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Author Topic: Alcohol in smaller engines  (Read 7720 times)

MoHillbilly

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Alcohol in smaller engines
« on: August 31, 2006, 08:54:31 PM »
Just wondering here, has anyone ever ran 100% alcohol in a smaller gas engine?  In particular, an Onan.  I have had this genset for years, and would really like to try it out on "shine"....  Its a 1971 4Kw out of an old winnebago. It runs like a top on gasoline, and even 10%  ethanol blend, but 100% alcohol, never tried it.   

Any suggestions or ideas on what to do to make it run properly? mixture settings, spark advance/retard, power increse/decrease?    Getting sick and tired of these damned 200 dollar electric bills, and i cannot afford a listeroid genset right now, (cant afford not to have it either! )  So I would really like to get this unit up and running on alcohol if possible, would really help out on the electric bill!!!!!

slowspeed1953

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Re: Alcohol in smaller engines
« Reply #1 on: August 31, 2006, 10:11:22 PM »
Dont run ethanol unless you are ready to have a engine burns cleaner runs better and can go two to three times as long without changing the oil.

I ran a old briggs engine on the sauce and did nothing other than choking it a little, I would do the same with the Onan. The briggs did not have an adjustable main jet if your Onan does simply adjust the main and idle air jets to get smooth operation. If it does not have an adjustable main jet get yourself a set of number drills for main jet enlargment. Start with the next larger drill and open up the main jet then run the engine, you will probabally need to still use the choke to get the mixture fat enough. Keep enlarging the main jet until the choke is not needed to allow a warmed up engine to run smooth.

Peace&Love :D, Darren

MoHillbilly

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Re: Alcohol in smaller engines
« Reply #2 on: September 02, 2006, 01:34:50 AM »
Thanks for your input Slow!

Looks like i can get a still gong WAY cheaper than a new genset...especially with my scrounging around skills!

cujet

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Re: Alcohol in smaller engines
« Reply #3 on: September 03, 2006, 01:34:46 PM »
Alcohol has some advantages. Check this out, It explains a lot.

http://www.dirtrider.net/forums3/showthread.php?t=115212
People who count on their fingers should maintain a discreet silence

Doug

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Re: Alcohol in smaller engines
« Reply #4 on: September 03, 2006, 06:49:58 PM »
If your going to build a still you stand to make enough money the buy fuel oil if you develop any sort of skill using it lol.

On a serious note, I have read a few intersting pieces on fuleing diesels with Alcohol foggers. I don't much about it but it sounds like another option for the Listeroid DI engines, not so much for the IDI.

Doug


biobill

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Re: Alcohol in smaller engines
« Reply #5 on: November 20, 2006, 10:17:52 PM »
  There is a class in kart racing that uses 5hp Briggs running on methanol. The rule of thumb was to double the main jet size to put you in the ballpark. Nice thing about meth is it doesn't mind running a little rich. If I recall correctly, the idle mix could be dialed in by closing the air screw to about half it's normal setting. Alcohol has very poor lubricity properties so add some Marvel Mystery or 2 stroke lube to your fuel. Can't remember the ratio but it wasn't much.

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6/1 Metro DI living in basement, cogen
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VW 1.6 diesels all over the place
Isuzu Boxtruck, Ford Backhoe, all running on biodiesel
Needs diesel lawnmower & chainsaw

aqmxv

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Re: Alcohol in smaller engines
« Reply #6 on: November 21, 2006, 04:24:22 AM »
Fueling an Otto-cycle engine with either Ethanol or Methanol is pretty well-explored turf.

The good:
Higher octane number than most gasoline you can buy

Stoichiometric mixture is almost twice the fuel flow - lots of mixture cooling via evaporation and chamber cooling as well during intake stroke.

Low boiling point and limited miscibility with oil means that it doesn't contaminate crankcase oil if the engine gets up to temp.

It *can* be made from renewable feedstocks.  A lot of methanol, in particular, is made from natural gas, though, so don't get all smug about the greenness of your tank of shine until you know where it came from.

The bad:
Stoichiometric mixture is almost twice the fuel flow = need twice the volume of fuel to do the same work = MPG/GPH = about 1/2 gasoline under similar optimized circumstances.  Be sure to do your math for cost/btu versus gasoline.

Because of the above, an ideal ethanol or methanol engine isn't an ideal gasoline engine.  Different compression ratios are desirable at least.  Natural gas (= digester gas, biogas) and propane also require different-than-gasoline engine design and tuning to get their theoretical economics.

