Title:
SPARK PLUG
Document Type and Number:
WIPO Patent Application WO/2018/055833
Kind Code:
A1
Abstract:
The objective of the invention is to provide a spark plug capable of improving accuracy in detecting pre-ignition which is caused by a flame kernel occurring inside a spark plug. In the invention, a terminal is disposed more toward the rear end than the threaded portion of a main body metal shell. A detection electrode is disposed in a space sandwiched between the outer periphery of an insulator and the inner periphery of the main body metal shell at a portion that is more toward the forward end than the forward end of a contact portion between a reduced diameter portion and a platform portion or a gasket. The detection electrode and the terminal are linked through a conductor. The detection electrode and the conductor are insulated from a center electrode, the main body metal shell, and a grounding electrode. Since the detection electrode is disposed in the space between the outer periphery of the insulator and the inner periphery of the main body metal shell, a flame kernel that occurs in this space can be detected early.
Inventors:
KANO MASARU (JP)
MORI KIYOTERU (JP)
IWATSUKA TOMOHIRO (JP)
INOUE YOSHIKI (JP)
NAKAGAWA KEITA (JP)
MORI KIYOTERU (JP)
IWATSUKA TOMOHIRO (JP)
INOUE YOSHIKI (JP)
NAKAGAWA KEITA (JP)
Application Number:
PCT/JP2017/018948
Publication Date:
March 29, 2018
Filing Date:
May 22, 2017
Export Citation:
Assignee:
NGK SPARK PLUG CO (JP)
International Classes:
H01T13/40; F02P13/00; H01T13/20; H01T15/00
Foreign References:
| JPS58140986A | 1983-08-20 | |||
| JPS5894295U | 1983-06-25 |
Attorney, Agent or Firm:
AOKI Noboru et al. (JP)
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