1、汽车理论课后题matlab程序汽车理论课后题matlab程序1.3n=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
2、,0.793 Ua=0.377*r*n/ig/i0; Ft=Ttq*ig*i0*eff/r; plot(Ua,Ft); hold on;endFf=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
3、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*r2)+If*ig2*i02*eff/(m*r2); Ft=Ttq*ig*i0*eff
4、/r; Fw=CdA*Ua.2/21.15; 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)=0.377*r*600/i0/2.769;dt=0.01;w=1;t(1)=0;ig=2.769;while(u(w)=0.377*4000*r/2.769/i0) ig=1.644; end
5、 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;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);1.8Iw1=2.25; Iw2=2.25; Iw=Iw1+Iw2; If=0.25; m=1600;
6、 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*r2)+If*i12*i02*eff/(m*r2);Ft=Ttqmax*i1*i0*eff/r;a=Ft/q/m;q=a/g;C1=q/(b/L-hg/L*q);if(C10.6) disp(发动机转矩不能充分发挥);else disp(发动机转矩能够充分发挥);endb=(q/0.6+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);1.9Iw=3
7、.6; If=0.22; m=2152; g=9.8; r=0.367; eff=0.9; i4=1; i0=4.55;amax=0.75; Ua=50/3.6; CdA=1.5;q=1+Iw/(m*r2);f=q*0.59/3.6/g;disp(汽车在该路面上的滚动阻力系数);disp(f);q=1+Iw/(m*r2)+If*i42*i02*eff/(m*r2);D4max=f+q*amax/g;disp(最大动力因数);disp(D4max);Fw=CdA*Ua2/21.15;D1max=(D4max*G+Fw)*i1/i4/G;imax=tan(asin(D1max-f*sqrt(1-D
8、1max2+f2)/(1+f2);disp(最大爬坡度),disp(imax);2.7n=600:1:4000; r=0.367; i0=5.83; eff=0.85; f=0.013;CdA=2.77;m=3880; g=9.8; G=m*g;Ttq=-19.313+295.27*n/1000-165.44*(n/1000).2+40.874*(n/1000).3-3.8445*(n/1000).4;for ig=5.56,2.769,1.644,1.00,0.793 Ua=0.377*r*n/ig/i0; Pe=Ttq.*n/9550; plot(Ua,Pe); hold on;endUa
9、=0:0.1: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=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.
10、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;B0=spline(n1,b0,n); B1=spline(n1,b1,n); B2=spline(n1,b2,n); B3=spline(n1,b3,n); B4
11、=spline(n1,b4,n);deng=7;figure;for ig=1.00,0.793 Ua=0.377*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./(1.02*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);4.3beta=0.38;
12、L=3.95; a1=2.1; b1=L-a1; hg1=0.845;a2=2.95; b2=L-a2; hg2=1.17;g=9.8;z=0:0.01:1;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=0:0.01:1;Ef1=(b1/L)./(beta-fai*hg1/L);Er1=(
13、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=0.8;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=0.02; t22=0.2; u0=30;s1=1/3.6*(t21+t2
14、2/2)*u0+u02/25.92/abmax1;s2=1/3.6*(t21+t22/2)*u0+u02/25.92/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=1/3.6*(t21+t22/2)*u0+u02/25.92/abmax1;s2=1/3.6*(t21+t22/2)*u0+u02/25.92/abmax2;disp(前部管路损坏时空载制动距离);di
15、sp(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=1/3.6*(t21+t22/2)*u0+u02/25.92/abmax1;s2=1/3.6*(t21+t22/2)*u0+u02/25.92/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);4.5hg=0.63; b=1.25; L=2.7; beta=0.65; fai=
16、0.7; g=9.8;fai0=(L*beta-b)/hg;if(faifai0) disp(前轮先抱死,制动效率为); E=(b/L)/(beta-fai*hg/L);else disp(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0.35,0.5,0.5);disp(1回路失效时，a)、b)、c)的制动系增益分别为0.65,0.5,0.5);disp(a)中1回路失效时最大
17、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。但是，c在一个回路失效时，制动力作用在一侧车轮上,会产生跑偏等问题)
