JP3013266B2 - Apparatus for detecting catalyst deterioration in exhaust gas purification apparatus and method for detecting catalyst deterioration - Google Patents
Apparatus for detecting catalyst deterioration in exhaust gas purification apparatus and method for detecting catalyst deteriorationInfo
- Publication number
- JP3013266B2 JP3013266B2 JP3160298A JP16029891A JP3013266B2 JP 3013266 B2 JP3013266 B2 JP 3013266B2 JP 3160298 A JP3160298 A JP 3160298A JP 16029891 A JP16029891 A JP 16029891A JP 3013266 B2 JP3013266 B2 JP 3013266B2
- Authority
- JP
- Japan
- Prior art keywords
- oxygen sensor
- deterioration
- way catalyst
- output
- catalyst
- 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 - Fee Related
Links
- 239000003054 catalyst Substances 0.000 title claims description 93
- 230000006866 deterioration Effects 0.000 title claims description 61
- 238000000034 method Methods 0.000 title claims description 18
- 238000000746 purification Methods 0.000 title claims description 14
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 77
- 239000001301 oxygen Substances 0.000 claims description 77
- 229910052760 oxygen Inorganic materials 0.000 claims description 77
- 239000007789 gas Substances 0.000 claims description 33
- 239000000446 fuel Substances 0.000 claims description 32
- 238000002485 combustion reaction Methods 0.000 claims description 13
- 238000011144 upstream manufacturing Methods 0.000 claims description 12
- 238000001514 detection method Methods 0.000 claims description 5
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 22
- 230000000694 effects Effects 0.000 description 7
- 230000015556 catabolic process Effects 0.000 description 3
- 238000006731 degradation reaction Methods 0.000 description 3
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 description 2
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- NLOAOXIUYAGBGO-UHFFFAOYSA-N C.[O] Chemical compound C.[O] NLOAOXIUYAGBGO-UHFFFAOYSA-N 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Exhaust Gas After Treatment (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、空燃比を調整する調整
装置と、内燃機関の排気側に三元触媒を備えた排ガス浄
化装置において、触媒劣化検出装置及びその触媒劣化検
出方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adjusting device for adjusting an air-fuel ratio, an exhaust gas purifying device having a three-way catalyst on the exhaust side of an internal combustion engine, and a catalyst deterioration detecting device and a method for detecting the catalyst deterioration. is there.
【０００２】[0002]
【従来の技術】本出願人は、空燃比を調整する調整装置
と、内燃機関の排気側に三元触媒とを備えた排ガス浄化
装置において、三元触媒の前流側と内燃機関の排気側と
の間にメタン活性の第１酸素センサを設け、三元触媒の
後流側にメタン不活性またはメタン低活性の第２酸素セ
ンサを設け、第１酸素センサと第２酸素センサからの出
力信号により調整装置を制御する制御装置を設けた排ガ
ス浄化装置を先に提案した。2. Description of the Related Art The present applicant discloses an exhaust gas purifying apparatus having an adjusting device for adjusting an air-fuel ratio and a three-way catalyst on the exhaust side of an internal combustion engine. And a methane-inactive or methane-low-active second oxygen sensor is provided downstream of the three-way catalyst, and output signals from the first and second oxygen sensors are provided. An exhaust gas purifying device provided with a control device for controlling the adjusting device according to the above was proposed earlier.
【０００３】この排ガス浄化装置は、第２酸素センサに
よって三元触媒の最適浄化領域を検出し、第１酸素セン
サの空燃比の制御点をこの検出した最適浄化領域内に移
動させ、この移動した空燃比の制御点で制御装置が調整
装置を制御することにより、空燃比制御を行うものであ
る。[0003] In this exhaust gas purifying apparatus, the optimum purification region of the three-way catalyst is detected by the second oxygen sensor, and the control point of the air-fuel ratio of the first oxygen sensor is moved into the detected optimal purification region. The control device controls the adjusting device at the control point of the air-fuel ratio to perform the air-fuel ratio control.
【０００４】これにより、三元触媒の初期的なメタン活
性の低下による最適浄化領域の移動の際に、この移動と
共に、第１酸素センサの空燃比制御点が移動するため、
常に最適な空燃比制御を行うことができる。[0004] When the three-way catalyst moves in the optimum purification region due to the initial decrease in methane activity, the air-fuel ratio control point of the first oxygen sensor moves together with this movement.
