Method for adjusting the dosage amount of a reducing agent for selective catalytic reduction

摘要

The method involves determining a correction value based on a portion of metered quantity of a reducing agent upon achieving one of nominal nitrogen oxide concentration and nominal nitrogen oxide conversion, upon establishing presence of ammonia, and upon achieving minimum or predefined value of an actual value of ammonia. The correction value is stored in a memory of a control unit, where the correction value is determined based on the metered quantity before varying the metered quantity. The metered quantity is adjusted by the correction value for subsequent metering processes.