PDA

View Full Version : Pre-heated Gasoline Improves Mileage?



sarongsong
2007-May-14, 11:47 PM
A phone-in caller to Art Bell last night reported wrapping the gasoline fuel line around one of the engine's radiator hoses several times for heat, resulted in going from 14/mpg to a quite impressive 40/mpg on his 1979 Chevrolet pick-up truck. (Art asked him to mail him the details and would look into it.)
Any obvious scientific justification here for such a claim?

dgavin
2007-May-15, 12:19 AM
Hmm, I wouldn't expect -that- kind of improvement, but irregardless evaporating the fuel completely has some god point, but my bad points.

Preheating gasoline has dire concequnces for an engine. They are built specifically for a slow burn of partialy evaropated (or atomized) gasoline.

Preheating the gas so it totaly evaporates, would result in the gas air mix litteraly exploding instaneously in the cylinder. It provides much much more power, but reaches a burn temperatures of around 1300 F instead of the normal 480 F, whick will warp/damage even cast iron engines of those days.

It's a total no go for any engine with aluminum parts.

In other wards you would need an engine designed for that kind of heat disapation. Allison aircraft engines are the only engines I know of designed to burn fuel in this manner.

And it would only work with fuel injection, as a carborator has a fuel bowl with a float mechenism, which evaborated gas couldn't ever fill.

Additionaly, any fuel leak in his heating aparatus would result in fuel line fire. Definately not a good thing there. Allison has this built into thier engines by heating the air/fuel after mixing, buy the use of a special heat exchanging manifold. Really the only safe way to do it.

TheOncomingStorm
2007-May-15, 12:45 AM
This would be something interesting to see them do on Mythbusters.

Van Rijn
2007-May-15, 01:04 AM
A phone-in caller to Art Bell last night reported wrapping the gasoline fuel line around one of the engine's radiator hoses several times for heat, resulted in going from 14/mpg to a quite impressive 40/mpg on his 1979 Chevrolet pick-up truck. (Art asked him to mail him the details and would look into it.)
Any obvious scientific justification here for such a claim?

Phone in to Art Bell?:)

Short answer: No, a leap from 14 mpg to 40 mpg is unjustifiable. There are various ways to make use of some of an engine's waste heat, with various issues, but you aren't going to get nearly three times the MPG with anything simple. This reminds me of the 100mpg carburetor claims you'd see in the '70s.

sarongsong
2007-May-15, 01:44 AM
...evaporating the fuel completely has some god point, but my bad points.
Preheating gasoline has dire concequnces for an engine...The raised temperatures the guy mentioned were in the 160-180 F. range, claiming 'cold' gasoline wasn't as efficient as 'warm' gasoline.
Yes, it is reminiscent of the infamous 100/mpg carburetor, and it was Art Bell's show, but had not heard this hypothesis before.

publius
2007-May-15, 02:58 AM
Yeah, he said he was simply heating the liquid via a heat exchanger with coolant.

If he was seeing that much improvement in mileage, I suspect he may perhaps be the victim of a little practical joke played on someone around here years ago. This fellow bought a new car that was supposed to get better mileage, and he went on and on about it, sort of miffing everyone.

He would drive it to work every day. Late at night, every night some of his friends would sneak over and add some gas to the tank. They wouldn't add enough to be obvious, just enough to greatly skew his mileage calculations. :lol:

He bragged and bragged about the amazing mileage he was getting. They did that for several weeks, and then..........they stopped. His mileage now went way down. He thought something was wrong and took it back to the dealer, and pestered them about it. They of course could find nothing wrong, and the figures he quoted were right in line with what it was supposed to be.

They let that go for months before they finally told him what they did.....................

Nowadays, gas is getting a might bit expensive for that kind of prank, but it was a hoot.

