Heated Fuel

[dremd]

Originally Posted by Christ

I accounted for that in my head... the return system is such that the fuel will have cooled by the time it reaches the tank, and even if it hasn't, a tank full of 80* fuel being squirted with a jet of fuel at less than 200* isn't going to change an appreciable amount.

The best that would happen is a few degree's change, and it will only help the case where the radiator is heating the fuel to the same temps as the coolant.

Agreed;
but there's a few ways around this. In the order they came in to my head.
1) Convert to non- return fuel system. Either the Chrysler PWM fuel pump control, or move the FPR down stream so that the fuel pressure bleeds off before the rail + heater(Diagram available on request).
2) Use a fuel sump with pump in the sump. (I built one for a 55 chevy we dropped an LT1 in to).
3) Use a great big heat exchanger that could heat that much fuel.
4) Run the fuel pump at a lower voltage. A lot of cars have a resistor inline to the fuel pump which is bypassed under high load conditions; if you ran a higher impedance ( or just 2) you could conceivably reduce the amount of bypass . . .

Just trying to help. I/ We could Definatley could be barking up the wrong tree here. . . .

[Christ]

OK, I see what you're getting at now.

It might give a slight insight toward substantial numbers, which could be something to help decide whether to experiment further or not.

I also agree that compression based ignition should be the basic model for ICE's, rather than spark based.

[MetroMPG]

From a reputable source:

I have even tested a device that completely vaporizes the fuel on a heated surface*, eliminating fuel droplets altogether, and the economy improvement was tiny (1 - 2% at most).

Part way down this page: Fuel saving gadgets - a professional engineer's view

[Christ]

Not disputing the source's claims, but if all that is precise and correct, how does the GDI engine run at 60:1 AF ratios on spark based ignition?

[forgottenmindset]

Modern Fuel Injection pressure would be anywhere from about 30psi to 60psi. (I've heard Jaguars do 200psi!).

Which would calculate to anywhere from 125 to 150 C (257 to 302F)

426.2 C (798 F) for the jag

I used a boiling point calc to figure this out, I _think_ it's accurate.

Originally Posted by cfg83

wagonman76 -



I have one but I haven't installed it. My mechanic didn't want to. If it's properly installed and a good design, then I think the main worry would be vapor lock :

Vapor lock - Wikipedia, the free encyclopedia


But, from what I have read on wikipedia, vapor lock is more of a low-pressure fuel-line carburetor issue than a high-pressure fuel-injection issue.

Here are some fuel ignition comparisons :

Ignition Temperature of Gasoline

The minimum ignition temperature at atmospheric pressure 
for some substances are: 

Carbon          400 C =  752 F 
Gasoline        260 C =  500 F 
Hydrogen        580 C = 1076 F 
Carbon Monoxide 610 C = 1130 F 
Methane         630 C = 1166 F

Question: What would the ignition temperature be at modern fuel injection PSI?!?!?!?

CarloSW2

[mfor4x4]

Have any of you guys seen a still for making moonshine? There are great ways to cool alcohol or in this case heat the fuel using these techniques. The way to put more fuel in contact with heat is to take some copper 3/8 pipe and wrap it tighly around the coolant lines. I would guess there must be some gain to heating fuel in that it only need to be heated a little more then to ignite. If you get the fuel close to its combustion temperature would you have to be concerned about preignition of the fuel?

One of the guys at work used to work for a local Toyota dealership and was talking about how they used to have to replace fuel pressure regulators on Camry's. He said that after the regulator had been replaced that the customers would complain about the fuel economy their Camry's were getting. He said that the Camrys had a little hesitation but excellent fuel mileage just before the regulator went. Has anyone tried to play with their fuel pressure settings?

On the propane topic, I know a guy who drag races an Oldsmobile with a 455 Rocket that is turbo charged on propane, he has said that he can run insane compression ratios with propane and a turbo on these engines. Have any of you considered increasing compression ratios also, this works very good with pure ethanol or E85 even. Ethanol has less BTU than gsaoline but a higher octane which would alow you to run higher compression ratios which, make an engine run more efficiently.

I know I am new to the forums, I really enjoy them too. I am hoping to use the info from you guys to help me get amazing FE from my newly purchased '97 Metro.

[orange4boy]

My thinking on this is that from a practical ecomooder point of view, it would be a much better idea and give greater returns to heat the air rather than the fuel because:
1. Fuel is already heated passively by proximity to the engine. It moves relatively slowly through thin metal tubes so has lots of time to heat up. Most injectors are practically in the combustion chamber.
2. Being only 1/14 to 1/16 of the mixture makes it less important than the other 13-15 parts.
3. Injectors do a great job of vaporizing the fuel already.
4. The air intake in most cars is not heated whereas all fuel is passively heated.
5. you will have to get that fuel pretty darn hot to beat the existing temperature.

The short version: WAI easy, PHF, hard.

The general idea is good though.

BTW in propane fired glass melting furnaces preheated air is a big savings because the fuel does less work to heat up the air and thus less fuel is required to achieve a given temperature but this is a different application because all you want is heat there is no mechanical conversion of energy required.

The real question to answer here is how much more efficient is a hot bang compared to a cold one?
In other words, can you get more BTU's out of a hot bang or a cold one?

Has this already been answered here?

[Christ]

The only real benefit I can see to heating your fuel is that it will keep combustion temps up... i.e. the fuel won't be leeching as much heat from the combustion chamber as it is sprayed in, resulting in a hotter combustion chamber, which technically is more efficient.

By the way, the restrictive nature of OEM intakes on most cars, coupled with the fact that it has to travel through a heated throttle body, into a hot intake, means that it is in fact heated, extensively, from the initial temp of intake.

[Christ]

mfor4x4 - is he running propane as an additive or a primary fuel?

I ask because you can use propane to quench detonation when the fuel system can't handle the amount of airflow you get from the turbo. Alot of diesel performance companies also provide propane kits and nitrous kits that you use in tandem... it creates an almost infinite power adder... since you can turn up the compressed fuel and air until the engine just can't hold any more. (Nitrous is an oxidizer, for those that don't know... if you use too much, you lean out the mixture, which can cause engine damage... add propane as a fuel, and you're good again. Same applies for boosting beyond the fuel system's capabilities.)

BTW, cheap race fuel = add Xylol to your gas. It's already in there naturally, and has 117 Octane rating... do the math.

[mfor4x4]

He is using propane as the primary fuel source. I would have to ask him what compression ratio he is using. I know he has 1 turbo mounted on his one car and 2 turbos mounted on his other drag racing car. The one car is using a turbo off of a 6.5L GM diesel, I think he using Holset turbos from Cummins turbo Diesels on his other car (don't quote me on that though).

BTW, why use high octane fuel if your engine can't use the extra power in it?