Attachment structure of glow plug with combustion pressure sensor and glow plug with combustion pressure sensor

An attachment structure of a glow plug with a combustion pressure sensor, in which the glow plug with the combustion pressure sensor is configured to be attached to an internal combustion engine,

• wherein:
• the internal combustion engine comprises a combustion chamber and a plug hole communicating with the combustion chamber,
• the plug hole has an inner wall surface, and the inner wall surface of the plug hole is formed with an internal thread portion and a seat portion located closer to the combustion chamber than the internal thread portion thereto, the seat portion protruding inward of the plug hole,
• the seat portion has a taper seat surface inclined to inwardly taper toward the combustion chamber,
• the glow plug with the combustion pressure sensor comprises:
• a cylindrical housing that is fixable to the plug hole;
• a glow heater that is held in the housing and protrudes toward the combustion chamber;
• a load transfer member that is disposed inside the housing and transfers compression strain as a pressure, the compression strain being generated in the housing due to generation of a combustion pressure in the combustion chamber;
• and
• a pressure detector that detects the pressure received from the load transfer member,
• the housing comprises:
• an external thread portion screwed to the internal thread portion of the plug hole;
• and a seat facing portion formed on a tip side of the housing relative to the external thread and facing the seat portion of the plug hole in an axial direction,
• the seat facing portion has a tapered contact surface in surface contact with the tapered seat surface, and
• a recessed portion is formed in a radial portion of at least one of the seat facing portion and the seat portion, and is axially recessed to be in non-contact with the seat portion or the seat facing portion, and is formed annularly about a central axis of the housing.