Chevrolet introduced its efficiency-enhancing Active Fuel Management (AFM) cylinder deactivation system in 2005 and has now followed up with even more sophisticated Dynamic Fuel Management (DFM). While AFM alternates between eight- and four-cylinder operation, DFM features 17 cylinder patterns that constantly determine how many cylinders are required to meet real-time driving needs.
Dynamic Fuel Management uses a sophisticated controller that continuously monitors every movement of the accelerator pedal, running a complex sequence of calculations to determine how many cylinders are required to meet the required torque. It makes this determinations 80 times-per-second to optimize efficiency and power delivery at all speeds. with only the cylinders needed to provide this torque in play…down to a single cylinder.
An electromechanical system controls all 16 of the engine’s hydraulic valve lifters, using solenoids to deliver oil pressure to control ports in the lifters that activate or deactivate the lifters’ latching mechanisms. When a cylinder is deactivated, the two-piece lifters effectively collapse on themselves to prevent opening the valves. When the cylinder is reactivated, solenoids send an oil pressure signal to the control ports on the lifters and the latching mechanism restores normal function, allowing the valves to open and close.
The first application of GM’s Dynamic Fuel Management emerged in the 2019 model year, available on the all-new Chevrolet Silverado’s optional 5.3-liter and 6.2-liter V-8 engines. This efficiency-enhancing system will certainly find its way to additional models across the GM line. Chevrolet says DFM improves fuel economy by about 5 percent.