-Richard

novaderrik
2007-May-15, 03:48 AM
the only way this would work very well at all would be with a direct injection setup like on newer diesel engines. unlike a conventional fuel injection setup that sprays the fuel into the air stream sometime before going thru the intake valve, the fuel would be injected directly into the combustion chamber just a fraction of a second before the cylinder reaches maximum cylinder pressure and right before the spark plug ignites the mixture.
right now, it's just a matter of development and cost effectiveness. and, of course, waiting for someone's patent on something to expire, so they can start to make money on this awesome "new" technology instead of that ancient old technology.
there are a few cars out on the road right now with direct fuel injection- the Pontiac Solstice GXP being the only one i can think of right off the top of my head- but i don't think any of them pre-heat the fuel before squirting it into the chamber.
on a slightly related note, i was reading on www.chevelles.com a week or so ago about an engine design patented by a man by the name of Smoky Yunick back in the 60's or 70's that was supposed to be good for 150hp and 50 mpg out of a 2 cylinder engine. since it was before engine electronics, it had a carburetor to mix the cold air and fuel before it got preheated by hot coolant to 90 degrees C and sucked thru a turbocharger that not only compressed it all, but also raised it's temp again using exhaust heat to something like 200 degrees C before getting rammed into the cylinder to be squeezed and lit.
really a rather interesting design- and pretty high tech for a guy that was self taught and worked out of a small shop called "the best damn garage in town" in Daytona Beach, Florida.

NEOWatcher
2007-May-15, 01:08 PM
on a slightly related note, i was reading on www.chevelles.com (http://www.chevelles.com) a week or so ago about an engine design patented by a man by the name of Smoky Yunick back in the 60's or 70's that was supposed to be good for 150hp and 50 mpg out of a 2 cylinder engine.
Well; that's the rumor...
Smoky was a regular contributer to Popsci in the 70's, and I did enjoy his articles. But the claim that you mention has many holes in it.
Yes; it is a patented design for the adiabatic engine. It was patented in 1984.
The claim is only theoretical, it was never proven.
You need to consider the vehicle that the engine is in before you can claim mileage of an engine.
The intended vehicle was a Pontiac Fiero which was already capable of 40 mpg highway.
A turbocharger by itself would increase milage.

And heating the gas? How does that affect the energy potential? Wouldn't the only gain be in the completeness of the burn? Or, maybe recapturing a small amount of heat loss from the engine?

novaderrik
2007-May-15, 06:39 PM
preheating the gas causes it to vaporize more completely, so it burns better and more of it's potential energy gets used to push down the piston instead of getting shot out the exhaust unburnt. small droplets burn better than big droplets.
right now, from what i've read, the only real technical problem is keeping the fuel from boiling into a useless gas before getting injected- vaporlock- but that should be easily overcome. just like any other fluid- raise the pressure, and you raise the boiling point.
and i've never heard of a Fiero that got 40 mpg- there might be a few 4 cylinder versions that are getting close to 30, but not 40. the 2.5 liter they put in them wasn't exactly an efficient design. now, put a newer 2.0 Ecotec out of a Cobalt in there and tune it properly, and i bet 40mpg could be seen.

Pinemarten
2007-May-15, 06:47 PM
Google Pogue Carburetor.

U of Calgary built one years ago an got about 150mpg with a 1968 Ford 289V8 on a track.

Pogue had a heat exchanger that used exhaust gas and replaced the carb. It actually evaporated the gas and sent it down the manifold at around 12-16 PSI.
I will see if I can find a link.

A friend of mine bought a '72 Newport(400V8) from an old timer years ago. He had made an adaptor plate between the carb and manifold with 2-4 .25 to .5" copper pipes in it that channelled water from the 'hot' hose on the radiator. Once it hit operating temperature he went from 18mpg to 25-35mpg.

I had another friend that built and sold 'water injectors'. He put in a container of water with a small (secret size) venturi that sucked small amounts of the water in through the vacuum system. They increased mileage by 15-40%. Alcohol worked better if you could find a cheap source of it.

Edit: Found link to the patent diagrams:
http://www.rexresearch.com/pogue/1pogue.htm

NEOWatcher
2007-May-15, 06:53 PM
preheating the gas causes it to vaporize more completely, so it burns better and more of it's potential energy gets used to push down the piston instead of getting shot out the exhaust unburnt.
Does that much still remain unburnt in today's engines?


...and i've never heard of a Fiero that got 40 mpg- there might be a few 4 cylinder versions that are getting close to 30, but not 40...
Got that from the Highway milage on Wiki. I did have friends that had Fieros who got mid to upper 20's regularly with hard driving, so at minimum 30's on the highway doesn't sound too out of line.

Ronald Brak
2007-May-15, 07:21 PM
Does that much still remain unburnt in today's engines?

You can smell it in the exhaust. Breath deep when older, poorly tuned cars drive by. But no, not in modern cars.

NEOWatcher
2007-May-15, 07:31 PM
You can smell it in the exhaust. Breath deep...
Yea, I'll get right on that once I finish that pack of Marlboros. ;)

Pinemarten
2007-May-15, 07:51 PM
Here's an interesting one. Did the Pogue actually 'crack the gas'?

http://freeenergynews.com/Directory/Carburetors/McBurney/cracking/

McBurney proves his system with "UV spectrum analysis and gas chromatography".

"Gallon for gallon, natural gas and methanol burn approximately as efficiently as gasoline. The efficiency of McBurney's system comes because by using this process of 'cracking' the fuel, one gallon of gas with two gallons of water will produce four to five Gallons of natural gas and methanol."

NEOWatcher
2007-May-15, 08:05 PM
"Gallon for gallon, natural gas and methanol burn approximately as efficiently as gasoline. The efficiency of McBurney's system comes because by using this process of 'cracking' the fuel, one gallon of gas with two gallons of water will produce four to five Gallons of natural gas and methanol."...
Using two to three gallons of equivelent energy to perform this cracking?

Pinemarten
2007-May-15, 08:07 PM
Water injection works?

http://peswiki.com/index.php/Directory:Fuel_Efficiency_Retrofits#Water_Injectio n

Pinemarten
2007-May-15, 08:09 PM
Using two to three gallons of equivelent energy to perform this cracking?

I think he gets the energy from the exhaust heat.

NEOWatcher
2007-May-15, 08:12 PM
I think he gets the energy from the exhaust heat.
I kind of got that idea, but the article never really related how much of this heat is recaptured compared to how much is needed for the cracking compared to the initial input. In other words, is it efficient enough to sustain itself.

Pinemarten
2007-May-15, 08:18 PM
I kind of got that idea, but the article never really related how much of this heat is recaptured compared to how much is needed for the cracking compared to the initial input. In other words, is it efficient enough to sustain itself.

The same friend that was building the water injectors, had another friend that built a Pogue type thing.
He said the first models did get too cold after a while, so he just added some type of manual valve that he adjusted while watching a temperature gauge. The mileage turned to crap until the temp was up again.

novaderrik
2007-May-15, 08:49 PM
water injection systems are readily available. mostly, they are used in turbocharged and supercharged engines to help prevent pre-ignition and allow a more complete burn of the fuel. you can also get methanol injection setups that use readily available winter blend windshield washer fluid that contains methanol.
i'm not sure of the exact numbers, but even the best internal combustion engines out there are something like 30% efficient at converting the fuel into power to drive the wheels. and those are the most efficient highly tuned race cars. a good street engine is right around 20%. that is a lot of wasted energy that is gone thru friction and all that exhaust heat going out the tail pipe. anything that can be done to efficiently recapture some of that lost heat- either in the coolant or in the exhaust or a combination of both- and put it to use should pay off in increased efficiency.

Van Rijn
2007-May-15, 09:31 PM
Smoky was a regular contributer to Popsci in the 70's, and I did enjoy his articles. But the claim that you mention has many holes in it.
Yes; it is a patented design for the adiabatic engine. It was patented in 1984.


I remember those articles. He often had (unfriendly) comments on supercarbs and other suggested magic bullets for fuel efficiency. He mentioned the adiabatic engine more than once, but I think part of the problem was building an economical engine that would have a long lifetime. By the way, it seemed like he just disappeared from PopSci (at least, I don't recall any statement why he was no longer writing for them and why they were no longer referring to him). I always wondered if something had happened behind the scenes.

As an aside, I got a kick out of this:

http://en.wikipedia.org/wiki/Smokey_Yunick#Automobile_racing

which shows some of the tricks he used to stay within the letter of the rulebook for racecar design. In one case, he built a 7/8 scale model of the regular car!

JohnD
2007-May-15, 10:29 PM
Oh, come on Wake up.
"Pogue had a heat exchanger that used exhaust gas and replaced the carb. It actually evaporated the gas and sent it down the manifold at around 12-16 PSI." Thata's compared with normal atmospheric of 13 psi, or above atmospheric? Either way, he had a Turbo or supercharger. More fuel/air = more power.

Water injectors are used to COOL the mixture in the chamber when using a super/turbo charger, to prevent the stuff exploding ("Detonating" - it destroys pistons)

The whole theory and practice of automotive air induction is to get as much air into the carbs/intake as possible that is COOL, as cool air is denser air that contains more oxygen. Kore oxygen acn burn more fuel and make more power, more efficiently.

The advantage of methanol is that it resists pre-ignition - has aavefy high octane rating, so that a higher compresion ratio can be used (like <14:1 instead of <10:1 with petrol at 98 octane) The higher the compresison ratiom the more efficient the engine. But cracking ordinary petrol with water? Build your own distillery?

Smokey Yanucjk was a master, and I'm sure he had 150hp and 50 mpg out of a 2 cylinder engine. Have you heard of motorbikes?

Gods, you guys are gullible. Believe any flimflam artist who appears on a TV show.

sarongsong
2007-May-15, 10:34 PM
I also heard (no references) he was involved in developing a ceramic engine near the end of his career.
This page is a translation from the Swedish "Hot Rod Magazine". It was published 1984...Besides building a 1-, 2- and 3-cylinder himself, Smokey has successfully converted existing 4-cylinder engines.
Car/engine...................Fuel consumption.......0-100 km/t
Pontiac Fiero, 4-cyl..........21.97 mil/gal...........14.2 sec.
Pontiac Fiero, Hot Vapor...51.10 mil/gal.............5.9 sec.
..."It is really quite simple, and I am careful not saying too much. This is the only way I can be sure nobody knows how the system exactly works," says Smokey...
schou.dk (http://www.schou.dk/hvce/?mode=2)

Van Rijn
2007-May-16, 12:10 AM
Gods, you guys are gullible. Believe any flimflam artist who appears on a TV show.

Which "you guys" are you referring to? As I said earlier, a leap from 14 mpg to 40 mpg is unjustifiable.

novaderrik
2007-May-16, 01:04 AM
The whole theory and practice of automotive air induction is to get as much air into the carbs/intake as possible that is COOL, as cool air is denser air that contains more oxygen. Kore oxygen acn burn more fuel and make more power, more efficiently..
ideally, you'd get lots of cool air into the carb- more oxygen content- but after that, you'd want to heat it up so it vaporizes the fuel better once it's introduced into the equation. a hot air/fuel mixture can more easily release more energy out of the fuel.
i've done some playing around with this myself, trying to get my brick (1974 Chevrolet Monte Carlo) to get better mileage. the best i've gotten so far has had cold air rammed into the carburetor with my custom home made air cleaner that uses clothes dryer tubing to jam cool ambient air into the air cleaner from behind the grille, with the intake manifold heated up by the exhaust crossover. just having that crossover full of hot exhaust gasses is worth a couple of mpg, and it seems to run smoother.
it also runs better and uses less gas if i can keep the coolant temps up around 220 at highway speeds- but that's kind of tricky, what with the hottest thermostat rated at 195, and the amount of the grille i block off to limit airflow thru the radiator has to be changed depending on the weather conditions. of course, blocking off the grille openings also catches less air under that huge hood, which creates less aerodymanic loading.

Pinemarten
2007-May-16, 09:21 PM
Oh, come on Wake up.


Gods, you guys are gullible. Believe any flimflam artist who appears on a TV show.

Watch the Ad Hom, I'm not impressed!

And all this research, studies, and evidence were by gullible people?

http://peswiki.com/index.php/Directory:Fuel_Efficiency

http://peswiki.com/index.php/Directory:Fuel_Efficiency_Retrofits#Water_Injectio n

http://www.himacresearch.com/books/crisis1.html

http://freeenergynews.com/Directory/Carburetors/McBurney/cracking/

http://www.sjvls.org/bens/bf012fc.htm

http://blog.hasslberger.com/2007/04/pogue_carburetor_gasoline_vapo.html