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-   -   Diesel exhaust system regeneration (http://www.jeepforum.com/forum/f309/diesel-exhaust-system-regeneration-1955298/)

goonbash 01-03-2014 02:51 PM

Diesel exhaust system regeneration
 
I have less than 1500 miles on my 2014 diesel GC. It has gone thru the exhaust system regeneration twice so far. Is that normal ?

The evic message says continue driving at near highway speeds. Obviously you can't always do that. Both times I have continued driving and after 10-12 miles the message goes away.

As a hypothetical though: what happens if you are in a position where the exhaust regeneration process has begun but for whatever reason you have to park and shut the car off during the process? What happens?

If this process is going to happen every 700 miles like it has been then eventually I will surely be in a position at some point where I can't continue driving until the regeneration process is over like the evic message says to do.

Thanks

NC4stroker 01-03-2014 03:09 PM

Regens will vary depending on driving style. If you idle more than average, or do mainly city driving, your vehicle will go through more regens. The "magic" with highway driving and/or towing, is EGTs (exhaust gas temps) are generally higher and can "oxidize" the particulate matter which has been "caught" in the DPF (diesel particulate filter).

IF you get an EVIC message saying your DPF is xx% full, and a regen is necessary, I would drive until the regen is complete.


** As a sidebar, after reviewing the diesel supplement, if the EVIC says Exhaust Filter XX% Full Safely Drive at Highway Speeds to Remedy. I would plan on driving at highway speeds long enough for the regen to be complete.

(**Our GC diesel supplement reads very close to the Ram Cummins supplement. Evidently our vehicles can go through active regen without an EVIC message, and the EVIC only alerts us if the DPF is too full. IF you turn the vehicle off in this situation, it's no problem. This situation occurred on our GC once so far in 2200 miles, and it just smelled funny in the garage.)

So, in summation, if your EVIC says to drive at highway speeds in order for the DPF to regen, I would do that, and I would not cut off the vehicle until the EVIC says you're good to go.

JeepGC6855 01-03-2014 08:24 PM

I think the more you idle, the more the filter plugs up. In my GMC, one night I drove 200 miles on the highway the then the next day it needed to regenerate. I think with the GMC, it only does the filter cleaning when needed, thus just because it is at highway speed, it isn't cleaning the filter

Robert J. yates 01-04-2014 02:19 AM

My 08 CRD regens like clockwork every 750 miles. I wouldn't worry about it to much if you have to stop during a regen. It will try again next time you start the vehicle.

jaje 01-04-2014 08:15 AM

I don't have a scanner that informs me when my CRD is doing a regen and I just don't worry about it. Just drive it normally and it will catch up on the regen with the next long drive.

goonbash 01-04-2014 11:28 AM

Thanks. I don't idle much at all.

onebluemcm 01-05-2014 06:02 AM

We're at ~2300 miles, no regen yet. We do regular highway driving and have done one longish road trip with it so far, maybe that is the difference? Dunno. That seems excessive but only compared to our experience, n=1 doesn't mean much I admit.....

If it regens and there a no persistent indicator lights, I guess all is good.

Could a batch or two of "bad" fuel cause it to do that? Just a thought, I have no idea if it can be a factor.

NC4stroker 01-05-2014 08:07 AM

Quote:

Originally Posted by onebluemcm (Post 19120698)
We're at ~2300 miles, no regen yet. We do regular highway driving and have done one longish road trip with it so far, maybe that is the difference? Dunno. That seems excessive but only compared to our experience, n=1 doesn't mean much I admit.....

If it regens and there a no persistent indicator lights, I guess all is good.

Could a batch or two of "bad" fuel cause it to do that? Just a thought, I have no idea if it can be a factor.

When we are cruising along at road speeds, and if the EGTs (exhaust gas temps) are high enough, the 3.0 constantly cleans, or oxidizes, the trapped particles in the DPF...a process called passive regeneration. IF enough passive regeneration cannot take place the GC can go through active regen, where fuel is metered into the exhaust system, before the DPF, where the fuel ignites and "cleans" the DPF.

It seems the vehicle can go through "active" regen without alerting through the EVIC. So, likely our GCs have gone through regens without us knowing.

I noticed coming home one night on the interstate, my MPGs dropping steadily even while I cruised at road speed. I wasn't far from home, and when I got out, the whole family noted the GC smelled odd. Likely a regen.

The EVIC evidently only alerts us to an impending problem only when the particulate filter is getting clogged. This happens when driving conditions do not allow an active regen, as active regens happen at highway speeds. Higher road speeds likely aid in the regen process by allowing higher EGTS to help with the process and also keeping the under car/exhaust temps in check. (Some heavy diesel equipment can undergo stationary regens....a manual process.)

goonbash 01-06-2014 09:45 AM

Most of my driving is around our tiny town at less than 35mph so that makes sense. My diesel is probably doing active regeneration whenever I leave town and it finally sees 40mph+ speeds.

Thanks for the input.

NC4stroker 01-06-2014 10:52 AM

Quote:

Originally Posted by goonbash (Post 19153513)
Most of my driving is around our tiny town at less than 35mph so that makes sense. My diesel is probably doing active regeneration whenever I leave town and it finally sees 40mph+ speeds.

Thanks for the input.

If you could take her out on the highway, and do 75 for a few minutes a couple of times a week, that would really help the whole regen process!

My pops runs into the same thing with his Ram/Cummins. He mostly beats around town on it, and he has to do the highway thing once in a while.

I was thinking about my family in LA. The are always snarled in traffic, and it's ironic that in a part of the country full of "greenies", clean diesel technology is really not practical. I mean they would have to make a dedicated trip on the freeway to let the DPF clean itself, or the DPF would simply get too clogged, and the diesel would go into limp mode.

goonbash 01-06-2014 09:18 PM

The highway is 25 miles worth of twisty mountain roads away. No chance of doing that a couple times per week.

NC4stroker 01-07-2014 05:34 AM

Quote:

Originally Posted by goonbash (Post 19175673)
The highway is 25 miles worth of twisty mountain roads away. No chance of doing that a couple times per week.

I live in flat eastern NC. I just figure the whole world is flat! LOL

jaje 01-07-2014 06:54 AM

Quote:

Originally Posted by NC4stroker (Post 19155193)
I was thinking about my family in LA. The are always snarled in traffic, and it's ironic that in a part of the country full of "greenies", clean diesel technology is really not practical. I mean they would have to make a dedicated trip on the freeway to let the DPF clean itself, or the DPF would simply get too clogged, and the diesel would go into limp mode.

This is where hybrids do make sense like the Volt as you can run on electricity in snarled traffic. But when cruising on the highways or in a heavy vehicle they are not as efficient as a diesel. If the Volt came with a diesel generator instead of the gas engine it would get much higher than 33 MPG when batteries are depleted (so maybe Chevy will port over the now available diesel in the new Cruze into the next Volt) - it would make it a series hybrid like a locomotive engine - diesel generator with electric traction engine.

onebluemcm 01-08-2014 10:21 AM

I think I experienced some regen action today with no notification from the vehicle that it was happening. I had just filled up and was driving home, about 10 miles, on a road that has a 45mph limit and I normally get well into the 30mpgs on. It didn't want to do much better than the mid tewnties. After I shut if off in the garage I could hear that "ticking" sound you hear when a hot exhaust is cooling down and the thing definitely smelled hot. Seems like it definitely will try to take care of itself while you just happily drive along. I may have cut it off in the middle of a regen, so we'll see if there are any consequences from that.

Robert J. yates 01-08-2014 11:15 AM

FWIW... Regen on my 08WK smells like burning plastic.


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