JPS618438A - Method of controlling air-fuel ratio of internal combustion engine - Google Patents

Method of controlling air-fuel ratio of internal combustion engine

Info

Publication number
JPS618438A
JPS618438A JP12956884A JP12956884A JPS618438A JP S618438 A JPS618438 A JP S618438A JP 12956884 A JP12956884 A JP 12956884A JP 12956884 A JP12956884 A JP 12956884A JP S618438 A JPS618438 A JP S618438A
Authority
JP
Japan
Prior art keywords
air
fuel ratio
fuel
control
internal combustion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP12956884A
Other languages
Japanese (ja)
Inventor
Toshiyuki Takimoto
滝本 敏幸
Keiji Aoki
啓二 青木
Masaki Mitsuyasu
正記 光安
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.)
Toyota Motor Corp
Original Assignee
Toyota Motor 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 Toyota Motor Corp filed Critical Toyota Motor Corp
Priority to JP12956884A priority Critical patent/JPS618438A/en
Publication of JPS618438A publication Critical patent/JPS618438A/en
Pending legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/02Circuit arrangements for generating control signals
    • F02D41/14Introducing closed-loop corrections
    • F02D41/1438Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1473Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method
    • F02D41/1474Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the regulation method by detecting the commutation time of the sensor
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/02Circuit arrangements for generating control signals
    • F02D41/14Introducing closed-loop corrections
    • F02D41/1438Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
    • F02D41/1486Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor with correction for particular operating conditions
    • F02D41/1488Inhibiting the regulation
    • F02D41/149Replacing of the control value by an other parameter

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)

Abstract

PURPOSE:To prevent the air-fuel ratio from being enriched when the control of increment of fuel is carried out instead of the feed-back control of air-fuel ratio, by carrying out the feed-back control of air fuel ratio for every predetermined time to learn deviations in air-fuel ratio due to variations in the density of intake-air. CONSTITUTION:During operation of an engine, an electronic control circuit 8 determines whether the demand which requires the control of increment of fuel is present or not in accordance with the turn-on or turn-off of a power switch 12, and if the demand is not present, feed-back control is carried out such that the amount of fuel injection from a fuel injection valve 2 is compensated in accordance with the output of an O2 sensor 4. On the contrary, if the demand is present, the control of increment of fuel is carried out while the above-mentioned feed-back control is creased. In this stage, when the control of increment of fuel is continued for a predetermined time, it is interrupted for a predetermined time while the feed-back control of air-fuel ratio is carried out. Further, the deviation between an actual air-fuel ratio during control of fuel increment and a stoichiometric air-fuel ratio is leanred, and is used for compensating the actual air-fuel ratio during control of fuel increment which is carried out thereafter.

Description

【発明の詳細な説明】 [産業上の利用分野〕 本発明は内燃機関の空燃比制御方法に関し、特に運転上
の要求に応じて混合気の空燃比を理論空燃比より小さく
する燃料増量制御を行なうような内燃機関の空燃比制御
方法に関する。
[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an air-fuel ratio control method for an internal combustion engine, and in particular to a method for controlling the air-fuel ratio of an air-fuel mixture to a value smaller than the stoichiometric air-fuel ratio in accordance with operational requirements. The present invention relates to an air-fuel ratio control method for an internal combustion engine.

[従来技術] 従来より、内燃機関への吸入空気量に応じて燃料供給量
を制御する場合、排気管の一部に設けられた三元触媒に
よる触媒コンバータの排気浄化効率を十分なものとする
為に、排気組成、例えば排気中の酸素濃度に基づいて吸
入混合気の空燃比を推定して燃料供給量を補正し、内燃
機関の空燃比を理論空燃比とするような空燃比のフィー
ドバック制御が知られている。また、このようなフィ−
ドパツク制御をベースとして、運転上の要求、例えば登
撃や加速など、内燃機関の出力を増加させる必要のある
場合にはこのフィードバック制御をやめ、内燃機関の吸
入空気量に基づいて空燃比を理論空燃比より小さく、即
ちリッチな状態とする制御(以下、燃料増量制御と呼ぶ
)を行なう内燃機関の空燃比制御方法も知られている。
[Prior art] Conventionally, when controlling the amount of fuel supplied according to the amount of intake air to an internal combustion engine, the exhaust purification efficiency of a catalytic converter using a three-way catalyst provided in a part of the exhaust pipe has been made sufficient. Therefore, feedback control of the air-fuel ratio is used to estimate the air-fuel ratio of the intake air-fuel mixture based on the exhaust composition, for example, the oxygen concentration in the exhaust gas, correct the fuel supply amount, and adjust the air-fuel ratio of the internal combustion engine to the stoichiometric air-fuel ratio. It has been known. Also, such fee
Based on feedback control, this feedback control is stopped when it is necessary to increase the output of the internal combustion engine due to driving demands such as climbing or acceleration, and the air-fuel ratio is theoretically adjusted based on the intake air amount of the internal combustion engine. A method for controlling the air-fuel ratio of an internal combustion engine is also known, in which the air-fuel ratio is controlled to be smaller than the air-fuel ratio, that is, to be in a rich state (hereinafter referred to as fuel increase control).

[発明が解決しようとする問題点コ かかる従来技術を背景として、本発明が解決しようとす
るところは、 運転上の要求がら空燃比のフィードバック制御を中止し
、燃料増量制御が継続して行なわれる場合に、大気の温
度や大気圧が大きく変化したり、連続した登墾などによ
って燃料増量制御中に車両の高度が変化したりすると、
吸入空気の密度が変化する為に、エアフロメータのよう
なベーン式の吸入空気量センサやカルマン渦を利用した
カルマン渦式吸入空気量センサ等の吸入空気量センサを
用いている場合、吸入空気重量の測定が不正確となる結
果、実空燃比が燃料増量制御実施中の目標空燃比からズ
してしまい、正確な空燃比制御が行なえなくなることが
あるという問題である。
[Problems to be Solved by the Invention] Against the background of the prior art, the problem to be solved by the present invention is to stop feedback control of the air-fuel ratio due to operational demands and continue to perform fuel increase control. If the atmospheric temperature or atmospheric pressure changes significantly, or if the altitude of the vehicle changes during fuel increase control due to continuous climbing, etc.
Since the density of intake air changes, when using an intake air amount sensor such as a vane-type intake air amount sensor such as an air flow meter or a Karman vortex type intake air amount sensor that uses Karman vortices, the intake air weight As a result of inaccurate measurement, the actual air-fuel ratio deviates from the target air-fuel ratio during fuel increase control, and accurate air-fuel ratio control may not be possible.

