1

1. PRORAUN VUNO BRZINSKIH KARAKTERISTIKA AUTOMOBILA

1.1. Spoljni otpori

1.1.1. Otpor pri kotrljanju (Rf)

,

gdje je: m = 1250 kg, ukupna masa vozila

f koeficijent otpora kotrljanju u funkciji brzine kretanja, a odreuje se empirijskom formulom , , usvojeno

f0 = 0.015 koeficijent otpora kotrljanja

v [km/h] brzina vozila

Izraunate vrijednosti date su u tabeli 1. i prikazane grafiki na slici 1Tabela 1.

v[km/h]102030405060708090100110120130140150

f0,0150,0150,0160,0160,0170,0170,0180,0190,0200,0220,0230,0250,0260,0280,030

Rf [N]150,03151,75155,41160,11166,16173,55182,29192,37203,80216,57230,68246,14262,94281,09300,58

.

1.1.2. Otpor vazduha (Rv)

EMBED Equation.3 , gdje je

K = 0.202 [Ns2/m4] koeficijent otpora vazduha

A = 2.14 m2 eona povrina vozila

v [km/h] brzina vozila

Izraunate vrijednosti date su u tabeli 2. i grafiki na slici 2.Tabela 2.v

[km/h]102030405060708090100110120130140150

Rv [N]3,3313,3029,9353,2083,13119,71162,94212,81269,34332,52402,35478,83561,96651,75748,18

1.1.3. Otpor uspona (Ru)

Ru = mg sin [N] , gdje je

Izraunate vrijednosti date su u tabeli 3. i grafiki na slici 3.Tabela 3.

P[%]48121620242832

sin 0,040,080,120,160,20,240,280,32

Ru [N]398,29796,571194,861593,141991,432389,722788,003186,29

1.1.4. Koeficijent ukupnog otpora puta (u)

u = f cos + sin

Dobijeni rezultati su prikazani u tabeli 4: Tabela 4

[%] []

42,2900,0150,9990,0390,054

84,5730,0150,9960,0790,094

126,8420,0150,9920,1190,134

169,0900,0150,9870,1570,172

2011,3090,0150,9800,1960,211

2413,4900,0150,9720,2330,248

2815,6400,0150,9620,2690,283

3217,7400,0150,9520,3040,318

1.2. Potrebna snaga za savlaivanje otpora

1.2.1. Potrebna snaga za savlaivanje otpora kotrljanja (Pf)

Izraunati podaci dati su u tabeli 5 i grafiki na slici 4:Tabela 5.

v km/h102030405060708090100110120130140150

Rf [N]150,0151,7155,4160,1166,1173,5182,2192,3203,8216,5230,6246,1262,9281,0300,5

Pf [kW]0,420,841,301,782,312,893,544,275,096,027,058,209,5010,9312,52

1.2.2. Potrebna snaga za savlaivanje otpora vazduha

Izraunati podaci dati su u tabeli 6 i grafiki na slici 5:

Tabela 6v km/h102030405060708090100110120130140150

Rv [N]3,3313,3029,9353,2083,13119,71162,94212,81269,34332,52402,35478,83561,96651,75748,18

Pv kW0,010,070,250,591,152,003,174,736,739,2412,2915,9620,2925,3531,17

1.2.3. Potrebna snaga za savlaivanje otpora uspona

v10,0020,0030,0040,0050,0060,0070,0080,0090,00100,00110,00120,00130,00140,00150,00

p4%1,112,213,324,435,536,647,748,859,9611,0612,1713,2814,3815,4916,60

p8%2,214,436,648,8511,0613,2815,4917,7019,9122,1324,3426,5528,7730,98

p12%3,326,649,9613,2816,6019,9123,2326,5529,8733,1936,5139,8343,15

p16%4,438,8513,2817,7022,1326,5530,9835,4039,8344,2548,6853,10

p20%5,5311,0616,6022,1327,6633,1938,7244,2549,7955,3260,85

p24%6,6413,2819,9126,5533,1939,8346,4753,1059,7466,38

p28%7,7415,4923,2330,9838,7246,4754,2161,9669,70

p32%8,8517,7026,5535,4044,2553,1061,9670,81

Tabela 7 1.3. Izbor karakteristika motora1.3.1. Dijagram zavisnosti snage na toku od brzine kretanja

gdje je:

