The Carnot cycle is composed of four steps: isothermal expansion, adiabatic expansion, isothermal compression and adiabatic compression.
In the case of combustion engines, we have the idealized Otto cycle and the actual Otto engine. At least for pedagogical purposes, it would be very nice to see an actual Carnot engine which tries to approximately implement the Carnot cycle.
So are there such technical realizations?
(Note that I'm not asking for a truly reversible engine nor whether a Carnot engine would be useful in practise.)