ancient greece automaton automobile base circle bourke engine britalus rotary engine camshaft connecting rod controlled combustion engine crankshaft cylinder head porting d slide valve dwell cam flat engine free-piston engine gas turbine h engine heat engine jet engine lever multi-valve napier deltic one-stroke cycle opposed piston engine orbital engine peaucellier-lipkin linkage piston piston valve pistonless rotary engine poppet valve quasiturbine radial engine radius rocket engine rocket engine nozzle rotary engine screw machine single cylinder engine six stroke engine sleeve valve steam engine steam hammer stelzer engine stirling engine straight engine swashplate swing-piston engine thermodynamic cycle trip hammer twingle engine v engine valve w engine wankel engine wheel