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VEHICL E ONBOAR

D REFUELIN G CONTRO I

AP I PUBLICATIO N NO

. 442 4 HEALT H AN D ENVIRONMENTA L SCIENCE S DEPARTMEN T MARC H 198 6

3

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America n Petroleu m Institute 122 0 L Street , Northwest Washington , V.C. 2000 5 ri l 

# 4 > P. 2

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# 1

### PROGRA M OVERVIE W VEHICL E ONBOARD REFUELIN G CONTRO L AP I Publicatio n No . 442 4

INTRODUCTION Thi s stud

yi s a supplemen t t o th e AP I onboar d refueling programconducte d i n 1978. * I t update s th e earlie r wor k b y eguipping lat e mode l automobile s wit h onboar d refueling vapo r contro l systems , an d verifying performanc e wit h gasolin e mor e volatil e than th e nor m o f summertime commercia l fuels . Th e 197 8 AP I stud

youtfitte d four car s wit h refueling vapo r contro l system s tha t consistentl yachieve d ove r 96 % contro l o f refueling emissions . Th e curren t program , involving thre e cars , exceede d the"earlie r result s b yattaining highe r level s o f contro l efficiencies . I n addition , ne wsafet ycomponent s wer e developed , an

d th e filling requiremen t wa s investigate d t o achiev e simplification . RESULT S Refueling emissio n contro l efficiencie s o f 98+ % wer e achieve d o n al l vehicle s unde r extrem e summertime condition s o f 11. 5 ps i RV

P gasolin e dispense d a t 88°F . Exhaus t emission s wer e no t affecte d byth e onboar d systemo n on e car . Smal l increase s i n exhaus t emission s o f th e othe r car s di d no t caus e federa l standard s t o b e exceeded , excep t fo r carbo n monoxid e i n th e cas e o f on e ca r whic h di d no t mee t tha t standar d eve n befor e modification . Thes e smal l increase s coul d b e eliminate d through furthe r optimizatio n o f th e systems . Contro l o f evaporativ e emission s wa s improve d t o th e exten t th e presen t standar d o f 2. 0 gram s pe r test , prescribe d fo r 9 ps i RV P certificatio n fuel , wa s me t wit h a fue l o f 11. 5 ps i RVP , a mor e volatil e fue l tha n mos t commercia l summe r gasoline . N o advers e effect s o n driveabilit ywer e observed . Th e onboar d system s ar e simpl e i n desig n an d construction , an

d shoul d b e readil yadaptabl e t o th e usua l automotiv e productio n methods . From

th e user' s poin t o f view , th e ac t o f refueling vehicle s equippe d wit h thes e system s shoul d no t b e perceptibl y differen t fro

m refueling curren t vehicles . •"Onboar d Contro l o f Refuelin g Emissions , Demonstratio n o f Feasibility" , AP I Publicatio n #4036 , October , 1978 .P. 4



### PROGRA M FEATURE S Thre e car s wer e studied : 1 . 198 5 Buic k Centurywit h 3. 8 lite r V 6 por t fue l injecte d engin e an

d 15. 5 gallo n fue l tank . 2 . 198 5 Dodg e 60 0 wit h 2. 2 lite r 4 cylinde r throttl e bod yfue l injecte d engin e an

d 1 4 gallo n fue l tank . 3 . 198 4 Pontia c Parisienn e wit h 5. 5 lite r V 8 feed-bac k carburete d engin e an d 2 5 gallo n fue l tank . Th e Pontia c wa s include d i n th e stud ya s a n extreme cas e o f potentiall yhig h refueling emissions . Th e larg e fue l tank , an d shor t rea r fillpip e o n th e vehicle , mak e i t a mor e difficul t task s t o achiev e a hig h leve l o f contro l efficiency . T o preven t vapo r los s during refueling , th e systemdevelope d fo r th e Buic k ha s a liqui d sea l i n th e fillpip e provide d b ya U-shape d dip"i n th e pip e insid e th e fue l tank . System s develope d fo r th e Dodg e an

d Pontia c hav e n o specia l sealing arrangements . The yrel yupo n th e flo wo f gasolin e dow n th e fillpip e t o serv e a s a barrie r t o th e escap e o f vapor s ou t th e productio n fille r nec k t o th e atmosphere . Tw o differen t safet yvalv e alternative s wer e employe d t o clos e of f th e vapo r line , an d thu s guar d agains t fue l los s fro mth e tank , shoul d th e ca r accidentall yrol l over . Also , fue l tan k overfil l preventio n technique s tha t completel yeliminat e spit-bac k an

d spillag e wer e developed . Thes e system s ar e full y compatibl e wit h existin g gasolin e nozzle s operatin g wit h automati c shu t off . Th e EP Aemission s tes t procedur e propose d fo r onboar d refueling control s wa s use d i n al l cases . Th e following contracto r report s presen t th e detail s o f thi s program .P. 5

DA N 86M-11 3

ONBOAR D CONTRO

L OF REFUELIN

GEMISSION S - SYSTE M DEMONSTRATIO

N O N A 198 5 VEHICL E

Repor t Prepare

d for th

e America nPetroleu

m Institut e Washington , D . C .

B y

Mobi l Research& Developmen t Corporatio n Paulsboro , N

J 0806 6

Februar y 198 6

Prepared by : D . W . Lloy

d W . J . Koeh lP. 6

TABL E OF CONTENT S

EXECUTIV

E SUMMAR

Y INTRODUCTIO

N 1 Objectiv

e .... . 1 Projec t Outline 2 CHARACTERIZATIO

N O F TES T VEHICL E BASELIN E 2 Tes t Vehicl e 2 Tes t Fuel s 3 Baselin e Emission s an

d Tes t Method s 3

- Exhaus t an

d Evaporativ

e Emission s 3 Refuelin

g Emission s .. . 4 Tan k Flo w Characteristic s 5 ONBOAR D SYSTE M DEVELOPMEN

T 6 CarbonCaniste r 6 Fillpipe Sea l an

d Vapor/Liqui d Separator Developmen t .. . 6 Externa l Liqui d Sea l 7 Externa l Liqui d Sea l an d Vapor/Liqui d Separator ... . 8 Interna l Liqui d Sea l 8 Productio

nFillpipe A s Sea l 8 Mechanica l Sea l 9 Vapo r Vent/Rollove r Valv e 9 Fina l Onboar

d Syste m 1 0 Installatio

no hVehicl e 1 0 Refuelin

g Emissio

nTest s 1 0 SELECTIO

N O F CANISTE

RPURGE RAT E 1 1 FINA L SYSTE M TESTIN G- EP A PROPOSED CERTIFICATIO N TES T 1 2 Effec t o f Fue l RV

P o nSyste m Performanc e 1 3 DISCUSSIO

N 1 4 Emissio nContro l Performanc e 1 4 Onboar d Syste m Desig nan d Constructio

n1 5 Fue l RV P Versu s Caniste r Siz e 1 6 Reducin g Potentia l Emission s . . 1 7 REFERENCE S 1 8 

# JP. 7

TABL E O F CONTENT S (CONTINUED )

TABLE S 1 - Onboar d Refuelin g Contro l SystemTes t Ca r 2 - Tes t Fue l Propertie s 3 - Buic k CenturyBaselin e Emissio n Tests , Exhaus t Emission s & Fue l Econom

y 4 - Buic k CenturyBaselin e Emissio n Tests , Evaporativ e Emission s 5 - Uncontrolle d Refuelin g Emissio n Measuremen t Procedur e 6 - Buic k CenturyBaselin e Emissio n Tests , Uncontrolle d Refuelin g Emission s 7 - Externa l Liqui d Seal , Benc h Test s 8 - Externa l Liqui d Sea l wit h Vapor/Liqui d Separator , Benc h Test s 9 - Interna l Liqui d Sea l wit h Vapor/Liqui d Separator , Benc h Test s 1 0 - Productio n Fillpip e A s Liqui d Seal , Benc h Test s 1 1 - Mechanica l Seal , Benc h Test s 1 2 r Refuelin g Test s wit h Complet e Onboar d Systemo n Ca r 1 3 . - PreliminaryCaniste r Purgin g Experiment s 1 4 - Summaryo f Propose d EP ACertificatio n Tes t Procedur e 1 5 - Fina l SystemTes t Result s - EP APropose d Certificatio n Test , Exhaus t an

d Evaporativ e Emissions , 11. 5 ps i RV P Fue l 1 6 - Purg e Dat a - EPAPropose d Certificatio n Test , 11. 5 ps i RV P Fue l 1 7 - Refuelin g Tes t Result s - EPAPropose d Certificatio n Test , 11. 5 ps i RV P Fue l 1 8 - Fina l SystemTes t Result s - EP APropose d Certificatio n Test , Exhaus t an d Evaporativ e Emissions , 9. 0 ps i RV P Fue l 1 9 - Fina l SystemTes t Result s - EP APropose d Certificatio n Test , Exhaus t and Evaporativ e Emissions , 10. 5 ps i RV P Fue l 2 0 - Purg e Dat a - EP APropose d Certificatio n Test , 9. 0 ps i RV P Fue l 2 1 - Purg e Dat a - EP APropose d Certificatio n Test , 10. 5 ps i RV P Fue l 2 2 - Refuelin g Tes t Result s - EP APropose d Certificatio n Test , 10. 5 and 9. 0 ps i RV P Fuel s 2 3 - Effec t o f Tes t Fue l RV P o n Caniste r Siz e 2 4 - Potentia l Emission s Compariso n FIGURE S 1 - Onboar d Refuelin g Emissio n Contro l System 2 - Buic k CenturyTank an d Fillpip e - Productio n Configuratio n 3 - Uncontrolle d Refueling Emissio n Calculatio n 4 - Benc h Tes t Ri g 5 - PreliminaryOnboar d Canister , 8.0-Lite r 6 - Fina l Onboar d Canister , 4.5-Llte r 7 - Externa l Liqui d Sea l 8 - Externa l Liqui d Sea l wit h Vapor/Liqui d Separato r 9 - Interna l Liqui d Sea l 1 0 - Mechanica l Sea l Benc h Test s 1 1 - Nozzle-Actuate d Refueling Emission s Vapo r Ven t Valv e 1 2 - Onboar d Fillpip e Assembl y 1 3 - Onboar d Caniste r Mounte d i n Tes t Ca rP. 8

BCECUTIV

E SUMMAR

Y Thi s repor t present s th e finding s o f th

e Onboar

d Refuelin

g Emissio

nContro l Projec t undertakenb y Mobi l Researchan

d Development Corporatio nunder contrac t t

o th e America

nPetroleu

m Institute . Onboar d refuelin

g contro l technolog

y ha s beensuccessfull y applie d t o a 198 5 mode l vehicl e meetin g today' s stringent exhaus t an d evaporativ

e emissio

nstandards . Refuelin g emission s hav

e bee ncontrolle

d wit h98+ % efficienc y i ntest s wit h9 t

o 11. 5 ps i RV

P fue l at 88°F . Applyin g th e onboar

d refuelin

g contro l syste

m t o th e tes t vehicle— a 198 5 Buick Centur

y wit ha 3. 8 liter , fuel-injecte d V- 6 engine , an

d a feedback controlle

d three-wa

y exhaus t emissio

ncatalyst—require d th e followin

g modifications : (Th e syste m i s show

nschematicall y

i nFigure 1. )

• Th e productio

n1.5-liter evaporativ e emissio

ncontro l caniste r wa s replace d b y a 4.5-liter caniste r t o collec t bothrefuelin g vapor s an

d evaporativ

e emissions . Th

e ne w canister o f activate d carbo nwa s place d i nth e sam e underhoo

d locatio

na s th e productio

nevaporativ

e canister .
• A liqui d sea l (similar t o a sin k trap ) wa s place

d i nth e tan k fillpip

e to . prevent escape o f tan k vapor s durin

g refueling .
• Th e existin

g vapor ven t lin

e linkin

g th e tan k to th e canister wa s replace d b y a large r line to accommodat e th e vapor flo

w durin g refuelin

g withou t excessiv

e bac k pressure .
• . A vapor/liqui d separator an d a vapo r ven t valv e wer e installe

d a s an Integra l par t o f th e fillpip

e withou t changin

g it s locatio

no nth e car . Th

e vapor/liqui d separator prevent s passage o f liqui d fue l to th e canister . Th

e nozzle-actuated vapo r ven t valve , whic hi s open onl y durin g refueling , i s designe d to satisf y

th e safety

requirement fo r preventin

g fue l leakage i nth e event o f a vehicl e rollove r accident .
• Th e purge rat e fo

r th e refuelin

g caniste r wa s increase d somewha t over tha t o f th

e productio

nevaporativ

e contro l caniste r s o tha t th e caniste r coul d be regenerated sufficientl y b y drivin g between refuelings . Thi s wa s done b y usin g a large r flo

w contro l orifice . Th e onboar

d refuelin

g emissio

ncontro l syste

m wa s thoroughl y

teste d accordin

g to a procedur e propose d b y th e U.S . Environmenta l Protectio nAgenc y fo r possibl e us e i ncertificatio ntestin

g o f onboar

d systems . Thi s testin g showe d that :
• Refuelin

g emission s wer e controlle d wit h98+ % efficienc y unde r sever e tes t condition s usin g a typica l 11. 5 ps i RV P gasoline dispense d a t 88° F an d requirin

g automati c shutof f o f a conventiona l nozzl e whe nth e tan k i s fille

d t o capacity .
• Contro l o f evaporativ e emission s wa s improve d to th e extent tha t th

e present standar

d o f 2. 0 g/tes t prescribe d for 9 ps i RV

P certificatio

n fue l wa s me t wit ha fue l o f 11. 5 ps i RVP , typica l o f commercia l gasoline ._EL 9

EXECUTIVE SUMMARY (CONTINUED )

• Th e refuelin g contro l caniste r ca n b e purge d faste r tha n necessaryt o restor e it s capacit yi n th e propose d EP Aprocedur e and withou t an y significan t effec t o n exhaus t emissions . I n additio n t o meetin g thes e performanc e goals , th e systemteste d i s compatibl e wit h existin g gasolin e dispensin g nozzle s and ca n b e fuele d at , a t least , th e sam e rat e a s th e productio n vehicle . Th e systemi s simpl e i n desig n and constructio n an d shoul d b e readil yadaptabl e t o commo n automotiv e productio n method s and materials . N o effect s o n vehicl e driveabilit ywer e observed . Durabilit ytesting wa s beyon d th e scop e o f th e project , bu t non e o f th e component s presen t durabilit yproblem s tha t hav e no t bee n addresse d i n othe r automotiv e components . Fro mth e user' s poin t o f view , refuelin g a vehicl e equippe d wit h thi s onboar d systemshoul d no t b e perceptibl ydifferen t fromrefuelin g curren t vehicles . Finally , dat a ar e presente d t o sho wtha t tes t fue l volatilit yha s a relativel ysmal l effec t o n require d refuelin g caniste r size , an d option s ar e discusse d fo r optimizin g caniste r siz e through desig n change s tha t reduc e th e amoun t o f vapo r displace d fromth e tank .P.1 0

ONBOAR D CONTROL O

F REFUELIN

GEMISSION S — SYSTE M DEMONSTRATIO

N O N A 198 5 VEHICL E

INTRODUCTIO

N Thl B repor t present s th e finding s o f th

e Onboar

d Refuelin

g Emissio

nContro l Projec t undertakenb y Mobi l Researchan

d Development Corporatio nunde r contrac t to th

e America

nPetroleu

m Institute . Tw o technologie s fo

r controllin

g vehicl e refuelin

g emission s have bee nunder consideratio

nb y th e U.S . Environmenta l Protectio nAgency . The

y are th e so-calle

d Stage I I vapor recover y a t servic e station s an d vehicl e onboar

d controls . Th

e feasibility

o f onboar

d control s wa s clearl y demonstrate

d i na 197 8 progra

m conducte

d for AP I b

y Atlanti c Richfiel d Company , Exxo nResearch an d Engineerin

g Company , an

d Mobi l Researchan d Development Corporatio n(1)* . Experienc e wit hStage I I technolog y i nus e i nCaliforni a an d th e Distric t o f Columbi a show

s tha t man

y customer s have considerabl e difficulty i noperatin

g th e equipment , an

d tha t th

e durability

o f th e vapo r captur e component s o f th e fue l dispensin

g nozzle s i s limited . Th e 197 8 AP I progra

m showe d tha t onboard , system s requir e n

o modificatio

no f existin

g servic e statio

nnozzle s an

d ca n b e unobtrusiv

e to th e user . Furthermore , studie s (2 , 3 ) hav e show ntha t onboar d contro l o f refuelin g emission s i s mor e cos t effectiv e tha nStage I I technolog

y whe ncompare

d o nanequa l basis . Th e work reporte

d her e reinforce s th e 197 8 AP I progra

m b y showin g that onboar d technolog

y ca nb e applie

d equall y

wel l to a ca

r meetin

g mor e stringent 198 5 exhaus t an d evaporativ

e emissio

nstandard s wit hth e lates t engin e an d emissio

ncontro l technology . Th e work als o shows tha t anonboar d refuelin

g contro l syste

m ca nImprov

e contro l o f evaporativ e emissions . Objectiv

e Th e objectiv

e o f thi s projec t wa s t o equi p a 198 5 mode l car , representin g up-to-dat e engine an d emissio

ncontro l technology , wit ha full y operationa l onboar d refuelin

g emissio

ncontro l syste

m meetin g th e followin

g performanc e requirements :
• 95 % minimu

m recover

y o f refuelin

g vapor s whenteste d wit h11. 5 ps i RV P gasoline a t 88°F .
• Compatibility

wit hexistin

g gasolin

e dispensin

g nozzles .
• Fuelin

g rat e n o les s tha

nth e maximu

m rat e a t whic hth

e unmodifie

d vehicl e ca

nb e fueled .
• N o significan t effec t o nexhaus t emissions .
• Evaporativ

e emission s o f 2. 0 g/tes t maximu m wit h11. 5 ps i RV

P fuel .
• N o significan t effec t o ndriveability .

•Number i nparenthese s indicat e reference s liste d o npage 18 .P.1 1

- 2 -
Projec t Outlin

e Th e wor k wa s divide

d int o fou

r major phases : 1 . Measurin

g baselin

e exhaust , evaporativ e an d refuelin

g emission s o f th e tes t vehicl e an

d characterizin

g th e flo w behavior o f th

e fue l tan k durin g refueling . 2 . Designin

g an d installin

g th e refuelin

g vapo r collectio

nsyste m t o include a carbo

ncaniste r size

d t o handl e vapo r fro m an11. 5 ps i RV

P fue l a t 88°F , a liqui d sea l t o prevent escap

e o f tan

k vapor s throug

h th e fille r neck , a vapor/liqui d separator t o preven t carryove r o f liqui d fue l to th

e canister , an

d a vapor vent valv e t o satisf y safety requirement s regardin g fue l leakage I na vehicl e rollove r accident . Th

e complet e syste

m i s illustrate

d schematicall y

i n Figur e 1 . 3 . Developin

g a metho

d o f purgin

g adsorbe

d fue l vapo r fro

m th e caniste r durin g drivin

g withou t affectin

g exhaus t emission s or driveability . Th e purge rat e i s se t t o ensur e ampl e caniste r capacity for controllin

g bothrefuelin

g an d evaporativ

e emissions . 4 . Testin

g th e complet e vehicl e to measur e refuelin g emissio

ncontro l efficienc

y an d demonstrat e complianc e wit hexistin g exhaus t an

d evaporativ

e emissio

nstandard s accordin g to EPA' s proposed procedure . Thi s repor t i s organized accordin g t o thes e fou

r phase s o f th

e project .

CHARACTERIZATIO

N O F TES T VEHICL E BASELIN E Th e firs t par t o f thi s projec t Involve d establishin

g a baseline for th e tes t vehicl e I nit s productio nconfiguration . Thi s include d measuremen t o f exhaus t emission s an d fue l economy , evaporativ e emission s an

d uncontrolled refuelin

g emissions , an

d characterizatio

no f th e fue l tan

k an d it s flo

w behavior durin

g refueling . Tes t Vehicl e Th e tes t vehicl e fo

r thi s program , described i nTabl e 1 , i s a 198 5 Buick Centur y wit ha 3.8-liter V- 6 engine an d a four-spee

d automati c transmission . Th e engine i s equipped wit hpor t fue l injection . Th e exhaus t emission contro l syste

m consist s o f a three-wa y catalys t wit ha feedback contro l syste m an d exhaus t ga s recirculatio n(EGR) . Th

e evaporativ

e emissio

ncontro l syste m consist s o f a 1.5-liter carbo ncaniste r containin g approximatel y

40 0 gram s o f activated carbon . Th e car' s fue l tank , show ninFigure 2 , ha s a 15.5-gallo ncapacity . Th

e tan k ha s a side-fil l configuratio nwit ha fillneck approximatel y 4 0 inche s i n lengt h(o f which1 2 inche s i s rubber tubing ) an d havin g aninside diamete r o f 1-1/ 4 inches . Refuelin g vapor s exi t th

e tan k throug

ha second , smalle r line (5/8-inc

hID ) runnin

g paralle l t

o th e fillneck . Thi s line connect s wit hth eP.1 2

- 3 -

fillneck jus t belo

w th e lea d restrictor allowin g vapor s to vent to th e atmospher e durin

g refueling . A

0.048-inc

hdiamete r orific e i nth e to p o f th e tan k allow s ventin

g o f th e fue l tan

k whenth

e syste m i s close

d (fue l ca

p on) . Thi s orific e i s connecte d to th e evaporativ

e emissio

ncontro l caniste r throug h1/4-inc

htubing . To prevent spillage o f fue l i nth e event o f a vehicl e rollover , th e 1/4-inc

hvent lin

e i s bent int o anantisiphonin g "bow-tie " shape . Tes t Fuel s Thre e tes t fuel s wit hnomina l RVP' s o f 9.0 , 10.5 , an d 11. 5 ps i wer e use d i n thi s project . Typica l tes t fue l propertie s ar e giveni nTabl e 2 . Actua l RV P value s wer e generall y withi n+0. 3 ps i o f nomina l values . Measure d RV P value s o f tes t fue l sample s take na t th e tim e o f a tes t ar e reporte d fo r baselin e an d fina l onboar

d syste m tests ; otherwise , nomina l value s ar e use d i nthi s report . Baselin e Emission s an

d Tes t Method s Baselin e exhaust , evaporative , an d refuelin

g measurement s wer e mad e after 4,00 0 mile s o f break-i noperatio no na chassi s dynamomete r usin g a modifie

d AM A durability

drivin g cycle . Exhaus t an

d Evaporativ

e Emission s - Th

e result s o f th

e baselin

e exhaus t emissio

nan d fue l econom

y tests , conducte

d accordin

g t o th e Federa l tes t procedur e (4) , ar e show nI nTabl e 3 . Th

e dat a sho

w tha t th

e ca r me t th

e Federa l standard s fo r al l thre e pollutant s (HC , CO , NO x )o neacho f th e thre e tes t fuels . Th e las t tw

o test s wit hnomina l 11.5-ps i RV P fue l differ fro

m th e earlie r test s i nth

e loadin

g o f th e evaporativ

e contro l caniste r prior to th e preconditionin

g ste p o f th e Federa l tes t procedure . Th e propose

d EP A certificatio

nprocedur e fo

r car s wit honboar

d contro l system

s (5 , 6) , whic h I s discusse

d i nmor e detai l later , require s loadin g th e caniste r t o breakthroug

hprior t o th

e vehicl e preconditioning . However , th e curren t Federa l vehicl e emissio ntes t procedur e doe s no t specify th e conditio

no f th e caniste r prior t o preconditioning . Th e firs t thre e baseline emissio ntest s wit hnomina l 11.5-ps i RV P fue l wer e conducte d wit honl y

a partiall y

loade d canister . T o investigat e th e effect s o f a mor e full y loaded caniste r onth e emission s o f th

e vehicl e i nit s productio nconfiguration , tw o test s wer e conducte

d wit hth

e caniste r loade

d t o breakthrough . Thes e tw o test s showe

d highe r level s o f al l three pollutant s (HC , CO , NO-) . Inparticular , C O increase

d fro m anaverag e value o f 2. 2 g/m i wit hth

e partiall y

loade d caniste r an

d 11. 5 ps i RV

P fue l to 3. 0 g/m

l whenth

e caniste r wa s loade d to breakthrough . Bothset s o f baseline dat a wil l be used late r i nevaluatin g th e performanc e o f th e onboar

d system . I nal l o f th

e baseline emissio

ntest s o f Tabl e 3 , th e caniste r wa s prepare d by , first , purgin

g to a constant bas e weigh t wit hai r a t 4 cubi c fee t pe r minute . Theni t wa s loade d withgasolin

e vapor t o th

e desired loadin

g b y drawin g ai r throug

hth e headspac e o f an18-gallo ntan k containin

g approximatel y

2 gallon s o f gasoline . Th e "partiall y

loaded " caniste r ha dp.ia .

