Control device and control method for hybrid vehicle

A control device for a hybrid vehicle, including a unit having an internal combustion engine, a motor, a stepped power transmission and an electric storage device adapted to supply electric power output to the motor, wherein at least one of power outputs of the internal combustion engine and the motor is transmitted through the stepped power transmission to an output shaft thereof, the control device comprising:

• means for detecting an SOC value indicative of a remaining charged capacity of an electric storage device;
• means for calculating a target value of a running efficiency, indicative of a proportion of a given physical quantity, in terms of a drive power rate required for driving the vehicle, in such a manner that the higher the SOC value, the small will be the target value to be calculated;
• means for calculating a target value of a unit operating point, that forms the target running efficiency, from among operating points of a unit which cause the drive power rate provided by an internal combustion engine to be utilized at the running efficiency with the maximum efficiency;
• and
• target unit operating point actualizing means for controlling the unit such that the unit is operated at the target unit operating point.

A control method for a hybrid vehicle, including a unit having an internal combustion engine, a motor, a stepped power transmission and an electric storage device adapted to supply electric power output to the motor, wherein at least one of power outputs of the internal combustion engine and the motor is transmitted through the stepped power transmission to an output shaft thereof, the control method comprising:

• detecting an SOC value indicative of a remaining charged capacity of the electric storage device;
• calculating a target value of a running efficiency, indicative of a proportion of a given physical quantity in terms of a drive power rate required for driving the vehicle in such a manner that the higher the SOC value, the small will be the target value to be calculated;
• calculating a target value of a unit operating point, that forms the target running efficiency, from among operating points of the unit which cause a power rate provided by the internal combustion engine to be utilized at the running efficiency with the maximum efficiency;
• and
• controlling the unit in a way to actualize operation of the unit at the target unit operating point.