Are un efect franarea?

[flyer]

Deschid acest subiect in care vreau sa imi lamuresc eu un pitic pe care tocmai l-am incercat dar nu a fost asa cum ma asteptam eu.

Am ramas blocat pe o panta de 5 grade plina cu zapada in care ma afundam cand incercam sa ies. Am putut sa blochez si spatele ca tot degeaba.

De mult timp cand ma pun seara in pat ma gandesc la o varianta de a ajuta tractiunea in asemenea momente prin apasarea acceleratiei si a franei simultan. De ce zic asta? In mod normal cand accelerezi unde nu ai aderenta si rotile se invart in gol atunci apasand frana rotile tind sa se blocheze dar ABS-ul ar trebui sa impiedice acest lucru. In momentul cand franeaza o roata ar trebui sa se transmita moment si la cealalta roata de pe aceasi punte deci sa functioneze aproape ca un LSD. Problema ii ca ABS-ul se activeaza la viteze mai mari de 20kmph...deci ar trebui accelerata sanatos si apoi actionata frana. Eu ma gandesc la treaba asta deoarece si ESP-ul(NU ASR-ul) sau alte variante de control al tractiuni si corectarea traiectoriei functioneaza cam asemenator.

Oare are un efect pozitiv sau nu are cum sa te ajute defel?

[vstef_is]

Re: Are un efect franarea?

 

Ceva oarecum similar cu ce zici tu, e actionarea franei de mana... mai functioneaza cumva-necumva daca te joci cu ea putin, si cu gazul...

 

Totusi blocantu e blocant...

[flyer]

Re: Are un efect franarea?

 

Am putut sa blochez si spatele ca tot degeaba.

 

Ceva oarecum similar cu ce zici tu, e actionarea franei de mana... mai functioneaza cumva-necumva daca te joci cu ea putin, si cu gazul...

 

Totusi blocantu e blocant...

 

De data asta o putut fi el blocant ca tot nu m-a ajutat :(

[vstef_is]

Re: Are un efect franarea?

 

Pai ai trei diferentiale, plus cauciucuri. Aveai central blocat si spate blocat? Si ai ramas? Ce cauciucuri ai? Fata oricum e mai greu de blocat, pentru ca risti sa o rupi daca te cotesti prea tare.

[flyer]

Re: Are un efect franarea?

 

central si spate blocat

cauciucuri NOKIAN WR 245/70/16 noi .. adica de 3 luni

[Georgenis]

Re: Are un efect franarea?

 

Orice masina ai avea si cate diferentiale blocabile ai avea, tot se gaseste o situatie in care sa te impotmolesti. Fiecare masina are limitele ei, unele mai aproape altele mai extreme.

[Petre Niteanu aka bullbar]

Re: Are un efect franarea?

 

Cum ai iesit pana la urma?

[flyer]

Re: Are un efect franarea?

 

Am iesit ca m-au impins 3 indivizi si am facut si balans.

Incep sa cred ca mecanica pura ii depasita de electronica.

Chiar ma uitam la niste filme in care ditamai defenderul era subclasat de un discovery 3. Posibil ca din punct de vedere al fiabilitatii sa fe mai avantajoasa varianta mecanica dar uite ca si electronica evolueaza si va ajunge la un moment dat sa te poti baza pe ea.

 

Astea is filmele de care zic

[youtube:3ptlawuw]

[/youtube:3ptlawuw]____[youtube:3ptlawuw]

[/youtube:3ptlawuw]

[Make]

Re: Are un efect franarea?

 

Exact aceeasi senzatie am avut-o si eu cand am ramas impotmolit in nisip rau de tot. Pe unde am trecut cu masina cu greu si chinuita (e un Terrano 2) a venit cunostinta care m-a scos de acolo cu un Landcruiser nou si mergea ABSOLUT lejer pe unde se chinuia a mea. Deci clar electronica se pare ca a luat avant mare de tot. Dar si daca asta cade intr-un moment neplacut?

[Petre Niteanu aka bullbar]

Re: Are un efect franarea?

 

Aceste doua filmulete spun totul. Daca defenderul avea tractiune pe doua roti, una spate ... una fata, discovery-ul avea pe 3. Distributia electronica a tractiunii este un avantaj enorm...pentru femei! Nu offence! Asta una la mana, a doua fiind: abordarea. Daca ai sa te uiti atent, defenderul apuca cu roata spate stanga intr-un mic sant, ceea ce nu se intampla la discovery. Pe de alta parte...daca ai blocante....nu ai treaba, dar discovery-ul este o bijuterie. Adica nu este de offroad. Are numai butoane, tu nu faci nimic. Nici macar pedala de acceleratie nu iti mai functioneaza cum vrei tu daca apesi un anume buton. Asa ca...vor rog luati in considerare cam cum s-ar fi comportat o masina normala de teren cu blocant spate activat si fata blocata in mod similar. Nu cred ca acea rampa nu poate fi urcata de un Geu! Sau de o Toyota! In offroad totul tine de abordare. Daca discovery-ul poate urca incet (uitati-va la viteza abordata la urcare) nu la fel trebuie sa urci cu orice masina. Centrul de greutate, cauciucurile, suspensiile, distributia tractiunii sunt cateva chestii extrem de importante cand analizezi astfel de comparatii.

