汽车运用工程大作业.doc

汽车运用工程大作业 汽车动力性计算（加速性能、最高车速、动力因素加速时间和加速距离）已知：发动机外特性、装载质量、整备质量、总质量、车轮半径、传动系效率、滚动阻力系数、空气阻力系数迎风面积、主减速器速比飞轮转动惯量、两个前轮转动惯量、四个后轮转动惯量、变速器速比、轴距、质心至前轴距离、质心高度。例如，已知数据如下表:项目单位数值装载质量kg1995整备质量kg1700总质量kg3695车轮半径m0.37传动系效率0.87滚动阻力系数0.012空气阻力系数迎风面积m22.60主减速器速比5.83飞轮转动惯量kgm20.22两前轮转动惯量kgm21.80四后轮转动惯量kgm23.60轴距m3.40质心至前轴距离m2.0质心高度m0.9变速器速比变速器I档II档III档IV档V档四档6.123.111.691.00五档3.552.771.651.000.83发动机外特性 Tq=a+a1(n/c)+a2(n/c)2+a2(n/c)3+a3(n/c)4 参数aa1a2a2a3c数值-19.31296-16540.9-3.8510001) 绘制汽车驱动力与行驶阻力平衡图；2) 求汽车的最高车速、最大爬坡度；3) 绘制加速度倒数曲线4) 用图解法或编程绘制汽车动力因数特性曲线5) 图解手工绘制II档起步，加速至70km/h的车速时间曲线以及距离时间曲线。1、绘制汽车驱动利于行驶阻力平衡图m1=1995;m2=1700;mz=3695;g=9.81;f=0.0125-0.0025; nt=0.87+0.025;cda=2.60;r=0.37;n=600:1:4600;i0=5.83;ig1=6.12;ig2=3.11;ig3=1.69;ig4=1.00;ua1=0.377*r.*n/(ig1.*i0);ua2=0.377*r.*n/(ig2.*i0);ua3=0.377*r.*n/(ig3.*i0);ua4=0.377*r.*n/(ig4.*i0);a=-19.31;a1=296;a2=-165;a3=40.9;a4=-3.85;c=1000;tq=a+a1*(n/c)+a2*(n/c).2+a3*(n/c).3+a4*(n/c).4;ft1=tq.*ig1.*i0.*nt/r;ft2=tq.*ig2.*i0.*nt/r;ft3=tq.*ig3.*i0.*nt/r;ft4=tq.*ig4.*i0.*nt/r;fz1=mz.*g.*f+cda*ua1.2/21.15; %fz=Ff+Fwfz2=mz.*g.*f+cda*ua2.2/21.15;fz3=mz.*g.*f+cda*ua3.2/21.15;fz4=mz.*g.*f+cda*ua4.2/21.15;plot(ua1,ft1,ua2,ft2,ua3,ft3,ua4,ft4,ua1,fz1,ua2,fz2,ua3,fz3,ua4,fz4);title(驱动力与行驶阻力平衡图);Xlabel(ua(km/h);Ylabel(ft(N); gtext(Ft1) gtext(Ft2) gtext(Ft3) gtext(Ft4) gtext(Ff+Fw)2、求汽车的最高车速、最大爬坡度1）汽车的最高车速当Ft=Ff+Fw时,汽车处于稳定状态,并达到最高车速 用matlab对驱动力与行驶阻力图进行放大处理可得交点坐标为（106.53，1757.68）因此，uamax=106.53km/h2）最大爬坡度一档时有最大爬坡度, 用matlab对驱动力与行驶阻力图进行放大处理可得当ua=8.56km/h时，Ft1-(Ff+Fw)最大值。m1=1995;m2=1700;mz=3695;g=9.81;f=0.0125-0.0025; nt=0.87+0.025;cda=2.60;r=0.37;i0=5.83;ig1=6.12;ig2=3.11;ig3=1.69;ig4=1.00;ua1=8.56;n=ua1.*ig1.*i0/(0.377.*r);a=-19.31;a1=296;a2=-165;a3=40.9;a4=-3.85;c=1000;tq=a+a1*(n/c)+a2*(n/c).2+a3*(n/c).3+a4*(n/c).4;ft1=tq.*ig1.*i0.*nt/rfz1=mz.*g.*f+cda*ua1.2/21.15 %fz=Ff+Fw输出：ft1 =15415Nfz1 =371.4871Ni=tan=tanarcsin(ft1-fz1)/(mz.*g)可知： =24.02.i=tan=0.443、绘制加速度倒数曲线n=600:1:4000;r=0.37;nt=0.87+0.025;f=0.0125-0.0025;m=3695;g=9.81;G=m.*g;CDA=2.60;If=0.22;Iw1=1.80;Iw2=3.60;i0=5.83;ig1=6.12;ig2=3.11;ig3=1.69;ig4=1.00;ua1=0.377*r.*n/(ig1.*i0);ua2=0.377*r.*n/(ig2.*i0);ua3=0.377*r.*n/(ig3.*i0);ua4=0.377*r.*n/(ig4.*i0);a=-19.31;a1=296;a2=-165;a3=40.9;a4=-3.85;c=1000;tq=a+a1*(n/c)+a2*(n/c).2+a3*(n/c).3+a4*(n/c).4;b1=1+(Iw1+Iw2)./(m.*r.2)+(If.*ig1.2.