Izraunati podaci dati su u tabeli 8 i grafiki na slici 7:Tabela 8

v102030405060708090100110120130140150

pf0,420,841,301,782,312,893,544,275,096,027,058,209,5010,9312,52

pv0,010,070,250,591,152,003,174,736,739,2412,2915,9620,2925,3531,17

Po0,430,921,542,373,464,896,719,0011,8315,2519,3424,1729,7936,2843,70

Pe0,471,021,722,633,855,437,4610,0013,1416,9521,4926,8533,1040,3148,55

Snaga pri maksimalnoj brzini kretanja vmax=150 km/h odreena je prethodnim izrazom, a usvaja se pretpostavka da je Pemax=Pe(vmax).1.3.2. Spoljna brzinska karakteristika motora

Spoljna brzinska karakteristika se odreuje eksperimentalno na probnom stolu ili je data od strane proizvoaa. Ako nam nije dostupna spoljna brzinska karakteristika ovim postupcima moemo pristupiti njenom odreivanju preko empirijskih obrazaca. Vrlo esto se koristi Lajdermanova formula:

Ako je poznata maksimalna snaga motora Pemax i ogovarajua ugaona brzina ePemax, tj samo jedna taka spoljne brzinske karakteristike to se kriva Pe = Pe(e) moe vrlo lako nacrtati prema prethodnom izrazu. Pe i e su snaga i ugaona brzina u traenoj taki brzinske karakteristike. Kako je ugaona brzina proporcionalna sa brzinom kretanja:

zavisnost Pe = Pe(v) moe da se odredi preko obrasca Lajdermana. Koeficijenti C1 i C2 odreeni su vrstom motora oto/dizel pomou Lajdermanovog obrasca uz uslove da je maksimalni obrtni moment Memax=98 [Nm], pri ne,Memax=3000 [o/min] i maksimalna snaga Pemax=48 [kW], pri ne,Pemax=6000 [o/min], te da je C1+C2=2.Odredimo prvo snagu potrebnu za dobijanje maksimalnog obtnog momenta:

[kW]Kako je izraz lajdermana moemo pisati kao:

Uvrtavanjem poznatih podataka dobijamo:

Rjeavanjem ovih jednaina dobijamo: C1=1,0648 i C2=0,9352.Zavisnost izmeu obrtnog momenta, snage i ugaone brzine odreena je izrazom:

[Nm]

iz proporcionalnosti broja obrtaja i brzine kretanja vozila imamo:

( , [/min].Dobijeni podaci Pe=Pe(v) i Me=Me(v) dati su u tabeli 9 i grafiki na slici 8.Tabela 9v, km/h102030405060708090100110120130140150

ne4008001200160020002400280032003600400044004800520056006000

ve/vmax0,070,130,200,270,330,400,470,530,600,670,730,800,870,931,00

Pe3,597,5011,615,920,224,528,732,736,439,842,645,046,747,748,0

Me85,789,592,594,996,697,798,097,796,795,092,689,685,881,476,4

1.4 Odreivanje prenosnog odnosa u glavnom prenosniku (i0)1.4.1. Izraunavanje prenosnog odnosa u glavnom prenosniku

Kako je uspostavljena veza izmeu ugaone brzine motora i brzine kretanja vozila time je odreen i prenosni odnos u glavnom prenosniku a preko izraza za maksimalnu brzinu: ,

( ,

.1.4.2. Analiza uticaja prenosnog odnosa glavnog prenosnika na vuno brzinske karakteristike

Analiziramo uticaj prenosnog odnosa (i0) za sluaj da su vrijednosti:

i0 = 3.5 ; 4 ; 4.915; 5.5; 6.

