A method of controlling a piston-type internal-combustion engine having a cylinder, first and second intake ports opening into the cylinder, as well as first and second intake valves disposed in the first and second intake ports, respectively, for controlling admission of fuel into the cylinder. The method includes injecting fuel simultaneously into the first and second intake ports during operational cycles of the cylinder; at low engine load operating solely one of the first and second intake valves, while maintaining the other of the first and second intake valves inoperative. The operating step is alternated such that the first and second intake valves are alternatingly in an operative and in an inoperative state during consecutive operational cycles of the cylinder.