JP3046051B2 - Engine exhaust gas purifier - Google Patents
Engine exhaust gas purifierInfo
- Publication number
- JP3046051B2 JP3046051B2 JP2261100A JP26110090A JP3046051B2 JP 3046051 B2 JP3046051 B2 JP 3046051B2 JP 2261100 A JP2261100 A JP 2261100A JP 26110090 A JP26110090 A JP 26110090A JP 3046051 B2 JP3046051 B2 JP 3046051B2
- Authority
- JP
- Japan
- Prior art keywords
- nox
- exhaust gas
- adsorbing member
- temperature
- 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
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
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
- F01N3/0828—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents characterised by the absorbed or adsorbed substances
- F01N3/0842—Nitrogen oxides
-
- 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
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/0807—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents
- F01N3/0814—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by using absorbents or adsorbents combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
-
- 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
- F01N2250/00—Combinations of different methods of purification
- F01N2250/12—Combinations of different methods of purification absorption or adsorption, and catalytic conversion
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
- Exhaust Gas After Treatment (AREA)
- Treating Waste Gases (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明はエンジンの排気ガス浄化装置に関する。Description: TECHNICAL FIELD The present invention relates to an exhaust gas purifying apparatus for an engine.
（従来の技術） 近年、環境問題がクローズアップされてきており、酸
性雨の原因となるNOxが規制化される兆しが高まりつつ
ある。その場合、特に、ディーゼルエンジン搭載車は、
酸素過剰雰囲気下で運転されているため、NOxの還元除
去が難しく、このNOxの規制強化が大きな命題として与
えられている。(Prior Art) In recent years, environmental issues have been highlighted, and there are increasing signs that NOx causing acid rain is being regulated. In that case, especially the car with diesel engine,
Since it is operated in an oxygen-excess atmosphere, it is difficult to reduce and remove NOx, and this stricter regulation of NOx is given as a major proposition.
そして、このような状況下で、NOxを直接N2およびO2
などに分解する銅イオン交換ゼオライトが発表され、大
きな話題を呼んでいる。この銅イオン交換ゼオライト
は、ゼオライトに遷移金属をイオン交換担持してなりNO
x分解性能を有する還元触媒として利用され、この還元
触媒と、アルミナに触媒成分を担持した酸化触媒又は三
元触媒とを排気流入側において上流側および下流側に順
に配置して、エンジンの排気ガス浄化装置として用いら
れている（特開平01−139145号公報参照）。And under such circumstances, NOx is directly converted to N 2 and O 2
Copper ion-exchanged zeolites that decompose into such have been announced and have attracted much attention. This copper ion-exchanged zeolite is obtained by carrying a transition metal on a zeolite by ion-exchange.
x Used as a reduction catalyst having decomposition performance, this reduction catalyst and an oxidation catalyst or a three-way catalyst in which a catalyst component is supported on alumina are sequentially arranged on the exhaust inflow side on the upstream side and the downstream side, and the exhaust gas of the engine is It is used as a purification device (see JP-A-01-139145).
（発明が解決しようとする課題） ところが、上記の如きエンジンの排気ガス浄化装置で
は、銅イオン交換ゼオライト（還元触媒）によりNOを分
解する活性温度が、第４図のＡに示すように、350℃付
近と高いため、この温度に達するまでは還元触媒として
の浄化能力（NOx分解能力）が発揮されず、低温時（350
℃以下）にNOxが浄化（分解）されないまま排出され
て、排気ガス浄化装置出口のNOx濃度が高いものとな
る。その場合、銅イオン交換ゼオライトは、活性浄化能
力自体を活発化させることはできても、活性温度を低温
側に移行させることが技術的に困難なものとなる。(Problems to be Solved by the Invention) However, in the exhaust gas purifying apparatus for an engine as described above, the activation temperature at which NO is decomposed by the copper ion-exchanged zeolite (reduction catalyst) is set to 350, as shown in FIG. ° C, the purification capacity (NOx decomposition ability) as a reduction catalyst is not exhibited until this temperature is reached.
(Less than or equal to ° C.), the NOx is discharged without being purified (decomposed), and the NOx concentration at the outlet of the exhaust gas purification device becomes high. In that case, the copper ion-exchanged zeolite can activate the activity purifying ability itself, but it is technically difficult to shift the activation temperature to a lower temperature side.
