Enhanced engine response to torque demand during cold-start and catalyst warm-up

A spark ignited internal combustion engine employs fuel injectors positioned to inject fuel directly into combustion chambers of the engine, and an electronic engine controller (EEC) to control operation of the engine. The EEC implements a routine which controls the quantity of fuel injected, and spark timing by varying a period of time, which is required for advancing the spark timing during switch from a stratified stoichiometric charge combustion by split injection to a homogeneous charge combustion by single injection, with differing degrees of operator torque demand.