NHN XT CA GIO VIN HNG DN

Thnh ph H Ch Minh ngy......thng........nm 2013

GVC.MSc. ng Qu.

NHN XT CA GIO VIN DUYT

Thnh ph H Ch Minh ngy......thng........nm 2013

LI NI U

Ngy nay giao thng vn ti ang ng vai tr v cng quan trng trong s pht trin nn kinh t x hi ca mt quc gia. Thc vy nc ta c s h tng v giao thng vn ti ang pht trin mt cch mnh m nhm p ng nhu cu i li v vn chuyn hng ha. Vit Nam c cc loi giao thng vn ti nh: ng st , ng thy, ng hng khng, nhng giao thng vn ti bng ng b vn chim t l cao nht. Cng vi s pht trin kinh t x hi th nhu cu i li ca ngi dn ngy cng cao, trong khi c s h tng, h thng ng x ca nc ta vn l bi ton nan gii, v vy mt phng tin i li nh gn v c sc cha nhiu ngi l mt trong nhng phng n hiu qu gii quyt bi ton trn. Xe TOYOTA ALTIS l loi xe du lch c sn xut bi hng TOYOTA. Nhm mc ch nghin cu tnh nng s dng v tm ra u nhc im ca xe TOYOTA ALTIS a ra cc thng s ca xe gip cho ngi s dng hiu r v tnh nng ca xe s dng xe ph hp vi iu kin giao thng nc ta hin nay, V vy nhm c giao thc hin ti: Nghin cu ng hc v ng lc hc ca xe TOYOTA ALTIS 2010

Sau gn 3 thng thc hin, vi s hng dn tn tnh ca thy MSc. ng Qu gip chng em hon thnh ti ny. Bn cnh cng cn c nhng thiu xt trong qu trnh thc hin ti, chng em mong c s nh gi v gp ca cc thy c ti c th hon thin hn.

MC LC

LI CM N

Knh tha cc thy c cng ton th cc bn sinh vin thn mm, mi thm thot bn nm tri qua ri. Nh bui u tin khi chng em mi bc chn chp chng vo ngi trng I HC S PHM K THUT TP.HCM, vi bit bao nhiu s b ng v hi hp khng bit mnh s hc nh th no, ngnh ca mnh ra s lm c nhng g.Nhng tri qua bn nm hc ti ngi trng thn yu ny vi s gip ca cc thy c ni chung v ca cc thy trong khoa C KH NG LC ni ring. Cc thy c khng nhng trang b cho chng em nhng kin thc phc v cho cuc sng x hi khi ra trng m cc thy c cn rn luyn cho chng em nhng c tnh v tc phong trong cng nghip, gip chng em mnh dn v t tin hn khi ng trc mi ngi. Cng n ca cc thy c i vi chng em v cng to ln v khng c g c th so snh c. Li cui em xin chc cc thy c mnh khe, hnh phc. V s tip tc du dt nhiu th h sinh vin nh chng em na c th t tin bc vo i.

Tp.HCM Ngy 18 Thng 01 Nm 2013

LI CM N

Chng 1: M U

T VN :

Ngy nay giao thng vn ti ang ng vai tr rt quan trng i vi s pht trin ca kinh t x hi, trong giao thng ng b chm v tr quan trng nht. Cng vi s pht trin x hi l nhu cu i li ngy cng tng th phng tin i li s l mt lnh vc c x hi quan tm nhiu. Trong t ang l s la chn rt nhiu c nhn v t chc trong x hi. Vit Nam do tnh trng ng x cha c tt nn vic nghin cu c c mt chic xe c th p ng c nhu cu ca con ngi v c kh nng chu ng tt vi iu kin ng x l nhiu v quan trng ca nghnh t Vit Nam. ti Nghin cu ng hc v ng lc hc ca xe TOYOTA ALTIS s gip xe hot ng tt trn cc loi ng v to s an ton cho ngi s dng xe.

NI DUNG THC HIN:

M u v gii hn vn . Tnh ton xy dng ng t tnh ngoi ca ng c. Tnh ton kim tra cn bng lc ko,cn bng cng sut v t tnh ng lc hc ca xe. Tnh ton, kim tra tnh n nh ca xe. Nghing cu ng hc v ng lc hc quay vng ca xe. Kt lun.

BNG THNG S K THUT CA XE TOYOTA ALTIS 1.8G nm 2010

T TNH K THUTM T

ng c1.8lt (2ZR-FE)

Hp s6 s tay

S ch ngi5 ch

KCH THC V TRNG LNG

Kch thc tng th ( di x rng x cao) (mm)4500x1760x1465

Chiu di c s (mm)2600

Chiu rng c s ( Trc x sau)(mm)1530x1535

Bn knh quay vng ti thiu(m)5,3

Khong sng gm xe(mm)155

Khi lng khng ti(kg)11701230

Khi lng c ti(kg)1605

Dung tch cng tc(cc)1798

Cng sut ti a(kW/rpm)103/6400

Mmen xon t a(Nm/rpm)191.99/3000

Khong cch gia 2 ng tm tr ng ti v tr t cc cam quay ca cc bnh xe dn hng (m)q = 1,04

Dung tch bnh nhin liuLt55

Tiu chun kh thiEuro2

Khung gm

H thng treo trcKiu MacPherson

H thng treo sauThanh xon

H thng phanh trca thng gi 15

H thng phanh saua 15

C cu liTr lc Eps

Lp xe195

Mm xeMm c

Trang thit b chnh

Ngoi tht

n trcHalogen

Ch iu chnh gc chiuKhng

n xng m pha trcC

Cm n sauLed

Gng chiu hu ngoiMuGp inTch hp n bo rCng mu thn xeCC

H thng kha ca thng minhKhng

Kha ca t xaC

H thng gt maGin on/ iu chnh thi gian

Ni tht

Tay liiu chnh 4 hngNt chnh m thanhThit kCC4 chu, bc gia

Ca s inC

Kha ca trung tmC

H thng khi ng bng nt nhnKhng

Tay nm cn sBc gia v M bc

iu ha nhit Chnh tay

An ton

ABS v EBDC

H thng h tr phanh khn cpC

Cm bin liC

H thng chng trmC

H thng ti khNgi li v hnh khch pha trc

Dy ai an tonTt c cc gh

Loi hp sEC60

Loi ng c2ZR-FE

T s truyn1st3.538

2nd1.913

3rd1.310

4th0.971

5th0.818

6th0.700

S li3.333

T s ca truyn lc chnh4.294

Th tch du bi trn (Lt)2.4

Cp nht ca du bi trnSAE 75W

Cp cht lng du bi trnAPI GL-4

Chng 2 : TNH TON V XY DNG NG C TNH NGOI CA NG C.

