1.3、1）绘制汽车驱动力与行驶阻力平衡图。

2）求汽车的最高车速、最大爬坡度及克服该坡度时相应的附着率。

3）绘制汽车行驶加速倒数曲线，用图解积分法求汽车有Ⅱ档起步加速行驶至70km/h的车速－时间曲线，或者用计算机求汽车用Ⅱ档起步加速至70km/h的加速时间。

n_min=600;n_max=4000;m1=2000;m2=1800;mz=3880;g=9.81;r=0.367;CdA=2.77;f=0.013;nT=0.85;ig=[5.562.7691.6441.00];i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;Iw=2*Iw1+4*Iw2;L=3.2;a=1.947;b=L-a;hg=0.9;g=9.8;1）绘制汽车驱动力与行驶阻力平衡图：for i=1:3401n(i)=599+i;Ttq(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 j=1:4for i=1:3401Ft(i,j)=Ttq(i)*ig(j)*i0*nT/r;ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Fz(i,j)=CdA*ua(i,j)^2/21.15+mz*g*f;endendplot(ua,Ft,ua,Fz),gridtitle('汽车驱动力与行驶阻力平衡图');xxxxxx('ua(km/h)');yyyyyy('Ft(N)');2）①汽车的最高车速：②最大爬坡度：for k=1:1000n1(k)=1800+k*0.5;Ttq(k)=-19.313+295.27*(n1(k)/1000)-165.44*(n1(k)/1000)^2+40.874*(n1(k)/1000)^3-3.8445*(n1(k)/1000)^4; Ft(k)=Ttq(k)*ig(1)*i0*nT/r;ua(k)=0.377*r*n1(k)/(ig(1)*i0);Fz(k)=CdA*ua(k)^2/21.15+mz*g*f;af(k)=asin((Ft(k)-Fz(k))/(mz*g));endfor k=1:1000if(af(k)==max(af))i=tan(af(k));disp('汽车最大爬坡度=');disp(i);endend汽车最大爬坡度=0.3522③相应的附着率：3）①绘制汽车行驶加速倒数曲线:n=(n_min:1:n_max);N=n./1000;Tq=-19.313+295.27*N-165.44*N.^2+40.874*N.^3-3.8445*N.^4;Ft1=Tq*ig(1)*i0*nT/r;Ft2=Tq*ig(2)*i0*nT/r;Ft3=Tq*ig(3)*i0*nT/r;Ft4=Tq*ig(4)*i0*nT/r;ua1=0.377*n*r/ig(1)/i0;ua2=0.377*n*r/ig(2)/i0;ua3=0.377*n*r/ig(3)/i0;ua4=0.377*n*r/ig(4)/i0;Fw1=CdA*ua1.^2/21.15;Fw2=CdA*ua2.^2/21.15;Fw3=CdA*ua3.^2/21.15;Fw4=CdA*ua4.^2/21.15;Ff=mz*g*f;deta1=1+Iw/(mz*r^2)+If*ig(1)^2*i0^2*nT/(mz*r^2); deta2=1+Iw/(mz*r^2)+If*ig(2)^2*i0^2*nT/(mz*r^2); deta3=1+Iw/(mz*r^2)+If*ig(3)^2*i0^2*nT/(mz*r^2); deta4=1+Iw/(mz*r^2)+If*ig(4)^2*i0^2*nT/(mz*r^2); a1=(Ft1- Fw1- Ff)/(deta1*mz);a2=(Ft2- Fw2- Ff)/(deta2*mz);a3=(Ft3- Fw3- Ff)/(deta3*mz);a4=(Ft4- Fw4- Ff)/(deta4*mz);x1=1./a1;x2=1./a2;x3=1./a3;x4=1./a4;plot(ua1,x1,'k', ua2,x2, 'b',ua3,x3,'r',ua4,x4,'y'),grid title('加速度倒数曲线');xxxxxx('ua(km/h)');yyyyyy('1/a');②汽车用Ⅱ档起步加速至70km/h的加速时间2.7、计算与绘制题1中货车的1）汽车功率平衡图；2）最高档与次高档的等速百公里油耗曲线。