- 4 -

bee n allowe d t o adsor b 2 0 g o f fue l vapor . Th e loadin g t o "breakthrough " wa s don e accordin g t o th e breakthrough criteri a o f EPA' s propose d onboar d tes t procedur e (6 , discusse d later ) using a hydrocarbo n detecto r a t th e outle t o f th e canister . Breakthrough loadin g wa s 5 0 g . Baselin e evaporativ e emissio n tes t result s ar e show n i n Tabl e 4 . Thes e wer e obtaine d accordin g t o the Federa l tes t procedur e concurrentl ywit h th e exhaus t dat a above , usin g a partiall yloade d canister . Th e dat a sho wtha t th e ca r me t th e 2. 0 g/tes t evaporativ e standar d o n th e 9.0-ps i RV P tes t fuel , averagin g 1. 1 g/test . Evaporativ e emission s average d 2. 1 g/tes t o n th e 10. 5 ps i fue l an

d 7. 4 g/tes t o n th e 11.7-ps i fuel . Th e mas s o f hydrocarbon s adsorbe d i n th e car' s evaporativ e contro l caniste r i s als o show n i n Tabl e 4 . Refuelin g Emission s - T o establis h a baselin e fo r th e onboar d contro l system , th e uncontrolle d refueling emission s fromth e tes t vehicl e wer e measured . Refuelin g emission s wer e measure d i n a SHE D (Seale d Housin g fo r Evaporativ e Determination ; Mode l 7500 , manufacture d b yAutomotiv e Environmenta l Systems , Inc. ) meetin g EPArequirement s fo r evaporativ e emissio n determination s (4) , bu t wit h modification s t o permi t passag e o f a fue l deliverylin e int o the SHED . Ashor t lengt h o f 3/4-inc h I D pip e wa s inserte d through , and welde d to , a n aluminu mplat e whic h wa s bolte d ove r a n openin g i n a wal l o f th e SHED . Th e plat e wa s seale d t o th e wal l wit h silicon e sealant . Fue l deliveryhos e (3/4-inc h Aeroqui p hose ) wa s connecte d t o th e pip e i n th e SHE D wal l an d t o the fue l conditionin g car t (AES I Mode l FC C 7800 ) locate d outsid e th e SHED . Insid e th e SHE D a two-foo t lengt h o f th e same hos e wa s fitte d wit h a n OP W 1 Anozzle . Outsid e th e SHED , a fue l dispensin g pum p and mete r wer e positione d t o minimiz e th e hos e lengt h t o th e SHE D wall . Fue l wa s recirculate d continuousl ybetwee n th e fue l conditionin g car t and th e dispensin g pum p t o maintai n th e require d fue l temperatur e throughou t th e system . Al l fue l line s wer e insulated . Recirculatio n wa s stoppe d jus t prio r t o actuatin g th e fue l dispensing pum

p fo r a test . Thi s systemensure d tha t dispense d fue l temperatur e i n th e vehicl e tan k o h completio n o f refuelin g wa s withi n on e degre e (F ) o f th e fue l temperatur e i n th e conditioning cart . Th e procedur e use d fo r measurin g refuelin g emission s i s outline d i n Tabl e 5 . Th e tes t parameters , suc h a s tan k liqui d temperature , dispense d fue l temperatur e an

d fil l volume , wer e take n fromEP Amateria l presente d a t a n Octobe r 198 4 Worksho p (5) . Th e fue l tan k wa s firs t fille d t o 10 % o f capacit y wit h th e specifie d tes t fuel . Thi s fue l wa s the n heate d t o 8 8 t o 93° F keepin g th e tan

k vapo r temperatur e withi n 6° F o f th e tan k liquid . Tw o heatin g blanket s (on e o n th e bottomo f th e tan k fo r heatin g th e liqui d and th e second o n th e to p fo r heatin g th e tan k vapor ) wer e use d fo r temperatur e contro l a s describe d b yEPA . Whe n it s temperatur e reache d 88°F , th e fue l wa s allowe d t o soa k fo r a perio d o f time t o allo wfo r saturatio n o f th e vapo r space . Th e SHE D wa s the n close d an d background hydrocarbo n reading s wer e take n everytwo minute s fo r te n minutes . Th e refuelin g wa s initiate d a t th e en d o f th e te n minutes , an d th e tan

k wa s fille d t o 95 % o f capacit yb y actuatin g th e fue l pum p locate d outsid e th e SHED . Afte r th e refueling , SHE D hydrocarbo n reading s wer e take n fo r te n minutes .- 5 -

Calculatio

no f th e uncontrolle

d refuelin

g emission s fro

m th e abov e procedur e involve d plottin

g th e las t si xminute s o f backgroun d dat a take

nbefor e refuelin

g an d fittin

g a firs t order , least-square s lin e throug

hthes e points . Thi s line wa s the nextrapolate

d ou t t o th e point intim

e te nminute s after refuelin

g i norder t

o estimat e th

e contributio

no f th e backgroun

d emission s to th

e fina l SHE

D hydrocarbo

nreading . Th

e differenc e betweenth e fina l SHED hydrocarbo nreadin

g tenminute s afte r refuelin g an d th e extrapolate

d backgroun

d readin

g a t thi s sam

e tim e wa s considere

d t o b e th e actua l refuelin

g emissions . A

nexampl e o f thi s calculatio ni s show

ni n Figure 3 . Thi s calculatio

nmetho d wa s use

d fo r measurin

g th e uncontrolled refuelin g emission s becaus e tes t experienc e indicate d tha t a ten-minut e perio d afte r refuelin

g wa s require

d t o ensur e complet e mixin g an d a stabl e respons e o f th e hydrocarbo

ninstrumen t t

o th e large quantity

o f hydrocarbo

nvapor release

d fro m th e tan k durin g th e refueling . Usin

g a shorte r mixin

g time—fo r example , tw

o minute s afte r refueling—woul d accoun t fo r onl y approximatel y 60 % o f th

e refuelin

g emission s measure d afte r 1 0 minutes . Th e extrapolatio

n o f th e backgroun

d readin

g wa s don

e to accoun t fo

r th e emission s fro

m th e ope n fue l syste

m afte r th

e refueling , but i t made onl y a smal l differenc e (approximatel y

0. 2 g/gal ) i nth

e fina l results . Result s o f th

e baseline uncontrolle d refuelin

g emission s ar e show nin Tabl e 6 . Emission s averaged 5. 2 g/ga l o f dispensed fue l for th e 9.0-ps i fue l an d 5. 6 g/ga l fo

r th e 10.5-ps i fuel . Uncontrolle d refuelin

g emission s fo

r th e 11. 5 ps i fue l average d 7. 0 g/ga l but result s wer e mor e variabl e (rangin g fro m 6. 4 to 8. 1 g/gal ) tha nwit hth

e other tw

o fuels . Variability ca nb e attribute

d to th e temperature differentia l betweenth e tan k liqui d an

d th e dispense

d fue l (AT) . Th

e lengtho f th

e soa k perio d befor e refuelin

g doe s no t appea r t

o have a significan t effec t o nth e amount o f refuelin g emissions . Tan k Flo w Characteristic s I nadditio

nto baseline emissio ndata , informatio

nwa s als o obtaine

d concernin

g th e operationa l characteristic s o f th e vehicl e fue l tan

k durin g refuelin

g i nth e productio

nconfiguration . Thi s wa s don e usin g a benc

htes t ri g o nwhichth

e fue l tan

k an d fillpipe wer e se t u p i nth e sam e configuratio

n a s o nth e car , a s show

ni nFigure 4 . Th

e us e o f th

e benchri g made i t easier t o evaluat e th

e operationa l characteristic s o f th e fue l tan

k system . Placement o f transparen t line s i nsection s o f th e fillneck allowe

d informatio

nt o be obtaine

d abou t th

e operatio

no f th e nozzl e shutof f mechanism . Th

e automati c shutof f o f th e nozzl e use

d (OP W 1A ) i s actuate

d b y liqui d blockin

g a ventur i ven t tub e locate

d nea r th

e en d o f th e nozzle . Observation s fro

m severa l refueling s suggeste d tha t th

e nozzl e shutof f wa s actuate d b y liqui d bein

g pushe d u p th e tan k vapo r ven t line (se e Figure 2 ) an d ont o th

e en d o f th e nozzle . Refuelin g test s als o revealed tha t th e flo w rat e o f th

e dispensed fue l wa s limite d t o no mor e tha

n9. 0 gal/mi ndu

e t o th e restrictio

no f vapo r flo

w fro m th e tan k create

d b y th e lea d restrictor . A

t dispensed fue l flo

w rate s inth

e range o f 8 t o 9 gal/min , prematur e shutof f o f th e nozzl e occurre

d frequentl y

an d wa s dependent o

nth e positio

no f th e nozzl e i nth

e fillneck .P.1 5

- 6 -

ONBOAR D SYSTE M DEVELOPMEN

T Carbo nCaniste r Development o f a

nonboar

d contro l syste

m firs t require

d th e desig no f a carbo ncaniste r large enoug hto adsor

beffectivel y

th e hydrocarbo

nvapor displaced fro

m th e tank . Th

e caniste r use

d initiall y

i nth e developmen t o f th e onboar

d syste m wa s size

d conservativel y

to ensure complet e captur e o f vapor s an

d to allo

w fo r accurat e evaluatio no f othe r syste

m components , particularl y

th e fillpip

e seal . Th

e caniste r use

d for mos t o f th

e onboar

d syste m developmen t testin g i s show

ni nFigure 5 . I t wa s designe d to hav

e a carbo ncapacity

o f approximatel y

8 liters . Thi s caniste r i s a cylindrical , one-pas s desig

nwit hanope

nbotto m ver y similar to th

e productio

n evaporativ

e canister . Th

e caniste r wa s designe d t o us e th

e sam e purge contro l solenoi d valv e a s th e productio

ncanister . Th

e purge rat e i s controlle

d b y anorific e tha t ca nb e change

d easil y

to stud

y different rates . Th

e caniste r wa s fille d wit happroximatel y 230 0 g o f Westvac o 1 0 x2 5 activate

d carbon , th

e sam e typ e use d i nth e productio

nevaporativ

e contro l canister . Th

e Westvac o carbo

nha s anapparen t densit y o f abou t 0.2 5 g/c c an d a freshworkin

g capacity

o f approximatel y

8 5 g/liter . Th e canister use

d i nth e fina l onboar

d syste m i s show

ni nFigure 6 . Thi s smalle r caniste r ha s a carbo ncapacit

y o f approximatel y

4. 5 liter s an

d wa s size d base d o ndat a obtaine

d wit hth

e 8-liter canister . Thi s canister i s a cubical , two-pas s desig nwit hth

e vapor entr

y an d exi t bot ho

nth e to p o f th e canister . Thi s typ e o f desig

nwa s use

d t o increas e th

e efficienc

y o f th e canister . Th

e caniste r wa s fille d wit happroximatel y 130 0 g o f Westvac o 1 0 x 2 5 carbon . Thi s caniste r als o use s th e productio

npurge solenoi d valv e an d ca naccommodat e different siz e purge orifices . Bothcanister s wer e fabricate d o f material s readil y availabl e i na laborator y machine shop . Th

e housin

g wa s made o f aluminu m sheet ; th

e carbo nwa s hel d i n plac e wit ha plasti c foa m pa d an d wir e mesh . Th

e caniste r design s coul d b e adapte d t o productio

nb y th e sam e method s a s current evaporativ e canisters . Fillpip e Sea l an

d Vapor/Liqui d Separator Developmen t Tw o different sealin

g approache s wer e considere d fo r blockin

g th e escape o f tan k vapor s fro

m th e fillpip

e i nth e onboar

d system . Work i nth e 197 8 AP I progra m (1 ) centere

d aroun d usin g a mechanica l sea l (base d o na commo

ngreas e sea l for a rotatin

g shaft ) a s a mean s o f sealin g th e fillneck durin

g refueling . Th

e nozzl e spout fit s snugl y i nth e greas e sea l whic hi s mounted i nth e fillpipe ontop o f th e lea d restrlctor . Thi s sea l wa s foun d t o be ver y effectiv

e i ncontrollin

g refuelin

g emissions . Mor e recently , th e us e o f a liqui d sea l (similar to a sin k trap ) i nth

e fillnec k had beensuggested b y EP A (7 ) a s a possibl e alternativ e t o th e mechanica l seal . Advantage s envisione

d for th

e liqui d sea l include d bette r durability an d lowe r cost , bot hbecaus e o f th e absenc e o f anelastomerl c sea l tha t migh t be subjec t t o wear . A vapor/liqui d separator use d inth e tan k vapor ven t lin

e i nconjunctio

nwit h a liqui d sea l i s als o describe d i nthi s section .P.1 6

- 7 -

Externa l Liqui d Sea l - Developmen t o f th e liqui d sea l wa s done usin g th e benchtes t ri g designe d t o duplicat e exactl y th e vehicle' s refuelin g system . Us e o f th

e benc hri g made i t easie r to make an d evaluat e change s to th e refuelin

g system . Th

e firs t liqui d sea l test s wer e conducte d wit ha sea l made fro

m one-inchcopper fittings . Th e sea l wa s mounted outside th e tan k an d replace d th e rubbe r portio

no f th e fillneck a s show

ni nFigur e 7 . A

1/16-inc

h diamete r drai nhol e i nth e botto m o f th e U-shape

d tra p wa s use

d to allo

w for pressur e equalizatio nbetweenth

e tan k an d th e to p o f th e fillneck whenth

e tan k ca p i s i nplace . Th

e existin

g tan k vapo r ven t line wa s reroute d t o th e onboar d canister . Initia l refuelin

g test s wit hth

e externa l liqui d sea l syste m reveale

d severa l operationa l difference s fro m th e productio

nsystem . First , eventhoug hth e refuelin

g vapo r ven t line fro m th e tan k wa s no t connecte

d t o th e to p are a o f th e fillneck , th

e nozzl e shutof f wa s successfull y actuated b

y liqui d backin

g u p i nth e fillneck a s th

e tan k becam e full . Second , th e syste m wa s abl e to accep t somewha t highe r flo w rate s tha

nth e productio

nconfiguration . Finally , th e effectiv

e liqui d volum

e o f th e tan k wa s increased b

y approximatel y

3/ 4 o f a gallon . Th e sealin

g efficienc

y o f th e liqui d sea l wa s firs t teste d b y runnin g th e vapor ven t lin

e fro m th e tan k throug

hth e SHED wal l an

d connectin

g i t t o th

e caniste r outside th e SHED . Wit hthi s tes t configuration , an y refuelin

g emission s measured i nth e SHED coul d b

e attributed t o th

e sea l alone . Th

e procedur e used fo

r thes e refuelin

g test s wa s essentiall y th e sam e a s for th

e uncontrolled refuelin g emissio

ntests , wit hth

e exceptio

no f th e calculatio

n procedure . Fo

r thes e test s (an

d al l othe r benchtests) , th e refuelin

g emission s wer e take nto b e th e differenc e betweenth e SHED hydrocarbo

nreadin

g jus t prior t

o refuelin

g an d th e readin

g tw o minute s afte r refueling , eve n thoug hth e readin

g ha d stabilize

d i nmuchles s time . Contro l efficiencie s for al l refuelin g test s i ndevelopmen t o f th e onboar

d syste m wer e calculated usin g th e baseline uncontrolled refuelin g emission s o f th e equivalen t RV

P fue l (e.g. , 7. 0 g/ga l for a n11.5-ps i RV P test'fuel ) a s a basis . Thi s calculatio nprocedur e wa s use d t o avoi d artificiall y increase

d contro l efficiencie s for system s havin g highe r potentia l emission s tha nth e uncontrolled baseline case . Potentia l emission s ar e th e tota l amount o f hydrocarbo

nvapo r emitte

d fro m th e fue l tan

k durin g refuelin

g (SHE D hydrocarbo

ni ngram

s + caniste r weigh t gai ni ngrams) . Th e result s o f th

e sealin

g efficiency

test s for th

e externa l liqui d sea l ar e show ni nTabl e 7 . Contro l efficiencie s for test s wit hboth9.0 - an d 11.5-ps i fuel s wer e 9 8 t o 99 % regardles s o f whethe r fuelin g wa s stoppe

d a t th e 95 % fil l leve l o r whethe r th

e nozzl e wa s allowed t o shut of f automaticall y a t th e 100 % level . N

o spitback wa s observe d a t automati c shutoff . Th e result s o f thes e test s als o sho

w tha t th

e potentia l emission s o f th e liqui d sea l syste m (8. 5 an d 7. 2 g/ga l fo

r th e 11.5 - an

d 9.0-ps i fuels , respectively ) wer e significantl y

highe r tha

nth e uncontrolled refuelin g emissionresult s (7. 0 an dP.1 7

- 8 -

5. 2 g/gal ) o n equivalen t RVP fuels . Thi s increas e i n potentia l emission s wit h th e liqui d sea l systemi s attribute d t o th e entrainmen t o f ai r i n th e fue l i n th e fillpip e durin g refueling , whic h increase s th e amoun t o f vapo r displace d t o the canister .

Externa l Liqui d Sea l an d Vapor/Liqui d Separato r - Th e result s o f th e Initia l liqui d sea l test s wer e encouragin g enough t o justif yfurthe r developmen t o f th e system . On e problemtha t wa s observe d i n th e testing wa s th e splashin g o f liqui d i n th e vapo r ven t lin e a s th e tan k pressur e Increase d jus t prio r t o nozzl e shutoff . T o preven t thi s liqui d frombeing carrie d t o th e canister , a vapor/liqui d separato r (o r surg e tank ) wa s place d i n th e vapo r ven t lin e a t th e leve l o f th e top o f th e fillpipe , a s show n i n Figur e 8 . Surg e tank s mad e fro mone-quar t and one-pin t can s wer e fitte d wit h 1/2-inc h I D inle t an

d outle t line s offse t t o increas e separatio n efficiency . Refuelin g test s wit h thi s systemshowe d tha t th e surg e tan k provide d excellen t vapor/liqui d separation . Liqui d tha t entere d th e vapo r ven t lin e accumulate d i n th e surg e tank , allowin g the fue l tan k bac k pressur e t o increas e a s neede d t o shu t of f th e nozzle . Afte r nozzl e shutoff , liqui d tha t ha d accumulate d i n th e surg e tan

k draine d bac k int o the tank . Th e result' s o f severa l refuelin g test s don e t o evaluat e th e effec t o f th e surg e tan

k o n th e overal l systemperformanc e ar e presente d i n Tabl e 8 ; fo r thes e tests , th e caniste r wa s locate d i n th e SHED . Th e result s sho wcontro l efficiencie s abov e 99 % wit h th e 11.5-ps i fue l wit h bot h th e pin t and quar t surg e tanks . Thes e test s wer e conducte d a t a fil l rat e o f 9. 5 gal/mi n wit h automati c nozzl e shutoff ; n o spitbac k o f fue l wa s observe d a t shutoff .

