| 摘要 |
A catalytic converter for purification of exhaust gas discharged from an automotive internal combustion engine. The catalytic converter is comprised of first and second three-way catalysts disposed in a casing. The first catalyst is located upstream of the second catalyst relative to the stream of exhaust gas in the catalytic converter. Each catalyst is formed therein with many exhaust gas passages through which exhaust gas passes. Each catalyst includes a honeycomb type monolithic ceramic substrate having many cells each defined by walls in the substrate. At least a part of each cell serves as the exhaust gas passage. A wash coating is formed on the surface of the walls in the substrate and contains cerium. Catalytic noble metals are carried by the wash coating. The amount of the catalytic noble metals, per a unit volume of the catalyst, carried by the wash coating in the first catalyst is more than that in the second catalyst, thereby improving activation promoting characteristics of the first catalyst at low temperatures.
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