| 摘要 |
<p>A spark plug 100 includes a ground electrode 40. The cross sectional area S of a ground electrode base member 41 of the ground electrode 40 satisfies a relation 1.8 mm 2 ‰¤ S ‰¤ 3.2 mm 2 . The embedment depth A of a noble metal tip 42 embedded in a second base member surface 412 and the tip thickness B of the noble metal tip 42 measured along the direction in which the noble metal tip 42 is embedded in the second base member surface 412 satisfy a relation 0.4 ‰¤ (A/B) ‰¤ 0.8.</p> |
