Spark plug having ground electrode protruding member with inner and outer edges

Abstract

A spark plug includes a metal shell, an insulator, a center electrode, and a ground electrode. The insulator is retained in the metal shell. The center electrode is secured in the insulator and has an end portion that protrudes from the insulator and has an end edge. The ground electrode includes a base member fixed to the metal shell and a protruding member joined to the base member. The protruding member protrudes from a surface of the base member and has a hollow end face that faces the end portion of the center electrode through a spark gap. The end face of the protruding member has an inner edge and an outer edge, both of which face the end edge of the end portion of the center electrode. With the above configuration, the spark plug can induce spark discharges with a low discharge voltage while securing the ignition capability thereof.

Dependencies are inferred from the claim text.