JPH07109918A - Catalysis degradation diagnosing device for internal combustion engine - Google Patents
Catalysis degradation diagnosing device for internal combustion engineInfo
- Publication number
- JPH07109918A JPH07109918A JP5255943A JP25594393A JPH07109918A JP H07109918 A JPH07109918 A JP H07109918A JP 5255943 A JP5255943 A JP 5255943A JP 25594393 A JP25594393 A JP 25594393A JP H07109918 A JPH07109918 A JP H07109918A
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- Prior art keywords
- catalyst
- fuel ratio
- air
- exhaust
- engine
- Prior art date
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- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Testing Of Engines (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は内燃機関の触媒劣化診断
装置に関し、詳しくは、機関排気通路に排気浄化のため
に設けられる触媒の劣化を、排気中の酸素濃度検出に基
づいて診断する装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst deterioration diagnosing device for an internal combustion engine, and more particularly to a device for diagnosing deterioration of a catalyst provided in an engine exhaust passage for purifying exhaust gas based on detection of oxygen concentration in exhaust gas. Regarding
【０００２】[0002]
【従来の技術】従来、機関排気通路に介装された排気浄
化触媒の劣化を診断する装置としては、例えば特開平２
−９１４４０号公報に開示されるものがあった。このも
のは、排気通路に介装された三元触媒の上流側及び下流
側にそれぞれ酸素センサを備え、これら酸素センサの出
力に基づいて理論空燃比を目標空燃比として空燃比フィ
ードバック制御を行う構成の機関において、前記空燃比
フィードバック制御中における上流側の酸素センサの反
転周期と下流側の酸素センサの反転周期との比に基づい
て触媒劣化を診断するものである。2. Description of the Related Art Conventionally, as a device for diagnosing the deterioration of an exhaust purification catalyst provided in an engine exhaust passage, for example, Japanese Patent Laid-Open No. Hei 2 (1999) -29200 is known.
There was one disclosed in Japanese Patent Publication No. 91440. This is equipped with oxygen sensors on the upstream side and the downstream side of the three-way catalyst interposed in the exhaust passage, and performs air-fuel ratio feedback control using the theoretical air-fuel ratio as the target air-fuel ratio based on the output of these oxygen sensors. In this engine, the catalyst deterioration is diagnosed based on the ratio of the inversion cycle of the upstream oxygen sensor and the inversion cycle of the downstream oxygen sensor during the air-fuel ratio feedback control.
【０００３】即ち、前記診断方法は、三元触媒の劣化に
よる酸素ストレージ効果（酸素貯蔵能力）の低下を前記
反転周期の比に基づいて判定し、以て、触媒の劣化診断
を行わせるものである。That is, the above-mentioned diagnosis method is to judge the deterioration of the oxygen storage effect (oxygen storage capacity) due to the deterioration of the three-way catalyst based on the ratio of the reversal period, and to make the deterioration diagnosis of the catalyst. is there.
【０００４】[0004]
【発明が解決しようとする課題】ところで、近年におい
ては、理論空燃比よりも大幅に希薄な空燃比域（例えば
20〜25程度の空燃比）で燃焼させる希薄燃焼機関が開発
されている。かかる希薄燃焼機関では、排気が酸素過剰
状態となるため、酸素濃度が急変する理論空燃比を中心
として空燃比をフィードバック制御する場合のように、
前記酸素濃度の変化周期の比に基づいて触媒劣化を高精
度に診断させることは困難であるという問題があった。By the way, in recent years, in the air-fuel ratio region (for example, much leaner than the theoretical air-fuel ratio) (for example,
A lean-burn engine that burns at an air-fuel ratio of 20 to 25) has been developed. In such a lean burn engine, since the exhaust gas is in an oxygen excess state, as in the case of performing feedback control of the air-fuel ratio centering on the theoretical air-fuel ratio at which the oxygen concentration suddenly changes,
There is a problem that it is difficult to diagnose the catalyst deterioration with high accuracy based on the ratio of the change cycle of the oxygen concentration.
