As the working fluid (and sometimes, fuel) in the (external combustion) naphtha engine.

Because it works by external combustion, the engine could in theory power a pollution-free vehicle and run on almost any fuel.

When external combustion is used, it is possible to use exhaust air from the turbine as the primary combustion air.

A steam engine uses external combustion, as opposed to internal combustion.

One of the downsides of a car powered by external combustion - the heat is outside the engine rather than inside - is that a backfire can occasionally cause a blaze.

Power Plant: Two-speed, reciprocating external combustion; Mono-propellant (Otto fuel II)

His first cycle is very similar to what is now called the "Brayton cycle", with the exception that it uses external combustion.

The difference initially seems insignificant, but external combustion is what gives the calliope its staccatto.

Robert Stirling - Stirling engine (external combustion)

Also other types with external combustion like the Stirling engine or without combustion like the fuel cell are only used in planes.