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Februar y198 0 Recommendatio n on Feasibilit y for Onboard Refueling Los s Contro l

NOTIC E Technica l Report s d o no t necessaril yrepresen t fina l EPAdecision s o r positions . Theyar e intended t o presen t technica l analysi s o f issue s usin

g dat a whic har e currentl yavailable . The purpos e in th e releas e o f suc hreport s i s t o facilitat e th e exchang e o f technica l informatio n an d t o infor

mthe publi c o f technica l devel
opment s whic hma

yfor m the basi s fo r a fina l EPAdecision , positio n o r regulator

yaction . Standard s Developmen t an d Suppor t Branc h Emissio n Contro l Technolog yDivisio n Offic e o f Mobil e Sourc e Ai r Pollutio n Contro l Offic e o f Air , Nois e an d Radiatio n U.S . Environmenta l Protectio n AgencyP. 3

I . Introductio n Gasolin e refuelin g losse s estimate d t o b e i n th e rang e o f 4- 5 g/gallon , ca n b e controlle d byus e o f contro l equipmen t a t th e servic e statio n (Stag e I I control ) o r b yus e o f contro l equipmen t i n th e vehicl e (onboar d control) . A s require d byth e 197 7 amend
ment s t o th e Clea n Ai r Act , th e Emissio n Contro l Technolog yDivi

sio n (ECTD ) o f EP Aha s reviewe d and analyze d availabl e dat a o n th e feasibilit yand desirabilit yo f onboar d refuelin g los s contro l whic hwil l b e discusse d i n thi s report . II . Summar yo f Conclusion s an d Recommendation s Severa l hardwar e demonstration s an d pape r studies , Ref . 1 , 2 , hav e bee n conducte d t o determin e th e technica l feasibilit yand cos t effectivenes s o n onboar d refuelin g los s control . Muc ho f th e curren t informatio n i s fro mth e America n Petroleu mInstitut e (API ) onboar d demonstratio n program , Ref . 3 . Othe r curren t informatio n wa s obtaine d fro mmoto r vehicl e manufacturer s i n respons e t o a Jun e 27 , 197 8 Federa l Registe r (43F R 27892 ) reques t fo r relevan t infor

mation . Thes e demonstration s and analyse s dea l wit hth e state-of
the-ar t emissio n contro l technology . Analysi s o f thi s informatio n support s th e followin g conclu
sion s : 1 . Onboar d refuelin g los s contro l i s feasibl e fo r light

dut yvehicles . 2 . Th e mos t probabl e contro l syste muse s hydrocarbo n adsorp
tio n o n charcoa l (th e sam e strateg ytha t i s use d fo r evaporativ e emissio n control) . 3 . Contro l effectivenes s ca n b e a s hig ha t 97% , bu t thi s depend s especiall yupo n th e vehicl e fillpipe/servic e statio n nozzl e interfac e and upo n contro l technolog ydesign . 4 . A n analysi s o f dat a fro mthre e fillpipe/nozzl e concept s (fillpip e seals , nozzl e seals , an d combinatio n fillpipe/nozzl e seals ) show s that th e effectivenes s o f al l thre e concept s i s approximatel yequal . Durabilit yeffect s hav e no t bee n extensivel y evaluated , especiall yfo r th e nozzl e sea l concept . 5 . Avapor/liqui d pressur e relie f valv e i s require d t o protec t th e integrit yo f th e vehicl e fue l tan k durin g th e refuelin g process . Th e pressur e relie f valv e ca n b e designe d t o functio n o n th e fue l nozzle , o r i t ma yb e incorporate d a s par t o f th e fillpip e sea l mechanism , whic hwoul d b e sealed-of f b yth e fue l ca p durin g vehicl e operation . Durabilit yeffect s hav e no t bee n evaluate d fo r eithe r th e fillpip e o r nozzl e pressur e relief . ECT D recommend s tha t th e fillpipe/nozzl e sea l and pressur e relie f b e locate d o n th e vehicl e i f onboar d control s ar e required .P. 4
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6 . Th e consume r cos t fo r light-dut yvehicl e refuelin g los s contro l system s ar e estimate d t o b e $17/vehicle . Th e $1 7 estimat e doe s no t includ e cost s fo r a sea l o r pressur e relief . Cos t fo r a sea l and pressur e relief , i f use d o n th e vehicle , i s estimate d t o b e abou t $2.70 . Th e cos t o f a sea l o n th e nozzl e shoul d b e th e sam e a s th e cos t fo r a Stag e I I nozzle . Excep t fo r th e a s ye t undefine d durabilit yo f th e interfac e sea l n o maintenanc e cost s ar e expected . 7 . Th e feasibilit yo f controllin g refuelin g los s emission s fro m gasolin e fuele d truck s and diese l fuele d vehicle s ha s no t bee n evaluate d t o date . Technica l feasibilit yand cos t effectivenes s o f controllin g thes e source s shoul d b e determined . 8 . Mino r increase s i n C O exhaus t emission s ca n probabl yb e controlle d b

ymino r change s t o eithe r th e refuelin g los s contro l syste m o r t o th e exhaus t emissio n contro l system . Th e abilit yt o certif ya vehicl e t o a 3. 4 g/m i C O standar d t o 50,00 0 mile s shoul d no t b e seriousl yimpaired . 9 . Th e us e o f a bladde r i n th e fue l tan k appear s t o b e a viabl e alternativ e contro l strategy , bu t som e problem s exis t and technica l feasibilit yi s ye t t o b e demonstrated . 10 . Considerin g th e lead tim e neede d fo r regulatio n develop
men t an d revie wwithi n EP Aan d th e lea d tim e require d b yth e industr yfo r developmen t and applicatio n o f technology , implemen

tatio n o f onboar d control s canno t occu r befor e 1984 . ECT D recommend s tha t th e choic e betwee n onboar d contro l and Stag e I I contro l o f refuelin g los s emission s b e base d upo n ai r qualit yconsideration s and th e relativ e cos t effectivenes s o f th e tw o strategie s fo r th e sam e overal l leve l o f control . I t i s recommende d tha t method s o f reducin g th e cos t o f onboar d refuelin g contro l system s b e examine d b yconsiderin g tradeoff s betwee n contro l syste mcapacit yan d cost . I t ma yb e possibl e t o sacrific e som e capacit ytha t i s onl yrequire d unde r infrequen t condition s an d achiev e proportionatel ymor e significan t cos t savings . Th e feasibilit yan d desirabilit yo f contro l o f refuelin g losse s fro mligh t and heavy-dut ygasolin e fuele d truck s and fro m diese l fuele d vehicle s shoul d b e considered . EP Ashoul d suppor t th e developmen t o f th e bladde r tan k alternativ e fo r refuelin g los s contro l strategy . I f regulation s ar e t o b e develope d fo r onboar d refuelin g los s control , a certificatio n tes t procedur e must b e developed .P. 5
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III . Revie wo f Availabl e Informatio n Th e dat a an

dinformatio n summarize d i n thi s sectio n ar e base d o n materia l submitte d t o EP Abyth e America n Petroleu mInstitut e and informatio n receive d i n respons e t o a reques t fo r informatio n (43F R 27892 ) publishe d o n Jun e 27 , 1978 . Th e AP I material , Ref . 3 , i s th e resul t o f thei r mos t recen t studyt o asses s onboar d techni

ca l feasibilit yan d compar e th e cos t effectivenes s o f onboar d refuelin g control s and Stag e I I controls . Thi s studywa s initiate d a t th e urgin g o f EPA . Respondent s t o th e Federa l Registe r notic e include d Genera l Motors , Ford , an d AMC . Th e API , GM , and For d informatio n contai n dat a fro mtest s wit honboar d contro l hardware . Al l respondents , wit hth e exceptio n o f AMC , submitte d informatio n o n th e cos t an d th e desirabilit yo f onboar d contro l systems . 1 . AP I Onboar d Study Th e AP I Onboar d Contro l Stud ywa s structure d t o addres s question s regardin g onboar d feasibilit ywhic hwer e pose d t o AP I i n a Decembe r 197 7 meetin g wit hEPA . Th e AP I studyconsiste d o f thre e tasks : a vehicl e concep t demonstration , a fillpipe/nozzl e concep t demonstration , and a cost/benefi t analysis . Exxo n Researc hand Engineerin g Companyan d Mobi l Researc hand Developmen t Corpora tio n wer e th e AP I contractor s fo r th e vehicl e concep t demonstra
tion . Atlanti c Richfiel d Companywa s th e AP I contracto r fo r th e fillpipe / nozzl e concep t demonstration . Exxo n R & E complete d th e cost/benefi t analysi s fo r API . Th e vehicl e concep t modificatio n tas k ha d th e followin g desig n objectives : 1 ) Minimu m90 % overal l refuelin g vapo r recovery . 2 ) N o significan t effec t o n exhaus t emissions . 3 ) N o significan t effec t o n evaporativ e emissions . 4 ) Desig n shoul d b e durable , practical , an d safe . Th e fillpipe/nozzl e demonstratio n ha d th e followin g objec

tive s : 1 ) 90 % overal l vapo r control . 2 ) Compatibl e wit hexistin g vehicl e population . 3 ) Compatibl e wit hexistin g Stag e I I nozzles . 4 ) Desig n shoul d b e durable , practical , and safe . Tes t procedur e guideline s fo r th e AP I wor k wer e discusse d a t a meetin g wit hAP I o n Marc h15 , 1978 . Importan t procedura l guide

