Hitachi, Ltd.

Other

Honda Motor Co., Ltd.

Yuichi Kitahara

Osamu Kuroda

Hidehiro Iizuka

Hisao Yamashita

Toshio Ogawa

Toshifumi Hiratsuka

Norihiro Shinotsuka

Ryouta Doi

Shigeru Azuhata

Kojiro Okude

Hiroshi Hanaoka

Takeshi Atago

Masato Kaneeda

Toshio Manaka

Hiroatsu Tokuda

Kousei Nagayama

Akira Kato

Seiji Suda

Hiroshi Miyadera

Yoshiya Takano

Morio Fujitani

Toshio Hori

Takeshi Inoue

Takao Ishikawa

Masayuki Kamikawa

Hiroshi Tobita

Shinichi Ichikawa

Hidehiro Ilzuka

Hiroko Watanabe

Hid&eacute;hiro Iizuka

Toshikatsu Takanohashi

Hiroshi Oono

Mariko Okude, Legal Representative

Hiroshi Kodairajousui Hausu 205 Hanaoka

A catalyst for use in purifying exhaust gas from an internal combustion engine. The active components of an exhaust gas purification catalyst for an internal combustion engine tend to be melted or softened and then to move outside the carrier, because the components become in contact with exhaust gas at a high temperature. Hence, anchoring materials are provided between carriers in order to suppress the moving of catalytically active components. Anchoring materialsdo not form compounds with catalytically active components, and are selected from substances that do not melt even in contact with exhaust gas at a high temperature. When the active components contain sodium, potassium, cesium, lithium, strontium, barium, noble metals and the like, the best anchoring material is MgO. The anchoring material functions as a barrier that prevents the moving of active components.

Emission gas purification catalyst and internal combustion engine provided with the catalyst

An exhaust gas purification apparatus for use in an internal combustion engine comprises an exhaust gas duct connected to the engine through which the exhaust gas containing NOx gas passes and a catalyst so disposed in the exhaust gas duct that it contacts with the exhaust gas. The catalyst chemically adsorbs NOx under the condition that a stoichiometric amount of a gaseous oxidizing agent present in the exhaust gas is larger than that of a gaseous reducing agent present in the exhaust gas for reducing NOx, while NOx being adsorbed is catalytically reduced in the presence of the reducing agent under the condition that the stoichiometric amount of the oxidizing agent is not larger that of the reducing agent. Thereby, NOx, the lean burn exhaust gas in the engine can be effectively made harmlessly.

Exhaust gas purification apparatus of internal combustion engine and catalyst for purifying exhaust gas of internal combustion engine

An exhaust gas purification apparatus for purifying exhaust gas exhausted from a diesel internal combustion engine and containing therein harmful substances including particulates, NOx, HC and CO, at least, comprises a removal part for trapping and removing particulates in the exhaust gas, a purification part for purifying NOx, HC and CO through contact, and a heat transfer part for transferring heat generated in the removal part to the purification part.

Exhaust gas purification apparatus

In a method and apparatus for removing nitrogen oxides from the exhaust gas of a lean-burn automobile, a CO adsorbent component, which may, for example be made of Pd, Ru or Ir, is contained in an exhaust gas cleaning catalyst which captures NOx when the air-fuel ratio of exhaust gas is higher than theoretical air-fuel ratio, and reduces the captured NOx when the air-fuel ratio of exhaust gad is less than or equal to the theoretical air-fuel ratio. The catalyst, which includes Rh, Pt, and element selected from among the alkaline and alkaline earth metals (Na, Mg, K, Li, Cs, Sr and Ca), and a CO adsorbent material comprising Pd, Ir or Ru, has a CO desorption capacity that reaches at maximum level at a temperature within the range from 200 to 220&#xb0; C. when its temperature is increased in a He gas flow at the rate of 5 to 10&#xb0; C./min, after said catalyst is saturated at 100&#xb0; C. Exhaust gas having an air-fuel ratio higher than theoretical air-fuel and exhaust gas having an air-fuel ratio less than or equal to the theoretical air-fuel ratio are alternately made to flow to the catalyst.

Method for cleaning exhaust gas from an internal combustion engine

Nitrogen oxides contained in an exhaust gas emitted from a lean-burn engine-mounted internal combustion engines are eliminated with a high efficiency. In an exhaust gas purification apparatus and process for eliminating nitrogen oxides contained in a combustion exhaust gas emitted from an internal combustion engine with a reducing gas such as carbon monoxide, hydrocarbons, etc. contained in the exhaust gas in the presence of a catalyst, a catalyst comprising all of Rh, Pt and Pd, at least one member selected from alkali metals and alkaline earth metals, and Mn or its compound, supported on a porous carrier is used.

