A system and method for determining a commanded engine and motor torque to
minimize fuel consumption and manage battery state of charge in a hybrid
electric vehicle. The method includes determining a penalty factor value
that dictates the usage of the battery. A cost value is determined for
every feasible engine torque for a selected or demanded vehicle torque
and speed request. Each cost value is determined by a fuel consumption
value, a change in the battery state of charge and the penalty factor
value. The change in the battery state of charge is determined from the
motor power and a nominal battery state of charge. For a specific penalty
factor, a look-up table for optimal engine torque is generated for
different requested vehicle torques at various vehicle speeds. A separate
look-up table is provided for each penalty factor.