Millions of cars powered by ethanol-blended fuels are on America's roads, and
the number continues to grow. American motorists have driven more than three
trillion trouble-free miles on ethanol blended fuels. Ethanol's original use was as
a gas extender when foreign oil prices skyrocketed. As a result of the phasing
out of leaded fuel, ethanol became popular as a high quality octane booster.
Because of environmental concerns, ethanol was used as an emission reducing
oxygenate. As an oxygenate, ethanol has a high oxygen content and burns more
completely and pollutes less.
Ethanol-blended fuel sales represents over 11% of all automotive fuels sold in the
United States. The U.S. produces approximately 1.6 billion gallons of ethanol each
year from more than 50 ethanol producing facilities operating in 20 different
states. Iowa is a leader in the use of ethanol-blended gasoline. More than 40%
of the gasoline sold in Iowa contains 10% ethanol (E-10).
The Clean Air Act of 1990 and the National Energy Policy Act of 1992 created new
market opportunities for alternative fuels by phasing in requirements for fleet
vehicles to operate on cleaner fuels. State governments are recognizing the
economic, energy, and environmental benefits of ethanol. Many Midwestern
states and the federal government operate many E-85 variable fuel vehicles in
their fleets. Iowa is a leader in the introduction and operation of one of the
nation's largest variable fuel fleets. These vehicles are capable of operating
on E-85, a blend of 85% ethanol and 15% unleaded gasoline. The 200-proof
ethanol is made from Iowa corn. The small percentage of gasoline enhances
starting in extremely cold weather.
Brazil has used ethanol blends since 1939. The oil prices in the 1970's prompted
a government mandate to produce neat-ethanol fueled vehicles in order to reduce
dependence on foreign oil while providing value added markets for its sugar cane
producers. Today, there are more than 4.2 million ethanol-powered vehicles
(about 40% are passenger vehicles), which consume nearly 4 billion gallons of
ethanol annually in Brazil. It is the largest transportation fuels market in the
world.
Clean Air Act requirements to make cleaner burning, reformulated gasoline (RFG) with
lower volatility, and fewer toxins have created an increased interest in ethanol-
based ethers such as ethyl tertiary butyl ether (ETBE). ETBE is a chemical compound
produced by reacting ethanol and isobutylene (a petroleum-derived by-product
of the refining process).
ETBE has characteristics superior to other ethers including: low volatility, high
octane value, reductions in carbon monoxide and hydrocarbon emissions, and
superior driveability. RFG is required in certain carbon monoxide non-attainment
areas in the U.S.
WHAT IS FUEL ETHANOL?
Ethanol is a high octane, water free alcohol produced from the fermentation of
sugar or converter starch. It is used as a blending ingredient in gasoline or as a
raw material to produce high octane fuel ether additives. Ethanol is made from
grains, mainly corn, or other renewable agricultural or forestry products such
as wood, brewery waste, potatoes, cheese whey, paper waste, beets, or vegetable
wastes.
THE CAR OWNER
Iowa auto dealers are recommending ethanol-blended fuels more and consumers
are blaming ethanol less for engine performance problems. A 1996 survey by
the Iowa Corn Promotion Board (ICPB) revealed that nine out of ten dealers used
ethanol in their personal vehicles. Thirty percent of the dealers surveyed
recommend ethanol use. This is an increase from seventeen percent ten years ago.
Over half of the dealerships surveyed indicated their customers had no concerns
about using ethanol blends and reported benefits including: reduced knocking
and pinging, improved mileage, better acceleration, and improved starting
qualities.
Iowa independent automotive technicians trust their family cars to ethanol blends.
A 1997 survey by the ICPB indicates that nine out of ten technicians used ethanol
in their personal vehicles and reported the same benefits as Iowa auto dealers.
Over half of the technicians responding indicated their customers were comfortable
about using ethanol blends.
Ethanol blends are approved under the warranties of all domestic and foreign
automobile manufacturers marketing vehicles in the United States. In fact, the
nation's top three automakers, Chrysler, Ford and General Motors, recommend
the use of oxygenated fuels, such as ethanol, because of their clean air benefits.
Ethanol is a good cleaning agent. It can loosen contaminants and residues that
have been deposited in a vehicle's fuel delivery system and collect in the fuel
filter. This problem has happened occasionally in older cars, and can be easily
corrected by changing fuel filters. The problem seldom occurs on today's
modern vehicles.
All alcohols have the ability to absorb water. Condensation of water in the fuel
system is absorbed and does not have the opportunity to collect and freeze. Since
ethanol blends contain at least 10% ethanol, it is able to absorb water and
eliminates the need for adding a gas line antifreeze.
Ethanol is a fuel for old and new engine technology. Automotive engines older
than 1969 with non-hardened valve seats may need a lead substitute added to
gasoline or ethanol blends to prevent premature valve seat wear. Valve burning
is decreased when ethanol is used because ethanol burns cooler than gasoline.
Many high-performance racing engines use pure alcohol for that reason. Modern
computerized vehicles of today, when operating correctly, will perform better than
non-computer equipped vehicles. Improved performance is due to the vehicle's
computerized fuel system being able to make adjustments with changes in operating
conditions or fuel type. Some of the chemicals used to manufacture gasoline, such
as olefins, have been identified as a cause of deposits on port fuel injectors.
Today's gasoline, blended and unblended, contains detergent additives that are
designed to prevent fuel injector and valve deposits.
A car owner should spend time with the vehicle's owner's manual. This will help
to answer many questions. The owner/driver should note the octane requirement
or AKI index number of gasoline required for proper engine performance for the
vehicle. Then note the octane number on the sticker on the gas pump making
sure it is not less than the required number. Using a higher octane number will
not realize better economy unless engine knock or ping already exists.
To help insure proper engine operation and keep fuel costs to a minimum, follow
these guidelines:
· Purchase fuel from a busy station to be sure fuel is fresh and less likely to be
contaminated with moisture.
· Keep the fuel tank above one-quarter full, especially during cold weather, to
help reduce condensed moisture and gas line freeze-up.
· Do not purchase a fuel with a higher octane rating than is necessary.
· Do not purchase fuel from a retail outlet when a tanker truck is filling the
storage tanks. Dirt, rust, and water may be stirred up.
· Do not overfill the gas tank. After the nozzle clicks off, add just enough fuel
to round up to the next dime. This will prevent damage to the vehicle's fuel
evaporative system.
Ethanol's performance has been proven by years of use. The Nebraska State
Highway Patrol has been successfully using ethanol-blended fuel for the past
fourteen years. By executive order of Iowa's Governor, all state vehicles must
use a 10% ethanol-blended fuel. These state vehicles have been successfully
using ethanol blends for several years. Three-time IHRA world champion funny
car driver, Mark Thomas, used ethanol to fuel his winning Dodge Avenger.
THE AUTOMOTIVE TECHNICIAN
The quality of fuel used in any motor vehicle engine is very important to its long
life and proper operation. If the fuel is not right for the air temperature or if
fuel changes to a vapor incorrectly, driveability will suffer.
Gasoline is a complex mixture of approximately 300 various ingredients, mainly
hydrocarbons, refined from crude petroleum oil for use as fuel in engines. Refiners
must meet gasoline standards set by the American Society for Testing and Materials
(ASTM), the Environmental Protection Agency (EPA), some state requirements,
and their own company standards.
Gasolines are most commonly rated based on their Antiknock Index (AKI), a
measure of octane quality. The AKI is a measure of a fuel's ability to resist
engine knock (ping). The AKI of a motor fuel is the average of the research
octane number and the motor octane number (R + M)/2. This is also the
number displayed on the octane decal posted on a gasoline pump. In general,
a low research octane could cause a low to medium speed knock and run-on
or dieseling after the engine is shut off. A low motor octane could cause
engine knock when power is needed during acceleration such as passing or
climbing hills. A typical average octane number of 87 would contain a research
octane of 92 and a motor octane of 82. However, it could also be the average
of 94 and 80 depending on the availability of blending products on hand at the
refinery. These different blends can affect engines differently, depending on
the octane requirement of that particular engine, and explains why engines
can perform differently with a change of fuel.
Factors affecting the octane number requirement include:
-- compression ratio
-- barometric pressure/altitude
-- ignition timing
-- temperature
-- air fuel ratio
-- humidity
-- combustion temperature
(intake manifold heat, inlet air temperature, coolant temperature)
-- exhaust gas re-circulation rate
-- combustion chamber deposits
-- combustion chamber design
Using a higher octane or AKI fuel will not increase gas mileage unless the engine
is knocking or pinging with the lower octane fuel.
