Transcript Slide 1

EPA Compliant Fuel Systems
IBEX Sep 28, 2010
Sean Whelan P.E.
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Agenda
1. Which diurnal system should I choose
2. What is Automatic Shut off/no spit back & how do I meet it
3. Automatic shut off in cars & trucks
4. Venting and Thermal Expansion
5. Engine Performance & Fuel Line Pressure Drop
6. Safety Considerations
7. Technical Considerations
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Which Architecture do I choose?
Diurnal Systems (all)
• Can I fit a new tank with diurnal components mounted?
• How do I maintain accessibility of all attachments?
Carbon Canister System
• Can I fit a carbon canister in my boat?
• How do I prevent liquid gas and water from entering the canister?
Pressure Release System
• Can I prevent fuel line from pressurizing or do I need rigid fuel lines?
• Can my new tank assembly withstand the pressure cycles over time?
• Is there room for my tank to swell under pressure without contacting
deck or hull?
• Do I have sufficient pressure drop budget in my engine(s)?
What Is Automatic Shut Off
Automotive Fuel System
– Nozzle shut off feature
Automotive Fuel System
– Nozzle shut off feature
Automotive vs. Marine Fuel Systems
Automotive System
-Fittings below topmost surface
-Active purge canister system
-Filling event emission limits
-Fuel pump in tank
Marine System
-All fittings on topmost surface
-Tank must pass fire test
-Passive purge canister only
-Fuel pump on engine
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Refueling Considerations
• How will the system handle high and low RVP fuels?
• How will the system handle high and low temperature refueling
events?
• Will my boat be compatible with marina fuel fills of larger sizes?
• Will my customer be safe after filling boat with a jerry can?
Venting
-Components must be dry
-Must vent freely
Ullage
Definition:
The volume by which a liquid container falls short of being full*
Ullage Reservoir
*http://dictionary.reference.com/browse/ullage
Tank Modeling
Tank Body
Tank Volume (281.80 Ga)
(93% of Complete Tank Volume)
Min Distance
Max Distance
TOTAL INTERIOR
VOLUME OF TANK
FLUID VOLUME OF TANK (93% OF TOTAL
INTERIOR VOLUME)
FLUID VOLUME OF TANK (98% OF TOTAL
INTERIOR VOLUME)
cu. in.
69997.3857
65097.5687
68597.4380
US
Gallons
303.01
TANK VOL
(cu.in.)
TANK VOL ( Gallons)
281.80
Min Distance Between Tank Top
surface and Fuel (in) (93% OF
TOTAL INTERIOR VOLUME)
69997.3857
303.01
1.1752
296.95
Max Distance Between Tank Top
surface and Fuel (in) (93% OF
TOTAL INTERIOR VOLUME)
Tank Wall
Thickness (in)
1.4333
0.25
Tip/Vent Study
LEFT
Tank Orientation (Static)
REAR
FRONT
0.3°
RIGHT
STATIC POSITION
Tank Tip Study At (98% of Complete Tank
Volume)
FRONT DOWN (4°)
REAR DOWN (4°)
RIGHT DOWN (2°)
LEFT DOWN (2°)
Tip/Vent Study
FUEL ORIENTATION AT VARIOUS TIP STUDY ANGLES
LAYERED OVER EACHOTHER.
Iso View
Tank Tip Study – Vapor Space available in various
combinations
Venting Considerations
• How does my fuel system create ullage?
• How does my system allow for venting at ABYC H24 angles?
• What happens at angles beyond H24?
• How do I prove that my fleet vents safely for every model?
Engine Performance
– Fuel Line Pressure Drop
• What different engines may end up on boat model?
• What are the engine manufacturers vacuum requirements?
Current Anti Siphon
Engine Fuel line vacuum = X + 12”gasoline + hose routing restriction
Ex. = 32”gasoline+ 12”gasoline+ 9”gasoline= 53”gasoline (1.47psi, 10kPa, 3inHg)
Requires 12” of antisiphon protection (or
stop valve)
Elevation “X”
to Engine
12”
EPA compliant Anti Siphon
Engine Fuel line vacuum = X + 12”gasoline + hose routing restriction + Y
Ex. = 32”gas+ 12”gas+ 9”gas+ 10”gas= 63”gasoline (1.75psi, 12kPa, 3.6inHg)
Requires 12” of antisiphon protection (or
stop valve)
Elevation “X”
to Engine
12”
Diurnal Vacuum/
restriction of “Y” ingasoline
EPA compliant Anti Siphon
Ullage Tank Example
Engine Fuel line vacuum = X + 30”gasoline + hose routing restriction + Y
Ex. = 32”gas+ 30”gas+ 9”gas+ 10”gas= 81”gasoline (2.25psi, 15.5kPa, 4.6inHg)
Elevation “X”
to Engine
18”
12”
Ullage
Tank
Requires 30” of antisiphon protection (or
stop valve)
Diurnal Vacuum/
restriction of “Y” ingasoline
Special Note Regarding Fuel Line (for PRV
Diurnal Systems)
May require rigid fuel lines
to engine
May require pressure
management device
Engine considerations
• What different engines may end up on boat model?
• What are the engine manufacturers vacuum requirements?
• What is elevation of engine hook ups?
• Do I have sufficient pressure drop budget for the EPA Diurnal
system I want?
• What is the tank vacuum with EPA diurnal system?
• What is the additional fuel pressure drop with EPA diurnal system?
Safety Considerations
• What is preventing over pressurization of the tank?
• What safety methods and strategies prevent fuel from
entering into the bilge?
• What happens when a customer fills a tank in an extreme
circumstance beyond ABYC & EPA specifications? (i.e.
65°F temperature swing)
• Will the new fuel systems allow engines to operate
properly under all conditions?
• Is there a single component that can cause system to fail
or is there redundancy built in?
Technical Considerations
1) Refueling with no spit-back
2) Engine fuel line pressure drop
3) Hot Fuel Handling
4) Extreme Vessel angles/ attitudes
5) Jerry Can filling event
6) Non-automatic nozzle filling event
7) Vapor Condensation/ liquid accumulation
8) Expected CARB requirements
9) Pressure Lifecycle
10) Fill Level Repeatability
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Summary/ Review
1. Diurnal
2. Refueling
3. Venting
4. Engine Compatibility
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Questions?
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Appendix
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Diurnal Emissions
• What is diurnal?
• What are diurnal emissions?
• How are systems built to reduce emissions ?
– Carbon Canister
– Pressure Release Valve
Carbon Canister Fuel System
Pressure Relief Fuel System