 Sisteme AWD, care e cel mai bun? |
Vrem opinia ta!
Masini.ro a inceput sa construiasca cea mai mare baza de date auto, cladita pe marginea si cu ajutorul opiniilor utilizatorilor si proprietarilor de automobile.
Ai o masina, ai avut una, sau mai multe? Esti cunoscator auto?
Scrie-ti opinia despre masina ta si despre masinile pe care le cunosti. Ajuta-ne sa facem cunoscute masinile asa cum sunt ele de fapt, nu in baza reclamelor producatorilor sau dealerilor auto! Da-i o nota generala masinii tale! O opinie pertinenta si motivata face cat 10 reclame!
Opinia ta conteaza
Masini.ro a inceput sa construiasca cea mai mare baza de date auto, cladita pe marginea si cu ajutorul opiniilor utilizatorilor si proprietarilor de automobile.
Ai o masina, ai avut una, sau mai multe? Esti cunoscator auto?
Scrie-ti opinia despre masina ta si despre masinile pe care le cunosti. Ajuta-ne sa facem cunoscute masinile asa cum sunt ele de fapt, nu in baza reclamelor producatorilor sau dealerilor auto! Da-i o nota generala masinii tale! O opinie pertinenta si motivata face cat 10 reclame!
Opinia ta conteaza
Sisteme AWD, care e cel mai bun?
This topic is about Sisteme AWD, care e cel mai bun?, the author, Valentin50014, wrote about: LSD-urile nu sunt diferentiale autoblocabile in adevaratul sens al cuvantului. Marketingul le-a facut asa. Este explicat in unul din linkurile mele. N ... To read more just scroll down
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 Nov 21 2005, 12:02 AM
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#61
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 specialist  Group: Membri Posts: 584 Joined: 28-June 05 From: Bucuresti Member No.: 50.007  |
Nu exista nici o masina FWD la VAG cu torsen, asa ca nu pot fi comparate. TT-ul foloseste Haldex -------------------- Audi A4 130CP - 2002
Panda MultiJet 1,3 |
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Nov 21 2005, 12:18 AM
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#62
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 specialist Group: Membri Posts: 4.583 Joined: 30-May 04 From: Honda World Member No.: 26.577 |
ma refeream strict la eficienta unui LSD fata de un diferential deschis. parerea mea ca nu exista nici un dubiu la FWD LSD is much better that open differential of any kind (+/- EDL).
diferenta de care vorbeam la demaraj devine si mai proeminenta pe circuit ( un helical LSD trasmite mult mai eficient cuplul la roata exterioara permitand viteze mai mari la iesirea din curbe). diferentialele blocabile nu sunt utile decat la off-roadere. pe sosea nu ai nevoie si e chiar daunator sa invarti toate rotile cu aceeasi viteza in acelasi timp. terminologia in engleza este mai corecta: "diferential cu patinare limitata" nu "autoblocabil". -------------------- Civic Si 2007 2.0l DOHC iVTEC
Acura TL 2006 3.2l SOHC VTEC |
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Nov 21 2005, 12:29 AM
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#63
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specialist Group: Membri Posts: 584 Joined: 28-June 05 From: Bucuresti Member No.: 50.007 |
Am inteles acum. Eu nu sunt asa sigur. LSD-urile cu VC sunt mai lente in functionare (roata trebuie sa patineze). In cazul electronicii (torsen precum si Haldex - desi nu e cu adevarat permanent AWD) viteza de reactie este mult mai mare. Blocarea nu se realizeaza neaprat total (depinde in ce masura pierde cuplul). Si la quattro cuplul este transferat in exterior, este foarte usor. Mai este un mare avantaj: se poate upgrada software foarte usor...
La performantele masinii contribuie multi factori, e greu sa facem o comparatie intre AWD in functie de timpii de pe circuit -------------------- Audi A4 130CP - 2002
Panda MultiJet 1,3 |
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Nov 21 2005, 12:38 AM
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#64
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specialist Group: Membri Posts: 4.583 Joined: 30-May 04 From: Honda World Member No.: 26.577 |
QUOTE Comparison with other types of differentials
Primul exemplu de diferential de pe Subaru, postat de f1anatic Other means are also known for modifying the operative connection between drive axles to provide for the transfer of additional torque to the drive axles collectively. For example, many limited-slip differentials provide for preloading friction clutches to oppose the transfer of torque between drive axles. This frictional pre-load represents a particular minimum magnitude of resistance which must be overcome to permit any relative rotation between drive axles which may interfere with the operation of anti-lock braking systems. Also, since frictional forces are continually active to resist differentiation, the friction clutches tend to wear, resulting in a deterioration of intended differential performance. da, dar aici e vorba de diferentialul central... In contrast to the limited-slip's continuous magnitude of frictional resistance to differentiation, the torque biasing characteristic of the Torsen differential provides for a maximum ratio of torque distributions between drive axles. For instance, as the amount of torque being conveyed by the Torsen differential decreases, the amount of resistance to differentiation also decreases. That is, even though the bias ratio remains relatively constant, a proportional division of a lower magnitude of torque being conveyed by the differential results in a smaller torque difference between drive axles. In braking situations where little or no torque is being conveyed by the differential, a four to one apportionment of torque between drive axles amounts to little or no torque difference between drive axles. Thus, the Torsen differential will not support any appreciable torque 'wind-up' between drive axles during braking and so does not interfere with the operation of anti-lock braking systems. Al doilea tip de diferential LSD de pe Subaru, din nou Torsen este mai performant Another known approach to modifying the operative connection between drive axles is to provide for resisting differentiation as a function of the speed difference between drive axles. It has long been appreciated that undesirable wheel slip is associated with very high rates of differentiation. Differentials have been designed using fluid shear friction, which respond to increased rates of differentiation by increasing fluid shear frictional resistance to differentiation. The obvious problem with such 'speed sensitive' differentials is that undesirable wheel slip has already occurred well in advance of its detection. Also, the fluid shear friction designs generally rely on the changes in fluid temperature associated with high differential shear rates to increase resistance to differentiation. However, similar temperature changes may be associated with extended periods of desirable differentiation, or may be influenced by changes in ambient temperature, so that resistance to differentiation may vary throughout ordinary conditions of vehicle use. The bias ratio characteristic of the Torsen differential instantly reacts to unequal traction conditions by delivering an increased amount of torque to the drive wheel having better traction before the other drive wheel exceeds the limit of traction available to that wheel. The bias ratio characteristic also remains substantially constant over a wide range of torque conveyed by the differential, and is not sensitive to changes in ambient temperature or conditions of vehicle use. inteleg ca exista avantaje ale Torsen fata de vascocuplaj. nu am avut dubii despre asta. ceea ce deplang la quattro este ca lipsesc LSD pe fiecare punte. si nu inteleg cum cu Torsen poti trimite 100% din cuplu pe una din roti cand esti limitat de ratia respectiva 66/34? nu mi-e clar ce diferentiale are RS4 sau S4 dar A4 quattro mi se pare sub Legacy GT ori STI. oricum dincolo de teorie e nevoie de un test pe un circuit cu zone cu nisip si/sau gheata in care sa vezi cat de stabila si cat de rapida fiecare dintre cele doua este. de fapt in unul din topicurile deschise anul trecut era vorba depre Legacy Outback vs. Passat B5 4 motion ( cu Torsen). concluzia mea atunci (dupa discutia cu George si ce am gasit atunci pe internet despre asta) a fost ca desi Passat avea avantajul Torsen Legacy( chiar cel vechi pt. ca schimbarea de generatie la Legacy a fost in 2004) -------------------- Civic Si 2007 2.0l DOHC iVTEC
Acura TL 2006 3.2l SOHC VTEC |
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Nov 21 2005, 08:01 AM
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#65
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 Subaru Anti-Hero Group: Moderator Posts: 5.323 Joined: 13-May 04 From: F 1 World Member No.: 25.368 |
QUOTE(Valentin50014) Am inteles acum. Eu nu sunt asa sigur. LSD-urile cu VC sunt mai lente in functionare (roata trebuie sa patineze). In cazul electronicii (torsen precum si Haldex - desi nu e cu adevarat permanent AWD) viteza de reactie este mult mai mare. Blocarea nu se realizeaza neaprat total (depinde in ce masura pierde cuplul). Si la quattro cuplul este transferat in exterior, este foarte usor. Mai este un mare avantaj: se poate upgrada software foarte usor...
La performantele masinii contribuie multi factori, e greu sa facem o comparatie intre AWD in functie de timpii de pe circuit Ce inseamna la tine viteza de reactzie cu mult mai mare ? La Subaru ii ia minute si la AUDI 0.01 secunde ? Cred ca supraestimezi calitatzile de la AUDI. Sincer...daca tu crezi ca electronica ofera raspuns la tot...E usor sa aduci un upgrade la soft. He he he...pe de alta parte la viscocuplaj nu ai ce upgrade sa aduci. Ori merge cum trebuie...ori nu. E un design mai simplu...dar poate mai eficient. Cred ca gasesti avantajos sa prajesti frinele in incercarea de a avea pseudo tractziune. ? SI am observat ca incerci sa lansezi ideea cum ca la AUDI sistemul ar fi pro-active in loc de retro-active. Din cite m-am prins eu pina acum...toata electronica aia este tot retro-active...Singurul sistem pro-active AWD este pe Acura RL SH-AWD care nu stiu daca are diferentziale autoblocabile. Oricum, tractorul ala care ma va scoate pe mine din namete (pina ajungem sa ii scoatem pe baietzii cu AUDI)...are tot diferentziale mecanice LSD. Fie el Universal U-65 sau John Deer sau Caterpillar. Legacy a fost votata cu sistemul AWD cel mai performant pentru 2005 de catre Edmunds.com. Acum website-ul nu vrea sa se deschida... http://www.edmunds.com/reviews/list/top10/...66/article.html -------------------- Schumi drive it like you stole it !
