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# OAR Box 1830 Prepped byOllie Stewart



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Number: 

# 193 ) IV-C-160 Docket Number: 

# A-87-1 1

Printed 11/13/20087:21:01 AM Sheet 193 of 232P.2

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UNITE D STATE S ENVIRONMENTA LPROTECTIO N AGENC Y 

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. MICHIGA N 4810 5 OFFIC E O F AI R AN D RADIATIO N 

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Mr . Georg e Parke r Associat e Administrato r fo r Enforcemen t Nationa l Highwa yTraffi c Safet yAdministratio n 40 0 Sevent hStreet , S W Washington , D C 2059 0 Dea r Mr . Parker : Thi s lette r i s i nrespons e t o you r reques t fo r mor e informatio nabou t th e result s o f ou r onboar d vehicl e developmen t project . W e believ e w e hav e bee nquit e successfu l i napplyin g ou r simplifie d onboar d refuelin g concep t t o a For d Tauru s vehicle . Th e followin g paragraph s wil l briefl y summariz e ou r approac hand th e result s w e hav e obtained . Al l o f thi s materia l wil l b e covere d i nmor e dept hdurin g th e briefing s w e hav e suggeste d fo r yo u and you r staff . A s yo u know , EPAha s previousl yapplie d simplifie d onboar d refuelin g control s t o th e fue l system s o f lat e mode l Genera l Motor s and For d products . W e demonstrate d ou r syste mo na G M Cutlas s Cier a fue l tan k i n th e Sprin g o f 198 8 and o na For d Tauru s fue l tank i nthe Fal l o f 1988 . Bot ho f thes e system s performe d a s w e had desired . The yeliminate d spitback , me t ou r propose d refuelin g emissio n standar d an d ha d excellen t fillabilit yfo r condition s meetin g th e volatilit yand dispensin g rat e limit s whic hEP Ahad proposed . However , bot h G Man d For d subsequentl yclaime d tha t thi s syste mdi d no t wor k whe ninstalle d o nproductio nvehicles . AP I ha d als o buil t prototyp e vehicle s using concept s simila r t o ours , whic h experience d bot hperformanc e an d emission s problem s i nNHTS A an d EPAtesting . Inrespons e t o thes e developments , and t o dea l wit hobjection s tha t the EPAsyste mdemonstration s ha d no t deal t wit hvehicl e purg e controls , w e decide d t o evaluat e th e potentia l fo r a vehicle-base d system . Ou r bigges t concer nstemme d fro mth e fac t tha t w e wer e no t i na positio nt o b e abl e t o significantl ymodif yanyvehicle' s purg e contro l strategy . T o increas e overal l purg e amount s withou t affectin g emission s o r driveabilit ycoul d requir e modification s t o purg e strategya s wel l a s purg e flo wrates . Becaus e thes e function s ar e controlle d b yth e vehicle' s computer , w e wer e no t i n a positio nt o easil ymak e modifications . Therefore , ou r desir e wa s t o determin e i f ther eP. 3



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wer e anycurren t productio n vehicle s whic hmigh t alreadyhav e sufficien t purg e t o handl e a n onboar d system . Base d upo n screenin g o f ou r runnin g los s tes t dat a and som e subsequen t in-hous e evaluations , w e identifie d th e For d Tauru s a s apparentl yhavin g sufficien t purg e fo r a nonboar d canister . A Tauru s wa s therefor e selecte d fo r evaluation . W e face d a furthe r obstacl e i ntha t curren t in-us e condition s fo r bot hfue l dispensin g rate s an d volatilit yexcee d thos e limit s whic hw e had propose d t o accompanyonboar d controls . However , w e fel t i t importan t tha t an yvehicl e whic h w e migh t develo p b e abl e t o perfor msatisfactoril yfo r curren t a s wel l a s futur e conditions . Thi s mean t tha t improvement s woul d hav e t o b e mad e t o ou r origina l desig nt o increas e it s abilit yt o perfor munde r advers e in-us e conditions . W e fel t tha t improvement s woul d b e neede d i nthre e keyareas : reduce d flo wresistanc e fo r th e liqui d sea l an d reduce d pressur e losse s frombot hth e anti-spitbac k valv e and th e rollover/ven t valve . W e hav e mad e th e neede d improvement s b ychangin g th e liqui d sea l devic e fro m a narrowe d sectio no f th e fillpip e t o a n "overflow " tube , an d b yimprovin g th e anti-spitbac k and rollover/ven t valves . Overall , th e syste mremain s th e sam e i n basi c concep t an

d operatio na s ou r earlie r versions . Th e syste ma s w e no whav e i t installe d o nth e Tauru s vehicl e ha s bee npu t throug ha nextensiv e amoun t o f testing . "Th e rollover/ven t valv e itsel f ha s bee nrollove r teste d o n a fue l tank usin g th e rotatio nrate s o f FMVS S 301 , wit hzer o leakag e fo r eithe r lef t o r righ t rollovers . Refuelin g emission s whe nmeasure d o nth e ful l propose d EP Ates t procedur e ar e verylow , simila r t o ou r previou s hardware . Ther e ar e n o discernibl e effect s o f the refuelin g syste mo nexhaus t o r evaporativ e emissions , and driveabilit yappear s no t t o b e affected . W e hav e mad e n o modification s t o th e stoc k purg e system . Ou r mos t intensiv e testin g an d developmen t wor k ha s bee n directe d a t fillabilit yevaluations . I nou r laborator ytestin g w e hav e simulate d condition s fa r mor e challengin g tha n any found in-use , wit hflo wrate s u p t o 15. 1 gallon s pe r minut e (the limi t o f ou r dispensin g equipment ) and fue l RV P o f 14-1 5 psi . I nthi s testing , th e onboar d ca r ha s n o spitback . Back-to-bac k test s o f a stoc k Tauru s generate d som e fue l drople t spra ydurin g fillin g and som e spitbac k a t th e end o f th e fill . Othe r lat e mode l domesti c car s wer e generall yeithe r unabl e t o fil l a t thes e conditions , o r produce d frequen t prematur e shutoff s an d larg e amount s o f spitback . W e hav e als o don e a substantia l amoun t o f testin g a t loca l servic e stations . W e hav e found 14-1 5 ps i RV P fuel , hig hspringtim e temperature s and dispensin g fate s ove r 1 2 gallon s pe r minute .P. 4 

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- Th e onboar d and stoc k ca r ar e comparabl e i nthei r abilit yt o fil l unde r suc hcondition s wit hlittl e o r n o spitback . W e found othe r stoc k vehicle s t o hav e significan t problem s wit h spitbac k and prematur e shutof f fo r thes e conditions . I nsummary , w e believ e w e hav e successfull yadapte d ou r simplifie d refuelin g hardwar e concep t t o th e Taurus . I t meet s al l curren t and propose d emissio n standards , whil e a t th e sam e tim e maintainin g othe r vehicl e performanc e characteristics . W e loo k forwar d t o th e opportunit yt o provid e yo u a firs t hand briefin g o nth e result s o f ou r wor k and t o sho wyo u ou r car . Sincerel yyours , 

# X Charle s L . Gray/v/r . Director ' Emissio nContro l Technolog yDivisio n

cc : Barr yFelrice , NHTS A

7018 W