The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 28, 1992
Filed:
Aug. 08, 1991
Mitsutaka Yoshida, Nagoya, JP;
Akihiro Toya, Nagoya, JP;
Akihisa Harada, Nagoya, JP;
Eigo Goto, Nagoya, JP;
Makoto Sugimoto, Nagoya, JP;
Toru Moriya, Nagoya, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A spark plug for an internal combustion engine is disclosed. A semiconductor material having a resistance of 5.times.10.sup.2 -5.times.10.sup.4 M.OMEGA./mm is coated or baked in the form of a band on the peripheral surface of a basal part of a leg portion of an insulator of the spark plug. Preferably, at least the basal part of the leg portion, including the band, is covered with a water-repellant insulating coating. An inner wall of a metal shell of the spark plug is desirably coated with a water-repellant material at an area facing at least the peripheral surface of the basal part of the leg portion of the insulator.