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lu ric nt Performance and TurbochargeAnalysis for Alternate Fuel Tes

Mariusz ZiejewMechanical Engineering DNorth Dakota State U

Fargo

ABSTFACTFive T31 turbochargers used on ad irect-in jected di e se l engine were tested asp art of a p la nt fu el evaluation program. Theengine was tested on th e 20D hour durability

cycle proposed by th e Engine Hanufacturer sAssociation EMA . Part of th e evaluation wasan investigation of p remat ur e car bo n and lacquerdeposits, and wear within th e turbocharger dueto o il de t e ri ora t i on from th e hybrid fuels.The lubricant v isco sities for a ll testedfuels, except th e rnicroemulsion, were withinnormal limits. A sudden increase i n l u br ic a ti ngoj.l vis cos ity for the microemulsion Hasobserved. At th e same time, higher blow by andincreased lubricating o consumption was noted.Al l turbochargers displayed journal bearingwear bu t no rubs or unusual seal leakage wasformed. The turbine shafts shO\led variousdegrees of ho t shutdown and high tecperatureo pe ra ti on f or d ifferen t fuels. The turbinewheels and housings varied in color from a so ftgray to dark black. Varying amounts of varnishbuildup on th e turbine sh aft, th e thrustbearing, and th e t hr us t c o ll ar for th e d ifferen tfuels were observed.

INTRODUCTIONThe world petroleum situ atio n of th e pastseveral years has focused attention on th e needfo r development of altern ate fuels.The use of plant o il as altern ate fuels ininternal combustion engines ha s been studiedextensively in recent years 1 , 2 , 3 , 4 , 5 ).Vegetable o il fuels used in d i r e c t injection engines introduce a number ofproblems, th e origins of which can be tracedback to the high viscosity and t he p ol yunsaturated nature of th e o i l s . The severeengine contamination problems e xp e ri en c ed w i thunmodified plant o i l fuels have been only

p ap tially overcome by modified plant o il suchb le nd s w it h d iesel fuel or esters.A part of a vegetable fuel evaluationprogram conducted by North Dakota StateUniversity was an investigation of prematurecarbon depos its , lacquer deposits, and wearw it hi n t he turbocharger due to lubricantdeterioration from hybrid fuels.Behavior with regard to o il viscosity, o iconsumption, and blowby is an important factorwhen developing in tern al combustion engines.Those relations can be sig n ifican tly influenceby heavy contamination of t h e l U br i ca ti n g oilIn addition to engine related influences, o ilvi sc osi t y, o il consumption, and blowby may alsbe dependent on one another. For th is reason,o il vi sc osi t y, o i l consumption, and blowby weranalyzed jointly.One of th e engine components connected toth e lubrication c i r c u i t of th e engine and veryse nsi t i ve to the quality of th e lubricant is tturbocharger. Severe c on d it io n s l ea di ng todeposit formation and t he t u rb o ch a rg e r bearingfailu re ar e caused d ur in g t he o pe ra ti on andshutdown when th e turbocharger is exposed torelativ ely high temperatures.FUELS N LUBRICATING OIL PROPERTIES NCHARACTERISTICS

The fuels utilized in th is project were Ddi e se l c on tro l f ue l Phillips Reference Fuel),25 75 blend v/v) of a l k a l i - refined sunflowero il and diesel fu el, a 25 75 blend v/v) of hioleic safflower o i l and d ie se l f ue l, a non-ionsunflower o i l- a qu e ou s e t ha n ol microemulsion ana methyl e5ter of sunflower oil The sunfloweo il used in th e fuels was an alkali-refined anw i nt e ri z ed g r ad e . The microemulsion was formeby mixing 8 pa rt s vol) of sunflower o i l , 2pa rt s vol) of 190 proof ethanol and 5 pa rt s v ol) o f 1 -bu tano l. t remained a homogeneoussingle-phase system down to 15 0 C. The sunflowo il was tran sesterified into th e methyl estersunflower oil The high oleic safflower o il

01487191/87/09141623 02 50Copyright 1987 Society of Automotive Engineers Inc




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60 0

-

used fo r t he b lend forma tion represented an oilwhich had a fa i r degree of saturation (Iodinevalue = 92) and ye t was a liquid at normalambient conditions (Pour poin t : 20C). Incontrast, the sunflower oil was polyunsaturated(Iodine value = 133). The fatty aciddis tr ibut ions of the two oi ls are reported inTable 1.