そこで、第３図に示すように、公知の複合酸化物BaO
−CuOが特異的に350℃以下の低温側の温度域までNOxを
吸着することに着目し、このBaO−CuOなる吸着材を有す
るNOx吸着部材と、上述の銅イオン交換ゼオライトとを
併用する、つまりNOx吸着部材と、還元触媒とを上流側
および下流側に配置した排気ガス浄化装置を構成してNO
を効果的に浄化することが考えられる。尚、第３図はCu
−アルカリ土類金属系複合酸化物のNO除去態様を示す図
である。Therefore, as shown in FIG.
-Focusing on the fact that CuO specifically adsorbs NOx up to a low temperature side of 350 ° C or lower, the NOx adsorbing member having this BaO-CuO adsorbent and the above-mentioned copper ion-exchanged zeolite are used in combination. In other words, the exhaust gas purifying apparatus in which the NOx adsorbing member and the reduction catalyst are arranged on the upstream
Can be effectively purified. FIG. 3 shows Cu
FIG. 3 is a view showing an embodiment of removing NO from an alkaline earth metal-based composite oxide.
しかしながら、排気流入側における排気ガス浄化装置
内では、その上流側と下流側とで温度格差が生じている
ため、上流側のNOx吸着部材が低温域から350℃以上の温
度域（高温域）に達してNOxが離脱し始めても、下流側
の銅イオン交換ゼオライトが未だ350℃付近の温度域に
達しないで還元触媒としての浄化能力を発揮せず、低温
時における排気ガス浄化装置出口のNOx濃度を効果的に
低減させることができない。However, in the exhaust gas purification device on the exhaust inflow side, there is a temperature difference between the upstream side and the downstream side, so the upstream NOx adsorbing member moves from a low temperature range to a temperature range of 350 ° C or more (high temperature range). Even if NOx begins to desorb, the downstream copper ion-exchanged zeolite still does not reach the temperature range around 350 ° C and does not exhibit the purification ability as a reduction catalyst, and the NOx concentration at the exhaust gas purifier outlet at low temperatures Cannot be effectively reduced.
本発明はかかる諸点に鑑みてなされたもので、その目
的とするところは、上記排気ガス浄化装置内において低
温時における温度格差が小さくなるよう,NOx吸着部材お
よび還元触媒に改良を加えて配置し、排気ガス浄化装置
出口のNOx濃度を効果的に低減させようとするものであ
る。The present invention has been made in view of such points, and an object of the present invention is to improve and arrange a NOx adsorbing member and a reducing catalyst in the exhaust gas purifying apparatus so that a temperature difference at a low temperature is reduced. Another object of the present invention is to effectively reduce the NOx concentration at the exhaust gas purifier outlet.
（課題を解決するための手段及びその作用） 上記目的を達成するため、請求項１の発明の解決手段
は、エンジンの排気ガス浄化装置として、エンジンの排
気系に、所定温度以下でNOxを吸着する吸着材を有するN
Ox吸着部材と、上記所定温度付近でNOx分解性能を有す
る還元触媒とを、上記NOx吸着部材が吸着したNOxを離脱
し始める温度のときに上記還元触媒がNOxを分解可能な
温度となるように上流側からNOx吸着部材および還元触
媒の順に設ける構成としたものである。(Means for Solving the Problems and Their Functions) In order to achieve the above object, a solution for the invention according to claim 1 is as an exhaust gas purifying device for an engine, wherein NOx is adsorbed to an exhaust system of the engine at a predetermined temperature or lower. N with adsorbent
The Ox adsorbing member and the reducing catalyst having NOx decomposing performance around the predetermined temperature, such that the reducing catalyst has a temperature at which the NOx adsorbing member can decompose NOx at a temperature at which the NOx adsorbing member starts to desorb the adsorbed NOx. In this configuration, the NOx adsorption member and the reduction catalyst are provided in this order from the upstream side.
ここで、請求項２の発明では、上記請求項１における
還元触媒は、ゼオライトに遷移金属を担持してなるもの
とする。また、請求項３の発明では、上記請求項１にお
けるNOx吸着部材は、BaO−CuOからなるものとする。さ
らに、請求項４の発明では、上記請求項１において、NO
x吸着部材と還元触媒とは上流側からNOx吸着部材及び還
元触媒の順に交互に複数組設けられているものとする。Here, in the invention according to claim 2, the reduction catalyst according to claim 1 has a zeolite supporting a transition metal. In the invention of claim 3, the NOx adsorbing member of claim 1 is made of BaO-CuO. Further, in the invention of claim 4, in the above-mentioned claim 1, NO
It is assumed that a plurality of sets of the x adsorption member and the reduction catalyst are provided alternately in the order of the NOx adsorption member and the reduction catalyst from the upstream side.
