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High Ethanol Fuel Endurance Advanced Engineering Project


High Ethanol Fuel Endurance Advanced Engineering Project A study of the effects of running 15% ethanol concentration in current production 4-stroke engines ... – PowerPoint PPT presentation

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Title: High Ethanol Fuel Endurance Advanced Engineering Project

High Ethanol Fuel Endurance Advanced Engineering
  • A study of the effects of running 15 ethanol
    concentration in current production 4-stroke
    engines and legacy 2-stroke engines.
  • Prepared By
  • Dave Hilbert

  • This project is a cooperative effort to assess
    the feasibility of increasing the allowable
    ethanol concentration in gasoline above the
    current legal limit of 10 for use in marine
  • Objectives of this project
  • Run 300 hours of wide-open throttle endurance on
    3 engine families and measure emissions at 0,
    150, and 300 hours.
  • 9.9HP 4-stroke carbureted, 200HP 2.5L 2-stroke
    EFI (represents legacy product) and 300HP L6SC
    Verado engines were chosen.
  • Two engines from each family
  • Test engine operated on E15
  • Control engine run on pure gasoline

Test Engine Specifications
Results Summary
  • Verado
  • Initial E15 engine generated HCNOx emissions in
    excess of FEL when operated on E15 fuel.
  • E15 engine failed exhaust valves. Metlab
    analysis showed excessive metal temperatures
    caused a reduction in fatigue strength.
  • F9.9HP
  • The E15 engine on E15 fuel showed high HC
    variability at the post-endurance emissions
    testing. It is believed that this engine was
    misfiring at idle due to the lean operation.
  • The E15 engine showed evidence of hotter metal
    temperatures due to carbon deposits, etc.
  • The E15 engine showed signs of gasket
    deterioration on the fuel pump.
  • 200HP EFI 2.5L 2 Stroke
  • E15 engine showed no difference in emission
  • E15 engine failed the rod bearing. Root cause is
    indeterminate due to the degree of damage.
  • How does ethanol affect oil dispersion in two
    stroke engines?
  • Other than the bearing failure, the end of test
    teardown and inspection did not show any
    significant difference between the 2 engines

Results Summary-Continued
  • 4.3L V6 ECT Mercruiser
  • Two emissions tests were performed on a 4.3L
    catalyzed sterndrive engine to compare the E0
    fuel and the E15 fuel. No durability testing was
    completed on the 4.3L engine with E15 fuel.
  • This testing was not part of the contract, but
    was performed due to the fact that the E15 test
    fuel and a catalyzed engine were readily
    available on the dyno. Also, it compliments the
    testing on a 4.3L carbureted engine done by Volvo
  • EGT increased 20C and catalyst temperatures
    increased 32C at Mode 1 (WOT).
  • Valvetrain durability and catalyst system
    deterioration concerns.
  • Fuel consumption increased by 5 (mass-based
    fuel flow) in closed loop operation.
  • Aside from HC and CO reductions at Mode 1 (open
    loop), the E15 fuel afforded no real benefit to
    reduced emissions overall.
  • NOx increased at Mode 1, but not as much as HC
    decreased for a slight overall reduction.
  • HC, NOx and CO in closed loop operation are
    essentially unchanged between the 2 fuels.
  • Overall
  • The CO emissions were lower on all engines with
    E15 fuel due to leaner running (as would be
  • Fuel analysis showed the E15 fuel that was used
    in testing was in line with expectations.

Conclusions and Recommendations Summary
  • Despite the limited scope of project several
    significant issues were discovered.
  • Durability Failures
  • Emissions Issues (elevated NOx, HC variability)
  • Run Quality due to Lean Operation
  • More testing is necessary to understand effects
  • Driveability- Ex. cold and hot start, transient
    accel/decel, boiloff, etc.
  • Oil dispersion in 2 stroke engines
  • Storage (phase separation, corrosion, etc.)
  • Test program was a cursory look at the effects of
  • Sample size was insufficient to have statistical
  • WOT operation only-masks effects of true customer
    duty cycle

Fuel Comparison
Fuel Comparison
F9.9HP 4-Stroke Emissions
  • Variability on E15 Engine is a concern.
  • E15 fuel-zero hour and EEE-E0 fuel 150 hour
    checks are likely due to run-to-run variability.
  • E15 fuel-300 hour variability is due primarily
    from Mode 5 (idle) HC emissions.
  • Trends on EEE-E0 fuel are consistent between the
    2 engines.

