JPH0429855B2 - - Google Patents
Info
- Publication number
- JPH0429855B2 JPH0429855B2 JP12590283A JP12590283A JPH0429855B2 JP H0429855 B2 JPH0429855 B2 JP H0429855B2 JP 12590283 A JP12590283 A JP 12590283A JP 12590283 A JP12590283 A JP 12590283A JP H0429855 B2 JPH0429855 B2 JP H0429855B2
- Authority
- JP
- Japan
- Prior art keywords
- air
- fuel ratio
- injection amount
- ratio feedback
- feedback 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.)
- Expired
Links
- 239000000446 fuel Substances 0.000 claims description 110
- 238000002347 injection Methods 0.000 claims description 64
- 239000007924 injection Substances 0.000 claims description 64
- 238000000034 method Methods 0.000 claims description 16
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 7
- 239000001301 oxygen Substances 0.000 description 7
- 229910052760 oxygen Inorganic materials 0.000 description 7
- 239000007789 gas Substances 0.000 description 6
- 230000008569 process Effects 0.000 description 5
- 239000003054 catalyst Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/04—Introducing corrections for particular operating conditions
- F02D41/12—Introducing corrections for particular operating conditions for deceleration
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)
Description
【発明の詳細な説明】
本発明は、電子制御燃料噴射式エンジンの空燃
比フイードバツク制御方式に係り、特に、空燃比
センサ及び三元触媒を用いて排気ガス浄化対策が
施された、電子制御燃料噴射装置を備えた自動車
用エンジンに用いるのに好適な、エンジン回転速
度及びエンジン負荷等から求められる燃料噴射量
に、設定空燃比と実空燃比の偏差に応じた空燃比
フイードバツク補正を加えて、要求噴射量を求め
るようにした電子制御燃料噴射式エンジンの空燃
比フイードバツク制御方法の改良に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air-fuel ratio feedback control system for an electronically controlled fuel injection engine, and particularly relates to an electronically controlled fuel injection engine in which exhaust gas purification measures are taken using an air-fuel ratio sensor and a three-way catalyst. Suitable for use in an automobile engine equipped with an injection device, the fuel injection amount determined from the engine speed, engine load, etc. is added with air-fuel ratio feedback correction according to the deviation between the set air-fuel ratio and the actual air-fuel ratio. The present invention relates to an improvement in an air-fuel ratio feedback control method for an electronically controlled fuel injection engine that determines a required injection amount.
内燃機関、特に、三元触媒を用いて排気ガス浄
化対策が施された自動車用エンジンにおいては、
排気空燃比を厳密に理論空燃比近傍に保持する必
要があり、そのため例えば、排気ガス中の酸素濃
度から排気空燃比のリツチ−リーン像体を感知す
る酸素濃度センサと、燃料噴射量を制御すること
によつて混合気の空燃比を制御する電子制御燃料
噴射装置とを備え、例えばエンジン回転速度及び
エンジン負荷等から求められる燃料噴射量に、前
記空燃比センサの出力に応じて判定される空燃比
のリツチ−リーン状態に応じた空燃比フイードバ
ツク補正を加えて、要求噴射量を求めることによ
り、前記電子制御燃料噴射装置の燃料噴射量、即
ち、空燃比をフイードバツク制御して、排気ガス
中の酸素濃度を、設定空燃比、例えば、理論空燃
比の混合気を燃焼させた場合の酸素濃度と等しく
するようにしたものが実用化されている。 Internal combustion engines, especially automobile engines that use three-way catalysts to purify exhaust gas,
It is necessary to maintain the exhaust air-fuel ratio strictly near the stoichiometric air-fuel ratio, so for example, an oxygen concentration sensor that detects the rich lean image of the exhaust air-fuel ratio from the oxygen concentration in the exhaust gas, and an oxygen concentration sensor that controls the fuel injection amount are used. and an electronically controlled fuel injection device that controls the air-fuel ratio of the air-fuel mixture. By adding air-fuel ratio feedback correction according to the rich-lean state of the fuel ratio and determining the required injection amount, the fuel injection amount of the electronically controlled fuel injection device, that is, the air-fuel ratio, is feedback-controlled, and the amount of fuel in the exhaust gas is A device in which the oxygen concentration is made equal to the oxygen concentration when a mixture at a set air-fuel ratio, for example, a stoichiometric air-fuel ratio is combusted, has been put into practical use.
