PURPOSE: To improve the corrosion resistance of a sensor by inserting a guide member combining a pressure sensor into the inserting hole of an ignition plug and by fitting the sealing member adhering to a plug boot and the boss part of the ignition plug inserting hole.
CONSTITUTION: A guide member 30 is fitted to the outer periphery of a pressure sensor 15 and is inserted into the ignition plug inserting hole 31 forming on a cylinder head 10 and is screwed into an ignition plug screwing hole 11 by an ignition plug 12. A cylindrical sealing member 36 is also fitted on the upper part outer periphery and the sealing member 36 is adhered closely to a boss part 42 on the total periphery by the flange part 41 forming on a plug boot 40, further, the lead line 21 which is from the pressure sensor 15 is fitted to a protective tube 43 and is made to be taken out to the outer part with air-tightness from the port 45 of a lead wire. The invasion of rain water and oil, etc. from the outer part can be thus prevented surely and the corrosion resistance of the pressure sensor 15 can be elevated remarkably.
NAGAISHI HATSUO
TAKEUCHI KIYOSHI
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