汽车理论图形MATLAB程序

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汽车理论习题Matlab程序

汽车理论习题Matlab程序

1.3 确定一轻型货车的动力性能(货车可装用4挡或5挡变速器,任选 其中的一种进行整车性能计算):1)绘制汽车驱动力和行驶阻力平衡图。

2)求汽车最高车速,最大爬坡度及克服该坡度时相应的附着率。

3)绘制汽车行驶加速度倒数曲线,用图解积分法求汽车用2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2档起步加速行驶至70km/h 的加速时间。

轻型货车的有关数据:汽油发动机使用外特性的Tq-n 曲线的拟合公式为23419.313295.27()165.44()40.874() 3.8445()1000100010001000q n n n n T =-+-+- 式中,Tq 为发动机转矩(N•m );n 为发动机转速(r/min )。

发动机的最低转速n min =600r/min,最高转速n max =4000r/min 。

装载质量 2000kg整车整备质量 1800kg总质量 3880kg车轮半径 0.367m传动系机械效率 ηt =0.85滚动阻力系数 f =0.013空气阻力系数×迎风面积 C D A =2.77m 2主减速器传动比 i 0=5.83飞轮转动惯量 I f =0.218kg•m 2二前轮转动惯量 I w1=1.798kg•m 2四后轮转动惯量 I w2=3.598kg•m 2变速器传动比 ig(数据如下表)轴距L=3.2m质心至前轴距离(满载)a=1.974m质心高(满载)hg=0.9m解:Matlab程序:(1) 求汽车驱动力和行驶阻力平衡图和汽车最高车速程序:n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/i0;ua=[0:5:120];Ff=G*f;Fw=CDA*ua.^2/21.15;Fz=Ff+Fw;plot(ua1,Ft1,ua2,Ft2,ua3,Ft3,ua4,Ft4,ua5,Ft5,ua,Fz);title('驱动力-行驶阻力平衡图');xlabel('ua(km/s)');ylabel('Ft(N)');gtext('Ft1'),gtext('Ft2'),gtext('Ft3'),gtext('Ft4'),gtext('Ft5'),gtext('Ff+Fw'); zoom on;[x,y]=ginput(1);zoom off;disp('汽车最高车速=');disp(x);disp('km/h');汽车最高车速=99.3006km/h(2)求汽车最大爬坡度程序:n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;Ft1=Tq*ig(1)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;Ff=G*f;Fw1=CDA*ua1.^2/21.15;Fz1=Ff+Fw1;Fi1=Ft1-Fz1;Zoom on;imax=100*tan(asin(max(Fi1/G)));disp('汽车最大爬坡度=');disp(imax);disp('%');汽车最大爬坡度=35.2197%(3)求最大爬坡度相应的附着率和求汽车行驶加速度倒数曲线程序:clearn=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/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;Fw5=CDA*ua5.^2/21.15;Ff=G*f;deta1=1+(Iw1+Iw2)/(m*r^2)+(If*ig(1)^2*i0^2*nT)/(m*r^2); deta2=1+(Iw1+Iw2)/(m*r^2)+(If*ig(2)^2*i0^2*nT)/(m*r^2); deta3=1+(Iw1+Iw2)/(m*r^2)+(If*ig(3)^2*i0^2*nT)/(m*r^2); deta4=1+(Iw1+Iw2)/(m*r^2)+(If*ig(4)^2*i0^2*nT)/(m*r^2); deta5=1+(Iw1+Iw2)/(m*r^2)+(If*ig(5)^2*i0^2*nT)/(m*r^2); a1=(Ft1-Ff-Fw1)/(deta1*m);ad1=1./a1;a2=(Ft2-Ff-Fw2)/(deta2*m);ad2=1./a2;a3=(Ft3-Ff-Fw3)/(deta3*m);ad3=1./a3;a4=(Ft4-Ff-Fw4)/(deta4*m);ad4=1./a4;a5=(Ft5-Ff-Fw5)/(deta5*m);ad5=1./a5;plot(ua1,ad1,ua2,ad2,ua3,ad3,ua4,ad4,ua5,ad5);axis([0 99 0 10]);title('汽车的加速度倒数曲线');xlabel('ua(km/h)');ylabel('1/a');gtext('1/a1');gtext('1/a2');gtext('1/a3');gtext('1/a4');gtext('1/a5'); a=max(a1);af=asin(max(Ft1-Ff-Fw1)/G);C=tan(af)/(a/L+hg*tan(af)/L);disp('假设后轮驱动,最大爬坡度相应的附着率=');disp(C);假设后轮驱动,最大爬坡度相应的附着率=0.4219(4) >>clearnT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;L=3.2;a=1.947;hg=0.9;m=3880;g=9.8; G=m*g; ig=[5.56 2.769 1.644 1.00 0.793];nmin=600;nmax=4000;u1=0.377*r*nmin./ig/i0;u2=0.377*r*nmax./ig/i0;deta=0*ig;for i=1:5deta(i)=1+(Iw1+Iw2)/(m*r^2)+(If*(ig(i))^2*i0^2*nT)/(m*r^2);endua=[6:0.01:99];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;Ff=G*f;Fw=CDA*ua.^2/21.15;for i=1:Nk=i;if ua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(4)n=ua(i)*(ig(4)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(4)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elsen=ua(i)*(ig(5)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(5)*i0*nT/r;inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;enda=delta(1:k);t(i)=sum(a);endplot(t,ua);axis([0 80 0 100]);title('汽车2档原地起步换挡加速时间曲线');xlabel('时间t(s)');ylabel('速度ua(km/h)');>> ginputans =25.8223 70.073725.7467 70.0737所以汽车2档原地起步换挡加速行驶至70km/h 的加速时间约为25.8s2.7已知货车装用汽油发动机的负荷特性和万有特性。

汽车理论课后题matlab程序

汽车理论课后题matlab程序

n=600:1:4000; r=; i0=; eff=; f=;m=3880; g=; G=m*g; CdA=; a=; hg=; L=;Iw1=; Iw2=; Iw=Iw1+Iw2; If=;Ttq=+*n/*(n/1000).^2+*(n/1000).^*(n/1000).^4;%驱动力行驶阻力平衡图for ig=[,,,,]Ua=*r*n/ig/i0;Ft=Ttq*ig*i0*eff/r;plot(Ua,Ft);hold on;endFf=G*f;ua=0::max(Ua);Fw=CdA*ua.^2/;plot(ua,(Ff+Fw)); title('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') [x,y]=ginput(1); disp('汽车的最高车速');disp(x);disp('km/h');%最大爬坡度及最大爬坡度时的附着率Ua=*r*n/i0;Ft=Ttq**i0*eff/r;Fw=CdA*Ua.^2/;i=tan(asin((Ft-(Ff+Fw))/G));disp('汽车的最大爬坡度');disp(max(i));C=max(i)/(a/L+hg/L*max(i));disp('克服最大爬坡度时的附着率');disp(C);%加速度倒数曲线figure;for ig=[,,,,]Ua=*r*n/ig/i0;q=1+Iw/(m*r^2)+If*ig^2*i0^2*eff/(m*r^2);Ft=Ttq*ig*i0*eff/r;Fw=CdA*Ua.^2/;as=(Ft-(Ff+Fw))/q/m;plot(Ua,1./as);hold on;endaxis([0 98 0 10]);title('行驶加速度倒数曲线');xlabel('Ua/(km/h)');ylabel('1/a');gtext('1/a1'),gtext('1/a2'),gtext('1/a3'),gtext('1/a4'),gtext('1/a5'); %加速时间曲线u(1)=*r*600/i0/;dt=;w=1;t(1)=0;ig=;while(u(w)<n(w)=u(w)*ig*i0/r;Ttq(w)=+*n(w)/*(n(w)/1000)^2+*(n(w)/1000)^*(n(w)/1000)^4;Ft(w)=Ttq(w)*ig*i0*eff/r;Ff=G*f;Fw(w)=CdA*u(w)^2/;q=1+Iw/(m*r^2)+If*ig^2*i0^2*eff/(m*r^2);a(w)=*(Ft(w)-(Ff+Fw(w)))/q/m;u(w+1)=u(w)+a(w)*dt;if(u(w+1)>=*4000*r/i0)ig=;endif(u(w+1)>=*4000*r/i0) ig=; endif(u(w+1)>=*4000*r/i0) ig=; endt(w+1)=(w+1)*dt; w=w+1; endfigure;plot(t,u);axis([0 60 0 100]);title('2挡原地起步加速时间曲线');xlabel('时间t/s'),ylabel('车速u/(km/h)');[x1,y1]=ginput(1);disp('加速到70km/h 的时间');disp(x1);0204060801001202000400060008000100001200014000驱动力-行驶阻力平衡图Ua/(km/h)F t /N102030405060708090012345678910行驶加速度倒数曲线Ua/(km/h)1/a10203040506001020304050607080901002挡原地起步加速时间曲线时间t/s车速u /(k m /h)Iw1=; Iw2=; Iw=Iw1+Iw2; If=; m=1600; g=;G=m*g; Ttqmax=140; i1=; i0=; eff=; r=; hg=; b=; L=; q=1+Iw/(m*r^2)+If*i1^2*i0^2*eff/(m*r^2); Ft=Ttqmax*i1*i0*eff/r;a=Ft/q/m;q=a/g;C1=q/(b/L-hg/L*q);if(C1>disp('发动机转矩不能充分发挥');elsedisp('发动机转矩能够充分发挥');endb=(q/+hg/L*q)*L;disp('调整后的b值');disp(b);disp('调整后的前轴负荷率'),disp(b/L);Iw=; If=; m=2152; g=; r=; eff=; i4=1; i0=;amax=; Ua=50/; CdA=;q=1+Iw/(m*r^2);f=q*g;disp('汽车在该路面上的滚动阻力系数');disp(f);q=1+Iw/(m*r^2)+If*i4^2*i0^2*eff/(m*r^2);D4max=f+q*amax/g;disp('最大动力因数');disp(D4max);Fw=CdA*Ua^2/;D1max=(D4max*G+Fw)*i1/i4/G;imax=tan(asin((D1max-f*sqrt(1-D1max^2+f^2))/(1+f^2))); disp('最大爬坡度'),disp(imax);n=600:1:4000; r=; i0=; eff=; f=;CdA=;m=3880; g=; G=m*g;Ttq=+*n/*(n/1000).^2+*(n/1000).^*(n/1000).^4;for ig=[,,,,]Ua=*r*n/ig/i0;Pe=Ttq.*n/9550;plot(Ua,Pe);hold on;endUa=0::max(Ua);Pf=G*f*Ua/3600;Pw=CdA*Ua.^3/76140;plot(Ua,(Pf+Pw)/eff);title('汽车的功率平衡图'),xlabel('Ua/(km/h)'),ylabel('P/kw');%等速百公里燃油消耗n1=[815,1207,1614,2012,2603,3006,3403,3804];b0=[,,,,,,,];b1=[,,,,,,,] ;b2=[,,,,,,,];b3=[,,,,,,,];b4=[,,,,,,,];B0=spline(n1,b0,n); B1=spline(n1,b1,n); B2=spline(n1,b2,n); B3=spline(n1,b3,n); B4=spline(n1,b4,n);deng=7;figure;for ig=[,]Ua=*r*n/ig/i0;Pf=G*f*Ua/3600;Pw=CdA*Ua.^3/76140;P=(Pf+Pw)/eff;b=B0+B1.*P+B2.*P.^2+B3.*P.^3+B4.*P.^4; Q=P.*b./*Ua*deng); plot(Ua,Q); hold on; endaxis([0 100 12 28]);title('最高挡与次高挡等速百公里油耗曲线'),xlabel('Ua/(km/h)'),ylabel('百公里油耗Qs/(L/100km)');204060801001200102030405060708090100汽车的功率平衡图Ua/(km/h)P /k w020406080100121416182022242628最高挡与次高挡等速百公里油耗曲线Ua/(km/h)百公里油耗Q s /(L /100k m )beta=; L=; a1=; b1=L-a1; hg1=; a2=; b2=L-a2; hg2=;g=; z=0::1;faif1=beta*z./(1/L*(b1+z*hg1)); fair1=(1-beta)*z./(1/L*(a1-z*hg1)); faif2=beta*z./(1/L*(b2+z*hg2)); fair2=(1-beta)*z./(1/L*(a2-z*hg2));plot(z,faif1,'r',z,fair1,'g',z,faif2,'b',z,fair2,'k'); fai=0::1;Ef1=(b1/L)./(beta-fai*hg1/L); Er1=(a1/L)./((1-beta)+fai*hg1/L); Ef2=(b2/L)./(beta-fai*hg2/L); Er2=(a2/L)./((1-beta)+fai*hg2/L); figure;plot(fai,Ef1,'r',fai,Er1,'g',fai,Ef2,'b',fai,Er2,'k');axis([0 1 0 1]);fai=;Er1=(a1/L)/((1-beta)+fai*hg1/L);Er2=(a2/L)/((1-beta)+fai*hg2/L);abmax1=fai*Er1*g;abmax2=fai*Er2*g;t21=; t22=; u0=30;s1=1/*(t21+t22/2)*u0+u0^2/abmax1;s2=1/*(t21+t22/2)*u0+u0^2/abmax2;disp('空载时的制动距离'),disp(s1);disp('满载时的制动距离'),disp(s2);%前部管路损坏时制动距离z1=a1*fai/(L+fai*hg1); z2=a2*fai/(L+fai*hg2); abmax1=z1*g; abmax2=z2*g;s1=1/*(t21+t22/2)*u0+u0^2/abmax1;s2=1/*(t21+t22/2)*u0+u0^2/abmax2;disp('前部管路损坏时空载制动距离');disp(s1); disp('前部管路损坏时满载制动距离');disp(s2); %后部管路损坏时的制动距离z1=b1*fai/(L-fai*hg1);z2=b2*fai/(L-fai*hg2); abmax1=z1*g; abmax2=z2*g;s1=1/*(t21+t22/2)*u0+u0^2/abmax1;s2=1/*(t21+t22/2)*u0+u0^2/abmax2;disp('后部管路损坏时空载制动距离');disp(s1); disp('后部管路损坏时满载制动距离');disp(s2);hg=; b=; L=; beta=; fai=; g=;fai0=(L*beta-b)/hg;if(fai<fai0)disp('前轮先抱死,制动效率为'); E=(b/L)/(beta-fai*hg/L);elsedisp('后轮先抱死,制动效率为'); E=(a/L)/((1-beta)+fai*hg/L);enddisp('最大制动减速度'),disp(E*fai*g);disp('a)、b)、c)的双回路制动系统制动系增益都为G');disp('1回路失效时,a)、b)、c)的制动系增益分别为,,');disp('1回路失效时,a)、b)、c)的制动系增益分别为,,');disp('a)中1回路失效时最大制动强度');zmax1=a*fai/(L+fai*hg)disp('a)中1回路失效时制动效率');disp(zmax1/fai)disp('a)中1回路失效时最大制动减速度');abmax1=zmax1*gdisp('a)中2回路失效时最大制动强度');zmax2=a*fai/(L+fai*hg)disp('a)中1回路失效时制动效率');disp(zmax1/fai)disp('a)中2回路失效时最大制动减速度');abmax2=zmax2*gdisp('b)或c)中1或2回路失效时最大制动强度');z=fai*b/(2*L*beta-fai*hg)disp('b)或c)中1或2回路失效时最大制动减速度');abmax=z*gdisp('b)或c)中1或2回路失效时制动效率');disp(z/fai)disp('双回路系统a制动系增益最大,一个回路失效时的最大制动减速度也比b、c大,所以其性能较优')disp('b和c制动系增益相同,两者在一个回路失效时的制动效率相同。

