time since last regen min

apptester
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time since last regen min

Post by apptester » Wed May 06, 2020 12:13 am

Hi,
can you please clarify what this means?
- time spent driving the car
or
- time in general ?

it says 456 min, which is 7.75 hours so I am guessing it can only be time spent driving .

Previously scan done by vcds has shown last regen time in minutes and seconds which calculated to 60 days and oil ash value was 0.05 l so I am confused trying to understand vag dpf oil ash residue presentation in different units.


thanks

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Re: time since last regen min

Post by admin » Wed May 06, 2020 1:34 pm

"Time since last regen" is running time, it doesn't increase when the engine is off.
You can easily verify this checking the value just after the engine power off and just after the next engine start (after hours or days): the values are identical.

I don't understand your question about oil ash ... you see different units between VCDS and my app?

apptester
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Re: time since last regen min

Post by apptester » Thu May 07, 2020 12:51 am

yes the VCDS scan has shown oil ash value of 0.05 l which I was told was good indicator, but I am trying to compare that against oil ash residue= 22.1 g as seen in VAg DPF app.
I am struggling to understand are these similar indicators and how can a value of 0.05 l can be translated to different units (grams) ?

thanks

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Re: time since last regen min

Post by admin » Thu May 07, 2020 8:16 pm

Ok clear.

In some ECU I found oli ash value both in grams and liters. I usually prefer to display the value in grams because it's more precise.
The factor between the two units is 400: to translate your value in liters you have to multiply by 400.
As you can see, the value 0,05 l corresponds to 20 grams, but my app shows 22,1 grams. This is the reason why the value in grams is more precise.
Is just a finesse, maybe useless, but being able to choose I preferred the better value in grams.

apptester
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Re: time since last regen min

Post by apptester » Fri May 08, 2020 10:39 am

thanks, I watched regen in progress last night, it took 14 min to complete, car was parked and I noticed idle rpm going up to 1k as it started and when finished it was back to normal 750 rpm.
Soot mass after regen is 15.09 g and oil ash 22.2 g .
dpf gas temp was nearly 600 C.

can you predict how many miles is left in this dpf filter before it needs deep ultrasonic cleaning ?

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Re: time since last regen min

Post by admin » Sat May 09, 2020 10:16 am

I don't have experience in aged filters. You may ask to some real expert.

The regeneration described in your post was probably interrupted before its natural end because the finished value is too high, it should be between 2 and 8 grams depending on the driving style in that moment.
You can easily verify this: if you still see the little red dpf and hourglass icons next to the filter image, the regeneration was not completed. It isn't a big problem, it will restart when the ECU will find the ideal conditions or when the soot value will reach about the 100% of filling.
When possible, you should avoid standstill regeneration, the process produces thermal stress to all components and with a poor ventilation, all components will reach higher temperature than with car in movement. This is just an advice.

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Re: time since last regen min

Post by apptester » Sat May 09, 2020 2:27 pm

thanks for explanation, just to confirm "the finished value is too high, it should be "soot mass calculated" or something else?
yes, the regen has not yet completed (red hourglass visible) because next day regen duration said 17 min and soot mass was higher at 16.99, also progress bar was at 72%. (is this really a regen progress bar ?)

So I am still confused, a bit less than before though but when I saw engine idle going back to normal I thought regen was complete, so idle rpm alone is not a good indicator. One would think following some kind of logic that regen process has finished when idle is back to normal.


Obviously not because the engine ecu has a mind of its own. Unless it has a fault. Which I need to know about, as dealer warranty expires soon.
Seems like this car is in some kind of never ending regen loop and my patience is running thin. So much that I wished I bought a petrol car instead.
Screenshot_20200509-185544_VAG DPF.jpg
Last edited by apptester on Sat May 09, 2020 9:34 pm, edited 1 time in total.

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Re: time since last regen min

Post by admin » Sat May 09, 2020 9:28 pm

If you let perform the regeneration standstill, the ECU could decide to interrupt it because it knows you are standstill and this could be the reason why you see the rpm decreasing.
If you want to use the app to verify, you have to check the post injection values: when they fall to about 0 the regeneration is finished (finished means that the ECU decided to stop it, not that the soot mass value is low enough).

In my personal experience, I had regeneration standstill just 2 times with regular finishing, but this doesn't mean every engine must do the same.
I don't know exactly what parameters the ECU uses to start and stop the regeneration, but I think the temperatures and the time are the two most important.
In my 2 cases described above, I completed an almost finished regeneration so the car was standstill only few minutes and not for the whole regeneration.
In your case your regeneration started from an high soot mass value?

apptester
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Re: time since last regen min

Post by apptester » Sat May 09, 2020 9:46 pm

post injection values shown in updated picture are both at 0.00, and yet, red hourglass is still showing regen is pending, if I am not mistaken.
How could this be?
Contradiction ?
I would like to know if forced regen will bring soot value to minimum and would the dpf benefit from cleaning ?
I am tempted to break this annoying cycle of never ending regeneration. Either a forced regen or dpf clean.
Last edited by apptester on Sun May 10, 2020 8:34 pm, edited 1 time in total.

apptester
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Re: time since last regen min

Post by apptester » Sun May 10, 2020 8:33 pm

admin wrote:
Sat May 09, 2020 10:16 am
I don't have experience in aged filters. You may ask to some real expert.

