Spark plug with multiple ground electrodes
US7170219B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Aug 5, 2005 |
| Grant date | Jan 30, 2007 |
| Priority date | — |
| Expiry date | Aug 5, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T13/467
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A spark plug according to the present invention includes a metal shell, an insulator, a cylindrical center electrode, a first ground electrode, and a second ground electrode. The first ground electrode is aligned with the center electrode in the axial direction of the center electrode to form a first spark gap, across which normal sparks are discharged when the insulator is not fouled with carbon. The second ground electrode is aligned with the center electrode in the radial direction of the center electrode to form a second spark gap, across which side sparks are discharged when the insulator is fouled with carbon. The spark plug has an improved structure where dimensional parameters A, T, B, C, L, D, and E are specified to be in suitable ranges that are determined through experimental investigation. The improved structure ensures a high ignition capability and a long service life of the spark plug.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.