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ID:51555412
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时间:2020-03-23
《汽车机动车理论课件_汽车机动车理论外文翻译.ppt》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、《ElementaryVehicleDynamics》(《汽车理论》)PrefaceWhatcanwelearnfromthiscourse?What’stheaimofthiscourseTofindoutthereasonablemethodtodesignandusevehicleaccordingtotherelationshipamongtheparametersofstructureandperformanceofvehicle.(通过车辆结构参数与性能之间的关系,找到正确设计汽车的方法和合理使用汽车的途径)Chapterone–AccelerationPerformance§1.
2、1EvaluationIndex(评价指标)1.MaximumVehicleSpeed(Velocity)最高车速——uamax(km/h):(1)Definition:Themaximumspeedwhichthevehiclecangetundergoodandflatroadwithratedload(额定载荷).(2)ActualMeasurementofuamax2.AccelerationAbility(加速能力)(1)Theaccelerationabilityforstarting(原地起步加速能力)TestCondition:Fullenginepower(油门全开);Opt
3、imalshiftpointbetweengears(最佳换档时机)whicharefromlowgear(第Ⅰ档)forstart-uptohighgear(最高档)forfueleconomy.EvaluationIndex—TTisthetimeneededbythevehicletoacceleratefrom0to0.8Uamaxundertheabovetestconditionorthetimeneededtopassthroughafixeddistance(400mor¼mile(402.5m)).(用Ⅰ档起步,按最佳换档时间,逐次换至高档,油门全开,以最大加速度行驶,全力加
4、速至0.8uamax所需时间,或通过某一预定距离所需时间)(2)Theaccelerationabilityforhighspeeddriving(超车加速能力)Testcondition:Fullenginepower;Highgear(最高档)orinferiorhighgear(次高档)Evaluationindex——TTisthetimeneedtoacceleratefromtheminimumstablespeedofhighgear(最高档的最小稳定车速)to0.8Uamaxorthetimeneededtopassthroughafixeddistance(400mor¼mi
5、le).(在直接档工作时,油门全开,由该档的最小稳定车速全力加速至0.8Uamax所需时间,或通过某一预定距离所需的时间)3.MaximumGradeabilityofVehicle——imax(最大爬坡度)(1)Definition:Themaximumgradewhichthevehiclecanclimbinthefirstgear(Ⅰ档)undergoodroadconditionwithfullyratedload(额定满载).i=tgαEQ140imax=28%EQ240imax=58%α=30°(2)ActualMeasurementofimax§1.2DrivingMechan
6、icsofVehicleToanalyzethebalancebetweenTotalRoads(行驶阻力)andTractiveForce(驱动力)alongonedegreeoffreedom(自由度)thatislongitudinaldirection(纵向).1.TractiveForce(驱动力)—TorqueofEngineFlyingWheel—NumericalRatiooftheTransmission—NumericalRatiooftheFinaldrive—Totalefficiencyofdriveline—TorqueofDrivingWheel(1)Torque
7、ofEngineEnginemaybecharacterizedbyitstorqueandpowercurveasafunctionofspeed.Figure1.showstypicalcurvesforgasolineengine.Figure1.Performancecharacteristics(外特性曲线)ofgasolineFullperformanceandFullperforma
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