D5 (2005 on) Longer runs but more DPF regenerations - underlying issue?

[5cilinder]

Originally Posted by Proghound

Most times when regeneration starts it's been doing 55mph or more for at least a couple of miles. I didn't get to do that on my old commute but now I get two stretches on my 21 mile journey where that happens.

So could that be the answer? That it's checking every 200 miles or so, finding that conditions are favourable to regenerate nearly every time, and starting the process off? And on the old commute, it would more often find that it couldn't, and go back to sleep for another 200 miles?

I think the regenerations are also shorter now than they were. Seems like it takes 12-15 miles - maybe 20 minutes? I can remember some times last year that might even have been double that. Mostly the regenerations are completed every time now - it carries on even if I have to drive at less than 40mph for a while - I guess it would stop eventually but I'm not usually held up through villages for that long.

If you dont do highwayspeeds the regeneration is suspended until its aprox 1000km and then its forced highway or not wich is long interval long regeneration
If after 500 km highwayspeeds are reached than regeneration is started because of the favoureble condition (higher engine baseload less after injection)
and because of the less soot accumulated thusfar the regeneration time shorter with the shorter interval
Those distances will be slowly reduced with ashaccumulation along the years
Regeneration is measured in time not distance ,if you drive very fast the enginebaseload is higher with more heat but the afterinjection is toned down to keep a steady temperature

[skyship007]

Originally Posted by Proghound

On a D5? Lifetime of the car. No ash buildup to clog it up and require replacement, because no EOLYS additive is used. I've read on here of ones with 200k or 300k miles and no DPF issues.

I'm sure the motorway users that have well maintained engines are good for a lot of miles, but a lot of Volvo owners that short trip and have a higher oil consumption for various reasons do run into DPF warning issues. If I owned one it it gave a warning, I might be tempted to remove it, although that is an MOT failure point and not exactly friendly if you spend time stuck in city traffic etc:

http://www.sinspeed.co.uk/volvo-xc70...moval-session/

Some Volvo diesels do have a service interval listed for the DPF, but I can't find which ones at present, although I was stunned to read that the DPF in a D5 (It might be early models only) is not included in the warranty:

http://www.practicalcaravan.com/foru...ill-the-diesel

You might be able to bodge the job with a short lasting Fleabay part for 500, but anything with a warranty is 1500 and the real McCoy Volvo job seems to be about 2500 quid, although that must include a CAT and EGR I presume.

[Proghound]

Originally Posted by 5cilinder

If you dont do highwayspeeds the regeneration is suspended until its aprox 1000km and then its forced highway or not wich is long interval long regeneration
If after 500 km highwayspeeds are reached than regeneration is started because of the favoureble condition (higher engine baseload less after injection)

That's sounds very like what I've been experiencing, except that the distances are more like 300km and 600km for me.

So if I understand you correctly, after whatever distance interval when it first becomes eligible for regeneration, there must be a range (perhaps 80km?) where it's looking for highway conditions in order to start regeneration. If it doesn't get them during that range, it waits for that distance interval again before forcing regeneration.

I know there's a pressure sensor in the DPF as well to measure soot buildup. Does that have any control over when it starts a regeneration (i.e. at some minimum level of buildup once the first distance interval is reached)? Or is the sensor only there to tell the system when the soot has all gone so it can stop regenerating?

[Proghound]

Originally Posted by skyship007

Some Volvo diesels do have a service interval listed for the DPF, but I can't find which ones at present, although I was stunned to read that the DPF in a D5 (It might be early models only) is not included in the warranty:

You might be able to bodge the job with a short lasting Fleabay part for 500, but anything with a warranty is 1500 and the real McCoy Volvo job seems to be about 2500 quid, although that must include a CAT and EGR I presume.

The car is already out of warranty, it's over 5 years old now.

Those prices for replacement DPFs are frightening. At under 40k miles, I guess I'll be OK in normal use for 5 or more years if I do 20k miles per year, but after that it would definitely be uneconomical to repair if I ran into DPF problems.

