JPH05163984A - Device for detecting trouble of air-fuel ratio detecting device - Google Patents
Device for detecting trouble of air-fuel ratio detecting deviceInfo
- Publication number
- JPH05163984A JPH05163984A JP3330421A JP33042191A JPH05163984A JP H05163984 A JPH05163984 A JP H05163984A JP 3330421 A JP3330421 A JP 3330421A JP 33042191 A JP33042191 A JP 33042191A JP H05163984 A JPH05163984 A JP H05163984A
- Authority
- JP
- Japan
- Prior art keywords
- air
- fuel ratio
- sensor
- catalyst
- ratio 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.)
- Granted
Links
Classifications
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- Y02T10/47—
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明はエンジンの空燃比を目標
空燃比にフィードバック制御するための空燃比検出装置
の故障検出に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to detection of a failure in an air-fuel ratio detection device for feedback-controlling an air-fuel ratio of an engine to a target air-fuel ratio.
【０００２】[0002]
【従来の技術】エンジンの空燃比制御では、例えば燃料
噴射量による空燃比制御の場合、エンジンの吸入空気量
およびエンジン回転数に応じた基本噴射量を演算し、こ
の基本噴射量をエンジン水温等に応じて補正し、また、
排気ガス中の酸素濃度を検出するＯ2センサ等の検出信
号に基づいてフィードバック補正を行い、最終噴射量を
設定する。そして、この最終噴射量に応じた噴射パルス
によってインジェクタを駆動し空燃比を目標空燃比に収
束させる。このような空燃比フィードバック制御によれ
ば、エンジンの空燃比を例えば理論空燃比に制御するこ
とができるため、排気通路に三元触媒等を配設して排気
ガス浄化を効率良く行うことが可能となる。ここで、空
燃比センサは一般に触媒の上流側に設けられる。2. Description of the Related Art In air-fuel ratio control of an engine, for example, in the case of air-fuel ratio control based on a fuel injection amount, a basic injection amount is calculated according to an intake air amount of the engine and an engine speed, and this basic injection amount is used as an engine water temperature or the like. According to
Feedback correction is performed based on a detection signal from an O 2 sensor or the like that detects the oxygen concentration in the exhaust gas, and the final injection amount is set. Then, the injector is driven by the injection pulse corresponding to the final injection amount to converge the air-fuel ratio to the target air-fuel ratio. According to such air-fuel ratio feedback control, the air-fuel ratio of the engine can be controlled to, for example, the theoretical air-fuel ratio, so that a three-way catalyst or the like can be arranged in the exhaust passage to efficiently perform exhaust gas purification. Becomes Here, the air-fuel ratio sensor is generally provided on the upstream side of the catalyst.
【０００３】上記のようにエンジンの排気通路に触媒を
配設し、空燃比を例えば理論空燃比に制御するようフィ
ードバック制御系を構成する場合に、空燃比センサの出
力特性のばらつきとか経時的な劣化を補償するため、触
媒の下流側に第２の空燃比センサを設けて、上流側の空
燃比センサの出力がリッチ信号からリーン信号に、また
リーン信号からリーン信号に変化した時の遅延処理の設
定時間をこの下流側空燃比センサの出力に応じて補正す
るダブルＯ2センサシステムとすることが従来から提案
されている。また、例えば特開昭６１−２３４２４１号
公報に記載のものでは、このようにダブルＯ2センサシ
ステムとしたものにおいて、上流側空燃比センサの劣化
による応答性の低下（制御周波数の低下）を最小限にす
るため、上流側空燃比センサによる空燃比制御のスキッ
プ値（Ｐ値）を下流側空燃比センサの出力によりフィー
ドバック補正するようにした所謂Ｐ値フィードバック制
御を行っている。この場合、下流側空燃比センサの出力
特性の変化は上流側空燃比センサの劣化度合を反映する
ものであり、したがって、下流側空燃比センサの出力に
よって上流側空燃比センサの故障（劣化）検出が行え
る。When the catalyst is arranged in the exhaust passage of the engine as described above and the feedback control system is configured to control the air-fuel ratio to, for example, the stoichiometric air-fuel ratio, there are variations in the output characteristics of the air-fuel ratio sensor and time-dependent changes. In order to compensate for the deterioration, a second air-fuel ratio sensor is provided on the downstream side of the catalyst, and delay processing is performed when the output of the upstream air-fuel ratio sensor changes from a rich signal to a lean signal or from a lean signal to a lean signal. It has been conventionally proposed to use a double O 2 sensor system that corrects the set time according to the output of the downstream side air-fuel ratio sensor. Further, for example, in the one disclosed in Japanese Patent Application Laid-Open No. 61-234241, in such a double O 2 sensor system, the deterioration of the responsiveness (the decrease of the control frequency) due to the deterioration of the upstream side air-fuel ratio sensor is minimized. In order to limit the limit, so-called P-value feedback control is performed in which the skip value (P value) of the air-fuel ratio control by the upstream side air-fuel ratio sensor is feedback-corrected by the output of the downstream side air-fuel ratio sensor. In this case, the change in the output characteristic of the downstream side air-fuel ratio sensor reflects the degree of deterioration of the upstream side air-fuel ratio sensor, and therefore the failure (deterioration) of the upstream side air-fuel ratio sensor is detected by the output of the downstream side air-fuel ratio sensor. Can be done.
【０００４】ところで、触媒の上流側に配設されたＯ2
センサ等空燃比センサの劣化の形態には、制御中心がリ
ーン側にずれるリーンシフト劣化と、制御中心が逆にリ
ッチ側にずれるリッチシフト劣化と、応答性の悪化によ
り出力波形の反転回数すなわち周波数が小さくなる周波
数劣化の三通りあることが知られている。このうち、リ
ーンシフト劣化およびリッチシフト劣化は、Ｐ値フィー
ドバック制御により設定された空燃比フィードバック制
御のスキップ値（Ｐ値）が異常レベル（しきい値）に達
したかどうかで検出される。一方、周波数劣化は、上流
側空燃比センサの周波数と下流側空燃比センサの周波数
との比が大きくなることにより検出される。By the way, O 2 which is disposed upstream of the catalyst
Deterioration of air-fuel ratio sensors such as sensors includes lean shift deterioration in which the control center shifts to the lean side, rich shift deterioration in which the control center shifts to the rich side conversely, and the number of times the output waveform is inverted, that is, frequency It is known that there are three types of frequency degradation that reduce Among these, the lean shift deterioration and the rich shift deterioration are detected by whether or not the skip value (P value) of the air-fuel ratio feedback control set by the P value feedback control has reached an abnormal level (threshold value). On the other hand, the frequency deterioration is detected when the ratio between the frequency of the upstream air-fuel ratio sensor and the frequency of the downstream air-fuel ratio sensor increases.
【０００５】上記ダブルＯ2センサシステムにおけるＰ
値フィードバック制御は触媒の劣化検出にも利用され
る。この場合、上流側および下流側の空燃比センサの周
波数比を検出値として、検出特性に基づいて劣化状態
（浄化率）を判定し、また、所定のＭ.Ｆ(マルファンク
ション）レベルによって異常状態を判定する。P in the above double O 2 sensor system
The value feedback control is also used for detecting deterioration of the catalyst. In this case, the deterioration ratio (purification rate) is determined based on the detection characteristics, using the frequency ratio of the upstream-side and downstream-side air-fuel ratio sensors as the detection value, and the abnormal state is determined by the predetermined MF (malfunction) level. To judge.
【０００６】[0006]
【発明が解決しようとする課題】空燃比フィードバック
制御のため触媒の上流側に配設したＯ2センサ等空燃比
センサの周波数劣化を検出するのに、上記のようにダブ
ルＯ2センサシステムにおける両センサの周波数の比を
見るようにした場合、空燃比センサの応答性が悪くなり
リッチおよびリーンの判定時間が長くなると、ついには
空燃比の振れが大きくなって触媒のウインドウを大巾に
外れ、触媒のＯ2ストレージ効果が得られなくなって、
下流側センサの出力は触媒が劣化した場合と同じような
波形を示すようになる。そのため、上記従来の方法で
は、触媒が劣化している場合に空燃比センサは正常であ
るにも拘わらず故障と判定してしまうことになるといっ
た問題があった。In order to detect the frequency deterioration of an air-fuel ratio sensor such as an O 2 sensor arranged upstream of the catalyst for air-fuel ratio feedback control, the double O 2 sensor system as described above is used. When looking at the frequency ratio of the sensor, if the responsiveness of the air-fuel ratio sensor deteriorates and the determination time of rich and lean becomes long, finally the fluctuation of the air-fuel ratio becomes large and the catalyst window greatly deviates, The O 2 storage effect of the catalyst can no longer be obtained,
The output of the downstream sensor shows a waveform similar to that when the catalyst deteriorates. Therefore, the above-mentioned conventional method has a problem that when the catalyst is deteriorated, the air-fuel ratio sensor is determined to be defective even though it is normal.
【０００７】また、ダブルＯ2センサシステムで上記の
ようにＰ値フィードバック制御を行うものにおいては、
上流側の空燃比センサの劣化により空燃比が触媒のウイ
ンドウから外れると、そのずれの方向を下流側センサの
出力信号により検出してＰ値を補正するが、Ｐ値のセン
タ（平均値）が収束して空燃比センサの劣化が吸収され
るまでにはある程度時間がかかるため、この間に触媒の
劣化検出を行うと、空燃比センサの劣化が吸収されない
状態で劣化検出が行われ、誤判定を生ずるといった問題
もあった。Further, in the double O 2 sensor system which performs the P value feedback control as described above,
When the air-fuel ratio deviates from the catalyst window due to deterioration of the upstream air-fuel ratio sensor, the deviation direction is detected by the output signal of the downstream sensor to correct the P value, but the center of the P value (average value) is It takes some time to converge and absorb the deterioration of the air-fuel ratio sensor.Therefore, if catalyst deterioration is detected during this period, deterioration detection will be performed without deterioration of the air-fuel ratio sensor being detected, resulting in an erroneous determination. There was a problem that it would occur.
【０００８】本発明は上記問題点に鑑みてなされたもの
であって、第１に、エンジンの空燃比フィードバック制
御のために触媒上流側に配設した第１空燃比センサの劣
化検出を触媒下流側に配設した第２空燃比センサの出力
を用いて行うものにおいて、触媒の劣化と空燃比センサ
の劣化の混同を防止し、第１空燃比センサの劣化を正確
に検出できるようにすることを目的とする。The present invention has been made in view of the above problems. First, deterioration detection of a first air-fuel ratio sensor disposed upstream of the catalyst for air-fuel ratio feedback control of an engine is performed by detecting the deterioration of the catalyst downstream. In order to perform the detection using the output of the second air-fuel ratio sensor disposed on the side, it is possible to prevent confusion between the deterioration of the catalyst and the deterioration of the air-fuel ratio sensor and to accurately detect the deterioration of the first air-fuel ratio sensor. With the goal.
【０００９】また、本発明は、第２に、上記と同様第１
空燃比センサの劣化検出を第２空燃比センサの出力を用
いて行うものにおいて、触媒の劣化検出を正確に行える
ようにすることを目的とする。The present invention is, secondly, the same as the above.
An object of the present invention is to accurately detect deterioration of a catalyst in a case where deterioration of an air-fuel ratio sensor is detected using an output of a second air-fuel ratio sensor.
【００１０】[0010]
【課題を解決するための手段】この出願の第１の発明は
上記第１の目的を達成するための空燃比検出装置の故障
検出装置に係るものであり、図１（ａ）はその全体構成
図である。この発明は、触媒上流側の空燃比センサ（第
１空燃比センサ）が劣化して応答性が悪くなるに伴い、
空燃比の振れが大きくなるために触媒下流側の空燃比セ
ンサ（第２空燃比センサ）の出力波形の周波数が小さく
なるが、そのような現象は特にオフアイドル（有負荷）
時に顕著となるものであって、アイドル時のように吸入
空気量の少ない領域では、もともと空燃比変動の周期が
長いために第１空燃比センサの応答性劣化による影響が
小さく、一方、触媒が劣化した場合は、アイドル，オフ
アイドルにかかわらずＯ2ストレージ効果が得られなく
なるので、上記のように第２空燃比センサの周波数が小
さくなる現象はアイドル時でも現れることに着目し、ア
イドル時に空燃比センサの劣化検出を行うようにすれば
触媒の劣化に伴う誤判定が防止できるという知見を得た
ことによるものであり、その構成は、エンジンの排気通
路において排気ガス浄化のための触媒の上流側に配設さ
れ、エンジンに供給される混合気の空燃比を目標空燃比
にフィードバック制御するため空燃比制御手段に空燃比
信号を出力する第１空燃比センサと、触媒の下流側に配
設された第２空燃比センサと、これら第１および第２の
空燃比センサの出力を受け、両空燃比センサの出力比に
基づいて第１空燃比センサの故障を検出するセンサ故障
検出手段とを備えた空燃比検出装置の故障検出装置であ
って、エンジンの吸入空気量に関連するパラメータを検
出する吸入空気量検出手段の出力を受け、検出された空
気量が設定値以下の時にセンサ故障検出手段を作動させ
る作動条件設定手段を設けたことを特徴とする。上記吸
入空気量検出手段としては、たとえば、スロットル弁全
閉を検知するアイドルスイッチが利用できる。The first invention of the present application relates to a failure detecting device for an air-fuel ratio detecting device for achieving the above first object, and FIG. 1 (a) shows its entire structure. It is a figure. According to the present invention, as the air-fuel ratio sensor (first air-fuel ratio sensor) on the upstream side of the catalyst deteriorates and the responsiveness deteriorates,
Since the fluctuation of the air-fuel ratio becomes large, the frequency of the output waveform of the air-fuel ratio sensor (second air-fuel ratio sensor) on the downstream side of the catalyst becomes small, but such a phenomenon is particularly off-idle (with load).
In an area where the amount of intake air is small, such as when idling, the cycle of air-fuel ratio fluctuation is originally long, so the influence of responsiveness deterioration of the first air-fuel ratio sensor is small, while the catalyst is If it deteriorates, the O 2 storage effect cannot be obtained regardless of idle or off idle. Therefore, paying attention to the phenomenon that the frequency of the second air-fuel ratio sensor decreases as described above even during idle time. This is due to the knowledge that erroneous determination due to catalyst deterioration can be prevented by detecting deterioration of the fuel ratio sensor, and the structure is such that the upstream of the catalyst for purifying exhaust gas in the exhaust passage of the engine is Which is arranged on the side and outputs an air-fuel ratio signal to the air-fuel ratio control means for feedback controlling the air-fuel ratio of the air-fuel mixture supplied to the engine to the target air-fuel ratio. The air-fuel ratio sensor, the second air-fuel ratio sensor arranged on the downstream side of the catalyst, the outputs of the first and second air-fuel ratio sensors, and the first air-fuel ratio based on the output ratio of both air-fuel ratio sensors A failure detection device for an air-fuel ratio detection device comprising a sensor failure detection means for detecting a sensor failure, which is detected by receiving an output of an intake air amount detection means for detecting a parameter related to an intake air amount of an engine. It is characterized in that an operating condition setting means for activating the sensor failure detecting means is provided when the amount of air is less than a set value. As the intake air amount detecting means, for example, an idle switch for detecting the full closing of the throttle valve can be used.
【００１１】また、この出願の第２の発明は上記第２の
目的を達成するための空燃比検出装置の故障検出装置に
係るものであり、図１（ｂ）はその全体構成図である。
この発明は、空燃比センサのリーンシフト劣化およびリ
ッチシフト劣化が吸収されＰ値センタが収束した後で触
媒の劣化検出を行うようにしたものであり、その構成
は、エンジンの排気通路において排気ガス浄化のための
触媒の上流側に配設され、エンジンに供給される混合気
の空燃比を目標空燃比にフィードバック制御するため空
燃比制御手段に空燃比信号を出力する第１空燃比センサ
と、触媒の下流側に配設された第２空燃比センサと、こ
れら第１および第２の空燃比センサの出力を受け第１空
燃比センサの故障度合を検出するとともに故障度合に応
じて空燃比制御手段による制御を補正するセンサ故障検
出手段とを備えた空燃比検出装置の故障検出装置であっ
て、第１および第２の両空燃比センサの出力に基づいて
前記触媒の劣化を検出する触媒劣化検出装置の作動をセ
ンサ故障検出手段による故障検出と補正が行われるまで
禁止する触媒劣化検出禁止手段を備えたことを特徴とす
る。The second invention of the present application relates to a failure detecting device of an air-fuel ratio detecting device for achieving the second object, and FIG. 1 (b) is an overall configuration diagram thereof.
The present invention is designed to detect the deterioration of the catalyst after the lean shift deterioration and the rich shift deterioration of the air-fuel ratio sensor have been absorbed and the P value center has converged, and the structure is such that the exhaust gas is exhausted in the exhaust passage of the engine. A first air-fuel ratio sensor which is arranged upstream of the catalyst for purification and which outputs an air-fuel ratio signal to air-fuel ratio control means for feedback-controlling the air-fuel ratio of the air-fuel mixture supplied to the engine to a target air-fuel ratio; A second air-fuel ratio sensor arranged downstream of the catalyst and the outputs of the first and second air-fuel ratio sensors are used to detect the degree of failure of the first air-fuel ratio sensor and control the air-fuel ratio according to the degree of failure. A failure detection device for an air-fuel ratio detection device, comprising: a sensor failure detection means for correcting control by the means, wherein deterioration of the catalyst is detected based on outputs of both the first and second air-fuel ratio sensors. Wherein the actuating fault detection and correction by the sensor failure detecting means of the catalyst deterioration detection device provided with a catalyst deterioration detection inhibiting means for inhibiting to be done to.
【００１２】[0012]
【作用】この出願の第１の発明によれば、エンジンの空
燃比は触媒の上流側に配設された第１空燃比センサの出
力に基づいて目標空燃比にフィードバック制御される。
また、アイドル時等のエンジンの吸入空気量が設定値以
下の領域において、センサ故障検出手段が作動し、上記
第１空燃比センサと触媒装置下流側の第２空燃センサの
出力比たとえば周波数比に基づいて第１空燃比センサの
劣化を検出する。According to the first invention of this application, the air-fuel ratio of the engine is feedback-controlled to the target air-fuel ratio based on the output of the first air-fuel ratio sensor arranged upstream of the catalyst.
Further, in a region where the intake air amount of the engine is equal to or less than the set value at the time of idling or the like, the sensor failure detection means operates, and the output ratio of the first air-fuel ratio sensor and the second air-fuel sensor downstream of the catalyst device, for example, the frequency ratio. The deterioration of the first air-fuel ratio sensor is detected based on the above.
