Transcript ALCOHOL AS AN ALTERNATIVE FUEL IN I.C ENGINES


INTRODUCTION
In this century, it is believed that crude oil and petroleum products will
become very scarce and costly.
 Day-to-day, fuel economy of engines is getting improved and will
continue to improve. However, enormous increase in number of


vehicles has started dictating the demand for fuel.
With increased use and depletion of fossil fuels, alternative fuel
technology will become more common in the coming decades.
Because of the high cost of petroleum products, energy security ,
emission problems some developing countries are trying to use alternate
fuels for their vehicles.
Escalating Prices
Of Crude Oil
Anthropogenic Global Warming
History and Future
Future Global
Warming
Normal
Interglacial
Plunge into
next ice Age.
Modern
Global
Warming
“Neolithic
global
warming”.
Why is Global Warming Bad?
Neolithic
Global
Warming
Future Global Warming
Modern
Global
Warming
Plunge
into ice
Age.
The fast rise in
temperature may trigger
the next major ice sooner
than it would otherwise
occur, due to switching
off Atlantic Ocean
currents.
• Rapid changes in temperature cause agriculture possibilities to switch from one area
of the world to another. Thus, many people will die due to lack of food.
• Rapid increases in temperature cause more severe weather to occur, such as
hurricanes. Thus, many people will die (have already died!).
• Rapid increases in temperature cause the glacial ice at the North and South Poles to
melt, raising sea levels; which will flood many major cities of the world.

LIQUID FUELS:
Liquid fuels are preferred for IC engines because they are
easy to store and have reasonably good calorific value.
The main alternative is the alcohol

ALCOHOL:
Alcohols are attractive alternate fuels because they can
be obtained from both natural and manufactured
sources. Methanol and ethanol are two kinds of alcohols
that seem most promising.
What about Using Ethanol and/or Biodiesel for Fuel?
Farmers must use biofuels to produce
biofuels, not petro fuels!
Closed carbon dioxide greenhouse gas cycle for biofuels.
Ethanol & biodiesel are sustainable forms of solar energy.
Structure of ethanol molecule.
Glucose (a simple sugar) is created in
the plant by photosynthesis.
6 CO2 + 6 H2O + light → C6H12O6 + 6 O2
During ethanol fermentation, glucose is
CH3CH2OH
All bonds are single decomposed into ethanol and carbon dioxide.
bonds
C6H12O6 → 2 CH3CH2OH+ 2 CO2 + heat
During combustion ethanol reacts with oxygen to produce carbon
dioxide, water, and heat:
CH3CH2OH + 3 O2 → 2 CO2 + 3 H2O + heat
Ethanol
 HOW IS IT MADE NOW?
 HISTORICALLY MADE FROM CORN AND OTHER
STARCH SOURCES OR FROM NATURAL SUGARS BY
FERMENTATION
 COMMON SOURCES INCLUDE RICE, POTATO,
CASSAVA – PLUS CORN AND OTHER GRAINS
 MANUFACTURING PROCESS WAS VERY ENERGY-
INTENSIVE, BUT IS NOW LESS SO IN MOST
MODERN PLANTS, DUE TO ADVANCES IN
DISTILLATION TECHNOLOGY
co2
CORN
STARCH
DRY MILL
‘DRY’ FUEL
ETHANOL
PRODUCT
CORN
ENZYMATIC
HYDROLYSER
SYRUP
FERMENTER
STILL
DEHYDRATOR
HEAT
Michael Wang – Argonne National Laboratory, Aug. 2005
Energy Input ratio = input for EtOH / input for gasoline = .74/1.23 = 0.6 :
1
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Some Properties of Methanol, Gasoline and Diesel Fuel
Mass and Energy Balance
Summary of mass
balance
Out of 87730kg. Of sugar beet
Plants we get
3775kg.(4775 l) Of EtOH
38990kg. Of tops & leaves
2760kg of beet pulp
1220kg. Of undecanted stillage
Remaining water by
subtraction
FUEL FOR FARM
OPERATIONS
(VERY SMALL)
FERTILIZER
(VERY SMALL)
NATURAL ENERGY
INPUTS
(VERY LARGE)
THE FARMING OPERATION TAKES ALL
ANTHROPOMORPHIC AND NATURAL
ENERGY INPUTS AND CONVERTS THEM
INTO ENERGY CONTAINED IN A CROP. THIS
CROP MAY BE BIOMASS OF ALMOST ANY
KIND OR, MORE NARROWLY, MAY BE CORN,
AN OILSEED CROP SUCH AS SOYBEAN OR
RAPESEED OR A FOOD CROP PLUS A CROP
RESIDUE USED FOR CONVERSION INTO
ENERGY
FARM PRODUCT(S) :
TREAT AS
FEEDSTOCK FOR
CONVERSION
PROCESS
FARM ▲
REFINERY
PROCESS HEAT
(TYPICALLY FOSSIL
FUEL)
ELECTRICAL POWER
FOR PUMPS, ETC.
FARM PRODUCT(S)
(ADD: TRANSPORTATION AND
HANDLING ENERGY)
THE ENERGY CONVERSION OPERATION
EXTRACTS COMPONENTS HAVING AN
ENERGY VALUE FROM THE CROP BY
PHYSICAL, CHEMICAL AND/OR
BIOCHEMICAL PROCESSING. THE
REQUIRED PROCESS ENERGY INPUTS MAY
BE DERIVED DIRECTLY OR INDIRECTLY
FROM THE FARM PRODUCTS OR BY
BURNING FOSSIL FUELS. BY-PRODUCTS
MAY OR MAY NOT BE INCLUDED IN THE
ENERGY BALANCE DEPENDING ON THEIR
USE.
OTHER INPUTS AS
RELEVANT:
CHEMICALS
WATER
STEAM
NET ENERGY PRODUCT
ADD: TRANSPORTATION,
BLENDING AND DISTRIBUTION,
ENERGY USE
NON-ENERGY
BYPRODUCTS
(QUANTIFY BUT
EXCLUDE):
E.G., UNUSED
WASTE,
ANIMAL FOOD
Energy balance calculation
Energy received from sunlight (GJ/ha)
245.7
[(i) Energy content of sugar beet]
[(ii) By products ,tops & leaves
167.2
78.5
Energy invested at farm
31.3
Energy invested in building EtOH plant
2.4
So, total energy invested
33.7
By products, tops & leaves left at farm{as fertilizers }
11.0
NET INVESTED ENERGY AT FARM
22.7
ENERGY OBTAINED
FROM
EtOH
101.8
FROM
By-products Bio-Gas
14.7
FROM
Beet Pulp
32.3
FROM
Stillage
18.7
Energy invested at Industry in producing EtOH
{Let this energy be equivalent to energy received from by
products}
SO,NET ENERGY OBTAINED =
64.1
[101.8 – 22.7] GJ/ha = 79.1
Energy Balances of biomass Fuels
BIOMASS TO ETHANOL
 AN INTEGRATED, FULL-SCALE COMMERCIAL
BIOPROCESS PLANT CONSISTS OF FIVE BASIC UNIT
OPERATIONS






