JPH09173778A - Catalytic device for purifying exhaust gas - Google Patents
Catalytic device for purifying exhaust gasInfo
- Publication number
- JPH09173778A JPH09173778A JP7339333A JP33933395A JPH09173778A JP H09173778 A JPH09173778 A JP H09173778A JP 7339333 A JP7339333 A JP 7339333A JP 33933395 A JP33933395 A JP 33933395A JP H09173778 A JPH09173778 A JP H09173778A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- exhaust gas
- hydrocarbons
- electrothermal
- 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.)
- Pending
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
- F01N2240/18—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an adsorber or absorber
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2570/00—Exhaust treating apparatus eliminating, absorbing or adsorbing specific elements or compounds
- F01N2570/12—Hydrocarbons
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】 この発明は、内燃機関の排
気ガス浄化用触媒装置に関する。TECHNICAL FIELD The present invention relates to a catalyst device for purifying exhaust gas of an internal combustion engine.
【０００２】[0002]
【従来の技術】 従来の電熱触媒を用いる排気ガス浄化
用触媒装置として、特開平５−１１５７９３号公報に示
されるように、電熱触媒の後方に三元触媒を配置する構
成とし、電熱触媒のハニカム体をハニカム状構造体の中
心部から外周部に行くに従って排気ガス流方向の幅が順
次小さくなるハニカム体で構成することで昇温特性を改
善させエンジン始動直後の排気ガス浄化特性を向上させ
る構成のものが公知である。2. Description of the Related Art As a conventional exhaust gas purifying catalyst device using an electrothermal catalyst, as shown in Japanese Patent Application Laid-Open No. 5-115793, a three-way catalyst is arranged behind the electrothermal catalyst to form a honeycomb of electrothermal catalysts. A structure in which the temperature rise characteristics are improved and the exhaust gas purification characteristics are improved immediately after the engine is started by configuring the body as a honeycomb body in which the width in the exhaust gas flow direction gradually decreases from the central portion to the outer peripheral portion of the honeycomb structure. Are known.
【０００３】また、炭化水素吸着触媒を用いる排気ガス
浄化装置としては、特開平５−５９９４２号公報に示さ
れるように、第一の三元触媒または酸化触媒を設け、そ
の上流にＨＣ吸着触媒を設け、さらにその上流に第二の
三元触媒を設けて始動時の炭化水素を効率よく除去する
ように構成したものが公知である。Further, as an exhaust gas purifying apparatus using a hydrocarbon adsorption catalyst, as shown in JP-A-5-59942, a first three-way catalyst or an oxidation catalyst is provided, and an HC adsorption catalyst is provided upstream thereof. It is known that a hydrocarbon is provided and a second three-way catalyst is provided further upstream thereof to efficiently remove hydrocarbons at the time of starting.
【０００４】炭化水素吸着触媒と電熱触媒を組合せる排
気ガス浄化用触媒装置としては、本発明者は電熱触媒の
後方に炭化水素触媒と三元触媒を配置した排気ガス浄化
装置も考案している。As an exhaust gas purifying catalyst device in which a hydrocarbon adsorption catalyst and an electrothermal catalyst are combined, the present inventor has also devised an exhaust gas purifying device in which a hydrocarbon catalyst and a three-way catalyst are arranged behind the electrothermal catalyst. .