Internal combustion engine exhaust gas purification apparatus, exhaust gas purification process and exhaust gas purification catalyst

A moisture removal device for an internal combustion engine use exhaust gas purifying device with a trapped moisture amount estimation means which estimates amount of moisture exhausted from an internal combustion engine and trapped in the catalyst, a judgement means which judges whether the estimated value of the trapped moisture amount exceeds a predetermined amount, and means for controlling removal of the moisture trapped in the catalyst, wherein when the estimated value of moisture trapped in the catalyst exceeds the predetermined value, a control of removing the moisture in the catalyst is performed. Whereby, since the moisture trapped by the catalyst can be removed and a possible elution of the catalyst components can be prevented, reduction of exhaust gas purifying performance of the catalyst can be prevented.

Moisture removal device and method thereof for internal combustion engine use exhaust gas cleaning device

In an exhaust gas purification process for eliminating nitrogen oxides contained in a combustion exhaust gas emitted from an internal combustion engine with a reducing gas such as carbon monoxide, hydrocarbons, etc. contained in the exhaust gas in the presence of a catalyst, a catalyst comprising all of Rh, Pt and Pd, at least one member selected from alkali metals and alkaline earth metals, and Mn or its compound, supported on a porous carrier is used.

Exhaust emission control process for internal combustion engines

A catalyst being formed of a porous supporter supporting alkali metals, Ti and noble metal, or further supporting at least one of rare earth metal and magnesium, being disposed in a flow passage of the internal combustion engine, and being used to purify NOx contained in the exaust gas. The above catalyst has excellent NO resistance not only to the exaust gas burnt with the stoichiometric air-to-fuel ratio or rich condition, but to the exhaust gas burnt with the lean condition, and furthermore has a high resistivity to poisoning of SOx slightly contained in the fuel.

Method for purifying exhaust gas from internal combustion engines

Exhaust gas from internal combustion engines is treated with catalyst comprising an inorganic oxide supporter which supports at least one of noble metals selected from Rh, Pt, and Pd, alkali rare earth metals, rare earth metals, and magnesium in order to remove NOx effectively with superior durability of the catalyst notwithstanding the internal combustion engine is under a stoichiometric operation condition or a lean burning operation condition.

Exhaust gas purifying apparatus for an internal combustion engine

An engine control device provided with a lean NOx catalyst comprises means for estimating a condition of the lean NOx catalyst, means for performing reactivation control of the lean NOx catalyst based on the result, and means for controlling the termination of the reactivation control. The lean NOx catalyst is constantly made usable in a favorable condition.

Engine control device

An exhaust gas purification apparatus for use in an internal combustion engine comprises an exhaust gas duct connected to the engine through which the exhaust gas containing NOx gas passes and a catalyst so disposed in the exhaust gas duct that it contacts with the exhaust gas. The catalyst chemically adsorbs NOx under the condition that a stoichiometric amount of a gaseous oxidizing agent present in the exhaust gas is larger than that of a gaseous reducing agent present in the exhaust gas for reducing NOx, while NOx being adsorbed is catalytically reduced in the presence of the reducing agent under the condition that the stoichiometric amount of the oxidizing agent is not larger that of the reducing agent. Thereby, NOx the lean burn exhaust gas in the engine can be effectively made harmlessly.

A method of and apparatus for purifying an exhaust gas of an internal combustion engine comprising an NO,purifying catalyst arranged in an exhaust gas passage, wherein the NO,purifying catalyst is made of a composite material containing at least one kind of element selected from alkaline metals and alkaline earth metals, at least one kind of element selected from rare earth metals, at least one kind of element selected from platinoid metals, and titanium (Ti), the NO,purifying catalyst adsorbing NO,in the exhaust gas onto the surface when the exhaust gas is lean, and reducing the adsorbed NO,to N,when the exhaust gas is stoichiometric or rich, and wherein the exhaust gas is purified by adsorbing NO,in the exhaust gas in the NO,purifying catalyst when the internal combustion engine is being operated under a lean condition, and by setting, after the adsorption, the exhaust gas to a stochiometric state or a rich state for 0.5 second to 4.5 seconds to reduce the NO,adsorbed in said NO,purifying catalyst to N,through catalytic reaction with the reducing agent.

Method of purifying exhaust gas of internal combustion engine and apparatus thereof

An apparatus and method of highly efficiently purifying nitrogen oxides are provided. An NOx chemisorption reduction catalyst chemically absorbs NOx under a condition that an exhaust gas of an internal combustion engine is an oxidizing atmosphere and deoxidizes adsorbed NOx under a reducing atmosphere. An SOx absorbent absorbs SOx contained in the exhaust gas of the oxidizing atmosphere, and deoxidizes and release SOx absorbed in the reducing atmospheric exhaust gas. The catalyst and absorbent are arranged in the exhaust path to purify the exhaust gas while preventing or suppressing SOx-poisoning of the NOx chemisorption reduction catalyst.

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Hitachinaka, Japan

Yuichi Kitahara