Subject: turbo-compounding
From: Rotary Engine
Date: 8/13/2008, 9:40 AM
To: AAA Put this in the To box


Roteryians,

Since I have been lurking on this list, I have been confused about the
term Turbo-compounding.

It seems that the way that it is used it is synonymous with turbo
charging. Am I mistaken?

It is my understanding that turbo charging uses the energy in the
exhaust stream to turn a turbine which intern turns another turbine
which compresses the air going to the intake manifold.

Turbo compounding is a different animal. This technique was used around
WWII in large, primarily radial engines, in which the exhaust gasses,
like turbo charging, turned a turbine.  Here's where the similarity
ends. This rotational energy of the spinning turbine, through a system
of gears, was then connected to the crankshaft which increased the power
with roughly the same fuel burn. This was a compounding effect, not a
supercharging effect. There was no increase in MP with the
turbo-compounding.

Now turbo-compounding would be possible by re-inserting the rotating
power at the PSRU.

Has anybody done work on this for the rotary??

Rich

It is related to turbo charging but I would not say it was synonymous with turbo
charging. This is almost a correct statement: "It is my understanding that turbo charging uses the energy in the exhaust stream to turn a turbine which in turn turns another xx turbine xx [No. It turns a centrifugal compressor] which compresses the air going to the intake manifold." My corrections are in []

Last statement is correct.

There are several ways of using a turbine to recover the waste energy in the exhaust. The simplest is to use one turbine on a normally aspirated engine
fed by the exhaust. First attached jpg.

A second way is to extract additional HP out of a turbo charger by connecting an output shaft to the turbo charger shaft. Second jpg. Probably this is the most efficient way using a turbo charged engine to start with as there is minimal heat lost in the plumbing. Any reduction in temperature of the exhaust before the turbine results in a reduction of the kinetic energy available to turn the turbine.

However there is too much temperature in a rotary exhaust for comfortable use by a turbine so a thermoelectric device would cool off the exhaust and generate electricity in the bargain.

There are many other ways. One of the most popular is to add a second turbine after the turbo charger. Third jpg.

Read this web site http://www.rotaryeng.net/turbo-compound.html

View these videos.

http://www.youtube.com/watch?v=iy_Jd5kewbM
http://www.youtube.com/watch?v=emLKhfm6MWE
http://www.youtube.com/watch?v=luoUHrX6DeQ


Paul Lamar

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