【０００５】本発明は上記問題点に鑑みなされたもので
あり、希薄燃焼が行われる状態であっても、触媒劣化を
排気中の酸素濃度検出に基づいて精度良く診断できる診
断装置を提供することを目的とする。The present invention has been made in view of the above problems, and provides a diagnostic device capable of accurately diagnosing catalyst deterioration based on detection of oxygen concentration in exhaust gas even in a state where lean combustion is performed. With the goal.
【０００６】[0006]
【課題を解決するための手段】そのため本発明にかかる
内燃機関の触媒劣化診断装置は、図１に示すように構成
される。図１において、排気浄化触媒は、機関の排気通
路に設けられるものであり、空燃比フィードバック制御
手段は、機関吸入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。Therefore, a catalyst deterioration diagnosing device for an internal combustion engine according to the present invention is constructed as shown in FIG. In FIG. 1, the exhaust purification catalyst is provided in the exhaust passage of the engine, and the air-fuel ratio feedback control means feedback-controls the air-fuel ratio of the engine intake air-fuel mixture to the target air-fuel ratio.
【０００７】ここで、触媒劣化診断のために、前記排気
浄化触媒の下流側に、排気中の酸素濃度を広域に検出す
る酸素センサが設けられ、触媒劣化診断手段は、前記空
燃比フィードバック制御手段による空燃比フィードバッ
ク制御時における前記酸素センサの出力値と前記目標空
燃比に対応する基準値との偏差に基づいて前記排気浄化
触媒の劣化を診断する。Here, for the purpose of diagnosing the catalyst deterioration, an oxygen sensor for detecting a wide range of oxygen concentration in the exhaust is provided downstream of the exhaust purification catalyst, and the catalyst deterioration diagnosing means is the air-fuel ratio feedback control means. Deterioration of the exhaust purification catalyst is diagnosed on the basis of the deviation between the output value of the oxygen sensor and the reference value corresponding to the target air-fuel ratio during the air-fuel ratio feedback control.
【０００８】[0008]
【作用】排気浄化触媒の劣化が発生すると、酸化・還元
の反応が低下することにより、触媒上流側における酸素
濃度が同じでも前記触媒作用の低下により触媒下流側に
おける酸素濃度に変化を来すことになる。そこで、目標
空燃比に制御されていることを条件とすることで、触媒
上流側の酸素濃度を規定し、このときの触媒下流側にお
ける酸素濃度が、触媒の非劣化状態で期待される出力を
示すか否かによって、触媒劣化による触媒下流側での酸
素濃度の変化を検知できるようにした。[Function] When the exhaust purification catalyst deteriorates, the oxidation / reduction reaction decreases, and even if the oxygen concentration on the upstream side of the catalyst is the same, the oxygen concentration on the downstream side of the catalyst changes due to the decrease in the catalytic action. become. Therefore, the oxygen concentration on the upstream side of the catalyst is regulated under the condition that it is controlled to the target air-fuel ratio, and the oxygen concentration on the downstream side of the catalyst at this time is the output expected in the non-deteriorated state of the catalyst. The change in oxygen concentration on the downstream side of the catalyst due to catalyst deterioration can be detected depending on whether or not it is shown.
