Cylinder deactivation has been around for a while. After its initial experiments during WWII, Cadillac was the first to introduce the technology in its L62 engine . Since then the technology has been widely used but has been much more common in larger engines produced by prestige marques such as Mercedes and Bentley.
VW has broken the trend with the VW Passat BlueMotion Concept. It’s 1.4 litre (TSI) turbo charged power plant will be capable of halving its cylinder usage from 4 down to 2. The result being that the Passat will be capable of an impressive 42MPG highway (50MPG). That’s a mighty impressive feat considering its size and has a petrol engine with 150BHP under the “hood”.
In comparison the UK spec Passat 2.0 TDI BlueMotion returns a claimed 61.4MPG but produces 12BHP less than the concept car. The news is likely to be of interest to those motorists wanting the refinement of modern turbo charged engines but have had to sacrifice fuel efficiency.
Even if the Passat BlueMotion Concept doesn’t hit the showrooms state side, its very likely that the technologies will. Here in the UK we are already enjoying the benefits of the technology aboard the Polo Blue GT. The same engine technology powers the super mini to 60 in less than 8 seconds while returning a staggering 61MPG and emitting just 107g/km of CO2.
Learn more about VW’s cylinder deactivation technology here http://www.volkswagen.co.uk/technology/petrol/active-cylinder-technology-act
 Thanks to http://en.wikipedia.org/wiki/Variable_displacement