Dynamic Skip Fire: GM hopes to use cylinder management tech to increase efficiency by 15%

Cylinder deactivation, the act of shutting off predetermined arrangements of pistons to save fuel, is nothing new.

Also called variable displacement, the engine management system has existed in concept form for decades, and today, you’ll find variants of it in newer cars from Honda, Mercedes-Benz, Audi, and General Motors.

With the help of Silicon Valley startup Tula Technology, GM is looking to take the fuel savings one step further by employing something called Dynamic Skip Fire (DSF).

Instead of shutting off entire cylinder banks, DSF analyzes each piston individually, determining whether to ignite or bypass it based on the driver’s throttle input and torque demands. According to the automaker, the system has shown fuel savings of up to 15 percent when compared to an engine without cylinder deactivation.

“This technology holds the potential to improve fuel economy on select GM vehicles without degrading power capability when it’s required,” said GM Chief Technical Officer Jon Lauckner. “This joint effort combines software expertise from Silicon Valley with powertrain expertise from General Motors.”

DSF is primarily a software-based approach. However, in order for it to work, the engine must already have cylinder deactivation hardware installed. There are always concerns about vibration when altering the firing order, but GM claims the technology avoids excessive reverberation while providing the required engine torque.

The program is still in the testing stages, but with fuel efficiency standards rising, Tula Technology and GM seem committed to making DSF production-ready.

“We’ve worked closely with GM during this exciting stage of DSF development, and they’ve provided essential financial support while allowing us to run our business with full autonomy,” said R. Scott Bailey, CEO of Tula Technology. “Our goal is the same as GM; we both innovate to make the lives of people better.”