Abstract: Methods and systems are provided for monitoring and controlling a cylinder valve deactivation mechanism. In one example, a method may include sending a lower command signal to a cylinder deactivation valve control (CDVC) system without actuating a cylinder valve transition, determining an impedance of a solenoid of the CDVC system while sending the lower command signal, and actuating the cylinder valve transition responsive to the determined impedance by sending a higher command signal to the CDVC system. In this way, the cylinder valve transition is performed when the impedance is high enough to prevent over-current.

Abstract: A variable cam timing system in an engine is provided. The variable cam timing system includes a camshaft receiving rotational input from a crankshaft. The camshaft includes a valve cam rotationally actuating a valve coupled to a cylinder and a null cam actuating a null follower including a null spring exerting a return force on the null cam during interaction between the null cam and the null follower, where the null follower is independent from the cylinder.

Abstract: A variable cam timing system in an engine is provided. The variable cam timing system includes a camshaft receiving rotational input from a crankshaft. The camshaft includes a valve cam rotationally actuating a valve coupled to a cylinder and a null cam actuating a null follower including a null spring exerting a return force on the null cam during interaction between the null cam and the null follower, where the null follower is independent from the cylinder.