A cylinder cutoff control apparatus of an engine initiates a cylinder
cutoff mode only when two conditions, namely a low load condition such as
a vehicle cruising condition and an intake valve closure timing
controlled to a given timing value before a bottom dead center, are both
satisfied. A fuel cutoff mode is executed prior to the cylinder cutoff
mode. During a transition to the cylinder cutoff mode, the control
apparatus holds an intake valve open timing at a given timing value
substantially corresponding to a top dead center, simultaneously with
reducing an intake valve lift amount of each intake valve, subjected to
cylinder cutoff control, to a zero lift. Immediately when the intake
valve lift amount is reduced to below a lift threshold value, an exhaust
valve lift amount of each exhaust valve, subjected to the cylinder cutoff
control, is controlled to a zero lift.