Patent ID: 9144772
Filing Date: 2015-09-29
Classification: B01D,F01N,Y02T

Abstract:
1. A method for monitoring an SCR catalyst ( 12 ), characterized in that superstoichiometric metering ( 69 ) of reducing agent into the SCR catalyst ( 12 ) is performed for diagnostic purposes, and the storage capacity of the SCR catalyst ( 12 ) is inferred in accordance with at least one characteristic value, which is dependent on a nitrogen oxide conversion rate of the SCR catalyst ( 12 ), wherein a conditioning phase ( 67 ) for setting a specifiable operating point ( 35 ; 68 ) is carried out before the superstoichiometric metering ( 69 ) of the reducing agent, and in that, to set the specifiable operating point ( 35 ; 68 ) in the conditioning phase ( 67 ), substoichiometric metering of the reducing agent is performed until the nitrogen oxide conversion rate of the SCR catalyst ( 12 ) has a negative gradient and a non-zero value at or below 0.5.