1. FEEDSTOCK PREPARATION;
2. DECRYSTALLIZATION/HYDROLYSIS REACTION
VESSEL;
3. SOLIDS/LIQUID FILTRATION;
4. SEPARATION OF THE ACID AND SUGARS;
5. FERMENTATION OF THE SUGARS; AND,
6. PRODUCT PURIFICATION.
BIOMASS TO ETHANOL (1)
ABENGOA (AND OTHERS)
BIOMASS TO ETHANOL (1)
ABENGOA (AND OTHERS)
BIOMASS TO ETHANOL ABENGOA
 PROPOSED PLANT IN KANSAS
 www.abengoabioenergy.com/research/index.cfm?page=7
 RAW MATERIAL INPUT:
 700 TONS/DAY (210,000 TONS/YR*) CORN STOVER, WHEAT
STRAW, MILO STUBBLE, SWITCHGRASS, ETC.
 PLANT WILL PRODUCE:
 11.4 MILLION GALLONS OF ETOH/YR
 ENOUGH ENERGY TO POWER THE FACILITY
 EXCESS ENERGY WILL BE USED TO POWER ADJACENT CORN
DRY GRIND MILL
BIOMASS TO ETHANOL (2)
ALICO/BRI (COSKATA IS SIMILAR)
BIOMASS TO ETHANOL (2)
ALICO/BRI (COSKATA IS SIMILAR)
 PROPOSED PLANT IN LABELLE, FLORIDA
 www.brienergy.com/pages/process01.html
 RAW MATERIAL INPUT:
 770 TONS/DAY (231,000 TONS/YR*) YARD, WOOD, &
VEGETATIVE WASTES
 PLANT WILL PRODUCE (ASSUMING 24 HR/DAY, 300
DAY/YR):
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
13.9 MILLION GALLONS OF ETOH/YR
6,255 KW OF ELECTRIC POWER (~45 GWH/YR*)
8.8 TONS H2/DAY (2,640 TONS H2 /YR*)
50 TONS AMMONIA/DAY (15,000 TONS AMMONIA/YR* )
A 10-Step
Overview
Conversion of Cellulose/Hemicellulose to Mixed Sugars
Using Patented Arkenol Process Technology of
Concentrated Acid Hydrolysis
Simplified Flow Diagram
2
Acid
Reconcentration
Concentrated
7
Sulfuric Acid
Strong
Sulfuric Acid
4
1st stage
Hydrolysis
1
Condensate
Return
Filter
Biomass
Steam
2nd stage
Solids
Hydrolysis
Steam
Filter
5
Solids
Pump
3
Lignin
Steam
Acid/Sugar
to silica
processing
(as required)
Solution
Acid Recovery
Water
Lime
Liquor
Purified
6
Centrifuge
Sugar Solution
9
Mixed Sugars to
Fermentation or
Direct conversion
- Hydrogenation
- Thermal conversion
10
Chromatographic
Separation
Mixing
Tank
8
Solids
Gypsum
http://www.luefireethanol.com/
BlueFire Ethanol, Inc.
 PROPOSED PLANT IN SOUTHERN CALIFORNIA
 RAW MATERIAL INPUT:
 700 TONS/DAY (210,000 TONS/YR*) OF SORTED GREEN WASTE
AND WOOD WASTE FROM LANDFILLS
 PLANT WILL PRODUCE:
 19 MILLION GALLONS OF ETOH/YR
 TECHNOLOGY:
 ARKENOL CONCLUDED THAT CONCENTRATED ACID
HYDROLYSIS WAS THE ONLY PROCESS ECONOMICALLY
VIABLE AND CAPABLE OF PROCESSING ANY CELLULOSE
WASTES
 ARKENOL AND AFFILIATES HAVE MUCH EXPERIENCE
*based on a 300 day year
•Cellulosic
BROIN COMPANIES
 PROPOSED PLANT IN EMMETSBURG (PALO ALTO
COUNTY), IOWA
 RAW MATERIAL INPUT:
 842 TONS/DAY (252,600 TONS/YR*) OF CORN
FIBER, COBS AND STALKS
 PLANT WILL PRODUCE:
 125 MILLION GALLONS OF ETOH/YR (25% OF
THEM ARE CELLULOSIC ETHANOL)
 TECHNOLOGY:
 BROIN FRACTIONATION, ALSO TRADEMARKED
BFRAC™.
*based on a 300 day year
BFRAC™
 THIS NEW BIO-REFINING TECHNOLOGY
SEPARATES THE CORN INTO THREE
FRACTIONS INCLUDING FIBER, GERM AND
ENDOSPERM.
 THE ENDOSPERM IS THEN FERMENTED TO
CREATE ETHANOL, WHILE THE REMAINING
FRACTIONS ARE CONVERTED INTO NEW
VALUE-ADDED CO-PRODUCTS, INCLUDING
DAKOTA GOLD HP™, DAKOTA BRAN™ CAKE,
CORN GERM MEAL, AND CORN OIL.
 IN ADDITION TO THESE HIGH VALUE COPRODUCTS, THE PROCESS ALSO RESULTS IN
INCREASED ETHANOL YIELDS AND DECREASED
ENERGY CONSUMPTION.
IOGEN BIOREFINERY PARTNERS, LLC
 PROPOSED PLANT IN SHELLEY, IDAHO
 RAW MATERIAL INPUT:
 700 TONS/DAY (210,000 TONS/YR) AGRICULTURAL RESIDUES
INCLUDING WHEAT STRAW, BARLEY STRAW, CORN STOVER,
SWITCHGRASS, AND RICE STRAW AS FEEDSTOCKS
 PLANT WILL PRODUCE:
 18 MILLION GALLONS OF ETOH/YR
 TECHNOLOGY - TRADITIONAL ENZYME FERMENTATION
PRODUCTION
 [1]Iogen Corp, “CELLULOSE ETHANOL: Clean Fuel for Today and Tomorrow”
 [2]http://www.tc.gc.ca/programs/Environment/climatechange/docs/biomass
/Image4.gif
 [3] Iogen Ethanol process:
http://www.gmcanada.com/inm/gmcanada/english/about/MissionGreen/Da
ily/Sep20.html
*based on a 300 day year
IOGEN’S PATENTED ETHANOL PROCESS
[1]
[2]
#1
#2
#5
#3
#4
#1
#2
#3
#4
#5
#6
#7
#8
#6
#7
#8
Block Diagram of 8 stage Process [2]
Products of 8 stage Process [2]
Assuming 320 of EtOH L/dry ton
Yields approximately 17.75 Mgal EtOH
Block Diagram of 8 stage Process [1]
RANGE FUEL’S PATENTED ETHANOL
PROCESS
• PROXIMITY TO BIOMASS FEEDSTOCK AND ETHANOL
MARKETS
• RAIL AND ROAD ACCESS
• WATER, POWER, GAS, AND SEWER AVAILABILITY.
• OPTIMAL FEEDSTOCK DRAW ( 45MI AND 75 MI RADII)
[1] “Vinod Khosla,”Mostly convenient truths”
RANGE FUELS
 PROPOSED PLANT IN SOPERTON, GEORGIA
 RAW MATERIAL INPUT:
 1200 TONS/DAY (360,000 TONS/YR*) WOOD RESIDUES
AND WOOD BASED ENERGY CROPS.
 PLANT WILL PRODUCE:
 40 MILLION GALLONS OF ETHANOL/YEAR
 9 MILLION GALLONS OF METHANOL/YEAR
 TECHNOLOGY
 THERMO-CHEMICAL CONVERSION PROCESS
(THE “K2 SYSTEM”)


