DPF active regeneration frequency

[mattbryson]

Hi all,

First time owning a T6 and the joy of DPF that comes with it. It's an 18 plate 204, but has a revo stage 1 map if that makes a difference?

Just wanted to check if this sounds right...

I do one motorway trip a week ( 30 mins each way), and then some start stop town driving under 20mph.

The active DPF appears to kick in very frequently even with this motorway trip - sometimes after about 5-10 miles of
driving after.

So, I'm getting an active DPF regen at least once a week, with a 60mile round trip on the motorway and about 15-20 miles of town driving. does this sound right?

Cheers

Matt

 

[Dellmassive]

some extra infor here: DPF Regen, Yellow Light & Adblue - Whats It All About? -

 

[huw169]

Soot builds up quicker in a cold engine or doing more low speed journeys.
Regens will occur every approx 150 miles at worst to about 300-400 miles at best depending on your driving conditions.

 

[DXX]

If the map is for more power it’s going to be consuming more fuel which creates more carbon…..more re-gens.
Combustion efficiency will to some degree depend on how it‘s driven, foot to the floor will inevitably be less efficient than sensible acceleration.
Seems logical to me.

 

[mattbryson]

Yeah, so the map is probably making it worse, but I'm getting regens every 20 miles or so for town driving, which does not sound right based on @huw169 response.

No warning lights or codes reported by carista. It did a active regen this morning, I drove until it completed, so I'll see how many miles until it does it again.

 

[t6_tom]

I have the same engine and same map as you. My fuel economy improved and I was getting less regens after the map was done. Although it doesn't make sense initially the extra torque means I found you need to rev the engine less.

I tend to drive over 30 minutes each trip, not always on the motorway but rarely in stop start town traffic.

I always run my tank right down to the red and I get two regens per tank. Once directly after filling up and the second after about 250 miles.

 

[DXX]

I have the same engine and same map as you. My fuel economy improved and I was getting less regens after the map was done. Although it doesn't make sense initially the extra torque means I found you need to rev the engine less.

I tend to drive over 30 minutes each trip, not always on the motorway but rarely in stop start town traffic.

I always run my tank right down to the red and I get two regens per tank. Once directly after filling up and the second after about 250 miles.

The engine maybe producing the torque at lower rev’s but the extra fuel is still being consumed to achieve it.

 

[t6_tom]

That does make sense. However for my driving style I think the extra torque at low revs outweighs the extra fuel I was using a higher revs if that makes sense?

It wasn't a massive difference but I reckon I gained about 1 MPG.

On a side but relevant note I got the TVS gearbox map done a couple of months earlier and didn't notice and increase despite running more revs than on the original gearbox map.

 

[jimc91]

I have the same engine and same map as you. My fuel economy improved and I was getting less regens after the map was done. Although it doesn't make sense initially the extra torque means I found you need to rev the engine less.

I tend to drive over 30 minutes each trip, not always on the motorway but rarely in stop start town traffic.

I always run my tank right down to the red and I get two regens per tank. Once directly after filling up and the second after about 250 miles.

unless its change via a software update I didnt think a regen occurred once the tank was under a quarter, a vw service manager i spoke with blamed a lot of the regen problems he saw on clients running their van less than a quarter full so the regens were not happening as often as they should

 

[mattbryson]

unless its change via a software update I didnt think a regen occurred once the tank was under a quarter, a vw service manager i spoke with blamed a lot of the regen problems he saw on clients running their van less than a quarter full so the regens were not happening as often as they should

Yeah, that makes sense, I've not had it when the tank is under quarter full, and then after filling up it kicks in.

 

[mattbryson]

I have the same engine and same map as you. My fuel economy improved and I was getting less regens after the map was done. Although it doesn't make sense initially the extra torque means I found you need to rev the engine less.

I tend to drive over 30 minutes each trip, not always on the motorway but rarely in stop start town traffic.

I always run my tank right down to the red and I get two regens per tank. Once directly after filling up and the second after about 250 miles.

