Ford & UCLA Design Hybrids Powered by Air

Air hybrid technology currently in development could result in fuel savings as great as 64% during city driving and 12% during highway driving, says a study from the University of California, Los Angeles. A team led by Tsu-Chin Tsao, a UCLA mechanical and aerospace engineering professor, is collaborating with engineers from Ford to get the technology up and running. The system is similar to that of a hybrid-electric vehicle in that braking energy is harnessed and stored to assist the engine as needed during acceleration. The air hybrid system differs in that it does not require a second electric propulsion system, resulting in saved weight and manufacturing cost.

The engine uses a valvetrain with electrohydraulic actuators rather than a conventional camshaft, allowing for greater variability in valve operation. During operation, when a car is decelerating the engine functions as an air compressor, absorbing braking energy and storing it in an air tank in the form of compressed air. The engine is shut off when the vehicle stops but is started up again by the compressed air when the driver touches the throttle. The car then accelerates under air power until the compressed air is depleted and the engine switches back to combustion mode. Work is now being done to optimize the size of the air tank and possibly to adapt the technology to diesel engines.