【正文】 otherwise, because the speed is higher, the speed variety district is wider. Rolling resistance power at low speed is a straight line, but at higher gear is two orders curve. The air resistance power curve is three orders function. At low speed ,the rolling resistance power is main factor, but at high speed, the air resistance power is main one. 106/109 )PP(PP wfTes ??? ?1汽車(chē)后備功率越大，汽車(chē)動(dòng)力性越好。 neglect shift gear spending time. (normal distribution t= s) Use of puting acceleration time: to determine MV acceleration ability, tradeoff powertrain。 汽車(chē)行駛方程式反映了汽車(chē)行駛時(shí)，驅(qū)動(dòng)力和外界阻力之間的普遍情況；若 已知 82/109 balance Between Traction driving MV resistance dtdumAuCmgmgfriiTFFFFFaDTgtqjiwft????????????sincos0The driving equation shows the correlation between the traction and driving resistance when the MV drives. If ACrii DTg ,0 ??are known, can analyze then the driveability of MV on the good road to face, namely at full acceleration pedal, the MV may attain the max. speed, acceleration ability and grade ability. 83/109 驅(qū)動(dòng)力與行駛阻力平衡圖 定義：為了清晰地描述汽車(chē)行駛時(shí)受力情況及其平衡關(guān)系，通常將平衡方程式用圖解方式描述，即將驅(qū)動(dòng)力Ft和常見(jiàn)行駛阻力 Fw 和 Ff 繪在同一張圖上。飛輪慣性力矩作用在汽車(chē)的橫截面上，而不作用于 車(chē)輪上 。twppii)iidtdurIrT(Fii)dtdIT(TFFFdtdum???0020123???????飛輪慣性矩 Flywheel inertial 58/109 車(chē)體受力分析 (續(xù) ) forces on the body wpp FFFdtdum ??? 12312111 )( fwp FdtdurImF ???Tggftq39。 44/106 Fw的 影響 因素： CD和 A。 其在數(shù)值上等于汽車(chē)驅(qū)動(dòng)力Ft與滾動(dòng)阻力 Ff之差 22222ftftxftxFFrTrTFTTT??????22 ≈? xtft FFFF 42/109 定義 ：汽車(chē)直線行駛時(shí)受到的 空氣阻力在汽車(chē)行駛方向上的分力 。 轉(zhuǎn)速高，胎面離心力大。 Roll resistance can39。6 517177。 3 291177。s efficiency Power loss Liquid L. Mecha. L. Rub Lubr. 20/109 傳動(dòng)系機(jī)械效率 ηT Transmission39。 Max. speed, means that the vehicle drives on the straight and even and good (concrete or asphalt) roadway can reach at the average and largest speed. 7/109 時(shí)間汽車(chē)加速過(guò)程曲線 Velocity Time Diagram of velocity vs time vehicle acceleration history 車(chē)速 Gear shifting 8/109 爬坡能力的評(píng)價(jià) 以滿載、良好路面上的 imax來(lái)表示 : －－ 商用車(chē) 30％ 或 ； －－ 越野汽車(chē) 60％ 或 31186。 ② 建立行駛方程式 。 ③ With the form of the diagram, the table or the plait distance), press the vehicle tractive evaluation index, make sure the motion of the vehicle. 汽車(chē)動(dòng)力性 Veh. Perf. 3/106 第一章 汽車(chē)動(dòng)力性 汽車(chē)動(dòng)力性評(píng)價(jià)指標(biāo) 汽車(chē)驅(qū)動(dòng)力和行駛阻力 汽車(chē)驅(qū)動(dòng)力－附著條件以及附著力 汽車(chē)驅(qū)動(dòng)力－行駛阻力平衡圖 汽車(chē)功率平衡 Traction performance evaluation index Traction forces and the resistance as vehicle driving Driving traction force , adhesive condition and its forces Balance diagram between the traction force driving resistance Power balance Vehicle traction performance 4/109 汽車(chē)動(dòng)力性評(píng)價(jià)指標(biāo) 最大車(chē)速 umax 加速時(shí)間 t 最大爬坡度 imax Index Evaluating Vehicle Traction Performance Maximum Speed Acceleration Time Maximum grade 5/109 加速時(shí)間評(píng)價(jià)方法 超車(chē)加速時(shí)間 Overtaking acceleration time 以最高檔或次高檔，以 amax加速至某一高速所用的時(shí)間。 ~===γTdtωdγTΔTΔTTtqstqstqCharacteristic of the engine speed in transient condition In transient condition, power and torque all descend about 5%6%. 15/106 外負(fù)荷特性的使用和制作方法 表格法（輔助插值） 曲線族法 數(shù)學(xué)模型法 n1 n2 n3 … … nn Pe1 Pe2 Pe3 … … Pen Tt1 Tt2 Tt3 … … Ttn be1 be2 be3 … … ben tTePntTePFullload characteristic diagram method Interpolation with table Curves Modeling 16/109 )(=?]1,1[??]1,1[?+,.. .... ,+++=3213210xfyxnyTnanananaaTtqmtqmModeling for Full partload characteristic m7 mopt5 17/109 Braking Power ,kW 圖 14 汽油發(fā)動(dòng)機(jī)外特性及部分負(fù)荷特性 tTePntTePCharacteristic of engine speed at full and part load engine speed, r/min Braking Torque, 18/109 333223)11()21(2)21()21(2)23)(11()11()11(])()()([nnmnnmnmnmnnnmnnneneKKKKKKKKKKKKKKnnnnnnPP?????????????????????????Approximation for Full partload characteristic 19/109 傳動(dòng)系功率損失 機(jī)械損失 液力損失 摩擦 潤(rùn)滑油 齒輪傳動(dòng) 副間摩擦 軸承 摩擦 。 5 286 紅旗 CA7228 l85/70HRl4 312177。 6 492 東風(fēng) EQl092 9.⑷ R20 509177。 ? ???? jiwf FFFFFMV driving resistance Rolling resistance Ff: the tire inner part rub causes to loss, this kind of lose performance shows the resistance moment of the wheel motion. 30/109 KNF , mmh,ZF輪胎徑向變形曲線 Tire radius deforming curve auDamping loss 輪胎 /路面接觸 輪胎變形 載荷 遲滯損失 阻力偶 31/109 .= constu a1ZFa1xF1fT1W 1pFr從動(dòng)輪 Driven Wheel 32/109 滾動(dòng)阻力系數(shù) f rolling resistance coefficient 輪胎內(nèi)部因摩擦產(chǎn)生的遲滯損失 表現(xiàn)為 阻礙車(chē)輪運(yùn)動(dòng)的阻力偶 .The damping loses caused by tire inner interrubs are shown as the resistance moment against wheel motion 111111111111WFffWFrafFraFrFrFaFTWFppzppxZfZ???????????令1ZFa1xF1fT1W1pFr 33/109 滾動(dòng)阻力系數(shù) : 車(chē)輪在 一定條件 下，滾動(dòng)所需要推力 Fp1與負(fù)荷 W1之比，即 單位重力的推力 。輪胎從接地受力變形，到離開(kāi)地面后恢復(fù)原狀，存在滯后時(shí)間。子午線輪胎 f 小，天然橡膠 f 低。 ☆ 誘導(dǎo)阻力：空氣升力在水平方向的分力 ，占 7％ 。驅(qū)動(dòng)輪受力分析 (續(xù) ) gfmdtdu)rIm(F wp 12 111 ???Forces on the tracitive tire 56/109 BG1ZF 2ZF1pF 2pFwF dtdum3加速時(shí)車(chē)身受力圖 gfmdtdu)rIm(F wp 12 111 ???