JPH04334736A - Air fuel ratio control device for internal combustion engine - Google Patents

Air fuel ratio control device for internal combustion engine

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Publication number
JPH04334736A
JPH04334736A JP3105810A JP10581091A JPH04334736A JP H04334736 A JPH04334736 A JP H04334736A JP 3105810 A JP3105810 A JP 3105810A JP 10581091 A JP10581091 A JP 10581091A JP H04334736 A JPH04334736 A JP H04334736A
Authority
JP
Japan
Prior art keywords
fuel ratio
air
fuel
internal combustion
combustion engine
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP3105810A
Other languages
Japanese (ja)
Inventor
Shigeyuki Hori
重之 堀
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 JP3105810A priority Critical patent/JPH04334736A/en
Publication of JPH04334736A publication Critical patent/JPH04334736A/en
Pending legal-status Critical Current

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  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

PURPOSE:To prevent preignition by controlling a fuel increasing amount according to the temperature of exhaust gas. CONSTITUTION:An air fuel ratio sensor is provided in an exhaust system, and a control circuit is provided in order to control the valve opening time of an injector by the air fuel ratio signal outputted from the air fuel ratio sensor. A basic injection amount tauBASE is calculated according to a load and a rotational speed (step 50), and a feed-back correction coefficient FAF is increased/ decreased by an air fuel ratio signal outputted from the air fuel ratio sensor 38 at the time of operation of feed back (yes at step 52), then the feed back correction coefficient is multiplication-corrected by the basic injection amount tauBASE (step 70). Under non-feed back condition (No at step 52), the temperature(Te) of exhaust gas is measured, and a fuel injection amount is increasing- corrected (step 58) by a increasing correction coefficient tau0 in the case where it exceeds a prescribed value Tmax (yes at step 56). It is thus possible to prevent dilution by increasing-correction, and also prevent preignition.

Description

【発明の詳細な説明】[Detailed description of the invention]

【0001】0001

【産業上の利用分野】この発明は内燃機関、特にアルコ
ール系燃料を使用する内燃機関における空燃比制御装置
に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an air-fuel ratio control device for an internal combustion engine, particularly an internal combustion engine using alcohol-based fuel.

【0002】0002

【従来の技術】メタノール等のアルコール系燃料を使用
する内燃機関(例えば、特開平2−185634号) 
ではガソリンのみを燃料として使用する場合より燃料系
統、特にインジェクタの詰まりが発生しやすい。即ち、
メタノールは溶剤となり配管やシール等に使用されるゴ
ム等を溶解せしめる上、沸点が65°程度と低く容易に
蒸発するため、溶解したものがデポジットになり易いの
である。燃料系統の詰まりによって一定時間に噴射され
る燃料の量が少なくなる。空燃比のフィードバック制御
を実施している場合は燃料量が少なくなると空燃比を検
出することによりインジェクタの噴射時間を長くするよ
うな修正が行われるため、空燃比は本来の値に制御され
る。
[Prior Art] Internal combustion engine that uses alcohol-based fuel such as methanol (for example, Japanese Patent Application Laid-Open No. 2-185634)
In this case, the fuel system, especially the injector, is more likely to become clogged than when only gasoline is used as fuel. That is,
Methanol acts as a solvent and dissolves rubber used for piping, seals, etc., and also has a low boiling point of about 65° and evaporates easily, so the dissolved material tends to become deposits. A blockage in the fuel system reduces the amount of fuel injected in a given period of time. When feedback control of the air-fuel ratio is performed, when the amount of fuel decreases, the air-fuel ratio is detected and a correction is made to lengthen the injection time of the injector, so the air-fuel ratio is controlled to the original value.

【0003】0003

【発明が解決しようとする課題】空燃比のフィードバッ
ク制御はエンジンの高負荷時、ときにはアイドル運転時
には停止される。この場合空燃比はなりゆきとなり、つ
まりが発生している場合は空燃比は所望値より希薄側に
ずれる。空燃比が希薄側にずれるとアルコール燃料の場
合は過早着火(プレイグニッション)がおこる問題があ
った。
Feedback control of the air-fuel ratio is stopped when the engine is under high load, sometimes when the engine is idling. In this case, the air-fuel ratio remains as it is, and if clogging occurs, the air-fuel ratio deviates from the desired value to the lean side. If the air-fuel ratio deviates to the lean side, there is a problem that premature ignition (pre-ignition) occurs in the case of alcohol fuel.

【0004】0004

【課題を解決するための手段】この発明によれば、図1
に示すように、内燃機関の負荷及び回転数で決まる基本
燃料供給量を算出する手段Aと、空燃比のフィードバッ
ク制御を行う運転条件を検出する手段Bと、空燃比フィ
ードバック条件時に所望の空燃比が得られるように基本
燃料供給量に補正を加える手段Cと、フィードバック補
正された量の燃料を内燃機関に供給する手段Dとを具備
した内燃機関の空燃比制御装置において、内燃機関の排
気温度を検出する手段Eと、空燃比のフィードバック制
御を行わない運転時において排気温度が所定値以上のと
き燃料供給手段Dから内燃機関に供給される燃料量を基
本燃料供給量に対して増量補正する手段Fとを具備する
内燃機関の空燃比制御装置が提供される。
[Means for Solving the Problems] According to this invention, FIG.
As shown in the figure, means A calculates the basic fuel supply amount determined by the load and rotational speed of the internal combustion engine, means B detects the operating conditions for performing air-fuel ratio feedback control, and detects the desired air-fuel ratio under the air-fuel ratio feedback condition. In an air-fuel ratio control device for an internal combustion engine, the air-fuel ratio control device for an internal combustion engine includes means C for correcting the basic fuel supply amount so as to obtain and means E for detecting the amount of fuel supplied from the fuel supply means D to the internal combustion engine when the exhaust temperature is equal to or higher than a predetermined value during operation without air-fuel ratio feedback control. An air-fuel ratio control device for an internal combustion engine is provided, comprising means F.

【0005】[0005]

【作用】基本燃料供給量算出手段Aは、内燃機関の負荷
及び回転数で決まる基本燃料供給量を算出し、空燃比フ
ィードバック条件検出手段Bは空燃比のフィードバック
制御を行う運転条件を検出し、フィードバック補正量算
出手段Cは、空燃比フィードバック条件検出手段Bが空
燃比フィードバック条件と検出した時に所望の空燃比が
得られるように基本燃料供給量に補正を加える。燃料供
給手段Dは、フィードバック補正された量の燃料を内燃
機関に供給する。
[Operation] The basic fuel supply amount calculation means A calculates the basic fuel supply amount determined by the load and rotation speed of the internal combustion engine, and the air-fuel ratio feedback condition detection means B detects the operating conditions for performing feedback control of the air-fuel ratio, The feedback correction amount calculation means C corrects the basic fuel supply amount so that a desired air-fuel ratio is obtained when the air-fuel ratio feedback condition detection means B detects the air-fuel ratio feedback condition. The fuel supply means D supplies a feedback-corrected amount of fuel to the internal combustion engine.

【0006】排気温度検出手段Dは内燃機関の排気温度
を検出し、排気温度補正量算出手段Fは、空燃比フィー
ドバック条件検出手段Bにより空燃比のフィードバック
制御を行わない運転時と検出した時において、排気温度
検出手段Eにより検出される排気温度が所定値以上のと
き燃料供給手段Dから内燃機関に供給される燃料量を基
本燃料供給量に対して増量補正する。
The exhaust temperature detection means D detects the exhaust gas temperature of the internal combustion engine, and the exhaust temperature correction amount calculation means F detects when the air-fuel ratio feedback condition detection means B detects that the air-fuel ratio feedback control is not performed. When the exhaust temperature detected by the exhaust temperature detection means E is equal to or higher than a predetermined value, the amount of fuel supplied from the fuel supply means D to the internal combustion engine is corrected to increase the basic fuel supply amount.

【0007】[0007]

【実施例】第2図はアルコールを燃料とする電子制御燃
料噴射内燃機関を示しており、10はエンジン本体、1
2は吸気管、14はエアフローメータ、16はスロット
ル弁、18は排気管、20はディストリビュータ、22
は点火栓、24はイグナイタ付の点火コイルを示す。イ
ンジェクタ26は各気筒毎にその吸気ポートに開口する
ように設けられ、燃料デリバリパイプ28を介して図示
しない燃料タンクに接続され、燃料としてのアルコール
はインジェクタ26より各気筒の吸気ポートに噴射され
る。
[Embodiment] Fig. 2 shows an electronically controlled fuel injection internal combustion engine that uses alcohol as fuel.
2 is an intake pipe, 14 is an air flow meter, 16 is a throttle valve, 18 is an exhaust pipe, 20 is a distributor, 22
24 indicates an ignition plug, and 24 indicates an ignition coil with an igniter. The injector 26 is provided to open into the intake port of each cylinder, and is connected to a fuel tank (not shown) via a fuel delivery pipe 28, and alcohol as fuel is injected from the injector 26 into the intake port of each cylinder. .