1.4.3. Analiza bilansa snage

,

;U tabeli 10 i na slici 9 date su krive snage na pogonskim tokovima u izabranom opsegu broja obrtaja koljenastog vratila, a u funkciji od brzina za razliite stepene prenosa:

[o/min]4008001200160020002400280032003600400044004800520056006000

[kW]3,236,7510,4714,3218,2222,1025,8729,4732,8135,8238,4240,5442,0943,0043,20

v [km/h]i01=3.513,9427,8941,8355,7769,7183,6697,60111,54125,49139,43153,37167,31181,26195,20209,14

i02=412,2024,4036,6048,8061,0073,2085,4097,60109,80122,00134,20146,40158,60170,80183,00

i03=4.9159,9319,8629,7939,7249,6459,5769,5079,4389,3699,29109,22119,15129,07139,00148,93

i04=5.58,8717,7526,6235,4944,3653,2462,1170,9879,8588,7397,60106,47115,35124,22133,09

io5=68,1316,2724,4032,5340,6748,8056,9365,0773,2081,3389,4797,60105,73113,87122,00

Tabela 10 1.4.4. Analiza prenosnog odnosa u glavnom prenosniku preko dijagrama vmax, Domax, amax, Fomax u zavisnosti od raznih vrijednosti io [km/h]

Izraunate vrijednosti date su u tabeli 11. Tabela 11:

3.544.9155.56

[km/h]210,64184,31150134,04122,87

[kN]

Izraunate vrijednosti date su u tabeli 12.

Tabela 12:

3.544.9155.56

[kN]0.9471.0821.331.481.62

Dinamika karakteristika:

Izraunate vrijednosti date su u tabeli 13.

Tabela 13:

3.544.9155.56

[km/h]105,3292,157567,0261,43

0,05810,08040,11480,13450,1505

[m/s2]

gdje je koeficijent rotirajuih masa koji nalazimo empirijskim obrascem:

, (

Izraunate vrijednosti date su u tabeli 14.

Tabela 14:

3.544.9155.56

[m/s2]0,39680,60170,91831,09941,2466

Zakljuak: Poveani prenosni odnosi smanjuju maksimalno mogue brzine kretanja vozila, izazivajui pri tom, zbog veeg broja obrtaja koljenastog vratila, poveano habanje klipnog mehanizma i trnsmisije. Motor pri vmax ima suvie veliku rezervu snage, a i ekonominost potronje goriva opada. Suvie mali prenosni odnos pomjera taku maksimalne snage u podruje velikih brzina koje se u toku eksploatacije nemogu postizati sa raspoloivom snagom. Dakle, jedan dio snage motora ostae neiskoriten jer e vozilo koristiti iskljuivo snage manje od maksimalne i tako dovesti do ne ekonominosti rada motora.

Izabrani prenosni odnos i0=4.915 je zadovoljavajui za zahtjevanu maksimalnu brzinu, a istim se obezbeuje i mala rezerva snage(slika 9 to i pokazuje).1.5. Dijagram vue

Vuni bilans (jednaina kretanja) automobila:

Izraunate vrijednosti date su u tabeli 15.

v [km/h]102030405060708090100110120130140150

Rf+Rv153,35165,05185,33213,31249,29293,26345,23405,19473,14549,09633,04724,97824,91932,841048,76

