Patent ID: 9371806
Filing Date: 2016-06-21
CPC Classification: F02M,F02P,H01T

Claim Text:
1. A spark plug for an internal combustion engine, comprising: a tubular housing; a tubular insulator held inside the housing; a center electrode held inside the insulator such that a distal end portion protrudes; a ground electrode including a standing portion that stands distalward from a distal end of the housing and an opposing portion that is bent radially inward from the standing portion and opposes the center electrode in an axial direction of the spark plug through a spark discharge gap formed between it and the center electrode; and a guide member for guiding a flow of an air-fuel mixture in a combustion chamber of an internal combustion engine to the spark discharge gap, the guide member protruding distalward from the distal end of the housing at a different circumferential position from the ground electrode and having a guide surface that faces the standing portion of the ground electrode, wherein the opposing portion of the ground electrode has an opposing surface that opposes the center electrode, a back surface on the opposite axial side to the opposing surface, and a pair of side surfaces that connect the opposing surface and the back surface, and of the pair of side surfaces, at least the side surface on the guide member side is formed so as to make an obtuse angle with the opposing surface.