Interna l Liqui d Sea l - Furthe r testing o f liqui d seal s wa s don e usin g a sea l designe d t o fi t i n th e tan k a t th e en

d o f th e productio n fillneck , a s show n i n Figur e 9 . Thi s interna l liqui d seal , als o calle d a J-tub e (7) , i s als o mad e fromone-inc h coppe r fitting s an d ha s th e sam e 1/16-inc h drai n hol e a s th e externa l sea l fo r pressur e equalizatio n whe n th e tan k cap i s i n place . Th e two-inc h spacin g betwee n th e Interna l sea l an d th e floo r o f th e tan k resulte d fromus e o f availabl e one-inc h fittings ; i t i s no t a critica l dimension . Refuelin g test s conducte d wit h th e Interna l liqui d sea l ar e presente d i n Tabl e 9 . Test s wer e carrie d ou t wit h bot h th e one-quar t surg e tan k an d th e one-pin t surg e tank . Th e dat a sho wcontro l efficiencie s fo r thi s configuratio n a t 99.5 % and abov e wit h th e 11.5-ps i fue l regardles s o f th e fue l flo wrat e o r surg e tan k used . Th e dat a als o sho wtha t th e potentia l emission s fo r th e interna l liqui d sea l systemar e greate r tha n thos e o f th e externa l sea l system . Potentia l emission s wit h th e interna l sea l average d 8. 9 g/ga l wit h th e one-quar t surg e tan k and 8. 5 g/ga l wit h th e one-pin t surg e tank versu s 8. 3 an

d 8. 1 g/ga l wit h th e externa l seal . I n al l tests , th e tank wa s fille d t o automati c shutof f an d n o incidence s o f spitbac k wer e observed . Productio n Fillpip e A s Sea l - Observation s frommanyrefuelin g test s wit h transparen t tubing i n the fillpip e reveale d tha t th e fillpip e wa s largel y fille d wit h liquid . T o explor e whethe r th e liqui d i n a n unmodifie d fillnec k migh t ac t a s a vapo r seal , severa l refuelin g test s wer e conducte d usin g th e productio n fillpip e wit h the vapo r ven t lin e and vapor/liqui d separato r from th e liqui d sea l system s describe d above . Th e result s o f thes e tests , presente dP.1 8

- 9 -

i nTabl e 10 , sho

w tha t th

e unmodifie

d fillpip

e coul d sea l wit hgreate r tha n 99 % efficienc

y whenfuelin

g wa s stoppe

d a t th e 95 % level , but tha t spitback occurre d whe nth

e tan k wa s fille

d to automati c shutoff . Mechanica l Sea l - Development o f a nonboar

d syste m usin g a mechanica l sea l wa s de-emphasize d due t o succes s wit hth e liqui d sea l system . However , t o compare th

e potentia l emission s o f a mechanica l sea l syste m to thos e o f th

e liqui d sea l system , severa l test s wer e conducte d i nwhic ha mechanica l fillpip e sea l wa s simulate d b y usin g a Stage I I nozzl e wit hit s vapo r ven t plugged . A

diagra m o f th e benchri g configuratio nuse d fo r thes e test s i s show ni nFigur e 10 . Th e ven t line t

o th e carbo ncanister wa s attache d b y mean s o f a 1/2-inc

hI D "tee " a t th

e highes t point i nth e productio

nvent line . Th

e result s o f thes e tests , presente d i nTabl e 11 , sho

w that th

e potentia l emission s o f th e mechanica l sea l syste m ar e u p t o 31 % les s (approximatel y

5. 8 g/gal ) wit h11. 5 ps i RV P fue l tha

nthos e o f th

e liqui d sea l system s (approximatel y

8. 1 an d 8. 5 g/ga l for th e externa l an

d interna l seals , respectively , wit hth e smalle r surge tank) . Th e potentia l emission s o f th e mechanica l sea l syste m ar e als o les s tha

nth e uncontrolled refuelin g emission s (7. 0 g/ga l wit h11. 5 ps i RV P fuel ) fro

m th e productio

nconfiguration . Thi s differenc e i s attributed t o th e mechanica l seal' s preventin g ai r fro

m enterin

g th e fillneck - durin

g refuelin

g an d becomin

g entraine

d inth e liquid . An

y entraine

d ai r i s displaced t o th e canister , carryin g alon g additiona l hydrocarbonvapor . Th e large differenc e observe d I npotentia l emission s suggest s tha t ther e i s a tradeof f possibl e i nth e tw o sealin

g approache s betwee nth e greate r caniste r capacity require

d t o contai nth

e potentia l emission s fro

m a liqui d sea l an

d th e greate r complexity o f a mechanica l seal . Withth e mechanica l seal , th e caniste r capacity coul d b

e reduce

d a s mucha s 31% . Vapor Vent/Rollove r Valv e Federa l motor vehicl e safety standard s requir e tha t vehicl e fue l system s b e designe d t o restric t leakag e i nth e even t o f a rollove r accident . I nth e productio

nfue l tan

k o f th e tes t car used i nthi s project , thi s requiremen t i s me t b y mean s o f a restrictiv e orific e (0.04 8 inch ) I nth e tan k ven t whic h lead s t o th

e evaporativ

e emissio

ncontro l canister . I nadditio nt o thi s orifice , th

e 1/4-inchven t line t o th e caniste r i s arranged i nanantlsiphonln g "bow-tie " shape . To contro l leakag e fro m th e large r ven t line needed i nan onboar d refuelin

g emissio

ncontro l system , positiv e closur e o f th

e ven t lin

e woul d b e mos t effective . Thi s coul d b e don e b y a valv e that I s normall y

ope n an d close s onl y

i na rollove r situation , or b y a valv e tha t i s normall y

close d an d open s onl y

for refueling . Th e latte r approachwa s selecte d for thi s project . Norma l ventin g o f th e tan k i s maintained throug hthe restrictiv

e orific e an

d th e antlsiphonln

g "bo w tie. " Thi s productio n1/4-inc

hven t line i s connected t o th

e large r refuelin

g ven t line t o carr y nonrefuelin

g tan k vapor s to th

e canister . Th e nozzle-actuated vapo r ven t valve , designe d an d teste d to provid

e positiv

e closur e o f th

e refuelin

g ven t line a t al l time s othe r tha ndurin g refueling , I s show ni nFigur e 11 . Th e valv e i s mounte

d o nth e to p o f th e fillneck jus t belo w th e lead restrictor an d i s opene

d b y th e insertio

no f th e nozzle , causin g th e lea d restricto r door to rais e th e valv e plunger . A

sprin g i s use

d t o kee p th

e valv e seate d whe nth

e nozzl e i s no t Inserted , an d a diaphrag

m i s 

# JP.1 9

-10 -

use d to sea l th

e mechanica l linkage betweenth e fillneck an

d th e valve . Th

e valv e i s located i nth

e refuelin

g ven t line downstrea m o f th e vapor/liqui d separator . Th

e valv e wa s teste

d i nnumerou s refuelin g test s an

d foun d t o operat e effectively . Fina l Onboar

d Syste m Installatio

no nVehicl e - Development o f th e component s fo

r th e onboar d syste m reveale

d tha t th

e interna l liqui d sea l syste m wit hth

e nozzl e actuated vapo r ven t valv e wa s th

e simples t an

d mos t effectiv

e onboar

d system . Thi s system , whic hals o Include d th e us e o f a one-pint vapor/liqui d separator , a 5/8-inchI D vapo r line an d a 4.5-liter carbo ncanister , wa s installe d o nth e tes t vehicle . Th

e complet e syste

m I s illustrate

d schematicall y

i nFigur e 1 . Installatio

no f th e interna l liqui d sea l fabricate d fro m availabl e one-inch copper fitting s require d tha t th

e tan k level-sensin

g floa t b

e rotate

d 180 ° o

n it s mountin

g ar m s o that th

e sea l woul d no t obstruc t movemen t o f th e float . Som e cuttin

g o f interna l tan

k baffle s als o wa s necessary . Th e vapo r ven t valv e an d th e vapor/liqui d separator (surg e tank ) wer e mounted o nth e fillpip

e s o tha t th

e assembl y

coul d b

e installe

d a s a unit . Thi s assembl y wa s installe

d i navailabl e spac e behin d th e lef t rear quarte r pane l a t th e norma l fillpip e location , a s show ni nFigure 12 . Th e caniste r wa s place d i nth e engine compartment i nth e sam e locatio

na s th e productio

nevaporativ

e canister , a s show

ni nFigure 13 . Th e origina l 1/4-inc

htan k ven t line wa s connecte

d to th e large r 5/8-inc

hvapo r ven t lin

e downstrea

m o f th e vapor ven t valv e adjacen t to th

e tank , allowin

g th e tan k t o ven t i nit s norma l manner . Refuelin

g Emissio

nTest s - Afte r installatio no f th e complet e onboar

d syste m o nth e tes t vehicle , severa l refuelin g test s wer e conducted t o verif y it s performance . Thes e test s wer e conducte d usin g th e tes t parameter s i n EPA' s Jul y

198 5 Draf t Recommende d Tes t Procedur e (6) . Thes e parameter s ar e ver y similar to th

e tes t parameter s use d fo r th e onboar

d syste m developmen t wor k whic hwer e based o nEPA' s Octobe r 198 4 Workshop (5) , wit ha fe w exceptions . First , th e recommende

d range fo

r th e temperatur e differentia l betweenth

e tan k liqui d an

d th e dispense

d fue l i s 2 t o 5° F i nth e newe r procedur e instea

d o f 0 to 5°F . Second , th e tan k vapo r temperatur e i s t o b e kept withi n3° F o f th e tan k liquid , rathe r tha nwithi n6°F . Finally , a s prescribe

d i nth e Draf t Recommende

d Procedure , th

e fina l SHED hydrocarbon reading s wer e take

n6 0 second s (+ 5 seconds ) after th e en d o f th e refueling . Thi s wa s sufficien t tim e fo r a stabilize

d reading . Th e result s o f th

e refuelin

g test s wit hth

e complet e onboar

d syste m installe

d o nth e ca r ar e presente

d i nTabl e 12 . Th e result s sho

w tha t th

e syste m controlle

d refuelin

g emission s wit hanaverag e o f 98.5 % efficiency . Potentia l emission s for th

e ca r syste m wer e lowe r tha

nth e potentia l emission s o f th e syste m teste d o nth e benc hrig . Som

e o f thi s differenc e ma y b e attributed t o th e differen t tes t parameter s used . Th e benc htest s wer e carrie d out usin

g A T' s o f 0° F whic hrepresent s a mor e sever e conditio ntha nth e A T o f 2° F use d i nthes e tests . Som e o f th e decreas e i npotentia l emission s may als o be attribute

d to difference s Inth e back pressur e characteristic s o f th e vapor ven t valve an

d th e 4.5-liter canister relativ e t o thos e o f th

e benchrig . Thes e test s wer e conducte d withautomati c nozzl e shutof f a t th e 100 % fil l leve l wit hno evidenc e o f spitback o nshutoff . Th

e maximu

m rat e a t whic hth

eP.2 0

- 1 1 -

ca r coul d b

e fuele d withou t prematur e shutof f o f th e automati c nozzl e wit hth e onboar d syste m i nplac e wa s determine d t o b e 9. 0 gal/min . Eventhoug hflo w rate s o f u

p t o 9. 7 gal/mi n(th e maximu

m flo w rat e o f th

e fue l dispensin

g cart ) wer e obtaine

d o nth e benc hri g wit hth

e 8-lite

r canister , th

e 4.5-liter canister restricted th e flo w t o 9. 0 gal/min . Thi s flo w rat e is , however , equivalen t t

o th e maximu

m flo w rat e obtainabl e wit hth e productio

n configuration . Th

e effectiv

e tan k volum e (tota l capacity

o f tan k whe nfille

d t o automati c shutoff ) fo r th e fina l onboar

d syste m wa s 15. 6 gallons , a differenc e o f 0. 1 gallo nfro m th e productio

nconfiguration .

SELECTIO

N OF CANISTE

RPURGE RAT E Th e ability

o f th e vehicl e t

o purge th

e onboar

d canister sufficientl y t o allo w fo r effectiv

e contro l o f th

e subsequent refueling , withou t affectin g exhaus t emissions , i s animportant aspec t o f th e onboar

d system . Purgin

g o f th e productio

nevaporativ

e caniste r i s controlle d b y a solenoi d valve , whichi s actuate d b y th e engine Electroni c Contro l Modul e (ECM) . Th e EC M allow s th e caniste r to-purge whenal l o f th e followin

g condition s ar e met : (1 ) th e engin e ha s beenrunnin

g fo r mor e tha

non e minute , (2 ) th

e coolant temperature i s abov e 80°C , (3 ) th

e vehicl e spee

d i s abov

e 5 mph , an

d (4 ) th

e throttl e i s of f idle . Th e purge rat e o f th

e productio

ncanister i s controlle d b y a 0.040-inc

h orific e locate

d i nth e to p o f th e canister . Thi s purge rat e i s designe d t o provid e adequat e caniste r capacity inth e evaporativ

e emissio

nphase s o f th

e Federa l tes t procedure . Fo r example , th

e caniste r loadin

g i nth e diurna l portio no f th e evaporativ

e emissio

ntes t wa s about 1 9 g wit h9 ps i RV P fue l (Tabl e 4) . Purgin

g thi s quantity

o f hydrocarbon s i nth e exhaus t portio

no f th e tes t i s equivalen t t o anaverag e purge rat e o f about 2 g/m l (1 9 g/1 1 ml) . Purgin g refuelin

g emission s fro

m an11. 5 ps i fue l wil l requir e a highe r purge rate . Fo

r example , th

e minimu

m increas e i npurge rat e t o consum e refuelin

g emission s woul d b

e abou t 0. 5 g/m

i (canister loadin

g o f 8 g/ga l [Tabl e 12 ] divide d b y fue l econom

y o f 1 8 mp

g [Tabl e 3]) . A s th e firs t ste p i nadaptin g th e car' s productio

npurge syste

m t o handl e refuelin

g emissions , severa l test s wer e conducte d wit hth

e 4.5-liter onboar

d caniste r t o evaluat e th e ability

o f th e feedback contro l syste m t o compensat e fo r increase

d purge rate s an

d t o determin

e th e maximu

m purge rat e tha t th e syste m coul d accep t withou t affectin g exhaus t emissions . Thes e test s wer e conducte

d usin g th e earlie r EP

A propose

d certificatio

nprocedur e (5 ) fo

r onboar d system

s an d a 12-ps i RV

P tes t fuel . A s prescribe d i nth e earlie r procedure , th

e caniste r wa s loaded t o saturation , tha t is , t o constant canister weight , prior to th e preconditioning . Orifice s rangin g fro m 3/6 4 to 9/6 4 inche s wer e used i nth e onboar

d caniste r t o var

y th e rat e o f purge . Th e ECM-actuate

d solenoi d valv

e controlle

d th e purge timin

g a s i nth

e productio

n system . Th e exhaus t an

d evaporativ

e emissio

nresult s for thes e tests , alon g wit hth

e caniste r weigh t change dat a fo r th e variou s portion s o f th e test , ar e presente

d i nTabl e 13 . Th e result s sho

w a wide variatio

ni nth e C O emission sP.2 1

- 1 2 -

o f th e vehicl e wit hth

e 5/64- , 7/64 - an

d 9/64-inc

horifice s for essentiall y th e sam e amoun t o f hydrocarbo npurge d durin g th e exhaus t emissionportiono f th e test . Result s a t th e highes t purge rate s (7/64 - an d 9/64-inc

horifices ) ar e no t significantl y different fro

m baseline dat a obtained wit hth e evaporativ

e caniste r loade

d to breakthrough—tha t is , i na conditio n comparabl e t o tha t o f th e large r onboar

d refuelin

g contro l canister . Result s a t th e lowes t purg e rat e (3/64-inc horifice ) ar e equivalen t t o th e baseline dat a wit ha partiall y loade d evaporativ

e canister—tha t is , i na conditio n equivalent to present certificatio ntestin

g practices . Th

e 3/64-inchorific e wa s selecte

d for furthe r testin g to confir

m whethe r i t woul d allo w adequat e purgin g o f th e caniste r t o mee t th e evaporativ

e an d refuelin

g contro l requirement s o f th

e propose

d tes t procedure . Th e 3/64-inc

horific e (0.04 7 inch ) i s abou t 38 % large r i nare a tha nth e productio

n0.040-Inc

hpurge contro l orifice .

FINA L SYSTE M TESTIN G- EP A PROPOSED CERTIFICATIO N TES T Th e fina l step i nth

e developmen t o f th e onboar

d contro l syste

m wa s to tes t th e complete-vehicl e accordin g to EPA' s propose

d certificatio

ntes t procedur e (6 ) to evaluat e th

e ability

o f th e syste m t o contro l refuelin g emission s withou t affectin

g exhaus t emissions . Thes e test s wer e conducted usin g th e vehicl e onboar

d syste m describe

d earlie r an

d th e 3/64-inchpurg e contro l orifice . Th e propose

d EP A tes t procedur e fo

r certifyin

g onboar

d tes t vehicle s i s base d o nth e current certificatio nprocedure , but wit hadditiona l part s added t o evaluat e th

e effectivenes s o f th e onboar

d system . A

summar y o f th e propose

d procedur e i s show

nI nTabl e 14 . Th

e tes t i s starte

d b y testin g th e refuelin

g emissio ncontro l efficiency , or th e capacity , o f th

e onboar

d system . Th

e vehicl e i s refuele

d (1 0 t o 100 % fill ) wit ha n11.5-ps i RV P tes t fue l a t 88° F whil e i nth

e SHED . Th

e procedur e use

d for measurin

g th e refuelin

g emission s her e i s th

e sam e a s tha t described i nanearlie r sectio nfor testin

g th e complet e vehicl e onboar d system . Additiona l refueling s ar e the nconducted on th e ca r unti l th

e caniste r reache s breakthrough . EP A define s breakthroug ha s a three-fol d increas e i nSHED hydrocarbo nconcentratio

ni non e minute . Th

e vehicl e i s the

npreconditione

d an d th e present certificatio nprocedur e performe

d a s usual . Followin

g th e ho t soa

k portio

no f th e test , th

e vehicl e I s ru

nthroug

ha serie s o f drivedow

ncycles , eachconsistin g o f a nLA- 4 drivin g cycl e an

d a one-hou r ho t soak , unti l th e fue l tan

k leve l reache s 10 % (th e vehicl e start s th e tes t a t 40 % o f tan k capacity) . Th

e vehicl e i s thenrefueled t o 40 % o f capacity—actuall y

a 30 % refueling—usin g th e standar

d refuelin

g procedure . Th e purpos e o f thi s operatio ni s to tes t th

e adequacy

o f th e caniste r purge b

y refuelin

g wit ha volum

e o f fue l equivalen t t o tha t consume d i ndriving . Th e exhaus t an

d evaporativ

e emissio

ntes t result s usin g thi s proposed procedur e an

d 11.5-ps i RV

P tes t fue l ar e presente d i nTabl e 15 . Tw o test sP.2 2

- 1 3 -

wer e conducte

d wit hth

e onboar

d caniste r loade

d t o breakthroug

ha s propose

d b y EPA, . A thir d tes t wa s conducte d wit hth

e onboar

d canister loade

d t o saturation . Th

e exhaus t emissio

nresult s sho

w that HC an

d N0 Xemission s wer e equivalent t o th e baselin

e dat a for a partiall y loade d evaporativ

e canister i nal l three tests . I non e o f thes e tests , CO emission s wer e highe r tha nth e baselin

e for a partiall y

loade d evaporativ

e canister , but lower tha n th e baselin

e fo r a nevaporativ

e caniste r loade

d t o breakthrough , a s th e refuelin

g caniste r was . Statistica l analysi s o f th e tes t dat a indicate , however , tha t th

e difference s amon

g al l o f th

e CO emission s value s ar e no t significan t a t th

e 95 % confidenc e level . Th e evaporativ

e emissio

nresult s fo

r al l three test s wer e withi nth e 2. 0 g/tes t standar d specifie

d for a 9-ps i tes t fuel . Evaporativ e emission s fo

r th e tw o test s i nwhichth

e caniste r wa s loade d t o breakthroug

hwer e 1. 2 an

d 1. 3 g/test , respectively . Evaporativ e emission s for th

e saturate

d caniste r tes t measure d 2. 0 g/test . Th

e thre e test s combine d ha d a naverage evaporativ e emission s leve l o f 1. 5 g/test , a 78 % reductio nfro m th e averag e o f th

e baselin

e values . Thes e result s provide confirmatio ntha t onboar

d contro l system

s d o hav e th e ability t o contro l exces s evaporativ e emission s fro

m fuel s representativ e o f commercia l volatility levels . Dat a showin

g th e purge characteristic s o f th e onboar

d caniste r durin

g th e entir e tes t sequenc e ar e presente d i nTabl e 1 6 for al l thre e tests . Th e tabl e show s th e caniste r weigh t change fo r eacho f th

e tes t segment s an

d th e cumulativ

e purge fo

r th e entir e test . Th

e preconditionin

g purge d roughl y

th e sam e amoun t o f hydrocarbo na s wa s gaine

d b y th e caniste r durin

g th e diurnal . Th e contractio

no f th e tan k vapor spac e overnight du e to th e coolin

g o f th e tes t fue l cause

d severa l gram

s o f hydrocarbo

nt o b e draw nback int o th

e tank . Th e purge rat e wa s hig henoug htha t fewer tha

nth e si xdrivedow

ncycle s drive

n I nth e test s woul d hav

e beensufficient t o prepar e th

e caniste r fo

r th e 30 % fuelin g (1 1 drivedow

ncycle s woul d be require d t o driv

e dow nth e tan k t o 10%) . A

t th e en d o f th e sixthcycle , th

e cumulativ

e amount s o f hydrocarbo n purge d wer e 84 , 10 9 an

d 14 2 gram

s for th

e three tests , respectively . Thi s i s considerabl y

mor e caniste r purge tha ni s necessar

y to contro l th

e approximatel y 4 0 gram s o f refuelin

g emission s fro

m th e 30 % fil l test . I nth e cas e o f Test s 2 an d 3 , th e cumulativ

e purge afte r si xdrivedow nset s represent s almos t enoug h hydrocarbo

ncapacity

t o allo

w for anothe r complet e (1 0 t o 100% ) refueling . Th e result s o f th

e initia l refuelin

g capacity

test s an

d th e fina l 30 % fil l test s ar e presente

d i nTabl e 17 . Contro l efficiencie s for th e thre e 30 % fil l test s averaged 98.7 % an d wer e equivalen t t o th e refuelin

g capacity

tes t result s whic haveraged 98.6% . Thes e result s illustrat e th e ability

o f th e onboar d syste m t o regenerat e th

e carbo ncaniste r i napproximatel y hal f th

e tim e require

d b y th e certificatio

nprocedure , withou t significantl y affectin

g exhaus t emissions . Effec t o f Fue l RV

P o nSyste m Performanc e To Investigat e th

e effec t o f tes t fue l RV P o nth e performanc e o f th e onboar

d system , severa l test s wer e ru naccordin

g t o th e propose

d onboar

d certificatio

nP.2 3

- 1 4 -
procedur e wit hnomina l 9.0 - an d 10.5-ps i RV

P fuels . Tw

o test s wer e conducte d o neachfuel ; however , th e drivedow

n( 6 LA-4' s an

d ho t soaks ) wa s complete d i n onl y one o f th

e tw o tests . Th e exhaus t an

d evaporativ

e emissio

nresult s for th

e 9.0 - an

d 10.5-ps i RV

P fuel s ar e show

ni nTable s 1 8 an

d 19 , respectively . Th e result s o f th

e baselin e test s ar e show

nfo r comparison . With9-ps i RV P tes t fuels , emission s o f HC an

d CO showe

d no significan t differenc e a t th e 95 % confidenc e leve l whe n compare d wit hth

e baselin

e data , whil e N0 Xemission s showe d a slight increase . Exhaus t HC , C O an d N0 Xresult s wit hth e 10.5-ps i RV

P fue l wer e no t significantl y

differen t fro

m th e baselin

e data , als o a t th

e 95 % confidenc e level . Evaporativ

e emissio

nresult s for th

e onboar

d syste m wer e identica l for th e 9.0 - an d 10.5-ps i RV

P fuels , bothaveragin g 0.8 5 g/test . Thes e result s represen t approximatel y a 25 % reductio

ni nevaporativ

e emission s wit hth e 9.0-ps i RV

P fue l an

d a 60 % reductio

nwit hth

e 10.5-ps i RV

P fuel , compare

d t o th e baseline data . Th e caniste r purge dat a fo r th e 9.0 - an

d 10.5-ps i RV

P fue l test s ar e presente d i nTable s 2 0 an

d 21 , respectively . Th e dat a sho

w agai ntha t th

e hydrocarbo

n purge rat e i s sufficien t t o purge th e caniste r i nmuchles s drivin g tha ntha t specifie

d i nth e propose

d certificatio

nprocedure . Withth e 9.0-ps i RV

P fuel , th e cumulativ

e purge o f th

e caniste r a t th

e en d o f th e sixthdrivedow

ncycl e (approximatel y

18 % o f th

e tan k capacity

consumed ) wa s 9 4 grams . Thi s represent s approximatel y th e potentia l emission s fro m a complet e (1 0 t

o 100% ) refueling . Withth e 10.5-ps i RV

P fuel , a ne t purge o f 11 3 gram s wa s recorde

d a t th e en d o f th e sixthdrivedow

ncycle . Th e result s o f th

e refuelin

g capacity

test s an

d th e 30 % fil l test s for bot h th e 9.0 - an

d 10.5-ps l RV

P test s ar e show

ni nTabl e 22 . The contro l efficiencie s fo

r th e refuelin

g capacity

test s average

d 98.6 % fo

r bothfuels . Th e contro l efficienc y o f th e 30 % fil l tes t wa s 97.9 % wit hth e 9.0-ps i RV

P fue l an d 98.2 % wit hth

e highe r RV

P fuel . Potentia l emission s o f th e 30 % fil l test s wer e lowe r tha nthos e of th

e correspondin

g refuelin

g capacity

tests . Thi s ma y have resulted fro

m weatherin

g o f th e tan k fue l durin

g th e tes t sequence .

