英文版-第二章-汽车燃油经济性课件

ChapterTwo-FuelEconomyofVehicleWhatisaimoffueleconomy?Tofinishtheunittransportationloadwithminimumfuelconsumption.

§2.1EvaluationIndex（评价指标）:1.Fuelconsumptionquantityperunitdistance

—Q（）单位行程燃油消耗量2.Fuelconsumptionquantityperunitdistanceandunitworkload-（）单位运输工作燃油消耗量Note:InUSAMPG（milespergallon）1mile≈1.8km;1gallon=3.758l(liter)

Americancars20~30MPG→8.3~10.4l/100kmJapanesecars28~40MPG→5.2~7.5l/100km(Prius:33km/l)§2.2CalculationofFuelConsumptionofVehicle1.TheEquationofFuelConsumptionChapterTwo-FuelEconomyofVe1Clue:

unit:Pe(kw);Ttq(N·m);ge(g/kw·h)GT(kg/h);γ(N/l);Q(l/100km);Note:Qisalwaysconcernedwithge;

:forgasolineγ=7.2(N/l)fordieselγ=8.2(N/l)

Clue:22.FuelConsumptionPerformanceofEngine2.1Fuelconsumptionperformance-neededoutputpowercharacteristicsofengine

（负荷特性）TodescribehowtheperformanceofenginedevelopswiththechangeofloadofthevehiclethatistheneededoutputpowerofengineDefinition:output-powerratio(负荷率）=(neededoutputpowerofengine)/(maximumpoweravailableoftheengine)

=u2/u0Note:

ForQ(）PeisthecorrespondingY-coordinatevalueof(Pf+Pw)/ηTcurveintheGraphofPowerEquilibrium;

gecouldbeavailablefromthe

rightgraphwithgivenn;Conclusion:（undergivenn)Peincreaseswiththedecreaseofge

underthegivenn(inmostinstance);

output-powerratioalwaysincreaseswiththedecreaseofge(inmostinstance);ge

meetsitsminimumvaluewhenthe

output-powerratio

comecloseto80%;

2.FuelConsumptionPerformanc32.2UniversalCharacteristicsofEngine（万有特性）3.PowerEquilibrium

When

levelroad&constantspeedNote:

Peisthepowerneededbythevehicletomaintaintheconstantspeeddriveonthelevelroad;ForcalculatingthefuelconsumptionPethatexistintheformulaofQ(Q=ge.Pe/1.02uaγ)mustresultfromthecalculationofPe

thatistheneededpowertomaintaintheconstantspeeddriveonthelevelroad2.2UniversalCharacteristics4Q-UaFuelconsumptionperformance-neededoutputpower

characteristicsofengine（负荷特性图）VehiclePowerEquilibriumGraph（功率平衡图）

4.Fuleconsumptioncalculationofvehiclewithconstantspeeddriveonlevelroad(StableMode)（稳定行驶）——(Q-Ua)4.1MethodOne:

Step:

Q-UaFuelconsumptionperforman5Q-UaUniversalCharacteristicGraphofEngine

PowerEquilibriumGraph

4.2MethodTwo：Step:

Q-UaUniversalCharacteristicG65.Fuelconsumptioncaculationofthevehicleunderthedrivecycle

（循环行驶工况的油耗计算）

Basicdrivecyclecomprisesoffourparts:acceleration→constantspeed→deceleration→parking5.1Thetotalfuelconsumptionofdeceleration:

basedonthefuelconsumptionofidleconditionTwowaysfordeceleration:correspondingly

Losingthepedalandslippingthegearsintoneutral（空档、怠速）

Losingthepedalandkeepingthegearsattheirdriveplaces（挂档、怠速）

Twosortsofidle（怠速）fuelconsumption:

Idlefuelconsumption（怠速油耗）

Forcedidlefuelconsumption（强制怠速油耗）

0.28ml/sUsuallytheidlefuelconsumptioncausedbythefirstwayisquitesimilarwiththeforcedidlefuelconsumptioncausedbythesecondway.So

5.Fuelconsumptioncaculation75.2Thetotalfuelconsumptionofconstantspeed:knownquantity:

So5.3Thetotalfuelconsumptionofacceleration:

5.2Thetotalfuelconsumption8

So§2.3InfluenceFactorsofFuelEconomyVehicleusageaspect1.1Ua

（givenig）ToanalyzethereasonofwhyQchangesaccordingtothetrendofhigh-low-highwiththechangeofUa

high-low-high

9Conclusion:

Theincreaseofgecausedbymuchloweroutput-powerratioisthemainfactorcausingtheincreaseofQwhenthevehicleisdrivenwithlowspeed;Althoughge

decreasesgreatlyfortheincreaseofoutput-powerratio,thetremendousincreaseofneededpower-peisthemainfactorcausingtheincreaseofQwhenvehicleisdrivenwithhighspeed;Becauseoftheabovetwoconclusions,Qcouldpossiblymeetitslowestvaluewhenthevehicleisdrivenwiththemediumrangeofspeedwheregeandpewouldescapefromgettingtheirhighvalue,andwecallthisrangeasEconomy-RangeofSpeed（经济车速区间）。英文版-第二章-汽车燃油经济性课件101.2GearChoice（givenUa）ToanalyzethereasonofwhyQisdifferentwiththechangeofgearunderagivenUaConclusion:

Qincreaseswithchoosinglowergear;Qdecreaseswithchoosinghighergear.Itisanevidencetoprovethattraditionalvehiclescouldnotwininbothaccelerationperformanceandeconomyperformance.1.2GearChoice（givenUa）To111.3MaintenanceHeremaintenancemainlyrefertothelubricationconditionsofallthemovingpartsofthedriveline.Weusuallyusecoastingperformance（滑行性能）ofthevehicletojudgeitslubricationconditionsandwecalledthisasCoastingTest(滑行实验检查）.Usuallythecoastingdistanceismorethan230meterswiththeinitialvehiclespeedof50km/hor30km/h,otherwisethevehicleisconsideredastheonewithbadmaintenance.1.4TheApplicationofTrailer1）2）Definition

MassUtilizationCoefficient（质量利用系数）QTmeansthefuelconsumptionofeachuntiemass;itistheevaluationindexofTransportationEfficiency.

1.3MaintenanceHeremaintenanc122.VehicleStructureAspect

2.1

EngineEngineisanimportantdeterminantoffueleconomyperformanceofthevehiclebecauseitistheplacewherege

comesfrom.2.2DrivelineTransmissionefficiency-ηTGearratio-igFormakingtheengineworksaccordingtotheidealcurvethereshouldbelotsofgearratiostomatchtheratioofthecalculationbehind:2.VehicleStructureAspect2.113Conclusions:

Theoptimalcurveofengineistheplacewheretheoutput-powerratiogetstheirminimumvalueunderthecorrespondingn;Largequantityofge