Patent ID: 7359791

Claim:
An internal-combustion engine, comprising: at least one cylinder; at least one intake pipe and at least one exhaust pipe associated to the cylinder; at least one intake valve and at least one exhaust valve, which control passage through said intake and exhaust pipes; a system for variable actuation at least of the intake valves, first sensor means for detecting the temperature in said intake pipe; second sensor means for detecting the pressure in said intake pipe, upstream of the intake valve; third sensor means for detecting the engine r.p.m.; fourth means for detecting or calculating the temperature in said exhaust pipe; and an electronic control unit pre-arranged for receiving the signals at output from said first, second and third sensor means and for calculating the mass of fresh air taken in by the engine, said engine being wherein said electronic control unit is programmed for calculating the mass of fresh air taken in by the engine on the basis of a calculation of the pressure within the cylinder at the instant of intake valve closing, in which said pressure within the cylinder at intake valve closing is obtained by multiplying the detected pressure value upstream of the intake valve by a pressure factor F: p cyl =p uv ·F p and wherein said pressure factor is a factor pre-determined empirically for said engine uniquely as a function of: the engine r.p.m.; and a parameter, relevant parameter of the valve-lift profile, which is in turn determined empirically, and indicates the profile of the intake-valve lift as the engine angle varies.