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1、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');xla
2、bel('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=[6.093.091.711.00];ig_5=[5.562.7691.6441.000.793];ua_4=zeros(4,length(n));Ft_4=zeros(4,length(n));ua_5=zer
3、os(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);endforj=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
4、,:),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,:));ti
5、tle('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
6、*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,
7、:),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FtFf+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,:),10
8、00*Ft_5(3,:),ua_5(4,:),1000*Ft_5(4,:),ua
