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From MultiAir to FireFly: a new era of engine technology

By Luca de Ruiter · · 5 min read

For more than a decade, Fiat’s small petrol engines were built around two ideas: the FIRE engine family and MultiAir valve control. The FireFly engines, officially the Global Small Engine (GSE), replaced the FIRE and brought MultiAir into its third generation. Here is how the family is put together and where MultiAir fits in.

Where it starts: MultiAir

MultiAir arrived in 2009 on the 1.4 FIRE engine in the Alfa Romeo MiTo. Instead of an intake camshaft acting directly on the intake valves, an extra cam lobe pressurises engine oil, and a solenoid valve decides how much of that oil pressure reaches each cylinder’s intake valves. The engine can vary intake valve lift and timing cylinder by cylinder and stroke by stroke, and controls its air charge at the valves instead of mainly with the throttle.

The 1.4 MultiAir turbo won Best New Engine at the International Engine of the Year awards in 2010. If you want the full mechanism, read how MultiAir works.

The FireFly family: one cylinder, two engines

The GSE was designed as a modular family. Every version uses the same cylinder dimensions, 70 mm bore and 86.5 mm stroke, roughly 333 cc per cylinder:

VersionCylindersDisplacement
1.03999 cc
1.341,332 cc

The three- and four-cylinder engines share pistons, rings and connecting rods. For the manufacturer that means cheaper production. For owners and parts suppliers it means fewer different parts across the range.

2016: naturally aspirated, in Brazil

The first FireFly engines went into production at Fiat’s engine plant in Betim, Brazil, and debuted in the 2017 Fiat Uno, announced in September 2016. They were simple, robust engines for the South American market:

These first versions do not use MultiAir. They went on to power the Uno, Mobi and Argo, and later served as the base for the turbocharged T200 and T270 flex-fuel engines used in South American Fiats such as the Pulse and Fastback.

2018: FireFly Turbo and MultiAir III

The version that matters for Europe and North America is the FireFly Turbo, built at FCA’s plant in Bielsko-Biała, Poland. It arrived in 2018 in the facelifted Jeep Renegade and the updated Fiat 500X:

Compared with the Brazilian engines, the turbo versions have four valves per cylinder, direct injection, a compact turbocharger with an electronically controlled wastegate, a petrol particulate filter, and MultiAir III. The all-aluminium block was developed with FCA’s casting subsidiary Teksid; the three-cylinder weighs 93 kg. In Jeeps the engines were badged simply 1.0 MultiAir and 1.3 MultiAir.

FCA claimed the new engines were up to 20% more efficient than the ones they replaced, and in June 2019 the Bielsko-Biała plant built its 100,000th FireFly Turbo.

What MultiAir III does differently

The principle is the same as the original system: oil pressure, controlled by a solenoid, opens the intake valves. MultiAir III adds dedicated intake and exhaust cam profiles and uses the valve control in two specific ways:

In other words, MultiAir moved from being mainly a replacement for the throttle to being a tool for managing combustion on a small, highly boosted engine.

FireFly and hybrids

The modular design made the GSE the base for most of the group’s electrified small petrol engines:

What to watch for

The FireFly engines are still relatively young, but some patterns are already reported:

When buying a used FireFly-engined car, check the service history and whether the specified oil was used. And when parts are needed for the valve control or the turbo, original parts are the safe choice: like every MultiAir engine, the FireFly depends on tight tolerances and clean, correct oil.

Sources

#FireFly#MultiAir#Fiat#Jeep#Alfa Romeo