ibex whelan pres rev5
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EPA Compliant Fuel SystemsIBEX 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
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
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Automotive vs. Marine Fuel Systems
Marine System
-All fittings on topmost surface
-Tank must pass fire test
-Passive purge canister only
-Fuel pump on engine
Automotive System
-Fittings below topmost surface
-Active purge canister system
-Filling event emission limits
-Fuel pump in tank
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?
-Components must be dry
-Must vent freely
Venting
Ullage Reservoir
Definition:
The volume by which a liquid container falls short of being full*
Ullage
*http://dictionary.reference.com/browse/ullage
TANK VOL (cu.in.) TANK VOL ( Gallons)
Min Distance Between Tank Top surface and Fuel (in) (93% OF TOTAL INTERIOR VOLUME)
Max Distance Between Tank Top surface and Fuel (in) (93% OF TOTAL INTERIOR VOLUME)
Tank Wall Thickness (in)
69997.3857 303.01 1.1752 1.4333 0.25
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 303.01 281.80 296.95
Tank Volume (281.80 Ga)(93% of Complete Tank Volume)
Tank Body
Min Distance
Max Distance
Tank Modeling
Tank Orientation (Static)
Tank Tip Study At (98% of Complete Tank Volume)
FRONT DOWN (4°) RIGHT DOWN (2°)
LEFT DOWN (2°)
STATIC POSITION0.3°
RIGHT
LEFT
FRONTREAR
REAR DOWN (4°)
Tip/Vent Study
FUEL ORIENTATION AT VARIOUS TIP STUDY ANGLESLAYERED OVER EACHOTHER.
Iso View
Tank Tip Study – Vapor Space available in various combinations
FRONT & LEFT DOWN
FRONT & RIGHT DOWN
REAR & LEFT DOWN
REAR & RIGHT DOWN
Tip/Vent Study
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
• What different engines may end up on boat model?
• What are the engine manufacturers vacuum requirements?
– Fuel Line Pressure Drop
Current Anti Siphon
12”
Requires 12” of anti-siphon protection (or stop valve)
Elevation “X” to Engine
Engine Fuel line vacuum = X + 12”gasoline + hose routing restriction
Ex. = 32”gasoline+ 12”gasoline+ 9”gasoline= 53”gasoline (1.47psi, 10kPa, 3inHg)
EPA compliant Anti Siphon
12”
Requires 12” of anti-siphon protection (or stop valve)
Elevation “X” to Engine
Engine Fuel line vacuum = X + 12”gasoline + hose routing restriction + YEx. = 32”gas+ 12”gas+ 9”gas+ 10”gas= 63”gasoline (1.75psi, 12kPa, 3.6inHg)
Diurnal Vacuum/ restriction of “Y” in-gasoline
EPA compliant Anti SiphonUllage Tank Example
12”
Requires 30” of anti-siphon protection (or stop valve)
Elevation “X” to Engine
Engine Fuel line vacuum = X + 30”gasoline + hose routing restriction + YEx. = 32”gas+ 30”gas+ 9”gas+ 10”gas= 81”gasoline (2.25psi, 15.5kPa, 4.6inHg)
Diurnal Vacuum/ restriction of “Y” in-gasoline
Ullage Tank18”
Special Note Regarding Fuel Line (for PRV Diurnal Systems)
May require pressure management device
May require rigid fuel lines to engine
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?
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Technical Considerations1) 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
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