【０００９】[0009]
【実施例】以下に本発明の実施例を説明する。一実施例
を示す図２において、内燃機関１には、エアクリーナ２
から吸気ダクト３，スロットル弁４及び吸気マニホール
ド５を介して空気が吸入される。吸気マニホールド５の
ブランチ部には各気筒毎に燃料噴射弁６が設けられてい
る。前記燃料噴射弁６は、ソレノイドに通電されて開弁
し、通電停止されて閉弁する電磁式燃料噴射弁であっ
て、後述するコントロールユニット12からの噴射パルス
信号により通電されて開弁し、図示しない燃料ポンプか
ら圧送されプレッシャレギュレータにより所定の圧力に
調整された燃料を吸気マニホールド５内に噴射供給す
る。EXAMPLES Examples of the present invention will be described below. In FIG. 2 showing an embodiment, the internal combustion engine 1 includes an air cleaner 2
Air is sucked through the intake duct 3, the throttle valve 4 and the intake manifold 5. At the branch portion of the intake manifold 5, a fuel injection valve 6 is provided for each cylinder. The fuel injection valve 6 is an electromagnetic fuel injection valve that is energized by a solenoid to open the valve, is deenergized and is closed, and is energized by an injection pulse signal from a control unit 12 described later to open the valve. Fuel that is pressure-fed from a fuel pump (not shown) and adjusted to a predetermined pressure by a pressure regulator is injected and supplied into the intake manifold 5.
【００１０】機関１の燃焼室にはそれぞれ点火栓７が設
けられていて、これにより火花点火して混合気を着火燃
焼させる。そして、機関１からは、排気マニホールド
８，排気ダクト９，排気浄化用の三元触媒10（排気浄化
触媒）及びマフラー11を介して排気が排出される。コン
トロールユニット12は、ＣＰＵ，ＲＯＭ，ＲＡＭ，Ａ／
Ｄ変換器及び入出力インタフェイスを含んで構成される
マイクロコンピュータを備え、各種のセンサからの検出
信号を入力して、後述の如く演算処理して、燃料噴射弁
６の作動を制御する。A spark plug 7 is provided in each combustion chamber of the engine 1 to spark-ignite and ignite and burn the air-fuel mixture. Exhaust gas is discharged from the engine 1 through the exhaust manifold 8, the exhaust duct 9, the exhaust purification three-way catalyst 10 (exhaust purification catalyst), and the muffler 11. The control unit 12 includes a CPU, ROM, RAM, A /
A microcomputer including a D converter and an input / output interface is provided, and detection signals from various sensors are input and arithmetic processing is performed as described later to control the operation of the fuel injection valve 6.
【００１１】前記各種のセンサとしては、吸気ダクト３
中に熱線式或いはフラップ式などのエアフローメータ13
が設けられていて、機関１の吸入空気量Ｑに応じた信号
を出力する。また、クランク角センサ14が設けられてい
て、所定ピストン位置毎の基準角度信号ＲＥＦと、単位
角度毎の単位角度信号ＰＯＳとを出力する。ここで、前
記基準角度信号ＲＥＦの発生周期、或いは、所定時間内
における前記単位角度信号ＰＯＳの発生数を計測するこ
とより、機関回転速度Ｎｅを算出することができる。As the various sensors, the intake duct 3 is used.
Hot wire type or flap type air flow meter 13
Is provided and outputs a signal according to the intake air amount Q of the engine 1. Further, a crank angle sensor 14 is provided and outputs a reference angle signal REF for each predetermined piston position and a unit angle signal POS for each unit angle. Here, the engine rotation speed Ne can be calculated by measuring the generation cycle of the reference angle signal REF or the number of generations of the unit angle signal POS within a predetermined time.
【００１２】また、機関１のウォータジャケットの冷却
水温度Ｔｗを検出する水温センサ15が設けられている。
更に、前記三元触媒10の上流側となる排気マニホールド
８の集合部に空燃比フィードバック制御に用いるための
第１酸素センサ16が設けられており、また、前記三元触
媒10の下流側でマフラー11の上流側には後述するように
触媒劣化診断に用いる第２酸素センサ17が設けられてい
る。A water temperature sensor 15 for detecting the cooling water temperature Tw of the water jacket of the engine 1 is also provided.
Further, a first oxygen sensor 16 for use in air-fuel ratio feedback control is provided in the exhaust manifold 8 upstream of the three-way catalyst 10, and a muffler is provided downstream of the three-way catalyst 10. A second oxygen sensor 17 used for catalyst deterioration diagnosis is provided on the upstream side of 11, as will be described later.
