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