The push to trim fuel consumption and emissions may prompt aircraft manufacturers to adopt some of the electric motor technologies used in hybrid cars and trucks. Honeywell Aerospace and Safran have teamed up to design a system that uses an auxiliary power unit (APU) to power planes during taxi operations.
The Electric Green Taxiing System demonstrated by Airbus in Paris, uses a small APU to power electric motors in the main landing gear so an aircraft can push back and taxi without engaging its main engines. In short haul operations, this can trim fuel consumption an average of 4%.
Honeywell APUs already provide power for ventilation, lighting, and starting engines for many aircraft. In a system set for production in 2016, the APU will drive electric motors placed on the two main wheel units. One wheel on each main gear employs an electric motor, reduction gearbox, and clutch assembly to drive the aircraft.
Dedicated power electronics and system controllers let pilots control an aircraft’s speed and direction. During development, the design team ran several tests before many of the components were ready.
“When you’re modifying the landing gear that much, you need to do a lot with the control circuitry,” said Mahendra Muli, New Business Development Director at dSpace. “Honeywell did a lot of modeling and simulation with hardware-in-the-loop, using our system onboard to control the drive motors.”
Currently, the wheel assemblies add around 300 lb each. Honeywell and Safran say that this weight can be reduced significantly over time. Some of these gains may come by leveraging the myriad efforts by semiconductor suppliers to help automakers develop electrified powertrains. Many semiconductor suppliers are adding hardware that makes it easier to drive the high-powered motors needed to move vehicles.