Fiat to Preview Turbo Two-Cylinder Twin-Air at Geneva Show; Natural Gas and Hybrid Applications to Come
|The new two-cylinder Twin-Air. Click to enlarge.|
Among its displays at the upcoming Geneva Motor Show, Fiat will preview its new turbocharged two-cylinder 85 hp (63 kW) Twin-Air engine fitted aboard a 500, the first Fiat model on which it will be introduced next September. CO2 output from the engine is projected to be 95 g/km.
Progenitor of new family of two-cylinder engines—to range in output from 65-105 hp—made by Fiat Powertrain Technologies (FPT), the engine implements a Multiair system combined with specific fluid dynamics optimized for the best fuel efficiency.
The new Twin-Air engine is an example of downsizing: combining a small displacement engine with a next-generation turbocharger to provide performance comparable to—or better than—that of a larger engine but with less fuel consumption and lower emissions. The turbo significantly increases the maximum torque, making it available at a very low rpm.
Applied in the 500, the new turbo two-cylinder 85 HP engine consumes down to 15% less fuel and has 25% more performance than the 1.2 8v, while fuel consumption drops 30% with respect to the 1.4 16v with comparable performance and the same driving pleasure.
With respect to a four-cylinder of equal performance and medium displacement, the new engine is significantly shorter (-23%) and lighter (-10%), opening the way to interesting further developments, such as natural gas fuel feed or hybrid technology combinations.
In particular, a natural gas version of the Twin-Air will be available soon providing a further CO2 emission reduction; this is possible by adopting a pair of special injectors in addition to the gasoline injectors on the intake manifold rails. Fiat also notes that because of its small size, the Twin-Air is well suited to be applied in a hybrid system.
The two-cylinder implements FPT’s Multiair technology, introduced on FIRE engines last year for the first time. (Earlier post.) The core of Multiair is a new electro-hydraulic valve management system that reduces fuel consumption by controlling air directly via the inlet valves without using the throttle. Multiair reduces polluting emissions with improved combustion control and also considerably improves performance by boosting driveability with respect to a traditional gasoline engine of equal displacement.
The basic two-cylinder architecture, combined with the low friction of internal parts, ranks this engine best in the friction class in the world, according to Fiat. Furthermore, computer simulations were used to identify the best possible standard displacement in terms of thermodynamic efficiency, and the best fluid dynamic configuration to optimize and get the best out of the Multiair system.
FPT placed special attention on the NVH (Noise, vibration, and harshness) aspect to ensure vibration performance at least equivalent to that of a four-cylinder, with equal performance but with a characteristic sound. For this purpose, a balancing countershaft was used to maintain optimal vibration levels in all operating conditions of the engine, from the idling speed to top power.