JPH0814029A - Exhaust emission control device for internal combustion engine - Google Patents
Exhaust emission control device for internal combustion engineInfo
- Publication number
- JPH0814029A JPH0814029A JP6142953A JP14295394A JPH0814029A JP H0814029 A JPH0814029 A JP H0814029A JP 6142953 A JP6142953 A JP 6142953A JP 14295394 A JP14295394 A JP 14295394A JP H0814029 A JPH0814029 A JP H0814029A
- Authority
- JP
- Japan
- Prior art keywords
- catalyst
- exhaust gas
- platinum
- internal combustion
- palladium
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
- B01D53/945—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific catalyst
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
- B01D53/9454—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific device
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9495—Controlling the catalytic process
-
- 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
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
-
- 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
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/18—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control
- F01N3/20—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by methods of operation; Control specially adapted for catalytic conversion ; Methods of operation or control of catalytic converters
-
- 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
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
- F01N3/28—Construction of catalytic reactors
-
- 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
-
- 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
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Health & Medical Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Biomedical Technology (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Toxicology (AREA)
- Exhaust Gas After Treatment (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は内燃機関の排気ガス浄化
装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying device for an internal combustion engine.
【０００２】[0002]
【従来の技術】従来より排気ガスの浄化性能を高めるた
めに三元触媒や酸化触媒を種々に組合せて機関排気通路
内に配置することが行われている。例えば特開平４−２
８７８２０号公報に記載された内燃機関では白金に加
え、耐熱性がありかつ強い酸化力を有するパラジウムを
含んだ酸化触媒を機関の排気ガス出口に配置し、この酸
化触媒下流の排気通路内に三元触媒を配置している。三
元触媒は一般的に耐熱性に乏しく、従って温度の低下し
た排気ガスが三元触媒に流入するように三元触媒は機関
の排気ガス出口から離れた機関排気通路内に配置され
る。ところがこのように三元触媒を機関の排気ガス出口
から離れたところに配置すると機関始動後三元触媒が活
性化するまでに時間を要し、斯くしてこの間、排気ガス
を浄化することができないという問題を生ずる。2. Description of the Related Art Conventionally, various combinations of a three-way catalyst and an oxidation catalyst have been arranged in an engine exhaust passage in order to improve exhaust gas purification performance. For example, Japanese Patent Laid-Open No. 4-2
In the internal combustion engine described in Japanese Patent No. 87820, in addition to platinum, an oxidation catalyst containing palladium, which is heat resistant and has a strong oxidizing power, is arranged at the exhaust gas outlet of the engine, and three catalysts are provided in the exhaust passage downstream of the oxidation catalyst. The original catalyst is placed. The three-way catalyst is generally poor in heat resistance, so that the three-way catalyst is arranged in the engine exhaust passage away from the exhaust gas outlet of the engine so that the exhaust gas having a lowered temperature flows into the three-way catalyst. However, if the three-way catalyst is placed away from the exhaust gas outlet of the engine in this way, it takes time for the three-way catalyst to be activated after the engine is started, and therefore the exhaust gas cannot be purified during this time. The problem arises.
【０００３】そこで上述の内燃機関では高温の排気ガス
が流出する機関排気ガス出口に酸化触媒を配置し、この
酸化触媒を機関始動後すみやかに活性化させて機関始動
後すみやかにＨＣの酸化反応を開始させ、この酸化反応
熱によって三元触媒を早期に活性化させるようにしてい
る。また、この内燃機関ではＨＣの浄化は酸化触媒によ
って行い、ＣＯおよびＮＯｘの浄化は三元触媒により行
うようにして触媒毎に浄化作用の役割りを分担させるよ
うにしている。Therefore, in the above-mentioned internal combustion engine, an oxidation catalyst is arranged at the outlet of the engine exhaust gas from which high-temperature exhaust gas flows, and this oxidation catalyst is activated immediately after the engine is started to promptly carry out the oxidation reaction of HC after the engine is started. The catalyst is started and the three-way catalyst is activated early by this heat of oxidation reaction. Further, in this internal combustion engine, purification of HC is carried out by an oxidation catalyst, and purification of CO and NOx is carried out by a three-way catalyst so that each catalyst plays a role of a purifying action.
【０００４】一方、特開昭６２−１３６２４５号公報に
記載された内燃機関では排気マニホルドの出口に上流側
触媒を配置し、この上流側触媒下流の排気通路内に三元
触媒を配置している。一個の三元触媒によりＣＯ，ＮＯ
ｘ等を十分に浄化するのは困難であり、従ってこの内燃
機関では酸化機能を有するパラジウムに加え、酸化還元
機能、即ち三元機能を有する白金とロジウムを上流側触
媒の担体に担持させ、上流側触媒に酸化機能に加えて三
元機能をも同時に持たせるようにしている。On the other hand, in the internal combustion engine disclosed in Japanese Patent Laid-Open No. 62-136245, an upstream catalyst is arranged at the outlet of the exhaust manifold, and a three-way catalyst is arranged in the exhaust passage downstream of the upstream catalyst. . CO, NO with one three-way catalyst
It is difficult to sufficiently purify x and the like. Therefore, in this internal combustion engine, in addition to palladium having an oxidizing function, platinum and rhodium having a redox function, that is, a ternary function are supported on the carrier of the upstream side catalyst, In addition to the oxidizing function, the side catalyst also has a three-way function.
【０００５】また、特開平４−１１８０５３号公報に記
載された内燃機関では４個の触媒を機関排気通路内に直
列に配置し、真中の２個の触媒を白金およびロジウムを
含んだ三元触媒から形成すると共に各触媒担体の排気ガ
ス流入側端部領域にパラジウムが高濃度で分布されてい
る。この内燃機関ではパラジウムによって触媒に流入す
る排気ガス中のＨＣ，ＣＯの酸化反応が促進され、この
ときの酸化反応熱によって触媒全体が早期に活性化せし
められる。Further, in the internal combustion engine described in JP-A-4-118053, four catalysts are arranged in series in an engine exhaust passage, and two catalysts in the middle are three-way catalysts containing platinum and rhodium. And palladium is distributed at a high concentration in the exhaust gas inflow side end region of each catalyst carrier. In this internal combustion engine, the oxidation reaction of HC and CO in the exhaust gas flowing into the catalyst is promoted by the palladium, and the heat of the oxidation reaction at this time activates the entire catalyst early.
