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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.


John Norris

Capacity is 900cc (0.9 litre).


"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."

If this is true, the engine should be incredibly inexpensive without the dozens of valve-train precision machined parts.


On reflection (and cut-away), it appears to have valves (4?).


Fiat/Chrysler could be "first to be second" in the range extender market. If PHEVs and range extended EVs become popular, they might offer one at a lower price with better economy.


I am curious about the effect of combining/integrating some of these astonishing technologies. For example this motor with Getrag's "Boosted Range Extender" posted a couple of days ago; which is set up for a 2 cylinder engine.
85 HP is plenty of power for a small car weighing 2500 lbs.


An engine this small should be able to be mounted just above and infront of the rear axle of a vehicle leaving the bonnet of the car free to house batteries and an electric motor driving the front wheels.

fred schumacher

I would hope Chrysler would make this engine available in the U.S. What we don't need are more cookie cutter 4-cyl engines. Two cylinders would announce that Chrysler is looking toward the future, not the past.

There is a parallel for Chrysler. When the new "old look" pickup came out in 1993, the auto press said it was a huge risk for Chrysler. In reality, it was a no brainer. Chrysler was only selling 50,000 trucks per year. It was virtually out of the truck business. The new design failing would not change that reality. Instead it succeeded beyond Chrysler's wildest dreams.

There's a market out there for an inexpensive, fuel efficient commuter-car/light-delivery vehicle. A high-roofed plain Jane station wagon version of the Fiat 500 with the two-cylinder and selling for under $12,000 would be a big hit from the urban megalopolises, with their limited parking, to the wide open spaces of the American West, where anywhere is far away.

For a range-booster engine for a serial hybrid, 85 hp is too much. I would work on a single-cylinder, dry sump, non-turbo, canted, true-Atkinson cycle Multi-air engine genset in a self-contained, sound-deadened box. Combined with hub motors, such a system could be low cost and allow for high passenger volume efficiency on a small external envelope.


Fiat may be widening the playing field with high performance 2-cyls units suitable for many PHEVs and small ICE vehicles.

An AWD small Jeep Patriot PHEV with this 2-cyls to drive the genset range extender could help Chrysler to regain market share.


If you can make 80 hp at 6000 rpm, I would want it to make 20 hp at 1500 rpm. I do not want an engine revving away in a genset.

Nick Lyons

This engine is overly-complex to be used as part of a genset/range extender. You don't need the fancy Multiair valve train if you're going to run at constant speed and load.


It may be like Chevy using the 1.4L Cruze engine in the Volt, they plan to make a lot of them so they use it elsewhere. Which brings me to Fisker using the Pontiac/Saturn 2.0L turbo. If GM continues to make it for other vehicles then fine, if not then that is a problem.


Add a pancake motor and give it a manual gearbox and the 500 should get 50mpg


Yes, replace the flywheel with a motor much like the Honda IMA. Very simple and straight forward, it works and will give good mileage. It can also be sold at a price people can afford. Look at the VW Beetle and the Datsun pickups.

Roger Pham

The beauty of this thing is that it has only two cylinders, thus halving the number of valves,cams, injectors, spark plug, coils, pistons, rings, cylinders etc. and the crankshaft and cam shafts are only 1/2 as long, so that they can afford to equip it with the latest Multi-Air technology to make it even more efficient.

85 hp is not too much, because when one modifies the engine to run on Atkinson cycle, the 85 hp will be reduced to about 60-65 hp.


"replace the flywheel with a motor much like the Honda IMA. Very simple and straight forward..."

Not that simple at all. It's a patent minefield. Honda has tens of patents for various aspects og IMA layout. PSA Peugeot has 2-3 that cover various issues of their implementation - IMA style.

Peugeot may have selected "thru the road" hybrid layout in order to avoid being sued for patent infringement.
Their system is obviously expensive one, assumes 4WD, and they don't make 4WD/AWD cars (use Mitsu designs for SUVs).
Some other (Ford, Nissan) licenced from Toyota the most advanced hybrid system.

Henry Gibson

At least two electric boosted turbo-superchargers have been built, and one should be built for this engine. Such an engine can be built to have torque at zero RPMs. I wanted to hold out for a single piston and have the computer simulate two, four, eight or sixteen as it does gearshifting in the headline concept electric car. ..HG..

