汽车整车性能计算分解

1、6汽车总体性能计算6.1汽车动力性计算6.1.1汽车各档车速计算各挡车速的计算公式如下：rnu0.377(km/h)(61)aiig0式中r汽车滚动半径，r=0.279m；n发动机转速(r/min)；i汽车变速器的传动比，i=3.17；i=2.158；i=1.469；i=1；gg1g2g3g4i主减速器的传动比，i=5.01。00代入相关参数所得结果见表61。表61汽车各档车速n(r/min)Ua1(km/h)Ua2(km/h)Ua(km/h)Ua4(km/h)10006.622919.7287414.2917720.9946112007.9474911.6744817.1501225.193

2、5314009.2720713.6202320.0084829.39246160010.5966515.5659822.8668333.59138180011.9212317.5117225.7251937.79030200013.2458119.4574728.5835441.98922220014.5703921.4032231.44189468949723.3489634.3002550.38707260017.2195525.2947137.1586054.58599280018.5441427.2404640.0169658.78491300019.8687

3、229.1862142.8753162.98383320021.1933031.1319545.73367675178833.0777048.5920271.38168360023.8424635.0234551.4503775.58060380025.1670436.9691954.3087379.77952400026.4916238.9149457.1670883.97844420027.8162040.8606960.02544881407842.8064462.8837992.37629460030.4653744.7521865.

4、7421496.57521480031.7899546.6979368.60050100.77413500033.1145348.6436871.45885104.973056.1.2汽车行驶阻力计算汽车行驶阻力包括：滚动阻力、空气阻力、加速阻力和爬坡阻力。1)滚动阻力滚动阻力计算公式：F=Gf(N)(6-2)f式中G汽车重力,G=14250N；f滚动阻力系数,f=0.015。2)空气阻力空气阻力计算公式：F=CDAua(N)(6-3)w21.25式中C汽车的空气阻力系数,C=0.52；DDA汽车的迎风面积A=2.726m2；U汽车各档车速(km/h)。a代入相关参数有：2.726x0.52x

5、u2a21.25所以，汽车的行驶阻力CAu2Da21.25二14250 x0.015+2.726x0.52xu2a21.25所得结果见表6-2。表6-2汽车各档行驶阻力(Ff+Fw)l(Ff+Fw)2(Ff+Fw)3(Ff+Fw)4216.67595220.06369227.37518243.15261217.96337222.84171233.37026256.08976219.48487226.12483240.45536271.37912221.24044229.91304248.63047289.02069223.23009234.20635257.89559309.01446225.

6、45381239.00475268.25073331.36045227.91161244.30824279.69588356.05864230.60349250.11684292.23105383.10905233.52944256.43052305.85623412.51166236.68947263.24930320.57143444.26648240.08358270.57318336.37664478.37351243.71176278.40215353.27187514.83275247.57402286.73622371.25711553.64420251.67035295.575

7、38390.33236594.80785256.00077304.91964410.49763638.32372260.56525314.76899431.75292684.19180265.36382325.12344454.09822732.41208270.39646335.98298477.53353782.98457275.66317347.34761502.05886835.90927281.16396359.21734527.67420891.18619286.89883371.59217554.37956948.815316.1.3汽车驱动力计算发动机转矩的拟合公式：nnnnT

8、=67.11731x（一）-19.05015x（一）2+1.88322（）30.03392（）4TOC o 1-5 h z HYPERLINK l bookmark28 o Current Document q1000100010001000（6-4）汽车驱动力计算公式：rriTil耳/、zF=g0T(N)(6-5)tr式中r汽车行驶时的滚动半径,r=0.279m；n发动机曲轴转速(r/min)；i汽车变速器各挡传动比；gn传动系效率，n=89.376%；TTi0汽车主减速器传动比。各档驱动力的计算结果见表6-3。表6-3汽车的各档驱动力FtlFtllFtlllFtW2539.55415172

9、8.819511176.84702801.121182863.938231949.646281327.16885903.450543137.181732135.658731453.79179989.647233363.452842289.694391558.647391061.026133546.853472414.545681643.636521118.881223691.419282512.959871710.629311164.485583801.119632587.639171761.465221199.091373879.857642641.240631797.952961223.9

10、29863931.470162676.376221821.870561240.211413959.727772695.612781834.965331249.125483968.334762701.472061838.953871251.840623960.929202696.430671835.522081249.504483941.082842682.920121826.325141243.243803912.301212663.326821812.987531234.164423878.023532639.992041797.103021223.351273841.622782615.2

11、11981780.234661211.868393806.405672591.237681763.914801200.758893775.612632570.275101749.645101191.044993752.417832554.485071738.896461183.728023739.929182545.983331733.109141179.788383741.188302546.840491733.692621180.185586.1.4汽车驱动力-行驶阻力平衡图及最高车速的确定汽车稳速行驶时驱动力、行驶阻力平衡。即：F=F+F(N)tfw(6-6)驱动力行驶阻力平衡图见图6-

12、1。车連Ckn/h)(=二匠空lr二IKT冷图6-1汽车驱动力-行驶阻力平衡图行驶阻力曲线(Ff+Fw-Ua)与四档驱动力曲线(FtW-Ua)的交点所对应的车速即为汽车的最高行驶车速。由图4-1知汽车的最高车速为：109km/h。设计误差iaq105为：9-xlOO%=3.8%三5%，因此满足要求。1056.1.5汽车加速能力计算1）加速度的计算a=dU=Ft（F+F）（6-7）dt5mfw式中a汽车各挡加速度（m/s2）；5汽车旋转质量转换系数；F驱动力（N）；tF风阻力（N）;Wm汽车质量（kg）。并有：5=1+5i2+5（6-8）1g2式中i变速器的速比g1Ii2n55=iT，其中I为飞

13、轮转动惯量，5=0.04；11mr2f11VI55=w，其中I为车轮转动惯量，5=0.03。22mr2w2计算结果如表6-4。表6-4汽车旋转质量换算系数ig3.172.1581.469151.43191.216281.116321.07将表6-4数值带入式6-7中便可求出汽车各档下的加速度，所得结果见表6-5和图6-2。表6-5汽车各档加速度Ua1Ua2Ua3Ua4a1a2a3a46.622919.7287414.2917720.994611.138410.870500.596870.365947.9474911.6744817.1501225.193531.296760.996310.68

14、7600.424579.2720713.6202320.0084829.392461.429921.101740.762740.4710710.5966515.5659822.8668333.591381.539951.188430.823520.5063211.9212317.5117225.7251937.790301.628861.257990.871120.5311533.114533130.4653729.1407827.8162026.4916225.1670423.8424622.517882119.868721817.219551514134&6436846.6979344.7

15、521842.8064440.860693&9149436.9691935.0234533.077703129.1862127.2404625.2947123.348962119.4574771.458856&6005065.7421462.8837960.0254457.1670854.30873514&5920245.7336742.8753140.0169637.1586034.30025312&58354104.9730100.774196.5752192.376298&1773783.9784479.7795275.5806071.3816867.1827562.983835&7849154.5859950.3870746.18814411.692901.695091.703911.717861.735421.755031.775101.794021.810141.821761.827161.824611.812311.788451.751181.698621.255051.261691.273451.289111.307471.327281.347261.366121.382521.395121.402551.403401.396231.379601.352031.31200OOOOOOOOOOO