汽车主减速器传动比优化

1、汽车主减速器传动比优化某轻型货车，车有关数据如下：发动机的最低转速nmin=600r/min,最高转速nmax=4000r/min。总质量3650kg;车轮半径0.367m;传动系机械效率nT=0.85;滚动阻力系数f=0.013;空气阻力系数*迎风面积CDAf2.77m2;飞轮转动惯量If=0.218kg.m2;二前轮转动惯量Iw1=1.798kg.m2;轴距L=3.2m;质心至前轴距离（满载）a=1.947m;质心高（满载）hg=0.9m;四后轮转动惯量Iw2=3.598kg.m2;T=-19.313+295.27*（n/1000）-165.44*（门/1000）八2+40.874*（0/

2、1000）八3-3.8445*(n/1000)a4;怠速油耗Qid=0.299mL/s(怠速转速400r/min)负荷特性曲线拟合公式为:b=B0+B1*Pe+B2*Pe.A2+B3*Pe.A3+B4*Pe.A4.N/(r/min)B0B1B2B3B4815:1326.8-416.4672.379-5.86290.1776812071354.7-303.9836.657-2.0553:0.04307216141284.4-189.751452.4-0.511840.006816420121122.9-121.597.0035-0.185170.001855526031141.0-98.8934

3、.4763-0.0910770.000689063006:1051.2-73.7142.8593-0.05138:0.0003503234031233.9-84.4782.9788-0.0474490.0002823038041129.7-45.2910.71113-0.00075215-0.0000385681档2档3档.4档5档变速器传动比5.064.0163.091.711计算1 计算加速时间Matlab程序：n=600:1:4000;m=3650;g=9.8;G=m*g;r=0.367;i0=5.089;nT=0.85;f=0.013;CdA=2.77;Iw1=1.798;Iw2=3.

4、598;Iw=Iw1+Iw2;If=0.218;a=1.947;hg=0.9;L=3.2;Ttq=-19.313+295.27*n/1000-165.44*(门/1000)八2+40.874*(门/1000)八3-3.8445*(n/1000).A4;%以2挡加速时间计算u(1)=0.377*r*600/i0/4.016;dt=0.01;w=1;t(1)=0;ig=4.016;while(u(w)<99.08)n(w)=u(w)*ig*i0/0.377/r;Ttq(w)=-19.313+295.27*n(w)/1000-165.44*(n(w)/1000)A2+40.874*(n(w)/

5、1000)A3-3.8445*(n(w)/1000)A4;Ft(w)=Ttq(w)*ig*i0*nT/r;Ff=G*f;Fw(w)=CdA*u(w)A2/21.15;q=1+Iw/(m*rA2)+If*igA2*i0A2*nT/(m*rA2);a(w)=3.6*(Ft(w)-(Ff+Fw(w)/q/m;u(w+1)=u(w)+a(w)*dt;if(u(w+1)>=0.377*4000*r/4.016/i0)ig=3.09;endif(u(w+1)>=0.377*4000*r/3.09/i0)ig=1.71;endif(u(w+1)>=0.377*4000*r/1.71/i0)

6、ig=1;endt(w+1)=(w+1)*dt;w=w+1;endfigure;plot(t,u);axis(0800100);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);以加速到70公里的时间作为加速时间。口X60Fgure1文件旧喘辑查看凶插入田二桌面他岂口帮助凹2 0每头?硬尿T层10090io5.0895.445.856.016.17加速时间24.055324

7、.239624.055323.871023.68662计算六工况百公里油耗%等速百公里油耗n=600:1:4000;m=3650;g=9.8;G=m*g;r=0.367;i0=5.089;nT=0.85;f=0.013;CdA=2.77;n仁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,-45.291Jb2=72.379,36.6

8、57,14.524,7.0035,4.4763,2.8593,2.9788,0.71113;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=spline(n1,b

