Peterbilt announced its plan for full production of the hybrid Model 320 Hydraulic Launch Assist (HLA) vehicle in the fourth quarter of 2008 at the 2008 Mid-America Trucking Show.

Peterbilt's low-cab-forward Model 320 Hydraulic Hybrid, for vocational stop-and-go applications such as refuse collection, uses HLA technology developed by Eaton exclusively for Paccar. The system captures the truck's kinetic energy during braking to assist in launching and accelerating the vehicle. Testing has proven a significant improvement in fuel economy, and indicated the potential to reduce annual brake re-alignment services by 50 percent annually.

"Dramatic improvements in fuel economy, reductions in emissions and lower maintenance costs spotlight the Peterbilt Model 320 Hydraulic Hybrid as the environmentally responsible, fuel-efficient solution for municipal and residential solid waste transportation fleets. These fleets operate in some of the most demanding of truck applications, often making 800-1200 stops per day on collection routes," says Bill Jackson, Peterbilt general manager and Paccar vice president.

HLA technology works by recovering up to 75 percent of the energy normally lost as heat by the vehicle's brakes in the form of pressurized hydraulic fluid. This fluid is stored in an on-board accumulator until the driver next accelerates the vehicle.

In "fuel economy mode," savings occur when stored energy is used to launch the vehicle followed seamlessly by power from the primary engine. In "performance mode," the stored energy is released and blended with engine power at launch. Here, a double-digit savings in fuel economy can still be realized, along with an 18 percent improvement in acceleration.