【０００５】[0005]
【発明が解決しようとする課題】 しかし、このような
排気浄化装置ではエンジン始動時の充分に排気ガス温度
が暖まっていない条件下で充分なＨＣ浄化性能を得るこ
とができない。電熱触媒では、電熱触媒をエンジン始動
直後から加熱しても充分に加熱されるまでの時間内はエ
ンジンから排出されるＨＣは浄化されない。炭化水素吸
着触媒を用いる排気浄化装置では、エンジン始動直後の
炭化水素は充分に浄化できるが排気温度が上昇するに従
い、吸着していた炭化水素が脱離することにより排出さ
れる炭化水素が増加してしまう。炭化水素吸着触媒と三
元触媒を組み合わせた排気ガス浄化用触媒装置では、炭
化水素吸着触媒の温度制御を正確に行えず脱離してくる
炭化水素の抑制を充分に行えないという問題がある。However, such an exhaust purification device cannot obtain sufficient HC purification performance under conditions where the exhaust gas temperature is not sufficiently warmed at the time of engine start. In the case of the electrothermal catalyst, even if the electrothermal catalyst is heated immediately after the engine is started, HC discharged from the engine is not purified within a time period until it is sufficiently heated. An exhaust gas purification device that uses a hydrocarbon adsorption catalyst can sufficiently purify hydrocarbons immediately after the engine is started, but as the exhaust temperature rises, the adsorbed hydrocarbons are desorbed and the amount of hydrocarbons discharged increases. Will end up. The exhaust gas purifying catalyst device in which the hydrocarbon adsorbing catalyst and the three-way catalyst are combined has a problem that the temperature of the hydrocarbon adsorbing catalyst cannot be accurately controlled and the desorbed hydrocarbon cannot be sufficiently suppressed.
【０００６】[0006]
【課題を解決するための手段】 この発明は、このよう
な従来の排気ガス浄化用触媒装置に対して、触媒変換装
置を電気的に加熱する電熱触媒として少なくとも炭化水
素を吸着する炭化水素吸着触媒をコートした触媒また
は、電熱触媒として炭化水素を吸着する炭化水素吸着触
媒と三元触媒を一層以上コートした触媒とし、その後方
に三元触媒を備えており、エンジン始動直後の排気ガス
温度が低い炭化水素吸着触媒が炭化水素を吸着できる温
度域では電熱触媒を加熱せず、炭化水素吸着触媒から炭
化水素が脱離する温度近くまで排気ガス温度が上昇した
ら電熱触媒を加熱するように制御し、さらに炭化水素吸
着触媒としてゼオライト粉末を主成分とするスラリーを
ハニカム担体にコーティングしたことを特徴とする排気
ガス浄化用触媒装置とすることで、上記問題点を解決す
ることを目的としている。The present invention provides a hydrocarbon adsorption catalyst that adsorbs at least hydrocarbons as an electrothermal catalyst that electrically heats a catalyst conversion device, in contrast to such a conventional exhaust gas purification catalyst device. Coated catalyst or a hydrocarbon adsorption catalyst that adsorbs hydrocarbons as an electrothermal catalyst and a catalyst coated with one or more three-way catalysts, and a three-way catalyst behind it is provided, and the exhaust gas temperature immediately after engine start is low. In the temperature range where the hydrocarbon adsorption catalyst can adsorb hydrocarbons, the electrothermal catalyst is not heated, and the electrothermal catalyst is controlled to be heated when the exhaust gas temperature rises to a temperature close to the temperature at which hydrocarbons are desorbed from the hydrocarbon adsorption catalyst, Furthermore, a catalyst device for exhaust gas purification, characterized in that a honeycomb carrier is coated with a slurry containing zeolite powder as a hydrocarbon adsorption catalyst. By doing so, the purpose is to solve the above problems.
