How Can A Three-Cylinder Engine Produce 600 Horsepower?

Three-cylinder engines are making quite big waves these days, but that wasn't always the case. They have however become such a big deal due in part to the fact that a three-cylinder engine is now capable of producing 600 horsepower. 

Three-cylinder engines used to be frowned upon for their roughness and lack of power, usually associated with cute little Japanese Kei Cars, known for their itsy bitsy dimensions and fuel efficiency.

These days, however, thanks to development in turbocharging and out-of-the-box engineering, the three-cylinder engine has moved ahead by leaps and bounds, even so far as creating 300hp per litre as found in the Koenigsegg Gemera.  

How can a 2.0-litre three-cylinder engine create 600hp, you ask? Well, it's down to big bores, big strokes, lightweight yet strong parts, an ingenious sequential turbocharger setup and something called Freevalve.

Known as the Tiny Friendly Giant (TFG), the 2.0-litre three-cylinder turbocharged engine in the Gemera was specifically created for the car. While the big bores and big strokes gave it a high revving character, the engine owes most of its brute power to the Freevalve technology and patent-pending two-stage turbo system.

The engine is the first in the world to use Freevalve technology that allows infinitely variable valve timing – basically offering total control over how much air the engine is breathing in and in turn how efficient or powerful it is. The technology has a huge range of applications, even if taken to the mass market and can transform relatively simple engines into incredibly potent powerplants. 

Koenigsegg says no other variable valve actuation system offers this level of control and reliability, which is why they were also able to create a patent-pending sequential turbo setup for the engine. 

Quite simply, one turbo is connected to three exhaust valves – one from each cylinder. The second turbo is connected to the other three exhaust valves. During low rpm and part to high load, all exhaust gasses are pushed to only one turbo, by only opening one exhaust valve per cylinder – thereby doubling the exhaust gases to that turbine. When adequate boost is reached, the second exhaust valve is opened to start the second turbo.

Combined together, the result is a three-cylinder two-litre engine that gives 400 Nm of torque from 1700 rpm with max torque of 600 Nm. These never-before-achieved numbers in an engine of this size make the TFG the most powerful engine per cylinder and volume to date, putting it light years ahead of any other production three-cylinder engine today.

According to an interview between road and track and Koenigsegg, despite the turbocharging making the TFG a potent engine, "in theory, a naturally aspirated TFG could make 280 horsepower", which is impressive in itself. 

In total, the Gemera achieves 1700 hp and 3500-ish Nm of torque when it combines the TFG with a hybrid setup that packs three electric motors. 

It’s a little crazy, isn’t it? They look like normal performance numbers with an extra “0” tacked on the end – but a Koenigsegg isn't a Koenigsegg without its wow factor!