q2

[veXon]

Sramota me da pitam.... Oce neko da mi objasni sta znaci oznaka q2? Koliko sam ukapirao ima veze sa upravljanjem i sistemom bezbednosti, zanima me na sta se konkretno misli? I da li se jos nesto sem upravljanja i podrazumeva pod ovim sistemom.... q2 me je zbunjivao jos na 147 a sad vidim da se javlja i kod GT-a...

[Milos]

Alfa Romeo presents the self-locking front differential (?Q2?), which improves all the strong points of a front-wheel drive system in terms of active safety, increasing driving enjoyment and control. The innovative system provides some of the advantages typical of four-wheel drive, but at a significantly lower cost and weight.

The system is now available exclusively with the 150 bhp JTDm engine on the Alfa GT and Alfa 147, but will subsequently be extended to other models in the Alfa Romeo range. It is a step forward that reflects the current state of the art of turbodiesel technology which, since 1997, the year that the Alfa 156 JTD was launched (the first car to adopt Common Rail technology), has seen a considerable increase in torque delivery to the wheels even on compact cars. Alfa Romeo has developed the sophisticated ?Q2? system to guarantee maximum control and traction in all driving conditions.

How the Alfa ?Q2? system works

The main element of the ?Q2? system is a limited slip differential, of the Torsen mechanical type. This differential splits torque between the front drive wheels dynamically and constantly, according to driving conditions and the road surface. Combined with the exclusive double wishbone front suspension, the system allows very effective fine tuning of the car.

Alfa Romeo started from the excellent reputation that front-wheel drive enjoys with customers (in fact it is the layout chosen by the majority of car-makers). Suffice it to say that, in addition to the overall benefits of this type of architecture (weight, roominess, etc.), in extreme conditions, the understeer typical of front-wheel drive enables the driver to respond more intuitively to the car?s reactions: this gives the impression that front-wheel drive is more ?responsive? than rear-wheel drive.

To highlight these benefits, Alfa Romeo has developed the ?Q2? system which embodies all the strengths of front-wheel drive, significantly increasing roadholding, traction and stability on the release, while attenuating understeer on acceleration, the intervention of the electronic control systems and steering wheel vibration.

The two practical examples below highlight the technical potential of the ?Q2? system.
Case no. 1: when the car corners

Taking a corner when grip is poor (wet road, snow, mud, etc.) or with a sporty driving style, grip is often lost on the inside wheel. When the transfer of the lateral load takes weight off the suspension, torque on the inside wheel is reduced, and a conventional differential (which splits the same torque value between both wheels) transfers an equal amount of torque to the outside wheel, but this is insufficient for good traction.

In this situation the car can respond in two different ways, depending on the equipment mounted. On a model without ASR-VDC, the perceived result is the slipping of the inside wheel, a loss of control of the car (strong understeer) and a loss of acceleration coming out of the bend. If, on the other hand, the car is equipped with ASR-VDC, the intervention of the driving assistance systems takes power from the engine, acting on the throttle valve and the braking system, so that it becomes impossible to modulate the accelerator, producing the unpleasant sensation of a drop in power.

In both cases, the result is that as the car comes out of the bend, the driver has the feeling that it is ?stationary?.

* What happens when the ?Q2? system is present

When the inside wheel starts to lose grip, torque is partially transferred to the outside wheel, producing less understeer, greater stability, and increasing cornering speed.

The improved mechanical efficiency of the ?Q2? transmission delays the intervention of the vehicle control systems, guaranteeing better traction as the car exits the bend, which makes driving more enjoyable and maintains complete control of the vehicle.
Case no. 2: surfaces with poor grip

On surfaces with poor grip, it is quite common for the drive wheels to have different degrees of grip. For example, grip under the two wheels can differ on snow-covered or wet roads.

In these conditions, starting off or accelerating sharply could cause the wheels to slip, generating critical friction conditions, a strong reaction on the steering wheel, and inadequate take-off, making it necessary to correct the steering-wheel continuously to maintain the trajectory.

* What happens when the ?Q2? system is present

The negative effects are attenuated by the gradual transfer of torque to the wheel that can exploit the best friction coefficient, simplifying a hill start, for example, and making driving on all roads with changing surface conditions safer and more comfortable.

[Nigy]

LSD, nesto sto 75 ima od '85...

LSD (limited slip differential), kod nas poznatiji kao sper ili delimicna blokada diferencijala, je ogromna pomoc u voznji (narocito na zadnjoj osovini). Lepo je videti da tehnologija ide ka tome da se i na prednju osovinu ugradjuje sper bez da to drasticno oteza nos vozila.

[starac vujadin]

Poenta je da je to Torsen diferencijal...sto je prvi put stavljeno na Integrale na 4wd automobilu, odnosno na Maserati Shamal na rwd.

[Milos]

http://video.google.com/videoplay?docid ... 1&hl=en-AU

[starac vujadin]

Dobar klip!

[chale]

Dobar texst, jos bolji klip, samo kad bi znao engleski
Neka mi neko kaze ko zna egleski ukratko ovaj Q2 sistem za sta ustvari sluzi, jeli to nesto ko ASR ili ESP ili nesto skroz drugo.

Dok su pametni ucili strane jezike, ja sam klosario!

[overspeed]

Ukratko, ono shto Q2 radi je sledece:

Kad unutrashnji tochak izgubi trakciju sa podlogom usled prebrzog ulaska u krivinu (zbog transfera mase), ili zbog losheg kontakta sa podlogom (sneg, kisha i sl.), obrtni moment se delimichno prenosi na spoljashnji tochak, chime se smanjuje understeer (proklizavanje auta "preko nosa"), povecava stabilnost i omoguciva veca brzina prolaska kroz krivinu.

Ovaj sistem, u najkracem recheno, dinamichki i konstantno rasporedjuje obrtni moment po prednjim (pogonskim) tochkovima, zavisno od trenutnih uslova i stanja podloge. Sistem dakle efikasnije prenosi snagu motora na put, trakcija pogonskih tochkova je bolja, automobil je stabilniji pri prolasku kroz krivinu jer je snizhen nivo prisutnosti proklizavanja "preko nosa", a ujedno je smanjen i efekat "torque steer-a", odnosno izbegnuta su neprijatna "shetanja" pogonskih tochkova u stranu pri naglim dodavanjima gasa. Sem toga, sistem takodje garantuje i bolju stabilnost u nekim drugim okolnostima, na primer pri naglom nailasku pogonskih tochkova na dve podloge sa razlichitim trakcijama (npr. levi na mokrom delu puta, desni na josh uvek zaledjeni deo), jer se obrtni moment tada automatski rasporedjuje na tochak sa boljom trakcijom itd itd.

Znachi, vrlo intuitivan (i interesantan) sistem, koji u saradnji sa nekim ostalim elektronskim sistemima koji se vec standardno ugradjuju na modernim automobilima, umnogome umanjuje ili anulira loshe efekte koji su u manjoj ili vecoj meri, ali uvek prisutni kod FWD automobila, vec zavisno od snage njihovih motora.

[chale]

@overspeed
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