Method and device for testing the functionality of an NO oxidation catalyst

摘要

The method involves supplying a nitrogen oxide oxidation catalyst (5) in an exhaust gas stream, and performing a change in concentration of a reducing agent, particularly carbon monoxide. The resulting change of the nitrogen oxides concentration is determined in the nitrogen oxide oxidation catalyst or downstream of the nitrogen oxide oxidation catalyst by nitrogen oxides sensors, while the functionality of the nitrogen oxide oxidation catalyst is evaluated for checking. A defined amount of the reducing agent is supplied to the exhaust stream of an internal combustion engine (1) in the upstream of the nitrogen oxide oxidation catalyst. An independent claim is included for a device for operating the catalyst functionality checking method, has an exhaust pipe and a controller.