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ethanol in a diesel?

Posted: Fri Nov 21, 2008 9:53 am
by ocd
'been doin' some reading and came accross some stories from '80s of running compression ignition engines on blends of ethanol and castor oil, with out modification or just ethanol with some modification.

been having a hard time finding more data. figured i would toss it to the vast collective and see what comes back.

what do you know?

Posted: Fri Nov 21, 2008 11:35 am
by kassim503
The one thing I know about ethanol conversions is that you have to protect the fuel system from corrosion, b/c ethanol would rust parts out over time. Uh, also I think it requires more fuel/air. But this is all coming from a uneducated standpoint

Posted: Mon Jan 26, 2009 3:01 pm
by ocd
Here is some good info i've found so far -not from the american petroleum institute!. if anyone has corresponding data for diesel/bio diesel to add that would be great. maybe even in graph form


Molecular Weight_wide range_46.07
Carbon/Hydrogen Ratio_5.6-7.4_4.0
Optimum Air/Fuel Ratio_14.7:1_9.0:1
Tolerable Air/Fuel Ratio_13.2-15.1:1_5.3-23.3:1


Specific Gravity@ 60 degrees F_0.70-0.78_0.794
Vapor Pressure@ 100 degrees F_9.0-12.5 RVP_2.5RVP
Boiling Point F_80-440_173.3
Freezing Point F_-70_-174.6
Solubility in Water_240ppm_miscible
Viscosity @ 68 F (centipoise)_0.288_1.17
Weight per gallon(lbs)_5.8_6.59


Low Heating Value Btu/lb._18,900_11,550

High Heating Value Btu/lb._20,250_12,800
Octane Rating(Research)_90_106
Octane Pump(R+M/2)_86_98
Maximum Compression Ratio
(Spark-Ignited Engine)_8.5:1_18.5:1
Auto-Ignition Temperature F_430-500_685
Flashpoint(Closed Cup)
alcohol@200 proof F_-50_56
Flashpoint(Open Cup)
alcohol@185proof F_-45_70
Latent Heat of Vaporization@77 F

Posted: Mon Feb 09, 2009 11:34 pm
by ocd
so the 2 pieces of info we would be interested in would be the high compression ratio that ethanol can withstand and the auto ignition temperature.

here is some more data i found:

Autoignition temperature is the temperature at which a substance can be brought to flames without any sort of external force, such as a flame or spark. There are three different types of diesel fuel. These are Diesel No. 1, Diesel No. 2, and Diesel No. 4. The ignition temperature of Diesel fuel No.1 ranges from 450 to 602 Kelvin, Diesel fuel No. 2 ranges from 527 to 558 Kelvin, and Diesel fuel No .4 is 536 Kelvin.

Fuel _ Flash point _ Autoignition temperature

Ethanol_ 12.8°C (55°F) _ 365°C (689°F)
Diesel >62°C (143°F) _ 210°C (410°F)
Jet fuel >38°C (100°F) _ 210°C (410°F)
Kerosene (paraffin oil) >38–72°C (100–162°F) _ 220°C (428°F)
Vegetable oil (canola) 327°C (620°F)
Biodiesel >130°C (266°F)

Diesel flash points vary between 126°F and 204°F (52°C-96°C/WJ). Jet fuels also vary greatly. Both Jet A and jet A-1 have flash points between 100°F and 150°F (38°C-66°C/WJ), close to that of off the shelf kerosene. However, both Jet B and FP-4 have flash points between -10°F and +30°F (-23°C - -1°C/WJ)

i've been trying to figure out the actual air temp just before injection i'm sure there are some more schooled in thermodynamics than i am

i've started with PV=nrT

a 1lt cylinder and a compression ratio of 20:1 seems like an easy place to start

what do you think?

i suppose this might be usefull

[°F] = [K] × 9⁄5 − 459.67

Posted: Tue Feb 17, 2009 5:33 pm
by ocd

the reason this peaked my interest is that someone smarter than me mentioned something that made a lot of sense

"plants make a hell of a lot more sugar than they do fat"

as that relates to making ethanol versus biodiesel in a sustainable way.

-talking to old diesel mechanics i've heard about when gasoline accidentally gets put in the tank "its not that the engine blows up -it actually runs too well" the engine doesn't take a crap its the injection pump that does because of a lack of lubrication"

we know that 2% bio diesel provides adequate lubricity for the pump

i've read that in brazil in the ethanol production field they ran thier big trucks on a blend of 80% ethanol and 20% castor oil

i've read that ADM ran their trucks on strait ethanol by rigging glow plugs to run all the time and lubing the injection pump with engine oil.

i'm working on ways to produce food and fuel together so i've been doin a lot of reading and thinking.

