Exhaust gas purifying device for internal combustion engine

• US 20030154713A1
• Filed: 01/16/2003
• Published: 08/21/2003
• Est. Priority Date: 01/16/2002
• Status: Abandoned Application

• Current Assignee: Hitachi Car Engineering Company Limited (Hitachi, Ltd.), Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kuroda, Osamu, Inoue, Takeshi, Okude, Mariko, Shinotsuka, Norihiro, Kitahara, Yuichi, Hiratsuka, Toshifumi, Okude, Kojiro, Doi, Ryouta
• Application Number:
  US10/345,415
• Publication Number:
  US 20030154713A1
• Time in Patent Office: Days
• US Class Current: 60/297
• CPC Class Codes: B01D 2255/1021 Platinum
• CPC Class Codes: B01D 2255/1023 Palladium
• CPC Class Codes: B01D 2255/1025 Rhodium
• CPC Class Codes: B01D 2255/2022 Potassium
• CPC Class Codes: B01D 2255/2027 Sodium
• CPC Class Codes: B01D 2255/2042 Barium
• CPC Class Codes: B01D 2255/207 Transition metals
• CPC Class Codes: B01D 53/9422 for removing nitrogen oxides by NOx storage or reduction by cyclic switching between lean and rich exhaust gases (LNT, NSC, NSR)
• CPC Class Codes: B01D 53/9431 Processes characterised by a specific device
• CPC Class Codes: B01D 53/944 Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts three-way-catalysts [TWC] B01D53/9445
• CPC Class Codes: B01D 53/9445 Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
• CPC Class Codes: B01D 53/9477 with catalysts positioned on separate bricks, e.g. exhaust systems
• CPC Class Codes: F01N 13/009 having two or more separate purifying devices arranged in series
• CPC Class Codes: F01N 3/035 with catalytic reactors , e.g. catalysed diesel particulate filters
• CPC Class Codes: F01N 3/0814 combined with catalytic converters, e.g. NOx absorption/storage reduction catalysts
• CPC Class Codes: F01N 3/0842 Nitrogen oxides
• CPC Class Codes: F01N 3/281 Metallic honeycomb monoliths made of stacked or rolled sheets, foils or plates
• CPC Class Codes: F01N 3/2828 Ceramic multi-channel monoliths, e.g. honeycombs
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

An exhaust gas purifying device which can sufficiently perform HC purification even if a lean NOx catalyst included in a metal substrate is used. The exhaust gas purifying device comprises, in an exhaust passage in an internal combustion engine along a flowing direction of the exhaust gas, a lean NOx catalyst including a catalyst layer which purifies nitrogen oxide contained in the exhaust gas under a hyperoxia atmosphere and a metal honeycomb, the lean NOx catalyst having the catalyst layer supported within the metal honeycomb; and a reaction catalyst for subjecting to an oxidation reaction at least hydrocarbon contained in the exhaust gas.

Claims

1. An exhaust gas purifying device for an internal combustion engine used for purifying exhaust gas exhausted from the internal combustion engine through an exhaust passage, comprising:

a lean NOx catalyst including a catalyst layer which purifies nitrogen oxide contained in the exhaust gas under a hyperoxia atmosphere and a metal honeycomb, said lean NOx catalyst having the catalyst layer supported within the metal honeycomb; and

a reaction catalyst for subjecting to an oxidation reaction at least hydrocarbon contained in the exhaust gas;

said lean NOx catalyst and said reaction catalyst being disposed in the exhaust passage along a flowing direction of the exhaust gas.

2. An exhaust gas purifying device for an internal combustion engine used for purifying exhaust gas exhausted from the internal combustion engine through an exhaust passage, comprising:

a lean NOx catalyst including a catalyst layer which purifies nitrogen oxide contained in the exhaust gas under a hyperoxia atmosphere and a metal honeycomb, said lean NOx catalyst having the catalyst layer supported within the metal honeycomb; and

a reaction catalyst for subjecting to an oxidation reaction hydrocarbon and carbon monoxide contained in the exhaust gas downstream of said lean NOx catalyst;

said lean NOx catalyst and said reaction catalyst being disposed in the exhaust passage.

3. An exhaust gas purifying device for an internal combustion engine used for purifying exhaust gas exhausted from the internal combustion engine through an exhaust passage, comprising:

a lean NOx catalyst including a catalyst layer which traps nitrogen oxide contained in the exhaust gas with a trapping material so that the trapped nitrogen oxide is purified by reduction and a metal honeycomb, said lean NOx catalyst having the catalyst layer supported within the metal honeycomb; and

a reaction catalyst including a catalyst layer for subjecting to an oxidation reaction at least hydrocarbon contained in the exhaust gas and a cordierite substrate, said reaction catalyst having the catalyst layer supported within the cordierite substrate;

said lean NOx catalyst and said reaction catalyst being disposed in the exhaust passage along a flowing direction of the exhaust gas.

4. An exhaust gas purifying device for an internal combustion engine used for purifying exhaust gas exhausted from the internal combustion engine through an exhaust passage, comprising:

a lean NOx catalyst including a catalyst layer which purifies nitrogen oxide contained in the exhaust gas under a hyperoxia atmosphere and a metal honeycomb, said lean NOx catalyst having the catalyst layer supported within the metal honeycomb; and

a three-way catalyst for purifying nitrogen oxide, hydrocarbon, and carbon monoxide contained in the exhaust gas;

said lean NOx catalyst and said three-way catalyst being disposed in the exhaust passage along a flowing direction of the exhaust gas.

5. An exhaust gas purifying device for an internal combustion engine used for purifying exhaust gas exhausted from the internal combustion engine through an exhaust passage, comprising:

a three-way catalyst;

a lean NOx catalyst including a catalyst layer which purifies nitrogen oxide contained in the exhaust gas under a hyperoxia atmosphere and a metal honeycomb, said lean NOx catalyst having the catalyst layer supported within the metal honeycomb; and

a reaction catalyst for subjecting to an oxidation reaction at least hydrocarbon contained in the exhaust gas;

said three-way catalyst, said lean NOx catalyst, and said reaction catalyst being disposed in the exhaust passage along a flowing direction of the exhaust gas.

6. An exhaust gas purifying device for an internal combustion engine used for purifying exhaust gas exhausted from the internal combustion engine through an exhaust passage, comprising:

a filter for eliminating carbon particles contained in the exhaust gas;

a lean NOx catalyst including a catalyst layer which purifies nitrogen oxide contained in the exhaust gas under a hyperoxia atmosphere and a metal substrate, said lean NOx catalyst having the catalyst layer supported within the metal substrate; and

a reaction catalyst for subjecting to an oxidation reaction at least hydrocarbon contained in the exhaust gas;

said filter, said lean NOx catalyst, and said reaction catalyst being disposed in the exhaust passage along a flowing direction of the exhaust gas.

7. An exhaust gas purifying device for an internal combustion engine used for purifying exhaust gas exhausted from the internal combustion engine through an exhaust passage, comprising:

a lean NOx catalyst including a catalyst layer which purifies nitrogen oxide contained in the exhaust gas under a hyperoxia atmosphere and a metal honeycomb, said lean NOx catalyst having the catalyst layer supported within the metal honeycomb to eliminate carbon particles contained in the exhaust gas; and

a reaction catalyst for subjecting to an oxidation reaction at least hydrocarbon contained in the exhaust gas;

said lean NOx catalyst and said reaction catalyst being disposed in the exhaust passage along a flowing direction of the exhaust gas.