JPH0914025A - Air-fuel ratio learning control device for internal combustion engine - Google Patents

Air-fuel ratio learning control device for internal combustion engine

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Publication number
JPH0914025A
JPH0914025A JP16029295A JP16029295A JPH0914025A JP H0914025 A JPH0914025 A JP H0914025A JP 16029295 A JP16029295 A JP 16029295A JP 16029295 A JP16029295 A JP 16029295A JP H0914025 A JPH0914025 A JP H0914025A
Authority
JP
Japan
Prior art keywords
correction coefficient
air
fuel ratio
learning
learning correction
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP16029295A
Other languages
Japanese (ja)
Inventor
Masanobu Osaki
正信 大崎
Seiichi Otani
精一 大谷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Unisia Automotive Ltd
Original Assignee
Unisia Jecs Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Unisia Jecs Corp filed Critical Unisia Jecs Corp
Priority to JP16029295A priority Critical patent/JPH0914025A/en
Publication of JPH0914025A publication Critical patent/JPH0914025A/en
Pending legal-status Critical Current

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

Abstract

PURPOSE: To prevent erroneous learning by measuring reversal frequency of the increment and decrement directions of an air-fuel ratio feedback correction factor after change of an area of engine operation state, and changing a deviation adding ratio with a learning correction factor update means, depending on the reversal frequency. CONSTITUTION: With a learning condition established, a deviation calculation means F computes a mean value of air-fuel feedback correction factors as well as deviation of the mean value from a reference value, from each saved value for an air-fuel ratio feedback correction factors at lean-rich reversal in an air-fuel ratio feedback correction factor setting means B. Thereafter, a reversal frequency measurement means H sets a reversal frequency at 1 or counts up a value, depending on whether an area of operation state changes from the previous reversal or not. Also an update ratio variable means I sets a relatively small value for an update ratio G (0<G<=1) depending on whether the reversal frequency is less than the preset value or above the value. In addition, a new learning correction factor with the ratio G for a deviation added to a learning correction factor for an area of current engine operation state is written on a learning correction factor map via a learning correction factor update means G.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、内燃機関の空燃比学習
制御装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-fuel ratio learning control system for an internal combustion engine.

【０００２】[0002]

【従来の技術】従来から、空燃比フィードバック制御機
能をもつ内燃機関の燃料供給装置（電子制御燃料噴射装
置）においては、特開昭６１−１９０１４１号公報や特
公平４−７５３８３号公報に示されているような空燃比
学習制御装置が採用されている。2. Description of the Related Art Conventionally, a fuel supply device (electronically controlled fuel injection device) for an internal combustion engine having an air-fuel ratio feedback control function is disclosed in Japanese Patent Laid-Open No. 61-190141 and Japanese Patent Publication No. 4-75383. Such an air-fuel ratio learning control device is adopted.

【０００３】これは、機関に吸入される空気量に関与す
るパラメータ（例えば機関吸入空気流量及び機関回転
数）から算出される基本燃料噴射量と、空燃比センサか
らの信号に基づいて積分制御などにより設定される空燃
比フィードバック補正係数とから、燃料噴射量を演算
し、空燃比を目標空燃比にフィードバック制御するもの
において、空燃比フィードバック制御中の空燃比フィー
ドバック補正係数の平均値の基準値からの偏差を予め定
めた機関運転状態のエリア別に学習して学習補正係数を
定め、燃料噴射量の演算にあたって、基本燃料噴射量を
学習補正係数により補正して、空燃比フィードバック補
正係数なしで得られるベース空燃比を目標空燃比にでき
る限り一致させるようにしたものである。This is based on a basic fuel injection amount calculated from parameters related to the amount of air taken into the engine (for example, engine intake air flow rate and engine speed), and integral control based on a signal from the air-fuel ratio sensor. From the reference value of the average value of the air-fuel ratio feedback correction coefficient during the air-fuel ratio feedback control, in which the fuel injection amount is calculated from the air-fuel ratio feedback correction coefficient set by Deviation is learned for each predetermined area of the engine operating state to determine a learning correction coefficient, and when calculating the fuel injection amount, the basic fuel injection amount is corrected by the learning correction coefficient and obtained without the air-fuel ratio feedback correction coefficient. The base air-fuel ratio is made to match the target air-fuel ratio as much as possible.

【０００４】これによれば、過渡運転時における空燃比
フィードバック制御の追従遅れをなくすことができ、空
燃比フィードバック制御停止時においても所望の空燃比
を正確に得ることができる。ところが、機関運転状態の
エリアが変化した直後に、即、そのときの空燃比フィー
ドバック補正係数に基づいて学習補正係数の更新を行っ
てしまうと、エリア間のベース空燃比の段差により、
真の学習値（要求補正量）でなくなる、過渡運転で発
生した空燃比エラー（壁流燃料によるリッチ、エアフロ
ーメータ応答遅れによるリーン等）により、真の学習値
でなくなる、等の問題がある。According to this, it is possible to eliminate the follow-up delay of the air-fuel ratio feedback control during the transient operation, and it is possible to accurately obtain the desired air-fuel ratio even when the air-fuel ratio feedback control is stopped. However, immediately after the engine operating area changes, if the learning correction coefficient is updated immediately based on the air-fuel ratio feedback correction coefficient at that time, due to the step difference in the base air-fuel ratio between the areas,
There is a problem that the true learning value (required correction amount) is lost, the air-fuel ratio error (transient fuel rich, lean due to air flow meter response delay, etc.) that occurred in the transient operation causes the true learning value to be lost.