このような空燃比フイードバツク制御によれ
ば、エンジン運転状態の変化に拘わらず、良好な
排気ガス浄化性能を得ることができるという特徴
を有する。 Such air-fuel ratio feedback control is characterized in that good exhaust gas purification performance can be obtained regardless of changes in engine operating conditions.
また、前記の電子制御燃料噴射装置において
は、通常、排気ガス浄化性能を向上すると共に、
燃料消費量を節減するため、エンジンの減速運転
時に、所定の燃料カツト条件が成立した場合に
は、燃料噴射量を零として、いわゆる燃料カツト
を行うようにされている。 Further, in the above-mentioned electronically controlled fuel injection device, usually, in addition to improving exhaust gas purification performance,
In order to reduce fuel consumption, when a predetermined fuel cut condition is met during deceleration operation of the engine, the fuel injection amount is set to zero to perform a so-called fuel cut.
しかしながら、前記燃料カツト条件が成立しな
い減速運転時には、第１図に実線Ａで示す如く、
要求噴射量Qaが、インジエクタの機械的又は電
気的な最小開弁時間により定まる最小噴射量Qb
以下となる場合がある。この場合、当該減速運転
時における燃料噴射量は、最小噴射量Qbで固定
され、その時の空燃比は、同じく第１図に実線Ａ
で示す如く、設定空燃比よりもリツチ側のままと
なる。従つて、この状態で空燃比フイードバツク
補正を実行すると、その補正係数FAFは、第１
図に実線Ａで示す如く、その下限値Ｄまで低下し
てしまう。従つて、エンジンが減速運転から再び
定常運転又は加速運転に移行した際に、空燃比フ
イードバツク補正係数FAFが適正値に戻るまで
の間、空燃比が、第１図に斜線Ｂで示す如く、一
時的にオーバーリーンとなり、排気エミツシヨン
が増加したり、ドライバビリテイが悪化するとい
う問題点を有していた。 However, during deceleration operation where the fuel cut condition is not satisfied, as shown by solid line A in FIG.
The required injection amount Qa is the minimum injection amount Qb determined by the minimum mechanical or electrical valve opening time of the injector.
The following may occur. In this case, the fuel injection amount during the deceleration operation is fixed at the minimum injection amount Qb, and the air-fuel ratio at that time is also shown by the solid line A in FIG.
As shown, the air-fuel ratio remains richer than the set air-fuel ratio. Therefore, if air-fuel ratio feedback correction is executed in this state, the correction coefficient FAF will be
As shown by the solid line A in the figure, it drops to its lower limit value D. Therefore, when the engine transitions from deceleration operation to steady operation or acceleration operation, the air-fuel ratio will temporarily change as shown by the diagonal line B in Fig. 1 until the air-fuel ratio feedback correction coefficient FAF returns to the appropriate value. However, the engine becomes over-lean, resulting in an increase in exhaust emissions and a deterioration in drivability.
このような問題点を解消すべく、定常運転から
減速運転に移行した際に、第１図に一点鎖線Ｃで
示す如く、空燃比フイードバツク補正係数FAF
を標準値1.0に固定して、減速運転時の空燃比フ
イードバツク補正を停止することも考えられる。
しかしながら、この場合には、空燃比フイードバ
ツク補正係数FAFが1.0以下の値から1.0迄増大さ
せることによつて、要求噴射量Qaが最小噴射量
Qbを越え、これにより空燃比フイードバツク補
正が再開されて、再び停止するという状態を繰返
すことになり、空燃比がハンチングして不安定に
なる恐れがあつた。 In order to solve this problem, when transitioning from steady operation to deceleration operation, the air-fuel ratio feedback correction coefficient FAF is adjusted as shown by the dashed line C in Figure 1.
