1、确定以轻型五档货车的动力性：解：1.绘制汽车驱动力与行驶阻力平衡图Matlab 编写程序如下n=600:4000; r=0.367; nt=0.85; f=0.013; CA=2.77; io=5.83; m=3880; g=9.8;Tq=-19.313+295.27.*n./1000-165.44.*(n./1000).2+40.874.*(n./1000).3-3.8445.*(n./1000).4;ig1=5.56; Ua1=0.377.*r.*n./(ig1.*io); Ft1=Tq.*ig1.*io.*nt./r;ig2=2.769; Ua2=0.377.*r.*n./(ig2.*i
2、o); Ft2=Tq.*ig2.*io.*nt./r;ig3=1.644; Ua3=0.377.*r.*n./(ig3.*io); Ft3=Tq.*ig3.*io.*nt./r;ig4=1.00; Ua4=0.377.*r.*n./(ig4.*io); Ft4=Tq.*ig4.*io.*nt./r;ig5=0.793; Ua5=0.377.*r.*n./(ig5.*io); Ft5=Tq.*ig5.*io.*nt./r;Fr=m.*g.*f+(CA/21.15).*Ua5.2;plot(Ua1,Ft1,Ua2,Ft2,Ua3,Ft3,Ua4,Ft4,Ua5,Ft5,Ua5,Fr);0 20 4
3、0 60 80 100 12002000400060008000100001200014000Ua(Km/h)Ft(KN)倒 倒 倒 倒 倒 倒 倒 倒 倒 倒2.求最高车速，最大爬坡度及相应附着率2.1 最高车速 Uamaxfunction Uamax=Uamax(Ua5)r=0.367; nt=0.85; f=0.013; CA=2.77; io=5.83; m=3880; g=9.8;ig5=0.793; n=Ua5.*ig5.*io./(0.377.*r);Tq=-19.313+295.27.*n./1000-165.44.*(n./1000).2+40.874.*(n./1000).
4、3-3.8445.*(n./1000).4;Ft5=Tq.*ig5.*io.*nt./r;Fr=m.*g.*f+(CA/21.15).*Ua5.2;Uamax=Ft5-Fr; x=fzero(Uamax,99)x =99.08342.2 最大爬坡度 imaxr=0.367; nt=0.85; f=0.013; CA=2.77; io=5.83; m=3880; g=9.8;Tq=-19.313+295.27.*n./1000-165.44.*(n./1000).2+40.874.*(n./1000).3-3.8445.*(n./1000).4;ig1=5.56; Ua1=0.377.*r.*n
5、./(ig1.*io); i=(Tq.*ig1.*io.*nt./r-m.*g.*f)./(m.*g);imax=m imaximax =0.33252.3 该爬坡度时的附着率 Co a=1.947; L=3.2; hg=0.9; q=0.3325;Co=q./(a./L+hg.*q./L)Co =0.47373.绘制加速度倒数曲线，计算二档起步加速至 70Km/s 的时间Matlab 编写程序如下n=600:4000; r=0.367; nt=0.85; f=0.013; CA=2.77; io=5.83; m=3880; g=9.8; Iw1=1.798; Iw2=3.598; If=0.
6、218;Tq=-19.313+295.27.*n./1000-165.44.*(n./1000).2+40.874.*(n./1000).3-3.8445.*(n./1000).4;ig1=5.56; Ua1=0.377.*r.*n./(ig1.*io); inv_a1=(m+(Iw1+Iw2)./r.2+(If.*ig1.2.*io.2.*nt)./r.2)./(Tq.*ig1.*io.*nt./r-m.*g.*f-(CA./21.15).*Ua1.2);ig2=2.769; Ua2=0.377.*r.*n./(ig2.*io); inv_a2=(m+(Iw1+Iw2)./r.2+(If.*
7、ig2.2.*io.2.*nt)./r.2)./(Tq.*ig2.*io.*nt./r-m.*g.*f-(CA./21.15).*Ua2.2);ig3=1.644; Ua3=0.377.*r.*n./(ig3.*io); inv_a3=(m+(Iw1+Iw2)./r.2+(If.*ig3.2.*io.2.*nt)./r.2)./(Tq.*ig3.*io.*nt./r-m.*g.*f-(CA./21.15).*Ua3.2);ig4=1.00; Ua4=0.377.*r.*n./(ig4.*io); inv_a4=(m+(Iw1+Iw2)./r.2+(If.*ig4.2.*io.2.*nt)./r
8、.2)./(Tq.*ig4.*io.*nt./r-m.*g.*f-(CA./21.15).*Ua4.2);ig5=0.793; Ua5=0.377.*r.*n./(ig5.*io); inv_a5=(m+(Iw1+Iw2)./r.2+(If.*ig5.2.*io.2.*nt)./r.2)./(Tq.*ig5.*io.*nt./r-m.*g.*f-(CA./21.15).*Ua5.2);axis(0 80 0 10);plot(Ua1,inv_a1,Ua2,inv_a2,Ua3,inv_a3,Ua4,inv_a4,Ua5,inv_a5);0 10 20 30 40 50 60 70 800123
9、45678910Ua(Km/h)inva倒倒倒倒倒倒倒求加速时间 tr=0.367;io=5.83;n1=4000;nt=0.85;ig=5.56 2.769 1.644 1.00 0.793;If=0.218;Iw1=1.798;Iw2=3.598;m=3880;g=9.8;f=0.013;CA=2.77;for i=1:2Ua=0.377.*r.*n1./(io.*ig(i):0.00001:0.377.*r.*n1./(io.*ig(i+1);n=Ua.*io.*ig(i+1)./(0.377.*r);Tq=-19.313+295.27.*(n./1000)-165.44.*(n./10
10、00).2+40.874.*(n./1000).3-3.8445.*(n./1000).4;Ft=Tq.*ig(i+1).*io.*nt./r;Fw=m.*g.*f+(CA./21.15).*Ua.2;p=1+(Iw1+Iw2+If.*ig(i+1).2.*io.2.*nt)./(m.*r.2);inv_a=p.*m./(Ft-Fw);s=0;s=s+trapz(Ua,inv_a);endUa=0.377.*r.*n1./(io.*ig(3):0.00001:70;n=Ua.*io.*ig(4)./(0.377.*r);Tq=-19.313+295.27.*(n./1000)-165.44.*(n./1000).2+40.874.*(n./1000).3-3.8445.*(n./1000).4;Ft=Tq.*ig(4).*io.*nt./r;Fw=m.*g.*f+(CA./21.15).*Ua.2;Iw1=1.798;Iw2=3.598;p=1+(Iw1+Iw2+If.*ig(4).2.*io.2.*nt)./(m.*r.2);inv_a=p.*m./(Ft-Fw);acctime=(s+trapz(Ua,inv_a)./3.6acctime =19.64950.4737