Posted: Tue Feb 17, 2009 9:49 pm
by rlaggren
Just no chemists here, I guess. <G>

Posted: Fri Feb 20, 2009 7:28 am
by plenzen
I am no chemist just a retired grade 12 graduate. Me and Fred Flintstone were in the same class. I don’t know if going to these lighter fuels will produce as much HP as regular ol diesel. These little guys are pretty short on HP the way it is, and pretty short on technology as far as fuel delivery systems go. I always had understood that the heavier the fuel the hotter the flame. Just as the difference in E85 fuels for gassers the HP and MPGs drop somewhat because they do not produce as much energy. Winter diesel ( as it's referred to here in the GWN) does not give you the same oomph as the diesel we start getting around April/May once the stations cycle through to the summer stuff. We here ( at least where I am in Western Canada) do not have a choice of #1 or #2 or anything other than what is referred to as DIESEL FUEL.
FWIW that is my thought on it.


Posted: Fri Feb 20, 2009 6:57 pm
by ocd
thats funny the only warning i've read or heard with experementing with alcohol in a diesel is "excessive horsepower and torque" or "a runaway condition" in fact i heard from another guy who competes in tractor pulls and he actually raises the compression ratio and runs his diesel engines on ethanol/methanol

Posted: Sun Feb 22, 2009 8:48 pm
by asavage
How are you doing to inject ethanol at the right time? 'Cuz the OEM injection system sure won't hold up to it, no way.

I've had the "pleasure" of having two of my diesel vehicles filled with unleaded in Oregon when I lived there. Both times, completely toasted the injection system. The 6.2l diesel got repaired ($3200), and it ran with no apparent ill effects -- oil consumption was the same before & after the incident. It never idled as smoothly after that, but I attribute that to the quality of the IP rebuild -- took them two tries, they cracked the IP housing the first time :rolleyes:. this was the GM dealer in Salem, Capitol Chev. I drove it another 25k miles before I sold it.

The VW Rabbit did not survive, it was insurance totaled due to the cost of repairing the IP and injectors. I got it running, and mechanically it was no worse than before the incident. I sold it with the bad IP & injectors, smoking very badly.

While the majority of plants produce more sugar than fat, the fat is higher in energy-density than anything you can do with the sugar AFAIK, and algae is likely an exception to the ratio rule. I don't know about rapeseed/canola, but after oil extraction, the byproduct of soy oil is high-protein cake that is excellent for feeding cattle -- not that I'm wild about that idea either, but it does kind of shoot down the whole food-or-fuel argument.

Posted: Mon Feb 23, 2009 2:17 pm
by ocd
How are you going to inject ethanol at the right time? 'Cuz the OEM injection system sure won't hold up to it, no way.
as you experienced it wasn't the motor that was effected by the gas it was the injection pump.

but we know about biodiesel's lubricity! -i've read studies with ball scratch tests where pressures of over 6000psi have been recorded before bio diesel fails and a small scratch can be made.

-and bio does mix with ethanol . it also improves the cetane(somewhere around 8 as apposed to diesel's 45) -cetane is just an expression of the auto-ignition temp.

i have read, and seen pics, that while ethanol and diesel don't mix if you add bio they will all mix together.

(another concern would be if there is any zinc in the system any water in the fuel would probably have some effect over time.)

i was thinking a blend of ethanol and bio diesel through the stock injection system. maybe start with a 50/50 blend and possibly go up to an 80/20 blend without modification.
While the majority of plants produce more sugar than fat, the fat is higher in energy-density than anything you can do with the sugar AFAIK, and algae is likely an exception to the ratio rule. I don't know about rapeseed/canola, but after oil extraction, the byproduct of soy oil is high-protein cake that is excellent for feeding cattle -- not that I'm wild about that idea either, but it does kind of shoot down the whole food-or-fuel argument.
you are absolutely correct on the algae exception

but i think they are still working on the oil extraction methods.

i think that if you first make ethanol with the starch in the algae that the oil seperates and rises to the top then make bio and you would still have the proteins left for animal feed.

the same is true of corn ethanol production -ferment the starch(which cows don't digest anyway) the oil rises to the top and is collected and the rest is a much higher quality animal feed. its called distiller's grains and is a commodity (DDGS) traded on the stock exchange. in fact here in ptown Pacific Ethanol sells wet what they have left over for more than what they purchased the dry corn for. again shooting down the whole food vs. fuel argument.

