| 摘要 |
PURPOSE:To enable judgement on knocking to be made with high accuracy by collecting an index value by each cylinder of an internal combustion engine, performing filter processing of the index values, and thereby setting each knock judging reference. CONSTITUTION:An output from a knock sensor 2 is inputted to an A/D converter 4 via a LPF 3, and crank pulses from a crank angle sensor 5 are inputted to a sampling signal generating circuit 7 via an input interface 6, so that a sampling signal is thereby introduced in response to these pulses. The A/D converter 4 outputs the output of the knock sensor 2 to a frequency analizer 8 while being synchronized with the aforesaid signal. The frequency analyzer analyzes spectral power for each frequency based on sampling data within the set period of observation, so that each maximum value of spectral power is set as each index value every cylinder. Meanwhile, a knock judging circuit 9 determines each knock judging reference based on the index values, it compares the aforesaid reference with each index value for this time, and when the aforesaid reference is found to be larger than the corresponding index value, it is judged that knocking has taken place, so that let a control circuit 11 make an ignition lead angle capacity small. |
