JPH0429856B2 - - Google Patents
Info
- Publication number
- JPH0429856B2 JPH0429856B2 JP57233672A JP23367282A JPH0429856B2 JP H0429856 B2 JPH0429856 B2 JP H0429856B2 JP 57233672 A JP57233672 A JP 57233672A JP 23367282 A JP23367282 A JP 23367282A JP H0429856 B2 JPH0429856 B2 JP H0429856B2
- Authority
- JP
- Japan
- Prior art keywords
- air
- fuel ratio
- engine
- temperature
- sensor
- 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 - Lifetime
Links
- 239000000446 fuel Substances 0.000 claims description 72
- 238000000034 method Methods 0.000 claims description 14
- 238000002485 combustion reaction Methods 0.000 claims description 10
- 238000002347 injection Methods 0.000 description 27
- 239000007924 injection Substances 0.000 description 27
- 238000012937 correction Methods 0.000 description 20
- 239000000498 cooling water Substances 0.000 description 11
- 239000003054 catalyst Substances 0.000 description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 8
- 239000001301 oxygen Substances 0.000 description 8
- 229910052760 oxygen Inorganic materials 0.000 description 8
- 239000007789 gas Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 230000008569 process Effects 0.000 description 4
- 230000003197 catalytic effect Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 239000002828 fuel tank Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000010705 motor oil Substances 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
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1486—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor with correction for particular operating conditions
- F02D41/1488—Inhibiting the regulation
- F02D41/1489—Replacing of the control value by a constant
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
本発明は、車両用内燃機関の空燃比制御方法に
係り、特に、空燃比センサおよび三元触媒を用い
て排気ガス浄化対策が施された自動車用エンジン
に用いるのに好適な、排気空燃比の状態に応じて
空燃比をフイードバツク制御して、空燃比が目標
空燃比となるようにした車両用内燃機関の空燃比
制御方法の改良に関する。
The present invention relates to an air-fuel ratio control method for a vehicle internal combustion engine, and particularly to an exhaust air-fuel ratio control method suitable for use in an automobile engine in which exhaust gas purification measures are taken using an air-fuel ratio sensor and a three-way catalyst. The present invention relates to an improvement in an air-fuel ratio control method for a vehicle internal combustion engine in which the air-fuel ratio is feedback-controlled according to the state so that the air-fuel ratio becomes a target air-fuel ratio.
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−リーン状態を感知
する酸素濃度センサからなる空燃比センサと、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からなる空燃比
制御手段とを備え、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
じて、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、目標空燃比、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。
このような空燃比制御によれば、エンジン運転
状態の変化にかかわらず、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。
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 air-fuel ratio sensor consisting of an oxygen concentration sensor that detects the rich-lean state of the exhaust air-fuel ratio from the oxygen concentration in the exhaust gas, and a fuel an air-fuel ratio control means consisting of an electronically controlled fuel injection device that controls the air-fuel ratio of the air-fuel mixture by controlling the injection amount; Depending on the state, the fuel injection amount of the electronically controlled fuel injection device,
That is, a system in which the air-fuel ratio is feedback-controlled to make the oxygen concentration in the exhaust gas equal to the oxygen concentration when a mixture at a target air-fuel ratio, for example, a stoichiometric air-fuel ratio is combusted, has been put into practical use. There is. Such air-fuel ratio control is characterized in that good exhaust gas purification performance can be obtained regardless of changes in engine operating conditions.
しかしながら従来は、高温条件下で長時間高速
走行をした後、急に車両を停車してアイドル運転
状態で放置した場合や、車両を停車していて、ア
クセルのオンオフを何回も繰返した場合に、空燃
比がリツチ側にずれてしまい、エンジンがラフア
イドル状態となるだけでなく、触媒から刺激臭が
発生することがあるという問題点を有していた。
即ち、第１図Ａに示す如く、例えば大気温40
℃、日射有り、風無し若しくは追い風という高温
条件下で、高温高負荷走行をした後、急に車両を
停車して、アイドル運転状態で放置した場合、高
速走行状態では、走行風もあり、エンジンのサー
モスタットの働きで、エンジン冷却水温が上昇、
下降を繰返しながら、通常状態上限以下の温度に
制御されているが、この場合のような状況下で、
急にアイドル運転状態で放置すると、冷却フアン
は回つていても、走行風が全く無くなるため、エ
ンジン冷却水温は制御不可能となり、第１図Ｂに
示す如く、異常に高くなる。又、エンジンルーム
内の温度が上昇するため、吸気温度が高くなり、
特に、吸入空気量感知式電子制御燃料噴射装置を
備えたエンジンにおいては、空気の密度が低下す
ること、及び、酸素濃度センサの温度が高くなる
ため、制御周波数が高くなり、リツチと判定して
いる時間が短くなることによつて、第１図Ｄに実
線Ａで示す如く、空燃比も急激にリツチ側にすれ
てしまう。従つて、エンジン回転速度も、第１図
Ｃに示す如く、正規のアイドル回転速度よりも低
く且つ不安定となり、いわゆるラフアイドル状態
となる。この時、当然触媒温度も高いため、触媒
で発生するHCによる刺激臭もみられる。
又、車両を停車していて、アクセルのオンオフ
を何回も繰返した場合も、アイドルスイツチがオ
フとなつた時の非同期噴射が何回も行われるた
め、空燃比がリツチ−リーンを繰返しながらリツ
チ側にずれ、且つ、エンジン冷却水温及び触媒温
度も異常に上昇してゆき、その後、アイドル状態
に戻しても、空燃比はリツチずれして、ラフアイ
ドルとなつたり、刺激臭が発生することがあつ
た。
本発明は、前記従来の問題点を解消するべくな
されたもので、高温条件下で長時間高速走行した
後に急に車両を停車してアイドル放置した場合
や、車両を停車していてアクセルのオンオフを何
回も繰返した場合の、ラフアイドルや触媒刺激臭
の発生を防止することができる車両用内燃機関の
空燃比制御方法を提供することを目的とする。
However, conventionally, after driving at high speed for a long time under high temperature conditions, the vehicle suddenly stops and is left idling, or when the vehicle is stopped and the accelerator is repeatedly turned on and off. However, the air-fuel ratio deviates to the rich side, which not only causes the engine to idle roughly, but also causes the catalyst to emit a pungent odor. That is, as shown in Figure 1A, for example, when the atmospheric temperature is 40
℃, with sunlight, no wind, or a tailwind, and after driving at high temperature and high load, suddenly stop the vehicle and leave it idling, when driving at high speed, there is wind, and the engine The engine cooling water temperature rises due to the action of the thermostat.
While repeatedly falling, the temperature is controlled to below the upper limit of the normal state, but under conditions like this case,
If the engine is suddenly left in an idling state, the engine cooling water temperature becomes uncontrollable and becomes abnormally high, as shown in FIG. 1B, because there is no running air even though the cooling fan is rotating. Also, as the temperature in the engine room increases, the intake air temperature increases,
In particular, in engines equipped with an electronically controlled fuel injection system that senses the amount of intake air, the density of the air decreases and the temperature of the oxygen concentration sensor increases, so the control frequency increases and the fuel is determined to be rich. As the time spent in the fuel tank becomes shorter, the air-fuel ratio also rapidly shifts to the rich side, as shown by the solid line A in FIG. 1D. Therefore, as shown in FIG. 1C, the engine rotational speed is lower than the normal idle rotational speed and becomes unstable, resulting in a so-called rough idle state. At this time, the catalyst temperature is naturally high, so an irritating odor from HC generated by the catalyst can also be seen. Also, if the vehicle is stopped and the accelerator is turned on and off many times, the asynchronous injection will occur many times when the idle switch is turned off, so the air-fuel ratio will repeatedly go from rich to lean. In addition, the engine cooling water temperature and catalyst temperature also rise abnormally, and even after returning to the idle state, the air-fuel ratio shifts by a bit, resulting in a rough idle and an irritating odor. It was hot. The present invention has been made to solve the above-mentioned problems of the conventional technology, and is applicable when the vehicle is stopped suddenly after driving at high speed for a long time under high temperature conditions and left idling, or when the vehicle is stopped and the accelerator is turned on or off. An object of the present invention is to provide an air-fuel ratio control method for a vehicle internal combustion engine that can prevent rough idle and catalyst irritating odor from occurring when the above steps are repeated many times.
