Fiat Multiair Technology Increases Power, Lowers Emissions

Fiat has announced a new technology that will make its engines more efficient. The new engine technology is called Multiair and it comes from the brains that brought you the common-rail injection system that shook up diesel technology.

Multiair engines use electrohydraulic valve actuation, rather than the more widely available electromechanical systems. The engine’s intake valves are operated by a conventional valve spring, but they can be overridden by the MultiAir pack. There is a piston attached to each intake valve through a hydraulic chamber; the chamber is controlled by a solenoid valve that determines whether intake is governed by the conventional camshaft or the electronics.

The solenoid valve is shut during max load conditions where the valves’ operation is dependant on the position of the mechanical camshaft. The camshaft is tuned for a long opening time and extra power. When the vehicle is in partial load conditions, MultiAir can tweak intake performance on each cylinder for more low-end torque.

Fiat claims the electromechanical variable valve lift systems used by Honda and Toyota struggle to offer individual cylinder control. The company says the electrohydraulic system is much more flexible.

The system can cut CO2 emissions by between 10% and 25% and it can reduce the emission of other pollutants by up to 60%. It can also increase performance by 10% and improve low RPM torque by up to 15%. Expect to the see the first application of Multiair on the Alfa Romeo Mito this fall. In the future, we may even see its introduction on Fiat’s diesel engines as a way to reduce NOx emissions.