[marcel]

Re: Are un efect franarea?

 

Deschid acest subiect in care vreau sa imi lamuresc eu un pitic pe care tocmai l-am incercat dar nu a fost asa cum ma asteptam eu.

Am ramas blocat pe o panta de 5 grade plina cu zapada in care ma afundam cand incercam sa ies. Am putut sa blochez si spatele ca tot degeaba.

De mult timp cand ma pun seara in pat ma gandesc la o varianta de a ajuta tractiunea in asemenea momente prin apasarea acceleratiei si a franei simultan. De ce zic asta? In mod normal cand accelerezi unde nu ai aderenta si rotile se invart in gol atunci apasand frana rotile tind sa se blocheze dar ABS-ul ar trebui sa impiedice acest lucru. In momentul cand franeaza o roata ar trebui sa se transmita moment si la cealalta roata de pe aceasi punte deci sa functioneze aproape ca un LSD. Problema ii ca ABS-ul se activeaza la viteze mai mari de 20kmph...deci ar trebui accelerata sanatos si apoi actionata frana. Eu ma gandesc la treaba asta deoarece si ESP-ul(NU ASR-ul) sau alte variante de control al tractiuni si corectarea traiectoriei functioneaza cam asemenator.

Oare are un efect pozitiv sau nu are cum sa te ajute defel?

Interesant de testat. Depinde de modul in care este programat computatorul. Daca o duci in ture pina "depaseste 20km/h" si apoi apesi frina, masina va reactiona normal. Daca vei tine in continuare apasata si pedala de acceleratie, s-ar putea sa decupleze alimentarea automat, intrucit computatorul va primi doua informatii contrare. Poate stie cineva de la reprezentanta cum este programat compiterul si gaseste 5 minute libere sa te lamureasca. Daca nu stii pe nimeni acolo, pot sa-ti fac o intrare. Citeam pe forum, ca sunt masini la care ABS-ul este decuplat in momentul in care se selecteaza reductorul. Mai sunt altele la care il poti opri de la buton, tocmai din cauza faptului ca in teren greu incurca prin unele locuri. La tine cum e?

[flyer]

Re: Are un efect franarea?

 

Cu reductorul cuplat ABS-ul functioneaza. Se decupleaza automat cand ii blochez spatele.

Ce zici tu (invers invers :h5 ) ii posibil sa fie asa din cauza celor doua informatii trimise care se bat cap in cap.

Legat de service nu stiu ce sa zic ca pe aici prin cluj 99% sunt incompetenti ..... sau poate numai peste astia am dat eu cand am fost acolo.

[gabi pas]

Re: Are un efect franarea?

 

Daca ajungi pe 27 martie la Sibiu,sa ne spui si noua cate Range Rover (nu Discovery) sunt la start din 70 de masini...si nu ca n-ar fi bani pt achizitie...

[Alin]

Re: Are un efect franarea?

 

Din vagile mele cunostinte asupra masinilor stiu ca terano 2 are motor de 2800cc si toyota land cruiser 200 (toyota noua) 4700cc

http://www.toyota.com.au/landcruiser-200

Nu pare deloc iesit din comun ca toyota a trecut fara sa forteze pe acolo pe unde terrano se opintea din greu.

Daca gresesc va rog sa nu mi-o luati in nume de rau.Este doar o opinie personala.

[Guest]

Re: Are un efect franarea?

 

Poate te ajuta explicarea functionarii sistemului 4ETS de pe ML-ul meu. Toate cele 3 diferentiale sint "open" si le blocheaza computerul in functie de nevoi....lectura placuta:

 

Loss of traction & how ETS prevents spinning tires

 

 

If one of the four wheels loses traction, lets say the right rear, the rear differential senses this as less resistance and makes that wheel spin. A spinning wheel does not move the vehicle. The other wheel on the same axle (on firm ground with plenty of traction) gets the same amount of torque as the spinning wheel. Not much. Both wheels together do not produce enough torque to move the car. A differential always distributes torque equally. The amount of torque generated at the wheel with the least traction determines how much the other wheel will get - the same amount of very little. Little torque because traction is low at the spinning wheel.

 

If the vehicle is on absolutely level ground the two front wheels still have about equal traction (the advantage of 4WD) they receive equally high torque and move the vehicle.

