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-   -   Diesel Particulate Filters (DPF) (http://forums.digitalspy.co.uk/showthread.php?t=1790040)

Porcupine 24-01-2013 09:31

Diesel Particulate Filters (DPF)
 
I recently bought a 2nd hand KIA (2007) and I adore it. But over the last few days I could smell a burning smell from the back of the car when sat in a queue or when i got home / work.

I then did some research online, and it turned out it was the DPF. The trouble is, like anything you research online from stomach aches (probably dying) to headaches (probably dying) I am now a little concerned.

A lot of people have said that you shouldn't even consider a new (ish) diesel car if you aren't travelling a lot. It certainly shouldn't be used as a 'run around'.

So - does anyone here who drives a diesel car worry about this, and do you just use it around town ? Has this DPF filter caused any problems ? Do you occasionally take it out on a longer run and give it a bit of welly on the dual carriageway ?

Mustabuster 24-01-2013 09:40

If you only use it for short journeys you should give the car a long trip to blow stuff out every do often. This helps catalytic converters out as well as DPFs.

I commute 15 miles each day so I don't have that problem but all cars need to be run to proper temps just to keep them healthy.

Finglonga 24-01-2013 09:45

Quote:

Originally Posted by Porcupine (Post 63818856)
Do you occasionally take it out on a longer run and give it a bit of welly on the dual carriageway ?

Better on the motorway at quiet times so you can keep the speed constant so it can do a full regeneration cycle. I come home the long way from work every so often down the M54 as it is 7miles between Jctn 2 & 3 and does the job perfectly.

If/when it does fail then it will be coming off and have it deleted from the ECU, I will not be replacing it.

grotbags1 24-01-2013 09:45

Quote:

Originally Posted by Mustabuster (Post 63818966)
If you only use it for short journeys you should give the car a long trip to blow stuff out every do often. This helps catalytic converters out as well as DPFs.

I commute 15 miles each day so I don't have that problem but all cars need to be run to proper temps just to keep them healthy.

Same here, I do 15 miles each way, most of it motorway so I've never had a problem with the DPF. I got documentation with the car telling me that it should have a decent 20 minute run each day to keep it ticketiboo as it were.

Porcupine 24-01-2013 09:55

I think because i got it 2nd hand the DPF wasn't mentioned to me. I scoured the manual last night and nothing is mentioned at all. I know the DPFs were required by law from 2009 onwards, and as mine was made in 2007 I thought it might not be on it. But reading online, a lot of manufacturers put them in early knowing it would soon be a requirement. It looks like KIA was one of these manufacturers.

I drive 8 miles to work and back every day, but there is quite a lot of stop / starting, which means the soot won't blow out. Plus, being a diesel, it takes a while for the car to warm up anyway.

diary_room 24-01-2013 10:02

Modern diesels now all have DPFs by law and you are right, you cannot use them as runabouts around town. You HAVE to take them on the motorway regularly or expect to need a costly and time consuming DPF replacement.. This is a real pain and is a reason I will not buy a modern diesel now.

This needs to be common knowledge and it's negligent for dealers not to be making this absolutely clear to customers.

flagpole 24-01-2013 10:03

Quote:

Originally Posted by Porcupine (Post 63819162)
I think because i got it 2nd hand the DPF wasn't mentioned to me. I scoured the manual last night and nothing is mentioned at all. I know the DPFs were required by law from 2009 onwards, and as mine was made in 2007 I thought it might not be on it. But reading online, a lot of manufacturers put them in early knowing it would soon be a requirement. It looks like KIA was one of these manufacturers.

I drive 8 miles to work and back every day, but there is quite a lot of stop / starting, which means the soot won't blow out. Plus, being a diesel, it takes a while for the car to warm up anyway.

stop starting is fine. it's the engine speed not the speed of the car.

i assume when you say 8 miles you mean 2x4miles? either way 4 miles, especially in traffic, is going to get the engine thoroughly hot.

David (2) 24-01-2013 10:07

do diesel engines take longer to warm up - i drive one and find the warm up period about the same as my last petrol car. I am only going by the pos of the temp needle.

Porcupine 24-01-2013 10:09

Quote:

Originally Posted by flagpole (Post 63819261)
stop starting is fine. it's the engine speed not the speed of the car.

i assume when you say 8 miles you mean 2x4miles? either way 4 miles, especially in traffic, is going to get the engine thoroughly hot.

No sorry, My fault for the way I wrote it. Its 8 miles one way, then home again. This is 5 days a week. So 16 miles a day.

I also tend to drive quite sedately to save diesel. I don't give the car much welly at all. My husband now thinks i should be a little more aggressive to blow the soot out and accelerate from junctions a little harder. He thinks the extra small amount of diesel used is worth it, as it might stop the DPF being a problem. Previously i changed gear to move into 5th / 6th as soon as possible, but we are now thinking that I should be driving in a higher gear to give it some blow.

Am I making any sense at all ?

David (2) 24-01-2013 10:09

How many miles is needed to make sure the DPF doesnt get blocked?
My current one doesnt have a DPF, but its a concern for me when i next replace the car.