CONVERT BIOMASS TO A SYNTHETIC GAS
CONVERT THE GAS TO ETHANOL.
*based on a 300 day year
RANGE FUEL’S PATENTED ETHANOL PROCESS RATIONALE
 FERMENTATION AND ACID HYDROLYSIS CAN TAKE DAYS TO

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


OCCUR, BUT THERMAL CONVERSION BREAKS DOWN ORGANIC
MATTER AND CONVERTS IT TO ETHANOL IN MINUTES.
THE PROCESS USES LITTLE ENERGY TO START; IT FUELS ITSELF IN A
SELF-SUSTAINING FASHION; IT PRODUCES VIRTUALLY NO WASTE
PRODUCTS; IT EMITS VERY LOW LEVELS OF GREENHOUSE GAS.
RANGE FUELS CLAIMS IT CAN PRODUCE MORE ETHANOL FOR A
GIVEN AMOUNT OF ENERGY EXPENDED THAN IS POSSIBLE WITH
ANY OTHER COMPETING PROCESS.
DEPENDING UPON THE QUANTITY AND AVAILABILITY OF
FEEDSTOCK, THE K2 SYSTEM CAN SCALE FROM ENTRY-LEVEL
SYSTEMS TO LARGE CONFIGURATIONS.
THIS RANGE OF SYSTEM PERFORMANCE WILL ALLOW THE K2 TO
BE PLACED NEAR THE BIOMASS LOCATION REDUCING
TRANSPORTATION COSTS, AND WILL ALLOW THE MOST
ECONOMICAL SIZE SYSTEM TO BE DEPLOYED.
SINCE THE SYSTEM IS MODULAR, ADDING ANOTHER MODULE –
WHICH IS EASY TO SHIP AND INSTALL, INCREASES THE OUTPUT.
[1] “Another Cellulosic Ethanol Plant Announced “, http://thefraserdomain.typepad.com/energy/2007/02/another_cellulo.html
Properties of Ethanol, Methanol, Gasoline and Diesel
Fuel
Blending
1]
Automobile fuels be “oxygenated” in order to reduce air
pollution. Since alcohols contain oxygen, interest in ethanol
as an oxygenate.
2]In addition, removal of lead from gasoline renewed
interest in ethanol as octane booster. There are alternatives
to ethanol for both of these needs. The oil industry originally
pushed MTBE as an oxygenate, but it was phased out after
discovery that it was causing water pollution problems.
3] While E10/E15 is intended for all automobiles, a blend
called “E85” is intended for flex fuel vehicles. E85 is
nominally 85% ethanol and 15% gasoline, albeit it can be as
high as 30% gasoline in cold climates in winter. The principle
reason for blending some gasoline into ethanol for flex fuel
vehicles is to improve starting in cold weather.
4] above, ethanol is separated from the water in which it is
produced via a process called distillation. The distillation
process does not remove all of the water. Having some water
mixed in with the fuel is actually improves performance of an
internal combustion engine, as the water provides extra mass
to absorb the heat of combustion and turn it into high
pressure steam for mechanical energy.
5] ethanol as low as 160 proof (80% ethanol, 20% water)
works very well in automobile engines designed to run on
alcohol.
6] However, water and gasoline don’t mix well (are not
“miscible”, in chemical terms), so
the water must be removed when producing ethanol-gasoline
blends. This dry or “anhydrous” ethanol is needed to prevent
phase separation of the fuel components in ethanol - gasoline
blends.
Power Making Fuel
Characteristics
1.Octane
Rating [MON]
2.Burning
Rate
1. Octane
Rating
3.Latent
HeatRate
of Vaporization
2. Burning
[kJ/kg
]
3.
Latent
Heat of Vaporization
4.Energy
Value
[MJ/kg]
4. Energy
Value
&
5.Reduction in Green house
gases
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1. Octane


Measures fuel’s resistance to preignition and detonation, commonly
called “knocking”
Three common octane ratings for
motor fuels:
Research Octane Number (RON)
 Motor Octane Number (MON)
 (R+M/2) method

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1. Octane (cotd.)



MON rating is most useful to racers
because it is measured under high
loads and at high RPM’s
High MON rated fuels allow the use of
higher compression and advanced
spark timing
E85 delivers MON octane ratings
equal to, or better than, most
gasoline
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2. Burning Rate



The speed at which fuel burns and releases
its heat energy
There is less time for fuel to burn at high
RPM’s, so rapid burning fuel is a must in
racing
Peak horsepower (kW) and engine
efficiency are realized if fuel is almost
completely burned by 20 degrees after Top
Dead Center (TDC)
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3. Latent Heat of Vaporization



Measures a fuel’s ability to cool the
intake charge and combustion chamber
Measured in kJ/ lt.
Higher rated fuels remove heat better
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3. Latent Heat of Vaporization
E85 promotes better cooling:
 Making the intake charge more dense,
thereby packing more energy (per
volume) into the engine
 Helping to control detonation
 Reducing temperatures in the engine
and oiling system components
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4. Energy Value



The total heat energy contained in a given
amount of fuel – kJ/kg
Horsepower generation depends on “Net
Energy Value” - Equal to the energy value
multiplied by the amount of fuel that can be
burned
A fuel’s “stoichiometric” defines its ideal
air/fuel ratio
Lower stoichiometric fuels allow more fuel to
be burned which, in turn, increases the Net
Energy Value of the fuel
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
A fuel’s “stoichiometric” defines its ideal air/fuel ratio
Lower stoichiometric fuels allow more fuel to be
burned which, in turn, increases the Net Energy
Value of the fuel
 The lower stoichiometric of E85 provides the fuel
with a higher Net Energy Value than most gasoline

“Ethanol Blends Significantly Reduce Greenhouse Gas Emissions”
Argonne National Labs.
Reduction in GHG
0%
-2%
-2%
-6%
-20%
-17%
-23%
-40%
-60%
-64%
-80%
E10 GV: DM
Corn EtOH
E10 GV: WM E10 GV: Cell. E85 FFV: DM E85 FFV: WM
Corn EtOH
EtOH
Corn EtOH
Corn EtOH
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E85 FFV:
Cell. EtOH
Fuel Comparison Chart
Fuel
Octane
(MON)
Burning Rate
(ms@stoic.)
Latent Heat
(BTU/gal)
Energy
Value
BTU/lbs
Power
Stoic.
Net Energy
Value
(MJ/kg)
Pure
Ethanol
102
.39
396
12,800
6.5/1
3.00
Pure
Methanol
103
.43
503
9,750
5/1
3.08
Pump
Gasoline
80-90
.34
150
(avg.)
18,70019,100
12.5/1
2.92
Racing
Gasoline
99
N/A
160
(est.)
18,500
(est.)
12.5/1
2.90
E30
87-94
.36
337
17,178
10.7/1
2.94
E85
99-100
.38
359
14,021
7.4/1
2.99
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Fuel Rankings
Fuel
Octane
(MON)
Burning Rate
(ms@stoic.)
Latent Heat
(BTU/gal)
Net Energy
Value
(MJ/kg)
Pure
Ethanol
2
5
2
2
Pure
Methanol
1
6
1
1
Pump
Gasoline
6
2
6
5
Racing
Gasoline
4
1
5
6
E30
5
3
4
4
E85
3
4
3
3
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
DIFFICULTIES:
1. Extensive research and development is difficult to
justify until the fuels are accepted as viable for large
numbers of engines.

2. Most alternate fuels are very costly at present since
the quantity used is very less.

3. There is lack of distribution points (service stations)
where fuel is available to the public.
BRAZIL
World leader in production and export of ethanol.
Ethanol produced per day equivalent to 200,000 barrels of
gasoline.
24% blend ethanol mandatory.
Competitiveness
Bio diesel initiatives underway
U.S.A.
Ethanol : a big boost to economy
E85 sells cheaper than gasoline
Currently production aimed at 4.5 Billion
gallons/yr
India
Sources of ethanol:
Sugarcane
Molasses
Agricultural waste
Low average cost of Rs.18/litre projected
Annual production capacity of 1.5 Billion litres
Alcohol fuel conversion apparatus
for internal combustion engines
 Alcohol fuel conversion apparatus for internal combustion




engines including a fuel tank, a fuel pump, a primary heat
exchanger, a heat source, a converter and a carburetor.
The pump delivers pressurized liquid alcohol to the primary
heat exchanger where the alcohol fuel is heated above the
vaporization point at ambient pressure.
The heated fuel is next delivered to the converter where the
super-heated liquid alcohol is vaporized at reduced pressure.
The alcohol is then delivered to the carburetor where the
vaporized alcohol is metered and mixed with air for proper
combustion.
The air-fuel mixture, in gaseous form is then delivered to the
intake system of a conventional internal combustion engine.
A fuel pre-heater assembly utilizing waste heat from the
engine may also be provided.

ADVANTAGES:
1. It is a high octane fuel with anti-knock index numbers
of over 100.Engines using high octane fuel can run more
efficiently by using higher compression ratios. Alcohols
have higher flame speed.
2. It produces less overall emissions compared to
gasoline.
3. When alcohols are burned, it forms more moles of
exhaust gases, which gives higher pressure and more
power in the expansion stroke.
4. It has high latent heat of vaporization which results
in a cooler intake process. This raises the volumetric
efficiency of the engine and reduces the required work
input in the compression stroke.
5. Alcohols have low sulphur content in the fuel.
6. Reduced petroleum imports and transportation.

DISADVANTAGES:
1. Alcohols have low energy content or in other words the calorific value of
the fuel is almost half. This means that almost twice as much as gasoline
must be burned to give the same energy input to the engine.
 With equal thermal efficiency and similar engine output usage, twice as
much fuel would have to be purchased, and he distance which could be
driven with a given fuel tank volume would be cut in half. Automobiles as
well as distribution stations would require twice as much storage capacity,
twice the number of storage facilities, twice the volume of storage at the
service stations, twice as many tank trucks and pipelines, etc.
 Even with the low energy content of the fuel, engine power for a given
displacement would be about the same. This is because of the lower airfuel ratio needed by alcohol. Alcohol contains oxygen and thus requires
less air for stoichiometric combustion. More fuel can be burned with the
same amount of air.
2. Combustion of alcohols produces more aldehydes in the exhaust. If as
much alcohol fuel was consumed as gasoline. Aldehyde emissions would
be a serious problem.
 3. Alcohol is much more corrosive than gasoline on copper,
brass, aluminum, rubber, and many plastics. This puts
some restrictions on the design and manufacturing of
engines to be used with this fuel. Fuel lines and tanks,
gaskets, and even metal engine parts can deteriorate with
long-term alcohol use (resulting in cracked fuel lines, the
need for special fuel tank, etc). Methanol is very corrosive
on metals.
4. It has poor cold weather starting characteristics due to
low vapor pressure and evaporation. Alcohol-fuelled
engines generally have difficulty in starting at temperatures
below 10 C. Often a small amount of gasoline is added to
alcohol fuel, which greatly improves cold-weather starting.
However, the need to do this greatly reduces the
attractiveness of alcohol.
5. Alcohols have poor ignition characteristics n general.
 6. Alcohols have an almost invisible flame, which is
considered dangerous when handling fuel. A small
amount of gasoline removes this danger.
7. There is the danger of storage tank flammability,
due to low vapor pressure. Air can leak into storage
tanks and create combustible mixtures.
8. There will be less NOx emissions because of low
flame temperatures. However, the resulting lower
exhaust temperatures take longer time to heat the
catalytic converter to efficient operating temperatures.
9. Many people find the strong odor of alcohol very
offensive. Headaches and drizzles have been
experienced when refueling an automobile.
10. There is a possibility of vapor lock in fuel delivery
systems

METHANOL:
Of all the fuels being considered as an alternate to gasoline,
methanol is one of the most promising and has
experienced major research and development. Pure
methanol and mixtures of methanol and gasoline in
various percentages have been extensively tested in engines
and vehicles for a number of years. The most common
mixtures are M85 (85% methanol and 15% gasoline). The
data of these tests which include performance and
emission level levels are compared with pure gasoline (M0)
and pure methanol (M100). Some smart flexible fuel (or
variable fuel) engines are capable of using any random
mixture combination of methanol and gasoline ranging
from methanol to pure gasoline. Two fuel tanks are used
and various flow rates of the two fuels can be pumped to
the engine, passing through a mixing chamber. Using
information from sensors in the intake and exhaust, the
electronic monitoring systems (EMS) adjust to the proper
air-fuel ratio, ignition ratio, ignition timing, injection
timing, and valve timing (where possible) for the fuel
mixture being used.
 Methanol can be obtained from many sources, both fossil
and renewable. These include coal, petroleum, natural gas,
biomass, wood, landfills, and even the ocean. However, any
source that requires extensive manufacturing or processing
raises the price of the fuel.
Emissions from an engine using M10 fuel are about the
same as those using gasoline. The advantage (and
disadvantage) of using this fuel is mainly 10% decrease in
HC and CO exhaust emissions. However, there is an
increase in NOx and a large (500%) increase in
formaldehyde emissions.
Methanol is used some dual-fuel CI engines. Methanol by
itself is not a good CI engine fuel because of its high octane
number, but if a small amount of diesel oil is used for
ignition, it can be used with good results. This is very
attractive for developing countries, because methanol can
often be obtained from much cheaper source than diesel
oil. Methanol fuel has received less attention than ethanol
fuel as an alternative to petroleum based fuels.
 Use
Methanol fuel is also used extensively in drag racing, primarily in
the Top Alcohol category.
Formula One racing continues to use gasoline as its fuel, but in pre
war grand prix racing methanol was often used in the fuel.
Use as internal combustion engine fuel
Both methanol and ethanol burn at lower temperatures than
gasoline, and both are less volatile, making engine starting in cold
weather more difficult. Using methanol as a fuel in spark ignition
engines can offer an increased thermal efficiency and increased
power output (as compared to gasoline) due to its high octane
rating (114) and high heat of vaporisation. However, its low energy
content of 19.7 MJ/kg and stoichiometric air fuel ratio of 6.42:1
mean that fuel consumption (on volume or mass basis) will be
higher than hydrocarbon fuels. The extra water produced also
makes the charge rather wet (similar to hydrogen/oxygen
combustion engines)and combined with the formation of acidic
products during combustion, the wearing of valves, valve seats and
cylinder might be higher than with hydrocarbon burning. Certain
additives may be added to motor oil in order to neutralize these
acids.
 Methanol, just like ethanol, contains soluble and insoluble
contaminants. These soluble contaminants, halide ions
such as chloride ions, have a large effect on the corrosivity
of alcohol fuels. Halide ions increase corrosion in two ways;
they chemically attack passivating oxide films on several
metals causing pitting corrosion, and they increase the
conductivity of the fuel. Increased electrical conductivity
promotes electric, galvanic, and ordinary corrosion in the
fuel system. Soluble contaminants, such as aluminium
hydroxide, itself a product of corrosion by halide ions, clog
the fuel system over time.
Methanol is hygroscopic, meaning it will absorb water
vapor directly from the atmosphere. Because absorbed
water dilutes the fuel value of the methanol (although, it
suppresses engine knock), and may cause phase separation
of methanol-gasoline blends, containers of methanol fuels
must be kept tightly sealed.
 Toxicity
 Methanol is poisonous; ingestion of only 10 ml can
cause blindness and 60-100 ml can be fatal, and it
doesn't have to be swallowed to be dangerous since the
liquid can be absorbed through the skin, and the
vapors through the lungs. US maximum allowed
exposure in air (40 h/week) is 1900 mg/m³ for ethanol,
900 mg/m³ for gasoline, and 1260 mg/m³ for
methanol. However, it is less volatile than gasoline,
and therefore decreases evaporative emissions. Use of
methanol, like ethanol, significantly reduces the
emissions of certain hydrocarbon-related toxins such
as benzene and 1, 3 butadiene. But as gasoline and
ethanol are already quite toxic, safety protocol is the
same.
 Safety
Since methanol vapour is heavier than air, it will linger
close to the ground or in a pit unless there is good
ventilation, and if the concentration of methanol is
above 6.7% in air it can be lit by a spark, and will
explode above 54 F / 12 C. Once ablaze, the flames give
out very little light making it very hard to see the fire
or even estimate its size, especially in bright daylight.
If you are unlucky enough to be exposed to the
poisonous substance through your respiratory system,
its pungent odor should give you some warning of its
presence. However, it is difficult to smell methanol in
the air at less than 2,000 ppm (0.2%), and it can be
dangerous even at lower concentrations
E85,alcohol fuel mixture of 85% ethanol and 15%
gasoline
 E85 is an alcohol fuel mixture of 85% ethanol and 15% gasoline, by volume. ethanol
derived from crops (bioethanol) is a biofuel.
E85 as a fuel is widely used in Sweden and is becoming increasingly common in the
United States, mainly in the Midwest where corn is a major crop and is the primary
source material for ethanol fuel production.
E85 is usually used in engines modified to accept higher concentrations of ethanol.
Such flexible-fuel engines are designed to run on any mixture of gasoline or
ethanol with up to 85% ethanol by volume. The primary differences from non-FFVs
is the elimination of bare magnesium, aluminum, and rubber parts in the fuel
system, the use of fuel pumps capable of operating with electrically-conductive
(ethanol) instead of non-conducting dielectric (gasoline) fuel, specially-coated
wear-resistant engine parts, fuel injection control systems having a wider range of
pulse widths (for injecting approximately 30% more fuel), the selection of stainless
steel fuel lines (sometimes lined with plastic), the selection of stainless steel fuel
tanks in place of terne fuel tanks, and, in some cases, the use of acid-neutralizing
motor oil. For vehicles with fuel-tank mounted fuel pumps, additional differences
to prevent arcing, as well as flame arrestors positioned in the tank's fill pipe, are
also sometimes used..
Ethanol and Flexible Fuel Vehicles (FFVs)
What is a FFV?
• FFVs are specially designed to run on all ethanol blends up to 85%
• FFVs can use any mixture of gasoline or E85
• FFVs observe a mileage reduction
on E85 vs. gasoline
• FFVs have fuel sensors which
monitor ethanol/gasoline ratios
All Gasoline
% Mixture
All E85
Ethanol & E85 vs. Gasoline
Property
Ethanol
Gasoline (87 Octane)
E85
Octane (R+M)/2
98-100
86-94
96
Lower Heating Value(Btu/lb)
11,500
18,000-19,000
12,500
Gallon Equivalent
1.5
1
1.4
Miles per Gallon vs. Gasoline
70%
100%
72%
Tank is 1.5 times
Larger
1
Tank is 1.4 times
Larger
Reid Vapor Pressure (PSI)
2.3
8 to 16
6 to 12
Specific Gravity (@ 60/65 F)
0.794
.72-.78
0.78
Cold Weather Starting
Poor
Standard
As good as gasoline
5% Increase
Standard
3%-5% Increase
9
14.7
10
Relative tank size to yield
(Driving range equivalent to gasoline)
Vehicle Power
Air/Fuel Ratio (by weight)
Fuel Properties Ethanol vs.
Gasoline
Property
Analysis
Vapor Density
Ethanol vapor and gasoline vapor are denser than air and settles in
low areas; ethanol vapor disperses quicker
E85 will mix with water up to certain concentrations where it actually
separates
At equal volumes, E85 contains less energy than gasoline (approx .72)
Solubility in Water
Energy Constant
Flame Visibility
Specific Gravity
Ethanol Fuel flames are less bright than gasoline, but still very visible
in daylight.
Pure ethanol and blends are heavier than gasoline
Conductivity
Ethanol and Ethanol Blends are conductors; Gasoline is an insulator
Fuel-to-Air Ratio
E85 needs more fuel per pound of air relative to gasoline; E85 therefore
cannot be used in conventional vehicles
Ethanol has no carcinogenic compounds; E85 is a blend which
is potentially carcinogenic.
At low temps (32 F), E85 is more flammable than gasoline.
At normal temps, E85 is less flammaible (because of higher autoignition temp.)
Toxicity
Flammability
ASTM D5798-99 Standard Specification for Fuel Ethanol (Ed75Ed85)
For Automotive Spark-Ignition Engines
Electronic Fuel Injection System
The Fuel Delivery System
The Air Induction System
The Electronic Control System
Electronically Controlled Fuel Injection
The stoichiometric ratio for gasoline is around 14.7:1 (note: since
gasoline is a mixture of different hydrocarbon molecules, the
stoichiometric ratio is only approximate.
 The stoichiometric ratio for pure ethanol is approximately 9:1 and for E85, it
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is about 9.8:1. The reason for this difference in stoichiometric ratio is because
ethanol is an oxygenated fuel
An engine that is supplied with more fuel than is required by the
stoichiometric ratio is said to be running rich.
Conversely, an engine that is supplied with more air than is required by the
stoichiometric ratio is said to be running lean.
An overly rich mixture will not burn all of the fuel and will therefore be
inefficient. It will lose power and have poor fuel economy, as well as produce
an excess of the pollutants carbon monoxide (CO) and unburned
hydrocarbons (particulates).
A rich mixture will tend to make the engine run cool for two reasons:
(1) not all of the fuel is burned, and
(2) the excess liquid fuel will absorb heat from the cylinder in the process of
evaporation.
Leaning the mixture will generally cause the engine to heat up excessively near the
stoichiometric ratio and then the power will fall off, engine efficiency will drop, and the
engine will cool down as the mixture is leaned out further. Less mass in the fuel means
less mass in the exhaust gasses that create mechanical energy by expanding when
absorbing combustion heat.
 Automobile manufacturers try to achieve high fuel efficiency standards while
simultaneously keeping exhaust pollution low. Furthermore, the manufacturers are
required to warrant pollution control limits for the life of the vehicle.
 Today the life is 150,000 miles or more.
 In order to meet all of these requirements as the engine components wear with age and
use, the automobile manufacturers have decided that
 the engine cannot have fixed settings but must adjust to conditions and wear
dynamically. Therefore, since the 1980s, all new cars have been fitted with electronically
controlled fuel injection (EFI) systems.
 The engine control computer, ECU, provides the necessary signals at the correct times.
 The ECU receives signals about the ( i) operator’s intentions (throttle position), (ii) the
engine’s needs (manifold absolute pressure),
 (iii) engine speed and position,
 (iv) engine temperature,
 (v) air mass pulled into the engine (compensating for altitude and ambient air pressure)
through various sensors.
 The ECU uses these sensors to determine the precise timing of the pulsing of each fuel
injector. The ECU computes the desired air/fuel ratio at each moment in
 time from the sensors mentioned above, and then computes the precise time to open the
injectors to provide the necessary amount of fuel to the engine.
 In order to compensate for engine component wear, changes in fuel
composition, and other variable factors, modern EFI engines contain
one or more heated oxygen sensors (HO2 sensors) in the exhaust
system, just outside the engine. In spite of the common name, these
sensors don’t actually sense oxygen; they sense a factor called lambda
 which is the deviation (rich or lean) from stoichiometric ratio,
 as determined by the composition of the engine
exhaust gasses.
 The highlighted text is very important in this discussion. The HO2
sensor determines the actual fuel mixture that was just burned in the
engine in real-time, regardless of the type of fuel or the actual value of
its stoichiometric ratio! This operation is key to understanding how a
gasoline powered EFI engine responds to the presence of an alternative
fuel, such as ethanol, with a different stoichiometric ratio.
Ignition Timing.
 In order to achieve optimum engine performance, the pressure
wave from the exploding fuel’s exhaust gasses must hit top of the
piston at the time when the piston is just a little past the top dead
center of its travel. This causes the maximum pressure to build up
on the piston because the cylinder volume is at its smallest.
 If the spark ignites the fuel too late, the piston will have been
pulled down somewhat in the cylinder and the power stoke will
operate off of less compression, reducing the power delivered to
the engine from that power stoke.
 Conversely, if the spark ignites the fuel prior to the piston coming
past top dead center of its travel, the pressure wave may press
down on the piston while it is still being driven up in the
compression stroke, causing severe power loss, as the fuel ignition
now works against the engine for a short while in lieu of providing
power to it. This latter condition is known as pre-ignition or
“engine knock” and may damage the engine if it persists.
 All modern EFI engines have a sensor that informs the ECU of the position of
crankshaft or camshaft rotation dynamically, while the engine runs.
 The ECU’s software uses tables (sometimes referred to as engine control “maps”)
to determine the correct timing of firing the spark plug, as well as the desired
air/fuel ratio, given the instantaneous needs of the engine and its mode of
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operation
Note that it takes a short but finite time for the spark plug to ignite the air/fuel
mixture in the cylinder and for the resulting pressure wave to hit the top of the
piston. Thus, the spark must fire sometime before the piston is in the optimum
position.
Modern automobile engines differ somewhat in how the ignition timing is
controlled.
Some engines just use data computed by the ECU from the map and from the
engine position and speed sensors.
Other engines actually have “knock sensors” that detect engine knocking and
inform the ECU. These knock sensors, or similar sensors, allow the ECU
to determine the precise ignition firing time dynamically, achieving superior
performance when compared to a fixed setting in the map based only upon the
engine design.
Otherwise, ignition timing is programmed to be a little later (retarded) than
optimal to ensure that knocking does not take place due to varying fuel mixtures
(gasoline mixtures vary from tank to tank and with seasonal bends), engine wear,
carbon buildup in the cylinders, etc.
Modes of Operation of the EFI Automobile
Engine.
[ 1] Normal Operation Mode.
 The normal operation mode occurs when the engine is warmed up and the car
is driven normally. In actuality, the engine does not have to be fully warmed up;
it is only necessary that the heated oxygen sensor (HO2 sensor) is heated up to
around 600 degrees, which is necessary for its proper operation. Once the HO2
sensor is heated up, the ECU goes into what is called closed loop operation.
 In closed loop operation, the ECU continuously monitors the HO2 sensor
output and adjusts its pulsing of the fuel injectors in order to achieve the
correct air/fuel ratio; that is, the desired value of lambda from its engine
control map.
 As a general rule, the “correct” air/fuel ratio is a little on the rich side of the
stoichiometric ratio. This setting minimizes pollution and optimizes
performance, when used in conjunction with the catalytic converter and other
emission control equipment on the vehicle. The value that the ECU uses to
pulse the fuel injectors is known as the fuel trim.
 The whole idea is that the HO2 sensor feeds back data as to whether the engine
is running rich or lean (the lambda) and the ECU dynamically uses this data to
keep the engine running at an optimum level.
 This is the way that the manufacturer can guarantee to the EPA that the vehicle
is performing its emission control functions optimally, even as gasoline blends
change, ambient temperature and air pressure changes, and parts of the engine
wear and degrade over the life of the vehicle.
[2] Cold Cranking Mode of Operation.
 Cold cranking is that mode of operation when the engine is first started up
and the HO2 sensor is not yet warmed up to operating temperature.
 In this mode of operation, the engine operates off of a fixed set of
parameters in the engine control map of the ECU. When the engine is
cold, the fuel that is injected does not vaporize well and exists in the
cylinder as microscopic droplets of liquid fuel and not as a vapor. This
means that only the molecules of fuel that are on the surface of each
droplet can come in contact with oxygen from the air and burn. The fuel
that is inside of each droplet cannot burn until the surface molecules are
burned away.
 This condition requires a very rich air/fuel mixture to be introduced into
the cylinder in order to provide enough surface molecules of fuel to
provide sufficient power to crank the cold engine over.
 The cold cranking mode of operation lasts only a very short while on any
cold start, and represents a very small part of the overall engine operation.
It is therefore acceptable to the EPA for it to be inefficient, as long as the
HO2 sensor heats up rapidly and transitions the ECU into closed loop
operation in a short period of time.
3.] Wide Open Throttle Mode of Operation.
 Wide open throttle (WOT) is the mode of operation that occurs when
the driver presses down hard on the accelerator, e.g. for passing in a hill.
 In this condition, the driver wants the car to accelerate immediately;
wants a surge of power, as opposed to the engine gradually building up
power as it would in normal mode of operation. WOT requires an overly
rich fuel mixture to ensure maximum combustion and to prevent the
engine from getting too hot (rich cooling) and from fuel-starvation
misfiring under heavy load. In older, carbureted engine designs, rapid
depression of the accelerator would cause an accelerator pump to force a
highly enriched air/fuel mixture into the intake manifold.
 This would ensure that the maximum amount of fuel was available to
burn in the cylinder on the power stoke, even if a lot of the fuel was
wasted in the process.
 The rapid change in manifold pressure would additionally activate a
vacuum advance mechanism on the distributor to alter the normal
ignition timing to prevent the engine from knocking during WOT.

In modern EFI engines, the ECU senses the rapid depression of the accelerator
(or the rapid opening of the throttle) and uses pre-determined values in the
engine control map to immediately enrich the mixture and change the
ignition timing as well.
Consequently, the engine is operating open loop for the brief time that it is in
WOT (until the driver eases off the accelerator). Like the cold cranking open
loop mode, the WOT mode is inefficient from a fuel economy and pollution
perspective, but this is tolerable as the engine is expected to be in WOT mode
only for a very small part of its total operation.
Summary of Modes of Engine Operation.
So, a modern, EFI engine on an ordinary automobile that is designed to run on
gasoline operates mostly in a closed loop mode of operation. In this mode of
operation, the ECU is not dependent upon fixed air/fuel values in a map that has
been pre-engineered with the assumption of a certain type of fuel. Rather, the ECU
uses the HO2 sensor to dynamically keep the engine running at the optimal air/fuel
ratio as determined by actual measurement and not based upon any assumptions.
This factor is critically important in understanding what happens when ethanol is
blended into gasoline in various mixtures, and how a flex fuel automobile is able to
deal with high ethanol blends. It is also important that the open loop modes of
operation not be ignored. They are used only a very small percentage of the time,
but when they are used, the ECU is running off of pre-determined parameters and
is not able to adapt to differing fuel blends, unless special provisions are made to
do so (as in a flex fuel vehicle).
 increasing the ethanol blend beyond E15 in an EFI engine
that is not an FFV will, in all likelihood, cause no damage
to the engine and little or no degradation in performance
(the performance might increase, in fact; particularly if the
EFI can dynamically adjust the ignition timing to make
better use of ethanol’s very high octane rating).
 The fuel mileage will likely suffer because ethanol is an
oxygenated fuel and, particularly, if the ignition timing is
not dynamically alterable.
 The engine will run well in normal operation, but may have
some starting problems on cold mornings and may misfire
and overheat when accelerating very hard.
Fuel system corrosion
 We will read in many places that ethanol is more corrosive
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than gasoline. This is a somewhat misleading and
inflammatory statement.
Ethanol is an excellent solvent and will certainly attack
substances that are unaffected by gasoline.
Ethanol is also miscible in water and any water carried by
ethanol fuel may corrode parts of the fuel system.
However, ethanol designed to be blended with gasoline
must be dried (anhydrous), so water should not be a
problem, unless the fuel is sitting around exposed to the
atmosphere for long periods of time.
The bottom line here, though, is that the E10 standard has
been around since the 1990s, and automobile
manufacturers have had to address these issues even with a
low ethanol blend.
 Vapor lock:
you will find claims that ethanol will cause vapor lock in a non-FFV
owing to its Read Vapor Pressure rating. Any EFI fuel system is already
sealed for evaporative emission control (EVAP) and this prevents vapor
lock, whether for gasoline or ethanol or any other fuel for that matter.
 Phase separation:
 ethanol is miscible in water and gasoline is not.
 It has already been mentioned that ethanol must be dried in order to
mix with gasoline. If the mixture then comes in contact with water, the
ethanol will “bond” with the water (figuratively, not chemically) and, if
the water content gets above a few percent, the ethanol-water mix will
separate out from the gasoline (phase separation).
 The resulting ethanol-water mix will be high in ethanol content and the
gasoline part will be low in ethanol content. Some people claim that
this will have no effect on engine performance, based upon the
discussion of closed loop operation, above.
 However, problems with cold start and WOT, which are open loop
modes, could then be expected to occur if the fuel phase-separates.
Fuel Line Clogging
 Ethanol is an excellent solvent. Gasoline has lots of
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impurities in it.
An engine that has been running on gasoline for a
long time (say 40,000 miles or more) may have a
varnish of gasoline impurities coating the fuel system
components.
If ethanol is then placed in the gas tank, it may
dissolve off the varnish which will travel, in clumps of
gunk, into the fuel filter and clog up the fuel system.
Once again, automobiles built in 2001 or later will have
some protection against this varnishing action.
For older cars, it is recommended that ethanol be
blended into the gasoline in steps and that the fuel
filter be replaced after the highest operating blend is
reached.
Flexible Fuel Vehicle
 Flexible Fuel Vehicles, also known as FFVs, are designed to
run on gasoline, E85, or any combination of the two. The
“Flexible” nature of the vehicle gives the driver the
flexibility to switch back and forth between gasoline and
E85. How can this be?
 Ethanol contains more oxygen than gasoline. The vehicles
come equipped with an oxygen sensor which determines
the amount of ethanol in the fuel at any time. It provides
this information to the onboard computer, which then
adjusts the engine to maximize efficiency and
performance. The fuel may contain anywhere from zero to
85% ethanol. FFVs are widely available and include sedans,
minivans, SUVs, and pickup trucks.
Utilization of Alcohol Fuels in Compression
Ignition engines
 difficulties encountered:-
1.More alcohol fuel than diesel fuel is required by mass and
volume.
2.Large percentages of alcohol do not mix with diesel fuel, hence
use of diesel-alcohol blends is not feasible . Also, the blends were
not stable and separate in the presence of trace amounts of
water.
3.Alcohols have extremely low cetane numbers, whereas the diesel
engine is known to prefer
4.high cetane number fuels (45±55) which auto-ignite easily and
give small ignition delay.
5.Diesel fuels serve as lubricants for diesel engine. Alcohol fuels
do not have the same lubricating qualities.
6. The poor auto-ignition capability of alcohols is responsible for
severe knock due to rapid burning of vaporized alcohol [1,4] and
combustion quenching caused by high latent heat of
vaporization and subsequent charge cooling
Alcohol-Diesel dual fuel operation.
 The ignition of alcohol in dual fuel operation is ensured by the
high self-ignition diesel fuel. The most common methods for
achieving dual fuel operation are
