Detroit Free Press: http://www.freep.com/article/20081026/BUSINESS01/810260378/1014/rss13Enlarge Photo
Fiat used the Geneva Motor Show to announce a brand new realm in the land of valve actuation, control, and timing. The technology, dubbed MultiAir, manipulates high-pressure hydraulic fluid to override the engine's valve springs during various operating conditions, resulting in significantly more power, more torque, better drivability, and cleaner emissions across the board.
Fiat claim a remarkable 25 percent decrease in fuel consumption, a 10 percent increase in horsepower, and a 15 percent improvement in low-end torque (the last crucial for small engines). Also significant are emissions improvements; Fiat claim up to a 40 percent reduction in unburned hydrocarbons and a huge 60 percent cut in NOx. The latter is huge news for diesel engines, as NOx is diesel's biggest hurdle in meeting emissions standards (and the reason for urea injection and complicated catalysts).
Fiat MultiAirEnlarge Photo
Variable-valve timing is nothing new; Honda's VTEC debuted on the first-generation NSX in the 1990s. But that system, like most others still in use today, is a mechanically operated system that Fiat claims has notable limitations when compared with the MultiAir's hydraulically-actuated system. MultiAir controls each cylinder's intake valves independently, further increasing the benefits already provided by variable-valve timing.
Further, by allowing the intake valves to act as little throttles that regulate the amount of air entering each cylinder, the main throttle valve can be completely eliminated (and a ten percent energy savings realized). Again, Fiat is not the first to do this; BMW introduced the technology in its last-generation 7-series and called it Valvetronic. Nissan does the same on its 3.7-liter V-6 as fitted in the 370Z, calling it VVEL (Variable Valve Event and Lift). But Fiat's MultiAir manages intake valve throttling with simpler, sturdier hydraulic actuation that can be tailored individually for each cylinder.
Fiat says that MultiAir is applicable to all internal combustion engines, regardless of the fuel used. Their first production plans for MultiAir are on the MiTo, where 1.0- and 1.4-liter four-cylinders will act like bigger engines while delivering stellar economy. Having extracted more power and efficiency than ever from the old internal combustion engine, they're even developing a 900cc (that's 0.9-liter!) two-cylinder for efficiency in extremis. Could this new technology mark the eventual return of misers like the Citroen 2CV, this time with more power than a moped?