INTERNAL COMBUSTION ENGINE SYSTEM

An internal combustion engine system includes an internal combustion engine and a control device. A difference of an intake valve closing timing with respect to a compression top dead center is referred to as a first crank angle difference; a difference of an exhaust valve closing timing with respect to an exhaust top dead center is referred to as a second crank angle difference; and a difference between the first crank angle difference and the second crank angle difference is referred to as an intake/exhaust closing timing difference. The control device is configured to execute: a fuel cut processing; and a valve driving processing to control at least one of the intake valve closing timing and the exhaust valve closing timing such that the intake/exhaust closing timing difference becomes smaller during a fuel cut operation than during a non-fuel cut operation.