Gasoline is metered in liquid form through the fuel injectors or carburetor and is
atomized, mixed with air, and vaporized before entering the cylinders. It is very
important that a fuel's tendency to evaporate is controlled. A fuel's ability to
vaporize or change from a liquid to a vapor is referred to as its volatility. If
volatility is too low (not volatile enough), symptoms could include: poor cold
start, poor warm up performance, poor cool weather driveability, increased
deposits in the crankcase, combustion chamber, and spark plug, or unequal
fuel distribution. If volatility is too high and too much vapor is formed, it
could cause a decrease of fuel flow resulting in vapor lock, loss of power,
rough running or stalling, decreased fuel mileage, or increased evaporative
emissions leading to overloading of the fuel evaporative canister. Refiners
are required to deliver the correct volatility of fuel for winter, summer, and
fall/spring. A vapor pressure test to determine volatility of a fuel sample
can be performed by a technician using special test equipment and following
a specific procedure. It is referred to as a Reid Vapor Pressure (RVP) test.
In Iowa, we would like to see an RVP of 9 psi for summer and 15 psi for winter.
Ethanol blends (E-10) are allowed an increase in the RVP of 1.0 psi. During
the mid 1980's, the RVP of summer fuels was found to be as high as 10.5 psi.
due to additives used to increase octane ratings. This caused drastic
increases of driveability problems, many of which were blamed on ethanol,
when the problem was with the base gasoline used for blends.
In addition to AKI and volatility, other fuel standards exist for copper
corrosivity, stability in storage, sulfur content, metallic additives, and
temperature for phase separation. It is important to note that gasoline retains
its original "fresh" state for 90 days. It is usually 30 days old when it
becomes available for consumer use. If gasoline is to be stored for longer
than 60 days, a good gas stabilizer additive should be used by following
the product directions. Other additives found in gasoline are detergents
and deposit control additives, anti-icers, fluidizer oils, corrosion inhibitors,
anti-oxidants, metal deactivators, and lead substitute additives.
Gasoline Additives
Additive Purpose
Detergents/deposit control additives* Eliminate or remove fuel system deposits
Anti-icers Prevent fuel-line freeze up
Fluidizer oils Used with deposit control additives to
control intake valve deposits
Corrosion inhibitors To minimize fuel system corrosion
Anti-oxidants To minimize gum formation of stored
gasoline
Metal deactivators To minimize the effect of metal-based
components that may occur in
gasoline.
Lead replacement additives To minimize exhaust valve seat recession
*Deposit control additives can also control/reduce intake valve deposits
Detergents play an important role in preventing deposit buildup of port fuel
injectors, intake valves, and combustion chamber deposits. Deposits on
injectors and intake valves have been corrected by changes in detergents;
however, some engines are currently experiencing a buildup of deposits in the
combustion chamber. Gas tank additives for injectors are designed to keep
deposits from collecting. Special equipment and cleaning agents must be used
to remove deposits. These special cleaning chemicals must not be used in the
gas tank.
Compatibility of materials is an issue, especially with certain brands of port
fuel injectors. Causes of failure have not been verified, but a newly designed
replacement injector prevents the problem from reoccurring.
A simple test a technician might use is to determine the amount of alcohol
present in gasoline. This can be done using a "water extraction method". A
graduated glass cylinder, usually 100 milliliters (ml), is used for the test. Place
100 ml of the gasoline sample in the graduated cylinder. Add 10 ml of water
into the cylinder, stopper the top, and shake thoroughly for one minute. Set
aside for two minutes. If no alcohol is present, the 10 ml of water will settle to
the bottom of the cylinder. If alcohol is present the alcohol will drop to the
bottom, along with the water, increasing the bottom layer to greater than 10ml.
Subtract 10 from total bottom layer and remainder will be the percentage of
alcohol in the gasoline. Over-blends of ethanol were found during the early
(1970's) use of gasohol due to the methods used to obtain the products and
deliver them. Today both gasoline and ethanol are located at a pipeline
terminal and are monitored closely for proper blending.
While ethanol is the alternative fuel of choice, methanol has been considered.
Methanol is made from natural gas or coal, and is also known as "wood alcohol".
It is highly corrosive, more volatile than ethanol, and more damaging to plastic
and rubber fuel system components known as elastomers.
Ethyl Tertiary Butyl Ether (ETBE) and Methyl Tertiary Butyl Ether (MTBE)
are both high octane, low volatile, oxygenated fuel components made by
combining alcohol with isobutlylene. MTBE is permitted in unleaded gasoline
up to a level of 15%. ETBE can be added to gasoline up to a level of approximately
17%. ETBE is made by using ethanol while MTBE is made using methanol.
Many car company warranties do not cover the use of methanol-based fuels,
while all automakers approve of the use of ethanol.
NON-AUTOMOTIVE USE
Over the past years, there has been a great deal of confusion about the use
of oxygenated fuels in non-automotive applications. Initially, this confusion
centered primarily around ethanol-blended fuel. The expanded use of
oxygenated fuels in recent years has prompted concerns about gasoline
containing MTBE.
Past concerns identified by equipment manufacturers fall into five categories.
These include: materials compatibility (metals, plastics, elastomers), lubricity,
enleanment, storage considerations, and overblends. Some manufacturers
found it necessary to upgrade materials used in fuel systems. As was
mentioned in the previous section, base gasoline composition changes also
took place and caused some of the compatibility problems. Remember also
that gasoline standards are set for automotive use. Gasoline must operate
properly in a Dodge Viper as well as a string trimmer. The limited data
available indicates that ethanol blends may improve lubricity slightly. It
may be necessary to reset or "rejet" carbureted engines to allow increased
fuel mixtures because of the increased oxygen content in ethanol. Computerized
systems will automatically compensate for the extra oxygen. Since many of
these applications are for seasonal use, the "life" of gasoline in storage being
limited to 90 days requires special attention. Draining fuel systems and
refilling them with fresh fuel or using a gas stabilizer will be necessary.
Consumers and technicians should focus on the recommendations by the
equipment manufacturers when it comes to fuel usage. They are the most
familiar with the quality of their products and whether or not they will operate
satisfactorily on specific fuels. In 1994, Downstream Alternatives Inc.
reviewed each company's owner's manuals and found that all manufacturers
of non-automotive equipment/engines either approve or make no mention
of using 10% ethanol blends (E-10).
E-85 ETHANOL FUEL
It has already been mentioned that Iowa is a leader in the introduction and
operation of one of the nation's largest fleets of flexible fuel vehicles. The
driving forces for this type of automotive fuel technology are: society's
multiple concerns of increasing air pollution from fossil fuels like gasoline,
our dependence on foreign suppliers for half our fuel needs, and the dim
prospects for gasoline in the future as the world's oil supply dwindles.
The Iowa Corn Promotion Board helped introduce E-85 vehicle technology by
purchasing the first flexible fuel car in Iowa. In 1994, ten percent of Iowa's
state fleet vehicles operated on alternative fuels like ethanol. By 2000, seventy
percent of the state fleet is able to operate on alternative fuels. These cars are
virtually identical to regular gasoline vehicles except for some variable fuel features.
Flexible fuel E-85 vehicles have been designed for versatility. They will operate
with unleaded gasoline or any mixture of gasoline and ethanol up to an 85 percent
concentration. A key component is a sensor, which determines the percentage
of ethanol in the fuel. A computer system then optimizes performance and
adjusts emission control devices.
Formal testing helped Iowa evalute ethanol's role as an alternative fuel. E-85
state vehicles were put through their paces in various settings including urban,
rural, and highway driving. Performance in hot and cold weather conditions and
ethanol's ability to reduce emissions were evaluated. Performance, realiability,
cost of operations, and emissions were monitored and each driver was surveyed
about the driveability and operation of the cars. The cars received high marks in
each category. Emissions tests on the E-85 vehicles and on a control vehicle
operating on gasoline were conducted at various mileage levels up to 100,000 miles.
Tests showed the flexible fuel E-85 cars performed well with significant reductions
in emissions when compared to vehicles using unleaded gasoline. Reductions in
carbon monoxide and hydrocarbons, two particularly troublesome pollutants, are
reduced significantly. Ethanol is one of only two liquid fuels available that
combats global warming because of its raw material. As corn grows, it
converts carbon dioxide into oxygen.
As was mentioned in the Introduction to Ethanol module, automakers
are offering more flexible fuel vehicles. Purchase price of these vehicles
has been comparable to the base price of a gasoline model. It is expected, since
E-85 is a cleaner burning fuel, that the life of a flexible fuel vehicle will be
somewhat longer than a comparable gasoline vehicle. A gallon of E-85 ethanol
fuel contains about 2/3 the energy of a gallon of gasoline. Based on ethanol's
energy content (BTU), you might assume the mileage would be 2/3 less; but,
fleet experience to date has found miles per gallon on ethanol have been around
10 percent higher than a direct BTU comparison. The E-85 Ford Taurus has been
averaging around 20 miles per gallon and has experienced a 5 percent gain in
horsepower. The price of E-85 ethanol fuel is about the same as the price of
premium gasoline.
STUDY QUESTIONS
True / False: Place a T in the blank provided for each True statement. If the
statement is False, write the correct word that replaces the underlined word(s)
to make the statement True in the blank provided.
____________________ 1. Ethanol's original automotive use was as a/an
octane booster.
____________________ 2. When lead was removed from gasoline, ethanol
was used as a/an product extender.
____________________ 3. Concerns about air quality have caused ethanol
to be used as an oxygenate.
____________________ 4. Over 60% of gasoline sold in Iowa is E-10.
____________________ 5. Clean air laws passed in the early 90's
require fleet vehicles to operate on cleaner
fuels.
____________________ 6. Vehicle fleets in Iowa and other Midwestern
states are using vehicles operating on 100%
ethanol.
____________________ 7. The United States is the largest user of
ethanol in the world.
____________________ 8. Reformulated gasoline has lower volatility and
fewer toxic byproducts, which meets the Clean
Air Act requirements.
____________________ 9. Reformulated gasoline is a high octane, water-
free alcohol made by fermenting sugar.
____________________ 10. Ethanol is used as a blend with gasoline or as
a raw material to make high octane additives.
Multiple Choice: Place the answer that best answers the question in the blank
provided at the left of each question.
______ 1. Which of the following statements is/are true?
I. The majority of Iowa auto dealers have used ethanol blended
fuels.
II. The majority of Iowa independent automotive technicians have
used ethanol blended fuels.
A. Only statement I is true.
B. Only statement II is true.
C. Both statements are true.
D. Neither statement is true.
______ 2. Ethanol-blended fuels are approved under the warranties of:
A. Chrysler
B. Ford
C. General Motors
D. Toyota
E. All domestic & foreign car manufacturers
______ 3. Ethanol has the ability to absorb water which eliminates:
A. Carburetor icing
B. The need to use a gas line antifreeze
C. Engine ping
D. Changing fuel filters
______ 4. Which of the following statements is/are true?
I. Ethanol burns hotter than gasoline.
II. Computer equipped vehicles will recognize the use of ethanol
and make necessary adjustments.
A. Only statement I is true.
B. Only statement II is true.
C. Both statements are true.
D. Neither statement is true.
______ 5. The use of a higher octane gasoline:
A. Will result in increased fuel economy and performance, only if
engine knock or ping was previously present.
B. Will decrease fuel economy and performance.
C. Decreases deposits on intake valves and fuel injectors.
D. Will decrease vapor lock.
Fill in the Blank: Write the word or words which best completes each statement.
1. ____________ is a mixture of 300 chemicals, most of which are refined from
crude oil.
2. The ____________________ is the measure of a fuel's ability to resist engine
ping or knock.
3. If an engine's octane requirement is higher than the fuel octane number,
____________________ results.
4. A fuel's ability to change to a vapor is called ____________________.
5. Reid Vapor Pressure requirements for summer use of unblended fuel in Iowa
is ____________ psi.
6. Gasoline is "fresh" for _________ days after it is manufactured.
7. "Wood alcohol" or ___________________ is very corrosive and volatile
and will damage certain fuel system components.
8. ETBE can be blended with gasoline up to ___________%.
9. _________% of small or non-automotive engine manufacturers either
approve of or make no mention of the use of E-10 blends in their respective
owners' manuals.
10. Vehicles which will operate on unblended, or any blend of ethanol up to
85%, are called ___________________ fueled vehicles.
Essay: Completely answer each of the following questions.
1. Engine design and compression ratio determine the fuel octane requirement of
an engine. List six other causes of increased octane requirement of an engine.
2. State how the improper volatility of fuel can affect engine operation.
3. What effects do E-85 vehicles have on the atmosphere?
PROJECTS
1. Prepare a report about your family car. What kind of gasoline does your
family put in your car? Does it contain additives? Do the additives make
a difference in how the car runs? Do they make a difference in the amount
of pollution cars produce?
2. Collect new car brochures. Compare the EPA mileage figures and prices
for each. Use the price of gasoline to figure out which car will cost more
over a five year period, based only on the purchase price of the car and cost
of gasoline to drive it 12,000 miles per year. Make it more interesting by
using one flexible fuel vehicle in your example.
3. Test your math. Assume that a 1996 Ford Taurus gets 30.9 miles per gallon
on a mixture of 10 percent ethanol and 90 percent gasoline, and only 23.1
miles per gallon with a mix of 85 percent ethanol and 15 percent gasoline.
If pure gasoline costs $1.25 per gallon, how cheap must ethanol be to make
the cost per mile the same for both mixtures?
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