SPARK IGNITION DEVICE AND GROUND ELECTRODE THEREFOR AND METHODS OF CONSTRUCTION THEREOF

摘要

A spark ignition device has a ceramic insulator surrounded by a metal shell. The metal shell extends along a longitudinal axis to a distal end. A center electrode is received in the ceramic insulator and extends along the longitudinal axis. A ground electrode has an attachment end fixed by a weld joint to the distal end of the shell and a free end extending from the distal end to provide a spark gap. The weld joint includes a capacitive pulse discharge weld joint and a laser weld joint, which in combination inhibit material expulsion; provide a reliable, strong attachment of the ground electrode to the shell; provide an improved heat transfer path between the ground electrode and the shell, and facilitate repeatable and accurate positioning of the ground electrode to the shell. The weld joint includes a homogeneous mixture of the metal shell and the ground electrode.