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The American Society ofMechanical Engineers

ROTARY DISTRIBUTOR

DIESELFUELINJECTIONPUMPStanadyne, Inc.Diesel Systems DivisionWindsor, ConnecticutApril, 1988National Historic Engineering Landmark

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HISTORY

Theyearwas1947.TheplacewasHartford,Connecticut.Dieselpowerwasabouttomakeanhistoricmove forward.

Atthattime,theworldofhigh-speeddieselpowerintheU.S.wasverylimited.Lessthan5percentofallenginesbeingbuilt,evenfornon-automotive applications, were diesels.

Dieselpowerhadproven tohave realadvantages. But formany applications, the price

wasprohibitive.Asmallormedium-size high-speeddieselenginesimplycosttoomuchcomparedtoitsgasolinecounterpart.

Thehighcostproblemcenteredaroundthedieselfuelinjectionsystemsavailableatthetime.Asimpler,lessexpensiveformoffuelinjectionwasneededbeforedieselscouldcompeteeffectivelyinthesmallormedium-size high-speedenginefield.

Theanswercamefromamanwhohadlearnedaboutdieselenginesthehardwayby installingand

Rotary Distribution Principlemaintaining diesel-electricgeneratorsetsinNewYork

City.HisnamewasVernonRoosa.Andhebroughthis answer to StanadynesHartfordDivision.

Roosa threw aside the traditional in-lineinjectionpumpwithitspumpingelementforeachenginecylinder.Instead,heusedasinglepumpingunittofeedallthecylinders.Thus,thenewpumphadthesamenumberofpartsregardlessofthenumberof cylinders.

Roosathencombined

thissimplepumpingsystemwiththeconceptoinletmetering.Thismadethepumpalmostselfgoverningandmeantthattheactualgovernorcouldbeasimple,lowcostmechanism,furthereducingthecostandcomplexityofthepump.

Theresultwasarevolutionarynewdesignthefirstsinglecylinder,opposedplunger,inletmeteringrotarydistributor-typedieselfuelinjectionpump.

Itwasthesmallest,simplestfuelinjectionpumptheworldhadeverseen,atamuchloweprice than anything available before.

Itopenedupanewworldforbuildersandusersofdieselenginesaworldthathasbeenexpanding ever since.

SimplicityMadeItPracticalSuccessdidnocomeovernightfortheRoosaMasterpump.Thindustrywasfullofskepticswhosaiditcouldnever be produced commercially. Five years oftestinganddevelopmentworkwererequiredbeforeasinglesalewasmade.Then,inMarch1952 came the first production order.HerculesMotorsCorporationwantedpumpsforOliverCletrac tractors.

ContinentalMotorsfollowedHerculesasacustomer in1953.BudaEngineCompany,whiclaterbecamepartofAllisChalmers,camenext,andby1956Waukeshaengineswereutilizing trotarydistributorpump.

Throughoutthisperiod,RoosaMasterengineerswerebusyworkingonmakingthepumpevensimpler,moreversatileandlessexpensive.

Workbeganon theRoosaMaster fuel injectpumpinMay,1947.From1947to1952,activitiewereconcentratedonlaboratorydevelopmentsand experimental installations.During1952,

productionoftheModelApumpwasbegun.Thismodelremainedin

productionthrough1955.

The rotary distribution pump played a key role in the rapid growth of diesel usage in farm tractors.

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Theperiodbetween1955and1958wasaevelopment stageduringwhichModelBandModelDpumpswere introduced.ModelB,withsandcasthousingwas the forerunnerofModelDof thediecastconstruction,andModelDwasreplacedbytheModelDBwhichbeganroduction in1958.

Ingeneral,theobjectoftheModelDBwastandardization. It incorporatedall thebasiceaturesofitsforerunners,theModelA,ModelB,andModelD,ntoone standardousingwithuilt-inpluses.Accessories suchsautomatic

Size comparison of distribution type pump (left) totraditional in-linepump.

advanceandelectricshut-offcouldbebuiltrightntotheDBhousing.Asingledeliveryvalvewasocated in thecenterof the rotor,providingmprovedpart load regularity.

