Originally Posted By: whip
Is it dumping the fuel into the exhaust? In HD trucks, the regen is done while parked, and the engine runs at high RPM to burn off the soot.
As explained on one of the diesel forms (and I believe the mixture is ran really rich--I do not think it has a separate exhaust injector), but the regens occur while driving and not parked. This would make sense from an MPG point of view--the OTR trucks are getting zero MPG while parked doing regens. I am assuming Ford (and the other OEMs) are seeking to maintain some level of fleet economy and as long as it works...
Originally Posted By: PaintedHorse (TheDieselSpot)
Your truck will regen in two different processes, Depending on conditions.
The first is an Active Regen. This is triggered by a Soot % in the DPF. If a regen starts and does not complete. No big deal. Lets assume the trigger point is 2.70%, The previous regen reduced soot down to 1.90% before it was terminated by you shutting off the engine. Next time you start and drive. A regen will not start again until you hit the trigger point of 2.70%. That may be 5 miles down the road if you are heavy footed and creating lots of soot, or it may be 1000 miles from now.
The second type of regen is a Passive Regen, This happens automatically when ever your exhaust temps exceed 572°. This type of regen will last as long as your exhaust temps stay above that 572°. It may be for 30 seconds or it may be for 10 hours. Normal freeway driving at 70 mph = about 470-490° So to hit the 572° you will need to be climbing a grade, towing a trailer, accelerating. The point is the DPF is fully capable of doing many very short or long regens, It doesn't damage or destroy the DPF to do a short regen.
If you develop soot that doesn't get cleaned off, You will get a "DRIVE TO CLEAN" message. It will stay lit up on your dash until you have driven far enough to clean your DPF.