Method of controlling catalyst light-off of a hybrid vehicle

A method of warming a catalyst of an exhaust gas treatment system of a hybrid vehicle having an engine and an electric motor, the method comprising:

• transitioning a rotational speed of the engine to within a pre-defined speed range with the electric motor;
• reducing an engine manifold pressure to within a pre-defined pressure range;
• fueling the engine after the rotational speed of the engine is within the pre-defined speed range and the engine manifold pressure is within the pre-defined pressure range;
• increasing the engine manifold pressure to within a catalyst light-off pressure range while the engine is being fueled;
• and
• increasing torque output of the engine to within a catalyst light-off operating torque range while the engine is being fueled;
• wherein exhaust gas produced from the operation of the engine within the pre-defined speed range, within the catalyst light-off pressure range, and within the catalyst light-off operating torque range heats the catalyst while minimizing emissions.