| 摘要 |
PROBLEM TO BE SOLVED: To solve problem of a conventional ignition plug wherein when microwave is emitted from the center electrode of the ignition plug to generate plasma in the case of generating plasma by reacting an electric field with a spark ignition and igniting an air-fuel mixture, if the direction of a high-frequency field by the microwave is aligned with the center axis direction of the center electrode, namely, the discharge direction of a spark discharge, the action of the field on the spark discharge becomes small, and predetermined effects cannot be expected.SOLUTION: This ignition plug of a spark-ignition internal combustion engine includes a center electrode 14 installed in a housing while being insulated and a grounding electrode 15 attached to the bottom end of the housing apart from the center electrode. The plasma is generated by reacting the spark discharge generated between the center electrode and the grounding electrode with the electric field generated in a combustion chamber to ignite the air-fuel mixture. The grounding electrode is disposed so that the end thereof is positioned apart from the center axis of the center electrode. The grounding electrode includes a specific surface 21 which causes the direction of the electric field in the direction crossing the direction of the spark discharge produced between the center electrode and the grounding electrode. |