【００１３】図２は上記発明の作用を説明するタイムチ
ャートであり、（ａ）はアイドル，オフアイドルを含む
車速モードを示し、（ｂ）は第１空燃比センサの正常時
の出力波形を、（ｃ）は第１空燃比センサの劣化時の出
力波形を、（ｄ）は第１空燃比センサ劣化時の第２空燃
比センサの出力波形を、（ｅ）は第１空燃比センサ正常
時の第２空燃比センサの出力波形を、（ｆ）は触媒劣化
時の第２空燃比センサの出力波形をそれぞれ模式的に示
している。この図に見るように、第１空燃比センサが劣
化すると、その波形は吸入空気量の多いオフアイドルに
おいて周波数が小さくなる。一方、第２空燃比センサの
方は、第１空燃比センサが劣化することによりオフアイ
ドル時の周波数が大きくなって第１空燃比センサとの周
波数比が１に近づくが、吸入空気量の少ないアイドル時
には正常時の波形とさほど変わらない。また、第２空燃
比センサの波形は、触媒が劣化した時にも周波数が大き
くなるが、この場合は吸入空気量の少ないアイドル等の
領域でも周波数が大きくなる。よって、上記のようにア
イドル時等においてセンサ劣化検出が行われることによ
り、触媒の劣化と空燃比センサの劣化の混同が防止さ
れ、第１空燃比センサの劣化が正確に検出される。FIG. 2 is a time chart for explaining the operation of the present invention. FIG. 2A shows a vehicle speed mode including idle and off-idle, and FIG. 2B shows an output waveform of the first air-fuel ratio sensor under normal conditions. (C) shows an output waveform when the first air-fuel ratio sensor deteriorates, (d) shows an output waveform of the second air-fuel ratio sensor when the first air-fuel ratio sensor deteriorates, and (e) shows an output waveform when the first air-fuel ratio sensor is normal. 2F schematically shows the output waveform of the second air-fuel ratio sensor, and (f) schematically shows the output waveform of the second air-fuel ratio sensor when the catalyst deteriorates. As shown in this figure, when the first air-fuel ratio sensor deteriorates, its waveform has a smaller frequency in off-idle with a large intake air amount. On the other hand, in the case of the second air-fuel ratio sensor, the frequency at the time of off idle increases due to deterioration of the first air-fuel ratio sensor, and the frequency ratio with the first air-fuel ratio sensor approaches 1, but the intake air amount is small. When idle, the waveform is not much different from the normal waveform. Further, the waveform of the second air-fuel ratio sensor has a large frequency even when the catalyst is deteriorated, but in this case, the frequency also becomes large even in a region such as an idle where the intake air amount is small. Therefore, by performing the sensor deterioration detection at the time of idling as described above, the confusion of the catalyst deterioration and the air-fuel ratio sensor deterioration is prevented, and the deterioration of the first air-fuel ratio sensor is accurately detected.
【００１４】また、この出願の第２の発明によれば、や
はりエンジンの空燃比は触媒の上流側に配設された第１
空燃比センサの出力に基づいて目標空燃比にフィードバ
ック制御される。そして、センサ故障検出手段は上記第
１空燃比センサの出力と触媒下流側の第２空燃比センサ
の出力を受け、たとえば、第１空燃比センサによる空燃
比制御のＰ値を第２空燃比センサの出力に基づいてフィ
ードバック補正することによりリーンシフトおよびリッ
チシフトの劣化度合の検出とその補正を行う。また、上
記センサ故障検出手段による劣化の検出と補正が行われ
るまでは触媒劣化検出手段の作動が禁止され、触媒の劣
化検出は、空燃比センサの劣化が吸収された状態で第１
空燃比センサと第２空燃比センサの出力比たとえば周波
数比に基づいて行われる。According to the second invention of this application, the air-fuel ratio of the engine is also the first, which is arranged upstream of the catalyst.
Feedback control is performed to the target air-fuel ratio based on the output of the air-fuel ratio sensor. The sensor failure detection means receives the output of the first air-fuel ratio sensor and the output of the second air-fuel ratio sensor on the downstream side of the catalyst, and, for example, sets the P value of the air-fuel ratio control by the first air-fuel ratio sensor to the second air-fuel ratio sensor. By performing feedback correction on the basis of the output of, the degree of deterioration of lean shift and rich shift is detected and corrected. Further, the operation of the catalyst deterioration detecting means is prohibited until the sensor failure detecting means detects and corrects the deterioration, and the catalyst deterioration is detected in the first state when the deterioration of the air-fuel ratio sensor is absorbed.
This is performed based on the output ratio of the air-fuel ratio sensor and the second air-fuel ratio sensor, for example, the frequency ratio.
【００１５】[0015]
【実施例】図３はこの出願に係る第１の発明の一実施例
を示す全体システム図である。図において１はエンジン
本体を示す。エンジン本体１の吸気側には気筒毎の独立
吸気通路２ａが設けられ、これら独立吸気通路２ａはサ
ージタンク２ｂを経て上流側吸気通路２ｃに接続されて
いる。そして、上流側吸気通路２ｃには、先端にエアク
リーナ３に接続され、エアクリーナ３との接続部に近い
上流位置にはエアフローメータ４が、また、サージタン
ク２ｂの入口に近い下流位置にはスロットル弁５が配設
されている。また、エンジン本体１の排気側には排気通
路６が接続され、排気通路６には触媒７が配設されてい
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 is an overall system diagram showing an embodiment of the first invention according to this application. In the figure, 1 indicates an engine body. An independent intake passage 2a for each cylinder is provided on the intake side of the engine body 1, and these independent intake passages 2a are connected to an upstream intake passage 2c via a surge tank 2b. The upstream intake passage 2c is connected to the air cleaner 3 at its tip, an air flow meter 4 is provided at an upstream position near the connection with the air cleaner 3, and a throttle valve is provided at a downstream position near the inlet of the surge tank 2b. 5 are provided. An exhaust passage 6 is connected to the exhaust side of the engine body 1, and a catalyst 7 is arranged in the exhaust passage 6.
【００１６】各気筒の独立吸気通路２ａには燃料噴射用
のインジェクタ８が配設されている。これらインジェク
タ８はマイクロコンピュータ等で構成されたコントロー
ルユニット９によって制御される。そして、このインジ
ェクタ９による燃料噴射量の制御によってエンジンの空
燃比が制御される。そのため、コントロールユニット９
には、上記エアフローメータ４から吸入空気量信号が入
力され、クランク角センサ１０からクランク角信号が、
水温センサ１１からエンジン水温信号が、また、スロッ
トル弁５に付設されたアイドルスイッチからアイドルス
イッチ信号が入力される。また、排気通路６には、触媒
７の上流側に第１空燃比センサ（Ｏ2センサ）１２が、
下流側に第２空燃比センサ（Ｏ2センサ）１３がそれぞ
れ配設され、これら第１および第２の空燃比センサ１
２，１３の検出信号が上記コントロールユニット９に入
力される。An injector 8 for fuel injection is arranged in the independent intake passage 2a of each cylinder. These injectors 8 are controlled by a control unit 9 composed of a microcomputer or the like. The air-fuel ratio of the engine is controlled by controlling the fuel injection amount by the injector 9. Therefore, the control unit 9
Is supplied with the intake air amount signal from the air flow meter 4, and the crank angle signal from the crank angle sensor 10 is
An engine water temperature signal is input from the water temperature sensor 11, and an idle switch signal is input from an idle switch attached to the throttle valve 5. Further, in the exhaust passage 6, a first air-fuel ratio sensor (O 2 sensor) 12 is provided on the upstream side of the catalyst 7.