Table 1Fatty Acid Distribution of Tested Plant OilsFatty Acid Abbrev. SunfloNer Safflm>lerPalmit ic c16:0 6.0 5.2Stearic C18:0 4.2 2.. 2Oleic C18: 1 18.7 76.3Linoleic C18:2 69.3 16.2Linolenic C18:3 0. 3Arachidic C20:0 0.4Eicosenoic C20: 1 0.1Behenic C22:0 1.0

500

Q0 40 0UJ0:: JI - 30 00:UJa:2UJI - 20 0

10 0

o

APPARATUS AND PROCEDURE

PERCENT DISTILLED

Fi6ure 1. Distil lation Curves of Test Fuels

i i I ill I II I I i II ( I I Ii II I I IIo 20 40 80 100

* - - - - - ~ 1001 SUllFLOWER OIL_ _ METHYLESTER MICROEMULSION

LEGEND:C DIESEL FUEL-0 - 25-75 SAFFLOWER OIL BUoNO.+ ..... ....._ 25 75 SUNFLOWER O il BLEND+ - - -- 1001 SAFFLOWER Oi l

The lubricating o il used throughout thetest was a commercially available 10H-30 gradeoi l .Table 2Test Fuel Properties

No addit ives were used in any of the fuels.Samples of the te s t fuels were analyzed usingASTM standard procedures. The cetane numbers ofthe tested fuels, except D-2 diesel controlfuel, were determined by a modification of theASTM D613 procedure (6).Table 2 and Figure 1 show several impol tantproperties of the fuels which influenced engineperformance and durability. Compared to th ereference diesel f ue l, v is co s it ie s of the testedfuels were noticeably higher. The API gravit iesand heating values were lower. The dist i l la t ioncharacterist ics were significantly different.

>.. 2: Ti>O = p l ~ .. Ibl r . A d , , ~ ~ p ol n, a t lb C,\ At 2 C ,h up l . . . p . t a t . ~ I t o t ph .Tit< I w ( , l \ ~ ) l .y I l 4 1 f h ~ .. _29 C, ,h . pPot (p,n , . I l w) 10, . , w lI lU q ~ I J .. - b ~ . O e.

A four-cylinder Allis-Chalmers dieselengine was selected for i t s typical design,relatively small size, and low fuel consumption.Engine and fuel injection system specificationsare presented in Table 3. An assembly sectionof the turbocharger, with parts identified, usedin this investigation is shown in Figures 2A and2B. The engine was installed on a laboratorydynamometer test stand equipped with appropriateaccessor ies for controlling speed, load andother operating c on dition s. P rio r to thetesting on each fuel , th e engine was completeddisassembled, a ll c ri ti ca l parts were ceasured,and the engine was rebuilt in s t r ic t accordance\ lith manufactuer s specifi.cations, folloHed by abreak-in period and injection pump calibrationon D-2 diesel control fuel (7). At th econclusion of each tes t , the engine and th eturbocharger were disassembled and th e cri t icalparts were inspected for wear and deposits.Several cr i t ical p arts o f the turbocharger Hereinspected, namely: compressor housing,compressor wheel, thrust bearing, thrust collar,

, I- /}g l ~ i , 5.111 , ,,,,1 N,,I I\,e ol.- -, l I ou1-

lJ . 1I.r l 11.)

J , l b l l ~ , H b j ~ , I ~ l;, j ,oil H,WI n,H,n,.ll n, l 11 , 1 ~ 9n .490 J1.91 29,1)0

n 4.n ~ . 1 I1.01 1.91 2.10

41 . I , b . ~ d11.01 11,001. 0.01 . JI I b . I 10.le

n . ~ 1 l I .n 1).20II.U O.Oul 0,111

. l - r t < , ~ , l.ll l I .e I ~ . 9 9

g,OI 0.1. 0.011 ) ,u l 0.0/ O.U\

. . I ~ 6

ll .1.1

--) 0

' ~ , . l ~ .J.lh

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Table 3Engine and Fuel Injection System Specifications

center housing, journal bear ings, shroud,turbine shaft , turbine wheel, and turbinehousing.During the tes t the ambient air intakefuel, and coolant outlet temperature werestabil ized within th e l imits suggested by SAEs tandards (8 ).

