| 摘要 |
PURPOSE:To reduce variance in the electric damping characteristics of a knocking sensor by incorporating a resistance in the knocking sensor and adjusting the electric damping characteristics of the knocking sensor through only the knocking sensor itself. CONSTITUTION:A discoid type metallic diaphragm 5 is welded to the center part of the substrate 4 in a metallic case 1 and a piezoelectric element 6 is stuck; and its upper end surface is connected to an engine earth through the diaphragm 5, substrate 4, and case 1, and the lower end surface of the element 6 is connected to a knocking detecting circuit 16 from a lead terminal 7 and a terminal 3 through a signal line 14. A resistance 8 for connecting the terminal 3 and substrate 4 together is provided at the center part of the substrate 4 to form the knocking sensor 13, and the load resistance 8 is adjusted according to manufacture variance in the electrostatic capacity of the piezoelectric element 6 to obtain the knocking sensor which has small variance in electric damping characteristics. |
