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Optimum Fuel Temperature? 98RON
MakeEverything - 1/6/10 at 05:05 PM

Ok, so on the back of the "refrigerated intake" thread last week, i was thinking about fuel temperature.

As Nitrogen is used in Nitrous Oxide systems to keep temperatures down in the combustion chamber, i was wondering what would happen if you chilled your juice, and would it have the same effect?

After the conversations on the last thread, im certain that you could obtain a consistent AFR if your air inlet was constant, so im now wondering about fuel temperatures to be able to run more power at a lower risk of meltdown.

Answers on a postcard please.....

scudderfish - 1/6/10 at 05:12 PM

http://wiki.answers.com/Q/How_does_temperature_affect_the_density_of_gasoline_or_petrol

MakeEverything - 1/6/10 at 05:23 PM

I was going to call you tonight, but i cant find your number!!

I was thinking more of a chilled coil that the fuel passes through rather than chilling at the tank. A temperature sensor would adjust the temperature of the coil by the fuel temperature set point. BAsic controls for what could be very effective methods of engine temperature control?

matt_gsxr - 1/6/10 at 05:27 PM

If the fuel is cold, then it doesn't disperse in the air as well. Only the tiny fuel droplets burn properly.

If you did do this, then you would want to inject the fuel ways away from the inlet, so the fuel has the best chance to absorb heat from the air (increasing the air density) and also allowing the fuel to mix up nicely.

There are specifications in motorsport on fuel temperature (there was an F1 story on this, their fuel must be no less than 10deg below ambient). http://paddocktalk.com/news/html/modules.php?op=modload&name=News&file=article&sid=69979

Matt

britishtrident - 1/6/10 at 05:55 PM

Liquid Gas Injection --- the very latest type LPG systems where the gas is injected as a liquid and due to the latent heat required for the liquid lpg to evaporate you get substantial a refrigerating effect on the incoming charge air.

MakeEverything - 1/6/10 at 06:01 PM

quote:
Originally posted by britishtrident
Liquid Gas Injection --- the very latest type LPG systems where the gas is injected as a liquid and due to the latent heat required for the liquid lpg to evaporate you get substantial a refrigerating effect on the incoming charge air.


hmmmmmmm, so maybe an LPG conversion would do that for me!!

scudderfish - 1/6/10 at 06:05 PM

If your going to do the refrigeration on the fly rather than have an insulated tank, then you'll probably spend more energy chilling the fuel than you'll get by having it chilled (if you see what I mean)

l0rd - 1/6/10 at 06:05 PM

I would be tempted to run a peltier system on copper pipes and the inlet manifold and check for improvements.

too costly though as the only place that you can notice the difference would be on RR.

l0rd - 1/6/10 at 06:16 PM

Idea

you can use a peltier system in the mounting base of a swirl pot.

I do not though if the IVA man will be happy though as peltiers use electricity. From the other point of view, same does the fuel pump.

MakeEverything - 1/6/10 at 06:22 PM

I was thinking about a copper coil around a chilled bar / coil inside an insulated sleeve.

Not familiar with the Peltier system, but ill have a look.

Car is already registered, just undergoing major heart surgery!

britishtrident - 1/6/10 at 06:27 PM

quote:
Originally posted by MakeEverything
quote:
Originally posted by britishtrident
Liquid Gas Injection --- the very latest type LPG systems where the gas is injected as a liquid and due to the latent heat required for the liquid lpg to evaporate you get substantial a refrigerating effect on the incoming charge air.


hmmmmmmm, so maybe an LPG conversion would do that for me!!


Cutting edge technolgy quote from http://en.wikipedia.org/wiki/Autogas#System_types

"Liquid phase injection systems do not use a converter, but instead deliver the liquid fuel into a fuel rail in much the same manner as a petrol injection system. These systems are still very much in their infancy. Because the fuel vaporises in the intake, the air around it is cooled significantly. This increases the density of the intake air and can potentially lead to substantial increases in engine power output, to the extent that such systems are usually de-tuned to avoid damaging other parts of the engine. Liquid phase injection has the potential to achieve much better economy and power plus lower emission levels than are possible using mixers or vapour phase injectors."

l0rd - 1/6/10 at 06:43 PM

quote:
Originally posted by MakeEverything
I was thinking about a copper coil around a chilled bar / coil inside an insulated sleeve.

