Resistor built-in spark plug
US4004183A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Apr 30, 1975 |
| Grant date | Jan 18, 1977 |
| Priority date | — |
| Expiry date | Apr 30, 1995 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02B2075/027
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A resistor built-in spark plug comprising an insulator formed therein with an axially extending bore, a terminal nut fitted in an upper end portion of the bore, a center electrode fitted in a lower end portion of the bore, a resistor arranged in a central portion of the bore, one copper-glass electrode interposed between the resistor and the terminal nut, and another copper-glass electrode interposed between the resistor and the center electrode, such resistor being made by firing (calcining) and solidifying a resistor powder mixture consisting of 30 to 10 volume % of a principal resistor component containing tin oxide, 35 to 85 volume % of insulating ceramic filler powder of a higher electric resistivity than the principal resistor component which is selected from the group consisting of quartz glass, alumina, zircon, zirconia, silica (SiO.sub.2) and .beta.-spodumene, and 35 to 5 volume % of glass powder having a softening temperature in a range between 300.degree. and 600.degree. C. One or both of the two copper-glass electrodes may consist of two electrode layers, one copper-glass layer maintained in contact wth the resistor and having a higher copper content than the other copp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.