Fiat’s Twin Air Engine

2011 Fiat 500 w/ the TwinAir engine – 58.8 mpgUS combined on the NEDC. Approximately 5% less than a much larger Prius.

The 85HP version of the engine makes its UK debut this month under the hood of Fiat’s iconic 500.

Weighing just 187 pounds, the engine has the lowest CO2 emissions of any quantity production gasoline engine. Its 85 HP makes the Fiat 500 TwinAir one of the most powerful A segment vehicles (Micro’s) on sale. And with its 107 lb-ft of torque at a relatively low 1900 RPM’s, it is said to be responsive and fun-to-drive.

The TwinAir offers the highest fuel economy of any gasoline powered engine at 58.8 mpgUS and 57.4 mpgUS combined on the NEDC for the manumatic and 5-speed MT respectively.

What is a TwinAir?

TwinAir was designed from a blank sheet of paper, and is the first engine to be devised from the outset to exploit MultiAir technology that relies on a new electro-hydraulic valve management system.

In addition, closing the intake valves early to maximize the air introduced into the cylinders, and constant air pressure upstream of the cylinders, leads to prompt accelerator responses and improved torque at low speeds.

Performance is further boosted by a new generation turbocharger that increases maximum torque as well as making it available at very low revs. It ensures the TwinAir engine is more flexible and responsive compared with normally aspirated units, yet it remains simple to manufacture and therefore strong and reliable too.

To ensure there are no compromises in TwinAir ownership, FPT has paid special attention to noise, vibration and harshness (NVH). In order to maintain the two-cylinder’s characteristic hum while banishing vibration, a balancing countershaft, running at the same speed as the crankshaft in needle roller bearings to reduce friction, has been used. This gives the engine the same smoothness and refinement as a four cylinder throughout the rev range.

As with other recent Fiat Group cars, the Fiat 500 TwinAir comes with Start/Stop as standard equipment. This temporarily cuts the engine when the car is stationary and in neutral. It then re-fires automatically when the clutch is pressed. As well as reducing fuel consumption it also makes the passenger compartment quieter.

The Fiat 500 TwinAir is competitively priced at $17,353 USD in its base configuration. In the near future, the 85HP engine will be joined by normally aspirated 65HP and turbocharged 105 HP versions of the two-cylinder family.

Eco assist add-on’s

There is a dashboard-mounted ECO button that enables the driver to choose a more economical car or one that’s more responsive. In Normal mode, the maximum available torque for optimum response is enabled.

Press the ECO button and maximum torque is cut by 74 lb-ft@2,000 RPM.

The Gear Shift Indicator (GSI) is another ‘driver assist’ designed to improve fuel consumption. This uses arrows on the dashboard to tell the driver the most efficient point to change gear. An up-change might be suggested to allow the engine to burn a leaner mixture, while changing down might make the best use of the available torque.

Early Conclusions

I have no idea if this tech will make it to the US or if we would want such a thing given the Prius offers all of this and more in a car almost twice the size as the Fiat 500. It will be interesting to see how it sells once it arrives but I would not suggest betting the farm on a Fiat/Chrysler success story based off the micro sized 500 with TwinAir.




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