| 摘要 |
PROBLEM TO BE SOLVED: To provide a spark plug for an internal combustion engine, capable of suppressing increase of an electric resistance value of a resistor while ensuring a suppression performance of a radio noise.SOLUTION: A spark plug 1 comprises: a cylindrical housing 2; an insulator 3 held in an inside of the housing 2; a center electrode 4; a terminal metal tool 7; a ground electrode 5; and a resistor 6. The center electrode 4 is held in the inner side of the insulator 3 so as to project a tip part. The terminal metal tool 7 is held in the inner side of insulator 3 so as to project a base end part. The ground electrode 5 forms a spark discharge gap G with the center electrode 4. The resistor 6 is disposed in the inner side of insulator 3 between the center electrode 4 and the terminal metal tool 7, and contains a carbon. In the resistor 6, a containing ratio of carbon of a first region 61 of the tip side rather than a center in an axial direction X is higher than that of a second region 62 of the base end side rather than the center in the axial direction X.SELECTED DRAWING: Figure 1 |