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- line s whic hresulte d fromtha t meetin g ar e summarize d a s follows : Fue l specification : Indolen e unleade d tes t fue l wa s use d fo r al l exhaust , evaporative , and refuelin g los s measurements . Dispense d fue l quantity : Tes t vehicle s wer e refuele d t o 100 % o f capacit yfro ma conditio n o f 10 % tan k capacity . Fue l tan k temperature/Dispense d fue l temperature : Th e dispen

se d fue l temperatur e wa s selecte d t o b e representativ e o f summe r refuelin g condition s i n Lo s Angele s durin g th e mont ho f August , o r abou t 85°F . Th e fue l temperatur e i n th e tan k wa s als o selecte d t o b e 85°F . Thus , th e refuelin g wa s isothermal. * Purg e Cycle : Fo r th e purpose s o f th e AP I study , th e onl y drivin g cycl e whic hwa s use d fo r purgin g th e refuelin g los s can iste r i s th e LA- 4 cycle . Individually , thes e tes t procedur e guideline s ar e considere d t o represen t rea l worl d situation s i n a hig hoxidan t formin g location , e.g. , Lo s Angele s durin g th e mont ho f August . Collec
tively , thes e guideline s impl ytha t th e AP I vehicle s demonstrate d th e feasibilit yo f onboar d contro l system s i n a n approximat e wors t cas e condition . Thi s reasonin g i s consisten t wit hearlie r EP A recommendation s tha t AP I er r o n th e conservativ e sid e durin g thei r study . Fo r example , Exxo n use d th e followin g tes t sequenc e t o quantif yth e exhaus t emission s interactio n betwee n th e refuelin g contro l syste mand th e exhaus t emissio n contro l system : 1 ) Loa d EC S (Evaporativ e Contro l System ) caniste r t o break
through . 2 ) Conditio n th e vehicl e b ydrivin g 2 LA-4's . 3 ) Soa k vehicl e overnight . 4 ) Loa d RC S (Refuelin g Contro l System ) caniste r t o break
through . 5 ) Conditio n th e vehicl e b ydrivin g 5 t o 6 simulate d cit y drivin g day s (4. 7 LA-4' s wit hon e hou r ho t soak s i n betwee n and a diurna l a t th e end o f th e day ) t o consum e 90 % o f th e fue l i n th e t ank . *Thi s represent s a conservativ e situatio n a s surve ydata , Ref . 4 , sho wtha t nationwid e dispense d fue l temperature s ar e typicall y lowe r tha n tan k fue l temperatures , therebyrepresentin g a vapo r shrinkag e situatio n durin g th e refuelin g process .P. 7
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- 6 ) Drai n th

e fue l tank . 7 ) Bloc k RC S caniste r line . 8 ) Fil l tan

k t o 40% , unbloc k RS C caniste r lines . 9 ) Conduc t diurna l evaporative tes t in SHED . 10 ) Drai n tan

k t o 10% . 11 ) Brin

g fue l tan

k liqui d an

d vapo r t o equilibriu mat 85° F (shake the vehicl e t o accelerat e the equilibriu mprocess) . 12 ) Refue l th e vehicl e t o 100 % i n SHE D wit h85' F fuel . 13 ) FT P 14 ) Ho t soa

k evaporative tes t i n SHED . Obviously , thes e tes t procedure s d o no t len d themselve s t o a routin e laborator

ycertificatio n tes t procedure . Theydo , however , permi t an approximatio n o f ho wa n onboard contro l syste mwoul d function in a sever e "real-world " situation . Areviewo f the thre e AP I contractor' s activitie s i s presented below . Exxo n Exxo n assume d th e responsibilt yfo r modifyin g fou r tes t vehicles . Thei r vehicle s included the following : 197 8 Chevrole t Capric e 197 8 For

d Pint o 197 8 Plymout hVolare * 197 8 Chevrole t Chevett e Al l vehicle s wer e designe d t o compl ywit h197 8 Californi a exhaus t an

d evaporativ e emissio n standard s (.4 1 HC , 9. 0 CO , 1. 5 NOx , 6. 0 Evap) .

* Vehicl e subsequentl ydroppe d fro mtes t progra

mbecaus e o f hig

h baselin e NOx levels .P. 8
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- Th e Capric e i s a conventiona l oxidatio n catalys t vehicle , whil e th e Pint o i s a three-wa ycatalys t vehicl e wit hfeedbac k carbureto r control . Vehicl e description s an d complet e refueling los s contro l syste mdescription s ar e presente d i n Tabl e A- l an d Figur e A- l o f the Appendix . The refueling los s canister s in the Caprice , Pint o an

d Chevett e ar e describe d a s follows : RC S Vehicl e Carbo n Volume Carbo n Mas s Carbon Type * Locatio n Capric e Pint o Chevett e 5.0 £

3.0 £ 3.0P _ 180 0 g

110 0 g 110 0 g BLP-F 3

BLP-F 3 BLP-F 3 Underhoo d

Underhoo d Trun k
* Sam e carbo n currentl yused for controlling evaporative emissions , The Exxo n exhaus t an d evporative emissio n tes t result s whic h compar e baselin e an d modifie d version s o f the Caprice , Pint o an d Chevett e ar e summarize d i n Table s 1 , 2 an d 3 . Engine-ou t dat a ar e summarized i n Table s 4 an d 5 . Refueling los s effectivenes s tes t result s ar e summarize d in Tabl e 6 . Al l Exxo n refueling emissio n test s assumed a no-lea k sea l a t th e fillpipe/nozzl e interface . I n laborator

ypractic e thi s wa s achieved wit hlea k fre e connection s fro mth e fue l nozzl e t o the fillpipe . Benzen e emission s fro mthe Capric e an

d Pint o wer e measure d during severa l o f the refueling los s SHE D tests . Thes e result s ar e summarize d i n Tabl e 7 . Th e Exxo n dat a indicat e tha t benzen e contro l i s directl yproportiona l t o refueling los s contro l effect
iveness , althoug

hcurren t benzen e level s in th e SHE D ar e a t the detectabl e limi t o f the instrumentation . Tabl e 8 present s Exxon' s manufacture r cos t estimate s fo r onboard contro l systems for the 197 8 Capric e an d Pinto . Thes e estimate s do no t includ e the cost s for fillpip e sealin g device s an

d pressur e reliefs . Thi s hardwar e represent s a n additiona l cos t o f approximatel y$1.5 0 (manufacturer' s cost ) per vehicle . Exxon' s cos t estimate s assum e an estimate d $.5 0 credi t for downsizing the EC S canister , whic hi n th e tw o caniste r system , control s onl y carbureto r losses . Exxo n estimate s the incrementa l cos t o f two caniste r refueling contro l systems t o rang e fro m$8.2 5 t o $10.53 . Thi s estimat e include s the above mentione d $.5 0 credi t bu t doe s no t include the $1.5 0 cos t for the fillpip e sea l an d pressur e relief . The corresponding cos t rang e for singl e caniste r refueling contro l systems i s $6.7 5 t o $9.00 . Fo r light-dutytrucks , Exxo n estimate s a cos t rang e o f $1 2 (larg e singl e canister ) t o $2 0 (tw o separat e refueling los s canister s or multistag e purg e systems) .Tabl e 1 FT P Exhaus t an

d Evaporativ e Emission s - Capric e Exhaus t (g/mi ) Evap . (g ) H C C O NOx Diurna l Ho t Soa k Tota l Baselin e Configuratio n
Modifie d Configuratio n n= 4 Ave . S.D . n= 4 Ave . S.D . 0.34 5

0.03 3 0.33 8 0.01 0 6.4 8

0.5 6 7.1 0 0.5 9 0.9 5

0.0 6 0.8 6 0.0 5 n= 3

n= 3 0 . 8

0 . 4 1. 1 0 . 3

n= 4 Ave . S.D . n= 4 Ave . S.D . 0.18 7

0.02 1 0.21 7 0.00 6 1.7 0

0.1 0 1.8 3 0.1 2 0.7 7

0.0 1 0.7 9 0.0 7 n= 3

n= 3 1. 0

0 . 2 0 . 9 0 . 3 2. 1 2. 9

0. 4 0. 8 2. 1 3. 1 0. 2 0. 4 Percen t Chang e - 2 +1 0 -1 0 + 7
Tabl e 2 FT P Exhaus t an

d Evaporativ e Emission s - Pint o Exhaus t (g/mi J

Evap . (g T H C C O NOx Diurna l Ho t Soa k Tota l Baselin e Configuratio n
Modifie d Configuratio n

Percen t Chang e +1 6 + 8 + 3 - 6 2. 5 0. 3 2. 4 0. 5 3. 5

0. 4 3. 3 0. 7 I

-J I

T J

C OTabl e3 FTPExhaus t

an dEvaporativ e Emission s - Chevett e
Exhaus t g/mi ) Evap . (g ) H C C

O NO x Diurna l Ho t Soa k Tota l Baselin e Configuratio n
Modifie d Configuratio n n= 3 Ave . S.D . n= 3 Ave . S.D . 0.2 7

0.0 2 0.2 6 0.0 5 3. 7

0.3 2 3. 6 0.2 8 1.0 9

0.0 4 1.1 3

— n= 4

0 . 8 0.3 6 0 . 3 0.0 8 2 . 6

0.7 9 1. 2 0.1 5 3 . 4

1.0 3 1. 5 0.1 5 I O O I

Percen t Chang e - 4 - 3 + 4 -5 6 *FT P+ 3 Ho t

Star t LA-4 s

oTabl e 4 Engine-Ou t Emission s - Capric e

Baselin e Configuratio n

Modifie d Configuratio n n= 5 Ave . S.D . n= 5 Ave . S.D . 1.2 8

0.0 5 1.2 9 0.0 9 26.4 2

0.7 2 32.0 4 2. 4 1.1 7

0.0 4 1.1 7 0.0 4 Percen t Chang e + 1 + 2 1 *FT P + 3 Ho t Star t LA-4 s Tabl e 5 Engine-Ou t Emission s - Pint o FT P (g/mi ) H C C O NO x Cit yDrivin g Day * (g ) H C C O NO x 41.8 6 2.0 0 42.3 2 1.9 0 733.8 6

