Diesel Particulate Filter DPF

[Sanzomat]

So is this 2500rpm a magic figure then? I do 25 to 30k miles a year, mostly on the motorway, so I thought I wouldn't suffer any DPF issues. At motorway cruising speed I'm only doing about 2250 rpm though - does this mean it won't clear the DPF at this speed? I have noticed a couple of times that the average consumption has appeared to start dropping whilst cruising and changing to instant I see it is only doing about 35mpg instead of the more normal 45 at that steady speed so I've assumed that this is due to it going into a regeneration for a few miles. It would be good if it lit a light to tell you it was doing a regen so you would know but I imagine this would cause too much concern for people who didn't understand what a regen is...

[khoojohn]

No you got me wrong. What I meant was that if you do mainly town driving, the engine doesn't get hot enough to burn the particulates. So it's not the mileage you do but within that mileage do you have long stretches of driving where you can give the car the opportunity to burn away the soot. If not, then just rev the engine a bit moreto get the engine a bit "hotter". You will notice a burning smell or feel the car is hot when the cleaning comes on.

[br1anuk]

Just an update to this dpf thread, four days ago the dreaded "soot filter full" came up. Before i had a chance to give it a run up the motorway my wife went on a two mile journey and parked the car up.

The next morning we had the "the car must go to dealer for service" and no power from the engine.

This is the first time in ages that it's done this, but what's more annoying is the week before we drove up to Newcastle from Liverpool on a 300 mile round trip, why on earth didn't it regenerate then????

What will happen to these cars once there out of warranty and dealer service?

Brian

[orbiter]

Originally Posted by br1anuk

I was talking to a Volkswagen salesman today about replacing our V70.

I was giving him the old "it will only do 25mpg around town" and the DPF warning lights coming on every 2 weeks bit when he told me that his new boss in the sales department used to work for Volvo...........ABRIDGED

Something to think about if your about to order any new car with a DPF fitted.

Brian.

I previously had a 2007 Nissan X-Trail and after concluding the DPF was a major problem unless you do mostly Motorways, (I live in rural Devon) I decided to change cars after 8 months due to the DPF hassle. I still wanted a diesel for the torque and potential economy so went for a 2005 pre-DPF, S60 D5. A good move in many ways!

I understand however that all modern diesels do not use a standard DPF and some manufacturers, possibly some Fords, do not remove particulates by burning off the filter deposits, but instead an additive is automatically squirted into the exhaust over a period of time to remove deposits. This additive has to be topped up as a service item. I presume this complies with the latest Euro regs.

Meanwhile, perhaps older euro 3 dieselsare cars that will become more desirable because they are more economical all things considered?

Probably just wishful thinking!

[7050man]

Originally Posted by orbiter

I understand however that all modern diesels do not use a standard DPF and some manufacturers, possibly some Fords, do not remove particulates by burning off the filter deposits, but instead an additive is automatically squirted into the exhaust over a period of time to remove deposits. This additive has to be topped up as a service item. I presume this complies with the latest Euro regs.

Meanwhile, perhaps older euro 3 dieselsare cars that will become more desirable because they are more economical all things considered?

Probably just wishful thinking!

The additive is held in a separate tank on my V50 just over the axle. When a minimum qty of fuel is put into tank, a measured amount of additive is added to the fuel.

My understanding of this is that it increases exhaust gas temperatures to aid regeneration. My car is a 55 plate 2.0d E4, but as already stated, E3 engines didn't have a DPF and associated control.

There is a pressure differential sensor that measure across the DPF and when the DPF is sensed as being different at input to output, the ecu triggers regeneration.

Under this condition, half the amount of fuel or throttle, is used to make the engine run hotter.

However, newer engines 2.0D may not have a type of DPF filter that requires additive as I believe that there are two types of design for a DPF.

This is the same as the D5 and 2.4D engines where hotter exhaust temperatures negate the need to artificially increase the temp with additive in the fuel.

The type of system employed on my car is the same as the 1.6D so at 75k miles the complete DPF is replaced as a service item.

Interestingly VW and BMW must use a different type of DPF as their cars do not replace the DPF as Volvo do on their smaller engines. Keen observers will note that all VWs emit smoke, some BMW's do but to a lesser degree and all Volvo 2.0 E4 with additive system are smoke free with clean tailpipes.

Incidently, the ford Focus, that uses the same engine in the 2.0ltr, can be ordered with or without DPF.


My car has done 109k miles now and been fully serviced by Volvo. I've never had any issues with the dpf itself, but the pressure differential sensor has been replaced twice as it has caused ecu to trigger limp home mode.

I also believe that it probably affects fuel economy, partly because ecu may be given wrong signals from time to time, but also because the engine wil not breath as well as one with a free flowing exhaust.

To all of you owners that only do a small mileage, my advice would be to take the car down the motorway once in a while. It's good for the exhaust system as a whole, not just the DPF.

[orbiter]

It just seems ridiculous that as most 4x4s are diesel and in theory designed for cross country work that a driver may have to drive at sustained highish revs for 20 minutes without interuption to turn the DPF warning off.
Not very practical if you are negotiating a mountain. Not very practical if you are driving around Chelsea either.

[fenton_jd]

Originally Posted by orbiter

It just seems ridiculous that as most 4x4s are diesel and in theory designed for cross country work that a driver may have to drive at sustained highish revs for 20 minutes without interuption to turn the DPF warning off.
Not very practical if you are negotiating a mountain. Not very practical if you are driving around Chelsea either.

People are FORGETTING that petrol is fast catching up again! DPF issues are the interim whilst this new wave of petrol engines fully kicks in.

Here's an example:

59 plate VW Golf 1.4 TSI
Supercharging AND Turbocharging on the same engine
240 Nm
157bhp
0-60 7.7s
44MPG

[kev ryder]

i have now been running both petrol and diesel vehicles for 43 years in the building trade and private and cannot understand your point.

[ITServe]

59 plate VW Golf 1.4 TSI
Supercharging AND Turbocharging on the same engine
240 Nm
157bhp
0-60 7.7s
44MPG

BMW 320d M Sport Edition
Turbo Charged
450Nm Torque
222 BHP
0-60 7.2s
154mph Top Speed
54 MPG

!!

[fenton_jd]

Originally Posted by ITServe

59 plate VW Golf 1.4 TSI
Supercharging AND Turbocharging on the same engine
240 Nm
157bhp
0-60 7.7s
44MPG

BMW 320d M Sport Edition
Turbo Charged
450Nm Torque
222 BHP
0-60 7.2s
154mph Top Speed
54 MPG

!!

That is not the point. People will go out and buy a 320d and drive it to and from the shops because they were told its an economical car.

EGR valve then gums up, issues with DPF and the engine is never fully allowed to warm up.

The point I'm making is that PETROL engines do not suffer these issues, and in the last 3 years manufacturers are downsizing to small displacement turbocharged petrol engines. Good spread of torque, small turbocharger for little to no lag and very good MPG, with NO EGR/DPF/Short journey issues.

The MPG vs Performance I get from my 2.0d S40 is worse than above example of the petrol golf.

Also throw into the mix... Diesels are incredibly boring to drive. Where is the fun in an engine which cannot rev?