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RE: VC vs awd

Dave writes:
>please explain to the list scott how an awd system with a centre diff
>followed by a vc can be "full time awd"?
>perhaps you could start by describing how a vc can distribute torque in the
>absence of slip?
>you should remember that a epcyclic diff with a fixed torque split will have
>no effect until the vc starts to lock.in breathless anticipation.

Dave, this concept has eluded you for some time.  VC with Center Diffs are 
rather easy to be full time awd.  Toyotas system for example, uses an open 
diff center differential that transmits power equally to both front and rear 
driveshafts (effectively an open center diff awd).  When slip occurs, the VC 
coupling effectively locks the center and rear drivshafts (think of it being 
"around" the center diff).  Toyota has some simple illustrations available 
for you.  The Mitsu system operates one step further in the 3kgt/stlth tt, 
with a split center diff (not open, but split to rear bias), then under slip 
the VC locks the two driveshafts (again "around" the center diff) locking the 
diffs 50f/50r.  Both these systems are awd in the true sense of the word, as 
all wheels are driven all the time.  For more on this, you might want to look 
at some white papers at how front and rear VC differentials work.  Your 
thinking to date would mean that a rear or front diff is only 1 drive wheel 
until slip occurs, never been the case in every f or r VC diff., they are 
open diffs until slip occurs

I'm surprised with all your white paper, this awd concept eludes you.

HTH clear up the confusion you raised.