R,0153,35165,05185,33213,31249,29293,26345,23405,19473,14549,09633,04724,97824,91932,841048,76

R,4551,64563,33583,62611,60647,58691,55743,51803,47871,43947,381031,321123,261223,191331,121447,04

R,8949,93961,62981,911009,891045,861089,831141,801201,761269,711345,661429,611521,551621,481729,411845,33

R,121348,211359,911380,191408,171444,151488,121540,081600,041668,001743,951827,891919,832019,772127,692243,62

R,161746,501758,191778,481806,461842,431886,411938,371998,332066,292142,242226,182318,122418,052525,982641,90

R,202144,782156,482176,762204,742240,722284,692336,662396,622464,572540,522624,472716,402816,342924,273040,19

R,242543,072554,762575,052603,032639,012682,982734,942794,902862,862938,813022,753114,693214,623322,553438,47

R,282941,362953,052973,343001,323037,293081,263133,233193,193261,143337,093421,043512,983612,913720,843836,76

R,323339,643351,343371,623399,603435,583479,553531,513591,473659,433735,383819,323911,264011,204119,124235,05

Tabela 15 Za svaki broj obrtaja koljenastog vratila izraunavamo obimnu silu:

[N],

a brzine u pojedinim stepenima prenosa:

[km/h]

Izraunate vrijednosti date su u tabeli 16.Tabela 16

[o/min]4008001200160020002400280032003600400044004800520056006000

[Nm]85,7189,5192,5694,7296,6597,6998,0297,7196,6995,0292,6689,6185,8981,4876,40

[kW]3,236,7510,4714,2818,2222,1025,8729,4732,8135,8238,4240,5442,0943,0043,20

[kW]3,597,5011,6315,8720,2424,5528,7432,7436,4539,8042,6945,0446,7747,7848,00

[N]5843,366102,176309,976457,816588,846659,926682,786661,276592,106478,166316,876109,225855,895555,035208,57

[km/h]1,743,475,216,948,6810,4212,1513,8915,6217,3619,1020,8322,5724,3026,04

[N]3289,943435,653552,653635,893709,663749,683762,553750,443711,493647,343556,533439,623296,993127,602932,54

[km/h]3,086,179,2512,3415,4218,5021,5924,6727,7630,8433,9237,0140,0943,1846,26

[N]2031,612121,592193,842245,242290,802315,512323,462315,982291,932252,322196,242124,052035,971931,371810,91

[km/h]4,999,9814,9819,9724,9629,9534,9439,9444,9349,9254,9159,9064,9069,8974,88

[N]1551,891620,621675,811715,071749,871768,751774,821769,111750,741720,481677,641622,491555,211475,311383,30

[km/h]6,5213,0419,5626,0832,6039,1245,6452,1658,6865,2071,7278,2484,7691,2897,80

[N]1163,191214,701256,071285,501311,581325,731330,281326,001312,231289,551257,441216,111165,681105,791036,82

[km/h]8,7217,4426,1634,8843,6052,3261,0469,7678,4887,2095,92104,64113,36122,08130,80

[N]6086,616356,196572,646726,646863,126937,166960,976938,576866,516747,836579,836363,536099,655786,285425,39

[km/h]1,663,334,996,668,329,9811,6513,3114,9816,6418,3019,9721,6323,3024,96

1.6. Hiperbola vue

Hiperbola vue je odreena izrazom: [N]

Sraunate vrijednosti za T=0.90 i T=0.89 date su u tabeli 17, a krive vunog bilansa i hiperbola vue na slici 10.Tabela 17:

v km/h102030405060708090100110120130140150

Foh155527776518438883110,4025922221,71194417281555,201413,8212961196,311110,861036,80

Foh15379,207689,605126,403844,803075,842563,202197,031922,401708,801537,921398,111281,601183,021098,511025,28

1.7. Dinamika karakteristika

Dinamika karakteristika za pojedine stepene prenosa odreuje se kao:

Sraunate vrijednosti za date su u tabeli 18, a krive dinamike karakteristike za sve stepene prenosa na slici 11.