【０００６】[0006]
【発明が解決しようとする課題】ところでパラジウムを
用いてＨＣを酸化させ、その後三元触媒においてＮＯｘ
の還元作用を強力に推進させるようにした場合には三元
触媒の担体上に担持すべき触媒としては白金とロジウム
が好ましいことが知られている。また、三元触媒による
ＨＣ，ＣＯ，ＮＯｘの浄化効率は混合気の空燃比が理論
空燃比となったときに最も高くなることが知られてお
り、従って三元触媒を用いたときには空燃比が理論空燃
比となるように制御される。また、このとき三元触媒の
担体上にセリウムを担持させるとＨＣ，ＣＯ，ＮＯｘの
浄化効率が一層高くなることが知られている。However, palladium is used to oxidize HC, and then NOx is used in a three-way catalyst.
It is known that platinum and rhodium are preferable as the catalyst to be supported on the carrier of the three-way catalyst when the reduction action of is strongly promoted. Further, it is known that the purification efficiency of HC, CO, and NOx by the three-way catalyst becomes highest when the air-fuel ratio of the air-fuel mixture becomes the stoichiometric air-fuel ratio. Therefore, when the three-way catalyst is used, the air-fuel ratio becomes The stoichiometric air-fuel ratio is controlled. Further, it is known that when cerium is carried on the carrier of the three-way catalyst at this time, the purification efficiency of HC, CO, and NOx is further enhanced.
【０００７】即ち、内燃機関においては通常、排気通路
内に設けた空燃比センサの出力信号に基き空燃比をフィ
ードバック制御することにより空燃比が理論空燃比に制
御される。この場合、実際には空燃比は理論空燃比を境
にしてリーン側とリッチ側に交互に変動する。ところで
セリウムは空燃比がリーンになったときには排気ガス中
の酸素を取込んでＮＯｘを浄化し、空燃比がリッチにな
ったときには取込んだ酸素を放出して未燃ＨＣ，ＣＯを
浄化する機能を有しており、セリウムによるこのような
酸素のストレージ作用によってＨＣ，ＣＯ，ＮＯｘの浄
化作用が促進される。従ってセリウムを添加するとＨ
Ｃ，ＣＯ，ＮＯｘの浄化効率が向上することになる。That is, in an internal combustion engine, the air-fuel ratio is usually controlled to the stoichiometric air-fuel ratio by feedback-controlling the air-fuel ratio based on the output signal of the air-fuel ratio sensor provided in the exhaust passage. In this case, the air-fuel ratio actually fluctuates alternately between the lean side and the rich side with the stoichiometric air-fuel ratio as the boundary. Cerium takes in oxygen in the exhaust gas to purify NOx when the air-fuel ratio becomes lean, and releases the taken-in oxygen to purify unburned HC and CO when the air-fuel ratio becomes rich. The storage action of oxygen by cerium promotes the purification action of HC, CO, and NOx. Therefore, if cerium is added, H
The purification efficiency of C, CO, and NOx will be improved.
【０００８】ところで下流側に設けられた一つの三元触
媒だけでは特にＮＯｘを十分に浄化するのは困難であ
り、従って上流側に設けられた触媒の担体には酸化反応
を促進するパラジウムに加え、特にＮＯｘに対して強い
還元性を示す白金およびロジウムを担持させることが好
ましいことになる。従って前述したように特開昭６２−
１３６２４５号公報に記載された内燃機関では上流側触
媒の担体上にパラジウム、白金およびロジウムを担持さ
せるようにしている。ところがこの内燃機関ではパラジ
ウム、白金およびロジウムが触媒全体に分散されてお
り、このようにパラジウム、白金、ロジウムを触媒全体
に分散させると特に白金が劣化してしまうという問題を
生ずる。By the way, it is difficult to sufficiently purify NOx particularly with only one three-way catalyst provided on the downstream side. Therefore, in addition to palladium, which promotes the oxidation reaction, is added to the carrier of the catalyst provided on the upstream side. In particular, it is preferable to support platinum and rhodium, which have a strong reducing property for NOx. Therefore, as described above, JP-A-62-1
In the internal combustion engine described in Japanese Patent No. 136245, palladium, platinum and rhodium are carried on the carrier of the upstream side catalyst. However, in this internal combustion engine, palladium, platinum, and rhodium are dispersed throughout the catalyst, and when palladium, platinum, and rhodium are dispersed throughout the catalyst in this way, there arises a problem that platinum is particularly deteriorated.
【０００９】即ち、上流側触媒は高温の排気ガスにさら
されるために高温となる。また、三元触媒を用いている
ために空燃比は交互にリーンとリッチにされ、斯くして
上流側触媒に流入する排気ガスは周期的に酸素過剰な状
態となる。ところが白金Ｐｔは高温下で酸素が過剰にな
ると酸化白金ＰｔＯ2 となり、次いで酸化白金ＰｔＯ 2
同志が互いに合体して粒成長し、大きな粒子になってし
まう。大きな粒子になると表面積が減少するために触媒
機能が低下し、斯くして白金が劣化することになる。即
ち、白金を上流側触媒に分散させると白金が劣化するこ
とになり、斯くして白金、ロジウムによる酸化還元力が
弱まることになる。That is, the upstream side catalyst is exposed to high temperature exhaust gas.
Therefore, the temperature becomes high. It also uses a three-way catalyst.
The air-fuel ratio is alternately made lean and rich in order to
Exhaust gas flowing into the upstream side catalyst is periodically in excess of oxygen.
It becomes a state. However, platinum Pt has excess oxygen at high temperature.
And platinum oxide PtO2And then platinum oxide PtO 2
Comrades coalesce with each other and grow into large particles.
I will Catalysts due to the decrease in surface area with larger particles
The function is deteriorated and thus platinum is deteriorated. Immediately
However, if platinum is dispersed in the upstream catalyst, platinum will deteriorate.
Therefore, the redox power of platinum and rhodium is
Will be weakened.