*i0.2.*nt)/(m.*r.2);b2=1+(Iw1+Iw2)./(m.*r.2)+(If.*ig2.2.*i0.2.*nt)/(m.*r.2);b3=1+(Iw1+Iw2)./(m.*r.2)+(If.*ig3.2.*i0.2.*nt)/(m.*r.2);b4=1+(Iw1+Iw2)./(m.*r.2)+(If.*ig4.2.*i0.2.*nt)/(m.*r.2);ft1=tq.*ig1.*i0.*nt/r;ft2=tq.*ig2.*i0.*nt/r;ft3=tq.*ig3.*i0.*nt/r;ft4=tq.*ig4.*i0.*nt/r;fw1=CDA.*(ua1.2)/21.15;fw2=CDA.*(ua2.2)/21.15;fw3=CDA.*(ua3.2)/21.15;fw4=CDA.*(ua4.2)/21.15;D1=(ft1-fw1)./G;D2=(ft2-fw2)./G;D3=(ft3-fw3)./G;D4=(ft4-fw4)./G;a1=g.*(D1-f)/b1;a2=g.*(D2-f)/b2;a3=g.*(D3-f)/b3;a4=g.*(D4-f)/b4;plot(ua1,1./a1,ua2,1./a2,ua3,1./a3,ua4,1./a4);title(加速度倒数曲线图);Xlabel(ua(km/h);Ylabel(1/a(m/s2);gtext(1/a1) gtext(1/a2) gtext(1/a3) gtext(1/a4) 4、用图解法或编程绘制汽车动力因数特性曲线n=600:1:4000;r=0.37;nt=0.87+0.025;f=0.0125-0.0025;m=3695;g=9.81;G=m.*g;CDA=2.60;If=0.22;Iw1=1.80;Iw2=3.60;i0=5.83;ig1=6.12;ig2=3.11;ig3=1.69;ig4=1.00;ua1=0.377*r.*n/(ig1.*i0);ua2=0.377*r.*n/(ig2.*i0);ua3=0.377*r.*n/(ig3.*i0);ua4=0.377*r.*n/(ig4.*i0);a=-19.31;a1=296;a2=-165;a3=40.9;a4=-3.85;c=1000;tq=a+a1*(n/c)+a2*(n/c).2+a3*(n/c).3+a4*(n/c).4;b1=1+(Iw1+Iw2)./(m.*r.2)+(If.*ig1.2.*i0.2.*nt)/(m.*r.2);b2=1+(Iw1+Iw2)./(m.*r.2)+(If.*ig2.2.*i0.2.*nt)/(m.*r.2);b3=1+(Iw1+Iw2)./(m.*r.2)+(If.*ig3.2.*i0.2.*nt)/(m.*r.2);b4=1+(Iw1+Iw2)./(m.*r.2)+(If.*ig4.2.*i0.2.*nt)/(m.*r.2);ft1=tq.*ig1.*i0.*nt/r;ft2=tq.*ig2.*i0.*nt/r;ft3=tq.*ig3.*i0.*nt/r;ft4=tq.*ig4.*i0.*nt/r;fw1=CDA.*(ua1.2)/21.15;fw2=CDA.*(ua2.2)/21.15;fw3=CDA.*(ua3.2)/21.15;fw4=CDA.*(ua4.2)/21.15;D1=(ft1-fw1)./G;D2=(ft2-fw2)./G;D3=(ft3-fw3)./G;D4=(ft4-fw4)./G;plot(ua1,D1,ua2,D2,ua3,D3,ua4,D4)title(汽车动力特性图);Xlabel(ua(km/h);Ylabel(D);gtext() gtext() gtext() gtext()5、图解手工绘制档起步，加速至70km/h的车速时间曲线以及距离-时间曲线m=3695;g=9.8; G=m*g;nmin=600;nmax=4500;ig=6.12 3.11 1.69 1.00; i0=5.83;nt=0.87+0.025;f=0.012-0.0025;r=0.37;cda=2.60;If=0.22;Iw1=1.80;Iw2=3.60;u1=0.377*r*nmin./ig/i0;u2=0.377*r*nmax./ig/i0;deta=0*ig;for i=1:4 deta(i)=1+(Iw1+Iw2)/(m*r2)+(If*(ig(i)2*i02*nt)/(m*r2);endua=6:0.01:99;N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;Ff=G*f;Fw=cda*ua.2/21.15;for i=1:N k=i; if ua(i)=u2(2) n=ua(i)*(ig(2)*i0/r)/0.377; Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)2+40.874*(n/1000)3-3.8445*(n/1000)4; Ft=Tq*ig(2)*i0*nt/r; inv_a(i)=(deta(2)*m)/(Ft-Ff-Fw(i); delta(i)=0.01*inv_a(i)/3.6; elseif ua(i)=u2(3) n=ua(i)*(ig(3)*i0/r)/0.377; Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)2+40.874*(n/1000)3-3.8445*(n/1000)4; Ft=Tq*ig(3)*i0*nt/r; inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i); delta(i)=0.01*inv_a(i)/3.6; else n=ua(i)*(ig(4)*i0/r)/0.377; Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)2+40.874*(n/1000)3-3.8445*(n/1000)4; Ft=Tq*ig(4)*i0*nt/r; inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i); delta(i)=0.01*inv_a(i)/3.6; end a=delta(1:k); t(i)=sum(a);endplot(t,ua);axis(0 30 0 80);title(汽车档起步加速至70km/h的车速-时间曲线);xlabel(时间t（s）);ylabel(速度ua（km/h);zoom onx,y=ginput(1);zoom off;disp(汽车档起步加速至70km/h的加速时间);disp(x);disp(s);汽车档起步加速至70km/h的加速时间t=20.0115s 汽车燃料经济性计算（等速、多工况）例如，已知汽车结构参数同题1，负荷特性拟合公式为N/(rmin-1) B0B1B2B3B48201427-41672-6.00.1812001355-30437-2.050.04316001284-19015-0.510.00720001123-121.67.0-0.1850.001926001141-994.5-0.0910.000730001051-742.86-0.0510.0003534001233-853.0-0.04750.000338801130-450.71-0.0008-0.00004怠速油耗为0.3ml/s（400r/min），求1) 汽车功率平衡图；2) 最高档与次高档的等速百公里油耗曲线。3) 按6工况循环行驶的百公里油耗。计算中确定燃油消耗率值b时，若发动机转速与负荷特性中给定的转速不相等，可根据相邻转速的两根曲线用插值法求得。1、汽车功率平衡图m=3695;g=9.8;r=0.37; nt=0.87+0.025;f=0.0125-0.0025; cda=2.60;If=0.22;Iw1=1.80;Iw2=3.60;i0=5.83;ig=6.12 3.11 1.69 1.00;for i=1:79n(i)=(i+11)*50;a=-19.31;a1=296;a2=-165;a3=40.9;a4=-3.85;c=1000;Tq(i)=a+a1*(n(i)/c)+a2*(n(i)/c).2+a3*(n(i)/c).3+a4*(n(i)/c).4; endfor j=1:4for i=1:79ua(i,j)=0.377.*r.*n(i)/(ig(j).*i0);Pe(i,j)=Tq(i).*ig(j).*i0.*nt.*ua(i,j)/(3600.*r);Pfw(i,j)=(m.*g.*f.*ua(i,j)/3600+cda.*ua(i,j).3/76140)/nt;endendplot(ua,Pe,ua,Pfw)title(功率平衡图);xlabel(ua(km/h); ylabel(Pe,Pfw(kw);gtext() gtext() gtext() gtext() gtext(Pf+Pw)/t)2、最高档与次高档的等速百公里油耗曲线1）最高档等速百公里油耗曲线r=0.37;nt =0.87+0.025; f=0.0125-0.0025;m=3695;g=9.81;G=m.*g;cda=2.60;pg=7.12;i0=5.83; ig3=1.69;ig4=1; n=800 1200 1600 2000 2600 3000 3400 3800;B0=1427 1355 1284 1123 1141 1051 1233 1130;B1=-416 -304 -190 -121.6 -99 -74 -85 -45 ;B2=72 37 15 7.0 4.5 2.86 3.0 0.71;B3=-6.0 -2.05 -0.51 -0.185 -0.091 -0.051 -0.0475 -0.0008;B4=0.18 0.043 0.007 0.0019 0.0007 0.00035 0.0003 -0.00004;ua=(0.377*r*n)/(ig4*i0);a=-19.31;a1=296;a2=-165;a3=40.9;a4=-3.85;c=1000;tq=a+a1*(n/c)+a2*(n/c).2+a3*(n/c).3+a4*(n/c).4;P=(1/nt)*(G*f*ua/3600+cda*ua.3/76140);b=B0+B1.*P+B2.*P.2+B3.*P.3+B4.*P.4;Qs=P.*b./(1.02*ua*pg);b=polyfit(ua,Qs,3);ua4=8:1:100;f=polyval(b,ua4);figure;plot(ua,Qs,k.,ua4,f,LineWidth,2);title(汽车最高档等速百公里油耗曲线);xlabel(ua/(km/h);ylabel(Qs/1/L(100km);2）次高档等速百公里油耗曲线r=0.37;nt =0.87+0.025; f=0.0125-0.0025;m=3695;g=9.81;G=m.