Spark plug

A spark plug with a longitudinal axis x, comprising:

• a housing having an end face on a combustion chamber side;
• an insulator which is disposed at least partly inside the housing;
• a center electrode which is disposed at least partly inside the insulator and has an electrode body and an ignition element that is disposed on an combustion chamber-side end of the electrode body and serves as an ignition surface, wherein the ignition element has a cylindrical shape with a round base and a longitudinal axis which extends parallel to the spark plug longitudinal axis;
• and
• at least one ground electrode having an ignition surface, which is disposed inside the housing on the housing;
• wherein the at least one ground electrode and the center electrode are disposed such that the at least one ground electrode and the center electrode form a spark gap that extends radially with respect to the spark plug longitudinal axis;
• wherein a width of the spark gap is given by an electrode spacing between the center electrode and the at least one ground electrode;
• wherein the electrode spacing between the center electrode and the at least one ground electrode is not greater than 0.3 mm, and the spark gap is completely inside the housing;
• and
• a projection of the ignition surface of the at least one ground electrode fits completely onto the ignition element of the center electrode in an axial direction,
• wherein an end of the projection of the ignition surface of the at least one ground electrode facing away from the combustion chamber on the ignition element of the center electrode is spaced apart in axial direction from an end of the ignition element of the center electrode facing away from the combustion chamber, a spacing between the projection and the end of the ignition element being at least 5% of a length of the ignition element.