Long stop/start journeys effect on DPF?

[VeeFource]

Many websites and common sense say a DPF equiped diesel is a poor choice for short distance journeys, especially involving city driving. But what about if you have to commute a good 45+ mins through a city, does this allow the DPF to regenerate or will it still die an early death? If so wouldn't taxi drivers be complaining more about them considering they spend most of their time in the city?

I can understand it won't help the DPF's lifespan but is it an automotive no no? Can't seem to find any info on this sort of scenario

[addz86]

Usually a car has to be at a certain RPM for a certain amount of time (like on a motorway) for it to re-generate, you can buy things to chuck into the diesel to force re-gen them though

[ShaunTheSheep]

VeeFource said:

If so wouldn't taxi drivers be complaining more about them

They do complain a helluva lot about them! :-) Lost earnings every time they need fettling or replacing.

[Emeye]

Speaking tO cabbies, they prefer petrol engines or older diesels without DPFs. I was told that a local firm was buying up older Saab 95s to use as taxis due to their size and more reliable older tech Diesel engines.

[VeeFource]

Emeye said:

Speaking tO cabbies, they prefer petrol engines or older diesels without DPFs. I was told that a local firm was buying up older Saab 95s to use as taxis due to their size and more reliable older tech Diesel engines.

Hmmmm, that's not a great sign then. So really all these websites & dealers should say "not suitable for short journeys OR any significant amount of urban driving".

[200Plus Club]

We have a 13 plate land rover lwb diesel at work that does nothing but short journeys and the dpf light is on a hell of a lot. We have to let someone take it on a half hr motorway run to get rid of the light. Seems a self defeating device tbh

[VeeFource]

200Plus Club said:

We have a 13 plate land rover lwb diesel at work that does nothing but short journeys and the dpf light is on a hell of a lot. We have to let someone take it on a half hr motorway run to get rid of the light. Seems a self defeating device tbh

Sounds like a bad business buy there for sure!

On the plus side my commute does have 9 miles of motorway so even with 30 mins through town it doesn't seem to regen often (maybe once every 1k that I notice if that) and I've never had the light on. Might take the plunge and buy a proper VAGCOM reader to check the DPF loading. Probably a worthy investment to be sure going back to petrol is worth the innevitable loss in fuel costs.

[cj2013]

VeeFource said:

Hmmmm, that's not a great sign then. So really all these websites & dealers should say "not suitable for short journeys OR any significant amount of urban driving".

I think there's a lot of 'should say...' in marketing, but as long as it isn't 'have to say' it won't happen.

A lot of new cars can initiate regen through diagnostics, so it isn't necessarily a terminal issue, more of a PITA.


Not sure why anyone would buy a DPF diesel for anything other than economic performance or longer journeys anyhow

[Urban Sports]

My 320d does stop start urban commuting of around 16 miles return journey per day, it's on 13,000 miles from new (April last year), I doubt very much it's likely to be an issue in the near future if ever.

[VeeFource]

cj2013 said:

Not sure why anyone would buy a DPF diesel for anything other than economic performance or longer journeys anyhow

Bought mine precisely for those two reasons. I tend to do big mileages at the weekends so DPF clogging with soot isn't a concern for me, but rather the actual lifespan of the DPF from clogging with ash from the city is what I worry about.

I just think it's an interesting debate (and oddly one not often covered) on whether you should still consider diesel for long journeys time wise rather than distance wise. In my experience a warmed up diesel still seems to maintain a good mpg in the city unlike the many petrols I've owned in the past so makes financial sense provided bits don't start to break of course.

Would be great to get the views of any cabbies about this should there be anyon here..

[anonymous-user]

Can you actually tell if your dpf is performing a regen? Can you see, feel or smell anything?

Or is it a case of the light not coming on means it must be OK?

[Drive Blind]

lord trumpton said:

Can you actually tell if your dpf is performing a regen? Can you see, feel or smell anything?

on mine - vw 2l cr tdi - you see an increase in idle rpm from about 800rpm to 1000rpm.

also if you park up whilst it's happening you'll smell it. Its not a full on burning smell but you can tell things are running a lot hotter than normal.

[VeeFource]

lord trumpton said:

Can you actually tell if your dpf is performing a regen? Can you see, feel or smell anything?

Or is it a case of the light not coming on means it must be OK?

Only if I happen to have the torque app running on my phone as then I can see the EGR valve is fully shut at all revs. Mostly though i only notice when I'm sitting at the lights and the idle's high. Sometimes also accompanied by the smell of hot metal if the window's down.

I've read all DPF equiped engines are designed to do an active regen once every so many miles regardless of conditions as a precaution though I don't know if this is true or how frequently if so.

[Jonny_]

Drive Blind said:

lord trumpton said:

Can you actually tell if your dpf is performing a regen? Can you see, feel or smell anything?

on mine - vw 2l cr tdi - you see an increase in idle rpm from about 800rpm to 1000rpm.

also if you park up whilst it's happening you'll smell it. Its not a full on burning smell but you can tell things are running a lot hotter than normal.

It's that odd "very hot metal" smell. Also, from outside the car you'll hear the fans on full bore.

First time my car did it I thought it was about to spontaneously combust!

[anonymous-user]

Generally speaking, DPF issues only occur on the Internet ..

[VeeFource]

Jimboka said:

Generally speaking, DPF issues only occur on the Internet ..

Care to substantiate this?