この場合、上記吸着材（NOx吸着部材）としては、BaO
−CuOに代表される複合酸化物を用いるのが適切であ
る。In this case, the adsorbent (NOx adsorbing member) is BaO
It is appropriate to use a composite oxide represented by -CuO.
また、上記還元触媒としては、銅イオンに代表される
遷移金属をイオン交換したゼオライト（銅イオン交換ゼ
オライト）を用いるのが適切である。このイオン交換す
る遷移金属は、Cuをはじめ、Co,Ni,Cr,Fe,Mn,Pt,Pd,Rh,
Ru,Ir等も単一または複合の形で使用可能である。As the reduction catalyst, zeolite obtained by ion-exchange of a transition metal represented by copper ions (copper ion-exchanged zeolite) is suitably used. The transition metals for this ion exchange include Cu, Co, Ni, Cr, Fe, Mn, Pt, Pd, Rh,
Ru, Ir, etc. can also be used in a single or composite form.
したがって、エンジンの吸気系に設けられたNOx吸着
部材および還元触媒は、該NOx吸着部材および還元触媒
が層状体に分割されてNOx吸着部材および還元触媒の厚
みが薄いものとなり、上流側から順に配したNOx吸着部
材および還元触媒に対しては、NOx吸着受材が吸着したN
Oxを離脱し始める温度の時に還元触媒がNOxを分解可能
な温度となるようにNOx吸着部材を介した還元触媒への
排気ガス温度の伝達が順次迅速になされる。Therefore, the NOx adsorbing member and the reducing catalyst provided in the intake system of the engine are divided into a layered body, the thickness of the NOx adsorbing member and the reducing catalyst is reduced, and the NOx adsorbing member and the reducing catalyst are arranged in order from the upstream side. The NOx adsorbing material adsorbs N
The temperature of the exhaust gas is sequentially and quickly transmitted to the reduction catalyst via the NOx adsorbing member so that the temperature of the reduction catalyst becomes a temperature at which NOx can be decomposed at the temperature at which Ox is released.
また、第２図に示すように、最上流側に位置するNOx
吸着部材の温度が350℃になると、このNOx吸着部材に吸
着されていたNOxの離脱が始まり、そのNOx吸着部材後の
NOx濃度が図中αで示すような特性となるが、層状体に
分割されたNOx吸着部材下流側の還元触媒の温度が直ち
に350℃になり、NOxをN2およびO2などに分解する。しか
も、最上流側に位置するNOx吸着部材下流側の還元触媒
によりN2およびO2などに分解し切れなかったNOxは、そ
の下流側におけるNOx吸着部材によって350℃まで吸着さ
れ、同様に350℃になるとその下流側の還元触媒でN2お
よびO2などに分解されることを繰り返す。これにより、
排気ガス浄化装置出口側のNOx濃度が図中βで示すよう
な特性となり、NOx吸着部材と還元触媒とが350℃に到達
するまでの温度差によりN2およびO2などに分解し切れな
かったNOxの濃度は可及的に小さな値となる。In addition, as shown in FIG.
When the temperature of the adsorption member reaches 350 ° C., desorption of the NOx adsorbed by the NOx adsorption member starts, and
Although the NOx concentration has the characteristic indicated by α in the figure, the temperature of the reduction catalyst downstream of the NOx adsorbing member divided into the layered body immediately becomes 350 ° C., and the NOx is decomposed into N 2 and O 2 . In addition, NOx that has not been completely decomposed into N 2 and O 2 by the reduction catalyst on the downstream side of the NOx adsorbing member located on the most upstream side is adsorbed to 350 ° C. by the NOx adsorbing member on the downstream side, and similarly 350 ° C. When it becomes, it is repeatedly decomposed into N 2 and O 2 by the reduction catalyst on the downstream side. This allows
The NOx concentration at the exhaust gas purifier outlet side has the characteristic indicated by β in the figure, and the NOx adsorbing member and the reduction catalyst could not be completely decomposed into N 2 and O 2 due to the temperature difference until reaching 350 ° C. The NOx concentration is as small as possible.
（実施例） 以下、本発明の実施例を図面に基づいて説明する。(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.