Optimal air-fuel ratio control can always be performed.
【０００５】ところで、このような排ガス浄化装置に使
用されている三元触媒が劣化した場合の検出方法として
は、従来より下記のような方法がある。By the way, as a method of detecting when the three-way catalyst used in such an exhaust gas purifying apparatus has deteriorated, the following method has conventionally been used.
【０００６】第１の方法としては、触媒の前後に温度セ
ンサを配し、触媒の前後の温度差を測定することによっ
て触媒の劣化を判断するものである。As a first method, a temperature sensor is disposed before and after the catalyst, and deterioration of the catalyst is determined by measuring a temperature difference between before and after the catalyst.
【０００７】この方法であると、触媒が新しい時には排
ガス中に含まれる未燃成分が触媒上で燃焼し、触媒前の
排ガスの温度よりも触媒後の排ガスの温度が上昇するた
め、触媒後の排ガスの温度が高くなる。According to this method, when the catalyst is new, unburned components contained in the exhaust gas burn on the catalyst, and the temperature of the exhaust gas after the catalyst is higher than the temperature of the exhaust gas before the catalyst. The temperature of the exhaust gas increases.
【０００８】ところが、触媒が劣化すると、温度上昇が
なくなり、触媒後の排ガス温度が低くなる。これによ
り、触媒の劣化を検出する。However, when the catalyst is deteriorated, the temperature does not rise, and the temperature of the exhaust gas after the catalyst decreases. Thereby, the deterioration of the catalyst is detected.
【０００９】第２の方法としては、空燃比を１Ｈｚ程度
の周期で振動させ、触媒の後流側に酸素センサを配し、
触媒の劣化を判断するものである。As a second method, the air-fuel ratio is vibrated at a cycle of about 1 Hz, and an oxygen sensor is arranged on the downstream side of the catalyst.
This is for determining the deterioration of the catalyst.
【００１０】この第２の方法であると、新しい触媒で
は、触媒の前流側の空燃比が１Ｈｚ程度の周期で変動し
ても、触媒の後流側の酸素センサの出力は変動しない。According to the second method, in the case of a new catalyst, even if the air-fuel ratio on the upstream side of the catalyst fluctuates at a cycle of about 1 Hz, the output of the oxygen sensor on the downstream side of the catalyst does not fluctuate.
【００１１】ところが、劣化した触媒では、触媒の前流
側の空燃比が１Ｈｚ程度の周期で変動した場合には、触
媒の前流側の空燃比の変動と同じ周波数（１Ｈｚ）で触
媒の後流側の酸素センサの出力が変動する。However, in the case of the deteriorated catalyst, when the air-fuel ratio on the upstream side of the catalyst fluctuates at a cycle of about 1 Hz, the downstream side of the catalyst has the same frequency (1 Hz) as the fluctuation of the air-fuel ratio on the upstream side of the catalyst. The output of the downstream oxygen sensor fluctuates.
【００１２】すなわち、触媒の後流側の酸素センサの出
力変動を監視することによって触媒の劣化を判断してい
る。That is, the deterioration of the catalyst is determined by monitoring the output fluctuation of the oxygen sensor on the downstream side of the catalyst.
【００１３】[0013]
【発明が解決しようとする課題】上記第１の方法の問題
点としては、劣化検出が安定して行われないことにな
る。すなわち、触媒の保温の状態や、負荷変動による排
ガス温度の変動などで検出が不安定になることである。As a problem of the first method, deterioration detection is not performed stably. That is, detection becomes unstable due to the state of keeping the temperature of the catalyst or fluctuation of exhaust gas temperature due to load fluctuation.
【００１４】第２の方法の問題点としては、この方法の
劣化検出原理が、酸素保持機能のある触媒中のセリアの
劣化を検出するものとなっている。触媒の活性は、ロジ
ウム成分，白金成分によるところが大きく、セリアの劣
化が触媒の活性と相関していない場合には、間違った判
断を行うこととなる。また、この方法は触媒の前流側の
空燃比を強制的に振動させることが必要であり、空燃比
を振動させる制御をしていないシステムには適応できな
いという問題がある。As a problem of the second method, the deterioration detection principle of this method detects deterioration of ceria in a catalyst having an oxygen retention function. The activity of the catalyst largely depends on the rhodium component and the platinum component. If the deterioration of ceria does not correlate with the activity of the catalyst, an incorrect judgment is made. Further, this method needs to forcibly vibrate the air-fuel ratio on the upstream side of the catalyst, and has a problem that it cannot be applied to a system that does not control the air-fuel ratio to vibrate.