【００１０】一方、特開平４−２８７８２０号公報に記
載された内燃機関でも上流側に設けられた酸化触媒の担
体にパラジウムおよび白金が分散されている。この内燃
機関においても酸化触媒は高温となり酸化触媒に流入す
る排気ガスは周期的に酸素過剰な状態となるので白金が
劣化してしまうことになる。また、特開平４−１１８０
５３号公報に記載されている内燃機関ではパラジウムは
触媒担体の排気ガス流入側端部領域に集中して担持され
ているが白金は触媒担体の全体に分散せしめられてい
る。排気ガス中の酸素はパラジウムによる酸化作用のた
めに使用されるので排気ガス流入側端部領域よりも下流
の触媒領域に流入する排気ガス中の酸素量は少なく、斯
くしてこの触媒領域内の白金は酸素が不十分なために粒
成長せず、斯くして白金は劣化しないことになる。とこ
ろが排気ガス流入側端部領域内の白金の周りには十分な
酸素が存在し、斯くしてこの排気ガス流入側端部領域内
の白金が劣化してしまうという問題を生ずる。On the other hand, in the internal combustion engine described in Japanese Patent Laid-Open No. 4-287820, palladium and platinum are dispersed in the carrier for the oxidation catalyst provided on the upstream side. Even in this internal combustion engine, the temperature of the oxidation catalyst becomes high, and the exhaust gas flowing into the oxidation catalyst periodically becomes excessive in oxygen, so that platinum is deteriorated. In addition, Japanese Patent Laid-Open No. 4-1180
In the internal combustion engine disclosed in Japanese Patent No. 53, palladium is concentrated and carried on the exhaust gas inflow side end region of the catalyst carrier, but platinum is dispersed throughout the catalyst carrier. Since the oxygen in the exhaust gas is used for the oxidizing action of palladium, the amount of oxygen in the exhaust gas flowing into the catalyst region downstream of the end region of the exhaust gas inflow side is small, thus Platinum does not grow due to insufficient oxygen, and thus platinum does not deteriorate. However, sufficient oxygen exists around platinum in the exhaust gas inflow side end region, which causes a problem that platinum in the exhaust gas inflow side end region deteriorates.
【００１１】更にこの内燃機関では白金ばかりでなくパ
ラジウムも劣化してしまう。即ち、パラジウムは白金と
は異なり、排気ガス中の酸素が過剰のときには安定な酸
化パラジウムＰｄＯとなり、排気ガス中の酸素が少なく
なると還元されて不安定なパラジウムＰｄの金属単体と
なる。排気ガス中の酸素が周期的に過剰になるとその都
度パラジウムＰｄは酸化パラジウムＰｄＯになるために
粒成長することはないが排気ガス中の酸素が少ない状態
が継続するとパラジウムＰｄの金属単体同志が合体して
粒成長し、斯くしてパラジウムが劣化してしまうことに
なる。Further, in this internal combustion engine, not only platinum but also palladium is deteriorated. That is, unlike platinum, palladium becomes stable palladium oxide PdO when the oxygen in the exhaust gas is excessive, and is reduced when oxygen in the exhaust gas is reduced to become an unstable metal element of palladium Pd. When oxygen in the exhaust gas becomes excessive periodically, palladium Pd becomes palladium oxide PdO each time, so grain growth does not occur, but if the oxygen in the exhaust gas remains low, the metallic elements of palladium Pd will unite. As a result, grains grow and the palladium deteriorates.
【００１２】即ち、この内燃機関では排気ガス流入側端
部領域内の触媒担体上には白金、ロジウムに加えてセリ
ウムが担持されている。このセリウムは前述したように
酸素のストレージ機能があり、酸素が過剰になると酸素
を取込み、酸素がなくなると酸素を放出する。放出され
た酸素はＨＣ，ＣＯの酸化反応に即座に使用される。従
ってセリウムが存在すると排気ガス流入側端部領域では
排気ガス中の酸素が少ない状態が継続することになり、
斯くしてパラジウムが粒成長してパラジウムが劣化する
ことになる。このようにこの内燃機関では白金ばかりで
なく、パラジウムも劣化してしまうという問題がある。That is, in this internal combustion engine, cerium is carried in addition to platinum and rhodium on the catalyst carrier in the exhaust gas inflow side end region. As described above, this cerium has a storage function of oxygen, and takes in oxygen when oxygen becomes excessive, and releases oxygen when oxygen runs out. The released oxygen is immediately used for the oxidation reaction of HC and CO. Therefore, if cerium is present, the exhaust gas inflow side end region will continue to have a small amount of oxygen in the exhaust gas,
As a result, palladium grows and the palladium deteriorates. As described above, in this internal combustion engine, not only platinum but also palladium is deteriorated.
【００１３】[0013]
【課題を解決するための手段】上記問題点を解決するた
めに本発明によれば、機関の排気通路内に排気ガス浄化
用触媒を配置し、排気通路内に設けた空燃比センサの出
力信号に基いて空燃比をほぼ理論空燃比に維持するよう
にした内燃機関において、触媒担体の排気ガス流入側端
部領域のみにパラジウムを担持させると共に排気ガス流
入側端部領域下流側の残りの触媒担体領域のみに白金お
よびロジウムを担持させ、排気ガス流入側端部領域の触
媒担体上にはセリウムを担持させないようにしている。In order to solve the above problems, according to the present invention, an exhaust gas purifying catalyst is arranged in the exhaust passage of an engine, and an output signal of an air-fuel ratio sensor provided in the exhaust passage. In an internal combustion engine in which the air-fuel ratio is maintained substantially at the stoichiometric air-fuel ratio based on the above, palladium is supported only on the exhaust gas inflow side end region of the catalyst carrier and the remaining catalyst on the downstream side of the exhaust gas inflow side end region. Platinum and rhodium are supported only in the carrier region, and cerium is not supported on the catalyst carrier in the exhaust gas inflow side end region.
【００１４】また、本発明によれば上記問題点を解決す
るために上記１番目の発明において、触媒担体にはその
全体に亘って全くセリウムを担持させないようにしてい
る。また、本発明によれば上記問題点を解決するために
上記１番目の発明において、触媒下流の排気通路内にセ
リウムを含んだ三元触媒を配置している。また、本発明
によれば上記問題点を解決するために上記１番目の発明
において、排気ガス流入側端部領域の触媒担体に担持さ
れたパラジウムの量を１気筒の排気量１リットル当り
１．０グラム以上とされる。Further, according to the present invention, in order to solve the above problems, in the first invention, the catalyst carrier is made not to carry cerium at all over the whole. According to the present invention, in order to solve the above-mentioned problems, in the first invention, a three-way catalyst containing cerium is arranged in the exhaust passage downstream of the catalyst. According to the present invention, in order to solve the above problems, in the first invention, the amount of palladium carried on the catalyst carrier in the exhaust gas inflow side end region is 1. It is considered to be 0 grams or more.
