JP3467795B2 - Engine exhaust purification device - Google Patents
Engine exhaust purification deviceInfo
- Publication number
- JP3467795B2 JP3467795B2 JP05032193A JP5032193A JP3467795B2 JP 3467795 B2 JP3467795 B2 JP 3467795B2 JP 05032193 A JP05032193 A JP 05032193A JP 5032193 A JP5032193 A JP 5032193A JP 3467795 B2 JP3467795 B2 JP 3467795B2
- Authority
- JP
- Japan
- Prior art keywords
- exhaust gas
- temperature
- exhaust
- catalyst
- engine
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、エンジンの排気浄化装
置に関するものであり、特にリ−ンな空燃比に対応する
酸素濃度を有する排気に対して良好なＮＯX浄化特性を
有する触媒を排気系に備えたエンジンの排気浄化装置に
関する。
【０００２】
【従来の技術】自動車用エンジンにおいては、排気中に
含まれるＮＯX，ＨＣ，ＣＯのような有害成分を浄化す
るために、その排気系に触媒を備えている。一般の三元
触媒は、その排気浄化特性がエンジンの空燃比によって
大きく変化し、空燃比の大きいリ−ン側では、燃焼後も
排気中の酸素の量が多くなって、酸化作用が活発に、還
元作用が不活発になる。また、空燃比の小さいリッチ側
では、燃焼後も排気中の酸素の量が多くなって、還元作
用が活発に、酸化作用が不活発になる。そして、酸化と
還元とのバランスがとれる理論空燃比（λ＝１，Ａ／Ｆ
＝14.7）付近では三元触媒がもっとも有効に働くため、
三元触媒を用いる排気浄化装置を備えた自動車では、排
気中の酸素濃度を検出して、混合気を理論空燃比付近に
保つようにフィ−ドバック制御を行なっている。
【０００３】一方、自動車用エンジンにおいては、低燃
費化も要請されており、そのために、なるべくリ−ンな
混合気を燃焼させる（リ−ンバ−ン）ようにする努力が
なされているが、リ−ン側ではＨＣ，ＣＯは酸化除去で
きても、ＮＯXを還元除去することが困難になる。この
ため、リ−ンバ−ンエンジンの排気系に用いる排気ガス
除去用触媒として、例えば、特開平１−３１０７４２号
公報に開示されているような、Ｃｕなどの遷移金属がゼ
オライトにイオン交換担持されかつ貴金属がされた担持
触媒層が、耐火性担体上に設けられた、いわゆるＮＯX
触媒が提案されている。
【０００４】
【発明が解決しようとする課題】ところで、上記のよう
なＮＯX触媒は、例えばＡ／Ｆ＝22（λ＝1.5）程度のリ
−ンな空燃比に対応する排気中では、図４に実線Ｉで示
すように、ＨＣに対して冷間時においても良好な浄化特
性を有するが、理論空燃比付近では、破線IIで示すよう
に、冷間時の特性は劣悪であり、しかも、温間時におい
ても浄化率が低い。従って、エンジン始動直後の理論空
燃比に近い燃焼状態で多量に排出されるＨＣ（ＣＯ）を
浄化できないという問題があり、かつ温間時においても
ＨＣ浄化率の向上が望まれていた。
【０００５】一方、上記ＮＯX触媒は、三元触媒に比較
して良好なＮＯX浄化特性を有するものの、図５に示す
ように、最大ＮＯX浄化率を示す温度が空燃比がリ−ン
になる程、すなわち、排気中の酸素濃度が増大するのに
応じて低下し、かつ該最大ＮＯX浄化率も排気中の酸素
濃度の増大に伴って低下する特性を有するものである。
【０００６】上述の事情に鑑み、本発明は、ＮＯX触媒
を用いて所期のＮＯX浄化特性を保ちながら、特に冷間
時におけるＨＣ浄化特性を飛躍的に向上させたエンジン
の排気浄化装置を提供することを目的とする。
【０００７】
【課題を解決するための手段】本発明によるエンジンの
排気浄化装置は、エンジンの排気通路に配設され、排気
中の酸素濃度が高くなるほど且つ触媒入口排気温度が高
くなるほどＨＣ浄化率が高くなり、最大ＮＯｘ浄化率を
示す温度が排気中の酸素濃度の増大に応じて低下する特
性を有する触媒と、上記排気通路の上記触媒配設位置の
上流に２次エアを供給する２次エア供給手段と、上記排
気通路の上記触媒配設位置の上流にある排気を加熱する
ためのヒータと、上記触媒の入口排気温度を検出する排
気温度センサと、上記触媒に供給される排気中の酸素濃
度に関する値を検知するＯ 2 センサと、上記排気温度及
び酸素濃度に応じて上記２次エア供給手段及びヒータを
