US Patent 7652413 Spark plug for internal combustion engine

Patent 7652413 was granted and assigned to Denso on January, 2010 by the United States Patent and Trademark Office.

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Is a

Patent

Patent attributes

Current Assignee

Denso

Patent Jurisdiction

United States Patent and Trademark Office

Patent Number

7652413

Date of Patent

January 26, 2010

Patent Application Number

11907447

Date Filed

October 12, 2007

Patent Primary Examiner

‌

Peter Macchiarolo

Patent abstract

A spark plug fitted to a cylinder head has a center electrode with a noble metallic tip portion having a sectional area S1 between 0.07 mm2 and 0.95 mm2 and a melting point of 2000° C. or more, and a ground electrode with a noble metallic tip portion having a sectional area S2 and a melting point of 1700° C. or more. The plug has a length H ranging from 6.5 mm and 10 mm between the head and the tip portion of the center electrode, a length G ranging from 1.1 mm and 2.0 mm between the tip portions, a length J between the head and a housing, a length F satisfying J≦F≦H−1.0 mm between the head and an insulator, and a pocket clearance P satisfying P≧1.1×(G+0.0345×S1−1.2418+0.0327×S2−1.2418) between the housing and the insulator.