ethanol as fuel for recreational boats - dartmouth college

The Thayer School of Engineering at Dartmouth College

ENGS 190/ENGG 290 Final Report

Ethanol as Fuel for Recreational Boats

9 March 2004

Sponsor/Advisor: Professor Charles Wyman

Group Members:

Erik Dambach, Adam Han, Brian Henthorn

www.dartmouth.edu/~ethanolboat

Ethanol as Fuel for Recreational Boats Final Report

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Table of Contents I. INTRODUCTION............................................................................................................................... 1

NEED STATEMENT ................................................................................................................................ 1 OBJECTIVES.......................................................................................................................................... 1

II. PROBLEM BACKGROUND............................................................................................................ 2 CASE AGAINST GASOLINE..................................................................................................................... 3

III. CASE FOR ETHANOL ................................................................................................................... 9 AQUATIC TOXICITY ANALYSIS ............................................................................................................ 13

IV. SPECIFIC FOCUS: CALIFORNIA .............................................................................................. 14 CASE FOR CALIFORNIA ....................................................................................................................... 14 ENVIRONMENTAL REGULATIONS......................................................................................................... 15 INFRASTRUCTURE FOR INTRODUCING ETHANOL AS A FUEL IN CALIFORNIA............................................ 18

V. HISTORY OF ETHANOL USE IN ENGINES............................................................................... 26 VI. ENGINE CHOICE JUSTIFICATION .......................................................................................... 29

THE FOUR-STROKE ENGINE ................................................................................................................ 31 VII. ENGINE MODIFICATIONS NECESSARY FOR ETHANOL OPERATION........................... 32 IX. MODIFICATIONS TO THE OUTBOARD ENGINE .................................................................. 35

JET DESIGN ........................................................................................................................................ 35 MATERIALS ETHANOL COMPATIBILITY................................................................................................ 36 COLD START SOLUTIONS .................................................................................................................... 40

X. GOAL ENGINE SPECIFICATIONS.............................................................................................. 44 XI. ENGINE TESTING........................................................................................................................ 44

EMISSIONS ......................................................................................................................................... 45 POWER ............................................................................................................................................... 49 EFFICIENCY WITH POWER ................................................................................................................... 52 COLD-START ...................................................................................................................................... 53 WEIGHT ............................................................................................................................................. 56 JET SIZE DETERMINATION................................................................................................................... 57

XII. ECONOMIC ANALYSIS OF ENGINE....................................................................................... 58 XIII. DISCUSSION OF SPECIFICATION RESULTS....................................................................... 60 XIV. MARKETABILITY..................................................................................................................... 61 XV. CONCLUSIONS AND RECOMMENDATIONS FOR FUTURE STUDIES.............................. 62 XVI. ACKNOWLEDGEMENTS......................................................................................................... 64 XVII. LIST OF WORKS CITED......................................................................................................... 65


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Figures Figure 1. USA Ethanol Production Capacity..................................................................20 Figure 2. Original Main Jet............................................................................................36 Figure 3. Tubing in Fuel System....................................................................................38 Figure 4. Engine test set-up ...........................................................................................45 Figure 5. Hydrocarbon and NOx Emissions...................................................................48 Figure 6. CO and CO2 Emissions ...................................................................................49 Figure 7. Maximum Power ............................................................................................51 Figure 8. Full-Throttle Efficiency with Power ...............................................................53 Figure 9. EPA 2006 Emissions Limits .......................................................................... E1 Figure 10. CARB 2008 Emissions Limits for Marine Outboards and Personal.............. E1 Figure 11. Schematic for Ethanol Production.................................................................F3 Figure 12. US Average Ethanol and Corn Prices........................................................... G1 Figure 13. Fuel Ethanol Terminal Market Price (18 Month History) ............................. G2 Figure 14. Fuel Ethanol Terminal Market Price (10 Year History) ................................ G3 Figure 15. Fuel System Schematic................................................................................ L2 Figure 16. Carburetor Schematic .................................................................................. L3 Figure 17. Main Jet Side View .................................................................................... M1 Figure 18. Main Nozzle Front View ............................................................................ M1 Figure 19. Main Nozzle Side View.............................................................................. M1 Figure 20. Rubber Replacement Ethanol Compatibility Table....................................... N1 Figure 21. EDS for Main Jet of Carburetor ................................................................... O1 Figure 22. EDS for Fuel Pump ..................................................................................... O1 Figure 23. Hydrocarbon and NOx Emissions ................................................................ Q1 Figure 24. CO and CO2 Emissions ................................................................................ Q2 Figure 25. Power curve for Tohatsu 5 hp four-stroke outboard engine .......................... R1 Figure 26. Power at Mid-Throttle ..................................................................................S2 Figure 27. Maximum RPM values ................................................................................ T1 Figure 28. Mid-throttle Fuel Efficiency ........................................................................ U2


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Tables Table 1. Toxicity of Gasoline for an adult male. Onset of toxic effects from 10-48 hours

of ingestion..............................................................................................................5 Table 2.Feedstocks, fuel energy to fossil energy ratio and future potential of the

renewability of ethanol. .........................................................................................13 Table 3. EPA Exhaust Emission Standards ....................................................................16 Table 4. CARB Exhaust Emission Standards.................................................................17 Table 5. Projected Price Range for Ethanol Sale in California .......................................22 Table 6. Projected Price Range for Ethanol Sale in California at Marinas ......................25 Table 7. Cold start solutions matrix ...............................................................................42 Table 8. Engine Specifications ......................................................................................44 Table 9. Gasoline Emissions Data .................................................................................46 Table 10. Jet Diameter Matrix .......................................................................................57 Table 11. Engine modification costs with and without labor. .........................................59 Table 12. Specifications Assessment .............................................................................60 Table 13. Comparison of Ethanol Fuel Properties to Gasoline ...................................... A1 Table 14. Alternative Fuels for Gasoline Marine Engines Matrix.................................. C1 Table 15. Budgetary cost for each expense ................................................................... V1 Appendices Appendix A. Comparison of Ethanol Fuel Properties to Gasoline ................................. A1 Appendix B. Project Timetable..................................................................................... B1 Appendix C. Alternative Fuels for Gasoline Marine Engines ........................................ C1 Appendix D. Summary of Material Safety Data Sheets for Gasoline and Ethanol ......... D1 Appendix E. Emission Regulations Plots...................................................................... E1 Appendix F. Production of Ethanol................................................................................F1 Appendix G. Historical Cost of Ethanol........................................................................ G1 Appendix H. Ethanol Fuel Calculations ........................................................................ H1 Appendix I. Fuel induction method for engines by major manufacturers........................ I1 Appendix J. Ethanol-compatible oil for two-stroke........................................................ J1 Appendix K. Efforts in Obtaining an Engine ................................................................ K1 Appendix L. 2000 Mercury 5 hp four-stroke outboard .................................................. L1 Appendix M. Additional Pro/E Drawings .................................................................... M1 Appendix N. Rubber and Ethanol Compatibility........................................................... N1 Appendix O. EDS Results ............................................................................................ O1 Appendix P. Cold-start Options .....................................................................................P1 Appendix Q. Idle Speed Emissions Testing .................................................................. Q1 Appendix R. Tohatsu Power Curve............................................................................... R1 Appendix S. Mid-throttle Power Testing .......................................................................S1 Appendix T. Maximum RPM Values............................................................................ T1 Appendix U. Efficiency at Mid-Throttle ....................................................................... U1 Appendix V. Project Budgetary Assessment ................................................................. V1


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I. Introduction

The project is a novel study on the merits of using ethanol to power recreational

boats and of how ethanol could be integrated into said application.

Need Statement

Due to the potential for environmental contamination by gasoline in recreational

boating, fuel ethanol is a potential solution to reduce pollution associated with

recreational boating.

Objectives

The deliverables of the project are:

• Assess and quantify the environmental impact associated with gasoline

use in recreational boating

• Assess and quantify the potential environmental benefits associated with

ethanol use in recreational boating

• Determine recommended strategy for introducing fuel ethanol into

recreational boating market

• Determine and implement modifications necessary to convert a four-stroke

outboard engine to run on ethanol

• Assess ethanol’s performance relative to gasoline to determine market

viability

• Disseminate results and conclusion for interested parties

Given these deliverables, the project was broken into two parts: the first term

focused upon the theoretical implications of using fuel ethanol, while the second term


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focused upon the actual modification and testing of an outboard engine to support these

findings. For a complete timetable of the project, see Appendix B.

II. Problem Background

Major strides have been taken to curtail the pollution load from the transportation

sector, primarily because of the accumulation of adverse effects in urban areas. With the

introduction of additives in gasoline, internal combustion engines now burn cleaner,

improving air quality for many urban areas across the country. However, these

improvements have been realized primarily in highway vehicles, while other sectors such

as recreational boating continue to operate with less advanced technology. Because of

these factors, other applications besides highway vehicles now constitute a

disproportionately high amount of the overall air pollution load. For example, air

pollution studies in Minnesota place recreational watercraft as the third major contributor

to air toxins in the state in 1999.1

Besides air pollution, recreational boating poses another serious threat to the

environment in the form of water pollution. Currently, lakes and rivers are vulnerable to

point and non-point sources associated with recreational boating. A point source (PS) is

a source of pollution that can be positively traced to a single polluter. In the case of

recreational boating, the engine itself is a point source. Many emissions are inherent in

the combustion process, but may also include direct spillage into the lake by humans,

tanks, and fueling stations. A non-point source (NPS) is a source of pollution, which is

indirectly introduced as pollutants are carried by rain or snowmelt. In recreational

boating applications, non-point pollution may also occur as fueling stations and careless

1 Minnesota Pollution Control Agency, June 2003 <http://www.pca.state.mn.us/air/toxics/toxics-graphs.html>


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boaters spill fuel on land, which inevitably enters the lake or river during precipitation

events. In fact, the Environmental Protection Agency (EPA) recognizes this potential

environmental hazard and has offered programs and grants to control the contribution

from non-point sources.2

Like highway vehicles, the current fueling infrastructure for recreational boating

is gasoline-centered. Because of this, water pollution concerns associated with

recreational boating are mainly functions of gasoline as a contaminant in the

environment. Therefore, fuel choice is a major consideration in reducing environmental

contamination in recreational boating applications. The project’s goal is to examine the

prospect of an alternate fuel, ethanol, to reduce the adverse environmental impact of

recreational boating. See Appendix C for a brief discussion of other alternative fuels and

the current state of the art for all alternative fuels in marine engines.

Case Against Gasoline

In order to fully understand how contamination caused by gasoline will affect the

environment, the physical properties of gasoline and its numerous components must be

investigated. Because gasoline is a mixture of various compounds, the effects of gasoline

contamination vary by source – both the mixture of hydrocarbons and trace chemicals in

gasoline and the fuel additives. Automotive gasoline is typically unleaded and, according

to a material safety data sheet from MFA Oil Company, is comprised mainly of two

parts. These are the gasoline component (up to 95%) and the benzene (balance)3, but may

also contain approximately 10% of an oxygenating additive.

2 US EPA, Polluted Runoff (Non-Point Source Pollution), August 2003 <http://www.epa.gov/owow/nps/> 3 MFA Oil Material Data Sheets, Unleaded Gasoline. <www.mfaoil.com/MSDS/MSDS%20Index.htm>


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Once introduced into the environment, the components can act differently and

must be taken into account to reduce the effects of gasoline contamination. Because

gasoline is a highly volatile liquid, the lighter components of gasoline may evaporate into

fumes and vapor, even at ambient temperatures. Because gasoline fumes and vapor are

typically heavier than air, the hazard of exposure to humans is high near spills and

confined spaces.4 Specific hazards of gasoline vapor fumes can include neurotoxic

effects, and prolonged exposure has caused kidney problems and liver tumors in

laboratory rats. Hazards on humans are thought to be similar, though testing and

documentation do not exist. Although the vapors tend to photodegrade once in the air,

the potential hazard of the fumes to humans is relatively high, as most gasoline spills are

caused by humans and within close proximity to humans.

Once in contact with water, the lighter components may remain on the water

surface. As these components are generally lighter than water, the components will

remain at the water surface during calm weather. To accurately assess how gasoline will

behave once introduced in water, various factors must be taken into consideration,

including the amount spilled, the terrain of the lake, and the weather5. Human health

effects from skin contact can vary from skin irritation to kidney damage. From ingestion,

effects can vary from lung and liver damage and coma6. Gasoline is a known carcinogen.

Further information on toxicity for gasoline is found in Appendix D.

4 Material Safety Data Sheet-Chevron, Regular Unleaded Gasoline <http://library.cbest.chevron.com/lubes/chevmsdsv9.nsf/0/8002e031e024ef378825620c 000c2616?OpenDocument> 5 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000 6 MFA Oil Material Data Sheets, Unleaded Gasoline. <www.mfaoil.com/MSDS/MSDS%20Index.htm>


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Dose 5-10 ml to 18 ml 18+ ml 27-40 ml 26-76 ml 60-240 ml 115-

470ml Toxic Effects

Burning of GI tract,

abdominal pain

Burning of GI tract,

abdominal pain

As above Fever, convulsions,

unconsciousness

As above As above Normal fatal dose (much smaller if inhaled)

Table 1. Toxicity of Gasoline for an adult male. Onset of toxic effects from 10-48 hours of ingestion.

Source: O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000

Although gasoline is thought to biodegrade relatively quickly in the environment

(12-48 hours), this is highly dependent on whether the specific lake has biota able to

biodegrade the material. In fact, gasoline may persist in the environment for several

times longer if such biodegraders are not present. If biodegraders do exist, large spills

may render water anoxic, or deprived of oxygen, which can be detrimental to organisms

depending on the size of the spill. In addition, some components may degrade while

other non-degraded components persist in the water column.

A component in gasoline, benzene, is a contaminant that can be harmful in both

vapor and liquid phases. Benzene is a known carcinogen and has high potential to cause

kidney and liver damage. Because of this, benzene is highly monitored by the EPA for

drinking water quality7. Estimates on benzene biodegradation range from two days to

two weeks in water, and up to 17 days in air, depending on the season.

Recently, oxygen-containing chemicals were added to gasoline for cleaner

combustion, therefore decreasing air emissions. In the event of a spill, these additives

must also be considered as a potential health hazard. Currently, the fuel additive methyl

tertiary butyl ether (MTBE) is under much scrutiny due to its proposed effects on human

health. MTBE and its effects are important to consider due to its multi-faceted nature of

7 US EPA, Groundwater and Drinking Water, Technical fact sheet: benzene, Nov. 2002 <http://www.epa.gov/OGWDW/dwh/t-voc/benzene.html>


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exposure to humans. MTBE can be inhaled as a gas, ingested if it spreads to contaminate

groundwater, or even absorbed through the skin. Although the effects to human health

are still currently being tested8, MTBE contamination from gasoline has been highly

scrutinized; many states9, such as Colorado and California, have aggressively pursued

strict regulations of MTBE and the addition of ‘cleaner’ additives10. In fact, regulations

on drinking water have further reduced MTBE threshold amounts and have lead to a ban

of MTBE in California, and the discussion of a nationwide ban.

MTBE is a contaminant of interest because it readily dissolves into water, up to

30 times more than other petrochemicals in gasoline. Because of this, the MTBE in

gasoline can contaminate large volumes of water (one gallon of MTBE can contaminate

four million gallons of water11) and can remain and travel through water systems. Also

volatile, MTBE may find its way into the atmosphere, though MTBE photodegrades

quickly in the atmosphere with ultraviolet light. Unfortunately, its high solubility in

water prevents this method of degradation and allows it to enter the anthropogenic water

cycle, where potential for human exposure is drastically increased. These properties of

MTBE make gasoline spills a paramount concern, especially in lake areas.

When combusted in an engine, gasoline has many pollutant byproducts of

interest. Among the most important are carbon monoxide (CO), oxides of nitrogen

(NOx), carbon dioxide (CO2), and particulate matter with diameters of 2.5 micrometers

(PM2.5) and 10 micrometers (PM10). In an outboard engine air emissions are an important 8 Gilbert M. Masters, Introduction to Environmental Engineering Second Edition (New Jersey: Prentice Hall, 2001) 375 9 Nancy E. Kinner, Testimony before the U.S. Senate Committee on Environment and Public Works, University of New Hampshire, April 23, 2001 10 US EIA, Status and Impact of MTBE bans, March 2003 <http://www.eia.doe.gov/oiaf/servicerpt/mtbeban/table1.html> 11 Nancy E. Kinner, Testimony before the U.S. Senate Committee on Environment and Public Works, University of New Hampshire, April 23, 2001


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consideration, not only for their impact on air quality, but also because the absence of a

muffler causes air emissions to be injected into the water. Therefore, reductions in air

emissions may significantly reduce the impact on water quality as well.

Carbon monoxide is a colorless and odorless poisonous gas, which is produced

when gasoline is burned in less optimal conditions. The resultant carbon monoxide gas

poses a major health hazard to humans. As an asphyxiant, carbon monoxide gas retards

the body’s ability to transport oxygen to parts of the body12. Because of this, even small

quantities of carbon monoxide in the air can have much larger secondary effects, due to

hemoglobin’s high affinity for CO (up to 210-250 times that of oxygen13). Carbon

monoxide poisoning and death during recreational boating activity is not uncommon; the

National Institute for Occupational Health and Safety is aware of 106 CO poisonings

specific to recreational boating14

Another set of pollutants, the oxides of nitrogen, are of concern to gasoline

combustion in recreational boating. These compounds are the result of nitrogen

oxidation, namely when nitrogen is oxidized in the combustion air under high

temperatures or oxidized in gasoline itself. Nitric oxide (NO), which often constitutes the

majority of nitrogen oxide pollutants, can react with oxygen in air to produce nitrogen

dioxide (NO2), a known human health hazard. When inhaled, the gas can often cause

lung irritation as well as bronchitis and pneumonia.

12 Gilbert M. Masters, Introduction to Environmental Engineering Second Edition (New Jersey: Prentice Hall, 1998) 343-344. 13 US Dept. of Health and Human Services. “Carbon Monoxide Emissions and Exposures on Recreational Boats Under Various Operating Conditions” Feb. 2003 <safetynet.smis.doi.gov/Report%20171-05ee2.pdf> 14 US Dept. of Health and Human Services. “Carbon Monoxide Emissions and Exposures on Recreational Boats Under Various Operating Conditions” Feb. 2003 <safetynet.smis.doi.gov/Report%20171-05ee2.pdf>


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NOX emissions also have lasting secondary effects. Once in the atmosphere, it

can react with OH, a hydroxyl radical, to form nitric acid, which is a contributor to the

problem of acid rain. Its effects can also be seen in the reddish-brown smog over

urbanized areas, such as Los Angeles. When able to react with other pollutants, such as

evaporated hydrocarbons and other volatile organic compounds (VOCs) and with

sunlight, oxides of nitrogen can form secondary pollutants called photochemical oxidants.

Among these are ozone (O3), which is damaging to human health and vegetation, and eye

irritants such as formaldehyde (HCHO)15. Ozone levels can become a problem in

localized areas, such as Lake Tahoe, where ozone levels are affecting surrounding plants

and organisms16. Like carbon monoxide, nitric oxide and nitrogen dioxide have been

major targets of reductions in air quality policy due to the direct and secondary adverse

health effects.

Carbon dioxide is an important element in emissions because of its contribution to

the greenhouse effect. Though the notion that rising carbon dioxide in the atmosphere is

causing global warming is still under question17, carbon dioxide and greenhouse gases

have been major targets in recent international environmental policy, as seen in the Kyoto

Protocol18. Although not as immediate of a consideration when considering impacts on

human health and the environment from boating, the overarching effects of carbon

dioxide as an emission are still viable concerns when considering emissions from a more

general stand point. 15 Gilbert M. Masters, Introduction to Environmental Engineering Second Edition (New Jersey: Prentice Hall, 1998) 344-345 16 US Water News Online, “Experts study effects of Sacramento pollution on Lake Tahoe” Sept 2003. <http://www.uswaternews.com/archives/arcquality/3expstu9.html> 17 Gilbert M. Masters, Introduction to Environmental Engineering Second Edition (New Jersey: Prentice Hall, 1998) 477 18 Government of Canada, Canada and the Kyoto Protocol, July 2001, viewed 10/17/03 <http://www.climatechange.gc.ca/english/whats_new/overview_e.html>


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Particulate matter is a general health concern because it can cause respiratory

illness. The EPA currently regulates the load in air19, and trends have shown steady

decreases over the last decade. PM2.5 and PM10 can be a result of the combustion process,

but may also be formed from secondary reactions from NOX and SO2.

In response to these considerations, the altering of ordinary gasoline fuels has

been suggested as one method to reduce such pollution. The process of oxygenating

gasoline allows for a ‘cleaner’ burning process, which results in cleaner emissions. One

fuel of interest is ethanol20. Recently, ethanol has become an additive in gasoline to

reduce the negative effects on seasonal air quality.

One last consideration in fuel choice is renewability and sustainability. Gasoline

is a petroleum-derived product, and as with any fossil fuel derivative, the lifetime of

gasoline is limited.

III. Case for Ethanol

The objective of the project was to examine ethanol’s use as fuel in recreational

boating. Although other energy sources have been implemented into boating

applications, ethanol provides unique benefits to recreational boating. A discussion of

the alternatives can be found in Appendix C.

Ethanol is a simple grain alcohol, commonly found in alcoholic beverages. With

its long history of human consumption, the hazards of ethanol to human health and the

environment are well understood and perceived to be much less than with gasoline. In

19 US EPA, Air trends summary: PM-10. April 2002. <http://www.epa.gov/air/aqtrnd95/pm10.html> 20 William W. Nazaroff and Lisa Alvarez-Cohen, Environmental Engineering Science, (New York: John Wiley & Sons, Inc, 2001) 282


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fact its toxicity is much less than that of gasoline for humans21 (additional toxicity data

for ethanol are found in Appendix D). Further, a report by the Governors’ Ethanol

Coalition concluded that ethanol poses no threat to ground or surface water, and is

expected to biodegrade rapidly in all environments22. On a fundamental level, ethanol is

comprised of far fewer components than the hundreds of chemicals, some carcinogenic,

of which gasoline is comprised23. This implies a simpler fate and transport process and

remediation for ethanol than for gasoline.

Unlike gasoline, which depends heavily on a specific type of organism for

biodegradation, ethanol is naturally occurring and is readily biodegradable. Estimates for

biodegradation half-life range from 0.5-5.0 days in vapor form and 0.1-2.1 days in

surface water24. This can vary significantly depending on season and terrain, as with

gasoline, but the ranges of biodegradation times are lower for ethanol, implying more

biodegradability than gasoline in similar conditions.

Although solubility in water can pose a potential threat in the case of toxic

chemicals, ethanol is relatively non-toxic, and its infinite solubility in water allows for

ethanol to be readily diluted to non-toxic levels25. Along with biodegradation comes the

potential for anoxia in water. However, because of the stratified aspect of lakes, spills

can often be contained at the surface where decreased oxygen levels will be localized,

21 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 22 Governors’ Ethanol Coalition, “Fate and Transport of Ethanol-Blended Gasoline in the Environment” Oct. 1999 23 Conversation with Professor Benoit Cushman-Roisin Dec. 12, 2003 24 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 25 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000.


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minimizing effects to the lake as a whole. In the case of spills in more turbulent water

(e.g. a river), this is not as large of a concern, as oxygen-rich water is always in supply.

The vast disparity in toxicity levels between ethanol and petroleum-based fuel is

illustrated in the March 1, 2004 tanker explosion off the coast of Virginia. The tanker

was carrying 3.5 million gallons of industrial ethanol; however, according to a U.S. Coast

Guard spokesman, “the 700 tons of fuel oil carried by the tanker [were] a greater cause

for concern than the ethanol.”26

The change in human health effects is said to be minimal with the addition of

ethanol, as the oxygenate is relatively non-toxic in comparison to gasoline27. However,

recent research indicates that when ethanol is blended with gasoline, ethanol may be

‘preferentially’ biodegraded over compounds found in gasoline. This is most likely due

to the absence of biodegrading organisms. In such an instance, ethanol would readily

biodegrade, while compounds, such as BTEX (benzene, toluene, ethylbenzene, and

xylene), are allowed to continue fate and transport processes. Furthermore, ethanol in

gasoline may, in fact, increase BTEX plumes in groundwater28. Though research is

currently trying to justify these claims, ethanol-gasoline blends may not be a proper

alternative to eliminating the potential harms from using gasoline, because of these

deleterious effects resultant from this type of fuel blending.

According to Dr. Charles Wyman, former director of the Center for Renewable

Fuels and Biotechnology at NREL, “ethanol is low in toxicity, volatility, and

26 Tanker Carrying Ethanol Explodes and Sinks off of U.S. Coast, 2004, United Nations Foundation, 5 March 2004, <http://www.unwire.org/UNWire/20040301/449_13567.asp>. 27 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 28 Powers, Susan, et al. “Transport and fate of ethanol and BTEX in groundwater contamination by gasohol” 2000.


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photochemical reactivity, resulting in reduced ozone formation and smog compared to

conventional fuels.” 29 Although the potential for a reduction in air emissions is apparent,

little data exist for recreational boating. However, the addition of ethanol as a blending

fuel in gasoline and the benefits on air emissions are documented for automobiles. In one

study, with the introduction of ethanol up to 10% (E10), significant reductions were

realized in particulate matter and carbon monoxide emissions30. Further, reductions were

seen in CO2 emissions as well as overall fuel consumption in some of the vehicles tested.

No significant change was found for NOX emissions. In another study with a blended

gasoline with up to 85% ethanol (E85), reductions were seen in NOX and CO2 emissions,

with increases in CO and hydrocarbons. In general, lower proportions of ethanol tend to

decrease criteria pollutants in the combustion process. But, as the proportion of ethanol

becomes higher, emissions can increase due to inefficient burning because engines are

designed to run on gasoline and are not tuned for ethanol. In the case of recreational

boats, a similar trend is expected, as engines are built to run primarily on gasoline, until

the technology seen in automobiles can be adapted to recreational boating applications.

Although variant on actual engine design, the EPA expects a 15% reduction in

ozone-forming VOCs, a 40% decrease in CO emissions, a 20% decrease in PM, and a

10% decrease in NOX31 for E85 fuel, and presumably more for E95 or pure ethanol.

Critics of ethanol as a fuel often point to emissions increases to deter ethanol usage; the

use of ethanol in a combustion engine may also increase the acetaldehyde emissions32.

29 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 30 AEA Technology. “Ethanol Emissions Testing” March 2002. 31 US EPA ethanol fact sheet, Mar 2002 <http://www.epa.gov/otaq/consumer/fuels/altfuels/altfuels.htm#fact>. 32 M. L. Poulton, Alternative Fuels for Road Vehicles (Boston: Computational Mechanics Publications, 1994).


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However, a study by the California Environmental Policy Committee found that although

acetaldehyde emissions were greater in ethanol fueled engines, emissions of more toxic

compounds such as formaldehyde were also reduced, offsetting the slight increase found

in acetaldehyde33.

In terms of the future of the fuel, ethanol is renewable and is more sustainable

than gasoline. The potential for sustainability is high as research is currently underway to

make ethanol from various forms of plant biomass. Thus, the implementation of ethanol

in recreational boating may not only increase the environmental performance of outboard

engines from a water and air pollution standpoint, but also decrease the overall demand

for gasoline. This implementation may catalyze the introduction of other alternative

energies to further increase energy sustainability as a whole.

Current Feedstocks Fuel Energy: Fossil Energy Future Potential Usually corn in US, but any

sugar crop can be used. 1.25:1 (all production

energy assumed to be fossil based

Non-corn bioethanol may offer higher energy

efficiency. Woody biomass may also be a future stock.

Table 2.Feedstocks, fuel energy to fossil energy ratio and future potential of the renewability of ethanol.

Fuel energy: Fossil energy gives the ratio of energy contained in the fuel as compared to the fossil fuel energy required to create/support the given fuel through its life cycle. Adapted from: O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. Aquatic Toxicity Analysis

According to Benoit Cushman-Roisin, professor in environmental engineering at

Dartmouth College, ethanol is less detrimental to aquatic environments than gasoline34.

To verify this, a simple analysis is presented in order to compare the environmental

33 Renewable Fuels Association, “Ethanol and the Environment” <http://www.ethanolrfa.org/factfic_envir.html> 34 Conversation with Prof. Benoit Cushman-Roisin. Dec. 12, 2003


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performance of each fuel in water. A hypothetical scenario of a spill of 50 kg will be

assessed for both gasoline and ethanol. Assuming some lake surface area of 1 km2, and

an effective mixing depth of 10 m (due to a seasonal thermocline), it can be assumed that

the effective mixing volume will be a product of one half the length and width of the lake

surface (area = 250,000 m2) and the depth, or 2,500,000 m3. If 50 kg of gasoline is

spilled and mixed into the given water volume, the gasoline concentration in the water

will be 20 micrograms per liter, the aquatic toxicity threshold for gasoline in water35. In a

similar situation, 50 kg of ethanol spilled and mixed, the aquatic toxicity does not exceed

the threshold of 14,760 micrograms per liter36. It is clear that an equivalent spill of

ethanol would have far less ecological effects on the aquatic life than in the event of a

gasoline spill. This scenario is a generalization, but gives insight on the impacts of each

fuel on the environment.

IV. Specific Focus: California

The United States does not have uniform fuel prices and environment regulations;

therefore, a specific area needs to be chosen as a case study to better understand the

feasibility of introducing fuel ethanol into recreational boating.

Case for California

California was chosen as the state to focus the study for a number of reasons.

California has the second highest number of boats in the United States, so there is a large

target market. Additionally, one of the primary concerns of ethanol's use as a fuel was its

price, which is typically higher than gasoline. California, with one of the highest

35 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000. 36 O’Keefe, Michael, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake” 2000.


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gasoline prices in the country, could provide a market where ethanol prices could be

competitive with gasoline. However, the most important reason for targeting California

has to do with their tough environmental regulations and support of alternative fuels.

California has the toughest emissions regulations in the country; in fact all outboard

engines are rated not just on EPA regulations, but also California Air Resource Board

regulations. Additionally, California has more alternative fuel stations than any other

state in the U.S.37 Most alternative fuel technologies get their start in California; when

major automakers produce alternative fueled or electric vehicles, the first test market is

almost always in California. In conclusion, California represents the most supportive

environment for introducing ethanol-powered boat engines, and would hopefully allow

the technology to become established before expanding nationwide.

Environmental Regulations

The United States began to work to lower water and air pollution through the

Environmental Protection Agency (EPA) with the 1970 Clean Air Act38 and 1977 Clean

Water Act39. Through the intermittent years the regulations have become more stringent

and specific. Now, there are established federal air pollution control standards for

recreational boats using gasoline-powered outboard engines.

The Federal Water Pollution Control Act prohibits the discharge of oil or

hazardous substances into US waterways. This includes “any discharge that produces a

film or discoloration of the surface of the water or causes a sludge or emulsion beneath

37 Alternative Fuels Data Center, Alternative Fuel Station Counts Listed by State and Fuel Type (Dept. of Energy 1 Dec. 2003, <http://www.afdc.doe.gov/refuel/state_tot.shtml>. 38 The Plain English Guide to the Clean Air Act, 1993, EPA – Air Quality and Standards, 28 Nov. 2003, <http://www.epa.gov/oar/oaqps/peg_caa/pegcaain.html>. 39 The Clean Water Act, 2003, EPA – Laws and Regulations, 28 Nov. 2003, <http://www.epa.gov/region5/water/cwa.htm>.


16

the surface of the water.”40 The current exhaust emissions standards are applicable to

new marine spark-ignition outboard and personal watercraft engines beginning with the

1998 model year. The EPA only regulates hydrocarbon and nitrogen oxide emissions.

Hydrocarbon Plus Oxides of Nitrogen Exhaust Emission Standards [grams per kilowatt-hour]

Model year P < 4.3 kW HC+NOX P ≥ 4.3 kW HC+NOX

1998 278.00 (0.917 x (151 + 557/ (P0.9)) + 2.44

1999 253.00 (0.833 x (151 + 557/ (P0.9)) + 2.89

2000 228.00 (0.750 x (151 + 557/ (P0.9)) + 3.33

2001 204.00 (0.667 x (151 + 557/ (P0.9)) + 3.78

2002 179.00 (0.583 x (151 + 557/ (P0.9)) + 4.22

2003 155.00 (0.500 x (151 + 557/ (P0.9)) + 4.67

2004 130.00 (0.417 x (151 + 557/ (P0.9)) + 5.11

2005 105.00 (0.333 x (151 + 557/ (P0.9)) + 5.56

2006 and later 81.00 (0.250 x (151 + 557/ (P0.9)) + 6.00

Where P = the average power of an engine in the model year in kW Table 3. EPA Exhaust Emission Standards41

The emissions standard that corresponds to the 2006 and later model years is commonly

referred to as the “EPA 2006 Standards.” The federal regulations are intended to reduce

HC + NOx emissions from outboard and personal watercraft engines by 75 percent by

2025.42

40 Pollution Regulations, 2003, US Coast Guard, 30 Nov. 2003, <http://www.uscgboating.org/safety/fed_reqs/equ_pollution.htm>. 41 Control of Air Emissions from Marine Spark-Ignition Engines, 2003, EPA – Air Programs, 31 Oct. 2003, <http://ecfrback.access.gpo.gov/otcgi/cfr/otfilter.cgi?DB=3&query=40000000091&region=BIBSRT&action=view&SUBSET=SUBSET&FROM=1&SIZE=10&ITEM=1#Sec.%2091.101>. 42 Emission Standards and Test Procedures for New 2001 and Later Model Year Spark-Ignition Engines, 1999, Air Resources Board, 25 October 2003, <http://www.arb.ca.gov/regact/marine/fsor.pdf>.


17

Because the federal program is not sufficient to meet California’s State

Implementation Plan (SIP) requirements or air quality goals, a more progressive program

was necessary. California’s exhaust emission allotments are much lower – as the EPA

2006 Standards are at the lowest tier. The emission standards – as determined by the

California Air Resources Board (CARB) – are applicable to new 2001 and later year

models of spark-ignition marine engines.

Hydrocarbon Plus Oxides of Nitrogen Exhaust Emission Standards

[grams per kilowatt-hour] Model year P < 4.3 kW HC+NOX P ≥ 4.3 kW HC+NOX

2001 81.00 (0.250 x (151 + 557/ (P0.9)) + 6.00

2004 64.80 (0.20 x (151 + 557/ (P0.9)) + 4.80

2008 30.00 (0.09 x (151 + 557/ (P0.9)) + 2.10

Where P = the average power of an engine in the model year in kW Table 4. CARB Exhaust Emission Standards43

In addition, no new spark-ignition marine engines may be produced for sale to replace

spark-ignition marine engines in pre-2001 model year equipment after the 2004 model

year, unless those engines comply with the 2001 model year emission standards.44 For a

graphical representation of the emission standards, see Appendix E. To facilitate sale of

outboard engines in California, CARB has implemented engine labels45 based upon the

emission standards:

One Star - Low-Emission • meets the Air Resources Board’s 2001 exhaust emission standards • 75% lower emissions than conventional carbureted two-stroke engines • equivalent to the U.S. EPA’s 2006 standards

43 Air Resources Board, California Exhaust Emissions Standards and Test Procedures for 2001 Model Year and Later Spark-Ignition Marine Engines (1999) 4. 44 Air Resources Board, California Exhaust Emissions Standards and Test Procedures for 2001 Model Year and Later Spark-Ignition Marine Engines (1999) 5. 45 California Code of Regulations, Chapter 9 Off-Road Vehicles and Engines Pollution Control Devices, section 2443.3 3.


18

Two Stars - Very Low Emission • meets the Air Resources Board’s 2004 exhaust emission standards • 20% lower emissions than One Star - Low-Emission engines

Three Stars - Ultra Low Emission • meets the Air Resources Board’s 2008 exhaust emission standards • 65% lower emissions than On Star - Low Emission engines

The CARB regulations will dually result in a reduction of water pollution.46 In

addition to very strict exhaust emission standards, California has implemented strategies

to lessen the water pollution issues caused by gasoline-powered engines. MTBE – an

additive – has been banned and was phased out by December 31, 2003. Some large lakes

such as Lake Tahoe, Echo Lake, Cascade Lake, and Fallen Leaf Lake47 have taken a

more direct route by prohibiting the use of carbureted two-stroke boat engines,

implemented by Tahoe Regional Planning Agency48. Only two-stroke direct injection

and four-stroke engines are permitted on the lakes. These regulations hope to further

protect the environment from the harmful effects of the outboard engine emissions.

Infrastructure for introducing ethanol as a fuel in California

As stated earlier, MTBE has been banned as a fuel oxygenate in California. The

phase-out of MTBE and substitution of ethanol (the only approved substitute by the

California Environmental Policy Council) was complete by the end of 2003 and makes

California the United States’ largest market for ethanol fuel.49 This infrastructure would

only need to be appended in order to supply marinas with ethanol as a fuel for boats.

46 New Regulations for gasoline marine engines, 1999, Air Resources Board, 12 Nov. 2003, <http://www.arb.ca.gov/msprog/marine/facts.pdf>. 47 A Consumer’s Guide to Lake Tahoe, Tahoe Regional Planning Agency, 12 Nov. 2003, <http://www.dbw.ca.gov/Pubs/Blt/>. 48 A Consumer’s Guide to Lake Tahoe, Tahoe Regional Planning Agency, 12 Nov. 2003, <http://www.dbw.ca.gov/Pubs/Blt/>. 49 California Energy Commission, Ethanol Supply Outlook for California (2003) 1.


19

The infrastructure takes into account ethanol production and supply, ethanol

transportation to California markets, and ethanol storage and distribution within

California – resulting in a retail price for ethanol.

In 2004, California is expected to require between 760 and 990 million gallons of

ethanol for gasoline blending. In the next few years, the majority of the ethanol needs

would be satisfied by domestic ethanol producers with no more than 10% coming from

foreign sources such as Brazil. Most of the domestic ethanol is made from corn in the

Midwest. Between 2001 and 2003, the United States’ ethanol production grew by 38% -

an increase of 870 million gallons per year – from 2.22 to 3.07 billion gallons of ethanol.

The number of operating ethanol plants increased from 57 to 69. There are 16 new

facilities under construction that would 767 million gallons to the total capacity by the

end of 2006. In addition, 50 projects are planned that would increase the capacity by 2

billion gallons at the close of 2006.50 There have also been discussions of expanding

California’s ethanol production through conventional corn-to-ethanol projects, sugarcane-

to-ethanol projects, and waste biomass-to-ethanol projects.51 For an explanation of the

various methods of producing ethanol, see Appendix F. The supply of ethanol will be

able to handle the increased demand introduced by the California ban of MTBE.

50 California Energy Commission, Ethanol Supply Outlook for California (2003) 2. 51 California Energy Commission, Ethanol Supply Outlook for California (2003) 11.


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Figure 1. USA Ethanol Production Capacity52

The next step is to transport and distribute the fuel ethanol. Because of the large

distance between the Midwest and California, only two transportation methods are viable

– rail shipments and marine cargoes, although pipelines53 are being considered. Rail

shipments normally consist of one of more 30,000-gallon rail cars, filled about 97%.

Two to three weeks would be needed for transit from the Midwest to California –

resulting in about four to six weeks for one complete turnaround. Marine cargoes of

multiple 10,000-barrel river barges would travel down the Mississippi River through the

Panama Canal to the California Pacific Coast – taking a minimum of 34 days. Shipments

could range from 1 to 12 million gallons, although 4-5 million gallons would be more

typical. It is important to note that 1.2 to 1.7 million gallons of MTBE per day is shipped

52 California Energy Commission, Ethanol Supply Outlook for California (2003) 7. 53 Ethanol and Market Opportunities, 2000, RFA, 1 Nov. 2003, <http://www.ethanolrfa.org/factfic_market.html


21

from the gulf coast to the west coast, and this capacity could be redirected for ethanol

transportation. There is no significant economic advantage for using one of the methods

over the other, so the location of the ethanol plant would be the deciding factor.54 Once

the ethanol arrives in California, it would be redistributed via truck or rail to centrally-

located final destination terminals, where it would be blended with gasoline before being

redistributed to gas stations for sale.

The retail price of ethanol must include the production and transportation costs as

well as any relevant taxes. Its production costs are governed by the price of corn, which

has an effect on production volume, as the product must be priced to compete based upon

its value to the end user. The cost of shipping ethanol to California would cost between

14 and 17 cents per gallon and the handling charges at the central terminals would be in

the range of $0.006 to $0.017 per gallon. The minimum premium required to draw

ethanol from the Midwest octane market to California is five cents per gallon.55 The

current production cost of ethanol in Nebraska is $1.02 per gallon of ethanol.56 For a

look at the historical cost of fuel ethanol, see Appendix G. In addition, there is taxation.

Although California does not provide a formal tax exemption for ethanol, it does have an

excise tax rate of only $0.09 per gallon for 85% blends and above, as opposed to the

$0.18 per gallon tax on gasoline.57 The final component is the mark-up at the pump,

54 Downstream Alternatives, Inc., The Renewable Fuels Association, The Use of Ethanol in California Clean Burning Gasoline – Ethanol Supply/Demand (1999) 11-12. 55 Downstream Alternatives, Inc., The Renewable Fuels Association, The Use of Ethanol in California Clean Burning Gasoline – Ethanol Supply/Demand (1999) 31. 56 Mark Yancy, The Investment Climate for Ethanol Production in California, 2003, BBI, 29 Nov. 2003, <http://www.bbiethanol.com/doe/ca/Yancey-CA-DOE.pdf>. 57 Tax Rate on Ethanol or Methanol, 2003, Database of State Incentives for Renewable Energy, 29 Nov. 2003, <http://www.dsireusa.org/library/includes/incentive2.cfm?Incentive_Code=CA24F&state=CA&CurrentPageID=1>.


22

which is typically 10 to 22 cents for gasoline, and will be assumed to be the same for

ethanol sales in California.58

Price Range for California Ethanol

(per gallon of ethanol) Production Cost $1.020 ─ $1.020 Price Incentive $0.050 ─ $0.050 Transportation/handling costs $0.146 ─ $0.187 Excise Tax Rate $0.090 ─ $0.090 Mark-up $0.100 ─ $0.220 Projected California Price Range $1.406 ─ $1.567 Gasoline Equivalent Price Range $1.223 ─ $2.366 Table 5. Projected Price Range for Ethanol Sale in California

The price is not expected to exceed $2.366 per gallon, which although high is still

comparable to the statewide average for regular gasoline at $1.691 as of 24 November

2003.59

A similar approach will need to be taken to evaluate the potential consumption

and price of ethanol in recreational boating applications on lakes. According to the US

Coast Guard, California had the second most boats in use in 2000 with 904,863 registered

boats behind only Michigan.60 Of those boats, 350,039 of them used outboard engines.61

According to the California Department of Boating and Waterways62, the

Recreational Boat Building Industry63, the Recreational Boating and Fishing

Foundation64, the Energy Information Administration65, and the U.S. Department of

58 John Cruger-Hansen, “Re: fuel docks,” email to the author, 15 Nov. 2003. 59 Transportation Fuels: Gasoline, Diesel, Ethanol, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/index.html>. 60 US Department of Transportation, United States Coast Guard, Boating Statistics – 2000 (2000) 24. 61 US Department of Transportation, United States Coast Guard, Boating Statistics – 2000 (2000) 25. 62 Department of Boating and Waterways, 2003, California, 4 Nov. 2003, <http://www.dbw.ca.gov/index.htm>. 63 Power Boat Industry Statistics, Recreational Boat Building Industry, 7 Nov. 2003, <http://www.rbbi.com/desks/mkt/stats/stats.htm>. 64 Stephanie Hussey, “Ethanol as a fuel for recreational boating,” email to the author, 19 Nov. 2003. 65 Curley Andrews, “RE: gasoline consumption in boats,” email to the author, 17 Nov. 2003.


23

Transportation – Bureau of Transportation Statistics66, no surveys have been taken on the

national or California level that differentiate between the number of two-stroke and four-

stroke outboard engines currently used recreationally. A survey was conducted by the

Wisconsin Department of Natural Resources and the University of Wisconsin Survey

Center for boats registered in Wisconsin in order to determine a gasoline consumption

estimate for recreational boating in 2000. The survey found that the average estimate of

gasoline consumption for Wisconsin boaters was 58.69 gallons in 200067 and that 20% of

the boaters had four-strokes, 12% did not know, and the remainder had two-strokes.68

For the purpose of this study, it will be assumed that the information is the same for

California; therefore, there were 70,008 four-stroke outboard engines in use in California

in 2000.

The 70,008 four-stroke engines consumed 4,108,770 gallons [70,008 x 58.69] of

gasoline in 2000 at a rate of 1.58 gallons per hour.69 There are generally two ways to

relate a volume of gasoline to a volume of ethanol – the energy content of the fuel and

having an engine optimized for the specific fuel. The energy content of gasoline is

115,000 Btu/gal, where as ethanol has an energy content of 76,100 Btu/gal.70 This results

in 1.51 gallons of ethanol being equivalent to one gallon of gasoline. On the other hand,

if the engine were optimized to run on ethanol, there would be a 15% efficiency

improvement over gasoline71 – corresponding to 0.87 gallons of ethanol being equivalent

66 Answers, “RE: gasoline consumption in boats,” email to the author, 17 Nov. 2003. 67 Eugene Lange, “Gasoline Consumption Estimate for the 2000 Recreational Boating Survey,” State of Wisconsin – Department of Natural Resources. 2002. 68 Edward Nelson, “RE: gasoline consumption in boats,” email to the author, 20 Nov. 2003. 69 Tahoe Regional Planning Agency, Environmental Assessment for the Prohibition of Certain Two-Stroke Powered Watercraft (1999) 10. 70 Wyman, C.E. 2003. Subject Area: Renewable and Alternative Sources. unpublished. 5-6. 71 Michael O’Keefe, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake,” Thesis, University of Washington, 2000, 105.


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to one gallon of gasoline. If all of the four-stroke outboard engines replaced gasoline

with ethanol, 3.57 million [optimized engine] to 6.20 million gallons [energy content] of

ethanol would be required. Mentioned earlier, the United States expects to have the

capacity to produce approximately 4 billion gallons of fuel ethanol in 2004. Adding the

ethanol needed to replace MTBE to the values just calculated would result in California

requiring approximately 764 million to 996 million gallons of ethanol in 2004. This is

not a significant increase from the supply needed to replace MTBE; therefore, there will

be an adequate supply of ethanol to meet all of California’s needs. See Appendix H for

the aforementioned calculations.

Ethanol is already being transported to California and distributed within the state.

The only additional cost considerations are those that deal directly with selling fuel on a

lake. Marine fuel docks have significantly higher operating costs than land-based gas

stations. Waterfront property commands a much higher price than regular roadside

property that houses regular gas stations, resulting in higher mortgage payments. The

environmental regulations are stricter because anything spilled immediately enters the

water. Accordingly, there must be a large amount of spill cleanup gear and the

employees must have training equivalent to HAZWOPPER (OSHA’s hazardous waste

operations and emergency response protocol) in order to use the spill gear. Finally,

marina fuel docks have limited operating seasons and hours so the sales volume is

generally less than a regular gas station. The 35 cents per gallon attempts to compensate

for the higher operating costs.72 It is assumed that similar operating costs would be

required for ethanol to be dispensed at marinas. The spill preparation would most-likely

be relaxed, but added costs would be required to convert the fuel pump to carry ethanol. 72 John Cruger-Hansen, “Re: fuel docks,” email to the author, 15 Nov. 2003.


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Price Range for California Ethanol Sold at Marinas

(per gallon of ethanol) Production Cost $1.020 ─ $1.020 Price Incentive $0.050 ─ $0.050 Transportation/handling costs $0.146 ─ $0.187 Excise Tax Rate $0.090 ─ $0.090 Mark-up $0.350 ─ $0.350 Projected California Price Range $1.656 ─ $1.697 Gasoline Equivalent Price Range $1.441 ─ $2.562

Table 6. Projected Price Range for Ethanol Sale in California at Marinas

The price is not expected to exceed $2.562 per gallon of gasoline, which is still

comparable to the statewide average for regular gasoline at $1.991 – adjusted for

lakeshore consumption from 6/16/03 to 9/15/03.73 See Appendix H for the adjustment

calculation.

A major obstacle for introducing fuel ethanol into marine applications involves

the necessary modifications to the existing fueling facilities. With blends of 85% ethanol

and greater, many parts would need to be replaced.

The pumps, hoses, nozzles, safety breaks, swivels, and all internal metal parts touching the fuel must be made of certain materials that withstand this toxic blend of chemicals. In this case, the recommended materials for the metal are 'stainless steel' or 'nickel-plated steel' (both items make the cost of the equipment more than double and often go up by 250% to 500%). Even with these two materials, manufacturers most often will not warranty any equipment more than 30 to 90 days if used with ethanol blends.74

Gasboy, a division of Gilbarco, is the only manufacturer of pumps for 85% and higher

ethanol blended fuel; Gilbarco has discontinued this line of products while researching

them further. Tuthill (Fill-Rite) and Great Plains Industries are investigating

manufacturing pumps for this application. Tuthill (Fill-Rite) does have pumps

73 2003 Unleaded Gasoline Statewide Averages, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/retail_gasoline_prices.html#2003>. 74 Donlee Pumps, “Re: ethanol storage in marinas in CA,” email to the author, 2 Dec. 2003.


26

commercially available for lower blends and is working on extended models, such as a

marina.75

California’s high gasoline prices make ethanol economically competitive,

suggesting that California is a feasible location to introduce it into recreational boating

applications. The study above focused upon the conventional technology where ethanol

is produced from corn. Newer technologies that convert waste biomass to ethanol, when

fully established, would provide a cheaper source of ethanol. Currently, cellulosic

ethanol is produced at similar prices to corn ethanol ($1.10 to $1.20/gal).76 Fuel ethanol

would already be cheaper if the engine was optimized for it. The federal government

currently offers a one-time income tax reduction of up to $2,000 with the purchase of a

clean-fuel vehicle (which includes fuels with at least 85% ethanol).77 Although the tax

incentive only applies to motor vehicles, one can assume that if a viable alternative to

gasoline-powered outboard engines was available, a similar tax deduction could apply.

Provided support from the government, ethanol could replace gasoline in four-stroke

outboard engines on an economic basis.

Up until this point the considerations for ethanol’s use as a fuel have been

discussed; however, in the following sections the methodology for its use in an outboard

engine can be explored.

V. History of Ethanol Use in Engines

Ethanol’s use as an alternative fuel dates back to the original Otto engine

developed in 1877, and the Ford Model T of 1908. The Model T was originally designed

75 Donlee Pumps, “Re: ethanol storage in marinas in CA,” email to the author, 2 Dec. 2003. 76 Wyman, C.E. 2003. Subject Area: Renewable and Alternative Sources. unpublished. 28. 77 Tax Incentives for Electric and Clean-Fuel Vehicles, 2003, Fueleconomy.gov, 9 Nov. 2003, <http://www.fueleconomy.gov/feg/tax_afv.shtml>.


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to run on ethanol, however as oil companies began to push the dominance of gasoline for

internal combustion, the Model T was converted to run on gas and ethanol as a fuel was

largely forgotten. It was until the 1970’s, and the oil crisis which drove gas prices to

historical highs, that ethanol reemerged as a viable alternative to gasoline. In the late

1970’s, 10% blends of ethanol and gasoline, commonly known as gasohol, became

widely available as an alternative to pure gasoline. At the same time, Brazil began a

program to introduce ethanol blends and 100% ethanol as an automotive fuel. It wasn’t

until the 1990’s, however, that the potential for vehicles primarily fueled on ethanol

began to be explored.

Brazil has set the example for the US to follow, as automobiles in Brazil have

been fueled on ethanol since the 1970’s. Currently, all cars in Brazil run on at least 22%

ethanol (with the remaining 78% being gasoline), including an estimated 40% which run

on 100% ethanol78. Brazil produces between 3 and 4 billion gallons of ethanol per year, a

large amount of which is exported to other countries, including the US. At its height in

the early 1980’s, as much as 75% of all vehicles produced ran on pure ethanol. While

that number has since plummeted to around 1% as the oil price shock subsided, the new

standard has been vehicles fueled on a 20-25% ethanol blend79.

In the United States, ethanol has been gaining popularity in the Midwest as a

viable alternative for 100% gasoline. Currently, there are 179 refueling stations in the US

that offer E85, an 85% blend of ethanol with gasoline80. The majority of these refueling

stations are based in the Midwest, as the center of US ethanol production is located in the 78 Introduction to Ethanol, Northwest Iowa Community College, 17 Oct. 2003, <http://www.nwicc.com/Module1.htm>. 79 São Paulo Sugarcane Agroindustry Union, 17 Oct. 2003, <http://www.unica.com.br/i_pages/estatisticas.asp#>. 80 Alternative Fuel Station Counts, 17 Oct. 2003, Alternative Fuel Data Center, 17 Oct. 2003, <http://www.afdc.nrel.gov/refuel/state_tot.shtml>.


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Corn Belt. US automakers have responded enthusiastically to the increased demand for

vehicles capable of running on E85; Ford and GM have both increased production of

FFV (flex-fueled vehicles), capable of running on both E85 and pure gasoline. There are

approximately 3 million vehicles on the road equipped to run on E85, and GM has plans

to expand production of FFV to more models81. Additionally, all vehicles in the US can

run on E10, commonly known as gasohol, which contains 10% ethanol82.

Each year, the number of ethanol-powered vehicles in the US has been growing,

from a mere 441 vehicles in 1993 to over 82,000 in 2002 (this value does not include the

almost 3 million FFV, which can run on ethanol, but are primarily run on gasoline). A

staggering 78% of these vehicles are in operation in the Midwest, while ethanol has yet to

infiltrate the northeast, with a 2% share83. Still, the demand for ethanol is increasing as

well; the US currently consumes over 10 million gallons of E85, up from just 48,000 in

199384.

Until recently, marine applications for ethanol have been largely ignored,

however as the popularity of ethanol fueled automobiles spreads, it has begun to spread

to boats as well. Currently, all of the major outboard engine manufacturers approve 10%

ethanol blends for use in their engines, but do not recommend using a fuel such as E8585.

There are no mass-produced outboard engines analogous to the FFV in the automobile

81 State of Wisconsin, National Ethanol Vehicle Coalition, General Motors Kick-off Multi-State E85 Public Awareness Campaign, 16 July 2003, General Motors, 17 Oct. 2003, < http://www.gm.com/company/gmability/environment/news_issues/news/e85_awareness_071603.html>. 82 What is Ethanol?, Alternative Fuels Data Center, 17 Oct. 2003, <http://afdc.nrel.gov/altfuel/eth_general.html>. 83 Estimated Number of Alternative-Fueled Vehicles in Use in the United States, Sept. 2002, Energy Information Administration, 17 Oct. 2003, <http://www.eia.doe.gov/cneaf/alternate/page/datatables/table2.html>. 84 Estimated Consumption of Vehicle Fuels in the United States , Sept. 2002, Energy Information Administration, 17 Oct. 2003, <http://www.eia.doe.gov/cneaf/alternate/page/datatables/table10.html>. 85 Ethanol Use in Two and Four Cycle Small Engines, KL Process Design Group, 17 Oct 2003, <http://www.klprocess.com/2cycleeng.htm>.


29

industry; thus there is little to no demand for marine use of E85. Several tests have been

run using ethanol blends as fuel in small engines (outboard engines), and the ethanol

blends were found to perform comparably to normal gasoline.

VI. Engine Choice Justification

Four-stroke engines were focused upon for the proposed ethanol modification for

a number of reasons. These include the ease of modification due to carburetors (as

opposed to fuel injection), oil compatibility with ethanol, and relevance to today’s

boating market.

The primary problem with two-stroke engines is that the fuel is mixed with the

lubricating oil in the ignition chamber; both are vaporized, and this leaves the oil film on

the components in the chamber. However, this oil will not mix well with ethanol. It has

been suggested that different oil, such as biodiesel, could be used in place of two-stroke

oil, and would be compatible with ethanol86. Unfortunately, there are very limited studies

on this issue and the evidence for and against are inconclusive.

When dealing with engine conversion to ethanol, the primary modification

involves the air to fuel ratio. Ethanol runs richer than gasoline due to its lesser energy

content (a 9-1 ratio compared to a 14-1 ratio); thus the amount of fuel entering the

cylinder must be increased87. This requires mechanical modifications when dealing with

a carbureted engine; however fuel injection is another story. Electronic fuel injection

requires changing the programmed ratio and sensors to determine the appropriate amount

of fuel and air; something that is quite difficult to do at the retrofitting stage. This

86 Robert Warren, Two Stroke Engines and Ethanol, 16 Sept. 2000, 20 Nov. 2003, <http://archive.nnytech.net/sgroup/BIOFUEL/428/>. 87 Keat B. Drane, Convert Your Car to Alcohol, 1980, Love Street Books, 20 Nov. 2003, <www.journeytoforever.org/biofuel_library/ethanol_drane.html>.


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modification can be very expensive and would require professionals with specialized

equipment; thus it is not feasible to retrofit a fuel-injected engine to run on ethanol at a

moderate cost88. However, the carburetor changes are relatively inexpensive, and can be

performed by a person with limited mechanical experience.

Perhaps the most important reason for using four-stroke engines for our

modification involves today’s outboard engine marketplace. We decided to focus on

smaller horsepower engines for two reasons. First, as the project was specific to

freshwater lakes, we found that the horsepower used on lakes is usually less than that on

the ocean. Second, as we are to be performing an engine modification, we had to be

conscious of our project budget. A large horsepower engine of 90hp or above could

command upwards of $10,000, and with a budget of only $1000, we decided that we

would focus on small engines out of necessity.

Small outboard engines differ from larger engines in that much of the state of the

art technology, such as direct and programmed fuel injection, is only in place for large

engines above 90-115 horsepower. Thus, lower horsepower engines use primarily older

technologies, such as electronic fuel injection or carburetors. In fact, there are virtually

no two-stroke outboard engines less than 90 horsepower which have fuel injection,

electronic or direct (see Appendix I). They instead have the high polluting carburetors,

which allow large amounts of gasoline to be unburned and released into the water and

atmosphere. Because of this, several areas in California have begun to ban all carbureted

two-strokes on their lakes89. This action has led to the gradual phasing out of small

horsepower two-strokes, and the general acceptance of four-stroke alternatives. The 88 Jay Kidwell, “ethanol boats”, The Carburetor Shop Inc., e-mail to the author, 28 Nov. 2003. 89 Tahoe Regional Planning Association, Environmental Assessment for the Prohibition of Certain two-stroke Powered Watercraft, 19 Jan. 1999, 20 Nov. 2003, < www.trpa.org/Boating/MWC%20EA.pdf>.


31

primary concerns regarding four-strokes are their increased weight, somewhat lesser

performance, and higher cost relative to two-strokes90. However, while this is a large

concern for high performing, heavy, and expensive large engines, for smaller engines

these concerns can be overcome. As the technology has improved, the weight,

performance, and cost of four-strokes has begun to approach those of two-strokes in the

lower horsepower classes91. Thus, it appears that the future of carbureted two-stroke’s

are limited. In fact, some manufacturers such as Suzuki no longer produce two-strokes

below 150 horsepower; instead they use four-strokes for their low to moderate

horsepower engines92.

For these reasons, four-strokes were chosen as the engine of choice for our study

of ethanol’s use in small horsepower outboard engines. Keep in mind, however, that the

modifications given for the four-stroke engine could be readily applied to the carbureted

two-stroke, with the only major difference the ethanol-compatible engine oil. See

Appendix J for information regarding two-stroke ethanol-compatible engine oil.

The Four-Stroke Engine

The four-stroke outboard engine has a number of aspects which must be

considered when undertaking a modification for ethanol use. The first is to note the

differences in four-stroke outboard and automotive engines. While similar, the outboard

engine lacks many of the sophisticated pollution control measures of the automotive

engine such as the catalytic converter.

90 AFA Marine Inc., four-stroke Outboard Motor vs. two-stroke Outboards, Oct. 2002, 20 Nov. 2003, <http://www.smalloutboards.com/4Stroke.htm>. 91 Mercury Marine, Technology & Water FAQ’s, 20 Nov. 2003, <http://www.mercurymarine.com/technology__water>. 92 Suzuki Marine, 2003 two-strokes, 20 Nov. 2003, < http://www.suzukimarine.com/2strokes/>.


32

Another important consideration is the method of fuel induction. As discussed

above with regards to two-strokes, smaller models tend to have carburetors, while larger

models have electronic fuel injection. This holds true for four-stroke models as well;

however, there is one important consideration. While the difference between carbureted

and direct injected two-strokes is great (carbureted models do not pass EPA 2006 and

CARB 2004 standards), all four-strokes manufactured today, regardless of fuel induction

method, surpass these standards93. Thus, while electronic fuel injected models are

somewhat cleaner and more energy efficient, the gap between the two technologies is

much less than with two-strokes. This is important, as research has shown that similar to

two-strokes, all four-strokes below 30 horsepower are carbureted. In fact, the majority of

four-strokes below 90 horsepower are carbureted; however, a few select manufacturers

have begun to offer both electronically fuel injected and carbureted models in the 30-90

horsepower range (See Appendix I). As discussed earlier, we are focusing on small

horsepower models (5-15 horsepower), and thus on carbureted four-stroke engines.

VII. Engine Modifications Necessary for Ethanol Operation

There are two main categories of the engine modifications needed to allow for

ethanol use as a fuel. These modifications are necessary for ethanol combustion and

sustainability, and to optimize the engine for ethanol use. The modifications discussed

here are general changes needed for engine components present in most four-stroke

engines.

First, we discuss the minimal modifications needed to run an engine on ethanol.

The first modification is to ensure that the fuel tank, fuel lines, and carburetor are all 93 State of California Air Resources Board, Emission Standards and Test Procedures for New 2001 and Later Model Year Spark-Ignition Marine Engines, Oct. 1999, 20 Nov. 2003, < http://www.arb.ca.gov/regact/marine/fsor.pdf>.


33

compatible with ethanol. This is primarily only a problem with older engines, as all

current engines in the US are guaranteed to run on ethanol blends. However, certain

plastic components like fuel filters should be replaced with glass alternatives.

Additionally, rubber is particularly sensitive to ethanol, and should be replaced with

Viton94. Assuming all the components are compatible with ethanol, the next step is

actual modifications to the engine. These primarily involve changes to the carburetor

used to supply the fuel-air mixture to the engine. First, the main jet, which allows fuel to

mix with the air, needs to be enlarged. Because ethanol contains a certain amount of

oxygen, this allows it to run richer than gasoline, and therefore a higher fuel to air ratio is

needed. This can be accomplished by enlarging the main jet approx. 27%95. For our

engine, we will likely purchase a carburetor rebuild kit, which will have specifications

and replacement parts for our carburetor96. Using that, we can purchase multiple jets, and

have each jet a different size (an increase of anywhere from 20-40% of the original size).

We can then undergo testing to determine which size results in the optimum performance.

This can be done by ensuring that the engine is firing correctly without ‘pinging’, and

also that the spark plugs do not become white due to excessive heat. Additionally, the

idle orifice and the accelerator pump nozzle may also need to be enlarged, depending on

the specific carburetor97.

94 Ken C. Halvorsen, “The Necessary Components of a Dedicated Ethanol Vehicle,” thesis, U. Nebraska, 1998, 19-33. 95 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>. 96 Keat B. Drane, Convert Your Car to Alcohol, 1980, Love Street Books, 20 Nov. 2003, <www.journeytoforever.org/biofuel_library/ethanol_drane.html>. 97 Mother’s Alcohol Fuel Seminar, How To Adapt Your Automobile Engine For Ethyl Alcohol Use, 1980, Mother Earth News, 20 Nov. 2003, < http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html>.


34

Another important modification involves altering the ignition timing. While

gasoline engines ignite near or at the top of the piston stroke, ethanol can have a much

earlier ignition, due to its increased vaporization time. This is accomplished by turning

the distributor housing opposite the rotor direction. While studies have shown ethanol

utilizes a 10-24 degree turn opposite the rotor direction, it is necessary to experiment with

various degrees to optimize the particular engine and prevent knocking or pinging98.

The second group of modifications is those used to optimize the engine for

ethanol; that is increasing fuel efficiency and power output. The primary modification

here involves altering the compression ratio to maximize ethanol’s efficiency. The

compression ratio of a gasoline engine is around 8.5 to one; however ethanol can tolerate

10 or 11 to one99. The two primary methods of altering the compression ratio are using

modified pistons designed for high compression ratio, or milling the cylinder head

down100. The purchase of a new piston is obviously preferred, but for the purposes of

retrofitting an outboard engine, the cost is a major deterrent. Depending on the type of

engine and the desired increase in compression ratio (quite large in the case of ethanol),

the price can range from $50 to $1000 for a high compression piston. This would suggest

the second method might be more feasible, however milling the piston can potentially

interfere with normal engine operation, and may only slightly increase the compression

98 Mother’s Alcohol Fuel Seminar, How To Adapt Your Automobile Engine For Ethyl Alcohol Use, 1980, Mother Earth News, 20 Nov. 2003, <http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html>. 99 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>. 100 Stephen P. Mullen, Compression Ratios, 2003, Night Rider.com, 20 Nov. 2003, <http://www.nightrider.com/biketech/hdhead_compression.htm>.


35

ratio (0.5 to 1 points)101. Thus, altering the compression ratio for ethanol is a luxury that

those with sufficient resources can explore; however to the average outboard boat owner,

altering the compression ratio is not necessary. For our project, it will be useful to

explore the potential to increase the compression ratio, however this is not practical until

the actual engine is obtained, due to the wide variation in piston types and costs from

manufacturer to manufacturer. This is the primary difference between retrofitting a

gasoline engine to run on ethanol and designing an ethanol engine in the production

stage; during production ethanol’s efficiency and performance can be optimized at

minimal cost by using a different piston to increase the compression ratio; however,

during the retrofitting stage altering the compression ratio is more difficult and

potentially quite costly.

IX. Modifications to the Outboard Engine

Jet Design

In order to increase the fuel to air ratio, the main jet’s diameter needed to be

enlarged. A study provided by the Mother Earth News recommended that the diameter

be increased by 20% to 40%102. Below is the Pro/ENGINEER drawing of the main jet

with the original diameter.

101 Mother’s Alcohol Fuel Seminar, How To Adapt Your Automobile Engine For Ethyl Alcohol Use, 1980, Mother Earth News, 20 Nov. 2003, <http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html>. 102 < Mother’s Alcohol Fuel Seminar, How To Adapt Your Automobile Engine For Ethyl Alcohol Use, 1980, Mother Earth News, 20 Nov. 2003, <http://www.journeytoforever.org/biofuel_library/ethanol_motherearth/me2.html>.


36

Figure 2. Original Main Jet

The original plan was to enlarge the diameters by the following increments: 20%,

25%, 30%, 35%, and 40%. Unfortunately, the manufacturer only provided three jets, so

the dimensions used were: 0.033” (20% increase – drill #66), 0.036 (30% increase – drill

# 64), and 0.039” (40% increase – drill # 61). See Appendix M for the Pro/E drawing of

the side-view of the jet and the corresponding nozzle.

Materials Ethanol Compatibility

In terms of materials compatibility, the literature research suggested compatibility

issues in using ethanol fuel in an engine designed for gasoline. In particular, ethanol can

affect rubber, plastic and metal parts. Because the ethanol would only be in contact with

the fuel system, the following compatibility issues were identified: fuel line tubing and

o-rings (rubber), the fuel filter (plastic), the fuel pump (plastic, rubber, and some metal),

and the carburetor/main jet (metal).

To solve the compatibility issue with the tubing and o-rings, the material of the

existing tubing and o-rings needed to be determined. Unfortunately, as this information

is considered proprietary, Mercury Marine was unable to offer this data. Because the


37

engine’s manual discourages the use of fuel with more than 10% ethanol, it was

determined that these parts should be replaced. To analyze the effect that ethanol would

have on the rubber, the tubing and o-rings were measured and submersed in ethanol to

determine whether corrosion or deformation would occur. After 17 days of soaking, the

resulting ethanol was slightly discolored for both the tubing and the o-rings. Upon

measurement after the soaking, it was determined that very little change to the parts

occurred in the given time period. This is consistent with current research, as it may take

a period of months to see any drastic changes. Thus, an alternative material was

investigated.

Several ethanol-friendly replacements exist as a material replacement. One study

suggested Viton (Fluoroelastomer-Terpolymer). Upon further investigation, Viton was

determined to be a suitable replacement for ethanol contact103. See Appendix N for

further information on ethanol’s compatibility with rubber. Viton GF tubing with the

same inner and outer diameter was purchased for replacement. The tubing was then cut

to proportions similar to the rubber fuel lines and put into place as depicted in blue

below.

103 Ken C. Halvorsen, “The Necessary Components of a Dedicated Ethanol Vehicle,” thesis, U. Nebraska, 1998.


38

Figure 3. Tubing in Fuel System

Three o-rings potentially come into contact with the fuel. They are located at the

intake manifold, between the fuel pump and cylinder, and on the drainage screw of the

carburetor. Butyl rubber was recommended by American Seal, Inc. as the viable

replacement material. However, because the ordered o-rings arrived with the incorrect

diameter and because one o-ring could only be specially ordered at high cost, the o-rings

were not replaced. The analysis of how ethanol affected the o-rings suggested that

drastic corrosion would not occur over short time intervals. It is also important to note

that leakage was not apparent near these o-rings, further suggesting that the seal was

maintained and that corrosion may not drastically affect these parts within the time frame

of the project.

Much like the rubber parts, the type of plastic for the fuel filter was

undeterminable. A similar strategy was implemented where the fuel filter was measured

and soaked in ethanol to determine whether corrosion or deformation would occur. In the

17 days of soaking, there was no visible change to the filter. In addition, with a minimal


39

replacement cost direct from Mercury, the filter was determined to be able to run in the

short term and could easily be replaced if corrosion was to occur.

No degradation of the fuel pump was observed while the engine ran on ethanol

through the course of this study. EDS (energy-dispersive x-ray spectroscopy) using a

Scanning Electron Microscope revealed that the fuel pump is composed primarily of

aluminum and zinc-aluminum alloys. According to the Aluminum Association,

anhydrous ethyl alcohol was corrosive to aluminum alloys, but alloy 3003 was resistant

to aqueous solutions of ethanol. Additionally, “aluminum alloys have been used

commercially for stills, heat exchangers, drums, tanks, and piping in the processing of

ethyl alcohol and products employing ethyl alcohol in their manufacture.”104

There exists the possibility that the current fuel pump is not compatible with

ethanol. The effects of ethanol on the pump should be further investigated, particularly

looking at the effects of ethanol on the body and the diaphragm. If there is evidence of

galvanic corrosion on the aluminum, a gold coating could be used to anodize the

aluminum, creating a layer of aluminum oxide. This would protect the underlying layers

of aluminum from being oxidized.105 Alternatively, ethanol-compatible fuel pumps exist

for higher horsepower engines. For example, the smallest ethanol-compatible ones

available from Summit Racing are the Holly 140 GPH (gallons per hour) fuel pump and

the Mallory 110 GPH fuel pump. These pumps would normally be used on a 550-

104Warren Hunt, “Re: ethanol and aluminum,” Aluminum Association Technical Information Service, email to the author, 23 Feb. 2004. 105 Ken C. Halvorsen, “The Necessary Components of a Dedicated Ethanol Vehicle,” thesis, U. Nebraska, 1998.


40

horsepower engine.106 Because ethanol-compatible fuel pumps exist for more powerful

engines, should a demand arise for less powerful ones, they could be readily developed.

Also, the primary material in the main jet was identified as brass. The EDS plots

for main jet and fuel pump are in Appendix O. For the carburetor, the metal was

undeterminable, as there was not material to remove for use with EDS. However,

research findings to this date did not indicate materials compatibility issues for

carburetors. Further, in taking apart the carburetor to change main jets, no evidence of

corrosion was seen where the carburetor comes in contact with fuel.

Cold Start Solutions

Perhaps the greatest obstacle to ethanol-fueled vehicles is their difficulty to start

in cold conditions. Due to the higher latent heat of vaporization and lower Reid vapor

pressure of ethanol, when the temperature drops below 11 degrees Celsius, the engine has

difficulty starting as there is not sufficient vaporization of the ethanol107. Several

solutions have been proposed to deal with this problem in automobiles; however use in

outboard engines provides a few additional challenges.

The majority of the solutions center on using an alternative fuel to ‘prep’ the

engine by heating it, then allowing the ethanol to take over. The fuel obviously needs to

have a much lower latent heat of vaporization, so that cold starting is not an issue. There

are a few other solutions proposed which consider the preheating of the ethanol fuel for

use in the engine; most of these involve the use of electricity. One aspect unique to

boating is that while automobiles in cold climates frequently can be in use in extremely

106 Lance Besse, Summit Racing, phone conversation with the author, 5 March 2004. 107 Dr. Gregory W. Davis, Development of Technologies to Improve Cold Start Performance of Ethanol Vehicles, 11 June 2001, Kettering University, 20 Nov. 2003, <http://www.michiganbioenergy.org/pubs/coldstart.pdf>.


41

cold temperatures, it is unlikely that a boat will be used for recreational purposes in

extreme cold. If the temperature drops below freezing, boaters run the risk of ice forming

on the lake, not to mention the frost and wind chill associated with cold weather boating.

Thus, while the cold start ability is important in the event of boating in sub 11 degree

temperature, this use is assumed to be infrequent, and the temperature to be relatively

moderate (above freezing). Additionally, for automobiles in extremely cold climates, the

ethanol fuel may need to be preheated throughout operation, by rerouting the exhaust or

another heat source. However, recreational boat operation is very unlikely in extreme

cold, and thus this modification is not necessary.

There are several factors which are to be considered in choosing a system for cold

starting an ethanol run engine.

• Portability – This is important in marine use, unlike automobiles, as it is not always possible to drive up to the fuel source, and the fuel may have to be transported to the boat.

• Availability – As many lakes for recreational use are located in remote locations, the fuel should be widely available.

• Fuel Cost - The fuel or method of heating should not be overly expensive, and at worst be comparable to ethanol.

• Retrofit Cost – The cost of the cold start system should be minor. • Effectiveness – The engine should start quickly • Repeatability – The cold start should work multiple times over a usage period • Environmental Impact – The cold start method should not be significantly high

polluting. This is of lesser importance, due to the aforementioned rare use of marine cold start.

• Ease of Use – As many recreational boat users have limited knowledge of outboard motor mechanics, the cold start solution should be simple to use.

The proposed solutions to the cold start problem can be broken into two

categories, various fuels and electrical heating. The fuels will be combusted for a few

seconds, heating the chamber to allow for the combustion of ethanol. The electrical

heating will heat the carburetor or fuel line to preheat the ethanol before entering the


42

combustion chamber. The different fuel options include propane, gasoline, natural gas,

hydrogen, diethyl ether from ethanol, and diethyl ether starting fluid. The electric options

include an outlet powered electric heater, and a battery powered one.

We ranked the eight potential solutions for each of the eight factors, and created a

matrix for the resulting data.

Cold Start Method Portability Availability Fuel Cost Retrofit CostEffectiveness (single start) Repeatability

Environ. Impact Ease of Use TOTAL TOTAL weighted

Gasoline 5 5 3 4 4 1 8 4 34 77Propane 6 6 4 5 4 1 7 5 38 88Natural Gas 7 7 2 6 4 1 4 6 37 94Hydrogen Gas 1 1 0 8 1 1 3 7 22 66Diethyl Ether (EtOH) 1 1 0 7 2 1 5 7 24 68Diethyl Ether (Starting Fluid) 4 4 1 1 2 1 5 1 19 39Electric Heater (outlet) 8 8 0 2 7 1 1 1 28 74Electric Heater (battery) 1 3 0 3 7 7 1 1 23 66

Table 7. Cold start solutions matrix

The column marked “Total” is a horizontal summation for each of the options.

The best solution generated by this method was the diethyl ether in starting fluid form.

However, it is unlikely that the different factors are of equal importance, therefore the

factors were weighted. The weighted summation is shown in the final column, “Total

weighted”. Fuel cost and environmental impact are not weighted, as it was felt these

were the least important factors. Due to the minor amount of fuel needed to power the

cold start system, the cost and impact were assumed to be minimal. Portability,

availability, and repeatability are weighted by a factor of two, as these were figured to be

fairly important factors. Portability and availability are important; however, not essential

to the cold start system. Repeatability is important in small amounts, however it is

unlikely that the cold start system would be used a large number of times in a short

period. Ease of use is weighted by a factor of three, as it is a very important factor.


43

Since the target market is recreational boat owners, and many do not have extensive

mechanical experience, the system needs to be simple to run. Finally, effectiveness and

retrofit cost are weighted by a factor of four. These are the most important factors in

determining our system. The system needs to be effective in starting the engine, as

ethanol alone is not sufficient in cold temperatures, and the system cost is likely to be the

primary concern of potential buyers.

