DPF filter nightmares

[waynne]

I'm reading more and more horror stories about DPF filters!

It seems that manufacturers have fitted them to help improve the emissions around town but if all you do is drive round town they never get cleared out.

Audi salesmen are trying to get people off the Diesels where possible as they are getting lots of complaints and issues about them.

Is removal of the DPF an option? Does a car with DPF removal still pass a MOT? How strict is the emissions test and will a remap help to keep the DPF clear?

(Replacement costs around £2000 are a nasty hidden expense on a 30,000 mile engine.)

[HDi fun]

The DPF in my car was replaced due to it (engine, not DPF) being filled with the wrong oil. Cost was only about £300. A remap will help keep it clean - higher exhaust temps.

Removing is difficult but not impossible but you'll need to do some extensive ECU recoding.

The best solution is to drive it hard every couple of weeks.

[pgarner]

it can be coded out in the audi. many tuners offer this as some have been finding that the DPF gets clogged up even quicker after mapping. esp if its only driven small distances

[waynne]

I presume it would need to be removed if it is coded out? I can't see makers doing anything sensible like fitting a wastegate control to the DPF?

[HDi fun]

Originally Posted by waynne

I presume it would need to be removed if it is coded out? I can't see makers doing anything sensible like fitting a wastegate control to the DPF?

It might transpire that they will be forced to fit some bypass mechanism if customers have repeated problems.

You wouldn't code it out unless you are removing it - there would be no point and it would clog quickly as it would not go into regeneration mode.

Regeneration is crucial to correct operation of the DPF. What I'm getting at is that it's fine for it to clog provided it's allowed to regenerate periodically.

I did write a great big chunk on these for the idiot Stevieboy. I'll see if I can find it and forward it to you. If I can't I'll write out the whole operating principle of these for public consumption.

DPFs aren't the evil some paint then to be.

[pgarner]

they are in the audis lol

yes they are removed. if you can keep an eye on the % the DPF is at then you can get it forced regend. ( i think this can be done through VCDS so could be a worthwhile investment ) if it reaches 70% clogged then its a bin and new one job. i think they are supposed to try and force themselves clear when they get around 40-50% and people then moan that they have bad economy because of the extra diesel getting burnt trying to get the dam thing hot enough to burn the soot off

[HDi fun]

They usually regenerate every 400-500 miles depending upon driving conditions. Normal regeneration takes about 10-12 minutes so clearly if the car only ever does tiny journeys then it will clog.

But if that's the case then buy a petrol car with a tiny engine - it won't matter if you're only driving at town speeds.

The occasional Turin workout cures all manner of ills of this type.

[waynne]

You did a handy article on DPF's a while back http://www.torquecars.com/tuning/particulate-filter.php if there are anythings to add please let me know and I'll get it updated.

It's quite popular so I'm sure lots of people are having trouble with them.

[HDi fun]

I do vaguely remember authoring that one. The technology has moved on a bit now and some systems are no longer reliant upon the Eolys (copyright Rhoda, formerly Rhone-Poulenc) or other bespoke additives.

Time has shown that the earlier additive dependent systems (such as that fitted to my Peugeot) have proven to be less problematical and less prone to clogging than the later systems.

Should I re-write to cover later systems in more depth?

[waynne]

Yes please HDI, a part 2 perhaps would make more sense but go into as much detail as you want. That would be fantastic,

Incidentally so far your Diesel articles have been read....

132,309 times Filtered for pages containing diesel-tuning.php
34,614 times Filtered for pages containing particulate-filter.php

Which I think is pretty good going. If you feel inspired to cover any other subjects I'll be very happy to include them as well

[HDi fun]

OK, thanks for the note of encouragement. I'll do some additional research into the cutting edge technologies as well to make sure it's definitive, comprehensive and factual. I am a great advocate of checking my own sources and references.

[jarrus]

What I don't get is that manufactures fit these in aid to reduce harmful particulates being released into the atmosphere.
There is a better way of dealing with such problems such as unburnt diesel particulates and the ever tightening EU legislation on emissions for diesels and well all modern vehicles.

LPG! seriously why hasn't any manufacture ran LPG with there diesels?
Most diesel engines are suitable for conversion. When a diesel engine is converted to run on LPG, nitrogen dioxide emissions are reduced by 80% and particulates by 90%, whilst carbon monoxide emissions are reduced to levels well below those specified by the Health & Safety Executive.
And also lets not forget the massive power and torque gains you can get while running partly on LPG.
Buses, lorries, heavy machineary have been doing this for years and some of those vehicles don't even use propane (like most filling stations offer) they use things like waste methane which is a by product of processing our rubbish.

Seriously now, it's not like they will need to spend millions implementing such things as all of the testing and research has been done, yes it will mean you will have to fill up with 2 different fuels but look at the potencials savings (anywhere from 10-25% saving in fuel costs) I would say they small hastle is something I would live with.

[jarrus]

Also I forgot to mention that because you are getting a more complete burn in the combustion process. You aren't diluting the oil as quick as you would running on diesel alone so you wouldn't have to change your oil as often which can be a blessing on tuned diesels as they can emit quite a lot of black smoke (unburt diesel)
Also you can benefit from lower road tax from running LPG.

[WLBjork]

I'll have to disappoint here, I reckon I've read those pages 4-5 times each - if not more

[jarrus]

Originally Posted by WLBjork

I'll have to disappoint here, I reckon I've read those pages 4-5 times each - if not more

Eh?

[waynne]

The figures are for Unique visitor page views. It will only count as unique if you are on a different machine and look at the page!