NH NGHA NG C TNH NGOI CA NG C.

ng c tnh ngoi ca ng c l th ch s ph thuc ca ng cng sut c ch , moment xon c ch , v cng sut tiu hao nhin liu , theo s vng quay hoc theo tc ca trc khuu ng c ch cung cp nhin liu cc i, tc l bm ga m hon ton i vi ng c xng hoc thanh rng cung cp nhin liu ti a i vi ng c diesel.

TNH TON V XY DNG NG C TNH NGOI CA XE TOYOTA ALTIS 1.8G 2010.

Xc nh cng xut hu ch ca ng c.

Da vo cng thc S.R.Ly cman:

Trong : : cng sut c ch (kW) : s vng quay trc khuu ng c ( vg/ph) v tng ng cng sut hu ch cc i v s vng quay ng vi cng sut ni trn.a,b,c cc h s thc nghim chn theo loi ng c.ng c trn xe TOYOTA ALTIS l ng c xng 4 k nn:a=b=c=1thay vo phng trnh Pe ta c:

T cc gi tr v ta c th xc nh c cc gi tr mmen xon ca ng c theo cng thc sau:

Trong : : Mment quay ca ng c (Nm): Cng sut c ch ca ng c (kW): S vng quay ng c (vg/ph)T cng thc trn ta c cc gi tr v tng ng vi cc gi tr = (800 7000) theo bng sau:

Bng 1: Gi tr cng sut c ch v mmen ca ng c ng vi s vng quay ng c.

(vg/ph)( kW)(Nm)

80014,283170,523

100018,215173,973

150028,472181,293

200039,103186,738

250049,81190,304

300060,304191,990

350070,286191,802

400079,463189,740

450087,439185,8000

500094,230179,981

550099,213172,289

6000102,220162,719

6400103153,713

7000101,105137,952

Hnh 1: ng c tnh tc ngoi ca ng c.

Nhn xt : T th trn ta thy khi cng sut t gi tr cc i ng vi s vng quay (np=6400) m ta tip tc tng s vng quay ( tip tc p ga ) th cng sut ca ng c khng nhng khng tng m gim nhanh v gi tr khng v nu nh tc ca ng c nh hn nM th ng c hot ng khng n nh. Cng sut cc i ca ng c l Pemax=103 (kW) s vng quay neP= 6400(vg/ph). Mment xon cc i Memax = 191.99(Nm) s vng quay neM= 3000 (vg/ph). Mment xon ng vi cng sut cc i ( gi l mment xon nh mc ) MeP=153,713(Nm). T th trn ta cng thy khi s vng quay ca ng c ln hn nN th mment ca ng c cng gim nhanh v n khng v nu s vng quay ng c gim t nN n nM th mment ca ng s tng v t gi tr cc i ti nM, nu tip tc gim th mment gim khi ng c s hot ng khng n nh. Nh vy ng c s hot ng khng n nh khi s vng quay ca ng c nm trong khong t n khi ng c s pht huy c ht cng sut ca n v gn t gi tr nh mc. Da vo th c tnh ngoi ca ng c chng ta c th tin hnh kho st cn bng lc ko, cng sut v t tnh ngoi ca ng lc hc ca xe.

Chng 3: KHO ST CN BNG LC KO, CNG SUT V C TNH NG LC HC CA XE.

CC LC TC DNG LN T V CNG SUT TNG NG KHI CHUYN NG.

Cc lc tc dng ln t khi xe chuyn ng.

Chng ta xt chuyn ng t dng tng qut l khi t chuyn ng trn ng dc khng n nh (c gia tc).

Hnh 2: S lc v mment tc dng ln xe khi chuyn ng ln dc.

Trn hnh 2 trnh by s cc lc v mment tc dng ln t khi xe chuyn ng tng tc trn ng dc. ngha ca cc k hiu trn hnh v nh sau:Ff1: Lc cn ln cc bnh xe ch ng.Ff2: Lc cn ln cc bnh xe b ng.G: Trng lng ton b ca xe.FK: Lc ko tip tuyn cc bnh xe ch ng.: Lc cn khng kh.: Lc cn ln dc.: Lc cn qun tnh khi xe chuyn ng khng n nh., : Phn lc php tuyn ca mt ng tc dng ln bnh xe cu trc, cu sau.: Mment cn ln cc bnh xe b ng.: Mment cn ln cc bnh xe ch ng. : gc dc ca mt ng.Sau y ta s kho st cc gi tr ca cc lc v mment va nu trn. Trng lng ton b xe.G = 1605.10 = 16050 (N) Lc ko tip tuyn cc bnh xe ch ng.

Trong :: Mment xon ca ng c ( c xc nh trong phn tnh ton c tnh ngoi.) = { 3,538;1,913;1,310;0,971;0,818;0,700 }:T s truyn ca hp s.=4,294 : T s truyn ca truyn lc chnh.= 0,87 : Hiu sut truyn lc.=0,3(m) : Bn knh tnh ton ca bnh xe.

Lc cn ln:

nu v 22 m/s (80km/h)

Nu v 22 (m/s)

Trong :: H s cn ln ca mt ng c tnh theo bng di.v : Tc chuyn ng ca xe tnh theo (m/s).

Bng 2 : H s cn ln ca cc loi ng.

Loi ngH s cn ln f

Nha tt 0,0150,018

Nha b tng0,0120,015

Ri 0,0230,030

t kh0,0250,035

t sau khi ma0,0500,150

Ct0,1000,300

t sau khi cy0,120

Mmen cn ln :Mmen cn ln ca xe c tnh: y : : Mmen cn ln cc bnh xe cu trc v cu sau.: Bn knh ng lc hc ca xe. Lc cn ln c :

Mc dc ca mt ng c th hin qua gc dc hoc qua dc i :i= tgNu 22 m/s).