制御する制御手段とを備え、当該制御手段は、エンジン
の始動時に、排気温度が所定温度に上がるまでの間、上
記ヒータのみを作動させて排気を加熱する一方、排気温
度が上記所定温度に上がった後、上記２次エア供給手段
を制御して排気中の酸素濃度を上昇させるように構成さ
れていることを特徴とするものである。
【０００８】
【作用および効果】本発明によれば、排気通路の上記触
媒配設位置の上流にある排気を加熱するためのヒータ
と、排気通路の上記触媒配設位置の上流に２次エアを供
給する２次エア供給手段とがエンジンの排気系に設けら
れ、制御手段が、エンジンの始動時に、排気温度が所定
温度に上がるまでの間、上記ヒータのみを作動させる一
方、排気温度が上記所定温度に上がった後、上記２次エ
ア供給手段を制御して排気中の 酸素濃度を上昇させるた
めに、エンジン始動時に上記触媒の温度を上記ヒーター
により速やかに上昇させることができ、かつ上記２次エ
ア供給手段により排気中の酸素濃度を増大させることが
できるから、エンジン始動時における触媒のＨＣ浄化特
性を飛躍的に向上させることができる。
【０００９】
【実施例】以下、本発明の実施例について図面を参照し
ながら説明する。
【００１０】図１は、本発明によるエンジンの排気浄化
装置の構成を示す概略図である。図１において、排気通
路１に配設されているＮＯX触媒２の上流側には、排気
を加熱するための電気ヒ−タ３が配設され、この電気ヒ
−タ３の上流側に、排気通路１に２次エアを供給するた
めのエア通路４が接続されている。エア通路４にはエア
ポンプ５が連結されている。
【００１１】さらに、ＮＯX触媒２と電気ヒ−タ３との
間の排気通路１には、エンジン側の排気通路に設けられ
ている空燃比制御用の図示しないＯ2センサに加えて、
触媒２に供給される排気中の酸素濃度を検出するための
Ｏ2センサ６と、触媒２の入口の排気温度を検出するた
めの温度センサ７とが配設されている。８はコントロ−
ラで、このコントロ−ラ８は、Ｏ2センサ６および温度
センサ７の出力と、エンジン回転数センサ９およびエン
ジン水温センサ10の出力とに基づいて、電気ヒ−タ３お
よびエアポンプ５を以下に述べる態様で制御するように
なっている。
【００１２】すなわち、まず、前述した図５における酸
素濃度をパラメ−タとしたＮＯX浄化率を示す特性曲線
から、図２に示すように、ＮＯX浄化率の最大値が要求
最小浄化率（例えば68％）を満足し得る酸素濃度に対応
する空燃比と、その空燃比における最大ＮＯX浄化率を
示す温度（以下この温度をＴ0とする）を、例えばＡ／
Ｆ＝22（λ＝1.5）、温度220°Ｃとして求める。
【００１３】そして、エンジン始動時のような冷間時に
は、エンジン水温が規定温度（例えば80°Ｃ）に達する
まで、λ＝１になるようなエンジンの空燃比制御を実行
するとともに、エアポンプ５を停止させた状態で、電気
ヒ−タ３のみを作動させて排気を加熱し、排気温度を可
及的速やかに上昇させる。そして、排気温度が温度Ｔ0
（220°Ｃ）に達した時点で、エアポンプ５を作動させ
て２次エアを触媒２の上流側の排気通路１に導入し、触
媒２に供給される排気の酸素濃度をλ＝1.5に対応した
ものにする。従って、ＨＣ浄化率は、図２に示すよう
に、排気温度がＴ0に達するＡ点までは、破線で示すλ
＝１のときの特性曲線IIに沿って緩やかに上昇し、排気
温度がＴ0に達すると、一挙にほぼ垂直に上昇して、実
線で示すλ＝1.5のときの特性曲線Ｉ上のＢ点に達する
ことになる。したがって、エンジン始動時における触媒
のＨＣ浄化特性を飛躍的に向上させることができる。
【００１４】そして、それ以降は、排気温度がＴ0に保
たれるように、かつ排気中の酸素濃度がλ＝1.5に対応
する酸素濃度に保たれるように、電気ヒ−タ３およびエ
アポンプ５を制御することにより、ＮＯX浄化率につい
ては要求最小浄化率を満足させながら、ＨＣ浄化特性を
改善することができる。
【００１５】その場合に、冷間時およびアイドル時には
空燃比がλ＝１になるように燃料噴射量を制御するが、
通常走行時には例えばλ＝1.5となるように空燃比制御
を実行するリ−ンバ−ンエンジンにおいては、アイドル
時にのみ２次エアを排気通路１に導入し、通常走行時に
は２次エアの導入を停止すればよい。
【００１６】なお、本実施例では、温度センサ７が排気
通路１に設けられているが、触媒２に取り付けられて、
触媒２の温度を検出するものであってもよい。
【００１７】図３はコントロ−ラ８が実行する制御ル−
チンのフロ−チャ−トをしめす。
【００１８】まず、ステップＳ１でエンジンの始動と同
時に電気ヒ−タ３のみを作動させて排気を加熱する。次
にステップＳ２で、エンジン水温が規定温度に達したか
