Continuously Variable Valve Timing (CVVT) System: Description

The CVVT (Continuously Variable Valve Timing) which is installed on the exhaust camshaft, controls intake valve open and close timing in order to improve engine performance.

The intake valve timing is optimized by CVVT system depending on engine RPM.

This CVVT system improves fuel efficiency and reduces NOx emissions at all levels of engine speed, vehicle speed, and engine load by EGR effect because of valve over-lap optimization.

The CVVT changes the phase of the intake camshaft via oil pressure.

It changes the intake valve timing continuously.

Fig 1: Illustrating CVVT Operation

Courtesy of KIA MOTORS AMERICA, INC.

Fig 2: CVVT Operation Chart

Courtesy of KIA MOTORS AMERICA, INC.