Oak Ridge National Laboratory, Mich.-based companies Autokinetics and Fisher Coachworks, and funding from the Department of Energy (DOE) have contributed to the creation of a lightweight urban transit bus with double the fuel efficiency of conventional hybrid buses.

This 40-foot bus features a high-strength stainless steel body and chassis and a hybrid power system that drives the bus primarily with stored electrical energy. This approach reverses the paradigm of conventional parallel hybrid designs that use electric energy only to supplement the acceleration and torque requirements of a diesel engine.

Advantages include improved vehicle safety for passengers, lower cost, reduced noise and improved ride dynamics.

At the heart of the bus is a chassis made of Nitronic 30, a nitrogen-strengthened stainless steel that is stronger and stiffer than conventional steel. These attributes translate into less material required for a chassis, resulting in reduced weight.

Additional advantages of Nitronic 30 include excellent mechanical properties at sub-zero and elevated temperatures along with low-temperature impact resistance and superb resistance to high-temperature oxidation.

Fisher Coach Works licensed the technology, has produced a prototype and plans full commercialization.

Specific contributions from ORNL included computer crash studies and infrared thermal imaging to evaluate the quality of some of the initial laser welds in the structure.

Funding for this project was provided by DOE’s Office of FreedomCAR and Vehicle Technologies Program.

Deliveries of the bus are expected to begin in 2009.