否か、すなわち冷間時か否かを判定し、冷間時であれ
ば、また冷間時でなくても、ステップＳ９でアイドル時
と判定された場合は、ステップＳ３で空燃比がλ＝１に
なるように燃料噴射量を制御する。
【００１９】次のステップＳ４では、排気温度がＴ0に
達しているか否かを調べ、Ｔ0に達していると判定され
たときには、ステップＳ５で電気ヒ−タ３をOFFにする
とともに、エアポンプ５を作動させて２次エアを触媒２
の上流側の排気通路１に導入し、触媒２に供給される排
気の酸素濃度をλ＝1.5に対応したものにする。そし
て、次のステップＳ６でエンジンがλ＝１となるような
空燃比制御を実行しているか否かを調べ、λ＝１であれ
ば、ステップＳ７へ進んで排気温度がＴ0に達している
か否かを調べ、達していなければ、ステップＳ８で電気
ヒ−タ３をONにして排気温度を上昇させ、ステップＳ４
へ戻るというフィ−ドバック制御を実行する。
【００２０】一方、アイドル時および冷間時を除いてλ
＝1.5程度のリ−ンバ−ンの空燃比制御を実行するエン
ジンにおいては、ステップＳ６およびＳ９の判定が「N
O」となるから、ステップＳ10へ進み、さらにステップ
Ｓ11へ進んで、エアポンプ５を停止させ、２次エアの導
入を停止する。そして、ステップＳ12で排気温度がＴ0
に達しているか否かを調べ、Ｔ0に達していると判定さ
れたときには、ステップＳ13で電気ヒ−タ３をONにす
る．次にステップＳ14で排気温度がＴ0に達しているか
否かを調べ、Ｔ0に達していると判定されたときには、
ステップＳ15で電気ヒ−タ３をOFFにして、ステップＳ1
2へ戻るというフィ−ドバック制御を実行する。なお、
２次エアの導入を停止すれば、排気温度の変化が小さく
なるので、ステップＳ12〜Ｓ15のフィ−ドバック制御の
実行を省略することも可能である。
【００２１】以上のような制御ル−チンを実行すること
により、エンジン始動時における触媒のＨＣ浄化特性を
飛躍的に向上させることができるとともに、走行時にお
けるＨＣおよびＮＯXに対する浄化特性も向上させるこ
とができる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for an engine, and particularly to an exhaust gas having an oxygen concentration corresponding to a lean air-fuel ratio. such an exhaust purification device of an engine having a catalyst in an exhaust system having a NO X purification characteristic. 2. Description of the Prior Art An engine for an automobile, NO X contained in the exhaust, HC, for purifying harmful components such as CO, and a catalyst to the exhaust system. The exhaust purification characteristics of a general three-way catalyst vary greatly depending on the air-fuel ratio of the engine. On the lean side where the air-fuel ratio is large, the amount of oxygen in the exhaust gas increases even after combustion, and the oxidizing action becomes active. , The reducing action becomes inactive. Further, on the rich side where the air-fuel ratio is small, the amount of oxygen in the exhaust gas becomes large even after combustion, so that the reducing action becomes active and the oxidizing action becomes inactive. Then, the stoichiometric air-fuel ratio (λ = 1, A / F
= 14.7), the three-way catalyst works most effectively.