 

Should the right rear wheel have lost traction due to a height difference, the left front wheel will also lose traction and spin even though the ground under the front axle is level. This diagonal wheel spin is very common.

 

This is valid for part time 4WD or full time 4WD with center differential locked.

 

If you have full time 4WD and your center differential is NOT locked, the center diff senses less resistance (traction) as well as the rear differential senses less traction (resistance) at one wheel - and makes that wheel spin. The center differential also always distributes torque equally. The amount of torque the axle with the least traction generates, determines how much the other axle will get - the same amount of very little. Little torque because traction is low. Most likely this amount of torque is not enough to move the vehicle. YOU ARE STUCK! see also ***

If the right rear AND the left front lose traction (this is the most common situation off-road where traction is usually lost on diagonally opposed wheels) your axle differentials distribute torque equally to left and right wheels. The amount of torque the wheels with the least traction generate determines how much the other wheels will get - the same amount of very little. Little torque because traction is low. The amount of torque that can be generated is dependent on the amount of traction (resistance).

So, the right rear and left front wheels are spinning.

 

YOU ARE STUCK!

 

This is valid for both part time 4WD and full time 4WD.

 

Limited slip differentials, the name says it all, they limit wheel slip.

 

They do not prevent wheel slip. They only limit wheel slip.

 

Traction is lost later than without limited slip. You will be stuck a little later. Traction will be lost when more torque is needed to move the car. Limited slip creates additional resistance and allows for a higher torque value to be produced at the wheel with less resistance.

 

Even though LS is a help in light duty situations, I think if you are serious about your options - go with real help (like 100% differential locks).

 

Fancy names like Trac-Loc are not differential locks - they are disguises for limited slip differentials. Also, be aware of false advertising by sales people.

 

Differential Lockers or diff locks are the only cure for the known shortcoming of differentials sometimes not distributing enough torque to the wheels as described above. Differential lockers and locking differentials are not the same. more...

(Only Dodge Powerwagon, Jeep Wrangler Rubicon and Mercedes-Benz G500 come standard with two diff locks).

 

Diff locks disable the differential's ability to sense resistance. By disabling (locking) the differential it is forced to make both wheels rotate at equal speeds - the amount of torque generated is now deteremined by each wheels's traction. The wheel with good traction will generate usually a lot of torque - most often enough to move the car.

 

DIFF LOCKS WILL KEEP YOU GOING! They will keep you from getting stuck.

 

BUT: Locking (disabling) the differential makes it impossible for wheels to roll at different speeds. Meaning, with lockers engaged on high traction surfaces you cannot make safe turns anymore, and on low traction surfaces turns will be very difficult.

 

This serious drawback of diff locks requires an educated driver who knows exactly when to lock the diff(s), usually only for a very brief moment, and when to unlock the diff to maintain steerability. Accidentally engaged diff locks on a paved winding mountain road can kill you! (Figure yourself why almost all manufacturers do not offer diff locks).

Aftermarket diff locks (ARB) are available for many makes and models of SUVs. They improve performance of any 4WD dramatically, and work as well as factory installed lockers (Mercedes/Dodge/Hummer/Jeep/Toyota/Mitsubishi) - but as I said, they belong only in hands of trained responsible drivers.

 

Diff locks will make the difference between STUCK and still DRIVING.

 

** Besides some Toyota (optional front & rear),Hummer (optional rear), Mitsubishi (optional rear) and Mercedes (Standard) most commercial and military 4WD vehicles have front and rear axle diff locks. The latest addition with 2 axle differential locks is the Jeep Wrangler "Rubicon".

Now the future of 4WD traction management, called 4ETS:

 

 

 

 

In Mercedes-Benz M-Class vehicles all differentials are "open", meaning no limited slip or diff lock is installed - saves money, saves weight. Plus: No negative effects on the steering. The ABS sensors of the M-Class are able to detect locking wheels as well as spinning wheels.

 

If the right rear wheels loses traction (remember this means less resistance for the diff), the rear differential makes the right rear spin. AFTER losing traction and spinning about 3mph faster than the opposing wheel the brake of the right rear wheel is activated - slowing it down to the speed of the other wheel. This braking action creates the SAME resistance as the traction at the other wheel. By creating equally high resistance with the brakes on the wheel with low traction the differential is then distributing equally high torque to both wheels.

 

In a way the rear differential is fooled to think both wheels have the same traction and now it will distribute an equal amount of high torque to each wheel, rather than sending little torque to both wheels.

 

The wheel with high traction will receive 50% of rear axle torque (25% of torque send from engine) and will transform it into moving action. The wheel with no traction, slowed down by the brake, receives the other 50% of rear axle torque which is transformed into heat.