DISCUSSIO

N Emissio nContro l Performanc e Th e dat a presente

d i nthi s repor t clearl y demonstrat e tha t a hig hleve l o f contro l o f refuelin g emission s i s feasibl e wit hanonboar d system . Contro l efficienc

y greate r tha

n98 % wa s achieved consistentl y usin g tes t fue l wit ha n RV P o f 11. 5 ps i t o represen t th e volatility

o f gasoline s i nth e marketplac e i n summertime . Thes e result s wer e obtaine d usin g a commo

nservic e statio

nnozzl e operatin

g wit hautomati c shutoff ; n o spitback occurred . I nadditio

nt o controllin

g refuelin

g emissions , th

e onboar

d syste m improve

d contro l o f evaporativ e emission s t o th

e extent tha t th

e presen t standar

d o f 2. 0 g/tes t prescribe d fo r a 9-ps i RV

P tes t fue l wa s me t wit hfue l o f 11.5-ps i RVP .- 1 5 -

Furthermore , ther e wa s n o significant interactio no f th e syste m wit hexhaus t emission s o r fue l economy . Ther e wa s n o evidenc e o f an y effec t o

n driveability

i nth e drivin

g tha t wa s don

e i nth e program , althoug

hn o driveability

evaluatio

nusin g standardize

d tes t method s wa s possibl e i nth e tim e available . No significant effec t o ndriveability

woul d be expecte

d i n vie w o f th e feedback air-fue l rati o contro l syste m o nth e tes t vehicl e an

d th e absenc e o f a

neffec t o

nexhaus t emission s a t th e caniste r purge rat e selected . Onboar d Syste m Desig nan d Constructio

n Th e onboar

d refuelin

g emissio

ncontro l syste

m teste d i s simpl e i ndesig nan d construction . I t shoul d b e readil y

adaptabl e t o commo nautomotiv

e productio

n method s an

d materials , an

d al l component s ca nb e package

d i nth e tes t vehicl e withou t an

y structura l changes . Th e refuelin

g caniste r teste

d ha d a carbo

n capacity

o f 4. 5 liter s (130 0 g o f Westvac o 1 0 x2 5 activated carbon ) compare d t o th e productio

nevaporativ

e caniste r o f 1. 5 liter s (40 0 g o f th e sam e carbon) . Th

e refuelin

g caniste r wa s mounted i nth e sam e underhoo

d locatio

na s th e evaporativ

e caniste r withou t havin g t o relocat e an

y othe r parts . Th

e canister i s patterne d o nproductio

nevaporativ

e canister design s an d coul d b

e manufactured ' b

y th e sam e moldin

g methods . Th e vapo r ven t line to th e caniste r wa s made o f 5/8-inc hI D tubin

g to minimiz e back pressur e a t th e vapo r flo

w rate s encountered durin g refueling . Thi s line coul d b e fabricate

d fro m stee l tubin

g o f th e sam e typ e a s i s use

d fo r th e 1/4-inc hline o f th

e productio

nevaporativ

e emissio

ncontro l system . Further syste m optimizatio

nma y allo w a refuelin

g vapo r vent lin

e diamete r smalle r tha n5/ 8 inch , an

d locatin

g th e caniste r closer t o th e fue l tan

k woul d reduc e th e lengt ho f line required . Modification s a t th e fue l tan

k an d fillpip

e ar e th

e liqui d seal , th

e vapor/liqui d separator or surge tank ; an d th e nozzle-actuated vapo r ven t valve . Inth

e tan k o f th e tes t car , mino r modification s wer e made to th e level-sensin

g floa t an

d t o som

e baffle s to accommodat e th e liqui d sea l .fabricate

d fro m availabl e plumbin

g fittings . I nproduction , th e sea l coul d b

e forme d a s anextensio

no f th e fillpip

e penetratio

nthroug

hth e tan k wal l an

d coul d b e shape d t o fi t availabl e spac e s o tha t no othe r modification s woul d be needed . Alternatively , th e tes t o f th

e sealin

g ability

o f th e productio

n fillpipe (Tabl e 10 ) show s tha t i t ma

y no t b e necessar

y to make an

y change s a t th e tan k end , i f th

e flo w characteristic s o f th e fillpipe a t shutof f ca nb e modified t o preven t spitback . Th e vapor/liqui d separator , o r surge tank , i nth e vapo r ven t lin

e an d th e vapo r ven t valv

e wer e designe

d t o b e mounted o

nth e fillpipe an

d to fi t i n availabl e spac e betweenth e lef t rea r quarte r pane l an d th e trun k side wal l a t th e norma l fillpipe location . Thes e component s coul d be manufactured a s a subassembl y

tha t woul d b

e installe

d inth e vehicl e i nth

e sam e wa y a s th e productio

nfillpipe . Thi s subassembl y woul d be connecte

d t o th e existin

g tan k fil l an d ven t fittings . Th e nozzle-actuated vapor vent valv e i s designe

d to satisf y

th e safet y requiremen t for preventin g fue l leakage fro

m th e tan k i nth e event o f a vehicl e rollove r accident . I t doe s thi s b y keepin g th e refuelin

g ven t line close d a t al l time s othe r tha ndurin g refueling . Thi s arrangemen t maintain s norma l tank.ventin

g an d it s associate

d rollove r protection .- 1 6 -

The vapor/liqui d separator protect s th e carbo ncaniste r fro

m liqui d fue l tha t migh t otherwis e b

e carrie

d alon g b y th e vapo r durin

g refueling . Th

e syste m a s teste d o nth e benchri g als o prevente d liqui d fue l fro

m floodin

g th e caniste r ina simulate

d nozzl e shutof f failure . I nthi s test , fue l overflowed fro m th e fillpipe , a s i t woul d fro m a productio

nfillpipe , withou t generatin g enoug h bac k pressur e t o forc e i t t o th e canister . Thi s behavior o f th e syste m woul d b e sensitiv

e t o vapo r flo

w geometr

y o nan y particular vehicle . I f necessary , a floa t valv

e coul d be Include

d i nth e vapor/liqui d separato r t o provide further protectio

nagains t possibl e caniste r flooding . Withth e syste m tested , fillin

g o f th e tan k ende d i na norma l manner . Nozzl e shutof f wa s automati c an d withou t spitback . Th e tan k leve l a t shutof f wa s withi n0. 1 ga l o f th e nomina l capacity . Overfillin g th e tan k i s no t possibl e i na practica l situatio nbecaus e th

e refuelin

g vapo r ven t become s blocke d b y liquid , leavin

g onl y th e productio

n0.048-inc

horific e i nth

e tan k to p for furthe r slo

w venting . Th e onl y chang e fro

m th e productio

nvehicl e tha t wa s necessar y fo r purgin

g th e refuelin

g contro l caniste r wa s t o increas e th e siz e o f th

e purge contro l orifice ; th

e -are a o f th e orific e wa s increase d abou t 38% . Durability

testin g wa s no t possibl e i nth e tim e availabl e for thi s project ; however , the.syste

m describe

d shoul d no t present an y ne w or unique durability problems . Al l o f th e component s ar e based ondesig nconcept s tha t have bee n prove ni nth e pas t an

d ca nb e manufactured fro

m commo nautomotiv

e materials * Th e carbo ncaniste r i s anenlargemen t o f present evaporativ e contro l canisters . Th

e vapor/liqui d separator coul d b e manufactured fro

m shee t meta l or molde

d o f plastic . Th

e onl y movin g part s ar e i nth

e vapo r ven t valve , whichi s kep t close d b y a sprin

g an d opene d b y nozzl e insertion . Thi s valve als o might b

e forme d fro m shee t meta l or molded o f a suitabl e plastic . Th e diaphrag

m separatin

g th e valv e fro m th e fillpipe (Figur e 10 ) coul d be designed i nvariou s ways , for exampl e a s a bellows-type boo t o f fuel-resistan t elastomer . Th

e materia l coul d b

e th e sam e a s tha t provenI nfue l pum p diaphragms . Fue l RV P Versu s Caniste r Siz e Th e dat a reported abov e sho w tha t tes t fue l RV

P affect s th

e caniste r capacity require d t o contai nrefuelin g an d evaporativ

e emissions . Th

e mas s o f vapo r displaced fro

m th e tan k i nth e prescribe

d 100 % fuelin

g tes t i s th

e controllin

g factor . Evaporativ e emission s ar e les s important tha nrefuelin

g emission s for caniste r sizin

g becaus e th

e caniste r i s loaded t o breakthroug hprior t o th

e evaporativ

e portio

no f th e tes t procedur e an d th e purge rat e durin

g preconditionin

g determine s whethe r sufficien t capacity wil l be availabl e fo r th e diurna l emissio

ntest . Capacity

require

d for refuelin

g emission s I s dictate d b y potentia l emissions . Potentia l emission s an d related caniste r size s a t th

e thre e fue l RV

P level s teste

d ar e summarize

d I nTabl e 23 . Reducin g RV P fro m 11. 5 to 10. 5 ps i reduce s potentia l emission s onl y 12 % an d reduce s required caniste r siz e proportionatel y fro m th e 4. 5 liter s o f carbo n teste d t o anestimate

d 4. 0 liters . Tabl e 2 3 als o show s tha t contro l efficienc

y wa s no t affecte

d b y tes t fue l RVP .P.2 6

- 1 7 -

Reducin g Potentia l Emission s As state

d above , th

e siz e o f th

e carbo ncaniste r require

d i s determine

d b y th e amoun t o f potentia l emissions . At a givenfue l RV P level , factor s suc ha s th e typ e o f fillpipe sea l used—whethe r liqui d o r mechanical—an d th e desig no f th e vapor/liqui d separator Influenc e th e amoun t o f potentia l emission s fro m a particular onboar

d syste m design . Althoug hth e onboar

d syste m development work for thi s projec t centere d aroun d th e us e o f a liqui d seal , th e testin

g conducte

d wit ha mechanica l sea l showe d tha t ther e i s a larg e differenc e i nth e potentia l emission s o f th e tw o sealin

g systems . A

summar y o f th e potentia l emission s o f thes e tw o sealin

g system

s i s presente

d I nTabl e 24 . Th e dat a sho

w tha t th

e potentia l emission s o f th e mechanica l sea l syste m ar e approximatel y

31 % lowe r tha

nthos e o f th

e liqui d sea l system . Base

d o nth e lowe r potentia l emissions , i t i s estimate d tha t th

e require d caniste r siz e for a mechanica l syste m woul d be approximatel y 3. 1 liters . Potentia l emission s ar e lowe r becaus e th e mechanica l sea l prevent s ai r fro m enterin

g th e fillneck an

d becomin

g entrained i nth

e dispense

d fuel , thu s reducin

g th e amoun t o f vapo r displaced to th e canister . Th e differenc e i npotentia l emission s suggest s tha t there i s a tradeof f possibl e betweenth e tw o sealin

g approaches . Th

e lowe r potentia l emission s o f th e mechanica l sea l woul d allo w a smalle r caniste r tha ntha t require

d wit hth

e liqui d seal ; however , th e mechanica l sea l itsel f i s mor e comple xan d i t require s additiona l components . Becaus e th e mechanica l sea l physicall y seal s th e fue l tank , a pressure-relie f valv e woul d b

e require

d t o prevent excessiv e pressur e buildu

p i nth e tan k i nth e event o f a nozzl e shutof f failur e or a blockage o f th

e vapo r patht o th

e canister . Th

e liqui d seal , wit hit s "sin k trap " design , serve s a s it s ow npressure-relie f valve , becaus e tan k pressur e ca nneve r b

e greate r tha

nth e "head " o f liqui d I nth e fillpipe . An

y greate r pressurizatio

no f th e tan k wil l caus e th

e fillpipe t o overflo w a s I t ca

ni n fuelin g curren t vehicles . Als o i nth e event o f a nozzl e shutof f failure , a check valv

e i nth e vapo r line woul d b e needed wit hth e mechanica l sea l t o prevent floodin

g o f th e canister . " Developmen t testin

g ha s als o show

ntha t othe r desig

naspect s o f th

e onboar

d syste m canhav

e a neffec t o

nth e amoun t o f potentia l emissions . For example , a reductio

ni npotentia l emission s o f approximatel y 0. 4 g/ga l wa s seenwit h th e Interna l liqui d sea l syste m whe nth

e one-quar t surge tan k wa s replace

d b y th e one-pin t surge tan k (Tabl e 9) . Furthermore , limite d testin

g suggest s tha t reduction s i nthe potentia l emission s o f th e liqui d sea l syste m ca nb e obtaine d b y recyclin

g tan k vapor int o th

e fillpipe i nth

e regio no f turbulent flo w wher e ai r entrainmen t occurs . Thi s cause s saturate d vapo r t

o b e entraine

d i nplac e o f fres hai r an d reduce s th

e amoun t o f additiona l hydrocarbonvaporized . Evidenc e o f potentia l emissio nreductio

nthroug

hvapo r recyclin

g ca nals o b

e foun d incomparin

g potentia l emission s fro m baselin

e an d liqui d sea l tests . Turbulenc e an d vapo r entrainmen t ar e observed i nboth cases . Th

e lowe r emission s i nth e baselin

e cas e indicat e tha t som e o f th e entraine

d vapo r I s recycle

d tan k vapo r instea

d o f fres hair ; recyclin g doe s no t occur wit hth

e liqui d sea l becaus e th e ven t line I s no t connecte d t o th e fillpipe . Th

e baseline emission s ar e lowe r becaus e les s ai r i s Introduced ; an d sinc e th

e recycle

d vapo r i s alread

y saturate

d wit hhydrocarbons , furthe r vaporizatio

ni s reduced .
2722 HP.2 7

- 1 8 -

REFERENCE S

1 . On-boar

d Contro l o f Vehicl e Refuelin g Emissions , Demonstratio no f Feasibility , Publicatio nNo . 4306 , America nPetroleu

m Institute , Octobe r 1978 .
2 . Cos t compariso

nfo r Stage I I an

d On-boar

d Contro l o f Refuelin g Emissions , America nPetroleu

m Institute , Januar

y 1984 . 3 . Evaluatio

no f Ai r Pollutio

nRegulator

y Strategie s fo

r Gasoline Marketin g Industry , EPA-450/3-84-012a , U . S . Environmenta l Protectio nAgency , Jul y 1984 .
4 . Code o f Federa l Regulations , Par t 86 , Federa l Register , Vol . 24 , No . 124 , June 28 , 1977 .
5 . Onboar

d Contro l o f Refuelin g Emissions , Tes t Procedur e Developmen t an d Preliminar

y Baselin

e Tes t Results , Workshop , U . S . Environmenta l Protectio

nAgency , Octobe r 17 , 1984 . 6 . Draf t Recommended Tes t Procedur e fo r th e Measuremen t o f Refuelin g Emissions , Technica l Report , EPA-AA-SDSB-85-5 , U . S . Environmenta l Protectio

nAgency , Jul y

1985 .
7 . Recen t Development s i nEPA' s Progra m to Evaluat e Onboar d Contro l o f Refuelin

g Emissions , U . S . EPA/AP I Briefing , Februar y 4 , 1985 .P.2 8

Tabl e 1 Onboar d Refuelin

g Contro l Syste

m Tes t Car 198 5 Buic k Centur

y Engine : 3. 8 Lite r V-6 , Multipoin t Fue l Injectio n Transmission : Automati c 4-Speed , Front-Whee l Driv e EP A Inerti a Weight : 3,25 0 l b Emission s Certification : 198 5 U.S . Emissio nContro l System : Exhaust : 3-Wa

y Catalys t wit hClosed Loop Electroni c Contro l o f Air/Fue l Rati o an

d EG R(EG R+ 3 CL ) Evaporative : 1. 5 lite r Carbo nCaniste r (40 0 g o f activated carbon ) Fue l Tan

k Capacity : 15. 5 ga l

2722H/2 4Tabl e 2

Nomina l RVP , ps i Actua l RVP , ps i Distillation , ° F a t IBP 10 % 20 % 30 % 50 % 90 % 

### E P Tes t Fue l Propertie s


### 9. 0 9. 3
8 8 12 3 15 2 18 4 22 7 31 6 

### 37 8 10. 5

10. 5
8 6 11 8 14 6 18 0 22 6 31 8 

### 38 5 11. 5

11. 7
8 4 11 3 14 1 17 7 22 6 31 7 

### 37 6 Specifi c Gravity

0.745 0 0.741 7 0.740 1 Wt . Fractio

nCarbo n0.865 3 0.864 8 0.862 1 Octane R+M 2 mln « 9 1 9 1 9 1

2722H-2 5P.3 0

Tabl e 3 Buic k Centur y

Baselin e Emissio nTests ^ Exhaus t Emission s an dFue l Econom y
Tes t Fue l Exhaus t RVP , ps i H C Partiall y

Loade dEvaporativ e Canister 2 8. 6 0.1 5 9. 1 0.1 4 10. 6 0.1 6 10. 2 0.1 4 11. 4 0.1 7 11. 2 0.1 5 12. 2 0.2 0 Evaporativ e Caniste r a t Breakthrough 3 11. 5 0.1 9 11. 8 0.2 4 Federa l Standar d Emissions , 

### C O

2.0 0 1.6 2 1.8 5 1.8 6 2.4 4 2.0 1 2.2 4

2.9 0 3.10 g/m i

NO* .

0.3 4 0.3 1 0.3 6 0.3 6 0.3 7 0.3 6 0.3 5

0.3 9 0.4 5 Cit y

Fue l Economy , mp g

18. 7 18. 6 18. 9 18. 8 18. 8 18. 5 17. 6

18. 1 17. 7

8. 7 - 9. 2 0.4 1 3. 4 1. 0

1 . Vehicl e mileag e approximatel y 4,00 0 miles . 2 . Hydrocarbo nloadin g i s 2 0 g ove r purge dweight . 3 . Hydrocarbo nloadin g i s 5 0 g ove r purge dweight ; vehicl e mileag e approximatel y

620 0 miles .

2722H/2 6P.3 1

Tabl e 4 Buick Centur

y Baselin

e Emissio

nTests ! Evaporativ

e Emission s
Tes t Fue l RVP , 8. 6 9. 1 10. 6 10. 2 11. 4 11. 2 12. 2 J?s i • .

Federa l Standar

d Diurna l 0.7 2 0.8 2 1.6 9 1.4 7 6.1 3 4.4 7 3.6 1 Ho t Soa k 0.3 6 0.3 6 0.4 4 0.6 6 2.1 8 1.9 3 1.9 3 Tota l

1. 1 1. 2 2. 1 2. 1 8. 3 6. 4 5. 5 Diurna l

19. 5 18. 7 25. 7 24. 9 29. 0 28. 2 28. 5 xgnt v»ain , g

Ho t Soa k 8. 4 7. 8 11. 1 12. 3 16. 6 15. 5 12. 1
8.7-9. 2 

### 2. 0

1 . Vehicl e mileag e approximatel y 4,00 0 miles .

2722H/2 7P.3 2

Tabl e 5 Uncontrolled Refuelin g Emissio

nMeasuremen t Procedure 1

1 . Drai nfue l tan k an d fil l t o 10 % o f capacity (1. 5 ga l i n15.5-ga l tank ) wit htes t fue l a t 88°F . 2 . Afte r vapo r temperature reache s a t leas t 82°F , allo w fue l to soa

k a t 8 8 to 93° F for desire

d soa k perio d wit hth

e fue l ca

p o nan d th e evaporativ

e contro l caniste r hooke d up . Kee

p tan k vapor temperature withi n+ 6° F o f liquid . 3 . A t en d o f soa

k period , remov

e cap an

d plac e nozzl e i nfillneck a t th e desire d flo w setting . Weig

hevaporativ

e caniste r an

d replace . 4 . Clos e SHED door an d record backgroun

d HC reading s ever

y 2 minute s for 1 0 minutes , keepin

g tan k liqui d a t 8 8 t o 93°F . 5 . Operat e fue l pum p outside SHED to fil l tan k t o approximatel y

95 % leve l (13. 0 ga l added t o initia l 1. 5 ga l i n15.5-ga l tank ) wit hfue l a t 88° F + 2°F . 6 . Measur e SHED HC concentratio never y 2 minute s fo

r 1 0 minute s after en d o f refueling .

1 . Base

d o n(5) .

