Patent ID: 8307793

Claim:
An internal combustion engine, comprising at least two intake valves per engine cylinder, each provided with respective return springs which push the valves towards a closed position, wherein the intake valves of each engine cylinder are controlled by a single cam of an engine camshaft, via a single tappet actuated by said cam and through a hydraulic system comprising a master cylinder, having a piston operatively connected to said tappet and two hydraulic actuators respectively associated with the two intake valves and both hydraulically connected to a common pressure chamber of said master cylinder, wherein the return springs associated with the two intake valves of one and the same engine cylinder are arranged so as have an accurately predetermined and controlled difference in load and/or flexibility, so that said intake valves of each cylinder have lift profiles which are different from each other, and so that at each crank angle of the engine the average of the values h 1 and h 2 of the lifts of the two valves equals the theoretical lift h which each valve would show in case of springs with equal load and flexibility.