JPH07233723A - Monolithic catalyst - Google Patents
Monolithic catalystInfo
- Publication number
- JPH07233723A JPH07233723A JP6025338A JP2533894A JPH07233723A JP H07233723 A JPH07233723 A JP H07233723A JP 6025338 A JP6025338 A JP 6025338A JP 2533894 A JP2533894 A JP 2533894A JP H07233723 A JPH07233723 A JP H07233723A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- exhaust gas
- catalyst carrier
- coating material
- gas inflow
- 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
- 239000003054 catalyst Substances 0.000 title claims abstract description 147
- 239000000463 material Substances 0.000 claims abstract description 25
- 239000011248 coating agent Substances 0.000 claims abstract description 24
- 238000000576 coating method Methods 0.000 claims abstract description 24
- 238000002485 combustion reaction Methods 0.000 abstract description 3
- 238000010792 warming Methods 0.000 abstract 1
- 230000004913 activation Effects 0.000 description 12
- 238000000746 purification Methods 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 7
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 4
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 229910052697 platinum Inorganic materials 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229910052703 rhodium Inorganic materials 0.000 description 2
- 239000010948 rhodium Substances 0.000 description 2
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 2
- 239000013585 weight reducing agent Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052878 cordierite Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Classifications
-
- 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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Landscapes
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Catalysts (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、内燃機関から排出され
た排気ガスを浄化する排気ガス浄化触媒に係わり、特
に、触媒成分を担持する担体がモノリス構造であるモノ
リス触媒に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying catalyst for purifying exhaust gas discharged from an internal combustion engine, and more particularly to a monolith catalyst in which a carrier carrying a catalyst component has a monolith structure.
【０００２】[0002]
【従来の技術】従来、自動車の内燃機関より排出された
排気ガスに含まれるＨＣ、ＣＯ、およびＮＯｘ等を浄化
するためモノリス構造の担体の表面に被覆したコート材
へ、白金、ロジウム等の触媒成分を担持させたモノリス
触媒が知られている。一般的に、触媒による排気ガスの
浄化作用には、触媒温度が活性化温度に達することが必
要である。しかし、エンジン始動後等の機関冷間時にお
いては、触媒が活性化温度に達するのに時間がかかり、
長時間にわたり殆ど浄化されない排気ガスが排出される
という問題がある。2. Description of the Related Art Conventionally, a catalyst such as platinum or rhodium is applied to a coating material coated on the surface of a carrier having a monolith structure in order to purify HC, CO, NOx and the like contained in exhaust gas discharged from an internal combustion engine of an automobile. A monolith catalyst supporting a component is known. Generally, the purifying action of exhaust gas by a catalyst requires that the catalyst temperature reach an activation temperature. However, when the engine is cold such as after starting the engine, it takes time for the catalyst to reach the activation temperature,
There is a problem that exhaust gas that is hardly purified for a long time is discharged.
【０００３】そこで、触媒の暖機性能を高め、冷間始動
後の排気浄化性能を向上するために、モノリス構造の担
体の表面を被覆するコート材を排気ガス流入部において
減量したモノリス触媒が、特開昭６４─７９３５号に開
示されている。このモノリス触媒では、排気ガス流入部
のコート材が減量されているので、排気ガス流入部の熱
容量が小さくなり、この部分の昇温時間が短くなって、
暖機性能が向上する。Therefore, in order to improve the warm-up performance of the catalyst and improve the exhaust purification performance after cold start, the monolith catalyst in which the coating material for coating the surface of the carrier having the monolith structure is reduced in the exhaust gas inflow portion, It is disclosed in JP-A-64-7935. In this monolith catalyst, since the coating material in the exhaust gas inflow portion is reduced, the heat capacity of the exhaust gas inflow portion becomes small, and the heating time of this portion becomes short,
Warm-up performance is improved.
【０００４】[0004]
【発明が解決しようとする課題】しかし、上記従来技術
においては、コート材を減量しているので、コート材を
減量した分、多孔質であるコート材の触媒成分を担持す
る表面積も減少するため、担持される触媒成分も減少し
ている。このため、モノリス触媒全体の触媒成分の担持
量が減少し、排気浄化性能が低下するという問題があ
る。本発明は、触媒担持量の減少を招くことなく、排気
ガス流入部の単位体積当たりの熱容量を小さくすること
により触媒の暖機性能を向上させることを目的とする。However, in the above-mentioned prior art, since the amount of the coating material is reduced, the surface area for supporting the catalyst component of the porous coating material is reduced by the amount of the coating material reduced. Also, the amount of supported catalyst components is decreasing. For this reason, there is a problem that the amount of catalyst components carried by the entire monolith catalyst is reduced, and the exhaust gas purification performance is reduced. An object of the present invention is to improve the warm-up performance of the catalyst by reducing the heat capacity per unit volume of the exhaust gas inflow portion without causing a decrease in the amount of catalyst carried.
【０００５】[0005]
【課題を解決するための手段】上記目的を達成するため
の本発明の手段は、以下の構成を備える。触媒担体と、
この触媒担体の表面に略均一に被覆されるコート材と、
このコート材に担持される触媒成分からなるモノリス触
媒において、前記触媒担体の排気ガス流入部の単位体積
当たりの熱容量を排気ガス流出部の単位体積当たりの熱
容量より小さくしたことを特徴とする。Means for Solving the Problems The means of the present invention for achieving the above object comprises the following constitutions. A catalyst carrier,
A coating material that coats the surface of the catalyst carrier substantially uniformly,
In the monolith catalyst composed of the catalyst component supported on the coating material, the heat capacity per unit volume of the exhaust gas inflow portion of the catalyst carrier is smaller than the heat capacity per unit volume of the exhaust gas outflow portion.
【０００６】[0006]
【作用】本発明のモノリス触媒では、触媒担体の排気ガ
ス流入部の単位体積当たりの熱容量が小さくされてい
る。触媒担体の排気ガス流入部には直接排気ガスがあた
り、また排気ガス流入部の単位体積当たりの熱容量は小
さくされているので、排気ガス流入部の触媒温度は急速
に上昇し、短時間で活性化温度に達する。そして、活性
化温度に達した排気ガス流入部の触媒成分が排気ガスの
浄化を開始する。ここで、触媒成分を担持するコート材
は略均一に触媒担体に被覆され、表面積もコート材の量
に応じて十分あり、触媒成分は同様に触媒担体表面に略
均一に担持されるため、結果として触媒担体全体に触媒
成分は略均一に十分担持されるため、触媒成分の減少を
招くことはない。よって、触媒担体の排気ガス流入部で
活性化温度に達した触媒成分により、活発に排気ガスの
浄化反応が行われる。そして、触媒成分の排気ガスを浄
化する際の反応は発熱反応であるため、この触媒担体の
排気ガス流入部での排気ガス浄化による反応熱により、
排気ガス流出部の触媒担体も加熱され、モノリス触媒全
体が短時間のうちに活性化温度に達する。In the monolith catalyst of the present invention, the heat capacity per unit volume of the exhaust gas inflow portion of the catalyst carrier is reduced. Since the exhaust gas directly contacts the exhaust gas inflow part of the catalyst carrier, and the heat capacity per unit volume of the exhaust gas inflow part is small, the catalyst temperature in the exhaust gas inflow part rises rapidly and becomes active in a short time. Reaches the oxidization temperature. Then, the catalyst component in the exhaust gas inflow portion that has reached the activation temperature starts purification of the exhaust gas. Here, the coating material supporting the catalyst component is substantially uniformly coated on the catalyst carrier, and the surface area is sufficient depending on the amount of the coating material, and the catalyst component is also supported substantially uniformly on the surface of the catalyst carrier. As a result, since the catalyst component is supported substantially uniformly and sufficiently on the entire catalyst carrier, the catalyst component is not reduced. Therefore, the exhaust gas purifying reaction is actively performed by the catalyst component that has reached the activation temperature in the exhaust gas inflow portion of the catalyst carrier. Since the reaction when purifying the exhaust gas of the catalyst component is an exothermic reaction, the reaction heat due to the exhaust gas purification at the exhaust gas inflow portion of this catalyst carrier causes
The catalyst carrier in the exhaust gas outflow portion is also heated, and the entire monolith catalyst reaches the activation temperature in a short time.