Using the weighted factors, the diethyl ether starting fluid emerges as the

dominant solution. The simplicity of purchasing a can of ether starting fluid from an auto

parts store (for approx. $2) and spraying a small amount into the carburetor was apparent,

as was its strong effectiveness. In fact, later benchmark testing of the engine running on

gasoline found that at low temperatures the engine had difficulty starting on gasoline;

however, use of the ether cold starting fluid allowed the engine to start smoothly. A

detailed discussion of each of the cold start options and their ranking determination is

included in Appendix P.


44

X. Goal Engine Specifications

Area Quantification Justification Test Environmental NOx + HC emissions

1770.8 PPM 2008 CARB Exhaust Emissions Standard

Snap-on MT3505 Emissions Analyzer at Vermont Technical College

CO emissions 0.85% (reduction by 10%)

The reduction is acceptable for ethanol to be preferred over gasoline.

Same as above

Performance Horsepower 5 hp (100% of

running on gasoline – no compression ratio change)

Maximum power output of gasoline engine

Torque, RPM, horsepower relationship

Efficiency At least 0.0140 gal/hr-hp (at least 66.7% of gasoline)

Energy content ratio of gasoline to ethanol

Run known volume of fuel until engine stopped

Cold-start Must start above 30°F

Minimum starting temperature of gasoline engine

Start at cold temperature

Weight < 62.7 lbs. (110% of original engine weight)

According to Fairlee Marine

Scale

Economics Overall cost to retrofit (excluding labor)

$250 (25% of engine value maximum)

Alternative Fuel Data Center vehicle cost analysis

Economic analysis

Table 8. Engine Specifications

XI. Engine Testing

Due to seasonal constraints, the testing on the engine was adapted for running on

dry land. To do this, a test stand was constructed at the Hopkins Center Woodshop. The

shaft and propeller of the engine were submerged in water to ensure proper cooling and

run in neutral.


45

Figure 4. Engine test set-up

A series of tests were devised to acquire data for the engine running on gasoline to serve

as a benchmark from which many of the specifications were derived. These tests

acquired data for emissions from exhaust, power and fuel efficiency. These tests were

then repeated for the retrofitted engine.

Emissions

The emissions specification for our outboard engine is an important criteria, as the

primary problem with gasoline engines is air pollution. Our specification was that our

CARB 2-star engine should reach CARB 3-star levels while running on ethanol, and that

the CO levels should reduce by 10% from their gasoline-operated levels. Thus, the first

step was to test the emissions of the engine running on gasoline.

Our first possibility for emissions testing was to have our emissions tested at the

CARB emissions testing facilities at the UC-Riverside. While this would have been very

desirable, the cost and difficulty associated with sending our engine cross country to be

tested proved to be infeasible. Another option would be to collect the emissions in a

sealed container or bag, and have them sent to emissions testing consultants. This


46

method was undesirable, however, due to the cost and inaccuracy of collecting and

sending the emissions.

The option we chose to test our engine emissions was to use the Snap-On tester at

Vermont Technical College’s Automotive Engineering Department. While this tester

was designed to test automobile emissions, we adapted the exhaust system of our engine

to comply with the tester. This option was chosen due to its low cost (the authors are

extremely grateful to Vermont Tech for the complimentary use of their tester) and its

tremendous flexibility as compared to the other options.

The tests were conducted by separating the engine operation into three ranges;

idle, mid-throttle, and full throttle. For each range, emissions results were gathered four

times and the averages were taken. Those results are presented in the table below:

Throttle Exhaust T (°C) AFR CO

(%) CO2 (%)

O2 (%)

HC (ppm)

NOx (ppm)

Idle 24.7 27.81 5.52 6.12 18.94 732 71.8 Middle 24.78 32.92 0.45 10.01 18.85 141 100.25 Full 24.93 37.75 0.94 5.23 19.93 3648.5 176.50

Table 9. Gasoline Emissions Data

From the table, one can conclude that the outboard engine is very dirty compared

to an automobile engine; these levels, especially the hydrocarbon levels, far surpassed

what would be observed in even older autos.108 It is of note that the engine has the fewest

emissions in the mid-throttle, as it runs most efficiently there. However, when increased

to full throttle, the engine literally is spitting out gasoline, as reflected by the stratospheric

increase in hydrocarbons.

108 Betsy Dorries, Vermont Technical College, personal communication to author, 21 Jan. 2004.


47

For our ethanol testing, we ran the above test for our three different sized jets;

those representing 0.033”, 0.036”, and 0.039” jet diameters respectively. Unfortunately,

due to malfunctions in the testing equipment, we were forced to somewhat curtail our

procedure from the gasoline benchmark testing. We only tested the three jets at the mid-

throttle and full throttle, and only used two repetitions for the full throttle. As the idle

speed setting is independent of the modified main jet size (fuel passes through the idle

jet), an analysis to determine the optimal jet size was not applicable. A comparison of the

idle emissions for gasoline and ethanol are presented in Appendix Q. Additionally,

certain data on the equipment appeared to be inconsistent, especially the NOx readings.

However, despite the limited repetitions, distinct disparities appear between the differing

jet sizes on ethanol and the benchmark gasoline. For the combination of hydrocarbon

and NOx emissions, there is a dramatic reduction in PPM using the 0.033” jet run on

ethanol as compared to the gasoline testing. This reduction is not consistently seen in the

other jet sizes, however, suggesting that ethanol runs most cleanly using the 0.033”

diameter jet. While the ethanol NOx readings used for this comparison are given without

a great deal of confidence, the overall conclusions and relationships still hold, as the

impact of NOx levels compared to hydrocarbon levels are minimal.


48

Hydrocarbon and NOx Emissions

3825

819.5

19532481

241.25 89.5314.25 403

0500

10001500200025003000350040004500

Gas EtOH (.033) EtOH (.036) EtOH (.039)

Fuel (Jet diameter in inches)

PPM Full Throttle

Mid Throttle

Figure 5. Hydrocarbon and NOx Emissions

With regards to CO and CO2 emissions, there is a noticeable increase in CO

emissions with the introduction of ethanol. Additionally, CO2 levels correspondingly

decrease. This suggests that the engine is not running at full efficiency, in all likelihood

due to the non-optimized compression ratio of the engine for ethanol combustion.

However, despite these inefficiencies, the 0.033” diameter jet outperforms the other jet

sizes, as in the hydrocarbon and NOx emissions.


49

Figure 6. CO and CO2 Emissions

After comparing the data for the different jet sizes, it is clear that the 0.033”

diameter jet size results in optimal emissions for ethanol combustion. The emissions for

this jet size are far reduced for hydrocarbons and NOx; however, they are slightly worse

for CO and CO2. Betsy Dorries observed that the emissions were a significant

improvement over the gasoline emissions – comparable to an early-eighties

automobile.109

Power

One of the main requirements for the ethanol-fueled engine was that it exhibit

similar power as for gasoline-fueled engine. The best way to determine this would be to

use a dynamometer to obtain a horsepower versus RPM curve. An example of the curve

provided by Tohatsu can be found in Appendix R. Since a dynamometer for a five hp

109 Betsy Dorries, Vermont Technical College, personal communication to author, 3 March. 2004.

CO and CO2 Emissions

0.00%2.00%4.00%6.00%8.00%

10.00%12.00%14.00%

Gas EtOH(0.033)

EtOH(0.036)

EtOH(0.039)

Fuel (Jet diameter in inches)

Full Throttle CO%Full Throttle CO2%Mid Throttle CO%Mid Throttle CO2%


50

outboard would need to be custom-made, alternative tests were conducted to obtain the

power exhibited by the engine at mid- and full-throttle settings. The discussion of the

power testing at mid-throttle can be found in Appendix S.

To obtain the engine’s maximum power output, the relationship between torque,

horsepower, and RPM was applied:

RPMhplbfttorque 5252)( ×=− 110 Eq. 1

Five runs were performed – one on gasoline and one for each of the four jet sizes on

ethanol. The engine was started in neutral and then shifted into gear. Running the engine

at full-throttle in gear produced the largest possible load. The RPM of the engine was

measured using a digital tachometer that measured the revolutions of a piece of reflective

tape on the flywheel.

The maximum power output occurs when the engine experienced the maximum

load and maximum RPM rating. See Appendix T for a bar graph of the maximum RPM

values obtained. Assuming that the maximum power for the gasoline engine was 5.00 hp

and applying Eq. 1 to the RPM value obtained for gasoline (6230 RPM), the torque was

found to be 4.22 ft-lb. [This provides a relative relationship of power output between

gasoline and ethanol, and not highly accurate power values that could be obtained with a

dynamometer.] The torque is dependent upon the size of the propeller (diameter 8-

3/8”111). It was then assumed that the torque would remain the same for the maximum

power output of the engine running on ethanol.

525222.4 lbftRPMhp −×= Eq. 2

110 Summit, 5 March 2004, <http://www.summit.com/toolbox/techinfo/techdocs/motor-control.html>. 111 Mercury Service Manual, 4/5/6 FourStroke, 2000.


51

The preceding equation was then used to calculate the maximum horsepower for all of jet

sizes for ethanol.

Maximum Power Output

4.5

4.6

4.7

4.8

4.9

5

5.1

Gasoline EtOH - 0.028" diam. jet EtOH - 0.033" diam. jet EtOH - 0.036" diam. jet EtOH - 0.039" diam. jetFuel and Jet Size

hp

Figure 7. Maximum Power

The jet diameter to achieve the optimal power output was between 0.033” and 0.036”. It

is important to note here that the engine was designed with an engine speed limiter of

6300±200 RPM112. Additionally, the engine with the original jet was only able to run at

its maximum power for less than two minutes on ethanol. The mixture of fuel and air

was most likely too lean for the engine to continue to run. Conversely, with the 0.039”

diameter jet, the mixture was too rich, which prevented it from achieving a higher power

output.

112 Mercury Service Manual, 4/5/6 FourStroke, 2000.


52

Efficiency with Power

In converting the engine from running on gasoline to ethanol, it is important to

consider the differences in fuel properties. In particular, ethanol’s lower energy content

can result in a decrease in fuel efficiency with all other factors being equal. To make

these comparisons, efficiency data was collected for the engine running on gasoline and

on ethanol. The engine was run in neutral with a known quantity of fuel (500 mL) until

the engine stopped running. The runtime and the amount of remaining fuel were

recorded. The best way to represent the efficiency data is to include the power

component. Although the fuel consumption rate was determined with the engine running

in neutral and the power was obtained with the engine in gear, the maximum RPM values

were equivalent. The comparison of efficiency between gasoline and ethanol was

obtained for full-throttle, in neutral. For a description of the process, in which the testing

methodology was determined, and the efficiency results at mid-throttle (which did not

have dependable power results), see Appendix U.


53

Full-Throttle Efficiency with Power

0.093

0.1340.142

0.122

0.203

0

0.05

0.1

0.15

0.2

0.25


gal/h

r-hp

Figure 8. Full-Throttle Efficiency with Power

As expected, the engine running on ethanol functioned with a worse efficiency than

gasoline. With the 0.036” diameter jet, the engine had the best efficiency with ethanol.

Cold-start

Perhaps, the greatest obstacle to ethanol-fueled vehicles is their difficulty to start

in cold conditions. Due to the higher latent heat of vaporization and lower Reid vapor

pressure of ethanol, when the temperature drops below ~50 degrees Fahrenheit, the

engine has difficulty starting as there is not sufficient vaporization of the ethanol.

For the modified outboard engine, its cold-starting capabilities were first tested

using gasoline as a fuel. The logic was that the ethanol-fueled engine would only need to

start at temperatures in which the gasoline engine started, as temperatures lower than that

would not be realistic for recreational boaters. The first decision was how to control for

the temperature. One possible solution was to try and run the engine outdoors (winter in


54

New Hampshire is sufficiently cold); however, the primary drawback was that the

temperature could not be adjusted. Additionally, at the time of testing New Hampshire

was experiencing a particularly severe cold snap (high temps of ~5 degrees Fahrenheit),

and the engine would not come close to starting in the extreme cold. Therefore, an

alternate solution was to use a cold room in the Thayer School Ice Research Laboratory.

There, the temperature was controlled (below freezing), and by shutting off the

condensers in the room, the temperature was allowed to slowly rise above freezing.

The equipment used to monitor temperature was a combination of the thermostat

on the cold room, which gave a very rough approximation of the temperature, and the

Fluke IR Thermometer. This ensured that the various engine surfaces had sufficient time

in the cold room to adjust to the air temperature. While uniform temperatures between

the engine and air were unable to be obtained, the differences between the two were

minimized; thus, mimicking likely differences one would encounter during normal

operation.

The test began at an air temperature of 32 degrees Fahrenheit and an engine

temperature of 20 degrees. To start the engine, the cold-starting procedures given in the

operating manual were followed and testing began with the choke fully opened. Despite

repeated pulls, the engine refused to turn over and achieve ignition. Thus, the engine was

allowed to warm to 24 degrees, however it still refused to turn over. Finally, the air

temperature increased to 36 degrees, and the engine to 30. After a considerable amount

of effort (approximately 15 pulls of the starter cord), the engine started. This was an

encouraging result, as it showed that the engine would not operate below approximately

30 degrees, and thus our ethanol-fueled engine should only operate above that


55

temperature. Additionally, while it is reasonable to expect some boaters may operate

their engine in sub 50 degree weather, it is much more unlikely to have recreational

operation in subfreezing temperatures.

After modifying the engine to run on ethanol, an ether-assist was utilized. The

addition of a small amount of ether vapor (sold in many auto parts stores as a cold-start

for gasoline engines as well) to the carburetor air intake would allow simple ignition in

even extremely cold temperatures, and heat the cylinder enough for the ethanol to be

subsequently ignited.

For the ethanol cold-start testing, the cold rooms used for the gasoline benchmark

were inaccessible (the rooms had been experiencing malfunctions and were being

defrosted); so therefore, testing was conducted on the outdoor loading dock at Thayer.

Unlike during the gasoline testing, the temperatures were much more moderate, and the

engine was tested with the air temperature at 33 degrees Fahrenheit (very close to the

target starting temperature of above 30). The engine temperature was approximately 30

degrees. Without the cold starting aid, the engine would not turn over (this was not at all

unexpected, given the theoretical limit of ethanol ignition at 50 degrees). However, when

the ether was applied to the air intake stream, the engine started after only four pulls of

the starter cord (each was accompanied with a spray of ether). This represented a

significant increase in the ease of starting the engine on ethanol as opposed to gasoline.

As theorized, after quickly burning the ether vapor, the engine began to draw in ethanol

and ignited the fuel without problem in the preheated cylinder. Thus, the cold-start

solution satisfied and surpassed the specification of equal cold-starting ability as

compared to gasoline.


56

Due to the lack of a controlled temperature room, The exact temperature at which

the ethanol would not ignite without the ether aid was unable to be determined.

However, during the testing of emissions and efficiency, the air temperature was noted,

and consistently found that the engine required the ether at temperatures up to 50 degrees.

It is recommended that boaters using an ethanol-fueled outboard engine to first attempt to

start the engine without the use of the cold-starting aid, and then use the ether if the

engine would not turn over. At a cost of approximately $2 per spray can, this was an

extremely affordable and effective solution to the problem of cold-starting in ethanol-

fueled engines.

Weight

According to the specification, the overall weight of the engine was to increase by

no more than 10% (six pounds) after engine modification. This was to account for any

changes in the materials used in the engine, and also the cold start solution. However,

after modification of the engine to run on ethanol, the weight increase was determined to

be minimal, and well within the target specification. All materials replaced were similar

in weight, and the cold start solution added no additional weight to the engine. If

additional materials replacements for the engine were desired (such as an ethanol-

compatible fuel pump), it is unlikely that the replacement materials would drive the

engine over the target weight. This is due to the minimal weight of the ethanol-exposed

components of the engine (rubber fuel lines, O-rings, fuel pump, fuel filter, and

carburetor) as compared to the engine as a whole.


57

Jet Size Determination

To determine the ideal jet size for ethanol combustion, the three measures of

performance must be compared; emissions, efficiency, and power. Using the data

generated by the three tests, the four differing jet diameters can be ranked against each

other.

For the emissions tests, the results were consistent across the different types of

emissions (hydrocarbons + NOx and CO/CO2), and across the different throttle settings

(full and mid). The 0.033” jet diameter had the lowest emissions, followed by the 0.036,

and 0.039. The 0.028 diameter (unmodified jet diameter used for gasoline) was not

tested on ethanol, as previous testing had determined that the engine would not run

consistently on ethanol at this jet size.

With regards to full throttle efficiency, the jet sizes ranged in value from 46% -

76% of the efficiency of the gasoline run engine. Thus, only one jet size (0.036”)

satisfied the specification of >67% efficiency as compared to gasoline. However, the

0.033” jet narrowly missed out on this target value. The 0.028” jet size did surpass the

67% target, however as previously mentioned the engine repeatedly died during testing.

Finally, the power output of the four jet sizes was also compared. At full throttle,

the 0.033” and 0.036” diameter jets reached the target of five hp, while the other two

sizes did not.

Jet Diameter (in.) Emissions Efficiency Power Total 0% (0.028) 4 4 4 1220% (0.033) 1 2 1 430% (0.036) 2 1 1 440% (0.039) 3 3 3 9

Table 10. Jet Diameter Matrix


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An examination of this above matrix reveals a tie for the most optimal jet size for

ethanol combustion. Thus, it is likely that the true ideal value lies somewhere in between

the two values. However, for the purposes of this paper the 0.033” diameter was chosen

as the ideal jet size, as the emissions gains demonstrated by this jet size were more than

double the 0.036” diameter, while the efficiency loss was only 15%.

XII. Economic Analysis of Engine

After the engine was modified to run on ethanol, the overall retrofitting cost must

be determined and compared to the target overall cost described in the project

specifications. For the project purposes, the overall cost of retrofit was determined to

include the cost of ethanol compatible materials, the cost of the labor, to alter the jet

diameter sizes, and to replace the materials. For the purposes of comparison with the

target specifications, the labor cost was not included, as the modifications made were

readily done without the aid of a specialist.

Replacement of the rubber fuel lines to Viton tubing had no associated cost,

because the Viton was donated by the supplier. However, in most cases there would a

cost in acquiring the ethanol-compatible tubing. According to the supplier, the minimum

order of tubing is $25, which provides more than enough tubing necessary to replace all

fuel lines. If the fuel lines are replaced by a professional, a labor cost would also be

incurred. Thus, the overall cost of materials replacement would be $25 without labor

costs. This value can be further reduced if the Viton is purchased in bulk and used in

multiple retro-fits.

The original modification design also called for a change in the o-rings. Although

this modification was not completed, the potential cost is explained for the engine

economic analysis. The replacement o-rings of butyl rubber, type 116 and 217, need to


59

be ordered at a cost of $2.50 and $6.18, respectively. A smaller o-ring, not commonly

held in stock by suppliers, would need to be specialty ordered at a minimum of 1,180

pieces at $38 per 100 pieces. Although this constraint made this modification infeasible,

given a demand, this o-ring would merely add to the overall cost of about $0.38. Thus,

the overall cost of engine modification would be increased by $9.06.

If the modifications are done by an outside professional, a labor cost would also

be incurred. According to Fairlee Marine, the cost to replace all the fuel lines and o-rings

with already purchased materials would take approximately one hour, charged at $45 per

hour. With labor costs, the overall materials replacement would cost $79.06.

To change the jet size, no additional parts are necessary, as the optimum jet size

for ethanol can be drilled from the existing jet. For this reason, only a labor cost is

associated with this modification. Depending on the user’s level of experience, a cost

may or may not be incurred. According to the Thayer School Machine Shop, the jet size

alteration on a drill press would take one hour, charged at $60 per hour. For the project’s

purposes, the drilling was done at no charge, but would potentially increase the overall

cost by $60, to an overall cost of $139.06.

Modification Cost without

Labor Cost with Labor

Tubing $25.00 $25.00

O-ring $9.06 $9.06 Labor $0.00 $45.00

Jet Size $0.00 $0.00

Labor $0.00 $60.00

TOTAL $34.06 $139.06

Table 11. Engine modification costs with and without labor.


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XIII. Discussion of Specification Results

After completion of the ethanol engine testing, the results can be compared to the

original target specifications.

Area Target Specification Actual Specification % Deviation from Specification (if does not satisfy)

Environmental NOx + HC emissions

<1770.8 PPM 819.5 PPM

CO emissions <0.85% (reduction by 10%)

1.03% 21.2%

Performance Horsepower >5 hp (100% of

running on gasoline – no compression ratio change)

5.06 hp

Efficiency At least 0.140 gal/hr-hp (at least 66.7% of gasoline)

0.142 gal/hr-hp

1.4%

Cold-start Must start above 30°F

Started above 30°F

Weight < 62.7 lbs. (110% of original engine weight)

57 lbs.

Economics Overall cost to retrofit (excluding labor)

<$250 (25% of engine value maximum)

$34.06

Table 12. Specifications Assessment

In general, our ethanol engine satisfied the majority of the target specifications.

Exceptions were in CO emissions and efficiency; however, the efficiency result was very

close to the target specification (within 2%). One possible explanation for the CO

emissions is that the engine was not optimized to run on ethanol (through ideal air-fuel

mixture), resulting in incomplete combustion. If, however, the engine were to be

optimized, it would appear that the engine would meet the specification. This is

illustrated in Appendix Q, where a comparison between the emissions at idling speed is


61

presented. At the idle speed, the engine was optimized by altering the idle screw,

resulting in a significant decrease in CO emissions while operating on ethanol.

XIV. Marketability

Examining the results of the specifications previously discussed, several

conclusions can be drawn with respect to the overall marketability of the ethanol-fueled

outboard engine. It is clear that a small four-stroke outboard engine can be converted to

run on ethanol fuel with no loss in horsepower with reduced hydrocarbon emissions.

Additionally, the cost of retrofitting such engine is relatively minor, and it is feasible to

think that on a manufacturing level the conversion to ethanol could be done at no

additional cost to the consumer. However, the primary specification where ethanol loses

points in marketability is with regards to fuel efficiency. Ethanol requires approximately

1.5 times as much volume to achieve the same power output as gasoline. This results in

shorter operating time for a tank of fuel and higher costs due to the increased frequency

of refueling. For example, with the average gasoline and ethanol costs previously

calculated, the cost of using ethanol fuel would be approximately 46% more than using

gasoline. With an average yearly consumption of 60 gallons of gasoline (for an average

boater), an increase in yearly fuel costs from $101 to $141 could be expected. The

recreational boating community may find this to be a serious deterrent to using an

ethanol-fueled engine.

These observations were supported through contacting members of the boating

community, policymakers in California, and ethanol organizations. The majority of the

responders were encouraged by the possibility of an alternatively fueled outboard engine,


62

but expressed many of the same concerns. Randy Stratton of The Stratton Group, Inc.

commented on the marketability:

The buying public always looks towards mainstream success for their purchasing decision. If a product has had success and proven to perform at or near that of a gasoline powered engine, they will most certainly consider it. If there are benefits that outweigh the extra costs – consumers will weigh the benefits based on their own value system, their environmental awareness and the role it plays in creating additional dollar value here in the U.S.113

Chris Virgo, a mechanic at North Tahoe Marina, said that although there are a lot of

environmentally-conscious people, they are not willing to pay anything extra. Also, he

explained that boaters are currently resistant to the Lake Tahoe regulations requiring

them to give up their carburetated two-strokes.114 Jackie Lourenco at the California Air

Resources Board said that the only way that a new outboard would be marketable is if it

drastically reduced hydrocarbon and NOx emissions.115 Unfortunately, the attempts to

contact major outboard engine manufacturers were unsuccessful.

XV. Conclusions and Recommendations for Future Studies

Ethanol has been shown to be a viable alternative to gasoline for use in

recreational boat engines, due to ethanol’s better environmental performance as a fuel

over gasoline. Given the finite supply of fossil-based energy, alternatives to petroleum

are an increasingly important consideration. Ethanol is particularly advantageous in the

niche market of recreational outboard engines, and this study has proven the ability to

retrofit an engine with minimal modifications and lose little in the way of performance.

However, there is still much to be done before ethanol becomes a widespread alternative

to gasoline in outboard engines.

113 Randy Stratton, The Stratton Group, Inc., “RE: ethanol-powered outboard,” 4 March 2004. 114 Chris Virgo, North Tahoe Marina, phone conversation with the author, 5 March 2004. 115 Jackie Lourenco, California Air Resources Board, phone conversation with the author, 4 March 2004.


63

Further studies on horsepower testing using a dynamometer would aid in

supporting our data, and more specific emissions testing by government regulators such

as CARB would also help illustrate the advantages of using ethanol as a fuel.

Additionally, a future study could include larger four-stroke engines, multiple fuel

induction methods such as direct and electronic fuel injection, and even two-stroke

engines pending the determination of ethanol-compatible engine oil. This would expand

the potential market for ethanol outboard engines to include the entire boating industry,

rather than the specific niche of small, carbureted four-stroke engines.

A potential advantage of ethanol over gasoline which could be explored is the

issue of noise pollution. Many lake communities have problems with the high noise

levels due to boat traffic; however, in the testing of this study, it was observed that the

use of ethanol reduced the decibel levels produced by the engine operation as compared

to gasoline.

Future studies could also be conducted in determining the ideal air-fuel ratio for

ethanol combustion; where this study narrowed the range to 20-30% for our engine,

additional testing could pinpoint the exact ratio so as to further optimize combustion.

Furthering this optimization, advancing the ignition timing and increasing the

compression ratio at the manufacturing level could further optimize the engine, perhaps

resulting in increased power offsetting the loss in fuel efficiency for ethanol.

Finally, studies in the materials compatibility of many of the metals present in the

engine, such as aluminum, would help support the longevity of the engine. Replacing

such components as the fuel pump and fuel filter with cost-effective ethanol alternatives


64

would allow an ethanol-fueled engine to have the same reliability and durability of its

gasoline counterpart.

In conclusion, this study has demonstrated the significant benefits of using

ethanol as a boating fuel. Given the mentioned recommendations, the case for ethanol’s

viability as a fuel in recreational boating will be strengthened. Furthermore, the

successful introduction of ethanol into boating applications may lead to the use of ethanol

as a fuel in a much broader context.

XVI. Acknowledgements

The authors would like to express their gratitude to the following people: At Thayer School:

Professor Charles Wyman Professor John Collier Professor Robert Graves Doug Fraser Gary Durkee Thayer School Instrument Room Thayer School Machine Shop Paula Berg Professor Benoit Cushman-Roisin Professor Horst Richter Joan Levy Cathy Follensbee William Cote Bin Yang Daniel Iliescu Daniel Cullen

Outside sources:

Fairlee Marine Betsy Dorries and Steve Belitsos at Vermont Technical College Roberta Nichols Terry Jaffoni and Jackie Fee of Cargill Michael O'Keefe and Professor Phil Malte at University of Washington Don Mathey at Donlee Pump Company California Air Resources Board Environmental Protection Agency (especially Stout Alan) Edward Nelson at Wisconsin Department of Natural Resources


65

Tom Durbin at University of California Riverside Warren H. Hunt of the Aluminum Association Garland Lewis at Tohatsu John Cruger-Hansen Jeff Schloss at University of New Hampshire Jack Hull at Rainbow Rubber Extrusions Jay Kidwell at The Carburetor Shop, Inc. and Mile High Performance Bones Gate Fraternity Zeta Psi Fraternity

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Tax Incentives for Electric and Clean-Fuel Vehicles, 2003, Fueleconomy.gov, 9 Nov. 2003, <http://www.fueleconomy.gov/feg/tax_afv.shtml>. Tahoe Regional Planning Association, Environmental Assessment for the Prohibition of Certain 2-Stroke Powered Watercraft, 19 Jan. 1999, 20 Nov. 2003, <www.trpa.org/Boating/MWC%20EA.pdf>. Biomass Energy: Cost of Production, 2003, Oregon Department of Energy, 29 Nov. 2003, <http://www.energy.state.or.us/biomass/Cost.htm>. Outreach Projects: Alternative Fuel: Biodiesel, BoatU. S. Foundation, 16 Nov. 2003, <http://www.boatus.com/cleanwater/outreach/biodiesel.htm>. LNG (Liquefied Natural Gas) as a Fuel and Refrigerant for Diesel Powered Shrimp Boats, 2003, Centre for Alternative Fuels, 16 Nov. 2003, <http://catf.bcresearch.com/catf/catf.nsf/0/857BF7F61219213688256976006C3340?OpenDocument>. Wartsile LNG-Fuelled Engines for Offshore Vessels, Marine and Industrial Report, 29 Nov, 2003, <http://www.marinereport.com.sg/dec2001/wartsila.php>. About Natural Gas, NGV, 19 Nov. 2003, <http://www.ngvc.org/ngv/ngvc.nsf/bytitle/fastfacts.htm>. M. L. Poulton, Alternative Fuels for Road Vehicles (Boston: Computational Mechanics Publications, 1994). Clean Alternative Fuels: Compressed Natural Gas, 2002, EPA, 1 Dec. 2003, <http://www.epa.gov/otaq/consumer/fuels/altfuels/compressed.pdf>. Electric Drive Systems, Beckman Boatshop Limited, 29 Nov. 2003, <http://www.steamboating.net/electric.html>. Fuel Cells, 2003, 29 Nov. 2003, <http://www.boatsyachtsmarinas.com/bestsellers/html/fuel_cells.html>. First Hydrogen Fuel Cell Water Taxi on San Francisco Bay Powered by Anuvu, 2003, Yahoo! Finance, 29 Nov. 2003, <http://biz.yahoo.com/prnews/031016/sfth089_1.html>. Weekly Average Propane Prices, 2003, New York State Energy Research and Development Authority, 1 Dec. 2003, <http://www.nyserda.org/nyepf.html>. 2003 Unleaded Gasoline Statewide Averages, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/retail_gasoline_prices.html#2003>.


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Graph of Ethanol Fuel History – 18 Months, 2003, OXY-FUEL News Price Report, 17 Nov. 2003, <http://www.energy.ca.gov/gasoline/graphs/ethanol_18-month.html>. Graph of Ethanol Fuel History – Last Ten Years, 2003, OXY-FUEL News Price Report, 17 Nov. 2003, <http://www.energy.ca.gov/gasoline/graphs/ethanol_10-year.html>. Vehicle Buyer’s Guide for Consumers, US Department of Energy – Energy Efficiency and Renewable Energy, 2 Dec. 2003, <http://www.ccities.doe.gov/vbg/consumers/how_much.shtml>. The Cost of Ethanol, C&T Brasil, 30 Nov. 2003, <http://www.mct.gov.br/clima/ingles/comunic_old/alcohol4.htm>. Warren Hunt, “Re: ethanol and aluminum,” Aluminum Association Technical Information Service, email to the author, 23 Feb. 2004. Lance Besse, Summit Racing, phone conversation with the author, 5 March 2004. Betsy Dorries, Vermont Technical College, personal communication to author, 21 Jan. 2004, 3 Mar. 2004. Summit, 5 March 2004, <http://www.summit.com/toolbox/techinfo/techdocs/motor-control.html>. Mercury Service Manual, 4/5/6 FourStroke, 2000. Randy Stratton, The Stratton Group, Inc., “RE: ethanol-powered outboard,” 4 March 2004. Chris Virgo, North Tahoe Marina, phone conversation with the author, 5 March 2004. Jackie Lourenco, California Air Resources Board, phone conversation with the author, 4 March 2004. William Mustain, Andrew Adamczyk. Determination of Plausible Fuel/Oil Mixtures for Two-Stroke Ethanol-Fueled Engines. 3 Apr. 2001. 20 Nov. 2003, <http://www.iit.edu/~ipro317/s01/Documents/Oil.pdf>. DuPont Dow Elastomers Chemical Resistance Guide, 2004. Garland Lewis, Tohatsu, “FW: Tohatsu,” email to author, 27 Feb 2004. Michael Moran and Howard Shapiro, Fundamentals of Engineering 4th Ed. (New York: Wiley, 2000).


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Appendix A. Comparison of Ethanol Fuel Properties to Gasoline116

Property Unleaded Gasoline Property Unleaded Gasoline Ethanol Description Volatile dark liquid with

a strong aroma Colorless liquid with alcohol

aroma Formula C4-C12 CH3CH2OH Molecular Weight 110 avg., 100-105 avg. 46.07 C, wt % 85 to 88 52.14 H, wt % 12 to 15 13.13 O, wt % Negligible 34.47 Density 690 to 800 g/L@20°C 789.3 g/L@20°C Freezing Point -40°C -114°C Atmospheric Boiling Point Latent Heat of Vaporization (per mass basis)

27 to 225°C 0.349 MJ/kg, (20°C)

78.5°C 0.839 MJ/kg (20°C)

Latent Heat of Vaporization (per volume basis)

0.251 MJ/L (20°C) 0.662 MJ/L (20°C)

Latent Heat (per mass of air for a stoichiometric mixture @ 15.6°C)

23.2 kJ/kg air 102.24 kJ/kg air

Flash Point -43 to -39°C 12.8°C Auto-ignition Point 257°C 423°C Flammability Limits, (Vol. % in Air)

1.4 to 7.6 4.3 to 19 % in air

Higher Heating Value (per mass basis)

47.2 MJ/kg @ 20°C avg. 29.8 MJ/kg@20°C

Higher Heating Value (per volume basis)

34.81 MJ/L 23.56 MJ/L

Lower Heating Value (per mass basis)

~43 MJ/kg avg. 27 MJ/kg

Lower Heating Value (per volume basis)

32.16 MJ/L @ 20°C avg. 21.09 MJ/L @ 20°C avg.

Viscosity 3.4 centipoise @ 20°C 1.19 centipoise @ 20°C Specific Gravity 0.750 @ 15.6°C 0.794 @ 15.6°C Stoichiometric AF Mass Ratio 14.7 8.97 Stoichiometric AF Volumetric Ratio

55 14.32

Water Solubility, wt% @ 20°C 0.009 Infinite Octane Number (R=research, M= motor)

88-98 (R), 90 to 100 (R), 82-92 (M), 81-90 (M)

111 (R), 108 (R), 96-113 ((R+M)/2), 92 (M)

Heat of Vap./LHV 0.0081 0.0343 Cetane Number <5 13 to 17 Reid Vapor Pressure 48-103 kPa @ 38°C 16 kPa @ 38°C Flame Luminosity (Relative to Gasoline)

100% 3%

Power Increase over Gasoline 0% 5%

Table 13. Comparison of Ethanol Fuel Properties to Gasoline

116 Michael O’Keefe, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake,” Thesis, University of Washington, 2000.


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Appendix B. Project Timetable

WEEK 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 TASKS ENGS 190 ENGG 290 Environmental Background research Investigate EtOH properties Investigate effects of gas/EtOH in lakes Investigate regulations Economic Case Study Background research Determine most applicable location Investigate infrastructure for fuel EtOH Investigate infrastructure cost Determine retail cost of EtOH on lakes Technical Background research Determine engine type Investigate engine modification for EtOH Investigate cold start technologies Evaluate literature research Search for and secure engine Written proposal Oral proposal Written progress report Oral progress report Pre-testing procedure and preparation Design retrofit for engine Benchmark testing for gasoline Materials acquisition for retrofit Construct prototype for ethanol Test ethanol prototype for performance Test ethanol prototype for emissions Cost analysis of retrofitted engine Investigate marketability of engine Implementation report via website Oral Progress Report Written Final Report Oral Final Report Legend Work Completed


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Appendix C. Alternative Fuels for Gasoline Marine Engines

In order to reduce pollutants from boats, there are only three viable alternatives:

man-powered, wind-powered, and finding a new fuel or power source. A fourth option

would be to completely redesign the engines for better gasoline or diesel efficiency, but

that would need to be done at the manufacturers’ level. The best option would be to

investigate alternative fuels and power sources. A variety of alternative ways for

powering motorboats have been applied – biodiesel, liquefied or compressed natural gas

(LNG or CNG), electricity, and fuel cells. Propane or alcohol fuels have not been used in

boating propulsion applications, but will be considered here.

Alternative Fuel Appl

icab

ility

Avai

labi

lity

Cos

t

Ener

gy O

utpu

t R

elat

ive

to

Gas

olin

e

Envi

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enta

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Ease

of E

ngin

e M

odifi

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Cos

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e M

odifi

catio

n

Tota

l

Biodiesel 7 4 7 7 5 7 7 44Liquefied/compressed natural gas 7 3 2 6 6 3 4 31Electricity 1 1 1 1 1 7 7 19Hydrogen fuel cell 7 7 3 1 1 7 7 33Propane 1 2 6 5 7 4 3 28Methanol 1 4 4 4 4 1 1 19Ethanol 1 4 4 3 3 1 1 17

Table 14. Alternative Fuels for Gasoline Marine Engines Matrix

Biodiesel is an alternative for using diesel in marine engines. Biodiesel was used

to fuel Bryan Peterson’s marine journey around the world in 1992-1994 and is being

considered for tour boats on Crater Lake in Oregon.117 The optimal blend is 20%

bodiesel/80% petroleum diesel (by volume). This particular blend will reduce emissions,



C2

improve lubricity, help clean injectors, fuel lines, pumps and tanks, and improve diesel

engine performance without requiring any modifications to the existing engines. Fuel

filters will need to be replaced more often, as the will clog more with the biodiesel fuel.

Also, the biodiesel blend has a higher cost per gallon - $1.10 per gallon with petroleum

diesel at $0.90 per gallon and soybean biodiesel at $1.80 per gallon.118 A greater than

20% blend would require some modifications as the biodiesel’s solvent properties would

react with certain types of rubber gaskets and hoses. In addition, biodiesel is safer to

store and transport than petroleum diesel as it has a higher flash point and is classified as

only combustible and not flammable or explosive.119 But, biodiesel can only be used in

engines designed to run on diesel and not gasoline.

Liquefied and compressed natural gas provide two more options for an alternative

to diesel as marine fuel. Diesel-powered shrimp boats have been adapted to run on dual

fuel – LNG and diesel with LNG providing 80% of the total heat addition at full load for

both engines.120 Wartsila Corporation produces LNG-fueled engines for offshore vessels,

which would lower NOx and CO2 emissions and have greater fuel efficiency.121 The fuel

tanks would have increased weight, volume and cost over conventional fuel tanks. These

fuels are typically applied towards large-scale marine applications, as the main

118 Biomass Energy: Cost of Production, 2003, Oregon Department of Energy, 29 Nov. 2003, <http://www.energy.state.or.us/biomass/Cost.htm>. 119 Outreach Projects: Alternative Fuel: Biodiesel, BoatU. S. Foundation, 16 Nov. 2003, <http://www.boatus.com/cleanwater/outreach/biodiesel.htm>. 120 LNG (Liquefied Natural Gas) as a Fuel and Refrigerant for Diesel Powered Shrimp Boats, 2003, Centre for Alternative Fuels, 16 Nov. 2003, <http://catf.bcresearch.com/catf/catf.nsf/0/857BF7F61219213688256976006C3340?OpenDocument>. 121 Wartsile LNG-Fuelled Engines for Offshore Vessels, Marine and Industrial Report, 29 Nov, 2003, <http://www.marinereport.com.sg/dec2001/wartsila.php>.


