Alcohol and Petrol engine

[good]

Hello,
as part of my TFE, I have to do tests on an engine with a petrol / alcohol mixture.
I wanted to know how much alcohol in the mixture can I go without having to modify the engine.
What modifications must be made to the engine if I exceed this percentage?
Thank you in advance

Bgood

[Christophe]

I did not know that there was prototyping and testing during a TPE ... but so much the better

For your problem, there is very little info on it publicly. It's up to us to do them (As oliomobile did for vegetable oils) ... unless such doc exist on the net but I haven't found them yet ...

I think you can put 30% without any bp. (some oil companies already put ETBE in their gasolines, 10% modified ethanol)

After when you talk about tuning it all depends on what you are looking for:

- performance
- reduced consumption
- engine longevity
- ...

Any gasoline engine will "run" at 100% with ethanol but with perf. degraded .... since ethanol contains oxygen unlike gasoline (without carburation adjustment we get a leaner engine with the risks that this can entail). Then ethanol does not burn exactly like gasoline.

There are therefore 2 adjustments (at least) to make:

1) wealth (decrease the air)
2) ignition advance

The best would be to test on an engine with variable compression ratio since the octane rate of ethanol is higher (106 to 120 depending on the sources) than petrol.

To start I advise you to watch this video: https://www.econologie.com/video-confere ... -2991.html

Other infos: https://www.econologie.com/biocarburants ... -3503.html

[Christophe]

After some research I found some specific info on ethanol but no complete file:
Here is the article: https://www.econologie.com/bioethanol-fa ... -3020.html

So it's not 30% as I said above but "only" 10% that you can put without any modification. Beyond that I think it is necessary to adjust the richness a little (a little richer) so as not to impoverish the combustion too much ...

[Other]

Hello
commonly called alcohol does not mix well with absence
it deposits at the bottom ..
To have a performance similar to gasoline in an engine
ideally the compression ratio should be increased.
Fuel must be enriched
warm the intake air (in the case of a carburetor)
Increase the feed rate depending on the compression ratio and the fuel. (slower combustion than petrol)
But the main problem is acid formation, at the level of the exhaust valves and internal corrosion of the engine and the exhaust system, (it is for this reason that aviation is prohibited to add anti-icing products in the alcohol-based fuel)

Andre

[good]

A big thank you for this info.

I will continue my research. If I have more complete info, I would put it on the site. It could interest someone.

Thank you

[Christophe]

Hello
commonly called alcohol does not mix well with absence
it deposits at the bottom ..

This is what I noticed with methanol and oil / diesel ... but then how do oil companies manage to mix petrol and ETBE in a stable way, apparently it would be missible "naturally"?

The difference between ethanol and ETBE does not lie (I believe) in the missibility but in the higher vapor pressure bcp for ethanol (1,7 bar against 0,4 while petrol is between 0,45 , 0,90 and XNUMX). In other words: ethanol evaporates bcp + faster than ETBE or petrol ...

It could interest someone.

Me first!

Your TPE report will be welcome on the site

[zac]

Hello,
as part of my TFE, I have to do tests on an engine with a petrol / alcohol mixture.
I wanted to know how much alcohol in the mixture can I go without having to modify the engine.
What modifications must be made to the engine if I exceed this percentage?
Thank you in advance

Bgood

Hello
Specify if it is ethanol or methanol and the type of your mill and I could give you some info.
@+

[good]

No problem for the TFE.
Once finished, I will file it for you.

Otherwise, ethanol will be used.
What do you mean by mill

In any case, a big thank you for your help

Bgood

[Christophe]

Mill = motor

[zac]

What do you mean by mill

it's serious doctor; I bet it will make us an engineer or worse a teacher
@+