Patent ID: 8131437

Claim:
Method for operating a powertrain system comprising a multi-cylinder engine coupled to a hybrid transmission, the engine selectively operative in one of a plurality of main engine states to transfer engine torque to the hybrid transmission, the method comprising: monitoring an operator torque request; determining a preferred main engine state and a preferred engine torque associated with the preferred engine state, wherein the main engine states include a fueled, all-cylinder engine state, a fuel cutoff, all-cylinder engine state, a fueled, cylinder deactivation engine state, and a fuel cutoff, cylinder deactivation engine state and wherein the preferred main engine state comprises a selected one of the main engine states; determining an engine state transition path from a present main engine state to the preferred main engine state including an engine transition state; and executing the engine state transition path between the present main engine state and the preferred main engine state and adjusting engine torque to the preferred engine torque.