When {HEAD ~ the level} of the low frequency components is larger than {TAIL ~ a predetermined value}, it is regarded that the noise is generated due to unstable combustion during the low load operation or the spike noise is generated due to corona discharge of a spark plug 16, and the determination of the occurrence of knocking is prevented 
is larger than
When { HEAD ~ the level } of the low frequency components is larger than { TAIL ~ a predetermined value } , it is regarded that the noise is generated due to unstable combustion during the low load operation or the spike noise is generated due to corona discharge of a spark plug 16 , and the determination of the occurrence of knocking is prevented
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH