汽车理论第一章.doc

第一章1),2)问的程序：ig4=6.09,3.09,1.71,1.00;ig5=5.56,2.769,1.644,1.00,0.793;i0=5.83;r=0.367;nt=0.85;m1=2000;m2=1800;m=3880;f=0.013;CDA=2.77;If=0.218;Iw1=1.798;Iw2=3.598;L=3.2;a=1.947;hg=0.9;g=9.8;for i=1:341; n(i)=10*(i+59);Tq(i)=-19.313+295.27*n(i)/1000-165.44*(n(i)/1000)2+40.874*(n(i)/1000)3-3.8445*(n(i)/1000)4;endfor i=1:341; for k=1:5; Ft(i,k)=Tq(i)*ig5(k)*i0*nt/r;ua(i,k)=0.377*r*n(i)/(i0*ig5(k);Fc(i,k)=CDA*ua(i,k)2/21.15+m*g*f;M(i,k)=abs(Ft(i,k)-Fc(i,k); endend for i=1:341 %求最大速度 if(M(i,5)=min(M(:,5) uamax=ua(i,5)end end %求最大速度subplot(1,2,1)plot(ua,Ft,ua,Fc,y)title(汽车驱动力-行驶阻力平衡图)%驱动力行驶阻力平衡图xlabel(ua(km/h);ylabel(Ft/N);gtext(Ft1);gtext(Ft2);gtext(Ft3);gtext(Ft4);gtext(Ft5);gtext(Ff+Fw)for i=1:341; %求最大爬坡度的k=1;Fw(i,k)=CDA*ua(i,k)2/21.15;D(i,k)=(Ft(i,k)-Fw(i,k)/(m*g);s(i,k)=(D(i,k)-f*sqrt(1+f2*D(i,k)2)/(1+f2);b(i,k)=asin(s(i,k);I=tan(b);endImax=max(I) %求最大爬坡度的C=Imax/(a/L+hg/L*Imax) %求最大爬坡度相应的附着率for k=1:5; %加速度倒数曲线图 d(k)=1+(Iw1+Iw2)/(m*r2)+If*ig5(k)2*i02*nt/(m*r2);endfor i=1:341; for k=1:5; d(k)=1+(Iw1+Iw2)/(m*r2)+If*ig5(k)2*i02*nt/(m*r2); Ft(i,k)=Tq(i)*ig5(k)*i0*nt/r; ua(i,k)=0.377*r*n(i)/(i0*ig5(k); Fc(i,k)=CDA*ua(i,k)2/21.15+m*g*f; c(i,k)=(Ft(i,k)-Fc(i,k)/(m*d(k);if(c(i,k)0.05) c(i,k)=c(i-1,k);else b(i,k)=c(i,k); Ua(i,k)=ua(i,k);end endendsubplot(1,2,2)plot(Ua,1./b) title(加速度倒数曲线图)xlabel(ua(km/h);ylabel(1/a);gtext(1/a1);gtext(1/a2);gtext(1/a3);gtext(1/a4);gtext(1/a5);运行结果：uamax = 99.0589Imax = 0.3521C =0.4977从二档加速到70km/h的加速时间计算程序：ig5=5.56,2.769,1.644,1.00,0.793;i0=5.83;r=0.367;nt=0.85;m1=2000;m2=1800;m=3880;f=0.013;CDA=2.77;If=0.218;Iw1=1.798;Iw2=3.598;L=3.2;a=1.947;hg=0.9;g=9.8;for i=1:341;for k=1:5; n(i)=10*(i+59); ua(i,k)=0.377*r*n(i)/(i0*ig5(k);endendMAX=max(ua); %求各挡的最大速度MAX_1=MAX(1);MAX_2=MAX(2);MAX_3=MAX(3);MAX_4=MAX(4);delt=1+(Iw1+Iw2)/(m*r2)+If*ig5(k)2*i02*nt/(m*r2);Ua1=MAX_1:0.001:MAX_2;N1=Ua1*ig5(2)*i0/(0.377*r);TQ1=-19.313+295.27*N1/1000-165.44*(N1/1000).2+40.874*(N1/1000).3-3.8445*(N1/1000).4;FT1=TQ1*ig5(2)*i0*nt/r;FC1=CDA.*Ua1.2/21.15+m*g*f;y1=delt*m./(FT1-FC1);t1=trapz(Ua1,y1)/3.6;%第二挡的加速时间Ua2=MAX_2:0.001:MAX_3;N2=Ua2*ig5(3)*i0/(0.377*r);TQ2=-19.313+295.27*N2/1000-165.44*(N2/1000).2+40.874*(N2/1000).3-3.8445*(N2/1000).4;FT2=TQ2*ig5(3)*i0*nt/r;FC2=CDA.*Ua2.2/21.15+m*g*f;y2=delt*m./(FT2-FC2);t2=trapz(Ua2,y2)/3.6;%第三挡的加速时间Ua3=MAX_3:0.001:70;N3=Ua3*ig5(4)*i0/(0.377*r);TQ3=-19.313+295.27*N3/1000-165.44*(N3/1000).2+40.874*(N3/1000).3-3.8445*(N3/1000).4;FT3=TQ3*ig5(4)*i0*nt/r;FC3=CDA.*Ua3.2/21.15+m*g*f