Patent ID: 9160148
Filing Date: 2015-10-13
Classification: G01R,H01T

Abstract:
1. A method for manufacturing a spark plug comprising: a preparation step of preparing a specimen including a bar-shaped center electrode, an insulator disposed on an outer periphery of the center electrode, a metal shell disposed on an outer periphery of the insulator, and a ground electrode with one end attached to the metal shell for forming a spark gap with the center electrode; and an inspection step of determining whether dielectric breakdown is caused in the insulator by applying a predetermined voltage between the ground electrode and the center electrode of the prepared specimen, wherein the inspection step includes; a calculation step of receiving an oscillating wave generated from the specimen upon application of the predetermined voltage to the specimen, determining a power spectrum by subjecting an oscillating wave signal representing the oscillating wave to fast Fourier transform, and then calculating an integral of a predetermined frequency range in the power spectrum, and a judgment step of judging whether discharge is caused by dielectric breakdown of the insulator by utilizing the integral.