Porcupine 24-01-2013 10:10

Quote:

Originally Posted by David (2) (Post 63819321)
do diesel engines take longer to warm up - i drive one and find the warm up period about the same as my last petrol car. I am only going by the pos of the temp needle.

I know mine takes longer to heat up. I was previously driving a petrolToyota Yaris would would heat up very quickly. In the KIA it takes about twice as long.

David (2) 24-01-2013 10:19

as for petrol cars warming up, i have seen some which warm up more quickly than others.

flagpole 24-01-2013 10:20

Quote:

Originally Posted by Porcupine (Post 63819341)
No sorry, My fault for the way I wrote it. Its 8 miles one way, then home again. This is 5 days a week. So 16 miles a day.

I also tend to drive quite sedately to save diesel. I don't give the car much welly at all. My husband now thinks i should be a little more aggressive to blow the soot out and accelerate from junctions a little harder. He thinks the extra small amount of diesel used is worth it, as it might stop the DPF being a problem. Previously i changed gear to move into 5th / 6th as soon as possible, but we are now thinking that I should be driving in a higher gear to give it some blow.

Am I making any sense at all ?

I follow but it doesn't make sense no.

If you are driving 8 miles twice a day every day this is plenty to get the car running at optimal temperatures.

you can't blow the soot through the filter by revving hard. it is specifically designed to capture the soot, to not let it through, if you thrash it you'll just generate more soot.

If all you used your car for was to go to the corner shop then that would be different. but you're not, your using it as intended, you don't need to do anything else.

Richard46 24-01-2013 10:27

Quote:

Originally Posted by grotbags1 (Post 63819042)
Same here, I do 15 miles each way, most of it motorway so I've never had a problem with the DPF. I got documentation with the car telling me that it should have a decent 20 minute run each day to keep it ticketiboo as it were.

Each day! I never heard that. What car is it?

My last two cars have been diesels but what with this DPF nonsense, the price of diesel and the improvements in petrol car consumption I will not be getting another one.

Porcupine 24-01-2013 10:30

This is where I got my (perhaps daft) theory from:-

When the soot loading in the filter reaches a set limit (about 45%) the ECU can make small adjustments to the fuel injection timing to increase the exhaust temperature and initiate regeneration. If the journey is a bit stop/start the regeneration may not complete and the warning light will come on to show that the filter is partially blocked.

It should be possible to start a complete regeneration and clear the warning light by driving for 10 minutes or so at speeds greater than 40mph.

If you ignore the warning light and keep driving in a relatively slow, stop/start pattern soot loading will continue to build up until around 75% when you can expect to see other dashboard warning lights come on too. At this point driving at speed alone will not be enough and you will have to take the car to a dealer for regeneration.

On cars with a very high sixth gear the engine revs may be too low to generate sufficient exhaust temperature for regeneration. Occasional harder driving in lower gears should be sufficient to burn off the soot in such cases.

http://www.theaa.com/motoring_advice...e-filters.html

gds1972 24-01-2013 10:42

Quote:

Originally Posted by flagpole (Post 63819473)
I follow but it doesn't make sense no.

If you are driving 8 miles twice a day every day this is plenty to get the car running at optimal temperatures.

you can't blow the soot through the filter by revving hard. it is specifically designed to capture the soot, to not let it through, if you thrash it you'll just generate more soot.

If all you used your car for was to go to the corner shop then that would be different. but you're not, your using it as intended, you don't need to do anything else.

With a Diesel car that only does short jouneys without going on the Motorway you need to occasionaly drive the car using slightley higher revs say using 3rd gear instead of 4th. Driving like this is about allowing the car to generate heat in the exhaust to allow the soot to be burnt off in the DPF. Sometimes if you are in traffic when the DPF regeneration is being carried out you can smell something is running very hot.

Porcupine 24-01-2013 10:46

Quote:

Originally Posted by gds1972 (Post 63819781)
Sometimes if you are in traffic when the DPF regeneration is being carried out you can smell something is running very hot.

This is when I noticed the burning smell at first, sat in a queue of traffic.

flagpole 24-01-2013 10:48

Quote:

Originally Posted by gds1972 (Post 63819781)
With a Diesel car that only does short jouneys without going on the Motorway you need to occasionaly drive the car using slightley higher revs say using 3rd gear instead of 4th. Driving like this is about allowing the car to generate heat in the exhaust to allow the soot to be burnt off in the DPF. Sometimes if you are in traffic when the DPF regeneration is being carried out you can smell something is running very hot.

for sure, but that is the process working as intended. showing you don't need to be on the motorway for it to happen.

people do rave about the importance of the motorway, but my merc is doing 1300 revs at motorway speed. in traffic it gets much hotter.

if she was only going to get a paper every day i'd agree with you. but 8miles in traffic twice a day will have it running hot.

johnny_t 24-01-2013 10:54

You might find (I did in my Peugeot 807) that it is something that will be more common at this time of year, just because everything is so much colder to begin with. You need to take it for the occasional longer spin just to clear the filter out....

flagpole 24-01-2013 10:55

Quote:

Originally Posted by Porcupine (Post 63819596)
This is where I got my (perhaps daft) theory from:-

When the soot loading in the filter reaches a set limit (about 45%) the ECU can make small adjustments to the fuel injection timing to increase the exhaust temperature and initiate regeneration. If the journey is a bit stop/start the regeneration may not complete and the warning light will come on to show that the filter is partially blocked.

It should be possible to start a complete regeneration and clear the warning light by driving for 10 minutes or so at speeds greater than 40mph.

If you ignore the warning light and keep driving in a relatively slow, stop/start pattern soot loading will continue to build up until around 75% when you can expect to see other dashboard warning lights come on too. At this point driving at speed alone will not be enough and you will have to take the car to a dealer for regeneration.

On cars with a very high sixth gear the engine revs may be too low to generate sufficient exhaust temperature for regeneration. Occasional harder driving in lower gears should be sufficient to burn off the soot in such cases.

http://www.theaa.com/motoring_advice...e-filters.html

that's all grand but pulling off the lights like a lune once or twice a day wont make any difference. that wont 'blow' the soot out. the process happens over a sustained period, not in a few seconds.

i believe that the way you are driving it should be fine. if the warning light does come on then get yourself on the motorway at 70mph in one less than top gear. but i think the way you are driving it should be fine for you to not have to think about it.

grotbags1 24-01-2013 10:58

Quote:

Originally Posted by Richard46 (Post 63819559)
Each day! I never heard that. What car is it?

My last two cars have been diesels but what with this DPF nonsense, the price of diesel and the improvements in petrol car consumption I will not be getting another one.

It's a Scirocco, I might have been making that up as I've had it 3 years so my memory of what this document said could well be rusty. I remember 20 minutes about something though :confused: sorry for being misleading.

trphil 24-01-2013 13:04

Quote:

Originally Posted by flagpole (Post 63819874)
for sure, but that is the process working as intended. showing you don't need to be on the motorway for it to happen.

people do rave about the importance of the motorway, but my merc is doing 1300 revs at motorway speed. in traffic it gets much hotter.

if she was only going to get a paper every day i'd agree with you. but 8miles in traffic twice a day will have it running hot.

I'd be a bit worried if my car ran hotter in traffic than on the motorway as it would either indicate that it's overheating in traffic or not at operating temperature on the motorway. Or do you just mean it warms up quicker in traffic?

Incidentally 8 miles won't necessarily bring a car up to operating temperature, my Ford S-Max 1.8 diesel (luckily no DPF:D) takes the first 10 miles of my 30 mile commute to warm up fully at this time of year. :eek:

gds1972 24-01-2013 13:31

Quote:

Originally Posted by trphil (Post 63821922)
I'd be a bit worried if my car ran hotter in traffic than on the motorway as it would either indicate that it's overheating in traffic or not at operating temperature on the motorway. Or do you just mean it warms up quicker in traffic?

Incidentally 8 miles won't necessarily bring a car up to operating temperature, my Ford S-Max 1.8 diesel (luckily no DPF:D) takes the first 10 miles of my 30 mile commute to warm up fully at this time of year. :eek:

Depending on the setup of the vehicle DPF regeneration heats the exhaust to a temperature of 400C-600C or higher. This level of heat may become noticable to the driver in statonery or slow moving traffic.

SnrDev 24-01-2013 14:54

Don't take it for a thrash - as someone else said, that creates soot not clears it.

The DPF clears by running at higher temperatures (by burning more fuel, so MPG drops too) for a decent distance at a reasonable speed; it's more to do with how long not how fast so although the burning smell in traffic is indicative of the DPF regeneration cycle occurring, it might not be long enough to complete it hence the need to go for a run.

Give it a steady run at road speeds for 30 minutes or more and see if that clears it up. It may be that the DPF has reached its natural end of life anyway - mine is supposed to last 75-80,000 miles, and it did. You don't have to buy a manufacturer's full price replacement; after-market DPFs are much cheaper and although they may not last as long as an OEM they don't have to, unless you plan to do another 70+000 miles. Mine was 350 instead of 980. That's the sort of difference you're looking at.

Porcupine 24-01-2013 15:20

Quote:

Originally Posted by SnrDev (Post 63823638)
The DPF clears by running at higher temperatures (by burning more fuel, so MPG drops too) for a decent distance at a reasonable speed; it's more to do with how long not how fast so although the burning smell in traffic is indicative of the DPF regeneration cycle occurring, it might not be long enough to complete it hence the need to go for a run.

Give it a steady run at road speeds for 30 minutes or more and see if that clears it up.

But my journey doesn't last 30 mins or more. Thats the problem. I haven't had a warning light come on or anything. I have read that when the light come on (if ever) you can clear it by going on a long run. We did go out last night for a good 40 mins drive, which probably did it good.

So - do you think i should still to my normal driving style, by working up the gears to 6th gear and not giving it any welly.


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