9、4,n);pg=7;ig=1.00;Ua=0.377*r*n/ig/i0;Pf=G*f*Ua/3600;Pw=CdA*Ua.A3/76140;P=(Pf+Pw)/nT;b=B0+B1.*P+B2.*P.A2+B3.*P.A3+B4.*P.A4;Q=P.*b./(1.02*Ua*pg);Iw1=1.798;Iw2=3.598;Iw=Iw1+Iw2;If=0.218;pg=7;Ff=G*f;ua1=25,40,50;Fw=CdA*ua1.A2/21.15;Pa=(Ff+Fw).*ua1/3600/nT;b=spline(P,b,Pa);s=50,250,250;Q1=s.*Pa.*b./(102*

10、ua1*pg);disp(Q1);Q1=Q1(1)+Q1(2)+Q1(3);%匀加速行驶的油耗%第一段ua=25:1:40;a=0.25;q=1+Iw/(m*rA2)+If*igA2*i0A2*nT/(m*rA2);Pa=(G*f*ua/3600+CdA*ua.A3/76140+q*m*ua.*a/3600)/nT;n=ua*ig*i0/0.377/r;B0=spline(n1,b0,n);B1=spline(n1,b1,n);B2=spline(n1,b2,n);B3=spline(n1,b3,n);B4=spline(n1,b4,n);b=B0+B1.*Pa+B2.*Pa.A2+B3.*P

11、a.A3+B4.*Pa.A4;b=spline(Pa,b,Pa);Qs=Pa.*b/(367.1*pg);t=1/(3.6*a);Q21=0;forn=1:15Q21=Q21+(Qs(n)+Qs(n+1)*t/2;enddisp(Q21);%第二段ua=40:1:50;a=0.20;q=1+Iw/(m*rA2)+If*igA2*i0A2*nT/(m*rA2);Pa=(G*f*ua/3600+CdA*ua43/76140+q*m*ua.*a/3600)/nT;n=ua*ig*i0/0.377/r;B0=spline(n1,b0,n);B仁spline(n1,b1,n);B2=spline(n1,

12、b2,n);B3=spline(n1,b3,n);B4=spline(n1,b4,n);b=B0+B1.*Pa+B2.*Pa.A2+B3.*Pa.A3+B4.*Pa.A4;b=spline(Pa,b,Pa);Qs=Pa.*b/(367.1*pg);t=1/(3.6*a);Q22=0;Q22=Q22+(Qs(n)+Qs(n+1)*t/2;enddisp(Q22);Q2=Q21+Q22;%匀减速行驶的油耗Qid=0.299;t3=19.3;Q3=Qid*t3;disp(Q3);%总油耗s=1075;Q=(Q1+Q2+Q3)*100/1075;disp(Q)；io5.0895.445.856.016

13、.17Q(L)13.000613.408613.739913.853513.96823.绘制燃油经济性-加速时间曲线Q=13.000613.408613.739913.853513.9682;t=24.055324.239624.055323.871023.6866;plot(Q,t,'+r');holdonq1=linspace(Q,Q(5),100);t1=spline(Q,t,q1);%三次样条插值plot(q1,t1);%绘制燃油经济性-加速时间曲线title(燃油经济性一加速时间曲线);xlabel('百公里油耗/(L/100km)');ylabel(

14、'加速时间/s');gtext('i0=5.089'),gtext('i0=5.44'),gtext('i0=5.85'),gtext('i0=6.01'),gtext('i0=6.17');Figure1文件（D桶CE童看凹MAQ）工宾CD奠面助窗口应帮助凹|傀食凸口尿|口匡1|口该油经济性一加速时I国无酝23023723 5-JIIIIII13.313413513.613.713813514百公里油AKL7100km)4.计算最昌车速n=600:1:4000;r=0.367;i0=5.089;n

15、T=0.85;f=0.013;m=3650;g=9.8;G=m*g;CdA=2.77;a=1.947;hg=0.9;L=3.2;If=0.218;Ttq=-19.313+295.27*n/1000-165.44*(门/1000)八2+40.874*(门/1000)八3-3.8445*(n/1000).A4;呜区动力行驶阻力平衡图forig=5.06,4.016,3.09,1.71,1Ua=0.377*r*n/ig/i0;Ft=Ttq*ig*i0*nT/r;plot(Ua,Ft);holdon;endFf=G*f;ua=0:0.1:max(Ua);Fw=CdA*ua.A2/21.15;plot(

