MANCHESTER — If you didn’t notice the word “hybrid” in green on the front fenders, it might not be evident that the two Manchester Transit Authority’s Green DASH hybrid biodiesel buses were, in fact, hybrids.
“You won’t hear our hybrid bus engine ‘shut down’ like say a Toyota Prius would when it comes to a stop in traffic,” said MTA Executive Director Mike Whitten. Nor will it run silently like a conventional hybrid car, relying solely on its battery power in city traffic.
“The engines are always ‘on’ and idling in that respect,” Whitten said. “The result is more like a boost from a turbocharger when you accelerate. You see the difference in the fuel mileage because of it.”
Unlike today’s more common hybrid cars that feature electric motors to power the vehicle at low speeds before switching to the internal combustion gas engine, the buses have a different setup.
Combined with the 230-horsepower, V-8 engine that’s mated to a 6-speed Eaton Fuller automatic transmission, an electric motor powered by a single, 340-volt, lithium ion battery, provides boost to propel the bus forward from a standing stop or uphill.
What the buses do have in common with hybrid cars is increased fuel economy, cruising range, and lower operating costs.
The difference transfers into money that the MTA has saved at the pump. The DASH buses average 6 miles per gallon compared with 4.5 miles per gallon for the non-hybrid city bus.
That difference raises the cruising range of the DASH bus to 390 miles versus the 292 of the conventional city bus.
Considering each DASH bus covers 38,000 miles annually, the hybrid requires just 6,326 gallons of biodiesel, while its non-hybrid counterpart would gulp 8,435 gallons or 2,109 gallons more to cover the same route.
All of the city’s buses use B20 biodiesel fuel. “Biodiesel uses 20 percent vegetable oil, it’s a cleaner fuel than regular, petroleum-based diesel, and it’s locally produced,” Whitten said.
The bus’s battery pack has a lifespan equivalent to that of the bus or seven years. It’s charged through regenerative braking, a process that recaptures wasted energy during normal braking, returning it to the battery pack.
Additionally, the hybrid requires no additional maintenance than a conventional transit bus.
The cost of purchasing and riding the buses is also reduced: free.
Funding from a Congestion Mitigation Air Quality three-year grant (August 2010 to September 2013) covers 80 percent of the purchase and operational costs. The difference comes from the city parking garages and meters to cover the other 20 percent. “Nothing is coming from the city general fund to operate these buses,” Whitten said. “There isn’t even a fare box on them. They’re free for anyone to use.”
The Green DASH buses run what Whitten termed a “figure 8-like” pattern on their 2.6-mile loop around downtown and Millyard every 10 minutes.
Originally, the shuttle was called the Downtown Circulator and wrapped in white and black historical photos of the Millyard. Changing the name to Green DASH emphasizes its eco-friendly nature with a catchy name. DASH is an acronym for Downtown Area Shuttle.
The bus is built by International as part of its HC Series trucks and costs less ($230,209) than a conventional transit bus ($365,000) because it’s a truck chassis outfitted with a bus body. A standard truck chassis can be produced for many uses, such as a flatbed truck or with wooden sides.
Whitten said two main companies produce most of the transit buses used throughout the country, which can only be produced when ordered and customized, requiring a longer lead time from production until delivery.
Five companies compete for the truck-based business, requiring little custom-tailoring, if any, to place a different body upon a truck chassis, resulting in a quicker turnaround time.
The 35-foot long DASH buses can seat 32 passengers, accommodate up to two wheelchairs or scooters and three bicycles on the front.
When the Congestion Mitigation Air Quality grant expires, Whitten said the city will look to utilize a Federal Transportation Administration grant to cover 50 percent of the costs and make up the remaining half of the costs through parking fees, as it does now, to operate without assistance from the city’s general fund.