| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a spark plug capable of quickly burning off carbon adhering to an insulator. <P>SOLUTION: A spark plug includes an insulator 10 and a center electrode 20, in which a projection amount H (mm) and the volume Vi (mm<SP POS="POST">3</SP>) of a tip side of the insulator 10, and the volume Vc (mm<SP POS="POST">3</SP>) of a tip side of the center electrode 20, are defined to improve temperature rise performance in the tip side of the insulator 10. As a result, while maintaining the voltage withstanding properties of the insulator 10 and durability of the center electrode 20, recoverability from carbon contamination can be improved. The improvement in the recoverability from carbon contamination prevents a transverse flying spark from the center electrode 20 to a main metal fitting 50 through the insulator 10 from occurring, so that normal ignition of a gaseous mixture can be stably secured. <P>COPYRIGHT: (C)2013,JPO&INPIT |
