ETHANOL - AN ALTERNATIVE FUEL

NOTE: The Activity Guide titled "ALTERNATIVE FUELS - WHAT ARE THEY?" must be completed before using this guide.

GOAL:: To assist students in understanding ethanol as an optional fuel and the technological effects of ethanol as an alternative fuel.

OBJECTIVES:: The students will learn ethanol's effects as an alternative fuel with respect to vehicle fuel economy, the environment, and technical changes in the vehicle.

LESSON/INFORMATION:: Several factors affect the use and selection of any fuel. Among the important ones are engine design, net energy per pound, net energy per gallon and the sulphur content of alternative fuel properties. Refer to chart below.

SELECTED PROPERTIES OF PRESENTLY AVAILABLE FUELS.


Physical State	Gasoline Liquid	Liquified Petroleum Gas	Compressed Natural Gas	Methanol Liquid	Ethanol Liquid
Net Energy Content BTU/lb	18,700 19,100	19,800	21,300^a	8,600	11,500
Octane Number Range (R + M) ÷ 2	87 - 93	104^b	120^b	99	100
Sulfur Content (W + %)	0.02 - 0.045	Neg^c	Neg^c	None	None

a - Pure Methane

b - Octane ratings above 100 are correlated with given concentration of tetraethyl lead in 150-octane

c - Natural sulfur content very low but measurable.
Source: Steering A New Course: Transportation, Energy, and the Environment, pages 75, 76.

Measuring a fuel's relative potential energy can easily be done by defining that fuel's Btu content. A Btu is defined as the amount of heat necessary to raise one (1) pound of water, one (1) degree fahrenheit.

Present design internal combustion (IC) engines run on liquid fuels. Ethanol requires few if any engine modifications to extract the maximum power from this fuel. Ethanol is reported to lower tailpipe emissions. Ethanol is more difficult to ignite than gasoline, especially in cold temperatures. Thus, for an engine to operate on 100 percent ethanol, the ignition and fuel systems may need modifications. Ethanol is energy-intensive to produce and therefore could affect the total energy-cost cycle. Ethanol may be produced from agriculture crops and is considered a renewable energy resource. However, environmental considerations such as increased use of fertilizers and the associated problems with ground water runoff and limited supplies of ethanol when made from corn or other grain crops, hinders its widespread usage. When ethanol is used as a gasoline additive, antiknock compound and fuel extender, it becomes more economical with very positive results, especially from the emissions standpoint. It contains zero sulfur, thereby reducing tailpipe acids significantly. Of the alternative fuels presently available, ethanol has the lowest Btu/lb. net energy yield.

Several manufacturers have begun developing "multi-fuel" engines, that is, engines that operate on many different fuels and in varying ratios. A key component in these multi- fueled vehicles is the computer. Special sensors detect the type of fuel(s) present. The fuel injection, ignition and emissions control systems are recalibrated to accommodate the present fuel(s). Limited production of 100 percent ethanol vehicles is being offered in some Canadian and South American markets. For several years Illinois, Iowa, Nebraska, and Michigan have mandated a 10 percent ethanol to 90 percent gasoline mix for fuels used in state-owned vehicles. These blends extend gasoline fuel stocks, reduce air pollution, and support the agricultural community. Federal subsidies have brought production costs of this antiknock additive into close competition to the cost of producing other antiknock additives.

Initial changeover from gasoline to ethanol could present some problems in the distribution system. Ethanol is a detergent and has the ability to absorb water. Accumulated sediment and water sludge in storage tanks, pipelines, and in the vehicle fuel tanks could clog filters and create other operational problems. These systems must be scrubbed clean and prepared prior to the introduction of ethanol fuels. Ethanol, in a highly concentrated state, can be corrosive to some automotive metals, rubber, and plastic components. Since the mid 1980's, most manufacturers have redesigned their fuel systems to accommodate ethanol in a dilute mixture. Owner's manuals describe acceptable ethanol concentration levels.

ACTIVITY 1:

List Advantages of Ethanol:		List Disadvantages of Ethanol:

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ACTIVITY 2:

Use the following chart for this activity.

1. Determine what type of vehicles are available in your area which use gasoline or ethanol or ethanol blends. What are the recommended fuel percentage concentrations for each vehicle?

2. Determine if conversion systems are available in your area to run 100% ethanol.

3. For each vehicle or conversion system, determine each of the following:

a. Extra cost for a new vehicle; cost (materials and labor) to install the system;

b. maintenance requirements, changes if any;

c. changed operational characteristics;

d. available (number) fueling stations in immediate area;

e. cost for fuel compared to pure, standard gasoline.


CNG FUELED VEHICLES
Type of Vehicle		Type of System		Fuel System
Make, Model, etc.	Type of Fuel(s) can be used	Factory Installed	Locally Installed	Cost (Materials and Labor)	Maintenance Changes	Operational Characteristics Changes	Available Fuel Station (Number Locally)	Cost of Fuel
				$
				$
				$
				$
				$
				$

COST PER GALLON (OR EQUIVALENT): PURE ETHANOL: $ _______________________________; ETHANOL BLEND: $_______________________; STANDARD GASOLINE:$_________________________

INFORMATION CHECK: Directions: Indicate whether the following statements are true or false. If the statement is false, explain why it is false.; 1. Ethanol may be used as a gasoline antiknock additive.; 2. Ethanol contains moderate concentrations of sulphur, thus it negatively impacts the environment.; 3. Of the currently available alternative fuels, ethanol yields the most Btu/lb. net energy.; 4. A fuel distribution system that is changed over from gasoline to ethanol may experience some contamination problems.; 5. Ethanol, in its concentrated state, may be corrosive to some metals, rubber, and plastic.

TEACHER'S NOTES: Students MUST complete the guide, "Alternative Fuels - What are They?" before they attempt this activity. A comparative understanding of alternative fuels is necessary before they can successfully proceed with this guide.; Ethanol is a very misunderstood alternative fuel. Many technicians and pseudo automotive buffs equate ethanol with methanol. They also relate "horror stories" of how alcohol based fuels have ruined automotive fuel systems. In truth, ethanol, in low concentrations, will not harm late model vehicles. The only possible harm could come if a highly concentrated mixture was induced into the system. Methanol, however, is highly corrosive even in moderate concentrations. Another possible side effect of changing over to ethanol blended fuels is the possible detergent action on an older vehicle's fuel tank and lines. A system contaminated with fuel sludge and/or water will be cleaned by the ethanol. In an extreme case, fuel filters could repeatedly clog until the system would be entirely cleansed of these contaminants.

ANSWERS TO INFORMATION CHECK:: 1. True. At present, this is the primary use for ethanol as an automotive fuel.; 2. False. Ethanol contains NO sulphur. Ecologically, this is one of ethanol's greater attributes.; 3. False. Ethanol has a low Btu/lb. yield. Decreased fuel economy is one of the greatest impediments to pure ethanol use. When used as an antiknock compound, in 10% or less concentration, the decreased mpg is almost immeasurable.; 4. True. Based on the experience of the 1980's, to prevent fuel contamination, distributors must clean their system fuel supply before introducing ethanol blended fuels.; 5. True. In low concentrations, 10% or less, ethanol is not harmful to vehicle components.

REFERENCES:: New Transportation Fuels, American Petroleum Institute, Washington, D.C.-1991. Special Issue Department, Public Affairs Group, _______.; The Automobile. Earth Day, 1990, Fact Sheet, Stanford, CA. 1990.; Gordon, Deborah, Steering A New Course: Transportation, Energy, and the Environment. A Report by the Union of Concerned Scientists, Cambridge, MA 1991.; Motor - Vehicle Fuel Efficiency and Global Warming. Union of Concerned Scientists Briefing Paper: Cambridge, MA. 1991

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