39.2 7 853.5 2 61.5 1 38.6 8

1.1 7 41.3 4 3.1 7
+ 1 + 1 6 + 7

i v O I

FT P (g/mi ) H C C O NO x Baselin e Configuratio n

Modifie d Configuratio n n=4 Ave . S.D . n= 4 Ave . S.D . 1.8 3

0.0 6 1.7 7 0.0 9 52. 7

1. 2 60. 1 0. 8 1.2 5

0.0 8 1.1 2 0.0 4 Percen t Chang e - 3 + 1 4 -1 0Tabl e 6 Refuelin g Los s Measurement s

Potentia l H C (g ) SHE D H C (g ) Percen t Contro l Effectivenes s Capric e Ave . 93. 4 91. 0 89. 3 91. 2 0. 4 0. 4 0. 3 0. 4 9 9 Pint o

Ave , 51. 0 59. 3 53. 1 54. 5 1. 0 1. 3 1. 1 1. 1 o i

9 8 Chevett e

Ave , 62. 5 65. 5 60. 1 64. 6 63. 2 0. 5 1. 5 1. 1 1. 6 1. 2 9 8

T J tV 3Tabl e 7 Benzen e Emission s
Potentia l Benzen e Emissions*SHE D Measurement s (ppm)Measure d Loss*SHE D Measurement s (ppm ) Capric e Pint o 3. 0 2. 7

*A1 1 refuelin g at 85°F , RV P 9 lbs. , Benzen e conten t 0.7% . <0.0 5 <0.0 5P.1 4

1 $1 1 $ 0 5 0 .0 3 5 0 $ 3

2 0 1 0 3 0 0 5 0 7 2 -12
- Tabl e 8 COS T ESTIMATE S FOR ONBOAR D SYSTEM S Capric e Pint o (2 ) Charcoal^ '

$4.9 6

(3 ) Caniste r an

d Valve s 2.5 0

. . . (4 ) Tan k Modification s 0.5 0 Hose s an

d Tubing 1.5 7 Assembling an

d Installin

g @ $20.00/hr . 1.5 0 1.5 0 $8.7 5 Credi t fo

r Downsize d , . $0.5 0 $0.5 0 Evaporativ e Contro l Syste m$10.5 3 $8.2 5 (1 ) Estimate s ar e mad e for manufacturer' s large volum e production . (2 ) 180 0 g for th

e Capric e canister , 110 0 g for the Pint o caniste r a t $1.25/lb

m(Calgon BPL-F 3 carbon) . (3 ) Plasti c containe r an d valves . (4 ) Large r siz e float/roll-ove r valve . (5 ) 3/4 " vapo r line fro mfue l tan

k t o canister , 3/8 " purg e line . EPD M tubin g for vacuu

mcontro l lines . (6 ) Additiona l 4. 5 minute s labo r a t $20/hour . (7 ) Reduced siz e evaporative contro l canister .P.1 5

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- Exxo n estimate s th e averag e cos t fo r onboar d contro l system s t o b e $9/vehicle . Thi s i s base d o n th e followin g assumptions : 1 ) Onboar dsystem s ar e designe d t o contro l refuelin g emis

sion s fro mligh t dut yvehicle s wit ha haverag e fue l tan k siz e o f 1 7 gallon s refuele d t o 100 % capacit yfro ma conditio n o f 10 % tan k capacity . Th e onboar d system s ar e designe d t o contro l hydrocarbo n emission s a t a leve l o f 6 g/gal . 2 ) 70 % o f light-dut yvehicle s and singl e tan k light-dut y truck s ar e assume d t o us e singl e caniste r (eva p + refueling ) systems . 3 ) 30 % o f light-dut yvehicle s and singl e tan k light-dut y truck s ar e assume d t o us e tw o caniste r systems . 4 ) Ligh t dut ytruck s wit hdua l o r larg e fue l tank s consti

tut e approximatel y10 % o f th e light-dut yvehicl e and light-dut y truc k population . I n summary , Exxo n find s tha t onboar d refuelin g control s fo r light-dut yvehicle s ar e a technicall yfeasible , practical , and cos t effectiv e alternativ e t o Stag e I I vapo r recovery . The yar e o f th e opinio n tha t th e sam e ma yals o b e sai d fo r light-dut ytrucks . Mobi l Mobi l R& D ha s modifie d a 197 8 Pontia c Sunbir d fo r contro l o f refuelin g losses . Thi s vehicl e ha s a three-wa ycatalys t wit ha feedbac k carbureto r contro l system , an d i s certifie d fo r complainc e wit hCaliforni a exhaus t an d evaporativ e emissio n standards . Thi s modifie d vehicl e use s a singl e caniste r whic hcontain s 155 0 gram s o f Calgo n BLP-F 3 carbon . Th e complet e vehicl e and refuelin g los s contro l syste mdescription s ar e presente d i n th e Appendix . Tabl e 9 present s comparison s o f exhaus t and evaporativ e emission s fro m th e Sunbir d fo r th e baselin e and modifie d configurations ; a summar yo f th e refuelin g emissio n dat a i s presente d i n Tabl e 10 . Simila r t o Exxon' s findings , Mobi l state s tha t thei r tes t result s hav e demonstrate d tha t onboar d control s ar e a feasibl e an d desirabl e metho d o f controllin g refuelin g losse s fro mlight-dut y vehicle s and light-dut ytrucks . Atlanti c Richfiel d Company On e o f th e requirement s fo r th e operatio n o f a n effectiv e refuelin g los s contro l syste mi s a no-lea k sea l a t th e fillpip e nozzl e interface . Atlanti c Richfiel d (ARCO ) ha s designe d an d teste d thre e type s o f sealin g systems . The yincluded : 1 ) Modificatio n o f th e vehicl e fillpip e t o achiev e a sea l whe n use d wit hconventiona l lead-fre e nozzles .Tabl e 9 FT P Exhaus t an

d Evaporativ e Emissio n Comparison s —Sunbir d Exhaus t (g/mi ) H C C O NOx Diurna l Evap . (g ) Ho t Soa k Tota l Baselin e Configuratio n
Modifie d Configuratio n n= 9 Ave . S.D . n= 6 Ave . S.D . 0.3 9

0.0 3 0.4 0 0.0 3 6.4 1

0.9 1 6.3 5 0.7 4 0.9 8

0.0 7 0.9 9 0.0 3 n= 2

n=4 0.8 7

03 0 0.7 2 0.2 3 1.1 2

0.1 3 1.2 7 0.3 7 2.00 *

0.3 4 2.1 1 0.5 6 Percen t Chang e + 3

- 1 + 1 + 6

* Include s fiv e test s a t lo wmileag e wher e individua l diurna l an d ho t soa k result s ar e no t available . •p i

Tabl e 1 0 Refueling Los s Measurement s —Sunbird

Fue l Dispense d (gal ) H C Collecte d i n Caniste r (g) * Refuelin g Emission s SHE D Measurement s (g/gal ) Contro l Efficienc y(% ) 16. 4 15. 3 16. 9 17. 1 8 5 7 3 11 3 10 9 0.1 8 0.0 2 0.4 4 0.3 6
* Caniste r purge d fro ma nomina l workin g capacit yloa d o f 21 0 g . Fue l o f nomina l 9 lbs . RVP . 8 gp mrefuelin g rate , using modifie d Stag e I I nozzle . 9 7 9 9 9 4 9 5P.1 7
-15
- 2 ) Modification s t o bot hth e fillpip e and lead-fre e nozzle . 3 ) Modificatio n o f a Stag e I I vapo r recover ynozzle . Adescriptio n o f eac htyp e o f sea l an d a summar yo f th e durabilit ydat a collecte d wit heac hsyste mar e presente d below : Fillpip e seals : Tw o type s o f fillpip e seal s hav e bee n ex amined . The yar e a rotar ygreas e sea l (simila r t o greas e seal s use d o n rotatin g machiner yshafts) , and a doughnu t shape d seal . Th e materia l type s fo r thes e tw o seal s ar e a compounde d nitril e and thermosettin g urethane , respectively . Mor e complet e description s o f thes e seals , includin g durabilit ydata , ar e found i n Figur e A- 5 and Table s A- 2 an d A- 3 o f th e Appendix . Appproximatel ythirt y day s o f durabilit ytest s wit hbot htype s o f seal s hav e demonstrate d tha t th e rotar ysea l i s mor e effective , basicall ydu e t o th e absenc e o f expansio n problem s whe n expose d t o gasolin e liqui d and vapo r atmospheres . Th e sea l effectivenes s o f th e prototyp e fill

pip e and nozzl e hardwar e ar e determine d b ya benc htes t apparatu s whic hpressurize s a particula r syste mand measure s th e resultin g lea k rates . Sea l effectivenes s calculation s ar e determine d b y dividin g th e lea k rat e bya nomina l fuelin g rat e (assume d t o b e 7. 5 gallons/min.) . Durabilit ytest s conducte d wit hth e rotar ysea l hav e demonstrate d tha t th e rotar ysea l i s effectiv e afte r 700-100 0 nozzl e insertions , whic hcorrespon d t o th e numbe r o f fue l fill s expecte d durin g th e lif e o f th e vehicle . Combinatio n fillpipe/nozzl e seals : Thes e system s consis t o f connectin g part s o n bot hth e fillpip e and nozzle . Figur e A- 6 i s a n exampl e o f a prototyp e desig n evaluate d byARCO . Durabilit ytes t result s wit hthes e system s ar e simila r t o result s obtaine d wit hth e rotar yseal . Nozzl e Modification : Workin g prototype s o f vapo r recover y nozzles , modifie d fo r refuelin g los s control , hav e bee n develope d b yOP W an

d Emc o Wheato n and evaluate d byARC O fo r effectivenes s and durability . Thes e nozzle s ar e designe d t o sea l o n standardize d fillpipes . Th e modifie d vapo r recover ynozzle s incorporat e a pressur e relie f valve , whic hi s locate d a t th e vapo r retur n exi t o r cas t int o th e nozzl e bodyand designe d t o ope n a t approximatel y 14-1 7 in . wate r pressure* , therebypermittin g th e nozzl e t o refue l onboar d contro l vehicle s and in-us e vehicles . Nozzl e durabilit y dat a ar e ver ylimite d bu t on e nozzl e ha s bee n inserte d and latche d 750 0 times , representatitv e o f on e yea r o f servic e a t a hig hvolum e station , an d showe d a sea l effectivenes s o f greate r tha n 99% . ARC O conclude s tha t th e preferre d sea l technique s ar e eithe r th e fillpip e sea l metho d o r th e combinatio n fillpipe/nozzl e seal . * Refuelin g los s contro l system s designe d b yExxo n and Mobi l ar e designe d t o operat e a t fil l pressure s o f les s tha n 4 in . o f wate r pressure .P.1 8 