【0008】制御回路30はマイクロコンピュータシス
テムとして構成され、各センサからのエンジン運転状態
信号より燃料噴射量の演算を行い、燃料インジェクタ2
6より必要な量の燃料を噴射せしめる。また、この発明
と直接には関係しない点火時期の演算を実行し、演算さ
れたタイミング点火信号を点火コイル24のイグナイタ
に出力し、ディストリビュータ20によって決められる
気筒の点火制御を実行する。
The control circuit 30 is configured as a microcomputer system, and calculates the fuel injection amount from the engine operating status signals from each sensor, and controls the fuel injector 2.
6, inject the required amount of fuel. It also performs calculation of ignition timing, which is not directly related to the present invention, outputs the calculated timing ignition signal to the igniter of the ignition coil 24, and performs ignition control of the cylinder determined by the distributor 20.

【0009】エアフローメータ14は吸入空気量に応じ
た信号を制御回路30に入力する。クランク角度センサ
34,36 がディストリビュータ20に設けられ、ク
ランク角度で30°毎のパルス信号と、720 °毎の
パルス信号を発生する。空燃比センサ38は排気管に設
けられ、空燃比の検出を行うことができる。また、排気
ガス温度センサ40が排気管18に設けられ、排気ガス
の温度を知ることができる。
The air flow meter 14 inputs a signal corresponding to the intake air amount to the control circuit 30. Crank angle sensors 34, 36 are provided in the distributor 20 and generate pulse signals every 30 degrees and every 720 degrees of crank angle. The air-fuel ratio sensor 38 is provided in the exhaust pipe and can detect the air-fuel ratio. Further, an exhaust gas temperature sensor 40 is provided in the exhaust pipe 18, so that the temperature of the exhaust gas can be detected.

【0010】図3, 4は制御回路30によって実行さ
れる制御のうちこの発明に関連する空燃比制御の部分を
フローチャートにて示す。図3は燃料噴射ルーチンで、
このルーチンは各気筒の燃料噴射タイミング毎に実行さ
れ、この燃料噴射タイミングか否かはクランク角度セン
サ34からのクランク角度で720 °毎のパルス信号
の到来によってクリヤされ、クランク角度センサ36か
らの30°CA毎のパルス信号によってインクリメント
されるカウンタの値によって知ることができる。
FIGS. 3 and 4 are flowcharts showing the air-fuel ratio control portion of the control executed by the control circuit 30, which is relevant to the present invention. Figure 3 shows the fuel injection routine.
This routine is executed at each fuel injection timing for each cylinder, and whether or not this fuel injection timing is reached is cleared by the arrival of a pulse signal every 720 degrees at the crank angle from the crank angle sensor 34, and the pulse signal from the crank angle sensor 36 at every 720 degrees is cleared. This can be determined by the value of a counter that is incremented by a pulse signal every °CA.

【0011】ステップ50は基本噴射量τBASEの算
出を示し、このτBASEはその負荷(吸入空気量−エ
ンジン回転数比)及び回転数での設定空燃比を得ること
ができるインジェクタ26の開弁時間として設定される
。ステップ52ではフィードバックフラグFB=1か否
か判別される。FBは空燃比のフィードバック制御実行
時に1となり、フィードバック制御非実行時に0となる
。フィードバック制御時はステップ54に進み、τ0 
を零にする。τ0 はフィードバック制御を実行してい
ないとき(オープンループ制御実行時)に、希薄化によ
るプレイグニッションの防止のため排気温度を一定に維
持するための補正増量である。フィードバック制御時に
はこの補正を行う必要がないのでステップ54でτ0 
=0とされる。
[0011] Step 50 shows calculation of the basic injection amount τBASE, and this τBASE is expressed as the valve opening time of the injector 26 that can obtain the set air-fuel ratio at the load (intake air amount - engine rotational speed ratio) and rotational speed. Set. In step 52, it is determined whether the feedback flag FB=1. FB becomes 1 when air-fuel ratio feedback control is executed, and becomes 0 when feedback control is not executed. During feedback control, proceed to step 54, and τ0
to zero. τ0 is a correction increase for maintaining the exhaust temperature constant in order to prevent pre-ignition due to dilution when feedback control is not being executed (open loop control is being executed). Since there is no need to perform this correction during feedback control, τ0 is determined in step 54.
=0.