第7図は車両が海抜零メートルから4000メートルま
で燃料増量制御を継続しながら、即ちスロットル開度が
大である事を示すパワースイッチがオンのままで登撃し
た場合に生じる過剰な燃料供給率を示すものである。図
において、破線■はエアフロメータのようなベーン式の
吸入空気量検出手段を用いた場合の、実線にはカルマン
渦を利用した吸入空気量検出手段を用いた場合の、各々
の燃料過剰率(換言すれば減量すべき燃料量の要求補正
量)を示しているが、これらの偏差は高度上昇に伴う大
気圧の低下、即ち空気密度の低下によって、ベーン式の
あるいはカルマン渦式の吸入空気量検出手段に生じる検
出上の偏差に起因している。
Figure 7 shows the excessive fuel supply rate that occurs when a vehicle climbs from sea level to 4,000 meters while continuing fuel increase control, that is, with the power switch, which indicates a large throttle opening, left on. This shows that. In the figure, the broken line ■ indicates the fuel excess rate ( In other words, the required correction amount for the amount of fuel to be reduced), but these deviations are due to the decrease in atmospheric pressure that accompanies the increase in altitude, that is, the decrease in air density. This is caused by a detection deviation occurring in the detection means.

従って、運転上の要求がら空燃比のフィードバック制御
を止めて、燃料増量制御を行ない、その継続中に大気の
温度が上昇したり大気圧が低下したり、あるいは登雫等
によって空気密度が小さくなったりすると、吸入空気量
検出上の偏差によって混合気の空燃比がリッチとなって
しまい、特にカルマン渦式の吸入空気量検出手段を用い
ている場合には、ベーン式と較べて空気密度の変化が直
接反映される為、混合気の空燃比が7〜9程度となって
しまうことがあるなど過剰にリッチとなり、点火プラグ
でのくすぶり等を招いたり、失火してエンジンストール
に致る場合も考えられる等の問題があった。
Therefore, due to operational requirements, feedback control of the air-fuel ratio is stopped and fuel increase control is performed.During this operation, the atmospheric temperature increases, atmospheric pressure decreases, or the air density decreases due to raindrops, etc. If a Karman vortex type intake air amount detection means is used, the air-fuel ratio of the mixture becomes rich due to a deviation in the intake air amount detection. Since this is directly reflected, the air-fuel ratio of the air-fuel mixture may become excessively rich, such as being around 7 to 9, which may lead to smoldering at the spark plug, or misfire and engine stall. There were some possible problems.

[発明の目的] 本発明は上記の点に鑑みなされたもので、その目的とす
るところは空燃比のフィードバック制御に替えて、運転
上の要求から、空燃比を理論空燃比より小さな空燃比と
するよう燃料の増量制御を継続して行なう場合に、空気
密度の変化によって実空燃比が目標空燃比からズしてし
まうという問題を解決する内燃機関の空燃比制御方法を
提供することにある。
[Object of the Invention] The present invention has been made in view of the above points, and its purpose is to control the air-fuel ratio to be smaller than the stoichiometric air-fuel ratio due to operational requirements, instead of feedback control of the air-fuel ratio. An object of the present invention is to provide an air-fuel ratio control method for an internal combustion engine that solves the problem that the actual air-fuel ratio deviates from the target air-fuel ratio due to changes in air density when fuel increase control is continuously performed to increase the amount of fuel.

[発明の構成] かかる目的を達成する為になされた本発明の要旨は、 内燃機関へ供給される燃料と吸入空気との混合気の空燃
比が、理論空燃比となるように、燃料供給量を該内燃機
関の排気組成に基づいてフィードバック制御し、 運転上の要求がある時には、前記混合気の空燃比を理論
空燃比より小さな目標空燃比とする為に前記フィードバ
ック制御を止めて燃料を増、量する燃料増量制御を行な
う内燃機関の空燃比制御方法において、 燃料増量制御が所定時間続いた時、所定の時間燃料増量
制御を中止して、前記フィードバック制御を行ない、燃
料増量制御実施中に生じた実空燃比の理論空燃比からの
偏差を学習することにより、その後に実施される燃料増
量制御中の実空燃比を前記目標空燃比に向けて補正する
ことを特徴とする内燃機関の空燃比制御方法にある。
[Structure of the Invention] The gist of the present invention, which has been made to achieve the above object, is to: adjust the amount of fuel supplied so that the air-fuel ratio of the mixture of fuel and intake air supplied to the internal combustion engine becomes the stoichiometric air-fuel ratio; is feedback-controlled based on the exhaust composition of the internal combustion engine, and when there is an operational requirement, the feedback control is stopped and fuel is increased in order to set the air-fuel ratio of the air-fuel mixture to a target air-fuel ratio smaller than the stoichiometric air-fuel ratio. In an air-fuel ratio control method for an internal combustion engine that performs fuel increase control, when the fuel increase control continues for a predetermined time, the fuel increase control is stopped for a predetermined time and the feedback control is performed, and the fuel increase control is performed while the fuel increase control is being performed. An air-fuel ratio for an internal combustion engine, characterized in that the actual air-fuel ratio during subsequent fuel increase control is corrected toward the target air-fuel ratio by learning the deviation of the actual air-fuel ratio from the stoichiometric air-fuel ratio. It is in the fuel ratio control method.

次に本発明の基本的構成を第1図のフローチャートを用
いて説明する。図示する如く、本発明の内燃機関の空燃
比制御方法は内燃機関の運転中繰返し実行され、 Pl :燃料の増量制御をすべき運転上の要求があるか
否かの判断を行なうステップ、 P2 :燃料の増量制御が実施されてから所定時間T1
が経過したか否かを判断するステップ、■ P3:時間T1の経過後、所定の時間T2が経過したか
否かを判断するステップ、 P4:空燃比のフィードバック制御茶実施し、空燃比の
補正値の学習を実行するステップ、P5 :上記フィー
ドバック制御を中止し、燃料の増量制御を実施するステ
ップ、 を次の手順で実行するものである。
Next, the basic configuration of the present invention will be explained using the flowchart shown in FIG. As shown in the figure, the method for controlling the air-fuel ratio of an internal combustion engine according to the present invention is repeatedly executed during operation of the internal combustion engine, and includes the following steps: P1: determining whether or not there is an operational demand for increasing fuel amount; P2: Predetermined time T1 after fuel increase control is implemented
P3: After the elapse of time T1, determining whether a predetermined time T2 has elapsed; P4: Performing air-fuel ratio feedback control and correcting the air-fuel ratio. The step of executing value learning, P5: step of canceling the feedback control and implementing fuel increase control, is executed in the following procedure.

