http://www.turbodieselregister.com/f...eneration.html
This is in the turbodieselregister forum. It has a very comprehensive description/discussion on the regen process.
There apparently is "passive regeneration" and "active regeneration."
If I understand this correctly...
Passive regeneration is where the driving situation produces temperatures sufficiently high to burn off any soot in the DPF and keep additional soot from collecting there. Dodge says driving 50 to 60 mph (or higher) on the highway should be enough to trigger passive regeneration. Passive regens do not require additional fuel.
Active regeneration is triggered when the DPF is getting full enough to trigger the sensors. Active regeneration is where additional fuel is injected to raise the exhaust temperature to burn off the soot. This, of course, reduces fuel mileage while it is taking place. However, it should occur only when driving has not provided sufficient passive regeneration to keep the DPF adequately clear.
In other words, if you do a lot of highway driving you may rarely burn additional fuel to clean the DPF. If I understand it correctly. Only time will tell whether normal highway driving will be sufficient to avoid active regeneration.
I still don't know how to tell for sure when active regeneration is taking place. I guess I need to go ahead and get that EGT gauge soon as that seems to be the most obvious way to tell.