【００１５】[0015]
【発明の目的】そこで本発明は、三元触媒の前流側と内
燃機関の排気側との間にメタン活性の第１センサを設
け、三元触媒の後流側にメタン活性またはメタン低活性
の第２センサを設け、第１センサと第２センサの出力信
号により、空燃比を調整する調整装置を制御する制御装
置を設けた排ガス浄化装置において、容易に三元触媒の
劣化を検出できる装置及び方法を提供するものである。SUMMARY OF THE INVENTION Accordingly, the present invention provides a first sensor for methane activity between the upstream side of a three-way catalyst and the exhaust side of an internal combustion engine. In the exhaust gas purifying apparatus provided with the second sensor and the control device for controlling the adjusting device for adjusting the air-fuel ratio based on the output signals of the first sensor and the second sensor, the deterioration of the three-way catalyst can be easily detected. And a method.
【００１６】[0016]
【課題を解決するための手段】請求項１の排ガス浄化装
置の触媒劣化検出装置は、空燃比を調整する調整装置
と、内燃機関の排気側に設けた三元触媒と、内燃機関の
排気側と三元触媒の前流側との間に設けた第１酸素セン
サと、三元触媒の後流側に設けたメタン不活性又はメタ
ン低活性の第２酸素センサと、第１酸素センサと第２酸
素センサからの出力信号により調整装置を制御する制御
装置とを備えた排ガス浄化装置において、三元触媒の劣
化状態時の第１酸素センサの出力信号の出力値を劣化基
準値として記憶する記憶手段と、記憶手段の劣化基準値
と第１酸素センサの出力信号の出力値を比較し、出力信
号の出力値が劣化基準値を越えた場合に報知信号を出力
する比較手段と、報知信号が入力した場合に三元触媒の
劣化を報知する報知手段とよりなるものである。According to a first aspect of the present invention, there is provided a catalyst deterioration detecting device for an exhaust gas purifying device, comprising: an adjusting device for adjusting an air-fuel ratio; a three-way catalyst provided on the exhaust side of the internal combustion engine; A first oxygen sensor provided between the three-way catalyst and the upstream side of the three-way catalyst; a methane-inactive or methane-low active second oxygen sensor provided downstream of the three-way catalyst; (2) In an exhaust gas purifying apparatus provided with a control device for controlling an adjusting device based on an output signal from an oxygen sensor, a memory for storing an output value of an output signal of a first oxygen sensor when a three-way catalyst is in a deteriorated state as a deterioration reference value. Means for comparing the deterioration reference value of the storage means with the output value of the output signal of the first oxygen sensor, and outputting a notification signal when the output value of the output signal exceeds the deterioration reference value; Notification of three-way catalyst deterioration when input It is intended to be more a stage.
【００１７】請求項２の排ガス浄化装置の触媒劣化検出
方法は、空燃比を調整する調整装置と、内燃機関の排気
側に設けた三元触媒と、内燃機関の排気側と三元触媒の
前流側との間に設けた第１酸素センサと、三元触媒の後
流側に設けたメタン不活性又はメタン低活性の第２酸素
センサと、第１酸素センサと第２酸素センサからの出力
信号により調整装置を制御する制御装置とを備えた排ガ
ス浄化装置において、第１酸素センサの出力信号の出力
値と劣化基準値を比較し、出力信号の出力値が劣化基準
値を越えた場合に報知手段が三元触媒の劣化を報知する
ものである。According to a second aspect of the present invention, there is provided a method for detecting catalyst deterioration in an exhaust gas purifying apparatus, comprising: an adjusting device for adjusting an air-fuel ratio; a three-way catalyst provided on the exhaust side of the internal combustion engine; A first oxygen sensor provided between the upstream side and the downstream side; a methane-inactive or methane low-active second side oxygen sensor provided downstream of the three-way catalyst; and outputs from the first and second oxygen sensors. In an exhaust gas purifying apparatus having a control device for controlling an adjusting device by a signal, an output value of an output signal of a first oxygen sensor is compared with a deterioration reference value, and when an output value of the output signal exceeds the deterioration reference value, The notification means notifies the deterioration of the three-way catalyst.
