Electronic ignition system for an internal combustion engine and driving method of the same

A plasma electronic ignition system for an internal combustion engine having a drive shaft and at least one engine cylinder, said system being configured to generate a spark of predetermined duration within said at least one engine cylinder, the plasma electronic ignition system comprising:

• an ignition coil provided with a primary winding and a secondary winding, wherein said primary winding is connectable, by an electrical connection, to a voltage generator device and said secondary winding is connectable to a spark plug;
• a switch connected to said primary winding and drivable to open and/or close said primary winding according to a value of a driving signal, in order to prevent or allow passage of an electric current through said primary winding;
• a control unit associated with said switch and configured to drive said switch to an open and/or closed position according to the value of said driving signal;
• said control unit configured to control said switch by varying a timing and/or a period of opening and closing said switch so that said switching generates, in the secondary winding, an oscillating electric potential adapted to generate and/or maintain active at least an electric arc at terminals of a discharge gap of the spark plug;
• and
• a measuring device configured to measure a parameter representing an ionization process at said discharge gap of the spark plug associated with said secondary winding and arranged to detect a current value in said secondary winding and to send a signal representative of said current value to the control unit;
• wherein said control unit is configured to activate said measuring device upon a shutdown of said electric arc, and
• wherein the control unit is configured to:
• charge said primary winding by closing said switch for a predetermined first time interval;
• power said secondary winding by electromagnetic induction by opening said switch in order to generate the spark at said spark plug:
• subsequently open and close said switch in alternate succession to modulate a duration of said spark;
• detect an angular position of the drive shaft for each revolution;
• open said switch to cancel the voltage on said secondary winding by extinguishing said spark when said angular position corresponds to a preset reference value for said at least one engine cylinder;
• detect the ionization current as a result of said opening of said switch;
• further charge said primary winding and further power said secondary winding via electromagnetic induction, if the ionization current detected is lower than a preset reference value or close to zero, in order to prevent an unburnt mixture from reaching an exhaust pipe.