* Eaton system has been tested in Texas and Denver
* Fuel, maintenance savings pay back extra cost in 3 yrs
* Stores energy from braking to use during acceleration
By Bernie Woodall
ANN ARBOR, Michigan, July 28 (Reuters) - The university town of Ann Arbor, Michigan became an early adopter of a hydraulic hybrid propulsion system for big trucks that its maker Eaton Corp (ETN.N) claims will cut fuel costs and polluting emissions up to 30 percent.
Four garbage trucks to be used for recycling collection in Ann Arbor have been fitted with Eaton’s hydraulic hybrid system, which the city and Eaton unveiled on Wednesday.
The trucks made by Peterbilt Motors Co with the Eaton system added on, will use energy created by braking in a hydraulic powertrain that compliments the conventional-fueled power when the big trucks accelerate from a stop.
The hydraulic system propels the trucks that can reach 60,000 pounds fully loaded at initial acceleration, but does not store energy in batteries like most hybrid cars.
Garbage and recycling trucks stop and go up to 1,000 times per day, making good use of the short-term energy storage system, said Ann Arbor Mayor John Hieftje.
Hieftje said the Eaton hydraulic hybrid system adds $40,000 to the cost of each truck, with an expected payback in fuel and maintenance cost savings within three years.
“We think this is a potential game-changer,” said Sean Reed, executive director for the Clean Energy Coalition in Ypsilanti, Michigan.
Eaton calls its system “hydraulic launch assist.” It first began using the system on trucks last year in Fort Worth, which is near Peterbilt’s Denton, Texas headquarters, and in Dallas as well as Denver.
There are now about a dozen of similarly equipped trucks in use in the United States.
The U.S. Environmental Protection Agency helped Eaton in developing the hydraulic hybrid system as a way of lowering emissions and cutting fuel consumption.
“It’s a technology that we have been kicking the tires of for some time,” said Vincent Duray, Eaton’s chief engineer for hydraulic hybrids.
Duray said performance of the trucks in Texas have shown fuel savings of 15 percent to 25 percent and a cut in polluting emissions by 20 percent to 30 percent.
Hieftje said his staff estimates that in the 10-year life of four recycling trucks each making about 1,000 stops a day, the city will save $73,000 on fuel and $23,500 on brake system repair.
Peterbilt is a division of Paccar Inc (PCAR.O). (Reporting by Bernie Woodall, editing by Leslie Gevirtz)