LegendaryLawman
Legendary Pessimist
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We need to get you a job in .gov.
Ram Heavy Duty Forum
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Regen
- Thread starter Glassman
- Start date
I wonder why Cummins, specifically, was targeted, and is responsible for paying the fines for the emissions debacle on the Ram trucks, and paying for the extended warranty coverage of the DEF after treatment system (for 2013-2018) and ALL of the emissions components (for 2019)…
Could be there is more to the Stellantis / Cummins business relationship than we as consumers know……..
My theory:
Because it’s 100% Cummins software for both the engine and emissions. Cummins sells it to Ram and Ram slaps their sticker on it and calls it proprietary but it really isn’t. It’s a Cummins Engine, with a Cummins ECM, and Cummins software disguised as “Ram”. The most that Ram does is take the software and map it to their trucks so that the integration is seamless. Thats why you get the various Regeneration messages and intervention notices the same as any commercial truck running the B6.7 commercial engine. The only difference is instead of the various indicator lights on the dash, you get pop-up messages. That’s the part where Ram makes their revision. When the EPA litigation started, ultimately it was a Cummins product and Cummins tuning that was at fault and they were the sole liable party. Ram stood back and washed their hands of it, likely claiming they had no idea that the NOx sensor strategy wasn’t correct.
(This is also why I think Ram / STAR struggle with the diagnostics on these regen frequency trucks because they don’t have a fully in-depth understanding and have to pass stuff along to Cummins for advisory services)
If you read through the documents Cummins has on their B6.7 commercial engine, pretty much every feature carries over on to the Ram platform, just in a different “disguise”
Some of the details mentioned above would also explain why some of these trucks that operate continuously in short-trip / low-speed duty cycles end up having issues. I don’t think the regeneration cycles are necessarily kicking in due to the low system temperatures (below 550°F). They also have carry over to all the driver alert notices, just in EVIC messages instead of the lights on the dash.
Some of the details mentioned above would also explain why some of these trucks that operate continuously in short-trip / low-speed duty cycles end up having issues. I don’t think the regeneration cycles are necessarily kicking in due to the low system temperatures (below 550°F). They also have carry over to all the driver alert notices, just in EVIC messages instead of the lights on the dash.
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I’ve wondered that same thing.
On a certain level that applies to most engines with a DPF. I don’t know about timer based regens on other diesels, but passive and active regen is all linked to to the same temps.
I have to wonder how small diesels, like in the JL/JT, do with city driving.
Of course.
But there are distinct parallels between how Cummins manages the commercial 6.7 and how Ram manages the FCA version. It’s not the temperatures I’m referring to (as you said those don’t change from engine to engine) it’s the strategies that are all the same as far as I can tell.
I believe the small engines like the JK / JT and other brands like the TDI all have much easier times with this stuff due to the significantly lower horsepower and torque. A 90HP Jetta is working hard enough to move the vehicle that the engine is at a higher load under most normal operating conditions so it much easier to get EGT’s up for passive (and active) regeneration.
OLEJOE
Well-Known Member
I 100% believe the load percentage factor is the clue. The higher the load , the higher the heat and egt’s. The 13-18 trucks, the 3.42 was the standard drive axle ratio. Now its 3.73. The gear change helped with the pulling but dropped the percentage of work load on the engine when empty.
The previous generation DOC / DPF’s were also different. Higher flowing and less restriction, which leads to easier passive regeneration / active regeneration, and less plugging. My 2017 3500 DrW was a 3.73 and had ZERO emissions issues throughout the course of its life. Sold it with 80k on it and never once did it trigger any DTC’s for emissions system failure or malfunction. I saw one check engine light in 80,000 miles and it was due to a stuck open thermostat that caused the truck to run cooler than the expected value. I regret ever selling that truck.
OLEJOE
Well-Known Member
I had an 18 2500 that I kick my self for getting rid of. Had the 4 wd actuator, an engine fan and the hydra boost module go out but had zero engine or emissions problems.
So far my 22 has only had recalls but several of those.
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I see similar DPF delta pressure between the ‘18 and ‘22. The ‘22 does run cooler EGTs a lot of the time and that’s reducing passive regen. Gearing will play a factor with certain types of driving.
OLEJOE
Well-Known Member
We used to drop a gear when the EGT’s got up to 1250* on the 290’s and 335’s in the big rigs.
The lower gear reduces the load factor, raises the rpm and increases the air flow.
The lower gear reduces the load factor, raises the rpm and increases the air flow.
Man yall are having me think. I’m looking at 3500 trucks to build for some exploring an daily work. I’m looking at a couple brand new 2023s and one 2022 HO. Should I pass on the 2022? Are HOs just as prone to this issue? I live sort of out in country where it’s a good 10+ mins of 50 mph zones then highway. Approximately 35% of driving will be purely city stop and go.
Based on my data collection, there does not seem to be any correlation between engine output and the regen issue.
In terms of model year, that does seem to have some more pronounced trend. The 2022’s seem to be the most commonly affected model year.
Thank you for sharing your wealth of knowledge and data!
Guess I have a choice. The 22 is an HO Laramie with 7k, already had transmission replaced due to snap ring failure, $63k. 2023 standard output Laramie $68k or 23 Big Horn standard output $63k. Feel like the HO is a good buy, but a potential nightmare of issues. I was hoping to not delete this one but I could I guess if it becomes too much of an issue
Not sure I agree with this. It takes a given amount of energy to move a given load, regardless of the drive axle ratio. The impact of the 3.42 vs. the 3.73 (or the 3.73 vs. the 4.10) occurs mostly at the max load limit. The 4.10 will have slightly higher applied torque (pulling capability) under high loads. For anything below max load, you would hope and expect the transmission strategy to optimize engine RPM. The 3.73 should cause the engine to downshift sooner. The resultant RPM might be the same in either case. With the 4.10 you might pull the RV up the hill in 6th. With the 3.73, it might downshift to 5th and give the same RPM and the same load on the engine.
From thinking about this, I'm wondering whether the extra money I paid for the 4.10 was worth it. With a modern automatic transmission, I'm not sure it makes much difference. It probably reduces gear shifting a bit when pulling in 6th, but I'm not sure it does much else.
OLEJOE
Well-Known Member
I disagree with your disagreement. It takes the same amount of energy to move the same load at the same rpm. The engine develops more torque at an increased rpm. Most people having regen problems don’t have issues towing because the amount of fuel is increased to maintain the same speed and it increases the EGT’s. True the transmission can compensate for the lower or higher gearing to a point. It has to take more energy to move x number of lbs at 1600 rpm vs the same load at 1700 rpm running the same mph. All of these theories are just that. Theories
Fuel consumption is not a direct linear relationship to RPM. An engine will only develop the torque needed to pull the load. The torque required at 1,500 RPM with a 3.73 is exactly the torque needed at 1,650 RPM with a 4.10 - the speed will be the same. If you increase torque without increasing load, the speed will increase. Pulling a given load at 1,500 RPM with a 3.73 will probably take about the same fuel as pulling it at 1,650 with a 4.10 (assuming the transmission doesn’t downshift with the 3.73 and put you at 1,650 RPM anyway). Physics is an unforgiving bitch. Mass x distance = energy required. Operating in the relatively flat efficiency bands of these engines will use about the same amount of fuel and put the same load on the engine. And if the 4.10 does require slightly more fuel, won’t that raise EGTs, not lower them?
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OLEJOE
Well-Known Member
I agree with the first part but I think the 4.10 would deliver better mpg than the 3.73 simply because the engine is in less of a bind. I believe (and I can’t prove it) that the 3.42 trucks ran a little higher egt’s than the 3.73’s do and that in certain situations is why the 3.73 trucks don’t passively regen as easily. All speculation.
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The difference always occurs, since 4.10’s have 9.9% more torque multiplication than 3.73’s… all the time.
5th with 3.73s is no the same at 6th with 4.10, so there will be a rpm difference given the same speed and tire size.
You can’t shift below 1st, so yes the 4.10’s are worth it for getting the the load moving. Then once moving the 4.10’s require less engine torque for the same wheel torque in the same gear so less strain. If you tow the 4.10’s are worth it.