ENGINE MANAGEMENT SYSTEM – V 18-2-44 DESCRIPTION AND OPERATION Variable Camshaft Control Electronic Control The following describes the electronic control of the VCC system. Electronic Control The engine control module is responsible for activating a VCC variable position solenoid valve based on EMS program mapping. The activation parameters are influenced by the following input signals: l Engine speed l Load (intake air mass) l Engine temperature l Camshaft position. Mechanical Control The position of the solenoid valve directs the hydraulic flow of engine oil. The controlled oil flow acts on the mechanical components of VCC system to position the camshaft. The hydraulic engine oil flow is directed through advance or retard activation oil ports by the VCC solenoid. Each port exits into a sealed chamber on the opposite sides of a control piston. In its default position the oil flow is directed to the rear surface of the piston. This pulls the helical gear forward and maintains the retarded valve timing position. When the oil flow is directed to the front surface of the piston, the oil pushes the helical gear in the opposite direction which rotates the matched helical gearing connected to the camshaft. The angled teeth of the helical gears cause the pushing movement to be converted into a rotational movement. The rotational movement is added to the turning of the camshaft providing the variable camshaft positioning.