It is also possible to fix the standard value to 1.0 and stop the air-fuel ratio feedback correction during deceleration operation.
However, in this case, by increasing the air-fuel ratio feedback correction coefficient FAF from a value of 1.0 or less to 1.0, the required injection amount Qa can be reduced to the minimum injection amount.
Qb was exceeded, and as a result, the air-fuel ratio feedback correction was restarted and stopped again, which caused the air-fuel ratio to become unstable due to hunting.
このような問題は、減速運転時だけでなく、高
地走行時にも発生する恐れがあつた。 Such problems could occur not only during deceleration driving but also when driving at high altitudes.
本発明は、前記従来の問題点を解決するべくな
されたもので、減速運転時や高地走行時における
空燃比を不安定化するとなく、減速運転や高地走
行から定常運転又は加速運転に移行した際に、迅
速に適正空燃比を得ることができる電子制御燃料
噴射式エンジンの空燃比フイードバツク制御方法
を提供することを目的とする。 The present invention has been made to solve the above-mentioned conventional problems, and does not destabilize the air-fuel ratio during deceleration driving or high-altitude driving, but when transitioning from decelerating driving or high-altitude driving to steady or accelerated driving. Another object of the present invention is to provide an air-fuel ratio feedback control method for an electronically controlled fuel injection engine that can quickly obtain an appropriate air-fuel ratio.
本発明は、エンジン回転速度及びエンジン負荷
等から求められる燃料噴射量に、設定空燃比と実
空燃比の偏差に応じた空燃比フイードバツク補正
を加えて、要求噴射量を求めるようにした電子制
御燃料噴射式エンジンの空燃比フイードバツク制
御方法において、第２図にその要旨を示す如く、
前記要求噴射量が、インジエクタの最小開弁時間
により定まる最小噴射量を越えているか否かを判
定する手順と、要求噴射量が最小噴射量を越えて
いる時は、空燃比フイードバツク補正係数の下限
値を通常値とするて手順と、要求噴射量が最小噴
射量以下である時は、空燃比フイードバツク補正
係数の下限値を前記通常値よりも大きな値とする
手順と、前記下限値により空燃比フイードバツク
補正係数の下限をガードする手順と、を含むこと
により、前記目的を達成したものである。 The present invention provides an electronically controlled fuel system that calculates the required injection amount by adding air-fuel ratio feedback correction according to the deviation between the set air-fuel ratio and the actual air-fuel ratio to the fuel injection amount calculated from the engine speed, engine load, etc. In the air-fuel ratio feedback control method for an injection type engine, as shown in Fig. 2,
The procedure for determining whether the required injection amount exceeds the minimum injection amount determined by the minimum valve opening time of the injector, and when the required injection amount exceeds the minimum injection amount, the lower limit of the air-fuel ratio feedback correction coefficient is determined. When the required injection amount is less than the minimum injection amount, the lower limit value of the air-fuel ratio feedback correction coefficient is set to a value larger than the normal value, and the lower limit value is set to the air-fuel ratio The above object is achieved by including the step of guarding the lower limit of the feedback correction coefficient.
本発明においては、要求噴射量が最小噴射量以
下である時は、空燃比フイードバツク補正係数の
下限値を、通常値よりも大きな値とするようにし
たので、減速運転時や高地走行時に空燃比フイー
ドバツク補正係数が異常に低下してしまうことが
なく、従つて、減速運転や高地走行から定常運転
又は加速運転に移行した際に、迅速に適正空燃比
を得ることができる。 In the present invention, when the required injection amount is less than the minimum injection amount, the lower limit value of the air-fuel ratio feedback correction coefficient is set to a value larger than the normal value. The feedback correction coefficient does not fall abnormally, and therefore, the appropriate air-fuel ratio can be quickly obtained when transitioning from deceleration driving or high-altitude driving to steady driving or accelerating driving.
