3.0L Duramax DPF regen graphs

[wwillson]

Soot can also be oxidized by NOx. Oxidation of soot from NOx occurs at much lower temperatures , if I remember correctly it’s about 300-350C, than thermal oxidation of soot. I don’t exactly know how the SCRoF used on this engine affects passive regeneration using NOx, but it should still be happening some, unlike when the DPF is behind the SCR. Then regeneration relies entirely on thermal oxidation of the soot.

I believe you can see this by the DPF % loaded. If you climb a long grade, the % loading will decrease slightly, presumable because the delta P has decreased as some soot was burned.

 

[OneLonelyBurrito]

I believe you can see this by the DPF % loaded. If you climb a long grade, the % loading will decrease slightly, presumable because the delta P has decreased as some soot was burned.

That makes sense, the long grade is going to increase both NOx and the exhaust temperature reaching the filter allowing it to oxidize the soot out of the filter.

 

[tnt_motorsports]

Yes, 77 MPH the entire time.


No change in boost pressure other than going up and down grades, that's what the power changes were.


There is a field on the iDash, but unfortunately there is no data. It does make sense that more DEF (Diesel Exhaust Fluid) would be used during the regen, as there is more fuel burned and there would be more NOx. Some people erroneously believe that DEF is used to burn the soot out of the DPF, this is untrue. Fuel is used to heat the DPF which burns built up soot and DEF is used to react with NOx and a catalyst in the SCR to reduce NOx.

Agreed @wwillson DEF by nature is not flammable since it is Urea and water. DEF is used in a chemical reaction to lower NOx. On the 2012 Cummins, diesel fuel is injected post combustion cycle to increase the temp in the DPF to help burn off soot. I'm guessing the same on yours...

BTW, cool data.

Just my $0.02

 

[wwillson]

On the 2012 Cummins, diesel fuel is injected post combustion cycle to increase the temp in the DPF to help burn off soot. I'm guessing the same on yours...

The L5P has a 9th injector in front of the DPF.

 

[panthermike]

Any feel from the forums how long the DPF lasts? Dependent on useage?

I've seen several folks on the interwebs say around 1200 miles/gallon.

 

[wwillson]

I've seen several folks on the interwebs say around 1200 miles/gallon.

The last time I filled the DEF tank on the Tahoe, I got 1,547 MPG