T cc cng thc tnh ton ta c :

Bng 3: Gi tr cc vn tc ng vi s vng quay ng c.

neV1(m/s)V2(m/s)V3(m/s)V4(m/s)V5(m/s)V6(m/s)

8001,6543,0604,4686,0287,1558,361

10002,0683,8245,5857,5358,94410,452

15003,1025,7378,37711,30213,41615,678

20004,1367,64911,17015,06917,88820,904

25005,1709,56113,96218,83722,36026,129

30006,20411,47316,75522,60426,83231,355

35007,23813,38619,54726,37231,30436,581

40008,27215,29822,34030,13935,77641,807

45009,30617,21025,13233,90640,24847,033

500010,34019,10227,92537,67444,72052,259

550011,37321,03530,71741,44149,19257,485

600012,40722,94733,50945,20853,66462,711

640013,23424,47735,74348,22257,24266,891

700014,47526,77139,09452,74362,60873,162

Bng 4:Gi tr lc ko ta xy dng c.

Fk1(N)Fk2(N)Fk3(N)Fk4(N)Fk5(N)Fk6(N)

7512,84062,22781,72061,917371486,4

7664,84144,428382103,61772,11516,5

7987,34318,72957,42192,11846,71580,3

8227,24448,43046,22257,91902,21627,8

8384,34533,43104,423011938,51658,8

8458,64573,63131,92321,41955,71673,5

8450,34569,13128,823191953,71671,9

8359,445203095,22294,21932,71653,9

8185,84426,13030,92246,61892,61619,6

7929,54287,529362176,21833,31568,9

7590,64104,22810,52083,217551501,8

71693876,32654,41967,51657,61418,4

6772,23661,72507,51858,61565,81339,9

6077,83286,32250,416681405,21202,5

Bng 5: Gi tr lc cn:

V(m/s)Fc (N)Ff(N)

0241241

5248241

10271241

15309241

20361241

25528341

30355385,2

35805437,4

40978497,6

451173565,8

501392642

551634726,3

601899618,6

652187918,8

Hnh 3: th cn bng lc ko.

Ta c ta cc im a,b,c,d ng vi vn tc 40(m/s) tay s 6:d (40;1660)c (40;1058)b (40;497,6)a (40;0)

ngha ca th:

Trn th , t im A l giao im gia ng Fk6 tay s cao nht vi ng cong lc cn trn ng F+F h ng thng t A vung gc vi trc honh , ta xc nh c vn tc cc i ca xe vi iu kin chuyn ng cho vmax= 53,664(m/s) =193(km/h).T th ta c th xc nh c vmax v cc lc cn thnh phn mt vn tc no .V d: ti vn tc v=40(m/s) = 144(km/h) on ab l F =Ff =497,6 (N).on bc l F= 1058-497,6 = 560,4(N).on cd l Fd ( lc ko d dng tng tc , leo dc...)Fd = 1660-1058 = 602(N).

KHO ST CN BNG CNG SUT.

Phng trnh cn bng cng sut.

Ta c: tnh ton n gin v thun tin cho vic xc nh vn tc cc i ca xe.Ta xt chuyn ng ca xe trong iu kin trn ng nha tt bng phng (,xe ang chuyn ng u (j0)Khi :

Phng trnh cn bng cng sut ti bnh xe ch ng c vit li:

th cn bng cng sut.

V cc ng biu th cng sut cc tay s da vo cng thc:

V ng biu din cng sut cn tng :Pc = 241.v+0,3.v3 ( nu v 22 m/s ).

( nu v > 22 m/s)T cng thc trn tnh ton ta c bng gi tr sau:

Bng 6: Gi tr cng sut tnh c.

Pk1(kW)Pk2(kW)Pk3(kW)Pk4(kW)Pk5(kW)Pk6(kW)Pc(kW)Pf(kW)

12,42612,43012,42812,42912,42812,42800

15,85115,48415,85015,85015,84815,8501,2421,205

24,77724,77624,77424,77524,77524,7762,7102,410

34,02834,02634,02630,02434,02634,0864,6273,615

43,34743,34443,34343,34443,34543,3107,2204,820

52,47752,47352,47552,47352,47552,47213,2228,256

61,16361,16061,15861,15761,15861,16019,66811,556

69,41569,14769,17469,14569,14469,14428,18615,307

76,17776,17376,17276,17376,17375,70039,12219,902

81,99081,89681,98881,98581,98581,98952,82325,459

86,32886,33086,33086,33286,33286,33169,63332,100

88,94688,94988,94688,94888,94888,94989,89839,944

89,62389,62789,62689,62989,62989,627113,96449,113

87,97687,97787,97787,97787,97787,977142,17559,726

ngha ca th:

Trn th , t im A l giao im gia ng v ng cong ,h ng thng vung gc xung trc honh, ta xc nh c vn tc cc i ca xe iu kin chuyn ng cho.(53,664m/s)193(km/h), ( ph hp vi phng trnh cn bng lc ko ).T th ta c th xc nh c v cc cng sut cn thnh phn mt vn tc no .V d: Ti vn tc (40m/s) 144 (km/h). on ab l 19,902 (kW).on bc l 39,12219,902 = 19,220 (kW).on cd l ( cng sut d dng tng tc,leo dc,). 66,50039,12227,378 (kW).

KHO ST C TNH NG LC HC CA T.

c tnh ng lc hc.

Khi so snh tnh cht ng lc hc ca cc loi t khc nhau v ng vi cc iu kin lm vic ca xe cc loi ng khc nhau, ngi ta mun c mt thng s th hin c ngay tnh cht ng lc hc ca t. Phng trnh cn bng lc ko khng thun li nh gi cc loi t khc nhau cho nn cn phi c mt thng s c trng cho tnh cht ng lc hc ca xe m ch s kt cu khng c mt trong . Thng s gi l c tnh ng lc hc ca t, k hiu l D.

