Spark plug for internal combustion engine
US7105990B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 8, 2003 |
| Grant date | Sep 12, 2006 |
| Priority date | — |
| Expiry date | Apr 8, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T13/39
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Carbon fouling adhered on an insulator tip of a spark plug of the present invention is burnt down by a leak current during an inductive discharge period, due to a promoted ionization before beginning a capacitive discharge, in such an arrangement of a central electrode that a border portion of a body and narrowed portion is positioned in an insulator. The carbon burning-down effect is further improved by a narrow projection provided with an earth electrode, due to increased inductive energy and extended inductive discharge time period. This is because an electric field in a discharge gap is raised, thereby decreasing a discharge voltage and suppressing an energy emitted from a coil during the capacitive discharge.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.