In an automobile equipped with an exhaust gas purification device using a three-way catalyst, feedback control is performed so as to maintain the air-fuel mixture near the stoichiometric air-fuel ratio by detecting the oxygen concentration in the exhaust gas. [0003] On the other hand, there has been a demand for lower fuel consumption of automobile engines. For this purpose, efforts have been made to burn a lean mixture as much as possible (lean burn). Li - HC in emissions side, CO is also able to remove oxidation, it is difficult to reduce and remove NO X. For this reason, as an exhaust gas removing catalyst used in an exhaust system of a lean burn engine, for example, a transition metal such as Cu as disclosed in JP-A-1-310742 is ion-exchanged and supported on zeolite. A so-called NO X in which a supported catalyst layer coated with a noble metal is provided on a refractory support.
Catalysts have been proposed. [0004] [SUMMARY OF THE INVENTION Incidentally, NO X catalyst as described above, for example, A / F = 22 (λ = 1.5) about the re - in the exhaust gas corresponding to the emission of air-fuel ratio, FIG. As shown by the solid line I in FIG. 4, it has good purification characteristics even when cold with respect to HC. However, near the stoichiometric air-fuel ratio, as shown by the broken line II, the characteristics during cold are inferior. Also, the purification rate is low even in the warm state. Therefore, there is a problem that it is not possible to purify a large amount of HC (CO) discharged in a combustion state close to the stoichiometric air-fuel ratio immediately after the start of the engine, and it has been desired to improve the HC purification rate even in a warm state. On the other hand, the NO X catalyst, although have good NO X purification properties compared to the three-way catalyst, as shown in FIG. 5, the temperature indicating the maximum NO X purification rate air-fuel ratio Li - down , That is, it decreases as the oxygen concentration in the exhaust gas increases, and the maximum NO X purification rate also decreases as the oxygen concentration in the exhaust gas increases. [0006] In view of the above circumstances, the present invention is intended of the NO X purification while characteristics maintaining, in particular exhaust gas purification device for an engine with dramatically improved HC purification characteristics at cold with NO X catalyst The purpose is to provide. [0007] An exhaust gas purifying apparatus for an engine according to the present invention is provided in an exhaust passage of the engine, and is provided with an exhaust gas.
The higher the oxygen concentration inside and the higher the catalyst inlet exhaust temperature
The higher the HC purification rate, the higher the NOx purification rate
Temperature decreases as the oxygen concentration in the exhaust gas increases.
And a catalyst having the property,
A secondary air supply means for supplying secondary air upstream;
Heats exhaust gas upstream of the catalyst location in the air passage
For detecting the exhaust gas temperature at the inlet of the catalyst.
The air temperature sensor and the oxygen concentration in the exhaust gas supplied to the catalyst
And O 2 sensor for detecting a value for degrees, the exhaust temperature及
The secondary air supply means and the heater according to the oxygen concentration
Control means for controlling the engine, wherein the control means
When the exhaust gas temperature rises to the specified
The exhaust gas is heated by operating only the heater
After the temperature has risen to the predetermined temperature, the secondary air supply means
Control to increase the oxygen concentration in the exhaust
It is characterized by having been done. According to the present invention, according to the present invention, the above-mentioned contact of the exhaust passage is provided.