【0012】ステップ52でFB=0、即ちフィードバ
ック制御が行われていないと判断したときはステップ5
6〜62の処理が実行されるが、これについては後で説
明する。ステップ70は最終的に噴射される燃料噴射量
τが、τ=τBASE×FAF ×(1+α) ×β+
τ0 +γによって算出される。ここに、FAF は後
述のフィードバック補正係数であり、α, β, γは
この発明と直接に関係しないため詳細説明を省略する補
正係数、補正量を概括的に意味する。ステップ74では
ステップ70で計算される燃料噴射量に応じた時間イン
ジェクタ26が開弁されるように燃料噴射信号がインジ
ェクタ26に供給される。
If it is determined in step 52 that FB=0, that is, feedback control is not being performed, step 5
Processes 6 to 62 are executed, which will be explained later. In step 70, the final fuel injection amount τ is calculated as follows: τ=τBASE×FAF×(1+α)×β+
It is calculated by τ0 + γ. Here, FAF is a feedback correction coefficient to be described later, and α, β, and γ generally mean correction coefficients and correction amounts whose detailed explanation will be omitted because they are not directly related to the present invention. In step 74, a fuel injection signal is supplied to the injector 26 so that the injector 26 is opened for a time corresponding to the fuel injection amount calculated in step 70.

【0013】図4はフィードバックルーチンであり、一
定時間毎(例えば10ミリ秒毎) に実行される。ステ
ップ76ではエンジンの暖機中か、ステップ78ではエ
ンジンの高負荷運転域か否か判別される。暖機運転中又
は高負荷運転時はステップ80に進み、フィードバック
フラグFB=0にリセットされ、ステップ82ではフィ
ードバック補正係数FAF=1.0 とされ、燃料噴射
量に対するフィードバック補正は加わらない。即ち、空
燃比のフィードバック制御は行われない。
FIG. 4 shows a feedback routine, which is executed at regular intervals (for example, every 10 milliseconds). In step 76, it is determined whether the engine is being warmed up, and in step 78, it is determined whether the engine is in a high-load operating range. During warm-up or high-load operation, the process proceeds to step 80, where the feedback flag FB is reset to 0, and in step 82, the feedback correction coefficient FAF is set to 1.0, and no feedback correction is applied to the fuel injection amount. That is, feedback control of the air-fuel ratio is not performed.

【0014】完全暖機後でかつ高負荷時でないフィード
バック条件ではステップ78よりステップ84に進み、
フィードバックフラグFB=1とセットされ、以下のフ
ィードバック処理が行われる。ステップ86では空燃比
センサ38によって計測される空燃比が設定空燃比より
リッチか否か判別され、リッチ側にずれていると判定さ
れるときはステップ88に進み、スキップ点か否かの判
定が行われる。リーン判断からリッチ判断への切り替わ
りのときはスキップを行うため、ステップ90に進み、
フィードバック補正係数FAF は比例補正量LSだけ
減少される。2回目以降のリッチ判断のときはステップ
92に進み、フィードバック補正係数FAF は積分補
正量ls(<<LS)だけ減少される。ステップ86で
リーン側にずれていると判定されるときはステップ94
に進み、スキップ点か否かの判定が行われる。リッチ判
断からリーン判断への切り替わりのときはスキップを行
うため、ステップ96に進み、フィードバック補正係数
FAF は比例補正量RSだけ増加される。2回目以降
のリーン判断のときはステップ98に進み、フィードバ
ック補正係数FAF は積分補正量rs(<<RS)だ
け増大される。
Under the feedback condition after complete warm-up and not under high load, the process proceeds from step 78 to step 84;
The feedback flag FB is set to 1, and the following feedback processing is performed. In step 86, it is determined whether or not the air-fuel ratio measured by the air-fuel ratio sensor 38 is richer than the set air-fuel ratio. If it is determined that the air-fuel ratio is deviated to the rich side, the process proceeds to step 88, where it is determined whether or not the skip point is reached. It will be done. In order to skip when switching from lean judgment to rich judgment, proceed to step 90,
The feedback correction coefficient FAF is reduced by the proportional correction amount LS. At the second or subsequent rich determination, the process proceeds to step 92, where the feedback correction coefficient FAF is decreased by the integral correction amount ls (<<LS). If it is determined in step 86 that the shift is toward the lean side, step 94
Then, it is determined whether the point is a skip point or not. Since a skip is performed when switching from rich judgment to lean judgment, the process proceeds to step 96, where the feedback correction coefficient FAF is increased by the proportional correction amount RS. When the lean judgment is made for the second time or later, the process proceeds to step 98, and the feedback correction coefficient FAF is increased by the integral correction amount rs (<<RS).

