DPF Cleaning Off The Truck?

NC Hauler wrote:

The Mad Norsky wrote:
:h

just reading here, and one thought came to mind;

can or does anyone, make a system to add a DEF system to a truck that was manufactured without it?????

Just thinking that this DPF cleanout could be reduced if this is possible.

Gosh, to me this DPF clean out sounds complicated, off vehicle type work.

Would adding a DEF system (if even possible) be any more expensive or any less labor intensive?????????

With all the sensors and computer programming involved in the DEF system, I would think it would be quite expensive to add a DEF system to a vehicle that has DPF, but no DEF system....

That's true. A DEF or SCR (Selective Catalytic Reduction) system consists of more than just a DEF tank and the equipment to spray it into the exhaust. In order for DEF to do it's job, there must also be a specific type of catalyst installed in the exhaust system, called an SCR-CAT. Of course all the associated sensors, wiring, plumbing, and control software/hardware would have to be part of any SCR retrofit system. There are SCR retrofit kits available, but they are all intended for Over-The-Road HD and large stationary Diesel engines. They are very expensive.

The image below is a pretty good representation of the differences in the 2007-2010 Diesel emissions system, and the 2011 and up emissions system.



The left hand side is what the exhaust system on my truck (2010 F450) consists of. The right hand side is what is added to the 2011 and up Diesel exhaust systems. So, a 2011 Diesel truck will have everything shown on both sides of the image.

Diesel Oxidation Catalysts (DOC) convert carbon monoxide (CO) and hydrocarbons (HC) to carbon dioxide (CO2) and water but have little effect on nitrogen oxides (NOx). DOCs also decrease the mass of diesel particulate emissions (but not their number) by oxidizing some of the hydrocarbons that are adsorbed onto the carbon particles.

Diesel Particulate Filters (DPF) remove diesel particulate matter (PM), also called soot. Based on engine technology and application specificities, different filter technologies may be used to reduce particles emissions. I believe the type used in our trucks are called Wall-flow filters. In wall flow filters, particulate matter is removed from the exhaust by physical filtration using a honeycomb structure similar to an emissions catalyst substrate but with the channels blocked at alternate ends. The exhaust gas is thus forced to flow through the walls between the channels and the particulate matter is deposited as a soot cake on the walls. Such filters are made of ceramic (cordierite, silicon carbide or aluminium titanate) honeycomb materials.

Selective Catalytic Reduction (SCR) In the SCR system, ammonia is used as a selective reductant, in the presence of excess oxygen, to convert over 70% (up to 95%) of NO and NO2 to nitrogen over a special catalyst system. Different precursors of ammonia can be used; one of the most common option is a solution of urea in water (DEF) carefully metered from a separate tank and sprayed into the exhaust system ahead of the SCR catalyst.

In every image of a current Diesel engine exhaust system I have seen, the SCR system is always shown to be DOWNSTREAM the DOC+DPF section. This indicates to me that any benefits to the DPF of using DEF is due to the fact that the engine is not using EGR as much to reduce the Oxides of Nitrogen in the exhaust.

:):)