111111111421114261361

Qty. pe rTurboescriptionHousing-CompressorLocknutvfueel-CompressorBackplate AssemblyRing-SealCenter Housing AssemblyShroud-llheelHheel Assembly-TurbineRing-PistonRing-RetainingBearingBearing - ThrustCollar-ThrustRing-PistonBolt x 1 x .55 LO.LockplateBolt 8 x 1.25 x .39 LO.Housing-TurbineClampBolt H8 x 1.25 x .63 LO.Ring-Clamp

ItemNo.1234567891011121314151617181920214. 6 kW @ 2400 rpm

Specif ica t ion

98.43 mm/107.95 mm14.5: 1

Direct inject ion. high swirl , tonoidalcombustion chll llber

Al l is ~ h l l l l e r s4331, turbocharged and in tcrcooled ~ r ~ s t r o k e cycle

Description

Bore/StrokeCompression ra t ioH/Ul.imum output

Engine HodelTypoCombustion system

Hanufacturer

Maximum t rquS t ll ti c I n je c ti on timing

329.5 Nm @ 1800 rpm18 degrees TDe

Figure 2B. Turbocharger Parts Identification

Figure 2A. Assembly Section of th e Turbocharger

Hydrau li c speed advance

Inject ion nozzle

Nozzle opening pressureNozzle assembly

High pressure fuel l ines

~

14 degrees advance between 1400 and1600 rpmRobert. Bosch, 21 Il lIl nozzle and holderassembly27.3 MPa nfour or i f i c e s 0.32 = diameterSpray cone angle ; 160 degreesSac length 1.1 =Sac dil ll llet .e r ; 1. 0 rnrn1.83 = x 815.60 Il lIl

@

The engine was tested fo r endurance on acycle recommended by th e Alternative FuelsCommit tee of th e Engine Hanufacturer sAssociation EMA) (7). The tes t is intended foresearch and development purposes and designedto indicate durabil i ty problems in a reasonableamount of tes t time. Successful completion ofth e test is no assurance that th e fuel will beacceptable. However th e tes t will eliminatesome candidate fuels. This t es t cycle is shownin Table 4. The three hour cycle was repeatedfive times to accumulate a tota l of 15 hours ofengine operation. Average engine power wasabout 70 of rated power. After 15 hours on thcycle, th e engine was shut down fo r 9 hours.This procedure was repeated unt i l 200 hours ofth e tes t cycle had been accumulated.

Table 4EHA Durability Test Cycle

Step Speed Torque POHer Duration (min.)1 Rated Rated 602 85 Max 95 603 90 28 25 304 Low Idle 0 0 180

For data analysis f two time scales wereused: th e EMA cycle hours and engine meterhours. The engine meter time was always greatethan EHA cycle time due t o add it iona l timerequired fo r performance readings, injectionline pressure readings, and necessarycalibrations.A Simulator System was used to control th eengine test sequence which was recorded onmagnetic tape. Figure 3 presents a schematic oth e tes t control system. Three parameters were




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7ll11. >,,,

Figure 5 i nd ic at es t ha t for th e 25-75sunflower o il blend th e lubricating o ilconsumption from 0 to 105 hours of engineoperation was as low as 11.6 g h bu t between105 and 150 hours i t i nc re as ed t o 78.0 g/ h eventhough no o ut si de l ea ks could be observed.Excessive oil consumption in th is case couldlead to th e accelerated formation of deposits oth e turbine sh afts, turbine, and compressorjournal bearings and other in tern al parts of thturbochargers. The e xc es s iv e r es id u e in turnaffects th e rate of th e i nt er na l p ar ts wear.

Schematic diagram of testsimulator system

A 1 _jq .,. . 0 rIO ' ' ' cc _ * UOO , e . , , ; > . 1 ~ C , ,'IIT_ .... .1 0 .

controlled in th e tes ts : engine speed, enginetorque, and fuel injection pump t h r o t t l ep o si t i o n .

S I ( ; ~ LCONO,rIONU

Figure 3.

, , + . . . . , . - . , _ . . . . , - . , . - - r - - . . , . - ~ _ r - . , _ _ , - . , . - . . . . , - . ,

TEST RESULTS

Lubricating o i l consumption andblow-by d ur in g th e test with 25-7high ol e i c saffloHer o il blendtest

Lubricating o il consumption andblow-by dur ing th e test with 25-7sunflower oil blend.

l-lOURS OF ENGitiE OPERATlO,jI I I I I I I I

--t :I 30 _5 50 J lOS ; 0 135 150 155 150 ;:00

HOURS OF EMA C Y C ~ E,,+-...,..-,-,.,.--,-.,-....,.-.,-..,.-.-....,.-,..,.--,

Figure 6.

Figure 5.

Data fo r th e 25-75 high oleic safflower oblend in Figure 6 indicates th at only onereading, collected after 90 hours of th e EMAcycle or 116 hours of engine operation, was lowcompared to th e o th er r ea di ng s. This valueindicates sig n ifican t fuel di l ut i on of th elubricating oi l On average, th e lubr icatingo il consumption as well as th e blow-by were ofan acceptable order of magnitude.

15 45 M 00 1re 1m I ~ I ~ 1M 100 HOURS OF EMA CYCLE

10ow 10

I I I I I I I I I I I13 48 63 al lOll 125 142 162 177 ;'>le 228 247 26llHOURS OF ENGINE OPERATION

+-....,.-.,--,c-..,.-.-....,.-.,.--,c-..,.-.,-....,.-.,--,

Lubricating o il consumption andblow-by d uri ng t he t e s t with D-2di e se l control fuel

., w 00 w w HOURS OF EI lI I I I I I I I I I I I I w ,00 , m .HOURS OF ENGINE OPER.t.TlON

t1 100

B ef or e e ac h test th e engine crankcaselubricating o il l e ve l, d i sp e r si v it yc h a r a c t e r i s t i c , and viscosity of the o il werechecked. The lubricating o il consumption wasdetermined using a graduated di pst i c k. TheShell Oil Company b lo tt er t es t 9) was u tilizedto determine th e lubricating o il d isp ersiv ity .Viscosity of th e lubricating o il was determinedby a Cannon-Fenske viscometer in a Scien tificDevelopment Linematic bath a t 37.8C. Testswere conducted using ASTM method D445-74.The lubricating o il was changed a f t e r th erun-in and a f t e r every 100 hours o f o p er at io n .

LUBRICATING OIL AND BLOW-BY - Thelubricating o il consumption and blow-by withrespect to time fo r th e D-2 di e se l control fuelwas within normal l i m i t s as shown in Figure 4.

Figure 4.




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A simi,lar outcome, as fo r the 25-75 higholeic safflower o il blend, was obtained fo r th emethyl ester te s t . The lubricating o i lconsumption and th e blow-by remained at thenormal l imits a s i nd ic at ed by Figure 7.

Carbon residues on th e piston lands and inthe piston ring grooves i nf luence the ringpaclcage dynamics by changing th e magnitudes ofthe ga s pressure forces as well as th emagnitudes of th e internal forces acting on th erings. These in turn affect th e degree oflubrication oil recuperation and the sealingperformance of th e r ings. Under normallubricating conditions, o il consumption ispart icularly affected by th e amount of oil thacan be recuperated and recirculated. The moreoil that can be recuperated during th e expansiostroke and recirculated back, th e lower th e o iconsumption. Pistons with carbon depositsreduce oil recuperat ion since a smaller thannormal fr ac ti on o f th e oil in grooves andintermediate lands is returned to th elUbricating system. Piston carbon depositsreduce the leakage paths between th e pistonlands and thus restr ic t th e d is char ge o f th elubricating o il to th e lower levels. Thisbehavior causes shorter residence times of th etop ring on th e bot to o side of i t s groovebecause of a shorte r posi tive pressuredifferent ial oriented downward thus the to p rincannot perform i t s sealing duti.es properly.The blow-by variations indicated that th episton rings did not f unct ion properly and th ering zone no longer effectively sealed th ecombustion chamber. As a resul t of th eincreased blow-by of the combustion gases theentire piston barrel can be overheated, th elubricating o il film swept off and burned.Eventually th e working surface of pistons andcylinders can get dr y and may seize.For a ll tests except fo r th e microemulsionrun th e blow-by remained a t s a ti sf ac to ry levels(see Figures i j 5, 6, 7 and 8). The differencebetween the average values of blOW-by for thedifferent fuels were insignificant . Higherblow-by was observed af ter 120 hours of th e EMcycle for th e microemulsion run. General ly onthe gas flowing into th e crankcase can bemeasured. How much of th e to tal amount of ga sflows back into the combustion chamber duringthe charge cycle and after completion of theexpansion stroke is unknown. However, this bacflm, plays an important role sin ce th e backwardexpanding gases push lubricating oil into thecombustion chamber where i t forms deposits.Oil samples t aken every 15 hours were usedto determine changes in kinematic viscosity anddispersivity of the lubricating oil . Thelubricant viscosit ies measured at 400 C for thediesel fuel, th e 25-75 sunflower oil blend andthe 25-75 Gafflower oil blend were within normlimits (Figures 9 through 11). Some dilution oth e lubricating oil was observed during th emethyl ester test . This was indicated by anin i t i a l reduction followed by an increase in thlubricating oil viscosity (Figure 12). Figure13 shows th e kinematic viscosity as a functionof time fo r th e lubricating o il dur ing th enlicro- emulsion test . After 60 hours of th e EHcy cle o r 80 hours since th e in i t ia l o il change,a 50 i nc re ase i n kinematic viscosity was noted

50

0

00

Lubricating oil consumption andblow-by dur ing the test withmicroemulsion fuel.

