汽车理论matlab作业.docx

一、确定一轻型货车的动力性能。1）绘制汽车驱动力与行驶阻力平衡图；2）求汽车最高车速与最大爬坡度；3）绘制汽车行驶加速度倒数曲线；用计算机求汽车用Ⅱ档起步加速行驶至70km/h所需的加速时间。已知数据略。（参见汽车理论习题第一章第3题）解题程序如下用Matlab语言1绘制汽车驱动力与行驶阻力平衡图m12000;m21800;mz3880;g9.81;r0.367;CdA2.77;f0.013;nT0.85;ig[5.562.7691.6441.000.793];i05.83;If0.218;Iw11.798;Iw23.598;Iw2*Iw14*Iw2;fori169nii11*50;Ttqi-19.313295.27*ni/1000-165.44*ni/1000240.874*ni/10003-3.8445*ni/10004;endforj15fori169Fti,jTtqi*igj*i0*nT/r;uai,j0.377*r*ni/igj*i0;Fzi,jCdA*uai,j2/21.15mz*g*f;endendplotua,Ft,ua,Ff,ua,FfFwtitle汽车驱动力与行驶阻力平衡图;xlabeluakm/h;ylabelFtN;gtextFt1gtextFt2gtextFt3gtextFt4gtextFt5gtextFfFw2求最大速度和最大爬坡度fork1175n1k3300k*0.1;Ttqk-19.313295.27*n1k/1000-165.44*n1k/1000240.874*n1k/100033.8445*n1k/10004;FtkTtqk*ig5*i0*nT/r;uak0.377*r*n1k/ig5*i0;FzkCdA*uak2/21.15mz*g*f;EkabsFtk-Fzk;endfork1175ifEkminEdisp汽车最高车速;dispuak;dispkm/h;endendforp1150n2p2000p*0.5;Ttqp-19.313295.27*n2p/1000-165.44*n2p/1000240.874*n2p/10003-3.8445*n2p/10004;FtpTtqp*ig1*i0*nT/r;uap0.377*r*n2p/ig1*i0;FzpCdA*uap2/21.15mz*g*f;afpasinFtp-Fzp/mz*g;endforp1150ifafpmaxafitanafp;disp汽车最大爬坡度;dispi;endend汽车最高车速99.0679km/h汽车最大爬坡度0.3518（3）计算2档起步加速到70km/h所需时间fori169nii11*50;Ttqi-19.313295.27*ni/1000-165.44*ni/1000240.874*ni/10003-3.8445*ni/10004;endforj15fori169deta1Iw/mz*r2If*igj2*i02*nT/mz*r2;uai,j0.377*r*ni/igj*i0;ai,jTtqi*igj*i0*nT/r-CdA*uai,j2/21.15-mz*g*f/deta*mz;ifai,j0.05b1i,jai,j;u1i,juai,j;elseb1i,jai-1,j;u1i,juai-1,j;endbi,j1/b1i,j;endendx1u1,1;y1b,1;x2u1,2;y2b,2;x3u1,3;y3b,3;x4u1,4;y4b,4;x5u1,5;y5b,5;plotx1,y1,x2,y2,x3,y3,x4,y4,x5,y5;title加速度倒数时间曲线;axis[0120030];xlabeluakm/h;ylabel1/aj;gtext1/a1gtext1/a2gtext1/a3gtext1/a4gtext1/a5fori169Auai,3-ua69,2;ifA0ji;endBuai,4-ua69,3;ifB0ki;endifuai,40.15;g3izi0.08;endifzi0.3;g3i0.38zi-0.3/0.74;endendz10.150.010.3;g4z1-0.08;plotz,gf1,-.,z,gf2,z,gr1,-.,z,gr2,z,g,z,g3,xk,z1,g4,xaxis[0101.2]title利用附着系数与制动强度的关系曲线xlabel制动强度z/gylabel利用附着系数ggtext空车前轴gtext空车后轴gtext满载前轴gtext满载后轴gtextECE法规C00.051;Er1a1/L./1-betaC*hg1/L*100;EfL-a2/L./beta-C*hg2/L*100;Era2/L./1-betaC*hg2/L*100;plotC,Er,C,Ef,C,Er1axis[010100]title前后附着效率曲线xlabel附着系数Cylabel制动效率（）gtext满载gtextEfgtextErgtext空载gtextErC10.8E1ak1/L./1-betaC1*hg1/L;E2am2/L/1-betaC1*hg2/L;a1E1*C1*9.8;a2E2*C1*9.8;ua30;i210.02;i220.02;s1i21i22/2*ua/3.6ua2/25.92*ak1;s2i21i22/2*ua/3.6ua2/25.92*am2;disp满载时不抱死的制动距离disps2disp空载时不抱死的制动距离disps1