【正文】 ss is neglected, then the assumption is in the first time, the MV has already had the lowest speed that start need when shift gear. Time of shift gear to determine: If the gear 1st 2nd acceleration curves is intersected, then shift gear 1st to 2nd。 If the acceleration curves of the gear 1st and 2nd is not intersected, then at max engine speed shift the gear 1st to 2nd。 neglect shift gear spending time. (normal distribution t= s) Use of puting acceleration time: to determine MV acceleration ability, tradeoff powertrain。 reasonably choose displacement of the engine. 94/109 3. 利用驅(qū)動(dòng)力－行駛阻力平衡圖確定汽車 爬坡能力 )(cos.AuCmgfFFFFFFadtduaDwfiwftj1152102??????????Its prior condition is a road surface good, except overing the Fw+ Ff ,all drive force is used for overing a grade resistance, namely. Diagram of equilibrium of drive force driving resistance to determine grade ability of MV 其 前提 條件是路面良好，汽車克服 Fw+Ff后的全部力都用于克服 坡道阻力 ，即 95/109 ,)(arcsin)(sinmgFFFFFFmgwftwft?????????? ??????? ????mgFFFarcsintgtgi wft?坡度通常用 i表示 i represents grade usually 96/109 m aximax0ima xumgFF fw ? ))((arcs inmaxmgFFFtgtgi wft???? ?mgFtMV gradient i Speed, km/h 97/109 imax is max sloping gradient for 1st gear. i0max is max sloping gradient for top gear. Objective: decreasing the number of shift on normal slope, which makes the speed of MV slowly down. 速度。換檔，影響汽車的運(yùn)行車經(jīng)常目的是減少通常坡度汽最高檔的最大爬坡度，檔??max0maxiIi?????? ????mg)FF(Farcsintgtgi wftm ax ? 98/109 jiwft FFFFF ????二、動(dòng)力特性圖評(píng)價(jià)汽車動(dòng)力性 unit drive force to evaluate MV tractive performance dtdugmgFFD wt ?? ????Normalized drive force dtdug)if(dtdumgmmgFFmgFF fiwt ?????????drive factor 99/109 dtdugii ???maxma x0ima xufmax1Dmax0DdtdugifD????Characteristic of normalized drive force and its use 汽車動(dòng)力特性圖及其用途 100/109 m axm axm axm axm axm axm axm axm axaxImaxImm axitgffDfDarcsinsincossincosfDfDi????????????????????222112111?To solve imax ,let While MV acceleration, the road must be flatness. . 101/109 汽車功率平衡 MV power balance 汽車在行駛時(shí)驅(qū)動(dòng)力與阻力平衡 發(fā)動(dòng)機(jī) 輸出功率 也與行駛阻力功率平衡 定義： 用縱坐標(biāo)表示功率，橫坐標(biāo)表示車速，將發(fā)動(dòng)機(jī)功率與經(jīng)常遇到的阻力功率對(duì)車速的關(guān)系繪制在直角坐標(biāo)圖上，就得到功率平衡圖。 )dtdumuAuCsinmgucosmgfu(u)dtdum.AuCsinmgcosmgf(PaaDaaTaaDTe360 0761 40360 0360 01360 01521132????????????????FuP ? 102/109 The traction and resistance balances when the MV drives The engine power output also balances with the driving resistance power. Definition: let vertical coordinate as the power, horizontal coordinate as MV speed, draw diagrams of the engine power and the resistance power to coordinate system in the right angle, then get the equilibrium diagram of power. )360 0761 40360 0sin360 0cos(1360 0)sincos(132dtdumuAuCmgumgfuudtdumAuCmgmgfPaaDaaTaaDTe???????????????? 103/109 maxau39。aueP twf PP??IIIIIIIV部分油門開度abCPower, kw Speed ua, km/h Spare power, kw 后備功率 Part gas pedal 104/109 ☆ 檔位不同時(shí)車速的范圍不同 ， 但是功率的大小不變 ， 只是各檔的功率曲線對(duì)應(yīng)的車速位置不同；低檔時(shí)車速低 ， 速度變化區(qū)域窄；高檔時(shí)車速高 ， 所占速度變化區(qū)域大 。 ☆ 滾動(dòng)阻力功率在低速時(shí)為直線 ， 而在高檔時(shí)是二次曲線 ☆ 空氣阻力功率曲線為三次函數(shù) ☆ 在 低速 時(shí)以 滾動(dòng)阻力功率 為主 ， 而在 高速時(shí)以 空氣阻力功率 為主 。 105/109 The MV speed is different as different gears, but the value of the power is constant, is just the position of the power curve of each gear in the coordinate。 because the MV operates at low gear, the speed variety district is narrow。 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汽車后備功率越大，汽車動(dòng)力性越好。 利用后備功率也可確定汽車的爬坡度和加速度。 后備功率定義： Spare power definition The power balance is also used to the engine load rate as MV drives, be advantageous to analyze the fuel economy. 功率平衡也可看出：了解汽車行駛時(shí)的發(fā)動(dòng)機(jī)負(fù)荷率，有利于分析汽車的燃油經(jīng)濟(jì)性。 The spare power is larger, the tractive performance is better. Making use of the spare power can also make sure the gradient of MV slope and accelerations. 107/106 1. 如何利用汽車行駛方程式求輪式汽車的極限加速度 ？ 2. 在計(jì)算汽車動(dòng)力性時(shí)所使用的發(fā)動(dòng)機(jī)功率與計(jì)算汽車燃料經(jīng)濟(jì)性時(shí)所使用的發(fā)動(dòng)機(jī)功率有何不同？ 108/109 gdtdugfgfgdtdumgfmgdtdumFFFmgFmgFFFFmgFFFFFFwifjjwiftjwift????????????????????????????)( 109/109 1. 在計(jì)算汽車動(dòng)力性時(shí)所使用的發(fā)動(dòng)機(jī)功率與計(jì)算汽車燃料經(jīng)濟(jì)性時(shí)所使用的發(fā)動(dòng)機(jī)功率有何不同？ 前者使用的是發(fā)動(dòng)機(jī)的外特性。即 )()( ma xma x nTTnPP tqtqee ?? 或 )(1jwifTe PPPPP ???? ?后者利用阻力功率反推求得發(fā)動(dòng)機(jī)輸出功率 110/109 360 0360 360 0sin360 0cos3ajaDwaiafudtdumPAuCPumgPumgfP???????? 111/109 謝謝觀看 /歡迎下載 BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES. BY FAITH I BY FAITH