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); end

for j=1:5

for i=1:56

Ft(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; end end

figure

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)'); 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); end for j=1:5 for i=1:56

Ft(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);

end end

x1=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);

figure

plot(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:N k=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; else

n=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; end

a=delta(1:k); t(i)=sum(a); end

plot(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=1:5

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);

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; end end

plot(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=1:5 for i=1:8

Pd(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); end end

b(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);