Abstract: A system and method for reducing rate of increase of NOx feedgas emissions during an acceleration event in a vehicle having an engine with exhaust gas recirculation (EGR) and an electric machine, such as an integrated starter-generator (ISG) coupled to the engine include operating the electric machine to provide an assist torque and reducing engine torque accordingly in response to predicted NOx feedgas emissions exceeding a threshold. The NOx feedgas emissions may be predicted based on an exhaust gas sensor signal or a NOx model based on engine speed, engine torque, and intake EGR ratio. The engine torque may be reduced by reducing an engine torque set point. The electric machine torque may be reduced when a driver demand torque matches the reduced engine torque set point. The electric machine may be used to charge a battery in response to the driver demand torque matching the engine torque set point.

Abstract: 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.

Abstract: A system and method for increasing engine heating rate to facilitate early introduction of exhaust gas recirculation after a cold start include operating an electric machine connect to the engine to apply a load to the engine. The electric machine may be operated as a generator to produce an increased engine torque demand and increase the rate of engine heating until an engine temperature and an exhaust temperature exceed corresponding thresholds. Operation of the electric machine as a generator may be stopped in response to a battery state of charge exceeding a threshold, or engine load exceeding a threshold.

Abstract: A method of removing sulfur from a lean NOx trap of a mild hybrid vehicle while the vehicle is stationary is disclosed, the method comprising connecting an electrical system of the vehicle to a large capacity external battery, operating an integrated starter generator driven by an engine of the vehicle as a generator to load the engine thereby allowing the engine to be operated at a higher torque level and rich of stoichiometric and storing the electrical energy produced by the integrated starter generator in the large capacity battery during the time period required for the removal of sulfur from the lean NOx trap.