【0015】アルコールを含む燃料を使用した場合、イ
ンジェクタ26内のバルブシートの部分やバルブの部分
にデポジットが発生し、これは通路径を絞ることになり
、燃料インジェクタの開弁時間に対する燃料噴射量を少
なくする。ステップ50で算出される基本噴射量τBA
SEは燃料噴射量と開弁時間との一定の関係を想定する
から、つまりによって開弁時間に対する燃料噴射量が少
なくなると、燃料噴射量は意図した値には足りなくなる
。フィードバック制御が行われている場合はフィードバ
ック補正係数FAF によって空燃比は定常状態では所
期の値に制御される。ところが、フィードバック制御が
行われていない場合はフィードバック補正係数FAF 
=1に固定されるため(ステップ82) 、燃料噴射量
は本来の空燃比を得る値よりは少ないままでである。空
燃比が希薄となることによってプレイグニッションが発
生しやすくなる。即ち、図5(イ) は空燃比とプレイ
グニッションに対する余裕度との関係を概略的に図示し
ており、理論空燃比付近でプレイグニッション余裕度は
最小となり、理論空燃比よりリッチとなってもリーンと
なってもプレイグニッションに対する余裕は大きくなる
。そして、フィードバックを行わない高負荷時は所期の
空燃比は破線mのように理論空燃比より幾分リッチ側の
空燃比である。従って、空燃比がリーン側にずれると(
図5(イ) の破線の右の方向)2点鎖線nのように理
論空燃比に近づくことになり、プレイグニッションに対
する余裕は小さくなり、プレイグニッションが起こりや
すくなる。この発明ではこのようなプレイグニッション
を惹起せしめるインジェクタの流量低下を排気ガスの温
度によって検出している。 即ち、図5の(ロ) は空燃比と排気温度との関係を示
しており、リッチ側の空燃比の範囲では排気温度は理論
空燃比に近づくに従って高くなる。従って、排気温度は
空燃比を介して燃料系統のデポジットと関連しており、
排気温度を知ることによりインジェクタの流量低下を把
握し、これを燃料噴射量に反映させれば、排気ガス温度
の増大を防止し、ひいてはプレイグニッションを防止を
することができる。
[0015] When fuel containing alcohol is used, deposits are generated on the valve seat and valve parts of the injector 26, which reduces the passage diameter and reduces the amount of fuel injected relative to the valve opening time of the fuel injector. Reduce. Basic injection amount τBA calculated in step 50
Since SE assumes a constant relationship between the fuel injection amount and the valve opening time, if the fuel injection amount decreases with respect to the valve opening time, the fuel injection amount will be insufficient to the intended value. When feedback control is performed, the air-fuel ratio is controlled to a desired value in a steady state by the feedback correction coefficient FAF. However, if feedback control is not performed, the feedback correction coefficient FAF
= 1 (step 82), the fuel injection amount remains smaller than the value that provides the original air-fuel ratio. As the air-fuel ratio becomes leaner, pre-ignition becomes more likely to occur. In other words, Figure 5 (a) schematically shows the relationship between the air-fuel ratio and the margin for pre-ignition, and the pre-ignition margin becomes minimum near the stoichiometric air-fuel ratio, and even when the air-fuel ratio is richer than the stoichiometric one, the pre-ignition margin becomes minimum. Even when the engine is lean, there is more room for pre-ignition. When the load is high and no feedback is performed, the intended air-fuel ratio is an air-fuel ratio that is somewhat richer than the stoichiometric air-fuel ratio, as indicated by the broken line m. Therefore, if the air-fuel ratio shifts to the lean side (
In the direction to the right of the broken line in FIG. 5(a)), the air-fuel ratio approaches the stoichiometric air-fuel ratio as indicated by the two-dot chain line n, and the margin for pre-ignition becomes smaller, making pre-ignition more likely to occur. In the present invention, a decrease in the flow rate of the injector that causes such pre-ignition is detected based on the temperature of the exhaust gas. That is, (b) in FIG. 5 shows the relationship between the air-fuel ratio and the exhaust gas temperature, and in the rich side air-fuel ratio range, the exhaust temperature increases as it approaches the stoichiometric air-fuel ratio. Therefore, exhaust temperature is related to fuel system deposits via air/fuel ratio;
By knowing the exhaust gas temperature, it is possible to grasp the decrease in the flow rate of the injector and reflect this in the fuel injection amount, thereby preventing an increase in the exhaust gas temperature and, in turn, preventing pre-ignition.

