汽車?yán)碚撟鳂I(yè)-Matlab程序-輕型貨車動(dòng)力性能評價(jià)

輕型貨車動(dòng)力學(xué)性能評價(jià)4209XX班 姓名：XX 學(xué)號：XXXXXXXX已知條件該輕型貨車相關(guān)參數(shù)如下：裝載質(zhì)量2000kg整車裝備質(zhì)量1800kg總質(zhì)量（總重G）3800kg（38062.8N）車輪半徑（r）0.367m傳動(dòng)系機(jī)械效率η滾動(dòng)阻力系數(shù)f=0.013空氣阻力系數(shù)X迎風(fēng)面積C主減速器傳動(dòng)比i飛輪轉(zhuǎn)動(dòng)慣量I二前輪轉(zhuǎn)動(dòng)慣量I四后輪轉(zhuǎn)動(dòng)慣量I軸距L=3.2m質(zhì)心至前軸的距離（滿載）a=1.947m質(zhì)心高h(yuǎn)變速器傳動(dòng)比ig變速器傳動(dòng)比數(shù)據(jù)如下：擋位1擋2擋3擋4擋5擋傳動(dòng)比i5.562.7691.6441.000.793發(fā)動(dòng)機(jī)最低轉(zhuǎn)速為n=600r/min，最高轉(zhuǎn)速為n=4000r/min汽車發(fā)動(dòng)機(jī)使用外特性的TqT驅(qū)動(dòng)力與行駛阻力平衡圖車速ua滾動(dòng)阻力：F空氣阻力：F行駛阻力：Ff驅(qū)動(dòng)力：F利用matlab繪出出每一擋的驅(qū)動(dòng)力與行駛阻力平衡圖如下：圖SEQ圖\*ARABIC1汽車驅(qū)動(dòng)力與行駛阻力平衡圖最高車速和最大爬坡度最高車速點(diǎn)：REF_Ref320559896\h圖1汽車驅(qū)動(dòng)力與行駛阻力平衡圖中五擋驅(qū)動(dòng)力曲線與行駛阻du式中uai于是可得到該輕型貨車在2擋啟動(dòng)時(shí)的加速度倒數(shù)曲線應(yīng)該為：圖SEQ圖\*ARABIC3二擋行駛時(shí)的加速度倒數(shù)曲線繪制加速時(shí)間曲線對REF_Ref320611355\h圖3二擋行駛時(shí)的加速度倒數(shù)曲線中的數(shù)據(jù)進(jìn)行數(shù)值積分（本文中利用matlab梯形積分命令comtapz（）和trapz（）命令進(jìn)行數(shù)值積分），得到車速—時(shí)間曲線如下圖所示：圖SEQ圖\*ARABIC4二擋原地起步加速時(shí)間曲線由程序輸出當(dāng)加速至70km/h時(shí)的加速時(shí)間為：25.9869498936328s。另外如果用一擋起步的話相應(yīng)的加速度加速時(shí)間為：25.1332114245632s一擋原地啟動(dòng)相關(guān)相關(guān)曲線圖見附錄。附錄clear%%%%%%%%%%%%%%%Function:汽車?yán)碚撟鳂I(yè)1%%%%%%%%%%%%%%%%%%%%%Author:%%%%Email:%%%jlu@126.com%Date:2012/3/26%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%clc%基本參數(shù)%G:總重r:車輪半徑f:滾動(dòng)阻力系數(shù)m:總質(zhì)量%ita:傳動(dòng)系機(jī)械效率CDA:空氣阻力系數(shù)x迎風(fēng)面積%i0:主減速器傳動(dòng)比If:飛輪轉(zhuǎn)動(dòng)慣量%Iw1:二前輪轉(zhuǎn)動(dòng)慣量Iw2:二后輪轉(zhuǎn)動(dòng)慣量ig:變速器傳動(dòng)比%a:質(zhì)心至前軸的距離L：軸距hg：質(zhì)心高G=38062.8;r=0.367;f=0.013;ita=0.85;CDA=2.77;i0=5.83;If=0.218;Iw1=1.798;Iw2=3.598;a=1.947;L=3.2;hg=0.9;m=3880;n=600:1:4000;%繪制驅(qū)動(dòng)力與行駛阻力平衡圖k=0;Ff=G*f;%滾動(dòng)阻力forig=[5.562.7691.6441.000.793]k=k+1;%擋位Ft(k,:)=(-19.313+295.27*(n/1000)-165.44*(n/1000).