本発明は、排気空燃比の状態に応じて空燃比を
フイードバツク制御して、空燃比が目標空燃比と
なるようにした車両用内燃機関の空燃比制御方法
において、第２図にその要旨を示す如く、車速が
所定値以下の状態にあり、且つ、エンジン温度が
通常走行時では取り得ない上限温度以上である時
には、前記フイードバツク制御を停止し、且つ、
空燃比をリーン補正して、空燃比をリーン化する
と共に、車速が前記所定値以上、又は、エンジン
温度が前記上限温度以下のときには、前記フイー
ドバツク制御を再開するようにして、前記目的を
達成したものである。
The present invention is an air-fuel ratio control method for a vehicle internal combustion engine, in which the air-fuel ratio is feedback-controlled according to the state of the exhaust air-fuel ratio so that the air-fuel ratio becomes a target air-fuel ratio, the gist of which is shown in FIG. Thus, when the vehicle speed is below a predetermined value and the engine temperature is above an upper limit temperature that cannot be achieved during normal driving, the feedback control is stopped, and
The purpose is achieved by correcting the air-fuel ratio lean to make the air-fuel ratio lean, and restarting the feedback control when the vehicle speed is above the predetermined value or when the engine temperature is below the upper limit temperature. It is something.
以下、図面を参照して、本発明に係る車両用内
燃機関の空燃比制御方法が採用された自動車用エ
ンジンの吸入空気量感知式電子制御燃料噴射装置
の実施例を詳細に説明する。
本実施例は、第３図に示すごとく、大気を取り
入れるためのエアクリーナ１２と、該エアクリー
ナ１２により吸気管１３に取り入れられた吸入空
気の流量を検出するためのエアフローメータ１４
と、該エアフローメータ１４に内蔵された、吸入
空気の温度を検出するための吸気温センサ１６
と、スロツトルボデイ１８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２０と、該スロツトル弁
２０が全開状態にある時にオンとなるアイドルス
イツチを含むスロツトルセンサ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燃料を噴射するためのイン
ジエクタ２６と、排気マニホルド２８に配設され
た、排気ガス中の酸素濃度から空燃比を検知する
ための酸素濃度センサ（以下O2センサと称する）
３０と、排気管３２の途中に配設された三元触媒
コンバータ３４と、エンジン１０のシリンダブロ
ツクに配設された、エンジン冷却水温を検知する
ための水温センサ３６と、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（図示省略）を有し、エンジン回転に応じて所
定クランク角度に点火１次信号Igを発生すると共
に、該点火１次信号Igに応じて点火コイル３８で
発生された高圧の点火２次信号を各気筒の点火プ
ラグ３９に配電するためのデストリビユータ４０
と、変速機４２の出力軸の回転速度から、エンジ
ン１０が搭載された自動車の走行速度を検知する
ための車速センサ４４と、バツテリ４６と、前記
エアフローメータ１４出力の吸入空気量と前記点
火１次信号1gから求められるエンジン回転速度
に応じて、所定クランク角毎に基本噴射時間に対
応するパルス幅の基本噴射パルス信号Tpを発生
すると共に、該基本噴射パルス信号Tpに各種補
正を加えて前記インジエクタ２６にインジエクタ
駆動パルス信号Tiを出力するアナログ演算回路、
及び、該アナログ演算回路から出力される基本噴
射パルス信号Tpに、前記O2センサ３０の出力の
