Heavy-duty hybrid on the way

DALLAS, TX – A new joint venture formed by truck maker Paccar and component supplier Eaton Corp. plans to develop a Class 8 hybrid truck by 2009

DALLAS, TX – A new joint venture formed by truck maker Paccar and component supplier Eaton Corp. plans to develop a Class 8 hybrid truck by 2009. Eaton is providing the hybrid drivetrain system – a traction motor married to a Fuller UltraShift 10-sp. automated transmission and four lithium ion batteries – while Paccar subsidiaries Kenworth and Peterbilt provide the chassis, diesel engine, and engineering help to integrate everything.

“There will, of course, be an up-charge for buying a hybrid tractor – how much, we don’t know at this point because we are using such low volume components to build it,” Bill Jackson, Peterbilt’s gm, told Fleet Owner. “But we see many opportunities as well: fuel savings, power assistance on hills, plus a way to operate the truck’s heating and air-conditioning system without running the engine – and that’s a big issue as anti-idle regulations increase.”

Gary Moore, Kenworth’s assistant gm, told Fleet Owner that though the fuel economy savings in a heavy-duty hybrid wouldn’t be as great as those for hybrid medium-duty vehicles operating in P&D applications, payback is still there.

“Even a 1/10th improvement in fuel economy would be a huge savings to OTR fleets,” he said. “And then there are other benefits, such as power assist on hills, that can outweigh the additional weight a hybrid system would add to the vehicle. There’s going to be a payback, but we are just now getting into this, so we need to see where the benefits develop.”

Todd Graham, Eaton’s account manager for Peterbilt, explained that hybrid technology would only add about 300 lb. to a Class 8 tractor, mainly from the traction motor and power electric carrier (PEC), which holds four lithium ion batteries and replaces the standard batteries normally to power the starter. Eaton is shooting for a five-year life cycle for the lithium ion batteries, he added.

Eaton’s heavy-duty hybrid electric power system will be built using an automated manual transmission with a parallel-type “direct” hybrid system, incorporating an electric motor/generator located between the output of an automated clutch and the input to the transmission. One benefit of this approach will be that braking energy captured and then stored as electric energy in the batteries can be use to provide torque from the electric motor and blended with engine torque to improve vehicle performance, operate the engine in a more fuel-efficient range for a given speed, or run the truck with electric power only.

Getting payback, of course, is the tricky part, he told Fleet Owner. “A hybrid’s ROI (return on investment) is great in the medium-duty segment because owners keep their trucks 10 years on average,” Graham said. “In heavy-duty, however, many have a three-year trade cycle, so it’s harder to accumulate the savings in that shorter time frame.”

Another key to a commercially viable Class 8 hybrid is eliminating idle time, Landon Sproull, Peterbilt’s chief engineer, told Fleet Owner. With normal hotel loads, the hybrid’s batteries would need recharging approximately once an hour – yet the diesel engine would only need to operate for five minutes to fully recharge the system. He also noted Peterbilt has developed a “soft stop-start” algorithm for the diesel engine in order to minimize vibrations that could wake a sleeping driver.

“It’s part of looking at a hybrid truck as a complete package – offering fuel savings, power assistance and a no-idle system all in one,” Sproull said.

Graham added that Peterbilt has built one Class 8 hybrid to date, which is being delivered to Wal-Mart Transportation for field testing, and plans to build a second one, while Eaton has two Class 8 test hybrids already on the road.

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