Second air-fuel ratio sensors (O 2 sensors) 13 are respectively arranged on the downstream side, and the first and second air-fuel ratio sensors 1 are provided.
The detection signals 2 and 13 are input to the control unit 9.
【００１７】コントロールユニット９は、周知のよう
に、エアフローメータ４によって検出された吸入空気量
Ｑａをクランク角信号から演算したエンジン回転数Ｎｅ
で割った値に定数Ｋを掛けて燃料の基本噴射量Ｔ0を設
定し、これをエンジン水温等によって補正する。そし
て、さらに触媒７上流の第１空燃比センサ１２によって
検出された空燃比と目標空燃比との偏差に基づいたフィ
ードバック補正量ＣＦＢを加えて最終噴射量Ｔを設定
し、この最終噴射量Ｔに相当するパルス巾の噴射パルス
を上記インジェクタ８に出力する。これによって、エン
ジンの空燃比は例えば理論空燃比（１４.７）に制御さ
れる。As is well known, the control unit 9 calculates the engine speed Ne by calculating the intake air amount Qa detected by the air flow meter 4 from the crank angle signal.
The value divided by is multiplied by a constant K to set a basic fuel injection amount T 0 , which is corrected by the engine water temperature or the like. Then, the final injection amount T is set by further adding the feedback correction amount CFB based on the deviation between the air-fuel ratio detected by the first air-fuel ratio sensor 12 upstream of the catalyst 7 and the target air-fuel ratio to this final injection amount T. An injection pulse having a corresponding pulse width is output to the injector 8. Thereby, the air-fuel ratio of the engine is controlled to, for example, the stoichiometric air-fuel ratio (14.7).
【００１８】上記フィードバック補正量ＣＦＢは、第２
空燃比センサ１３の出力に基づいたＰ値フィードバック
制御によって補正される。図４はこのＰ値フィードバッ
ク制御を説明するタイムチャートであり、（ａ）は第１
空燃比センサの信号波形を、（ｂ）は第２空燃比センサ
の信号波形を、（ｃ）は空燃比がリッチサイドからリー
ンサイドに移行したときのＣＦＢのＰ値（スキップ値）
であるＣＧＰＦＲＬを、（ｄ）は空燃比がリーンサイド
からリッチサイドに移行したときのＣＦＢのＰ値である
ＣＧＰＦＬＲを、（ｅ）は補正されたＣＦＢをそれぞれ
示している。The feedback correction amount CFB is the second
It is corrected by P value feedback control based on the output of the air-fuel ratio sensor 13. FIG. 4 is a time chart explaining this P-value feedback control, in which (a) is the first chart.
The signal waveform of the air-fuel ratio sensor, (b) the signal waveform of the second air-fuel ratio sensor, and (c) the P value (skip value) of CFB when the air-fuel ratio shifts from the rich side to the lean side.
Shows CGPFRL, (d) shows CGPFLR, which is the P value of CFB when the air-fuel ratio shifts from the lean side to the rich side, and (e) shows the corrected CFB.
【００１９】第２空燃比センサ１３の出力は、Ｐ値フィ
ードバックをしなければリッチ側あるいはリーン側にほ
ぼ張り付いた形となる。また、Ｐ値フィードバックをし
た場合には、空燃比の振れが大きくなって触媒の浄化ウ
インドウから外れやすくなるため、第２空燃比センサ１
３は変動波形を示すようになる。この第２空燃比センサ
１３の波形は、第１空燃比センサ１２が正常であれば変
動周期の長い波形となり、第１空燃比センサ１２が劣化
するとその周期が短くなる。Ｐ値フィードバック制御
は、この第１空燃比センサの劣化を検出してＣＦＢのＰ
値を補正するものであって、第２空燃比センサ１３の出
力がリッチ側に張り付いている間は単位時間（例えば
８.２ｍｓ）毎に微小割合ΔＳＫＩＰ（例えば０.２％）
ずつＣＧＰＦＲＬを小さくしてＣＧＰＦＬＲを大きく
し、第２空燃比センサ１３の出力がリーン側に張り付い
ている間はやはりΔＳＫＩＰずつＣＧＰＦＲＬを大きく
してＣＧＰＦＬＲを小さくする。これにより、ＣＧＰＦ
ＬＲおよびＣＧＰＦＲＬのセンタ（平均値）は第１空燃
比センタ１２の劣化度合に応じた値に収束し、劣化が吸
収される。The output of the second air-fuel ratio sensor 13 will be in the form of sticking to the rich side or the lean side without P value feedback. Further, when the P value feedback is performed, the fluctuation of the air-fuel ratio becomes large and it becomes easy to deviate from the purification window of the catalyst, so the second air-fuel ratio sensor 1
3 shows a fluctuation waveform. The waveform of the second air-fuel ratio sensor 13 has a long fluctuation cycle if the first air-fuel ratio sensor 12 is normal, and the cycle becomes short when the first air-fuel ratio sensor 12 deteriorates. The P value feedback control detects the deterioration of the first air-fuel ratio sensor and detects the PB of the CFB.
The value is corrected, and while the output of the second air-fuel ratio sensor 13 is stuck to the rich side, a minute ratio ΔSKIP (for example, 0.2%) every unit time (for example, 8.2 ms).
The CGPFRL is decreased to increase the CGPFLR, and while the output of the second air-fuel ratio sensor 13 is stuck to the lean side, the CGPFRL is increased by ΔSKIP to decrease the CGPFLR. As a result, CGPF
The center (average value) of LR and CGPFRL converges to a value according to the degree of deterioration of the first air-fuel ratio center 12, and the deterioration is absorbed.