【００１８】[0018]
【作 用】請求項１の排ガス浄化装置の触媒劣化検出装
置であると、比較手段が、第１酸素センサの出力信号の
出力値と記憶手段が記憶している劣化基準値を比較し、
出力値が劣化基準値を超えた場合には、報知信号を報知
手段に出力する。報知手段は報知信号が入力すると、三
元触媒が劣化したことを報知する。The comparing means compares the output value of the output signal of the first oxygen sensor with the deterioration reference value stored in the storage means.
If the output value exceeds the deterioration reference value, the control unit outputs a notification signal to the notification unit. When the notification signal is input, the notification unit notifies that the three-way catalyst has deteriorated.
【００１９】請求項２の排ガス浄化装置の触媒劣化検出
方法であると、第１酸素センサの出力信号の出力値と劣
化基準値を比較し、出力信号の出力値が劣化基準値を超
えた場合に報知手段が三元触媒の劣化を報知する。According to a second aspect of the present invention, the output value of the output signal of the first oxygen sensor is compared with a degradation reference value, and the output value of the output signal exceeds the degradation reference value. The notification means notifies the deterioration of the three-way catalyst.
【００２０】[0020]
【実施例】以下、本発明の一実施例を図面に基づいて説
明していく。An embodiment of the present invention will be described below with reference to the drawings.
【００２１】図１は本実施例の空燃比制御システム１０
のブロック図である。FIG. 1 shows an air-fuel ratio control system 10 according to this embodiment.
It is a block diagram of.
【００２２】符号１２は燃料供給管である。この燃料供
給管１２から都市ガス１３Ａが供給され、空気供給管１
４から空気が供給される。Reference numeral 12 denotes a fuel supply pipe. The city gas 13A is supplied from the fuel supply pipe 12, and the air supply pipe 1
Air is supplied from 4.
【００２３】符号１６はスロットルである。Reference numeral 16 is a throttle.
【００２４】符号１８はバイパス弁であって、このバイ
パス弁１８はモジュールモータによって動作する。Reference numeral 18 denotes a bypass valve, which is operated by a module motor.
【００２５】符号２０はガスエンジンである。Reference numeral 20 denotes a gas engine.
【００２６】符号２２はガスエンジンの排気側に設けら
れた三元触媒である。Reference numeral 22 denotes a three-way catalyst provided on the exhaust side of the gas engine.
【００２７】符号２４は、ガスエンジン２０の排気側と
三元触媒の前流側との間に設けられた第１酸素センサで
ある。この第１酸素センサ２４は、メタン活性の酸素セ
ンサである。Reference numeral 24 denotes a first oxygen sensor provided between the exhaust side of the gas engine 20 and the upstream side of the three-way catalyst. The first oxygen sensor 24 is a methane active oxygen sensor.
【００２８】符号２６は三元触媒の後流側に設けられた
第２酸素センサである。この第２酸素センサ２６は、メ
タン不活性もしくはメタン低活性型酸素センサである。
このようなメタン不活性もしくはメタン低活性型酸素セ
ンサとしては、例えば、ペロブスカイト型複合酸化物を
用いた酸素センサが挙げられる。この第２酸素センサ２
６の急変点は、メタン不活性特性により、メタン活性が
落ちた三元触媒２２であっても、その最適浄化領域と常
にほぼ一致する。Reference numeral 26 denotes a second oxygen sensor provided on the downstream side of the three-way catalyst. The second oxygen sensor 26 is a methane inert or methane low active oxygen sensor.
An example of such a methane inert or low methane oxygen sensor is an oxygen sensor using a perovskite-type composite oxide. This second oxygen sensor 2
The sudden change point of 6 almost always coincides with the optimum purification region even for the three-way catalyst 22 having reduced methane activity due to the methane inerting characteristic.
