$ 1.3 Tractive Force & Driving Resistance--SpeedCharacteristics and Dynamic Characteristics（驱动力-行驶阻力平衡图与动力特性图）l.Tractive Force & Driving Resistance-Speed CharacteristicsFromDriving EquationF=F,+Fw+F+F1F=Ff, +Fwwhen level road & constant speed(DrivingResistancecomprisesof FrandFw)Chapter1 AccelerationPerformance
Chapter 1 Acceleration Performance §1.3 Tractive Force & Driving Resistance—Speed Characteristics and Dynamic Characteristics （驱动力-行驶阻力平衡图与动力特性图） 1. Tractive Force & Driving Resistance—Speed Characteristics From Driving Equation: when level road & constant speed （Driving Resistance comprises of Ff and FW） F F F F F t f W i j F F F t f W 1
TqioignrF:F, =GfFFtFw=CAu21.15Ft3F, +EwFt4ukm/hu.,TractiveForce &DrivingResistanceSpeedCharacteristics2Chapter1AccelerationPerformance
Chapter 1 Acceleration Performance Tractive Force & Driving Resistance—Speed Characteristics Ft1 Ft 2 Ft3 Ft 4 F F f W Ff a u ua ，km/ h F Gf f tq g T 0 t T i i F r 2 21.15 D a W C Au F Ft 2
FFtlFt3Ff +EwFt4km/ hu.3Chapter1AccelerationPerformance
Chapter 1 Acceleration Performance Ft1 Ft 2 Ft3 Ft 4 F F f W ua ，km/ h Ft 3
TractiveForce&DrivingResistanceSpeedCharacteristics ofAudi-A4800070006000Ft15000Ft2Ft3Z4000Ft4AFt53000Ft6Ff+Fw2000100010203050607080010011012013014015016017018019020021022023024025026027028029030031040u. /(km·h-l)Chapter1 AccelerationPerformance
Chapter 1 Acceleration Performance 0 1000 2000 3000 4000 5000 6000 7000 8000 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 ua/(km/h) F /N Ft1 Ft2 Ft3 Ft4 Ft5 Ft6 Ff+Fw 1 a u /(km h ) Tractive Force & Driving Resistance— Speed Characteristics of Audi-A4 4
(1)MaximumVehicleSpeed(km/h)Uamax(> uamax is the corresponding x-coordinate of the crosspoint of the driving resistance curve and thetractive force curve of the highest gear.F. = 0uamaxF=05Chapter1AccelerationPerformance
Chapter 1 Acceleration Performance （1）Maximum Vehicle Speed——uamax(km/h) uamax is the corresponding x-coordinate of the cross point of the driving resistance curve and the tractive force curve of the highest gear. max 0 0 i a j F u F 5
TractiveForce&DrivingResistanceSpeed Characteristics of Audi-A4800070006000Ft15000Ft2Ft3Z4000Ft4AFt53000Ft6Ff+Fw2000100010203050607080010011012013014015016017018022023024025026027028029030031040190200210u. /(km·h-")Uamax=205km/h6Chapter1 AccelerationPerformance
Chapter 1 Acceleration Performance 0 1000 2000 3000 4000 5000 6000 7000 8000 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 ua/(km/h) F /N Ft1 Ft2 Ft3 Ft4 Ft5 Ft6 Ff+Fw uamax=205km/h 1 a u /(km h ) Tractive Force & Driving Resistance— Speed Characteristics of Audi-A4 6
(2) Acceleration timeT=α=03.53.0driving on the level road2.5(z-s.w)/Ddu2.0SoIIF=F,+F+omM1.5dtIII1.0du1VIV(F, + Fw))Ha=0.5dtSm050100150ua/ (km-h-l)-a-dua41uaa31a21a0WaChapter1AccelerationPerformance
Chapter 1 Acceleration Performance （2）Acceleration time T 0 driving on the level road So 7 1 [ ( )] t f W t f W du F F F m dt du a F F F dt m du a T u u 2 1 1 du a dt 1
(2)Acceleration timeaNAu4a41424△uAu, →AT0uaAu, →△T,Howtocalculate T whichistheIevaluation index of acceleration ability?ZAT8Chapter1AccelerationPerformance
Chapter 1 Acceleration Performance （2）Acceleration time How to calculate T which is the evaluation index of acceleration ability? T u T u T 2 2 1 1 8
Acceleration ability analyses7000600000Ft2Ft3Z4000F+4F+5300cF+6+F2000300310u,/(kmh-)> The acceleration ability changeswiththe change of gear>Highergear leads to loweracceleration ability> Changing the position of pedal make the constant speed drivepossible because the tractive force-speed curve would move upanddown vertically with the change of injection system. (the force-speedcurves shown above is the upper limit ones of the vehicle)9Chapter1 AccelerationPerformance
Chapter 1 Acceleration Performance Acceleration ability analyses The acceleration ability changes with the change of gear. Higher gear leads to lower acceleration ability. Changing the position of pedal make the constant speed drive possible because the tractive force-speed curve would move up and down vertically with the change of injection system. (the force-speed curves shown above is the upper limit ones of the vehicle) 9
(tg αmax(3)MaximumGradeability1maxAB The maximum uphill grade resistance which thevehiclecouldovercome一F：（坡度阻力）AB=Gsinα.=i=αm.maxmaxmaxF,-(F, +F))F=tan3arcsinFmaxt1GOFt3F, +EWFt4Bukm/ huamaxa10Chapter1AccelerationPerformance
Chapter 1 Acceleration Performance （3）Maximum Gradeability—— —The maximum uphill grade resistance which the vehicle could overcome — Fi（坡度阻力） max max max AB Gsin i AB 10 Ft1 Ft 2 Ft3 Ft 4 F F f W u km h uamax a ， / max ( ) tan sin[ ] F F F t f w i arc G t F A B ( ) max max i tg