Lubricating o il consumption andblaH-by dur ing th e t s t withmethyl ester test .

00 20 m os 0 200HOURS OF EM CYCLEI I I I I I I I I I I I I42 59 93 131 u, 158 185 03 222 OURS OF ENGINE OPERATION

+- - r - , - - r - , - - r - , - - r - r - - r - , . - . . . , . .. . . . . , r - . .,

2Ol.- -,,,--..,.--,--F 4--.--,--..,.---..,---r---r--r15 45 00 100 1m mHOURS OF EMA CYCLEI I I I I I I I I I I I31 48 66 a3 104 12.1 14.1 16.1 la l 1sa 21S 235 257

HOURS OF ~ G I N OPERATION

;; 20l 108 0-1==

F ig ure 8 .

Throughout th e run on th e microemulsion,Figure 8 indicates that lubricating oilconsumption and blow-by varied. The level ofth e lubricating o il showed increases severa ltimes indicating s ignif icant fuel dilut ion ofth e lubricating oil . This phenomenon was causedby poor piston rings dynamics and th e unburnedportion of the fuel which moved to the crankcasewith the blow-by gases, part icularly at th e lowidle portion of the used load cycle.

6

F ig ure 7.




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60 50 eo 0HOURS OF EMA CYCLEI I I I I I I m , OURS OF ENGINE OPERAl ION

f OIL CHAt/GE

~ HMlGE lI II I

Changes n lubricating o ilkinematic viscosity for th e testwith 25-75 sunflower a i l blend.

Changes in lubricating oilkinematic viscosity for the te s twith 25-75 high oleic safflowera i l blend test .

60 0 m 0 00HOURS OF EMA CYCLEI I I I I I I I I I I I I e on 229 HOURS OF ENGINE OPERATIOlJ

wU 20-1 - - - - -1 - - - - - - - - - - u

Figure 11.

Figure 10.

After 120 hours of th e EM cycle or 78 hourssince the second o il change, a sudden increasein lubricating o il viscosity from 108 oP, whichwas measured 10 hours ear l ier to 2280 oP wasobserved. At th e same time, higher blow-by andincreased lubricating o il consumption wereobserved.The excessive i nc re ases i n lubricating o ilviscosity fo r the microemulsion occurred mainlydue to o il polymerization and additionally dueto o il oxidation and soot particle accumulation.During operation at high temperatures theoxidation inhibitors present in th e o il canbecome depleted, resulting in accelerated ratesof OXidation, o il thickening, and alkalinitydepletion due to organic acid formation. Severeo il thickening poses th e high risk of o ilstarvation and t hus bea ri ng damage during th estart-up of a cold engine after an ove rn ight o rweekend shutdown at low ambient temperatures.Hydrodynamic load capacity depends on th epresence and the viscosity of the lubricant atth e instant o f sur fa ce s con ta ct . However, oncecontact occurs, th e resulting wear is alsorelated to the o il chemistry.Analysis of blot ter spot samples fo r a l ltes ts indicated t he i nc re as e in th e level ofcontamination n the lubricating o l lcontaminations are generated continuously duringnormal engine operation. These contaminants ar ecarbon dioxide , n i trogen oxides, sulfur oxides,soot, part ial ly burned and unburned fuel, waterand acids, and o il oxidation products . Variousamounts o f these products leak past th e pistonrings, valve guides and turbocharger seals toenter th e crankcase.Except for the o il samples taken at 60hours and 120 hours of the EM cycle of themicroemulsion test the blot ter spot samplesdid no t indicate any abnormal changes in th edispersive characterist ics of th e lubricant fora ll te s ts .

rO L CHAt-IOE

60 90 0 60 ,eo 0HOURS OF EMA CYCLEI I I I I 1 I I I I I I I0 00 m HOURS OF ENGINE OPERA l iON

60 90 0 m ,eo 00HOURS OF EMA CYCLEI I I I I I I I I I I I I I 77 93 168 186 OURS OF ENGINE OPERA110lJ

F igur e 9 . Changes in lubricating o ilkinematic viscosity for th e te s twith D-2 diesel control fuel.Figure 12. Changes i n lUbrica ting o ilkinematic viscosity for th e testwith methyl ester test .




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871623TABLE 5AAnalysis of Turbocharger DepositsDiese l Fue l. Reference - 320 Hours TestedLube Oi l

' : ~ ~ C ~ h ~ a ~ r ~ a ~ c ~ t ~ e ~ r ~ , ~ ' S ~ t ~ ' ~ ' c ~ S ~ = = = F @ ' ~ i g ~ s ~ ' ~ ~ ~ & i 9 : : : i i Q : : : D i ~ = =?OffiOreSsor Housing Clean. dry, no rub.ICompressor Hheel Clean, dry. no rub.