【００１５】[0015]
【作用】１番目の発明では排気ガス流入側端部領域の触
媒担体に担持されたパラジウムによって主にＨＣが酸化
される。この排気ガス流入側端部領域の触媒担体上には
セリウムが担持されていないので排気ガス流入側端部領
域内を流れる排気ガス中の酸素は周期的に過剰となり、
従ってパラジウムは劣化し難い。また、排気ガス流入側
端部領域の触媒担体上には白金およびロジウムが担持さ
れておらず、従って排気ガス流入側端部領域内を流れる
排気ガス中の酸素が周期的に過剰になっても白金の劣化
問題は生じない。排気ガス中の過剰酸素はパラジウムに
よる酸化反応に使用されるので排気ガス流入側端部領域
下流の残りの触媒担体領域に流入する排気ガス中の酸素
量は少なく、従ってこの触媒担体領域に担持されている
白金は劣化し難い。In the first aspect of the invention, HC is mainly oxidized by the palladium carried on the catalyst carrier in the exhaust gas inflow side end region. Since cerium is not supported on the catalyst carrier in the exhaust gas inflow side end region, oxygen in the exhaust gas flowing in the exhaust gas inflow side end region becomes periodically excessive,
Therefore, palladium is unlikely to deteriorate. Further, platinum and rhodium are not supported on the catalyst carrier in the exhaust gas inflow side end region, so that even if the oxygen in the exhaust gas flowing in the exhaust gas inflow side end region becomes periodically excessive. The problem of platinum deterioration does not occur. Since the excess oxygen in the exhaust gas is used for the oxidation reaction by palladium, the amount of oxygen in the exhaust gas flowing into the remaining catalyst carrier region downstream of the end region of the exhaust gas inflow side is small, and thus is supported in this catalyst carrier region. Platinum is hard to deteriorate.
【００１６】２番目の発明では排気ガス流入側端部領域
下流の残りの触媒担体領域にもセリウムを担持させない
ようにしている。３番目の発明ではセリウムを含ませる
ことによって酸化還元能力の高められた三元触媒が１番
目の発明に記載された触媒の下流に配置される。４番目
の発明では良好な酸化反応を確保するために排気ガス流
入側端部領域の触媒担体に担持されたパラジウムの量が
１気筒の排気量１リットル当り１．０グラム以上とされ
る。In the second aspect of the invention, cerium is not carried on the remaining catalyst carrier region downstream of the exhaust gas inflow side end region. In the third invention, a three-way catalyst having an enhanced redox capacity by containing cerium is arranged downstream of the catalyst described in the first invention. In the fourth aspect, the amount of palladium carried on the catalyst carrier in the end region of the exhaust gas inflow side is set to 1.0 g or more per liter of exhaust amount of one cylinder in order to ensure a good oxidation reaction.
【００１７】[0017]
【実施例】図１を参照すると、１は機関本体、２は吸気
マニホルド枝管、３は各吸気マニホルド枝管２に取付け
られた燃料噴射弁、４は排気マニホルド、５は排気マニ
ホルド４の集合部内に配置された空燃比センサ、６は短
かい排気管７を介して排気マニホルド４の出口部に接続
されかつ上流側触媒８を内蔵している上流側触媒コンバ
ータ、９は排気管１０を介して上流側触媒コンバータ６
の出口部に接続されかつ下流側触媒１１を内蔵している
下流側触媒コンバータを夫々示す。上流側触媒コンバー
タ６は上流側触媒８内に高温の排気ガスが流入するよう
に排気マニホルド４の出口部の近傍に配置されており、
これに対して下流側触媒コンバータ９は温度低下した排
気ガスが下流側触媒１１内に流入するように車両ボティ
の床下に取付けられている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, 1 is an engine body, 2 is an intake manifold branch pipe, 3 is a fuel injection valve attached to each intake manifold branch pipe, 4 is an exhaust manifold, and 5 is an assembly of an exhaust manifold 4. An air-fuel ratio sensor arranged in the section, 6 is an upstream catalytic converter which is connected to the outlet of the exhaust manifold 4 via a short exhaust pipe 7 and has an upstream catalyst 8 built in, and 9 is an exhaust pipe 10. Upstream catalytic converter 6
2 shows downstream catalytic converters each of which is connected to the outlet of the internal combustion engine and has the downstream catalyst 11 built therein. The upstream catalytic converter 6 is arranged near the outlet of the exhaust manifold 4 so that the high temperature exhaust gas flows into the upstream catalyst 8.
On the other hand, the downstream side catalytic converter 9 is mounted under the floor of the vehicle body so that the exhaust gas having a lowered temperature flows into the downstream side catalyst 11.
【００１８】空燃比センサ５は空燃比がリーンであるか
リッチであるかを示す出力信号を発生し、この出力信号
は制御装置１２に入力される。制御装置１２はこの出力
信号に基いて燃料噴射弁３からの燃料噴射量を制御し、
空燃比がリーンであることを示す出力信号を空燃比セン
サ５が発生しているときには燃料噴射量が徐々に増大せ
しめられ、空燃比がリッチであることを示す出力信号を
空燃比センサ５が発生しているときには燃料噴射量が徐
々に減少せしめられる。その結果、空燃比は理論空燃比
を境にしてリーンとリッチとを交互に繰返し、斯くして
空燃比はほぼ理論空燃比に維持されることになる。The air-fuel ratio sensor 5 generates an output signal indicating whether the air-fuel ratio is lean or rich, and this output signal is input to the control device 12. The control device 12 controls the fuel injection amount from the fuel injection valve 3 based on this output signal,
When the air-fuel ratio sensor 5 is generating an output signal indicating that the air-fuel ratio is lean, the fuel injection amount is gradually increased, and the air-fuel ratio sensor 5 generates an output signal indicating that the air-fuel ratio is rich. The fuel injection amount is gradually decreased while the engine is running. As a result, the air-fuel ratio alternates between lean and rich with the stoichiometric air-fuel ratio as a boundary, and thus the air-fuel ratio is maintained at approximately the stoichiometric air-fuel ratio.
