General Motors, in partnership with Delphi and the Silicon Valley start-up Tula, has been working on a new-generation cylinder-deactivation system for its gasoline engines for years.
The technology, the prototype of which was unveiled in 2015, is known as Dynamic Fuel Management (DFM). At the time, they were projecting a release in 2020. But now we’ve learned that Chevrolet will feature this revolutionary technology in the brand-new 2019 Chevrolet Silverado’s V8 engines. That’s one year earlier than expected!
Dynamic Fuel Management 101
For the past few years, the management system for the 5.3- and 6.2-litre V8s has deactivated four of the eight cylinders in certain driving conditions. The system always acts on the same cylinders—1 and 7 on one side of the engine block and 4 and 6 on the other—following very specific parameters to favour fuel economy.
Although this system works well, GM, like all other auto makers, is striving to improve fuel economy even further.
Since the mechanical components already exist—namely the lockable hydraulic push-rods and control solenoids—and have proven their worth, why not use them on all of the cylinders? It seems so simple, you wonder why they didn’t think of it before!
Always deactivating the same cylinders has the enormous advantage of predictability, which helps balance the engine. But when you decide to deactivate any of the eight cylinders and more than half the engine, things can get complicated fast.
Vibrations are the Number-one Enemy
The real challenge is determining how many cylinders to deactivate—and which ones—during the engine cycle without causing violent jolts. When the workload is light and only a small part of the total power is needed, an engine can function with fewer than four active cylinders. But how to you pull it off?
The key is highly sophisticated programming. It practically takes a miracle to deactivate as many cylinders as necessary following a sequence that helps counter jolts and vibrations. And to top it all off, the DFM system can even run the engine using just one cylinder! If you’ve already experienced the shaking and vibrations produced by a misfiring spark plug or injector, you know this is no small feat.
The new generation DFM system is slashing fuel economy. Preliminary data indicates significant improvements to the tune of 9% to 15%. What’s more, they didn’t need to develop new parts and are using existing mechanical components. The world premiere of this major technological advancement is coming soon in the Chevrolet Silverado.
We’re looking forward to seeing this development and, more importantly, test driving it over the course of the year.