【0016】図3のステップ56〜62は排気ガス温度
による燃料噴射量の制御ルーチンに対応しており、フィ
ードバック条件でないと判断したときステップ52より
ステップ56に進み、排気ガス温度Tex<Tmax 
か否か判別される。Tex≧Tmax と判定されると
きはステップ58に進み、排気温度による増量値τ0 
がaだけ増大される。即ち、インジェクタの流量低下が
あると空燃比はリーン側にずれ、排気温度が増大するこ
とから、排気温度が高い状態をインジェクタの流量低下
状態と捉えることができる。燃料噴射量を増量すること
で、空燃比の希薄側へのずれを解消し、排気ガス温度を
降下させることができる。排気温度が所定最大値Tma
xより下がった場合は、ステップ56よりステップ60
に進み、ステップ60でτ0 ≦0と判定されない限り
はステップ62に進み、τ0 がbだけ減少される。
Steps 56 to 62 in FIG. 3 correspond to a routine for controlling the fuel injection amount based on the exhaust gas temperature, and when it is determined that there is no feedback condition, the process proceeds from step 52 to step 56, and if the exhaust gas temperature Tex<Tmax
It is determined whether or not. When it is determined that Tex≧Tmax, the process proceeds to step 58, and the increase value τ0 due to the exhaust temperature is determined.
is increased by a. That is, when there is a decrease in the flow rate of the injector, the air-fuel ratio shifts to the lean side and the exhaust gas temperature increases, so a state where the exhaust gas temperature is high can be regarded as a state where the flow rate of the injector is decreased. By increasing the fuel injection amount, it is possible to eliminate the deviation of the air-fuel ratio toward the lean side and lower the exhaust gas temperature. Exhaust temperature reaches predetermined maximum value Tma
If it falls below x, step 56 to step 60
Unless it is determined in step 60 that τ0 ≦0, the process advances to step 62, where τ0 is decreased by b.

【0017】以上の実施例では高負荷時にフィードバッ
クを行わないものについて説明したが、外の運転時、例
えばアイドル時にフィードバックを行わないものについ
ても同様に排気温度を介して流量低下に原因する空燃比
の変化を知り、これを燃料噴射量に反映させることで空
燃比非フィードバック時の空燃比のずれによるプレイグ
ニッションの防止を図ることができる。
[0017] In the above embodiments, an example in which feedback is not performed during high load has been described, but in an example in which feedback is not performed during outside operation, for example, when idling, the air-fuel ratio which is caused by a decrease in flow rate via exhaust temperature can also be affected. By knowing the change in the fuel injection amount and reflecting this in the fuel injection amount, it is possible to prevent pre-ignition due to a deviation in the air-fuel ratio when air-fuel ratio is not being fed back.

【0018】[0018]

【発明の効果】空燃比の非フィードバック運転時に排気
温度により空燃比のリーン側への変化を知り、排気温度
に応じて燃料増量を実行することで空燃比のずれを防止
し、プレイグニッションの防止を図ることができる。
[Effect of the invention] During air-fuel ratio non-feedback operation, changes in the air-fuel ratio towards the lean side are detected based on the exhaust temperature, and by increasing the amount of fuel according to the exhaust temperature, deviations in the air-fuel ratio are prevented and pre-ignition is prevented. can be achieved.

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

【図1】図1はこの発明の機能構成を示す概略図である
FIG. 1 is a schematic diagram showing the functional configuration of the present invention.

