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detailed TECHNICAL info on engine (ETHANOL) modifications

detailed TECHNICAL info on engine (ETHANOL) modifications

detailed TECHNICAL info on engine (ETHANOL) modifications

(OP)
Hi,

I'm Mike from Belgium and i would like to convert my car (AUDI 80 1800S) to run on ETANOL (100% ethanol is my goal otherwise, 85% would be enough.
 
I tried to find informations on what the main differences between the engine of a FFV and that of a normal benzin vehicle are. It's not difficult to find information on ethanol fuel, but detailed TECHNICAL informations on engine modifications/ differences are what I can't find. Could someone give me some ideas/where to look/hints ...?

Many thanks,

  Mike

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

(OP)
if it's possible, i would be very interested about the modifications on the carburetor.

and if someone has an car which run on ethanol, please share your experience with me.

 tanks  

         Mike

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

There really aren't any engine modifications you need to do as far as the internal hardware goes.  Most of the work needs to be done on the fuel system and the engine management computer.  Long story short, your entire fuel system needs to be able to cope with ethanol.  While not as corrosive as methanol, ethanol still requires that the tank, pump, lines, pressure regulator, etc be alcohol compatible.  Standard rubber fuel lines will be eaten through in short order.

The largest task is going to be recalibrating the ECU on a dyno.  E85, while containing less energy per mass unit does have some upsides.  105 octane is nice because it allows more timing or boost or both while staying below the knock threshold (compared to standard 93 octane pump gasoline).

I have tuned a few turbo Hondas on E85 with great results.  Cooler exhaust temps, more power, but at the cost of worse fuel consumption.

If you have any specific questions about the conversion, let me know.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Carburetor engines don't have an ECU.

You will need to ensure all materials in your fuel system, from the tank to the inlet port gaskets are ethanol compatible. Anything methanol compatible will be good for ethanol.

You will also need to ensure the fuel pump and all fuel lines and passages are big enough to flow the extra fuel required. This includes all internal passages in the carby from needle and seat to discharge nozzle and especially transfer ports and emulsion tubes.

Fitting twice as many  carbies helps as it doubles the fuel flow potential, however it dies reduce signal to flow, unless you also substantially reduce the venturi dia in each carb.

You can normally get an advantage in fuel efficiency and power from a considerable increase in compression ratio when changing to alcohol.

The spark timing curve might also benefit from recalibrating.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

(OP)
Hi,

I need to know exactly what should i do to convert my Audi 80 1800 s to run on ethanol.

I want you (if possible) to tell me exactly what should i do from the beginning to the end.
or if you know a internet site (or a book) that could be helpful, let me know.

thanks a lot

 Mike

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Patprimmer,

I agree with everything you said except that carburetted engines don't have ECUs.  There are some carburreted engines that have a spark controller, which I would consider an ECU, albeit not like an ECU that is seen on modern cars today.


RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Mike- you might want to google more about your car, and ethanol. See if you can find an internet user group for audi/vw there is likely someone who has converted that motor already. Is it a turbo or N/A motor? I think the best gains are to be had w/ forced induction.

Pat has described the various things necessary (in general) to change a car to alcohol fuel.

In essence the Stoich AFR for alcohol is much richer... I think around 1:10 (fuel:air), and since the enthalpy of vaporization is much higher (guess) along with the flash point you can run more ignition advance and compression than with gasoline.

Thus you need to do three things: (to effectively run your car on E85, E100, etc...)

1) Provide much higher fueling to the intake charge.
2) Compress the mixture more.
3) Spark it at the right time.

you may notice lower overall fuel economy... but at least we can make more alcohol... making fossil fuels takes a long time.

Nick
I love materials science!

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

You will need another means of starting the engine.

Gas injection, or start on gas and switch to ethanol, or preheating of the fuel or the intake charge.

I almost failed geography but if I remeber Belgium is not exactly warm. Brazil even requires altenative starting means for 100% Ethanol.

I cut my lawn with a converted push mower this summer on self made ethanol. It would not start with out a drink of gas unless it was a very hot summer day.

Below 70 degrees F ethanol will not vapourize.

It is like starting a desel in extremly cold weather. Even on a average day it will not start until there is heat in the combustion chamber.

There is lots of sites on carbruator jetting for ethanol Basicaly increase the jets cross sectional area by 29%

9 to 1 is Stoch. for ethanol.



RE: detailed TECHNICAL info on engine (ETHANOL) modifications

If it has 14:1 compression it should start unless very cold. Compressing a gas makes it hot.

If you tip some ethanol on an impervious surface on a 70 deg F day, you will notice it drys quite quickly by evaporation, but it will get cold as it does. This drop in temperature due to evaporation is what makes it harder to start.

