Spark plug with high capability to ignite air-fuel mixture
US7408294B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Aug 5, 2005 |
| Grant date | Aug 5, 2008 |
| Priority date | — |
| Expiry date | Feb 6, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T13/38
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A spark plug according to the invention includes a metal shell, a hollow insulator, a center electrode, and a ground electrode. The insulator has a first end protruding into a combustion chamber of an engine and a second end opposite to the first end in the lengthwise direction of the insulator. The insulator increases in outer diameter from the edge of the inner surface thereof at the first end to a reference plane that is defined to extend perpendicular to the lengthwise direction of the insulator and away 0.1 mm from the edge of the inner surface of the insulator toward the second end of the same in the lengthwise direction. Further, a first volume V1, which is the volume of a portion of the insulator between the edge of the inner surface of the insulator and the reference plane, is in the range of 0.15 to 0.38 mm3.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.