Spark plug with small spark gap and flat ignition element surfaces

A spark plug with a longitudinal axis, comprising:

• a housing with a bore along the spark plug longitudinal axis and a combustion-chamber-side end face;
• an insulator disposed at least partly inside the housing;
• a center electrode disposed at least partly inside the insulator and having a base body and a first ignition element;
• and
• at least one ground electrode that is disposed inside the housing and has a base body and a second ignition element,
• wherein the at least one ground electrode and the center electrode are disposed such that the second ignition element of the at least one ground electrode and the first ignition element of the center electrode form a spark gap which extends radially with respect to the spark plug longitudinal axis,
• wherein a surface of the first ignition element of the center electrode which serves as ignition surfaces and a surface of the second ignition element of the ground electrode which serves as ignition surfaces are flat surfaces, and
• wherein a width of the spark gap is given by a spacing between oppositely disposed ignition surfaces of the ground electrode and the center electrode, wherein the width of the spark gap is not greater than 0.3 mm, and the spark gap is formed inside the housing,
• wherein the base body of the center electrode includes at least one recess at a combustion chamber-facing end, in which the first ignition element is directly disposed by welding or melting or indirectly disposed on an intermediate piece positioned within the recess, wherein the recess is a blind hole, a flat surface, or a groove configured radially on the base body.