The regeneration described in your post was probably interrupted before its natural end because the finished value is too high, it should be between 2 and 8 grams depending on the driving style in that moment.
You can easily verify this: if you still see the little red dpf and hourglass icons next to the filter image, the regeneration was not completed. It isn't a big problem, it will restart when the ECU will find the ideal conditions or when the soot value will reach about the 100% of filling.
When possible, you should avoid standstill regeneration, the process produces thermal stress to all components and with a poor ventilation, all components will reach higher temperature than with car in movement. This is just an advice.
"The red hourglass icon means that a regeneration process is pending" > from your other post on this forum.

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Re: time since last regen min

Post by apptester » Sun May 10, 2020 9:22 pm

Strange 46 err displayed during regeneration cycle in top part of screen.
Any idea what it means ? it does not show always.
Screenshot_20200507-195706_VAG DPF.jpg

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Re: time since last regen min

Post by admin » Mon May 11, 2020 11:29 am

Sporadic errors could appear, they first depend on the adapter quality and sometimes also on the radio disturbances.

About the pending regeneration: your filter can stay in a temporary condition if the regeneration is interrupted (for different reasons). When this happens, the ECU evaluates if next time you start the engine it's necessary to restart the regeneration process. It's not mandatory, if the soot mass value is not so high, the ECU can decide to wait for next filling to reduce the number of regenerations.

Normally the regeneration starts at 22-24 grams and ends at 3-8 grams; if for any reason it stops for example at 10 grams, it's not convenient to restart the regeneration just to burn 3-4 grams of soot mass, the ECU prefers to wait until the soot will reach again a high value of about 22-24 grams.

apptester
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Re: time since last regen min

Post by apptester » Mon May 11, 2020 2:54 pm

thanks, this explains a lot to me.
Now, what about forced regen, or filter clean? Should I go and apply forced regen using another app with the Carista dongle (still searching for best one), and then do dpf clean, using chemicals ?
This would then resolve the issue of frequent regens, interrupted regens and/or gremlins.

thanks agan

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Re: time since last regen min

Post by admin » Tue May 12, 2020 11:34 am

Unfortunately I don't have experience in clogged PDF filter so I can't advise you about the right way to clean it.

The forced regeneration is similar to the field one, so I think it doesn't give you more cleanliness.
You oil ash residue seems to be low, I don't think it's the time to do a chemical cleaning, but I can be wrong.
If you have frequent regeneration interruptions, you should understand the real cause that can be a faulty component or just your driving style/conditions.

apptester
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Re: time since last regen min

Post by apptester » Tue May 12, 2020 9:34 pm

Another short 20 min drive to work and back. Regen status says pending, according to the picture below.
And there is a value of 110 mg/mile in upper right corner. Not sure if this is calc soot or something else?
As for frequent and incomplete regens ,this is mostly due to short journeys, daily commute is not a long distance motorway drive, unless there is a fault somewhere, but the car had full VW diagnostics recently with no faults found.
Attachments
Screenshot_20200512-150356_VAG DPF.jpg

apptester
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Re: time since last regen min

Post by apptester » Wed May 13, 2020 6:34 pm

Regen now complete, see picture below.
Screenshot_20200513-094144_VAG DPF.jpg
why would the status show 22% after only 3 min since completion of regeneration cycle?

and another one 8 miles or 30 min later:
Screenshot_20200513-094144_VAG DPF.jpg
Attachments
Screenshot_20200513-160005_VAG DPF.jpg

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Re: time since last regen min

Post by admin » Thu May 14, 2020 2:22 pm

The rating mg/km (or mg/min if you set it in the options) is the soot burning rate in mg for every km measured in the last 2km.

The regeneration never finishes at 0%, this because when the filter is almost empty, the grams burned in the time are less than when the filter is full of soot (the soot burning helps to increase the filter temperature, so less soot present means less temperature).
You can see this with the rating described below in this message: when the regeneration starts this value is higher than when the regeneration is going to finish.

The ECU stops the regeneration at a compromise value to reduce the soot mass and to avoid waste of fuel.

For example if you're running constantly at 110km/ and the regeneration starts, you could se a rating of -2500 mg/km at the beginning an -500 mg/km at the finishing of the regen, despite the gas temperature remains at about 650°C. This difference is due to the different quantity of soot in the filter that helps the regeneration.
And if for example this regeneration takes 15 minutes to complete, a process to reach 0% could take 30 minutes (hypothesis), so 15 more minutes of post injections (more fuel consumption) and high temperatures in the engine (thermal stress).

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Re: time since last regen min

Post by Ermi_72 » Sun May 17, 2020 11:08 am

Czy Twój samochód był na akcji serwisowej NOx w 2016r.? Ja wczoraj zmieniłem soft na starszy.
Pierwsza obserwacja:
Produkcja sadzy zmniejszona z około 95mg/min na 30mg/min
Co będzie dalej? Zobaczymy...

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Re: time since last regen min

Post by admin » Mon May 18, 2020 12:09 pm

Ermi_72 wrote:
Sun May 17, 2020 11:08 am
Czy Twój samochód był na akcji serwisowej NOx w 2016r.? Ja wczoraj zmieniłem soft na starszy.
Pierwsza obserwacja:
Produkcja sadzy zmniejszona z około 95mg/min na 30mg/min
Co będzie dalej? Zobaczymy...
Post in english, please.

apptester
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Re: time since last regen min

Post by apptester » Wed May 20, 2020 8:39 pm

he wants to know if the car is affected by 2016 service action (recall to update software), but this engine is not affected, VW check says:
"We are pleased to confirm that your vehicle is not affected by the EA 189 NOx emissions issue."

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