Cold starting can be a bitch.  It's why pump ethanol is usually blended with 10-25% gasoline so that something will catch fire at 20 F when the plug sparks.

Alcohol is a lousy lubricant - overly rich mixtures when cold can wash all the oil right off the int valve stem, cylinder walls...

Methanol, in particular, is quite corrosive to most metals used in gasoline fuel systems.  Both ethanol and methanol eat most rubbers used in gasoline fuel systems.  Carb seals and fuel hoses have to be specd differently.

Both methanol and ethanol are tasty to quite a few microorganisms - another good reason to blend with gasoline - it kills some of the bugs.  They also are hygroscopic, so moisture in the fuel system is a real problem.   Oh and water plus alcohol = even more bugs.

The ugly:

Alcohol's poor combustibility in a cold engine means a lot of unburned alky and partially burned alky (as Aldeydes) in exhaust of a cold engine.  Aldehydes are very carcinogenic.  Unburned alcohol in the exhaust isn't exactly good for you either.

The actual energy input/energy output ratios for ethanol are all over the map depending on which process is used, what feedstocks are used, and what is counted as a sunk cost.  Simply put:  right now, the only reason Ethanol is a viable fuel alternative for the average joe in the USA is because it's subsidized.  Yes, there are processes out there that hold the promise of lots more ethanol for lots less energy and feedstock input.  They're prototyped, but we haven't seen industrial pressure to do away with distillation (energy sink) and hydrocarbon modification processes (petroleum feedstock) yet.

Overall:

If you're making ethanol as part of some other process, you have energy to boil your mash available as a sunk cost, or your feedstock is cheap/free you might be able to do it yourself economically.  If you're buying it from somebody, it's generally not economically worth the trouble unless uncle sugar is sweetening the deal (which translates into whoring your tax money to corn farmers for votes).
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biobill

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Re: Alcohol in smaller engines
« Reply #7 on: November 21, 2006, 02:46:47 PM »
  Good info aqmxv
  I wasn't aware of the cold engine emission problem. I had always thought that alcohol burned really clean.

  I with you on the 'sustainability' of ethanol as a fuel regardless of all the hype it's getting these days. If it takes more energy to make than you can get out of it, than the big picture doesn't look good IMHO.
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6/1 Metro DI living in basement, cogen
6/1 Metro IDI running barn & biodiesel processer
VW 1.6 diesels all over the place
Isuzu Boxtruck, Ford Backhoe, all running on biodiesel
Needs diesel lawnmower & chainsaw

aqmxv

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Re: Alcohol in smaller engines
« Reply #8 on: November 22, 2006, 02:32:58 AM »
Well, Bill, you're right - alcohol does burn very cleanly.  The problem is that liquid anything doesn't burn at all.  You have to have a vapor of the stuff, and the vapor pressure of the light components of winter-blend gasoline is a lot higher than that of any alcohol.

In my tender youth in Northern Maine, it was sometimes so cold that a carbureted car wouldn't start even when it was plugged in.  The engine would turn over fine when cranked (heater on battery and freeze-plug heater).  It was so cold that even winter-blend gasoline for the NE US with full choke wouldn't vaporize enough to burn in the cylinder (this was usually when parked outside at -25 F or colder).  The solution (on our 1976 FJ44 Land Cruiser) was to undo four clips and three wingnuts (without leaving skin frozen to anything) and spritz exactly one 1/3 second shot of spray-can ether into the pipe running to the top of the carb.  Go ahead and put the air cleaner back together before starting - the ether isn't going anywhere at that temperature and it's easier when the engine's not running.

Once the engine caught on the ether, the manifold vacuum increased enough that the gasoline would vaporize and the engine would keep running.  It had to have the whiff of ether at the coldest temps to start the cycle, though.  Of course, the truck then had to run for, oh ten minutes or so to get complete enough combustion that it had sufficient torque to stir the 85W140 in the axles.  We'd generally go in and warm up for five minutes, then go back out and put the transfer case in neutral and the transmission in first.  The engine would drop 50-100 RPM when the clutch was let out.  In for another sip of hot coffee, then finally time to drive off.

Compared to what the guys with the log trucks and skidders had to do to get their stuff running after sitting in the woods all night, we had it pretty easy...

