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DPF Cleaning


HappyIdiotTalk

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I dont do much of a commute in my diesel Yeti, so the sales guy told me that I should take it out on the motorway and drive up to the next junction and back once a month to ensure the soot gets burnt off.  I've done this a couple of times, but I'm unsure of what exactly I should be doing.  Do I need to get up to say 70 in 4th gear to get the revs up, or can I just do it in 6th gear?  

 

Also, how do I determine when to take it in for an oil change or service?  Its was 3 years old when I bought it at 60,000 miles in October.

 

TIA,

 

Colin

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+3000 RPM?  Other than accelerating my Yeti doesn't hit that for any sustained amount of time. Mine will happily start a regen at/over 2000 RPM in sixth, from 60mph.

 

There was a Skoda leaflet on looking after the DPF, and I recall that saying 10 minutes of 2000-2500 over 40 mph was sufficient. So far I've not had the DPF light on, with 32K miles covered. 

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Unfortunatley for the OP the salesman is talking rubbish. Page 57 on deals with the dpf operation. giving it a quick blast up the motorway is pointless IMO. The dpf will look after itself unless most of your journeys are short unban trips, then you need a petrol instead!

 

http://www.natef.org/NATEF/media/NATEFMedia/VW%20Files/2-0-TDI-SSP.pdf

 

Signs it's doing an active regen are an increase in tickover to around 1000 rpm plus if you interupt it during the cycle when you switch off the ignition both fans will be going flat out until it's cooled the dpf down. You won't get any lights until the customer initiated regen on page 64.

 

There's loads of other threads on regens so try the search function if you want to know more :thumbup:

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Signs it's doing an active regen are an increase in tickover to around 1000 rpm plus if you interupt it during the cycle when you switch off the ignition both fans will be going flat out until it's cooled the dpf down. You won't get any lights until the customer initiated regen on page 64.

 

There's loads of other threads on regens so try the search function if you want to know more :thumbup:

+ a hot smell.

 

Fred

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This is what it says in my handbook, ....... If the warning light comes on, this means that soot has accumulated in the DPF filter because of the frequent short distances.

 

In oreder to clean the DPF, the vehicle should be driven at an even speed of at least 60Km/h ( 37mph ) at engine speeds of 1800 to 2500rpm for at least 15 minutes, or until the warning light goes out, with 4th or 5th gear engaged ( auto box position S ) when the traffic situation permits it.This will increase the exhaust gas temperature and the soot deposited in the dpf will be burnt off.

 

So the salesman is correct, as it is very difficult to acheive the above on ordinary roads. ( Unless you have a quiet dual carrigeway near you )

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This is what it says in my handbook, ....... If the warning light comes on, this means that soot has accumulated in the DPF filter because of the frequent short distances.

In oreder to clean the DPF, the vehicle should be driven at an even speed of at least 60Km/h ( 37mph ) at engine speeds of 1800 to 2500rpm for at least 15 minutes, or until the warning light goes out, with 4th or 5th gear engaged ( auto box position S ) when the traffic situation permits it.This will increase the exhaust gas temperature and the soot deposited in the dpf will be burnt off.

So the salesman is correct, as it is very difficult to acheive the above on ordinary roads. ( Unless you have a quiet dual carrigeway near you )

No he isn't. The salesman is inferring a trip up the motorway will be a good idea when no regen is taking place and that it will burn off soot already accumalated in the dpf. The situation you refer to above is for when you get a light on the dash and a driver assisted regen is taking place which is totally different- it's the 3rd of 4 stages and requires the driver to adopt a certain style to prevent the car going into limp mode requiring a forced regen at the dealer and most cr owners will never experience any lights on the dash. I think you will also find the above proceedure actually refers to the pd engine and not the later cr the OP has -the dpf leaflet I have from my dealer for the cr engine states when the light comes on you should drive at least 23 mph for 10-15 minutes with the engine above 700rpm. Driving it up the motorway for a few miles will make little or no difference IMO with the dpf in the passive state. The ecu monitors the style and type of driving you do and will initiate an active regen- increased tickover, hot smell etc as above when either the soot reaches a certain level or you have covered approx 600 miles since the last regen which ever comes first. As long as it completes this stage you'll have no problems, the next stage when you repeatedly fail to complete an active regen is the driver initiated one I.e. you get the light on the dash Very oftem my vRS will complete an active regen without me knowing it ( as I've covered far more than the 600 miles since the last one I noticed) so the op will probably best off just driving his yeti as normal and see what happens, looking out for the signs when it's doing an active regen so he can allow it to complete it - the tell tell sign that the active regen has finished is that tick over returns to normal.

