A misfire detector generates a misfire detection signal indicative of {HEAD ~ occurrence} of {TAIL ~ misfiring} in the at least one engine cylinder on the basis of a value of the ion current 
A misfire detector generates a misfire detection signal indicative of { HEAD ~ occurrence } of { TAIL ~ misfiring } in the at least one engine cylinder on the basis of a value of the ion current
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH