| 摘要 |
PURPOSE:To prevent mistaking of noises for knocking vibration, by interrupting detection of vibration for a predetermined while including the time instants when current supply to an injection valve is started and stopped and the time instant when current supply to an ignition coil is stopped. CONSTITUTION:When an engine 10 reaches the starting point of a knocking predicted angle of rotation, an MPU calculates an injection stopping time Tr of each injection valve 14 from the actual time and injection period r and also calculates the time instant T1 for stopping detection of knocking by subtracting 1msec from the time Tr and closing the input gate of a peak-hold circuit of a buffer 150. At the same time, the MPU calculates the time instant T2 for opening the input gate again by adding 2msec to the time Tr and sets the time T1 in a comparation register. When counting of T1 is terminated, the MPU produces a second control signal and the peak-hold circuit of the buffer 150 closes its input gate, and stops production of output signals. After completion of fuel injection, the time T2 is set and the MPU produces a second control signal when counting is terminated. In response thereto, the input gate of the peak-hold circuit is opened again and detection of vibration is recommended. |
