Adcat exhaust treatment device
AssigneeGeneral Motors Corporation
InventorsMark D. Hemingway, George A. English
Life of this patent
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Abstract
The invention relates to a catalytic converter system for controlling exhaust emissions from a combustion engine wherein the catalytic converter has three catalysts zones. A zone which is first in line with the direction of the flow of exhaust and which includes a light-off catalyst such as palladium. A second zone in line of the direction of the exhaust flow includes a hydrocarbon adsorber/catalyst. A third zone in line of the direction of the exhaust flow includes a catalyst system converter CO and NO.sub.x. The three-zone system of the present invention produces hydrocarbon efficiencies above 98 percent and retains hydrocarbon efficiencies above 50 percent in cold performance situations immediately after start-up of the combustion engine.
Claims6
A catalytic converter system for controlling vehicle exhaust emissions comprising:
- a catalyst package comprising a substrate;
- said substrate having first, second and third catalytic zones positioned respectively within the direction of exhaust flow traveling through the catalyst system;
- said zones being defined within said substrate by different coatings on said substrate, said first zone having a light-off catalyst coating said second zone having an adsorber/catalyst coating for adsorption of hydrocarbon, said third zone having a catalyst coating for converting CO and No.sub.x constituents in the exhaust flow, and said second zone being immediately adjacent to said first and third zones.
Dependencies are inferred from the claim text.