DPF Regeneration Cycle - V40 D4 MY 2014 (5 cyl)
 

I started this thread in the V40 section but probably more appropriate in here.

My understanding is that a regeneration cycle differs from model to model diesel engine so would anyone have "specific" knowledge of what exactly happens during a dpf regeneration cycle for this model engine from start to finish?

Reason being is I feel (though am not sure) that this V40 'may be' misbehaving during the regen cycle.

We have two Volvo diesels in the family; a 2014 XC70 2.4 D5 and this V40 2.0 D4 (5cyl). Both have an OBD2 scanner fitted and we use the Car Scanner App to provide details of the DPF Soot level, and DPF Temperature which allows us to know when the regen cycle starts and so ensure we continue to drive the cars in order to complete the cycle.

The XC70 starts the regen process when the DPF Soot Level reaches 29/30grams (about every 250klms). During this time the DPF Temp fluctuates between 550degC and 675degC. The regen is complete when the Soot Level reaches Zero (about 20klms to complete).

The V40 on the other hand starts the regen process at various stages when the Soot Level reaches somewhere between 26grams and 29grams. It gets up to the same temperatures but never seems to drop down to a zero Soot Level. It will stop the regen process at various stages between 6 grams and 14grams of soot. Not at all consistent, and bloody annoying.

So the ultimate question is...... Is this normal operation on this model engine, and if not, what could be wrong?

I can't answer with specific knowledge of either this engine or this model, but what you describe here in this quote pretty much matches my observation of the regen process on my 2014 V60 with the newer VEA engine (also using the Car Scanner app)... i.e. the soot loading never went down to zero but would stop at an inconsistent (but low-ish) figure. I assumed that it was an 'economy' thing to leave something that hopefully passive regeneration would then deal with and so minimise the active regen burden?

I think expecting the soot level to be reported as 0 is unrealistic.

Consider the honeycomb of a DPF.
The DPF can become blocked due to soot which can be burnt, soot which cannot be burnt, DPF filter pieces which break off, catalytic converter pieces which come from any upstream catalytic converter, and any foreign matter which made it's way through the engine. I've seen pictures off all of the above in various makes and models of vehicles.
The pressure reporting of the DPF is done through the pre and post DPF pressure sensors.
If either of these is not exactly the same as the other, then a pressure differential may be reported which does not really exist

All of these factors means that the estimated soot level of a DPF filter, which is measured only indirectly, being derived from a pressure differential, may not be exactly correct, and may change over the lifespan on the DPF and vehicle.

To determine exactly why the DPF is not going to zero derived soot levels, do the following:

1. Replace both pressure sensors with known good units where you have calibrated them in a laboratory environment
2. Remove and cut open the DPF filter to determine how blocked it is, or, fit a brand new DPF filter which has been tested and measured to have zero pressure differential.

Only after having done the above can you reach any known accurate conclusions.

On a practical note, most people would not be prepared to spend the time and effort and may not have the resources to do the above, and thus may choose to live with the current DPF characteristics.

In other words, accept that imperfections exist and get on with life :)

Thanks for your reply. Reassuring that I'm not the only one to experience this. Hopefully it is 'normal' behavior, although it does seem a bit strange that the regen doesn't clear the dpf completely of soot.

check the egr valve it needs to be in perfect working order to allow regens

Thanks for that. Will get it checked out.
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Hi guys, quick question here, my 2012 D5 (215hp) regen every 600 / 700km, but it takes more than an hour to do.
sometimes, there is a "dpf regen too long" code that shows up. Now the ECM gave up and dont show any code, even if it takes more than 100km to regen from 25 to 5grams.

any info ?

My D3 163. Can take an hour to do as well.. it has been like this for as long as I remember. Now on 240000km. If I block it in 4th gear and drive for 20 minutes at 3000rpm on a motorway it will generally finish. The instant consumption drops to zero going downhill or slowing down so I know it's finished. It's used for long distances, so I don't always realise it's regenerating. If I'm near home I follow the 4th gear procedure. So far no lights or messages. I guess it's quite full of ash now as it regenerates more frequently now.

another thing to consider is how hard the vehicle is driven ie how much soot / ash is blown out during the dpf regen no two drivers are the same or the difference of journey type / or distance there are so many variables . if both cars are working and showing no faults just keep driving. them . the volvo dry dpf system is very good .don't over think it

V70 D3 DPF Regeneration recorded
 

Small contribution to this thread as it deals with DPF regen with similar engine.

https://www.volvoforums.org.uk/showp...&postcount=400