FREEVALVE VS. FIAT’S MULTIAIR

I would be curious to know how the Free‐ valve pneumatic actuators work in the Koenigsegg Gemera. Is it anything like the Fiat Multiair system and is the technology used for cylinder-deactivation?

Fiat’s Multiair engine technology is linked to the conventional camshaft driving the intake valves. It consists of electronic actuators – one per intake valve – which alter the valve lift (and timing to a degree) by moving the position of a rolling element between the valve and the cam‐ shaft. This allows optimum control of the fresh air charge to suit every speed and load condition and can replace the need of a throttle valve in the intake. Multiair is not a cylinder-deactiva‐ tion technology as the exhaust valves remain operational via a conventional camshaft.

The Freevalve-technology engine is termed “camless” as there are no physical camshafts. Each valve, intake and exhaust is individually controlled by an actuator per valve. This actu‐ ator is controlled by the engine-control unit and the result is almost infinite lift and timing com‐ binations. The actuator itself is part of the pro‐ prietary information of Koenigsegg but it is known to employ pneumatics (air pressure) to open and close the valve; and hydraulic pressure moves a physical stop to limit valve lift and keep the valve stable during opening. The Free‐ valve technology can be used for cylinder-deac‐ tivation as all the valves can be kept closed when the cylinder is not in use.

The advantage of both technologies is that the airflow to and from (Freevalve only) the combustion chamber can be precisely controlled using air dynamics to increase effi‐ ciency and power while lowering emissions. So, why do we not see this technology in every engine? The main reasons are cost, complexity and reliability. The conventional camshaft has proven itself over the years and in the face of the electric powertrains, it may just survive to the end.