【００１３】前記第１酸素センサ16及び第２酸素センサ
17は、機関吸入混合気の空燃比と密接な関係にある排気
中の酸素濃度に感応して出力値が変化する公知のセンサ
であり、理論空燃比からリーン領域を広域に検出し得る
センサ（リーンセンサ）であり、図４に示すような出力
特性を有する（株式会社 山海堂，平成４年５月１日発
行「内燃機関」第63頁〜第72頁等参照）。The first oxygen sensor 16 and the second oxygen sensor
Reference numeral 17 is a known sensor whose output value changes in response to the oxygen concentration in the exhaust gas, which has a close relationship with the air-fuel ratio of the engine intake air-fuel mixture, and which can detect a wide lean region from the theoretical air-fuel ratio ( It is a lean sensor) and has output characteristics as shown in FIG. 4 (see Sankaido Co., Ltd., May 1, 1992, "Internal Combustion Engine", pages 63 to 72, etc.).
【００１４】また、機関１が搭載された車両の走行速度
を検出する車速センサ18が設けられている。ここにおい
て、コントロールユニット12に内蔵されたマイクロコン
ピュータのＣＰＵは、各センサで検出される運転条件に
応じて機関吸入混合気の目標空燃比を、理論空燃比付近
の出力空燃比と、理論空燃比よりも大幅に希薄な希薄空
燃比（例えば空燃比＝22）とに切り換え制御し、それぞ
れの目標空燃比に実際の空燃比を一致させるべく、基本
燃料噴射パルス幅Ｔｐを演算する一方、前記第１酸素セ
ンサ16で検出される実際の空燃比に基づいて前記基本燃
料噴射パルス幅Ｔｐをフィードバック補正する空燃比フ
ィードバック制御機能（空燃比フィードバック制御手段
としての機能）を有している。A vehicle speed sensor 18 for detecting the traveling speed of a vehicle equipped with the engine 1 is also provided. Here, the CPU of the microcomputer built in the control unit 12 sets the target air-fuel ratio of the engine intake air-fuel mixture to the output air-fuel ratio near the theoretical air-fuel ratio and the theoretical air-fuel ratio according to the operating conditions detected by each sensor. The basic fuel injection pulse width Tp is calculated so that the lean air-fuel ratio (for example, the air-fuel ratio = 22) is controlled to be significantly leaner than that, and the actual air-fuel ratio is made to match each target air-fuel ratio. 1 has an air-fuel ratio feedback control function (function as air-fuel ratio feedback control means) for performing feedback correction of the basic fuel injection pulse width Tp based on the actual air-fuel ratio detected by the oxygen sensor 16.
【００１５】更に、コントロールユニット12は、図３の
フローチャートに示すようにして、前記第２酸素センサ
17の出力に基づき三元触媒10の劣化を診断する機能（触
媒劣化診断手段としての機能）を有しており、以下に図
３のフローチャートに従って前記診断機能について詳細
に説明する。図３のフローチャートにおいて、ます、ス
テップ１（図中ではＳ１としてある。以下同様）〜ステ
ップ３では、三元触媒10における酸素ストレージ効果が
収束し易い運転条件であるか否かを判別する。Further, the control unit 12 controls the second oxygen sensor as shown in the flow chart of FIG.
It has a function of diagnosing the deterioration of the three-way catalyst 10 based on the output of 17 (function as catalyst deterioration diagnosing means), and the diagnosis function will be described in detail below with reference to the flowchart of FIG. In the flowchart of FIG. 3, first, in step 1 (indicated as S1 in the figure; the same applies hereinafter) to step 3, it is determined whether or not the operating condition is such that the oxygen storage effect in the three-way catalyst 10 easily converges.