T phng trnh cn bng lc ko:

Vi iu kin chuyn ng cho.

th c tnh ng lc hc.

Da vo cng thc:

Ta v cc ng D theo cc tay s.V ng biu th h s cn ln, f0,015 nu v 22 (m/s), tc 80 (km/h) Nu v 22 (m/s)

Bng 7: c tnh ng lc hc.

D1D2D3D4D5D6f

0,4680,2530,1730,1280,1070,0910,015

0,4770,2580,1760,1300,1090,0920,015

0,4970,2680,1830,1340,1110,0940,015

0,5120,2760,1870,1360,1130,0930,015

0,5220,2810,1900,1370,1110,0910,015

0,5260,2820,1900,1350,1080,0860,02

0,5250,2810,1880,1310,1030,0790,024

0,5190,2770,1840,1260,0960,0700,027

0,5080,2700,1770,1180,0880,0600,031

0,4920,2600,1680,1090,0770,0470,035

0,4700,2470,1570,0980,0640,0320,04

0.4430,2320,1440,0840,0490,0150,045

Hnh 5: th c tnh ng lc hc ca xe.

Ta c to cc im a,b,c,d ng vi vn tc l 30 (m/s) ca cc tay s:d(30;0,131)c(30;0,108)b(30;0,086)a(30;0,024)

ngha s dng th:

Xc nh vn tc ln nht ca xe:

T th, chiu im A trn ng xung vung gc trc honh ta c vn tc ln nht ca xe. 53,664 (m/s) 193 (km/h)

Xc nh dc ln nht m xe c th vt:

dc ln nht m xe c th vt tng tay s:Tay s 1:

y cng chnh l dc ln nht m xe c th khc phc.Tay s 2:

Tay s 3:

Tay s 4:

Tay s 5:

Tay s 6:

dc ln nht m xe c th khc phc c vn tc bt k ca tng tay s.v30(m/s)108(km/h) vi cc tay s khc nhau l:Tay s 4:

Xc nh kh nng tng tc ca t:

Xc nh kh nng tng tc tng tay s.Tay s 1:

Xc nh kh nng tng tc ti vn tc bt k:V d : Ti v 30 (m/s) 108 (km/h)

th biu din gia tc ca xe:+ T cng thc:

+ Cc gi tr (D ly t th ( D v ) hnh 5.V =0 nn c xc nh t:

Bng 8: Gi tr gia tc.

j1(m/s2)j2(m/s2)j3(m/s2)j4(m/s2)j5(m/s2)j6(m/s2)

2,6501,8931,3641,0100,8330,694

2,7501,9331,3901,0280,8510,703

2,8202,0131,4511,0640,8690,722

2,9092,0761,4851,0820,8880,712

2,9672,1161,5111,0910,8400,642

2,9912,1241,5111,0480,7940,567

2,9852,1161,4930,9940,7200,474

2,9502,0841,4430,9300,6280,354

2,8852,0291,3730,8390,5260,241

2,7921,9491,2760,7290,3880,045

2,6631,8461,1710,6020,2300

Hnh 6: th biu din gia tc ca xe.

Nhn xt:

Khi tc xe tng th gia tc tng. Khi tc xe tng n v tr nht nh th gia tc ca xe bt u gim. Ti v tr 53,664 (m/s) th j0.

Chng 4: TNH TON KIM TRA TNH N NH CA XE.

Tnh n nh ca t l kh nng bo m gi c qu o chuyn ng theo yu cu trong mi iu kin chuyn ng khc nhau.Ty thuc iu kin s dng ,t c th ng yn,chuyn ng trn ng dc,c th quay vng hoc phanh cc loi ng khc nhau(ng tt,ng xu). Vi nhng iu kin phc tp nh vy, t phi gi c qu o ca n sao cho khng b lt , khng b trt, cu xe b quay lch trong gii hn cho php m bo chng chuyn ng an ton nng cao vn tc chuyn ng ca xe, c ngha l tng tnh kinh t v tnh n nh ca t trong mi iu kin lm vic. y ta nghing cu tnh n nh ca xe TOYOTA ALTIS nhm bo m kh nng khng b lt hoc b trt trong cc iu kin chuyn ng khc nhau.

N NH DC CA XE.

1.n nh dc tnh:

Kh nng m bo cho t khng b lt hoc b trt khi ng yn trn ng dc dc.

Xt trng hp xe ng yn trn ng nm ngang.

Trong trng hp ny ch c ba lc tc dng ln xe. Trng lng ton b ca xe G v cc phn lc thng ng tc dng ln cc bnh xe cu trc v cu sau trng thi tnh v

Hnh 7:S lc tc dng ln xe khi ng yu.

Theo s liu t nh my TOYOTA Vnh Phc ta c: a=1,236 (m), b=1,364 (m), hg=0,683 (m). Ly m men ti im ta c:G.a

Xt n nh theo iu kin lt :

Xe u trn ng dc u hng ln.

Hnh 8:S lc v mmen tc dng ln t khi ng yn quay u ln dc.

Xu hng lt : Xe c xu hng lt quanh trc nm trong mt phng ca ng v i qua im tip xc ca hai bnh xe cu sau vi mt ng (im ) theo phng dc. Trng thi gii hn lt : Khi gc tng dn n gc ( gc gii hn m xe b lt khi ng quay u ln dc) th cc bnh xe cu trc nhc khi mt ng. khi 0.Ta lp phng trnh mmen qua im : G..sin

Xe u trn ng dc u hng xung:

Hnh 9: S lc v mmen tc dng ln t khi ng yn quay u xung dc.

Khi t quay u xung dc th xe c xu hng lt quanh trc nm trong mt phng ca ng v i qua im tip xc ca hai bnh xe cu trc mt ng (im ), khi gc tng dn n gc ( gc gii hn m xe b lt khi ng yn quay u xung dc) th cc bnh xe cu sau nhc khi mt ng: Ly m men qua im :

ta c:

Khi gc tng dn n gc th ta c:

.

