DPF active regeneration frequency
- Thread starter mattbryson
- Start date
When you go in to Carista and get the page that says force regen, keep looking at that page, after a short time the text will change and state the soot level
Ok - I ran the VAG DPF app with Carista and I have possibly got to the bottom of the frequent Re-gens.
Basically, (in my Van at least), passive re-gen is a myth!
You can't get the DPF hot enough to actually burn off the soot by driving the van.
I did a 55 mile motorway trip
Cruising at 70mph, 7th gear just shy of 2000rpm and the DPF was a steady 303 deg c - no where near hot enough.
I also ran at 60 for a while and no real difference.
All this time the filter was just slowly building up.
I did manage to get it to drop by one percent momentarily by flooring it, the temp shot up to almost 500 deg c, but then plummets back down when you back off.
After about 30 mins on the motorway, the Active re-gen kicked in when the filter was at 24g soot mass.
The Acitve re-gen got the temp up to well over 600 deg and slowly burnt the filter clear.
After 20 mins it turned off and the soot mass was back down to 5.5 grams.
So - no matter how much motorway driving I do - it doesn't actually clear the DPF - unless an Active regen kicks in.
This explains why the day after a long motorway trip the Active Regen will start.
I've no idea if this is normal - I was under the impression that driving it on A roads / Motorways caused a passive re-gen ?
Going to get in touch with VW and see - I have a suspicious wire that has been tapped off under the exhaust as well that needs looking at - might be related?
Thanks for the help and advice everyone.
Basically, (in my Van at least), passive re-gen is a myth!
You can't get the DPF hot enough to actually burn off the soot by driving the van.
I did a 55 mile motorway trip
Cruising at 70mph, 7th gear just shy of 2000rpm and the DPF was a steady 303 deg c - no where near hot enough.
I also ran at 60 for a while and no real difference.
All this time the filter was just slowly building up.
I did manage to get it to drop by one percent momentarily by flooring it, the temp shot up to almost 500 deg c, but then plummets back down when you back off.
After about 30 mins on the motorway, the Active re-gen kicked in when the filter was at 24g soot mass.
The Acitve re-gen got the temp up to well over 600 deg and slowly burnt the filter clear.
After 20 mins it turned off and the soot mass was back down to 5.5 grams.
So - no matter how much motorway driving I do - it doesn't actually clear the DPF - unless an Active regen kicks in.
This explains why the day after a long motorway trip the Active Regen will start.
I've no idea if this is normal - I was under the impression that driving it on A roads / Motorways caused a passive re-gen ?
Going to get in touch with VW and see - I have a suspicious wire that has been tapped off under the exhaust as well that needs looking at - might be related?
Thanks for the help and advice everyone.
Makes sense as it’s the engine load that affects the exhaust temp’. Cruising on a motorway is probably the most fuel efficient journey possible.
More time now and on PC
Under normal driving conditions your DPF will catch soot and the number will rise. I am not 100% on the passive, active and forced terms and their specifics either, but I'm sure someone will clarify.
My understanding:-
Passive regen is where you don't get much feedback so it should happen in the background, but the van is 'actively' doing something to make it happen. It is chucking more fuel in to get the DPF up to the 600C to burn the soot. Revs are high (1000 rpm at tick over) and fans stay on when you turn it off, and it stinks. No dash lights, unless you trigger this through Carista, or other. Happens at 30g on my van and down to 8g, so similar to yours.
When light comes on it means you should 'actively' take it for a drive at 2000+ rpm to enable it to complete regen. This happens when your van has not been able to complete the passive regens and soot levels are getting high. I think ~35-40g. However, I think the light goes out when the soot is below 30g (or 24g) in your case, so people think its done, but it isn't.
Forced regen is when the dealers get involved with software triggers cos the vans gone into limp mode due to too much soot build up. ~50g I think. Don't let it get to this stage.
There is plenty of info on here. Search for @mmi posts. There is detail about the different trigger levels, but it may also be software version related. I have the latest software on mine now, and it does seem to handle the whole regen thing better, like it doesn't seem to care about the fule tank being 1/4+ or about the van being hot, it just gets it done.
It's recommended that you keep the revs above 2500 for a regen.
My van is a DSG so I shift the gear lever to manual and keep it in either 5th or 6th depending on speed.
Great, that's what I was hoping!
Ah, I thought passive was that the van had no part of it, it was just the natural heat from the exhaust.
Anyway, it sounds like it's working as designed. It's just a crap system
Miles or KM?
My driving distance between regenerations dropped down to
53 miles ≈ 85 km (no faults in the ECU).
At that rate I have decided to remove my DPF and get it professionally cleaned(£75 ≈ €90).
After reinstallation everything seems to be okay and regeneration frequency definitely dropped.
I didn't get a chance to verify my new interval between regens yet but it looks promising.
Also I have reset to 0 my OIL ASH MASS as it was very close to 110.00g limit. Not sure if this was really compulsory but I did it a s common sense approach.
