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.

Date of Patent:
Mar. 17, 2015

Filed:

Mar. 07, 2012
Applicants:

Yasushi Sakakura, Ichinomiya, JP;

Yuichi Matsunaga, Nagoya, JP;

Inventors:

Yasushi Sakakura, Ichinomiya, JP;

Yuichi Matsunaga, Nagoya, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01T 13/20 (2006.01); H01T 21/02 (2006.01); H01T 13/46 (2006.01); H01T 13/32 (2006.01); F02P 13/00 (2006.01);
U.S. Cl.
CPC ...
H01T 13/32 (2013.01); H01T 21/02 (2013.01); H01T 13/467 (2013.01); H01T 13/20 (2013.01); F02P 13/00 (2013.01);
Abstract

A technique of reducing occurrence of multiple discharge in a spark plug. The spark plug has a main ground electrode and three auxiliary ground electrodes. The position at which first auxiliary ground electrode is joined to a metallic shell is located opposite the position at which main ground electrode is joined to the metallic shell, with respect to a center electrode. The positions at which second and third auxiliary ground electrodes are joined to the metallic shell are located opposite to each other with respect to the center electrode. When the width of first auxiliary ground electrode is represented by W, the shortest distance between second auxiliary ground electrode and third auxiliary ground electrode is represented by T, and a distance which is a component of the shortest distance T in a direction orthogonal to first auxiliary ground electrode is represented by Tp, a relation W≧Tp is satisfied.


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