【００２９】符号２８は、第１酸素センサ２４及び第２
酸素センサ２６からの出力電圧に応じて、バイパス弁１
８のモジュールモータを動作する制御装置である。ま
た、この制御装置２８は、メモリを有しており、三元触
媒の劣化状態時に出力される第１酸素センサ２４からの
出力電圧値を劣化基準値として記憶している。そして、
この劣化基準値と第１酸素センサ２４からの出力電圧を
比較し、出力電圧が劣化基準値を超えた場合には、報知
信号を出力する。Reference numeral 28 denotes the first oxygen sensor 24 and the second oxygen sensor 24.
According to the output voltage from the oxygen sensor 26, the bypass valve 1
8 is a control device for operating the module motor of FIG. Further, the control device 28 has a memory, and stores, as a deterioration reference value, an output voltage value from the first oxygen sensor 24 output when the three-way catalyst is in a deteriorated state. And
The deterioration reference value is compared with the output voltage from the first oxygen sensor 24, and when the output voltage exceeds the deterioration reference value, a notification signal is output.
【００３０】符号３０は、制御装置２８に接続された報
知装置である。この報知装置３０は制御装置２８から報
知信号が入力すると、劣化を知らせるためのランプが点
灯する。Reference numeral 30 denotes a notification device connected to the control device 28. When the notification signal is input from the control device 28 to the notification device 30, a lamp for notifying the deterioration is turned on.
【００３１】次に上記構成の空燃比制御システム１０に
おける動作状態を説明する。Next, an operation state of the air-fuel ratio control system 10 having the above configuration will be described.
【００３２】図２のグラフはメタン活性の低下した三元
触媒２２の排ガス中の各ガス濃度と、第１酸素センサ２
４及び第２センサ２６の特性を示している。FIG. 2 is a graph showing the concentration of each gas in the exhaust gas of the three-way catalyst 22 having reduced methane activity and the first oxygen sensor 2.
4 shows the characteristics of the fourth and second sensors 26.
【００３３】上記構成の空燃比制御システム１０である
と、第２酸素センサ２６の急変点と、三元触媒２２の最
適浄化領域とが常に一致しているため、この第２酸素セ
ンサ２６の急変点を制御装置２８が検出する。In the air-fuel ratio control system 10 having the above-described configuration, the sudden change point of the second oxygen sensor 26 always coincides with the optimum purification region of the three-way catalyst 22. The controller 28 detects the point.
【００３４】制御装置２８は第１酸素センサ２４の空燃
比の制御点（制御電圧）を第２酸素センサ２６の急変点
に合せる。図２においては、制御電圧をＡ点からＢ点に
移動させる。これにより、三元触媒２２の劣化した状態
の最適浄化領域に合せることができる。The controller 28 adjusts the control point (control voltage) of the air-fuel ratio of the first oxygen sensor 24 to the sudden change point of the second oxygen sensor 26. In FIG. 2, the control voltage is moved from point A to point B. Thus, the three-way catalyst 22 can be adjusted to the optimum purification region in a deteriorated state.
【００３５】すなわち、第２酸素センサを利用する際に
は、第２酸素センサ２６の出力電圧がある一定値を超え
たかもしくは超えないかでリーン側かリッチ側かを判断
する。そしてこの第２酸素センサ２６を利用することに
より、測定した排ガスがリーン側かリッチ側かを判断
し、第１酸素センサ２４の空燃比の制御点を三元触媒２
２の最適浄化領域に追従させることができる。That is, when using the second oxygen sensor, it is determined whether the output voltage of the second oxygen sensor 26 is lean or rich depending on whether or not the output voltage exceeds a certain value. By using the second oxygen sensor 26, it is determined whether the measured exhaust gas is lean or rich, and the control point of the air-fuel ratio of the first oxygen sensor 24 is
2 can follow the optimum purification region.
【００３６】これにより、三元触媒２２の劣化状態に関
わらず、長期的に安定な浄化性能を得ることができる。Thus, regardless of the state of deterioration of the three-way catalyst 22, a long-term stable purification performance can be obtained.
