Truck diesel engines are already "blowdown" type turbochargers, they don't use superchargers driven by the crankshaft as this wiki article suggests.
Apparently this "compound turbocharged engine" is just a method of using several turbochargers to increase pressures without increasing intake air/fuel flow.
Trucks with a single turbocharger are already running boost as high as 30 lbs, and when pulling a heavy load up steep roads engines are getting pretty hot as it is. Adding more boost will only make those combustion chambers and exhaust gases leaner and hotter.
That's probably the reason why Detroit diesel never got past the development stage with them.
I am not understanding why nobody understands what this is.
Read this:
http://en.wikipedia.org/wiki/Turbo-compound_engine
The compound turbo DOES NOT ADD BOOST TO THE INTAKE! There is no compressor side to the turbo. The turbo shaft is connected directly to the drivetrain. The turbo is DIRECTLY DRIVING YOUR DRIVE WHEELS!
It’s not charging the intake.
Huh? Detroit Diesel engines have a LONG history of using "roots" superchargers, in fact the 4/71 and 6/71 "roots blowers" (which later made their way to hot rods and drag racers) were standard on Detroit Diesels (the 8/71 and larger were aftermarket, rather than GMC manufactured.)
Take another look at the design. The "compound turbocharger" is NOT used to increase the intake charge density. What's happening here that the exhaust gasses from a 2 stroke engine power a turbine whos output shaft is coupled to the engine's output shaft, thereby using some of the wasted power from the exhaust gasses and using that to augment the output of the 2 stroke engine.
Regarding the compound turnbsharger, this has nothing to do with the intake side.
Mark