【００２０】コントロールユニット９は、また、第１空
燃比センサ１２の周波数劣化を判定し、劣化判定信号を
出力する。第１空燃比センサ１２が周波数劣化すると、
その出力波形の周波数はオフアイドル時ににおいて小さ
くなり、一方、第２空燃比センサ１３の周波数はオフア
イドル時に大きくなって第１空燃比センサ１２との周波
数比が１に近づく。ただし、第２空燃比センサ１３の周
波数が大きくなる現象は触媒７の劣化時にも同様に現れ
る。また、第２空燃比センサ１３の周波数はアイドル時
には第１空燃比センサ１２の劣化の影響をあまり受けな
い。そこで、まず、オフアイドル時の両センサ１２，１
３の周波数比を見て、その周波数比がほぼ１になれば、
次いで、アイドル時の周波数比を見て、これがしきい値
を越えれば第１空燃比センサ１２の周波数劣化と判定す
る。ここで、アイドル時およびオフアイドル時の判定は
アイドルスイッチ信号によって行う。The control unit 9 also judges the frequency deterioration of the first air-fuel ratio sensor 12 and outputs a deterioration judgment signal. When the frequency of the first air-fuel ratio sensor 12 deteriorates,
The frequency of the output waveform decreases at the time of off-idling, while the frequency of the second air-fuel ratio sensor 13 increases at the time of off-idling, and the frequency ratio with the first air-fuel ratio sensor 12 approaches 1. However, the phenomenon that the frequency of the second air-fuel ratio sensor 13 increases becomes similar when the catalyst 7 deteriorates. Further, the frequency of the second air-fuel ratio sensor 13 is not so much affected by the deterioration of the first air-fuel ratio sensor 12 during idling. Therefore, first, both sensors 12, 1 at the time of off idle
Looking at the frequency ratio of 3, if the frequency ratio becomes almost 1,
Next, the frequency ratio during idling is checked, and if it exceeds the threshold value, it is determined that the frequency of the first air-fuel ratio sensor 12 has deteriorated. The idle switch signal is used to determine whether the engine is idle or off-idle.
【００２１】図５は上記実施例の周波数劣化検出の制御
を実行するためのフローチャートであり、Ｓ１０１〜１
０４はその各ステップを示す。このフローでは、スター
トすると、Ｓ１０１でオフアイドル時の第１空燃比セン
サ（フロントＯ2）の周波数と第２空燃比センサ（リア
Ｏ2）の周波数の比が１かどうかを見る。そして、周波
数比が１である（ＹＥＳ）ということであれば、Ｓ１０
２へ行って、今度はアイドル時の周波数比がしきい値Ｋ
を越えているかどうかを見て、周波数比がＫを越えてい
る（ＹＥＳ）ということであれば、Ｓ１０３で第１空燃
比センサの周波数劣化と判定してリターンする。FIG. 5 is a flow chart for executing the control of the frequency deterioration detection of the above embodiment, and S101 to S1.
Reference numeral 04 indicates each step. In this flow, when starting, it is checked in S101 whether the ratio of the frequency of the first air-fuel ratio sensor (front O 2 ) and the frequency of the second air-fuel ratio sensor (rear O 2 ) at the time of off idle is 1. If the frequency ratio is 1 (YES), S10
Go to 2 and this time the frequency ratio at idle is the threshold value K
If the frequency ratio exceeds K (YES), it is determined in S103 that the frequency of the first air-fuel ratio sensor has deteriorated, and the process returns.
【００２２】また、オフアイドル時の周波数比が１でな
い（Ｓ１０１でＮＯ）という場合、あるいは、オフアイ
ドル時の周波数比が１であってもアイドル時の周波数比
がＫ以下（Ｓ１０２でＮＯ）というときは、Ｓ１０４へ
行って触媒（キャタ）の劣化判定を行い、リターンす
る。Further, if the frequency ratio during off idle is not 1 (NO in S101), or even if the frequency ratio during off idle is 1, the frequency ratio during idle is K or less (NO in S102). In this case, the process proceeds to S104, the deterioration determination of the catalyst (catalyst) is performed, and the process returns.
【００２３】図６は、この出願に係る第２の発明の一実
施例における制御を実行するためのフローチャートであ
る。この実施例は、排気通路に配設した触媒の劣化検出
を空燃比センサのリーンシフトおよびリッチシフトの劣
化が検出され補正された後で実行するようにしたもので
あって、全体システム図は先の実施例に係る図３と同様
である。この場合も、やはり空燃比フィードバック制御
を行い、また、Ｐ値フィードバック制御を行う。以下、
図６のフローによってこの実施例の制御を説明する。な
お、Ｓ２０１〜２２２はこのフローの各ステップを示
す。FIG. 6 is a flow chart for executing control in one embodiment of the second invention according to this application. In this embodiment, the deterioration of the catalyst arranged in the exhaust passage is detected after the deteriorations of the lean shift and the rich shift of the air-fuel ratio sensor are detected and corrected, and the entire system diagram is not shown in the above. 3 according to the embodiment of FIG. Also in this case, the air-fuel ratio feedback control is also performed, and the P value feedback control is also performed. Less than,
The control of this embodiment will be described with reference to the flow chart of FIG. Note that S201 to 222 indicate each step of this flow.
【００２４】図６のフローにおいて、スタートすると、
まずＳ２０１で第１空燃比センサ（フロントＯ2）が活
性かどうかを判定する。そして、活性である（ＹＥＳ）
ということであれば、Ｓ２０２へ進んで空燃比フィード
バック制御を実行し、つぎに、Ｓ２０３で第２空燃比セ
ンサ（リアＯ2）が活性かどうかを判定する。In the flow of FIG. 6, when starting,
First, in S201, it is determined whether or not the first air-fuel ratio sensor (front O 2 ) is active. And is active (YES)
If so, the routine proceeds to S202, where air-fuel ratio feedback control is executed, and then at S203, it is determined whether or not the second air-fuel ratio sensor (rear O 2 ) is active.
【００２５】Ｓ２０３の判定がＹＥＳで第１空燃比セン
サおよび第２空燃比センサがいずれも活性であれば、Ｓ
２０４でＰ値フィードバック制御の実行フラッグを立て
る。そして、Ｓ２０５で第２空燃比センサの出力がスラ
イスレベル（設定値）以上であるかどうかを見て、スラ
イスレベル以上である（ＹＥＳ）という時はＳ２０６で
リッチフラッグを立て、Ｓ２０７でＣＧＰＦＬＲをΔＳ
ＫＩＰだけ大きくし、また、ＣＧＰＦＲＬをΔＳＫＩＰ
だけ小さくする。If the determination in S203 is YES and both the first air-fuel ratio sensor and the second air-fuel ratio sensor are active, S
At 204, an execution flag of P value feedback control is set. Then, in S205, it is determined whether or not the output of the second air-fuel ratio sensor is equal to or higher than the slice level (set value), and if it is equal to or higher than the slice level (YES), a rich flag is set in S206, and CGPFLR is changed to ΔS in S207.
Increase KIP only, and increase CGPFRL by ΔSKIP
Just make it smaller.
【００２６】また、第２空燃比センサの出力がスライス
レベルより低い（Ｓ２０５でＮＯ）という時は、Ｓ２０
８でリーンフラッグを立て、Ｓ２０９でＣＧＰＦＬＲを
ΔＳＫＩＰだけ小さくし、また、ＣＧＰＦＲＬをΔＳＫ
ＩＰだけ大きくする。If the output of the second air-fuel ratio sensor is lower than the slice level (NO in S205), S20 is set.