F9.9HP 4-Stroke Emissions
  • Both engines had a tendency to run leaner at
    Modes 4 and 5 with increasing endurance time.
  • The combination of the inherent leaner operation
    and the E15 fuel was enough to cause
    misfires/poor combustion at idle.
  • The misfires caused the HC emissions to increase
    and become highly variable.

F9.9HP 4-Stroke Emissions
  • The fact that the E15 fuel emissions tests show
    that HC emissions increase with leaner mixtures
    supports the misfire theory.
  • The graph below shows HC vs. equivalence ratio at
    idle for every emissions test performed on engine
    0R352904, which is the E15 engine.
  • All E15 fuel emissions tests are shown in red
  • All EEE-E0 fuel emissions test are shown in blue

F9.9HP 4-Stroke Teardown and Inspection
  • More carbon deposits on intake valves of E15

F9.9HP 4-Stroke Teardown and Inspection
  • More carbon deposits on intake port of E15 engine.

F9.9HP 4-Stroke Teardown and Inspection
  • More carbon deposits on piston undercrown and
    rods of E15 engine.

F9.9HP 4-Stroke Teardown and Inspection
  • The gasket showed signs of deterioration on the
    E15 engine compared with the E0 engine.
  • The gasket on the E15 engine had a pronounced
    ridge formed in the area that hinges when the
    check valve is in operation
  • The E15 gasket material in the area that seals
    the check valve also had signs of wear that were
    more advanced than the E0 gasket.

F9.9HP 4-Stroke Teardown and Inspection
  • Material transfer from gasket to diaphragm in
    mechanical fuel pump.


Verado Testing
  • Summary / Review
  • Verado E15 Engine
  • Initial emissions tests on E15 fuel generated
    HCNOx values in excess of the FEL set for this
  • Three-run average on E15 fuel HCNOx 25.6
  • FEL set to 22.0 g/kw-hr
  • E15 engine failed the exhaust valves.
  • High cycle fatigue due to elevated temperatures

Verado E15 Valve Failure Investigation
Cylinder 3 Bottom Valve
Cylinder 3 Top Valve
Cylinder 6 Top Valve
Verado E15 Valve Failure Investigation
Cylinder 3 Bottom Valve
Verado E15 Valve Failure Investigation
  • The failed valves were checked for hardness and
    the values were low.
  • Valves from other E0 engines w/o failed valves
    were measured and the hardness values were within
    expected values.
  • Brand new valves were also measured for

Verado E15 Valve Failure Investigation
  • The new valves that were hardness checked were
    then oven-aged for 24 hours and the hardness was
    checked again.
  • A simple linear interpolation would indicate the
    E0 valve temperature was around 780C and the E15
    valve temperature was approx. 890C or higher.
  • The measured change in exhaust gas temperature
    was only 25-30C.

200HP EFI 2.5L Two-Stroke Testing
  • There was more variability in HCNOx on the E0
    engine than any of the changes on the E15 engine.
  • The trend of CO emissions change vs. endurance
    time was similar between the 2 engines.
  • The rod bearing failure on the E15 engine
    prevented completing the testing.
  • Due to the extensive damage, the cause of the
    bearing failure could not be definitively
  • Assembly error causing a step at the rod / cap
  • If so, why did it run 250 hours of WOT?
  • What effects would the ethanol have on oil

200HP EFI 2.5L Two-Stroke Emissions
200HP EFI E15 Engine-Bearing Failure
  • Root cause of bearing failure is unknown.
  • 283 total engine hours, 256 WOT endurance hours
  • No rollers were recovered.

Remaining Pieces from Cyl 3 Rod Bearing Cage
Undamaged Bearing
Undamaged Rod Rod from Cyl 3
Additional Testing-4.3L V6 ECT Fuel Comparison
  • Increase in EGT of 20C, increase in catalyst
    temperature of 32C at Mode 1.
  • No appreciable difference in emissions during
    closed loop operation.
  • Changes in HC and CO at Mode 1 are expected due
    to lean operation.
  • The increase in catalyst temperature at WOT will
    cause more rapid deterioration of the catalyst
    system leading to higher exhaust emissions over
    the lifetime of the engine.
  • Increase in fuel consumption (mass basis) of 5
    in closed-loop operation.
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