Thanks all, folks for the answers

@CCTaylor - I don't get the idle behaviour, why it does not regen at idle? Or let me put it this way, why it still holds higher rpms and deactivates the Start/stop?I thought the active regen pumps fuel to heat the filter and could do it even on idle.

I don't insist being right, just thinking loud...

According to you, as far as I got it, it will keep undefined period idle, and actually work once the car starts moving, right?

@Sheldon.Cooper - exactly! you drive and it does passive regens all the time as the engine is loaded (you don't see those) but stopping in city traffic active one starts, as the heat is not blown away from the air flow when driving.

This heats the DPF and some trigger starts the active regen. This was very annoying before I read for the passive ones, still it's annoying

 

Regen can occur at idle but it is much more inefficient than when driving under load where the exhaust températures & airflow are naturally higher.

So unless a regeneration is critical, it is likely that late injection is not active & it is just trying to maintain temperature in the exahust (by disabling EGR, increasing alternator load & increasing the airflow to maintain the current process) as it expects you to continue driving at some point. (rather than sit in Tesco car park at idle for half-an-hour)

 

The DPF does not continuously regenerate as your drive around.

Regeneration is not efficient when the DPF has low soot because soot is required as part of the process

Regeneration will only start once the estimated soot load of the DPF reaches a certain threshold e.g. 60% full.

So you could drive for 500miles without needed a regeneration.

 

I would expect after exceeding this threshold, the ECU looks for an opportunity to perform a passive regeneration (where the engine températures are already almost hot enough so minimal extra fuel is required).

This is why regeneration often happens when leaving the highway to drive on A or B-roads.

 

If regeneration is not possible & the DPF load increase to e.g. 70% then the ECU looks for the opportunity to perform active régénération where extra fuel is injected into the exhaust to increase the DPF temperatures.

Edited 5 September, 20169 yr by Gabbo

Tesco regen not good then.

 

Perhaps I'll try Waitrose next time - better class of particulate there and free coffee as well. :coffee:

On 9/1/2016 at 14:22, Gabbo said:

You only have to worry about the DPF if the light comes on.

 

I'm still trying to figure out this regen business, but my question is more mundane -- where is this DPF light?

My owner's manual [p32] mentions no such warning light. And if I had a problem how would it show?

Edited 21 May, 20188 yr by kenppy

This might be of some help to you

 

https://www.hypermiler.co.uk/dpf-diesel-particulate-filter/skoda-octavia-iii-2013-diesel-particulate-filter-dpf-owners-manual-regeneration-faq

 

Shame you cant use VCDS to code the light to come on when a regen is active and off when it's finished.

Skoda would have been 'simply clever' to have enabled an option on the car to highlight regen in progress.

ive had a couple of regens and you will know, huge amount of smoke and i even experienced a loss of power, always occurs on the motorway or dual carriageway.

 

11 hours ago, kenppy said:

On 9/1/2016 at 14:22, Gabbo said:

You only have to worry about the DPF if the light comes on.

 

Thanks for the replies -- I'm still puzzled, is there an actual warning light on the dash that comes on as my original quote suggests?

11 minutes ago, kenppy said:

Thanks for the replies -- I'm still puzzled, is there an actual warning light on the dash that comes on as my original quote suggests?

 

Yep, not in main instrument binnacle though:

 

 

Courtesy of @silver1011 from this thread:

 

 

 

I think you get both.

 

The regular orange warning on the dash, plus the warning in the 'vehicle status' section accessed through the radio.

 

This light only illuminates if there is a fault though, I forgot to check if it comes on briefly after turning on the ignition.

 

15 hours ago, JohnnyType2 said:

ive had a couple of regens and you will know, huge amount of smoke and i even experienced a loss of power, always occurs on the motorway or dual carriageway.

 

This is not normal.

When regen is occurring you should not really know it is happening & if you get smoke coming from your exhaust then your DPF is broken or you have a leak in the exhaust line.

The whole point of a DPF is to catch the soot, smoke & particulates...

On 01/09/2016 at 10:43, TTodorov said:

Hi!

After reading the VW service document PDFs I feel more relaxed but still few DPF questions tortures me.

1. How many km(miles) is set to force active regeneration, no matter the soot level?I've read here its like fixed interval to force, beside the other needed regens.

2. The car has 5000km and regens frequent no matter the driving style, does it make any difference by the time passed?

3. How long regularly active regen lasts?I've read in the documentation around 10 mins. Today I left it 30-35 mins on idle, the start stop did not activate, the rpms were still high. Had to go and stopped it.

4. Does the start stop enabled helps the DPF cycles or worsen the situation. Compared to idle.

P.s. I want to know more, no issues here.

 

My experiences ...... It's very easy to get a bit hung up on the DPF and regens, I Used to!  I ended up buying one of those Bluetooth ELM OBD scanners and linked to my phone through the VAG DPF app and monitored it for A few weeks.

 

As a rough guide, mine forces a regen when it reaches about 24 grams of soot, at this point the DPF heats up to about 600+ and the regen starts.  The regen will continue unless interrupted and finishes leaving about 5 grams of soot from memory.

