Method of protecting a diesel particulate filter from overheating

摘要

A method for preventing overheating of a diesel particulate filter during regeneration when an engine is idling may include using an electric machine to apply a load to the engine and compensating for the increase in applied load by increasing an engine torque set point to reduce the concentration of Oxygen in the exhaust gas flowing to the diesel particulate filter. Increased engine torque may be provided by adjusting air-fuel ratio by enriching an air-fuel mixture supplied to the engine and the diesel particulate filter. The control may be initiated in response to entering an idle mode during regeneration or in response to a measured or estimated temperature of the diesel particular filter exceeding a threshold or limit. Estimated temperature may be predicted using a soot combustion model.