[remlemasi]

I figured it would be good to consolidate data on soot accumulation rates for those of us with DPF intact. I'm hoping this will give us some data on how different fuels produce soot. This idea came to me after using Propel HPR exclusively for almost 10k miles and then cornering myself into using Shell for one tank (poor range planning). I noticed that the accumulation rate was significantly faster than what I became used to.

I'll be updating this post every once in a while with new data. Please go ahead and post your data as well and update the same post with new data periodically (better than a new post for each entry). Discussion is fine as well.

Format:
Date
Diesel brand / type
X grams in Y miles (Z km)
Highway, mixed, or city driving (please just pick for these three options).

Here goes (rounding is approximate):

Sometime ago...
Shell ULSD
20g in 200mi (325km)
Mixed driving

2016-06-06
Propel HPR
20g in 375mi (630km)
Highway driving

[Yozh]

You may have too many variables there. People have different driving habits and also if anyone have any faults that may affect AFR (e.g.: boost leaks), you will be having different results.

[remlemasi]

Originally Posted by Yozh

You may have too many variables there. People have different driving habits and also if anyone have any faults that may affect AFR (e.g.: boost leaks), you will be having different results.

That's fair, but with enough data points for a single car, this could still help in comparing fuel types (i.e. HPR vs ULSD vs bio). Could also help diagnose or identify issues if someone's car is way off from the "norm", whatever that is.

I plan to update every once in a while and all are free to update as frequently or infrequently as desired. This is more of an open log for my own sake than anything

So far, it's looking like HPR does indeed produce significantly less soot than ULSD, as expected per HPR data sheets, but I only have two data points + fallible memory to go off of.

[BB_cuda]

How in the world are you getting grams of soot measured?

[remlemasi]

Originally Posted by BB_cuda

How in the world are you getting grams of soot measured?

Carly

[Nadir Point]

Originally Posted by remlemasi

I figured it would be good to consolidate data on soot accumulation rates...

Soot "accumulation" should be negligible on a good-running engine with complete regens taking place as scheduled.

Soot "produced" is what Carly is estimating - not "accumulated."

[QUIKDZL]

You're not seeing the big picture, Uber. A better term would be "soot collection." All diesel exhaust has soot in it, even when you don't see it. The DPF is a finer filter than the air intake filter, and it still doesn't collect all the soot produced by combustion. And Carly is not estimating anything...she is simply reporting a parameter that BMW generates and uses in its software to help determine when to regenerate, throw plausibility codes, etc.

The cycle goes like this: Car burns diesel as efficiently as it can to move you as you like, and the DPF collects as much soot as it can. At some point in time, the DPF reaches its capacity as measured by a pressure differential threshold. When this condition (and a few others) is met, the car initiates a regen cycle wherein the soot in the DPF is incinerated, and the car tells itself that the soot is now close to zero. The DPF does actually accumulate the ash that is left over from incinerating the soot, and this ash takes up space in the DPF. Over time, this accumulation adds to the pressure differential designed for use by soot, and it also reduces the available capacity for collecting soot. This is why, at some point, the DPF must be cleaned or replaced.

OP is reporting 393 miles (converted from meters) since his last regen, and Carly is showing that it is in regen at the time of this screenshot. My car usually reports 300-400 miles between regens (I usually watch the fuel consumed since last regen--it's usually around 10 gallons), but they are coming more frequently now that I had my car tuned. I'm burning more fuel (and doing it more quickly), so I am making more soot than before my tune (air:fuel ratio is richer, so more power is being made).

[Persian Whisperjet]

This may have been fixed but for some reason Carly used to mis-report the "distance since last regen" parameter. It woudl be off by like 100 km. Weird.

[Nadir Point]

That's a good detailed breakdown of what's going on with the soot, quikdzl.

Originally Posted by QUIKDZL

And Carly is not estimating anything...she is simply reporting a parameter that BMW generates and uses in its software to help determine when to regenerate, throw plausibility codes, etc.

...which turns out to be a computed "estimate," based on all the input points, as you described. The end result is "negligible" accumulation, as I stated. This negligible amout including ash eventually returns enough backpressure to require DPF maintenance. What picture am I not seeing?

[QUIKDZL]

I thought you were saying that a good-running engine would produce negligible amounts of soot, which is not the case. Perhaps I misunderstood.

My car reports less than 1 mg of soot after a regen, and then steadily collects it up to about 20 mg. This morning, Carly showed this accumulation, and then burnoff, from burning about 11.5 gallons of fuel.

[Adieu]

this collected via obd cable/bluetooth?

could smbd link to a good tried and true full featured one thats reasonably priced?

[QUIKDZL]

I use Carly for iPhone. It's an OBD wireless gongle via Bluetooth. You can even force a regen.

[QUIKDZL]

Originally Posted by Persian Whisperjet

This may have been fixed but for some reason Carly used to mis-report the "distance since last regen" parameter. It woudl be off by like 100 km. Weird.

I wonder if that could be because of confusion between the start of the regen and the completion of it?