Kia Rio: CVVT (Continuously Variable Valve Timing) System: 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 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.

Catalytic Converter

Description The catalytic converter of the gasoline engine is a three way catalyst. It oxidizes carbon monoxide and hydrocarbons (HC), and separates oxygen from the oxides of nitrogen (NOx). ...

CVVT (Continuously Variable Valve Timing) System: Operation Principle

The CVVT has the mechanism 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 con ...

See also:

Rear Wheel Speed Sensor Inspection
1. Measure the output voltage between the terminal of the wheel speed sensor and the body ground.    ...

Passenger Airbag (PAB) Module Removal
1. Disconnect the battery negative cable and wait for at least thirty seconds before beginning work. 2. Remove the glove box housing. ...

Compression Pressure Inspection
   If there is lack of power, excessive oil consumption or poor fuel economy, measure the compression pressure. ...