DOUBLE IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES, IGNITION PLUG FOR DOUBLE IGNITION SYSTEMS, AND ELECTRIC SPARK GENERATOR

摘要

A double ignition spark plug has a cavity which is evacuated of substantially all gases. The insulation portion of the spark plug is formed in two steps at a temperature of 800 to 1000.degree.C where the first sintering step is when the cavity is open and a first conductor is in place, and a second sintering step is effective to close the cavity and fix a second conductor in place. At least the second sintering step is conducted in a vacuum. The completed double ignition spark plug has substantially all gases removed from the spark gap within the insulator.