Allision V1710E22 Turbo Compound technology / XP-63H

[DaveB.inVa]

The only real useful engine that used turbocompounding was the R-3350. It faired pretty well in airline service using turbocompounding. The only other engine I can think of was the Napier Nomad. It is certainly different than just about any of the arrangements. Think something of a diesel engine sitting on top of a turboprop... complete with an afterburner!

One of the things with turbocompounding is the complexity, weight and size. The R-3350TC had 3 power recovery turbines that were geared down and driven through a fluid coupling then to the crankshaft. In this form on the Lockheed Constellation the engine had a two speed single stage supercharger.

But youve got to remember pretty much everything had an internal supercharger geared to the crankshaft.

I dont know of any engines using both a turbo and being turbocompounded.

However the B-29, B-32 and B-36 used twin turbos in parallel feeding a single stage engine mounted supercharger. With the B-36 you could even cut off one turbo per engine to eliminate surge problems at high altitudes.

 

[syscom3]

I thought the R4360 also used turbo compounding with power recovery.

 

[DaveB.inVa]

Not that I know of. They did attempt using variable discharge turbines. This was not turbocompounding though. It involved a big turbo being mounted so exhaust gasses could be used for propulsion. The variable discharge portion had clamshell doors that could assure the turbo could produce optimum boost all the time and the velocity of the hot exhaust gasses were optimized as well. With this there was no mechanical connection between the turbos and the engine. It also should be noted that turbocompounding = power recovery.

This setup is starting to be common among diesel trucks. Both Fords Powerstroke and Chevys Duramax use variable discharge turbines. Not to provide thrust but so that the exhaust gas flow is always optimized. When you have low exhaust volume the exhaust housing acts as a smaller unit and with large exhaust volume as a large exhaust housing. This means you can have a big turbo and spool it like a small one, yet at higher speeds the exhaust isnt choked and you have the best of both worlds. It also allows for better turbo response. Cummins is currently "supposed" to use a VDT on its new 6.7liter I-6 for Dodge trucks. Im not certain on this as this combination was only released today.

 

[schwarzpanzer]

VDT has been commonly used on diesel cars for a while now, all the GT.. series seem to have it.

 

[Pannoowau]

good posts... thanks for the post....

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