Editing Reciprocating engine (section)

==Other modern non-internal combustion types==
Reciprocating engines that are powered by compressed air, steam or other hot gases are still used in some applications such as to drive many modern torpedoes or as pollution-free motive power. Most steam-driven applications use [[steam turbine]]s, which are more efficient than piston engines.

The French-designed FlowAIR vehicles use compressed air stored in a cylinder to drive a reciprocating engine in a local-pollution-free urban vehicle.<ref>[http://zeropollutionmotors.us/ AIRPod] manufactured by MDI SA. Accessed February 19, 2015</ref>

Torpedoes may use a working gas produced by [[high test peroxide]] or [[Otto fuel II]], which pressurize without combustion. The {{convert|230|kg|lb|abbr=on}} [[Mark 46 torpedo]], for example, can travel {{convert|11|km|mi|abbr=on}} underwater at {{convert|74|km/h|mph|abbr=on}} fuelled by Otto fuel without [[oxidant]].