Haldex

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Haldex is a Swedish company manufacturing for example the Haldex electro-hydraulic limited-slip "coupler" (LSC) or clutch, used in vehicles with automatic "on-demand" four-wheel drive systems, to engage and disengage a secondary axle when needed.

"Haldex" refers to the aforementioned coupling system — its most prominent use is in all transverse engine 4x4 models of the Volkswagen Group (Volkswagen AG): (Audi A3, S3 and TT, and Volkswagen Golf), making them non-permanent 4x4s, unlike longitudinal engine models (Audi A4, A6, A8, previous-Volkswagen Passat), which use a Torsen centre differential. However, its short reaction time (only a seventh of a wheel spin) relative to systems like a viscous coupling, and ability to fully lock mitigate its theoretical disadvantage to a full-time 4WD (like Torsen) setup.

The Haldex LSC has been used in 4WD models of Volkswagen by the name "4motion", and Audi cars under the name of "quattro". The same labels have also been applied to Torsen-based, full-time 4WD systems from both VW and Audi, which has led to confusion and some amount of heated debate as to the relative merits of each system. This is nothing more than confusion over nomenclature; due to the fact that the original Audi Quattro coupé did use a torque-sensing centre differential (not Torsen, however), many fans believe that "quattro" refers to said type of 4WD system, not realising that it is simply a trademark. (It is interesting to note that "quattro" is also used on the Audi Q7 SUV, which uses neither Torsen nor Haldex; instead, it uses a BorgWarner system).

[edit] Haldex Traction

Haldex Traction is a part of the Haldex Group that is responsible for manufacturing and marketing the Haldex AWD system.

The Haldex AWD system is currently used in the following vehicle models:

The fourth generation Haldex system is called XWD (pronounced Cross-Wheel Drive) and will debut on the 2008.5 Saab 9-3.

The XWD system is based on completely new technology and includes such features as

  • Active rear electronic limited slip differential.
  • Pre-emptive engagement of rear wheels under hard acceleration.

[edit] External links

Sidenote:The Haldex system is not and has not been used in any Mazda vehicles.

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