Patent ID: 8826645

Claim:
A system comprising: an engine configured to operate in a first operating state and a second operating state; a particulate filter configured to receive exhaust gas from the engine and filter particulate matter from the exhaust gas; an oxidation catalyst configured to generate heat to increase a temperature of the exhaust gas during a regeneration process; a sensor configured to measure an actual temperature of the exhaust gas during the regeneration process; and a controller configured to: calculate a fuel conversion factor, the fuel conversion factor representing a ratio of a difference between a first expected temperature of the exhaust gas and a second expected temperature of the exhaust gas to a difference between the actual temperature and the second expected temperature of the exhaust gas; integrate the fuel conversion factor during the regeneration process to define an integration value when the engine is operating in the first operating state; at least one of hold the integration value constant and reset the integration value when the engine is operating in the second operating state; compare the integration value to a predetermined value; and provide an indication if the integration value is less than the predetermined value.