General Motors And Delphi Working On Revolutionary Cylinder-Deactivation Technology

Sean Szymkowski

It will most likely be quite some time before mass adaptation of alternative-fuel, or electric vehicles, takes hold. Until then, it’s a race against the clock to develop the next big thing in powertrain technology to make vehicles more efficient, and even more frugal, especially larger SUVs and trucks.

General Motors announced it had invested in Silicon Valley software startup, Tula Technologies, but it was not known what GM had in store with the investment. It’s become clear after Delphi and GM showed off what could be the next greatest innovation: Dynamic Skip Fire, or DSF.

How it works is DSF is applied to each individual cylinder, and it continuously varies which cylinders must be firing, as it works in sync with the engine’s throttle system. In normal engines, the flap in the throttle body is almost always in a closed position but, with DSF, the flap is nearly always open to control the engine’s power by varying the number of cylinders needed.

The cylinders are shut off by stopping the flow of oil with special valve lifters on each cylinder.

“The more power you need out of your engine, the more torque, the harder you press down on the accelerator pedal, the greater percentage of your cylinders will fire. This is software-enabled variable displacement,” Tula CEO, Scott Bailey, told Automotive News.

Tula says a V8-powered SUV typically only requires 30 hp to cruise on a highway to hold its speed and, with DSF, six cylinders shut down to provide a monumental 21-percent increase in fuel economy, as tested in the real world on a GMC Yukon Denali.

GM Authority