【０００７】[0007]
【実施例】以下、図面を参照して本発明の実施例を詳細
に説明する。図１に、本発明の第一実施例のモノリス触
媒２の概略図を、また、図２に、第一実施例のモノリス
触媒２の触媒担体３の拡大断面図を示し説明する。図１
において、モノリス触媒２は、直径１０．７cm、長さ１
５cmのもので、ステンレス等の金属からなる触媒ケース
１内に、図示しないクッション材等を介して固定され
る。モノリス触媒２は、図２に示すように、アルミ含有
フェライト等からなるハニカム構造の触媒担体３と、こ
の触媒担体３の表面に均一に被覆される活性アルミナ等
からなるコート材５から構成されている。コート材５に
は、白金、ロジウム、またはパラジウム等からなる触媒
成分６が担持されている。Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a schematic view of the monolith catalyst 2 of the first embodiment of the present invention, and FIG. 2 shows an enlarged cross-sectional view of the catalyst carrier 3 of the monolith catalyst 2 of the first embodiment. Figure 1
In, the monolith catalyst 2 has a diameter of 10.7 cm and a length of 1
It is 5 cm in length, and is fixed in a catalyst case 1 made of metal such as stainless steel via a cushion material (not shown). As shown in FIG. 2, the monolith catalyst 2 is composed of a honeycomb-structured catalyst carrier 3 made of aluminum-containing ferrite or the like, and a coating material 5 made of activated alumina or the like to uniformly coat the surface of the catalyst carrier 3. There is. A catalyst component 6 made of platinum, rhodium, palladium or the like is carried on the coating material 5.
【０００８】図２のハニカム構造の触媒担体３におい
て、排気ガス流入側の端部から１．５cmまでの排気ガス
流入部の肉厚ｔ1'は、触媒担体３の中央部から排気ガス
流出部までの肉厚ｔ1 より薄くなっている。よって、触
媒担体３の排気ガス流入部の肉厚が薄く、単位体積当た
りの熱容量が小さくなることから、排気ガス流入部の昇
温性能が向上し、エンジン始動後等の機関冷間時であっ
ても、始動後まもなく排気ガス流入部の触媒成分が触媒
活性化温度に達する。触媒成分６を担持する多孔質層の
コート材５は略均一に触媒担体に被覆され、表面積もコ
ート材５の量に応じて十分あり、触媒成分６は同様に触
媒担体３表面に略均一に担持されるため、結果として触
媒担体３全体に触媒成分は略均一に十分担持されるた
め、触媒成分の減少を招くことはない。触媒担体３の活
性化温度に達した排気ガス流入部の触媒成分６により、
活発に排気ガスの浄化反応が行われる。また、触媒担体
３の排気ガス流入部の肉厚ｔ1'を薄くし、排気ガス流出
部側に行くにしたがって徐々に厚くしたので、触媒担体
３の入口での通路断面積変化がなだらかになり、排気通
路内を流れる排気ガスの通路抵抗（圧力損失）を低く抑
えられるため、エンジンの出力向上にも役立つ。In the honeycomb-structured catalyst carrier 3 shown in FIG. 2, the thickness t 1 ′ of the exhaust gas inflow portion up to 1.5 cm from the end on the exhaust gas inflow side is from the central portion of the catalyst carrier 3 to the exhaust gas outflow portion. Is thinner than the wall thickness t 1 up to. Therefore, since the thickness of the exhaust gas inflow portion of the catalyst carrier 3 is thin and the heat capacity per unit volume is small, the temperature raising performance of the exhaust gas inflow portion is improved, and the engine is cold after the engine is started. However, the catalyst component in the exhaust gas inflow portion reaches the catalyst activation temperature shortly after the start. The coating material 5 of the porous layer supporting the catalyst component 6 is substantially evenly coated on the catalyst carrier, and the surface area is sufficient depending on the amount of the coating material 5, and the catalyst component 6 is also substantially uniformly distributed on the surface of the catalyst carrier 3. As a result, the catalyst components are supported substantially uniformly and sufficiently on the entire catalyst carrier 3, so that the catalyst components are not reduced. By the catalyst component 6 in the exhaust gas inflow portion that has reached the activation temperature of the catalyst carrier 3,
Exhaust gas purification reaction is actively performed. Further, since the thickness t 1 ′ of the exhaust gas inflow portion of the catalyst carrier 3 is thinned and gradually increased toward the exhaust gas outflow portion side, the passage cross-sectional area change at the inlet of the catalyst carrier 3 becomes gentle. Since the passage resistance (pressure loss) of the exhaust gas flowing in the exhaust passage can be kept low, it is also useful for improving the engine output.