【０００７】すなわち、請求項１記載の発明では、内燃
機関から排出される炭化水素を含有する排気ガス中の炭
化水素を浄化する排気ガス浄化用触媒装置において、触
媒変換装置を電気的に加熱する電熱触媒として少なくと
も炭化水素を吸着する炭化水素吸着触媒をコートした触
媒とし、その後方に三元触媒とを備えたことを特徴とす
る。また、請求項２記載の装置では、内燃機関から排出
される炭化水素を含有する排気ガス中の炭化水素を浄化
する排気ガス浄化用触媒装置において、触媒変換装置を
電気的に加熱する電熱触媒として少なくとも炭化水素を
吸着する炭化水素吸着触媒と三元触媒とを一層以上コー
トした触媒とし、その後方に三元触媒とを備えたことを
特徴とする。なお、前記請求項１に記載の排気ガス浄化
用触媒装置において、エンジン始動直後の排気ガス温度
が低い領域では電熱触媒を加熱せず、排気ガス温度が上
昇した領域では電熱触媒を加熱するように制御してもよ
い（請求項３）。また、請求項４に記載のように、前記
炭化水素吸着触媒としてゼオライト粉末を主成分とする
スラリーを用いるようにしてもよい。That is, according to the first aspect of the invention, in the exhaust gas purifying catalyst device for purifying hydrocarbons contained in the exhaust gas containing hydrocarbons discharged from the internal combustion engine, the catalytic converter is electrically heated. The electrothermal catalyst is a catalyst coated with a hydrocarbon adsorption catalyst that adsorbs at least hydrocarbons, and a three-way catalyst is provided behind the catalyst. Further, in the apparatus according to claim 2, in the exhaust gas purifying catalyst device for purifying hydrocarbons contained in the exhaust gas containing hydrocarbons discharged from the internal combustion engine, an electrothermal catalyst for electrically heating the catalyst conversion device is used. The catalyst is characterized by further coating at least a hydrocarbon adsorption catalyst that adsorbs hydrocarbons and a three-way catalyst, and is provided with a three-way catalyst behind it. In the exhaust gas purifying catalyst device according to claim 1, the electrothermal catalyst is not heated in a region where the exhaust gas temperature is low immediately after the engine is started, and is heated in a region where the exhaust gas temperature is increased. It may be controlled (claim 3). Further, as described in claim 4, a slurry containing zeolite powder as a main component may be used as the hydrocarbon adsorption catalyst.
【０００８】[0008]
【発明の実施の形態】 以下、この発明について説明す
る。この発明の実施の形態を示す。図１に本発明の望ま
しい排気ガス浄化用触媒装置である実施の形態を示して
いる。図に示すように、エンジン１の排気系の直後に炭
化水素吸着触媒をコートした電熱触媒２が配置され、そ
の後方に三元触媒３を配置してある。BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below. An embodiment of the present invention will be described. FIG. 1 shows an embodiment of a desirable exhaust gas purifying catalyst device of the present invention. As shown in the figure, an electrothermal catalyst 2 coated with a hydrocarbon adsorption catalyst is arranged immediately after the exhaust system of the engine 1, and a three-way catalyst 3 is arranged behind it.
【０００９】この電熱触媒２の一実施例（実施例１）の
調製方法を次に示す。ＵＳＹ（ＳｉＯ２／Ａ１２０３＝
５０）ゼオライト１００部、シリカゾル（固形分２０
％）６５部、水６５部をボールミルポットに投入し、
６．５時間粉砕してスラリーを得た。得られたスラリー
を電熱触媒担体基材に塗布し乾燥後、４００℃で１時
間、空気雰囲気中で仮焼成した。このコーティング作業
を、塗布量が焼成後に約１５０ｇ／Ｌになるまで繰り返
した後６５０℃で４時間焼成を行い電熱加熱触媒を調製
する。A method for preparing one example (Example 1) of the electrothermal catalyst 2 will be described below. USY (SiO2 / A1203 =
50) 100 parts of zeolite, silica sol (solid content 20)
%) 65 parts and 65 parts of water are put into a ball mill pot,
It was pulverized for 6.5 hours to obtain a slurry. The obtained slurry was applied to an electrothermal catalyst carrier substrate, dried, and then calcined at 400 ° C. for 1 hour in an air atmosphere. This coating operation is repeated until the coating amount becomes about 150 g / L after firing, and then firing at 650 ° C. for 4 hours to prepare an electrothermal heating catalyst.
【００１０】図２に、本実施の形態における電熱触媒２
の加熱を行う際の制御フローを示してある（本フロー
は、エンジン始動時毎に実行される）。Ｓ１０１でエン
ジン１からのスタータ信号を読み込み、エンジン１の始
動の判定を行う。Ｓ１０２で、エンジン１の水温から冷
間始動の判定及び炭化水素吸着触媒が炭化水素を吸着す
る温度域か脱離する温度域かの判定を行い、脱離を開始
する温度域であれば、電熱触媒２へ電流を流して加熱を
行い、それ以外は加熱を行わない。FIG. 2 shows an electrothermal catalyst 2 according to this embodiment.
The control flow when performing the heating is shown (this flow is executed every time the engine is started). In S101, the starter signal from the engine 1 is read, and the start of the engine 1 is determined. In S102, a cold start determination is made based on the water temperature of the engine 1 and a temperature range in which the hydrocarbon adsorption catalyst adsorbs hydrocarbons or a desorption temperature range is determined. An electric current is applied to the catalyst 2 to heat it, and no heating is applied to other catalysts.
【００１１】次に作用を説明する。本実施の形態の排気
ガス浄化用触媒装置においては、触媒変換装置を電気的
に加熱する電熱触媒２として炭化水素を吸着する炭化水
素吸着触媒をコートした触媒とし、その後方に三元触媒
３を備えており、エンジン始動直後の排気ガス温度が低
い炭化水素吸着触媒が炭化水素を吸着できる温度域では
電熱触媒２を加熱せず、炭化水素吸着触媒から炭化水素
が脱離する温度近くまで排気ガス温度が上昇したら電熱
触媒２を加熱するように制御し、さらに炭化水素吸着触
媒としてゼオライト粉末を主成分とするスラリーをハニ
カム担体にコーティングしたことを特徴とする排気浄化
装置としている。Next, the operation will be described. In the exhaust gas purifying catalyst device of the present embodiment, the electrothermal catalyst 2 that electrically heats the catalytic converter is a catalyst coated with a hydrocarbon adsorption catalyst that adsorbs hydrocarbons, and the three-way catalyst 3 is provided behind it. Equipped with a low exhaust gas temperature immediately after the engine starts, the electrothermal catalyst 2 is not heated in a temperature range where the hydrocarbon adsorbing catalyst can adsorb hydrocarbons, and the exhaust gas reaches a temperature close to the temperature at which hydrocarbons desorb from the hydrocarbon adsorbing catalyst. The exhaust gas purification device is characterized in that the electrothermal catalyst 2 is controlled to be heated when the temperature rises, and a honeycomb carrier is coated with a slurry having a zeolite powder as a main component as a hydrocarbon adsorption catalyst.
【００１２】触媒変換装置を電気的に加熱する電熱触媒
２は、金属担体を用いたハニカムを担体とし表面に三元
触媒層をコーティングして触媒としており、定電圧で電
流値を制御して加熱することによりコート層中の温度を
上昇させ急速に触媒活性を立ち上げることが可能であ
る。この電熱触媒２に炭化水素の吸着触媒をコーティン
グした触媒はエンジン始動直後の排気温度の低い条件で
炭化水素を吸着し排出される炭化水素を大幅に減少させ
る働きがあるが、排気ガスの温度が上昇してくると吸着
していた炭化水素が脱離するという特性を合わせ持って
いる。この時、炭化水素の脱離は触媒層の昇温速度が速
いほど高温側にずれていくという特性がある。炭化水素
の脱離する温度が高温側にずれることで実走行中におい
ても炭化水素の排出量を抑制することができる。しかし
ながら、ただ単純にエンジン１から排出される排ガスを
炭化水素吸着触媒に通過させても昇温速度は排ガスの温
度で決まってしまい炭化水素吸着触媒の炭化水素の脱離
を抑制することは困難であるが、電熱触媒２を用いて排
ガス温度をコントロールすることで、炭化水素吸着触媒
からの炭化水素の脱離を抑制することが可能になり、排
出される炭化水素を大幅に低下させることができる。The electrothermal catalyst 2 for electrically heating the catalytic converter uses a honeycomb made of a metal carrier as a carrier and has a three-way catalyst layer coated on the surface thereof as a catalyst. The current value is controlled at a constant voltage to heat the catalyst. By doing so, it is possible to raise the temperature in the coat layer and rapidly raise the catalytic activity. The catalyst obtained by coating the electrothermal catalyst 2 with a hydrocarbon adsorption catalyst has a function of adsorbing hydrocarbons and significantly reducing the exhausted hydrocarbons under the condition of low exhaust gas temperature immediately after the engine is started. It also has the property that the adsorbed hydrocarbons are desorbed when it rises. At this time, the desorption of hydrocarbons has a characteristic that the higher the heating rate of the catalyst layer, the more it deviates to the higher temperature side. By shifting the temperature at which hydrocarbons are desorbed to the high temperature side, the amount of hydrocarbons discharged can be suppressed even during actual traveling. However, even if the exhaust gas discharged from the engine 1 is simply passed through the hydrocarbon adsorption catalyst, the temperature rising rate is determined by the temperature of the exhaust gas, and it is difficult to suppress the desorption of hydrocarbons of the hydrocarbon adsorption catalyst. However, by controlling the exhaust gas temperature using the electrothermal catalyst 2, it becomes possible to suppress the desorption of hydrocarbons from the hydrocarbon adsorption catalyst, and it is possible to significantly reduce the exhausted hydrocarbons. .
【００１３】電熱触媒２の他の実施例を示す。 （実施例２）実施例１のＵＳＹゼオライトの代わりにＵ
ＳＹゼオライトとＺＳＭ−５ゼオライトを用いた以外は
実施例１と同様とした。ＵＳＹ（ＳｉＯ２／Ａ１２０３
＝５０）ゼオライト５０部、ＺＳＭ−５（ＳｉＯ２／Ａ
１２０３＝７００）ゼオライト５０部、シリカゾル（固
形分２０％）６５部、水６５部をボールミルポットに投
入し、６．５時間粉砕してスラリーを得た。得られたス
ラリーを電熱触媒担体基材に塗布し乾燥後、４００℃で
１時間、空気雰囲気中で仮焼成した。この時の塗布量
は、焼成後に約６０ｇ／Ｌになるようにし、同様なコー
トを２回繰り返し合計したコート量が１５０ｇ／Ｌにな
るようにした後６５０℃で４時間焼成を行い電熱触媒２
を調製する。本実施例における電熱触媒２の加熱を行う
際の、制御フローは上述の実施の形態と同様のフローを
用いることができる。Another embodiment of the electrothermal catalyst 2 will be shown. (Example 2) Instead of the USY zeolite of Example 1, U
Same as Example 1 except that SY zeolite and ZSM-5 zeolite were used. USY (SiO2 / A1203
= 50) 50 parts of zeolite, ZSM-5 (SiO2 / A)
1203 = 700) 50 parts of zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a ball mill pot and pulverized for 6.5 hours to obtain a slurry. The obtained slurry was applied to an electrothermal catalyst carrier substrate, dried, and then calcined at 400 ° C. for 1 hour in an air atmosphere. The coating amount at this time was set to about 60 g / L after firing, and the same coating was repeated twice to give a total coating amount of 150 g / L, and then firing was performed at 650 ° C. for 4 hours to carry out electrothermal catalyst 2
Is prepared. The control flow when heating the electrothermal catalyst 2 in the present embodiment can use the same flow as in the above-described embodiment.
【００１４】（実施例３）電熱触媒担体基材に炭化水素
吸着触媒層をコーティングした後、三元触媒をコーティ
ングする以外は実施例１と同様とした。電熱加熱触媒担
体基材にＵＳＹ（ＳｉＯ２／Ａ１２０３＝５０）ゼオラ
イト１００部、シリカゾル（固形分２０％）６５部、水
６５部をボールミルポットに投入し、６．５時間粉砕し
て得たスラリーを塗布し乾燥後、４００℃で１時間、空
気雰囲気中で仮焼成した。この時の塗布量は、焼成後に
約６０ｇ／Ｌになるようにし、同様なコートを２回繰り
返し合計したコート量が１５０ｇ／Ｌになるようにした
後６５０℃で４時間焼成を行い電熱触媒を調製する。さ
らにこの上に、三元触媒層としてＰｔ，Ｒｈ，Ｐｄの貴
金属の内少なくとも一種以上を含む通常の三元触媒スラ
リーをコーティングし同様に乾燥、焼成を行い電熱触媒
２を調製する。本実施例における電熱触媒２の加熱を行
う際の、制御フローは上述の実施の形態と同様のフロー
を用いることができる。(Example 3) The same procedure as in Example 1 was carried out except that the hydrocarbon adsorption catalyst layer was coated on the electrothermal catalyst carrier substrate and then the three-way catalyst was coated. 100 parts of USY (SiO2 / A1203 = 50) zeolite, 65 parts of silica sol (solid content 20%), and 65 parts of water were put into a ball mill pot on an electrothermal heating catalyst carrier substrate, and the slurry obtained by pulverizing for 6.5 hours was obtained. After coating and drying, it was calcined at 400 ° C. for 1 hour in an air atmosphere. The coating amount at this time was set to about 60 g / L after firing, and the same coating was repeated twice to give a total coating amount of 150 g / L, followed by firing at 650 ° C. for 4 hours to prepare an electrothermal catalyst. Prepare. Further, an ordinary three-way catalyst slurry containing at least one of Pt, Rh, and Pd noble metals is coated on this as a three-way catalyst layer, and similarly dried and baked to prepare the electrothermal catalyst 2. The control flow when heating the electrothermal catalyst 2 in the present embodiment can use the same flow as in the above-described embodiment.
【００１５】（実施例４）電熱触媒担体基材に三元触媒
層をコーティング後に炭化水素吸着触媒層をコーティン
グする以外は実施例１と同様とした。(Example 4) The same procedure as in Example 1 was carried out except that the electrothermal catalyst carrier substrate was coated with the three-way catalyst layer and then with the hydrocarbon adsorption catalyst layer.
【００１６】電熱加熱担体基材に三元触媒層としてＰ
ｔ，Ｒｈ，Ｐｄの貴金属の内少なくとも一種以上を含む
通常の三元触媒スラリーをコーティングし実施例１と同
様に乾燥、焼成を行い調製する。さらにこの上に、ＵＳ
Ｙ（ＳｉＯ２／Ａ１２０３＝５０）ゼオライト１００
部、シリカゾル（固形分２０％）６５部、水６５部をボ
ールミルポットに投入し、６．５時間粉砕して得たスラ
リーを塗布し乾燥後、４００℃で１時間、空気雰囲気中
で仮焼成した。この時の塗布量は、焼成後に約６０ｇ／
Ｌになるようにし、同様なコートを２回繰り返し合計し
たコート量が１５０ｇ／Ｌになるようにした後６５０℃
で４時間焼成を行い電熱触媒２を調製する。本実施例に
おける電熱触媒２の加熱を行う際の、制御フローも上述
の実施の形態と同様のフローを用いることができる。P as a three-way catalyst layer on an electrothermal heating carrier substrate
A normal three-way catalyst slurry containing at least one of t, Rh, and Pd noble metals is coated and dried and calcined in the same manner as in Example 1 to prepare. On top of this, US
Y (SiO2 / A1203 = 50) zeolite 100
Parts, 65 parts of silica sol (solid content 20%), and 65 parts of water are put into a ball mill pot, and the slurry obtained by pulverizing for 6.5 hours is applied and dried, and then calcined at 400 ° C. for 1 hour in an air atmosphere. did. The coating amount at this time is about 60 g /
650 ° C. after adjusting the coating amount to L and repeating the same coating twice to adjust the total coating amount to 150 g / L.
And calcining for 4 hours to prepare electrothermal catalyst 2. The control flow when heating the electrothermal catalyst 2 in the present embodiment can also use the same flow as in the above-described embodiment.
【００１７】なお、各実施例に用いるゼオライトとして
は、ＵＳＹ、ＺＳＭ−５以外にモルデナイト、ベータゼ
オライトのＳｉ／２Ａ１比の高いゼオライトや、それぞ
れのゼオライトにＰｄ，Ｃｕ，Ｃｏ等の金属を担持した
ゼオライトを用いることができる。In addition to USY and ZSM-5, the zeolite used in each example is mordenite, a zeolite with a high Si / 2A1 ratio of beta zeolite, or a metal such as Pd, Cu or Co supported on each zeolite. Zeolites can be used.
