汽车理论大作业 同济大学汽车学院xxxxxxxxx %0. 作业要求%1. 发动机外特性曲线nmin=600;nmax=4000;n=nmin:0.01:nmax;m=n/1000;Tq=-19.313+295.27*m-165.44*m.2+40.874*m.3-3.8445*m.4;figure;plot(n,Tq);title(发动机外特性曲线 Tq-n);xlabel(n/(r/min);ylabel(Tq/Nm);Pe=(Tq.*n)/9550;figure;plot(n,Pe);title(发动机外特性曲线 Pe-n);xlabel(n/(r/min);ylabel(Pe/kw);%2.驱动力曲线nmin=600;nmax=4000;n=nmin:0.01:nmax;m=n/1000;Tq=-19.313+295.27*m-165.44*m.2+40.874*m.3-3.8445*m.4;r=0.367;elta=0.85;i0=5.83;ig_4=6.09 3.09 1.71 1.00;ig_5=5.56 2.769 1.644 1.00 0.793;ua_4=zeros(4,length(n);Ft_4=zeros(4,length(n);ua_5=zeros(5,length(n);Ft_5=zeros(5,length(n);fori=1:4ua_4(i,:)=(0.377*n.*r)/(i0*ig_4(i);Ft_4(i,:)=Tq*ig_4(i)*i0*elta/(r*1000);endfor j=1:5ua_5(j,:)=(0.377*n.*r)/(i0*ig_5(j);Ft_5(j,:)=Tq*ig_5(j)*i0*elta/(r*1000);end%figure;plot(ua_4(1,:),Ft_4(1,:),ua_4(2,:),Ft_4(2,:),ua_4(3,:),Ft_4(3,:),ua_4(4,:),Ft_4(4,:);title(4档变速箱驱动力曲线 Ft-ua);xlabel(ua/(km/h);ylabel(Ft/kN);text(15.5,14,Ft1);text(22,7.7,Ft2);text(35,4.5,Ft3);text(75,2.7,Ft4);%figure;plot(ua_5(1,:),Ft_5(1,:),ua_5(2,:),Ft_5(2,:),ua_5(3,:),Ft_5(3,:),ua_5(4,:),Ft_5(4,:),ua_5(5,:),Ft_5(5,:);title(5档变速箱驱动力曲线 Ft-ua);xlabel(ua/(km/h);ylabel(Ft/kN);text(16,13,Ft1);text(20,7,Ft2);text(35,4.5,Ft3);text(75,2.8,Ft4); text(105,2.2,Ft5);%3. 计算空载和满载时最高车速m0=1800;m1=3880;f=0.013;Cd=0.68;A=4.07;g=9.8;Ff_0=m0*g*f;Ff_1=m1*g*f;ua4m=0.377*r*nmax/(i0*ig_4(4);ua5m=0.377*r*nmax/(i0*ig_5(5);ua4=0:0.01:ua4m;ua5=0:0.01:ua5m;Fw_4=(Cd*A*(ua4.2)/21.15;Fw_5=(Cd*A*(ua5.2)/21.15;Fz4_0=Ff_0+Fw_4;Fz4_1=Ff_1+Fw_4;Fz5_0=Ff_0+Fw_5;Fz5_1=Ff_1+Fw_5;%figure;plot(ua_4(1,:),1000*Ft_4(1,:),ua_4(2,:),1000*Ft_4(2,:),ua_4(3,:),1000*Ft_4(3,:),ua_4(4,:),1000*Ft_4(4,:),ua4,Fz4_0,ua4,Fz4_1);title(4档变速汽车空载&满载驱动力行驶阻力平衡图 Ft Ff+Fw-ua);xlabel(ua/(km/h);ylabel(F/N);text(15.5,14000,Ft1);text(22,7700,Ft2);text(35,4500,Ft3);text(75,2700,Ft4);text(68,1650,Ff+Fw);%figure;plot(ua_5(1,:),1000*Ft_5(1,:),ua_5(2,:),1000*Ft_5(2,:),ua_5(3,:),1000*Ft_5(3,:),ua_5(4,:),1000*Ft_5(4,:),ua_5(5,:),1000*Ft_5(5,:),ua5,Fz5_0,ua5,Fz5_1);title(5档变速汽车空载&满载驱动力行驶阻力平衡图 Ft Ff+Fw-ua);xlabel(ua/(km/h);ylabel(Ft/N);text(16,13000,Ft1);text(20,7000,Ft2);text(35,4300,Ft3);text(75,2800,Ft4);text(113,1100,Ft5);text(108,2800,Ff+Fw); 由驱动力行驶阻力平衡图得出：4档空载&满载最高车速为 94.93km/h5档空载最高车速为 107km/h 满载为99.12km/h%4. 计算最高车速时的附着率hg_0=0.7;hg_1=0.9;a_0=0.3;b_0=0.7;a_1=0.6;b_1=0.4;L=3.2;ua4_max=94.93;Cfig_4_0=(m0*g*b_0/L)*f+Cd*A*ua4_max2/21.15)/(m0*g*a_0/L);Cfig_4_1=(m1*g*b_1/L)*f+Cd*A*ua4_max2/21.15)/(m1*g*a_1/L);ua5_max0=107.00;ua5_max1=99.12;Cfig_5_0=(m0*g*b_0/L)*f+Cd*A*ua5_max02/21.15)/(m0*g*a_0/L);Cfig_5_1=(m1*g*b_1/L)*f+Cd*A*ua5_max12/21.15)/(m1*g*a_1/L);通过计算得出最高车速时的附着率：4档空载附着率 0.74344档满载附着率0.17415档空载附着率0.93635档满载附着率0.1890%5. 计算空载和满载时最大爬坡度D4_0=zeros(4,length(n);D4_1=zeros(4,length(n);D5_0=zeros(5,length(n);D5_1=zeros(5,length(n);for m=1:4D4_0(m,:)=(1000*Ft_4(m,:)-(Cd*A*(ua_4(m,:).2)/21.15)/(m0*g);D4_1(m,:)=(1000*Ft_4(m,:)-(Cd*A*(ua_4(m,:).2)/21.15)/(m1*g);endfor m=1:5D5_0(m,:)=(1000*Ft_5(m,:)-(Cd*A*(ua_5(m,:).2)/21.15)/(m0*g);D5_1(m,:)=(1000*Ft_5(m,:)-(Cd*A*(ua_5(m,:).2)/21.15)/(m1*g);endi_4_0=zeros(4,length(n);i_4_1=zeros(4,length(n);i_5_0=zeros(5,length(n);i_5_1=zeros(5,length(n);for k=1:4i_4_0(k,:)=100*tan(asin(D4_0(k,:)-f*sqrt(1-D4_0(k,:).2+f*f)/(1+f*f);i_4_1(k,:)=100*tan(asin(D4_1(k,:)-f*sqrt(1-D4_1(k,:).2+f*f)/(1+f*f);endfor k=1:5i_5_0(k,:)=100*tan(asin(D5_0(k,:)-f*sqrt(1-D5_0(k,:).2+f*f)/(1+f*f);i_5_1(k,:)=100*tan(asin(D5_1(k,:)-f*sqrt(1-D5_1(k,:).2+f*f)/(1+f*f);endimax1=max(i_4_0(1,:);uai1=ua_4(1,(find(i_4_0(1,:)=imax1);%figure;plot(ua_4(1,:),i_4_0(1,:),ua_4(2,:),i_4_0(2,:),ua_4(3,:),i_4_0(3,:),ua_4(4,:),i_4_0(4,:);title(4档变速汽车空载爬坡度图i-ua);xlabel(ua/(km/h);ylabel(i/(%);text(15,110,);text(20,47,);text(35,25,);text(75,12,);imax2=max(i_4_1(1,:);uai2=ua_4(1,(find(i_4_1(1,:)=imax2);%figure;plot(ua_4(1,:),i_4_1(1,:),ua_4(2,:),i_4_1(2,:),ua_4(3,:),i_4_1(3,:),ua_4(4,:),i_4_1(4,:);title(4档变速汽车满载爬坡度图i-ua);xlabel(ua/(km/h);ylabel(i/(%);text(17,33,);text(20,19,);text(40,10,);text(80,4,);imax3=max(i_5_0(1,:);uai3=ua_5(1,(find(i_5_0(1,:)=imax3);%figure;plot(ua_5(1,:),i_5_0(1,:),ua_5(2,:),i_5_0(2,:),ua_5(3,:),i_5_0(3,:),ua_5(4,:),i_5_0(4,:),ua_5(5,:),i_5_0(5,:);title(5档变速汽车空载爬坡度图i-ua);xlabel(ua/(km/h);ylabel(i/(%);text(17,90,);text(20,42,);text(35,25,);text(75,12,);text(110,1,);