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:
Jan. 08, 2013
Filed:
Oct. 01, 2009
Hiroyuki Kameda, Aichi-gun, JP;
Kohei Katsuraya, Nagoya, JP;
Hiroyuki Kameda, Aichi-gun, JP;
Kohei Katsuraya, Nagoya, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
It is an object of the present invention to provide a spark plug that can be produced at low cost and secure compatibility between ignition performance and durability. The spark plug according to the present invention includes a center electrode and a ground electrode having an inner surface facing the center electrode, characterized in that; the ground electrode has a protrusion and a hole; the protrusion protrudes from the inner surface by a protruding length A of 0.4 to 1 mm and has a first straight portion with a projected first straight portion area Sof 1.5 to 3 mm; the hole has an opening at an outer surface of the ground electrode, a second straight portion, a bottom portion and a transition portion; the opening is formed in such a manner that the ratio (S/S) of a projected opening area Sof the opening to the projected first straight portion area Sis not less than 1.2; and the transition portion is in the form of a taper portion.