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Diesel exhaust regen set bumper on fire!

flan said:
Injected into the cylinder, and burned there. As far as I know the only diesel that injects diesel into the exhaust post turbo is the (junk) caterpillars with the ARD head.
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H3LZSN1P3R said:
Not on these trucks its not injected into the exhaust
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You are both correct, however, I never said fuel was injected into the exhaust. Re-read my post.
I posted to clarify that fuel is injected to activate a passive regen and the reason why.
 
John Jensen said:
You are both correct, however, I never said fuel was injected into the exhaust. Re-read my post.
I posted to clarify that fuel is injected to activate a passive regen and the reason why.
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Your post left room for interpretation that was the reason I posted, and probably why Mr Sniper did as well. No biggie.;)
 
sstoner911 said:
With the trailers - I suspect this happens when the trailer is being backed in and the truck exhaust is to close to the corners(when truck is 45 degrees)of the trailers and perhaps left idling for extended period of time. All the melting seems to happen on the passenger side but this doesn't mean it happened while towing - its just to far away.
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John Jensen said:
Fuel is injected. Not to clean the filter, to raise the exhaust temps.

Active regeneration - is triggered when the DPF exhaust back-pressure reaches a certain back pressure point and is interpreted as 80% soot for the 6.7. Then the ECU initiates a fuel injection designed to increase the exhaust temperature in the DPF to over 662 degrees F in order to oxidize the particulate deposits. When completed, the ECU assumes a some small amount of residual soot and resets the value to 9%.
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Thank you for the facts.
tyler2you said:
Some interesting data on actual exhaust temperatures on DPF equipped vehicles:

https://www.fs.fed.us/eng/pubs/pdf/08511816.pdf
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That scientific publication shows data that suggests temps near 800° at the outlet on a 5500 model. That's over 150° higher than Fiat says it gets internally.
 
John Jensen said:
You are both correct, however, I never said fuel was injected into the exhaust. Re-read my post.
I posted to clarify that fuel is injected to activate a passive regen and the reason why.
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Your reply was to the talk about injecting in to the exhaust i think thats where i got the confusion
 
I wonder why Ram doesn’t run exhaust cooler when GM and Ford do. The report posted earlier indicated a significant drop in temp. with the cooler.


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Are you able to see EGT levels on these trucks during regen and compare them to what is normal? Cruising, idling, WOT EGT?

800 degrees is not terribly hot for a diesel IMO depending on where it’s measured. My old 01 Cummins would kiss 1000 degrees under sustained WOT or loaded towing conditions up hill. It had RV injectors and an upgraded HX35 turbo (from the stock HY) but other than that fueling was stock. EGT probe located in manifold collector.

I’d imagine regen would have to get things quite a bit hotter?
 
I've seen this happen on equipment...
One with an injector (fuel) at the DPF, it over fueled
The DPF bricks broke apart and pieces came out as sparks/spray, melted some plastic
Before they had DEF quality sensors, someone would have put fuel the DEF tank.

Most stuff anymore has a lot of fail safes so if one parameter isn't correct it will shut the entire operation down. This is with off-road equipment I would imagine on-road vehicles have as much or more going on.
 
jetrinka said:
Are you able to see EGT levels on these trucks during regen and compare them to what is normal? Cruising, idling, WOT EGT?

800 degrees is not terribly hot for a diesel IMO depending on where it’s measured. My old 01 Cummins would kiss 1000 degrees under sustained WOT or loaded towing conditions up hill. It had RV injectors and an upgraded HX35 turbo (from the stock HY) but other than that fueling was stock. EGT probe located in manifold collector.

I’d imagine regen would have to get things quite a bit hotter?
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That was up in the manifold tho...by the time it gets all the way to the exhaust tip it's significantly cooler...
 
AJ608 said:
I've seen this happen on equipment...
One with an injector (fuel) at the DPF, it over fueled
The DPF bricks broke apart and pieces came out as sparks/spray, melted some plastic
Before they had DEF quality sensors, someone would have put fuel the DEF tank.

Most stuff anymore has a lot of fail safes so if one parameter isn't correct it will shut the entire operation down. This is with off-road equipment I would imagine on-road vehicles have as much or more going on.
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Yup.... remember when Ford first added the split tailpipe after the dpf? there were flames coming out of the exhaust tip....
 
IndyRamDRW said:
That was up in the manifold tho...by the time it gets all the way to the exhaust tip it's significantly cooler...
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It cools some going through the turbo then heats up after the cat then heats up after the dpf then cools through the scr the temps are much hotter after the manifold in newer diesels its interesting seeing the different numbers on all the EGT probes
 
Here is an easy solution and a very affordable visual modification. $34 on Amazon for a 4" to 6" bolt on exhaust tip that you can extend your exhaust gasses out into the airflow with. I have mine pushed onto the pipe so that the tip exit is just even with the outermost bulge of the dually fender lines, so this should mix the exhaust gasses into the passing airflow and reduce the concentrated air temp compared to the stock tailpipe that exists a bit inside of the planer airflow path. I could easily loosen the clamp bolt and pull it outward almost 10" more if I wanted to get crazy with it. I may pull it 3" more out from the truck when I hook to the fifth wheel camper just to get it into more turbulent airflow and get more temp reduction.

Link to Amazon is below. It is a 30 second direct fit install.

$34 Black or Stainless 4" to 6" bolt on exhaust tip.
 

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IndyRamDRW said:
That was up in the manifold tho...by the time it gets all the way to the exhaust tip it's significantly cooler...
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Thats my point though, that in order for the tip temps to get to the point of doing this the regen process would have to be seriously hot.
 
NOTE:
I want to thank everyone for posting on this. I appreciate all the input.
I will post more pictures as soon as the weather lets me get my truck clean enough.
 
flan said:
No other plastic melted closest to the tailpipe, but burnt wires up near the damage. Electrical fire?
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Darkone said:
Yea i agree I would expect the molding along the bottom of the bumper and the mud flap to have some degree of excessive heat.
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Or, the crosswind forced the extreme heat into a pocket, swirling above all the lower stuff, and that melted/burned the rear facia harness.
This is definitely not an unbelievable circumstance that happened.
 
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