^2+...40.874*(n/1000).^3-3.8445*(n/1000).^4)*ig*i0*ita/r;ua(k,:)=0.377*n*r/i0/ig;delta(k,:)=1+(Iw1+Iw2)/(m*r^2)+If*ig^2*i0^2*ita/(m*r^2);plot(ua(k,:),Ft(k,:),'LineWidth',2);holdonendu=linspace(0,max(ua(5,:)),100000);Fw=CDA*u.^2/21.15;plot(u,Fw+Ff,'r','LineWidth',1);%輸出驅(qū)動(dòng)力與行駛阻力平衡圖%求解最高車速symsnn;i0=5.83;ig=0.793;FT=(-19.313+295.27*(nn/1000)-165.44*(nn/1000)^2...+40.874*(nn/1000)^3-3.8445*(nn/1000)^4)*ig*i0*ita/r;FF=CDA*(0.377*nn*r/i0/ig)^2/21.15+Ff;FT=eval(FT);FF=eval(FF);s=solve(FF-FT);ua_max=0.377*eval(s(1))*r/ig/i0%輸出最高車速%求解最大爬坡度Fw1=CDA*ua(1,:).^2/21.15;Fo=Ft(1,:)-Fw1;DImax=max(Fo)/G;%最大動(dòng)力因數(shù)alpha=asin((DImax-f*sqrt(1-DImax^2+f^2))/(1+f^2));i_max=tan(alpha) %輸出最大爬坡度%計(jì)算最大爬坡度相應(yīng)的附著率Fzs2=G*(a*cos(alpha)/L+hg*sin(alpha)/L)%后輪點(diǎn)面法向反力s=i_max/(a/L)%加速性能評價(jià)ua1=max(ua(1,:));ua2=max(ua(2,:));ua3=max(ua(3,:));ua4=max(ua(4,:));%換擋時(shí)刻的速度ua_all=[ua(2,:)ua(3,:)ua(4,:)ua(5,:)];Fw_p=CDA*ua.^2/21.15;%每擋對應(yīng)的空氣阻力delta_a=delta*ones(1,length(Ft));a_p=(Ft-Fw_p-Ff)./(m*delta_a);%各擋加速度figure;%繪制汽車行駛加速度曲線fork=1:5plot(ua(k,:),a_p(k,:),'LineWidth',2)holdonend%二擋起步時(shí)加速度數(shù)據(jù)a=[(a_p(2,:).*(ua(2,:)>0&ua(2,:)<=ua2));a_p(3,:).*(ua(3,:)>ua2&ua(2,:)<=ua3);a_p(4,:).*(ua(4,:)>ua3&ua(2,:)<=ua4);a_p(5,:).*(ua(5,:)>ua4)];a_2=[a(1,:)a(2,:)a(3,:)a(4,:)];si=find(a_2(:,:)<0.06);a_2(si)=[];ua_all(si)=[];figure;plot(ua_all,1./a_2,'LineWidth',2)%繪制汽車二擋啟動(dòng)時(shí)加速度倒數(shù)曲線a2=a(1,:);a3=a(2,:);a4=a(3,:);a5=a(4,:);a2(a2(:,:)<0.06)=[];a3(a3(:,:)<0.06)=[];a4(a4(:,:)<0.06)=[];a5(a5(:,:)<0.06)=[];u=ua_all/3.6;du=0.377*r./(3.6*i0*[5.562.7691.6441.000.793]);t=[cumtrapz(1./a2)*du(2)cumtrapz(1./a3)*du(3)+trapz(1./a2)*du(2)...cumtrapz(1./a4)*du(4)+tra