【００１９】図１に示される実施例では上流側触媒８お
よび下流側触媒１１は共にモノリス触媒から形成されて
おり、また上流側触媒８は下流側触媒１１よりも小さな
容積を有する。上流側触媒８は夫々担持されている触媒
の異なる排気ガス流入側端部領域８ａと、排気ガス流入
側端部領域８ａ下流側の残りの触媒領域８ｂとに分けら
れており、排気ガス流入側端部領域８ａの触媒担体には
酸化触媒が担持されており、残りの触媒領域８ｂの触媒
担体には酸化還元触媒、即ち三元触媒が担持されてい
る。In the embodiment shown in FIG. 1, both the upstream side catalyst 8 and the downstream side catalyst 11 are formed of a monolith catalyst, and the upstream side catalyst 8 has a smaller volume than the downstream side catalyst 11. The upstream side catalyst 8 is divided into an exhaust gas inflow side end region 8a and a remaining catalyst region 8b on the downstream side of the exhaust gas inflow side end region 8a, each of which has a different supported catalyst. The catalyst carrier in the end region 8a carries an oxidation catalyst, and the catalyst carrier in the remaining catalyst region 8b carries a redox catalyst, that is, a three-way catalyst.
【００２０】図１に示される実施例では排気ガス流入側
端部領域８ａの触媒担体には半径方向および軸線方向に
一様に分散されたパラジウムＰｄが担持されており、残
りの触媒領域８ｂの触媒担体には白金Ｐｔおよびロジウ
ムＲｈが半径方向および軸線方向に一様に分散されて担
持されている。また、排気ガス流入側端部領域８ａの触
媒担体には白金ＰｔおよびロジウムＲｈは全く担持され
ておらず、残りの触媒領域８ｂの触媒担体にはパラジウ
ムＰｄが全く担持されていない。また、図１に示される
実施例では排気ガス流入側端部領域８ａの触媒担体およ
び残りの触媒担体８ｂにはセリウムＣｅが全く担持され
ていない。なお、図１に示される実施例では残りの触媒
領域８ｂのみの触媒担体にセリウムＣｅを担持させるこ
ともできるが上流側触媒８の製造の容易さという観点か
らみると上流側触媒８の全触媒担体に全くセリウムＣｅ
を担持させないことが好ましい。In the embodiment shown in FIG. 1, the catalyst carrier in the exhaust gas inflow side end region 8a carries palladium Pd which is uniformly dispersed in the radial direction and the axial direction, and the remaining catalyst region 8b is supported. On the catalyst carrier, platinum Pt and rhodium Rh are uniformly dispersed and supported in the radial direction and the axial direction. Further, no platinum Pt or rhodium Rh is supported on the catalyst carrier in the exhaust gas inflow side end region 8a, and no palladium Pd is supported on the catalyst carrier in the remaining catalyst region 8b. Further, in the embodiment shown in FIG. 1, the catalyst carrier in the exhaust gas inflow side end region 8a and the remaining catalyst carrier 8b are not loaded with cerium Ce at all. In addition, in the embodiment shown in FIG. 1, cerium Ce can be supported on the catalyst carrier of only the remaining catalyst region 8b, but from the viewpoint of ease of manufacturing the upstream side catalyst 8, all catalysts of the upstream side catalyst 8 are Cerium Ce as a carrier
Is preferably not supported.
【００２１】一方、下流側触媒１１は三元触媒からな
る。この下流側触媒１１の触媒担体には酸化還元触媒で
あって特にＮＯｘに対して強い還元力を有する白金Ｐｔ
およびロジウムＲｈが担持されており、更にこの下流側
触媒１１には酸化還元能力を高めるためにセリウムＣｅ
が担持されている。機関運転中は空燃比センサ５の出力
信号に基いて空燃比はリーン側とリッチ側に交互に振れ
ながらほぼ理論空燃比に維持されている。このとき排気
ガス中に含まれる未燃ＨＣの大部分およびＣＯの一部が
上流側触媒８の排気ガス流入側端部領域８ａの触媒担体
に担持されたパラジウムＰｄによって酸化せしめられ
る。前述したようにこの排気ガス流入側端部領域８ａの
触媒担体にはセリウムＣｅが担持されていないので排気
ガス流入側端部領域８ａを流れる排気ガス中の酸素は周
期的に過剰となる。その結果、パラジウムＰｄは周期的
に安定した酸化パラジウムＰｄＯとなるので、即ちパラ
ジウムＰｄが金属単体の状態で継続して長時間に亘り存
在することがないのでパラジウムＰｄの金属単体が粒成
長することがなく、斯くしてパラジウムＰｄが劣化し難
くなる。On the other hand, the downstream catalyst 11 is a three-way catalyst. Platinum Pt, which is a redox catalyst and has a strong reducing power especially for NOx, is used as a catalyst carrier of the downstream side catalyst 11.
And rhodium Rh are supported, and cerium Ce is added to the downstream side catalyst 11 in order to enhance the redox capacity.
Is carried. While the engine is operating, the air-fuel ratio is maintained substantially at the stoichiometric air-fuel ratio while alternately swinging to the lean side and the rich side based on the output signal of the air-fuel ratio sensor 5. At this time, most of unburned HC and part of CO contained in the exhaust gas are oxidized by the palladium Pd carried on the catalyst carrier in the exhaust gas inflow side end region 8a of the upstream catalyst 8. As described above, since the catalyst carrier in the exhaust gas inflow side end region 8a does not carry cerium Ce, the oxygen in the exhaust gas flowing in the exhaust gas inflow side end region 8a becomes periodically excessive. As a result, palladium Pd becomes periodically stable palladium oxide PdO, that is, since palladium Pd does not continuously exist in the state of the metal simple substance for a long time, the metal simple substance of palladium Pd grows grains. Therefore, the palladium Pd is less likely to deteriorate.