【０００９】ここで、触媒担体３の温度が上昇すると、
温度差が生じる部位には熱膨張による膨張量の差により
大きな応力が生じ、装置が破損する場合がある。しか
し、触媒担体３の排気ガス流入部の温度は、随時流入す
る排気ガスの温度により支配されるため、排気ガス浄化
による反応熱の影響を受ける排気ガス流出部に比べ、比
較的安定しており、異常過熱されることはない。よっ
て、触媒担体３の排気ガス流入部の熱膨張による応力
は、触媒担体３の中央部から排気ガス流出部にかけての
熱膨張による応力よりも比較的小さくなるため、第一実
施例のような排気ガス流入部では触媒担体３の肉厚ｔ1'
を薄く、また排気ガス流出部では触媒担体３の肉厚ｔ1
は比較的厚くすることにより、熱による応力に対しても
適切に対応した構造となっている。Here, if the temperature of the catalyst carrier 3 rises,
A large stress may be generated at a portion where a temperature difference occurs due to a difference in expansion amount due to thermal expansion, and the device may be damaged. However, since the temperature of the exhaust gas inflow portion of the catalyst carrier 3 is controlled by the temperature of the exhaust gas that flows in at any time, it is relatively stable as compared with the exhaust gas outflow portion that is affected by the reaction heat due to exhaust gas purification. , Will not be overheated abnormally. Therefore, the stress due to the thermal expansion of the exhaust gas inflow portion of the catalyst carrier 3 is relatively smaller than the stress due to the thermal expansion from the central portion of the catalyst carrier 3 to the exhaust gas outflow portion. At the gas inflow portion, the thickness t 1 'of the catalyst carrier 3
And the thickness t 1 of the catalyst carrier 3 at the exhaust gas outflow portion
Has a structure that appropriately responds to the stress due to heat by making it relatively thick.
【００１０】図３に本発明の第二実施例におけるモノリ
ス触媒の触媒担体１３の拡大断面図を示し説明する。第
二実施例の触媒担体１３も第一実施例と同様、ケース内
にクッション材等を介して固定される。ハニカム構造の
触媒担体１３の排気ガス流入部の表面にモノリス触媒２
の一つのセル４の大きさよりかなり細かいディンプル状
の凹部１７を複数設ける。このことにより、排気ガス流
入部の触媒担体１３が軽量になり単位体積当たりの熱容
量を低く抑えることができるため、第一実施例と同様
に、排気ガス流入部の触媒担体１３の昇温性能が向上
し、エンジン始動後等の機関冷間時の暖機性能を向上さ
せることができる。また、触媒成分１６を担持する多孔
質層のコート材１５は略均一に触媒担体１３に被覆さ
れ、表面積もコート材１５の量に応じて十分あり、触媒
成分１６は同様に触媒担体１３の表面に略均一に担持さ
れるため、結果として触媒担体１３全体に触媒成分１６
は略均一に十分担持されるため、触媒成分１６の減少を
招くことがない。よって、エンジン始動後まもなく活性
化温度に達した触媒担体１３の排気ガス流入部の触媒成
分１６により、排気ガスが浄化される。また、第一実施
例と同様に触媒担体１３の排気ガス流入部の排気ガス浄
化による反応熱により排気ガス通路下流側の触媒担体１
３も加熱され、モノリス触媒全体も短時間のうちに活性
化温度に達する。FIG. 3 shows an enlarged sectional view of the catalyst carrier 13 of the monolith catalyst according to the second embodiment of the present invention. Similarly to the first embodiment, the catalyst carrier 13 of the second embodiment is also fixed in the case via a cushion material or the like. The monolith catalyst 2 is formed on the surface of the exhaust gas inflow portion of the catalyst carrier 13 having a honeycomb structure.
A plurality of dimple-shaped recesses 17 that are considerably smaller than the size of one cell 4 are provided. As a result, the catalyst carrier 13 in the exhaust gas inflow portion becomes light in weight and the heat capacity per unit volume can be suppressed to a low level, so that the temperature raising performance of the catalyst carrier 13 in the exhaust gas inflow portion can be reduced as in the first embodiment. It is possible to improve the warm-up performance when the engine is cold after the engine is started. Further, the coating material 15 of the porous layer carrying the catalyst component 16 is substantially evenly coated on the catalyst carrier 13, and the surface area is sufficient depending on the amount of the coating material 15, and the catalyst component 16 similarly has the surface of the catalyst carrier 13. As a result, the catalyst components 16 are substantially evenly supported on the entire catalyst carrier 13.