Due to theinherentdesignoftheDBpump,cost-effective timing advance systems extended thediesels speed,andhence,power range to furtherencroachongasolineengineuse. Inaddition, thepump generally offered improved governorperformance,whichwasparticularlyattractive todiesel engine builders.

Most importantly,theModelDBpumpcouldbemountedeitherhorizontallyorvertically.Becauseof thepumps lowerdriving torque, itcouldbedrivenoffsmallergears thanother typesof fuel injectionpumps.Thismeant thatthepumpcouldbemountedverticallyinthelocationnormallyused for the ignitiondistributoronagasolineengine block.

Thisversatilitywasdestined tosaveenginemanufacturers thousandsofdollarsbyallowinghem touse thesamebasicblock forbothgasolineand diesel engines.

Itpavedthewayforfarmequipmentmanufacturers,whowere alreadymaking their

owngasolineengines, toget into theproductionofdieselengineswithaminimumof toolingcosts.Thismovewastohaveadramaticimpactonthegrowthofhigh-speeddiesels in thecountry.

Today,over90%ofthefarmandindustrialtractorsproduced in thiscountryaredieselpowered.Butbackinthemid1950s,thereversewas true.

Theswitchtodieselpoweronthefarmgainedmomentuminthelate1950swhen farmequipmentmanufacturers began offering diesel tractors pricedcompetitivelywith theirgasolinepoweredequivalents. Farm equipment manufacturers wereable todo thisbecause theyhadstartedproducingtheirownhigh-speeddieselengines.Theywereable tomanufacture theseengines for littlemorethan theirgasolinecounterparts, thanks in largemeasure to thesavingsachievedbyusing rotarydistributor fuel injection pumps.

Soon,AllisChalmers,Ford, InternationalHarvester

, JohnDeere, J.I.Case, andMinneapolisMolinebecamepumpusers.By1961,practicallyeverydieselfarmtractorbuiltinthiscountrywasequippedwithaRoosaMasterpump.

The firstgenerationofdieselenginesbuiltbythesemanufacturerswere basicallymodifiedgasolineengineblocks tominimize the toolingcostsassociatedwithenteringanew field.Newgenerationsofdieselengineswere soon to follow.

Farmerswerefinallyabletoenjoyalltheadvantagesofdieselpowerforaverysmallpremium.And takeadvantage theydid!Thehigh-speeddieselenginewasonitswaytobecominganimportant factor inAmerican life.

Diesel

enginebu

ilderswe

renot

theon

lycompanies interested in thenewdesign.Theintroductionofthepumpalsohadamajor impactonmanufacturersof traditional in-line fuel injectionequipmentthroughouttheworld.Theprospectofhavinga license formanufactureof the rotarydistributorpumpwasobviouslyverydesirable ifthesemanufacturerswere to compete in thesmaller, high-speed engine field.

OnMay1,1953,anagreementwas signedgrantingCAVLtd.,ofLondon,England the rights tomanufacture andmarketpumpsoftheRoosaMasterdesignfortheUnited Kingdom,with furtherexpansiontootherpartsoftheworldin subsequentagreements.

Early RoosaMaster pump configuration3

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TECHNICALBACKGROUNDGeneralDescription Anexternalviewofa

typicalpumpisshowninFig.1andaninternalsectioninFig.2.

Themain rotatingcomponentsare thedriveshaft (1), distributor rotor (2), transfer pumpblades (5),andgovernorcomponents (11).

The drive shaft engages the distributor rotorin thehydraulichead.Thedriveendof therotor incorporates two pumping plungers.

Theplungersareactuatedtowardeachother simultaneouslybyan internalcam ringthrough rollersandshoeswhicharecarried inslotsat thedriveendof the rotor.Thenumberofcam lobesnormallyequals thenumberofengine cylinders.

Fig. 1 Pump

Fig. 2 Sectional view

The transferpumpat the rearof the rotothepostivedisplacementvane-typeand isenclosedintheendcap.Theendcapalsohouses the fuel inlet strainer and transferpumpressure regulator. Transfer pump pressure isautomaticallycompensated forviscosity effecdue toboth temperaturechangesandvariousfuel grades.

The distributor rotor incorporates twochargingportsandasingleaxialborewithondischargeport to serveallheadoutlets to theinjection tubings.Thehydraulicheadcontaintheboreinwhichtherotorrevolves,themetevalvebore, thechargingportsand theheadoutlet fittings. The high pressure injectiontubings leading to thenozzlesare fastened tothese fittings.

Distributorpumpscontain theirownmechanicalgovernorcapableofclosespeedregulation.Bothall-speedandmin-max typesareavailable.Thecentrifugalforceoftheweigin their retainer is transmitted througha sleevto thegovernorarmand througha linkage tothemeteringvalve.Themeteringvalvecanbclosed toshutoff fuel through the linkagebyindependently operated shut-off lever.

Component1. Drive Shaft

2. Distributor Roto

3. Hydraulic Head

4. Delivery Valve

5. Transfer Pump

6. Pressure Regu

7. Discharge Fittin

8. Metering Valve

9. Pumping Plung

10. Internal Cam R

11. Governor

12. Governor Weig

13. Advance

14. Drive Shaft Bus

15. Housing

16. Rollers

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ulating piston

Regulating slotside

Regulating spring

Regulator

Thin plate

Orifice

Spring Adjusting Plug

Discharge side

Fig. 3 Transfer pump regulatorShoe

Theautomaticspeedadvanceisahydraulicmechanismwhichadvancesor retards thebeginningof fueldelivery from thepump.Thiscanrespondtospeedalone,or toacombinationofspeedand loadchanges.Amoredetaileddescriptionofeachpumpareawillbecoveredin the followingpages.

Transfer pump pressure regulation Refer toFig.3 for the followingdescription.Filtered, lowpressure fuel fromanoverhead tankora liftpump passes through the transfer pump inletscreen.Thisvane-typepumpconsistsofastationary linerand four spring loadedblades,whicharecarried in therotorslots.Excess fuelis recirculated to the transferpump inletbymeans of the pressure regulator piston, spring,andported sleeve. Fuelpressure from thetransfer pump forces the piston in the regulatorsleeveagainst the spring.Thepressurecurve iscontrolled by the pump displacement, springrateandpreload,and regulating slotconfiguration. Therefore, pressure increaseswith speed.

The transfer pump operates consistentlyoverawideviscosityrangedeterminedbydifferentgradesofdiesel fuelsandalsowhenaffectedbyvarying temperatures.A thinplateincorporatingasharp-edgedorifice is located inthe springadjustingplug.Flow throughanorificeof this type isvirtuallyunaffectedbyviscositychanges.Anadditionalbiasingpressureisexertedagainst the spring sideof thepistonand isdeterminedby the linear flowaroundthe regulatingpiston and the flow through theorifice.Withcoldorviscous fuelsa reducedflowoccurs through thepistonand sleeve

Plunger

Ro to r

Leaf spring

clearance,and theadditionalbiasingpressure isslight.Withhotor lowviscosity fuels theclearance flow increasesand thepressurewithinthe spring chamber increases.The regulatingspring and higher biasingpressure forcescombine tocontrol the slotarea.Thiscontrolmaintainsanearlyconstant transferpumppressureoverabroad rangeof fuelviscositiesand thusmaintainsstableautomaticadvanceoperationovervarious fuel typesandtemperatures.

Hydraulichead and rotor Fig.4showsanexplodedviewof the rotorand thepumpingplungers.Thecam rollerscontact the innersurfaceof thecam ring formandpush theplungers towardeachother for injection.Theshoesactas tappetsbetweenthe rollersandplungers.

