Method and apparatus for controlling engine shutdown in hybrid vehicles

A hybrid vehicle is provided that includes a control system that controls the time required for engine shut down. An electric machine or integrated starter-generator may be used to apply a load to the combustion engine after an engine shut down signal is received. By reducing the time required to shut down the engine in a controlled manner, the catalytic converter can be conditioned by providing a desired volume of air and fuel to the catalyst to reduce emissions and increase fuel economy. If an indication is received that it is no longer desirable to shut down the engine, the engine may be restarted conventionally or started in a quick start mode by refueling the engine is the engine operating at a sufficient speed for a quick restart.