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:
Oct. 16, 2007
Filed:
Nov. 12, 2004
Hiromi Hiramatsu, Kariya, JP;
Hiromi Hiramatsu, Kariya, JP;
Denso Corpoartion, Kariya, Aichi-Pref., JP;
Abstract
A spark plug according to the invention includes a tubular metal shell, a cylindrical insulator, a plurality of center electrodes, and a plurality of ground electrodes. The meal shell has an end portion in which a plurality of thick-walled portions and a plurality of thin-walled portions are formed. The insulator is fixed in the metal shell. The center electrodes each are retained within one of a plurality of axial bores in the insulator. The ground electrodes each are joined to one of the thick-walled portions to ensure sufficient strength of the ground electrodes. The thin-walled portions each have an inner surface that is outwardly recessed in an angular range including the intersection of the inner surface with a reference line, thereby securing sufficient air pocket size of the spark plug. Accordingly, the spark plug has a high capability to ignite the air-fuel mixture and sufficient strength of the ground electrodes.