how about a fuel heater?

[bandit86]

was watching some bonfires the other night and thought to myself, since gasoline evapourates faster then water, why not add a small heater and heat my injector rail to about 180degrees F .The hot fuel would immediately boil when released from the injector, causing complete atomization. maybe loop it back so that it doesnt heat the entire tank, just the rail

[Frank Lee]

I suppose that's better than heating the fuel line with a bonfire.

[Old Mechanic]

Transonic Combustion | Ultra-high Efficiency Fuel Injection Systems

Supercritical ultra high pressure injection, multifuel capable.

regards
Mech

[nibs]

I put in a fuel heater on my 6V92 diesel, and my mileage went up from 7.4mpg to 7.9mpg. The heater I used was intended for trucks running in sub-zero weather, I found it at a junk yard, and installed it to help with warming the WVO I used to mix with the petro diesel. If and when I get motivated (or rich enough) I will put one on my 300D. First post on eccomodder - great site and thanks for letting me in.
Tony

[bandit86]

I wasnt thinking direct injection, just a regular fuel injected gasoline engine

[nibs]

I don't know why the fuel heater improved my diesel mileage, possibly the fuel is expanded or possibly it gives a better spray pattern and ignites more readily, either way, would like to know if others have had a similar experience.
There are a number of heat exchangers both electric and coolant heated on the market, if i was using one for gasoline, I think a coolant heated exchanger would be safer.

[mwebb]

bad idea
fuel is about 1 15th of the Mass of the air fuel mixture prior to combustion assuming the engine runs at or close to stoich or Lambda of 1 ,
heating the air will have a much greater effect
and
heating the air has been experimented with a whole lot in the pages of this forum

so you can read up on the success or lack thereof of current and past experimentation regarding WAI

you can learn from the pain of others , if you have your wits about you and make your own informed choice

those who will not learn from the mistakes of history
are doomed to repeat them

Originally Posted by bandit86

I wasnt thinking direct injection, just a regular fuel injected gasoline engine

..."I suppose that's better than heating the fuel line with a bonfire."...

yes .

[Nerys]

mwebb you say its a bad idea but Fail to actually tell us WHY its a bad idea.

Care to clarify? I have no doubt your right but for me and likely others such is not good enough. I wish to know WHY its a bad idea.

[ShadeTreeMech]

Vapor lock was a common occurance on older carburated engines, and the cause was overheated fuel in the lines. The net result was not being able to start the engine.

I would think warmer fuel would be fractional thinner, and therefore would come out of the injectors faster (maybe uncontrollably?) and best case scenario might possibly net worse economy. Worst case you have a volatile combustable chemical that now has more energy instilled in it already and could possibly explode easier; good thing if it happens in the cylinder, bad elsewhere.

The fuel that goes into the fuel rail generally also returns to the tank, so the fuel in the tank would warm up, which would encourage evaporation. How will the evaporative canister handle the extra vapor? I don't know. Can you loop the fuel back into the rail? sure you can, just crimp the return line; it works in a pinch (BAD PUN ALERT!) if the pressure regulator goes out. But this would likely cause worse fuel mileage unless the injectors were configured for higher pressure (I assume...) i would assume the higher pressure would strain the fuel pump, possibly causing premature failure. Electric motors cope with additional strain by drawing more amps which causes things to heat up. A hot fuel pump isn't necessarily dangerous, but it will eventually fail. Considering a normal fuel injected engine has the injectors millimeters away from a VERY hot arena, I suspect those gas molecules are vaporized very well by the time the spark goes off. So it may be a moot point.

as mwebb pointed out, heating the air will have a bigger effect, especially considering the amount of it being used. And I've yet to hear of an explosion from overheated air. And it'd be quite easy to rig up a HAI compared to heating up gas under pressure, and likely a bit cheaper. I'm actually toying with the idea of pulling in intake air from the nether regions of the exhaust pipe to warm things up a bit. A bit of exhaust is bound to lower my pumping losses and raise the temp of incoming air.

I was just rereading the post and realized an important point. The assumption behind wanting to heat the fuel is to hopefully extract more energy from the fuel. I wonder then, what percentage of the fuel is combusted in a well maintained engine? Seems I haven't smelled a modern car running "rich" unless the o2 sensor went out or some other important component was faulting, so it makes one wonder if heating the fuel will extract anymore energy out without a redesign of the engine itself.

[Old Tele man]

...two points to remember:

1) the gasoline evaporates into the air, not the other way around; and,

2) typically, there are 14.7 parts of air for every 1 part of gasoline vapor.

...hence, air "rules" by sheer magnitude.