[Rokeby]

Fiat has electrohydraulic valve actuation as the centerpiece in its new
MultiAir system:

"At the outset, world-wide research efforts were focused on the
electromagnetic actuation concept, by which valve opening and closing is
obtained by alternatively energizing upper and lower magnets with an
armature connected to the valve. This actuating principle had the intrinsic
appeal of maximum flexibility and dynamic response in valve control, but
despite a decade of significant development efforts, the main drawbacks of
the concept – it being intrinsically not fail-safe and its high energy
absorption – could not be fully overcome.

"At this point most automotive companies fell back on the development of
the simpler, robust and well-known electromechanical concepts, based on
valve lift variation through dedicated mechanisms, usually combined with
camshaft phasers to allow control of both valve lift and phase.

"The main limitation of these systems is low flexibility in valve opening
schedules and a much lower dynamic response; for example, all the
cylinders of an engine bank are actuated simultaneously, thereby excluding
any cylinder selective actions. Many similar electromechanical valve control
systems were subsequently introduced over the past decade.

"In the mid ’90s, Fiat Group research efforts switched to electro-hydraulic
actuation, leveraging on the know-how gained during its Common Rail
development. The goal was to reach the desired flexibility of valve opening
schedule air mass control on a cylinder-by-cylinder and stroke-by-stroke
basis.

"The electro-hydraulic variable valve actuation technology developed by Fiat
was selected for its relative simplicity, low power requirements, intrinsic
fail-safe nature and low cost potential."

http://www.youtube.com/watch?v=5IrPcmMHqHE

And this.