| 摘要 |
<p>To provide a spark plug including a ground electrode which has an excellent heat sinking ability. A ground electrode 30 includes a core material 35 therein. In a front end portion 31 of the ground electrode 30, a segment BFGHE assumes a generally "M" shape and forms a part of an outline of the core material 35 defined by projecting the core material 35 onto an inner face 33 which is located opposed to a center electrode. Since the outline of the core material 35 assuming such a shape extends close to an outer circumference face of the ground electrode 30 on the further front end side of the front end portion 31, heat received from a combustion chamber during a drive of an internal-combustion engine can be conducted to the core material 35 from a position close to the outer circumference face on the further front end side of the ground electrode 30. As a result, more effective heat sinking ability can be achieved.</p> |