n [o/min]

i4008001200160020002400280032003600400044004800520056006000

iIFoI5843,366102,176309,976457,816588,846659,926682,786661,276592,106478,166316,876109,225855,895555,035208,57

vI1,743,475,216,948,6810,4212,1513,8915,6217,3619,1020,8322,5724,3026,04

RvI0,100,400,901,592,493,594,886,388,079,9712,0614,3516,8419,5322,42

DoI0,590,610,630,650,660,670,670,670,660,650,630,610,590,560,52

iIIFoII3289,943435,653552,653635,893709,663749,683762,553750,443711,493647,343556,533439,623296,993127,602932,54

vII3,086,179,2512,3415,4218,5021,5924,6727,7630,8433,9237,0140,0943,1846,26

RvII0,311,262,835,037,8611,3215,4120,1325,4831,4538,0582145,2953,1661,6570,77

DoII0,330,340,360,360,370,380,380,370,370,360,350,340,330,310,29

iIIIFoIII2031,612121,592193,842245,242290,802315,512323,462315,982291,932252,322196,242124,052035,971931,371810,91

vIII4,999,9814,9819,9724,9629,9534,9439,9444,9349,9254,9159,9064,9069,8974,88

RvIII0,823,307,4213,1920,6029,6740,3852,7466,7582,4199,72118,67139,27161,52185,42

DoIII0,200,210,220,220,230,230,230,230,220,220,210,200,190,180,16

iIVFoIV1551,891620,621675,811715,071749,871768,751774,821769,111750,741720,481677,641622,491555,211475,311383,30

vIV6,5213,0419,5626,0832,6039,1245,6452,1658,6865,2071,7278,2484,7691,2897,80

RvIV1,415,6212,6522,4935,1550,6168,8989,97113,87140,58170,10202,44237,58275,54316,31

DoIV0,160,160,170,170,170,170,170,170,160,160,150,140,130,120,11

iVFoV1163,191214,701256,071285,501311,581325,731330,281326,001312,231289,551257,441216,111165,681105,791036,82

vV8,7217,4426,1634,8843,6052,3261,0469,7678,4887,2095,92104,64113,36122,08130,80

RvV2,5110,0622,6340,2362,8690,53123,21160,93203,68251,46304,27362,10424,97492,86565,78

DoV0,120,120,120,130,130,120,120,120,110,100,100,090,070,060,05

Tabela 18:

1.8. Bilans snage automobila

1.8.1. Bilans snage na pogonskim tokovima Snaga na pogonskim tokovima

Za prvi stepen prenosa i hod unazad: [kW] Za ostale stepene prenosa: [kW] Brzina automobila: [km/h]

Izraunati podaci dati su u tabeli 19 i grafiki na slici 12:Tabela 19:

n [o/min]4008001200160020002400280032003600400044004800520056006000

Pe [kW]3,597,5011,6315,9120,2524,5528,7532,7536,4639,8042,6945,0446,7747,7848,00

Po(I) [kW]3,206,6810,3514,1618,0221,8525,5929,1532,4535,4237,9940,0941,6342,5242,72

Po [kW]3,236,7510,4714,3218,2322,1025,8829,4832,8135,8238,4240,5442,0943,0043,20

vI1,743,475,216,948,6810,4212,1513,8915,6217,3619,1020,8322,5724,3026,04

vII3,086,179,2512,3415,4218,5021,5924,6727,7630,8433,9237,0140,0943,1846,26

vIII4,999,9814,9819,9724,9629,9534,9439,9444,9349,9254,9159,9064,9069,8974,88

vIV6,5213,0419,5626,0832,6039,1245,6452,1658,6865,2071,7278,2484,7691,2897,80

vV8,7217,4426,1634,8843,652,3261,0469,7678,4887,295,92104,64113,36122,08130,8

1.8.2. Bilans vika snage Pod pojmom vika snage podrazumjevamo razliku: [kW],Izraunate vrijednosti date su u tabeli 20.Tabela 20:n [o/min]4008001200160020002400280032003600400044004800520056006000

PoI [kW]3,206,6810,3514,1618,0221,8525,5929,1532,4535,4237,9940,0941,6342,5242,72