【０００５】そこで、前記公報に記載の空燃比学習制御
装置では、実際の機関運転状態が予め定めた機関運転状
態のエリアのうち任意の１つのエリアに継続してあると
きの空燃比フィードバック補正係数の増減方向の反転回
数（空燃比センサ出力の反転回数）を計測し、その反転
回数が所定値未満の場合は学習（学習補正係数の更新）
を禁止し、所定値以上になって安定してから学習を開始
するようにしている。Therefore, in the air-fuel ratio learning control device described in the above publication, the air-fuel ratio feedback correction coefficient when the actual engine operating state continues in any one of the predetermined engine operating state areas. Measure the number of reversals in the increasing / decreasing direction (the number of reversals of the air-fuel ratio sensor output), and learn if the number of reversals is less than the specified value (update the learning correction coefficient)
Is prohibited, and learning is started after the value becomes equal to or more than a predetermined value and becomes stable.

【０００６】[0006]

【発明が解決しようとする課題】しかしながら、このよ
うな従来の内燃機関の空燃比学習制御装置にあっては、
機関運転状態のエリアが定まった後、更に空燃比フィー
ドバック補正係数の増減方向が所定回以上反転してか
ら、学習を開始していたため、誤学習を防止できる反
面、学習の機会が少なくなって、学習の進行が遅れた
り、未学習領域が残ることにより、十分な学習制御がな
されないことがあるという問題点があった。However, in such a conventional air-fuel ratio learning control apparatus for an internal combustion engine,
Since the learning was started after the increase / decrease direction of the air-fuel ratio feedback correction coefficient was reversed more than a predetermined number of times after the area of the engine operating state was determined, erroneous learning can be prevented, but learning opportunities are reduced. There is a problem that sufficient learning control may not be performed due to delay of learning progress or remaining unlearned area.

【０００７】本発明は、このような従来の問題点に鑑
み、誤学習の防止と学習機会の確保とを高い次元で両立
させて、より良好な学習制御がなされるようにすること
を目的とする。In view of such conventional problems, it is an object of the present invention to realize prevention of erroneous learning and securing of a learning opportunity at a high level so that better learning control can be performed. To do.

【０００８】[0008]

【課題を解決するための手段】このため、請求項１に係
る発明では、図１に示すように、機関に吸入される空気
量に応じた基本燃料噴射量を演算する基本燃料噴射量演
算手段（Ａ）と、空燃比センサにより検出される空燃比
のリーン・リッチに応じて空燃比フィードバック補正係
数を増減して設定する空燃比フィードバック補正係数設
定手段（Ｂ）と、機関運転状態のエリア毎に学習補正係
数を記憶する書換え可能な学習補正係数記憶手段（Ｃ）
と、この学習補正係数記憶手段から現在の機関運転状態
のエリアに対応する学習補正係数を検索する学習補正係
数検索手段（Ｄ）と、前記基本燃料噴射量と前記空燃比
フィードバック補正係数と前記学習補正係数とから燃料
噴射弁による燃料噴射量を演算する燃料噴射量演算手段
（Ｅ）と、空燃比フィードバック補正係数の増減方向が
反転する毎に、現在の空燃比フィードバック補正係数の
平均値の基準値からの偏差を算出する偏差算出手段
（Ｆ）と、現在の学習補正係数に前記偏差の所定割合を
加算して、新たな学習補正係数を設定し、前記学習補正
係数記憶手段における現在の機関運転状態のエリアに対
応する学習補正係数のデータを書換える学習補正係数更
新手段（Ｇ）と、を備える内燃機関の空燃比学習制御装
置において、下記（Ｈ）及び（Ｉ）の手段を設ける構成
とする。Therefore, in the invention according to claim 1, as shown in FIG. 1, basic fuel injection amount calculation means for calculating the basic fuel injection amount according to the amount of air taken into the engine. (A), air-fuel ratio feedback correction coefficient setting means (B) for increasing / decreasing the air-fuel ratio feedback correction coefficient according to lean / rich of the air-fuel ratio detected by the air-fuel ratio sensor, and for each area of engine operating state Rewritable learning correction coefficient storage means (C) for storing the learning correction coefficient in the
And a learning correction coefficient retrieving means (D) for retrieving a learning correction coefficient corresponding to the area of the current engine operating state from the learning correction coefficient storage means, the basic fuel injection amount, the air-fuel ratio feedback correction coefficient, and the learning. Fuel injection amount calculation means (E) for calculating the fuel injection amount by the fuel injection valve from the correction coefficient, and a reference for the average value of the current air-fuel ratio feedback correction coefficient each time the increase / decrease direction of the air-fuel ratio feedback correction coefficient is reversed. A deviation calculation means (F) for calculating a deviation from the value, a new learning correction coefficient is set by adding a predetermined ratio of the deviation to the current learning correction coefficient, and the current engine in the learning correction coefficient storage means is set. In an air-fuel ratio learning control device for an internal combustion engine, which comprises learning correction coefficient updating means (G) for rewriting the data of the learning correction coefficient corresponding to the operating state area, the following (H And the configuration of providing the means of (I).

