Exhaust-recovery Turbines

[jiffo]

Had a close up look at some Wright Cyclone R3350 aero engines yesterday. Those guys had some ideas.

3-turbines but not coupled to compressors as in our conventional turbos.

They're geared back to the crank, so they use the exhaust gas to directly develop crankshaft power.

The story mentioned they add around another 500hp in the big power configuration.(around 3500hp)

[Sarumatix]

Wow never heard of these

Following the war, in order to better serve the civilian market, the Turbo-Compound[2] system was developed in order to deliver better fuel efficiency and thus economy ("gas mileage"). In these versions of the engine, three power recovery turbines (PRT) were inserted into the exhaust piping of each group of six cylinders and geared to the engine crankshaft by fluid couplings in order to deliver more power (rather than by using the exhaust to deliver additional boost as in a turbocharger). The PRTs recovered about 20 percent of the exhaust energy (around 500 HP) that would have otherwise been wasted, but unfortunately had a negative effect on engine reliability, causing many aircraft mechanics of the day to nickname them "Parts Recovery Turbines" (and worse). The failures concerned would probably have been of exhaust valves and related parts since the turbines would have both increased backpressure & increased the operating temperature of the exhaust valves causing greater wear and failure.[citation needed]

Straight from wiki

[lachlanw]

from back in the days of the napier nomad . google that

john deer actually had an engine that had a turbo exhaust wheel drivinv an electric generator that powered the crank . total effiency was about 47% which is pretty good

[sneakey pete]

its just a turboprop with a 4 stroke inplace of part of the compressor and the ombustion chamber, really. Good idea though, but hell of a maintenance problem it seems.