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Green school bus

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Though you might think of aerodynamic little econocars when the term “hybrid” is mentioned, an Arkansas company will soon be bringing a much bigger gas/electric vehicle to the market — and to a bus stop near you.

IC Corporation (formerly Ward Bus Company) in Conway has won the contract to produce the nation’s first hybrid-powered school buses. One of the first off the assembly line is scheduled to be in service with the Little Rock School District as early as next spring.

Produced for a consortium formed by 11 school districts and Advanced Energy, a Raleigh, N.C.-based non-profit group founded by the area’s five largest electric utilities, the initial run of 19 school buses will feature a bank of nickel-hydride batteries mounted on the frame rail, and an 80-kilowatt electric motor added behind the transmission. During service, the bus’s standard diesel engine will run at a constant, low RPM to operate accessories such as power steering and brakes. Once the batteries are drained to 20 percent, the diesel engine will cycle up to a higher speed to keep the batteries at that level. A “regenerative braking” system, which produces electricity every time the bus is slowed or stopped, will also help keep the batteries charged. Employing what is called a “charge depleting” hybrid system, the bus will have to be plugged in while it is off duty to bring the batteries up to 100 percent charge.

Engineers with IC Corp. say the system will double the miles per gallon of the average school bus for at least the first 44 miles, with a 30 to 50 percent improvement in fuel efficiency after that.

Advanced Energy issued a call for hybrid bus proposals from school bus manufacturers in June. On July 25, the company announced that IC Corporation, the country’s largest manufacturer of school buses, had won the contract. The buses will be built in cooperation with Enova Systems, a manufacturer of gas/electric hybrid power trains and components, based in Torrance, Calif.

Randall Ray is manager of bus platform marketing for IC Corporation. He said the plug-in hybrid system that will be used in the buses is the next big thing. “Plug-in hybrid is the gateway,” Ray said. “It’s going to get us to the future.”

Because of the use of regenerative braking, Ray said the plug-in hybrid system is ideal for commercial truck applications where drivers have to make many stops and starts: buses, delivery trucks, garbage haulers and vans. The system also has military applications, Ray said, because of quieter operation and better fuel economy.

“That’s much less logistics [the military] has to deal with,” Ray said. “That’s one fewer barrel of fuel they have to bring into a forward location.”

For now, Ray said, the biggest hurdle to making hybrid buses more widespread is the cost. The hybrid package — electric motor, batteries, a control box, and an additional radiator for the liquid-cooled system — will almost double the price of a standard school bus, to about $215,000. Ray said the key to bringing down the cost is mass production.

The goal, he said, is to get the technology cheap enough that the money school districts save on fuel will balance out with the additional cost of the hybrid system within three to five years of purchasing the bus.

Currently, one prototype is touring industry trade shows throughout the country, and another is undergoing cold-weather, real world testing in New York state. Ray said the production of the initial run of 19 buses should begin in Conway in January, with Little Rock’s bus scheduled for delivery in late March or early April. Other hybrid buses will go to districts in North Carolina, South Carolina, New York, Florida, California, Washington, Iowa and Texas. The result could be a greener trip to school for the kids of the future, and fewer clouds of diesel smoke to inhale during your morning commute.

“The plug-in thing is happening,” Ray said. “We’ve got to make it happen and get it cost effective so the industry can embrace it. Not just school buses but the entire medium and heavy industry.”

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