【００３７】ところで、三元触媒２２の劣化が更に進
み、第２酸素センサ２６の急変点が、更に移動したとす
る。すると、第１酸素センサの最適浄化領域は点Ｃにシ
フトする。この場合に制御装置２８に記憶された劣化基
準値Ｘ点を超える。したがって、制御装置２８は、三元
触媒２２が基準よりも劣化したと判断し、報知信号を報
知装置３０に出力する。報知装置３０では報知信号が入
力し、劣化を知らせるランプを点灯させる。By the way, it is assumed that the deterioration of the three-way catalyst 22 further progresses, and the sudden change point of the second oxygen sensor 26 further moves. Then, the optimum purification region of the first oxygen sensor shifts to the point C. In this case, it exceeds the deterioration reference value X point stored in the control device 28. Therefore, control device 28 determines that three-way catalyst 22 has deteriorated below the reference, and outputs a notification signal to notification device 30. The notification signal is input to the notification device 30, and a lamp for notifying the deterioration is turned on.
【００３８】これにより、三元触媒２２の劣化状態を一
目で判別することができる。Thus, the deterioration state of the three-way catalyst 22 can be determined at a glance.
【００３９】本出願人は、各種劣化状態の三元触媒２２
の浄化性能と第１酸素センサ２４の劣化基準値の対比実
験を行った。ガスエンジン２０は５０ｋｗタイプガスエ
ンジンであり、三元触媒２２の後流側の第２酸素センサ
２６にはメタン低活性センサを使用した。The present applicant has proposed a three-way catalyst 22 in various degraded states.
An experiment was conducted to compare the purification performance of the first oxygen sensor with the degradation reference value of the first oxygen sensor 24. The gas engine 20 was a 50 kW type gas engine, and a methane low activity sensor was used as the second oxygen sensor 26 on the downstream side of the three-way catalyst 22.
【００４０】測定方法は、制御装置２８として、ＥＣＵ
を用いて、第２酸素センサ２６の出力が０．６Ｖになる
ように、第２酸素センサ２４の劣化基準値Ｖｆを決め、
Ｖｆになるように空燃比制御用アクチュエータをコント
ロールして空燃比を一定に保った。劣化程度の異なる三
元触媒２２を用いて、第１酸素センサ２４の劣化基準値
Ｖｆを測定した。その測定した結果が表１のようになっ
た。The measuring method is as follows.
Is used to determine the deterioration reference value Vf of the second oxygen sensor 24 so that the output of the second oxygen sensor 26 becomes 0.6 V,
The air-fuel ratio was kept constant by controlling the air-fuel ratio control actuator to Vf. The deterioration reference value Vf of the first oxygen sensor 24 was measured using the three-way catalysts 22 having different degrees of deterioration. Table 1 shows the measurement results.
【００４１】[0041]
【表１】 [Table 1]
【００４２】表１から明らかなように、Ｖｆの値を新品
の状態の三元触媒２２のＶｆと比較すると、劣化検出が
明らかに行えることがわかった。As is apparent from Table 1, when the value of Vf is compared with the value of Vf of the three-way catalyst 22 in a new state, it is found that deterioration can be clearly detected.
【００４３】なお、本実施例では、報知装置３０として
ランプを点灯させたが、これに代えて、ブザ−を鳴らし
たり、ガスエンジンを自動的に停止させるようなもので
もよい。In this embodiment, a lamp is turned on as the notification device 30. Alternatively, a buzzer may be sounded or the gas engine may be automatically stopped.
【００４４】[0044]
【発明の効果】上記により、本発明の排ガス浄化装置の
触媒劣化検出装置及びその触媒劣化検出方法であると、
第１酸素センサの出力信号の出力値と、劣化基準値とを
比較して、出力信号の出力値が劣化基準値を超えた場合
に報知手段が劣化を報知するため、容易にその劣化状態
がわかると共に、浄化性能が極端に劣化する前に三元触
媒を交換することができ、ＮＯｘを大気中に排出するこ
とを未然に防止することができる。As described above, according to the catalyst deterioration detecting apparatus and the catalyst deterioration detecting method of the exhaust gas purifying apparatus of the present invention,
Since the output value of the output signal of the first oxygen sensor is compared with the deterioration reference value, and when the output value of the output signal exceeds the deterioration reference value, the notifying means notifies the deterioration. In addition, it is possible to replace the three-way catalyst before the purification performance is extremely deteriorated, and it is possible to prevent NOx from being discharged into the atmosphere.
【図面の簡単な説明】[Brief description of the drawings]
【図１】本実施例の空燃比制御システムのブロック図で
ある。FIG. 1 is a block diagram of an air-fuel ratio control system according to an embodiment.
【図２】第１酸素センサ及び第２酸素センサの出力電圧
及びガス濃度との関係を示したグラフである。FIG. 2 is a graph showing a relationship between an output voltage and a gas concentration of a first oxygen sensor and a second oxygen sensor.
１０……空燃比制御システム １２……燃料供給管 １４……空気供給管 １６……スロットル １８……バイパス弁 ２０……ガスエンジン ２２……三元触媒 ２４……第１酸素センサ ２６……第２酸素センサ ２８……制御装置 ３０……報知装置 10 air fuel ratio control system 12 fuel supply pipe 14 air supply pipe 16 throttle 18 bypass valve 20 gas engine 22 three-way catalyst 24 first oxygen sensor 26 first 2 Oxygen sensor 28 Control device 30 Notification device
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平３−74540（ＪＰ，Ａ) 特開 平３−151544（ＪＰ，Ａ) 特開 平４−298659（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) F02D 41/14 310 F01N 3/20 F02D 41/22 305 F02D 45/00 314 F02D 45/00 368 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-74540 (JP, A) JP-A-3-151544 (JP, A) JP-A-4-2988659 (JP, A) (58) Field (Int.Cl. 7 , DB name) F02D 41/14 310 F01N 3/20 F02D 41/22 305 F02D 45/00 314 F02D 45/00 368
Claims (4)
１酸素センサと、 三元触媒の後流側に設けたメタン不活性又はメタン低活
性の第２酸素センサと、第１酸素センサと第２酸素セン
サからの出力信号により調整装置を制御する制御装置と
を備えた排ガス浄化装置において、 三元触媒の劣化状態時の第１酸素センサの出力信号の出
力値を劣化基準値として記憶する記憶手段と、 記憶手段の劣化基準値と第１酸素センサの出力信号の出
力値を比較し、出力信号の出力値が劣化基準値を越えた
場合に報知信号を出力する比較手段と、 報知信号が入力した場合に三元触媒の劣化を報知する報
知手段とよりなることを特徴とする排ガス浄化装置の触
媒劣化検出装置。1. An adjusting device for adjusting an air-fuel ratio, a three-way catalyst provided on an exhaust side of an internal combustion engine, and a first oxygen sensor provided between an exhaust side of the internal combustion engine and a upstream side of the three-way catalyst. A methane-inactive or methane-low-active second oxygen sensor provided on the downstream side of the three-way catalyst; and a control device for controlling the adjusting device based on output signals from the first oxygen sensor and the second oxygen sensor. Storage means for storing an output value of the output signal of the first oxygen sensor when the three-way catalyst is in a deteriorated state as a deterioration reference value; and a storage means for storing the deterioration reference value of the storage means and the output signal of the first oxygen sensor. Comparing means for comparing output values and outputting a notification signal when the output value of the output signal exceeds a deterioration reference value, and notification means for notifying deterioration of the three-way catalyst when the notification signal is input. Detection of catalyst deterioration in exhaust gas purification equipment Location.
１酸素センサと、 三元触媒の後流側に設けたメタン不活性又はメタン低活
性の第２酸素センサと、第１酸素センサと第２酸素セン
サからの出力信号により調整装置を制御する制御装置と
を備えた排ガス浄化装置において、 第１酸素センサの出力信号の出力値と劣化基準値を比較
し、出力信号の出力値が劣化基準値を越えた場合に報知
手段が三元触媒の劣化を報知することを特徴とする排ガ
ス浄化装置の触媒劣化検出方法。2. An adjusting device for adjusting an air-fuel ratio, a three-way catalyst provided on the exhaust side of the internal combustion engine, and a first oxygen sensor provided between the exhaust side of the internal combustion engine and the upstream side of the three-way catalyst. A methane-inactive or methane-low-active second oxygen sensor provided on the downstream side of the three-way catalyst, and a control device for controlling the adjusting device based on output signals from the first oxygen sensor and the second oxygen sensor. Comparing the output value of the output signal of the first oxygen sensor with the deterioration reference value, and notifying the deterioration of the three-way catalyst when the output value of the output signal exceeds the deterioration reference value. A method for detecting catalyst deterioration in an exhaust gas purifying apparatus, comprising:
１酸素センサと、 三元触媒の後流側に設けたメタン不活性又はメタン低活
性の第２酸素センサと、第１酸素センサと第２酸素セン
サからの出力信号により調整装置を制御する制御装置と
を備えた排ガス浄化装置において、 三元触媒の劣化状態時の第１酸素センサの出力信号の出
力値を劣化基準値として記憶する記憶手段と、 記憶手段の劣化基準値と第１酸素センサの出力信号の出
力値を比較し、出力信号の出力値が劣化基準値を越えた
場合に報知信号を出力する比較手段と、 報知信号が入力した場合に三元触媒の劣化を報知する報
知手段とよりなることを特徴とする排ガス浄化装置の触
媒劣化検出装置。3. An adjusting device for adjusting an air-fuel ratio, a three-way catalyst provided on the exhaust side of the internal combustion engine, and a first oxygen sensor provided between the exhaust side of the internal combustion engine and the upstream side of the three-way catalyst. A methane-inactive or methane-low-active second oxygen sensor provided on the downstream side of the three-way catalyst, and a control device for controlling the adjusting device based on output signals from the first oxygen sensor and the second oxygen sensor. Storage means for storing the output value of the output signal of the first oxygen sensor when the three-way catalyst is in a deteriorated state as a deterioration reference value, wherein the storage means stores the deterioration reference value of the storage means and the output signal of the first oxygen sensor. Comparing means for comparing output values and outputting a notification signal when the output value of the output signal exceeds the deterioration reference value, and notification means for notifying deterioration of the three-way catalyst when the notification signal is input. Detection of catalyst deterioration in exhaust gas purification equipment Location.
１酸素センサと、 三元触媒の後流側に設けたメタン不活性又はメタン低活
性の第２酸素センサと、第１酸素センサと第２酸素セン
サからの出力信号により調整装置を制御する制御装置と
を備えた排ガス浄化装置において、 第１酸素センサの出力信号の出力値と劣化基準値を比較
し、出力信号の出力値が劣化基準値を越えた場合に報知
手段が三元触媒の劣化を報知することを特徴とする排ガ
ス浄化装置の触媒劣化検出方法。4. An adjusting device for adjusting an air-fuel ratio, a three-way catalyst provided on the exhaust side of the internal combustion engine, and a first oxygen sensor provided between the exhaust side of the internal combustion engine and the upstream side of the three-way catalyst. A methane-inactive or methane-low-active second oxygen sensor provided on the downstream side of the three-way catalyst, and a control device for controlling the adjusting device based on output signals from the first oxygen sensor and the second oxygen sensor. Comparing the output value of the output signal of the first oxygen sensor with the deterioration reference value, and notifying the deterioration of the three-way catalyst when the output value of the output signal exceeds the deterioration reference value. A method for detecting catalyst deterioration in an exhaust gas purifying apparatus, comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3160298A JP3013266B2 (en) | 1991-07-01 | 1991-07-01 | Apparatus for detecting catalyst deterioration in exhaust gas purification apparatus and method for detecting catalyst deterioration |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3160298A JP3013266B2 (en) | 1991-07-01 | 1991-07-01 | Apparatus for detecting catalyst deterioration in exhaust gas purification apparatus and method for detecting catalyst deterioration |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0510181A JPH0510181A (en) | 1993-01-19 |
| JP3013266B2 true JP3013266B2 (en) | 2000-02-28 |
Family
ID=15711946
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3160298A Expired - Fee Related JP3013266B2 (en) | 1991-07-01 | 1991-07-01 | Apparatus for detecting catalyst deterioration in exhaust gas purification apparatus and method for detecting catalyst deterioration |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3013266B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3101884B2 (en) | 1991-07-15 | 2000-10-23 | 大阪瓦斯株式会社 | Catalyst deterioration detection device for exhaust gas purification device |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3284844B2 (en) * | 1995-09-20 | 2002-05-20 | トヨタ自動車株式会社 | Catalyst deterioration detection device |
| DE69635917T2 (en) * | 1995-10-26 | 2006-10-19 | Toyota Jidosha Kabushiki Kaisha, Toyota | Detection device of catalyst deterioration of an internal combustion engine |
-
1991
- 1991-07-01 JP JP3160298A patent/JP3013266B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3101884B2 (en) | 1991-07-15 | 2000-10-23 | 大阪瓦斯株式会社 | Catalyst deterioration detection device for exhaust gas purification device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0510181A (en) | 1993-01-19 |
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