Hybrid propulsion manufacturer Permo-Drive Technologies has developed a compact version of its hybrid hydraulic drive system for medium-duty trucks, promising to improve fuel economy of these commercial vehicles by 30% or more.

Ballina, Australia-based Permo-Drive said its new design is 300 lbs. lighter and significantly smaller than the prototype systems first developed by the company last year.

VP Paul Chandler said that Permo-Drive's new system is "ideally suited for Class 6 to 7 trucks and represents an important, evolutionary step in the development of hybrid hydraulic drive technology."

Installed on a medium-duty truck, the system acts like a second 340-horsepower engine, Chandler said.