汽车理论课后题matlab程序

1.3

n=600:1:4000; r=0.367; i0=5.83; eff=0.85; f=0.013;

m=3880; g=9.8; G=m*g; CdA=2.77; a=1.947; hg=0.9; L=3.2;

Iw1=1.798; Iw2=3.598; Iw=Iw1+Iw2; If=0.218;

Ttq=-19.313+295.27*n/1000-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000) .^4;

%驱动力行驶阻力平衡图

for ig=[5.56,2.769,1.644,1.00,0.793]

Ua=0.377*r*n/ig/i0;

Ft=Ttq*ig*i0*eff/r;

plot(Ua,Ft);

hold on;

end

Ff=G*f;

ua=0:0.1:max(Ua);

Fw=CdA*ua.^2/21.15;

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=0.377*r*n/5.56/i0;

Ft=Ttq*5.56*i0*eff/r;

Fw=CdA*Ua.^2/21.15;

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=[5.56,2.769,1.644,1.00,0.793]

Ua=0.377*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.^2/21.15;

as=(Ft-(Ff+Fw))/q/m;

plot(Ua,1./as);

hold on;

end

axis([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)=0.377*r*600/i0/2.769;dt=0.01;w=1;t(1)=0;ig=2.769; while(u(w)<99.08)

n(w)=u(w)*ig*i0/0.377/r;

Ttq(w)=-19.313+295.27*n(w)/1000-165.44*(n(w)/1000)^2+40.874*(n(w)/1000)^3-3.8445*(n(w)/1000)^4;

Ft(w)=Ttq(w)*ig*i0*eff/r; Ff=G*f;

Fw(w)=CdA*u(w)^2/21.15;

q=1+Iw/(m*r^2)+If*ig^2*i0^2*eff/(m*r^2); a(w)=3.6*(Ft(w)-(Ff+Fw(w)))/q/m; u(w+1)=u(w)+a(w)*dt;

if(u(w+1)>=0.377*4000*r/2.769/i0) ig=1.644; end

if(u(w+1)>=0.377*4000*r/1.644/i0) ig=1.00; end

if(u(w+1)>=0.377*4000*r/1.00/i0) ig=0.793; end

t(w+1)=(w+1)*dt; w=w+1; end

figure;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);

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10行驶加速度倒数曲线

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1.8

Iw1=2.25; Iw2=2.25; Iw=Iw1+Iw2; If=0.25; m=1600; g=9.8;G=m*g; Ttqmax=140; i1=3.85; i0=4.08; eff=0.9; r=0.3; hg=0.63; b=1.25; L=2.7; 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;