【０００９】（Ｈ）実際の機関運転状態が前記学習補正
係数記憶手段が定める機関運転状態のエリアのうち任意
の１つのエリアに継続してあるときの空燃比フィードバ
ック補正係数の増減方向の反転回数を計測する反転回数
計測手段 （Ｉ）前記反転回数に応じて前記学習補正係数更新手段
における前記偏差を加算する割合を変更する更新割合可
変手段 請求項２に係る発明では、前記更新割合可変手段（Ｉ）
は、前記反転回数が所定値未満のときに前記学習補正係
数更新手段における前記偏差を加算する割合を小さく
し、前記反転回数が所定値以上のときに前記偏差を加算
する割合を大きくするものであることを特徴とする。(H) The number of reversals in the increasing / decreasing direction of the air-fuel ratio feedback correction coefficient when the actual engine operation state continues in any one area of the engine operation state defined by the learning correction coefficient storage means. Inversion number measuring means for measuring (I) Update rate changing means for changing the rate of adding the deviation in the learning correction coefficient updating means according to the number of inversions. I)
Is to decrease the rate of adding the deviation in the learning correction coefficient updating means when the number of inversions is less than a predetermined value, and increase the rate of adding the deviation when the number of inversions is a predetermined value or more. It is characterized by being.

【００１０】請求項３に係る発明では、前記学習補正係
数更新手段（Ｇ）は、現在の学習補正係数をＫＢＬＲＣ
(old) 、現在の空燃比フィードバック補正係数の平均値
の基準値からの偏差をΔα、更新割合をＧ（０＜Ｇ≦
１）としたとき、新たな学習補正係数ＫＢＬＲＣ(new)
を、 ＫＢＬＲＣ(new) ＝ＫＢＬＲＣ(old) ＋Δα×Ｇ により、設定するものであることを特徴とする。In the invention according to claim 3, the learning correction coefficient updating means (G) sets the current learning correction coefficient to KBLRC.
(old) , the deviation of the current average value of the air-fuel ratio feedback correction coefficient from the reference value is Δα, and the update ratio is G (0 <G ≦
1), a new learning correction coefficient KBLRC (new)
Is set by KBLRC (new) = KBLRC (old) + Δα × G.

【００１１】[0011]

【作用】請求項１に係る発明では、機関運転状態のエリ
アが変化した後の、空燃比フィードバック補正係数の増
減方向の反転回数を計測し、この反転回数に応じて、学
習補正係数更新手段における前記偏差を加算する割合
（更新割合）を変更する。すなわち、反転回数が小さい
ときは機関運転状態のエリアが変化した直後であり、学
習の信頼性が低いため、更新割合を小さくして、誤学習
を防止しつつ、学習の機会を確保するのである。According to the first aspect of the invention, the number of reversals in the increasing / decreasing direction of the air-fuel ratio feedback correction coefficient after the area of the engine operating state is changed is measured, and the learning correction coefficient updating means is operated in accordance with the number of reversals. The rate at which the deviation is added (update rate) is changed. In other words, when the number of reversals is small, it is immediately after the engine operating area has changed, and the reliability of learning is low. Therefore, the update rate is reduced to prevent erroneous learning and secure an opportunity for learning. .

【００１２】請求項２に係る発明では、反転回数が所定
値未満のときに更新割合を小さくし、所定値以上のとき
に更新割合を大きくするように、２段階に制御する。請
求項３に係る発明では、学習補正係数を、ＫＢＬＲＣ
(new) ＝ＫＢＬＲＣ(o ld) ＋Δα×Ｇにより、更新し、
ここにおいて、更新割合Ｇを変化させることで、誤学習
を防止しつつ、学習の機会を確保する。According to the second aspect of the present invention, the update rate is decreased when the number of inversions is less than the predetermined value, and is increased when the number of times of inversion is greater than the predetermined value. In the invention according to claim 3, the learning correction coefficient is set to KBLRC.
(new) = KBLRC (old ) + updated by Δα × G,
Here, by changing the update ratio G, learning opportunities are secured while preventing erroneous learning.

【００１３】[0013]

【実施例】以下に本発明の一実施例を説明する。図２は
システム図である。機関１には、エアクリーナ２から吸
気ダクト３、スロットル弁４及び吸気マニホールド５を
介して空気が吸入される。吸気マニホールド５の各ブラ
ンチ部には燃料噴射弁６が設けられていて、燃料が噴射
供給される。機関１のシリンダ内で混合気は点火栓７に
より着火されて燃焼し、この燃焼により生じた排気は排
気通路８より排出される。An embodiment of the present invention will be described below. FIG. 2 is a system diagram. Air is sucked into the engine 1 from an air cleaner 2 through an intake duct 3, a throttle valve 4 and an intake manifold 5. Each branch of the intake manifold 5 is provided with a fuel injection valve 6 for injecting and supplying fuel. In the cylinder of the engine 1, the air-fuel mixture is ignited by the spark plug 7 and burned, and the exhaust gas generated by this combustion is discharged from the exhaust passage 8.