第１図は本発明の実施例に係るディーゼルエンジンの
排気ガス浄化装置Ｓを示し、この排気ガス浄化装置Ｓ
は、図示しないエンジンの排気流出側となる排気管１の
途中に設けられている。該排気ガス浄化装置Ｓは、排気
管１に一体的に形成されたケーシング２と、該ケーシン
グ２内に設けられ、350℃以下の低温域で排気ガス中に
含有されているNOxを吸着するNOx吸着部材３と、上記ケ
ーシング２内に設けられ、350℃付近からの高温域で排
気ガス中に含有されているNOxをN2およびO2などに分解
するNOx分解性能を有する還元触媒４とを備えてなる。FIG. 1 shows an exhaust gas purifying apparatus S for a diesel engine according to an embodiment of the present invention.
Is provided in the middle of the exhaust pipe 1 on the exhaust outlet side of the engine (not shown). The exhaust gas purifying apparatus S includes a casing 2 integrally formed with an exhaust pipe 1 and a NOx provided in the casing 2 and adsorbing NOx contained in exhaust gas at a low temperature range of 350 ° C. or less. An adsorbing member 3 and a reduction catalyst 4 provided in the casing 2 and having NOx decomposing performance for decomposing NOx contained in exhaust gas into N 2 and O 2 in a high temperature region around 350 ° C. Be prepared.
上記NOx吸着部材３の製造方法としては、例えば13.6g
秤量したCuO粉末と、例えば34.6g秤量したBaCO3粉末と
をボールミルに混合した後、1000℃（600℃〜1000℃）
で焼成して結晶化（酸化物の形にする）する。その後、
粉砕し、バインダー（アルミナスラリー）を10g加えて8
50℃で５時間焼成してNOx吸着材3aを有するNOx吸着部材
３が作られる。この場合、完成品の複合酸化物CuO:BaO
の比率は1:1となるように調整する。As a method of manufacturing the NOx adsorbing member 3, for example, 13.6 g
After mixing the weighed CuO powder and, for example, 34.6 g of weighed BaCO 3 powder in a ball mill, 1000 ° C. (600 ° C. to 1000 ° C.)
For crystallization (to form an oxide). afterwards,
Grind and add 10g of binder (alumina slurry) to 8
By firing at 50 ° C. for 5 hours, the NOx adsorbing member 3 having the NOx adsorbing material 3a is produced. In this case, the finished composite oxide CuO: BaO
Is adjusted to be 1: 1.
一方、還元触媒４の製造方法としては、Si/Al比が40
となるように混合されたシリカゾルとアルミナゾルとの
混合物60部に、ゼオライト（Si/Al比は40）粉末100部及
び水60部を加えて充分撹拌し、硝酸アルミニウム溶液で
pHを３〜６とし、ウォッシュコート用スラリーをバイン
ダーとして調整しておく。そして、コージェライト製モ
ノリス状ハニカム担体を水に浸漬し、余分な水を吹き払
った後、上記ウォッシュコート用スラリー（バインダ
ー）に浸漬し、取出した後余分なスラリーを圧縮空気で
吹き払い、80℃で20分乾燥させ、さらにこれを600℃で
１時間電気炉中で焼成する。これにより得られた焼成体
を0.02mol/程度の低濃度酢酸銅水溶液中に24時間浸漬
し、イオン交換操作を数回繰返して行った後、150℃で
２時間乾燥してイオン交換率143％の銅イオン交換ゼオ
ライト（還元触媒４）が作られる。この場合、第４図に
示すように、イオン交換率143％の銅イオン交換ゼオラ
イトにより分解された図中Ａで示すNOは、温度変化に応
じて、図中Ｂで示すN2、図中Ｃで示すO2および図中Ｄで
示すN2Oにそれぞれ分解される。また、イオン交換操作
を数回繰返して行うことにより浄化率が高められる。
尚、第４図は143％交換Cu−Ｚ触媒上でのNOの触媒分解
を示す図である。On the other hand, the production method of the reduction catalyst 4 is as follows.
60 parts of zeolite (Si / Al ratio: 40) powder and 60 parts of water are added to 60 parts of a mixture of silica sol and alumina sol mixed so that the mixture is sufficiently stirred, and then mixed with an aluminum nitrate solution.
The pH is adjusted to 3 to 6, and the slurry for wash coating is adjusted as a binder. Then, the cordierite monolithic honeycomb carrier is immersed in water, excess water is blown off, and then immersed in the wash coat slurry (binder). After drying at 20 ° C for 20 minutes, it is fired in an electric furnace at 600 ° C for 1 hour. The fired body thus obtained was immersed in an aqueous solution of copper acetate having a low concentration of about 0.02 mol / for 24 hours, ion-exchange operation was repeated several times, and then dried at 150 ° C. for 2 hours to obtain an ion exchange rate of 143%. Is produced (reduction catalyst 4). In this case, as shown in FIG. 4, NO shown in A in the figure decomposed by the copper ion-exchanged zeolite having an ion exchange rate of 143% is changed to N 2 shown in B in FIG. are disassembled into N 2 O indicated by O 2 and D in the figure indicated by. Further, the purification rate is increased by repeating the ion exchange operation several times.
