Eaton has been chosen to supply an electromechanical actuation system (EMAS) that can deliver an early intake valve closing (EIVC) to the China-based automaker Great Wall for use in a line of hybrid-electric vehicles (HEV).

The Eaton EMAS is a discrete valvetrain-based technology that allows manufacturers to select the intake lift that best fits the engine map. At low to medium engine speed and torque, the system delivers the EIVC function, reducing the air trapped in the cylinder and the pumping losses, which increases overall engine efficiency.

When the engine requires maximum performance, the system switches to the longer valve event, delivering the highest output possible. Leveraging a system that can be easily integrated into the valvetrain and the cylinder head space and controlled by a simple electric actuator, the EMAS creates a balance between fuel economy and performance.

Eaton’s new system differs from traditional variable valve actuation (VVA) solutions in that it includes switchable rockers, a mechanical actuation shaft controlling the switching of the rockers, and an electric actuator driving the actuation system on demand. This configuration makes the system unaffected by varying oil temperatures, which enables fast system switching across a very wide working range of the engine. This also enables a safe rocker switch at high engine speed.

“Our EMAS was conceived to be easily scaled and a minor modification of the mechanical link between the actuator and rocker arms allows the system to be used in all engine families from three to six cylinders. The switchable rocker arm is composed of stamped and cold-formed parts, which helps manufacturability without impacting performance.

—Alessio Lorenzon, global engineering manager, Valves, Eaton’s Mobility Group