Hyundai Elantra (CN7): Exhaust Emission Control System / CVVT (Continuous Variable Valve Timing) System

Continuous Variable Valve Timing (CVVT) system advances or retards the valve timing of the intake and exhaust valve in accordance with the ECM control signal which is calculated by the engine speed and load.

By controlling CVVT, the valve over-lap or under-lap occurs, which makes better fuel economy and reduces exhaust gases (NOx, HC). CVVT improves engine performance through reduction of pump loss, internal EGR effect, improvement of combustion stability, improvement of volumetric efficiency, and increase of expansion work.

This system consists of:

The engine oil released from the CVVT oil control valve varies the cam phase in the direction (Intake Advance/Exhaust Retard) or in the opposite direction (Intake Retard/Exhaust Advance) of the engine rotation by rotating the rotor connected to the camshaft inside the cam phaser.

The CVVT has the mechanism of rotating the rotor vane with hydraulic force generated by the engine oil supplied to the advance or retard chamber in accordance with the CVVT oil control valve control.

[CVVT System Mode]