Cam roller

Leaf spring screw

Fig. 4 Rotor and plunger

Refer toFig.5.As therotor revolves, its twoinletpassages registerwith thechargingannulusports in thehydraulichead.Transferpump fuelcontrolledby themeteringvalveopening, flowsinto thepumpingchamber forcing theplungersapart.Theplungersmoveoutward foradistanceproportional to the amountof fuel required forthenext injectionstroke. Ifonlyasmallamountisadmitted,asat idling, theplungersmoveouta shortdistance. Ifhalf-load is required,approximatelyhalf thepumpingchamber isfilled.Thisprocess isknownas inletmetering.

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Full-loaddeliveryiscontrolledbythemaximumplunger travel.Thisplungertravelislimitedbythe leafspringas it iscontactedbytheedgeof the shoes.

Roller betweencam lobes

Plunger Meteringvalve Circular

fuel passage

Rotor

Leafspring

Cam

Shoe Inletpassages Charging

passageIranster

pump

cam lobeRotor

Cam

Outlet fi

Delivery

Roller contacts

valve Discharge port

Pumpingchamber

Fig. 5 Plunger charging

RefertoFig.6.Theleafspringcontactstwopointsnear theouter endsof the rotor.As theadjusting screw is turned inward, thecenterofthe leafspringmoves inand itsendsextendoutwar

d.Th

is

increases themax

imum

plun

ger

travel.Turning theadjusting screwouthas thereverse effect.The adjustment set point isretainedby the screwhead-to-leaf spring

Cam ring

Leaf springPlungers

Fig. 6 Cam, plungers and leaf spring

frictionand thecoatingmaterialon thescrewthreads.

As the rotorcontinues to revolve (Fig.7),the inletportsmoveoutof registryand therotordischargeport indexeswithoneof theheadout

lets.The ro

llers then contactoppos

ing

cam lobeswhich force theshoes inwardagainstheplungers.Atthispointhighpressurepumpinbegins. Further rotation of the rotormoves the

Fig. 7 Plunger discharging

rollersalong thecam ramps forcing theplungetogether.During thedischarge stroke the fuelbetween theplungers isdisplaced into theaxiapassageof the rotor through thedeliveryvalveto thedischargeport.Thepressurized fuel thepasses through the outlet fitting, enters theinjection tubingandopens thenozzle.Delivercontinuesuntil the rollers travelover thecamnosesandbegintomoveoutwardly.Thepressuin theaxialpassage isthenreduced,allowingthenozzle toclose.

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VERNOND.ROOSAVernonD. Roosa

BornonafarminNewYorkstate,VernonRoosacamenaturallytohisinventiveturnofmind.Hisfather,whoraisedHolsteincattle,devised ahydraulicdam to raise thewater level,const

ructedawindmillandhadoneofthefirstmilking machines.

Fascinated bymechanics as a youngster,Roosahad to leave schoolatage15becauseofthe familys financialreverses.Hisfirstjobasagasattendantledtohisbecomingthestationmanagerwithin a year.Helefttoattendanaviation engineeringschool.DuringtheDepression,asamechanicwithalargebuscompany,he firstbecameinterestedindieselengines and finallylanded ajob installingandmaintaining adieselpower plant.

He subsequentlywenttoworkforaLongIslandfirmmakingdieselelectricgeneratorsetsforNewYorkapartments.

Hisinventionshaverangedfarbeyonddieselenginepumps.Heholds350patents,bothUnitedStatesand foreign,which fill threethickvolumes.Among themareastapler,abutane lighter foroutdoor fireplaces,anoveltoilet flush system,anailpolish removerbottlewithabrush,agas tank fillerandnumerouselectricalswitchingdevices.

