Spark plug for internal combustion engine

摘要

A spark plug for an internal combustion engine disclosed herein includes a resistive semiconductor body connecting a center electrode and an earth electrode to perform a creeping discharge at low discharge voltages while keeping adequate ignition performances. According to the invention, the spark plug comprises a back electrode at the back of a discharging gap to cause the creeping discharge on surfaces of an electric insulator which is resistant to electrolytic corrosion, thereby improving the durability of the plug and eliminating the trouble of electric waves of noises.