 

if you turned off mid regen and say had burnt off 4 grams of soot (so 20 grams were left) it wouldn't start a regen the next time you drive, it would wait till it got back up to 24 grams again (from my experience)

 

If the DPF naturally gets up to about 330 deg C, the car will start to regen no matter how much soot there is - I found doing 80 mph in 6th wouldn't quiet achieve this ( it started regen then stopped, started then stopped) so you'd need to be in a lower gear at higher revs to get it to regen.

 

My driving style doesn't seem to effect things the soot weight seems to go up pretty much equally no matter the driving style.

 

Start stop won't really achieve anything other than the engine won't generate soot when the engines off.

 

I haven't used the adapter since, if it's doing a regen when I pull up at my destination then it is what it is ..... I turn the engine off.

2 hours ago, ScoutCJB said:

If the DPF naturally gets up to about 330 deg C, the car will start to regen no matter how much soot there is - I found doing 80 mph in 6th wouldn't quiet achieve this ( it started regen then stopped, started then stopped) so you'd need to be in a lower gear at higher revs to get it to regen.

 

can you please ellaborate on this? 

The DPF temp varies (under normal circumstances) when driving according to engine rpm/load (and maybe other factors that I'm unaware of).  If The missus was driving at a steady 80 mph in 6th the DPF temp was showing around the 320 deg mark.  The temp does fluctuate a bit but what I noticed was if it got over 330 deg the car would naturally start to regen (shown by the DPF icon changing colour in the VAG DPF app when being used in real time mode).  But as it's fluctuating I was seeing the car start to naturally regen (regardless of soot level) but then stop again as the DPF temp dropped below the 330 deg mark. 

 

So if you were diving at 80mph in 5th I'd expect the DPF temp to be higher than it would in 6th gear and id expect the car to regen naturally regardless of soot level - I've not tested the theory so his isn't gospel!

 

The only reason I started monitoring the DPF was after a 2 hr journey At 80 mph early one morning (with cruise set) stopped at the services and auto start stop disabled itself - turned car off and the fans were on and it stank of burning rubber.

 

As a side note, We were doing 70 mph with cruise set and the soot level reached capacity so the car forced a regen and he DPF temp increased from about 310 deg and went up to 650 ish.

 

like I said before, monitored it for a few weeks and it is what it is, it does what it does.  If its in the middle of a regen when I finish a journey I run it off, I don't wait - I wouldn't drive it in a manner to try to get it to regen as it will do it when it's ready.  The only annoyance is I know it will use fuel when it's a forced regen but I don't know how much fuel.  Suppose it will vary on a number of factors.

 

Maybe buy one of the readers, they are about £18 and £3 for the proper VAG DPF app and see for yourself.

 

hope this helps

How long/far does a full 24g to 4g regen usually take?

 

The shortest distance I'd drive my Skoda diesel would be my commute at 27 miles with 20-odd miles ~20 minutes at motorway speed. Anything shorter we'd drive our EV. I've never bothered to do anything to help regen. From VW DPF app, everything seems to be going well. Whenever I plugged it in, it reads anything in between sub-10g and 20-something.

 

 

@ScoutCJB, I have bought the app and monitored it. However nit on long journeys as the OBD adapter is need my knee and I risk to push it. So I was not aware of the 330C threshold for passive regen.

 

Thanks

Reading through how the DPF works has made me realise that I did not sufficintly consider my usage profile. I changed from 2002 VolvoV70 to 2015 Skoda diesel thinking that I would get like-for-like comfort at a better economy.

 

l use the car maybe every other day (the only driver) for 2m trips and occasional once a month 60m, I totally failed to see that this was at odds with what modern diesels are for!  Nobody explained this -- but then I didn't even ask.

 

I assume that my driving pattern will knacker the car sooner rather than later?

 

 

 

Edited 23 May, 20188 yr by kenppy

On 5/21/2018 at 22:30, seanbrady49 said:

Shame you cant use VCDS to code the light to come on when a regen is active and off when it's finished.

Skoda would have been 'simply clever' to have enabled an option on the car to highlight regen in progress.

Agreed, I've come from a Peugeot 407 and it used to turn on the heated side mirrors when doing a regen , does the Skoda do this ?, so you could stick out your hand and check the mirror was warm. Some people wired a little led to the wires going to the mirror so it illuminated when the mirrors were warming so you knew it was doing a regen.  

4 minutes ago, lway said:

Agreed, I've come from a Peugeot 407 and it used to turn on the heated side mirrors when doing a regen , does the Skoda do this ?, so you could stick out your hand and check the mirror was warm. Some people wired a little led to the wires going to the mirror so it illuminated when the mirrors were warming so you knew it was doing a regen.  

wow

 

Never thought of this. Sounds logical to put more load on the engine, but honestly not very close to the mind. 

 

Interesting, if someone finds it please share

9 hours ago, wyx087 said:

How long/far does a full 24g to 4g regen usually take?

