《汽车理论》课程教学课件（英文讲稿）第1章 汽车动力性 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）

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