[27183]

High performance "modern" steam engines are fascinating, they're not necessarily simpler than their internal combustion successors, just different. Monotube boilers create superheated steam that pushes 1200°F, which is right around the same temperature as the exhaust gasses in truck's diesel engine pulling a large hill at maximum power. Hot enough to melt aluminum save for the presence of oil jets to cool the piston and a jacket of cooling water surrounding the cylinder. However, since there's no combustion happening in the cylinder of a steam engine, you don't have any cooling water surrounding it--that would be totally counterproductive. So steam engines operate in a thermal regime that is far more extreme than internal combustion engines. Consequently, bores are often cut slightly tapered to account for the temperature gradient across the stroke, in a double acting engine the cylinder bore has a slight hourglass shape, otherwise the thermal expansion would cause the piston to bind at the ends.

For a fun rabbit hole to dive down, check out Doble steam car technology or the Besler airplane engine.

[glinscott]

Thanks for the pointers! That is an area I've not explored much - reciprocating steam using modern technology. Using modern electronics, sensors and valves to optimize steam expansion would be a fun project. Perfect cutoff every time :).