S 1.4 Traction-Limited Acceleration and AdhesionRatio汽车行驶的驱动-附着条件和附着率l.Traction-LimitedAcceleration（1）DrivingConditionofAcceleration（驱动条件）F =0When Level road:Constant speed: F, = OLevel road & Constant speed: F = F, + FwF=F+Fw+F+Fdu= SmF-(F,+Fw+F)dtChapter1 AccelerationPerformance
Chapter 1 Acceleration Performance §1.4 Traction-Limited Acceleration and Adhesion Ratio汽车行驶的驱动-附着条件和附着率 （1）Driving Condition of Acceleration（驱动条件） When Level road: Constant speed: Level road & Constant speed: Fi 0 Fj 0 F F F t f W 1. Traction-Limited Acceleration ( ) t f W i j t f W i F F F F F du m F F F F dt 1
（1）DrivingConditionofAcceleration（驱动条件）(等速）F=F,+Fw+FFor constant speed:（加速）acceleration:F,>F,+Fw+F（减速）deceleration:F,<F,+Fw+FSoDriving Condition isF≥F,+Fw+FTqigionrtqgF7rig 个or 个or n 个orTaor r→F2Chapter1AccelerationPerformance
Chapter 1 Acceleration Performance （1）Driving Condition of Acceleration（驱动条件） For constant speed: （等速） acceleration: （加速） deceleration: （减速） So Driving Condition is F F F F t f W i F F F F t f W i ≥ F F F F t f W i ＞ F F F F t f W i ＜ 0 0 , tq g T t g T tq t T i i F r i or i or or T or r F 2
（附着条件）(2)LimitedConditionofAcceleration> Presuming there is adequate power from the engine, theacceleration may be limited by the friction that is F。（附着力)between the tire and road for anti-skid purpose附着力：地面对轮胎切向作用力的极限值In this case F, is :F=F=FβXmax0T-Tf2 = Fx2 ≤F,= Fzo0（后轮驱动，限制车轮打滑的极限力）r（道路附着系数）Where: ΦCoefficient of adhesionusually p ranges from 0.7~0.8FzeWeight on driving wheels（驱动轮上道路垂直反力）3Chapter1 AccelerationPerformance
Chapter 1 Acceleration Performance Presuming there is adequate power from the engine, the acceleration may be limited by the friction that is Fφ（附着力） between the tire and road for anti-skid purpose. In this case Fφ is ： （后轮驱动，限制车轮打滑的极限力） Where: φ——Coefficient of adhesion （道路附着系数）, usually φ ranges from 0.7~0.8. FZφ —— Weight on driving wheels （驱动轮上道路垂直反力） F F F X z max X Z t f F F F r T T 2 2 附着力：地面对轮胎切向作用力的极限值 （2）Limited Condition of Acceleration （附着条件） 3
Average Coefficient of Frictionfor Common RoadRoadCondition（路面条件）CD0.7~0.8DryBlacktop（干沥青路面）0.5~0.6WetBlacktop（湿沥青路面）Drygravelroad（干燥的碎石路）0.6~0.7Dryearthroad（干土路）0.5~0.6Wetearthroad（湿土路）0.2~0.40.2~0.3Rollingsnowroad（滚压后的雪路）4Chapter1 AccelerationPerformance
Chapter 1 Acceleration Performance Road Condition(路面条件) φ Dry Blacktop（干沥青路面） 0.7~0.8 Wet Blacktop（湿沥青路面） 0.5~0.6 Dry gravel road（干燥的碎石路） 0.6~0.7 Dry earth road （干土路） 0.5~0.6 Wet earth road （湿土路） 0.2~0.4 Rolling snow road（滚压后的雪路） 0.2~0.3 Average Coefficient of Friction for Common Road 4
Tyre of Formula 1 racing carwettyre雨地胎Intermediatetyre中性胎dry tyre or Slicktyre干地胎5Chapter1AccelerationPerformance
Chapter 1 Acceleration Performance Tyre of Formula 1 racing car wet tyre雨地胎 Intermediate tyre 中性胎 dry tyre or Slick tyre干地胎 5