Temperature and pressure detecting type spark plug

摘要

A temperature and pressure detecting type spark plug has a metallic shell having a mounting seat around an outer surface of the shell. The plug further has a center electrode which is placed into a tubular insulator. The center electrode has a hollow portion to enclose a thermocouple to detect a temperature of the front end of the center electrode. An annular pressure sensor is placed at the mounting seat of the metallic shell to detect a pressure within a combustion chamber in a cylinder head. The pressure sensor is arranged to be sandwiched between the mounting seat and the cylinder head when the spark plug is secured to the cylinder head of an internal combustion engine.