1.6HDi DV6 Engine - DPF questions

[Welly]

Our Citroen is currently on 68K miles, something in the owners manual says about 'topping up' the eoloys fluid at 72 or 75K miles, that's fine I can understand that and the ECU being reset or whatever to suit.

BUT - what about the DPF itself? does any maintenance need doing to these units?

(sorry I should know this what with owning such a car)

Our usage would probably prevent the chief engineer at PSA's engine department from sleeping at night; mostly door to door use, only ever filled up with £20.00/£30.00 of Supermarket diesel but despite this not a peep out of the DPF system yet it does get 6-monthly oil changes with top quality oil if that's helped.

[rwb]

Every time you remove the fuel cap the fuel tank is dosed with a fixed amount of additive.
The computer calculates the amount of additive remaining (there is no level sensor) and when it's run out you get a warning message.

The additive builds up in the particle filter where it acts as a catalyst to reduce the temperature at which the soot can be burned to 'only' 400 degrees.

The computer calculates the amount of sood accumulated in the particle filter, and when it reaches a certain threshold triggers a regen. The threshold is 65% on my 2.2 HDi 407. It was 70% on the 2.0 HDi 140 508.

During a regen the exhaust temperature must be raised to over 400 degrees.
This does not happen during normal operation; it is not true that the soot naturally burns off during motorway driving.

To increase the exhaust temperature the car chanages the injection timing and places additional load on the engine by activating the glow plugs and the heated rear screen.

When the heated rear screen is on so are the heated mirrors. If you put an LED across the mirror heating terminals then you effectively create a warning lamp for when a regen is in progress.

The regen does not burn off the additive that is in the filter, therefore over time the filter becomes blocked with additive. This is also calculated by the computer.

The differential pressure sensor across the particle filter is there to detect puncture rather than blockage, and acts only as an emergency override to the computer's calculations.

You can measure in PP2k the amount of additive remaining and the amount of additive in the particle filter. Becuase I run the tank empty then fill it full I am using the least possible amount of additive.

[trem1]

What he said

[Welly]

Thanks for the info rwb, so at what stage would the DPF be 'full' of additive? at much higher mileage? and at that point is it removed/cleaned or replaced?

If I'm thinking correctly then 'stage 1' is to refill the additive pouch and carry on driving, then 'stage 2' is to replace/clean the DPF itself?

Obvs with our* repeated fill ups the concentration of additive is going to be higher

[Doggy]

In the 'old days' before dpf removal became possible the coupe boys, (who had the majority of 2.2 HDi's with dpf), removed them / pressure washed the crap out & refitted. No gaskets or anything needed so long as the connectors could be reused. No legal or ethical reason why a helpful exhaust specialist can't do this for you.

Since I can't get the cistern through the MOT without the dpf, I'll be aiming to do this if/when necessary. I read somewhere that a PSA service exchange unit is a cleaned out 2nd hand one anyway. Maybe nonsense, but its possible.

The fluid will need to refilled at some point and the counters reset via diagbox/lexia/pp2k.

Could be a nice little earner that for someone prepared to specialise.........

I've seen adverts offering illegal for road use temporary dpf removal / refit for MOT solutions aimed at (typically) the eco-conscious VAG crew for somewhere north of a grand plus ongoing swap-over costs. Not going there.

[Welly]

I see, what would you surmise would be the mileage when the 'de-crap' clean out is required?

Why can't dizzlers just have a filter cartridge that the owner can remove and put in the bin? kinda like a hoover bag?

*contacts UK Patent office*

[Doggy]

Mileage is anyone's guess, depends on how it's used. Chances are you'll get some warning in the form of error messages and/or warning light.
As the dpf blocks it will get harder and harder to start.

[trem1]

On the 407, the dpf tank holds 5 litres and gives a low fluid warning when theres 2 litres left ( refilled mine and it only took 3 litres) youngest son has run his 407 for last 5k with message showing and no issues, cars was still doing its regens as and when it should.Now refilled and counters reset etc.
Lots of people spend a lot of time worrying about this system but in reality on 407's at least it hasnt caused many headaches, over on another peugeot forum that covers all models its a similar story, so would assume citroen will be the same. Dpf's apparently to eventually block but my son-in-law has a 407 that had 240k before it was removed...........Yep it still goes though MOT as well

[Welly]

So it's not really much to worry about, will file this under: forget about it for now

Interesting about how the system changes the injection timing, I've noticed it do this as the engine starts getting a bit jerky and and sounds DEAD ROUGH...also when you stop the Rad Fan will be running.