Xt n nh theo iu kin trt:

Xe ang xt dng h thng phanh tay l phanh cu sau nn ta ch xt trng hp lc phanh tay xut hin cu sau . Nh vy ta xt lc phanh t ti gii hn bm,xe c th b trt xung dc,gc dc khi xe b trt c xc nh nh sau:G.sin. (4.3)

Trong :

:Lc phanh ln nht bnh xe trc :H s bm dc ca xe vi mt ng.:Hp lc ca cc phn lc thng gc t ng tc dng len cc bnh xe trc.1.3.1.Trng hp xe ng yn trn dc quay u ln.

tng ti (gc dc gii hn m t bt u b trt khi ng yn quay u ln dc), th lc lc phanh t ti gii hn bm.G..sin

Thay vo (4.3) ta c:

L.sin sin

1.3.2 Trng hp xe ng yn trn dc quay u xung:

Khi tng dn n th lc phanh t ti gii hn bm:

Thay vo (4.3) ta c:

L.sin sin

Trong :

v l gc gii hn khi xe ng yn quay u ln dc.

Nhn xt:

c gii hn khi xe ng trn dc ch ph thuc vo ta trng tm v cht lng ca mt ng.Nh vy ta s xt cc trng hp khi xe u trn cc loi ng c h s bm khc nhau.

Bng 9:H s bm dc v gc dc gii hn ca xe.

H s bm dc Xe quay u ln dc(Xe quay u xung dc(

0,825 4117o 25

0,7523 5616o35

0,722o 1815o 41

0,6520 1014o 47

0,618o 4213o 49

0,5516o 5912o 50

0,515o 1811o 51

0,4513o 4910o 48

0,411o 599o 45

0,3510o 228o 38

0,38o 477o 31

0,257o 146o 21

0,25o 435o 8

0,154o 143o 55

0,12o 472o 39

Bng 10: H s bm dc v gc dc gii hn m xe b trt xung dc.

TTLoi ngTnh trngH s bm xtt

1ng b tng nha, b tng xi mng miKh0,70,822o1825o4115o 4117o 25

t0,50,615o 1818o 4211o 5113o 49

2ng b tng nha, b tng xi mng mn schKh0,50,615o 1818o 4211o 5113o 49

t0,350,4510o 2213o 4911o 2510o 48

3ng b tng nha, b tng xi mng c t bnKh0,40,511o 5915o 189o 4511o 51

t0,30,48o 4711o 597o 319o 45

4ng lt

Kh0,450,713o 4922o 1810o 4815o 41

t0,30,48o 4711o 597o 319o 45

5ng ri

Kh0,450,6513o 4920 1010o 4814o 47

t0,30,48o 4711o 597o 319o 45

6ng dm

Kh0,450,513o 4915o 1810o 4811o 51

t0,30,458o 4713o 497o 3110o 48

7ng t nn chtKh0,50,615o 1818o 4216o 4713o 49

t0,30,48o 4711o 597o 319o 45

8ng t ct

Kh0,50,615o 1818o 4211o 5113o 49

t0,60,718o 4222o 1813o 4915o 41

9ng t tnh trng xu( c bn ly)Kh0,150,34o 148o 473o 557o 31

t0,10,152o 474o 142o 393o 55

Nhn xt:

Sau khi tnh ton v so snh ta thy rng gc v tha mn theo iu kin trt v theo iu kin lt . Do xe m bo an ton.

n nh dc ng:

Khi t chuyn ng trn ng dc c th b mt n nh (lt hoc trt) di tc dng ca cc lc v mmen hoc b lt khi t chuyn ng tc cao trn ng bng.

Trng hp xe chuyn ng ln dc vi vn tc nh:

Hnh 10 :S lc v mmen tc dng ln t khi ln dc vi vn tc nh.

Xt n nh theo iu kin lt :

Khi xe chuyn ng ln dc vi gc :

Khi gc tng dn n gi tr gii hn th xe s b lt quanh trc qua im tip xc ca hai bnh xe cu sau vi mt ng (im ) lc .Ly mmen qua im ta c:G.

Khi th

b.cos sin

Thay cc gi tr b,vo cng thc (4.7) ta c:

. Khi xe chuyn ng xung dc vi gc :

Khi gc tng n gi tr ti hn th xe b lt quanh trc qua im tip xc hai bnh xe cu trc vi mt ng (im ) lc

Khi th

Xt n nh theo iu kin trt:

V xe TOYOTA ALTIS ch c cu trc ch ng nn khi lc ko ch ng t ti gii hn bm th xe bt u trt:Ta c: Mt khc ta c:

hay vo cng thc (4.9) ta c:

th xe bt u trt, da vo cng thc (4.9) v (4.10) ta xc nh dc gc dc gii hn m xe b trt.L.sin sin

T cng thc (4.11) ta thy rng gi tr ca gc ph thuc vo ta trng tm ca xe v cht lng mt ng. Nh vy ta s xt gc dc m xe trt trn nhiu loi ng khc nhau.

Bng11:H s bm dc v gc dc gii hn m xe b trt.

TTLoi ngTnh trngH s bm xt

1ng b tng nha, b tng xi mng miKh0,70,817o1319o8

t0,50,613o 315o 12

2ng b tng nha, b tng xi mng mn schKh0,50,613o 315o 12

t0,350,459o 3211o 54

3ng b tng nha, b tng xi mng c t bnKh0,40,510o 4513o 3

t0,30,48o 1810o 45

4ng lt

Kh0,450,711o 5417o 13

t0,30,48o 1810o 45

5ng ri

Kh0,450,6511o 5416 13

t0,30,48o 1810o 45

6ng dm

Kh0,450,511o 5413o 3

t0,30,458o 1811o 54

7ng t nn chtKh0,50,613o 315o 12

t0,30,48o 1810o 45

8ng t ct

Kh0,50,613o 315o 12

t0,60,715o 1217o 13

9ng t tnh trng xu( c bn ly)Kh0,150,34o 208o 18

t0,10,152o 554o 20

Trng hp xe chuyn ng n nh vi vn tc cao trn ng nm ngang.

Hnh 11:S lc v mmen tc dng ln xe khi chuyn ng trn ng nm ngang.

