Ethanol as Fuel for Recreational Boats

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Ethanol as Fuel for Recreational Boats
www.mercurymarine.com

• ENGS 190/ENGG 290 Final Report
• Sponsor Professor Charles Wyman
• Group Members
• Erik Dambach, Adam Han, Brian Henthorn
• www.dartmouth.edu/ethanolboat

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Presentation Outline

• Need Statement and Background
• Engine Choice and Modifications
• Specifications and Testing
• Marketability
• Conclusions
• Acknowledgements

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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.

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Why Ethanol?

• Recreational boating with gasoline as a fuel is a
  major source of pollution for both water and air
• Ethanol, unlike gasoline, is biodegradable and
  low in toxicity
• Ethanol is comprised of much fewer chemicals than
  gasoline
• As an additive, the use of ethanol as a fuel has
  the ability to allow for cleaner combustion and
  to lower air emissions
• Ethanol is a renewable source of energy

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State of the Art

• The use of ethanol as a fuel has mainly been
  focused on the automotive industry
• There are limited studies of alternative fuels
  in boating applications
• Fuel ethanol has never been researched for
  recreational boating
• Ethanol was investigated along with other
  alternatives in use to strengthen fuel choice

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Alternative Fuels for Gasoline Marine Engines
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California Case Study

• US fuel prices and regulations vary by region
• Toughest emission regulations in country
• High price of gasoline
• Supportive of alternative fuel technology
• Phase-out of MTBE ? replaced with EtOH
• 2nd most registered number of boats in US
• Discourages the use of carbureted two-strokes

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California Case StudyProjected Price Range for
Ethanol Sale in California at Marinas
Price per gallon of ethanol
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Engine Overview

• 2000 Mercury 5 hp Four-Stroke Outboard
• Four-stroke for smaller needs (
• Necessary Modifications
• Materials Compatibility
• A/F ratio
• Cold-start

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Materials Compatibility

• Rubber Tubing, O-Rings
• Soaked in EtOH
• Tubing replaced with
• Viton B
• O-rings replace with Butyl

Dupont Dow Elastomers Chemical Resistance Guide
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Replacement of Rubberin Fuel System
Tubing
Fuel pump o-ring
Intake manifold o-ring
Drainage screw o-ring
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Materials Compatibility

• Rubber Tubing, O-Rings
• Soaked in EtOH
• Tubing replaced with
• Viton B
• O-rings replace with Butyl
• Fuel Filter
• Soak in EtOH
• Not needed to be replaced
• Metal Corrosion
• Determine primary metal in Fuel System using EDS
  on SEM

Dupont Dow Elastomers Chemical Resistance Guide
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Energy-dispersive X-Ray Spectroscopy (EDS)
Main Jet - Brass
Fuel Pump Aluminum
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Carburetor
Source Mercury Service Manual, 4/5/6HP 4-Stroke
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Carburetor Modifications

• Enlarge Main Jet inner diameter by 20-40
• (.033, .036,.039)

Main Nozzle
Main Jet
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Cold-start Solutions
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Other Important Modifications

• Ignition Timing
• Advance ignition timing for EtOH
• Unfortunately, not possible with Mercury outboard
  engine
• Compression Ratio
• Increase (8.51?111)
• Extremely expensive
• Can only be drastically altered at production
  stage

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Target Specifications
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Testing Methodology
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Testing Methodology
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Testing Setup

• Preparation for testing
• Construct test stand
• Break in engine
• Fuel Used
• Gasoline Shell 87 Octane Unleaded
• Ethanol Ethanol with Natural Gasoline Denaturant
  (2-5)
• Testing Facilities
• Emissions testing at Vermont Technical College
• Thayer School Ice Lab
• Thayer School Loading Dock

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Emissions Testing

• Snap-on MT3505 Emissions Analyzer
• Emissions Analyzed
• Hydrocarbons
• NOx
• CO
• CO2
• Tested at each throttle range (idle, mid, full)
• Tested at each jet size (.028, .033, .036,
  .039)

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Emissions Testing Results

• Full and Mid-throttle testing
• Idle is independent of main jet size
• EtOH had dramatic reductions in emissions at
  .033 jet size

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Emissions Testing Results

• CO emissions
• Increase using EtOH
• Engine not optimized for EtOH combustion
• Lower CO2 values
• .033 jet similar to gas emissions

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Power Testing

• Power Calculated using
• Torque 4.22ft-lb at full throttle running on
  gasoline
• 5 horsepower
• .033 jet
• .036 jet

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Fuel efficiency testing

• Put in known amount of fuel (500 mL)
• Run until the engine stopped
• Record run duration time
• Measure amount of remaining fuel

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Fuel Efficiency with Power

• Divide fuel efficiency by power output
• .036 jet size
• closest to gasoline efficiency
• .028 jet size (original optimized for gasoline)
• Did not sustain combustion of EtOH

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Cold-start Testing

• Gasoline Benchmark
• Location Cold room in ice lab,
• Engine temperature monitored with Fluke IR
  Thermometer
• Cold room initially at 20F
• Warm cold room and engine gradually
• Results
• Below 30F, engine did not start
• At 30F, engine started with much difficulty,
  requiring 15 pulls of recoil starter rope

• EtOH Testing
• Location Loading dock
• Minimized difference between
• Results
• Engine would not start at 30F without cold-start
  assist
• Ether-assist achieved ignition in four
  applications (pull of starter rope couple with
  ether spray into carburetor)
• EtOH engine with cold-start achieved ignition
  quicker than gasoline-powered engine

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Determination of Optimal Jet Size

• .033 and .036 jet sizes determined optimal
  air-fuel ratio
• .033 preferred due to reduced emissions,
  slightly reduced efficiency

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Engine Economic Analysis

• Actual modification cost relatively minor
• Rubber replacements relatively inexpensive
• Labor costs significant, but within specification
• EtOH fuel costs for 60gal/yr increase from 101
  to 141 compared to gasoline

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Target vs. Actual Specifications
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Engine 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.
  
• -Randy Stratton, The Stratton Group
• Although there are a lot of environmentally-consci
  ous people, they are often unwilling to pay
  anything extra.
• -Chris Virgo, mechanic at North Tahoe Marina

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Timeline for ENGS 190
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Timeline for ENGG 290
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Project Conclusions

• Ethanol was found to out-perform gasoline
  environmentally for water and air pollution in
  recreational boating applications
• Ethanol as a fuel has high potential given the
  infrastructure, fuel cost, and environmental
  policy trends
• A four-stroke outboard engine was successfully
  modified to run on ethanol fuel
• Testing of the engine running on ethanol showed
  similar performance in terms of power, varied for
  emissions, and decreased fuel efficiency
• Website www.dartmouth.edu/ethanolboat

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Recommendations

• Obtain dynamometer for engines of low hp to
  strengthen existing data
• Determine optimal jet size between 20 and 30
• Alter compression ratio/timing to further
  optimize the engine at manufacturer level
• Research effects of ethanol materials and
  potential long-term replacements to increase
  longevity of engine
• Use findings to further ethanol-fueled engine
  research

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Acknowledgements

• 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
• 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

• At Thayer School
• Prof. Charles Wyman
• Prof. John Collier
• Prof. Robert Graves
• Doug Fraser
• Gary Durkee
• Thayer School Instrument Rm
• Thayer School Machine Shop
• Paula Berg
• Prof. Benoit Cushman-Roisin
• Prof. Horst Richter
• Joan Levy
• Cathy Follensbee
• William Cote
• Bin Yang
• Daniel Iliescu
• Daniel Cullen