Patent ID: 8203258
Filing Date: 2012-06-19
Classification: H01T

Abstract:
1. A spark plug comprising: a rod-like center electrode extending in a direction of an axis; an approximately cylindrical tubular insulator provided on the periphery of the center electrode; a tubular metallic shell provided on the periphery of the insulator; and a main ground electrode and at least two auxiliary ground electrodes having respective proximal end portions joined to a front end portion of the metallic shell, the spark plug being characterized in that the main ground electrode is disposed so that its distal end portion faces a side surface of a front end portion of the center electrode and forms a main spark discharge gap between the distal end portion and the front end portion of the center electrode; each of the auxiliary ground electrodes is disposed so that a portion of its distal end portion end surface faces an outer circumferential surface of a front end portion of the insulator; and a total area S (mm