Great, good to know for comparison, thanks. I'll see how many I get since this mornings regen.

According to the blurb, that map has like for like fuel economy in "normal" driving conditions, whatever "normal" means

 

[mattbryson]

So, 45 miles / 2 days later and another active regen.

This was town driving, 2 trips about 15 miles, but did get to about 40mph for 5 mins. The rest was very short under 30 stuff.

To me this sounds like I have an issue...

 

[huw169]

So, 45 miles / 2 days later and another active regen.

This was town driving, 2 trips about 15 miles, but did get to about 40mph for 5 mins. The rest was very short under 30 stuff.

To me this sounds like I have an issue...

Until you get a Carista and monitor your soot levels you will always be guessing.

 

[mattbryson]

Until you get a Carista and monitor your soot levels you will always be guessing.

I have carista, I didn't know it could do that will check it out....

 

[Pauly]

Sounds like the regen may never be completing in which case it will just keep trying to redo it when the engine warms up ?

 

[huw169]

I have carista, I didn't know it could do that will check it out....

Go into service, and you’ll see DPF. It will give you current soot level.

 

[mmi]

carista.

So, 45 miles / 2 days later and another active regen.

You could monitor DPF regens by using free app VAG DPF Lite (however Android only) with your Carista dongle.
For your engine select "Custom engine group 15"

More experiments with the VAG DPF app here:

DPF Regen, Yellow Light & Adblue - Whats It All About? -

DPF Regen, Yellow light & AdBlue - Whats it all about? - The DFP light is becoming a more apparent issue with modern diesel vans, unfortunately, it’s a fact of modern diesel life. what is a DPF? Diesel particulate filters (DPF) are very effective in cutting emissions, trapping even the...

www.t6forum.com

 

[mattbryson]

Can't see anything other than force a regen in carista, but VGA DPF worked....




I'll get the paid one and monitor it, I've have no idea what the levels for the soot mass should be, I'm assuming 6.5g is OK at the mo as it's just done a regen?

 

[Lloydy]

I've got 2017 150 manual, nearly 88k miles and mine regens at 24g soot level approx every 150miles, its going in for cambelt change soon and I've asked them to check if I got latest software installed as most people on here reckon they regen on 30g soot level. Still getting 550 plus to a full tank.

 

[mmi]

Can't see anything other than force a regen in carista, but VGA DPF worked....

View attachment 136445


I'll get the paid one and monitor it, I've have no idea what the levels for the soot mass should be, I'm assuming 6.5g is OK at the mo as it's just done a regen?

For your engine you'll see that DPF regen heat-up starts at 24.0 grams and then very soon the soot level starts to fall down. Active regen stops at 6.00 grams but driving then light-footed the afterheat still keeps burning soot off up to 3 more minutes. Might get even below 5 grams if you don't cool down the DPF by revving the engine (=cold exhaust stream).

The paid VAG DPF can record the data so could plot fancy graphs afterwards.
E,g. here:

[T6_measured] DPF regeneration vs. short journeys

Got curious how T6 copes with doing short journeys. And how short would be too short for successful DPF (Diesel Particulate Filter) regeneration. The graphs below are result of doing short journeys - the plotted one is number 3, thus two interrupted DPF regens before this. At this stage the...

www.t6forum.com

Those were made by VCDS thus there besides soot levels are a few more parameters in there (e.g. speed, engine revs, actual fuel flow, etc).

So, 45 miles / 2 days later and another active regen.

My guess what happened:
The engine software (04L906056KQ/3775) has an interesting feature re DPF regens. If engine is turned off when regen has reached more than 70% the full regen cycle (soot from 24 grams down to 6 grams), the regen does not continue any more when engine is restarted next time. Instead engine runs normally till soot level has again reached 24 grams. Thus this next regen seems to come fairly soon after the last (actually only partial) regen.
The above applies the stock software - thus assuming the remap didn't mess with DPF regeneration process.