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3145 MPG

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General interest discussions, not necessarily related to depletion.

Re: 3145 MPG

Unread postby kaktus » Mon 28 May 2007, 05:28:59

$this->bbcode_second_pass_quote('', 'k')aktus wrote:
Surely you dont mean...
Generally most sentences that begins with these words mean that the author understands what is meant and is just being picky.


Or perhaps you cant geta hint that you are saying something stupid.:)
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Re: 3145 MPG

Unread postby whereagles » Mon 28 May 2007, 09:45:10

$this->bbcode_second_pass_quote('kaktus', 'G')reat, do you know anything about the engine and contol electronics? I saw the common way is to use a 50cc engine, but not more.
I'm not a technician, just curious.


I don't know details about my institute's model. What I do know is:

- The engine has been around for a while, and it's being improved continuously. I belive it's a 1-cylinder diesel, but not sure.
- It vehicles moves at 30 km/h (~18 miles/h).
- It came 11th at the shell eco-marathon this year.

Next year it's supposed to get a new engine, based on the current one, but with improvements.
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Re: 3145 MPG

Unread postby Hawkcreek » Mon 28 May 2007, 19:40:47

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Last edited by Hawkcreek on Thu 23 Aug 2007, 14:00:01, edited 1 time in total.
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Re: 3145 MPG

Unread postby whereagles » Tue 29 May 2007, 10:06:41

$this->bbcode_second_pass_quote('Hawkcreek', 'A') steam car could run an hour on 25 pounds of good firewood. Maybe we should go for steam?


Steam engine thermodynamical efficiency is 5-10%, maybe 15% in lab conditions. Gasoline engine is 15-25% - much better.
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Re: 3145 MPG

Unread postby steam_cannon » Thu 31 May 2007, 16:26:30

$this->bbcode_second_pass_quote('whereagles', '')$this->bbcode_second_pass_quote('Hawkcreek', 'A') steam car could run an hour on 25 pounds of good firewood. Maybe we should go for steam?


Steam engine thermodynamical efficiency is 5-10%, maybe 15% in lab conditions. Gasoline engine is 15-25% - much better.
True, but many other factors play into fuel and engine choice.
Thermodynamics, transport cost, availability and EROEI...

For wood, the EROEI can certainly be better then a depleted oil deposit and you don't have to rely on an oil company for it. Gasifying hay to run farm tractors is another example.

Regarding coal, lets say:
1 ton of coal =< 63 gallons of gas, 1.5 barrels of fuel

Lets also say all that fuel is gasoline.

1 gallon gasoline 125,000 Btu

1 ton coal 16,200,000 to 26,000,000 Btu

63 Gallons of gas * 125,000 Btu = 7,875,000 Btu

And lets say that...
Auto efficiency 25%
Steam efficiency 8%

But since both engines are using coal...

16 200 000 / 7 875 000 = 2.05714286 twice less energy

Engine efficiency divided by energy lost in processing.
25/2.0

So compared to burning coal directly, an auto engine burning coal based fuels may have a total process efficiency more like 12.5%

Conclusion: engines using coal liquids are 12.5% efficient

I suspect there are better ways to calculate that, but I'm just saying efficiency of the engine isn't the only factor. Since both are using coal, total process efficiency must be accounted for. Like how compressed air engines are highly efficient, but where the power comes from to compress the air also needs to be accounted for. Or like converting coal to hydrogen to fuel a car, big energy losses there too...

So an engine that burns coal, oil, wood or straw might have practical advantages. Just as using a combined cycle gas turbine of 50% to 60% efficiency to produce electricity for electric car batteries, might be competitive with coal to liquids. So you know, maybe 8% efficiency from directly burning coal in a steam engine would be competitive with coal to liquids schemes.

"In practice, a steam engine exhausting the steam to atmosphere will have an efficiency (including the boiler) of 1% to 8%, but with the addition of a condenser the efficiency may be greatly improved. A power station with steam reheat, etc. will achieve 30% to 42% efficiency. Combined cycle in which the burning material is first used to drive a gas turbine can produce 50% to 60% efficiency. It is also possible to capture the waste heat using cogeneration in which the residual steam is used for heating. It is therefore possible to use about 90% of the energy produced by burning fuel—only 10% of the energy produced by the combustion of the fuel goes wasted into the atmosphere."
http://en.wikipedia.org/wiki/Steam_engine#Efficiency

steam car
http://www.stanleysteamers.com/modern_steam.htm

steam jet boat
http://www.newscientist.com/article.ns?id=dn3321

Steam Bicycle
http://www.users.globalnet.co.uk/~pattl ... rc0373.htm

Personally, despite my nick I favor solar, gasification, and gas to liquids more then steam for practicality, but steam still has potential.

Well my teakettle is whistling! :)
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Re: 3145 MPG

Unread postby WisJim » Thu 31 May 2007, 23:15:23

To get back to the topic of 3145mpg etc., back in 1992 or so Road and Track (american car enthusiast magazine) took a new at the time Geo Metro XFI and a Honda Civic VX (the high gas mileage models of the 2 cars) and drove them the way the gas mileage contest cars are driven. They got 104+mpg in the Honda, and 116+mpg with the Geo, using the "pulse and glide" driving techniques used in the small experimental cars.

http://metrompg.com/posts/xfi-pulse-and-glide.htm
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Re: 3145 MPG

Unread postby steam_cannon » Mon 04 Jun 2007, 16:46:50

$this->bbcode_second_pass_quote('WisJim', 'T')o get back to the topic of 3145mpg etc., back in 1992 or so Road and Track (american car enthusiast magazine) took a new at the time Geo Metro XFI and a Honda Civic VX (the high gas mileage models of the 2 cars) and drove them the way the gas mileage contest cars are driven. They got 104+mpg in the Honda, and 116+mpg with the Geo, using the "pulse and glide" driving techniques used in the small experimental cars.

http://metrompg.com/posts/xfi-pulse-and-glide.htm
The only way I could see pulse and glide working on a personal scale would be in a futuristic scifi world where everyone's car is computer controlled. But I agree the pulse and glide research might be of benefit to engineering better public transportation like rail transport.

Pulse and glide efficiency

Honda Civic VX normal driving 55 mpg
pulse and glide 104 mpg

So what kind of practical mileage would a 3145mpg vehicle get, 1572 mpg? That would be impressive.

$this->bbcode_second_pass_quote('kaktus', 'a')lso the challenge is to use 1 litre of gas or EQUIVALENT energy amount.
Also, what are peoples thoughts on "equivalent to 1 liter of gasoline"? A large air tank might hold as much energy as 1 liter of gasoline, but might take 2 real liters of fuel to pump it up. I wonder how are fuel equivalents being accounted for in these studies? Well, probably only an issue of you are using fuels that go though multiple conversions like coal liquids...
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Re: 3145 MPG

Unread postby yesplease » Mon 04 Jun 2007, 17:28:31

$this->bbcode_second_pass_quote('Plantagenet', 'Y')ou can get a zillion times better gas mileage on a bicyle. [smilie=5moped.gif]

Not if you count the fossil fuels needed to grow your "fuel". Then you're down to ~100-200mpg, and only at ~15mph. I'd rather nab a 3L Lupo and pull ~100mpg@55mph for anything farther than a few miles. Bicycling hundreds of miles for some ill conceived environmentalism isn't my cup of tea. :P
$this->bbcode_second_pass_quote('Professor Membrane', ' ')Not now son, I'm making ... TOAST!
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Re: 3145 MPG

Unread postby tsakach » Mon 04 Jun 2007, 17:57:20

This vehicle travels 53 miles on 1 kilowatt hour, reaching top speeds of 55 mph:
Image
These vehicles get the equivalent of 1500 mpg, and are built by high school students for an average cost of few thousand dollars.

$this->bbcode_second_pass_quote('', 'A')n Electrathon vehicle has three or four wheels and is powered by an electric motor running off batteries. Electrathons are raced under rules which specify matters such as length and width of the vehicles (12 feet long and 4 feet wide maximum) and total weight of batteries (64 pounds for lead-acid batteries, a few more for gel cell battereis), with the weight of the drivers being ballasted to 180 pounds.
The relatively low cost of the electrathon racing has made the sport a popular activity for high school age students world-wide who learn skills related to design, problem-solving, teamwork, math, physics, and electricity.

At present, the world record for distance travelled in one hours time is 53 miles.

EV world, Electrathon

Image
Electrathon Racing
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