INTERNAL-COMBUSTION ENGINE CONTROL METHOD AND CONTROL DEVICE

An internal-combustion engine includes a variable compression ratio mechanism for changing a mechanical compression ratio, and a variable valve timing mechanism for changing the valve timing of an intake valve. When acceleration is demanded, a target compression ratio is set to a lower compression ratio than the target value in a normal condition, and the valve timing is set to the advance angle side. Since the allowable combustion pressure decreases in a prescribed intermediate compression ratio region, if an actual compression ratio exists in the prescribed intermediate compression ratio region in the course of a compression ratio change accompanying acceleration, the variable compression ratio mechanism restricts the intake pressure by increasing a degree of opening of a wastegate valve or reducing a degree of opening of a throttle valve, for example.