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Interesting subject

Posted: Tue Nov 16, 2021 5:38 pm
by Bokucan
Hi experts,

I need some guidence over my dpf situation. First of all i have 2010 VW Golf 2 MT 1.6tdi(CAYC), and my car applies its regeneration process approximetly once a month over 4 years. By this regeneration processes my car does not indicate its dpf warning light or does not show any DTC errors. Once a month my car enters its regeneration mode and after driving with high tachometer use, it turns back its normal operation. For that purpose, i applied cleaning for dpf 6 months ago, it solves my problem a couple of months but after that problem starts again.

Now i have enough of this fight with dpf and i purchased obdII tool and vag dpf app to know my enemy. My current cold motor values are like this.
Ekran görüntüsü 2021-11-16 191454.png
Car's operation is normal right now but the app says it is %74 full. I drived a bit(about 20 km's) and it seems soot mass calc getting up and filter is getting loading.(not a non stop drive, i had to stop the engine for a bit.)
So, is it how it works or my car has some problem with it? (it is getting full->needs regeneration->getting full again->and needs another regeneration)
And by the way what is the limit for soot mass calc values, to which value dpf is considered normal.

Can you help me on my situation please, if you need some data or a non stop drive data for it, i can provide the screenshot in no time.

Just for curiosity and also for learning the behaivor of dpf ,
I did a 50km drive on a highway. I did 100-110km/h on 4th gear(out of 5) with 2500rpm like manual intended of dpf failure
This is the results:

before the drive
After the drive
So basicly nothing is enough to keep dpf maintaining itself, and it HAS TO BE triggered from active regeneration to clean itself. What a shame.

Thanks in advance, and sorry for bad english.

Re: Interesting subject

Posted: Wed Nov 17, 2021 5:54 pm
by admin
I'm not sure to understand all your post, but my first question is: what's the problem you see? In the pictures and in your description I don't read any problem.

Maybe you want to keep the soot mass value stable just driving at high speed/revs? In this case you have to check the gas temperature, when it's high enough, the soot mass production stops or becomes a reduction (passive regeneration). Is this your goal?

Re: Interesting subject

Posted: Thu Nov 18, 2021 12:02 pm
by Bokucan
Hi there,

All I want is to understand the behavior of the dpf. As the app shows me, the soot mass production is directly related to the capacity of a dpf.
If it rises, the dpf is filling up and requires maintenance (active regeneration).

As I know, if you heat exhaust enoughthe temp enough, it burns soot and keeps the dpf clean or operational. (as you guessed it like in your reply)
However screenshots of this test shows that no matter how hard you force passive regeneration is not enough to maintain itself, and eventually it will fail again and start active regeneration process. Constant 100km/h with 2500rpm for 50km should make a differance, but the readings are always went up.

Am I wrong about that though? If it is, how can i avoid active regeneration, and keep my dpf operational longer?

Re: Interesting subject

Posted: Thu Nov 18, 2021 12:58 pm
by admin
Ok now it's clear.

Your analysis is correct, but the 2 possibile regeneration methods differ in the soot burning rate, in fact the active regeneration is extremely more powerful than the passive one.
You can see this taking a loot at the charge rate value (the first on top right) while active and passive regenerations.
The passive regen is very weak vs the active.

There is a speed at which the soot production is 0, so theoretically you could run faster than that speed and reduce the soot mass avoiding the active regeneration forever. But considering the very low soot reduction during passive regen, you should run for hundreds km without stops.
But also in this case, the ECU has a safety function that starts a regeneration if a time or mileage limit is reached. In my car the mileage limit is near 750 km.

Definitely you can't avoid active regenerations, you can only space them out.

Re: Interesting subject

Posted: Fri Nov 19, 2021 10:03 am
by Bokucan
Thank you for your answer.

But this leads up another question on my mind. I bought my car on 2011 and i am using it for 10 years. Last 4 years i have experiencing this dpf regeneration processes( without dpf warning light, if i might add). Before that, i havent experience any side effects of active regeneration. I think i would have notice the tachometer disturbance, white smoke etc, but really i didnt remember such a thing.

If passive regeneration is not enough to keep dpf operational, how come my car did not initiate active regeneration for 6 years. Is it related with dpf material lifespan? If i'll replace with a brand new dpf or get it clean at particle cleaning garages regularly, will it change the regeneration process cycles?

Or as you mentioned in your reply, will ECU force the active regeneration by mileage anyway?

Re: Interesting subject

Posted: Fri Nov 19, 2021 6:34 pm
by admin
In my opinion, it's impossibile that your car didn't regenerate for years.
The standard diesel engine working mode, since DPF exists, includes regenerations. You can be lucky and have them very spaced up, but you can't avoid to have them. I've never heard or read about engines without regenerations.

I think you don't remember regenerations because maybe in the first years the engine was in good health, but now that it's older, the imperceptible effects of the process have become evident. Just my personal consideration.

Re: Interesting subject

Posted: Sat Nov 27, 2021 12:51 pm
by Bokucan
Most probably you are right, i didn't remember regenerations. Anyway, thank you for your inputs, it really helped for my situation. Much appreciated.