Diesel engines typically return great gas mileage – for example, the new turbodiesel 3.0L I-6 LM2 Duramax offered in the 2021 Cadillac Escalade is tipped to be substantially more efficient than the SUV’s standard gasoline-powered V8. However, it’s now looking like several GM diesel engines may adopt new technology to make them even fuel-efficient in the near future.
The tech in question is Dynamic Skip Fire (DSF), also known as Dynamic Fuel Management (DFM) in General Motors lingo. According to a GM Authority source who worked on GM diesel engines, it’s very much possible that DFM technology may see adoption with the 3.0L I-6 LM2 Duramax and 6.6 V8 L5P Duramax turbodiesel powerplants.
While far from an official confirmation, it’s still an interesting prospect. There are currently no GM diesel engines that utilize DFM technology – rather, the first GM engines to adopt the tech were the 5.3L V8 L84 and 6.2L V8 L87 gas-powered engines for the 2019 and newer Chevrolet Silverado 1500 and GMC Sierra 1500.
Now, Cummins is adopting similar technology on its diesel engines, and it’s possible GM could follow suit with its own oil burners. According to our source, the new strategy will be used primarily to reduce emissions, although vehicles are sure to see a bump in fuel economy as well.
That said, the Trump administration has put forth a rollback on vehicle emission regulations, which could weaken GM’s ambitions to bring the tech to its diesel engine lineup.
For now, General Motors has yet to announce anything that could indicate a move to adopt DFM technology on any GM diesel engine. As always, we’ll keep our ear to the ground in case that changes.
What do you think, dear reader? Would DFM tech be a good fit for GM diesel engines? Let us know in the comments, and make sure to subscribe to GM Authority for ongoing GM news coverage.
Comments
Over a non AFM engine DSF engines see an almost 15% increase in economy. I don’t know if you will see that high of an increase, but it would still help. What would help more would actually be the emissions benefit. If it significantly decreases emissions, there is a lot of power and efficiency on tap that could then be harnessed. If that’s the case, economy increases of as high as 20% could be observed. I also like DSF for what it does to ring wear. AFM vehicles note that upon rebuild that the deactivated cylinders exhibit almost no wear and the active cylinders exhibit normal wear. A DSF vehicle should double ring life.
To me it just makes modern diesel engines even less desirable. I drive an older 24 valve Cummins, there is no def, no particulate filter, not even a catalytic converter. All of these additional economy and emissions systems add lots of cost and complexity. Diesels used to be great because of how simple they were, it made them extremely robust, reliable, and relatively low maintenance costs. All those advantages are gone now, and with the ultra low sulfur diesel the fuel cost advantage is long gone as well. I can’t find any reason to justify a diesel when I replace my truck, the towing performance is the main advantage left for diesels and I don’t tow often enough to offset all of the other negatives.
Is skip-fire effective enough to just eliminate the need for exhaust fluid? The complexity from a jake brake is already there. So, it could be a net win.
I’m afraid DEF is hear to stay. It is mandated under CAFE. Does anyone know if the new SAFE emissions guidelines require it? I would be fine with even going back to regen to avoid DEF.
If that is possible then I agree that could be a good tradeoff
If cylinder de-activation is necessary, DSF is the way to go. It’s been in the mix for a while and I’ve not heard of, nor read any complaints about it. It’s definitely better than GMs original AFM which had its problems. I can’t see why it wouldn’t be doable on a diesel with a modern common rail fuel injection system.
As noted above modern engine complexity is a double edge sword: when the technology works, its great to be alive! But when there’s problems and nobody has a clue what to do, one yearns for the day of GMs early 60s tech 250 six.
I couldn’t stand AFM but after driving a new Silverado with DFM (DSF) for a few thousand miles, it’s a really good system. I could always tell when AFM kicked in but the new system is so smooth it’s really hard to tell it’s even skipping cylinders.
I would keep it as is for a few more years before exploring elaborate new tech. Establish the market and see what happens with the economy.
By all accounts, this motor appears to be excellent. I would hate to see their 3.0L diesel ruined by AFM style issues.
Part of the appeal of diesels is longevity.
AFM and DSF work almost entirely differently to achieve the same ends. AFM used oil pressure to activate the lifter dissengagement, DSK uses electronic solenoids, almost like a gun trigger. It’s faster, simpler and has already been extensively tested. GM claimed they put 7 million miles on the new truck engines before releasing the new truck. I don’t know how many trucks they tested and how the motor break down was, but they made a point to have a 300000+ engine in their trucks
If they still stink, ban them.
I owned dirty diesels in the past, now have to suffer with them stinking up the company parking lot.
Your stinking truck is probably a ford. Chevy or GM is the ONLY WAY TO PROCEED!!!
I’ll proceed with my brand new GMC TERRAIN, thank you very much.
Excelente, gracias,
Water methanol injection still the best choice. Lower emissions less DEF use, higher fuel economy more torque more horsepower. No mechanical changes to engine retain original OEM reliability.
GM use to make the most reliable Diesel engine known to man. They were two stroke and lasted forever. They would have something if they could put a 671 in a pickup.
There was a time when GM made the finest Diesel engine known to man. If they could fit a 471 or 671 in a pickup, they would have something.