【００１６】即ち、本実施例では、三元触媒10の下流側
に設けられた第２酸素センサ17の出力に基づいて触媒劣
化の診断を行うから、かかる第２酸素センサ17の出力
が、触媒10の酸素ストレージ量の変動に影響を受ける
と、誤診断の原因となる。そこで、酸素ストレージ効果
の収束し易い運転条件で触媒劣化を診断させるようにし
ているものである。That is, in the present embodiment, the catalyst deterioration is diagnosed based on the output of the second oxygen sensor 17 provided on the downstream side of the three-way catalyst 10, so that the output of the second oxygen sensor 17 is the catalyst. Affected by fluctuations in oxygen storage capacity of 10, it causes a misdiagnosis. Therefore, the catalyst deterioration is diagnosed under the operating condition where the oxygen storage effect is easily converged.
【００１７】具体的には、車速ＶＳＰ，機関回転速度Ｎ
ｅ，基本噴射パルス幅Ｔｐ（機関負荷代表値）がそれぞ
れ所定範囲内であることを、ステップ１〜ステップ３で
確認する。そして、前記車速，回転，負荷の条件が成立
しているときには、ステップ４へ進み、所定の希薄空燃
比を目標空燃比とする空燃比フィードバック制御が行わ
れているか否かを判別する。これは、機関吸入混合気の
空燃比が所定の目標希薄空燃比に制御されることによっ
て、触媒10上流側における酸素濃度が所期値になってい
ることを、診断条件とするものである。Specifically, the vehicle speed VSP and the engine speed N
e, Steps 1 to 3 confirm that the basic injection pulse width Tp (representative value of engine load) is within a predetermined range. When the vehicle speed, rotation, and load conditions are satisfied, the routine proceeds to step 4, where it is determined whether or not the air-fuel ratio feedback control with a predetermined lean air-fuel ratio as the target air-fuel ratio is being performed. This is because the air-fuel ratio of the engine intake air-fuel mixture is controlled to a predetermined target lean air-fuel ratio, so that the oxygen concentration on the upstream side of the catalyst 10 has a desired value as a diagnostic condition.
【００１８】希薄燃焼フィードバック制御時であるとき
には、更に、ステップ５へ進み、第２酸素センサ17の出
力をモニタする。ここで、第２酸素センサ17の出力は、
空燃比フィードバック制御の影響を受けて周期変動する
から、次のステップ６では、第２酸素センサ17の出力を
平均化することで、出力中心値ＶA を求める。一方、ス
テップ７では、前記所定の希薄空燃比で燃焼させている
ときに、触媒10の非劣化状態で期待される第２酸素セン
サ17の出力Ｖ0 （基準値）を、機関運転条件（機関負
荷，機関回転速度）に応じて設定する。When the lean burn feedback control is being performed, the routine further proceeds to step 5, where the output of the second oxygen sensor 17 is monitored. Here, the output of the second oxygen sensor 17 is
Since the period fluctuates under the influence of the air-fuel ratio feedback control, in the next step 6, the output center value V A is obtained by averaging the output of the second oxygen sensor 17. On the other hand, in step 7, the output V 0 (reference value) of the second oxygen sensor 17 expected in the non-deteriorated state of the catalyst 10 during combustion at the predetermined lean air-fuel ratio is set to the engine operating condition (engine Set according to the load and engine speed).
【００１９】そして、ステップ８では、前記基準出力Ｖ
0 と、実際のセンサ出力ＶA との偏差ΔＶA を算出する
（図４参照）。次いで、ステップ９では、機関運転条件
（機関負荷，機関回転速度）に応じて設定される閾値Ｘ
と前記算出した偏差ΔＶA とを比較し、閾値Ｘを越える
偏差が生じている場合に、三元触媒10の劣化によって触
媒下流側の酸素濃度が非劣化時に比べて減っているもの
と見做し、ステップ10で触媒劣化の診断結果をランプ等
によって警告する。Then, in step 8, the reference output V
The deviation ΔV A between 0 and the actual sensor output V A is calculated (see FIG. 4). Next, at step 9, a threshold value X set according to the engine operating conditions (engine load, engine speed)
The calculated by comparing the deviation [Delta] V A, when the deviation exceeds the threshold value X has occurred, deemed to oxygen concentration downstream of the catalyst has decreased in comparison with the time of non-degraded by the deterioration of the catalytic converter 10 and Then, in step 10, the diagnosis result of catalyst deterioration is warned by a lamp or the like.
