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1、精選優(yōu)質(zhì)文檔-傾情為你奉上汽車運(yùn)用工程大作業(yè) 汽車動(dòng)力性計(jì)算（加速性能、最高車速、動(dòng)力因素加速時(shí)間和加速距離）已知：發(fā)動(dòng)機(jī)外特性、裝載質(zhì)量、整備質(zhì)量、總質(zhì)量、車輪半徑、傳動(dòng)系效率、滾動(dòng)阻力系數(shù)、空氣阻力系數(shù)×迎風(fēng)面積、主減速器速比飛輪轉(zhuǎn)動(dòng)慣量、兩個(gè)前輪轉(zhuǎn)動(dòng)慣量、四個(gè)后輪轉(zhuǎn)動(dòng)慣量、變速器速比、軸距、質(zhì)心至前軸距離、質(zhì)心高度。例如，已知數(shù)據(jù)如下表:項(xiàng)目單位數(shù)值裝載質(zhì)量kg1995整備質(zhì)量kg1700總質(zhì)量kg3695車輪半徑m0.37傳動(dòng)系效率0.87滾動(dòng)阻力系數(shù)0.012空氣阻力系數(shù)×迎風(fēng)面積m22.60主減速器速比5.83飛輪轉(zhuǎn)動(dòng)慣量kgm20.22兩前輪轉(zhuǎn)動(dòng)慣量kgm21

2、.80四后輪轉(zhuǎn)動(dòng)慣量kgm23.60軸距m3.40質(zhì)心至前軸距離m2.0質(zhì)心高度m0.9變速器速比變速器I檔II檔III檔IV檔V檔四檔6.123.111.691.00五檔3.552.771.651.000.83發(fā)動(dòng)機(jī)外特性 Tq=a+a1(n/c)+a2(n/c)2+a2(n/c)3+a3(n/c)4 參數(shù)aa1a2a2a3c數(shù)值-19.31296-16540.9-3.8510001) 繪制汽車驅(qū)動(dòng)力與行駛阻力平衡圖；2) 求汽車的最高車速、最大爬坡度；3) 繪制加速度倒數(shù)曲線4) 用圖解法或編程繪制汽車動(dòng)力因數(shù)特性曲線5) 圖解手工繪制II檔起步，加速至70km/h的車速時(shí)間曲線以及距離時(shí)

3、間曲線。1、繪制汽車驅(qū)動(dòng)利于行駛阻力平衡圖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=1

4、000;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,ft

5、4,ua1,fz1,ua2,fz2,ua3,fz3,ua4,fz4);title('驅(qū)動(dòng)力與行駛阻力平衡圖');Xlabel('ua(km/h)');Ylabel('ft(N)'); gtext('Ft1') gtext('Ft2') gtext('Ft3') gtext('Ft4') gtext('Ff+Fw')2、求汽車的最高車速、最大爬坡度1）汽車的最高車速當(dāng)Ft=Ff+Fw時(shí),汽車處于穩(wěn)定狀態(tài),并達(dá)到最高車速 用matlab對(duì)驅(qū)動(dòng)力與行駛阻力圖進(jìn)行放大處理可得

6、交點(diǎn)坐標(biāo)為（106.53，1757.68）因此，uamax=106.53km/h2）最大爬坡度一檔時(shí)有最大爬坡度, 用matlab對(duì)驅(qū)動(dòng)力與行駛阻力圖進(jìn)行放大處理可得當(dāng)ua=8.56km/h時(shí)，F(xiàn)t1-(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

7、;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輸出：ft1 =15415Nfz1 =371.4871Ni=tan=tanarcsin(ft1-fz1)/(mz.*g)可知： =24.02°.i=tan=0.443、繪制加速度倒數(shù)曲線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

8、;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.

9、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

10、;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('加速度倒數(shù)曲線圖');Xlabel('ua(km/h)');Yla

11、bel('1/a(m/s2)');gtext('1/a1') gtext('1/a2') gtext('1/a3') gtext('1/a4') 4、用圖解法或編程繪制汽車動(dòng)力因數(shù)特性曲線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/(

12、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

13、+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;D

14、2=(ft2-fw2)./G;D3=(ft3-fw3)./G;D4=(ft4-fw4)./G;plot(ua1,D1,ua2,D2,ua3,D3,ua4,D4)title('汽車動(dòng)力特性圖');Xlabel('ua(km/h)');Ylabel('D');gtext('') gtext('') gtext('') gtext('')5、圖解手工繪制檔起步，加速至70km/h的車速時(shí)間曲線以及距離-時(shí)間曲線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;d