Variable valve lift is a technology which is increasingly used in automotive piston engines.
The swing angle of cam determines the degree of valve lift.
When the angle of the finger followers is narrow with respect to the roller member, valve lift is low.
As the angle increases, so does valve lift.
With electronic valve operation, it will be possible to control engine speed by regulating valve lift.
At part throttle, when less air and gas are needed, the valve lift would not be as great.
The valve lift must be at a maximum so as not to impede the flow into and out of the cylinder.
The Porsche patent used an oscillating cam to increase the valve lift and duration.
Higher valve lift can have the same effect as increased duration where valve overlap is less desirable.
Compared with the its N42 predecessor, the N45 does not have valvetronic variable valve lift.