1 hour ago, OldBoyScout said:

I would like to think that this will not happen with the Skodas, in view of the burning process that takes place when the regen is interrupted.

 

Whilst thankfully it is rare, it has affected a number of older Skoda's in the past. Nowhere near as much of an issue as it was in the Mazda 6 though.

 

I'd just like to take the opportunity to reiterate the fact that DPF's have come on a long way since the thread linked above.

 

DPF's are still susceptible to short, slow speed journey's but thanks to design improvements and the introduction of catalysts, passive regeneration (regeneration during normal driving conditions i.e. no increased rpm or injected fuel) is much easier and therefore more common, meaning short journey's in modern diesels aren't as much of a concern these days.

Sadly even the passive regenerations are not sufficient if your style of drive and type of journey are conducive to clogging the dpf. In my view there should be a minor warning message given on the cars display when the vehicle has gotten to a passive regeneration stage allowing the vehicle to be driven in the prescribed manor to burn of the deposits. Many people believe that racing the car around under hard acceleration will help burn of the build up in the dpf, in fact all that does is create more soot. The correct method is to cruise at a steady pace with the engine revs above 3000rpm with only minimal engine load so that the exhaust temperature is increased but without generating more soot. Meaning car owners could react to the issue during their routine driving. The problem with waiting for the actual dpf warning light to come on (or finishing your journey to find the typical hot burning smell of an incomplete regen') is basically your reacting too late and the passive regenerations haven't been enough or cut short by too short journeys. Short journeys are a major issue running any diesel engine with a dpf equally certain drive styles have the same negative result. For example, perhaps as routine even on longer journeys where you may think dpf will not be an issue, running the car in a lower gear elevating the engine revs to help clear the dpf for a few minutes at a time when the car is fully up to temp will always help keep everything clear. 

The lack of an active regeneration light is deliberate. The car and it's DPF can take care of itself.

 

I can't remember the last time I saw a thread posted on here about an unexpected DPF light. They were plentiful in the days of the MkII Octavia, MkII Superb and Yeti, but since the introduction of the MkIII Octavia and Superb they've all but disappeared.

 

The Kodiaq has been around since 2017, and not one DPF-light related thread. Same goes for the Karoq.

 

If you're driving 2 minutes up the road to the shops and then 2 minutes back and nothing else then you're going to have problems, but as long as the engine is able to reach operating temperature regularly and the AdBlue tank has AdBlue in it then it is unlikely you'll ever see the DPF light.

 

Times change, but peoples (mis)conceptions sometimes become a habit that is hard to shake. The days of taking it for a run up the motorway every few weeks are over.

 

Edited 20 September, 20196 yr by silver1011

The subject here is a Diesel with a 7 speed DSG, 

all this certain rpm stuff is guff, if the DPF blocked light is on all you need is to cover enough miles until things are hot.

Up to 30,000 miles i could do that in 8 miles on local roads, now it takes near 20 miles as the miles have gone on the car, still not 3 years old.

5 days of short trips  of a few miles per trip per day and the DPF light is on.

http://briskoda.net/forums/topic/464465-20tdi-150-dpf-warning

 

Edited 20 September, 20196 yr by Roottootemoot

1 hour ago, Gmac983 said:

 The correct method is to cruise at a steady pace with the engine revs above 3000rpm with only minimal engine load so that the exhaust temperature is increased but without generating more soot. 

 

wow, I haven't seen a turd that big since I worked for Yorkshire Water!

It's no misconception. The last main dealer service I had for my grand picasso earlier this year included the service manager handing me citroens latest info on methods of driving to clear dpf's, applicable to all diesel citroens with dpf's. Also I did say any engine, for example Scania supply engines to Doosan for excavators and dumper trucks etc. Their fitters have a plug in by-pass for the eco mode on their dpf engines to allow them to Rev higher to aid burning of deposits when having regen' issues and that is engines compliant with the latest euro engine regs for off road plant. Whilst I agree that dpf tech has moved on, passive regen is not a new concept. My old 2012 yeti did passive regen but still required to be driven a certain way as well. Even when focusing on the very latest diesel models, the very fact there still is a dpf warning light says that the system can not be truly relied upon to to take care of itself. 

18 minutes ago, SuperbTWM said:

wow, I haven't seen a turd that big since I worked for Yorkshire Water!

 

Please enlighten me o'oracle. 

