| 摘要 |
A spark plug having a length for an internal combustion engine is provided which is designed to keep the ignitability of a gaseous fuel high to decrease a rise in voltage required by the spark plug to discharge, thereby prolonging the service life of the spark plug. The spark plug includes noble metal chips joined to a ground electrode and a center electrode to define a spark gap therebetween. At least one of the noble metal chips has a length of 0.3 mm or more and includes a portion whose sectional area traversing a lengthwise direction of the spark plug is greater than an area of a top end surface, thereby ensuring a higher degree of ignitability of the fuel and minimizing the rate of the rise in the required voltage.
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