FIG. 4 is a diagram showing catalytic decomposition of NO on a 143% exchanged Cu-Z catalyst.
そして、上記NOx吸着部材３および還元触媒４は、該
両者3,4が１対で１組となるよう，それぞれ層状体に分
割形成されている。また、上記NOx吸着部材３および還
元触媒４は、上流側からNOx吸着部材３および還元触媒
４の順に交互に密接状態で３組設けられている。The NOx adsorbing member 3 and the reduction catalyst 4 are separately formed in a layered body such that the two 3, 4 constitute one pair. The NOx adsorbing member 3 and the reducing catalyst 4 are provided in three sets alternately in close contact with the NOx adsorbing member 3 and the reducing catalyst 4 in this order from the upstream side.
上記NOx吸着部材３（NOx吸着材3a）と還元触媒４との
比率は、１対１とし、 50ccのNOx吸着部材３と、50ccの還元触媒４とで総計1
00ccを2cm〜4cmの層状にして配置する。The ratio between the NOx adsorbing member 3 (NOx adsorbing material 3a) and the reducing catalyst 4 is set to 1: 1. A total of 50cc NOx adsorbing member 3 and 50cc reducing catalyst 4 is 1
00cc is arranged in a layer of 2 cm to 4 cm.
また、テスト条件は、 SV（テストガスの空間速度）＝500〜1000（h-1） NO＝500ppm で行う。The test conditions are as follows: SV (space velocity of test gas) = 500 to 1000 (h -1 ) NO = 500 ppm.
したがって、排気管１の途中に設けられた排気ガス浄
化装置Ｓ内の複数組のNOx吸着部材３および還元触媒４
は、該NOx吸着部材３および還元触媒４が層状体に分割
されて１組当りのNOx吸着部材３および還元触媒３の厚
みが2cm〜4cm程度の薄いものとなり、上流側から交互に
配した３組のNOx吸着部材３および還元触媒４には、NOx
吸着部材３が吸着したNOxを離脱し始める温度の時に還
元触媒４がNOxを分解可能な温度となるようにNOx吸着部
材３を介した還元触媒４への排気ガス温度の伝達が順次
迅速になされる。この結果、排気ガス浄化装置Ｓ内にお
けるNOx吸着部材３と還元触媒４の温度格差を可及的に
小さくすることができる。Therefore, a plurality of sets of the NOx adsorbing member 3 and the reducing catalyst 4 in the exhaust gas purifying device S provided in the exhaust pipe 1 are provided.
Is that the NOx adsorbing member 3 and the reducing catalyst 4 are divided into a layered body, and the thickness of the NOx adsorbing member 3 and the reducing catalyst 3 per pair is as thin as about 2 cm to 4 cm, and the NOx adsorbing member 3 and the reducing catalyst 3 are alternately arranged from the upstream side. NOx adsorbing member 3 and reducing catalyst 4
The temperature of the exhaust gas is sequentially and quickly transmitted to the reduction catalyst 4 via the NOx adsorption member 3 so that the reduction catalyst 4 becomes a temperature at which the reduction catalyst 4 can decompose NOx at the temperature at which the adsorption member 3 starts to release the adsorbed NOx. You. As a result, the temperature difference between the NOx adsorption member 3 and the reduction catalyst 4 in the exhaust gas purification device S can be reduced as much as possible.
また、第２図で説明したように、最上流側に位置す
る、つまり上流側１組目のNOx吸着部材３の温度が350℃
になると、このNOx吸着部材３に吸着されていたNOxの離
脱が始まり、その１組目のNOx吸着部材３後のNOx濃度が
図中αで示すような特性となるが、層状体に分割された
NOx吸着部材３下流側における１組目の還元触媒４の温
度が直ちに350℃になり、NOxをN2,O2およびN2Oに分解す
る。しかも、１組目の還元触媒４によりN2、O2およびN2
Oに分解し切れなかったNOxは、その下流側における２組
目のNOx吸着部材３によって350℃まで吸着され、同様に
350℃になるとその下流側の２組目の還元触媒４でN2,O2
およびN2Oに分解されることを３組目まで繰り返す。こ
れにより、排気ガス浄化装置Ｓ出口側のNOx濃度が図中
βで示すような特性となり、NOx吸着部材３と還元触媒
４が350℃に到達するまでの温度差によりN2,O2およびN2
Oに分解し切れなかったNOxの濃度が可及的に小さな値と
なり、よって排気ガス浄化装置Ｓの浄化性能を向上させ
ることができる。Further, as described in FIG. 2, the temperature of the NOx adsorbing member 3 located at the most upstream side, that is, the first set of the upstream side NOx adsorbing members 3 is 350 ° C.
Then, the desorption of NOx adsorbed by the NOx adsorbing member 3 starts, and the NOx concentration after the first set of NOx adsorbing members 3 has a characteristic indicated by α in the figure, but is divided into layered bodies. Was
The temperature of the first set of reduction catalysts 4 on the downstream side of the NOx adsorbing member 3 immediately becomes 350 ° C. and decomposes NOx into N 2 , O 2 and N 2 O. In addition, N 2 , O 2 and N 2
NOx not completely decomposed into O is adsorbed to 350 ° C. by the second set of NOx adsorbing members 3 on the downstream side, and similarly,
When the temperature reaches 350 ° C., N 2 , O 2
And the decomposition into N 2 O up to the third set. As a result, the NOx concentration on the outlet side of the exhaust gas purifying device S has a characteristic indicated by β in the figure, and N 2 , O 2 and N 2 are determined by the temperature difference until the NOx adsorbing member 3 and the reduction catalyst 4 reach 350 ° C. Two
The concentration of NOx that has not been completely decomposed into O becomes a value as small as possible, so that the purification performance of the exhaust gas purification device S can be improved.
尚、本発明は上記実施例に限定されるものではなく、
その他種々の変形例を包含するものである。例えば、上
記実施例では、排気ガス浄化装置Ｓのケーシング２内に
NOx吸着部材３および還元触媒４を設けたが、エンジン
の排気系にNOx吸着部材および還元触媒を設けることに
よって排気ガス浄化装置が構成されるようにしても良
い。The present invention is not limited to the above embodiment,
Other various modifications are included. For example, in the above embodiment, the casing 2 of the exhaust gas purifying device S
Although the NOx adsorbing member 3 and the reducing catalyst 4 are provided, the exhaust gas purifying device may be configured by providing the NOx adsorbing member and the reducing catalyst in the exhaust system of the engine.
また、上記実施例では、ディーゼルエンジンの排気管
１に排気ガス浄化装置Ｓを設けたが、ガソリンエンジン
の排気系に排気ガス浄化装置を適用しても良いのは勿論
である。In the above embodiment, the exhaust gas purifier S is provided in the exhaust pipe 1 of the diesel engine. However, the exhaust gas purifier may be applied to the exhaust system of the gasoline engine.
（発明の効果） 以上の如く、本発明におけるエンジンの排気ガス浄化
装置によれば、NOx吸着部材および還元触媒を層状体に
分割してNOx吸着部材および還元触媒の厚みを薄いもの
とし、かつNOx吸着部材が吸着したNOxを離脱し始める温
度の時に還元触媒がNOxを分解可能な温度となるように
上流側から順に配して、NOx吸着部材を介した還元触媒
への排気ガス温度の伝達が順次迅速になされ、排気ガス
浄化装置内におけるNOx吸着部材と還元触媒の温度格差
を可及的に小さくすることができる。しかも、最上流側
に位置するNOx吸着部材下流側の還元触媒によりN2およ
びO2などに分解し切れなかったNOxが、その下流側にお
けるNOx吸着部材による吸着と、還元触媒でN2およびO2
などに分解されることを繰り返すことによって、NOx吸
着部材と還元触媒との温度差によるNOxの濃度が可及的
に小さな値となり、よって排気ガス浄化装置の浄化性能
を向上させることができる。(Effect of the Invention) As described above, according to the exhaust gas purifying apparatus for an engine of the present invention, the NOx adsorbing member and the reducing catalyst are divided into a layered body to reduce the thickness of the NOx adsorbing member and the reducing catalyst. When the temperature at which the adsorbing member starts to release the adsorbed NOx is arranged in order from the upstream side so that the reducing catalyst becomes a temperature at which the NOx can be decomposed, the transmission of the exhaust gas temperature to the reducing catalyst via the NOx adsorbing member is performed. The temperature difference between the NOx adsorbing member and the reduction catalyst in the exhaust gas purification device can be reduced as quickly as possible. Moreover, NOx that did fully decomposed such as N 2 and O 2 by the NOx adsorption member downstream of the reduction catalyst located at the most upstream side, and the adsorption by the NOx adsorption member at the downstream side, with a reducing catalytic N 2 and O Two
By repeating the decomposition, the concentration of NOx due to the temperature difference between the NOx adsorbing member and the reduction catalyst becomes as small as possible, so that the purification performance of the exhaust gas purification device can be improved.
