Control of an exhaust gas aftertreatment device in a hybrid vehicle

A method for operating a hybrid propulsion system having an internal combustion engine and an additional power source, the engine having an exhaust gas aftertreatment device (EGAD) coupled to an exhaust of the engine, said method comprising:

• identifying a minimum activation temperature of the EGAD;
• determining that an EGAD temperature is below a threshold temperature selected to prevent the EGAD temperature falling below the minimum activation temperature;
• pumping air to the EGAD when the engine is off by rotating a crankshaft of the engine by said additional power source;
• and
• commanding at least one fuel injector to supply fuel to at least one cylinder of the engine and thereby to the EGAD, wherein an amount of fuel injected is controlled to cause combustion and thereby prevent a temperature within the EGAD dropping below the minimum activation temperature.

A hybrid vehicle propulsion system comprising:

• an internal combustion engine having a crankshaft, at least one cylinder, and an exhaust gas treatment device (EGAD) located downstream of the at least one cylinder;
• an additional power source;
• a fuel storage device;
• a fuel supply device controlling an amount of fuel provided to the engine from the fuel storage device;
• and
• a control unit electronically coupled to the fuel supply device and the additional power source, the control unit comparing an EGAD temperature with a threshold temperature selected in relation to a minimum activation temperature of the EGAD and, if the EGAD temperature is below the threshold temperature, causing the additional power source to rotate the engine while commanding the fuel supply device to provide fuel to the engine when the engine is off, the rotation of the crankshaft and the amount of fuel being controlled to cause combustion within the EGAD.