Small-sized spark plug having a spark gap parallel to an axis running through the center electrode
US4695758A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Jul 24, 1985 |
| Grant date | Sep 22, 1987 |
| Priority date | — |
| Expiry date | Jul 24, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T13/467
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A small-sized spark plug for internal combustion engines is disclosed which is composed of a center electrode having a shaft portion surrounded by an insulator layer and a terminal end portion adapted to act as a spark generation portion; and an earthed electrode having a terminal end portion which is spaced apart from and is opposite to the terminal end portion of the center electrode so that a spark gap is defined along a surface of the insulator layer. The shortest distance .delta. (mm) between each end portion of the two electrodes and the surface of the insulation layer and the distance l between the forward end portions of the two electrodes have the following relationship: EQU .delta..gtoreq.0.25 l, and 0.8 mm.ltoreq.l.ltoreq.2.0 mm. A recessed portion may be provided on the surface of the insulation layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.