2005 Subaru Legacy GT ; 2009 Subaru Forester XP ; 2014 Jeep Grand Cherokee |
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Nov 21 2005, 03:10 PM
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#66
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perioada de proba Group: Membri Posts: 5 Joined: 2-October 05 From: Constanta (Constanta) Member No.: 57.308 |
Va recomand acest link http://www.germancarfans.com/news.cfm/newsid/2050714.001
Si da este pro-active. |
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Nov 21 2005, 04:47 PM
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#67
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Subaru Anti-Hero Group: Moderator Posts: 5.323 Joined: 13-May 04 From: F 1 World Member No.: 25.368 |
QUOTE(Mihnea57315) Va recomand acest link http://www.germancarfans.com/news.cfm/newsid/2050714.001
Si da este pro-active. Link-ul imi place...cu toate ca as putea face talente...ca vezi doamne...ghici unde era aceasta informatzie...pe un forum al GERMAN CAR FANS. Dar nu este PRO-ACTIVE QUOTE With BMW xDrive reacting within fractions of a second, the system offers enormous advantages also in terms of traction. When setting out on slippery or loose ground, for example, the time-lag between the loss of wheel grip on the surface and the re-distribution of drive forces to wheels with grip is only a few milliseconds.
O alta chestie care ma face circumspect este acest "few milliseconds". Ultima data cind am verificat...ii lua unei masini de Formula Unu sa schimbe o treapta de viteza circa 170 milliseconds. Formula Unu...cu tehnologie actuala nu de acum 15 ani. Asa ca...nu prea cred in redistribuirea puterii "in only a few milliseconds". O fi mai iute ca la Subaru cu cutie manuala (ca Subaru cu cutie auto cu VTD este mult mai dependenta de senzori si electromagnetzi) dar nici in citeva millisecunde nu poate schimba. Citind mai departe...nu reusesc sa gasesc nimic despre transferul stinga-dreapta al puterii. Ei spun ca sint senzori care detecteaza anumitzi parametri ...inainte de "wheel-spin" ceea ce potzi spune ca e pro-active...dar potzi spune ca este si "early detection". Comparind-o cu Acura, la RL pe uscat in curba...cuplul este mutat la rotata pe spate din exteriorul curbei...pt. a ajuta la tractziune. No wheel spin In continuare vad ca cu cit devin mai sofisticate aceste AWD, in general dispare cutia de viteza manuala si LSD-urile. Uite sumarul lor. (pagina 5) QUOTE BMW xDrive distributes drive power infinitely and fully variably between the front and rear axle. The system immediately recognises the need to change the distribution of engine power and responds extremely quickly, usually before a wheel even loses grip when driving onroad. As a result, xDrive feeds exactly the right drive power to each axle when, for example, taking a bend fast and dynamically, in the process significantly reducing both under- and oversteer.
The electronically controlled multiple-plate clutch in the power divider controls the flow of power to the front axle within milliseconds as a function of individual requirements. In extreme cases the front and rear axles are even fully disconnected from one another or rigidly, firmly connected to form one unit. Oh wow...axele sint deconectate una de alta...adica no traction...adica soferul devine pasager...la mila computerului. Asta...sincer mi-a zbirlit parul pe spate...de ajunsesem un arici Intervening electronically in the brakes, DSC provides the same function as a transverse wheel lock with forced distribution of power to the front and rear wheels: As soon as a wheel starts to spin without conveying power, the brakes cut in to slow the wheel down, the differential in the final drive thus feeding more power to the opposite wheel. EXEMPLU ! Ok si prima referintza la transfer lateral. Pai...tot la parerea initziala ca da...e avansat...citeste situatzia drumului mai repede si poate face ajustari mai repede...dar treaba asta cu pseudo - traction iar ma agita. Pai ma scuzi...asta nu este transfer lateral adevarat...Pur si simplu...daca creierul masinii a decis ca puntea fatza are nevoie de 30% ...iar puntea spate 70%...atunci daca roata dreapta spate dintr-o data pierde tractziunea...inseamna ca frina dreapta spate o frineaza...si deci contributzia ei de 35% (jumatate din 70% cuplu dedicat puntzii spate) este pierdut in neant...iar masina opereaza pe stinga fatza 15% dreapta fatza 15% stinga spate 35% dreapta spate 0% (frinata) Pai I am sorry...dar la Subaru pot trimite pina la 100% la oricare 2 rotzi. Diferentzialul pe fatza la Legacy este deschis (la fel ca la Audi, BMW) deci orice primeste puntea fatza se imparte fratzeste pe din 2. Dar in situatzia precizata mai sus...asa...incet cum este...ca doar masina saracului nu poate reactziona in a few milliseconds...ci in citeva minute....tot cuplul este transferat la roata ailalta. Dupa care sistemul tinde din nou spre 50%-50% fatza spate. stinga fatza 15% dreapta fatza 15% stinga spate 70% dreapta spate 0% (nefrinata, dar fara cuplu) Iar daca amestecam si STi-ul in povestea asta...cu diferential LSD si pe fatza...cu DCCD (driver controlled center differential - electronic by the way, sau automat de creierul masinii)...pot spune ca puterea poate fi trimisa 100% la o singura roata. Asa...cu tot visco-cuplajul asta antic de pe vremea lui Fuji-san si a fiului sau Subarumoto. Pe sosea uscata sau cu ceva ploaie ...as prefera BMW...pt ca fara LSD (centru, spate), pierderile prin transmisie sint mai mici. Dar cind e vorba de business adevarat cu zapada si ploaie serioasa...cred ca imi prefer masina de om de rind. -------------------- Schumi drive it like you stole it !
2005 Subaru Legacy GT ; 2009 Subaru Forester XP ; 2014 Jeep Grand Cherokee |
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Nov 21 2005, 04:58 PM
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#68
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specialist Group: Membri Posts: 584 Joined: 28-June 05 From: Bucuresti Member No.: 50.007 |
Mda... Mie imi este foarte clar ca tu ai o confuzie vis-a-vis de functionarea diferentialelor.
Din pacate timpul nu-mi permite sa dezvolt ideea, deh trebuie sa mai si muncesc... XDrive-ul este proactive Haldex de pe Audi este proactive Torsen - nu este proactive LSD VC - nu este proactive LSD ar putea fi proactive (depinde de constructie) EDL este proactive ..... Multumit? Am sa revin cand timpul imi permite P.S. 2 studii de caz in vederea intelegerii functionarii diferentialelor deschise: 1. O masina FWD (un Golf III sa spunem) cu diferential deschis pe fata, are roata din dreapta pe gheata iar cea din stanga pe asfalt. In cazul accelerarii puternice, care este distributia cuplului intre cele doua roti? 2. Aceleiasi masina i se aplica frana doar pe roata dreapta. Care este distributia cuplului in acest caz? -------------------- Audi A4 130CP - 2002
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Nov 21 2005, 05:37 PM
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#69
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Subaru Anti-Hero Group: Moderator Posts: 5.323 Joined: 13-May 04 From: F 1 World Member No.: 25.368 |
QUOTE(Valentin50014) Am sa revin cand timpul imi permite
Ajuta-ma tu sa intzeleg asa cum vrei tu. http://www.subaru-global.com/about/awd/poise/index.html Center Differential 
http://www.subaru-global.com/about/parts/06.html QUOTE Subaru's center differential contributes to performance for ideal traction for all four wheels by appropriately distributing the torque. Moreover, a racing driver noted, "Driving a car involves controlling the traction to all four wheels." Subaru's center differential regarded this as important function and actually achieved. The center differential is one of the main factors that enables AWD driving performance, which is responsive and superbly faithful to the driver's will.
The VTD of the Subaru Legacy is patented technology called "double-planetary gear type variable torque distribution." This VTD has a mechanism consisting of helical gears-- one front sun gear, one rear sun gear and three planetary gears, and one carrier. http://www.subaru-global.com/about/awd/per...ance/index.html Eu...is mai sarac si mai fraier -uite vezi recunosc - QUOTE Torque Distribution system.
Whether it's tackling a gravel-strewn FIA WRC special stage, or simply running into standing water on tarmac, keeping your car stable by getting the best possible traction is vital. That's where the technology of our torque distribution system sets Subaru apart from conventional 4-wheel drive set-ups. Evolved from the very outset specifically for Symmetrical AWD, it actively distributes engine torque to individual wheels - not just to front or rear axles, as some others do. In fractions of a second, our smart system automatically adjusts the amount of torque, giving maximum grip and stability wherever and whenever it's needed - not only in extreme conditions, but in everyday driving. The result is dynamic handling that feels truly intuitive, making the car behave like an extension of the driver's body and mind. So, even when road conditions change unexpectedly, torque distribution plays a crucial role in achieving the goal of stability and control. Maximum grip showcase LSD(Limited Slip Differential) LSD(Limited Slip Differential) At the very core of this complement to AWD stability is Subaru's centre limited slip differential. A sophisticated mechanism controls torque distribution and limits tyre slip pro-actively, rather than reactively, depending on the different surfaces you encounter along your journey. This real time adjustment makes sure that a Subaru always uses its AWD traction and stability to the full. But it's not just for slippery and adverse conditions either. So, while you may never see our central differential in the flesh, it's very reassuring to know that this marriage of technology and mechanical engineering is constantly working with all the other Subaru technologies, to keep your car more stable, and you safer. Este o mica animatzie care poatre te intereseaza http://www.subaru-global.com/about/awd/per...ance/index.html Maximum Grip Showcase - Corner & Wet Road M-am plictisit. Acum invatza-ma si tu ceva. Pe bune si cu toata seriozitatea. Eu sint confuz si pretind anumite chestii care nu sint adevarate...despre masina saracului. Daca eu am transmisie manuala...si intr-adevar nu am TOATE chestiile astea pe masina (asta imi este neclar) nu inseamna ca Subaru face sisteme AWD inferioare si de toata bafta cind le compari cu X-Drive sau QUATRO sau mai stiu eu ce. Din ce am citit...pe site-ul lor...si Subaru are pro-active, si cu timpi de reactzie in fractziuni de secunda. Exact aceleasi cuvinte folosite si in link-ul despre X-Drive de mai sus. intre timp ma duc sa cersesc niste bani de la locul de munca (este 8:30 AM )...ca doar eu sint sarac si nu am cum sa imi permit "opere de arta" ci doar masini similare statutului meu social. -------------------- Schumi drive it like you stole it !
