RE: Torsens: The Trojan Horse...

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

In my understanding VC stands for viscous coupled ... I do not believe that
there is ever a direct connection between the input and output of a VC ...
the coupling fluid tends to heat up as the differential speed increases and
the fluid is designed such that it gets more viscous as the temperature
increases.  It sounds like you are talking about a magnetically coupled
locking coupling in your post though, not a VC.  If a magnetically coupled
device were to be used, it would have to be controlled in some way based on
input from wheel speed sensors.  I am by no means an expert on all of the
various means that have been called to the task for creating an AWD vehicle,
but I've never heard of it being used in anything other than automatic
tranny torque converters.  

As much as open diffs and torsens have been called a simple minded means to
keep us going in the snow, my impression of the VC AWD systems is that it is
the same animal if not more so.  

So, I guess the outcome of all this brouhaha is that the best solution for a
performance app is the computer controlled clutch arrangement (a la 959 &
v8q automatic), followed a close second by the current ABS-based "EDL"
method (with the appropriate 3-axis acceleration sensors and wheel speed
sensors).  

This brings me back to a question I asked a couple weeks back ... ABS
algorithms.  Does anyone have any info on them (FWD, AWD)?  Does the ABS
system that supports EDL have any more sophisticated electromechanical
devices than does the old ABS system in the '86-'88 5000s?  

Steve Buchholz
San Jose, CA (USA)

... still incredulous that I ever decided to jump into this thread ... :)