Join Date: Mar 2019
Location: Calgary, Alberta
I did a bit of research on this a while ago while I was considering a delete, and with the newer systems the raw fuel is injected into the exhaust stroke (on all cylinders), however it does NOT combust there increasing temperatures on the engine and turbo. So you shouldn't see much of an increase in oil or EGT at the heads during regen on these, or 6.7 engines. It's a tricky feat of engineering and chemistry, but the fuel mapping will change during a regen allowing for increased excess oxygen in the exhaust (EGR will close during this, and DEF use will increase to counteract the increased NOX production which results from higher cylinder temperatures), you will get slightly higher cylinder temperatures due to this, but this would only be due to the EGR being shut down and greater availability of oxygen. The key to it all is the Diesel Oxidation Catalyist (DOC); The raw hydrocarbons from the fuel injected on the exhaust stroke combine with the excess oxygen in the exhaust, and when this hits the DOC, the hydrocarbons oxidize at this point to create the heat to clean the DPF. Once I learned this, my concerns with the DPF went away knowing that it doesn't hurt your engine in the same way that the older systems did (i.e. 6.4).
With that i'm much more comfortable running the system until there is a major issue with the DPF system that would cost a lot to fix... for example if i had the choice to delete, or replace the DOC and DPF, I would just delete at that point to save money - but ford says you should be good to 200,000 miles or something like that. As for the added soot from the EGR system, you can counteract this with more regular oil changes to make sure nothing major builds up, but the new oil formulations are excellent at suspending soot particles, where any larger ones that can affect engine wear are easily removed by the filter. Another thing that i hear often is that the fuel being added gets washed off the cylinder walls and dilutes the oil... well the 24000 psi injection on these engines basically fully atomizes the fuel, so it's not like it's spraying in liquid form on the cylinder walls... it's essentially a gas at that temperature which is easily pushed out during the exhaust stroke. There may be a minuscule amount that makes it into the engine oil, but if you change your oil regularly, this will never be enough to affect your viscosity, and just in case I use a 5W40 oil to ensure there will be no issues from that. In the end, if you're not looking to tune your engine for big power or something like that, leave the system in place and change your oil regularly, and it should be reliable for a long time.
As an environmental scientist i'm also happy to do this from an air quality standpoint, as fine particulate matter is terrible for the lungs and contributes significantly to cancer rates, and NOx is terrible for all of your lungs, smog, and acid rain.. With the system in place, you're emissions are down 20-100 fold over a non DPF/EGR engine. Another thing that I like to see is when I look into my tail pipe vs say that of an ecoboost (or any turbo gasoline engine for that matter), my pipe is clean as a whistle and theirs are black. Soot production is a result of too much fuel and not enough air in the mix, so these engines produce lots of soot as well off the line before your turbo spools up enough to supply adequate air... So it may only be a matter of time before DPF is needed on gas engines as well.