【００１４】前記燃料噴射弁６は、コントロールユニッ
ト10からの駆動パルス信号により通電されて開弁し、通
電停止されて閉弁する電磁式燃料噴射弁であって、駆動
パルス信号のパルス幅によって燃料噴射量が制御され、
この燃料噴射量の制御により空燃比が制御される。この
燃料噴射量の制御のため、コントロールユニット10には
エアフローメータ11、クランク角センサ12、空燃比セン
サ13等から信号が入力されている。The fuel injection valve 6 is an electromagnetic fuel injection valve that is energized by a drive pulse signal from the control unit 10 to open, and is deenergized to close the fuel. Injection quantity is controlled,
The air-fuel ratio is controlled by controlling the fuel injection amount. In order to control the fuel injection amount, signals are input to the control unit 10 from an air flow meter 11, a crank angle sensor 12, an air-fuel ratio sensor 13, and the like.

【００１５】エアフローメータ11は、吸気ダクト３に設
けられて、吸入空気流量Ｑを検出するものである。クラ
ンク角センサ12は、基準クランク角信号と単位クランク
角信号とを出力するもので、基準クランク角信号の周期
等から機関回転数Ｎを算出可能である。空燃比センサ13
は、排気通路８に設けられて、排気中の酸素濃度より機
関吸入混合気の空燃比（リーン・リッチ）を検出するも
のである。The air flow meter 11 is provided in the intake duct 3 and detects the intake air flow rate Q. The crank angle sensor 12 outputs a reference crank angle signal and a unit crank angle signal, and can calculate the engine speed N from the cycle of the reference crank angle signal and the like. Air-fuel ratio sensor 13
Is provided in the exhaust passage 8 and detects the air-fuel ratio (lean / rich) of the engine intake air-fuel mixture from the oxygen concentration in the exhaust gas.

【００１６】ここにおいて、コントロールユニット10に
内蔵のマイクロコンピュータは、図３〜図５に示すルー
チンを実行することにより、燃料噴射量Ｔｉを定め、こ
のＴｉに相当するパルス幅の駆動パルス信号を機関回転
に同期した所定のタイミングで燃料噴射弁６に出力し
て、燃料噴射を行わせる。図３は燃料噴射量演算ルーチ
ンであって、クランク角センサ12の基準クランク角信号
に同期して実行される。Here, the microcomputer incorporated in the control unit 10 determines the fuel injection amount Ti by executing the routines shown in FIGS. 3 to 5, and outputs a drive pulse signal having a pulse width corresponding to this Ti to the engine. The fuel is output to the fuel injection valve 6 at a predetermined timing synchronized with the rotation so that the fuel injection is performed. FIG. 3 is a fuel injection amount calculation routine, which is executed in synchronization with the reference crank angle signal of the crank angle sensor 12.

【００１７】ステップ１（図にはＳ１と記してある。以
下同様）では、エアフローメータ11からの信号に基づい
て検出される吸入空気流量Ｑと、クランク角センサ12か
らの信号に基づいて算出される機関回転数Ｎとから、機
関に吸入される空気量に対応する基本燃料噴射量Ｔｐ＝
Ｋ×Ｑ／Ｎ（Ｋは定数）を演算する。この部分が基本燃
料噴射量演算手段に相当する。In step 1 (denoted as S1 in the drawing, the same applies hereinafter), the intake air flow rate Q detected based on the signal from the air flow meter 11 and the signal from the crank angle sensor 12 are calculated. Based on the engine speed N, the basic fuel injection amount Tp =
K × Q / N (K is a constant) is calculated. This portion corresponds to the basic fuel injection amount calculation means.

【００１８】ステップ２では、後述する図４のルーチン
により設定されている空燃比フィードバック補正係数α
（基準値は１）を読込む。ステップ３では、学習補正係
数記憶手段として、マイクロコンピュータのＲＡＭ内
に、機関運転状態（Ｎ，Ｔｐ）のエリア別に学習補正係
数ＫＢＬＲＣを記憶させたマップから、現在の機関運転
状態（Ｎ，Ｔｐ）のエリアに対応する学習補正係数ＫＢ
ＬＲＣを検索する。この部分が学習補正係数検索手段に
相当する。At step 2, the air-fuel ratio feedback correction coefficient α set by the routine shown in FIG. 4 which will be described later.
Read (reference value is 1). In step 3, as the learning correction coefficient storage means, the current engine operation state (N, Tp) is obtained from a map in which the learning correction coefficient KBRRC is stored in the RAM of the microcomputer for each area of the engine operation state (N, Tp). Learning correction coefficient KB corresponding to the area of
Search LRC. This part corresponds to a learning correction coefficient search unit.

【００１９】学習補正係数ＫＢＬＲＣのマップについて
更に詳しく説明すれば、機関回転数Ｎを横軸、基本燃料
噴射量Ｔｐを縦軸とする例えば８×８のマップであり、
このマップの学習前のデータは全て０となっている。ま
た、このマップを記憶させる書換え可能なＲＡＭに対し
てはエンジンキースイッチのＯＦＦ後も記憶内容を保持
させるためバックアップ電源回路を接続してある。The map of the learning correction coefficient KBLRC will be described in more detail. For example, it is an 8 × 8 map in which the horizontal axis represents the engine speed N and the vertical axis represents the basic fuel injection amount Tp.
The data of this map before learning are all 0. Further, a backup power supply circuit is connected to the rewritable RAM for storing the map so as to retain the stored contents even after the engine key switch is turned off.

