| 摘要 |
Provided is a spark plug with which depletion of the base material of a grounding electrode can be suppressed, and abnormal combustion can be suppressed. A spark plug 100 comprises: an insulator 10; a main metal fitting 50 covering the outer periphery of the insulator 10; a center electrode 20 which is arranged within a shaft hole 12 of the insulator 10 and a distal end 22a of which is exposed from a distal end section 10a of the insulator 10; and a grounding electrode 30 which has a fixed end 31 fixed to the main metal fitting 50 and a free end 32 spaced apart at a predetermined distance SG from the center electrode 20, and which is provided with an inside surface 30c facing the center electrode 20 and insulator 10. The spark plug is provided with a covering section 80 formed of a noble metal or noble metal alloy and covering at least a region spanning from a first crossing line section including an intersection between the grounding electrode 30 and a virtual line extending from an outer periphery of a center electrode base material 21 on the fixed end side to the grounding electrode 30, to a second crossing line section at which a virtual plane parallel to an end surface of the distal end 22a passing through a midpoint of the predetermined distance intersects with the grounding electrode 30. |