Alcohol hits that magic point of no useful vaporization at a much higher temperature.  University dons in Michigan have experimented with extremely high voltage/high amperage igniton systems to try and jolt the stuff into burning by brute force.  It works, but it's a whole lot easier (and less deadly when you get across a plug wire) just to blend a little winter-grade gasoline in for cold starting.

The other side of this is that you don't get complete combustion of alcohol until it's fully vaporizing before combustion.  That means an engine that is near normal operating temperature.  Before then, you get a lot of unburned alcohol and aldehydes in the exhaust.   If you manage to run a rich mixture, you get some of them all the time.

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Doug

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Re: Alcohol in smaller engines
« Reply #9 on: November 22, 2006, 03:00:11 AM »
Things have changed.....

My TDI Jetta starts at that with out even being plugged in lol....

Real cold is -50c you start the car in the warm garage because you knew it was going to be that cold and drive out side. Cold air hit the warm winsheild or side glass and it bursts loll.....

You call in sick because the weather chanel tells you its -50 and you didn't plug in your car lol....

Riding down the high way.....
Thump thump thump, your tyres are square from sitting on the cold ground....


Doug

aqmxv

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Re: Alcohol in smaller engines
« Reply #10 on: November 22, 2006, 03:54:19 AM »
Yes, they have changed.  VW worked very, very hard on their small diesels to make them northern-europe compatible.  It worked.  Computer-controlled high-power glow plugs get you a lot. 

Sadly, though, the vapor pressure of alchols remains stubbornly the same decade after decade.  Physics is like that.  I suppose you could try preheating the fuel injectors up to 10 C or so, but it's an underhood fire waiting to happen.

Boy do I remember the square tires!  We parked on plowed snow, and the Armstrong Norsemans we used for tires rode lumpily for most of the 12 miles of unpaved road.  They started off so square that the engine didn't have the torque to move the truck in low-range first gear until about 10 minutes of runtime had passed.
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Doug

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Re: Alcohol in smaller engines
« Reply #11 on: November 22, 2006, 05:24:57 AM »
Funny even a good set of snow tyres from then compared to now. Not quite so square these days, then again its not as cold as it used to be. I can't sleep and just stepped out for a smoke dew and dog poop all over the from lawn....
I remember as a kid I would be better than ankle deep in snow by now at least....

Boy was it cold in Timmins years ago, GM, Jag, and a few others used to do cold weather testing up there. They never used salt on the roads, it was too cold for that....

I wish it would snow, just a few inches and hide that dog poop. Air blown snow men, Christmas trees and dog poop it just looks like hell !

Doug

rmchambers

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Re: Alcohol in smaller engines
« Reply #12 on: November 22, 2006, 01:22:55 PM »
I know about cars in Maine, we lived in southern Maine and one winter it got so cold that the dashboard of my car just split down the middle.. what the hell!   It was a particularly cold night so I went out and started the car to try and get some warmth in it and make sure the battery had some charge into it before I went to bed.  You take a good deep breath and your nostrils stick together.. that's cold!

My dad used to work for an electronics outfit and they used loads of methanol to clean parts with, they could only use it a few times before it became too contaminated for electronics use so he'd take the used methanol home in the gallon jugs and we'd add a whole gallon to our gas tanks after a fill up.  We never had to worry about ice in the tank and even electronics grade methanol was probably cleaner than dry gas anyway.  I figured that was an extra gallon of fuel that cost exactly $0 so it lowered my overall fuel costs.  Did that for years, summer and winter.

Robert

phaedrus

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Re: Alcohol in smaller engines
« Reply #13 on: November 22, 2006, 08:54:26 PM »
some remarks:

Methanol metabolizes to formic acid and formaldehyde in the liver and causes necrosis there and well as neural damage, particularly of the optic nerves...  Methanol dissolved in air and aspirated at concentrations as low as 2000 ppm is toxic and accumulates, some winds up in the liver... Saturated CH30H vapor in air is within the explosive range at STP. CH3OH is transdermal - wear gloves.

Generally the same goes for the partially oxidized by-products of all alcohols.

Attempts to produce ethanol by fermentation can produce other alcohols, particularly methanol, as well.

Gasoline engines are designed with compression ratios too low to efficiently utilize alcohols as their primary fuel.

Alcohols are hydroscopic and tend to "find" their equiblirum water content. This varies, but tends to be something like 50% water.

Alcohols tend= to cause corrosion. Alcohols oxidize to acids.