2722H/2 8Tabl e 6 Buic k Centur

y Baseline EmissionTests 1 Uncontrolled Refueling Emissions 2
Nomina l Fue l RVP , ps i 

### 9. 0 9. 0 9. 0 Avg . 10. 5 10. 5 Avg . 11. 5 11. 5 11. 5 11. 5 11. 5 Avg . Refuelin g Emissions , g/ga l 5. 3 

### 5. 3 5. 0 5. 2 5. 5 5. 8 5. 6 7. 0 6. 6 6. 4 8. 1 6. 9 7. 0 Soa

k Time , mi n 1 5 

### 10 0 1 5
6 0 6 5
1 5 1 5 1 5 6 0 6 0 Caniste r Weigh t

Gain , Soak/Test , 8

— /2. 2 15.7/2. 0

— /3. 3
25.4/1. 9 18.6/2. 0

— /2. 7

— /2. 2

— /2. 2 10.5/2. 5

— /2. 6 Tank

Liqui d 8 8 

### 8 7 9 1
8 8 8 9
8 8 9 2 9 2 8 8 8 8 Fue l Temperature , ° F

Tan k Vapo r 8 3 

### 8 4 8 6
8 6 8 7
8 7 8 5 8 4 8 7 8 7 Dispensed

8 9 

### 8 8 8 8
8 6 8 9
9 0 8 9 8 9 8 8 8 8 

### A

T 3



### - 1

- 1 + 3

+ 2 0

- 2 + 3 + 3 0 0

1 . Vehicl e mileag e approximatel y 4,00 0 miles . 2 . Dispensed Fue l Flo w Rat e - 8. 5 g gal/min , Fil l - 10-95 % (13. 0 gal ) for al l tests . 3 . AT - Tan

k Liqui d Temp . - Dispensed Fue l Temp .

2722H/2 9Tabl e 7 Externa l Liqui d Seal , BenchTest s Nomina l Fue l RVP , ps i 

### 9. 0 9. 0 9. 0 9. 0 11. 5 11. 5 Fil l Level 1 % 

### 9 5 9 5 10 0 10 0 9 5 9 5 Contro l

Efficiency , % 2 99. 2 99. 1 98. 3 98. 4 98. 6 99. 2 Actua l

Emissions , 0.0 4 0.0 5 0.0 9 0.0 9 0.1 0 0.0 5 g/ga l Potenti a

Emissions , 

### 7. 0 7. 4 7. 0 7. 3 8. 1 8. 8 i l g/ga l Fue l Temp ,

Dispensed 

### 8 8 8 8 8 9 8 8 8 8 8 8 ° F



# A ^ 0 0

- 2 0 + 1 0

1 . Fil l leve l represent s % o f tan k capacity ; 100 % correspond s t o automati c nozzl e shutof f wit happrox . 1 4 gal . dispense d o nto p o f initia l 10 % fil l o f 1. 5 gal . Dispensed Fue l Flo

w Rat e -8. 5 gal/mi nfo r al l tests . 2 . Sea l only ; caniste r outside SHED . 3 . AT - Tan

k Liqui d Tem

p - Dispensed Fue l Temp .

2722H/3 0Nomina l Fue l RVP , ps i 11.5 * 11.5 * 11.5 5 11.5 5 Externa l Liqui d

Contro l Efficiency , % 2 99. 3 99. 3 99. 7 99. 6 Tabl e 8

Sea l wit hVapor/Liqui d Separator , Benc h

Actua l Potentia l Emissions , g/ga l Emissions , g/ga l 0.0 5 8. 3 0.0 5 8. 3 0.0 2 8. 1 0.0 3 8. 0 Tests 1

Fue l Temp , Dispensed 8 8 8 8 8 8 8 8 

### ° F

A T J

- 1 0 0

- 1

1 . Dispensed Fue l Flo w Rat e - 9. 5 gal/mi nan d Fil l - 1 0 t o 100 % fo r al l tests . 2 . Sea l an

d canister . 3 . A T - Tan

k Liqui d Tem

p - Dispensed Fue l Temp . 4 . One-quar t cylindrica l vapor/liqui d separator . 5 . One-pin t rectangula r vapor/liqui d separator .

2722H/3 1

c o c nNomina l Fue l RVP , ps i 11.5 3 11.5 3 11.5 3 11.5 3 11.5 * 11.5 * Tabl e 9 Interna l Liqui d Sea l wit hVapor/Liqui d Separator , BenchTests 1

Fil l Rat e Contro l gal/mi nEfficiency , % 5. 8 99. 7 8. 5 99. 7 9. 6 99. 5 9. 6 99. 6 9. 7 99. 6 9. 6 99. 7 Actua l Emissions , g/ga l 0.0 2 0.0 2 0.0 4 0.0 3 0.0 3 0.0 2 Potentia l

Emissions , g/ga l 8. 9 8. 6 9. 2 8. 8 8. 4 8. 5 Fue l Temp , ° F

Dispensed A

T z 8 8 0 8 8 - 1 8 8 0 8 8 0 8 8 0 8 8 - 1

1 . Fil l - 1 0 t o 100 % for al l tests . 2 . AT - Tan

k Liqui d Tem

p - Dispensed Fue l Temp . 3 . One-quar t cylindrica l vapor/liqui d separator . 4 . One-pin t rectangula r vapor/liqui d separator .

2722H/3 2

C OTabl e 1 0 ProductionFillpipe A s Liqui d Seal , BenchTests 1
Nomina l Fue l Fil l Rate , Fill , Contro l Actua l Potentia l Fue l Temp , ° F RVP , ps i gal/mi n% Efficiency , % 2 Emissions , g/ga l Emissions , g/ga l Dispensed A T- *
11. 5 9. 5 9 5 99. 9 0.0 1 9. 5 8 8 0 11. 5 9. 5 10 0 Spitbac k - 9. 2 8 8 0 11. 5 9. 2 10 0 Spitbac k - 9. 1 8 8 0

1 . Tes t syste

m had one-quar t cylindrica l vapor/liqui d separator . 2 . Sea l only ; caniste r outsid e SHED . 3 . AT - Tan

k Liqui d Temp . - Dispensed Fue l Temp .

2722H/3 3Tabl e 1 1 Mechanica l Seal , Benchtests 1
Nomina l Fue l Fil l Rate , Contro l Actua l Potentia l Fue l Temp . ° F Efficiency , % 2 Emissions , g/ga l Emissions , g/ga l Dispense d A T3 ~ RVP , ps i gal/mi n
11. 5 11. 5 11. 5 11. 5 9. 5

9. 5 9. 5 9. 5 99. 8

99. 9 99. 9 99. 9 0.0 1 0.0 1 0.0 1 0.0 1 5. 8 5. 8 6. 0 5. 7 8 9 8 9 8 8 8 8 - 1

- 1 0

- 1

1 . Stag e I I nozzl e wit hvapo r line plugged . Fil l - 1 0 t o 100 % fo r al l tests . 2 . Sea l an

d canister . 3 . AT - Tan

k Liqui d Tem

p - Dispense

d Fue l Temp .

2722H/3 4Tes t Fue l

RVP , ps i
11. 5 11. 4 11. 5 11. 6 Fil l Rate ,

gal/mi n
9. 0 9. 1 8. 9 9. 0 Refuelin g Test s

Contro l Efficiency , %
98. 7 98. 4 98. 5 98. 6 Tabl e 1 2

wit hComplet e Onboard

Actua l Emissions , g/ga l
0.0 9 0.1 1 0.1 1 0.1 0 Syste m onCar 1

Potentia l Emissions , g/ga l
8. 0 7. 5 8. 1 7. 8 Fue l Temp ,

Dispensed
8 8 8 8 8 8 8 8 

### ° F



### AT ^
2 2 2 2

1 . 4.5-lite r canister , vapor ven t valve o f Figur e 10 , 100 % fil l t o automati c shutoff , approx . 14. 0 ga l dispense d onto

p o f initia l 10 % fil l o f 1. 5 gal . 2 . A T - Tan

k Liqui d Tem

p - Dispensed Fue l Temp .

2722H/3 5Tabl e 1 3 Preliminar

y Caniste r Purgin

g Experiment s 4.5-Lite r Canister , 12. 2 RV P Test , fue l
4.5 L Caniste r Purge Orifice , in 1 9/6 4 9/6 4 7/6 4 7/6 4 5/6 4 5/6 4 3/6 4 3/6 4 Baseline Averag e Partia l Loading- * Breakthroug

hLoading 3 Exhaus t

H C 0.2 8 0.2 4 0.2 1 0.2 1 0.2 1 0.1 7 0.1 6 0.1 5
0.1 7 0.2 2 Emissions ,

C O 2.7 7 3.6 5 2.4 1 3.1 4 3.0 6 3.1 5 2.2 1 2.2 7
2.2 3 3.0 0 g/m

l NOx 0.4 2 0.2 9 0.3 3 0.3 5 0.3 5 0.3 5 0.3 5 0.3 3
0.3 6 0.4 2 Caniste r Weigh t Change During Federa l TeB t Preconditionin

g Diurna l 

### -6 7 -6 4 -6 8 -7 3 -5 7 -4 7 -4 4 -2 5
1 -2 1 +2 8

+2 8 +2 8 +2 9 +2 8 +3 4 +3 1 +2 8
+2 8 +2 6 Procedur e

Exhaus t 

### -5 2 -5 5 -5 3 -5 2 -5 2 -6 2 -4 3 -3 3
-1 6 -2 6 . g

Ho t Soak 

### +1 8 +1 9 +1 9 +1 4 +1 5 +1 3 +1 2 +1 3
+1 5 + 9 Net

-7 3 -7 2 -7 4 -8 2 -6 6 -6 2 -4 4 -1 7
+2 8 -1 2

1 . Al l test s wit hsaturate d 4.5-lite r canister . 2 . 2 0 g loadin

g o f productio

nevaporativ

e canister . 3 . 5 0 g loadin

g o f productio

nevaporativ

e canister .

2722H/3 6P.4 1

Tabl e 1 4 Summaryo f Propose d EPACertificatio n Tes t Procedure 1

1 . Drai n fue l tan k and fil l t o 10 % o f capacit ywit htes t fuel . Afte r stabilizin g temperature s an d obtainin g initia l SHE D H C readings , fue l t o automati c nozzl e shutof f a t 100 % o f tank capacit ywit h 11.5-ps i RV P fue l a t 8 8 + 2°F . Tan

k liqui d mus t b e betwee n 90-93°F . Obtai n fina l SHE D H C reading s and calculat e refuelin g emissions . 2 . Drai n tan

k and perfor

madditiona l 1 0 t o 100 % refueling s unde r th e sam e condition s unti l caniste r breakthrough i s reached . (Breakthrough , a s define d b

yEPA , i s a facto r o f 3 increas e i n SHE D H C concentratio n i n on e minute. ) 3 . Preconditio n ca r using standar d LA- 4 cycle . 4 . Soa k overnight . 5 . Drai n and fil l tan k t o 40 % wit h 55° F fue l wit honboar d caniste r disconnected . 6 . Conduc t diurna l hea t buil d (60-84° F i n 1 hour) . 7 . Conduc t cold-start , cold-transien t and hot-star t exhaus t emissio ntests . 8 . Conduc t ho t soa k test . 9 . Drivedow

n t o 10 % o f tan

k capacit yusin g a serie s o f LA- 4 drivin g cycle s eac h followe d b

ya 1-hour ho t soak . 10 . Refue l ca r t o 40 % o f tan k capacit yt o tes t adequac yo f purge . Procedure s a s i n Ste p 1 .

1 . Base d o n (6) .

2722H/3 7Tabl e 1 5 Fina l Syste

m Tes t Result s - EP

A Proposed Certificatio nTest 1 Exhaus t an

d Evaporativ

e Emissions , 11. 5 ps i RV P Fue l

Tes t Numbe r 1 2 3 Tes t RVP , 

### 11 , 11 . 11 , Fue l 

### psi

. 7

. 5

. 5 Averag e Caniste r Loadin « » * 22 4 21 7 28 1

1 . 3/64 * 11. 4

11. 2 12. 2 11. 5 11. 8

purg e orific eoooCMCMCM 5 0

5 0

• Exhaus t Emissions .



### H C

0.1 7 0.1 5 0.2 0 0.1 9 0.2 4 

### C

O City Fue l Economy , mp

g Evaporativ

e Emissions , g/Tes t Diurna l Ho t Soa k Tota l

Baseline Dat a 2.4 4 2.0 1 2.2 4 2.9 0 3.1 0 0.3 7

0.3 6 0.3 5 0.3 9 0.4 5 18. 8

18. 6 17. 6 18. 0 17. 7 0.7 6

0.6 9 1.3 0 0.4 5

0.6 1 0.7 2

6.1 3 4.4 7 3.6 1 2.1 8

1.9 3 1.9 3 1. 2

1. 3 2. 0 1. 5

8. 3 6. 4 5. 5

2722H/3 8Tabl e 1 6 Purg e Dat a - EPA

Proposed CertificationTes t 11.5-ps i RV

P Fuel , 3/64 " Purg e Orific e
Tes t 1 Tes t 2 Tes t 3

Loadin g Preconditionin

g Overnight Diurna l Exhaus t Tes t Ho t Soa k Drivedow

nCycle 1 

### 1 2 3 4 5 6 Ne t Caniste r

Wt . Change , g +22 4 

### -2 3

- 5 +3 0 -3 2 +1 1 -2 3 -1 3

- 9

- 7

- 5

- 8 Cumulativ e 

### Purge , g
2 3 2 8

- 2 3 0 1 9 4 2 5 5 6 4 7 1 7 6 8 4 Ne t Caniste r

Wt . Change , g +21 7 

### -2 8 -1 1 +2 7 -3 3 +1 9 -3 2 -1 5 -1 3 -1 1 -1 0

- 2 Cumulativ e Purge , 

### 2 8 3 9 1 2 4 5 2 6 5 8 7 3 8 6 9 7 10 7 10 9 

## 6 Net

Wt . Caniste r Change , g 

### 28 1 -3 4 -1 0 +2 8 -4 3 +1 6 -4 0 -1 5 -1 5 -1 1 -1 0

- 8 Cumulativ e Purge , g 

### 3 4 4 4 1 6 5 9 4 3 8 3 9 8 11 3 12 4 13 4 14 2

1 . Eachdrivedow

ncycl e i s on

e LA- 4 drivin

g cycl e plu s a one-hou r ho t soak .

2722H/3 9

iC oTes t

Numbe r Refuelin

g Tes t Capacity 30 % Fil l Capacity 30 % Fil l Capacity 30 % Fil l Tabl e 1 7 Refuelin

g Tes t Result s - EPA Proposed Certificatio nTest 1 11. 5 ps i RV

P Fue l

RVP . ps i 11. 7
11. 5
11. 5 Fil l Rate ,

gal/mi n 8. 0 8. 0 8. 6 6. 5 8. 0 7. 9 Contro l

Efficiency , % 98. 5 98. 5 98. 6 98. 6 98. 7 99. 0 Actua l

Emissions , 0.1 0 0.1 0 0.1 0 0.1 0 0.0 9 0.0 7 g/ga l Potentia l

Emissions , g/ga l 

### 8. 4
8. 3 7. 9 8. 3 8. 3 Fue l Temp .

Dispensed 8 8 8 8 8 8 8 8 8 8 8 8 

### , ° F



## AT *

- I

- l 0

- 1

- 1 0
1 . 3/64 " Purg e Orifice . 2 . A T - Tan

k Liqui d Tem

p - Dispensed Fue l Temp .

2722H/4 0Tabl e 1 8 Fina l Syste

m Tes t Result s - EPA Proposed,CertificationTest 1 Exhaus t an

d Evaporativ

e Emissions , 9. 0 ps i RV P Fue l
Tes t Tes t Fue l Caniste r Exhaus t Emissions , g/mi Cit y Fue l Evaporativ e Emissions , g/Tes t Numbe r RVP , ps i Loading , g HC C O NOxEconomy , mp g Diurna l Ho t Soa k Tota l
6 7 8. 8

8. 9 Averag e 16 2

16 6 0.1 3

0.2 0 0.1 7 1.3 4

2.0 4 1.6 9 0.3 9

0.4 0 0.4 0 17. 7

18. 4 18. 1 0.3 3

0.4 8 0.4 0

0.4 8 0. 7

1. 0 0.8 5

1 . 3/64 " Purg e Orifice .

2722H/4 1 Baseline Dat a

8. 6 9. 1 2 0

2 0 0.1 5

0.1 4 2.0 0

1.6 2 0.3 4

0.3 1 18. 7

18. 6 0.7 2

0.8 2 0.3 6

0.3 6 1. 1

1. 2Tabl e 1 9 Fina l Syste

m Tes t Result s - EP A Propose

d CertificationTest 1 Exhaus t an

d Evaporativ

e Emissions , 10. 5 ps i RV P Fue l
Tes t Numbe r
4 5 Tes t Fue l RVP . ps i
10. 3 10. 4 Average Caniste r

Loading , g
20 2 19 7 Exhaus t Emissions , g/m i H C C O NO x
0.1 6 0.1 9 0.1 8 

### 1.6 5

2.3 4 2.0 0 0

0 0 Baselin e .3 2

.3 8 .3 5 Dat a Cit y

Fue l Economy , mp

g
18. 0 18. 3 18. 2 Evaporative Emissions , g/Tes t

Diurna l Ho t Soa k Tota l
0.4 2 0.4 0 0.4 8

0.4 1 0. 9

0. 8 0.8 5



### 10. 6 10. 2 2 0

2 0 0.1 6

0.1 4 1.8 5

1.8 6 0.3 6

0.3 6 18. 9

18. 8 1.6 9

1.4 7 0.4 4

0.6 6 2. 1

2. 1

1 . 3/64 " Purge Orifice .

2722H/4 2P.4 7

Tabl e 2 0 Purg e Dat a - EP

A Propose

d Certificatio

nTes t 9.0-ps i RV

P Fuel , 3/64 " Purg e Orific e
Tes t 6 Tes t 7

, . Loadin g Preconditionin

g Overnight Diurna l Exhaus t Tes t Hot Soa k Drivedow

n 

### 1 2 3 4 5 6 Ne t Caniste r Wt . Change , g +16 2 

### -2 8

- 7 +1 4 -2 4 + 4 N.A . Cumulativ e Purge , g

- 

### 2 8 3 5 2 1 4 5 4 1 N.A . 

### Ne

t Wt . Caniste r Change , g +16 6 

### -2 6

- 4 +1 4 -2 6 + 5 -1 8 -1 1 -1 0

- 7

- 7

- 4 Cumulativ e Purge , g

- 

### 2 6 3 0 1 6 4 2 3 7 5 5 6 6 7 6 8 3 9 0 9 4

2722H/4 3P.4 8

Tabl e 2 1 Purg e Dat a - EP

A Propose

d Certificatio

nTes t 10.5-ps i RV

P Fuel , 3/64 " Purge Orific e
Tes t 4 Tes t 5

. Loadin g Preconditionin

g Overnight Diurna l Exhaus t Tes t Hot Soa k Drivedow

n 

### 1 2 3 4 5 6 Ne

t Wt . Caniste r Change , g
+20 2 

### -4 5

- 7 +2 0 -2 8 + 6 N.A .

- Cumulativ e Purge , g

_ 

### 4 5 5 2 3 2 6 0 5 4 N.A .

, Ne t Caniste r

Wt . Change , g
+19 7 

### -3 9 -1 0 +2 1 -3 0 + 6 -2 1 -1 2 -1 1

- 7

- 7

- 3 Cumulativ e Purge , g

— 

### 3 9 4 9 2 8 5 8 5 2 7 3 8 5 9 6 10 3 11 0 11 3

2722H/4 4Tabl e 2 2 Refuelin

g Tes t Result s - EP A Propose d CertificationTest 1 10. 5 an d 9. 0 ps i RVP Fuel s
Tes t Refuelin

g Tes t Fue l Fil l Rate , Contro l Actua l Potentia l Fue l Temp. , ° F Numbe r Tes t RVP , ps i gal/mi nEfficiency , % Emissions , g/ga l Emissions , g/ga l Dispense d A T ^


### 4 5
6 7 Capacity Capacity 30 % Fil l Capacity Capacity 30 % Fil l 10. 3

10. 4


### 8. 8 8. 9 8. 0

8. 1 7. 9 

### 8. 0 7. 0 7. 9 98. 7

98. 4 97. 9 98. 6 98. 6 98. 2 0.0 7 0.0 9 0.1 2 0.0 7 0.0 7 0.0 9 7. 2 7. 4 6. 9 5. 9 6. 0 5. 5 

### 8 8

8 8 8 9 8 8 8 8 8 8 + 1

- 1 0 0 0

1 . 3/64 " Purge Orific e 2 . A T - Tan

k Liqui d Tem

p - Dispense

d Fue l Temp .

2722H/4 5Tabl e 2 3

Fue l RVP , ps i 11. 5 10. 5 

### 9. 0 Effec t o f Tes t Fue l RV P

Potentia l Refuelin

g Emission s g/ga l % Reductio n 8. 3 Bas e 7. 3 1 2 6. 0 2 8 o nCaniste r Siz e Caniste r Siz e for 15. 5 ga l Fue l Tan k 2 Liter s Grams 4. 5 - Teste

d - 130 0 4. 0 - Estimated - 115 0 3. 2 - Estimated - 92 5 Avg . Contro l Efficiency , % 98. 6 98. 6 98. 6

1 . Hydrocarbonvapo r displaced fro m fue l tank ; averag e o f tw o o r thre e tests . 2 . Westvac o 10x2 5 activated carbon .

2722H/4 6

c n oP.5 1

Tabl e 2 4 Potentia l Emission s Comparison 1

System Interna l Liqui d Sea l Mechanica l Sea l
Uncontrolle d Baselin e Averag e Potentia l Emissions , g/^a l 8. 5 5. 8
7. 0 Percen t Decreas e

Relativ e t o Liqui d Sea l



### 3 1 Caniste r Size ,

Liter s o f Carbo n 4. 5 Teste

d 3. 1 Estimated 2

1 . Base d o n benc h test s wit h 11. 5 ps i fuel . 2 . Estimat e base d o n using Westvac o 1 0 x 2 5 carbon .

