Patent ID: 7291093

Claim:
A power output apparatus that outputs power to a drive shaft, said power output apparatus comprising: an internal combustion engine that outputs power to the drive shaft; a motor that inputs and outputs power; a transmission mechanism that converts the output power of the motor at a selected gear ratio and transmits the converted power to the drive shaft; an accumulator unit that transmits electric power to and from the motor; a required driving force setting module that sets a required driving force to be output to the drive shaft; an operation stop prohibition module that prohibits operation stop of the internal combustion engine when the selected gear ratio in the transmission mechanism is a reduction gear ratio for reduction of a rotation speed of a rotating shaft of the motor and transmission of the converted power with the reduced rotation speed to the drive shaft and is not greater than a preset reference level, which is less than a maximum possible reduction gear ratio of the transmission mechanism; and a driving force control module that, in the case of prohibition of the operation stop of the internal combustion engine by said operation stop prohibition module, controls the internal combustion engine, the motor, and the transmission mechanism to keep the internal combustion engine in load operation and to output a driving force equivalent to the required driving force to the drive shaft, in the case of no prohibition of the operation stop of the internal combustion engine by said operation stop prohibition module, said driving force control module controlling the internal combustion engine, the motor, and the transmission mechanism to cause intermittent operation of the internal combustion engine and to output the driving force equivalent to the required driving force to the drive shaft.