2005 Subaru Legacy GT ; 2009 Subaru Forester XP ; 2014 Jeep Grand Cherokee |
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Nov 21 2005, 06:57 PM
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#70
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perioada de proba Group: Membri Posts: 5 Joined: 2-October 05 From: Constanta (Constanta) Member No.: 57.308 |
QUOTE(f1anatic) [Link-ul imi place...cu toate ca as putea face talente...ca vezi doamne...ghici unde era aceasta informatzie...pe un forum al GERMAN CAR FANS.
Numai aici am gasit pe larg explicatii Dar nu este PRO-ACTIVE Cum zici tu ...[/b] QUOTE BMW xDrive distributes drive power infinitely and fully variably between the front and rear axle. The system immediately recognises the need to change the distribution of engine power and responds extremely quickly, usually before a wheel even loses grip when driving onroad. As a result, xDrive feeds exactly the right drive power to each axle when, for example, taking a bend fast and dynamically, in the process significantly reducing both under- and oversteer.
The electronically controlled multiple-plate clutch in the power divider controls the flow of power to the front axle within milliseconds as a function of individual requirements. In extreme cases the front and rear axles are even fully disconnected from one another or rigidly, firmly connected to form one unit. [b] Oh wow...axele sint deconectate una de alta...adica no traction...adica soferul devine pasager...la mila computerului. Asta...sincer mi-a zbirlit parul pe spate...de ajunsesem un arici Imi pare rau dar ... nu pot spune ca nu cunosti limba si de aia traduci mot-a-mot dar daca citeai tot articolul ai fi inteles ca din cauza tipului de "clutch" axe deconectate inseamna 100% pe spate(fata) conectate full inseamna 50-50. Intervening electronically in the brakes, DSC provides the same function as a transverse wheel lock with forced distribution of power to the front and rear wheels: As soon as a wheel starts to spin without conveying power, the brakes cut in to slow the wheel down, the differential in the final drive thus feeding more power to the opposite wheel. Asta inteleg ca nu ai citit . EXEMPLU ! Ok si prima referintza la transfer lateral. Pai...tot la parerea initziala ca da...e avansat...citeste situatzia drumului mai repede si poate face ajustari mai repede...dar treaba asta cu pseudo - traction iar ma agita. Pai ma scuzi...asta nu este transfer lateral adevarat...Pur si simplu...daca creierul masinii a decis ca puntea fatza are nevoie de 30% ...iar puntea spate 70%...atunci daca roata dreapta spate dintr-o data pierde tractziunea...inseamna ca frina dreapta spate o frineaza...si deci contributzia ei de 35% (jumatate din 70% cuplu dedicat puntzii spate) este pierdut in neant...iar masina opereaza pe stinga fatza 15% dreapta fatza 15% stinga spate 35% dreapta spate 0% (frinata) Teoretic ai dreptate pt "a few miliseconds" pana cand cuplul este redistribuit intre punti . Pai I am sorry...dar la Subaru pot trimite pina la 100% la oricare 2 rotzi. Diferentzialul pe fatza la Legacy este deschis (la fel ca la Audi, BMW) deci orice primeste puntea fatza se imparte fratzeste pe din 2. Dar in situatzia precizata mai sus...asa...incet cum este...ca doar masina saracului nu poate reactziona in a few milliseconds...ci in citeva minute....tot cuplul este transferat la roata ailalta. Dupa care sistemul tinde din nou spre 50%-50% fatza spate. stinga fatza 15% dreapta fatza 15% stinga spate 70% dreapta spate 0% (nefrinata, dar fara cuplu) Imi pare rau dar m-ai pierdut pe drum aici. Deci masina are 50 - 50 de 25 25 25 25 Intra dsc sau ceum se numeste el si taie o roata. Deci ramai cu 25 25 25 0 In afara situatiei in care tu ai pus 70-30 si ai taiat din aia 70(de ce nu ai taiat din 30?) situatia este similara si aceeasi. Situatiile de genul asta nu dureaza nici 2 sec. Iar daca amestecam si STi-ul in povestea asta...cu diferential LSD si pe fatza...cu DCCD (driver controlled center differential - electronic by the way, sau automat de creierul masinii)...pot spune ca puterea poate fi trimisa 100% la o singura roata. Asa...cu tot visco-cuplajul asta antic de pe vremea lui Fuji-san si a fiului sau Subarumoto. Pe sosea uscata sau cu ceva ploaie ...as prefera BMW...pt ca fara LSD (centru, spate), pierderile prin transmisie sint mai mici. Dar cind e vorba de business adevarat cu zapada si ploaie serioasa...cred ca imi prefer masina de om de rind. Imi placi cand pozezi in victima! De fapt ceea ce vrei tu sa zici este ca preferi o transmisie cinstita de off-roader din anii 60-70 decat un sistem electronic ergonomic si automat. Daca spuneai asta de la inceputul topic-ului era mai simplu. Dar nu incerca sa ne demonstrezi ca electronica mecanica si masinile in general nu au mai si evoluat din anii 70. bafta |
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Nov 21 2005, 06:58 PM
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#71
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perioada de proba Group: Membri Posts: 5 Joined: 2-October 05 From: Constanta (Constanta) Member No.: 57.308 |
Imi cer scuze nu sunt obisnuit cu acest forum daca nu se intelege moderatorul poate sa stearga postul de mai sus.
