Urea/regen?

[TRAMPLINEMAN]

With the new trucks that use urea, do they still regen? All of our newer trucks at work that don't use urea have a manual regen button on the dash. We just got a new Ford F-750 dump truck with a 6. 7 Cummins that uses urea and I noticed there is no regen button. The truck manual does not mention anything about regen. Just curious, I don't know much about this.

 

[HBarlow]

I believe the urea system avoids the need for regen of a dpf.

 

[firemansdiesel]

The Urea System= less EGR circulation, but you still have a DPF that needs regening.

 

[HBarlow]

I thought the use of the new urea injection system eliminated the dpf! If the new ones require a dpf and wasted fuel to cook it plus purchasing urea that seems even worse than the earlier ISB6. 7s.

 

[Hoefler]

I believe Urea is used to clean the DPF by chemical reaction.

 

[HBarlow]

I believe Urea is used to clean the DPF by chemical reaction.

That would make sense. I guess I should do a little searching to try to learn the details.

 

[HBarlow]

Here is a nickles worth of explanation. It makes sense:

What Is Urea Injection? | eHow.com

You were correct, Hoefler. Thanks.

Edit:

Ooops! The simple explanation I just posted says the urea injection system is downstream of the dpf so apparently regen is still required to periodically clean the soot out of the dpf.

That sounds like an additional stage of soot removal instead of replacing an existing component with another more efficient one. According to the simple little explanation above urea freezes at 11* so it requires a heater so the urea system is just added cost and complexity and more complicated crap to fail and cause needed diagnosis, replacement, or repair.

 

[dlmetzger]

Urea is not used to reduce PM (particulate matter, soot) in a DPF (diesel particulate filter). It is used reduce NOx emissions. Urea breaks down into NH3 which reacts with NOx (which is a combination of NO, NO2 & NO3, nitrogen oxides) to produce HO2 (water) and N2 as final exhaust products.

 

[HBarlow]

Yeah, you are correct.

I read all the links I could find in a google search. All state that the scr systems using urea are for the purpose of additional NOx reduction from the exhaust. They are installed downstream of the dpf so obviously the regen procedures we are already familiar with will continue.

According to some of the links I read Dodge will use expensive exotic metals like palladium in a catalyst to remove NOx in pickups but the less expensive SCR system requiring use of DEF in chassis cabs.

GM and Furd will use DEF in all diesel trucks.

What I could not find an explanation of is whether the scr urea system replaces the egr device used on ISB6. 7 engines from 07. 5 through '09. Perhaps it does?

Can an owner of a new '10 or '11 answer that question?
'

 

[Mikey-KE7LBB]

No $6/gal "synthetic pee" in regular pickups in '11 or '12 models... Only CC trucks '11 and newer from all of my reading on this forum and others.



Probably gonna get my post deleted by the mods, but... Here goes:



It's required for all Class 7/8 trucks beginning with '07 model year and NEEDED to compensate for engineering shortcomings in Chevy (Car Hardly Ever Vacates Yard)/GMC (Gay Man's Chevy) and Ford (F***er Only Runs Downhill) for now at least :-laf

 

[TRAMPLINEMAN]

Thanks for the info. I know the truck has a dpf, but it just seemed weird to me that there isn't a manaul regen button or an idiot light in the cluster for regen. Thanks again.



This new truck also has another gauge in the cluster next to the fuel gauge. It's a full/empty gauge that we all thought was for the dpf filter, again nothing in the manaul. We figured that when it read full, it needed to regen. Wrong! It's the urea tank gauge. When it reads empty, the truck shuts down. Not so handy when you're stuck in 2 feet of mud in a farmers field in the middle of nowhere and the brand new truck you just got is in limp mode.

 

[Bob4x4]

The Dodges do not shut down when they run out of Def but they will not restart,maybe the bigger trucks are the same??

 

[Bob4x4]

The Diesel Exhaust Fluid Emissions system uses a Selective Catalytic Reduction (SCR). This is a technology that uses a urea based Diesel Exhaust Fluid (DEF) and a catalytic converter to significantly reduce nitrous oxides (NOx) emissions. The system accomplishes this by injecting small quantities of Diesel Exhaust Fluid (DEF) into the Selective Catalytic Reduction (SCR) where its vaporizes and decomposes to form ammonia and carbon dioxide. The Diesel Exhaust Fluid (DEF) Dosing Control unit is used to control the operation and monitoring of the DEF system. The ammonia is the desired by-product which in conjunction to the SCR Catalyst, converts the NOx to a harmless nitrogen and water. The SCR system is equipped with two NOx Sensors and modules that are used to monitor the efficiency of the SCR Catalyst and DEF system.

 

[TRAMPLINEMAN]

We have two of these trucks and tried it on both. We ran both of them completely out of urea and they both went into limp mode. The trucks still ran, but would not move.