SPARK IGNITION INTERNAL COMBUSTION ENGINE, ITS IGNITION PLUG, ITS CYLINDER HEAD, AND MANUFACTURING METHOD OF CYLINDER HEAD

摘要

PROBLEM TO BE SOLVED: To provide an ignition plug with no housing having a few amount of electrode consumption. SOLUTION: This ignition plug comprises a plug body 1 that has a center electrode 11 supplied with high voltage and an insulator 15 for covering and insulating the outer peripheral surface thereof, and has no housing around an insulator leg section 15a positioned at least on the combustion chamber S side of the insulator. The ignition plug also comprises an annular ground electrode 3 that is annularly disposed on the combustion chamber side of a plug hole 21 for storing the plug body, lies near the outer periphery of the tip 11a of the center electrode exposed from the insulator, and is made of an electrode material different from that of a cylinder head. An spark discharge is performed across a discharge gap formed between the tip of the center electrode and the annular ground electrode, thereby igniting compressed fuel/air mixture. COPYRIGHT: (C)2004,JPO