Cushman, Darby & Cushman
Spark plug for internal combustion engines
 A spark plug for internal combustion engines includes a third electrode in addition to a center electrode and a ground electrode which define a normal or main spark gap. Defined between the center electrode and the third electrode is an auxiliary gap adjoining the normal gap and adapted to produce a capacitive discharge at a voltage lower than that of the normal gap, and a discharge is induced across the normal gap by the capacitive discharge across the auxiliary gap. 
Nippon Soken, Inc. Toyota Jidosha Kabushiki Kaisha
H H
H01T H01T
inventional inventional
Noboru Toshihiko Kiyohiko Hiroshi Masahiro Takeo
Takagi Igashira Watanabe Hosoi Yamashita Miyoshi