Po [kW]3,236,7510,4714,3218,2322,1025,8829,4832,8135,8238,4240,5442,0943,0043,20

vI1,743,475,216,948,6810,4212,1513,8915,6217,3619,1020,8322,5724,3026,04

PfI [kW]0,070,140,220,290,360,430,510,580,650,730,800,880,961,031,11

PvI [kW]0,000,000,000,000,010,010,020,020,040,050,060,080,110,130,16

PI3,126,5310,1313,8717,6621,4125,0628,5431,7634,6537,1339,1240,5641,3641,45

vII3,086,179,2512,3415,4218,5021,5924,6727,7630,8433,9237,0140,0943,1846,26

PfII [kW]0,130,260,380,510,650,780,911,051,191,331,481,631,781,942,10

PvII [kW]0,000,000,010,020,030,060,090,140,200,270,360,470,590,740,91

PII3,106,4910,0813,7917,5521,2624,8728,2931,4334,2236,5938,4439,7240,3340,19

vIII4,999,9814,9819,9724,9629,9534,9439,9444,9349,9254,9159,9064,9069,8974,88

PfIII [kW]0,210,420,630,841,061,291,531,772,032,302,582,883,203,533,88

PvIII [kW]0,000,010,030,070,140,250,390,590,831,141,521,972,513,143,86

PIII3,026,339,8113,4017,0220,5623,9627,1229,9532,3834,3235,6836,3936,3435,46

vIV6,5213,0419,5626,0832,6039,1245,6452,1658,6865,2071,7278,2484,7691,2897,80

PfIV [kW]0,270,540,821,111,411,732,072,422,813,223,664,134,645,205,79

PvIV [kW]0,000,020,070,160,320,550,871,301,862,553,394,405,596,998,59

PIV2,966,199,5713,0416,4919,8122,9425,7528,1530,0631,3832,0031,8630,8228,82

vV8,7217,4426,1634,8843,652,3261,0469,7678,4887,295,92104,64113,36122,08130,8

PfV [kW]0,360,731,121,521,962,432,953,524,154,855,626,477,418,449,58

PvV [kW]0,010,050,160,390,761,322,093,124,446,098,1110,5313,3816,7120,56

PV2,865,979,1912,4115,5018,3520,8422,8424,2224,8824,7023,5421,3017,8413,06

1.8.3. Bilans slobodne snage Slobodna snaga podrazumjeva razliku snage na pogonskim tokovima i angaovane snage za savlaivanje otpora vazduha pri odreenoj brzini kretanja vozila [kW].Izraunati podaci dati su u tabeli 21 i grafiki na slici 14 Tabela 21:PosI3,206,6710,3514,1618,0221,8425,5729,1232,4135,3737,9340,0041,5242,3942,56

PosII3,196,6710,3414,1417,9921,7925,5029,0132,2535,1537,6439,6241,0341,7841,81

PosIII3,196,6710,3214,0917,8821,6025,2028,5631,6234,2836,4738,1139,1139,3938,86

PosIV3,196,6510,2814,0017,7021,3024,7127,8430,5932,8834,6135,6936,0335,5434,13

PosV3,196,6310,1913,7717,2620,5323,5026,0328,0129,3329,8929,5628,2425,8122,16

1.9. Mogunost savlaivanja uspona u pojedinim stepenima prenosa Usponi u pojedinim stepenima prenosa se odreuju po formuli:

Izraunate vrijednosti su date u tabeli 21:Tabela 21:

[o/min]4008001200160020002400280032003600400044004800520056006000

0,590,610,630,650,660,670,670,670,660,650,630,610,590,560,52

0,570,600,620,640,650,660,660,660,650,640,620,600,570,540,51

0,330,340,360,360,370,380,380,370,370,360,350,340,330,310,29

0,320,330,340,350,360,360,360,360,360,350,340,330,310,290,27

0,200,210,220,220,230,230,230,230,230,220,220,210,200,190,17

0,190,200,210,210,210,220,220,220,210,210,200,190,180,170,16

0,160,160,170,170,170,170,170,170,160,160,150,140,130,120,11

0,140,150,150,160,160,160,160,150,150,140,140,130,120,110,09

0,120,120,120,130,130,120,120,120,110,100,100,090,070,060,05

0,100,110,110,110,110,110,110,100,100,090,080,070,060,050,03

1.10 Ubrzanje vozila Ubrzanje motornih vozila u pojedinim stepenima prenosa odreeno je formulom:

1.10.1. Koeficijent uticaja rotirajuih masa

gdje je:

ii prenosni odnos u mjenjakom prenosniku u pojedinim stepenima prenosa,

1 koeficijent obrtnih masa motora

2 koeficijent uticaja obrtnih masa pogonskog mosta

Na osnovu preporuka za ove koficijente (, )usvaja se 1=0.03 i 2=0.03, pa je koeficijent uticaja rotirajuih masa odreen kao

Izraunate vrijednosti su date u tabeli 23. Tabela 23ii4,3002,4211,4951,1420,8564,300

i1,5851,2061,0971,0691,0521,585

i/g0,1620,1230,1120,1090,1070,162

1.10.2. Ukupni otpor puta

Ukupni otpor puta odreen je izrazom: , a za specijalan sluaj kretanja po horizontalnom putu u = f .

Izraunate vrijednsti date su u tabeli 24, a zavisnost ubrzanja od kretanja vozila za sve stepene prenosa na slici 15.

Tabela 24:iI[km/h]1,743,475,216,948,6810,4212,1513,8915,6217,3619,1020,8322,5724,3026,04

0,590,610,630,650,660,670,670,670,660,650,630,610,590,560,52

[m/s2]3,533,693,823,913,994,034,054,033,993,923,823,693,533,343,12

iII[km/h]3,086,179,2512,3415,4218,5021,5924,6727,7630,8433,9237,0140,0943,1846,26

0,330,340,360,360,370,380,380,370,370,360,350,340,330,310,29

[m/s2]2,562,682,782,842,902,932,942,922,892,832,752,652,532,382,21

iIII[km/h]4,999,9814,9819,9724,9629,9534,9439,9444,9349,9254,9159,9064,9069,8974,88

0,200,210,220,220,230,230,230,230,230,220,220,210,200,190,17

[m/s2]1,721,801,861,911,951,971,971,961,931,891,831,761,671,571,45

iIV[km/h]6,5213,0419,5626,0832,6039,1245,6452,1658,6865,2071,7278,2484,7691,2897,80

0,160,160,170,170,170,170,170,170,160,160,150,140,130,120,11

[m/s2]1,291,351,391,421,441,451,431,411,371,321,251,171,080,970,85

iV[km/h]8,7217,4426,1634,8843,6052,3261,0469,7678,4887,2095,92104,64113,36122,08130,80

0,120,120,120,130,130,120,120,120,110,100,100,090,070,060,05

[m/s2]0,950,991,021,031,031,020,990,950,900,830,750,660,560,440,30

1.10.3. Odreivanje vremena ubrzanja

U cilju odreivanja integrala grafikom metodom nacrtaemo grafik funkcije 1/a u funkciji brzine v, pri emu e povrina ispod krive predstavljati traeno vrijeme t (krive 1/a za razliite stepene prenosa emo spojiti tako da nam povrina bude sa gornje strane ograniena jednom krivom.

Vrijednosti funkcije 1/a date su u tabeli 25 a grafik na slici 16.

Tabela 25

iI

[km/h]1,743,475,216,948,6810,4212,1513,8915,6217,3619,1020,8322,5724,3026,04

1/a10,280,270,260,260,250,250,250,250,250,260,260,270,280,300,32

iII

[km/h]3,086,179,2512,3415,4218,5021,5924,6727,7630,8433,9237,0140,0943,1846,26

1/a20,390,370,360,350,340,340,340,340,350,350,360,380,400,420,45

iIII

[km/h]4,999,9814,9819,9724,9629,9534,9439,9444,9349,9254,9159,9064,9069,8974,88

1/a30,580,560,540,520,510,510,510,510,520,530,550,570,600,640,69

iIV

[km/h]6,5213,0419,5626,0832,6039,1245,6452,1658,6865,2071,7278,2484,7691,2897,80

1/a40,770,740,720,700,690,690,700,710,730,760,800,850,931,031,18

iV

[km/h]8,7217,4426,1634,8843,6052,3261,0469,7678,4887,2095,92104,6113,3122,0130,8

1/a51,051,010,980,970,970,981,011,051,111,201,331,511,802,303,31

2. OPTI PARAMETRI KOENJA2.1. Zavisnost vertikalnih reakcija tla i sila koenja na prednjoj i zadnjoj osovini od koeficijenta prijanjanja