【図面の簡単な説明】 第１図は本発明の実施例を示す，排気管途中の排気ガス
浄化装置の縦断側面図である。また、第２図ないし第４
図は変形例を示し、第２図はNOx吸着材および還元触媒
の所定温度到達時のNOx濃度特性を示す説明図、第３図
はBaO−CuOの温度に対する吸着特性図、第４図はNOの温
度に対する分解特性図である。 ３……NOx吸着部材 3a……NOx吸着材 ４……還元触媒 Ｓ……排気ガス浄化装置BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional side view of an exhaust gas purifying device in an exhaust pipe, showing an embodiment of the present invention. 2 to 4
FIG. 2 shows a modified example, FIG. 2 is an explanatory diagram showing NOx concentration characteristics of the NOx adsorbent and the reduction catalyst when a predetermined temperature is reached, FIG. 3 is an adsorption characteristic diagram with respect to temperature of BaO—CuO, and FIG. FIG. 4 is a decomposition characteristic diagram with respect to temperature of FIG. 3 NOx adsorbing member 3a NOx adsorbent 4 reduction catalyst S exhaust gas purification device
フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ Ｆ０１Ｎ 3/24 Ｂ０１Ｄ 53/34 １２９Ａ 3/28 ３０１ (58)調査した分野(Int.Cl.7，ＤＢ名) B01D 53/94 B01D 53/86 B01J 21/00 - 38/74 F01N 3/28 F01N 3/24 Continuation of the front page (51) Int.Cl. 7 identification code FI F01N 3/24 B01D 53/34 129A 3/28 301 (58) Field surveyed (Int.Cl. 7 , DB name) B01D 53/94 B01D 53 / 86 B01J 21/00-38/74 F01N 3/28 F01N 3/24
Claims (4)
を吸着する吸着材を有するNOx吸着部材と、上記所定温
度付近でNOx分解性能を有する還元触媒とが、上記NOx吸
着部材が吸着したNOxを離脱し始める温度のときに上記
還元触媒がNOxを分解可能な温度となるように上流側か
らNOx吸着部材および還元触媒の順に設けられているこ
とを特徴とするエンジンの排気ガス浄化装置。An exhaust system for an engine is provided with NOx at a predetermined temperature or lower.
The NOx adsorbing member having an adsorbent for adsorbing NOx and the reducing catalyst having NOx decomposing performance near the predetermined temperature are decomposed by the reducing catalyst at the temperature at which the NOx adsorbing member starts to desorb the adsorbed NOx. An exhaust gas purifying apparatus for an engine, wherein a NOx adsorbing member and a reducing catalyst are provided in this order from the upstream side so as to reach a possible temperature.
してなるものである請求項１記載のエンジンの排気ガス
浄化装置。2. The exhaust gas purifying apparatus for an engine according to claim 1, wherein the reduction catalyst is formed by supporting a transition metal on zeolite.
ある請求項１記載のエンジンの排気ガス浄化装置。3. The exhaust gas purifying apparatus for an engine according to claim 1, wherein the NOx adsorbing member is made of BaO—CuO.
吸着部材及び還元触媒の順に交互に複数組設けられてい
る請求項１記載のエンジンの排気ガス浄化装置。4. The NOx adsorbing member and the reduction catalyst are connected to the NOx adsorber from the upstream side.
