Exhaust gas purifying catalyst
AssigneeNissan Motor Co., Ltd.
InventorShinji Yamamoto
Life of this patent
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Abstract
An exhaust gas purifying catalyst for purifying exhaust gas discharged from an automotive internal combustion engine. The exhaust gas purifying catalyst comprises a monolithic substrate. A HC adsorbing layer for adsorbing hydrocarbons (HC) is formed on the monolithic substrate. The HC absorbing layer contains zeolite. A catalytic layer for producing hydrogen (H2) and reducing NOx is formed on the HC adsorbing layer. The catalytic layer functions to produce hydrogen (H2) from at least one of hydrocarbons and carbon monoxide (CO) and to reduce nitrogen oxides (NOx) with the produced hydrogen and at least one of hydrocarbons and carbon monoxide in exhaust gas.
Claims15
An exhaust gas purifying system for an internal combustion engine, comprising:
- an exhaust gas purifying catalyst including
- a monolithic substrate,
- a HC adsorbing layer for adsorbing hydrocarbons (HC), said HC absorbing layer being formed on said monolithic substrate, and
- a catalytic layer for producing hydrogen (H2) and reducing NOx, said catalytic layer functioning to produce hydrogen (H2) from at least one of hydrocarbons and carbon monoxide (CO) and to reduce nitrogen oxides (NOx) with the produced hydrogen and at least one of hydrocarbons and carbon monoxide in exhaust gas, said catalytic layer being formed on said HC adsorbing layer;
- and
- a device for controlling combustion in the engine to produce exhaust gas, to be brought into contact with said catalytic layer, having a composition meeting a relation [(a concentration of hydrogen/a concentration of total reducing components)≧0.3].
A method comprising:
- providing an exhaust gas purifying catalyst, the exhaust gas purifying catalyst comprising:
- a monolithic substrate;
- a HC adsorbing layer for adsorbing hydrocarbons (HC), said HC absorbing layer containing zeolite and being formed on said monolithic substrate;
- and
- a catalytic layer for producing hydrogen (H2) and reducing NOx, said catalytic layer functioning to produce hydrogen (H2) from at least one of hydrocarbons and carbon monoxide (CO) and to reduce nitrogen oxides (NOx) with the produced hydrogen and at least one of hydrocarbons and carbon monoxide in exhaust gas, said catalytic layer being formed on said HC adsorbing layer;
- and
- supplying exhaust gas to contact said catalytic layer, the exhaust gas having a composition meeting a relation [(a concentration of hydrogen/a concentration of total reducing components)≧0.3].
Dependencies are inferred from the claim text.