X5 35d "de-particle" process

[deutsch100]

How often does this departicle process take place? It seems to happen a lot while driving (which is better than in the garage after being parked...this process stinks), but when it occurs while driving, the car is noticeably "heavy, coarse and sluggish" feeling. It does pass generally quickly, but seems to be a frequent process!

[Diesel Guy]

It's called "regeneration"...... Passive regeneration occurs normally while driving if exhaust temps are high enough.....active regeneration occurs when temps are low, and as the back pressure in the catalyst rises, the system begins to regenerate.....and this is what you might smell when you pull in the garage .......I haven't sensed any performance issues, and I don't know if BMW is able to control either turbo to raise temps during regen which might be the performance issues you've sensed....

[deutsch100]

Originally Posted by Diesel Guy

It's called "regeneration"...... Passive regeneration occurs normally while driving if exhaust temps are high enough.....active regeneration occurs when temps are low, and as the back pressure in the catalyst rises, the system begins to regenerate.....and this is what you might smell when you pull in the garage .......I haven't sensed any performance issues, and I don't know if BMW is able to control either turbo to raise temps during regen which might be the performance issues you've sensed....

Thanks for the response. The manual in my '11 35d, actually calls it departicle process, but regeneration makes sense too! It mentions that during this brief process you might need to press the accelerator more, and notice a different feeling in the car while driving. Usually this "process" happened when I pull in the garage, but lately it's been happening when I am driving.

Funny, I imagined the majority of the "smell" would come from the exhaust pipes, but when this process happens while parked in the garage...the smell is strongest in the engine bay!

[Armand]

In over 15k miles I can't say that I have definitely spotted one much less felt sluggishness or other performance impact. I am sure it is happening but it manages to go unnoticed.

[deutsch100]

Originally Posted by Armand

In over 15k miles I can't say that I have definitely spotted one much less felt sluggishness or other performance impact. I am sure it is happening but it manages to go unnoticed.

Do you do more highway driving? My driving is at least 90-95% city driving, so there are many chances to notice this. I imagine on the highway or at a steady speed...it would be totally unnoticeable.

You've never had the funny smell when pulling in the garage, or parking? I get it quite often. Even called the dealer, and they said almost EVERY diesel owner calls about this "smell". It's even in the manual!

[Armand]

Originally Posted by deutsch100

Do you do more highway driving? My driving is at least 90-95% city driving, so there are many chances to notice this. I imagine on the highway or at a steady speed...it would be totally unnoticeable.

You've never had the funny smell when pulling in the garage, or parking? I get it quite often. Even called the dealer, and they said almost EVERY diesel owner calls about this "smell". It's even in the manual!

I believe I noticed the smell once on the street. I got out of the car and immediately noticed a sweet smell. I only drive it weekends on relatively longer drives. But never noticed a loss of power or anything unusual. My wife drives the rest of the week (mostly around town) and she has never complained about the smell. I wonder if fuel could influence the frequency of regeneration. Do you get winter diesel? I think winter diesel has higher particulate content and so I would expect the engine to regenerate more frequently. Also, I don't use unbranded diesel nor additives.

Edit: I noticed you live in Woodland Hills so no chance of winter diesel! Can't think of another reason ...

[boyce89976]

We've put 2k miles on our 2010 X5d and have not noticed this process at all, either while driving or while in the garage.

[JasonG]

I've noticed mine regen once in about 1700 miles....smells sweet...didnt notice while driving but when we pulled up to the house....

[Diesel Guy]

The regen process is different for each OEM. The addition of raw diesel fuel to the exhaust stream will chemically increase the temperature of the particulate filter, and chemically remove the carbon trapped on the DPF. This process does not remove ash. Ash is a component of lubricating oil, that gets past the piston rings, and since an ash molecule is larger than carbon, it remains in the DPF until mechanically removed. This is why it is important to only use a low ash oil that is recommend by the manufcturer.

Here's a link to the Cummins site with a video that shows what's going on during an active regen event...similar to what BMW does, but not 100% the same....

The DEF fluid is only associated with NOx reduction, and takes place in a separate catalyst, after the DPF. A tailpipe sensor manages the injection of DEF to control NOx

[Aidan]

For anybody that is equipped with a DPF, should take their car out on the motorway and give it a good spiritual drive occasionally. DPFs become problematic with town and city driving.