Since the center differential (not visible like the axle diffs, it sits between the two driveshafts inside the transfer case) is also open (no locks, no limited slip, no viscous coupling), the front axle will receive very little torque from the moment the right rear wheel loses traction, because the center diff "thinks": "Less resistance in rear - So I'll reduce the torque to the front as well"

 

This means, the ML320 acts like a full time 4WD with an unlocked center diff for a split second until 4ETS steps in and keeps the vehicle moving.

 

If two wheels lose traction 4ETS slows down those two spinning wheels. Creating artificial traction (resistance). After the 4ETS action both diffs are fooled to think traction is equal on all four wheels, so they will send 25% of the available torque to each wheel. Transformed into moving action on the wheels with traction (resistance by ground friction / traction) - transformed into heat on the wheels with brake initiated resistance.

 

If three wheels lose traction, 4ETS will order three brakes to create resistance (brake friction) to fool the differentials.

 

The wheel with traction will receive its equal share of torque: 25%.

However, this might not be enough torque to move the car.

 

The other three wheels will receive their fair share of torque as well: 25% each. But the torque at these three wheels is transformed into heat instead of forward motion.

[Guest G55STEYR]

Re: Are un efect franarea?

 

PT bullbar "Aceste doua filmulete spun totul. Daca defenderul avea tractiune pe doua roti, una spate ... una fata, discovery-ul avea pe 3."

 

Io nu inteleg cum ati dedus asta: tractiune pe 2 roti sau 3. Pe masina scrie 4x4 permanent, ce nu e clar ? trag toate 4 permanent. Acuma ca nu se rotesc cu aceeasi viteza asta e pentru ca nu are blocante. Uita-te atent la descrierea functionarii sistemului 4-ETS care e dat de firma constructoare, cum zice ca diff oped da forta egala la roti dar daca una dispune de foarte putina aderenta va trage putin, si exact tot atata va trage si cea cu aderenta, adica tot putin.

Si electronica asta nu face decat sa simuleze aderenta, pt ca nu blocheaza efectiv diff. Ea simuleaza tractiunea mare la rotile care pierd aderenta. Sistemul functioneaza identic la orice marca, tractiune integrala, fata sau spate. Orice sistem de control al stabilitatii (ESP DSC PSA) are functia de control al tractiunii inclusa (ASR).

Performanta unui astfel de sistem este net inferioara blocantelor pentru ca se bazeaza pe pierderea aderentei, dupa care comanda o franare selectiva. Aceasta inseamna ca masina va pierde din viteza deci si din inertie, si din sansele de a trece. Cel mai bun exemplu sunt masinile de FORMULA OFFROAD sau TRACTORPULLING care merg blocat 100% 100% din timp.

[pinti]

Re: Are un efect franarea?

 

este un range rover nu un discovery corect dar sistemul de tractiune este identic la cele doua si surclaseaza modelul defender prin metoda de abordare a terenului

chiar cred ca este pe automat range roverul sau modul de coborare care nu necesita sa intervii la viteza sau turatii

[Guest Giobica]

Re: Are un efect franarea?

 

Aceste doua filmulete spun totul. Daca defenderul avea tractiune pe doua roti, una spate ... una fata, discovery-ul avea pe 3. Distributia electronica a tractiunii este un avantaj enorm...pentru femei! Nu offence! Asta una la mana, a doua fiind: abordarea. Daca ai sa te uiti atent, defenderul apuca cu roata spate stanga intr-un mic sant, ceea ce nu se intampla la discovery. Pe de alta parte...daca ai blocante....nu ai treaba, dar discovery-ul este o bijuterie. Adica nu este de offroad. Are numai butoane, tu nu faci nimic. Nici macar pedala de acceleratie nu iti mai functioneaza cum vrei tu daca apesi un anume buton. Asa ca...vor rog luati in considerare cam cum s-ar fi comportat o masina normala de teren cu blocant spate activat si fata blocata in mod similar. Nu cred ca acea rampa nu poate fi urcata de un Geu! Sau de o Toyota! In offroad totul tine de abordare. Daca discovery-ul poate urca incet (uitati-va la viteza abordata la urcare) nu la fel trebuie sa urci cu orice masina. Centrul de greutate, cauciucurile, suspensiile, distributia tractiunii sunt cateva chestii extrem de importante cand analizezi astfel de comparatii.

 

Mi se pare foarte competent acest post! :g

 

referitor la filme, cred ca este un Range Rover Sport si ca forma caroseriei este foarte importanta.

 

Defenderul in pozitia respectiva -vezi caroseria- are o apasare pe fata foarte redusa. Fara blocabil pe spate el ar trebui sa urce cu O SINGURA ROATA cea din dreapta spate. Forta de tractiune generata de o singura roata probabil nu e suficienta pentru inclinarea respectiva.

 

Singura sansa ar fi sa mentina aderenta pe ambele roti spate. Daca se inclina putin si pierde aderenta si pe una din rotile spate, la revedere, trebuie multa dibacie ca sa scapi fara daune.