Henry Gibson

This engine is very high class engineering. ..HG..

fred schumacher

Even a genset engine needs some throttle control, which requires controlling air inflow. The beauty of Multiair is that it eliminates the throttle plate and its pumping losses. That's where the efficiency gains come from.


There may be some savings by reducing the component count (pistons, connecting rods, valves) but there is no escaping the added cost of a turbocharger and Multiair components itself. This IS very high class engineering, as HG said, but I have a hard time imagining that the added costs of the technology won't outweigh the savings on reduced component count. The parts that are getting replaced are older-technology parts that are made in large numbers. The turbo and Multiair valve actuation components are fairly small-volume, cutting edge technology parts that are a long way from being commoditized.



That brings me back to my point on patent reform. It is to recover development costs and not a monopoly license to restrict innovation.

fred schumacher

Multiair and a turbo add complexity, but of an order of magnitude less than the complexity of a fuel cell, and they involve well-known manufacturing methodologies. If a marine diesel is already able to match the thermal efficiency of a fuel cell, then there is room for efficiency improvements in spark ignition.

One of the advantage of an IC is its high power/density ratio. A two-cylinder allows for for more efficient packaging and reduction in the overall external volume and mass of a vehicle.


One advantage to a DFMC range extender is no combustion at all. No particulates, no unburned hydrocarbons, no NOX, no smog nor ozone. If they can get a large, cost effective and efficient DMFC, people may wonder why we use engines at all.

Thomas Pedersen

This engine looks very well suited as a range extender for a c or d class hybrid vehicle. As SJC said, it will almost never run at rated power but around 2000 rpms.

This engine made me think about the serial hybrid concept and its pros and cons. The pros are, the engine runs at optimum rpm and torque for its job at any given time decoupled from the load changes required by the road (and driver). The cons are; separate generator, efficiency losses by going mechanical -> electrical -> mechanical during highway cruising.

Here is my proposal:
Run the car as a parallel hybrid but with the engine disengaged during city traffic. I assume a car with battery capability for comfortable city driving and acceleration. A car with 30 mile battery range would only need to use the range extender on highways where the speed is pretty constant anyway. Have this engine coupled to the drivetrain at a gearing ratio of, say 25-30 mph @ 1000 rpm. This way, the engine will run between 1700-3000 rpm, its sweet spot, 95%+ of the time. And it does not even have to respond to changes in torque requirements because this is handled by the motor/generator! Once the speed of the vehicle drops below 1300 rpm, the engine is disengaged and shut off.

An engine as this should be able to propel an aerodynamic c/d class vehicle at 75-90 mph without breaking the inefficient 3000 rpm barrier. A parallel hybrid like this would be simpler and cheaper to build, I would say.

Parallel hybrids just got back in the game in my mind!

Stan Peterson

I remain to be convinced that this two cylinder engine will prove to be the panacea that all the greens here posit. I have plenty of experience listening to the 900 cc twin Harley-Davidson, engine. I don't need that in an 'A segment' car.

I remain to be convinced that this twin cylinder will be as smooth as a 4 cylinder, but probably better than an unbalanced triple 3 cylinder.

It should offer an improvement only for "A segment" vehicles that historically have not been offered here by any manufacturer domestic or foreign. Even though they all make micro cars overseas. It is mostly sold in under-developed nations only getting motorized transportation for the first time, or as Kei City cars.

The "success" of the Smart will be duplicated by the Spark and any other micro car introduced into America, I think. Some cars are just too small; and an answer to a question that electricity is making mute, in any case.

As far as a gen set driver, I expect that the power developed at 6000 rpm will prove way too noisy to be suitable. And quite frankly it is wholly irrelevant.

For the tiny amount of time it runs, you could use a blown 6000cc Corvette engine, as the gen-set driver, and it would not alter the overall mileage obtained significantly.

Here I agree with GM's choice of its Family 0, 1.4 liter gen-set driver, instead of its available 1.2 liter version, or its 3 cylinder 1.0 liter version of that Family 0 engines. Both alternatives might have worked but would require them to run at high rpm, and the 1.0 liter would have to run near red line, all the time.

fred schumacher

This engine would be nothing like a Harley Davidson twin with its loping 245 degree timing pulses. And it would take up much less room and weigh less than existing genset engines. This allows for more efficient packaging. It means rethinking automotive morphology to tap into synergistic effects. After all, most of the time, the car is only moving one person down the road. It doesn't require 4,000 pounds to do that.

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