Control method and control device for hybrid vehicle

A control device for a hybrid vehicle including an internal combustion engine, a motor generator, and a battery, wherein the internal combustion engine includes a variable compression ratio mechanism structured to vary in mechanical compression ratio depending on variation in position of a compression ratio control member structured to move due to driving of an electric actuator, the control device comprising:

• a controller configured to:
• determine whether a state of charge of the battery is equal to or higher than a predetermined level;
• and
• in response to regenerative operation of the motor generator in a state that the state of charge of the battery is equal to or higher than the predetermined level, drive the electric actuator of the variable compression ratio mechanism with rotation of the internal combustion engine stopped, in order to consume generated electric power,
• wherein the electric power consumption is performed by continuously driving the electric actuator during the regenerative operation so as to cause the compression ratio to change upward or downward without following a basic target compression ratio set to achieve a fuel efficiency level depending on engine operation conditions, with use of the electric actuator.