CATA Hybrids

CATA is introducing three new hybrid buses to its fleet this month (read the press release). The buses were built in Minnesota by New Flyer Industries, Inc., and have General Motors Allison hybrid technology, which blends diesel and electric power to provide a more environmentally friendly transit vehicle.

What is hybrid technology?

It’s a blend of two power sources to reduce emissions. In this case, the blend of electric and diesel reduces the use of the diesel engine. It’s a bridge between conventional internal combustion engines and the ideal of zero-emission propulsion systems.

How does it work?

From about zero to 25 miles per hour, the bus uses only electric power, depending on driving conditions. Diesel power blends with the electric power from 26 mph up to about 40 mph. At greater speeds, diesel power is the sole propulsion system.

• Up to 40% of the energy used in acceleration comes from energy saved through regenerative braking. Energy that would have been lost when decelerating or stopping the bus is stored in batteries located in a storage system on top of the bus.
• Hybrid buses are ideal for a variety of driving conditions, but they really shine in stop-and-go city traffic because the diesel engine usually doesn’t kick in until the bus exceeds 25 miles an hour. (Diesel power may be needed for uphill acceleration.) Emissions are significantly reduced because operating a diesel engine at lower speeds has the potential to produce the most emissions.   

What are the benefits?

Cleaner air. Hybrids reduce emissions up to 90% compared to conventional diesel buses currently on the road today. CATA buses operate on ultra-low sulfur diesel fuel, which produce cleaner emissions than conventional diesel buses. The new hybrids will significantly reduce those already lower emissions levels. In recent years, the Lansing tri-county area has been classified non-attainment for ground-level ozone by the U.S. Environmental Protection Agency. The most recent air quality monitoring data demonstrates that this area is now meeting the federal 8-hour ozone standard. Hybrids will help keep our air clean.

Noise reduction. Noise level is significantly reduced, approaching that of a personal vehicle. Passengers enjoy a quieter ride, and the hybrid buses create less external sound as they travel through populated areas.

• Fuel efficiency. This hybrid system increases fuel efficiency 20% to 40%.
• Fewer delays. More responsive acceleration allows hybrid buses to keep up with the flow of traffic.
• Smoother performance. Passengers and bus operators will notice a smoother ride because hybrids do not use a mechanical shifting mechanism during acceleration.
• Maintenance savings. Hybrids take less time to maintain, and the buses require fewer part replacements. They have extended brake life, there is no transmission to maintain, and there is less wear on the suspension.

Where else are hybrid buses being used?

There are 478 GM hybrid-powered buses operating in the United States and Canada. King County Metro, which serves Seattle, was the first to buy GM hybrid-powered buses, in 2004, and now has more than 200 hybrid buses in its fleet.

Hybrid Bus Specifications

• Make and Model: New Flyer low-floor parallel hybrid diesel-electric bus
• Overall length: 40 feet
• Width: 8.5 feet
• Height: 11 feet – about a foot higher than other buses because of the roof-mounted energy storage system.
• Seating capacity: 37
• Accessibility: Flip-out ramp at front door
• Fuel capacity: 125 US gallons
• Engine: Cummins ISL; 280 HP Diesel
• Electrical system: Vansco Multiplex System
• Energy storage supplier: General Motors Allison – NiMH (nickel metal hydride batteries stored in the roof unit)

Procurement

Each 40-foot hybrid bus costs $508,900. Federal grants paid 80% of the $1,526,700 cost for the three buses. The Michigan Department of Transportation (MDOT) provided the remaining 20% in matching funds. Congressman Mike Rogers and Senators Debbie Stabenow and Carl Levin were instrumental in securing the federal funding for the buses.