Spark plug for internal combustion engine and related manufacturing method
US7714490B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 6, 2007 |
| Grant date | May 11, 2010 |
| Priority date | — |
| Expiry date | Jun 26, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T21/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A spark plug for an internal combustion engine and related manufacturing method are disclosed having a metal shell, a porcelain insulator, a center electrode and a ground electrode. The center electrode includes a substantially columnar shaped base material body, and a substantially square shaped rod-like Ir alloy tip bonded to a leading end portion of the base material body. The leading end portion has a diameter D2 smaller than a diameter D1 of the base material body. The Ir alloy tip has a square shape with a long diagonal line supposed to form a diameter A of a circumscribed circle CA of the Ir alloy tip whose inscribed circle CB is coaxial with the circumscribed circle CA and has a diameter B, with four diameters A, B, D1 and D2 lay in the relationship expressed as D1>A>D2>B.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.