2722H/4 7

## Figur e 1 ONBOAR D REFUELIN G EMISSIO N CONTRO L SYSTE M

Vapor s Purge d t o Engin e Durin g Drivin g 

## Solenoi d Valve an d 3 

### / M 

### " Orific e Contro l Purgin g % " Vapo r Lin e Productio n Ven t an d —» 4 Rollove r Protectio n Vapor/Liqui d Separato r 4. 5 Lite r Carbo n Caniste r Trap s Vapors Nozzle-Actuate d ^ Vapo r Ven t " Valve

Liqui d Sea l i n Fillpip e Prevent s Escap e o f Vapor s

U l

## Figur e 2 BUIC KCENTUR YFUE L TAN K AN D FILLPIP E PRODUCTIO N CONFIGURATIO N

Fue l Sendin g Uni t - ^ an d Ven t Orific e \ Nozzl e Spou t

i2y 2 

### "

## Figur e 3

UNCONTROLLE D REFUELIN G EMISSIO N CALCULATIO N

tn 

### E 2 

## a a U i 

## x Refuelin g + Backgroun d Emission s

Refuelin g Backgroun d Emission s Ne t Refuelin g Emission s

—i — 

### 8 1 2 1 6 2 0 2 4

Time , Minute s 2 8

c n

## Figur e 4 BENC H TES TRI G

Photo shows fue l tan k an d productio n fillpip e i n th e sam e orientatio n a s o n th e car .P.5 6



# Figur e 5 PRELIMINAR YONBOAR D CANISTE R

& 0 LITER S O F CARBO N
Tan k Vapo rInle t 

# h 1 

# *'- !

'/« " 

### VA" \ \ Purg e Outlet

## Figur e 6 FINA L ONBOAR D CANISTE R 4 £ LITER S O F CARBO N

Solenoi d -. — Suppor t Ttf To p 1, /« ' Ga s Inlet , % " 0 0 Solenoi d Suppor t 

# 1 t f Spac e Modifie d Swagelo k

Plasti c Bulkhea d Unio n Foa m

Baffl e



# * y Vi" x Vi " Vito n Gaske

t 2 "

Cove r Plate

6Vi" - 

# r 7y 2 "

# Figur e 7 EXTERNA L LIQUI D SEA L
Vapo r t o Caniste r 

# I Dotte d Lin e Show s Productio n Configuratio n

Drai n

# Figur e 8 EXTERNA L LIQUI D SEA L WIT H VAPOR/LIQUI D SEPARATO R

Vapo r t o Caniste r

Vapor/Liqui d Separator .

## Figur e 9 INTERNA L LIQUI D SEA L

(J-TUBE )

Vapo r 

# f t o Canister ? 

# y^

Vapor/Liqui d Separato r



### P

# Figur e 1 0 MECHANICA L SEA L BENC H
Vapo r t o Caniste r Stag e I I Nozzl e Used a s Sea l

b >

## Figur e 1 1

NOZZLE-ACTUATE D REFUEUN G EMISSION S VAPO R VEN TVALV E

Vapo r t o Caniste r Vapo r fro m

Vapor/Liqui d Separato r

r' c 

### "~* < 

### ~""~~S"toc k

r — .Doo r 

# H 

# T T -Nozzl e 

# "^j -

## Figur e 1 2 ONBOAR D FILLPIP E ASSEMBL Y

Fillpip e wit h vapo r ven t valve an d one-pin t vapor/liqui d separato r mounte d i n spac e be&ween lef t rear quarte r pane l an d trun k sktewaJI . Vapor/liqui d separato r i s removed i n left-han d photograp h t o show vapo r ven t valve . Viewi s fro m whee l wel l wit h spus h guar d removed.

## Figur e 1 3 ONBOAR D CANISTE R MOUNTE D I N TES TCA R

Photograp h shows onboar d caniste r mounte d i n plac e of productio n evaporativ

e caniste r i n righ t fron t corne r o f engin e compartment . A diagona l corne r brac e tha t passe s ove r th e caniste r wa s remove d fo r th e photograph .P.6 5



### Onboar d Contro l o f Refuelin g Emission s

ARepor t t o th e America n Petroleu mInstitut e Washington , D.C .
January198 6

Exxo n Researc h an

d Engineerin g Compan y Linden , Ne wJerse yP.6 6



### CONTENT S
TABL E O F CONTENT S i LIS T O F TABLE S i i LIS T O F ILLUSTRATION S ii i EXECUTIVE SUMMAR

Y 1 INTRODUCTIO

N3 RESEARC H OBJECTIVE S 4 PROGRA M OUTLINE 5 Vehicle s 5 Onboar d System

Design . 8 Overal l Desig n 8 Charcoa l Caniste r Design . 8 Vapor-Liqui d Separato r an d Vapo r Line s 1 0 Fillnec k Vapo r Sea l .1 0 Purg e System1 1 Tes t Procedur e 1 1 Fuel s 1 5 RESULT S 1 6 Refueling Emission s 1 6 Effec t o f Auto-Shutof f 1 6 Effec t o f Rollover/Overfil l Valves.. . 2 0 Effec t o f Caniste r Siz e ...2 0 Tailpip e Regulate d Emission s .......2 3 Evaporativ e Emission s .2 6 Caniste r Purg e Drivedow n . .2 6 Effec t o f Dispensing FlowRat e .2 6 APPENDI X 2 9P.6 7



### LIS T O F ILLUSTRATION S Figur e 1 Principa l Element s 6 Charcoa l Caniste r 7 Figur e 3 Combinatio n Valv e ..... 9 Figur e 4 Tes t Procedur e 1 3 Figur e 5 Dodg e Refuelin g Emission s 1 7 Figur e 6 Pontia c Refueling Emissions . ...1 8 Figur e 7 ^ Effec t o f Caniste r Siz e on Refueling Emission s 2 1 Figure-8 . Effec t o f RV P o n Evaporativ e Emission s .2 4 Figur e 9 Dodg e Averag e Caniste r Performanc e 2 7 Figur e 1 0 Pontia c Averag e Caniste r Performance....... . .2 8

i iP.6 8



### LIS T OF TABLE S Tabl e 1 Tes t Vehicle s 5 Tabl e 2 Tes t Parameter s 1 2 Tabl e 3 RV

P o f Tes t Fuel s 1 5 Tabl e 4 Effec t o f Auto-Shutof f 1 9 Tabl e 5 Refueling Emission s wit h Combinatio n Valv e 2 0 Tabl e 6 Regulate d Tailpip e Emission s 2 2 Tabl e 7 Evaporativ e Emission s ...2 5

APPENDI X Tabl e Tabl e Tabl e Tabl e Tabl e Tabl e Tabl e Tabl e Tabl e Tabl e Tabl e Tabl e 

### A l A 2 * 

### A 3 A 4 A5 . A 6 A 7 A 8 A 9 AI O A H A1 2 Dodg e Purg e FlowRate s 3 0 Pontia c Purg e Flo wRate s 3 1 RV P o f Tes t Fuel s .3 2 Tes t Fue l Inspections . .3 3 Baselin e Refuelin g Emissions... . ...3 4 Dodg e Refueling Emission s 3 5 Pontia c Refuelin g Emission s 3 6 Effec t o f Caniste r Size.... . 3 7 Dodg e Baselin e Regulate d Emission s 3 8 Dodg e Regulate d Emission s 3 9 Pontia c Baselin e Regulate d Emissions......... . 4 0 Pontia c Regulate d Emission s .4 1

i iP.6 9



### EXECUTIV

E SUMMAR

Y Thi s repor t present s the finding s o f th e Onboar d Con
tro l o f Refueling Emission s Projec t undertake n b yExxo n Researc h an d Engineering Co . (ERE ) unde r contrac t t o th e America n Petro
leu mInstitute . Onboard refueling contro l technolog yha s bee n successfull yapplie d t o tw o vehicles , a 198 5 Dodg e 60 0 an d a 198 4 Pontia c Parisienne , meetin g stringen t exhaus t an d evaporativ e emission s standards . Refueling emission s have bee n controlle d wit h 98+ % efficienc ywithou t a vapo r sea l in test s wit h 11. 8 RV P fue l a t 88°F .

Th e Dodg e wa s designe d a s a on e caniste r systemt o handl e bot h the evaporativ e an d refueling emissions . The Pontia c wa s designe d a s a tw o caniste r system . The productio n evaporativ e caniste r wa s retaine d t o onl yhandl e the evaporativ e emission s fro mthe carburetor . The refueling caniste r wa s designe d t o handl e bot h the refueling emission s an d th e evaporativ e emission s fro mthe tank . Th e design siz e o f the Dodg e refueling caniste r wa s 3. 5 liter s fo r a 1 4 gallo n fue l tan k whil e the the Pontia c use d a 7:5-lite r caniste r fo r a 2 5 gallo n fue l tank .

The element s o f the Onboar d systemfo r controlling re fueling emission s wer e constructe d ou t o f component s simila r t o thos e foun

d i n curren t automobil e evaporativ e contro l systems . I n bot h vehicle s th e productio n fillpip e wa s used wit h the vapo r ven t reroute d t o the Onboar d canister . Th e entir e systemwa s de

signe d fo r minimu

mpressur e drop s o tha t a mechanica l o r liqui d vapo r sea l i s no t necessary . Th e flowo f fue l int o th e tan k pro vide s enough pressur e head t o forc e the tan k vapor s int o the canister . The newvapo r ven t li.n e wa s relocate d t o remov e en traine d droplet s an d preven t spitback . Acombinatio n vapor liqui d separator , overfil l shutof f valve , an d rollove r shutof f valv e locate d betwee n the fue l tan k an d th e caniste r remove d an y remaining entraine d droplets .

Bot h Onboar d vehicle s wer e thoroughl yteste d accordin g t o a draf t procedur e propose d b yth e U . S . Environmenta l Protec
tio n Agency . Th e following conclusion s ar e draw n fro m thi s test
ing . 1 . Refueling emission s wer e controlle d wit h 98+$efficienc yunde r sever e tes t condition s using a n 11. 8 RV P gasolin e dispense d a t 88° F a t flowrate s o f 4 t o 1 1 gp mwithou t a vapo r seal . 2 . Ther e i s n o effec t on the operatio n o f a n automati c gasolin e dispensin g nozzl e an d n o spitbac k wa s observed . 3 . The contro l o f evaporativ e emission s wa s improve d t o the exten t tha t the presen t standar d o f 2 grams/tes t prescribe d fo r a 9 RV

P fue l wa s me t wit h a fue l o f 11. 8 RVP .P.7 0



### - 2

4 . Acompariso n o f the tailpip e regulate d emission s fro mth e productio n an

d th e Onboar d vehicles.show s tha t fo r the Pontia c ther e i s a numericall ysmal l bu t statisticall ysigni

ficien t increas e in HC an d N0 „ emission s bu t a numericall y larg e an

d statisticall ysignificien t decreas e i n C O emissions . The Dodg e me t th e 9 RV P tailpip e regulate d emis

sion s on a

n 11. 8 RV

P fuel . Ther e wa s a numericall ysmal l bu t statisticall ysignificien t increas e in HC an d N0 X

### emissions . Bot h the productio n an d Onboar d Pontia c me t H C an d N0 X

### stand

ard s bu t no t th

e C O standar d on the 11. 8 RV P fuel . The " Onboar d vehicl e me t th e C O standar d on the 9 RV P fuel . 5 . Th e Onboar d caniste r can b e purge d faste r than i s necessary t o restor e it s capacit yusing the productio n purg e systemfo r the productio n evaporativ e canister . Dat a i s als o presente d relating caniste r siz e t o re fueling emission s an d th e effec t o f dispensing rate . Durabilit y testing an

d diagnostic s ar e beyon d th e scop e o f th e project . However » non e o f the component s o f the Onboar d system presen t durability-problem s tha t hav e no t bee n addresse d i n curren t evaporativ e contro l systems .

Finally , fro

m a customer' s viewpoint , sinc e no vapo r sea l wa s used , vehicle s equippe d wit h th e Onboar d system shoul d no t be perceptibl ydifferen t fro m curren t productio n vehicles .P.7 1



### - 3 -

INTRODUCTIO

N Emission s o f hydrocarbo n vapor s fro mvehicle s during refueling operation s can be controlle d eithe r b yStag e I I system s a t the gasolin e dispensing facilitie s o r b ya n Onboar d charcoa l systemin the vehicl e itself . Stag e I I system s ar e in-plac e in Californi a an

d Washington , DC . Th e Onboar d System wa s demon

strate d b

yExxo n an

d Mobi l wit h fou r 197 8 vehicle s in 197 8 con tract s wit h AP I (1) . Recently , EP Aha s agai n state d thei r inten

tio n t o mak e a decisio n in 198 5 on th e issu e o f controlling re fueling emissions .

Ther e have bee n thre e majo r criticism s o f onboar d con tro l o f refueling emission s an d th e 197 8 AP I tes t program . They are : . 1 . The complexit yo f an d tes t tim

e require d fo r th

e propose d tes t procedure . 2 . The inabilit yt o contro l refueling emission s wit h gasoline s a t high RV

P whil e maintainin g contro l o f tailpip e emissions . 3 . API' s 197 8 demonstratio n vehicle s ar e no t representativ e o f today' s technology , particularl ywit h regard t o the fue l system an d emissio n contro l technology . Thi s repor t cover s the wor k performe d t o confir mthe feasibilit yo f onboar d contro l wit h moder n hig h technolog

y vehicles .

AP I Repor t No . 430 8 Oc t 197 8 "Onboar d Contro l o f Vehicl e Refuleing Emissions "P.7 2


### 4 -

RESEARC H OBJECTIVE S

Th e objective s o f thi s projec t were : 1 . T o confir

m th e feasibilit yan

d effectivenes s o f onboar d technolog

ywit h today' s hig h technolog

yvehicle s wit h moder n fue l system s on gasoline s o f high volatilit ywithou t an y debit s in exhaus t emission s o r driveability , 2 . T o determin e the feasibilit yo f the propose d EP Ates t procedur e an

d sugges t possibl e improvements ; an d 3 . T o confir

monboard' s potentia l fo r controllin g exces s evaporativ e emission s on gasoline s o f high volatility .P.7 3



### PROGRA M OUTLINE Vehicle s Two lat e mode l vehicle s representativ e o f 198 7 vehicl e technolog

ywer e equippe d wit h onboar d contro l systems . Although th e tren d o f futur e vehicle s i s toward fue l injectio n becaus e o f exhaus t emissio n contro l an d vehicl e driveability , a carburete d vehicl e represent s a wors t cas e sinc e a carbureto r i s les s flex

ibl e in it s fue l metering . Therefore , one carburete d vehicl e an d on e throttl e bod

yfue l injecte d (TBI ) vehicl e wer e chose n (se e Tabl e 1) . Base d on preliminaryEP Adata , the Pontiac , wit h a larg e tan

k an d a shor t rea r fillpipe , wil l probabl yhav e th e highes t leve l o f refueling emissions . Tabl e 1 TES T VEHICLE S Vehicl e No . 1 Vehicl e No . 2 Mak e Dodg e Pontia c Mode l 60 0 Parisienn e Yea r 198 5 198 4 Cylinder s 4 8 Displacemen t 2. 2 1 5. 0 1 Ga s Tan k 1 4 gal . 2 5 gal . Fil l Poin t Sid e Rea r Fue l SystemTB I 4 bb l Feedbac kFIGUR E 1 

# PRINCIPA L ELEMENT S O F ENHANCE D ON-BOAR D SYSTE M

. Standar d Fillpip e Wit h Ven t Reroute d t o Canniste r Rollove r Shutof f Overfill/Shutof f Entraine d Liqui d Separato r Purge d H C Vapor s T o Engin e

H C Vapor s • i



## Enlarge d Charcoa l Canniste r

### - 8 -

•



### » Onboar d System

Design Overal l Design The principa l element s o f a n enhance d onboar d systemt o contro l refueling an d evaporativ e emission s ar e show n in Figur e 1 . The standard fillpip e i s used wit h the vapo r ven t reroute d t o the onboard canister . Th e ne wvapo r ven t i s locate d opposit e t o th

e fillpip e in orde r t o remove entraine d droplets . T o reduc e entraine d droplet s further , a vapor-liqui d separato r i s positione d betwee n th e tan k an d th e canister . Th e ne woversize d vapo r lin e lead s t o the charcoa l caniste r locate d eithe r in th e engin e compartmen t o r th e trunk . The entir e systemi s designe d fo r minimu

mpressur e drop s o tha t a mechanica l o r liqui d (such a s a "J " tube ) vapo r sea l i s no t necessary . The systemi s discusse d furthe r in the following paragraphs . Charcoa l Caniste r Design 'Th e design o f the charcoa l caniste r wa s base d on ERE' s 197 8 work . I t i s a two-pas s meta l containe r wit h a close d bottom an d a to p ven t a s show

n in Figur e 2 . Th e canister s have a n L/ D rati o o f 2.5 . Thi s wa s estimate d in the 197 8 stud yt o provid e an optima l length-to-diamete r ratio : to o shor t a pat h lengt h woul d resul t in a los s o f working capacit yan d to o lon

g a pat h lengt h woul d caus e a hig

h pressur e drop acros s th e caniste r during re fueling . The Dodg e wa s designe d a s a on e caniste r system . Th e productio n evaporativ e caniste r wa s replace d b ythe refueling canister . The refueling caniste r wa s designe d t o handl e no t onl y the refueling emission s bu t als o th e diurna l an d ho t soa

k evapo rativ e emissions . The Pontia c wa s designe d a s a two caniste r system . Thi s wa s b

ychoic e i.e. , t o demonstrat e the effectivenes s o f bot h systems . I t coul d hav e bee n designe d a s a on e caniste r syste mjus t a s easily . Th e productio n evaporativ e caniste r wa s retaine d t o handl e th e evaporativ e emission s fro mthe carburetor . The refueling caniste r handle d al l the evaporativ e emission s fro m th e fue l tank .

Th e canister s wer e loade d wit h 6x1 6 mes h Calgo n BPLF 3 activate d charcoal . Thi s carbo n wa s use d in the 197 8 stud yan d i s currentl ybeing used in man yevaporativ e contro l canisters . Calgo n BPL-F 3 ha s a fres h butan e adsorptio n capacit yo f 6 8 grams / lite r wit h a

n apparen t densit yo f 0.3 5 grams/cc . I n orde r t o ac coun t fo r possibl e degradatio n in the initia l working capacit y wit h age , increase d loading du e t o ai r entrainment , an d t o pro vid e a safet ymargin , 3 0 grams/lite r wa s chose n a s th e design working capacity .

I n th e 197 8 study , a working capacit yo f 2 5 t o 3 5 gram s butan e wa s used . Therefore , base d on fue l tan k volume an

d th e baselin e refueling emission s fo r the 1 2 RV P fuel , two canister s wer e constructed , a nomina l 3. 5 liter s (1 ) an d a nomina l 7. 5 L ,P.7 6



## - 7 - FIGURE i

CHARCOA L CANISTE R 

### PURG E CONNECTIO N

WIR E MES H
REFUELIN G PURG E VAPOR S VAPOR S
FUE L TAN K CONNECTIO N
META L DIVIDE R PERFORATED META L

GLAS S WOO L VEN T

GLASSWOO L

META L DIVIDE R

INSULATING
SHEE T

CHARCOA LP.7 7


### 9 - 

# EifiUBE J r 

## COMBINATIO N VALV E

.4 - 1.0 . ROLLOVE RSHUTOFF
1/2 - OlA

S S BALL

1 1/9' OVERFIL L SHUTOFF



## s A*A»ATA*A*A*AVATATA*ATA*ATATA»ATA*A*A -

•A*ATA*A*ATANTAN.TATA*A*ATA*AT*VATAT»T . A^ATATATATAVATA^ATATATATATATAVATATAn , 'A ; yAVA»A^ATATATA^A , »A , »iTA^ATA»A»A'A'»ATA''A T ATATAVATATATATAVATA^AVATATAVATATATAVATA ' .TATAVAVAVAVATAVA^ATA^ATA^ATATATATATATAT . A^ATAVATA»ATA»ATA'»ATA^AVAWAVATAVAV_r »

>A, »ATATATA^A'*A'»A^ATATA, »A'»A'»A'»A, rA'AVAVA ; A^^ATA'UTA''A , »A^ATATATATA%,TA''AnTA'»ATA : A*ATA*A*A*A*A*A*A*ATATA'rA*A»A*ATA'»A'»A'*A : .TAVAWATATAWAWAWAWAWAWA'VA''' . A^ATATA'» ,A'rATATATATATATA'»ATA''A'»ATATA' l rA^A AVATAVATATAVATAVATATAVATATAVAVATAVATATA '

.•A^AVAVATA^A^A'»ATATATATATATATATATATATAT ;
A^A'A»A''A^A'A'A''A'TA^ATA'A'»A'»A 1 UTA^AVA^A ' S. S MES H

VAPO RLIQUI D SEPARATO

R



## KXXXX)(X)(X)Q()()QQ()QQ(X) C 

# iliilllllll 1

### 1 0 -

fo r the 1 4 gallo n Dodg e an d the 2 5 gallo n Pontia c respectively . I n addition , a 5 1 caniste r used in the 197 8 stud yrefueling stud yan d i n othe r ER E program s wa s use d i n bot h th e Dodg e an d th e Pontia c t o investigat e th e effec t o f caniste r size . Vapor-Liqui d .Separato r an d Vapo r Line s Th e vapo r lin e fro

mthe tan

k t o the caniste r wa s 3/ 4 inc h I.D . Buna NWeatherhea d H1001 2 fue l lin e hose . Th e diamete r wa s chose n t o minimiz e the pressur e drop i n the system . Th e pro ductio n vapo r line fro mth e tan k t o th e evaporativ e caniste r wa s plugged . The ne w3/ 4 inch vapo r lin e remaine d ope n t o the tan k an d caniste r during al l operations .

Avapor-liqui d separato r wa s place d ahead o f the can iste r i n the vapo r lin e a t the leve l o f th e fillpipe . Prelim

inar yexperiment s indicate d tha t som e entraine d droplet s coul d trave l u

p the vapo r line . The vapor-liqui d separato r insure s tha t onl yvapo r reache s th e charcoa l canister . (An yliqui d absorbe d on the charcoa l woul d reduc e it s effectiveness. ) Mos t o f th e dat a was ; collecte d using a vapor-liqui d separato r constructe d fro ma pin t can fille d wit h stee l mesh . Towar d the en d o f the project , a combinatio n vapor-liqui d separator , rollove r valve , an d overfil l valv e wa s constructe d a s show n i n Figur e 3

- Th e volume o f the vapor-liqui d separato r wa s one pint . Th e rollove r valv e wa s simpl ya 1/ 2 inch stee l ball . The overfil l valv e wa s a floa t constructe d fro m a tan k gag e floa t fro

m a Genera l Motor s fue l pick-u

p assembly . Crud e benc h test s indicate d tha t th e rollove r bal l valv e hel d in the 18 0 degre e position .

