The New York City Department of Sanitation has taken delivery of the first compressed natural gas-powered refuse truck with Bosch Rexroth's Hydrostatic Regenerative Braking (HRB) parallel hydraulic hybrid system.

The truck was featured at the Alternative Fuels & Vehicles National Conference + Expo 2010 on May 9-12 in Las Vegas. During the event, attendees had the opportunity to ride in the truck and learn more about the benefits of hydraulic hybrid technology and speak to industry experts. The project is being funded through National Grid's technology and innovation program.

"This new hybrid offers the cleaner benefits of compressed natural gas while improving fuel efficiency and torque," said Nick Stavropoulos, National Grid's executive vice president for U.S. gas distribution. "We have long been committed to carbon reduction and energy efficiency, and the transportation sector and CNG can play a vital role in moving towards a greener economy."

The trucks will be subjected to a variety of in-use testing, including braking tests, acceleration tests, route collection tests and dynamometer testing to evaluate increased capability and fuel efficiency.

The field evaluations are designed to authenticate the HRB system's ability to add needed low-end torque to the trucks' operation, replacing power lost by the use of CNG. The test will show the technical and economic benefits of the HRB system and provide real-world operating data DSNY will use to consider larger-scale deployment of the technology within the city's in-service and new vehicle fleets. In addition, the deployment demonstrates Bosch Rexroth's HRB technology is fuel neutral, working with CNG vehicles applications, as well as with traditional diesel refuse trucks.

"The HRB system gives back some of the torque lost in the switch from diesel to CNG fuel, storing energy from the vehicles' frequent braking and deceleration," said Michelle DuHadway, manager of parallel HRB accounts at Bosch Rexroth.

"New York City Department of Sanitation is thrilled to be the first refuse fleet in the nation to field test the Bosch Rexroth HRB system on a CNG-powered vehicle," said Rocco DiRico, deputy commissioner of support services for DSNY. "This is an important step toward achieving the commercialization of heavy-duty hybrid hydraulic vehicles."

The HRB system is installed in a Crane Carrier Company truck, and will be integrated with a Heil Environmental rear-loader refuse body.

The Rexroth HRB system uses a hydraulic pump/motor connected to the driveline, to capture kinetic energy during vehicle braking. When braking, the pump/motor acts as a pump, absorbing energy from the driveline and imparting a retarding force on the drive wheels, pumping hydraulic fluid into a nitrogen-pressurized accumulator. During acceleration, the pressurized gas pushes fluid out of the accumulator and the pump/motor then acts as a hydraulic motor, adding power to the engine while reducing the fuel required to launch the vehicle. This process is commonly referred to as regenerative braking.