Continuous Variable Valve Timing - Late Intake Valve Closing

Late Intake Valve Closing

The first variation of continuous variable valve timing involves holding the intake valve open slightly longer than a traditional engine. This results in the piston actually pushing air out of the cylinder and back into the intake manifold during the compression stroke. The air which is expelled fills the manifold with higher pressure, and on subsequent intake strokes the air which is taken in is at a higher pressure. Late intake valve closing has shown to reduce pumping losses by 40% during partial load conditions, as well as decreasing NO emissions by 24%. Peak engine torque showed only a 1% decline, and Hydrocarbon emissions were unchanged.