Hydraulic Launch Assist system aids productivity, conserves fuel
Dec 1, 2004 12:00 PM
Emerging technology that recycles a truck's kinetic energy to conserve fuel and aid acceleration is being jointly developed by Peterbilt Motors Co and Eaton Corp. A Peterbilt Model 320 with the Hydraulic Launch Assist (HLA) system was displayed at the recent Hybrid Truck Users Forum in Kalamazoo MI.
Initial testing shows HLA can be used to improve fuel efficiency considerably in fuel economy mode or reduce cycle times in productivity mode. In both modes, reduced brake wear of more than 50% has been observed.
From a driver's perspective, operating a vehicle equipped with the HLA system is seamless and requires no new training or skills. From a service standpoint, because it uses common hydraulic-based technologies, the system should be familiar territory for shop technicians.
HLA works by recovering a portion of the energy normally lost as heat by the vehicle's brakes, in the form of pressurized hydraulic fluid. This fluid is stored in on-board accumulators until the driver next accelerates the vehicle.
Fuel savings occur when the stored energy is then used to launch the vehicle during the initial, high-fuel-consumption start from stop, followed seamlessly by power from the primary engine. In performance mode, the stored energy is released and blended with engine power at launch. This can improve acceleration due to the high power density of hydraulics.
As a safety consideration, the HLA system is bypassed in panic-stop events, immediately activating the antilock braking system.
HLA is designed to provide maximum benefit for vehicles with 7,000 pounds or higher GVW and engaged primarily in stop-and-go work.
Peterbilt is targeting evaluation of a production representative vehicle in 2005.
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