Diesel's Not Done Yet: Cummins Explores Cylinder Deactivation

Steph Willems
by Steph Willems

Despite the switch to low-sulfur fuel and ever more stringent emissions regulations around the world, compression ignition technology still gets a bad rap, tarnishing the remaining crop of diesel engine offerings despite their fuel economy advantages.

In the world of heavy duty pickups and large commercial vehicles, it’s a case of diesel or what else? Electric motors powered by battery banks the size of a refrigerator warehouse? Gotta use what works.

Diesel engine maker Cummins sees plenty of life left in the technology, and believes better is possible. If gasoline engines can shut down cylinders at will to conserve fuel, why not oil burners?

With that in mind, the company has teamed up with Tula Technologies, a major purveyor of engine management software, to bring cylinder deactivation to big, burly diesels. On Wednesday, both companies announced findings of their collaboration on diesel Dynamic Skip Fire (dDSF) — the diesel version of the technology General Motors adopted on its gasoline V8s under the name Dynamic Fuel Management.

With dDSF, Cummins says an X15 (6.7-liter) inline-six test engine returned significant reductions in CO2 and smog-generating NOX emissions when fitted in a semi-truck, in addition to better fuel economy.

“We will continue to innovate the diesel engine system to make it lighter, more reliable, powerful and fuel-efficient, and we are encouraged by the progress demonstrated in this collaboration and what it could mean for future diesel technology,” said Lisa Farrell, Cummins’ director of advanced system integration, in a statement.

Cummins already markets the X15 as the thriftiest diesel in its weighty class, with the six-pot generating up to 500 horsepower and 1,850 lb-ft of torque. With Dynamic Skip Fire, the engine would fire only the number of cylinders needed for by-the-second load requirements. If adopted on diesels big and small, the advantages for cost-conscious fleet operators and makers of heavy duty pickups, both of whom are staring down the barrel of new emissions regulations, are obvious.

“Our partnership with Cummins has given us the opportunity to expand our DSF technology beyond its success in gasoline engines,” said R. Scott Bailey, president and CEO of Tula Technology. “Demonstrating the capability to improve fuel efficiency while also achieving very effective emissions control is extremely important for all diesel engine applications in the future.”

In a joint release, the two companies said “the collaboration will continue with exploring future system optimization and viability to control noise, vibration and harshness in commercial vehicle applications.”

[Image: Toa55/Shutterstock, Cummins]

Steph Willems
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  • ThomasSchiffer ThomasSchiffer on Apr 23, 2020

    I will continue to drive Diesels as long as they are available. For my driving needs and style there’s nothing else that comes close to providing fuel economy combined with spirited fast driving on the Autobahn. No gasoline engine (much less an EV) can offer those long legs while sipping so little fuel. And this article is a bit misleading. Diesels are still very much popular in Europe, they’re considered even cleaner than gasoline engines (the modern EURO6 Diesels). Several studies have shown that the air which comes out of the tailpipe of a modern Diesel car is cleaner than what is sucked in at the front.

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    • DenverMike DenverMike on Apr 24, 2020

      @dal20402 Try inhaling a lung-full of Euro6 exhaust directly at the tailpipe end. I did and it's still complete death compared to normal air. I don't have a death wish, but just take my word for it. No, I was strapping down a diesel BMW after loading in on to a 4 ft high flatbed. I forgot the engine was still running and inhaled just as I got to the back of the right rear tire. Talk about gag. I'm sure it took minutes or hours off my lifespan.

  • DieselTechForum DieselTechForum on Apr 29, 2020

    why is it that the author or page editors choose such a ridiculous and non representative image of a smoking pick up truck for this story that is about efficiency and improving emissions? One must wonder if it is a bias against diesel, that smokey trucks get more clicks than others or just laziness. Come on TTAC- get real with your images-- it cuts way down on any journalistic integrity when there is such a poor choice of images to go with a story. How about some 'splainin on how and why that image was chosen?

  • JK I grew up with Dodge trucks in the US, and now live in Turin, Italy, the home of Fiat. I don't think Italians view this as an Italian company either. There are constant news articles and protests about how stalantis is moving operations out of Italy. Jeep is strangely popular here though. I think last time I looked at stelantis's numbers, Jeep was the only thing saving them from big big problems.
  • Bd2 Oh yeah, funny how Trumpers (much less the Orange Con, himself) are perfectly willing to throw away the Constitution...
  • Bd2 Geeze, Anal sure likes to spread his drivelA huge problem was Fisher and his wife - who overspent when they were flush with cash and repeatedly did things ad hoc and didn't listen to their employees (who had more experience when it came to auto manufacturing, engineering, etc).
  • Tassos My Colleague Mike B bought one of these (the 300 SEL, same champagne color) new around June 1990. I thought he paid $50k originally but recently he told me it was $62k. At that time my Accord 1990 Coupe LX cost new, all included, $15k. So today the same car means $150k for the S class and $35k-40k for the Accord. So those %0 or 62k , these were NOT worthless, Idiot Joe Biden devalued dollars, so he paid AN ARM AND A LEG. And he babied the car, he really loved it, despite its very weak I6 engine with a mere 177 HP and 188 LBFT, and kept it forever. By the time he asked me to drive it (to take him to the dealer because his worthless POS Buick Rainier "SUV" needed expensive repairs (yes, it was a cheap Buick but he had to shell out thousands), the car needed a lot of suspension work, it drove like an awful clunker. He ended up donating it after 30 years or so. THIS POS is no different, and much older. Its CHEAPSKATE owner should ALSO donate it to charity instead of trying to make a few measly bucks off its CARCASS. Pathetic!
  • RHD The re-paint looks like it was done with a four-inch paintbrush. As far as VWs go, it's a rebadged Seat... which is still kind of a VW, made in Mexico from a Complete Knock-Down kit. 28 years in Mexico being driven like a flogged mule while wearing that ridiculous rear spoiler is a tough life, but it has actually survived... It's unique (to us), weird, funky (very funky), and certainly not worth over five grand plus the headaches of trying to get it across the border and registered at the local DMV.