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:
Dec. 26, 2000
Filed:
Jul. 30, 1998
Kenji Ishida, Nagoya, JP;
Yoshihiro Matsubara, Yokkaichi, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A spark plug (1) comprises a center electrode (5), an insulator (3), a metallic shell (2), and a ground electrode (6). The center electrode (5) comprises a body portion (12) having a cylindrical peripheral surface and a front-end-side opposing face (11) opposed in generally parallel to a side face of the ground electrode (6), and a protruding portion (15) which is protruded from the front-end-side opposing face (11) at a position decentered toward one side opposite to the ground electrode (6) with respect to a center axis line of the body portion (12) and which has a top face (14) formed generally parallel to the side face of the ground electrode (6). Then, given a length D of a line segment formed by an intersection that an imaginary plane including the center axis line of the body portion (12) and a center axis line of the ground electrode (6) intersects the front-end-side opposing face (11), and a protruding height h to which the protruding portion (15) protrudes from the front-end-side opposing face (11), a value of h/D is set to not less than 0.2. As a result, mixed air can be smoothly fed to around a spark discharge gap g, and moreover the flame extinction phenomenon becomes unlikely to occur. Thus, a spark plug superior in ignitability can be realized.