{TAIL ~ Structure borne sound sensors} or ion current sensors may also be used to detect {HEAD ~ a variable} characterizing the combustion in a combustion chamber 
{ TAIL ~ Structure borne sound sensors } or ion current sensors may also be used to detect { HEAD ~ a variable } characterizing the combustion in a combustion chamber
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH