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Grex > Agora46 > #148: Fat Albert loses engine, dumps fuel over Seattle | |
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Message |
| 17 new of 41 responses total. |
gull
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response 25 of 41:
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Aug 14 14:34 UTC 2003 |
I think it has about the same combustibility as diesel fuel.
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russ
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response 26 of 41:
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Aug 16 13:46 UTC 2003 |
You can ignite diesel fuel by holding an open flame over a pool of it
at room temperature, no? I'd like to see you do that with fry grease.
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gull
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response 27 of 41:
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Aug 16 20:17 UTC 2003 |
I think it takes more than holding a match above a puddle of diesel to
get it to ignite, actually.
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goose
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response 28 of 41:
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Aug 17 13:52 UTC 2003 |
Yeah, it's been a while, but I remember having a hard time getting some diesel
to light with a match.
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gull
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response 29 of 41:
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Aug 17 21:44 UTC 2003 |
Gasoline, on the other hand...
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russ
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response 30 of 41:
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Aug 17 22:13 UTC 2003 |
Looks like #2 diesel has a flash point of 125 F or so. I guess that's
room temperature, if your room is in Baghdad and the power's out. ;-)
Biodiesel has a flash point well over 300 F.
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i
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response 31 of 41:
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Aug 18 02:23 UTC 2003 |
And uranium oxide *does not have* a flash point at all. Clearly nuclear
power is the way to go! :)
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gull
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response 32 of 41:
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Aug 18 12:55 UTC 2003 |
I remember the U.S. military briefly toyed with the idea of
nuclear-powered aircraft. That idea is kooky for a number of reasons,
not all of them immediately obvious. :>
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tod
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response 33 of 41:
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Aug 18 20:03 UTC 2003 |
This response has been erased.
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lynne
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response 34 of 41:
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Aug 19 17:59 UTC 2003 |
as i recall, diesel cars have to compress the fuel before igniting it.
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drew
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response 35 of 41:
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Aug 19 20:09 UTC 2003 |
No, they compress the *air* - very fast, to make it hot. This makes it hot
enough to set even stubborn-to-light biodiesel on fire, when pumped into the
cylinder.
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gull
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response 36 of 41:
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Aug 19 20:35 UTC 2003 |
Very fast, and very tightly. Compression ratios in small diesels are
about four times what they are in gasoline engines.
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drew
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response 37 of 41:
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Aug 19 21:42 UTC 2003 |
32 to 1?? Gasoline engines are usually 8 to 1 (by volume).
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i
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response 38 of 41:
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Aug 20 00:04 UTC 2003 |
Re: #34
The diesel fuel has to be under pretty high pressure to be injected into
the cylinder and burn with decent efficiency. New & higher-performance
diesels use some extremely high pressures.
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gull
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response 39 of 41:
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Aug 20 15:30 UTC 2003 |
Re #37: Hmm...yeah, you're right, it's more like 3 times higher. A 1.9L
normally-aspirated VW diesel has a 22.5:1 compression ratio. I think
the 1.6L was a little lower. I was thinking gasoline engines were
running down around 6:1 or 7:1 for regular unleaded, but a web search
shows new cars are using 10:1 on 87 octane (presumably with knock sensors.)
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russ
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response 40 of 41:
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Aug 21 01:43 UTC 2003 |
Facts: Typical compression ratios of modern gasoline engines run
from about 8.0:1 (turbocharged engine or one for low-grade fuel)
to 10.5:1 (normally-aspirated high-performance engine running on
premium gas). The diesels I've seen specs on run about 17:1.
There's a gas-turbine/diesel hybrid called a Hyperbar which gets
compression-ignition with only about 6:1 in the piston part, but
it's a funky cycle and AFAIK there are no commercial offerings.
(The outlet temperature of the turbocompressor is high enough to
allow compression-ignition with only a modest volumetric ratio,
though idling is problematic and starting requires one to spin
up the turbo first, then crank the piston part.)
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liedele
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response 41 of 41:
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Aug 28 13:51 UTC 2003 |
Gee, they could make that stunt part of their show, give ya a real thrill.
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