公开(公告)号：US09929542B2

公开(公告)日：2018-03-27

申请号：US15472673

申请日：2017-03-29

Applicant: DENSO CORPORATION

Inventor： Kenichi Araya ,  Koji Yamanaka ,  Ken Hanashi

IPC: H01T13/20 ,  H01T13/39 ,  H01T13/32 ,  H01T21/02

CPC classification number: H01T13/39 ,  H01T13/32 ,  H01T21/02

Abstract: A spark plug has an elongated center electrode, ground electrode, convex part and noble metal coating layer. The center electrode is held in a housing. The ground electrode has a tip end opposing part opposing the center electrode. The convex part is extended from the tip end opposing part to an opposing part face in an axial direction of the spark plug. A spark discharge gap is formed between a tip end part of the center electrode and the convex part. The noble metal coating layer covers a surface of the convex part. The noble metal coating layer has an end face coating layer covering a projecting end face of the convex part and a side face coating layer covering at least a part of a side face of the convex part extended from the projecting end face. A root part of the side face coating layer is buried in the tip end opposing part. An extension is formed so that at least a part of the root part is extended to an outside of the spark plug along the opposing part face.