Assembly, Variable Valve Actuation: Description: Description
WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.
The primary component of variable valve actuation is the variable valve actuation module. The variable valve actuation module is bolted to the top of the camshaft bearing housing above the intake valves, next to the camshaft. The intake lobes on the camshaft operate hydraulic pumping elements instead of directly acting on the valves. The pumping elements provide high-pressure oil to open the intake valves. The relationship between the camshaft lobe and the intake valves is controlled by a solenoid operated hydraulic port. By varying the solenoid operation, the Powertrain Control Module (PCM) is able to control intake valve lift and duration.