Abstract: An exhaust gas purification filter for a diesel internal combustion engine. In this filter, catalyst layers are not formed at portions to which a sealant of the filter is stuck so that a substrate of the honeycomb structure is exposed, but formed at portions to which a substrate of the honeycomb structure is exposed. If the sealant is stuck to catalyst layer portions, because the catalyst layers are brittle and the surfaces thereof have asperities, the fixing strength of the sealant is reduced, so that the sealing portions becomes prone to falling-off under shocks or the like. By exposing the substrate of the honeycomb structure and sticking the sealant to the exposed portions, it is possible to enhance the fixing strength of the sealant and thereby to prevent the sealing portions from falling off.

Abstract: In an exhaust gas purifying apparatus provided with a lean NOx catalyst supporting a catalyst layer, which contains a NOx trapping component, on a honeycomb substrate formed so as not to cause an alkali attack, the invention prevents trapped NOx from being dissociated and exhausted during the time of a rich spike. A NOx reducing catalyst with the function of reducing NOx by a reductant in a rich or stoichiometric condition, e.g., a three-way catalyst, is disposed downstream of the lean NOx catalyst. In the case of increasing the amount of the NOx trapping component in the lean NOx catalyst to enhance a NOx trapping capability, even if a part of trapped NOx is dissociated during the time of the rich spike, the dissociated NOx can be reduced by the NOx reducing catalyst disposed on the downstream side.

Abstract: An exhaust gas purification apparatus for use in an internal combustion engine comprises an exhaust gas duct connected to the engine through which exhaust gas containing NOx gas passes, and a catalyst disposed in the exhaust gas duct such that it contacts the exhaust gas. The catalyst chemically adsorbs NOx when 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, adsorbed NOx is catalytically reduced in the presence of a reducing agent when the stoichiometric amount of the oxidizing agent is not larger that of the reducing agent.

Abstract: 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° C. when its temperature is increased in a He gas flow at the rate of 5 to 10° C./min, after said catalyst is saturated at 100° C.

Abstract: 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.

Abstract: 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 materials 22 do not form compounds with catalytically active components 24, 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.

Abstract: Nitrogen oxides contained in an exhaust gas emitted from a lean-burn engine-mounted internal combustion engines are eliminated with a high efficiency.

Abstract: 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.

Abstract: 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 NOx 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.

Abstract: 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.

Abstract: 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 than that of the reducing agent. Thereby, NOx, the lean burn exhaust gas in the engine can be effectively made harmlessly.

Abstract: 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.

Abstract: A method of and apparatus for purifying an exhaust gas of an internal combustion engine comprising an NOx purifying catalyst arranged in an exhaust gas passage, wherein the NOx 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 NOx purifying catalyst adsorbing NOx in the exhaust gas onto the surface when the exhaust gas is lean, and reducing the adsorbed NOx to N2 when the exhaust gas is stoichiometric or rich, and wherein the exhaust gas is purified by adsorbing NOx in the exhaust gas in the NOx 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.

Abstract: 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.

Abstract: An exhaust gas purification apparatus for use in an internal combustion engine comprises an exhaust gas duct connected to the engine through which exhaust gas containing NO.sub.x gas passes, and a catalyst disposed in the exhaust gas duct such that it contacts the exhaust gas. The catalyst chemically adsorbs NO.sub.x when 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 NO.sub.x, adsorbed NO.sub.x is catalytically reduced in the presence of a reducing agent when the stoichiometric amount of the oxidizing agent is not larger that of the reducing agent.

Abstract: 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.

Abstract: An exhaust gas purifying catalyst is provided for purifying NOx contained in an exhaust gas from an internal combustion engine of a vehicle operated at a high air fuel ratio due to excessive oxygen, using unburnt HC or CO in the exhaust gas as a reducing agent. The catalyst comprises platinum, strontium and a rare earth metal, as active components, each supported on a support of inorganic oxide. The active components of the catalyst include platinum of 0.01-3.7 by wt ratio, strontium of 0.01-55 by wt ratio and a rare earth metal of 0.01-36 wt ratio, per the inorganic oxide of 100 by wt ratio.

Abstract: In order to remove nitrogen oxide in an exhaust gas released from a lean burn engine, a catalyst: supporting an rare earth metal, an alkali earth metal, titanium, a noble metal, and magnesium on the surface of a porous carrier made of inorganic oxides is provided. In order to manufacture the catalyst, the rare earth metal is supported onto the surface of the carrier first, subsequently the alkali earth metal other than magnesium and titanium are supported, the noble metal is supported, and magnesium is supported finally onto the surface of the carrier.The catalyst of the present invention is scarcely poisoned by SOx in the exhaust gas released from the lean burn engine, and has a heat resistivity durable against high speed driving.

Abstract: A catalyst being formed of a porous supporter supporting alkali metals, Ti and a noble metal, or further supporting at least one of rare earth metal and magnesium, being disposed in a flow passage of an internal combustion engine, and being used to purify NOx contained in the exhaust gas. The above catalyst has NOx resistance to exhaust gas burnt with a rich condition and with a lean condition and a high resistivity to poisoning by SOx.