With the roof mechanism being another very expensive thing if it fails, I bet the C70 will be an extremely rare sight in another 10 years. They're not exactly common now.

[5cilinder]

Originally Posted by Proghound

That's sounds very like what I've been experiencing, except that the distances are more like 300km and 600km for me.

So if I understand you correctly, after whatever distance interval when it first becomes eligible for regeneration, there must be a range (perhaps 80km?) where it's looking for highway conditions in order to start regeneration. If it doesn't get them during that range, it waits for that distance interval again before forcing regeneration.

I know there's a pressure sensor in the DPF as well to measure soot buildup. Does that have any control over when it starts a regeneration (i.e. at some minimum level of buildup once the first distance interval is reached)? Or is the sensor only there to tell the system when the soot has all gone so it can stop regenerating?

The 500km/1000 km distances are theoretical with a new dpf with no ash
During the years that upper limit will shrink due to ash accumulation wich replaces soot accumulation space

The minimum distance (theoretical)is 500 km but driving conditions/ soot produktion are also limiting factors
In your case the minimum interval is aprox 300 km and is calculated with the distance travelled ,ash sofar accumulated (computerguess lineair with distance) pressure difference across dpf (sootaccumulation +ash) and fuelamount consumed and some educated gues of passive regeneration if the catalyst is above 400 celsius (high load driving)

The pressure sensor is used to determin if the soot is burned (lower pressure difference) but with callibration of the ash accumulation to factor in lasting pressure difference due to unburnable ash

Dpf 's are not required to replace despite waht the stealers are claiming ,dpf's can be vibrated en compressed air contra direction emptied of ash after the soot is burned because soot blocks of the channels wich all truck dpf's standard do in special automated machines , but can be done with your own dpf with common sense diy

[Proghound]

Originally Posted by 5cilinder

The 500km/1000 km distances are theoretical with a new dpf with no ash
During the years that upper limit will shrink due to ash accumulation wich replaces soot accumulation space

The minimum distance (theoretical)is 500 km but driving conditions/ soot produktion are also limiting factors
In your case the minimum interval is aprox 300 km and is calculated with the distance travelled ,ash sofar accumulated (computerguess lineair with distance) pressure difference across dpf (sootaccumulation +ash) and fuelamount consumed and some educated gues of passive regeneration if the catalyst is above 400 celsius (high load driving)

The pressure sensor is used to determin if the soot is burned (lower pressure difference) but with callibration of the ash accumulation to factor in lasting pressure difference due to unburnable ash

Dpf 's are not required to replace despite waht the stealers are claiming ,dpf's can be vibrated en compressed air contra direction emptied of ash after the soot is burned because soot blocks of the channels wich all truck dpf's standard do in special automated machines , but can be done with your own dpf with common sense diy

OK, I think I now fully understand what's going on. It sounds like I don't have increased soot production, but the car is able to take advantage of my more frequent longer runs to initiate regeneration after a lower mileage when there is less soot to burn off. Thank you for all your very informative help with this one :-)

[5cilinder]

To be sure you need to observe that the regeneration time is shorter with a short interval to exclude extra soot produktion
Try torque to precisely see when and whats going on

[nikk530d]

Proghound,
was there any problem with your car or everything is fine? I have the same issue with my dpf as you and would like to know if this is normal? Or you found some problem afterwards...

[5cilinder]

He had no problem, it functioned like it should .
If he still tought he had a problem he would asked again

[nikk530d]

When you read the net, you can only find that more motorways driving results with longer regeneration intervals and vice versa. When I was reading Proghound's posts I felt like reading my own words.
So, everything is exactly the same, even the distance we cover every day (20 miles). The only difference is the car (my is Bmw 530d 2007). I also checked my car with diagnostic software with no faults appearing. It's interesting that the backpressure is always very low, even when the regen process starts. But it seems everything is fine then, the car just takes the advantage of my driving style.