Solenoids or solenoid valves for variable valve timing (VVT) systems
VVT solenoids are electromechanical valves that control oil flow to the hydraulic phasers at the ends of the camshafts, whose function is either to change the valve timing or phase or, in special cases, to change the valve lift.
Because of the variable, high-speed operating conditions of an internal combustion engine, they have high electromagnetic insulation and high impedance so as not to affect the electrical control signal. Their reaction or activation time is under 0.5 ms.
They are machined to ultra-high precision to prevent the shaft and moving parts from seizing as operating temperature rises. Their seals are compatible with engine oil. The housing is stainless steel to prevent corrosion, and the core is highly corrosion-resistant since it is in permanent contact with engine oil.
Depending on the design, the solenoid has an external or attached filter, which can be cleaned with clean hot oil.
Requirements for correct installation of a CIC solenoid:
- Clean all feed and supply passages to the solenoid before installation.
- The filter must be cleaned completely with hot engine oil (60 °C).
- The electrical control circuit must be in optimal operating condition, so wiring, connectors and computer control conditions must be diagnosed before and after installation.
- Never install the solenoid without first diagnosing the VVT system and the operation of the camshaft hydraulic actuators.