【００１８】（比較例１）電熱加熱担体基材にＰｔ，Ｒ
ｈ，Ｐｄの内、少なくとも一種以上を含む通常の三元触
媒スラリーをコーティングし乾燥、４００℃で２時間、
空気雰囲気中で焼成を行い電熱触媒とした。電熱触媒へ
の制御としては、コールドスタート時のエンジンスター
ト直後より加熱を行なうように制御を行う排気ガス浄化
用触媒装置を比較例１とした。(Comparative Example 1) Pt, R was used as the base material for the electrothermal heating carrier.
A normal three-way catalyst slurry containing at least one of h and Pd is coated and dried at 400 ° C. for 2 hours,
Firing was performed in an air atmosphere to obtain an electrothermal catalyst. As the control for the electrothermal catalyst, Comparative Example 1 was an exhaust gas purifying catalyst device in which heating was controlled immediately after the engine was started at the cold start.
【００１９】各実施例、比較例の電熱触媒２を図１の実
施の形態に適用して下記評価条件でＨＣ浄化特性評価
（ＦＴＰ７５ Ａ−ｂａｇ）を日産自動車（株）製車両
（排気量 ３Ｌ）を用いて行った。その結果を図３に示
す。Applying the electrothermal catalyst 2 of each of the examples and the comparative example to the embodiment of FIG. 1, an HC purification characteristic evaluation (FTP75 A-bag) was carried out under the following evaluation conditions for a vehicle manufactured by Nissan Motor Co., Ltd. (displacement: 3 L). ) Was used. The result is shown in FIG.
【００２０】性能評価条件 評価条件としては、エンジン始動時に排出されるＨＣ浄
化能を評価するためＡ−ｂａｇ ０〜１２５秒間のエミ
ッション低減率を測定した。Performance Evaluation Conditions As the evaluation conditions, the emission reduction rate of A-bag for 0 to 125 seconds was measured in order to evaluate the HC purification ability discharged at the engine start.
【００２１】 ガス組成 エンジン始動時（０〜１２５秒） 芳香族 ４４．４％ パラフィン ３３．３％ オレフィン ２２．３％Gas composition At engine start (0 to 125 seconds) Aromatic 44.4% Paraffin 33.3% Olefin 22.3%
【００２２】[0022]
【発明の効果】 以上説明してきたように、本発明によ
れば、その構成を、触媒変換装置を電気的に加熱する電
熱触媒として、少なくとも炭化水素を吸着する炭化水素
吸着触媒をコートした触媒または、電熱触媒として、炭
化水素を吸着する炭化水素吸着触媒と三元触媒層を一層
以上コートした触媒とし、その後方に三元触媒層を備え
ており、エンジン始動直後の排気ガス温度が低い炭化水
素吸着触媒が炭化水素を吸着できる温度域では電熱触媒
を加熱せず、炭化水素吸着触媒から炭化水素が脱離する
温度近くまで排気ガス温度が上昇したら電熱触媒を加熱
するように制御し、さらに炭化水素吸着触媒としてゼオ
ライト粉末を主成分とするスラリーをハニカム担体にコ
ーティングしたことを特徴とする排気ガス浄化用触媒装
置とすることで、エンジン始動直後の炭化水素の排出量
を大幅に低減できる。As described above, according to the present invention, a catalyst coated with a hydrocarbon adsorption catalyst that adsorbs at least hydrocarbons is used as an electrothermal catalyst that electrically heats the catalytic converter, or As an electrothermal catalyst, a hydrocarbon adsorption catalyst that adsorbs hydrocarbons and a catalyst that has one or more three-way catalyst layers coated, and a three-way catalyst layer behind it are provided, and hydrocarbons with low exhaust gas temperature immediately after engine startup The electrothermal catalyst is not heated in the temperature range where the adsorption catalyst can adsorb hydrocarbons, but the electrothermal catalyst is controlled to be heated when the exhaust gas temperature rises to a temperature close to the temperature at which hydrocarbons are desorbed from the hydrocarbon adsorption catalyst. By providing a catalyst carrier for exhaust gas purification, which is characterized in that a honeycomb carrier is coated with a slurry containing zeolite powder as a hydrogen adsorption catalyst. Emissions of hydrocarbons immediately after engine startup can be significantly reduced.
