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Just wanted to set the record straight here about the Cummins DEF system. DEF doesn't have any effect on the DPF because DEF is injected post-DPF, and DEF has nothing to do with particulate reduction. It only helps to convert harmful gases into harmless nitrogen (N2) and water (H2O). The DPF still catches particles, and the system will still go into regen. The manual says that you need to drive at freeway speeds for 45 minutes to clear out the filter.
Here's a video on how the Cummins SCR system works. It's a 2010 video, because this system was first implemented on 2011 model year Ram chassis cab trucks. 2010 Cummins Aftertreatment System Animation - YouTube
If you'd like to learn more about DEF itself and the chemical process that happens when DEF is injected into the exhaust, check out this PDF: http://www.cumminsfiltration.com/pdfs/product_lit/americas_brochures/MB10033.pdf
I'm about a month away from receiving my new truck, and I've been doing a lot of research on this DEF system over the past 8 months to determine if it was better or worse to go with a 2013 or a 2012. The claim is that the 2013 trucks should get better fuel mileage, but we'll see how that goes. The additional cost of DEF is minimal. It's used at a 50:1 diesel to DEF ratio. This means that for every 50 gallons of diesel fuel used, the system uses roughly one gallon of DEF. If Diesel is $3.60 (today's price at my station around the corner), that means if you were to spend $180 on diesel, you'll now spend $182.79. My closest truck stop with DEF sells it for $2.79/gallon. Overall cost of operation increases by 1.5%. Equivalent to a 4 cent increase in the cost of diesel from $3.60/gallon.
While some like to consider this a "liberal" system, and indeed since it's a "save the earth" hippie thing, that's somewhat true, if you've ever been to a country where diesel is heavily subsidized, and over half the vehicles are spewing black smoke in your face as they drive by, these are systems that may not make your butt-dyno happy, but they will reduce overall emissions, and give diesels a better image overall, and give us cleaner local air, even if the planet itself is already fūcked. The claim is that with this system, the engine has near-zero emissions. Lower than many of today's gasoline engines. As for repair costs, only the future will tell. I think the ultimate question is whether or not the DEF system is part of the powertrain warranty.
Man you're good! Are you sure you aren't a Ram truck designer in disguise?
Pick me pick me! I think I got the system down pretty well! lol
Dodge trucks use a diesel particulate filter (DPF) on their diesel trucks.
Unlike powerstroke and duramax, which use a DEF system, cummins dont need any extra fluid for their systems.
The filter takes the particulate out of the exhaust. As the filter fills up with particulate it needs to go into regeneration before it gets full.
There are two types of regeneration, active and passive.
Active regeneration uses diesel fuel as a catalyst to raise the temperature and burn out the particulate (this is where a DPF system differs from a DEF system, DEF systems use a seperate DEF fluid as a catalyst) Active regeneration can use over a gallon of diesel fuel to burn out the particulate.
Passive regeneration is when the exhaust gas temperatures are high enough to burn out the particulate on its own without the help of a catalyst. Passive regeneration is the reason why you here people say that you need to work these new trucks hard and basically beat on them (particulate burns at around 600*C or about 1100*F, most sled pullers and high hp diesel guys cut their EGTs off around 1300*F)
As long as you dont allow the filter to fill up you shouldnt have to replace the filters or have any problems. Unfortunatly these trucks dont always go into active regen like they should, the filters become full and clogged and the truck goes into limp mode, making you go slowly to the dealership for a $1000-$1500 replacement filter
Any more questions hit me!