Heater for heating the exhaust gas upstream of the medium installation position
Supply secondary air upstream of the catalyst disposition position in the exhaust passage.
Secondary air supply means for supplying air is provided in the exhaust system of the engine, and the control means controls the exhaust temperature to be a predetermined value when the engine is started.
Until the temperature rises, operate only the above heater.
On the other hand, after the exhaust temperature has risen to the predetermined temperature,
A) control the supply means to increase the oxygen concentration in the exhaust
Therefore, when the engine is started, the temperature of the catalyst can be quickly raised by the heater, and the secondary
Since the oxygen concentration in the exhaust gas can be increased by the supply means, the HC purification characteristics of the catalyst at the time of starting the engine can be dramatically improved. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of an exhaust gas purifying apparatus for an engine according to the present invention. In Figure 1, on the upstream side of the NO X catalyst 2 that is disposed in an exhaust passage 1, an electric heat for heating the exhaust - motor 3 is disposed, the electric heat - upstream of the motor 3, An air passage 4 for supplying secondary air to the exhaust passage 1 is connected. An air pump 5 is connected to the air passage 4. Furthermore, NO X catalyst 2 and the electric heat - the exhaust passage 1 between the motor 3, in addition to the O 2 sensor (not shown) for air-fuel ratio control that is provided in an exhaust passage of the engine side,
An O 2 sensor 6 for detecting the concentration of oxygen in the exhaust gas supplied to the catalyst 2 and a temperature sensor 7 for detecting the exhaust gas temperature at the inlet of the catalyst 2 are provided. 8 is a control
The controller 8 controls the electric heater 3 and the air pump 5 based on the outputs of the O 2 sensor 6 and the temperature sensor 7 and the outputs of the engine speed sensor 9 and the engine water temperature sensor 10 as follows. It is controlled in the manner described. [0012] That is, first, the oxygen concentration in FIG. 5 described above parameters - the characteristic curve showing the NO X purification rate and data, as shown in FIG. 2, the maximum value of the NO X purification rate is required minimum purification factor ( For example, an air-fuel ratio corresponding to an oxygen concentration that can satisfy 68%) and a temperature indicating the maximum NO X purification rate at the air-fuel ratio (hereinafter, this temperature is referred to as T 0 ) are, for example, A /
F = 22 (λ = 1.5) and temperature 220 ° C. When the engine is cold, such as when starting the engine, the air-fuel ratio of the engine is controlled so that λ = 1 until the engine coolant temperature reaches a specified temperature (for example, 80 ° C.). In the stopped state, the exhaust gas is heated by operating only the electric heater 3 to increase the exhaust gas temperature as quickly as possible. Then, the exhaust gas temperature becomes the temperature T 0.
When the temperature reaches (220 ° C.), the air pump 5 is operated to introduce secondary air into the exhaust passage 1 on the upstream side of the catalyst 2, and the oxygen concentration of the exhaust gas supplied to the catalyst 2 corresponds to λ = 1.5. I did it. Accordingly, as shown in FIG. 2, the HC purification rate is λ indicated by a broken line until point A when the exhaust gas temperature reaches T 0.
= 1, the temperature rises slowly along the characteristic curve II, and when the exhaust gas temperature reaches T 0 , it rises almost vertically at once, and the point B on the characteristic curve I at λ = 1.5 shown by a solid line. Will be reached. Therefore, the HC purification characteristics of the catalyst at the time of starting the engine can be dramatically improved. Thereafter, the electric heater 3 and the air pump are controlled so that the exhaust gas temperature is maintained at T 0 and the oxygen concentration in the exhaust gas is maintained at an oxygen concentration corresponding to λ = 1.5. by controlling the 5, while satisfying the required minimum purification efficiency for NO X purification rate it can lead to better HC purification characteristics. In this case, the fuel injection amount is controlled so that the air-fuel ratio becomes λ = 1 at the time of cold and idling.
