Thursday, July 8, 2010

Fiat drops down a size

The idea of ‘turbo-downsizing’ took another step forward today with the unveiling of a new family of twin-cylinder 900cc engines from Fiat. The turbocharged TwinAir range, set to debut in the Fiat 500 next September, promises performance equal to that of a conventional 1.4-litre unit, despite 30% reductions in fuel consumption and CO2 emissions. It does so by combining the current trend for small capacity turbocharged engines with Fiat’s clever MultiAir valve control system.

The result is 85bhp from a small, lightweight engine that returns 57mpg and emits just 92g/km of CO2. It’s perhaps the purest application of the turbo-downsizing theory so far, having only two cylinders and displacing less than a litre, and shows the technology has truly come of age.

The TwinAir-equipped Fiat 500 is good for 107mph and dispatches the 0-60mph sprint in 11 seconds. This comfortably trumps the current base spec 1.2-litre model and comes within a whisker of the 1.4, but what’s perhaps more impressive is that it produces 145Nm of torque from just 1,750rpm in standard mode. A special ‘city mode’ reduces this to 100Nm, softens up the throttle response and re-programs the robotized manual gearbox (where used) to maximise fuel economy around town. Additionally, all cars come with a gearshift indicator light to prompt you when best to change gear and a stop-start system to cut the engine in traffic.

The Fiat press release also hints at bigger things to come. The TwinAir engine’s compact dimensions make it particularly easy, it says, to package an auxiliary power source such as an electric motor next to it. Also, it’s said a version of the TwinAir engine featuring methane injection, running in parallel with the usual petrol supply, will soon be available. According to Fiat this should reduce CO2 emissions to the point where they’re hard to better with a conventional internal combustion engine. That’s a bold claim, but there again a sub 1-litre turbocharged direct injection twin-cylinder hybrid (and breathe...) is pretty much the specified goal of current small car powertrain thinking.

(Photo for illustration only. Source: Newspress)

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