Patent ID: 8826644

Claim:
A method of controlling an internal combustion engine and exhaust system including an SCR, comprising: monitoring a filter element in the path of the exhaust gas flow to detect an obstruction in the exhaust gas flow; determining, in real time, a NOx conversion efficiency of an exhaust flow output by the internal combustion engine through the SCR, the determining of the NOx conversion efficiency based, at least in part, on received data from a sensor downstream of the SCR at a predetermined sample rate during operation of the internal combustion engine; determining, using a processor, an excess efficiency margin based on a difference between the determined NOx conversion efficiency and a predetermined target conversion efficiency, said target conversion efficiency based on a predetermined allowable amount of NOx emission; and responsive to the determined excess efficiency margin, increasing a NOx concentration level in the exhaust flow by an amount based on the determined excess efficiency margin by decreasing an EGR flow rate to regenerate the filter element.