{HEAD ~ The auxiliary piston} may function as {TAIL ~ a compression and ignition means} by moving rapidly toward its top dead center position only when the working piston is close to its top dead center position 
{ HEAD ~ The auxiliary piston } may function as { TAIL ~ a compression and ignition means } by moving rapidly toward its top dead center position only when the working piston is close to its top dead center position
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH