CVVT Oil Control Valve (OCV) Description and Operation

Description

The Continuous Variable Valve Timing (CVVT) system advances or retards the valve timing of the intake and exhaust valves according to the control signal from the ECM, which is calculated based on engine speed and load. CVVT control provides valve overlap or underlap, which improves fuel economy, reduces exhaust emissions (NOx, HC), and improves engine performance by reducing pumping losses, internal exhaust gas recirculation effect, improving combustion stability, improving volumetric efficiency, and increasing expansion work. This system consists of: - CVVT Oil Control Valve (OCV), which supplies engine oil to the cam phaser or shuts off engine oil from the cam phaser according to the PWM (Pulse Width Modulation) control signal from the ECM, - CVVT Oil Temperature Sensor (OTS), which measures engine oil temperature, - and Cam Phaser, which changes the camshaft phase using engine oil hydraulic pressure. Engine oil flowing from the CVVT oil control valve changes the camshaft phase in the direction of rotation of the engine (intake advance/exhaust retard) or in the opposite direction (intake retard/exhaust advance) by rotating the rotor connected to the camshaft inside the cam phaser.