| 摘要 |
PURPOSE:To enable to prevent knocking properly by a method wherein a time constant is given to an output from a gain control circuit in an ignition timing control system for an internal-combustion engine utilizing knocking feedback. CONSTITUTION:A variable gain amplifying circuit 205 is provided at the output side of a BPF (band pass filter) 204 and the integral time constant is given to the output of the gain control circuit 206. According to this constitution, a big level difference between a knock signal and a non-knock signal is generated in the BPF204 and the big level difference is inputted into the variable gain amplifying circuit 205 as it is. The signal and a BGL (back ground level) can be changed with the same speed even if there is a sudden change in the BGL, therefore, an S/N ratio may be improved. According to this method, knocking may be prevented properly. |
