| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a spark plug having a resistance in which increase of a change rate of an electric resistance value is restricted, and in which generation of current noise is prevented by containing titanium oxide powder coated with an insulating oxide in a composition of the resistance. SOLUTION: A spark plug having a resistance is composed of an insulator 3 held on a main body metal 2, a grouding electrode 4 connected to a tip of the main body metal 2, a center electrode 5 forming a spark discharge gap to a discharge end surface of the grounding electrode 4, a terminal electrode 6 connected to a spark coil, conductive glass seal materials 7, 8 filled in the insulator 3, and a monolithic resistance 9 enclosed between the conductive glass seal materials 7, 8. The resistance 9 has composition comprising glass powder, titanium oxide powder, carbon black, and organic binder. The titanium oxide power is contained by 2-60weight%. The surface of the titanium oxide power is coated with insulating oxide film. The grain size of the titanium oxide powder is desirably about 0.1-2μm.</p> |
