DPF regeneration - why OEMs (VW) does it every 200-300 miles

This topic has come up before - "why does my DPF regen every xxx miles instead of only when its full?" I found this article light on details but hits a few high points and has a simple statement covering why DPFs regen so often. Manufacturers are trying to balance between less fuel consumption (regen too often) and not burning the DPF down (regen not often enough).

Interesting is the new sensor technology that should be able to tell the ECM, more accurately, how full the DPF is so regens are done less often.

Jason

PS: www.greencarcongress.com

Interesting but they are selling something, so there is that. Delta Pressure
or pressure drop is pretty accurate. However I think VW is a little more
clever. It looks at a few other parameters to trip the forced Regen. For
example the total ash load is an estimate based on mileage. There's no
direct measurement of the total ash build, it is indirect.

Typically I have few Regens; my guess every other tank, about 1200 miles.
I say guess, because I may not always notice. I have EGT/Boost/Water Temp,
so if I look at the ScangaugeII, see high EGT (1200F), I know a Regen is
happening. I think people who have Freq Regens are driving in a way that
builds up soot, a lot of slow stop and go, verses fast high speed (high EGT)
temps that promotes passive Regens. It is possible their Delta Pressure
sensing is out of calibration.

From un-official sources VW programmed their cars to perform a forced regen at least every 300 miles (exact number is somewhere high 200's). Doesn't matter if the whole time is >70mph highway the regen is still being forced. I haven't seen any official statements because engineers don't feel we really need to know that. Club members posting on here have backed that claim up. Too bad there isn't (or nobody found it yet) a MVB that clearly shows "regen active".

Jason

I have a Polar FIS installed, and watch DPF status.

this seems the same as engine controller MB 104-1 (which is labeled 0XFF02=done) visible with VCDS.

while this (with the next, 104-2) seems to be a data exchange word coded with values only known to the programmers,

my read is that, for my 2009 car, the values indicate the following:

FF01 Normal
FF10 DeNOX regen
FF02 DPF active Regen
FF20 DeSOX regen (lasts much longer... right after an FF02, every third to fifth time)

Well, damn! I'm putting that in my notebook! I guess next CR Jetta (or my Beetle) I get I'll check those out.

Jason

Some of the cars do not have the same measuring blocks, so you may or may not be able to get the indication.