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:
Feb. 27, 2007
Filed:
Jan. 31, 2005
Keiji Kanao, Aichi-ken, JP;
Shinichi Okabe, Aichi-ken, JP;
Keiji Kanao, Aichi-ken, JP;
Shinichi Okabe, Aichi-ken, JP;
Denso Corporation, , JP;
Nippon Soken, Inc., , JP;
Abstract
A spark plug according to the invention includes a metal shell that has a threaded portion with an outer diameter of 10 mm or less, or equal to 12 mm, an insulator, a center electrode, and a ground electrode. The spark plug has an improved structure in which an end portion of the insulator tapers toward an end thereof that protrudes from an end of the metal shell, and dimensional parameters, including a space G of the spark gap in the spark plug, a taper degree of the end portion of the insulator that is represented by an outer diameter difference (D−D) in the end portion, and a size Tof the air pocket formed in the spark plug, each have an effective range determined based on the experimental investigation results from the inventors. The structure ensures high insulation properties and high ignition capability of the spark plug.