A source of {TAIL ~ fugitive gases} is directed to the air intake of {HEAD ~ the engine} 
A source of { TAIL ~ fugitive gases } is directed to the air intake of { HEAD ~ the engine }
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD