汽车发动机的最新技术简介(英文版)

PDF文件使用 汽油机的冷起动机理和对策2.发动机摩擦的机理、模型和减小办法 3.增压、改变压缩比等进气控制技术概要 4.稀混合气燃烧气道喷射汽油机 5.发动机动力系统的电控技术现状和未来 6.电磁式进排气阀(EMV) 7.汽油缸内直接喷射(GDI) 8.均匀混合压燃式发动机(HCCI) 混合动力汽车(HEV)10. 燃料电池(FC)汽车 PDF 文件使用 试用版本创建www. 汽油机的冷起动机理和汽油机的冷起动机理和 对策 对策 PDF 文件使用 试用版本创建www. EngineCold Start WarmEngine Cold Start UpUp Objectives Objectives fastidle Robustrepeatable first fire Rapidstabilization fastidle Goodcontrol fuelmetering Promoterapid catalyst light- (10sec.) Highexhaust temperature flowrate LowHC levels entering catalyst Minimumspark retard Fastwarm- up enginecomponents (100 sec.) Minimizeliquid fuel Highoil film temperatures reducefriction PDF 文件使用 Enginestart Engine start upprocess up process ECUpowered up Firstinjection: simultaneous cylinders,about twice stoichiometric fuel speedup Secondcylinder Goesthrough about firingcycles eachcylinder (16 combustion events) reachfast idle Setpiston stopping/ starting positions. PDF 文件使用 试用版本创建www. PDF文件使用 试用版本创建www. Engineshut Engine shut offprocess off process Engine shut-off leaves unburned fuel intake,some cylinders exhaustport manifold.Shut- down details affect start-up HC emissions. PDF 文件使用 试用版本创建www. HCEmissions Behavior EngineHC Emissions Behavior EngineStart Start UpUp ExhaustHC has two peaks: stpeak HCfrom previousstop (from missedcylinders residualfuel Directinjection? ndpeak currentstart- up process Potentialimprovements: Betterfuel injection schedule? injectorfuel cut-off Highercranking speed? betterfuel atomization? PDF 文件使用 Intakeair temperature enginespeed effects Intake air temperature enginespeed effects stst cycle mixture preparation cycle mixture preparation PDF 文件使用 试用版本创建www. stst Cycle Fuel Delivery Summary Cycle Fuel Delivery Summary temperaturesbelow ~20C, substantial injected fuel needed robust1st cycle combustion Lowdelivery efficiency efficiencydecreases significantly efficiencydecreases increaseamount fuelinjection (air mixing limited) Fuelevaporation currentPFI system fuelair mixing process betterhardware improvement mixtureformation can lowerMAP firstengine cycle facilitatesevaporation (lesser effect) muchless fuel robustcombustion (larger effect) PDF 文件使用 PDF文件使用 试用版本创建www. LiquidFuel HC Mechanism Liquid Fuel HC Mechanism Liquidfuel films piston,liner, head, intake valve when surfacesheat- up, filmslargely disappear. Intake valve headcoolant temperatures importantvariables determiningliquid fuel HC. (Shin, Cheng, Cowart, SAE 941872, 952481, 1999- 01- 3643). HCemissions index liquidfuel entering cylinder some vaporfuel: so 25% liquidwould double HC. (Landsberg et al. SAE 2001- 01- 3587). gasolineenters cylinder liquidvaporizes cylinderprior closedvalve injection about15% fuelentering cylinderstays increasesHC overwarmed- up levels. Fuelbehavior modeling LIFmeasurements (Miyagawa et al., Toyota, SAE 1999- 01- 3642) indicate cylinderliquid fuel order10- 40% fuel(warm coldengine). Relativeamounts lightfuel ends highends engine-out HC vary during warm- up, fuelinjection strategy. Liquidfilms some100 sec. Substantial fuel goes crankcase(few grams per start) lowtemperature starts. PDF 文件使用 试用版本创建www. EngineWarm Engine Warm upduring Start up during Start UpUp PDF 文件使用 试用版本创建www. FastCatalyst Light Fast Catalyst Light OffOff Technique Technique sparkretard (after TC) after start- up achieverapid catalyst light- off Wanthigh exhaust temperature lowHC prior light-off secondaryair injection. Howdo combustion rate exhausttemperature catalystentry depend sparkretard? PDF 文件使用 试用版本创建www. PDF文件使用 试用版本创建www. SecondaryAir Injection ExhaustSecondary Air Injection ExhaustSecondary air injection reduces pre postcatalyst HC concentrations highexhaust gas temperature PDF 文件使用 试用版本创建www. 发动机摩擦的机理、发动机摩擦的机理、 模型和减小办法 模型和减小办法 PDF 文件使用 试用版本创建www. Enginefriction naturallyaspirated engines, three components mechanical/rubbingfriction pumping“work” (intake/exhaust strokes) essentialengine accessories Brake, indicated, friction quantities: Power: mep: mechanical efficiency: tfbmep imeptfmep bmepimep tfmepimep PDF 文件使用 FrictionOpportunity “Space” Mostengine friction data come from steady-state warmed-up engine tests. Coldvehicle fuel economy significantlyworse than warm engine/powertrain values (e.g., oil 20Ccan double engine friction). Wearhigher coldengines: 84% ringwear occurs within 20 minutes start-up(Perrin et al., SAE 952474). In-usefuel economy benefits may largerthan FTPdriving cycle benefits. “fixing”cold engine lubrication problems may allow reduced friction under other conditions. determinewhat primarylubricant/friction/wear constraints Enginefriction “systemsproblem.” PDF 文件使用 PDF文件使用 试用版本创建www. TwoApproaches ReducingImpact EngineFriction Absolutereduction: Reduce one frictioncomponents. Relativereduction: Increase powerdensity engineso partload, friction becomes relatively less important. PDF 文件使用 试用版本创建www. ImportantCharacteristics MajorFriction Components Pistons,rings, connecting rods Valvetrain PumpingPDF 文件使用 TypicalFriction Distribution crankshaft15 11 piston, connecting rods 33 23 valve train 28 20 oil pump 15 11 water pump subtotal100 pumping work ~30 Total100 PDF 文件使用 PDF文件使用 试用版本创建www. 