Theinventorhasakeeninterestinhighereducation.Hedonatedachair inapplied sciencetoTrinityCollege,whereheoncetaughtasanadjunctprofessor,andin1984,pledged funds fora chair inmanufacturingengineeringattheUniversity of HartfordsCollegeofEngineering.Inaddition,tohelptraindisabledworkers,heinventedahandsfreeheadlanternfortheHartford Easter SealRehabilitation Center.TheCentermakesandsellstheproducttothegovernment, forest fire

Vernon D. RoosaInthefallof1939,tofill fighters,andonthe

commercialmarket.He also developed anddonatedtheequipmentformanufacturingthehead lamp.

theneed foravariable speedandoutputgenerator,heconcentratedonmakingafuelinjectionpumpthatwouldmeet thestringentrequirementsofthisapplicationandayearlaterhadoneinoperation.Aboutthistime,thearmedserviceswereseekinganewmethodforclosespeedregulationofgeneratorsets.Roosaproducedaseconddesign,simplerandextremelysmallinsizecomparedtoothermakes,withaself-containedplungercompletelysealedagainstdirt,water andoil leakage.

ThisisthemodelthatcaughttheeyeofStanadynesHartfordDivision, in1947.RoosacametoHartfordthatyearandembarkedonafiveyearprogramtoperfecthismiraculouspump,andlaterafuelinjectionnozzleandfilterdesignwhich becamewidely used.He also designed anautomaticdrillmachine,requiredforthenozzle assembly.

Vernonworked closely andwas respected byallmajorenginemanufacturersworldwide.In1986he received theSAEEdwardN.Coleengineering award.

After22 years at Stanadynenurturing hisbrainchildthroughnumerousimprovementsanddeveloping accessories, Roosa retired as vice-presidentofresearchanddevelopmenttodevotehistimetoindependentinventing,althoughheremainedaconsultanttothecompany.

At77,heisstillactiveinthedesignofnewproductsfromafullyequippedlaboratoryinWestHartford, Connecticut.

NATIONAL HISTORIC MECHANICAL

ENGINEERING LANDMARK

DISTRIBUTOR-TYPE DIESEL FUEL INJECTION PUMPHartford, Connecticut

1952

Vernon D. Roosa invented the rotary distributor-type fuel injection pump in 1941. It

provided a compact, low-cost fuel injection system for diesel engines up to 200 HP.

The first production order for 500 Roosa Master Model A pumps was received in

1952, and approximately 23 million distributor pumps have been manufactured by

Sranadyne and its licensees worldwide.

Vernon D. Roosa Inventor

Ernest J. Willson Development Engineer

Leonard N. Baxter assisted in development

American Society of Mechanical Engineers

1988

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ACKNOWLEDGEMENTS

TheHartfordSectionoftheAmericanSocietyofMechanicalEngineersgratefullyacknowledgestheeffortsofallwhocooperated in thededicationof theDistributor-TypeDieselFuelInjectionPumpasaNationalHistoricMechanicalEngineeringLandmark.TheAmerican SocietyofMechanical EngineersRichard Rosenberg, PresidentDr.WellenG.Davison,VicePresident,RegionIDonaldW.Kitchin, Jr.,HistoryandHeritage,Region I

ASMEHartford SectionRaySchneider,ChairmanTheASMENationalHistoryandHeritageCommitteeDr.EuanF.C.Somerscales,ChairmanRobertM. Vogel, Smithsonian InstitutionDr

.RobertB.GaitherDr.RichardS.HartenbergDr.J.PaulHartmanJosephP.VanOverveenDr.R.CarsonDalzell,ChairmanEmeritusCarronGarvin-Donohue,StaffLiaisonStanadyne, Inc.

ManydedicatedStanadyneemployeesplayedakeyroleinthedevelopmentoftherotary distributor pump and its subsequentplace indieselenginehistory.Stanadyne thanksthemallandwouldespeciallyacknowledgethefollowing people.George J.Michel, Jr.GeraldR.BouwkampJamesA.Taylor (deceased)Michael J.Perrin (deceased)AugustusD.RoseC.EugeneBradyPaulH.WabrekJames J. FordThomasD.HessVernonD.RoosaErnest J.Willson (deceased)LeonardN.BaxterFrankLink

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