A vehicle includes a motor/generator, a disconnect clutch disposed between
the engine and the motor/generator, and a transmission disposed between
the motor/generator and the vehicle drive wheels. The transmission
includes an input clutch which is selectively engagable for facilitating
torque transfer between the motor/generator and the vehicle drive wheels.
When an engine start is requested, the motor/generator is operated, and a
start mode for the engine is determined based on a number of vehicle
parameters. The transmission input clutch is partially disengaged to at
least partially isolate the vehicle drive wheels from engine torque
disturbances when the engine is started. The disconnect clutch is
engaged, and the engine is fueled, thereby facilitating torque production
by the engine.