 

The shortest distance I'd drive my Skoda diesel would be my commute at 27 miles with 20-odd miles ~20 minutes at motorway speed. Anything shorter we'd drive our EV. I've never bothered to do anything to help regen. From VW DPF app, everything seems to be going well. Whenever I plugged it in, it reads anything in between sub-10g and 20-something.

 

 

 

Ive never totally monitored it and it will depend on driving style but I think at motorway speeds of 80 mph in 6th gear it's about 20 - 25 mins from 24g to 4g.  In different gears at higher rpm it may burn a little quicker but I never got round to testing that theory.

 

8 hours ago, TTodorov said:

@ScoutCJB, I have bought the app and monitored it. However nit on long journeys as the OBD adapter is need my knee and I risk to push it. So I was not aware of the 330C threshold for passive regen.

 

Thanks

 

The adapter I bought was a Bluetooth one and quiet small so you can't even see that it's plugged in.  The 330 deg c temperature was what I saw on my 2.0 manual Scout ... I'm assuming it's simalsir on other models

15 hours ago, lway said:

Agreed, I've come from a Peugeot 407 and it used to turn on the heated side mirrors when doing a regen , does the Skoda do this ?, so you could stick out your hand and check the mirror was warm. Some people wired a little led to the wires going to the mirror so it illuminated when the mirrors were warming so you knew it was doing a regen.  

Heated side mirrors turning on during a regen sounds a totally random association to me, the 'extra loading' on the engine would be minimal.

I'll put that piece of info in my "awaiting further confirmation" mental folder  

1 hour ago, Gerrycan said:

Heated side mirrors turning on during a regen sounds a totally random association to me, the 'extra loading' on the engine would be minimal.

I'll put that piece of info in my "awaiting further confirmation" mental folder  

 

Yeah, but it was a Peugeot...

 

Knowing their electrics, it probably turned the heated seats on when you reversed 

1 hour ago, Gerrycan said:

Heated side mirrors turning on during a regen sounds a totally random association to me, the 'extra loading' on the engine would be minimal.

I'll put that piece of info in my "awaiting further confirmation" mental folder  

 

All I can say is it comes from 8 years of owning a 407, getting the DPF cleaned twice and replaced once and lashings of Dipetane, ultimately it was the cost to replace the DPF that outweighed the value of the car that led me to move to an Octavia.

You could say i'm familiar with Peugeot DPF issues .

 

Here's a quote from the Peugeot forum if you still doubt me:

To increase the exhaust temperature the car chanages the injection timing and places additional load on the engine by activating the glow plugs and the heated rear screen.
When the heated rear screen is on so are the heated mirrors. If you put an LED across the mirror heating terminals then you effectively create a warning lamp for when a regen is in progress.

 

Link to forum: http://www.peugeotforums.com/forums/407-41/dpf-common-issues-205826/ 

15 minutes ago, pist0nbr0ke said:

 

Yeah, but it was a Peugeot...

 

Knowing their electrics, it probably turned the heated seats on when you reversed 

 

Lol, true, had a few niggles with that car alright but the engine was sound did 380,000 km before the cost of fixing the DPF outweighed the value of the car, considered getting it mapped out and removed but it was time for a change anyway.

 

Interesting that the Skoda doesn't use an additive to help the DPF regen. Was chatting with the dealer when I bought it and he reckoned Skoda were going to go down that route at some time in the future, can anyone confirm this ?

11 minutes ago, lway said:

 

Lol, true, had a few niggles with that car alright but the engine was sound did 380,000 km before the cost of fixing the DPF outweighed the value of the car, considered getting it mapped out and removed but it was time for a change anyway.

 

Interesting that the Skoda doesn't use an additive to help the DPF regen. Was chatting with the dealer when I bought it and he reckoned Skoda were going to go down that route at some time in the future, can anyone confirm this ?

 

Yeah, had a 2006 307 1.6HDi for work myself, put nearly 100k miles on it in 2 years. Whilst the interior fell to bits and there were a few random electrical gremlins, it was okay to drive, economic, comfortable, and never actually let me down!

 

Regarding DPF additive, if you mean adblue, it's used in the 190ps SCR engine, but that's not fitted to the Octavia. As I understand it, adblue is not used to help the DPF regen, but rather to neutralise nitrogen oxide emissions.

 

Currently, Skoda have withdrawn the vRS TDi from sale, and speculation is that they will have to introduce adblue/SCR to meet the new WLTP/real life emissions tests due in September, so we may see the 190ps engine become available in the Octavia.

9 minutes ago, pist0nbr0ke said:

Regarding DPF additive, if you mean adblue, it's used in the 190ps SCR engine, but that's not fitted to the Octavia. As I understand it, adblue is not used to help the DPF regen, but rather to neutralise nitrogen oxide emissions.

 

Yeah that's the stuff i've heard about. The Pug used Eloys fluid to help the soot burn off during regen, interesting to know that Ad Blue is a different idea. Must do some looking in to how the Skoda regen operates.