Kia Sedona: CVVT & Camshaft Description and Operation - Cylinder Head Assembly - Engine Mechanical System - Kia Sedona YP Service ManualKia Sedona: CVVT & Camshaft Description and Operation

Third generation YP (2014-2024) / Kia Sedona YP Service Manual / Engine Mechanical System / Cylinder Head Assembly / CVVT & Camshaft Description and Operation

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). CVVT improves engine performance through reduction of pump loss, internal EGR effect, improvement of combustion stability, improvement of volumetric efficiency, and increase of 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 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.

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.

[CVVT System Mode]

(1) Low Speed / Low Load
(2) Partial Load


(3) Low Speed / High Load
(4) High Speed / High Load



Driving
Condition
Exhaust Valve
Intake Valve
Valve
Timing
Effect
Valve
Timing
Effect
(1) Low Speed
/Low Load
Completely
Advance
* Valve Under-lap
* Improvement of combustion stability
Completely
Retard
* Valve Under-lap
* Improvement of combustion stability
(2) Partial Load
Retard
* Increase of expansion work
* Reduction of pumping loss
* Reduction of HC
Retard
* Reduction of pumping loss
(3) Low Speed
/High Load
Retard
* Increase of expansion work
Advance
* Prevention of intake back flow (Improvement of volumetric efficiency)
(4) High Speed
/High Load
Advance
* Reduction of pumping loss
Retard
* Improvement of volumetric efficiency

CVVT & Camshaft Components and Components Location
Components 1. RH exhaust camshaft2. RH intake camshaft3. LH intake camshaft4. LH exhaust camshaft 1. RH exhaust CVVT2. RH intake CVVT3. LH intake CVVT4. LH exhaust CVVT ...

CVVT & Camshaft Repair procedures
Removal Continuous Variable Valve Timing (CVVT) 1. Remove the timing chain. (Refer to Timing System - "Timing Chain") 2. Remove the CVVT assembly. • A: LH exhaust CVVT • ...

Other Information:

Front Wheel Speed Sensor Components and Components Location
Components 1. Front wheel speed sensor2. Front wheel speed sensor connector ...

Good driving practices
Never move the gear shift lever from P (Park) to any other position with the accelerator pedal depressed. Never move the gear shift lever into P (Park) when the vehicle is in motion. Slow do ...

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