### -16
- 2 . Vehicl e Manufacture r Informatio n Genera l Motor s Genera l Motor s ha s severa l reservation s concerning the appli

cabilit yo f onboard controls , citing suchthing s as : the uncer taintyo f the effectivenes s o f fillpipe/nozzl e seals , potentia l cos t increase s associate d wit hexhaus t emissio n contro l systems whic hmus t be designe d t o contro l increased CO emissions , negative fue l penaltie s whic har e th e resul t o f thi s increased emissio n control , an

d th e long lea d tim e whic hi s require d t o obtai n a substantia l reductio n i n atmospheri c hydrocarbo n an d benzen e loading . G

M ha s stated tha t refueling losse s can be controlle d o n th e vehicl e (feasibilit yfor truck s ha s no t bee n demonstrated ) or a t th e servic e station . GM' s disagreement s wit hcontrollin g refuelin g emission s wit honboar d control s ar e primaril ybase d o n th e issue o f cost/effectiveness . Mor e recently , (Ref . 1 3 & 14) , G M ha s expresse d concern abou t possibl e inadequacie s i n th e desig n o f th e AP I demonstratio n vehicles . Specifically , G M state s tha t a larg e diamete r refueling ven t an d a smal l restricte d ven t ar e necessar yfor protectio n fro m overfilling the fue l tan k an d preventing excessive hydrocarbo n loadin g o f the storag e caniste r during hig htemperatur e vehicl e operation . GM' s March , 197 8 submission t o EP Apresent s a summar yo f thei r wor k on the contro l o f diurna l evaporativ e emission s an d refueling losse s using fue l tan k bladders . I t i s EPA' s opinio n tha t the theoretica l contro l effectivenes s o f evaporative an

d refueling los s emission s usin g bladde r tan

k technolog

yi s hig

han d tha t problem s related t o vapo r storage , pressur e relie f valves , an d bladde r material s can be solved . I t i s recommende d tha t bladde r tan k feasibilit yb e researche d b y fundin g a bladde r tan

k hardwar e demonstratio n contract . The March , 197 8 submissio n present s calculation s showin g tha t th e additiona l weigh t o f th e component s o f an onboar d contro l syste mwil l cance l ou t an ypotentia l energ

ysavin

g whichresult s fro mthe combustio n o f the refueling vapors . ECTD agree s wit h thi s analysis . The June , 197 8 submissio n i s basicall ya cos t effectivenes s analysi s comparing onboard control s wit hStag e I I control s (balanc e displacemen t an

d vacuu massis t systems) . G M estimate s tha t onboard contro l systems , effective wit hthe 198 2 mode l year , wil l rang e fro m$1 6 t o $24 . Thes e figure s ar e abou t $ 5 t o $ 9 highe r than the March , 197 8 estimate s du e t o highe r estimate s for large r canister s an d a newvapor/liqui d separator . G M assume s tha t the sea l a t the fillpipe/nozzl e interfac e wil l be obtaine d usin g modifie d vapo rP.1 9

-17
- covery . Rather , G M emphasize s certai n technica l concern s whic h theysa yar e no t full yaddressed b ythe AP I study . According t o GM , thes e include API' s unsubstantiate d suppor t for the onboard fillpip e sea l an

d pressur e relie f (lac k o f adequat e durabilit y results) , a

nunknow

nC O penaltyfor light-dutyvehicle s (n o sensi

tivitydat a relatin g C O t o tes t procedur e differences) , an d un prove n feasibilityfor trucks . G M i s o f the opinio n tha t accelerate d laborator ydurabilit y test s ar e no t sufficien t t o prove tha t proposed elastome r typ e seal s wil l b e effective in the extreme usag e an d environmenta l condition s o f the rea l world , particularl ywhe n considering a ten yea r averag e lifetim e for a light-dutyvehicle . Ford Ford ha s submitted tes t result s fro mfou r 197 8 mode l yea r vehicle s (thre e non-feedbac k system s an d on e feedbac k contro l system ) modifie d for refueling los s control . Thes e vehicle s ar e describe d i n detai l i n Tabl e A- 4 i n th e Appendi x an d i n thei r submissio n t o EPA , Ref . 7 . The purg e contro l systems for thes e vehicle s ar e show

n i n Figure s A- 7 an d A- 8 in the Appendix . For d estimate s the cos t t o the consume r o f onboar d control s t o rang e fro

m$15-$20 . Theynot e tha t the $15-$2 0 estimat e doe s no t include additiona l expens e for suchitems as : packaging costs , incrementa l labo r costs , o r th e cost s fo r additiona l exhaus t emissio n control , suc ha s feedbac k contro l ove r a wide r air/fue l rati o range . Recen t For d material , Ref . 12 , sugges t tha t th e cos t o f onboar d system s ma yrang e from$3 0 t o $253 . Th e $3 0 estimat e include s cost s ove r the origina l $15-2 0 estimate , includin g cost s for suchitems a s vehicl e modification s t o packag e onboard systems , incrementa l assembly , an d materia l substitution . Th e $25 3 estimat e include s the cos t for a feedbac k fue l syste man d electroni c con trol s for vehicle s whic har e no t planned t o be equippe d wit hthes e contro l devices . O n the basi s o f thei r in-hous e tes t results , For d ha s conclu
ded tha t onboard control s ar e no t technicall yfeasibl e for light

dut yvehicles . American Motor s AMC ha s submitte d a lette r t o EPA , Ref . 9 , whic hstate s thei r concern s wit hthe possibl e us e o f onboard controls . Theystat e tha t packagin g concerns , reduce d quantitie s o f purg e ai r fro m downsize d engines , an d complianc e wit hstringen t evaporativ e emissio n standard s ar e unresolve d technica l issue s whic hhav e no t bee n addresse d b

ythe AP I work t o date .P.2 0 

### -18
- AM C doe s no t fin

d tha t AP I ha s demonstrate d light-dutyvehicl e technica l feasibility . IV . Analysi s o f Availabl e Informatio n 1 . AP I Wor

k Exxo n Exxo n R& E appear s t o hav e don e a credibl e jo b in character
izin g th e component s o f a hydrocarbo n adsorptio n system . An examinatio n o f the result s fro mbaselin e test s an d test s wit hthe modifie d Pint o (3-wa y+ feedbac k carbureto r system ) sho wsmal l bu t finit e increase s in engine-ou t (14% ) an d tailpip e (8% ) C O emis

sions . HC , CO , an d NO x emission s ar e stil l wel l belowstatuator y emissio n level s for lo wmileag e vehicles . Engine-ou t C O emission s fro mthe Capric e ar e approximatel y20 % highe r than baselin e tes t results ; tailpip e C O emission s ar e approximatel y10 % highe r tha n the baselin e results . N o increas e i n tailpip e C O wa s observed during test s wit hthe Chevette . Exxo n suggest s tha t difference s in CO emission s for the Capric e an d the Pint o can b e furthe r reduced b ymino r modification s t o the refueling los s contro l syste mo r th e exhaus t emissio n contro l system , althoug hthi s ha s no t bee n demon
strated . Figur e A- 2 show s caniste r purg e a s a functio n o f time . Althoug hthe dat a ar e benc htes t results , the result s ar e als o representative o f actua l contro l syste mpurg e data . I t i s signifi

can t t o not e tha t the refueling los s caniste r i s essentiall ypurged t o it s workin g capacit yafte r thre e LA- 4 drivin g days . Thi s implie s tha t th

e refueling control/exhaus t emissio n interaction i s likel yt o be les s in a typica l driving da ytha n Exxo n ha s measure d usin g conservative tes t methods , whic hrequired runnin g a col d star t FTP immediatel yafte r a 90 % refueling . ECTD expect s tha t refueling los s contro l systems wil l resul t in slightl yhighe r C O feedga s levels . Exxo n estimate s tha t the averag e increase s in C O feedga s betwee n refueling s wil l b e approx imatel y5 % for non-feedbac k contro l systems an d les s tha

n 3 % for feedbac k contro l systems . ECTD ha s n o othe r dat a concerning eithe r the magnitud e o f the averag e C O feedga s penaltyo r the resulting effec t o

ncatalys t durability . I t i s ECTD' s opinio n tha t the Exxo n estimate s ar e reasonabl e an d tha t thes e additiona l C O penaltie s wil l make i

t more difficul t for vehicl e manufacturer' s t o certif y som e engine/familie s t o the 3. 4 g/mi C O standard . The highe r C O level s somewha t reduc e th e margi n availabl e t o allowfor exhaus t syste mdeterioratio n ove r 50,00 0 miles . ECTD find s tha t light-dutyvehicle s equippe d wit honboard system s ar e capabl e o f meetin g a 2 gra mevaporativ e emissio n standard .P.2 1