C3

advantages are seen in dedicated heavy-duty engines.122 Natural gas typically will cost

15% to 40% less than gasoline.123

Electric marine engines are designed to replace internal combustion engines.

They are typically only used on a small scale, although they can be used to produce high

speeds. Cruising range using electric drives are solely a function of the available battery

power and the discharge rate or boat speed. In practice it is often more feasible to

compromise speed for range and battery capacity for space. Electric drive systems are

particularly practical in boats that are easily pushed through the water – boats with

narrow beams, light displacement, and good hull design. Electric power for boat

propulsion is more efficient.124 But, they are not widely in use and the batteries are not

easily and quickly rechargeable125.

Fuel cells could provide pollutant-free marine transportation. Anuvu produced

the first hydrogen fuel cell-powered water taxi to be run on the San Francisco Bay in

October 2003. It only emits water vapor and heat.126 These fuel cells are best applicable

for government ferries and commercial marine fleets. They could be adapted for

recreational boating, but hydrogen fuel sources (needed to recharge the fuel cell) are not

readily available, other than in the form of fossil fuels.127 Also, hydrogen fuel cells are

still a very new technology.

122 M. L. Poulton, Alternative Fuels for Road Vehicles (Boston: Computational Mechanics Publications, 1994). 123 Clean Alternative Fuels: Compressed Natural Gas, 2002, EPA, 1 Dec. 2003, <http://www.epa.gov/otaq/consumer/fuels/altfuels/compressed.pdf>. 124 Electric Drive Systems, Beckman Boatshop Limited, 29 Nov. 2003, <http://www.steamboating.net/electric.html>. 125 Fuel Cells, 2003, 29 Nov. 2003, <http://www.boatsyachtsmarinas.com/bestsellers/html/fuel_cells.html>. 126 First Hydrogen Fuel Cell Water Taxi on San Francisco Bay Powered by Anuvu, 2003, Yahoo! Finance, 29 Nov. 2003, <http://biz.yahoo.com/prnews/031016/sfth089_1.html>. 127 Fuel Cells, 2003, 29 Nov. 2003, <http://www.boatsyachtsmarinas.com/bestsellers/html/fuel_cells.html>.


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Propane has not been applied to marine propulsion applications to date. It has a

high octane rating of 112 RON, where a higher compression ratio would result in

improved thermal efficiency. Because propane has a simple chemical composition, more

complete combustion occurs, resulting in lower CO and HC emissions than gasoline.

Propane engines, once fully running (because the propane is already in gaseous form), do

not experience cold-start issues. In terms of durability, propane provides an advantage

over gasoline – engine life could be 50% longer as a result of reduced cylinder wear

during cold starting. There is a penalty of power output from using propane. In order to

compensate for this, the engines size would need to be increased. Gasoline engines can

be converted to run on propane but it would be difficult to optimize. In addition the fuel

tank would need to be enlarged to achieve the equivalent vehicle operating range.128 The

retail price of propane (as of 24 November 2003) was $1.498 per gallon.129

Methanol would provide environmental benefits over gasoline, but modified

engines would not be able to run efficiently on 100% methanol. New technology would

need to be developed and manufactured to obtain maximum performance. Methanol is

similar to ethanol but it has a lower energy content value – 16 MJ/L versus 21.2 MJ/L.

Its wholesale price is between $0.30 and $0.60 per gallon. In addition, increasing the

efficiency of a methanol-burning engine could result in greater NOx emissions. 130

For a detailed discussion of ethanol, refer to the body of the paper.

128 M. L. Poulton, Alternative Fuels for Road Vehicles (Boston: Computational Mechanics Publications, 1994). 129 Weekly Average Propane Prices, 2003, New York State Energy Research and Development Authority, 1 Dec. 2003, <http://www.nyserda.org/nyepf.html>. 130 Michael O’Keefe, “Biofuels and Internal Combustion Engine Options for Tour Boats on Crater Lake,” Thesis, University of Washington, 2000.


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Appendix D. Summary of Material Safety Data Sheets for Gasoline and Ethanol Sources: MFA Oil Material Safety Data Sheets, Unleaded Gasoline. <www.mfaoil.com/MSDS/MSDS%20Index.htm> PC Chem Material Safety Data Sheet, Ethanol <www.chemsupply.com.au/MSDS/1CH9O.pdf> NFPA Safety Ratings

Gasoline Ethanol Health 3 1 Fire 3 3 Reactivity 0 0 Rating descriptions: 1 = slight, 2 = moderate, 3 = high, 4 = extreme Exposure Limits Gasoline Ethanol OSHA 300 ppm 1000 ppm 1 ppm (benzene) Health Effects Gasoline Acute Exposure: Eye: Liquid may cause irritation with erythema and pain. Prolonged or

extensive contact may cause blistering and, in extreme cases epidermal necrolysis. A 12 year old boy partially immersed in a pool of gasoline for 1 hour experienced hypotension, abdominal tenderness, disseminated intravascular coagulation, transient hematuria, nonoliguric renal failure and an elevated serum amylase. Autopsy revealed cerebral edema, diffuse bilateral pneumonia, biventricular cardiac enlargement, toxic nephrosis, fatty infiltration of liver and peripancreatic fat necrosis.

Skin: Repeated or prolonged contact with the liquid may cause irritation,

dermatitis and defatting of the skin with drying and cracking or burns and blistering. Some individuals may develop hypersensitivity, probably due to additives.

Inhalation: At 160-270 ppm throat irritation may occur within several hours. At 2000

ppm mild anesthesia may occur within 30 minutes. Other symptoms of central nervous system depression may include headache, nausea,


D2

vomiting, dizziness, drowsiness, facial flushing, blurred vision, slurred speech, difficulty swallowing, staggering, confusion and euphoria. At higher levels dyspnea, pulmonary edema and bronchopneumonia may develop. Further depression may occur with weak respiration and pulse, nervousness, twitching, irritability, and ataxia. Severe intoxication may result in delirium, unconsciousness, coma, and convulsions with epileptiform seizures. The pupils may be constricted or, in comatose states, fixed and dilated or unequal; nystagmus may also occur. May also affect the liver, kidneys, spleen, brain, myocardium and pancreas. Death may be due to respiratory or circulatory failure or ventricular fibrillation. Extremely high concentration may cause asphyxiation.

Ingestion: May cause irritation and burning of the gastrointestinal tract with nausea,

vomiting and diarrhea. Absorption may cause initial central nervous stimulation followed by depression. Symptoms may include a mild excitation, restlessness, nervousness, irritability, twitching, weakness, blurred vision, headache, dizziness, drowsiness, incoordination, confusion, delirium, unconsciousness, convulsions and coma. Cardiac arrythmias may occur. Transient liver damage is possible. Direct or indirect aspiration may cause chemical pneumonitis with pulmonary edema and hemorrhage, possibly complicated by bacterial pneumonia, and less frequently, by emphysema and pneumonthorax. Signs of pulmonary involvement may include coughing, dyspnea, substernal pain,

Chronic Exposure: Eye: Repeated or prolonged exposure may cause conjunctivitis and possible

gradual, irreversible loss of corneal and conjunctival sensitivity. Skin: Repeated or prolonged contact with the liquid may cause irritation,

dermatitis and defatting of the skin with drying and cracking or burns and blistering. Some individuals may develop hypersensitivity, probably due to additives.

Inhalation: With few exceptions, most of the reported effects of repeated inhalation

are from intentional "sniffing" of gasoline rather than workplace exposure. Reported symptoms include headache, nausea, fatigue, anorexia and weight loss, pallor, dizziness, insomnia, memory loss, nervousness, confusion, muscular weakness and cramps, peripheral neuropathy, polyneuritis, and neurasthenia. It is unclear whether some of these symptoms may have been due to gasoline containing lead. Liver and kidney damage are also possible. In a 90 day study, male but not female rats exhibited a severe, dose-related renal toxicity. In another study, an increase in renal adenomas and carcinomas in male rats and an increase in hepatocellular adenomas and carcinomas in female mice were reported.


D3

Ingestion: No Data Available Ethanol Acute Exposure: Eye: Liquids may cause stinging and redness, no long term adverse effects.

Vapors may also cause irritation to eyes Skin: May cause mild irritation, Prolonged or repeated contact may cause

defatting of the skin resulting in dermatitis Inhalation: May cause mucous membrane irritation, central nervous system

depression, headache, nausea, and tiredness. Delirium and unconsciousness at high exposure.

Ingestion: May cause vomiting; shallow, rapid pulse; delirium, unconsciousness;

possibly death at VERY high levels. If swallowed, may be aspired resulting in inflammation and possible fluid accumulation in lung.

Chronic Exposure: Liver effects have been observed in oral subchronic and chronic exposures to large amounts of ethanol. Reproductive effects, fetotoxicity, and fetal death observed in some animals.


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Appendix E. Emission Regulations Plots

Figure 9. EPA 2006 Emissions Limits131

Figure 10. CARB 2008 Emissions Limits for Marine Outboards and Personal78



F1

Appendix F. Production of Ethanol132

Ethanol can be manufactured by the fermentation of sugars derived from sugar,

starch, or cellulosic material or by the reaction of ethylene with water. The former is

preferred to produce fuel ethanol, as ethylene is quite expensive.

Ethanol Production from Sugar Crops

Brazil is the world-leader in ethanol production and uses this method. Brazilian

sugar is mostly from sugarcane. Sugar is fermented to ethanol by adding common yeasts,

by the following reaction:

C6H12O6 2C2H5OH + 2CO2

51.1 kg of ethanol can be obtained stoichiometrically for every 100 kg of sugar

fermented, with yeast performed up to 92% of this. The energy balance ratio of ethanol

energy output to fossil fuel input is between 5.9 and 8.2.

Ethanol Production from Starch Crops

The majority of fuel ethanol consumed in the US is made from starch by either

dry or wet milling operations – with the majority of the starch coming from corn. For the

dry milling operation, saccharification occurs by the following hydrolysis reaction:

(C6H10O5)n + nH2O nC6H12O6

Then yeast is added to the sugar and fermented, as discussed above. The resultant “beer”

ethanol is then distilled in a product recovery operation until about 95% purity is reached

– near the azeotropic composition. The mixture is then dehydrated to produce anhydrous

ethanol. Overall, 365 to 390 kg of ethanol can be produced by a metric ton of corn

processed. The wet milling process involves processing the corn in steeping and physical

132 Wyman, C.E. 2003. Subject Area: Renewable and Alternative Sources. unpublished.


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milling operations to separate the starch, protein, fiber, and germ. Overall, one metric

tonne of corn can yield 370 kg of ethanol. It is important to note the protein from the

corn and the yeast is sold for animal feed – the major market for which corn is grown.

One volume of ethanol will generate 34% more energy than is need to manufacture it

(overall weighted average of production facilities).

Ethanol Production from Cellulosic Biomass

Ethanol can be produced from sugars contained within the structural portion of

plants. Cellulosic biomass is found in the agricultural residues, forestry residues, and

portions of municipal solid waste. Cellulosic biomass can be grown with low energy

inputs, and can be obtained for minimal cost. Conceptually, the overall process for

converting cellulosic biomass into ethanol is similar to that which processes corn. Acids

and enzymes can be used to convert the cellulose into fermentable sugars. The

simultaneous saccharification and fermentation (SSF) approach is used to convert the

glucose into ethanol as soon as it is formed. Molecular sieves are applied to remove the

remove the water from the azeotropic mixture to obtain anhydrous ethanol. Current

technology results in a net energy output from 16.7 to 21.2 MJ/L of ethanol.


F3

Figure 11. Schematic for Ethanol Production


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Appendix G. Historical Cost of Ethanol

Figure 12. US Average Ethanol and Corn Prices133

133 Mark Yancy, The Investment Climate for Ethanol Production in California, 2003, BBI, 29 Nov. 2003, <http://www.bbiethanol.com/doe/ca/Yancey-CA-DOE.pdf>.


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Figure 13. Fuel Ethanol Terminal Market Price (18 Month History)134

134 Graph of Ethanol Fuel History – 18 Months, 2003, OXY-FUEL News Price Report, 17 Nov. 2003, <http://www.energy.ca.gov/gasoline/graphs/ethanol_18-month.html>.


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Figure 14. Fuel Ethanol Terminal Market Price (10 Year History)135

135 Graph of Ethanol Fuel History – Last Ten Years, 2003, OXY-FUEL News Price Report, 17 Nov. 2003, <http://www.energy.ca.gov/gasoline/graphs/ethanol_10-year.html>.


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Appendix H. Ethanol Fuel Calculations Gasoline Equivalent Price Range (Table: Price Range for California Ethanol)

( ))(

223.1$)()(87.0

)(406.1$

gasolinegalgasolinegalEtOHgal

EtOHgal=×

( ))(

366.2$)()(51.1

)(567.1$

gasolinegalgasolinegalEtOHgal

EtOHgal=×

Energy Content Ethanol to Gasoline Ratio

)()(51.1

100,76

000,115

gasolinegalEtOHgal

galBtu

galBtu

=

Optimized Engine Ethanol to Gasoline Ratio

)()(87.0

115100

gasolinegalEtOHgal=

Energy Content Conversion from Gasoline to Ethanol

)(1020.6)()(51.1)(108,770 6 EtOHgal

gasolinegalEtOHgalgasolinegal ×=×

Optimized Engine Conversion from Gasoline to Ethanol

)(1057.3)()(87.0)(108,770 6 EtOHgal

gasolinegalEtOHgalgasolinegal ×=×


H2

Statewide average for regular gasoline – adjusted for lakeshore consumption from 6/16/03 to 9/15/03136

Date Regular 9/15/2003 2.034 9/8/2003 2.085 9/1/2003 2.1 8/25/2003 2.101 8/18/2003 1.92 8/12/2003 1.743 8/4/2003 1.703 7/28/2003 1.707 7/21/2003 1.725 7/14/2003 1.757 7/7/2003 1.785 6/30/2003 1.8 6/23/2003 1.805 6/16/2003 1.787

Average = 1.861

991.135.022.0861.1 =+− Note: This is a very conservative estimate as we have heard a few quotes about the cost of gasoline in California marinas during the summer of 2003 to be between $2 and $2.50. Not enough responses were received from marinas (as they are now closed) to do a statistical analysis of gasoline selling prices on lakes.

136 2003 Unleaded Gasoline Statewide Averages, 2003, California Energy Commission, 29 Nov. 2003, <http://www.energy.ca.gov/gasoline/retail_gasoline_prices.html#2003>.


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Appendix I. Fuel induction method for engines by major manufacturers Honda – offers four-stroke engines 2hp – 90hp Carburetors 115hp – 225hp Programmed Fuel Injection Mercury – offers 2 and four-stroke engines two-stroke 2.5hp – 200hp Carburetors 150hp – 250hp Electronic Fuel Injection 75hp – 250hp Direct Fuel Injection four-stroke 4hp – 90hp Carburetors 30hp – 115hp Electronic Fuel Injection Yamaha – offers 2 and four-stroke engines two-stroke 8hp – 150hp Carburetors 150hp – 250hp Electronic Fuel Injection 150hp – 300hp Direct Fuel Injection four-stroke 2.5hp – 90hp Carburetors 115hp – 225hp Electronic Fuel Injection Evinrude – offers two-stroke engines 115hp – 250hp Direct Fuel Injection Johnson – offers 2 and four-stroke engines two-stroke 3.5hp – 175hp Carburetors four-stroke 4hp – 15hp Carburetors 40hp – 140hp Electronic Fuel Injection Suzuki – offers 2 and four-stroke engines two-stroke 150hp – 225hp Electronic Fuel Injection four-stroke 4hp – 30hp Carburetors 40hp – 250hp Electronic Fuel Injection


J1

Appendix J. Ethanol-compatible oil for two-stroke There has been very little research conducted on using ethanol in two stroke

engines. The primary reasons for this center on the largely outdated nature of the two

stroke engine (automobiles and many other vehicles only utilize four stroke), and the

incompatibility of ethanol with two stroke engine oil. Some suggestions have been

frequently posted on an online biofuels message board, which discuss the incompatibility

of using ethanol and two-stroke engine oil. One frequent suggestion was the use of

biodiesel as an oil, as it mixes well and has good lubricating properties137. Another was

the use of synthetic motor oils, such as Mobil One. However, we have failed to find any

studies substantiating these suggestions.

The only study we found discussing two stroke engine oils done by the Illinois

Institute of Technology138. They found two synthetic oils (Castrol TTS and Triton X-

100) which mixed well with ethanol, and provided good lubrication to the engine.

137 Robert Warren, Two Stroke Engines and Ethanol, 16 Sept. 2000, 20 Nov. 2003, <http://archive.nnytech.net/sgroup/BIOFUEL/428/>. 138 William Mustain, Andrew Adamczyk. Determination of Plausible Fuel/Oil Mixtures for Two-Stroke Ethanol-Fueled Engines. 3 Apr. 2001. 20 Nov. 2003, <http://www.iit.edu/~ipro317/s01/Documents/Oil.pdf>.


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Appendix K. Efforts in Obtaining an Engine

During the first term, of study we undertook an extensive search to obtain an

outboard engine for our project. We quickly realized that obtaining a donated engine was

not feasible, as retailers and distributors were unwilling to donate an engine, and engine

manufacturers were unhelpful and unreachable to our requests. Additionally, we

contacted every Honda and Mercury distributor in a 100-mile radius, looking for a used

or new four-stroke outboard engine for under $1000. Unfortunately, we were

unsuccessful. We attribute this to the relatively small used four-stroke market (due to

their recent widespread popularity), and the higher price of four-stroke engines compared

to two-stroke models. Additionally, we were only comfortable spending up to $750, as

we budgeted $250 for any modifications necessary to run on ethanol (a worst case guess).

In response to this failed search, we petitioned Professor Graves for an increase in funds

to $1500, and this request was granted.

We identified and purchased a Mercury 5 horsepower four-stroke outboard engine

from Vermont Home and Marine in Williston, Vermont for $1000. This cost included

the auxiliary fuel tank and fuel line.


L1

Appendix L. 2000 Mercury 5 hp four-stroke outboard HP @ Prop: 5 kW @ Prop: 3.7 Max RPM (WOT): 4500-5500 Cylinder/Configuration: 1 Displacement (CID/cc): 7.5/123 Bore & Stroke (in): 2.32 x 1.77 Bore & Stroke (mm): 59 x 45 Cooling System: Water cooled w/thermostat Ignition System: CDI Starting: Manual Gear Ratio: 2.15:1 Gear Shift: F-N-R Steering: Tiller Alternator Amp: Optional 4-amp lighting/2-amp charging Alternator Watt: Optional 50-watt lighting/25-watt charging Trim Positions: 6 Shallow Water Drive: Standard Exhaust System: Through prop Lubrication System: Wet sump Fuel Induction System: 2-valve pushrod Remote Fuel Tank: Standard Remote Fuel Tank (US Gal): 3.2 Remote Fuel Tank (L): 12 Shaft Length (inches): 15/20 Shaft Length (mm): 381/508 Dry Weight (lbs.) (Lightest Version model, excludes engine oil, rigging, hardware and propeller): 55 Dry Weight (kg.) (Lightest Version model, excludes engine oil, rigging, hardware and propeller): 25 Operator Warning System: Low oil pressure Overrev Protection: Standard Available Propellers: Consult Current Dealer Propeller Guide CARB Star Rating: 2 Oil: Mobil One Synthetic Gasoline Fuel: Shell 87 Octane Unleaded Ethanol Fuel: Fuel Ethanol with Natural Gasoline Denaturant (2-5%) Starting Fluid: Pyroil Extra Strength Starting Fluid From www.mercurymarine.com


L2

Figure 15. Fuel System Schematic

Ref#

Description

1 INLET MANIFOLD 2 O RING 3 BOLT (M6 X 25 MM) 4 INSULATOR GASKET 5 GASKET 6 TUBING 7 CLIP 8 FUEL PUMP 9 O RING 10 SCREW (M6 X 25 MM) 11 CHOKE ROD 12 BUSHING 13 BOLT (M6 X 14 MM) 14 WASHER 15 CLAMP 16 CHOKE LINK WIRE 17 BOLT (M6 X 16 MM 18 BRACKET 19 COLLAR 20 COLLAR 21 NUT 22 AIR SILENCER 23 FLAME TRAP 24 BOLT (M6 X 85 MM) 25 WASHER 26 CLAMP 27 TUBING 28 FUEL FILTER 29 TUBING 30 FUEL CONNECTOR 31 BOLT 32 WASHER 33 PROTECTIVE CAP


L3

Figure 16. Carburetor Schematic

Ref#

Description

1 CARBURETOR 2 •» STOP SCREW 3 •» SPRING 4 •» PILOT JET 5 •» PILOT SCREW SET 6 •» MAIN NOZZLE 7 •» MAIN JET 8 •» FLOAT VALVE 9 •» CLIP 10 •» FLOAT PIN 11 •» FLOAT 12 •» GASKET 13 •» FLOAT BOWL 14 •» SCREW (M4 x 12) 15 •» DRAIN SCREW (M5 x 6) 16 •» O RING 17 PLUG

Schematics and part lists from www.mercurypartsexpress.com


M1

Appendix M. Additional Pro/E Drawings

Figure 17. Main Jet Side View

Figure 18. Main Nozzle Front View

Figure 19. Main Nozzle Side View


N1

Appendix N. Rubber and Ethanol Compatibility

Figure 20. Rubber Replacement Ethanol Compatibility Table


O1

Appendix O. EDS Results

Figure 21. EDS for Main Jet of Carburetor

Figure 22. EDS for Fuel Pump


P1

Appendix P. Cold-start Options

The first option is propane. Propane is available in over 10,000 locations

nationwide139, ensuring for reliable availability. Propane tanks are fairly portable, as any

gas grill owner can attest, and can be readily transported. Propane fuel cost $2.09 per

Gasoline Gallon Equivalent as of Feb. 10, 2003, which makes it one of the most

expensive alternative fuels140. The cost of retrofitting a car to run on propane is estimated

to be between $2000 and $2500, but for the cold starting purposes the cost would be

much less141. It is, however, more expensive than a gasoline cold start system due to the

propane torch kit which must be purchased142. The use of propane would be extremely

effective in cold weather, as it has a lower latent heat of vaporization as compared to

gasoline. The harmful emissions from propane are also much less than gasoline, making

it an attractive alternative fuel143. Finally, it is relatively simple to implement a cold start

system, as a control valve would simply need to be opened before starting, and closed

shortly thereafter.

Gasoline is another cold starting option. The obvious benefits of gasoline include

superior availability, easy portability (a one gallon tank is all that is necessary), and a cost

of $1.61 per gallon144. Additionally, the retrofitting cost would be very minor, as the

139 Propane Gas Facts, 2003, The Energy Source Network, 20 Nov. 2003, <http://www.propanegas.com/>. 140 Alternative Fuels Data Center, The Alternative Fuel Price Report (Dept. Of Energy, 3 Mar. 2003), <http://www.afdc.doe.gov/pdfs/afpr_3_3_03.pdf>. 141 Maureen Shields Lorenzetti, Alternative Motor Fuels: A Nontechnical Guide (Tulsa: PennWell, 1996) 195. 142 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>. 143 Maureen Shields Lorenzetti, Alternative Motor Fuels: A Nontechnical Guide (Tulsa: PennWell, 1996) 136. 144 Alternative Fuels Data Center, The Alternative Fuel Price Report (Dept. Of Energy, 3 Mar. 2003), <http://www.afdc.doe.gov/pdfs/afpr_3_3_03.pdf>.


P2

only components necessary are a portable tank, fuel line, pump, and nozzle145. Gasoline

would readily solve the cold start problem, as most automobiles and boats do not have

difficulty starting at cold temperatures while running on gasoline. Extreme cold may

pose starting problems, but again this is not an issue with boats. The environmental

impact of gasoline is the worst of the cold start options, however as the fuel is injected for

just a few seconds, the amount of gasoline combusted is minimal. Finally, the gasoline

system is extremely easy to use, as squeezing the pump once would be sufficient for cold

weather starting.

Natural gas is yet another potential alternative fuel for cold starting use. Unlike

propane, natural gas has a much lesser distribution network, as there are approximately

1300 natural gas refueling sites across the nation146. Since natural gas is stored in high

pressure cylinders, they can be transported to refueling sites. The fuel cost of natural gas

is $1.20 per gasoline gallon equivalent, the cheapest of the alternative fueling options147.

However, the cost of retrofitting is expensive, as a cold start system would need a high

pressure cylinder, high pressure fuel lines, and a pressure regulator to reduce the gas to

atmospheric pressure. Full vehicle conversions range from $2500 - $4000148, and while

the cost for a cold start system would be less, the use of the aforementioned costly

components makes this the most expensive alternative solution. Similar to propane,

natural gas is an effective solution to the cold start problem, with a low latent heat of

vaporization. Natural gas is extremely environmentally friendly, and has the lowest

145 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>. 146 About Natural Gas, NGV, 19 Nov. 2003, <http://www.ngvc.org/ngv/ngvc.nsf/bytitle/fastfacts.htm>. 147 Alternative Fuels Data Center, The Alternative Fuel Price Report (Dept. Of Energy, 3 Mar. 2003), <http://www.afdc.doe.gov/pdfs/afpr_3_3_03.pdf>. 148 Maureen Shields Lorenzetti, Alternative Motor Fuels: A Nontechnical Guide (Tulsa: PennWell, 1996) 194.


P3

emissions of the alternative fuel options149. However, the natural gas system is not as

simple to use as the propane and gasoline systems, as the valves and controls used to

regulate the high pressure natural gas are somewhat complex.

Hydrogen gas is another potential fuel to solve cold starting issues. Hydrogen can

be transported in tanks or generated from the ethanol fuel. A large problem is the

availability of hydrogen; there is only a handful of hydrogen refueling sites across the

country150. Additionally, as the process of making hydrogen is somewhat expensive, the

cost is prohibitive. Thus, the focus is shifted to using hydrogen which has been internally

generated from the ethanol fuel. This eliminates problems associated with availability

and fuel cost, but generates new problems in other areas. The cost of retrofitting a system

to include a hydrogen reformer is extremely high. While this could potentially be done at

the production stage (at great cost; vehicles with reformers cost significantly more than

those without), to retrofit a gas engine would be extremely difficult, not to mention

incredibly expensive. Also, any hydrogen reformer system would be complicated to

operate for the average recreational boat user. The addition of hydrogen would be an

effective solution to the cold start problem, as hydrogen does not need to be vaporized

and burns easily in cold temperatures151. The environmental benefits of hydrogen are

obvious, as the gas is extremely clean burning152.

149 Maureen Shields Lorenzetti, Alternative Motor Fuels: A Nontechnical Guide (Tulsa: PennWell, 1996) 116. 150 Alternative Fuels Data Center, Alternative Fuel Station Counts Listed by State and Fuel Type (Dept. Of Energy 1 Dec. 2003), <http://www.afdc.doe.gov/refuel/state_tot.shtml>. 151 Dr. Gregory W. Davis, Development of Technologies to Improve Cold Start Performance of Ethanol Vehicles, 11 June 2001, Kettering University, 20 Nov. 2003, <http://www.michiganbioenergy.org/pubs/coldstart.pdf>. 152 Energy Efficiency and Renewable Energy, Why Are Hydrogen and Fuel Cells Important, 28 Jan. 2003, U.S. Dept. of Energy, 20 Nov. 2003, <http://www.eere.energy.gov/hydrogenandfuelcells/hydrogen/why.html>.


P4

Like hydrogen, diethyl ether can be produced from the ethanol itself. There are

no concerns with portability, fuel cost, availability, etc. There are similar problems as

with hydrogen. To convert ethanol into diethyl ether, a catalyst is needed. A modified

catalytic converter, equipped with an alumina based catalyst to convert the ethanol,

would have to be designed and installed. This would likely come at a high cost, if such a

device is even commercially available. Diethyl ether would solve the cold start problem;

the vapor pressure is similar to gasoline. The environmental impact would be similar to

ethanol, however the conversion of ethanol to diethyl ether could potentially create

ethylene, which when converted into ethylene oxide is a toxic emission153.

Another source of diethyl ether is through a cold-starting aid commonly sold in

automotive stores. It is highly portable (as it is sold in a can the size of a spray paint

can), and is affordable at approximately $2. Additionally, the ether is extremely effective

at achieving ignition and preheating the engine, as it is used as a cold starter for gasoline

engines at very cold temperatures. Other benefits include the minimal retrofitting cost

(just buy the can), ease of use (simply requires a short spray into the air intake on the

carburetor, which is easily accessible), and its repeatability as a single canister contains

enough ether for countless starts. The environmental impact of the ether is similar to the

above ethanol-produced diethyl ether.

An electric heater connected to an outlet is one possible option for heating the

ethanol in the carburetor before it is ignited154. Portability is a major problem here, as the

engine must be near an outlet for the heater to operate. While outlets are readily

153 Tomoko Kito and Scott Cowley, Generation of Diethyl Ether in an Ethanol Vehicle System for Cold-Start Assistance, 22 Nov. 1996, Colorado School of Mines, 20 Nov. 2003, <http://www.mines.edu/research/cifer/research/coldstart.html>. 154 Roger Lippman, How to Modify Your Car to Run on Alcohol Fuel, April 1982, U.S. Dept. of Energy Appropriate Technology, 20 Nov. 2003, < http://terrasol.home.igc.org/alky/alky2.htm>.


P5

available at marinas, boats kept on moorings and out on the lake would not have access to

these outlets. Thus, if you turned off your engine in the middle of the lake, and the

temperature of the engine dropped, you could be stranded! The cost of the electricity is

minimal, usually free, as most marinas do not charge for use of their electrical outlets.

The retrofit cost would also be minor, as no additional tanks or lines would be needed;

simply an electric heater, placed near or around the carburetor. While this system would

be effective in starting the engine in cold weather, it is not as effective as the alternative

fuel options, due to the time required to heat the ethanol. While the other options

combust immediately, the electric heater would take some time to warm the fuel for

combustion. The environmental impact would be nonexistent, as no additional emissions

or pollutants would result from the electric heater use. Finally this system would only

require plugging a cord into an outlet; far and away the simplest cold start system to use.

The final option is an electric heater powered by a battery. As heaters draw on a

lot of power, this battery would likely be the boat’s battery used to power the onboard

electrical systems. This eliminates the portability problem, as wherever the boat goes, the

battery goes. Availability is not a major concern, as most boats have batteries, however

smaller boats may use an outboard engine but not a battery. Costs are almost identical to

that of outlet electric heaters; however the retrofitting cost may be slightly higher, as

modifications would have to be made to connect an electric heater to a boat battery.

Additionally, there would have to be an easily accessed on/off switch, as disconnecting

the heater from the energy source (the battery) would pose potential electrocution risks,

especially in the presence of water. This system would have the same effectiveness

problem as the other electrical heater – the time to heat the ethanol for combustion.


P6

However, the battery powered heater has another potential problem, in that it draws

electricity from the battery, and could potentially drain the battery. This would be a

major problem, as boat batteries are essential to operation, and relatively costly to

replace155. While the other cold start solutions are very repeatable, as they involve the

use of a fuel, the battery’s potential to be drained makes this option the least repeatable of

the options. Finally, this system would be very easy to operate, as it would involve

turning the heater on and off.

155 Nautical Know How Inc., Marine Battery Primer, 28 Aug. 2000, 20 Nov. 2003, <http://www.boatsafe.com/nauticalknowhow/marine_battery.htm>.


Q1

Appendix Q. Idle Speed Emissions Testing

Unlike the other throttle settings, idle speed is independent of the size of the main

jet. This is due to the diverted fuel flow into the idle jet during idling. To optimize the

carburetor for the fuel, the idle screw allows adjustment until the RPM’s are maximized.

For gasoline, this constitutes a 3.5 turn counterclockwise from tightened position. After

experimentation using a tachometer to measure RPM’s, the ideal setting for ethanol was

determined to be 1 turn counterclockwise. The emissions for gasoline and ethanol in

their respective ideal idle screw settings are presented in the following graphs.

Hydrocarbon and NOx Emissions

803.8

164.5

0100200300400500600700800900

Gas EtOH

Fuel

PPM Idle Throttle

Figure 23. Hydrocarbon and NOx Emissions


Q2

Figure 24. CO and CO2 Emissions

For both sets of emissions, there is a dramatic improvement associated with the

use of ethanol over gasoline. Total hydrocarbons and NOx are greatly reduced, as is the

CO%. CO2% increases considerably, representing an increased efficiency associated

with ethanol operation. This is due to the fine-tuning of the idle screw setting, which is

impossible during operation in the other throttle ranges, explaining their lower CO2

values.

CO and CO2 Emissions

0.00%2.00%4.00%6.00%8.00%

10.00%12.00%14.00%16.00%

Gas EtOHFuel

% Idle Throttle CO%Idle Throttle CO2%


R1

Appendix R. Tohatsu Power Curve

Figure 25. Power curve for Tohatsu 5 hp four-stroke outboard engine156

156 Garland Lewis, Tohatsu, “FW: Tohatsu,” email to author, 27 Feb 2004.


S1

Appendix S. Mid-throttle Power Testing

A thermodynamic analysis of the cooling water was used to estimate the power at

mid-throttle. The outboard engine was water-cooled: water from the bucket was sucked

up, heated by the engine and discharged into a different bucket. The engine initially ran

for twelve minutes to allow it to warm up. Thermometers were used to determine the

temperature of the “cold” and “hot” cooling water. The hot discharged water filled a

beaker for 10 seconds and then the volume was measured. From this data, the volumetric

flow rate could be obtained. This procedure was repeated for the gasoline engine and for

the four different main jet sizes for ethanol.

The thermodynamic analysis of the water temperature change made the

assumption that the power of the engine caused the heat rate that raised the temperature

of the water. The following equation was used to calculate the power:

TcQP p∆= ρ)80.0( Eq. 3

where is the power in kW, Q is the volumetric flow rate in m3/s, ρ is the density of

water (998 kg/m3), cp is the specific heat of water at constant pressure (4.2 kJ/kg-

K),157 and ∆T is the temperature change in K

The value was multiplied by 0.80 to attempt to account for energy lost in this conversion

to bodies other than the water. The power was subsequently converted into hp.

157 Michael Moran and Howard Shapiro, Fundamentals of Engineering 4th Ed. (New York: Wiley, 2000).


S2

Power at Mid-Throttle

1.42

1.561.51

1.07

1.42

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8


Pow

er (h

p)

Figure 26. Power at Mid-Throttle

As one can see from reviewing the results, the power obtained through this

method was pretty consistent. It appeared to be independent of the fuel or jet size.

Additionally, upon comparison to the Tohatsu power versus RPM curve for gasoline, the

power at 4600 RPM should be approximately 4.5 hp. Most likely, the engine’s internal

thermometer regulates the temperature of the engine, and this method could not provide

an accurate representation of the power output at mid-throttle.


T1

Appendix T. Maximum RPM Values

Maximum RPM values

6230

5900

6300 6300

6000

5700

5800

5900

6000

6100

6200

6300

6400


RPM

Figure 27. Maximum RPM values


U1

Appendix U. Efficiency at Mid-Throttle To calculate the fuel efficiency of the gasoline engine, a known volume of fuel

was run in an engine over a known amount of time. In more auspicious conditions, the

engine could be mounted on a boat and run, which could also include a distance term.

However, due to a lack of these resources, the engine was tested on neutral in the

described test set up. Initially, the methodology consisted of filling the entire tank with

gasoline and running the engine on neutral, while timing, until it eventually would run

out of fuel. This methodology proved ineffective, as this process was very time

consuming for relatively few data points.

Next, a small quantity of gasoline, 50 ml, was run until the engine would run out

of fuel. This methodology also was ineffective, as the known quantity of fuel was not

large enough to allow the engine to run for longer than a short period of time. Upon

closer examination of the fuel system, unmeasured fuel was found in the carburetor and

fuel lines, which would potentially alter efficiency data. The same was attempted for a

larger quantity, 250 ml, but a similar result occurred.

Finally, a moderate amount of fuel was chosen, 500 ml, and run at both mid- and

full-throttle until the engine would run out of fuel on the loading dock of Thayer School

of Engineering. This methodology was successful in that the engine ran for a significant

amount of time before running out of fuel. The remaining quantity was measured, the

difference taken from the initial quantity, and divided by the run time. To gather multiple

points, several runs were performed six times, when consistent data was noticed. The

first data point was disregarded, and considered as a ‘warm up’ period for the engine, and

also so the first data point is taken under similar conditions as the subsequent runs.


U2

For ethanol, fuel efficiency can vary greatly with our final modification design.

For each jet size, a similar fuel efficiency methodology was implemented, where 600 ml

was used to offset the potential fuel efficiency decrease. After two runs, it was decided

that the fuel efficiency decrease had no significant impact and 500 ml was used for the

remainder of the runs for each jet size.

The results of the fuel efficiency tests are depicted below. Here, data is

represented only as a volume per time. For a basis of comparison between fuels, which

can have varying power outputs, the fuel efficiency term can also be manipulated to

include a power term. However, because of the inability to measure horsepower on a

marine outboard of low horsepower, the calculation for the efficiency per power will be

discussed in the next section.

Mid-throttle Fuel Efficiency

0

0.05

0.1

0.15

0.2

0.25

0.3

Gas -0.028"diam

EtOH -0.028"diam

EtOH -0.0336"

diam

EtOH -0.0364"

diam

EtOH -0.0392"

diam

Fuel and Jet Diameter Size (in.)

Fu

el

Eff

icie

ncy

(gal/

hr)

Figure 28. Mid-throttle Fuel Efficiency


V1

Appendix V. Project Budgetary Assessment The overall budgetary assessment of the ENGS190/ENGG 290 project consists of all the

costs associated with the project including the engine and engine parts purchased, travel

costs, and the cost of parts for modification. Below is table of our expenditures over the

course of the two terms.

Expense Cost ($)

Engine 1000.00 Test stand construction 35.04 Bucket/1 gal gas tank/pump 14.73 Oil 4.99 Lock 12.99 Travel reimbursement (Jan 5) 75.00 Engine maintenance (Fairlee Marine) 45.00 Mercury fuel tank+line 67.90 Engine manual 54.50 Mercury parts w/o shipping 131.63 Fuel filter 9.99 Ether 1.99 O-rings 33.50 Travel reimbursement (Jan 21) 30.00 Travel reimbursement (Mar 3) 30.00 TOTAL COST 1547.3

Table 15. Budgetary cost for each expense