Patent ID: 10329982

Abstract:
A method, control system, and vehicle system configured to control a selective catalyst reduction (SCR) system subtracts an amount of NOx present in a tailpipe upstream of the SCR system from an amount of NOx present in the tailpipe downstream of the SCR injector. A cumulative difference may be determined based on integrating the subtracted NOx value. The method, control system, and vehicle system are configured to determine whether the cumulative difference exceeds a control threshold, and to set a selected upstream NOx value as a predetermined model upstream NOx amount if the cumulative difference exceeds the control threshold, but to set the selected upstream NOx value as the determined upstream NOx amount if the cumulative difference does not exceed the control threshold. Thus, the system is reset to the model when downstream NOx values exceed upstream NOx values above a threshold, to bring the system back within control.