The exclusive joint venture formed by truck maker Paccar and component supplier Eaton Corp. to develop a production-ready Class 8 hybrid tractor by 2009 is now transitioning into “second generation” test vehicles based on data gleaned from work conducted so far.
Both Paccar and Eaton are working with Wal-Mart exclusively to test the hybrid Class 8 truck, and the field data comes from Wal-Mart’s use of the vehicle in over-the-road operations.
“Our first task was to just get all the components on there – the electric motor, battery back, and transmission – to show it could work and handle the duty cycle,” Landon Sproull, Peterbilt Motor Co.’s chief engineer, told FleetOwner. “Now we’re moving into the second generation of this technology, where we are trying to refine the entire package to improve overall efficiency.”
For example, Bill Kahn, Peterbilt’s hybrid project manager, told FleetOwner that the diesel fuel capacity on the Model 386 tractor used as the base chassis for Peterbilt’s part of the hybrid project has been reduced 15% as a result of the fuel economy gains demonstrated so far in field tests. Peterbilt’s sister company, Kenworth Truck Co., also has a tractor involved.
“We’re also now working with a couple of different axle ratios and we’re trying to close the tractor-trailer gap to improve fuel economy further,” he said.
Currently, Peterbilt’s hybrid Model 386 is equipped with a Cummins ISX 400 hp engine married to an Eaton traction motor and Fuller UltraShift 10-speed automated transmission, along with four lithium ion batteries mounted on the back of the cab.
The goal of this project remains the same: to be able to use electric power not only to aid on-road vehicle operation but also to provide cooling, heat, and hotel loads without idling the engine, said Sproull. Testing is ongoing in cold, hot, and high-altitude conditions with trucks primarily in sleeper configurations.
“For the third generation of this package, we’re looking at using a bigger electric motor, provide more energy storage capacity, and take ‘parasitic loads’ off the engine, such as operating the engine fan, water pump, etc.,” Sproull noted. “The challenges we face right now are how the components will hold up over the life cycle of the vehicle, as many of the components on today’s trucks are not designed to handle the voltage levels we’re using.”
He added that interest in this Class 8 hybrid project is growing by leaps and bounds, though test trucks are exclusive to Wal-Mart and will remain so for the future. “We never anticipated when we started this that diesel fuel would reach $4 a gallon – that’s putting tremendous pressure on the bottom line of fleets and they are looking intensely for ways to cut that cost,” he said. “I tell you, we’re getting inquiries from a lot of major fleets as to when this technology may become available. The industry is really engaged in this and looking for ways this technology can benefit them.