1. Alcohol fumigation : the addition of alcohols to the intake air
charge, displacing up to50% of diesel fuel demand.
2. Dual injection : separate injection systems for each fuel,
displacing up to 90% of diesel fuel demand.
3. Alcohol±diesel fuel blend : mixture of the fuels just prior to
injection, displacing up to25% of diesel fuel demand.
4. Alcohol±diesel fuel emulsion : using an emulsifier to mix the
fuels to prevent separation, displacing up to 25% diesel fuel
demand.
Alcohol Fumigation
 Fumigation is a method by which alcohol is
introduced into the engine by carbureting,
 vaporizing or injecting the alcohol into the intake
air stream. This requires the addition of a
carburetor, vaporizer or injector, along with a
separate fuel tank, lines and controls.
 Fumigation has some following advantages:
 1. It requires a minimum of modification to the
engine, since alcohol injector is placed at the take
air manifold. Also, ¯ow control of the fuel can be
managed by a simplified device and fuel supply
system.
2. The alcohol fuel system is separate from the diesel system.
This flexibility enables diesel engines, equipped with the
fumigation system, to be operated with diesel fuel only. The
engine can switch from dual fuel to diesel fuel operation and
vice-versa by disconnection and connection of the alcohol
source to the injector.
3. If an engine is limited in power output due to smoke
emissions, fumigated ethanol could increase the power
output because alcohol tends to reduce smoke. This is
because of good mixing of the injected charge with alcohol.
4. Fumigation can substitute alcohol for diesel fuel. Up to 50%
of the fuel energy can be derived from alcohol by fumigation
The engine used for this study was a single
cylinder, four stroke, direct injection, variable
compression ratio, diesel engine with a swept
volume of 582 cm3. The engine is naturally
aspirated and water cooled. The engine was
coupled to an electrical generator through which
load was applied by increasing the field voltage.
A fixed 208 injection timing and 18
compression ratio were used throughout the
experiments. Indicators on the test bed show the
following quantities which are measured
electrically: engine speed, brake power and
various temperatures
Experimental apparatus and test
procedure
 Fig. 1 shows a schematic of the ethanol fumigation
system. Ethanol was fumigated into the intake air
charge and introduced in the engine as a vapor or mist,
dependent on the degree of vaporization which
occurred.
 A simple fumigation system was used, consisting of a
single hole, direct opening configuration spraying
nozzle. It was selected to achieve ethanol delivery at
relatively low pressure. The nozzle has a diameter of
about 0.25 mm. Since the obtained nozzle flow rate
was relatively high, the produced ethanol jet was
allowed to hit a partition in order to get ethanol
 mist which is directly mixed with air before entering the
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engine. An electrically driven air compressor was used to
supply ethanol to the nozzle.
The nozzle was positioned approximately 50 cm ahead of
the inlet manifold. This allowed the ethanol to be mixed
with the intake air for a sufficient period, providing
uniform mixing.
The intake manifold was provided with a transparent
window for optical inspection of the ethanol±air mixture.
Particulate exhaust emissions were drawn using a special
sampling probe. Particulates were collected on Tefloncoated glass fiber filters. The filters, manufactured by Pall
flex Products
Corporation (Type TX40 HI20-WW), measured 25 mm in
diameter and were held in a 25 mm Filter holder which is
connected to the diffuser end by a copper elbow fitting.
 An electrically driven air compressor was used to make
a vacuum such that exhaust
 particulates can be extracted continuously from the
main exhaust flow and collected on the filter. The flow
through the filter was maintained nearly constant by
using an orifice at the outlet of the sampler. This ¯ow
was measured by using an air ¯ow meter. The exhaust
gas was sampled and analyzed using a `Sun Gas
Analyzer' (SGA1000). The gaseous pollutants treated
in this study where CO, CO2, and HC. The
concentration of each
 gas is measured relative to the sample taken
continuously and digitally
Results and discussion
 The physical properties of diesel fuel are changed
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when ethanol is added in solution (blend).
The addition of ethanol causes the viscosity of diesel
fuel to decrease. Also, the addition of
ethanol in solutions with diesel fuel causes the cetane
rating to drop and the heating values
to be lower.
. Evaporation of ethanol in the intake air (fumigation
case) lowers the intake mixture
temperature and increases it's density. Thus, as more air is made available in the
cylinder, greater amounts of power can be generated if the right proportion of
fuel is added. Figs. 3 and 4 show the e€ect of ethanol substitution on CO and
HC production, respectively.
The maximum increase in CO and HC emissions was at 20% ethanol for both the
fumigation and blends methods. Also, the CO and HC emissions were always
higher when using the blended fuels than when the engine operated with
fumigation.
For 20% ethanol fumigation, the increase in CO emissions was in the range of
21±55% at the speed range used, and for 20% ethanol as a blend with diesel
fuel, the increase in CO emissions was in the range of 28±71.5% at the same
speed range used.
The increase in the CO levels with increasing ethanol substitution is a result of
incomplete combustion of the ethanol±air mixture. Factors causing
combustion deterioration (such as high
latent heats of vaporization) could be responsible for the increased CO
production.
Combustion temperatures may have had a signi®cant e€ect. A thickened quench
layer created
by the cooling e€ect of vaporizing alcohol could have played a major role in the
increased CO production.
Conclusions
 The optimum percentage of ethanol appears to be 20 and
15% for ethanol fumigation and ethanol-diesel fuel blends
operations, respectively. The use of 20% ethanol as a
fumigant can produce an increase of 7.5% in the brake
thermal efficiency, 55% in CO emissions levels and 36% in
HC emissions levels. Also, this fumigation percentage
produces a decrease of 48% in engine smoke and 51% in
soot mass
 The use of 15% ethanol as a blend with diesel fuel can
produce an increase of 3.6% in
 brake thermal efficiency, 43.4% in CO emissions and 34.2%
in HC emissions. It can also produce a reduction of 33.3%
in engine smoke and 32.5% in the soot mass concentration.
 The maximum increases and decreases mentioned in the
above results are over the entire speed range chosen.