METHOD TO ADJUST AN INTERNAL COMBUSTION ENGINE AND INTERNAL COMBUSTION ENGINE

A method to adjust an internal combustion engine (6) is described, comprising the steps of: i) controlling a first and second adjustment member (20, 21) so as to adjust a first and second quantity of air (Q1, Q2) in a first and second cylinder (10, 11) provided with a first and second piston (15, 16); ii) operating a first and second ignition member (22, 23) with a first and second advance angle (θ1, θ2) relative to the first and second top dead centre (PMI, PMS) of the first and second piston (15, 16); iii) processing a value of one (Ak) of the amplitudes (A1, .. Ak, .. An) associated with a respective frequency (fk) of a driving member (12); iv) detecting that the amplitude (Ak) at a corresponding desired frequency (fk) exceeds a threshold value (Akth); v) reducing the first advance angle (θ1); and vi) increasing the first quantity of air (Q1) so as to maintain the average value (Cavg) of the resulting torque (C, Cadj) constant at two complete rotations of said driving member (12).