, wherein the increase correction amount of the intake air amount is set based on a target air-fuel ratio and ignition timing.
JP2006067564A 2006-03-13 2006-03-13 Exhaust emission control device of internal combustion engine Pending JP2007247405A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015010592A (en) * 2013-07-02 2015-01-19 大阪瓦斯株式会社 Engine system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015010592A (en) * 2013-07-02 2015-01-19 大阪瓦斯株式会社 Engine system

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