Exhaust gas purification unit used in diesel and gasoline direct injection engines has a switching device for introducing a reducing agent into the exhaust gas stream arranged before or within an oxidation catalyst

摘要

Exhaust gas purification unit comprises an oxidation catalyst (4) arranged in the exhaust gas channel of an I.C. engine, a unit for the selective catalytic reduction of the exhaust gas (29), and a feed unit (8) for introducing a reducing agent (81) into the exhaust gas stream or into the selective catalytic reduction unit. A switching device (83) for introducing the reducing agent (81) into the exhaust gas stream is arranged before or within the oxidation catalyst. An Independent claim is also included for a process for purifying an I.C. engine exhaust gas using the above unit.