Vertikalne reakcije tla su odreene kao:

[kN] i [kN],

a sile koenja: [kN], [kN].

Izraunate vrijednosti su date u tabeli 26, a grafiki prikaz je na slici 17.Tabela 26:

0,10,20,30,40,50,60,70,80,9

Z15,7816,0476,3126,5776,8427,1087,3737,6387,903

Z24,1763,9103,6453,3803,1152,8492,5842,3192,054

K10,5781,2091,8942,6313,4214,2655,1616,1117,113

K20,4180,7821,0941,3521,5571,7101,8091,8551,848

2.2. Zavisnost koficijenta raspodjele koionih sila od koficijenta prianjanja i visine teita hT

Na osnovu slijedi tabela 27 i slika 18. Tabela 27:hT / l0,10,20,26

= 0.30,580,610,628

= 0.50,60,650,68

= 0.70,620,690,732

2.3. Odreivanje teorijske duine puta koenja

2.3.1. Koenje samo zadnjim tokovima

Uzimajui da se koenje vri do potpunog zaustavljanja na suhom putu pri emu je >>f, te ako f zanemarimo, duin puta moemo izraunati kao:

[m].

Izraunate vrijednosti su date u tabeli 28 i grafiki na slici 19Tabela 28: v km/h

102030405060708090100110120130140150

= 0.3Sk23,1512,5828,3250,3478,65113,26154,16201,36254,84314,62380,69453,05531,71616,66707,89

= 0.5Sk21,987,9217,8231,6949,5171,3097,05126,75160,42198,05239,64285,20334,71388,18445,62

= 0.7Sk21,485,9113,3123,6636,9753,2372,4694,64119,78147,87178,92212,93249,90289,83332,71

2.3.2. Koenje samo prednjim tokovima

Izraunate vrijednosti su date u tabeli 29 i grafiki na slici 19.

Tabela 29:

v km/h

102030405060708090100110120130140150

= 0.3Sk22,6810,7124,1042,8566,9696,42131,23171,41216,94267,83324,07385,67452,63524,94602,61

= 0.5Sk21,516,0613,6324,2337,8554,5174,1996,90122,65151,41183,21218,04255,89296,77340,68

= 0.7Sk21,014,069,1316,2325,3736,5349,7264,9482,19101,47122,78146,11171,48198,88228,30

2.3.3. Koenje svim tokovima

U ovom sluaju imamo: [m]

Izraunate vrijednosti su date u tabeli 30 i grafiki na slici 19

Tabela 30:

v km/h

102030405060708090100110120130140150

= 0.3Sk21,315,2411,8020,9832,7747,1964,2483,90106,19131,09158,62188,78221,55256,94294,96

= 0.5Sk20,793,157,0812,5919,6628,3238,5450,3463,7178,6695,17113,27132,93154,17176,98

= 0.7Sk20,562,255,068,9914,0520,2327,5335,9645,5156,1867,9880,9094,95110,12126,41

3. OCJENA STABILNOSTI VOZILA

3.1. Uzduna stabilnost3.1.1. Odreivanje ugla nagiba vozila pri kome moe doi do prevrtanja oko zadnje osovine

sl. 20. ema sila koje djeluju na vozilo pri njegovom kretanju na usponu

Sa slike 19 je evidentno da prevrtanje nastaje pri , a proklizavanje za

Moemo zakljuiti da e prije natupiti proklizavanje jer je: