DPF Regeneration Question

[Learjet]

if you walk by the exhaust tip when it's in regen...you will know...it is HOT!

 

[kthaxton]

I'm somewhat amazed that despite all the experience on this forum, no one can give me a straight answer on this.

Yeah! What are we paying you people for?

 

[Wiredawg]

I thought most of us gave pretty good answers, based upon how much we're paid. I've only owned 6.7s in C&Cs. I've never had any message display regarding regen or DPF. I think that might be a good thing. No problems so far.

JR, the 6.7s in the C&Cs have a different cam than the p/u's. Not sure if that's all that's different.

 

[Newsa]

I've got $20 that says the 6.7's in the city buses around here also are different than the 6.7 in my 2013 2500.

Probably different turbo, possibly different cam, likely different programming to accomodate different turbo/cam.

 

[JR]

JR, the 6.7s in the C&Cs have a different cam than the p/u's. Not sure if that's all that's different.

I was referring to the bit about being certified clean idle. They're all certified to tier IV which means they're all technically "clean" The requirement for the certification is not based on what comes out the tail pipe. It is the difference between a commercial vehicle and a passenger vehicle.

 

[Wiredawg]

copy, never had it explained before. thanks.

 

[gsbrockman]

I thought most of us gave pretty good answers, based upon how much we're paid. I've only owned 6.7s in C&Cs. I've never had any message display regarding regen or DPF. I think that might be a good thing. No problems so far.

JR, the 6.7s in the C&Cs have a different cam than the p/u's. Not sure if that's all that's different.

The EGR system is totally different as well.....

 

[Wiredawg]

Yep, I knew the EGR is different and the turbo is different as well... smaller I believe. Aftermarket is great source to learn about these trucks. Turbos listed different for P/Us and C&Cs.

 

[KPear]

Not trying to be snarky, but I'm wanting to know if the DPF regeneration process will cause a count-down to limp mode if the driver cannot get to highway speeds.

The diesel supplement does in fact mention something about needing to drive at highway speeds should the DPF need an active regeneration. Here it is verbatim, in case anyone is wondering what I'm going on about:

Exhaust System — Regeneration Required Now —
Exhaust Filter XX% Full Safely Drive at Highway Speeds to Remedy will be displayed in the instrument
cluster display if the exhaust particulate filter reaches 80% of its maximum storage capacity. Under conditions of exclusive short duration and low speed driving cycles, your Cummins diesel engine and exhaust aftertreatment system may never reach the conditions required to remove the trapped PM. If this occurs, the “Exhaust Filter XX% Full Safely Drive at Highway Speeds to Remedy” message will be displayed in the instrument cluster display. If this message is displayed, you will hear one chime to assist in alerting you of this condition
• By simply driving your vehicle at highway speeds for as little as 45 minutes, you can remedy the condition in the particulate filter system and allow your Cummins diesel engine and exhaust after-treatment system to remove the trapped PM and restore the system to normal operating condition.

This is page 114 of the diesel supplement for the Ram 2500/3500 trucks. It seems pretty explicit about needing to drive at highway speeds if the dashboard warning appears.

I'm asking if anyone here has encountered that message, and if so, what will happen if you don't or can't reach highway speeds due to current driving conditions.

 

[Newsa]

As far as the descriptions go. There is no count down to limp mode for the DPF. Although there could be a warning to see the dealer if the DPF is full and several active regens doesn"t clear it. There is a count down from/for DPF for 100% full to 70% full, but that doesn't lead to an electronically programmed limp mode.

The count down to limp mode is for SCR and is mandated by government regulation.

Someone who knows alot about these engines said awhile back that "You can idle these trucks all day and not hurt them" on a different but related thread

 

[Newsa]

This info is for a 3rd gen.

But still generally relevant to our 4th gen trucks as well to my understanding and confirmed by those in the know on this 4th gen forum

https://www.turbodieselregister.com...ing-is-acceptable-says-dodge-engineer.206997/

 

[KPear]

This info is for a 3rd gen.

But still generally relevant to our 4th gen trucks as well to my understanding and confirmed by those in the know on this 4th gen forum

https://www.turbodieselregister.com...ing-is-acceptable-says-dodge-engineer.206997/

That conversation was in regards to a C&C truck....does all of that apply to a regular 2500/3500 pickup?

Also, I do think that FCA engineer ate his own words a bit on that discussion; I mean after all, those early 6.7l's without the SCR turned out to be very unreliable outside of pure highway driving.

Did the early C&C trucks have SCR from the get-go?

 

[JR]

So you can let your truck idle while Ford and GM owners have to automatically shut down after idling five minutes or risk fines in these states. "

This is strictly referencing the Clean Idle Certification, which just so happened to be implemented in 2008. It has nothing to do with best practice. C&C trucks can have different requirements to idle anyhow depending on vocational uses. But idling just to idle is not only wasteful it is not recommended.

Here's a few pictures from a 2017 6.7 engine owners manual.

Minimum operating temperature = 160*

KPear, here is one that likely pertains to your specific question. Don't know if it answers your question or not.

Changing to a more challenging duty cycle, such as highway driving.

It sounds like they are looking for sustainable elevated temps to aid in the regen process. Probably something that can't be accomplished in stop and go driving. I dont know, but suspect that if you do any type of sustained highway driving or towing your filter will not reach the 80% threshold. Assuming all components working as designed.

 

[Newsa]

That conversation was in regards to a C&C truck....does all of that apply to a regular 2500/3500 pickup?

Also, I do think that FCA engineer ate his own words a bit on that discussion; I mean after all, those early 6.7l's without the SCR turned out to be very unreliable outside of pure highway driving.

Did the early C&C trucks have SCR from the get-go?

The SCR was introduced to the 4500/5500 earlier than the 3500 to my knowledge.

But this statement is where he says it applies to both C&C and pickups

In summary he stated clearly and without any ambiguity whatsoever that owners of cab and chassis trucks and pickups can idle their trucks as long as they wish. He specifically stated we can idle them all day or all night if we want to. I asked if it should be at low idle or high idle. He stated clearly again, "it doesn't matter. "

 

[Cummins12V98]

From what I was told at the Cummins 6.7 Factory the engines are all the same except for being painted RED for other applications and programming.

 

[KPear]

The SCR was introduced to the 4500/5500 earlier than the 3500 to my knowledge.

But this statement is where he says it applies to both C&C and pickups

In summary he stated clearly and without any ambiguity whatsoever that owners of cab and chassis trucks and pickups can idle their trucks as long as they wish. He specifically stated we can idle them all day or all night if we want to. I asked if it should be at low idle or high idle. He stated clearly again, "it doesn't matter. "

Okay, but the guidance from that engineer doesn't match up with the pages you've posted....
The engineer says its okay to idle the engine for long periods of time.
The Ram literature is saying that you shouldn't idle for long periods of time and also that the SCR needs highway speeds to clean itself (I wasn't even aware that was a requirement for the SCR).

For the record, I'm not looking to idle my engine for long periods of time. If I'm using the truck, it's to go somewhere. If I'm done traveling, the engine gets turned off (I allow the turbo's to cool depending upon my usage). But if I'm in the middle of a 4x4 road and all of a sudden the DPF or SCR dashboard indicator tells me I need to drive at highway speeds, what are my options?

 

[gsbrockman]

If I'm done traveling, the engine gets turned off (I allow the turbo's to cool depending upon my usage).

You’re not one of those Sovereign Citizen guys, are ya???

 

[Newsa]

Okay, but the guidance from that engineer doesn't match up with the pages you've posted....
The engineer says its okay to idle the engine for long periods of time.
The Ram literature is saying that you shouldn't idle for long periods of time and also that the SCR needs highway speeds to clean itself (I wasn't even aware that was a requirement for the SCR).

For the record, I'm not looking to idle my engine for long periods of time. If I'm using the truck, it's to go somewhere. If I'm done traveling, the engine gets turned off (I allow the turbo's to cool depending upon my usage). But if I'm in the middle of a 4x4 road and all of a sudden the DPF or SCR dashboard indicator tells me I need to drive at highway speeds, what are my options?

Drive at hwy speeds through school zones. Sovereign citizens are not bound by any state or federal regulations.

 

[ram17]

2 ways to address your concerns. Buy an OBDII (about $40) and download OBD Fusion ($4.99) onto your smart phone then go to this thread ---- “New” 2018 2500 Ram. One of the members here has created a user define PID that allows you to anticipate when the next regen will occur. If your DPF is around 98% you will know that a regen will start shortly and you can plan accordingly. I suspect that RPM is the important factor not vehicle speed so if you are four wheeling go in 4 LO and/or manually adjust the transmission gear to keep the RPMs up. My active gens last about 15-20 mins.

 

[Learjet]

I can see when regen last occurred, is about to occur and is in active regen with my Scangauge II