| 摘要 |
<p>The purpose of the present invention is to provide a spark plug that can improve the combustion efficiency of an internal combustion engine. The cross-sectional shape of the middle section (460) of a ground electrode (40) in the spark plug (100) satisfies the relationships of B > (A/2), R1 > r1, and R2 > r2, wherein A represents the length between base point P3 and base point P4 along the X-axis direction, B represents the length along the Y-axis direction from the straight line that connects base point P3 and base point P4 to base point P7, r1 represents the average curvature radius of the first curved section, r2 represents the average curvature radius of the second curved section, R1 represents the average curvature radius of the third curved section, and R2 represents the average curvature radius of the fourth curved section.</p> |
