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/
<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
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