KIA Niro: CVVT & Camshaft Description and operation


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, 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 increased expansion work.

This system consists of

  • the CVVT Oil Control Valve (OCV) which supplies the engine oil to the cam phaser or runs out the engine oil from the cam phaser in accordance with the ECM
    PWM (Pulse With Modulation) control signal,
  • the CVVT Oil Temperature Sensor (OTS) which measures the engine oil temperature,
  • and the Cam Phaser which varies the cam phase by using the hydraulic force of the engine oil.

The engine oil released from 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.

Operation Principle

Operation Principle

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.

  1. Intake CVVT Exhaust CVVT
  2. Exhaust CVVT

CVVT System Mode

  1. Low Speed / Low Load Partial Load
  2. Partial Load Low Speed / High Load
  3. Low Speed / High Load High Speed / High Load
  4. High Speed / High Load

CVVT & Camshaft Repair procedures


     CVVT & Camshaft Repair procedures

    Removal Warning Use fender covers to avoid damaging painted surfaces. To avoid damaging the cylinder head, wait until the engine coolant temperature drops below normal temperature (20ºC (68ºF)) before removing it. When handling a meta

     Cylinder Head Repair procedures

    Removal Engine removal is not required for this procedure. Warning Be sure to read and follow the "General Safety Information and Caution" before doing any work related with the high voltage system. Failure to follow the safety instruction

     Cylinder Head

    Inspect for flatness. Using a precision straight edge and feeler gauge, measure the contacting surface of the cylinder block and check the manifolds for warpage. If the flatness is greater than maximum, replace the cylinder head. Fla


     Electric Water Pump (EWP) Repair procedures

    Description The Hybrid Power Control Unit (HPCU) uses various semiconductors that are supplied with high voltage, hence generating more heat than engine combustion devices. Overheating can decrease the efficiency of control devices, restrict pr

     Vehicle settings (infotainment system)

    Press the Settings button on the head unit of the infotainment system. Select Vehicle and change the setting of the features. Vehicle Settings in the infotainment system provides user options for a variety of settings including door