-19
- An analysi s o f th e contro l effectivenes s o f benzen e emission s durin g refueling , Tabl e 6 , indicate s tha t charcoa l canister s ca n contro l i n exces s o f 99 % o f th e uncontrolle d benzen e emissions . Exxo n conducte d additiona l test s wit hth e Capric e an d Pint o usin g indolen e tes t fue l wit ha hig hbenzen e conten t (4.2%) . Th e result s fro mthes e fiv e test s sugges t tha t benzen e emission s ar e controlle d i n exces s o f 99 % durin g refueling . Packagin g refuelin g los s contro l system s i s a difficul t problem , bu t definitel yno t a n insurmontabl e one . Th e refuelin g los s caniste r i s locate d behin d th e rea r sea t and abov e th e rea r axl e i n th e Caprice , and i n th e engin e compartmen t o f th e Pinto . I t i s Exxon' s opinion , an d ECT D agrees , that ' i t i s possibl e fo r manufacturer s t o locat e a refuelin g los s caniste r o n downsize d vehicle s withou t majo r engin e compartmen t o r sheetmeta l modifica

tion s . Th e feasibilit yo f refuelin g los s control s fo r light-dut y truck s ha s no t bee n evaluate d b yExxon , bu t the yar e o f th e opinio n tha t refuelin g los s contro l i s feasibl e fo r light-dut ytruck s by usin g large r contro l system s an d mor e sophisticate d purgin g con trol s (refuelin g los s contro l canister s fo r eac htan k and/o r tw o stag e purgin g systems) . I t i s ECTD' s opinio n tha t th e contro l o f refuelin g losse s fro mlight-dut ytruck s need s t o b e demonstrated , especiall yth e abilit yt o compl ywit ha 2 g eva p standard , befor e onboar d control s ar e judge d t o b e effectiv e fo r thes e vehicle s a t th e cost s Exxo n ha s estimated . Tabl e 8 show s Exxon' s detaile d manufacturer' s cos t estimate s fo r refuelin g contro l system s whic hhav e tw o canisters . ECT D find s thes e cos t estimate s t o b e reasonabl e fo r onboar d system s designe d t o contro l 100 % o f refuelin g emission s fro m90 % fil l conditions . Exxo n estimate s th e averag e manufacturer' s cos t fo r th e light-dut y truc k an d light-dut yvehicl e populatio n t o b e abou t $9 . Tha t numbe r i s derive d a s follows :

One-cansite r vehicles * Two-caniste r vehicles * 6,00 0 t o 8,500 . lbs . trucks* *

Weighte d averag e $9.0 0 A s sum e Averag e $7.8 8 $9.3 8 $16.0 0 d

Cos t P c % o f

>pulatio n 7 0 2 0 1 0

* Include s light-dut yvehicle s and light-dut ytruck s unde r 600 0 GVW - averag e fue l tan k siz e = 1 7 gal . * * Averag e fue l tan k siz e = 3 5 gal . Th e charcoa l cos t pe r gallo n o f tan k volum e i s assume d t o b e abou t $0.20 .P.22 ^

-20
- T he $ 9 incrementa l manufacture r cos t ma yb e translate d t o a consume r cos t estimat e o f $16.2 0 b ymultiplyin g th e manufacturer' s cos t estimat e bya facto r o f 1. 8 (Ref . 10 , EP ARepor t "Cos t Esti

mation s fo r Emissio n Contro l Relate d Components/System s and Cos t Methodolog yDescription " b yRat han

d Strong , Marc h1978) . Th e 1. 8 facto r i s i n genera l agreemen t wit hpreviou s EP Astudies , suc ha s th e EP AReport , Ref . 11 , "Investigatio n and Assessmen t o f Light

Dut yVehicl e Evaporativ e Emissio n Source s and Control, " Jun e 1976 , whic huse d a manufacture r t o consume r cos t facto r o f 2.0 . Th e $16.2 0 estimat e i s i n goo d agreemen t wit hconsume r cos t estimate s submitte d byG M ($16-$24 ) and For d ($15-$20) . I t i s possibl e t o furthe r reduc e th e cos t o f a n onboar d syste mb ytradin g of f som e degre e o f refuelin g los s contro l effectiveness . Exxo n ha s designe d refuelin g los s contro l system s base d o n conservativ e criteria , and thu s a differen t se t o f desig n criteri a wil l affor d reduction s i n th e cos t o f onboar d contro l systems . Texac o ha s submitte d dat a (Figur e A-ll ) Ref . 12 , whic hrelate s th e numbe r o f light-dut yvehicl e refueling s and th e percen t o f tan k fill . Areasonabl e desig n criterio n i s t o siz e th e refuelin g canister s t o contro l 90 % o f nationwid e refuelin g emissions . Calculation s (Figur e A-12 ) sho wtha t 90 % contro l ca n b e achieve d b y designin g system s t o contro l 100 % o f refuelin g emission s fro mfill s t o 63 % o f fue l tan k volume . I f onboar d contro l system s ar e de
signe d t o contro l emission s fro mrefuelin g t o 63 % o f tan k capacit y rathe r tha n 90 % o f tan k capacity , th e Exxo n estimat e o f $ 9 pe r vehicl e ca n b e reduce d by$1.6 0 a s th e resul t o f reduce d charcoa l quantity . Thi s cos t reductio n i s proportiona l t o th e reductio n i n carbo n be d volume . Th e ne t effec t o f thi s desig n chang e i s a cos t reductio n t o th e consume r o f approximatel y$2.88 . Change s i n desig n specification s suc ha s th e 90 % fil l requiremen t ma yaffor d additiona l cos t reduction s fo r othe r contro l syste mcomponent s a s wel l a s a genera l reductio n i n th e proble mo f packagin g onboar d contro l systems . ECT D estimate s th e consume r cos t o f light-dut yvehicl e onboar d contro l system s designe d fo r maximu mcontro l effectivenes s t o b e abou t $17 . Thi s estimat e doe s no t includ e a n estimat e fo r th e cos t o f th e fillpip e sea l o r pressur e relie f valve . Th e $1 7 estimat e i s base d o n Exxo n estimates , whic hwhe n translate d t o consume r costs , ar e i n agreemen t wit hconsume r cos t estimate s provide d b yGM and Ford . Exxo n estimate s th e manufacturer' s cos t fo r a fillpip e sea l and onboar d pressur e relie f valv e t o b e approximatel y$1.50 . ECT D estimate s th e consume r cos t o f a n onboar d fillpip e sea l and pres sur e relie f t o b e $2.70 . Mobi l Comparison s o f baselin e and modifie d vehicl e tes t result s indicat e tha t Mobi l R& D i s abl e t o add refuelin g control s t o th eP.2 3

-21
- 197 8 Pontia c Sunbird (3-wa y+ feedbac k carbureto r system ) withou t adversel yaffectin

g exhaus t o r evaporative emissions . No change s in engine-ou t or tailpip e C O emission s ar e observed . Evaporative emission s ar e als o unchanged , wit hbot hbaselin e an d modifie d vehicl e tes t result s nea r th e 2 g evaportiv e emissio n level . I t mus t b e emphasized , however , tha t Mobi l an d Exxo n us e differen t tes t procedure s for measuring the refuelin g control / exhaus t emissio n interaction . Mobil' s tes t procedur e consist s o f th e followin

g sequenc e o f events : 1 ) Loa d caniste r t o approximatel yone-hal f o f workin g capacity . 2 ) Conditio n vehicl e b ydriving two simulated citydriving day s (4. 7 LA-4' s wit hone hou r ho t soak s in betwee n an d a diurna l at the en

d o f the day) . 3 ) Drai n fue l tan k t o 10 % o f volume . 4 ) Refue l t o 90 % o f volume in SHED . 5 ) Conduc t ho t star t emissio n test . 6 ) Soak vehicl e for 1 1 hrs . 7 ) Conduc t diurna l evaporativ e tes t i n SHED . 8 ) FTP 9 ) Ho t soa

k evaporative tes t i n SHED . Step s 1 , 2 , an

d 5 ar e the importan t difference s betwee n the tes t procedure s used b yExxo n an

d Mobil . Mobi l start s thei r tes t sequenc e wit ha caniste r loaded t o one-hal f o f working capacity , versu s a saturated conditio n for the Exxo n procedure . Mobi l purge s the refueling los s caniste r wit htw o LA- 4 driving days , versu s the Exxo n metho d o f purgin g b yrunning a serie s o f LA- 4 driving day s unti l the fue l tan k reache s 10 % o f capacity . Mobi l run s a ho t star t emissio n tes t prio r t o th e FTP ; n o suc

hadditiona l condition

in g i s used in the Exxo n tes t sequence . I t i s ECTD' s opinio n tha t the the Mobi l tes t sequence , particularl ythe additio n o f a ho t star t exhaus t emissio n test , wil l resul t in a les s sever e refueling control/exhaus t emissio n interaction . Thi s i s du e t o the smalle r quantit yo f hydrocarbo n whic hi s purged during the col d star t FTP whe n using the Mobi l tes t sequence . The actua l emissio n sensi

tivityt o variou s tes t procedur e arrangement s ha s no t ye t bee n determined . Atlanti c Richfiel d Compan y ARC O state s tha t th e fillpip e modificatio n approachan d th e-22
-

combinatio n fillpipe/nozzl e sea l concep t ar e the preferred tech
nique s for achieving a no-leak seal . Thi s recommendatio n i s no t supported fro

ma n analysi s o f lea

k rat e an

d durabilit ydat a becaus e th e tes t result s sho wtha t sea l effectivenes s amon g al l thre e concept s ar e equal . Cos t estimate s for the thre e design s hav e no t bee n submitted . ARC O i s continuing t o collec t fiel d durabilit y dat a o n thei r prototypes , bu t th e lac k o f a mor e extensive durabil

it ydemonstratio n unde r simulated condition s o f rea l worl d usag e make s i t questionabl e t o assum e tha t thei r seal s wil l function a s wel l in th

e fiel d a s the

yhav e in the laboratory . I n particular , ARC O ha s no t adequatel yaddressed the issue o f onboard pressur e relie f valve s versu s liqui d pressur e relie f valve s located on the fil l nozzle . Pressur e relie f valve s ar e necessar y t o preven t over-pressurizatio n o f th e fue l tan