【００２０】ステップ４では、基本燃料噴射量Ｔｐと空
燃比フィードバック補正係数αと学習補正係数ＫＢＬＲ
Ｃとから、次式に従って、燃料噴射量Ｔｉを演算する。
この部分が燃料噴射量演算手段に相当する。 Ｔｉ＝Ｔｐ×（α＋ＫＢＬＲＣ） ステップ５では、演算された燃料噴射量Ｔｉを出力用レ
ジスタにセットする。これにより、機関回転に同期した
所定のタイミングでこのＴｉのパルス幅をもつ駆動パル
ス信号が燃料噴射弁６に出力されて、燃料噴射が行われ
る。In step 4, the basic fuel injection amount Tp, the air-fuel ratio feedback correction coefficient α, and the learning correction coefficient KBLR
From C, the fuel injection amount Ti is calculated according to the following equation.
This part corresponds to the fuel injection amount calculating means. Ti = Tp × (α + KBLRC) In step 5, the calculated fuel injection amount Ti is set in an output register. As a result, a drive pulse signal having the pulse width of Ti is output to the fuel injection valve 6 at a predetermined timing synchronized with the engine rotation, and fuel injection is performed.

【００２１】図４は空燃比フィードバック補正係数設定
ルーチンであって、所定時間毎に実行される。ステップ
11では、空燃比センサ13からの信号に基づいて空燃比の
リーン・リッチを判定する。空燃比がリーンの場合は、
ステップ12へ進んで前回リッチか否かを判定する。前回
リッチのときは、リッチ→リーンの反転時であるので、
ステップ13へ進んで空燃比フィードバック補正係数αを
前回値に対し所定の比例分Ｐ増大させる。そして、ステ
ップ14へ進んで、空燃比フィードバック補正係数αの平
均値の算出用データとして、このときの空燃比フィード
バック補正係数αをα1 として記憶保持した後、ステッ
プ15へ進んで、学習（図５の学習サブルーチン）を行
う。FIG. 4 shows an air-fuel ratio feedback correction coefficient setting routine, which is executed every predetermined time. Steps
At 11, the lean / rich of the air-fuel ratio is determined based on the signal from the air-fuel ratio sensor 13. If the air-fuel ratio is lean,
Proceeding to step 12, it is determined whether or not the previous time is rich. Since the last time of rich was the time of rich → lean reversal,
Proceeding to step 13, the air-fuel ratio feedback correction coefficient α is increased by a predetermined proportional amount P with respect to the previous value. Then, the routine proceeds to step 14, as calculation data of the average value of the air-fuel ratio feedback correction coefficient alpha, which is then stored holding the air-fuel ratio feedback correction coefficient alpha of this time as alpha 1, control proceeds to step 15, the learning (Fig. 5 learning subroutine).

【００２２】空燃比がリーンの場合で、前回もリーンの
ときは、ステップ16へ進んで空燃比フィードバック補正
係数αを前回値に対し所定の積分分Ｉ増大させる。尚、
Ｐ>>Ｉである。空燃比がリッチの場合は、ステップ17へ
進んで前回リーンか否かを判定する。前回リーンのとき
は、リーン→リッチの反転時であるので、ステップ18へ
進んで空燃比フィードバック補正係数αを前回値に対し
所定の比例分Ｐ減少させる。そして、ステップ19へ進ん
で、空燃比フィードバック補正係数αの平均値の算出用
データとして、このときの空燃比フィードバック補正係
数αをα2 として記憶保持した後、ステップ20へ進ん
で、学習（図５の学習サブルーチン）を行う。If the air-fuel ratio is lean and the air-fuel ratio is lean also last time, the routine proceeds to step 16, where the air-fuel ratio feedback correction coefficient α is increased by a predetermined integral amount I with respect to the previous value. still,
P >> I. If the air-fuel ratio is rich, the routine proceeds to step 17, where it is determined whether or not lean was the previous time. When the previous time is lean, it is the time of reversal of lean → rich, so the routine proceeds to step 18, and the air-fuel ratio feedback correction coefficient α is decreased by a predetermined proportional P with respect to the previous value. Then, the program proceeds to step 19, as calculation data of the average value of the air-fuel ratio feedback correction coefficient alpha, after the air-fuel ratio feedback correction coefficient alpha in this case were stored and held as alpha 2, the program proceeds to step 20, the learning (Fig. 5 learning subroutine).

【００２３】空燃比がリッチの場合で、前回もリッチの
ときは、ステップ21へ進んで空燃比フィードバック補正
係数αを前回値に対し所定の積分分Ｉ減少させる。尚、
ステップ11，12，13，16，17，18，21の部分が空燃比フ
ィードバック補正係数設定手段に相当する。次に図５の
学習サブルーチンについて、図６をあわせて参照しつ
つ、説明する。If the air-fuel ratio is rich and the previous time is also rich, the routine proceeds to step 21, where the air-fuel ratio feedback correction coefficient α is decreased by a predetermined integral amount I from the previous value. still,
Steps 11, 12, 13, 16, 17, 18, and 21 correspond to the air-fuel ratio feedback correction coefficient setting means. Next, the learning subroutine of FIG. 5 will be described with reference to FIG.