ITurbine \111eel Very dark g ray deposits ;;;::::;7:-=--;;::::-c7:-::c - ' n ~ 0 - - - r ~ u . b ~ . . . . . ~ITurbine Housing Very dark g ray deposits: - ' n ' o - - - r ~ u . b ~ . _

Thrust Bearing/Collar Clean. no signs of weaICenter Housing Turbine bore lightlyI scratched ,medium carbon - ; : : = = ~ - ; : ; : : : - : - : 7 : - : : c c - - - . d e e ~ p ~ 0 ~ s ~ l ' t ~ s L o Q . n Q . . _ n . Q . o Q s e L ~IJournal Bearings turbine discolored, 50 ::>;;;;::;;;:, - p ~ l ~ a ~ t ~ l ~ ' n ' l g L ' w ~ o Q . [ ~ ' n ~ _ ; _ ; _ ; _ ; _ - -IShroud Clean , very l i t t le: : ; ; ; : : < ; : : : : ; - o ; = ; ; : _ - - - - - - - ; d ; e ' p ~ O ~ s ~ l..t ,s

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B

TABLE 5DAnalysis of Turbocharger Deposits, - , - - - o . , . l M ~ e - t . Q h l . y . 1 - - 8 ~ s - t ~ e r r - = - - s 2 . Q B . l l - H o u : r s - - - , T e s t , , e d - :Lube Oil I: Character is t ics Figures 7 12 1lCompressor Housing Medium soot buildup I

:-o- ~ : - - : - - - - _ S d r ~ y _ ; _ , . . 1 n o c : - r . u b ~ . ,..,- ' :;-c-::_--:lCompressor Wheel Medium soot buildup I: = _ - : - - - = , _ - - - , - - - = - : - . , - - . . . d ~ r . z : y - ' c , . . 1 n o = r . u . b 7 = _ : : _ : _ ; : _ _ : _ : = _ = _ :IThrust Bearing/Collar Clean. no signs of wear][Center Housing Bearing bores clean ii l ight carbon deposits :I on nose [: ~ J - o - u - r - n - a . , . l - - = B e , - a - r . . , i - n - g - S - - - . . . T J . u = - r b ' i n ~ e - . : : v = - e = - r : : y ' l - i g = - h ; : ; : - t - o ' . n . :I wearj compressor Ji=_ : ~ e ' x c ' e 4 1 ' 1 e n ' t . . 1 c ' p n d i t ' i o J . n - -IShroud Light gr ay deposits :[Turbine Shaft Light shaft varnishing Ji ~ - - - - - - - - 2 ' - : . > 3 . , - h o ' t - s h u t d o . w n 7 s , . . , _ - - :lTurbine Wheel Light g ray deposits [i-: ~ - , - - - - - . . . . l n . Q o C . : r u E b ~ . - - . , - - - : - , . . , _ - - :lTurbine Housing Light gray deposits [i . . . . l n o C . : r u E b ~ . i

87 6

TABLE 58Analysis of Turbocharter DepositsMicroemulsion - 257 Hours TestedILube Oil J

J Character is t ics Figures 8 13 JJCompressor Housing Clean and dry. no rub. IJCompressor Wheel Clean and drY. no rub. lIThrust Bearing/Collar Light contaminate J: --= - s,;c :r a c t c .h es -o n -,-b e a r ''''n' Jg,--:lCenter Housing Bores clean l ight I: contaminate scratching JI very heavy carbon. some:: : o _ -- s' e;;a l-- l e ~ a k S . a ~ g g , e = - - - - ilJournal Bearings Heavy wear 80% i:-o- 2P,,1 - at:cin gILW Or :n L__.. _ i[Shroud Medium gray deposits [[Turbine Shaft Heavy varnish and I1 carbon buildup many :[ hot shu tdowns, some :i sticking of bearings to [i _------ . . . . ls .Qh ..a. .f t---------i[Turbine Wheel Medium gray deposits Ii , . . , _ - - - - - - - n o c : - r . u b ~ . - - , _ - - , _ - _ :[Turbine Housing Medium gray deposits Ii ..1 n 0C2:r .u -'-b. :

a. Diesel FuelFigure 4A b. Methyl ester c. Sunflower blendTurbine and Compressor Journal Bearings for Tested Fuels

d . Saf fl ower Blend e. MicroemulsionFigure 14B. Turbine and Compressor Journal Bearings fo r Tested Fuels