【００２２】また、前述したように排気ガス流入側端部
領域８ａの触媒担体には白金ＰｔおよびロジウムＲｈが
担持されていない。従ってこの排気ガス流入側端部領域
８ａ内において白金Ｐｔの劣化問題は生じない。排気ガ
ス流入側端部領域８ａを通過した排気ガスは残りの触媒
領域８ｂ内に流入し、この残りの触媒領域８ｂにおいて
ＣＯの酸化作用とＮＯｘの還元作用が行われる。この残
りの触媒領域８ｂ内に流入する排気ガスの温度はかなり
高く、従ってこのとき排気ガス中に多量の酸素が存在す
ると白金Ｐｔが酸化白金ＰｔＯ2となって粒成長してし
まう。しかしながら排気ガス中の酸素は排気ガス流入側
端部領域８ａにおけるパラジウムＰｄによる酸化反応に
より使用されるので残りの触媒領域８ｂ内に流入する排
気ガス中の酸素量は少なく、従って白金Ｐｔが酸化白金
ＰｔＯ2 となって粒成長することがない。斯くして白金
Ｐｔが劣化し難くなる。Further, as described above, platinum Pt and rhodium Rh are not supported on the catalyst carrier in the exhaust gas inflow side end region 8a. Therefore, there is no problem of deterioration of platinum Pt in the exhaust gas inflow side end region 8a. The exhaust gas that has passed through the exhaust gas inflow side end region 8a flows into the remaining catalyst region 8b, and the oxidizing action of CO and the reducing action of NOx are performed in the remaining catalyst region 8b. The temperature of the exhaust gas flowing into the remaining catalyst region 8b is considerably high. Therefore, if a large amount of oxygen is present in the exhaust gas at this time, platinum Pt becomes platinum oxide PtO 2 and grain growth occurs. However, since the oxygen in the exhaust gas is used by the oxidation reaction of the palladium Pd in the exhaust gas inflow side end region 8a, the amount of oxygen in the exhaust gas flowing into the remaining catalyst region 8b is small, so that platinum Pt is platinum oxide. It does not grow into PtO 2 and grow grains. Thus, platinum Pt is less likely to deteriorate.
【００２３】次いで排気ガスは下流側触媒１１内に流入
し、この下流側触媒１１においてＣＯが酸化され、ＮＯ
ｘが還元される。なお、排気ガスが下流側触媒１１内に
流入する頃には排気ガスの温度は低下しており、また下
流側触媒１１に流入する排気ガス中の酸素量は少なくな
っている。従ってこの下流側触媒１１の触媒担体に担持
されている白金Ｐｔは酸化白金ＰｔＯ2 となって粒成長
することがなくなる。Next, the exhaust gas flows into the downstream side catalyst 11, CO is oxidized in the downstream side catalyst 11 and NO
x is reduced. By the time the exhaust gas flows into the downstream side catalyst 11, the temperature of the exhaust gas is lowered and the amount of oxygen in the exhaust gas flowing into the downstream side catalyst 11 is small. Therefore, the platinum Pt supported on the catalyst carrier of the downstream side catalyst 11 becomes platinum oxide PtO 2 and grain growth does not occur.
【００２４】一方、上流側触媒８は排気マニホルド４の
出口部近くに配置されているので上流側触媒８には機関
始動直後から高温の排気ガスが流入し、従って上流側触
媒８は機関始動後すみやかに活性化する。上流側触媒８
が活性化すると排気ガス流入側端部領域８ａ内において
酸化反応が開始され、この酸化反応の反応熱によって残
りの触媒領域８ｂの触媒および下流側触媒１１がすみや
かに活性化される。On the other hand, since the upstream side catalyst 8 is arranged near the outlet of the exhaust manifold 4, high temperature exhaust gas flows into the upstream side catalyst 8 immediately after the engine is started, so that the upstream side catalyst 8 is after the engine is started. Activate quickly. Upstream catalyst 8
Is activated, an oxidation reaction is started in the exhaust gas inflow side end region 8a, and the catalyst in the remaining catalyst region 8b and the downstream side catalyst 11 are promptly activated by the reaction heat of this oxidation reaction.
【００２５】図２は上流側触媒８の排気ガス流入側端部
領域８ａの触媒担体に担持されたパラジウムＰｄによる
未燃ＨＣの浄化率が５０パーセントに達したときの上流
側触媒８の温度ＴとパラジウムＰｄの担持量Ｑとの関係
を示している。なお、パラジウムＰｄの担持量Ｑは１気
筒の排気量１リットル当りのグラム（ｇ／Ｌ）で表わさ
れている。図２に示される上流側触媒８の温度Ｔが低い
ほど機関開始後すみやかに未燃ＨＣを浄化できることに
なり、従って図２に示される上流側触媒８の温度は低い
ほど好ましいことになる。本発明による実施例ではパラ
ジウムＰｄの担持量が１気筒の排気量１リットル当り
１．０グラム以上とされている。FIG. 2 shows the temperature T of the upstream catalyst 8 when the purification rate of unburned HC by the palladium Pd carried on the catalyst carrier in the exhaust gas inflow side end region 8a of the upstream catalyst 8 reaches 50%. Shows the relationship between the amount of palladium Pd supported and Q. The amount P of palladium Pd carried is expressed in grams (g / L) per liter of displacement of one cylinder. As the temperature T of the upstream catalyst 8 shown in FIG. 2 is lower, the unburned HC can be purified more quickly after the engine is started. Therefore, the lower the temperature of the upstream catalyst 8 shown in FIG. 2, the more preferable it is. In the embodiment according to the present invention, the amount of palladium Pd carried is set to 1.0 g or more per liter of displacement of one cylinder.
【００２６】また、図１に示される実施例では上流側触
媒８の触媒担体に担持されている白金Ｐｔの量は触媒１
リットル当り約１．５グラムであり、上流側触媒８の触
媒担体に担持されているロジウムＲｈの量は触媒１リッ
トル当り約０．３グラムとされている。また、下流側触
媒１１の触媒担体に担持されている白金Ｐｔおよびロジ
ウムＲｈの量は夫々触媒１リットル当り約１．０グラム
および０．２グラムであり、下流側触媒１１の触媒担体
に担持されているセリウムＣｅの量は触媒１リットル当
り０．３から０．４５mol とされている。In the embodiment shown in FIG. 1, the amount of platinum Pt supported on the catalyst carrier of the upstream side catalyst 8 is the same as that of the catalyst 1
It is about 1.5 grams per liter, and the amount of rhodium Rh supported on the catalyst carrier of the upstream side catalyst 8 is about 0.3 grams per liter of the catalyst. Further, the amounts of platinum Pt and rhodium Rh supported on the catalyst carrier of the downstream side catalyst 11 are about 1.0 gram and 0.2 gram per liter of the catalyst, respectively, which are supported on the catalyst carrier of the downstream side catalyst 11. The amount of cerium Ce contained is 0.3 to 0.45 mol per liter of catalyst.
