| 摘要 |
PURPOSE:To detect only components of water pressure pulsation with a high precision, by making a metallic diaphragm, which is deformed in accordance with the pressure pulsation of cooling water, thin in a part, where a pressure sensor is stuck, to increase this deformation of the diaphragm. CONSTITUTION:A pressure sensor 9 consisting of partially a piezoelectric material is stuck to the center of the upper face of a diaphragm 8 by a conductive adhesive or the like, and the thickness of a part 8a where the pressure sensor 9 is stuck of the metallic diaphragm 8 is smaller than that of the other parts 8b. Thus, when the metallic diaphragm 8 is deformed in accordance with water pressure pulsation generated in cooling water by knocking of an engine, the whole of the metallic diaphragm is deformed smoothly and greatly to give a high oscillation pressure to the pressure sensor 9, and a stable output signal is obtained. |
