The air exhaust passage is arranged to exhaust {HEAD ~ gas} from {TAIL ~ the chamber}, both passages respectively having an intake valve and an exhaust valve therein 
from
The air exhaust passage is arranged to exhaust { HEAD ~ gas } from { TAIL ~ the chamber } , both passages respectively having an intake valve and an exhaust valve therein
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH