Variable Force Solenoid - Ex (VFS - Ex)
Variable force solenoid (VFS) changes its force depending on the PWM duty to control the stroke of the CVVT oil control valve (OCV) bolt. The delivered oil rotates the rotor connected to the camshaft of the cam pager and rotates the camshaft to the engine rotating direction (exhaust retarded) or the opposite direction (exhaust advanced) to change the phase angle of the cam.