某重型卡车最高车速计算

1、最高车速计算车型说明：北汽有限北京牌 /6x4/336PS/ 牵引车 /F12 变速器/12.00R20 轮胎/ 双减桥4.266 基本参数：整备质量 9660kg 允许最大总重量 G=100000kg=980000N 发动机：潍柴 WP10.336，336PS/2200RPM，1250NM/1200-1600RPM 变速器： 12JSD160T速比表 (r g)档位121110987654321R2R1速比1.001.281.642.102.713.484.465.737.339.3912.0815.533.3314.86中后桥：速比 r 0=4.266轮胎： 12.00R20，滚动半径 =

2、Fd/(2 )=1.125*3.05/(2*3.14)=0.546m其中： F为计算常数，子午胎 =3.05 ，斜交胎 =2.99 ，d为自由直径。 总传动效率 T=0.83 空气阻力系数 CD=0.7 迎风面积 A=7.8m2根据汽车行驶方程式，当车辆的最大驱动力与其受到的总阻力平衡时，车辆达到最大 车速。即Ft =Ff +Fw+Fi +Fj式中 Ft 汽车驱动力， N；Ff 滚动阻力， N，Ff =fG，f=0.0076+0.000056V a(式中 f 为滚动阻力系数， G为 车辆重量， Va为行驶速度)；FW 空气阻力， N；Fi 坡度阻力， N，求最大车速时设汽车在水平路面行驶，故

3、Fi=0；Fj 加速阻力， N，求最大车速时设汽车加速度为零，故 Fj=0。 因此汽车在相应车况达到最大车速时行驶方程式可改写为：Ft=Ff+Fw Mpi gi 0t/r = fG+C dAVa2/21.15 Mpi gi 0t/r = (0.0076+0.000056Va)G+ CdAVa2/21.15式中 Mp 发动机输出扭矩， Nm从发动机万用特性可读出下表：转速 rpm220021002000190018001700160015001400130012001100扭矩 Nm107411091153119012141237125612961296129913001250i g 变速器传动

4、比，直接档 =1，11 档=1.28 ；i 0 主减速器传动比， =4.266 ；t 传动系总效率， 0.83；r 车轮滚动半径， m，按 12.00-20 轮胎， r=Fd/（2 ）=3.05*1.125/2/3.14=0.546G 汽车总重量， N，100t=980000NCd 空气阻力系数，取 0.7A 迎风面积， m2，北京牌重卡车约为 7.8 m2Va 行驶速度， km/h，=0.377rn/ （i g i 0），式中， r 轮胎滚动半径， m；n发动机转速， rpm； i g 变速器速比； i 0驱动桥速比。计算驱动力和阻力如下表：最高档（ r g =1 ）时rgr0GMPnVFt

5、FwFfFw+FfFt-(F w+Ff )14.26698000010742200106.1546964.830992909.0682913273.7216182.79-9217.96214.26698000011092100101.3297191.804072650.6180113008.9215659.54-8467.73314.2669800001153200096.50357477.141652404.1886712744.1115148.3-7671.1614.2669800001190190091.67837717.084622169.7802712479.3114649.09-6

6、932.00314.2669800001214180086.85327872.72331947.3928212214.514161.89-6289.17114.2669800001237170082.0288021.877031737.0263111949.713686.72-5664.84514.2669800001256160077.20288145.090991538.6807511684.8913223.57-5078.4814.2669800001296150072.37768404.488791352.3561311420.0812772.44-4367.95214.2669800

7、001296140067.55258404.488791178.0524511155.2812333.33-3928.84314.2669800001299130062.72738423.943631015.7697110890.4711906.24-3482.314.2669800001300120057.90218430.42857865.50792110625.6711491.18-3060.74714.2669800001250110053.07698106.18132727.26707210360.8611088.13-2981.94814.2669800001150100048.2

8、5187457.68681601.04716710096.0610697.1-3239.41714.26698000099090043.42666420.0956486.8482059831.25110318.1-3898.003次高档( r g =1.28 )时rgr0GMPnVFtFwFfFw+FfFt-(F w+Ff)1.284.2669800001074220082.938914.981775.4411999.213774.64-4859.71.284.2669800001109210079.169205.511617.6811792.313409.98-4204.51.284.266

9、9800001153200075.399570.741467.2711585.413052.67-3481.91.284.2669800001190190071.629877.871324.1911378.5112702.7-2824.81.284.2669800001214180067.8510077.091188.4511171.6112360.06-22831.284.2669800001237170064.08102681060.0510964.7112024.76-1756.81.284.2669800001256160060.3110425.72938.9910757.811169

10、6.8-1271.11.284.2669800001296150056.5510757.75825.5610551.4611377.02-619.31.284.2669800001296140052.7810757.75719.1510344.5711063.72-3061.284.2669800001299130049.0110782.65620.0910137.6710757.7624.91.284.2669800001300120045.2410790.95528.369930.7710459.13331.81.284.2669800001250110041.4710375.91443.979723.8710167.84208.11