Impact of Friction ReductionTechnologies on Fuel EconomyPresented at the March 2009 Chicago ChapterMeeting of the ‘Society ofTribologistsand LubricatedEngineers’ MeetingMarch 18th, 2009George FenskeArgonne National LaboratoryOutline of PresentationOverview of Petroleum Consumption -How Much Do We Actually UseHow Does Tribology (Friction and Wear) Fit Into the Equation–If we get rid of all friction, how big of an impact will a ‘frictionless’engine have on petroleum consumption–If We reduce friction by x%, howmuch petroleum can we save?What’s Being Done (Research) to Reduce Petroleum Consumption, or,Improve Energy Security?Examples of Tribology Research Activities at Argonne Related toTransportationWorld Energy Production & Consumption1 QUAD/yr ~ 0.5 MBBL/dayWorld EnergyProduction(All Sources) 460 Quads (2005)US EnergyProduction(All Sources)72 Quads (2007)–16% of World ProductionWorld EnergyConsumption(all sectors)463 Quads (2005)US EnergyConsumption(all sectors)101 Quads (2007)–22% of World ConsumptionWorld PetroleumProduction81 MBBL/day (2007)US PetroleumProduction6.9 MBBL/day (2007)–<9% of World ProductionWorld PetroleumConsumption(all uses)85 MBBL/day (2006)US PetroleumConsumption21 MBBL/day (2006)–25% of World Consumptionhttp://www.eia.doe.gov/emeu/aer/pdf/aer.pdfUS Energy Flow (2007) - 102 QUADsQUADrillion(1015)BTUs per year1 QUAD equivalent to 0.47 million bbl crude oil/day–39.82 QUAD Petroleum -18 million bbl/dayhttp://www.eia.doe.gov/emeu/aer/pdf/pages/sec1_3.pdf13.7 Mbbl/dayUS Oil Consumption Increasing, Production Decreasing -Relying More & More on Imported Oil - Now ImportApproximately 60 % of Oilhttp://www.eia.doe.gov/emeu/aer/pdf/aer.pdfSources of Imported OilOil imported from a variety of countries, both OPEC and non-OPECPolitical stability of oil partners of concern to long-term supply and isdriving federal efforts to reduce our dependence on imported oilbydeveloping domestic supplies, alternative fuels, and energy conservationpolicies.http://www.eia.doe.gov/emeu/aer/pdf/aer.pdfMajority of Oil Consumed by ON-ROAD Vehicles - 10 to 11MBBL/Day for Cars, Light Trucks, and Heavy TrucksHow Much of the 10-11 MBBL/day of Petroleum Used for OnRoad Vehicles is Lost to Friction? - More Energy is Lost toFriction Than is Delivered to the WheelsEnergy Map- Passenger Vehicle EPA Cycle–Roughly 10% of energy input consumed byfriction–1 million barrels/day lost to friction intransportationEnergy In100%Indicated HP35%Brake HP23%At Wheels9.5%Exhaust35%Engine Cooling30%Other Engine Friction0.4%Piston Assembly2.8%Valve Train1.3%Bearings1.0%Seals0.5%Air Pumping6%Others1.6%Transmission2.0%Braking2.0%Coast/Idle4.0%Axle1.6%AccessoriesOil Pump - 0.5%Air Pump – 0.1%Water Pump - 0.1%Fuel Pump - 0.1%Power Steering – 0.5%Cooling Fan – 0.5%Alternator – 0.5%Viscous Loss – 1.35%Friction Forces – 0.95%Blowby – 0.5%Aero Drag4.0%Tires5.5%15% of IMEP(Indicated Mean EffectivePressure – HP normalizedto engine displacement)500700900110013001500170019000500100015002000Load/IMEP (kPa)

Speed (rpm)1 (52%)2 (3%)3 (4%)4 (15%)5 (8%)6 (6%)7 (8%)8 (5%)Weighting factorDetailed Studies of Heavy-Truck Friction Losses Based on MechanisticModels of Boundary and Hydrodynamic Friction Predicted Impact ofLowering Boundary Friction and Lubricant Viscosity on Fuel Economy•Rocker bushing *•Rocker tip to valve *•Pushrod to rocker interface *•Piston pin bearing *•Rings *•Piston Skirt *•Cam - follower interface *•Cam bearings *•Follower - pushrod interface*•Timing drive•Journal bearings•Crankshaft windage•Oil Pump•Fuel injection system•Crankshaft main bearings•Main seals ** interface considered in current studyFMEP calculated at 8 different modes andweighted to predict effecton fuel consumptionfor a HD driving cycleFCSF =(Fuel Consumption Scaling Factor)IMEP +ΔFMEPIMEPRole of Boundary and Hydrodynamic Lubrication Regimes- Tribological SystemDifferent regimes of lubricationdepending on the degree ofcontact between slidingsurfacesBoundary lubricationcharacterized by solid-solidcontact –asperities of matingsurfaces in contact with oneanotherContrast boundary lubricationwith full-film lubrication inwhich mating surfaces areseparated by a film.In between, mixed lubricationoccurs.BoundaryLubricationMixedLubricationFull FilmLubricationViscosity* Speed/Load

Friction CoefficientBoundary and Hydrodynamic Friction: Model Impact onFMEP and Wear SeverityTotal FMEP is the sum of the Asperityfriction and the hydrodynamic friction–Boundary FMEP decreases with increasing lubricant viscosity –shifting from BL to ML regime–Hydrodynamic FMEP increases with increasing viscosityPiston FMEP versus Viscosity Grade05101520251020304050SAE Viscosity Grade

FMEP (kPa)No Treatment TotalEst30% Reduction TotalEst60% Reduction Total90% Reduction TotalHydrodynamicAsperity / No TreatmentAsperity / Est30%Asperity / Est60%Asperity / 90%Normalized Piston - Liner Contact Severity0.00.51.01.52.02.53.03.54.04.501020304050SAE Viscosity Grade

Relative Wear LoadViscousFMEPAsperityFMEPFriction Losses are Greatest (Relative to Engine Power) atLow Speeds and High Loads - Forward-Predictive ModelingUnder idle conditions, over 50 % of energy consumed to overcomefriction (boundary and viscous) -pumping losses account for the balance40 Weight Oil71 kPaFMEP compared to 617 kPaIMEPRicardo -I Fox75096011701590180016839833251040102030405060

FMEP (% IMEP)Speed (rpm)IMEP (kPa)FMEP As a Fraction of IMEP40 wt, 0% ReductionWeighted Avg. - 11.6%71 kPA FMEP: 617kPA wt'd IMEP75096011701590180016839833251040102030405060

FMEP (% IMEP)Speed (rpm)IMEP (kPa)FMEP As a Fraction of IMEP20 wt, 90% ReductionWeighted Avg. - 8.1%50 kPa FMEP: 617 kPa IMEP30 % reduction in FMEP (71 to 50 kPa)21 kPa reduction in FMEP represents 3.5% ofIMEP - or an increase of 3.5% in fuel economy20 Weight Oil, 90% Reduction in Boundary Friction50 kPaFMEP compared to 617 kPaIMEPModeling the Impact of Friction on Fuel Efficiency andIdentifying Critical Components - HD DieselPrediction/Modeling of Fuel Savings–Systematic studies on the effect ofboundary friction and oil viscosity onfuel efficiency–Up to 1.3 % fuel economy improvementby low friction additives and/or coatings–3-4% fuel economyimprovement byreducing boundary friction and reducingoil viscosity–Additional 2-4% fuel economy gains intransmission and differential/axlePiston Rings and Skirt: Impact of Reduced Asperity Friction on Fuel Savings (gals)@ 1000 hrs Operation-100-500501001502002503000 10 20 30 40 50 60SAE Lubricant Grade

Gallons of Fuel Saved per 1000 Hours OperationBaseline Friction - 0% Reduction30% Asperity Friction Reduction60% Asperity Friction Reduction90% Asperity Friction ReductionSAE Viscosity Grade-6%-4%-2%0%2%4%01020304050

Predicted Change in Fuel Consumption0% Reduction30% Reduction60% Reduction90% ReductionBaselineSAE 40Summary10 -12 Million barrels of oil consumed per day in US for transportationOnly 10% of fuel is actually required to ‘move’the vehicle–Tires/rolling resistance–Aerodynamic dragApproximately 10 % consumed by engine frictionAnother 4-6 % consumed by transmission/drivetrainlosses–Gears. Seals, ChurningReducing boundary (asperity) frictionby itself can be beneficial (1%)Reducing viscosity by itself is limited to 20 WT before boundary/asperityfriction increases (1/2%)Reducing boundary/asperity friction enables the use of lower viscosityfluids and even greater fuel savings (3-5 %)–However -lower viscosity fluids will result in higher ‘wear’loads andthus require more wear resistant/durable materials/interfacesSources for Further Information on Department of Energyand Argonne Activities on Transportation:http://www.transportation.anl.gov/Sources for Further Information on Department of Energyand Argonne Activities on Transportation:http://www1.eere.energy.gov/vehiclesandfuels/Argonne Tribology Activities - Reducing Friction,Improving Durability & ReliabilityModeling–Collaborations with Ricardo to modelimpact of friction on fuel economy–Importance of boundary layer friction in it’srole to enable the use of low-viscositylubricantsAdvanced Materials & Coatings–Over 20 years of researchfocusing on the development oflow friction, wear-resistantmaterials for TRIBOLOGICAL APPLICATIONS•High temperature solid-film lubricationof ceramics, Low friction carbon-carboncomposites, Ultralow friction DLCs, Superhard Nanocomposites, Low friction boronbased coatingsAdvanced Additives–Layered film additives, nano-additivesCharacterization & Testing–Room temperature to 1000C, unidirectional & reciprocating motion, point, line,conformal contact, dry (vacuum, inert,hydrogen, methane) or, liquid lubrication–Advanced characterization (optical, electron, ion beam analysis)providingmorphological, microstructural, and chemical information in nearsurface regions18Pure MoN(Typical ofAll CurrentHardCoatings)2.2 % CuFrom columnar to nearly-featurless morphology1.2% CuMoNwith0.6% CuCoating Design, Development, and CharacterizationSubstrateNanoGrainsAfter acid etchingTEMAfter ion etchingGrain size: 50-70 nmErdemir,Eryilmaz‐Argonne1900.020.040.060.080.10.12051015KTF 210DepthLoad (mN)E/(1-v2) = 401.23 +/- 17.18 (GPa)Hardness = 67015 +/- 4683 (N/mm2)Wp = 0.14 nJ (%15)We = 0.79 nJ (%85)Sputter ion plating systemHardness BehaviorMechanical/Tribological CharacterizationTunable between 30 to 60 GPaNote that coating fractures, butdo not delaminate, “good sign forstrong adhesion”Mercedes Adhesion TestRockwell CIndentSuperhard Coating vs Steel Pin in Mobil1 10W3020 N load, 10 rpm , 30 mm track diameter00.020.040.060.080.10.120.140.160.180.20 200 400 600 800 1000 1200 1400Distance (m)

Friction CoefficientMoN-CuPolished with 4000 grit SiCpaperErdemir,Eryilmaz‐Argonne20Hydrogenated DLC (N3FC) orHydrogen Free a-C Deposition:N3FCMagnetron Sputtering PVDGas Mixtures:CH4and Ar gas mixture for N3FCCarbon target for deposition andplasma enhancementC Target Power : 1000-3000 WPlasma Booster is used (80-100 V)Pulsed DC BIAS350 KHz, -35 VThickness : 10 nm - 2 μmProcess Temperature : RT-150o CRoughness of Coated surface:Sa : 49.3 nmDeposition of Hydrogenated DLCs by PVDArCH4Eryilmaz,Erdemir‐Argonne21Argonne’s Superlow Friction or Nearly Frictionless Carbon(NFC) FilmsNFC Coated Lead ScrewUS NavyNFC Coated Hydrolic Pump componentCATNFC Coated Hydrogen Fuel InjectorsWestportNFC Coated Test Parts for Potential gearbox ApplicationsEatonEryilmaz,Erdemir‐Argonneμm BAnm BADevelopment and evaluation oflow-friction additive packagesand characterization ofadditive/surface chemicalinteractions.nano-additives - development ofnm-size additives that remain insuspension and reduce metal-tometal frictionSteel Ball Against Mg inPure PAO and in Boroncontaining Pure PAOLubricants & AdditivesErdemir,Eryilmaz,Erck,Ajayi‐ArgonneImpact of Additives onScuffing PerformanceInvestigation of commercialadditives to increase scuffingperformance of militarylubricants under severelubrication environments

1 0 26 6 1 6 49 0 64 9 4 31 1 8 7 1 1 0 3 1 0 21 1 059

9 5 2 9 33 1203 1047 120 1 101 3 1070 1000 1 06 1040080012001600 15W4 0 ‐ 7 5 0

1 5 W4 0 ‐ 1 0 0 0

1 5 W4 0 ‐ 1 5 0 0 R HT 2 4 0 ‐ 7 5 0

R HT 24 0 ‐ 1 0 0 0

R HT2 4 0 ‐ 1 5 0 0 15W4 0 : B o r ic Aci d 2 5 : 1

1 5 W 4 0 : B o r ic Aci d 1 0 : 1

1 5 W4 0 :Bo r ic A c i d 5 : 1 1 5 W4 0 :T CP 2 5 : 1

1 5 W4 0 :T C P 1 0 :1

1 5 W4 0 :T C P 5 :1 1 5 W4 0 :B N 2 5 : 1

1 5 W4 0 :B N 1 0 : 1

1 5 W 4 0 : B N 5 :1

1 5 W4 0 :G r a p h i te 2 5 :1

1 5 W4 0 :Gra p h i te 1 0 :1

1 5 W4 0 :Gra p h i t e 5 :1

Scuffing Load (N)Run 1Run 2Run 3Run 4AverageAvg. Scuff Load for15W/40 SK@1000 rpm•Blue – Load•Red – Friction•Green – Block Temperature•Brown – Ring/Oil Temperature•Micro-Scuffing•ScuffingBLOCK‐1018ROLLER‐52100Sliding directionSliding directionUniformity in direction of slidingAjayi,Lorenzo‐Martin,Erck‐ArgonneOPTICAL MICROSCOPY - Wear track shows formation ofbright white spots - tribo-film formation/removalparallelperpendicularPROFILOMETRY - provides detailed quantitative informationon tribo-film formation - non-uniform distributionAjayi,Lorenzo‐Martin,Erck‐ArgonneFIB Procedure - ion-beam ‘back-hoe’ to harvest ultra-thincross-sections for detailed TEM characterizationAjayi&Lorenzo‐Martin‐ArgonneAjayi&Lorenzo‐Martin‐ArgonneTEM of FIB specimen- texturing - sub-surface region,structure & composition of tribo-filmtribo-filmsub-surface grainrefinementSurface Characterization - TOF-SIMSApplication of surfacesensitive techniquesto surface filmchemistry–DLC–SHNCSulfurEryilmaz‐ArgonneSummaryUS depends on energy -25 % of energy consumed used fortransportationMore energy is lost to friction than is delivered to the wheel–10% of energy is lost to friction–Equivalent to 1-1.5 MBBL/dayLowering lubricant viscosity by itself in not sufficient -must reduce bothboundary/asperity friction and lubricant viscosity togetehrto realizesignificant energy savingsAcknowledgementUS Department of Energy -Energy Efficiency & Renewable Energy -Vehicle TechnologiesArgonne National Laboratory -UChicago, Argonne LLCTribology Section–Ali Erdemir, LayoAjayi, Robert Erck, Osman Eryilmaz–Cinta Lorenzo-Martin, Nick Demas, .....–Guldem Kartal, Christine Matta–AshlieMasoner, Qunfeng Zeng, .....