即ら、内燃機関の運転中、出力増加を行なう為に燃料の
増量制御をする要求があるか否かを判断しくステップP
1)、要求がなければ空燃比のフィードバック制御を実
施し理論空燃比からの実空燃比の偏差を学習しくステッ
プP4〉、上記の要求があれば燃料の増量制御が行なわ
れ始めてから所定時間T1が経過したか否かを判断しく
ステップP2)、経過していなければ空燃比のフィード
バック制御に替えて引続き燃料の増量制御を実施しくス
テップP5)、時間T1が経過していれば時間T1の経
過後、所定の時間T2が経過したかを判断・しくステッ
プP3)、時間T2が経過していなければ燃料の増量制
御の要求があってもこれに替えて空燃比のフィードバッ
ク制御を実施し理論空燃比からの実空燃比の偏差を学習
しくステップP4)、時間T2が経過していれば再び燃
料増量制御を実施づる〈ステップP5 )よう構成され
ている。尚、ここで、所定時間T1とは、空燃比のフィ
ードバック制御を燃料の増量制御に切換えた時点からの
経過時間を意味しており、燃料を増量するような運転上
の要求があるにもかかわらず、本発明の空燃比の制御方
法に従って空燃比のフィードバック制御が行なわれたの
ちに、再び制御が燃料の増量制御に切換えられた時点を
零として、再度上記時間T1の経過が判断される。
That is, during operation of the internal combustion engine, it is determined whether or not there is a request to increase the amount of fuel in order to increase the output.
1) If there is no request, feedback control of the air-fuel ratio is performed to learn the deviation of the actual air-fuel ratio from the stoichiometric air-fuel ratio (Step P4); if the above request is made, control is performed for a predetermined time T1 after the fuel increase control starts. Step P2) to determine whether or not time has elapsed; if not, continue fuel increase control instead of air-fuel ratio feedback control to step P5); if time T1 has elapsed, time T1 has elapsed. After that, it is determined whether the predetermined time T2 has elapsed (step P3), and if the time T2 has not elapsed, even if there is a request for fuel increase control, feedback control of the air-fuel ratio is performed instead to maintain the stoichiometric air. The deviation of the actual air-fuel ratio from the fuel ratio is learned (step P4), and if time T2 has elapsed, the fuel increase control is performed again (step P5). Note that the predetermined time T1 here means the time elapsed from the time when the air-fuel ratio feedback control was switched to the fuel increase control, and even though there is an operational request to increase the fuel amount, First, after feedback control of the air-fuel ratio is performed according to the air-fuel ratio control method of the present invention, the elapse of the time T1 is determined again, with the time point at which the control is switched to fuel increase control again as zero.

又、所定時間T1の経過後に、空燃比のフィードバック
制御を実施する時間T2は、予め定まった時間とする代
わりに、空燃比制御によるフィードバック制御における
空燃比の偏差の学習が終了するまでの時間として、本発
明の内燃機関の空燃比制御方法を構成することもできる
In addition, the time T2 for performing the air-fuel ratio feedback control after the predetermined time T1 has elapsed is set as the time until learning of the air-fuel ratio deviation in the feedback control by the air-fuel ratio control is completed, instead of being set as a predetermined time. , it is also possible to configure the air-fuel ratio control method for an internal combustion engine according to the present invention.

[実施例J 以下、本発明の実施例を図面に基づいて詳細に説明する
[Example J Hereinafter, an example of the present invention will be described in detail based on the drawings.

第2図は本発明の空燃比制御方法を適用する内燃機関と
その周辺装置を含む空燃比制御装置の一例を示す概略構
成図であって、1は内燃機関本体、2は電磁式の燃料噴
射弁、4は内燃機関1からの排気中の残存酸素8度に応
じて電気信号を発する酸素濃度センサ、6は内燃機関の
空燃比制御を行なう電子制御回路を各々表わしている。
FIG. 2 is a schematic configuration diagram showing an example of an air-fuel ratio control device including an internal combustion engine and its peripheral devices to which the air-fuel ratio control method of the present invention is applied, in which 1 is the internal combustion engine main body, 2 is an electromagnetic fuel injection A valve 4 represents an oxygen concentration sensor that generates an electric signal in response to 8 degrees of residual oxygen in the exhaust gas from the internal combustion engine 1, and 6 represents an electronic control circuit that controls the air-fuel ratio of the internal combustion engine.

又、内燃機関1の種々の運転状態を検出する為に、図示
する如く、吸気温センサ8.スロットルバルブ10の開
度と共にパワースイッチによりスロットル開度が所定値
以上であることを検出するスロットルセンサ12.内燃
機関本体1のエアクリ−〇す15とサージタンク16と
の間に設置されカルマン渦を利用して吸入空気量を検出
するカルマン渦式の吸入空気量センサ18.内燃機関1
の冷却水水温を検出する水温センサ20.ディストリビ
ュータ22内部のロータ22aに対向して設置されて図
示しないクランクの一回転に24個のパルスを発生して
内燃機関1の回転数を検出する回転数センサ24.同じ
くクランクの一回転に1個のパルスを発生する気筒判別
センサ25等のセンサ群が備えられている。
Further, in order to detect various operating conditions of the internal combustion engine 1, an intake air temperature sensor 8. Throttle sensor 12 which detects whether the opening of the throttle valve 10 and the throttle opening is a predetermined value or more using a power switch. A Karman vortex type intake air amount sensor 18 is installed between the air cleaner 15 of the internal combustion engine main body 1 and the surge tank 16, and detects the intake air amount using Karman vortices. internal combustion engine 1
A water temperature sensor 20 for detecting the temperature of the cooling water. A rotation speed sensor 24 is installed facing the rotor 22a inside the distributor 22 and detects the rotation speed of the internal combustion engine 1 by generating 24 pulses per revolution of a crank (not shown). Similarly, a group of sensors such as a cylinder discrimination sensor 25 which generates one pulse per revolution of the crank are provided.

ディストリビュータ22にはイグナイタ26に発生する
高電圧パルスが供給されており、ディストリビュータ2
2は各気筒の燃焼サイクルに同期して、内燃機関1のシ
リンダ28の上部に螺嵌された点火プラグ30へ、この
高電圧を印加し混合気への点火を行なっている。又、3
2は内燃機関1の排気管34に設けられた触媒コンバー
タである。
The high voltage pulse generated by the igniter 26 is supplied to the distributor 22.
2 applies this high voltage to a spark plug 30 screwed into the upper part of the cylinder 28 of the internal combustion engine 1 in synchronization with the combustion cycle of each cylinder to ignite the air-fuel mixture. Also, 3
2 is a catalytic converter provided in the exhaust pipe 34 of the internal combustion engine 1.

次に、電子制御回路6の内部構成と電気信号の系統につ
いて説明する。電子制御回路6は、予め定められたプロ
グラムに従ってデータの入力や演算及び制御を行なう中
央処理ユニット(CPLI)6o、制御プログラム等を
予め記憶しておく読み出し専用のメモリ<ROM>62
、データ等を自由に書き込み・読み出し可能な一時記憶
メモリ(RAMン64、内燃機関1の運転状態を検出す
る種々のセンサ群により信号を入力する入力ポートロ5
、イグナイタ26や燃料噴射弁2等へ制御信号を出力す
る出力ポードロア、CPU60.R○M62等上記各素
子を相互に接続するデータバス68、キースイッチ71
を介してバッテリ73に接続されて電子制御回路6全体
に安定化された電圧を供給する電源回路75、等を備え
ている。
Next, the internal configuration of the electronic control circuit 6 and the electrical signal system will be explained. The electronic control circuit 6 includes a central processing unit (CPLI) 6o that inputs data, performs calculations, and performs control according to a predetermined program, and a read-only memory <ROM> 62 that stores control programs, etc. in advance.
, a temporary storage memory (RAM 64) in which data, etc. can be freely written and read;
, an output port lower that outputs control signals to the igniter 26, the fuel injection valve 2, etc., and the CPU 60. A data bus 68 and a key switch 71 that interconnect the above-mentioned elements such as R○M62.
The power supply circuit 75 is connected to a battery 73 via a power supply circuit 75 and supplies a stabilized voltage to the entire electronic control circuit 6.

入力ポートロ5は、カルマン渦式の吸入空気量センサ1
8と回転数センサ24と気筒判別センサ25からのパル
ス信号を入力するパルス入力部65aと、吸気温センサ
8.スロットルセンサ12゜II?素濃度センサ4.水
温センサ20からの各検出値に応じたアナログ信号を入
力するアナログ入力部65bとを有している。一方、内
燃機関1の図示しないクランク角度を回転数センサ24
がらの信号によって検出し、これに同期してイグナイタ
26を駆動する信号と、燃料噴射量に応じて定まる燃料
噴射時間だけ燃料噴射弁2を開弁する制御信号とが出力
ポードロアを介して出力されている。
The input port 5 is a Karman vortex type intake air amount sensor 1
8, a pulse input section 65a that inputs pulse signals from the rotation speed sensor 24 and the cylinder discrimination sensor 25, and an intake temperature sensor 8. Throttle sensor 12° II? Elementary concentration sensor 4. It has an analog input section 65b into which an analog signal corresponding to each detection value from the water temperature sensor 20 is input. On the other hand, the crank angle (not shown) of the internal combustion engine 1 is detected by the rotation speed sensor 24.
A signal for driving the igniter 26 and a control signal for opening the fuel injection valve 2 for a fuel injection time determined according to the fuel injection amount are outputted via the output port lower. ing.

該制御信号によって燃料噴射弁2は制御・開弁され、図
示しない燃料圧送ポンプより燃料供給をうけて、吸気管
14内部への燃料噴射が行なわれるよう構成されている
The fuel injection valve 2 is controlled and opened by the control signal, and fuel is injected into the intake pipe 14 by receiving fuel from a fuel pump (not shown).

次に電子制御回路6内で行なわれる本発明の内燃機関の
空燃比制御方法の一例としての制御ルーチンを、第3図
のフローチャートに拠って説明する。尚、第3図のフロ
ーチャートは諸条件に従って、空燃比のフィードバック
制御を行なうか、あるいはこれに替えて燃料増量制御を
行なうかを指示するものであって、実際の空燃比のフィ
ードバック制御や燃料増量制御は本制御ルーチンと共に
繰返し実行される図示しない他の制御ルーチンにより実
行される。これらの制御は周知のものなので特に説明し
ないが、空燃比のフィードバック制御において実行され
る学習値制御については第4図のフローチャートに依拠
して説明する。
Next, a control routine as an example of the air-fuel ratio control method for an internal combustion engine according to the present invention, which is carried out in the electronic control circuit 6, will be explained with reference to the flowchart shown in FIG. The flowchart in Figure 3 is for instructing whether to perform air-fuel ratio feedback control or alternatively, fuel increase control, according to various conditions. Control is executed by another control routine (not shown) that is repeatedly executed together with this control routine. Since these controls are well known, they will not be specifically explained, but the learned value control executed in the feedback control of the air-fuel ratio will be explained based on the flowchart of FIG.

第3図において、本制御ルーチンは所定の内燃機関の運
転中、所定の時間(例えば4m5ec)毎に起動されて
、 100:パワースイッチがオン(ON>となっているか
否かを判断するステップ、 110:カウンタCを1だけインクリメントする処理を
行なうステップ、 120:カウンタCの値が所定の時間T1に対応した値
CT1以上であるか否かを判断するステップ、 130:カウンタCの値がその後の所定の時間T2に対
応したもうひとつの値CT2以上であるか否かを判断す
るステップ、 140:カウンタCの値を零に戻す処理を行なうステッ
プ、 150:カウンタCの値を零にセットJる処理を行なう
ステップ、 160:空燃比フィードバック制御を中止しこれに替え
て燃料増量制御の実施を指示する処理を行なうステップ
、 170:燃料増量制御を解除し、フィードバック制御の
実施を指示する処理を行なうステップ、を、以下の手順
で実行する。
In FIG. 3, this control routine is started at predetermined time intervals (for example, 4 m5 ec) during operation of a predetermined internal combustion engine, and includes the following steps: 100: determining whether the power switch is on (ON>); 110: A step of incrementing the counter C by 1; 120: A step of determining whether the value of the counter C is greater than or equal to the value CT1 corresponding to a predetermined time T1; 130: The value of the counter C is incremented by 1 after that. A step of determining whether the value is greater than or equal to another value CT2 corresponding to a predetermined time T2, 140: A step of performing a process of returning the value of the counter C to zero, 150: Setting the value of the counter C to zero. 160: Performing a process of canceling the air-fuel ratio feedback control and instructing the implementation of fuel increase control instead; 170: Performing a process of canceling the fuel increase control and instructing the implementation of feedback control. Execute step as follows.

まずステップ100でスロットルセンサ12内の図示し
ないパワースイッチがオン(rONJ )、即ちスロッ
トル10が所定の開度以上(はぼ全開)となっているか
否かの判断が行なわれる。パワースイッチがオンとなっ
ていなければ、特に燃料増量制御をすべき運転上の要求
はないとして、処理はステップ15oへ進み、プログラ
ム上のカウンタの値Cを零にセットし、ステップ170
へ進んで、燃料増量制御の解除と空燃比フィードバック
制御実施の指令を、例えばフラッグの値をセットするな
どして出力する処理を行なう。一方、ステップ100の
判断において、加速や登撃など運転上の要求から図示し
ないアクセルが踏み込まれパワースイッチがrONJと
なっていると、通常は常に混合気の空燃比を理論空−燃
比より小さい、所謂リッチな状態とすべく、空燃比のフ
ィードバック制御に替えて燃料増量制御が行なわれてい
る訳であるが、本制御ルーチンでは所定の条件下で空燃
比のフィードバック制御も行なわれる為に、これを判断
すべく処理はステップ110へ進み、ステップ110以
下の判断・処理が行なわれる。ステップ100での判断
がrYEsJ  (パワースイッチはオン)の場合、処
理はステップ110へ進み、内燃機関1の始動時には初
期化されて零にセットされるプログラム上のカウンタ値
Cを1だけインクリメントする処理を行ない、続くステ
ップ120で、このカウンタの値Cが予め定められた値
CT1以上であるか否かの判断が行なわれる。
First, in step 100, it is determined whether a power switch (not shown) in the throttle sensor 12 is turned on (rONJ), that is, whether or not the throttle 10 is opened to a predetermined opening degree or more (almost fully open). If the power switch is not turned on, it is assumed that there is no operational requirement for fuel increase control, and the process proceeds to step 15o, where the counter value C on the program is set to zero, and step 170.
Then, a process is performed to output a command to cancel fuel increase control and implement air-fuel ratio feedback control, for example by setting a flag value. On the other hand, in the judgment at step 100, if the accelerator (not shown) is depressed due to driving demands such as acceleration or attack, and the power switch is set to rONJ, the air-fuel ratio of the mixture is normally always lower than the stoichiometric air-fuel ratio. In order to achieve a so-called rich state, fuel increase control is performed instead of air-fuel ratio feedback control, but this control routine also performs air-fuel ratio feedback control under predetermined conditions. The process proceeds to step 110 in order to determine this, and the determinations and processes from step 110 onwards are performed. If the determination in step 100 is rYEsJ (the power switch is on), the process proceeds to step 110, where the counter value C on the program, which is initialized and set to zero when the internal combustion engine 1 is started, is incremented by 1. In the following step 120, it is determined whether the value C of this counter is greater than or equal to a predetermined value CT1.

ここで仮にCTIが50000.後で述べるCT2が6
0000であれば、燃料増量制御を開始してからC≧5
0oOOまで、即チ50000 X 、4m5ec後ま
ではステップ120での判断はrNOJとなり、処理は
ステップ160へ移行する。一方、ステップ120での
判断がrYEsJの時(C≧CT1が成立している時〉
には、処理はステップ130へ進み、カウンタの値Cが
012以上であるか否かの判断を行なう。ステップ13
0での判断がrNOJである時には、燃料増量制御が開
始されてから時間T1 (50000x4n+5ec)
の経過後であり時間T2  (60000x4msec
)の経過前であることになり、処理は前述のステップ1
70へ移行する。ステップ130での判断が「YES」
、即ち燃料増量制御の開始から時間T2(60000X
 4 m5ec) (7)経過後テアレバ、処理はステ
ップ140へ進み、カウンタの値Cを零に戻してから、
処理はステップ160へ移行する。
Here, suppose CTI is 50000. CT2, which will be described later, is 6
If it is 0000, C≧5 after starting fuel increase control.
Until 0oOO, that is, after 50000 X and 4m5ec, the determination at step 120 is rNOJ, and the process moves to step 160. On the other hand, when the determination at step 120 is rYEsJ (when C≧CT1 holds)
If so, the process proceeds to step 130, where it is determined whether the counter value C is 012 or more. Step 13
When the judgment at 0 is rNOJ, time T1 (50000x4n+5ec) after fuel increase control is started.
After the elapse of time T2 (60000x4msec
) has not yet passed, and the process is the same as step 1 described above.
Move to 70. The determination at step 130 is "YES"
, that is, time T2 (60000X
4 m5ec) (7) After the tear lever has elapsed, the process proceeds to step 140, returns the counter value C to zero, and then
Processing moves to step 160.

ステップ160では、運転上の要求から燃料増量制御が
必要であり、なおかつカウンタの値Cから燃料増量制御
を行なってもよい時間内であるとして、空燃比のフィー
ドバック制御を中止し燃料増量制御を実施するような指
令を、例えばフラッグの値をリセットするなどして出力
する処理を行なう。上記ステップ160又はステップ1
70の終了後、本制御ルーチンは終了する。
In step 160, the air-fuel ratio feedback control is stopped and the fuel increase control is performed because the fuel increase control is necessary due to operational demands and the time is within which the fuel increase control can be performed based on the value C of the counter. It performs processing to output commands such as, for example, resetting flag values. Step 160 or Step 1 above
After the completion of step 70, this control routine ends.

次に、図示しない空燃比制御ルーチンにおいて、空燃比
のフィードバック制御が行なわれる場合の学習値制御に
ついて説明する。第4図は空燃比のフィードバック制御
ルーチン内で行なわれる学習値の制御ルーチンを示すフ
ローチャートであって、酸素siセンサ4の出力電圧が
ハイレベルとロウレベルの間で反転する毎に割込ルーチ
ンとして起動される。
Next, learned value control when air-fuel ratio feedback control is performed in an air-fuel ratio control routine (not shown) will be described. FIG. 4 is a flowchart showing a learning value control routine performed in the air-fuel ratio feedback control routine, which is activated as an interrupt routine every time the output voltage of the oxygen Si sensor 4 is reversed between high level and low level. be done.

まずステップ200では酸素濃度センサ4の出力を比例
積分して得られる空燃比フィードバック補正係数FAF
のピーク値の相加平均値FAFAVを求める処理が行な
われる。即ち、本ルーチンは酸素S度センサ4の出力が
反転する毎に起動されることから、その直後の空燃比フ
ィードバック補正係数費FAFの値と前回のピーク値F
AFoldとの相加平均値FAFAV= (FAF+F
AFo1d)/2を求める処理が行なわれる。続くステ
ップ210では次回の処理に備えて、現在の空燃比のフ
ィードバック補正係数FAFを前回のピーク値FAFo
ldとしてRAM64の所定のエリアに格納する処理が
行なわれる。次のステップ220ではプログラム上のカ
ウンタの値Crを11だけインクリメントする処理が行
なわれ、続くステップ230ではOr≧5であるか否か
の判断が行なわれる。Or≧5でなければ、以下の処理
は何も行なわれず、本制御ルーチンは終了する。従って
、酸素濃度センサ4の出力が5回反転する毎にステップ
230での判断はrYEsJとなって学習値KGの更新
又は維持が行なわれる。即ち、ステップ230に続くス
テップ240では、空燃比フィードバック補正係数FA
Fの平均値FAFA■が、空燃比制御が平衡に達してい
る時の値、0゜98〜1.02の範囲に対してどのよう
な大小関係にあるかの判断が行なわれる。この平均値F
AF△■が0.98未満の時には処理はステップ250
へ進み、空燃比制御の学習値KGをβだけ(例えば3%
だけ)減算する処理が、平均値FAFAV>1.02で
あれば処理はステップ260へ進み、前記学習値KGを
βだけ加算する処理が、各々実行される。上述のステッ
プ250あるいはステップ260の処理の終了後、もし
くはステップ240での判断がrYESJ 、即ち前述
の平均値FAFAVが0.98以上1.02以下であつ
て学習値の更新が行なわれない場合には、処理はステッ
プ270へ進み、ステップ220でインクリメントして
きたカウンタの値Crを零に戻す処理が行なわれ、本制
御ルーチンを終了する。
First, in step 200, the air-fuel ratio feedback correction coefficient FAF is obtained by proportionally integrating the output of the oxygen concentration sensor 4.
A process is performed to obtain the arithmetic average value FAFAV of the peak values. That is, since this routine is started every time the output of the oxygen S degree sensor 4 is reversed, the value of the air-fuel ratio feedback correction coefficient cost FAF immediately after that and the previous peak value F
Arithmetic average value FAFAV= (FAF+F
Processing to obtain AFo1d)/2 is performed. In the following step 210, in preparation for the next process, the feedback correction coefficient FAF of the current air-fuel ratio is set to the previous peak value FAFo.
Processing is performed to store the data in a predetermined area of the RAM 64 as ld. In the next step 220, the counter value Cr on the program is incremented by 11, and in the following step 230, it is determined whether Or≧5. Unless Or≧5, the following processing is not performed and the present control routine ends. Therefore, every time the output of the oxygen concentration sensor 4 is reversed five times, the determination at step 230 is rYEsJ, and the learned value KG is updated or maintained. That is, in step 240 following step 230, the air-fuel ratio feedback correction coefficient FA
A determination is made as to what magnitude relationship the average value FAFA■ of F has with respect to the range of 0.98 to 1.02, which is the value when the air-fuel ratio control has reached equilibrium. This average value F
When AF△■ is less than 0.98, the process goes to step 250.
Proceed to , and change the learning value KG of air-fuel ratio control by β (for example, 3%).
If the average value FAFAV>1.02, the process proceeds to step 260, and the process of adding β to the learned value KG is executed. After the process of step 250 or step 260 described above is completed, or if the determination in step 240 is rYESJ, that is, the average value FAFAV described above is 0.98 or more and 1.02 or less and the learning value is not updated. Then, the process proceeds to step 270, where the counter value Cr incremented in step 220 is returned to zero, and this control routine ends.