【００２０】即ち、三元触媒10の劣化が発生すると、酸
化・還元の反応が低下することにより、触媒10上流側に
おける酸素濃度が同じ（目標希薄空燃比に相当する濃
度）でも前記触媒作用の低下により触媒10下流側におけ
る酸素濃度に変化を来すことになる。そこで、目標希薄
空燃比に制御されていることを条件とすることで、触媒
10上流側の酸素濃度を規定し、このときの触媒10下流側
における酸素濃度が、触媒の非劣化状態で期待される出
力を示すか否かによって、触媒劣化による触媒10下流側
酸素濃度の変化を検知できるようにしたものである。That is, when the deterioration of the three-way catalyst 10 occurs, the oxidation / reduction reaction decreases, so that even if the oxygen concentration on the upstream side of the catalyst 10 is the same (concentration corresponding to the target lean air-fuel ratio), the catalytic action The decrease causes a change in the oxygen concentration on the downstream side of the catalyst 10. Therefore, the catalyst is controlled by the condition that it is controlled to the target lean air-fuel ratio.
10 The oxygen concentration on the upstream side is regulated, and depending on whether or not the oxygen concentration on the downstream side of the catalyst 10 at this time shows the expected output in the non-deteriorated state of the catalyst, the change in the oxygen concentration on the downstream side of the catalyst 10 due to catalyst deterioration It is made possible to detect.
【００２１】従って、本実施例のように希薄燃焼状態で
あっても必要充分な精度で触媒劣化を診断できる。尚、
上記実施例では、空燃比フィードバック制御を触媒10の
上流側に設けた第１酸素センサ16を用いて行わせるよう
にしたが、空燃比フィードバック制御に用いる空燃比検
出手段を前記第１酸素センサ16に限定するものではな
く、公知の種々の空燃比検出手段を用いることができ
る。Therefore, the catalyst deterioration can be diagnosed with necessary and sufficient accuracy even in the lean burn state as in this embodiment. still,
In the above embodiment, the air-fuel ratio feedback control is performed by using the first oxygen sensor 16 provided on the upstream side of the catalyst 10. However, the air-fuel ratio detecting means used for the air-fuel ratio feedback control is the first oxygen sensor 16 described above. However, various known air-fuel ratio detecting means can be used.
【００２２】[0022]
【発明の効果】以上説明したように本発明によると、触
媒下流側の酸素濃度の触媒劣化による変化を捉えて触媒
の劣化診断を行うから、希薄燃焼状態であっても触媒劣
化を精度良く診断できるようになり、触媒劣化診断装置
の信頼性を高めることができるという効果がある。As described above, according to the present invention, the deterioration of the catalyst is diagnosed by catching the change in the oxygen concentration on the downstream side of the catalyst due to the catalyst deterioration. Therefore, the catalyst deterioration can be accurately diagnosed even in the lean combustion state. As a result, it is possible to improve the reliability of the catalyst deterioration diagnosis device.
【図１】本発明の構成を示すブロック図。FIG. 1 is a block diagram showing a configuration of the present invention.
【図２】本発明の一実施例を示すシステム概略図。FIG. 2 is a system schematic diagram showing an embodiment of the present invention.
【図３】実施例における診断制御を示すフローチャー
ト。FIG. 3 is a flowchart showing diagnostic control in the embodiment.
