I am not an expert on DPF filters fitted to majority of diesel cars nowadays. From what i read it seems it makes you waste more fuel. This is what i have learned from different sources, don't know how accurate they are...
1. you need to take it on a fast run to clear the filters, maybe once a week. This means unwanted journey
2. need to keep the revs above 4000 rpm to clear the filters
3. DPF can go through regeneration cycle which uses extra fuel
4. one forum states that to clear the clogged filter you have to rev the car at high revs for a long period of time.
It may be great to reduce emissions but does it not make you waste more fuel?
Looking forward to being corrected
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Surely it depends on your average drive.
If it includes a reasonable period of driving on a main road or motor-way and you accelerate reasonably from time to time you will be fine. If you never get above 2000 rpm and simply tootle about town then a car with a DPF is not for you
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>>>1. you need to take it on a fast run to clear the filters, maybe once a week. This means unwanted journey
yes if the vast majority of your driving is slow short journeys but then "one" wouldn't buy a diesel for that type of use
>>>2. need to keep the revs above 4000 rpm to clear the filters
sounds a bit high for a diesel (80% to 90% of max revs?) but yes you'd need to maintain high revs for a period of time, how long depends on how clogged the dpf is - if lots, the dpf warning light will come on and you'll need to go for an unnecessary and spirited drive
>>>3. DPF can go through regeneration cycle which uses extra fuel
yes, it does burn extra fuel, how much again depends on how clogged ..
>>>4. one forum states that to clear the clogged filter you have to rev the car at high revs for a long period of time.
see 1,2 and 3
>>>It may be great to reduce emissions but does it not make you waste more fuel?
Even with the fuel wasted/used on purging the dpf the effect on economy will be minimal but still it is extra fuel and the process itself by its nature produces extra emissions .....
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You may need, depending on the make of the car, to factor in the cost of EOLYS fluid @ £25 a litre and one needs 5 litres of it for a re-fill. I have had a Pug 1.6 hdi for 6 years and it is has not yet needed any EOLYS or any work on the dpf and I get something near 60 mpg, over all. I also run a 1260cc (?) Ford KA and, driven very gently I am pushed to get 53mpg and this is driven on minor roads and within the speed limits
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Odd isn't it, at one time Diesels were the choice for economy for general use and especially stop start short journey work, and simple non turbo motors the most tractable for town driving.
Never had a problem so long as you serviced the things reasonably and changed the cambelt on time, they were as economical cold running with lots of ticking over as it was possible to get.
With DPF if your journey pattern should change you must drive for no good reason to somewhere you can give the car a constant 20+ minute thrashing to clear it out, that'll be handy for someone living in Streatham where it might take an hour to reach such a road, then by the time they've driven back through the traffic after hopeful full clear out it will be starting to clog up again, and that's economical.
I especially like the fact that it's all guesswork anyway, and should the driver's guess be wrong they are to blame, how does the driver know when all is clear.
No thanks.
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>> You may need, depending on the make of the car, to factor in the cost of EOLYS fluid
EOLYS is used by FAPs not DPFs.
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Many thanks for the polite and tactful correction! IF you need EOLYS it is expensive.
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You can remove the DPF and have the car remapped to avoid it looking for the various pressure sensors and what not on the DPF section (so it wont trigger the check engine light for a missing DPF).
Extra ~3mpg or so
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I have soved all the DPF woes, my Kia ceed 1.6 crdi does not have one.
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ON - what does it have? Does it meet the Euro IV or V rules without any gubbins in the exhaust? Is so why are other manufacturers faffing about with all their expensive and fuel consuming trickery?
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>> EURO IV
Not all diesel engines need a DPF to meet Euro IV requirements. Renault's 1.5 dCi, also used in various Nissans, doesn't have one either.
Good to know that you can remap and remove the blasted things. That is certainly something I would consider for the future.
Last edited by: DP on Thu 15 Jul 10 at 12:26
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>> ON - what does it have? Does it meet the Euro IV or V rules
>> without any gubbins in the exhaust? Is so why are other manufacturers faffing about with
>> all their expensive and fuel consuming trickery?
>>
It just has a recently designed, very efficient engine. The icing on the cake is no DMF either. Unfortunately it has an EGR but the 7 year warranty covers that.
Last edited by: Old Navy on Thu 15 Jul 10 at 13:28
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To answer the OP's question I'd contend that the DPF on my A4 170PD most certainly did increase fuel consumption, I'm not sure to what extent but I'd estimate 5% as a conservative figure as it struggled to do 40mpg.
My current 330d easily does 45+mpg (I do a lot of motorway miles), not sure what it would do without a DPF but I've never noticed it regenerate and I'm delighted by the economy, don't think I've ever got less than 40mpg even when I do a lot of urban motoring.
DPF=bung in exhaust so must have an impact on economy/CO2, better for people with asthma though?
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>> DPF=bung in exhaust so must have an impact on economy/CO2, better for people with asthma though? <<
As usual the Govt has seen the problem and grabbed it by the wrong end.
Why make every single diseasel less efficient, burning more precious resources and increasing the output of evil carbons??
Give every asthmatic miniature 'bungs' for their nostrils.
Job done - planet saved.
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My previous car, a MkIII Mondeo TDCi was Euro IV without a DPF. But for Euro V you need a DPF at the moment so they will have introduced a DPF for EuroIV to do some testing/development.
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Nothing like the punters for R and D.
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The FAP on my C5 uses more fuel when it regenerates, but I reckon thats only once every two tanks / 1500 miles, and the regen takes about 10 mins. You can see the instant fuel consumption drop by quite a bit, and the cooing fan is quite often running afterwards when I stop
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Is DPF a burden on economy of the car - CGNorwich
