See the end of this thread: http://www.myturbodiesel.com/forum/f19/dpf-delete-5966/ someone cut apart their Euro DPF. The North American DPF have a cat before the DPF but the cat is a hole-through so I believe any ash can come out through that end. It would have to be removed from the car.
Thanks Chitty. I would think that since these engines have been around for a few years now that someone would have lots of miles on one and could report back with their real-world experience. Having said that, it sounds like it's reasonable to think that by the time the majority of 2.0 TDIs hit 120k+ miles that there might be a cost-effective way to deal with this fairly significant maintenance issue.
I first looked into doing DPF cleaning and refurbishing. No company offers it due to the complexity of the downpipes and the system. If someone has a high mileage dpf I would love to get my hands on it to inspect the components to see how things fare after long periods.
Here is the crap shoot of the OEM downpipes... I have heard from sales guys with over 140k on thier 2009 TDI's without issues, but I have also had customers with 30k and a DPF failure (more people call me in this case). From what I have been seeing many of the DPF issues come into play if the following happen:
1) users drive with excessive hypermilage on the mind and never exercise the engine. (this leads to higher levels of ash quicker and does not allow the car to clean the dpf during operation)
2) If an intercooler pipe pops off and users drive the car AT ALL, you will clog your DPF
3) bad or faulty EGR parts (I have yet to determine which) are causing excessive smoking and higher ash levels decreasing DPF life
4) I have been seeing quite a few reports of cars with cooked turbos showing up on DPF cars. This may be from DPF issues or one of the above.
Overall, to help keep your dpf life make sure you have you use your car slightly agressively after warmup to keep regen cycles low. Also, if you get a check engine light, have no boost pressure, or feel a major lack of power do not drive your car and call your local dealer or mechanic to take a look at it.
Over here in Australia we have had the older style combined DPF/Cat since late 2007 on a few cars, but my direct experience is the 170hp BMN engine. Seems DPF's clog quickly due to the situations you mention above, basically down to soot production / off boost situations, where the isn't enough air for the fuel injected via the accelerator pedal. Inner city driving is the biggest killer, and it actually takes some pretty aggressive driving to get the DPF towards anything like DPF passive regen temps from my experiments.
I have heard of a few DPF's clogging terminally around 100k, but VW tell me they should last 150k. I put a Provent on my TDI from new, and have since hobbled the EGR, both of which contribute to DPF clogging. VW themselves state in their manuals that oil ash cannot be regenerated, and eventually builds up in the DPF, so oil quality, blowby quantity and overall engine condition are important factors there. Certainly running the engine in hard to bed the rings as best you can is important to reduce overall blowby.
EGR lowers combustion temps to drop NOX production, but in turn reduces available O2, adding to soot production. Certainly since hobbling my EGR, and making a lot of mods to both lower the temps and increase the flow, my DPF actively regenerates a lot less.
In my mind the DPF needs to be kept as hot as possible, and some sort of thermal wrap / coating would only be beneficial there. Someone needs to produce an electric blanket concept, where you can actively bake your DPF, and get the temps into the range where passive regen starts to happen.
An EGT gauge coupled with a boost gauge are powerful tools to learn how to drive to avoid soot, and to get the DPF temps up when it's possible and legal to do so, such as up a long hill.
I do see the new split DPF in the MK6 as a good step forward, and hopefully a reduced cost when they eventually clog, which should be a lot longer with common rail, DPF and PD were never designed to work together, common rail will definately produce less soot overall.
The car will throw a forced "active" regen at about 40% blocked, the DPF light comes up if this fails and it approaches 50%, and the coil light joins the fray at 60% blocked plus. I've tried all those steps by turning regens off to see what happened. Apparently the car goes into limp and wonlt actively run after 80% blocked, and this process would happen within 2 months of normal driving without regens in my approximation.
Just give it a blast up the freeway/motorway now and then that will keep it clean. They become more clogged the slower running you do. I do 70% local running and I just give it a blast up the motorway every couple of weeks and I've never had my DPF light come on?
This blast rule applys to gas/petrol as well not that they have DPF's but local running just collects water in the back exhaust box so is corrodes from the inside, you just need to burn that water off. For every gallon of petrol you put in the motor you get a gallon of water out of the exhaust so it needs to be burnt off/evaporated? Now we only did a bomb calorimeter test on petrol but its going to the the same for diesel?
My 09 has 77k miles and lights are on for dsp. Would love to hear of someone's experience cleaning the dsp. I drive all highway, pretty aggressive - not hyper mile'ing. I tried the VW suggestion of driving harder, and maintains 2500+ rpm for extended period. No luck.
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