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a iesel Fuel b Methyl Ester c Sunflower BlendFigure 5A Turbine Shafts eposits for Tested Fuels

d Safflower Blend e MicroemulsionFigure 5R Turbine Shafts eposits fo r Tested Fuels

a iesel Fuel b Methyl Ester c Sunflower BlendFigure 6A Turbine Housing eposits for Tested Fuels




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d Safflower Blend e MicroemulsionFigure 6B Turbine Housing Deposits fo r Tested Fuels

a Diesel FuelFigure 7A b l ethyl Ester c Sunflower Bl endThrust Bearing and Thrust Collar Deposits fo r Tested Fuels

d SafflOl Jer Blend e MicroemulsionFieure 7B Thrust Bearing and Thrust Collar Deposits fo r Tested Fuels




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871623The center housings only for the dieselfuel and the methyl ester had l ight carbondeposits. The bearing bores of th e centerhousing were clean. For th e sunflower andsafflO\ver blends the tUl bine bor-e Here l igh t lyscratched due to deposits present. Uediumcarbon deposits were noted. For th enJicroemulsion th e turbine bore were clean withl ight scratching caused by th e deposit.

However, very heavy carbon buildup on th esurface of th e center housing was noted.Furthermore, some seal leakage evidence Viasobserved.

11

WE R ANALYSIS OF TURBOCH RGERSThe in i t ia l and final measurements of shaftwheel, journal bea ring , cen te r housing, thrustbearing, and clearance between t hrus t col la r andbearing groove are presented in Table 6.Based on the dimension data for the testedfuels, no significant problems were observed.All units d ispl ayed journal bea ri ng wear bu t no

unusual rubs were found. For the microeoulsion, higher wear on the thrust bearing wasmeasured; however, i t s t i l l is within th eacceptable l imits.

TABLE 6Analysis of Turbocharger Wear [mmLocation IDiesel. Reference Sunflower Oil Blend Safflower Oi l Blend 1ethyl Ester IHicroemulsion In i t ia l Final I In i t ia l Final I In i t ia l Final In i t ia l Final IIni t ial FinalShaft Wheel [ - Compressor End Journal 10.158 10.152 10.152 10.11 5 10.155 10.147 10.152 10.147 10.155 10.147- Turbine End Journal 10.160 10.155 10.152 10.147 10.155 10.145 1 0.1 52 1 0.1 50 10.155 10.147- Piston Ring Groove 1.68 70 1.676 1.676 1.68 1.68 1.73 1.73 I 1.68 1. 70Journal Bearing [ I- Compressor End 0.0. I 15.715 15.697 15.701 15.685 15.710 15.692 15.715 15.710 15.712 15.687- Compressor End. 1.0. 10.193 10.196 10.193 10.198 10.190 10.198 10.191 10.188 10.191 10.193- Turbine End 0.0. I 15.710 15.707 15.710 15.702 15.710 15.705 15.710 15.707 15.707 15.702- Turbine End 1.0. I 10.193 10.198 10.191 10.196 10.191 10.193 10.193 10.196 10.191 10.196Center Housing I- Compressor End Bore 15.806 15.809 15.804 15.804 15.804 15.804 15.806 15.806 15.804 15.804- Turbine End Bore 15.806 15.806 15.8011 15.806 15.804 15.8011 15.806 15.806 15.804 15.806Thrust Bearings- Part A 4.366 11.356 4.366 4.358 4.361 4.351 4.361 4.351 4.364 11.346- Part B 4.369 4.361 4.368 11.361 4.361 11.351 4.361 4.356 4.366 4.354- Part C 4.369 4.361 4.366 4.360 4.361 4.351 4.361 4.356 4.366 4.351Thrust Collar- Bearing Groove 4.42 4.42 4.42 4.42 4.420 4.420 4.42 4.42 4.42 4.42

SUI I RY ND CONCLUSIONS1. Lubricating o il consumption, viscosity andengine blcH-by were approximately normalduring the tests with the 25-75 saffloweroil blend and the 25-75 sunflower oil

blend.2. Small changes in th e lubricating o ilviscosity were observed dur ing th e run withmethyl ester .3. Lubricating o il consumption variedsignificantly throughout th e run withmicroemulsi.on. Several t imes , th e level ofth e lubricating oil increased, indicatingfuel dilution of th e oi l . A suddeni nc re ase i n lubricating oil viscosity wasexperienced twice. Higher blow-by andincreased lubricating oil consumption wereobserved at th e same time.4. The turbochargers disp layed varying amountsof varnish buildup on th e turbine shaftwhich i s th e indication of high temperatureoperation and ho t shutdown.5. The tested turbochargers showed differentshading of th e turbine housing in letturbine shroud, and turbine wheel. Thecoloration ranged from soft gray to black.

