| 摘要 |
<p>In a spark plug, a main air gap (A) is formed between a parallel ground electrode (11) and the end face of a central electrode (2), a semi-surface gap (B) is formed between the end face (12C) of a semi-surface ground electrode (12) and the side face (2A) of the central electrode (2) and a semi-surface air gap (C) is formed between the end face (12C) and the side face (1E) of insulator. In addition, difference in a level E between the height of the lower end face (1D) of the insulator (1) and the height of the upper edge (12B) of the end face 12C of the semi-surface ground electrode 12 is E ≤ +0.7 mm, the distance B of the semi-surface gap (B) is longer than the distance A of the main air gap (A) and the distance C of the semi-surface air gap (C) is shorter than the distance A of the main air gap (A). <IMAGE> <IMAGE></p> |
