| 摘要 |
PROBLEM TO BE SOLVED: To easily inspect the defect of a spark plug while being attached to the engine body.SOLUTION: A cylinder 12, provided with an excitation coil 14 and an annular permanent magnet 16 from the terminal 6 side, is applied so as to cover the outer periphery of the insulator 5 of a spark plug 4 attached to the spark plug insertion hole 2a of a cylinder head 2, and the spark plug 4 is vibrated electromagnetically by supplying an excitation current Ie to the excitation coil 14. Resonance frequency Vr of the spark plug 4 to which vibration is given is then detected by means of an AE sensor 30, and a determination is made whether or not the insulator 5 has a defect on the basis of the resonance frequency Vr thus detected. |
