Facts about DEF

mattpopp

mattpopp

Trouble Maker
Since the introduction of DEF for our pickups, Ford, Dodge, and GM. Alot of people now believe that the DEF is used for the regen cycle of the DPF. No, it is not. The DEF is used to turn NOx into Nitrogen. The Particulate matter trapped in the DPF is still burnt out by the injection of Diesel from the engine.

DEF just allows the SCR/DPF to go much farther between regen cycles reducing the amount of diesel spent to clean the filter.

DEF will freeze below 12* F.
 
codycarver

codycarver

Founding Wyoming Chapter Leader-retired
I was told by my service manager that every time I turn my Ford off the system is cleared and when it's started it is primed to prevent damage from freezing. I would think the other brands would have something similar??
 
mattpopp

mattpopp

Trouble Maker
codycarver said:
I was told by my service manager that every time I turn my Ford off the system is cleared and when it's started it is primed to prevent damage from freezing. I would think the other brands would have something similar??
Click to expand...

You are correct. You can hear the system running after you shut the truck down. Go stand by you furl tank next time you get out of your pickup.
 
codycarver

codycarver

Founding Wyoming Chapter Leader-retired
porthole said:
Cody, your DEF tank can freeze without damage. There is a heater in the tank.
Click to expand...
I understand. What I was referring to are the lines. The pump draws the urea from the lines and then re-primes when started again.
 
W

Willym

Well-known member
Dodge has yet to go with SCR (Selective Catalytic reduction, using Urea) The current Cummins engine in the 2500/3500 trucks uses EGR Exhaust Gas Recirculation) for NOX reduction. EGR cause "sootier" exhaust, hence the need for more frequent DPF regenerations. I've heard that Cummins is going to go to SCR next year for the 6.7 engine. The current cab/chassis units of the Ram use SCR already.


mattpopp said:
Since the introduction of DEF for our pickups, Ford, Dodge, and GM. Alot of people now believe that the DEF is used for the regen cycle of the DPF. No, it is not. The DEF is used to turn NOx into Nitrogen. The Particulate matter trapped in the DPF is still burnt out by the injection of Diesel from the engine.

DEF just allows the SCR/DPF to go much farther between regen cycles reducing the amount of diesel spent to clean the filter.

DEF will freeze below 12* F.
Click to expand...
 
mattpopp

mattpopp

Trouble Maker
Willym said:
Dodge has yet to go with SCR (Selective Catalytic reduction, using Urea) The current Cummins engine in the 2500/3500 trucks uses EGR Exhaust Gas Recirculation) for NOX reduction. EGR cause "sootier" exhaust, hence the need for more frequent DPF regenerations. I've heard that Cummins is going to go to SCR next year for the 6.7 engine. The current cab/chassis units of the Ram use SCR already.
Click to expand...

Sorry, I was speaking about their 2013 models.

SCR is typically used without urea. SCR relies on the EGR To reduce the NOx emissions because they don't typically also use urea. The old setup from dodge was a SCR system. SCR and Urea used together is a hybrid system. Attempting to use the best of both worlds.

EGR and SCR are two different functions. Dodge, Ford, and GM continue to use the SCR (DPF) to control particulate matter and they will all use Urea to control NOx.
 
Last edited:
W

Willym

Well-known member
I think that you're a little mixed up between SCR, EGR, and DPF - there sure are a lot of acronyms used nowadays! SCR and EGR are different technologies, both used for the reduction of nitrogen oxides in the exhaust stream. The former uses urea or ammonia to chemically react with the NOx's to reduce their concentration. I'm not aware of any engines using SCR without any urea or ammonia addition. The latter uses exhaust gas added to the inlet air to reduce peak combustion temperatures and so cause less NOx to be produced. The disadvantage of EGR is that it reduces combustion efficiency and causes more particulate carbon to be made. The current Cummins engine uses a hefty amount of EGR - just look at the plumbing on top of the engine. The DPF is a separate device in the exhaust pipe to filter out carbon particles, it has nothing to do with SCR or EGR. However, the DPF will fill up much faster on an engine using EGR. Hence the improvement in efficiency in the later engines using SCR.

There's a good article on SCR on Wikpedia.

mattpopp said:
Sorry, I was speaking about their 2013 models.

SCR is typically used without urea. SCR relies on the EGR To reduce the NOx emissions because they don't typically also use urea. The old setup from dodge was a SCR system. SCR and Urea used together is a hybrid system. Attempting to use the best of both worlds.

EGR and SCR are two different functions. Dodge, Ford, and GM continue to use the SCR (DPF) to control particulate matter and they will all use Urea to control NOx.
Click to expand...
 
mattpopp

mattpopp

Trouble Maker
Willym said:
I think that you're a little mixed up between SCR, EGR, and DPF - there sure are a lot of acronyms used nowadays! SCR and EGR are different technologies, both used for the reduction of nitrogen oxides in the exhaust stream. The former uses urea or ammonia to chemically react with the NOx's to reduce their concentration. I'm not aware of any engines using SCR without any urea or ammonia addition. The latter uses exhaust gas added to the inlet air to reduce peak combustion temperatures and so cause less NOx to be produced. The disadvantage of EGR is that it reduces combustion efficiency and causes more particulate carbon to be made. The current Cummins engine uses a hefty amount of EGR - just look at the plumbing on top of the engine. The DPF is a separate device in the exhaust pipe to filter out carbon particles, it has nothing to do with SCR or EGR. However, the DPF will fill up much faster on an engine using EGR. Hence the improvement in efficiency in the later engines using SCR.

There's a good article on SCR on Wikpedia.
Click to expand...

That is incorrect.
 
mattpopp

mattpopp

Trouble Maker
Ford, dodge, and GM have been using the SCR since 07. The major change was GM and Ford started to use Urea in 2011 to reduce the amount of EGR needed to control NOx. Now dodge in 2013 with the regular pickups.

SCR and EGR are two totally different systems.

SCR is used to control particulate matter. Not NOx.

Going to Urea has been a great improvement on our engines. One is the reduction of EGR needed to control NOx. With less EGR function this allows a better combustion with less incomplete combustion. Which means less soot. Less soot means less frequent regen cycles at the SCR system. Though everybody refers to that as the DPF.

Read the GM and Ford service manuals for the emissions. It is pretty clear in those manuals about this.

I have not seen one for the 2013 dodge but I assure you it will be the same.
 
W

Willym

Well-known member
I will say no more except to encourage you to read the Wikipedia article on SCR.

mattpopp said:
Ford, dodge, and GM have been using the SCR since 07. The major change was GM and Ford started to use Urea in 2011 to reduce the amount of EGR needed to control NOx. Now dodge in 2013 with the regular pickups.

SCR and EGR are two totally different systems.

SCR is used to control particulate matter. Not NOx.

Going to Urea has been a great improvement on our engines. One is the reduction of EGR needed to control NOx. With less EGR function this allows a better combustion with less incomplete combustion. Which means less soot. Less soot means less frequent regen cycles at the SCR system. Though everybody refers to that as the DPF.

Read the GM and Ford service manuals for the emissions. It is pretty clear in those manuals about this.

I have not seen one for the 2013 dodge but I assure you it will be the same.
Click to expand...
 
You must log in or register to reply here.

Similar threads

danemayer
Great ending to Diesel Exhaust Fluid problem
Replies
13
Views
91K
ILH
ILH
Top