The additive can be introduced into a combustion chamber as {TAIL ~ part} of {HEAD ~ the fuel} 
The additive can be introduced into a combustion chamber as { TAIL ~ part } of { HEAD ~ the fuel }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD