General Motors Company [NYSE:GM] continues to make refinements to its Chevrolet Silverado 1500 and GMC Sierra 1500, with the latest update being the availability of a new mild-hybrid system. Known as eAssist at GM, the mild-hybrid system used on the popular pickup trucks leverages technology developed for the Chevrolet Volt and is said to improve fuel efficiency by as much as 13 percent.

Designed for the 355-horsepower 5.3-liter V-8 offered with the trucks, which already features fuel-saving features such as direct injection, variable valve timing, cylinder deactivation and an available eight-speed automatic, eAssist adds a small electric motor and lithium-ion battery. The battery is charged using energy recovered under braking. It’s a 0.45-kilowatt-hour unit that adds about 100 pounds to the vehicle’s curb weight.

CHECK OUT: Meet Hennessey's 1,032-HP Dodge Charger SRT Hellcat

Energy stored in the battery is used by the electric motor to aid the engine by providing a power boost—up to 13 horsepower and 44 pound-feet of torque—during acceleration and passing and also enabling the engine to operate in four-cylinder mode for longer periods. The electric motor is also used to restart the engine which can now be switched off when the vehicle is at a stop light or in heavy traffic.

2016 Chevrolet Silverado 1500 eAssist

2016 Chevrolet Silverado 1500 eAssist

Further efficiency gains come from aero enhancements aimed at reducing drag. According to GM, a 6.0 percent improvement in aerodynamic efficiency is made possible due to a standard soft tonneau cover and automatic grille shutters designed to close at speeds over 30 mph.

ALSO SEE: The Bugatti Vision GT Concept Sounds So Glorious It Makes Angels Cry: Video

The eAssist system for the Silverado and Sierra is most effective when driving around town. With the eAssist system, the Silverado and Sierra return 18 mpg city, 24 highway (and 20 mpg combined). That’s an improvement of 2 mpg in the city, as well as 1 mpg better in the highway and combined figures.

The cost of adding eAssist is only $500 but at present it’s limited to only a few pricey trim levels. However, GM plans to expand its availability for 2017.


Follow Motor Authority on Facebook and Twitter.