Testing has begun on the first prototype parallel hydraulic hybrid system used in a refuse vehicle. Waste Management Inc., Fort Worth, Texas, has incorporated four parallel hydraulic hybrid-diesel collection trucks into its fleet in Fort Worth to study and optimize the hybrid system’s efficiency and reliability. This system is the first among many technologies Waste Management expects to test and implement over the coming years.Waste Management Inc. is testing four Hydraulic Launch Assist hybrid systems in its fleet

Hybrid vehicles hold great promise for the waste industry because collection vehicles have many cycles of braking and acceleration along a given route. The four Peterbilt 320 vehicles in Fort Worth use a Hydraulic Launch Assist (HLA) system developed by Eaton Corp., Eden Prairie, Minn. Brad Bohlman, business development manager of advanced technology at Eaton, says that the HLA supplements a conventional vehicle driveline with the hybrid system.

The system captures and stores energy during braking, which not only improves efficiency, but reduces wear on brake pads as well. Brake life is increased 2-4 times in vehicles doing frequent stops.Parallel hydraulic hybrid

The stored energy is transferred to accelerate the vehicle to the next pickup location, reducing fuel consumption and wear on the engine. Bohlman says a refuse vehicle that makes 1000 starts and stops a day will achieve 19 to 28% fuel economy improvement.

Waste Management will see improved productivity (e.g., more refuse pickups per day) due to the extra power the HLA system provides. Though hybrid technologies have been successfully deployed in automobiles and light trucks, Class 8 vocational vehicles such as waste trucks pose additional challenges to hybrid engine design. Among the largest vehicles on the road, Class 8 vehicles require a robust drive train that can handle heavy loads and have multiple systems — for compaction and lifting — that draw power from the engine, complicating hybrid design.

“We are working closely with manufacturers to develop and test both hydraulic and electric hybrid systems for our fleet vehicles,” said Eric Woods, vice president of fleet and logistics for Waste Management. “The challenge for our engineering team is to make our vehicles as efficient as possible while also ensuring they are tough enough to withstand wear and tear on the road. Though development is in early stages, we are optimistic that the investment we are making now will lead to a reduction in greenhouse gases and ultimately benefit both manufacturers and users of heavy vocational vehicles.”

This project is part of Waste Management’s sustainability initiative announced last year. The company has a goal to increase the fuel efficiency of its fleet by 15% and reduce fleet emissions by 15% by 2020.

For information, visit www.wm.com, www.thinkgreen.com, or www.eaton.com/hydraulics.