I would like to see a dyno test of a listeroid diesel with 50-50 alcohol water evaporated into the intake air to saturation. For home-brew alcohol that might be the most economical use.
if ya don't ask permission they can't deny it...

Bikerbob

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Re: Alcohol in smaller engines
« Reply #14 on: December 11, 2006, 10:59:54 AM »
Well, there is a lot of knowledge ot there.
Here, in writing, just a few things to confirm what others have been writing before. This time, from real experience, real test labs etc... So this time (for a change) i know what I am writing about.  ;D

I work for a company that produces lawn and garden equipment.
I work only with the problems (after-sales and service...), or, in my twisted mind, the fun bits!


This means that I have some real life experiences, not only from one or two engines, but from about 1000 engines over the past 4 years...
We have been modifying B&S 5,5 Hp Intek engines to run on Ethanol for a few years now.
Only problem has been jetting the carb correctly. We ended up fitting an adjustable main jet, and that problem is gone.
The modification is fully our responsibility, since B&S are not willing to support this in any way.
Our risk, our customers, our warranties in other words...

Here in northern Europe, environmental concerns are high, and we always try to look into the future.
Right now, future for us is renewable fuels, spelled Ethanol.
Now, we have our own engines built (far east), ready for Ethanol straight from the factory!

Looking at our specific market, 16% of all new cars sold today is so called "flexi-fuel" cars (pump gas or E85, or any mixes in between).
Reason for this high figure is mainly lower tax, free parking in some cities etc.

Readily availible (+500 filling stations in a small country with a population of 9 million!), and cheaper than normal gas (-30%), the E85 is a success. (85% ethanol, 15% normal unleaded gas).


E85 in modern cars:
My wife is driving a Ford Focus (-02). Reasonably modern, according to my standard.
To run that car on 50% E85 is no problem what so ever. No modification, no changes in MPG. Nothing that I can measure anyway.
This is also the experience from others. Older cars (carb. engines) just need higher fuel pressure to get more fuel (10-20% into the engine.

E85 in small engines:
Ethanol is more corrosive. I have seen float bowl cups perforated, main jests plugged etc. but it is all because of one thing, and one thing only: Storage.
Ethanol will absorb water. Water will corrode just about anything...
Store the carb. DRY during winter storage (over 4 weeks storage time).

Modifications:
Two things needed to make the engine run perfect on E85.
-Raise compression. Normal lawnmower engine is typically around 8,5:1. Shoot for 10:1.

-More fuel. Approx 15-25% (by volume) is typically enough, given that you run E85. 
I know, theoretically you need 46% (by weight) more, but because of density of Ethanol, that equals 36% more by volume to reach lambda=1.
The 15-25% I refer to is however real life experience values, not theoretical. Yes, sometimes it is hard to know if the real world or the map is correct. That is when it is handy to have an engine lab...

Given that the price of E85 is (today) about 30% lower than pump gas, the main reason why people choose to run on Ethanol is because of taxes (on cars) and environmental concerns.
You cannot really save a ton of money running on E85, but it makes you sleep better at night, knowing that at least it is renewable resources...

Note: A modified small engine will not be 100% flexi-fuel, since it will be running very rich on pump-gas.
Change the main jet, and you are however back to pump gas specification again.


Starting:
The starting problem that you all are referring to is mainly because of the low compression. Run higher compression, and most of those problems will go away, since you have almost a "diesel preheating", because of the higher compression.
You also need a good ignition system.
Old B&S systems were typically a little "weak" in the start-up range compared to some of the more modern systems found today.

But honestly, I would not run Ethanol in my snowblower, or any other "critical winter machinery".
On other words, in the winter, no tests with alternative fuels in the car...
Lawnmovers are ideal test animals. Relatively cheap, simple designs and only (mainly...) used in non freezing temperatures.


Emissions, start up
Emissions are mainly unburnt Ethanol. We all know ethanol can be dangerous, especially if you drink it...
No, but seriously, since the E85 contains smaller volumes of nasty (cancerogenus) hydrocarbons, the startup emissions have been found not to be as bad as the startup emissions from gas powered engines.

Ecological?
Well, depends on how you calculate.
Some say you need more energy to produce then you will ever get out of the fuel, some say the opposite.
That is all up to you.

Oil:
Maintain your regular intervals. On a small lawnmower engine, that typically means...never...
Seriously, oil is cheap, engines are not. Your call...


/Bikerbob
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Upgrade Low-tech to Hight-tech, adding nothing but No-tech...