| 摘要 |
PURPOSE:To attain to enhance fuel consumption and power capacity by calculating an optimum ignition period with good accuracy, by enhancing knocking detection accuracy. CONSTITUTION:The output of a knocking sensor 10 is directly inputted to a digital filter 32 where multiplexing processing is applied to the output of said knocking sensor 10 and the signal obtained by delaying said output by a predetermined time T to perform the detection of a higher harmonic component. Then, the fundamental wave of the resonance frequency of knocking extracted by a first stage digital filter 32 and the higher harmonic component are further passed through second and third stage digital filters 34, 36 to be amplified and extracted at an extremely high S/N ratio. The output of a final stage digital filter 36 is inputted to a knocking discrimination circuit 38 and the presence or absence of knocking is judged. As mentioned above, by employing the digital filters 32, 34, 36, even a small knocking signal can be extracted in a state separated from noise. |
