Spark plug and plasma generating device

摘要

To provide a spark plug that can reduce power loss and prevent erosion of a tip end part of a central electrode, even in a configuration such that a discharge current and an electromagnetic wave are emitted from a terminal fitting part of the spark plug, and a plasma generation device using the spark plug. The spark plug is provided with a central electrode 2 including a terminal fitting part 2A and an electrode main body 2B electrically connected to the terminal fitting part 2A, an insulator 3 formed with an axial hole 30, which the central electrode 2 is fitted into, a main fitting 4 that surrounds the insulator 3, and a ground electrode 5 that extends from an end surface of the main fitting 4 and is adapted to form a discharge gap that causes a spark discharge between the central electrode 2 and the electrode main body 2B. The electrode main body 2B is constituted of a front electrode 25 including an electrode tip part 25a for causing the spark discharge with the ground electrode 5, a front dielectric cylinder 24 in a tube-like shape that covers the electrode tip part 25a, and a coupling conductive cylinder 23 in a tube-like shape that joins the front dielectric cylinder 24 and the terminal fitting part 2A.

主权项

1. A spark plug, comprising:
a central electrode including a terminal fitting part electrically supplied from outside and an electrode main body electrically connected with the terminal fitting part; an insulator formed with an axial hole, which the central electrode is fitted into; a main fitting arranged in a manner so as to surround the insulator; and a ground electrode, which extends from an end surface of the main fitting and is adapted to form a discharge gap for a spark discharge with the electrode main body, wherein the terminal fitting part is electrically supplied with a pulse voltage for the spark discharge and an electromagnetic wave provided as energy to the spark discharge, and the electrode main body is constituted of a front electrode including an electrode tip part for causing the spark discharge with the ground electrode, a front dielectric cylinder in a tithe-like shape covering the electrode tip part, and a coupling conductive cylinder in the tube-like shape joining the front dielectric cylinder and the terminal fitting part.