Knock control apparatus for internal combustion engine

摘要

A knock control apparatus for an internal combustion engine includes a knock detector for extracting a vibration component superposed on an ion current, and waveform shaping it at a predetermined threshold value to generate a train of knock pulses (Kp) of which the number of pulses indicates a knock intensity of a knock generated in the internal combustion engine, and an engine control unit for counting the number of knock pulses (npn) in the knock pulse train (Kp) output from the knock detector. The engine control unit judges, based on the number of knock pulses (npn), whether or not a knock is occurring. The engine control unit performs a peak hold of the number of knock pulses to calculate the knock judgement threshold value (BGL) by multiplying the number of pulses by (alpha). Thus, precision in knock judgement is improved by performing knock judgement based on a maximum value (MAX) of the number of knock pulses (npn).