Patent ID: 7971476

Claim:
A method for identifying various phases of ionization current released during combustion in each cylinder of an internal combustion engine fitted with one or more cylinders, having a control unit, and a device to produce the ionization current (IC) located above each cylinder, comprising a coil, a spark plug, a polarisation circuit and an acquisition circuit, wherein said method comprises the following phases: measurement, in each cylinder of said engine, of the ionization current signal from the end of the spark occurring in the spark plug through to the end of the ionization phenomenon (IC); selection of samples of said ionization current IC signal at predetermined intervals of time within windows which vary from 5 μs to 50 μs (S); registration of the signal samples S; calculation of the value of the derivative of each signal sample S (S 1 ); association of each sample signal S with the corresponding value S 1 ; ordering of the values S 1 in a progressive temporal fashion, starting from the end of the spark occurring in the spark plug through to the end of the ionization phenomenon (S 1 O); comparison of each value S 1 O with the previous value S 1 O and the subsequent value S 1 O; registration of each sample signal S corresponding to the value S 1 O which proves to be essentially equal to zero and preceded by a value S 1 O with a positive value and followed by a value S 1 O with a negative value (P); measurement of each length of time that lapses between the end of the spark occurring in the spark plug and the instant the value P is registered (TP); and registration of the lengths of time TP.