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:
Nov. 13, 2001

Filed:

Dec. 02, 1999
Applicant:
Inventors:

Yasutake Ishino, Kariya, JP;

Hironori Osamura, Chiryu, JP;

Makoto Yatou, Toyota, JP;

Assignee:

Denso Corporation, Kariya, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01T 1/346 ;
U.S. Cl.
CPC ...
H01T 1/346 ;
Abstract

In a spark plug having a center electrode, first and second ground electrodes, an insulator and a metal housing, a first discharge gap is constituted between a front end of the center electrode and a front side of the first ground electrode and a second discharge gap is constituted between a front end of the second electrode and a front side of the center electrode. Respective dimensional relationships of A, B, C, H, F and L1 are defined where A is a distance of the first discharge gap, Bis a shortest distance between the front end of the second ground electrode and the insulator, C is an axial length from a leading end of the metal housing and a front end of the insulator, H is an axial length from the front end of the insulator and the front end of the center electrode, F is an axial length from the front end of the insulator to the front end edge of the second electrode and L1 is a shortest axial length from the leading end of the metal housing to the front end of the second ground electrode.


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