Where the Energy Goes: Gasoline Vehicles - Fuel Economy

Where the Energy Goes: Gasoline Vehicles. Only about 12%–30% of the energy from the fuel you put in a conventional vehicle is used to move it down the road, ... Skiptomaincontent Togglenavigation FindaCar FindaCar–Home CompareSidebySide PowerSearch SearchbyMake Hybrids,Diesels,andAlternativeFuelCars FindaSmartWayVehicle BestandWorstVehicles Fueleconomy.govTopTen Today'sMostViewedVehicles UsedCarLabel PrinttheGuide HelpPromoteFuelEconomy Findafuelefficientvehiclethatmeetsyourneeds Sellingyourcar?Wecanhelpyouadvertiseitsmpg. SaveMoney&Fuel DrivingMoreEfficiently KeepingYourCarinShape PlanningandCombiningTrips ChoosingaMoreEfficientVehicle TipsforHybrids,Plug-inHybrids,andElectricVehicles FuelEconomyinColdWeather FuelEconomyinHotWeather MoreInformation All-ElectricandPlug-inHybridVehicles FrequentlyAskedQuestions LocalPrices QuestionsAboutGasPrices FuelSavingsCalculator TripCalculator CanaHybridSaveMeMoney? 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Go WheretheEnergyGoes:GasolineVehicles Onlyabout12%–30%oftheenergyfromthefuelyouputinaconventionalvehicleisusedtomoveitdowntheroad,dependingonthedrivecycle.Therestoftheenergyislosttoengineanddrivelineinefficienciesorusedtopoweraccessories.Therefore,thepotentialtoimprovefuelefficiencywithadvancedtechnologiesisenormous. Combined City Highway Energyrequirementsinthisdiagramareestimatedforstop-and-gocitydrivingusingtheEPAFTP-75Testprocedure. Ingasoline-poweredvehicles,mostofthefuel'senergyislostintheengine,primarilyasheat.Smalleramountsofenergyarelostthroughenginefriction,pumpingairintoandoutoftheengine,andcombustioninefficiency. Advancedtechnologiessuchasvariablevalvetimingandlift(VVT&L),turbocharging,directfuelinjection,andcylinderdeactivationcanbeusedtoreducetheselosses. Dieselengineshaveinherentlylowerlossesandaregenerallyone-thirdmoreefficientthantheirgasolinecounterparts.Recentadvancesindieseltechnologiesandfuelsaremakingdieselsmoreattractive. more… Energyislostinthetransmissionandotherpartsofthedriveline.Technologiessuchasautomatedmanualtransmissions(AMTs),double-clutch,lock-uptransmissionsandcontinuouslyvariabletransmissions(CVTs)canreducetheselosses. Electricalaccessoriessuchasseatandsteeringwheelwarmers,lights,windshieldwipers,navigationsystems,andentertainmentsystemsrequireenergyandlowerfueleconomy. Lossesfromaccessoriessuchaselectricdoorlocksandsignallightsareminuscule,whilelossesfromseatandsteeringwheelwarmersandclimatecontrolfansaremoresignificant. Thewaterpump,fuelpump,oilpump,ignitionsystem,andenginecontrolsystemuseenergygeneratedbytheengine. BrakingLosses Anytimeyouuseyourbrakesinaconventionalvehicle,energyinitiallyusedtoovercomeinertiaandpropelthevehicleislostasheatthroughfrictionatthebrakes. Lessenergyisusedtomovealightervehicle.Solessenergyiswastedfrombrakingalightervehicle.Weightcanbereducedbyusinglightweightmaterialsandlighter-weighttechnologies. Hybrids,plug-inhybrids,andelectricvehiclesuseregenerativebrakingtorecoversomebrakingenergythatwouldotherwisebelost. more… WindResistance(AerodynamicDrag) Avehicleexpendsenergytomoveairoutofthewayasitgoesdowntheroad—lessenergyatlowerspeedsandmoreasspeedincreases. Thisresistanceisdirectlyrelatedtothevehicle'sshapeandfrontalarea.Smoothervehicleshapeshavealreadyreduceddragsignificantly,butfurtherreductionsof20%–30%arepossible. more… RollingResistance Rollingresistanceisaresistiveforcecausedbythedeformationofatireasitrollsonaflatsurface. Newtiredesignsandmaterialscanreducerollingresistance.Forcars,a5%–7%reductioninrollingresistanceincreasesfuelefficiencyby1%,buttheseimprovementsmustbebalancedagainsttraction,durability,andnoise. more… Avehiclespendssignificanttimeidlingincitydriving(stopandgotraffic),usingenergytoruntheengineandpowerthewaterpump,powersteering,andotheraccessories. Integratedstarter/generator(ISG)systems,likethoseusedinhybrids,eliminateidlingbyturningtheengineoffwhenthevehiclecomestoastopandrestartingitwhentheacceleratorispressed. EnergyrequirementsinthisdiagramareestimatedfortheEPAHighwayFuelEconomyTestprocedure(highwaydrivingwithanaveragespeedofabout48mphandnointermediatestops). Ingasoline-poweredvehicles,mostofthefuel'senergyislostintheengine,primarilyasheat.Smalleramountsofenergyarelostthroughenginefriction,pumpingairintoandoutoftheengine,andcombustioninefficiency. Advancedtechnologiessuchasvariablevalvetimingandlift(VVT&L),turbocharging,directfuelinjection,andcylinderdeactivationcanbeusedtoreducetheselosses. Dieselengineshaveinherentlylowerlossesandaregenerallyone-thirdmoreefficientthantheirgasolinecounterparts.Recentadvancesindieseltechnologiesandfuelsaremakingdieselsmoreattractive. more… Energyislostinthetransmissionandotherpartsofthedriveline.Technologiessuchasautomatedmanualtransmissions(AMTs),double-clutch,lock-uptransmissionsandcontinuouslyvariabletransmissions(CVTs)canreducetheselosses. Electricalaccessoriessuchasseatandsteeringwheelwarmers,lights,windshieldwipers,navigationsystems,andentertainmentsystemsrequireenergyandlowerfueleconomy. Lossesfromaccessoriessuchaselectricdoorlocksandsignallightsareminuscule,whilelossesfromseatandsteeringwheelwarmersandclimatecontrolfansaremoresignificant. Thewaterpump,fuelpump,oilpump,ignitionsystem,andenginecontrolsystemuseenergygeneratedbytheengine. BrakingLosses Anytimeyouuseyourbrakesinaconventionalvehicle,energyinitiallyusedtoovercomeinertiaandpropelthevehicleislostasheatthroughfrictionatthebrakes. Lessenergyisusedtomovealightervehicle.Solessenergyiswastedfrombrakingalightervehicle.Weightcanbereducedbyusinglightweightmaterialsandlighter-weighttechnologies. Hybrids,plug-inhybrids,andelectricvehiclesuseregenerativebrakingtorecoversomebrakingenergythatwouldotherwisebelost. more… WindResistance(AerodynamicDrag) Avehicleexpendsenergytomoveairoutofthewayasitgoesdowntheroad—lessenergyatlowerspeedsandmoreasspeedincreases. Thisresistanceisdirectlyrelatedtothevehicle'sshapeandfrontalarea.Smoothervehicleshapeshavealreadyreduceddragsignificantly,butfurtherreductionsof20%–30%arepossible. more… RollingResistance Rollingresistanceisaresistiveforcecausedbythedeformationofatireasitrollsonaflatsurface. Newtiredesignsandmaterialscanreducerollingresistance.Forcars,a5%–7%reductioninrollingresistanceincreasesfuelefficiencyby1%,buttheseimprovementsmustbebalancedagainsttraction,durability,andnoise. more… Highwaydrivingincludeslittletonoidling.TheEPAhighwaydrivingcycle(HWFET)includesnoidling. Energyrequirementsinthisdiagramareestimatedfor55%cityand45%highwaydriving.Seetheestimatesforcityandhighwaydrivingformoreinformation. Ingasoline-poweredvehicles,mostofthefuel'senergyislostintheengine,primarilyasheat.Smalleramountsofenergyarelostthroughenginefriction,pumpingairintoandoutoftheengine,andcombustioninefficiency. Advancedtechnologiessuchasvariablevalvetimingandlift(VVT&L),turbocharging,directfuelinjection,andcylinderdeactivationcanbeusedtoreducetheselosses. Dieselengineshaveinherentlylowerlossesandaregenerallyone-thirdmoreefficientthantheirgasolinecounterparts.Recentadvancesindieseltechnologiesandfuelsaremakingdieselsmoreattractive. more… Energyislostinthetransmissionandotherpartsofthedriveline.Technologiessuchasautomatedmanualtransmissions(AMTs),double-clutch,lock-uptransmissionsandcontinuouslyvariabletransmissions(CVTs)canreducetheselosses. Electricalaccessoriessuchasseatandsteeringwheelwarmers,lights,windshieldwipers,navigationsystems,andentertainmentsystemsrequireenergyandlowerfueleconomy. Lossesfromaccessoriessuchaselectricdoorlocksandsignallightsareminuscule,whilelossesfromseatandsteeringwheelwarmersandclimatecontrolfansaremoresignificant. Thewaterpump,fuelpump,oilpump,ignitionsystem,andenginecontrolsystemuseenergygeneratedbytheengine. BrakingLosses Anytimeyouuseyourbrakesinaconventionalvehicle,energyinitiallyusedtoovercomeinertiaandpropelthevehicleislostasheatthroughfrictionatthebrakes. Lessenergyisusedtomovealightervehicle.Solessenergyiswastedfrombrakingalightervehicle.Weightcanbereducedbyusinglightweightmaterialsandlighter-weighttechnologies. Hybrids,plug-inhybrids,andelectricvehiclesuseregenerativebrakingtorecoversomebrakingenergythatwouldotherwisebelost. more… WindResistance(AerodynamicDrag) Avehicleexpendsenergytomoveairoutofthewayasitgoesdowntheroad—lessenergyatlowerspeedsandmoreasspeedincreases. Thisresistanceisdirectlyrelatedtothevehicle'sshapeandfrontalarea.Smoothervehicleshapeshavealreadyreduceddragsignificantly,butfurtherreductionsof20%–30%arepossible. more… RollingResistance Rollingresistanceisaresistiveforcecausedbythedeformationofatireasitrollsonaflatsurface. Newtiredesignsandmaterialscanreducerollingresistance.Forcars,a5%–7%reductioninrollingresistanceincreasesfuelefficiencyby1%,buttheseimprovementsmustbebalancedagainsttraction,durability,andnoise. more… Avehiclespendssignificanttimeidlingincitydriving(stopandgotraffic),usingenergytoruntheengineandpowerthewaterpump,powersteering,andotheraccessories.Highwaydriving,however,includeslittletonoidling. Integratedstarter/generator(ISG)systems,likethoseusedinhybrids,eliminateidlingbyturningtheengineoffwhenthevehiclecomestoastopandrestartingitwhentheacceleratorispressed. Note:Energyuseandlossesvaryfromvehicletovehicle.Theseestimatesareprovidedtoillustratethegeneraldifferencesinenergyflowindifferentvehicletypesduringdifferentdrivecycles. ViewDataSources... Energyrequirementestimatesarebasedonanalysisofover100vehiclesbyOakRidgeNationalLaboratoryusingEPATestCarListDataFiles. Thomas,J.2014.DriveCyclePowertrainEfficienciesandTrendsDerivedfromEPAVehicleDynamometerResults.SAEInt.J.Passeng.Cars-Mech.Syst.7(4):2014,doi:10.4271/2014-01-2562. Baglione,M.,M.DutyandG.Pannone.2007.VehicleSystemEnergyAnalysisMethodologyandToolforDeterminingVehicleSubsystemEnergySupplyandDemand.SAETechnicalPaper2007-01-0398,2007SAEWorldCongress,Detroit,Michigan,April. Bandivadekar,A.,K.Bodek,L.Cheah,C.Evans,T.Groode,J.Heywood,E.Kasseris,M.KromerandM.Weiss.2008.OnTheRoadin2035:ReducingTransportation'sPetroleumConsumptionandGHGEmissions.MITLaboratoryforEnergyandtheEnvironment,ReportNo.LFEE2008-05RP,Cambridge,Massachusetts. Baglione,M.2007.DevelopmentofSystemAnalysisMethodologiesandToolsforModelingandOptimizingVehicleSystemEfficiency.Ph.D.Dissertation.UniversityofMichigan. Carlson,R.,J.WishartandK.Stutenberg,K.2016.On-RoadandDynamometerEvaluationofVehicleAuxiliaryLoads.SAEInt.J.FuelsLubr.9(1):2016,doi:10.4271/2016-01-0901. Rhodes,K.,D.Kok,P.Sohoni,E.Perry,etal.2017.EstimationoftheEffectsofAuxiliaryElectricalLoadsonHybridElectricVehicleFuelEconomy.SAETechnicalPaper2017-01-1155,doi:10.4271/2017-01-1155. Close AlsoInThisSection… WheretheEnergyGoes:GasolineVehicles WheretheEnergyGoes:Hybrids WheretheEnergyGoes:All-ElectricCars Mobile |Español |SiteMap |GeneralLinks |FAQ |Contacts |USA.gov |Privacy/Security |Feedback Contacts |Download EPA's MPGRatings |Find and Compare Cars |USA.gov |Info for Auto Dealers |Privacy/Security |Feedback ThiswebsiteisadministeredbyOakRidgeNationalLaboratoryfortheU.S.DepartmentofEnergyandtheU.S.EnvironmentalProtectionAgency. ThiswebsiteisadministeredbyOakRidgeNationalLaboratoryfortheU.S.DOEandtheU.S.EPA.