Resistor built-in spark plug
US3967230A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Oct 22, 1974 |
| Grant date | Jun 29, 1976 |
| Priority date | — |
| Expiry date | Oct 22, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T13/41
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A resistor built-in spark plug comprises an insulator formed with an axially extending inner hole, a stem fitted in the upper part of said hole in said insulator, a center electrode fitted in the lower part of said hole, a resistor disposed in the central part of said hole, and copper-glass electrode layers disposed between said resistor and said stem and between said resistor and said center electrode. Said resistor is made by firing and solidifying powder of resistor mixture consisting of 75 to 38 volume percent of main resistor component containing tin oxide and 25 to 62 volume percent of glass powder with softening temperature of 300.degree. to 600.degree.C. Said copper-glass electrode layers are made by firing and solidifying a mixture of copper powder and glass powder with the softening temperature of above 530.degree.C and more than 30.degree.C higher than the softening point of glass in the resistor portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.