A method for operating an engine of a vehicle, the engine having a cylinder with at least a first and second valve, the method comprising during a first mode, operating with the first valve active and the second valve deactivated during a cycle of the cylinder, where during said first mode, the cylinder operates to allow at least air to enter the cylinder during an intake stroke, where the air is mixed with fuel and compressed to attain auto-ignition; and during a second mode, operating with the first and second valves active during a cycle of the cylinder, where during said second mode, cylinder operates to allow at least air to enter the cylinder, where the air is mixed with fuel and ignited via a spark from an ignition plug.