【００２７】図３は本発明をＶ型エンジンに適用した場
合を示す。なお、図３において図１と同様な構成要素は
同一の符号で示す。図３に示される実施例では機関本体
の各バンク１２，１３に対して夫々排気マニホルド４が
取付けられ、各排気マニホルド４は排気管７を介して夫
々別個の上流側触媒コンバータ６に連結される。各上流
側コンバータ６内には夫々図１に示す上流側触媒８と同
様な上流側触媒８が配置されている。各上流側触媒コン
バータ６は対応する排気管１０′を介して共通の排気管
１０に接続され、この排気管１０は下流側触媒コンバー
タ９に接続される。下流側触媒コンバータ９内には図１
に示す下流側触媒１１と同様な下流側触媒１１が配置さ
れている。FIG. 3 shows a case where the present invention is applied to a V-type engine. In FIG. 3, the same components as those in FIG. 1 are designated by the same reference numerals. In the embodiment shown in FIG. 3, an exhaust manifold 4 is attached to each bank 12 and 13 of the engine body, and each exhaust manifold 4 is connected to a separate upstream side catalytic converter 6 via an exhaust pipe 7. . An upstream catalyst 8 similar to the upstream catalyst 8 shown in FIG. 1 is arranged in each upstream converter 6. Each upstream catalytic converter 6 is connected to a common exhaust pipe 10 via a corresponding exhaust pipe 10 ′, and this exhaust pipe 10 is connected to a downstream catalytic converter 9. In the downstream catalytic converter 9, FIG.
A downstream side catalyst 11 similar to the downstream side catalyst 11 shown in FIG.
【００２８】[0028]
【発明の効果】触媒担体に担持されたパラジウムや白金
が劣化するのを阻止しつつ排気ガス中の未燃ＨＣ，ＣＯ
およびＮＯｘを良好に浄化することができる。EFFECTS OF THE INVENTION Unburned HC and CO in exhaust gas are prevented while preventing deterioration of palladium and platinum supported on a catalyst carrier.
And NOx can be satisfactorily purified.
【図１】内燃機関の全体図である。FIG. 1 is an overall view of an internal combustion engine.
【図２】未燃ＨＣの浄化率が５０パーセントに達したと
きの触媒の温度Ｔとパラジウムの担持量Ｑとの関係を示
す図である。FIG. 2 is a diagram showing a relationship between a catalyst temperature T and a palladium loading amount Q when the purification rate of unburned HC reaches 50%.
【図３】内燃機関の別の実施例を示す全体図である。FIG. 3 is an overall view showing another embodiment of an internal combustion engine.
４…排気マニホルド ８…上流側触媒 ８ａ…排気ガス流入側端部領域 １１…下流側触媒 4 ... Exhaust manifold 8 ... Upstream catalyst 8a ... Exhaust gas inflow end region 11 ... Downstream catalyst
Claims (4)
を配置し、排気通路内に設けた空燃比センサの出力信号
に基いて空燃比をほぼ理論空燃比に維持するようにした
内燃機関において、該触媒担体の排気ガス流入側端部領
域のみにパラジウムを担持させると共に該排気ガス流入
側端部領域下流側の残りの触媒担体領域のみに白金およ
びロジウムを担持させ、上記排気ガス流入側端部領域の
触媒担体上にはセリウムを担持させないようにした内燃
機関の排気ガス浄化装置。1. An internal combustion engine in which an exhaust gas purifying catalyst is arranged in an exhaust passage of an engine, and an air-fuel ratio is maintained substantially at a stoichiometric air-fuel ratio based on an output signal of an air-fuel ratio sensor provided in the exhaust passage. In the above method, palladium is supported only on the exhaust gas inflow side end region of the catalyst carrier, and platinum and rhodium are supported only on the remaining catalyst carrier region on the downstream side of the exhaust gas inflow side end region. An exhaust gas purifying device for an internal combustion engine in which cerium is not supported on the catalyst carrier in the end region.
セリウムを担持させないようにした請求項１に記載の内
燃機関の排気ガス浄化装置。2. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein no cerium is supported on the entire catalyst carrier.
含んだ三元触媒を配置した請求項１に記載の内燃機関の
排気ガス浄化装置。3. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein a three-way catalyst containing cerium is arranged in the exhaust passage downstream of the catalyst.
