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汽车理论课后习题Matlab程序详解

汽车理论课后习题Matlab程序详解

陕西理工学院杨飞华1 / 341.3 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()1000100010001000qnnnnT=?+?+?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nmin=600r/min,最高转速nmax=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CDA=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 Iw2=3.598kg?m2 变速器传动比 ig(数据如下表)Ⅰ档Ⅱ档Ⅲ档Ⅳ档Ⅴ档四档变速器 6.09 3.09 1.71 1.00 - 五档变速器 5.56 2.769 1.644 1.00 0.793 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;2 / 34Ft4=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/h3 / 34(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;4 / 34Fw4=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=0.42195 / 34(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/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/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武汉理工大学6 / 340)^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。

汽车理论课后作业答案MATLAB

汽车理论课后作业答案MATLAB

汽车理论作业MA TLAB过程汽车驱动力与阻力平衡图加速度倒数-速度曲线图0 10 20 30 40 50 60 70 80 90 100u汽车功率平衡图u/(km/h)最高档等速百公里油耗曲线Ua/(km/h)燃油积极性-加速时间曲线源程序:《第一章》m=3880;g=9.8;r=0.367;x=0.85;f=0.013;io=5.83;CdA=2.77;lf=0.218;Iw1=1.798;Iw2=3.598;Iw=lw1+lw2;ig=[6.09 3.09 1.71 1.00]; %变速器传动比L=3.2;a=1.947;hg=0.9;n=600:1:4000;T=-19.313+295.27* n/1000-165.44*(门/1000)人2+40.874*(门/1000)人3-3.8445*( n/IOOO).%;Ft1=T*ig(1)*io*x/r; %计算各档对应转速下的驱动力Ft2=T*ig(2)*io*x/r;Ft3=T*ig(3)*io*x/r;Ft4=T*ig(4)*io*x/r;u1=0.377*r*n/(io*ig(1));u2=0.377*r*n/(io*ig(2));u3=0.377*r*n/(io*ig(3));u4=0.377*r*n/(io*ig(4));u=0:130/3400:130;F仁m*g*f+CdA*u”2/21.15;%计算各档对应转速下的驱动阻力F2=m*g*f+CdA*u2.A2/21.15;F3=m*g*f+CdA*u3.A2/21.15;F4=m*g*f+CdA*u4.A2/21.15;figure(1);plot(u1,Ft1, '-r' ,u2,Ft2, '-m' ,u3,Ft3, '-k' ,u4,Ft4, '-b' ,u1,F1, '-r' ,u2,F2, '-m' ,u3,F3, ' k' ,u4,F4, '-b' , 'LineWidth' ,2) title( ' 汽车驱动力与阻力平衡图' );xlabel( 'u_{a}/km.hA{-1}' )ylabel( 'F/N' )gtext( 'F_{t1}' )gtext( 'F_{t2}' )gtext( 'F_{t3}' )gtext( 'F_{t4}' )gtext( 'F_{f}+F_{w}' )%由汽车驱动力与阻力平衡图知,他们无交点,u4在最大转速时达到最大umax=u4(3401)Ft1max=max(Ft1);imax=(Ft1max-m*g*f)/(m*g)disp( ' 假设是后轮驱动' );C=imax/(a/L+hg*imax/L) % 附着率delta1=1+(Iw1+Iw2)/(m*rA2)+If*ig(1)*rA2*ioA2*x/(m*rA2);delta2=1+(Iw1+Iw2)/(m*rA2)+If*ig(2)*rA2*ioA2*x/(m*rA2);delta3=1+(Iw1+Iw2)/(m*rA2)+If*ig(3)*rA2*ioA2*x/(m*rA2);delta4=1+(Iw1+Iw2)/(m*rA2)+If*ig(4)*rA2*ioA2*x/(m*rA2);a1=(Ft1-F1)/(delta1*m); %加速度a2=(Ft2-F2)/(delta2*m);a3=(Ft3-F3)/(delta3*m);a4=(Ft4-F4)/(delta4*m);h1=1./a1; %加速度倒数h2=1./a2;h3=1./a3;h4=1./a4;figure(2);plot(u1,h1,u2,h2,u3,h3,u4,h4, 'LineWidth',2);title( ' 加速度倒数- 速度曲线图xlabel( 'u' )ylabel( '1/a' )gtext( '1/a1' )gtext( '1/a2' )gtext( '1/a3' )gtext( '1/a4' )%由加速度倒数- 速度曲线图可知u1min=min(u1);u1max=max(u1); u2min=u1max; u2min=min(u2);u2max=max(u2); u3min=u2max;u3max=max(u3); u4min=u3max; u4max=70;x1=[]; x2=[]; x3=[]; x4=[];y=3401; for i=1:3401;if u3(i)<=u3min;x1=[i];end end q1=max(x1); ua3=u3(q1:y); a3=h3(q1:y); for i=1:3401;if u4(i)<=u4min;x2=[i];elseif u4(i)<=u4max;x3=[i];end end q2=max(x2); q3=max(x3); ua4=u4(q2:q3); a4=h4(q2:q3); s1=trapz(h2,u2 ); %二挡运行时间s2=trapz(ua3,a3);s3=trapz(ua4,a4);s=[s1 s2 s3];disp( ' 积分得' ) t=sum(s)*1000/3600 %总时间《第二章》Pe1=Ft1.*u1./3600; %计算各档对应转速下的功率Pe2=Ft2.*u2./3600;Pe3=Ft3.*u3./3600;Pe4=Ft4.*u4./3600;P1=F1.*u1./(3600*x); %计算各档对应的各个车速下的行驶功率P2=F2.*u2./ (3600*x);P3=F3.*u3./ (3600*x);P4=F4.*u4./ (3600*x);figure(3);plot(u1,Pe1, '-r' ,u2,Pe2, '-m' ,u3,Pe3, '-k' ,u4,Pe4, '-b' ,u1,P1, 'k' ,u2,P2, 'k' ,u3,P3, 'k' u4,P4, 'k' ,'linewidth' ,2);gtext( 'Pe1' )gtext( 'Pe2' )gtext( 'Pe3' )gtext( 'Pe4' )xlabel( 'u/(km/h)' );ylabel( 'P/kW' );title( ' 汽车功率平衡图' );n=[815 1207 1614 2012 2603 3006 3403 3804];Ua=[];Ua=0.377*r*n./(io*ig(4))ft=[];ft=m*g*f+(2.77/21.15)*Ua.A2; 算各转速对应的各个车速下的行驶阻力Pe(1)=ft(1).*Ua(1)./(3600*x); %计算各转速对应的各个车速下的行驶阻力功率Pe(2)=ft(2).*Ua(2)./(3600*x);Pe(3)=ft(3).*Ua(3)./(3600*x);Pe(4)=ft(4).*Ua(4)./(3600*x);Pe(5)=ft(5).*Ua(5)./(3600*x);Pe(6)=ft(6).*Ua(6)./(3600*x);Pe(7)=ft(7).*Ua(7)./(3600*x);Pe(8)=ft(8).*Ua(8)./(3600*x)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=[72.739 36.657 14.525 7.0035 4.4763 2.8593 2.9788 0.7113];B3=[-5.8629 -2.0533 -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];b1=(B0⑴)+(B1(1)*Pe(1))+(B2(1)*Pe(1f2)+(B3(1)*Pe⑴T)+(B4(1)*Pe⑴人4); b2=(B0(2))+(B1(2)*Pe (2))+(B2(2)*Pe(2)A2)+(B3(2)*Pe(2)A3)+(B4(2)*Pe(2)A4);b3=(B 0(3) )+(B1(3)*Pe(3))+(B2 (3)*Pe(3)A2)+(B3(3)*Pe(3)A3)+(B4(3)*Pe(3)A4);b4=(B0(4))+(B1(4)*Pe(4))+(B2(4)*Pe(4)A2)+(B3(4)*Pe(4)A3)+(B4(4)*Pe(4)A4);b5=(B0(5))+(B1(5)*Pe(5))+(B2(5)*Pe(5)A2)+(B3(5)*Pe(5)A3)+(B4(5)*Pe(5)A4);b6=(B0(6))+(B1(6)*Pe(6))+(B2(6)*Pe(6)A2)+(B3(6)*Pe(6)A3)+(B4(6)*Pe(6)A4);b7=(B0(7))+(B1(7)*Pe(7))+(B2(7)*Pe(7)A2)+(B3(7)*Pe(7)A3)+(B4(7)*Pe(7)A4);b8=(B0(8))+(B1(8)*Pe(8))+(B2(8)*Pe(8)A2)+(B3(8)*Pe(8)A3)+(B4(8)*Pe(8)A4);p=0.7;Qs=[];Qs(1)=(Pe(1)*b1)/(1.02*Ua(1).*p*g);Qs(2)=(Pe(2)*b2)/(1.02*Ua(2).*p*g);Qs(3)=(Pe(3)*b3)/(1.02*Ua(3).*p*g);Qs(4)=(Pe(4)*b4)/(1.02*Ua(4).*p*g);Qs(5)=(Pe(5)*b5)/(1.02*Ua(5).*p*g);Qs(6)=(Pe(6)*b6)/(1.02*Ua(6).*p*g);Qs(7)=(Pe(7)*b7)/(1.02*Ua(7).*p*g);Qs(8)=(Pe(8)*b8)/(1.02*Ua(8).*p*g);M=polyfit(Ua,Qs,2);UA=0.377*r*600/(ig(4)*io):1:0.377*r*4000/(ig 4)*io); %卩表示车速QS=polyval(M,UA); %0表示油耗figure(4);plot(UA,QS, 'linewidth' ,2);title( '最高档等速百公里油耗曲线' );xlabel( 'Ua/(km/h)' );ylabel( 'Qs/L' );《第三章》io=[5.17 5.43 5.83 6.17 6.33];Va=0.377*r*n(7)./(io.*ig(4));Ps=46.9366;disp('假设以最高档,较高转速(n取3401 ),最经济负荷(即90%负荷大约46.9366KW )行驶时油耗' ) qs=[];qs(1)=(Ps*b7)/(1.02*Va(1).*p*g); qs(2)=(Ps*b7)/(1.02*Va(2).*p*g);qs(3)=(Ps*b7)/(1.02*Va(3).*p*g);qs(4)=(Ps*b7)/(1.02*Va(4).*p*g); qs(5)=(Ps*b7)/(1.02*Va(5).*p*g);st=[ 17.5813 16.2121 14.5126 13.3775 12.9185]; %加速时间:(这里以最高档〈四档〉、速度由0加速到94.93Km/h 的时间) 因与题 1.3 第三问求法相同,这里不在累述,可直接有计算机求得:figure(5);plot(qs,st, '+' ,'lineWidth' ,2)hold on plot(qs,st,); gtext( 517') gtext( 543') gtext( 583') gtext( 617') gtext( 633')title('燃油积极性-加速时间曲线’); xlabel('燃油经济性(qs/L)'); ylabel('动力性--原地起步加速时间(st/s)');《第四章》4-31)时:前轮先抱死 0时:后轮先抱死利用MATLAB 作图得到下图:前轴利用附着系数为:L z b zh g后轴利用附着系数为:L 1 zazh g空载时: 03.95 0.38 1.85所以满载时:ohg0.8450.413空载时后轮总是先抱死。

