Researching the effects of a hybrid bus fleet
While hybrid drivetrains have led to significant fuel economy gains for cars, it’s not necessarily the same equation for a city bus.
A typical bus gets only between four and six miles per gallon. About half of that fuel is never used to put the bus in motion.
Instead, that energy is gobbled up powering other equipment, namely systems to cool the engine and keep a window-lined interior the size of a small studio apartment at a comfortable temperature.
A year ago, two of the world’s most advanced “super hybrid” transit buses hit the road in the Twin Cities, and have beaten conventional buses on fuel economy by about 35 percent. But little is understood about how and where those benefits accrue. How much savings, for example, is due to the advanced engines versus battery-powered cooling fans?
The answers to such questions could help transit agencies identify the most cost-effective upgrades for their fleets.‘Where all the energy goes’
University of Minnesota engineering professor David Kittelson is hoping a two-year research project will yield new insights.