Hyundai Santa Cruz: Cylinder Head Assembly / CVVT & Camshaft

- Description [Electric E-CVVT] Electric E-CVVT system is electric continuous variable valve timing system. It is located on the intake camshaft of the engine and uses motor rotation to control the rotation angle of camshaft relative to the rotation of crankshaft regardless of engine pressure. E-CVVT controls the DC motor current (duty signal) to more closely control the system compared to the previous pressure type, to increase reaction speed of cam, to improve startability, and to reduce the emission of exhaust gas. Also, operation range of intake valve (valve opening angle) is expanded. So, the output and fuel efficiency are improved. - Operation [Electric E-CVVT]

[Center OCV TYPE CVVT] The CVVT has the mechanism rotating the rotor vane with hydraulic pressure generated by the engine oil supplied to the advancing or retarding chamber through the CVVT Oil Control valve (OCV).

   

• The variable force solenoid (VFS) changes its force depending on the PWM duty to control the stroke of the OCV.

• It also controls the lock, unlock, advanced, retarded, and holding functions.

[CVVT System Mode]

(1) Low Speed / Low Load	(2) Part 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	Neutral	* Valve Under-lap * Improvement of combustion stability
(2) Part Load	Retard	* Reduction of HC	Retard	* Reduction of pumping loss by retarding the intake valve closing timing
(3) Low Speed /High Load	Completely Advance	* Reduction of pumping loss	Advance	* Improvement of volumetric efficiency
(4) High Speed /High Load	Completely Advance	* Reduction of pumping loss	Advance	* Improvement of volumetric efficiency