Do you have the Mazda tech paper on the hydrogen powered rotary.
Japan SAE C389/233 US SAE 925011 I think.
"Hydrogen fuelled rotaty engine. T Teramoto, Y Takamori, & K Morimoto.
Paul Lamar
Doug, here are a few graphs from that hydrogen tech paper I mentioned.
Note how the efficiency gets better as the mixture gets leaner.
Tracy Crook discovered the same thing burning gasoline.
Mazda is struggling here for a few percent improvement in the efficiency.
In the mean time half the energy in a pound of fuel is going out
the exhaust as waste heat. Typical for all IC engines. Besides turbo
compounding there are other avenues to be explored. A thermal pile
converting
the waste heat directly to electricity to charge a hybrid battery is
one possibility. Another is; generate steam for a small steam turbine.
Commonly done with gas turbines in stationary power plants
yielding over 50% overall efficiency.
Paul Lamar
Yes I am aware of the drawbacks in using hydrogen in an ICU engine. Mazda is
as well of course. They are chasing after performance where they can find
it. Some of the research methods in this part of the world would drive the
typical American researcher crazy though. Endless and meticulous. They leave
no paths (even obviously impossible ones) unexplored. And then they do it
all over again.
A small thermal pile downstream of the turbo is a good way to pick up
enough energy to charge the battery. Good cost performance idea for a
back-up alternator. Why didn't I think of that? :) Energy Conversion
Devices Inc. in Michigan did a lot of the initial work on these devices
about 25 years ago. They are selling different sizes now. Perhaps through
Uni Solar Inc. They work best with a high temperature differential. Great
for airplanes at altitude. Too bulky and pricy in sizes needed to produce the
8 hp boost we are looking for.
Since we are discussing nukes, hydrogen, zinc cans and 'what ifs' on this
thought stream, did you have a chance to look at the Bowman website address
I sent awhile back?
http://www.bowmanpower.co.uk/turbo_alternators.html
At present they manufacture high speed turbo-electric generators over 25 kW
but the concept looks possible for a hybrid rotary. The turbine drives a
high speed generator supplying energy to a electric motor (about 80mm thick)
that replaces the flywheel and acts as the starter motor as well. Most of
this technology has been driving around the road for a 5 years now.
For an airplane the present bottle neck would be the weight disadvantages.
Sure we could carry less fuel but.....
The alternator and flywheel elimination is weight traded for the electric
motor but the generator even a 7kW unit combined with a small buffer
battery, and controller weight is added. Ah well. Perhaps someday....
At this point in time, Paul's turbo compound idea connected to the flywheel
through some sort of clutch (ferro fluid?) has the best weight, and
simplicity of installation.
Doug in Japan.
BTW Doug these variable vane turbo charger are very popular in Europe right
at the moment and they should broaden the band over which the turbo compound
will work. Say from 2500 RPM to 4500 RPM. Here are some pictures I took
at the Geneva auto show this spring.
Paul Lamar
Nice piece of engineering. I imagine the ring on the bottom rotates a few
degrees and moves the vanes correct?. Quite thick casting. What metal is
it?
Doug in Japan
You have me there Doug. I have no details. Perhaps Garret or some other turbo
manufacturer has more details on their web sites. These have now become
de rigor(s?) on all European diesels including the Mazda diesel.
Amazing what a huge tax break on diesel fuel can do :)
Paul Lamar
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