The lin e t o th

e caniste r wa s place d in the vapo r dome o f the tank . I n th e Dodge , sinc e th e vapo r dome extend s acros s the entir e rea r portio n o f the tank , th e lin e t o the caniste r wa s place d on the opposit e sid e o f th e tan k fro mthe fillpip e t o reduc e entraine d droplets . I n the Pontiac , the productio n fillpip e direct s th e liqui d ont o a secondarybaffl e protectin g the sending unit . T o reduc e entraine d droplet s create d b ythi s baffle , the secondarybaffl e wa s removed , the fillpip e extende d an d aime d downwar d awa yfro mthe sending unit . Th e fillpip e therefor e became a submerge d fil l a t abou t mid-fill . I n th e Dodge , the fillpip e become s submerge d a t abou t 95$ . Th e vapo r lin e t o the caniste r wa s place d i n the vapo r dom e whic h als o house d th

e sending unit . Fillnec k Vapo r Sea l Th e fillpipe s an

d fillneck s wit h th e lea d nozzl e restricto r fo r bot h vehicle s wer e standar d productio n withou t an y nozzl e o r fillpip e seals . However , th e productio n ven t line s wer e plugge d insid e the tan k bu t remaine d in place . Th e newvapo r line s t o the caniste r provide d th e exi t rout e fo r the vapor s generate d during refueling . Wit h the lowpressur e drop design o f the caniste r an

d vapo r line , n o sea l a t the fillnec k wa s needed . Th e flowo f fue l int o th e tan k provide s enough pressur eP.7 9



### - 1 1
hea d t o forc e th

e tan k vapor s int o th

e canister . In addition , ai r i s aspirate d int o the tan k slightly , increasing th e caniste r loading an

d preventing an

yvapo r releas e ou t th e fillpipe . Purg e System The canister s ar e purge d wit h ai r in th e directio n opposit e t o the adsorptio n o f hydrocarbon s (countercurrent) . Th e purg e contro l system , including purg e contro l valves , purg e contro l orifice , purg e pipes , et c , wer e standar d productio n fo r bot h vehicles . Fo r th e Dodge , the purg e contro l valv e i s buil t int o the productio n evaporativ e canister . I t wa s remove d fro mth e evaporativ e caniste r an d installe d inlin e t o th e refueling caniste r whic h wa s locate d in the engin e compartment . I n th e Pontiac , a te e wit h balancing orifice s wa s place d in th e norma l productio n purg e line . The productio n vapo r lin e fro mthe tan

k t o th e productio n evaporativ e caniste r wa s use d a s the purg e lin e t o the refueling caniste r mounte d in the trunk .

.A s can be see n in Table s A 1 an d A2 , the purg e rate s fo r the Dodg e average d 1. 4 1p man d fo r the Pontia c 8. 8 1p m ove r on e LA- 4 driving cycl e wit h 7. 8 1p m purging th

e refueling caniste r an d 1. 0 1p

mpurging the productio n EC S canister . Th e Dodg e TB I fue l deliverysystem operate d wel l belo wwher e additiona l purg e woul d caus e los s o f contro l o f air-fue l ratio . A t 5 0 mph , th e purg e rat e wa s 5. 3 1pm . Los s o f contro l occurre d a t 16. 1 1p mo f pur e butane . Thi s wa s no t the cas e fo r the carburete d Pontiac . Los s o f contro l o f th e air-fue l rati o occurre d a t 1 8 1p mo f pur e butan e an

d the purg e rat e i s 1 8 1p ma t 5 0 mph . Wit h a saturate d canister , the purg e strea minitiall ywil l hav e a high concen tratio n o f hydrocarbons . An ylos s o f contro l in the air-fue l rati o coul d the n resul t in increase d exhaus t emissions . Tes t Procedur e Th e tes t procedur e use d t o measur e th e refueling an d tailpip e emission s wa s base d on the draf t procedur e presente d b y the EP Aa t thei r Oct . 17 , 198 4 worksho p on "ONBOARD CONTRO L O F REFUELIN

G EMISSIONS" , "TES T PROCEDUR E DEVELOPMEN T AN D PRELIMINAR

Y BASELINE TES T RESULTS " hel d in An n Arbor , Michigan . Thi s draf t procedur e utilize s th e basi c SHE D tes t equipmen t fo r measurin g H C evaporativ e emissions . The refueling i s conducte d insid e the SHE D unde r specifie d tes t conditions .

The tes t procedur e i s relativel ystraigh t forward . The tes t fue l i s heate d t o tes t temperatur e in a Horib a fue l condi

tioning cart . The fue l i s the n recirculate d through th e dispens

in g pump , Tokhei mMode l 785-MC-PR , u p t o the SHE D wal l an d bac k t o the Horib a fue l cart . The vehicle' s tan k i s heate d b

ya blan

ke t t o tes t temperature . Whe n the tes t condition s hav e stabil

ized , the OP W automati c nozzl e i s place d i n the fillpip e on the high settin g afte r dispensin g 3 gallon s o f heate d fue l int o a drum . The SHE D doo r i s close d an d a backgroun

d H C reading i s take n forma t leas t thre e minutes . Afte r the refueling , a stabil

-P.8 0 

### -1 2 -
i.ze d HC reading wa s taken . I t normall ytook betwee n 3 t o 4 min

ute s eve n wit h a

n extr a explosio n proo f fa n providing additiona l ai r circulation . Th e FI D H C reading wa s continuousl yrecorded . Th e differenc e betwee n th e two H C reading s determine d the refuel

in g emissions . Sinc e n o mechanica l sea l wa s use d on th e fill

pipe , the conservativ e approac h o f no t tim e extrapolatin g th

e background wa s used . Thi s als o counte d the emission s fro mthe nozzl e jus t being in th e fillpipe . The specifie d tes t condition s ar e give n i n Tabl e 2 below . Tabl e 2
TES T PARAMETER S Paramete r EP A ERE EPA(new ) Dispensed,Fue l Temp. , de g F 88+/- 2 88+/- 1 88+/- 2 Temp . Differential , de g F (Tan k - Dispensed ) max . + 5 averag e 0 + 2 t o + 5 rang e +/- 2
Leve l Prio r t o Fill , %tan k 1 0 1 0 1 0 Filling Rate , gp

m 7 t o 1 1 6 t o 10. 5 8 t o 1 0 Fill , %tan

k 1 0 t o 9 5 1 0 t o 9 5 1 0 t o auto
shutof f The placemen t o f the refueling emission s tes t i n the curren t Federa l Tes t Procedur e (FTP ) i s show n in Figur e 4 an

d outline d below . 1 . Th e tes t begin s wit h th e refueling capacit ytest . I n thi s test , the vehicl e i s refuele d insid e the SHE D fro m 10 $ o f tan k volume t o 95 $ o f tan k volume . Th e targe t parameter s ar e 88° F dispense d fue l temperatur e an d a 0° F delt a T . Sinc e preconditionin g o f th e caniste r wa s no t specifie d b yEP Abu t onl ystate d a s "EP

Aassume s vehicle s wil l b e drive n i n a representativ e manne r unti l (the ) fue l leve l reache s 1 0 percent" , th

e caniste r wa s purge d on a benc h ri g unti l th e weigh t wa s such tha t breakthrough woul d occu r during the secon d refueling . Thi s wa s no t a dr ycaniste r condition . A dr yconditio n woul d have resulte d in requiring thre e t o fou r refueling s fo r breakthrough t o occu r a t 1 0 gpm . Saturatio n woul d requir e more . Thi s resulte d in saving s in bot h time an d tes t fuel .- 1 3 -


### Finur e 4 P.8 1

Invlroitnw-nta l Protectio n Agency 9M.130-7 I

ru n DRAI N t m i 

# I

DVN O miCONOlDONIN C 

# I

CCH O SOA KPARKIN G

I I I I I I I I I I I I I I I I L . r * i i I 

# I

FUtllN G

• ORAI N
•40 % tU 

# I
DIURNA l MIA t IUII D

•MA Trun- 1 HOU R •40l4* f IVAP . US T NO TRt O OIURNA l

INClOSUR t TIS t 

# T333I
COI D STAR

Tf XHAUS

TTIST 

# } } I HOU R MA X

1 MIN . MAX . Refueling Capacit yTes t

Saturat e caniste r (Tw o ful l refuelines ; 1s t on e i s 95%fil l test )

> » ? 3 6 HOUR S (n o mo. , lo * dittrlt ) Disconnec t caniste r



### Reconnec t

IVA THS t NO T •IRFORMf D H C RUNNIN G

IOSSIS-A S RI O 

# } 0- 1 HOU R 

# i r
HOTSTAR

TI XHAUS

TTIS 1 I I I I I I I I I I 

# I
HO I SOA K INCIOSUR I TtST

CNO 

# } } 1 0 MI N

7 MIN . MA X

Figur e I/ I i s "i n SIOUINC I Refuelin g Purg e Tes t Sequentia l IA-4 c end

ho t sock s (Drive dow

n t o 10? ) 30 % fil l tes t

53-124 O-li 

### 50 3

### 1 4 -

I f onl yrefueling emission s wer e t o be determined , the tes t ended here , otherwis e i t continued . 2 . Afte r the capacit ytest , additiona l refueling s wer e conducte d unti l breakthrough occurred . Breakthrough wa s determine d b y observing th e obviou s shar p increas e in the SHE D HC concentratio n v s tim e recorde r trace . Th e refueling the n continue d unti l th

e tan k wa s full . Thes e additiona l refueling s wer e conducte d fro ma n empt ytank . Th e SHE D HC concentratio n a t th e en d wa s usuall ygreate r than 10 0 pp mC 6 o r abou t 1. 3 gram s pe r gallo n (g/g) . EPA' s criterio n o f a 3 fol d chang e i n H

C concentratio n t o indicat e breakthrough i s unrealistic . Th e hydrocarbo n concentratio n increasing smoothl yfro

ma backgroun

d o f 1 pp

mt o a fina l valu e o f 3 pp m doe s no t indicat e breakthrough . Th e hydrocarbo n concentra
tio n increasing fro ma backgroun

d o f 1 0 pp

m t o a fina l valu e o f 3 0 pp

m ma yindicat e breakthrough . I t i s ou r experienc e tha t breakthrough i s indicate d b ya n obviou s sharp increas e i n concentratio n afte r a perio d o f onl yminima l increase . A recorde r i s ver

yhelpful . 3 . The norma l FT P test s fo r diurnal , tailpipe , an d ho t soak emission s wer e the n performe d including the overnigh t soak . Th e refueling caniste r wa s disconnecte d during the filling an d draining o f th

e 40 $ tan

k fil l require d fo r the norma l FTP . I t wa s connecte d fo r th e soak an

d FTP . 4 . The refueling purg e tes t wa s the n conducted . Thi s consiste d o f driving sequentia l LA-4' s an d ho t soak s unti l the tan k volume wa s 10$ . The ho t soak fo r th e Dodg e wa s on e hou r an d fo r th e Pontia c 1 0 minutes . Sinc e the running tim e fo r the Dodg e wa s abou t 1 8 hours , i t require d tw o shif t a da

y operation . Th e vehicl e soake d wit h the caniste r plugge d fo r the third shift . Th e drivedow n wa s conducte d in the Controlle d Temperatur e Roo mwit h prope r ai r flo wove r the vehicle . Withou t prope r ai r flowa s on a norma l Clayto n dynamometer , exces s heating o f the fue l tan k coul d occu r an

d bia s the results . The tan k temperature s on bot h vehicle s matche d thos e obtaine d on th e road . Afte r reaching 10 $ o f tan k volume , th

e refueling emission s fo r a a 10 $ t o 40 $ refueling wer e measured .

I n Au g 22 , 1985 , EP

Apublishe d a revise d draf t tes t procedur e fo r th

e measuremen t o f refueling emissions . Th e mai n difference s fro mthe abov e draf t tes t procedur e wa s the chang e in the refueling capacit ytes t (ite m1 ) fro

m1 0 t o 95 $ t o 10 $ t o auto-shutof f o f th e automati c nozzl e wit h a minimu m o f 85 $ fill . Therefore , a t th e en d o f thi s study , a limite d numbe r o f test s wer e conducte d t o auto-shutof f o f the nozzle .

Th e test s wer e conducte d in a randomize d orde r t o reduc e an

ytes t orde r effect .P.8 3



### - 1 5

Fuel s Sinc e previou s studie s (2,3 ) hav e show n tha t refueling emission s correlat e wit h onl yth e RV P o f the tes t fue l an d no t an yD-8 6 distillatio n points , the tes t fuel s fo r thi s progra m wer e blend s o f Indolen e an d butane . Two differen t batche s o f Indolen e wer e used . Th e inspection s o f the tes t fuel s take n fro m the fue l conditioning car t jus t befor e the test s ar e give n in Table s A 3 an

d A4 , an

d the RV

P o f the tw

o blend s i s summarize d below .

avg . std . dev.. . N 9

Batc h 1 8.8 7 0.2 4 2 7 RV

P RV P Batc h 2 9.5 5 0.1 8 1 4 Tabl e 3 o f Tes t Fuel s

10. 5 RV P Batc h 1 Batc h 10.4 5 10.9 4 0.1 9 0.2 4 1 8 1 1 2 1 2 RV P Batc h IBatc h 2 11.6 3 11.8 3 0.2 0 0.3 0 2 5 2 4

2 "A n Experimenta l Stud yo f Vehicl e Refueling Emissions " Hochhause r an

d Campion , SAE Pape r No . 760307 , Feb . 197 6 3 " AStud

yo f Variable s tha t Effec t the Amoun t o f Vapo r Emitte d During the Refueling o f Automobiles " AP I Repor t No . CEA-21 , May,,197 5P.8 4 

### 1 6 -

RESULT S Refueling Emission s

98+ $ contro l o f refueling emission s wa s achieve d wit h bot h th e one an

d tw o caniste r onboar d systems . The dat a i s summarize d in Figure s 5 an d 6 . The baselin e refueling emission s ar e give n i n Tabl e A5 , whil e th e controlle d refueling emission s ar e give n in Table s A 6 an d A7 . O

n bot h th

e 9 an d 10. 5 RV

P fuels , the Dodg e average d 0.0 4 g/ g o r 99.3 $ control . Th e Pontia c average d 0.0 7 g/ g o r 98.9 $ contro l on th e 9 RV P fue l an

d 0.1 0 g/ g o r 98.8 $ contro l on th e 10. 5 RV P fuel . Sinc e the degre e o f contro l wit h th

e 9 an d 10. 5 RV

P fuel s wa s hig

h an d the variatio n betwee n run s approache d th e limit s o f measurement , mor e run s wer e conducte d wit h the 1 2 RV P fuel . Wit h the 1 2 RV P fuel , th e Dodg e average d 0.0 9 g/ g o r 98.8 $ contro l an d the Pontia c average d 0.1 6 g/ g o r 98.4 $ control . (Th e percen t contro l i s base d on baselin e refueling emission s an d no t on the loading on the caniste r whic h wa s higher. ) Effec t of : 

### Auto-Shutof f

I n the lates t versio n o f the tes t procedure , EP A change d the refueling fro m10 $ t o 95 $ t o 10 $ t o auto-shutof f o f the nozzle . A s can be see n in Tabl e 4 , ther e i s n o effec t o f fueling t o autoshu t of f wit h bot h vehicles . Th e Dodg e average d 0.0 9 g/ g whil e th

e Pontia c average d 0.1 8 g/g . N o spitbac k wa s notice d in the eigh t plu s runs . Spitbac k woul d no t be expecte d i f spitbac k i s cause d b ya temporaryhighe r tha n norma l pressur e in the fue l tan k a t th e en

d o f th e fill . Thi s temporar yhigh pressur e coul d b e cause d b y covering th

e vapo r exi t line-wit h liqui d gasolin e a t the en d o f th e fill . Withou t a lowpressur e drop exi t path , th e rising liqui d leve l an

d th e forc e o f the incoming liqui d woul d increas e the pressur e in th

e tank . The n whe n th e nozzl e i s shu t off , th e pressur e in the tan k i s relieve d b

y"spitting " bac k ou t the fillpipe . Th e vapo r lin e coul d be covere d wit h liqui d i f i t exite d th e tan

k on th e sid e o f the tan

k nea r th e ful l tank liqui d leve l o r insid e the fillpip e a s wit h th e Pontiac . Sinc e the vapo r lin e in bot h onboar d vehicle s exi t th e tan k fro m the to p o f the vapo r dome , the vapo r lin e canno t become covere d wit h fuel . The vapo r lin e t o the caniste r wa s locate d in the dome , therefore , t o bot h reduc e entraine d droplet s an d t o reduc e an

y probabilit yo f spitbac k occurring .

I t shoul d b e mentione d tha t i t wa s possibl e t o fil l the productio n Pontiac' s tan k wit h 2 9 gallon s o r 116 $ a t auto-shutoff . Therefore , the 113 $ show n i n Tabl e 4 wa s expected .

## Figur e 5

^ 

# O * 

# nndge

600 Refueling

Emissions 10- 

## 9-

m 

## 8- 7- 6- 

# 6
4 - 

## 3- 2- 1 0 

# EZ2

Production CZ I On-Board

Control

•



# 12.0

I o o u .

## Flgur * 6



# Pontiac Refueling

Emissions 10- 9- 8- 7- 6- 

# V7Z\

Production I— | On-Board

Control

CO I

## 0671-T-GS M TABL E a FFFFt T O F AIIT

O SHUT-OF F 1 2 RV P CAR . 4 4 

## 1 0 - 95 Z 

# HIL L fi/G. 

# 0.0 9 98. 8 7

9 99 

# 10 0 10 0 10 0 9 7 Z 

# z z z z z ML 

# 0.0 1 0.0 4 0.0 3 0.3 5 0.0 8 0.0 9 0.1 3 99. 9

99. 5 99. 6 95. 6 99. 0 

# 39* & 98. 9 

# 1. 6 JD 

# 8 8 8 8 89 88 89 8 8 AVERAG E S X 

# J L

0

- 1 

# 0 0

- 2

- 1 

# £H L

8. 2 9. 5 9. 6 10. 8 

# 9. 9

I


# 10 3 0.1 6 98. 4 

# 11 3 11 3 Z 

# z 0.1 5 

# JL2 & 98. 5 

# SL1 8

8 8 7 

# 0

1 

# 10. 1 10. 2 0.1 8 0.0 4 98. 2



# 0. 4 AVERAG

E S X

lo o * HP.8 8 

## 2 0

Effec t o f Rollover/Overfil l Valve s

As can be see n i n Tabl e 5 , the additio n o f the combinatio n vapor-liqui d -separator , rollove r valve , an d overfil l valv e di d no t adversel yaffec t the refueling emission s o f the Dodge . Withou t th

e combinatio n valv e th e refueling emission s average d 0.0 9 gpg an d wit h th

e valv e 0.0 2 gpg . Sinc e the combinatio n valv e wa s designe d fo r minimu mpressur e drop , thi s wa s expected . I t als o di d no t affec t automati c nozzl e shutoff .

REFUELIN

G
Withou t GP G $ Tabl e 5

EMISSION S WIT H COMBINATIONVALV E (1 0 t o 95$ )

GP G 0.0 1 0.0 3 Wit h

$ T

D DT 99. 8 8 8 4 99. 6 8 9 - 1 GPM 10. 0 9. 7 averag e 0.0 9 98. 8 0.0 2 99. 7 Effec t o f Caniste r Siz e

The effec t o f caniste r siz e on the refueling emission s wa s briefl ystudie d o n bot h vehicles . The dat a i s presente d i n Tabl e A 8 an

d i s summarize d in Figur e 7 . A s can b e see n fro m Figur e 7 , an

d a s i s expected; , the refueling emission s ma yb e a functio n o f th

e siz e o f the caniste r expresse d a s liter s o f charcoa l pe r gallo n o f tan k volume . The slightl yoversize d 5 1 . caniste r fo r th

e Dodge , 0.3 6 liter s o f charcoa l pe r gallo n o f tan k volume gav e 98.8 $ o r 0.0 9 gpg . Th e slightl yundersize d 5 1 caniste r fo r th

e Pontiac , 0.2 0 1/gal , average d 96.9 $ o r 0.3 0 gp g although i t varie d fro m94.5 $ t o 98.2$ . Considering the limite d numbe r o f tests , an d th e variatio n in result s experience d (99.8 $ t o 97.7 $ fo r th e Dodge) , car e shoul d be take n in applying thi s relationship .

Ther e i s a trade-of f betwee n caniste r size , cost , an d operability . Th e mechanica l sea l approac h ma yallo wthe us e o f a smalle r caniste r bu t add s th e complexit yan

d expens e o f the mechanica l sea l an

d pressur e relief . The liqui d sea l i s les s complicate d an

d expensiv e than the mechanica l sea l bu t require s a slightl ylarge r canister . Th e no sea l approac h doe s requir e a slightl ylarge r caniste r bu t ha s no othe r additiona l cost . I t als o ha s the advantag e o f no t changing th e customer' s perceptio n o f refueling .

## FIGUR E 7



# Effect of Canister

Size on Refueling

Emissions 12 RVP

0.3 A c

. o c* v 

# E

C O 

## C



# . 2 <0 

## jn 

# D ) O. H 0. 2 

# H

0.0- f I r o



# —r ~ 0. 2 —r ~

0. 3 —r "

0. 4 

# Liters of Charcoal

per Gallon Tank Volume

I o o (O

### TABL E 6
REGULATE D TAILPIP E EMISSION S

» betwee nnumber s denote s statisticall y significan t at 90 $ confidenc e leve l D o Ig o Base 1 

### In e Controlle d
Pon t1a c Baselin e Controlle d 9 RV P

2.28 5 2.37 7

3.42 4 2.73 2 C0^g/ m

10. 5 RV P

2.23 5 2.82 3

» H.33 3 » « 

### * 3.57 0 1 2 RV

P

2.58 0 3.20 0

5.39 8 * 

### 3-64 7 9 RV

P

0.12 6 I I 

### 0.15 7

0.23 1 0.25 4 HC , g/ m

10. 5 RV

P

0.10 2 « 

### 0.16 7

0.23 1 * » 

### 0.30 2 1 2 RV

P

0.13 4 « 

### 0.15 9

0.28 2 » 

### 0.335 * 9 RV

P

0.61 4 « 

### 0.70 3

0.51 2 tt 

### 0.57 8 N0x t

### g/ m

10. 5 RV

P

0.60 1 tt 

### 0.68 6

0.51 1 I I 

### 0.65 2 1 2 ftVP

0.67 2 0.71 1

0.48 0 « 

### 0.64 4 i

r o r o iP.9 1 

### 2 3 -
Tailpip e Regulate d Emission s

Th e dat a on th

e regulate d tailpip e emission s i s summarize d i n Tabl e 6 . Mor e detaile d dat a i s give n in Table s A9 , A10 , A11 , an

d A12 . Th e Dodg e me t the 9 RV P tailpip e regulate d emission s on a 11. 8 RV P fuel . Bot h th

e productio n an

d Onboar d Pontia c me t HC an

d N0 X

### standard s bu t no t the C O standar d o n the 11. 8 RV P fuel . Th e Onboar d vehicl e me t the C O standar d on the 9 RV P fuel . A s show

n in Tabl e 6 , ther e ar e varying response s t o RV P an d t o the additio n o f the refueling canister . Th e tailpip e emission s o f bot h the productio n an d modifie d Dodg e exhibite d littl e respons e t o RVP . Comparing the productio n vehicl e an d the onboar d vehicle , ther e i s a numericall ysmal l bu t statisticall y significien t increas e i n H C an d N0 X

### emission s (a t th e 90 $ confidenc e level) . C O emission s had to o muc h variatio n t o be statisticall ysignificient . Th e Pontia c wa s different . The C O an d H C tailpip e emission s o f bot h the productio n an d modifie d Pontia c exhibite d a respons e t o RVP . Th e C O emission s increas e wit h increasing RVP . However , the level s fo r the onboar d Pontia c ar e lower . . Comparing the productio n vehicl e an d the onboar d vehicle , ther e i s a numericall ysmal l bu t statisticall y significan t increas e i n H C an d NO „ emission s bu t a larg e an d statisticall ysignificien t DECREAS E i n C O emissions .

