307 HDI DPF Regen Question

[gumby6371]

Took the little ladies 307 back to the garage yesterday as it was lacking power and giving piss poor MPG's, sure enough it was a blocked DPF.
The car is still under warranty and they fitted a new egr and did a forced DPF regen, checked the additive and reset the clocks all FOC.
When I picked it up he told me to give it a couple of good blasts and bring it back in a week to check it over. Car pulls much better all ready so touch wood it should be running much better by next week.
Here's my question - the guy at the garage said to maintain 3500 rpm for 20+ minutes, only trouble is with the taller gearing I'd have to run it in 3rd on the motorway to avoid john q law giving me a tug. Does a dpf regen need to run at such high revs or can it be done at lower revs for a slightly longer time?
My understanding is that a DPF regen is triggered by egg-sauce temps so a long run at lower revs should have the same affect just take a little longer but I could be wrong?

[Doggy]

It will try to do a regen whenever the dpf differential pressure builds up and you are doing more than about 30 mph with a warm engine.

(When this happens you may hear the heated rear window relay closing every time you press the throttle and dropping out when you take your foot off - that's how I could tell with mine). If you can learn to spot the heated rear window relay thing, you can tell if it's managed a regen by itself.

In many cases it will abort the regen because the car doesn't keep up enough speed for long enough. Problem is it maintains a count of 'failed regens' and when this gets too high, it'll throw a wobbly as you described previously. It's damned difficult to avoid having 'issues' if you mostly drive round town.

It's also been noted that many 6-speeders can't do a regen at legal speeds, because the revs are too low.

I would have thought driving long enough at say 60 - 65 in 4th would do the trick, but more revs / less speed will help. It's trying to burn the soot by starting a diesel fire in the cat. Without Eolys, it needs 500 degrees + to do this, still needs 450 degrees with.

Soon as the warranty's out, kick the FAP out of it.

[OdinEidolon]

I have no problems at all regenerating in 5th at 2000-2300rpm. Of course it takes a while, but I have 1600km/month of motorway just for that.

EDIT: average space between regens is 788km (~500miles), according to pp2000.

[Doggy]

EDIT: average space between regens is 788km (~500miles), according to pp2000.

It starts out at about 1200 km with a new dpf, but reduces as it 'ages', (think exponential decay).

If you're really bored.....http://ftp.psyborg.rpg.pl/hdi/Citroen%2 ... Filter.pdf

[OdinEidolon]

EDIT: average space between regens is 788km (~500miles), according to pp2000.

It starts out at about 1200 km with a new dpf, but reduces as it 'ages', (think exponential decay).

If you're really bored.....http://ftp.psyborg.rpg.pl/hdi/Citroen%2 ... Filter.pdf

I already read that
very interesting stuff.