 

here's the leaflet I have. You'll probably find that what is written in your manual is out of date.

Crregen_zpsd914a854.jpg

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I've looked for you but there is no publication date on it Graham. I've also looked in my owners manual and it says exactly the same as Anzio's above, but I was given the leaflet after I'd had my Blackline for some time- IIRC it was just over 12 months ago when it was in for its 1st service and was told it was the latest information for dpfs on CR engines. There was both the above leaflet and one for the PD on Skodas website but they have now gone and it just says to contact your dealer. Mines done 12k now, so based on the technical document I posted in my original post that'll it will do an active one at least every 600 odd miles my BL has done something like 20 active regens. During that time I can count on 1 hand the times I've noticed it doing one via the increased tickover/hot smell/fans and I've never had the dpf light come on to instigate a driver assist one so I would suggest you don't need to do anything special in order for the dpf to be able to successfully complete its cycle otherwise I'd have had a light on by now. Much is made about dpfs and how much trouble they are but in reality there's not much to get excited about with the CR engine providing you don't spend all your time doing short urban journeys. Cheers Ade

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There are two points to note here...

 

1) Passive regeneration.

 

2) Active regeneration.

 

Passive regeneration is where the DPF burns off the soot naturally with no intervention required. Those that spend a little more time in their cars and cover more mileage will benefit from this as the exhaust system gets hotter for longer.

 

Those that make regular but short journey's at generally lower speeds will not benefit from passive regeneration as much. This means the car will attempt to intervene with an active regeneration when it can (the parameters needed to be met are largely covered above). Here the car takes active measures by injecting more fuel and increasing the RPM in an effort to generate the additional heat required to burn off the soot.

 

So the salesman is correct, he isn't suggesting that by taking the car up the motorway will automatically start an active regen, I imagine that he meant that the DPF will remove the excess soot simply by being driven at higher speeds / RPM (therefore running hotter) through passive regeneration.

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There are two points to note here...

 

1) Passive regeneration.

 

2) Active regeneration.

 

Passive regeneration is where the DPF burns off the soot naturally with no intervention required. Those that spend a little more time in their cars and cover more mileage will benefit from this as the exhaust system gets hotter for longer.

 

Those that make regular but short journey's at generally lower speeds will not benefit from passive regeneration as much. This means the car will attempt to intervene with an active regeneration when it can (the parameters needed to be met are largely covered above). Here the car takes active measures by injecting more fuel and increasing the RPM in an effort to generate the additional heat required to burn off the soot.

 

So the salesman is correct, he isn't suggesting that by taking the car up the motorway will automatically start an active regen, I imagine that he meant that the DPF will remove the excess soot simply by being driven at higher speeds / RPM (therefore running hotter) through passive regeneration.

I agree with most of what you say Silver, but still question if the salesman was correct as you suggest as to date I have not seen any data that confirms that whilst in the passive stage the dpf is capable of burning off more soot than is being generated by the engine at that time and even if it can then he may have to do a significant number of miles on the motorway to burn off enough of the soot already accumalated during his short commuter trips to make a significant difference. As per my original thread personally I would just drive it as normal and see what happens to see if the dpf is coping with his journey profile or not. After all the dpf will do a distance based active regen what ever happens so to me there seems little point in making journeys specifically intending to try and burn soot off the next active regen will do anyway-or am I missing something?

If he keeps getting driver assist regens when the yellow dpf light comes on then it might be worth a go. Personally I'd like to hear how the OP gets on

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The distance regen is an active regen so the parameters first need to be met.

 

If the OP's daily commute / driving style is as suggested then I expect his car will struggle to complete an active regeneration, especially at this time of year.

 

A regular motorway cruise (weekly as the salesman suggested) might help as the passive regen should hopefully clear enough soot to keep the DPF light off. I think we was just covering his back. Most (decent) salesmen will now check your driving styles before selling you a diesel.

