Hyundai Elantra MD/UD: CVVT Oil Control Valve (OCV). Description
and Operation
Description
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) and improves engine
performance through reduction of pumping loss, internal EGR effect, improvement
of combustion stability, improvement of volumetric efficiency, and increase
of expansion work.
This system consist of
-the CVVT Oil Control Valve (OCV) which regulates the engine oil to and
from the cam phaser in accordance with the ECM PWM (Pulse With Modulation) control
signal,
-and the Cam Phaser which varies the cam phase by using the hydraulic
force of the engine oil.
The engine oil getting out of the CVVT oil control valve varies the cam
phase in the direction (Intake Advance/Exhaust Retard) or opposite direction
(Intake Retard/Exhaust Advance) of the engine rotation by rotating the rotor
connected with the camshaft inside the cam phaser.
