| 摘要 |
<p>Provided is a spark plug (1) for an internal combustion engine, the spark plug (1) being provided with a housing (2), an insulator (3), a center electrode (4), and a ground electrode (5). A protrusion (6) protruding towards a spark discharge gap (11) is formed on the tip of the center electrode (4) and/or the opposing part (52) of the ground electrode (5). The cross-sectional shape, which is orthogonal to the plug axial direction, of at least one protrusion (6) is in a specific shape having a minimum curvature radius part (61) and satisfying a predetermined condition. Assuming a first straight line (L1), a first line segment (M), and a second straight line (L2), the condition is a condition in which when the cross-sectional shape is divided into a first region (B) and a second region (C) by means of the second straight line (L2), the area of the second region (C) is larger than the area of the first region (B).</p> |