【００２４】ステップ31では、所定の学習条件が成立し
ているか否かを判定する。ここで、学習条件とは、例え
ば、機関冷却水温が所定値以上（暖機完了後）、空燃比
センサの反転周波数が所定値以上（活性状態）、及び、
空燃比フィードバック制御中であることである。学習条
件の不成立時は学習を行うことなく本サブルーチンを終
了し、成立時にのみステップ32以降へ進む。At step 31, it is judged whether or not a predetermined learning condition is satisfied. Here, the learning conditions include, for example, the engine cooling water temperature equal to or higher than a predetermined value (after completion of warming up), the inversion frequency of the air-fuel ratio sensor is equal to or higher than a predetermined value (active state), and
That is, the air-fuel ratio feedback control is being performed. When the learning condition is not satisfied, this subroutine is terminated without learning, and only when it is satisfied, the process proceeds to step 32 and thereafter.

【００２５】ステップ32では、リッチ→リーンの反転時
の空燃比フィードバック補正係数の最新の記憶値α
1 と、リーン→リッチの反転時の空燃比フィードバック
補正係数の最新の記憶値α2 とから、空燃比フィードバ
ック補正係数の平均値αAVE ＝（α1 ＋α2 ）／２を算
出する。ステップ33では、空燃比フィードバック補正係
数の平均値αAVE の基準値（１）からの偏差Δα＝α
AVE −１を算出する。ステップ32，33の部分が偏差算出
手段に相当する。In step 32, the latest stored value α of the air-fuel ratio feedback correction coefficient at the time of reversal of rich → lean
The average value of the air-fuel ratio feedback correction coefficient α AVE = (α 1 + α 2 ) / 2 is calculated from 1 and the latest stored value α 2 of the air-fuel ratio feedback correction coefficient at the time of the lean → rich inversion. In step 33, the deviation Δα = α of the average value α AVE of the air-fuel ratio feedback correction coefficient from the reference value (1)
AVE- 1 is calculated. The steps 32 and 33 correspond to deviation calculating means.

【００２６】ステップ34では、今回の反転時の実際の機
関運転状態に対応する学習補正係数マップ上の機関運転
状態（Ｎ，Ｔｐ）のエリアが前回の反転時と変化したか
否かを判定する。エリア変化有りの場合は、機関運転状
態（Ｎ，Ｔｐ）のエリアが変化した直後であるので、ス
テップ35で、空燃比フィードバック補正係数αの増減方
向の反転回数Ｃを１に設定する。エリア変化無しの場合
は、ステップ36で、空燃比フィードバック補正係数αの
増減方向の反転回数Ｃをカウントアップする。In step 34, it is determined whether or not the area of the engine operating state (N, Tp) on the learning correction coefficient map corresponding to the actual engine operating state at the time of this reversal has changed from the previous reversing. . In the case of the area change, it is immediately after the area of the engine operating state (N, Tp) has changed, so in step 35, the number C of reversals in the increasing / decreasing direction of the air-fuel ratio feedback correction coefficient α is set to 1. If there is no area change, in step 36, the number C of reversals in the increasing / decreasing direction of the air-fuel ratio feedback correction coefficient α is counted up.

【００２７】ここで、ステップ34〜36の部分が反転回数
計測手段に相当する。ステップ37では、反転回数Ｃが所
定値Ｃ0 （例えば２）以上か否かを判定する。反転回数
Ｃが所定値Ｃ0 未満、例えばＣ＝１のときは、ステップ
38で、更新割合Ｇ（０＜Ｇ≦１）を、比較的小さな値Ｇ
1 に設定する。Here, the steps 34 to 36 correspond to the inversion number measuring means. In step 37, it is determined whether or not the inversion number C is a predetermined value C 0 (for example, 2) or more. If the number C of inversions is less than a predetermined value C 0 , for example C = 1,
At 38, the update ratio G (0 <G ≦ 1) is set to a relatively small value G.
Set to 1 .

【００２８】反転回数Ｃが所定値Ｃ0 以上、例えばＣ＝
２，３，４，…のときは、ステップ39で、更新割合Ｇ
（０＜Ｇ≦１）を、比較的大きな値Ｇ2 に設定する。こ
こで、ステップ37〜39の部分が更新割合可変手段に相当
する。尚、０＜Ｇ1＜Ｇ2 ≦１である。ステップ40で
は、次式のごとく、現在の機関運転状態（Ｎ，Ｔｐ）の
エリアに対応する学習補正係数ＫＢＬＲＣに前記偏差Δ
αの前記更新割合Ｇ分（Δα×Ｇ）を加算して、新たな
学習補正係数ＫＢＬＲＣを設定する。The number C of inversions is a predetermined value C 0 or more, for example C =
If 2, 3, 4, ..., In step 39, update rate G
(0 <G ≦ 1) is set to a relatively large value G 2 . Here, the part of steps 37 to 39 corresponds to the update ratio changing means. In addition, 0 <G 1 <G 2 ≦ 1. In step 40, the deviation Δ is added to the learning correction coefficient KBLRC corresponding to the area of the current engine operating state (N, Tp) as shown in the following equation.
A new learning correction coefficient KBLRC is set by adding the update ratio G of α (Δα × G).

