OAR Box 1830 

Prepped by Ollie Stewart 

Document Number: 

9) IV-B-5 

Docket Number: 

A-87-11 

Printed 11/13/2008 7:20:51 AM Sheet 9 of 232 

p.1 
» afmY u UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

\mf* PHS^r 

ANN ARBOR. MICHIGAN 48105 

P.2 

X£ - h -of-

¥~ OFFICE OF 4^ 

AIR AND RADIATION 

JUL 71988 

MEMORANDUM 

SUBJECT: 

FROM: 

TO: 

THRU: 

Displaced Vapor During Refueling 

Karen Lostoski, Mechanical Engineer c^C^ou*^ tfryWy-v-of 

Standards Development and Support Branch 

Chester J. France, Chief 

Standards Development and Support Branch 

John F. Anderson, Senior Project Manager LLP JLA_ 

Standards Development and Support Branch jnfi^/r~J^ 

A study was done to determine the amount of vapor 

displaced from a fuel tank during refueling and how the amount 

of vapor could be reduced. A reduction in displaced vapor 

could be advantageous to the onboard control system by reducing 

the required size of the canister. The entrainment rate 

measured in this testing are given in Table 1. Attachment 1 

describes the test configurations involved and provides more 

details on the testing. 

To summarize, a significant reduction in displaced vapor 

could only be obtained by techniques requiring raising the 

fillneck height to a level which was impractical. Without 

raising the inlet height, the results showed a maximum of 8 

percent reduction in the displaced vapor to liquid ratio. 

Attachments 

5933W 
*

NV,RONMEN^;" 

A^^CTION 

SEP - 2 1988 
P.4 

Table 1 

Displaced Vapor During Refuelinq-Data Summary 

Configuration . 

No of Average Ratio 

Tests (Vapor/Liquid) 

1. Production Fillpipe . 1 

2. Production fillpipe 2 

with check valve 

1.58 

1.46 

Comments 

3. Large diameter pipe 

for fillneck 

1.60 

4. Large diameter pipe 

with inlet raised 

5. Large diameter pipe 

with one screen 

1.56 

1.45 

6. Large diameter pipe 

with two screens 

7. Large diameter pipe 

with one sponge 

8. Large diameter pipe 

with two sponges 

9. Large diameter pipe 

with duckbill 

1.32 

1.59 

1.26 

1.47 

Inlet height must be 

raised to operate 

Need inlet height 15" 

higher than stock 

height to operate 

Inlet height must be 

raised to operate 

Duckbill too inflexible 

to flow properly. Got 

spills 2 of 3 times. 
P.5 

Attachment 1 

Vapor Displaced from Fuel Tank During Refueling 

Equipment 

Tank: Production 1986 Oldsmobile Cutlass 

Fillpipe Configurations: 

a) Production 1986 Oldsmobile Cutlass. 

b) Check valve added to production fillpipe; tank 

vented at fuel pick-up - gage sender unit with valve 

to adjust tank pressure. 

c) 2 1/2" Plexiglass tube (- 3ft. long) or 2 1/2 

rubber hose (- 3ft. long). Same venting as in (b) 

above. 

d) Fillpipe as in (e) above with inserts: sponge 

material, wire mesh (screen) or "duckbill" to reduce 

vapor. 

Testing Procedure 

Fuel from tank empty (tank drained through fuel return 

line at essentially same height as fuel pick-up) to fuel 

tank capacity (approximately 16 gallons, retaining stock 

vapor space of approximately 2-3 gallons). Measure volume 

of vapor displaced. Tank temperature and dispensed fuel 

temperature at temperature of refueling bay (55° to 

60°F). Evaluate methods for reducing volume of vapor 

displaced. 

Results Summary 

a) Two sections of sponge material in series reduced 

displaced vapor volume by 25 percent to 30 percent; 

fillneck head height required - 3 ft. 

b) Single sponge element provided no benefit; fillneck 

height of almost 3 ft required. 

c) Dual flat screens reduced displaced vapor volume by 

20 to 25 percent; almost 3 ft fillneck height 

required. 

d) Single flat screen and folded screen reduced 

displaced vapor volume by 5 to 10 percent. 

e) Duckbill did not substantially affect displaced 

vapor volume when mounted at either top or middle of 

fillneck. When mounted at bottom of fillneck 

reduced displaced vapor volume by about 5 percent. 

Difficulties experienced with achieving fueling 

because duckbill tended to restrict fuel flow; i.e., 

a fillneck head height greater than 3 feet was 

required to achieve fueling at 10 gpm. 
Displaced Vapor During Refueling 

P.6 

1. Large diameter pipe (to see if you get liquid-vapor separation). 

Fill inlet height (end of large diameter pipe) at approx. stock 

fillneck height. 

