An exhaust gas purification system for the reduction of the hydrocarbon - emissions during the cold start of combustion engines

摘要

The invention relates to an exhaust gas purification system for decreasing the emissions of hydrocarbons during the cold start of internal combustion engines. The exhaust gas purification system contains a hydrocarbon adsorber and a downstream catalyst system which can be composed of a single three-way catalyst or of a combination of oxidation, reduction and/or three-way catalysts in one or more beds. The hydrocarbon emissions during the cold start phase can be significantly decreased by using oxidation catalysts or three-way catalysts which, in comparison with conventional catalysts, have at least twice the loading of platinum and/or palladium.