空燃比のリツチ−リーン状態に応じたフイードバ
ツク補正、前記スロツトルセンサ２２の出力に応
じた補正等を加えるための補正信号Vfを形成す
ると共に、エンジン運転状態が所定運転状態とな
つた時、例えば、前記スロツトルセンサ２２のア
イドルスイツチがオフとなつた時は、即座に非同
期噴射パルス信号Taを発生するデジタル演算回
路を含むハイブリツド型のエンジン制御装置４８
とを備えた自動車用４気筒エンジン１０の吸入空
気量感知式電子制御燃料噴射装置において、前記
エンジン制御装置４８内で、車速が所定値以下の
状態にあり、且つ、エンジン温度が通常走行時で
は取り得ない上限温度以上であるときは、前記フ
イードバツク補正を停止し、且つ、空燃比補正係
数を一律に５〜10％程度、例えば５％減少させ
て、空燃比をリーン化すると共に、車速が前記所
定値以上、又は、エンジン温度が前記上限温度以
下のときには、前記フイードバツク制御を再開す
るようにしたものである。
前記エンジン制御装置４８は、第４図に詳細に
示すごとく、前記デストリビユータ４０から入力
される点火１次信号Igを分周して所定クランク角
毎の信号とするための分周回路５０と、該分周回
路５０出力および前記エアフローメータ１４から
入力される吸入空気量信号に応じて、基本噴射時
間に対応するパルス幅の基本噴射パルス信号Tp
を所定クランク角毎に発生する基本噴射パルス生
成回路５２と、ダイオード５４を介して入力され
る基本噴射パルス信号Tpに対して、前記吸気温
センサ１６出力の吸気温信号、前記水温センサ３
６出力のエンジン冷却水温信号および後出デジタ
ル制御回路出力の補正信号Vfに応じて補正を施
すための乗算補正回路５６と、該乗算補正回路５
６の出力のインジエクタ駆動パルス信号Tiと後
出デジタル制御回路出力の非同期噴射パルス信号
Taとの論理和を出力するOR回路５８と、該OR
回路５８出力によつて駆動され、前記インジエク
タ２６に通電するためのインジエクタ駆動トラン
ジスタ６０と、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装置（以
下CPUと称する）６２ａ、各種時間信号を発生
するためのタイマ６２ｂ、前記基本噴射パルス生
成回路５２出力の基本噴射パルス信号Tpに応じ
て割込みを行うための割込み制御部６２ｃ、前記
O2センサ３０出力の空燃比信号、前記スロツト
ルセンサ２２の出力、前記車速センサ４４の出力
等を取り込むためのデシタル入力ポート６２ｄ、
前記エアフローメータ１４から入力される吸入空
気量信号、前記水温センサ３６から入力されるエ
ンジン冷却水温信号等をデジタル信号に変換して
取り込むためのアナログ−デジタルコンバータ
（以下Ａ／Ｄコンバータと称する）６２ｅ、CPU
６２ａ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）６２ｆ、制御プログラムや各種定数等を記
憶するためのリードオンリーメモリ（以下ROM
と称する）６２ｇ、前記CPU６２ａにおける演
算結果に応じて、非同期噴射パルス信号Taを前
記OR回路５８に出力するためのデジタル出力ポ
ート６２ｈ、同じく前記CPU６２ａにおける演
算結果に応じて得られるデジタル補正信号をアナ
ログ補正信号Vfに変換して前記乗算補正回路５
６に出力するためのデジタル−アナログコンバー
タ（以下Ｄ／Ａコンバータと称する）６２ｉ、キ
イスイツチ４９を介して印加される前記バツテリ
４６の電圧を各構成機器に供給するための電源回
路６２ｊ、および前記バツテリ４６から直接印加
される電圧を前記RAM６２ｆに供給するための
電源回路６２ｋからなるデジタル制御回路６２と
から構成されている。第３図において、６４は、
プルアツプ抵抗、６６は、インジエクタ用レジス
タである。
以下作用を説明する。
本実施例における空燃比のリーン補正は、第５
図に示すようなルーチンに従つて実行される。即
ち、まず、ステツプ101で、前記車速センサ４４
の出力に応じて、車速が所定値、例えば７Km／ｈ
以下であるか否かを判定する。判定結果が正であ
る場合、は、ステツプ102に進み、前記水温セン
サ３６の出力に応じて、エンジン冷却水温が、通
常状態上限よりも高い所定値以上であるか否かを
判定する。判定結果が正である場合、即ち、エン
ジン冷却水温が通常以上に高いと判断される時に
は、ステツプ103に進み、前記O2センサ３０の出
力による空燃比フイードバツク補正を停止する。
次いでステツプ104に進み、空燃比補正係数を、
例えば、一律に５％減少して、燃料噴射時間が一
律に減らされるようにし、空燃比がリーン化され
るようにして、このルーチンを終了する。
一方、前出ステツプ101又は102の判定結果が否
である場合、即ち、通常運転状態にあると判断さ
れる時には、ステツプ105に進み、前記O2センサ
３０の出力にもとづいて空燃比補正係数を求め、
フイードバツク補正が行われるようにして、この
ルーチンを終了する。
本実施例における、高温条件下で高速高荷走行
をした後にアイドル放置した場合の空燃比及び空
燃比補正係数の変化状態を、前出第１図Ｄ，Ｅ中
に破線Ｂで示す。
本実施例によれば、空燃比のリツチずれが防止
され、従つて、ラフアイドルや触媒刺激臭の発生
が防止される。
前記実施例においては、エンジン冷却水温から
エンジン温度を検知するようにしていたが、エン
ジン温度を検知する方法はこれに限定されず、例
えばエンジン油温からエンジン温度を検知するよ
うに構成することも可能である。
なお、先に述べたように、停車中に何回もアク
セルオンオフを繰返した場合も、同様な状態とな
るため、本発明により対処できる。
前記実施例においては、本発明が、ハイブリツ
ド型のエンジン制御装置を備えた吸入空気量感知
式電子制御燃料噴射装置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、完全にデジ
タル化されたデジタル型エンジン制御装置を備え
た吸入空気量感知式電子制御燃料噴射エンジン、
あるいは、吸気管圧力感知式電子制御燃料噴射エ
ンジン、更には、一般の内燃機関にも同様に適用
できることは明らかである。
DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an electronically controlled fuel injection system that senses the amount of intake air for an automobile engine will be described in detail with reference to the drawings, in which the air-fuel ratio control method for an internal combustion engine for a vehicle according to the present invention is adopted. As shown in FIG. 3, this embodiment includes an air cleaner 12 for taking in atmospheric air, and an air flow meter 14 for detecting the flow rate of intake air taken into an intake pipe 13 by the air cleaner 12.
and an intake temperature sensor 16 built into the air flow meter 14 for detecting the temperature of intake air.
, a throttle valve 20 for controlling the flow rate of intake air, which is disposed on the throttle body 18 and is opened and closed in conjunction with an accelerator pedal (not shown) disposed on the driver's seat; and the throttle valve 20 . a throttle sensor 22 including an idle switch that is turned on when the engine 20 is fully open; an injector 26 disposed in the intake manifold 24 for injecting fuel toward the intake port of each cylinder of the engine 10; An oxygen concentration sensor (hereinafter referred to as an O 2 sensor) disposed in the exhaust manifold 28 for detecting the air-fuel ratio from the oxygen concentration in the exhaust gas.
30, a three-way catalytic converter 34 disposed in the middle of the exhaust pipe 32, a water temperature sensor 36 disposed in the cylinder block of the engine 10 for detecting the engine cooling water temperature, and a three-way catalytic converter 34 disposed in the middle of the exhaust pipe 32; It has a distributor shaft (not shown) that rotates in conjunction with the rotation of the engine, and generates a primary ignition signal Ig at a predetermined crank angle according to the rotation of the engine, and generates it in the ignition coil 38 in response to the primary ignition signal Ig. a distributor 40 for distributing the generated high-voltage secondary ignition signal to the spark plugs 39 of each cylinder;
, a vehicle speed sensor 44 for detecting the running speed of the vehicle in which the engine 10 is mounted from the rotational speed of the output shaft of the transmission 42, a battery 46, the amount of intake air output from the air flow meter 14, and the ignition 1. In accordance with the engine speed determined from the next signal 1g, a basic injection pulse signal Tp with a pulse width corresponding to the basic injection time is generated at every predetermined crank angle, and various corrections are made to the basic injection pulse signal Tp to generate the basic injection pulse signal Tp. an analog calculation circuit that outputs an injector drive pulse signal Ti to the injector 26;
The basic injection pulse signal Tp output from the analog calculation circuit is subjected to feedback correction according to the rich-lean state of the air-fuel ratio output from the O 2 sensor 30, correction according to the output from the throttle sensor 22, etc. In addition, when the engine operating state reaches a predetermined operating state, for example, when the idle switch of the throttle sensor 22 is turned off, the asynchronous injection pulse signal Ta is immediately generated. A hybrid engine control device 48 including a digital arithmetic circuit that generates
In the intake air amount sensing type electronically controlled fuel injection system for a four-cylinder automobile engine 10, the engine control device 48 determines that when the vehicle speed is below a predetermined value and the engine temperature is during normal running, When the temperature is higher than the upper limit temperature that cannot be achieved, the feedback correction is stopped, and the air-fuel ratio correction coefficient is uniformly reduced by about 5 to 10%, for example, 5%, to make the air-fuel ratio leaner and to reduce the vehicle speed to the above level. When the engine temperature is above a predetermined value or below the upper limit temperature, the feedback control is restarted. As shown in detail in FIG. 4, the engine control device 48 includes a frequency dividing circuit 50 for dividing the frequency of the primary ignition signal Ig inputted from the distributor 40 into a signal for each predetermined crank angle; A basic injection pulse signal Tp with a pulse width corresponding to the basic injection time is determined according to the output of the frequency dividing circuit 50 and the intake air amount signal input from the air flow meter 14.
A basic injection pulse generation circuit 52 that generates the same at every predetermined crank angle and a basic injection pulse signal Tp inputted through a diode 54 generates an intake air temperature signal output from the intake air temperature sensor 16 and the water temperature sensor 3.
a multiplication correction circuit 56 for performing correction according to the engine cooling water temperature signal of 6 outputs and the correction signal Vf of the digital control circuit output shown later; and the multiplication correction circuit 5
Injector drive pulse signal Ti of output 6 and asynchronous injection pulse signal of digital control circuit output later
An OR circuit 58 that outputs the logical sum with Ta, and the OR circuit 58 that outputs the logical sum with Ta.
An injector drive transistor 60 driven by the output of the circuit 58 to energize the injector 26, a central processing unit (hereinafter referred to as CPU) 62a consisting of, for example, a microprocessor for performing various arithmetic operations, and various time periods. a timer 62b for generating a signal; an interrupt control section 62c for making an interrupt in response to the basic injection pulse signal Tp output from the basic injection pulse generation circuit 52;
a digital input port 62d for receiving the air-fuel ratio signal output from the O 2 sensor 30, the output from the throttle sensor 22, the output from the vehicle speed sensor 44, etc.;
An analog-to-digital converter (hereinafter referred to as A/D converter) 62e for converting the intake air amount signal input from the air flow meter 14, the engine cooling water temperature signal input from the water temperature sensor 36, etc. into digital signals and importing them. ,CPU
Random access memory (hereinafter referred to as RAM) 62f for temporarily storing calculation data etc. in 62a, read-only memory (hereinafter referred to as ROM) for storing control programs and various constants, etc.
) 62g, a digital output port 62h for outputting the asynchronous injection pulse signal Ta to the OR circuit 58 in accordance with the calculation result in the CPU 62a, and a digital correction signal obtained in accordance with the calculation result in the CPU 62a as an analog output port 62h; The multiplication correction circuit 5 converts it into a correction signal Vf.
6, a power supply circuit 62j for supplying the voltage of the battery 46 applied via the key switch 49 to each component; 46, and a digital control circuit 62 consisting of a power supply circuit 62k for supplying the voltage directly applied from 46 to the RAM 62f. In FIG. 3, 64 is
A pull-up resistor 66 is an injector resistor. The action will be explained below. The lean correction of the air-fuel ratio in this embodiment is performed by the fifth
It is executed according to the routine shown in the figure. That is, first, in step 101, the vehicle speed sensor 44 is
Depending on the output of
Determine whether the following is true. If the determination result is positive, the process proceeds to step 102, and it is determined in accordance with the output of the water temperature sensor 36 whether the engine cooling water temperature is equal to or higher than a predetermined value higher than the upper limit of the normal state. If the determination result is positive, that is, if it is determined that the engine cooling water temperature is higher than normal, the process proceeds to step 103, and the air-fuel ratio feedback correction based on the output of the O 2 sensor 30 is stopped.
Next, the process proceeds to step 104, where the air-fuel ratio correction coefficient is
For example, the fuel injection time is uniformly reduced by 5%, the air-fuel ratio is made lean, and this routine ends. On the other hand, if the judgment result in step 101 or 102 is negative, that is, if it is judged that the engine is in a normal operating state, the process proceeds to step 105, and the air-fuel ratio correction coefficient is calculated based on the output of the O 2 sensor 30. seek,
This routine ends after feedback correction is performed. In this embodiment, the state of change in the air-fuel ratio and the air-fuel ratio correction coefficient when the vehicle is left idling after running at high speed and with a heavy load under high-temperature conditions is shown by the broken line B in FIGS. 1D and E above. According to this embodiment, a rich shift in the air-fuel ratio is prevented, and therefore, rough idle and catalyst irritating odor are prevented from occurring. In the embodiment described above, the engine temperature is detected from the engine cooling water temperature, but the method for detecting the engine temperature is not limited to this. For example, the engine temperature may be detected from the engine oil temperature. It is possible. As mentioned above, even if the accelerator is turned on and off many times while the vehicle is stopped, a similar situation will occur, which can be dealt with by the present invention. In the above embodiment, the present invention was applied to an intake air amount sensing type electronically controlled fuel injection device equipped with a hybrid type engine control device, but the scope of application of the present invention is not limited to this, and is not completely limited to this. Intake air amount sensing electronically controlled fuel injection engine equipped with a digital engine control device.
Alternatively, it is clear that the present invention can be similarly applied to intake pipe pressure sensing type electronically controlled fuel injection engines, and furthermore, to general internal combustion engines.
以上説明した通り、本発明によれば、高温条件
下で高速高負荷走行した後にアイドル放置した場
合や、停車中にアクセルオンオフを何回も繰返し
た場合の空燃比のリツチずれが防止でき、従つ
て、ラフアイドルや触媒刺激臭の発生が防止でき
る。又、実用上の燃費性能も向上することができ
る等の優れた効果を有する。
As explained above, according to the present invention, it is possible to prevent the air-fuel ratio from becoming richer when left idling after driving at high speed and under high load under high temperature conditions, or when the accelerator is repeatedly turned on and off while stopped. As a result, rough idle and catalyst irritating odor can be prevented. Moreover, it has excellent effects such as being able to improve practical fuel efficiency.
第１図は、従来例及び本発明の実施例におけ
る、高温条件下で高速高負荷走行をした後にアイ
ドル放置した時の、車速、エンジン冷却水温、エ
ンジン回転速度、空燃比及び空燃比補正係数の関
係の例を比較して示す線図、第２図は、本発明に
係る車両用内燃機関の空燃比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、自動
車用エンジンの吸入空気量感知式電子制御燃料噴
射装置の実施例の構成を示す、一部断面図を含む
平面図、第４図は、前記実施例で用いられている
エンジン制御装置の構成を示すブロツク線図、第
５図は、同じく、車速及びエンジン冷却水温に応
じて空燃比のリーン補正を行うためのルーチンの
要部を示す流れ図である。
１０……エンジン、２０……スロツトル弁、２
２……ストツトルセンサ、２６……インジエク
タ、３０……酸素濃度センサ（O2センサ）、３４
……三元触媒コンバータ、３６……水温センサ、
４０……デストリビユータ、４２……変速機、４
４……車速センサ、４８……エンジン制御装置。
Figure 1 shows the vehicle speed, engine cooling water temperature, engine rotational speed, air-fuel ratio, and air-fuel ratio correction coefficient when left idling after driving at high speed and under high load under high temperature conditions in a conventional example and an embodiment of the present invention. FIG. 2 is a flowchart showing the gist of the air-fuel ratio control method for a vehicle internal combustion engine according to the present invention, and FIG. 3 is a diagram showing a comparison of examples of relationships. FIG. FIG. 4 is a plan view including a partial sectional view showing the configuration of an embodiment of the intake air amount sensing electronically controlled fuel injection device; FIG. 4 is a block line diagram showing the structure of the engine control device used in the embodiment; Similarly, FIG. 5 is a flowchart showing a main part of a routine for performing lean correction of the air-fuel ratio according to vehicle speed and engine cooling water temperature. 10...Engine, 20...Throttle valve, 2
2...Stottle sensor, 26...Injector, 30...Oxygen concentration sensor (O 2 sensor), 34
...Three-way catalytic converter, 36...Water temperature sensor,
40...distributor, 42...transmission, 4
4... Vehicle speed sensor, 48... Engine control device.
Claims (1)
バツク制御して、空燃比が目標空燃比となるよう
にした車両用内燃機関の空燃比制御方法におい
て、 車速が所定値以下の状態にあり、且つ、エンジ
ン温度が通常走行時では取り得ない上限温度以上
である時は、前記フイードバツク制御を停止し、
且つ、空燃比をリーン補正して、空燃比をリーン
化すると共に、 車速が前記所定値以上、又は、エンジン温度が
前記上限温度以下のときには、前記フイードバツ
ク制御を再開することを特徴とする車両用内燃機
関の空燃比制御方法。[Scope of Claims] 1. An air-fuel ratio control method for a vehicle internal combustion engine in which the air-fuel ratio is feedback-controlled according to the state of the exhaust air-fuel ratio so that the air-fuel ratio becomes a target air-fuel ratio, comprising: , and when the engine temperature is higher than the upper limit temperature that cannot be achieved during normal driving, the feedback control is stopped;
Further, the air-fuel ratio is lean-corrected to make the air-fuel ratio lean, and when the vehicle speed is above the predetermined value or the engine temperature is below the upper limit temperature, the feedback control is restarted. Air-fuel ratio control method for internal combustion engines.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23367282A JPS59126048A (en) | 1982-12-29 | 1982-12-29 | Air-fuel ratio controlling method for internal- combustion engine for vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23367282A JPS59126048A (en) | 1982-12-29 | 1982-12-29 | Air-fuel ratio controlling method for internal- combustion engine for vehicle |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59126048A JPS59126048A (en) | 1984-07-20 |
| JPH0429856B2 true JPH0429856B2 (en) | 1992-05-20 |
Family
ID=16958717
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23367282A Granted JPS59126048A (en) | 1982-12-29 | 1982-12-29 | Air-fuel ratio controlling method for internal- combustion engine for vehicle |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59126048A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01136667U (en) * | 1988-03-14 | 1989-09-19 |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5629154A (en) * | 1979-08-20 | 1981-03-23 | Nissan Motor Co Ltd | Control unit for air fuel ratio |
-
1982
- 1982-12-29 JP JP23367282A patent/JPS59126048A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5629154A (en) * | 1979-08-20 | 1981-03-23 | Nissan Motor Co Ltd | Control unit for air fuel ratio |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59126048A (en) | 1984-07-20 |
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