Set a lean flag at 8 and reduce CGPFLR by ΔSKIP at S209, and CGPFRL at ΔSK.
Increase only IP.
【００２７】また、第２空燃比センサが活性でない（Ｓ
２０３でＮＯ）という時は、Ｓ２１０でＰ値フィードバ
ック制御の実行フラッグを降ろす。そして、Ｓ２１１へ
行ってＣＧＰＦＬＲおよびＣＧＰＦＲＬをいずれも前回
値で更新する。Further, the second air-fuel ratio sensor is not active (S
If the answer is NO in 203, the execution flag of the P value feedback control is lowered in S210. Then, the process proceeds to S211, and both CGPFLR and CGPFRL are updated with the previous values.
【００２８】Ｓ２０７あるいはＳ２０８でＣＧＰＦＬＲ
あるいはＣＧＰＦＲＬの増減を行った時は、つぎに、Ｓ
２１２でＣＧＰ（ＣＧＰＦＬＲおよびＣＧＰＦＲＬ）の
平均値がフェイル判定しきい値を越えていないかどうか
を見る。そして、しきい値を越えていない（ＹＥＳ）と
いうことであれば、Ｓ２１３へ進み、今回のフェイル判
定しきい値とＣＧＰ平均値の差Ｂと前回のフェイル判定
しきい値とＣＧＰ平均値の差Ｂ（ｉ−１）すなわちＢ−
Ｂ（ｉ−１）の値ΔＡを求め、このΔＡがＣＧＰの収束
判定しきい値以下となったかどうかによって、Ｐ値制御
が収束したかどうかを判定する。そして、ΔＡがＣＧＰ
の収束判定しきい値以下となった（ＹＥＳ）ということ
であれば、Ｓ２１４でＣＧＰ収束判定フラッグを立て、
Ｓ２１５でシステム正常の判定を行い、Ｓ２１６でフィ
ードバック補正量（ＣＦＢ）の演算を実行し、その後、
Ｓ２１７で触媒劣化検出を実行する。CGPFLR in S207 or S208
Or, when CGPFRL is increased or decreased, then S
At 212, see if the average value of CGP (CGPFLR and CGPFRL) exceeds the fail decision threshold. If the threshold is not exceeded (YES), the process proceeds to S213, where the difference B between the current fail determination threshold and the CGP average value and the difference between the previous fail determination threshold and the CGP average value. B (i-1) or B-
The value ΔA of B (i−1) is obtained, and whether or not the P value control has converged is determined depending on whether or not this ΔA has become equal to or less than the CGP convergence determination threshold value. And ΔA is CGP
If it is equal to or less than the convergence determination threshold value of (YES), a CGP convergence determination flag is set in S214,
The system normality is determined in S215, the feedback correction amount (CFB) is calculated in S216, and then,
Catalyst deterioration detection is executed in S217.
【００２９】また、Ｓ２１３の判定で、ΔＡがＣＧＰの
収束判定しきい値以下となっていなければ（ＮＯ）、Ｓ
２１８へ行ってＣＧＰ収束判定フラッグを降ろし、Ｓ２
１９でＣＦＢ演算を実行した後、そのままリターンす
る。If ΔA is not less than or equal to the CGP convergence determination threshold value in the determination in S213 (NO), S
Go to step 218, clear the CGP convergence determination flag, and press S2.
After the CFB calculation is executed at 19, the process directly returns.
【００３０】また、Ｓ２１２の判定がＮＯすなわちＣＧ
Ｐ平均値がしきい値を越えたという場合は、Ｓ２２０へ
行ってシステム異常の判定を行い、Ｓ２２１でランプを
点灯する。The determination in S212 is NO, that is, CG.
If the P average value exceeds the threshold value, the process goes to S220 to determine the system abnormality, and the lamp is turned on in S221.
【００３１】また、第１空燃比センサが活性でない（Ｓ
２０１でＮＯ）という時は、空燃比フィードバックは実
行しないので、Ｓ２２２でＣＦＢを固定する。Further, the first air-fuel ratio sensor is not active (S
When the answer is NO in 201, the air-fuel ratio feedback is not executed, so the CFB is fixed in S222.
【００３２】[0032]
【発明の効果】この出願の発明は以上のように構成され
ているので、第１の発明によれば、触媒の下流側に配設
した第２空燃比センサの出力により上流側の第１空燃比
センサの劣化を検出するに際し、触媒の劣化と混同する
ことなく第１空燃比センサの劣化を正確に検出できる。Since the invention of this application is constituted as described above, according to the first invention, the output of the second air-fuel ratio sensor disposed on the downstream side of the catalyst is used to output the first air on the upstream side. When detecting the deterioration of the fuel ratio sensor, the deterioration of the first air-fuel ratio sensor can be accurately detected without being confused with the deterioration of the catalyst.
【００３３】また、この出願の第２の発明によれば、第
２空燃比センサの出力に基づいて第１空燃比センサの劣
化を検出し補正するに際し、第１空燃比センサの劣化度
合の影響を受けずに触媒の劣化を正確に検出できる。Further, according to the second invention of this application, when the deterioration of the first air-fuel ratio sensor is detected and corrected based on the output of the second air-fuel ratio sensor, the influence of the deterioration degree of the first air-fuel ratio sensor. The deterioration of the catalyst can be accurately detected without being affected.
【図面の簡単な説明】[Brief description of drawings]
【図１】この出願の第１および第２の発明の全体構成図FIG. 1 is an overall configuration diagram of first and second inventions of this application.
【図２】この出願の第１の発明の作用を説明するタイム
チャートFIG. 2 is a time chart explaining the operation of the first invention of this application.
【図３】この出願の第１の発明の一実施例の全体システ
ム図FIG. 3 is an overall system diagram of an embodiment of the first invention of this application.
【図４】この出願の第１の発明の一実施例におけるＰ値
フィードバック制御を説明するタイムチャートFIG. 4 is a time chart for explaining P value feedback control in one embodiment of the first invention of this application.
【図５】この出願の第１の発明の一実施例における空燃
比センサの周波数劣化検出の制御を実行するフローチャ
ートFIG. 5 is a flowchart for executing control of frequency deterioration detection of the air-fuel ratio sensor in the embodiment of the first invention of this application.
【図６】この出願の第２の発明の一実施例の制御を実行
するフローチャートFIG. 6 is a flowchart for executing control of one embodiment of the second invention of this application.
