[torsen] Re: Haldex differential

Keith Maddock Keith.Maddock at trw.com
Tue Nov 19 08:31:05 EST 2002


Scott,

I see where you are going with "torque shift" in terms of moving torque, as opposed to "torque capacity".  Though by your own rules, since the rear axle has 0% torque in the no-slip, and is then capable of receiving 100% torque at full lock (assuming strong enough clutch), wouldn't you call that a "shift" of 100% torque?

I understand if this was a locking or torsen diff, that since the no-slip torque transfer characteristic is 50/50, you're only "shifting" up to 50% more to either end, but the LSC isn't a differential based system like the torsen.

To-mayto, To-mahto? :)

I'll see what I can find out from the Haldex boys this winter :)   We'll be working with a Golf R32 and a few Saabs with Haldex Gen I's, and a S3 with a Haldex Gen II transplant, so I'm sure we'll have more than a few conversations with them!

Cheers,
Keith

****************************************************************
Keith Maddock, TRW Automotive,  Koblenz, Germany
Slip Control Systems, Systems Design, Traction Control
+49 (0)261/ 895 2474     -    -    keith.maddock at trw.com

>>> <QSHIPQ at aol.com> 14:00:12 19.11.2002 >>>
Keith and Dave:
You are both correct that a "locked up" haldex is *capable* of supporting 
100% of driveline torque.  As is a locked center.  Another terminology issue 
I suspect. 100% torque shift is theoretically possible for exactly the length 
of the wheelbase.  Not a commonly thought of in the context of any 
differentials (redefining a torsen to include 0torque?).  Torque allocation 
is commonly thought of more in the context of the ability to SHIFT, not the 
ability to support.  In the case of the haldex vc it can shift up to 45% of 
the available engine torque to the rear axle.  Another one for the SAE boys 
to figure out I suppose.

Keith.  IMU exactly that the current *device* is capable of being a full time 
awd system.  Not enough knowlege I'm afraid, to ask specifically *how* that 
is done, or whether that included full lockup all the time, tho I suspect, 
the pump and/or the throttle/relief valve (more likely) is capable of it. 

[snip snip to save space]

HTH

Scott Justusson





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