| 摘要 |
PROBLEM TO BE SOLVED: To provide a simply structured spark plug for an internal combustion engine, capable of securing stable ignitability regardless of a mounting attitude to the internal combustion engine.SOLUTION: A spark plug 1 has a cylindrical housing 2, a cylindrical insulator 3 held on the inside of the housing 2, a center electrode 4 held on the inside of the insulator 3 so that a tip part 41 thereof protrudes, a grounding electrode 5 protruding toward the tip side from a tip part 21 of the housing 2 and forming a spark discharge gap G between itself and the center electrode 4, a confronting projection 23 protruding to the tip side from the tip part 21 of the housing 2 at a position opposite to the grounding electrode 5 with the center electrode 4 held between, an electrode side air guiding projection 22 protruding to the tip side from the tip part 21 of the housing 2 at a position nearer to the grounding electrode 5 than to the confronting projection 23, and a confronting air guiding projection 24 protruding to the tip side from the tip part 21 of the housing 2 at a position nearer to the confronting projection 23 than to the grounding electrode 5. |
