Spark plug configured to reduce the occurance of flashover
US8791627B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 2013 |
| Grant date | Jul 29, 2014 |
| Priority date | — |
| Expiry date | Sep 24, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T13/36
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A spark plug includes an insulator, and a metal shell disposed at an outer periphery of the insulator and including a shoulder. The insulator includes a trunk portion, and a leg formed at the tip end side of the trunk portion. The shoulder of the metal shell includes a first shoulder, and a second shoulder formed at the tip end side of the first shoulder. A distance Da between the tip end of the second shoulder and the leg and a distance Db between the tip end of the trunk portion and the second shoulder satisfy a relationship of Da/Db≧1.1. A distance T between the rear end of the first shoulder and the tip end of the second shoulder and a distance L between the rear end of the first shoulder and a tip end face of the metal shell satisfy a relationship of T/L≦0.5.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.