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Nov 21 2005, 07:46 PM
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#72
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Subaru Anti-Hero Group: Moderator Posts: 5.323 Joined: 13-May 04 From: F 1 World Member No.: 25.368 |
QUOTE(Mihnea57315) Imi cer scuze nu sunt obisnuit cu acest forum daca nu se intelege moderatorul poate sa stearga postul de mai sus.
No problem. Dar spunemi si mie...de ce sa frineze roata ? Parerea mea este ca nu este un transfer real de cuplu la roata opusa. Pe de alta parte...incerci sa ma convingi ca acest sistem evoluat este mai bun decit ce ofera Subaru. Ceea ce ma face sa intzeleg ca nici tu nu citesti ce am scris eu. Ce are BMW nu este un LSD adevarat. Este un pseudo LSD...care are nevoie sa frineze roata fara tractziune - si repet - nu sint convins ca este transferata puterea la roata opusa. Nu imi este clar ce este acest "differential in the final drive"...de ce nu se zice clar ca "axle differential" trimite puterea la roata opusa ? Pentru ca...nu are ? Parerea mea...dupa tot ce am citit si de la unii si de la altzii este ca la BMW nu se transfera puterea lateral...ci numai este taiata puterea - prin frina - de la roata care nu are aderentza. Daca dadeai click la ce am pus mai sus...ai vedea ca sistemul invechit din anii 60-70 de pe Subaru...este atit pro-active cit si foarte rapid... si are transfer de cuplu adevarat de pe o punte pe alta respectiv de pe o parte pe alta. Fara a fi nevoie de frinat rotzi. Fara electronica in plus. E usor sa ma convingi ca anumite moduri de operare al sistemului AWD de pe Subaru este incompatibil cu alte sisteme. Si ca Haldex, Torsen au avantaje fatza de AWD-ul de la Subaru. Si invers. Dar e foarte greu sa ma convingi ca e mai avantajos si/sau mai evoluat sa frinezi o roata pentru a transfera cu adevarat cuplul (ceea ce repet nu cred ca face X-Drive) cind altzii o fac mai ... adevarat...printr-un sistem mai "mecanic" - deci mai putzin afectat de probleme de software, senzori suparazti unul pe altul. E buna si electronica...dar nu este o solutzie pt. orice. Ma rog...sa ne intilnim pe zapada. INTREBARE PT. ADMIN Am un filmuletz de 18 mb...pe care as dori sa il arat. Cum fac ? CONCLUZIE Daca nu am spus-o o repet. Toata viatza o sa tinjesc sa pipai un AUDI cu quattro si DSG...instalat intr-o "opera de arta" ca BMW Series 3. -------------------- Schumi drive it like you stole it !
2005 Subaru Legacy GT ; 2009 Subaru Forester XP ; 2014 Jeep Grand Cherokee |
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Nov 21 2005, 07:51 PM
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#73
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 workaholic * * * * * * Group: Moderator Posts: 11.052 Joined: 4-August 03 From: Bucuresti Member No.: 14.854 |
se uploadeaza pe www.rapidshare.de
si apoi se da linkul aici -------------------- |
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Nov 21 2005, 08:03 PM
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#74
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Subaru Anti-Hero Group: Moderator Posts: 5.323 Joined: 13-May 04 From: F 1 World Member No.: 25.368 |
QUOTE(Valentin50014) P.S. 2 studii de caz in vederea intelegerii functionarii diferentialelor deschise:
1. O masina FWD (un Golf III sa spunem) cu diferential deschis pe fata, are roata din dreapta pe gheata iar cea din stanga pe asfalt. In cazul accelerarii puternice, care este distributia cuplului intre cele doua roti? 2. Aceleiasi masina i se aplica frana doar pe roata dreapta. Care este distributia cuplului in acest caz? Pai daca tu pui intrebarea asta...si tzie itzi este neclara functzionarea diferentzia.lelor. Sorry to say it. QUOTE http://www.houseofthud.com/differentials.htm
So what's wrong with the open diff? The problem is an open diff always tries to balance the torque. That's a hard statement to get a grasp on, but it means that if the spider gears are pushing on both drive gears and one of them offers lots of resistance (tire sitting on pavement) and the other side offers no resistance (up in the air, or sitting on a patch of ice), then it will find a happy balance where both sides are receiving almost no torque at all. All the rotational energy is guided to the side with the least resistance. In the end, that side spins very fast and the pressure on each drive gear is the same.. Almost no torque is needed to spin one wheel, and therefore almost no torque is going to the other side as well. Anyone who's driven on snow or ice knows this trick. http://www.houseofthud.com/differentials.htm QUOTE EDL (often referred to as Electronic Traction Control.)
