Filtering method for nitrous oxide sensor of exhaust system, involves setting data of nitrous oxide sensor as ammonia measured values when ratio of nitrous oxide modeling error to ammonia modeling error is greater than upper threshold

摘要

The method involves determining (10) the nitrous oxide concentration in upstream and downstream of the selective catalytic reduction (SCR) catalyst. The nitrous oxide conversion and ammonia slip behavior are modeled (14). The errors of the nitrous oxide modeling and ammonia modeling are calculated (17). The data of the nitrous oxide sensor is set (19) as ammonia measured values or nitrous oxide measured values when the ratio of the nitrous oxide modeling error to the ammonia modeling error is greater/smaller than an upper/lower threshold. An independent claim is included for filter.