Method for operating exhaust system of diesel engine, involves evaluating temporally increase of nitrogen oxide flow supplied from selective catalytic reduction catalyzer for closing aging state of catalyzer

摘要

The method involves reducing nitrogen oxide by a selective catalytic reduction (SCR) catalyzer (32). An aging state of the SCR catalyzer is provided for monitoring amount of reducing agent i.e. ammonia, stored in the SCR catalyzer. Efficiency break-down of the SCR catalyzer is detected during a phase change of the amount of the reducing agent stored in the SCR catalyzer. Temporally increase of a nitrogen oxide flow supplied from the SCR catalyzer is evaluated for closing the aging state of the SCR catalyzer. Independent claims are also included for the following: (1) a computer program for operating an exhaust system of an internal combustion engine (2) a control and/or regulating device for operating an exhaust system of an internal combustion engine.