In a lean-burn engine that executes air-fuel ratio control so that, for example, λ = 1.5 during normal running, secondary air is introduced into the exhaust passage 1 only during idling, and the introduction of secondary air is stopped during normal running. do it. In this embodiment, although the temperature sensor 7 is provided in the exhaust passage 1, it is attached to the catalyst 2,
The temperature of the catalyst 2 may be detected. FIG. 3 shows a control rule executed by the controller 8.
Show the chin flowchart. First, at step S1, the exhaust gas is heated by operating only the electric heater 3 simultaneously with the start of the engine. Next, in step S2, it is determined whether or not the engine water temperature has reached a specified temperature, that is, whether or not the engine is in a cold state. Is determined in step S3, the fuel injection amount is controlled so that the air-fuel ratio becomes λ = 1. [0019] In the next step S4, checks whether the exhaust gas temperature has reached T 0, when it is determined to have reached the T 0, the electric heat in step S5 - while to OFF data 3, the air pump 5 to activate secondary air as catalyst 2
And the oxygen concentration of the exhaust gas supplied to the catalyst 2 is made to correspond to λ = 1.5. Then, in the next step S6, it is checked whether or not the engine is executing air-fuel ratio control such that λ = 1. If λ = 1, the process proceeds to step S7 to determine whether the exhaust gas temperature has reached T 0 . It is checked whether the temperature has not reached, and if not reached, the electric heater 3 is turned on in step S8 to increase the exhaust gas temperature, and step S4
The feedback control of returning to step is executed. On the other hand, except when the engine is idling or cold, λ
= 1.5 in a lean-burn air-fuel ratio control, the determination in steps S6 and S9 is "N
Since the result is "O", the process proceeds to step S10, and further proceeds to step S11 to stop the air pump 5 and stop the introduction of the secondary air. Then, in step S12, the exhaust gas temperature becomes T 0.
Examines whether reached, when it is determined to have reached the T 0, the electric heat in step S13 - is turned ON motor 3. Next, in step S14, it is checked whether or not the exhaust gas temperature has reached T 0. When it is determined that the exhaust temperature has reached T 0 ,
In step S15, the electric heater 3 is turned off, and in step S1
The feedback control of returning to step 2 is executed. In addition,
If the introduction of the secondary air is stopped, the change in the exhaust gas temperature is reduced, so that the execution of the feedback control in steps S12 to S15 can be omitted. The control le as described above - by executing a routine, it is possible to remarkably improve the HC purification characteristics of the catalyst in the time of engine start, even improved cleaning characteristics for HC and NO X during travel be able to.
【図面の簡単な説明】
【図１】本発明の実施例の構成を概略的に示す図
【図２】本発明の作用の説明に供するグラフ
【図３】同制御ル−チンを示すフロ−チャ−ト
【図４】ＮＯX触媒の温度に対するＨＣ浄化特性を空燃
比をパラメ−タとして示すグラフ
【図５】ＮＯX触媒の温度に対するＮＯX浄化特性を空燃
比をパラメ−タとして示すグラフ
【符号の説明】
１ 排気通路
２ ＮＯX触媒
３ 電気ヒ−タ（加熱手段）
４ エア通路
５ エアポンプ（酸素濃度補正手段）
６ Ｏ2センサ
７ 排気温度センサ
８ コントロ−ラ（制御手段）
９ エンジン回転数センサ
10 エンジン水温センサBRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing the configuration of an embodiment of the present invention. FIG. 2 is a graph for explaining the operation of the present invention. FIG. 3 is a flowchart showing the control routine. Cha - graph showing the data - the NO X purification characteristic with respect to temperature in the graph Figure 5 NO X catalyst indicated as data of the air-fuel ratio parameter - DOO [4] the air-fuel ratio, HC purifying characteristics with respect to the temperature of the NO X catalyst parameters [Reference numerals] 1 exhaust passage 2 NO X catalyst 3 electric heat - data (heating means) 4 air passage 5 pump (oxygen concentration correcting means) 6 O 2 sensor 7 exhaust gas temperature sensor 8 controller - La (control means) 9 engine Speed sensor 10 Engine water temperature sensor
