Piezoelectric fluid pressure sensor.

摘要

A piezoelectric sensor for an internal combustion engine having a hollow main body (1) is adapted to be mounted on a cylinder head of the engine. The hollow main body is provided with a metal diaphragm (6) tightly fixed to the open one end thereof for receiving a pressure generated within the cylinder, and contains a detector means which comprises a piezoelectric element (11) of LiNbo3 single crystal piezoelectric material for generating an electrical signal corresponding to the pressure in the cylinder, a member (7) for transmitting the pressure from the diaphragm (6) to the piezoelectric element (11) and pressurising means (15) for applying a pressure of 5 MPa or more to the piezoelectric element (11).