16、ua,(Ff+Fw);title('驱动力-行驶阻力平衡图');xlabel('Ua/(km/h)');ylabel('Ft/N');i05.0895.4465.856.016.17umax102.4102.1100.299.297.95.绘制iO-umax曲线(求最高车速约束条件下临界iO值)i0=5.089 5.44 5.85 6.01 6.17;umax=102.4 102.1 100.2 99.2 97.9;plot(i0,umax,'+r');hold oni01=li nspace(i0,i0 (5);umax1=sp

17、li ne(i0,umax,i01);plot(i01,umax1);title('i0-umax 曲线')；xlabel('i0');ylabel('最高车速 km/h');x,y=gi nput(1);disp('临界i0=');disp(x);%根据最高车速约束条件，求临界i0值gtext('i0=5.089'),gtext('i0=5.44'),gtext('i0=5.85'), gtext('i0=6.01'),gtext('i0=6.17'

18、);立件CD褊揖 卷看凹 插入CD TMCD至面窗口他 帮H力凹甥遽”？忌 口用 回102 5102lO-urnax 曲101.5101100.610059 55933 5S857 5'5J52山6.453j0=5 85J0-G.01fl临界i0=5.8855JL6I52所以io取5.0895.445.85iO6.绘制iO-t图(求加速时间约束下临界i0值)i0=5.0895.445.856.016.17;t=24.055324.239624.055323.871025.6866;plot(i0,t,'+r');holdon;i01=linspace(i0,i0(5);

19、umax仁spline(i0,t,i01);plot(i01,umax1);title('i0-t曲线')；xlabel('i0');ylabel('力口速时间s);zoomon;x,y=ginput(1);zoomoff;disp('临界i0=');disp(x);gtext('i0=5.089'),gtext('i0=5.44'),gtext('i0=5.85'),gtext('i0=6.01'),gtext('i0=6.17');Figure1文件(E桶

20、I日SW(y)插人工具CD桌血0WQfiDWED(HlEEffi口已IB|fe%2/E"Q口(丁|itH曲线加速时间不超过25s所以io可以取5.0895.445.856.01匚4.27最大爬坡度计算n=600:1:4000;r=0.367;i0=5.089;eff=0.85;f=0.013;m=3650;g=9.8;G=m*g;CdA=2.77;a=1.947;hg=0.9;L=3.2;lf=0.218;Ttq=-19.313+295.27*n/1000-165.44*(门/1000)八2+40.874*(门/1000)八3-3.8445*(n/1000).A4;ig=5.064.

21、0163.091.711;Ft仁Ttq*ig(1)*i0*nT/r;ua1=0.377*r*n/ig(1)/i0;Ff=G*f;Fw1=CdA*ua1.A2/21.15;Fz1=Ff+Fw1;Fi1=Ft1-Fz1;imax=100*tan(asin(max(Fi1/G);disp('汽车最大爬坡度=');disp(imax);disp(%);i05.0895.445.856.016.17i(%)28.973131.274134.013335.101736.2011绘制i0-i曲线（求最大爬坡度约束下i0）i0=5.0895.445.856.016.17;i=28.973131

22、.274134.013335.101736.2011;plot(i0,i,'+r');holdoni01=linspace(i0,i0(5),100);i1=spline(i0,i,i01);plot(i01,i1);title('i0-imax曲线')；xlabel('i0');ylabel('imax(%)');x,y=ginput(1);disp(临界i0=');disp(x);gtext('i0=5.089'),gtext('i0=5.44'),gtext('i0=5.85'),gtext('i0=6.01'),gtext('i0=6.17');373G3534FlFigure1文件（B扁辑（D查看M搔人工具CD莞面（B窗口呦mtH）iOGmax曲线#0=617Jr4=601MW851032最大的爬坡度大于32%因此io大于5.55,io可取5.856.016.17