DPF Regen at Idle

[savedbythebell]

Quick query about DPF regen, I am fairly familiar how it works and never had the DPF light lit.

However when you come to complete a journey and a DPF regen is taking place ( increased idle rpm ) can I just let the car idle until it finishes ? Is this state enough to reach the correct parameters for the regen to finish? OR should I do the usual and drive it over 50mph with revs at 2200 ish?

Thanks!

 

[Dorny]

If the light is on, then it is pretty blocked up. You can try doing some motorway driving to it get nice and hot. Or you can go to a garage and they can use their diagnostics machine to perform a manual regeneration. And failing those two its either new DPF or taking it off and getting it cleaned.

The car being stationary and you keeping up revs is dangerous and some cars don't allow regen to happen during that. You can only do it stationary when performing a manual regeneration with a diagnostic machine and you have to be careful what is behind or under the car as the exhaust gets very hot.

 

[savedbythebell]

Hi,

Let me clarify,

The DPF light is not lit and never has been to date.

During a DPF regen the engine idles automatically at slightly higher revs as part of the regen process. My question is can I let it sit like this until it completes ( which it always does ) or should I be taking it out for a spin at over 50 mph and 2200 revs?

Cheers!

 

[Dorny]

Better for you to take it out for a spin, better on motorway or dual carriage way. The hotter the exhaust gets the better at regenerating.

 

[Mk3 Se]

When we had our diesels with a DPF (not a Seat) if we spotted it carrying out a regen when we were due to stop we would try and continue until it completed. Doubt it would complete at idle since it requires some load on the engine and most manuals clearly state you need to be going over a certain speed (our was 37 mph).

The first one we had would continue the next time you drove it (once it was up to temp) so not really an issue if you stopped but the second could wait days before it tried again and that would normally be at an inconvenient time.

Guess all manufacturers set them up slightly differently.

 

[savedbythebell]

You might be right, it happened today as follows.

Arrived home, dpf regen taking place indicated by increased idle rpm. ( also note I just filled the tank and typically this is when it occurs once it reaches operating temperature after a fill )
Waited for about 10 - 15 minutes then it stopped and the engine auto shut down with no fans running at full blast to indicate a regen was interrupted.

However I started it up again 1 minute later ( as it was up to temp ) and noticed it was idling high again so I presumed it was still trying to do a regen.

I took it out for a 15 minute spin and when I got back it was back to normal, so perhaps yes letting it finish at idle does not work.

 

[JK1]

I'm sure I read somewhere that if the engine is operating for 10 minutes outside of conditions needed to do a regen (e.g. idling, crawling in traffic) it will give up and try again later.

Don't think it mentions it in the manual, but there was a VAG Diesel engine tech document that went in to some detail about the process.

 

[savedbythebell]

That would make perfect sense so to what I have seen, cheers, so take it for a spin is the answer

 

[DEAN0]

I believe that a regen will not happen if the fuel light is on in order to conserve fuel.

 

[Dt-spd]

If it's regen'ing when you come to the end of your journey I would recommend just turning off and carry on with your day.

Leaving it to finish a regen at idle is the worst case as you have a lot of heat but not much exhaust flow. This is called a drop to idle event and is one of the worst things a DPF can go through as it can cause localised hot spots on the DPF which are not ideal.

If you just stop the engine then the regen will resume next time you drive.

Alternatively, you could just go for another drive until its finished, that's what I tend to do in my car.

 

[DEAN0]

Alternatively, you could just go for another drive until its finished, that's what I tend to do in my car.

This would be so much easier if the clowns had thought to put a "Regen taking place" warning light on the dash so you could carry on and let it finish.

 

[Dt-spd]

This would be so much easier if the clowns had thought to put a "Regen taking place" warning light on the dash so you could carry on and let it finish.

Yeah I agree, other cars are starting to get a "DPF Clean" message so maybe Seat will catch up. I would be quite happy to have a "current soot level" reading as well so I can monitor DPF soot levels, but maybe that's just me

I find it fairly easy to spot it's in regen, raised idle is the main one but there are some torque drops at tip out and a change in combustion noise etc.

 

[MyLeon]

This would be so much easier if the clowns had thought to put a "Regen taking place" warning light on the dash so you could carry on and let it finish.

^ exactly!


2015 Leon ST FR 184 DSG

 

[stu_m]

http://www.seatcupra.net/forums/showthread.php?t=263734

 

[concerned cat]

Thanks for some sanity on the forum stu-m.

DPF seems to spook so many people on here.

It's quite simple, & not rocket science. How many people have had the DPF warning light?

 

[stu_m]

I'm not worried about mine and most of my driving is commuting to and from work! it gets a decent run every few months at least!

never seen a DPF light on and to be honest I dont expect it to come on any time in the future of my ownership!

 

[savedbythebell]

Great info as always guys, appreciate it