k in the even t o f a failur e o f th e automati c shutof f o n th e fil l nozzle . Fo r th e purpos e o f fue l tan k integrityin the even t o f a vehicl e crash , NHTSArecommend s tha t the pressur e relie f no t b e located o n the fue l tank . However , a relie f valv e migh t b e incorporate d safel y wit ha fillpip e sea l mechanism , whic hwoul d b e sealed-of f b ythe fue l ca p during vehicl e operation . Th e achievemen t o f a saf e an d durabl e sea l a t th e nozzl e fillpip e interfac e i s critica l t o the performanc e o f a n onboard refueling los s contro l system . ARC O ha s demonstrate d tha t the effectivenes s o f fillpip e seals , combinatio n seal s an d nozzl e seal s ar e equal ; but the design , location , an d durabilit yo f the pressur e relie f valve hav e no t bee n adequatel yaddressed . Conceptually , a pressur e relie f maybe designe d t o function properl ywhe n located o n th e vehicl e o r on the nozzle . However , i f refueling losse s ar e controlle d on the vehicle , i t i s recommende d tha t the fillpipe/nozzl e sea l an d pressur e relie f valv e als o b e located on th

e vehicle . Locating al l part s o f a n onboard syste

mo n the vehicl e wil l preven t the potentiall yseriou s proble mo f refuel
in g a controlle d vehicl e withou t protectio n fro moverpressurizatio n (n o relie f valve) . Administrativ e an d certificatio n concern s als o sugges t tha t onboard control s ar e practica l onl yi f the sea l an d pressur e relie f ar e located .onboard . A n alternative techniqu e o f achieving a sea l at th e fillpipe / nozzl e interfac e i s the liqui d tra p o r submerged fill . Thi s sea l concep t ha s no t bee n adequatel yinvestigated . Submerge d fil l offer s the potentia l for significan t advantage s i n terms o f simpli

cityo f operatio n an d durabilit y(mechanical , magnetic , or elas
tome r typ e seal s ar e avoided) . I t i s ECTD ' s opinio n tha t th e submerged fil l concep t shoul d be investigated . Submerge d fil l (an d sea l technique s investigate d b yARCO ) mus t be evaluate d in the contex t o f a complet e refueling an d evaporative emissio n contro l system . Thi s include s incorporatin g feature s t o provid e adequat e therma l expansio n capabilit yan d rollove r protectio n whil e stil l permitting norma l saf e refueling .-23
-

2 . Vehicl e Manufacture r Informatio n Genera l Motor s Genera l Motor s ha s severa l reservation s concerning the appli

cabilit yo f onboard controls , citin g suchthing s as : the uncer taintyo f the effectivenes s o f fillpipe/nozzl e seals , potentia l cos t increase s associate d wit hexhaus t emissio n contro l systems whic hmus t b e designe d t o contro l increased C O emissions , negative fue l penaltie s whic har e th e resul t o f thi s increased emissio n control , and th e lon g lea d tim e whic hi s require d t o obtai n a substantia l reductio n i n atmospheri c hydrocarbo n an d benzen e loading . G

M ha s state d tha t refueling losse s can b e controlle d o n th e vehicl e (feasibilityfo r truck s ha s no t bee n demonstrated ) o r a t th e servic e station . GM' s disagreement s wit hcontrollin g refueling emission s wit honboard control s ar e primaril ybase d on the issue o f cost/effectiveness . Mor e recently , (Ref . 1 3 & 14) , G M ha s expresse d concern abou t possibl e inadequacie s i n th e desig n o f th e AP I demonstratio n vehicles . Specifically , G M state s tha t a larg e diamete r refueling ven t an d a smal l restricte d ven t ar e necessaryfo r protectio n fro m overfilling the fue l tan k an d preventing excessive hydrocarbo n loadin g o f th

e storag e caniste r durin g hig htemperatur e vehicl e operation . GM' s March , 197 8 submissio n t o EP Apresent s a summar yo f thei r wor k o n the contro l o f diurna l evaporative emission s an d refueling losse s using fue l tan k bladders . I t i s EPA' s opinio n tha t th e theoretica l contro l effectivenes s o f evaporative an

d refueling los s emission s usin g bladde r tan

k technolog

yi s hig

han d tha t problems relate d t o vapo r storage , pressur e relie f valves , an d bladde r material s ca n be solved . I t i s recommende d tha t bladde r tan k feasibilit yb e researche d b y fundin g a bladde r tan

k hardwar e demonstratio n contract . Th e March , 197 8 submissio n present s calculation s showing tha t th e additiona l weigh t o f th e component s o f a n onboar d contro l systemwil l cance l ou t an ypotentia l energ

ysavin

g whic hresult s fro mthe combustio n o f the refueling vapors . ECTD agree s wit h thi s analysis . Th e June , 197 8 submissio n i s basicall ya cos t effectivenes s analysi s comparing onboard control s wit hStag e I I control s (balanc e displacemen t an

d vacuu massis t systems) . G M estimate s tha t onboard contro l systems , effective wit hth e 198 2 mode l year , wil l rang e fro m$1 6 t o $24 . Thes e figure s ar e abou t $ 5 t o $ 9 highe r tha n th e March , 197 8 estimate s du e t o highe r estimate s for large r canister s an d a newvapor/liqui d separator . G M assume s tha t th

e sea l at the fillpipe/nozzl e interfac e wil l be obtained usin g modifie d vapo rP.2 6 -24 -

recover y nozzles . G M doe s no t

includ e sea l cost s i nit s estimate . They assum e thes e cost s wil l b e th e sam e fo r eithe r Stag e I Io r onboar dcontrol s an dhence , leav e thes e cost s ou t of thei r analy

si s o f bot hoptions . Genera l Motor' s onboar dcos t estimate s ar e cost s t o th e consumer . Thes e estimate s ar e base do ncost s fo r hydrocarbo nadsorptio nsystem s whic hcontro l evaporativ e an d refuelin g emission s wit hon e caniste r an dsystem s whic hus e two separat e canister s fo r containin g evaporativ e (diurna l an dho t soak ) an drefuelin g emissions . The G M cos t estimate s ar e con sisten t wit hExxon' s manufacturer s cos t estimate s fo r

onboar d controls . A

s discusse dearlier , i t i s possibl e t o desig ncheape r refuelin g los s contro l system s b y no t providin g 100

% contro l o f refuelin g emission s unde r wors t cas e conditions . I f th e desig n criterio no f

100% contro l fo r a90 % refuelin g i s change dt o 100 % contro l fo r

a63 % refueling , i t i s possibl e t o reduc e th e require dworkin g capacit y o f th e charcoa l canister , thu s reducin g th e averag e syste mcos t t o th e consume r

by abou t

$3.00 . G M di dno t

commen

t o nth e feasiblit y o f refuelin g los s con trol s fo r

light-dut y truck s an dheavy-dut y gasolin e powere dve hicles . For d Ford emphasize s tha t th e refueling loss/exhaus t emission s interactio n i s a functio n o f th e tes t procedur e an d tha t th e difference s betwee n emission s interaction s measure d b yExxo n an

d Mobi l ar e du e t o tes t procedur e differences . Thi s statemen t i s correct , althoug hth e actua l emissio n sensitivit yt o th e tes t procedur e i s unknown . Ford attribute s th e hig hC O effect s whic hthe yhave observe d wit hbot hconventiona l oxidatio n catalys t systems an d three-wa

y plu s feedbac k carbureto r system s t o the presenc e o f refueling los s controls . However , hig hC O emission s ar e likelythe resul t o f using a manifol d vacuu mpurg e contro l system . Thi s syste mresult s i n cold-star t hydrocarbo n loading s tha t ar e tw o t o thre e time s highe r tha

n result s obtaine d wit hventur i vacuu mcontro l systems (Exxon system) . Thi s i s the reaso n the Ford result s ar e s o high , particularl yengine-ou t C O emissions . Ford maintain s tha t refuel
in g los s contro l systems produc e peak enrichmen t effect s equa l t o tw o air/fue l ratios , whic hi s beyon d th e capabilit yo f thei r curren t feedbac k carbureto r contro l system . Exxo n ha s demon
strated , however , tha t ventur i vacuu

mmaintain s th

e air/fue l rati o withi n th

e contro l limit s o f the feedbac k contro l system . Problem s wit hthe existing Ford feedbac k contro l systemar e likelyt o b e the resul t o f respons e tim e problems , no t contro l rang e problems . Som e o f Ford' s concern s wit honboard refueling contro l sys tems , sucha s packaging , weigh t o f onboard systems , an d the design o f vapor/liqui d separator s hav e bee n examine d durin g the AP I stud

yP.2 7 -25 -
andshow

nno t t o b e significan t

proble mareas . Othe r concern s wit h onboar dcontrols , includin g syste mdurability , onboar dfeasiblit y fo r ligh t andheav y dut y trucks , andhig haltitud e feasibility , hav e no t

bee nadequatel y addresse di nan y o f th e informatio n submitte dt o ECTD . I t remain s ECTD' s judgment tha t thes e issue s nee dfurthe r

examination , particularl y befor e onboar dcontrol s ar e determine dt o b e feasibl e fo r ligh t andheavy-dut y trucks . Al

thoug honboar ddurabilit y dat aar e no t available , ECT

D find s tha t onboar dcontro l system s shoul db e a s durabl e a s curren t evaporativ e emission s contro l systems , whic hlas t fo r th e lifetim e o f

th e vehicle . For destimate s th e consume r cos t o f onboar dcontrol s fo r light-dut y vehicle s t o rang e from$3 0 t o $253 . EP Aestimate s tha t th e consume r

cos t o f onboar dcontro l system s wil l b e abou t $2 0 (include s $2.7 0 fo r th e cos t

o f a nonboar dsea l an dpressur e relief) . American Motor s AMC' s concern s wit hthe us e o f onboard control s ar e addressed t o the issue s o f exhaus t an d evaporative emission s interactions , feasiblityo f vehicle s using smal l engines , costs , an d light-duty truc k feasibility . Wit hthe exceptio n o f feasibilityfor light

dutytrucks , AMC' s concern s hav e bee n examine d in detai l b ythe AP I study . EPA' s analysi s o f tha t dat a i s tha t refueling los s control s ar e feasibl e for light-dutyvehicle s a t a consume r cos t o f approxi

matel y$17 . V . Conclusion s Feasibilit y An Analysi s o f th e availabl e informatio n ha s shown tha t onboar d refuelin g los s control s ar e feasibl e fo r light-dut y vehicle s designe d t o mee t lo wexhaus t an

d evaporative emissio n standard s (0.4 1 HC , 3. 4 CO , 1. 0 NOx an d 2. 0 Evap.) . However , the feasibilityfor light-dutytrucks , particularl ythe assuranc e tha t onboard contro l systems ar e compatibl e wit ha 2 gra mevaporativ e emissio n standard , ha s no t bee n established . Feasibilit yfo r heavy-dut ygasolin e vehicle s ha s no t bee n established . A n analysi s o f informatio n an d tes t dat a presente d t o EPA regarding the contro l o f light-dutyvehicl e refuelin g emission s offer s the following conclusions : 1 . Onboard contro l systems i n laborator yus e situation s can contro l in exces s o f 97 % o f th e uncontrolle d hydrocarbo n refueling losses .P.2 8

