Lots of press has been given to different designs.
Different combinations of opposed piston, turbo compounding and steam co-generation
have flooded the internet.
That was an interesting read, but started out with an untrue statement.
Unburnt fuel rarely escapes a modern internal combustion engine.
"The internal combustion engine (ICE) has had a remarkably successful century and a half. Unfortunately, it’s notoriously inefficient, wasting anywhere from 30 to 99 percent of the energy it produces and
spewing unburned fuel into the air."
True the internal combustion engines today rarely exceed 35% thermal efficiency.
Most average less than 15% in normal transportation service.
The HUGE prime mover engines in ships and diesel power plants manage 50%
at their best RPM.
The only way I have seen that comes close to 75% is various forms of co-generation'such as
gas turbine steam power generation and similar combinations with huge Diesels.
Even then rotary work efficiency is barely 70% and the rest is used as heat or
in a stirling engine (heard of stirling used in this manner, never seen it myself.)
Thanks for the interesting read , but i suspect it to be 90% hyperbole (bullshit).
HH