以下図面を参照して、本発明に係る電子制御燃
料噴射式エンジンの空燃比フイードバツク制御方
法が採用された、吸気管圧力感知式の電子制御燃
料噴射装置を備えた自動車用エンジンの実施例を
詳細に説明する。 Below, with reference to the drawings, an embodiment of an automobile engine equipped with an intake pipe pressure sensing type electronically controlled fuel injection device in which the air-fuel ratio feedback control method for an electronically controlled fuel injection type engine according to the present invention is adopted will be described in detail. Explain.
本実施例は、第３図に示す如く、外部から吸入
される吸入空気の温度を検出するための吸気温セ
ンサ１２と、スロツトルボデイ１４に配設され、
運転席に配設されたアクセルペダル（図示省略）
と連動して開閉するようにされた、吸入空気の流
量を制御するためのスロツトル弁１６と、該スロ
ツトル弁１６の開度を検出するためのスロツトル
センサ１８と、吸気干渉を防止するためのサージ
タンク２０と、該サージタンク２０内の吸入空気
の圧力を検出するための吸気管圧力センサ２２
と、吸気マニホルド２４に配設された、エンジン
１０の各気筒の吸気ポートに向けて、加圧燃料を
間欠的に噴射するためのインジエクタ２６と、エ
ンジン燃焼室１０Ａ内に導入された混合気に着火
するための点火プラグ２８と、排気マニホルド３
０に配設された、排気空燃比のチツチ−リーン状
態を検出するための酸素濃度センサ（以下O2セ
ンサと称する）３１と、該O2センサ３１の下流
側に配設された、例えば三元触媒が充填された触
媒コンバータ３２と、点火コイル３３で発生され
た高圧の点火２次信号をエンジン１０の各気筒の
点火プラグ２８に配電するための、エンジン１０
のクランク軸の回転と連動して回転するデストリ
ビユータ軸３４Ａを有するデストリビユータ３４
と、該デストリビユータ３４に内蔵された、前記
デストリビユータ軸３４Ａの回転状態からエンジ
ン１０の回転状態を検知するためのクランク角度
センサ３６と、エンジン１０のシリンダブロツク
１０Ｂに配設された、エンジン冷却水温を検知す
るための温水センサ３８と、前記吸気管圧力セン
サ２２出力から検知されるエンジン負荷や前記ク
ランク角度センサ３６出力から求められるエンジ
ン回転速度等に応じて燃料噴射量を計算し、該燃
料噴射に、設定空燃比と実空燃比の偏差に応じた
空燃比フイードバツク補正を加えて要求噴射量を
計算し、該要求噴射量が得られよう前記インジエ
クタ２６に開弁時間信号を出力する電子制御ユニ
ツト（以下ECUと称する）４０と、から構成さ
れている。 In this embodiment, as shown in FIG. 3, an intake air temperature sensor 12 for detecting the temperature of intake air taken in from the outside and a throttle body 14 are provided.
Accelerator pedal located in the driver's seat (not shown)
A throttle valve 16 for controlling the flow rate of intake air, which is opened and closed in conjunction with the throttle valve 16, a throttle sensor 18 for detecting the opening degree of the throttle valve 16, and a throttle sensor 18 for preventing intake interference. A surge tank 20 and an intake pipe pressure sensor 22 for detecting the pressure of intake air in the surge tank 20
, an injector 26 disposed in the intake manifold 24 for intermittently injecting pressurized fuel toward the intake port of each cylinder of the engine 10; A spark plug 28 for ignition and an exhaust manifold 3
An oxygen concentration sensor (hereinafter referred to as an O 2 sensor) 31 for detecting a lean state of the exhaust air-fuel ratio, which is disposed at the The engine 10 has a catalytic converter 32 filled with a primary catalyst and a high-pressure ignition secondary signal generated by the ignition coil 33 for distributing power to the spark plugs 28 of each cylinder of the engine 10.
A distributor 34 having a distributor shaft 34A that rotates in conjunction with the rotation of the crankshaft.
, a crank angle sensor 36 built into the distributor 34 for detecting the rotational state of the engine 10 from the rotational state of the distributor shaft 34A, and a crank angle sensor 36 disposed in the cylinder block 10B of the engine 10 for detecting the engine cooling water temperature. The fuel injection amount is calculated according to the hot water sensor 38 for detection, the engine load detected from the output of the intake pipe pressure sensor 22, the engine rotational speed determined from the output of the crank angle sensor 36, etc. , an electronic control unit that calculates the required injection amount by adding air-fuel ratio feedback correction according to the deviation between the set air-fuel ratio and the actual air-fuel ratio, and outputs a valve opening time signal to the injector 26 so that the required injection amount is obtained. (hereinafter referred to as ECU) 40.
前記ECU４０は、第４図に詳細に示す如く、
各種演算処理を行うための、例えばマイクロプロ
セツサからなる中央処理ユニツト（以下CPUと
称する）４０Ａと、制御プログラムや各種データ
等を記憶するためのリードオンリーメモリ（以下
ROMと称する）４０Ｂと、前記CPU４０Ａにお
ける演算データ等を一時的に記憶するためのラン
ダムアクセスメモリ（以下RAMと称する）４０
Ｃと、前記吸気温センサ１２、吸気管圧力センサ
２２、O2センサ３１、水温センサ３８等から入
力されるアナログ信号をデジタル信号に変換して
順次取込むための、マルチプレクサ機能を備えた
アナログ−デジタル変換器（以下Ａ／Ｄコンバー
タと称する）４０Ｅと、前記スロツトルセンサ１
８、クランク角度センサ３６等から入力されるデ
ジタル信号を取込むとともに、CPU４０Ａの演
算結果に応じて、前記インジエクタ２６等に制御
信号を出力するための、バツフア機能を備えた入
出力ポート（以下Ｉ／Ｏポートと称する）４０Ｆ
と、前記各構成機器間を接続して、データや命令
を転送するためのコモンバス４０Ｇと、から構成
されている。 The ECU 40, as shown in detail in FIG.
A central processing unit (hereinafter referred to as CPU) 40A consisting of a microprocessor, for example, for performing various calculation processes, and a read-only memory (hereinafter referred to as CPU) for storing control programs and various data, etc.
a random access memory (hereinafter referred to as RAM) 40 for temporarily storing calculation data etc. in the CPU 40A;
C, and an analog device equipped with a multiplexer function for converting analog signals inputted from the intake air temperature sensor 12, intake pipe pressure sensor 22, O 2 sensor 31, water temperature sensor 38, etc. into digital signals and sequentially capturing them. A digital converter (hereinafter referred to as A/D converter) 40E and the throttle sensor 1
8. An input/output port (hereinafter referred to as I /O port) 40F
and a common bus 40G for connecting the respective component devices and transferring data and instructions.
以下作用を説明する。 The action will be explained below.
本実施例における空燃比フイードバツク補正係
数FAFの下限ガードは、第５図に示すような流
れ図に従つて実行される。即ち、まずステツプ
110で、前記クランク角度センサ３６出力から求
められるエンジン回転速度及び前記吸気管圧力セ
ンサ２２出力から求められる吸気管圧力等から、
エンジン１回転毎又は単位時間当りの燃料噴射量
を算出し、該燃料噴射量に、既に算出されてい
る、設定空燃比と実空燃比の偏差に応じた前回の
空燃比フイードバツク補正係数FAFを乗ずるこ
とによつて、今回の要求噴射量Qaを算出する。
ついでステツプ112に進み、前記O2センサ３１の
出力に応じて、今回の空燃比フイードバツク補正
係数FAFを算出する。ついでステツプ114に進
み、前出ステツプ110で算出された要求噴射量Qa
が、予め単体評価等で求められている、前記イン
ジエクタ２６の最小開弁時間により定まる最小噴
射量Qbを越えているか否かを判定する。判定結
果が正である場合、即ち、正確なフイードバツク
補正が行われていると判断される時には、ステツ
プ116に進み、空燃比フイードバツク補正係数の
下限値FAFminとして、通常値Ｄを入れる。一
方、前出ステツプ114の判定結果が否であり、正
確なフイードバツク補正が行われないと判断され
る時には、ステツプ118に進み、空燃比フイード
バツク補正係数の下限値FAFminとして、前記通
常値Ｄよりも大きな値Ｅ（Ｅ＞Ｄ）を入れる。こ
の値Ｅとしては、例えば、要求噴射量Qaと最小
噴射量Qbが略一致するような値とすることがで
きる。 In this embodiment, the lower limit guard of the air-fuel ratio feedback correction coefficient FAF is executed according to the flowchart shown in FIG. That is, first step
At 110, from the engine speed determined from the output of the crank angle sensor 36 and the intake pipe pressure determined from the output of the intake pipe pressure sensor 22,
Calculates the fuel injection amount per engine revolution or per unit time, and multiplies the fuel injection amount by the previous air-fuel ratio feedback correction coefficient FAF, which is already calculated and corresponds to the deviation between the set air-fuel ratio and the actual air-fuel ratio. Accordingly, the current required injection amount Qa is calculated.
Next, the process proceeds to step 112, in which the current air-fuel ratio feedback correction coefficient FAF is calculated according to the output of the O 2 sensor 31. The process then proceeds to step 114, where the required injection amount Qa calculated in step 110 is calculated.
It is determined whether or not the injection amount exceeds the minimum injection amount Qb determined by the minimum valve opening time of the injector 26, which is determined in advance by unit evaluation or the like. If the determination result is positive, that is, if it is determined that accurate feedback correction is being performed, the process proceeds to step 116, where the normal value D is entered as the lower limit value FAFmin of the air-fuel ratio feedback correction coefficient. On the other hand, if the judgment result in step 114 is negative and it is determined that accurate feedback correction is not performed, the process proceeds to step 118, where the lower limit value FAFmin of the air-fuel ratio feedback correction coefficient is set to be lower than the normal value D. Enter a large value E (E>D). This value E can be, for example, a value such that the required injection amount Qa and the minimum injection amount Qb substantially match.
前出ステツプ116又は118終了後、ステツプ120
に進み、その時の下限値FAFminにより、空燃比
フイードバツク補正係数FAFの下限値をガート
して、このルーチンを終了する。 After completing step 116 or 118 above, step 120
Then, the lower limit value of the air-fuel ratio feedback correction coefficient FAF is set to the lower limit value FAFmin at that time, and this routine ends.
このルーチンによつて決定された空燃比フイー
ドバツク補正係数FAFは、次回の要求噴射量Qa
の算出の際に用いられる。 The air-fuel ratio feedback correction coefficient FAF determined by this routine is the next required injection amount Qa.
Used when calculating.
本実施例における、定常運転から減速運転に移
行し、再び定常運転に戻つた際の空燃比フイード
バツク補正係数FAF、要求噴射量Qa、空燃比の
変化状態の一例を、前出第１図に破線Ｆで示す。
図から明らかな如く、本実施例においては、減速
運転時の空燃比フイードバツク補正係数FAFが、
通常値Ｄよりも大きな値Ｅでガードされるため、
再び定常運転に復帰した際に、空燃比フイードバ
ツク補正係数FAFが迅速にフイードバツク制御
領域まで戻り、第１図に実線Ａで示した従来例の
ような、大きなオーバーリーン領域Ｂが解消され
る。又、同じく第１図に一点鎖線Ｃで示した比較
例のように、減速運転時に空燃比がハンチングし
て不安定になることもない。 In this example, an example of the change state of the air-fuel ratio feedback correction coefficient FAF, the required injection amount Qa, and the air-fuel ratio when shifting from steady operation to deceleration operation and returning to steady operation is shown in the broken line in Fig. 1 above. Indicated by F.
As is clear from the figure, in this embodiment, the air-fuel ratio feedback correction coefficient FAF during deceleration operation is
Because it is guarded with a value E larger than the normal value D,
When normal operation is resumed, the air-fuel ratio feedback correction coefficient FAF quickly returns to the feedback control region, and the large over-lean region B shown in the conventional example shown by the solid line A in FIG. 1 is eliminated. Further, unlike the comparative example shown by the dashed line C in FIG. 1, the air-fuel ratio does not become unstable due to hunting during deceleration operation.
本実施例においては、空燃比フイードバツク補
正係数の下限値FAFminを２値としていたので、
プログラムが単純である。なお空燃比フイードバ
ツク補正係数の下限値を変える方法はこれに限定
されず、例えば３値以上とすることも可能であ
る。 In this embodiment, since the lower limit value FAFmin of the air-fuel ratio feedback correction coefficient is set to two values,
The program is simple. Note that the method of changing the lower limit value of the air-fuel ratio feedback correction coefficient is not limited to this, and it is also possible to set it to three or more values, for example.
前記実施例においては、本発明が、吸気管圧力
感知式の電子制御燃料噴射装置を備えた自動車用
エンジンに適用されていたが、本発明の適用範囲
はこれに限定されず、例えば、吸入空気量感知式
の電子制御燃料噴射装置を備えた自動車用エンジ
ンや、他の型式の電子制御燃料噴射式エンジンに
も同様に適用できることは明らかである。 In the above embodiments, the present invention was applied to an automobile engine equipped with an electronically controlled fuel injection device that senses intake pipe pressure. However, the scope of application of the present invention is not limited thereto. It is clear that the present invention is equally applicable to automobile engines with volume-sensitive electronically controlled fuel injection systems and to other types of electronically controlled fuel injection engines.
以上説明した通り、本発明によれば、減速運転
時や高地走行時における空燃比を不安定化するこ
となく、減速運転や高地走行から定常運転又は加
速運転に移行した際に、迅速に適正な空燃比を得
ることができる。従つて、その際の排気エミツシ
ヨンを低減すると共に、ドライバビリテイを向上
することができるという優れた効果を有する。 As explained above, according to the present invention, the air-fuel ratio is not destabilized during deceleration driving or high-altitude driving, and when transitioning from decelerating driving or high-altitude driving to steady or accelerated driving, the air-fuel ratio can be quickly adjusted to the appropriate level. The air-fuel ratio can be obtained. Therefore, it has the excellent effect of reducing exhaust emissions at that time and improving drivability.
第１図は、従来例、比較例及び本発明の実施例
における、定常運転から減速運転に移行し、再び
定常運転に復帰した際の、空燃比フイードバツク
補正係数、要求噴射量、空燃比の変化状態の関係
の例を比較して示す線図、第２図は、本発明に係
る電子制御燃料噴射式エンジンの空燃比フイード
バツク制御方法の要旨を示す流れ図、第３図は、
本発明が採用された、吸気管圧力感知式の電子制
御燃料噴射装置を備えた自動車用エンジンの実施
例の構成を示す、一部ブロツク線図を含む断面
図、第４図は、前記実施例で用いられている電子
制御ユニツトの構成を示すブロツク線図、第５図
は、同じく、空燃比フイードバツク補正係数の下
限ガードを行うためのルーチンの要部を示す流れ
図である。
Qa……要求噴射量、Qb……最小噴射量、FAF
……空燃比フイードバツク補正係数、FAFmin…
…下限値、Ｄ……通常値、Ｅ……通常値よりも大
きな値、１０……エンジン、２２……吸気管圧力
センサ、２６……インジエクタ、３１……酸素濃
度センサ（O2センサ）、３２……触媒コンバー
タ、３６……クランク角度センサ、４０……電子
制御ユニツト（ECU）。
FIG. 1 shows changes in the air-fuel ratio feedback correction coefficient, required injection amount, and air-fuel ratio when shifting from steady operation to deceleration operation and returning to steady operation again in a conventional example, a comparative example, and an example of the present invention. FIG. 2 is a diagram showing a comparison of examples of state relationships; FIG. 2 is a flow chart showing the gist of the air-fuel ratio feedback control method for an electronically controlled fuel injection engine according to the present invention;
FIG. 4 is a cross-sectional view, partially including a block diagram, showing the configuration of an embodiment of an automobile engine equipped with an electronically controlled fuel injection device of intake pipe pressure sensing type, in which the present invention is adopted. FIG. 5 is a block diagram showing the configuration of the electronic control unit used in the system. Similarly, FIG. 5 is a flowchart showing the main part of the routine for guarding the lower limit of the air-fuel ratio feedback correction coefficient. Qa...Required injection amount, Qb...Minimum injection amount, FAF
...Air-fuel ratio feedback correction coefficient, FAFmin...
