[Dazzler]

Not to be outdone by Mazda, Hyundai introduces it's own new engine technology.

Hyundai guns for Mazda's Skyactiv-X with "world's first" CVVD engine - Car News | CarsGuide

[mickd]

Different.
Reducing compression by having intake open, thus making engine reciprocating mass easier to roll over and using less fuel.
Fuel must be injected at the last moment .

Holden V6&8's held valves open and cut fuel supply if I  remember correctly.