DPF Regen Process - Operational Question

[FLSteve]

Here is a question I have, and it may only relate to a Spartan Chassis ... my DPF regen process has happened about four (4) times since we have had the coach (about 15,000 miles on it now) and each time the cycle lasts about one (1) hour. So far it has always finished, and the light goes off before we reach our stop for the night as it usually happens when we are on an interstate.

So here is my question ... what if we reach our stop before the cycle finishes? Is it ok to just shut off the engine and hope it will finish when the engine is restarted the next day ... or should I leave the engine running until the cycle is over? For example, what if the regen process starts 10 minutes before we want to stop.

Just want to be ready if this ever happens to me. FYI, I posted this question on the FB Newmar Owners Group and am getting very mixed responses ... kind of like the jacks down/slides out/what comes first question.

FLSteve

 

[Neal]

I've heard from others that Spartan academy says pass your exit and keep on driving - I wholeheartedly disagree with this.

A REGEN only requires about 1000 RPM, it's all about maintaining a temp. If it were me, doesn't matter the chassis, I would not turn off the engine until it's complete. It will just be in a high idle until done. It could take an hour. Just don't park over dry grass or leaves or be in a fuel lane.

 

[MrsSquid]

I can't remember if it was Spartan or Cummins. We were told to leave the engine running. You could park in a clear area, no tall grasses, etc. So far, every time we've exited the highway at our exit, before we've reached our actual stop, the regen process has shut itself off. We've seen it pick up again on the next highway trip. Hope that helps. For further reassurance you could confirm with Cummins after the holidays. As you said you get all sorts of answers on the forums.

 

[Rich W.]

Either way is fine because as long as it senses enough differential pressure between the inlet and outlet of the DPF it’s going to start a regen as soon as conditions are right (engine rpm, road speed, and exhaust temp). So if its in the middle of a regen while you're at highway speed and you interupt it by getting off, whether for fuel for 30 minutes, or overnight or longer, and it has not burned off enough soot, it will start again as soon as conditions allow. Spartan may be saying “keep driving” to be on the safe side, but it isn’t necessary.

What you don’t want to do is continue to drive at low speeds (under about 55mph) for an extended period of time (more than a couple hours) because at some point the system will give up trying to regen and put you into derate. This is from the system designers to keep you from ignoring the issue, potentially damaging your DPF, and of course causing permenant injury to the planet, just like the low DEF issue. I’ve read you have as much as four hours to perform a regen once the lamp illuminates, but as @Neal recently found, this can sneak up on you pretty fast. It shouldn’t and I don’t know why his did - I would have said it wouldn’t and been wrong.

All that said, I’m a firm believer in the more regens the better, and I have several adjuncts to perform them manually. So if its at all feasible, I’d give it the opportunity to finish a regen any time the sensors initiate one, although I would probably not pass my exit and just drive until its done, because I can easily perform a manual regen. As far as I know, it can’t finish an active regen on its own once you stop. Maybe Spartan added this feature, but I’ve never read any accounts of a regen self-initiating when parked - it will always wait until driving conditions are right again, or for manual initiation if parked. It can’t detect if you are in a safe location so by design, it won’t start on its own unless you are driving.

There are three stages or regen: passive which is just the process of soot burning off in the DPF when exhaust temp is high enough (around 700°, no dash indicators, no diesel injected into the exhaust), active which includes the injection of diesel while driving (1100° +, high exhaust temp, still no DPF lamps on unless you slow down or stop), and parked/forced/manual regen (they may even be other names for it but its all the same thing) where the operator finds a safe place to perform a regen and has the time to sit for an hour or so, and initiates the regen either by a switch on the dash (truckers), the “shorting plug” (FL chassis coaches for a number of years - not sure on new ones), or with an external device that plugs into the J1939 port and has regen capabilities. But Spartan may have devised and installed other means for the operator to start a regen - I don’t know.