【００２９】ＫＢＬＲＣ＝ＫＢＬＲＣ＋Δα×Ｇ 従って、機関運転状態のエリアが変化した直後で、反転
回数Ｃが小さいときは、更新割合Ｇが比較的小さな値
（Ｇ＝Ｇ1 ）となるので、学習補正係数ＫＢＬＲＣの更
新度合が小さくなり、誤学習の防止と学習機会の確保と
を図ることができる。一方、反転回数Ｃが大きくなる
と、更新割合Ｇが比較的大きな値（Ｇ＝Ｇ2）となるの
で、学習補正係数ＫＢＬＲＣの更新度合が大きくなり、
十分な学習が可能となる。KBLRC = KBLRC + Δα × G Therefore, immediately after the engine operating area changes, when the number of reversals C is small, the update ratio G has a relatively small value (G = G 1 ), so the learning correction coefficient The update degree of KBLRC is reduced, and it is possible to prevent erroneous learning and secure learning opportunities. On the other hand, when the number C of inversions increases, the update rate G becomes a relatively large value (G = G 2 ), so the degree of update of the learning correction coefficient KBLRC increases,
Sufficient learning is possible.

【００３０】ステップ41では、こうして設定された新た
な学習補正係数ＫＢＬＲＣを学習補正係数マップにおけ
る現在の機関運転状態（Ｎ，Ｔｐ）のエリアに書込ん
で、データを書換える。ステップ40，41の部分が学習補
正係数更新手段に相当する。尚、フローチャート上では
省略したが、空燃比フィードバック制御停止条件におい
ては、空燃比フィードバック補正係数αを基準値又は前
回値にクランプし、このときは学習を行わないことは言
うまでもない。In step 41, the new learning correction coefficient KBLRC thus set is written in the area of the current engine operating state (N, Tp) in the learning correction coefficient map, and the data is rewritten. The steps 40 and 41 correspond to learning correction coefficient updating means. Although omitted in the flowchart, the air-fuel ratio feedback correction coefficient α is clamped to the reference value or the previous value under the air-fuel ratio feedback control stop condition, and it goes without saying that learning is not performed at this time.

【００３１】[0031]

【発明の効果】以上説明したように、請求項１に係る発
明によれば、機関運転状態のエリアが変化した後の空燃
比フィードバック補正係数の増減方向の反転回数に応じ
て、学習の更新割合を変更することにより、誤学習を防
止しつつ、学習の機会を確保することができるという効
果が得られる。As described above, according to the first aspect of the present invention, the learning update rate is determined according to the number of reversals in the increasing / decreasing direction of the air-fuel ratio feedback correction coefficient after the engine operating area has changed. By changing the, there is an effect that it is possible to secure an opportunity for learning while preventing erroneous learning.

【００３２】請求項２に係る発明によれば、反転回数が
所定値未満のときに更新割合を小さくし、所定値以上の
ときに更新割合を大きくすることで、２段階制御で必要
十分な効果が得られる。請求項３に係る発明によれば、
更新割合Ｇを変化させることで、誤学習を防止しつつ、
学習の機会を確保することができるという効果が得られ
る。According to the second aspect of the present invention, when the number of reversals is less than the predetermined value, the update rate is decreased, and when it is more than the predetermined value, the update rate is increased. Is obtained. According to the invention according to claim 3,
By changing the update rate G, while preventing erroneous learning,
The effect of being able to secure the opportunity for learning is obtained.

【図面の簡単な説明】[Brief description of the drawings]

【図１】 本発明の構成を示す機能ブロック図FIG. 1 is a functional block diagram showing a configuration of the present invention.

【図２】 本発明の一実施例を示すシステム図FIG. 2 is a system diagram showing an embodiment of the present invention.

【図３】 燃料噴射量演算ルーチンのフローチャートFIG. 3 is a flowchart of a fuel injection amount calculation routine.

【図４】 空燃比フィードバック補正係数設定ルーチン
のフローチャートFIG. 4 is a flowchart of an air-fuel ratio feedback correction coefficient setting routine.

【図５】 学習サブルーチンのフローチャートFIG. 5 is a flowchart of a learning subroutine.

【図６】 反転回数等の説明図FIG. 6 is an explanatory diagram of the number of times of inversion, etc.

【符号の説明】[Explanation of symbols]

１ 機関 ６ 燃料噴射弁 10 コントロールユニット 11 エアフローメータ 12 クランク角センサ 13 空燃比センサ 1 Engine 6 Fuel injection valve 10 Control unit 11 Air flow meter 12 Crank angle sensor 13 Air-fuel ratio sensor

