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-   -   DEF consumption or MPG of DEF? (https://www.irv2.com/forums/f258/def-consumption-or-mpg-of-def-280872.html)

erstanfo 02-28-2016 02:02 PM

DEF consumption or MPG of DEF?
 
I've been averaging about 270 miles per gallon of DEF.
This is about 3.2%

Diesel fuel is averaging 8.4 miles per gallon.

Just wondering if others are tracking there DEF consumption and what there is?
I've got a 2012 Winnebago 36M ISB engine pulling a jeep wrangler unlimited.
Thanks,

MRUSA14 02-28-2016 02:07 PM

My DEF use runs about 2% of fuel use.

asuperheat 02-28-2016 06:51 PM

With fresh DEF usage is 2%. as DEF ages that % goes up.

Plumnitzer 03-09-2016 01:08 PM

DEF
 
I have not done the measurements, but i was told by a service tech, DEF usage is also temperature dependent. For example, you will use more DEF in the fall and winter than you will in the summer.

mvpmich 03-09-2016 06:09 PM

Mine is about 2.8%. Freightliner and Cummins suggested that the 13 gallon tank should last about 5000 miles. I actually realize +/-4500 miles.

grant3791 03-09-2016 06:56 PM

What is DEF?

jimcumminsw 03-09-2016 07:01 PM

Quote:

Originally Posted by grant3791 (Post 2970742)
What is DEF?

Diesel Exhaust Fluid: Use in the latest Tier IV Bin 5 emission standards. This fluid is injected into the exhaust system to help clean the Diesel Practical Filter. Also known as UREA.

Slolane 03-09-2016 09:25 PM

I've been adding a 2 1/2 gallon bottle every 2-3 fill ups (average ~60 gallons)

I know this isn't real precise, but the use of DEF is DEFininately less than I expected.

G Schulz 03-09-2016 11:00 PM

Quote:

Originally Posted by jimcumminsw (Post 2970754)
Diesel Exhaust Fluid: Use in the latest Tier IV Bin 5 emission standards. This fluid is injected into the exhaust system to help clean the Diesel Practical Filter. Also known as UREA.


I think the proper term is Diesel Particulate Filter. Maybe a spell check issue.


2009 Safari Cheetah 40'
350 HP Cat
2014 Ford Focus
Air Force One

Mr_D 03-09-2016 11:10 PM

Quote:

Originally Posted by G Schulz (Post 2971076)
I think the proper term is Diesel Particulate Filter. Maybe a spell check issue.

And a new DPF is about $3,300 plus labor on our rig. Wish we had the DEF injection that the newer ones have. I think it would be more reliable than just the DPF.

jharrell 03-09-2016 11:18 PM

Quote:

Originally Posted by G Schulz (Post 2971076)
I think the proper term is Diesel Particulate Filter. Maybe a spell check issue.

Not only that but DEF does not clean the DPF, they serve two different purposes for two different pollutants.

DPF's trap soot and clean themselves through regeneration using more fuel to burn up the soot.

DEF turns NOx back into harmless Nitrogen and Oxygen.

G Schulz 03-10-2016 12:53 AM

Quote:

Originally Posted by jharrell (Post 2971087)
Not only that but DEF does not clean the DPF, they serve two different purposes for two different pollutants.

DPF's trap soot and clean themselves through regeneration using more fuel to burn up the soot.

DEF turns NOx back into harmless Nitrogen and Oxygen.


My engine has a DPF and does use diesel to regenerate it's self. Didn't think DEF used the same system but wasn't sure.


2009 Safari Cheetah 40'
350 HP Cat
2014 Ford Focus
Air Force One

jharrell 03-10-2016 09:23 AM

1 Attachment(s)
Quote:

Originally Posted by G Schulz (Post 2971138)
My engine has a DPF and does use diesel to regenerate it's self. Didn't think DEF used the same system but wasn't sure.

They do different things, DPF is for soot, DEF is for NOx.

They have a relationship in that for an engine to have met NOx emissions up to 2010 without DEF it needed more EGR to run cooler, because heat and pressure is what creates NOx from air. However when the engine runs cooler it creates more soot causing the DPF to need more often regeneration. So DEF helps reduce regeneration indirectly only because the EGR can now be reduced increasing temps, which also helps mileage and power. It doesn't necessarily change how regeneration is done, only how often it's needed.

For 2010 emission engine makers realized they couldn't meet the tougher standards without DEF, they tried everything, Navistar really tried and failed. EPA doesn't care how you get emissions down, just so happens DEF is the only viable way to get NOx down right now. Volkswagen got caught tweaking EGR which reduced power and mileage but only while testing instead of going with DEF, then on the road it ran hotter but no DEF, so it put out 40 times the NOx.

Here is a diagram, notice how the DEF system is after the DPF:

Attachment 121098

djbmsu 03-10-2016 08:09 PM

To reply to the original question, 0ur 2014 Phaeton avg about 425 miles per gallon of DEF


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