Sughrue, Mion, Zinn, Macpeak and Seas
Sparkplug with antifouling coating on discharge end of insulator
 A sparkplug having an improved antifouling performance and in which a decrease in insulation resistance is prevented, even if an electrically conductive material is deposited on the firing surface of the insulator of the sparkplug. In accordance with the invention, a coating of a solution of silicone and paraffin is formed on at least the portion of the firing surface of the porcelain insulator which is surrounded by the inner surface of the combustion chamber side of the metal casing of the sparkplug. Preferably, the coating is also formed on the inner surface of the metal casing. 
NGK Spark Plug Co., Ltd.
H F
H01T F02B
inventional additional
Kichio Takahito Shunichi Hisao
Nakahara Yamamota Takagi Mizuno