What about all the heat transferred to the piston cylinder after the engine has been running for a while.
Could the heat from that be used to vaporise water then power and steam piston adjacent to the main engine.
Like the way a nuclear power plant uses water to power a turbine except the water...
Would it be possible to build an engine that runs primarily off a petrol but has a steam engine that captures all the heat lost from the combustion (70%) and applies it towards powering the engine?
Looking for ideas, opinions and attitudes on whether or not it is a practical idea.