Spark plug, insulator for spark plug and process for fabricating the insulator
US6265816A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1999 |
| Grant date | Jul 24, 2001 |
| Priority date | — |
| Expiry date | Apr 29, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T13/38
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention provides a spark plug having an insulator which is composed mainly of alumina, and which is more superior in voltage endurance characteristics at high temperatures as compared with the prior-art materials. An insulator 2 of a spark plug 100 is made of an insulating material which is composed mainly of alumina, and which contains Al component within a range of 95 to 99.7 wt % in weight converted to Al.sub.2 O.sub.3, and in which an area ratio occupied by alumina base principal-phase particles with particle size not less than 20 .mu.m is not less than 50% as a cross-sectional structure of the insulator is observed. By making the alumina base principal-phase particles appropriately coarse like this, the voltage endurance characteristics of the insulator can be remarkably improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.