| 摘要 |
PURPOSE:To detect knocking vibration in excellent sensitivity by setting the resonant frequency of a sensor case close to the resonant frequency of the diaphragm of the sensor and making the bandwidth of resonant characteristics obtained by synthesizing both larger than the bandwidth of the diaphragm. CONSTITUTION:The sensor 1 is formed in such a manner that the diaphragm 3, which resonates with the knock vibration of the specified central frequency of the engine and converts the mechanical vibration into electrical signals, is encased into the case 2 while the shape, size, etc. of the case 2 mounted to an engine proper are selected appropriately and the resonant characteristics are made resonate with the vibration of frequency different from the central frequency of the diaphragm close to the central frequency of the diaphragm 3. Accordingly, even when there is scattering on production in the sensor 1, the knocking vibration can accurately be detected in excellent sensitivity by selecting the resonant frequency of the diaphragm 3 as fP and the resonant frequency of the case 2 as fC and obtaining the resonant characteristics acquired by synthesizing both as frequency G. |