【図2】図2は実施例の燃料噴射内燃機関の全体概略構
成を示す図である。
FIG. 2 is a diagram showing an overall schematic configuration of a fuel injection internal combustion engine according to an embodiment.

【図3】図3は図2の制御回路が実行する燃料噴射ルー
チンのフローチャートを示す図。
FIG. 3 is a diagram showing a flowchart of a fuel injection routine executed by the control circuit of FIG. 2;

【図4】図4は図2の制御回路が実行するフィードバッ
ク補正係数の制御ルーチンのフローチャートである。
FIG. 4 is a flowchart of a feedback correction coefficient control routine executed by the control circuit of FIG. 2;

【図5】図5は空燃比とプレイグニッション余裕度(イ
) 、排気温度(ロ) との関係を示すグラフである。
FIG. 5 is a graph showing the relationship between the air-fuel ratio, pre-ignition margin (a), and exhaust temperature (b).

【符号の説明】[Explanation of symbols]

10…エンジン本体 12…吸気管 14…エアフローメータ 16…スロットル弁 18…排気管 20…ディストリビュータ 22…点火栓 24…点火コイル 26…インジェクタ 30…制御回路 34,36 …クランク角度センサ 38…空燃比センサ 40…排気温度センサ 10...Engine body 12...Intake pipe 14...Air flow meter 16...Throttle valve 18...Exhaust pipe 20...Distributor 22...Spark plug 24...Ignition coil 26...Injector 30...Control circuit 34, 36...Crank angle sensor 38...Air-fuel ratio sensor 40...Exhaust temperature sensor

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】  内燃機関の負荷及び回転数で決まる基
本燃料供給量を算出する手段と、空燃比のフィードバッ
ク制御を行う運転条件を検出する手段と、空燃比フィー
ドバック条件時に所望の空燃比が得られるように基本燃
料供給量に補正を加える手段と、フィードバック補正さ
れた量の燃料を内燃機関に供給する手段とを具備した内
燃機関の空燃比制御装置において、内燃機関の排気温度
を検出する手段と、空燃比のフィードバック制御を行わ
ない運転時において排気温度が所定値以上のとき燃料供
給手段から内燃機関に供給される燃料量を基本燃料供給
量に対して増量補正する手段とを具備する内燃機関の空
燃比制御装置。
1. Means for calculating a basic fuel supply amount determined by the load and rotational speed of an internal combustion engine, means for detecting operating conditions for performing air-fuel ratio feedback control, and means for detecting a desired air-fuel ratio under air-fuel ratio feedback conditions. In an air-fuel ratio control device for an internal combustion engine, the air-fuel ratio control device includes a means for correcting the basic fuel supply amount so that the amount of fuel supplied is corrected, and a means for supplying the feedback-corrected amount of fuel to the internal combustion engine. and means for increasing the amount of fuel supplied from the fuel supply means to the internal combustion engine with respect to the basic fuel supply amount when the exhaust temperature is above a predetermined value during operation without air-fuel ratio feedback control. Engine air-fuel ratio control device.
JP3105810A 1991-05-10 1991-05-10 Air fuel ratio control device for internal combustion engine Pending JPH04334736A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3105810A JPH04334736A (en) 1991-05-10 1991-05-10 Air fuel ratio control device for internal combustion engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3105810A JPH04334736A (en) 1991-05-10 1991-05-10 Air fuel ratio control device for internal combustion engine

Publications (1)

Publication Number Publication Date
JPH04334736A true JPH04334736A (en) 1992-11-20

Family

ID=14417460

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3105810A Pending JPH04334736A (en) 1991-05-10 1991-05-10 Air fuel ratio control device for internal combustion engine

Country Status (1)

Country Link
JP (1) JPH04334736A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008065936A1 (en) * 2006-11-27 2008-06-05 Toyota Jidosha Kabushiki Kaisha Alcohol-fuel internal combustion engine

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02216320A (en) * 1989-02-14 1990-08-29 Kubota Ltd Safety device for motor-driven working vehicle

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02216320A (en) * 1989-02-14 1990-08-29 Kubota Ltd Safety device for motor-driven working vehicle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008065936A1 (en) * 2006-11-27 2008-06-05 Toyota Jidosha Kabushiki Kaisha Alcohol-fuel internal combustion engine

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