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Diesel Engines A forum dedicated to diesel engines fitted to Volvo cars. See the first post in this forum for a list of the diesel engines. |
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DPF problems? hmmmm......Views : 6689 Replies : 35Users Viewing This Thread : |
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Jul 18th, 2010, 20:46 | #1 |
Senior Member
Last Online: Nov 6th, 2018 10:16
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Location: stockton
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DPF problems? hmmmm......
having read some of the posts about dpf problems/smoking/upgrades, and getting the basic idea of how this system works(i dont profess to know EXACTLY what im talking about so please feel free to correct me if you know better) ive been thinking a bit (yes...thats the burning smell)...
people generally buy a diesel for fuel economy. i suspect most of these drivers, as with probably 90% of volvo drivers, are sensible, easy on the throttle,look after the car and try to obtain max mpg type people. nothing wrong there. but, having mot'd lots of diesel engined cars, some of which were in top condition, looked after and cherished by their owners, i noticed that these were the ones that always failed on emissions test. they blasted soot out the back when revved up during testing(smoke meter reading off the scale) we would take them up the road and clear the soot with some high revs/ good thrashing. emissions would be spot on after that. another year of carefull driving and we would have to do the same again come mot time.... now, maybe(i dont know) volvo could have had reports/waranty claims of dpf problems ie, failing emissions,sooting up/blocked (possibly through careful economic driving styles) and has responded to dpf choking up with soot by increasing the fuel that stokes the fire to clean the filter(right?). maybe they think there is a problem with the system, not driving styles... sooooo,still with me?, volvo upgrade the software, more fuel is being used to clean the dpf, when the dpf is cleaned of all the soot...the software is still using an increased amount of fuel, which now MIGHT not be fully burning (because there might be a bit too much of it) in the clean dpf and especially if the dpf is not at full operating temperature. this will give you plumes of white smoke(i reckon anyway). if i owned a diesel, i would regularly get it nice and hot and give it a thrash to clear the soot out, it does them good,especially when you have egr systems and stuff that help clog up intake manifolds and the like. this probly wont help AFTER this software upgrade, as you will still be getting too much fuel. all of this might already have been discussed/blown out of the water, but i just thought i would share my opinion and hopefully be of a little help to someone. feel free to correct/educate me as i say, im not an expert on dpf's :-) |
Jul 19th, 2010, 00:15 | #2 |
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First, thanks for starting another DPF thread. It is clearly one of the main issues affecting modern Volvos, and the greater the visibility, and the more threads, the better. However you say you're not an expert and if you don't mind me saying so, it shows.
Taking the car for a thrash is completely pointless, unless you do so at a time the DPF needs regenerating, which can't be predicted. In fact it would be counter-productive to do so at any other time, as 'thrashing' the car would just add to the DPF's congestion. When the DPF does need regenerating, you may not have access to a motorway to give it a 'thrash' (perhaps you're on a relaxed holiday?), or it may be winter with snow & ice that stops you driving fast, or you may be stuck in an M25 circular traffic-jam, or all manner of other things that could stop you taking the car 'for a thrash'. Quite apart from all of that, DPFs are incompatible with bio-diesel blends, which is all that can be bought in the UK nowadays. In order to understand the gravity of DPF problems, may I suggest you refer to the thread at: http://www.volvoforums.org.uk/showthread.php?t=95323 |
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Jul 19th, 2010, 08:29 | #3 |
Grumpy Old Sod
Last Online: Dec 14th, 2021 15:39
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Location: Hampshire, nee Scotland
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@bill_56, I think that you are wrong about taking the car for a thrash.
The DPF only requires to forcibily regenerate when it is getting blocked, and that happens because the car has been driven on short journeys where the exhaust system has not had sufficient time to heat up the DPF. The DPF will clear the soot from the filter at any time when it gets hot enough. Ergo, taking the car for a 'burn' up the road will prevent the need for forced regeneration. Of cource the other way to prevent this issue - which is not unique to Volvo! - is not to use a diesel engined vehicle for short journeys. |
Jul 19th, 2010, 10:54 | #4 | |
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Quote:
"The particles in the exhaust gasses are collected in the filter during normal driving. So called "regeneration" is started in order to burn away the particles and empty the filter. This requires the engine to have reached normal operating temperature." "Regeneration of the filter takes place automatically at an interval 300-900km depending on driving conditions. Regeneration normally takes between 10 and 20 minutes. During this time fuel consumption may increase" Does yours say something different? |
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Jul 19th, 2010, 12:33 | #5 |
Grumpy Old Sod
Last Online: Dec 14th, 2021 15:39
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My manual says the same, but I contend that an interval as wide and as varied as this specifies is normal motoring and as such does not constitute some specifally different action that is being undertaken. I define forced regeration as when you need to take the car on a journey which is not required as part of normal motoring to clear the DPF
The issue that people are having is not seen when the engine is driven on longer journeys where the exhaust system get hot, this is partly due to more efficient burning, partly due to the the regeneration happening, and is enhanced by having a hot exhaust system. The soot warning happens when the car is driven regularly in cold conditions for short journey and it is then that you need to thrash the engine for 20mins plus to get the exhaust hot and undertake the forced regeneration, rather than normal driving regeneration. |
Jul 19th, 2010, 12:37 | #6 |
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