08/20/02PDF 文件使用 试用版本创建www. PDF文件使用 试用版本创建www. PDF文件使用 试用版本创建www. RINGPACK-OCFRICTION-OFT TLOCR TPOCR PISTON2nd Ring/LinerScraping Redistribution Ring/groove Pumping out Gas flow dragging Piston lands Gas flow driven Inertia driven Vaporization pistonGap Gap position Mist Zone Analysis MIT Oil Consumption Analysis Package PDF 文件使用 试用版本创建www. FrictionLosses PDF 文件使用 试用版本创建www. FrictionReduction Opportunities Increaseengines maximum torque (specific power) fixedvehicle performance, mechanical efficiency typicalpart load Increasepart-load intake manifold pressure reducepumping losses Fastburn witih EGR, lean GDI Variablevalve control, cylinder deactivation Boostedengines Improvedintake exhaustsystems Reducemechanical accessoryfriction PDF 文件使用 AccessoryFriction Reduction Opportunities Crankshaft offset 15mm)towards major thrust side (Toyota) Bearingsize optimization Reducedtop ring tension, ring axial width Reduceoil ring tension Ringprofile, materials Pistonskirt coatings, increase skirt clearance Reducebore distortion Linersurface finish, coatings Reducereciprocating mass 10. Valvetrain: roller followers, reduced mass 11. Water pump size, efficiency, drive 12. Oil pump performance, lubricant circulation system 13. Fan, generator, other accessories; appropriate size, drive, improved efficiency. (See Richardson, D.E., (Cummins) “Review PowerCylinder Friction DieselEngine,” ASME paper 99-ICE-196, 1999. PDF 文件使用 试用版本创建www. PossibleMax. Friction Reduction: 30 40%Possible Max. Friction Reduction: 30 Appropriatebase engine design valvetrainmechanism lubricationsystem intelligentcooling system auxiliaryunits Totalengine-plus-transmission system optimization PDF 文件使用 试用版本创建www. EngineCooling Engine Cooling DemandDemand Heat er cor icWat er pump Cont ollerBase engi ne cool ant emp.Wi demand.Vehi cl Speed40 20 60 80 100 120 0%4% 8% 7.7 5.7 5.3 2.2 1.3 ECE EUDC uelef ciency pot ent alCoolant/ Component temperature dlePart-load Full Load PDF文件使用 试用版本创建www. FuelEf cient Lubr FuelEf cient Lubr LowFriction Truck Rear Axle 1.5%FE improvement through low friction lubricants improvedgear finish. Significant friction reduction opportunity surfacefinish coatingapplications. PDF 文件使用 试用版本创建www. 增压、改变压缩比等进增压、改变压缩比等进 气控制技术概要 气控制技术概要 PDF 文件使用 试用版本创建www. BoostingBoosting Supercharge(mechanical driven compressor), better providinglow RPM boosting Turbocharge(exhaust turbine driven compressor), moreefficient Increasepeak torque Powerdensity increase can downsize equalperformance improvedpart load fuel economy octaneespecially lowengine speed high load. mayrequire reduceCR modifyvalve timing avoidknocking, which partiallyoffset FE benefits. Variablecompression ratio (VCR) VVTmay solveoctane issue, costincrease. SmartCooling: Provide more cooling highloads, variableelectric driven water pump. PDF 文件使用 试用版本创建www. CompressionRatio Increase Compression Ratio Increase Expectation:3% power FEincrease per CR Sideeffect: also increased octane requirement increaseslightly, relativelysmall CRincrease may affectemission driving cycle, because knocklimited, mayhave customersatisfaction worstunder hot/dry conditions (desert), lowspeed highload vehicleCR variation surprisinglylarge, about 3~3.5 RON standard deviation Knocksensor feedbackcontrol strategy can retardspark downshiftgear avoidsevere knock conditions, best scenario individualcylinder control, enabled ionizationsensing. Largersize cylinders benefit more from CR, haveworse octane concerns. PDF 文件使用 试用版本创建www. CRSelection Consideration CR Selection Consideration Lowspeed WOT knock: select spark retard, CR IVC combination cylindercharge variation: cylinderCR variation: Some engines have standarddeviation 3.5RON. Manufacturing tolerance Extremeenvironmental conditions: Hot/dry whether. Need special calibration cleversensor/strategy/control PDF 文件使用 试用版本创建www. Enablingtechnologies Enabling technologies Accelerometerknock sensor: one eachbank. Low cost, valveseating noise highspeeds Sparkplug ionization: additionalsensor required; individual cylinder sensing additionalion detection circuit. Cylinderpressure sensor: Provide more information combustioncharacteristics besides knock detection. High cost. VariableCR devices. PDF 文件使用 试用版本创建www. VariableCompression Ratio Variable Compression Ratio Concept Concept Variable Compression Ratio (VCR) connecting rod provideimproved thermal efficiency fueleconomy

汽车发动机的最新技术简介(英文版)

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汽车 发动机的 最新技术 简介

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