汽车理论作业-Matlab程序-轻型货车动力性能评价

汽车理论作业-Matlab程序-轻型货车动力性能评价

轻型货车动力学性能评价4209XX班姓名:XX 学号:XXXXXXXX 已知条件该轻型货车相关参数如下:装载质量2000kg整车装备质量1800kg总质量(总重G)3800kg(38062.8 N)车轮半径(r)0.367 m传动系机械效率滚动阻力系数 f =0.013空气阻力系数X 迎风面积主减速器传动比飞轮转动惯量二前轮转动惯量四后轮转动惯量轴距质心至前轴的距离(满载)质心高变速器传动比(数据见下表)挡位1挡2挡3挡4挡5挡传动比 5.56 2.769 1.644 1.00 0.793发动机最低转速为 ,最高转速为汽车发动机使用外特性的曲线拟合公式为:驱动力与行驶阻力平衡图车速 [km/h]滚动阻力:空气阻力:行驶阻力:[N]驱动力 :利用matlab 绘出出每一挡的驱动力与行驶阻力平衡图如下:2040608010012002000400060008000100001200014000X: 99.06Y: 1780ua /(km/h )F /N汽车驱动力—行驶阻力平衡图Ft5Ft3Ft4Ft2Ft1最高车速点Fw+Ff图 1汽车驱动力与行驶阻力平衡图最高车速和最大爬坡度最高车速点:图 1汽车驱动力与行驶阻力平衡图中五挡驱动力曲线与行驶阻力曲线的交点。

由驱动力行驶阻力平衡方程:可利用matlab求解出求解出最高车速为:●最大爬坡度的计算最大坡度角满足方程:显然一挡的爬坡度最大,,可求解出但过于复杂,可对上式进行分析可知,当驱动力与空气阻力之差最大时,剩余的驱动力全部用来克服道路阻力,此时爬坡度最大。

可利用matlab先找到该车所能克服的道路阻力的最大值为:13125.7359567165 N那么最大动力因数为从而可求得最大坡度角为那么最大爬坡度为●克服最大爬坡度时相应的附着率计算1.计算静态轴荷的法向反作用力25400.85N2.动态分量3.空气升力由于此时车速很小,空气升力可忽略不计4.滚动阻力偶产生的部分也很小,可忽略不计。

汽车理论MATLAB编程

汽车理论MATLAB编程
Ft=Ttq*ig(2)*io*m/r
ad=(deta(2)*M)./(Ft-Fwf(i))
delta(i)=0.1*ad/3.6
elseif ua(i)<=uamax(3)
n=ua(i)*ig(3)*io/r/0.377
ua=0.377*r*n/ig/io
deta=1+(Iw1+Iw2)/(M*r^2)+If*ig.^2*io^2*m/(M*r^2)%汽车旋转质量换算系数
Fw=CdA/21.15*(ua).^2
Ttq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4
ua=0.377*r*n/ig/io
deta=1+(Iw1+Iw2)/(M*r^2)+If*ig.^2*io^2*m/(M*r^2)%汽车旋转质量换算系数
Fw=CdA/21.15*(ua).^2
Fwf=Fw+Ff
Ttq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4
delta(i)=0.1*ad/3.6
elseif ua(i)<=uamax(4)
n=ua(i)*ig(4)*io/r/0.377
Ttq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4
axis([0,80,0,100])

汽车理论习题Matlab程序

汽车理论习题Matlab程序

1.3 确定一轻型货车的动力性能〔货车可装用4挡或5挡变速器,任选 其中的一种进行整车性能计算〕:1〕绘制汽车驱动力与行驶阻力平衡图。

2〕求汽车最高车速,最大爬坡度及克服该坡度时相应的附着率。

3〕绘制汽车行驶加速度倒数曲线,用图解积分法求汽车用2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2档起步加速行驶至70km/h 的加速时间。

轻型货车的有关数据:汽油发动机使用外特性的Tq-n 曲线的拟合公式为23419.313295.27()165.44()40.874() 3.8445()1000100010001000q n n n n T =-+-+- 式中,Tq 为发动机转矩〔N•m 〕;n 为发动机转速〔r/min 〕。

发动机的最低转速n min =600r/min,最高转速n max =4000r/min 。

装载质量 2000kg整车整备质量 1800kg总质量 3880kg传动系机械效率 ηt滚动阻力系数 f空气阻力系数×迎风面积 C D A 2主减速器传动比 i 0飞轮转动惯量 I f =0.218kg•m 2二前轮转动惯量 I w1=1.798kg•m 2四后轮转动惯量 I w2=3.598kg•m 2变速器传动比 ig(数据如下表)解:Matlab程序:(1) 求汽车驱动力与行驶阻力平衡图和汽车最高车速程序:n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/i0;ua=[0:5:120];Ff=G*f;Fw=CDA*ua.^2/21.15;Fz=Ff+Fw;plot(ua1,Ft1,ua2,Ft2,ua3,Ft3,ua4,Ft4,ua5,Ft5,ua,Fz);title('驱动力-行驶阻力平衡图');xlabel('ua(km/s)');ylabel('Ft(N)');gtext('Ft1'),gtext('Ft2'),gtext('Ft3'),gtext('Ft4'),gtext('Ft5'),gtext('Ff+Fw'); zoom on;[x,y]=ginput(1);zoom off;disp('汽车最高车速=');disp(x);disp('km/h');汽车最高车速=km/h(2)求汽车最大爬坡度程序:n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;Ft1=Tq*ig(1)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;Ff=G*f;Fw1=CDA*ua1.^2/21.15;Fz1=Ff+Fw1;Fi1=Ft1-Fz1;Zoom on;imax=100*tan(asin(max(Fi1/G)));disp('汽车最大爬坡度=');disp(imax);disp('%');汽车最大爬坡度=35.2197%(3)求最大爬坡度相应的附着率和求汽车行驶加速度倒数曲线程序:clearn=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/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;Fw5=CDA*ua5.^2/21.15;Ff=G*f;deta1=1+(Iw1+Iw2)/(m*r^2)+(If*ig(1)^2*i0^2*nT)/(m*r^2); deta2=1+(Iw1+Iw2)/(m*r^2)+(If*ig(2)^2*i0^2*nT)/(m*r^2); deta3=1+(Iw1+Iw2)/(m*r^2)+(If*ig(3)^2*i0^2*nT)/(m*r^2); deta4=1+(Iw1+Iw2)/(m*r^2)+(If*ig(4)^2*i0^2*nT)/(m*r^2); deta5=1+(Iw1+Iw2)/(m*r^2)+(If*ig(5)^2*i0^2*nT)/(m*r^2); a1=(Ft1-Ff-Fw1)/(deta1*m);ad1=1./a1;a2=(Ft2-Ff-Fw2)/(deta2*m);ad2=1./a2;a3=(Ft3-Ff-Fw3)/(deta3*m);ad3=1./a3;a4=(Ft4-Ff-Fw4)/(deta4*m);ad4=1./a4;a5=(Ft5-Ff-Fw5)/(deta5*m);ad5=1./a5;plot(ua1,ad1,ua2,ad2,ua3,ad3,ua4,ad4,ua5,ad5);axis([0 99 0 10]);title('汽车的加速度倒数曲线');xlabel('ua(km/h)');ylabel('1/a');gtext('1/a1');gtext('1/a2');gtext('1/a3');gtext('1/a4');gtext('1/a5'); a=max(a1);af=asin(max(Ft1-Ff-Fw1)/G);C=tan(af)/(a/L+hg*tan(af)/L);disp('假设后轮驱动,最大爬坡度相应的附着率=');disp(C);假设后轮驱动,最大爬坡度相应的附着率=(4) >>clearnT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;L=3.2;a=1.947;hg=0.9;m=3880;g=9.8; G=m*g; ig=[5.56 2.769 1.644 1.00 0.793];nmin=600;nmax=4000;u1=0.377*r*nmin./ig/i0;u2=0.377*r*nmax./ig/i0;deta=0*ig;deta(i)=1+(Iw1+Iw2)/(m*r^2)+(If*(ig(i))^2*i0^2*nT)/(m*r^2);endua=[6:0.01:99];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;Ff=G*f;Fw=CDA*ua.^2/21.15;for i=1:Nk=i;if ua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(4)n=ua(i)*(ig(4)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(4)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elsen=ua(i)*(ig(5)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(5)*i0*nT/r;inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;enda=delta(1:k);t(i)=sum(a);endplot(t,ua);axis([0 80 0 100]);title('汽车2档原地起步换挡加速时间曲线');xlabel('时间t〔s〕');ylabel('速度ua〔km/h〕');>> ginputans =所以汽车2档原地起步换挡加速行驶至70km/h 的加速时间约为s货车装用汽油发动机的负荷特性与万有特性。

汽车理论第四章matlab

汽车理论第四章matlab

第四章1)求利用附着系数曲线的程序:m1=4080;hg1=0.845;L1=3.950;a1=2.100;bt1=0.38;m2=9290;hg2=1.170;L2=3.950;a2=2.950;bt2=0.38;%利用附着系数与制动强度的关系曲线z=0:0.01:0.8;y=z;b1=L1-a1;b2=L2-a2;yf1=bt1*L1.*z./(b1+hg1.*z);yf2=bt2*L2.*z./(b2+hg2.*z);yr1=(1-bt1)*L1.*z./(a1-hg1.*z);yr2=(1-bt2)*L2.*z./(a2-hg2.*z);%ECE法规要求曲线yECE2=(z+0.07)./0.85;z1=0.30:0.01:0.80;yECE1=(z1-0.02)./0.74;z2=0.15:0.01:0.30;yECE3=z2+0.08;yECE4=z2-0.08;plot(z,yf1,'y',z,yf2,'g',z,yr1,'b',z,yr2,'c',z,y,'r--',z,yECE2,'k',z1,yECE1,'k',z2,yECE3,'k',z2,yE CE4,'k')axis([0 0.8 0 0.8]);xlabel('制动强度z/g');ylabel('利用附着系数y');title('利用附着系数与制动强度的关系曲线');gtext('yf1(空车)');gtext('yf2(满载)');gtext('yr1(空车)');gtext('yr2(满载)');gtext('y=z');gtext('ECE法规要求界限')以下是利用附着系数曲线和ECE法规要求曲线界限由利用附着系数曲线和ECE法规要求曲线界限曲线可知该车的制动系统满足法规的要求求制动效率曲线的程序:m1=4080;hg1=0.845;L1=3.950;a1=2.100;bt1=0.38;m2=9290;hg2=1.170;L2=3.950;a2=2.950;bt2=0.38;b1=L1-a1;b2=L2-a2;%求制动效率曲线Y=(0:0.01:1); %Y为地面附着系数Ef1=b1./(bt1*L1-Y*hg1)*100; %空车Ef2=b2./(bt2*L2-Y*hg2)*100; %满载Er1=a1./((1-bt1)*L1+Y*hg1)*100;Er2=a2./((1-bt2)*L2+Y*hg2)*100;plot(Y,Ef1,'y',Y,Ef2,'b',Y,Er1,'k',Y,Er2,'r')axis([0 1.0 0 100]);xlabel('附着系数Y');ylabel('制动效率(%)');title('制动效率曲线')gtext('Ef2(满载)'),gtext('Er1(空车)'),gtext('Ef2(满载)');以下是制动效率曲线:2),3)问的计算程序:m1=4080;hg1=0.845;L1=3.950;a1=2.100;bt1=0.38; m2=9290;hg2=1.170;L2=3.950;a2=2.950;bt2=0.38; b1=L1-a1;b2=L2-a2;%求制动效率曲线Y=(0:0.01:1); %Y为地面附着系数Ef1=b1./(bt1*L1-Y*hg1)*100; %空车Ef2=b2./(bt2*L2-Y*hg2)*100; %满载Er1=a1./((1-bt1)*L1+Y*hg1)*100;Er2=a2./((1-bt2)*L2+Y*hg2)*100;%求制动距离t1=0.02;t2=0.2;ua0=30;Y1=0.8;g=9.8;abmax1=Y1*g*Er1(81)/100;abmax2=Y1*g*Er2(81)/100;disp('空载时汽车不抱死的制动距离')s1=1/3.6*(t1+t2/2)*ua0+ua0^2/(25.92*abmax1) disp('满载时汽车不抱死的制动距离')s2=1/3.6*(t1+t2/2)*ua0+ua0^2/(25.92*abmax2)%当汽车制动系后部管路破损时的制动距离Fxb11=Y1*m1*g*b1/(L1-Y1*hg1); %当后轮的制动力为0,空车时前轮的地面制动力Fxb12=Y1*m2*g*b2/(L2-Y1*hg2); %当后轮的制动力为0,满载时前轮的地面制动力a11=Fxb11/m1;a12=Fxb12/m2;disp('当汽车制动系后部管路破损时空车的制动距离')s11=1/3.6*(t1+t2/2)*ua0+ua0^2/(25.92*a11)disp('当汽车制动系后部管路破损时满载的制动距离')s12=1/3.6*(t1+t2/2)*ua0+ua0^2/(25.92*a12)%当汽车制动系前部管路破损时的制动距离Fxb21=Y1*m1*g*a1/(L1+Y1*hg1); %当前轮的制动力为0,空车时后轮的地面制动力Fxb22=Y1*m2*g*a2/(L1+Y1*hg2); %当前轮的制动力为0,满载时后轮的地面制动力a21=Fxb21/m1;a22=Fxb22/m2;disp('当汽车制动系前部管路破损时空车的制动距离')s21=1/3.6*(t1+t2/2)*ua0+ua0^2/(25.92*a21)disp('当汽车制动系前部管路破损时满载的制动距离')s22=1/3.6*(t1+t2/2)*ua0+ua0^2/(25.92*a22)运行结果为:空载时汽车不抱死的制动距离s1 =7.5906满载时汽车不抱死的制动距离s2 =6.0819当汽车制动系后部管路破损时空车的制动距离s11 =8.8379当汽车制动系后部管路破损时满载的制动距离s12 =14.3486当汽车制动系前部管路破损时空车的制动距离s21 =10.7561当汽车制动系前部管路破损时满载的制动距离s22 =8.3354。

汽车理论课后习题MATLAB编程-武汉理工版

汽车理论课后习题MATLAB编程-武汉理工版

汽车理论课后习题MATLAB编程1.3 确定一轻型货车的动力性能(货车可装用4挡或5挡变速器,任选其中的一种进行整车性能计算):1)绘制汽车驱动力与行驶阻力平衡图。

2)求汽车最高车速,最大爬坡度及克服该坡度时相应的附着率。

3)绘制汽车行驶加速度倒数曲线,用图解积分法求汽车用2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2档起步加速行驶至70km/h的加速时间。

解:(1) 求汽车驱动力与行驶阻力平衡图和汽车最高车速:n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/i0;ua=[0:5:120];Ff=G*f;Fw=CDA*ua.^2/21.15;Fz=Ff+Fw;plot(ua1,Ft1,ua2,Ft2,ua3,Ft3,ua4,Ft4,ua5,Ft5,ua,Fz);title('驱动力-行驶阻力平衡图');xlabel('ua(km/s)');ylabel('Ft(N)');gtext('Ft1'),gtext('Ft2'),gtext('Ft3'),gtext('Ft4'),gtext('Ft5'),gtext('Ff+Fw');zoom on;[x,y]=ginput(1);zoom off;disp('汽车最高车速=');disp(x);disp('km/h');汽车最高车速=99.3006km/h(2)求汽车最大爬坡度程序:n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;Ft1=Tq*ig(1)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;Ff=G*f;Fw1=CDA*ua1.^2/21.15;Fz1=Ff+Fw1;Fi1=Ft1-Fz1;Zoom on;imax=100*tan(asin(max(Fi1/G)));disp('汽车最大爬坡度=');disp(imax);disp('%');汽车最大爬坡度=35.2197%(3)求最大爬坡度相应的附着率和求汽车行驶加速度倒数曲线程序:clearn=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/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;Fw5=CDA*ua5.^2/21.15;Ff=G*f;deta1=1+(Iw1+Iw2)/(m*r^2)+(If*ig(1)^2*i0^2*nT)/(m*r^2);deta2=1+(Iw1+Iw2)/(m*r^2)+(If*ig(2)^2*i0^2*nT)/(m*r^2);deta3=1+(Iw1+Iw2)/(m*r^2)+(If*ig(3)^2*i0^2*nT)/(m*r^2);deta4=1+(Iw1+Iw2)/(m*r^2)+(If*ig(4)^2*i0^2*nT)/(m*r^2);deta5=1+(Iw1+Iw2)/(m*r^2)+(If*ig(5)^2*i0^2*nT)/(m*r^2);a1=(Ft1-Ff-Fw1)/(deta1*m);ad1=1./a1;a2=(Ft2-Ff-Fw2)/(deta2*m);ad2=1./a2;a3=(Ft3-Ff-Fw3)/(deta3*m);ad3=1./a3;a4=(Ft4-Ff-Fw4)/(deta4*m);ad4=1./a4;a5=(Ft5-Ff-Fw5)/(deta5*m);ad5=1./a5;plot(ua1,ad1,ua2,ad2,ua3,ad3,ua4,ad4,ua5,ad5);axis([0 99 0 10]);title('汽车的加速度倒数曲线');xlabel('ua(km/h)');ylabel('1/a');gtext('1/a1');gtext('1/a2');gtext('1/a3');gtext('1/a4');gtext('1/a5');a=max(a1);af=asin(max(Ft1-Ff-Fw1)/G);C=tan(af)/(a/L+hg*tan(af)/L);disp('假设后轮驱动,最大爬坡度相应的附着率=');disp(C);假设后轮驱动,最大爬坡度相应的附着率=0.4219(4) >>clearnT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;L=3.2;a=1.947;hg=0.9;m=3880;g=9.8;G=m*g; ig=[5.56 2.769 1.644 1.00 0.793];nmin=600;nmax=4000;u1=0.377*r*nmin./ig/i0;u2=0.377*r*nmax./ig/i0;deta=0*ig;for i=1:5deta(i)=1+(Iw1+Iw2)/(m*r^2)+(If*(ig(i))^2*i0^2*nT)/(m*r^2);endua=[6:0.01:99];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;Ff=G*f;Fw=CDA*ua.^2/21.15;for i=1:Nk=i;if ua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(4)n=ua(i)*(ig(4)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(4)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elsen=ua(i)*(ig(5)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(5)*i0*nT/r;inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;enda=delta(1:k);t(i)=sum(a);endplot(t,ua);axis([0 80 0 100]);title('汽车2档原地起步换挡加速时间曲线');xlabel('时间t(s)');ylabel('速度ua(km/h)');>> ginputans =25.8223 70.073725.7467 70.0737所以汽车2档原地起步换挡加速行驶至70km/h的加速时间约为25.8s2.7已知货车装用汽油发动机的负荷特性与万有特性。