フロントページの続き (56)参考文献 特開 平４−214919（ＪＰ，Ａ) 特開 平５−59940（ＪＰ，Ａ) 特開 昭61−112715（ＪＰ，Ａ) 特開 昭50−32315（ＪＰ，Ａ) 特開 昭51−87614（ＪＰ，Ａ) 実開 昭47−23513（ＪＰ，Ｕ) 実開 平４−129829（ＪＰ，Ｕ) (58)調査した分野(Int.Cl.7，ＤＢ名) F01N 3/22 F01N 3/20 Continuation of front page (56) References JP-A-4-214919 (JP, A) JP-A-5-59940 (JP, A) JP-A-61-112715 (JP, A) JP-A-50-32315 (JP, A) JP-A-51-87614 (JP, A) JP-A 47-23513 (JP, U) JP-A 4-129829 (JP, U) (58) Fields investigated (Int. Cl. 7 , DB Name) F01N 3/22 F01N 3/20
Claims (1)
の酸素濃度が高くなるほど且つ触媒入口排気温度が高く
なるほどＨＣ浄化率が高くなり、最大ＮＯｘ浄化率を示
す温度が排気中の酸素濃度の増大に応じて低下する特性
を有する触媒と、 上記排気通路の上記触媒配設位置の上流に２次エアを供
給する２次エア供給手段と、 上記排気通路の上記触媒配設位置の上流にある排気を加
熱するためのヒータと、 上記触媒の入口排気温度を検出する排気温度センサと、 上記触媒に供給される排気中の酸素濃度に関する値を検
知するＯ2センサと、 上記排気温度及び酸素濃度に応じて上記２次エア供給手
段及びヒータを制御する制御手段とを備え、 上記制御手段は、エンジンの始動時に、排気温度が所定
温度に上がるまでの間、上記ヒータのみを作動させて排
気を加熱する一方、排気温度が上記所定温度に上がった
後、上記２次エア供給手段を制御して排気中の酸素濃度
を上昇させるように構成されていることを特徴とするエ
ンジンの排気浄化装置。(1) The HC purification rate, which is disposed in an exhaust passage of an engine and increases as the oxygen concentration in the exhaust gas and the exhaust gas temperature at the catalyst inlet increases, increases the maximum NOx purification rate. A catalyst having a characteristic that the temperature indicating the temperature decreases as the oxygen concentration in the exhaust gas increases, secondary air supply means for supplying secondary air to the exhaust passage upstream of the catalyst arrangement position, and the exhaust passage A heater for heating the exhaust gas upstream of the catalyst disposing position, an exhaust gas temperature sensor for detecting an exhaust gas temperature at the inlet of the catalyst, and a sensor for detecting a value relating to an oxygen concentration in the exhaust gas supplied to the catalyst. and 2 sensor, and a control means for controlling the secondary air supply means and the heater in accordance with the exhaust temperature and oxygen concentration, the control means, at the start of the engine, until the exhaust temperature is raised to a predetermined temperature , Hand you heat the exhaust by operating only the heater, after the exhaust temperature rises above a predetermined temperature, is configured to increase the oxygen concentration in the exhaust and controls the secondary air supply means An exhaust gas purification device for an engine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05032193A JP3467795B2 (en) | 1993-03-11 | 1993-03-11 | Engine exhaust purification device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP05032193A JP3467795B2 (en) | 1993-03-11 | 1993-03-11 | Engine exhaust purification device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06264728A JPH06264728A (en) | 1994-09-20 |
| JP3467795B2 true JP3467795B2 (en) | 2003-11-17 |
Family
ID=12855645
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP05032193A Expired - Fee Related JP3467795B2 (en) | 1993-03-11 | 1993-03-11 | Engine exhaust purification device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3467795B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102017107678A1 (en) * | 2017-04-10 | 2018-10-11 | Volkswagen Aktiengesellschaft | Method for starting up an internal combustion engine and motor vehicle with an internal combustion engine |
-
1993
- 1993-03-11 JP JP05032193A patent/JP3467795B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH06264728A (en) | 1994-09-20 |
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