The Electromechanically Deactivating Valve Train—From Concept to Mass Production in a Modular Engine Family

Switchable roller finger follower systems are state-of-the-art in modern engines but often suffer from hydraulic actuation. Schaeffler developed an electromechanically switchable roller finger follower system for the application in the new modular BMW inline six and inline four-cylinder engines for the usage in mild hybrid powertrains with P1 electric machine. The system enables the deactivation of the exhaust valves to cut off oxygen flow to the catalyst, reduce drag torque in overrun mode, increase recuperation and even enables electric driving in mild hybrid applications. Details of the system design including the application to the four and six-cylinder engines are described, as well as several new production processes which were developed to realize the system in a high-volume production.