Is substantially uniformly and sufficiently supported, so that the catalyst component 16 does not decrease. Therefore, the exhaust gas is purified by the catalyst component 16 in the exhaust gas inflow portion of the catalyst carrier 13 that has reached the activation temperature shortly after the engine is started. Further, as in the first embodiment, the catalyst carrier 1 on the downstream side of the exhaust gas passage is formed by the reaction heat of the exhaust gas purification of the exhaust gas inflow portion of the catalyst carrier 13.
3 is also heated, and the entire monolith catalyst reaches the activation temperature in a short time.
【００１１】また細かいディンプル状の凹部１７により
触媒担体１３の表面を流れる排気ガスの流れに乱れを起
こすことができる。よって、触媒担体１３上の触媒成分
１６への排気ガスの衝突回数を増加させることができ、
触媒成分１６の単位質量当たりの排気ガス浄化率の向上
が可能となるため、モノリス触媒全体の大きさを縮小す
ることが可能となり、軽量化、コスト削減、および、早
期浄化率向上に役立つ。Further, the fine dimple-shaped recesses 17 can cause turbulence in the flow of exhaust gas flowing on the surface of the catalyst carrier 13. Therefore, the number of collisions of the exhaust gas with the catalyst component 16 on the catalyst carrier 13 can be increased,
Since the exhaust gas purification rate per unit mass of the catalyst component 16 can be improved, the size of the entire monolith catalyst can be reduced, which is useful for weight reduction, cost reduction, and early purification rate improvement.
【００１２】また、コージェライト等のセラミック触媒
担体のように触媒担体の排気流入部の内部に気孔部を有
するものであれば、気孔部の触媒担体に対する割合を示
す気孔率において、触媒担体の排気ガス流入部の気孔率
を排気ガス流出部の気孔率より大きくすることにより、
同様に排気ガス流入部の単位体積当たりの熱容量を低く
抑えることがでる。従って、排気ガス流入部の昇温性能
が向上し、暖機性能が向上できる。また、上記実施例で
は一つのモノリス触媒により構成しているが、排気ガス
流入部と排気ガス流出部とで別々のモノリス触媒にて構
成してもよい。また、上記モノリス触媒の暖機性能が向
上することにより、エンジン始動後等の機関冷間時にお
いて、排気ガスは浄化されずに排出されるものがかなり
抑制できるため、従来、使用されていた暖機時の浄化能
力を向上させるためスタートアップコンバータ等の余分
な量の触媒を廃止でき、モノリス触媒を必要な量だけに
とどめておくことが可能となり、コスト削減や軽量化に
も役立つ。Further, in the case of a ceramic catalyst carrier such as cordierite, which has pores inside the exhaust inflow portion of the catalyst carrier, the exhaust of the catalyst carrier at the porosity indicating the ratio of the pores to the catalyst carrier. By making the porosity of the gas inflow part larger than the porosity of the exhaust gas outflow part,
Similarly, the heat capacity per unit volume of the exhaust gas inflow portion can be kept low. Therefore, the temperature rising performance of the exhaust gas inflow portion is improved, and the warm-up performance can be improved. Further, in the above embodiment, one monolith catalyst is used, but the exhaust gas inflow portion and the exhaust gas outflow portion may be configured with different monolith catalysts. Further, since the warm-up performance of the monolith catalyst is improved, exhaust gas without being purified can be considerably suppressed when the engine is cold such as after the engine is started. In order to improve the purification capacity at the time of use, it is possible to abolish an excessive amount of catalyst such as a start-up converter, and it is possible to keep the monolith catalyst only in a necessary amount, which is also useful for cost reduction and weight reduction.