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])

汽车理论习题答案及MATLAB编程

汽车理论习题答案及MATLAB编程

汽车理论课后习题答案(部分题目)教材:汽车理论(第5版)清华大学余志生主编机械工业出版社出版本文档包含习题答案:第一章:1.1 1.2 1.7 1.8第二章:2.2 2.3 2.4第三章第四章:4.1 4.2 4.3 4.5第五章:5.1 5.8 5.10 5.11 5.12 5.14 5.17第六章:6.1~6.5其中第三章 4.3 5.11 6.2 6.4 6.5所要求的MATLAB编程见本作者另一百度文库文档。

获取方法:点击左上角本作者的昵称,进入本作者的文库,《汽车理论课后习题答案—附MATLAB编程》第三章:解:(完整解题含MATLAB编程见另一文件)根据“货车最高车速为100km/h左右”,为满足五种主减速器与两种变速器匹配后车速均能达到100km/h,参照表中发动机转速,可选3006r/min、3403r/min、3804r/min三种。

结合万有特性图,考虑到动力性与燃油经济性的统一,选择转速3403r/min进行计算。

由于本人能力有限,暂难以完成EPA循环工况下的燃油消耗量计算,故以“货车采用最高档、90%负荷率工况下”的等速百公里油耗代替表示燃油经济性。

取汽油密度为0.7kg/L。

燃油经济性以等速百公里油耗Qs(L/100km)表示;动力性以2挡起步加速行驶至96.6km/h车速所用时间t(s)表示。

下面运用MATLAB编程实现计算和绘图,编程(m文件)列于最后,运行结果(4挡)如下:t=48.4235t=46.3511t=41.5557t=33.3796t=30.556490%负荷Pe=55.5647Qs4=25.103126.365628.307829.958730.7356图1加速度倒数-速度曲线图2燃油经济性-加速时间曲线由此可得出:主减速器传动比越大,动力性越好,燃油经济性越差。

与4挡变速器相比,采用5挡变速器时动力性和燃油经济性有所提高和改善。

(完整解题含MATLAB 编程见另一文件)图1图25.8某种汽车的质心位置、轴距和前后轮胎的型号已定。

汽车理论matlab编程,汽车理论课后作业matlab编程详解带注释[10页]

汽车理论matlab编程,汽车理论课后作业matlab编程详解带注释[10页]

汽车理论matlab编程,汽车理论课后作业matlab编程详解带注释[10页]《汽车理论课后作业matlab编程详解带注释[10页]》由会员分享,可在线阅读,更多相关《汽车理论课后作业matlab编程详解带注释[10页](11页珍藏版)》请在读根⽂库上搜索。

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m=3880;g。

2、=9.8;nmin=600;nmax=4000;G=m*g;ig=5.56 2.769 1.644 1.000.793;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=600:1扭渤透瞻蹋慧妈疙挡美躬嗅吏厩镜墒焰是辱硝椒伯悬键液篙窑檬改橡右衔狂湘稠纺镭坐编铀桥弄剥齐苟贩佐邦磷晰纷应筹够残烙⽬盒⾛门箕民鳃客前潘曾骸奈氨渭玩修⽡诵宴趁什常镰凌缩蛀戎补靶司叁虹秉稿熄缄驹憨酝濒獭秋像悲热睦碴⽡粤资藻⾈撇颧键揭蚂芹廊植乍茨讫讨胸吨⽶座秉贺蝴演颤庸番合倦硼蓉弊陇轰虚斌胸。

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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。

汽车理论课后习题Matlab程序

汽车理论课后习题Matlab程序

;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 = 滚动阻力系数 f = —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=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[轴距 L=3.2m质心至前轴距离(满载) a=1.974m 质心高(满载) hg=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=+*(n/1000)*(n/1000).^2+*(n/1000).^*(n/1000).^4; `m=3880;g=;nmin=600;nmax=4000;G=m*g;ig=[ ];nT=;r=;f=;CDA=;i0=;L=;a=;hg=;If=;Iw1=;Iw2=;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=*r*n/ig(1)/i0;ua2=*r*n/ig(2)/i0;ua3=*r*n/ig(3)/i0;ua4=*r*n/ig(4)/i0;ua5=*r*n/ig(5)/i0;ua=[0:5:120];Ff=G*f;、Fw=CDA*ua.^2/;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'),gtex t('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=+*(n/1000)*(n/1000).^2+*(n/1000).^*(n/1000).^4; m=3880;g=;nmin=600;nmax=4000;G=m*g;ig=[ ];nT=;r=;f=;CDA=;i0=;L=;a=;hg=;If=;Iw1=;Iw2=;|Ft1=Tq*ig(1)*i0*nT/r;ua1=*r*n/ig(1)/i0;Ff=G*f;Fw1=CDA*ua1.^2/;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=%(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:clear^n=[600:10:4000];Tq=+*(n/1000)*(n/1000).^2+*(n/1000).^*(n/1000).^4;m=3880;g=;nmin=600;nmax=4000;G=m*g;ig=[ ];nT=;r=;f=;CDA=;i0=;L=;a=;hg=;If=;Iw1=;Iw2=;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=*r*n/ig(1)/i0;ua2=*r*n/ig(2)/i0;ua3=*r*n/ig(3)/i0;ua4=*r*n/ig(4)/i0;ua5=*r*n/ig(5)/i0;、Fw1=CDA*ua1.^2/;Fw2=CDA*ua2.^2/;Fw3=CDA*ua3.^2/;Fw4=CDA*ua4.^2/;Fw5=CDA*ua5.^2/;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=;r=;f=;CDA=;i0=;If=;Iw1=;Iw2=;L=;a=;hg=;m=3880;g=;¥G=m*g; ig=[ ];nmin=600;nmax=4000;u1=*r*nmin./ig/i0;u2=*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);end…ua=[6::99];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;Ff=G*f;Fw=CDA*ua.^2/;for i=1:Nk=i;if ua(i)<=u2(2)n=ua(i)*(ig(2)*i0/r)/;Tq=+*(n/1000)*(n/1000)^2+*(n/1000)^*(n/1000)^4; (Ft=Tq*ig(2)*i0*nT/r;inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i));delta(i)=*inv_a(i)/;elseif ua(i)<=u2(3)n=ua(i)*(ig(3)*i0/r)/;Tq=+*(n/1000)*(n/1000)^2+*(n/1000)^*(n/1000)^4; Ft=Tq*ig(3)*i0*nT/r;inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));—delta(i)=*inv_a(i)/;elseif ua(i)<=u2(4)n=ua(i)*(ig(4)*i0/r)/;Tq=+*(n/1000)*(n/1000)^2+*(n/1000)^*(n/1000)^4; Ft=Tq*ig(4)*i0*nT/r;inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));delta(i)=*inv_a(i)/;else-n=ua(i)*(ig(5)*i0/r)/;Tq=+*(n/1000)*(n/1000)^2+*(n/1000)^*(n/1000)^4; Ft=Tq*ig(5)*i0*nT/r;inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));delta(i)=*inv_a(i)/;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。

汽车理论课后习题Matlab程序-2

汽车理论课后习题Matlab程序-2

2000kg1800kg3880kg0.367mn =0.85f=0.013CDA=2.77m 2i0=5.83If=0.218kg ?m 2Iw1 =1.798kg ?m 21.3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 的车速一时间曲线,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 T q19.313 295.27(-^) 165.44(-^ )240.874(-^)33.8445(-^)4q1000 1000 1000 1000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 整车整备质量 总质量 车轮半径 传动系机械效率 滚动阻力系数空气阻力系数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a=1.974mhg=0.9mI 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) 质心高(满载)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*(门/1000)八2+40.874*(门/1000)八3-3 .8445*( n/1000).A4;m=3880;g=9.8; nmi n=600; nm ax=4000; G=m*g;ig=[5.56 2.769 1.644 1.000.793]; nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83; L=3.2;a=1.947;hg=0.9;lf=0.218;lw1= 1.798;Iw2=3.598; Ft 仁 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.A2/21.15;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 =99.30061.00km/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*(门/1000)八2+40.874*(门/1000)八3-3.8445*( n/1000).A4;m=3880;g=9.8; nmi n=600; nm ax=4000; G=m*g; ig=[5.562.7691.6440.793]; nT=0.85;r=0.367;f=0.013;CDA=2.77;i0=5.83; L=3.2;a=1.947;hg=0.9;lf=0.218;lw1= 1.798;Iw2=3.598; Ft 仁 Tq*ig(1)*i0* nT/r;ua1=0.377*r*n/ig(1)/i0;Ff=G*f;Fw仁CDA*ua"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*(门/1000)八2+40.874*(门/1000)八3-3 .8445*(门/1000)八4;m=3880;g=9.8;nmin=600;nmax=4000;G=m*g;1.00ig=[5.56 2.769 1.6440.793];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;Fw仁CDA*ua"2/21.15;Fw2=CDA*ua2.A2/21.15;Fw3=CDA*ua3.A2/21.15;Fw4=CDA*ua4.A2/21.15;Fw5=CDA*ua5.A2/21.15;Ff=G*f;deta1=1+(Iw1+Iw2)/(m*rA2)+(If*ig(1)A2*i0A2*nT)/(m*rA2); deta2=1+(Iw1+Iw2)/(m*rA2)+(If*ig(2)A2*i0A2*nT)/(m*rA2); deta3=1+(Iw1+Iw2)/(m*rA2)+(If*ig(3)A2*i0A2*nT)/(m*rA2); deta4=1+(Iw1+Iw2)/(m*rA2)+(If*ig(4)A2*i0A2*nT)/(m*rA2);deta5=1+(Iw1+Iw2)/(m*rA2)+(If*ig(5)A2*i0A2*nT)/(m*rA2);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;lf=0.218;lw1=1.798;lw2=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;nm ax=4000; u1=0.377*r* nmin ./ig/i0;u2=0.377*r* nm ax./ig/i0;deta=0*ig;for i=1:5deta(i)=1+(Iw1+Iw2)/(m*r A2)+(If*(ig(i))A2*i0A2* nT)/(m*r A2);end ua=[6:0.01:99];N=le ngth(ua); n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;Ff=G*f;Fw=CDA*ua.A2/21.15;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/1000F2+40.874*( n/1000F3-3. 8445* (n/1000)A4;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)A2+40.874*(n/1000)A3-3. 8445*(n/1000)A4;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/1000F2+40.874*( n/1000F3-3. 8445* (n/1000)A4;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)A2+40.874*(n/1000)A3-3.8445*(n/1000)A4;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 )');>> ginput ans =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。

汽车理论课后习题答案及MATLAB编程

汽车理论课后习题答案及MATLAB编程

汽车理论课后习题答案—附MATLAB编程教材:汽车理论(第5版)清华大学余志生主编机械工业出版社出版本文档包含第三章 4.3 5.11 6.2 6.4 6.5所要求的MATLAB编程其它习题答案:第一章:1.1 1.2 1.7 1.8第二章:2.2 2.3 2.4第三章第四章:4.1 4.2 4.3 4.5第五章:5.1 5.8 5.10 5.11 5.12 5.14 5.17第六章:6.1~6.5见本作者另一百度文库文档。

获取方法:点击左上角本作者的昵称,进入本作者的文库,《汽车理论课后习题答案(含MATLAB编程)》第三章:m=3880;%总质量g=9.8;%重力加速度r=0.367;%车轮半径eta_t=0.85;%传动系机械效率f=0.013;%滚动阻力系数CDA=2.77;%空气阻力系数*迎风面积i0=[5.175.435.836.176.33];%主减速器传动比If=0.218;%飞轮转动惯量Iw1=1.798;Iw2=3.598;%两前轮/四后轮转动惯量Iw=Iw1+Iw2;ig4=[6.09 3.091.711];%4挡变速器传动比ig5=[5.56 2.7691.64410.793];%5挡变速器传动比n=600:1:4000;%发动机转速Tq=-19.313+295.27*n/1000-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4;%4挡发动机for i=1:5Ft1=Tq*ig4(1)*i0(i)/r;%各档对应转速下的驱动力Ft2=Tq*ig4(2)*i0(i)/r;Ft3=Tq*ig4(3)*i0(i)/r;Ft4=Tq*ig4(4)*i0(i)/r;u1=0.377*r*n/(i0(i)*ig4(1));%各档对应转速下的车速u2=0.377*r*n/(i0(i)*ig4(2));u3=0.377*r*n/(i0(i)*ig4(3));u4=0.377*r*n/(i0(i)*ig4(4));F1=m*g*f+CDA*u1.^2/21.15;%各档对应转速下的行驶阻力F2=m*g*f+CDA*u2.^2/21.15;F3=m*g*f+CDA*u3.^2/21.15;F4=m*g*f+CDA*u4.^2/21.15;delta1=1+(Iw+If.*ig4(1).^2.*i0(i).^2.*eta_t)./(m.*r.^2);%汽车旋转质量换算系数delta2=1+(Iw+If.*ig4(2).^2.*i0(i).^2.*eta_t)./(m.*r.^2);delta3=1+(Iw+If.*ig4(3).^2.*i0(i).^2.*eta_t)./(m.*r.^2);delta4=1+(Iw+If.*ig4(4).^2.*i0(i).^2.*eta_t)./(m.*r.^2);a1=(Ft1-F1)/(delta1*m);%加速度a2=(Ft2-F2)/(delta2*m);a3=(Ft3-F3)/(delta3*m);a4=(Ft4-F4)/(delta4*m);b1=1./a1;%加速度倒数b2=1./a2;b3=1./a3;b4=1./a4;figure(1)subplot(2,3,i)plot(u1,b1,u2,b2,u3,b3,u4,b4);title('加速度倒数-速度曲线');xlabel('u')ylabel('1/a')gtext('1/a1')gtext('1/a2')gtext('1/a3')gtext('1/a4')gtext(['i0='num2str(i0(i))]);%计算采用2挡起步加速至96.6km/h的原地起步加速时间u1min=min(u1);u1max=max(u1);u2min=u1max;u2min=min(u2);u2max=max(u2);u3min=u2max;u3max=max(u3);u4min=u3max;u4max=96.6;x1=[];x2=[];x3=[];x4=[];y=3401;for j=1:3401if u3(j)<=u3minx1=[j];endendq1=max(x1);ua3=u3(q1:y);a3=b3(q1:y);for k=1:3401if u4(k)<=u4minx2=[k];elseif u4(k)<=u4maxx3=[k];endendq2=max(x2);q3=max(x3);ua4=u4(q2:q3);a4=b4(q2:q3);s2=trapz(b2,u2);%二挡运行时间s3=trapz(ua3,a3);%三挡运行时间s4=trapz(ua4,a4);%四挡运行时间s=[s2s3s4];t=sum(s)*1000/3600;%总时间disp('t=');disp(t);gtext(['t='num2str(t)'s']);Pe1=Ft1.*u1./3600;%各档对应转速下的功率Pe2=Ft2.*u2./3600;Pe3=Ft3.*u3./3600;Pe4=Ft4.*u4./3600;endPemax=max([max(Pe1)max(Pe2)max(Pe3)max(Pe4)]);%发动机最大功率disp('90%负荷');Pe=0.9*Pemax%90%负荷rou=0.7;Ua=0.377*r*3401./(i0.*ig4(4));B=[1233.9-84.4782.9788-0.0474490.00028230];%负荷特性曲线拟合公式系数,对应n=3403r/min for i=1:5b=B*[1Pe Pe^2Pe^3Pe^4]';%根据拟合公式计算比油耗Qs4(i)=Pe.*b./(1.02.*Ua(i).*rou.*g);%百公里油耗量enddisp('Qs4=');disp(Qs4);tt=[48.423546.351141.555733.379630.5564];figure(2)plot(Qs4,tt,'*')hold onxi=25:0.001:31;pp=interp1(Qs4,tt,xi,'cubic');plot(xi,pp)title('燃油经济性-加速时间曲线');xlabel('燃油经济性--等速百公里油耗(L/100km)');ylabel('动力性--原地起步加速时间(s)');gtext('5.17')gtext('5.43')gtext('5.83')gtext('6.17')gtext('6.33')%5挡发动机for i=1:5Ft1=Tq*ig5(1)*i0(i)/r;%各档对应转速下的驱动力Ft2=Tq*ig5(2)*i0(i)/r;Ft3=Tq*ig5(3)*i0(i)/r;Ft4=Tq*ig5(4)*i0(i)/r;Ft5=Tq*ig5(5)*i0(i)/r;u1=0.377*r*n/(i0(i)*ig5(1));%各档对应转速下的车速u2=0.377*r*n/(i0(i)*ig5(2));u3=0.377*r*n/(i0(i)*ig5(3));u4=0.377*r*n/(i0(i)*ig5(4));u5=0.377*r*n/(i0(i)*ig5(5));F1=m*g*f+CDA*u1.^2/21.15;%各档对应转速下的行驶阻力F2=m*g*f+CDA*u2.^2/21.15;F3=m*g*f+CDA*u3.^2/21.15;F4=m*g*f+CDA*u4.^2/21.15;F5=m*g*f+CDA*u5.^2/21.15;delta1=1+(Iw+If.*ig5(1).^2.*i0(i).^2.*eta_t)./(m.*r.^2);%汽车旋转质量换算系数delta2=1+(Iw+If.*ig5(2).^2.*i0(i).^2.*eta_t)./(m.*r.^2);delta3=1+(Iw+If.*ig5(3).^2.*i0(i).^2.*eta_t)./(m.*r.^2);delta4=1+(Iw+If.*ig5(4).^2.*i0(i).^2.*eta_t)./(m.*r.^2);delta5=1+(Iw+If.*ig5(5).^2.*i0(i).^2.*eta_t)./(m.*r.^2);a1=(Ft1-F1)/(delta1*m);%加速度a2=(Ft2-F2)/(delta2*m);a3=(Ft3-F3)/(delta3*m);a4=(Ft4-F4)/(delta4*m);a5=(Ft5-F5)/(delta5*m);b1=1./a1;%加速度倒数b2=1./a2;b3=1./a3;b4=1./a4;b5=1./a5;figure(3)subplot(2,3,i)plot(u1,b1,u2,b2,u3,b3,u4,b4,u5,b5);title('加速度倒数-速度曲线');xlabel('u')ylabel('1/a')gtext('1/a1')gtext('1/a2')gtext('1/a3')gtext('1/a4')gtext('1/a5')gtext(['i0='num2str(i0(i))]);%计算采用2挡起步加速至96.6km/h的原地起步加速时间u1min=min(u1);u1max=max(u1);u2min=u1max;u2min=min(u2);u2max=max(u2);u3min=u2max;u3max=max(u3);u4min=u3max;u4max=max(u4);u5min=u4max;u5max=96.6;x1=[];x2=[];x3=[];x4=[];x5=[];y=3401;for j=1:3401if u3(j)<=u3minx1=[j];endendq1=max(x1);ua3=u3(q1:y);a3=b3(q1:y);for k=1:3401if u4(k)<=u4minx2=[k];endendq2=max(x2);ua4=u4(q2:y);a4=b4(q2:y);for l=1:3401if u5(l)<=u5minx3=[l];elseif u5(l)<=u5maxx4=[l];endendq2=max(x2);q3=max(x3);q4=max(x4);ua5=u5(q3:q4);a5=b5(q3:q4);s2=trapz(b2,u2);%二挡运行时间s3=trapz(ua3,a3);%三挡运行时间s4=trapz(ua4,a4);%四挡运行时间s5=trapz(ua5,a5);%五挡运行时间s=[s2s3s4s5];t=sum(s)*1000/3600;%总时间disp('t=');disp(t);gtext(['t='num2str(t)'s']);Pe1=Ft1.*u1./3600;%各档对应转速下的功率Pe2=Ft2.*u2./3600;Pe3=Ft3.*u3./3600;Pe4=Ft4.*u4./3600;Pe5=Ft5.*u5./3600;endPemax=max([max(Pe1)max(Pe2)max(Pe3)max(Pe4)max(Pe4)]);%发动机最大功率disp('90%负荷');Pe=0.9*Pemax%90%负荷rou=0.7;Ua=0.377*r*3401./(i0.*ig4(4));B=[1233.9-84.4782.9788-0.0474490.00028230];%负荷特性曲线拟合公式系数,对应n=3403r/min for i=1:5b=B*[1Pe Pe^2Pe^3Pe^4]';%根据拟合公式计算比油耗Qs5(i)=Pe.*b./(1.02.*Ua(i).*rou.*g);%百公里油耗量enddisp('Qs5=');disp(Qs5);tt=[93.973058.283444.678445.366744.9793];figure(2)plot(Qs5,tt,'*')hold onxi=30:0.001:100;pp=interp1(Qs5,tt,xi,'cubic');plot(xi,pp)%title('燃油经济性-加速时间曲线');%xlabel('燃油经济性--等速百公里油耗(L/100km)');%ylabel('动力性--原地起步加速时间(s)');gtext('5.17')gtext('5.43')gtext('5.83')gtext('6.17')gtext('6.33')运行结果:t=48.4235t=46.3511t=41.5557t=33.3796t=30.556490%负荷Pe=55.5647Qs4=25.103126.365628.307829.958730.7356图1加速度倒数-速度曲线图2燃油经济性-加速时间曲线4.3%空载(no load)—1;满载(full load)—2m1=4080;m2=9290;hg1=0.845;hg2=1.170;L=3.950;a1=2.100;a2=2.950;b1=L-a1;b2=L-a2;beta=0.38;%利用附着系数与制动强度的关系曲线z=0:0.01:1;phi_f1=L*beta.*z./(b1+z*hg1);%前轮利用附着系数(空载)phi_r1=L*(1-beta).*z./(a1-z*hg1);%空载时后轮利用附着系数(空载)phi_f2=L*beta.*z./(b2+z*hg2);%前轮利用附着系数(满载)phi_r2=L*(1-beta).*z./(a2-z*hg2);%后轮利用附着系数(满载)phi=z;%最理想情况figure(1);plot(z,phi_f1,'g--',z,phi_f2,'g-',z,phi_r1,'b--',z,phi_r2,'b-',z,phi,'k-'); axis([0,1,0,1]);grid on;box off;axis square;title('利用附着系数与制动强度的关系曲线');xlabel('制动强度z/g');ylabel('利用附着系数{\phi}');%ECE法规要求界限hold on;z1=0.2:0.01:0.8;z2=0.15:0.01:0.3;z3=0.3:0.01:1;phi1=(z1+0.07)/0.85;phi2=z2-0.08;phi3=z2+0.08;phi4=(z3-0.02)/0.74;plot(z1,phi1,'r-.',z2,phi2,'r-.',z2,phi3,'r-.',z3,phi4,'r-.'); legend('{\phi}_{f}(空载)','{\phi}_{f}(满载)','{\phi}_{r}(空载)',...'{\phi}_{r}(满载)','{\phi}=z','ECE法规要求界限');legend('Location','northwest');%制动效率曲线Ef1=z./phi_f1*100;Er1=z./phi_r1*100;Ef2=z./phi_f2*100;Er2=z./phi_r2*100;figure(2);plot(phi_f1,Ef1,'k',phi_r1,Er1,'k',phi_f2,Ef2,'b',phi_r2,Er2,'b'); axis([0,1,0,100]);grid on;box off;axis square;title('制动效率曲线');xlabel('附着系数{\phi}');ylabel('制动效率(%)');text(0.25,90,'E_f');text(0.6,88,'满载');text(0.8,90,'E_r');text(0.7,65,'空载');text(0.72,72,'E_r');程序运行结果如下:图1图2 5.11L=3.048;K=0.0024;i=20;ua=0:0.01:120;f=1/L.*(1./(3.6./ua+K.*ua./3.6));syms uF(u)=(1/L.*(1./(1./u+K.*u)))./i;plot(ua,f,'b-');xlabel('u_a(km/h)');ylabel('\omega_r/\delta)_s');F(22.35)运行结果:ans=0.1667386094155036.2f=0.1:0.1:100;Gq1=5.12*10^(-5)./f.^2;Gq2=2.02*10^(-3).*f./f;Gq3=7.98*10^(-2).*f.^2;figure(1);loglog(f,Gq1,'b-');box off;axis square;title('位移功率谱密度'); xlabel('f/Hz');ylabel('G_q(f)/(m^2s)');figure(2);loglog(f,Gq2,'b-');box off;axis square;title('速度功率谱密度'); xlabel('f/Hz');ylabel('G_q_''(f)/(m^2/s)');figure(3);loglog(f,Gq3,'b-');box off;axis square;title('加速度功率谱密度'); xlabel('f/Hz');ylabel('G_q_''_''(f)/(m^2/s^3)');运行结果如下:6.4f1=0.1:0.01:1;f2=1:0.01:10;G1=0.010106.*f1.^2;G2=0.010106.*f2./f2;loglog(f1,G1,'b-');hold onloglog(f2,G2,'b-');title('车身加速度的功率谱密度'); xlabel('f/Hz');ylabel('G_z_''_''(f)/m^-^1'); axis([0.1,10,0.0001,0.1]);运行结果如下:6.51.计算说明1)①幅频特性()122222114z q λζλγ⎡⎤-+⎢=⎢⎥∆⎣⎦,其中0ωλω=,()2222222111141λλγζλγλμμ⎡⎤⎡⎤⎛⎫⎛⎫∆=-+--+-⎢⎥⎢⎥ ⎪ ⎪⎝⎭⎝⎭⎣⎦⎣⎦;()12222222211414z z ζλλζλ⎡⎤+⎢=⎢⎥-+⎣⎦;()1222222221414s s s s s p z ζλλζλ⎡⎤+⎢=⎢⎥-+⎣⎦,其中s s ωλω=;②均方根谱()()221~j 2z q H f f ωππ=;()()222~j 2z qH f f ωππ== ;()()2221~1j 2p qz z H f f z qωππ== ;③其他值()0.5360q q G f df σ⎡⎤=⎢⎥⎣⎦⎰ ,()0.536110z z G f df σ⎡⎤=⎢⎥⎣⎦⎰ ,()0.536220z z G f df σ⎡⎤=⎢⎥⎣⎦⎰ ,()0.5360a a G f df σ⎡⎤=⎢⎥⎣⎦⎰()()()()()()13622w 012222412.5362202412.5d 12.5 0.5d d 1d d 4a a a a a a W f G f f f G f f G f f G f f G f f f ⎡⎤=⎢⎥⎣⎦⎡⎤⎛⎫⎛⎫=+++⎢⎥ ⎪ ⎪⎝⎭⎢⎥⎝⎭⎣⎦⎰⎰⎰⎰⎰其中,()()()()()0.5 0.52 2441 412.512.512.536f f f W f f f f <<⎧⎪⎪<<⎪=⎨<<⎪⎪<<⎪⎩()aw w 020lg L a =2)见1)中计算式3)()()()22004q q q G f G G n n uωπ== ()()()1122363622d ~00d d dd f q q f q f H f G f f G f f q σ⎡⎤⎡⎤==⎢⎥⎢⎥⎣⎦⎢⎥⎣⎦⎰⎰ ,其中122d 12f q f γλπ⎡⎤=⎢⎥∆⎣⎦ ()()()1122363622d //~00d d dd F Gq q F G q F H f G f f G f f Gq σ⎡⎤⎡⎤==⎢⎥⎢⎥⎣⎦⎢⎥⎣⎦⎰⎰ ,其中122222d 1412F f Gq g λζλμπγ⎡⎤⎛⎫-+⎢⎥⎪+⎢⎥⎝⎭=⎢⎥∆⎢⎥⎢⎥⎣⎦其余见1)中计算式2.程序清单1)f0=1.5;zeta=0.25;gamma=9;mu=10;fs=3;zeta_s=0.25;u=20;Gq_n0=2.56*10^(-8);n0=0.1;delta_f=0.2;N=180;f=delta_f*[1:N];omega=2*pi*f;omega0=2*pi*f0;omega_s=2*pi*fs;lambda=omega./omega0;lambda_s=omega./omega_s;%计算并绘制幅频特性delta=((1-lambda.^2).*(1+gamma-1./mu.*lambda.^2)-1).^2+4*zeta^2.*lambda.^...2.*(gamma-(1./mu+1).*lambda.^2).^2;z1_q=gamma.*(((1-lambda.^2).^2+4*zeta.^2.*lambda.^2)./delta).^0.5;z2_z1=((1+4*zeta.^2.*lambda.^2)./((1-lambda.^2).^2+4*zeta.^2.*lambda.^2))....^0.5;p_z2=((1+(2*zeta_s.*lambda_s).^2)./((1-lambda_s.^2).^2+(2*zeta_s.*...lambda_s).^2)).^0.5;figure(1)loglog(f,z1_q,'b-',0:0.1:100,(0:0.1:100)./(0:0.1:100),'g-');axis([0.1,100,0.1,10]);grid on ;title('z_1~q 的幅频特性');xlabel('激振频率f/Hz');ylabel('$$|\frac{z_1}{q}|$$','Interpreter','latex');gtext('0:1');figure(2)loglog(f,z2_z1,'b-',0:0.1:1,(0:0.1:1)./(0:0.1:1),'g-',1:0.1:100,1./...(1:0.1:100),'g-');axis([0.1,100,0.01,10]);grid on;title('z_2~z_1的幅频特性');xlabel('激振频率f/Hz');ylabel('$$|\frac{z_2}{z_1}|$$','Interpreter','latex'); gtext('0:1');gtext('-1:1');figure(3)loglog(f,p_z2,'b-');axis([0.1,100,0.01,10]);grid on;title('p~z_2的幅频特性');xlabel('激振频率f/Hz');ylabel('$$|\frac{p}{z_2}|$$','Interpreter','latex');%计算并绘制均方根谱sqrt_Gq=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u);sqrt_Gz1=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z1_q;sqrt_Gz2=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z2_z1.*z1_q;sqrt_Ga=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*p_z2.*z2_z1.*z1_q; figure(4)loglog(f,sqrt_Gz1,'b-');grid on;title('车轮位移均方根谱');xlabel('激振频率f/Hz');ylabel('$\sqrt{G_{z''''1}(f)}$','Interpreter','latex'); figure(5)loglog(f,sqrt_Gz2,'b-');grid on;title('车身位移均方根谱');xlabel('激振频率f/Hz');ylabel('$\sqrt{G_{z''''2}(f)}$','Interpreter','latex'); figure(6)loglog(f,sqrt_Ga,'b-');grid on;title('传至人体的位移均方根谱');xlabel('激振频率f/Hz');ylabel('$\sqrt{G_a(f)}$','Interpreter','latex');%计算其它值sigma_q=sqrt(trapz(f,sqrt_Gq.^2));%路面不平度加速度均方根值sigma_z1=sqrt(trapz(f,sqrt_Gz1.^2));%车轮加速度均方根值sigma_z2=sqrt(trapz(f,sqrt_Gz2.^2));%车身加速度均方根值sigma_a=sqrt(trapz(f,sqrt_Ga.^2));%传至人体的加速度均方根值for i=1:Nif f(i)<=2W(i)=0.5;elseif f(i)<=4W(i)=f(i)/4;elseif f(i)<=12.5W(i)=1;elseW(i)=12.5/f(i);endendaw=sqrt(trapz(f,W.^2.*sqrt_Ga.^2));%加权加速度均方根值a0=10^(-6);Law=20*log10(aw/a0);%加权振级format shortdisp('路面不平度加速度均方根值=');disp(sigma_q);disp('车轮加速度均方根值=');disp(sigma_z1);disp('车身加速度均方根值=');disp(sigma_z2);disp('传至人体的加速度均方根值=');disp(sigma_a);disp('加权加速度均方根值=');disp(aw);disp('加权振级=');disp(Law);2)%随fs变化f0=1.5;zeta=0.25;gamma=9;mu=10;fs=1.5:0.01:6;zeta_s=0.25;u=20;Gq_n0=2.56*10^(-8);n0=0.1;delta_f=0.2;N=180;f=delta_f*[1:N];omega=2*pi*f;omega0=2*pi*f0;lambda=omega./omega0;for i=1:length(fs)omega_s=2*pi.*fs(i);lambda_s=omega./omega_s;delta=((1-lambda.^2).*(1+gamma-1./mu.*lambda.^2)-1).^2+4*zeta^2.*lambda.^...2.*(gamma-(1./mu+1).*lambda.^2).^2;z1_q=gamma.*(((1-lambda.^2).^2+4*zeta.^2.*lambda.^2)./delta).^0.5;z2_z1=((1+4*zeta.^2.*lambda.^2)./((1-lambda.^2).^2+4*zeta.^2.*lambda.^2))....^0.5;p_z2=((1+(2*zeta_s.*lambda_s).^2)./((1-lambda_s.^2).^2+(2*zeta_s.*...lambda_s).^2)).^0.5;sqrt_Gq=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u);sqrt_Gz1=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z1_q;sqrt_Gz2=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z2_z1.*z1_q;sqrt_Ga=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*p_z2.*z2_z1.*z1_q;for j=1:Nif f(j)<=2W(j)=0.5;elseif f(j)<=4W(j)=f(j)/4;elseif f(j)<=12.5W(j)=1;elseW(j)=12.5/f(j);endendaw(i)=sqrt(trapz(f,W.^2.*sqrt_Ga.^2));enda0=10^(-6);Law=20*log10(aw/a0);figure(1)plot(fs,aw);grid ontitle('a_w随f_s的变化曲线');xlabel('f_s/Hz');ylabel('a_w/m·s^-^2');figure(2)plot(fs,Law);grid ontitle('L_aw随f_s的变化曲线');xlabel('f_s/Hz');ylabel('L_a_w/dB');%随zeta_s变化f0=1.5;zeta=0.25;gamma=9;mu=10;fs=3;zeta_ss=0.125:0.001:0.5;u=20;Gq_n0=2.56*10^(-8);n0=0.1;delta_f=0.2;N=180;f=delta_f*[1:N];omega=2*pi*f;omega0=2*pi*f0;omega_s=2*pi.*fs;lambda=omega./omega0;lambda_s=omega./omega_s;for i=1:length(zeta_ss)zeta_s=zeta_ss(i);delta=((1-lambda.^2).*(1+gamma-1./mu.*lambda.^2)-1).^2+4*zeta^2.*lambda.^...2.*(gamma-(1./mu+1).*lambda.^2).^2;z1_q=gamma.*(((1-lambda.^2).^2+4*zeta.^2.*lambda.^2)./delta).^0.5;z2_z1=((1+4*zeta.^2.*lambda.^2)./((1-lambda.^2).^2+4*zeta.^2.*lambda.^2))....^0.5;p_z2=((1+(2*zeta_s.*lambda_s).^2)./((1-lambda_s.^2).^2+(2*zeta_s.*...lambda_s).^2)).^0.5;sqrt_Gq=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u);sqrt_Gz1=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z1_q;sqrt_Gz2=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z2_z1.*z1_q;sqrt_Ga=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*p_z2.*z2_z1.*z1_q;for j=1:Nif f(j)<=2W(j)=0.5;elseif f(j)<=4W(j)=f(j)/4;elseif f(j)<=12.5W(j)=1;elseW(j)=12.5/f(j);endendaw(i)=sqrt(trapz(f,W.^2.*sqrt_Ga.^2));enda0=10^(-6);Law=20*log10(aw/a0);figure(1)plot(zeta_ss,aw);grid ontitle('a_w随\zeta_s的变化曲线');xlabel('\zeta_s');ylabel('a_w/m·s^-^2');figure(2)plot(zeta_ss,Law);grid ontitle('L_aw随\zeta_s的变化曲线');xlabel('\zeta_s');ylabel('L_a_w/dB');3)%随f0变化f0=0.25:0.01:3;zeta=0.25;gamma=9;mu=10;fs=3;zeta_s=0.25;u=20;Gq_n0=2.56*10^(-8);n0=0.1;delta_f=0.2;N=180;f=delta_f*[1:N];omega=2*pi*f;omega_s=2*pi*fs;lambda_s=omega./omega_s;Gq_f=4*pi^2*Gq_n0*n0^2*u;g=9.8;for i=1:length(f0)omega0=2*pi*f0(i);lambda=omega./omega0;delta=((1-lambda.^2).*(1+gamma-1./mu.*lambda.^2)-1).^2+4*zeta^2.*lambda.^...2.*(gamma-(1./mu+1).*lambda.^2).^2;z1_q=gamma.*(((1-lambda.^2).^2+4*zeta.^2.*lambda.^2)./delta).^0.5;z2_z1=((1+4*zeta.^2.*lambda.^2)./((1-lambda.^2).^2+4*zeta.^2.*lambda.^2))....^0.5;sqrt_Gz2=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z2_z1.*z1_q;sigma_z2(i)=sqrt(trapz(f,sqrt_Gz2.^2));fd_q=gamma*lambda.^2./(2*pi.*f).*(1./delta).^0.5;sigma_fd(i)=sqrt(trapz(f,Gq_f.*fd_q.^2));Fd_Gq=2*pi.*f.*gamma./g.*(((lambda.^2./(1+mu)-1).^2+4*zeta.^2*lambda.^2)..../delta).^0.5;sigma_FdG(i)=sqrt(trapz(f,Gq_f.*Fd_Gq.^2));endm=find(f0==1.5);sgm_z2=sigma_z2(m);sgm_fd=sigma_fd(m);sgm_FdG=sigma_FdG(m);sm_z2=20*log10(sigma_z2/sgm_z2);sm_fd=20*log10(sigma_fd/sgm_fd);sm_FdG=20*log10(sigma_FdG/sgm_FdG);plot(f0,sm_z2,f0,sm_fd,f0,sm_FdG);axis([0.25,3,-25,10]);grid on;title('各响应量均方根值随f_0变化的曲线');xlabel('f_0/Hz');ylabel('\sigma_z_''_''_2,\sigma_f_d,\sigma_F_d_/_G/dB'); legend('\sigma_z_''_''_2','\sigma_f_d','\sigma_F_d_/_G');legend('Location','southeast');%随zeta变化f0=1.5;zeta0=0.125:0.001:0.5;gamma=9;mu=10;fs=3;zeta_s=0.25;u=20;Gq_n0=2.56*10^(-8);n0=0.1;delta_f=0.2;N=180;f=delta_f*[1:N];omega=2*pi*f;omega_s=2*pi*fs;omega0=2*pi*f0;lambda_s=omega./omega_s;lambda=omega./omega0;Gq_f=4*pi^2*Gq_n0*n0^2*u;g=9.8;for i=1:length(zeta0)zeta=zeta0(i);delta=((1-lambda.^2).*(1+gamma-1./mu.*lambda.^2)-1).^2+4*zeta^2.*lambda.^...2.*(gamma-(1./mu+1).*lambda.^2).^2;z1_q=gamma.*(((1-lambda.^2).^2+4*zeta.^2.*lambda.^2)./delta).^0.5;z2_z1=((1+4*zeta.^2.*lambda.^2)./((1-lambda.^2).^2+4*zeta.^2.*lambda.^2))....^0.5;sqrt_Gz2=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z2_z1.*z1_q;sigma_z2(i)=sqrt(trapz(f,sqrt_Gz2.^2));fd_q=gamma*lambda.^2./(2*pi.*f).*(1./delta).^0.5;sigma_fd(i)=sqrt(trapz(f,Gq_f.*fd_q.^2));Fd_Gq=2*pi.*f.*gamma./g.*(((lambda.^2./(1+mu)-1).^2+4*zeta.^2*lambda.^2)..../delta).^0.5;sigma_FdG(i)=sqrt(trapz(f,Gq_f.*Fd_Gq.^2));endm=find(zeta0==0.25);sgm_z2=sigma_z2(m);sgm_fd=sigma_fd(m);sgm_FdG=sigma_FdG(m);sm_z2=20*log10(sigma_z2/sgm_z2);sm_fd=20*log10(sigma_fd/sgm_fd);sm_FdG=20*log10(sigma_FdG/sgm_FdG);plot(zeta0,sm_z2,zeta0,sm_fd,zeta0,sm_FdG);axis([0.125,0.5,-4,4]);grid on;title('各响应量均方根值随\zeta变化的曲线');xlabel('\zeta');ylabel('\sigma_z_''_''_2,\sigma_f_d,\sigma_F_d_/_G/dB'); legend('\sigma_z_''_''_2','\sigma_f_d','\sigma_F_d_/_G');%随gamma变化f0=1.5;zeta=0.25;gamma0=4.5:0.1:18;mu=10;fs=3;zeta_s=0.25;u=20;Gq_n0=2.56*10^(-8);n0=0.1;delta_f=0.2;N=180;f=delta_f*[1:N];omega=2*pi*f;omega_s=2*pi*fs;omega0=2*pi*f0;lambda_s=omega./omega_s;lambda=omega./omega0;Gq_f=4*pi^2*Gq_n0*n0^2*u;g=9.8;for i=1:length(gamma0)gamma=gamma0(i);delta=((1-lambda.^2).*(1+gamma-1./mu.*lambda.^2)-1).^2+4*zeta^2.*lambda.^...2.*(gamma-(1./mu+1).*lambda.^2).^2;z1_q=gamma.*(((1-lambda.^2).^2+4*zeta.^2.*lambda.^2)./delta).^0.5;z2_z1=((1+4*zeta.^2.*lambda.^2)./((1-lambda.^2).^2+4*zeta.^2.*lambda.^2))....^0.5;sqrt_Gz2=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z2_z1.*z1_q;sigma_z2(i)=sqrt(trapz(f,sqrt_Gz2.^2));fd_q=gamma*lambda.^2./(2*pi.*f).*(1./delta).^0.5;sigma_fd(i)=sqrt(trapz(f,Gq_f.*fd_q.^2));Fd_Gq=2*pi.*f.*gamma./g.*(((lambda.^2./(1+mu)-1).^2+4*zeta.^2*lambda.^2)..../delta).^0.5;sigma_FdG(i)=sqrt(trapz(f,Gq_f.*Fd_Gq.^2));endm=find(gamma0==9);sgm_z2=sigma_z2(m);sgm_fd=sigma_fd(m);sgm_FdG=sigma_FdG(m);sm_z2=20*log10(sigma_z2/sgm_z2);sm_fd=20*log10(sigma_fd/sgm_fd);sm_FdG=20*log10(sigma_FdG/sgm_FdG);plot(gamma0,sm_z2,gamma0,sm_fd,gamma0,sm_FdG);axis([4.5,18,-6,6]);grid on;title('各响应量均方根值随\gamma变化的曲线');xlabel('\gamma');ylabel('\sigma_z_''_''_2,\sigma_f_d,\sigma_F_d_/_G/dB'); legend('\sigma_z_''_''_2','\sigma_f_d','\sigma_F_d_/_G');legend('Location','southeast');%随mu变化f0=1.5;zeta=0.25;gamma=9;mu0=5:0.1:20;fs=3;zeta_s=0.25;u=20;Gq_n0=2.56*10^(-8);n0=0.1;delta_f=0.2;N=180;f=delta_f*[1:N];omega=2*pi*f;omega_s=2*pi*fs;omega0=2*pi*f0;lambda_s=omega./omega_s;lambda=omega./omega0;Gq_f=4*pi^2*Gq_n0*n0^2*u;g=9.8;for i=1:length(mu0)mu=mu0(i);delta=((1-lambda.^2).*(1+gamma-1./mu.*lambda.^2)-1).^2+4*zeta^2.*lambda.^...2.*(gamma-(1./mu+1).*lambda.^2).^2;z1_q=gamma.*(((1-lambda.^2).^2+4*zeta.^2.*lambda.^2)./delta).^0.5;z2_z1=((1+4*zeta.^2.*lambda.^2)./((1-lambda.^2).^2+4*zeta.^2.*lambda.^2))....^0.5;sqrt_Gz2=4*pi^2.*f.*sqrt(Gq_n0*n0^2*u).*z2_z1.*z1_q;sigma_z2(i)=sqrt(trapz(f,sqrt_Gz2.^2));fd_q=gamma*lambda.^2./(2*pi.*f).*(1./delta).^0.5;sigma_fd(i)=sqrt(trapz(f,Gq_f.*fd_q.^2));Fd_Gq=2*pi.*f.*gamma./g.*(((lambda.^2./(1+mu)-1).^2+4*zeta.^2*lambda.^2)..../delta).^0.5;sigma_FdG(i)=sqrt(trapz(f,Gq_f.*Fd_Gq.^2));endm=find(mu0==10);sgm_z2=sigma_z2(m);sgm_fd=sigma_fd(m);sgm_FdG=sigma_FdG(m);sm_z2=20*log10(sigma_z2/sgm_z2);sm_fd=20*log10(sigma_fd/sgm_fd);sm_FdG=20*log10(sigma_FdG/sgm_FdG);plot(mu0,sm_z2,mu0,sm_fd,mu0,sm_FdG);axis([5,20,-2,2]);grid on;title('各响应量均方根值随\mu变化的曲线');xlabel('\mu');ylabel('\sigma_z_''_''_2,\sigma_f_d,\sigma_F_d_/_G/dB');legend('\sigma_z_''_''_2','\sigma_f_d','\sigma_F_d_/_G');3.结果分析1)路面不平度加速度均方根值=0.3523车轮加速度均方根值=0.2391车身加速度均方根值=0.0168传至人体的加速度均方根值=0.0161加权加速度均方根值=0.0100加权振级=80.0287分析:根据课本中表6-2,a w=0.0100<0.315,L aw=80.0287<110,故乘客没有不舒适。

汽车理论 matlab编程 作业答案

汽车理论 matlab编程 作业答案

4.3(1)利用附着系数空载时前轴的利用附着系数φf1:φf1=βz1L b+zh g=0.38z13.951.85+0.845z空载时后轴的利用附着系数φr1:φr1=(1−β)z1L a−zh g=(1−0.38)z13.952.1−0.845z满载时前轴的利用附着系数φf2:φf2=βz1L b+zh g=0.38z13.951.0+1.17z满载时后轴的利用附着系数φr2:φr2=(1−β)z1L a−zh g=(1−0.38)z13.952.95−1.17zMatlab程序:clcclearsyms z;f1=0.38*z/((1/3.95)*(1.85+0.845*z));r1=(1-0.38)*z/((1/3.95)*(2.1-0.845*z)); f2=0.38*z/((1/3.95)*(1.0+1.17*z));r2=(1-0.38)*z/((1/3.95)*(2.95-1.17*z)); f=z;ezplot(f1);hold on;ezplot(f2);ezplot(r1);ezplot(r2);ezplot(f);axis([0 1.0 0 1.0]);title('利用附着系数曲线');xlabel('制动强度z');ylabel('利用附着系数');text(0.38,0.8,'Ør(空载)');text(0.6,0.9,'Ør(满载)');text(0.8,0.45,'Øf(空载)');text(0.8,0.6,' Øf(满载)');text(0.85,0.9,'Ø=z')制动效率空载时前轴的制动效率E f1:E f1=bLβ−φf gL=1.85/3.95f空载时后轴的制动效率E r1:E r1=aL(1−β)−φr gL=2.1/3.95r满载时前轴的制动效率E f2:E f2=bLβ−φf gL=1.0/3.950.38−φf∙1.17/3.95满载时后轴的制动效率E r2:E r2=aL(1−β)−φr gL=2.95/3.95rMatlab程序:clearsyms x;Er1=2.1/3.95/(1-0.38+x*0.845/3.95); Ef2=1.0/3.95/(0.38-x*1.17/3.95);Er2=2.95/3.95/(1-0.38+x*1.17/3.95); ezplot(Ef2);hold on;ezplot(Er1);ezplot(Er2);axis([0 1.0 0 1.0]);title('前后轴制动效率曲线'); xlabel('附着系数'); ylabel('制动效率(%)'); text(0.35,0.9,'Ef'); text(0.8,0.9,'Er'); text(0.55,0.78,'Er'); text(0.65,0.94,'满载'); text(0.55,0.65,'空载');(2)①由图可得:空载时,在φ=0.8时的制动效率为0.7,则其制动减速度为0.8g*0.7=0.56g 。

汽车理论课后作业matlab编程详解(带注释)

汽车理论课后作业matlab编程详解(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 1.000.793];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).^3-3.84 45*(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',ua4,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。

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。

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1.3和2.7matlab编程答案

汽车理论1.3和2.7matlab编程答案

孙野 200812681.3(1)绘制汽车驱动力与行驶阻力平衡图 选用5挡变速器进行整车性能计算发动机转速与汽车行驶速度之间的关系:0377.0i i rn u g a = 发动机使用外特性的T q -n 曲线拟合公式:432)1000(8445.3)1000(874.40)1000(44.165)1000(27.295313.19n n n n T q -+-+-=汽车驱动力:ri i T F Tg q t η0=行驶阻力:2215.2115.21a D a D j w i f u A C mgf dt du m u A C Gi Gf F F F F +=+++=+++δ用matlab 编写程序如下: m1=2000; m2=1800; mz=3880; g=9.81; r=0.367; CdA=2.77; f=0.013; nT=0.85; ig=[5.56 2.769 1.644 1.00 0.793];i0=5.83; If=0.218; Iw1=1.798; Iw2=3.598; %输入已知参数 Iw=2*Iw1+4*Iw2; fori=1:69n(i)=(i+11)*50;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; end %从600~4000rpm 油拟合公式计算发动机转距 for j=1:5 fori=1:69Ft(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;endend%计算各档位下的驱动力和行驶阻力plot(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)');%作汽车驱动力与行驶阻力平衡图得到汽车驱动力与行驶阻力平衡图如下:(2)①计算汽车最高车速Matlab程序如下:for k=1:175 n1(k)=3300+k*0.1;Ttq(k)=-19.313+295.27*(n1(k)/1000)-165.44*(n1(k)/1000)^2+40.874*(n1(k)/1000)^33.8445*(n1(k)/1000)^4;Ft(k)=Ttq(k)*ig(5)*i0*nT/r;ua(k)=0.377*r*n1(k)/(ig(5)*i0);Fz(k)=CdA*ua(k)^2/21.15+mz*g*f;E(k)=abs((Ft(k)-Fz(k)));end%从3300rpm开始以0.1rpm为步长搜索直到找到for k=1:175 %驱动力与行驶阻力之差绝对值最小点(Ⅴ档处) if(E(k)==min(E))%通过其他检验程序可估计出该点大致位置(3310rpm附近) disp('汽车最高车速='); disp(ua(k));disp('km/h');end%输出结果end汽车最高车速=98.7627km/h计算得汽车最高车速为98.7627km/h。

汽车理论课后习题Matlab程序详解

汽车理论课后习题Matlab程序详解

陕西理工学院杨飞华1 / 341.3 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()1000100010001000qnnnnT=?+?+?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nmin=600r/min,最高转速nmax=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CDA=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 Iw2=3.598kg?m2 变速器传动比 ig(数据如下表)Ⅰ档Ⅱ档Ⅲ档Ⅳ档Ⅴ档四档变速器 6.09 3.09 1.71 1.00 - 五档变速器 5.56 2.769 1.644 1.00 0.793 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;2 / 34Ft4=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/h3 / 34(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;4 / 34Fw4=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=0.42195 / 34(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/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/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武汉理工大学6 / 340)^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。

(完整word版)汽车理论课后作业matlab编程详解(带注释)(word文档良心出品)

(完整word版)汽车理论课后作业matlab编程详解(带注释)(word文档良心出品)

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 1.000.793];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).^3-3.84 45*(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',ua4,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。

(完整版)汽车理论课后作业答案MATLAB

(完整版)汽车理论课后作业答案MATLAB

汽车理论作业 MA TLAB 过程010203040506070809010050001000015000汽车驱动力与阻力平衡图u a /km.h -1F /N10203040506070809010002468101214加速度倒数-速度曲线图u1/a0102030405060708090100102030405060u/(km/h)P /k W汽车功率平衡图10203040506070809010012141618202224最高档等速百公里油耗曲线Ua/(km/h)Q s /L2324252627282912131415161718燃油积极性-加速时间曲线燃油经济性(qs/L)动力性--原地起步加速时间 (s t /s )源程序:《第一章》m=3880; g=9.8; r=0.367; x=0.85; f=0.013; io=5.83; CdA=2.77; If=0.218; Iw1=1.798; Iw2=3.598; Iw=Iw1+Iw2;ig=[6.09 3.09 1.71 1.00]; %变速器传动比 L=3.2; a=1.947; hg=0.9; n=600:1:4000;T=-19.313+295.27*n/1000-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4; Ft1=T*ig(1)*io*x/r;%计算各档对应转速下的驱动力Ft2=T*ig(2)*io*x/r;Ft3=T*ig(3)*io*x/r;Ft4=T*ig(4)*io*x/r;u1=0.377*r*n/(io*ig(1));u2=0.377*r*n/(io*ig(2));u3=0.377*r*n/(io*ig(3));u4=0.377*r*n/(io*ig(4));u=0:130/3400:130;F1=m*g*f+CdA*u1.^2/21.15;%计算各档对应转速下的驱动阻力F2=m*g*f+CdA*u2.^2/21.15;F3=m*g*f+CdA*u3.^2/21.15;F4=m*g*f+CdA*u4.^2/21.15;figure(1);plot(u1,Ft1,'-r',u2,Ft2,'-m',u3,Ft3,'-k',u4,Ft4,'-b',u1,F1,'-r',u2,F2,'-m',u3,F3,'-k',u4,F4,'-b','LineWidth',2)title('汽车驱动力与阻力平衡图');xlabel('u_{a}/km.h^{-1}')ylabel('F/N')gtext('F_{t1}')gtext('F_{t2}')gtext('F_{t3}')gtext('F_{t4}')gtext('F_{f}+F_{w}')%由汽车驱动力与阻力平衡图知,他们无交点,u4在最大转速时达到最大umax=u4(3401)Ft1max=max(Ft1);imax=(Ft1max-m*g*f)/(m*g)disp('假设是后轮驱动');C=imax/(a/L+hg*imax/L) % 附着率delta1=1+(Iw1+Iw2)/(m*r^2)+If*ig(1)*r^2*io^2*x/(m*r^2);delta2=1+(Iw1+Iw2)/(m*r^2)+If*ig(2)*r^2*io^2*x/(m*r^2);delta3=1+(Iw1+Iw2)/(m*r^2)+If*ig(3)*r^2*io^2*x/(m*r^2);delta4=1+(Iw1+Iw2)/(m*r^2)+If*ig(4)*r^2*io^2*x/(m*r^2);a1=(Ft1-F1)/(delta1*m); %加速度a2=(Ft2-F2)/(delta2*m);a3=(Ft3-F3)/(delta3*m);a4=(Ft4-F4)/(delta4*m);h1=1./a1; %加速度倒数h2=1./a2;h3=1./a3;h4=1./a4;figure(2);plot(u1,h1,u2,h2,u3,h3,u4,h4,'LineWidth',2); title('加速度倒数-速度曲线图');xlabel('u')ylabel('1/a')gtext('1/a1')gtext('1/a2')gtext('1/a3')gtext('1/a4')%由加速度倒数-速度曲线图可知u1min=min(u1);u1max=max(u1);u2min=u1max;u2min=min(u2);u2max=max(u2);u3min=u2max;u3max=max(u3);u4min=u3max;u4max=70;x1=[];x2=[];x3=[];x4=[];y=3401;for i=1:3401;if u3(i)<=u3min;x1=[i];endendq1=max(x1);ua3=u3(q1:y);a3=h3(q1:y);for i=1:3401;if u4(i)<=u4min;x2=[i];elseif u4(i)<=u4max;x3=[i];endendq2=max(x2);q3=max(x3);ua4=u4(q2:q3);a4=h4(q2:q3);s1=trapz(h2,u2 ); %二挡运行时间s2=trapz(ua3,a3);s3=trapz(ua4,a4);s=[s1 s2 s3];disp('积分得')t=sum(s)*1000/3600 %总时间《第二章》Pe1=Ft1.*u1./3600;%计算各档对应转速下的功率Pe2=Ft2.*u2./3600;Pe3=Ft3.*u3./3600;Pe4=Ft4.*u4./3600;P1=F1.*u1./(3600*x);%计算各档对应的各个车速下的行驶功率P2=F2.*u2./ (3600*x);P3=F3.*u3./ (3600*x);P4=F4.*u4./ (3600*x);figure(3);plot(u1,Pe1,'-r',u2,Pe2,'-m',u3,Pe3,'-k',u4,Pe4,'-b',u1,P1,'k',u2,P2,'k',u3,P3,'k', u4,P4,'k','linewidth',2);gtext('Pe1')gtext('Pe2')gtext('Pe3')gtext('Pe4')xlabel('u/(km/h)');ylabel('P/kW');title('汽车功率平衡图');n=[815 1207 1614 2012 2603 3006 3403 3804];Ua=[];Ua=0.377*r*n./(io*ig(4))ft=[];ft=m*g*f+(2.77/21.15)*Ua.^2;%计算各转速对应的各个车速下的行驶阻力Pe(1)=ft(1).*Ua(1)./(3600*x);%计算各转速对应的各个车速下的行驶阻力功率Pe(2)=ft(2).*Ua(2)./(3600*x);Pe(3)=ft(3).*Ua(3)./(3600*x);Pe(4)=ft(4).*Ua(4)./(3600*x);Pe(5)=ft(5).*Ua(5)./(3600*x);Pe(6)=ft(6).*Ua(6)./(3600*x);Pe(7)=ft(7).*Ua(7)./(3600*x);Pe(8)=ft(8).*Ua(8)./(3600*x)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=[72.739 36.657 14.525 7.0035 4.4763 2.8593 2.9788 0.7113];B3=[-5.8629 -2.0533 -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];b1=(B0(1))+(B1(1)*Pe(1))+(B2(1)*Pe(1)^2)+(B3(1)*Pe(1)^3)+(B4(1)*Pe(1)^4);b2=(B0(2))+(B1(2)*Pe(2))+(B2(2)*Pe(2)^2)+(B3(2)*Pe(2)^3)+(B4(2)*Pe(2)^4);b3=(B0(3))+(B1(3)*Pe(3))+(B2(3)*Pe(3)^2)+(B3(3)*Pe(3)^3)+(B4(3)*Pe(3)^4);b4=(B0(4))+(B1(4)*Pe(4))+(B2(4)*Pe(4)^2)+(B3(4)*Pe(4)^3)+(B4(4)*Pe(4)^4);b5=(B0(5))+(B1(5)*Pe(5))+(B2(5)*Pe(5)^2)+(B3(5)*Pe(5)^3)+(B4(5)*Pe(5)^4);b6=(B0(6))+(B1(6)*Pe(6))+(B2(6)*Pe(6)^2)+(B3(6)*Pe(6)^3)+(B4(6)*Pe(6)^4);b7=(B0(7))+(B1(7)*Pe(7))+(B2(7)*Pe(7)^2)+(B3(7)*Pe(7)^3)+(B4(7)*Pe(7)^4);b8=(B0(8))+(B1(8)*Pe(8))+(B2(8)*Pe(8)^2)+(B3(8)*Pe(8)^3)+(B4(8)*Pe(8)^4);p=0.7;Qs=[];Qs(1)=(Pe(1)*b1)/(1.02*Ua(1).*p*g);Qs(2)=(Pe(2)*b2)/(1.02*Ua(2).*p*g);Qs(3)=(Pe(3)*b3)/(1.02*Ua(3).*p*g);Qs(4)=(Pe(4)*b4)/(1.02*Ua(4).*p*g);Qs(5)=(Pe(5)*b5)/(1.02*Ua(5).*p*g);Qs(6)=(Pe(6)*b6)/(1.02*Ua(6).*p*g);Qs(7)=(Pe(7)*b7)/(1.02*Ua(7).*p*g);Qs(8)=(Pe(8)*b8)/(1.02*Ua(8).*p*g);M=polyfit(Ua,Qs,2);UA=0.377*r*600/(ig(4)*io):1:0.377*r*4000/(ig(4)*io);%UA表示车速QS=polyval(M,UA);%QS表示油耗figure(4);plot(UA,QS,'linewidth',2);title('最高档等速百公里油耗曲线');xlabel('Ua/(km/h)');ylabel('Qs/L');《第三章》io=[5.17 5.43 5.83 6.17 6.33];Va=0.377*r*n(7)./(io.*ig(4));Ps=46.9366;disp('假设以最高档,较高转速(n取3401 ),最经济负荷(即90%负荷大约 46.9366Kw)行驶时油耗')qs=[];qs(1)=(Ps*b7)/(1.02*Va(1).*p*g);qs(2)=(Ps*b7)/(1.02*Va(2).*p*g);qs(3)=(Ps*b7)/(1.02*Va(3).*p*g);qs(4)=(Ps*b7)/(1.02*Va(4).*p*g);qs(5)=(Ps*b7)/(1.02*Va(5).*p*g);st=[ 17.5813 16.2121 14.5126 13.3775 12.9185];%加速时间:(这里以最高档〈四档〉、速度由0加速到94.93Km/h 的时间)因与题1.3第三问求法相同,这里不在累述,可直接有计算机求得:figure(5);plot(qs,st,'+','linewidth',2)hold on plot(qs,st,); gtext('5.17') gtext('5.43') gtext('5.83') gtext('6.17') gtext('6.33')title('燃油积极性-加速时间曲线'); xlabel('燃油经济性(qs/L)');ylabel('动力性--原地起步加速时间 (st/s)');《第四章》 4-31)前轴利用附着系数为:gf zh b zL +=βϕ后轴利用附着系数为: ()gr zh a zL --=βϕ1空载时:g h b L -=βϕ0=413.0845.085.138.095.3-=-⨯所以0ϕϕ>空载时后轮总是先抱死。

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。

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end
end
figure(1);
plot(Ua,Ft,Ua,Fz,'--','LineWidth',2) %作汽车驱动力与行驶阻力平衡图
axis([0 125 0 14500]);
title('汽车驱动力-行驶阻力平衡图');
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*yitaT/r;
inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));
delta(i)=deta_u*inv_a(i)/3.6;
else
n=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;
ig=[5.56 2.769 1.644 1.00 0.793]; %1档至5档变速箱传动比
If=0.218;
Iw1=1.798;
Iw2=3.598;
a=1.947;
L=3.2;
hg=0.9;
Iw=2*Iw1+4*Iw2;
legend('Ft1','Ft2','Ft3','Ft4','Ft5','Ff+Fw')
xlabel('Ua/(km/h)');
ylabel('Ft/(N)');
gtext('F_{t1}');
gtext('F_{t2}');
gtext('F_{t3}');
for i=1:341
Ua(i,j)=0.377*r*nmin/ig(j)/i0;
Ua(i,j)=0.377*r*nmax/ig(j)/i0;
deta=0*ig;
for i=1:5
deta(i)=1+(Iw1+Iw2)/(m*r^2)+(If*(ig(i))^2*i0^2*yitaT)/(m*r^2);
end
plot(t,ua),grid
axis([0 100 0 60])
title('汽车加速时间曲线')
xlabel('t-s')
ylabel('ua-km/h')
nmin=600;
nmax=4000;
for i=1:341
n(i)=(i+59)*10; %对应转速600-4000rpm
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;
for j=1:5
for i=1:341
h(i,j)=1/a(i,j); %加速度倒数
end
end
figure(2);
plot(Ua,h,'LineWidth',2);
end
for j=1:5
for i=1:341
Ft(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;%计算各档位下的驱动力和行驶阻力
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*yitaT/r;
inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i));
Ft=Tq*ig(5)*i0*yitaT/r;
inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));
delta(i)=deta_u*inv_a(i)/3.6;
end
a=delta(1:k);
t(i)=sum(a);
% for l=1:341
% mm(l)=min(m(l));
% Uam =Ua(l,5);
% end
%end
% disp(Uam);
Ft1max=max(Ft(:,1));
m1=2000; %初始化参数
m2=1800;
mz=3880;
g=9.81;
r=0.367;
nT=0.85;
f=0.013;
CDA=2.77;
i0=5.83;
Ft=Tq*ig(3)*i0*yitaT/r;
inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));
delta(i)=deta_u*inv_a(i)/3.6;
elseif ua(i)<=u2(4)
n=ua(i)*(ig(4)*i0/r)/0.377;
axis([0 98 0 14]);
title('汽车的加速度倒数-速度曲线图');
legend('1/a1','1/a2','1/a3','1/a4','1/a5')
xlabel('Ua/(km/h)')
ylabel('1/a')
delta(i)=deta_u*inv_a(i)/3.6;
else if 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;
disp('后轮驱动');
disp(imax);
disp(Uamax)ห้องสมุดไป่ตู้
C=imax/(a/L+hg*imax/L) % 相应的附着率
for j=1:5
for i=1:341
for k=1:341
if (Ft(k,1)==Ft1max)
Uamax = Ua(k,1);
end
end
Fz1=CDA*Uamax^2/21.15+mz*g*f;
imax=(Ft1max-Fz1)/(mz*g);
gtext('1/a1')
gtext('1/a2')
gtext('1/a3')
gtext('1/a4')
gtext('1/a5')
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
for j=1:5
gtext('F_{t4}');
gtext('F_{t5}');
gtext('F_{f}+F_{w}');
% for l=1:341
% m(l) = abs( ( Ft(l,5)-Fz(l,5)));
% end
delta=1+Iw/(mz*r^2)+If*ig(j)^2*i0^2*nT/(mz*r^2);%相应的汽车旋转质量换算系数
a(i,j)=(Ft(i,j)- Fz(i,j))/(delta*mz); %汽车的行驶加速度
end
end
end
deta_u=0.01;
ua=[6:deta_u:99];N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;
for i=1:N
k=i;
if ua(i)<=u2(2)
n=ua(i)*(ig(2)*i0/r)/0.377;
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