It doesn’t surprise me that you are getting a variety of opinions elsewhere (especially on FB which is probably the worst place to get any information on anything), because there is so little training or preparation for new owners of these systems and usually people are forced into guesswork when a problem arises. Truckers learn all about this in trucker school, but when have you ever known a dealership to pair a customer with a competent, qualified tech to provide an in-service on these things? If they did, half the potential buyers would probably walk, and that’s assuming the dealership has any qualified people to educate you on the process.

So that’s my .02 worth on this. I’ve done everything but attend a class on these systems (including replacing a differential pressure sensor) and I still haven’t ruled out the class. These are complex, fragile systems forced on consumers before the technology was ready for the mobile environment so we are stuck either figuring them out or risking a tow and paying the the big bucks to fix them. Fortunately, 10 years after this form of emissions control was introduced, they are finally starting to operate more reliably. But they can still leave you stranded, so the more you know about it, the better.

Edit: Looking at your dash I don’t see the industry standard HEST or After-treatment DPF lamps, so it appears Spartan has done away with this in favor of a ”clear text” approach (maybe all glass dashes?). This is the first I’ve seen of it, but it also tells me there may be other differences on a Spartan Chassis. They certainly took a different approach on their DEF heads over the years, much to the detriment of coach owners. I’m guessing DTE 700mi is the DEF Tank Empty indicator - another difference. So a call to Spartan would be a good idea, and maybe you can provide more info based on their response.

 

[Neal]

What you don’t want to do is continue to drive at low speeds (under about 55mph) for an extended period of time (more than a couple hours) because at some point the system will give up trying to regen and put you into derate.

I'm not sure I agree with this. Otherwise how would we ever be able to do a regen while parked as was done to clear my issue in Breckenridge? I think as long as the params are met for it to do a regen it will be fine and we've seen that it doesn't take much. I also think the system is smart enough that quite frankly we don't need to know when it's doing regens and it's probably scaring more people than not and the system will manage itself. The problem is when the system tells you that you need to do a regen, but it's not in regen, and then it goes into derate like mine did. It's been discussed that Spartan does active regens so they see the light more often than FL owners as FL does passive regens. I'm no expert on this but sadly I've been forced to learn.

I certainly won't drive without this tool and will be doing forced regens probably twice a year for good measure. I never want to have happen what happened to me on Labor day with a derate.

 

[Rich W.]

I'm not sure I agree with this. Otherwise how would we ever be able to do a regen while parked as was done to clear my issue in Breckenridge? I think as long as the params are met for it to do a regen it will be fine and we've seen that it doesn't take much. I also think the system is smart enough that quite frankly we don't need to know when it's doing regens and it's probably scaring more people than not and the system will manage itself. The problem is when the system tells you that you need to do a regen, but it's not in regen, and then it goes into derate like mine did. It's been discussed that Spartan does active regens so they see the light more often than FL owners as FL does passive regens. I'm no expert on this but sadly I've been forced to learn.

I certainly won't drive without this tool and will be doing forced regens probably twice a year for good measure. I never want to have happen what happened to me on Labor day with a derate.

FL also does active regens while driving just like Spartan, but only when conditions are correct, and you won’t see the indicators unless you interrupt it. If it has initiated an active regen and you interupt it by slowing or stopping (dash lamps come on and it dings), the literature states you have about 4 hours or x miles (I don’t recall exactly) to get back up to speed and let it finish before the derate process begins. If you are on the cruise control during an active regen, you’d never notice, but if you decelerate below a certain point, you’d see the dash lights and get the ding. I’ve pushed it to about two hours successfully but I wouldn’t go beyond that. The indicators tell you it was in active regen, you interrupted it, and it wants you to drive in such a manner that it can complete it. If you can’t, then its parked regen time.

To answer your question, it can’t do a parked regen on its own - you have to find a safe place to park, and then manually initiate the regen, either by the shorting plug, or some other adjunct, or get it back into active regen by driving it under the right conditions. It won’t start a parked regen on its own because it doesn’t know if the area you parked in is safe. And it probably can’t start an active regen again by driving if you are already in severe derate because it won’t go fast enough or develop high enough exhaust temp. How was your regen in Breckenridge performed? If I remember right, you tried the shorting plug and that didn’t work, so you had a mobile tech come out? So you were already in severe (50% or more) derate, correct?

What I don’t understand with your episode is why it went in to derate so quickly. I drove for a couple hours on a two-lane highway with it constantly starting and stopping an active re-gen, interrupted (dash lights and annoying “ding”) every time I slowed for a sharp turn, reduced speed for a small town, or stopped for a stop sign - this process probably happened 30+ times. I finally found a place to park and did a forced (parked, manual…) regen, but it never went into derate as far as I could tell - maybe the first 25% as that wouldn’t have been obvious to me under the conditions. But it seems yours was rather sudden and severe and that should not be the case.

The system does require some operator involvement, hence the indicators and, on coaches, the shorting plug. On OTR trucks, theres a switch on the dash, and truckers just use that when its regen time. I can only guess that coach manufacturers decided that since typical RV owners don’t have the training, they shouldn't be trusted with a regen switch on the dash, but if they can figure out the shorting plug, they must be good to go. Obviously I don’t agree because this has led to numerous strandings, expensive tows, and visits to repair facilities for something that, with a little in-service for the operator, would be completely unnecessary. It’s a very poor adaptation of a commercial transport emissions system to the private market.

And I agree - I don’t leave home without a DPF regen adjunct as I don’t want to rely on the shorting plug. I bought mine here: Used Items used for 1/2 price and I couldn’t tell it from new. They are only randomly available used so you’d have to keep checking the website. I also have the Diesel Decoder for reading live data. My OTR Diagnostics subscription just ended so I’m going to rely on these two devices for now and see how it goes.

The functional difference between OTR and Diesel Decoder for live data is that OTR just displays 30-40 pertinent parameters and Disel Decoder shows seemingly everything - 100’s of parameters so you have to dig through pages to find what you're looking for. Its much more interesting but also somewhat cumbersome. The other difference is that the DD is a one time cost for the device and then you use a free app. OTR is subscription based at $600/yr. But OTR also does forced regens and now you can use it in areas with no internet. You just need to log on again within two weeks to keep the subscription current.

 

[Neal]

What I don’t understand with your episode is why it went in to derate so quickly.

I think I was at soot level max and it was done. It choked itself (sts). Why it didn't do regens to prevent getting to this point we will never know, my belief is ALTITUDE. If I'm going to higher altitude destinations (over 5K) then I'll be doing a forced regen prior to going to higher elevation.

 

[Rich W.]

I think I was at soot level max and it was done. It choked itself (sts). Why it didn't do regens to prevent getting to this point we will never know, my belief is ALTITUDE. If I'm going to higher altitude destinations (over 5K) then I'll be doing a forced regen prior to going to higher elevation.

The altitude question is really worth some research. I’ve never heard it discussed and the system should compensate, but it seems your’s didn’t.

 

[flarider]

Hi Steve,

I haven't read all the posts yet. But my 2018 DSDP does Regen often. After the first year When I went to Spartan Academy I asked about it. I told them I would be driving on the highway for hours at 65+ and thought it was strange it was Regening. They said at highway speed you can drop it into 5 gear and that would bring the RPMs up 1950-2000 which is better than 1800 in 6 gear. But either way is fine and if it Regens and you need to stop that is fine it will start up again if it is needed.

For those that say don't stop if you are in a regen. It doesn't make sense to me because if you have to slow down or stop for traffic the regen will stop at low RPMs

 

[Rich W.]

I’m sure this has been posted here before but its a good refresher. Pages 98 to 102 (don’t worry, it starts on 94) more or less address this question.

http://www.ourmotorhome.net/2017/docs/DPF_Regen_instructions.pdf