A method for controlling the launch of a vehicle having a powertrain that
includes a first power path for driving a first wheel set and including
an engine, a transmission having an input driveably connected to a
crankshaft of the engine, a current gear, an input clutch associated with
the current gear and an output connected to first wheel set, and a second
power path including an electric machine for driving a second wheel set.
The method includes determining a desired magnitude of wheel torque to be
produced at the first wheel set, using the desired magnitude of wheel
torque to be produced at the first wheel set to determine a magnitude of
crankshaft torque, producing a predetermined magnitude of torque capacity
at the input clutch, determining a crankshaft speed error, determining a
change in magnitude of torque at the crankshaft that will reduce the
crankshaft speed error, and operating the engine to produce a desired
engine torque, whose magnitude is determined from the change in magnitude
of torque at the crankshaft and the magnitude of desired crankshaft
torque.