m1=2000;m2=1800;mz=3880;g=9.81;r=0.367;CdA=2.77;f=0.013;nT=0.85;ig=[5.562.7691.6441.00];i0=5.83; If=0.218;Iw1=1.798;Iw2=3.598;n1=[815120716142012 2603300634033804];Iw=2*Iw1+4*Iw2;Qid=0.299;L=3.2;a=1.947;b=L-a;hg=0.9;g=9.8;1）汽车功率平衡图：for j=1:4for i=1:3401n(i)=599+i;Ttq(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;Pe(i)=n(i)*Ttq(i)/9549;ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Pz(i,j)=(mz*g*f*ua(i,j)/3600.+CdA*ua(i,j)^3/76140.)/nT;endendplot(ua,Pe,ua,Pz),grid;title('功率平衡图');xxxxxx('ua(km/h)');yyyyyy('Pe,Pz(kw)');for i=1:8Td(i)=-19.313+295.27*(n1(i)/1000.0)-165.44*(n1(i)/1000.0)^2+40.874*(n1(i)/1000.0)^3-3.8445*(n1(i)/1000.0)^4; Pd(i)=n1(i)*Td(i)/9549;u3(i)=0.377*n1(i)*r/(ig(3)*i0);u4(i)=0.377*n1(i)*r/(ig(4)*i0);endb(1)=0.17768*Pd(1)^4-5.8629*Pd(1)^3+72.379*Pd(1)^2-416.46*Pd(1)+1326.8;b(2)=0.043072*Pd(2)^4-2.0553*Pd(2)^3+36.657*Pd(2)^2-303.98*Pd(2)+1354.7;b(3)=0.0068164*Pd(3)^4-0.51184*Pd(3)^3+14.524*Pd(3)^2-189.75*Pd(3)+1284.4;b(4)=0.0018555*Pd(4)^4-0.18517*Pd(4)^3+7.0035*Pd(4)^2-121.59*Pd(4)+1122.9;b(5)=0.00068906*Pd(5)^4-0.091077*Pd(5)^3+4.4763*Pd(5)^2-98.893*Pd(5)+1141.0;b(6)=0.00035032*Pd(6)^4-0.05138*Pd(6)^3+2.8593*Pd(6)^2-73.714*Pd(6)+1051.2;b(7)=0.00028230*Pd(7)^4-0.047449*Pd(7)^3+2.9788*Pd(7)^2-84.478*Pd(7)+1233.9;b(8)=-0.000038568*Pd(8)^4-0.00075215*Pd(8)^3+0.71113*Pd(8)^2-45.291*Pd(8)+1129.7;for i=1:8Qs3(i)=Pd(i)*b(i)/(1.02*u3(i)*7.15);Qs4(i)=Pd(i)*b(i)/(1.02*u4(i)*7.15);endplot(u3,Qs3, '*'),grid;hold on;plot(u4,Qs4, '>');title('3档4档等速百公里油耗图');xxxxxx('u(km/h)');yyyyyy('Qs(L/100km)');3、改变1.3题中轻型货车的主减速器传动比，作出i0为5.17、5.43、5.83、6.17、6.33时的燃油经济性——加速时间曲线，讨论不同i0值对汽车性能的影响和采用不同变速器对汽车性能的影响。

（以最高档，较高转速（n取3403r/min），最经济负荷（即90%负荷大约60Kw）行驶时的油耗）：m1=2000;m2=1800;mz=3880;g=9.81;r=0.367;CdA=2.77;f=0.013;nT=0.85;ig=[5.562.7691.6441.00];i0=[5.175.435.836.17 6.33];If=0.218;Iw1=1.798;Iw2=3.598;Iw=2*Iw1+4*Iw2;n=3403;Qid=0.299;Pe=60;b=0.00028230*Pe^4-0.047449*Pe^3+2.9788*Pe^2-84.478*Pe+1233.9;for i=1:5ua(i)=0.377*n*r/ig(4)/i0(i);Qs(i)=Pe*b/(1.02*ua(i)*7.15);enddisp('百公里消耗燃油=');disp(Qs);disp('L');百公里消耗燃油=26.9678 28.3240 30.4105 32.1840 33.0186 Lfor q=1:5for i=1:3401n(i)=599+i;Ttq(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=1:3401deta=1+Iw/(mz*r^2)+If*ig(4)^2*i0(q)^2*nT/(mz*r^2);ua(i)=0.377*r*n(i)/(ig(4)*i0(q));a(i)=(Ttq(i)*ig(4)*i0(q)*nT/r-CdA*ua(i)^2/21.15-mz*g*f)/(deta*mz);b1(i)=a(i);b(i)=1/b1(i);endfor i=1:3401if(ua(i)<=96.6)m=i;endendt=ua(1)*b(1);for p=2:mt1(p)=(ua(p)-ua(p-1))*(b(p)+b(p-1))*0.5;t=t+t1(p);endtz=t/3.6;disp('加速时间=');disp(tz);disp('s');end加速时间=135.3100 121.7714 101.9921 80.7631 73.8296 st=[135.100121.7714101.9921 80.7631 73.8296]Qs=[26.967828.324030.410532.184033.0186]plot(Qs,t,'r'),grid;hold onplot(Qs,t,'*');title('燃油经济性—加速时间曲线');axis([253550150])xxxxxx('Qs(L)');yyyyyy('t(s)');。