Schaeffler Technologies AG

UniAir Fully Variable Valve Lift System

Globally, regulation and market demand are pressuring OEMs to provide vehicles with improved fuel efficiency and reduced emissions. Proposed U.S. fleet wide average fuel economy for 2025 is a 100% increase over the 2011. During this same period, proposed CO2 emission limits are expected to decrease 50%.

Although electric hybrids and powertrain electrification will play a more significant role in meeting future vehicle designs, the internal combustion engine is still expected to dominate the powertrain landscape for years to come. Therefore improvements in internal combustion engine efficiency and performance are required.

Most modern internal combustion engines employ a fixed valvetrain that allows for only a single, discreet valve lift. As a result of the fixed valve lift, manufacturers must compromise an engine's air intake performance across the entire operating range. Schaeffer's UniAir system provides improved engine efficiency by optimizing the fresh air charge entering into the combustion chamber. With UniAir, a cam-actuated valvetrain component displaces oil in a gallery that pushes against the engine valve causing it to open. The combination of electrical controlled solenoid and hydraulics provide unparalleled flexibility in varying engine valve motion.

Schaeffler's UniAir technology is a key component of Fiat's MultiAir system, which debuted in 2009 and provides up to 10% improvement in fuel efficiency and CO2 reduction.