Paul, I read your article in Kitplanes, but I am confused about the
exhaust
valve being the cause of huge losses.

Is it because of the restriction of the valve? Or is it the
metallurgy not
allowing higher operating temperatures?

Your article was a great read by the way, I saw your web site, please
subscribe me!

You were looking @ roots blowers, I would suggest that you look @
Lysholm,
or screw type compressor.

The Roots blower is about 50% efficient, the Lysholm is closer to
85%, lots
less heating.

Mazda used them on their Miller cycle engine in the Millenia.
How is your recovery turbine coming?
Thanks,
Tom Bowman

It is a bit of both. The kinetic energy is what drives the turbine.
In other words the flow of the exhaust gases. If you put any kind
of obstruction in the flow path it will slow the flow. The
secondary effect is the heat lost to the exhaust valve. Anytime you
withdraw
heat from a gas flow in a pipe the volume of the gas and hence the flow
rate will be reduced. Check out my youtube videos on the subject.

http://www.youtube.com/watch?v=qP3U1tAPc
<ttp://www.youtube.com/watch?v=KcqP3U1tAPc">
http://www.youtube.com/watch?v=WbsO0C8x8
<ttp://www.youtube.com/watch?v=bkWbsO0C8x8">
http://www.youtube.com/watch?v=o5jsrYMK4
<ttp://www.youtube.com/watch?v=6Po5jsrYMK4">

I also have a video of a talk I gave at the World Motorsport
symposium in Oxford the UK on the ACRE website.

http://www.rotaryeng.net/Oxford-640-4802.wmv
<ttp://www.rotaryeng.net/Oxford-640-4802.wmv">

It is kind of on back burner until I get my dyno working.

Paul Lamar

Paul,

Great video of the turbo-compound diesel. I'm a little biased
but I bumped the ratings up a little:)
It is hard to tell how the gas flow moves on the blow down turbine.
I am guessing it comes in centrally goes through a diffuser,
then the turbine and exits in the scroll? Opposite of a
typical turbo-charger turbine. Do you have an idea? If
so I think I may have found a useable turbine at Jet Beetle in Taiwan.

Doug in Japan

Here are some pictures you may not have seen.

BTW they have gone the CW R3350 route on that engine upping the
boost and it is
called the DD16. It now has 600 HP up from 450 with I suspect the same
displacement. No figures on the fuel burn so far. Apparently the sky is
the limit much like it was on the R3350. That must make one heck of an
18 wheeler :)

Paul Lamar


-Paul


OK, Looking at the VOLVO engine says it all and answers most design
questions. Best design I have seen yet for our purposes. Conical
inlet helping to direct the gas flows. Ditto conical on the low
pressure side. And into a scroll and out on top in the direction of your
choice. Slick.

Yes the 3350 pretty much depended on the supercharger providing high
boost up high. The blow down turbine returned that power loss and then
some. For the rotary we are limited by how much backpressure it can
endure and still evacuate exhaust gases well.

What is your opinion on the waste gate flows assuming the waste gate
will be on the manifold?

1. Plumb into the inlet housing of the blow down turbine, Disruptive
flow

2. Plumb it in downstream of the blowdown turbine? Loss of
potential energy.

Granted way up high the waste gate might be closed


These guys have done a nice job.


http://jetbeetle.com/ <ttp://jetbeetle.com/">
Jetbeetle custom cast turbine wheels, NGV for you, covering sizes from
55mm, 60mm, 66mm, 70mm, 90mm,130mm,145mm and any sizes in between, you
name it, we build it.

Doug in Japan

I have not given TC waste gates  much thought. First I want to see
some TC hardware working. The torque extracted from the turbine will
limit the turbine RPM unlike a straight turbo charger system.

The rotary is not like a piston engine. It will tolerate
just about any boost level you can manage to give it. Especially
at RPM levels OVER 6000 RPM as that REDUCES the loads on the rotor
bearing. Another reason they can generate enormous amounts of HP.

Paul Lamar