-26
-
2 . Th e sam e system s i n laborator yus e situation s ca n contro l i n exces s o f 97 % o f th e uncontrolle d benzen e refuelin g losses . 3 . Tes t result s fro m tw o light-dut yvehicle s equippe d wit h three-wa ycatalysts , feedbac k carburetors , and prototyp e refuelin g los s system s sho wtha t tailpip e C O emission s rang e fro ma 0 t o 8 % increase . Tes t result s fro mth e sam e vehicle s sho wtha t engine-ou t C O emission s rang e fro ma 0 t o 14 % increase . 4 . Emissio n dat a fro mtw o conventiona l oxidatio n catalys t equippe d light-dut yvehicle s sho wtha t tailpip e C O emission s rang e fro m

a 0 t o 10 % increase . Dat a fro mon e o f th e conventiona l oxidatio n catalys t vehicle s sho wtha t engine-ou t C O emission s increas e b y1 0 t o 20% . 5 . Th e additio n o f refuelin g los s control s t o light-dut y vehicle s doe s no t significantl yaffec t evaporativ e emissio n losses . 6 . Mino r increase s i n C O exhaus t emission s see n fo r som e vehicle s ca n probabl yb e controlle d bymino r chang e t o eithe r th e refuelin g los s contro l syste mo r t o th e exhaus t emissio n contro l system . However , th e additio n o f refuelin g los s control s wil l likel ymak e i t mor e difficul t t o certif ysom e vehicle s t o th e 3. 4 g/m i standar d a t 50,00 0 miles . 7 . Onboar d control s d o no t affec t vehicl e fue l economy . 8 . Onboar d control s d o no t affec t vehicl e driveability . 9 . Refuelin g los s contro l system s fo r light-dut yvehicle s ar e estimate d t o add $1 7 t o th e vehicl e sticke r price . Th e $1 7 estimat e doe s no t includ e th e cost s associate d wit hth e fillpipe / nozzl e sea l o r pressur e relie f valve . Th e consume r cos t o f a sea l and pressur e relie f i n th e fillpip e i s estimate d t o b e abou t $2.70 . Th e cos t o f a sea l o n th e nozzl e shoul d b e roughl yth e sam e a s th e cos t fo r a Stag e I I nozzle . However , i t i s recommende d tha t al l component s o f a n onboar d contro l syste mb e locate d o n th e vehicle . Lea d tim e Onboar d refuelin g los s contro l ca n b e implemente d fo r 198 4 mode l yea r light-dut yvehicles , provide d tha t potentia l proble mP.2 9
-27
-

area s sucha s the design an d developmen t o f effective fillpipe / nozzl e seal s an

d pressur e relie f valve s d o no t requir e additiona l hardwar e demonstratio n programs . I t i s anticipate d tha t th e fillpipe/nozzl e sea l an d the contro l feasibilityfor light an d heavy-dut ytruck s ar e issue s whic hca n b e resolved durin g the NPR

M process . ECTD estimate s tha t a minimu mo f tw

o year s leadtim

e wil l be require d b

ymanufacturer s for developmen t (purg e syste moptimiza

tion , design an

d verificatio n o f fillpip e sea l mechanisms ) an d productio n toolin

g change s (toolin

g associated wit hfabricatio n an d relocatio n o f newevaporative contro l components) . Thes e estimate s ar e based in par t upo n dat a provide d b ymanufacturer s relating t o carbureto r toolin

g changes , an

d in par t upo n dat a supplied b yG M relatin g t o retoolin g change s fo r bodypane l modifications . Additiona l tim

e wil l b e require d for EP At o develop a certificatio n typ e tes t procedur e an d issue regulations ; however , the certifica

tion procedur e developmen t can overla p the production toolin g lea d time . Therefore , th e projectio n i s tha t a n NPR M can be published in 198 0 wit hfina l rule s promulgate d b y198 1 wit hthe earlies t possibl e implementatio n dat e being 1984 . (Se e lea d tim e chart , Figur e 1) . Complianc e Cost s ECTD estimate s tha t certifying light-dutyvehicle s for compli

anc e wit ha refuelin g los s standar d wil l requir e a n additona l one-hal f person-yea r a t th e EPA-MVEL . Thi s i s based on a n estimat e o f 100-15 0 refueling los s test s per year . Facilit ymodifications / equipmen t procurement s wil l cos t fro m$30 K t o $80K . Apotentiall ysignifican t impac t on refuelin g los s complianc e cost s i s Inspection/Maintenanc e testin g o f light-dutyvehicles . EP Aha s no t developed , an d i s no t awar e of , a vali d I/M tes t for determining the performanc e o f evaporative emissio n contro l sys tems . Monitoring the performanc e o f in-us e refuelin g los s contro l systems wil l be difficul t an d cumbersome . A

t thi s time , i t maybe assumed tha t the onboard complianc e cost s associated wit ha n I/M tes t wil l b e equa l t o the cos t o f Stag e I I enforcement . VI . Recommendation s for Futur e Wor k 1 . ECT D recommend s tha t additiona l hardwar e testin g b e conducte d t o determin e the optima l fillpipe-nozzl e seal . Addition

ally , the operatio n an d durabilit yo f a fillpip e or nozzl e pressur e relie f (includin

g overfil l protectio n for liqui d expansion ) mus t be demonstrated . Th e us e o f a n onboard liqui d tra p sea l (submerged fill ) a s a

n alternative t o elastome r typ e seal s shoul d b e invest

igated .Publis hNPR

M Fina l Rul e P.3 0 -28
- Figur e 1 Lead Time
Quarter : Develop Certificatio n Tes t Procedur e Continue d Stud

yo f Fillpipe/Nozzl e Sea l Concept s Calenda r Yea r 198 0 198 1 198 2 198 3 198 4 1234 1 1234 1 1234 1 1234 1 1234 1

Decisio n on Sea l Concept s -(Decisio n t o publis hservic e statio n nozzl e requirement s or pu t sea l on vehicle ) EIS , EIA , NPR

M Preparatio n

Manufacturer s Lead Tim

e 198 4 M YP.3 1
-29
- 2 . ECT D recommend s tha t additiona l hardwar e testin g b e conducte d t o asses s th e feasibilit yo f controllin g refuelin g losse s o n light-dut ytruck s an d heavy-dut ygasolin e powere d trucks . 3 . ECTD recommend s tha t the need for controlling refueling losse s fro

mdiese l powere d vehicle s be investigate d sinc e thes e vehicle s ar e predicte d t o represen t a substantia l fraction o f the entir e moto r vehicl e populatio n i n th e 1980's . 4 . ECTD recommend s tha t the bladde r fue l tan k be investi

gated a s a

n alternative t o carbo n adsorptio n technology . I t i s ECTD' s opinio n tha t the theoretica l contro l o f ecvaporative an d refuelin g los s emission s wit hbladde r tank s i s hig han d tha t technica l problems can be solved . I t i s recommende d tha t bladde r tank s feasibilitybe researche d b yfundin

g a hardwar e demonstratio n contract . 5 . Finally , ECTD recommend s tha t method s o f reducin g the cos t o f onboar d refuelin g contro l system s b e examined . Suc h studie s shoul d b e directe d towar d tradeoff s betwee n leve l o f contro l effectivenes s an d cost . I t maybe possibl e t o sacrific e contro l capacit ytha t i s required unde r onl yinfrequen t condition s t o achiev e a proportionall ymor e significan t cos t savings .P.3 2 -30
- Reference s 1 . "Contro l o f Refueling Emissions, " Statemen t b yGenera l Motor s Corporation , Jun e 11 , 1973 . 2 . "Contro l o f Refuelin g Emission s wit ha n Activate d Carbo n Caniste r o n the Vehicl e - Performanc e an d Cos t Effectivenes s Analysis, " Interi mRepor t Projec t EF-14 , prepared for the America n Petroleu

mInstitute , Washington , D.C , Octobe r 1973 . 3 . "On-Board Contro l o f Vehicl e Refueling Emission s - Demonstra tion o f Feasibility, " AP I Publicatio n No . 4306 , Octobe r 1978 . 4 . "Summar

yan d Analysi s o f Dat a fro mGasolin e Temperatur e Survey Conducte d at Servic e Stations, " Radian Corporation , Austin , Texas . Prepare d fo r the America n Petroleu mInstitute , Wash
ington , D.C , Novembe r 1976 . 5 . "Genera l Motor s Commentar yt o th

e Environmenta l Protectio n Agenc yRelativ e t o On-Boar d Contro l o f Vehicl e Refuelin g Emissions, " Marc h1978 . 6 . "Suppplemen t t o Genera l Motor s Commentaryt o the Environmenta l Protectio n Agenc yRelativ e t o On-Boar d Contro l o f Vehicl e Refueling Emissions, " June 1978 . 7 . "Ford Moto r Compan yRespons e t o EPAConcerning Feasibilit yan d Desirabilit yo f a Vehicl e On-Boar d Gasolin e Vapo r Recover y System. " 8 . "For d Moto r CompanyPositio n Concernin g Feasibilit yan d Desirabilit yo f Vehicl e On-boar d Refuelin g Vapo r Contro l Systems, " Novembe r 6 , 1978 . 9 . AMC lette r t o Pau l Stolpman , Augus t 3 , 1978 . 10 . "Cos t Estimation s fo r Emissio n Contro l Relate d Components/Sys
tems an

d Cos t Methodolog

yDescriptions, " Rat han d Strong , Inc. , Lexington , Massachusetts . Prepare d fo r the Environ

menta l Protectio n Agency , An n Arbor , Michigan , Marc h1978 . 11 . "Investigatio n an d Assessmen t o f Light-Dut yVehicl e Evapora tiv e Emissio n Source s and Control, " Exxo n Researc han d Engineering Company , Linden , NewJersey . Prepared for the Environmenta l Protectio n Agency , Jun e 1976 . 12 . Texac o statemen t submitted t o Pau l Stolpman , Jul y18 , 1978 .P.3 3