に担持されたパラジウムの量を１気筒の排気量１リット
ル当り１．０グラム以上とした請求項１に記載の内燃機
関の排気ガス浄化装置。4. The exhaust gas of an internal combustion engine according to claim 1, wherein the amount of palladium carried on the catalyst carrier in the exhaust gas inflow side end region is 1.0 g or more per 1 liter of displacement of one cylinder. Purification device.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6142953A JPH0814029A (en) | 1994-06-24 | 1994-06-24 | Exhaust emission control device for internal combustion engine |
| GB9512610A GB2290488A (en) | 1994-06-24 | 1995-06-21 | Exhaust emission control device for internal combustion engines |
| DE19522913A DE19522913A1 (en) | 1994-06-24 | 1995-06-23 | Exhaust emission control device for an internal combustion engine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6142953A JPH0814029A (en) | 1994-06-24 | 1994-06-24 | Exhaust emission control device for internal combustion engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0814029A true JPH0814029A (en) | 1996-01-16 |
Family
ID=15327499
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6142953A Pending JPH0814029A (en) | 1994-06-24 | 1994-06-24 | Exhaust emission control device for internal combustion engine |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH0814029A (en) |
| DE (1) | DE19522913A1 (en) |
| GB (1) | GB2290488A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6672051B2 (en) | 2000-03-30 | 2004-01-06 | Mitsubishi Jidosha Kogyo Kabushiki Kaisha | Exhaust emission purifying device for internal combustion engine |
| WO2004025096A1 (en) * | 2002-09-13 | 2004-03-25 | Johnson Matthey Public Limited Company | Process for treating compression ignition engine exhaust gas |
| KR100506780B1 (en) * | 2002-06-20 | 2005-08-05 | 현대자동차주식회사 | Three way catalyst for automobile and method for manufacturing it |
| US7700050B2 (en) | 2003-09-30 | 2010-04-20 | Emitec Gesellschaft Fuer Emissionstechnologie Mbh | Coated honeycomb body assembly with measurement sensor and exhaust system having the assembly |
| JP2011106999A (en) * | 2009-11-18 | 2011-06-02 | Horiba Ltd | Dilution air refining method and dilution air refining device |
| JP2014089216A (en) * | 2014-02-17 | 2014-05-15 | Sumitomo Metal Mining Engineering Co Ltd | Dilution air refining method, dilution air refining device, constant capacity sampling device, and exhaust gas sampling analysis system |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5846502A (en) * | 1996-01-16 | 1998-12-08 | Ford Global Technologies, Inc. | Mini-cascade catalyst system |
| DE19640161A1 (en) * | 1996-09-28 | 1998-04-02 | Volkswagen Ag | NOx emission control process |
| DE50005206D1 (en) * | 2000-08-16 | 2004-03-11 | Umicore Ag & Co Kg | Exhaust gas purification catalytic converter for use near the engine and process for its production |
| US7276212B2 (en) * | 2001-10-01 | 2007-10-02 | Engelhard Corporation | Exhaust articles for internal combustion engines |
| DE10218232A1 (en) * | 2002-04-24 | 2003-11-06 | Opel Adam Ag | Process for improving effectiveness of diesel fuel injected into exhaust gas pipe of an I.C. engine in front of an SCR catalyst comprises converting diesel fuel by partial cracking into an active form before conversion of nitrogen oxides |
| DE102004036478B4 (en) | 2003-07-30 | 2007-07-19 | Mitsubishi Jidosha Kogyo K.K. | Exhaust emission removing catalyst device |
| DE102005003221A1 (en) * | 2005-01-24 | 2006-07-27 | Volkswagen Ag | Catalyst device for vehicle diesel combustion engine, has carrier structure with zones comprising metal, and ceramics, respectively, where catalytic action provided in area of former zone is lowered in comparison to latter zone |
| GB0603942D0 (en) | 2006-02-28 | 2006-04-05 | Johnson Matthey Plc | Exhaust system for a spark-ignited internal combustion engine |
| EP1832332B1 (en) * | 2006-03-09 | 2016-05-04 | Haldor Topsøe A/S | Process and system for purification of sulphur-containing exhaust gas |
| GB0716833D0 (en) | 2007-08-31 | 2007-10-10 | Nunn Andrew D | On board diagnostic system |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4448756A (en) * | 1983-01-28 | 1984-05-15 | Ford Motor Company | Process for treatment of exhaust gases |
| JPS63136245A (en) * | 1986-11-28 | 1988-06-08 | Nec Corp | Control system for application of system resources |
| DE3823550A1 (en) * | 1988-07-12 | 1990-01-18 | Bayerische Motoren Werke Ag | Vehicle exhaust system with a catalytic converter body |
| AU6853490A (en) * | 1989-12-27 | 1991-07-04 | Nippon Shokubai Kagaku Kogyo Co. Ltd. | Method for purification of exhaust gas and apparatus therefor |
| JPH04118053A (en) * | 1989-12-29 | 1992-04-20 | Tokyo Roki Kk | Catalyst for cleaning exhaust gas from engine |
| US5106588A (en) * | 1990-07-30 | 1992-04-21 | General Motors Corporation | Monolithic catalytic converter |
| JPH04287820A (en) * | 1991-03-18 | 1992-10-13 | Nissan Motor Co Ltd | Exhaust gas purifying device for internal combustion engine |
| DE4236893A1 (en) * | 1991-11-16 | 1993-05-19 | Volkswagen Ag | Exhaust gas system for internal combustion engines - has exhaust pipes leading from cylinder head exhaust duct and catalytic converter arrangement |
| JPH06268543A (en) * | 1993-03-12 | 1994-09-22 | Clarion Co Ltd | Rds receiver |
-
1994
- 1994-06-24 JP JP6142953A patent/JPH0814029A/en active Pending
-
1995
- 1995-06-21 GB GB9512610A patent/GB2290488A/en not_active Withdrawn
- 1995-06-23 DE DE19522913A patent/DE19522913A1/en not_active Ceased
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6672051B2 (en) | 2000-03-30 | 2004-01-06 | Mitsubishi Jidosha Kogyo Kabushiki Kaisha | Exhaust emission purifying device for internal combustion engine |
| DE10115431B4 (en) * | 2000-03-30 | 2005-04-21 | Mitsubishi Jidosha Kogyo K.K. | Emission control device for gasoline engine |
| KR100506780B1 (en) * | 2002-06-20 | 2005-08-05 | 현대자동차주식회사 | Three way catalyst for automobile and method for manufacturing it |
| WO2004025096A1 (en) * | 2002-09-13 | 2004-03-25 | Johnson Matthey Public Limited Company | Process for treating compression ignition engine exhaust gas |
| US7485270B2 (en) | 2002-09-13 | 2009-02-03 | Johnson Matthey Public Limited Company | Process for treating compression ignition engine exhaust gas |
| US8006485B2 (en) | 2002-09-13 | 2011-08-30 | Johnson Matthey Public Limited Company | Compression ignition engine and exhaust system therefor |
| US7700050B2 (en) | 2003-09-30 | 2010-04-20 | Emitec Gesellschaft Fuer Emissionstechnologie Mbh | Coated honeycomb body assembly with measurement sensor and exhaust system having the assembly |
| JP2011106999A (en) * | 2009-11-18 | 2011-06-02 | Horiba Ltd | Dilution air refining method and dilution air refining device |
| JP2014089216A (en) * | 2014-02-17 | 2014-05-15 | Sumitomo Metal Mining Engineering Co Ltd | Dilution air refining method, dilution air refining device, constant capacity sampling device, and exhaust gas sampling analysis system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2290488A (en) | 1996-01-03 |
| GB9512610D0 (en) | 1995-08-23 |
| DE19522913A1 (en) | 1996-01-04 |
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