Diesel/electric hybrid bus maker takes RFTA for a ride | PostIndependent.com

Diesel/electric hybrid bus maker takes RFTA for a ride

Greg Masse

A quieter, cleaner and more fuel-efficient bus prototype developed by Allison Electric Drives toured the Roaring Fork Valley Thursday.

Less noise, reduced emissions and more miles per gallon make Allison’s hybrid propulsion system ideal for the Roaring Fork Valley, company executives said as they showed off their prototype bus to interested locals in Glenwood Springs.

Buses using the transmission-propulsion system, powered by a mixture of combustion and electric engines and run by two controllers that act as the system’s brain, will be more ecologically friendly than the diesel buses used by the Roaring Fork Transportation Authority today.

That technology, however, comes at a cost.

A standard RFTA bus costs a little more than $300,000 brand new. A similar bus equipped with the Allison Electric Drive system would be somewhere around $500,000.

Savings in fuel consumption, cleaner air and substantial reductions in noise could make up for at least some of the added cost, officials said.

“It’s going to be quieter,” Allison’s production sales manager Chris Collet said as he stood in the walkway of the bus, telling the 30 or so passengers about the technological advances that make Allison’s drive system unique.

The passengers met at the Glenwood Springs Chamber Resort Association headquarters on Grand Avenue, and took a short ride on the high-tech bus.

“When the bus stops, it charges the batteries,” Collet said. “Instead of wasting energy and adding heat to the atmosphere, we make electricity.”

That electrical energy, according to an Allison brochure touting the technology, “is created during normal motor/generator operation and during regenerative braking.”

The hybrid system also out-accelerates standard diesel-powered buses, Collet said. Once it hits around 10 mph, the diesel engine shares the duty of running the bus, but the bus rarely relies on only the combustion engine to make it work.

The electric motor drives the initial acceleration, dampening the roar typical of a diesel engine as it starts.

Allison’s prototype bus has a 5.9-liter, 210-horsepower Cummins diesel engine, the same engine found in a full-size Dodge truck. A standard bus has an 8.9-liter, 340-horsepower diesel engine.

Aside from the drive system and the color, the Allison bus looks just like the 42-passenger buses on the road in the Roaring Fork Valley today.

Larry Michael, a transportation specialist for Allison – and the driver of the bus on Thursday – explained how the hybrid drive system was developed.

“We figured electric’s good, and diesel’s good, so we combined the best features of both,” he said.

Michael also said buying a hybrid system for a bus can show how serious a community is about being green.

“A lot of people talk about noise and pollution. But if your city gets it, they’re not only talking about it, they’re doing something about it.”

To compare the Allison bus to a RFTA bus, passengers were let out onto the sidewalk on Cooper Avenue behind the Glenwood Chamber. First the RFTA bus was accelerated and driven by. Like usual, it was fairly loud, especially after it went by, because the engine is in the rear.

Next, the Allison bus was accelerated and driven by.

“It’s quieter,” said Glenwood Springs Transportation Demand Management program director Cathy Tuttle.

The life-span of a bus is generally about 12 years, Michael said. The battery pack, however, only lasts six years, then must be replaced at a cost of around $30,000.

But despite these additional costs, Michael said fuel savings alone “would save enough money to pay for itself.”

Michael said in addition to all the other benefits, the bus also offers a smoother ride for drivers and passengers.

According to RFTA director of maintenance Kenny Osier, the buses have a 60 percent fuel improvement for city driving and somewhat less than that for highway driving.

The savings in fuel usage would probably help defray the large cost of such a drive system, he said, but the main reason RFTA is interested in possibly purchasing the buses is to quiet noise complaints.

“The real thing we get beat up on is noise,” Osier said of RFTA. “It’s more of a quality of life issue for our community. . We’re expecting it will cost more to run, but is it worth it for improvements in air quality and noise improvements?”

That’s a question that will have to be answered by members of the RFTA board.

RFTA hasn’t yet signed any deals with Allison, but Osier said he and other top RFTA officials plan to approach the RFTA Board about the possibility of buying such buses.

Allison will begin producing the system in larger quantities in October 2003. In the year following that, they expect to produce around 340 systems.

“Everywhere we’ve gone in the country, the reaction is, `How soon and when can we get this,'” Michael said.

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