 

As has been mentioned a few times though, the best thing to do with a DPF fitted to a modern CR engine is to ignore it and just drive.

 

In most case ignorance is bliss.

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Sorry, but my Yeti is  a 140 CR 4x4. As someone else has posted, the salesman is correct.

No he isn't. The salesman is inferring a trip up the motorway will be a good idea when no regen is taking place and that it will burn off soot already accumalated in the dpf. The situation you refer to above is for when you get a light on the dash and a driver assisted regen is taking place which is totally different- it's the 3rd of 4 stages and requires the driver to adopt a certain style to prevent the car going into limp mode requiring a forced regen at the dealer and most cr owners will never experience any lights on the dash. I think you will also find the above proceedure actually refers to the pd engine and not the later cr the OP has -the dpf leaflet I have from my dealer for the cr engine states when the light comes on you should drive at least 23 mph for 10-15 minutes with the engine above 700rpm. Driving it up the motorway for a few miles will make little or no difference IMO with the dpf in the passive state. The ecu monitors the style and type of driving you do and will initiate an active regen- increased tickover, hot smell etc as above when either the soot reaches a certain level or you have covered approx 600 miles since the last regen which ever comes first. As long as it completes this stage you'll have no problems, the next stage when you repeatedly fail to complete an active regen is the driver initiated one I.e. you get the light on the dash Very oftem my vRS will complete an active regen without me knowing it ( as I've covered far more than the 600 miles since the last one I noticed) so the op will probably best off just driving his yeti as normal and see what happens, looking out for the signs when it's doing an active regen so he can allow it to complete it - the tell tell sign that the active regen has finished is that tick over returns to normal.

 

here's the leaflet I have. You'll probably find that what is written in your manual is out of date.

Crregen_zpsd914a854.jpg

 

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Sometimes I wish I knew nothing about DPF's.

 

It's only a niggle but the wife has one on her 2008 PD140 Octavia Scout. With a 10 mile daily round trip it's a worry I could do without.

 

Despite the salesman's advice you won't catch me taking it up the motorway and back every weekend :D

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Time to change the subject!

As far as servicing is concerned your car will either be on variable or fixed serice. If it's been main dealer serviced they will have a record of what services its had- do youhave anything?

At 60000 over 3 years it's likely to be on variable at the moment and the ecu decides when it needs servicing via sensors based on your driving routine but this is intended for high milage users with a max of either 2 years or 20k miles. You need to find out when it was last serviced and which service it had. Based on your comments you would probably be better off on the fixed service regime for lower annual milage/shorter journeys. This needs to be done either every 10k miles or 12 months which ever comes 1st. If you have maxidot you should be able to find out when your next service is due by scrolling through and finding the service option.

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I've logged typical EGTs (exhaust gas temperatures) on my CR170 before now, and even on long stretches of fast A-road & dual carriageway, cruising at say 60-70mph, the EGTs don't reach the temperature band that's supposedly required to passively regenerate. It takes some fairly enthusiastic driving to get to those temps. I think I posted some details in another thread a while back.

 

It came as quite a surprise, as I'd assumed that my 40+ mile each way daily commute - of which a large proportion is fast A-roads - would be perfect for passive regeneration. But my exhaust temps rarely get high enough.

 

However, the active regenerations seem to work just fine and are very unobtrusive, for me they occur every 200-250 miles or so, although it's so subtle I doubt many people would ever notice them happening.

 

They don't seem to need the car to be driven at particularly fast speeds either.

 

To promote a regeneration, you will need to meet the following criteria.

 

- +65 MPH

 

- +3000 RPM

 

- More than half at tank of fuel

 

 

Hope this helps, Regards Matt @ 

 

I don't think this is true at all for the CR engines in the Yeti. Can't help but think someone is just posting to trying and promote their website.

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Why more than half a tank of fuel?  ......and don't say in case you run out  :|

 it's to deter chavs from buying a diesel Yeti as they only ever put a tenners worth of fuel in ;)

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Now there's a thought. Wouldn't it be good if we got an indicator on the MFD telling us a regen was due in x miles time like you get for a service with a countdown etc. You could then have a start option via the scroll wheels so you could fit it in with your journeys. There, solved the problem of DPFs forever.....

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