even beter than corn is cattails grown in waste water producing 5-6k gallons of ethanol per acre just from the starch as apposed to corn with all the petroleum assistance producing only at most 450gl/acre

as far as the energy density is concerned you are right as far as it concerns Btu's.

if you had a furnace under the hood that would be important.

but we are looking for other qualities in a fuel such as kinematic energy -how much work it produces not how much heat it produces

-and flame front speed -when it produces that work

-and how clean it burns -sulfur, heavy metals, HC, NOx, CO could all be reduced drastically with alcohol.

all this is just thinking i will always defer to experience -and any experimentation should probably be done in a shop with a dyno and a knock sensor/meter to avoid damage.

but during the '80s mercedes-benz did produce diesel buses running on straight alcohol by routing an extra lube oil line from the engine with appropriate filtration of course into the injection pump and a return line for excess oil.

but probably with a cetane improver and at least 1% biodiesel the extra lube could be eliminated.

volvo avoided the extra lube by using a dual injection system that first injects 20% diesel to get a good hot burn and then slightly after injecting alcohol (with as much as 50% water!) through a seperate injector loosing lest than 10% power. at low loads and idle they only injected diesel.

obviously this isn't an economically viable solution for retrofitting but it does provide some applicable data.

another option would be fumigation through the air intake after turning the ip down to only deliver maybe half -made easy by the throttle body on the SDxx. i figured someone would have some experience with some kit that was available in the '80's :) i'm sure it would be similar to injecting propane or natural gas systems rapidly spreading through city bus companies. -since they are also high-octane/low-cetane fuels -

of course again a dyno would be useful in determining the optimum tuning.

i can imagine if just using the stock ip system and blending fuels the difference in viscosity with ethanol that more fuel would get through the injector at a given pressure though the increase in HP and torque might be worth the small increase in fuel usage . :)

again i know i'm young and inexperienced and will always defer to real world data i just read stuff and think a lot :oops:

more data

Posted: Tue Oct 27, 2009 12:27 pm
by ocd
here is some more data on ignition delay for alcohol/D2 blends:

Ignition Delay Correlations for Neat Ethanol and Ethanol-Df2 Blends in a D.I. Diesel Engine
Document Number: 841343
Date Published: October 1984
Mohamed N. Saeed - Dept. of Mechanical Engineering, Alexandria University, Egyp
Naeim A. Henein - Wayne State Univ.
A study was conducted on a direct-injection, single-cylinder, research-type diesel engine to determine the effect of adding ethanol to diesel fuel on the ignition delay period. The tests covered the whole range of ethanol-DF2 blends: from 100% ethanol to 100% DF2.

The test parameters were:

-ethanol content,
-intake-air properties,
-equivalence ratio.

The ignition delay was measured by detecting the beginning of injection and the occurrence of a detectable pressure rise.

The present results show that, for ethanol-DF2 blends,
the pressure-rise delay decreases by increasing both the intake-air pressure and the intake-air temperature,
and increases by increasing the ethanol content in the blend.
Ignition delay correlations were developed in terms of air temperature, air pressure, and ethanol volumetric fraction. The global activation energy was determined and correlated with the cetane number for each blend.
File Size: 2051K

Fuelling of a compression ignition engine on ethanol with DME as ignition promoter: Effect of injector configuration
D. Cipolat , a, and N. Bhanaa
aSchool of Mechanical Engineering, University of the Witwatersrand, Johannesburg, South Africa

Received 13 November 2008;
revised 14 April 2009;
accepted 1 May 2009.
Available online 3 June 2009.

The effect of injector configuration on the combustion and emissions of a compression ignition engine, fuelled on ethanol as the main fuel and dimethyl ether as ignition promoter, were investigated. Baseline constant speed tests were initially performed on diesel fuel using the recommended three-hole configuration. The tests were repeated with the recommended three-hole injector and then with a four-hole injector with ethanol as the main fuel. All other aspects of the engine remained unmodified. The four-hole injector resulted in the combustion of ethanol occurring closer to top dead centre, producing marginally more power and higher fuel conversion efficiency. In the case of the four-hole injector, emissions of both THC and NOX were found to be lower than those produced by the three-hole injector. They were, however, in both cases lower than levels achieved with diesel fuelling.

Keywords: Combustion; Rate of energy release; Emissions; Injector configuration

Abbreviations: BTDC, Before Top-Dead Centre; ABDC, After Bottom-Dead Centre; BBDC, Before Bottom-Dead Centre; ATDC, After Top-Dead Centre; DME, Dimethyl Ether; °CA, Degree Crank Angle; CI, Compression Ignition; SI, Spark Ignition; NOX, Nitrogen Oxides; THC, Total (unburned) Hydrocarbons