Matlab程序模拟汽车理论中的数据特性图1

Matlab程序模拟汽车理论中的数据特性图1

车辆理论作业第三组第一大题确定一辆轻型货车的动力性能 1、绘制发动机的使用外特性曲线 n=600:1:4000 N=n/1000T=-19.313+295.27*n/1000-165.44*N.*N+40.874*N.*N.*N-3.8445*N.*N.*N .*NPe=T.*n/9550 %发动机的净功率 figure(1) plot(n,T) xlabel('转速n') ylabel('转矩T') figure(2) plot(n,Pe) xlabel('转速n') ylabel('功率Pe')5001000150020002500300035004000100110120130140150160170180转速n转矩T5001000150020002500300035004000010203040506070转速n功率P e2、绘制驱动力---行驶阻力平衡图 i0=6.17; %减速器的传动比 ig(1)=6.09 % 一档的传动比 ig(2)=3.09 ig(3)=1.71 ig(4)=1.00 nT=0.85 r=0.367 f=0.013 m1=3880 m2=9590 CdA=2.77 Ff1=m1*9.8*f Ff2=m2*9.8*fft1=T*ig(1)*i0*nT/r %一档所产生的驱动力 ft2=T*ig(2)*i0*nT/r ft3=T*ig(3)*i0*nT/r ft4=T*ig(4)*i0*nT/r Ft=[ft1;ft2;ft3;ft4]';ua1=0.377*r*n/(ig(1)*i0) %一档的速度 ua2=0.377*r*n/(ig(2)*i0) ua3=0.377*r*n/(ig(3)*i0) ua4=0.377*r*n/(ig(4)*i0) ua=[ua1;ua2;ua3;ua4]';fw1=CdA*ua1.^2/21.15+Ff1 %一档的行驶阻力 fw2=CdA*ua2.^2/21.15+Ff1 fw3=CdA*ua3.^2/21.15+Ff1 fw4=CdA*ua4.^2/21.15+Ff1Fz1=[fw1;fw2;fw3;fw4]'; figure(3)plot(ua,Ft) %绘制各档的驱动力曲线hold onplot(ua,Fz1) %绘制行驶阻力曲线 hold onplot(ua4,Ff2) %绘制滚动阻力曲线 xlabel('ua/(km.h)')ylabel('F/N')title('汽车驱动力-行驶阻力平衡图')text(20,12000,'Ft1'); text(30,6000,'Ft2'); text(40,4000,'Ft3'); text(80,3000,'Ft4');text(90,2200,'(空载)Ff+fw'); text(105,1450,'满载Ff')102030405060708090200040006000800010000120001400016000ua/(km.h)F /N汽车驱动力-行驶阻力平衡图Ft1Ft2Ft3Ft4(空载)Ff+Fw满载Ff一档的驱动力很大,可用于爬坡且坡度较大;二档用于直接原地起步加速 3、绘制动力特性图D=(Ft-Fw)/(m1*9.8) %求动力因数f1=0.0076+0.000056*ua %一定车速条件下的滚动阻力 figure(4) plot(ua,D) hold onplot(ua,f1) text(20,0.3,'I') text(20,0.154,'II') text(40,0.1,'III') text(80,0.05,'IV') text(110,0.025,'f') title('汽车动力特性图') xlabel('ua/(km.h)') ylabel('D')1020304050607080900.050.10.150.20.250.30.350.40.45IIIIIIIVf汽车动力特性图ua/(km.h)DIf=0.218Iw1=1.798 Iw2=3.598die1=1+(Iw1+Iw2)/(m1*r^2)+(If*i0^2*nT*ig(1).^2)/(m1*r^2);%一档的旋转质量换算系数die2=1+(Iw1+Iw2)/(m1*r^2)+(If*i0^2*nT*ig(2).^2)/(m1*r^2); die3=1+(Iw1+Iw2)/(m1*r^2)+(If*i0^2*nT*ig(3).^2)/(m1*r^2); die4=1+(Iw1+Iw2)/(m1*r^2)+(If*i0^2*nT*ig(4).^2)/(m1*r^2); die=[die1;die2;die3;die4]';a1=9.8*D(:,1)/die1-9.8*f/die1; %求一档的加速度 a2=9.8*D(:,2)/die2-9.8*f/die2; a3=9.8*D(:,3)/die3-9.8*f/die3; a4=9.8*D(:,4)/die4-9.8*f/die4; aI=1./a1 %求一档的加速度倒数 aII=1./a2 aIII=1./a3 aIV=1./a4aa=[aI,aII,aIII,aIV]';figure(5) %绘制各档的加速度倒数曲线 plot(ua1,aI) hold on plot(ua2,aII) hold onplot(ua3,aIII) hold onplot(ua4,aIV)axis([5 99 0.01 10])10203040506070809012345678910aI aII aIIIaIV加速度倒数曲线ua/(km.h)1/a由图可知,加速度倒数没有交点,则可以在每档达到最大车速时换挡 nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=6.17;If=0.218; Iw1=1.798;Iw2=3.598;L=3.950;a=2.000;hg=0.9;m=3880;g=9.8; G=m*g; ig=[6.09 3.09 1.71 1.00 ]; nmin=600;nmax=4000; u1=0.377*r*nmin./ig/i0; u2=0.377*r*nmax./ig/i0;deta=0*ig; for i=1:4deta(i)=1+(Iw1+Iw2)/(m*r^2)+(If*(ig(i))^2*i0^2*nT)/(m*r^2); endua=[0:0.01:99];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua; Ff=G*f;Fw=CDA*ua.^2/21.15; for i=1:N k=i;if ua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/0.377;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(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i)); delta(i)=0.01*inv_a(i)/3.6; elseif ua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/0.377;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(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i)); delta(i)=0.01*inv_a(i)/3.6;else ua(i)<=u2(4)n=ua(i)*(ig(4)*i0/r)/0.377;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)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i)); delta(i)=0.01*inv_a(i)/3.6; enda=delta(1:k); t(i)=sum(a); endplot(t,ua,'b','LineWidth',2);axis([0 100 0 100]);title('四档汽车二档原地起步换挡加速时间曲线'); xlabel('时间t (s )');ylabel('速度ua (km/h )');1020304050607080901000102030405060708090100四档汽车二档原地起步换挡加速时间曲线时间t (s )速度u a (k m /h )第二大题n=600:1:4000 N=n/1000T=-19.313+295.27*n/1000-165.44*N.*N+40.874*N.*N.*N-3.8445*N.*N.*N .*NPe=T.*n/9550 figure(1) plot(n,T)text(1000,120,'转矩T') hold on plot(n,Pe)text(2000,20,'发动机净功率Pe')5001000150020002500300035004000020406080100120140160180转矩T发动机净功率Pei0=6.17; ig(1)=6.09 ig(2)=3.09 ig(3)=1.71 ig(4)=1.00 nT=0.85 r=0.367 f=0.013 m1=3880 m2=9590 CdA=2.77ua1=0.377*r*n/(ig(1)*i0) ua2=0.377*r*n/(ig(2)*i0) ua3=0.377*r*n/(ig(3)*i0) ua4=0.377*r*n/(ig(4)*i0); ua=10:1:100Pf=m1*9.8*f.*ua/(3600) Pw=CdA*ua.^3/(76140) figure(2) plot(ua1,Pe) hold on plot(ua2,Pe) hold on plot(ua3,Pe) hold onplot(ua4,Pe) hold onplot(ua,(Pf+Pw)/nT)010203040506070809010010203040506070评价:一二三档的后备功率都比较大,可在一定坡度的道路上直接启动加速; 在最高档达到最高车速时,n0=[815 1207 1614 2012 2603 3006 3403 3884]B00=[1326.8 1354.7 1284.4 1122.9 1141.0 1051.2 1233.9 1129.7] B10=[-416.46 -303.98 -189.75 -121.59 -98.893 -73.714 -84.478 -45.291] B20=[72.379 36.657 14.524 7.0035 4.4763 2.8593 2.9788 0.71113]B30=[-5.8629 -2.0533 -0.51184 -0.18517 -0.091077 -0.05138 -0.047449 -0.00075215]B40=[0.17768 0.043072 0.0068164 0.0018555 0.00068906 0.00035032 0.00028230 -0.000038568] B0=spline(n0,B00,n) B1=spline(n0,B10,n) B2=spline(n0,B20,n) B3=spline(n0,B30,n) B4=spline(n0,B40,n)Pf3=m1*9.8*f.*ua3/(3600) Pw3=CdA*ua3.^3/(76140) Pf4=m1*9.8*f.*ua4/(3600) Pw4=CdA*ua4.^3/(76140) Ff1=m1*9.8*ffz3=CdA*ua3.^2/21.15+Ff1 fz4=CdA*ua4.^2/21.15+Ff1 %Pe3=fz3.*ua3./(3600*nT); %Pe4=fz4.*ua4./(3600*nT); Pe3=(Pf3+Pw3)/nTPe4=(Pf4+Pw4)/nTb3=B0+B1.*Pe3+B2.*Pe3.^2+B3.*Pe3.^3+B4.*Pe3.^4 b4=B0+B1.*Pe4+B2.*Pe4.^2+B3.*Pe4.^3+B4.*Pe4.^4Qs4=Pe4.*b4./(1.02*ua4*7.10*9.8) Qs3=Pe3.*b3./(1.02*ua3*7.10*9.8) figure(3)plot(ua4,Qs4) hold on plot(ua3,Qs3)01020304050607080901.41.61.822.22.42.62.8n=600:1:4000 N=n/1000T=-19.313+295.27*n/1000-165.44*N.*N+40.874*N.*N.*N-3.8445*N.*N.*N .*NPe=T.*n/9550 i0=6.17; ig(1)=6.09 ig(2)=3.09 ig(3)=1.71 ig(4)=1.00 nT=0.85 r=0.367 f=0.013 m1=3880 m2=9590 CdA=2.77ua1=0.377*r*n/(ig(1)*i0) ua2=0.377*r*n/(ig(2)*i0) ua3=0.377*r*n/(ig(3)*i0) ua4=0.377*r*n/(ig(4)*i0);n0=[815 1207 1614 2012 2603 3006 3403 3884]B00=[1326.8 1354.7 1284.4 1122.9 1141.0 1051.2 1233.9 1129.7] B10=[-416.46 -303.98 -189.75 -121.59 -98.893 -73.714 -84.478 -45.291]B20=[72.379 36.657 14.524 7.0035 4.4763 2.8593 2.9788 0.71113]B30=[-5.8629 -2.0533 -0.51184 -0.18517 -0.091077 -0.05138 -0.047449 -0.00075215]B40=[0.17768 0.043072 0.0068164 0.0018555 0.00068906 0.00035032 0.00028230 -0.000038568]B0=spline(n0,B00,n)B1=spline(n0,B10,n)B2=spline(n0,B20,n)B3=spline(n0,B30,n)B4=spline(n0,B40,n)Pf3=m1*9.8*f.*ua3/(3600) %三档的滚动阻力功率Pw3=CdA*ua3.^3/(76140) %三档的的空气阻力功率Pf4=m1*9.8*f.*ua4/(3600)Pw4=CdA*ua4.^3/(76140)Ff1=m1*9.8*fPe3=(Pf3+Pw3)/nT %三档的发动机净功率Pe4=(Pf4+Pw4)/nT %四档的发动机净功率b3=B0+B1.*Pe3+B2.*Pe3.^2+B3.*Pe3.^3+B4.*Pe3.^4b4=B0+B1.*Pe4+B2.*Pe4.^2+B3.*Pe4.^3+B4.*Pe4.^4Qs4=Pe4.*b4./(1.02*ua4*7.10) %四档的百公里油耗Qs3=Pe3.*b3./(1.02*ua3*7.10) %三档的百公里油耗ua=[25 40 50]ss=[50 250 250]fz=CdA*ua.^2/21.15+Ff1 %匀速条件下的阻力Pee=fz.*ua/(3600*nT);b=spline(b4,Pe4,Pee) %匀速条件下的燃油消耗率Qsy=Pee.*b./(1.02*ua*7.10)a=[0.2 0.2 -0.36]dt1=1/(3.6*0.2)dt2=1/(3.6*0.2)dt3=1/(3.6*(0.36))ua11=25:1:40ua22=40:1:50ua33=50:-1:25b11=spline(ua4,b4,ua11) %在加速条件下的各个速度节点的燃油消耗率b22=spline(ua4,b4,ua22)b33=spline(ua4,b4,ua33)If=0.218Iw1=1.798Iw2=3.598die4=1+(Iw1+Iw2)/(m1*r^2)+(If*i0^2*nT*ig(4).^2)/(m1*r^2);Pej1=(m1*9.8*f.*ua11/(3600)+CdA.*ua11.^3/(76140)+(die4*m1.*ua11/3600)*0.2)/nT %在三个加速条件下的各个速度节点Pej2=(m1*9.8*f.*ua22/(3600)+CdA.*ua22.^3/(76140)+(die4*m1.*ua22/3 600)*0.2)/nT %的发动机净功率Pej3=(m1*9.8*f.*ua33/(3600)+CdA.*ua33.^3/(76140)+(die4*m1.*ua33/3 600)*0.2)/nT %Qstj1=Pej1.*b11/(367.1*7.10) %在三中加速条件下的,各自的单位时间的燃油消耗量Qstj2=Pej2.*b22/(367.1*7.10)Qstj3=Pej3.*b33/(367.1*7.10)i11=size(Qstj1)i22=size(Qstj2)i33=size(Qstj3)i1=i11(2)i2=i22(2)i3=i33(2)Qt1=Qstj1(2:i1-1)Qt2=Qstj2(2:i2-1)Qt3=Qstj3(2:i3-1)q1=((Qstj1(1)+Qstj1(i1))*dt1./2+sum(Qt1)*dt1)/10q2=((Qstj2(1)+Qstj2(i2))*dt2./2+sum(Qt2)*dt2)/10q3=((Qstj3(1)+Qstj3(i3))*dt3./2+sum(Qt3)*dt3)/10Qall=(q1+q2+q3+Qsy(:,1)+Qsy(:,2)+Qsy(:,3))*100/1075q1 =5.8526q2 =4.9810 q3 =6.0186 Qall =2.7916第三大题(1)m0=4880; %空载质量m/kghg0=0.845; %空载质心高L0=3.95; %空载轴距a0=2.100; %空载质心至前轴距离m=9290; %满载质量m/kghg=1.170; %满载质心高L=3.95; %满载轴距a=2.950; %满载质心至前轴距离BB=0.38; %B为制动力分配系数g=9.8;G=m*g;b=L-a;G0=m0*g;b0=L0-a0;Fu1 =0:1000:100000;Fu2=1/2*(G/hg*(b^2+4*hg*L/G*Fu1).^0.5-(G*b/hg+2*Fu1));Fu02=1/2*(G0/hg0*(b0^2+4*hg0*L0/G0*Fu1).^0.5-(G0*b0/hg0+2*Fu1));F2=(1-B)*Fu1/B;plot(Fu1,Fu2) %绘制满载时的I曲线hold onplot(Fu1,Fu02) %绘制空载时的I曲线hold onplot(Fu1,F2); %%绘制beta曲线title('beta线和I曲线')text(30000,50000,'beta曲线')text(25000,10000,'空载时I曲线')text(25000,30000,'满载时I曲线')xlabel('Fu1')ylabel('Fu2')figure(2)fe=[0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9];for i=1:10Fxb1fk=0:100:120000;Fxb1rk=0:100:120000;Fxb2fk=(L0-fe(i)*hg0)/(fe(i)*hg0).*Fxb1fk-G0*b0/hg0;Fxb2rk=(-1*fe(i)*hg0)/(L0+fe(i)*hg0).*Fxb1rk+fe(i)*G0*a0/(L0+fe(i )*hg0);plot(Fxb1fk,Fxb2fk)hold onplot(Fxb1rk,Fxb2rk,'r')hold onendxlabel('Fxb1')ylabel('Fxb2')axis([0 120000 0 40000])title('空载时的f、r线组图')figure(3)for i=1:10Fxb1fk=0:100:220000;Fxb1rk=0:100:220000;Fxb2fk=(L-fe(i)*hg)/(fe(i)*hg).*Fxb1fk-G*b/hg;Fxb2rk=(-1*fe(i)*hg)/(L+fe(i)*hg).*Fxb1rk+fe(i)*G*a/(L+fe(i)*hg); plot(Fxb1fk,Fxb2fk)hold onplot(Fxb1rk,Fxb2rk,'r')hold onendxlabel('Fxb1')ylabel('Fxb2')axis([0 220000 0 80000])title('满载时的f、r线组图')012345678910x 104-2024681012141618x 104beta 线和I 曲线beta 曲线空载时I 曲线满载时I 曲线Fu1F u 2024681012x 10400.511.522.533.54x 104Fxb1F x b 2空载时的f 、r 线组图00.20.40.60.81 1.21.4 1.6 1.822.2x 105012345678x 104Fxb1F x b 2满载时的f 、r 线组图(2)-(3)m0=4880; %空载质量m/kghg0=0.845; %空载质心高L0=3.95; %空载轴距a0=2.100; %空载质心至前轴距离m=9290; %满载质量m/kghg=1.170; %满载质心高L=3.95; %满载轴距a=2.950; %满载质心至前轴距离BB=0.38; %B 为制动力分配系数g=9.8;G=m*g;b=L-a;G0=m0*g;b0=L0-a0;z=0:0.1:1; %制动强度fef=B*z*L./(b+z*hg);fef0=B*z*L0./(b0+z*hg0);fer=(1-B)*z*L./(a-z*hg);fer0=(1-B)*z*L0./(a0-z*hg0);figure(1)plot(z,fef,z,fef0,z,fer,z,fer0,z,z)text(0.8,1.5,'空车后轮')text(0.8,1.2,'满载后轮')text(0.7,0.6,'满载前轮')text(0.8,0.4,'空车前轮')figure(2)Ef=z./fef*100Ef0=z./fef0*100Er=z./fer*100Er0=z./fer0*100plot(fef,Ef,fer,Er)hold onplot(fef0,Ef0,fer0,Er0)axis([0 1 0 100])text(0.3,90,'Ef')text(0.8,90,'Er 满载')text(0.3,70,'Er 空载')00.10.20.30.40.50.60.70.80.9100.20.40.60.811.21.41.61.82空车后轮满载后轮满载前轮空车前轮00.10.20.30.40.50.60.70.80.910102030405060708090100Ef Er 满载Er 空载m0=4880;hg=0.845;l=3.950;a=2.100;b=1.850;beita=0.38;g=9.8;G0=m0*g ;m=9290;Hg=1.170;L=3.950;A=2.950;B=1.050;beita=0.38;g=9.8;G=m*g;t1=0.02;t2=0.02;ua0=30;fai=0.80;z=0:0.01:1.0;faifk=beita*z*l./(b+z*hg);faifm=beita*z*L./(B+z*Hg);fairk=(1-beita)*z*l./(a-z*hg);fairm=(1-beita)*z*L./(A-z*Hg);Efk=z./faifk*100;Efm=z./faifm*100;Erk=z./fairk*100;Erm=z./fairm*100;ak1=Erk(81)*g*fai/100;am1=Erm(81)*g*fai/100;Sk1=(t1+t2/2)*ua0/3.6+ua0^2/(25.92*ak1);Sm1=(t1+t2/2)*ua0/3.6+ua0^2/(25.92*am1);disp('空载时,汽车制动距离Sk1=');disp(Sk1);disp('满载时,汽车制动距离Sm1=');disp(Sm1);ak2=fai*g*a/(l+fai*hg);am2=fai*g*A/(L+fai*Hg);ak3=fai*g*b/(l-fai*hg);am3=fai*g*B/(L-fai*Hg);Sk2=(t1+t2/2)*ua0/3.6+ua0^2/(25.92*ak2);Sm2=(t1+t2/2)*ua0/3.6+ua0^2/(25.92*am2);Sk3=(t1+t2/2)*ua0/3.6+ua0^2/(25.92*ak3);Sm3=(t1+t2/2)*ua0/3.6+ua0^2/(25.92*am3);disp('空载时,前制动器损坏,汽车制动距离Sk2=');disp(Sk2);disp('满载时,前制动器损坏,汽车制动距离Sm2=');disp(Sm2);disp('空载时,后制动器损坏,汽车制动距离Sk3=');disp(Sk3);disp('满载时,后制动器损坏,汽车制动距离Sm3=');disp(Sm3);空载时,汽车制动距离Sk1=7.8668满载时,汽车制动距离Sm1=5.6354空载时,前制动器损坏,汽车制动距离Sk2=10.0061满载时,前制动器损坏,汽车制动距离Sm2=7.5854空载时,后制动器损坏,汽车制动距离Sk3=8.0879满载时,后制动器损坏,汽车制动距离Sm3=12.9629。

汽车理论课后习题matlab程序

汽车理论课后习题matlab程序

汽车理论课后习题matlab程序1.3.1驱动力阻力平衡图m1=2000;m2=1800;m=3880;r0=0.367;gt=0.85;f=0.013;CDA=2.77;i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;Ig4=[6.09 3.09 1.71 1.00];for i=1:3401;n(i)=i+599;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=1:3401;for j=1:4;Ft(i,j)=Tq(i)*i0*Ig4(j)*gt/r0;ua(i,j)=0.377*r0*n(i)./Ig4(j)/i0;F(i,j)=f*m*9.8+CDA*ua(i,j).^2/21.15; endendplot(ua,Ft,ua,F)xlabel('ua/(km/h)');ylabel('F/N')title('汽车驱动力-行驶阻力平衡图'); gtext('Ft1')gtext('Ft2')gtext('Ft3')gtext('Ft4')gtext('Ff+Fw')grid onaxis(0,120,0,14000)1.3.3加速度倒数曲线m1=2000;m2=1800;m=3880;r0=0.367;gt=0.85;f=0.013;CDA=2.77;i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;Ig4=[6.09 3.09 1.71 1.00];q=1.128;for i=1:3401;n(i)=i+599;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=1:3401;for j=1:4;Ft(i,j)=Tq(i)*i0*Ig4(j)*gt/r0;ua(i,j)=0.377*r0*n(i)./Ig4(j)/i0;F(i,j)=f*m*9.8+CDA*ua(i,j).^2/21.15;b(i,j)=q*m/(Ft(i,j)-0.131*ua(i,j)^2-9.8*m* f);%加速度倒数%endendplot(ua,b);xlabel('ua/(km/h)');ylabel('1/a/(s^2/m)');title('加速度倒数曲线')gtext('1/a1');gtext('1/a2');gtext('1/a3');gtext('1/a4');grid on;axis([0,50,0,5])2.7功率平衡曲线m1=2000;m2=1800;m=3880;r0=0.367;gt=0.85;f=0.013;CDA=2.77;i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;Ig4=[6.09 3.09 1.71 1.00];for i=1:3401;n(i)=i+599;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=1:3401;for j=1:4;Ft(i,j)=Tq(i)*i0*Ig4(j)*gt/r0;ua(i,j)=0.377*r0*n(i)./(Ig4(j)*i0);Pe(i,j)=Ft(i,j)*ua(i,j)/3600;%Pe EXPRESSION%c(i,j)=7.647*ua(i,j)/1000+3.638*ua(i,j)^3/ 100000;%(Pf+Pw)/gt EXPRESSION%end;end;plot(ua,Pe,ua,c);xlabel('ua/(km/h)');ylabel('Pe/kW');title('功率平衡图');gtext('Pe1');gtext('Pe2');gtext('Pe3');gtext('Pe4');gtext('P阻力');grid on;axis([0,90,0,20]);最高档等速百公里油耗曲线i0=5.83;r=0.367;t=0.85;m=3880;G=38024;f=0.013;CdA=2.77;pg=7.12;ig3=1.71;ig4=1;n=[815 1207 1614 2012 2603 3006 3403 3804]; B0=[1326.8 1354.7 1284.4 1122.9 1141.0 1051.2 1233.9 1129.7];B1=[-416.46 -303.98 -189.75 -121.59 -98.893 -73.714 -84.478 -45.291] ;B2=[72.379 36.657 14.524 7.0035 4.4763 2.8593 2.9788 0.71113];B3=[-5.8629 -2.0553 -0.51184 -0.18517 -0.091077 -0.05138 -0.047449 -0.00075215]; B4=[0.17768 0.043072 0.0068164 0.0018555 0.00068906 0.00035032 0.00028230 -0.000038568];ua=(0.377*r*n)/(ig4*i0);Tq=-19.313+295.27*n/1000-165.44*((n/1000).^2)+40.874*((n/1000).^3)-3.8445*((n/1000).^4);P=(1/t)*(G*f*ua/3600+CdA*ua.^3/76140);b=B0+B1.*P+B2.*P.^2+B3.*P.^3+B4.*P.^4;Qs=P.*b./(1.02*ua*pg);b=polyfit(ua,Qs,3);ua4=8:1:100;f=polyval(b,ua4);figure;plot(ua,Qs,'ko',ua4,f,'LineWidth',2);title('汽车最高档等速百公里油耗曲线'); xlabel('ua/(km/h)');ylabel('Qs/[1/L(100km)]');次高档等速百公里油耗曲线i0=5.83;r=0.367;t=0.85;m=3880;G=38024;f=0.013;CdA=2.77;pg=7.12;ig3=1.71;ig4=1;n=[815 1207 1614 2012 2603 3006 3403 3804]; B0=[1326.8 1354.7 1284.4 1122.9 1141.0 1051.2 1233.9 1129.7];B1=[-416.46 -303.98 -189.75 -121.59 -98.893 -73.714 -84.478 -45.291] ;B2=[72.379 36.657 14.524 7.0035 4.4763 2.85932.9788 0.71113];B3=[-5.8629 -2.0553 -0.51184 -0.18517 -0.091077 -0.05138 -0.047449 -0.00075215]; B4=[0.17768 0.043072 0.0068164 0.0018555 0.00068906 0.00035032 0.00028230 -0.000038568];ua=(0.377*r*n)/(ig3*i0);Tq=-19.313+295.27*n/1000-165.44*((n/1000).^2)+40.874*((n/1000).^3)-3.8445*((n/1000).^4);P=(1/t)*(G*f*ua/3600+CdA*ua.^3/76140);b=B0+B1.*P+B2.*P.^2+B3.*P.^3+B4.*P.^4;Qs=P.*b./(1.02*ua*pg);b=polyfit(ua,Qs,3);ua4=8:1:55;f=polyval(b,ua4);figure;plot(ua,Qs,'ko',ua4,f,'LineWidth',2);title('汽车次高档等速百公里油耗曲线'); xlabel('ua/(km/h)');ylabel('Qs/[1/L(100km)]');。

汽车理论习题Matlab程序

汽车理论习题Matlab程序

1.3 确定一轻型货车的动力性能(货车可装用4挡或5挡变速器,任选 其中的一种进行整车性能计算):1)绘制汽车驱动力与行驶阻力平衡图。

2)求汽车最高车速,最大爬坡度及克服该坡度时相应的附着率。

3)绘制汽车行驶加速度倒数曲线,用图解积分法求汽车用2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2档起步加速行驶至70km/h 的加速时间。

轻型货车的有关数据:汽油发动机使用外特性的Tq-n 曲线的拟合公式为23419.313295.27()165.44()40.874() 3.8445()1000100010001000q n n n n T =-+-+-式中,Tq 为发动机转矩(N•m );n 为发动机转速(r/min )。

发动机的最低转速n min =600r/min,最高转速n max =4000r/min 。

装载质量 2000kg 整车整备质量 1800kg 总质量 3880kg 车轮半径 0.367m 传动系机械效率 ηt =0.85 滚动阻力系数 f =0.013 空气阻力系数×迎风面积 C D A =2.77m 2 主减速器传动比 i 0=5.83飞轮转动惯量 I f =0.218kg•m 2 二前轮转动惯量 I w1=1.798kg•m 2 四后轮转动惯量 I w2=3.598kg•m 2质心至前轴距离(满载) a=1.974m 质心高(满载) hg=0.9m解:Matlab 程序:(1) 求汽车驱动力与行驶阻力平衡图和汽车最高车速程序: n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4;m=3880;g=9.8;nmin=600;nmax=4000; G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83; L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598; 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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/i0;ua=[0:5:120];Ff=G*f;Fw=CDA*ua.^2/21.15;Fz=Ff+Fw;plot(ua1,Ft1,ua2,Ft2,ua3,Ft3,ua4,Ft4,ua5,Ft5,ua,Fz);title('驱动力-行驶阻力平衡图');xlabel('ua(km/s)');ylabel('Ft(N)');gtext('Ft1'),gtext('Ft2'),gtext('Ft3'),gtext('Ft4'),gtext('Ft5'),gtext('Ff+Fw'); zoom on;[x,y]=ginput(1);zoom off;disp('汽车最高车速=');disp(x);disp('km/h');汽车最高车速=99.3006km/h(2)求汽车最大爬坡度程序:n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;Ft1=Tq*ig(1)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;Ff=G*f;Fw1=CDA*ua1.^2/21.15;Fz1=Ff+Fw1;Fi1=Ft1-Fz1;Zoom on;imax=100*tan(asin(max(Fi1/G)));disp('汽车最大爬坡度=');disp(imax);disp('%');汽车最大爬坡度=35.2197%(3)求最大爬坡度相应的附着率和求汽车行驶加速度倒数曲线程序:clearn=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/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;Fw5=CDA*ua5.^2/21.15;Ff=G*f;deta1=1+(Iw1+Iw2)/(m*r^2)+(If*ig(1)^2*i0^2*nT)/(m*r^2); deta2=1+(Iw1+Iw2)/(m*r^2)+(If*ig(2)^2*i0^2*nT)/(m*r^2); deta3=1+(Iw1+Iw2)/(m*r^2)+(If*ig(3)^2*i0^2*nT)/(m*r^2); deta4=1+(Iw1+Iw2)/(m*r^2)+(If*ig(4)^2*i0^2*nT)/(m*r^2); deta5=1+(Iw1+Iw2)/(m*r^2)+(If*ig(5)^2*i0^2*nT)/(m*r^2); a1=(Ft1-Ff-Fw1)/(deta1*m);ad1=1./a1;a2=(Ft2-Ff-Fw2)/(deta2*m);ad2=1./a2;a3=(Ft3-Ff-Fw3)/(deta3*m);ad3=1./a3;a4=(Ft4-Ff-Fw4)/(deta4*m);ad4=1./a4;a5=(Ft5-Ff-Fw5)/(deta5*m);ad5=1./a5;plot(ua1,ad1,ua2,ad2,ua3,ad3,ua4,ad4,ua5,ad5);axis([0 99 0 10]);title('汽车的加速度倒数曲线');xlabel('ua(km/h)');ylabel('1/a');gtext('1/a1');gtext('1/a2');gtext('1/a3');gtext('1/a4');gtext('1/a5'); a=max(a1);af=asin(max(Ft1-Ff-Fw1)/G);C=tan(af)/(a/L+hg*tan(af)/L);disp('假设后轮驱动,最大爬坡度相应的附着率=');disp(C);假设后轮驱动,最大爬坡度相应的附着率=0.4219(4) >>clearnT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;L=3.2;a=1.947;hg=0.9;m=3880;g=9.8;G=m*g; ig=[5.56 2.769 1.644 1.00 0.793];nmin=600;nmax=4000;u1=0.377*r*nmin./ig/i0;u2=0.377*r*nmax./ig/i0;deta=0*ig;for i=1:5deta(i)=1+(Iw1+Iw2)/(m*r^2)+(If*(ig(i))^2*i0^2*nT)/(m*r^2);endua=[6:0.01:99];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;Ff=G*f;Fw=CDA*ua.^2/21.15;for i=1:Nk=i;if ua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(4)n=ua(i)*(ig(4)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(4)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elsen=ua(i)*(ig(5)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(5)*i0*nT/r;inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;enda=delta(1:k);t(i)=sum(a);endplot(t,ua);axis([0 80 0 100]);title('汽车2档原地起步换挡加速时间曲线');xlabel('时间t(s)');ylabel('速度ua(km/h)');>> ginputans =25.8223 70.073725.7467 70.0737所以汽车2档原地起步换挡加速行驶至70km/h的加速时间约为25.8s2.7已知货车装用汽油发动机的负荷特性与万有特性。

汽车理论习题Matlab程序

汽车理论习题Matlab程序

1、3确定一轻型货车得动力性能(货车可装用4挡或5挡变速器,任选其中得一种进行整车性能计算):1)绘制汽车驱动力与行驶阻力平衡图。

2)求汽车最高车速,最大爬坡度及克服该坡度时相应得附着率.3)绘制汽车行驶加速度倒数曲线,用图解积分法求汽车用2档起步加速行驶至70km/h得车速—时间曲线,或者用计算机求汽车用2档起步加速行驶至70km/h得加速时间。

轻型货车得有关数据:汽油发动机使用外特性得Tq-n曲线得拟合公式为式中,Tq为发动机转矩(N•m);n为发动机转速(r/min)。

发动机得最低转速n min=600r/min,最高转速n max=4000r/min。

装载质量2000kg整车整备质量1800kg总质量3880kg车轮半径0、367m传动系机械效率ηt=0、85滚动阻力系数f=0、013空气阻力系数×迎风面积C DA=2、77m2主减速器传动比i0=5、83飞轮转动惯量If=0、218kg•m2二前轮转动惯量Iw1=1、798kg•m2四后轮转动惯量I w2=3、598kg•m 2变速器传动比ig(数据如下表)轴距L=3、2m质心至前轴距离(满载)a=1、974m质心高(满载)hg=0、9m解:Matlab程序:(1) 求汽车驱动力与行驶阻力平衡图与汽车最高车速程序:n=[600:10:4000];Tq=-19、313+295、27*(n/1000)-165、44*(n/1000)、^2+40、874*(n/1000)、^3-3、8445*(n/1000)、^4;m=3880;g=9、8;nmin=600;nmax=4000;G=m*g;ig=[5、56 2、769 1、644 1、00 0、793];nT=0、85;r=0、367;f=0、013;CDA=2、77;i0=5、83;L=3、2;a=1、947;hg=0、9;If=0、218;Iw1=1、798;Iw2=3、598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0、377*r*n/ig(1)/i0;ua2=0、377*r*n/ig(2)/i0;ua3=0、377*r*n/ig(3)/i0;ua4=0、377*r*n/ig(4)/i0;ua5=0、377*r*n/ig(5)/i0;ua=[0:5:120];Ff=G*f;Fw=CDA*ua、^2/21、15;Fz=Ff+Fw;plot(ua1,Ft1,ua2,Ft2,ua3,Ft3,ua4,Ft4,ua5,Ft5,ua,Fz);title('驱动力-行驶阻力平衡图');xlabel('ua(km/s)');ylabel('Ft(N)');gtext('Ft1'),gtext(’Ft2'),gtext(’Ft3'),gtext('Ft4'),gtext('Ft5'),gtext(’Ff+Fw’);zoomon;[x,y]=ginput(1);zoom off;disp('汽车最高车速=’);disp(x);disp(’km/h’);汽车最高车速=99、3006km/h(2)求汽车最大爬坡度程序:n=[600:10:4000];Tq=—19、313+295、27*(n/1000)—165、44*(n/1000)、^2+40、874*(n/1000)、^3-3、8445*(n/1000)、^4;m=3880;g=9、8;nmin=600;nmax=4000;G=m*g;ig=[5、562、7691、6441、00 0、793];nT=0、85;r=0、367;f=0、013;CDA=2、77;i0=5、83;L=3、2;a=1、947;hg=0、9;If=0、218;Iw1=1、798;Iw2=3、598;Ft1=Tq*ig(1)*i0*nT/r;ua1=0、377*r*n/ig(1)/i0;Ff=G*f;Fw1=CDA*ua1、^2/21、15;Fz1=Ff+Fw1;Fi1=Ft1—Fz1;Zoomon;imax=100*tan(asin(max(Fi1/G)));disp('汽车最大爬坡度=’);disp(imax);disp(’%’);汽车最大爬坡度=35、2197%(3)求最大爬坡度相应得附着率与求汽车行驶加速度倒数曲线程序:clearn=[600:10:4000];Tq=-19、313+295、27*(n/1000)-165、44*(n/1000)、^2+40、874*(n/1000)、^3-3、8445*(n/1000)、^4;m=3880;g=9、8;nmin=600;nmax=4000;G=m*g;ig=[5、56 2、7691、644 1、00 0、793];nT=0、85;r=0、367;f=0、013;CDA=2、77;i0=5、83;L=3、2;a=1、947;hg=0、9;If=0、218;Iw1=1、798;Iw2=3、598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0、377*r*n/ig(1)/i0;ua2=0、377*r*n/ig(2)/i0;ua3=0、377*r*n/ig(3)/i0;ua4=0、377*r*n/ig(4)/i0;ua5=0、377*r*n/ig(5)/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;Fw5=CDA*ua5、^2/21、15;Ff=G*f;deta1=1+(Iw1+Iw2)/(m*r^2)+(If*ig(1)^2*i0^2*nT)/(m*r^2); deta2=1+(Iw1+Iw2)/(m*r^2)+(If*ig(2)^2*i0^2*nT)/(m*r^2);deta3=1+(Iw1+Iw2)/(m*r^2)+(If*ig(3)^2*i0^2*nT)/(m*r^2); deta4=1+(Iw1+Iw2)/(m*r^2)+(If*ig(4)^2*i0^2*nT)/(m*r^2);deta5=1+(Iw1+Iw2)/(m*r^2)+(If*ig(5)^2*i0^2*nT)/(m*r^2);a1=(Ft1-Ff-Fw1)/(deta1*m);ad1=1、/a1;a2=(Ft2-Ff—Fw2)/(deta2*m);ad2=1、/a2;a3=(Ft3-Ff-Fw3)/(deta3*m);ad3=1、/a3;a4=(Ft4-Ff—Fw4)/(deta4*m);ad4=1、/a4;a5=(Ft5-Ff-Fw5)/(deta5*m);ad5=1、/a5;plot(ua1,ad1,ua2,ad2,ua3,ad3,ua4,ad4,ua5,ad5);axis([099 010]);title('汽车得加速度倒数曲线');xlabel('ua(km/h)’);ylabel('1/a');gtext('1/a1');gtext('1/a2’);gtext(’1/a3');gtext('1/a4');gtext('1/a5');a=max(a1);af=asin(max(Ft1—Ff—Fw1)/G);C=tan(af)/(a/L+hg*tan(af)/L);disp(’假设后轮驱动,最大爬坡度相应得附着率=');disp(C);假设后轮驱动,最大爬坡度相应得附着率=0、4219(4) >>clearnT=0、85;r=0、367;f=0、013;CDA=2、77;i0=5、83;If=0、218;Iw1=1、798;Iw2=3、598;L=3、2;a=1、947;hg=0、9;m=3880;g=9、8;G=m*g;ig=[5、56 2、7691、644 1、00 0、793];nmin=600;nmax=4000;u1=0、377*r*nmin、/ig/i0;u2=0、377*r*nmax、/ig/i0;deta=0*ig;fori=1:5deta(i)=1+(Iw1+Iw2)/(m*r^2)+(If*(ig(i))^2*i0^2*nT)/(m*r^2);endua=[6:0、01:99];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;d elta=0*ua;Ff=G*f;Fw=CDA*ua、^2/21、15;for i=1:Nk=i;ifua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/0、377;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(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff—Fw(i));delta(i)=0、01*inv_a(i)/3、6;elseifua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/0、377;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(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft—Ff-Fw(i));delta(i)=0、01*inv_a(i)/3、6;elseif ua(i)〈=u2(4)n=ua(i)*(ig(4)*i0/r)/0、377;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)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));delta(i)=0、01*inv_a(i)/3、6;elsen=ua(i)*(ig(5)*i0/r)/0、377;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(5)*i0*nT/r;inv_a(i)=(deta(5)*m)/(Ft-Ff—Fw(i));delta(i)=0、01*inv_a(i)/3、6;enda=delta(1:k);t(i)=sum(a);endplot(t,ua);axis([080 0100]);title('汽车2档原地起步换挡加速时间曲线’);xlabel(’时间t(s)’);ylabel(’速度ua(km/h)');>〉ginputans =25、8223 70、073725、746770、0737所以汽车2档原地起步换挡加速行驶至70km/h得加速时间约为25、8s2、7已知货车装用汽油发动机得负荷特性与万有特性。

汽车理论图形MATLAB程序

汽车理论图形MATLAB程序

汽车理论图形MATLAB程序功率平衡图m=1230;g=9.8;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;%绘制汽车驱动力与行驶阻力平衡图for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3); Tq(i)=9549*Pe(i)/n(i);endfor j=1:5for i=1:56Ft(i,j)=Tq(i)*ig(j)*i0*yt/r;ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Fz(i,j)=m*g*f+CD*A*(ua(i,j)^2)/21.15;endendfigureplot(ua,Ft,ua,Fz);title('汽车驱动力与行驶阻力平衡图');xlabel('ua(km/h)');ylabel('Ft(N)');text(20,6700,'Ft1');text(40,4000,'Ft2');text(50,2800,'Ft3');text(80,2000,'Ft4');text(100,1600, 'Ft5');text(100,800,'Ff+Fw');for k=1:56;n=500:100:6000;Pe(k)=Pemax*(n(k)/np+(n(k)/np)^2-(n(k)/np)^3); Tq(k)=9549*Pe(k)/n(k);Ft(k)=T q(k)*ig(4)*i0*yt/r;ua(k)=0.377*r*n(k)/(ig(4)*i0);Fz(k)=m*g*f+CD*A*(ua(k)^2)/21.15;E(k)=abs((Ft(k)-Fz(k)));end[Emin,kmin]=min(E);Umax=ua(kmin)加速度曲线图m=1230;g=9.8;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;deta=[1.33 1.12 1.07 1.05 1.04];for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3); Tq(i)=9549*Pe(i)/n(i);endfor j=1:5for i=1:56Ft(i,j)=Tq(i)*ig(j)*i0*yt/r;ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Fz(i,j)=m*g*f+CD*A*(ua(i,j)^2)/21.15;a(i,j)=(Ft(i,j)-Fz(i,j))/(deta(j)*m);b(i,j)= 1./a(i,j);endendx1=ua(:,1);y1=b(:,1);x2=ua(:,2);y2=b(:,2);x3=ua(:,3);y3=b(:,3);x4=ua(:,4);y4=b(:,4);x5=ua(:,5);y5=b(:,5);figureplot(x1,y1,x2,y2,x3,y3,x4,y4,x5,y5);axis([0 185 0 15]);title('汽车行驶加速度倒数曲线');xlabel('ua(km/h)');ylabel('1/a');汽车二挡原地起步加速时间nT=0.9;r=0.31;f=0.0177;CD=0.31;A=2.2;;i0=3.75;m=3880;g=9.8;Pemax=83;np=6000;G=m*g; ig=[3.615 2.053 1.393 1.031 0.837];nmin=600;nmax=6000;u1=0.377*r*nmin./ig/i0;u2=0.377*r*nmax./ig/i0;deta=[1.33 1.12 1.07 1.05 1.04];ua=[1:0.01:180];N=length(ua);n=0;T q=0;Ft=0;inv_a=0*ua;del ta=0*ua; Ff=G*f;Fw=CD*A*ua.^2/21.15;for i=1:Nk=i;if ua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/0.377;Tq=9549*(Pemax*(n/np+(n/np)^2-(n/np)^3))/n;Ft=Tq*ig(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/0.377;Tq=9549*(Pemax*(n/np+(n/np)^2-(n/np)^3))/n;Ft=Tq*ig(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(4)n=ua(i)*(ig(4)*i0/r)/0.377;Tq=9549*(Pemax*(n/np+(n/np)^2-(n/np)^3))/n;Ft=Tq*ig(4)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elsen=ua(i)*(ig(5)*i0/r)/0.377;Tq=9549*(Pemax*(n/np+(n/np)^2-(n/np)^3))/n;Ft=Tq*ig(5)*i0*nT/r;inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;enda=delta(1:k);t(i)=sum(a);endplot(t,ua);axis([0 80 0 100]);title('汽车2档原地起步换挡加速时间曲线'); xlabel('时间t(s)'); ylabel('速度ua(km/h)');功率平衡图m=1230;g=9.8;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;deta=[1.33 1.12 1.07 1.05 1.04];for j=1:5for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3);Tq(i)=9549*Pe(i)/n(i);ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Pz(i,j)=(m*g*f*ua(i,j)/3600+CD*A*ua(i,j)^3/76140)/yt; endendplot(ua,Pe,ua,Pz);title('功率平衡图');xlabel('ua(km/h)');ylabel('P(kW)');text(40,90,'一档Pe');text(80,90,'二档Pe');text(110,90,'三档Pe');text(150,90,'四档Pe');text(200,90,'五档Pe');text(100,25,'Pz');%绘制最高档和次高档的等速百公里油耗曲线n0=[815,1207,1614,2012,2603,3006,3403,3804];for j=1:5for i=1:8Pd(i)=Pemax*(n0(i)/np+(n0(i)/np)^2-(n0(i)/np)^3); Td(i)=9549*Pd(i)/n0(i);u(i,j)=0.377*r*n0(i)/(ig(j)*i0);endendb(1)=1326.8-416.46*Pd(1)+72.379*Pd(1)^2-5.8629*Pd(1)^3+0.17768*Pd(1)^4;b(2)=1354.7-303.98*Pd(2)+36.657*Pd(2)^2-2.0553*Pd(2)^3+0.043072*Pd(2)^4;b(3)=1284.4-189.75*Pd(3)+14.524*Pd(3)^2-0.51184*Pd(3)^3+0.0068164*Pd(3)^4;b(4)=1122.9-121.59*Pd(4)+7.0035*Pd(4)^2-0.18517*Pd(4)^3+0.0018555*Pd(4)^4;b(5)=1141.0-98.893*Pd(5)+4.4763*Pd(5)^2-0.091077*Pd(5)^3+0.00068906*Pd(5)^4;b(6)=1051.2-73.714*Pd(6)+2.8593*Pd(6)^2-0.05138*Pd(6)^3+0.00035032*Pd(6)^4;b(7)=1233.9-84.478*Pd(7)+2.9788*Pd(7)^2-0.047449*Pd(7)^3+0.00028230*Pd(7)^4;b(8)=1129.7-45.291*Pd(8)+0.71113*Pd(8)^2+0.00075215*Pd(8)^3-0.000038568*Pd(8)^4; u1=u(:,1)';u2=u(:,2)';u3=u(:,3)';u4=u(:,4)';u5=u(:,5)';B1=polyfit(u1,b,3);B2=polyfit(u2,b,3);B3=polyfit(u3,b,3);B4=polyfit(u4,b,3);B5=polyfit(u5,b,3);for k=1:56bh(k,1)=polyval(B1,ua(k,1));bh(k,2)=polyval(B2,ua(k,2));bh(k,3)=polyval(B3,ua(k,3));bh(k,4)=polyval(B4,ua(k,4));bh(k,5)=polyval(B5,ua(k,5));endfor i=1:5for k=1:56Q(k,i)=Pz(k,i)*bh(k,i)/(1.02*ua(k,i)*7.10);endendplot(ua(:,4),Q(:,4),ua(:,5),Q(:,5));axis([0 185 0 20]);title('最高档(五档)和次高档(四档)等速百公里油耗图'); xlabel('ua(km/h)');ylabel('Qs(L/100km)');text(90,10,'四档');text(125,10,'五档');爬坡度图m=1230;g=9.8;G=m*g;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3);Tq(i)=9549*Pe(i)/n(i);endfor j=1:5for i=1:56Ft(i,j)=Tq(i)*ig(j)*i0*yt/r;ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Fz(i,j)=m*g*f+CD*A*(ua(i,j)^2)/21.15;F=Ft-Fz;I=tan(asin(Ft/G))*100;endendplot(ua,I);hold on;title('汽车的爬坡度图');xlabel('ua(km/h)');ylabel('i(%)');text(50,55,'一档');text(50,35,'二档');text(100,22,'三档');text(150,15,'四档');text(200,13,'五档');动力因数图m=1230;g=9.8;G=m*g;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;%绘制汽车驱动力与行驶阻力平衡图for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3); Tq(i)=9549*Pe(i)/n(i);endfor j=1:5for i=1:56Ft(i,j)=Tq(i)*ig(j)*i0*yt/r;ua(i,j)=0.377*r*n(i)/(ig(j)*i0); Fw(i,j)=CD*A*(ua(i,j)^2)/21.15; F=Ft-Fw;D=F/G;endendplot(ua,D);hold on;axis([0 190 0 0.6]);title('汽车的动力特性图'); xlabel('ua(km/h)');ylabel('动力因数)');text(40,0.5,'一档');text(60,0.3,'二档');text(100,0.2,'三档');text(140,0.1,'四档');text(140,0.04,'五档');。

[交通运输]汽车理论课后习题Matlab程序

[交通运输]汽车理论课后习题Matlab程序

1.3 确定一轻型货车的动力性能(货车可装用4挡或5挡变速器,任选 其中的一种进行整车性能计算):1)绘制汽车驱动力与行驶阻力平衡图。

2)求汽车最高车速,最大爬坡度及克服该坡度时相应的附着率。

3)绘制汽车行驶加速度倒数曲线,用图解积分法求汽车用2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2档起步加速行驶至70km/h 的加速时间。

轻型货车的有关数据:汽油发动机使用外特性的Tq-n 曲线的拟合公式为23419.313295.27()165.44()40.874() 3.8445()1000100010001000q n n n n T =-+-+- 式中,Tq 为发动机转矩(N •m );n 为发动机转速(r/min )。

发动机的最低转速n min =600r/min,最高转速n max =4000r/min 。

装载质量 2000kg整车整备质量 1800kg总质量 3880kg车轮半径 0.367m传动系机械效率 ηt =0.85滚动阻力系数 f =0.013空气阻力系数×迎风面积 C D A =2.77m 2主减速器传动比 i 0=5.83飞轮转动惯量 I f =0.218kg•m 2二前轮转动惯量 I w1=1.798kg•m 2四后轮转动惯量 I w2=3.598kg•m 2质心至前轴距离(满载) a=1.974m质心高(满载) hg=0.9m解:Matlab 程序:(1) 求汽车驱动力与行驶阻力平衡图和汽车最高车速程序:n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83; L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/i0;ua=[0:5:120];Ff=G*f;Fw=CDA*ua.^2/21.15;Fz=Ff+Fw;plot(ua1,Ft1,ua2,Ft2,ua3,Ft3,ua4,Ft4,ua5,Ft5,ua,Fz);title('驱动力-行驶阻力平衡图');xlabel('ua(km/s)');ylabel('Ft(N)');gtext('Ft1'),gtext('Ft2'),gtext('Ft3'),gtext('Ft4'),gtext('Ft5'),gtext('Ff+Fw'); zoom on;[x,y]=ginput(1);zoom off;disp('汽车最高车速=');disp(x);disp('km/h');汽车最高车速=99.3006km/h(2)求汽车最大爬坡度程序:n=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;Ft1=Tq*ig(1)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;Ff=G*f;Fw1=CDA*ua1.^2/21.15;Fz1=Ff+Fw1;Fi1=Ft1-Fz1;Zoom on;imax=100*tan(asin(max(Fi1/G)));disp('汽车最大爬坡度=');disp(imax);disp('%');汽车最大爬坡度=35.2197%(3)求最大爬坡度相应的附着率和求汽车行驶加速度倒数曲线程序:clearn=[600:10:4000];Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/10 00).^4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;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;Ft5=Tq*ig(5)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/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;Fw5=CDA*ua5.^2/21.15;Ff=G*f;deta1=1+(Iw1+Iw2)/(m*r^2)+(If*ig(1)^2*i0^2*nT)/(m*r^2); deta2=1+(Iw1+Iw2)/(m*r^2)+(If*ig(2)^2*i0^2*nT)/(m*r^2); deta3=1+(Iw1+Iw2)/(m*r^2)+(If*ig(3)^2*i0^2*nT)/(m*r^2); deta4=1+(Iw1+Iw2)/(m*r^2)+(If*ig(4)^2*i0^2*nT)/(m*r^2); deta5=1+(Iw1+Iw2)/(m*r^2)+(If*ig(5)^2*i0^2*nT)/(m*r^2); a1=(Ft1-Ff-Fw1)/(deta1*m);ad1=1./a1;a2=(Ft2-Ff-Fw2)/(deta2*m);ad2=1./a2;a3=(Ft3-Ff-Fw3)/(deta3*m);ad3=1./a3;a4=(Ft4-Ff-Fw4)/(deta4*m);ad4=1./a4;a5=(Ft5-Ff-Fw5)/(deta5*m);ad5=1./a5;plot(ua1,ad1,ua2,ad2,ua3,ad3,ua4,ad4,ua5,ad5);axis([0 99 0 10]);title('汽车的加速度倒数曲线');xlabel('ua(km/h)');ylabel('1/a');gtext('1/a1');gtext('1/a2');gtext('1/a3');gtext('1/a4');gtext('1/a5'); a=max(a1);af=asin(max(Ft1-Ff-Fw1)/G);C=tan(af)/(a/L+hg*tan(af)/L);disp('假设后轮驱动,最大爬坡度相应的附着率=');disp(C);假设后轮驱动,最大爬坡度相应的附着率=0.4219(4) >>clearnT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;L=3.2;a=1.947;hg=0.9;m=3880;g=9.8;G=m*g; ig=[5.56 2.769 1.644 1.00 0.793];nmin=600;nmax=4000;u1=0.377*r*nmin./ig/i0;u2=0.377*r*nmax./ig/i0;deta=0*ig;for i=1:5deta(i)=1+(Iw1+Iw2)/(m*r^2)+(If*(ig(i))^2*i0^2*nT)/(m*r^2);endua=[6:0.01:99];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;Ff=G*f;Fw=CDA*ua.^2/21.15;for i=1:Nk=i;if ua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(4)n=ua(i)*(ig(4)*i0/r)/0.377;Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/100 0)^4;Ft=Tq*ig(4)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elsen=ua(i)*(ig(5)*i0/r)/0.377;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(5)*i0*nT/r;inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;enda=delta(1:k);t(i)=sum(a);endplot(t,ua);axis([0 80 0 100]);title('汽车2档原地起步换挡加速时间曲线');xlabel('时间t (s )');ylabel('速度ua (km/h )');>> ginputans =25.8223 70.073725.7467 70.0737所以汽车2档原地起步换挡加速行驶至70km/h 的加速时间约为25.8s2.7已知货车装用汽油发动机的负荷特性与万有特性。

汽车理论图表-matlab编程

汽车理论图表-matlab编程

附:matlab程序及图像第一题驱动力与阻力平衡图n=600:1:5000;u=0:0.1:120;m=3695;g=9.8;r=0.37;nT=0.87;f=0.012;Ff=m*g*f;CdA=2.60;Fw=CdA*u.^2/21.15;i0=5.83;ig1=6.12;ig2=3.11;ig3=1.69;ig4=1.00;Tq=-19.31+296*(n/1000)-165*(n/1000).^ 2+40.9*(n/1000).^3-3.85*(n/1000).^4; ua1=0.377*r*n/(ig1*i0);Ft1=Tq*ig1*i0*nT/r;plot(ua1,Ft1,'k');hold on;ua2=0.377*r*n/(ig2*i0);Ft2=Tq*ig2*i0*nT/r;plot(ua2,Ft2,'k');ua3=0.377*r*n/(ig3*i0);Ft3=Tq*ig3*i0*nT/r;plot(ua3,Ft3,'k');ua4=0.377*r*n/(ig4*i0);Ft4=Tq*ig4*i0*nT/r;plot(ua4,Ft4,'k');plot(u,Ff+Fw,'k');grid on;xlabel('车速(km/h)');ylabel('F(n)');title('驱动力与阻力平衡图');加速度倒数曲线图n=600:1:4000;m=3695;f=0.012;g=9.8;CdA=2.60;nT=0.87;Iw1=1.8;Iw2=3.6;If=0.22;i0=5.83;ig1=6.12;ig2=3.11;ig3=1.69;ig4=1.00;r=0.37;Ff=m*g*f;Tq=-19.31+296*(n/1000)-165*(n/1000).^2+40.9*(n/1000).^3-3.85*(n/1000).^4; ua1=0.377*r*n/(ig1*i0);Ft1=Tq*ig1*i0*nT/r;Fw1=CdA*ua1.^2/21.15;deta1=1+(Iw1*2+Iw2*4)/(m*r^2)+If*ig1^2*i0^2*nT/(m*r^2); a1=(Ft1-Ff-Fw1)/deta1*m;ua2=0.377*r*n/(ig2*i0);Ft2=Tq*ig2*i0*nT/r;Fw2=CdA*ua2.^2/21.15;deta2=1+(Iw1*2+Iw2*4)/(m*r^2)+If*ig2^2*i0^2*nT/(m*r^2); a2=(Ft2-Ff-Fw2)/deta2*m;ua3=0.377*r*n/(ig3*i0);Ft3=Tq*ig3*i0*nT/r;Fw3=CdA*ua3.^2/21.15;deta3=1+(Iw1*2+Iw2*4)/(m*r^2)+If*ig3^2*i0^2*nT/(m*r^2); a3=(Ft3-Ff-Fw3)/deta3*m;ua4=0.377*r*n/(ig4*i0);Ft4=Tq*ig4*i0*nT/r;Fw4=CdA*ua4.^2/21.15;deta4=1+(Iw1*2+Iw2*4)/(m*r^2)+If*ig4^2*i0^2*nT/(m*r^2); a4=(Ft4-Ff-Fw4)/deta4*m;plot(ua1,1./a1,'k','linewidth',1);hold on;plot(ua2,1./a2,'k','linewidth',1);plot(ua3,1./a3,'k','linewidth',1);plot(ua4,1./a4,'k','linewidth',1);grid on;xlabel('车速(km/h)');ylabel('1/a');title('加速度倒数曲线');汽车动力因数特性曲线图n=600:1:4000;m=3695;f=0.012;g=9.8;CdA=2.60;nT=0.87;Iw1=1.8;Iw2=3.6;If=0.22;i0=5.83;ig1=6.12;ig2=3.11;ig3=1.69;ig4=1.00;r=0.37;Ff=m*g*f;Tq=-19.31+296*(n/1000)-165*(n/1000).^2+40.9*(n/1000).^3-3.85*(n/1000).^4; ua1=0.377*r*n/(ig1*i0);Ft1=Tq*ig1*i0*nT/r;Fw1=CdA*ua1.^2/21.15;deta1=1+(Iw1*2+Iw2*4)/(m*r^2)+If*ig1^2*i0^2*nT/(m*r^2);a1=(Ft1-Ff-Fw1)/deta1*m;ua2=0.377*r*n/(ig2*i0);Ft2=Tq*ig2*i0*nT/r;Fw2=CdA*ua2.^2/21.15;deta2=1+(Iw1*2+Iw2*4)/(m*r^2)+If*ig2^2*i0^2*nT/(m*r^2);a2=(Ft2-Ff-Fw2)/deta2*m;ua3=0.377*r*n/(ig3*i0);Ft3=Tq*ig3*i0*nT/r;Fw3=CdA*ua3.^2/21.15;deta3=1+(Iw1*2+Iw2*4)/(m*r^2)+If*ig3^2*i0^2*nT/(m*r^2);a3=(Ft3-Ff-Fw3)/deta3*m;ua4=0.377*r*n/(ig4*i0);Ft4=Tq*ig4*i0*nT/r;Fw4=CdA*ua4.^2/21.15;deta4=1+(Iw1*2+Iw2*4)/(m*r^2)+If*ig4^2*i0^2*nT/(m*r^2); a4=(Ft4-Ff-Fw4)/deta4*m;D1=f+deta1.*a1/g;D2=f+deta2.*a2/g;D3=f+deta3.*a3/g;D4=f+deta4.*a4/g;plot(ua1,D1,'k');hold on;plot(ua2,D2,'k');plot(ua3,D3,'k');plot(ua4,D4,'k');grid on;xlabel('车速(km/h)');ylabel('D');title('汽车动力因数特性曲线');第二题汽车功率平衡图n=600:1:4000;ua=0:0.1:120;m=3695;f=0.012;g=9.8;CdA=2.60;Iw1=1.8;Iw2=3.6;If=0.22;i0=5.83;ig1=6.12;ig2=3.11;ig3=1.69;ig4=1.00;r=0.37;Ff=m*g*f;Tq=-19.31+296*(n/1000)-165*(n/1000).^2+40.9*(n/1000).^3-3.85*(n/1000).^4; ua1=0.377*r*n/(ig1*i0);Pe1=Tq.*ua1*(ig1*i0/(3600*r));ua1=0.377*r*n/(ig1*i0);plot(ua1,Pe1,'k');hold on;ua2=0.377*r*n/(ig2*i0);Pe2=Tq.*ua2*(ig2*i0/(3600*r));ua2=0.377*r*n/(ig2*i0);plot(ua2,Pe2,'k');ua3=0.377*r*n/(ig3*i0);Pe3=Tq.*ua3*(ig3*i0/(3600*r));ua3=0.377*r*n/(ig3*i0);plot(ua3,Pe3,'k');ua4=0.377*r*n/(ig4*i0);Pe4=Tq.*ua4*(ig4*i0/(3600*r));ua4=0.377*r*n/(ig4*i0);plot(ua4,Pe4,'k');Pf=1/0.87*(m*g*f*ua/3600+2.60*ua.^3/76140);plot(ua,Pf,'k');xlabel('ua(km/h)'); ylabel('P(kw)');title('汽车功率平衡图');。

汽车理论matlab验证编程及图

汽车理论matlab验证编程及图
程序:
ig=[6.09,3.09,1.71,1]; for i=1:4 n=600:1:4000; t=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^33.8445*(n/1000).^4; ft=t*ig(i)*5.83*0.85/0.367; ua=0.377*0.367*n/ig(i)/5.83; ff=3880*9.8*0.013+2.77/21.15*ua.*ua; mh=3880+5.4/0.367/0.367+0.218*5.83*5.83*ig(i)^2*0.85/0.367/0.367; a=(ft-ff)/mh; m=1./a; str=['r','m','b','c']; plot(ua,m,str(i)); grid on; hold on; end xlabel('速度(Km/h)'),ylabel('加速度倒数(s^2/m)') title('汽车行驶加速度倒数曲线') legend('一档加速度倒数','二档加速度倒数','三档加速度倒数','四档加速度 倒数',2)
legend('一档发动机功率','二档发动机功率','三档发动机功率','四档发 动机功率','汽车行驶阻力功率',2)
画驱动力与行驶阻力平衡图的MATLAB源程序:
ig=[6.09,3.09,1.71,1]; for i=1:4 n=600:4000; t=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4; ua=0.377*0.367*n./ig(i)/5.83; u=ua.*1000/3600; pe=t.*ig(i)*5.83.*u./0.367; str=['r','m','b','c'];

汽车理论课后作业matlab编程详细讲解(带注释)

汽车理论课后作业matlab编程详细讲解(带注释)

1.3matlab程序:(1)%驱动力-行驶阻力平衡图%货车相关参数。

m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;ig=[5.56 2.769 1.644 1.00 0.793];y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;n=600:10:4000;%发动机转数转换成汽车行驶速度。

ua1=0.377*r*n/ig(1)/i0;ua2=0.377*r*n/ig(2)/i0;ua3=0.377*r*n/ig(3)/i0;ua4=0.377*r*n/ig(4)/i0;ua5=0.377*r*n/ig(5)/i0;%计算各档位驱动力。

Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4 ;Ft1=Tq*ig(1)*i0*y/r;Ft2=Tq*ig(2)*i0*y/r;Ft3=Tq*ig(3)*i0*y/r;Ft4=Tq*ig(4)*i0*y/r;Ft5=Tq*ig(5)*i0*y/r;%计算行驶阻力。

Fz1=m*g*f+2.77*ua1.^2/21.15;Fz2=m*g*f+2.77*ua2.^2/21.15;Fz3=m*g*f+2.77*ua3.^2/21.15;Fz4=m*g*f+2.77*ua4.^2/21.15;Fz5=m*g*f+2.77*ua5.^2/21.15;%驱动力-行驶阻力平衡图。

plot(ua1,Ft1,ua2,Ft2,ua3,Ft3,ua4,Ft4,ua5,Ft5,ua1,Fz1,'k',ua2,Fz2,'k',ua3,Fz3,'k',ua 4,Fz4,'k',ua5,Fz5,'k');title('驱动力-行驶阻力平衡图');xlabel('ua(km/s)');ylabel('Ft(N)');legend('Ft1','Ft2','Ft3','Ft4','Ft5','Ff+Fw')%求最高车速。

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功率平衡图m=1230;g=9.8;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;%绘制汽车驱动力与行驶阻力平衡图for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3);Tq(i)=9549*Pe(i)/n(i);endfor j=1:5for i=1:56Ft(i,j)=Tq(i)*ig(j)*i0*yt/r;ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Fz(i,j)=m*g*f+CD*A*(ua(i,j)^2)/21.15;endendfigureplot(ua,Ft,ua,Fz);title('汽车驱动力与行驶阻力平衡图');xlabel('ua(km/h)');ylabel('Ft(N)');text(20,6700,'Ft1');text(40,4000,'Ft2');text(50,2800,'Ft3');text(80,2000,'Ft4');text(100,1600, 'Ft5');text(100,800,'Ff+Fw');for k=1:56;n=500:100:6000;Pe(k)=Pemax*(n(k)/np+(n(k)/np)^2-(n(k)/np)^3);Tq(k)=9549*Pe(k)/n(k);Ft(k)=Tq(k)*ig(4)*i0*yt/r;ua(k)=0.377*r*n(k)/(ig(4)*i0);Fz(k)=m*g*f+CD*A*(ua(k)^2)/21.15;E(k)=abs((Ft(k)-Fz(k)));end[Emin,kmin]=min(E);Umax=ua(kmin)加速度曲线图m=1230;g=9.8;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;deta=[1.33 1.12 1.07 1.05 1.04];for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3);Tq(i)=9549*Pe(i)/n(i);endfor j=1:5for i=1:56Ft(i,j)=Tq(i)*ig(j)*i0*yt/r;ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Fz(i,j)=m*g*f+CD*A*(ua(i,j)^2)/21.15;a(i,j)=(Ft(i,j)-Fz(i,j))/(deta(j)*m);b(i,j)= 1./a(i,j);endendx1=ua(:,1);y1=b(:,1);x2=ua(:,2);y2=b(:,2);x3=ua(:,3);y3=b(:,3);x4=ua(:,4);y4=b(:,4);x5=ua(:,5);y5=b(:,5);figureplot(x1,y1,x2,y2,x3,y3,x4,y4,x5,y5);axis([0 185 0 15]);title('汽车行驶加速度倒数曲线');xlabel('ua(km/h)');ylabel('1/a');汽车二挡原地起步加速时间nT=0.9;r=0.31;f=0.0177;CD=0.31;A=2.2;;i0=3.75;m=3880;g=9.8;Pemax=83;np=6000;G=m*g; ig=[3.615 2.053 1.393 1.031 0.837];nmin=600;nmax=6000;u1=0.377*r*nmin./ig/i0;u2=0.377*r*nmax./ig/i0;deta=[1.33 1.12 1.07 1.05 1.04];ua=[1:0.01:180];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua; Ff=G*f;Fw=CD*A*ua.^2/21.15;for i=1:Nk=i;if ua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/0.377;Tq=9549*(Pemax*(n/np+(n/np)^2-(n/np)^3))/n;Ft=Tq*ig(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/0.377;Tq=9549*(Pemax*(n/np+(n/np)^2-(n/np)^3))/n;Ft=Tq*ig(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elseif ua(i)<=u2(4)n=ua(i)*(ig(4)*i0/r)/0.377;Tq=9549*(Pemax*(n/np+(n/np)^2-(n/np)^3))/n;Ft=Tq*ig(4)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;elsen=ua(i)*(ig(5)*i0/r)/0.377;Tq=9549*(Pemax*(n/np+(n/np)^2-(n/np)^3))/n;Ft=Tq*ig(5)*i0*nT/r;inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));delta(i)=0.01*inv_a(i)/3.6;enda=delta(1:k);t(i)=sum(a);endplot(t,ua);axis([0 80 0 100]);title('汽车2档原地起步换挡加速时间曲线'); xlabel('时间t(s)');ylabel('速度ua(km/h)');功率平衡图m=1230;g=9.8;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;deta=[1.33 1.12 1.07 1.05 1.04];for j=1:5for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3);Tq(i)=9549*Pe(i)/n(i);ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Pz(i,j)=(m*g*f*ua(i,j)/3600+CD*A*ua(i,j)^3/76140)/yt;endendplot(ua,Pe,ua,Pz);title('功率平衡图');xlabel('ua(km/h)');ylabel('P(kW)');text(40,90,'一档Pe');text(80,90,'二档Pe');text(110,90,'三档Pe');text(150,90,'四档Pe');text(200,90,'五档Pe');text(100,25,'Pz');%绘制最高档和次高档的等速百公里油耗曲线n0=[815,1207,1614,2012,2603,3006,3403,3804];for j=1:5for i=1:8Pd(i)=Pemax*(n0(i)/np+(n0(i)/np)^2-(n0(i)/np)^3);Td(i)=9549*Pd(i)/n0(i);u(i,j)=0.377*r*n0(i)/(ig(j)*i0);endendb(1)=1326.8-416.46*Pd(1)+72.379*Pd(1)^2-5.8629*Pd(1)^3+0.17768*Pd(1)^4;b(2)=1354.7-303.98*Pd(2)+36.657*Pd(2)^2-2.0553*Pd(2)^3+0.043072*Pd(2)^4;b(3)=1284.4-189.75*Pd(3)+14.524*Pd(3)^2-0.51184*Pd(3)^3+0.0068164*Pd(3)^4;b(4)=1122.9-121.59*Pd(4)+7.0035*Pd(4)^2-0.18517*Pd(4)^3+0.0018555*Pd(4)^4;b(5)=1141.0-98.893*Pd(5)+4.4763*Pd(5)^2-0.091077*Pd(5)^3+0.00068906*Pd(5)^4;b(6)=1051.2-73.714*Pd(6)+2.8593*Pd(6)^2-0.05138*Pd(6)^3+0.00035032*Pd(6)^4;b(7)=1233.9-84.478*Pd(7)+2.9788*Pd(7)^2-0.047449*Pd(7)^3+0.00028230*Pd(7)^4;b(8)=1129.7-45.291*Pd(8)+0.71113*Pd(8)^2+0.00075215*Pd(8)^3-0.000038568*Pd(8)^4; u1=u(:,1)';u2=u(:,2)';u3=u(:,3)';u4=u(:,4)';u5=u(:,5)';B1=polyfit(u1,b,3);B2=polyfit(u2,b,3);B3=polyfit(u3,b,3);B4=polyfit(u4,b,3);B5=polyfit(u5,b,3);for k=1:56bh(k,1)=polyval(B1,ua(k,1));bh(k,2)=polyval(B2,ua(k,2));bh(k,3)=polyval(B3,ua(k,3));bh(k,4)=polyval(B4,ua(k,4));bh(k,5)=polyval(B5,ua(k,5));endfor i=1:5for k=1:56Q(k,i)=Pz(k,i)*bh(k,i)/(1.02*ua(k,i)*7.10);endendplot(ua(:,4),Q(:,4),ua(:,5),Q(:,5));axis([0 185 0 20]);title('最高档(五档)和次高档(四档)等速百公里油耗图'); xlabel('ua(km/h)');ylabel('Qs(L/100km)');text(90,10,'四档');text(125,10,'五档');爬坡度图m=1230;g=9.8;G=m*g;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3);Tq(i)=9549*Pe(i)/n(i);endfor j=1:5for i=1:56Ft(i,j)=Tq(i)*ig(j)*i0*yt/r;ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Fz(i,j)=m*g*f+CD*A*(ua(i,j)^2)/21.15;F=Ft-Fz;I=tan(asin(Ft/G))*100;endendplot(ua,I);hold on;title('汽车的爬坡度图');xlabel('ua(km/h)');ylabel('i(%)');text(50,55,'一档');text(50,35,'二档');text(100,22,'三档');text(150,15,'四档');text(200,13,'五档');动力因数图m=1230;g=9.8;G=m*g;ig=[3.615 2.053 1.393 1.031 0.837]; i0=3.75;r=0.31;yt=0.9;f=0.017;CD=0.31;A=2.2;np=6000;Pemax=83;%绘制汽车驱动力与行驶阻力平衡图for i=1:56;n=500:100:6000;Pe(i)=Pemax*(n(i)/np+(n(i)/np)^2-(n(i)/np)^3);Tq(i)=9549*Pe(i)/n(i);endfor j=1:5for i=1:56Ft(i,j)=Tq(i)*ig(j)*i0*yt/r;ua(i,j)=0.377*r*n(i)/(ig(j)*i0);Fw(i,j)=CD*A*(ua(i,j)^2)/21.15;F=Ft-Fw;D=F/G;endendplot(ua,D);hold on;axis([0 190 0 0.6]);title('汽车的动力特性图');xlabel('ua(km/h)');ylabel('动力因数)');text(40,0.5,'一档');text(60,0.3,'二档');text(100,0.2,'三档');text(140,0.1,'四档');text(140,0.04,'五档');。

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