Paul,

Can you direct me to the article or post on turbo compounding using
electric generator to drive a DC motor connected to the E-shaft method.
While the conversion losses may be higher then that of a direct
drive via speed reduction unit, it would appear that the electric
method would be fairly easy for the home builder to put together.

Thank you
Rick.


Here are a couple of papers from the DOE on the Caterpillar program.

Paul Lamar


Paul,

Thank you for the documents on electric turbo compounding.  Of course my interest
is in Turbo Compounding a 13b.

Given the available exhaust heat/pressure in on a 13BT what size generator
and what size crankshaft motor would you suppose is needed to recover any excess energy?
What would you guess the mechanical/electrical/thermo losses might one
see a rotary setup? (in terms of %)

What sort fuel efficiancy would you guess/estimate can be realisticly
gained from such a setup on a 13BT?  I know that these are all very
vague questions but I'd like to get an idea of the "ballpark" figures.

Do you have any off-the-shelf turbos that would be suitiable to modify
and incorporate into a turbo-compund application?

Overall I can see why you are so passionate about turbo-compounding,
I too ask myself if it such a great thing then why hasn't anyone put
it into wider use? --Although I am guessing that the answer to this
question is more complicated then the technical challege of putting
together a practical Turbo Coumpound system together.

Thank you
Rick.

50 HP recovered is about doable on a two rotor. However an electric solution
means you will throw away about 10 HP of that or 20% not to mention the severe
weight penalty.

I think a 15% improvement in BSFC right off the bat with an all mechanical system
is very doable.

As development progressed we might see as much as a 25% improvement down
the road.  It also depends on the altitude and the duty cycle.
Aircraft engines will see the most benefit.

We just can't go on throwing away 50% of our gasoline out the exhaust
pipe of our internal combustion engines.

The turbo with the most potential is a Borg Warner used on Porsche's
with a variable area nozzle.

Paul Lamar


Paul,

I see your point, The weight penalty of an electric system capable
of transferring 50HP to the crankshaft does seem to be a bit much.

It would appear that a mechanical system would be the best design,
I suppose that the challenge then becomes gearing down from a
turbine speeds down to crankshaft speeds.

I noticed the Wankel-axial turbine concept on your website....
http://www.rotaryeng.net/Turbo-compound2-3D.jpg .  Is this only
a concept or is there someone working on a actual prototype?
Have their been any discussions/posts/web links on this design
that you can direct me to?  What are the pros and cons of the
Wankel/axial turbine design?

Also, in one of your online video's you had made mention of NASA
recovering 80HP out of a Turbo compound Wankel back in 81' or 91'.
What sort of set up did they have?  is there any info available on
their efforts?

Thanks much,

Rick.

As far as I know nobody is working on that concept but it is the
simplest. The trick is to the blades up to 300 or 400 MPH at 7500 RPM.
That is were you get max HP from the  600 or 800 MPH exhaust gas.

Yes. Download this paper.

http://www.rotaryeng.net\NASA-Paper-turbo-compound-rotary.pdf

Paul Lamar