Radiofrequency plasma spark plug

A spark plug, configured to equip a combustion chamber of an internal combustion engine, comprising:

• an annular shell having a main axis, the annular shell being comprised of a first conducting material and including a first end, a second end, and an end circular surface having a main axis of symmetry, the end circular surface located at the first end of the annular shell;
• a central electrode comprised of a second conducting material, the central electrode extending along the main axis of the annular shell and including an internal portion positioned inside the annular shell and an external portion protruding out of the first end of the annular shell;
• and
• an electrically insulating component of annular shape inserted between the annular shell and the central electrode, the electrically insulating component covering at least a part of the internal portion of the central electrode extending from the first end of the annular shell toward the second end of the annular shell, and covering only a part of the external portion of the central electrode protruding out of the first end of the annular shell such that an uncovered end part of the external portion is in contact with a gaseous mixture surrounding the spark plug;
• wherein the electrically insulating component comprises an annular shoulder masking the entire end circular surface of the annular shell from the uncovered end part of the external portion of the central electrode, and wherein the spark plug is configured to create a branched plasma in the combustion chamber between the uncovered end part of the external portion of the central electrode and walls of the combustion chamber.