This system is used by the VW GTI-VR6 (FWD) and Mercedes ML320 (AWD) and probably others. It's the poor man's LSD. (Some people dislike my characterization of it, as it can be very finely tuned, but it's still very cheap to implement and has some reliability problems.) http://auto.howstuffworks.com/differential2.htm Open Diff http://auto.howstuffworks.com/differential3.htm -------------------- Schumi drive it like you stole it !
2005 Subaru Legacy GT ; 2009 Subaru Forester XP ; 2014 Jeep Grand Cherokee |
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Nov 21 2005, 08:10 PM
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#75
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Subaru Anti-Hero Group: Moderator Posts: 5.323 Joined: 13-May 04 From: F 1 World Member No.: 25.368 |
QUOTE Like the viscous coupling, they are often used to transfer power between the front and rear wheels. In this application, the Torsen is superior to the viscous coupling because it transfers torque to the stable wheels before the actual slipping occurs.
However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero. http://auto.howstuffworks.com/differential10.htm Deci...sa ma repet... -------------------- Schumi drive it like you stole it !
2005 Subaru Legacy GT ; 2009 Subaru Forester XP ; 2014 Jeep Grand Cherokee |
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Nov 21 2005, 08:12 PM
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#76
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workaholic * * * * * * Group: Moderator Posts: 11.052 Joined: 4-August 03 From: Bucuresti Member No.: 14.854 |
hai cu filmuletul
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Nov 21 2005, 09:00 PM
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#77
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Subaru Anti-Hero Group: Moderator Posts: 5.323 Joined: 13-May 04 From: F 1 World Member No.: 25.368 |
QUOTE(G e o r g e) hai cu filmuletul
George nu il ai tu ? FLAINE ? Un Subaru STI alb, filmul parea francez ? A aparut prin Februarie 2005 ? Un Sti alb mergind la munte si cobora FOARTE repede un drum acoperit cu zapada ? -------------------- Schumi drive it like you stole it !
2005 Subaru Legacy GT ; 2009 Subaru Forester XP ; 2014 Jeep Grand Cherokee |
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Nov 21 2005, 09:01 PM
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#78
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workaholic * * * * * * Group: Moderator Posts: 11.052 Joined: 4-August 03 From: Bucuresti Member No.: 14.854 |
ahhhhhhhhhhhhhhhhh ALA ? pai e deja pe rapidshare.de
 sa caut linkul 
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Nov 22 2005, 12:38 AM
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#79
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specialist Group: Membri Posts: 584 Joined: 28-June 05 From: Bucuresti Member No.: 50.007 |
QUOTE When it comes to secure handling and stability, in normal or adverse conditions, Subaru's Symmetrical AWD will always have the edge over other 4WD systems. Here, instinctive rally-proven capabilities inspire you to drive the car as you want - even when travelling fast over rough or slippery roads, where traction can easily be compromised. Again, it's all about the enjoyment of handling Subaru cars with complete confidence. In other manufacturers' systems, low traction levels usually activate some form of traction control, instead of relying solely on the vehicle's AWD ability. That's what can lead to instability when cornering on wet or greasy surfaces. At Subaru, we believe that the first line of defence should always be Symmetrical AWD, which constantly keeps grip at its best. However, we also recognise that sometimes, a driver could meet with a situation that needs quite sudden and violent avoiding action. Where reaction is delayed, the steering wheel may also be turned extremely quickly to swerve away. This could then possibly precipitate a spin
Uitea culmea ipocriziei (stai linistit, toate firmele procedeaza la fel). In primul mesaj critica neputinta altora de a realiza sisteme mecanice, acestia fiind nevoiti sa se foloseasca de electronica pentru a suplini lipsa de performanta a sistemelor lor AWD. Mai jos iata ce spun... QUOTE That's where Subaru Vehicle Dynamics Control* system saves the day. As an adjunct to the full-time security of AWD, it acts as a vital backstop in emergencies, kicking in only when it's really needed. Sensors monitor vehicle speed, throttle opening, gear position, lateral G, yaw rate, brake status, steering wheel angle - analysing the actual driving situation. Then, a computer simultaneously co-ordinates control of torque distribution, engine output and ABS - using braking on the outside-front or outside-front and rear tyres to stop the car from spinning. None of which detracts from your everyday pleasure in driving your Subaru. But even if Subaru Vehicle Dynamics Control system never betrays its presence, it's very reassuring to know it's there if needed.