APPENDI X The Appendixcontain s detaile d description s an d dat a fro

mthe tes t vehicle s an

dfillpipe/nozzl e seal s whic hwer e used i n the mos t recen t testin

g an devaluatio n o f refueling los s contro l systems . Exxo n Tabl e A- l present s a descriptio n o f al l Exxo n tes t vehicles . Figur e A- l i s a schemati c o f the basi c contro l syste mdesigne d fo

r the Chevrole t Capric e an d the For

d Pinto . Th e refueling emission s (RCS ) caniste r control s bot hrefuelin g emission s an d diurna l evaporative emissions ; the evaporative emission s (ECS ) caniste r control s carbureto r ho t soak losses . Exxo n investigated severa l differen t purg e mechanisms , including combination s o f manifol d vacuu man

d ventur i vacuum , an d tw o stag e purg e contro l valve s controlle d b

yfue l volume , bu t ventur i vacuum , whic hi s propor tiona l t o engin e ai r flow , i s the mos t effective purgin g method . Exxon' s contro l syste mi s designe d t o maintai n the tota l purg e ai r volume (RS C + ECS ) equa l t o the purg e ai r volume o f the unmodi

fie d vehicle' s evaporative contro l system . The ai r blee d contro l valve , show n i n Figur e A-l , i s necessar y becaus e th

e RC S canitse r i s purged mor e efficientl y(highe r hydro
carbo n purg e pe r uni t volum e o f air ) tha n th e unmodifie d ES C system , thereb

yresulting in riche r A/ F mixtures . Thi s ai r bleed ma yno t be necessar

yfor othe r vehicle s wit hfeedbac k carbureto r controls . Figur e A- 2 i s a plo t o f th e RC S caniste r purgin g a s a function o f time . Thes e dat a ar e based on consecutiv e LA- 4 driving days . A s noted , the RC S syste mi s purged a t a rat e o f about 4 litres / min. , whic hcorrespond s t o a tota l caniste r purg e volum e o f abou t 4 0 litre s during a

n LA- 4 driving cycle . Mobi l Specification s fo r the vehicl e Mobi l ha s modifie d for refuel
in g los s contro l ar e summarized a s follows : Vehicle : 197 8 Californi a Pontia c Sunbird Engin e Size : 15 1 cu . in . L- 4 Interi a Weight : 300 0 lbs . Emissio n Contro l System : Exhaust : 3-wa

ycatalys t wit hfeedbac k carburetor , EG R Evaporative : Carbo n caniste rA- 2

Fue l Tan

k Capacity : 18. 5 gallon s The productio n vehicl e i s modifie d for controlling refueling emission s b

yenlarging the existing carbo n canister , (on e caniste r control s refueling , diurnal , an d ho t soak loss) , enlarging the vapo r line betwee n fue l tan k an d canister , redesigning the vapor / liqui d separator , an d installin

g a purg e contro l orific e betwee n the caniste r an

d intak e manifold . Aschemati c o f the Sunbird' s contro l syste mi s shown i n Figur e A-3 . Variou s flo wcontro l orifice s wer e inserted i n th e caniste r purg e line bu t bes t result s ar e obtaine d wit ha n orific e o f 0.10 0 in . diameter . Mobi l use s 155 0 grams o f Calgo n BPL-F 3 carbo n fo r thei r contro l system , which assume s a 20 % safetyfactor . Thi s quantit yo f carbo n i s based o n a 90 % fil l o f the 18. 5 gallo n tank , an d assume s a hydrocarbo n loadin g o f si x grams per gallo n o f dispense d fuel . The working capacit yo f the caniste r i s approximatel y24 0 grams . The basi c component s o f th e caniste r contro l syste mar e show

n i n Figur e A-4 . The ported vacuu mpurg e contro l valv e i s fro ma 197 8 Chevrole t Impal a evapora tiv e canister , whil e th e tw o fue l tan k vapo r valve s (tw o ar e used t o reduc e th

e pressur e drop during the refueling operation ) ar e carbureto r bow l valve s fro ma 197 8 Impala . Using tw o fue l tan

k vapo r valve s result s in fillpip e pressure s a s lo was tw o inche s o f wate r pressur e during refueling . Th e fue l tan k vapo r valve s ar e als o controlle d b ymanifol d vacuu msuc htha t th e vapo r valve s ar e close d whe n manifol d vacuu mi s presen t at the contro l port . Atlanti c Richfiel d Compan y Figur e A- 5 show s the fillpip e sea l whic hARC O ha s develope d an d tested for durability . Table s A- 2 an d A- 3 ar e typica l o f the durabilit yresult s obtaine d wit hthi s seal . Figur e A- 6 i s an exampl e o f a prototyp e combinatio n fillpipe/nozzl e sea l whic hha s bee n develope d an

d evaluate d b

yARCO . Ford Th e vehicle s whic hFor d ha s used for refueling los s testin g ar e show

n i n Tabl e A-4 . Asingl e 4.3 5 1 caniste r i s used i n the Mustang , whil e a due l caniste r system , 82 9 m l an d 3. 4 1 , ar e used for controlling carbureto r vapor s an d diurnal/refueling losses , respectively , in the Pinto . Th e purg e systems for the Mustang an d the Pint o ar e show

n i n figure s A- 7 an d A-8 . Figure s A- 9 an

d A-1 0 ar e plot s o f caniste r loadin g versu s tes t procedur e sequence . Thes e plot s indicat e tha t Ford' s refuelin g los s contro l syste mi s quit e sensitiv e t o th e particula r tes t procedur e whic hi s used t o quantif ythe refueling control/exhaus t emissio n interaction .P.3 5
A- 3

Tabl e A- l Vehicl e Description s
Fue l Tan k Engin e Displacement / Capacit y Mak e Mode l Configuratio n Contro l Systems (gallons ) Chevrole t Capric e 5. 0 litr e (30 5 CID)/V- 8 Ox . Cat. , AIR , EG R For d Pint o 2. 3 litr e (14 0 CID)/L- 4 3-Way , Ox . Cat. , AIR , EG R Plymout hVolar e 3. 7 litr e (22 5 CID)/L- 6 Ox . Cat. , AIR , EG R Chevrole t Chevett e 1. 6 litr e (9 8 CID)/L- 4 Ox . Cat. , AIR , EG R 2 1

1 3 1 8 1 2 0

. 0 0 5P.3 6 

### Tabl e A- 2 FILLPIP E MODIFICATION ROTARY SEAL-C R 753 8 LEA K RAT E A S AFFECTE D BY FILLNEC K PRESSUR E AND WEA R NO . O F SPOUT INSERTION S 0 10 0 10 0 10 0 10 0 10 0 10 0 10 0 10 0 10 0 10 0 TYP E

SPOUT
Smoot h Rough Smoot h Rough Smoot h Rough Smoot h Rough Smoot h Rough CUMULATIVE

INSERTION S 0 10 0 20 0 30 0 40 0 50 0 60 0 700* * 80 0 90 0 100 0 FT 3 

### /MI NLEA K * @ 5 " W.C . 0 0 0 0 0 0 0 0 0 0 0 

### e15 " w.c ,

0.00 1 0.00 1 0.00 1 0.00 1 0.00 1 0.00 1 0.00 1 0.00 1 0.00 2 0.00 2 0.00 2



### * Lea k rat e averag e o f si xnozzl e insertions . * * Expecte d numbe r o f insertion s during vehicl e life .

RGJ:i p 7/13/7 8P.3 7



### Tabl e A- 3 FILLPIP E MODIFICATION ROTARY SEAL-C R 753 8 EFFEC T O F LIQUI D AND VAPO R GASOLINE SOA K ONSEAL I D AND LEA K RATE * HOUR S O F LIQUI D SOA K 0 1 6 3 5

-

-

-

-

-

-

_ 

### TOTAL WEEK S

O F VAPO R SOA K 0 0 

# o 2 3 4 5 6 7 8 SEA

L ID,IN . .71 2 .71 2 .71 1 .70 5 .69 9 .70 1 .70 3 .69 8 .69 3 .69 1 FT 3 

### /MI N

@ 5 " W C 0 0 0 0 0 0 .00 1 0 0 .00 1 LEAK* *

@ 

### 15 " W C 0 0 0 0 .00 1 .00 1 .00 1 0 .00 1 .00 2

* Vapo r an

d liqui d soak a t 72°F . * * Lea k rat e averag e o f nin e nozzl e insertions ,

RGJ:i p 7/13/7 8Figur e A- l



# EVAPORATIV E AN D REFUELIN G EMISSION S CONTRO L SYSTEM S



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