Nissan Variable Valve Event and Lift system (VVEL) controls the intake air mass directly via the intake valves. A rocker arm and two types of links (link A and link B in graph) close the intake valves by transferring the rotational movement of a drive shaft with an eccentric cam to the output cam. The movement of the output cam can be varied by rotating the control shaft within the DC motor and changing the fulcrums of the links. This makes a continuous adjustment of the valve lift amount possible.