* Available on certain models. Adica exact ceea ce faceau ceilalti, numai ca aici Subaru este din nou inaintea tuturor. Ceea ce "uita" ei sa spuna este ca fragmentul al doilea este valabil doar cu cutie automata (ma rog, este o steluta acolo). Daca in primul caz critica concurenta, in cel de-al doilea caz aduce elogii unui sistem care nu functioneaza decat cu cutie automata, asta in timp ce concurenta ofera acelasi lucru cu ambele transmisii. Adica noi suntem mai tari decat oricine ca oferim ESP pe transmisii automate, in timp ce ceilalti sunt slabi ca folosesc electronica. Pai ce, ESP-ul de pe Subaru e mecanic? Cum ramane cu AWD-ul concuretei compatibil cu cutiile manuale? Pana la urma intelegi cat de usor poti fi pacalit de marketing? Despre sistemele proactive: Asta este o alta inventie a marketingului. Practic nu exista nici un sistem care sa anticipeze cu adevarat momentul cand se pierde aderenta (la fel ca la ABS). Cele care sunt considerate proactive se bazeaza pe senzori de deceleratie, ei practic au o viteza de reactie mai mare decat celelate sisteme. LSD-ul cu VC nu are cum sa fie proactiv deoarece foloseste lichid siliconic care trebuie incalzit. Un sistem pur mecanic (cum este torsen) este indiscutabil mai rapid decat cel cu vascocuplaj, dar nici acesta nu este proactiv. -------------------- Audi A4 130CP - 2002
Panda MultiJet 1,3 |
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Nov 22 2005, 12:47 AM
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#80
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specialist Group: Membri Posts: 4.583 Joined: 30-May 04 From: Honda World Member No.: 26.577 |
cred ca toti producatorii in discutie folosesc termenul de "pro-active' in mod liberal (adica exagereaza in mod intentionat si in scop publicitar). daca Torsen este "pro-active" in comparatie cu vasco-cuplajul si EDL ( adica franarea electronica a rotilor care patineaza) este "reactive" in comparatie cu LSD ( care este din capul locului si mecanic "pro-active").
pe de alta parte un diferential deschis cu un sistem electronic de franare nu duce la pierderea 100% a cuplului pe roata franata. diferentialele deschise trebuie vazute ca un dispozitiv care directioneaza cuplul catre calea de minima rezistenta ( deci daca o roata patineaza rezultatul va fi ca acea roata primeste, in mod ineficient, mai mult cuplu in timp ce roata care are tractiune primeste mai putin). Cu EDL in momentul in care o roata este franata cealalta ( care are tractiune) este vazuta de catre dif deschis ca fiiind calea de minima rezistenta si cuplu va fi indreptat unde trebuie. deci EDL e o idee excelenta dar ca mod de a pune cuplul motor pe asfalt este mai prost decat un LSD. de ex. daca normal cele 2 roti de pe o punte primesc cuplul pe puntea respectiva 50-50, odata ce una patineaza si este franata cuplul este indreptat preferential catre roata cu tractiune, ceea ce se pierde fiind proportional cu franarea respectiva. apoi aceasta franare este tranzitorie si imparteala 50-50 revine imediat ce roata care a patinat recapata tractiunea. stiu ca C&D a facut un teste interesant in comparo-ul STI vs. Evo masurand acceleratia pe un traseu in care rotile de pe o parte erau pe nisip in timp ce celelate erau pe asfalt. STI a accelerat semnificativ mai repede fata de Evo care nu are LSD pe puntea fata. daca ai pune un A4 in aceasta situatie cred ca performanta ar fi mult mai slaba tinand cont ca ar merge cu rotile de pe o parte franate si o groaza de cuplu ar fi pur si simplu "ars" in franele de pe partea respectiva. in concluzie: Torsen al Quattro permite o distributie mai buna a cuplului fata-spate in timp ce STI ( si Legacy GT) permite o distributie mai buna a cuplului stanga dreapta. am observat de asemenea ca Legacy 3.0R are o acceleratie mult mai slaba (6.9sec) fata de Legacy GT (5.7sec 0-60mph / 5.9sec 0-100km/h). o parte poate fi atribuita cuplului mai mare, iar o alta parte prob. legata de ratiile cutiei de viteze care este in 6 trepte la 3.0R si in 5 la GT. George stii daca 3.0R are si el LSD pe spate? daca nu asta ar mai putea explica o parte din diferenta dintre cele 2. oricum un Legacy GT limited ( cu aprox aceeasi greutate si aceeasi putere) este semnificativ mai rapid ( 5.9sec) decat un A4 quattro 3.2l FSI (255CP) = 6.4 sec si decat un BMW 330xi= 6.4 sec care sunt muuult mai scumpe. e marginal mai putin manevrabil decat un 330xi dar par cu A4-le similar motorizat... -------------------- Civic Si 2007 2.0l DOHC iVTEC
Acura TL 2006 3.2l SOHC VTEC |
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