Drive power control apparatus and method for vehicle

An engine output for bringing the drive power of a motor vehicle to a requested value is determined as a target output. One of the lean burn and the stoichiometric burn is selected as a combustion form that achieves a best fuel consumption performance in terms of the control of the actual engine output to the target output. That is, an output value that serves as a criterion for determining whether to switch the combustion force is determined based on the minimum fuel consumption rate during the stoichiometric-burn operation and the minimum fuel consumption rate during the lean-burn operation in which the fuel consumption involved in the rich spike control is taken into account. If the target output is less than the output value, the lean-burn operation is performed. If the target output is greater than the output value, the stoichiometric-burn operation is performed.