汽车理论课后作业matlab编程详细讲解.docx
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汽车理论课后作业matlab编程详细讲解.docx
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汽车理论课后作业matlab编程详细讲解
1.3matlab
程序:
(1)
嗚区动力-行驶阻力平衡图
屮货车相关参数。
m=3880;
g=9.8;
nmin=600;
nmax=4000;
G=m*g;
ig=[5.562.7691.6441.000.793];y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;
L=3.2;a=1.947;hg=0.9;lf=0.218;lw仁1.798;lw2=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*(门/1000)人2+40.874*(门/1000)人3-3.8445*(门/1000)人4
J
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.A2/21.15;
Fz2=m*g*f+2.77*ua2.A2/21.15;
Fz3=m*g*f+2.77*ua3.A2/21.15;
Fz4=m*g*f+2.77*ua4.A2/21.15;
Fz5=m*g*f+2.77*ua5.A2/21.15;
嗚区动力-行驶阻力平衡图。
plot(ua1,Ft1,ua2,Ft2,ua3,Ft3,ua4,Ft4,ua5,Ft5,ua1,Fz1,
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。
[x,y]=ginput
(1);
disp('汽车最高车速=');disp(x);disp('km/h');
(2)
%气车最大爬坡度
clear
clc
%气车相关参数。
m=3880;
g=9.8;
nmin=600;
nmax=4000;
G=m*g;
ig=[5.562.7691.6441.000.793];y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;
L=3.2;a=1.947;hg=0.9;lf=0.218;lw仁1.798;lw2=3.598;
n=600:
10:
4000;
Tq=-19.313+295.27*(n/1000)-165.44*(门/1000)人2+40.874*(门/1000)人3-3.8445*(门/1000)人4
J
Ft仁Tq*ig
(1)*i0*y/r;%一档时爬坡能力最强。
ua1=0.377*r*n/ig
(1)/i0;
Ff=G*f;%滚动阻力。
Fw1=CdA*ua1.A2/21.15;淞气阻力。
Fz1=Ff+Fw1;
Fi1=Ft1-Fz1;
Fmax=max(Fi1/G);
imax=100*tan(asin(Fmax));
disp('汽车最大爬坡度=');
disp(imax),disp('%');
匚ommandWindow
汽车最大爬坡度二
35.2197
%
A»
(3)
%求汽车加速度倒数曲线和最大爬坡度显得附着率。
clear
clc
m=3880;%气车相关参数。
g=9.8;
nmin=600;
nmax=4000;
G=m*g;
ig=[5.562.7691.6441.000.793];
y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;
L=3.2;a=1.947;hg=0.9;lf=0.218;lw1=1.798;lw2=3.598;
n=600:
10:
4000;%发动机转速范围。
Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)A2+40.874*(n/1000)A3-3.8445*(n/1000)A4
Ft1=Tq*ig
(1)*iO*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)*iO*y/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.A2/21.15;
Fw2=CdA*ua2.A2/21.15;
Fw3=CdA*ua3.A2/21.15;
Fw4=CdA*ua4.A2/21.15;
Fw5=CdA*ua5.A2/21.15;
略档位下的驱动力
%各档位下的车速
%空气阻力
Ff=G*f;%滚动阻力
%求各档位下的汽车旋转质量换算系
q1=1+(lw1+lw2)/(m*rA2)+(lf*ig
(1)A2*iOA2*y)/(m*「A2);数。
q2=1+(lw1+lw2)/(m*「A2)+(lf*ig
(2)人2许0人2*丫)/口*「人2);q3=1+(lw1+lw2)/(m*「A2)+(lf*ig(3)人2许0人2*丫)/口*「人2);q4=1+(lw1+lw2)/(m*「A2)+(lf*ig(‘4)人2许0人2*丫)/口*「人2);q5=1+(lw1+lw2)/(m*rA2)+(lf*ig(5)A2*i0A2*y)/(m*rA2);
a1=(Ft1-Ff-Fw1)/(q1*m);%求岀汽车加速度。
a2=(Ft2-Ff-Fw2)/(q2*m);
a3=(Ft3-Ff-Fw3)/(q3*m);
a4=(Ft4-Ff-Fw4)/(q4*m);
a5=(Ft5-Ff-Fw5)/(q5*m);
ad1=1./a1;;%求加速度倒数。
ad2=1./a2;
ad3=1./a3;
ad4=1./a4;
ad5=1./a5;
%绘制加速度倒数曲线
Plot(ua1,ad1,ua2,ad2,ua3,ad3,ua4,ad4,ua5,ad5);
axis([0100010]);
title('汽车的加速度倒数曲线’);
xlabel('ua(km/h)');
ylabel('1/a');
legend('ad1','ad2','ad3','ad4','ad5')
9求最大爬坡度时的附着率。
Fz=Ft1-Ff-Fw1;
aa=asin(max(Fz)/G);%最大爬坡角度。
C=tan(aa)/(a/L+hg*tan(aa)/L);%附着率。
disp('假设后轮驱动,最大爬坡度相应的附着率=);
disp(C);
Figure1
CommandWindow
假设后轮驱动,最大u®城度相应的附着率二
0.4978
fr、、
(4)%求汽车2档原地起步换挡加速行驶至70km/h的加速时间
clear
nT=0.85;
r=0.367;
f=0.013;CDA=2.77;
i0=5.83;lf=0.218;
Iw1=1.798;lw2=3.598;
L=3.2;a=1.947;hg=0.9;
m=3880;g=9.8;
ig=[5.562.7691.6441.000.793];
G=m*g;
nmin=600;nmax=4000;
u1=0.377*r*nmin./ig/iO;
u2=0.377*r*nmax./ig/iO;
deta=O*ig;
fori=1:
5
deta(i)=1+(Iw1+Iw2)/(m*rA2)+(If*(ig(i))A2*i0A2*nT)/(m*rA2);
end
ua=6:
0.01:
99;N=length(ua);n=O;Tq=O;Ft=O;inv_a=0*ua;delta=0*ua;
Ff=G*f;
Fw=CDA*ua.A2/21.15;
fori=1:
N
k=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)A2+40.874*(n/1000)A3-3.8445*(n/1000)A4;
Ft=Tq*ig
(2)*iO*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)A2+40.874*(n/1000)A3-3.8445*(n/1000)A4;
Ft=Tq*ig(3)*iO*nT/r;
inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));
delta(i)=O.O1*inv_a(i)/3.6;
elseifua(i)<=u2⑷
n=ua(i)*(ig⑷*i0/r)/0.377;
Tq=-19.313+295.27*(n/1000)-165.44*("1000^2+40.874*("1000)7-3.8445*(n/1000)A4;
Ft=Tq*ig(4)*iO*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=-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;
end
a=delta(1:
k);
t(i)=sum(a);
end
plot(t,ua);
axis([0800100]);
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)');
2.7matlab程序:
%会制汽车功率平衡图
clear
%气车参数。
ig=[5.562.7691.6441.000.793];
y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;
L=3.2;a=1.947;hg=0.9;lf=0.218;lw1=1.798;lw2=3.598;m=3880;g=9.8;
G=m*g;
n=600:
10:
4000;
Tq=-19.313+295.27*(n/1000)-165.44*(门/1000)人2+40.874*(门/1000)人3-3.8445*(门/1000)人4
ua仁0.377*r*n/ig
(1)/i0;%各档位下的车速。
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;
P1=Tq.*ig
(1)*i0.*ua1./(3600*r);%各档位下发动机的输岀功率
P2=Tq.*ig
(2)*i0.*ua2./(3600*r);
P3=Tq.*ig(3)*i0.*ua3./(3600*r);
P4=Tq.*ig(4)*i0.*ua4./(3600*r);
P5=Tq.*ig(5)*i0.*ua5./(3600*r);
ua=0:
0.2:
120;
Ff=G*f;
Fw=CdA*ua.A2/21.15;
Pf=Ff*ua/3600;%克服滚动阻力的功率
Pw=Fw.*ua/3600;%克服空气阻力的功率。
P6=(Pf+Pw)./y;
plot(ua1,P1,ua2,P2,ua3,P3,ua4,P4,ua5,P5,ua,P6);%会制汽车功率平衡图。
axis([01200
100]);
title('汽车功率平衡图’);
xlabel('ua(km/h)');
ylabel('Pe(kw)');
legend('Pe1','Pe2','Pe3','Pe4','Pe5','P(Ff+Fw)')
(2)
%最高档与次高档等速百公里油耗曲线图clear
clc
n=600:
1:
4000;液车相关参数。
m=3880;g=9.8;
G=m*g;
ig=[5.562.7691.6441.000.793];
y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;
L=3.2;a=1.947;hg=0.9;lf=0.218;lw仁1.798;lw2=3.598;
n0=[8151207161420122603300634033804];
B00=[1326.81354.71284.41122.91141.01051.21233.91129.7];
B10=[-416.46-303.98-189.75-121.59-98.893-73.714-84.478-45.291];
B20=[72.37936.65714.5247.00354.47632.85932.97880.71113];
B30=[-5.8629-2.0553-0.51184-0.18517-0.091077-0.05138-0.047449-0.00075215];
B40=[0.177680.0430720.00681640.00185550.000689060.000350320.00028230
-0.000038568];
B0=spline(n0,B00,n);%插值拟合系数曲线
B1=spline(n0,B10,n);
B2=spline(n0,B20,n);
B3=spline(n0,B30,n);
B4=spline(n0,B40,n);
ua4=0.377*r*n/ig(4)/i0;%45档车速ua5=0.377*r*n/ig(5)/i0;
%45档空气阻力
Ff=G*f;%滚动阻力。
Fz4=Ff+CdA*(ua4.A2)/21.15;
Fz5=Ff+CdA*(ua5.A2)/21.15;
Pe4=Fz4.*ua4./(y*3.6*1000);%45档克服行驶阻力所需功率。
Pe5=Fz5.*ua5./(y*3.6*1000);
fori=1:
1:
3401%+算燃油消耗率。
b4(i)=B0(i)+B1(i)*Pe4(i)+B2(i)*Pe4(i).A2+B3(i)*Pe4(i).A3+B4(i)*Pe4(i).A4;
b5(i)=B0(i)+B1(i)*Pe5(i)+B2(i)*Pe5(i).A2+B3(i)*Pe5(i).A3+B4(i)*Pe5(i).A4;
endpg=7.0;
Q4=Pe4.*b4./(1.02.*ua4.*pg);%计算百公里油耗。
Q5=Pe5.*b5./(1.02.*ua5.*pg);
plot(ua4,Q4,ua5,Q5);淤制曲线。
axis([01001030]);
title('最高档与次高档等速百公里油耗曲线’);
xlabel('ua(km/h)');
ylabel('百公里油耗(L/100km)');
legend('4','5')
百公里油耗(L/100km)
—*hahjha223
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