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A gasoline generator with a 97% efficiency rating.

A gasoline generator with a 97% efficiency rating. - Physics Forum

A gasoline generator with a 97% efficiency rating. - Physics Forum. Discuss and ask physics questions, kinematics and other physics problems.


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  #1  
Old 03-05-2004, 04:25 PM
Laurent
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Default A gasoline generator with a 97% efficiency rating.



DOE is considering a grant request for a gasoline generator
prototype which could operate at about 97% efficiency. Currently the
best they can do is about 65%, the rest is lost as heat.

It's really very simple and low tech. It is basically an airplane
gasoline motor fitted with a sliding-vane turbine on the intake,
which would take advantage of the air flow created by sea level
atmospheric pressure. Since this would be an airplane engine whose
performance is supposed to peak at high altitudes, or at low
atmospheric pressures (airplane engine manufacturers do this by
simply using a specially grinded camshaft), and since my generator
is supposed to work at sea level, at standard atmospheric pressure,
the air flow restriction caused by the intake turbine would work to
its advantage. The extra power would come from a generator attached
to the intake sliding-vane turbine.

--
Laurent


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  #2  
Old 03-05-2004, 05:51 PM
Ian Stirling
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Default A gasoline generator with a 97% efficiency rating.

In sci.physics Laurent <[Only registered users see links. ]> wrote:

The requestor should be interned in guantanamo bay.

You can't get 97% from an internal combustion engine on earth
for basic thermodynamic reasons.
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  #3  
Old 03-05-2004, 05:57 PM
QDurham
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Default A gasoline generator with a 97% efficiency rating.

>The requestor should be interned in guantanamo bay.

Or the local loonie bin.

Quent
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  #4  
Old 03-05-2004, 05:59 PM
Opus Penguin
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Default A gasoline generator with a 97% efficiency rating.

Ian Stirling wrote:

Heat loss is the biggest issue, no? Could they line the cylinder walls,
piston top, and valves with some sort of bakelite to keep the heat in the
chamber? That would help, wouldn't it? Also, don't they lose energy in
unspent gasses? Can't they put in 3 or 4 spark plugs per cylinder to make
sure they burn every last drop of fuel mixture?

--
____________________________
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  #5  
Old 03-05-2004, 06:18 PM
EjP
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Default A gasoline generator with a 97% efficiency rating.

Opus Penguin wrote:

I think he was referring to the maximum efficiency out of any engine,
which is (Thot-Tcold)/Thot. If you take the cold bath to be the
typical environment - about 300K - then you would need an operating
temperature of at least 10,000K to get 97% efficiency, even if you
could somehow get a perfect Carnot cycle. I think the typical
combustion energy of gasoline is around 2000K, so this sounds like
a stretch.

-E

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  #6  
Old 03-05-2004, 06:35 PM
Gregory L. Hansen
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Default A gasoline generator with a 97% efficiency rating.

In article <9e32c.55898$[Only registered users see links. ].prodigy.com> ,
Opus Penguin <OpusPenguin@BloomCounty.nospam> wrote:

The Carnot efficiency of a heat engine is (T_hot - T_cold)/T_hot. That's
a theoretical maximum efficiency. You could line cylinder walls,
recirculate and reheat, add spark plugs, put turbines in the exhaust, and
anything else you want, and you won't beat Carnot.

An engine that reaches 97% of Carnot efficiency would at least be
believable.

--
"The average person, during a single day, deposits in his or her underwear
an amount of fecal bacteria equal to the weight of a quarter of a peanut."
-- Dr. Robert Buckman, Human Wildlife, p119.
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  #7  
Old 03-05-2004, 07:07 PM
Greg Neill
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Default A gasoline generator with a 97% efficiency rating.

"Opus Penguin" <OpusPenguin@BloomCounty.nospam> wrote in message
news:9e32c.55898$[Only registered users see links. ].prodigy. com...
walls,
in

You dump and lose hot gases with every exhaust stroke,
regardless of how thoroughly combustion went. The
heat in the exhaust represents energy lost.


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  #8  
Old 03-05-2004, 07:25 PM
Steve Ralph
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Default A gasoline generator with a 97% efficiency rating.


"Greg Neill" <[Only registered users see links. ]> wrote in message
news:Td42c.100805$[Only registered users see links. ] ...
the
energy
make

Rolls Royce are adressing converting this lost heat to power

[Only registered users see links. ]

Which if it works would increase the efficiency of the total system

SR


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  #9  
Old 03-05-2004, 07:38 PM
Uncle Al
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Default A gasoline generator with a 97% efficiency rating.

Laurent wrote:

Hey stooopid - Second Law vs. source and sink temps for a heat
engine. You are a liar, an imbecile, or a crook. Do not think of
each category as being exclusive of the others.

--
Uncle Al
[Only registered users see links. ]
[Only registered users see links. ]
(Do something naughty to physics)
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  #10  
Old 03-05-2004, 07:55 PM
tadchem
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Default A gasoline generator with a 97% efficiency rating.


"EjP" <[Only registered users see links. ].bad> wrote in message
news:c2ag5t$r0v$[Only registered users see links. ].gov...

<snip>


Correct.

To this I would like to add that Edison, in his search for filaments for his
incandescent lamp, needed to find a material that could maintain structural
integrity (i.e. it would not melt) at the highest temperature possible -
because emissivity (brightness) increases rapidly with temperature (to the
fourth power as I recall) and spectral characteristics of light are ideal
for humans at 6000K.

The best he could do was with tungsten, which melts at about 3683K.

This would limit the efficiency of a real-world internal combustion engine
to a little over 92%.

Each percentage point gain in efficiency costs more than the previous one.


Tom Davidson
Richmond, VA


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