【図１】本発明の実施の形態を示す構成図である。FIG. 1 is a configuration diagram showing an embodiment of the present invention.
【図２】実施の形態の電熱触媒の制御流れを示すフロー
チャートである。FIG. 2 is a flowchart showing a control flow of the electrothermal catalyst according to the embodiment.
【図３】実施例および比較例の評価結果を示す図であ
る。FIG. 3 is a diagram showing evaluation results of examples and comparative examples.
１ エンジン ２ 電熱触媒 ３ 三元触媒 1 engine 2 electrothermal catalyst 3 three-way catalyst
Claims (4)
する排気ガス中の炭化水素を浄化する排気ガス浄化用触
媒装置において、 触媒変換装置を電気的に加熱する電熱触媒として少なく
とも炭化水素を吸着する炭化水素吸着触媒をコートした
触媒とし、その後方に三元触媒とを備えたことを特徴と
する排気ガス浄化用触媒装置。1. A catalyst device for purifying hydrocarbons in exhaust gas containing hydrocarbons discharged from an internal combustion engine, wherein at least hydrocarbons are adsorbed as an electrothermal catalyst for electrically heating a catalyst conversion device. A catalyst device for purifying exhaust gas, comprising a catalyst coated with a hydrocarbon adsorption catalyst, and a three-way catalyst behind the catalyst.
する排気ガス中の炭化水素を浄化する排気ガス浄化用触
媒装置において、 触媒変換装置を電気的に加熱する電熱触媒として少なく
とも炭化水素を吸着する炭化水素吸着触媒と三元触媒と
を一層以上コートした触媒とし、その後方に三元触媒と
を備えたことを特徴とする排気ガス浄化用触媒装置。2. A catalytic converter for purifying hydrocarbons in exhaust gas containing hydrocarbons discharged from an internal combustion engine, wherein at least hydrocarbons are adsorbed as an electrothermal catalyst for electrically heating a catalytic converter. An exhaust gas purifying catalytic device comprising a hydrocarbon adsorption catalyst and a three-way catalyst coated at least one layer, and a three-way catalyst behind the catalyst.
媒装置において、エンジン始動直後の排気ガス温度が低
い領域では電熱触媒を加熱せず、排気ガス温度が上昇し
た領域では電熱触媒を加熱するように制御したことを特
徴とする排気ガス浄化用触媒装置。3. The exhaust gas purifying catalyst device according to claim 1, wherein the electrothermal catalyst is not heated in a region where the exhaust gas temperature is low immediately after engine startup, and is heated in a region where the exhaust gas temperature rises. The exhaust gas purifying catalyst device is characterized in that it is controlled as follows.
粉末を主成分とするスラリーを用いることを特徴とする
請求項１記載の排気ガス浄化用触媒装置。4. The exhaust gas purifying catalyst device according to claim 1, wherein a slurry containing zeolite powder as a main component is used as the hydrocarbon adsorption catalyst.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7339333A JPH09173778A (en) | 1995-12-26 | 1995-12-26 | Catalytic device for purifying exhaust gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7339333A JPH09173778A (en) | 1995-12-26 | 1995-12-26 | Catalytic device for purifying exhaust gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09173778A true JPH09173778A (en) | 1997-07-08 |
Family
ID=18326466
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7339333A Pending JPH09173778A (en) | 1995-12-26 | 1995-12-26 | Catalytic device for purifying exhaust gas |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09173778A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3620625A1 (en) | 2018-09-06 | 2020-03-11 | Toyota Jidosha Kabushiki Kaisha | Exhaust after treatment system |
-
1995
- 1995-12-26 JP JP7339333A patent/JPH09173778A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3620625A1 (en) | 2018-09-06 | 2020-03-11 | Toyota Jidosha Kabushiki Kaisha | Exhaust after treatment system |
| JP2020041430A (en) * | 2018-09-06 | 2020-03-19 | トヨタ自動車株式会社 | Post-exhaust treatment device |
| US10920634B2 (en) | 2018-09-06 | 2021-02-16 | Toyota Jidosha Kabushiki Kaisha | Exhaust after treatment system |
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