Passive Re-Gen?

[Hook'em_Horns!]

So, with the DPF on the LMM motor, it reaches a stage when measured flow against resistance triggers a Re-Gen cycle. It is stated that temps reach 1100*F to burn off the particulates.

My question is this, if you're workin' it hard pulling heavy on the highway and elevating your EGTs, wouldn't you in fact have a passive Re-Gen going on with the DPF, thereby using less fuel overall?

[toypuller]

Yes and no if that makes any sense. When pulling you are getting egts of maybe 1000-1200, When its in regen it heats the dpf filter to around 1700 is what our description and operation states. So when towing you are using more fuel, causing more soot, causing it to regen more.

[Hook'em_Horns!]

I C...I was using 1100 as that is stated in the medium duty showroom brochure as the burn point.

If a higher temp is needed, then the jump from 1100 would require less fuel for a shorter period of time to complete the re-gen, wouldn't it? Are the higher than 1100 temps seen a result of more fuel being dumped from a cooler EGT starting point?

My quest is, towing re-gens may use less fuel for shorter durations, yet may have more cycles per tank, or not. Are more particulates forced through in stop and go driving versus steady boost cruise on the open road? I think so.

Just theorizing out loud here...

[08DMAXX]

Help me understand better... when a regen occurs extra fuel is put into the exhaust to heat the dpf to the needed temps.... The extra fuel comes from the injectors? Does it inject it on the exhaust stroke? How does it only heat the dpf to that temp and not everything else? I wouldn't want my turbo seeing 1700 degrees. I appologize if this is dumb question just trying to understand what happens. Thanks guys.

[08DMAXX]

Hook'em I can see what your saying

[usafracer]

If I understand the system correctly most of the heat is created in the DOC. There is a catalyst that reacts with the un-burnt fuel causing the high temps. The fuel is injected on the exhaust stroke and yes it does heat the turbo but not to the point of hurting it. If I am wrong someone please correct me.

[toypuller]

Yes what usafracer said. I could not have said it better.

[Speedpro1]

Aren't you still using about 3 gallons of fuel every time it regens?

[usafracer]

3 gal is the max it will use according to the dealer. I was told that it would not use that much every time. That is just the worse case.

[Speedpro1]

Originally Posted by usafracer

3 gal is the max it will use according to the dealer. I was told that it would not use that much every time. That is just the worse case.

I'm going to do some checking myself. Now you have me thinking!