We do not write free DIY manuals here. If you can't figure it out from what has been supplied, by site rules, you really should not be here.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

If you added enough water to ethanol you could probably run 20:1 compression ratio, run a diesel engine on ethanol and substituting the injection nozzles with spark plugs.
(A gasoline engine might not be strong enough to cope with that pressure.)
The advantage would be that one could increase rpm of the diesel engine - assuming the heavier rods, pistons and ultimately the crankshaft can bear that rpm.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

if your car has lambda sensor, the ECU should be able to make the necessary fuel injector adjustment. There is a catch though, at wide open throttle, the ECU will switch to open loop meaning that it will run lean because the open loop table is calibrated using regular gasoline and not E85. If you manage to sort out the material compatibility issue caused by corrosive nature of ethanol, it is possible to run your car with E85 provided that you keep your throttle below 80%.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Azimo- and then when you need that extra 20% throttle becasue you have to make an emergency move, you get to melt your pistons.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Nicke,

at least it's possible to run it. The risk is that at WOT the AF will definitely go lean. The mitigation plan is not to go WOT.

If he wants to go WOT, buy the Flexifuel vehicle or remap the ECU.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

And how do you avoid full torque at low speeds, which might be achieved at around 50% throttle opening?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Max torque can never be achieved at low speed.

I seldom go beyond 80% throttle unless I want to overtake hard or climb very steep hill. I still have an option to lower my gear rather than having open up the throttle bigger it at higher gear. With CVT and big displacement engine, going WOT is often unnecessary, even if I have to, I can shift to L.

Low speed pinging is not very destructive. You can hear it and you can go easy on throttle.

So, back to my point, it is still possible. If you want to go WOT, go buy FFV or remap your ecu.   

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

You do not understand my point.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

what do you mean by full torque? is it max torque?

Max torque can never be achieved at 50% throttle. Max torque cannot be achieved at low rpm as well.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

By max torque I mean the full torque at that particular engine speed.

"Max torque can never be achieved at 50% throttle"

Really. Assuming by throttle you mean throttle opening, then you are wrong. If not, what do you mean by throttle? And how would you limit it to 80%?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

yup, i meant throttle opening. Everytime the throttle is less than 100%, it gives restriction to the airflow going into the cylinder. We could not reached the maximum volumetric efficiency of over 100%. When we could not reached 100% VE, we couldnot reached the max torque.

Anyhow, all the engines that i have worked on could not reached max torque with over 13 bar of BMEP. I'm interested to learn more about your engine.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Suppose you plot torque vs throttle opening at the red line.

Now plot torque vs throttle opening at half that speed.

Do you understand why there is a difference?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

yes, we have done many of that with several engines programs for many different cars.

Take x engine speed when you plot it and compare it with 0.5x. There is a difference in the achieved torque. The reason why there is a difference is that the amount of air inducted in each cycle depends on the engine speed.
 
So, i will stick with my point in my previous posting.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

If you have a very small throttle bore, you will need full throttle. If you have a very large throttle bore you can get maximum torque or even maximum power at part throttle.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Or you can drive up a hill at 2000 rpm in the highest gear and notice that the car accelerates about the same regardless whether you are at 50% or 100% throttle.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Exactly.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Pat

During engine development, we did try throttle bodie with different diameters. Between several throttle bodies, the horsepower increase by 1-3 ps at WOT

Considering the 4 bolts available at the intake plenum, i doubt if we can find throttle body big enough to enable maximum power to be achieved at part throttle.


Globi,

Without, proper datalogger, GPS, etc., I would agree with you. However, the equipment will tell different story, so I beg to be differ.

On test track, average human needs around 10-20 hp difference to notice the difference.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

Hey guys we are off on a tangent from the OP.

Azmio You seem to be talking of a specific engine where others are talking general principals.

If you now have say a 50 mm throttle plate, I am sure what you say is correct, however consider a typical American drag race engine With a hat and tunnel ram. A hat has 3 butterflys that are about 80 or 90 mm dia each. These have sufficient airflow at half throttle to have negligible increase in airflow on a 6 litre engine at 4000 rpm

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

RE: detailed TECHNICAL info on engine (ETHANOL) modifications

oh, I thought we are discussing about the Audi that Mike is thinking about running it with ethanol.

Anyhow, the principle is still the same. Though majority of the engines that i have worked on were intended for production cars, I can recall the design and operation of F1, GP1 and superbike engines that we worked on.

If you have access to the 3D CAD data or drawings, you can see how we flushed the individual butterfly throttle body with the intake port. The intake port and the throttle body is perfectly matched to avoid any mismatch that may cause losses.

Now, the throttle plate area is more or less dictated by the intake port entrance shape. Therefore I doubt that you can add any bigger throttle at the end of the development stage prior to the next race.

Remember that the intake port entrance dictates the shape of the throttle plate. By using bigger than the most optimum shape, there will be mismatch to both the intake port and variable trumpet. Any mismatch will cause several hp losses for 900hp 10 cylinder engine. In this context, even with bigger throttle body resulting the flanges mismatch, regardless of part load or WOT opening, you wont be able to get the maximum horsepower that engine is capable of producing.

Well, I never worked with engine as big as 6 liters like yours, but I think the principles are applicable to the single and also individual throttle for production and race cars.

Oh by the way, we have so many throttle opening profiles from the telemetry. You may know who the drivers or riders are. I hardly found any evidence where they spent most of the time at part load for conditions requiring every single pony from the engine. Even if we beg them to go part throttle, they will still go for full throttle opening.

Anyhow, can we get back to the original question put up by Mike from Belgium. If we ask him not to go WOT, I think he wont go WOT.

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