【００１３】[0013]
【発明の効果】本発明のモノリス触媒では、排気管上流
側より流れてくる排気ガスが直接当たるモノリス触媒の
触媒担体の排気ガス流入部において、触媒担体の単位体
積当たりの熱容量を小さくしたので、昇温性能が向上し
エンジン始動後短時間で排気ガス流入部の触媒成分が活
性化温度に達する。触媒成分を担持する多孔質層のコー
ト材は略均一に触媒担体に被覆され、表面積もコート材
の量に応じて十分あり、触媒成分は同様に触媒担体表面
に略均一に担持されるため、結果として触媒担体全体に
触媒成分は略均一に十分担持されるため、触媒成分の減
少を招くことはない。よって、短時間で活性化温度に達
した触媒担体の排気ガス流入部の触媒成分が排気ガスの
浄化を開始する。この触媒担体の排気ガス流入部の発熱
により、排気ガス流出部の触媒担体も加熱され、モノリ
ス触媒全体が短時間のうちに活性化温度に達する。よっ
て、従来技術と比べより早くエンジン始動後のモノリス
触媒の浄化率を高くすることができる。According to the monolith catalyst of the present invention, the heat capacity per unit volume of the catalyst carrier is reduced in the exhaust gas inflow portion of the catalyst carrier of the monolith catalyst, which is directly hit by the exhaust gas flowing from the exhaust pipe upstream side. The temperature raising performance is improved, and the catalyst components in the exhaust gas inflow portion reach the activation temperature in a short time after the engine is started. The coating material of the porous layer supporting the catalyst component is substantially uniformly coated on the catalyst carrier, the surface area is sufficient depending on the amount of the coating material, and the catalyst component is also supported substantially uniformly on the catalyst carrier surface. As a result, the catalyst component is supported substantially uniformly and sufficiently on the entire catalyst carrier, so that the catalyst component is not reduced. Therefore, the catalyst component in the exhaust gas inflow portion of the catalyst carrier, which has reached the activation temperature in a short time, starts purification of the exhaust gas. The heat generated in the exhaust gas inflow portion of the catalyst carrier also heats the catalyst carrier in the exhaust gas outflow portion, and the entire monolith catalyst reaches the activation temperature in a short time. Therefore, the purification rate of the monolith catalyst after the engine is started can be increased faster than in the conventional technique.
【図１】 第一実施例のモノリス触媒の概略図FIG. 1 is a schematic view of a monolith catalyst according to a first embodiment.
【図２】 第一実施例におけるモノリス触媒の触媒
担体の拡大断面図FIG. 2 is an enlarged sectional view of a catalyst carrier of a monolith catalyst according to the first embodiment.
【図３】 第二実施例におけるモノリス触媒の触媒
担体の拡大断面図FIG. 3 is an enlarged sectional view of a catalyst carrier of a monolith catalyst according to a second embodiment.
１ ・・・ 触媒ケース ２ ・・・ モノリス触媒 ３、１３ ・・・ 触媒担体 ４ ・・・ セル ５、１５ ・・・ コート材 ６、１６ ・・・ 触媒成分 １７ ・・・ ディンプル状凹部 ｔ1 、ｔ2 ・・・ 排気ガス流出部の触媒担体の肉厚 ｔ1'、ｔ2'・・・ 排気ガス流入部の触媒担体の薄い部
分の肉厚1 ... Catalyst case 2 ... Monolith catalyst 3, 13 ... Catalyst carrier 4 ... Cell 5, 15 ... Coating material 6, 16 ... Catalyst component 17 ... Dimple-shaped recess t 1 , T 2 ... Thickness of catalyst carrier at exhaust gas outflow portion t 1 ', t 2 ' ... Thickness of thin portion of catalyst carrier at exhaust gas inflow portion
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｂ０１Ｊ 35/02 ３０１ Ｂ Ｆ０１Ｎ 3/20 ＺＡＢ Ｄ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 6 Identification code Internal reference number FI Technical display location B01J 35/02 301 B F01N 3/20 ZAB D
Claims (1)
に被覆されるコート材と、該コート材に担持される触媒
成分からなるモノリス触媒において、前記触媒担体の排
気ガス流入部の単位体積当たりの熱容量を排気ガス流出
部の単位体積当たりの熱容量より小さくしたことを特徴
とするモノリス触媒。1. A unit of an exhaust gas inflow portion of a catalyst carrier, which comprises a catalyst carrier, a coating material coated on the surface of the catalyst carrier substantially uniformly, and a catalyst component carried by the coating material. A monolith catalyst characterized in that the heat capacity per volume is made smaller than the heat capacity per unit volume of the exhaust gas outflow portion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6025338A JPH07233723A (en) | 1994-02-23 | 1994-02-23 | Monolithic catalyst |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6025338A JPH07233723A (en) | 1994-02-23 | 1994-02-23 | Monolithic catalyst |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07233723A true JPH07233723A (en) | 1995-09-05 |
Family
ID=12163133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6025338A Pending JPH07233723A (en) | 1994-02-23 | 1994-02-23 | Monolithic catalyst |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07233723A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8273315B2 (en) | 2010-08-09 | 2012-09-25 | Ford Global Technologies, Llc | Engine emission control system |
-
1994
- 1994-02-23 JP JP6025338A patent/JPH07233723A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8273315B2 (en) | 2010-08-09 | 2012-09-25 | Ford Global Technologies, Llc | Engine emission control system |
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