上述の学習値制御ルーチンが繰返し実行される結果、理
論空燃比からの実空燃比の偏差は、最初空燃比のフィー
ドバック補正係数FAFに反映され、次第にその学習値
KGに移してかえられてゆく。図示しない燃料噴射量制
御ルーチンにおいて燃料噴射量(実際には燃料噴射時間
)τは、内燃機関1の吸入空気量と回転数とか定まる基
本燃料噴射1itTpに補正を加え、次の式(1)によ
り算出されている。
As a result of the above-described learned value control routine being repeatedly executed, the deviation of the actual air-fuel ratio from the stoichiometric air-fuel ratio is first reflected in the air-fuel ratio feedback correction coefficient FAF, and is gradually transferred to the learned value KG. In the fuel injection amount control routine (not shown), the fuel injection amount (actually fuel injection time) τ is determined by correcting the basic fuel injection 1itTp, which is determined by the intake air amount and rotational speed of the internal combustion engine 1, using the following equation (1). It has been calculated.

T−KI XTI)XFAFXKG xf  (tl、 t2.−tm) 十Tv −−−−
−−(1)尚、ここでに1は定数を、f (口、 t2
・・・tm)は内燃機関1の冷却水温等に基づいて行な
われる暖機補正等に係る他の補正係数を、TVは燃料噴
射弁の応答時間に対応する無効噴射時間を各々意味して
いる。従って、第5図に示すように、例えば登空により
燃料増量制御が継続して行なわれると、内燃機関1の空
燃比は次のように制御される。
T-KI XTI)XFAFXKG xf (tl, t2.-tm) 10Tv -----
--(1) Here, 1 is a constant, f (mouth, t2
...tm) means other correction coefficients related to warm-up correction etc. performed based on the cooling water temperature of the internal combustion engine 1, etc., and TV means the invalid injection time corresponding to the response time of the fuel injection valve. . Therefore, as shown in FIG. 5, when fuel increase control is continuously performed due to, for example, climbing into the sky, the air-fuel ratio of the internal combustion engine 1 is controlled as follows.

まず運転上の要求(この場合は登欝による出力増の要求
)によってスロットルセンサ12内のパワースイッチが
オンとなれば、第3図のフローチャートから明らかなよ
うに、最初、空燃比のフィードバック制御に替えて燃料
増量制御を実施するような指令がなされるので、図示し
ない空燃比制御ルーチンでは酸素濃度センサ4の出力電
圧(空燃比がリッチの時ハイレベル、リーンの時ロウレ
ベル)によって燃料噴射量を増量又は減量し、空燃比を
理論空燃比とするように制御していたフィードバック制
御を中止し、これに替えて内燃機関の吸入空気量と回転
数とから求まる基本燃料噴射を各種補正項で補正した燃
料噴射量を、更に、例えば20%増量するような燃料増
量制御が行なわれる。しかし、パワースイッチがオンと
なったままで燃料増量制御が時間T1以上継続した場合
には、吸入空気量センサ18による吸入空気量の測定に
ズレが生じている可能性があるとして、一旦燃料増量制
御を中止して、所定の時間T2まで空燃比のフィードバ
ック制御が行なわれる。本実施例では、この空燃比のフ
ィードバック制御の実施中に、第4図のフローチャート
をもちいて説明した学習ルーチンにおける空燃比の偏差
の学習が行なわれる。従って燃料増量制御の実施中に、
吸入空気の密度の変化に起因する空燃比の偏差が生じて
も、所定の開綿をおいて、実行される空燃比のフィード
バック制御において、この偏差は空燃比フィードバック
補正係数FAFより学習値KGへと学習され解消される
ので、燃料増量制御中の空燃比の偏差は抑制されること
になる。この結果、大気圧の急激な低下や吸入空気温の
上昇あるいは継続する登平等によって吸入空気量の密度
が変化し、燃焼に関与する吸入空気量が測定値より減少
しており混合気の空燃比が過剰にリッチとなって、点火
プラグでのくずぶりや失火してエンジンストールに至る
ことがあるという問題は充分に解決された。
First, when the power switch in the throttle sensor 12 is turned on due to a driving request (in this case, a request for increased output due to climbing), as is clear from the flowchart in FIG. 3, the air-fuel ratio feedback control is first performed. Therefore, in the air-fuel ratio control routine (not shown), the fuel injection amount is controlled based on the output voltage of the oxygen concentration sensor 4 (high level when the air-fuel ratio is rich, low level when the air-fuel ratio is lean). Feedback control that controlled the air-fuel ratio to be the stoichiometric air-fuel ratio by increasing or decreasing the amount is discontinued, and instead, the basic fuel injection determined from the intake air amount and rotational speed of the internal combustion engine is corrected using various correction terms. Fuel increase control is performed to further increase the fuel injection amount, for example, by 20%. However, if the power switch remains on and the fuel increase control continues for more than time T1, it is assumed that there is a possibility that there is a discrepancy in the measurement of the intake air amount by the intake air amount sensor 18, and the fuel increase control is temporarily stopped. is stopped, and feedback control of the air-fuel ratio is performed until a predetermined time T2. In this embodiment, during the execution of the air-fuel ratio feedback control, the air-fuel ratio deviation is learned in the learning routine described using the flowchart of FIG. 4. Therefore, during fuel increase control,
Even if a deviation in the air-fuel ratio occurs due to a change in the density of intake air, in the air-fuel ratio feedback control that is executed after a predetermined gap, this deviation is calculated from the air-fuel ratio feedback correction coefficient FAF to the learned value KG. Since this is learned and canceled, the deviation in air-fuel ratio during fuel increase control is suppressed. As a result, the density of the intake air amount changes due to a sudden drop in atmospheric pressure, a rise in the intake air temperature, or a continuous increase in air temperature, and the amount of intake air involved in combustion is lower than the measured value, causing the air-fuel ratio of the mixture to change. The problem of the engine becoming excessively rich, which could cause the spark plug to swell or misfire, leading to an engine stall, has been satisfactorily solved.

又、本実施例では燃料増量制御実施中に生じた空気密度
の変化による実空燃比の偏差は、内燃機関の空燃比制御
のひとつとして基本的に行なわれる空燃比フィードバッ
ク制御を用いて、その学習値制御により補正されている
。従って車両の高度や大気圧等を測定して空燃比を補正
するのではなく、空燃比制御方法が複雑なものになるこ
ともない。
In addition, in this embodiment, deviations in the actual air-fuel ratio due to changes in air density that occur during fuel increase control are learned using air-fuel ratio feedback control, which is basically performed as one of the air-fuel ratio controls for internal combustion engines. Corrected by value control. Therefore, instead of correcting the air-fuel ratio by measuring the altitude of the vehicle, atmospheric pressure, etc., the air-fuel ratio control method does not become complicated.

