How Koenigsegg’s 3-cylinder engine makes 600 horsepower
The Koenigsegg Gemera is a four-seat hypercar that can do 0-62 mph in a claimed 1.9 seconds, but perhaps the most remarkable thing about this Swedish rocket ship is its 2.0-liter twin-turbocharged inline-3, which makes a staggering 600 horsepower (plus 443 pound-feet of torque).
Jason Fenske at Engineering Explained has the details on how Koenigsegg extracted so much power from such a small engine. It starts with the cylinders. There may not be many of them, but they are pretty big. They’re actually larger than the cylinders in Koenigsegg’s 5.0-liter V8, Fenske noted.
Koenigsegg also dialed this engine up to 11. Its twin turbos produce a lot of boost (29 psi) but, like a naturally aspirated engine, the 3-cylinder can also rev high. Redline is at 8,500 rpm. That means the pistons move extremely fast. The speed is about the same as that of current Formula One engines, according to Fenske.
The 3-cylinder engine also uses Koenigsegg’s cam-less FreeValve system. This allows greater control over valve operation, providing more opportunities to make power. The downsides are complexity, cost (you won’t be seeing FreeValve on a Ford Fiesta or Mini Cooper anytime soon), and the extra energy needed to drive the pneumatic actuators that open and close the valves.
FreeValve did make the complicated 3-cylinder twin-turbo setup work, though. Each cylinder has one set of exhaust valves for each turbo. FreeValve allows one of those valves to stay closed at lower rpm, meaning only one turbo is used. That allows the single turbo to spool up faster. At higher rpm, the second valve opens and exhaust gases are sent to both turbos.
Mounted behind the rear seats, the 3-cylinder engine works with two electric motors, for a total of 1,700 hp. Some of that power can be sent to the front wheels via a torque tube and clutch assembly, giving the Gemera all-wheel drive. A 16.6-kilowatt-hour battery pack provides the electricity, and allows for around 30 miles of electric driving, as measured on the European testing cycle.
Gemera production will be limited to 300 units at an unspecified price. That’s exclusive even compared to many other supercars, but will still make the Gemera the most prolific Koenigsegg to date.