Th e varying respons e t o RV P probabl yreflect s the differen t fue l systems : throttl e bod yfue l injectio n v s carburetion . I n othe r AP I sponsore d studie s (4) , fue l injecte d vehicle s exhibite d les s respons e t o RV P than carburete d vehicles . The decreas e i n C O fo r the Pontia c wit h th e onboar d caniste r reflect s the increase d HC adsorptio n capabilit ya s wil l be see n late r in the evaporativ e emissions . At thi s time , n o reaso n i s know n fo r th

e increase d N0 X

### emissions . N o attemp t wa s mad e t o modif ythe purg e schedule s sinc e thi s woul d requir e reprogramin g the contro l "chip" . Sinc e the productio n purg e rat e di d adequatel ypurg e the canister , i t wa s no t changed . I t ma ybe possibl e t o obtai n bette r emission s wit h the purg e logi c optimize d fo r the large r canisters , especiall ywit h the Pontiac . A s discusse d earlier , the purg e strea mi n the Pontiac , i f al l hydrocarbons , woul d resul t i n a los s o f air-fue l rati o control .

AP I Repor t No . 440 6 Apri l 198 5 " Stud yo f Factor s Influencing Evaporativ e Emission s Fro m In-Us e Automobiles "

## Figur e 8



# Effect of RVP on Evaporative

Emissions for Production

and On-Board

Vehicles 12-t
tn 

# E

V I 

## C in 

# I 

# ' 

# I*
U j 

# 10 - 8- 6- 

# Legend GS 9 On-Board CZ ) Production

Dodge Pontiac 9 RVP 

# JB Q

Ooaae r o



# \STANDARD\

_ 

# Dodge Pontiac 10.5 RVP Dodge

Pontiac 12 RVP 

# }P.9 3

0

j

r *

IJ JTABL CO z olt c n C O 1— 1 

# 5

>
< c e O < u r H

tt3

o

I • 1 < c J - 2 5 -

> x r v o o s ir * oo

. * C M C M O «- H
0 . c e i n o

r » v © o o o <- 4

> 0 0 v O o e x r * c o 

## I o vdo '

> * * c e C M C M

C M C M 

## ^ d d

J C C t - o 

## S ". 

## d o o fc» ^ 0 a. > v O iT i o g rt * m 

### 1 o v

### d d .
0 . * > C

M x r 0 - r o vO C M C

M O r- l 1 - cu

« if vr o £ o o 3 O

— . r- l O Ou

t : > r g - - 0C | r o iT*

• 

### 1 < H 

### o o

zz c a; ! - : ~ T3 | « T

J c ! * •

o o

. . C M *" • *

v O * X T

m C M t - v O ••

r H ^

CM t - ir» » o v

. . o o O CO t o * 0 0

. . o o

CM v O v O O v

. • o o

o o r o x r » t — ••

- H O r H *
t> - O v

. . r o o

r - V O *+ m v O

. •rt O

C ~
. , 1 r-

«• • 

# r ! 

# i E c l n -c p ! r e O •

«r \ o
C O Ai c r e C J v . C 6 0 v 4 C 4 > >
r H

• r - e n re
C O © o c 0 ) • o «P.9 4



### - 2 6 Evaporativ e Emission s

The dat a o

n th e evaporativ e emission s i s summarize d i n Figur e 8 an

d Tabl e 7 . Mor e detaile d dat a i s give n i n Table s A9 , A10 , A11 , an

d an d A12 . A s show

n in Tabl e 7 , ther e ar e varying response s t o RV P an d t o th e additio n o f th e refueling caniste r bu t th

e additio n brough t bot h vehicle s int o complianc e wit h a 2 g/ T targe t on the 1 2 RV P fuel . O

n the productio n vehicle s designe d fo r 9 RVP , th e Dodg e wa s highe r than 2 g/ T o n the 1 2 RV

P fue l an

d the Pontia c wa s highe r on th e 10. 5 RV P fuel ; Thi s demonstrate s th e abilit yo f the onboar d system t o contro l exces s evaporativ e emissions .

Fo r bot h vehicles , the additio n o f th e refueling caniste r decrease d th e evaporativ e emission s (statisticall y significan t at 90$) . Although th e ho t soa

k emission s fo r bot h vehicle s tended t o hav e a a numericall ysmal l bu t statisticall y significan t increase , thi s wa s overwhelme d b yth e larg e decreas e in the diurna l evaporativ e emissions .

• The productio n vehicle s exhibite d a strong respons e t o RVP . Th e onboar d vehicle s di d not . Thi s i s t o be expecte d whe n the caniste r ha s enoug h capacity . An

yRV P effec t shoul d appea r onl ywhe n breakthrough occurs . Caniste r Purg e Drivedow n The las t portio n o f th e draf t tes t procedur e i s the refueling purg e test . Th e averag e caniste r performanc e during the drivedow

n i s give n in Figure s 9 an d 10 . Th e dat a indicat e tha t i f th

e purg e systemca

n remov e enough hydrocarbon s t o handl e the diurnal , the n i t wil l b e abl e t o handl e the 1 0 t o 40 $ refueling lon

g befor e the 30 $ fue l i s consumed . B ycalculation , i t take s 1 2 t o 1 5 LA-4' s t o consume 30 $ o f th e tan k capacity . B

y 3 t o 4 LA-4's , th

e productio n purg e systemha s remove d enough hydrocarbon s t o adsorb th e 30 $ refueling emissions . Th e Pontia c wit h th e caniste r close r t o th e tan k in the trun k ha s highe r loading s during the overnigh t soak an d diurna l test s (se e Figure s 9 an d 10) . Th e Dodg e wit h the caniste r i n th e engin e compartmen t ha d muc h lowe r loading s taking the smalle r fue l tan

k int o account . I t i s fel t tha t furthe r gain s coul d be mad e wit h th

e Pontia c i f th

e vehicl e wer e converte d t o a on e caniste r system . Effec t o f Dispensing FlowRat e

The refueling emission s o f the Dodg e improve d wit h increasing fue l dispensing rate . A s the flowrat e increase d b y on e gpm , the refueling emission s decrease d 0.0 3 gpg (97 $ confidence-1 2 RV

P fue l only) . Th e Pontia c showe d n o dependenc e o f the refueling emission s wit h fue l dispensing rate .FIGUR E 9



## 100 

# E o > o i . 

# o X I < 

## C l
X I
< 

# Average

Canister

Performance Dodge

tf)(ONCOO»O^M at . at * a* . :*.:*• . « - -* L « — r o

•c o Ic n

# Abilit y to Absor b HC , gm s I -----M M M r4*Cr>OBOhJ*0kO»O(S > 

## oooooooooooo o

I •I I I •I . I I I •I I I I I I I

C D CZ

8 2 -

9 6 dP.9 7

- 2 9 -



### APPENDI

X

# TABL E A- l
PURGE FLO W RATE S DODG L

STEAD YSTAT E A T 2 5 MP H 3 5 MP H 5 0 MP H 

# .ACTUA L 0.90 , 0.92 , 0.7 7 3.82 , 3.7 7 5.38 , 5.3 0 LOS S O F A/ F COHTROL
6. 2 L/ M 

# 10. 8 L/ M 

# 16. 1 L/ H c o 

## o



# AVERAG E OVE RLA- 4 1.2 , 1.4 , 1. 4 L/ M

C O o o3 1 - P.9 9



# H 

# 55 5

i n o o o o

^ 

# I

UJ t o



# "

2 

# 55 5

O O O O O O

y>fAf ^

LA LA L

A o o

o o



### o o

O O L A O C N F A L A



### o

C/ 5- 3 2 P.10 0

TABL E A- 3



### N Av g ' 9 S x q DUD

7 

### 8.9 0 9.0 9 8.8 8 8.9 9 9.1 0 8.9 7 8.8 5 8.9 0 8.7 7 9.1 0 8.3 5 8.9 6 9.2 6 9.2 0 8.9 2

8.5 8 8.6 1 8.7 3 8.7 7 8.8 3 8.7 4 8.8 0 8.4 2 8.4 2 9.0 4 9.0 4 9.1 6
2 7 8.8 7 0.2 4 RV P1 

### D F TES T FUEL S 10. 5 RV P


### 10.4 2 10.3 3 10.6 4 10.7 3 10.4 0 10.3 7 10.6 2 10.3 6 10.5 2 Batc h 1

10.4 5 10.7 4 10.1 2 10.3 3 10.6 7 10.1 4 10.2 3 10.4 1 10.6 3

1 8 .10.4 5 0.1 9 Batc h 2 11.3 7

11.4 6 11.5 8 11.6 2 11.6 9 11.5 6 11.6 5 11.6 7 11.7 6 12.0 5 11.3 3 11.6 8 11.1 8 -



### 1 2 RV P
11.4 4 11.4 4 11.9 0 11.7 2 11.6 9 11.6 9 11.8 6 11.5 6 11.7 4 11.8 5 11.8 2 11.4 4

25 11.6 3 0.2 0

N Av g 

## s y 

### 9.6 7 9.4 8 9.5 0 9.4 8 9.6 7 9.5 0 9.9 8 9.5 7

9.6 6 9.3 4 9.5 5 9.2 5 9.6 4 9.3 7
1 4 9.5 5 0.1 8 10.6 8

10.8 9 11.0 4 10.6 8 10.8 9 11.0 4 11.3 3

11.3 3 11.0 5 10.6 7 10.7 2

1 1 10.9 4
n 2 4 

### 11.7 4

12.1 1 12.1 9 11.6 4 11.6 2 11.5 6 11.6 2 11.7 7 11.6 2

11.5 6 11.3 9 11.6 0 11.7 2 12.1 1 12.1 9 12.0 2 2 4 11.8 3 0.3 0 11.6 4

11.7 4 12.3 7 11.5 4 12.2 6 12.4 9 11.9 7 11.6 8P. 1

" ' • •>- i

-



# HOHINA L RV P BATCH NO . IPB T 5 Z EVA P ° P T 10ZEVAPO P T 20 Z EVA P ° F T 30 Z EVA P ° F T 40 Z EVA P ° P T 50 Z EVA P ° P T 60 Z EVA P ° P T 70 Z EVA P ° P T 80 Z EVA P ° P T 90 Z EVA P ° P T 95 Z EVA P ° F FBP GRAVIPf , LBS/GA

L - 3 3 •



# TA W f A- 4 TPSTPtlf i mspfCTiON S 

# 9 1 8 6 11 3 13 4 17 2 20 0 21 6 22 8 23 8 25 8 27 6 32 0 34 9 39 4 6.18 1 9 2 9 0 11 1 13 0 16 7 19 6 21 5 22 8 23 7 25 3 27 6 32 0 34 9 39 2 6.14 8 

# 1SL1 1 8 3 10 4 12 2 15 9 19 2 21 2 22 6 23 7 25 0 27 4 31 5 34 5 39 5 6.15 4 2 8 1 10 8 12 9 16 6 19 6 21 5 22 8 23 8 25 3 27 6 32 0 34 9 38 8 6.12 2 

# 12 1 8 0 10 0 11 4 15 6 19 0 21 1 22 3 23 4 24 8 27 0 31 1 34 7 39 2 6.12 9 

# 1 2 2 7 7 9 7 11 3 15 6 19 1 21 2 22 8 23 6 25 0 27 4 31 5 34 4 39 3 6.10 0

### 34 P. 2

CN , - '

•' t o * - 

## ^ \ £<* r

## *T

< c n < r CS I O V O O O V O V » a a a 

### v o c n cn c n C M 

### •- • a a 

### c n 

### o 

## h q7.647.83 0 " c o 0 °8.207.890.28

0 *

li N 

### o

•»- * 

### o o oo U J 

# £
U J 

# £ U J 

### v o N 

# E 1 9 LL . 

# ft*

• • 1 — 

### U

N

O O " H 

## h M

< C O 

### vo <*

> b o



## o l vo v o V Q L O 

### P s L O

. a O O O O

W l O O ^ « - ww0 Q C M L A O O 

### K > rv . 

### « r
•a a V O V O V O 

# v- < 

# £ V O r o a a O O o

C M C M L O C M « • V O o

C O

< O O 0 "

o«= > V O C M a a V O V O



## V > 7 

## ^- $

## & e n vo v o oo ( O L O N L A a a a a L O L O L O L O ( 

### v o •- « a a V O o

L O O

C D
&

V J 

# £ 

# S

S

## TABL E A- 6 REFUELIN G EMISSIONS DQDG L

9 RV PIn . D I GEB

. 10. 5 RV

PI & D I GEfl

. 1 2 RV

PI & D I GEfl

. GZGA L Z GZGA L Z fiZGAL Z 

# 0.0 4 99. 3 8

8 0 

# 7. 5 0.0 6 

# 99. 1 8 9 - 1 

# 6. 6 0.24 97. 0 8 9 1 

# 6. 3 0.0 4 99. 3 8

8 0 

# 7. 4 0.04 99. 4 8 9 0 

# 9. 7 0.0 8 99. 0 8 8 0 

# 6. 1 0.0 3 99. 5 8

8 0 

# 9. 7 0.1 8 97. 7 8 8 0 

# 6. 5 0.1 4 98. 2 8

9 - 1 

# 4. 4

AV G

# 0.0 4 99. 3 0.04 

# 99. 3 0.0 9 98. 8 S X 

# 0.00 

# 0. 0 Q.0 2 

# 0. 2 0.07 

# 1. 1

. C O c n



# 0.0 3 99. 6 8

7 1 

# 9. 5 0.0 3 99. 6 8

8 0 

# 10. 3 

# 0.0 1 99. 8 8

8 4 

# 10. 0 

# 0.0 3 99. 6 8

9 - 1 

# 9. 7

V c oP. 4



### - 36 CMOCM*-«CML04rL0«rV 0 

### vovo«r«roioioioioiO i ^ON«M-I^K>CM— •- * 

# 4

| C N 

# H o

o o o o o c no o o o rs . o o o o rs , o o o o o o o o o o o o o o o o o o o o ioK\rs,-*r<oa»~ * o i rs . rs , « r aaaaaaaaa a a C 3 

### oovooocnrs.c2iC7ioors.o o o o * O l O l O l O l O l O l O l O l O l O l O l ""• )

LrX 

### S^ r 

### °S^SJ^Sp-a C 

### si C<< 1 

### * ° 8



# H i U J 

# g H ool

o o o o
u . 

# n s LL . 

### u . .

V J 

# i o o V J U J 

# M
LO 

### rs . 

# £ A

| L O10 

# H6.7

C M 1 0 0 0 098.85.2

C M



### rs . 0 098.90.100.097.17.65.3 0 0 — • • • 

### o o o O l



# 4

C D 

# H o r

s o i o i o o o o

— • C M L O m m m 

### o i c no o c no i o i

v o v o 

## o o
• • 

## o o O l « X • • 

### o o o O l 

# s s

v s &

### TABL E A- 8

•



# JttHIO L 4 4 4 4

10 3 10 3 

# VOLUME

5 3 1/ 2

7 1/ 2 5 EFFECT O

F CANISTE RSIZ E O N REFUELIN GEMISSIONS 1 2 RV P LITER S OF CHARCOA

L PE RGALLO N TAN KYQUffl E 0.3 6 0.2 5

0.3 0 0.2 0 • 

# G/ G

0.0 9 0.1 2 0.2 1 0.1 1 0.1 5 

# 0.1 9 0.1 6 0.0 4 0.1 6 0.5 3 0.1 9 

# 0.1 7 0.3 0 0.2 0 %



# 98. 8 98. 5 97. 3 98. 6 98. 0 

# 97 . G 98. 0 0. 6 98. 4 94. 5 98. 0 

# 98. 2 96. 9 2. 1 l a D I •



# GP M AVERAG E OF 8 RUNS 8 8 0 8 8 0 8 9 - 1 8 8 - 1 8 9 - 2 AVERAG E S X 10. 1

9. 5 10. 3 10. 1 

# 10. 1 i

i



# AVERAG E O F 1 0 RUN S 8 8 2 8 9 0 8 8 1 AVERAG E S X 9. 4

9. 8 10. 30377-V-GS M

TABL E A- 9

AVERAG E S X C O

G/ M

1.91 0 1.86 3 2.83 1 2.53 1
2.28 5 0.1 8

• Stal l H C

G/ M

0.13 5 0.10 3 0.119 » 0.11 0
0.12 6 0.0 2

a t star t 9 RV

P NO x G/ M

0.59 3 0.60 7 - 0.61 6 0.61 1
0.61 1 0.0 2 DIURNAL

G/ T 0.1 3 0.5 0 0.1 1 0.2 2
0.3 2 0.1 8

- no t include d EVA P G/ T HO T SOA K G/ T 0.1 7 0.1 3 0.1 7 0.1 7
0.1 6 0.0 2
i n aver c TOTA L

G/ T 0.3 0 0.6 3 0.6 1 0.3 9
0.1 8 0.1 6 ige . C O

G/ M

1.91 1 2.75 5 2.039 ,

2.23 5 0.1 5 BASELIN E REGULATE D EMISSION S

H C G/ M

0.11 7 0.11 1 0.01 7

0.10 2 0.0 5 DODG E .

(2 K MILES )

10. 5 NO x G/ M

0.61 6 0.61 2 0.51 5

0.60 1 0.0 5 RV

P

DIURNA L G/ T 0.3 3 0.6 2 0.8 0

0.5 8 0.2 1 •

EVA P G/ T HO T SOA K G/ T 0.1 7 0.1 8 0.1 5

0.1 7 0.0 2 TOTAL G/ T 0.5 0 0.8 0 0.9 5

0.7 5 0.2 3 C O G/ M

2.01 0 3-38 0 2.35 0

2.58 0 0.7 1 H C G/ M

0.12 1 0.15 9 0.12 0

0.13 1 0.0 2 1 2 NO x G/ M

0.63 8 0.61 5 0.73 2

0.67 2 0.0 5 RV

P

DIURNAL G/ T 3.9 5 2.3 5 0.6 5

2.3 2 1.6 5 EVA P G/ T HO T SOA K G/ T 0.2 5 0.2 1 0.1 8

0.2 2 0.0 1 TOTA L

G/ T 1.2 0 2.5 9 ' 0.8 3 t o

0 0
2.5 1 1.6 9

c

n0377-V-GS M

TABL E A-1 0 REGULATE D EMISSION S DODG E 5 L RC S

9 RVP 10. 5 RVP 1 2 RVP

AVERAG E S X C O

G/ M

2.25 1 2,03 0 2.81 7
2.37 7 0.1 2 H C

G/ M

0.13 1 0.11 2 0.19 1
0.15 7 0.0 3 NO x G/ M

0.66 5 0.72 8 0.71 6
0.70 3 0.03 3 DIURNA L

G/ T 0.6 6 0.3 1 0.5 5
0.5 1 0.1 8 EVA P G/T HO T SOA K G/ T 0.3 9 0.3 1 0.3 5
0.3 5 0.0 1 TOTA L G/ T 1.0 5 0.6 2 0.9 0
0.8 6 0.2 2 C O G/ M

2.18 3 3.16 3

2.82 3 0.18 1 H C G/ M

0.16 1 0.17 3

0.16 7 0.00 8 NO x G/ M

0.61 7 0.75 1

0.68 6 0.09 7 DIURNA L

G/ T 0.2 6 0.3 1

0.3 0 .0 6 EVA P G/T HO T SOA K G/ T 0.2 6 0.3 1

0.3 0 0.0 6 TOTA L G/ T 0.5 2 0.6 8

0.6 0 0.1 1 C O G/ M

3.21 1 3.18 7

3.20 0 0.01 9 H C G/ M

0.13 9 0.17 8

0.15 9 0.02 8 NO x G/ M

0.71 7 0.70 5

0.71 1 0.00 8 DIURNAL

G/ T 1.0 6 0.2 3

0.6 1 0.5 9 EVA P G/ T HO T SOAK G/ T 0.1 9 0.2 5

0.2 2 0.0 1 TOTA L

G/ T 1.2 5 0.1 8

0.8 6 0.5 1 i

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TABL E A-1 2 REGULATE

D EMISSION

S PONTIA C 10 3 7.5 L RC S (ECS) " . '

9 RV P10. 5 RV P' 1 2 RV P

AVERAG E S X C

O G/ M

2.93 6 2.52 8

2.73 2 0.28 8 H C

G/ M

0.27 2 0.23 6

0.25 1 0.02 5 NOx G/ M

0.61 5 0.51 1

0.57 8 0.05 2 •

DIURNAL G/ T 0.8 2 0.5 0

0.6 6 0.2 3 EVA P G/T HO T SOA K G/ T 0.9 7 0.9 5

0.9 6 0.0 1 TOTAL G/ T 1.7 9 1.1 5

1.6 2 0.2 1 C O G/ M

3.56 7 3-57 3

3-57 0 0.00 1 H C G/ M

0.30 5 0.29 9

0.30 2 0.00 1 NOx G/ M

0.66 1 0.61 2

0.65 2 0.1 3 DIURNAL

G/ T 0.5 1 0.6 6

0.5 9 0.1 1 EVA P G/T HO T SOA K G/ T 0.7 3 1.0 3

0.8 8 0.2 1 TOTAL G/ T 1.2 1 1.6 9

1.1 7 0.3 2 C O G/ M

3-39 1 3.10 1 1.11 5
3.61 7 0.13 1 H C G/ M

0.36 9 0.32 0 0.31 7
0.33 5 0.02 9 NO x G/ M

0.62 3 0.63 2 0.67 6
0.61 1 0.02 8 DIURNAL

G/ T 0.5 5 0.9 9 0.6 5
0.7 3 0.2 3 EVA P G/ T HO T SOA K G/ T 0.8 0 1.0 8 1.0 3
0.9 7 0.1 5 TOTA L

G/ T 1.3 5 2.0 7 1.6 8
1.7 0 0.3 6

T l C O