6.

7.

8.

9.

Al l units exhib ited journal bearing wear.The noted bearing wear can be attributed tt he ope ra ti ng condi ti ons and may no t bedirectly correlated to the type of fueltested.Only after the test on microemulsion someresidues in the o il in let passage galleryand bearing feed channels were observed.However, i t appear s that th e accumulationof depos it s a t that point o f time were no tserious.I t appears that 200 hours on the cycle isnot suff ic ient t o eva lu at e thoroughly thewear of the turbochargers parts on th edifferent fuels. One may, however,speculate that no significant wear problema re an ti cipa ted while using plant oil basealternate fuels, except for th e cases wherunusually high carbonaceous residues arepresent.Based on the above analysis, only themicroemulsion is very l ikely to produceexcessive carbonaceous residue in theturbocharger. A predict ion o f th e time offai lure of the turbocharger based on theobserved deposit accumulations a t thispoint is not possible.




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REFERENCES1. Bruwer , J J B.v.d. Bosharf, F.J.C. Hugo,J. Fuls, C. Hawkins, A.N.v.d. Walt, A.Engelbrecht, L.N. duPlessis, TheUtilization of Sunflower Seed Oi l as a

Renevlable Fuel fo r Diesel Engines, AgricUltural Energy, Vol. 2, AmericanSociety of Agricu ltural Engineers, Publ.No. 481, St. Joseph, m, pp . 391, 396,1981.2. Barsie, N.J., A.L. Humke Performance andEmission Characteristics of a NaturallyAspirated Diesel Engine with Vegetab le OilFuels,1f SAE Paper No. 810262, Society ofAutomotive Engineers, a r r e ~ d a l e PA 1981.3. Baranescu, R.A., Joseph J. Luseo,Sunflower Oil as a Fuel Extender in DirectInjection Turbocharged Diesel Engines,1I SAEPaper No. 820260, Society of AutomotiveEngineers, Warrendale, PA 1982.4. Ziejet.fski, M., The Effect of th e Level ofUnsaturation and of Alcohol Hodificationsof Plant Oil Fue ls on th e Long Term e r f o r ~ n c e of a Direct Injected DieselEngine,1f Ph.D. Dissertation, North DakotaState University, Fargo, North Dakota,1985.5. Wagner, L.E., S.J. Clark, and M.D. Schrock,Effects of Soybean Oi l Esters on th ePerformance, Lubricating Oil, and Hear ofDiesel Engines , SAE Transactions 841385,FuelE> and Lubricants Heeting Exposition,Baltimore, HD 1984.

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6. Urban, C.M., J.T. Gray, An Investigationof Hethodsfor Determining Cetane Uumbers oLow Ignition Quality Fuels,ll SAE Paper Ho.68 466 Society of Automotive Eneineers,Warrendale, PA 1968.7. Alternate Fuel Committee, EngineManufacturers Association, 2DD-HourScreening Test for A lt erna te Fuels,lI EnepgNotes fo r September 1, 1982, NorthernAgricultural Energy Center/ HorthernRegional Research Center, ARS/USDA PeoriaIL , p. 6, 1982.8. Society of Automotive Engineers, EnginePower Test Code - Spark Ignition andDiesel , J1349, 1980.9. Lewis, R.J. , Oilprint Analysis PreventsBreakdown, Cuts Haintenance of PipelineConstruction , Shell Oi l Company J Inc. , NeYork, NY 1960.ACKtlOIILEDGEf:EIIT

The author expresses h is ap pr ecia tio n toth e folloWing fo r their contribution to thiswork: Dr. G. Prat t and K. Kaufman fromAgricul t.ural Engineer ing, UDSGj also Aipeeear'chIndustria] Division fo r per'for'ming th e analysisof th e turbochargers.




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This paper is subject to revision. Statements and opinions ad-vanced in papers or d iscussio n are the a ut ho r s a nd are hisresponsibility not SAE s; however. the paper has been editedby l for uniform styling and f or mat. Discussion will bep ri nt ed wi th t he p ap er i f i t is published in SAE Transactions.t:or pL rmission to publish this paper in futi or in part contadthe SAE Publications Division.

Persons ishing to su bmi t papers t o e considered for pre-sentation or publication through SAE should send the manu-script o r a 30 0 word ab st ra ct of a proposed manuscr ipt to:Secretary [nb ineering Activity Board. SA.Printed in U.S.A.




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