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】機関に吸入される空気量に応じた基本燃料
噴射量を演算する基本燃料噴射量演算手段と、 空燃比センサにより検出される空燃比のリーン・リッチ
に応じて空燃比フィードバック補正係数を増減して設定
する空燃比フィードバック補正係数設定手段と、 機関運転状態のエリア毎に学習補正係数を記憶する書換
え可能な学習補正係数記憶手段と、 この学習補正係数記憶手段から現在の機関運転状態のエ
リアに対応する学習補正係数を検索する学習補正係数検
索手段と、 前記基本燃料噴射量と前記空燃比フィードバック補正係
数と前記学習補正係数とから燃料噴射弁による燃料噴射
量を演算する燃料噴射量演算手段と、 空燃比フィードバック補正係数の増減方向が反転する毎
に、現在の空燃比フィードバック補正係数の平均値の基
準値からの偏差を算出する偏差算出手段と、 現在の学習補正係数に前記偏差の所定割合を加算して、
新たな学習補正係数を設定し、前記学習補正係数記憶手
段における現在の機関運転状態のエリアに対応する学習
補正係数のデータを書換える学習補正係数更新手段と、 を備える内燃機関の空燃比学習制御装置において、 実際の機関運転状態が前記学習補正係数記憶手段が定め
る機関運転状態のエリアのうち任意の１つのエリアに継
続してあるときの空燃比フィードバック補正係数の増減
方向の反転回数を計測する反転回数計測手段と、 前記反転回数に応じて前記学習補正係数更新手段におけ
る前記偏差を加算する割合を変更する更新割合可変手段
と、 を設けたことを特徴とする内燃機関の空燃比学習制御装
置。1. A basic fuel injection amount calculation means for calculating a basic fuel injection amount according to the amount of air taken into the engine, and an air-fuel ratio feedback correction according to lean / rich of the air-fuel ratio detected by an air-fuel ratio sensor. Air-fuel ratio feedback correction coefficient setting means for increasing / decreasing the coefficient, rewritable learning correction coefficient storage means for storing the learning correction coefficient for each area of the engine operating state, and the current engine operation from the learning correction coefficient storage means. Learning correction coefficient search means for searching for a learning correction coefficient corresponding to a state area; and fuel injection for calculating a fuel injection quantity by a fuel injection valve from the basic fuel injection quantity, the air-fuel ratio feedback correction coefficient, and the learning correction coefficient. Every time the amount calculation means and the increasing / decreasing direction of the air-fuel ratio feedback correction coefficient are reversed, the current average value of the air-fuel ratio feedback correction coefficient A deviation calculating means for calculating the deviation from the value, by adding a predetermined proportion of the deviation in the current learning correction coefficient,
An air-fuel ratio learning control of an internal combustion engine, comprising: a learning correction coefficient updating means for setting a new learning correction coefficient and rewriting the learning correction coefficient data corresponding to the area of the current engine operating state in the learning correction coefficient storage means. In the apparatus, the number of times the air-fuel ratio feedback correction coefficient is reversed in the increasing / decreasing direction is measured when the actual engine operating state continues in any one of the engine operating state areas defined by the learning correction coefficient storage means. An air-fuel ratio learning control device for an internal combustion engine, comprising: an inversion number measuring unit; and an update ratio changing unit that changes an addition ratio of the deviation in the learning correction coefficient updating unit according to the inversion number. . 【請求項２】前記更新割合可変手段は、前記反転回数が
所定値未満のときに前記学習補正係数更新手段における
前記偏差を加算する割合を小さくし、前記反転回数が所
定値以上のときに前記偏差を加算する割合を大きくする
ものであることを特徴とする請求項１記載の内燃機関の
空燃比学習制御装置。2. The updating ratio changing means reduces a ratio of adding the deviation in the learning correction coefficient updating means when the number of inversions is less than a predetermined value, and when the number of inversions is a predetermined value or more, The air-fuel ratio learning control device for an internal combustion engine according to claim 1, wherein a ratio of adding the deviation is increased. 【請求項３】前記学習補正係数更新手段は、現在の学習
補正係数をＫＢＬＲＣ(old) 、現在の空燃比フィードバ
ック補正係数の平均値の基準値からの偏差をΔα、更新
割合をＧ（０＜Ｇ≦１）としたとき、新たな学習補正係
数ＫＢＬＲＣ(new) を、 ＫＢＬＲＣ(new) ＝ＫＢＬＲＣ(old) ＋Δα×Ｇ により、設定するものであることを特徴とする請求項１
又は請求項２記載の内燃機関の空燃比学習制御装置。3. The learning correction coefficient updating means is the current learning correction coefficient KBLRC (old) , the deviation of the current average value of the air-fuel ratio feedback correction coefficient from the reference value is Δα, and the update rate is G (0 < When G ≦ 1), a new learning correction coefficient KBLRC (new) is set by KBLRC (new) = KBLRC (old) + Δα × G.
Alternatively, the air-fuel ratio learning control device for the internal combustion engine according to claim 2.
JP16029295A 1995-06-27 1995-06-27 Air-fuel ratio learning control device for internal combustion engine Pending JPH0914025A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP16029295A JPH0914025A (en) 1995-06-27 1995-06-27 Air-fuel ratio learning control device for internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP16029295A JPH0914025A (en) 1995-06-27 1995-06-27 Air-fuel ratio learning control device for internal combustion engine

Publications (1)

Publication Number Publication Date
JPH0914025A true JPH0914025A (en) 1997-01-14

Family

ID=15711833

Family Applications (1)

Application Number Title Priority Date Filing Date
JP16029295A Pending JPH0914025A (en) 1995-06-27 1995-06-27 Air-fuel ratio learning control device for internal combustion engine

Country Status (1)

Country Link
JP (1) JPH0914025A (en)

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