【図４】実施例の酸素センサの出力特性を示す線図。FIG. 4 is a diagram showing the output characteristics of the oxygen sensor of the embodiment.
【符号の説明】 １ 機関 ６ 燃料噴射弁 10 三元触媒（排気浄化触媒） 12 コントロールユニット 13 エアフローメータ 14 クランク角センサ 16 第１酸素センサ 17 第２酸素センサ[Description of symbols] 1 engine 6 fuel injection valve 10 three-way catalyst (exhaust gas purification catalyst) 12 control unit 13 air flow meter 14 crank angle sensor 16 first oxygen sensor 17 second oxygen sensor
Claims (1)
と、 機関吸入混合気の空燃比を目標空燃比にフィードバック
制御する空燃比フィードバック制御手段と、 を備えて構成された内燃機関において、 前記排気浄化触媒の下流側に設けられ、排気中の酸素濃
度を広域に検出する酸素センサと、 前記空燃比フィードバック制御手段による空燃比フィー
ドバック制御時における前記酸素センサの出力値と前記
目標空燃比に対応する基準値との偏差に基づいて前記排
気浄化触媒の劣化を診断する触媒劣化診断手段と、 を含んで構成されることを特徴とする内燃機関の触媒劣
化診断装置。1. An internal combustion engine comprising: an exhaust purification catalyst provided in an exhaust passage of an engine; and an air-fuel ratio feedback control means for feedback-controlling an air-fuel ratio of an engine intake air-fuel mixture to a target air-fuel ratio, An oxygen sensor which is provided on the downstream side of the exhaust purification catalyst and which detects the oxygen concentration in the exhaust gas in a wide range, and an output value of the oxygen sensor during the air-fuel ratio feedback control by the air-fuel ratio feedback control means and the target air-fuel ratio A catalyst deterioration diagnosing device for an internal combustion engine, comprising: a catalyst deterioration diagnosing means for diagnosing deterioration of the exhaust purification catalyst based on a deviation from a corresponding reference value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5255943A JPH07109918A (en) | 1993-10-13 | 1993-10-13 | Catalysis degradation diagnosing device for internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5255943A JPH07109918A (en) | 1993-10-13 | 1993-10-13 | Catalysis degradation diagnosing device for internal combustion engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07109918A true JPH07109918A (en) | 1995-04-25 |
Family
ID=17285736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5255943A Pending JPH07109918A (en) | 1993-10-13 | 1993-10-13 | Catalysis degradation diagnosing device for internal combustion engine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07109918A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100381238B1 (en) * | 2000-11-09 | 2003-04-26 | 기아자동차주식회사 | Method for diagnosing a catalyst of an exhaust system for a motor vehicle |
| US20160097313A1 (en) * | 2014-10-01 | 2016-04-07 | Doosan Infracore Co., Ltd. | Engine control method for maintaining performance of oxidation catalyst |
| JP2018145943A (en) * | 2017-03-08 | 2018-09-20 | 株式会社デンソー | Engine control device |
-
1993
- 1993-10-13 JP JP5255943A patent/JPH07109918A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100381238B1 (en) * | 2000-11-09 | 2003-04-26 | 기아자동차주식회사 | Method for diagnosing a catalyst of an exhaust system for a motor vehicle |
| US20160097313A1 (en) * | 2014-10-01 | 2016-04-07 | Doosan Infracore Co., Ltd. | Engine control method for maintaining performance of oxidation catalyst |
| CN105484885A (en) * | 2014-10-01 | 2016-04-13 | 斗山英维高株式会社 | Engine control method for maintaining performance of oxidation catalyst |
| US9599002B2 (en) * | 2014-10-01 | 2017-03-21 | Doosan Infracore Co., Ltd. | Engine control method for maintaining performance of oxidation catalyst |
| JP2018145943A (en) * | 2017-03-08 | 2018-09-20 | 株式会社デンソー | Engine control device |
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