2. The exhaust gas purifying apparatus for an engine according to claim 1, wherein a plurality of sets are provided alternately in the order of the adsorbing member and the reducing catalyst.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2261100A JP3046051B2 (en) | 1990-09-28 | 1990-09-28 | Engine exhaust gas purifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2261100A JP3046051B2 (en) | 1990-09-28 | 1990-09-28 | Engine exhaust gas purifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04141219A JPH04141219A (en) | 1992-05-14 |
| JP3046051B2 true JP3046051B2 (en) | 2000-05-29 |
Family
ID=17357083
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2261100A Expired - Fee Related JP3046051B2 (en) | 1990-09-28 | 1990-09-28 | Engine exhaust gas purifier |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3046051B2 (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0560991B9 (en) * | 1991-10-03 | 2005-01-26 | Toyota Jidosha Kabushiki Kaisha | Device for purifying exhaust of internal combustion engine |
| DE69326217T3 (en) * | 1992-06-12 | 2009-11-12 | Toyota Jidosha Kabushiki Kaisha, Toyota-shi | EXHAUST EMISSION CONTROL SYSTEM FOR INTERNAL COMBUSTION ENGINES |
| US5450722A (en) * | 1992-06-12 | 1995-09-19 | Toyota Jidosha Kabushiki Kaisha | Exhaust purification device of internal combustion engine |
| JP2692530B2 (en) * | 1992-09-02 | 1997-12-17 | トヨタ自動車株式会社 | Internal combustion engine |
| US5483795A (en) * | 1993-01-19 | 1996-01-16 | Toyota Jidosha Kabushiki Kaisha | Exhaust purification device of internal combustion engine |
| JP3246086B2 (en) * | 1993-06-11 | 2002-01-15 | トヨタ自動車株式会社 | Exhaust gas purification device for internal combustion engine |
| KR100290272B1 (en) * | 1996-06-10 | 2001-05-15 | 가나이 쓰토무 | Exhaust gas purifying apparatus for internal combustion engine and exhaust gas purifying catalyst for internal combustion engine |
| JP3965711B2 (en) | 1996-10-25 | 2007-08-29 | 株式会社日立製作所 | Nitrogen oxide purification catalyst and purification method |
| DE19712087C2 (en) * | 1997-03-22 | 1999-07-22 | Porsche Ag | Adsorber-catalyst combination for internal combustion engines |
| WO2000027508A1 (en) * | 1998-11-05 | 2000-05-18 | Toyota Jidosha Kabushiki Kaisha | Method and system for purifying exhaust gases and exhaust gas purification catalyst for use therein and method for preparation thereof |
| GB0013609D0 (en) * | 2000-06-06 | 2000-07-26 | Johnson Matthey Plc | Emission control |
| JP5987855B2 (en) * | 2014-03-14 | 2016-09-07 | トヨタ自動車株式会社 | Exhaust gas purification catalyst |
-
1990
- 1990-09-28 JP JP2261100A patent/JP3046051B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04141219A (en) | 1992-05-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2308596B1 (en) | Cu/zeolite SCR catalyst for NOx reduction in exhaust gases and manufacture method thereof | |
| JP3086015B2 (en) | Exhaust gas purification catalyst | |
| US20090317307A1 (en) | Exhaust gas purifying device | |
| CN109759035B (en) | NOxAdsorbent and preparation method and application thereof | |
| JP3046051B2 (en) | Engine exhaust gas purifier | |
| JP2773428B2 (en) | Exhaust gas purification method | |
| EP1166854B1 (en) | Exhaust gas purifing catalyst and method for purifying exhaust gas | |
| JP2800499B2 (en) | Hydrocarbon adsorbent | |
| JPH08229404A (en) | Exhaust gas purifying catalyst and apparatus | |
| JPH11276907A (en) | Catalyst for purifying exhaust gas and its production | |
| JP3219480B2 (en) | Exhaust gas treatment method and catalyst | |
| JP3014733B2 (en) | Engine exhaust gas purification apparatus and method of manufacturing the same | |
| JPH07100386A (en) | Catalyst for purification of exhaust gas | |
| JP3157555B2 (en) | Exhaust gas purification catalyst | |
| JPH0640964B2 (en) | Exhaust gas purification catalyst manufacturing method | |
| JPH04293519A (en) | Exhaust gas purification device | |
| JPH0435744A (en) | Catalytic body for purification of exhaust gas | |
| JP3321831B2 (en) | Exhaust gas purification catalyst | |
| JPH0663392A (en) | Adsorbent for hydrocarbon | |
| JP3311370B2 (en) | Exhaust purification catalyst system | |
| JPH04193347A (en) | Catalyst for purification of exhaust gas | |
| JPH07328448A (en) | Exhaust gas purification catalyst and device for purifying exhaust gas | |
| JPH04367713A (en) | Nitrogen oxide removal | |
| JP3291316B2 (en) | Exhaust gas purification catalyst | |
| JPH1110003A (en) | Catalyst for purification of waste gas |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090317 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20090317 Year of fee payment: 9 |
|
| FPAY | Renewal fee payment (prs date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100317 Year of fee payment: 10 |
|
| LAPS | Cancellation because of no payment of annual fees |