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The internal combustion engine in a car may be fitted with a
turbocharger. This is a relatively simple device in concept: the
exhaust gasses power the rotation of a turbine, this turbine is
linked to a compressor which forces air into the engine at above
the ambient pressure. This can make a
small engine have the
output of a much larger one. The role of the internal
combustion engine in this scenario is to simply provide the
conditions for combustion and to extract the energy in
mechanical form.
A simplification of this concept is the jet engine, no chains,
cranks cams etc. Just compressor, fire, turbine. Turbine powers
compressor, compressor feeds fire, fire powers turbine on and
on until you run out of fuel or materials science.
Why not turbocharge the humble camp stove? I propose
something similar to the rocket-mass heaters <link>. Place the
turbine on the chimney, run the compressor into the air inlet
and seal everything up tight inbetweeen adding fuel. We can
include an intercooler (providing heat for the tent etc.) and
other features like a manual blow-off valve to prevent runaway
boost blowing the whole thing up.
The turbine will of course get quickly gummed up with wood
combustion products like creosotes, but this isn't a problem in
the enthusiast market. The target market is largely
Scandinavian motorsport fans who seem to enjoy wood, alcohol,
fires, turbochargers and alcohol, so they can drink beer while
tending the turbo stove waiting for the next sideways car to
slide into their nearest ditch.
Rocket Mass Heater
https://en.wikipedi.../Rocket_mass_heater
[bs0u0155, Dec 20 2021]
BioLite Stove 2
https://www.biolite...ts/campstove-2-plus
Fire powers the fan, which helps the fire, and extra juice goes to a USB charger [sophocles, Dec 21 2021]
It turns out this works extraordinarily well
https://www.youtube...watch?v=ByuCdCo9-XI
[bs0u0155, Apr 06 2023]
[link]
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it seems your link has combusted itself!? |
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You can actually get something quiet similar today (see the
Biolite link.) |
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The fire provides energy that's captured by a thermoelectric
device, that then powers an electric fan. Excess energy
trickles to a USB port which can charge phones. |
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I got a BioLite stove >5 years ago, and it still works, still
creates a hot little fire from a few sticks, burns quite clean
(very little ash or smoke) and charges a phone (slowly). |
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Your wood would burn up more quickly, instead of lasting
longer. You might get more heat, but at the cost of longevity. |
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Add a generator to the shaft to extract power: kind of like a
gas turbine generator, but wood powered. |
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Power take off from turbochargers does exist. They
currently do it in F1, but it's fiendishly difficult... which is
why they're dropping it from F1. Turbos spin VERY fast and
operate at extreme temperatures. I suspect the way to go
would be to have magnetic tips on the intake compressor
wheel and have generator coils on the housing. Hopefully
you can use the intake air to keep the temps below the
Curie limit. |
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When I was at Ricardo we would get all sorts of half-baked
engine inventions thrown at us from various sources. I recall
one proposal that wanted to use the turbos to turn the
accessory drive. We never pursued it due to reasons of
practical physics. |
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//I recall one proposal that wanted to use the turbos to
turn the accessory drive. We never pursued it due to
reasons of practical physics.// |
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I mean, if you go the full F1 route, you can get a lot of
function out of putting a generator on the turbo shaft. You
can use excess exhaust energy to generate electrical power.
If you're in the business of doing that, you may as well
make the generator a BLDC motor, and then you can spin up
the turbo. But if it's being dropped from F1, then that
means it is staggeringly expensive/difficult or useless. |
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I'll bet it's related to the RPM & temperature. You can't spin
at turbo speeds without significant eddy current losses
(&heat), so you gear it, and get gearing losses (&heat), or
you make a large, low RPM turbo and get losses there (&
heat, probably). Then you have to try and keep the
motor/generator cool a few mm from an exhaust manifold. |
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In a car it makes less sense, super expensive and it doesn't
work at low RPM. It may be workable in aviation, but
probably not, because they don't like new things. The best
application is likely long-distance trucks - lots of constant
RPM work, fuel cost a real factor. |
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All this is predicated on turbos extracting "free" energy,
which was received wisdom even among the educated for
years. Absolutely not true of course. The only thing you get
"free" with a turbo is the fact that it acts as a partial
muffler for both the intake and exhaust. |
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If you want more efficiency out of the accessory drive,
probably a good idea to manipulate the alternator field
strength based on engine load - do your generating on
braking/overrun and during the more efficient parts of the
engines BMFC map. Complex, but it's mostly just code & a
new output for the ECU. |
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Now accomplished by the perhaps inevitably Australian, "Bobby McBoost" <link> |
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