21 May 2002
New York City's transit authority has recognized BAE Systems Controls, supplier of a hybrid electric propulsion system used on city buses, sharing with the company an award the transit agency received from the U.S. Environmental Protection Agency. The EPA presented its Clean Air Excellence Award to MTA New York City Transit for "outstanding and innovative efforts in helping clean the nation's air" through its clean-fuel bus program.
"We are committed to establishing the cleanest bus fleet in the world and helping to reduce air pollution in New York City," said Lawrence Reuter, president of MTA New York City Transit. "Hybrid electric buses are an important part of that effort, and we are proud to share this award with BAE Systems in recognition of the company's efforts to develop this technology." BAE Systems developed and built the diesel-electric propulsion systems used in daily revenue service on a demonstration fleet of 10 buses and is producing similar systems for 325 buses currently on order.
"We are proud to play a role in developing technology that helps transit agencies meet their clean-air goals and helps to improve the quality of air in our cities," said Denyse LeFever, Director of Power & Drive Systems for BAE Systems Controls, producer of the HybriDrive propulsion system. "It's an honor to share in this award and be recognized by our customer and by the EPA.""
The EPA award cites both New York City Transit's efforts to reduce emissions and the fact that the transit authority's work has paved the way for commercialization of clean-air technologies that will benefit other cities.
Recent independent emissions tests on transit buses show that diesel-electric hybrid propulsion is much cleaner than modern diesel power and on par with compressed natural gas. The tests evaluated such emissions components as nitrogen oxides, particulate matter, greenhouse gases, and carbon monoxide. The hybrid buses also are far more efficient, delivering up to 50% more miles per gallon of fuel than the other technologies when operated in heavy urban traffic.
The test also measured fuel economy, with the hybrid bus delivering 5.3 miles per gallon compared to 3.5 mpg for diesel and 3.1 equivalent mpg for CNG. (For details, visit http://baesystemscontrols.com/FactSheets/emissions.pdf
The HybriDrive propulsion system uses an AC induction motor to turn the vehicle's drive wheels. The diesel-driven generator supplies propulsion power to the electric motor and recharges the vehicle's battery pack. In addition to lower emissions and improved efficiency, the configuration also offers better acceleration, providing maximum torque at zero speed and delivering power directly to the drive axle, with no energy lost through a mechanical transmission.
Reduced vehicle maintenance offers even greater potential for cost savings. No transmission means no transmission maintenance - a major consideration on any stop-and-go vehicle - and brake wear is reduced through a "regenerative braking" system that uses the drive motor to slow the vehicle and generate additional electricity to charge the batteries.