Trong trng hp ny ta c:, b qua nh hng ca lc cn ln. S lc v mmen tc dng ln xe nh hnh trn. Khi xe c kh nng b lt do lc cn khng kh gy ra nu chuyn ng vi vn tc rt ln. Lc cn khng kh tng ti gi tr ti hn, xe s b lt quanh im ( l giao im ca mt phng qua trc bnh xe sau vi ng ), lc phn lc 0. xc nh vn tc gii hn m xe b lt ta ly mmen vi im :

M nn ta c:

Ta coi v tr s ca n rt nh so vi , thay gi tr v rt gn ta c vn tc nguy him m xe lt .

: Vn tc tng i gia xe v khng kh (m/s). : Vn tc ti hn m xe b lt (m/s). : Nhn t cn khng kh:W c n v l (N./ : H s cn khng kh c n v (N./ S : Din tch cn khng kh c n v (Ta c:G16050 (N).b1,364 (m).0,30,5 , ta chn 0,31,62,5 , ta chn 1,6 0,625.0,3.1.6 0,3 0,683(m).Thay cc gi tr trn vo cng thc(4.12) ta c:

N NH NGANG CA XE KHI CHUYN NG THNG TRN NG NGHING NGANG.

Hnh 12: S lc v mment tc dng ln xe khi chuyn ng trn ng nghing ngang.

Trong :, : Phn lc ngang tc dng ln cc bnh xe bn phi v bn tri. : Gc nghing ngang ca ng. : Phn lc thng gc t ng tc dng ln cc bnh xe bn phi v bn tri. : Mmen ca lc qun tnh tip tuyn tc dng trong mt phng ngang khi t chuyn ng khng n nh.

Xt n nh theo iu kin lt .

t c xu hng lt quanh trc nm trong mt phng ca ng v i qua im tip xc ca hai bnh xe bn tri vi mt ng (im B) nh hnh trn.Ly mmen i vi im B ta c :

Khi gc tng ti gi tr ti hn tho xe lt quanh trc qua im B. Lc . Thng thng gi tr nh nn c th coi Ta xc nh c gc gii hn lt khi xe chuyn ng trn ng nghing ngang l:

Vi c 1,530 (m) v 0,683 (m) , ( theo ti liu k thut ca xe ).

Xt n nh theo iu kin trt.

Khi cht lng bm ca bnh xe vi ng km th xe c xu hng trt khi xe chuyn ng trn ng nghing ngang. xc nh gc gii hn khi xe b trt, ta lp phng trnh hnh chiu cc lc ln mt phng song song vi mt ng.G.sin .Trong : : Gc dc gii hn m xe b trt. : H s bm ngang gia bnh xe vi mt ng.Rt gn biu thc (4.15) ta c:

Nhn xt: Gc dc gii hn m xe b trt xung dc ph thuc vo h s bm ngang ca bnh xe vi mt ng. Nh vy ta s xt gc dc m xe b trt trn cc loi ng khc nhau.

Bng 12: H s bm ngang v gc dc gii hn m xe b trt ngang.

TTLoi ngTnh trngH s bm yGc gii hn m t b trt

1ng b tng nha, b tng xi mng miKh0,80,938,66o41,99o

t0,60,730,96o 35o

2ng b tng nha, b tng xi mng mn schKh0,60,730,96o 35o

t0,450,5524,23o28,81o

3ng b tng nha, b tng xi mng c t bnKh0,50,626,56o30,96o

t0,40,521,8o 26,56o

4ng lt

Kh0,550,828,81o38,66o

t0,40,521,8o25,56o

5ng ri

Kh0,550,7528,81o36,87

t0,40,521,8o 25,56o

6ng dm

Kh0,550,628,81o30,96o

t0,40,5521,8o28,81o

7ng t nn chtKh0,60,730,96o35o

t0,40,522,8o25,56o

8ng t ct

Kh0,60,730,96o35o

t0,70,835o38,66o

9ng t tnh trng xu( c bn ly)Kh0,250,414,04o21,8o

t0,20,2511,31o14,04o

Chng 5 : NGHING CU NG HC V NG LC HC QUAY VNG CA XE.

NG HC QUAY VNG CA XE.

Ta xt ng hc quay vng ca xe khi b qua bin dng ngang ca cc bnh xe do n hi ca lp. Nu khng tnh n bin dng ngang ca lp, th khi quay vng vct vn tc chuyn ng ca bnh xe s trng vi mt phng quay ( mt phng i xng ) ca bnh xe.Hnh di m t ng hc quay vng ca t c hai bnh dn hng cu trc khi b qua bin dng ngang ca lp. trn s : A, B l v tr ca hai tr ng.

Hnh 13: S ng hc quay vng ca xe khi b qua bin dng ngang. E l im gia ca AB, l gc quay vng ca bnh xe dn hng bn ngoi v bn trong so vi tm quay vng O. Bi vy gc s l i din cho gc quay vng ca cc bnh xe dn hng cu trc. Mt khc AC v BD song song vi trc dc ca t. cc bnh xe khng b trt khi quay vng th mi quan h gia cc gc quay ca hai bnh xe dn hng phi m bo tha mn biu thc:

Trong :q : Khong cch gia hai ng tm tr ng ti v tr t cc cam quay ca cc bnh xe dn hng.L : Chiu di c s ca xe . : Gc quay vng bnh xe dn hng pha ngoi. : Gc quay vng bnh xe dn hng pha trong.R : Bn knh quay vng trung bnh ca xe.Ta c : q 1,04 (m) ; L 2,6 (m) ; R 5,3 (m) ,( theo ti liu thng s k thut ca xe ).

thun tin cho vic xc nh cc thng s ng hc ca xe,chng ta xt hnh bn di.

Hnh 14:S cc thnh phn ng hc quay vng ca xe.

Trong :R : Bn knh quay vng ca xe. : Gc quay vng bnh xe dn hng.T : Trng tm ca xe.v : Vn tc chuyn ng ca tm cu sau. : Bn knh quay vng ca trng tm T. : Vn tc gc quay vng quanh im O. : Gia tc gc ca xe khi quay vng quanh im O. : Gc to bi OT v OF ( F l tm cu sau ). : Gia tc hng tm ca trng tm T. : Gia tc hng theo trc dc xe ca trng tm T. : Gia tc hng theo trc ngang xe ca trng tm T.Bn knh quay vng (R) ca xe.