次に本発明の第2実施例について説明する。第2実施例
の内燃機関の空燃比制御方法は、第6図に示すフローチ
ャートに従って行なわれる制御を主要部として構成され
ている。本実施例においても、実際の燃料噴射量の算出
や燃料噴射弁2等の制御は図示しない周知の制御ルーチ
ンで行なわれており、燃料噴射量制御ルーチン内の空燃
比の学習値制御は第1実施例で説明した第4図のフロー
チャートに従って実行されている。第2実施例における
第6図のフローチャートに示したステップ300ないし
ステップ370は、ステップ325を除いて、第1実施
例の第3図に示したフローチャートのステップ100な
いしステップ170に、各々対応しているので説明は省
略する。
Next, a second embodiment of the present invention will be described. The air-fuel ratio control method for an internal combustion engine according to the second embodiment is mainly configured with control performed according to the flowchart shown in FIG. In this embodiment as well, calculation of the actual fuel injection amount and control of the fuel injection valve 2, etc. are performed by a well-known control routine (not shown), and the learned value control of the air-fuel ratio in the fuel injection amount control routine is performed by the first control routine. The process is executed according to the flowchart in FIG. 4 described in the embodiment. Steps 300 to 370 shown in the flowchart of FIG. 6 in the second embodiment correspond to steps 100 to 170 in the flowchart shown in FIG. 3 of the first embodiment, respectively, except for step 325. Therefore, the explanation will be omitted.

第2実施例ではステップ320とステップ330の間に
新たなステップ325が挿入されており、このステップ
では空燃、比フィードバック補正係数の平均値FAFA
Vが、空燃比フィードバック制御継続中の値1の近傍(
±α以内)にあるか否かの判断が行なわれる。上記の平
均値FAFAVが値1に対して±α(例えば±0.02
)以内にない場合には、ステップ235の判断はrYE
SJとなって処理はステップ340へ進む。この場合は
第1実施例と全く同一の制御となる。しかしながら、ス
テップ235でめ判断がrNOJ 、即ち空燃比のフィ
ードバック補正係数FAFの平均値FAFAVが値1に
対して±α以内にはいっていれば、処理はステップ33
0をとばしてステップ340へ移行する。この場合には
、燃料増量制御を実施する要求がありながら実空燃比の
ズレを補正する為に所定の間隔で行なわれる空燃比のフ
ィードバック制御の実施時において−、理論空燃比から
の実空燃比の偏差を学習し終われば、予め設定された時
間T2の経過前であっても空燃比のフィードバック制御
を解除し燃料増量制御に復するように働く。従って、第
1の実施例の効果に加えて、出力増量の要求と空燃比の
適正な制御とを効率よく両立させることができるという
効果が存在する。
In the second embodiment, a new step 325 is inserted between steps 320 and 330, and in this step, the average value FAFA of the air-fuel and ratio feedback correction coefficients is
V is near the value 1 during air-fuel ratio feedback control (
(within ±α). The above average value FAFAV is ±α (for example ±0.02
), the judgment in step 235 is rYE.
The process becomes SJ and the process proceeds to step 340. In this case, the control is exactly the same as in the first embodiment. However, if the final judgment in step 235 is that rNOJ, that is, the average value FAFAV of the air-fuel ratio feedback correction coefficient FAF is within ±α with respect to the value 1, the process proceeds to step 33.
0 is skipped and the process moves to step 340. In this case, when performing air-fuel ratio feedback control that is performed at predetermined intervals to correct deviations in the actual air-fuel ratio while there is a request to implement fuel increase control, the actual air-fuel ratio from the stoichiometric air-fuel ratio Once the deviation has been learned, the air-fuel ratio feedback control is canceled and the fuel increase control is resumed even before the preset time T2 has elapsed. Therefore, in addition to the effects of the first embodiment, there is the effect that the request for increased output and appropriate control of the air-fuel ratio can be efficiently balanced.

尚、これらの実施例では、吸入空気量の検出にカルマン
渦式吸入空気量センサを用いたが、エアフロメータ等の
ベーン式吸入空気量センサにも、全く同様に適用するこ
とができる。又、上述の実施例では運転上の要求をスロ
ットルセンサ12のパワースイッチの状態で知るように
構成したが、アクセルセンサ等を用いて検出するように
構成することも何ら差支えない。
In these embodiments, a Karman vortex type intake air amount sensor is used to detect the amount of intake air, but the present invention can be similarly applied to a vane type intake air amount sensor such as an air flow meter. Further, in the above-described embodiment, the driving request is determined by the state of the power switch of the throttle sensor 12, but it may be configured to be detected using an accelerator sensor or the like.

以上本発明のい(つかの実施例について説明したが、本
発明はこのような実施例に何等限定されるものではなく
、本発明の要旨を逸脱しない範囲において、種々なる態
様で実施し得ることは勿論である。
Although some embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way, and can be implemented in various forms without departing from the gist of the present invention. Of course.

[発明の効果] 以上詳述したように、本発明の内燃機関の空燃比制御方
法は、運転上の要求がら空燃比のフィードバック制御に
替えて空燃比を理論空燃比より小さな目標空燃比とする
燃料増量制御が行なわれる場合に、この燃料増量制御が
所定時間続いた時、所定の時間燃料増量制御を中止して
空燃比のフィードバック制御を行ない、燃料増量制御の
実施中に生じた空燃比の偏差を学習して、燃料増量制御
実施中の実空燃比を上記目標空燃比に向けて補正するよ
う構成されている。
[Effects of the Invention] As detailed above, the air-fuel ratio control method for an internal combustion engine of the present invention changes the air-fuel ratio to a target air-fuel ratio smaller than the stoichiometric air-fuel ratio instead of feedback control of the air-fuel ratio in response to operational requirements. When fuel increase control is performed and this fuel increase control continues for a predetermined time, the fuel increase control is stopped for a predetermined time and air-fuel ratio feedback control is performed to adjust the air-fuel ratio that occurred during the fuel increase control. The system is configured to learn the deviation and correct the actual air-fuel ratio during execution of the fuel increase control toward the target air-fuel ratio.

従って、運転上の要求から燃料増量制御が継続して行な
われる場合でも、所定時間毎に空燃比のフィードバック
制御を行ない、吸入空気の密度の変化に起因する空燃比
の偏差を学習するので、特別な高度測定などを行なわな
くとも、燃料増量制御の継続した実施中にも空燃比を適
正に維持することができるという優れた効果を奏する。
Therefore, even if fuel increase control is continuously performed due to operational demands, feedback control of the air-fuel ratio is performed at predetermined intervals to learn air-fuel ratio deviations caused by changes in intake air density. This provides an excellent effect in that the air-fuel ratio can be maintained at an appropriate level even during continuous execution of fuel increase control without performing detailed altitude measurements.

