KNOCKING DETECTION DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a knocking detection device of an internal combustion engine capable of precisely detecting knocking without requiring expensive constitution. SOLUTION: An ionic current signal corresponding to an ionic current generated immediately after generation of an ignition spark is detected by using an ignition plug 12 arranged in a combustion chamber of an internal combustion engine. A BPF 24a of a filter circuit 24 extracts a signal of a knocking frequency band from the ionic current signal. An adder 24b of the filter circuit 24 extracts a signal except for the knocking frequency band by subtracting (removing) the signal of the knocking frequency band (output signal of BPF 24a) from an ionic current signal Sio. A microcomputer 30 detects generation of knocking in accordance with size of the knocking frequency band and size of the signal except for the knocking frequency band.