1 hour ago, silver1011 said:

The days of taking it for a run up the motorway every few weeks are over.

 

I defo wouldn't have trouble with my dpf I had to take my car a run up the motorway. Nearest motorway is a 5 hour drive from my place. 

240 ps vRS DSG just drive the thing, and have the same issue as Caravelle and Amarok drivers.

 

As to Citroens / Renaults / Peugoets and regens, the Dealerships had Taxi drivers sign disclaimers, 

'We know this car will be sh!te as a Taxi the saleperson warned us.'  **But we are leasing as a private car and going to clock it.**

 

2012 are so Defeat Device generation and pre AdBlue in a Yeti, but then some Euro 6 TDI's with SCR still have a nice wee defeat device in them having the AdbLue just sipped.

It will all come out eventually, the 3-4 year old cars will be having more issue soon eniugh.

Edited 20 September, 20196 yr by Roottootemoot

I'd be interested to see a printout from the handbook with the latest diesel engine regarding DPF's. Hopefully not just the normal refer to your service partner stuff. 

 

I'm trying to believe that at 1100 rpm the vehicle can make the exhaust reach 400+ deg temp and incinerate the soot without producing any smoke. Somehow I feel it ought to need a good blast even if it doesn't. 

I think its common practice for a garage to recommend a good thrashing of a car if its had DPF problems, especially ones that cant diagnose the issue that has got the DPF blocked in the first place so clutch at straws and just rag it about or put a brick on the accelerator with it parked up for an hour, 

 

There are millions of people out there that don't know what a DPF is, that are tootling around managing to survive without a DPF light, and they certainly aren't driving about at 3000rpm worrying about soot.

 

Just now, VRS_White_Hatch said:

I'm trying to believe that at 1100 rpm the vehicle can make the exhaust reach 400+ deg temp and incinerate the soot without producing any smoke. Somehow I feel it ought to need a good blast even if it doesn't. 

 

Why would you need it to, if your not driving it, turn the engine off and don't waste your money

3 minutes ago, SuperbTWM said:

Why would you need it to, if your not driving it, turn the engine off and don't waste your money

 

I haven't currently got a diesel, when I was changing my car I chose petrol. I'm trying to understand but so many differing opinions. I used to do regens in a car park while stationary, now that really felt like burning money. I hope they have solved the issue but I wouldn't buy a diesel because my mileage doesn't justify one or do it any favours. A lot of my journeys are sub 5 mile. 

 

38 minutes ago, SuperbTWM said:

they certainly aren't driving about at 3000rpm worrying about soot.

 

Who said I was worrying about anything!? I was merely responding to an earlier post with my views on the subject. Views which are based on facts and logical info I have been given by main dealers (Inc skoda/citroen and Vauxhall). Put simply if everyone who owned a dpf car from the phase when they were very problematic had a pre warning light, it would have been very helpful allowing owners to drive their cars in whatever manner suggested by each manufacturer surely saving one helluva lot of hassle. 

Edited 20 September, 20196 yr by Gmac983

Ah screw it, just drop in a cummins and roll some coal. 

Don't say that, you will awaken the anti-diesel eco warriors!

 

we will have less Nox than a petrol engine once VAG have perfected the quadruple SCR injection prototype!

Edited 20 September, 20196 yr by SuperbTWM

38 minutes ago, VRS_White_Hatch said:

 

I'm trying to believe that at 1100 rpm the vehicle can make the exhaust reach 400+ deg temp and incinerate the soot without producing any smoke. Somehow I feel it ought to need a good blast even if it doesn't. 

Well believe it. 45000 miles in our diesel Kodiaq now with zero DPF issues. We live an hour’s drive from the nearest motorway, and even on a motorway the car never sees sustained driving at 3000RPM. 

 

The occasional forced regeneration at 1000rpm over a 15-20 minute drive or so seems to be perfectly sufficient to keep ours happy. Talk of needing to give them a good thrashing is nonsense applicable to diesels of old. As others have said, thrashing a modern diesel simply uses lots of AdBlue and hastens the need for another regeneration cycle. 

Up here in Caithness you need a wee bit black reek, ken' it keeps the midges doon. 

2 minutes ago, MrTrilby said:

Talk of needing to give them a good thrashing is nonsense applicable to diesels of old. As others have said, thrashing a modern diesel simply uses lots of AdBlue and hastens the need for another regeneration cycle. 

 

Your spot on Sir.