この結果、連続した0槃のように燃料増量制御を続けな
がら吸入空気の密度が低下してゆくような場合に生じる
吸入空気量の測定上のズレに起因ターる空燃比の偏差の
問題、即ち空燃比が過剰にリッチとなつで点火プラグで
のくすぶりやエンジンストールを生じることがあるとい
う問題は充分に解消された。この効果は、空気密度の変
化が吸入空気量の測定上の制度に直接反映されるカルマ
ン渦式の吸入空気量センサを用いている場合には特に顕
著である。
As a result, the problem of deviation in the air-fuel ratio due to the deviation in the measurement of the amount of intake air that occurs when the density of the intake air decreases while the fuel increase control is continued like a continuous zero, that is, The problem of an excessively rich air-fuel ratio that could cause spark plug smoldering or engine stalling has been fully resolved. This effect is particularly noticeable when using a Karman vortex type intake air amount sensor in which changes in air density are directly reflected in the accuracy of the measurement of the intake air amount.

【図面の簡単な説明】[Brief explanation of the drawing]

第1図は本発明の基本的構成を示すフローチャート、第
2図は本発明の内燃機関の空燃比制御方法が適用される
内燃機関とその周辺装置の一例を示す概略構成図、第3
図は本発明の第1実施例を示すフローチャート、第4図
は空燃比制御ルーチンの一部として実行される学習値制
御の一例を示すフローチャート、第5図は空燃比制御の
一例を示す説明図、第6図は本発明の第2実施例を示す
フローチャート、第7図は吸入空気量測定のズレによっ
て生じる燃料の過剰の様子を示すグラフ、である。 1・・・内燃機関   2・・・燃料噴射弁4・・・酸
素濃度センサ 6・・・電子制御回路 10・・・スロットルバルブ 18・・・吸入空気量センサ 60・・・CPU
FIG. 1 is a flowchart showing the basic configuration of the present invention, FIG. 2 is a schematic configuration diagram showing an example of an internal combustion engine and its peripheral devices to which the air-fuel ratio control method for an internal combustion engine of the present invention is applied, and FIG.
Figure 4 is a flowchart showing the first embodiment of the present invention, Figure 4 is a flowchart showing an example of learned value control executed as part of the air-fuel ratio control routine, and Figure 5 is an explanatory diagram showing an example of air-fuel ratio control. , FIG. 6 is a flowchart showing a second embodiment of the present invention, and FIG. 7 is a graph showing a state of excess fuel caused by a deviation in intake air amount measurement. 1... Internal combustion engine 2... Fuel injection valve 4... Oxygen concentration sensor 6... Electronic control circuit 10... Throttle valve 18... Intake air amount sensor 60... CPU

Claims (1)

【特許請求の範囲】 1 内燃機関へ供給される燃料と吸入空気との混合気の
空燃比が、理論空燃比となるように、燃料供給量を該内
燃機関の排気組成に基づいてフィードバック制御し、 運転上の要求がある時には、前記混合気の空燃比を理論
空燃比より小さな目標空燃比とする為に前記フィードバ
ック制御を止めて燃料を増量する燃料増量制御を行なう
内燃機関の空燃比制御方法において、 燃料増量制御が所定時間続いた時、所定の時間燃料増量
制御を中止して、前記フィードバック制御を行ない、燃
料増量制御実施中に生じた実空燃比の理論空燃比からの
偏差を学習することにより、その後に実施される燃料増
量制御中の実空燃比を前記目標空燃比に向けて補正する
ことを特徴とする内燃機関の空燃比制御方法。 2 燃料増量制御を中止して行なわれるフィードバック
制御が、燃料増量制御実施中に生じた空燃比の偏差を学
習しおわるまでの時間行なわれる特許請求の範囲第1項
記載の内燃機関の空燃比制御方法。
[Claims] 1. The fuel supply amount is feedback-controlled based on the exhaust composition of the internal combustion engine so that the air-fuel ratio of the mixture of fuel and intake air supplied to the internal combustion engine becomes the stoichiometric air-fuel ratio. , an air-fuel ratio control method for an internal combustion engine, which performs fuel increase control in which the feedback control is stopped and fuel is increased when there is an operational requirement, in order to set the air-fuel ratio of the air-fuel mixture to a target air-fuel ratio that is smaller than the stoichiometric air-fuel ratio. When the fuel increase control continues for a predetermined time, the fuel increase control is stopped for a predetermined time and the feedback control is performed to learn the deviation of the actual air-fuel ratio from the stoichiometric air-fuel ratio that occurred during the execution of the fuel increase control. An air-fuel ratio control method for an internal combustion engine, comprising: correcting the actual air-fuel ratio during fuel increase control to be performed thereafter toward the target air-fuel ratio. 2. The air-fuel ratio control of an internal combustion engine according to claim 1, wherein the feedback control performed after stopping the fuel increase control is performed for a period of time until the feedback control finishes learning the air-fuel ratio deviation that occurred during the execution of the fuel increase control. Method.
JP12956884A 1984-06-22 1984-06-22 Method of controlling air-fuel ratio of internal combustion engine Pending JPS618438A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12956884A JPS618438A (en) 1984-06-22 1984-06-22 Method of controlling air-fuel ratio of internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12956884A JPS618438A (en) 1984-06-22 1984-06-22 Method of controlling air-fuel ratio of internal combustion engine

Publications (1)

Publication Number Publication Date
JPS618438A true JPS618438A (en) 1986-01-16

Family

ID=15012691

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12956884A Pending JPS618438A (en) 1984-06-22 1984-06-22 Method of controlling air-fuel ratio of internal combustion engine

Country Status (1)

Country Link
JP (1) JPS618438A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01294930A (en) * 1988-05-20 1989-11-28 Fuji Heavy Ind Ltd Air-fuel ratio control device for internal combustion engine

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01294930A (en) * 1988-05-20 1989-11-28 Fuji Heavy Ind Ltd Air-fuel ratio control device for internal combustion engine

Similar Documents

Publication Publication Date Title
JP2858288B2 (en) Self-diagnosis device in air-fuel ratio control device of internal combustion engine
JPS6213499B2 (en)
JPS6335825B2 (en)
JPH0253615B2 (en)
GB2252425A (en) Air-fuel ratio control apparatus for IC engine
JPS5925055A (en) Air-fuel ratio control device
JPH0531643B2 (en)
JPH0585742B2 (en)
JPH0312217B2 (en)
JP2927074B2 (en) Air-fuel ratio control device for internal combustion engine
JPS618438A (en) Method of controlling air-fuel ratio of internal combustion engine
JP3412350B2 (en) Knock determination device for internal combustion engine
JPH0316498B2 (en)
JP2715208B2 (en) Air-fuel ratio learning control device for internal combustion engine
JPH09324691A (en) Fuel control unit for combustion engine
US6901920B2 (en) Engine control apparatus having cylinder-by-cylinder feedback control
JP2712255B2 (en) Fuel supply control device for internal combustion engine
JPH0515552Y2 (en)
JPS60206953A (en) Air-fuel ratio control device in internal-combustion engine
JPH0733782B2 (en) Fuel injection control method
JPS6035148A (en) Air-fuel ratio control device
JPH0555704B2 (en)
JP3334453B2 (en) Catalyst deterioration detection device for internal combustion engine
JP2958595B2 (en) Air-fuel ratio feedback control device for internal combustion engine
JPS6045753A (en) Fuel controller of internal-combustion engine