Not familiar with the Peltier system, but ill have a look.

Car is already registered, just undergoing major heart surgery!


Peltiers are used in computers to lower the CPU temperature. Cool stuff, need to try it one day.


Oh, I will not be held responsible if something blows up, a fire starts or anything.

It is just an idea, easy to implement as peltiers run on 12v.

40inches - 1/6/10 at 06:52 PM

quote:
Originally posted by l0rd
Peltiers are used in computers to lower the CPU temperature. Cool stuff, need to try it one day.

I tried this a few years ago, the reverse side of the peltier needs a huge heat sink as it gets VERY hot, and major problems with condensation running on to the motherboard
Very neat unit though, if you drop water on the cold side it freezes and drop another on the hot side it boils

l0rd - 1/6/10 at 07:00 PM

quote:
Originally posted by 40inches
quote:
Originally posted by l0rd
Peltiers are used in computers to lower the CPU temperature. Cool stuff, need to try it one day.

I tried this a few years ago, the reverse side of the peltier needs a huge heat sink as it gets VERY hot, and major problems with condensation running on to the motherboard
Very neat unit though, if you drop water on the cold side it freezes and drop another on the hot side it boils


Yes, So far i have made a water cooling system with hand made waterblocks.

Peltier is the next step. I will actually make one to cool my coffee at work.

I believe though, the more heat dissipation you can transfer, the cooler it gets. So you could have a huge heatsink with a duct under the car to cool if down passively.

MakeEverything - 1/6/10 at 07:43 PM

Maximum 4A per 40mm square!!!

Jeez, ill need a generator to power them if ive got half a dozen stuck around the inlets!!

l0rd - 1/6/10 at 07:57 PM

quote:
Originally posted by MakeEverything
Maximum 4A per 40mm square!!!

Jeez, ill need a generator to power them if ive got half a dozen stuck around the inlets!!


Well, i believe the alternator should cope with this.
As i said though, This is something that needs to be done on RR to see if it is worth it or not.


Specifications:
Type: TEC1-12726
400W
12V
Couples: 127
Imax [A]: 26


So you might need 26Amps for one

[Edited on 1/6/10 by l0rd]

Toltec - 1/6/10 at 10:18 PM

Back of a forum post calc.

Lets say you have a bsfc of 300g/kwh so for 200hp that is about 12.5g of fuel a second.

Specific heat capacity of petrol is about 2.2 j/gK so you will need about 27.5W of cooling per degree temp drop at max power.

Given the fuel pump uses the petrol as coolant you would also probably want to find a way of dropping the temp as close to ambient as possible using air cooling first.

Air has a specific heat capacity of about 1j/gK so at a 13:1 mixture for every degree the fuel is below the inlet air temp the air temp should drop by about 0.15 degrees.

For comparison the latent heat of vaporisation for petrol is around 300j/g so if fully vaporised (which it is not afaik) would drop the air temp by 23 degrees. I suppose dropping the fuel temp by 15 degrees might improve charge cooling by 10%.

All top of my head so I could be completely wrong

Chippy - 1/6/10 at 10:46 PM

This post is getting me confused, surely the best combustion is to have the incoming AIR as cold as possable, and the fuel warm so that it will vapourize properly, if you inject cold fuel then surely the flame front will be slowed down due to the fuel not being totally vapourized, or am I missing something. Cheers Ray

Paul TigerB6 - 1/6/10 at 11:19 PM

quote:
Originally posted by matt_gsxr
There are specifications in motorsport on fuel temperature (there was an F1 story on this, their fuel must be no less than 10deg below ambient). http://paddocktalk.com/news/html/modules.php?op=modload&name=News&file=article&sid=69979

Matt


Correct. Cooler fuel is denser and so more (by weight) would fit in the tank if cooler, and also reduces the time taken to fill a given mass when they had refueling. Theoretically, cooler denser fuel should give more power if atomised sufficiently to combust fully - am sure in a fuel injected system that this is likely to be so.

As said though - fitting a cooling system to a car would be pointless really. Its additional power to run it, and increased weight would surely counter any potential increase in power

l0rd - 1/6/10 at 11:52 PM

well

a peltier and a huge heatsink might be about 1Kg? It consumes less power than a radio

If you have an increase of 1hp min i think it sounds good.

[Edited on 1/6/10 by l0rd]