... Lower limit value, D ... Normal value, E ... Value larger than normal value, 10 ... Engine, 22 ... Intake pipe pressure sensor, 26 ... Injector, 31 ... Oxygen concentration sensor (O 2 sensor), 32...Catalytic converter, 36...Crank angle sensor, 40...Electronic control unit (ECU).
Claims (1)
めらる燃料噴射量に、設定空燃比と実空燃比の偏
差に応じた空燃比フイードバツク補正を加えて、
要求噴射量を求めるようにした電子制御燃料噴射
式エンジンの空燃比フイードバツク制御方法にお
いて、前記要求噴射量が、インジエクタの最小開
弁時間により定まる最小噴射量を越えているか否
かを判定する手順と、要求噴射量が最小噴射量を
越えている時は、空燃比フイードバツク補正係数
の下限値を通常値とする手順と、要求噴射量が最
小噴射量以下である時は、空燃比フイードバツク
補正係数の下限値を前記通常値よりも大きな値と
する手順と、前記下限値により空燃比フイードバ
ツク補正係数の下限をガードする手順と、を含む
ことを特徴とする電子制御燃料噴射式エンジンの
空燃比フイードバツク制御方法。1 Add air-fuel ratio feedback correction according to the deviation between the set air-fuel ratio and the actual air-fuel ratio to the fuel injection amount determined from the engine speed and engine load, etc.
In an air-fuel ratio feedback control method for an electronically controlled fuel injection engine that determines a required injection amount, the method includes: determining whether the required injection amount exceeds a minimum injection amount determined by a minimum valve opening time of an injector; When the required injection amount exceeds the minimum injection amount, the lower limit value of the air-fuel ratio feedback correction coefficient is set to the normal value, and when the required injection amount is less than the minimum injection amount, the procedure is to set the air-fuel ratio feedback correction coefficient to the normal value. Air-fuel ratio feedback control for an electronically controlled fuel injection engine, characterized in that it includes the steps of: setting a lower limit value to a value larger than the normal value; and guarding the lower limit of the air-fuel ratio feedback correction coefficient using the lower limit value. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12590283A JPS6019942A (en) | 1983-07-11 | 1983-07-11 | Method of feedback control of air-fuel ratio of electronically controlled fuel injection engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12590283A JPS6019942A (en) | 1983-07-11 | 1983-07-11 | Method of feedback control of air-fuel ratio of electronically controlled fuel injection engine |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6019942A JPS6019942A (en) | 1985-02-01 |
| JPH0429855B2 true JPH0429855B2 (en) | 1992-05-20 |
Family
ID=14921731
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12590283A Granted JPS6019942A (en) | 1983-07-11 | 1983-07-11 | Method of feedback control of air-fuel ratio of electronically controlled fuel injection engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6019942A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58215466A (en) * | 1982-06-08 | 1983-12-14 | Honny Chem Ind Co Ltd | Matte electrodeposition coating method |
| JPS6332140A (en) * | 1986-07-28 | 1988-02-10 | Mazda Motor Corp | Air-fuel ratio controller for engine |
-
1983
- 1983-07-11 JP JP12590283A patent/JPS6019942A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6019942A (en) | 1985-02-01 |
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