The University of Colorado recently completed an option agreement with Boulder-based Tigon EnerTec Inc. for CU technology enabling efficient management of hybrid engines in aircraft.

Conventional airplanes employ an internal combustion engine that is sized for the high-power requirements of takeoff and climbing. However, most of a typical flight is conducted at lower-power cruising speeds, during which time the larger engine is burning fuel inefficiently. Electric motors, on the other hand, are able to operate at high levels of efficiency over a broader range of power output, but energy storage problems preclude the use of all-electric power systems in airplanes.

A team led by Jean Koster in the aerospace engineering department at the University of Colorado at Boulder have developed a method for switching between an internal combustion engine (powered by conventional fuel or biofuels) and an electric motor (powered by batteries, photovoltaic cells, fuel cells or other alternative power sources). The ability to transition seamlessly between these two motors maximizes overall efficiency and minimizes fuel consumption, while still meeting the high-power needs of takeoff and climbing. The research group also has made a number of adjustments to the system, nicknamed HELIOS, to reduce the weight, complexity and cost of the hybrid engine.

"Being able to selectively choose from torque sources, or combine them for maximum power, without the use of a clutch, opens up a range of propulsion options that can be optimized around whatever the mission need might be," said Tigon CEO Les Makepeace. Tigon is working with aerospace and defense customers to investigate unmanned air vehicle applications; the company also is investigating general aviation, marine and ground transportation applications.

"This is an exciting time for the company," Makepeace said.

The HELIOS project is a recent graduate of the CU-Boulder Renewable and Sustainable Energy Institute (RASEI) Market Assessment Program.

"Tigon represents CU and RASEI's strong focus on developing market relevant technologies that have immediate and broad real world applications," said Trent Yang, director of entrepreneurship and business development at RASEI. "Our incubation program identified the original market opportunity and we look forward to working with and supporting Tigon as it successfully transitions our lab technology into the real world."

RASEI recently funded a $40,250 proof-of-concept investment that will allow Tigon to further develop the technology.