Although the 3000rpm I mentioned wasn't in regards the very latest dpf models with adblu. 

5 hours ago, VRS_White_Hatch said:

I'd be interested to see a printout from the handbook with the latest diesel engine regarding DPF's. Hopefully not just the normal refer to your service partner stuff. 

Kodiaq Owners Manual Page 40 (Page 42 in the PDF version):

 

[DPF symbol] illuminates – the filter is clogged with soot.
To clean the filter, and where traffic conditions permit » , drive as follows for
at least 15 minutes or until the indicator light [DPF symbol] goes out.
4th or 5th gear engaged (automatic gearbox: position D / S).
Vehicle speed at least 70 km/h.
Engine speed between 1800 - 2500 rpm.
If the filter is properly cleaned, the warning light [DPF symbol] extinguishes

 

If the filter is not properly cleaned, the warning light [DPF symbol] does not go out and
the warning light [Pre-heating Unit symbol] begins to flash.
▶ You can drive on, exercising appropriate caution. Seek assistance from a specialist
garage immediately.

WARNING
■ Always adjust the speed and driving style to the actual weather, road, terrain
and traffic conditions.
■ The diesel particulate filter reaches very high temperatures - there is a
fire hazard and serious injury could be caused. Therefore, never stop the
vehicle at places where the underside of your vehicle can come into contact
with flammable materials, such as dry grass, undergrowth, leaves, spilled
fuel or the like.

CAUTION
■ As long as the warning light [DPF symbol] illuminates, one must take into account an
increased fuel consumption and a power reduction of the engine.
■ Using diesel fuel with an increased sulphur content can considerably reduce
the life of the diesel particle filter. A ŠKODA partner will be able to tell you
which countries use diesel fuel with a high sulphur content.

Note
We encourage you to avoid constant short journeys. This will improve the
combustion process of the soot particles in the diesel particulate filter.

 

 

So even the very latest dpf model still requires the car to be driven with elevated engine revs to aid regeneration then (not quite the 3000rpm I was quoting/advised of for older dpf models) but still necessary all the same. 

Also my 2020MY kodiaq handbook states above 2000rpm and at least 60kph for diesel models (so skoda/VAG must be continually updating/revising their data) 

And 3000 to 5000rpm and at least 80kph for petrol gpf cars. 

Edited 21 September, 20196 yr by Gmac983

35 minutes ago, Gmac983 said:

So even the very latest dpf model still requires the car to be driven with elevated engine revs to aid regeneration then (not quite the 3000rpm I was quoting/advised of for older dpf models) but still necessary all the same. 

No. Only necessary if the DPF light has come on and you need to do an emergency DPF clean. Which isn’t necessary unless you do persistent very short journeys. 
 

In normal use, even at motorway speeds, our diesel Kodiaq cruises at less than 2kRPM and never sees journeys where it is driven at a sustained engine speed above 2k. Most of the time it sits between 1200 and 1900 depending on road speed. 45k miles without once seeing the DPF light. 

Have you ever had a passive regen' during your 45k? MrTrilby. 

Edited 21 September, 20196 yr by Gmac983

If the passive regen means when it idles at 1kRPM, it uses more fuel than normal, and the fans run after switch off if it hasn’t finished then yes, frequently. Maybe as frequent as once or twice per fill of the tank. 

The point I'm making here is, why wait for the dpf (or gpf) light to come on in the first place. Then having to to do an "emergency" regen' which may not actually clear the filter and require specialist attention. Surely it might be better to be proactive about it, if we knew for certain when a passive regen' was occurring we could aid the process by driving as a per the handbook recommendations. Yes the latest dpf's are way better at what they do than old. But if they were 100% trouble free/reliable there wouldn't even be a warning light or prescribed driving method to correct it. 

20 minutes ago, MrTrilby said:

If the passive regen means when it idles at 1kRPM, it uses more fuel than normal, and the fans run after switch off if it hasn’t finished then yes, frequently. Maybe as frequent as once or twice per fill of the tank. 

 

Yes that's it. 

That goes to the very heart of the point I'm making here. If you were aware of this whilst driving your routine journeys you could drive as per the handbook method which would aid the regen' process, or indeed continue driving normally for a few moments to allow the passive regen' to its job and finish its cycle. Too many incomplete regens' and you run the risk of the overall dpf warning coming on. 

Do you see my point? 

Edited 21 September, 20196 yr by Gmac983