CVVT Oil Control Valve (OCV) - Description and Operation

Description

The Continuous Variable Valve Timing (CVVT) system advances or retards the intake and exhaust valve timing according to the control signal from the ECM, which is calculated based on engine speed and load. Under CVVT control, valve overlap or underlap is achieved, which provides better fuel economy, reduces exhaust emissions (NOx, HC), and improves engine performance by reducing pumping losses, internal EGR 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 drains engine oil from the cam phaser according to the ECM PWM (Pulse Width Modulation) control signal, - CVVT Oil Temperature Sensor (OTS), which measures the engine oil temperature, - and a cam phaser, which changes the camshaft phase using the hydraulic pressure of the engine oil. Engine oil supplied through the CVVT oil control valve changes the camshaft phase in the advance direction (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.