Gas In Vapor Out 

(gallons) (ft3)(gallons) 

16.1 

16.0 

3.479 

3.349 

26.03 

25.05 

Ratio 

(Vapor/ 

Liquid) 

1.62 

1.57 

Flow Rate 

(gpm) 

10 

10 

2. Fill inlet raised (approx. 30° pitch) 

Ratio 

Gas In Vapor Out (Vapor/ Flow Rate 

(gallons) (ft3)(gallons) Liquid) (gpm) 

16.1 3.550 25.06 1.56 10 

Tank 

Pressure ("Hg)* 

.02 

.02 

Tank 

Pressure ("Hg) 

.02 to .03 

3. Production fillpipe with check valve added just outside of the 

tank 

Ratio 

Gas In 

(gallons) 

16.0 

16.0 

4. Screen 

Gas In 

(gallons) 

16.0 

16.05 

Vapor Out 

(ft3)(gallons) 

3.146 23.54 

3.122 23.36 

in fill neck (fo 

Vapor Out 

(ft3)(gallons) 

3.123 23.36 

3.046 22.79 

without screen: 

16.1 3.391 25.37 

(Vapor/ 

Liquid) 

1.47 

1.46 

lded screen). 

Ratio 

(Vapor/ 

Liquid) 

1.46 

1.42 

1.58 

Flow Rate 

(gpm) 

10 

10 

Tank 

Pressure ( 

.20 

.20 

!' 

.20 

Tank 

Pressure ("Hg) 

.02 

.02 

'Hg) 

Approximately 10 percent less vapor with screen in place. Bubbles 

appear to coalesce at screen with liquid and vapor streams entering 

tank rather than froth. 

* Tank pressure values are average values during tank fill and do 

not include any spikes at the start or end of the fill. 
P.7 

5. Sponge in fill neck (two sections of foam separated by. about 1, 

to 1 1/2 inches) 

Ratio 

Gas In £ Vapor Out (Vapor/ Tank 

(gallons) (ft3)(galIons) Liquid) Pressure ("Hg)

 : 

16.0 2.588 19.36 1.21 .04 

<Tube full of foam (fuel + bubbles). 

6. Screen (single flat piece) in fill neck. 

Ratio 

Gas In Vapor Out (Vapor/ Tank 

(gallons) (ft3)(gallons) Liquid) Pressure ("Hg) 

16.0 3.155 23.60 1.47 .40 

Liquid/foam interface at screen. Vent valve totally open. 

7. Duckbill in fill neck. 

a) Duckbill mounted at top of fill neck, nozzle shut-off port below 

exit from duckbill. 

• i 

Ratio 

Gas In Vapor Out (Vapor/ Tank 

(gallons) (ft3)(gallons) Liquid) Pressure ("Hg) 

16.0 3.219 24.08 1.50 .30 

b) Duckbill in lower half of fill neck. 

Ratio 

Gas In Vapor Out (Vapor/ Tank 

(gallons) (ft3)(gallons) Liquid) Pressure ("Hg) 

2.4 .478 3.576 1.49 

Spitback! Duckbill has to be moved lower in fill pipe. 

c) Duckbill in lower section of fill neck. -

Ratio 

Gas In Vapor Out (Vapor/ Tank 

(gallons) (ft3)(galIons) Liquid) Pressure ("Hg) 

7.4 1.413 10.57 1.43 

Spill at 5.2 gals and at 7.4 gals. Duckbill too inflexible to 

flow properly. 
P.8 

V 

I 

8. Sponge (single unit) in plexiglass tube. 

Ratio 

Gas In Vapor Out (Vapor/ Tank 

(gallons) (ft3)(galIons) Liquid) Pressure ("Hg) 

7.0 1.585 11.86 1.69 

Tripped repeatedly (8 times). Exit valve totally open. 

9. Sponge (single unit) at bottom of tube. 3 foot rubber tube. 

Inlet of tube about 15" higher than stock fill neck. 

Ratio 

Gas In Vapor Out (Vapor/ Tank 

(gallons) (ft3)(gallons) Liquid) Pressure ("Hg) 

13.0 2.592 19.39 1.49 .14 

10. Two sponges in bottom of 3 ft plexiglass tube. 

Ratio Top of 

Gas In Vapor Out (Vapor/ Fillneck Tank 

(gallons) (ft3)(qallons) Liquid) Height (in) Pressure ("Hg) 

16.0 2.791 20.88 1.30 37 .30 

16.0 2.701 20,206 1.26 39 

Liquid-vapor foam fills the tube and causes repeated shut-off. 

Raising fillneck height helped; , gave only one shut-off. 

11. Two screens (flat pieces separated by approximately 1 inch) in 

bottom of 3 ft plexiglass tube. 

Fillneck height to bottom of tank = 39 inches. 

Ratio 

Gas In Vapor Out (Vapor/ Tank 

(gallons) (ft3)(galIons) Liquid) Pressure ("Hg) 

16.0 2.705 20.24 1.26 .30 

16.0 2.962 22.16 1.38 .34 

Height of liquid-vapor foam in fillneck was higher in second run.