DPF regeneration process

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duncho
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Post by duncho »

Driving on a long distance journey I got curious of how DPF regeneration process looks like in reality. I connected my tablet, selected parameters I was interested in to see influenced by the regeneration process and started to review soot burn out progress.

I noticed that diesel fuel quality has direct influence on DPF regeneration interval by means:
- Good quality diesel = long intervals between DPF regeneration process
- Low quality diesel = short intervals between DPF regeneration process

While still driving through Germany I noticed that DPF regeneration at regular motorway speed won't necessarily need to be initiated for a long driven distance if quality of fuel is good. Driven from Berlin to Dresden (approx 200km) ECM did not initiate DPF regeneration while engine revolutions was about 2500rpm, (equal to speed 130 - 160 km/h - CVT vehicle) as the soot could burn out naturally during the regular drive (temperature of the exhaust gases is about 400 to 480 °C). During that particular journey, there was about 10g of the soot in DPF filter.

Shortly after I entered Czech republic, I had to refuel the car (MOLL brand diesel) and immediately I noticed difference of soot amount which started to continuously raise. Within the same driving patterns (130 - 150 km/h) the regeneration was initiated after distance of 15 km and the process was repeated approximately each 80 - 150 km depending on driving pattern. During the regeneration process, the temperature of the exhaust gases varies from 630 to 670 °C.

Regeneration process takes about 5-6 minutes at an average motorway speed (100 -130 km/h) and during this time, the entire soot content will be burned out from the moment when regeneration process starts (19g) till end of the regeneration process (i.e. 0.6g of the remaining soot).

If anyone is in need of monitoring when DPF regeneration is in progress, just grab +12V signal from one of the 3 thermoplungers which are designed to put extra load on engine (via alternator) during DPF filter regeneration. On attached video you can see that electric power generated by the alternator increases from 500W to 2.6kW right after DPF regeneration process is started which is followed by THERMOPLUNGER state change from DEACT to ACTIVE.

Video sequence is slightly accelerated to save you your time - regeneration process starts at 1m: 20s



Enjoy watching :)
Last edited by duncho on Wed Aug 29, 2018 5:56 pm, edited 2 times in total.
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gvmdaddy
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Post by gvmdaddy »

How can you measure what weight of soot is in the dpf?
duncho
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Post by duncho »

gvmdaddy wrote: Tue Aug 28, 2018 12:12 pm How can you measure what weight of soot is in the dpf?
You can measure it with a suitable tool which is able to read that parameter from ECM.
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gvmdaddy
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Post by gvmdaddy »

duncho wrote: Tue Aug 28, 2018 12:21 pm
gvmdaddy wrote: Tue Aug 28, 2018 12:12 pm How can you measure what weight of soot is in the dpf?
You can measure it with a suitable tool which is able to read that parameter from ECM.
So in essence it’s not really reading the mass of the soot, more reading the exhaust pressure that is affected by the blocking nature of the soot particles.
duncho
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Post by duncho »

Correct. Therefore I decided to monitor SOOT parameter, which is calculated by ECM comparing pressure of exhaust gasses measured before and after DPF, rather than checking the pressure values. For this purpose it is much easier to see the process of the soot burn during the regeneration.
Last edited by duncho on Tue Aug 28, 2018 5:58 pm, edited 1 time in total.
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Bgmick
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Post by Bgmick »

How are you reading when a dpf regeneration is happening ?
2013 jj10 4wd 1.6 dci
Bgmick
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Post by Bgmick »

I mean what software are you using to read the information ?
2013 jj10 4wd 1.6 dci
duncho
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Post by duncho »

I used Launch X431 Pro 3
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Bgmick
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Post by Bgmick »

I guess there are no basic android apps using an elm327 that can read anything which would point to dpf regeneration ?

Used to be able to read my kia carens 1.7 crdi using torque app by monitoring cat temp and egr % but none of these are avaliable on torque with the nissan
2013 jj10 4wd 1.6 dci
duncho
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Post by duncho »

I doubt there is, but I have no experience with latest ELM327 if there is any. When I tried 4 years ago, it could only read a data you mentioned.
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