Vn tc gc ) ca xe khi quay vng c tnh:

Gia tc gc khi quay vng c xc nh:

T s hnh 14 ta c:

Thay cc gi tr t ( 5.2 ) v ( 5.5 ) vo ( 5.4 ) ta c:

Hai thnh phn gia tc ca trng tm T khi xe quay vng c xc nh nh sau:

Nh ta bit: ( 5.7 ) ln trc to dc v trc ngang ca xe , sau tng hp cc vc t gia tc thnh phn li , ta c:

Mt khc theo hnh 13 ta c:

Thay ( 5.3 ),( 5.4 ) v (5.10 ) vo (5.8 ) v ( 5.9 ) ta c :

NG LC HC QUAY VNG CA XE.

Xe c mt cu ch ng , quay vng trn ng c dc ( v vn tc khng phi hng s ( j, khi b qua bin dng ngang ca cc bnh xe, s ng lc hc quay vng quay vng ca xe c th hin trn hnh 14.

Hnh 15: S ng lc hc quay vng ca xe.

Trong : : Lc qun tnh ly tm tc dng ti trng tm T ca xe. : Hai thnh phn ca lc theo trc ngang ca xe. : Cc phn lc ngang tc dng di cc bnh xe. : Lc ko cc bnh xe ch ng. : Cc lc cn ln. : Lc cn ln dc. : Lc cn ca khng kh. : Mmen qun tnh tc dng ln xe xung quanh trc ng . xe quay vng n nh v khng b trt khi qu o cong ca ng th iu kin cn v l: Tng tt c cc lc tc dng ln xe theo chiu trc v phi bng khng, ng thi tng cc mmen tc dng ln xe xung quanh trc ng Tz i qua trng tm ca xe phi bng khng.Phng trnh cn bng lc theo chiu trc Tx:Xi = 0. Fk1.cos2 + Fk1.cos1 Fi F+FjlxFf1cos2 Ff1cos1Yb1sin2 Yb1sin1=0.Phng trnh cn bng lc theo chiu trc Ty:Yi=0. FjlyYb2Yb2Yb1cos2Yb1cos1+Fb1sin2+ Fb1sin1=0. Khi xe quay vng, lc qun tnh ly tm l lc ch yu lm cho xe chuyn ng khng n nh v l nguyn nhn chnh gy nn s nghing ngang ca xe v lm cho xe lt . Ta s tnh ln c th ca chng.Fjl =

Trong trng hp t chuyn ng u ( theo mt qu o ng trn th gc quay ca bnh xe dn hng s khng i = const ( Nn ta c:

Trong hai thnh phn Fji th thnh phn lc ngang Fjly l lc ch yu lm cho bnh xe ch ng khng n nh, l nguyn nhn chnh gy nn s nghing ngang ca xe v lm cho xe lt . Bi vy chng ta phi gim ti a gi tr Fjly khi t quay vng.V vy chng ta xc nh gi tr vn tc gii hn m xe c th b trt do thnh phn lc Fjly gy ra. n gin, xe c xt trong trng hp chuyn ng u ( , gc quay vng ca bnh xe dn hng khng i = const ( , cc thnh phn lc Ff1.sin2, Ff1.sin1 nh nn ta c th b qua.Phng trnh cn bng lc ko theo chiu trc Ty c vit li nh sau: Cu trc: Fjly1Yb1.cos2Yb1cos1=0 Cu sau : Fjly2Yb2Yb2=0Fjly1= Yb1.cos2+Yb1cos1= y.Z1Fjly2= Yb2+ Yb2= y.Z2 Trong :Fjly1: L thnh phn ngang ca lc qun tnh ly tm ti tm cu trc.Fjly2: L thnh phn ngang ca lc qun tnh ly tm ti tm cu sau. xe quay vng khng b trt ngang th:

Xt xe quay vng trn ng c h s bm ngang vi bn knh quay vng l 5,3m.Khi lc qun tnh ly tm theo chiu :

T hnh v ta c:

Lc qun tnh ly tm theo trc :

Lc qun tnh ly tm tng:

Thnh phn gia tc ngang ti trng tm theo chiu trc :

Thnh phn gia tc dc ti trng tm theo trc :

Vn tc nguy him vn ca xe khi vo ng c h s bm ngang 0,9

Hoc : /h ) Nu xe chuyn ng quay vng vi v vn th xe s b trt ngang. Tng t vi cc loi ng c h s bm ngang khc, ta cng xc nh c cc thng s ng hc v ng lc hc quay vng ca xe.

Bng 13: H s bm ngang v cc thng s ng lc hc quay vng ca xe TOYOTA ALTIS ng vi cc h s bm ngang y.

STTyFjly(N)Fjlx(N)Fjl(N)jy(m/jx(m/Vn(m/s)Vn(km/h)

10,9144453601,514887,292,2446,84124,627

20,8513642,53401,514060,18,52,1196,64823,933

30,8128403201,41323381,9956,44923,216

40,7512037,53001,3124067,51,8706,24422,478

50,7112352801,211578,971,7456,03321,719

60,6510432,52601,110751,96,51,6215,81320,927

70,6963024019924,861,4965,58520,106

80,558827,52200,99097,75,51,3715,34719,249

90,580252000,98270,751,2475,09818,353

100,457222,51800,87958,94,51,2124,83717,413

110,464201600,76616,540,9974,56016,416

120,355617,51400,65789,53,50,8734,26615,357

130,348151200,54962,430,7483,94914,216

140,254012,51000,44135,32,50,6233,60512,978

150,23210800,33308,320,4983,22511,61

Bng 14: Cc loi mt ng v vn tc ln nht m xe b trt ngang. TTLoi ngTnh trngH s bm yVn tc nguy him vn(km/h)

1ng b tng nha, b tng xi mng miKh0,80,923,21624,627

t0,60,720,106 23,216

2ng b tng nha, b tng xi mng mn schKh0,60,720,106 21,719

t0,450,5517,41319,249

3ng b tng nha, b tng xi mng c t bnKh0,50,618,35320,106

t0,40,516,41618,353

4ng lt

Kh0,550,819,24923,216

t0,40,516,41618,353

5ng ri

Kh0,550,7519,24922,478

t0,40,516,41618,353

6ng dm

Kh0,550,619,24920,106

t0,40,5516,41619,249

7ng t nn chtKh0,60,720,106 23,216

t0,40,516,41618,353

8ng t ct

Kh0,60,720,106 23,216

t0,70,823,21623,216

9ng t tnh trng xu( c bn ly)Kh0,250,412,97816,416

t0,20,2511,61 12,978

ngha s dng bng 14 trong thc t:Khi ngi ti x iu khin xe TOYOTA ALTIS quay vng trn cc loi ng c th c lit k bng 14. m bo xe vn chuyn ng n nh, khng b trt ngang th ngi li xe phi cho xe chuyn ng vi vn tc nh hn vn tc nguy him ( vn) c tnh cho tng loi ng c th.

TNH N NH NGANG CA XE KHI QUAY VNG TRN NG NGHING NGANG.

Trng hp 1: t quay vng trn ng nghing ngang ra ngoi ( trc quay vng khc pha vi hng nghing ngang ).

Theo iu kin lt :

Khi xe quay vng ngoi nhng lc ma xe phi chu nh trnh by cc phn trc. Ngoi ra khi xe quay vng trn ng cn chu tc dng ca lc ly tm F1 t ti trng tm ca xe ( trc quay vng l trc YY ). Lc F1 c phn tch thnh 2 phn do gc nghing ngang . Khi gc tng dn ng thi di tc dng ca lc F1 x b lt qua mt phng i qua A ( giao tuyn gia mt ng v mt phng thng gc qua trc bnh xe bn phi ng vi vn tc gii hn v hp lc Z = 0) coi Mjn=0.

Hnh 16:S lc v mmen khi xe quay vng trn ng nghing ngang ra ngoi .

Lp phng trnh mmen i vi im A:

Khi sp b lt Z =0, v thay gi tr vo thu gn ta c:

Theo iu kin trt bn:

F1.cos = Y+Y = y.(G.cos F1.sin)Thu gn ta c:

Trng hp 2: t quay vng trn ng nghing ngang vo trong( trc quay vng cng pha vi hng nghing ngang )

Hnh 17: S lc v m men khi xe quay vng trn ng nghing ngang vo trong. Theo iu kin lt :Lp phng trnh mmen i vi im A:

Khi xe sp b lt Z = 0, v thay gi tr v thu gn ta c :

Theo iu kin trt bn:

Fl.cos G.sin = Y+ Y = y.( G.cos+Fl.sin )Thu gn ta c:

Tnh ton theo iu kin lt ta c bng sau:dvn( nghing ra ngoi ) km/hvn( nghing vo trong) km/h

5056,1979,99

10047,0996,53

15039,16118,51

20032,09149,72

25025,66198,45

30019,69287,08

35014,06504,24

Khi y=0,9 ( ng b tng nha, b tng xi mng mi kh) tnh theo iu kin trt ta c bng sau:

v( nghing ra ngoi ) km/hv( nghing vo trong) km/h

504564,04

10037,3276,45

15030,4391,98

20024,13112,32

25018,25140,69

30012,68183,78

3507,32258,58

Khi y=0,7 ( ng b tng nha, b tng xi mng mn sch kh) tnh theo iu kin trt ta c bng sau:

v( nghing ra ngoi ) km/hv( nghing vo trong) km/h

5034,4950,13

10027,8659,74

15021,7471,20

2001685,32

25010,53103,47

3005,22128,11

Khi y=0,4 ( ng b tng nha, b tng xi mng c bn t t) tnh theo iu kin trt ta c bng sau:

v( nghing ra ngoi ) km/hv( nghing vo trong) km/h

5018,0430,19

10012,4837,05

1507,1244,71

2001,8853,43

Trng hp xe quay vng trn ng nm ngang.

Hnh 18: S lc v mmen tc dng ln t khi quay vng trn ng nm ngang.

Theo iu kin lt :

Lp phng trnh mmen i vi im A ta c:MiA = Z.c + Fl .hg = 0Khi xe sp b lt Z = 0 v thay gi tr

V thu gn ta c:

vn= 27,473 (km/h)

Theo iu kin trt bn ta c:

Fl = Y+Y = y . GThu gn ta c:

Khi xe chy trn cc loi ng khc nhau,tnh theo iu kin trt ta c bng sau:TTLoi ngTnh trngH s bm yVn tc ti hn m xe b trt v(km/h)

1ng b tng nha, b tng xi mng miKh0,80,923,21624,627

t0,60,720,106 23,216

2ng b tng nha, b tng xi mng mn schKh0,60,720,106 21,719

t0,450,5517,41319,249

3ng b tng nha, b tng xi mng c t bnKh0,50,618,35320,106

t0,40,516,41618,353

4ng lt

Kh0,550,819,24923,216

t0,40,516,41618,353

5ng ri

Kh0,550,7519,24922,478

t0,40,516,41618,353

6ng dm

Kh0,550,619,24920,106

t0,40,5516,41619,249

7ng t nn chtKh0,60,720,106 23,216

t0,40,516,41618,353

8ng t ct

Kh0,60,720,106 23,216

t0,70,823,21623,216

9ng t tnh trng xu( c bn ly)Kh0,250,412,97816,416

t0,20,2511,61 12,978

Nhn xt:

Qua phn tnh ton trn, ta c th thy gc gii hn v vn tc nguy him m ti t b lt hay b trt bn khi xe chuyn ng trn ng nghing ngang ph thuc vo ta trng tm, bn knh quay vng v h s bm ca xe vi ng.Ngoi ra xe chuyn ng cn mt n nh ngang do nh hng ca cc yu t nh lc gi ngang, do ng mp m v do phanh trn ng trn. Sau khi tnh ton ta thy vn tc rng vn tc nguy him khi trc nh hn vn tc nguy him khi lt cho thy xe m bo c iu kin an ton. xe chuyn ng an ton th phi chuyn ng vi vn tc.vmax