SCR METHOD FOR CORRECTING MODELED AMMONIA MASS FLOW RATE AND MODELED NITROGEN OXIDE MASS FLOW RATE AND METHOD FOR CONTROLLING SCR-CATALYTIC CONVERTER SYSTEM

摘要

The present invention relates to a method for correcting (78, 79) a modeled ammonia mass flow rate (q_NH3 modeling) and a modeled nitrogen oxide mass flow rate (q_NOx modeling) between two SCR-catalytic converters continuously arranged within an exhaust gas line in an SCR-catalytic converter system. The SCR-catalytic converter system includes only one reducing agent metering unit upstream of the two SCR-catalytic converters. A first sum value (S_1) is calculated through the sum (74) of the modeled ammonia mass flow rate (q_NH3 modeling) and the modeled nitrogen oxide mass flow rate (q_NOx modeling). A second sum (S_2) is calculated from a signal (q_NH3/NOx measurement) of a sensor arranged between the two SCR-catalytic converters and sensitive to ammonia and a nitrogen oxide. The ratio (V) of the two sum values (S_1, S_2) is calculated for the correction (78, 79). In a method for controlling (80) an SCR-catalytic converter system (20), the modeled ammonia mass flow rate (q_NH3 modeling) and the modeled nitrogen oxide mass flow rate (q_NOx modeling) between the two SCR-catalytic converters are corrected by the correction method.