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:
Feb. 22, 2005
Filed:
Oct. 18, 2002
Gakuji Moriya, Wako, JP;
Kenichi Ishida, Wako, JP;
Kazuyuki Kubo, Wako, JP;
Toshihiro Ohkama, Wako, JP;
Gakuji Moriya, Wako, JP;
Kenichi Ishida, Wako, JP;
Kazuyuki Kubo, Wako, JP;
Toshihiro Ohkama, Wako, JP;
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
A spark plug for internal combustion engine, which produces a spark discharge that ignites air-fuel mixture in the combustion chamber and causes combustion such that an ionic current flow during combustion can be utilized for detecting misfire of the engine. The spark plug the core connected to an ignition coil, a center electrode made of at least one of iridium and an iridium alloy and connected to the core through a seat, and a ground electrode separated from the center electrode with a gap. A sum of surface areas of the seat and the center electrode is not less than a prescribed value, specifically, is not less than 11.0 mm, and more specifically, is not less than 11.47 mm. Even when the diameter of the center electrode is reduced in the interest of improving ignition performance, improved ignition performance and improved ionic current detection accuracy can be achieved simultaneously.