A new report finds that despite consumer enthusiasm for hybrid vehicles, manufacturers have been slow to integrate hybrid technologies into commercial trucks and buses.

NextGen Research of Oyster Bay, N.Y, released the findings in its report, "Commercial Hybrid Vehicles: Heavy Trucks, Buses Get the Hybrid Treatment, Promising Greater Fuel Economy, Less Pollution."

Some manufacturers consider the efficiency of diesel engines too hard to beat, while others await fuel-cell technologies that can be integrated with commercial drivetrains, notes the report. Still others are producing and and testing concept vehicles they hope will be the cornerstones of commercial hybrid fleets.

The report forecasts the global commercial hybrid vehicle market will triple, from 8,653 units in 2008 to more than 27,000 units in 2013. NextGen Research foresees this market will begin to grow more quickly in 2010, as the global economic downturn ends and the testing of hybrid vehicles in commercial fleets is completed.

Commercial vehicles can't downsize the internal combustion engine to add an electric motor, because trucks, vans and buses need a certain level of power to make it up hills (especially when carrying full loads), and smaller engines would strain to accomplish that. Already-heavy commercial vehicles would need sizable, heavy battery packs to support an electric motor solution large enough to help propel the vehicle, but that additional weight would place more strain on the motor and the engine, and could reduce cargo capacities.

For the benefits of hybrid technology to be realized, the appropriate type of hybrid technology must be matched to a specific duty cycle. Elk Grove, California, discovered this when operating its 21 hybrid buses on predominately freeway routes; good old diesel buses handled these routes much more efficiently than the new hybrids.

Larry Fisher, research director of NextGen Research, explains, "As Elk Grove's experience makes clear, you have to match hybrids to the right duty cycle in order to reap their benefits. Low-speed stop-start drive cycles are where hybrids are superior to traditional diesels, as those scenarios allow innovations like regenerative braking to recapture much of the energy typically lost when slowing a huge, heavy vehicle. A local bus that stops every few blocks is perfectly suited to regenerative braking; for freeway driving, unless you're stuck in stop-and-go traffic, regenerative braking doesn't have the opportunity to perform."

More info: www.nextgenresearch.com