Paul is the RX8 happy to be turbocharged? Should and can the
compression be reduced easily. Could the rotor have a little of the
convex shape shaved off to reduce compression? Or the bowl enlarged?
Mark Dillner
If you put Ianetti ceramic apex seals in it you don't need to reduce
the compression ratio. The stock apex iron seals can run up to 500
F at their center. That can go much higher when boosted and may fail
the seal. The ceramic seals will go to 1000 F.
The same material is used in ball bearings that are good to 1000 F
while steel ball bearings have a 500 F limit. Most ball bearings in
F1 race cars are ceramic.
In that case we have seen 85 inches of Mercury manifold pressure so
far with no damage. Something like 700 HP. The Wankel is amazing!
Paul Lamar
An air cycle turbo expander. Cool idea made into hardware; English,
not American. Murry Rozansky
"A turboexpander, also referred to as a turbo-expander or an
expansion turbine, is a centrifugal or axial flow turbine through
which a high pressure gas is expanded to produce work that is often
used to drive a compressor "
Are you suggesting this be used to cool the apex seal?
Paul Lamar
It is a more effective way to charge cool a high boosted engine and
would reduce internal temps while allowing higher boost. It is a
turbocharger intercooler, if you will. They claim outlet temps below
ambient. For short duration, water injection is simpler.
https://www.aircycletechnology.co.uk/
I forgot link? Murry Rozansky
Where does the HP come from to compress the air? In other words what
is the BSFC?
Paul Lamar
The turbine of the charge cooler runs off of excess boost on the
inlet side of the engine. Instead of wasting exhaust energy of the
engine with an exhaust wastegate after the intercooler on the
compressor of the turbo the air is compressed more in the turbo
compressor then goes through another charge cooler then to the
turbine of the turbo cooler where it expands more and drops further
in temp before going to the engine. It is an aircycle cooling unit
like used on jets for AC running on bleed air. There is a graphic on
the web site. Click on box at bottom of home page. I do not think it
would effect BSFC much directly but would allow downsizing and/or
down speeding for a particular output and it runs off energy that
would go out the tailpipe. More energy would be in the exhaust for
turbocompounding because of the higher boost level..
Murry Rozansky
For the new people charge cooling refers to how the rotor and the
rotor bearings are cooled. The mixture is passed through the rotor
first to cool it and then into the compression chamber. The mixture
is heated so less mass of air and fuel makes its way into the
engine.
This drastically affects the volumetric efficiency because of the
aerodynamic considerations and therefor reduces the HP generated for
a given engine displacement.
The bottom line is the BSFC. The pounds of fuel burned per HP
generated.
What is it?
The ceramic apex seal reduces or eliminates the need to cool it. Are
they running ceramic apex seals?
The oil cooled rotor reduces the temperature of the apex seal slot.
That is part of the apex seal cooling.
Here is some data on apex seal cooling.
Paul Lamar
My take on the dissertation is that air bleed like used on turbine
engines is used to control boost pressure. One problem I can see with
that is possible overspeed of the turbine which could have
catastrophic results. Using a wastegate and putting that back into
the exhaust going through an axial flow power recovery turbine makes
more sense to me.
Dale Davies
Hi, it is a turbocharged intercooler system for conventional
turbocharged engines. It is not intended for rotary charge cooling
but might be useful for that. The turbocoolers turbine is powered by
boosted intake air which drops in pressure and temperature going
through it. They claim sub ambient temp air to the intake manifold.
Murry Rozansky
Do you have any links on this Murry?
Paul Lamar
https://www.aircycletechnology.co.uk/
Murry Rozansky
When P-ported Paul, what do you seal the side ports off with?
Mark Dillner
Red RTV. Good to 500 F. Stuff you buy in the hardware store. Red
silicon rubber cures when exposed to air. RTV stands for Room
Temperature Vulcanizing, Very tuff stuff :-)
We use it to absorb the torsional vibrations from the rotary.
Paul Lamar
To seal side-ports, I used Devcon Plastic, Steel Epoxy Putty 1 Pound 10110
https://www.amazon.com/gp/product/B00065TMTO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
Matt Boiteau
Here is a movie about silicon rubber.
Paul Lamar
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