１ エンジン本体 ６ 排気通路 ７ 触媒 ８ インジェクタ ９ コントロールユニット １２ 第１空燃比センサ １３ 第２空燃比センサ 1 Engine Body 6 Exhaust Passage 7 Catalyst 8 Injector 9 Control Unit 12 First Air-Fuel Ratio Sensor 13 Second Air-Fuel Ratio Sensor
Claims (2)
化のための触媒の上流側に配設され、該エンジンに供給
される混合気の空燃比を目標空燃比にフィードバック制
御するため空燃比制御手段に空燃比信号を出力する第１
空燃比センサと、前記触媒の下流側に配設された第２空
燃比センサと、これら第１および第２の空燃比センサの
出力を受け、両空燃比センサの出力比に基づいて前記第
１空燃比センサの故障を検出するセンサ故障検出手段と
を備えた空燃比検出装置において、前記エンジンの吸入
空気量に関連するパラメータを検出する吸入空気量検出
手段の出力を受け、検出された空気量が設定値以下の時
に前記センサ故障検出手段を作動させる作動条件設定手
段を設けたことを特徴とする空燃比検出装置の故障検出
装置。1. An air-fuel ratio control means for feedback-controlling an air-fuel ratio of an air-fuel mixture supplied to the engine in an exhaust passage of an engine upstream of a catalyst for purifying exhaust gas. First to output air-fuel ratio signal
The first air-fuel ratio sensor, the second air-fuel ratio sensor disposed on the downstream side of the catalyst, and the outputs of the first and second air-fuel ratio sensors are received, and the first air-fuel ratio sensor outputs the first air-fuel ratio sensor based on the output ratio of both air-fuel ratio sensors. In an air-fuel ratio detecting device having a sensor failure detecting means for detecting a failure of an air-fuel ratio sensor, the detected air quantity is received by an output of an intake air quantity detecting means for detecting a parameter related to the intake air quantity of the engine. A failure detection device for an air-fuel ratio detection device, characterized in that an operation condition setting means for operating the sensor failure detection means is provided when is less than or equal to a set value.
化のための触媒の上流側に配設され、該エンジンに供給
される混合気の空燃比を目標空燃比にフィードバック制
御するため空燃比制御手段に空燃比信号を出力する第１
空燃比センサと、前記触媒の下流側に配設された第２空
燃比センサと、これら第１および第２の空燃比センサの
出力を受け前記第１空燃比センサの故障度合を検出する
とともに故障度合に応じて前記空燃比制御手段による制
御を補正するセンサ故障検出手段とを備えた空燃比検出
装置において、前記第１および第２の両空燃比センサの
出力比に基づいて前記触媒の劣化を検出する触媒劣化検
出装置の作動を前記センサ故障検出手段による故障検出
と補正が行われるまで禁止する触媒劣化検出禁止手段を
設けたことを特徴とする空燃比検出装置の故障検出装
置。2. An air-fuel ratio control means for feedback-controlling an air-fuel ratio of an air-fuel mixture supplied to the engine to a target air-fuel ratio, which is arranged upstream of a catalyst for purifying exhaust gas in an exhaust passage of the engine. First to output air-fuel ratio signal
An air-fuel ratio sensor, a second air-fuel ratio sensor arranged on the downstream side of the catalyst, and outputs of the first and second air-fuel ratio sensors to detect a failure degree of the first air-fuel ratio sensor and to detect a failure. In an air-fuel ratio detection device comprising a sensor failure detection means for correcting the control by the air-fuel ratio control means according to the degree, deterioration of the catalyst based on the output ratio of the first and second air-fuel ratio sensors A failure detection device for an air-fuel ratio detection device, comprising catalyst deterioration detection prohibition means for prohibiting the operation of the catalyst deterioration detection device for detection until failure detection and correction by the sensor failure detection means are performed.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03330421A JP3122856B2 (en) | 1991-12-13 | 1991-12-13 | Air-fuel ratio detection device failure detection device and engine control device |
| US07/988,274 US5337555A (en) | 1991-12-13 | 1992-12-14 | Failure detection system for air-fuel ratio control system |
| US08/195,671 US5414995A (en) | 1991-12-13 | 1994-02-16 | Failure detection system for air-fuel ratio control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP03330421A JP3122856B2 (en) | 1991-12-13 | 1991-12-13 | Air-fuel ratio detection device failure detection device and engine control device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05163984A true JPH05163984A (en) | 1993-06-29 |
| JP3122856B2 JP3122856B2 (en) | 2001-01-09 |
Family
ID=18232421
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP03330421A Expired - Fee Related JP3122856B2 (en) | 1991-12-13 | 1991-12-13 | Air-fuel ratio detection device failure detection device and engine control device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3122856B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0694684A2 (en) * | 1994-07-19 | 1996-01-31 | MAGNETI MARELLI S.p.A. | Electronic gas concentration control system |
| EP0694685A2 (en) * | 1994-07-19 | 1996-01-31 | MAGNETI MARELLI S.p.A. | Electronic gas concentration control system |
| US7139658B2 (en) | 2003-11-10 | 2006-11-21 | Toyota Jidosha Kabushiki Kaisha | Apparatus detecting abnormality of exhaust system of internal combustion engine |
-
1991
- 1991-12-13 JP JP03330421A patent/JP3122856B2/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0694684A2 (en) * | 1994-07-19 | 1996-01-31 | MAGNETI MARELLI S.p.A. | Electronic gas concentration control system |
| EP0694685A2 (en) * | 1994-07-19 | 1996-01-31 | MAGNETI MARELLI S.p.A. | Electronic gas concentration control system |
| EP0694684A3 (en) * | 1994-07-19 | 1996-09-11 | Magneti Marelli Spa | Electronic gas concentration control system |
| EP0694685A3 (en) * | 1994-07-19 | 1996-09-18 | Magneti Marelli Spa | Electronic gas concentration control system |
| US5637276A (en) * | 1994-07-19 | 1997-06-10 | MAGNETI MARELLI S.p.A. | Electronic concentration control system |
| US5697214A (en) * | 1994-07-19 | 1997-12-16 | MAGNETI MARELLI S.p.A. | Electronic concentration control system |
| EP0952322A2 (en) * | 1994-07-19 | 1999-10-27 | MAGNETI MARELLI S.p.A. | Electronic air-fuel ratio control system for internal combustion engines |
| EP0952322A3 (en) * | 1994-07-19 | 1999-11-03 | MAGNETI MARELLI S.p.A. | Electronic air-fuel ratio control system for internal combustion engines |
| US7139658B2 (en) | 2003-11-10 | 2006-11-21 | Toyota Jidosha Kabushiki Kaisha | Apparatus detecting abnormality of exhaust system of internal combustion engine |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3122856B2 (en) | 2001-01-09 |
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