*g;cda=2.60;pg=7.12;i0=5.83; ig3=1.69;ig4=1; n=800 1200 1600 2000 2400 2800 3200 3600; B0=1427 1355 1284 1123 1141 1051 1233 1130;B1=-416 -304 -190 -121.6 -99 -74 -85 -45 ;B2=72 37 15 7.0 4.5 2.86 3.0 0.71;B3=-6.0 -2.05 -0.51 -0.185 -0.091 -0.051 -0.0475 -0.0008;B4=0.18 0.043 0.007 0.0019 0.0007 0.00035 0.0003 -0.00004;ua=(0.377*r*n)/(ig3*i0);a=-19.31;a1=296;a2=-165;a3=40.9;a4=-3.85;c=1000;tq=a+a1*(n/c)+a2*(n/c).2+a3*(n/c).3+a4*(n/c).4;P=(1/nt)*(G*f*ua/3600+cda*ua.3/76140);b=B0+B1.*P+B2.*P.2+B3.*P.3+B4.*P.4;Qs=P.*b./(1.02*ua*pg);b=polyfit(ua,Qs,3);ua3=8:1:55;f=polyval(b,ua3);figure;plot(ua,Qs,k.,ua3,f,LineWidth,2);title(汽车次高档等速百公里油耗曲线);xlabel(ua/(km/h);ylabel(Qs/1/L(100km);3、按6工况循环形式的百公里耗油clear;m=3695; g=9.81; G=m*g;pg=7.00;Iw1=1.80;Iw2=3.60;Iw=Iw1+Iw2;If=0.22;f=0.0125-0.0025; nt=0.87+0.025; cda=2.60; r=0.37;i0=5.83;ig=3.55 2.77 1.65 1.00 0.83;a=-19.31;a1=296;a2=-165;a3=40.9;a4=-3.85;c=1000;for i=1:137,n(i)=(i+23)*25;endfor i=1:137,Tq(i)=a+a1*(n(i)/c)+a2*(n(i)/c).2+a3*(n(i)/c).3+a4*(n(i)/c).4;endfor j=1:5 for i=1:137 ua(i,j)=0.377*r*n(i)/ig(j)/i0;Pz(i,j)=(G*f*ua(i,j)/3600+cda*ua(i,j)3/76140)/nt;endendn0=815 1207 1614 2012 2603 3006 3403 3804;B0=1427 1355 1284 1123 1141 1051 1233 1130;B1=-416 -304 -190 -121.6 -99 -74 -85 -45 ;B2=72 37 15 7.0 4.5 2.86 3.0 0.71;B3=-6.0 -2.05 -0.51 -0.185 -0.091 -0.051 -0.0475 -0.0008;B4=0.18 0.043 0.007 0.0019 0.0007 0.00035 0.0003 -0.00004;for j=1:5for i=1:8Tq(i)=a+a1*(n0(i)/c)+a2*(n0(i)/c).2+a3*(n0(i)/c).3+a4*(n0(i)/c).4;ub(i,j)=0.377*r*n0(i)/ig(j)/i0;Peb(i)=Tq(i)*n0(i)/9549;b(i)=B0(i)+B1(i)*Peb(i)+B2(i)*Peb(i)2+B3(i)*Peb(i)3+B4(i)*Peb(i)4;endendub1=ub(:,1);ub2=ub(:,2);ub3=ub(:,3);ub4=ub(:,4);ub5=ub(:,5);b1=polyfit(ub1,b,3);b2=polyfit(ub2,b,3);b3=polyfit(ub3,b,3);b4=polyfit(ub4,b,3);b5=polyfit(ub5,b,3);for k=1:137bh(k,1)=polyval(b1,ua(k,1);bh(k,2)=polyval(b2,ua(k,2);bh(k,3)=polyval(b3,ua(k,3);bh(k,4)=polyval(b4,ua(k,4);bh(k,5)=polyval(b5,ua(k,5);endfor i=1:5for k=1:137Q(k,i)=Pz(k,i)*bh(k,i)/(1.02*ua(k,i)*pg); endendua(1)=40;P1=(G*f* ua(1)/3600+cda*ua(1)3/76140)/nt;ba1=interp1(ub4,b,ua(1);Q1=P1*125*ba1/(102*ua(1)*pg); a=1+Iw/(m*r2)+If*ig(3)2*i02*nt/(m*r2); Q2=0;t1=1/(0.2*3.6);for i=1:10 u2(1)=ua(1); u2(i+1)=u2(i)+ 1; P2(i)=(G*f* u2(i)/36