The CVVL (Continuously Variable Valve Lift) system is a device that can continuously control the valve lift depending on the operating conditions.
As shown below, conventional engines control air intake quantity using throttle valve.
But, the CVVL engine controls air intake quantity through the valve lift control with the throttle valve always opened.
Advantages of the CVVL system are as follows:
Improved engine performance at all driving areas through control of valve lift
Pumping Los reduction / Fuel efficiency increase through restriction of the use of the throttle valve
Improved responsiveness through reduced air filling delays with valve lift air intake control
Reducing the catalytic activity hours / Exhaust temperature upward through delay of the ignition timing in an initial start
DC motor of the CVVL system is the device that can controls valve lift with the cam mechanism through rotating the eccentric shaft.
CVVL eccentric shaft and the motor system are as following shape.
CVVL position sensor measures the angle of rotation of the CVVL shaft using the two hall element and forwards this value to the engine control module (ECM). ECM controls the CVVL motor to move the valve lift position according to the driving condition.
[CVVL system operation mode]
CVVL system controls the intake valves to make the optimized valve lift and operation hours in each driving condition.
(1) Low speed / Low load | (2) Partial load |
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Improvement of idle combustion stability | Improvement of fuel efficiency |
(3) Low Speed / High Load | (4) High Speed / High Load |
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Prevention of intake back flow | Prevention of intake back flow Take advantage of the intake inertia |
