Derek,
This has been an interesting subject to investigate. As you well know, the
interest in high-mileage carburetors goes back to the infamous Pogue
carburetor that was supposed to get up to 200 mpg. Here's a link to a little
(favorable) history:
http://energy21.freeservers.com/pogue.html
As counterpoint, here's another link that debunks Pogue and similar
"inventions":
http://www.snopes.com/autos/business/magiccar.htm
>From what I've been able to find out, and it was certainly what I expected,
the stories about tanks and airplanes using flash evaporation type
carburetors are simply urban legends. Our airplanes did have an advantage in
WWII, but it was the superior octane aviation gas that was produced in
state-of-the art refineries using newly developed heterogeneous reforming
catalysts that was responsible. The US took a big gamble and it paid off.
I have looked at Kulasinghe's US patent. For those who are interested in the
details, here is a link:
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=/netahtm
l/search-adv.htm&r=1&p=1&f=G&l=50&d=pall&S1=kulasinghe.INZZ.&OS=in/kulasingh
e&RS=IN/kulasinghe
In case this link doesn't work, the patent number is 5,398,663. Getting a
patent is not really much of an endorsement of its efficacy, especially in
the US. Maybe the only place where it's easier to get a patent is in Sri
Lanka. I notice, for example, that the patent does not say what the gas
mileage is in absolute terms, just relative to a "standard bottle of fuel".
Is the 73% improvement from 10 to 17.3 mpg, or from 20 to 34.6 mpg? I have
also not been able to locate any other papers by Kulasinghe published in
generally available journals.
One question to think about is what is the experience of vehicles burning
methane (CNG, LNG, etc.)? Wouldn't this have the same basic efficiency as is
claimed by the basic Pogue carb idea? One study I've seen shows an 8%
improvement over diesel-powered vehicles on a normalized fuel energy content
basis. (http://www.afdc.doe.gov/pdfs/deere6081.pdf) I assume the compression
of this particular methane fueled engine was optimized; i.e., higher than
for a gasoline engine, but less than for the diesel. I pretty sure, if you
just convert a regular compression engine for methane, the gas mileage will
decrease because there is less energy available compared with gasoline, but
people do it for pollution and cost-per-mile, not miles-per-gallon reasons.
It's even harder to believe that converting a small portion of the fuel to
"vapor" as in the Kulasinghe or Pogue devices would have much direct effect.
The thermodynamic model for an internal combustion engine is a variation of
the Carnot cycle called the Otto cycle. This model is a simplification of
the real world, but puts an absolute upper limit on the possible efficiency,
which is E = 1 - 1/(r exp0.4). You can find more detail at the following and
elsewhere:
http://www.physics.ucdavis.edu/classes/Summer2002/ss1/physics9B/lectures/Sec
ond_Law.pdf
For example, with a compression ratio r=8, the efficiency limit is 56%. In
practice, it's more like 30-35%. As the equation predicts, higher
compression ratios allow higher efficiency, a consequence of the higher peak
combustion temperature, which is of course why we speed freaks like high
compression engines. In this case at least, high power output and high
mileage go together.
You mention the possibility of some "catalytic role" of the 5% of the fuel
that is "cracked" by flash evaporation. I presume this would have to be some
kind of heterogeneous (gas-surface) catalysis because of the memory effect.
I guess you are suggesting that a minor change in hydrocarbon distribution
is responsible for improved combustion and mileage. This sounds like it's
equivalent to the many "additives" that purport to give you improved
mileage, performance, etc. and we all know how effect they are. For example,
here's one called GTA Fuel Enhancer with "Viscon" that makes claims similar
to the Kulasinghe device:
http://www.apdinc.com/GTAgas.html
Here's an example of something else that supposedly does the kind thing the
Kulasinghe device does, the Super FuelMAX with neodymium superconducting
magnetic resonance fuel cracking no less. Why am I so skeptical? Could they
advertise it if it wasn't true?
http://www.gas-mileage.com/superfuelmax.htm
Maybe you should ask Kulasinghe if you could borrow his Peugeot or Mercedes
for a long test drive and see for yourself just how remarkable his invention
really is. I'd definitely want some pretty convincing evidence before
risking my own money. In the meantime, I'd suggest you're safest to stick
with brewing beer.
Bob Palmer
rpalmer@ucsd.edu
rpalmer@brobeck.com
-----Original Message-----
From: owner-tigers@autox.team.net [mailto:owner-tigers@autox.team.net]On
Behalf Of Derek White
Sent: Wednesday, October 16, 2002 9:12 PM
To: tigers@autox.team.net
Subject: RE: Fuel CRACKING, non tiger
Hi all,
There have been hundreds of fuel vapour patents since the 1930's and if
there was really any advantage to them we would have seen them in
production by now. I think a lot of the companies and info on the web, in
Popular Science and other sources are scams trying to sell you magnets or
variations of the "How to build a 200mpg carb."
Dr. Kulasinghe's patents are different in that they are to do with flash
gasification (or cracking) a small portion of the fuel (about 5%) which is
then fed into the inlet manifold. It seems to have a catalytic role in
improving the combustion and reducing fuel consumption (while increasing
power.) Evidence for the catalytic role are that the improvement (fuel
saving) is immediately about 20% and then builds up gradually to 30-40% over
about 100 hours of use. The benefits (lower consumption, better power) also
linger a while after the device is switched off. The minimum fuel saving
recorded so far was 25% and the maximum was 50% (NB a 50% fuel saving means
100% more mileage!) In terms of mileage, he has achieved 66-78% better
mileage on the four vehicles (petrol and diesel) that he has conducted long
term controlled tests on.
The discovery (like many) was accidental when Dr. Kulasinghe was playing
around with various known fuel vapour systems. The rapid heating (cracking)
breaks down the fuel molecules in a different way to normal vaporisation and
this is clear from gas chromatograph analysis. For petrol (gasoline) you get
fives times more U. Butane, three times less U. Pentan, and four times more
U. Hexan when you crack compared to vaporising.
He has fitted these devices to more than 20 cars, trucks and generators
(petrol and diesel) over the last 10 years and has done more than 50,000kms
in his Peugeot and his Mercedes that are fitted with these devices.
Hydrocarbon and CO emissions were also reduced significantly, NOX emissions
haven't been tested yet.
If any of you know people working in this field (engines, fuel systems)
please put me in touch with them. The patents expire in 6 years so we want
to move quickly. Dr. Kulasinghe lost 10 years in an agreement with a local
businessman that just went nowhere.
Thanks for the ideas and help. For those really interested email me and I
can send you piles of attachments (patents, articles etc.)
cheers, derek
Derek White
37/2 Buller's Lane
Colombo 7
Sri Lanka
Tel: 94 1 581175
Cell: 94 777 475955
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